Modification of transepithelial ion transport in human cultured bronchial epithelial cells by interferon-?

Human bronchial epithelial cells were treated in vitro with interferon-? or tumor necrosis factor-? to assess their effect on transepithelial ion transport. Short-circuit current measurements revealed that Na+ absorption was markedly inhibited by interferon-? (10-1,000 U/ml). The cystic fibrosis transmembrane conductance regulator was also downregulated by interferon-? as evident at the protein level and by the decrease in the cAMP-dependent current. On the other hand, interferon-? caused an increase of the current elicited by apical UTP application, which is due to the activity of Ca2+-dependent Cl-channels. Tumor necrosis factor-? caused few changes in ion transport. Transepithelial fluid transport was measured in normal and cystic fibrosis cells. At rest, both types of cells showed an amiloride-sensitive fluid absorption that was inhibited by interferon-? but not by tumor necrosis factor-?. Our results show that interferon-? alters the transepithelial ion transport of cultured bronchial cells. This effect may change the ion composition and/or volume of periciliary fluid.