Research on the Intervention of Bile Stasis-Induced Pruritus Using Small Molecules Targeting MRGPRX4 Through High-Throughput Screening

MRGPRX4, which is mainly expressed in human sensory neurons, is a key mediator of cholestatic pruritus, but clinically available small-molecule inhibitors targeting it remain very scarce; thus, this study aims to screen out novel active inhibitors targeting MRGPRX4. In this work, we performed high-throughput virtual screening of the small-molecule compound library with Schrodinger software targeting MRGPRX4, and selected the top five commercially available compounds with the highest scores from 13,144 candidate compounds. Molecular docking and molecular dynamics simulation were used for virtual validation, and the results confirmed that all five compounds could bind to MRGPRX4, among which 6′-O-malonyldaidzin showed the most favorable binding free energy and a compact binding pocket with the lowest SASA value. We further verified the effect of these compounds on Ca2+ influx in 50 μM concentration in HEK293 cells overexpressing MRGPRX4, and confirmed the inhibitory activity of 6′-O-malonyldaidzin, whose binding interaction with MRGPRX4 was additionally verified by CETSA. In conclusion, this study identified 6′-O-malonyldaidzin as a promising lead compound for further pharmacological characterization and lead optimization, with potential for development as a targeted intervention for cholestatic pruritus.