Molecular Characterization of GPR35 and GPR55, Putative Cannabinoid Receptors

描述（由申请人提供）：许多与疼痛和成瘾有关的G蛋白偶联受体已在生物学和生物化学上得到了很好的表征，但一些孤儿受体如GPR35和GPR55与已知的滥用药物受体具有同源性，其表征仍然很差。GPR55正在成为炎性疼痛、神经性疼痛和骨发育的重要靶点，而其他研究表明GPR55活化是促癌的。GPR55确实识别某些大麻素配体，因此它被认为是第三种大麻素受体。 GPR35是疼痛（脊髓抗伤害感受以及炎性疼痛）、心脏病、哮喘、代谢疾病、炎性肠病和癌症中的重要靶标。这些区域中的每一个单独在医学上都是重要的，并且每一个都将受益于使用选择性激动剂和拮抗剂以在其各自的动物模型中进行进一步研究。 然而，到目前为止，没有低纳摩尔效力的配体已被发现这些受体，也没有开发的放射性配体来表征结合。缺乏这样的配体是该领域进展的关键障碍。该提案的目标是利用我们最近有前途的高通量，高含量的GPR55激动剂和GPR35拮抗剂的筛选结果，使用基于结构的设计和化学信息学工具，为选定的支架开发SAR，从而鉴定保留高受体选择性的低纳摩尔配体。我们的目标是发现纳摩尔效力GPR55和GPR35配体使用基于结构的设计，分子建模，化学信息学，高通量筛选和定点诱变的组合。

DESCRIPTION (provided by applicant): Many G-protein coupled receptors involved in pain and addiction are pharmacologically and biochemically well characterized, but some orphan receptors like GPR35 and GPR55, with homology to known receptors for drugs of abuse, remain poorly characterized. GPR55 is emerging as an important target in inflammatory pain, neuropathic pain, and bone development while other studies indicate that GPR55 activation is pro-carcinogenic. GPR55 does recognize certain cannabinoid ligands, so it has been suggested to be a third cannabinoid receptor. GPR35 is an important target in pain (spinal antinociception as well as inflammatory pain), heart disease, asthma, metabolic disease, inflammatory bowel disease and cancer. Each of these areas alone is medically important and each would benefit by the use of selective agonists and antagonists to further studies in their respective animal models. However, to date, no low nanomolar potency ligands have been discovered for these receptors nor is there a radioligand developed to characterize binding. The lack of such ligands is a critical barrier to progress in this field. The goal of this proposal is to leverage our recen promising high throughput, high content screening results for GPR55 agonists and GPR35 antagonists using structure based design and cheminformatics tools to develop an SAR for selected scaffolds that leads to the identification of low nanamolar ligands that retain high receptor selectivity. We aim to discover nanomolar potency GPR55 and GPR35 ligands using a combination of structure-based design, molecular modeling, chemoinformatics, high-throughput screening and site directed mutagenesis.