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Ding N, Song Y, Zhang Y, Yu W, Li X, Li W, Li L. Heat-shock chaperone HSPB1 mitigates poly-glycine-induced neurodegeneration via restoration of autophagic flux. Autophagy 2025; 21:1298-1315. [PMID: 39936620 DOI: 10.1080/15548627.2025.2466144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2024] [Revised: 02/03/2025] [Accepted: 02/07/2025] [Indexed: 02/13/2025] Open
Abstract
The CGG repeat expansions in the 5'-UTR regions of certain genes have been implicated in various neurodegenerative and muscular disorders. However, the underlying pathogenic mechanisms are not well understood. In this study, we explore the role of the small molecular chaperone HSPB1 in counteracting neurodegeneration induced by poly-glycine (poly-G) aggregates. Employing a reporter system, we demonstrate that CGG repeat expansions within the 5'-UTR of the GIPC1 gene produce poly-G proteins, by repeat-associated non-AUG (RAN) translation. Through proximity labeling and subsequent mass spectrometry analysis, we characterize the composition of poly-G insoluble aggregates and reveal that these aggregates sequester key macroautophagy/autophagy receptors, SQSTM1/p62 and TOLLIP. This sequestration disrupts MAP1LC3/LC3 recruitment and impairs autophagosome formation, thereby compromising the autophagic pathway. Importantly, we show that HSPB1 facilitates the dissociation of these receptors from poly-G aggregates and consequently restores autophagic function. Overexpressing HSPB1 alleviates poly-G-induced neurodegeneration in mouse models. Taken together, these findings highlight a mechanistic basis for the neuroprotective effects of HSPB1 and suggest its potential as a therapeutic target in treating poly-G-associated neurodegenerative diseases.Abbreviations: AD: Alzheimer disease; AIF1/Iba1: allograft inflammatory factor 1; Baf A1: bafilomycin A1; BFP: blue fluorescent protein; CQ: chloroquine; EIF2A/eIF-2α: eukaryotic translation initiation factor 2A; FRAP: fluorescence recovery after photobleaching; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFAP: glial fibrillary acidic protein; GFP: green fluorescent protein; HSPB1: heat shock protein family B (small) member 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; NOTCH2NLC: notch 2 N-terminal like C; PD: Parkinson disease; PFA: paraformaldehyde; poly-A: poly-alanine; poly-G: poly-glycine; poly-R: poly-arginine; RAN translation: repeat-associated non-AUG translation; RBFOX3/NeuN: RNA binding fox-1 homolog 3; STED: stimulated emission depletion; TARDBP/TDP-43: TAR DNA binding protein; TG: thapsigargin; TOLLIP: toll interacting protein.
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Affiliation(s)
- Ning Ding
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yijie Song
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yuhang Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wei Yu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xinnan Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Lingang Laboratory, Shanghai, China
| | - Wei Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Shanghai Clinical Research and Trial Center, Shanghai, China
| | - Lei Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Shanghai Clinical Research and Trial Center, Shanghai, China
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Tutak K, Broniarek I, Zielezinski A, Niewiadomska D, Skrzypczak T, Baud A, Sobczak K. Insufficiency of 40S ribosomal proteins, RPS26 and RPS25, negatively affects biosynthesis of polyglycine-containing proteins in fragile-X associated conditions. eLife 2025; 13:RP98631. [PMID: 40377206 DOI: 10.7554/elife.98631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2025] Open
Abstract
Expansion of CGG repeats (CGGexp) in the 5' untranslated region (5'UTR) of the FMR1 gene underlies the fragile X premutation-associated conditions including tremor/ataxia syndrome, a late-onset neurodegenerative disease and fragile X-associated primary ovarian insufficiency. One common pathomechanism of these conditions is the repeat-associated non-AUG-initiated (RAN) translation of CGG repeats of mutant FMR1 mRNA, resulting in production of FMRpolyG, a toxic protein containing long polyglycine tract. To identify novel modifiers of RAN translation we used an RNA-tagging system and mass spectrometry-based screening. It revealed proteins enriched on CGGexp-containing FMR1 RNA in cellulo, including a ribosomal protein RPS26, a component of the 40 S subunit. We demonstrated that depletion of RPS26 and its chaperone TSR2, modulates FMRpolyG production and its toxicity. We also found that the RPS26 insufficiency impacted translation of limited number of proteins, and 5'UTRs of mRNAs encoding these proteins were short and guanosine and cytosine-rich. Moreover, the silencing of another component of the 40 S subunit, the ribosomal protein RPS25, also induced repression of FMRpolyG biosynthesis. Results of this study suggest that the two 40 S ribosomal proteins and chaperone TSR2 play an important role in noncanonical CGGexp-related RAN translation.
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Affiliation(s)
- Katarzyna Tutak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznan, Poland
| | - Izabela Broniarek
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznan, Poland
| | - Andrzej Zielezinski
- Department of Computational Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Uniwersytetu Poznańskiego 6, Poznan, Poland
| | - Daria Niewiadomska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznan, Poland
| | - Tomasz Skrzypczak
- Center of Advanced Technology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, Poznan, Poland
| | - Anna Baud
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznan, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznan, Poland
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Hölbling BV, Gupta Y, Marchi PM, Atilano ML, Flower M, Ureña E, Goulden RA, Dobbs HK, Katona E, Mikheenko A, Giblin A, Awan AR, Fisher-Ward CL, O'Brien N, Vaizoglu D, Kempthorne L, Wilson KM, Gittings LM, Carcolé M, Ruepp MD, Mizielinska S, Partridge L, Fratta P, Tabrizi SJ, Selvaraj BT, Chandran S, Armstrong E, Whiting P, Isaacs AM. A multimodal screening platform for endogenous dipeptide repeat proteins in C9orf72 patient iPSC neurons. Cell Rep 2025; 44:115695. [PMID: 40349338 DOI: 10.1016/j.celrep.2025.115695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/04/2024] [Accepted: 04/23/2025] [Indexed: 05/14/2025] Open
Abstract
Repeat expansions in C9orf72 are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia. Repeat-associated non-AUG (RAN) translation generates neurotoxic dipeptide repeat proteins (DPRs). To study endogenous DPRs, we inserted the minimal HiBiT luciferase reporter downstream of sense repeat derived DPRs polyGA or polyGP in C9orf72 patient iPSCs. We show these "DPReporter" lines sensitively and rapidly report DPR levels in lysed and live cells and optimize screening in iPSC neurons. Small-molecule screening showed the ERK1/2 activator periplocin dose dependently increases DPR levels. Consistent with this, ERK1/2 inhibition reduced DPR levels and prolonged survival in C9orf72 repeat expansion flies. CRISPR knockout screening of all human helicases revealed telomere-associated helicases modulate DPR expression, suggesting common regulation of telomeric and C9orf72 repeats. These DPReporter lines allow investigation of DPRs in their endogenous context and provide a template for studying endogenous RAN-translated proteins, at scale, in other repeat expansion disorders.
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Affiliation(s)
- Benedikt V Hölbling
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Yashica Gupta
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Paolo M Marchi
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Magda L Atilano
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, UCL, London, UK
| | - Michael Flower
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Enric Ureña
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, UCL, London, UK
| | - Rajkumar A Goulden
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, UCL, London, UK
| | - Hannah K Dobbs
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Eszter Katona
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Alla Mikheenko
- UK Dementia Research Institute at UCL, London, UK; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Ashling Giblin
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK; Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, UCL, London, UK
| | - Ali Raza Awan
- Genomics Innovation Unit, Guy's and St Thomas' NHS Trust, London, UK; Comprehensive Cancer Centre, King's College London, London, UK
| | | | - Niamh O'Brien
- UK Dementia Research Institute at King's College London, London, UK; Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Deniz Vaizoglu
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Liam Kempthorne
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Katherine M Wilson
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Lauren M Gittings
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Mireia Carcolé
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Marc-David Ruepp
- UK Dementia Research Institute at King's College London, London, UK; Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, UK; Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Linda Partridge
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, UCL, London, UK
| | - Pietro Fratta
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK; The Francis Crick Institute, London, UK
| | - Sarah J Tabrizi
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Bhuvaneish T Selvaraj
- UK Dementia Research Institute at University of Edinburgh, Edinburgh, UK; Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Siddharthan Chandran
- UK Dementia Research Institute at University of Edinburgh, Edinburgh, UK; Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Emma Armstrong
- Alzheimer's Research UK Drug Discovery Institute, UCL, London, UK
| | - Paul Whiting
- UK Dementia Research Institute at UCL, London, UK; Alzheimer's Research UK Drug Discovery Institute, UCL, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK.
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4
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Paracuellos-Ayala I, Caruana G, Reyes Ortega MM, Hagerman RJ, Wang JY, Rodriguez-Revenga L, Elias-Mas A. Involvement of the Cerebellar Peduncles in FMR1 Premutation Carriers: A Pictorial Review of Their Anatomy, Imaging, and Pathology. Int J Mol Sci 2025; 26:4402. [PMID: 40362640 PMCID: PMC12072475 DOI: 10.3390/ijms26094402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2025] [Revised: 04/29/2025] [Accepted: 05/02/2025] [Indexed: 05/15/2025] Open
Abstract
The cerebellar peduncles (CPs) contain essential pathways connecting the cerebellum and other regions of the central nervous system, yet their role is often overlooked in daily medical practice. Individuals with the FMR1 premutation are at risk of developing fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder. The major clinical and radiological signs of FXTAS are cerebellar gait ataxia, intention tremor, and T2-weighted MRI hyperintensity of the middle cerebellar peduncle (MCP sign). Over the years, metabolic and structural abnormalities have also been described in the CPs of FMR1 premutation carriers, with some being associated with CGG repeat length and FMR1 mRNA levels. Evidence seems to associate the clinical disfunction observed in FXTAS with MCP abnormalities. However, other tracts within the different CPs may also contribute to the symptoms observed in FXTAS. By integrating imaging and pathological data, this review looks to enhance the understanding of the functional anatomy of the CPs and their involvement in different pathological entities, with special interest in premutation carriers and FXTAS. This review, therefore, aims to provide accessible knowledge on the subject of the CPs and their functional anatomy through detailed diagrams, offering a clearer understanding of their role in FMR1 premutation.
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Affiliation(s)
- Irene Paracuellos-Ayala
- Radiology Department, Hospital Universitari Mútua Terrassa (HUMT), Terrassa 08221, Spain; (I.P.-A.); (G.C.); (M.M.R.O.); (A.E.-M.)
| | - Giovanni Caruana
- Radiology Department, Hospital Universitari Mútua Terrassa (HUMT), Terrassa 08221, Spain; (I.P.-A.); (G.C.); (M.M.R.O.); (A.E.-M.)
| | - Macarena Maria Reyes Ortega
- Radiology Department, Hospital Universitari Mútua Terrassa (HUMT), Terrassa 08221, Spain; (I.P.-A.); (G.C.); (M.M.R.O.); (A.E.-M.)
| | - Randi J. Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA 95817, USA;
- Department of Pediatrics, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Jun Yi Wang
- Center for Mind and Brain, University of California Davis, Davis, CA 95618, USA;
| | - Laia Rodriguez-Revenga
- Biochemistry and Molecular Genetics Department, Hospital Clinic of Barcelona, 08036 Barcelona, Spain
- CIBER of Rare Diseases (CIBERER), Instituto de Salud Carlos III, 08036 Barcelona, Spain
- Fundació de Recerca Clínic Barcelona-Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Andrea Elias-Mas
- Radiology Department, Hospital Universitari Mútua Terrassa (HUMT), Terrassa 08221, Spain; (I.P.-A.); (G.C.); (M.M.R.O.); (A.E.-M.)
- Genetics Doctorate Program, Universitat de Barcelona (UB), 08036 Barcelona, Spain
- Institute for Research and Innovation Parc Taulí (I3PT), 08208 Sabadell, Spain
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5
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Ishiura H. Recent progress in oculopharyngodistal myopathy research from clinical and genetic viewpoints. J Neuromuscul Dis 2025:22143602251319164. [PMID: 40033734 DOI: 10.1177/22143602251319164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2025]
Abstract
Oculopharyngodistal myopathy (OPDM) is a rare muscular disorder characterized by ocular symptoms, pharyngeal symptoms, facial weakness, and distal predominant limb muscle weakness. The cause of the disease was unknown for a long time. Recently, however, it has been reported that expansions of CGG or CCG repeats in LRP12, LOC642361/NUTM2B-AS1, GIPC1, NOTCH2NLC, RILPL1, and ABCD3 are the causes of the disease. Cases sometimes present with neurological symptoms, and the clinical spectrum of diseases caused by expansions of CGG or CCG repeats has been proposed to be called FNOP-spectrum disorder after the names of fragile X-associated tremor/ataxia syndrome, neuronal intranuclear inclusion disease, oculopharyngeal myopathy with leukoencephalopathy, and OPDM. In this article, the recent progress in the field of OPDM is reviewed, and remaining issues in OPDM are discussed.
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Affiliation(s)
- Hiroyuki Ishiura
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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6
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An Z, Jiang A, Chen J. Toward understanding the role of genomic repeat elements in neurodegenerative diseases. Neural Regen Res 2025; 20:646-659. [PMID: 38886931 PMCID: PMC11433896 DOI: 10.4103/nrr.nrr-d-23-01568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/21/2023] [Accepted: 03/02/2024] [Indexed: 06/20/2024] Open
Abstract
Neurodegenerative diseases cause great medical and economic burdens for both patients and society; however, the complex molecular mechanisms thereof are not yet well understood. With the development of high-coverage sequencing technology, researchers have started to notice that genomic repeat regions, previously neglected in search of disease culprits, are active contributors to multiple neurodegenerative diseases. In this review, we describe the association between repeat element variants and multiple degenerative diseases through genome-wide association studies and targeted sequencing. We discuss the identification of disease-relevant repeat element variants, further powered by the advancement of long-read sequencing technologies and their related tools, and summarize recent findings in the molecular mechanisms of repeat element variants in brain degeneration, such as those causing transcriptional silencing or RNA-mediated gain of toxic function. Furthermore, we describe how in silico predictions using innovative computational models, such as deep learning language models, could enhance and accelerate our understanding of the functional impact of repeat element variants. Finally, we discuss future directions to advance current findings for a better understanding of neurodegenerative diseases and the clinical applications of genomic repeat elements.
