Role of TREM2 gain-of-function mutations in modulating microglial pathology in Alzheimer's disease

TREM2 功能获得性突变在调节阿尔茨海默病小胶质细胞病理学中的作用

基本信息

批准号：
10621259
负责人：
Ana Griciuc
金额：
$ 40.64万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2026-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10621259
关键词：
Acute-Phase Reaction Aging Alzheimer&apos s Disease Alzheimer&apos s disease pathology Alzheimer&apos s disease risk Alzheimer&apos s disease therapeutic Amyloid beta-42 Amyloid beta-Protein Animal Model Astrocytosis Attenuated Binding Brain CRISPR/Cas technology Cell Culture Techniques Cell Line Cell surface Cells Cognition Collection Data Data Set Disease associated microglia Drug Compounding Family Gene Expression Gene Expression Profile Genes Genetic Genetic Databases Genetic Diseases Goals Human IL8 gene Immune response Interleukin-1 beta Interleukin-6 Knock-out Late Onset Alzheimer Disease Ligands Link Lipopolysaccharides Microglia Molecular Mus Mutation National Institute of Mental Health Nerve Degeneration Pathogenesis Pathology Phagocytosis Regulation Reporter Reporting Role Sampling Senile Plaques Signal Pathway Signal Transduction System TREM2 gene Testing Therapeutic Tissue-Specific Gene Expression Variant anakinra case control cognitive function cytokine drug development gain of function gain of function mutation genetic risk factor genome sequencing genome wide association study glial activation improved induced pluripotent stem cell insight loss of function neuroinflammation new therapeutic target novel novel therapeutics programs receptor recruit response risk variant therapeutic target transcriptome sequencing uptake whole genome

项目摘要

Project Summary Genome-wide association studies have identified many Alzheimer’s disease (AD) risk genes related to immune response. Among these are the microglial receptors CD33 and TREM2. We previously showed that knock-out of CD33 attenuated amyloid beta (Aβ) pathology and improved cognition in 5XFAD mice, both of which were abrogated by additional Trem2 knock-out. Knocking out Trem2 in 5XFAD mice exacerbated Aβ pathology and neurodegeneration but reduced microglia numbers. RNA-seq profiling of microglia revealed that genes related to phagocytosis and signaling (IL-6, IL-8, acute phase response) are downregulated in 5XFAD;Trem2-/- mice. Differential gene expression in 5XFAD;CD33-/- microglia depended on the presence of Trem2, suggesting TREM2 acts downstream of CD33. Moreover, we reported that the D87N and T96K variants of TREM2 increased AD risk in the NIMH family-based genetic data and ADSP case-control samples and showed that these variants increased binding to TREM2 ligands. In our preliminary study, we found that the gain-of-function Trem2T96K variant increased levels of insoluble Aβ42 but reduced both microglia numbers and clustering of microglia around Aβ plaques in 5XFAD mice. Furthermore, the Trem2T96K variant reduced secretion of sTrem2 in 5XFAD mice. Finally, the T96K variant led to reduced cell surface expression and secretion of TREM2 in human microglial cell lines. Here, we propose to 1) assess the impact of TREM2 gain-of-function mutations on AD pathogenesis, 2) investigate the effects of these mutations on microglial activation and gene expression, and 3) identify and characterize novel AD-associated TREM2 gain-of-function mutations as well as target TREM2 for therapeutic purposes. In Aim 1, we will examine the effects of the gain-of-function Trem2T96K mutation on Aβ pathology, neurodegeneration and plaque associated-neuritic dystrophy in 5XFAD mice. We will also determine whether Trem2T96K impacts cognitive function in 5XFAD mice. In Aim 2, we will investigate the impact of the gain-of-function Trem2T96K mutation on microglial cell activation and recruitment to Aβ plaques as well as immune response to lipopolysaccharide stimulation in 5XFAD mice. RNA-seq profiling of microglia will reveal the effects of Trem2T96K on microglial gene expression signature and how they compare to disease-associated microglia. In Aim 3, we will analyze whole genome sequencing data from the NIMH family sample and NIA ADSP to identify novel AD-associated TREM2 mutations that will be characterized for their effects on ligand-dependent activation of TREM2. We will then introduce novel TREM2 gain-of-function mutations into iPSC-derived human microglia-like cells using CRISPR/Cas9 system and investigate underlying molecular mechanisms. Finally, we will predict and validate novel targeted drugs that mimic TREM2 activation and/or oppose TREM2 loss-of-function using computational approaches. The major goals of this proposal are to comprehensively assess the effects of TREM2 gain-of-function mutations on AD pathogenesis and explore underlying molecular networks, which will facilitate AD therapeutics targeting TREM2.

项目摘要全基因组关联研究已经确定了许多与免疫有关的阿尔茨海默氏病（AD）风险基因回复。其中包括小胶质接收器CD33和TREM2。我们以前证明了淘汰赛 CD33减弱淀粉样β（Aβ）病理学和5xFAD小鼠认知的改善被额外的TREM2淘汰赛废除。在5xFAD小鼠中拆除Trem2加剧了Aβ病理学和神经变性，但小胶质细胞数量减少。小胶质细胞的RNA-seq分析表明基因相关在5xFAD中下调吞噬作用和信号传导（IL-6，IL-8，急性相响应）； trem2 - / - 小鼠。 5xFAD中的差异基因表达； CD33 - / - 小胶质细胞取决于TREM2的存在，表明 TREM2作用于CD33的下游。此外，我们报道了Trem2的D87N和T96K变体在基于NIMH家庭的遗传数据和ADSP病例对照样本中增加了AD风险，并表明这一点这些变体增加了与TREM2配体的结合。在我们的初步研究中，我们发现功能奖励 TREM2T96K变体增加了不溶性Aβ42的水平，但小胶质细胞数量和聚类减少了 5xFAD小鼠中Aβ斑块周围的小胶质细胞。此外，trem2t96k变体降低了streem2的秘密在5xfad小鼠中。最后，T96K变体导致细胞表面表达和Trem2的分泌降低人类小胶质细胞系。在这里，我们建议1）评估trem2功能获得突变对 AD发病机理，2）研究这些突变对小胶质细胞激活和基因表达的影响， 3）识别和表征新型AD相关的TREM2功能获得突变以及目标 trem2用于治疗目的。在AIM 1中，我们将检查功能获得的trem2T96K的影响 5XFAD小鼠中Aβ病理学，神经退行性变化和斑块相关的神经性营养不良的突变。我们还将确定TREM2T96K是否影响5XFAD小鼠的认知功能。在AIM 2中，我们将调查功能获得的Trem2T96K突变对小胶质细胞激活和募集到Aβ的影响 5xFAD小鼠中斑块以及对脂多糖刺激的免疫反应。 RNA-seq分析小胶质细胞将揭示trem2t96k对小胶质细胞基因表达特征的影响，以及它们如何比较疾病相关的小胶质细胞。在AIM 3中，我们将分析NIMH家族的整个基因组测序数据样品和NIA ADSP识别新型AD相关的TREM2突变，这些突变将以其特征为特征对TREM2配体依赖性激活的影响。然后，我们将介绍小说TREM2功能获得使用CRISPR/CAS9系统进入IPSC衍生的人类小胶质细胞的突变并研究基础分子机制。最后，我们将预测并验证模仿Trem2激活的新型靶向药物和/或使用计算方法对抗函数丧失。该提议的主要目标是全面评估TREM2功能获得突变对AD发病机理的影响并探索基础分子网络将促进靶向TREM2的AD疗法。