A vH+-ATPase is present in cultured sheep ruminal epithelial cells

2006 ◽  
Vol 291 (6) ◽  
pp. G1171-G1179 ◽  
Author(s):  
Benjamin Etschmann ◽  
Katrin Sophie Heipertz ◽  
Annabelle von der Schulenburg ◽  
Monika Schweigel
Keyword(s):  
Epithelial Cells ◽  
Primary Cultures ◽  
Selective Inhibition ◽  
Protein Band ◽  
Inhibitory Effect ◽  
B Subunit ◽  
Initial Ph ◽  
Acid Load ◽  
Acid Loading

In this study, the existence and functional activity of a vacuolar-type H+-ATPase (vH+-ATPase) was explored in primary cultures of sheep ruminal epithelial cells (REC). The mRNA transcripts of the E and B subunits of vH+-ATPase were detectable in RNA from REC samples by RT-PCR. Immunoblotting of REC protein extractions with antibodies directed against the B subunit of yeast vH+-ATPase revealed a protein band of the expected size (60 kDa). Using the fluorescent indicator BCECF and selective inhibitors (foliomycin, HOE 694, S3226), the contribution of vH+-ATPase and Na+/H+ exchanger (NHE) subtype 1 and 3 activity to the regulation of intracellular pH (pHi) was determined in nominally HCO3−-free, HEPES-buffered NaCl medium containing 20 mM of the short-chain fatty acid butyrate as well as after reduction of the extracellular Cl− concentration ([Cl−]e) from 136 to 36 mM. The initial pHi of REC was 7.4 ± 0.1 in nominally HCO3−-free, HEPES-buffered NaCl medium and 7.0 ± 0.1 after acid loading with butyrate. Selective inhibition of the vH+-ATPase with foliomycin decreased pHi by 0.19 ± 0.03 pH units. On the basis of the observed decreases in pHi resulting from inhibition of vH+-ATPase as well as of subtypes 1 and 3 of NHE, vH+-ATPase activity appears to account for ∼30% of H+ extrusion, whereas the activities of NHE subtypes 3 and 1 account for 20 and 50% of H+ extrusion, respectively. Lowering of [Cl−]e induced a pHi decrease (−0.51 ± 0.03 pH units) and impaired pHi recovery from butyrate-induced acid load. Moreover, reduction of [Cl−]e abolished the inhibitory effect of foliomycin and markedly reduced the HOE 694- and S3226-sensitive components of pHi, indicating a role of Cl− in the function of these H+ extrusion mechanisms. We conclude that a vH+-ATPase is expressed in ovine REC and plays a considerable role in the pHi regulation of these cells.

scholarly journals Rostral ventral medulla 5-HT1A receptors selectively inhibit the somatosympathetic reflex

2001 ◽  
Vol 280 (5) ◽  
pp. R1261-R1268 ◽  
Author(s):  
Takashi Miyawaki ◽  
Ann K. Goodchild ◽  
Paul M. Pilowsky
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Sympathetic Nerve Activity ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Ventrolateral Medulla ◽  
Arterial Blood ◽  
Potent Inhibition ◽  
Somatosympathetic Reflex

The role of the 5-hydroxytryptamine (5-HT1A) receptors in the rostral ventrolateral medulla (RVLM) on somatosympathetic, baroreceptor, and chemoreceptor reflexes was examined in anesthetized rats. Microinjection of the selective 5-HT1A agonist 8-hydroxy-di- n-propylamino tetralin (8-OH-DPAT) decreased arterial blood pressure and splanchnic sympathetic nerve activity (SNA). Electrical stimulation of the hindlimb evoked early and late excitatory sympathetic responses. Bilateral microinjection in the RVLM of 8-OH-DPAT markedly attenuated both the early and late responses. This potent inhibition of the somatosympathetic reflex persisted even after SNA and arterial blood pressure returned to preinjection levels. Preinjection of the selective 5-HT1A antagonist NAN-190 in the RVLM blocked the sympathoinhibitory effect of 8-OH-DPAT and attenuated the inhibitory effect on the somatosympathetic reflex. 8-OH-DPAT injected in the RVLM did not affect baroreceptor or chemoreceptor reflexes. Our findings suggest that activation of 5-HT1A receptors in the RVLM exerts a potent, selective inhibition on the somatosympathetic reflex.

