Ibuprofen inhibits cystic fibrosis transmembrane conductance regulator-mediated Cl- secretion.
We evaluated the acute effects of ibuprofen and salicylic acid on cAMP-mediated Cl- secretion (Isc) in both colonic and airway epithelia. In T84 cells, ibuprofen inhibited the forskolin-dependent Isc in a concentration-dependent manner, having an apparent Ki of 142 microM. Salicylic acid inhibited Isc with an apparent Ki of 646 microM. We determined whether ibuprofen would also inhibit the forskolin-stimulated Isc in primary cultures of mouse trachea epithelia (MTE) and human bronchial epithelia (HBE). Similar to our results in T84 cells, ibuprofen (500 microM) inhibited the forskolin-induced Isc in MTEs and HBEs by 59+/-4% (n = 11) and 39+/-6% (n = 8), respectively. Nystatin was employed to selectively permeabilize the basolateral or apical membrane to determine the effect of ibuprofen on apical Cl- (ICl) and basolateral K+ (IK) currents after stimulation by forskolin. After forskolin stimulation, ibuprofen (500 microM) reduced both the ICl and IK; reducing ICl and IK by 60 and 15%, respectively. To determine whether this inhibition of ICl was due to the inhibition of CFTR, the effects of ibuprofen and salicylic acid on CFTR Cl- channels in excised, inside-out patches from L-cells were evaluated. Ibuprofen (300 microM) reduced CFTR Cl- current by 60+/-16% and this was explained by a short-lived block (approximately 1.2 ms) which causes an apparent reduction in single channel amplitude from 1.07+/-0.04 pA to 0.59+/-0.04 pA (n = 3). Similarly, salicylic acid (3 mM) reduced CFTR Cl- current by 50+/-8% with an apparent reduction in single channel amplitude from 1.08+/-0.03 pA to 0.48+/-0.06 pA (n = 4). Based on these results, we conclude that the NSAIDs ibuprofen and salicylic acid inhibit cAMP-mediated Cl- secretion in human colonic and airway epithelia via a direct inhibition of CFTR Cl- channels as well as basolateral membrane K+ channels. This may reduce their efficacy in conjunction with other therapeutic strategies designed to increase CFTR expression and/or function in secretory epithelia.
Devor
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Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA. dd2+@pitt.edu
Schultz
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D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D001980:Bronchi / Q000166:cytology / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism*; D003106:Colon / Q000166:cytology / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000187:drug effects*; D004553:Electric Conductivity; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007052:Ibuprofen / Q000494:pharmacology*; D051379:Mice; D011188:Potassium / Q000378:metabolism; D012459:Salicylates / Q000494:pharmacology; D020156:Salicylic Acid; D014132:Trachea / Q000166:cytology / Q000187:drug effects
D000894:Anti-Inflammatory Agents, Non-Steroidal; C505032:CFTR protein, human; D002712:Chlorides; D012459:Salicylates; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000242:Cyclic AMP; D020156:Salicylic Acid; D011188:Potassium; D007052:Ibuprofen