G3bp1 – microRNA-1 axis regulates cardiomyocyte hypertrophy

AbstractTelocytes are interstitial cells with long, thin processes by which they contact each other and form a network in the interstitium. Myocardial remodeling of adult patients with different forms of atrial fibrillation (AF) occurs with an increase in fibrosis, age-related isolated atrial amyloidosis (IAA), cardiomyocyte hypertrophy and myolysis. This study aimed to determine the ultrastructural and immunohistochemical features of cardiac telocytes in patients with AF and AF + IAA. IAA associated with accumulation of atrial natriuretic factor was detected in 4.3–25% biopsies of left (LAA) and 21.7–41.7% of right (RAA) atrial appendage myocardium. Telocytes were identified at ultrastructural level more often in AF + IAA, than in AF group and correlated with AF duration and mitral valve regurgitation. Telocytes had ultrastructural signs of synthetic, proliferative, and phagocytic activity. Telocytes corresponded to CD117+, vimentin+, CD34+, CD44+, CD68+, CD16+, S100-, CD105- immunophenotype. No significant differences in telocytes morphology and immunophenotype were found in patients with various forms of AF. CD68-positive cells were detected more often in AF + IAA than AF group. We assume that in aged AF + IAA patients remodeling of atrial myocardium provoked transformation of telocytes into “transitional forms” combining the morphological and immunohistochemical features with signs of fibroblast-, histiocyte- and endotheliocyte-like cells.

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Testosterone activates glucose metabolism through AMPK and androgen signaling in cardiomyocyte hypertrophy

Biological Research ◽

10.1186/s40659-021-00328-4 ◽

2021 ◽

Vol 54 (1) ◽

Author(s):

Mayarling Francisca Troncoso ◽

Mario Pavez ◽

Carlos Wilson ◽

Daniel Lagos ◽

Javier Duran ◽

...

Keyword(s):

Glucose Metabolism ◽

Cardiac Hypertrophy ◽

Glucose Uptake ◽

Male Rats ◽

Cardiomyocyte Hypertrophy ◽

Mrna Levels ◽

Elevated Glucose ◽

Amp Activated Protein Kinase ◽

Cultured Cardiomyocytes

Abstract Background Testosterone regulates nutrient and energy balance to maintain protein synthesis and metabolism in cardiomyocytes, but supraphysiological concentrations induce cardiac hypertrophy. Previously, we determined that testosterone increased glucose uptake—via AMP-activated protein kinase (AMPK)—after acute treatment in cardiomyocytes. However, whether elevated glucose uptake is involved in long-term changes of glucose metabolism or is required during cardiomyocyte growth remained unknown. In this study, we hypothesized that glucose uptake and glycolysis increase in testosterone-treated cardiomyocytes through AMPK and androgen receptor (AR). Methods Cultured cardiomyocytes were stimulated with 100 nM testosterone for 24 h, and hypertrophy was verified by increased cell size and mRNA levels of β-myosin heavy chain (β-mhc). Glucose uptake was assessed by 2-NBDG. Glycolysis and glycolytic capacity were determined by measuring extracellular acidification rate (ECAR). Results Testosterone induced cardiomyocyte hypertrophy that was accompanied by increased glucose uptake, glycolysis enhancement and upregulated mRNA expression of hexokinase 2. In addition, testosterone increased AMPK phosphorylation (Thr172), while inhibition of both AMPK and AR blocked glycolysis and cardiomyocyte hypertrophy induced by testosterone. Moreover, testosterone supplementation in adult male rats by 5 weeks induced cardiac hypertrophy and upregulated β-mhc, Hk2 and Pfk2 mRNA levels. Conclusion These results indicate that testosterone stimulates glucose metabolism by activation of AMPK and AR signaling which are critical to induce cardiomyocyte hypertrophy.

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KLK11 promotes the activation of mTOR and protein synthesis to facilitate cardiac hypertrophy

BMC Cardiovascular Disorders ◽

10.1186/s12872-021-02053-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Yi Wang ◽

Hongjuan Liao ◽

Yueheng Wang ◽

Jinlin Zhou ◽

Feng Wang ◽

...

