Neurovascular Adhesion Receptors and Barrier Integrity

神经血管粘附受体和屏障完整性

• 批准号: 8395634
• 负责人: Gregory J Del Zoppo
• 金额: $ 33.8万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-16 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8395634
• 关键词: Acute; Address; Adhesions; Amyloid; Astrocytes; Basal lamina; Binding; Blood; Blood - brain barrier anatomy; Blood Vessels; Brain; Brain Edema; Brain Injuries; Cell Line; Cell-Matrix Junction; Cells; Cerebral Ischemia; Cerebrovascular Disorders; Cerebrum; Chronic; Clinical; Complex; Data; Development; Disease; Dystroglycan; Edema; Endothelial Cells; Endothelium; Extravasation; Failure; Family member; Funding; Glucose; Goals; Hemorrhage; In Vitro; Infiltration; Injury; Integrin Binding; Integrins; Interruption; Ischemia; Ischemic Stroke; Lead; Liquid substance; Mediating; Modeling; Mus; Oxygen; Pathway interactions; Peptides; Permeability; Phenotype; Process; Proteins; Research; Risk; Signal Pathway; Signal Transduction; Stroke; Testing; Tight Junctions; Validation; Vascular Diseases; Work; adhesion receptor; base; clinically relevant; cohesion; deprivation; in vivo; inhibitor/antagonist; neurovascular unit; nonhuman primate; novel; prevent; protein expression; receptor; research study; response; scaffold; treatment strategy

DESCRIPTION (provided by applicant): Ischemic stroke produces rapid profound loss of microvascular integrity. Early following focal ischemia detectable disruption in the permeability barrier of cerebral microvessels occurs, with rapid loss of the endothelial cell ¿1 integrin-matrix receptors. In amyloid angiopathy, microvessel alterations increase the risk of microhemorrhages. The hypotheses to be tested by this competing renewal Proposal state that i) the interaction of matrix receptors on microvessel endothelial cells (and astrocytes) with matri components of the basal lamina are a major determinant of the blood-brain barrier phenotype, ii) focal cerebral ischemia disrupts receptor-matrix interactions, and iii) interruptions of receptor-matrix interactions result in loss of the blood brain barrier phenotype. We have shown that adhesion of endothelial cells to the intact basal lamina matrix is central to the integrity of the barrier. The barrier phenotype (e.g. tight junctions (TJs)) and vascular matrix are generated by endothelial cells and astrocytes in concert, and are maintained by both cell compartments. The expression of ¿1 integrins on endothelial cells and ¿¿-dystroglycan on astrocytes in vivo, and their responses to focal ischemia, are mimicked by primary endothelial cells and astrocytes of murine origin in culture. These responses are matrix-dependent. Based upon successful completed work and preliminary data, we propose that ¿1 integrins can determine TJ protein expression, and constitute the "vertical" component of the blood- brain and matrix barriers. The goal of this Project is to demonstrate that the actions of specific ¿1 integrin family members are required for the integrity of the microvessel barrier, and those specific integrin inhibitors, geneic constructs and knockdowns, focal ischemia, and A¿1 peptides disrupt the receptor-matrix interactions, producing barrier failure. The Specific Aims are to demonstrate that: 1) the interactions of ¿1 integrins on confluent endothelium with matrix proteins determine inter-endothelial cell cohesion by the TJ proteins, and these are modulated by astrocytes, 2) mechanisms of ¿1 integrin signaling within endothelial cells mediate the matrix adhesion receptor-mediated changes in TJ expression (without or with astrocytes), 3) experimental ischemia significantly alters endothelial cell TJ expression by altering the endothelial cell ¿1 integrin-matrix interactions, and 4) the exposure of endothelial cells (without or with astrocytes) to A¿-peptides modulates TJ expression and the microvessel permeability barrier phenotype via ¿1 integrin-dependent mechanisms. These novel studies provide a plausible explanation for the disruption of microvessel integrity immediately following focal ischemia and by amyloid angiopathy. The "vertical" component mediated by endothelial ¿1 integrin-matrix adhesion suggests the premise that its disruption is responsible for loss of the blood-brain barrier. Understanding the mechanisms of the ¿1 integrin-matrix adhesion is likely to lead to new testable approaches to preserve or selectively alter microvessel barrier function in other neurovascular disorders. PUBLIC HEALTH RELEVANCE: Ischemic stroke is a devastating disorder that disrupts important bonds between the cells lining the small blood vessels of the brain (microvessel endothelial cells), that are thought to prevent leakage of fluid from inside the vessels, causing blood leakage and brain swelling. We have recently found that molecules (¿1 integrins) that bind the endothelial cells to the scaffolding they sit on (matrix) within each microvessel are essential for maintaining the normal barrier to leakage, and that ischemic stroke quickly disrupts ¿1 integrins, thereby causing leakage to occur. This continuing research work will define the exact mechanisms by which endothelial cell ¿1 integrin-matrix binding maintains the barrier, and how its loss contributes to brain injury during ischemic stroke and other brain vascular disorders: fundamental studies needed for the development of new treatment strategies for stroke.

