1
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Mellis IA, Edelstein HI, Truitt R, Goyal Y, Beck LE, Symmons O, Dunagin MC, Linares Saldana RA, Shah PP, Pérez-Bermejo JA, Padmanabhan A, Yang W, Jain R, Raj A. Responsiveness to perturbations is a hallmark of transcription factors that maintain cell identity in vitro. Cell Syst 2021; 12:885-899.e8. [PMID: 34352221 DOI: 10.1016/j.cels.2021.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/27/2020] [Accepted: 07/09/2021] [Indexed: 02/07/2023]
Abstract
Identifying the particular transcription factors that maintain cell type in vitro is important for manipulating cell type. Identifying such transcription factors by their cell-type-specific expression or their involvement in developmental regulation has had limited success. We hypothesized that because cell type is often resilient to perturbations, the transcriptional response to perturbations would reveal identity-maintaining transcription factors. We developed perturbation panel profiling (P3) as a framework for perturbing cells across many conditions and measuring gene expression responsiveness transcriptome-wide. In human iPSC-derived cardiac myocytes, P3 showed that transcription factors important for cardiac myocyte differentiation and maintenance were among the most frequently upregulated (most responsive). We reasoned that one function of responsive genes may be to maintain cellular identity. We identified responsive transcription factors in fibroblasts using P3 and found that suppressing their expression led to enhanced reprogramming. We propose that responsiveness to perturbations is a property of transcription factors that help maintain cellular identity in vitro. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Ian A Mellis
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Genomics and Computational Biology Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hailey I Edelstein
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rachel Truitt
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yogesh Goyal
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lauren E Beck
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Orsolya Symmons
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Margaret C Dunagin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ricardo A Linares Saldana
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Parisha P Shah
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Arun Padmanabhan
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA; Division of Cardiology, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Wenli Yang
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rajan Jain
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Arjun Raj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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2
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A myocardin-adjacent lncRNA balances SRF-dependent gene transcription in the heart. Genes Dev 2021; 35:835-840. [PMID: 33985971 PMCID: PMC8168554 DOI: 10.1101/gad.348304.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/09/2021] [Indexed: 01/23/2023]
Abstract
In this study, Anderson et al. identify a cardiac lncRNA transcribed adjacent to myocardin, named CARDINAL, that antagonizes SRF-dependent mitogenic gene transcription in the heart. They also show that CARDINAL forms a nuclear complex with SRF and inhibits TCF-mediated transactivation of the promitogenic gene c-fos, suggesting CARDINAL functions as an essential RNA cofactor for SRF in the heart. Myocardin, a potent coactivator of serum response factor (SRF), competes with ternary complex factor (TCF) proteins for SRF binding to balance opposing mitogenic and myogenic gene programs in cardiac and smooth muscle. Here we identify a cardiac lncRNA transcribed adjacent to myocardin, named CARDINAL, which antagonizes SRF-dependent mitogenic gene transcription in the heart. CARDINAL-deficient mice show ectopic TCF/SRF-dependent mitogenic gene expression and decreased cardiac contractility in response to age and ischemic stress. CARDINAL forms a nuclear complex with SRF and inhibits TCF-mediated transactivation of the promitogenic gene c-fos, suggesting CARDINAL functions as an RNA cofactor for SRF in the heart.
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3
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Xu Y, Liang C, Luo Y, Zhang T. MBNL1 regulates isoproterenol-induced myocardial remodelling in vitro and in vivo. J Cell Mol Med 2021; 25:1100-1115. [PMID: 33295096 PMCID: PMC7812249 DOI: 10.1111/jcmm.16177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/15/2020] [Accepted: 11/25/2020] [Indexed: 12/21/2022] Open
Abstract
Myocardial remodelling is a common phenomenon in cardiovascular diseases, which threaten human health and the quality of life. Due to the lack of effective early diagnosis and treatment methods, the molecular mechanism of myocardial remodelling should be explored in depth. In this study, we observed the high expression of MBNL1 in cardiac tissue and peripheral blood of an isoproterenol (ISO)-induced cardiac hypertrophy mouse model. MBNL1 promoted ISO-induced cardiac hypertrophy and fibrosis by stabilizing Myocardin mRNA in vivo and in vitro. Meanwhile, an increase in MBNL1 may induce the apoptosis of cardiomyocytes treated with ISO via TNF-α signalling. Interestingly, MBNL1 can be activated by p300 in cardiomyocytes treated with ISO. At last, Myocardin can reverse activate the expression of MBNL1. These results suggest that MBNL1 may be a potential target for the early diagnosis and clinical treatment of myocardial remodelling.
