Absence of miR-223-3p ameliorates hypoxia-induced injury through repressing cardiomyocyte apoptosis and oxidative stress by targeting KLF15

Abstract

Apoptosis of cardiomyocytes and oxidant stress are considered essential processes in the progression of cardiovascular diseases. A hypoxic stress which causes apoptosis of cardiomyocytes is the main problem in ischemic heart disease. The aim of the present study was to explore the functional role and potential mechanisms of miR-223-3p in hypoxia-induced cardiomyocyte apoptosis and oxidative stress. Here, we observed a increment of miR-223-3p level accompanied by the decrease of Krüppel-like zinc-finger transcription factor 15 (KLF15) expression in response to hypoxia. Additionally, absence of miR-223-3p manifestly dampened hypoxia-induced cardiomyocyte injury in H9c2 cells, including improving cell viability, attenuating the LDH leakage and preventing cardiomyocyte apoptosis accompanied by an increase in the expression of Bcl-2 and a decrease in the expression of Bax and C-caspase 3 in the setting of hypoxia. Moreover, depletion of miR-223-3p evidently retarded oxidant stress by inhibiting reactive oxygen species generation and lipid peroxidation, as well as enhancing antioxidant enzyme activity in H9c2 cells following exposure to hypoxia. More importantly, KLF15 was a direct and functional target of miR-223-3p. Further data validated that miR-223-3p negatively regulated the expression of KLF15. Mechanistically, deletion of KLF15 partly abrogated the suppressive effects of miR-223-3p deletion on hypoxia-induced cardiomyocyte apoptosis and oxidative stress. Taken all data together, our findings established that our study defines a novel mechanism by which miR-223-3p protects against cardiomyocyte apoptosis and oxidative stress by targeting KLF15, suggesting that the miR-223-3p/KLF15 may be a potential therapeutic target for ischemic heart conditions.

Keywords: Cardiomyocyte apoptosis; Myocardial infarction; Oxidative stress; miR-223-3p.