Knockdown of miR-384-3p Protects Against Myocardial Ischemia-Reperfusion Injury in Rats Through Targeting HSP70

Background: Myocardial infarction (MI) and heart failure remain critical states of heart disease with high mortality. Previous studies have indicated that miRNA has cardioprotective effects and can resist myocardial ischemia-reperfusion (I/R) injury. However, the role of mir-384-3p in MI has not been reported, and whether this miRNA can regulate the apoptosis of cardiomyocytes needs to be verified. Methods: The effect of hypoxia-reperfusion (H/R) on cardiomyocyte activity was detected using MTT assay. MiR-384-3p was knocked down or overexpressed in cardiomyocytes H/R models by pretreatment with miR-384-3p mimic or inhibitor to verify the function of miR-384-3p in H/R. Circulating levels of miR-384-3p was detected by quantitative realtime PCR, and protein expression was detected by western blotting. TUNEL staining and flow cytometry demonstrated a high degree of myocardium apoptosis after H/R induction. Dual-Luciferase Reporter Assay detected dynamic expression of miR-384-3p and HSP70. The infarction size of I/R rats was detected by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Results: MiR-384-3p was closely related to cardiomyocyte activity in H/R progression. Increased expression of mir-384-3p can promote the production of cleaved caspase-3 and cleaved PARP, thereby regulating cardiomyocyte apoptosis. HSP70 was a target of miR-384-3p and HSP70 silencing aggravated H/R-induced cardiomyocyte dysfunction. In an animal model, the expression level of HSP70 is regulated by miR-384-3p, and miR-384-3p inhibition remarkably reduced I/R-induced MI in rats. Conclusion: In conclusion, the present report identified that HSP70 was a potential target of miR-384-3p, and miR-384-3p inhibition remarkably reduced I/R-induced MI in rats. Therefore, this study provides a novel therapeutic approach for the treatment of MI from bench to clinic.