APOC1,CLU,SORL1,APOE变异通过调控脂代谢和Abeta水平影响痴呆发病机理的研究

The objective of this application is to explore the effect of lipid metabolism and A beta (Aβ) level regulated by APOC1, CLU, SORL1 and APOE variances on late-onset alzheimer disease (LOAD) pathogenesis. Based on previous cross-sectional study in Guangxi, we intend to test and compare the variations of lipid metabolism related genes (APOC1,CLU,SORL1and APOE), levels of Aβ40-42, disease phenotype, such as LOAD degree, neurocognitive function, brain imaging and biological markers，as well as clinical and blood metabolic indicators between LOAD and cognitively normal elderly matched with LOAD, to access the impact of lipid metabolism related genes variations and their gene-gene interactions on the levels of Aβ40-42, as well as LOAD disease/metabolic phenotype in Guangxi. And then, we are going to focus on each subject to determine the relationship among risk genotypes, disease and metabolic phenotype though following up a Guangxi longitudinal LOAD cohort. We are also plan to establish an in vitro cell model to explore the functional mechanism of LOAD assciated gene variances on Aβ generation and lipid metabolism. Finally, we plan to find out the impact of lipid metabolism related genes variations on LOAD disease/metabolic phenotype, as well as LOAD pathogenesis through the research based on population, individual, cell and molecule.The research is expected to have potential application value in clinical diagnosis, intervention and prevention of LOAD.

本课题旨在探索脂代谢基因（APOC1,CLU,SORL1和APOE）变异通过调控脂代谢和Aβ水平, 影响晚发型Alzheimer病（LOAD）的发病机理。拟在前期人群研究基础上，检测和比较LOAD及与其匹配的认知功能正常老年人脂代谢基因变异，Aβ40-42水平,疾病表型（LOAD分级，神经认知功能，脑影像）及临床和血液代谢指标，识别广西LOAD人群脂代谢风险基因变异和基因交互作用，及其对Aβ40-42水平,LOAD疾病/代谢表型的影响。然后，着重研究人群中的每一受试个体，经纵向队列随访比较有/无风险基因型携带对LOAD疾病/代谢表型变化的影响，并利用体外细胞模型探索LOAD发病过程识别的基因突变对Aβ生成和脂代谢影响的功能机制。最后，经人群,个体,细胞和分子研究的综合分析，获得脂代谢基因变异与LOAD疾病/代谢表型关联和影响LOAD发病机理的证据，该结果在诊治和预防方面具有潜在价值。

晚发型阿尔茨海默病（late-onset Alzheimer’s disease，LOAD）是最常见痴呆类型，其病因不清。研究发现脂代谢基因APOE、APOC1、CLU、SORL1基因变异与LOAD发病相关。在广西人群中上述基因变异与LOAD疾病进展、对疾病表型及代谢表型影响及其机理研究未见报道。本课题拟在前期研究基础上，检测和比较 LOAD与正常对照组脂代谢基因变异、Aβ40-42水平、疾病表型及临床和血液代谢指标，识别广西 LOAD 人群脂代谢风险基因变异和基因交互作用，及其对LOAD 疾病/代谢表型影响。经纵向队列随访比较有/无风险基因型携带对 LOAD 疾病/代谢表型变化的影响，并利用体外细胞模型探索LOAD发病过程识别的基因突变和pathway机制研究，综合分析脂代谢基因变异与LOAD疾病/代谢表型的相互关联关系，及其对脂代谢影响的机制。最后，经人群、个体、细胞和分子研究的综合分析，获得脂代谢基因变异与 LOAD 疾病/代谢表型关联和影响 LOAD 发病机理的证据。本项目通过对300例AD患者和300例对照组进行研究，发现CLU 基因rs11136000多态性在中国南方AD 人群中是一个不依赖APOEε4 的风险因子（P<0.001）；通过对854例LOAD患者、1059例轻度认知功能障碍（mild cognitive impairment，MCI）患者和1254例对照组进一步的大规模人群研究，发现ESR1突变体与AD和MCI的患病风险相关，细胞内功能试验发现ESR1表达量下降，携带此突变位点的患者血清Aβ1-40 浓度升高(p=0.038)，血浆总胆固醇水平降低(p=0.009)；通过建立APOC1基因高表达、低表达的MRC-5、HepG2细胞稳转株，发现APOC1基因不影响细胞的寿命及脂代谢状态，但影响程序性细胞凋亡过程中的细胞色素C、含半胱氨酸的天冬氨酸蛋白水解酶(cysteinyl aspartate specific proteinase 3， Caspase 3 )和 Caspase 8的表达水平。为进一步探索AD的致病分子机制，找到可用于AD诊断的准确分类的生物标志物，应用RNA-seq技术对28例AD患者、12例MCI患者和4例认知正常对照三组共计44份样品开展了血液转录组测序发现：和正常对照相比，AD组和MCI组存在差异RNA表达谱。