PARL基因突变与阿尔茨海默病遗传风险及其作用机制研究

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease leading to severe memory loss in elderly population. The presenilin associated, rhomboid-like (PARL) protein is an evolutionarily conserved protease residing in mitochondrial inner membrane. PARL interacts with the COOH-terminus of presenilin (PSEN), which is the catalytic core of γ-secretase and has been proved to be a pathogenic gene for familial AD. However, the physiological function of the interaction between PARL and PSEN is still unknown. As an inner mitochondrial membrane protease, PARL also regulates apoptosis and mitophagy through cleaving OPA1 and PINK1, respectively. It is of note that these PARL-associated pathways are all actively involved in AD pathology. However, there is still no report concerning the potential genetic association of the PARL gene with AD so far, and the role of PARL in AD needs to be characterized. In this study, we will carry out a comprehensive study to discern the potential association of PARL gene with AD and to characterize its role in AD pathogenesis. First, we will investigate the association between PARL genetic variants / mutations and AD by using the SNaPshot assay and targeting sequencing in Han Chinese patients with AD. Second, we will validate the genetic association results in Han Chinese by using the available datasets, such as IGAP and ExAc. Meanwhile, we will further identify the role of PARL in AD progression through data mining and integrating analyses of the available clinical information, genetic association data, eQTL data, PARL expression data, biomarker data and neuroimaging data. Finally, we will define the role of PARL and its mutants in AD-related pathways through knockdown and overexpressing of the PARL gene at the cellular level, as well as mutagenesis and knockout of the PARL gene in neural cells by using CRISPR/Cas9 technology. Our results will help to clarify whether PARL is an AD susceptibility gene and will elucidate its role in the complicated pathogenesis of AD. The valuable information that we obtain here can be used for clinical diagnosis and genetic counseling of AD, and for designing a potential therapeutic target of this disease.

阿尔茨海默病(AD)严重危害老年健康，受遗传因素影响，发病机理复杂。早老素结合蛋白PARL可与AD致病通路中的关键蛋白早老素相互作用，同时参与到与AD密切相关的细胞自噬、凋亡、胰岛素代谢等信号通路中。然而PARL基因突变是否影响AD遗传风险及其作用机制至今未明。本研究拟从3个方面集中探讨PARL在AD致病中的作用：1）利用中通量基因分型和靶向二代测序技术，分析该基因常见变异和稀有突变与我国汉族人群AD遗传风险的相关性；2）深入挖掘ADNI等报道的AD遗传与影像数据、转录组数据，验证汉族人群分析结果，发掘与基因表达、脑结构和AD生物学标记等改变相关的PARL遗传变异；3）利用基因过表达、RNA干扰、以及CRISPR/Cas9体系敲除和定点突变技术，研究PARL及其突变对细胞功能的影响，探索其参与AD的作用机制。研究结果有望解析PARL基因参与AD的致病机制，为遗传咨询和临床诊治提供依据。

阿尔茨海默病 (Alzheimer's disease, AD)是严重危害老年群体健康的主要疾病之一。早老素结合蛋白PARL和多条AD通路关联，但其在AD致病过程中的具体作用尚不清楚。本研究从遗传、细胞、患者和动物几个不同层面对PARL在AD致病通路中的作用开展系统研究，发现：1）AD患者前额皮层和内嗅皮层中，PARL基因表达水平显著下调；2）PARL基因中的遗传变异可以通过下调PARL的基因表达水平而与AD遗传风险相关；3）在细胞中，PARL的下调和敲除均导致线粒体-内质网相互作用增强，进而促进了AD致病分子Aβ的产生；4）大鼠脑片电生理中，PARL敲降导致神经信号传导减弱；在小鼠海马中下调PARL，导致记忆障碍。目前项目任务书内的研究工作已经全部完成，并超出任务书内容将研究拓展到了动物水平，对PARL参与AD的具体机制进行了系统解析。项目执行期内培养毕业硕士研究生1名，发表SCI论文1篇。团队成员2人入选中科院青促会，职称晋升3人。本研究从多个层面的数据系统构建出PARL基因型和疾病表型之间的关联，为AD这一复杂疾病提供了更多的临床早期诊治依据。