Cardiac Overexpression of Myotrophin Triggers Myocardial Hypertrophy and Heart Failure in Transgenic Mice

Cardiac hypertrophy and heart failure remain leading causes of death in the United States. Many studies have suggested that, under stress, myocardium releases factors triggering protein synthesis and stimulating myocyte growth. We identified and cloned myotrophin, a 12-kDa protein from hypertrophied human and rat hearts. Myotrophin (whose gene is localized on human chromosome 7q33) stimulates myocyte growth and participates in cellular interaction that initiates cardiac hypertrophyin vitro. In this report, we present data on the pathophysiological significance of myotrophinin vivo, showing the effects of overexpression of cardio-specific myotrophin in transgenic mice in which cardiac hypertrophy occurred by 4 weeks of age and progressed to heart failure by 9-12 months. This hypertrophy was associated with increased expression of proto-oncogenes, hypertrophy marker genes, growth factors, and cytokines, with symptoms that mimicked those of human cardiomyopathy, functionally and morphologically. This model provided a unique opportunity to analyze gene clusters that are differentially up-regulated during initiation of hypertrophyversustransition of hypertrophy to heart failure. Importantly, changes in gene expression observed during initiation of hypertrophy were significantly different from those seen during its transition to heart failure. Our data show that overexpression of myotrophin results in initiation of cardiac hypertrophy that progresses to heart failure, similar to changes in human heart failure. Knowledge of the changes that take place as a result of overexpression of myotrophin at both the cellular and molecular levels will suggest novel strategies for treatment to prevent hypertrophy and its progression to heart failure.

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Transcription factor CHF1/Hey2 suppresses cardiac hypertrophy through an inhibitory interaction with GATA4

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01106.2005 ◽

2006 ◽

Vol 290 (5) ◽

pp. H1997-H2006 ◽

Cited By ~ 35

Author(s):

Fan Xiang ◽

Yasuhiko Sakata ◽

Lei Cui ◽

Joey M. Youngblood ◽

Hironori Nakagami ◽

...

Keyword(s):

Transcription Factor ◽

Transgenic Mice ◽

Cardiac Hypertrophy ◽

Marker Genes ◽

Recognition Sequence ◽

Inhibitory Interaction ◽

Hypertrophic Response ◽

Neonatal Cardiomyocytes

Pathological cardiac hypertrophy is considered a precursor to clinical heart failure. Understanding the transcriptional regulators that suppress the hypertrophic response may have profound implications for the treatment of heart disease. We report the generation of transgenic mice that overexpress the transcription factor CHF1/Hey2 in the myocardium. In response to the α-adrenergic agonist phenylephrine, they show marked attenuation in the hypertrophic response compared with wild-type controls, even though blood pressure is similar in both groups. Isolated myocytes from transgenic mice demonstrate a similar resistance to phenylephrine-induced hypertrophy in vitro, providing further evidence that the protective effect of CHF1/Hey2 is mediated at the myocyte level. Induction of the hypertrophy marker genes ANF, BNP, and β- MHC in the transgenic cells is concurrently suppressed in vivo and in vitro, demonstrating that the induction of hypertrophy-associated genes is repressed by CHF1/Hey2. Transfection of CHF1/Hey2 into neonatal cardiomyocytes suppresses activation of an ANF reporter plasmid by the transcription factor GATA4, which has previously been shown to activate a hypertrophic transcriptional program. Furthermore, CHF1/Hey2 binds GATA4 directly in coimmunoprecipitation assays and inhibits the binding of GATA4 to its recognition sequence within the ANF promoter. Our findings demonstrate that CHF1/Hey2 functions as an antihypertrophic gene, possibly through inhibition of a GATA4-dependent hypertrophic program.

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Growth hormone-releasing hormone attenuates cardiac hypertrophy and improves heart function in pressure overload-induced heart failure

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1712612114 ◽

2017 ◽

Vol 114 (45) ◽

pp. 12033-12038 ◽

Cited By ~ 17

Author(s):

Iacopo Gesmundo ◽

Michele Miragoli ◽

Pierluigi Carullo ◽

Letizia Trovato ◽

Veronica Larcher ◽

...

