Non-Classical Cytokine Secretion in Chronic Airway Disease

摘要 慢性下呼吸道疾病是美国和世界范围内发病率和死亡率的主要原因。 目前还没有有效的疾病修饰疗法，并且仍然不清楚如何定义和优化 治疗哮喘和COPD（慢性阻塞性肺病; 慢性支气管炎和肺气肿）。这项机制研究旨在确定新的途径， 基于患病气道上皮细胞作为慢性炎症上游驱动因素的作用的治疗干预 呼吸道疾病作为该提案的基础，多项人类临床和转化研究以及 过敏原-烟雾-和病毒诱导的动物模型已经巩固了致病性上皮- 衍生的细胞因子IL-33在COPD和哮喘中的作用。然而，一个主要的知识差距仍然是理解， 核隔离的IL-33可被激活并从患病气道细胞分泌的机制 来驱动炎症。在这里，我们提出了初步的数据，表明人类COPD气道上皮细胞， 细胞表达水平增加的截短的、剪接的IL-33同种型，其能够逃逸细胞核， 大量分泌的隔离物。我们的分析进一步揭示了这种分泌的IL-33的新特征 同种型，包括翻译后修饰、与外泌体相关的伴侣蛋白的相互作用，以及 利用外泌体运输途径进行分泌。因此，本研究旨在阐明 这些新发现的IL-33生物学特征在慢性气道疾病发病机制中的作用。目标1将 定义IL-33与外泌体伴侣的相互作用如何增强细胞因子分泌和受体活化 使用人类细胞和小鼠气道疾病模型， 人类呼吸道疾病标本。目的2将研究翻译后修饰在 通过类似的方法增加IL-33分泌和受体活化以传播疾病， 使用人类细胞和小鼠模型，并在人类样本中进行验证。总之，这些目标将 解决启动和维持慢性气道疾病的病理过程中的关键步骤， 靶向粘膜界面外泌体介导的细胞因子分泌的新方法。

Abstract Chronic lower respiratory tract disease is a major cause of morbidity and mortality in the U.S. and worldwide. Currently there are no effective disease-modifying therapies and it remains unclear how to define and optimally treat disease endotypes within the spectrum of asthma and COPD (chronic obstructive pulmonary disease; chronic bronchitis and emphysema). This mechanistic research aims to define new pathways amenable to therapeutic intervention based on the role of diseased airway epithelial cells as an upstream driver of chronic airway disease. As a foundation for this proposal, multiple human clinical and translational studies as well as allergen- smoke- and virus-induced animal models have solidified the relevance of the pathogenic epithelial- derived cytokine IL-33 in COPD and asthma. However, a major knowledge gap that remains is understanding the mechanism by which nuclear-sequestered IL-33 can be activated and secreted from diseased airway cells to drive inflammation. Here we present preliminary data that demonstrates human COPD airway epithelial cells express increased levels of a truncated, spliced IL-33 isoform, which is capable of escaping nuclear sequestration to be abundantly secreted. Our analysis further revealed novel features of this secreted IL-33 isoform including post-translational modification, interaction with exosome-associated chaperones, and utilization of exosome trafficking pathways for secretion. Accordingly, this study aims to elucidate the impact of these newly-discovered features of IL-33 biology on the pathogenesis of chronic airway disease. Aim 1 will define how IL-33 interaction with exosomal chaperones enhances cytokine secretion and receptor activation to drive airway disease, using human cellular and mouse airway disease models coupled with validation in human airway disease specimens. Aim 2 will investigate the role of post-translational modification in augmenting IL-33 secretion and receptor activation to propagate disease, through an analogous approach using human cellular and mouse models with validation in human specimens. Together, these aims will address key steps in the pathologic sequence that initiates and sustains chronic airway disease, illuminating novel ways to target exosome-mediated cytokine secretion at the mucosal interface.