The role of membrane trafficking regulation for mast cell-mediated allergic disorders

过敏症是一个严重且日益严重的公共卫生问题。过敏性疾病中的关键效应器功能由肥大细胞介导。在过敏原诱导的活化后，肥大细胞迅速去活化并释放大量炎症介质，这些介质协调过敏反应。肥大细胞活化过程中的颗粒胞吐作用需要一系列高度有序和严格调控的膜运输事件。肥大细胞脱粒过程中这些重要步骤中的任何一个的扰动都可能对肥大细胞功能产生严重后果。因此，有强烈的兴趣在解开最终调节肥大细胞脱粒和介质释放的细胞过程，因为它可能提供肥大细胞介导的过敏性疾病的新的治疗靶点。然而，尽管所有的努力，许多基本的分子和细胞机制，调节囊泡运输过程中肥大细胞脱粒仍然知之甚少。我们的研究小组深入研究膜运输过程中的免疫细胞信号和功能的作用。为了表征肥大细胞脱颗粒的新的调节机制，并研究其与过敏/过敏反应的生理相关性，我们在这里提出研究两种不同的调节膜运输，溶胞素和Rin 3，在肥大细胞生物学中的作用。我们小组的初步工作已经有力地表明了这些分子在肥大细胞中的关键作用。为了确定肥大细胞介导的过敏反应中Lyst和Rin 3的功能，我们将采用双重策略，其中细胞生物学和机制的体外研究通过使用Lyst和Rin 3缺陷小鼠体内过敏反应分析来补充。该提案的主要目的是表征溶酶体运输调节剂Lyst对肥大细胞颗粒组织/结构的作用及其对肥大细胞介导的过敏/速发过敏反应的功能影响。此外，我们还将进行详细的功能和机制的Rab 5特异性鸟嘌呤核苷酸交换因子Rin 3的肥大细胞介质释放和过敏反应的作用分析。总之，关于膜运输调节剂对肥大细胞功能的作用的拟议实验不仅将为肥大细胞脱粒的复杂调节机制提供新的见解，而且还可能揭示这些过程中的扰动如何有助于过敏性疾病的病理生理学。此外，该项目的财政支持将培养一位有前途的年轻科学家Andreas Westphal，他刚在李教授的实验室完成博士学业。Andreas Westphal对Lyst在先天免疫细胞中的作用的出色研究为所提出的研究提供了基础，并为他赢得了我们最近在Journal of Experimental Medicine（Westphal et al.，JEM，2016）。

Allergies pose a serious and increasing public health problem. Critical effector functions in allergic disease are mediated by mast cells. Upon allergen-induced activation, mast cells rapidly degranulate and release a multitude of inflammatory mediators that orchestrate the allergic reaction. Granule exocytosis during mast cell activation requires a series of highly ordered and tightly regulated membrane trafficking events. Perturbation of any of these vital steps during mast cell degranulation can have severe consequences for mast cell function. Thus, there is intense interest in unraveling the cellular processes that ultimately regulate mast cell degranulation and mediator release, as it may provide novel therapeutic targets for mast cell-mediated allergic disorders. However, despite all efforts, many of the basic molecular and cellular mechanisms that regulate vesicle trafficking during mast cell degranulation are still poorly understood.Our research group intensively studies the role of membrane trafficking processes for immune cell signaling and function. To characterize novel regulatory mechanisms of mast cell degranulation and to investigate their physiological relevance for allergic/anaphylactic reactions, we here propose to study the roles of two distinct regulators of membrane trafficking, Lyst and Rin3, in mast cell biology. Preliminary work by our group already strongly indicates a critical role of these molecules in mast cells. To define the function of Lyst and Rin3 in mast cell-mediated allergic reactions, we will employ a dual strategy, in which cell biological and mechanistic in vitro studies are complemented by analysis of anaphylactic reactions in vivo utilizing Lyst- and Rin3-deficient mice. Major aims of the proposal are the characterization of the role of lysosomal trafficking regulator Lyst for mast cell granule organization/structure and its functional impact on mast cell-mediated allergic/anaphylactic reactions. Moreover, we will also perform a detailed functional and mechanistic analysis of the role of the Rab5-specific guanine nucleotide exchange factor Rin3 for mast cell mediator release and anaphylactic reactions. Together, the proposed experiments on the role of membrane trafficking regulators for mast cell function will not only provide novel insights into the complex regulatory mechanisms of mast cell degranulation, but may also reveal how perturbations in these processes can contribute to the pathophysiology of allergic disease.In addition, financial support of the project will foster a promising young scientist, Andreas Westphal, who is just finishing his PhD studies in Prof. Lees laboratory. Andreas Westphals excellent studies on the role of Lyst in innate immune cells provide the basis for the proposed studies and have earned him a first authorship on our recent publication in the Journal of Experimental Medicine (Westphal et al., JEM, 2016).