Estrogen Acidifies Vaginal pH by Up-Regulation of Proton Secretion via the Apical Membrane of Vaginal-Ectocervical Epithelial Cells

Abstract The objective of this study was to assess estrogen-dependent cellular mechanisms that could contribute to the acid pH of the vaginal lumen. Cultures of normal human cervical-vaginal epithelial (hECE) cells and endocervical cells were grown on filters, and acidification of the extracellular solutions on the luminal (L-pHo) and contraluminal (CL-pHo) sides was measured. The hECE cells and endocervical cells decreased CL-pHo from 7.40 to 7.25 within 20–30 min of incubation in basic salt solution. Endocervical cells also produced a similar decrease in L-pHo. In contrast, hECE cells acidified L-pHo down to pH 7.05 when grown as monoculture and down to pH 6.05 when grown in coculture with human cervical fibroblasts. This enhanced acid secretion into the luminal compartment was estrogen dependent because removal of endogenous steroid hormones attenuated the effect, whereas treatment with 17β-estradiol restored it. The 17β-estradiol effect was dose dependent (EC50 0.5 nm) and could be mimicked by diethylstilbestrol and in part by estrone and tamoxifen. Preincubation with ICI-182780, but not with progesterone, blocked the estrogen effect. Preincubation of cells with the V-ATPase blocker bafilomycin A1, when administered to the luminal solution, attenuated the baseline and estrogen-dependent acid secretion into the luminal solution. Treatment with EGTA, to abrogate the tight junctional resistance, blocked the decrease in L-pHo and stimulated a decrease in CL-pHo, indicating that the tight junctions are necessary for maintaining luminal acidification. We conclude that vaginal-ectocervical cells acidify the luminal canal by a mechanism of active proton secretion, driven in part by V-H+-ATPase located in the apical plasma membrane and that the baseline active net proton secretion occurs constitutively throughout life and that this acidification is up-regulated by estrogen.

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Expression and distribution of the Na+- HCO 3 − cotransporter in human pancreas

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1999.277.2.g487 ◽

1999 ◽

Vol 277 (2) ◽

pp. G487-G494 ◽

Cited By ~ 32

Author(s):

Christopher R. Marino ◽

Virginia Jeanes ◽

Walter F. Boron ◽

Bernhard M. Schmitt

Keyword(s):

Northern Blot ◽

Islet Cells ◽

Rat Kidney ◽

Physiological Role ◽

Human Pancreas ◽

Transmembrane Conductance Regulator ◽

Transmembrane Conductance ◽

Cellular Mechanisms ◽

Double Labeling ◽

Normal Human

The cellular mechanisms of [Formula: see text] secretion in the human pancreas are unclear. Expression of a Na+-[Formula: see text]cotransporter (NBC) mRNA has been observed recently, but the distribution and physiological role of the NBC protein are not known. Here we examined the expression and localization of NBC in human pancreas by Northern blot, immunoblot, and immunofluorescence microscopy. Rat kidney NBC probes detected a single 9.5-kb band by Northern blot. On immunoblots, two polyclonal antisera directed against different epitopes of rat kidney NBC identified a single ∼130-kDa protein. In cryosections of normal human pancreas, both antisera labeled basolateral membranes of large, morphologically identifiable ducts and produced a distinct labeling pattern in the remainder of the parenchyma. In double-labeling experiments, NBC immunoreactivity in the parenchyma colocalized with the Na+-K+pump, a basolateral marker. In contrast, NBC and cystic fibrosis transmembrane conductance regulator, an apical membrane marker, were detected within the same histological structures but at different subcellular localizations. The NBC antisera did not label acinar or islet cells. Our observations suggest that secretion of[Formula: see text] by human pancreatic duct cells involves the basolateral uptake of Na+and[Formula: see text] via NBC, an electrogenic Na+-[Formula: see text]cotransporter.

