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1
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Minisy FM, Shawki HH, Fujita T, Moustafa AM, Sener R, Nishio Y, Shimada IS, Saitoh S, Sugiura-Ogasawara M, Oishi H. Transcription Factor 23 is an Essential Determinant of Murine Term Parturition. Mol Cell Biol 2024; 44:316-333. [PMID: 39014976 PMCID: PMC11296541 DOI: 10.1080/10985549.2024.2376146] [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: 03/20/2024] [Revised: 05/27/2024] [Accepted: 06/30/2024] [Indexed: 07/18/2024] Open
Abstract
Pregnancy involving intricate tissue transformations governed by the progesterone hormone (P4). P4 signaling via P4 receptors (PRs) is vital for endometrial receptivity, decidualization, myometrial quiescence, and labor initiation. This study explored the role of TCF23 as a downstream target of PR during pregnancy. TCF23 was found to be expressed in female reproductive organs, predominantly in uterine stromal and smooth muscle cells. Tcf23 expression was high during midgestation and was specifically regulated by P4, but not estrogen. The Tcf23 knockout (KO) mouse was generated and analyzed. Female KO mice aged 4-6 months exhibited subfertility, reduced litter size, and defective parturition. Uterine histology revealed disrupted myometrial structure, altered collagen organization, and disarrayed smooth muscle sheets at the conceptus sites of KO mice. RNA-Seq analysis of KO myometrium revealed dysregulation of genes associated with cell adhesion and extracellular matrix organization. TCF23 potentially modulates TCF12 activity to mediate cell-cell adhesion and matrix modulation in smooth muscle cells. Overall, TCF23 deficiency leads to impaired myometrial remodeling, causing parturition delay and fetal demise. This study sheds light on the critical role of TCF23 as a dowstream mediator of PR in uterine remodeling, reflecting the importance of cell-cell communication and matrix dynamics in myometrial activation and parturition.
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Affiliation(s)
- Fatma M. Minisy
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Pathology, National Research Centre, Cairo, Egypt
| | - Hossam H. Shawki
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Animal Genetic Resources, National Gene Bank of Egypt, ARC, Giza, Egypt
| | - Tsubasa Fujita
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Ahmed M. Moustafa
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Rumeysa Sener
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Youske Nishio
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Issei S. Shimada
- Department of Cell Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mayumi Sugiura-Ogasawara
- Department of Obstetrics and Gynecology, Nagoya City University, Graduate School of Medical Sciences, Nagoya, Japan
| | - Hisashi Oishi
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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2
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Gharpure M, Chen J, Nerella R, Vyavahare S, Kumar S, Isales CM, Hamrick M, Adusumilli S, Fulzele S. Sex-specific alteration in human muscle transcriptome with age. GeroScience 2023:10.1007/s11357-023-00795-5. [PMID: 37106281 PMCID: PMC10400750 DOI: 10.1007/s11357-023-00795-5] [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: 01/24/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
Sarcopenia is a medical condition that progressively develops with age and results in reduced skeletal muscle mass, alteration in muscle composition, and decreased muscle strength. Several clinical studies suggested that sarcopenia disproportionally affects males and females with age. Despite this knowledge, the molecular mechanism governing the pathophysiology is not well understood in a sex-specific manner. In this study, we utilized human gastrocnemius muscles from males and females to identify differentially regulated genes with age. We found 269 genes with at least a twofold expression difference in the aged muscle transcriptome. Among the female muscle samples, there were 239 differentially regulated genes, and the novel protein-coding genes include KIF20A, PIMREG, MTRNR2L6, TRPV6, EFNA2, RNF24, and SFN. In aged male skeletal muscle, there were 166 differentially regulated genes, and the novel-protein coding genes are CENPK, CDKN2A, BHLHA15, and EPHA. Gene Ontology (GO) enrichment revealed glucose catabolism, NAD metabolic processes, and muscle fiber transition pathways that are involved in aged female skeletal muscle, whereas replicative senescence, cytochrome C release, and muscle composition pathways are disrupted in aged male skeletal muscle. Targeting these novels, differentially regulated genes, and signaling pathways could serve as sex-specific therapeutic targets to combat the age-related onset of sarcopenia and promote healthy aging.
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Affiliation(s)
- Mohini Gharpure
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
| | - Jie Chen
- Division of Biostatistics and Data Science, Department of Population Health Sciences, Augusta University, Augusta, GA, USA
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
| | - Resheek Nerella
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
- Augusta University, Augusta, GA, 30912, USA
| | - Sagar Vyavahare
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
| | - Sandeep Kumar
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
| | - Carlos M Isales
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
| | - Mark Hamrick
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | | | - Sadanand Fulzele
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA.
- Center for Healthy Aging, Augusta University, Augusta, GA, USA.
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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3
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Wöhner M, Pinter T, Bönelt P, Hagelkruys A, Kostanova-Poliakova D, Stadlmann J, Konieczny SF, Fischer M, Jaritz M, Busslinger M. The Xbp1-regulated transcription factor Mist1 restricts antibody secretion by restraining Blimp1 expression in plasma cells. Front Immunol 2022; 13:859598. [PMID: 36618345 PMCID: PMC9811352 DOI: 10.3389/fimmu.2022.859598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 11/15/2022] [Indexed: 12/24/2022] Open
Abstract
Antibody secretion by plasma cells provides acute and long-term protection against pathogens. The high secretion potential of plasma cells depends on the unfolded protein response, which is controlled by the transcription factor Xbp1. Here, we analyzed the Xbp1-dependent gene expression program of plasma cells and identified Bhlha15 (Mist1) as the most strongly activated Xbp1 target gene. As Mist1 plays an important role in other secretory cell types, we analyzed in detail the phenotype of Mist1-deficient plasma cells in Cd23-Cre Bhlha15 fl/fl mice under steady-state condition or upon NP-KLH immunization. Under both conditions, Mist1-deficient plasma cells were 1.4-fold reduced in number and exhibited increased IgM production and antibody secretion compared to control plasma cells. At the molecular level, Mist1 regulated a largely different set of target genes compared with Xbp1. Notably, expression of the Blimp1 protein, which is known to activate immunoglobulin gene expression and to contribute to antibody secretion, was 1.3-fold upregulated in Mist1-deficient plasma cells, which led to a moderate downregulation of most Blimp1-repressed target genes in the absence of Mist1. Importantly, a 2-fold reduction of Blimp1 (Prdm1) expression was sufficient to restore the cell number and antibody expression of plasma cells in Prdm1 Gfp/+ Cd23-Cre Bhlha15 fl/fl mice to the same level seen in control mice. Together, these data indicate that Mist1 restricts antibody secretion by restraining Blimp1 expression, which likely contributes to the viability of plasma cells.
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Affiliation(s)
- Miriam Wöhner
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Theresa Pinter
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Peter Bönelt
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Astrid Hagelkruys
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | | | - Johannes Stadlmann
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Stephen F. Konieczny
- Department of Biological Science, Purdue University, West Lafayette, IN, United States
| | - Maria Fischer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Markus Jaritz
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Meinrad Busslinger
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria,*Correspondence: Meinrad Busslinger,
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4
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Battistelli C, Garbo S, Maione R. MyoD-Induced Trans-Differentiation: A Paradigm for Dissecting the Molecular Mechanisms of Cell Commitment, Differentiation and Reprogramming. Cells 2022; 11:3435. [PMID: 36359831 PMCID: PMC9654159 DOI: 10.3390/cells11213435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 10/23/2022] [Accepted: 10/28/2022] [Indexed: 10/20/2023] Open
Abstract
The discovery of the skeletal muscle-specific transcription factor MyoD represents a milestone in the field of transcriptional regulation during differentiation and cell-fate reprogramming. MyoD was the first tissue-specific factor found capable of converting non-muscle somatic cells into skeletal muscle cells. A unique feature of MyoD, with respect to other lineage-specific factors able to drive trans-differentiation processes, is its ability to dramatically change the cell fate even when expressed alone. The present review will outline the molecular strategies by which MyoD reprograms the transcriptional regulation of the cell of origin during the myogenic conversion, focusing on the activation and coordination of a complex network of co-factors and epigenetic mechanisms. Some molecular roadblocks, found to restrain MyoD-dependent trans-differentiation, and the possible ways for overcoming these barriers, will also be discussed. Indeed, they are of critical importance not only to expand our knowledge of basic muscle biology but also to improve the generation skeletal muscle cells for translational research.
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Affiliation(s)
| | | | - Rossella Maione
- Department of Molecular Medicine, Sapienza University of Rome, Viale Regina Elena 324, 00161 Rome, Italy
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5
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Kny M, Fielitz J. Hidden Agenda - The Involvement of Endoplasmic Reticulum Stress and Unfolded Protein Response in Inflammation-Induced Muscle Wasting. Front Immunol 2022; 13:878755. [PMID: 35615361 PMCID: PMC9124858 DOI: 10.3389/fimmu.2022.878755] [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: 02/18/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Critically ill patients at the intensive care unit (ICU) often develop a generalized weakness, called ICU-acquired weakness (ICUAW). A major contributor to ICUAW is muscle atrophy, a loss of skeletal muscle mass and function. Skeletal muscle assures almost all of the vital functions of our body. It adapts rapidly in response to physiological as well as pathological stress, such as inactivity, immobilization, and inflammation. In response to a reduced workload or inflammation muscle atrophy develops. Recent work suggests that adaptive or maladaptive processes in the endoplasmic reticulum (ER), also known as sarcoplasmic reticulum, contributes to this process. In muscle cells, the ER is a highly specialized cellular organelle that assures calcium homeostasis and therefore muscle contraction. The ER also assures correct folding of proteins that are secreted or localized to the cell membrane. Protein folding is a highly error prone process and accumulation of misfolded or unfolded proteins can cause ER stress, which is counteracted by the activation of a signaling network known as the unfolded protein response (UPR). Three ER membrane residing molecules, protein kinase R-like endoplasmic reticulum kinase (PERK), inositol requiring protein 1a (IRE1a), and activating transcription factor 6 (ATF6) initiate the UPR. The UPR aims to restore ER homeostasis by reducing overall protein synthesis and increasing gene expression of various ER chaperone proteins. If ER stress persists or cannot be resolved cell death pathways are activated. Although, ER stress-induced UPR pathways are known to be important for regulation of skeletal muscle mass and function as well as for inflammation and immune response its function in ICUAW is still elusive. Given recent advances in the development of ER stress modifying molecules for neurodegenerative diseases and cancer, it is important to know whether or not therapeutic interventions in ER stress pathways have favorable effects and these compounds can be used to prevent or treat ICUAW. In this review, we focus on the role of ER stress-induced UPR in skeletal muscle during critical illness and in response to predisposing risk factors such as immobilization, starvation and inflammation as well as ICUAW treatment to foster research for this devastating clinical problem.
