Silencing of Hsa_circ_0055440 Alleviates Hypoxia-Induced Cardiomyocyte Injury by Regulating the MiR-499b-5p/ACSL1 Axis.

Circular RNAs (circRNAs) are a new type of regulatory RNAs, which are involved in various cardiac processes. However, the role of circRNA hsa_circ_0055440 (circ-USP39) in acute myocardial infarction regulation has not been studied yet.This study aims to explore the effect of circ-USP39 on hypoxia-induced cardiomyocyte injury.The head-to-tail splicing of circ-USP39 was verified by agarose gel electrophoresis. AC16 cell viability was detected using 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide assays. The apoptosis of the AC16 cell was determined by flow cytometry and detection of caspase-3 activity. The levels of creatine kinase-muscle/brain and cTnl were evaluated by specific detection kits. The interactions between miR-499b-5p and circ-USP39 (or acyl-CoA synthetase long-chain family member-1 (ACSL1) ) were verified by luciferase reporter assays.After confirming the circular characteristics of circ-USP39, we further found that the circ-USP39 expression was upregulated in hypoxia-induced cardiomyocytes and the circ-USP39 knockdown facilitated the viability of hypoxia-induced AC16, while suppressing cardiomyocyte apoptosis and injury. Importantly, circ-USP39 negatively regulated miR-499b-5p expression. As a downstream target of miR-499b-5p, ACSL1 partially counteracted the protective effect of circ-USP39 depletion on cardiomyocyte injury.Silencing of circ-USP39 alleviates hypoxia-induced cardiomyocyte injury via the miR-499b-5p/ACSL1 axis.

Corrigendum: Resveratrol Ameliorates Cardiac Remodeling in a Murine Model of Heart Failure With Preserved Ejection Fraction.

[This corrects the article DOI: 10.3389/fphar.2021.646240.].

Resveratrol Ameliorates Cardiac Remodeling in a Murine Model of Heart Failure With Preserved Ejection Fraction.

Objective: Accumulating evidence suggested that resveratrol (RES) could protect against adverse cardiac remodeling induced by several cardiovascular diseases. However, the role of RES in the setting of heart failure with preserved ejection fraction (HFpEF) and the underlying mechanisms of its action remain understood. This study was to determine whether RES could ameliorate HFpEF-induced cardiac remodeling and its mechanisms. Methods: In vivo, C57BL/6 mice served as either the sham or the HFpEF model. The HFpEF mice model was induced by uninephrectomy surgery and d-aldosterone infusion. RES (10 mg/kg/day, ig) or saline was administered to the mice for four weeks. In vitro, transforming growth factor ß1 (TGF-ß1) was used to stimulate neonatal rat cardiac fibroblasts (CFs) and Ex-527 was used to inhibit sirtuin 1 (Sirt1) in CFs. Echocardiography, hemodynamics, western blotting, quantitative real-time PCR, histological analysis, immunofluorescence, and ELISA kits were used to evaluate cardiac remodeling induced by HFpEF. Sirt1 and Smad3 expressions were measured to explore the underlying mechanisms of RES. Results: HFpEF mice developed left ventricular hypertrophy, preserved ejection fraction, diastolic dysfunction, and pulmonary congestion. Moreover, HFpEF mice showed increased infiltration of neutrophils and macrophages into the heart, including increased interleukin (IL)-1ß, IL-6, and TNF-α. We also observed elevated M1 macrophages and decreased M2 macrophages, which were exhibited by increased mRNA expression of M1 markers (iNOS, CD86, and CD80) and decreased mRNA expression of M2 markers (Arg1, CD163, and CD206) in HFpEF hearts. Moreover, HFpEF hearts showed increased levels of intracellular reactive oxygen species (ROS). Importantly, HFpEF mice depicted increased collagen-I and -III and TGF-ß mRNA expressions and decreased protein expression of phosphorylated endothelial nitric-oxide synthase (p-eNOS). Results of western blot revealed that the activated TGF-ß/Smad3 signaling pathway mediated HFpEF-induced cardiac remodeling. As expected, this HFpEF-induced cardiac remodeling was reversed when treated with RES. RES significantly decreased Smad3 acetylation and inhibited Smad3 transcriptional activity induced by HFpEF via activating Sirt1. Inhibited Sirt1 with Ex-527 increased Smad3 acetylation, enhanced Smad3 transcriptional activity, and offset the protective effect of RES on TGF-ß-induced cardiac fibroblast-myofibroblast transformation in CFs. Conclusion: Our results suggested that RES exerts a protective action against HFpEF-induced adverse cardiac remodeling by decreasing Smad3 acetylation and transcriptional activity via activating Sirt1. RES is expected to be a novel therapy option for HFpEF patients.

