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.