Neuroprotective effect of microRNA-99a against focal cerebral ischemia–reperfusion injury in mice

• Published in: Journal of the neurological sciences Vol. 355; no. 1-2; pp. 113 - 119
• Main Authors: Tao, Zhen, Zhao, Haiping, Wang, Rongliang, Liu, Ping, Yan, Feng, Zhang, Chencheng, Ji, Xunming, Luo, Yumin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.08.2015
• Subjects: Animals; Brain Ischemia - complications; Brain Ischemia - drug therapy; Caspase 3 - metabolism; CDK6; Cell cycle; Cell Cycle - drug effects; Cell Line, Tumor; Cerebral ischemia; Cyclin D1; Cyclin D1 - metabolism; Cyclin-Dependent Kinase 6 - metabolism; Disease Models, Animal; Gene Expression Regulation - drug effects; Hydrogen Peroxide - pharmacology; In Situ Nick-End Labeling; L-Lactate Dehydrogenase - metabolism; Male; Mice; Mice, Inbred C57BL; MicroRNAs - agonists; MicroRNAs - antagonists & inhibitors; MicroRNAs - genetics; MicroRNAs - metabolism; MiR-99a; Neuroblastoma - pathology; Neurology; Neuroprotective Agents - therapeutic use; Oxidants - pharmacology; Oxidative stress; Reperfusion Injury - blood; Reperfusion Injury - prevention & control; Statistics, Nonparametric; Transfection; Oxidative stress; Cerebral ischemia; CDK6; Cyclin D1; Cell cycle; MiR-99a
• ISSN: 0022-510X; 1878-5883; 1878-5883
• DOI: 10.1016/j.jns.2015.05.036

MicroRNA-99a (miR-99a) has been reported to function as a tumor suppressor through regulating cell cycle and apoptosis. But its clinical significance in ischemic stroke and its function in cerebral ischemia–reperfusion (I/R) injury remained unknown. Herein transient middle cerebral artery occlusion was built on C57BL/6 mice, followed by intracerebroventricular injection of miR-99a agomir or antagomir before reperfusion for 24h. Our clinical analysis indicates that plasma miR-99a level was significantly decreased in ischemic stroke patients as compared to healthy subjects, and a significant correlation was observed between miR-99a and clinical parameters. And miR-99a overexpression mitigated I/R injury in mice, as evidenced by reduced brain infarct volume and neural apoptosis, whereas miR-99a downregulation aggravates brain injury. In vitro, miR-99a protected neuro-2a cells against hydrogen peroxide-induced oxidative stress injury, by improving cell viability, suppressing LDH release and cell apoptosis. In addition, miR-99a overexpression inhibited H2O2 induced G1/S phase transition in neuro-2a cells, accompanied by a significant decrease in cyclin D1 level and a tendency of down-regulation of CDK6. It was further proved in mice that miR-99a inhibited cyclin D1 and CDK6 expressions following cerebral I/R injury. These findings indicate that miR-99a reduces neuronal damage following cerebral I/R through regulating cell cycle progression and preventing apoptosis, suggesting that miR-99a could be used as a new therapeutic agent targeting neuronal cell cycle re-entry following stroke. •MiR-99a level in plasma of stroke patients was correlated with clinical parameters.•MiR-99a lessened focal cerebral ischemia–reperfusion injury in MCAO mice.•MiR-99a protected neuro-2a cells from oxidative stress injury induced by H2O2.•MiR-99a prevented apoptosis and blocked cell cycle progression in neuro-2a cells.