Objective To study the effect of l-melhyl-4-phenyl pyridinium (MPP+ ) on mammalian target of rapamycin (mTOR) signaling pathway in human neuroblastoma cell line SH-SY5Y. Methods The vitro cultured SH-SY5Y cells were divided into normal control group, MPP+ 0. 25 mmol/L group, 0. 5 mmol/L group and 1 mmol/L group. The-cells in MPP+ groups were cultured with corresponding MPP+ concentration tor 24 h. The cell relative survival rate of each group was detected by methyl thiazolyl tetrazolium(MTT) method. Western blot analysis was used to detected the expression of mTOR, ribosomal protein S6 kinase ( p70S6K) , rapamycin-insensitive companion of mTOR (Raptor) , rapamycin-insensitive companion of mTOR (Rictor) , and microtubule associated protein light ehain 3 ( LC3 II ) and Beclinl which related to autophagy. Results Compared with normal control group, the cell relative survival rate in each MPP+ exposure group was significantly decreased (P <0. 05 -0. 001) ; the expression of mTOR, p7OS6K, Raptor and Rictor were significantly decreased (P<0. 05 -0.001). However, the expression of LG3 II and Beclinl were significantly increased ( P < 0. 05 -0. 001 ). All effects of MPP+ had shown a dose-dependent manner. Conclusions MPP+ can induce autophagic cell death via inhibition of mTOR signaling pathway in SH-SY5Y cells in a dose-dependent manner. This may be the pathogenesis of MPP+ induced Parkinson's disease animal model.%目的 研究1-甲基-4-苯基吡啶离子(MPP+)对人骨髓神经母细胞瘤细胞株SH-SY5Y细胞哺乳动物雷帕霉素靶位(mTOR)信号通路相关蛋白表达的影响.方法 体外培养的SH-SY5Y细胞分为正常对照组、MPP+ 0.25 mmol/L组、0.5 mmol/L组及1 mmol/L组,各MPP+组细胞与含相应浓度的MPP-培养24 h.采用四甲基偶氮唑盐(MTT)法检测各组细胞相对存活率；应用免疫印迹法检测各组细胞中mTOR蛋白、核糖体蛋白S6激酶(p70S6K)、mTOR调控相关蛋白(Raptor)、雷帕霉素不敏感的mTOR伴侣蛋白(Rictor)以及与自噬相关的微管相关蛋白1轻链3(LC3Ⅱ)、Beclinl蛋白表达水平.结果 与正常对照组比较,各MPP+组细胞相对存活率显著降低(P＜0.05～0.001)；mTOR、p70S6K、Raptor、Rictor表达明显降低(P ＜0.05～0.001);LC3Ⅱ和Beclin1表达显著升高(P ＜0.05～0.001),均呈现出明显的量效关系.结论 MPP+通过抑制细胞中mTOR信号通路,诱导SH-SY5Y细胞自噬性死亡,并且与MPP+的浓度相关；这可能是MPP+导致PD动物模型发病的机制.
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