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存在选择性脆弱性的多模式机制。 阿尔茨海默病(AD)进展过程中神经细胞和非神经细胞对蛋白质病变的影响。这个 阿尔茨海默病最显著的特征是其显著的年龄和性别依赖性的区域性发病和进展选择性 脆弱性--表现在不同的临床表现上，例如，AD的记忆障碍和 脑部退化。最近关于AD神经病理学分期的研究表明，AD相关的肌萎缩症开始 在蓝斑(LC)，然后是内嗅皮层(EC)的神经原纤维缠绕，然后是 海马(HC)，然后是新皮质，如前额叶皮质(PFC)。选择性脆弱性的一个假设 主要的阿尔茨海默病风险基因是区域性受限的，但结果表明它们的表达相当广泛。一个 大量证据支持胶质细胞在AD发病机制中不同脑区发挥多种重要作用。 这些数据表明，选择性易损性很可能是神经元固有特性相互作用的结果 在脆弱的大脑中，胶质细胞以动态和时空的方式对蛋白质病做出反应 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，小脑在很大程度上没有受到影响。 有新的证据表明，小胶质细胞亚群对兴奋性神经元和抑制性神经元的处理方式不同。 不同的胶质细胞类型或对不同投射来源和/或蛋白质病的不同反应 目标会导致选择性的脆弱性吗？这些结果强调了理解 单细胞时空中两性细胞类型的多样性和分子特征差异 脆弱和较不脆弱的神经元和神经胶质细胞群体之间的分辨率和多峰标度 在阿尔茨海默病中易患蛋白质病。表现Tau和Aβ的MAPTS305N；Int10+3和APPNL-F敲入(Ki)AD小鼠 蛋白质疗法将分别用于实现这一目标。获得的初步结果支持了 项目。首先，对照组的条形码单神经元全脑投影图显示了性别和年龄-- LC神经元对选择性靶点投射的依赖差异。结果表明，这两种方法是互惠的 这四个脑区之间的神经联系。16月龄对照组和APPNL-F小鼠的分析 去甲肾上腺素(NE)神经元表现出异常的神经支配模式。第三，脉冲前抑制功能受损 (PPI)被认为是前驱AD的生物标志物。重要的是，PPI损害观察到在 5个月大的APPNL-F小鼠。最后，16个月龄对照的EC的单核(SN)-RNAseq和 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List的差异表达 基因，包括那些与神经元和神经胶质功能相关的基因和受损的PPI。SN-转录组学 和表观基因组学将被用来鉴定脆弱的细胞类型，然后是空间转录组学 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.