朊蛋白调节Aβ介导的细胞凋亡及作用机制初步探讨

Prion protein modulate Amyloid-β induced apoptosis and its potential mechanism

目的在阿尔茨海默病（Alzheimer’s disease，AD）细胞模型中验证PrPc朊蛋白（cellular prion protein，PrPc）是否影响神经细胞凋亡；在AD的细胞模型中探索PrPc是否影响β-分泌酶（β-site APP cleaving enzyme1，BACE1）及在AD发病中重要激酶-糖原合成酶激酶-3（glycogen synthase kinase 3 beta，GSK3β）。方法在稳定转染突变的淀粉样前体蛋白（amyloid precursor protein，APPswe）cDNA的小鼠脑神经瘤细胞（neuro-2a，N2a）中过表达pCDNA3．1-Prnp，通过4′，6-二脒基-2-苯基吲哚（4′，6-diamidino-2-phenylindole，DAPI）标记细胞核DNA。另一方面通过蛋白免疫印迹方法（westernblot）检测BACE1、GSK3β表达水平。结果稳定过表达APPswe组与pCDNA3．1-Prnp＋APPswe组较正常对照组凋亡细胞增加，而pCDNA3．1-Prnp＋APPswe组细胞核碎裂更明显。而三组之间BACE1的表达水平差异无统计学意义，APPswe组与pCDNA3．1-Prnp＋APPswe两组GSK3β表达量较正常组增加，差异有统计学意义，而两组之间差异无统计学意义。结论PrPc在AD发病中可能介导Aβ所致的神经细胞凋亡。

Objective To approve PrPc influenced neuronal apoptosis in APPswe over expression cells in order to investigate whether PrPc affects BACE1 and GSK3β expression. Methods Over expression of pCDNA3.1-Prnp in APPswe constantly transfected cell line （N2a）, and used DPAI to mark DNA of apoptosis cells, then used western blot to test BACE1, GSK3β expression levels. Results compared with the control, neuronal apoptosis induced by Aβ was dramatically increased in APPswe and pCDNA3.1-Prnp＋APPswe group, especially in pCDNA3.1-Pmp＋APPswe group. BACE1 expression had no difference in those three groups, while the level of GSK3β expression increased in APPswe and pCDNA3.1- Pmp＋APPswe groups as compared with the control, but there was no difference between these two groups. Conclusion PrPc modulates All induced neuronal apoptosis in AD.