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Affiliation(s)
- Melanie Kny
- Experimental and Clinical Research Center (ECRC), Charité-Universitätsmedizin Berlin, Max Delbrück Center (MDC) for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Jens Fielitz
- Department of Molecular Cardiology, DZHK (German Center for Cardiovascular Research), Partner Site, Greifswald, Germany
- Department of Internal Medicine B, Cardiology, University Medicine Greifswald, Greifswald, Germany
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6
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Homodimeric and Heterodimeric Interactions among Vertebrate Basic Helix-Loop-Helix Transcription Factors. Int J Mol Sci 2021; 22:ijms222312855. [PMID: 34884664 PMCID: PMC8657788 DOI: 10.3390/ijms222312855] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/11/2021] [Accepted: 11/17/2021] [Indexed: 01/01/2023] Open
Abstract
The basic helix–loop–helix transcription factor (bHLH TF) family is involved in tissue development, cell differentiation, and disease. These factors have transcriptionally positive, negative, and inactive functions by combining dimeric interactions among family members. The best known bHLH TFs are the E-protein homodimers and heterodimers with the tissue-specific TFs or ID proteins. These cooperative and dynamic interactions result in a complex transcriptional network that helps define the cell’s fate. Here, the reported dimeric interactions of 67 vertebrate bHLH TFs with other family members are summarized in tables, including specifications of the experimental techniques that defined the dimers. The compilation of these extensive data underscores homodimers of tissue-specific bHLH TFs as a central part of the bHLH regulatory network, with relevant positive and negative transcriptional regulatory roles. Furthermore, some sequence-specific TFs can also form transcriptionally inactive heterodimers with each other. The function, classification, and developmental role for all vertebrate bHLH TFs in four major classes are detailed.
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7
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Mechanisms of Binding Specificity among bHLH Transcription Factors. Int J Mol Sci 2021; 22:ijms22179150. [PMID: 34502060 PMCID: PMC8431614 DOI: 10.3390/ijms22179150] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/14/2021] [Accepted: 08/18/2021] [Indexed: 12/25/2022] Open
Abstract
The transcriptome of every cell is orchestrated by the complex network of interaction between transcription factors (TFs) and their binding sites on DNA. Disruption of this network can result in many forms of organism malfunction but also can be the substrate of positive natural selection. However, understanding the specific determinants of each of these individual TF-DNA interactions is a challenging task as it requires integrating the multiple possible mechanisms by which a given TF ends up interacting with a specific genomic region. These mechanisms include DNA motif preferences, which can be determined by nucleotide sequence but also by DNA’s shape; post-translational modifications of the TF, such as phosphorylation; and dimerization partners and co-factors, which can mediate multiple forms of direct or indirect cooperative binding. Binding can also be affected by epigenetic modifications of putative target regions, including DNA methylation and nucleosome occupancy. In this review, we describe how all these mechanisms have a role and crosstalk in one specific family of TFs, the basic helix-loop-helix (bHLH), with a very conserved DNA binding domain and a similar DNA preferred motif, the E-box. Here, we compile and discuss a rich catalog of strategies used by bHLH to acquire TF-specific genome-wide landscapes of binding sites.
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8
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Sahoo SS, Mishra C, Kaushik R, Rout PK, Singh MK, Bhusan S, Dige MS. Association of a SNP in KISS 1 gene with reproductive traits in goats. BIOL RHYTHM RES 2019. [DOI: 10.1080/09291016.2019.1608730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Siddhant Sekhar Sahoo
- Department of Animal Breeding and Genetics, College of Veterinary Science and Animal Husbandry, OUAT, Bhubaneswar, India
| | - Chinmoy Mishra
- Department of Animal Breeding and Genetics, College of Veterinary Science and Animal Husbandry, OUAT, Bhubaneswar, India
| | - Rakesh Kaushik
- Animal Genetics and Breeding Division, ICAR- Central Institute for Research on Goats, Mathura, India
| | - Pramod Kumar Rout
- Animal Genetics and Breeding Division, ICAR- Central Institute for Research on Goats, Mathura, India
| | - Manoj Kumar Singh
- Animal Genetics and Breeding Division, ICAR- Central Institute for Research on Goats, Mathura, India
| | - Saket Bhusan
- Animal Genetics and Breeding Division, ICAR- Central Institute for Research on Goats, Mathura, India
| | - Mahesh Shivanand Dige
- Animal Genetics and Breeding Division, ICAR- Central Institute for Research on Goats, Mathura, India
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9
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Fogarty MJ, Sieck GC. Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals. Compr Physiol 2019; 9:715-766. [PMID: 30873594 PMCID: PMC7082849 DOI: 10.1002/cphy.c180012] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.
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Affiliation(s)
- Matthew J Fogarty
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
| | - Gary C Sieck
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
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10
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Raccaud M, Friman ET, Alber AB, Agarwal H, Deluz C, Kuhn T, Gebhardt JCM, Suter DM. Mitotic chromosome binding predicts transcription factor properties in interphase. Nat Commun 2019; 10:487. [PMID: 30700703 PMCID: PMC6353955 DOI: 10.1038/s41467-019-08417-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/08/2019] [Indexed: 12/31/2022] Open
Abstract
Mammalian transcription factors (TFs) differ broadly in their nuclear mobility and sequence-specific/non-specific DNA binding. How these properties affect their ability to occupy specific genomic sites and modify the epigenetic landscape is unclear. The association of TFs with mitotic chromosomes observed by fluorescence microscopy is largely mediated by non-specific DNA interactions and differs broadly between TFs. Here we combine quantitative measurements of mitotic chromosome binding (MCB) of 501 TFs, TF mobility measurements by fluorescence recovery after photobleaching, single molecule imaging of DNA binding, and mapping of TF binding and chromatin accessibility. TFs associating to mitotic chromosomes are enriched in DNA-rich compartments in interphase and display slower mobility in interphase and mitosis. Remarkably, MCB correlates with relative TF on-rates and genome-wide specific site occupancy, but not with TF residence times. This suggests that non-specific DNA binding properties of TFs regulate their search efficiency and occupancy of specific genomic sites.
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Affiliation(s)
- Mahé Raccaud
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Elias T Friman
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Andrea B Alber
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Harsha Agarwal
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Cédric Deluz
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Timo Kuhn
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - J Christof M Gebhardt
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - David M Suter
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
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11
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Abstract
Transcription factors (TFs) drive various biological processes ranging from embryonic development to carcinogenesis. Here, we employ a recently developed concatenated tandem array of consensus TF response elements (catTFRE) approach to profile the activated TFs in 24 adult and 8 fetal mouse tissues on proteome scale. A total of 941 TFs are quantitatively identified, representing over 60% of the TFs in the mouse genome. Using an integrated omics approach, we present a TF network in the major organs of the mouse, allowing data mining and generating knowledge to elucidate the roles of TFs in various biological processes, including tissue type maintenance and determining the general features of a physiological system. This study provides a landscape of TFs in mouse tissues that can be used to elucidate transcriptional regulatory specificity and programming and as a baseline that may facilitate understanding diseases that are regulated by TFs. While we have abundant data for transcription factor (TF) binding sites and TF expression at the mRNA level, our knowledge of TFs at the protein level and their DNA-binding activities is sparser. Here, the authors address this by using the catTFRE approach to profile active TFs in 24 adult and 8 fetal mouse tissues, and presenting the TF networks in major mouse organs.
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12
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Wang C, Wang M, Arrington J, Shan T, Yue F, Nie Y, Tao WA, Kuang S. Ascl2 inhibits myogenesis by antagonizing the transcriptional activity of myogenic regulatory factors. Development 2016; 144:235-247. [PMID: 27993983 DOI: 10.1242/dev.138099] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 12/06/2016] [Indexed: 12/12/2022]
Abstract
Myogenic regulatory factors (MRFs), including Myf5, MyoD (Myod1) and Myog, are muscle-specific transcription factors that orchestrate myogenesis. Although MRFs are essential for myogenic commitment and differentiation, timely repression of their activity is necessary for the self-renewal and maintenance of muscle stem cells (satellite cells). Here, we define Ascl2 as a novel inhibitor of MRFs. During mouse development, Ascl2 is transiently detected in a subpopulation of Pax7+ MyoD+ progenitors (myoblasts) that become Pax7+ MyoD- satellite cells prior to birth, but is not detectable in postnatal satellite cells. Ascl2 knockout in embryonic myoblasts decreases both the number of Pax7+ cells and the proportion of Pax7+ MyoD- cells. Conversely, overexpression of Ascl2 inhibits the proliferation and differentiation of cultured myoblasts and impairs the regeneration of injured muscles. Ascl2 competes with MRFs for binding to E-boxes in the promoters of muscle genes, without activating gene transcription. Ascl2 also forms heterodimers with classical E-proteins to sequester their transcriptional activity on MRF genes. Accordingly, MyoD or Myog expression rescues myogenic differentiation despite Ascl2 overexpression. Ascl2 expression is regulated by Notch signaling, a key governor of satellite cell self-renewal. These data demonstrate that Ascl2 inhibits myogenic differentiation by targeting MRFs and facilitates the generation of postnatal satellite cells.
