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Seiliez I, Froehlich JM, Marandel L, Gabillard JC, Biga PR. Evolutionary history and epigenetic regulation of the three paralogous pax7 genes in rainbow trout. Cell Tissue Res 2014; 359:715-27. [PMID: 25487404 DOI: 10.1007/s00441-014-2060-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 11/06/2014] [Indexed: 01/24/2023]
Abstract
The extraordinary muscle growth potential of teleost fish, particular those of the Salmoninae clade, elicits questions about the regulation of the relatively highly conserved transcription factors of the myogenic program. The pseudotetraploid nature of the salmonid genome adds another layer of regulatory complexity that must be reconciled with epigenetic data to improve our understanding of the achievement of lifelong muscle growth in these fish. We identify three paralogous pax7 genes (pax7a1, pax7a2 and pax7b) in the rainbow trout genome. During in vitro myogenesis, pax7a1 transcripts remain stable, whereas pax7a2 and pax7b mRNAs increase in abundance, similarly to myogenin mRNAs but in contrast to the expression pattern of the mammalian ortholog. We also profile the distribution of repressive H3K27me3 and H3K9me3 and permissive H3K4me3 marks during in vitro myogenesis across these loci and find that pax7a2 expression is associated with decreased H3K27 trimethylation, whereas pax7b expression is correlated with decreased H3K9me3 and H3K27me3. These data link the unique differential expression of pax7 paralogs with epigenetic histone modifications in a vertebrate species displaying growth divergent from that of mammals and highlight an important divergence in the regulatory mechanisms of pax7 expression among vertebrates. The system described here provides a more comprehensive picture of the combinatorial control mechanisms orchestrating skeletal muscle growth in a salmonid, leading to a better understanding of myogenesis in this species and across Vertebrata more generally.
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Affiliation(s)
- Iban Seiliez
- INRA, UR1067 Nutrition Métabolisme Aquaculture, F-64310, St-Pée-sur-Nivelle, France
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202
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Segalés J, Perdiguero E, Muñoz-Cánoves P. Epigenetic control of adult skeletal muscle stem cell functions. FEBS J 2014; 282:1571-88. [PMID: 25251895 DOI: 10.1111/febs.13065] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 12/12/2022]
Abstract
Skeletal muscle regeneration in the adult (de novo myogenesis) depends on a resident population of muscle stem cells (satellite cells) that are normally quiescent. In response to injury or stress, satellite cells are activated and expand as myoblast cells that differentiate and fuse to form new muscle fibers or return to quiescence to maintain the stem cell pool (self-renewal). Satellite cell-dependent myogenesis is a well-characterized multi-step process orchestrated by muscle-specific transcription factors, such as Pax3/Pax7 and members of the MyoD family of muscle regulatory factors, and epigenetically controlled by mechanisms such as DNA methylation, covalent modification of histones and non-coding RNAs. Recent results from next-generation genome-wide sequencing have increased our understanding about the highly intricate layers of epigenetic regulation involved in satellite cell maintenance, activation, differentiation and self-renewal, and their cross-talk with the muscle-specific transcriptional machinery.
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Affiliation(s)
- Jessica Segalés
- Cell Biology Group, Department of Experimental and Health Sciences, Pompeu Fabra University, Center for Networked Biomedical Research on Neurodegenerative Diseases, Barcelona, Spain
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203
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Im GI, Shin KJ. Epigenetic approaches to regeneration of bone and cartilage from stem cells. Expert Opin Biol Ther 2014; 15:181-93. [DOI: 10.1517/14712598.2015.960838] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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204
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Liu J, Wang L, Liu W, Li Q, Jin Z, Jin Y. Dental follicle cells rescue the regenerative capacity of periodontal ligament stem cells in an inflammatory microenvironment. PLoS One 2014; 9:e108752. [PMID: 25275580 PMCID: PMC4183515 DOI: 10.1371/journal.pone.0108752] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/11/2014] [Indexed: 12/22/2022] Open
Abstract
Aims Periodontal ligament stem cells (PDLSCs) are one of the best candidates for periodontal regeneration. Their function could be impaired in periodontitis microenvironment. Dental follicle cells (DFCs), serving as precursor cells and mesenchymal stem cells, have intimate connection with PDLSCs. However, it is still unknown whether DFCs could provide a favorable microenvironment to improve the proliferation and differentiation capacity of PDLSCs from healthy subjects (HPDLSCs) and patients diagnosed with periodontitis (PPDLSCs). Methods HPDLSCs, PPDLSCs and DFCs were harvested and identified using microscopic and flow cytometric analysis. Then, the coculture systems of DFCs/HPDLSCs and DFCs/PPDLSCs were established with 0.4 µm transwell, in which all the detection indexs were obtained from HPDLSCs and PPDLSCs. The expression of stemness-associated genes was detected by real-time PCR, and the proliferation ability was assessed using colony formation and cell cycle assays. The osteogenic differentiation capacity was evaluated by real-time PCR, western blot, ALP activity, Alizarin Red S staining and calcium level analysis, while the adipogenic differentiation capacity was determined by real-time PCR and Oil Red O staining. The cell sheet formation in vitro was observed by HE staining and SEM, and the implantation effect in vivo was evaluated using HE staining and Masson’s trichrome staining. Results PPDLSCs had a greater proliferation capability but lower osteogenic and adipogenic potential than HPDLSCs. DFCs enhanced the proliferation and osteogenic/adipogenic differentiation of HPDLSCs and PPDLSCs to different degrees. Moreover, coculture with DFCs increased cell layers and extracellular matrix of HPDLSCs/PPDLSCs cell sheets in vitro and improved periodontal regeneration by HPDLSCs/PPDLSCs in vivo. Conclusions Our data suggest that the function of PPDLSCs could be damaged in the periodontitis microenvironment. DFCs appear to enhance the self-renewal and multi-differentiation capacity of both HPDLSCs and PPDLSCs, which indicates that DFCs could provide a beneficial microenvironment for periodontal regeneration using PDLSCs.
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Affiliation(s)
- Jia Liu
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
- State Key Laboratory of Military Stomatology, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Liying Wang
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
- State Key Laboratory of Military Stomatology, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Wenjia Liu
- State Key Laboratory of Military Stomatology, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
- Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Qiang Li
- State Key Laboratory of Military Stomatology, Department of General Dentistry & Emergency, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Zuolin Jin
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
- * E-mail: (ZJ); (YJ)
| | - Yan Jin
- State Key Laboratory of Military Stomatology, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
- Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi’an, Shaanxi, China
- * E-mail: (ZJ); (YJ)
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205
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STAT3 signaling controls satellite cell expansion and skeletal muscle repair. Nat Med 2014; 20:1182-6. [PMID: 25194572 DOI: 10.1038/nm.3656] [Citation(s) in RCA: 274] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 07/10/2014] [Indexed: 12/24/2022]
Abstract
The progressive loss of muscle regenerative capacity with age or disease results in part from a decline in the number and function of satellite cells, the direct cellular contributors to muscle repair. However, little is known about the molecular effectors underlying satellite cell impairment and depletion. Elevated levels of inflammatory cytokines, including interleukin-6 (IL-6), are associated with both age-related and muscle-wasting conditions. The levels of STAT3, a downstream effector of IL-6, are also elevated with muscle wasting, and STAT3 has been implicated in the regulation of self-renewal and stem cell fate in several tissues. Here we show that IL-6-activated Stat3 signaling regulates satellite cell behavior, promoting myogenic lineage progression through myogenic differentiation 1 (Myod1) regulation. Conditional ablation of Stat3 in Pax7-expressing satellite cells resulted in their increased expansion during regeneration, but compromised myogenic differentiation prevented the contribution of these cells to regenerating myofibers. In contrast, transient Stat3 inhibition promoted satellite cell expansion and enhanced tissue repair in both aged and dystrophic muscle. The effects of STAT3 inhibition on cell fate and proliferation were conserved in human myoblasts. The results of this study indicate that pharmacological manipulation of STAT3 activity can be used to counteract the functional exhaustion of satellite cells in pathological conditions, thereby maintaining the endogenous regenerative response and ameliorating muscle-wasting diseases.
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206
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Abstract
The cell of origin remains debated for the aggressive childhood cancer alveolar rhabdomyosarcoma (aRMS). Abraham et al. used conditional mouse models of aRMS to activate the Pax3:Foxo1 fusion oncogene and inactivate p53 in several lineages of early development. The results reveal that the tumor cell of origin significantly influences tumor sensitivity to targeted therapies. Furthermore, the transcriptional regulation of the Pax3:Foxo1a locus varies by lineage of origin. These discoveries led to the identification of the histone deacetylase inhibitor entinostat as a potential agent for pharmacological intervention. Lineage or cell of origin of cancers is often unknown and thus is not a consideration in therapeutic approaches. Alveolar rhabdomyosarcoma (aRMS) is an aggressive childhood cancer for which the cell of origin remains debated. We used conditional genetic mouse models of aRMS to activate the pathognomonic Pax3:Foxo1 fusion oncogene and inactivate p53 in several stages of prenatal and postnatal muscle development. We reveal that lineage of origin significantly influences tumor histomorphology and sensitivity to targeted therapeutics. Furthermore, we uncovered differential transcriptional regulation of the Pax3:Foxo1 locus by tumor lineage of origin, which led us to identify the histone deacetylase inhibitor entinostat as a pharmacological agent for the potential conversion of Pax3:Foxo1-positive aRMS to a state akin to fusion-negative RMS through direct transcriptional suppression of Pax3:Foxo1.
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Ciarapica R, De Salvo M, Carcarino E, Bracaglia G, Adesso L, Leoncini PP, Dall'Agnese A, Walters ZS, Verginelli F, De Sio L, Boldrini R, Inserra A, Bisogno G, Rosolen A, Alaggio R, Ferrari A, Collini P, Locatelli M, Stifani S, Screpanti I, Rutella S, Yu Q, Marquez VE, Shipley J, Valente S, Mai A, Miele L, Puri PL, Locatelli F, Palacios D, Rota R. The Polycomb group (PcG) protein EZH2 supports the survival of PAX3-FOXO1 alveolar rhabdomyosarcoma by repressing FBXO32 (Atrogin1/MAFbx). Oncogene 2014; 33:4173-84. [PMID: 24213577 DOI: 10.1038/onc.2013.471] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 09/11/2013] [Accepted: 09/30/2013] [Indexed: 12/20/2022]
Abstract
The Polycomb group (PcG) proteins regulate stem cell differentiation via the repression of gene transcription, and their deregulation has been widely implicated in cancer development. The PcG protein Enhancer of Zeste Homolog 2 (EZH2) works as a catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) by methylating lysine 27 on histone H3 (H3K27me3), a hallmark of PRC2-mediated gene repression. In skeletal muscle progenitors, EZH2 prevents an unscheduled differentiation by repressing muscle-specific gene expression and is downregulated during the course of differentiation. In rhabdomyosarcoma (RMS), a pediatric soft-tissue sarcoma thought to arise from myogenic precursors, EZH2 is abnormally expressed and its downregulation in vitro leads to muscle-like differentiation of RMS cells of the embryonal variant. However, the role of EZH2 in the clinically aggressive subgroup of alveolar RMS, characterized by the expression of PAX3-FOXO1 oncoprotein, remains unknown. We show here that EZH2 depletion in these cells leads to programmed cell death. Transcriptional derepression of F-box protein 32 (FBXO32) (Atrogin1/MAFbx), a gene associated with muscle homeostasis, was evidenced in PAX3-FOXO1 RMS cells silenced for EZH2. This phenomenon was associated with reduced EZH2 occupancy and H3K27me3 levels at the FBXO32 promoter. Simultaneous knockdown of FBXO32 and EZH2 in PAX3-FOXO1 RMS cells impaired the pro-apoptotic response, whereas the overexpression of FBXO32 facilitated programmed cell death in EZH2-depleted cells. Pharmacological inhibition of EZH2 by either 3-Deazaneplanocin A or a catalytic EZH2 inhibitor mirrored the phenotypic and molecular effects of EZH2 knockdown in vitro and prevented tumor growth in vivo. Collectively, these results indicate that EZH2 is a key factor in the proliferation and survival of PAX3-FOXO1 alveolar RMS cells working, at least in part, by repressing FBXO32. They also suggest that the reducing activity of EZH2 could represent a novel adjuvant strategy to eradicate high-risk PAX3-FOXO1 alveolar RMS.
