Browsing by Subject "Brg1"

Now showing 1 - 4 of 4
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    Epigenetic and lncRNA regulation of cardiac pathophysiology
    (Elsevier, 2016-03-09) Chang, Ching-Pin; Han, Pei; Medicine, School of Medicine
    Our developmental studies provide an insight into the pathogenesis of heart failure in adults. These studies reveal a mechanistic link between fetal cardiomyocytes and pathologically stressed adult cardiomyocytes at the level of chromatin regulation. In embryos, chromatin-regulating factors within the cardiomyocytes respond to developmental signals to program cardiac gene expression to promote cell proliferation and inhibit premature cell differentiation. In the neonatal period, the activity of these developmental chromatin regulators is quickly turned off in cardiomyocytes, coinciding with the cessation of cell proliferation and advance in cell differentiation toward adult maturity. When the mature hearts are pathologically stressed, those chromatin regulators essential for cardiomyocyte development in embryos are reactivated, triggering gene reprogramming to a fetal-like state and pathological cardiac hypertrophy. Furthermore, in the study of chromatin regulation and cardiac gene expression, we identified a long noncoding RNA that interacts with chromatin remodeling factor to regulate the cardiac response to environmental changes. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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    Epigenetic response to environmental stress: Assembly of BRG1–G9a/GLP–DNMT3 repressive chromatin complex on Myh6 promoter in pathologically stressed hearts
    (Elsevier, 2016-03-04) Han, Pei; Li, Wei; Yang, Jin; Shang, Ching; Lin, Chiou-Hong; Cheng, Wei; Hang, Calvin T.; Cheng, Hsiu-Ling; Chen, Chen-Hao; Wong, Johnson; Xiong, Yiqin; Zhao, Mingming; Drakos, Stavros G.; Ghetti, Andrea; Li, Dean Y.; Bernstein, Daniel; Chen, Huei-sheng Vincent; Quertermous, Thomas; Chang, Ching-Pin; Medicine, School of Medicine
    Chromatin structure is determined by nucleosome positioning, histone modifications, and DNA methylation. How chromatin modifications are coordinately altered under pathological conditions remains elusive. Here we describe a stress-activated mechanism of concerted chromatin modification in the heart. In mice, pathological stress activates cardiomyocytes to express Brg1 (nucleosome-remodeling factor), G9a/Glp (histone methyltransferase), and Dnmt3 (DNA methyltransferase). Once activated, Brg1 recruits G9a and then Dnmt3 to sequentially assemble repressive chromatin—marked by H3K9 and CpG methylation—on a key molecular motor gene (Myh6), thereby silencing Myh6 and impairing cardiac contraction. Disruption of Brg1, G9a or Dnmt3 erases repressive chromatin marks and de-represses Myh6, reducing stress-induced cardiac dysfunction. In human hypertrophic hearts, BRG1–G9a/GLP–DNMT3 complex is also activated; its level correlates with H3K9/CpG methylation, Myh6 repression, and cardiomyopathy. Our studies demonstrate a new mechanism of chromatin assembly in stressed hearts and novel therapeutic targets for restoring Myh6 and ventricular function. The stress-induced Brg1–G9a–Dnmt3 interactions and sequence of repressive chromatin assembly on Myh6 illustrates a molecular mechanism by which the heart epigenetically responds to environmental signals. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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    A long non-coding RNA protects the heart from pathological hypertrophy
    (Nature Publishing Group, 2014-10-02) Han, Pei; Li, Wei; Lin, Chiou-Hong; Yang, Jin; Shang, Ching; Nuernberg, Sylvia T.; Jin, Kevin Kai; Xu, Weihong; Lin, Chieh-Yu; Lin, Chien-Jung; Xiong, Yiqin; Chien, Huanchieh; Zhou, Bin; Ashley, Euan; Bernstein, Daniel; Chen, Peng-Sheng; Chen, Huei-sheng Vincent; Quertermous, Thomas; Chang, Ching-Pin; Department of Medicine, IU School of Medicine
    The role of long noncoding RNA (lncRNA) in adult hearts is unknown
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    Pathological Ace2-to-Ace enzyme switch in the stressed heart is transcriptionally controlled by the endothelial Brg1–FoxM1 complex
    (National Academy of Sciences, 2016-09-20) Yang, Jin; Feng, Xuhui; Zhou, Qiong; Cheng, Wei; Shang, Ching; Han, Pei; Lin, Chiou-Hong; Chen, Huei-Sheng Vincent; Quertermous, Thomas; Chang, Ching-Pin; Department of Medicine, IU School of Medicine
    Genes encoding angiotensin-converting enzymes (Ace and Ace2) are essential for heart function regulation. Cardiac stress enhances Ace, but suppresses Ace2, expression in the heart, leading to a net production of angiotensin II that promotes cardiac hypertrophy and fibrosis. The regulatory mechanism that underlies the Ace2-to-Ace pathological switch, however, is unknown. Here we report that the Brahma-related gene-1 (Brg1) chromatin remodeler and forkhead box M1 (FoxM1) transcription factor cooperate within cardiac (coronary) endothelial cells of pathologically stressed hearts to trigger the Ace2-to-Ace enzyme switch, angiotensin I-to-II conversion, and cardiac hypertrophy. In mice, cardiac stress activates the expression of Brg1 and FoxM1 in endothelial cells. Once activated, Brg1 and FoxM1 form a protein complex on Ace and Ace2 promoters to concurrently activate Ace and repress Ace2, tipping the balance to Ace2 expression with enhanced angiotensin II production, leading to cardiac hypertrophy and fibrosis. Disruption of endothelial Brg1 or FoxM1 or chemical inhibition of FoxM1 abolishes the stress-induced Ace2-to-Ace switch and protects the heart from pathological hypertrophy. In human hypertrophic hearts, BRG1 and FOXM1 expression is also activated in endothelial cells; their expression levels correlate strongly with the ACE/ACE2 ratio, suggesting a conserved mechanism. Our studies demonstrate a molecular interaction of Brg1 and FoxM1 and an endothelial mechanism of modulating Ace/Ace2 ratio for heart failure therapy.