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Affiliation(s)
- Chao Wang
- Department of Animal Science, Purdue University, West Lafayette, IN 47906, USA
| | - Min Wang
- Department of Animal Science, Purdue University, West Lafayette, IN 47906, USA
| | - Justine Arrington
- Department of Chemistry, Purdue University, West Lafayette, IN 47906, USA
| | - Tizhong Shan
- Department of Animal Science, Purdue University, West Lafayette, IN 47906, USA
| | - Feng Yue
- Department of Animal Science, Purdue University, West Lafayette, IN 47906, USA
| | - Yaohui Nie
- Department of Animal Science, Purdue University, West Lafayette, IN 47906, USA
| | - Weiguo Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, IN 47906, USA.,Center for Cancer Research, Purdue University, West Lafayette, IN 47906, USA
| | - Shihuan Kuang
- Department of Animal Science, Purdue University, West Lafayette, IN 47906, USA .,Center for Cancer Research, Purdue University, West Lafayette, IN 47906, USA
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13
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MIST1 Links Secretion and Stress as both Target and Regulator of the Unfolded Protein Response. Mol Cell Biol 2016; 36:2931-2944. [PMID: 27644325 DOI: 10.1128/mcb.00366-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 07/22/2016] [Accepted: 09/10/2016] [Indexed: 12/28/2022] Open
Abstract
Transcriptional networks that govern secretory cell specialization, including instructing cells to develop a unique cytoarchitecture, amass extensive protein synthesis machinery, and be embodied to respond to endoplasmic reticulum (ER) stress, remain largely uncharacterized. In this study, we discovered that the secretory cell transcription factor MIST1 (Bhlha15), previously shown to be essential for cytoskeletal organization and secretory activity, also functions as a potent ER stress-inducible transcriptional regulator. Genome-wide DNA binding studies, coupled with genetic mouse models, revealed MIST1 gene targets that function along the entire breadth of the protein synthesis, processing, transport, and exocytosis networks. Additionally, key MIST1 targets are essential for alleviating ER stress in these highly specialized cells. Indeed, MIST1 functions as a coregulator of the unfolded protein response (UPR) master transcription factor XBP1 for a portion of target genes that contain adjacent MIST1 and XBP1 binding sites. Interestingly, Mist1 gene expression is induced during ER stress by XBP1, but as ER stress subsides, MIST1 serves as a feedback inhibitor, directly binding the Xbp1 promoter and repressing Xbp1 transcript production. Together, our findings provide a new paradigm for XBP1-dependent UPR regulation and position MIST1 as a potential biotherapeutic for numerous human diseases.
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Huang Y, Chen B, Ye M, Liang P, Zhangfang Y, Huang J, Liu M, Songyang Z, Ma W. Ccndbp1 is a new positive regulator of skeletal myogenesis. J Cell Sci 2016; 129:2767-77. [PMID: 27235421 DOI: 10.1242/jcs.184234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 05/02/2016] [Indexed: 12/26/2022] Open
Abstract
Skeletal myogenesis is a multistep process in which basic helix-loop-helix (bHLH) transcription factors, such as MyoD (also known as MyoD1), bind to E-boxes and activate downstream genes. Ccndbp1 is a HLH protein that lacks a DNA-binding region, and its function in skeletal myogenesis is currently unknown. We generated Ccndbp1-null mice by using CRISPR-Cas9. Notably, in Ccndbp1-null mice, the cross sectional area of the skeletal tibialis anterior muscle was smaller, and muscle regeneration ability and grip strength were impaired, compared with those of wild type. This phenotype resembled that of myofiber hypotrophy in some human myopathies or amyoplasia. Ccndbp1 expression was upregulated during C2C12 myogenesis. Ccndbp1 overexpression promoted myogenesis, whereas knockdown of Ccndbp1 inhibited myogenic differentiation. Co-transfection of Ccndbp1 with MyoD and/or E47 (encoded by TCF3) significantly enhanced E-box-dependent transcription. Furthermore, Ccndbp1 physically associated with MyoD but not E47. These data suggest that Ccndbp1 regulates muscle differentiation by interacting with MyoD and enhancing its binding to target genes. Our study newly identifies Ccndbp1 as a positive modulator of skeletal myogenic differentiation in vivo and in vitro, providing new insights in order to decipher the complex network involved in skeletal myogenic development and related diseases.
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Affiliation(s)
- Yan Huang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China Collaborative Innovation Center for Cancer Medicine, Guangzhou Key Laboratory of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Bohong Chen
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China
| | - Miaoman Ye
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China
| | - Puping Liang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China
| | - Yingnan Zhangfang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China
| | - Junjiu Huang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhou Songyang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China Collaborative Innovation Center for Cancer Medicine, Guangzhou Key Laboratory of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Wenbin Ma
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 51006, China Collaborative Innovation Center for Cancer Medicine, Guangzhou Key Laboratory of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
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McLellan AS, Langlands K, Kealey T. Exhaustive identification of human class II basic helix-loop-helix proteins by virtual library screening. Mech Dev 2016; 119 Suppl 1:S285-91. [PMID: 14516699 DOI: 10.1016/s0925-4773(03)00130-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cellular proliferation, specification and differentiation in developing tissues are tightly coordinated by groups of transcription factors in response to extrinsic and intrinsic signals. Furthermore, renewable pools of stem cells in adult tissues are subject to similar regulation. Basic helix-loop-helix (bHLH) proteins are a group of transcription factors that exert such a determinative influence on a variety of developmental pathways from C. elegans to humans, and we wished to exclusively identify novel members from within the whole human bHLH family. We have, therefore, developed an 'empirical custom fingerprint', to define the class II bHLH domain and exclusively identify these proteins in silico. We have identified nine previously uncharacterised human class II proteins, four of which were novel, by interrogating conceptual translations of the GenBank HTGS database. RT-PCR and mammalian 2-hybrid analysis of a subset of the factors demonstrated that they were indeed expressed, and were able to interact with an appropriate binding partner in vitro. Thus, we are now approaching an almost complete listing of human class II bHLH factors.
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Affiliation(s)
- Andrew S McLellan
- Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QR, UK.
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17
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Sabillo A, Ramirez J, Domingo CR. Making muscle: Morphogenetic movements and molecular mechanisms of myogenesis in Xenopus laevis. Semin Cell Dev Biol 2016; 51:80-91. [PMID: 26853935 DOI: 10.1016/j.semcdb.2016.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/01/2016] [Indexed: 12/15/2022]
Abstract
Xenopus laevis offers unprecedented access to the intricacies of muscle development. The large, robust embryos make it ideal for manipulations at both the tissue and molecular level. In particular, this model system can be used to fate map early muscle progenitors, visualize cell behaviors associated with somitogenesis, and examine the role of signaling pathways that underlie induction, specification, and differentiation of muscle. Several characteristics that are unique to X. laevis include myogenic waves with distinct gene expression profiles and the late formation of dermomyotome and sclerotome. Furthermore, myogenesis in the metamorphosing frog is biphasic, facilitating regeneration studies. In this review, we describe the morphogenetic movements that shape the somites and discuss signaling and transcriptional regulation during muscle development and regeneration. With recent advances in gene editing tools, X. laevis remains a premier model organism for dissecting the complex mechanisms underlying the specification, cell behaviors, and formation of the musculature system.
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Affiliation(s)
- Armbien Sabillo
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Julio Ramirez
- Department of Biology, San Francisco State University, CA 94132, USA
| | - Carmen R Domingo
- Department of Biology, San Francisco State University, CA 94132, USA.
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18
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The basic helix-loop-helix transcription factor E47 reprograms human pancreatic cancer cells to a quiescent acinar state with reduced tumorigenic potential. Pancreas 2015; 44:718-27. [PMID: 25894862 PMCID: PMC4464938 DOI: 10.1097/mpa.0000000000000328] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Pancreatic ductal adenocarcinoma (PDA) initiates from quiescent acinar cells that attain a Kras mutation, lose signaling from basic helix-loop-helix (bHLH) transcription factors, undergo acinar-ductal metaplasia, and rapidly acquire increased growth potential. We queried whether PDA cells can be reprogrammed to revert to their original quiescent acinar cell state by shifting key transcription programs. METHODS Human PDA cell lines were engineered to express an inducible form of the bHLH protein E47. Gene expression, growth, and functional studies were investigated using microarray, quantitative polymerase chain reaction, immunoblots, immunohistochemistry, small interfering RNA, chromatin immunoprecipitation analyses, and cell transplantation into mice. RESULTS In human PDA cells, E47 activity triggers stable G0/G1 arrest, which requires the cyclin-dependent kinase inhibitor p21 and the stress response protein TP53INP1. Concurrently, E47 induces high level expression of acinar digestive enzymes and feed forward activation of the acinar maturation network regulated by the bHLH factor MIST1. Moreover, induction of E47 in human PDA cells in vitro is sufficient to inhibit tumorigenesis. CONCLUSIONS Human PDA cells retain a high degree of plasticity, which can be exploited to induce a quiescent acinar cell state with reduced tumorigenic potential. Moreover, bHLH activity is a critical node coordinately regulating human PDA cell growth versus cell fate.
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McCoy CR, Stadelman BS, Brumaghim JL, Liu JT, Bain LJ. Arsenic and Its Methylated Metabolites Inhibit the Differentiation of Neural Plate Border Specifier Cells. Chem Res Toxicol 2015; 28:1409-21. [PMID: 26024302 DOI: 10.1021/acs.chemrestox.5b00036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Exposure to arsenic in food and drinking water has been correlated with adverse developmental outcomes, such as reductions in birth weight and neurological deficits. Additionally, studies have shown that arsenic suppresses sensory neuron formation and skeletal muscle myogenesis, although the reason why arsenic targets both of these cell types in unclear. Thus, P19 mouse embryonic stem cells were used to investigate the mechanisms by which arsenic could inhibit cellular differentiation. P19 cells were exposed to 0, 0.1, or 0.5 μM sodium arsenite and induced to form embryoid bodies over a period of 5 days. The expression of transcription factors necessary to form neural plate border specifier (NPBS) cells, neural crest cells and their progenitors, and myocytes and their progenitors were examined. Early during differentiation, arsenic significantly reduced the transcript and protein expression of Msx1 and Pax3, both needed for NPBS cell formation. Arsenic also significantly reduced the protein expression of Sox 10, needed for neural crest progenitor cell production, by 31-50%, and downregulated the protein and mRNA levels of NeuroD1, needed for neural crest cell differentiation, in a time- and dose-dependent manner. While the overall protein expression of transcription factors in the skeletal muscle lineage was not changed, arsenic did alter their nuclear localization. MyoD nuclear translocation was significantly reduced on days 2-5 between 15 and 70%. At a 10-fold lower concentration, monomethylarsonous acid (MMA III) appeared to be just as potent as inorganic arsenic at reducing the mRNA levels Pax3 (79% vs84%), Sox10 (49% vs 65%), and Msx1 (56% vs 56%). Dimethylarsinous acid (DMA III) also reduced protein and transcript expression, but the changes were less dramatic than those with MMA or arsenite. All three arsenic species reduced the nuclear localization of MyoD and NeuroD1 in a similar manner. The early changes in the differentiation of neural plate border specifier cells may provide a mechanism for arsenic to suppress both neurogenesis and myogenesis.
