The impact of Alzheimer's disease susceptibility alleles on microglia transcriptome

项目概要 阿尔茨海默病（AD）是一种与年龄相关的神经退行性疾病，其特征是进行性认知障碍 衰退和痴呆。尽管AD的潜在机制仍然很大程度上未知，但很明显，衰老与 大脑的损伤是这种疾病的一个关键危险因素。多项证据表明，小胶质细胞（骨髓细胞） 大脑的免疫细胞在中枢神经正常衰老的过程中发挥着至关重要的作用 AD 系统及发展.最近的遗传学研究已经确定了二十多个新的 AD 风险位点，并且 网络分析表明，这些基因座的主要部分在骨髓免疫系统中发挥作用。在 此外，在老年人、AD 受试者和 AD 小鼠模型中的小胶质细胞。这些小胶质细胞的变化如何导致 AD 尚不清楚。回答这个 这个问题是理解 AD 相关机制的重要一步。此外，这还可以 导致揭示治疗 AD 和相关神经退行性疾病的新靶标。长期来看 该项目的目标是加深我们对小胶质细胞在 AD 中的作用的了解，并识别与小胶质细胞相关的 治疗与年龄相关的中枢神经系统疾病的目标。迈出了重要的第一步 实现这一目标的关键在于了解 AD 中小胶质细胞的变化告诉我们什么： 基因和蛋白质表达和功能的变化。因此，本研究的总体目标是 识别 AD 相关的常见遗传变异，这些变异会改变基线和实验中小胶质细胞基因的表达 对炎症刺激的反应。通过结合两位 PI 在隔离和培养方面的独特专业知识 人类小胶质细胞的研究，以及人类骨髓免疫细胞的先进计算基因组学分析。在 目标 1，我们将使用 264 个现有的小胶质细胞样本，这些样本是我们之前从 103 个不同区域分离出来的 大脑捐赠者生成基因型和转录组图谱。通过将这些数据与现有的小胶质细胞相结合 转录组数据集，我们将能够生成 AD 相关基因座如何影响基因的图谱 表达（或表达数量性状位点，eQTL）和剪接（sQTL）。在目标2中，我们将使用干扰素 我们之前收集的 (IFN) 刺激的小胶质细胞样本用于描述 AD 相关风险如何 变异体改变干扰素刺激的转录组变化。这些特征将在新的小胶质细胞中得到验证 来自 15 名捐赠者的独立队列的转录组，以确定这些样本对 干扰素和Aβ并对具有不同吞噬能力的子集进行排序。转录组概况和 这两个目标将产生的表达和剪接QTL将被公开，我们 将把这些图谱应用到有关老年和 AD 脑组织和外周组织的大量可用基因数据集 单核细胞研究基因表达变化如何与小胶质细胞功能变化相关。我们一起 期望这项研究能够提供将 AD 遗传学与小胶质细胞分子机制联系起来的关键信息， 为未来模型系统的机理研究奠定基础。

PROJECT SUMMARY Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by progressive cognitive decline and dementia. Although the mechanisms underlying AD are still largely unknown, it is clear that aging of the brain is a key risk factor for this disease. Several lines of evidence indicate that microglia, the myeloid immune cells of the brain, play a crucial role in the processes involved in normal aging of the central nervous system and development of AD. Recent genetic studies have identified over twenty novel AD risk loci, and network analysis have shown that a major part of these loci play a role in the myeloid immune system. In addition, gene expression changes have been found in microglia of aged individuals, subjects with AD and in microglia in mice models for AD. How these microglia changes contribute to AD is not yet clear. Answering this question is an important step towards understanding the mechanisms involved in AD. In addition, this could lead to unravelling novel targets for treatment of AD and related neurodegenerative disorders. The long-term goal of this project is to deepen our insight into the role of microglia cells in AD and to identify microglia-related targets for treatment of age-related disorders of the central nervous system. An important first step towards reaching this goal is to understand what the changes that have been found microglia in AD tell us in terms of changes in gene and protein expression and functions. The overall objective of this study is therefore to identify the AD-associated common genetic variants that alters microglia gene expression at baseline and in response to inflammatory stimuli. By combining the unique expertise of the two PIs in the isolation and culture of human microglia, as well as advanced computational genomics analysis of human myeloid immune cells. In Aim 1, we will use 264 existing microglia samples that we have previously isolated of different regions of 103 brain donors to generate genotype and transcriptome profiles. By combining these data with existing microglia transcriptomic datasets, we will be able to generate a map of how AD-associated genetic loci influence gene expression (or expression quantitative trait loci, eQTL) and splicing (sQTL). In aim 2, we will use interferon (IFN) stimulated microglial samples that we have previously collected to characterize how AD-associated risk variants alter IFN-stimulated transcriptome changes. These profiles will be validated in new microglia transcriptomes from an independent cohort of 15 donors to determine the response of these samples to interferon and Aβ and sort subsets with different phagocytic capacity. The transcriptome profiles and expression and splicing QTL that will be generated in these two aims will be made publically available and we will apply these profiles to very large available gene datasets on aged and AD brain tissue and peripheral monocytes to investigate how gene expression changes relate to changes in microglia function. Together, we expect that this study will provide key information bridging AD genetics to molecular mechanisms in microglia, setting the stage for future mechanistic studies in model systems.