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Affiliation(s)
- Zhengyu An
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Aidi Jiang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Jingqi Chen
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
- MOE Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Shanghai, China
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7
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Oguro A, Uemura T, Machida K, Kitajiri K, Tajima A, Furuchi T, Kawai G, Imataka H. Polyamines enhance repeat-associated non-AUG translation from CCUG repeats by stabilizing the tertiary structure of RNA. J Biol Chem 2025; 301:108251. [PMID: 39894221 PMCID: PMC11919584 DOI: 10.1016/j.jbc.2025.108251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 01/22/2025] [Accepted: 01/24/2025] [Indexed: 02/04/2025] Open
Abstract
Repeat expansion disorders are caused by abnormal expansion of microsatellite repeats. Repeat-associated non-AUG (RAN) translation is one of the pathogenic mechanisms underlying repeat expansion disorders, but the exact molecular mechanism underlying RAN translation remains unclear. Polyamines are ubiquitous biogenic amines that are essential for cell proliferation and cellular functions. They are predominantly found in cells in complexes with RNA and influence many cellular events, but the relationship between polyamines and RAN translation is yet to be explored. Here, we show that, in both a cell-free protein synthesis system and cell culture, polyamines promote RAN translation of RNA-containing CCUG repeats. The CCUG-dependent RAN translation is suppressed when cells are depleted of polyamines but can be recovered by the addition of polyamines. Thermal stability analysis revealed that the tertiary structure of the CCUG-repeat RNA is stabilized by the polyamines. Spermine was the most effective polyamine for stabilizing CCUG-repeat RNA and enhancing RAN translation. These results suggest that polyamines, particularly spermine, modulate RAN translation of CCUG-repeat RNA by stabilizing the tertiary structure of the repeat RNA.
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Affiliation(s)
- Akihiro Oguro
- Division of Physical Fitness, Department of Molecular Physiology, The Jikei University School of Medicine, Tokyo, Japan.
| | - Takeshi Uemura
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Kodai Machida
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Japan
| | - Kanta Kitajiri
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Japan
| | - Ayasa Tajima
- Department of Molecular Biology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takemitsu Furuchi
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Gota Kawai
- Department of Life Science, Faculty of Advanced Engineering, Chiba Institute of Technology, Chiba, Japan
| | - Hiroaki Imataka
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Japan.
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Chase A, Hamrick L, Arnold H, Smith J, Hantman R, Cortez K, Adayev T, Tortora ND, Dahlman A, Roberts J. Reduced Respiratory Sinus Arrhythmia in Infants with the FMR1 Premutation. Int J Mol Sci 2025; 26:2186. [PMID: 40076819 PMCID: PMC11900448 DOI: 10.3390/ijms26052186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2025] [Revised: 02/21/2025] [Accepted: 02/24/2025] [Indexed: 03/14/2025] Open
Abstract
The fragile X premutation (FXpm) is caused by a CGG repeat expansion on the FMR1 gene. In adults, FXpm is linked with autonomic nervous system (ANS) dysfunction and impairment is associated with CGG repeat length. Given scant infancy research, we examined ANS functioning, via respiratory sinus arrhythmia (RSA) and interbeat interval (IBI), in 82 FXpm and neurotypical infants and their associations with CGG repeats. FXpm infants exhibited lower RSA but no IBI differences. There were no associations between ANS functioning and CGG repeat length. These findings identify an ANS biomarker consistent with the emerging pediatric phenotype in FXpm.
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Affiliation(s)
- Abigail Chase
- School of Medicine, University of South Carolina, Columbia, SC 29209, USA;
| | - Lisa Hamrick
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (L.H.); (H.A.); (J.S.); (R.H.); (K.C.); (A.D.)
- Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, SC 29208, USA
| | - Holley Arnold
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (L.H.); (H.A.); (J.S.); (R.H.); (K.C.); (A.D.)
- Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, SC 29208, USA
| | - Jenna Smith
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (L.H.); (H.A.); (J.S.); (R.H.); (K.C.); (A.D.)
- Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, SC 29208, USA
| | - Rachel Hantman
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (L.H.); (H.A.); (J.S.); (R.H.); (K.C.); (A.D.)
- Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, SC 29208, USA
| | - Kaitlyn Cortez
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (L.H.); (H.A.); (J.S.); (R.H.); (K.C.); (A.D.)
- Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, SC 29208, USA
| | - Tatyana Adayev
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, New York, NY 10314, USA; (T.A.); (N.D.T.)
| | - Nicole D. Tortora
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, New York, NY 10314, USA; (T.A.); (N.D.T.)
| | - Alison Dahlman
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (L.H.); (H.A.); (J.S.); (R.H.); (K.C.); (A.D.)
- Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, SC 29208, USA
| | - Jane Roberts
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (L.H.); (H.A.); (J.S.); (R.H.); (K.C.); (A.D.)
- Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, SC 29208, USA
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9
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Jung S, Richter JD. Trinucleotide repeat expansion and RNA dysregulation in fragile X syndrome: emerging therapeutic approaches. RNA (NEW YORK, N.Y.) 2025; 31:307-313. [PMID: 39725461 PMCID: PMC11874960 DOI: 10.1261/rna.080270.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2024] [Accepted: 12/23/2024] [Indexed: 12/28/2024]
Abstract
Fragile X syndrome (FXS) is characterized by intellectual impairment caused by CGG repeat expansion in the FMR1 gene. When repeats exceed 200, they induce DNA methylation of the promoter and the repeat region, resulting in transcriptional silencing of the FMR1 gene and the subsequent loss of FMRP protein. In the past decade or so, research has focused on the role of FMRP as an RNA-binding protein involved in translation inhibition in the brain in FXS model mice, particularly by slowing or stalling ribosome translocation on mRNA. More recent advances have shown that FMRP has a profound role in RNA splicing, at least in some cases by modulating the translation of splicing factor mRNAs. In a surprise, the human FMR1 gene is transcribed in most cases even with a full CGG expansion. However, much of the FMR1 that is produced is misspliced, which can be corrected by splice-switching antisense oligonucleotide (ASO) administration. Other recent findings suggest that inhibition of multiple kinases can demethylate the FMR1 gene and induce the formation of an R-loop in the CGG repeat region, leading to contraction of the repeat and FMRP restoration. These insights are paving the way for possible future therapeutic approaches for this disorder. We highlight the importance of FMRP restoration by ASO-mediated splice switching or CGG repeat modulation as key advances that may lead to successful treatments for FXS.
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Affiliation(s)
- Suna Jung
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts 01605, USA
| | - Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts 01605, USA
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10
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Kul E, Santos M, Stork O. Nigrostriatal Degeneration Underpins Sensorimotor Dysfunction in an Inducible Mouse Model of Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS). Int J Mol Sci 2025; 26:1511. [PMID: 40003975 PMCID: PMC11855849 DOI: 10.3390/ijms26041511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2024] [Revised: 02/07/2025] [Accepted: 02/10/2025] [Indexed: 02/27/2025] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder caused by moderately expanded CGG trinucleotide repeats in the 5' untranslated region (UTR) of the FMR1 gene. Characterized by motor deficits such as action tremor and cerebellar gait ataxia, FXTAS is further distinguished by ubiquitin-positive intranuclear inclusions in neurons and glia. However, its clinical spectrum often overlaps with other neurodegenerative conditions such as Parkinson's disease (PD). Sensorimotor gating deficits, commonly associated with disorders affecting the nigrostriatal pathway such as PD, have been reported in FXTAS, but the underlying connection between these two phenotypes remains undetermined. In this study, we used the P90CGG mouse model of FXTAS, which expresses 90 CGG repeats upon doxycycline induction, to investigate sensorimotor gating deficits and their relationship to nigrostriatal degeneration. After induction, the P90CGG model exhibited late-onset impairments in prepulse inhibition (PPI), a cross-species measure of sensorimotor gating. These deficits coincided with pronounced nigrostriatal degeneration but occurred without evidence of inclusion formation in the substantia nigra. Our findings highlight nigrostriatal degeneration, which has not previously been reported in animal models of FXTAS, and suggest a potential link to sensorimotor gating dysfunction within the context of the disorder.
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Affiliation(s)
- Emre Kul
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, 39106 Magdeburg, Germany; (E.K.); (M.S.)
| | - Mónica Santos
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, 39106 Magdeburg, Germany; (E.K.); (M.S.)
| | - Oliver Stork
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, 39106 Magdeburg, Germany; (E.K.); (M.S.)
- Center for Behavioral Brain Sciences, 39106 Magdeburg, Germany
- Center for Intervention and Research on Adaptive and Maladaptive Brain Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, 07743 Jena, Germany
- German Center for Mental Health (DZPG), Site Jena-Magdeburg-Halle, 07745 Jena, Germany
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11
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Hobara T, Ando M, Higuchi Y, Yuan JH, Yoshimura A, Kojima F, Noguchi Y, Takei J, Hiramatsu Y, Nozuma S, Nakamura T, Adachi T, Toyooka K, Yamashita T, Sakiyama Y, Hashiguchi A, Matsuura E, Okamoto Y, Takashima H. Linking LRP12 CGG repeat expansion to inherited peripheral neuropathy. J Neurol Neurosurg Psychiatry 2025; 96:140-149. [PMID: 39013564 PMCID: PMC11877035 DOI: 10.1136/jnnp-2024-333403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 06/12/2024] [Indexed: 07/18/2024]
Abstract
BACKGROUND The causative genes for over 60% of inherited peripheral neuropathy (IPN) remain unidentified. This study endeavours to enhance the genetic diagnostic rate in IPN cases by conducting screenings focused on non-coding repeat expansions. METHODS We gathered data from 2424 unrelated Japanese patients diagnosed with IPN, among whom 1555 cases with unidentified genetic causes, as determined through comprehensive prescreening analyses, were selected for the study. Screening for CGG non-coding repeat expansions in LRP12, GIPC1 and RILPL1 genes was conducted using PCR and long-read sequencing technologies. RESULTS We identified CGG repeat expansions in LRP12 from 44 cases, establishing it as the fourth most common aetiology in Japanese IPN. Most cases (29/37) exhibited distal limb weakness, without ptosis, ophthalmoplegia, facial muscle weakness or bulbar palsy. Neurogenic changes were frequently observed in both needle electromyography (97%) and skeletal muscle tissue (100%). In nerve conduction studies, 28 cases primarily showed impairment in motor nerves without concurrent involvement of sensory nerves, consistent with the phenotype of hereditary motor neuropathy. In seven cases, both motor and sensory nerves were affected, resembling the Charcot-Marie-Tooth (CMT) phenotype. Importantly, the mean CGG repeat number detected in the present patients was significantly shorter than that of patients with LRP12-oculopharyngodistal myopathy (p<0.0001). Additionally, GIPC1 and RILPL1 repeat expansions were absent in our IPN cases. CONCLUSION We initially elucidate LRP12 repeat expansions as a prevalent cause of CMT, highlighting the necessity for an adapted screening strategy in clinical practice, particularly when addressing patients with IPN.
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Affiliation(s)
- Takahiro Hobara
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Masahiro Ando
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yujiro Higuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Jun-Hui Yuan
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akiko Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Fumikazu Kojima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yutaka Noguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Jun Takei
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yu Hiramatsu
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Satoshi Nozuma
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tomonori Nakamura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tadashi Adachi
- Division of Neuropathology, Department of Brain and Neurosciences, Tottori University Faculty of Medicine, Tottori, Japan
| | - Keiko Toyooka
- Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, Osaka, Japan
| | - Toru Yamashita
- Department of Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Yusuke Sakiyama
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akihiro Hashiguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Eiji Matsuura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- Department of Physical Therapy, Kagoshima University Faculty of Medicine School of Health Sciences, Kagoshima, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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12
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Gillett DA, Tigro H, Wang Y, Suo Z. FMR1 Disorders: Basics of Biology and Therapeutics in Development. Cells 2024; 13:2100. [PMID: 39768191 PMCID: PMC11674747 DOI: 10.3390/cells13242100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2024] [Revised: 12/04/2024] [Accepted: 12/13/2024] [Indexed: 01/11/2025] Open
Abstract
Fragile X Syndrome (FXS) presents with a constellation of phenotypes, including trouble regulating emotion and aggressive behaviors, disordered sleep, intellectual impairments, and atypical physical development. Genetic study of the X chromosome revealed that substantial repeat expansion of the 5' end of the gene fragile X messenger ribonucleoprotein 1 (FMR1) promoted DNA methylation and, consequently, silenced expression of FMR1. Further analysis proved that shorter repeat expansions in FMR1 also manifested in disease at later stages in life. Treatment and therapy options do exist, but they only manage symptoms. Up to now, no cure for FMR1 disorders exists. In this review, we aim to provide an overview of FMR1 biology and the latest research focused on developing therapeutic interventions that can potentially prevent and/or reverse FXS.