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Affiliation(s)
- Christopher R McCoy
- †Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, South Carolina 29634, United States
| | - Bradley S Stadelman
- ‡Department of Chemistry, Clemson University, 219 Hunter Laboratories, Clemson, South Carolina 29634, United States
| | - Julia L Brumaghim
- ‡Department of Chemistry, Clemson University, 219 Hunter Laboratories, Clemson, South Carolina 29634, United States
| | - Jui-Tung Liu
- §Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, South Carolina 29634, United States
| | - Lisa J Bain
- †Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, South Carolina 29634, United States.,§Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, South Carolina 29634, United States
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20
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Sciorati C, Clementi E, Manfredi AA, Rovere-Querini P. Fat deposition and accumulation in the damaged and inflamed skeletal muscle: cellular and molecular players. Cell Mol Life Sci 2015; 72:2135-56. [PMID: 25854633 PMCID: PMC11113943 DOI: 10.1007/s00018-015-1857-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 02/09/2015] [Accepted: 02/11/2015] [Indexed: 12/16/2022]
Abstract
The skeletal muscle has the capacity to repair damage by the activation and differentiation of fiber sub-laminar satellite cells. Regeneration impairment due to reduced satellite cells number and/or functional capacity leads to fiber substitution with ectopic tissues including fat and fibrous tissue and to the loss of muscle functions. Muscle mesenchymal cells that in physiological conditions sustain or directly contribute to regeneration differentiate in adipocytes in patients with persistent damage and inflammation of the skeletal muscle. These cells comprise the fibro-adipogenic precursors, the PW1-expressing cells and some interstitial cells associated with vessels (pericytes, mesoangioblasts and myoendothelial cells). Resident fibroblasts that are responsible for collagen deposition and extracellular matrix remodeling during regeneration yield fibrotic tissue and can differentiate into adipose cells. Some authors have also proposed that satellite cells themselves could transdifferentiate into adipocytes, although recent results by lineage tracing techniques seem to put this theory to discussion. This review summarizes findings about muscle resident mesenchymal cell differentiation in adipocytes and recapitulates the molecular mediators involved in intramuscular adipose tissue deposition.
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Affiliation(s)
- Clara Sciorati
- Division of Regenerative Medicine, Stem Cells and Gene Therapy, San Raffaele Scientific Institute, via Olgettina 58, 20132, Milan, Italy,
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21
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The basic helix-loop-helix (bHLH) transcription factor DEC2 negatively regulates Twist1 through an E-box element. Biochem Biophys Res Commun 2014; 455:390-5. [PMID: 25446074 DOI: 10.1016/j.bbrc.2014.11.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/11/2014] [Indexed: 11/20/2022]
Abstract
Differentiated embryo chondrocyte 2 (DEC2/Sharp-1/Bhlhe41), a basic helix-loop-helix (bHLH) transcription factor, has been shown to regulate the transcription of target genes by binding to their E-box elements. We identified a possible DEC2-response element (consensus E-box: CACGTG) in the promoter region of Twist1. Forced expression of DEC2 significantly repressed Twist1 promoter activity under normoxia and under hypoxia as assessed by a luciferase reporter assay. In addition, over-expression of DEC2 repressed Twist1 mRNA expression assessed by quantitative real-time PCR. Site-directed mutagenesis studies showed that mutagenesis of the consensus E-box sequence eliminated the ability of DEC2 to reduce the Twist1 promoter activity. Chromatin immunoprecipitation (ChIP) assays confirmed that the DEC2-mediated repression is primarily achieved by binding to the E-box in the Twist1 promoter. Knockdown of DEC2 by siRNA significantly attenuated the repression of Twist1 expression. DEC2 and Twist1 exhibit inversed protein expression patterns during development of mouse tongue embryo tissue. Given the fact that DEC2 protein is emerging as an important regulator in a vast array of cellular events, including cell differentiation, maturation of lymphocytes and the molecular clock, our study elucidates an important mechanism by which DEC2 regulates cellular function by modulating the expression of Twist1.
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22
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Johnson CL, Mehmood R, Laing SW, Stepniak CV, Kharitonenkov A, Pin CL. Silencing of the Fibroblast growth factor 21 gene is an underlying cause of acinar cell injury in mice lacking MIST1. Am J Physiol Endocrinol Metab 2014; 306:E916-28. [PMID: 24549397 DOI: 10.1152/ajpendo.00559.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fibroblast growth factor 21 (FGF21) is a key regulator of metabolism under conditions of stress such as starvation, obesity, and hypothermia. Rapid induction of FGF21 is also observed in experimental models of pancreatitis, and FGF21 reduces tissue damage observed in these models, suggesting a nonmetabolic function. Pancreatitis is a debilitating disease with significant morbidity that greatly increases the risk of pancreatic ductal adenocarcinoma. The goals of this study were to examine the regulation and function of FGF21 in acinar cell injury, specifically in a mouse model of pancreatic injury (Mist1(-/-)). Mist1(-/-) mice exhibit acinar cell disorganization, decreased acinar cell communication and exocytosis, and increased sensitivity to cerulein-induced pancreatitis (CIP). Examination of Fgf21 expression in Mist1(-/-) mice by qRT-PCR, Northern blot, and Western blot analyses showed a marked decrease in pancreatic Fgf21 expression before and after induction of CIP compared with C57Bl/6 mice. To determine whether the loss of FGF21 accounted for the Mist1(-/-) phenotypes, we generated Mist1(-/-) mice overexpressing human FGF21 from the ApoE promoter (Mist1(-/-)ApoE-FGF21). Reexpression of FGF21 partially mitigated pancreatic damage in Mist1(-/-) tissue based on reduced intrapancreatic enzyme activation, reduced expression of genes involved in fibrosis, and restored cell-cell junctions. Interestingly, alteration of Fgf21 expression in Mist1(-/-) tissue was not simply due to a loss of direct transcriptional regulation by MIST1. Chromatin immunopreciptation indicated that the loss of Fgf21 in the Mist1(-/-) pancreas is due, in part, to epigenetic silencing. Thus, our studies identify a new role for FGF21 in reducing acinar cell injury and uncover a novel mechanism for regulating Fgf21 gene expression.
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23
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Kommagani R, Szwarc MM, Kovanci E, Creighton CJ, O'Malley BW, Demayo FJ, Lydon JP. A murine uterine transcriptome, responsive to steroid receptor coactivator-2, reveals transcription factor 23 as essential for decidualization of human endometrial stromal cells. Biol Reprod 2014; 90:75. [PMID: 24571987 DOI: 10.1095/biolreprod.114.117531] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recent data from human and mouse studies strongly support an indispensable role for steroid receptor coactivator-2 (SRC-2)-a member of the p160/SRC family of coregulators-in progesterone-dependent endometrial stromal cell decidualization, an essential cellular transformation process that regulates invasion of the developing embryo into the maternal compartment. To identify the key progesterone-induced transcriptional changes that are dependent on SRC-2 and required for endometrial decidualization, we performed comparative genome-wide transcriptional profiling of endometrial tissue RNA from ovariectomized SRC-2(flox/flox) (SRC-2(f/f) [control]) and PR(cre/+)/SRC-2(flox/flox) (SRC-2(d/d) [SRC-2-depleted]) mice, acutely treated with vehicle or progesterone. Although data mining revealed that only a small subset of the total progesterone-dependent transcriptional changes is dependent on SRC-2 (∼13%), key genes previously reported to mediate progesterone-driven endometrial stromal cell decidualization are present within this subset. Along with providing a more detailed molecular portrait of the decidual transcriptional program governed by SRC-2, the degree of functional diversity of these progesterone mediators underscores the pleiotropic regulatory role of SRC-2 in this tissue. To showcase the utility of this powerful informational resource to uncover novel signaling paradigms, we stratified the total SRC-2-dependent subset of progesterone-induced transcriptional changes in terms of novel gene expression and identified transcription factor 23 (Tcf23), a basic-helix-loop-helix transcription factor, as a new progesterone-induced target gene that requires SRC-2 for full induction. Importantly, using primary human endometrial stromal cells in culture, we demonstrate that TCF23 function is essential for progesterone-dependent decidualization, providing crucial translational support for this transcription factor as a new decidual mediator of progesterone action.
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Affiliation(s)
- Ramakrishna Kommagani
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
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Abstract
Since the seminal discovery of the cell-fate regulator Myod, studies in skeletal myogenesis have inspired the search for cell-fate regulators of similar potential in other tissues and organs. It was perplexing that a similar transcription factor for other tissues was not found; however, it was later discovered that combinations of molecular regulators can divert somatic cell fates to other cell types. With the new era of reprogramming to induce pluripotent cells, the myogenesis paradigm can now be viewed under a different light. Here, we provide a short historical perspective and focus on how the regulation of skeletal myogenesis occurs distinctly in different scenarios and anatomical locations. In addition, some interesting features of this tissue underscore the importance of reconsidering the simple-minded view that a single stem cell population emerges after gastrulation to assure tissuegenesis. Notably, a self-renewing long-term Pax7+ myogenic stem cell population emerges during development only after a first wave of terminal differentiation occurs to establish a tissue anlagen in the mouse. How the future stem cell population is selected in this unusual scenario will be discussed. Recently, a wealth of information has emerged from epigenetic and genome-wide studies in myogenic cells. Although key transcription factors such as Pax3, Pax7, and Myod regulate only a small subset of genes, in some cases their genomic distribution and binding are considerably more promiscuous. This apparent nonspecificity can be reconciled in part by the permissivity of the cell for myogenic commitment, and also by new roles for some of these regulators as pioneer transcription factors acting on chromatin state.
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Affiliation(s)
- Glenda Comai
- Stem Cells and Development, CNRS URA 2578, Department of Developmental & Stem Cell Biology, Institut Pasteur, Paris, France
| | - Shahragim Tajbakhsh
- Stem Cells and Development, CNRS URA 2578, Department of Developmental & Stem Cell Biology, Institut Pasteur, Paris, France.
