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.

项目概要全基因组关联研究已经确定了许多与免疫相关的阿尔茨海默病 (AD) 风险基因其中包括小胶质细胞受体 CD33 和 TREM2。 CD33 减弱了 5XFAD 小鼠的淀粉样蛋白 β (Aβ) 病理学并改善了认知能力，这两者均通过额外的 Trem2 敲除消除在 5XFAD 小鼠中敲除 Trem2 会加剧 Aβ 病理学，并且小胶质细胞的 RNA-seq 分析显示，神经退行性变但小胶质细胞数量减少。在 5XFAD;Trem2-/- 小鼠中，吞噬作用和信号传导（IL-6、IL-8、急性期反应）下调。 5XFAD;CD33-/-小胶质细胞中的差异基因表达依赖于 Trem2 的存在，表明 TREM2 作用于 CD33 下游，我们报道了 TREM2 的 D87N 和 T96K 变体。基于 NIMH 家族的遗传数据和 ADSP 病例对照样本中的 AD 风险增加，并表明在我们的初步研究中，我们发现这些增加的变体与 TREM2 配体的结合。 Trem2T96K 变异增加了不溶性 Aβ42 的水平，但减少了小胶质细胞的数量和聚集 5XFAD 小鼠 Aβ 斑块周围的小胶质细胞此外，Trem2T96K 变体减少了 sTrem2 的分泌。最后，在 5XFAD 小鼠中，T96K 变异导致 TREM2 的细胞表面表达和分泌减少。在这里，我们建议 1) 评估 TREM2 功能获得突变对人小胶质细胞系的影响。 AD 发病机制，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 TREM2 功能获得突变以及靶点 TREM2 用于治疗目的在目标 1 中，我们将检查功能获得性 Trem2T96K 的效果。 5XFAD 小鼠中 Aβ 病理学、神经变性和斑块相关神经炎性营养不良的突变。还将确定 Trem2T96K 是否影响 5XFAD 小鼠的认知功能。在目标 2 中，我们将进行研究。功能获得性 Trem2T96K 突变对小胶质细胞激活和招募 Aβ 的影响 5XFAD 小鼠的斑块以及对脂多糖刺激的免疫反应。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与在目标 3 中，我们将分析来自 NIMH 家族的全基因组测序数据。样本和 NIA ADSP 来识别新的 AD 相关 TREM2 突变，这些突变将以其特征为特征然后我们将介绍新的 TREM2 功能获得性作用。使用 CRISPR/Cas9 系统对 iPSC 衍生的人类小胶质细胞样细胞进行突变并研究潜在的突变最后，我们将预测并验证模拟 TREM2 激活的新型靶向药物。和/或使用计算方法反对 TREM2 功能丧失该提案的主要目标是。全面评估TREM2功能获得性突变对AD发病机制的影响并探讨潜在的分子网络，这将促进针对 TREM2 的 AD 治疗。