Oxidative stress in asthma initiation

描述（由申请人提供）：哮喘是这个国家的主要健康问题。哮喘患者肺内过敏原激发可诱发“晚期哮喘表型”，包括气道高反应性（AHR）、气道粘液生成和Th2嗜酸性粒细胞炎症。大量文献揭示了花粉源性抗原蛋白的多肽和表位如何与适应性免疫系统的关键成分（即抗原呈递细胞上的II类MHC和Th2细胞上的t细胞受体）相互作用，从而诱导晚期哮喘表型。然而，从来没有证据表明花粉含有第二组具有独特生化特性的蛋白质，这些蛋白质会大力增加晚期哮喘表型。豚草花粉已知会引起人类过敏性鼻炎和哮喘。我们发现豚草提取物（RW）和许多环境花粉提取物具有强大的促氧化活性。利用RW作为原型促氧化过敏原，我们证明了这种活性是由于一种由几种不同的促氧化蛋白（POP）组成的蛋白质复合物与RW的主要抗原成分Amb A1（抗原E）紧密相关。我们创造了一个术语“促氧化蛋白和抗原复合物（POPAC）”来描述这种POP +抗原蛋白复合物。纯化的阿拉伯A1，不像整个RW或Amb A1在POPAC中络合，不具有促氧化活性。与这种促氧化活性的差异一致的是，POPAC致敏小鼠的肺内刺激，而不是Amb A1，可能会诱发过敏性炎症。我们认为RW（以及许多其他花粉和霉菌过敏原）含有POPAC，这是一种由至少两种物理相关成分组成的蛋白质复合物，一种是众所周知的抗原成分，另一种是新型的POP。本提案的总体目标是确定POP大力增强由POPAC抗原成分诱导的晚期哮喘表型的机制。在本提案中，我们将验证以下假设：popac诱导的即时氧化爆发独立于过敏致敏和适应性免疫（特异性目的1）；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（特异性目的2）；RW的促氧化活性增强即时ROS产生和晚期症状。特应性患者的粘液生成和Th2过敏性炎症（特异性目的3）。这些研究旨在阐明由存在于许多环境花粉和霉菌过敏原中的促氧化蛋白复合物（POPAC）引发的晚期哮喘表型的新范式。未来对POPAC的研究可能会发现新的哮喘治疗方法。

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.