Novel Synergism Between LTD4 and PGE2 Signaling in MC-medicated Inflammation

项目摘要 肥大细胞（MC）是哮喘的效应细胞，其活化引起半胱氨酰白三烯的分泌 （cys-LT）和胰高血糖素（PGs）。MC不仅分泌这些介质，而且还具有受体 让他们能够感知他们的信号Cys-LT是有效的支气管收缩剂，血管紧张素Ⅱ的强诱导剂， 泄漏，气道高反应性增强剂，并在哮喘和其他疾病中发挥重要作用 炎症性疾病另一方面，前列腺素E2（PGE 2）在哮喘领域中的功能是 有争议的作用既作为亲以及抗炎，主要取决于受体/s通过 它发挥了它的作用。我们的初步结果表明，cys-LTs与PGE 2协同作用， 通过其对MC的作用增强血管炎症（增强的钙流、c-Fos、考克斯-2、PGD 2 和巨噬细胞炎性蛋白-1 β（MIP-1 β; CCL 4））产生。有趣的是，LTD 4-PGE 2协同作用是 CysLT 1 R拮抗剂（MK 571/ singulair）和EP 3拮抗剂（L-798）联合治疗仅能阻断CysLT 1 R， 提示需要CysLT 1 R拮抗剂和EP 3阻断剂的组合来治疗炎症， 哮喘进一步地，PPARs抑制剂GW 9662与PKG抑制剂KT 5823和MEK一起沿着抑制这种协同作用 抑制剂PD 98059，暗示了PPAR γ、PKG和Erk的作用。此外，LTD 4 + PGE 2协同作用还 增强DF致敏小鼠的肺部炎症（免疫细胞、杯状细胞的募集 化生、炎性转录物的上调）。根据这些初步数据，我们假设， LTD 4具有将PGE 2信号从EP 2/Gs/cAMP/PKA途径转换到EP 3/Gi/cGMP/PKG轴的潜力， 通过PPAR γ、考克斯-2和PGD 2产生促炎信号和MC活化，然后增强 Der F攻击小鼠的肺部炎症。我们将在以下具体目标中检验这一假设1） 为了确定Cys-LT/PGE 2协同作用诱导MC活化和PGD 2的机制， 2）确定cys-LT-PGE 2的生理意义 在Der f-攻击的小鼠中体内肺部炎症的相互作用，分析病理学， 免疫应答的生理学和免疫学特征，并评估MC的贡献。 这些研究将对哮喘和过敏性疾病的致病和治疗产生重大影响 并为开发和翻译未来的治疗分子提供基础， 炎症

Project Summary Mast cells (MCs) are effector cells in asthma and their activation causes secretion of cysteinyl leukotrienes (cys-LTs) and prostaglandins (PGs). MCs not only secrete these mediators, but they also possess receptors for them, to perceive their signals. Cys-LTs are potent bronchoconstrictors, powerful inducers of vascular leakage, potentiators of airway hyper-responsiveness and play an important role in asthma and other inflammatory disorders. On the other hand, Prostaglandin E2 (PGE2) function in the field of asthma is controversial acting both as pro as well as anti-inflammatory, depending mainly on the receptor/s through which it exerts its effect. Our preliminary results indicate that cys-LTs together with PGE2 synergistically potentiate vascular inflammation through their action on MCs (enhanced calcium flux, c-Fos, COX-2, PGD2 and Macrophage Inflammatory Protein-1 (MIP-1; CCL4)) generation. Interestingly, LTD4-PGE2 synergism is blocked only by combined treatment of CysLT1R antagonist (MK571/ singulair) and EP3 antagonist (L-798), suggesting the need for a combination of CysLT1R antagonists and EP3 blockers to treat inflammation in asthma. Further, PPAR inhibitor, GW9662 inhibited this synergy along with PKG inhibitor, KT5823 and MEK inhibitor PD98059, implicating a role for PPAR, PKG and Erk. Furthermore, LTD4+PGE2 synergism also potentiates pulmonary inflammation in der f sensitized mice (recruitment of immune cells, goblet cell metaplasia, up-regulation of inflammatory transcripts). Based on these preliminary data, we hypothesize that LTD4 has a potential to switch PGE2 signals from EP2/Gs/cAMP/PKA pathway to EP3/Gi/cGMP/PKG axis, generating pro-inflammatory signals and MC activation via PPAR, COX-2 and PGD2, followed by potentiating pulmonary inflammation in der f- challenged mice. We will test this hypothesis in the following specific aims 1) To determine the mechanism by which Cys-LT/PGE2 synergism induces MC activation and PGD2 production in vitro with focus on PPAR 2) To determine the physiological significance of cys-LT-PGE2 interactions in pulmonary inflammation in vivo in Der f-challenged mice, analyzing pathologic, physiologic, and immunologic signatures of the immune response and evaluate the contribution of MCs. These studies will carry substantial pathogenic and therapeutic implications for asthma and allergic diseases as well as provide the basis for development and translation of future therapeutic molecules that regulate inflammation.