Endoplasmic Reticulum Stress Signaling in Allergen-induced Airway Remodeling

项目总结 严重过敏性哮喘的特点是呼吸道炎症、重塑和高反应性，这些 与肺功能下降和死亡率增加有关。我们已经确定了内质网 (ER)未折叠蛋白反应(UPR)是肺上皮炎性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，启动普遍定期审议回应的机制和 在严重哮喘环境中持续存在的问题仍未得到解决，这将是本申请的重点。 我们新的初步结果表明，过敏原攻击增加了体内的活性氧物种(ROS)。 GRP78中半胱氨酸的内质网和氧化修饰GRP78氧化导致GRP78解离 并导致UPR换能器ATF6的初始激活。我们观察到ATF6的靶点PDIA5是 在哮喘患者和小鼠哮喘模型中也显著上调，与增强的 肺部过敏反应。耐人寻味的是，PDIA5将半胱氨酸二硫化物还原为(-S-S-)为巯基(-SH ATF6，这暗示了一种前馈监管机制来维持普遍定期审议。基于这些 观察到，我们假设过敏原诱导的GRP78氧化启动了UPR信号，与 随后PDIA5的增加延长了UPR，从而增加了过敏性呼吸道反应。检视 在这一假设下，我们提出了以下具体目标： 在具体目标#1中，我们将确定过敏原诱导的活性氧物种的功能作用和 GRP78随后氧化启动UPR，细胞因子/趋化因子表达，以及随后 诱导促炎反应和肺重塑的发展。第二个具体目标旨在 分析变应原诱导的PDIA5在二硫键介导的转导处理中的关键要求 UPR ATF6在严重过敏性呼吸道反应中的应用在这两个目标中，我们将使用转基因小鼠模型、细胞培养 以及敏感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疗效。 血管内皮生长因子6α(Ceapin-A7)和PDIA5(LOC14)在减轻变应原诱导的UPR中的作用 炎症反应，最终导致过敏原引起的肺部病变的消退。这些研究 将阐明变应原诱导的肺上皮UPR在促炎反应中的重要性 重塑并提供对严重过敏性呼吸道疾病的新的和迫切需要的治疗方式的洞察 而不仅仅是支持性的照顾。

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.