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Olcum M, Fan S, Rouhi L, Cheedipudi S, Cathcart B, Jeong HH, Zhao Z, Gurha P, Marian AJ. Genetic inactivation of β-catenin is salubrious, whereas its activation is deleterious in desmoplakin cardiomyopathy. Cardiovasc Res 2023; 119:2712-2728. [PMID: 37625794 PMCID: PMC11032201 DOI: 10.1093/cvr/cvad137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/13/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
AIMS Mutations in the DSP gene encoding desmoplakin, a constituent of the desmosomes at the intercalated discs (IDs), cause a phenotype that spans arrhythmogenic cardiomyopathy (ACM) and dilated cardiomyopathy. It is typically characterized by biventricular enlargement and dysfunction, myocardial fibrosis, cell death, and arrhythmias. The canonical wingless-related integration (cWNT)/β-catenin pathway is implicated in the pathogenesis of ACM. The β-catenin is an indispensable co-transcriptional regulator of the cWNT pathway and a member of the IDs. We genetically inactivated or activated β-catenin to determine its role in the pathogenesis of desmoplakin cardiomyopathy. METHODS AND RESULTS The Dsp gene was conditionally deleted in the 2-week-old post-natal cardiac myocytes using tamoxifen-inducible MerCreMer mice (Myh6-McmTam:DspF/F). The cWNT/β-catenin pathway was markedly dysregulated in the Myh6-McmTam:DspF/F cardiac myocytes, as indicated by a concomitant increase in the expression of cWNT/β-catenin target genes, isoforms of its key co-effectors, and the inhibitors of the pathway. The β-catenin was inactivated or activated upon inducible deletion of its transcriptional or degron domain, respectively, in the Myh6-McmTam:DspF/F cardiac myocytes. Genetic inactivation of β-catenin in the Myh6-McmTam:DspF/F mice prolonged survival, improved cardiac function, reduced cardiac arrhythmias, and attenuated myocardial fibrosis, and cell death caused by apoptosis, necroptosis, and pyroptosis, i.e. PANoptosis. In contrast, activation of β-catenin had the opposite effects. The deleterious and the salubrious effects were independent of changes in the expression levels of the cWNT target genes and were associated with changes in several molecular and biological pathways, including cell death programmes. CONCLUSION The cWNT/β-catenin was markedly dysregulated in the cardiac myocytes in a mouse model of desmoplakin cardiomyopathy. Inactivation of β-catenin attenuated, whereas its activation aggravated the phenotype, through multiple molecular pathways, independent of the cWNT transcriptional activity. Thus, suppression but not activation of β-catenin might be beneficial in desmoplakin cardiomyopathy.
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Affiliation(s)
- Melis Olcum
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Siyang Fan
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Leila Rouhi
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Sirisha Cheedipudi
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Benjamin Cathcart
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Hyun-Hwan Jeong
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhongming Zhao
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Priyatansh Gurha
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Ali J Marian
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
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2
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Gao R, Liang X, Cheedipudi S, Cordero J, Jiang X, Zhang Q, Caputo L, Günther S, Kuenne C, Ren Y, Bhattacharya S, Yuan X, Barreto G, Chen Y, Braun T, Evans SM, Sun Y, Dobreva G. Pioneering function of Isl1 in the epigenetic control of cardiomyocyte cell fate. Cell Res 2019; 29:486-501. [PMID: 31024170 PMCID: PMC6796926 DOI: 10.1038/s41422-019-0168-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 04/01/2019] [Indexed: 01/25/2023] Open
Abstract
Generation of widely differing and specialized cell types from a single totipotent zygote involves large-scale transcriptional changes and chromatin reorganization. Pioneer transcription factors play key roles in programming the epigenome and facilitating recruitment of additional regulatory factors during successive cell lineage specification and differentiation steps. Here we show that Isl1 acts as a pioneer factor driving cardiomyocyte lineage commitment by shaping the chromatin landscape of cardiac progenitor cells. Using an Isl1 hypomorphic mouse line which shows congenital heart defects, genome-wide profiling of Isl1 binding together with RNA- and ATAC-sequencing of cardiac progenitor cells and their derivatives, we uncover a regulatory network downstream of Isl1 that orchestrates cardiogenesis. Mechanistically, we show that Isl1 binds to compacted chromatin and works in concert with the Brg1-Baf60c-based SWI/SNF complex to promote permissive cardiac lineage-specific alterations in the chromatin landscape not only of genes with critical functions in cardiac progenitor cells, but also of cardiomyocyte structural genes that are highly expressed when Isl1 itself is no longer present. Thus, the Isl1/Brg1-Baf60c complex plays a crucial role in orchestrating proper cardiogenesis and in establishing epigenetic memory of cardiomyocyte fate commitment.