Keyword(s):

Heart Failure ◽

Growth Hormone ◽

Cardiac Hypertrophy ◽

Cardiac Function ◽

Therapeutic Potential ◽

Growth Hormone Releasing Hormone ◽

Transverse Aortic Constriction ◽

Aortic Constriction

It has been shown that growth hormone-releasing hormone (GHRH) reduces cardiomyocyte (CM) apoptosis, prevents ischemia/reperfusion injury, and improves cardiac function in ischemic rat hearts. However, it is still not known whether GHRH would be beneficial for life-threatening pathological conditions, like cardiac hypertrophy and heart failure (HF). Thus, we tested the myocardial therapeutic potential of GHRH stimulation in vitro and in vivo, using GHRH or its agonistic analog MR-409. We show that in vitro, GHRH(1-44)NH2 attenuates phenylephrine-induced hypertrophy in H9c2 cardiac cells, adult rat ventricular myocytes, and human induced pluripotent stem cell-derived CMs, decreasing expression of hypertrophic genes and regulating hypertrophic pathways. Underlying mechanisms included blockade of Gq signaling and its downstream components phospholipase Cβ, protein kinase Cε, calcineurin, and phospholamban. The receptor-dependent effects of GHRH also involved activation of Gαs and cAMP/PKA, and inhibition of increase in exchange protein directly activated by cAMP1 (Epac1). In vivo, MR-409 mitigated cardiac hypertrophy in mice subjected to transverse aortic constriction and improved cardiac function. Moreover, CMs isolated from transverse aortic constriction mice treated with MR-409 showed improved contractility and reversal of sarcolemmal structure. Overall, these results identify GHRH as an antihypertrophic regulator, underlying its therapeutic potential for HF, and suggest possible beneficial use of its analogs for treatment of pathological cardiac hypertrophy.

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Abstract 1828: Dyxin/Lmcd1 Mediates Cardiac Hypertrophy Both In Vitro And In Vivo

Circulation ◽

10.1161/circ.118.suppl_18.s_393-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Derk Frank ◽

Robert Frauen ◽

Christiane Hanselmann ◽

Christian Kuhn ◽

Rainer Will ◽

...

Keyword(s):

Transgenic Mice ◽

Cardiac Hypertrophy ◽

Neonatal Rat ◽

Heart Weight ◽

Cardiomyocyte Hypertrophy ◽

The Novel ◽

Rat Cardiomyocytes ◽

A Genome

In order to identify new molecular mediators of cardiomyocyte hypertrophy, we performed a genome wide mRNA microarray screen of biomechanically stretched neonatal rat cardiomyocytes (NRCM). We found the novel sarcomeric LIM protein Dyxin/Lmcd1 being significantly upregulated (5.6x, p<0.001). Moreover, Dyxin was also significantly induced in several mouse models of myocardial hypertrophy including aortic banding, calcineurin overexpression and angiotensin stimulation, suggesting a potential role as a mediator of cardiac hypertrophy. To further test this hypothesis, we adenovirally overexpressed Dyxin in NRCM which potently induced cellular hypertrophy (150%, p<0.001) and the hypertrophic gene program (ANF, BNP). Consistent with an induction of calcineurin signalling, the calcineurin-responsive gene Rcan1– 4 (MCIP1.4) was found significantly upregulated (3.2x, p<0.001). Conversely, knockdown of Dyxin (−75% on protein level) via miRNA completely blunted the hypertrophic response to hypertrophic stimuli, including stretch and PE (both p<0.001). Furthermore, PE-mediated activation of calcineurin signaling (Upregulation of Rcan1– 4 by 7.3x, p<0.001) was completely blocked by knockdown of Dyxin. To confirm these results in vivo, we next generated transgenic mice with cardiac-restricted overexpression of Dyxin using the α -MHC promoter. Despite normal cardiac function as assessed by echocardiography, adult transgenic mice displayed significant cardiac hypertrophy in morphometrical analyses (3.9 vs. 3.5 mg/g LV/heart weight, n=8–11, p<0.05). This finding was supplemented by a robust induction of the hypertrophic gene program including ANF (3.7-fold, n=6, p=0.01) and α -skeletal actin (2.8-fold, n=6, p<0.05). Likewise, Rcan1– 4 was found upregulated (+112%, n=5, p<0.05), Taken together, we show that the novel sarcomeric z-disc protein Dyxin/Lmcd1 is significantly upregulated in several models of cardiac hypertrophy and potently induces cardiomyocyte hypertrophy both in vitro and in vivo. Mechanistically, Lmcd1/Dyxin appears to signal through the calcineurin pathway.

