Molecular Characterization of GPR35 and GPR55, Putative Cannabinoid Receptors

描述（由申请人提供）：许多参与疼痛和成瘾的g蛋白偶联受体在药理学和生物化学上都得到了很好的表征，但一些孤儿受体，如GPR35和GPR55，与已知的滥用药物受体同源，仍然缺乏表征。GPR55正成为炎症性疼痛、神经性疼痛和骨骼发育的重要靶点，而其他研究表明，激活GPR55具有促致癌作用。GPR55确实能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（脊柱抗痛和炎症性疼痛）、心脏病、哮喘、代谢性疾病、炎症性肠病和癌症的重要靶点。这些领域中的每一个都具有重要的医学意义，并且通过使用选择性激动剂和拮抗剂在各自的动物模型中进一步研究，每个领域都将受益。然而，到目前为止，还没有发现这些受体的低纳摩尔效配体，也没有开发出表征结合的放射性配体。缺乏这样的配体是这一领域取得进展的关键障碍。本提案的目标是利用我们最近对GPR55激动剂和GPR35拮抗剂的高通量、高含量筛选结果，利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，从而鉴定出具有高受体选择性的低纳米摩尔配体。我们的目标是利用基于结构的设计、分子建模、化学信息学、高通量筛选和定点诱变相结合的方法来发现纳米级的GPR55和GPR35配体。

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.