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25
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MacQuarrie KL, Yao Z, Fong AP, Tapscott SJ. Genome-wide binding of the basic helix-loop-helix myogenic inhibitor musculin has substantial overlap with MyoD: implications for buffering activity. Skelet Muscle 2013; 3:26. [PMID: 24175993 PMCID: PMC4177542 DOI: 10.1186/2044-5040-3-26] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 10/10/2013] [Indexed: 11/20/2022] Open
Abstract
Background Musculin (MSC) is a basic helix-loop-helix transcription factor that inhibits myogenesis during normal development and contributes to the differentiation defect in rhabdomyosarcoma. As one of many transcription factors that impede myogenesis, its binding on a genome-wide scale relative to the widespread binding of the myogenic factor MyoD is unknown. Methods Chromatin immunoprecipitation coupled to high-throughput sequencing was performed for endogenous MSC in rhabdomyosarcoma cells and its binding was compared to that of MyoD in the same type of cells. Results MSC binds throughout the genome, in a pattern very similar to MyoD. Its binding overlaps strongly with regions enriched for acetylated histone H4, as well as regions that score high for DNase hypersensitivity in human myoblasts. In contrast to MyoD, MSC has a more relaxed binding sequence preference in the nucleotides that flank the core E-box motif. Conclusions The myogenic inhibitor MSC binds throughout the genome of rhabdomyosarcoma cells, in a pattern highly similar to that of MyoD, suggesting a broad role in buffering the activity of MyoD in development and rhabdomyosarcomas.
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Affiliation(s)
- Kyle L MacQuarrie
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N C3-168, Seattle WA 98109, USA.,Molecular and Cellular Biology Program, University of Washington, Seattle WA 98105, USA
| | - Zizhen Yao
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N C3-168, Seattle WA 98109, USA
| | - Abraham P Fong
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle WA 98109, USA.,Department of Pediatrics, University of Washington School of Medicine, Seattle WA 98105, USA
| | - Stephen J Tapscott
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N C3-168, Seattle WA 98109, USA.,Department of Neurology, University of Washington, Seattle WA 98105, USA
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Hu D, Scott IC, Snider F, Geary-Joo C, Zhao X, Simmons DG, Cross JC. The basic helix-loop-helix transcription factor Hand1 regulates mouse development as a homodimer. Dev Biol 2013; 382:470-81. [PMID: 23911935 DOI: 10.1016/j.ydbio.2013.07.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 07/04/2013] [Accepted: 07/28/2013] [Indexed: 10/26/2022]
Abstract
Hand1 is a basic helix-loop-helix transcription factor that is essential for development of the placenta, yolk sac and heart during mouse development. While Hand1 is essential for trophoblast giant cell (TGC) differentiation, its potential heterodimer partners are not co-expressed in TGCs. To test the hypothesis that Hand1 functions as homodimer, we generated knock-in mice in which the Hand1 gene was altered to encode a tethered homodimer (TH). Some Hand1(TH/-) conceptuses in which the only form of Hand1 is Hand1(TH) are viable and fertile, indicating that homodimer Hand1 is sufficient for mouse survival. ~2/3 of Hand1(TH/-) and all Hand1(TH/TH) mice died in utero and displayed severe placental defects and variable cardial and cranial-facial abnormalities, indicating a dosage-dependent effect of Hand1(TH). Meanwhile, expression of the Hand1(TH) protein did not have negative effects on viability or fertility in all Hand1(TH/+) mice. These data imply that Hand1 homodimer plays a dominant role during development and its expression dosage is critical for survival, whereas Hand1 heterodimers can be either dispensable or play a regulatory role to modulate the activity of Hand1 homodimer in vivo.
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Affiliation(s)
- Dong Hu
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB, Canada; Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada; Center for Stem Cell Application and Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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27
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Abstract
Adult skeletal muscle in mammals is a stable tissue under normal circumstances but has remarkable ability to repair after injury. Skeletal muscle regeneration is a highly orchestrated process involving the activation of various cellular and molecular responses. As skeletal muscle stem cells, satellite cells play an indispensible role in this process. The self-renewing proliferation of satellite cells not only maintains the stem cell population but also provides numerous myogenic cells, which proliferate, differentiate, fuse, and lead to new myofiber formation and reconstitution of a functional contractile apparatus. The complex behavior of satellite cells during skeletal muscle regeneration is tightly regulated through the dynamic interplay between intrinsic factors within satellite cells and extrinsic factors constituting the muscle stem cell niche/microenvironment. For the last half century, the advance of molecular biology, cell biology, and genetics has greatly improved our understanding of skeletal muscle biology. Here, we review some recent advances, with focuses on functions of satellite cells and their niche during the process of skeletal muscle regeneration.
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Affiliation(s)
- Hang Yin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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28
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ZEB1 imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. Mol Cell Biol 2013; 33:1368-82. [PMID: 23339872 DOI: 10.1128/mcb.01259-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Skeletal muscle development is orchestrated by the myogenic regulatory factor MyoD, whose activity is blocked in myoblasts by proteins preventing its nuclear translocation and/or binding to G/C-centered E-boxes in target genes. Recent evidence indicates that muscle gene expression is also regulated at the cis level by differential affinity for DNA between MyoD and other E-box binding proteins during myogenesis. MyoD binds to G/C-centered E-boxes, enriched in muscle differentiation genes, in myotubes but not in myoblasts. Here, we used cell-based and in vivo Drosophila, Xenopus laevis, and mouse models to show that ZEB1, a G/C-centered E-box binding transcriptional repressor, imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. We found that, contrary to MyoD, ZEB1 binds to G/C-centered E-boxes in muscle differentiation genes at the myoblast stage but not in myotubes. Its knockdown results in precocious expression of muscle differentiation genes and acceleration of myotube formation. Inhibition of muscle genes by ZEB1 occurs via transcriptional repression and involves recruitment of the CtBP corepressor. Lastly, we show that the pattern of gene expression associated with muscle differentiation is accelerated in ZEB1(-/-) mouse embryos. These results set ZEB1 as an important regulator of the temporal pattern of gene expression controlling muscle differentiation.
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29
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Bharathy N, Ling BMT, Taneja R. Epigenetic regulation of skeletal muscle development and differentiation. Subcell Biochem 2013; 61:139-50. [PMID: 23150250 DOI: 10.1007/978-94-007-4525-4_7] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Skeletal muscle cells have served as a paradigm for understanding mechanisms leading to cellular differentiation. Formation of skeletal muscle involves a series of steps in which cells are committed towards the myogenic lineage, undergo expansion to give rise to myoblasts that differentiate into multinucleated myotubes, and mature to form adult muscle fibers. The commitment, proliferation, and differentiation of progenitor cells involve both genetic and epigenetic changes that culminate in alterations in gene expression. Members of the Myogenic regulatory factor (MRF), as well as the Myocyte Enhancer Factor (MEF2) families control distinct steps of skeletal muscle proliferation and differentiation. In addition, -growing evidence indicates that chromatin modifying enzymes and remodeling complexes epigenetically reprogram muscle promoters at various stages that preclude or promote MRF and MEF2 activites. Among these, histone deacetylases (HDACs), histone acetyltransferases (HATs), histone methyltransferases (HMTs) and SWI/SNF complexes alter chromatin structure through post-translational modifications to impact MRF and MEF2 activities. With such new and emerging knowledge, we are beginning to develop a true molecular understanding of the mechanisms by which skeletal muscle development and differentiation is regulated. Elucidation of the mechanisms by which epigenetic regulators control myogenesis will likely provide a new foundation for the development of novel therapeutic drugs for muscle dystrophies, ageing-related regeneration defects that occur due to altered proliferation and differentiation, and other malignancies.
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Affiliation(s)
- Narendra Bharathy
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Block MD9, 2 Medical Drive, Singapore, 117597, Singapore
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30
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Direnzo D, Hess DA, Damsz B, Hallett JE, Marshall B, Goswami C, Liu Y, Deering T, Macdonald RJ, Konieczny SF. Induced Mist1 expression promotes remodeling of mouse pancreatic acinar cells. Gastroenterology 2012; 143:469-80. [PMID: 22510200 PMCID: PMC3664941 DOI: 10.1053/j.gastro.2012.04.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/23/2012] [Accepted: 04/10/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND & AIMS Early embryogenesis involves cell fate decisions that define the body axes and establish pools of progenitor cells. Development does not stop once lineages are specified; cells continue to undergo specific maturation events, and changes in gene expression patterns lead to their unique physiological functions. Secretory pancreatic acinar cells mature postnatally to synthesize large amounts of protein, polarize, and communicate with other cells. The transcription factor MIST1 is expressed by only secretory cells and regulates maturation events. MIST1-deficient acinar cells in mice do not establish apical-basal polarity, properly position zymogen granules, or communicate with adjacent cells, disrupting pancreatic function. We investigated whether MIST1 directly induces and maintains the mature phenotype of acinar cells. METHODS We analyzed the effects of Cre-mediated expression of Mist1 in adult Mist1-deficient (Mist1(KO)) mice. Pancreatic tissues were collected and analyzed by light and electron microscopy, immunohistochemistry, real-time polymerase chain reaction analysis, and chromatin immunoprecipitation. Primary acini were isolated from mice and analyzed in amylase secretion assays. RESULTS Induced expression of Mist1 in adult Mist1(KO) mice restored wild-type gene expression patterns in acinar cells. The acinar cells changed phenotypes, establishing apical-basal polarity, increasing the size of zymogen granules, reorganizing the cytoskeletal network, communicating intercellularly (by synthesizing gap junctions), and undergoing exocytosis. CONCLUSIONS The exocrine pancreas of adult mice can be remodeled by re-expression of the transcription factor MIST1. MIST1 regulates acinar cell maturation and might be used to repair damaged pancreata in patients with pancreatic disorders.