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Citri Reticulatae Pericarpium Alleviates Postmyocardial Infarction Heart Failure by Upregulating Pparγ Expression

10.21203/rs.3.rs-827017/v1 ◽

2021 ◽

Author(s):

Mengli Chen ◽

Hongyan Zhu ◽

Qingqing Zhu ◽

Xiaodong Wu ◽

Yufei Zhou ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Hypertrophy ◽

Molecular Mechanisms ◽

Systolic Function ◽

Tunel Staining ◽

Mouse Heart ◽

Coronary Artery Ligation ◽

Traditional Chinese Herbal Medicine

Abstract PurposeHeart failure after myocardial infarction (MI) is the leading cause of death worldwide. Citri Reticulatae Pericarpium (CRP) is a traditional Chinese herbal medicine that has been used in the clinic for centuries. In this study, we aimed to investigate the roles of CRP in cardiac remodeling and heart failure after MI, as well as the molecular mechanisms involved.MethodsMale C57BL/6 mice aged 8 weeks were subjected to coronary artery ligation to mimic the clinical situation in vivo. Echocardiography was used to assess the systolic function of the mouse heart. Masson trichrome staining and Wheat germ agglutinin (WGA) staining were utilized to determine the fibrotic area and cross-sectional area of the mouse heart, respectively. Cardiomyocytes and fibroblasts were isolated from neonatal rats aged 0–3 days in vitro using enzyme digestion. TUNEL staining and EdU staining were performed to evaluate apoptosis and proliferation, respectively. Gene expression changes were analyzed by qRT–PCR, and protein expression changes were assessed by Western blotting.ResultsOur findings revealed that CRP attenuated cardiac hypertrophy, fibrosis and apoptosis and alleviated heart failure after MI in vivo. Furthermore, CRP mitigated cardiomyocyte apoptosis and fibroblast proliferation and differentiation into myofibroblasts. In addition, the PPARγ inhibitor T0070907 completely abolished the abovementioned beneficial effects of CRP, and the PPARγ activator rosiglitazone failed to further ameliorate cardiac apoptosis and fibrosis in vitro.ConclusionCRP alleviates cardiac hypertrophy, fibrosis, and apoptosis and can ameliorate heart failure after MI via activation of PPARγ.

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Cullin-associated and neddylation-dissociated 1 protein (CAND1) governs cardiac hypertrophy and heart failure partially through regulating calcineurin degradation

10.21203/rs.3.rs-333521/v1 ◽

2021 ◽

Author(s):

Zhenwei Pan ◽

Xingda Li ◽

Yang Zhang ◽

Yue Zhao ◽

Yang Zhou ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Hypertrophy ◽

Protein Level ◽

Substrate Protein ◽

Pathological Cardiac Hypertrophy ◽

Promising Therapeutic Target ◽

Specific Proteins ◽

Related Proteins

Abstract Pathological cardiac hypertrophy is a process characterized by significant disturbance of protein turnover. Cullin-associated and Neddylation-dissociated 1 (CAND1) acts as a coordinator to modulate substrate protein degradation by promoting the formation of specific cullin-based ubiquitin ligase 3 complex in response to the accumulation of specific proteins, which thereby maintains the normal protein homeostasis. However, whether CAND1 titrates the degradation of hypertrophic related proteins and manipulates cardiac hypertrophy remains unknown. In this study, we found that the protein level of CAND1 was increased in the heart tissues from heart failure (HF) patients and TAC mice. CAND1-KO+/- aggravated TAC-induced cardiac hypertrophic phenotypes; in contrast, CAND1-Tg attenuated the maladaptive cardiac remodeling. At the protein level, CAND1 overexpression downregulated, whereas CAND1-KO+/- or knockdown upregulated the expression of calcineurin, a critical pro-hypertrophic protein at both in vivo and in vitro conditions. Mechanistically, CAND1 overexpression favored, whilst CAND1 knockdown blocked the assembly of Cul1/atrogin1/calcineurin complex, an E3 that renders the ubiquitination and degradation of calcineurin. It turned out that calcineurin ubiquitination was suppressed by CAND1 knockdown, but enhanced by CAND1 overexpression. In addition, overexpression of truncated calcineurin that cannot be recognized by atrogin1 abrogated the antihypertrophic effects of CAND1. Notably, CAND1 deficiency-induced hypertrophic phenotypes were partially rescued by knockdown of calcineurin, and application of exogenous CAND1 prevented TAC-induced cardiac hypertrophy and heart failure. In conclusion, CAND1 exerts a protective effect against cardiac hypertrophy and heart failure partially by inducing the degradation of calcineurin. CAND1 represents a novel, promising therapeutic target for cardiac hypertrophy and heart failure. Keywords: CAND1; heart failure; calcineurin; ubiquitination; cullin1

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Hispidulin Attenuates Cardiac Hypertrophy by Improving Mitochondrial Dysfunction

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2020.582890 ◽

2020 ◽

Vol 7 ◽

Author(s):

Yan Wang ◽

Zengshuo Xie ◽

Nan Jiang ◽

Zexuan Wu ◽

Ruicong Xue ◽

...

