Transcellular Communication in Airway Inflammation and Airway Hyperresponsiveness

气道炎症和气道高反应性中的跨细胞通讯

• 批准号: 7255912
• 负责人: ALAN Richard LEFF
• 金额: $ 38.38万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7255912
• 关键词: Transcellular; Communication; Airway; Inflammation; Hyperresponsiveness

DESCRIPTION (provided by applicant): Studies are proposed to examine the mechanisms by which epithelial cells (EPI), macrophages (MO) and airway smooth muscle cells (ASMC) are activated to communicate signals for granulocyte a) adhesion /migration, b) generation of LTC4, and c) conversion of normally reactive airways into hyperresponsive airways. The central hypothesis is that the endogenous 14 kDa group V PLA2 (gVPLA2) secreted from stimulated EPI, MO or ASMC serves as an intercellular messenger protein that is highly expressed in asthmatic human airways and is inducible during immune sensitization in mouse EPI, MO and ASMC. It is hypothesized that gVPLA2 hydrolyzes the phosphatidylcholine-rich outer plasma membrane of eosinophils to cause subsequent LTC4 secretion by a novel mechanism that is independent of cPLA2 activation. In Aim 1, studies are proposed to examine the hypothesis that [32-integrin-mediated eosinophil adhesion is regulated by gVPLA2 by a novel mechanism independent of MAPK-mediated cPLA2 phosphorylation. Studies are proposed to demonstrate that gVPLA2 secreted from airway resident cells transmits the signal for induction of (32-integrin adhesion in eosinophils. Further studies are proposed to elucidate the potential pathway by which adhesion is induced under physiological conditions by gVPLA2. In Aim 2, studies are proposed to examine the cellular entry and intracellular action of endogenous gVPLA2 in mediating augmented secretion of LTC4 during transcellular communication. Further studies are proposed to test the specificity of gVPLA2 by using a neutralizing mAb against gVPLA2 or TAT-dn-cPLA2. In Aim 3, studies are proposed to examine the mechanisms of gVPLA2 and cPLA2 in the mediation of airway inflammation and airway hyperresponsiveness (AHR) in acute and chronic murine models of asthma. Based upon preliminary data, studies are proposed to test the hypothesis that endogenous secretion of gVPLA2 mediates AHR in immune sensitized mice. The effect of MCL-3G1, a mAb against gVPLA2, in blocking AHR to methacholine or gVPLA2 challenge in pre/post OA-challenge mice will be assessed. Further studies using immune-sensitized gVPLA2-knockout and cPLA2-knockout mice will be generated to establish the specific role of these enzymes in AHR and inflammatory cell migration in vivo. Data derived from these studies should elucidate a new endogenous mechanism of transcellular communication that initiates airway inflammation and AHR.

描述（由申请人提供）：建议进行研究以检查上皮细胞（EPI）、巨噬细胞（MO）和气道平滑肌细胞（ASMC）被激活以传达粒细胞信号的机制：a）粘附/迁移，b）生成LTC4，以及 c) 将正常反应性气道转化为高反应性气道。核心假设是，受刺激的 EPI、MO 或 ASMC 分泌的内源性 14 kDa V PLA2 (gVPLA2) 作为细胞间信使蛋白，在哮喘人类气道中高表达，并且在小鼠 EPI、MO 和 ASMC 的免疫敏化过程中可诱导。据推测，gVPLA2 水解嗜酸性粒细胞富含磷脂酰胆碱的外质膜，通过一种独立于 cPLA2 激活的新机制引起随后的 LTC4 分泌。在目标 1 中，提出研究来检验以下假设：[32-整合素介导的嗜酸性粒细胞粘附是由 gVPLA2 通过一种独立于 MAPK 介导的 cPLA2 磷酸化的新机制调节的。研究表明，气道驻留细胞分泌的 gVPLA2 传递诱导嗜酸性粒细胞 (32-整合素) 粘附的信号。进一步研究旨在阐明 gVPLA2 在生理条件下诱导粘附的潜在途径。在目标 2 中，建议进行研究以检查内源性 gVPLA2 在介导跨细胞通讯过程中 LTC4 分泌增加的细胞进入和细胞内作用。通过使用针对 gVPLA2 或 TAT-dn-cPLA2 的中和单克隆抗体来研究 gVPLA2 的特异性 在目标 3 中，建议研究 gVPLA2 和 cPLA2 在急性和慢性小鼠模型中介导气道炎症和气道高反应性 (AHR) 的机制。根据初步数据，建议进行研究以检验 gVPLA2 内源性分泌介导免疫致敏小鼠的 AHR 的假设。将评估 MCL-3G1（一种抗 gVPLA2 的单克隆抗体）在 OA 攻击小鼠中阻断 AHR 对乙酰甲胆碱或 gVPLA2 攻击的效果。将使用免疫致敏的 gVPLA2 敲除小鼠和 cPLA2 敲除小鼠进行进一步研究，以确定这些酶在 AHR 和体内炎症细胞迁移中的具体作用。来自这些研究的数据应该阐明启动气道炎症和 AHR 的跨细胞通讯的新内源机制。