Oxidative stress in asthma initiation

描述(申请人提供)：哮喘是这个国家的一个主要健康问题。哮喘的肺内变应原激发可导致“晚期哮喘表型”，包括气道高反应性(AHR)、气道粘液产生和Th2嗜酸性炎症。大量文献分析了花粉来源抗原蛋白的多肽和表位如何与获得性免疫系统的关键组成部分，即抗原提呈细胞上的II类MHC和Th2细胞上的T细胞受体相互作用，从而诱导晚期哮喘的表型。然而，从来没有证明花粉含有第二组蛋白质(S)，它具有独特的生化特性，可以有力地增强晚期哮喘的表型。豚草花粉已知会引起人类的过敏性鼻炎和哮喘。我们发现豚草提取物(RW)和许多环境花粉提取物都含有很强的抗氧化剂活性。以RW为原型，我们证明了这种活性是由于RW的主要抗原成分Amb A1(抗原E)与几个不同的Pro-Oxidant蛋白(POP)紧密结合而形成的蛋白质复合体。我们创造了一个术语“前氧化蛋白和抗原复合体(POPAC)”来描述这种POP抗原蛋白复合体。与整个RW或与POPAC络合的AmB A1不同，纯化的阿拉伯A1不具有促氧化活性。与促氧化活性的这种差异一致，用POPAC而不是Amb A1对致敏小鼠进行肺内攻击，有效地诱导了过敏性炎症。我们认为RW(以及许多其他花粉和霉菌变应原)含有POPAC，一种至少由两个物理相关成分组成的蛋白质复合体，众所周知的抗原成分，以及一种新的POP。这项建议的首要目标是确定POP大力增强POPAC抗原成分诱导的晚期哮喘表型的机制。在这项建议中，我们将测试假设，即POPAC诱导的即时氧化爆发不依赖于过敏增敏和适应性免疫(特异性目标1)，以及促氧化蛋白增强过敏致敏和抗原诱导的小鼠晚期AHR、粘蛋白产生和Th2过敏性炎症(特异性目标2)，RW的促氧化活性增加即刻ROS产生和特应性患者的晚期症状，粘液产生和Th2过敏性炎症(特异性目标3)。这些研究旨在阐明一种新的晚期哮喘表型，这种表型是由许多环境中的花粉和霉菌变应原中存在的促氧化蛋白复合体(POPAC)启动的。未来对POPAC的研究可能会发现治疗哮喘的新方法。

DESCRIPTION (provided by applicant): Asthma is a major health problem in this country. Intrapulmonary allergen challenge in asthma induces a "late phase asthma phenotype," consisting of airway hyperresponsiveness (AHR), airway mucus production, and Th2 eosinophilic inflammation. A large body of literature has dissected out how peptides and epitopes of pollen-derived antigenic proteins interact with critical components of the adaptive immune system namely Class II MHC on antigen presenting cells, and T-cell receptor on Th2 cells, to induce late phase asthma phenotype. However, it has never been shown that pollens contain a second set of protein(s) with unique biochemical properties that vigorously augments late phase asthma phenotype. Ragweed pollens are known to induce allergic rhinitis and asthma in humans. We discovered that ragweed extract (RW) and many environmental pollen extracts contain potent pro-oxidant activity. Using RW as a prototypic pro-oxidant allergen, we demonstrated that this activity was due to a protein complex consisting of several distinct Pro-Oxidant Proteins (POP) tightly associated with Amb A1 (antigen E), the major antigenic component of RW. We coined a term" Pro-Oxidant Protein and Antigen Complex, (POPAC)" to describe this POP + antigen protein complex. Purified Arab A1, unlike whole RW or Amb A1 complexed in POPAC, did not possess pro-oxidant activity. Consistent with this difference in pro-oxidant activity, intrapulmonary challenge of sensitized mice with POPAC, but not Amb A1, potently induced allergic inflammation. We propose that RW (and many other pollen and mold allergens) contains POPAC, a protein complex of at least two physically associated components, the well-known antigenic component, and a novel POP. The overarching goal of this proposal is to determine the mechanism by which POP vigorously augments the late phase asthma phenotype induced by the antigenic component of POPAC. In this proposal, we will test the hypotheses that POPAC-induced immediate oxidative burst is independent of allergic sensitization and adaptive immunity (specific aim 1), and that pro-oxidant proteins augment allergic sensitization and antigen-induced late phase AHR, mucin production and Th2 allergic inflammation in mice (specific aim 2), pro-oxidant activity of RW augments immediate ROS production and late phase symptoms, mucus production and Th2 allergic inflammation in atopic patients (specific aim 3). These studies are designed to elucidate a novel paradigm of late phase asthma phenotype that is initiated by pro-oxidant protein complex (POPAC) present in many environmental pollen and mold allergens. Future studies of POPAC may identify novel therapeutic approaches in asthma.