阿尔茨海默病中mir-34a作用机制的探讨

目的探讨mir-34a在阿尔茨海默病发病机制中的作用。方法取3月龄和6月龄APPswe/PSΔE9小鼠脑组织,进行microRNA芯片的检测;利用real-time RT-PCR对芯片结果进行验证;采用western blot的方法检测APPswe/PSΔE9小鼠和对照小鼠脑组织中bcl2蛋白的表达情况;通过构建mir-34a稳定转染细胞系和mir-34aknockdown研究mir-34a与bcl2之间的关系;通过构建bcl23’UTR-荧光素酶报告载体,验证bcl23’UTR序列中包含mir-34a的结合位点。结果mir-34a在模型小鼠中表达水平明显升高,并且其表达水平与bcl2蛋白水平呈负相关;通过体外实验,我们发现mir-34a过表达可以明显降低bcl2蛋白水平,反之,当我们抑制mir-34a的表达以后则可以增加bcl2蛋白水平;荧光素酶报告载体实验表明bcl23’UTR序列中包含mir-34a的结合位点。结论bcl2可能是mir-34a重要的功能靶点,mir-34a的过表达可能通过下调bcl2的蛋白水平,从而参与AD的发生。

The Role of mir-34a in Alzheimer s Disease

Objective To explore the role of mir-34a in Alzheimer＇s disease.Methods A microRNA array was used for the analysis of microRNA expression from brain tissue of 3-month-old and 6-month-old APPswe/PSΔE9 mice.The results of microRNA array were validated by real time PCR.The protein level of bcl2 in brain tissue from APPswe/PSΔE9 mice and control mice was detected by western blot.Through the construction of stable transfection cell line of mir-34a and mir-34a knockdown,we showed that mir-34a could regulate the expression of bcl2.Through the experiment of bcl2 3＇UTR-luciferase reporter,we showed the interaction of miR-34a with the 3＇UTR of the bcl2 mRNA.Results mir-34a is over-expressed in APPswe/PSΔE9 mice compared with age-matched controls and the expression of mir-34a is inversely correlated with the protein level of bcl2.Through the experiments in vitro,we found that mir-34a overexpression results in bcl2 down-regulation and mir-34a knockdown increased the level of bcl2 protein.Through the experiment of bcl2 3＇UTR-luciferase reporter,we proved that the 3＇UTR of bcl2 mRNA contains the binding site for mir-34a.Conclusion Our results suggested that bcl2 is an important functional target for mir-34a in AD,and the abnormal expression of mir-34a may contribute to the pathogenesis of AD,at least in part by affecting the expression of bcl2.