TRPV4 and chronic obstructive pulmonary disease: Importantly, diesel exhaust particles (DEP) evoked protracted Ca2+ influx via TRPV4, enhanced by the COPD-predisposing human genetic polymorphism TRPV4P19S [89] Therefore, TRPV4 antagonists may present options for cough relief, asthma, and COPD therapeutics.