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Affiliation(s)
- R Ciarapica
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - M De Salvo
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | | | - G Bracaglia
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - L Adesso
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - P P Leoncini
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | | | - Z S Walters
- Sarcoma Molecular Pathology, Divisions of Molecular Pathology and Cancer Therapeutics, The Institute of Cancer Research, Sutton, UK
| | - F Verginelli
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - L De Sio
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - R Boldrini
- Department of Pathology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - A Inserra
- Department of Surgery, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - G Bisogno
- Department of Pediatrics, Oncohematology Unit, University of Padova, Padova, Italy
| | - A Rosolen
- Department of Pediatrics, Oncohematology Unit, University of Padova, Padova, Italy
| | - R Alaggio
- Medicine DIMED, Pathology Unit, University of Padova, Padova, Italy
| | - A Ferrari
- Pediatric Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy
| | - P Collini
- Anatomic Pathology Unit 2, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy
| | - M Locatelli
- Scientific Directorate, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - S Stifani
- Centre for Neuronal Survival, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - I Screpanti
- Department of Molecular Medicine, Sapienza University, Roma, Italy
| | - S Rutella
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
| | - Q Yu
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore
| | - V E Marquez
- Chemical Biology Laboratory, Frederick National Laboratory for Cancer Research, CCR, National Cancer Institute, NIH, Frederick, MD, USA
| | - J Shipley
- Sarcoma Molecular Pathology, Divisions of Molecular Pathology and Cancer Therapeutics, The Institute of Cancer Research, Sutton, UK
| | - S Valente
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza University, Roma, Italy
| | - A Mai
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza University, Roma, Italy
| | - L Miele
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - P L Puri
- 1] IRCCS Fondazione Santa Lucia, Roma, Italy [2] Muscle Development and Regeneration Program, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - F Locatelli
- 1] Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy [2] Dipartimento di Scienze Pediatriche, Università di Pavia, Pavia, Italy
| | - D Palacios
- IRCCS Fondazione Santa Lucia, Roma, Italy
| | - R Rota
- Department of Oncohematology, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy
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Montagna C, Di Giacomo G, Rizza S, Cardaci S, Ferraro E, Grumati P, De Zio D, Maiani E, Muscoli C, Lauro F, Ilari S, Bernardini S, Cannata S, Gargioli C, Ciriolo MR, Cecconi F, Bonaldo P, Filomeni G. S-nitrosoglutathione reductase deficiency-induced S-nitrosylation results in neuromuscular dysfunction. Antioxid Redox Signal 2014; 21:570-87. [PMID: 24684653 PMCID: PMC4086474 DOI: 10.1089/ars.2013.5696] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
AIMS Nitric oxide (NO) production is implicated in muscle contraction, growth and atrophy, and in the onset of neuropathy. However, many aspects of the mechanism of action of NO are not yet clarified, mainly regarding its role in muscle wasting. Notably, whether NO production-associated neuromuscular atrophy depends on tyrosine nitration or S-nitrosothiols (SNOs) formation is still a matter of debate. Here, we aim at assessing this issue by characterizing the neuromuscular phenotype of S-nitrosoglutathione reductase-null (GSNOR-KO) mice that maintain the capability to produce NO, but are unable to reduce SNOs. RESULTS We demonstrate that, without any sign of protein nitration, young GSNOR-KO mice show neuromuscular atrophy due to loss of muscle mass, reduced fiber size, and neuropathic behavior. In particular, GSNOR-KO mice show a significant decrease in nerve axon number, with the myelin sheath appearing disorganized and reduced, leading to a dramatic development of a neuropathic phenotype. Mitochondria appear fragmented and depolarized in GSNOR-KO myofibers and myotubes, conditions that are reverted by N-acetylcysteine treatment. Nevertheless, although atrogene transcription is induced, and bulk autophagy activated, no removal of damaged mitochondria is observed. These events, alongside basal increase of apoptotic markers, contribute to persistence of a neuropathic and myopathic state. INNOVATION Our study provides the first evidence that GSNOR deficiency, which affects exclusively SNOs reduction without altering nitrotyrosine levels, results in a clinically relevant neuromuscular phenotype. CONCLUSION These findings provide novel insights into the involvement of GSNOR and S-nitrosylation in neuromuscular atrophy and neuropathic pain that are associated with pathological states; for example, diabetes and cancer.
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209
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Hui T, A P, Zhao Y, Wang C, Gao B, Zhang P, Wang J, Zhou X, Ye L. EZH2, a potential regulator of dental pulp inflammation and regeneration. J Endod 2014; 40:1132-8. [PMID: 25069920 DOI: 10.1016/j.joen.2014.01.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/22/2013] [Accepted: 01/21/2014] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Dental pulp has limited capability to regenerate, which happens in the early stage of pulpitis. An ambiguous relationship exists; inflammation may impair or support pulp regeneration. Epigenetics, which is involved in cell proliferation and inflammation, could regulate human dental pulp cell (HDPCs) regeneration. The aim of this study was to determine the role of the epigenetic mark, enhancer of zeste homolog 2 (EZH2), in the inflammation, proliferation, and regeneration of dental pulp. We used trimethylated histone H3 lysine 27(H3K27me3) and its lysine demethylase 6B (KDM6B) to monitor functional effects of altered EZH2 levels. METHODS We detected epigenetic marks (EZH2, H3K27me3, and KDM6B) in pulp tissue by immunohistochemistry and immunofluorescence. EZH2 levels in HDPCs in inflammatory responses or differentiation were analyzed by quantitative polymerase chain reaction and Western blot. Quantitative polymerase chain reaction was used to assess the effects of EZH2 inhibition on interleukins in HDPCs upon tumor necrosis factor alpha stimulation. Cell proliferation was tested by cell counting kit-8, cell cycle, and apoptosis analysis. HDPC differentiation was investigated by quantitative polymerase chain reaction, alkaline phosphatase activity, and oil red O staining. RESULTS EZH2 and H3K27me3 were decreased, whereas KDM6B was increased in infected pulp tissue and cells, which were similar to HDPC differentiation. EZH2 inhibition suppressed IL-1b, IL-6, and IL-8 messenger RNA (mRNA) in HDPCs upon inflammatory stimuli and impeded HDPC proliferation by decreasing cell number, arresting cell cycle, and increasing apoptosis. Suppressed EZH2 impaired adipogenesis, peroxisome proliferator-activated receptor r (PPAR-r), and CCAAT-enhancer binding protein a (CEBP/a) mRNA in adipogenic induction while enhancing alkaline phosphatase activity, Osx, and bone sialoprotein (BSP) mRNA in mineralization induction of HDPCs. CONCLUSIONS EZH2 inhibited HDPC osteogenic differentiation while enhancing inflammatory response and proliferation, suggesting its role in pulp inflammation, proliferation, and regeneration.
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Affiliation(s)
- Tianqian Hui
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Peng A
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Yuan Zhao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Chenglin Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Bo Gao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Ping Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Jun Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Ling Ye
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China.
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210
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Yamaguchi H, Hung MC. Regulation and Role of EZH2 in Cancer. Cancer Res Treat 2014; 46:209-22. [PMID: 25038756 PMCID: PMC4132442 DOI: 10.4143/crt.2014.46.3.209] [Citation(s) in RCA: 211] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/05/2014] [Indexed: 12/11/2022] Open
Abstract
Polycomb repressive complex 2 (PRC2) is the epigenetic regulator that induces histone H3 lysine 27 methylation (H3K27me3) and silences specific gene transcription. Enhancer of zeste homolog 2 (EZH2) is an enzymatic subunit of PRC2, and evidence shows that EZH2 plays an essential role in cancer initiation, development, progression, metastasis, and drug resistance. EZH2 expression is indeed regulated by various oncogenic transcription factors, tumor suppressor miRNAs, and cancer-associated non-coding RNA. EZH2 activity is also controlled by post-translational modifications, which are deregulated in cancer. The canonical role of EZH2 is gene silencing through H3K27me3, but accumulating evidence shows that EZH2 methlyates substrates other than histone and has methylase-independent functions. These non-canonical functions of EZH2 are shown to play a role in cancer progression. In this review, we summarize current information on the regulation and roles of EZH2 in cancer. We also discuss various therapeutic approaches to targeting EZH2.
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Affiliation(s)
- Hirohito Yamaguchi
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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211
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Anderson AE, Galko MJ. Rapid clearance of epigenetic protein reporters from wound edge cells in Drosophila larvae does not depend on the JNK or PDGFR/VEGFR signaling pathways. ACTA ACUST UNITED AC 2014; 1:11-25. [PMID: 25114797 PMCID: PMC4126263 DOI: 10.1002/reg2.12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The drastic cellular changes required for epidermal cells to dedifferentiate and become motile during wound closure are accompanied by changes in gene transcription, suggesting corresponding alterations in chromatin. However, the epigenetic changes that underlie wound-induced transcriptional programs remain poorly understood partly because a comprehensive study of epigenetic factor expression during wound healing has not been practical. To determine which chromatin modifying factors might contribute to wound healing, we screened publicly available fluorescently-tagged reporter lines in Drosophila for altered expression at the wound periphery during healing. Thirteen reporters tagging seven different proteins showed strongly diminished expression at the wound edge. Three downregulated proteins, Osa, Kismet, and Spt6, are generally associated with active chromatin, while four others, Sin3A, Sap130, Mi-2, and Mip120, are associated with repressed chromatin. In all cases reporter down regulation was independent of the Jun N-terminal Kinase and Pvr pathways, suggesting that novel signals control reporter clearance. Taken together, our results suggest that clearance of chromatin modifying factors may enable wound edge cells to rapidly and comprehensively change their transcriptional state following tissue damage.
