[HTML][HTML] Inhibition of cAMP-activated intestinal chloride secretion by diclofenac: cellular mechanism and potential application in cholera
P Pongkorpsakol… - PLoS neglected …, 2014 - journals.plos.org
P Pongkorpsakol, N Pathomthongtaweechai, P Srimanote, S Soodvilai, V Chatsudthipong…
PLoS neglected tropical diseases, 2014•journals.plos.orgCyclic AMP-activated intestinal Cl− secretion plays an important role in pathogenesis of
cholera. This study aimed to investigate the effect of diclofenac on cAMP-activated Cl−
secretion, its underlying mechanisms, and possible application in the treatment of cholera.
Diclofenac inhibited cAMP-activated Cl− secretion in human intestinal epithelial (T84) cells
with IC50 of∼ 20 µM. The effect required no cytochrome P450 enzyme-mediated metabolic
activation. Interestingly, exposures of T84 cell monolayers to diclofenac, either in apical or …
cholera. This study aimed to investigate the effect of diclofenac on cAMP-activated Cl−
secretion, its underlying mechanisms, and possible application in the treatment of cholera.
Diclofenac inhibited cAMP-activated Cl− secretion in human intestinal epithelial (T84) cells
with IC50 of∼ 20 µM. The effect required no cytochrome P450 enzyme-mediated metabolic
activation. Interestingly, exposures of T84 cell monolayers to diclofenac, either in apical or …
Cyclic AMP-activated intestinal Cl− secretion plays an important role in pathogenesis of cholera. This study aimed to investigate the effect of diclofenac on cAMP-activated Cl− secretion, its underlying mechanisms, and possible application in the treatment of cholera. Diclofenac inhibited cAMP-activated Cl− secretion in human intestinal epithelial (T84) cells with IC50 of ∼20 µM. The effect required no cytochrome P450 enzyme-mediated metabolic activation. Interestingly, exposures of T84 cell monolayers to diclofenac, either in apical or basolateral solutions, produced similar degree of inhibitions. Analyses of the apical Cl− current showed that diclofenac reversibly inhibited CFTR Cl− channel activity (IC50∼10 µM) via mechanisms not involving either changes in intracellular cAMP levels or CFTR channel inactivation by AMP-activated protein kinase and protein phosphatase. Of interest, diclofenac had no effect on Na+-K+ ATPases and Na+-K+-Cl− cotransporters, but inhibited cAMP-activated basolateral K+ channels with IC50 of ∼3 µM. In addition, diclofenac suppressed Ca2+-activated Cl− channels, inwardly rectifying Cl− channels, and Ca2+-activated basolateral K+ channels. Furthermore, diclofenac (up to 200 µM; 24 h of treatment) had no effect on cell viability and barrier function in T84 cells. Importantly, cholera toxin (CT)-induced Cl− secretion across T84 cell monolayers was effectively suppressed by diclofenac. Intraperitoneal administration of diclofenac (30 mg/kg) reduced both CT and Vibrio cholerae-induced intestinal fluid secretion by ∼70% without affecting intestinal fluid absorption in mice. Collectively, our results indicate that diclofenac inhibits both cAMP-activated and Ca2+-activated Cl− secretion by inhibiting both apical Cl− channels and basolateral K+ channels in intestinal epithelial cells. Diclofenac may be useful in the treatment of cholera and other types of secretory diarrheas resulting from intestinal hypersecretion of Cl−.
PLOS