Novel strategies for asthma therapy by regulating mast cell signaling by MyD88

描述（由申请人提供）：哮喘是一种复杂的气道炎性疾病，其特征为支气管收缩、气道高反应性和炎症。有大量证据表明肥大细胞高亲和力IgE受体（FceRI）在哮喘发病机制中的重要作用。因此，巨大的努力已被导向理解的信号转导途径，通过该受体的功能进行调节。越来越多的证据表明，上皮细胞来源的细胞因子如白细胞介素-33（IL-33）和细菌脂多糖（LPS）通过激活各自的受体ST 2和TLR 4在哮喘急性加重中起重要作用，但其作用机制尚不清楚。髓样分化因子（MyD）88是传递IL-33和LPS信号的最近端衔接分子。我们发现MyD 88不仅调节肥大细胞中的IL-33和LPS信号传导，还促进抗原/IgE介导的蛋白激酶B（Akt）磷酸化和细胞因子产生。我们还发现LPS或IL-33与抗原/IgE协同产生细胞因子，并且这种串扰在MyD 88-/-肥大细胞中几乎被消除。基于这些发现，我们推测MyD 88通过调节和交叉调节肥大细胞中的Fc 5 RI信号来促进过敏性炎症。本研究的两个具体目标是进一步探讨MyD 88在体外肥大细胞信号转导和小鼠过敏性炎症模型中的作用。在目标#1中，我们将使用逆转录病毒用野生型或遗传修饰的MyD 88转染MyD 88-/-肥大细胞，以描述这种衔接子分子如何调节和交叉调节肥大细胞中的FceRI信号传导。在目标#2中，我们将首先检验肥大细胞中表达的MyD 88介导体内过敏性炎症的假设。然后，我们将调节肥大细胞中的MyD 88信号传导，并确定这种调节对过敏性炎症的影响。我们相信，拟议的研究将产生关于肥大细胞中FceRI信号传导的调节和交叉调节的重要新信息，并可能为治疗哮喘和其他过敏性疾病提供新的治疗方法。公共卫生相关性：哮喘是一种以支气管收缩、气道高反应性和炎症反应为特征的复杂气道炎症性疾病。据估计，大约有1700万美国人患有哮喘，其中三分之一是儿童。近年来，哮喘的患病率和严重程度在世界范围内急剧增加。肥大细胞释放炎症介质，导致哮喘和其他过敏性疾病的症状。这项建议是基于一个新的分子，调节肥大细胞功能的鉴定。我们相信，拟议的研究将产生重要的新信息调节肥大细胞功能，并可能提供新的治疗方法，治疗哮喘和其他过敏性疾病。

DESCRIPTION (provided by applicant): Asthma is a complex airway inflammatory disease characterized by bronchoconstriction, airway hyperresponsiveness and inflammation. There is a substantial body of evidence that demonstrates an important role for mast cell high affinity IgE receptor (FceRI) in the pathogenesis of asthma. Therefore, tremendous efforts have been directed towards understanding the signaling pathway via which function of this receptor is regulated. Emerging evidence suggests that epithelial cell-derived cytokine such as interleukin-33 (IL-33) and bacterial lipopolysaccharide (LPS) play important roles in asthma exacerbation via the activation of their respective receptors ST2 and TLR4 but the mechanisms of their action remains unknown. Myeloid differentiation factor (MyD) 88 is the most proximal adapter molecule that transmits signal for both IL-33 and LPS. We made the novel observation that MyD88 not only regulates IL-33 and LPS signaling in mast cells, it also contributes to antigen/IgE-mediated protein kinase B (Akt) phosphorylation and cytokine production. We also found that LPS or IL-33 synergizes with antigen/IgE for cytokine generation and that this cross-talk is almost abolished in MyD88-/- mast cells. Based on these findings, we hypothesize that MyD88 promotes allergic inflammation by regulating and cross-regulating Fc5RI signaling in mast cells. Two specific aims are proposed to further explore the role of MyD88 on mast cell signaling in vitro and murine model of allergic inflammation in vivo. In aim #1, we will use retrovirus to transfect MyD88-/- mast cells with wild-type or genetically modified MyD88 to delineate how this adapter molecule regulates and cross-regulates FceRI signaling in mast cells. In aim #2, we will first test the hypothesis that MyD88 expressed in mast cells mediates allergic inflammation in vivo. We will then modulate MyD88 signaling in mast cells and determine the impact of this modulation on allergic inflammation. We believe that proposed studies will generate significant new information on the regulation and cross-regulation of FceRI signaling in mast cells and may offer novel therapeutic approaches for the treatment of asthma and other allergic diseases. PUBLIC HEALTH RELEVANCE: Asthma is a complex airway inflammatory disease characterized by bronchoconstriction, airway hyperresponsiveness and inflammation. Approximately 17 million Americans are estimated to have asthma, one third of them children. In recent years, asthma prevalence and severity have been increasing dramatically world-wide. Mast cells release inflammatory mediators that cause the symptoms of asthma and other allergic diseases. This proposal is based on the identification of a new molecule that regulates mast cell function. We believe that proposed studies will generate significant new information on the regulation of mast cell function and may offer novel therapeutic approaches for the treatment of asthma and other allergic diseases.