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Architha TCA, Juanitaa GR, Vijayalalitha R, Jayasuriya R, Athira G, Balamurugan R, Ganesan K, Ramkumar KM. LncRNA NEAT1/miR-146a-5p Axis Restores Normal Angiogenesis in Diabetic Foot Ulcers by Targeting mafG. Cells 2024; 13:456. [PMID: 38474419 PMCID: PMC10931324 DOI: 10.3390/cells13050456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/23/2024] [Accepted: 02/28/2024] [Indexed: 03/14/2024] Open
Abstract
Non-healing lesions in diabetic foot ulcers are a significant effect of poor angiogenesis. Epigenetic regulators, mainly lncRNA and miRNA, are recognized for their important roles in disease progression. We deciphered the regulation of lncRNA NEAT1 through the miR-146a-5p/mafG axis in the progression of DFU. A lowered expression of lncRNA NEAT1 was associated with dysregulated angiogenesis through the reduced expression of mafG, SDF-1α, and VEGF in chronic ulcer subjects compared to acute DFU. This was validated by silencing NEAT1 by SiRNA in the endothelial cells which resulted in the transcriptional repression of target genes. Our in silico analysis identified miR-146a-5p as a potential target of lncRNA NEAT1. Further, silencing NEAT1 led to an increase in the levels of miR-146a-5p in chronic DFU subjects. This research presents the role of the lncRNA NEAT1/miR-146a-5p/mafG axis in enhancing angiogenesis in DFU.
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Affiliation(s)
- TCA Architha
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Chengalpattu Dt., Tamil Nadu, India; (T.A.); (G.R.J.); (R.V.); or (R.J.)
| | - George Raj Juanitaa
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Chengalpattu Dt., Tamil Nadu, India; (T.A.); (G.R.J.); (R.V.); or (R.J.)
| | - Ramanarayanan Vijayalalitha
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Chengalpattu Dt., Tamil Nadu, India; (T.A.); (G.R.J.); (R.V.); or (R.J.)
| | - Ravichandran Jayasuriya
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Chengalpattu Dt., Tamil Nadu, India; (T.A.); (G.R.J.); (R.V.); or (R.J.)
| | - Gopinathan Athira
- SRM Medical Hospital and Research Centre, SRM Institute of Science and Technology, Kattankulathur 603 203, Chengalpattu Dt., Tamil Nadu, India; (G.A.); (R.B.)
| | - Ramachandran Balamurugan
- SRM Medical Hospital and Research Centre, SRM Institute of Science and Technology, Kattankulathur 603 203, Chengalpattu Dt., Tamil Nadu, India; (G.A.); (R.B.)
| | - Kumar Ganesan
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong 999077, China
| | - Kunka Mohanram Ramkumar
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Chengalpattu Dt., Tamil Nadu, India; (T.A.); (G.R.J.); (R.V.); or (R.J.)
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Deng Y, Lu L, Zhang H, Fu Y, Liu T, Chen Y. The role and regulation of Maf proteins in cancer. Biomark Res 2023; 11:17. [PMID: 36750911 PMCID: PMC9903618 DOI: 10.1186/s40364-023-00457-w] [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: 08/25/2022] [Accepted: 01/22/2023] [Indexed: 02/09/2023] Open
Abstract
The Maf proteins (Mafs) belong to basic leucine zipper transcription factors and are members of the activator protein-1 (AP-1) superfamily. There are two subgroups of Mafs: large Mafs and small Mafs, which are involved in a wide range of biological processes, such as the cell cycle, proliferation, oxidative stress, and inflammation. Therefore, dysregulation of Mafs can affect cell fate and is closely associated with diverse diseases. Accumulating evidence has established both large and small Mafs as mediators of tumor development. In this review, we first briefly describe the structure and physiological functions of Mafs. Then we summarize the upstream regulatory mechanisms that control the expression and activity of Mafs. Furthermore, we discuss recent studies on the critical role of Mafs in cancer progression, including cancer proliferation, apoptosis, metastasis, tumor/stroma interaction and angiogenesis. We also review the clinical implications of Mafs, namely their potential possibilities and limitations as biomarkers and therapeutic targets in cancer.
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Affiliation(s)
- Yalan Deng
- grid.452223.00000 0004 1757 7615Department of Oncology, NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan China
| | - Liqing Lu
- grid.452223.00000 0004 1757 7615Department of Oncology, NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan China ,grid.452223.00000 0004 1757 7615Department of Thoracic Surgery, Xiangya Hospital, Central South University, Changsha, 410008 Hunan China
| | - Huajun Zhang
- grid.452223.00000 0004 1757 7615Department of Oncology, NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan China ,grid.452223.00000 0004 1757 7615Department of Ultrasonic Imaging, Xiangya Hospital, Central South University, Changsha, 410008 Hunan China
| | - Ying Fu
- grid.452223.00000 0004 1757 7615Department of Oncology, NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan China
| | - Ting Liu
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
| | - Yongheng Chen
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China. .,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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Patel SD, Anand D, Motohashi H, Katsuoka F, Yamamoto M, Lachke SA. Deficiency of the bZIP transcription factors Mafg and Mafk causes misexpression of genes in distinct pathways and results in lens embryonic developmental defects. Front Cell Dev Biol 2022; 10:981893. [PMID: 36092713 PMCID: PMC9459095 DOI: 10.3389/fcell.2022.981893] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/28/2022] [Indexed: 01/11/2023] Open
Abstract
Deficiency of the small Maf proteins Mafg and Mafk cause multiple defects, namely, progressive neuronal degeneration, cataract, thrombocytopenia and mid-gestational/perinatal lethality. Previous data shows Mafg -/-:Mafk +/- compound knockout (KO) mice exhibit cataracts age 4-months onward. Strikingly, Mafg -/-:Mafk -/- double KO mice develop lens defects significantly early in life, during embryogenesis, but the pathobiology of these defects is unknown, and is addressed here. At embryonic day (E)16.5, the epithelium of lens in Mafg -/-:Mafk -/- animals appears abnormally multilayered as demonstrated by E-cadherin and nuclear staining. Additionally, Mafg -/-:Mafk -/- lenses exhibit abnormal distribution of F-actin near the "fulcrum" region where epithelial cells undergo apical constriction prior to elongation and reorientation as early differentiating fiber cells. To identify the underlying molecular changes, we performed high-throughput RNA-sequencing of E16.5 Mafg -/-:Mafk -/- lenses and identified a cohort of differentially expressed genes that were further prioritized using stringent filtering criteria and validated by RT-qPCR. Several key factors associated with the cytoskeleton, cell cycle or extracellular matrix (e.g., Cdk1, Cdkn1c, Camsap1, Col3a1, Map3k12, Sipa1l1) were mis-expressed in Mafg -/-:Mafk -/- lenses. Further, the congenital cataract-linked extracellular matrix peroxidase Pxdn was significantly overexpressed in Mafg -/-:Mafk -/- lenses, which may cause abnormal cell morphology. These data also identified the ephrin signaling receptor Epha5 to be reduced in Mafg -/-:Mafk -/- lenses. This likely contributes to the Mafg -/-:Mafk -/- multilayered lens epithelium pathology, as loss of an ephrin ligand, Efna5 (ephrin-A5), causes similar lens defects. Together, these findings uncover a novel early function of Mafg and Mafk in lens development and identify their new downstream regulatory relationships with key cellular factors.
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Affiliation(s)
- Shaili D. Patel
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Deepti Anand
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Hozumi Motohashi
- Department of Gene Expression Regulation, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Fumiki Katsuoka
- Department of Integrative Genomics, Tohoku University Tohoku Medical Megabank Organization, Sendai, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Salil A. Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, United States,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States,*Correspondence: Salil A. Lachke,
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Boas SM, Joyce KL, Cowell RM. The NRF2-Dependent Transcriptional Regulation of Antioxidant Defense Pathways: Relevance for Cell Type-Specific Vulnerability to Neurodegeneration and Therapeutic Intervention. Antioxidants (Basel) 2021; 11:antiox11010008. [PMID: 35052512 PMCID: PMC8772787 DOI: 10.3390/antiox11010008] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Accepted: 12/14/2021] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress has been implicated in the etiology and pathobiology of various neurodegenerative diseases. At baseline, the cells of the nervous system have the capability to regulate the genes for antioxidant defenses by engaging nuclear factor erythroid 2 (NFE2/NRF)-dependent transcriptional mechanisms, and a number of strategies have been proposed to activate these pathways to promote neuroprotection. Here, we briefly review the biology of the transcription factors of the NFE2/NRF family in the brain and provide evidence for the differential cellular localization of NFE2/NRF family members in the cells of the nervous system. We then discuss these findings in the context of the oxidative stress observed in two neurodegenerative diseases, Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), and present current strategies for activating NFE2/NRF-dependent transcription. Based on the expression of the NFE2/NRF family members in restricted populations of neurons and glia, we propose that, when designing strategies to engage these pathways for neuroprotection, the relative contributions of neuronal and non-neuronal cell types to the overall oxidative state of tissue should be considered, as well as the cell types which have the greatest intrinsic capacity for producing antioxidant enzymes.
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Affiliation(s)
- Stephanie M. Boas
- Department of Neuroscience, Southern Research, 2000 9th Avenue South, Birmingham, AL 35205, USA; (S.M.B.); (K.L.J.)
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294, USA
| | - Kathlene L. Joyce
- Department of Neuroscience, Southern Research, 2000 9th Avenue South, Birmingham, AL 35205, USA; (S.M.B.); (K.L.J.)
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294, USA
| | - Rita M. Cowell
- Department of Neuroscience, Southern Research, 2000 9th Avenue South, Birmingham, AL 35205, USA; (S.M.B.); (K.L.J.)
