The Effect Of MicroRNA-30a On Hypoxia/Reoxygenate-induced Autophagy In Neonatal Rat Cardiomyocytes By Regulating Beclin-1

ObjectiveTo observe the expression changes of microRNA-30a (miR-30a) in neonatal ratcardiomyocytes after hypoxia/reoxygenation (H/R), to explore the potential molecularmechanism of miR-30a in regulating autophagy after H/R.MethodsThe miR-30a expression levels of control group and H/R group were detected byrealtime-PCR. The miR-30a overexpression and downexpression were induced inprimary neonatal rat cardiomyocytes by Adenovirus infection. The cardiomyocyteswere divided into5groups: control group, H/R group, AD-rno-miR-NC+H/R group,AD-rno-miR-30a+H/R group and AD-rno-miR-30a-inhibition+H/R group. Theexpression level of miR-30a after infection was determined by realtime-PCR. Theprotein levels of Beclin-1and LC3B after infection and H/R were detected by westernblotting and flow cytometry analysis, the apoptosis level were analyzed by flowcytometry.ResultsThe miR-30a level was significantly decreased after H/R (P<0.01). Theadenoviral vectors expressing the mature miRNAs were successfully constructed.The expression level of miR-30a after infected with AD-rno-miR-30a wassignificantly increased (P<0.01). Compared with AD-rno-miR-NC group, theBeclin-1and LC3B protein level was significantly down-regulated in cardiomyocyteswith miR-30a overexpression (P<0.01), the protein levels of Beclin-1and LC3B withmiR-30a downexpression were up-regulated after H/R (P<0.01), while the mRNAexpression level were not significant changed (P>0.05) in both groups. Theapoptosis of AD-rno-miR-30a+H/R group was significantly increased, while theapoptosis of AD-rno-miR-30a-inhibition+H/R group was significantly decreased.Conclusion miR-30a may be the upstream regulator of H/R-induced autophagy incardiomyoctyes by targeting Beclin-1.