EGF mediates calcium-activated chloride channel activation in the human bronchial epithelial cell line 16HBE14o-: involvement of tyrosine kinase p60c-src.
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Jeulin C, Seltzer V, Bailbe D, Andreau K, Marano F
EGF mediates calcium-activated chloride channel activation in the human bronchial epithelial cell line 16HBE14o-: involvement of tyrosine kinase p60c-src.
Am J Physiol Lung Cell Mol Physiol. 2008 Sep;295(3):L489-96. doi: 10.1152/ajplung.90282.2008. Epub 2008 Jun 27.
- PubMed ID
- 18586953 [ View in PubMed]
- Abstract
Particulate atmospheric pollutants interact with the human airway epithelium, which releases cytokines, chemokines, and EGF receptor (EGFR) ligands leading to proinflammatory responses. There is little information concerning the short-term effects of EGFR activation by extracellular ligands on ionic regulation of airway surface lining fluids. We identified in the membrane of human epithelial bronchial cells (16HBE14o(-) line) an endogenous calcium- and voltage-dependent, outwardly rectifying small-conductance chloride channel (CACC), and we examined the effects of EGF on CACC activity. Ion channel currents were recorded with the patch-clamp technique. In cell-attached membrane patches, CACC were activated by exposure of the external surface of the cells to physiological concentrations of EGF without any change in cytosolic Ca(2+) concentration ([Ca(2+)](i)) and inhibited by tyrphostin AG-1478 (an inhibitor of EGFR that also blocks EGF-dependent Src family kinase activation). EGF activation of c-Src protein in 16HBE14o(-) cells was observed, and the signaling pathway elicited by EGFR was blocked by tyrphostin AG-1478. In excised inside-out membrane patches CACC were activated by exposure of the cytoplasmic face of the channels to the human recombinant Src(p60(c-src)) kinase with endogenous or exogenous ATP and inhibited by lambda-protein phosphatase. Secretion of EGFR ligands by epithelial airway cells exposed to pollutants would then elicit a rapid and direct ionic response of CACC mediated by EGFR activation via a Src kinase family-dependent signaling pathway.