Examining the role of perivascular fibroblasts in cerebral amyloid angiopathy during Alzheimers disease

摘要 阿尔茨海默病(AD)是一种使人衰弱的慢性神经退行性疾病，是最常见的 痴呆症。阿尔茨海默病的病理生理学包括神经元和突触的进行性丢失。 大脑皮层和皮质下区域，以淀粉样β蛋白(Aβ)斑块堆积为特征 和含有tau的神经原纤维缠绕在这些区域的病理中。据报道，一种β斑块 与神经元和神经胶质细胞(实质斑块)有关，或与血管有关 (血管斑块称为脑淀粉样血管病[CAA])。高达90%的AD患者存在CAA， 被认为会导致血液流动障碍，血管形态改变，炎症，微出血和 大出血。尽管CAA很重要，但人们对Aβ如何在船舶周围沉积知之甚少。 有两个主要假设：第一，血管斑块是通过Aβ的异常分泌而产生的 内皮细胞和/或壁细胞。第二，血管斑块是通过清除功能障碍而产生的 一个β的人。在这里，我们检验了一个新的假说：血管周围成纤维细胞在CAA的产生中分泌Aβ。在.工作 本实验室已发现AD患者血管周围成纤维细胞与血管Aβ斑块密切相关 尸检组织。我们还发现血管周围成纤维细胞强烈表达淀粉样蛋白。 前体蛋白(APP)和处理淀粉样蛋白的酶(BACE1/2，PSEN1)。在这里，我们将使用 条件基因敲除方法确定成纤维细胞是否是分泌Aβ的关键细胞类型 在特征良好的阿尔茨海默病小鼠模型中产生CAA。我们还将利用单细胞测序来 研究血管周围成纤维细胞的细胞异质性和基因表达随时间的变化 小鼠AD模型。如果我们发现血管周围成纤维细胞是Aβ分泌的关键贡献者 那么，这一分析将有助于深入了解导致这种血管Aβ积聚的机制。 如果我们发现成纤维细胞分泌的Aβ对于CAA的产生并不是必需的，这项分析将提供 关于成纤维细胞如何在血管Aβ斑块形成过程中发生变化的重要信息 是密切相关的。

ABSTRACT Alzheimer's disease (AD) is a debilitating, chronic neurodegenerative disease that is the most common form of dementia. The pathophysiology of AD includes the progressive loss of neurons and synapses throughout the cerebral cortex as well as subcortical regions, and is characterized by the buildup of amyloid-beta (Aβ) plaques and tau-containing neurofibrillary tangle pathologies throughout these regions. Aβ plaques have been reported to be associated with neuronal and glial cells (parenchymal plaques), or associated with blood vessels (vascular plaques termed cerebral amyloid angiopathy [CAA]). CAA is found in up to 90% of patients with AD, and is thought to lead to impaired blood flow, altered vascular morphology, inflammation, microbleeds and hemorrhage. Despite the importance of CAA, very little is known about how Aβ deposits around vessels. There are two main hypotheses: First, vascular plaques are generated through the aberrant secretion of Aβ by endothelial cells and/or mural cells. Second, vascular plaques are generated though dysfunction in clearance of Aβ. Here we test a novel hypothesis: perivascular fibroblasts secrete Aβ in the generation of CAA. Work in our lab has identified that perivascular fibroblasts are intimately associated with vascular Aβ plaques in AD postmortem tissue. We have also identified that that perivascular fibroblasts robustly express amyloid precursor protein (APP) and the enzymes that process amyloid (BACE1/2, PSEN1). Here, we will use a conditional knockout approach to determine whether fibroblasts are the key cell type that secretes Aβ in the generation of CAA in a well characterized mouse model of AD. We will also utilize single cell sequencing to examine the cellular heterogeneity and gene expression of the perivascular fibroblasts as a function of time in the mouse AD model. If we find that perivascular fibroblasts are key contributors to Aβ secretion in the buildup of CAA, then this analysis will give insights into to the mechanism that leads to this vascular Aβ accumulation. If we find that fibroblast secretion of Aβ is not necessary for the generation of CAA, this analysis will provide vital information about how the fibroblasts change during the formation of vascular Aβ plaques, with which they are intimately associated.