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Affiliation(s)
- Aimee E Anderson
- Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, Unit 1000, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Michael J Galko
- Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, Unit 1000, 1515 Holcombe Boulevard, Houston, TX 77030, USA ; Genes & Development Graduate Program, The University of Texas MD Anderson Cancer Center, Unit 1000, 1515 Holcombe Boulevard, Houston, TX 77030, USA
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212
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From innate to adaptive immune response in muscular dystrophies and skeletal muscle regeneration: the role of lymphocytes. BIOMED RESEARCH INTERNATIONAL 2014; 2014:438675. [PMID: 25028653 PMCID: PMC4083765 DOI: 10.1155/2014/438675] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 05/02/2014] [Indexed: 12/04/2022]
Abstract
Skeletal muscle is able to restore contractile functionality after injury thanks to its ability to regenerate. Following muscle necrosis, debris is removed by macrophages, and muscle satellite cells (MuSCs), the muscle stem cells, are activated and subsequently proliferate, migrate, and form muscle fibers restoring muscle functionality. In most muscle dystrophies (MDs), MuSCs fail to properly proliferate, differentiate, or replenish the stem cell compartment, leading to fibrotic deposition. However, besides MuSCs, interstitial nonmyogenic cells and inflammatory cells also play a key role in orchestrating muscle repair. A complete understanding of the complexity of these mechanisms should allow the design of interventions to attenuate MDs pathology without disrupting regenerative processes. In this review we will focus on the contribution of immune cells in the onset and progression of MDs, with particular emphasis on Duchenne muscular dystrophy (DMD). We will briefly summarize the current knowledge and recent advances made in our understanding of the involvement of different innate immune cells in MDs and will move on to critically evaluate the possible role of cell populations within the acquired immune response. Revisiting previous observations in the light of recent evidence will likely change our current view of the onset and progression of the disease.
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213
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Brien P, Pugazhendhi D, Woodhouse S, Oxley D, Pell JM. p38α MAPK regulates adult muscle stem cell fate by restricting progenitor proliferation during postnatal growth and repair. Stem Cells 2014; 31:1597-610. [PMID: 23592450 DOI: 10.1002/stem.1399] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 03/05/2013] [Accepted: 03/18/2013] [Indexed: 11/05/2022]
Abstract
Stem cell function is essential for the maintenance of adult tissue homeostasis. Controlling the balance between self-renewal and differentiation is crucial to maintain a receptive satellite cell pool capable of responding to growth and regeneration cues. The mitogen-activated protein kinase p38α has been implicated in the regulation of these processes but its influence in adult muscle remains unknown. Using conditional satellite cell p38α knockout mice we have demonstrated that p38α restricts excess proliferation in the postnatal growth phase while promoting timely myoblast differentiation. Differentiation was still able to occur in the p38α-null satellite cells, however, but was delayed. An absence of p38α resulted in a postnatal growth defect along with the persistence of an increased reservoir of satellite cells into adulthood. This population was still capable of responding to cardiotoxin-induced injury, resulting in complete, albeit delayed, regeneration, with further enhancement of the satellite cell population. Increased p38γ phosphorylation accompanied the absence of p38α, and inhibition of p38γ ex vivo substantially decreased the myogenic defect. We have used genome-wide transcriptome analysis to characterize the changes in expression that occur between resting and regenerating muscle, and the influence p38α has on these expression profiles. This study provides novel evidence for the fundamental role of p38α in adult muscle homeostasis in vivo.
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214
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Garcia-Guerra L, Vila-Bedmar R, Carrasco-Rando M, Cruces-Sande M, Martín M, Ruiz-Gómez A, Ruiz-Gómez M, Lorenzo M, Fernández-Veledo S, Mayor F, Murga C, Nieto-Vázquez I. Skeletal muscle myogenesis is regulated by G protein-coupled receptor kinase 2. J Mol Cell Biol 2014; 6:299-311. [PMID: 24927997 DOI: 10.1093/jmcb/mju025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
G protein-coupled receptor kinase 2 (GRK2) is an important serine/threonine-kinase regulating different membrane receptors and intracellular proteins. Attenuation of Drosophila Gprk2 in embryos or adult flies induced a defective differentiation of somatic muscles, loss of fibers, and a flightless phenotype. In vertebrates, GRK2 hemizygous mice contained less but more hypertrophied skeletal muscle fibers than wild-type littermates. In C2C12 myoblasts, overexpression of a GRK2 kinase-deficient mutant (K220R) caused precocious differentiation of cells into immature myotubes, which were wider in size and contained more fused nuclei, while GRK2 overexpression blunted differentiation. Moreover, p38MAPK and Akt pathways were activated at an earlier stage and to a greater extent in K220R-expressing cells or upon kinase downregulation, while the activation of both kinases was impaired in GRK2-overexpressing cells. The impaired differentiation and fewer fusion events promoted by enhanced GRK2 levels were recapitulated by a p38MAPK mutant, which was able to mimic the inhibitory phosphorylation of p38MAPK by GRK2, whereas the blunted differentiation observed in GRK2-expressing clones was rescued in the presence of a constitutively active upstream stimulator of the p38MAPK pathway. These results suggest that balanced GRK2 function is necessary for a timely and complete myogenic process.
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Affiliation(s)
- Lucia Garcia-Guerra
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Complutense University, 28040 Madrid, Spain CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain CIBER de enfermedades neurodegenerativas (CIBERNED), 28049 Madrid, Spain
| | - Rocío Vila-Bedmar
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | | | - Marta Cruces-Sande
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | - Mercedes Martín
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
| | - Ana Ruiz-Gómez
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
| | - Mar Ruiz-Gómez
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
| | - Margarita Lorenzo
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Complutense University, 28040 Madrid, Spain CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain
| | - Sonia Fernández-Veledo
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain Hospital Universitari de Tarragona Joan XXIII. IISPV. Universitat Rovira i Virgili, 43007 Tarragona, Spain
| | - Federico Mayor
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | - Cristina Murga
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | - Iria Nieto-Vázquez
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Complutense University, 28040 Madrid, Spain CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain
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215
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Abstract
Given that treatment options for patients with glioblastoma are limited, much effort has been made to clarify the underlying mechanisms of gliomagenesis. Recent genome-wide genomic and epigenomic analyses have revealed that mutations in epigenetic modifiers occur frequently in gliomas and that dysregulation of epigenetic mechanisms is closely associated with glioma formation. Given that epigenetic changes are reversible, understanding the epigenetic abnormalities that arise in gliomagenesis might be key to developing more effective treatment strategies for glioma. In this review, we focus on the recent advancements in epigenetic research with respect to gliomas, consider how epigenetic mechanisms dynamically regulate tumor cells, including the cancer stem cell population, and discuss perspectives and challenges for glioma treatment in the near future.
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Affiliation(s)
- Yutaka Kondo
- Division of Epigenomics, Aichi Cancer Center Research InstituteNagoya, Japan
- Division of Molecular Oncology, Aichi Cancer Center Research InstituteNagoya, Japan
| | - Keisuke Katsushima
- Division of Epigenomics, Aichi Cancer Center Research InstituteNagoya, Japan
| | - Fumiharu Ohka
- Division of Epigenomics, Aichi Cancer Center Research InstituteNagoya, Japan
- Division of Molecular Oncology, Aichi Cancer Center Research InstituteNagoya, Japan
- Department of Neurosurgery, Nagoya University School of MedicineNagoya, Japan
| | - Atsushi Natsume
- Department of Neurosurgery, Nagoya University School of MedicineNagoya, Japan
| | - Keiko Shinjo
- Division of Epigenomics, Aichi Cancer Center Research InstituteNagoya, Japan
- Division of Molecular Pathology, Aichi Cancer Center Research InstituteNagoya, Japan
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216
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Narasimhan M, Hong J, Atieno N, Muthusamy VR, Davidson CJ, Abu-Rmaileh N, Richardson RS, Gomes AV, Hoidal JR, Rajasekaran NS. Nrf2 deficiency promotes apoptosis and impairs PAX7/MyoD expression in aging skeletal muscle cells. Free Radic Biol Med 2014; 71:402-414. [PMID: 24613379 PMCID: PMC4493911 DOI: 10.1016/j.freeradbiomed.2014.02.023] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 02/17/2014] [Accepted: 02/25/2014] [Indexed: 12/20/2022]
Abstract
Skeletal muscle redox homeostasis is transcriptionally regulated by nuclear erythroid-2-p45-related factor-2 (Nrf2). We recently demonstrated that age-associated stress impairs Nrf2-ARE (antioxidant-response element) transcriptional signaling. Here, we hypothesize that age-dependent decline or genetic ablation of Nrf2 leads to accelerated apoptosis and skeletal muscle degeneration. Under basal-physiological conditions, disruption of Nrf2 significantly downregulates antioxidants and causes oxidative stress. Surprisingly, Nrf2-null mice had enhanced antioxidant capacity identical to wild-type (WT) upon acute endurance exercise stress (AEES), suggesting activation of Nrf2-independent mechanisms (i.e., PGC1α) against oxidative stress. Analysis of prosurvival pathways in the basal state reveals decreased AKT levels, whereas p-p53, a repressor of AKT, was increased in Nrf2-null vs WT mice. Upon AEES, AKT and p-AKT levels were significantly (p < 0.001) increased (>10-fold) along with profound downregulation of p-p53 (p < 0.01) in Nrf2-null vs WT skeletal muscle, indicating the onset of prosurvival mechanisms to compensate for the loss of Nrf2 signaling. However, we found a decreased stem cell population (PAX7) and MyoD expression (differentiation) along with profound activation of ubiquitin and apoptotic pathways in Nrf2-null vs WT mice upon AEES, suggesting that compensatory prosurvival mechanisms failed to overcome the programmed cell death and degeneration in skeletal muscle. Further, the impaired regeneration was sustained in Nrf2-null vs WT mice after 1 week of post-AEES recovery. In an age-associated oxidative stress condition, ablation of Nrf2 results in induction of apoptosis and impaired muscle regeneration.
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Affiliation(s)
- Madhusudhanan Narasimhan
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Cardiac Aging and Redox Signaling Laboratory, Division of Cardiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Jennifer Hong
- Cardiac Aging and Redox Signaling Laboratory, Division of Cardiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Nancy Atieno
- Cardiac Aging and Redox Signaling Laboratory, Division of Cardiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Vasanthi R Muthusamy
- Cardiac Aging and Redox Signaling Laboratory, Division of Cardiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Christopher J Davidson
- Cardiac Aging and Redox Signaling Laboratory, Division of Cardiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Naser Abu-Rmaileh
- Cardiac Aging and Redox Signaling Laboratory, Division of Cardiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Russell S Richardson
- Division of Geriatrics, and Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; Department of Exercise & Sports Sciences, College of Health, University of Utah, Salt Lake City, UT 84112, USA; Geriatric Research, Education, and Clinical Center, Salt Lake City Veteran's Medical Center
| | | | - John R Hoidal
- Division of Pulmonary Medicine, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Namakkal S Rajasekaran
- Cardiac Aging and Redox Signaling Laboratory, Division of Cardiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; Department of Exercise & Sports Sciences, College of Health, University of Utah, Salt Lake City, UT 84112, USA.