Effect of curcumin on acidic pH-induced expression of IL-6 and IL-8 in human esophageal epithelial cells (HET-1A): role of PKC, MAPKs, and NF-κB

2009 ◽  
Vol 296 (2) ◽  
pp. G388-G398 ◽  
Author(s):  
Parvaneh Rafiee ◽  
Victoria M. Nelson ◽  
Sharon Manley ◽  
Michael Wellner ◽  
Martin Floer ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Mucosal Injury ◽  
Inhibitory Effect ◽  
Acidic Ph ◽  
Induced Expression ◽  
Potent Inducer ◽  
Mrna And Protein Expression ◽  
Esophageal Epithelial Cells ◽  
P38 Mapk Inhibitor

Human esophageal epithelial cells play a key role in esophageal inflammation in response to acidic pH during gastroesophageal reflux disease (GERD), increasing secretion of IL-6 and IL-8. The mechanisms underlying IL-6 and IL-8 expression and secretion in esophageal epithelial cells after acid stimulation are not well characterized. We investigated the role of PKC, MAPK, and NF-κB signaling pathways and transcriptional regulation of IL-6 and IL-8 expression in HET-1A cells exposed to acid. Exposure of HET-1A cells to pH 4.5 induced NF-κB activity and enhanced IL-6 and IL-8 secretion and mRNA and protein expression. Acid stimulation of HET-1A cells also resulted in activation of MAPKs and PKC (α and ε). Curcumin, as well as inhibitors of NF-κB (SN-50), PKC (chelerythrine), and p44/42 MAPK (PD-098059) abolished the acid-induced expression of IL-6 and IL-8. The JNK inhibitor SP-600125 blocked expression/secretion of IL-6 but only partially attenuated IL-8 expression. The p38 MAPK inhibitor SB-203580 did not inhibit IL-6 expression but exerted a stronger inhibitory effect on IL-8 expression. Together, these data demonstrate that 1) acid is a potent inducer of IL-6 and IL-8 production in HET-1A cells; 2) MAPK and PKC signaling play a key regulatory role in acid-mediated IL-6 and IL-8 expression via NF-κB activation; and 3) the anti-inflammatory plant compound curcumin inhibits esophageal activation in response to acid. Thus IL-6 and IL-8 expression by acid may contribute to the pathobiology of mucosal injury in GERD, and inhibition of the NF-κB/proinflammatory cytokine pathways may emerge as important therapeutic targets for treatment of esophageal inflammation.

A probable role of dihydropyridine receptors in repression of Ca2+ sparks demonstrated in cultured mammalian muscle

2006 ◽  
Vol 290 (2) ◽  
pp. C539-C553 ◽  
Author(s):  
Jingsong Zhou ◽  
Jianxun Yi ◽  
Leandro Royer ◽  
Bradley S. Launikonis ◽  
Adom González ◽  
...  
Keyword(s):  
Ryanodine Receptors ◽  
Critical Role ◽  
Primary Cultures ◽  
Inhibitory Effect ◽  
Wild Type ◽  
Dihydropyridine Receptors ◽  
Skeletal Muscle Contraction ◽  
Probable Role ◽  
Emission Ratios

To activate skeletal muscle contraction, action potentials must be sensed by dihydropyridine receptors (DHPRs) in the T tubule, which signal the Ca2+ release channels or ryanodine receptors (RyRs) in the sarcoplasmic reticulum (SR) to open. We demonstrate here an inhibitory effect of the T tubule on the production of sparks of Ca2+ release. Murine primary cultures were confocally imaged for Ca2+ detection and T tubule visualization. After 72 h of differentiation, T tubules extended from the periphery for less than one-third of the myotube radius. Spontaneous Ca2+ sparks were found away from the region of cells where tubules were found. Immunostaining showed RyR1 and RyR3 isoforms in all areas, implying inhibition of both isoforms by a T tubule component. To test for a role of DHPRs in this inhibition, we imaged myotubes from dysgenic mice ( mdg) that lack DHPRs. These exhibited T tubule development similar to that of normal myotubes, but produced few sparks, even in regions where tubules were absent. To increase spark frequency, a high-Ca2+ saline with 1 mM caffeine was used. Wild-type cells in this saline plus 50 μM nifedipine retained the topographic suppression pattern of sparks, but dysgenic cells in high-Ca2+ saline did not. Shifted excitation and emission ratios of indo-1 in the cytosol or mag-indo-1 in the SR were used to image [Ca2+] in these compartments. Under the conditions of interest, wild-type and mdg cells had similar levels of free [Ca2+] in cytosol and SR. These data suggest that DHPRs play a critical role in reducing the rate of spontaneous opening of Ca2+ release channels and/or their susceptibility to Ca2+-induced activation, thereby suppressing the production of Ca2+ sparks.

scholarly journals Role of Intestinal Epithelial Cells in Immune Effects Mediated by Gram-Positive Probiotic Bacteria: Involvement of Toll-Like Receptors

