Coptisine up-regulates miR-146a-5p expression to attenuate injury of Parkinson's disease cell models induced by 1-methyl-4-phenylpy ridinium via PI3K/AKT pathway

Objective To investigate the effect of coptisine on 1-methyl-4-phenylpy ridinium(MPP+) induced Parkinson's disease (PD) cell injury and its mechanism. Methods SK-N-SH cells were treated with 0.3 mmol/L MPP+ to induce PD cell models (MPP+ group); normal cultured cells were used as blank controls (NCs); pretreatment with coptisine at concentrations of 10, 20, and 40 μmol/L for 4 h was performed after giving 0.3 mmol/L MPP+, different concentration coptisine treatment groups were named. And miR-con and miR-146a-5p were transfected into SK-N-SH cells and treated with 0.3 mmol/L MPP+, and named MPP++miR-con group and MPP++miR-146a-5p group; anti-miR-con and anti-miR-146a-5p were transfected into SK-N-SH cells and pretreated with 20 μmol/L coptisine for 4 h, and then, treated with 0.3 mmol/L MPP+, and named MPP++Cop+anti-miR-con group and MPP++Cop+anti-miR-146a-5p group. Cell viability was determined by MTT assay; Western blotting was used to detect the protein expressions of cleaved cysteine-containing aspartate-specific proteases-3 (caspase-3), CyclinD1, phosphorylated protein kinase B (p-AKT), p-phosphoinositide 3 kinase (p-PI3K); apoptosis was detected by flow cytometry; real-time quantitative PCR (RT-qPCR) was used to detect the miR-146a-5p expression. Results As compared with the NCs, the MPP+ induced SK-N-SH cells had significantly decreased viability and CyclinD1 and miR-146a-5p expressions, and significantly increased cleaved caspase-3 expression and apoptosis rate (P<0.05). After coptisine treatment and miR-146a-5p overexpression, MPP+ induced SK-N-SH cells had significantly increased viability and expressions of CyclinD1 and miR-146a-5p, and significantly decreased cleaved-caspase-3 expression and apoptosis rate (P<0.05). Low expression of miR-146a-5p reversed the effect of coptisine on proliferation promotion and apoptosis inhibition of SK-N-SH cells. The expression levels of p-AKT and p-PI3K in MPP+-induced SK-N-SH cells were significantly increased after coptisine treatment. Low expression of miR-146a-5p reversed the effect of coptisine on expressions of p-AKT and p-PI3K. Conclusion Coptisine can promote cell survival and inhibit MPP+-induced apoptosis, which may be related to miR-146a-5p and PI3K/AKT signaling pathways. Key words: Coptisine; MiR-146a-5p; PI3K/AKT signaling pathway; Parkinson's disease; Cell injury