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217
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Li YP, Niu A, Wen Y. Regulation of myogenic activation of p38 MAPK by TACE-mediated TNFα release. Front Cell Dev Biol 2014; 2:21. [PMID: 25364728 PMCID: PMC4207040 DOI: 10.3389/fcell.2014.00021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/07/2014] [Indexed: 11/24/2022] Open
Abstract
The activation of p38 MAPK in myogenic precursor cells (MPCs) is a key signal for their exit of cell cycle and entry of the myogenic differentiation program. Therefore, identification of the signaling mechanism that activates p38 MAPK during this process is important for the understanding of the regulatory mechanism of muscle regeneration. This article reviews recent findings regarding the role of inflammatory cytokine tumor necrosis factor-α (TNFα) as a key activator of p38 MAPK during myogenesis in an autocrine/paracrine fashion, and the signaling mechanisms that converge upon TNFα converting enzyme (TACE) to release TNFα from differentiating MPCs in response to diverse regenerative stimuli.
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Affiliation(s)
- Yi-Ping Li
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center Houston, TX, USA
| | - Airu Niu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center Houston, TX, USA
| | - Yefei Wen
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center Houston, TX, USA
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218
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Abstract
The intestinal stem cell fuels the highest rate of tissue turnover in the body and has been implicated in intestinal disease and cancer; understanding the regulatory mechanisms controlling intestinal stem cell physiology is of great importance. Here, we provide evidence that the transcription factor YY1 is essential for intestinal stem cell renewal. We observe that YY1 loss skews normal homeostatic cell turnover, with an increase in proliferating crypt cells and a decrease in their differentiated villous progeny. Increased crypt cell numbers come at the expense of Lgr5(+) stem cells. On YY1 deletion, Lgr5(+) cells accelerate their commitment to the differentiated population, exhibit increased levels of apoptosis, and fail to maintain stem cell renewal. Loss of Yy1 in the intestine is ultimately fatal. Mechanistically, YY1 seems to play a role in stem cell energy metabolism, with mitochondrial complex I genes bound directly by YY1 and their transcript levels decreasing on YY1 loss. These unappreciated YY1 functions broaden our understanding of metabolic regulation in intestinal stem cell homeostasis.
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219
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Tripathi AK, Patel AK, Shah RK, Patel AB, Shah TM, Bhatt VD, Joshi CG. Transcriptomic dissection of myogenic differentiation signature in caprine by RNA-Seq. Mech Dev 2014; 132:79-92. [DOI: 10.1016/j.mod.2014.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 01/01/2014] [Accepted: 01/02/2014] [Indexed: 10/25/2022]
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220
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Kolybaba A, Classen AK. Sensing cellular states--signaling to chromatin pathways targeting Polycomb and Trithorax group function. Cell Tissue Res 2014; 356:477-93. [PMID: 24728925 DOI: 10.1007/s00441-014-1824-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 01/22/2014] [Indexed: 02/06/2023]
Abstract
Cells respond to extra- and intra-cellular signals by dynamically changing their gene expression patterns. After termination of the original signal, new expression patterns are maintained by epigenetic DNA and histone modifications. This represents a powerful mechanism that enables long-term phenotypic adaptation to transient signals. Adaptation of epigenetic landscapes is important for mediating cellular differentiation during development and allows adjustment to altered environmental conditions throughout life. Work over the last decade has begun to elucidate the way that extra- and intra-cellular signals lead to changes in gene expression patterns by directly modulating the function of chromatin-associated proteins. Here, we review key signaling-to-chromatin pathways that are specifically thought to target Polycomb and Trithorax group complexes, a classic example of epigenetically acting gene silencers and activators important in development, stem cell differentiation and cancer. We discuss the influence that signals triggered by kinase cascades, metabolic fluctuations and cell-cycle dynamics have on the function of these protein complexes. Further investigation into these pathways will be important for understanding the mechanisms that maintain epigenetic stability and those that promote epigenetic plasticity.
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Affiliation(s)
- Addie Kolybaba
- Ludwig Maximilians University Munich, Faculty of Biology, Grosshaderner Strasse 2-4, 82152, Planegg-Martinsried, Germany
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221
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Inflammation-induced repression of chromatin bound by the transcription factor Foxp3 in regulatory T cells. Nat Immunol 2014; 15:580-587. [PMID: 24728351 PMCID: PMC4112080 DOI: 10.1038/ni.2868] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/10/2014] [Indexed: 12/11/2022]
Abstract
The transcription factor Foxp3 is indispensable for the ability of regulatory T (Treg) cells to suppress fatal inflammation. Here, we characterized the role of Foxp3 in chromatin remodeling and regulation of gene expression in actively suppressing Treg cells in an inflammatory setting. Although genome-wide Foxp3 occupancy of DNA regulatory elements was similar in resting and in vivo activated Treg cells, Foxp3-bound enhancers were poised for repression only in activated Treg cells. Following activation, Foxp3-bound sites showed reduced chromatin accessibility and selective H3K27 tri-methylation, which was associated with Ezh2 recruitment and downregulation of nearby gene expression. Thus, Foxp3 poises its targets for repression by facilitating formation of repressive chromatin in regulatory T cells upon their activation in response to inflammatory cues.
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222
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Li J, Ohliger J, Pei M. Significance of epigenetic landscape in cartilage regeneration from the cartilage development and pathology perspective. Stem Cells Dev 2014; 23:1178-94. [PMID: 24555773 DOI: 10.1089/scd.2014.0002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Regenerative therapies for cartilage defects have been greatly advanced by progress in both the stem cell biology and tissue engineering fields. Despite notable successes, significant barriers remain including shortage of autologous cell sources and generation of a stable chondrocyte phenotype using progenitor cells. Increasing demands for the treatment of degenerative diseases, such as osteoarthritis and rheumatoid arthritis, highlight the importance of epigenetic remodeling in cartilage regeneration. Epigenetic regulatory mechanisms, such as microRNAs, DNA methylation, and histone modifications, have been intensively studied due to their direct regulatory role on gene expression. However, a thorough understanding of the environmental factors that initiate these epigenetic events may provide greater insight into the prevention of degenerative diseases and improve the efficacy of treatments. In other words, if we could identify a specific factor from the environment and its downstream signaling events, then we could stop or retard degradation and enhance cartilage regeneration. A more operational definition of epigenetic remodeling has recently been proposed by categorizing the signals during the epigenetic process into epigenators, initiators, and maintainers. This review seeks to compile and reorganize the existing literature pertaining to epigenetic remodeling events placing emphasis on perceiving the landscape of epigenetic mechanisms during cartilage regeneration with the new operational definition, especially from the environmental factors' point of view. Progress in understanding epigenetic regulatory mechanisms could benefit cartilage regeneration and engineering on a larger scale and provide more promising therapeutic applications.
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Affiliation(s)
- Jingting Li
- 1 Stem Cell and Tissue Engineering Laboratory, Department of Orthopaedics, West Virginia University , Morgantown, West Virginia
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223
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Neguembor MV, Jothi M, Gabellini D. Long noncoding RNAs, emerging players in muscle differentiation and disease. Skelet Muscle 2014; 4:8. [PMID: 24685002 PMCID: PMC3973619 DOI: 10.1186/2044-5040-4-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/11/2014] [Indexed: 12/18/2022] Open
Abstract
The vast majority of the mammalian genome is transcribed giving rise to many different types of noncoding RNAs. Among them, long noncoding RNAs are the most numerous and functionally versatile class. Indeed, the lncRNA repertoire might be as rich as the proteome. LncRNAs have emerged as key regulators of gene expression at multiple levels. They play important roles in the regulation of development, differentiation and maintenance of cell identity and they also contribute to disease. In this review, we present recent advances in the biology of lncRNAs in muscle development and differentiation. We will also discuss the contribution of lncRNAs to muscle disease with a particular focus on Duchenne and facioscapulohumeral muscular dystrophies.
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Affiliation(s)
| | | | - Davide Gabellini
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Regenerative Medicine, Stem cells, and Gene therapy, DIBIT2, 5A3, Via Olgettina 58, 20132 Milano, Italy.
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224
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Tidball JG, Dorshkind K, Wehling-Henricks M. Shared signaling systems in myeloid cell-mediated muscle regeneration. Development 2014; 141:1184-96. [PMID: 24595286 PMCID: PMC3943178 DOI: 10.1242/dev.098285] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Much of the focus in muscle regeneration has been placed on the identification and delivery of stem cells to promote regenerative capacity. As those efforts have advanced, we have learned that complex features of the microenvironment in which regeneration occurs can determine success or failure. The immune system is an important contributor to that complexity and can determine the extent to which muscle regeneration succeeds. Immune cells of the myeloid lineage play major regulatory roles in tissue regeneration through two general, inductive mechanisms: instructive mechanisms that act directly on muscle cells; and permissive mechanisms that act indirectly to influence regeneration by modulating angiogenesis and fibrosis. In this article, recent discoveries that identify inductive actions of specific populations of myeloid cells on muscle regeneration are presented, with an emphasis on how processes in muscle and myeloid cells are co-regulated.
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Affiliation(s)
- James G. Tidball
- Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, CA 90095-1606, USA
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095-1606, USA
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095-1732, USA
| | - Kenneth Dorshkind
- Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, CA 90095-1606, USA
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095-1732, USA
| | - Michelle Wehling-Henricks
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095-1606, USA
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225
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Cosgrove BD, Gilbert PM, Porpiglia E, Mourkioti F, Lee SP, Corbel SY, Llewellyn ME, Delp SL, Blau HM. Rejuvenation of the muscle stem cell population restores strength to injured aged muscles. Nat Med 2014; 20:255-64. [PMID: 24531378 PMCID: PMC3949152 DOI: 10.1038/nm.3464] [Citation(s) in RCA: 454] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 01/11/2014] [Indexed: 02/08/2023]
Abstract
The elderly often suffer from progressive muscle weakness and regenerative failure. We demonstrate that muscle regeneration is impaired with aging owing in part to a cell-autonomous functional decline in skeletal muscle stem cells (MuSCs). Two-thirds of MuSCs from aged mice are intrinsically defective relative to MuSCs from young mice, with reduced capacity to repair myofibers and repopulate the stem cell reservoir in vivo following transplantation. This deficiency is correlated with a higher incidence of cells that express senescence markers and is due to elevated activity of the p38α and p38β mitogen-activated kinase pathway. We show that these limitations cannot be overcome by transplantation into the microenvironment of young recipient muscles. In contrast, subjecting the MuSC population from aged mice to transient inhibition of p38α and p38β in conjunction with culture on soft hydrogel substrates rapidly expands the residual functional MuSC population from aged mice, rejuvenating its potential for regeneration and serial transplantation as well as strengthening of damaged muscles of aged mice. These findings reveal a synergy between biophysical and biochemical cues that provides a paradigm for a localized autologous muscle stem cell therapy for the elderly.
