Down-regulation of microRNA-181 b has protective effect on cerebral is-chemic injury of mice / 中国病理生理杂志

ABSTRACT

AIM:To explore the role of microRNA-181b (miR-181b) in ischemic injury and autophagy pro-tein 5 (Atg5) levels of mice .METHODS:Oxygen-glucose depletion (OGD) model in N2A cells to mimic ischemic in-jury in vitro was established .A middle cerebral artery occlusion ( MCAO) model to mimic ischemic injury in vivo was also induced in mice.The N2A cell apoptosis after OGD was assessed by in situ cell death detection kit.The Atg5 and caspase-9 expressions were determined by Western blotting .Luciferase reporter assay was performed to identify the direct binding of miR-181b with 3’-UTR of Atg5 mRNA.RESULTS:The alteration of miR-181b expression level by transfection with pre-miR-181b or anti-miR-181b significantly affected N2A cell apoptosis (P<0.05).Accordingly, the changes of miR-181b levels significantly altered the protein level of Atg 5 ( P<0.05 ) .Co-transfection of the luciferase reporters with pre-miR-181b or anti-miR-181b resulted in the inhibition or enhancement of the luciferase activities of luciferase expressing plasmid containing 3’-UTR of Atg5 mRNA (P<0.05).In addition, the miR-181b antagonist significantly reduced the cleaved caspase-9 levels in cerebral ischemic cortex of the mice after MCAO ( P<0.05 ) .CONCLUSION: Down-regulation of miR-181b plays an important role in ischemic injury of mice through regulating Atg 5 protein level.