EGF mediates calcium-activated chloride channel activation in the human bronchial epithelial cell line 16HBE14o-: involvement of tyrosine kinase p60c-src.
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.
Jeulin
Claudette
C
Laboratoire de Cytophysiologie et Toxicologie Cellulaire, case courrier 7073, 3ème étage, T53-54, Université Paris 7 Denis Diderot, 2 Place Jussieu, 75251 Paris Cedex 05, France. claudette.jeulin@univ-paris-diderot.fr
Seltzer
Virginie
V
Bailbé
Danielle
D
Andreau
Karine
K
Marano
Francelyne
F
D000255:Adenosine Triphosphate / Q000378:metabolism; D001980:Bronchi / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002460:Cell Line; D018118:Chloride Channels / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000378:metabolism* / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D018408:Patch-Clamp Techniques; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000378:metabolism*; D011799:Quinazolines; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020032:Tyrphostins / Q000494:pharmacology
C492109:CLCA1 protein, human; D018118:Chloride Channels; D011799:Quinazolines; D011994:Recombinant Proteins; D020032:Tyrphostins; C101044:RTKI cpd; D004815:Epidermal Growth Factor; D000255:Adenosine Triphosphate; D066246:ErbB Receptors; D016392:Proto-Oncogene Proteins pp60(c-src)