Mechanosensitive Gene Regulation by Myocardin-Related Transcription Factors is Required for Cardiomyocyte Integrity in Load-Induced Ventricular Hypertrophy
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE102792 | GEO | 2018/08/13
REPOSITORIES: GEO
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Project description:Myocardin-related transcription factors (MRTFs) play a central role in the regulation of actin expression and cytoskeletal dynamics. Stimuli that promote actin polymerization allow for shuttling of MRTFs to the nucleus where they activate serum response factor (SRF), a regulator of actin and other cytoskeletal protein genes. SRF is an essential regulator of skeletal muscle differentiation and numerous components of the muscle sarcomere, but the potential involvement of MRTFs in skeletal muscle development has not been examined. We explored the role of MRTFs in muscle development in vivo by generating mutant mice harboring a skeletal muscle-specific deletion of MRTF-B and a global deletion of MRTF-A. These double knockout (dKO) mice were able to form sarcomeres during embryogenesis. However, the sarcomeres were abnormally small and disorganized, causing skeletal muscle hypoplasia and perinatal lethality. Transcriptome analysis demonstrated dramatic dysregulation of actin genes in MRTF dKO mice, highlighting the importance of MRTFs in actin cycling and myofibrillogenesis. MRTFs were also necessary for the survival of skeletal myoblasts and for the efficient formation of intact myotubes. Our findings reveal a central role for MRTFs in sarcomere formation during skeletal muscle development and point to the potential involvement of these transcriptional coactivators in skeletal myopathies. Gene expression profile was generated comparing wild type (WT) and HSA-Cre, MRTF-A/B double knockout mice, by deep seqencing, with three biological replicates, using Illumina HiSeq 2500.
2016-08-02 | E-GEOD-84063 | biostudies-arrayexpress
Project description:Myocardin-Related Transcription Factors A and B (MRTF-A and MRTF-B) are highly homologous proteins that function as powerful coactivators of serum response factor (SRF), a ubiquitously expressed transcription factor essential for cardiac development. The SRF/MRTF complex binds to CArG boxes found in the control regions of genes that regulate cytoskeletal dynamics and muscle contraction, among other processes. While SRF is required for heart development and function, the role of MRTFs in the developing or adult heart has not been explored. Through cardiac-specific deletion of MRTF alleles in mice, we show that either MRTF-A or MRTF-B is dispensable for cardiac development and function, whereas deletion of both MRTF-A and MRTF-B causes a spectrum of structural and functional cardiac abnormalities. Defects observed in MRTF-A/B null mice ranged from reduced cardiac contractility and adult onset heart failure to neonatal lethality accompanied by sarcomere disarray. RNA-seq analysis on neonatal hearts identified the most altered pathways in MRTF double knockout hearts as being involved in cytoskeletal organization. Together, these findings demonstrate redundant but essential roles of the MRTFs in maintenance of cardiac structure and function and as indispensible links in cardiac cytoskeletal gene regulatory networks.
2015-12-02 | GSE69726 | GEO
Project description:Myocardin-related transcription factors (MRTFs) play a central role in the regulation of actin expression and cytoskeletal dynamics. Stimuli that promote actin polymerization allow for shuttling of MRTFs to the nucleus where they activate serum response factor (SRF), a regulator of actin and other cytoskeletal protein genes. SRF is an essential regulator of skeletal muscle differentiation and numerous components of the muscle sarcomere, but the potential involvement of MRTFs in skeletal muscle development has not been examined. We explored the role of MRTFs in muscle development in vivo by generating mutant mice harboring a skeletal muscle-specific deletion of MRTF-B and a global deletion of MRTF-A. These double knockout (dKO) mice were able to form sarcomeres during embryogenesis. However, the sarcomeres were abnormally small and disorganized, causing skeletal muscle hypoplasia and perinatal lethality. Transcriptome analysis demonstrated dramatic dysregulation of actin genes in MRTF dKO mice, highlighting the importance of MRTFs in actin cycling and myofibrillogenesis. MRTFs were also necessary for the survival of skeletal myoblasts and for the efficient formation of intact myotubes. Our findings reveal a central role for MRTFs in sarcomere formation during skeletal muscle development and point to the potential involvement of these transcriptional coactivators in skeletal myopathies.
