摘 要: 探讨α-突触核蛋白(α-Syn)在锰诱导神经细胞内质网应激中的作用。方法 将野生型和α-Syn基因敲除(α-Syn -/-)型C57小鼠各24只,均随机分成4组(每组6只),即对照组(腹腔注射0.9%氯化钠)和低、中、高剂量染锰组(分别腹腔注射50、100和200 μmol/kg氯化锰),注射容量为5 ml/kg,每周5次,共4周。而后处死小鼠,切取脑纹状体组织,检测锰含量、细胞凋亡率以及内质网应激和细胞凋亡相关信号分子表达情况。结果 随着锰暴露剂量的增加,野生型和α-Syn-/-型小鼠纹状体锰含量及细胞凋亡率均不断升高; 高剂量染锰组α-Syn-/-型小鼠细胞凋亡率明显高于野生型小鼠;与对照组比较,中、高剂量染锰组野生型小鼠PERK和eIF2α的磷酸化水平均明显升高,ATF4基因和蛋白表达均明显升高,IRE1磷酸化水平明显升高;中、高剂量染锰组,α-Syn-/-型小鼠PERK和eIF2α蛋白表达升高,而磷酸化水平相对下降,IRE1磷酸化水平明显升高;高剂量组的总XBP-1及割裂的XBP-1基因表达升高,ATF6蛋白表达升高,野生型和α-Syn-/-型小鼠CHOP和割裂的 Caspase12蛋白表达均明显高于对照组,细胞凋亡率,IRE1磷酸化水平,CHOP和割裂的Caspase12蛋白表达则均明显高于野生型。结论 α-Syn与锰诱导内质网应激PERK-eIF2α信号通路的活化有关,而且α-Syn对锰诱导的细胞凋亡在一定程度上有保护作用。 |
关键词: 锰 α-突触核蛋白 内质网应激 神经毒性 |
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基金项目: 国家自然科学基金资助(编号:81773377) |
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Effect of alpha-synuclein on manganese-induced ER stress in neurocyte of mice |
TAN Xuan,XU Bin,WANG Can,YAN Dong-ying,LIU Chang,MA Zhuo,LIU Wei,DENG Yu, XU Zhao-fa
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School of Public Health,China Medical University,Shenyang, 110122,China
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Abstract: To explore the effect of α-Synuclein (α-Syn) on manganese-induced ER stress in neurocytes. Methods 24 wile-type C57 mice (α-Syn+/+) and 24 α-Syn gene knockout mice (α-Syn-/-) were all randomly divided into four groups respectively:first group was control group, the mice were given 0.9%NaCl solution intraperitoneally (i.p.);the mice in second, third and fourth group were given 50,100 and 200 μmol/kg MnCl2 i.p,respectively, all the injection volumes were 5 ml/kg,five times a week, for 4 weeks. After last injection, mice were killed,The striatum were isolated for detecting the Mn level, the neuronal apoptosis rate,and the expressions of molecules related to the signaling pathways of endoplasmic reticulum stress and apoptosis. Results The results showed that with the increase of Mn exposure level,the Mn level and apoptosis rate in striatum were all constantly increasing both in the α-Syn+/+ and α-Syn-/- mice, the apoptosis rate of α-Syn-/- mice was markedly higher than that of α-Syn+/+mice at high level exposure of Mn; compared with control group, the expressions of phospho-PERK and phospho-eIF2α proteins, the expression of phospho-IRE1 protein,and expression of ATF4 mRNA and protein as well in α-Syn+/+ mice of medial- and high-dose Mn-treated group, were all significantly increased. Meanwhile in α-Syn-/-mice of high-dose Mn-treated group,there was some decrease in phosphorylation level, but the protein expression of PERK and eIF2α, expressions of XBP-1 mRNA, as well as the expression of ATF6 protein were significantly increased and the apoptosis rate, the phosphorylation level of IREI and the protein expression of CHOP and spliced-Caspase12 were all increased compared with wild mice. Conclusion The results suggested that α-Syn may be associated with activation of PERK-eIF2α signaling pathway in ER stress induced by Mn exposure, and α-Syn may have a protective effect on Mn-induced apoptosis. |
Keywords: Manganese alpha-synuclein endoplasmic reticulum stress neurotoxicity |