IGF-1对Aβ_(1-40)诱导PC12细胞tau蛋白过度磷酸化的保护作用及其机制研究  

Study of the Protection and Mechanism of IGF-1 on Tau Protein Hyperhosphorylation in PC12 Cells Induced by Aβ_(1-40)

作　　者：王鹏军[1] 张昱[2] 宋荣蓉[1] 申东方[1] 

机构地区：[1]哈尔滨医科大学附属四院神经内科,哈尔滨150001 [2]吉林大学第一医院神经内科,长春130021

出　　处：《四川大学学报（医学版）》2010年第6期960-964,共5页Journal of Sichuan University(Medical Sciences)

基　　金：黑龙江省教育厅基金(11541205)资助

摘　　要：目的探讨胰岛素样生长因子-1(IGF-1)对β样淀粉蛋白(Aβ1-40)引起的PC12细胞tau蛋白磷酸化的保护作用及其机制。方法通过MTT法观察不同浓度的IGF-1对PC12细胞存活的影响。应用蛋白免疫印迹方法,检测Aβ1-40处理后PC12细胞tau蛋白磷酸化、总tau蛋白、糖原合成激酶3β(GSK-3β)和磷酸化GSK-3βSer9的表达情况;观察IGF-1或GSK-3β特异性抑制剂氯化锂(LiCl)对Aβ1-40诱导PC12细胞上述指标变化的影响。结果不同浓度的IGF-1均能提高PC12细胞生存率,1μg/mLIGF-1作用最明显。tau蛋白Ser396、Ser199/202位点的磷酸化水平在Aβ1-40诱导后3h开始增高,12h达到高峰;总tau蛋白的变化趋势与tau蛋白磷酸化的改变大体一致。在tau蛋白磷酸化达高峰时,GSK-3β的表达增加而磷酸化GSK-3βSer9的表达减少。用IGF-1或LiCl处理后,可减轻Aβ1-40所诱导的tau蛋白过度磷酸化,同时GSK-3β的表达下降而磷酸化GSK-3βSer9的表达增加。结论 Aβ1-40可使PC12细胞tau蛋白Ser396、Ser199/202位点的磷酸化水平增高,该作用主要通过激活GSK-3β实现。IGF-1可抑制GSK-3β的活性,最终达到减轻Aβ1-40所诱导的PC12细胞tau蛋白过度磷酸化的作用。Objective To investigate the effect and the molecular mechanism of insulin-like growth factor 1 （IGF-1） on the level of tau protein phosphorylation in PC12 cells induced by aggregated beta-amyloid protein1-40 （Aβ1-40）. Methods MTT assay was used to measure the survival rate of PC12 cells, Western blot was applied to detect tau phosphorylation level, total tau, glycogen synthase kinase-3β （GSK-3β）, and phosphorylation of GSK-3β Ser^9 for observing the effect of IGF-1 or LiCl, a specific inhibitor of GSK-3β, on AB-induced tau protein phosphorylation in PC12 cells. Results Different concentrations of IGF-1 could improve the survival rate of PC12 cells compared with that of Aβ1-40 group （P〈0.05）, and the best protective effect was observed in 1 μg/mL IGF-1 group. The levels of tau protein phosphorylation in the sites of Ser^396, Ser^199/202 and the amount of whole tau increased after 3 h exposure and reached the maximum level after 12 h exposure to Aβ1-40, meanwhile, the expressions of the amount of whole GSK-3β was also increased （P〈0. 05）, but a decreased phosphorylation of GSK-3βSer^9 was observed （P〈0. 05）. Pretreatment with several dose of IGF-1 or LiC1, markedly reduced Aβ1-40- induced tau hyperphosphorylation and the expression of GSK-3β（P〈.Z0.05）, but the expression of phosphorylation of GSK-3βSer^9 was increased（P〈0. 05）. Conclnsion The levels of tau protein phosphorylation in the sites of Ser^396 , Ser^199/202 and the amount of whole tau increased by Aβ1-40 in PC12 cells, GSK-3β activation by Aβ1-40 may lead to extensive tau phosphorylation. IGF-1 could attenuate Aβ1-40-indueed tau protein hyperphosphorylation by inhibiting the activation of GSK-3β.

关 键 词：胰岛素样生长因子-1 阿尔茨海默病 糖原合成酶激酶-3 TAU蛋白磷酸化 

分 类 号：R749.16[医药卫生—神经病学与精神病学]