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Affiliation(s)
- Benjamin D. Cosgrove
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Penney M. Gilbert
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Institute of Biomaterials and Biomedical Engineering and Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Ermelinda Porpiglia
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Foteini Mourkioti
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Steven P. Lee
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Bioengineering, Stanford University School of Medicine, CA, USA
| | - Stephane Y. Corbel
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Scott L. Delp
- Department of Bioengineering, Stanford University School of Medicine, CA, USA
- Department of Mechanical Engineering, Stanford University School of Medicine, CA, USA
| | - Helen M. Blau
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
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226
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Ciarapica R, Carcarino E, Adesso L, De Salvo M, Bracaglia G, Leoncini PP, Dall'agnese A, Verginelli F, Milano GM, Boldrini R, Inserra A, Stifani S, Screpanti I, Marquez VE, Valente S, Mai A, Puri PL, Locatelli F, Palacios D, Rota R. Pharmacological inhibition of EZH2 as a promising differentiation therapy in embryonal RMS. BMC Cancer 2014; 14:139. [PMID: 24575771 PMCID: PMC4016511 DOI: 10.1186/1471-2407-14-139] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 02/12/2014] [Indexed: 12/31/2022] Open
Abstract
Background Embryonal Rhabdomyosarcoma (RMS) is a pediatric soft-tissue sarcoma derived from myogenic precursors that is characterized by a good prognosis in patients with localized disease. Conversely, metastatic tumors often relapse, leading to a dismal outcome. The histone methyltransferase EZH2 epigenetically suppresses skeletal muscle differentiation by repressing the transcription of myogenic genes. Moreover, de-regulated EZH2 expression has been extensively implied in human cancers. We have previously shown that EZH2 is aberrantly over-expressed in RMS primary tumors and cell lines. Moreover, it has been recently reported that EZH2 silencing in RD cells, a recurrence-derived embryonal RMS cell line, favors myofiber-like structures formation in a pro-differentiation context. Here we evaluate whether similar effects can be obtained also in the presence of growth factor-supplemented medium (GM), that mimics a pro-proliferative microenvironment, and by pharmacological targeting of EZH2 in RD cells and in RD tumor xenografts. Methods Embryonal RMS RD cells were cultured in GM and silenced for EZH2 or treated with either the S-adenosylhomocysteine hydrolase inhibitor 3-deazaneplanocin A (DZNep) that induces EZH2 degradation, or with a new class of catalytic EZH2 inhibitors, MC1948 and MC1945, which block the catalytic activity of EZH2. RD cell proliferation and myogenic differentiation were evaluated both in vitro and in vivo. Results Here we show that EZH2 protein was abnormally expressed in 19 out of 19 (100%) embryonal RMS primary tumors and cell lines compared to their normal counterparts. Genetic down-regulation of EZH2 by silencing in GM condition reduced RD cell proliferation up-regulating p21Cip1. It also resulted in myogenic-like differentiation testified by the up-regulation of myogenic markers Myogenin, MCK and MHC. These effects were reverted by enforced over-expression of a murine Ezh2, highlighting an EZH2-specific effect. Pharmacological inhibition of EZH2 using either DZNep or MC inhibitors phenocopied the genetic knockdown of EZH2 preventing cell proliferation and restoring myogenic differentiation both in vitro and in vivo. Conclusions These results provide evidence that EZH2 function can be counteracted by pharmacological inhibition in embryonal RMS blocking proliferation even in a pro-proliferative context. They also suggest that this approach could be exploited as a differentiation therapy in adjuvant therapeutic intervention for embryonal RMS.
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Affiliation(s)
- Roberta Ciarapica
- Department of Oncohematology, Laboratory of Angiogenesis, Ospedale Pediatrico Bambino Gesù, IRCCS, Piazza S, Onofrio 4, 00165 Rome, Italy.
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He WA, Berardi E, Cardillo VM, Acharyya S, Aulino P, Thomas-Ahner J, Wang J, Bloomston M, Muscarella P, Nau P, Shah N, Butchbach MER, Ladner K, Adamo S, Rudnicki MA, Keller C, Coletti D, Montanaro F, Guttridge DC. NF-κB-mediated Pax7 dysregulation in the muscle microenvironment promotes cancer cachexia. J Clin Invest 2014; 123:4821-35. [PMID: 24084740 DOI: 10.1172/jci68523] [Citation(s) in RCA: 253] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 08/06/2013] [Indexed: 01/09/2023] Open
Abstract
Cachexia is a debilitating condition characterized by extreme skeletal muscle wasting that contributes significantly to morbidity and mortality. Efforts to elucidate the underlying mechanisms of muscle loss have predominantly focused on events intrinsic to the myofiber. In contrast, less regard has been given to potential contributory factors outside the fiber within the muscle microenvironment. In tumor-bearing mice and patients with pancreatic cancer, we found that cachexia was associated with a type of muscle damage resulting in activation of both satellite and nonsatellite muscle progenitor cells. These muscle progenitors committed to a myogenic program, but were inhibited from completing differentiation by an event linked with persistent expression of the self-renewing factor Pax7. Overexpression of Pax7 was sufficient to induce atrophy in normal muscle, while under tumor conditions, the reduction of Pax7 or exogenous addition of its downstream target, MyoD, reversed wasting by restoring cell differentiation and fusion with injured fibers. Furthermore, Pax7 was induced by serum factors from cachectic mice and patients, in an NF-κB-dependent manner, both in vitro and in vivo. Together, these results suggest that Pax7 responds to NF-κB by impairing the regenerative capacity of myogenic cells in the muscle microenvironment to drive muscle wasting in cancer.
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Animals
- Cachexia/etiology
- Cachexia/metabolism
- Cachexia/pathology
- Case-Control Studies
- Cell Line, Tumor
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Male
- Mice
- Mice, Inbred mdx
- Mice, Nude
- Mice, Transgenic
- Microscopy, Electron, Transmission
- Middle Aged
- Muscle Development
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myoblasts, Skeletal/metabolism
- Myoblasts, Skeletal/pathology
- NF-kappa B/metabolism
- PAX7 Transcription Factor/genetics
- PAX7 Transcription Factor/metabolism
- Pancreatic Neoplasms/complications
- Pancreatic Neoplasms/metabolism
- Satellite Cells, Skeletal Muscle/metabolism
- Satellite Cells, Skeletal Muscle/pathology
- Tumor Microenvironment
- Young Adult
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228
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Costamagna D, Quattrocelli M, Duelen R, Sahakyan V, Perini I, Palazzolo G, Sampaolesi M. Fate choice of post-natal mesoderm progenitors: skeletal versus cardiac muscle plasticity. Cell Mol Life Sci 2014; 71:615-27. [PMID: 23949444 PMCID: PMC11113798 DOI: 10.1007/s00018-013-1445-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 07/29/2013] [Accepted: 07/29/2013] [Indexed: 01/01/2023]
Abstract
Regenerative medicine for skeletal and cardiac muscles still constitutes a fascinating and ambitious frontier. In this perspective, understanding the possibilities of intrinsic cell plasticity, present in post-natal muscles, is vital to define and improve novel therapeutic strategies for acute and chronic diseases. In addition, many somatic stem cells are now crossing the boundaries of basic/translational research to enter the first clinical trials. However, it is still an open question whether a lineage switch between skeletal and cardiac adult myogenesis is possible. Therefore, this review focuses on resident somatic stem cells of post-natal skeletal and cardiac muscles and their plastic potential toward the two lineages. Furthermore, examples of myogenic lineage switch in adult stem cells are also reported and discussed.
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Affiliation(s)
- Domiziana Costamagna
- Translational Cardiomyology Lab, Department of Development and Regeneration, Stem Cell Institute Leuven, Embryo and Stem Cell Biology, KU Leuven, Herestraat 49, O&N4, Bus 814, 3000 Leuven, Belgium
| | - Mattia Quattrocelli
- Translational Cardiomyology Lab, Department of Development and Regeneration, Stem Cell Institute Leuven, Embryo and Stem Cell Biology, KU Leuven, Herestraat 49, O&N4, Bus 814, 3000 Leuven, Belgium
| | - Robin Duelen
- Translational Cardiomyology Lab, Department of Development and Regeneration, Stem Cell Institute Leuven, Embryo and Stem Cell Biology, KU Leuven, Herestraat 49, O&N4, Bus 814, 3000 Leuven, Belgium
| | - Vardine Sahakyan
- Translational Cardiomyology Lab, Department of Development and Regeneration, Stem Cell Institute Leuven, Embryo and Stem Cell Biology, KU Leuven, Herestraat 49, O&N4, Bus 814, 3000 Leuven, Belgium
| | - Ilaria Perini
- Translational Cardiomyology Lab, Department of Development and Regeneration, Stem Cell Institute Leuven, Embryo and Stem Cell Biology, KU Leuven, Herestraat 49, O&N4, Bus 814, 3000 Leuven, Belgium
| | - Giacomo Palazzolo
- Translational Cardiomyology Lab, Department of Development and Regeneration, Stem Cell Institute Leuven, Embryo and Stem Cell Biology, KU Leuven, Herestraat 49, O&N4, Bus 814, 3000 Leuven, Belgium
| | - Maurilio Sampaolesi
- Translational Cardiomyology Lab, Department of Development and Regeneration, Stem Cell Institute Leuven, Embryo and Stem Cell Biology, KU Leuven, Herestraat 49, O&N4, Bus 814, 3000 Leuven, Belgium
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229
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Marchesi I, Giordano A, Bagella L. Roles of enhancer of zeste homolog 2: from skeletal muscle differentiation to rhabdomyosarcoma carcinogenesis. Cell Cycle 2014; 13:516-27. [PMID: 24496329 DOI: 10.4161/cc.27921] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Polycomb group proteins represent a global silencing system involved in embryonic development and stem-cell maintenance that regulates the transition from proliferation to differentiation during organogenesis. Two main complexes have been discovered: the polycomb repressive complex (PRC) 1 and 2, able to induce gene silencing by a synergistic mechanism or independently by each other. Enhancer of zeste homolog 2 (EZH2), the catalytic subunit of PRC2, represses gene transcription through the tri-methylation of histone H3 lysine 27. EZH2 deregulation is frequently associated with tumorigenesis, metastatic character, and poor prognosis in various cancer types. This review explores the role of EZH2 in normal development and in carcinogenesis. We reviewed the polycomb-mediated silencing mechanisms, the regulation of EZH2 activity and its recruitment to target genes. We also analyzed the role of EZH2 in normal muscle differentiation and in rhabdomyosarcoma, considering EZH2 blockade as a new strategy for developing specific therapies.
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Affiliation(s)
- Irene Marchesi
- Department of Biomedical Sciences; Division of Biochemistry and National Institute of Biostructures and Biosystems; University of Sassari; Sassari, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine; Center for Biotechnology; College of Science and Technology; Temple University; Philadelphia, PA USA; Human Pathology and Oncology Department; University of Siena; Siena, Italy
| | - Luigi Bagella
- Department of Biomedical Sciences; Division of Biochemistry and National Institute of Biostructures and Biosystems; University of Sassari; Sassari, Italy; Sbarro Institute for Cancer Research and Molecular Medicine; Center for Biotechnology; College of Science and Technology; Temple University; Philadelphia, PA USA
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230
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Mozzetta C, Pontis J, Fritsch L, Robin P, Portoso M, Proux C, Margueron R, Ait-Si-Ali S. The histone H3 lysine 9 methyltransferases G9a and GLP regulate polycomb repressive complex 2-mediated gene silencing. Mol Cell 2014; 53:277-89. [PMID: 24389103 DOI: 10.1016/j.molcel.2013.12.005] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 08/12/2013] [Accepted: 11/26/2013] [Indexed: 12/13/2022]
Abstract
G9a/GLP and Polycomb Repressive Complex 2 (PRC2) are two major epigenetic silencing machineries, which in particular methylate histone H3 on lysines 9 and 27 (H3K9 and H3K27), respectively. Although evidence of a crosstalk between H3K9 and H3K27 methylations has started to emerge, their actual interplay remains elusive. Here, we show that PRC2 and G9a/GLP interact physically and functionally. Moreover, combining different genome-wide approaches, we demonstrate that Ezh2 and G9a/GLP share an important number of common genomic targets, encoding developmental and neuronal regulators. Furthermore, we show that G9a enzymatic activity modulates PRC2 genomic recruitment to a subset of its target genes. Taken together, our findings demonstrate an unanticipated interplay between two main histone lysine methylation mechanisms, which cooperate to maintain silencing of a subset of developmental genes.