2016-08-02 | GSE84063 | GEO
Project description:ABSTRACT Aims Forced differentiation of non-muscle cells into heart muscle cells using cardiac transcription factors (cTFs) may constitute a novel strategy to accomplish myocardial regeneration. Methods We investigated the potential of the cTF myocardin to induce cardiomyocyte differentiation and compared the myocardin-induced gene expression program to that of fully differentiated cardiomyocytes using oligonucleotide microarray hybridizations, quantitative RT-PCR analyses and immunofluorescence microscopy. The experiments were performed in the recently described human cardiomyocytes progenitor cells (hCMPCs), which differentiate into fully functional cardiomyocytes upon stimulation with 5-azacytidine and transforming growth factor β1. Results and Conclusions Forced myocardin expression stimulated transcription of a surprisingly large repertoire of heart muscle-specific genes in hCMPCs but did not cause their differentiation into functional cardiomyocytes. Specifically, myocardin gene transfer did not stimulate the synthesis of several sarcomeric (regulatory) proteins and ion channel constituents. The heart and smooth muscle-enriched isoforms of myocardin stimulate equally well the transcription of many of their cardiomyocyte-specific and virtually all of their smooth muscle target genes. However, the heart muscle-enriched myocardin species is a much more potent transactivator of a subset of genes encoding mainly cardiomyocyte-specific myofibrillar components. This may explain the underestimation of myocardin's cardiomyogenic potential in previous studies utilizing the smooth muscle-enriched isoform of this cTF.
2008-07-15 | GSE12110 | GEO
Project description:To control transcription, SRF recruits signal-regulated co-activators, the Ternary Complex Factors (TCFs) and the Myocardin-related Transcription Factors (MRTFs), which compete for a common site on its DNA-binding domain. The TCFs - SAP-1, Elk-1 and Net - are Ets proteins that link SRF activity to Ras-ERK signalling. In contrast, the two MRTFs, MRTF-A and MRTF-B, link SRF activity to Rho-actin signalling. In this novel signalling pathway, the actin-binding MRTF RPEL domain acts as a G-actin sensor, controlling MRTF nuclear accumulation in response to signal-induced depletion of the G-actin pool. Previous studies have suggested that the Ras-ERK signalling and Rho-actin pathways control specific subsets of SRF target genes. We used ChIP-seq and RNA-seq to analyse the immediate-early transcriptional response in NIH3T3 fibroblasts, using pathway-specific inhibitors to identify the contributions of Ras-ERK and Rho-actin signalling Chromatin immunoprecipitation and sequencing (ChIP-seq) in NIH3T3 fibroblast after serum stimulation in presence or absence of LatrunculinB or U0126 drugs and using antibodies against SRF, MRTF-A, MRTF-B, SAP1, ELK1, NET, Pol II, PolII S5P, PolII S2P and total H3. Validation by ChIP-PCR. Strand specific total-RNA-seq following DSN normalisation and validation by qRT-PCR from NIH3T3 stimulated by serum or Cytochalasin D in presence or absence of LatrunculinB and/or U0126 drugs.
2014-04-24 | E-GEOD-45888 | biostudies-arrayexpress
Project description:Cardiac hypertrophy and failure are accompanied by a reprogramming of gene expression that involves transcription factors and chromatin remodeling enzymes. Little is known about the role of histone methylation and demethylation in this process. To understand the role of JMJD2A, a trimethyl demethylase for histone 3 lysine 9 and 36, in cardiac hypertrophy, we generated heart specific JMJD2A deletion (JMJD2A hKO) and overexpression (JMJD2A-Tg) mouse lines. JMJD2A hKO and JMJD2A-Tg mice are viable and have no overt baseline phenotype. However, they have altered responses to cardiac stresses. While inactivation of JMJD2A in hKO mice resulted in an attenuated hypertrophic response to transverse aortic constriction (TAC)-induced pressure overload compared to that of control littermates, JMJD2A-Tg mice have exacerbated cardiac hypertrophy after TAC. We identified four-and-a-half LIM domains 1 (FHL1) as a novel target of JMJD2A. JMJD2A binds to the FHL1 promoter in response to TAC and upregulates the expression of FHL1. Binding of JMJD2A to the FHL1 promoter is associated with downregulation of trimethylated H3K9. Upregulation of FHL1 by JMJD2A is mediated through SRF and myocardin, and requires its demethylase activity. The expression of JMJD2A is upregulated in human hypertrophic cardiomyopathy patients. Our studies reveal that JMJD2A promotes cardiac hypertrophy by synergistically upregulating SRF/myocardin-targeted genes and suggest a novel mechanism of reprogramming of gene expression involved in cardiac hypertrophy. Six to eight years old wildtype and JMJD2A heart specific transgnic mice were undergone either sham or TAC surgery. After 3 weeks, mice were sarcirificed to harvest heart. RNA was extracted from heart samples and treated with DNase, followed by biotin-labeling and microarray hybridization.
