热休克蛋白70羧基末端相互作用蛋白调控TDP-43蛋白参与肌萎缩侧索硬化症发病的机制研究

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by progressive muscle weakness and muscle atrophy. Accumulation of ubiquitin-positive cytoplasmic inclusion bodies in motor neurons had been found as the pathological feature of ALS. Recently，TDP-43 protein was indentified as that main component of the ALS-related inclusions, therefore, abnormal ubiquitination, degradation and intracellular accumulation of TDP-43 protein was considered to be an important reason for ALS, but the regulatory mechanism of this process was still unknown. CHIP is a specific E3 ubiquitin ligase that integrated molecular chaperones and ubiquitin - proteasome system. Recently, we found that CHIP could interact with the TDP-43 protein, thus, we hypothesized that CHIP may be a specific E3 ligases for TDP-43 protein and plays an important role in the process of TDP-43 ubiquitination, degradation and intracellular accumulation, but there is still no evidence to support this hypothesis. Based on the previous new findings，this research is planned to use the methods such as RNA interference, Western-blot, Co-IP, in vivo and vitro ubiquitin assay and animal model to explore how the interaction between E3 ubiquitin ligase CHIP and TDP-43 involved in the pathogenesis of ALS. This study may has important scientific significance and may further provide new evidence for the etiology research and treatment strategies of ALS.

肌萎缩侧索硬化症（ALS）是一种临床表现为进行性肌肉无力和肌肉萎缩的致死性神经系统疾病，其特征性病理改变为运动神经元胞质内包涵体形成，其主要成分则是泛素化的TDP-43蛋白， 因此TDP-43蛋白的异常泛素化修饰、降解及细胞内聚集被认为是ALS的重要致病因素，但其调控机制尚不明了。热休克蛋白70羧基末端相互作用蛋白(CHIP)是一种整合分子伴侣和泛素蛋白酶体系统的特殊泛素E3连接酶，前期工作中我们发现：CHIP可以同TDP-43蛋白相互作用，我们推测： TDP-43可能是CHIP的底物蛋白，CHIP在TDP-43的泛素化修饰、降解及细胞内聚集过程中起到了重要作用，但无证据证实这一假说。本研究拟在此基础上，利用免疫荧光、RNA干扰、免疫印迹、免疫共沉淀、泛素化测定、转基因动物模型等技术，深入探讨CHIP与TDP-43相互作用参与ALS发病过程的机制，为ALS的病因研究和治疗策略提供新的依据。

肌萎缩侧索硬化症（ALS）是一种临床表现为进行性肌肉无力和肌肉萎缩的致死性神经系统疾病，其特征性病理改变为运动神经元胞质内包涵体形成，其主要成分则是泛素化的TDP-43蛋白， 因此TDP-43蛋白的异常泛素化修饰、降解及细胞内聚集被认为是ALS的重要致病因素。在本研究中我们发现：CHIP 蛋白与TDP-43 蛋白存在相互作用，TDP-43蛋白是CHIP的泛素化修饰底物，CHIP蛋白可在体外细胞模型调控TDP-43蛋白表达和细胞内聚集的过程，CHIP 与HDAC6 蛋白存在相互作用而TDP-43 蛋白则与HDAC6 蛋白没有相互作用，HDAC6 协同 CHIP 参与了调控TDP-43细胞内聚集，但对TDP-43蛋白的表达无影响。在CHIP（-/-）体内模型中未检测到TDP-43表达水平变化、泛素化水平变化及相关病理改变。本研究揭示了CHIP与TDP-43相互作用参与ALS发病过程的可能机制，为ALS的病因研究和治疗策略提供新的依据。