Keyword(s):

Protein Synthesis ◽

Angiotensin Ii ◽

Cardiac Hypertrophy ◽

Western Blot ◽

Real Time ◽

Real Time Pcr ◽

Mtor Signaling ◽

Heart Weight ◽

Cardiomyocyte Hypertrophy ◽

Quantitative Real Time Pcr

Abstract Background Cardiovascular diseases have become the leading cause of death worldwide, and cardiac hypertrophy is the core mechanism underlying cardiac defect and heart failure. However, the underlying mechanisms of cardiac hypertrophy are not fully understood. Here we investigated the roles of Kallikrein 11 (KLK11) in cardiac hypertrophy. Methods Human and mouse hypertrophic heart tissues were used to determine the expression of KLK11 with quantitative real-time PCR and western blot. Mouse cardiac hypertrophy was induced by transverse aortic constriction (TAC), and cardiomyocyte hypertrophy was induced by angiotensin II. Cardiac function was analyzed by echocardiography. The signaling pathway was analyzed by western blot. Protein synthesis was monitored by the incorporation of [3H]-leucine. Gene expression was analyzed by quantitative real-time PCR. Results The mRNA and protein levels of KLK11 were upregulated in human hypertrophic hearts. We also induced cardiac hypertrophy in mice and observed the upregulation of KLK11 in hypertrophic hearts. Our in vitro experiments demonstrated that KLK11 overexpression promoted whereas KLK11 knockdown repressed cardiomyocytes hypertrophy induced by angiotensin II, as evidenced by cardiomyocyte size and the expression of hypertrophy-related fetal genes. Besides, we knocked down KLK11 expression in mouse hearts with adeno-associated virus 9. Knockdown of KLK11 in mouse hearts inhibited TAC-induced decline in fraction shortening and ejection fraction, reduced the increase in heart weight, cardiomyocyte size, and expression of hypertrophic fetal genes. We also observed that KLK11 promoted protein synthesis, the key feature of cardiomyocyte hypertrophy, by regulating the pivotal machines S6K1 and 4EBP1. Mechanism study demonstrated that KLK11 promoted the activation of AKT-mTOR signaling to promote S6K1 and 4EBP1 pathway and protein synthesis. Repression of mTOR with rapamycin blocked the effects of KLK11 on S6K1 and 4EBP1 as well as protein synthesis. Besides, rapamycin treatment blocked the roles of KLK11 in the regulation of cardiomyocyte hypertrophy. Conclusions Our findings demonstrated that KLK11 promoted cardiomyocyte hypertrophy by activating AKT-mTOR signaling to promote protein synthesis.

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Protective action of the microbial metabolite butyrate against cardiomyocyte hypertrophy

European Heart Journal ◽

10.1093/ehjci/ehaa946.3666 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

M Umei ◽

H Akazawa ◽

A Saga-Kamo ◽

H Yagi ◽

Q Liu ◽

...

Keyword(s):

Heart Failure ◽

Short Chain Fatty Acid ◽

Short Chain Fatty Acids ◽

Chain Fatty Acid ◽

G Protein Coupled Receptors ◽

Short Chain ◽

Cardiomyocyte Hypertrophy ◽

Cell Transcriptome ◽

Single Cell Transcriptome ◽

G Protein Coupled

Abstract Introduction Short-chain fatty acids are one of the gut microbial metabolites that may influence host physiology. We previously reported that gut dysbiosis was associated with heart failure, and that the proportions of butyrate-producing bacteria diminished prominently in the gut of patients with heart failure. Purpose We investigated the molecular mechanism of butyrate and investigated the protective mechanism against heart failure. Methods We searched for G protein-coupled receptors for short-chain fatty acids using single-cell transcriptome analysis of cardiomyocytes and non-cardiomyocytes isolated from murine hearts. In addition, we examined the effects of butyrate on endothelin-1 (ET1) or isoproterenol-induced hypertrophic responses and histone deacetylase (HDAC) activities in cultured neonatal rat cardiomyocytes. Results Single-cell transcriptome analysis and co-expression network analysis revealed that G protein-coupled receptors for short-chain fatty acid receptors were not expressed in cardiomyocytes and that Olfr78 was expressed in vascular smooth muscle cells in the heart. Treatment with butyrate inhibited ET1-induced hypertrophic growth and up-regulation of the genes such as Nppa, Acta1, and Myh7 in cultured rat neonatal cardiomyocytes. Moreover, butyrate increased the acetylation levels of histone H3, indicating that butyrate has an inhibitory effect on HDAC in cardiomyocytes. In addition, treatment with butyrate caused up-regulation of Inpp5f, encoding inositol polyphosphate-5-phosphatase f, which was associated with a significant decrease in the phosphorylation levels of Akt. These results suggest that butyrate may act as HDAC inhibitor to increase Inpp5f gene expression, leading to the activation of Akt-glycogen synthase kinase 3beta (Gsk3beta) pathway, and thereby protect against hypertrophic responses. Conclusion There was no known GPCR for short-chain fatty acid expressed in cardiomyocytes. However, butyrate suppressed cardiomyocyte hypertrophy through epigenetic modification of gene expression. Our results may uncover a potential role of the dysbiosis of intestinal microbiota in the pathogenesis of cardiac hypertrophy and failure. Funding Acknowledgement Type of funding source: None

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Betulinic Acid Protects DOX-Triggered Cardiomyocyte Hypertrophy Response through the GATA-4/Calcineurin/NFAT Pathway

