Discovery and pharmacological characterization of a novel benzimidazole TRPV4 antagonist with cyanocyclobutyl moiety

GSK-Bz, a TPRV4 antagonist discovered by GSK, displayed potent in vitro TRPV4 inhibition activity, and demonstrated ability to inhibit TRPV4-mediated pulmonary edema in an in vivo rat model. In this study, a series of GSK-Bz derivatives were designed and synthesized based on our previous findings. Compound 2b with cyanocyclobutyl moiety (IC50 = 22.65 nM) was found to be 5.3-fold more potent than GSK-Bz (IC50 = 121.6 nM) in the calcium imaging experiment. Patch-clamp experiments confirmed that compound 2b (IR = 77.1%) also gave significantly improved potency on TRPV4 currents measured at -60 mV. Furthermore, 2b effectively suppressed the permeability response to LPS in HUVEC with negligible cytotoxicity (CC50 > 100 μM). The in vivo protective effects of compounds 2b on acute lung injury were finally assessed in an LPS-induced ALI mice model. Notably, 2b gave better results than HC-067047 against all of the tested indexes (lung W/D ratios, the concentrations of BALF protein and pathological scores), indicating that 2b is a novel and highly potent TRPV4 antagonist which is worth for further development. Currently, evaluation for the drug-like properties of 2b is underway.