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Affiliation(s)
- Chiara Mozzetta
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Epigénétique et Destin Cellulaire, UMR7216, Centre National de la Recherche Scientifique CNRS, 35 rue Hélène Brion, 75013 Paris, France.
| | - Julien Pontis
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Epigénétique et Destin Cellulaire, UMR7216, Centre National de la Recherche Scientifique CNRS, 35 rue Hélène Brion, 75013 Paris, France
| | - Lauriane Fritsch
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Epigénétique et Destin Cellulaire, UMR7216, Centre National de la Recherche Scientifique CNRS, 35 rue Hélène Brion, 75013 Paris, France
| | - Philippe Robin
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Epigénétique et Destin Cellulaire, UMR7216, Centre National de la Recherche Scientifique CNRS, 35 rue Hélène Brion, 75013 Paris, France
| | - Manuela Portoso
- Institut Curie, 26 rue d'Ulm, 75005 Paris, France; UMR3215 CNRS, 26 rue d'Ulm, 75005 Paris, France; U934 INSERM, 26 rue d'Ulm, 75005 Paris, France
| | - Caroline Proux
- Institut Pasteur, PF2 Plate-forme Transcriptome et Epigénome, 28 rue du Dr Roux, Paris, 75015 France
| | - Raphaël Margueron
- Institut Curie, 26 rue d'Ulm, 75005 Paris, France; UMR3215 CNRS, 26 rue d'Ulm, 75005 Paris, France; U934 INSERM, 26 rue d'Ulm, 75005 Paris, France
| | - Slimane Ait-Si-Ali
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Epigénétique et Destin Cellulaire, UMR7216, Centre National de la Recherche Scientifique CNRS, 35 rue Hélène Brion, 75013 Paris, France.
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231
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232
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Toffolo E, Rusconi F, Paganini L, Tortorici M, Pilotto S, Heise C, Verpelli C, Tedeschi G, Maffioli E, Sala C, Mattevi A, Battaglioli E. Phosphorylation of neuronal Lysine-Specific Demethylase 1LSD1/KDM1A impairs transcriptional repression by regulating interaction with CoREST and histone deacetylases HDAC1/2. J Neurochem 2013; 128:603-16. [PMID: 24111946 DOI: 10.1111/jnc.12457] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/10/2013] [Accepted: 09/16/2013] [Indexed: 01/31/2023]
Abstract
Epigenetic mechanisms play important roles in brain development, orchestrating proliferation, differentiation, and morphogenesis. Lysine-Specific Demethylase 1 (LSD1 also known as KDM1A and AOF2) is a histone modifier involved in transcriptional repression, forming a stable core complex with the corepressors corepressor of REST (CoREST) and histone deacetylases (HDAC1/2). Importantly, in the mammalian CNS, neuronal LSD1-8a, an alternative splicing isoform of LSD1 including the mini-exon E8a, sets alongside LSD1 and is capable of enhancing neurite growth and morphogenesis. Here, we describe that the morphogenic properties of neuronal LSD1-8a require switching off repressive activity and this negative modulation is mediated in vivo by phosphorylation of the Thr369b residue coded by exon E8a. Three-dimensional crystal structure analysis using a phospho-mimetic mutant (Thr369bAsp), indicate that phosphorylation affects the residues surrounding the exon E8a-coded amino acids, causing a local conformational change. We suggest that phosphorylation, without affecting demethylase activity, causes in neurons CoREST and HDAC1/2 corepressors detachment from LSD1-8a and impairs neuronal LSD1-8a repressive activity. In neurons, Thr369b phosphorylation is required for morphogenic activity, converting neuronal LSD1-8a in a dominant-negative isoform, challenging LSD1-mediated transcriptional repression on target genes.
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Affiliation(s)
- Emanuela Toffolo
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
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233
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Herz HM, Garruss A, Shilatifard A. SET for life: biochemical activities and biological functions of SET domain-containing proteins. Trends Biochem Sci 2013; 38:621-39. [PMID: 24148750 DOI: 10.1016/j.tibs.2013.09.004] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 09/06/2013] [Accepted: 09/12/2013] [Indexed: 01/23/2023]
Affiliation(s)
- Hans-Martin Herz
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
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234
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Turgeon N, Blais M, Delabre JF, Asselin C. The histone H3K27 methylation mark regulates intestinal epithelial cell density-dependent proliferation and the inflammatory response. J Cell Biochem 2013. [PMID: 23192652 PMCID: PMC3617464 DOI: 10.1002/jcb.24463] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Polycomb-group proteins form multimeric protein complexes involved in transcriptional silencing. The Polycomb Repressive complex 2 (PRC2) contains the Suppressor of Zeste-12 protein (Suz12) and the histone methyltransferase Enhancer of Zeste protein-2 (Ezh2). This complex, catalyzing the di- and tri-methylation of histone H3 lysine 27, is essential for embryonic development and stem cell renewal. However, the role of Polycomb-group protein complexes in the control of the intestinal epithelial cell (IEC) phenotype is not known. We show that Suz12 and Ezh2 were differentially expressed along the intestinal crypt-villus axis. ShRNA-mediated Suz12 depletion in the IEC-6 rat crypt-derived cell line decreased Ezh2 expression and H3K27 di-trimethylation. Suz12-depleted cells achieved higher cell densities after confluence, with increased cyclin D2 and cyclin D3 protein levels, and increased STAT3 activation in post-confluent cells. Suz12 depletion specifically increased mostly developmental, cell adhesion and immune response gene expression, including neuronal and inflammatory genes. Suz12 depletion directly and indirectly de-regulated the IL-1β-dependent inflammatory response, as demonstrated by decreased MAPK p38 activation as opposed to JNK activation, and altered basal and stimulated expression of inflammatory genes, including transcription factors such as C/EBPβ. Of note, this positive effect on cell proliferation and inflammatory gene expression was revealed in the absence of the cyclin-dependent kinase inhibitor p16, a main target negatively regulated by PRC2. These results demonstrate that the PRC2 complex, in addition to keeping in check non-IEC differentiation pathways, insures the proper IEC response to cell density as well as to external growth and inflammatory signals, by controlling specific signaling pathways. J. Cell. Biochem. 114: 1203–1215, 2013. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
| | | | | | - Claude Asselin
- *Correspondence to: Claude Asselin, PhD, Faculté de médecine et des sciences de la santé, Département d'anatomie et biologie cellulaire, Université de Sherbrooke, Sherbrooke, Québec, Canada J1E 4K8. E-mail:
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235
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Genome-wide survey by ChIP-seq reveals YY1 regulation of lincRNAs in skeletal myogenesis. EMBO J 2013; 32:2575-88. [PMID: 23942234 DOI: 10.1038/emboj.2013.182] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 07/09/2013] [Indexed: 11/09/2022] Open
Abstract
Skeletal muscle differentiation is orchestrated by a network of transcription factors, epigenetic regulators, and non-coding RNAs. The transcription factor Yin Yang 1 (YY1) silences multiple target genes in myoblasts (MBs) by recruiting Ezh2 (Enhancer of Zeste Homologue2). To elucidate genome-wide YY1 binding in MBs, we performed chromatin immunoprecipitation (ChIP)-seq and found 1820 specific binding sites in MBs with a large portion residing in intergenic regions. Detailed analysis demonstrated that YY1 acts as an activator for many loci in addition to its known repressor function. No significant co-occupancy was found between YY1 and Ezh2, suggesting an additional Ezh2-independent function for YY1 in MBs. Further analysis of intergenic binding sites showed that YY1 potentially regulates dozens of large intergenic non-coding RNAs (lincRNAs), whose function in myogenesis is underexplored. We characterized a novel muscle-associated lincRNA (Yam-1) that is positively regulated by YY1. Yam-1 is downregulated upon differentiation and acts as an inhibitor of myogenesis. We demonstrated that Yam-1 functions through in cis regulation of miR-715, which in turn targets Wnt7b. Our findings not only provide the first genome-wide picture of YY1 association in muscle cells, but also uncover the functional role of lincRNA Yam-1.
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236
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Chen S, Sheng C, Liu D, Yao C, Gao S, Song L, Jiang W, Li J, Huang W. Enhancer of zeste homolog 2 is a negative regulator of mitochondria-mediated innate immune responses. THE JOURNAL OF IMMUNOLOGY 2013; 191:2614-23. [PMID: 23918984 DOI: 10.4049/jimmunol.1203143] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The intracellular RIG-I-like receptors recognize 5'-triphosphate viral genomic RNA and initiate the production of cytokines through mitochondria adaptor VISA. The regulation of this signal pathway is largely unknown. In this study, we report that the histone methyltransferase enhancer of zeste homolog 2 (EZH2) inhibits RIG-I signal pathway in an methyltransferase-independent manner. Knockdown EZH2 expression enhances VISA-induced activation of IFN-β promoter and NF-κB signaling. Cytosolic distributed EZH2 colocalizes with VISA and binds to its caspase recruitment domain (CARD), thus blocking its association with RIG-I. During the infection of influenza A virus (IAV) strain A/WSN/33 (WSN), EZH2 translocates to RIG-I and continuously interferes the interaction between RIG-I and VISA. Both N and C termini of EZH2 interact with VISA and attenuate its downstream signaling. WSN virus infection-induced expression of TNF-α, IFN-β, and IL-8 is inhibited by EZH2 and its catalytic dead form ΔSET. EZH2 overexpression facilitates the replications of IAV strains WSN and A/Puerto Rico/8/34 influenza virus. Knockdown EZH2 expression activates infection-induced IFN-β transcription and inhibits virus replication. We further provided evidence to show that pharmacological disruption of EZH2 expression by its inhibitor 3-deazaneplanocin A activates innate immune responses and attenuates the replication of WSN virus in HeLa, MDCK, and mouse primary bone marrow-derived macrophages, but not in IFN-deficient Vero cells. Collectively, these results revealed that EZH2 binds to VISA and interferes with the interaction between VISA and RIG-I. Targeting EZH2 activates mitochondria-mediated antiviral innate immune responses, and thus represses the replication of IAV in cells.
