Uemura Kengo, Kitagawa Naoyuki, Kohno Ryuichi, Kuzuya Akira, Kageyama Takashi, Shibasaki Hiroshi, Shimohama Shun
Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
J Neurosci Res. 2003 Jul 15;73(2):166-75. doi: 10.1002/jnr.10641.
Presenilin 1 interacts with beta-catenin, an essential component of the Wnt signaling pathway. To elucidate the role of presenilin 1-beta-catenin interaction in neuronal differentiation, we established SH-SY5Y cells stably expressing wild-type presenilin 1, P117L mutant presenilin 1, which is linked to the early-onset familial form of Alzheimer's disease, and D385A mutant presenilin 1, which has no aspartyl proteinase activity. We demonstrate that SH-SY5Y cells stably expressing D385A mutant presenilin 1 failed to differentiate in response to retinoic acid treatment. Retinoic acid caused an increase in nuclear beta-catenin levels in SH-SY5Y cells, which was followed by an increase in cyclin D1 protein levels. Abnormal cellular accumulation of beta-catenin was observed in D385A mutant transfected cells, whereas nuclear beta-catenin and cellular cyclin D1 levels failed to increase. Conversely, SH-SY5Y cells expressing the P117L mutant differentiated normally and showed increased nuclear beta-catenin and cellular cyclin D1 levels. These findings suggest that neuronal differentiation of SH-SY5Y cells involves the Wnt signaling pathway and that presenilin 1 plays a crucial role in Wnt signal transduction by regulating the nuclear translocation of beta-catenin.
早老素1与β-连环蛋白相互作用，β-连环蛋白是Wnt信号通路的重要组成部分。为了阐明早老素1与β-连环蛋白相互作用在神经元分化中的作用，我们建立了稳定表达野生型早老素1、与早发型家族性阿尔茨海默病相关的P117L突变型早老素1以及无天冬氨酸蛋白酶活性的D385A突变型早老素1的SH-SY5Y细胞系。我们发现，稳定表达D385A突变型早老素1的SH-SY5Y细胞在视黄酸处理后无法分化。视黄酸使SH-SY5Y细胞中核β-连环蛋白水平升高，随后细胞周期蛋白D1蛋白水平升高。在转染D385A突变体的细胞中观察到β-连环蛋白在细胞内异常积累，而核β-连环蛋白和细胞周期蛋白D1水平未能升高。相反，表达P117L突变体的SH-SY5Y细胞正常分化，核β-连环蛋白和细胞周期蛋白D1水平升高。这些发现表明，SH-SY5Y细胞的神经元分化涉及Wnt信号通路，并且早老素1通过调节β-连环蛋白的核转位在Wnt信号转导中起关键作用。
