Impact of vascular apoE in aging and AD

项目概要（APOE U19：项目4） 虽然载脂蛋白E（apoE）的主要功能是介导脂质转运，但APOE基因型（APOE2， APOE3和APOE4）显著影响认知功能和阿尔茨海默病（AD）发病机制 通过多种途径。APOE不仅与β淀粉样蛋白（A β）病理学有关， 功能包括血脑屏障完整性和脑血流量。考虑到脑血管紊乱 apoE在老年人的认知能力下降中起重要作用，并且apoE在血管内皮细胞中大量表达。 壁细胞（平滑肌细胞和周细胞）以及脑中的星形胶质细胞和小胶质细胞， 项目4的目的是明确血管壁细胞中的APOE基因型如何影响分子机制， 在脑血管失调和认知能力下降的发展过程中，在老化和AD的途径。在 目的1，我们将利用新的小鼠模型，其中人APOE2、APOE3或APOE4基因在小鼠体内表达。 由血管壁细胞特异性sm22 α启动子驱动的Cre切除loxp侧翼的STOP盒 表达，以确定血管壁细胞特异性表达apoE亚型对 脑血管功能和脑认知功能的变化。在目标2中，我们将定义apoE亚型的影响， 血管壁细胞缺失对年龄相关性脑血管功能障碍和认知功能下降的影响 APOE基因敲入小鼠，其中鼠ApoE被floxed APOE2、APOE3或APOE4基因替换。通过 与sm22 α-Cre小鼠杂交，我们将特异性删除血管壁细胞中的单个apoE亚型。在aim中 3、我们将研究在条件性小鼠模型中，血管特异性表达或缺失apoE亚型 通过繁殖血管壁细胞特异性apoE同种型表达或敲除来影响AD相关表型 用淀粉样蛋白模型APP敲入小鼠（AppNL-F/NL-F）。使用这些独特的小鼠模型，我们将 全面研究血管壁细胞apoE亚型对脑血管功能、神经胶质细胞 表型、神经炎症、神经变性、脑认知和淀粉样病变。在 特别地，小鼠模型中的apoE特性将通过生物化学和结构分析来分析。 建模核心（核心B）。小鼠以及其他AD相关液体中的ApoE量、氧化和/或糖化 将通过生物标志物核心（核心D）测量生物标志物。虽然小鼠的神经病理学将 在神经病理学核心（核心C），包括蛋白质组学，代谢组学， 脂质组学和单细胞RNA测序将通过多组学核心（核心F）进行， 生物信息学，生物统计学和数据管理核心（核心G），以分析这些 小鼠模型。总之，我们的创新性研究应该填补了我们理解apoE是如何 脑血管系统中的同种型通过以下途径影响衰老和AD期间的细胞功能和脑内稳态： 与Core B-G的协同相互作用以及项目2和项目3的比较小鼠模型研究。

PROJECT SUMMARY (APOE U19: Project 4) While the major function of apolipoprotein E (apoE) is to mediate the lipid transport, APOE genotype (APOE2, APOE3 and APOE4) significantly influences cognitive function and Alzheimer’s disease (AD) pathogenesis through multiple pathways. APOE is associated with not only amyloid-β (Aβ) pathology but also cerebrovascular function including blood-brain barrier integrity and cerebral blood flow. Given that cerebrovascular disturbance substantially contributes to cognitive decline in the elderly and that apoE is abundantly expressed in vascular mural cells (smooth muscle cells and pericytes) as well as astrocytes and microglia in the brain, the overall goal of Project 4 is to define how APOE genotype in vascular mural cells impacts the molecular mechanisms and pathways in the development of cerebrovascular dysregulations and cognitive decline during aging and AD. In Aim 1, we will utilize novel mouse models, in which human APOE2, APOE3, or APOE4 gene is expressed upon an excision of a loxp-flanked STOP cassette by vascular mural cell specific sm22α promoter driven Cre expression to determine the effects of vascular mural cell-specific expression of apoE isoforms on cerebrovascular function and brain cognition during aging. In Aim 2, we will define the impact of apoE isoform deletion in vascular mural cells on age-related cerebrovascular dysfunction and cognitive decline using novel APOE knock-in mice, in which murine Apoe is replaced with floxed APOE2, APOE3, or APOE4 gene. By crossing with sm22α-Cre mice, we will specifically delete individual apoE isoforms in vascular mural cells. In Aim 3, we will examine how vascular-specific expression or deletion of apoE isoforms in conditional mouse models affects AD-related phenotypes by breeding the vascular mural cell-specific apoE isoform expressing or knockout mice with amyloid model APP knockin mice (AppNL-F/NL-F). Using those unique mouse models, we will comprehensively investigate how apoE isoforms in vascular mural cells impact cerebrovascular function, glial phenotypes, neuroinflammation, neurodegeneration, brain cognition and amyloid pathology at different ages. In particular, the apoE properties in the mouse models will be analyzed by the Biochemistry and Structural Modeling Core (Core B). ApoE amounts, oxidation and/or glycation in the mice as well as other AD-rerated fluid biomarkers will be measured through the Biomarker Core (Core D). While neuropathology in the mice will be investigated in Neuropathology Core (Core C), a multi-Omics approach including proteomics, metabolomics, lipidomics and single cell RNA sequencing will be carried out through the Multi-Omics Core (Core F) and Bioinformatics, Biostatistics, and Data Management Core (Core G) to profile molecular phenotypes in these mouse models. Together, our innovative study should fill a critical void in our understanding of how apoE isoforms in cerebrovasculature impact cellular functions and brain homeostasis during aging and AD through synergistic interaction with Core B-G and comparative mouse model studies by Project 2 and Project 3.