Role of endothelium in pathogenesis of cerebral amyloid angiopathy

摘要 散发性脑淀粉样血管病(CAA)是一种由脑血管沉积引起的小血管疾病 淀粉样蛋白-β(Aβ)。CAA经常与阿尔茨海默病(AD)重叠，可能是因为Aβ是 被认为是AD病理学发展的主要罪魁祸首。重要的是，没有针对疾病的治疗方法。 可供CAA患者使用。与本项目相关的是，致病的分子机制 CAA是不完全理解的，从而限制了我们防止这种情况的开始和进展的能力 疾病。尽管CAA和CAA中血管性脑损伤的机制不同 阿尔茨海默病的神经退行性损伤，临床上，CAA与AD重叠，并与更严重的 阿尔茨海默病患者的认知损害此应用程序旨在推进在早期阶段 血管内皮源性Aβ在脑血管壁的沉积是其重要机制 与该病的发病机制有关。我们对培养的人类进行了广泛的初步研究 脑微血管内皮细胞(BMECs)、小鼠微血管和脑内皮细胞 荧光激活细胞分选(FACS)。使用下一代测序(RNA-Seq)来确定 人和小鼠脑血管内皮细胞的整体基因表达谱。转基因小鼠 并使用小鼠CAA实验模型来验证和扩展在培养的 人体内皮细胞。我们鉴定了以前未被识别的(非β依赖的)β位点的内皮功能 淀粉样前体蛋白(APP)裂解酶(BACE1)及其同系物(BACE2)。以下各项之间的一致性 在人和小鼠血管内皮细胞中的发现与BACE1的进化保守性很强一致 和BACE2。然而，当内皮BACE1对血管产生有害影响时，内皮BACE2 似乎是以前不为人知的非常重要的血管保护分子。进一步的初步调查 BACE1和BACE2在易感小鼠血管内皮细胞中的功能及信号转导分析 提示内皮细胞功能障碍的BACE1和BACE2促进Aβ在血管内皮细胞的沉积。 脑血管。根据这些初步发现，我们的工作假设是内皮细胞BACE1 BACE2在脑血管内稳态和CAA发病机制中起着重要作用。我们预料到 该项目的成功完成将为利用内皮细胞BACE1和BACE2作为 旨在预防CAA有害影响的治疗干预的分子靶点 脑血管和认知功能。

ABSTRACT Sporadic cerebral amyloid angiopathy (CAA) is a small vessel disease caused by cerebrovascular deposition of amyloid-β (Aβ). CAA frequently overlaps with Alzheimer’s disease (AD), presumably because Aβ is considered major culprit in development of AD pathology. Importantly, there is no disease-specific treatment available to patients with CAA. Relevant to this project, molecular mechanisms underlying pathogenesis of CAA are incompletely understood thereby limiting our ability to prevent initiation and progression of this disease. Despite mechanistic differences between vascular-induced brain injury in CAA and neurodegenerative injury in AD, clinically, CAA overlaps with AD and it is associated with more severe cognitive impairment in AD patients. This application is designed to advance the concept that in early stages of CAA, deposition of endothelium-derived Aβ in cerebral blood vessel wall is an important mechanism contributing to pathogenesis of the disease. We performed extensive preliminary studies on cultured human brain microvascular endothelial cells (BMECs), mouse microvessels, and brain endothelial cells isolated by fluorescence activated cell sorting (FACS). Next generation sequencing (RNA-Seq) was used to determine global gene expression profiles in human and murine cerebrovascular endothelium. Genetically modified mice and a murine experimental model of CAA were used to validate and expand observations obtained in cultured human endothelium. We identified previously unrecognized (Aβ-independent) endothelial functions of β-site amyloid precursor protein (APP)-cleaving enzyme (BACE1) and its homologue (BACE2). Consistency between findings in human and murine endothelium was in agreement with strong evolutionary conservation of BACE1 and BACE2. However, while endothelial BACE1 exerts detrimental vascular effects, endothelial BACE2 appears to be previously unrecognized and very important vascular protective molecule. Further preliminary analyses of BACE1 and BACE2 function and signaling in endothelium of mice vulnerable to development of CAA, suggested that dysfunctional BACE1 and BACE2 in endothelium promote elevated Aβ deposition in the cerebral blood vessels. Based on these preliminary findings our working hypothesis is that endothelial BACE1 and BACE2 play distinct roles in cerebrovascular homeostasis and pathogenesis of CAA. We anticipate that successful completion of this project will offer new opportunities to utilize endothelial BACE1 and BACE2 as molecular targets for therapeutic interventions designed to prevent detrimental effects of CAA on cerebrovascular and cognitive function.