2011-06-02 | E-GEOD-27689 | biostudies-arrayexpress
Project description:Background: Cardiac transcription factors are master regulators during heart development. Recently, some were shown to transdifferentiate noncardiac mesoderm cells and cardiac fibroblasts into cardiomyocytes. However, the individual roles of each transcription factors in activating cardiac gene program have not been elucidated. We examined cardiac-specific and genome-wide gene expression in fibroblasts induced with cardiac transcription factors Nkx2.5 (N), Tbx5 (T), Gata4 (G), Myocardin (M) alone or different combinations. Methodology/Principal Findings: We applied different combinations of human Nkx2.5 (N), Tbx5 (T), Gata4 (G) and Myocardin (M) lentiviruses into 10T1/2 fibroblasts. Immunostaining and quantitative reverse transcription polymerase chain reaction (qRT-PCR) showed that N, T, G or M alone did not induce expression of cardiac marker genes M-NM-1-myosin heavy chain (M-NM-1MHC) and cardiac troponin T (cTnT). Only T+M and T+G+M combinations induced M-NM-1MHC and cTnT expression. Microarray-based gene ontology analysis revealed that T alone inhibited most genes involved in cardiac-related processes and activated genes involved in Wnt receptor signaling pathway and in aberrant processes. M alone inhibited genes involved in Wnt receptor signaling pathway and activated genes involved in cardiac-related processes and in aberrant processes. G alone inhibited genes involved in ectoderm development. T+G+M combination was the most effective activator of genes associated with cardiac-related processes including muscle cell differentiation, sarcomere, striated muscle contraction, regulation of heart contraction, and glucose metabolism and fatty acid oxidation (two significant forms of cardiomyocyte energy metabolism). And unlike T, M, G alone or T+M, T+G+M did not activate genes associated with aberrant processes. Conclusions: Tbx5, Gata4 and Myocardin play different roles in activating cardiac gene program and in avoiding aberrant gene program activation. The combination of T+G+M activated cardiac gene program and avoided aberrant gene program activation. Two weeks after doxycline induction, total RNA was isolated from 10T1/2-tTA cells infected with different combinations of Tbx5, Gata4, and Myocardin lentiviruses. Biological triplicated.
2012-11-30 | E-GEOD-27329 | biostudies-arrayexpress
Project description:Myocardin-related transcription factors (MRTFs) are coactivators of serum response factor (SRF), and thereby regulate cytoskeletal gene expression in response to actin dynamics. MRTFs have also been implicated in heat shock protein (hsp) transcription in fly ovaries, but the mechanisms remain unclear. Here we demonstrate that in mammalian cells, MRTFs are dispensable for hsp gene induction. However, the widely used small molecule inhibitors of MRTF/SRF transcription pathway, derived from CCG-1423, efficiently inhibit hsp gene transcription in both fly and mammalian cells also in absence of MRTFs. Quantifying RNA synthesis and RNA polymerase distribution demonstrates that CCG-1423-derived compounds have a genome-wide effect on transcription. Indeed, tracking nascent transcription at nucleotide resolution reveals that CCG-1423-derived compounds reduce RNA polymerase II elongation, and severely dampen the transcriptional response to heat shock. The effects of CCG-1423-derived compounds therefore extend beyond the MRTF/SRF pathway into nascent transcription, opening novel opportunities for their use in transcription research.
2023-10-03 | GSE244231 | GEO
Project description:Myocardin-related transcription factors (MRTFs) are coactivators of serum response factor (SRF), and thereby regulate cytoskeletal gene expression in response to actin dynamics. MRTFs have also been implicated in heat shock protein (hsp) transcription in fly ovaries, but the mechanisms remain unclear. Here we demonstrate that in mammalian cells, MRTFs are dispensable for hsp gene induction. However, the widely used small molecule inhibitors of MRTF/SRF transcription pathway, derived from CCG-1423, efficiently inhibit hsp gene transcription in both fly and mammalian cells also in absence of MRTFs. Quantifying RNA synthesis and RNA polymerase distribution demonstrates that CCG-1423-derived compounds have a genome-wide effect on transcription. Indeed, tracking nascent transcription at nucleotide resolution reveals that CCG-1423-derived compounds reduce RNA polymerase II elongation, and severely dampen the transcriptional response to heat shock. The effects of CCG-1423-derived compounds therefore extend beyond the MRTF/SRF pathway into nascent transcription, opening novel opportunities for their use in transcription research.
2023-09-26 | GSE243873 | GEO
Project description:To control transcription, SRF recruits signal-regulated co-activators, the Ternary Complex Factors (TCFs) and the Myocardin-related Transcription Factors (MRTFs), which compete for a common site on its DNA-binding domain. The TCFs - SAP-1, Elk-1 and Net - are Ets proteins that link SRF activity to Ras-ERK signalling. In contrast, the two MRTFs, MRTF-A and MRTF-B, link SRF activity to Rho-actin signalling. In this novel signalling pathway, the actin-binding MRTF RPEL domain acts as a G-actin sensor, controlling MRTF nuclear accumulation in response to signal-induced depletion of the G-actin pool. Previous studies have suggested that the Ras-ERK signalling and Rho-actin pathways control specific subsets of SRF target genes. We used ChIP-seq and RNA-seq to analyse the immediate-early transcriptional response in NIH3T3 fibroblasts, using pathway-specific inhibitors to identify the contributions of Ras-ERK and Rho-actin signalling
2014-04-24 | GSE45888 | GEO