Endoplasmic Reticulum Stress Signaling in Allergen-induced Airway Remodeling

项目摘要 严重过敏性哮喘的特征是气道炎症、重塑和高反应性， 与肺功能下降和死亡率增加相关。我们已经确定了内质网 (ER)基于未折叠蛋白反应（UPR）作为肺上皮炎症和纤维化的关键介质 对过敏原的反应。最近的报告强调，普遍定期审议途径的增加可能被归类为 一种严重哮喘的内型然而，启动普遍定期审议反应的机制， 在严重哮喘的环境中持续存在的哮喘仍然没有得到解决，并且将是本申请的焦点。 我们的新的初步结果现在表明，过敏原的挑战增加活性氧（ROS）， GRP 78中半胱氨酸ER和氧化修饰。GRP 78的氧化导致GRP 78的解离 并导致UPR传感器ATF 6 β的初始激活。我们观察到ATF 6的靶点PDIA 5， 在哮喘患者和小鼠哮喘模型中也显著上调， 肺部的过敏反应有趣的是，PDIA 5将半胱氨酸二硫化物还原为（-S-S-）， ATF 6基因，这是一个前馈调节机制，以维持普遍定期审议。基于这些 根据观察，我们假设过敏原诱导的GRP 78氧化启动了UPR信号传导， PDIA 5的随后增加延长了UPR，从而增加了过敏性气道反应。审查 根据这一假设，我们提出以下具体目标： 在具体目标#1中，我们将确定过敏原诱导的活性氧的功能作用， 随后在UPR启动中GRP 78的氧化，细胞因子/趋化因子的表达，以及随后的 促炎反应的诱导和肺重塑的发展。具体目标#2旨在 剖析过敏原诱导的PDIA 5在二硫键介导的转导子加工中的关键要求， UPR ATF 6在严重过敏性气道反应中的作用在这两个目标中，我们将使用转基因小鼠模型， 以及灵敏的氧化还原和生化分析。最重要的是，我们将检查特定抑制剂的功效 ATF 6 α（Ceapin-A7）和PDIA 5（LOC 14）在减弱过敏原诱导的UPR，降低随后的pro- 炎症反应，并最终导致过敏原诱导的肺部病理学的解决。这些研究 将阐明过敏原诱导的肺上皮UPR在促炎反应，肺 重塑，并为严重过敏性气道疾病提供了新的和急需的治疗方式 除了支持性护理。

PROJECT SUMMARY Severe allergic asthma is marked by airway inflammation, remodeling, and hyperresponsiveness, which correlates with decreased lung function and increased mortality. We have identified the endoplasmic reticulum (ER) based unfolded protein response (UPR) as a critical mediator of lung epithelial inflammatory and fibrotic responses to allergens. Recent reports highlight that increases in the UPR pathways are potentially classified as an endotype of severe asthma. However, the mechanisms whereby the UPR response is initiated and perpetuated in settings of severe asthma remain unaddressed, and will be the focus of this application. Our novel preliminary results now suggest that allergen challenge increases reactive oxygen species (ROS) in the ER and oxidative modification of cysteines in GRP78. Oxidation of GRP78 resultes in dissociation of GRP78 and causes initial activation of the UPR transducer, ATF6. We observed that the ATF6 target, PDIA5, was also significantly upregulated in both asthmatics and a mouse asthma model in association with an enhanced allergic responses in lungs. Intriguingly, PDIA5 reduces cysteines disulfides to (-S-S-) to sulfhydryls (-SH) of ATF6, which is suggestive of a feed-forward regulatory mechanism to sustain the UPR. Based on these observations, we hypothesize that allergen-induced oxidation of GRP78 initiates the UPR signaling, with subsequent increases in PDIA5 prolong the UPR and thereby increasing allergic airway responses. To examine this hypothesis, we propose the following specific aims: In Specific Aim #1 we will determine the functional role of allergen-induced reactive oxygen species and subsequent oxidation of GRP78 in initiation of the UPR, expression of cytokines/chemokines, and subsequent induction of pro-inflammatory response and development of lung remodeling. The specific Aim #2 seeks to dissect the critical requirement of allergen-induced PDIA5 in disulfide mediated processing of a transducer of UPR ATF6 in severe allergic airway responses. In both aims we will use transgenic mouse models, cell culture and sensitive redox and biochemical assays. Most importantly we will examine the efficacy of specific inhibitors of ATF6α (Ceapin-A7) and PDIA5 (LOC14) in attenuating allergen-induced UPR, decreasing subsequent pro- inflammatory responses, and ultimately resulting in resolution of allergen-induced lung pathology. These studies will shed light on the importance of the allergen-induced lung epithelial UPR in pro-inflammatory responses, lung remodeling and offers insight into new and highly needed treatment modalities for severe allergic airway disease beyond supportive care.