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Affiliation(s)
- Rui Gao
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- Department of Anatomy and Developmental Biology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Xingqun Liang
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, 200120, China
| | | | - Julio Cordero
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- Department of Anatomy and Developmental Biology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Xue Jiang
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, 200120, China
| | - Qingquan Zhang
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, 200120, China
| | - Luca Caputo
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Stefan Günther
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Carsten Kuenne
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Yonggang Ren
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- Department of Anatomy and Developmental Biology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - Xuejun Yuan
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Guillermo Barreto
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Yihan Chen
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, 200120, China
| | - Thomas Braun
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Sylvia M Evans
- Department of Medicine, Skaggs School of Pharmacy, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Yunfu Sun
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.
| | - Gergana Dobreva
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany.
- Department of Anatomy and Developmental Biology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
- European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
- Medical Faculty, University of Frankfurt, 60590, Frankfurt am Main, Germany.
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3
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Cheedipudi S, Gala HP, Puri D, Dhawan J. Identification of PRDM2 regulated genes in quiescent C2C12 myoblasts. Genom Data 2015; 6:264-6. [PMID: 26697392 PMCID: PMC4664777 DOI: 10.1016/j.gdata.2015.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 10/10/2015] [Accepted: 10/13/2015] [Indexed: 12/03/2022]
Abstract
Quiescent stem cells contribute to tissue homeostasis and repair in adult mammals. We identified a tumor suppressor PRDM2, as an epigenetic regulator induced in quiescent muscle stem cells as well as in cultured quiescent myoblasts. To delineate the functions of PRDM2 in muscle cells, we compared the gene expression profiles of control and PRDM2 knockdown myoblasts in growing, differentiating and quiescent conditions (GEO accession number: GSE 58676). To identify the direct targets of PRDM2 and the promoters co-associated with H3K9me2 (mark catalyzed by PRDM2), ChIP-Chip analysis was performed (GSE58748). In this report we discuss in detail the methodology used to identify PRDM2 regulated genes and classify them into potential direct and indirect targets.
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Affiliation(s)
- Sirisha Cheedipudi
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India ; Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | - Hardik P Gala
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India ; Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | - Deepika Puri
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India
| | - Jyotsna Dhawan
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India ; Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
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4
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Caputo L, Witzel HR, Kolovos P, Cheedipudi S, Looso M, Mylona A, van IJcken WFJ, Laugwitz KL, Evans SM, Braun T, Soler E, Grosveld F, Dobreva G. The Isl1/Ldb1 Complex Orchestrates Genome-wide Chromatin Organization to Instruct Differentiation of Multipotent Cardiac Progenitors. Cell Stem Cell 2015; 17:287-99. [PMID: 26321200 DOI: 10.1016/j.stem.2015.08.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 07/08/2015] [Accepted: 08/06/2015] [Indexed: 01/21/2023]
Abstract
Cardiac stem/progenitor cells hold great potential for regenerative therapies; however, the mechanisms regulating their expansion and differentiation remain insufficiently defined. Here we show that Ldb1 is a central regulator of genome organization in cardiac progenitor cells, which is crucial for cardiac lineage differentiation and heart development. We demonstrate that Ldb1 binds to the key regulator of cardiac progenitors, Isl1, and protects it from degradation. Furthermore, the Isl1/Ldb1 complex promotes long-range enhancer-promoter interactions at the loci of the core cardiac transcription factors Mef2c and Hand2. Chromosome conformation capture followed by sequencing identified specific Ldb1-mediated interactions of the Isl1/Ldb1 responsive Mef2c anterior heart field enhancer with genes that play key roles in cardiac progenitor cell function and cardiovascular development. Importantly, the expression of these genes was downregulated upon Ldb1 depletion and Isl1/Ldb1 haplodeficiency. In conclusion, the Isl1/Ldb1 complex orchestrates a network for heart-specific transcriptional regulation and coordination in three-dimensional space during cardiogenesis.
