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Venous thromboembolic complications (VTCs), which include deep vein thrombosis (DVT) and pulmonary embolism (PE), have remained a pressing problem in modern clinical medicine for a long time. Despite the already wide arsenal of modern methods for diagnosing and treating this disease, VTCs rank third in the structure of causes of death among all cardiovascular diseases, behind myocardial infarction (MI) and ischemic stroke (IS). Numerous studies have confirmed the importance of understanding the molecular processes of VTCs for effective therapy and diagnosis. Significant progress has been made in VTC research in recent years, where the relative contribution of microRNAs (miRNAs) in the mechanism of thrombus formation and their consideration as therapeutic targets have been well studied. In this case, accurate, timely, and as early as possible diagnosis of VTCs is of particular importance, which will help improve both short-term and long-term prognoses of patients. This case accounts for the already well-studied circulating miRNAs as non-invasive biomarkers. This study presents currently available literature data on the role of miRNAs in VTCs, revealing their potential as therapeutic targets and diagnostic and prognostic tools for this terrible disease. [ABSTRACT FROM AUTHOR]

Background/Aims: Deregulated myocardial fibrosis is associated with a wide spectrum of cardiac conditions, being considered one of the major causes for heart disease. Our study was designed to investigate the role of microRNA-328 (miR-328) in regulating cardiac fibrosis. Methods: We induced cardiac fibrosis following MI by occlusion of the left coronary artery in C57BL/6 mice. Real-time PCR was employed to evaluate the level of miR-328. Masson’s Trichrome stain was used to evaluate the development of fibrosis. Luciferase activity assay was performed to confirm the miRNA’s binding site in the TGFβRIII gene. Western blot analysis was used to examine TGFβRIII, p-smad2/3 and TGF-β1 at protein level. Results: In this study, we found that miR-328 was significantly upregulated in the border zone of infarcted myocardium of wild type (WT) mice; TGFβRIII was downregulated whereas TGF-β1 was upregulated along with increased cardiac fibrosis. And miR-328 stimulated TGF-β1 signaling and promoted collagen production in cultured fibroblasts. We further found that the pro-fibrotic effect of miR-328 was mediated by targeting TGFβRIII. Additionally, cardiac fibrosis was significantly reduced in infarcted heart when treated with miR-328 antisense. Conclusions: These data suggest that miR-328 is a potent pro-fibrotic miRNA and an important determinant of cardiac fibrosis in diseased heart. [ABSTRACT FROM AUTHOR]

Background/Aims: Acute myocardial infarction (AMI) is a devastating cardiovascular disease with a high rate of morbidity and mortality, partly due to enhanced arrhythmogenicity. MicroRNAs (miRNAs) have been shown to participate in the regulation of cardiac ion channels and the associated arrhythmias. The purpose of this study was to test our hypothesis that miR-223-3p contributes to the electrical disorders in AMI via modulating KCND2, the gene encoding voltage-gated channel Kv4.2 that carries transient outward K+ current Ito. Methods: AMI model was established in male Sprague-Dawley (SD) rats by left anterior descending artery (LAD) ligation. Evans blue and TTC staining was used to measure infarct area. Ito was recorded in isolated ventricular cardiomyocytes or cultured neonatal rat ventricular cells (NRVCs) by whole-cell patch-clamp techniques. Western blot analysis was employed to detect the protein level of Kv4.2 and real-time RT-PCR to determine the transcript level of miR-223- 3p. Luciferase assay was used to examine the interaction between miR-223-3p and KCND2 in cultured NRVCs. Results: Expression of miR-223-3p was remarkably upregulated in AMI relative to sham control rats. On the contrary, the protein level of Kv4.2 and Ito density were significantly decreased in AMI. Consistently, transfection of miR-223-3p mimic markedly reduced Kv4.2 protein level and Ito current in cultured NRVCs. Co-transfection of AMO-223-3p (an antisense inhibitor of miR-223-3p) reversed the repressive effect of miR-223-3p. Luciferase assay showed that miR-223-3p, but not the negative control, substantially suppressed the luciferase activity, confirming the direct binding of miR-223-3p to the seed site within the KCND2 sequence. Finally, direct intramuscular injection of AMO-223-3p into the ischemic myocardium to knockdown endogenous miR-223-3p decreased the propensity of ischemic arrhythmias. Conclusions: Upregulation of miR-223-3p in AMI repressed the expression of KCND2/Kv4.2 resulting in reduction of Ito density that can cause APD prolongation and promote arrhythmias in AMI, and therefore knockdown of endogenous miR-223-3p might be considered a new approach for antiarrhythmic therapy of ischemic arrhythmias. [ABSTRACT FROM AUTHOR]