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Affiliation(s)
- Shuai Chen
- Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
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237
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Keller C, Guttridge DC. Mechanisms of impaired differentiation in rhabdomyosarcoma. FEBS J 2013; 280:4323-34. [PMID: 23822136 DOI: 10.1111/febs.12421] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/17/2013] [Accepted: 07/01/2013] [Indexed: 12/22/2022]
Abstract
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood, with presumed skeletal muscle origins, because of its myogenic phenotype. RMS is composed of two main subtypes, embryonal RMS (eRMS) and alveolar RMS (aRMS). Whereas eRMS histologically resembles embryonic skeletal muscle, the aRMS subtype is more aggressive and has a poorer prognosis. In addition, whereas the genetic profile of eRMS is not well established, aRMS is commonly associated with distinct chromosome translocations that fuse domains of the transcription factors Pax3 and Pax7 to the forkhead family member FOXO1A. Both eRMS and aRMS tumor cells express myogenic markers such as MyoD, but their ability to complete differentiation is impaired. How this impairment occurs is the subject of this review, which will focus on several themes, including signaling pathways that converge on Pax-forkhead gene targets, alterations in MyoD function, epigenetic modifications of myogenic promoters, and microRNAs whose expression patterns in RMS alter key regulatory circuits to help maintain tumor cells in an opportunistically less differentiated state.
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Affiliation(s)
- Charles Keller
- Pediatric Cancer Biology Program, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
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238
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Niu A, Wen Y, Liu H, Zhan M, Jin B, Li YP. Src mediates the mechanical activation of myogenesis by activating TNFα-converting enzyme. J Cell Sci 2013; 126:4349-57. [PMID: 23868980 DOI: 10.1242/jcs.125328] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mechanical stimulation affects many biological aspects in living cells through mechanotransduction. In myogenic precursor cells (MPCs), mechanical stimulation activates p38 mitogen-activated protein kinase (MAPK), a key regulator of myogenesis, via activating TNFα-converting enzyme (TACE, also known as ADAM17), to release autocrine TNFα. However, the signaling mechanism of mechanical activation of TACE is unknown. Because TACE possesses the structural features of substrates of the non-receptor tyrosine kinase Src, we tested the hypothesis that Src mediates mechanical activation of TACE in MPCs. We observed that mechanical stretch of C2C12 or primary rat myoblasts rapidly activates Src, which in turn interacts and colocalizes with TACE, resulting in tyrosine phosphorylation and activation of TACE. Particularly, Src activates TACE via the phosphorylation of amino acid residue Tyr702 in the intracellular tail of TACE, resulting in increased TNFα release and p38 activation. Src inhibition or deficiency blocks stretch activation of the TACE-p38-MAPK signaling, resulting in impaired myogenic gene expression. In response to functional overloading, Src and TACE are activated in mouse soleus muscle. Further, overloading-induced myogenesis and regeneration are impaired in the soleus of Src(+/-) mice. Therefore, Src mediates mechano-activation of TACE and myogenesis.
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Affiliation(s)
- Airu Niu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030, USA
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239
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Giordani L, Puri PL. Epigenetic control of skeletal muscle regeneration: Integrating genetic determinants and environmental changes. FEBS J 2013; 280:4014-25. [PMID: 23745685 DOI: 10.1111/febs.12383] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 06/04/2013] [Accepted: 06/06/2013] [Indexed: 12/13/2022]
Abstract
During embryonic development, pluripotent cells are genetically committed to specific lineages by the expression of cell-type-specific transcriptional activators that direct the formation of specialized tissues and organs in response to developmental cues. Chromatin-modifying proteins are emerging as essential components of the epigenetic machinery, which establishes the nuclear landscape that ultimately determines the final identity and functional specialization of adult cells. Recent evidence has revealed that discrete populations of adult cells can retain the ability to adopt alternative cell fates in response to environmental cues. These cells include conventional adult stem cells and a still poorly defined collection of cell types endowed with facultative phenotype and functional plasticity. Under physiological conditions or adaptive states, these cells cooperate to support tissue and organ homeostasis, and to promote growth or compensatory regeneration. However, during chronic diseases and aging these cells can adopt a pathological phenotype and mediate maladaptive responses, such as the formation of fibrotic scars and fat deposition that progressively replaces structural and functional units of tissues and organs. The molecular determinants of these phenotypic transitions are only emerging from recent studies that reveal how dynamic chromatin states can generate flexible epigenetic landscapes, which confer on cells the ability to retain partial pluripotency and adapt to environmental changes. This review summarizes our current knowledge on the role of the epigenetic machinery as a 'filter' between genetic commitment and environmental signals in cell types that can alternatively promote skeletal muscle regeneration or fibro-adipogenic degeneration.
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Affiliation(s)
- Lorenzo Giordani
- Sanford-Burnham Medical Research Institute, Sanford Children's Health Research Center, La Jolla, CA, USA
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240
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Natsume A, Ito M, Katsushima K, Ohka F, Hatanaka A, Shinjo K, Sato S, Takahashi S, Ishikawa Y, Takeuchi I, Shimogawa H, Uesugi M, Okano H, Kim SU, Wakabayashi T, Issa JPJ, Sekido Y, Kondo Y. Chromatin regulator PRC2 is a key regulator of epigenetic plasticity in glioblastoma. Cancer Res 2013; 73:4559-70. [PMID: 23720055 DOI: 10.1158/0008-5472.can-13-0109] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tumor cell plasticity contributes to functional and morphologic heterogeneity. To uncover the underlying mechanisms of this plasticity, we examined glioma stem-like cells (GSC) where we found that the biologic interconversion between GSCs and differentiated non-GSCs is functionally plastic and accompanied by gain or loss of polycomb repressive complex 2 (PRC2), a complex that modifies chromatin structure. PRC2 mediates lysine 27 trimethylation on histone H3 and in GSC it affected pluripotency or development-associated genes (e.g., Nanog, Wnt1, and BMP5) together with alterations in the subcellular localization of EZH2, a catalytic component of PRC2. Intriguingly, exogenous expression of EZH2-dNLS, which lacks nuclear localization sequence, impaired the repression of Nanog expression under differentiation conditions. RNA interference (RNAi)-mediated attenuation or pharmacologic inhibition of EZH2 had little to no effect on apoptosis or bromodeoxyuridine incorporation in GSCs, but it disrupted morphologic interconversion and impaired GSC integration into the brain tissue, thereby improving survival of GSC-bearing mice. Pathologic analysis of human glioma specimens revealed that the number of tumor cells with nuclear EZH2 is larger around tumor vessels and the invasive front, suggesting that nuclear EZH2 may help reprogram tumor cells in close proximity to this microenvironment. Our results indicate that epigenetic regulation by PRC2 is a key mediator of tumor cell plasticity, which is required for the adaptation of glioblastoma cells to their microenvironment. Thus, PRC2-targeted therapy may reduce tumor cell plasticity and tumor heterogeneity, offering a new paradigm for glioma treatment.
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Affiliation(s)
- Atsushi Natsume
- Department of Neurosurgery, Nagoya University School of Medicine, Divisions of Epigenomics and Molecular Oncology, Aichi Cancer Center Research Institute
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241
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Emerging roles for chromatin as a signal integration and storage platform. Nat Rev Mol Cell Biol 2013; 14:211-24. [PMID: 23524488 DOI: 10.1038/nrm3545] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cells of a multicellular organism, all containing nearly identical genetic information, respond to differentiation cues in variable ways. In addition, cells are plastic, able to execute their specialized function while maintaining the ability to adapt to environmental changes. This is achieved through multiple mechanisms, including the direct regulation of chromatin-based processes in response to stimuli. How signal transduction pathways directly communicate with chromatin to change the epigenetic landscape is poorly understood. The preponderance of covalent modifications on histone tails coupled with a relatively small number of functional outputs raises the possibility that chromatin acts as a site of signal integration and storage.
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242
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Modak R, Basha J, Bharathy N, Maity K, Mizar P, Bhat AV, Vasudevan M, Rao VK, Kok WK, Natesh N, Taneja R, Kundu TK. Probing p300/CBP associated factor (PCAF)-dependent pathways with a small molecule inhibitor. ACS Chem Biol 2013; 8:1311-23. [PMID: 23570531 DOI: 10.1021/cb4000597] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PCAF (KAT2B) belongs to the GNAT family of lysine acetyltransferases (KAT) and specifically acetylates the histone H3K9 residue and several nonhistone proteins. PCAF is also a transcriptional coactivator. Due to the lack of a PCAF KAT-specific small molecule inhibitor, the exclusive role of the acetyltransferase activity of PCAF is not well understood. Here, we report that a natural compound of the hydroxybenzoquinone class, embelin, specifically inhibits H3Lys9 acetylation in mice and inhibits recombinant PCAF-mediated acetylation with near complete specificity in vitro. Furthermore, using embelin, we have identified the gene networks that are regulated by PCAF during muscle differentiation, further highlighting the broader regulatory functions of PCAF in muscle differentiation in addition to the regulation via MyoD acetylation.
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Affiliation(s)
- Rahul Modak
- Transcription
and Disease Laboratory,
Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore,
India 560064
| | - Jeelan Basha
- Transcription
and Disease Laboratory,
Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore,
India 560064
| | - Narendra Bharathy
- Department
of Physiology, Yong
Loo Lin School of Medicine, Block MD9, 2 Medical Drive, National University of Singapore, Singapore 117597
| | - Koustav Maity
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India 560012
| | - Pushpak Mizar
- Transcription
and Disease Laboratory,
Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore,
India 560064
| | - Akshay V. Bhat
- Transcription
and Disease Laboratory,
Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore,
India 560064
| | - Madavan Vasudevan
- Bionivid Technology [P] Ltd, 401 - 4 AB Cross, 1st Main, Kasturi Nagar,
East of NGEF, Bangalore, India 560043
| | - Vinay Kumar Rao
- Department
of Physiology, Yong
Loo Lin School of Medicine, Block MD9, 2 Medical Drive, National University of Singapore, Singapore 117597
| | - Wai Kay Kok
- Department
of Physiology, Yong
Loo Lin School of Medicine, Block MD9, 2 Medical Drive, National University of Singapore, Singapore 117597
| | - Nagashayana Natesh
- Central Government Health Scheme
Dispensary Number 3, Basavanagudi, Bangalore, India
| | - Reshma Taneja
- Department
of Physiology, Yong
Loo Lin School of Medicine, Block MD9, 2 Medical Drive, National University of Singapore, Singapore 117597
| | - Tapas K. Kundu
- Transcription
and Disease Laboratory,
Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore,
India 560064
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Amirouche A, Tadesse H, Lunde JA, Bélanger G, Côté J, Jasmin BJ. Activation of p38 signaling increases utrophin A expression in skeletal muscle via the RNA-binding protein KSRP and inhibition of AU-rich element-mediated mRNA decay: implications for novel DMD therapeutics. Hum Mol Genet 2013; 22:3093-111. [PMID: 23575223 DOI: 10.1093/hmg/ddt165] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Several therapeutic approaches are currently being developed for Duchenne muscular dystrophy (DMD) including upregulating the levels of endogenous utrophin A in dystrophic fibers. Here, we examined the role of post-transcriptional mechanisms in controlling utrophin A expression in skeletal muscle. We show that activation of p38 leads to an increase in utrophin A independently of a transcriptional induction. Rather, p38 controls the levels of utrophin A mRNA by extending the half-life of transcripts via AU-rich elements (AREs). This mechanism critically depends on a decrease in the functional availability of KSRP, an RNA-binding protein known to promote decay of ARE-containing transcripts. In vitro and in vivo binding studies revealed that KSRP interacts with specific AREs located within the utrophin A 3' UTR. Electroporation experiments to knockdown KSRP led to an increase in utrophin A in wild-type and mdx mouse muscles. In pre-clinical studies, treatment of mdx mice with heparin, an activator of p38, causes a pronounced increase in utrophin A in diaphragm muscle fibers. Together, these studies identify a pathway that culminates in the post-transcriptional regulation of utrophin A through increases in mRNA stability. Furthermore, our results constitute proof-of-principle showing that pharmacological activation of p38 may prove beneficial as a novel therapeutic approach for DMD.