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Affiliation(s)
- Luca Caputo
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Hagen R Witzel
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Petros Kolovos
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands
| | - Sirisha Cheedipudi
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Mario Looso
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Athina Mylona
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands; School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, Kent CT1 1QU, UK
| | | | - Karl-Ludwig Laugwitz
- I. Medical Department, Cardiology, Klinikum rechts der Isar, Technical University, 81675 Munich, Germany
| | - Sylvia M Evans
- Department of Medicine, Skaggs School of Pharmacy, University of California, San Diego, La Jolla, CA 92093, USA
| | - Thomas Braun
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Eric Soler
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands; Laboratory of Molecular Hematopoiesis, CEA/DSV/iRCM/LHM, INSERM UMR967, 92265 Fontenay-aux-Roses, France; Laboratory of Excellence GR-Ex, 75015, Paris, France
| | - Frank Grosveld
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands
| | - Gergana Dobreva
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany; Medical Faculty, University of Frankfurt, 60590 Frankfurt am Main, Germany.
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5
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Cheedipudi S, Puri D, Saleh A, Gala HP, Rumman M, Pillai MS, Sreenivas P, Arora R, Sellathurai J, Schrøder HD, Mishra RK, Dhawan J. A fine balance: epigenetic control of cellular quiescence by the tumor suppressor PRDM2/RIZ at a bivalent domain in the cyclin a gene. Nucleic Acids Res 2015; 43:6236-56. [PMID: 26040698 PMCID: PMC4513853 DOI: 10.1093/nar/gkv567] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 05/19/2015] [Indexed: 12/20/2022] Open
Abstract
Adult stem cell quiescence is critical to ensure regeneration while minimizing tumorigenesis. Epigenetic regulation contributes to cell cycle control and differentiation, but few regulators of the chromatin state in quiescent cells are known. Here we report that the tumor suppressor PRDM2/RIZ, an H3K9 methyltransferase, is enriched in quiescent muscle stem cells invivo and controls reversible quiescence in cultured myoblasts. We find that PRDM2 associates with >4400 promoters in G0 myoblasts, 55% of which are also marked with H3K9me2 and enriched for myogenic, cell cycle and developmental regulators. Knockdown of PRDM2 alters histone methylation at key promoters such as Myogenin and CyclinA2 (CCNA2), and subverts the quiescence program via global de-repression of myogenesis, and hyper-repression of the cell cycle. Further, PRDM2 acts upstream of the repressive PRC2 complex in G0. We identify a novel G0-specific bivalent chromatin domain in the CCNA2 locus. PRDM2 protein interacts with the PRC2 protein EZH2 and regulates its association with the bivalent domain in the CCNA2 gene. Our results suggest that induction of PRDM2 in G0 ensures that two antagonistic programs—myogenesis and the cell cycle—while stalled, are poised for reactivation. Together, these results indicate that epigenetic regulation by PRDM2 preserves key functions of the quiescent state, with implications for stem cell self-renewal.
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Affiliation(s)
- Sirisha Cheedipudi
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India Max Planck Institute for Heart and Lung Research, Bad Nauheim 61231, Germany
| | - Deepika Puri
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India Max Planck Institute of Immunobiology and Epigenetics, Freiburg D-79108, Germany
| | - Amena Saleh
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India Manipal University, Manipal 576104 India
| | - Hardik P Gala
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | - Mohammed Rumman
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India Manipal University, Manipal 576104 India
| | - Malini S Pillai
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India
| | - Prethish Sreenivas
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | - Reety Arora
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India
| | - Jeeva Sellathurai
- Institute of Clinical Research, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense 5000 C, Denmark
| | - Henrik Daa Schrøder
- Institute of Clinical Research, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense 5000 C, Denmark
| | - Rakesh K Mishra
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | - Jyotsna Dhawan
- Institute for Stem Cell Biology and Regenerative Medicine, National Center for Biological Sciences, GKVK Post, Bellary Road, Bangalore 560065, India Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
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6
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Abstract
During embryonic development a large number of widely differing and specialized cell types with identical genomes are generated from a single totipotent zygote. Tissue specific transcription factors cooperate with epigenetic modifiers to establish cellular identity in differentiated cells and epigenetic regulatory mechanisms contribute to the maintenance of distinct chromatin states and cell-type specific gene expression patterns, a phenomenon referred to as epigenetic memory. This is accomplished via the stable maintenance of various epigenetic marks through successive rounds of cell division. Preservation of DNA methylation patterns is a well-established mechanism of epigenetic memory, but more recently it has become clear that many other epigenetic modifications can also be maintained following DNA replication and cell division. In this review, we present an overview of the current knowledge regarding the role of histone lysine methylation in the establishment and maintenance of stable epigenetic states.
