"Relative symmetry with electronegativity of different key-groups" strategy for MRGPRX2 antagonist design and its effect on antigen-induced pulmonary inflammation.

MRGPRX2 antagonists possess the potential for the treatment of allergic rhinitis, atopic dermatitis, and chronic urticaria. Previously, we identified a class of diaryl urea (DPU) MRGPRX2 antagonists with sub-micromolar IC(50) values in vitro. However, the structure-activity relationship remains unclear. Herein, we adopted a "relative symmetry with electronegativity of different key-groups" strategy for further modification of DPUs to achieve a promising MRGPRX2 antagonist with higher activity and safety. Electrostatic potential energy analysis and biological evaluation revealed that B-1023 and B-5023, that possess relatively symmetric electron-withdrawing substituents, remarkable inhibited mast cell degranulation at a sub-micromolar IC(50) in vitro and alleviated anaphylactic symptoms. Furthermore, B-1023, mitigated antigen-induced pulmonary inflammation (AIPI) in mice and competitively bonded to MRGPRX2. In summary, the "relative symmetry with electronegativity of different key-groups" strategy provided a drug design pattern for MRGPRX2 antagonists and identified promising antiallergic precursors for AIPI treatment.