Keyword(s):

Oxidative Stress ◽

Heart Failure ◽

Cardiac Hypertrophy ◽

Mitochondrial Function ◽

Specific Inhibitor ◽

Cardiomyocyte Hypertrophy ◽

Mitochondrial Morphology ◽

Protective Effects

Cardiac hypertrophy is a pathophysiological response to harmful stimuli. The continued presence of cardiac hypertrophy will ultimately develop into heart failure. The mitochondrion is the primary organelle of energy production, and its dysfunction plays a crucial role in the progressive development of heart failure from cardiac hypertrophy. Hispidulin, a natural flavonoid, has been substantiated to improve energy metabolism and inhibit oxidative stress. However, how hispidulin regulates cardiac hypertrophy and its underlying mechanism remains unknown. We found that hispidulin significantly inhibited pressure overload-induced cardiac hypertrophy and improved cardiac function in vivo and blocked phenylephrine (PE)-induced cardiomyocyte hypertrophy in vitro. We further proved that hispidulin remarkably improved mitochondrial function, manifested by increased electron transport chain (ETC) subunits expression, elevated ATP production, increased oxygen consumption rates (OCR), normalized mitochondrial morphology, and reduced oxidative stress. Furthermore, we discovered that Sirt1, a well-recognized regulator of mitochondrial function, might be a target of hispidulin, as evidenced by its upregulation after hispidulin treatment. Cotreatment with EX527 (a Sirt1-specific inhibitor) and hispidulin nearly completely abolished the antihypertrophic and protective effects of hispidulin on mitochondrial function, providing further evidence that Sirt1 could be the pivotal downstream effector of hispidulin in regulating cardiac hypertrophy.

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Cardiomyocyte BRAF and type 1 RAF inhibitors promote cardiomyocyte and cardiac hypertrophy in mice in vivo

10.1101/2021.08.14.455637 ◽

2021 ◽

Author(s):

Angela Clerk ◽

Daniel N Meijles ◽

Michelle A Hardyman ◽

Stephen J Fuller ◽

Sonia P Chothani ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Hypertrophy ◽

Cardiomyocyte Hypertrophy ◽

Human Heart Failure ◽

Endogenous Gene ◽

Low Concentrations ◽

Extracellular Signal ◽

Experimental Type

The extracellular signal-regulated kinase 1/2 (ERK1/2) cascade promotes cardiomyocyte hypertrophy and is cardioprotective, with the three RAF kinases forming a node for signal integration. Our aims were to determine if BRAF is relevant for human heart failure, if BRAF promotes cardiomyocyte hypertrophy, and if Type 1 RAF inhibitors developed for cancer (that paradoxically activate ERK1/2 at low concentrations: the RAF paradox) may have the same effect. BRAF was upregulated in heart samples from patients with heart failure compared with normal controls. We assessed the effects of activated BRAF in the heart using mice with tamoxifen-activated Cre for cardiomyocyte-specific knock-in of the activating V600E mutation into the endogenous gene. We used echocardiography to measure cardiac dimensions/function. Cardiomyocyte BRAFV600E induced cardiac hypertrophy within 10 d, resulting in increased ejection fraction and fractional shortening over 6 weeks. This was associated with increased cardiomyocyte size without significant fibrosis, consistent with compensated hypertrophy. The experimental Type 1 RAF inhibitor, SB590885, and/or encorafenib (a RAF inhibitor used clinically) increased ERK1/2 phosphorylation in cardiomyocytes, and promoted hypertrophy, consistent with a RAF paradox effect. Both promoted cardiac hypertrophy in mouse hearts in vivo, with increased cardiomyocyte size and no overt fibrosis. In conclusion, BRAF potentially plays an important role in human failing hearts, activation of BRAF is sufficient to induce hypertrophy, and Type 1 RAF inhibitors promote hypertrophy via the RAF paradox. Cardiac hypertrophy resulting from these interventions was not associated with pathological features, suggesting that Type 1 RAF inhibitors may be useful to boost cardiomyocyte function.

