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

• 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
• 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' s Disease; Alzheimer' s disease model; Alzheimer' s disease pathology; Alzheimer' 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

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下降，增加了神经退行性变的易感性 精神错乱。Wyss-Coray实验室的研究支持脑细胞的非自主和可逆机制 衰老受全身环境的调节。衰老的血浆导致幼年小鼠的大脑老化 在海马神经发生中，小胶质细胞的反应性增加，认知功能下降。年轻的时候 血浆可以逆转衰老小鼠的这些特征。由于亲年轻和亲衰老因素的认同正在被 据透露，目前尚不清楚它们是如何通过高度不渗透的血脑屏障进入大脑的。 我们实验室最近的工作表明，衰老的血浆上调了脑内皮细胞(BEC)的表达 一种黏附蛋白VCAM1(血管细胞黏附分子1)，在正常衰老过程中也会增加。 基因消融BECs中的VCAM1或用系统抗体中和可消除 老化的血浆，逆转大脑老化的特征。这支持了VCAM1作为 与年龄有关的循环提示。然而，目前尚不清楚VCAM1是如何改变BEC以推动大脑老化的。在单个单元格中 与VCAM1阴性的BECs相比，表达VCAM1的BECs表现出更高的炎症特征 阻断VCAM1可减轻脑部炎症，提示其可能诱导BECs的炎症信号。 除了衰老，VCAM1在阿尔茨海默病(AD)小鼠的脑血管中增加并共存 有淀粉样斑块和反应性小胶质细胞。AD患者血浆中可溶性VCAM1也显著增加 与痴呆症的严重程度和AD的病理特征相关。根据这些综合观察，这 该提案将检验这一假设，即VCAM1增加在衰老和死亡过程中扰乱脑内皮细胞信号 促进小鼠的阿尔茨海默病。目的1将确定VCAM1是否诱导炎性细胞的表达 用海马BECs单细胞转录分析和蛋白质组学分析老年BEC中的基因 微血管。实验将使用衰老的小鼠进行，其中VCAM1是从BEC基因中去除的 或用抗体中和，并使用VCAM1在BEC中使用AAV2过表达的幼鼠。 BR1病毒。目标2将确定VCAM1信号诱导BEC激活的机制。主要 过度表达野生型或突变型VCAM1的BEC将在有或无VCAM1的情况下培养 配体VLA-4(非常晚期抗原-4)，以确定其对BEC炎症基因表达的影响。突变型 使用AAV2-BR1病毒将在体内引入显示BEC活性最高降低的VCAM1 评估小胶质细胞的反应性和神经干细胞的活性。目标3将确定VCAM1在小鼠中的作用 AD的模型。将系统地引入VCAM1中和抗体以确定其对淀粉样蛋白的影响 通过转录分析检测斑块、反应性小胶质细胞、认知缺陷和BECs的激活 致炎基因。该项目将确定BECs中VCAM1改变的衰老诱导的炎症通路 以及其信号转导机制，并确定VCAM1作为AD治疗靶点的潜力。