Background: Several studies have confirmed the role of microRNAs in regulating ischemia/reperfusion-induced cardiac injury (I/R-I). MiR-17-5p has been regarded as an oncomiR in the development of cancer. However, its potential role in cardiomyocytes has not been exploited. The aim of this study is to investigate the role of miR-17-5p in I/R-I and the underlying mechanism through targeting Stat3, a key surviving factor in cardiomyocytes. Methods: MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide) assay was used to detect the cell viability. ELISA and TUNEL were performed to measure apoptosis of neonatal rat ventricular cardiomyocytes (NRVCs). Infarct area was estimated by TTC (triphenyltetrazolium chloride) and Evans blue staining. Western blot analysis was employed to detect the Stat3 and p-Stat3 levels and real-time RT-PCR was used to quantify miR-17-5p level. Results: The miR-17-5p level was significantly up-regulated in I/R-I mice and in NRVCs under oxidative stress. Overexpression of miR-17-5p aggravated cardiomyocyte injury with reduced cell viability and enhanced apoptotic cell death induced by H2O2, whereas inhibition of miR-17-5p by its antisense AMO-17-5p abrogated the deleterious changes. Moreover, the locked nucleic acid-modified antisense (LNA-anti-miR-17-5p) markedly decreased the infarct area and apoptosis induced by I/R-I in mice. Furthermore, overexpression of miR-17-5p diminished the p-Stat3 level in response to H2O2. The results from Western blot analysis and luciferase reporter gene assay confirmed Stat3 as a target gene for miR-17-5p. Conclusion: Upregulation of miR-17-5p promotes apoptosis induced by oxidative stress via targeting Stat3, accounting partially for I/R-I. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Estrogen deficiency is associated with increased incidence of cardiovascular diseases. But merely estrogen supplementary treatment can induce many severe complications such as breast cancer. The present study was designed to elucidate molecular mechanisms underlying increased susceptibility of arrhythmogenesis during myocardial infarction with estrogen deprivation, which provides us a new target to cure cardiac disease accompanied with estrogen deprivation. We successfully established a rat model of myocardial ischemia (MI) accompanied with estrogen deprivation by coronary artery ligation and ovariectomy (OVX). Vulnerability and mortality of ventricular arrhythmias increased in estrogen deficiency rats compared to non estrogen deficiency rats when suffered MI, which was associated with down-regulation of microRNA-151-5p (miR-151-5p). Luciferase Reporter Assay demonstrated that miR-151-5p can bind to the 3′-UTR of FXYD1 (coding gene of phospholemman, PLM) and inhibit its expression. We found that the expression of PLM was increased in (OVX+MI) group compared with MI group. More changes such as down-regulation of Kir2.1/IK1, calcium overload had emerged in (OVX+MI) group compared to MI group merely. Transfection of miR-151-5p into primary cultured myocytes decreased PLM levels and [Ca2+]i, however, increased Kir2.1 levels. These effects were abolished by the antisense oligonucleotides against miR-151-5p. Co-immunoprecipitation and immunofluorescent experiments confirmed the co-localization between Kir2.1 and PLM in rat ventricular tissue. We conclude that the increased ventricular arrhythmias vulnerability in response to acute myocardial ischemia in rat is critically dependent upon down-regulation of miR-151-5p. These findings support the proposal that miR-151-5p could be a potential therapeutic target for the prevention of ischemic arrhythmias in the subjects with estrogen deficiency. [ABSTRACT FROM AUTHOR]

Abstract: Cardiac hypertrophy is a primary predictor of progressive heart disease that often results in heart failure. Growing evidence has demonstrated that microRNAs (miRNAs) play a critical role in regulating cardiac hypertrophy. This study was designed to evaluate the effect of miR-328 on cardiac hypertrophy and the potential molecular mechanisms. We found that transgenic overexpression of miR-328 in the heart induced cardiac hypertrophy in mice, which was accompanied by reduced SERCA2a level increased intracellular calcium concentration and calcineurin protein level, and enhanced NFATc3 nuclear translocation. However, normalization of miR-328 level by its antisense chemically modified with locked nucleic acid (LNA-antimiR-328) reversed the changes. Forced expression of miR-328 resulted in cardiomyocyte hypertrophy in cultured neonatal rat ventricular cells, which was accompanied by downregulation of SERCA2a expression and activation of the calcineurin/NFATc3 signaling pathway. These changes were abolished by LNA-antimiR-328. We validated the SERCA2a as a direct target for miR-328. MiR-328 expression was upregulated in cardiomyocyte treated with isoproterenol (ISO) to induce hypertrophy; while knockdown of miR-328 attenuated the hypertrophic responses. The level of miR-328 was significantly elevated in a mouse model of hypertrophy by thoracic aortic banding (TAC). Consistently, SERCA2a was downregulated, whereas calcineurin were upregulated, and NFATc3 nuclear translocation was enhanced. In contrast, hypertrophy in these mice was significantly alleviated when treated with miR-328 antisense. MiR-328 promotes cardiac hypertrophy by targeting SERCA2a. Our study therefore uncovered a novel molecular mechanism for cardiac hypertrophy and indicated miR-328 as a potential therapeutic target for this cardiac condition. [Copyright &y& Elsevier]