Functional rescue and AI analysis of a human inactivating GPCR mutation using a small molecule

Abstract

G protein-coupled receptors (GPCRs) carry out the majority of cellular transmembrane signaling. Many pathologies have underlying GPCR mutations, most of which cause misfolding and GPCR cell surface trafficking failure. Large libraries of existing small molecule GPCR ligands could be repurposed as pharmacological chaperones (PCs) which restore mutant GPCR folding and function, presenting an exciting alternative to complex gene repair, yet such in vivo studies are limited. Therefore, as proof-of-concept, we use one such known ligand/PC, Org42599/Org43553, to show functional rescue in mice bearing an inactivating human luteinizing hormone receptor (LHR) mutation. Mutant males had delayed puberty and Leydig cell LHR signaling impairment, however, fertility was unaffected. Mutant females had irregular estrous cycles, anovulation, abrogated ovarian LHR signaling, and complete infertility. PC treatment of mutant females restored LH signaling and estrous cyclicity. To characterize treatment efficacy, we developed an AI algorithm that reliably identified inherent differences among experimental groups, enabling functional analysis of the treatment effect in vivo. Our data set the stage to integrate AI analysis with GPCR-targeting PC molecules to treat diverse GPCR-based diseases.