Apical SK potassium channels and Ca2+‐dependent anion secretion in endometrial epithelial cells

Palmer, Melissa; Schiller, Katherine R.; O’Grady, Scott M.

doi:10.1113/jphysiol.2007.142877

Cited by 17 publications

(17 citation statements)

References 39 publications

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“…1) indicating an absolute requirement for activation of a basolateral K ϩ channels to promote the transient secretory response observed. Luminal oviduct K ϩ is normally higher than plasma thus an active K ϩ secretory mechanism is likely to exist as has been shown in the uterus (34). Here we show that apical K ϩ channel inhibition reduced basal and ATP e -activated current most likely due to depolarization of the apical cell membrane resulting in a reduced driving force for anion secretion and thus reduced secretory current.…”

Section: Discussionsupporting

confidence: 67%

“…Over ten years ago the presence of a large conductance maxi-K ϩ channel type in the apical membranes of rabbit oviduct was reported (23). More recently the presence of calcium-activated potassium channels in the apical membrane of porcine endometrial epithelia, cells closely related to the oviduct, has been reported (34). In the majority of polarized epithelia, two principle types of basolateral K ϩ conductances have been described, activated by either an increase in cAMP or intracellular calcium providing an electrical driving force for chloride secretion (5,6,30).…”

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confidence: 99%

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Small conductance potassium channels drive ATP-activated chloride secretion in the oviduct

Keating

Quinlan

2012

American Journal of Physiology-Cell Physiology

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Keating N, Quinlan LR. Small conductance potassium channels drive ATP-activated chloride secretion in the oviduct. Am J Physiol Cell Physiol 302: C100 -C109, 2012. First published September 14, 2011; doi:10.1152/ajpcell.00503.2010.-The molecular mechanisms controlling fluid secretion within the oviduct have yet to be determined. As in other epithelia, both secretory and absorptive pathways are likely to work in tandem to drive appropriate ionic movement to support fluid movement across the oviduct epithelium. This study explored the role of potassium channels in basolateral extracellular ATP (ATP e)-stimulated ion transport in bovine oviduct epithelium using the Ussing chamber short-circuit current (I SC) technique. Basal I SC in bovine oviduct epithelium comprises both chloride secretion and sodium absorption and was inhibited by treatment with basolateral K ϩ channel inhibitors tetrapentlyammonium chloride (TPeA) or BaCl 2. Similarly, ATP-stimulated chloride secretion was significantly attenuated by pretreatment with BaCl 2, tetraethylammonium (TEA), tolbutamide, and TPeA. Basolateral K ϩ current, isolated using nystatin-perforation technique, was rapidly activated by ATP e, and pretreatment of monolayers with thapsigargin or TPeA abolished this ATP-stimulated K ϩ current. To further investigate the type of K ϩ channel involved in the ATP response in the bovine oviduct, a number of specific Ca 2ϩ -activated K ϩ channel inhibitors were tested on the ATP-induced ⌬I SC in intact monolayers. Charbydotoxin, (high conductance and intermediate conductance inhibitor), or paxilline, (high conductance inhibitor) did not significantly alter the ATP e response. However, pretreatment with the small conductance inhibitor apamin resulted in a 60% reduction in the response to ATP e. The presence of small conductance family member KCNN3 was confirmed by RT-PCR and immunohistochemistry. Measurements of intracellular calcium using Fura-2 spectrofluorescence imaging revealed the ability of ATP e to increase intracellular calcium in a phospholipase C-inositol 1,4,5-trisphosphate pathway-sensitive manner. In conclusion, these results provide strong evidence that purinergic activation of a calciumdependent, apamin-sensitive potassium conductance is essential to promote chloride secretion and thus fluid formation in the oviduct. oviduct epithelium; apamin; fertilization THE FLUID formed within the oviduct provides an essential and appropriate environment for gamete maturation, transport, fertilization, and early embryo development. Although the composition of this fluid has been well documented for some time (8,40), the mechanisms underlying fluid formation surprisingly remain poorly understood.As a general principle, fluid formation is secondary to and driven by the active transport of ions across an epithelial layer.

