Abstract: Objective To explore the mechanism of miR-183 regulating mitochondrial autophagy in hypoxia/reoxygenated(H/R) hippocampal neurons. Methods The mouse hippocampal neuron HT-22 cells were collected and divided into control group, hypoxia/reoxygenation(H/R) model group (HR group), miR-183 over-expression group (miR-183 mimics group), and negative control group (miR-183 NC group). The anoxia and reoxygenation models were established by the method of anoxia 3 h+reoxygenation for 12 h, miR-183 mimics group and miR-183 NC group were transfected with miR-183 mimics and miR-183 NC on the basis of HR group. The survival rate of HT-22 cells was measured by MTT method, the ultra structure of mitochondria was microscopied and the levels of miR-183 and mitochondrial autophagy related genes Bnip3l mRNA were detected by RT-qPCR; Western blot was used to detect the expression of autophagy related proteins Bnip3l, beclin-1, ubiquitin and LC3 binding protein p62 (p62), microtubule related protein light chain 3 (LC3-Ⅱ)/LC3-Ⅰ. The targeting relationship between miR-183 and Bnip3l was verified by double Luciferase Report. Results Compared with control group, the autophagy of membrane structure in HT-22 cells increased in HR group and miR-183nc group, and melanin remained after autophagy, cell survival rate, miR-183 and p62 protein expression were all decreased (P＜0.05), the expression of Bnip3l mRNA and protein, beclin-1 and microtubule-associated protein 1 light chain 3-Ⅱ(LC3-Ⅱ)/LC3-Ⅰ proteins all increased(P＜0.05); In the miR-183 mimics group, except for the reduced cell survival rate, all the above indicators were opposite to the HR group with statistical significance (P＜0.05). Compared with miR-183 NC+ Bnip3l-3′UTR-WT group, the activity of luciferase in miR-183 mimics + Bnip3l-3′UTR-WT group decreased(P＜0.05). Conclusions The over-expression of miR-183 can target at inhibiting the expression of Bnip3l mRNA, the mitochondrial autophagy of HT-22 cells, and thus aggravate the damage of HT-22 cells caused by H/R.

Key words: microRNA-183, hippocampal neurons, mitochondrial autophagy