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Affiliation(s)
- Yao Xu
- College of Life Sciences and HealthWuhan University of Science and TechnologyWuhanChina
| | - Chen Liang
- College of Life Sciences and HealthWuhan University of Science and TechnologyWuhanChina
| | - Ying Luo
- College of Biological Science and TechnologyHubei Minzu UniversityEnshiChina
- Hubei Provincial Key Laboratory of Occurrence and Intervention of Rheumatic diseasesHubei Minzu UniversityEnshiChina
| | - Tongcun Zhang
- College of Life Sciences and HealthWuhan University of Science and TechnologyWuhanChina
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4
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Hou J, Liu B, Zhu B, Wang D, Qiao Y, Luo E, Nawabi AQ, Yan G, Tang C. Role of integrin-linked kinase in the hypoxia-induced phenotypic transition of pulmonary artery smooth muscle cells: Implications for hypoxic pulmonary hypertension. Exp Cell Res 2019; 382:111476. [PMID: 31255599 DOI: 10.1016/j.yexcr.2019.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 06/13/2019] [Accepted: 06/19/2019] [Indexed: 11/21/2022]
Abstract
The phenotypic transition of pulmonary artery smooth muscle cells (PASMCs) from a contractile/differentiated to synthetic/de-differentiated phenotype is an important mechanism for the occurrence and development of hypoxic pulmonary hypertension (HPH). Integrin-linked kinase (ILK) is an early hypoxic response factor whose kinase activity is significantly affected during early hypoxia. Myocardin and ETS-like protein 1 (Elk-1) are co-activators of serum response factor (SRF) and can bind to SRF to mediate the phenotypic transition of PASMCs. However, little is known about the role of ILK on the phenotypic transition of these PASMCs. Thus, in our study, we explored the role of ILK in this process. We found that the expression of ILK and myocardin decreased gradually with the increase in hypoxia exposure time in the pulmonary arteries of rats. We observed that hypoxia exposure for 1 h caused an increase in the phosphorylation of Elk-1 but did not affect the expression of ILK, myocardin, or SRF. Exposure to hypoxic treatment for 1 h decreased ILK kinase activity and caused Elk-1 to suppress myocardin binding to SRF and the smooth muscle (SM) α-actin gene promoters. In addition, hypoxia exposure for 24 h decreased the expression of ILK, myocardin, SM α-actin, and calponin but increased the expression of osteopontin. Silencing of the myocardin gene significantly decreased the expression of SM α-actin and calponin but increased the expression of osteopontin. Silencing of the ILK gene significantly decreased the expression of myocardin, SM α-actin, and calponin but increased the expression of osteopontin. ILK overexpression reversed the effects of 24 h of hypoxia on the expression of myocardin, SM α-actin, calponin, and osteopontin and reversed the decrease in binding of myocardin to the SM α-actin promoter caused by 24 h of hypoxia exposure. Thus, our results suggest that ILK initiates the phenotypic transition of PASMCs. The underlying mechanism may involve hypoxia downregulating ILK kinase activity and protein expression, causing Elk-1 to compete with myocardin for binding to the SM α-actin promoter, which downregulates the expression of the downstream target myocardin and results in the phenotypic transition of PASMCs from a contractile to a synthetic phenotype. This may be an important mechanism in the development of HPH.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Animals
- Biomarkers/metabolism
- Calcium-Binding Proteins/metabolism
- Cell Hypoxia/genetics
- Cobalt/pharmacology
- Down-Regulation/genetics
- Hemodynamics/genetics
- Hypertension, Pulmonary/complications
- Hypertension, Pulmonary/enzymology
- Hypertension, Pulmonary/pathology
- Hypertension, Pulmonary/physiopathology
- Hypoxia/complications
- Hypoxia/enzymology
- Hypoxia/pathology
- Male
- Microfilament Proteins/metabolism
- Models, Biological
- Myocytes, Smooth Muscle/enzymology
- Myocytes, Smooth Muscle/pathology
- Nuclear Proteins/metabolism
- Osteopontin/metabolism
- Phenotype
- Phosphorylation
- Promoter Regions, Genetic/genetics
- Protein Binding
- Protein Serine-Threonine Kinases/metabolism
- Pulmonary Artery/pathology
- Pulmonary Artery/physiopathology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats, Sprague-Dawley
- Serum Response Factor/metabolism
- Trans-Activators/metabolism
- Vascular Remodeling/genetics
- ets-Domain Protein Elk-1/metabolism
- Calponins
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Affiliation(s)
- Jiantong Hou
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China
| | - Bo Liu
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China
| | - Boqian Zhu
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China
| | - Dong Wang
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China
| | - Yong Qiao
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China
| | - Erfei Luo
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China
| | - Abdul Qadir Nawabi
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China
| | - Gaoliang Yan
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China.
