Increased airway epithelial Na+ absorption produces cystic fibrosis-like lung disease in mice.
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene result in defective epithelial cAMP-dependent Cl(-) secretion and increased airway Na(+) absorption. The mechanistic links between these altered ion transport processes and the pathogenesis of cystic fibrosis lung disease, however, are unclear. To test the hypothesis that accelerated Na(+) transport alone can produce cystic fibrosis-like lung disease, we generated mice with airway-specific overexpression of epithelial Na(+) channels (ENaC). Here we show that increased airway Na(+) absorption in vivo caused airway surface liquid (ASL) volume depletion, increased mucus concentration, delayed mucus transport and mucus adhesion to airway surfaces. Defective mucus transport caused a severe spontaneous lung disease sharing features with cystic fibrosis, including mucus obstruction, goblet cell metaplasia, neutrophilic inflammation and poor bacterial clearance. We conclude that increasing airway Na(+) absorption initiates cystic fibrosis-like lung disease and produces a model for the study of the pathogenesis and therapy of this disease.
Pubmed ID: 15077107 RIS Download
Animals | Cystic Fibrosis | Cystic Fibrosis Transmembrane Conductance Regulator | Disease Models, Animal | Epithelial Sodium Channels | Epithelium | Humans | Lung | Mice | Mice, Inbred C3H | Mice, Inbred C57BL | Mice, Transgenic | Mucus | Sodium | Sodium Channels