2005 ◽  
Vol 12 (9) ◽  
pp. 1075-1084 ◽  
Author(s):  
Gabriel Vinderola ◽  
Chantal Matar ◽  
Gabriela Perdigon
Keyword(s):  
Small Intestine ◽  
B Cells ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Primary Cultures ◽  
Clonal Expansion ◽  
Probiotic Bacteria ◽  
Intestinal Epithelial ◽  
Toll Like Receptors

ABSTRACT The mechanisms by which probiotic bacteria exert their effects on the immune system are not completely understood, but the epithelium may be a crucial player in the orchestration of the effects induced. In a previous work, we observed that some orally administered strains of lactic acid bacteria (LAB) increased the number of immunoglobulin A (IgA)-producing cells in the small intestine without a concomitant increase in the CD4+ T-cell population, indicating that some LAB strains induce clonal expansion only of B cells triggered to produce IgA. The present work aimed to study the cytokines induced by the interaction of probiotic LAB with murine intestinal epithelial cells (IEC) in healthy animals. We focused our investigation mainly on the secretion of interleukin 6 (IL-6) necessary for the clonal expansion of B cells previously observed with probiotic bacteria. The role of Toll-like receptors (TLRs) in such interaction was also addressed. The cytokines released by primary cultures of IEC in animals fed with Lactobacillus casei CRL 431 or Lactobacillus helveticus R389 were determined. Cytokines were also determined in the supernatants of primary cultures of IEC of unfed animals challenged with different concentrations of viable or nonviable lactobacilli and Escherichia coli, previously blocked or not with anti-TLR2 and anti-TLR4. We concluded that the small intestine is the place where a major distinction would occur between probiotic LAB and pathogens. This distinction comprises the type of cytokines released and the magnitude of the response, cutting across the line that separates IL-6 necessary for B-cell differentiation, which was the case with probiotic lactobacilli, from inflammatory levels of IL-6 for pathogens.

Phorbol ester-induced changes of cytoplasmic pH in neutrophils: role of exocytosis in Na+-H+ exchange

1985 ◽  
Vol 248 (3) ◽  
pp. C379-C386 ◽  
Author(s):  
S. Grinstein ◽  
B. Elder ◽  
W. Furuya
Keyword(s):  
Phorbol Ester ◽  
Secretory Granules ◽  
Cytoplasmic Ph ◽  
Ph Homeostasis ◽  
Intact Cells ◽  
Acid Load ◽  
Induced Changes ◽  
Acid Extrusion ◽  
Acid Loading

Cytoplasmic pH homeostasis was studied in intact and granule-free porcine neutrophils following activation with 12-O-tetradecanoyl-phorbol-13-acetate (TPA). In intact cells, TPA activated at least two separate processes: a Na+-independent and amiloride-insensitive acidification, and a compensatory acid extrusion. The latter is Na+ dependent and blocked by amiloride and is likely to represent Na+-H+ exchange. Enucleated and degranulated neutrophils (cytoplasts) were prepared by sedimentation of cytochalasin B-treated neutrophils through a discontinuous density gradient. Cytoplasts responded to an artificially imposed acid load with activation of an amiloride-sensitive Na+-H+ exchange. TPA also activated both acid production and Na+-dependent acid extrusion in cytoplasts. The magnitude of the responses was comparable in intact neutrophils and in cytoplasts. These data suggest that 1) the nucleus and the secretory granules are not involved in the acidifying response to TPA, and 2) exocytosis of secretory vesicles is not required for activation of Na+-H+ exchange during acid loading or following treatment with the phorbol ester TPA.

Phosphorylation of Na(+)-H+ antiporter is not stimulated by phorbol ester and acidification in granulocytic HL-60 cells

1993 ◽  
Vol 264 (5) ◽  
pp. C1278-C1284 ◽  
Author(s):  
G. N. Rao ◽  
C. Sardet ◽  
J. Pouyssegur ◽  
B. C. Berk
Keyword(s):  
Retinoic Acid ◽  
Cell Differentiation ◽  
Phorbol Ester ◽  
Functional Activity ◽  
Fold Increase ◽  
Protein Levels ◽  
Acid Load ◽  
Acid Loading ◽  
Insight Into