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294, USA
- Correspondence:
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Hayashi T, Shibata T, Nakamura M, Sakurai N, Takano H, Ota M, Nomura-Horita T, Hayashi R, Shimasaki T, Ostuka T, Tahara T, Arisawa T. MAFK Polymorphisms Located in 3'-UTR are Associated with Severity of Atrophy and CDKN2A Methylation Status in the Gastric Mucosa. Genet Test Mol Biomarkers 2021; 25:255-262. [PMID: 33877894 DOI: 10.1089/gtmb.2020.0299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Objective: This study aimed to clarify the association of MAFK polymorphisms (rs4268033, rs3735656, and rs10226620) with the degree of gastric mucosal atrophy and CDKN2A CpG methylation status. Methods: A total of 491 subjects were enrolled in this study. Genotypes and methylation status were determined by polymerase chain reaction (PCR)-single-stranded conformation polymorphism and methylation-specific PCR (Fujita Health University, HM18-094). Methods: A total of 491 subjects were enrolled in this study. Genotypes and methylation status were determined by polymerase chain reaction (PCR)-single-stranded conformation polymorphism and methylation-specific PCR (Fujita Health University, HM18-094). Results: Either rs3735656 or rs10226620, located in the 3'-UTR of MAFK, was significantly associated with the severity of gastric mucosal atrophy using a dominant genetic model (odds ratio [OR], 2.10; p = 0.0012, and OR, 1.98; p = 0.0027, respectively). However, using a recessive genetic model, no significant association was found between three polymorphisms and gastric mucosal atrophy. The serum pepsinogen I/II ratio was significantly lower in subjects with minor alleles of rs3735656 and rs10226620 than in subjects with the wild homozygous allele (p = 0.018 and 0.013, respectively). In a subgroup including 400 of the 491 subjects, the CpG of p14ARF and p16 INK4a were methylated in 132 and 112 subjects, respectively. Fifty subjects had both CpG methylations and 206 subjects had neither methylation. When comparing the groups with both and neither methylations, there were no significant associations between three polymorphisms and CDKN2A methylation using a dominant genetic model. However, all polymorphisms investigated in this study (rs4268033, rs3735656, and rs10226620) were significantly associated with CDKN2A methylation in a recessive genetic model (OR, 3.58; p = 0.0071, OR, 4.49; p = 0.0004, and OR, 3.45; p = 0.0027, respectively). Conclusions: Our results indicate that carrying the minor allele of the MAFK polymorphisms, particularly when they are located in the 3'-UTR, has a high risk for the severity of gastric mucosal atrophy; furthermore, CDKN2A CpG methylation may develop in subjects with homozygous minor allele of these polymorphisms.
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Affiliation(s)
- Tasuku Hayashi
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Tomoyuki Shibata
- Department of Gastroenterology, Fujita Health University, Kutsukake-cho, Japan
| | - Masakatsu Nakamura
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Naoko Sakurai
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Hikaru Takano
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Masafumi Ota
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Tomoe Nomura-Horita
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Ranji Hayashi
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Takeo Shimasaki
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Toshimi Ostuka
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
| | - Tomomitsu Tahara
- Department of Gastroenterology and Hepatology, Kansai Medical University, Hirakata, Japan
| | - Tomiyasu Arisawa
- Department of Gastroenterology, Kanazawa Medical University, Uchinada-machi, Japan
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Direct and Specific Functional Evaluation of the Nrf2 and MafG Heterodimer by Introducing a Tethered Dimer into Small Maf-Deficient Cells. Mol Cell Biol 2019; 39:MCB.00273-19. [PMID: 31383749 DOI: 10.1128/mcb.00273-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 07/23/2019] [Indexed: 02/07/2023] Open
Abstract
A group of cytoprotective genes is regulated by heterodimers composed of the cap'n'collar (CNC) family member Nrf2 and one of the small Maf (sMaf) proteins (MafF, MafG, or MafK) through the antioxidant response element (ARE, also referred to as the CNC-sMaf binding element [CsMBE]). Many lines of evidence support this model; however, a direct and specific evaluation of the Nrf2-sMaf heterodimer remains to be executed. To address this issue, we constructed a tethered Nrf2-MafG (T-N2G) heterodimer using a flexible linker peptide. We then introduced the T-N2G construct into cells lacking all three sMaf proteins to specifically evaluate the function of the tethered heterodimer without interference from other endogenous CNC-sMaf heterodimers or sMaf homodimers. In response to an Nrf2 activator, diethyl maleate, the T-N2G protein can widely activate the target genes of Nrf2 but not those of Nrf1, such as proteasome subunit genes. Genome-wide binding analysis showed that the T-N2G protein preferentially bound to the CsMBE motifs in the regulatory regions of the Nrf2 target genes. These results provide direct evidence that the Nrf2-MafG heterodimer acts as a transcriptional activator of Nrf2-dependent genes and show that this assay system will be a powerful tool to specifically examine the function of other CNC-sMaf heterodimers.
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Wang S, Chen J, Garcia SP, Liang X, Zhang F, Yan P, Yu H, Wei W, Li Z, Wang J, Le H, Han Z, Luo X, Day DS, Stevens SM, Zhang Y, Park PJ, Liu ZJ, Sun K, Yuan GC, Pu WT, Zhang B. A dynamic and integrated epigenetic program at distal regions orchestrates transcriptional responses to VEGFA. Genome Res 2019; 29:193-207. [PMID: 30670628 PMCID: PMC6360815 DOI: 10.1101/gr.239053.118] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 12/12/2018] [Indexed: 01/29/2023]
Abstract
Cell behaviors are dictated by epigenetic and transcriptional programs. Little is known about how extracellular stimuli modulate these programs to reshape gene expression and control cell behavioral responses. Here, we interrogated the epigenetic and transcriptional response of endothelial cells to VEGFA treatment and found rapid chromatin changes that mediate broad transcriptomic alterations. VEGFA-responsive genes were associated with active promoters, but changes in promoter histone marks were not tightly linked to gene expression changes. VEGFA altered transcription factor occupancy and the distal epigenetic landscape, which profoundly contributed to VEGFA-dependent changes in gene expression. Integration of gene expression, dynamic enhancer, and transcription factor occupancy changes induced by VEGFA yielded a VEGFA-regulated transcriptional regulatory network, which revealed that the small MAF transcription factors are master regulators of the VEGFA transcriptional program and angiogenesis. Collectively these results revealed that extracellular stimuli rapidly reconfigure the chromatin landscape to coordinately regulate biological responses.
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Affiliation(s)
- Shiyan Wang
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jiahuan Chen
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Sara P Garcia
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02215, USA
| | - Xiaodong Liang
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fang Zhang
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pengyi Yan
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Huijing Yu
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Weiting Wei
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zixuan Li
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingfang Wang
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Huangying Le
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zeguang Han
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xusheng Luo
- School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Daniel S Day
- Department for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Sean M Stevens
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Yan Zhang
- Renji-Med Clinical Stem Cell Research Center, Renji Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Peter J Park
- Department for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Zhi-Jie Liu
- Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Kun Sun
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Guo-Cheng Yuan
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02215, USA
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts 02138, USA
| | - Bing Zhang
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai 200240, China
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Abstract
SIGNIFICANCE Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that coordinates the basal and stress-inducible activation of a vast array of cytoprotective genes. Understanding the regulation of Nrf2 activity and downstream pathways has major implications for human health. Recent Advances: Nrf2 regulates the transcription of components of the glutathione and thioredoxin antioxidant systems, as well as enzymes involved in phase I and phase II detoxification of exogenous and endogenous products, NADPH regeneration, and heme metabolism. It therefore represents a crucial regulator of the cellular defense mechanisms against xenobiotic and oxidative stress. In addition to antioxidant responses, Nrf2 is involved in other cellular processes, such as autophagy, intermediary metabolism, stem cell quiescence, and unfolded protein response. Given the wide range of processes that Nrf2 controls, its activity is tightly regulated at multiple levels. Here, we review the different modes of regulation of Nrf2 activity and the current knowledge of Nrf2-mediated transcriptional control. CRITICAL ISSUES It is now clear that Nrf2 lies at the center of a complex regulatory network. A full comprehension of the Nrf2 program will require an integrated consideration of all the different factors determining Nrf2 activity. FUTURE DIRECTIONS Additional computational and experimental studies are needed to obtain a more dynamic global view of Nrf2-mediated gene regulation. In particular, studies comparing how the Nrf2-dependent network changes from a physiological to a pathological condition can provide insight into mechanisms of disease and instruct new treatment strategies.
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Affiliation(s)
- Claudia Tonelli
- 1 Cold Spring Harbor Laboratory , Cold Spring Harbor, New York
| | | | - David A Tuveson
- 1 Cold Spring Harbor Laboratory , Cold Spring Harbor, New York.,2 Lustgarten Foundation Pancreatic Cancer Research Laboratory , Cold Spring Harbor, New York
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Yamamoto M, Kensler TW, Motohashi H. The KEAP1-NRF2 System: a Thiol-Based Sensor-Effector Apparatus for Maintaining Redox Homeostasis. Physiol Rev 2018; 98:1169-1203. [PMID: 29717933 PMCID: PMC9762786 DOI: 10.1152/physrev.00023.2017] [Citation(s) in RCA: 1258] [Impact Index Per Article: 179.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Kelch-like ECH-associated protein 1-NF-E2-related factor 2 (KEAP1-NRF2) system forms the major node of cellular and organismal defense against oxidative and electrophilic stresses of both exogenous and endogenous origins. KEAP1 acts as a cysteine thiol-rich sensor of redox insults, whereas NRF2 is a transcription factor that robustly transduces chemical signals to regulate a battery of cytoprotective genes. KEAP1 represses NRF2 activity under quiescent conditions, whereas NRF2 is liberated from KEAP1-mediated repression on exposure to stresses. The rapid inducibility of a response based on a derepression mechanism is an important feature of the KEAP1-NRF2 system. Recent studies have unveiled the complexities of the functional contributions of the KEAP1-NRF2 system and defined its broader involvement in biological processes, including cell proliferation and differentiation, as well as cytoprotection. In this review, we describe historical milestones in the initial characterization of the KEAP1-NRF2 system and provide a comprehensive overview of the molecular mechanisms governing the functions of KEAP1 and NRF2, as well as their roles in physiology and pathology. We also refer to the clinical significance of the KEAP1-NRF2 system as an important prophylactic and therapeutic target for various diseases, particularly aging-related disorders. We believe that controlled harnessing of the KEAP1-NRF2 system is a key to healthy aging and well-being in humans.
