Regulation of chloride secretion across porcine endometrial epithelial cells by prostaglandin E₂

Abstract

The objective of this study was to investigate the mechanism of PGE2 regulation of Cl− transport across glandular endometrial cells grown in primary culture. Most of the basal short circuit current (Isc) was inhibited by luminal addition of 5‐nitro‐2‐(3‐phenylpropylamino)benzoic acid (NPPB) or glibenclamide, suggesting the presence of a basally active Cl− conductance in the apical membrane. Basolateral addition of 10 μM PGE2 increased Isc by 41 ± 3 μA. A similar response was observed when cells were treated with 8‐(4‐chlorophenylthio) adenosine 3′,5′‐cyclic monophosphate (CPT‐cAMP). Pretreatment of monolayers with NPPB and glibenclamide blocked the PGE2 and cAMP‐mediated increase in Isc, suggesting that the effects of PGE2 and cAMP were dependent on the activity of an apical NPPB‐ and glibenclamide‐sensitive conductance. Addition of 50 nM antiPGE2 antibody to the basolateral bathing solution decreased basal Isc by 20 % and shifted the threshold response to exogenous PGE2. This result suggests autocrine regulation of electrogenic Cl− transport by PGE2. Experiments with amphotericin B‐permeabilized monolayers revealed that the apical PGE2‐activated, NPPB‐ and glibenclamide‐sensitive conductance was Cl− dependent and that the current‐voltage relationship and anion permeation properties (SCN−>Br− > Cl− > I−) were characteristic of the cystic fibrosis transmembrane conductance regulator (CFTR). Cultured porcine endometrial epithelial cells were specifically labelled with an antibody to a peptide sequence within the regulatory domain of CFTR. The effect of PGE2 was blocked by basolateral addition of bumetanide and furosemide at concentrations that are selective for inhibition of Na+‐K+‐2Cl−cotransport activity. The effect of bumetanide on Isc was Cl− dependent, suggesting a role for the bumetanide‐sensitive transport pathway in Cl− secretion. PGE2 and cAMP also activated an outwardly rectifying basolateral K+ channel which presumably sustains the driving force for electrogenic Cl− efflux across the apical membrane. The concentration‐conductance and concentration‐Isc response relationships for PGE2 showed that basolateral K+ permeability was rate limiting with respect to transepithelial anion secretion and that activation of a basolateral K+ channel by PGE2 was necessary to achieve maximum rates of Cl− secretion.

Sodium and anion transport across the avian uterine (shell gland)epithelium

“…Although this result appears to be consistent with the suggested model above it is important to note that DIDS also blocks certain types of Cl -channels, thus more direct methods will be required to establish the mechanism of HCO 3 -secretion in this epithelium. Stimulation of Cl -secretion by 8-cpt cAMP was previously reported in cultured mammalian endometrial epithelial cells (Deachapunya and O'Grady, 1998). However, native porcine endometrial tissues mounted in Ussing chambers and treated with 8-cpt cAMP or with PGF2α, produced a sustained increase in amiloride-sensitive Na + absorption (Vetter and O'Grady, 1996;Vetter et al, 1997).…”

Fluid Secretion Caused by Aerolysin-Like Hemolysin of Aeromonas sobria in the Intestines Is Due to Stimulation of Production of Prostaglandin E 2 via Cyclooxygenase 2 by Intestinal Cells

“…5). Deachapunya and O'Grady suggested that PGE 2 activates adenylyl cyclase in cultured endometrial epithelial cells, resulting in an increase in intracellular cAMP (11). Other reports showed that there are four PGE 2 receptors (EPs), designated EP1, EP2, EP3, and EP4, and that PGE 2 stimulates the production of cAMP via EP2 and EP4 receptors linked to the Gs protein (4,31).…”

“…It is well established that the intracellular cAMP activates CFTR Cl Ϫ channels through protein phosphorylation mediated by PKA (11). We previously found that hemolysin activates the cAMP-dependent Cl Ϫ secretory pathway, which is related to CFTR, in Caco-2 cells (a human colonic epithelial cell line) (39).…”

Prostaglandin E2 Produced by Entamoeba histolytica Signals via EP4 Receptor and Alters Claudin-4 to Increase Ion Permeability of Tight Junctions

“…20 To maintain charge balance in the lumen, sodium ions (cations) are pulled across the epithelium, also drawing water molecules and thus causing diarrhea. 19 PGE 2 is a potent colonic epithelial chloride ion secretagogue [21][22][23] ; however, it is not known whether it induces sodium ion flux across the epithelium. Colonic epithelial tight junctions (TJs) act as an important barrier for paracellular movement of macromolecules and ions across the epithelium.…”