Cysteinyl leukotriene signaling in proliferation, cytokine production and PGD2 ge

描述(申请人提供)：Cys-Lts是强有力的支气管收缩药、血管渗漏的强有力的诱导剂和呼吸道高反应性的增强剂，在哮喘中起重要作用。MCs在哮喘中作为效应细胞的重要性使得了解Cys-LTs调节MCs功能的基本机制势在必行。LTE4虽然是Cys-LTs中最丰富和最稳定的，但对已知的CysLTRs是一种弱的部分激动剂，但在体内诱导出不能由LTC4或LTD4概括的独特反应。我们的初步研究表明，LTE4有效地刺激HMCs的细胞增殖、细胞因子的产生和COX-2依赖的PGD2的产生，这是传统的CysLTRs无法解释的。阻断PPAR3或P2Y12受体可以消除LTE4诱导的LAD2细胞中MIP-12的产生和PGD2的反应。此外，在体内，与LTD4不同，LTE4可以放大由P2Y12受体介导的低剂量过敏原在致敏BALB/c小鼠体内引发的粘膜炎症。这表明，与普遍认为的LTD4是Cys-LT的主要效应者相反，LTE4可能在粘膜和血管炎症中具有中心和独特的作用。在本文中，我们假设：1.不同的PKC介导CysLTR介导的反应；2.LTE4不同于其前体，它通过依赖PPAR-3的机制刺激强信号，其反应涉及CysLT1样受体、P2Y12受体和PPAR-3的贡献。我们试图确定参与这些反应的信号中间体，并分析其对肥大细胞功能的影响。Cys-Lts和MC衍生的主要二十烷类化合物PGD2在人类哮喘的病理过程中含量丰富，并诱导和放大了小鼠实验性变态反应性肺部炎症。尽管这些调解人类别在相同的背景下参与，但对它们之间的交叉监管知之甚少。Cys-LTs在粘膜炎症中显著调节MC的发展，提示局部来源的Cys-LTs可能通过作用于MC来控制PGD2的产生。如果正确，这可能对哮喘和过敏性疾病，特别是对Th2反应的控制具有重大的病因学和治疗意义。 公共卫生相关性：这项建议试图确定一种常见的脂质调节剂白三烯E4如何调节肥大细胞的激活，肥大细胞是调节炎症反应的重要细胞，对过敏原和感染性物质的反应。研究这一点可以帮助我们更好地理解和治疗哮喘和其他过敏症。

DESCRIPTION (provided by applicant): Cys-LTs are potent bronchoconstrictors, powerful inducers of vascular leakage and potentiators of airway hyperresponsiveness and play an essential role in asthma. The importance of MCs as effector cells in asthma makes it imperative to understand the basic mechanisms by which the cys-LTs regulate the function of MCs. LTE4, though the most abundant and stable of the cys-LTs, is a weak, partial agonist for the known CysLTRs, but induces unique responses in vivo that cannot be recapitulated by LTC4 or LTD4. Our preliminary Studies indicate that LTE4 potently stimulates cell proliferation, cytokine production, and COX-2-dependent PGD2 generation in hMCs that are not explained by the conventional CysLTRs. Blocking PPAR3 or P2Y12 receptor abrogates LTE4-induced MIP-12 generation as well as PGD2 response in LAD2 cells. Complimenting this, in vivo LTE4 unlike LTD4 amplifies mucosal inflammation induced by low-dose allergen in sensitized BALB/c mice that is mediated by the P2Y12 receptor. This suggest that contrary to the widely held belief that LTD4 is the major effector cys- LT, LTE4 may have a central and unique role in mucosal and vascular inflammation. In the present grant, we hypothesize that 1. Different PKCs mediate CysLTR-mediated responses and 2. LTE4 differs from its precursors by stimulating strong signaling through a PPAR-3-dependent mechanism and its responses involve contributions from CysLT1-like receptors, P2Y12 receptor and PPAR-3. We attempt to identify signaling intermediates involved in these responses and analyze the effects on mast cell functions. Both cys-LTs and the major MC-derived eicosanoid, PGD2, are abundant in the pathology of asthma in humans both induce and amplify experimental allergic pulmonary inflammation in mice. Although these mediator classes participate in the same contexts, little is known regarding cross-regulation between them. The fact that cys-LTs prominently regulate MC development in mucosal inflammation suggests that locally-derived cys-LTs could control PGD2 production through actions on MCs. If correct, this could carry substantial pathogenetic and therapeutic implications for asthma and allergic diseases in particular and control of Th2 responses. PUBLIC HEALTH RELEVANCE: This proposal seeks to determine how a common lipid mediator leukotriene E4 can regulate the activation of mast cells, important cells mediating the inflammatory responses in response to allergens and infectious agents. Studying this could help us in better understanding and treatment strategies for asthma and other allergies.