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Fish AE, Crawford DC, Capra JA, Bush WS. Local ancestry transitions modify snp-trait associations. PACIFIC SYMPOSIUM ON BIOCOMPUTING. PACIFIC SYMPOSIUM ON BIOCOMPUTING 2018; 23:424-435. [PMID: 29218902 PMCID: PMC5728664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Genomic maps of local ancestry identify ancestry transitions - points on a chromosome where recent recombination events in admixed individuals have joined two different ancestral haplotypes. These events bring together alleles that evolved within separate continential populations, providing a unique opportunity to evaluate the joint effect of these alleles on health outcomes. In this work, we evaluate the impact of genetic variants in the context of nearby local ancestry transitions within a sample of nearly 10,000 adults of African ancestry with traits derived from electronic health records. Genetic data was located using the Metabochip, and used to derive local ancestry. We develop a model that captures the effect of both single variants and local ancestry, and use it to identify examples where local ancestry transitions significantly interact with nearby variants to influence metabolic traits. In our most compelling example, we find that the minor allele of rs16890640 occuring on a European background with a downstream local ancestry transition to African ancestry results in significantly lower mean corpuscular hemoglobin and volume. This finding represents a new way of discovering genetic interactions, and is supported by molecular data that suggest changes to local ancestry may impact local chromatin looping.
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Affiliation(s)
- Alexandra E Fish
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37235, USA, ²Departments of Biological Sciences, Biomedical Informatics, and Computer Science, Vanderbilt University, Nashville, TN 37235, USA,
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11
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Arisawa T, Nakamura M, Otsuka T, Jing W, Sakurai N, Takano H, Hayashi T, Ota M, Nomura T, Hayashi R, Shimasaki T, Tahara T, Shibata T. Genetic polymorphisms of MAFK, encoding a small Maf protein, are associated with susceptibility to ulcerative colitis in Japan. World J Gastroenterol 2017; 23:5364-5370. [PMID: 28839436 PMCID: PMC5550785 DOI: 10.3748/wjg.v23.i29.5364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/14/2017] [Accepted: 07/04/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate whether single nucleotide polymorphisms in maf protein K (MAFK), which encodes the MAFK, lead to increased susceptibility to ulcerative colitis in the Japanese population.
METHODS This case control study examined the associations between MAFK single nucleotide polymorphisms (rs4268033 G>A, rs3735656 T>C and rs10226620 C>T) and ulcerative colitis susceptibility in 174 patients with ulcerative colitis (UC) cases, and 748 subjects without no lower abdominal symptoms, diarrhea or hematochezia (controls). In addition, as the second controls, we set 360 subjects, who have an irregular bowel movement without abnormal lower endoscopic findings (IBM controls).
RESULTS The genotype frequency of rs4268033 AA and allelic frequency of the rs4268033A allele were significantly higher in the UC cases than in both controls (P = 0.0005 and < 0.0001, P = 0.015 and 0.0027 vs controls and IBM controls, respectively). Logistic regression analysis after adjustment for age and gender showed that the rs4268033 AA and rs3735656 CC genotypes were significantly associated with susceptibility to UC development (OR = 2.63, 95%CI: 1.61-4.30, P = 0.0001 and OR = 1.81; 95%CI: 1.12-2.94, P = 0.015, respectively). Similar findings were observed by the comparison with IBM controls. In addition, the rs4268033 AA genotype was significantly associated with all phenotypes of UC except early onset. There was no significant association between rs10226620 and ulcerative colitis.
CONCLUSION Our results provide the first evidence that MAFK genetic polymorphisms are significantly associated with susceptibility to UC development. In particular, rs4268033 is closely associated with an increased risk for the development of UC.
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12
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Katsuoka F, Yamazaki H, Yamamoto M. Small Maf deficiency recapitulates the liver phenotypes of Nrf1- and Nrf2-deficient mice. Genes Cells 2016; 21:1309-1319. [PMID: 27723178 DOI: 10.1111/gtc.12445] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/15/2016] [Indexed: 12/29/2022]
Abstract
Nrf1 and Nrf2 (NF-E2-related factors 1 and 2, respectively) are transcription factors that belong to the Cap'n'collar (CNC) family and play critical roles in various tissues, including the liver. Liver-specific Nrf1 knockout mice show hepatic steatosis, accompanied by dysregulation of various metabolic genes. Nrf2 knockout mice show impairment in the induction of antioxidant and xenobiotic-metabolizing enzyme genes. Although it has been shown that small Maf (sMaf) proteins act as obligatory partners of CNC proteins, their precise contributions to the function of CNC proteins remain unclear especially in the context of adult liver functions. To address this issue, we generated mice that conditionally lack expression of all sMaf proteins in the liver. The liver-specific sMaf-deficient mice develop hepatic steatosis and dysregulation of genes involved in lipid and amino acid metabolism and proteasomal subunit expression. Importantly, the gene expression profiles in the sMaf-deficient livers share a strong similarity with those in Nrf1-deficient livers. In addition, the basal expression levels of a number of Nrf2 target genes were diminished in the sMaf-deficient livers. These results provide the first genetic evidence that sMaf proteins are indispensable for liver functions as heterodimeric partners for Nrf1 and Nrf2.
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Affiliation(s)
- Fumiki Katsuoka
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, 980-8573, Japan
| | - Hiromi Yamazaki
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Masayuki Yamamoto
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, 980-8573, Japan.,Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
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13
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Zang C, Luyten A, Chen J, Liu XS, Shivdasani RA. NF-E2, FLI1 and RUNX1 collaborate at areas of dynamic chromatin to activate transcription in mature mouse megakaryocytes. Sci Rep 2016; 6:30255. [PMID: 27457419 PMCID: PMC4960521 DOI: 10.1038/srep30255] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/01/2016] [Indexed: 12/16/2022] Open
Abstract
Mutations in mouse and human Nfe2, Fli1 and Runx1 cause thrombocytopenia. We applied genome-wide chromatin dynamics and ChIP-seq to determine these transcription factors’ (TFs) activities in terminal megakaryocyte (MK) maturation. Enhancers with H3K4me2-marked nucleosome pairs were most enriched for NF-E2, FLI and RUNX sequence motifs, suggesting that this TF triad controls much of the late MK program. ChIP-seq revealed NF-E2 occupancy near previously implicated target genes, whose expression is compromised in Nfe2-null cells, and many other genes that become active late in MK differentiation. FLI and RUNX were also the motifs most enriched near NF-E2 binding sites and ChIP-seq implicated FLI1 and RUNX1 in activation of late MK, including NF-E2-dependent, genes. Histones showed limited activation in regions of single TF binding, while enhancers that bind NF-E2 and either RUNX1, FLI1 or both TFs gave the highest signals for TF occupancy and H3K4me2; these enhancers associated best with genes activated late in MK maturation. Thus, three essential TFs co-occupy late-acting cis-elements and show evidence for additive activity at genes responsible for platelet assembly and release. These findings provide a rich dataset of TF and chromatin dynamics in primary MK and explain why individual TF losses cause thrombopocytopenia.
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Affiliation(s)
- Chongzhi Zang
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard T.H. Chan School of Public Health, Boston, MA 02215, USA.,Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Annouck Luyten
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Justina Chen
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - X Shirley Liu
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard T.H. Chan School of Public Health, Boston, MA 02215, USA.,Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Ramesh A Shivdasani
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.,Department of Pediatric Hematology/Oncology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
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14
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Small Maf proteins (MafF, MafG, MafK): History, structure and function. Gene 2016; 586:197-205. [PMID: 27058431 DOI: 10.1016/j.gene.2016.03.058] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/11/2016] [Accepted: 03/30/2016] [Indexed: 12/12/2022]
Abstract
The small Maf proteins (sMafs) are basic region leucine zipper (bZIP)-type transcription factors. The basic region of the Maf family is unique among the bZIP factors, and it contributes to the distinct DNA-binding mode of this class of proteins. MafF, MafG and MafK are the three vertebrate sMafs, and no functional differences have been observed among them in terms of their bZIP structures. sMafs form homodimers by themselves, and they form heterodimers with cap 'n' collar (CNC) proteins (p45 NF-E2, Nrf1, Nrf2, and Nrf3) and also with Bach proteins (Bach1 and Bach2). Because CNC and Bach proteins cannot bind to DNA as monomers, sMafs are indispensable partners that are required by CNC and Bach proteins to exert their functions. sMafs lack the transcriptional activation domain; hence, their homodimers act as transcriptional repressors. In contrast, sMafs participate in transcriptional activation or repression depending on their heterodimeric partner molecules and context. Mouse genetic analyses have revealed that various biological pathways are under the regulation of CNC-sMaf heterodimers. In this review, we summarize the history and current progress of sMaf studies in relation to their partners.
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15
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Furusawa A, Sadashivaiah K, Singh ZN, Civin CI, Banerjee A. Inefficient megakaryopoiesis in mouse hematopoietic stem-progenitor cells lacking T-bet. Exp Hematol 2016; 44:194-206.e17. [PMID: 26607595 PMCID: PMC4789076 DOI: 10.1016/j.exphem.2015.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 10/15/2015] [Accepted: 11/05/2015] [Indexed: 12/22/2022]
Abstract
Differentiation of hematopoietic stem-progenitor cells (HSPCs) into mature blood lineages results from the translation of extracellular signals into changes in the expression levels of transcription factors controlling cell fate decisions. Multiple transcription factor families are known to be involved in hematopoiesis. Although the T-box transcription factor family is known to be involved in the differentiation of multiple tissues, and expression of T-bet, a T-box family transcription factor, has been observed in HSPCs, T-box family transcription factors do not have a described role in HSPC differentiation. In the current study, we address the functional consequences of T-bet expression in mouse HSPCs. T-bet protein levels differed among HSPC subsets, with highest levels observed in megakaryo-erythroid progenitor cells (MEPs), the common precursor to megakaryocytes and erythrocytes. HSPCs from T-bet-deficient mice exhibited a defect in megakaryocytic differentiation when cultured in the presence of thrombopoietin. In contrast, erythroid differentiation in culture in the presence of erythropoietin was not substantially altered in T-bet-deficient HSPCs. Differences observed with respect to megakaryocyte number and maturity, as assessed by level of expression of CD41 and CD61, and megakaryocyte ploidy, in T-bet-deficient HSPCs were not associated with altered proliferation or survival in culture. Gene expression micro-array analysis of MEPs from T-bet-deficient mice exhibited diminished expression of multiple genes associated with the megakaryocyte lineage. These data advance our understanding of the transcriptional regulation of megakaryopoiesis by supporting a new role for T-bet in the differentiation of MEPs into megakaryocytes.