During differentiation of HL-60 cells into granulocyte-like cells, mRNA and protein levels for the Na(+)-H+ antiporter increased 10- to 15-fold. However, functional activity, as measured by recovery from an acid load [intracellular pH (pHi) 6.5] increased by only about twofold. In addition, basal pHi (measured in the absence of bicarbonate) increased from 7.15 to 7.26, suggesting an alteration in the antiporter's "set point" during HL-60 cell differentiation. To gain insight into the role of the Na(+)-H+ antiporter in HL-60 cell differentiation, we studied mRNA expression of the NHE-1, NHE-3, and NHE-4 isoforms. Only the NHE-1 isoform mRNA increased during differentiation. Because it has recently been shown that the antiporter is regulated by phosphorylation, we next studied NHE-1 protein phosphorylation during HL-60 cell differentiation. Differentiation by exposure to 1 microM retinoic acid for 6 days caused a 15-fold increase in the synthesis of the NHE-1 protein. However, immunoprecipitation of 32P-labeled antiporter showed a decrease in band intensity. These data indicate that during HL-60 cell differentiation, there was a net decrease in the phosphorylation of NHE-1 despite an increase in pHi. Nonetheless, recovery from an acid load (pHi 6.51) was significantly more rapid in differentiated than control cells: 62 +/- 6 vs. 38 +/- 8 mmol H+.min-1.1 cells-1, respectively. However, acid loading decreased antiporter phosphorylation by twofold in differentiated and undifferentiated HL-60 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals IL-27 Modulates Chemokine Production in TNF-α -Stimulated Human Oral Epithelial Cells

2017 ◽  
Vol 43 (3) ◽  
pp. 1198-1206 ◽  
Author(s):  
Yoshitaka Hosokawa ◽  
Ikuko Hosokawa ◽  
Kazumi Ozaki ◽  
Takashi Matsuo
Keyword(s):  
Signal Transduction ◽  
Epithelial Cells ◽  
Inhibitory Effect ◽  
Chemokine Production ◽  
Oral Epithelial Cells ◽  
Phosphorylation Level ◽  
Stat3 Phosphorylation ◽  
Tnf Α ◽  
Oral Epithelial

Background/Aims: Interleukin-27 (IL-27) is a cytokine which belongs to the IL-12 family. However, the role of IL-27 in the pathogenesis of periodontal disease is uncertain. The aim of this study was to examine the effect of IL-27 on chemokine production in TNF-α-stimulated human oral epithelial cells (TR146). Methods: We measured chemokine production in TR146 by ELISA. We used western blot analysis to detect the phosphorylation levels of signal transduction molecules, including STAT1 and STAT3 in TR146. We used inhibitors to examine the role of STAT1 and STAT3 activation. Results: IL-27 increased CXCR3 ligands production in TNF-α-stimulated TR146. Meanwhile, IL-27 suppressed IL-8 and CCL20 production induced by TNF-α. STAT1 phosphorylation level in IL-27 and TNF-α-stimulated TR146 was enhanced in comparison to TNF-α-stimulated TR146. STAT3 phosphorylation level in IL-27-treated TR146 did not change by TNF-α. Both STAT1 inhibitor and STAT3 inhibitor decreased CXCR3 ligands production. STAT1 inhibitor overrode the inhibitory effect of IL-27 on IL-8 and CCL20 production in TNF-α-stimulated TR146. Meanwhile, STAT3 inhibitor did not modulate IL-8 and CCL20 production. Conclusion: IL-27 might control leukocyte migration in periodontal lesion by modulating chemokine production from epithelial cells.

scholarly journals c-Jun-N-Terminal Kinase Signaling Is Involved in Cyclosporine-Induced Epithelial Phenotypic Changes

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Nicolas Pallet ◽  
Eric Thervet ◽  
Dany Anglicheau
Keyword(s):  
Epithelial Cells ◽  
Er Stress ◽  
Epithelial To Mesenchymal Transition ◽  
Primary Cultures ◽  
Independent Manner ◽  
Jnk Signaling ◽  
Mesenchymal Transition ◽  
Morphological Alterations ◽  
Phenotypic Changes

Tubular epithelial cells play a central role in the pathogenesis of chronic nephropathies. Previous toxicogenomic studies have demonstrated that cyclosporine- (CsA-) induced epithelial phenotypic changes (EPCs) are reminiscent of an incomplete epithelial to mesenchymal transition (EMT) in a TGF-β-independent manner. Furthermore, we identified endoplasmic reticulum (ER) stress as a potential mechanism that may participate in the modulation of tubular cell plasticity during CsA exposure. Because c-jun-N-terminal kinase (JNK), which is activated during ER stress, is implicated in kidney fibrogenesis, we undertook the current study to identify the role of JNK signaling in EPCs induced by CsA. In primary cultures of human renal epithelial cells, CsA activates JNK signaling, and the treatment with a JNK inhibitor reduces the occurrence of cell shape changes, E-cadherin downregulation, cell migration, and Snail-1 expression. Our results suggest that CsA activates JNK signaling, which, in turn, may participate in the morphological alterations through the regulation of Snail-1 expression.

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