Notch1 and APP signaling in cerebral microvascular dysfunction

项目摘要/摘要 认知功能障碍和痴呆症是老年人面临的主要健康挑战，也是 脑部小血管疾病(CSVD)占全世界痴呆症患者总数的50%。分项数据 与CSVD相关的血管屏障和淋巴清除障碍被认为是早期的 人类认知功能障碍、皮质脑血流量减少和微血管渗漏的生物标志物 在痴呆症患者和小鼠模型的疾病发作期间观察。CSVD的一种分类， 淀粉样CSVD的特征是淀粉样β蛋白(Aβ)沉积增加，源于病理 淀粉样前体蛋白(APP)的蛋白分解处理，沿着和在脑微血管内。淀粉样蛋白 CSVD出现在几乎所有老年痴呆症患者和大约65%-85%的非痴呆症老年人中。 反过来，血液和淋巴微血管受损会破坏大脑对β的清除 微环境，加重Aβ沉积和CSVD病理。血液和淋巴微血管 淀粉样CSVD的功能障碍以血管内皮细胞-细胞的解体为特征 粘连及其主要介体--血管内皮细胞钙粘附素(VE-cadherin)。然而，分子 通过内皮细胞连接将β与血管和淋巴管通透性改变联系起来的机制 不稳定性和VE-钙粘附素的分解尚不清楚。最近，我们发现了一种新的机制，通过它 Notch1受体的蛋白降解过程是促进微血管屏障功能的关键 通过增强血管内皮细胞VE-钙粘附素连接。此外，我们的初步数据表明 Notch1和APP都需要与VE-钙粘素连接结合，才能被γ-分泌酶正确处理。 在这里，基于两个高度互补的实验室(Kutys和Jun)发现的机械性见解 实验室)，我们的研究团队将应用跨越生物尺度的工程和实验方法 单分子到3D人体仿生微血管来研究我们的中心假设 脑Aβ扰乱VE-钙粘蛋白连接处Notch1和/或APP处理的关键信号平衡 导致血液和淋巴微血管功能障碍。总之，这些研究将定义新的动态平衡 调节脑血液和淋巴微血管功能的机制，这些分子过程如何可能 被Aβ扰乱，并可能确定预防和治疗干预的新靶点。

Project Summary/Abstract Cognitive dysfunction and dementia are a major health challenge for the elderly and one of the primary underlying causes, cerebral small vessel disease (CSVD), contributes to 50% of all dementias worldwide. The breakdown of blood vascular barrier and impaired lymphatic clearance associated with CSVD are considered early biomarkers of human cognitive dysfunction, and reduced cortical cerebral blood flow and microvascular leak are observed during disease onset in both dementia patients and mouse models. One classification of CSVD, amyloidal CSVD, is characterized by the increased deposition of amyloid beta (Aβ), derived from the pathologic proteolytic processing of amyloid precursor protein (APP), along and within the brain microvasculature. Amyloidal CSVD appears in nearly all elderly patients with dementia and in roughly 65-85% of the elderly without dementia. Reciprocally, impaired blood and lymphatic microvasculature undermine Aβ clearance from the brain microenvironment, exacerbating Aβ deposition and CSVD pathology. Blood and lymphatic microvascular dysfunction during amyloidal CSVD are characterized by the disintegration of vascular endothelial cell-cell adhesions and their primary mediator, vascular endothelial cadherin (VE-cadherin). However, molecular mechanisms that link Aβ to changes in blood and lymphatic vessel permeability via endothelial cell junctional instability and VE-cadherin disassembly are unknown. Recently we have identified a novel mechanism by which the proteolytic processing of the Notch1 receptor is critical for the promotion of microvascular barrier function through the enhancement of endothelial VE-cadherin junctions. Additionally, our preliminary data suggest that both Notch1 and APP required association with VE-cadherin junctions for their proper processing by γ-secretase. Here, building upon mechanistic insights uncovered by two highly complementary laboratories (Kutys and Jun labs), our research team will apply engineering and experimental approaches that span biological scales from single molecules to 3D human biomimetic microvessels to investigate our central hypothesis that increased cerebral Aβ disrupts a critical signaling balance of Notch1 and/or APP processing at VE-cadherin junctions to drive blood and lymphatic microvascular dysfunction. Together, these studies will define new homeostatic mechanisms regulating brain blood and lymphatic microvascular function, how these molecular processes may be disrupted by Aβ, and potentially identify new targets for preventative and therapeutic intervention.