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Affiliation(s)
- Aki Furusawa
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD; Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD; Center for Stem Cell Research and Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD
| | - Kavitha Sadashivaiah
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD; Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD; Center for Stem Cell Research and Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD
| | - Zeba N Singh
- Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD; Department of Pathology, University of Maryland School of Medicine, Baltimore, MD
| | - Curt I Civin
- Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD; Center for Stem Cell Research and Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD; Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD
| | - Arnob Banerjee
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD; Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD; Center for Stem Cell Research and Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD.
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16
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Compound mouse mutants of bZIP transcription factors Mafg and Mafk reveal a regulatory network of non-crystallin genes associated with cataract. Hum Genet 2015; 134:717-35. [PMID: 25896808 DOI: 10.1007/s00439-015-1554-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/08/2015] [Indexed: 12/11/2022]
Abstract
Although majority of the genes linked to early-onset cataract exhibit lens fiber cell-enriched expression, our understanding of gene regulation in these cells is limited to function of just eight transcription factors and largely in the context of crystallins. We report on small Maf transcription factors Mafg and Mafk as regulators of several non-crystallin human cataract-associated genes in fiber cells and establish their significance to this disease. We applied a bioinformatics tool for cataract gene discovery iSyTE to identify Mafg and its co-regulators in the lens, and generated various null-allelic combinations of Mafg:Mafk mouse mutants for phenotypic and molecular analysis. By age 4 months, Mafg-/-:Mafk+/- mutants exhibit lens defects that progressively develop into cataract. High-resolution phenotypic characterization of Mafg-/-:Mafk+/- mouse lens reveals severely disorganized fiber cells, while microarray-based expression profiling identifies 97 differentially regulated genes (DRGs). Integrative analysis of Mafg-/-:Mafk+/- lens-DRGs with (1) binding motifs and genomic targets of small Mafs and their regulatory partners, (2) iSyTE lens expression data, and (3) interactions between DRGs in the String database, unravel a detailed small Maf regulatory network in the lens, several nodes of which are linked to cataract. This approach identifies 36 high-priority candidates from the original 97 DRGs. Significantly, 8/36 (22%) DRGs are associated with cataracts in human (GSTO1, MGST1, SC4MOL, UCHL1) or mouse (Aldh3a1, Crygf, Hspb1, Pcbd1), suggesting a multifactorial etiology that includes oxidative stress and misregulation of sterol synthesis. These data identify Mafg and Mafk as new cataract-associated candidates and define their function in regulating largely non-crystallin genes linked to human cataract.
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17
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Hirano K, Kinoshita T, Uemura T, Motohashi H, Watanabe Y, Ebihara T, Nishiyama H, Sato M, Suga M, Maruyama Y, Tsuji NM, Yamamoto M, Nishihara S, Sato C. Electron microscopy of primary cell cultures in solution and correlative optical microscopy using ASEM. Ultramicroscopy 2014; 143:52-66. [DOI: 10.1016/j.ultramic.2013.10.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
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18
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Martínez-Hernández A, Gutierrez-Malacatt H, Carrillo-Sánchez K, Saldaña-Alvarez Y, Rojas-Ochoa A, Crespo-Solis E, Aguayo-González A, Rosas-López A, Ayala-Sanchez JM, Aquino-Ortega X, Orozco L, Cordova EJ. Small MAF genes variants and chronic myeloid leukemia. Eur J Haematol 2013; 92:35-41. [PMID: 24118457 DOI: 10.1111/ejh.12211] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2013] [Indexed: 12/18/2022]
Abstract
Chronic myeloid leukemia (CML) is one of the most frequent hematological neoplasia worldwide. The abnormal accumulation of reactive oxygen species may be an important factor in CML development. The transcription factor NRF2 can regulate the transcription of a battery of antioxidant and detoxificant genes after heterodimerizing with small-Maf proteins. Although the participation of NRF2 in the development of chronic degenerative diseases has been thoroughly studied, the role of small-Maf genes has not been documented. We have identified polymorphisms in the three MAF genes (F, G and K) and assessed their association with CML. Over 266 subjects with CML and 399 unrelated healthy donors have been studied. After sequencing each MAF gene by Sanger technology, we found 17 variants in MAFF gene, eight in MAFG and seven in MAFK. In the case-control study, the homozygote genotype CC for the rs9610915 SNP of MAFF was significantly associated with CML. The frequency of the ACC haplotype from MAFK was significantly lower than controls. After stratification by gender, the ACC and GTG haplotypes were associated only with males with CML. These novel data suggest an association between MAFF and MAFG and the development of CML.
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Affiliation(s)
- Angelica Martínez-Hernández
- Immunogenomics and Metabolic Diseases Laboratory, Instituto Nacional de Medicina Genómica, SS, México City, México
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19
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Abstract
NF-E2 is a heterodimeric transcription factor consisting of p45 and small Maf subunits. Since p45(-/-) mice display severe thrombocytopenia, p45 is recognized as a critical regulator of platelet production from megakaryocytes. To identify direct p45 target genes in megakaryocytes, we used chromatin immunoprecipitation (ChIP) sequencing to analyze the genome-wide chromatin occupancy of p45 in primary megakaryocytes. p45 target gene candidates obtained from the analysis are implicated in the production and function of platelets. Two of these genes, Selp and Myl9, were verified as direct p45 targets through multiple approaches. Since P-selectin, encoded by Selp, plays a critical role in platelet function during thrombogenesis, we tested whether p45 determines the intrinsic reactivity and potency of platelets generated from megakaryocytes. Mice expressing a hypomorphic p45 mutant instead of wild-type p45 in megakaryocytes (p45(-/-):ΔNTD-Tg mice) displayed platelet hypofunction accompanied by mild thrombocytopenia. Furthermore, lung metastasis of melanoma cells, which requires platelet activation, was repressed in p45(-/-):ΔNTD-Tg mice compared to control mice, validating the impaired function of platelets produced from p45(-/-):ΔNTD-Tg megakaryocytes. By activating genes in megakaryocytes that mediate platelet production and function, p45 determines the quantity and quality of platelets.
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20
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Takayama N, Eto K. Pluripotent stem cells reveal the developmental biology of human megakaryocytes and provide a source of platelets for clinical application. Cell Mol Life Sci 2012; 69:3419-28. [PMID: 22527724 PMCID: PMC3445798 DOI: 10.1007/s00018-012-0995-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/22/2012] [Accepted: 04/05/2012] [Indexed: 12/12/2022]
Abstract
Human pluripotent stem cells [PSCs; including human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs)] can infinitely proliferate in vitro and are easily accessible for gene manipulation. Megakaryocytes (MKs) and platelets can be created from human ESCs and iPSCs in vitro and represent a potential source of blood cells for transfusion and a promising tool for studying the human thrombopoiesis. Moreover, disease-specific iPSCs are a powerful tool for elucidating the pathogenesis of hematological diseases and for drug screening. In that context, we and other groups have developed in vitro MK and platelet differentiation systems from human pluripotent stem cells (PSCs). Combining this co-culture system with a drug-inducible gene expression system enabled us to clarify the novel role played by c-MYC during human thrombopoiesis. In the next decade, technical advances (e.g., high-throughput genomic sequencing) will likely enable the identification of numerous gene mutations associated with abnormal thrombopoiesis. Combined with such technology, an in vitro system for differentiating human PSCs into MKs and platelets could provide a novel platform for studying human gene function associated with thrombopoiesis.
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Affiliation(s)
- Naoya Takayama
- Clinical Application Department, Center for iPS Cell Research and Application, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
| | - Koji Eto
- Clinical Application Department, Center for iPS Cell Research and Application, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
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21
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Regulation of APC development, immune response, and autoimmunity by Bach1/HO-1 pathway in mice. Blood 2012; 120:2428-37. [PMID: 22791292 DOI: 10.1182/blood-2012-04-426247] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
APCs are essential for innate and adaptive immunity as well as self-immune tolerance. Here, we show that the Cap'n'collar member Bach1 regulates the generation of APCs, specifically macrophages and dendritic cells, in mice. The impaired APC development in Bach1(-/-) mice was accompanied by defects in downstream T-cell responses and partial protection from experimental autoimmune encephalomyelitis. Genomewide analyses identified a panel of Bach1 target genes and ablation of the direct Bach1 target gene HO-1 exacerbated the impaired APC development observed in Bach1(-/-) mice. This was attributed to the impaired ability of HO-1(-/-)Bach1(-/-) double mutants to produce upstream APC progenitor cells, including common myeloid progenitor (CMP)-Flk2(+). By contrast, we observed an increase in hematopoietic stem-progenitor cells (HSPCs) in these mice, suggesting a developmental block in the progression of HSPCs to CMP-Flk2(+) and subsequently APCs.
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22
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Embryonic lethality and fetal liver apoptosis in mice lacking all three small Maf proteins. Mol Cell Biol 2011; 32:808-16. [PMID: 22158967 DOI: 10.1128/mcb.06543-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Embryogenesis is a period during which cells are exposed to dynamic changes of various intracellular and extracellular stresses. Oxidative stress response genes are regulated by heterodimers composed of Cap'n'Collar (CNC) and small Maf proteins (small Mafs) that bind to antioxidant response elements (ARE). Whereas CNC factors have been shown to contribute to the expression of ARE-dependent cytoprotective genes during embryogenesis, the specific contribution of small Maf proteins to such gene regulation remains to be fully examined. To delineate the small Maf function in vivo, in this study we examined mice lacking all three small Mafs (MafF, MafG, and MafK). The small Maf triple-knockout mice developed normally until embryonic day 9.5 (E9.5). Thereafter, however, the triple-knockout embryos showed severe growth retardation and liver hypoplasia, and the embryos died around E13.5. ARE-dependent cytoprotective genes were expressed normally in E10.5 triple-knockout embryos, but the expression was significantly reduced in the livers of E13.5 mutant embryos. Importantly, the embryonic lethality could be completely rescued by transgenic expression of exogenous MafG under MafG gene regulatory control. These results thus demonstrate that small Maf proteins are indispensable for embryonic development after E9.5, especially for liver development, but early embryonic development does not require small Mafs.
