H2O2 stimulates cystic fibrosis transmembrane conductance regulator through an autocrine prostaglandin pathway, using multidrug-resistant protein-4

• Published in: American journal of respiratory cell and molecular biology Vol. 49; no. 4; pp. 672 - 679
• Main Authors: Conner, Gregory E, Ivonnet, Pedro, Gelin, Murline, Whitney, Philip, Salathe, Matthias
• Format: Journal Article
• Language: English
• Published: United States American Thoracic Society 01.10.2013
• Subjects: Anions - metabolism; Bronchi - drug effects; Bronchi - metabolism; Cell Membrane - drug effects; Cell Membrane - metabolism; Cells, Cultured; Cyclic AMP - metabolism; Cyclooxygenase Inhibitors - pharmacology; Cystic Fibrosis - metabolism; Cystic Fibrosis Transmembrane Conductance Regulator - metabolism; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Humans; Hydrogen Peroxide - pharmacology; Multidrug Resistance-Associated Proteins - metabolism; Prostaglandin-Endoperoxide Synthases - metabolism; Receptors, Prostaglandin E, EP1 Subtype - metabolism; Receptors, Prostaglandin E, EP4 Subtype - metabolism
• ISSN: 1044-1549; 1535-4989
• DOI: 10.1165/rcmb.2013-0156OC

Cystic fibrosis transmembrane conductance regulator (CFTR) activity is essential for the maintenance of airway surface liquid depth, and therefore mucociliary clearance. Reactive oxygen species, increased during inflammatory airway diseases, alter CFTR activity. Here, H2O2 levels in the surface liquid of normal human bronchial epithelial cultures differentiated at the air-liquid interface were estimated, and H2O2-mediated changes in CFTR activity were examined. In Ussing chambers, H2O2-induced anion currents were sensitive to the CFTR inhibitors CFTRinh172 and GlyH-101. These currents were absent in cells from patients with cystic fibrosis. Responses to greater than 500 μM H2O2 were transient. Cyclooxygenase inhibitors blocked the H2O2 response, as did EP1 and EP4 receptor antagonists. A multidrug-resistant protein (MRP) inhibitor and short hairpin RNA directed against MRP4 blocked H2O2 responses. EP1 and EP4 agonists mimicked H2O2 in both control and MRP4 knockdown cells. Thus, H2O2 activates the synthesis, export, and binding of prostanoids via EP4 and, interestingly, EP1 receptors in normal, differentiated human airway epithelial cells to activate cyclic adenosine monophosphate pathways that in turn activate CFTR channels in the apical membrane.