Structure, pharmacology and signaling of G protein-coupled receptors (GPCRs) in inflammation

项目摘要 炎症是一个复杂的过程，涉及多种脂质和多肽介质。其中有大量的 介质通过作用于G蛋白偶联而引起促炎或促分解作用 受体(GPCRs)。我们的研究集中在一组GPCR作为亲缘关系密切的系统发育邻域 包括促炎症介质的受体，包括过敏性毒素、甲酰肽和 前列腺素D2(PGD2)和新发现的专门化促分解脂质介质(SPM)，包括 脂氧素A4(LXA4)和溶血素。这个gpr家族的成员是开发新药的积极靶点。 治疗各种炎症性疾病。到目前为止，还没有关于这个家庭的结构的报道。因此，我们的 对配体作用、受体激活和信号转导的分子机制的理解是相当深入的 有限，这阻碍了药物开发。为了填补这一知识空白，最近我们获得了晶体 该家族中C5a受体(C5aR)和前列腺素D2受体2的结构 (CRTH2)。这两个结构提供了关于C5aR和C5aR拮抗的创新信息。 CRTH2。我们建议进一步定义不同药理作用的分子决定因素。 通过测试基于我们结构的新假设来抑制C5aR和CRTH2拮抗剂。我们要吃蛋白质 结晶学和电子显微镜(EM)并行获得高分辨结构的方法 活性C5aR和CRTH2与激动剂和Gi蛋白的复合体。结果将揭示出结构 激动剂结合和受体激活的基础。此外，我们还建议开发小分子拮抗剂。 通过基于结构的药物设计(SBDD)方法，为C5aR和CRTH2提供新的化学支架。我们 还将测试开发新的C5aR和CRTH2细胞外构象抗体的可能性 阻断促炎信号通路的药理工具。我们的长期目标是朝着 C5aR和CRTH2类新药的临床研究另一个长期的研究方向是 研究介导促分解信号通路以促进炎症消退的GPCRs。FPR2/ALX (甲酰肽受体2/LXA4受体)将是我们的主要研究目标。FPR2/ALX可以作为目标 结构上不相关的介体数量，用于调节促炎或促解反应。 对该受体的研究旨在揭示不同配体作用的结构基础和 功能选择性的分子机理。我们的研究对健康具有重要意义，因为这些发现 将促进开发抗炎和促进消炎的创新药理工具 许多炎症性疾病的治疗策略。

Project Summary Inflammation is a complex process with many lipid and peptide mediators involved. A large number of these mediators elicit either pro-inflammatory or pro-resolving effects through the action on G protein-coupled receptors (GPCRs). Our research is focused on a group of GPCRs as close phylogenetic neighbors, which comprises receptors for the pro-inflammatory mediators including anaphylatoxins, formylpeptides and prostaglandin D2 (PGD2), and the newly discovered specialized pro-resolving lipid mediators (SPMs) including lipoxin A4 (LXA4) and resolvins. The members of this GPCR family are active targets for developing new drugs for a variety of inflammatory diseases. So far no structures have been reported for this family. Thus our understanding of the molecular mechanisms underlying ligand action, receptor activation and signaling is quite limited, which has impeded drug development. To fill this knowledge gap, recently we have obtained crystal structures of two members in this family, the C5a receptor (C5aR) and the prostaglandin D2 receptor 2 (CRTH2). These two structures provided innovative information regarding the antagonism of C5aR and CRTH2. We propose to further define the molecular determinants for the diverse pharmacological action of C5aR and CRTH2 antagonists by testing novel hypotheses based our structures. We will take protein crystallography and electron microscopy (EM) approaches in parallel to obtain high-resolution structures of active C5aR and CRTH2 in complex with agonists and the Gi protein. The results will reveal the structural basis of agonist binding and receptor activation. In addition, we propose to develop small-molecule antagonists with new chemical scaffolds for C5aR and CRTH2 through structure-based drug design (SBDD) approach. We will also test the possibility of developing extracellular conformational antibodies of C5aR and CRTH2 as new pharmacological tools to block pro-inflammatory signaling pathways. The long-term goal is to move towards the clinical investigation of such new agents for C5aR and CRTH2. Another long-term research direction is to study GPCRs that mediate pro-resolving signaling pathways to promote inflammation resolution. FPR2/ALX (formylpeptide receptor 2/LXA4 receptor) will be our primary research target. FPR2/ALX can be targeted by a number of structurally unrelated mediators to mediate either pro-inflammatory or pro-resolving responses. Research on this receptor is aimed to reveal the structural basis for the action of diverse ligands and the molecular mechanism for the functional selectivity. Our study is significant for health because the discoveries will facilitate the development of innovative pharmacological tools for both anti-inflammatory and pro-resolving therapeutic strategies in the treatment of many inflammatory diseases.