| | - Chengchun Tang
- Department of Cardiology, Zhongda Hospital of Southeast University Medical School, Nanjing, China.
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5
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Yue B, Li H, Liu M, Wu J, Li M, Lei C, Huang B, Chen H. Characterization of lncRNA-miRNA-mRNA Network to Reveal Potential Functional ceRNAs in Bovine Skeletal Muscle. Front Genet 2019; 10:91. [PMID: 30842787 PMCID: PMC6391848 DOI: 10.3389/fgene.2019.00091] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/29/2019] [Indexed: 01/14/2023] Open
Abstract
There is growing evidence that non-coding RNAs are emerging as critical regulators of skeletal muscle development. In order to reveal their functional roles and regulatory mechanisms, we constructed a lncRNA–miRNA–mRNA network according to the ceRNA (competitive endogenous RNA) theory, using our high-throughput sequencing data. Subsequently, the network analysis, GO (Gene Ontology) analysis, and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis were performed for functional annotation and exploration of lncRNA ceRNAs. The results uncovered a scale-free characteristics network which exhibited high functional specificity for bovine skeletal muscle development: co-expression lncRNAs were significantly enriched in muscle development related biological processes and the Wnt signaling pathway. Furthermore, GSEA (Gene Set Enrichment Analysis) indicated that the risk score has a tendency to associate with myogenesis, and differentially expressed RNAs were validated by qPCR, further confirming the credibility of our network. In summary, this study provides insights into lncRNA-mediated ceRNA function and mechanisms in bovine skeletal muscle development and will expand our understanding of lncRNA biology in mammals.
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Affiliation(s)
- Binglin Yue
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Hui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, China
| | - Mei Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jiyao Wu
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Mingxun Li
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Chuzhao Lei
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Bizhi Huang
- Yunnan Academy of Grassland and Animal Science, Kunming, China
| | - Hong Chen
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
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6
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Kamar A, Fahed AC, Shibbani K, El-Hachem N, Bou-Slaiman S, Arabi M, Kurban M, Seidman JG, Seidman CE, Haidar R, Baydoun E, Nemer G, Bitar F. A Novel Role for CSRP1 in a Lebanese Family with Congenital Cardiac Defects. Front Genet 2017; 8:217. [PMID: 29326753 PMCID: PMC5741687 DOI: 10.3389/fgene.2017.00217] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/04/2017] [Indexed: 12/12/2022] Open
Abstract
Despite an obvious role for consanguinity in congenital heart disease (CHD), most studies fail to document a monogenic model of inheritance except for few cases. We hereby describe a first-degree cousins consanguineous Lebanese family with 7 conceived children: 2 died in utero of unknown causes, 3 have CHD, and 4 have polydactyly. The aim of the study is to unveil the genetic variant(s) causing these phenotypes using next generation sequencing (NGS) technology. Targeted exome sequencing identified a heterozygous duplication in CSRP1 which leads to a potential frameshift mutation at position 154 of the protein. This mutation is inherited from the father, and segregates only with the CHD phenotype. The in vitro characterization demonstrates that the mutation dramatically abrogates its transcriptional activity over cardiac promoters like NPPA. In addition, it differentially inhibits the physical association of CSRP1 with SRF, GATA4, and with the newly described partner herein TBX5. Whole exome sequencing failed to show any potential variant linked to polydactyly, but revealed a novel missense mutation in TRPS1. This mutation is inherited from the healthy mother, and segregating only with the cardiac phenotype. Both TRPS1 and CSRP1 physically interact, and the mutations in each abrogate their partnership. Our findings add fundamental knowledge into the molecular basis of CHD, and propose the di-genic model of inheritance as responsible for such malformations.