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Kobayashi A, Tsukide T, Miyasaka T, Morita T, Mizoroki T, Saito Y, Ihara Y, Takashima A, Noguchi N, Fukamizu A, Hirotsu Y, Ohtsuji M, Katsuoka F, Yamamoto M. Central nervous system-specific deletion of transcription factor Nrf1 causes progressive motor neuronal dysfunction. Genes Cells 2011; 16:692-703. [PMID: 21554501 DOI: 10.1111/j.1365-2443.2011.01522.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cap'n'Collar (CNC) proteins heterodimerize with small Maf proteins and regulate the transcription of various genes. Small Maf-deficient mice develop severe neurodegeneration, and it remains unclear whether CNC proteins are involved in this process. In this study, we examined the contribution of Nrf1, one of the CNC proteins, to neuronal homeostasis in vivo. As Nrf1 gene knockout mice are embryonic lethal, we developed a central nervous system (CNS)-specific Nrf1 knockout (CKO) mouse line using mice bearing an Nrf1(flox) allele and Nestin-Cre allele. At birth, the CKO mice appeared indistinguishable from control mice, but thereafter they showed progressive motor ataxia and severe weight loss. All Nrf1 CKO mice died within 3 weeks. These phenotypes are similar to those reported in small Maf-deficient mice, suggesting the presence of collaboration between Nrf1 and small Maf proteins. We also found aberrant accumulation of polyubiquitinated proteins in various CNS regions and apparent neuronal loss in the hippocampus of Nrf1 CKO mice. An oxidative stress marker was accumulated in the spinal cords of the mice, but the expression patterns of oxidative stress response genes regulated by Nrf2 did not change substantially. These results show that Nrf1 sustains the CNS homeostasis through regulating target genes distinct from those regulated by Nrf2.
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Affiliation(s)
- Akira Kobayashi
- Department of Genetic Cord, Graduate School of Life and Medical Sciences, Doshisha University, 1-3 Miyakodani, Tatara, Kyotanabe 610-0394, Japan.
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24
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Abstract
MafG and p45 possess basic region-leucine zipper (bZip) domains and form a heterodimer called NF-E2, a key regulator of megakaryopoiesis. NF-E2 binds to the Maf recognition element (MARE) and activates transcription of many platelet genes. Since the bZip domain, which mediates DNA binding and heterodimerization, is the only functional domain established for MafG, it has been assumed that MafG is required only for p45 binding to MARE and to facilitate p45-mediated transcriptional activation. Analysis of the C-terminal region of MafG, which is distinct from the bZip domain, revealed that this region contains a nuclear matrix-targeting signal. We used a transgenic complementation rescue assay to delineate the function of the MafG C terminus in vivo. Transgenic mice expressing a mutant MafG protein lacking the C terminus (MafGΔC) were crossed into a MafG-null background. The compound mutant mice displayed severe thrombocytopenia and splenomegaly, which phenocopied p45-null mice. The MafG C terminus is essential for proplatelet formation and platelet gene activation but not for p45 binding to MARE. These results demonstrate that the MafG C terminus is required for NF-E2 function and suggest that efficient targeting of NF-E2 to a specific nuclear scaffold is important to achieve high-level activity.
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Genetic analysis of hierarchical regulation for Gata1 and NF-E2 p45 gene expression in megakaryopoiesis. Mol Cell Biol 2010; 30:2668-80. [PMID: 20351175 DOI: 10.1128/mcb.01304-09] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
GATA1 and NF-E2 p45 are two important regulators of megakaryopoiesis. Whereas GATA1 is known to regulate the p45 gene, details of the GATA1 contribution to the spatiotemporal expression of the p45 gene remain to be elucidated. To clarify the relationship between GATA1 and p45, we performed genetic complementation rescue analysis of p45 function in megakaryocytes utilizing the hematopoietic regulatory domain of the Gata1 gene (G1HRD). We established transgenic mouse lines expressing p45 under G1HRD regulation and crossed the mice with p45-null mice. Compound mutant mice displayed normal platelet counts and no sign of hemorrhage, indicating that G1HRD has the ability to express p45 in a spatiotemporally correct manner. However, deletion of 38 amino acids from the N-terminal region of p45 abrogated the p45 rescue function, suggesting the presence of an essential transactivation activity in the region. We then crossed the G1HRD-p45 transgenic mice with megakaryocyte-specific Gata1 gene knockdown (Gata1(Delta)(neo)(Delta)(HS)) mice. The G1HRD-p45 transgene was insufficient for complete rescue of the Gata1(Delta)(neo)(Delta)(HS) megakaryocytes, suggesting that GATA1 or other factors regulated by GATA1 are required to cooperate with p45 for normal megakaryopoiesis. This study thus provides a unique in vivo validation of the hierarchical relationship between GATA1 and p45 in megakaryocytes.
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Abstract
In megakaryocytes, the maturation process and oxidative stress response appear to be closely related. It has been suggested that increased oxygen tension and reactive oxygen species (ROS) promote megakaryopoiesis and that the expression of stress-responsive genes responsible for ROS elimination declines during megakaryocytic maturation. NF-E2 p45 is an essential regulator of megakaryopoiesis, whereas Nrf2 is a key activator of stress-responsive genes. Because p45 and Nrf2 have similar DNA-binding specificities, we hypothesized that p45 competes with Nrf2 to repress stress-responsive genes and achieves favorable intracellular conditions to allow ROS to be efficiently used as signaling molecules. We conducted comprehensive gene expression profiling with wild-type and p45-null megakaryocytes and examined the functional relationship between p45 and Nrf2. We found that 2 characteristic gene clusters are defined within p45 target genes: platelet genes and cytoprotective genes. The former are unique targets activated by p45, whereas the latter are common targets of p45 and Nrf2. Further analysis suggested that, as a less efficacious activator, p45 maintains moderate expression of cytoprotective genes through competing with Nrf2 and promotes ROS accumulation. Increased ROS enhanced platelet gene expression. These results suggest that p45 dominates over Nrf2 to enhance megakaryocytic maturation by promoting ROS accumulation.
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Array Comparative Genomic Hybridization for Genetic Evaluation of Fetal Loss Between 10 and 20 Weeks of Gestation. Obstet Gynecol 2009; 114:1093-1102. [DOI: 10.1097/aog.0b013e3181bc6ab0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Huang H, Yu M, Akie TE, Moran TB, Woo AJ, Tu N, Waldon Z, Lin YY, Steen H, Cantor AB. Differentiation-dependent interactions between RUNX-1 and FLI-1 during megakaryocyte development. Mol Cell Biol 2009; 29:4103-15. [PMID: 19470763 PMCID: PMC2715817 DOI: 10.1128/mcb.00090-09] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 02/21/2009] [Accepted: 05/16/2009] [Indexed: 01/13/2023] Open
Abstract
The transcription factor RUNX-1 plays a key role in megakaryocyte differentiation and is mutated in cases of myelodysplastic syndrome and leukemia. In this study, we purified RUNX-1-containing multiprotein complexes from phorbol ester-induced L8057 murine megakaryoblastic cells and identified the ets transcription factor FLI-1 as a novel in vivo-associated factor. The interaction occurs via direct protein-protein interactions and results in synergistic transcriptional activation of the c-mpl promoter. Interestingly, the interaction fails to occur in uninduced cells. Gel filtration chromatography confirms the differentiation-dependent binding and shows that it correlates with the assembly of a complex also containing the key megakaryocyte transcription factors GATA-1 and Friend of GATA-1 (FOG-1). Phosphorylation analysis of FLI-1 with uninduced versus induced L8057 cells suggests the loss of phosphorylation at serine 10 in the induced state. Substitution of Ser10 with the phosphorylation mimic aspartic acid selectively impairs RUNX-1 binding, abrogates transcriptional synergy with RUNX-1, and dominantly inhibits primary fetal liver megakaryocyte differentiation in vitro. Conversely, substitution with alanine, which blocks phosphorylation, augments differentiation of primary megakaryocytes. We propose that dephosphorylation of FLI-1 is a key event in the transcriptional regulation of megakaryocyte maturation. These findings have implications for other cell types where interactions between runx and ets family proteins occur.
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Affiliation(s)
- Hui Huang
- Children's Hospital Boston, 300 Longwood Ave., Boston, MA 02115, USA
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29
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Bluteau D, Lordier L, Di Stefano A, Chang Y, Raslova H, Debili N, Vainchenker W. Regulation of megakaryocyte maturation and platelet formation. J Thromb Haemost 2009; 7 Suppl 1:227-34. [PMID: 19630806 DOI: 10.1111/j.1538-7836.2009.03398.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Each day in every human, approximately 1 x 10(11) platelets are produced by the cytoplasmic fragmentation of megakaryocytes (MK), their marrow precursor cells. Platelets are the predominating factor in the process of hemostasis and thrombosis. Recent studies have shown that platelets also play a hitherto unsuspected role in several other processes such as inflammation, innate immunity, neoangiogenesis and tumor metastasis. The late phases of MK differentiation identified by polyploidization, maturation and organized fragmentation of the cytoplasm leading to the release of platelets in the blood stream represent a unique model of differentiation. The molecular and cellular mechanisms regulating platelet biogenesis are better understood and may explain several platelet disorders. This review focuses on MK polyploidization, and platelet formation, and discusses their alteration in some platelet disorders.
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Affiliation(s)
- D Bluteau
- INSERM, U790, 39 rue Camille Desmoulins, Villejuif, France
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30
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Antonelli A, Lenzi L, Nakagawara A, Osaki T, Chiaretti A, Aloe L. Tumor Suppressor Proteins are Differentially Affected in Human Ependymoblastoma and Medulloblastoma Cells Exposed to Nerve Growth Factor. Cancer Invest 2009; 25:94-101. [PMID: 17453820 DOI: 10.1080/07357900701205689] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The aim of our study was to investigate the role of nerve growth factor (NGF) on the expression of the p73 protein in human ependymoblastoma (EP) and medulloblastoma (MB) cells. It was found that NGF exposure on MB cells blocks proliferation, as well as on EP cells and induces overexpression of p73. NGF reduces the number of cells and promotes the expression of TrkA of these neoplastic cells. Moreover, NGF plus cisplatin treatment reduces the cytotoxic effect of cisplatin. These observations indicate that NGF by interfering with mechanisms associated with cells proliferation and survival might induce the differentiation event through TrkA pathways.