描述（由申请人提供）：缺血性中风导致微血管完整性迅速严重丧失。局灶性缺血早期，脑微血管通透性屏障发生可检测到的破坏，内皮细胞 ¿1 整合素基质迅速丧失 受体。在淀粉样血管病中，微血管改变会增加微出血的风险。通过这种竞争性更新来检验的假设 提案指出，i）微血管内皮细胞（和星形胶质细胞）上的基质受体与基底层基质成分的相互作用是血脑屏障表型的主要决定因素，ii）局灶性脑缺血破坏了受体 - 基质相互作用，以及 iii） 受体-基质相互作用导致血脑屏障表型丧失。我们已经证明，内皮细胞与完整基底层基质的粘附对于屏障的完整性至关重要。屏障表型（例如紧密连接（TJ））和血管基质由内皮细胞和星形胶质细胞共同产生，并由两个细胞室维持。培养的原代内皮细胞和鼠源性星形胶质细胞可模拟体内内皮细胞上的 ¿1 整合素和星形胶质细胞上的 Ф-肌营养不良聚糖的表达及其对局灶性缺血的反应。这些响应是矩阵相关的。基于成功完成的工作和初步数据，我们提出¿1整合素可以决定TJ蛋白的表达，并构成血脑和基质屏障的“垂直”成分。该项目的目标是证明特定的 1 整合素家族成员的作用是微血管屏障完整性所必需的，而这些特定的整合素抑制剂、基因构建和敲低、局灶性缺血和 A1 肽会破坏受体-基质相互作用，导致屏障失效。具体目标是证明：1) 融合内皮上的 1 整合素与基质蛋白的相互作用决定了 TJ 蛋白的内皮细胞间凝聚力，并且这些由星形胶质细胞调节，2) 内皮细胞内 1 整合素信号传导机制介导基质粘附受体介导的 TJ 表达变化（有或没有星形胶质细胞），3) 实验性缺血通过改变内皮细胞 ¿1 整合素-基质相互作用显着改变内皮细胞 TJ 表达，4) 内皮细胞的暴露（无或有星形胶质细胞） A¿-肽通过 ¿1 整合素依赖性机制调节 TJ 表达和微血管通透性屏障表型。这些新颖的研究为局灶性缺血和淀粉样血管病立即破坏微血管完整性提供了合理的解释。由内皮β1整合素-基质粘附介导的“垂直”成分表明其破坏是导致血脑屏障丧失的前提。了解 ¿1 整合素基质粘附的机制可能会带来新的可测试方法，以保留或选择性改变其他神经血管疾病中的微血管屏障功能。 公众健康相关性：缺血性中风是一种破坏性疾病，会破坏大脑小血管内壁细胞（微血管内皮细胞）之间的重要联系，而这些细胞被认为可以防止血管内液体渗漏，从而导致血液渗漏和脑肿胀。我们最近发现，将内皮细胞与其位于每个微血管内的支架（基质）结合的分子（¿1 整合素）是必不可少的 维持正常的渗漏屏障，并且缺血性中风会迅速破坏 ¿1 整合素，从而导致渗漏发生。这项持续的研究工作将确定内皮细胞 ¿1 整合素-基质结合维持屏障的确切机制，以及它的缺失如何导致缺血性中风和其他脑血管疾病期间的脑损伤：开发新的中风治疗策略所需的基础研究。