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Affiliation(s)
- Amina Kamar
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Akl C Fahed
- Department of Genetics, Harvard Medical School, Boston, MA, United States.,Department of Medicine, Massachusetts General Hospital, Boston, MA, United States.,Division of Cardiology, Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA, United States
| | - Kamel Shibbani
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | - Nehme El-Hachem
- Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Salim Bou-Slaiman
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | - Mariam Arabi
- Department of Pediatrics and Adolescent Medicine, American University of Beirut, Beirut, Lebanon
| | - Mazen Kurban
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon.,Department of Dermatology, American University of Beirut, Beirut, Lebanon.,Department of Dermatology, Columbia University, New York, NY, United States
| | - Jonathan G Seidman
- Department of Genetics, Harvard Medical School, Boston, MA, United States
| | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, MA, United States.,Division of Cardiology, Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA, United States
| | - Rachid Haidar
- Department of Surgery, American University of Beirut, Beirut, Lebanon
| | - Elias Baydoun
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Georges Nemer
- Department of Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Fadi Bitar
- Department of Pediatrics and Adolescent Medicine, American University of Beirut, Beirut, Lebanon
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7
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Marrone AK, Shcherbata HR. Dystrophin Orchestrates the Epigenetic Profile of Muscle Cells Via miRNAs. Front Genet 2011; 2:64. [PMID: 22303359 PMCID: PMC3268617 DOI: 10.3389/fgene.2011.00064] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 08/26/2011] [Indexed: 12/02/2022] Open
Abstract
Mammalian musculature is a very robust and dynamic tissue that goes through many rounds of degeneration and regeneration in an individual’s lifetime. There is a biological program that maintains muscle progenitor cells that, when activated, give rise to intermediate myoblast progeny that consequently differentiate into mature muscle cells. Recent works have provided a picture of the role that microRNAs (miRNAs) play in maintaining aspects of this program. Intriguingly, a subset of these miRNAs is de-regulated in muscular dystrophies (MDs), a group of fatal inherited neuromuscular disorders that are often associated with deficiencies in the Dystrophin (Dys) complex. Apparently, transcriptional expression of many of the muscle specific genes and miRNAs is dependent on chromatin state regulated by the Dys–Syn–nNOS pathway. This puts Dystrophin at the epicenter of a highly regulated program of muscle gene expression in which miRNAs help to coordinate networking between multiple phases of muscle maintenance, degeneration, and regeneration. Therefore, understanding the role of miRNAs in physiology of normal and diseased muscle tissue could be useful for future applications in improving the MD therapies and could open new clinical perspectives.
