Verapamil limits inflammation by restoring VGCC-driven epithelial Ca2+ in models of cystic fibrosis

Rationale In cystic fibrosis (CF), caused by mutations in the CFTR gene, excessive neutrophilic inflammation drives lung damage and premature mortality. Current anti-inflammatory therapies have limited efficacy, partly due to an incomplete understanding of the mechanisms underlying CF-associated inflammation. Increased epithelial Ca²⁺ signaling has been implicated, but how CFTR dysfunction perturbs the CFTR/Ca²⁺ axis to promote inflammation remains unclear. Objectives Using Cftr-depleted zebrafish and human approaches, we sought to i) define how CFTR dysfunction alters epithelial Ca²⁺ signaling and promotes inflammation, and ii) assess whether Ca²⁺ channel antagonists can attenuate inflammatory damage in CF. Methods and Results We generated a transgenic zebrafish line expressing the Ca²⁺ reporter GCaMP6 under an epithelial promoter to dynamically map epithelial Ca²⁺ activity in vivo . Cftr-depleted zebrafish exhibited exaggerated epithelial Ca²⁺ elevations following injury compared with wild-type animals. Genetic or pharmacological inhibition of L-type voltage-gated Ca²⁺ channels (VGCCs) normalized epithelial Ca²⁺ responses and reduced both oxidative stress and neutrophil recruitment. Among FDA-approved VGCCs antagonists tested, only verapamil promoted resolution of neutrophilic inflammation and improved tissue repair in CF zebrafish. Mechanistically, verapamil reduced aberrant epithelial Ca²⁺ fluxes, ROS generation and NF-κB activation. These effects were confirmed in the human CF epithelial cell CFBE41o⁻, where verapamil reduced Ca 2+ and oxidative stress. Conclusions These findings establish dysregulated Ca²⁺ signaling via L-type VGCCs as a pathogenic driver of inflammation in CF and identify verapamil as a promising therapeutic candidate. By restoring Ca²⁺ and oxidative homeostasis, verapamil alleviates inflammatory damage, supporting its repurposing as a candidate anti-inflammatory therapy in CF.