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Affiliation(s)
- Daniel Direnzo
- Department of Biological Sciences and the Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - David A. Hess
- Department of Biological Sciences and the Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Barbara Damsz
- Department of Biological Sciences and the Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Judy E. Hallett
- Department of Biological Sciences and the Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Brett Marshall
- Department of Biological Sciences and the Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
| | - Chirayu Goswami
- Laboratory for Computational Genomics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Yunlong Liu
- Laboratory for Computational Genomics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Tye Deering
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Raymond J. Macdonald
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Stephen F. Konieczny
- Department of Biological Sciences and the Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana
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31
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Herreros-Villanueva M, Hijona E, Cosme A, Bujanda L. Mouse models of pancreatic cancer. World J Gastroenterol 2012; 18:1286-1294. [PMID: 22493542 PMCID: PMC3319955 DOI: 10.3748/wjg.v18.i12.1286] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 02/02/2012] [Accepted: 02/16/2012] [Indexed: 02/06/2023] Open
Abstract
Pancreatic cancer is one of the most lethal of human malignancies ranking 4th among cancer-related death in the western world and in the United States, and potent therapeutic options are lacking. Although during the last few years there have been important advances in the understanding of the molecular events responsible for the development of pancreatic cancer, currently specific mechanisms of treatment resistance remain poorly understood and new effective systemic drugs need to be developed and probed. In vivo models to study pancreatic cancer and approach this issue remain limited and present different molecular features that must be considered in the studies depending on the purpose to fit special research themes. In the last few years, several genetically engineered mouse models of pancreatic exocrine neoplasia have been developed. These models mimic the disease as they reproduce genetic alterations implicated in the progression of pancreatic cancer. Genetic alterations such as activating mutations in KRas, or TGFb and/or inactivation of tumoral suppressors such as p53, INK4A/ARF BRCA2 and Smad4 are the most common drivers to pancreatic carcinogenesis and have been used to create transgenic mice. These mouse models have a spectrum of pathologic changes, from pancreatic intraepithelial neoplasia to lesions that progress histologically culminating in fully invasive and metastatic disease and represent the most useful preclinical model system. These models can characterize the cellular and molecular pathology of pancreatic neoplasia and cancer and constitute the best tool to investigate new therapeutic approaches, chemopreventive and/or anticancer treatments. Here, we review and update the current mouse models that reproduce different stages of human pancreatic ductal adenocarcinoma and will have clinical relevance in future pancreatic cancer developments.
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Yang W, Itoh F, Ohya H, Kishimoto F, Tanaka A, Nakano N, Itoh S, Kato M. Interference of E2-2-mediated effect in endothelial cells by FAM96B through its limited expression of E2-2. Cancer Sci 2011; 102:1808-14. [DOI: 10.1111/j.1349-7006.2011.02022.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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Lelièvre EC, Lek M, Boije H, Houille-Vernes L, Brajeul V, Slembrouck A, Roger JE, Sahel JA, Matter JM, Sennlaub F, Hallböök F, Goureau O, Guillonneau X. Ptf1a/Rbpj complex inhibits ganglion cell fate and drives the specification of all horizontal cell subtypes in the chick retina. Dev Biol 2011; 358:296-308. [PMID: 21839069 DOI: 10.1016/j.ydbio.2011.07.033] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 07/19/2011] [Accepted: 07/25/2011] [Indexed: 11/18/2022]
Abstract
During development, progenitor cells of the retina give rise to six principal classes of neurons and the Müller glial cells found within the adult retina. The pancreas transcription factor 1 subunit a (Ptf1a) encodes a basic-helix-loop-helix transcription factor necessary for the specification of horizontal cells and the majority of amacrine cell subtypes in the mouse retina. The Ptf1a-regulated genes and the regulation of Ptf1a activity by transcription cofactors during retinogenesis have been poorly investigated. Using a retrovirus-mediated gene transfer approach, we reported that Ptf1a was sufficient to promote the fates of amacrine and horizontal cells from retinal progenitors and inhibit retinal ganglion cell and photoreceptor differentiation in the chick retina. Both GABAergic H1 and non-GABAergic H3 horizontal cells were induced following the forced expression of Ptf1a. We describe Ptf1a as a strong, negative regulator of Atoh7 expression. Furthermore, the Rbpj-interacting domains of Ptf1a protein were required for its effects on cell fate specification. Together, these data provide a novel insight into the molecular basis of Ptf1a activity on early cell specification in the chick retina.
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Affiliation(s)
- E C Lelièvre
- Centre de Recherche des Cordeliers, INSERM UMR S872, 75006 Paris, France
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Secretome Analysis of Skeletal Myogenesis Using SILAC and Shotgun Proteomics. INTERNATIONAL JOURNAL OF PROTEOMICS 2011; 2011:329467. [PMID: 22084683 PMCID: PMC3200090 DOI: 10.1155/2011/329467] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 01/26/2011] [Indexed: 12/18/2022]
Abstract
Myogenesis, the formation of skeletal muscle, is a multistep event that commences with myoblast proliferation, followed by cell-cycle arrest, and finally the formation of multinucleated myotubes via fusion of mononucleated myoblasts. Each step is orchestrated by well-documented intracellular factors, such as cytoplasmic signalling molecules and nuclear transcription factors. Regardless, the key step in getting a more comprehensive understanding of the regulation of myogenesis is to explore the extracellular factors that are capable of eliciting the downstream intracellular factors. This could further provide valuable insight into the acute cellular response to extrinsic cues in maintaining normal muscle development. In this paper, we survey the intracellular factors that respond to extracellular cues that are responsible for the cascades of events during myogenesis: myoblast proliferation, cell-cycle arrest of myoblasts, and differentiation of myoblasts into myotubes. This focus on extracellular perspective of muscle development illustrates our mass spectrometry-based proteomic approaches to identify differentially expressed secreted factors during skeletal myogenesis.
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35
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Saab R, Spunt SL, Skapek SX. Myogenesis and rhabdomyosarcoma the Jekyll and Hyde of skeletal muscle. Curr Top Dev Biol 2011; 94:197-234. [PMID: 21295688 DOI: 10.1016/b978-0-12-380916-2.00007-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rhabdomyosarcoma, a neoplasm composed of skeletal myoblast-like cells, represents the most common soft tissue sarcoma in children. The application of intensive chemotherapeutics and refined surgical and radiation therapy approaches have improved survival for children with localized disease over the past 3 decades; however, these approaches have not improved the dismal outcome for children with metastatic and recurrent rhabdomyosarcoma. Elegant studies have defined the molecular mechanisms driving skeletal muscle lineage commitment and differentiation, and the machinery that couples differentiation with irreversible cell proliferation arrest. Further, detailed molecular analyses indicate that rhabdomyosarcoma cells have lost the capacity to fully differentiate when challenged to do so in experimental models. We review the intersection of normal skeletal muscle developmental biology and the molecular genetic defects in rhabdomyosarcoma with the underlying premise that understanding how the differentiation process has gone awry will lead to new treatment strategies aimed at promoting myogenic differentiation and concomitant cell cycle arrest.
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Affiliation(s)
- Raya Saab
- Children's Cancer Center of Lebanon, Department of Pediatrics, American University of Beirut, Beirut, Lebanon
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36
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Capoccia BJ, Lennerz JKM, Bredemeyer AJ, Klco JM, Frater JL, Mills JC. Transcription factor MIST1 in terminal differentiation of mouse and human plasma cells. Physiol Genomics 2010; 43:174-86. [PMID: 21098683 DOI: 10.1152/physiolgenomics.00084.2010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite their divergent developmental ancestry, plasma cells and gastric zymogenic (chief) cells share a common function: high-capacity secretion of protein. Here we show that both cell lineages share increased expression of a cassette of 269 genes, most of which regulate endoplasmic reticulum (ER) and Golgi function, and they both induce expression of the transcription factors X-box binding protein 1 (Xbp1) and Mist1 during terminal differentiation. XBP1 is known to augment plasma cell function by establishing rough ER, and MIST1 regulates secretory vesicle trafficking in zymogenic cells. We examined morphology and function of plasma cells in wild-type and Mist1(-/-) mice and found subtle differences in ER structure but no overall defect in plasma cell function, suggesting that Mist1 may function redundantly in plasma cells. We next reasoned that MIST1 might be useful as a novel and reliable marker of plasma cells. We found that MIST1 specifically labeled normal plasma cells in mouse and human tissues, and, moreover, its expression was also characteristic of plasma cell differentiation in a cohort of 12 human plasma cell neoplasms. Overall, our results show that MIST1 is enriched upon plasma cell differentiation as a part of a genetic program facilitating secretory cell function and also that MIST1 is a novel marker of normal and neoplastic plasma cells in mouse and human tissues.
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Affiliation(s)
- Benjamin J Capoccia
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Cano A, Portillo F. An emerging role for class I bHLH E2-2 proteins in EMT regulation and tumor progression. Cell Adh Migr 2010; 4:56-60. [PMID: 20023376 DOI: 10.4161/cam.4.1.9995] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
EMT is a complex process whereby cells lose cell-cell interactions and other epithelial properties whilst acquiring a migratory and mesenchymal phenotype. EMT is presently recognized as an important even for tumor invasion and metastasis. Functional E-cadherin loss is a hallmark of EMT and required for tumor invasion in the majority of carcinomas. Transcriptional downregulation is one of the major mechanisms for E-cadherin suppression in carcinomas. In the last decade several E-cadherin repressors, belonging to different transcriptional families, have been identified that, importantly, also act as potent EMT inducers. One of the last additions to EMT regulators are the class I bHLH factors E2-2 (also known as TCF4). However, the hierarchical and functional interrelations between the different EMT inducers are still poorly understood. Here, we comment on the new and so far unrecognized function of E2-2 factors in EMT and discuss on the potential interactions among various EMT inducers. Emerging evidence supporting the participation of TCF4 in human malignancies is also discussed. Thus, increasing understanding of EMT and its regulators is providing meaningful insights into the present knowledge on tumor progression.
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Affiliation(s)
- Amparo Cano
- Departmento de Bioquímica, Universidad Autónoma de Madrid (UAM), Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Madrid, Spain.
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Sobrado VR, Moreno-Bueno G, Cubillo E, Holt LJ, Nieto MA, Portillo F, Cano A. The class I bHLH factors E2-2A and E2-2B regulate EMT. J Cell Sci 2009; 122:1014-24. [DOI: 10.1242/jcs.028241] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Functional loss of the cell-cell adhesion molecule E-cadherin is an essential event for epithelial-mesenchymal transition (EMT), a process that allows cell migration during embryonic development and tumour invasion. In most carcinomas, transcriptional repression has emerged as the main mechanism responsible for E-cadherin downregulation. Here, we report the identification of class I bHLH factor E2-2 (TCF4/ITF2) as a new EMT regulator. Both isoforms of E2-2 (E2-2A and E2-2B) induce a full EMT when overexpressed in MDCK cells but without affecting the tumorigenic properties of parental cells, in contrast to other EMT inducers, such as Snail1 or class I bHLH E47. E-cadherin repression mediated by E2-2 is indirect and independent of proximal E-boxes of the promoter. Knockdown studies indicate that E2-2 expression is dispensable for maintenance of the EMT driven by Snail1 and E47. Comparative gene-profiling analysis reveals that E2-2 factors induce similar, yet distinct, genetic programs to that induced by E47 in MDCK cells. These results, together with the embryonic expression pattern of Tcf4 and E2A (which encodes E12/E47), support a distinct role for E2-2 and suggest an interesting interplay between E-cadherin repressors in the regulation of physiological and pathological EMT processes.
