ClC-2 Cl- channels in human lung epithelia: activation by arachidonic acid, amidation, and acid-activated omeprazole.
ClC-2 Cl- channels represent a potential target for therapy in cystic fibrosis. Key questions regarding the feasibility of using ClC-2 as a therapeutic target are addressed in the present studies, including whether the channels are present in human lung epithelia and whether activators of the channel can be identified. Two new mechanisms of activation of human recombinant ClC-2 Cl- channels expressed in HEK-293 cells were identified: amidation with glycine methyl ester catalyzed by 1-ethyl-3(3-dimethylaminopropyl) carbodiimide (EDC) and treatment with acid-activated omeprazole. ClC-2 mRNA was detected by RT-PCR. Channel function was assessed by measuring Cl- currents by patch clamp in the presence of a cAMP-dependent protein kinase (PKA) inhibitor, myristoylated protein kinase inhibitor, to prevent PKA-activated Cl- currents. Calu-3, A549, and BEAS-2B cell lines derived from different human lung epithelia contained ClC-2 mRNA, and Cl- currents were increased by amidation, acid-activated omeprazole, and arachidonic acid. Similar results were obtained with buccal cells from healthy individuals and cystic fibrosis patients. The ClC-2 Cl- channel is thus a potential target for therapy in cystic fibrosis.
Cuppoletti
J
J
Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0576, USA. John.Cuppoletti@uc.edu
Tewari
K P
KP
Sherry
A M
AM
Kupert
E Y
EY
Malinowska
D H
DH
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000577:Amides / Q000378:metabolism; D001095:Arachidonic Acids / Q000494:pharmacology*; D000090007:CLC-2 Chloride Channels; D002460:Cell Line; D002478:Cells, Cultured; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D003550:Cystic Fibrosis / Q000188:drug therapy / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000494:pharmacology; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D009061:Mouth Mucosa / Q000166:cytology; D009853:Omeprazole / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000378:metabolism
D000577:Amides; D001095:Arachidonic Acids; C505032:CFTR protein, human; D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D002712:Chlorides; D004791:Enzyme Inhibitors; D010726:Phosphodiesterase Inhibitors; D011994:Recombinant Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D005576:Colforsin; D000255:Adenosine Triphosphate; D008274:Magnesium; D009853:Omeprazole; D005022:Ethyldimethylaminopropyl Carbodiimide; D015056:1-Methyl-3-isobutylxanthine