Regulation of Inflammation in Asthma by Fas Ligand

描述（由申请人提供）：气道炎症与哮喘发病机制高度相关，其特征是活化的Th2淋巴细胞、嗜酸性粒细胞和某些情况下的中性粒细胞。大多数白细胞表达Fas死亡受体的事实表明，这一途径应该是一种重要的内源性消除手段。然而，关于气道中FasL表达的数据缺乏，并且哮喘中FasL机制调节气道炎症的程度尚不清楚。我们假设在气道中产生的FasL和FasL诱饵活性（可溶性Fas异构体和DcR3）的平衡将是ige介导的炎症反应强度和持续时间的重要决定因素。促凋亡FasL活性应有助于限制哮喘中的炎症反应，并对哮喘的消退起重要作用，而FasL诱骗物应在这种情况下促进炎症，并可能在哮喘发作过程中起重要作用。这项建议包括四个相互关联的目标。首先需要明确表征气道炎症期间负责产生FasL和FasL诱饵的主要细胞类型，并证明它们可以通过可溶性配体或诱饵受体活性调节自身的活力（自分泌效应）或相关的FasL承载靶标（旁分泌效应）。第二种方法是通过常驻气道巨噬细胞中的细胞因子对这些物种进行调节，在Pl之前的K08项目中，我们发现这种细胞类型在抗原激发后强烈表达FasL蛋白。第三，表征内源性sFas异构体，并在分子水平上表征炎症峰值时产生的潜在FasL:sFas和FasL:DcR3复合物。虽然在实验系统和我们的初步数据中暗示了这种复合物的存在，但它们在体内的存在和相关性尚不清楚。本提案的主要研究材料来源将来自使用节段性抗原激发（SAC）的人气道哮喘模型，重点是支气管肺泡灌洗室。将对结构单元进行有限的分析！S在组织室。最后，为了帮助支持人类气道细胞中FasL促凋亡活性的假设，我们将在FasL中和条件下的小鼠中进行挑战研究。

DESCRIPTION (provided by applicant): Airway inflammation is highly associated with asthma pathogenesis and is characterized by activated Th2 lymphocytes, eosinophils and, in some cases neutrophils. The fact that the most leukocytes express the Fas death receptor implies that this pathway should be an important endogenous means of their elimination. However, there is a paucity of data regarding FasL expression in the airway, and the extent to which FasL mechanisms regulate airway inflammation in asthma is unknown. We hypothesize that the balance of FasL and FasL decoy activity (soluble Fas isoforms and DcR3) generated in the airway will be an important determinant of the intensity and duration of an IgE-mediated inflammatory response. Pro-apoptotic FasL activity should serve to limit the inflammatory response in asthma and be important for resolution, while FasL decoys should promote inflammation in this setting and may be important during initiation. This proposal consists of four interrelated aims. The first entails the definitive characterization of the principal cell types responsible for production of FasL and FasL decoys during airway inflammation and demonstrating that they can regulate their own viability (autocrine effect), or that of relevant Fas-bearing targets (paracrine effect), via soluble ligand or decoy receptor activity. The second entails regulation of these species by cytokines in resident airway macrophages, a cell type that we have found strongly expresses FasL protein after antigen challenge in work done as part of the Pl's previous K08 project. Third, endogenous sFas isoforms will be characterized, and potential FasL:sFas and FasL:DcR3 complexes generated during peak inflammation will be characterized on a molecular level. Whilethe existence of such complexes is implied in experimental systems and by our preliminary data, their existence and relevance in vivo is not known. The major source of research materials for this proposal will be derived from a human airway model of asthma using segmental antigen challenge (SAC), with a focus on the bronchoalveolar lavage compartment. There will be a limited analysis of structural cel!s in the tissue compartment. Finally, in order to help support the hypothesis that pro-apoptotic FasL activity characterized in human airway cells is truly physiologic, we will perform challenge studies in mice under FasL neutralizing conditions.