Atlas for neuronal and glial cell types selectively vulnerable to proteinopathies during progression of Alzheimer's Disease

摘要 该项目的长期目标是阐明选择性脆弱性的多模式机制， 在阿尔茨海默病（AD）的进展过程中，神经元和非神经元细胞发生蛋白质病。的 AD最显著的特征是其显著的年龄和性别依赖性区域发病和进展选择性 可移植性-其表现在不同的临床表现中，例如，AD的记忆障碍和 大脑退化最近对AD神经病理学分期的研究表明，AD相关的tau蛋白病开始于 在蓝斑（LC），其次是内嗅皮层（EC）的神经纤维缠结，然后是 海马（HC），然后是新皮质，例如，前额叶皮层（PFC）。选择性脆弱性的一个假设 主要的AD风险基因受区域限制，但结果显示它们的表达相当广泛。一 大量证据支持胶质细胞在AD发病机制中发挥着多种重要作用。 这些数据表明，选择性脆弱性可能是神经元内在特性相互作用的结果 和神经胶质细胞对蛋白质病的反应，在脆弱的大脑中以动态和时空的方式 地区例如，EC神经元投射多个大脑区域，包括EC、PFC和小脑。然而， EC和PFC的退化发生在不同的阶段。相比之下，小脑基本上不受影响。 有新的证据表明，小胶质细胞的亚群处理兴奋性和抑制性神经元不同。 不同的神经胶质细胞类型或对不同投射来源的蛋白质病变的不同反应和/或 目标有助于选择性脆弱性？这些结果强调了理解的核心重要性 细胞类型的多样性和分子标记的差异，在两性在时空，单细胞 脆弱和不太脆弱的神经元和神经胶质细胞群体之间的分辨率和多模式量表 易患AD中的蛋白质病。显示Tau和Aβ的MAPTS 305 N; Int 10 +3和APPNL-F敲入（KI）AD小鼠 蛋白质病将分别用于实现这一目标。获得的初步结果支持 项目首先，对照组中的条形码单神经元全脑投射映射显示了性别和年龄， LC神经元对选择性靶点的投射存在依赖性差异。结果显示， 这四个脑区之间的神经支配。第二，分析16月龄对照和APPNL-F小鼠 去甲肾上腺素（NE）神经元显示异常的神经支配模式。第三，前脉冲抑制受损 (PPI)已被认为是前驱AD的生物标志物。重要的是，观察到PPI受损， 5个月大的APPNL-F小鼠。最后，使用来自16月龄对照和16月龄对照的EC的单核（sn）-RNAseq， APPNL-F小鼠表现出神经元和非神经元细胞类型的选择性丢失以及一系列蛋白质的差异表达。 基因，包括那些与神经元和神经胶质功能和受损的PPI。Sn-转录组学 和表观基因组学将被用来识别脆弱的细胞类型，然后用空间转录组学来识别脆弱的细胞类型， 研究蛋白质病与脆弱细胞类型和基因网络之间的时空相关性。

Abstract The long-term goal of this project is to elucidate multimodal mechanisms underlying selective vulnerability of neuronal and non-neuronal cells to proteinopathies during the progression of Alzheimer's Disease (AD). The most notable feature of AD is its strikingly age- and sex-dependent regional onset and progression–selective vulnerability–which is manifest in distinct clinical presentations, e.g., memory impairment in AD and patterns of brain degeneration. Recent studies on the staging of AD neuropathology showed AD-related tauopathy begins in the locus coeruleus (LC), followed by neurofibrillary tangles in the entorhinal cortex (EC), followed by hippocampal (HC), and then neocortex, e.g., prefrontal cortex (PFC). One hypothesis for selective vulnerability is that major AD risk genes are regionally restricted, but the results show they are rather broadly expressed. A body of evidence support that glia play multiple essential roles at different brain region in AD pathogenesis. These data suggest that selective vulnerability is likely a result of interplay of intrinsic properties of neurons and glial cells in their response to proteinopathies in a dynamic and spatiotemporal manner at vulnerable brain regions. For example, EC neurons project multiple brain regions including the EC, PFC and cerebellum. Yet, degeneration of EC and PFC occurs at different stages. In contrast, the cerebellum is largely not affected. There is emerging evidence that subpopulations of microglia treat excitatory and inhibitory neurons differently. Could different glial cell types or differential response to proteinopathies in different projecting sources and/or targets contribute to selective vulnerability? These results underscore the central importance of understanding the diversity of cell types and molecular signature differences in both sexes at spatiotemporal, single-cell resolution and multimodal scales between vulnerable and less vulnerable neuronal and glial populations susceptible to proteinopathies in AD. MAPTS305N;Int10+3 and APPNL-F knock-in (KI) AD mice displaying Tau and Aβ proteinopathies, respectively, will be used to achieve this goal. Preliminary results were obtained to support the project. First, barcoded single-neurons brain-wide projection mapping in controls demonstrates sex- and age- dependent differences in projections of LC neurons to selective targets. The results showed reciprocal innervations among these four brain regions. Second, the analysis of 16-month-old control and APPNL-F mice showed aberrant innervation patterns by norepinephrine (NE) neurons. Third, impaired prepulse inhibition (PPI) has been suggested to be a biomarker for prodromal AD. Importantly, PPI impairment was observed in the 5-month-old APPNL-F mice. Finally, single nuclei (sn)-RNAseq of the EC from 16-month-old control and APPNL-F mice showed selective loss of neuronal and non-neuronal cell types and differential expression of a list of genes, including those associated with neuronal and glial function and impaired PPI. Sn-transcriptomics and-epigenomics will be employed to identify vulnerable cell types followed by spatial transcriptomics to investigate spatiotemporal correlation between proteinopathies and vulnerable cell types and gene networks.