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Affiliation(s)
- April K Marrone
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry Goettingen, Germany
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8
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Zhang X, Azhar G, Helms S, Burton B, Huang C, Zhong Y, Gu X, Fang H, Tong W, Wei JY. Identification of New SRF Binding Sites in Genes Modulated by SRF Over-Expression in Mouse Hearts. GENE REGULATION AND SYSTEMS BIOLOGY 2011; 5:41-59. [PMID: 21792293 PMCID: PMC3140411 DOI: 10.4137/grsb.s7457] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Background: To identify in vivo new cardiac binding sites of serum response factor (SRF) in genes and to study the response of these genes to mild over-expression of SRF, we employed a cardiac-specific, transgenic mouse model, with mild over-expression of SRF (Mild-O SRF Tg). Methodology: Microarray experiments were performed on hearts of Mild-O-SRF Tg at 6 months of age. We identified 207 genes that are important for cardiac function that were differentially expressed in vivo. Among them the promoter region of 192 genes had SRF binding motifs, the classic CArG or CArG-like (CArG-L) elements. Fifty-one of the 56 genes with classic SRF binding sites had not been previously reported. These SRF-modulated genes were grouped into 12 categories based on their function. It was observed that genes associated with cardiac energy metabolism shifted toward that of carbohydrate metabolism and away from that of fatty acid metabolism. The expression of genes that are involved in transcription and ion regulation were decreased, but expression of cytoskeletal genes was significantly increased. Using public databases of mouse models of hemodynamic stress (GEO database), we also found that similar altered expression of the SRF-modulated genes occurred in these hearts with cardiac ischemia or aortic constriction as well. Conclusion and significance: SRF-modulated genes are actively regulated under various physiological and pathological conditions. We have discovered that a large number of cardiac genes have classic SRF binding sites and were significantly modulated in the Mild-O-SRF Tg mouse hearts. Hence, the mild elevation of SRF protein in the heart that is observed during typical adult aging may have a major impact on many SRF-modulated genes, thereby affecting cardiac structure and performance. The results from our study could help to enhance our understanding of SRF regulation of cellular processes in the aged heart.
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Affiliation(s)
- Xiaomin Zhang
- Donald W. Reynolds Department of Geriatrics, The University of Arkansas for Medical Sciences and Geriatric Research, Education, and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, USA
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9
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Zhang X, Azhar G, Huang C, Cui C, Zhong Y, Huck S, Wei JY. Alternative splicing and nonsense-mediated mRNA decay regulate gene expression of serum response factor. Gene 2007; 400:131-9. [PMID: 17629633 DOI: 10.1016/j.gene.2007.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 05/23/2007] [Accepted: 06/05/2007] [Indexed: 11/21/2022]
Abstract
Serum response factor (SRF) is an important transcription factor that regulates a variety of genes in many tissues during development, maturation and aging. The SRF protein also controls the expression of SRF target genes, including the SRF gene itself. However, it is incompletely established how SRF isoforms contribute to the regulation of SRF gene expression. In the present study, we report the identification of three novel SRF isoforms in human tissue. We found that one novel isoform, SRF-triangle up3, contained a premature termination codon (PTC), which was a target of nonsense-mediated mRNA decay (NMD). By contrast, the SRF-triangle up345 isoform protein was able to specifically bind to the serum response element, and to repress the SRF gene promoter activity. Therefore, we propose that SRF isoforms regulate expression of the SRF gene via two different mechanisms. One mechanism is to reduce the abundance of SRF transcripts via coupled alternative splicing and NMD, the other one is to regulate the SRF gene expression via a feedback mechanism in which the SRF isoform proteins bind to the SRF gene promoter region. Analysis of hundreds of SRF cDNA clones derived from human hearts of fetuses, young adults, old and very old individuals revealed that SRF isoform transcripts were increased in the human heart with advancing age. Our data indicate that the SRF isoforms were differentially expressed in the human versus mouse cardiac muscle. Alternative splicing and NMD likely maintain a delicate balance of SRF transcripts and/or proteins among the full-length SRF form and various SRF isoforms that are critical to the regulation of many SRF target genes, including the SRF gene itself.
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Affiliation(s)
- Xiaomin Zhang
- Donald W. Reynolds Department of Geriatrics, University of Arkansas for Medical Sciences and Geriatric Research, Education, and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States
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10
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Sun Y, Boyd K, Xu W, Ma J, Jackson CW, Fu A, Shillingford JM, Robinson GW, Hennighausen L, Hitzler JK, Ma Z, Morris SW. Acute myeloid leukemia-associated Mkl1 (Mrtf-a) is a key regulator of mammary gland function. Mol Cell Biol 2006; 26:5809-26. [PMID: 16847333 PMCID: PMC1592762 DOI: 10.1128/mcb.00024-06] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Transcription of immediate-early genes--as well as multiple genes affecting muscle function, cytoskeletal integrity, apoptosis control, and wound healing/angiogenesis--is regulated by serum response factor (Srf). Extracellular signals regulate Srf in part via a pathway involving megakaryoblastic leukemia 1 (Mkl1, also known as myocardin-related transcription factor A [Mrtf-a]), which coactivates Srf-responsive genes downstream of Rho GTPases. Here we investigate Mkl1 function using gene targeting and show the protein to be essential for the physiologic preparation of the mammary gland during pregnancy and the maintenance of lactation. Lack of Mkl1 causes premature involution and impairs expression of Srf-dependent genes in the mammary myoepithelial cells, which control milk ejection following oxytocin-induced contraction. Despite the importance of Srf in multiple transcriptional pathways and widespread Mkl1 expression, the spectrum of abnormalities associated with Mkl1 absence appears surprisingly restricted.
