Functional characterization of Alzheimer´s disease genetic variants in microglia. Functional characterization of Alzheimer´s disease genetic variants in microglia

Alzheimer’s disease (AD) is an age-related neurodegenerative progressive disorder affecting 10% of people over 65. Less than 5% of patients have known causal genetic mutations while the exact cause of AD for the majority of patients, especially the late onset form, is unknown. Large scale epigenomic studies revealed that disease associated SNPs are highly enriched in cell-type-specific cis-regulatory elements. In AD, SNPs are more significantly enriched in the regulatory regions of myeloid lineages rather than the neuronal cells. However, how AD SNPs affect microglia enhancers, and more interestingly differentially affect state-specific enhancers such as activated upon stimulation, e.g. viral infection, remain largely unexplored. In this study we identified cis-regulatory elements in both resting and IFN-beta stimulated microglia and further functionally characterized how regulatory SNPs lead to immune response dysregulation in the pathogenesis of AD. Overall design: Examination of gene expression with RNA-seq in both resting and IFN-beta stimulated human iPSC and ESC-derived microglia.

阿尔茨海默病（Alzheimer’s disease, AD）是一种与年龄相关的神经退行性进行性疾病，影响10%的65岁以上人群。仅不到5%的患者存在明确的致病性遗传突变，而绝大多数患者（尤其是晚发型患者）的AD确切病因仍未明确。大规模表观基因组学研究显示，疾病相关单核苷酸多态性（single nucleotide polymorphism, SNP）在细胞类型特异性顺式调控元件中高度富集。在阿尔茨海默病中，SNPs在髓系细胞谱系的调控区域的富集程度显著高于神经元细胞。然而，AD相关SNPs如何影响小胶质细胞增强子，更有趣的是其如何差异调控状态特异性增强子（如经病毒感染等刺激后激活的增强子），目前仍尚未得到充分探索。本研究中，我们鉴定了静息状态与干扰素-β（interferon-beta, IFN-β）刺激后的小胶质细胞中的顺式调控元件，并进一步从功能层面解析了调控性SNPs如何导致阿尔茨海默病发病过程中的免疫应答失调。整体实验设计：采用RNA测序（RNA-seq）技术，检测静息状态及干扰素-β刺激后人诱导多能干细胞（induced pluripotent stem cell, iPSC）与胚胎干细胞（embryonic stem cell, ESC）分化得到的小胶质细胞的基因表达情况。