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Affiliation(s)
- Verónica R. Sobrado
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Instituto de Investigaciones Biomédicas `Alberto Sols' (CSIC-UAM), 28029 Madrid, Spain
| | - Gema Moreno-Bueno
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Instituto de Investigaciones Biomédicas `Alberto Sols' (CSIC-UAM), 28029 Madrid, Spain
| | - Eva Cubillo
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Instituto de Investigaciones Biomédicas `Alberto Sols' (CSIC-UAM), 28029 Madrid, Spain
| | - Liam J. Holt
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Instituto de Investigaciones Biomédicas `Alberto Sols' (CSIC-UAM), 28029 Madrid, Spain
| | - M. Angela Nieto
- Instituto de Neurociencias de Alicante, CSIC-UMH, 03550 Sant Joan d'Alacant, Spain
| | - Francisco Portillo
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Instituto de Investigaciones Biomédicas `Alberto Sols' (CSIC-UAM), 28029 Madrid, Spain
| | - Amparo Cano
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), Instituto de Investigaciones Biomédicas `Alberto Sols' (CSIC-UAM), 28029 Madrid, Spain
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Wang Y, Chen KP, Yao Q. [Progress of studies on bHLH transcription factor families]. YI CHUAN = HEREDITAS 2009; 30:821-30. [PMID: 18779123 DOI: 10.3724/sp.j.1005.2008.00821] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
bHLH transcription factors are important players in various developmental processes of eukaryotes. They constitute a large family of transcription factors. bHLH family members have been identified in genomes of 20 organisms including 17 animals, two plants, and one yeast. Animal bHLHs are classified into 45 families based on their different functions in the regulation of gene expression. In addition, they are divided into 6 groups according to target DNA elements they bind and their own structural characteristics. Group A consists of 22 families. They mainly regulate neurogenesis, myogenesis and mesoderm formation. Group B consists of 12 families. They mainly regulate cell proliferation and differentiation, sterol metabolism and adipocyte formation, and expression of glucose-responsive genes. Group C has seven families. They are responsible for the regulation of midline and tracheal development, circadian rhythms, and for the activation of gene transcription in response to environmental toxins. Group D has only one family. It forms inactive heterodimers with group A bHLH proteins. Group E has two families, which regulate embryonic segmentation, somitogenesis and organogenesis etc. Group F also has one family. It regulates head development and formation of olfactory sensory neurons etc. This article presents a brief review on progress achieved in studies related to the classification, origination and functions of bHLH transcription factor families.
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Affiliation(s)
- Yong Wang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
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Park D, Veenstra JA, Park JH, Taghert PH. Mapping peptidergic cells in Drosophila: where DIMM fits in. PLoS One 2008; 3:e1896. [PMID: 18365028 PMCID: PMC2266995 DOI: 10.1371/journal.pone.0001896] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 02/22/2008] [Indexed: 11/24/2022] Open
Abstract
The bHLH transcription factor DIMMED has been associated with the differentiation of peptidergic cells in Drosophila. However, whether all Drosophila peptidergic cells express DIMM, and the extent to which all DIMM cells are peptidergic, have not been determined. To address these issues, we have mapped DIMM expression in the central nervous system (CNS) and periphery in the late larval stage Drosophila. At 100 hr after egg-laying, DIMM immunosignals are largely congruent with a dimm-promoter reporter (c929-GAL4) and they present a stereotyped pattern of 306 CNS cells and 52 peripheral cells. We assigned positional values for all DIMM CNS cells with respect to reference gene expression patterns, or to patterns of secondary neuroblast lineages. We could assign provisional peptide identities to 68% of DIMM-expressing CNS cells (207/306) and to 73% of DIMM-expressing peripheral cells (38/52) using a panel of 24 markers for Drosophila neuropeptide genes. Furthermore, we found that DIMM co-expression was a prevalent feature within single neuropeptide marker expression patterns. Of the 24 CNS neuropeptide gene patterns we studied, six patterns are >90% DIMM-positive, while 16 of 22 patterns are >40% DIMM-positive. Thus most or all DIMM cells in Drosophila appear to be peptidergic, and many but not all peptidergic cells express DIMM. The co-incidence of DIMM-expression among peptidergic cells is best explained by a hypothesis that DIMM promotes a specific neurosecretory phenotype we term LEAP. LEAP denotes Large cells that display Episodic release of Amidated Peptides.
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Affiliation(s)
- Dongkook Park
- Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | | | - Jae H. Park
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee–Knoxville, Knoxville, Tennessee, United States of America
| | - Paul H. Taghert
- Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
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The Drosophila basic helix-loop-helix protein DIMMED directly activates PHM, a gene encoding a neuropeptide-amidating enzyme. Mol Cell Biol 2007; 28:410-21. [PMID: 17967878 DOI: 10.1128/mcb.01104-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The basic helix-loop-helix (bHLH) protein DIMMED (DIMM) supports the differentiation of secretory properties in numerous peptidergic cells of Drosophila melanogaster. DIMM is coexpressed with diverse amidated neuropeptides and with the amidating enzyme peptidylglycine alpha-hydroxylating monooxygenase (PHM) in approximately 300 cells of the late embryo. Here we confirm that DIMM has transcription factor activity in transfected HEK 293 cells and that the PHM gene is a direct target. The mammalian DIMM orthologue MIST1 also transactivated the PHM gene. DIMM activity was dependent on the basic region of the protein and on the sequences of three E-box sites within PHM's first intron; the sites make different contributions to the total activity. These data suggest a model whereby the three E boxes interact cooperatively and independently to produce high PHM transcriptional activation. This DIMM-controlled PHM regulatory region displayed similar properties in vivo. Spatially, its expression mirrored that of the DIMM protein, and its activity was largely dependent on dimm. Further, in vivo expression was highly dependent on the sequences of the same three E boxes. This study supports the hypothesis that DIMM is a master regulator of a peptidergic cell fate in Drosophila and provides a detailed transcriptional mechanism of DIMM action on a defined target gene.
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Pin CL, Johnson CL, Rade B, Kowalik AS, Garside VC, Everest ME. Identification of a transcription factor, BHLHB8, involved in mouse seminal vesicle epithelium differentiation and function. Biol Reprod 2007; 78:91-100. [PMID: 17901072 DOI: 10.1095/biolreprod.107.064196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The seminal vesicle is a male accessory sex organ that develops from segments of the Wolffian duct adjacent to the urogenital sinus. It produces most of the seminal plasma in both humans and rodents. To date, very few transcription factors have been linked to the development and differentiation of seminal vesicles. In this study, we have examined the role of basic helix-loop-helix (BHLH) B8 transcription factor expressed at high levels in the adult seminal vesicle and during seminal gland differentiation. Immunofluorescent studies indicate that BHLHB8 is expressed within the epithelial layer of the seminal layer of the seminal vesicle following branching morphogenesis but prior to full maturation of cell morphology and function. Analysis of mice that do not express BHLHB8 (Bhlhb8(-/-)) indicates no deficiency in the initial development of the seminal vesicle. However, morphological and ultrastructural analysis indicates disruption of the epithelial cellular architecture. The seminal vesicle epithelial layer of 2-mo-old Bhlhb8(-/-) mice shows extensive cellular degeneration based on the appearance of reduced microvilli, altered granule size, and dilated endoplasmic reticulum and Golgi apparatus. The seminal vesicle epithelial cells also degenerate prematurely, as evidenced by disruption of nuclear architecture and significant accumulations of autophagic bodies. These results identify BHLHB8 as a regulator in establishing and stabilizing the secreting epithelial cells of the seminal vesicle.
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Affiliation(s)
- Christopher L Pin
- Department of Paediatrics, The University of Western Ontario, Children's Health Research Institute, London, ON, Canada.
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Acosta-Alvear D, Zhou Y, Blais A, Tsikitis M, Lents NH, Arias C, Lennon CJ, Kluger Y, Dynlacht BD. XBP1 controls diverse cell type- and condition-specific transcriptional regulatory networks. Mol Cell 2007; 27:53-66. [PMID: 17612490 DOI: 10.1016/j.molcel.2007.06.011] [Citation(s) in RCA: 654] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 06/04/2007] [Accepted: 06/13/2007] [Indexed: 01/18/2023]
Abstract
Using genome-wide approaches, we have elucidated the regulatory circuitry governed by the XBP1 transcription factor, a key effector of the mammalian unfolded protein response (UPR), in skeletal muscle and secretory cells. We identified a core group of genes involved in constitutive maintenance of ER function in all cell types and tissue- and condition-specific targets. In addition, we identified a cadre of unexpected targets that link XBP1 to neurodegenerative and myodegenerative diseases, as well as to DNA damage and repair pathways. Remarkably, we found that XBP1 regulates functionally distinct targets through different sequence motifs. Further, we identified Mist1, a critical regulator of differentiation, as an important target of XBP1, providing an explanation for developmental defects associated with XBP1 loss of function. Our results provide a detailed picture of the regulatory roadmap governed by XBP1 in distinct cell types as well as insight into unexplored functions of XBP1.
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Guo X, Cheng L, Liu Y, Fan W, Lu D. Cloning, expression, and functional characterization of zebrafish Mist1. Biochem Biophys Res Commun 2007; 359:20-6. [PMID: 17531198 DOI: 10.1016/j.bbrc.2007.05.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 05/06/2007] [Indexed: 11/16/2022]
Abstract
The basic helix-loop-helix (bHLH) protein Mist1 is an important exocrine pancreas transcriptional factor expressed in the acinar cells of mammals. In the present study, we cloned the homologous Mist1 cDNA encoding a predicted protein of 184 amino acids in zebrafish. The typical bHLH domain of zebrafish Mist1 shares high identity with that of its orthologs in mouse, rat, and human. Expression analysis revealed that Mist1 maternal transcripts are distinct in the very beginning of embryogenesis and that endogenous Mist1 is chronologically expressed in polster, hatching gland, hindbrain and appears exclusively in the pancreas from 72 hpf onward. Knockdown of Mist1 conditionally causes mild morphological defects in embryos. In MO-treated embryos, midbrain-hindbrain boundary is missing and exocrine pancreas is significantly reduced and disorganized. These results suggest that Mist1 functions in an evolutionary conserved way as a key transcriptional regulator specific for exocrine pancreas development in zebrafish.
