Cx43 levels guide apicobasal polarity in regenerating airway epithelial cells.

Apicobasal polarity plays key roles in airway epithelial maturation and regeneration. Once polarized, the airway epithelium functions as a barrier against opportunistic pathogens. Yet, the mechanisms that temporally regulate polarization, a process which is disrupted in cystic fibrosis (CF), remain unclear. Here, we demonstrate the functional importance of connexin 43 (Cx43), a gap junction protein, which is normally repressed during regeneration of the airway epithelium. We show that prolonged post-transcriptional stabilization of Cx43 leads to altered collective cell orientation and compromised CF airway epithelial barrier. We report a bidirectional cooperation between Cx43 hemichannel function and adenosine signaling in disrupting ER-Golgi secretory axis, cytoskeleton dynamic and ectopic apical fibronectin production. Genetic and pharmacological inhibition of Cx43 channels re-established polarity and spatial organization of CF airway epithelial cells. Finally, targeting Cx43 hemichannels with mimetic peptides normalizes the CF-dependent fibronectin ectopic expression and prevents the enhanced Pseudomonas aeruginosa trapping to the CF epithelium. Our findings reveal a mechanism in which temporally controlled Cx43-mediated intercellular communication is crucial for coordinating intrinsic polarity programs and maintaining airway epithelium integrity.