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Section: Discussionsupporting

confidence: 67%

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confidence: 99%

Small conductance potassium channels drive ATP-activated chloride secretion in the oviduct

Keating

Quinlan

2012

American Journal of Physiology-Cell Physiology

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“…Apamin-sensitive SK channels are activated by 17β-estradiol (E2) in gonadotropin-releasing hormone (GnRH) neurons [9]. Estrogen elevates the SK3 mRNA expression in the rostral basal hypothalamus [10], endometrial epithelial cells [11], and myometrial cells [12]. Furthermore, the overexpression of SK3 channels dampens uterine contractility [13].…”

Section: Introductionmentioning

confidence: 99%

Estrogen Regulates the Expression of Small-Conductance Ca2+-Activated K+ Channels in Colonic Smooth Muscle Cells

et al. 2015

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Aim: This study aimed to determine the effects of small-conductance Ca²⁺-activated K⁺ (SK) channels in colonic relaxation and the regulation of SK channels by estrogen. Methods: The contractile activity of muscle strips from male rats was estimated, and drugs including vehicle (DMSO), 17β-estradiol (E2), or apamin (SK blocker) were added, respectively. In a further experiment, muscle strips were preincubated with apamin before exposure to E2. The levels of the SK2 and SK3 protein expression in the colonic smooth muscle cells (SMCs) were detected. SMCs were treated with ICI 182780 (estrogen receptor [ER] antagonist) plus E2, BSA-E2, PPT (ERα agonist), or DPN (ERβ agonist). SK3 mRNA and protein expression levels were detected. Results: The muscle strips responded to E2 with a decrease and to apamin with a transient increase in tension. Preincubation with apamin partially prevented E2-induced relaxation. Two SK channel subtypes, SK2 and SK3, were coexpressed with α-actin in colonic SMCs. The quantitative ratio of the SK transcriptional expression in colonic SMCs was SK3 > SK2. The SK3 expression was upregulated by E2, and was downregulated by ICI 182780, but was not influenced by BSA-E2. Furthermore, the effect of PPT on the expression of SK3 was almost the same as that of E2, while DPN did not influence the protein expression of SK3. Conclusion: These findings indicate that SK3 is involved in the E2-induced relaxing effect on rat colonic smooth muscle. Furthermore, E2 upregulates the expression of SK3 in rat SMCs, and that this effect is mediated via the ERα receptor.

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“…In previous studies, the immortalized porcine glandular endometrial epithelial cell culture (PEG) was characterized and represented as the normal cell culture for examining the effects of Ge and Di on the epithelial function (Palmer et al 2008, Deachapunya & Poonyachoti 2013. Thus, in this study, we aimed to investigate whether the soy isoflavones, Ge or Di, alter the endometrial barrier function in the PEG cells as determined by TER and FITC-dextran flux (FD-4).…”

Section: Introductionmentioning

confidence: 99%

Soy isoflavones improves endometrial barrier through tight junction gene expression

Kiatprasert¹,

Deachapunya²,

Benjanirat³

et al. 2015

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Contamination with bacterial endotoxin causes the disruption of the tight junction (TJ) barrier. We investigated the ameliorative effect of dietary flavonoids genistein (Ge) and daidzein (Di) in normal or lipopolysaccharide (LPS)-induced disruption of epithelial barrier function of the endometrium. Using the immortalized porcine glandular endometrial epithelial cells (PEG), transepithelial electrical resistance (TER) and FITC-dextran flux (FD-4) across the monolayer were measured. The mRNA expression of TJ proteins, zona occludens-1 (ZO1), and claudin-1, -3, -4, -7 and -8 was evaluated by real-time RT-PCR for coinciding effect of Ge or Di occurred at the gene transcription level. The results revealed that Ge and Di altered the TER, depending on times and concentrations. Low concentration (10 K10 M) of both compounds decreased the TER, whereas higher concentrations (10 K8 and 10 K6 M) increased the TER which was not related to the FD-4 flux. The increased TER by Ge or Di was parallel to the induction of claudin-3 and -4 or -8 mRNA expression respectively. With LPS inoculation, all isoflavone treatments inhibited the decreased TER induced by LPS, but only Ge (10 K8 or 10 K6 M) or Di (10 K10 or 10 K6 M) was coincidence with the decreased FD-4 flux. Under this LPS-stimulated condition, some or all examined TJ gene expressions appeared to be promoted by specific concentration of Ge or Di respectively. Our findings suggest that the soy isoflavones treatment could promote and restore the impaired endometrial barrier function caused by LPS contamination.

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Apical SK potassium channels and Ca²⁺‐dependent anion secretion in endometrial epithelial cells

Cited by 17 publications

References 39 publications

Small conductance potassium channels drive ATP-activated chloride secretion in the oviduct

Small conductance potassium channels drive ATP-activated chloride secretion in the oviduct

Estrogen Regulates the Expression of Small-Conductance Ca<sup>2+</sup>-Activated K<sup>+</sup> Channels in Colonic Smooth Muscle Cells

Soy isoflavones improves endometrial barrier through tight junction gene expression

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