Androgen receptor regulates cardiac fibrosis in mice with experimental autoimmune myocarditis by increasing microRNA-125b expression.

Cardiac fibrosis is an important cardiac remodeling event in the development of inflammation dilated cardiomyopathy （iDCM）. We have previously observed that degradation enhancer of androgen receptor (ASC-J9®) could improve cardiac inflammation and fibrosis. Using Primary CFs, we demonstrated that ASC-J9® attenuates the expression of miR-125b, which subsequently inhibits the generation of collagen. In contrast, overexpressed AR in CFs induced collagen production, increases mir-125b.We also found that inhibition of miR-125b attenuates fibrosis which induced by the overexpression of AR. Our results indentify the functional role for AR as a regulator of cardiac fibrosis due to myocarditis and further show that AR exerts its effect by increasing microRNA-125b expression. Treatment with degradation enhancer of AR limits cardiac fibrosis in iDCM, thereby providing potentially a therapeutic approach for patients with iDCM.

Inhibition of microRNA­155 ameliorates cardiac fibrosis in the process of angiotensin II­induced cardiac remodeling.

Cardiac fibrosis triggered by pressure overload represents one of the major challenges in the treatment of cardiovascular diseases. MicroRNA (miRNA/miR)­155, a member of the small RNA family, has previously been demonstrated to be associated with cardiac inflammation. However, the effect of miR­155 on cardiac fibrosis induced by angiotensin II (Ang II), particularly in cardiac fibroblasts, requires further investigation. The present study aimed to investigate the effect of miR­155 in Ang II­induced cardiac fibrosis using animal models and cardiac fibroblasts. Animal models were established in male miR­155­/­ and wild­type (WT) C57Bl/6J mice (10­12 weeks old) by Ang II infusion using subcutaneously implanted minipumps. After 8 weeks of Ang II infusion, the results demonstrated that the deletion of miR­155 in mice markedly ameliorated ventricular remodeling compared with WT mice, as demonstrated by restricted inflammatory responses, decreased heart size, improved cardiac function and reduced myocardial fibrosis. In vitro, overexpression of miR­155 in cardiac fibroblasts led to significantly increased fibroblast to myofibroblast transformation. However, this effect was abrogated by miR­155 silencing. In conclusion, the results of the present study indicate that genetic loss of miR­155 in mice ameliorates cardiac fibrotic remodeling following pressure overload. Therefore, inhibiting miR­155 may have potential as an adjunct to reduce cardiac inflammation in the treatment of cardiac fibrosis.

Targeting androgen receptor with ASC-J9 attenuates cardiac injury and dysfunction in experimental autoimmune myocarditis by reducing M1-like macrophage.

BACKGROUD: Macrophages are important mediators in inflammatory cardiovascular diseases. Experimental autoimmune myocarditis (EAM) is characterized by pronounced macrophages infiltration, cardiac necrosis and cardiac fibrosis. Androgen receptor (AR) is a regulator of immune system which can control macrophages' infiltration and function in various inflammatory-related diseases. However, the effect of AR on the inflammatory response in EAM is unknown. Our study aims to investigate the potential role of AR on the development of autoimmune myocarditis. METHODS AND RESULTS: In our study, we found that AR was increased in the myocardium and was associated with the time-course of EAM progression, which motivated us to use ASC-J9 (an enhancer of AR degradation). The results revealed that ASC-J9 administration in EAM mice resulted in an attenuation in the severity of disease and cardiac injury, a reduced CD4+T cell response, reduced monocyte/macrophage infiltration, and decreases in the pro-inflammatory cytokines. Furthermore, ASC-J9 was also found to prevent Raw264.7 cells polarization to M1 macrophages in response to LPS by upregulating suppressor of cytokine signaling 1(SOCS1) and downregulating signal transducer and activator of the transcription 5(STAT5) activity. CONCLUSIONS: AR facilitated EAM development, and targeting AR with ASC-J9 attenuated cardiac injury and dysfunction by inhibiting macrophages polarization towards M1 macrophages.

