Aβ1-42寡聚体在非Caspase依赖性细胞凋亡通路中的作用机制

摘要

目的:观察Aβ1-42寡聚体对凋亡诱导因子(AIF)在神经细胞线粒体或细胞核中表达的影响.方法:将体外培养原代神经细胞分为对照组和Aβ1-42寡聚体处理组,(分别用0.1、0.2、0.5及1μmol/L的Aβ1-42寡聚体处理24h),采用MTT法测定神经细胞的相对生存率,Western blotting检测凋亡诱导因子(AIF)在神经细胞的线粒体和细胞核中的表达.结果:MTT结果显示,与对照组比较,Aβ1-42寡聚体处理组的OD值均有不同程度的下降,Aβ1-42寡聚体为0.1、0.2及0.5 μmol/L时的细胞相对生存率明显降低(P＜0.05),1μmol/L时降低最明显(P＜0.01);与对照组比较,Aβ1-42寡聚体处理组神经细胞线粒体中AIF蛋白表达减少(P＜0.05或P＜0.01),而细胞核中AIF蛋白表达升高(P＜0.05或P＜0.01).结论:Aβ1-42寡聚体可能通过AIF介导的非Caspase依赖性细胞凋亡通路导致大鼠神经细胞的凋亡,其机制可能与Aβ1-42寡聚体促进AIF从线粒体向细胞核转移有关.%Objective:To investigate the mechanism of expression of Aβ1-42 oligomers on AIF in mitochondrion or nucleus.Methods:Cortical neuronal cultures were divided into control and Aβ1-42oligomers group.Aβ1-42 oligomers were prepared using chemically synthetic Aβ1-42 in vitro (treated by0.1,0.2,0.5,1.0μmol/L Aβ1-42oligomers for 24h),and detected relative survival rate of neuronal cells by MTT.Western blotting was used to detect the expression of AIF in neuronal mitochondria and nucleus.Results:MTT indicated that OD value of Aβ1-42oligomers treated group showed decrease in various degree comparing with control group;with the Aβ1-42oligomers as 0.1,0.2 and 0.5 μmol/L,relative survival rate of cells were obviously lowered(P ＜0.05),while at 1 μmol/L reached the most obvious decrease(P ＜ 0.01);the protein level of AIF in the mitochondria of Aβ1-42oligomers group was significantly lower compared to control group (P ＜0.05 or P ＜0.01),while the protein level of AIF in the nucleus was significantly increased (P ＜ 0.05 or P ＜ 0.01).Conclusion:It is possible that Aβ1-42oligomers caused apoptosis of rats neuronal cell via AIF induced Caspase independent cell apoptosis pathway.The mechanism is possible to be relevant with Aβ1-42 oligomers enhancing AIF translocation from mitochondrial to nuclear.