Overexpression of microRNA-133a inhibits ischemia-reperfusion-induced cardiomyocyte apoptosis by targeting DAPK2

Abstract

To examine microRNA-133a (miR-133a) endogenous expression in cardiomyocytes after ischemia-reperfusion (I/R) injury and study the effects of miR-133a overexpression on I/R injury-induced cardiomyocyte apoptosis. Dual-Luciferase Reporter Assay detected dynamic expression of miR-133a. In an in vitro hypoxia-reoxygenation (HR) injury model and an in vivo rat model of I/R injury, rat cardiomyocytes were transfected with miR-133a mimic to test the effects of miR-133a overexpression on apoptosis. MiR-133a and Death Associated Protein Kinase 2 (DAPK2) mRNA expression was measured using real-time-PCR, and DAPK2 protein expression was detected by western blotting. Annexin V-fluorescein isothiocyanate/propidium iodide (PI) double-staining measured the apoptosis rate in H9C2 cells and transferase dUTP nick end labeling assay quantified the cardiomyocyte apoptosis rate in tissues obtained from in vivo the rat model. DAPK2 is a target of miR-133a. Both in vitro and in vivo results confirmed that after expression of miR-133a mimics, miR-133a levels increased, which was accompanied by decrease in DAPK2 mRNA and protein expression. In H9C2 cells, HR injury caused a sharp decrease in miR-133a expression and a significant upregualtion of DAPK2 mRNA and protein levels. However, exogenous miR-133a expression led to a significant reduction in DAPK2 mRNA and protein levels despite HR injury. Similar results were obtained from in vivo I/R injury model. After HR injury or I/R injury the apoptosis rate of myocardial cells was highly elevated and decreased significantly only after transfection of miR-133a into cardiomyocytes. MiR-133a overexpression may inhibit I/R injury-mediated cardiomyocyte apoptosis by targeting DAPK2, leading to reduced DAPK2 protein, thus miR-133a may potentially have a high therapeutic value in I/R injury.

Characterization and Functional Analysis of Extracellular Vesicles and Muscle-Abundant miRNAs (miR-1, miR-133a, and miR-206) in C2C12 Myocytes and mdx Mice

“…Moreover, miR-133a attenuates hypoxia-induced apoptosis by suppressing caspase-8 signals via its inhibition of the TAGLN2 gene in cardiomyocytes [61]. It was recently demonstrated that miR-133a inhibits injury-induced cardiomyocyte apoptosis by targeting the DAPK2 gene [62]. In our study, caspase-3 activity was decreased by miR-133a via EVs in C 2 C 12 cells under conditions of cell stress.…”

miR-613 suppresses ischemia-reperfusion-induced cardiomyocyte apoptosis by targeting the programmed cell death 10 gene

“…Thus far, numerous miRNAs have been reported to be associated with myocardial I/R injury by regulating target genes, including miR-451, miR-133a, and Lin28a (11)(12)(13). The current study investigated the potential role of miR-613 in myocardial I/R injury and results indicated that the level of miR-613 expression decreased by 43% in H9c2 cells after H/R treatment in comparison to the level of expression in the controls.…”

Propofol protects against hepatic ischemia/reperfusion injury via miR‐133a‐5p regulating the expression of MAPK6

“…Li et al (2015) reported that miR-133a overexpression might inhibit I/R injury-mediated cardiomyocyte apoptosis by targeting death associated Figure 5 The effect of MAPK6 on the function of propofol on cell apoptosis induced by H/R. miR-133a-5p was a member of the miR-1/ miR-133 cluster of miRNAs.…”