Cedazo-Mínguez A, Wiehager B, Winblad B, Hüttinger M, Cowburn R F
Karolinska Institutet, NEUROTEC, Section for Geriatric Medicine, NOVUM, KFC, plan 4, S-141 86 Huddinge, Sweden.
Neurochem Int. 2001 Jun;38(7):615-25. doi: 10.1016/s0197-0186(00)00128-5.
We investigated the effects of different apolipoprotein E (apoE) isoforms, Abeta (1-42), and apoE/Abeta complexes on PKC-alpha translocation and APP processing in human SH-SY5Y neuroblastoma cells and fibroblasts. Treatment of cells with either 10 nM apoE3 or apoE4, 10 microM Abeta (1-42), or apoE/Abeta complexes induced significant translocation of PKC-alpha in both cell types. Effects were seen using both human recombinant apoE and apoE loaded into beta-very low density lipoprotein (beta-VLDL) particles. Time course (5-24 h) studies of APP processing revealed that some conditions induced transient or moderate increases in the secretion of proteins detected by 22C11. In contrast, the secretion of alpha-secretase cleaved APP was either not modified or transiently decreased, as determined by immunoblotting with the antibody 6E10. These results suggest that apoE, Abeta (1-42) and apoE/Abeta complexes can modulate PKC activity but do not have major consequences for APP processing. These effects could contribute to the reported PKC alterations seen in AD. However, it is unlikely that the contribution of different apoE isoforms to AD pathology occurs via effects on APP processing.
我们研究了不同载脂蛋白E（apoE）异构体、β淀粉样蛋白（Abeta，1-42）以及apoE/Abeta复合物对人SH-SY5Y神经母细胞瘤细胞和成纤维细胞中蛋白激酶C-α（PKC-α）易位及淀粉样前体蛋白（APP）加工的影响。用10 nM的apoE3或apoE4、10 μM的Abeta（1-42）或apoE/Abeta复合物处理细胞，均可诱导这两种细胞类型中的PKC-α发生显著易位。使用重组人apoE以及装载于β极低密度脂蛋白（β-VLDL）颗粒中的apoE均观察到了这种效应。对APP加工的时间进程（5-24小时）研究表明，某些条件可诱导22C11检测到的蛋白质分泌出现短暂或适度增加。相比之下，通过抗体6E10免疫印迹测定，α分泌酶切割的APP的分泌要么未改变，要么短暂减少。这些结果表明，apoE、Abeta（1-42）和apoE/Abeta复合物可调节PKC活性，但对APP加工没有重大影响。这些效应可能导致了在阿尔茨海默病（AD）中报道的PKC改变。然而，不同apoE异构体对AD病理的影响不太可能通过对APP加工的作用来实现。
