MicroRNA-486-5p down-regulation protects cardiomyocytes against hypoxia-induced cell injury by targeting IGF-1.

backgroundMicroRNA has been reported to play an important role in congenital heart disease (CHD) in children. Recently, microRNA-486-5p (miR-486-5p) has been found increased in patients with cyanotic heart disease compared with those without heart disease. The present study aimed to investigate the effect of miR-486-5p on hypoxia-induced cardiomyocyte injury to reveal the role of miR-486-5p in cyanotic congenital heart disease (CCHD).

methodsReverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine the expression of miR-486-5p in hypoxia-induced H9C2 cells. Dual luciferase reporter gene assay was used to confirm IGF-1 was a direct target of miR-486-5p. miR-486-5p inhibitor and IGF-1-siRNA were transfected into H9C2 cells. The cell viability was detected by MTT. Cell apoptosis was detected using flow cytometry. The expression of IGF-1, Bcl-2, caspase-3, caspase-9, and Bax mRNA and protein were detected by RT-qPCR and western blotting, respectively.

resultsmiR-486-5p expression gradually increased with prolonged hypoxia time in H9C2 cells. Dual luciferase reporter gene results confirmed IGF-1 was a direct target of miR-486-5p. In addition, inhibition of miR-486-5p significantly increased the hypoxia-induced decrease in cell survival and attenuated hypoxia-induced apoptosis. Furthermore, inhibition of miR-486-5p significantly attenuated the hypoxia-induced decrease in the level of IGF-1 and Bcl-2 and the increase in pro-apoptotic proteins such as caspase-3, caspase-9 and Bax. These effects could be reversed by IGF-1-siRNA.

conclusionThe data demonstrated that inhibition of miR-486-5p increased cardiomyocyte growth and reduced cell apoptosis under hypoxic conditions by targeting IGF-1, indicating that miR-486-5p may be an effective target for the treatment of CCHD.