Effects of 1, 25-Dihydroxyvitamin D3 on Experimental Autoimmune Myocarditis in Mice.

BACKGROUND/AIMS: Myocarditis is an important inflammatory disease of the heart which causes life-threatening conditions. 1, 25(OH)2 D3 has effects on multiple systems and diseases. The present study was aimed to investigate the effect of 1, 25(OH)2 D3 on experimental autoimmune myocarditis (EAM), and explored the underlying mechanisms involved. METHODS: EAM was induced by immunizing BALB/c mice with cardiac α-myosin heavy chain peptides (MyHC-α). 1, 25(OH)2 D3 (1,000 ng/kg once) or vehicle was administered intraperitoneally every other day during the entire experiment. On day 21, transthoracic echocardiography was performed and cardiac inflammatory infiltration was detected by hematoxylin and eosin (HE). The terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay, and Western blots for the expression of protein caspase-3 and cleaved-caspase3 were used to evaluate apoptosis. Transmission electron microscopy and Western blots for the expression of protein Beclin-1, LC3B, and P62 were used to evaluate autophagy. RESULTS: The ratio of heart weight/body weight was significantly reduced in 1, 25(OH)2 D3 -treated EAM mice, compared with vehicle -treated ones. 1, 25(OH)2 D3 treatment improved cardiac function, diminished cell infiltration in cardiac, suppressed myocardial apoptosis, decreased the number of autophagosomes, and decreased the protein expression of Beclin-1, LC3-II and p62. CONCLUSIONS: The present results demonstrated that administration of 1, 25(OH)2 D3 decreased EAM severity. 1, 25(OH)2 D3 treatment may be a feasible therapeutic approach for EAM.

The Associations Between the Polymorphisms of Vitamin D Receptor and Coronary Artery Disease: A Systematic Review and Meta-Analysis.

Vitamin D receptor (VDR) polymorphisms were indicated to be associated with coronary artery disease (CAD); however, published studies reported inconsistent results.The aim of this meta-analysis is to reach a more accurate estimation of the relationship between VDR genetic polymorphisms and CAD risk.Eligible studies were retrieved by searching PubMed, Embase, VIP, Wanfang and China National Knowledge Infrastructure databases. Included and excluded criteria were formulated. The case group was patients with CAD, and the control group was healthy subjects. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate VDR polymorphisms associations with CAD risk. Heterogeneity was evaluated by Q statistic and I statistic.Seven studies of a total of 2306 CAD patients and 4151 control subjects met the inclusion criteria. The pooled results from Taq1 showed increased risk in allelic model (OR = 1.14, 95% CI = 1.02-1.28), dominant model (OR = 1.21, 95% CI = 1.02-1.43), heterozygote model (OR = 1.19, 95% CI = 1.00-1.1.42), and homozygote model (OR = 1.27, 95% CI = 1.01-1.61). Besides, Fok1 T > C showed decreased risk in allelic model (OR = 0.81, 95% CI = 0.65-1.00) and Fok1 A > G also showed decreased risk in allelic model (OR = 0.67, 95% CI = 0.45-1.00) and recessive model (OR = 0.55, 95% CI = 0.31-0.97). In Caucasian subgroup, Bsm1showed increased risk in allelic model (OR = 1.23, 95% CI = 1.02-1.47), heterozygote model (OR = 1.20, 95% CI = 1.00-1.44), and homozygote model (OR = 1.22, 95% CI = 1.02-1.45). In CAD patients with type 2 diabetes mellitus (T2DM), Apa1showed a decreased risk in heterozygote model (OR = 0.80, 95% CI = 0.66-0.98); however, increased risk in recessive model (OR = 5.00, 95% CI = 2.74-9.13) was discovered in CAD patients without T2DM.The Fok1 polymorphism may play a protective role in CAD, and the possible protective role in Apa1 CA genotype in CAD patients with T2DM needs further studies. The Taq1 polymorphism is found to be associated with a significant increase in CAD risk based on our analysis; moreover, increased risk in Apa1 polymorphism in CAD patients without T2DM and Bsm1 polymorphism in Caucasian group is also detected.

