Objective To investigate the role and mechanism of miR-138-5p in autophagy induced by manganese chloride (MnCl2) in human neuroblastoma SH-SY5Y cells.
Methods SH-SY5Y cells were treated with 0.125, 0.25, 0.5, and 1 mmol/L MnCl2, respectively. Control cells were treated with normal saline. After 6 h of the treatment, MTT test was used to detect the cell viability of SH-SY5Y cells. After 6 h of the treatment, Western blot was used to detect the expression of autophagy related proteins LC3 and Beclin1, reverse transcription PCR (RT-PCR) and western blot were used to detect the expression of miR-138-5p and the mRNA and protein expressions of histone deacetylase SIRT1. Then the cells were transfected by miRNA mimics to induce overexpressed miR-138-5p, and treated with 0.25 mmol/L MnCl2 for 6 h to detect the expressions of SIRT1 at mRNA and protein levels and the expressions of autophagy related proteins LC3 and Beclin1.
Results MnCl2 dose-dependently suppressed the viability of SH-SY5Y cells (trend χ2=12.42, P < 0.05). The LC3-Ⅱ/LC3-Ⅰ ratio and Beclin1 expression level were significantly elevated in the 0.25 and 0.5 mmol/L MnCl2-treated cells compared with the controls (P < 0.05). MnCl2 down-regulated the expression of miR-138-5p, and up-regulated the mRNA and protein expressions of SIRT1 (P < 0.05). Furthermore, the cells with overexpressed miR-138-5p showed decreased expression of SIRT1 both at mRNA and protein levels and decreased expressions of LC3-Ⅱ/LC3-Ⅰ and Beclin1 protein (P < 0.05).
Conclusion Overexpression of miR-138-5p suppresses manganese-induced autophagy by modulating the expression of SIRT1.
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