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Affiliation(s)
| | | | | | - Zucai Suo
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
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13
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Zhang Y, Liu X, Li Z, Li H, Miao Z, Wan B, Xu X. Advances on the Mechanisms and Therapeutic Strategies in Non-coding CGG Repeat Expansion Diseases. Mol Neurobiol 2024; 61:10722-10735. [PMID: 38780719 DOI: 10.1007/s12035-024-04239-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/02/2024] [Indexed: 05/25/2024]
Abstract
Non-coding CGG repeat expansions within the 5' untranslated region are implicated in a range of neurological disorders, including fragile X-associated tremor/ataxia syndrome, oculopharyngeal myopathy with leukodystrophy, and oculopharyngodistal myopathy. This review outlined the general characteristics of diseases associated with non-coding CGG repeat expansions, detailing their clinical manifestations and neuroimaging patterns, which often overlap and indicate shared pathophysiological traits. We summarized the underlying molecular mechanisms of these disorders, providing new insights into the roles that DNA, RNA, and toxic proteins play. Understanding these mechanisms is crucial for the development of targeted therapeutic strategies. These strategies include a range of approaches, such as antisense oligonucleotides, RNA interference, genomic DNA editing, small molecule interventions, and other treatments aimed at correcting the dysregulated processes inherent in these disorders. A deeper understanding of the shared mechanisms among non-coding CGG repeat expansion disorders may hold the potential to catalyze the development of innovative therapies, ultimately offering relief to individuals grappling with these debilitating neurological conditions.
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Affiliation(s)
- Yutong Zhang
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Xuan Liu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Zeheng Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Hao Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
- Department of Neurology, The Fourth Affiliated Hospital of Soochow University, Suzhou, 215124, China
| | - Zhigang Miao
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Bo Wan
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Xingshun Xu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China.
- The Institute of Neuroscience, Soochow University, Suzhou City, China.
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, 215000, China.
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14
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Chang WD, Yoon MJ, Yeo KH, Choe YJ. Threonine-rich carboxyl-terminal extension drives aggregation of stalled polypeptides. Mol Cell 2024; 84:4334-4349.e7. [PMID: 39488212 DOI: 10.1016/j.molcel.2024.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 08/01/2024] [Accepted: 10/09/2024] [Indexed: 11/04/2024]
Abstract
Ribosomes translating damaged mRNAs may stall and prematurely split into their large and small subunits. The split large ribosome subunits can continue elongating stalled polypeptides. In yeast, this mRNA-independent translation appends the C-terminal alanine/threonine tail (CAT tail) to stalled polypeptides. If not degraded by the ribosome-associated quality control (RQC), CAT-tailed stalled polypeptides form aggregates. How the CAT tail, a low-complexity region composed of alanine and threonine, drives protein aggregation remains unknown. In this study, we demonstrate that C-terminal polythreonine or threonine-enriched tails form detergent-resistant aggregates. These aggregates exhibit a robust seeding effect on shorter tails with lower threonine content, elucidating how heterogeneous CAT tails co-aggregate. Polythreonine aggregates sequester molecular chaperones, disturbing proteostasis and provoking the heat shock response. Furthermore, polythreonine cross-seeds detergent-resistant polyserine aggregation, indicating structural similarity between the two aggregates. This study identifies polythreonine and polyserine as a distinct group of aggregation-prone protein motifs.
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Affiliation(s)
- Weili Denyse Chang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Mi-Jeong Yoon
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Kian Hua Yeo
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Young-Jun Choe
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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15
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Broniarek I, Niewiadomska D, Sobczak K. Contribution of DNA/RNA Structures Formed by Expanded CGG/CCG Repeats Within the FMR1 Locus in the Pathogenesis of Fragile X-Associated Disorders. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1874. [PMID: 39523485 DOI: 10.1002/wrna.1874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 09/05/2024] [Accepted: 09/09/2024] [Indexed: 11/16/2024]
Abstract
Repeat expansion disorders (REDs) encompass over 50 inherited neurological disorders and are characterized by the expansion of short tandem nucleotide repeats beyond a specific repeat length. Particularly intriguing among these are multiple fragile X-associated disorders (FXds), which arise from an expansion of CGG repeats in the 5' untranslated region of the FMR1 gene. Despite arising from repeat expansions in the same gene, the clinical manifestations of FXds vary widely, encompassing developmental delays, parkinsonism, dementia, and an increased risk of infertility. FXds also exhibit molecular mechanisms observed in other REDs, that is, gene- and protein-loss-of-function and RNA- and protein-gain-of-function. The heterogeneity of phenotypes and pathomechanisms in FXds results from the different lengths of the CGG tract. As the number of repeats increases, the structures formed by RNA and DNA fragments containing CGG repeats change significantly, contributing to the diversity of FXd phenotypes and mechanisms. In this review, we discuss the role of RNA and DNA structures formed by expanded CGG repeats in driving FXd pathogenesis and how the genetic instability of CGG repeats is mediated by the complex interplay between transcription, DNA replication, and repair. We also discuss therapeutic strategies, including small molecules, antisense oligonucleotides, and CRISPR-Cas systems, that target toxic RNA and DNA involved in the development of FXds.
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Affiliation(s)
- Izabela Broniarek
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Daria Niewiadomska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
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16
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Han TW, Portz B, Young RA, Boija A, Klein IA. RNA and condensates: Disease implications and therapeutic opportunities. Cell Chem Biol 2024; 31:1593-1609. [PMID: 39303698 DOI: 10.1016/j.chembiol.2024.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 08/14/2024] [Accepted: 08/21/2024] [Indexed: 09/22/2024]
Abstract
Biomolecular condensates are dynamic membraneless organelles that compartmentalize proteins and RNA molecules to regulate key cellular processes. Diverse RNA species exert their effects on the cell by their roles in condensate formation and function. RNA abnormalities such as overexpression, modification, and mislocalization can lead to pathological condensate behaviors that drive various diseases, including cancer, neurological disorders, and infections. Here, we review RNA's role in condensate biology, describe the mechanisms of RNA-induced condensate dysregulation, note the implications for disease pathogenesis, and discuss novel therapeutic strategies. Emerging approaches to targeting RNA within condensates, including small molecules and RNA-based therapies that leverage the unique properties of condensates, may revolutionize treatment for complex diseases.
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Affiliation(s)
| | | | - Richard A Young
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ann Boija
- Dewpoint Therapeutics, Boston, MA, USA.
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17
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Glineburg M, Yildirim E, Gomez N, Rodriguez G, Pak J, Li X, Altheim C, Waksmacki J, McInerney G, Barmada S, Todd P. Stress granule formation helps to mitigate neurodegeneration. Nucleic Acids Res 2024; 52:9745-9759. [PMID: 39106168 PMCID: PMC11381325 DOI: 10.1093/nar/gkae655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 05/28/2024] [Accepted: 07/17/2024] [Indexed: 08/09/2024] Open
Abstract
Cellular stress pathways that inhibit translation initiation lead to transient formation of cytoplasmic RNA/protein complexes known as stress granules. Many of the proteins found within stress granules and the dynamics of stress granule formation and dissolution are implicated in neurodegenerative disease. Whether stress granule formation is protective or harmful in neurodegenerative conditions is not known. To address this, we took advantage of the alphavirus protein nsP3, which selectively binds dimers of the central stress granule nucleator protein G3BP and markedly reduces stress granule formation without directly impacting the protein translational inhibitory pathways that trigger stress granule formation. In Drosophila and rodent neurons, reducing stress granule formation with nsP3 had modest impacts on lifespan even in the setting of serial stress pathway induction. In contrast, reducing stress granule formation in models of ataxia, amyotrophic lateral sclerosis and frontotemporal dementia largely exacerbated disease phenotypes. These data support a model whereby stress granules mitigate, rather than promote, neurodegenerative cascades.
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Affiliation(s)
- M Rebecca Glineburg
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 1 University Drive, Orange, CA 92866, USA
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Evrim Yildirim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Nicolas Gomez
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Cell and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Genesis Rodriguez
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Jaclyn Pak
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 1 University Drive, Orange, CA 92866, USA
| | - Xingli Li
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Christopher Altheim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Jacob Waksmacki
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Gerald M McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm 17165, Sweden
| | - Sami J Barmada
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Veterans Affairs Medical Center, Ann Arbor, MI, USA
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18
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Cortese A, Beecroft SJ, Facchini S, Curro R, Cabrera-Serrano M, Stevanovski I, Chintalaphani SR, Gamaarachchi H, Weisburd B, Folland C, Monahan G, Scriba CK, Dofash L, Johari M, Grosz BR, Ellis M, Fearnley LG, Tankard R, Read J, Merve A, Dominik N, Vegezzi E, Schnekenberg RP, Fernandez-Eulate G, Masingue M, Giovannini D, Delatycki MB, Storey E, Gardner M, Amor DJ, Nicholson G, Vucic S, Henderson RD, Robertson T, Dyke J, Fabian V, Mastaglia F, Davis MR, Kennerson M, Quinlivan R, Hammans S, Tucci A, Bahlo M, McLean CA, Laing NG, Stojkovic T, Houlden H, Hanna MG, Deveson IW, Lockhart PJ, Lamont PJ, Fahey MC, Bugiardini E, Ravenscroft G. A CCG expansion in ABCD3 causes oculopharyngodistal myopathy in individuals of European ancestry. Nat Commun 2024; 15:6327. [PMID: 39068203 PMCID: PMC11283466 DOI: 10.1038/s41467-024-49950-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 06/25/2024] [Indexed: 07/30/2024] Open
Abstract
Oculopharyngodistal myopathy (OPDM) is an inherited myopathy manifesting with ptosis, dysphagia and distal weakness. Pathologically it is characterised by rimmed vacuoles and intranuclear inclusions on muscle biopsy. In recent years CGG • CCG repeat expansion in four different genes were identified in OPDM individuals in Asian populations. None of these have been found in affected individuals of non-Asian ancestry. In this study we describe the identification of CCG expansions in ABCD3, ranging from 118 to 694 repeats, in 35 affected individuals across eight unrelated OPDM families of European ancestry. ABCD3 transcript appears upregulated in fibroblasts and skeletal muscle from OPDM individuals, suggesting a potential role of over-expression of CCG repeat containing ABCD3 transcript in progressive skeletal muscle degeneration. The study provides further evidence of the role of non-coding repeat expansions in unsolved neuromuscular diseases and strengthens the association between the CGG • CCG repeat motif and a specific pattern of muscle weakness.
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Affiliation(s)
- Andrea Cortese
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.
| | - Sarah J Beecroft
- Pawsey Supercomputing Research Centre, Kensington, WA, Australia
| | - Stefano Facchini
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Riccardo Curro
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Macarena Cabrera-Serrano
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Department of Neurology and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Universidad de Sevilla/CSIC, Sevilla, 41013, Spain
| | - Igor Stevanovski
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Sydney, NSW, Australia
| | - Sanjog R Chintalaphani
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Sydney, NSW, Australia
| | - Hasindu Gamaarachchi
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Sydney, NSW, Australia
- School of Computer Science and Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Ben Weisburd
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Chiara Folland
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Gavin Monahan
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Carolin K Scriba
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
| | - Lein Dofash
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Mridul Johari
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Bianca R Grosz
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, 2139, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2006, Australia
| | - Melina Ellis
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, 2139, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2006, Australia
| | - Liam G Fearnley
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, 1 G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC3052, Australia
| | - Rick Tankard
- Department of Mathematics and Statistics, Curtin University, Perth, WA, Australia
| | - Justin Read
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, VIC, Australia
| | - Ashirwad Merve
- Department of Neuropathology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Natalia Dominik
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | | | - Ricardo P Schnekenberg
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Gorka Fernandez-Eulate
- Centre de Référence des Maladies Neuromusculaires Nord-Est-Ile de France, Hôpital Pitié-Salpêtrière, Institut de Myologie, APHP, Paris, France
| | - Marion Masingue
- Centre de Référence des Maladies Neuromusculaires Nord-Est-Ile de France, Hôpital Pitié-Salpêtrière, Institut de Myologie, APHP, Paris, France
| | - Diane Giovannini
- CHU Grenoble Alpes, Grenoble Institut Neurosciences, INSERM, U1216, Université Grenoble Alpes, Grenoble, France
| | - Martin B Delatycki
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, VIC, Australia
| | - Elsdon Storey
- Neurology Department, The Alfred Hospital, Melbourne, VIC, Australia
| | - Mac Gardner
- The Laboratory for Genomic Medicine, University of Otago, Dunedin, New Zealand
| | - David J Amor
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, VIC, Australia
| | - Garth Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, 2139, Australia
- Molecular Medicine Laboratory, Concord Repatriation General Hospital, Sydney, NSW, 2139, Australia
| | - Steve Vucic
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2006, Australia
- Brain and Nerve Research Centre, Concord Repatriation General Hospital, Sydney, NSW, 2139, Australia
| | - Robert D Henderson
- Department of Neurology, Royal Brisbane & Women's Hospital, Herston, QLD, Australia
- UQ Centre for Clinical Research, Herston, QLD, Australia
| | - Thomas Robertson
- Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
- School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD, Australia
| | - Jason Dyke
- PathWest Neuropathology, Royal Perth Hospital, Perth, WA, Australia
- School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia
| | - Vicki Fabian
- PathWest Neuropathology, Royal Perth Hospital, Perth, WA, Australia
| | - Frank Mastaglia
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
| | - Mark R Davis
- Neurogenetics Unit, Diagnostic Genomics, PathWest, Nedlands, WA, Australia
| | - Marina Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW, 2139, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2006, Australia
- Molecular Medicine Laboratory, Concord Repatriation General Hospital, Sydney, NSW, 2139, Australia
| | - Ros Quinlivan
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health & MRC Centre for Neuromuscular Diseases, London, United Kingdom
| | - Simon Hammans
- Wessex Neurological Centre, University Hospital Southampton, Southampton, United Kingdom
| | - Arianna Tucci
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, 1 G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC3052, Australia
| | - Catriona A McLean
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
- Department of Anatomical Pathology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Nigel G Laing
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Tanya Stojkovic
- Centre de Référence des Maladies Neuromusculaires Nord-Est-Ile de France, Hôpital Pitié-Salpêtrière, Institut de Myologie, APHP, Paris, France
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Ira W Deveson
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Sydney, NSW, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, VIC, Australia
| | | | - Michael C Fahey
- Department of Paediatrics Monash Children's Hospital, Victoria, Australia
| | - Enrico Bugiardini
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Gianina Ravenscroft
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
- Centre for Medical Research, University of Western Australia, Nedlands, WA, Australia.
