A novel role for the adapter molecule NHERF1 in regulating asthma and allergic re

描述(申请人提供)：过敏反应和哮喘等过敏性疾病影响了大约10%的美国人，10岁以下的儿童可能会致命。重要的是，这些疾病每年导致50万人住院，医疗费用高达数十亿美元。过去30年的密集研究增加了我们对哮喘和其他过敏性疾病的发病机制的了解。已证实免疫球蛋白E(IgE)和肥大细胞在变态反应性疾病的发病机制中起关键作用。Ig E受体(FcϵRI)通过Ig E和变应原/抗原聚集在肥大细胞上，导致炎症介质如组胺和白三烯的快速释放，这一过程被称为“脱颗粒”。肥大细胞还会释放大量的细胞因子和趋化因子，导致中性粒细胞等其他免疫细胞的涌入，从而放大过敏反应。近年来，肥大细胞上表达的G蛋白偶联受体(G蛋白偶联受体)可增强IgE诱导的免疫应答。肥大细胞表达补体成分C3a(C3aR)的GPCR，肥大细胞特异的C3aR激活增强了IgE诱导的被动皮肤过敏反应(PCA)和气道高反应性(AHR)。C3aR的羧基末端有一个I类PSD-95/DLG/Zo1(PDZ)结合基序。Na+/H+交换调节因子(NHERF1-4)是PDZ结构域蛋白I类家族中的一员，它结合多个GPC并调节它们的运输和信号转导。最近，我证明了NHERF1促进C3a激活的肥大细胞脱颗粒和趋化因子的产生。然而，NHERF1不与C3aR的贩运相互作用或影响。因此，NHERF1可能利用一条独特的、未知的途径来调节人类肥大细胞中的C3aR信号。此外，NHERF1是否在体内调节C3a介导的肥大细胞反应，还有待评估。这项建议建立在我最近的观察基础上，旨在确定NHERF1在体外调节人肥大细胞脱颗粒到C3a的信号通路(目标1；指导阶段)。在独立阶段，我将研究NHERF1在调节肥大细胞介导的体内反应中的作用，如在哮喘小鼠模型中的PCA(AIM 2)和AHR以及肺部炎症(AIM 3)。这些研究的完成将有助于确定NHERF1在肥大细胞中的直接轴和体内的过敏反应，并将为NHERF1拮抗剂的未来发展提供见解，这些拮抗剂不仅可以针对过敏反应和哮喘，还可以针对其他肥大细胞介导的过敏性疾病。我的导师团队将由海达尔·阿里博士(首席导师)、约翰·D·兰布里斯博士(共同导师)和布鲁斯·弗里德曼博士、雷诺德·A·帕内蒂耶里博士和Taku Kambayashi博士(科学咨询委员会)组成，他们都是宾夕法尼亚大学(宾夕法尼亚大学)的教职员工和各自研究领域的知名专家。我将利用我的导师和科学咨询委员会成员的智力优势和学术记录，以及宾夕法尼亚大学提供的强大的专业知识、设施和资源来完成这一拟议的培训计划。

DESCRIPTION (provided by applicant): Allergic diseases such as anaphylaxis and asthma affect ~10% of Americans, and can prove fatal in children under the age of 10. Importantly, these diseases accounts for >500,000 hospitalizations annually with billions of dollars in healthcare cost. Intense research over the past 30 years has increased our understanding of the pathogenesis of asthma and other allergic diseases. It has been well established that immunoglobulin E (IgE) and mast cells play critical roles in the pathogenesis of allergic disorders. The aggregation of IgE receptor (FcϵRI) on mast cells by IgE and allergen/antigen results in the rapid release of inflammatory mediators such as histamine and leukotrienes by a process termed as "degranulation". Mast cells also release copious amounts of cytokines and chemokines, which result in the influx of other immune cells such as neutrophils, thus amplifying the allergic response. It has been recently accepted that G protein coupled receptors (GPCR) expressed on mast cells potentiate IgE-induced responses. Mast cells express the GPCR for the complement component C3a (C3aR) and mast cell-specific C3aR activation enhance IgE induced passive cutaneous anaphylaxis (PCA) and airway hyperresponsiveness (AHR) in asthma. C3aR has a class I PSD-95/Dlg/Zo1 (PDZ) binding motif in its carboxyl-terminus. Na+/H+ exchanger regulatory factors (NHERF1-4) are members of the class I family of PDZ domain proteins that bind several GPCR and regulate their trafficking and signaling. Recently, I demonstrated that NHERF1 promotes degranulation and chemokine production in C3a activated mast cells. However, NHERF1 did not interact with or affect the trafficking of C3aR. Thus, NHERF1 probably utilizes a unique and an undetermined pathway to regulate C3aR signaling in human mast cells. Moreover, whether NHERF1 regulates C3a-mediated mast cell responses in vivo, remains to be evaluated. This proposal builds up on my recent observations and aims at identifying the signaling pathway through which NHERF1 regulates human mast cell degranulation to C3a in vitro (Aim 1; mentored phase). In the independent phase, I will examine the role of NHERF1 in regulating mast cell mediated in vivo responses such as PCA (Aim 2) and AHR and lung inflammation in a mouse model of asthma (Aim 3). The completion of the proposed studies will help define the direct axis of NHERF1 in mast cells and allergic responses in vivo and will provide insights into the future development of NHERF1 antagonists that can target not only anaphylaxis and asthma but also other mast cell mediated allergic diseases. My mentoring team will consist of Dr. Hydar Ali (primary mentor), Dr. John D. Lambris (co-mentor) and Drs. Bruce Freedman, Raynold A. Panettieri, and Taku Kambayashi (Scientific Advisory Committee), all faculty members at the University of Pennsylvania (Penn) and renowned experts in their respective fields of investigation. I will take advantage of the intellectual strength and academic track record of my mentors and scientific advisory committee members, and the robust availability of expertise, facilities, and resources offered at Penn to accomplish this proposed training program.