Search for the proteins linked to Alzheimer's disease-specific neuronal death and application for the therapeutics.

细胞内β淀粉样蛋白（Aβ）42是阿尔茨海默病（AD）脑内老年斑的主要成分，在AD相关神经元死亡中可能比细胞外Aβ42更重要。以前，我们已经报道了细胞内Aβ42参与p53依赖性神经元死亡。为了进一步了解AD特异性神经元死亡的机制，我们正在寻找与该机制相关的新蛋白。近年来，我们建立了一个精细的细胞内蛋白质双向电泳差异显示系统。早老素（PS）1和2是早发性家族性AD的主要致病基因，PS 1/2基因突变与AD特异性神经元死亡密切相关。此外，外源性应激如氧化应激可触发AD中的神经元死亡。因此，我们比较了在正常条件或应激条件下，例如在培养基中去除血清，突变型PS1/2和野生型PS1/2转染的SH-SY 5 Y细胞中的蛋白质谱。在这种情况下，出现（增加）或消失（减少）的蛋白质点在应激突变PS1/2转染细胞可能是重要的与PS1/2突变相关的细胞死亡的过程。我们从500-2000个蛋白质点中筛选出一些候选蛋白质点，并尝试用质谱系统鉴定这些蛋白质。这些蛋白质可能与细胞周期、内质网应激、泛素-蛋白酶体、信号转导或其他未知系统相关。因此，2DE差异显示是寻找疾病相关蛋白质的独特工具，并且可能有助于开发AD相关神经退行性疾病的治疗方法。

Intracellular amyloid-β (Aβ) 42, the major constituent of the senile plaques in the Alzheimer's disease (AD) brain, may be even more important in the AD-related neuronal death than extracellular Aβ42. Previously, we have reported that intracellular Aβ42 contributes to the p53-dependent neuronal death. To further understand the mechanism of AD-specific neuronal death, we are searching for the novel proteins related to that mechanism. Recently, we have established a fine differential display system of intracellular proteins using 2-demensional electrophoresis (2DE). Presenilin (PS) 1 and 2 are the major causes of early-onset familial AD, and the mutations in PS1/2 are deeply associated with the AD-specific neuronal death. Also, extrinsic stress such as oxidative stress may trigger the neuronal death in AD. Thus, we compared the protein profiles in the mutant PS1/2- and wild-type PS1/2-transfected SH-SY5Y cells in the normal condition or stressed condition, e.g. deprivation of serum in the medium. In this case, appearing (increasing) or disappearing (decreasing) protein spots in the stressed mutant PS1/2-transfected cells may be importantly associated with the process of PS1/2 mutation-related cell death. We have selected some candidate spots out of total 500-2000 spots, and attempting to identify these proteins using mass-spectrometry system. Those proteins would be associated with cell cycle, ER stress, ubiquitin-proteasome, signal transduction, or unknown other systems. Thus, 2DE-differential display is a unique tool for searching for disease-related proteins, and may contribute to development of the cure of AD-related neurodegeneration.