Understanding cellular architecture of the neurovascular unit and its function in the whole mouse brain

摘要 阿尔茨海默病（Alzheimer's disease，AD）是一种以认知功能下降为特征的疾病，尤其是对学习和记忆的影响 并且由于人口老龄化的加剧，已经成为突出的公共卫生问题。先前的研究 明确指出，有毒细胞废物（如淀粉样蛋白β（Aβ））的积累是主要的病理生理学因素， AD的标志。血管疾病，影响大脑清除代谢废物和供应能量的能力 神经元，长期以来一直与AD病理学有关。形成复杂网络的微血管 大的表面积作为血液供应和脑组织之间的主要界面。此外，周细胞鞘 微血管使它们能够调节血液流动和渗透性。新出现的证据表明， 微血管和周细胞的变性经常在AD患者和AD动物模型中观察到， AD.此外，AD中的Aβ积聚和血管网络变性发生在不同的脑区域， 在整个大脑中有不同的速率。虽然有强有力的证据表明Aβ与 无论微血管和周细胞损伤发生在AD之前， Aβ蓄积以及Aβ与微血管和周细胞的相互作用如何在不同时间段随时间变化 大脑区域仍不清楚。为了发现这一点并更全面地了解大脑区域的脆弱性， 我们需要检查这些行为的数量分布，以及它们对大脑功能的影响。 微血管和周细胞对Aβ损伤的影响与AD相关的行为改变有关。所以我们提出 一个两部分假设，以检查微血管和周细胞群体相关性的全脑变化 随着5xFAD小鼠中Aβ蓄积的出现。SA 1将重点放在假设，退化的 微血管发生在Aβ积聚和认知缺陷之前，而SA 2将检验一个假设， 随着疾病进展，周细胞变性先于Aβ积聚。这两种方法都将利用切割- 边缘清除和3D免疫标记，高分辨率光片荧光显微镜成像，以及先进的 计算分析以在AD小鼠模型中产生第一种血管/周细胞全脑图谱 进一步分析以解决微血管/周细胞与Aβ的相互作用，并结合行为测试 评估AD症状前和早期症状阶段的认知缺陷。

Abstract Alzheimer’s disease (AD) is characterized by steep cognitive decline especially affecting learning and memory and has become a prominent public health concern driven by an increasing aging population. Prior research pinpointed accumulations of toxic cellular wastes such as amyloid beta (Aβ) as a primary pathophysiological hallmark in AD. Vascular disorders, which affect the brain’s ability to clear metabolic wastes and supply energy to neurons, have long been implicated in AD pathology. Microvessels which form complex networks provide large surface areas as a main interface between blood supply and brain tissues. Moreover, pericytes ensheathe microvessels allowing them to regulate blood flow and permeability. Emerging evidence suggests that the degeneration of microvessels and pericytes has been frequently observed in AD patients and animal models of AD. Moreover, Aβ accumulation and degeneration of vascular networks in AD occur in different brain regions at different rates across the whole brain. While strong evidence of the harmful interactions between Aβ accumulation and neurovascular function in AD exists, whether microvessel and pericyte injury occurs prior to Aβ accumulation and how interactions of Aβ with microvessels and pericytes change over time across different brain regions remains unclear. To discover this and more fully understand brain regional vulnerabilities, temporal affectations, and their consequences to brain function, we need to examine the quantitative distribution of microvessels and pericytes upon Aβ insults in relation to AD related behavioral changes. Therefore, we propose a two part hypothesis to examine the brain-wide changes of microvessels and pericyte populations in correlation with the emergence of Aβ accumulation in 5xFAD mice. SA1 will focus on the hypothesis that degeneration of microvessels occurs prior to Aβ accumulation and cognitive deficit while SA2 will test a hypothesis that degeneration of pericytes precede Aβ accumulation as the disease progresses. Both methods will utilize cutting- edge clearing and 3D immunolabeling, high-resolution light sheet fluorescent microscopy imaging, and advanced computational analysis to generate a first of its kind vascular/pericyte whole brain atlas in an AD mouse model with further analysis to resolve the interactions of microvessels/pericytes with Aβ paired with behavioral testing to assess cognitive deficits at the presymptomatic and early symptomatic stages of AD.