VCAM1 in brain endothelial cell activation in aging and Alzheimer's disease

VCAM1 在衰老和阿尔茨海默病中脑内皮细胞激活中的作用

基本信息

批准号：
10327269
负责人：
Nathalie Khoury
金额：
$ 1.94万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-15 至 2021-08-13
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10327269
关键词：
Ablation Adhesions Aging Alzheimer&apos s Disease Alzheimer&apos s disease model Alzheimer&apos s disease pathology Alzheimer&apos s disease patient Antibodies Automobile Driving Binding Blood Blood - brain barrier anatomy Brain Cell Adhesion Cells Cerebrovascular system Cerebrum Cognitive Cognitive deficits Cues Dementia Deterioration Disease Encephalitis Endothelial Cells Exhibits Extravasation Gene Expression Genes Genetic Hippocampus (Brain)Immune Impairment In Vitro Inflammation Inflammatory Integrin alpha4beta1 Knock-out Knockout Mice Knowledge Ligands Mass Spectrum Analysis Measures Mediating Mediator of activation protein Membrane Microglia Mus Neurodegenerative Disorders Pathologic Pathway interactions Patients Plasma Predisposition Proteins Proteomics Risk Role Senile Plaques Severities Side Signal Pathway Signal Transduction Structure Testing Tissues Transgenic Mice Vascular Cell Adhesion Molecule-1 Venous Virus Work age effect age related aged aging brain aging population base blood-brain barrier permeabilization brain endothelial cell cerebrovascular cognitive function effective therapy experimental study improved in vitro Model in vivo in vivo Model inflammatory marker mouse model mutant nerve stem cell nervous system disorder neurogenesis neutralizing antibody new therapeutic target normal aging novel overexpression response single-cell RNA sequencing therapeutic target transcriptomics

项目摘要

Aging leads to the decline of brain structure and function which increases the susceptibility to neurodegenerative disorders. Work from the Wyss-Coray lab support a cell non-autonomous and reversible mechanism of brain aging regulated by the systemic milieu. Aged plasma drives brain aging in young mice as shown by the reduction in hippocampal neurogenesis, increase in microglia reactivity, and decline in cognitive functions. While young plasma reverses these hallmarks in aged mice. As the identity of the pro-youthful and pro-aging factors is being revealed, it remains unclear how they signal into the brain across the highly impermeable blood brain barrier. Recent work from our lab revealed that aged plasma upregulates on brain endothelial cells (BEC) the expression of an adhesion protein VCAM1 (Vascular Cell Adhesion Molecule 1), which also increases during normal aging. The genetic ablation of VCAM1 from BECs or its neutralization with a systemic antibody abolishes the effects of aged plasma and reverses hallmarks of brain aging. This supports a crucial role for VCAM1 as a mediator of age-related circulatory cues. Yet it remains unclear how VCAM1 alters BECs to drive brain aging. At a single cell level, VCAM1 expressing BECs exhibit a high inflammatory profile compared to VCAM1 negative BECs and blocking VCAM1 reduces brain inflammation suggesting that it may induce the inflammatory signaling in BECs. In addition to aging, VCAM1 increases in the cerebral vessels of Alzheimer’s disease (AD) mice and colocalizes with amyloid plaques and reactive microglia. Soluble VCAM1 also increases in AD patient plasma and highly correlates with dementia severity and pathological hallmarks of AD. Based on these combined observations, this proposal will test the hypothesis that increased VCAM1 disrupts brain endothelial cell signaling during aging and promotes AD-like disease in mice. Aim 1 will determine whether VCAM1 induces the expression of inflammatory genes in aged BEC using single cell transcriptomic analysis of hippocampal BECs and proteomic analysis of microvessels. Experiments will be performed using aged mice where VCAM1 is genetically ablated from BECs or neutralized with an antibody and using young mice where VCAM1 is overexpressed in BEC using the AAV2- BR1 virus. Aim 2 will identify the mechanism behind which VCAM1 signals to induce BEC activation. Primary BECs overexpressing wild-type or mutant VCAM1 will be cultured in the presence or absence of the VCAM1 ligand VLA-4 (very late antigen-4) to determine its effect on the expression of inflammatory genes in BEC. Mutant VCAM1 that shows the highest reduction in BEC activation will be introduced in vivo using the AAV2-BR1 virus to assess microglia reactivity and neural stem cell activity. Aim 3 will determine the role of VCAM1 in a mouse model of AD. VCAM1 neutralizing antibody will be systemically introduced to determine its effect on amyloid plaques, reactive microglia, cognitive deficits, and the activation of BECs as measured by transcriptomic analysis of inflammatory genes. This project will identify aging-induced inflammatory pathways altered by VCAM1 in BECs along with its mechanism of signaling, and determine the potential of VCAM1 as a therapeutic target for AD.

