Dual Oxidase in Airway Epithelial Injury and Inflammation

描述（由申请人提供）：NADPH氧化酶DUOX 1在呼吸道上皮内显著表达，并通过促进介导伤口反应和各种炎症介质或粘蛋白基因产生的H2 O2依赖性信号传导途径，在先天性气道上皮对损伤或感染刺激的反应中被激活。在上一个资助周期的研究中，我们已经确定了DUOX 1激活促进表皮生长因子受体（EGFR）激活的氧化机制，作为伤口反应和炎症介质产生的关键事件，并观察到过敏性哮喘模型中DUOX 1表达增加与EGFR激活增加和粘液化生相关。呼吸道上皮通过产生上皮细胞因子如白细胞介素-33（IL-33），在协调对空气传播的过敏原的先天性和适应性免疫应答中至关重要。IL-33是过敏性炎症动物模型中的重要介质，也是哮喘的主要易感基因。IL-33通常存在于肺上皮细胞的细胞核内，并且响应于各种刺激和过敏原而快速分泌，以用作刺激靶细胞上的ST 2受体的警报蛋白，从而诱导先天性TH 2细胞显性免疫应答。参与调节IL-33分泌的细胞机制仍然知之甚少，然而，我们现在提出的初步证据表明，DUOX 1依赖性生产的H2 O2作为一个关键的调解人在上皮细胞IL-33分泌的重要性，两种常见的过敏原，互隔交链孢菌和屋尘螨（屋尘螨）。我们的研究进一步表明蛋白酶激活受体（PAR）和瞬时受体电位（TRP）通道在对这些过敏原的近端反应中的重要性，导致DUOX 1活化和IL-33分泌。此外，我们有初步证据表明H2 O2介导的EGFR活化是DUOX 1活化促进核输出和/或IL-33分泌的关键机制。本更新申请的主要目的是确定DUOX 1激活在介导IL-33分泌和随后各种蛋白酶过敏原引起的过敏性炎症中的共同作用（Aim 1），阐明DUOX 1激活促进IL-33核输出和分泌的下游氧化还原机制，重点关注EGFR激活的作用（Aim 2），并通过确定这些患者鼻上皮过敏原应答中DUOX 1表达和活化之间的关联来扩展我们在过敏性哮喘人类受试者研究中的发现（目的3）。这些研究的成功完成将确定DUOX 1作为一种新的和有吸引力的治疗目标，在管理哮喘和/或其加重。

DESCRIPTION (provided by applicant): The NADPH oxidase DUOX1 is prominently expressed within the respiratory epithelium and has been invoked in innate airway epithelial responses to injury or infectious stimuli, by promoting H2O2-dependent signaling pathways that mediate wound responses and production of various inflammatory mediators or mucin genes. In studies during the previous funding cycle, we have identified oxidative mechanisms by which DUOX1 activation promotes the activation of epidermal growth factor receptor (EGFR) as a critical event in wound responses and inflammatory mediator production, and observed increased DUOX1 expression in models of allergic asthma in association with increased EGFR activation and mucus metaplasia. The respiratory epithelium is critical in coordinating innate and adaptive immune responses to airborne allergens, by production of epithelial cytokines such as interleukin-33 (IL-33). IL-33 was recently identified as a critical mediator in animal models of allergic inflammation, and a major susceptibility gene for asthma. IL-33 is normally present within the nuclei of pulmonary epithelial cells, and is rapidly secreted in response to various stimuli and allergens to function as an alarmin that stimulates ST2 receptors on target cells to induce innate TH2 cell-dominant immune responses. The cellular mechanisms involved in regulating IL-33 secretion are still poorly understood, however, and we now present preliminary evidence demonstrating the importance of DUOX1-dependent production of H2O2 as a critical mediator in epithelial IL-33 secretion in response to two common allergens, Alternaria alternata and Dermatophagoides pteronyssinus (house dust mite). Our studies further indicate the importance of protease-activated receptors (PAR) and transient receptor potential (TRP) channels in proximal responses to these allergens leading to DUOX1 activation and IL-33 secretion. In addition, we have preliminary evidence demonstrating H2O2-mediated EGFR activation as a critical mechanism by which DUOX1 activation promotes nuclear export and/or secretion of IL-33. The main objectives of this renewal application are to establish the common role of DUOX1 activation in mediating IL-33 secretion and subsequent allergic inflammation by various protease allergens (Aim 1), to clarify the downstream redox mechanisms by which DUOX1 activation promotes IL-33 nuclear export and secretion, focusing on the role of EGFR activation (Aim 2), and to expand our findings in studies with human subjects with allergic asthma by determining associations between DUOX1 expression and activation in nasal epithelial allergen responses in these patients (Aim 3). Successful accomplishment of these studies would identify DUOX1 as a novel and attractive therapeutic target in the management of asthma and/or its exacerbations.