Role of clonal somatic mutations in microglia activation and Alzheimer’s disease

克隆体细胞突变在小胶质细胞激活和阿尔茨海默病中的作用

• 批准号: 10901003
• 负责人: Yue Huang
• 金额: $ 88.32万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10901003
• 关键词: 3-Dimensional; Age; Aging; Alzheimer' s Disease; Alzheimer' s disease brain; Alzheimer' s disease patient; Alzheimer' s disease risk; Autopsy; BRAF gene; Bar Codes; Benchmarking; Bioinformatics; Brain; Brain region; Cell Cycle; Cell Fraction; Cell Proliferation; Cells; Clinic; Clonal Expansion; Code; Collection; Data; Data Analyses; Development; Gender; Genes; Genetic; Genetic Risk; Histiocytosis; Human; Human body; Immune; Innate Immune System; Link; Measures; Methods; Microglia; Mutate; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Play; Population; Process; Proliferating; Publishing; RNA; Reporting; Role; Sampling; Single Nucleotide Polymorphism; Somatic Cell; Somatic Mutation; Technology; Testing; Validation; age effect; age related; cancer risk; cell type; cohort; differential expression; human disease; insertion/deletion mutation; large datasets; mind control; mouse model; mutant; nervous system disorder; neuroinflammation; neuron loss; novel; single-cell RNA sequencing; transcriptome; transcriptome sequencing

Project Summary/Abstract Alzheimer’s disease (AD) and other neurodegenerative diseases are characterized by age-related onset and progressive neuronal loss. Neuroinflammation, the activation of the brain's innate immune system, is known to be critically involved in the initiation and development of neurodegeneration. As the primary immune cells in the brain, activated microglia have been recently reported to promote neuronal death during AD pathogenesis, yet the mechanisms by which age and genetic risk interact remain largely unknown. Somatic mutations accumulate in various cell types during the development and aging process of the human body. Clonal expansion of certain cell populations, driven by somatic mutations in genes regulating cell proliferation, has long been associated with an increased risk of cancer with age, but has only recently been linked to a growing list of non-cancer neurological diseases. Notably, somatic BRAF mutation in the microglial lineage has been implicated in histiocytosis-associated neurodegenerative conditions. Our preliminary results from two AD cohorts and with two sequencing technologies consistently show an excess of clonal somatic mutations in AD brains, particularly in proliferation-related genes of microglia. This new study aims to examine if the accumulation of somatic mutations contributes to an age-related increase of AD risk by activating clonal expansion of microglia, which subsequently induces neuroinflammation and neuronal loss in AD brains. The first Aim of the study is to identify somatic mutations by re-analysis of the existing bulk and single-cell RNA-seq datasets from large AD cohorts, and compare the transcriptome-wide burden and distribution of somatic mutation between different brain regions of AD patients and age-matched controls. In the second Aim of the study, molecule-barcoded ultra-deep panel sequencing will be applied to screen for clonal somatic mutations more sensitively among genes that regulate cell cycle and proliferation in AD and control brains, which will enable us to explore frequently mutated genes or pathways that may drive the clonal expansion of carrier cells during AD pathogenesis. The third Aim of the study will focus on the mutant fraction and functional impact of potentially pathogenic somatic mutations across different cell types in AD brains, especially for microglia, by combining single-cell RNA-seq and PRDD-seq, a method we developed for parallel analysis of somatic mutation and cell-type information from the same single-cells. The results of our study will shed new light on the contribution of somatic mutation to increased AD risk, and highlight the clonal expansion of microglia triggered by somatic mutations in proliferation-related genes as a potential mechanism of AD pathogenesis.

项目概要/摘要 阿尔茨海默病 (AD) 和其他神经退行性疾病的特点是与年龄相关 神经炎症（大脑先天免疫系统的激活）的发生和进行性损失。 已知与神经退行性变的起始和发展密切相关。 最近有报道称，激活的小胶质细胞会促进 AD 期间神经元的死亡 发病机制，但年龄和遗传风险相互作用的机制仍然很大程度上未知。 在人体的发育和衰老过程中，各种细胞类型中都会积累突变。 由调节细胞增殖的基因的体细胞突变驱动某些细胞群的克隆扩张， 长期以来，人们一直认为它与随年龄增长而增加的癌症风险有关，但直到最近才被认为与 越来越多的非癌症神经系统疾病值得注意的是，小胶质细胞谱系中的体细胞 BRAF 突变。 我们从两个 AD 中得到的初步结果与组织细胞增多症相关的神经退行性疾病有关。 队列和两种测序技术一致显示 AD 中存在过多的克隆体细胞突变 大脑，特别是小胶质细胞增殖相关基因。 这项新研究旨在检查体细胞突变的积累是否会导致与年龄相关的疾病 通过激活小胶质细胞的克隆扩张增加 AD 风险，随后诱导神经炎症 该研究的第一个目的是通过重新分析来识别体细胞突变。 来自大型 AD 队列的现有批量和单细胞 RNA-seq 数据集，并比较全转录组 AD患者和年龄匹配的不同脑区体细胞突变的负担和分布 在该研究的第二个目标中，分子条形码超深面板测序将应用于 在调节细胞周期和增殖的基因中更敏感地筛选克隆体细胞突变 AD 和控制大脑，这将使我们能够探索可能驱动的频繁突变基因或途径 该研究的第三个目标将集中于 AD 发病过程中载体细胞的克隆扩增。 不同细胞类型中潜在致病性体细胞突变的突变比例和功能影响 AD 大脑，特别是小胶质细胞，通过结合单细胞 RNA-seq 和 PRDD-seq（我们开发的一种方法） 用于对同一单细胞的体细胞突变和细胞类型信息进行并行分析。 研究将为体细胞突变对 AD 风险增加的贡献提供新的线索，并强调克隆 增殖相关基因体细胞突变引发的小胶质细胞扩张是一种潜在机制 AD 发病机制。