Development of G Protein-Coupled Receptor 183 Benzimidazole Antagonists Utilizing a Core-Hopping Approach

G protein-coupled receptor 183 (GPR183, EBI2) has emerged as a promising therapeutic target for neuropathic pain due to its role in neuroinflammatory signaling. Previously, our group identified SAE-14 as a potent GPR183 antagonist and lead scaffold for analgesic development. To further explore the structural requirements for receptor antagonism, a ligand-based core-hopping strategy was employed to identify novel chemotypes derived from SAE-14. Virtual screening identified a trisubstituted benzimidazole scaffold as a promising candidate for further investigation. A focused series of benzimidazole analogs was synthesized and evaluated for inhibition of 7α,25-dihydroxycholesterol (7α,25-OHC)-induced GPR183 activation using calcium mobilization assays. Several compounds exhibited potent antagonistic activity, with four analogs demonstrating comparable potency relative to SAE-14. The most active compounds displayed IC₅₀ values of 15.7, 15.8, 18.0, and 19.3 nM. Structure-activity relationship studies revealed that both electron-rich aromatic substituents and heteroaromatic moieties were well tolerated within the benzimidazole scaffold. These findings identify benzimidazole as a novel scaffold for GPR183 antagonism, expand the chemical space surrounding GPR183 inhibitors, and provide a foundation for future lead optimization efforts.