APP/PS1转基因AD模型小鼠海马自噬及相关信号通路研究

Hippocampal autophagy and related signaling pathways in APP/PS1 transgenic Alzheimer's disease model mice

目的研究β-淀粉样前体蛋白/早老素1(amyloid precursor protein/presenilin 1,APP/PS1)双转基因阿尔茨海默病(Alzheimer disease,AD)模型小鼠不同年龄阶段自噬水平变化,及蛋白激酶B(protein kinase B,Akt)/哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)传统自噬信号通路的变化。方法选取4月龄、8月龄、12月龄APP/PS1转基因AD小鼠各4只,另选择同窝4月龄、8月龄、12月龄C57BL/6小鼠各4只为对照组。采用蛋白免疫印迹法检测各组小鼠海马自噬相关蛋白Akt、p-Akt、mTOR、p-mTOR、微管相关蛋白1轻链3(microtubule-associated protein 1 light chain 3,LC3)、选择性自噬接头蛋白(sequestosome-1,p62)的表达水平。结果与对照组比较,4月龄、8月龄APP/PS1转基因AD小鼠Akt、p-Akt、mTOR、p-mTOR、LC3、p62表达量均无统计学变化(均P>0.05),12月龄APP/PS1转基因AD小鼠p-Akt/Akt、p-Akt、LC3Ⅱ、LC3Ⅱ/LC3Ⅰ升高(P<0.05)。不同月龄APP/PS1小鼠海马LC3Ⅱ蛋白表达水平及LC3Ⅱ/LC3Ⅰ比较有统计学差异(P<0.05)。结论APP/PS1转基因AD小鼠海马自噬与小鼠月龄有关。AD小鼠从12月龄开始出现自噬异常,Akt/mTOR信号通路异常激活。

Objective To investigate the changes of autophagy level and Akt/mTOR signaling pathway in APP/PS1 dual-transgenic Alzheimer's disease(AD)mice at different age stages.Methods 4 APP/PS1 transgenic AD mice aged 4 months,8 months and 12 months were selected,and 4 C57BL/6 mice aged 4 months,8 months and 12 months were selected as control groups.The expression levels of autophagy associated proteins Akt,p-Akt,mTOR,p-MTOR,microtubule associated protein 1 light chain 3(LC3)and selective autophagy adaptor protein(sequestosome-1,p62)in the hippocampus of mice in each group were detected by protein western blot.Results Compared with the control groups,4 and 8 months APP/PS1 transgenic mice had no change in Akt,p-Akt,mTOR,p-mTOR,LC3,p62 expression levels(P>0.05),but twelve months APP/PS1 transgenic mice had significantly increased Akt/Akt,p-Akt,LC3Ⅱ,LC3Ⅱ/LC3Ⅰexpression levels(P<0.05).APP/PS1 mice of different months had significant differences in hippocampus LC3Ⅱprotein expression levels and LC3Ⅱ/LC3Ⅰ(P<0.05).Conclusions The hippocampal autophagy of APP/PS1 transgenic mice was related to the age of mice.AD mice showed abnormal autophagy and abnormal activation of Akt/mTOR signaling pathway at the age of 12 months.