THE ROLE OF ZFYVE21 IN CEREBRAL AMYLOID ANGIOPATHY IN ALZHEIMER'S DISEASE

项目总结 脑淀粉样血管病(CAA)是一种无法治疗的血管病变，影响绝大多数 阿尔茨海默病(AD)患者。在CAA中，Aβ(1-40)的纤维沉积在脑血管中，并促进 发生狭窄病变、颅内出血和血管周围炎症。这些CAA- 相关的血管病变与AD的严重程度有很强的线性相关性，因此被认为 促进神经退行性变，导致AD痴呆。CAA是如何发展的，目前还知之甚少 明确其发病机制(S)将为AD的血管治疗提供新的策略。 补体(C‘)是参与宿主防御的一种保守的血浆蛋白系统。在激活后， C‘蛋白质自组装成称为膜攻击复合体(MAC)的异二聚体结构 随着跨膜毛孔进入靶细胞膜。MAC与CAA中的Aβ(1-40)存款共存- 受影响的血管有证据表明EC激活，并抑制补体蛋白C5，从而防止 Mac组装，在CAA小鼠模型中阻止AD的进展。在实体器官移植中， 我们确定ZFYVE21是一种新的由MAC诱导的Rab5效应器，它激活了非规范的NF-κB，NLRP3 炎性小体和规范的NF-κB介导内皮细胞(EC)的激活和发展 血管病变。由于在CAA中观察到C‘激活、EC激活和类似形式的血管病变， 我们探讨了ZFYVE21信号是否在这种情况的发生发展中发挥了作用。 因此，我们开始了基于假设的研究，定义了ZFYVE21信号在CAA中的作用 Aβ纤维激活脑血管内皮细胞表面C‘诱导ZFYVE21介导的EC活化促进CAA 阿尔茨海默病的血管病变和CAA相关的神经变性。AD活组织检查显示MAC染色很强， ZFYVE21及其在Aβ载药微血管中的下游通路。发展机制(S) 为了解释这些发现，我们优化了β诱导的C‘激活的体外模型，该模型足够健壮 证实ZFYVE21在人脑血管内皮细胞(HBMECs)中介导的信号转导。我们开发了 用新的体外和体内模型系统检测ZFYVE21信号的功能意义 与EC激活、屏障通透性和巨噬细胞募集有关。在三个统一的目标中，我们将延伸 我们最初提出的研究ZFYVE21介导的CAA中EC激活机制的发现。我们的 AIMS将成为一项长期计划的基础，该计划将投资于研究C‘如何介导血管病理 阿尔茨海默病的进一步神经退行性变。

PROJECT SUMMARY Cerebral amyloid angiopathy (CAA) is an untreatable vasculopathic condition affecting a vast majority of patients with Alzheimer's disease (AD). In CAA, fibrils of Aβ(1-40) deposit in cerebral vessels and promote the development of stenotic lesions, intracranial hemorrhages, and perivascular inflammation. These CAA- associated vascular pathologies show strong linear correlations with the severity of AD, and are thus believed to promote neurodegeneration and contribute to AD dementia. How CAA develops is poorly understood and defining mechanism(s) related to its pathogenesis will define new vascular-based strategies for treating AD. Complement (C') are a conserved system of plasma proteins involved in host defense. Upon activation, C' proteins self-assemble into heterodimeric structures called membrane attack complexes (MAC) that insert as transmembranous pores into target cell membranes. MAC colocalize with Aβ(1-40) deposits in CAA- affected vessels showing evidence of EC activation, and inhibition of complement protein C5, which prevents MAC assembly, blocks progression of AD in a murine mouse model with CAA. In solid organ transplantation, we identified ZFYVE21 as a novel MAC-induced Rab5 effector that activated non-canonical NF-κB, NLRP3 inflammasomes, and canonical NF-κB to mediate endothelial cell (EC) activation and development of vasculopathic lesions. As C' activation, EC activation, and similar forms of vasculopathy are observed in CAA, we explored whether ZFYVE21 signaling may play a role in the development of this condition. We thus embarked on studies defining a role for ZFYVE21 signaling in CAA based on the hypothesis Aβ fibrils activate C' on cerebrovascular ECs to induce ZFYVE21-mediated EC activation to promote CAA vasculopathy and CAA-related neurodegeneration in AD. AD biopsies showed strong staining for MAC, ZFYVE21, and its downstream pathways in Aβ-laden microvessels affected by CAA. To develop mechanism(s) to explain these findings, we optimized an in vitro model of Aβ-induced C' activation that was sufficiently robust to confirm ZFYVE21-mediated signaling in human cerebrovascular endothelial cells (HBMECs). We developed new in vitro and in vivo model systems to examine the functional significance of ZFYVE21 signaling with regards to EC activation, barrier permeability, and macrophage recruitment. In 3 unified aims, we will extend findings from our original proposal to investigate ZFYVE21-mediated mechanisms of EC activation in CAA. Our aims will form the basis for a long-term program invested in studying how C' mediates vascular pathologies to further neurodegeneration in AD.