Orphan GPCRs of the GPRC5 family regulate macrophage activity and vascular contractility by dimerizing with other GPCRs, but pharmacological modulation of this process has not been explored. We previously identified the dimerization interface of receptor GPRC5B and show here that both its mutation and inhibition by a decoy peptide disturbed the interaction with the prostaglandin E2 receptor EP2 in macrophages, resulting in reduced EP2 signaling, enhanced migration and phagocytosis, and protection from bacterial peritonitis in mice. Furthermore, we show that a similar interface exists in related receptor GPRC5C, and, the same as in GPRC5B, mutation or inhibition by decoy peptide improved host defense. Through a virtual docking screen, we identified a small molecule inhibitor of both GPRC5B and GPRC5C dimerization, K303MP20, and showed that it reduced EP2 signaling, enhanced macrophage activity, and improved host defense in bacterial peritonitis and influenza A infection. Interestingly, K303MP20 not only blocked dimerization between GPRC5B/C and EP2, but also with prostacyclin receptor IP and angiotensin II receptor AT1, resulting in reduced AT1-dependent contraction and enhanced IP-dependent relaxation in human and murine smooth muscle cells. In vivo, K303MP20 did not affect basal blood pressure, but protected mice from angiotensin II–induced hypertension. Taken together, inhibition of orphan GPCR dimerization by small molecules is feasible and improves infection control and arterial hypertension.
Jeonghyeon Kwon, Margherita Persechino, Jingchen Shao et al.· Journal of Clinical Investig...· 0 citations
Peptide-activated G protein-coupled receptors (GPCRs) play crucial roles in numerous diseases, but remain difficult therapeutic targets due to the challenges in developing small-molecule drugs. Here, we explore structure-based strategies to identify small-molecule agonists of neurotensin (NTS) receptors, which hold promise for developing non-opioid analgesics. Chemical libraries of drug-like molecules are first designed based on a receptor-peptide complex, and then 14.5 million compounds are computationally docked to the orthosteric binding site of the NTS1 receptor. A set of 39 top-ranked compounds is synthesized, and seven of these are experimentally confirmed to activate the NTS1 receptor. Structure-guided optimization yields NTS1 ligands with signaling signatures distinct from the endogenous peptide, and these compounds also exhibit high affinity for the NTS2 receptor. High-resolution crystal structures of two agonists bound to the NTS1 receptor confirm predicted binding modes and reveal key determinants of activation. In vivo, the compounds produce robust antinociception in rodents without inducing hypotension, consistent with a contribution of NTS2 receptor activity. To facilitate broader application of our virtual screening approach to peptide-binding GPCRs, we provide access to tailored chemical libraries containing billions of readily synthesizable compounds. In this work, small-molecule ligands of neurotensin receptors were identified using structure-based virtual screening, leading to the discovery of potent agonists with in vivo antinociceptive effects and to insights into the molecular basis of receptor activation.
Nicolas Panel, D. D. Vo, Harald Hübner et al.· Nature Communications· 0 citations
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