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STING protects against cardiac dysfunction and remodelling by blocking autophagy

10.21203/rs.3.rs-154343/v2 ◽

2021 ◽

Author(s):

Rui Xiong ◽

Ning Li ◽

Wei Wang ◽

Bo Wang ◽

Wenyang Jiang ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Hypertrophy ◽

Cardiac Function ◽

Protein Expression ◽

Cardiac Fibroblasts ◽

Cardiac Remodelling ◽

Ang Ii ◽

Mrna And Protein Expression

Abstract Background Heart failure, which is characterized by cardiac remodelling, is one of the most common chronic diseases in the aged. Stimulator of interferon genes (STING) acts as an indispensable molecule modulating immune response and inflammation in many diseases. However, the effects of STING on cardiomyopathy, especially cardiac remodelling are still largely unknown. This study was designed to investigate whether STING could affect cardiac remodelling and to explore the potential mechanisms. Methods In vivo, aortic binding (AB) surgery was performed to construct the mice model of cardiac remodelling. A DNA microinjection system was used to trigger STING overexpression in mice. The STING mRNA and protein expression levels in mice heart were measured, and the cardiac hypertrophy, fibrosis, inflammation and cardiac function were also evaluated. In vitro, cardiomyocytes stimulated by Ang II and cardiac fibroblasts stimulated by TGF-β to performed to further study effects of STING on cardiac hypertrophy and fibroblast. In terms of mechanisms, the level of autophagy was detected in mice challenged with AB. Rapamycin, a canonical autophagy inducer, intraperitoneal injected into mice to study possible potential pathway. Results In vivo, the STING mRNA and protein expression levels in mice heart challenged with AB for 6 weeks were significantly increased. STING overexpression significantly mitigated cardiac hypertrophy, fibrosis and inflammation, apart from improving cardiac function. In vitro, experiments further disclosed that STING overexpression in cardiomyocytes induced by Ang II significantly inhibited the level of cardiomyocyte cross-section area and the ANP mRNA. Meanwhile, TGF-β-induced the increase of α-SMA content and collagen synthesis in cardiac fibroblasts could be also blocked by STING overexpression. In terms of mechanisms, mice challenged with AB showed higher level of autophagy compared with the normal mice. However, STING overexpression could reverse the activation of autophagy triggered by AB. Rapamycin, a canonical autophagy inducer, offset the cardioprotective effects of STING in mice challenged with AB. Finally, further experiments unveiled that STING may inhibit autophagy by phosphorylating ULK1 on serine757. Conclusions STING may prevent cardiac remodelling induced by pressure overload by inhibiting autophagy, which could be a promising therapeutic target in heart failure.

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LCZ696 Ameliorates Oxidative Stress and Pressure Overload-Induced Pathological Cardiac Remodeling by Regulating the Sirt3/MnSOD Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/9815039 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15

Author(s):

Shi Peng ◽

Xiao-feng Lu ◽

Yi-ding Qi ◽

Jing Li ◽

Juan Xu ◽

...

Keyword(s):

Oxidative Stress ◽

Heart Failure ◽

Cardiac Hypertrophy ◽

Pressure Overload ◽

Neonatal Rat ◽

Cardiomyocyte Hypertrophy ◽

Rat Cardiomyocytes ◽

Pathological Cardiac Hypertrophy

Aims. We aimed to investigate whether LCZ696 protects against pathological cardiac hypertrophy by regulating the Sirt3/MnSOD pathway. Methods. In vivo, we established a transverse aortic constriction animal model to establish pressure overload-induced heart failure. Subsequently, the mice were given LCZ696 by oral gavage for 4 weeks. After that, the mice underwent transthoracic echocardiography before they were sacrificed. In vitro, we introduced phenylephrine to prime neonatal rat cardiomyocytes and small-interfering RNA to knock down Sirt3 expression. Results. Pathological hypertrophic stimuli caused cardiac hypertrophy and fibrosis and reduced the expression levels of Sirt3 and MnSOD. LCZ696 alleviated the accumulation of oxidative reactive oxygen species (ROS) and cardiomyocyte apoptosis. Furthermore, Sirt3 deficiency abolished the protective effect of LCZ696 on cardiomyocyte hypertrophy, indicating that LCZ696 induced the upregulation of MnSOD and phosphorylation of AMPK through a Sirt3-dependent pathway. Conclusions. LCZ696 may mitigate myocardium oxidative stress and apoptosis in pressure overload-induced heart failure by regulating the Sirt3/MnSOD pathway.

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