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Affiliation(s)
- Xiaofang Guo
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, PR China
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Abstract
Mist1 is a tissue-specific basic helix-loop-helix (bHLH) transcription factor that plays an essential role in maintaining and organizing the exocrine pancreas. Consequently, mice lacking Mist1 exhibit disrupted acinar cellular polarity and defective zymogen granule trafficking. Despite extensive studies demonstrating a requirement for Mist1 in exocrine pancreas development and function, little is known about the molecular targets for Mist1 interaction and the mechanism(s) of how Mist1 regulates gene transcription. To address these deficiencies, a series of molecular studies was performed to identify the preferred Mist1 dimer complex and to establish the preferred DNA binding site for this bHLH factor. In vivo coimmunoprecipitation assays confirmed that the functional Mist1 complex in pancreatic acinar cells was a Mist1 homodimer that bound to a unique DNA target site known as the TA-E-box. Binding of Mist1 to a TA-E-box-regulated promoter led to transcriptional activation of the target gene. Surprisingly, Mist1 truncations containing only the central bHLH domain retained approximately 80% of transcriptional activity. Coimmunoprecipitation studies demonstrated that the bHLH domain interacted with coactivators belonging to the p300/CBP family, suggesting that Mist1 activates exocrine-specific gene transcription through an acetylation mechanism.
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Affiliation(s)
- Thai Tran
- Department of Biological Sciences and the Purdue Cancer Center, Purdue University, West Lafayette, IN, USA
| | - Di Jia
- Department of Biological Sciences and the Purdue Cancer Center, Purdue University, West Lafayette, IN, USA
| | - Yan Sun
- Department of Biological Sciences and the Purdue Cancer Center, Purdue University, West Lafayette, IN, USA
| | - Stephen F. Konieczny
- Department of Biological Sciences and the Purdue Cancer Center, Purdue University, West Lafayette, IN, USA
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Zhao Y, Johansson C, Tran T, Bettencourt R, Itahana Y, Desprez PY, Konieczny SF. Identification of a basic helix-loop-helix transcription factor expressed in mammary gland alveolar cells and required for maintenance of the differentiated state. Mol Endocrinol 2006; 20:2187-98. [PMID: 16645041 DOI: 10.1210/me.2005-0214] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The development of mammary glands relies on complicated signaling pathways that control cell proliferation, differentiation, and apoptotic events through transcriptional regulatory circuits. A key family of transcription factors used in mammary gland development is the helix-loop-helix/basic helix-loop-helix (HLH/bHLH) protein family. In this study, we identify Mist1 as a tissue-restricted Class II bHLH transcription factor expressed in lactating mammary glands. Mouse and human mammary glands accumulated Mist1 protein exclusively in secretory alveolar cells, and Mist1 transcripts were differentially expressed in mouse SCp2 cells induced to differentiate by addition of lactogenic hormones. Mist1 null (Mist1(KO)) lactating mammary glands were defective in normal lobuloalveolar organization, exhibiting shedding of cells into the alveolus lumen and premature activation of the signal transducer and activator of transcription 3 signaling pathway. These cells also failed to maintain expression of the gap junction proteins connexin26 and connexin32, leading to the loss of gap junctions. Our findings suggest that loss of Mist1 impairs the maintenance of the fully differentiated alveolar state and, for the first time, places Mist1 within the hierarchy of known HLH/bHLH proteins that control mammary epithelial cell development.
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Affiliation(s)
- Yan Zhao
- Department of Biological Sciences and the Purdue Cancer Center, Purdue University, West Lafayette, Indiana 47907-2064, USA
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Tuveson DA, Zhu L, Gopinathan A, Willis NA, Kachatrian L, Grochow R, Pin CL, Mitin NY, Taparowsky EJ, Gimotty PA, Hruban RH, Jacks T, Konieczny SF. Mist1-KrasG12D knock-in mice develop mixed differentiation metastatic exocrine pancreatic carcinoma and hepatocellular carcinoma. Cancer Res 2006; 66:242-7. [PMID: 16397237 DOI: 10.1158/0008-5472.can-05-2305] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite the prevalence of oncogenic Kras mutations in the earliest stages of pancreatic ductal adenocarcinoma, the cellular compartment in which oncogenic Kras initiates tumorigenesis remains unknown. To address this, we have gene targeted KrasG12D into the open reading frame of Mist1, a basic helix-loop-helix transcription factor that is expressed during pancreatic development and required for proper pancreatic acinar organization. Although the pancreata of Mist1(KrasG12D/+) mutant mice predictably exhibited acinar metaplasia and dysplasia, the frequent death of these mice from invasive and metastatic pancreatic cancer with mixed histologic characteristics, including acinar, cystic, and ductal features, was unexpected and in contrast to previously described mutant mice that ectopically expressed the Kras oncogene in either acinar or ductal compartments. Interestingly, many of the mutant mice developed hepatocellular carcinoma, implicating Mist1(KrasG12D/+) cells in both pancreatic and hepatic neoplasia. Concomitant Trp53+/- mutation cooperated with Mist1(KrasG12D/+) to accelerate lethality and was associated with advanced histopathologic findings, including parenchymal liver metastasis. These findings suggest that Mist1-expressing cells represent a permissive compartment for transformation by oncogenic Kras in pancreatic tumorigenesis.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Transcription Factors/genetics
- Basic Helix-Loop-Helix Transcription Factors/metabolism
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/metabolism
- Carcinoma, Pancreatic Ductal/pathology
- Genes, p53/genetics
- Genes, ras/genetics
- Liver Neoplasms, Experimental/genetics
- Liver Neoplasms, Experimental/metabolism
- Liver Neoplasms, Experimental/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neoplasm Metastasis
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/metabolism
- Pancreatic Neoplasms/pathology
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Affiliation(s)
- David A Tuveson
- Department of Medicine, Abramson Family Cancer Research Institute, Philadelphia, Pennsylvania, USA.
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Jethanandani P, Kramer RH. Alpha7 integrin expression is negatively regulated by deltaEF1 during skeletal myogenesis. J Biol Chem 2005; 280:36037-46. [PMID: 16129691 DOI: 10.1074/jbc.m508698200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alpha7 integrin levels increase dramatically as myoblasts differentiate to myotubes. A negative regulatory element with putative sites for deltaEF1 is present in the alpha7 proximal promoter region. To define the role of deltaEF1 in regulating alpha7 integrin expression, we overexpressed deltaEF1 in C2C12 myoblasts. This resulted in a major down-regulation of alpha7 protein expression. Promoter assays revealed that C2C12 myoblasts transfected with deltaEF1 showed a decrease in activity of the 2.8-kb alpha7 promoter fragment, indicating regulation of alpha7 integrin at the transcriptional level. We have identified two E-box-like sites for deltaEF1 in the negative regulatory region. Mutation of these sites enhanced alpha7 promoter activity, indicating that these sites function in repression. MYOD, an activator of alpha7 integrin transcription, can compete with deltaEF1 for binding at these sites in gel shift assay. By using chromatin immunoprecipitation, we demonstrated a reciprocal binding of deltaEF1 and MYOD to this regulatory element depending on the stage of differentiation: deltaEF1 is preferentially bound in myoblasts to this region, whereas MYOD is bound in myotubes. The N-terminal region of deltaEF1 is necessary for alpha7 repression, and this region also binds the co-activator p300/CBP. Importantly, we found that the p300/CBP co-activator can overcome repression by deltaEF1, suggesting that deltaEF1 can titrate limiting amounts of this co-activator. These findings suggest that deltaEF1 has a role in suppressing integrin expression in myoblasts by displacing MYOD and competing for p300/CBP co-activator.
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Affiliation(s)
- Poonam Jethanandani
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143-0640, USA
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Abstract
The basic helix-loop-helix myogenic regulatory factors MyoD, Myf5, myogenin and MRF4 have critical roles in skeletal muscle development. Together with the Mef2 proteins and E proteins, these transcription factors are responsible for coordinating muscle-specific gene expression in the developing embryo. This review highlights recent studies regarding the molecular mechanisms by which the muscle-specific myogenic bHLH proteins interact with other regulatory factors to coordinate gene expression in a controlled and ordered manner.
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Yu L, Sangster N, Perez A, McCormick PJ. The bHLH protein MyoR inhibits the differentiation of early embryonic endoderm. Differentiation 2005; 72:341-7. [PMID: 15554945 DOI: 10.1111/j.1432-0436.2004.07207005.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
MyoR is a bHLH protein whose expression was reported to be almost exclusively restricted to the precursors of the skeletal muscle lineage where it was postulated to function as a transcriptional repressor of myogenesis. However, previous studies in our laboratory suggested a much broader role for MyoR in embryonic cell differentiation. We demonstrated that, besides being expressed in several adult tissues of non-muscle lineage, MyoR was expressed at a much earlier stage in mammalian development than had previously been reported, that is, as early as the blastocyst stage, well before skeletal muscle specification. We also found that, as in skeletal muscle precursor cells, MyoR expression is inversely correlated with the cellular differentiative state of ectodermal, non-muscle embryonal carcinoma (EC) cells. Retinoic acid (RA) treatment of ectodermal EC or embryonal stem (ES) cells promotes their differentiation into primitive endoderm. However, in the present study, we show that the RA-induced expression of endodermal markers such as EndoA, collagen IV, and t-PA are inhibited by exogenous MyoR expression and that the level of inhibition of these markers correlates with the level of MyoR expressed. Conversely, knock-down of MyoR expression via RNA interference enhances RA-induced differentiation of EC cells, promoting earlier and much higher expression of the above-mentioned endodermal markers following RA treatment. Finally, we have narrowed the period of exogenous MyoR-induced embryonic lethality to between 3.5 and 5.5 days post-coitum (dpc), the period during which embryonic endoderm differentiates from the embryonic ectoderm. Our results suggest, therefore, that inhibition of endodermal differentiation between 3.5 and 5.5 dpc contributes to the embryonic death of mouse embryos overexpressing exogenous MyoR and consequently that MyoR may serve as a repressor of embryonal endoderm differentiation.
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Affiliation(s)
- Liming Yu
- Center for Functional Genomics, The University at Albany, State University of New York, One University Place, East Campus A202, Rensselaer, NY 12144, USA
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