CLU 在阿尔茨海默病中介导 Tau 蛋白在神经元间转运的作用及机制

Alzheimer's disease (AD) is the commonest neurodegenerative disease. AD patients mainly present with dementia and gradually lose their ability of life, causing great burden to the family and society. The neurofibrillary tangles caused by hyper-phosphorylated Tau play an important role in the pathogenesis of AD. Recent Genome wide association studies (GWAS) indicated that CLU gene polymorphisms affect the risk of late onset AD. Our previous studies found that CLU gene was involved in the pathogenesis of AD and many cell functions, such as endocytosis and apoptosis. In addition, CLU played crucial role in regulating the actin cytoskeleton. What is more, CLU may modulate the stability of the microtubule network by binding to the protein that maintains microtubule stability. Therefore, we speculated that CLU may lead to Tau dysfunction and subsequently causing AD. In this study, we will generate AD cell model by transfecting CLU-GFP plasmid into SH-SY5Y cell, and AD animal model with Tg4510 mice. Using small interfering RNA and MTT, we will detect the toxic effects of SH-SY5Y on the phosphorylated Tau after the up-regulation of CLU, and the expression level of phosphorylated Tau and apoptosis related protein. We will also investigate the interaction of CLU with Tau and F-actin by using co-immuno-precipitation method. The aim of this study is to explore the role and potential mechanisms of CLU mediated Tau protein transport in neurons of AD model.

阿尔茨海默病（AD）是最常见的神经变性病，患者以痴呆为主要表现，生活不能自理，给家庭和社会造成极大负担。Tau的异常磷酸化导致的神经元纤维缠结在AD发病中起重要作用。最近GWAS研究发现CLU基因多态性影响晚发型AD发病风险。我们课题组前期研究发现CLU基因参与AD的发病风险，CLU参与多种细胞功能：细胞内吞、细胞凋亡等，CLU在调节肌动蛋白细胞骨架有重要作用，CLU可能通过与维持微管稳定的蛋白结合，从而调节微管网络的稳定性。因此，推测CLU在AD发病中与Tau功能异常有关。本研究利用AD细胞模型，利用AD小鼠模型（Tg4510）小干扰RNA技术检测CLU上调后SH-SY5Y细胞对磷酸化Tau的毒性反应、磷酸化Tau蛋白以及凋亡相关蛋白表达水平变化，应用免疫共沉淀等方法研究CLU、Tau蛋白及F-actin等的相互作用关系，探讨CLU在AD中介导Tau蛋白在神经元间转运的的作用及可能机制。

简介:阿尔茨海默病(Alzheimer's disease, AD)是一种以tau蛋白异常磷酸化所致神经纤维缠结(neurofibrillary tangles, NFTs)为病理特征的神经退行性疾病。研究发现，Clusterin (CLU)基因是参与AD发病的第三大易感基因，同时研究证实细胞外的TAU蛋白可通过胞吞作用进入神经元细胞中，在病理诊断为TAU蛋白病变的AD患者海马组织出现萎缩。因此，CLU表达增高促进了AD中TAU的病理传播。方法:采用过表达或抑制CLU的SH-SY5Y细胞转染模型，通过不同构象的外源TAU蛋白与模型细胞共孵育，检测不同时间点细胞形态及相关蛋白表达随细胞外TAU内吞进入模型细胞的变化。结果:CLU表达的变化对细胞内TAU的表达有正向影响，CLU调节外源性TAU单体、TAU PFFs和TAU重组蛋白进入胞内细胞质，共孵育12h后，导致神经元内TAU聚集形成NFT。结论:CLU介导TAU蛋白进入神经元聚集形成NFTs，从而导致AD的发生。