Eosinophil Activities in Murine Models of Lung Disease

描述（由申请人提供）：最近对哮喘患者的研究清楚地表明，根据临床环境中显示的症状和炎症特征，哮喘患者群体是多样化的。因此，除了通常通过皮质类固醇控制的嗜酸性气道炎症的过敏性患者外，研究还发现越来越多的患者更难治疗，包括类固醇难治性 重度患者同时显示嗜酸性粒细胞和嗜酸性粒细胞炎性疾病变体。这种免疫应答的更大多样性部分由肺应答的变应原特异性T细胞可塑性介导。值得注意的是，我们在小鼠中进行的同步研究表明，嗜酸性粒细胞在免疫调节所必需的途径中的作用以及肺部发生的炎症事件的特征未得到充分认识。这项工作起源于我们使用嗜酸性粒细胞缺陷小鼠（PHIL）的早期研究，然而，我们最近使用新创建的诱导型嗜酸性粒细胞缺陷小鼠（iPHIL）的研究使我们认为，过敏原激发时的嗜酸性粒细胞活性与T细胞亚型的多样性有关， 肺部炎症（即，嗜酸性、嗜酸性或混合变体）。拟议的研究利用这些初步数据以及我们创建的“下一代”小鼠模型（eoCRE），允许嗜酸性粒细胞特异性基因敲除和靶基因过表达。我们将检验嗜酸性粒细胞活性通过以下方式促成过敏性呼吸道炎症特征的中心假设：（i）对肺中中性粒细胞募集/蓄积的直接影响，以及（ii）调节过敏原特异性T细胞亚型选择，在嗜酸性粒细胞存在的情况下极化对Th 2的反应，在不存在嗜酸性粒细胞的情况下极化对Th 17/Th 1的反应。从长远来看，我们的目标是确定可能解释患者疾病表型多样性的潜在机制，以及当前治疗（如使用皮质类固醇和美泊利珠单抗）的混淆问题。本研究的目的是通过完成以下具体目标来验证我们的中心假设：（1）证明嗜酸性粒细胞通过表达来源于12/15-脂氧合酶活性的抗炎脂质直接抑制变应原诱导的气道中性粒细胞水平;（2）确定嗜酸性粒细胞来源的IL-4和TGF β的意义。表达作为调节T细胞亚型的机制，导致Th 2显性对嗜中性混合Th 2/Th 17/Th 1免疫应答;（3）确定类固醇难治性嗜酸性粒细胞亚群的过敏性呼吸道炎症是否由嗜酸性粒细胞引起，皮质类固醇介导的消融作用或作为靶向嗜酸性粒细胞和Th 2 T细胞的组合结果。

DESCRIPTION (provided by applicant): Recent studies of asthma patients clearly demonstrate a diverse population based on symptoms and the character of inflammation displayed in clinical settings. Thus, in addition to allergic patients with eosinophilic airway inflammation that are generally controlled through corticosteroids, studies have identified growing populations of patients that are much more difficult to treat, including steroid refractory severe patients displaying both eosinophilic and neutrophilic inflammatory disease variants. This greater diversity of immune responses is mediated, in part, by allergen-specific T cell plasticity of pulmonary responses. Significantly, our concurrent studies in the mouse have suggested that eosinophils have under- appreciated roles in pathways necessary for immune regulation and the character of the inflammatory events occurring in the lung. This work originated with our early studies using eosinophil-deficient mice (PHIL), however, our more recent studies using a newly created inducible eosinophil-deficient mouse (iPHIL) have led us to suggest that eosinophil activities at the time of allergen challenge are linked to the diversity of T cell subtypes driving pulmonary inflammation (i.e., eosinophilic, neutrophilic, or mixed variants). The proposed studies capitalize on these preliminary data as well as our creation of a "next generation" mouse model (eoCRE) allowing eosinophil-specific gene knockouts and targeted gene overexpression. We will test the central hypothesis that eosinophil activities contribute to the character of alleric respiratory inflammation by (i) direct effects on neutrophil recruitment/accumulation in the lung and by (ii) modulating allergen-specific T cell subtype selection, polarizing responses to Th2 in the presence of eosinophils and Th17/Th1 in their absence. In the long term, our goal is to identify potential mechanisms that may explain the diversity of disease phenotypes in patients and confounding issues surrounding current therapies such as the use of corticosteroids and Mepolizumab". The objectives of this proposal will test our central hypothesis by the completion of the following Specific Aims: (1) To demonstrate that eosinophils directly suppress the level of allergen-induced airway neutrophils through the expression of anti-inflammatory lipids derived from 12/15- lipoxygenase activities; (2) To define the significance of eosinophil-derived IL-4 and TGF¿ expression as mechanisms modulating T cell subtypes leading to Th2 dominant vs. neutrophilic mixed Th2/Th17/Th1 immune responses; (3) To determine if steroid refractory neutrophilic subsets of allergic respiratory inflammation arise from eosinophil-ablating effects mediated by corticosteroids or as a combined consequence of targeting eosinophil and Th2 T cells.