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Affiliation(s)
- A Antonelli
- Institute of Neurobiology and Molecular Medicine, CNR-EBRI, Rome, Italy
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31
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Slayton WB, Patel M, Sola-Visner M, Harris N, Rivers A, Montgomery RR, Friedman KD. Type 2B von Willebrand disease associated with the release of platelet agglutinates from megakaryocytes in the bone marrow. J Pediatr Hematol Oncol 2008; 30:708-11. [PMID: 18776767 PMCID: PMC5592795 DOI: 10.1097/mph.0b013e31817541cd] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report a child with thrombocytopenia since birth, circulating platelet agglutinates, and a tendency to bleed. A bone marrow aspirate revealed large platelet clumps within the bone marrow and megakaryocyte nuclei surrounded by halos of clumped platelets. Laboratory evaluation revealed type 2B von Willebrand disease. Gene sequencing revealed a G to C mutation at base 3923 of the VWF gene. This mutation was previously described in a family with circulating platelet clumps and abnormal megakaryopoiesis with release of clumped platelets in culture. This same mutation was previously described in a family with circulating platelet aggregates and abnormalities of platelet release from megakaryocytes in vitro. Presence of megakaryocytes with halos of clumped platelets in our patient suggests that platelet agglutinate occurs in the bone marrow in some type 2B von Willebrand disease patients.
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Interferon-alpha 2b-induced thrombocytopenia is caused by inhibition of platelet production but not proliferation and endomitosis in human megakaryocytes. Blood 2008; 112:542-50. [PMID: 18523149 DOI: 10.1182/blood-2007-12-125906] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Human interferon (IFN)-alpha is the standard therapy for chronic hepatitis C to prevent its progression to liver cirrhosis and hepatocellular carcinoma. Thrombocytopenia is one of the major adverse effects of IFN-alpha and often leads to dose reduction or treatment discontinuation. However, there is little information on how IFN-alpha inhibits human megakaryopoiesis. In this study, we demonstrated that IFN-alpha did not inhibit colony formation of megakaryocytes from human CD34(+) hematopoietic stem cells. IFN-alpha did not inhibit endomitosis but did inhibit cytoplasmic maturation of megakaryocytes and platelet production in vitro. IFN-alpha suppressed the expression of transcription factors regulating late-stage megakaryopoiesis, such as GATA-1, p45(NF-E2), MafG. IFN-alpha also significantly reduced the number of human platelets but not megakaryocytes, and did not inhibit endomitosis of human megakaryocytes in immunodeficient NOD/Shi-scid/IL-2R gamma(null) (NOG) mice transplanted with human CD34(+) cells (hu-NOG). We also demonstrated that a novel thrombopoietin mimetic, NIP-004, was effective for treating IFN-alpha-induced thrombocytopenia in hu-NOG mice. From ultrastructural study, IFN-alpha inhibited the maturation of demarcation membranes in megakaryocytes, although NIP-004 prevented the inhibitory effects of IFN-alpha. These results defined the pathogenesis of IFN-alpha-induced thrombocytopenia and suggested possible future clinical applications for thrombopoietin mimetics.
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33
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Blank V. Small Maf proteins in mammalian gene control: mere dimerization partners or dynamic transcriptional regulators? J Mol Biol 2007; 376:913-25. [PMID: 18201722 DOI: 10.1016/j.jmb.2007.11.074] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 11/09/2007] [Accepted: 11/26/2007] [Indexed: 12/13/2022]
Abstract
The small Maf basic leucine zipper (bZIP) proteins MafF, MafG and MafK, while modest in size, have emerged as crucial regulators of mammalian gene expression. Intriguingly, small Mafs do not contain an obvious transcriptional activation domain. However, previously perceived as "mere" partner molecules conferring DNA binding specificity to complexes with larger bZIP proteins, such as the CNC family member Nrf2, it has become clear that small Maf proteins are essential and dynamically regulated transcription factors. Current data suggest stringent control of small Maf protein function through transcriptional and post-translational mechanisms. Initial gene targeting experiments revealed considerable functional redundancy among small Maf proteins in vivo. This was not unexpected, due to the high level of homology among the three small Mafs. Nevertheless, further studies showed that these transcription factors have critical roles in various cellular processes, including stress signaling, hematopoiesis, CNS function and oncogenesis. Recent data provide a possible link between small Maf-mediated transcription and the inflammatory response.
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Affiliation(s)
- Volker Blank
- Lady Davis Institute for Medical Research, 3755, Côte Sainte-Catherine, Montreal, Quebec, Canada.
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34
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Fock EL, Yan F, Pan S, Chong BH. NF-E2-mediated enhancement of megakaryocytic differentiation and platelet production in vitro and in vivo. Exp Hematol 2007; 36:78-92. [PMID: 17923245 DOI: 10.1016/j.exphem.2007.08.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 08/07/2007] [Accepted: 08/09/2007] [Indexed: 12/31/2022]
Abstract
OBJECTIVE NF-E2 is a prime regulator of megakaryocyte (MK) terminal differentiation and platelet release. By overexpressing the p45 subunit of NF-E2, we aim to increase the proportion of mature MKs and the potential for platelet production in vitro and in vivo. METHODS Retroviral vectors expressing p45-NF-E2 together with the enhanced green fluorescent protein (eGFP) were used to transduce murine bone marrow cells (BMCs). Aspects of MK differentiation, proliferation, proplatelet, and platelet production were evaluated. RESULTS Compared to controls, a higher proportion of BMCs overexpressing p45-NF-E2 were found to express the MK markers CD41, CD42a, and CD42b, with some effect on cell proliferation. Early MK differentiation, characterized by colony-forming unit (CFU)-MK formation, was enhanced by p45-NF-E2 overexpression at the expense of CFU-granulocyte macrophage development. An increased number of acetylcholinesterase(+) MKs was also observed in NF-E2(++) cultures. Although endomitosis was found not to be affected, the resultant upregulation of NF-E2 target genes was also followed by significant increases in proplatelet and functional platelet production. Transplantation of enriched MK progenitor cells overexpressing p45-NF-E2 into lethally irradiated mice resulted in a threefold increase in eGFP(+)/NF-E2(++) platelet production in vivo over 10 days, although no appreciable expansion in their number was observed over 32 days. CONCLUSION These results suggest that enforced expression of p45-NF-E2 selectively enhances many aspects of MK differentiation, including MK maturation, proplatelet formation, and platelet release. In addition, p45 overexpression increases MK commitment during early megakaryopoiesis, while inhibiting white blood cell differentiation.
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Affiliation(s)
- Ee-ling Fock
- Centre for Vascular Research, Department of Medicine, St. George Clinical School, University of New South Wales, Sydney, Australia
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35
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Abstract
Megakaryocytopoiesis is the process that leads to the production of platelets. This process involves the commitment of multipotent hematopoietic stem cells toward megakaryocyte (MK) progenitors, the proliferation and differentiation of MK progenitors, the polyploidization of MK precursors and the maturation of MK. Mature MK produce platelets by cytoplasmic fragmentation occurring through a dynamic and regulated process, called proplatelet formation, and consisting of long pseudopodial elongations that break in the blood flow. Recent insights have demonstrated that the MK and erythroid lineages are tightly associated at both the cellular and molecular levels, especially in the transcription factors that regulate their differentiation programs. Megakaryocytopoiesis is regulated by two types of transcription factors, those regulating the differentiation process, such as GATA-1, and those regulating proplatelet formation, such as NF-E2. The humoral factor thrombopoietin (TPO) is the primary regulator of MK differentiation and platelet production through the stimulation of its receptor MPL. Numerous acquired or congenital pathologies of the MK lineage are now explained by molecular abnormalities in the activity of the transcription factors involved in megakaryocytopoiesis, in the Tpo or c-mpl genes, as well as in signaling molecules associated with MPL. The recent development of MPL agonists may provide efficient agents for the treatment of some thrombocytopenias.
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Affiliation(s)
- Y Chang
- INSERM, Institut Gustave Roussy, Université Paris XI, Villejuif, France
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36
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Abstract
Megakaryocytopoiesis involves the commitment of haematopoietic stem cells, and the proliferation, maturation and terminal differentiation of the megakaryocytic progenitors. Circulating levels of thrombopoietin (TPO), the primary growth-factor for the megakaryocyte (MK) lineage, induce concentration-dependent proliferation and maturation of MK progenitors by binding to the c-Mpl receptor and signalling induction. Decreased platelet turnover rates results in increased concentration of free TPO, enabling the compensatory response of marrow MKs to increased platelet production. C-Mpl activity is orchestrated by a complex cascade of signalling molecules that induces the action of specific transcription factors to drive MK proliferation and maturation. Mature MKs form proplatelet projections that are fragmented into circulating particles. Newly developed thrombopoietic agents operating via c-Mpl receptor may prove useful in supporting platelet production in thrombocytopenic state. Herein, we review the regulation of megakaryocytopoiesis and platelet production in normal and disease state, and the new approaches to thrombopoietic therapy.
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Affiliation(s)
- Varda R Deutsch
- The Haematology Institute, Tel Aviv Sourasky Medical Centre, Tel Aviv, Israel.
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37
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Aziz A, Vanhille L, Mohideen P, Kelly LM, Otto C, Bakri Y, Mossadegh N, Sarrazin S, Sieweke MH. Development of macrophages with altered actin organization in the absence of MafB. Mol Cell Biol 2006; 26:6808-18. [PMID: 16943423 PMCID: PMC1592864 DOI: 10.1128/mcb.00245-06] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In the hematopoietic system the bZip transcription factor MafB is selectively expressed at high levels in monocytes and macrophages and promotes macrophage differentiation in myeloid progenitors, whereas a dominant-negative allele can inhibit this process. To analyze the requirement of MafB for macrophage development, we generated MafB-deficient mice and, due to their neonatal lethal phenotype, analyzed macrophage differentiation in vitro, in the embryo, and in reconstituted mice. Surprisingly we observed in vitro differentiation of macrophages from E14.5 fetal liver (FL) cells and E18.5 splenocytes. Furthermore we found normal numbers of F4/80(+)/Mac-1(+) macrophages and monocytes in fetal liver, spleen, and blood as well as in bone marrow, spleen, and peritoneum of adult MafB(-/-) FL reconstituted mice. MafB(-/-) macrophages showed intact basic macrophage functions such as phagocytosis of latex beads or Listeria monocytogenes and nitric oxide production in response to lipopolysaccharide. By contrast, MafB(-/-) macrophages expressed increased levels of multiple genes involved in actin organization. Consistent with this, phalloidin staining revealed an altered morphology involving increased numbers of branched protrusions of MafB(-/-) macrophages in response to macrophage colony-stimulating factor. Together these data point to an unexpected redundancy of MafB function in macrophage differentiation and a previously unknown role in actin-dependent macrophage morphology.
