MicroRNA-9-5p Alleviates Oxidative Stress, Inflammation, and Apoptosis in Cerebral Ischemia-reperfusion Injury by Targeting NOX4

backgroundPrior research has displayed that the dysregulation of miR- 9-5p is related to cerebral ischemia-reperfusion (I/R) injury. However, the underlying neuroprotective mechanism of miR-9-5p in cerebral I/R injury has not been clarified. MATERIALS AND

methodsThe cerebral I/R injury was simulated by oxygen-glucose deprivation/reperfusion (OGD/R) model that was constructed in human SH-SY5Y cells. Changes in reactive oxygen species (ROS) and superoxide dismutase (SOD) levels were detected with the commercial kits. ELISA assay was applied for measuring the expressions of inflammatory cytokines. Western blot was used for testing the protein levels. Cell apoptosis was measured by TUNEL assay. RESULTS AND DISCUSSION: MiR-9-5p expression was dramatically decreased, while NADPH oxidase 4 (NOX4) expression was significantly increased in SH-SY5Y cells under OGD/R operation. MiR-9-5p over-expression dramatically inhibited OGD/Rinduced oxidative stress, inflammation, and apoptosis in SH-SY5Y cells. Mechanistically, results from luciferase reporter assay demonstrated that NOX4 was a target of miR-9-5p, and NOX4 over-expression partially reversed the effects of miR-9-5p mimic on oxidative stress, inflammation, and apoptosis in OGD/R SHSY5Y cells.

conclusionMiR-9-5p over-expression suppressed oxidative stress, inflammation, and apoptosis in cerebral I/R injury by targeting NOX4, suggesting that miR-9-5p might be a new anti-inflammatory and anti-oxidative modulator in cerebral I/R injury.