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ME-3407, a new antiulcer agent, inhibits acid secretion by interfering with redistribution of H(+)-K(+)-ATPase

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1997.272.5.g1122 ◽

1997 ◽

Vol 272 (5) ◽

pp. G1122-G1134 ◽

Cited By ~ 8

Author(s):

T. Urushidani ◽

Y. Muto ◽

T. Nagao ◽

X. Yao ◽

J. G. Forte

Keyword(s):

Acid Secretion ◽

Proton Pump ◽

Cell Activation ◽

Second Messengers ◽

Apical Plasma Membrane ◽

Peptic Ulcers ◽

Gastric Glands ◽

Antiulcer Agent ◽

Potent Inhibition ◽

Apical Membranes

ME-3407 is a newly developed antiulcer drug that markedly promoted the healing of acetic acid-induced chronic ulcers in rats presumably due to potent inhibition of acid secretion. ME-3407 and its metabolites, the sulfoxide of which was preserved, produced dosedependent inhibition of aminopyrine accumulation by rabbit gastric glands stimulated by any agonist, suggesting that the site of their action was downstream from the production of second messengers. Although one of the metabolites, EF-4025, showed some inhibitory effects on functional activities of H(+)-K(+)-ATPase, ME-3407 itself was not a proton pump inhibitor. ME-3407, but not omeprazole, inhibited the stimulation-associated redistribution of H(+)-K(+)-ATPase from microsomes into the apical membranes in addition to delocalizing ezrin, a putative F-actin-membrane linker, from apical plasma membrane. ME-3407 and EF-4025 inhibited myosin light chain kinase (MLCK) and protein kinase A activities. Because another MLCK inhibitor, wortmannin, showed the same properties as ME-3407, i.e., inhibition of aminopyrine accumulation, inhibition of stimulation-associated redistribution of H(+)-K(+)-ATPase, and abnormal distribution of ezrin, we hypothesize that MLCK is one of the potential targets for the drug. We conclude that ME-3407 is a promising drug for treating peptic ulcers, as well as a useful tool for studying mechanisms of parietal cell activation, especially related to the recruitment and recycling of the proton pump.

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Heterogeneity of uroplakin localization in human normal urothelium, papilloma and papillary carcinoma

Radiology and Oncology ◽

10.2478/raon-2013-0052 ◽

2013 ◽

Vol 47 (4) ◽

pp. 338-345 ◽

Cited By ~ 11

Author(s):

Dasa Zupancic ◽

Rok Romih

Keyword(s):

Papillary Carcinoma ◽

Recurrence Rate ◽

Ultrastructural Localization ◽

Ultrastructural Level ◽

Apical Plasma Membrane ◽

High Recurrence Rate ◽

Tumour Resection ◽

Urothelial Cells ◽

Normal Human ◽

Normal Urothelium

Abstract Background. Uroplakins are differentiation-related membrane proteins of urothelium. We compared uroplakin expression and ultrastructural localization in human normal urothelium, papilloma and papillary carcinoma. Because of high recurrence rate of these tumours, treated by transurethral resection, we investigated urothelial tumour, resection border and uninvolved urothelium. Patients and methods. Urinary bladder samples were obtained from tumour free control subjects and patients with papilloma and papillary carcinoma. Immunohistochemical and immunoelectron labelling of uroplakins were performed. Results. In normal human urothelium with continuous uroplakin-positive superficial cell layer uroplakins were localized to flattened mature fusiform vesicles and apical plasma membrane of umbrella cells. Diverse uroplakin expression was found in papilloma and papillary carcinoma. Three aberrant differentiation stages of urothelial cells, not found in normal urothelium, were recognized in tumours. Diverse uroplakin expression and aberrant differentiation were occasionally found in resection border and in uninvolved urothelium. Conclusions. We demonstrated here that uroplakin expression and localization in urothelial tumours is altered when compared to normal urothelium. In patients with papilloma and papillary carcinoma immunolabelling of uroplakins at ultrastructural level shows aberrant urothelial differentiation. It is possible that aberrant differentiation stages of urothelial cells in resection border and in uninvolved urothelium contribute to high recurrence rate.