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19
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Klusek J, Will E, Christensen T, Caravella K, Hogan A, Sun J, Smith J, Fairchild AJ, Roberts JE. Social Communication Delay in an Unbiased Sample of Preschoolers With the FMR1 Premutation. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2024; 67:2316-2332. [PMID: 38889222 PMCID: PMC11253810 DOI: 10.1044/2024_jslhr-23-00580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/20/2023] [Accepted: 04/15/2024] [Indexed: 06/20/2024]
Abstract
PURPOSE The Fragile X Messenger Ribonucleoprotein-1 (FMR1) premutation (FXpm) is a genetic variant that is common in the general population and is associated with health symptoms and disease in adulthood. However, poor understanding of the clinical phenotype during childhood has hindered the development of clinical practice guidelines for screening and intervention. Given that social communication difficulties have been widely documented in adults with the FXpm and are linked with reduced psychosocial functioning, the present study aimed to characterize the communication profile of the FXpm during early childhood. METHOD Eighteen children with the FXpm who were identified through cascade testing (89%) or screening at birth (11%) were compared to 21 matched typically developing children, aged 2-4 years. Participants completed standardized assessments of language (Mullen Scales of Early Learning) and adaptive communication (Vineland Adaptive Behavior Scales-II). Social communication was rated from seminaturalistic interaction samples using the Brief Observation of Social Communication Change. RESULTS Children with the FXpm showed delayed social communication development, with the magnitude of group differences highlighting social communication as a feature that distinguishes children with the FXpm from their peers (p = .046, ηp2 = .12). The groups did not differ on the standardized language and adaptive communication measures (ps > .297, ηp2s < .03). CONCLUSIONS Early screening and treatment of social communication delays may be key to optimizing outcomes for children with the FXpm. Further research is needed to replicate findings in a larger sample, delineate the trajectory and consequences of social communication difficulties across the life span in the FXpm, and determine the potential epidemiological significance of FMR1 as a mediator of developmental communication differences within the general population.
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Affiliation(s)
- Jessica Klusek
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia
| | - Elizabeth Will
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia
| | - Thomas Christensen
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia
| | - Kelly Caravella
- Department of Psychiatry, Carolina Institute for Developmental Disabilities, The University of North Carolina at Chapel Hill School of Medicine
| | - Abigail Hogan
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia
| | - Jennifer Sun
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia
| | - Jenna Smith
- Department of Psychology, University of South Carolina, Columbia
| | | | - Jane E. Roberts
- Department of Psychology, University of South Carolina, Columbia
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20
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Sirois CL, Guo Y, Li M, Wolkoff NE, Korabelnikov T, Sandoval S, Lee J, Shen M, Contractor A, Sousa AMM, Bhattacharyya A, Zhao X. CGG repeats in the human FMR1 gene regulate mRNA localization and cellular stress in developing neurons. Cell Rep 2024; 43:114330. [PMID: 38865241 PMCID: PMC11240841 DOI: 10.1016/j.celrep.2024.114330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 04/18/2024] [Accepted: 05/22/2024] [Indexed: 06/14/2024] Open
Abstract
The human genome has many short tandem repeats, yet the normal functions of these repeats are unclear. The 5' untranslated region (UTR) of the fragile X messenger ribonucleoprotein 1 (FMR1) gene contains polymorphic CGG repeats, the length of which has differing effects on FMR1 expression and human health, including the neurodevelopmental disorder fragile X syndrome. We deleted the CGG repeats in the FMR1 gene (0CGG) in human stem cells and examined the effects on differentiated neurons. 0CGG neurons have altered subcellular localization of FMR1 mRNA and protein, and differential expression of cellular stress proteins compared with neurons with normal repeats (31CGG). In addition, 0CGG neurons have altered responses to glucocorticoid receptor (GR) activation, including FMR1 mRNA localization, GR chaperone HSP90α expression, GR localization, and cellular stress protein levels. Therefore, the CGG repeats in the FMR1 gene are important for the homeostatic responses of neurons to stress signals.
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Affiliation(s)
- Carissa L Sirois
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Yu Guo
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Meng Li
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Natalie E Wolkoff
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tomer Korabelnikov
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Soraya Sandoval
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Jiyoun Lee
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Minjie Shen
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Amaya Contractor
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Andre M M Sousa
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Anita Bhattacharyya
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA.
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21
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Tseng YJ, Krans A, Malik I, Deng X, Yildirim E, Ovunc S, Tank EH, Jansen-West K, Kaufhold R, Gomez N, Sher R, Petrucelli L, Barmada S, Todd P. Ribosomal quality control factors inhibit repeat-associated non-AUG translation from GC-rich repeats. Nucleic Acids Res 2024; 52:5928-5949. [PMID: 38412259 PMCID: PMC11162809 DOI: 10.1093/nar/gkae137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 02/05/2024] [Accepted: 02/19/2024] [Indexed: 02/29/2024] Open
Abstract
A GGGGCC (G4C2) hexanucleotide repeat expansion in C9ORF72 causes amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD), while a CGG trinucleotide repeat expansion in FMR1 leads to the neurodegenerative disorder Fragile X-associated tremor/ataxia syndrome (FXTAS). These GC-rich repeats form RNA secondary structures that support repeat-associated non-AUG (RAN) translation of toxic proteins that contribute to disease pathogenesis. Here we assessed whether these same repeats might trigger stalling and interfere with translational elongation. We find that depletion of ribosome-associated quality control (RQC) factors NEMF, LTN1 and ANKZF1 markedly boost RAN translation product accumulation from both G4C2 and CGG repeats while overexpression of these factors reduces RAN production in both reporter assays and C9ALS/FTD patient iPSC-derived neurons. We also detected partially made products from both G4C2 and CGG repeats whose abundance increased with RQC factor depletion. Repeat RNA sequence, rather than amino acid content, is central to the impact of RQC factor depletion on RAN translation-suggesting a role for RNA secondary structure in these processes. Together, these findings suggest that ribosomal stalling and RQC pathway activation during RAN translation inhibits the generation of toxic RAN products. We propose augmenting RQC activity as a therapeutic strategy in GC-rich repeat expansion disorders.
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Affiliation(s)
- Yi-Ju Tseng
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48109, USA
| | - Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502284 Telangana, India
| | - Xiexiong Deng
- Department of Molecular, Cellular and Developmental Biology, Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Evrim Yildirim
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sinem Ovunc
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Elizabeth M H Tank
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Karen Jansen-West
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Ross Kaufhold
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicolas B Gomez
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roger Sher
- Department of Neurobiology and Behavior & Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48109, USA
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22
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Charlet-Berguerand N. An unexpected polyglycine route to spinocerebellar ataxia. Nat Genet 2024; 56:1039-1041. [PMID: 38811843 DOI: 10.1038/s41588-024-01770-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Affiliation(s)
- Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U-1258, CNRS UMR-7104, University of Strasbourg, Illkirch, France.
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23
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Kumar M, Sahni S, A V, Kumar D, Kushwah N, Goel D, Kapoor H, Srivastava AK, Faruq M. Molecular clues unveiling spinocerebellar ataxia type-12 pathogenesis. iScience 2024; 27:109768. [PMID: 38711441 PMCID: PMC11070597 DOI: 10.1016/j.isci.2024.109768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/31/2024] [Accepted: 04/15/2024] [Indexed: 05/08/2024] Open
Abstract
Spinocerebellar Ataxia type-12 (SCA12) is a neurodegenerative disease caused by tandem CAG repeat expansion in the 5'-UTR/non-coding region of PPP2R2B. Molecular pathology of SCA12 has not been studied in the context of CAG repeats, and no appropriate models exist. We found in human SCA12-iPSC-derived neuronal lineage that expanded CAG in PPP2R2B transcript forms nuclear RNA foci and were found to sequester variety of proteins. Further, the ectopic expression of transcript containing varying length of CAG repeats exhibits non-canonical repeat-associated non-AUG (RAN) translation in multiple frames in HEK293T cells, which was further validated in patient-derived neural stem cells using specific antibodies. mRNA sequencing of the SCA12 and control neurons have shown a network of crucial transcription factors affecting neural fate, in addition to alteration of various signaling pathways involved in neurodevelopment. Altogether, this study identifies the molecular signatures of SCA12 disorder using patient-derived neuronal cell lines.
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Affiliation(s)
- Manish Kumar
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- CSIR-HRDC Campus, Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shweta Sahni
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- Department of Neurology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Vivekanand A
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- CSIR-HRDC Campus, Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Deepak Kumar
- Division of Genomics and Molecular Medicine, CSIR - Institute of Genomics and Integrative Biology (IGIB), New Delhi 110007, India
- Department of Zoology, University of Allahabad, Prayagraj, Uttar Pradesh 211002, India
| | - Neetu Kushwah
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
| | - Divya Goel
- Department of Pharmacology, School of Pharmaceutical Education & Research (SPER), Jamia Hamdard, New Delhi 110062, India
| | - Himanshi Kapoor
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
| | - Achal K. Srivastava
- Department of Neurology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- CSIR-HRDC Campus, Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
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24
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Kudo K, Hori K, Asamitsu S, Maeda K, Aida Y, Hokimoto M, Matsuo K, Yabuki Y, Shioda N. Structural polymorphism of the nucleic acids in pentanucleotide repeats associated with the neurological disorder CANVAS. J Biol Chem 2024; 300:107138. [PMID: 38447794 PMCID: PMC10999818 DOI: 10.1016/j.jbc.2024.107138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 02/15/2024] [Accepted: 02/27/2024] [Indexed: 03/08/2024] Open
Abstract
Short tandem repeats are inherently unstable during DNA replication depending on repeat length, and the expansion of the repeat length in the human genome is responsible for repeat expansion disorders. Pentanucleotide AAGGG and ACAGG repeat expansions in intron 2 of the gene encoding replication factor C subunit 1 (RFC1) cause cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) and other phenotypes of late-onset cerebellar ataxia. Herein, we reveal the structural polymorphism of the RFC1 repeats associated with CANVAS in vitro. Single-stranded AAGGG repeat DNA formed a hybrid-type G-quadruplex, whereas its RNA formed a parallel-type G-quadruplex with three layers. The RNA of the ACAGG repeat formed hairpin structure comprising C-G and G-C base pairs with A:A and GA:AG mismatched repeats. Furthermore, both pathogenic repeat RNAs formed more rigid structures than those of the nonpathogenic repeat RNAs. These findings provide novel insights into the structural polymorphism of the RFC1 repeats, which may be closely related to the disease mechanism of CANVAS.
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Affiliation(s)
- Kenta Kudo
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan; Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Karin Hori
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
| | - Sefan Asamitsu
- Laboratory for Functional Non-coding Genomics, RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan
| | - Kohei Maeda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan; Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yukari Aida
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan; Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Mei Hokimoto
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan; Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazuya Matsuo
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
| | - Yasushi Yabuki
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan; Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Norifumi Shioda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan; Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
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25
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Westover KR, Jin P, Yao B. Bridging the gap: R-loop mediated genomic instability and its implications in neurological diseases. Epigenomics 2024; 16:589-608. [PMID: 38530068 PMCID: PMC11160457 DOI: 10.2217/epi-2023-0379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/12/2024] [Indexed: 03/27/2024] Open
Abstract
R-loops, intricate three-stranded structures formed by RNA-DNA hybrids and an exposed non-template DNA strand, are fundamental to various biological phenomena. They carry out essential and contrasting functions within cellular mechanisms, underlining their critical role in maintaining cellular homeostasis. The specific cellular context that dictates R-loop formation determines their function, particularly emphasizing the necessity for their meticulous genomic regulation. Notably, the aberrant formation or misregulation of R-loops is implicated in numerous neurological disorders. This review focuses on the complex interactions between R-loops and double-strand DNA breaks, exploring how R-loop dysregulation potentially contributes to the pathogenesis of various brain disorders, which could provide novel insights into the molecular mechanisms underpinning neurological disease progression and identify potential therapeutic targets by highlighting these aspects.
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Affiliation(s)
- Katherine R Westover
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
| | - Bing Yao
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
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26
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Tak Y, Schneider A, Santos E, Randol JL, Tassone F, Hagerman P, Hagerman RJ. Unmethylated Mosaic Full Mutation Males without Fragile X Syndrome. Genes (Basel) 2024; 15:331. [PMID: 38540390 PMCID: PMC10970065 DOI: 10.3390/genes15030331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/26/2024] [Accepted: 02/28/2024] [Indexed: 04/07/2024] Open
Abstract
Fragile X syndrome (FXS) is the leading inherited cause of intellectual disability (ID) and single gene cause of autism. Although most patients with FXS and the full mutation (FM) have complete methylation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene, some have mosaicism in methylation and/or CGG repeat size, and few have completely unmethylated FM alleles. Those with a complete lack of methylation are rare, with little literature about the cognitive and behavioral phenotypes of these individuals. A review of past literature was conducted regarding individuals with unmethylated and mosaic FMR1 FM. We report three patients with an unmethylated FM FMR1 alleles without any behavioral or cognitive deficits. This is an unusual presentation for men with FM as most patients with an unmethylated FM and no behavioral phenotypes do not receive fragile X DNA testing or a diagnosis of FXS. Our cases showed that mosaic males with unmethylated FMR1 FM alleles may lack behavioral phenotypes due to the presence of smaller alleles producing the FMR1 protein (FMRP). However, these individuals could be at a higher risk of developing fragile X-associated tremor/ataxia syndrome (FXTAS) due to the increased expression of mRNA, similar to those who only have a premutation.