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Affiliation(s)
- Athar Aziz
- Centre d'Immunologie de Marseille-Luminy, Campus de Luminy, Case 906, 13288 Marseille Cedex 09, France
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38
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Mukai HY, Motohashi H, Ohneda O, Suzuki N, Nagano M, Yamamoto M. Transgene insertion in proximity to the c-myb gene disrupts erythroid-megakaryocytic lineage bifurcation. Mol Cell Biol 2006; 26:7953-65. [PMID: 16940183 PMCID: PMC1636724 DOI: 10.1128/mcb.00718-06] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nuclear proto-oncogene c-myb plays crucial roles in the growth, survival, and differentiation of hematopoietic cells. We established three lines of erythropoietin receptor-transgenic mice and found that one of them exhibited anemia, thrombocythemia, and splenomegaly. These abnormalities were independent of the function of the transgenic erythropoietin receptor and were observed exclusively in mice harboring the transgene homozygously, suggesting transgenic disruption of a certain gene. The transgene was inserted 77 kb upstream of the c-myb gene, and c-Myb expression was markedly decreased in megakaryocyte/erythrocyte lineage-restricted progenitors (MEPs) of the homozygous mutant mice. In the bone marrows and spleens of the mutant mice, numbers of megakaryocytes were increased and numbers of erythroid progenitors were decreased. These abnormalities were reproducible in vitro in a coculture assay of MEPs with OP9 cells but eliminated by the retroviral expression of c-Myb in MEPs. The erythroid/megakaryocytic abnormalities were reconstituted in mice in vivo by transplantation of mutant mouse bone marrow cells. These results demonstrate that the transgene insertion into the c-myb gene far upstream regulatory region affects the gene expression at the stage of MEPs, leading to an imbalance between erythroid and megakaryocytic cells, and suggest that c-Myb is an essential regulator of the erythroid-megakaryocytic lineage bifurcation.
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Affiliation(s)
- Harumi Y Mukai
- Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba 305-8577, Japan
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39
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Kobayashi M, Yamamoto M. Nrf2-Keap1 regulation of cellular defense mechanisms against electrophiles and reactive oxygen species. ACTA ACUST UNITED AC 2006; 46:113-40. [PMID: 16887173 DOI: 10.1016/j.advenzreg.2006.01.007] [Citation(s) in RCA: 670] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Makoto Kobayashi
- JST-ERATO Environmental Response Project, Center for Tsukuba Advanced Research Alliance, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
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40
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Motohashi H, Katsuoka F, Miyoshi C, Uchimura Y, Saitoh H, Francastel C, Engel JD, Yamamoto M. MafG sumoylation is required for active transcriptional repression. Mol Cell Biol 2006; 26:4652-63. [PMID: 16738329 PMCID: PMC1489127 DOI: 10.1128/mcb.02193-05] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A straightforward mechanism for eliciting transcriptional repression would be to simply block the DNA binding site for activators. Such passive repression is often mediated by transcription factors that lack an intrinsic repressor activity. MafG is a bidirectional regulator of transcription, a repressor in its homodimeric state but an activator when heterodimerized with p45. Here, we report that MafG is conjugated to SUMO-2/3 in vivo. To clarify the possible physiological role(s) for sumoylation in regulating MafG activity, we evaluated mutant and wild-type MafG in transgenic mice and cultured cells. Whereas sumoylation-deficient MafG activated p45-dependent transcription normally and did not affect heterodimer activity, repression by the sumoylation-deficient MafG mutant was severely compromised in vivo. Furthermore, the SUMO-dependent repression activity of MafG was sensitive to histone deacetylase inhibition. Thus, repression by MafG is not achieved through simple passive repression by competing for the activator binding site but requires sumoylation, which then mediates transcriptional repression through recruitment of a repressor complex containing histone deacetylase activity.
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Affiliation(s)
- Hozumi Motohashi
- Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan.
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41
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Pouponnot C, Sii-Felice K, Hmitou I, Rocques N, Lecoin L, Druillennec S, Felder-Schmittbuhl MP, Eychène A. Cell context reveals a dual role for Maf in oncogenesis. Oncogene 2006; 25:1299-310. [PMID: 16247450 DOI: 10.1038/sj.onc.1209171] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Maf b-Zip transcription factors are involved in both terminal differentiation and oncogenesis. To investigate this apparent contradiction, we used two different primary cell types and performed an extensive analysis of transformation parameters induced by Maf proteins. We show that MafA and c-Maf are potent oncogenes in chicken embryo fibroblasts, while MafB appears weaker. We also provide the first evidence that MafA can confer growth factor independence and promote cell division at low density. Moreover, using MafA as a model, we identified several parameters that are critical for Maf transforming activities. Indeed, MafA ability to induce anchorage-independent cell growth was sensitive to culture conditions. In addition, the transforming activity of MafA was dependent on its phosphorylation state, since mutation on Ser65 impaired its ability to induce growth at low density and anchorage-independent growth. We next examined transforming activity of large Maf proteins in embryonic neuroretina cells, where they are known to induce differentiation. Unlike v-Jun, MafA, MafB and c-Maf did not show oncogenic activity in these cells. Moreover, they counteracted transformation induced by constitutive activation of the Ras/Raf/MEK pathway. Taken together, our results show that Maf proteins could display antagonistic functions in oncogenesis depending on the cellular context, and support a dual role for Maf as both oncogenes and tumor suppressor-like proteins.
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Affiliation(s)
- C Pouponnot
- Institut Curie, CNRS UMR 146, Centre Universitaire, Laboratoire 110, Orsay Cedex, France.
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42
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Igarashi K, Sun J. The heme-Bach1 pathway in the regulation of oxidative stress response and erythroid differentiation. Antioxid Redox Signal 2006; 8:107-18. [PMID: 16487043 DOI: 10.1089/ars.2006.8.107] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Heme--as a prosthetic group of proteins required for oxygen transport and storage, respiration, and biosynthetic pathways--is essential for practically all forms of life. Additionally, the degradation products of heme (i.e., carbon monoxide, biliverdin, and bilirubin) produced by the enzymatic actions of heme oxygenase (HO) and biliverdin reductase, possess various biological activities in vivo. In mammalian cells, heme also functions as an intracellular regulator of gene expression by virtue of its ability to bind to Bach1, a transcription factor that functions in association with small Maf proteins. Normally, such complexes function as repressors by binding to specific target sequences, the Maf recognition element (MARE), within enhancers of genes encoding proteins such as HO-1 and beta-globin. By binding to Bach1, heme induces selective removal of the repressor from the gene enhancers permitting subsequent occupancy of the MAREs by activators that, interestingly, also contain small Maf proteins. Thus small Maf proteins play dual functions in gene expression: complexes with Bach1 repress MARE-dependent gene expression, whereas heterodimers with NF-E2 p45 or related factors (Nrf1, Nrf2, and Nrf3) activate MARE-driven genes. By modulating the equilibrium of the small Maf heterodimer network, heme regulates expression of the cytoprotective enzyme HO-1 during the stress response and of beta-globin during erythroid differentiation. Implications of such heme-regulated gene expression in human diseases including atherosclerosis are discussed.
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Affiliation(s)
- Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan.
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43
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Massrieh W, Derjuga A, Doualla-Bell F, Ku CY, Sanborn BM, Blank V. Regulation of the MAFF transcription factor by proinflammatory cytokines in myometrial cells. Biol Reprod 2005; 74:699-705. [PMID: 16371591 DOI: 10.1095/biolreprod.105.045450] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The MAF (proto-)oncogene family of basic-leucine zipper transcription factors plays crucial roles in the control of mammalian gene expression and development. Here we analyzed the regulation of the human MAFF gene, coding for a small MAF transcription factor, in uterine smooth muscle cells. We found that MAFF transcript levels are induced by proinflammatory cytokines in PHM1-31 myometrial cells. We observed an important induction by interleukin 1 beta (IL1B) and a weaker upregulation by tumor necrosis factor (TNF), whereas interleukin 6 (IL6) treatment had no effect. Time course experiments revealed a rapid induction of MAFF transcripts within 30 min following IL1B treatment. The presence of actinomycin D inhibited the upregulation, suggesting that regulation of MAFF mRNA levels occurs at the transcriptional level. We generated a MAFF-specific antiserum and determined that MAFF protein was also induced by TNF and IL1B in PHM1-31 cells. In contrast, it was particularly interesting that the transcript and protein levels of the highly homologous MAFG and MAFK genes are not modulated by these cytokines. Our results suggest a possible specific role for MAFF in proinflammatory cytokine-mediated control of myometrial gene expression and provide the first link between a small MAF transcription factor and the inflammatory response.
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Affiliation(s)
- Wael Massrieh
- Lady Davis Institute for Medical Research, Department of Medicine, McGill University, Montreal, Quebec, Canada H3T 1E2
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44
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Katsuoka F, Motohashi H, Ishii T, Aburatani H, Engel JD, Yamamoto M. Genetic evidence that small maf proteins are essential for the activation of antioxidant response element-dependent genes. Mol Cell Biol 2005; 25:8044-51. [PMID: 16135796 PMCID: PMC1234339 DOI: 10.1128/mcb.25.18.8044-8051.2005] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
While small Maf proteins have been suggested to be essential for the Nrf2-mediated activation of antioxidant response element (ARE)-dependent genes, the extent of their requirement remains to be fully documented. To address this issue, we generated mafG::mafF double-mutant mice possessing MafK as the single available small Maf. Induction of the NAD(P)H:quinone oxidoreductase 1 (NQO1) gene was significantly impaired in double-mutant mice treated with butylated hydroxyanisole, while other ARE-dependent genes were less affected. Similarly, in a keap1-null background, where many of the ARE-dependent genes are constitutively activated in an Nrf2-dependent manner, only a subset of ARE-dependent genes, including NQO1, were sensitive to a simultaneous deficiency in MafG and MafF. Examination of single and double small maf mutant cells revealed that MafK also contributes to the induction of ARE-dependent genes. To obtain decisive evidence, we established mafG::mafK::mafF triple-mutant fibroblasts that completely lack small Mafs and turned out to be highly susceptible to oxidative stress. We found that induction in response to diethyl maleate was abolished in a wider range of ARE-dependent genes in the triple-mutant cells. These data explicitly demonstrate that small Mafs play critical roles in the inducible expression of a significant portion of ARE-dependent genes.