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Cellular mechanisms and inhibitors of gastric acid secretion

Drugs of Today ◽

10.1358/dot.1999.35.10.561693 ◽

1999 ◽

Vol 35 (10) ◽

pp. 743 ◽

Cited By ~ 5

Author(s):

M.J.-M. Lewin

Keyword(s):

Acid Secretion ◽

Gastric Acid Secretion ◽

Gastric Acid ◽

Cellular Mechanisms

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Cellular mechanisms of acid secretion in the posterior midgut of the larval mosquito (Aedes aegypti)

Journal of Experimental Biology ◽

10.1242/jeb.037549 ◽

2009 ◽

Vol 213 (2) ◽

pp. 295-300 ◽

Cited By ~ 14

Author(s):

U. Jagadeshwaran ◽

H. Onken ◽

M. Hardy ◽

S. B. Moffett ◽

D. F. Moffett

Keyword(s):

Aedes Aegypti ◽

Acid Secretion ◽

Cellular Mechanisms ◽

Posterior Midgut

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17β-Estradiol attenuates p38MAPK activity but not PKCα induced by angiotensin II in the brain

Journal of Endocrinology ◽

10.1530/joe-18-0095 ◽

2019 ◽

Vol 240 (2) ◽

pp. 345-360 ◽

Cited By ~ 2

Author(s):

G Almeida-Pereira ◽

T Vilhena-Franco ◽

R Coletti ◽

S Q Cognuck ◽

H V P Silva ◽

...

Keyword(s):

Angiotensin Ii ◽

P38 Mapk ◽

Mapk Pathway ◽

Sodium Intake ◽

Physiological Role ◽

Renin Angiotensin System ◽

Mapk Signaling ◽

Cellular Mechanisms ◽

Ovx Rats ◽

17Β Estradiol

17β-Estradiol (E2) has been shown to modulate the renin–angiotensin system in hydromineral and blood pressure homeostasis mainly by attenuating angiotensin II (ANGII) actions. However, the cellular mechanisms of the interaction between E2 and angiotensin II (ANGII) and its physiological role are largely unknown. The present experiments were performed to better understand the interaction between ANGII and E2 in body fluid control in female ovariectomized (OVX) rats. The present results are the first to demonstrate that PKC/p38 MAPK signaling is involved in ANGII-induced water and sodium intake and oxytocin (OT) secretion in OVX rats. In addition, previous data from our group revealed that the ANGII-induced vasopressin (AVP) secretion requires ERK1/2 signaling. Therefore, taken together, the present observations support a novel concept that distinct intracellular ANGII signaling gives rise to distinct neurohypophyseal hormone release. Furthermore, the results show that E2 attenuates p38 MAPK phosphorylation in response to ANGII but not PKC activity in the hypothalamus and the lamina terminalis, suggesting that E2 modulates ANGII effects through the attenuation of the MAPK pathway. In conclusion, this work contributes to the further understanding of the interaction between E2 and ANGII signaling in hydromineral homeostasis, as well as it contributes to further elucidate the physiological relevance of PKC/p38 MAPK signaling on the fluid intake and neurohypophyseal release induced by ANGII.

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The gastric H, K-ATPase system also functions as the Na, K-ATPase and Ca-ATPase in altered states

F1000Research ◽

10.12688/f1000research.2-165.v1 ◽

2013 ◽

Vol 2 ◽

pp. 165

Author(s):

Tushar Ray

Keyword(s):