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Affiliation(s)
- YeEun Tak
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA 95616, USA; (Y.T.); (E.S.); (F.T.); (P.H.)
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
| | - Andrea Schneider
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
| | - Ellery Santos
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA 95616, USA; (Y.T.); (E.S.); (F.T.); (P.H.)
| | - Jamie Leah Randol
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
| | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA 95616, USA; (Y.T.); (E.S.); (F.T.); (P.H.)
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
| | - Paul Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA 95616, USA; (Y.T.); (E.S.); (F.T.); (P.H.)
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
| | - Randi J. Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA 95616, USA; (Y.T.); (E.S.); (F.T.); (P.H.)
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
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27
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Dufour BD, Bartley T, McBride E, Allen E, McLennan YA, Hagerman RJ, Martínez-Cerdeño V. FXTAS Neuropathology Includes Widespread Reactive Astrogliosis and White Matter Specific Astrocyte Degeneration. Ann Neurol 2024; 95:558-575. [PMID: 38069470 PMCID: PMC10922917 DOI: 10.1002/ana.26851] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 01/17/2024]
Abstract
OBJECTIVE Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset progressive genetic neurodegenerative disorder that occurs in FMR1 premutation carriers. The temporal, spatial, and cell-type specific patterns of neurodegeneration in the FXTAS brain remain incompletely characterized. Intranuclear inclusion bodies are the neuropathological hallmark of FXTAS, which are largest and occur most frequently in astrocytes, glial cells that maintain brain homeostasis. Here, we characterized neuropathological alterations in astrocytes in multiple regions of the FXTAS brain. METHODS Striatal and cerebellar sections from FXTAS cases (n = 12) and controls (n = 12) were stained for the astrocyte markers glial fibrillary acidic protein (GFAP) and aldehyde dehydrogenase 1L1 (ALDH1L1) using immunohistochemistry. Reactive astrogliosis severity, the prevalence of GFAP+ fragments, and astrocyte density were scored. Double label immunofluorescence was utilized to detect co-localization of GFAP and cleaved caspase-3. RESULTS FXTAS cases showed widespread reactive gliosis in both grey and white matter. GFAP staining also revealed remarkably severe astrocyte pathology in FXTAS white matter - characterized by a significant and visible reduction in astrocyte density (-38.7% in striatum and - 32.2% in cerebellum) and the widespread presence of GFAP+ fragments reminiscent of apoptotic bodies. White matter specific reductions in astrocyte density were confirmed with ALDH1L1 staining. GFAP+ astrocytes and fragments in white matter were positive for cleaved caspase-3, suggesting that apoptosis-mediated degeneration is responsible for reduced astrocyte counts. INTERPRETATION We have established that FXTAS neuropathology includes robust degeneration of astrocytes, which is specific to white matter. Because astrocytes are essential for maintaining homeostasis within the central nervous system, a loss of astrocytes likely further exacerbates neuropathological progression of other cell types in the FXTAS brain. ANN NEUROL 2024;95:558-575.
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Affiliation(s)
- Brett D. Dufour
- Department of Psychiatry & Behavioral Sciences, UC Davis School of Medicine, Sacramento, CA, USA
- Institute for Pediatric Regenerative Medicine (IPRM), Shriner’s Hospital for Children and UC Davis School of Medicine, Sacramento, CA, USA
- Department of Pathology & Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
- MIND Institute, UC Davis School of Medicine, Sacramento, CA, USA
| | - Trevor Bartley
- Institute for Pediatric Regenerative Medicine (IPRM), Shriner’s Hospital for Children and UC Davis School of Medicine, Sacramento, CA, USA
- Department of Pathology & Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
| | - Erin McBride
- Institute for Pediatric Regenerative Medicine (IPRM), Shriner’s Hospital for Children and UC Davis School of Medicine, Sacramento, CA, USA
- Department of Pathology & Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
| | - Erik Allen
- Institute for Pediatric Regenerative Medicine (IPRM), Shriner’s Hospital for Children and UC Davis School of Medicine, Sacramento, CA, USA
- Department of Pathology & Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
| | - Yingratana A. McLennan
- Institute for Pediatric Regenerative Medicine (IPRM), Shriner’s Hospital for Children and UC Davis School of Medicine, Sacramento, CA, USA
- Department of Pathology & Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
| | - Randi J. Hagerman
- MIND Institute, UC Davis School of Medicine, Sacramento, CA, USA
- Department of Pediatrics, UC Davis School of Medicine, Sacramento, CA, USA
| | - Verónica Martínez-Cerdeño
- Institute for Pediatric Regenerative Medicine (IPRM), Shriner’s Hospital for Children and UC Davis School of Medicine, Sacramento, CA, USA
- Department of Pathology & Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
- MIND Institute, UC Davis School of Medicine, Sacramento, CA, USA
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Shi Y, Cao C, Zeng Y, Ding Y, Chen L, Zheng F, Chen X, Zhou F, Yang X, Li J, Xu L, Xu G, Lin M, Ishiura H, Tsuji S, Wang N, Wang Z, Chen WJ, Yang K. CGG repeat expansion in LOC642361/NUTM2B-AS1 typically presents as oculopharyngodistal myopathy. J Genet Genomics 2024; 51:184-196. [PMID: 38159879 DOI: 10.1016/j.jgg.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/25/2023] [Accepted: 12/25/2023] [Indexed: 01/03/2024]
Abstract
CGG repeat expansions in LOC642361/NUTM2B-AS1 have recently been identified as a cause of oculopharyngeal myopathy with leukoencephalopathy. However, since only three patients from a single family were reported, it remains unknown whether their clinicopathological features are typical for CGG repeat expansions in LOC642361/NUTM2B-AS1. Here, using repeat-primed-polymerase chain reaction and long-read sequencing, we identify 12 individuals from 3 unrelated families with CGG repeat expansions in LOC642361/NUTM2B-AS1, typically presenting with oculopharyngodistal myopathy. The CGG repeat expansions range from 161 to 669 repeat units. Most of the patients present with ptosis, restricted eye movements, dysphagia, dysarthria, and diffuse limb muscle weakness. Only one patient shows T2-weighted hyperintensity in the cerebellar white matter surrounding the deep cerebellar nuclei on brain magnetic resonance imaging. Muscle biopsies from three patients show a myopathic pattern and rimmed vacuoles. Analyses of muscle biopsies suggest that CGG repeat expansions in LOC642361/NUTM2B-AS1 may deleteriously affect aggrephagic capacity, suggesting that RNA toxicity and mitochondrial dysfunction may contribute to pathogenesis. Our study thus expands the phenotypic spectrum for the CGG repeat expansion of LOC642361/NUTM2B-AS1 and indicates that this genetic variant typically manifests as oculopharyngodistal myopathy with chronic myopathic changes with rimmed vacuoles and filamentous intranuclear inclusions in muscle fibers.
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Affiliation(s)
- Yan Shi
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Chunyan Cao
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; The First Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471000, China
| | - Yiheng Zeng
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Yuanliang Ding
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Long Chen
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Fuze Zheng
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Xuejiao Chen
- Department of Neurology, Zhangzhou Municipal Hospital of Fujian Province and Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, Fujian 363000, China
| | - Fanggui Zhou
- Department of Neurology, Jian'ou Municipal Hospital of Fujian Province, Jian'ou, Fujian 353100, China
| | - Xiefeng Yang
- Department of Radiology, First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Jinjing Li
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Liuqing Xu
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Guorong Xu
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Minting Lin
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Hiroyuki Ishiura
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; Department of Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
| | - Shoji Tsuji
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; Institute of Medical Genomics, International University of Health and Welfare, Chiba 286-0048, Japan
| | - Ning Wang
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China
| | - Zhiqiang Wang
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China.
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China.
| | - Kang Yang
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China; Department of Neurology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350212, China.
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Nakamori M. Expanded‐repeat‐RNA‐mediated disease mechanisms in myotonic dystrophy. NEUROLOGY AND CLINICAL NEUROSCIENCE 2024; 12:16-23. [DOI: 10.1111/ncn3.12687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 12/05/2022] [Indexed: 01/04/2025]
Abstract
AbstractMyotonic dystrophy (DM) is the most common muscular dystrophy in adults, affecting skeletal muscle as well as cardiac and smooth muscle. Furthermore, involvement of the central nervous system, endocrine organs, and eyes is often seen, with debilitating consequences. The condition is an autosomal‐dominant inherited genetic disease caused by abnormal genomic expansion of tandem repeats. Myotonic dystrophy type 1 (DM1) results from expansion of a CTG repeat in the 3′‐untranslated region of the gene encoding dystrophia myotonica‐protein kinase (DMPK), whereas myotonic dystrophy type 2 (DM2) is caused by expansion of a CCTG repeat in the first intron of the gene encoding CCHC‐type zinc finger nucleic acid‐binding protein (CNBP). Both types of DM exhibit abnormal mRNA transcribed from the mutated gene containing expanded repeats, which exert toxic gain‐of‐function effects on various proteins involved in cellular processes such as alternative splicing, signaling pathways, and cellular senescence. The present review discusses the expanded‐repeat‐RNA‐mediated molecular pathomechanisms in DM.
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Affiliation(s)
- Masayuki Nakamori
- Department of Neurology Osaka University Graduate School of Medicine Osaka Japan
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30
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Malachowski T, Chandradoss KR, Boya R, Zhou L, Cook AL, Su C, Pham K, Haws SA, Kim JH, Ryu HS, Ge C, Luppino JM, Nguyen SC, Titus KR, Gong W, Wallace O, Joyce EF, Wu H, Rojas LA, Phillips-Cremins JE. Spatially coordinated heterochromatinization of long synaptic genes in fragile X syndrome. Cell 2023; 186:5840-5858.e36. [PMID: 38134876 PMCID: PMC10794044 DOI: 10.1016/j.cell.2023.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 07/31/2023] [Accepted: 11/16/2023] [Indexed: 12/24/2023]
Abstract
Short tandem repeat (STR) instability causes transcriptional silencing in several repeat expansion disorders. In fragile X syndrome (FXS), mutation-length expansion of a CGG STR represses FMR1 via local DNA methylation. Here, we find megabase-scale H3K9me3 domains on autosomes and encompassing FMR1 on the X chromosome in FXS patient-derived iPSCs, iPSC-derived neural progenitors, EBV-transformed lymphoblasts, and brain tissue with mutation-length CGG expansion. H3K9me3 domains connect via inter-chromosomal interactions and demarcate severe misfolding of TADs and loops. They harbor long synaptic genes replicating at the end of S phase, replication-stress-induced double-strand breaks, and STRs prone to stepwise somatic instability. CRISPR engineering of the mutation-length CGG to premutation length reverses H3K9me3 on the X chromosome and multiple autosomes, refolds TADs, and restores gene expression. H3K9me3 domains can also arise in normal-length iPSCs created with perturbations linked to genome instability, suggesting their relevance beyond FXS. Our results reveal Mb-scale heterochromatinization and trans interactions among loci susceptible to instability.
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Affiliation(s)
- Thomas Malachowski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Keerthivasan Raanin Chandradoss
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi Boya
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Linda Zhou
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ashley L Cook
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chuanbin Su
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Kenneth Pham
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Spencer A Haws
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ji Hun Kim
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Han-Seul Ryu
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chunmin Ge
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer M Luppino
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Son C Nguyen
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Katelyn R Titus
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Wanfeng Gong
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Owen Wallace
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | - Eric F Joyce
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Hao Wu
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | | | - Jennifer E Phillips-Cremins
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
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31
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Ito H, Machida K, Hasumi M, Ueyama M, Nagai Y, Imataka H, Taguchi H. Reconstitution of C9orf72 GGGGCC repeat-associated non-AUG translation with purified human translation factors. Sci Rep 2023; 13:22826. [PMID: 38129650 PMCID: PMC10739749 DOI: 10.1038/s41598-023-50188-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 12/16/2023] [Indexed: 12/23/2023] Open
Abstract
Nucleotide repeat expansion of GGGGCC (G4C2) in the non-coding region of C9orf72 is the most common genetic cause underlying amyotrophic lateral sclerosis and frontotemporal dementia. Transcripts harboring this repeat expansion undergo the translation of dipeptide repeats via a non-canonical process known as repeat-associated non-AUG (RAN) translation. In order to ascertain the essential components required for RAN translation, we successfully recapitulated G4C2-RAN translation using an in vitro reconstituted translation system comprising human factors, namely the human PURE system. Our findings conclusively demonstrate that the presence of fundamental translation factors is sufficient to mediate the elongation from the G4C2 repeat. Furthermore, the initiation mechanism proceeded in a 5' cap-dependent manner, independent of eIF2A or eIF2D. In contrast to cell lysate-mediated RAN translation, where longer G4C2 repeats enhanced translation, we discovered that the expansion of the G4C2 repeats inhibited translation elongation using the human PURE system. These results suggest that the repeat RNA itself functions as a repressor of RAN translation. Taken together, our utilization of a reconstituted RAN translation system employing minimal factors represents a distinctive and potent approach for elucidating the intricacies underlying RAN translation mechanism.
