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Title

Defective regulation of gap junctional coupling in cystic fibrosis pancreatic duct cells

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Published in Journal of Clinical Investigation. 1999, vol. 103, no. 12, p. 1677-84
Abstract The cystic fibrosis (CF) gene encodes a cAMP-gated Cl- channel (cystic fibrosis transmembrane conductance regulator [CFTR]) that mediates fluid transport across the luminal surfaces of a variety of epithelial cells. We have previously shown that gap junctional communication and Cl- secretion were concurrently regulated by cAMP in cells expressing CFTR. To determine whether intercellular communication and CFTR-dependent secretion are related, we have compared gap junctional coupling in a human pancreatic cell line harboring the DeltaF508 mutation in CFTR and in the same cell line in which the defect was corrected by transfection with wild-type CFTR. Both cell lines expressed connexin45 (Cx45), as evidenced by RT-PCR, immunocytochemistry, and dual patch-clamp recording. Exposure to agents that elevate intracellular cAMP or specifically activate protein kinase A evoked Cl- currents and markedly increased junctional conductance of CFTR-expressing pairs, but not in the parental cells. The latter effect, which was caused by an increase in single-channel activity but not in unitary conductance of Cx45 channels, was not prevented by exposing CFTR-expressing cells to a Cl- channel blocker. We conclude that expression of functional CFTR restored the cAMP-dependent regulation of junctional conductance in CF cells. Direct intercellular communication coordinates multicellular activity in tissues that are major targets of CF manifestations. Consequently, defective regulation of gap junction channels may contribute to the altered functions of tissues affected in CF.
Keywords Cell Communication/drug effects/genetics/physiologyChloride Channels/metabolismCyclic AMP/pharmacologyCystic Fibrosis/metabolism/pathologyCystic Fibrosis Transmembrane Conductance Regulator/biosynthesis/genetics/physiologyGap Junctions/drug effects/pathology/physiologyHumansPancreatic Ducts/drug effects/pathology/physiologyPatch-Clamp TechniquesRNA, Messenger/biosynthesisTumor Cells, Cultured
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PMID: 10377174
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Article (Published version) (252 Kb) - document accessible for UNIGE members only Limited access to UNIGE
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Research group Mucoviscidose et jonctions GAP (229)
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CHANSON, Marc, SCERRI, Isabelle, SUTER, Susanne. Defective regulation of gap junctional coupling in cystic fibrosis pancreatic duct cells. In: Journal of Clinical Investigation, 1999, vol. 103, n° 12, p. 1677-84. doi: 10.1172/JCI5645 https://archive-ouverte.unige.ch/unige:27029

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Deposited on : 2013-03-26

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