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Affiliation(s)
- Fumiki Katsuoka
- Center for TARA, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan
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45
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Schaak S, Cussac D, Labialle S, Mignotte V, Paris H. Cloning and functional characterization of the rat alpha2B-adrenergic receptor gene promoter region: Evidence for binding sites for erythropoiesis-related transcription factors GATA1 and NF-E2. Biochem Pharmacol 2005; 70:606-17. [PMID: 15993847 DOI: 10.1016/j.bcp.2005.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 05/23/2005] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
In the rat, the alpha2B-adrenergic receptor (alpha2B-AR) is encoded by the rat non-glycosylated (RNG) gene and is primarily expressed in the kidney, brain and liver of adult animals. High levels of alpha2B-AR are also found during fetal life in the placenta, liver and blood, where it is borne by cells of the erythropoietic lineage. As a first step to define the mechanisms responsible for the spatio-temporal pattern of alpha2B-AR expression, a genomic fragment containing 2.8 kb of the 5'-flanking region, the ORF and approximately 20 kb of the 3'-flanking region of the RNG gene was isolated. RNase protection assays performed on RNA from placenta or kidney using a series of riboprobes permitted to locate the transcription start site 372 bases upstream from the start codon. Transient transfection of various cells, including rat proximal tubule in primary culture, with constructs containing luciferase as a reporter gene demonstrated that: (i) the 5'-flanking region exhibited a strong and sense-dependent transcriptional activity and (ii) the 332 bp fragment (-732/-401 relative to the start codon), which lacks a TATA box but contains Sp1 sites, is sufficient to drive expression. Analysis of chromatin susceptibility to DNaseI digestion identified two hypersensitive sites (HS1 and HS2) located 1.7 and 1.0 kb, respectively, upstream from ATG and containing recognition sequences for erythroid transcription factors. EMSA showed specific binding of GATA1 and NF-E2 to these elements. Taken together, the results suggest that the chromatin environment in the vicinity of these boxes plays a critical role for alpha2B-AR expression during fetal life.
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Affiliation(s)
- Stéphane Schaak
- INSERM Unit 388, Institut Louis Bugnard, CHU Rangueil, Bâtiment L3, BP 84225, 31432 Toulouse Cedex 4, France
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Sii-Felice K, Pouponnot C, Gillet S, Lecoin L, Girault JA, Eychène A, Felder-Schmittbuhl MP. MafA transcription factor is phosphorylated by p38 MAP kinase. FEBS Lett 2005; 579:3547-54. [PMID: 15963504 DOI: 10.1016/j.febslet.2005.04.086] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 04/04/2005] [Accepted: 04/29/2005] [Indexed: 11/23/2022]
Abstract
Basic-leucine zipper transcription factors of the Maf family are key regulators of various developmental and differentiation processes. We previously reported that the phosphorylation status of MafA is a critical determinant of its biological functions. Using Western blot and mass spectrometry analysis, we now show that MafA is phosphorylated by p38 MAP kinase and identify three phosphoacceptor sites: threonine 113 and threonine 57, evolutionarily conserved residues located in the transcription activating domain, and serine 272. Mutation of these residues severely impaired MafA biological activity. Furthermore, we show that p38 also phosphorylates MafB and c-Maf. Together, these findings suggest that the p38 MAP kinase pathway is a novel regulator of large Maf transcription factors.
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Affiliation(s)
- Karine Sii-Felice
- UMR 146 CNRS-Institut Curie, Bâtiment 110, Centre Universitaire, 91405 Orsay Cedex, France
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Nakano M, Ohneda K, Yamamoto-Mukai H, Shimizu R, Ohneda O, Ohmura S, Suzuki M, Tsukamoto S, Yanagawa T, Yoshida H, Takakuwa Y, Yamamoto M. Transgenic over-expression of GATA-1 mutant lacking N-finger domain causes hemolytic syndrome in mouse erythroid cells. Genes Cells 2005; 10:47-62. [PMID: 15670213 DOI: 10.1111/j.1365-2443.2005.00814.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Transcription factor GATA-1 is essential for erythroid cell differentiation. GATA-binding motifs have been found in the regulatory regions of various erythroid-specific genes, suggesting that GATA-1 contributes to gene regulation during the entire process of erythropoiesis. A GATA-1 germ-line mutation results in embryonic lethality due to defective primitive erythropoiesis and GATA-1-null embryonic stem cells fails to differentiate beyond the proerythroblast stage. Therefore, the precise roles of GATA-1 in the later stages of erythropoiesis could not be clarified. Under the control of a GATA-1 gene hematopoietic regulatory domain, a GATA-1 mutant lacking the N-finger domain (DeltaNF mutant) was over-expressed in mice. These mice exhibited abnormal morphology in peripheral red blood cells (RBCs), reticulocytosis, splenomegaly, and erythroid hyperplasia, indicating compensated hemolysis. These mice were extremely sensitive to phenylhydrazine (PHZ), an agent that induces hemolysis, and their RBCs were osmotically fragile. Importantly, the hemolytic response to PHZ was partially restored by the simultaneous expression of wild-type GATA-1 with the DeltaNF mutant, supporting our contention that DeltaNF protein competitively inhibits the function of endogenous GATA-1. These data provide the first in vivo evidence that the NF domain contributes to the gene regulation that is critical for differentiation and survival of mature RBCs in postnatal erythropoiesis.
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Affiliation(s)
- Mayu Nakano
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
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Abstract
Megakaryocytes (MKs) expand and differentiate over several days in response to thrombopoietin (Tpo) before releasing innumerable blood platelets. The final steps in platelet assembly and release represent a unique cellular transformation that is orchestrated by a range of transcription factors, signaling molecules, and cytoskeletal elements. Here we review recent advances in the physiology and molecular basis of MK differentiation. Genome-wide approaches, including transcriptional profiling and proteomics, have been used to identify novel platelet products and differentiation markers. The extracellular factors, stromal-derived factor (SDF)-1 chemokine and fibroblast growth factor (FGF)-4 direct MK interactions with the bone marrow stroma and regulate cytokine-independent cell maturation. An abundance of bone marrow MKs induce pathologic states, including excessive bone formation and myelofibrosis, and the basis for these effects is now better appreciated. We review the status of transcription factors that control MK differentiation, with special emphasis on nuclear factor-erythroid 2 (NF-E2) and its two putative target genes, beta1-tubulin and 3-beta-hydroxysteroid reductase. MKs express steroid receptors and some estrogen ligands, which may constitute an autocrine loop in formation of proplatelets, the cytoplasmic protrusions within which nascent blood platelets are assembled. Finally, we summarize our own studies on cellular and molecular facets of proplatelet formation and place the findings within the context of outstanding questions about mechanisms of thrombopoiesis.
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Affiliation(s)
- H Schulze
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
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Katsuoka F, Motohashi H, Engel JD, Yamamoto M. Nrf2 transcriptionally activates the mafG gene through an antioxidant response element. J Biol Chem 2004; 280:4483-90. [PMID: 15574414 DOI: 10.1074/jbc.m411451200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Nrf2 accumulates in nuclei upon exposure to oxidative stress, heterodimerizes with a small Maf protein, and activates the transcription of stress target genes through antioxidant response elements (AREs). We found that diethyl maleate (DEM), a well known activator of Nrf2, induces one of the small Maf genes, mafG. To elucidate roles MafG might play in the oxidative stress response, we examined transcriptional regulation of the mouse mafG gene. MafG utilizes three independent first exons that are each spliced to second and third coding exons. Among the small maf genes, mafG showed the strongest response to DEM, and of the three first exons, the highest -fold induction was seen with the proximal first exon (Ic). Importantly, one ARE (Ic-ARE) is conserved in the promoter flanking exon Ic of the human and mouse mafG genes. The Nrf2/MafG heterodimer bound the Ic-ARE and activated transcription, whereas DEM failed to activate mafG in nrf2-null mutant cells. Chromatin immunoprecipitation further revealed that both Nrf2 and small Maf proteins associate with the Ic-ARE in vivo. These results demonstrate that mafG is itself an ARE-dependent gene that is regulated by an Nrf2/small Maf heterodimer and suggest the presence of an autoregulatory feedback pathway for mafG transcriptional regulation.
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Affiliation(s)
- Fumiki Katsuoka
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
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Lecoin L, Sii-Felice K, Pouponnot C, Eychène A, Felder-Schmittbuhl MP. Comparison of maf gene expression patterns during chick embryo development. Gene Expr Patterns 2004; 4:35-46. [PMID: 14678826 DOI: 10.1016/s1567-133x(03)00152-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Maf proteins are basic-leucine zipper transcription factors belonging to the AP1 superfamily. Several developmental processes require Maf proteins yet, the redundancy or complementarity of their respective roles in common processes has been only partially investigated. We present for the first time a complete comparative analysis of maf gene expression patterns in vertebrates. Expression of c-maf, mafB/kreisler, mafA/L-maf, mafF, mafG and mafK was analyzed by whole-mount in situ hybridization within chick embryos and their extraembryonic tissues ranging from embryonic day (E) 1 to 7. We carefully examined the extent of overlap between distinct maf genes and report that the developing lens, kidney, pancreas and apoptotic zones of limb buds show sustained co-expression of large maf genes. Small maf genes also exhibit overlap, for example in the dermomyotome. We also describe so far unidentified sites of maf gene expression. mafA is found in the developing neural tube and dorsal root ganglia. c-maf hybridization is detected in the neuroretina, the notochord and the endothelium of extraembryonic blood vessels.
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Affiliation(s)
- Laure Lecoin
- UMR 146 CNRS-Institut Curie, Bâtiment 110, Centre Universitaire, 91405 Orsay cedex, France
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