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 calcium signaling has been implicated, but how CFTR dysfunction perturbs the CFTR/calcium axis to promote inflammation remains unclear. Objectives: Using Cftr-depleted zebrafish and human approaches, we sought to i) define how CFTR dysfunction alters epithelial calcium signaling and promotes inflammation, and ii) assess whether calcium channel antagonists can attenuate inflammatory damage in CF. Methods and Results: We generated a transgenic zebrafish line expressing the calcium reporter GCaMP6 under an epithelial promoter to dynamically map epithelial calcium activity in vivo. Cftr-depleted zebrafish exhibited exaggerated epithelial calcium elevations following injury compared with wild-type animals. Genetic or pharmacological inhibition of L-type voltage-gated calcium channels (VGCCs) normalized epithelial calcium 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 calcium fluxes, ROS generation and NF-κB activation. These effects were confirmed in the human CF epithelial cell CFBE41o⁻, where verapamil reduced calcium and oxidative stress. Conclusions/ These findings establish dysregulated calcium signaling via L-type VGCCs as a pathogenic driver of inflammation in CF and identify verapamil as a promising therapeutic candidate. By restoring calcium and oxidative homeostasis, verapamil alleviates inflammatory damage, supporting its repurposing as a candidate anti-inflammatory therapy in CF.