Molecules ◽

10.3390/molecules26010053 ◽

2020 ◽

Vol 26 (1) ◽

pp. 53

Author(s):

Jung Joo Yoon ◽

Chan Ok Son ◽

Hye Yoom Kim ◽

Byung Hyuk Han ◽

Yun Jung Lee ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Hypertrophy ◽

Natriuretic Peptide ◽

Betulinic Acid ◽

Cardiomyocyte Hypertrophy ◽

Ros Generation ◽

H9c2 Cells ◽

Myosin Light Chain 2 ◽

Cardiovascular Morbidity And Mortality

Cardiac hypertrophy is a major risk factor for heart failure and leads to cardiovascular morbidity and mortality. Doxorubicin (DOX) is regarded as one of the most potent anthracycline antibiotic agents; however, its clinical usage has some limitations because it has serious cardiotoxic side effects such as dilated cardiomyopathy and congestive heart failure. Betulinic acid (BA) is a pentacyclic-cyclic lupane-type triterpene that has been reported to have anti-bacterial, anti-inflammatory, anti-vascular neogenesis, and anti-fibrotic effects. However, there is no study about its direct effect on DOX induced cardiac hypertrophy and apoptosis. The present study aims to investigate the effect of BA on DOX-induced cardiomyocyte hypertrophy and apoptosis in vitro in H9c2 cells. The H9c2 cells were stimulated with DOX (1 µM) in the presence or absence of BA (0.1–1 μM) and incubated for 24 h. The results of the present study indicated that DOX induces the increase cell surface area and the upregulation of hypertrophy markers including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), beta-myosin heavy chain (β-MHC), and Myosin Light Chain-2 (MLC2) in H9c2 cells. However, the pathological hypertrophic responses were downregulated after BA treatment. Moreover, phosphorylation of JNK, ERK, and p38 in DOX treated H9c2 cells was blocked by BA. As a result of measuring the change in ROS generation using DCF-DA, BA significantly inhibited DOX-induced the production of intracellular reactive oxygen species (ROS) when BA was treated at a concentration of over 0.1 µM. DOX-induced activation of GATA-4 and calcineurin/NFAT-3 signaling pathway were remarkably improved by pre-treating of BA to H9c2 cells. In addition, BA treatment significantly reduced DOX-induced cell apoptosis and protein expression levels of Bax and cleaved caspase-3/-9, while the expression of Bcl-2 was increased by BA. Therefore, BA can be a potential treatment for cardiomyocyte hypertrophy and apoptosis that lead to sudden heart failure.

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Hypertrophy-Reduced Autophagy Causes Cardiac Dysfunction by Directly Impacting Cardiomyocyte Contractility

Cells ◽

10.3390/cells10040805 ◽

2021 ◽

Vol 10 (4) ◽

pp. 805

Author(s):

Christiane Ott ◽

Tobias Jung ◽

Sarah Brix ◽

Cathleen John ◽

Iris R. Betz ◽

...

Keyword(s):

Cardiomyocyte Hypertrophy ◽

Aortic Constriction ◽

Cell Contractility ◽

Neonatal Cardiomyocytes ◽

Cardiomyocyte Contractility ◽

Cardioprotective Effects ◽

Modified Proteins ◽

Cardiomyocyte Autophagy

Cardiac remodeling and contractile dysfunction are leading causes in hypertrophy-associated heart failure (HF), increasing with a population’s rising age. A hallmark of aged and diseased hearts is the accumulation of modified proteins caused by an impaired autophagy-lysosomal-pathway. Although, autophagy inducer rapamycin has been described to exert cardioprotective effects, it remains to be shown whether these effects can be attributed to improved cardiomyocyte autophagy and contractility. In vivo hypertrophy was induced by transverse aortic constriction (TAC), with mice receiving daily rapamycin injections beginning six weeks after surgery for four weeks. Echocardiographic analysis demonstrated TAC-induced HF and protein analyses showed abundance of modified proteins in TAC-hearts after 10 weeks, both reduced by rapamycin. In vitro, cardiomyocyte hypertrophy was mimicked by endothelin 1 (ET-1) and autophagy manipulated by silencing Atg5 in neonatal cardiomyocytes. ET-1 and siAtg5 decreased Atg5–Atg12 and LC3-II, increased natriuretic peptides, and decreased amplitude and early phase of contraction in cardiomyocytes, the latter two evaluated using ImageJ macro Myocyter recently developed by us. ET-1 further decreased cell contractility in control but not in siAtg5 cells. In conclusion, ET-1 decreased autophagy and cardiomyocyte contractility, in line with siAtg5-treated cells and the results of TAC-mice demonstrating a crucial role for autophagy in cardiomyocyte contractility and cardiac performance.

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