Exploring Blood-Brain Barrier Dysfunction in Alzheimer's Disease

摘要 阿尔茨海默病(AD)是一种使人衰弱的神经系统疾病，也是导致痴呆的主要原因。这个 阿尔茨海默病的病理生理学包括神经元丢失，其特征是淀粉样斑块和 神经原纤维缠结，导致对这些疾病过程的广泛研究。最近，有证据表明 提示血脑屏障(BBB)功能障碍可能与AD的进展和严重程度有关。 然而，阿尔茨海默病患者血脑屏障功能障碍的机制尚不清楚。BBB起到了信号的作用 血液和大脑之间的运输接口，具有极低的通透性和丰富的分子 在运输系统中，血脑屏障帮助调节脑细胞外液。而脑内皮细胞 在调节这些血脑屏障功能的过程中，血脑屏障很大程度上受到内皮细胞与支持细胞相互作用的影响 神经血管单位(NVU)，包括星形胶质细胞、周细胞和神经元。目前还不清楚是哪一种 人类的血脑屏障功能在AD中受到影响，是什么导致了这些血脑屏障的变化，以及哪些NVU细胞类型 负责任。阿尔茨海默病的血脑屏障功能障碍可能是由遗传因素引起的，如载脂蛋白E等位基因，这是AD的主要风险 因素，或可能是次要的神经退行性疾病过程。在这份提案中，我们将调查这两个 可能性。首先，通过部署一种强大的创新方法来模拟人类疾病，使用 诱导多能干细胞(IPSC)技术，我们将研究载脂蛋白E等位基因对血脑屏障功能的影响。 我们最近已经证明，从患者身上提取每一种关键的NVU细胞类型是可能的- 这些模型可以用来更好地理解人类遗传性血脑屏障功能障碍 疾病。在这里，IPSC衍生的NVU模型将被用于研究ApoE等位基因组合，以确定 它们对血脑屏障、运输和免疫功能的影响，并确定推动NVU的关键细胞类型 观察到的效果。接下来，为了研究血脑屏障功能障碍是疾病过程的次要因素的可能性， 我们将鉴定人AD脑内皮细胞的分子变化，然后检测它们在 IPSC派生的NVU型号。将从AD患者的脑组织中分离出脑内皮细胞，并将其状态 用于鉴定AD脑中差异丰富的蛋白质的最先进的多重蛋白质组学方法 内皮细胞。然后，我们将使用基因编辑技术来创建IPSC系，在其中我们可以调制 差异调控基因的表达及其对血脑屏障功能的影响 多细胞IPSC衍生的NVU模型。更好地了解老年人血脑屏障功能障碍的来源和形式 AD将产生对AD疾病进展的新的机械性见解，并为治疗提供新的途径 干预。

ABSTRACT Alzheimer’s disease (AD) is a debilitating neurological disease and the leading cause of dementia. The pathophysiology of AD includes neuronal loss and is characterized by the buildup of amyloid plaques and neurofibrillary tangles, leading to extensive study of these disease processes. Recently, evidence has suggested that blood-brain barrier (BBB) dysfunction may contribute to the progression and severity of AD. However, the mechanisms of BBB dysfunction in AD remain to be elucidated. The BBB acts as a signaling and transport interface between the blood and brain, and with its very low permeability and a wealth of molecular transport systems, the BBB helps regulate the extracellular fluid of the brain. While brain endothelial cells mediate these BBB functions, the BBB is greatly influenced by endothelial cell interactions with supporting cells of the neurovascular unit (NVU), including astrocytes, pericytes and neurons. Currently, it is unclear which human BBB functions are affected in AD, what causes these BBB changes, and which NVU cell types are responsible. BBB dysfunction in AD could be caused by genetic factors such as ApoE allele, a major AD risk factor, or may be secondary to neurodegenerative disease processes. In this proposal, we will investigate both possibilities. First, by deploying a powerful and innovative approach for modeling human disease using induced pluripotent stem cell (iPSC) technology, we will investigate the impact of ApoE allele on BBB function. We have recently demonstrated that it is possible to derive each of the key NVU cell types from patient- sourced iPSCs, and that these models can be used to better understand BBB dysfunction in genetic human disease. Here, the iPSC-derived NVU model will be used to investigate ApoE allele combinations to determine their effects on BBB barrier, transport and immune functions and to identify the key NVU cell type driving the observed effects. Next, to investigate the possibility that BBB dysfunction is secondary to disease processes, we will identify the molecular changes in human AD brain endothelial cells and then examine their function in the iPSC-derived NVU model. Brain endothelial cells will be isolated from brain tissue of AD patients and state- of-the-art multiplex proteomic methods used to identify proteins that are differentially abundant in AD brain endothelium. We will then use gene editing techniques to create iPSC lines in which we can modulate expression of the differentially regulated genes and evaluate their effects on BBB function using the multicellular iPSC-derived NVU model. A better understanding of the sources and forms of BBB dysfunction in AD will yield new mechanistic insights into AD disease progression, and suggest new avenues for therapeutic intervention.