Down-Regulation of miRNA-30a Alleviates Cerebral Ischemic Injury Through Enhancing Beclin 1-Mediated Autophagy

• Published in: Neurochemical research 2014-07, Vol.39 (7), p.1279-1291
• Main Authors: Wang, Peng, Liang, Jia, Li, Yun, Li, Jiefei, Yang, Xuan, Zhang, Xinxin, Han, Song, Li, Shujuan, Li, Junfa
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis Regulatory Proteins - biosynthesis; Autophagy - physiology; Beclin-1; Biochemistry; Biomedical and Life Sciences; Biomedicine; Brain Ischemia - metabolism; Brain Ischemia - pathology; Brain Ischemia - prevention & control; Cell Biology; Cell Line, Tumor; Cells, Cultured; Down-Regulation - physiology; Male; Mice; Mice, Inbred C57BL; MicroRNAs - metabolism; Neurochemistry; Neurology; Neurosciences; Original Paper
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1007/s11064-014-1310-6

The understanding of molecular mechanism underlying ischemia/reperfusion-induced neuronal death and neurological dysfunction may provide therapeutic targets for ischemic stroke. The up-regulated miRNA-30a among our previous identified 19 MicroRNAs (miRNAs) in mouse brain after 6 h middle cerebral artery occlusion (MCAO) could negatively regulate Beclin 1 messenger RNA (mRNA) resulting in decreased autophagic activity in tumor cells and cardiomyocytes, but its role in ischemic stroke is unclear. In this study, the effects of miRNA-30a on ischemic injury in N2A cells and cultured cortical neurons after oxygen glucose deprivation (OGD), and mouse brain with MCAO-induced ischemic stroke were evaluated. The results showed that miRNA-30a expression levels were up regulated in the brain of mice after 6 h MCAO without reperfusion, but significantly down regulated in the peri-infarct region of mice with 1 h MCAO/24 h reperfusion and in N2A cells after 1 h OGD/6–48 h reoxygenation. Both the conversion ratio of microtubule-associated protein 1 light chain 3 (LC3)-II/LC3-I and Beclin 1 protein level increased in N2A cells and cultured cortical neurons following 1 h OGD/24 h reoxygenation. The down-regulated miRNA-30a could attenuate 1 h OGD/24 h reoxygenation-induced ischemic injury in N2A cells and cultured cortical neurons through enhancing Beclin 1-mediated autophagy, as miRNA-30a recognized the 3′-untranslated region of beclin 1 mRNA to negatively regulate Beclin 1-protein level via promoting beclin 1 messenger RNA (mRNA) degradation, and Beclin 1 siRNA abolished anti-miR-30a-induced neuroprotection in 1 h OGD/24 h reoxygenation treated N2A cells. In addition, anti-miR-30a attenuated the neural cell loss and improved behavioral outcome of mice with ischemic stroke. These results suggested that down-regulation of miRNA-30a alleviates ischemic injury through enhancing beclin 1-mediated autophagy, providing a potential therapeutic target for ischemic stroke.