TYROBP/DAP12: a hub protein linking Alzheimer's disease, microglia, and gut microbiome.

摘要 最近的遗传学和基因组学方法已经集中在小胶质细胞和炎症在糖尿病中的作用上。 阿尔茨海默病(AD)的发病机制，可能为开发预防措施提供新的机会 和/或治疗阿尔茨海默病。在一项多尺度基因网络分析中，伊坎医学院的一个研究小组 在西奈山，TYROBP(又名DAP12)被认为是小胶质细胞激活和AD的关键驱动基因 发病机制。TYROBP是首批从综合多尺度方法中涌现的零星事件之一 AD构成了AMP-AD加速AD药品伙伴关系(AD)计划的基础。我们以前的 对APP/PS1小鼠AD病理模型的研究表明，TYROBP在mRNA或蛋白质水平上的减少 其活性的水平或抑制可代表通过以下方式预防或治疗AD的潜在治疗靶点 抑制内环境平衡型小胶质细胞C1q的表达及参与开关相关基因的诱导 到与疾病相关的小胶质细胞。肠道微生物区系也被认为是小胶质细胞活动的调节器。 和淀粉样变性病理。这项研究的总体目标是阐明肠道TYROBP的作用 微生物区系，以及它们对脑生理和AD调节的相互作用。我们建议两个 目标相辅相成。首先，我们将确定TYROBP和肠道微生物区系在 脑转录组在生理性衰老或淀粉样蛋白发生发展过程中的调节 病理学。我们将进行RNA测序，并比较WT和APP/PS1小鼠的转录图谱 它们分别是Tyrobp基因座上的WT或KO，以及(A)正常的肠道菌群 丰度，(B)丰度降低的正常肠道菌群，或(C)模仿菌群的病理性肠道微生物区系 在小鼠AD肠道中鉴定。使用16S rRNA测序，我们将识别细菌种群的变化 肠道微生物区系相关的动作和TYROBP水平的调节，并将试图建立一个原因 肠道微生物区系和免疫Tyrobp调节的转录组之间的联系。第二，我们将定义如何 TYROBP水平与肠道微生物区系相互作用，以及这些变量如何反过来调节AD表型和 小胶质细胞激活。我们将进行一组行为和生化分析，以确定 无论是调节肠道微生物区系的水平和/或类型、TYROBP表达水平，还是以下各项的组合 两者均可导致小胶质细胞活性改变和AD发病机制。 这项研究的预期结果是产生重要的新的实验结果，将阐明 微生物区系调控小胶质细胞激活与阿尔茨海默病的作用及机制该项目还将生成 确定不同类型、水平和比例的肠道细菌的调节是否可以 调节TYROBP的活动，并形成旨在减缓或预防AD的临床干预的基础。

ABSTRACT Recent genetic and genomic approaches have converged on the role of microglia and inflammation in the pathogenesis of Alzheimer’s disease (AD), potentially presenting novel opportunities for developing prophylaxis and/or therapeutics against AD. In a multiscale gene network analysis, a group at the Icahn School of Medicine at Mount Sinai highlighted TYROBP (aka DAP12) as a key driver gene in microglia activation and AD pathogenesis. TYROBP is one of the first “hits” to emerge from the integrative multi-scale approach to sporadic AD that forms the basis for the AMP-AD Accelerating Medicines Partnership in AD) Program. Our previous studies in the APP/PS1 mouse model of AD pathology suggest that reduction of TYROBP at the mRNA or protein level or inhibition of its activity could represent a potential therapeutic target for AD prevention or treatment by repressing the expression of C1q and the induction of genes involved in the switch from homeostatic microglia to disease-associated microglia. Gut microbiota have also been advanced as a modulator of microglial activity and amyloid pathology. The overall goal of this study is to elucidate the role of TYROBP, the gut microbiota, and their interaction on the regulation of brain physiology and AD. We propose two complementary aims. First, we will identify the role and interaction of TYROBP and the gut microbiota on the regulation of the brain transcriptome during physiological aging or during the onset and progression of amyloid pathology. We will perform RNA sequencing and compare the transcriptomic profiles of WT and APP/PS1 mice that are, respectively either WT or KO at the Tyrobp locus and that harbor either (a) normal gut flora in normal abundance, (b) normal gut flora in reduced abundance or (c) pathological gut microbiota mimicking the flora identified in mouse AD gut. Using 16S rRNA sequencing, we will identify changes in bacterial populations due to gut microbiota-related maneuvers and modulation of TYROBP levels and will attempt to establish a causal link between gut microbiota and the immune-Tyrobp regulated transcriptome. Second, we will define how TYROBP level interacts with the gut microbiota, and how, in turn, these variables modulate AD phenotype and microglia activation. We will perform a panel of behavioral and biochemical analyses in order to determine whether modulation of levels and/or types of gut microbiota, TYROBP expression levels, or the combination of both result in changes in microglial activity and AD pathogenesis. The expected outcome of this study is to generate important novel experimental results that will elucidate the role and the mechanisms of microbiota regulation of microglia activation and AD. This project will also generate important data to determine whether the modulation of different types, levels, and ratios of gut bacteria could modulate TYROBP activity and form the basis for clinical interventions aimed at slowing or preventing AD.