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Grants
- JPMJFS2112 Japan Science and Technology Agency
- JP26116002 Ministry of Education, Culture, Sports, Science and Technology
- JP18H03984 Ministry of Education, Culture, Sports, Science and Technology
- JP21H04763 Ministry of Education, Culture, Sports, Science and Technology
- JP20H05925 Ministry of Education, Culture, Sports, Science and Technology
- 2019-25 Mitsubishi Foundation
- 2019 Uehara Memorial Foundation
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Affiliation(s)
- Hayato Ito
- School of Life Science and Technology, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan
| | - Kodai Machida
- Graduate School of Engineering, University of Hyogo, Shosha, 2167, Himeji, Hyogo, 671-2280, Japan
| | - Mayuka Hasumi
- School of Life Science and Technology, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan
| | - Morio Ueyama
- Department of Neurology, Faculty of Medicine, Kindai University, Ohonohigashi 377-2, Osaka-Sayama, 589-8511, Japan
| | - Yoshitaka Nagai
- Department of Neurology, Faculty of Medicine, Kindai University, Ohonohigashi 377-2, Osaka-Sayama, 589-8511, Japan
| | - Hiroaki Imataka
- Graduate School of Engineering, University of Hyogo, Shosha, 2167, Himeji, Hyogo, 671-2280, Japan
| | - Hideki Taguchi
- School of Life Science and Technology, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan.
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan.
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32
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Persico T, Tranquillo ML, Seracchioli R, Zuccarello D, Sorrentino U. PGT-M for Premature Ovarian Failure Related to CGG Repeat Expansion of the FMR1 Gene. Genes (Basel) 2023; 15:6. [PMID: 38275588 PMCID: PMC10815814 DOI: 10.3390/genes15010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 01/27/2024] Open
Abstract
Primary ovarian failure (POF) is caused by follicle exhaustion and is associated with menstrual irregularities and elevated gonadotropin levels, which lead to infertility before the age of 40 years. The etiology of POI is mostly unknown, but a heterogeneous genetic and familial background can be identified in a subset of cases. Abnormalities in the fragile X mental retardation 1 gene (FMR1) are among the most prevalent monogenic causes of POI. These abnormalities are caused by the expansion of an unstable CGG repeat in the 5' untranslated region of FMR1. Expansions over 200 repeats cause fragile X syndrome (FXS), whereas expansions between 55 and 200 CGG repeats, which are defined as a fragile X premutation, have been associated with premature ovarian failure type 1 (POF1) in heterozygous females. Preimplantation genetic testing for monogenic diseases (PGT-M) can be proposed when the female carries a premutation or a full mutation. In this narrative review, we aim to recapitulate the clinical and molecular features of POF1 and their implications in the context of PGT-M.
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Affiliation(s)
- Tiziana Persico
- Medically Assisted Procreation Center, Maternal and Child Department, Beauregard Hospital, Valle D’Aosta Local Public Health, 11100 Aoste, Italy
| | - Maria Lucrezia Tranquillo
- Department of Medical and Surgical Sciences, University of Bologna, 40126 Bologna, Italy; (M.L.T.); (R.S.)
| | - Renato Seracchioli
- Department of Medical and Surgical Sciences, University of Bologna, 40126 Bologna, Italy; (M.L.T.); (R.S.)
- Division of Gynaecology and Human Reproduction Physiopathology, IRCCS Azienda Ospedaliero, University of Bologna, 40138 Bologna, Italy
| | - Daniela Zuccarello
- Clinical Genetics and Epidemiology Unit, University of Padova, 35128 Padova, Italy; (D.Z.); (U.S.)
| | - Ugo Sorrentino
- Clinical Genetics and Epidemiology Unit, University of Padova, 35128 Padova, Italy; (D.Z.); (U.S.)
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Kumar M, Tyagi N, Faruq M. The molecular mechanisms of spinocerebellar ataxias for DNA repeat expansion in disease. Emerg Top Life Sci 2023; 7:289-312. [PMID: 37668011 DOI: 10.1042/etls20230013] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/01/2023] [Accepted: 08/16/2023] [Indexed: 09/06/2023]
Abstract
Spinocerebellar ataxias (SCAs) are a heterogenous group of neurodegenerative disorders which commonly inherited in an autosomal dominant manner. They cause muscle incoordination due to degeneration of the cerebellum and other parts of nervous system. Out of all the characterized (>50) SCAs, 14 SCAs are caused due to microsatellite repeat expansion mutations. Repeat expansions can result in toxic protein gain-of-function, protein loss-of-function, and/or RNA gain-of-function effects. The location and the nature of mutation modulate the underlying disease pathophysiology resulting in varying disease manifestations. Potential toxic effects of these mutations likely affect key major cellular processes such as transcriptional regulation, mitochondrial functioning, ion channel dysfunction and synaptic transmission. Involvement of several common pathways suggests interlinked function of genes implicated in the disease pathogenesis. A better understanding of the shared and distinct molecular pathogenic mechanisms in these diseases is required to develop targeted therapeutic tools and interventions for disease management. The prime focus of this review is to elaborate on how expanded 'CAG' repeats contribute to the common modes of neurotoxicity and their possible therapeutic targets in management of such devastating disorders.
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Affiliation(s)
- Manish Kumar
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
| | - Nishu Tyagi
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
| | - Mohammed Faruq
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
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Kargar M, Hagerman RJ, Martínez-Cerdeño V. Neurodegeneration of White and Gray Matter in the Hippocampus with FXTAS. Int J Mol Sci 2023; 24:17266. [PMID: 38139097 PMCID: PMC10743470 DOI: 10.3390/ijms242417266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/07/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder that affects older premutation carriers (55-200 CGG repeats) of the fragile X gene. Despite the high prevalence of the FXTAS disorder, neuropathology studies of individuals affected by FXTAS are limited. We performed hematoxylin and eosin (H&E) staining in the hippocampus of 26 FXTAS cases and analyzed the tissue microscopically. The major neuropathological characteristics were white matter disease, intranuclear inclusions in neurons and astrocytes, and neuron loss. Astrocytes contained more and larger inclusions than neurons. There was a negative correlation between age of death and CGG repeat length in cases over the age of 60. The number of astroglial inclusions (CA3 and dentate gyrus) and the number of CA3 neuronal inclusions increased with elevated CGG repeat length. In the two cases with a CGG repeat size less than 65, FXTAS intranuclear inclusions were not present in the hippocampus, while in the two cases with less than 70 (65-70) CGG repeat expansion, neurons and astrocytes with inclusions were occasionally identified in the CA1 sub-region. These findings add hippocampus neuropathology to the previously reported changes in other areas of the brain in FXTAS patients, with implications for understanding FXTAS pathogenesis.
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Affiliation(s)
- Maryam Kargar
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, USA
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA
| | - Randi J. Hagerman
- MIND Institute, UC Davis School of Medicine, Sacramento, CA 95817, USA;
| | - Verónica Martínez-Cerdeño
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, USA
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA
- MIND Institute, UC Davis School of Medicine, Sacramento, CA 95817, USA;
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35
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Yang S, Wijegunawardana D, Sheth U, Veire AM, Salgado JMS, Agrawal M, Zhou J, Pereira JD, Gendron TF, Guo JU. Aberrant splicing exonizes C9ORF72 repeat expansion in ALS/FTD. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566896. [PMID: 38014069 PMCID: PMC10680656 DOI: 10.1101/2023.11.13.566896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
A nucleotide repeat expansion (NRE) in the first annotated intron of the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). While C9 NRE-containing RNAs can be translated into several toxic dipeptide repeat proteins, how an intronic NRE can assess the translation machinery in the cytoplasm remains unclear. By capturing and sequencing NRE-containing RNAs from patient-derived cells, we found that C9 NRE was exonized by the usage of downstream 5' splice sites and exported from the nucleus in a variety of spliced mRNA isoforms. C9ORF72 aberrant splicing was substantially elevated in both C9 NRE+ motor neurons and human brain tissues. Furthermore, NREs above the pathological threshold were sufficient to activate cryptic splice sites in reporter mRNAs. In summary, our results revealed a crucial and potentially widespread role of repeat-induced aberrant splicing in the biogenesis, localization, and translation of NRE-containing RNAs.
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Affiliation(s)
- Suzhou Yang
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Denethi Wijegunawardana
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Udit Sheth
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences; Jacksonville, FL 32224, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Austin M. Veire
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences; Jacksonville, FL 32224, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Juliana M. S. Salgado
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Manasi Agrawal
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jeffrey Zhou
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - João D. Pereira
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tania F. Gendron
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences; Jacksonville, FL 32224, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Junjie U. Guo
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
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Tassone F, Protic D, Allen EG, Archibald AD, Baud A, Brown TW, Budimirovic DB, Cohen J, Dufour B, Eiges R, Elvassore N, Gabis LV, Grudzien SJ, Hall DA, Hessl D, Hogan A, Hunter JE, Jin P, Jiraanont P, Klusek J, Kooy RF, Kraan CM, Laterza C, Lee A, Lipworth K, Losh M, Loesch D, Lozano R, Mailick MR, Manolopoulos A, Martinez-Cerdeno V, McLennan Y, Miller RM, Montanaro FAM, Mosconi MW, Potter SN, Raspa M, Rivera SM, Shelly K, Todd PK, Tutak K, Wang JY, Wheeler A, Winarni TI, Zafarullah M, Hagerman RJ. Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation. Cells 2023; 12:2330. [PMID: 37759552 PMCID: PMC10529056 DOI: 10.3390/cells12182330] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/09/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
The premutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene is characterized by an expansion of the CGG trinucleotide repeats (55 to 200 CGGs) in the 5' untranslated region and increased levels of FMR1 mRNA. Molecular mechanisms leading to fragile X-premutation-associated conditions (FXPAC) include cotranscriptional R-loop formations, FMR1 mRNA toxicity through both RNA gelation into nuclear foci and sequestration of various CGG-repeat-binding proteins, and the repeat-associated non-AUG (RAN)-initiated translation of potentially toxic proteins. Such molecular mechanisms contribute to subsequent consequences, including mitochondrial dysfunction and neuronal death. Clinically, premutation carriers may exhibit a wide range of symptoms and phenotypes. Any of the problems associated with the premutation can appropriately be called FXPAC. Fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND) can fall under FXPAC. Understanding the molecular and clinical aspects of the premutation of the FMR1 gene is crucial for the accurate diagnosis, genetic counseling, and appropriate management of affected individuals and families. This paper summarizes all the known problems associated with the premutation and documents the presentations and discussions that occurred at the International Premutation Conference, which took place in New Zealand in 2023.
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Affiliation(s)
- Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
| | - Dragana Protic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia;
- Fragile X Clinic, Special Hospital for Cerebral Palsy and Developmental Neurology, 11040 Belgrade, Serbia
| | - Emily Graves Allen
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Alison D. Archibald
- Victorian Clinical Genetics Services, Royal Children’s Hospital, Melbourne, VIC 3052, Australia;
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia;
- Genomics in Society Group, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Anna Baud
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland; (A.B.); (K.T.)
| | - Ted W. Brown
- Central Clinical School, University of Sydney, Sydney, NSW 2006, Australia;
- Fragile X Association of Australia, Brookvale, NSW 2100, Australia;
- NYS Institute for Basic Research in Developmental Disabilities, New York, NY 10314, USA
| | - Dejan B. Budimirovic
- Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA;
- Department of Psychiatry & Behavioral Sciences-Child Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jonathan Cohen
- Fragile X Alliance Clinic, Melbourne, VIC 3161, Australia;
| | - Brett Dufour
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Rachel Eiges
- Stem Cell Research Laboratory, Medical Genetics Institute, Shaare Zedek Medical Center Affiliated with the Hebrew University School of Medicine, Jerusalem 91031, Israel;
| | - Nicola Elvassore
- Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy; (N.E.); (C.L.)
- Department of Industrial Engineering, University of Padova, 35131 Padova, Italy
| | - Lidia V. Gabis
- Keshet Autism Center Maccabi Wolfson, Holon 5822012, Israel;
- Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Samantha J. Grudzien
- Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA; (S.J.G.); (P.K.T.)
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Deborah A. Hall
- Department of Neurological Sciences, Rush University, Chicago, IL 60612, USA;
| | - David Hessl
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Abigail Hogan
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; (A.H.); (J.K.)
| | - Jessica Ezzell Hunter
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Poonnada Jiraanont
- Faculty of Medicine, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand;
| | - Jessica Klusek
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; (A.H.); (J.K.)
| | - R. Frank Kooy
- Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium;
| | - Claudine M. Kraan
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia;
- Diagnosis and Development, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
| | - Cecilia Laterza
- Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy; (N.E.); (C.L.)
- Department of Industrial Engineering, University of Padova, 35131 Padova, Italy
| | - Andrea Lee
- Fragile X New Zealand, Nelson 7040, New Zealand;
| | - Karen Lipworth
- Fragile X Association of Australia, Brookvale, NSW 2100, Australia;
| | - Molly Losh
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60201, USA;
| | - Danuta Loesch
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia;
| | - Reymundo Lozano
- Departments of Genetics and Genomic Sciences and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Marsha R. Mailick
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA;
| | - Apostolos Manolopoulos
- Intramural Research Program, Laboratory of Clinical Investigation, National Institute on Aging, Baltimore, MD 21224, USA;
| | - Veronica Martinez-Cerdeno
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Yingratana McLennan
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | | | - Federica Alice Maria Montanaro
- Child and Adolescent Neuropsychiatry Unit, Department of Neuroscience, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
- Department of Education, Psychology, Communication, University of Bari Aldo Moro, 70121 Bari, Italy
| | - Matthew W. Mosconi
- Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS 66045, USA;
- Clinical Child Psychology Program, University of Kansas, Lawrence, KS 66045, USA
- Kansas Center for Autism Research and Training (K-CART), University of Kansas, Lawrence, KS 66045, USA
| | - Sarah Nelson Potter
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Melissa Raspa
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Susan M. Rivera
- Department of Psychology, University of Maryland, College Park, MD 20742, USA;
| | - Katharine Shelly
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Peter K. Todd
- Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA; (S.J.G.); (P.K.T.)