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Affiliation(s)
- Adel Amirouche
- Faculty of Medicine, Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, University of Ottawa, ON, Canada K1H 8M5
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244
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Li H, Zhang R. Role of EZH2 in Epithelial Ovarian Cancer: From Biological Insights to Therapeutic Target. Front Oncol 2013; 3:47. [PMID: 23494175 PMCID: PMC3595978 DOI: 10.3389/fonc.2013.00047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 02/23/2013] [Indexed: 01/27/2023] Open
Abstract
EZH2 is the catalytic subunit of polycomb repressive complex 2 (PRC2), which generates a methylation epigenetic mark at lysine 27 residue of histone H3 (H3K27me3) to silence gene expression. EZH2 target genes are involved in a variety of biological processes such as stem cell pluripotency, cell proliferation, and oncogenic transformation. EZH2 is often over-expressed in epithelial ovarian cancer (EOC) cells and in ovarian cancer-associated stromal endothelial cells. Notably, EZH2 promotes cell proliferation, inhibits apoptosis and enhances angiogenesis in EOCs. In contrast to genetic alterations, which are typically non-reversible, epigenetic alterations are reversible. Thus, inhibiting EZH2/PRC2 activity represents an attractive strategy for developing ovarian cancer therapeutics by targeting both ovarian cancer cells and ovarian tumor microenvironment. Here we discuss the progress recently obtained in understanding how EZH2/PRC2 promotes malignant phenotypes of EOC. In addition, we focus on strategies for targeting EZH2/PRC2 to develop novel EOC epigenetic therapeutics.
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Affiliation(s)
- Hua Li
- Gene Expression and Regulation Program, The Wistar Institute Philadelphia, PA, USA
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245
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Lin S, Shen H, Li JL, Tang S, Gu Y, Chen Z, Hu C, Rice JC, Lu J, Wu L. Proteomic and functional analyses reveal the role of chromatin reader SFMBT1 in regulating epigenetic silencing and the myogenic gene program. J Biol Chem 2013; 288:6238-47. [PMID: 23349461 PMCID: PMC3585059 DOI: 10.1074/jbc.m112.429605] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 01/23/2013] [Indexed: 01/24/2023] Open
Abstract
SFMBT1 belongs to the malignant brain tumor domain-containing chromatin reader family that recognizes repressive histone marks and represses transcription. The biological functions and molecular basis underlying SFMBT1-mediated transcriptional repression are poorly elucidated. Here, our proteomic analysis revealed that SFMBT1 is associated with multiple transcriptional corepressor complexes, including CtBP/LSD1/HDAC complexes, polycomb repressive complexes, and malignant brain tumor family proteins, that collectively contribute to SFMBT1 repressor activity. During myogenesis, Sfmbt1 represses myogenic differentiation of cultured and primary myoblasts. Mechanistically, Sfmbt1 interacts with MyoD and mediates epigenetic silencing of MyoD target genes via recruitment of its associated corepressors and subsequent induction of epigenetic modifications and chromatin compaction. Therefore, our study identified novel mechanisms accounting for SFMBT1-mediated transcription repression and revealed an essential role of Sfmbt1 in regulating MyoD-mediated transcriptional silencing that is required for the maintenance of undifferentiated states of myogenic progenitor cells.
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Affiliation(s)
- Shuibin Lin
- From the Department of Molecular Genetics and Microbiology
| | - Huangxuan Shen
- From the Department of Molecular Genetics and Microbiology
- the State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060 China
| | - Jian-Liang Li
- the Sanford-Burnham Medical Research Institute at Lake Nona, Orlando, Florida 32827
| | | | - Yumei Gu
- From the Department of Molecular Genetics and Microbiology
| | - Zirong Chen
- From the Department of Molecular Genetics and Microbiology
| | - Chengbin Hu
- From the Department of Molecular Genetics and Microbiology
| | - Judd C. Rice
- the Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Jianrong Lu
- Department of Biochemistry and Molecular Biology, Shands Cancer Center, University of Florida, Gainesville, Florida 32610
| | - Lizi Wu
- From the Department of Molecular Genetics and Microbiology
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246
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Diao Y, Guo X, Li Y, Sun K, Lu L, Jiang L, Fu X, Zhu H, Sun H, Wang H, Wu Z. Pax3/7BP is a Pax7- and Pax3-binding protein that regulates the proliferation of muscle precursor cells by an epigenetic mechanism. Cell Stem Cell 2013; 11:231-41. [PMID: 22862948 DOI: 10.1016/j.stem.2012.05.022] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 04/16/2012] [Accepted: 05/11/2012] [Indexed: 11/26/2022]
Abstract
In mouse skeletal muscles, Pax7 uniquely marks muscle satellite cells and plays some important yet unknown functions at the perinatal stage. To elucidate its in vivo functions, we initiated a yeast two-hybrid screening to look for Pax7-interacting proteins and identified a previously uncharacterized Pax7- and Pax3-binding protein (Pax3/7BP). Pax3/7BP is a ubiquitously expressed nuclear protein, enriched in Pax7+ muscle precursor cells (MPCs), and serves as an indispensable adaptor for Pax7 to recruit the histone 3 lysine 4 (H3K4) methyltransferase (HMT) complex by bridging Pax7 and Wdr5. Knockdown of Pax3/7BP abolished the Pax3/7-associated H3K4 HMT activity and inhibited the proliferation of Pax7+ MPCs from young mice both in culture and in vivo. Id3 and Cdc20 were direct target genes of Pax7 and Pax3/7BP involved in the proliferation of Pax7+ MPCs. Collectively, our work establishes Pax3/7BP as an essential adaptor linking Pax3/7 with the H3K4 HMT to regulate the proliferation of MPCs.
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Affiliation(s)
- Yarui Diao
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
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247
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Pal B, Bouras T, Shi W, Vaillant F, Sheridan JM, Fu N, Breslin K, Jiang K, Ritchie ME, Young M, Lindeman GJ, Smyth GK, Visvader JE. Global changes in the mammary epigenome are induced by hormonal cues and coordinated by Ezh2. Cell Rep 2013; 3:411-26. [PMID: 23375371 DOI: 10.1016/j.celrep.2012.12.020] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 12/20/2012] [Accepted: 12/28/2012] [Indexed: 12/21/2022] Open
Abstract
The mammary epithelium is a dynamic, highly hormone-responsive tissue. To explore chromatin modifications underlying its lineage specification and hormone responsiveness, we determined genome-wide histone methylation profiles of mammary epithelial subpopulations in different states. The marked differences in H3K27 trimethylation between subpopulations in the adult gland suggest that epithelial cell-fate decisions are orchestrated by polycomb-complex-mediated repression. Remarkably, the mammary epigenome underwent highly specific changes in different hormonal contexts, with a profound change being observed in the global H3K27me3 map of luminal cells during pregnancy. We therefore examined the role of the key H3K27 methyltransferase Ezh2 in mammary physiology. Its expression and phosphorylation coincided with H3K27me3 modifications and peaked during pregnancy, driven in part by progesterone. Targeted deletion of Ezh2 impaired alveologenesis during pregnancy, preventing lactation, and drastically reduced stem/progenitor cell numbers. Taken together, these findings reveal that Ezh2 couples hormonal stimuli to epigenetic changes that underpin progenitor activity, lineage specificity, and alveolar expansion in the mammary gland.
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Affiliation(s)
- Bhupinder Pal
- ACRF Stem Cells and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville VIC 3052, Australia
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248
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Hong P, Chen K, Huang B, Liu M, Cui M, Rozenberg I, Chaqour B, Pan X, Barton ER, Jiang XC, Siddiqui MAQ. HEXIM1 controls satellite cell expansion after injury to regulate skeletal muscle regeneration. J Clin Invest 2013; 122:3873-87. [PMID: 23023707 DOI: 10.1172/jci62818] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 08/02/2012] [Indexed: 01/07/2023] Open
Abstract
The native capacity of adult skeletal muscles to regenerate is vital to the recovery from physical injuries and dystrophic diseases. Currently, the development of therapeutic interventions has been hindered by the complex regulatory network underlying the process of muscle regeneration. Using a mouse model of skeletal muscle regeneration after injury, we identified hexamethylene bisacetamide inducible 1 (HEXIM1, also referred to as CLP-1), the inhibitory component of the positive transcription elongation factor b (P-TEFb) complex, as a pivotal regulator of skeletal muscle regeneration. Hexim1-haplodeficient muscles exhibited greater mass and preserved function compared with those of WT muscles after injury, as a result of enhanced expansion of satellite cells. Transplanted Hexim1-haplodeficient satellite cells expanded and improved muscle regeneration more effectively than WT satellite cells. Conversely, HEXIM1 overexpression restrained satellite cell proliferation and impeded muscle regeneration. Mechanistically, dissociation of HEXIM1 from P-TEFb and subsequent activation of P-TEFb are required for satellite cell proliferation and the prevention of early myogenic differentiation. These findings suggest a crucial role for the HEXIM1/P-TEFb pathway in the regulation of satellite cell–mediated muscle regeneration and identify HEXIM1 as a potential therapeutic target for degenerative muscular diseases.
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Affiliation(s)
- Peng Hong
- Department of Cell Biology, State University of New York Downstate Medical Center,New York, New York, USA
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249
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Voronova A, Coyne E, Al Madhoun A, Fair JV, Bosiljcic N, St-Louis C, Li G, Thurig S, Wallace VA, Wiper-Bergeron N, Skerjanc IS. Hedgehog signaling regulates MyoD expression and activity. J Biol Chem 2012; 288:4389-404. [PMID: 23266826 PMCID: PMC3567689 DOI: 10.1074/jbc.m112.400184] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inhibition of MyoD expression is important for obtaining muscle progenitors that can replenish the satellite cell niche during muscle repair. Progenitors could be derived from either embryonic stem cells or satellite cells. Hedgehog (Hh) signaling is important for MyoD expression during embryogenesis and adult muscle regeneration. To date, the mechanistic understanding of MyoD regulation by Hh signaling is unclear. Here, we demonstrate that the Hh effector, Gli2, regulates MyoD expression and associates with MyoD gene elements. Gain- and loss-of-function experiments in pluripotent P19 cells show that Gli2 activity is sufficient and required for efficient MyoD expression during skeletal myogenesis. Inhibition of Hh signaling reduces MyoD expression during satellite cell activation in vitro. In addition to regulating MyoD expression, Hh signaling regulates MyoD transcriptional activity, and MyoD activates Hh signaling in myogenic conversion assays. Finally, Gli2, MyoD, and MEF2C form a protein complex, which enhances MyoD activity on skeletal muscle-related promoters. We therefore link Hh signaling to the function and expression of MyoD protein during myogenesis in stem cells.
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Affiliation(s)
- Anastassia Voronova
- Department of Biochemistry, Microbiology, and Immunology, Dasman Diabetes Institute, Dasman 15462, Kuwait
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