衰老导致大脑结构和功能衰退，从而增加神经退行性疾病的易感性 Wyss-Coray 实验室的工作支持大脑的细胞非自主和可逆机制。衰老受全身环境调节，老化血浆会导致年轻小鼠的大脑衰老，如减少所示。年轻时海马神经发生、小胶质细胞反应性增加和认知功能下降。血浆逆转了老年小鼠的这些特征，因为促年轻和促衰老因子的身份正在被确定。据透露，目前尚不清楚它们如何通过高度不渗透的血脑屏障向大脑发出信号。我们实验室最近的工作表明，老化血浆上调脑内皮细胞 (BEC) 的表达粘附蛋白 VCAM1（血管细胞粘附分子 1）的含量在正常衰老过程中也会增加。 BEC 中 VCAM1 的基因消除或用全身性抗体中和可消除以下因素的影响：衰老的血浆并逆转大脑衰老的特征，这支持了 VCAM1 作为大脑衰老调节因子的关键作用。然而，目前尚不清楚 VCAM1 如何改变 BEC 来驱动大脑衰老。水平，与 VCAM1 阴性 BEC 相比，表达 VCAM1 的 BEC 表现出较高的炎症特征，阻断 VCAM1 可减少脑部炎症，表明它可能会诱导 BEC 中的炎症信号传导。除了衰老之外，阿尔茨海默病 (AD) 小鼠的脑血管中的 VCAM1 也会增加，并共定位 AD 患者血浆中的淀粉样斑块和反应性小胶质细胞也增加。根据这些综合观察结果，这与痴呆的严重程度和 AD 的病理特征相关。该提案将检验以下假设：VCAM1 增加会在衰老和衰老过程中破坏脑内皮细胞信号传导促进小鼠 AD 样疾病目标 1 将确定 VCAM1 是否诱导炎症表达。使用海马 BEC 的单细胞转录组分析和蛋白质组分析分析老年 BEC 中的基因实验将使用老年小鼠进行，其中 VCAM1 从 BEC 中被基因消除。或用抗体中和并使用年轻小鼠，其中 VCAM1 在 BEC 中使用 AAV2- 过表达 BR1 病毒。目标 2 将确定 VCAM1 信号诱导 BEC 主要激活的机制。过表达野生型或突变型 VCAM1 的 BEC 将在存在或不存在 VCAM1 的情况下进行培养配体 VLA-4（极晚期抗原 4）以确定其对 BEC 突变体中炎症基因表达的影响。将使用 AAV2-BR1 病毒将 VCAM1 引入体内，显示 BEC 激活的最大程度降低评估小胶质细胞反应性和神经干细胞活性，目标 3 将确定 VCAM1 在小鼠中的作用。将系统引入 VCAM1 中和抗体模型以确定其对淀粉样蛋白的作用。通过转录组分析测量斑块、反应性小胶质细胞、认知缺陷和 BEC 激活该项目将鉴定 BEC 中 VCAM1 改变的衰老诱导的炎症通路。及其信号传导机制，并确定 VCAM1 作为 AD 治疗靶点的潜力。