Inhibition of microRNA-155 ameliorates experimental autoimmune myocarditis by modulating Th17/Treg immune response.

UNLABELLED: Experimental autoimmune myocarditis (EAM) is an inflammatory cardiac disease driven by autoantigen-specific CD4+ T cells. Th17 and Treg cells are crucial participants in immune response. A wide variety of immune disorders are associated with Th17/Treg imbalance. MicroRNA-155 (miR-155) is a pivotal regulator of the immune system. However, the modulatory effect of miR-155 on Th17/Treg immune response during EAM is unknown. Our study aims to investigate the potential role of miR-155 on the development of autoimmune myocarditis. In this study, we revealed that miR-155 expression was highly elevated in heart tissue and CD4+ T cells during EAM. Also, we identified a proliferative and functional imbalance of Th17/Treg in EAM, which is due to a more active development of Th17 cells and an increased resistance of Th17 cells to Treg-mediated suppression. MiR-155 inhibition in EAM resulted in attenuated severity of disease and cardiac injury, reduced Th17 immune response, and decreased dendritic cell (DC) function of secreting Th17-polarizing cytokines. Furthermore, CD4+ T cells from miR-155-inhibited EAM mice exhibited reduced proliferation and IL-17A secretion in response to autoantigen. Finally, we confirmed an indispensable positive role of miR-155 on the differentiation of Th17 cells and the DC function of secreting Th17-polarizing cytokines through in vitro studies. These findings demonstrated that miR-155 adversely promotes EAM by driving a Th17/Treg imbalance in favor of Th17 cells, and anti-miR-155 treatment can significantly reduce the autoimmune response thus to ameliorate EAM, suggesting that miR-155 inhibition could be a promising therapeutic strategy for the treatment of autoimmune myocarditis. KEY MESSAGE: MiR-155 expression was highly elevated in EAM mice. An imbalance of Th17/Treg existed in EAM mice. MiR-155 inhibition in EAM attenuated disease severity and cardiac injury. MiR-155 inhibition suppressed Th17 immune response in EAM. MiR-155 inhibition reduced DC function of secreting Th17-polarizing cytokines in EAM.

microRNA-21 promotes cardiac fibrosis and development of heart failure with preserved left ventricular ejection fraction by up-regulating Bcl-2.

The morbidity and mortality of heart failure with preserved left ventricular ejection fraction (HFpEF) were similar to those of systolic heart failure, but the pathogenesis of HFpEF remains poorly understood. It was demonstrated that, in systolic heart failure, microRNA-21 (miR-21) could inhibit the apoptosis of cardiac fibroblasts, leading to cardiac hypertrophy and myocardial fibrosis, but the role of miR-21 in HFpEF remains unknown. By employing cell culture technique, rat myocardiocytes and cardiac fibroblasts were obtained. The expression of miR-21 in the two cell types under different conditions was compared and we found that the miR-21 expression was significantly higher in cardiac fibroblasts than in myocardiocytes. We established a rat HFpEF model and harvested the tissues of cardiac apex for pathological examination, Northern blotting and so forth. We found that miR-21 expression was significantly higher in model rats than in sham-operated rats, and the model rats developed the cardiac atrophy and cardiac fibrosis. After injection of miR-21 antagonist, the the cardiac atrophy and cardiac fibrosis were conspicuously ameliorated. Both in vivo and in vitro, inhibition of miR-21 expression resulted in reduced Bcl-2 expression while over-expression of miR-21 led to elevation of Bcl-2 expression. Our study suggested that miR-21 promoted the development of HFpEF by up-regulating the expression of anti-apoptotic gene Bcl-2 and thereby suppressing the apoptosis of cardiac fibrosis.