1. Inhibition of ATP hydrolysis restores airway surface liquid production in cystic fibrosis airway epithelia
- Author
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Wanda K. O'Neal, Holger Stephan, Hong Dang, Neil E. Alexis, Richard C. Boucher, Wayne Anderson, Scott H. Donaldson, Brian Button, Lisa C. Morton, Catharina van Heusden, Agathe Ceppe, and Eduardo R. Lazarowski
- Subjects
0301 basic medicine ,Pulmonary and Respiratory Medicine ,Cystic Fibrosis ,Physiology ,Regulator ,Bronchi ,Respiratory Mucosa ,Cystic fibrosis ,03 medical and health sciences ,Adenosine Triphosphate ,0302 clinical medicine ,ATP hydrolysis ,Physiology (medical) ,medicine ,Humans ,Enzyme Inhibitors ,Adenosine Triphosphatases ,Chemistry ,Hydrolysis ,Sputum ,Epithelial Cells ,Cell Biology ,Tungsten Compounds ,Alkaline Phosphatase ,medicine.disease ,Molecular biology ,Transmembrane protein ,030104 developmental biology ,030228 respiratory system ,Lung disease ,Airway ,Research Article - Abstract
Airway surface dehydration is a pathological feature of cystic fibrosis (CF) lung disease. CF is caused by mutations in the CF transmembrane conductance regulator (CFTR), a cyclic AMP-regulated Cl− channel controlled in part by the adenosine A2B receptor. An alternative CFTR-independent mechanism of fluid secretion is regulated by ATP via the P2Y2 receptor (P2Y2R) that activates Ca2+-regulated Cl− channels (CaCC/TMEM16) and inhibits Na+ absorption. However, due to rapid ATP hydrolysis, steady-state ATP levels in CF airway surface liquid (ASL) are inadequate to maintain P2Y2R-mediated fluid secretion. Therefore, inhibiting airway epithelial ecto-ATPases to increase ASL ATP levels constitutes a strategy to restore airway surface hydration in CF. Using [γ32P]ATP as radiotracer, we assessed the effect of a series of ATPase inhibitory compounds on the stability of physiologically occurring ATP concentrations. We identified the polyoxometalate [Co4(H2O)2(PW9O34)2]10− (POM-5) as the most potent and effective ecto-ATPase inhibitor in CF airway epithelial cells. POM-5 caused long-lasting inhibition of ATP hydrolysis in airway epithelia, which was reversible upon removal of the inhibitor. Importantly, POM-5 markedly enhanced steady-state levels of released ATP, promoting increased ASL volume in CF cell surfaces. These results provide proof of concept for ecto-ATPase inhibitors as therapeutic agents to restore hydration of CF airway surfaces. As a test of this notion, cell-free sputum supernatants from CF subjects were studied and found to have abnormally elevated ATPase activity, which was markedly inhibited by POM-5.
- Published
- 2020