Mechanisms of IL-33 secretion in allergic diseases

项目概要/摘要 过敏性疾病和哮喘的患病率在世界范围内不断增加。这些疾病经常发生 在同一个体中，这表明存在共同的潜在免疫致病因素。 该项目的长期目标是研究参与的基本免疫机制， 过敏性疾病的发展。越来越清楚的是，上皮细胞产生的细胞因子 屏障表面的细胞，包括胸腺基质淋巴细胞生成素、IL-25和IL-33，在 形成2型免疫和人类过敏性疾病的病理生理学。然而，主要差距仍然存在。 我们的知识仍然涉及这些蛋白质的产生和分泌的分子和细胞控制， 细胞因子本申请的目的是通过关注IL-33来解决这些差距。 IL-33通常储存在非血液细胞的细胞核中。我们最近发现， 人气道上皮细胞对真菌过敏原Alternaria alternata的敏感性引起细胞外快速释放 ATP，其触发细胞内钙浓度的持续增加和IL-33分泌到细胞内。 细胞外环境我们还发现，ATP释放和IL-33分泌都被废除时，水平的 活性氧（ROS）被ROS清除剂和Nrf 2的小分子活化剂减少， 增加内源性抗氧化酶的表达。分泌的IL-33已被处理为19 从全长31 kDa形式中分离。因此，我们假设，在暴露于空气中时， 过敏原，气道上皮细胞的氧化应激反应触发细胞外释放ATP，导致 蛋白水解加工和高活性IL-33的分泌。 拟议的研究旨在详细调查这一过程的关键步骤。在目标1中，我们 确定氧化应激如何启动和维持气道上皮细胞释放ATP，这是一个关键的 触发IL-33分泌的步骤。在目标2中，我们将研究空气中的过敏原暴露如何诱导 通过研究晚期糖基化终产物受体在气道上皮中的作用 （二）。在目标3中，我们将研究参与IL-33加工和分泌的细胞机制 通过研究上皮内源性蛋白酶的作用。我们将采用以下组合： 实验室的分子、细胞生物学、药理学和免疫学专业知识 博士奥格雷迪和基塔医生已经为该项目开发了新颖且稳健的体外和体内模型。 这些研究将提供一个更好的理解上皮细胞如何应对环境过敏原 并将确定负责IL-33分泌的关键免疫病理生理机制。最后， 这些研究将提供参与过敏原诱导的免疫应答的关键分子的重要特征。 免疫应答，允许鉴定新的治疗靶标以治疗和理想地预防 免疫介导的疾病，如哮喘、慢性鼻窦炎和过敏性疾病。

PROJECT SUMMARY/ABSTRACT The prevalence of allergic diseases and asthma is increasing worldwide. These diseases often occur together in the same individual, suggesting the presence of common underlying immunopathogenic factors. The long-term objective of this project is to investigate the fundamental immunological mechanisms involved in the development of allergic diseases. It is becoming increasingly clear that cytokines produced by epithelial cells at the barrier surface, including thymic stromal lymphopoietin, IL-25, and IL-33, play an important role in shaping type 2 immunity and in the pathophysiology of allergic diseases in humans. However, major gaps still remain in our knowledge concerning the molecular and cellular control of production and secretion of these cytokines. The objective of this application is to address these gaps by focusing on IL-33. IL-33 is generally stored in the nucleus of non-hematologic cells. We found recently that exposure of human airway epithelial cells to a fungal allergen, Alternaria alternata, evokes a rapid extracellular release of ATP, which triggers sustained increases in intracellular calcium concentration and IL-33 secretion into the extracellular milieu. We also found that both ATP release and IL-33 secretion are abolished when levels of reactive oxygen species (ROS) are reduced by ROS scavengers and small molecule activators of Nrf2, which increases the expression of endogenous antioxidant enzymes. Secreted IL-33 had been processed to a 19 kDa form from the full-length 31 kDa form. Therefore, we hypothesize that, upon exposure to airborne allergens, the oxidative stress response in airway epithelium triggers extracellular release of ATP, resulting in proteolytic processing and secretion of highly active IL-33. The proposed study is designed to investigate the key steps of this process in detail. In Aim 1, we will determine how oxidative stress initiates and sustains the release of ATP from airway epithelial cells, a critical step that triggers IL-33 secretion. In Aim 2, we will investigate how airborne allergen exposure induces oxidative stress in airway epithelium by studying roles for the receptor for advanced glycation endproducts (RAGE). In Aim 3, we will examine the cellular mechanisms involved in the processing and secretion of IL-33 by studying the roles for the epithelium's endogenous protease. We will employ a combination of complementary molecular, cell biological, pharmacological and immunological expertise in the laboratories of Dr. O'Grady and Dr. Kita. Novel and robust in vitro and in vivo models have been developed for this project. These studies will provide a better understanding of how the epithelium responds to environmental allergens and will define the key immunopathophysiologic mechanisms responsible for secretion of IL-33. Ultimately, these studies will provide an important characterization of key molecule(s) involved in allergen-induced immune responses, allowing for identification of novel therapeutic target(s) to treat and ideally to prevent immune-mediated diseases, such as asthma, chronic rhinosinusitis, and allergic disorders.