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Affiliation(s)
- Sirisha Cheedipudi
- Origin of Cardiac Cell Lineages Group, Max Planck Institute for Heart and Lung Research Bad Nauheim, Germany ; Medical Faculty, J. W. Goethe University Frankfurt Frankfurt, Germany
| | - Oriana Genolet
- Origin of Cardiac Cell Lineages Group, Max Planck Institute for Heart and Lung Research Bad Nauheim, Germany ; Medical Faculty, J. W. Goethe University Frankfurt Frankfurt, Germany
| | - Gergana Dobreva
- Origin of Cardiac Cell Lineages Group, Max Planck Institute for Heart and Lung Research Bad Nauheim, Germany ; Medical Faculty, J. W. Goethe University Frankfurt Frankfurt, Germany
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7
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Subramaniam S, Sreenivas P, Cheedipudi S, Reddy VR, Shashidhara LS, Chilukoti RK, Mylavarapu M, Dhawan J. Distinct transcriptional networks in quiescent myoblasts: a role for Wnt signaling in reversible vs. irreversible arrest. PLoS One 2013; 8:e65097. [PMID: 23755177 PMCID: PMC3670900 DOI: 10.1371/journal.pone.0065097] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 04/23/2013] [Indexed: 01/09/2023] Open
Abstract
Most cells in adult mammals are non-dividing: differentiated cells exit the cell cycle permanently, but stem cells exist in a state of reversible arrest called quiescence. In damaged skeletal muscle, quiescent satellite stem cells re-enter the cell cycle, proliferate and subsequently execute divergent programs to regenerate both post-mitotic myofibers and quiescent stem cells. The molecular basis for these alternative programs of arrest is poorly understood. In this study, we used an established myogenic culture model (C2C12 myoblasts) to generate cells in alternative states of arrest and investigate their global transcriptional profiles. Using cDNA microarrays, we compared G0 myoblasts with post-mitotic myotubes. Our findings define the transcriptional program of quiescent myoblasts in culture and establish that distinct gene expression profiles, especially of tumour suppressor genes and inhibitors of differentiation characterize reversible arrest, distinguishing this state from irreversibly arrested myotubes. We also reveal the existence of a tissue-specific quiescence program by comparing G0 C2C12 myoblasts to isogenic G0 fibroblasts (10T1/2). Intriguingly, in myoblasts but not fibroblasts, quiescence is associated with a signature of Wnt pathway genes. We provide evidence that different levels of signaling via the canonical Wnt pathway characterize distinct cellular states (proliferation vs. quiescence vs. differentiation). Moderate induction of Wnt signaling in quiescence is associated with critical properties such as clonogenic self-renewal. Exogenous Wnt treatment subverts the quiescence program and negatively affects clonogenicity. Finally, we identify two new quiescence-induced regulators of canonical Wnt signaling, Rgs2 and Dkk3, whose induction in G0 is required for clonogenic self-renewal. These results support the concept that active signal-mediated regulation of quiescence contributes to stem cell properties, and have implications for pathological states such as cancer and degenerative disease.
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Affiliation(s)
| | - Prethish Sreenivas
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Sirisha Cheedipudi
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | | | | | | | | | - Jyotsna Dhawan
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- * E-mail:
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8
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Sellathurai J, Cheedipudi S, Dhawan J, Schrøder HD. A novel in vitro model for studying quiescence and activation of primary isolated human myoblasts. PLoS One 2013; 8:e64067. [PMID: 23717533 PMCID: PMC3662676 DOI: 10.1371/journal.pone.0064067] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 04/09/2013] [Indexed: 01/01/2023] Open
Abstract
Skeletal muscle stem cells, satellite cells, are normally quiescent but become activated upon muscle injury. Recruitment of resident satellite cells may be a useful strategy for treatment of muscle disorders, but little is known about gene expression in quiescent human satellite cells or the mechanisms involved in their early activation. We have developed a method to induce quiescence in purified primary human myoblasts isolated from healthy individuals. Analysis of the resting state showed absence of BrdU incorporation and lack of KI67 expression, as well as the extended kinetics during synchronous reactivation into the cell cycle, confirming arrest in the G0 phase. Reactivation studies showed that the majority (>95%) of the G0 arrested cells were able to re-enter the cell cycle, confirming reversibility of arrest. Furthermore, a panel of important myogenic factors showed expression patterns similar to those reported for mouse satellite cells in G0, reactivated and differentiated cultures, supporting the applicability of the human model. In addition, gene expression profiling showed that a large number of genes (4598) were differentially expressed in cells activated from G0 compared to long term exponentially proliferating cultures normally used for in vitro studies. Human myoblasts cultured through many passages inevitably consist of a mixture of proliferating and non-proliferating cells, while cells activated from G0 are in a synchronously proliferating phase, and therefore may be a better model for in vivo proliferating satellite cells. Furthermore, the temporal propagation of proliferation in these synchronized cultures resembles the pattern seen in vivo during regeneration. We therefore present this culture model as a useful and novel condition for molecular analysis of quiescence and reactivation of human myoblasts.