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48105, USA
| | - Katarzyna Tutak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland; (A.B.); (K.T.)
| | - Jun Yi Wang
- Center for Mind and Brain, University of California Davis, Davis, CA 95618, USA;
| | - Anne Wheeler
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Tri Indah Winarni
- Center for Biomedical Research (CEBIOR), Faculty of Medicine, Universitas Diponegoro, Semarang 502754, Central Java, Indonesia;
| | - Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Randi J. Hagerman
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
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Wang S, Sun S. Translation dysregulation in neurodegenerative diseases: a focus on ALS. Mol Neurodegener 2023; 18:58. [PMID: 37626421 PMCID: PMC10464328 DOI: 10.1186/s13024-023-00642-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023] Open
Abstract
RNA translation is tightly controlled in eukaryotic cells to regulate gene expression and maintain proteome homeostasis. RNA binding proteins, translation factors, and cell signaling pathways all modulate the translation process. Defective translation is involved in multiple neurological diseases including amyotrophic lateral sclerosis (ALS). ALS is a progressive neurodegenerative disorder and poses a major public health challenge worldwide. Over the past few years, tremendous advances have been made in the understanding of the genetics and pathogenesis of ALS. Dysfunction of RNA metabolisms, including RNA translation, has been closely associated with ALS. Here, we first introduce the general mechanisms of translational regulation under physiological and stress conditions and review well-known examples of translation defects in neurodegenerative diseases. We then focus on ALS-linked genes and discuss the recent progress on how translation is affected by various mutant genes and the repeat expansion-mediated non-canonical translation in ALS.
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Affiliation(s)
- Shaopeng Wang
- Department of Physiology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Shuying Sun
- Department of Physiology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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38
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Giménez-Bejarano A, Alegre-Cortés E, Yakhine-Diop SMS, Gómez-Suaga P, Fuentes JM. Mitochondrial Dysfunction in Repeat Expansion Diseases. Antioxidants (Basel) 2023; 12:1593. [PMID: 37627588 PMCID: PMC10451345 DOI: 10.3390/antiox12081593] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/29/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Repeat expansion diseases are a group of neuromuscular and neurodegenerative disorders characterized by expansions of several successive repeated DNA sequences. Currently, more than 50 repeat expansion diseases have been described. These disorders involve diverse pathogenic mechanisms, including loss-of-function mechanisms, toxicity associated with repeat RNA, or repeat-associated non-ATG (RAN) products, resulting in impairments of cellular processes and damaged organelles. Mitochondria, double membrane organelles, play a crucial role in cell energy production, metabolic processes, calcium regulation, redox balance, and apoptosis regulation. Its dysfunction has been implicated in the pathogenesis of repeat expansion diseases. In this review, we provide an overview of the signaling pathways or proteins involved in mitochondrial functioning described in these disorders. The focus of this review will be on the analysis of published data related to three representative repeat expansion diseases: Huntington's disease, C9orf72-frontotemporal dementia/amyotrophic lateral sclerosis, and myotonic dystrophy type 1. We will discuss the common effects observed in all three repeat expansion disorders and their differences. Additionally, we will address the current gaps in knowledge and propose possible new lines of research. Importantly, this group of disorders exhibit alterations in mitochondrial dynamics and biogenesis, with specific proteins involved in these processes having been identified. Understanding the underlying mechanisms of mitochondrial alterations in these disorders can potentially lead to the development of neuroprotective strategies.
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Affiliation(s)
- Alberto Giménez-Bejarano
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Eva Alegre-Cortés
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Sokhna M. S. Yakhine-Diop
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Patricia Gómez-Suaga
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - José M. Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
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Malik I, Tseng YJ, Wieland CM, Green KM, Zheng K, Calleja K, Todd PK. Dissecting the roles of EIF4G homologs reveals DAP5 as a modifier of CGG repeat-associated toxicity in a Drosophila model of FXTAS. Neurobiol Dis 2023; 184:106212. [PMID: 37352983 PMCID: PMC11149892 DOI: 10.1016/j.nbd.2023.106212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 06/25/2023] Open
Abstract
Neurodegeneration in Fragile X-associated tremor/ataxia syndrome (FXTAS) is caused by a CGG trinucleotide repeat expansion in the 5' UTR of FMR1. Expanded CGG repeat RNAs form stable secondary structures, which in turn support repeat-associated non-AUG (RAN) translation to produce toxic peptides. The parameters that impact RAN translation initiation efficiency are not well understood. Here we used a Drosophila melanogaster model of FXTAS to evaluate the role of the eIF4G family of eukaryotic translation initiation factors (EIF4G1, EIF4GII and EIF4G2/DAP5) in modulating RAN translation and CGG repeat-associated toxicity. DAP5 knockdown robustly suppressed CGG repeat-associated toxicity and inhibited RAN translation. Furthermore, knockdown of initiation factors that preferentially associate with DAP5 (such as EIF2β, EIF3F and EIF3G) also selectively suppressed CGG repeat-induced eye degeneration. In mammalian cellular reporter assays, DAP5 knockdown exhibited modest and cell-type specific effects on RAN translation. Taken together, these data support a role for DAP5 in CGG repeat associated toxicity possibly through modulation of RAN translation.
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Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Yi-Ju Tseng
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Clare M Wieland
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Kristina Zheng
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Katyanne Calleja
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA.
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40
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Zhang S, Pei G, Li B, Li P, Lin Y. Abnormal phase separation of biomacromolecules in human diseases. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1133-1152. [PMID: 37475546 PMCID: PMC10423695 DOI: 10.3724/abbs.2023139] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
Membrane-less organelles (MLOs) formed through liquid-liquid phase separation (LLPS) are associated with numerous important biological functions, but the abnormal phase separation will also dysregulate the physiological processes. Emerging evidence points to the importance of LLPS in human health and diseases. Nevertheless, despite recent advancements, our knowledge of the molecular relationship between LLPS and diseases is frequently incomplete. In this review, we outline our current understanding about how aberrant LLPS affects developmental disorders, tandem repeat disorders, cancers and viral infection. We also examine disease mechanisms driven by aberrant condensates, and highlight potential treatment approaches. This study seeks to expand our understanding of LLPS by providing a valuable new paradigm for understanding phase separation and human disorders, as well as to further translate our current knowledge regarding LLPS into therapeutic discoveries.
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Affiliation(s)
- Songhao Zhang
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Gaofeng Pei
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Boya Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Pilong Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Yi Lin
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
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41
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Wang JY, Sonico GJ, Salcedo-Arellano MJ, Hagerman RJ, Martinez-Cerdeno V. A Postmortem MRI Study of Cerebrovascular Disease and Iron Content at End-Stage of Fragile X-Associated Tremor/Ataxia Syndrome. Cells 2023; 12:1898. [PMID: 37508562 PMCID: PMC10377990 DOI: 10.3390/cells12141898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/03/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Brain changes at the end-stage of fragile X-associated tremor/ataxia syndrome (FXTAS) are largely unknown due to mobility impairment. We conducted a postmortem MRI study of FXTAS to quantify cerebrovascular disease, brain atrophy and iron content, and examined their relationships using principal component analysis (PCA). Intracranial hemorrhage (ICH) was observed in 4/17 FXTAS cases, among which one was confirmed by histologic staining. Compared with seven control brains, FXTAS cases showed higher ratings of T2-hyperintensities (indicating cerebral small vessel disease) in the cerebellum, globus pallidus and frontoparietal white matter, and significant atrophy in the cerebellar white matter, red nucleus and dentate nucleus. PCA of FXTAS cases revealed negative associations of T2-hyperintensity ratings with anatomic volumes and iron content in the white matter, hippocampus and amygdala, that were independent from a highly correlated number of regions with ICH and iron content in subcortical nuclei. Post-hoc analysis confirmed PCA findings and further revealed increased iron content in the white matter, hippocampus and amygdala in FXTAS cases compared to controls, after adjusting for T2-hyperintensity ratings. These findings indicate that both ischemic and hemorrhagic brain damage may occur in FXTAS, with the former being marked by demyelination/iron depletion and atrophy, and the latter by ICH and iron accumulation in basal ganglia.
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Affiliation(s)
- Jun Yi Wang
- Center for Mind and Brain, University of California Davis, Davis, CA 95618, USA
| | - Gerard J. Sonico
- Imaging Research Center, University of California Davis, Sacramento, CA 95817, USA;
| | - Maria Jimena Salcedo-Arellano
- Department of Pathology and Laboratory Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
- MIND Institute, University of California Davis Health, Sacramento, CA 95817, USA;
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA 95817, USA
| | - Randi J. Hagerman
- MIND Institute, University of California Davis Health, Sacramento, CA 95817, USA;
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Veronica Martinez-Cerdeno
- Department of Pathology and Laboratory Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA;
- MIND Institute, University of California Davis Health, Sacramento, CA 95817, USA;
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA 95817, USA
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42
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Viera Ortiz AP, Cajka G, Olatunji OA, Mikytuck B, Shalem O, Lee EB. Impaired ribosome-associated quality control of C9orf72 arginine-rich dipeptide-repeat proteins. Brain 2023; 146:2897-2912. [PMID: 36516294 PMCID: PMC10316761 DOI: 10.1093/brain/awac479] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 11/05/2022] [Accepted: 12/06/2022] [Indexed: 12/15/2022] Open
Abstract
Protein quality control pathways have evolved to ensure the fidelity of protein synthesis and efficiently clear potentially toxic protein species. Defects in ribosome-associated quality control and its associated factors have been implicated in the accumulation of aberrant proteins and neurodegeneration. C9orf72 repeat-associated non-AUG translation has been suggested to involve inefficient translation elongation, lead to ribosomal pausing and activation of ribosome-associated quality control pathways. However, the role of the ribosome-associated quality control complex in the processing of proteins generated through this non-canonical translation is not well understood. Here we use reporter constructs containing the C9orf72-associated hexanucleotide repeat, ribosome-associated quality control complex deficient cell models and stain for ribosome-associated quality control markers in C9orf72-expansion carrier human tissue to understand its role in dipeptide-repeat protein pathology. Our studies show that canonical ribosome-associated quality control substrates products are efficiently cleared by the ribosome-associated quality control complex in mammalian cells. Furthermore, using stalling reporter constructs, we show that repeats associated with the C9orf72-expansion induce ribosomal stalling when arginine (R)-rich dipeptide-repeat proteins are synthesized in a length-dependent manner. However, despite triggering this pathway, these arginine-rich dipeptide-repeat proteins are not efficiently processed by the core components of the ribosome-associated quality control complex (listerin, nuclear-export mediator factor and valosin containing protein) partly due to lack of lysine residues, which precludes ubiquitination. Deficient processing by this complex may be implicated in C9orf72-expansion associated disease as dipeptide-repeat protein inclusions were observed to be predominantly devoid of ubiquitin and co-localize with nuclear-export mediator factor in mutation carriers' frontal cortex and cerebellum tissue. These findings suggest that impaired processing of these arginine-rich dipeptide-repeat proteins derived from repeat-associated non-AUG translation by the ribosome-associated quality control complex may contribute to protein homeostasis dysregulation observed in C9orf72-expansion amyotrophic lateral sclerosis and frontotemporal degeneration neuropathogenesis.
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Affiliation(s)
- Ashley P Viera Ortiz
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gregory Cajka
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Olamide A Olatunji
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bailey Mikytuck
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ophir Shalem
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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43
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Protic D, Polli R, Hwang YH, Mendoza G, Hagerman R, Durbin-Johnson B, Hayward BE, Usdin K, Murgia A, Tassone F. Activation Ratio Correlates with IQ in Female Carriers of the FMR1 Premutation. Cells 2023; 12:1711. [PMID: 37443745 PMCID: PMC10341054 DOI: 10.3390/cells12131711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/17/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Carriers of the FMR1 premutation (PM) allele are at risk of one or more clinical conditions referred to as FX premutation-associated conditions (FXPAC). Since the FMR1 gene is on the X chromosome, the activation ratio (AR) may impact the risk, age of onset, progression, and severity of these conditions. The aim of this study was to evaluate the reliability of AR measured using different approaches and to investigate potential correlations with clinical outcomes. Molecular and clinical assessments were obtained for 30 PM female participants, and AR was assessed using both Southern blot analysis (AR-Sb) and methylation PCR (AR-mPCR). Higher ARs were associated with lower FMR1 transcript levels for any given repeat length. The higher AR-Sb was significantly associated with performance, verbal, and full-scale IQ scores, confirming previous reports. However, the AR-mPCR was not significantly associated (p > 0.05) with these measures. Similarly, the odds of depression and the number of medical conditions were correlated with higher AR-Sb but not correlated with a higher AR-mPCR. This study suggests that AR-Sb may be a more reliable measure of the AR in female carriers of PM alleles. However, further studies are warranted in a larger sample size to fully evaluate the methylation status in these participants and how it may affect the clinical phenotype.
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Affiliation(s)
- Dragana Protic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;
| | - Roberta Polli
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, 35128 Padova, Italy; (R.P.); (A.M.)
- Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, 35128 Padova, Italy
| | - Ye Hyun Hwang
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA; (Y.H.H.); (G.M.)
| | - Guadalupe Mendoza
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA; (Y.H.H.); (G.M.)
| | - Randi Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute UCDH, University of California Davis, Sacramento, CA 95817, USA;
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Blythe Durbin-Johnson
- Department of Public Health Sciences, Division of Biostatistics, University of California, Davis, CA 95616, USA;
| | - Bruce E. Hayward
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (B.E.H.); (K.U.)
| | - Karen Usdin
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (B.E.H.); (K.U.)
| | - Alessandra Murgia
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, 35128 Padova, Italy; (R.P.); (A.M.)
- Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, 35128 Padova, Italy
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA; (Y.H.H.); (G.M.)
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute UCDH, University of California Davis, Sacramento, CA 95817, USA;
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44
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Zhang Y, Huang J, Yu K, Cui X. G-Quadruplexes Formation by the C9orf72 Nucleotide Repeat Expansion d(GGGGCC) n and Conformation Regulation by Fangchinoline. Molecules 2023; 28:4671. [PMID: 37375224 DOI: 10.3390/molecules28124671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/01/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The G-quadruplex (GQ)-forming hexanucleotide repeat expansion (HRE) in the C9orf72 (C9) gene has been found to be the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (collectively, C9ALS/FTD), implying the great significance of modulating C9-HRE GQ structures in C9ALS/FTD therapeutic treatment strategies. In this study, we investigated the GQ structures formed by varied lengths of C9-HRE DNA sequences d(GGGGCC)4 (C9-24mer) and d(GGGGCC)8 (C9-48mer), and found that the C9-24mer forms anti-parallel GQ (AP-GQ) in the presence of potassium ions, while the long C9-48mer bearing eight guanine tracts forms unstacked tandem GQ consisting of two C9-24mer unimolecular AP-GQs. Moreover, the natural small molecule Fangchinoline was screened out in order to be able to stabilize and alter the C9-HRE DNA to parallel GQ topology. Further study of the interaction of Fangchinoline with the C9-HRE RNA GQ unit r(GGGGCC)4 (C9-RNA) revealed that it can also recognize and improve the thermal stability of C9-HRE RNA GQ. Finally, use of AutoDock simulation results indicated that Fangchinoline binds to the groove regions of the parallel C9-HRE GQs. These findings pave the way for further studies of GQ structures formed by pathologically related long C9-HRE sequences, and also provide a natural small-molecule ligand that modulates the structure and stability of C9-HRE GQ, both in DNA and RNA levels. Altogether, this work may contribute to therapeutic approaches of C9ALS/FTD which take the upstream C9-HRE DNA region, as well as the toxic C9-HRE RNA, as targets.
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Affiliation(s)
- Yun Zhang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Junliu Huang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Kainan Yu
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Xiaojie Cui
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing 100081, China
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45
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Lee HG, Imaichi S, Kraeutler E, Aguilar R, Lee YW, Sheridan SD, Lee JT. Site-specific R-loops induce CGG repeat contraction and fragile X gene reactivation. Cell 2023; 186:2593-2609.e18. [PMID: 37209683 PMCID: PMC11505655 DOI: 10.1016/j.cell.2023.04.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/15/2023] [Accepted: 04/26/2023] [Indexed: 05/22/2023]
Abstract
Here, we describe an approach to correct the genetic defect in fragile X syndrome (FXS) via recruitment of endogenous repair mechanisms. A leading cause of autism spectrum disorders, FXS results from epigenetic silencing of FMR1 due to a congenital trinucleotide (CGG) repeat expansion. By investigating conditions favorable to FMR1 reactivation, we find MEK and BRAF inhibitors that induce a strong repeat contraction and full FMR1 reactivation in cellular models. We trace the mechanism to DNA demethylation and site-specific R-loops, which are necessary and sufficient for repeat contraction. A positive feedback cycle comprising demethylation, de novo FMR1 transcription, and R-loop formation results in the recruitment of endogenous DNA repair mechanisms that then drive excision of the long CGG repeat. Repeat contraction is specific to FMR1 and restores the production of FMRP protein. Our study therefore identifies a potential method of treating FXS in the future.
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Affiliation(s)
- Hun-Goo Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Sachiko Imaichi
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Elizabeth Kraeutler
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Rodrigo Aguilar
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Yong-Woo Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Steven D Sheridan
- Center for Quantitative Health Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02114, USA
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA.
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46
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Tseng YJ, Malik I, Deng X, Krans A, Jansen-West K, Tank EM, Gomez NB, Sher R, Petrucelli L, Barmada SJ, Todd PK. Ribosomal quality control factors inhibit repeat-associated non-AUG translation from GC-rich repeats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544135. [PMID: 37333274 PMCID: PMC10274811 DOI: 10.1101/2023.06.07.544135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
A GGGGCC (G4C2) hexanucleotide repeat expansion in C9ORF72 causes amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD), while a CGG trinucleotide repeat expansion in FMR1 leads to the neurodegenerative disorder Fragile X-associated tremor/ataxia syndrome (FXTAS). These GC-rich repeats form RNA secondary structures that support repeat-associated non-AUG (RAN) translation of toxic proteins that contribute to disease pathogenesis. Here we assessed whether these same repeats might trigger stalling and interfere with translational elongation. We find that depletion of ribosome-associated quality control (RQC) factors NEMF, LTN1, and ANKZF1 markedly boost RAN translation product accumulation from both G4C2 and CGG repeats while overexpression of these factors reduces RAN production in both reporter cell lines and C9ALS/FTD patient iPSC-derived neurons. We also detected partially made products from both G4C2 and CGG repeats whose abundance increased with RQC factor depletion. Repeat RNA sequence, rather than amino acid content, is central to the impact of RQC factor depletion on RAN translation - suggesting a role for RNA secondary structure in these processes. Together, these findings suggest that ribosomal stalling and RQC pathway activation during RAN translation elongation inhibits the generation of toxic RAN products. We propose augmenting RQC activity as a therapeutic strategy in GC-rich repeat expansion disorders.
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Affiliation(s)
- Yi-Ju Tseng
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Xiexiong Deng
- Department of Molecular, Cellular and Developmental Biology, Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, 48109, USA
| | - Karen Jansen-West
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | | | - Nicolas B. Gomez
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Roger Sher
- Department of Neurobiology and Behavior & Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY, 11794, USA
| | | | - Sami J. Barmada
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Peter K. Todd
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, 48109, USA
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47
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Dias CM, Issac B, Sun L, Lukowicz A, Talukdar M, Akula SK, Miller MB, Walsh K, Rockowitz S, Walsh CA. Glial dysregulation in the human brain in fragile X-associated tremor/ataxia syndrome. Proc Natl Acad Sci U S A 2023; 120:e2300052120. [PMID: 37252957 PMCID: PMC10265985 DOI: 10.1073/pnas.2300052120] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 04/03/2023] [Indexed: 06/01/2023] Open
Abstract
Short trinucleotide expansions at the FMR1 locus are associated with the late-onset condition fragile X-associated tremor/ataxia syndrome (FXTAS), which shows very different clinical and pathological features from fragile X syndrome (associated with longer expansions), with no clear molecular explanation for these marked differences. One prevailing theory posits that the shorter, premutation expansion uniquely causes extreme neurotoxic increases in FMR1 mRNA (i.e., four to eightfold increases), but evidence to support this hypothesis is largely derived from analysis of peripheral blood. We applied single-nucleus RNA sequencing to postmortem frontal cortex and cerebellum from 7 individuals with premutation and matched controls (n = 6) to assess cell type-specific molecular neuropathology. We found only modest upregulation (~1.3-fold) of FMR1 in some glial populations associated with premutation expansions. In premutation cases, we also identified decreased astrocyte proportions in the cortex. Differential expression and gene ontology analysis demonstrated altered neuroregulatory roles of glia. Using network analyses, we identified cell type-specific and region-specific patterns of FMR1 protein target gene dysregulation unique to premutation cases, with notable network dysregulation in the cortical oligodendrocyte lineage. We used pseudotime trajectory analysis to determine how oligodendrocyte development was altered and identified differences in early gene expression in oligodendrocyte trajectories in premutation cases specifically, implicating early cortical glial developmental perturbations. These findings challenge dogma regarding extremely elevated FMR1 increases in FXTAS and implicate glial dysregulation as a critical facet of premutation pathophysiology, representing potential unique therapeutic targets directly derived from the human condition.
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Affiliation(s)
- Caroline M. Dias
- Division of Developmental Medicine, Boston Children’s Hospital, Boston, MA02115
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Department of Pediatrics, Harvard Medical School, Boston, MA02115
- Department of Pediatrics, Section of Developmental Pediatrics, Section of Genetics and Metabolism, and Denver Fragile X Clinic and Research Center, Children’s Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Biju Issac
- Research Computing, Department of Information Technology, Boston Children’s Hospital, Boston, MA02115
| | - Liang Sun
- Research Computing, Department of Information Technology, Boston Children’s Hospital, Boston, MA02115
| | - Abigail Lukowicz
- Department of Pediatrics, Section of Developmental Pediatrics, Section of Genetics and Metabolism, and Denver Fragile X Clinic and Research Center, Children’s Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Maya Talukdar
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Harvard-Massachusetts Institute of Technology MD/PhD Program, Program in Bioinformatics & Integrative Genomics, Harvard Medical School, Boston, MA02115
| | - Shyam K. Akula
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Harvard-Massachusetts Institute of Technology MD/PhD Program, Program in Neuroscience, Harvard Medical School, Boston, MA02115
| | - Michael B. Miller
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
| | - Katherine Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
| | - Shira Rockowitz
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Research Computing, Department of Information Technology, Boston Children’s Hospital, Boston, MA02115
| | - Christopher A. Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Department of Pediatrics, Harvard Medical School, Boston, MA02115
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Department of Neurology, Harvard Medical School, Boston, MA02115
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48
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Wright SE, Todd PK. Native functions of short tandem repeats. eLife 2023; 12:e84043. [PMID: 36940239 PMCID: PMC10027321 DOI: 10.7554/elife.84043] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/08/2023] [Indexed: 03/21/2023] Open
Abstract
Over a third of the human genome is comprised of repetitive sequences, including more than a million short tandem repeats (STRs). While studies of the pathologic consequences of repeat expansions that cause syndromic human diseases are extensive, the potential native functions of STRs are often ignored. Here, we summarize a growing body of research into the normal biological functions for repetitive elements across the genome, with a particular focus on the roles of STRs in regulating gene expression. We propose reconceptualizing the pathogenic consequences of repeat expansions as aberrancies in normal gene regulation. From this altered viewpoint, we predict that future work will reveal broader roles for STRs in neuronal function and as risk alleles for more common human neurological diseases.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Neuroscience, Picower InstituteCambridgeUnited States
| | - Peter K Todd
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- VA Ann Arbor Healthcare SystemAnn ArborUnited States
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49
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Straub D, Schmitt LM, Boggs AE, Horn PS, Dominick KC, Gross C, Erickson CA. A sensitive and reproducible qRT-PCR assay detects physiological relevant trace levels of FMR1 mRNA in individuals with Fragile X syndrome. Sci Rep 2023; 13:3808. [PMID: 36882476 PMCID: PMC9992378 DOI: 10.1038/s41598-023-29786-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/10/2023] [Indexed: 03/09/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited intellectual disability. FXS is caused by a trinucleotide repeat expansion in the 5' untranslated region of the FMR1 gene, which leads to gene methylation, transcriptional silencing, and lack of expression of Fragile X Messenger Riboprotein (FMRP). Currently available FXS therapies are inefficient, and the disease severity is highly variable, making it difficult to predict disease trajectory and treatment response. We and others have recently shown that a subset of full-mutation, fully-methylated (FM-FM) males with FXS express low amounts of FMRP which could contribute to phenotypic variability. To better understand the underlying mechanisms, we developed a sensitive qRT-PCR assay to detect FMR1 mRNA in blood. This assay reproducibly detects trace amounts of FMR1 mRNA in a subset of FM-FM males, suggesting that current Southern Blot and PCR determination of FM-FM status is not always associated with complete transcriptional silencing. The functional relevance of trace-level FMR1 mRNA is confirmed by showing a positive correlation with cognitive function; however, phenotypic variability is not fully explained by FMR1 expression. These results corroborate the need for better molecular assays for FXS diagnosis and encourage studies to elucidate the factors contributing to the phenotypic variability of FXS.
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Affiliation(s)
- Devan Straub
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
| | - Lauren M Schmitt
- Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
| | - Anna E Boggs
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
| | - Paul S Horn
- Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
- Division of Neurology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH, 45229-3039, USA
| | - Kelli C Dominick
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Stetson Building Suite 3200, 260 Stetson Street, Cincinnati, OH, 45267-0559, USA
| | - Christina Gross
- Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
- Division of Neurology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH, 45229-3039, USA
| | - Craig A Erickson
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA.
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Stetson Building Suite 3200, 260 Stetson Street, Cincinnati, OH, 45267-0559, USA.
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50
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Reyes CJF, Asano K. Between Order and Chaos: Understanding the Mechanism and Pathology of RAN Translation. Biol Pharm Bull 2023; 46:139-146. [PMID: 36724941 DOI: 10.1248/bpb.b22-00448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Repeat-associated non-AUG (RAN) translation is a pathogenic mechanism in which repetitive sequences are translated into aggregation-prone proteins from multiple reading frames, even without a canonical AUG start codon. Since its discovery in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), RAN translation is now known to occur in the context of 12 disease-linked repeat expansions. This review discusses recent advances in understanding the regulatory mechanisms controlling RAN translation and its contribution to the pathophysiology of repeat expansion diseases. We discuss the key findings in the context of Fragile X Tremor Ataxia Syndrome (FXTAS), a neurodegenerative disorder caused by a CGG repeat expansion in the 5' untranslated region of FMR1.
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Affiliation(s)
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University.,Laboratory of Translational Control Study, Graduate School of Integrated Sciences for Life, Hiroshima University.,Hiroshima Research Center for Healthy Aging, Hiroshima University
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