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MESH Headings
- Animals
- Animals, Newborn
- Apoptosis
- Child
- Failure to Thrive
- Female
- Gene Expression Profiling
- Gene Expression Regulation
- Gene Targeting
- Heart/anatomy & histology
- Heart/embryology
- Humans
- Infant
- Lactation/physiology
- Leukemia, Megakaryoblastic, Acute
- Male
- Mammary Glands, Animal/abnormalities
- Mammary Glands, Animal/anatomy & histology
- Mammary Glands, Animal/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Milk
- Myocytes, Cardiac/pathology
- Myocytes, Cardiac/ultrastructure
- Oligonucleotide Array Sequence Analysis
- Oxytocin/metabolism
- Pregnancy
- Prolactin/metabolism
- STAT3 Transcription Factor
- Serum Response Factor/genetics
- Serum Response Factor/metabolism
- Trans-Activators/genetics
- Trans-Activators/metabolism
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Affiliation(s)
- Yi Sun
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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11
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Li J, Shiroyanagi Y, Lin G, Haqq C, Lin CS, Lue TF, Willingham E, Baskin LS. Serum response factor, its cofactors, and epithelial-mesenchymal signaling in urinary bladder smooth muscle formation. Differentiation 2006; 74:30-9. [PMID: 16466398 DOI: 10.1111/j.1432-0436.2006.00057.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Little is known about the mechanism of bladder smooth muscle differentiation. We hypothesize that epithelial-mesenchymal signaling induces the expression of smooth muscle proteins in bladder mesenchyme resulting in smooth muscle differentiation. We confirmed that smooth muscle differentiation in the mouse urinary bladder occurs first at gestational day 14 (E14) based upon immunohistochemical localization of smooth muscle alpha-actin (SMAA). To investigate murine bladder smooth muscle differentiation and epithlelial-mesenchymal signaling in the developing bladder, we analyzed gene expression profiles of intact embryonic murine bladders and separated epithelial and mesenchymal components at embryonic days E13, E14, E15, E16, and postnatal day 1 (P1). Using cDNA microarray, we identified regulators of vascular smooth muscle differentiation in bladder mesenchyme, including serum response factor (SRF) and its cofactors, ELK1 and SRF accessory protein (SAP)1, as well as two SRF-associated pathways, angiotension receptor II and transforming growth factor- beta2. Immunohistochemistry showed diffuse expression of SRF in the bladder at E12 with localization of expression to the peripheral mesenchyme at E13 and E14. Our results suggest that bladder smooth muscle differentiation may share a similar gene expression program as occurs during vascular smooth muscle differentiation. The unique structure of the urinary bladder makes it an ideal model for studies of smooth muscle differentiation and epithelial-mesenchymal signaling.