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Affiliation(s)
- Jeeva Sellathurai
- Institute of Clinical Research, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, Denmark
| | | | - Jyotsna Dhawan
- Institute for Stem Cell Biology and Regenerative Medicine (InStem), National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Henrik Daa Schrøder
- Institute of Clinical Research, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, Denmark
- Department of Clinical Pathology, Odense University Hospital, Odense, Denmark
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9
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Krishna S, Nair A, Cheedipudi S, Poduval D, Dhawan J, Palakodeti D, Ghanekar Y. Deep sequencing reveals unique small RNA repertoire that is regulated during head regeneration in Hydra magnipapillata. Nucleic Acids Res 2012; 41:599-616. [PMID: 23166307 PMCID: PMC3592418 DOI: 10.1093/nar/gks1020] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Small non-coding RNAs such as miRNAs, piRNAs and endo-siRNAs fine-tune gene expression through post-transcriptional regulation, modulating important processes in development, differentiation, homeostasis and regeneration. Using deep sequencing, we have profiled small non-coding RNAs in Hydra magnipapillata and investigated changes in small RNA expression pattern during head regeneration. Our results reveal a unique repertoire of small RNAs in hydra. We have identified 126 miRNA loci; 123 of these miRNAs are unique to hydra. Less than 50% are conserved across two different strains of Hydra vulgaris tested in this study, indicating a highly diverse nature of hydra miRNAs in contrast to bilaterian miRNAs. We also identified siRNAs derived from precursors with perfect stem-loop structure and that arise from inverted repeats. piRNAs were the most abundant small RNAs in hydra, mapping to transposable elements, the annotated transcriptome and unique non-coding regions on the genome. piRNAs that map to transposable elements and the annotated transcriptome display a ping-pong signature. Further, we have identified several miRNAs and piRNAs whose expression is regulated during hydra head regeneration. Our study defines different classes of small RNAs in this cnidarian model system, which may play a role in orchestrating gene expression essential for hydra regeneration.
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Affiliation(s)
- Srikar Krishna
- Institute for Stem Cell Biology and Regenerative Medicine, National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore 560065, India
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Sambasivan R, Cheedipudi S, Pasupuleti N, Saleh A, Pavlath GK, Dhawan J. The small chromatin-binding protein p8 coordinates the association of anti-proliferative and pro-myogenic proteins at the myogenin promoter. J Cell Sci 2009; 122:3481-91. [PMID: 19723804 PMCID: PMC2746131 DOI: 10.1242/jcs.048678] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2009] [Indexed: 01/09/2023] Open
Abstract
Quiescent muscle progenitors called satellite cells persist in adult skeletal muscle and, upon injury to muscle, re-enter the cell cycle and either undergo self-renewal or differentiate to regenerate lost myofibers. Using synchronized cultures of C2C12 myoblasts to model these divergent programs, we show that p8 (also known as Nupr1), a G1-induced gene, negatively regulates the cell cycle and promotes myogenic differentiation. p8 is a small chromatin protein related to the high mobility group (HMG) family of architectural factors and binds to histone acetyltransferase p300 (p300, also known as CBP). We confirm this interaction and show that p300-dependent events (Myc expression, global histone acetylation and post-translational acetylation of the myogenic regulator MyoD) are all affected in p8-knockdown myoblasts, correlating with repression of MyoD target-gene expression and severely defective differentiation. We report two new partners for p8 that support a role in muscle-specific gene regulation: p68 (Ddx5), an RNA helicase reported to bind both p300 and MyoD, and MyoD itself. We show that, similar to MyoD and p300, p8 and p68 are located at the myogenin promoter, and that knockdown of p8 compromises chromatin association of all four proteins. Thus, p8 represents a new node in a chromatin regulatory network that coordinates myogenic differentiation with cell-cycle exit.
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