Mechanisms and Consequences of Eosinophil Integrin Activation

嗜酸性粒细胞整合素激活的机制和后果

• 批准号: 8044123
• 负责人: DEANE Fremont MOSHER
• 金额: $ 43.21万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8044123
• 关键词: Address; Adhesions; Adhesives; Allergic; Alpha Granule; Asthma; Blood; Blood Platelets; Blood specimen; Cell Membrane Proteins; Cells; Correlative Study; Endothelial Cells; Eosinophilia; Epitopes; Exhalation; Exposure to; Extracellular Matrix; Glycoproteins; Hand; ITGAM gene; In Vitro; Integrins; Interleukin-5; Lead; Learning; Ligands; Lung; Measurement; Measures; Mediating; Membrane; Metalloproteases; Movement; P-Selectin; Patients; Plasma; Proteolysis; Research; Role; Severities; Signal Pathway; Sputum; Structure; Surface; Testing; Time; Vascular Cell Adhesion Molecule-1; Weibel-Palade Bodies; Whole Blood; antigen challenge; asthmatic patient; cell motility; cell type; eosinophil; eosinophilic inflammation; trafficking; volunteer

This project focuses on the mechanism of activation of pi integrins on eosinophils (EOS) in the blood of patients with asthma; the role of such activation in selective movement of EOS into the airway; and'two phenomena that we hypothesize are important for movement of EOS within the airway, formation of podosomes and activation of aMp2 integrin. Aim 1 addresses the hypothesis'that interaction of blood EOS Pselectin glycoprotein ligand (PSGL) with P-selectin, which is normally sequestered in a-granules of platelets and Weibel-Palade bodies of endothelial cells, is responsible for enhanced p1 activation. This hypothesis will be tested by correlative studies of blood samples obtained from patients with asthma of varying severity and asthmatic volunteers studied after whole lung or segmental lung antigen challenge. Measurements will be made of the amounts of the N29 activation-sensitive epitope of pi on circulating EOS, P-selectin associated with circulating EOS, P-selectin on the surface of circulating platelets, and soluble P-selectin in plasma. In vitro studies will compare how the various forms of P-selectin enhance expression of the N29 epitope on EOS when added to blood and identify signaling pathways important for the increased expression. Aim 2 addresses the hypothesis that activation of a4p1, the major pi integrin on EOS, primes the EOS to arrest in vascular cell adhesion molecule (VCAM)-expressing vessels of asthmatic lung and thus enter the airway. We will correlate N29 epitope expression with various measures of eosinophilic inflammation in lung and relate the time course of changes of N29 expression after lung Ag challenge vis-a-vis changes in P-selectin. Parallel in vitro studies will test if P-selectin enhances EOS adhesion from whole blood under static and flow conditions and identify signaling pathways important for the increased adhesion. The podosome is a transient structure that mediates interaction with and proteolysis of adhesive ligands in extracellular matrix. The podosome of EOS, which forms when cells stimulated with IL-5 and/or TNF-a adhere via a4p1 to VCAM, has a distinctive set of associated cytoskeletal and cell membrane proteins when compared to podosomes of other cell types. Included within this set is the ADAMS membrane metalloproteinase. Aim 3 tests the hypotheses that podosomes and ADAMS contribute to the robust proteolytic capacity of adherent EOS; and that there is a "hand-off1 when the EOS enter the lung such that aMp2, which is activated upon exposure to IL-5, replaces a4p1, which is degraded in podosomes, as the principal adhesive integrin. The research will lead to a better understanding of trafficking of EOS in asthma and how trafficking may be modulated pharmacologically.

该项目重点研究血液中嗜酸性粒细胞（EOS）上pi整合素的激活机制 哮喘患者；这种激活在 EOS 选择性移动到气道中的作用；和两个 我们假设的现象对于 EOS 在气道内的运动、足小体的形成很重要 和 aMp2 整合素的激活。目标 1 提出了血液 EOS P 选择素相互作用的假设 糖蛋白配体 (PSGL) 与 P-选择素，通常隔离在血小板的 a 颗粒中 内皮细胞的 Weibel-Palade 小体负责增强 p1 激活。这个假设将 通过对从不同严重程度的哮喘患者获得的血液样本进行相关研究进行测试 哮喘志愿者在全肺或部分肺抗原激发后进行研究。测量结果将是 由循环 EOS 上 pi 的 N29 激活敏感表位的量组成，P-选择素相关 具有循环EOS、循环血小板表面的P-选择素以及血浆中的可溶性P-选择素。在 体外研究将比较不同形式的 P-选择素如何增强 N29 表位的表达 将 EOS 添加到血液中并确定对于表达增加很重要的信号通路。目标2 解决了这样的假设：a4p1（EOS 上的主要 pi 整合素）的激活会促使 EOS 停滞在 表达哮喘肺血管细胞粘附分子（VCAM）的血管，从而进入气道。我们 将 N29 表位表达与肺部嗜酸性粒细胞炎症的各种测量相关联，并将 肺Ag攻击后N29表达变化相对于P-选择素变化的时间过程。 平行体外研究将测试 P-选择素是否增强静态和流动状态下全血的 EOS 粘附 条件并确定对于增加粘附力很重要的信号通路。足体是一个 介导细胞外基质中粘附配体的相互作用和蛋白水解的瞬时结构。 EOS 的足体，当用 IL-5 和/或 TNF-a 刺激的细胞通过 a4p1 粘附到 与其他细胞相比，VCAM 具有一组独特的相关细胞骨架和细胞膜蛋白 其他细胞类型的足体。该套件中包括 ADAMS 膜金属蛋白酶。目标 3 测试足体和 ADAMS 有助于粘附细胞强大的蛋白水解能力的假设 EOS；并且当 EOS 进入肺部时，存在“交接1”，使得 aMp2 被激活 暴露于 IL-5，取代在足体中降解的 a4p1，作为主要的粘附整合素。这 研究将有助于更好地了解哮喘中的 EOS 贩运以及贩运可能如何进行 药理调节。