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Affiliation(s)
- Jiang Li
- Department of Urology University of California 400 Parnassus Avenue, ACC-610 California 94143-0738 San Francisco, USA
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12
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Chen JF, Mandel EM, Thomson JM, Wu Q, Callis TE, Hammond SM, Conlon FL, Wang DZ. The role of microRNA-1 and microRNA-133 in skeletal muscle proliferation and differentiation. Nat Genet 2005; 38:228-33. [PMID: 16380711 PMCID: PMC2538576 DOI: 10.1038/ng1725] [Citation(s) in RCA: 2094] [Impact Index Per Article: 110.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 10/27/2005] [Indexed: 12/11/2022]
Abstract
Understanding the molecular mechanisms that regulate cellular proliferation and differentiation is a central theme of developmental biology. MicroRNAs (miRNAs) are a class of regulatory RNAs of approximately 22 nucleotides that post-transcriptionally regulate gene expression. Increasing evidence points to the potential role of miRNAs in various biological processes. Here we show that miRNA-1 (miR-1) and miRNA-133 (miR-133), which are clustered on the same chromosomal loci, are transcribed together in a tissue-specific manner during development. miR-1 and miR-133 have distinct roles in modulating skeletal muscle proliferation and differentiation in cultured myoblasts in vitro and in Xenopus laevis embryos in vivo. miR-1 promotes myogenesis by targeting histone deacetylase 4 (HDAC4), a transcriptional repressor of muscle gene expression. By contrast, miR-133 enhances myoblast proliferation by repressing serum response factor (SRF). Our results show that two mature miRNAs, derived from the same miRNA polycistron and transcribed together, can carry out distinct biological functions. Together, our studies suggest a molecular mechanism in which miRNAs participate in transcriptional circuits that control skeletal muscle gene expression and embryonic development.
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Affiliation(s)
- Jian-Fu Chen
- Carolina Cardiovascular Biology Center
- Department of Cell and Developmental Biology
| | | | | | - Qiulian Wu
- Carolina Cardiovascular Biology Center
- Department of Cell and Developmental Biology
| | - Thomas E Callis
- Carolina Cardiovascular Biology Center
- Department of Cell and Developmental Biology
| | | | - Frank L Conlon
- Carolina Cardiovascular Biology Center
- Department of Biology and
- Department of Genetics, University of North Carolina Chapel Hill, North Carolina 27599, USA
| | - Da-Zhi Wang
- Carolina Cardiovascular Biology Center
- Department of Cell and Developmental Biology
- Correspondence should be addressed to D.-Z.W. ()
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13
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Affiliation(s)
- Jau-Nian Chen
- University of California Los Angeles, Los Angeles, CA, USA
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14
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Han Z, Li X, Wu J, Olson EN. A myocardin-related transcription factor regulates activity of serum response factor in Drosophila. Proc Natl Acad Sci U S A 2004; 101:12567-72. [PMID: 15314239 PMCID: PMC515097 DOI: 10.1073/pnas.0405085101] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Serum response factor (SRF) regulates genes involved in cell proliferation, migration, cytoskeletal organization, and myogenesis. Myocardin and myocardin-related transcription factors (MRTFs) act as powerful transcriptional coactivators of SRF in mammalian cells. We describe an MRTF from Drosophila, called DMRTF, which shares high homology with the functional domains of mammalian myocardin and MRTFs. DMRTF forms a ternary complex with and stimulates the activity of Drosophila SRF, which has been implicated in branching of the tracheal (respiratory) system and formation of wing interveins. A loss-of-function mutation introduced into the DMRTF locus by homologous recombination results in abnormalities in tracheal branching similar to those in embryos lacking SRF. Misexpression in wing imaginal discs of a dominant negative DMRTF mutant also causes a diminution of wing interveins, whereas overexpression of DMRTF results in excess intervein tissue, abnormalities reminiscent of SRF loss- and gain-of-function phenotypes, respectively. Overexpression of these DMRTF mutants in mesoderm and in the tracheal system also perturbs mesoderm cell migration and tracheal branching, respectively. We conclude that the interaction of MRTFs with SRF represents an ancient protein partnership involved in cytoplasmic outgrowth and cell migration during development.
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Affiliation(s)
- Zhe Han
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX 75390, USA
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15
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Abstract
A potentially important mechanism controlling ion channel expression is homeostatic regulation, which can act to maintain a stable electrophysiological phenotype in cardiac myocytes as well as to provide plasticity in response to genetic, pathological, or pharmacological insults. The capabilities and limitations of the homeostatic regulatory mechanisms that contribute to the control of cardiac ion channel expression are the primary topic of this review.
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Affiliation(s)
- Barbara Rosati
- Department of Physiology and Biophysics, Institute of Molecular Cardiology, State University of New York at Stony Brook, Stony Brook, NY, USA
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