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

项目摘要 阿尔茨海默病（Alzheimer's disease，AD）是一种与年龄相关的神经退行性疾病，以进行性认知功能障碍为特征 衰退和痴呆。虽然AD的潜在机制在很大程度上仍然是未知的，但很明显， 是这种疾病的一个关键风险因素。有几条证据表明，小胶质细胞， 大脑的免疫细胞，在中枢神经系统的正常衰老过程中起着至关重要的作用。 系统和AD.最近的遗传学研究已经确定了20多个新的AD风险基因座， 网络分析表明，这些基因座的主要部分在骨髓免疫系统中起作用。在 此外，在老年个体、AD受试者和阿尔茨海默病患者的小胶质细胞中发现了基因表达变化。 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 问题是理解AD机制的重要一步。此外，这可能 从而揭示了治疗AD和相关神经退行性疾病的新靶点。长期 本项目的目的是加深我们对小胶质细胞在AD中的作用的了解，并确定小胶质细胞相关的 用于治疗与年龄相关的中枢神经系统疾病的靶点。的重要的第一步 达到这一目标是了解AD中发现的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 确定AD相关的常见遗传变异，改变小胶质细胞基因表达的基线和 对炎症刺激的反应。通过结合两名PI在隔离和培养方面的独特专业知识， 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，我们以前分离的不同地区的103 脑供体来生成基因型和转录组谱。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相关遗传位点如何影响基因的图谱。 表达（或表达数量性状基因座，eQTL）和剪接（sQTL）。在目标2中，我们将使用干扰素 (IFN)我们先前收集的刺激小胶质细胞样本，以表征AD相关风险 变体改变IFN刺激的转录组变化。这些配置文件将在新的小胶质细胞中得到验证 来自15个供体的独立队列的转录组，以确定这些样品对以下的反应： 干扰素和Aβ，并对具有不同吞噬能力的子集进行排序。转录组图谱和 将在这两个目标中产生的表达和剪接QTL将是可利用的，我们 我将把这些图谱应用于老年人和AD脑组织和外周血中非常大的可用基因数据集。 单核细胞研究基因表达变化如何与小胶质细胞功能的变化相关。一起我们 期望这项研究将提供关键信息，将AD遗传学与小胶质细胞的分子机制联系起来， 为模型系统中未来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.