血管内皮细胞来源的淀粉样前体蛋白（APP）对成体神经干细胞增殖分化以及凋亡调控的分子机制研究

项目名称： 血管内皮细胞来源的淀粉样前体蛋白（APP）对成体神经干细胞增殖分化以及凋亡调控的分子机制研究

项目编号： No.31201100

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 发育生物学与生殖生物学

项目作者： 胡晶琼

作者单位： 华中科技大学

项目金额： 26万元

中文摘要： 成体神经干细胞存在于血管内皮细胞构成的微环境中，微血管内皮细胞对成体神经干细胞特性的维持起重要作用，但具体调控机制不明。项目申请人的前期研究通过两种不同的筛查手段同时发现淀粉样前体蛋白(Amyloid Precursor Protein，APP）是微环境中可能的重要调控因子。初步的体外实验发现，过度表达APP可以诱导成体神经干细胞球凋亡，以及完全抑制原发性以及次级神经球的发生。因此APP可能是神经干细胞微环境中重要的反向调控因子。本研究拟在前期研究基础上进一步揭示APP的时空表达特点，通过体外EC-NSC共培养模型结合APP过表达以及靶向沉默技术观察APP对成体神经干细胞增殖，分化以及凋亡的影响，并创新性的运用RCAS-TVA系统以及脑内立体定向注射达到在体观察APP功能的目的。该研究将首次揭示血管内皮源性APP在神经干细胞微环境的调控作用，为老龄化以及神经退行性疾病的研究提供新的思路。

中文关键词： 脑微血管内皮细胞；神经干细胞；干细胞微环境；淀粉样前体蛋白；凋亡

英文摘要： Endothelial cells have close interactions with neural stem cells in adult neurogenic regions and have been implicated to provide niche signals for adult neurogenesis. However, the identity of endothelial derived niche factors remains elusive. We took two different approaches to address this question. First we performed cDNA microarray analysis and obtained a list of around 80 genes by comparison of the expression profile of niche and non-niche endothelial cells using adult Tie-2 GFP transgenic mice. Next we used Retroviral Mediated Signal Trap technology to identify all cDNAs encoding secreted or membrane-bound protein in endothelial cells from subventricular zone (SVZ) of Tie-2 GFP transgenic mice. A total of 220 positive clones were screened. 94 secreted or membrane-bound proteins were identified. Interestingly, the APP (Amyloid Precursor Protein) was identified as highly overrepresented in both approaches. Our preliminary ex vivo cell culture experiments showed N-APP overexpression conditioned medium completely abolished de novo neurosphere formation, inhibited secondary neurosphere formation and induced neurosphere apoptosis. Although APP is well established for its neurotoxicity in neurodegenerative diseases, its function in adult neurogenic niche is never demonstrated. Given current findings, we speculat

英文关键词： brain vascular endothelial cells；neural stem cell；microenvironment；Amyloid precursor protein；apoptosis