Atpase Activity ◽

Acid Secretion ◽

Proton Pump ◽

Intracellular Signaling ◽

Parietal Cells ◽

Apical Plasma Membrane ◽

Altered States ◽

Apparent Lack ◽

Ca Pump ◽

Na Pump

This article offers an explanation for the apparent lack of Na, K-ATPase activity in parietal cells although ouabain has been known to inhibit gastric acid secretion since 1962. The gastric H, K-ATPase (proton-pump) seems to be acting in altered states, thus behaving like a Na, K-ATPase (Na-pump) and/or Ca-ATPase (Ca-pump) depending on cellular needs. This conclusion is based on the following findings. First, parietal cell fractions do not exhibit Na, K-ATPase activity at pH 7.0 but do at pH 8.5. Second, the apical plasma membrane (APM) fraction exhibits a (Ca or Mg)-ATPase activity with negligible H, K-ATPase activity. However, when assayed with Mg alone in presence of the 80 k Da cytosolic proton-pump activator (HAF), the APM fraction reveals remarkably high H, K-ATPase activity, suggesting the observed low affinity of Ca (or Mg)-ATPase is an altered state of the latter. Third, calcium (between 1 and 4 µM) shows both stimulation and inhibition of the HAF-stimulated H, K-ATPase depending on its concentration, revealing a close interaction between the proton-pump activator and local Ca concentration in gastric H, K-ATPase function. Such interactions suggest that Ca is acting as a terminal member of the intracellular signaling system for the HAF-regulated proton-pump. It appears that during resting state, the HAF-associated H, K-ATPase remains inhibited by Ca (>1 µM) and, prior to resumption of acid secretion the gastric H, K-ATPase acts temporarily as a Ca-pump for removing excess Ca from its immediate environment. This conclusion is consistent with the recent reports of immunochemical co-localization of the gastric H, K-ATPase and Ca-ATPase by superimposition in parietal cells, and a transitory efflux of Ca immediately preceding the onset of acid secretion. These new perspectives on proton-pump function would open new avenues for a fuller understanding of the intracellular regulation of the ubiquitous Na-pump.

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Stimulation of gastric acid secretion by cAMP in a novel alpha-toxin-permeabilized gland model

AJP Cell Physiology ◽

10.1152/ajpcell.1996.271.1.c61 ◽

1996 ◽

Vol 271 (1) ◽

pp. C61-C73 ◽

Cited By ~ 33

Author(s):

X. Yao ◽

S. M. Karam ◽

M. Ramilo ◽

Q. Rong ◽

A. Thibodeau ◽

...

Keyword(s):

Plasma Membrane ◽

Acid Secretion ◽

Gastric Acid Secretion ◽

Gastric Acid ◽

Cell Activation ◽

Gastric Gland ◽

Secretory Activity ◽

Apical Plasma Membrane ◽

Alpha Toxin ◽

Maximal Stimulation

It is generally believed that histamine-stimulated gastric acid secretion involves a transient elevation of intracellular Ca2+ and the adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA) cascade through phosphorylation, whose actions ultimately effect the fusion of H(+)-K(+)-adenosinetriphosphatase (ATPase)-containing vesicles to the apical plasma membrane of parietal cells. To dissect the signaling events underlying gastric acid secretion, we have developed a permeabilized gastric gland model using Staphylococcus alpha-toxin. The advantage of this model is its ability to retain cytosolic components that are required for the secretory machinery. Here we show that acid secretion in alpha-toxin-permeabilized glands is a cAMP-dependent process, reaching a maximal stimulation at 100 microM cAMP. The cAMP-elicited acid secretion, as monitored by the accumulation of the weak base aminopyrine (AP), required functional mitochondria or exogenously supplied ATP. Maximal stimulation elicited by cAMP for AP uptake by permeabilized glands was 51-85% of intact glands. Moreover, secretory activity was potentiated by 0.1 mM ATP. The recruitment of H(+)-K(+)-ATPase-rich tubulovesicles into the apical plasma membrane was measured using biochemical and morphological assays, thus validating the cell activation processes in response to cAMP. From this permeabilized model, [gamma-32P]ATP was used to directly phosphorylate target proteins. A number of proteins whose phosphorylation-dephosphorylation is specifically modulated by cAMP were found. These studies establish the first permeabilized gland model in which the resting-to-secreting transition can be triggered and show that cAMP-mediated phosphorylation is correlated with secretory activity.

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