Interplay between LTE4/LTE4 receptors and IFN-y with mast cells and eosinophils i

描述（由申请人提供）：这些研究将集中于哮喘（和鼻窦炎）的细胞和免疫机制，因为它们与阿司匹林加重呼吸系统疾病（AERD）有关。我们的假设是，与阿司匹林耐受性哮喘相比，AERD通过过量产生白三烯E4 (LTE4)，通过特定受体作用，并与白细胞介素(IL)-4和干扰素(IFN)-3相互作用。我们还假设阿司匹林直接诱导AERD的细胞活化。AERD是一种由严重持续性哮喘、侵袭性气道重塑、广泛增生性嗜酸性鼻窦炎伴鼻息肉（NP）形成、嗅觉缺失和阿司匹林不耐受组成的综合征，其症状包括鼻塞、鼻溢、喘息和危及生命的哮喘发作。阿司匹林不耐受在一定程度上反映了白三烯C4合成酶（LTC4S）和半胱氨酸白三烯（CysLT）受体表达的增加，因此，这些患者在摄入阿司匹林后产生CysLT（特别是LTE4）的爆炸性增加，从而产生构成性过量和对CysLT（特别是LTE4）的反应性增强。我们假设识别LTE4的新受体与AERD的病理生理有关。我们目前的研究利用了从AERD供体中获得的永生化肥大细胞系（“LUVA”细胞）。这些细胞保留肥大细胞的相关特征，包括具有含有组胺的分泌颗粒和表面表达Fc5RI1。LUVA细胞为研究阿司匹林直接激活肥大细胞的分子基础提供了一个新的模型，它们通过释放颗粒含量、Ca+2通量、花生四烯酸产物和从头合成的趋化因子来响应。这些细胞产生一种分泌蛋白，这种蛋白不是目前已知的任何一种嗜酸性粒细胞活化因子，可促进嗜酸性粒细胞造血、存活和LTC4S表达。我们将研究LUVA条件培养基（LCM）与嗜酸性粒细胞的相互作用，以进一步确定AERD病理生理的核心机制。特异性目的1将表征LTE4通过LTE4特异性受体在AERD中的作用。特异性目标2将讨论IL-4和IFN-3在AERD中的重要性。尽管AERD具有严重的嗜酸性粒细胞增多的特征，但与嗜酸性粒细胞增多相关的细胞因子（如IL-5）在AERD中仅适度和可变地表达，而表现出混合的Th1 (IFN-3)/Th2 （IL-4）细胞因子“特征”。我们将重点关注IFN-3在促进嗜酸性粒细胞增多、增强LTC4S表达和CysLT分泌方面相对未被探索的作用，这是AERD的核心。我们将研究IFN-3使嗜酸性粒细胞对LTE4反应的能力。最后，特异性靶3将描述LUVA细胞及其对阿司匹林反应的激活。此外，我们将定义LUVA细胞分泌的增强嗜酸性粒细胞造血和上调LTC4S的因子。

DESCRIPTION (provided by applicant): These studies will focus on cellular and immune mechanisms of asthma (and sinusitis) as they pertain to aspirin-exacerbated respiratory disease (AERD). Our hypothesis is that AERD contrasts with aspirin tolerant asthma through excessive production of leukotriene E4 (LTE4) acting through specific receptors and a pro- inflammatory interplay with both interleukin (IL)-4 and interferon (IFN)-3. We also hypothesize that aspirin directly induces cellular activation in AERD. AERD is a syndrome consisting of severe persistent asthma, aggressive airway remodeling, extensive hyperplastic eosinophilic sinusitis with nasal polyp (NP) formation, anosmia, and an intolerance to aspirin characterized by symptoms ranging from nasal congestion, rhinorrhea, and wheezing to life-threatening asthma attacks. Aspirin intolerance reflects, in part, increased expression of leukotriene C4 synthase (LTC4S) and cysteinyl leukotriene (CysLT) receptor expression and, as a result, these patients have constitutive overproduction and heightened responsiveness to CysLTs (especially LTE4) with an explosive increase in CysLT production following ingestion of aspirin. We hypothesize that novel receptor(s) recognizing LTE4 are relevant to the pathophysiology of AERD. Our current studies take advantage of having generated an immortalized mast cell line ("LUVA" cells) derived from an AERD donor. These cells preserve relevant features of mast cells including possessing secretory granules containing histamine and surface expression of Fc5RI1. LUVA cells provide a novel model for investigating the previously unexplored molecular basis for direct mast cell activation by aspirin, to which they respond with release of granule contents, Ca+2 fluxes, arachidonate products, and de novo synthesized chemokines. These cells produce a secreted protein that is not any other currently characterized eosinophil-activating factor that acts to promote eosinophil hematopoiesis, survival, and LTC4S expression. We will investigate the interaction of LUVA conditioned medium (LCM) with eosinophils to further define mechanisms central to the pathophysiology of AERD. Three specific aims are proposed: Specific Aim 1 will characterize influences of LTE4 acting through LTE4-specific receptors in AERD. Specific Aim 2 will address the importance of IL-4 and IFN-3 in AERD. Although characterized by profound eosinophilia, cytokines typically associated with eosinophilia (e.g., IL-5) are only modestly and variably expressed in AERD, which instead displays a mixed Th1 (IFN-3)/Th2 (IL-4) cytokine "signature". We will focus on the relatively unexplored role of IFN-3 in promoting eosinophilia and the enhanced LTC4S expression and CysLT secretion that are central to AERD. We will investigate the ability of IFN-3 to render eosinophils responsive to LTE4. And finally, specific aim 3 will characterize LUVA cells and their activation in response to aspirin. In addition, we will define the factor secreted by LUVA cells that enhances eosinophil hematopoiesis and upregulation of LTC4S. PUBLIC HEALTH RELEVANCE: Aspirin-exacerbated respiratory disease (AERD) comprises 5-20% of adult asthmatics and is over-represented among severe asthmatics. Many features of AERD are poorly understood, including the basis for the pathognomonic upregulation of leukotriene production and responsiveness and the mechanism for the cellular activation that occurs after aspirin ingestion. We propose that these leukotrienes act through receptors unique to AERD and they interact with a previously unexplored mast cell-derived protein and IFN-3, features that may prove to be targets for therapeutic modulation.