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

描述(申请人提供)：这些研究将集中在哮喘(和鼻窦炎)的细胞和免疫机制，因为它们与阿司匹林加重的呼吸系统疾病(AERD)有关。我们的假设是，AERD与阿司匹林耐受哮喘的对比是，通过特定受体过度产生白三烯E4(LTE4)，并与白细胞介素4(IL)-4和干扰素(干扰素)-3发生促炎相互作用。我们还假设阿司匹林直接诱导AERD的细胞激活。AERD是一种综合征，包括严重的持续性哮喘，侵袭性的呼吸道重塑，广泛的增生性嗜酸性鼻窦炎并伴有鼻息肉(NP)形成，嗅觉障碍，以及对阿司匹林的不耐受，其特征是从鼻塞，鼻漏，喘息到危及生命的哮喘发作。阿司匹林不耐受部分反映了白三烯C4合成酶(LTC4S)和半胱氨酰白三烯(CysLT)受体表达增加，结果是，这些患者出现结构性生产过剩，对CysLTs(尤其是LTE4)的反应性增强，摄取阿司匹林后CysLT产生爆炸性增加。我们推测识别LTE4的新型受体(S)与急性呼吸窘迫综合征的病理生理学有关。我们目前的研究利用了从AERD捐赠者那里获得的永生化肥大细胞系(LUVA细胞)。这些细胞保留了肥大细胞的相关特征，包括含有组胺的分泌颗粒和Fc5RI1的表面表达。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种新的模型，通过释放颗粒内容物、钙离子通量、花生四烯酸产物和从头合成的趋化因子来响应肥大细胞。这些细胞产生一种分泌蛋白，而不是任何其他目前表征的嗜酸性粒细胞激活因子，其作用是促进嗜酸性粒细胞的造血、存活和LTC4S的表达。我们将研究LUVA条件培养液(LCM)与嗜酸性粒细胞的相互作用，以进一步确定AERD病理生理学的核心机制。提出了三个特定的目标：特定的目标1将表征LTE4通过LTE4特异性受体在AERD中的作用。具体目标2将阐述IL-4和干扰素-3在AERD中的重要性。尽管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症相关的细胞因子(如IL-5)在AERD中仅适度和可变地表达，相反，AERD表现出混合的Th1(干扰素-3)/Th2(IL-4)细胞因子“签名”。我们将集中讨论干扰素-3在促进嗜酸性粒细胞增多症中相对未知的作用，以及对AERD至关重要的LTC4S表达增强和CysLT分泌。我们将研究干扰素-3使嗜酸性粒细胞对LTE4产生反应的能力。最后，特殊目标3将描述LUVA细胞及其对阿司匹林的反应的激活。此外，我们还将确定LUVA细胞分泌的促进嗜酸性粒细胞造血和上调LTC4S的因子。 公共卫生相关性：阿司匹林加重的呼吸系统疾病(AERD)占成人哮喘患者的5%-20%，在严重哮喘患者中比例过高。AERD的许多特征尚不清楚，包括白三烯的产生和反应的病理性上调的基础，以及摄入阿司匹林后发生的细胞激活的机制。我们认为，这些白三烯通过AERD特有的受体发挥作用，它们与先前未探索的肥大细胞衍生蛋白和干扰素-3相互作用，这些特征可能被证明是治疗调节的靶点。

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.