Verapamil limits inflammation by restoring VGCC-driven epithelial Ca2+ in models of cystic fibrosis
RationaleIn 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 Ca{superscript 2} signaling has been implicated, but how CFTR dysfunction perturbs the CFTR/Ca{superscript 2} axis to promote inflammation remains unclear. ObjectivesUsing Cftr-depleted zebrafish and human approaches, we sought to i) define how CFTR dysfunction alters epithelial Ca{superscript 2} signaling and promotes inflammation, and ii) assess whether Ca{superscript 2} channel antagonists can attenuate inflammatory damage in CF. Methods and ResultsWe generated a transgenic zebrafish line expressing the Ca{superscript 2} reporter GCaMP6 under an epithelial promoter to dynamically map epithelial Ca{superscript 2} activity in vivo. Cftr-depleted zebrafish exhibited exaggerated epithelial Ca{superscript 2} elevations following injury compared with wild-type animals. Genetic or pharmacological inhibition of L-type voltage-gated Ca{superscript 2} channels (VGCCs) normalized epithelial Ca{superscript 2} 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 Ca{superscript 2} fluxes, ROS generation and NF-{kappa}B activation. These effects were confirmed in the human CF epithelial cell CFBE41o-, where verapamil reduced Ca2+ and oxidative stress. ConclusionsThese findings establish dysregulated Ca{superscript 2} signaling via L-type VGCCs as a pathogenic driver of inflammation in CF and identify verapamil as a promising therapeutic candidate. By restoring Ca{superscript 2} and oxidative homeostasis, verapamil alleviates inflammatory damage, supporting its repurposing as a candidate anti-inflammatory therapy in CF.