miR‐15a regulates oxygen glucose deprivation/reperfusion (OGD/R)‐induced neuronal injury by targeting BDNF

Multiple microRNAs (miRs) have also been implicated in ischemic brain injury. This research intended to probe the regulatory function and the mechanism of miR‐15a on the ischemic brain injury induced by oxygen‐glucose deprivation/reoxygenation (OGD/R) in neurons of rats. The OGD/R model was established with the cortical neurons separated from rats. After transfection with miR‐15a mimic negative control (NC), miR‐15a mimic, miR‐15a inhibitor NC and miR‐15a inhibitor, the OGD/R‐induced apoptosis were detected. Using bioinformatic softwares including TargetScan, miRanda, and miRWalk to predict the underlying targets of miR‐15a, and the binding of miR‐15a with brain‐derived neurotrophic factor (BDNF) were validated with double‐fluorescein reporter assay system. The expression levels of BDNF mRNA and protein were detected with qRT‐PCR and western blot. The effect of miR‐15a on PI3K/AKT pathway in neurons submitted to OGD/R was also investigated. The findings showed that miR‐15a may mediate the apoptosis of neurons submitted to OGD/R, and lower expression of Bcl‐2 and higher expression of Bax and cleaved caspase‐3 were observed. BDNF was screened as the candidate target, and the direct binding of miR‐15a with 3′‐UTR of BDNF were verified. Further research showed that miR‐15a downregulated the expression of BDNF mRNA and protein, thus exerted negative regulatory effect on the OGD/R injury. PI3K/AKT pathway may be related to the regulatory effect of miR‐15a. Our findings contribute to uncovering novel pathogenesis for ischemic brain injury.