Effect of chronic inflammation on electrolyte transport in rabbit ileal villus and crypt cells

1997 ◽  
Vol 272 (4) ◽  
pp. G732-G741 ◽  
Author(s):  
U. Sundaram ◽  
A. B. West
Keyword(s):  
Chronic Inflammation ◽  
Inflammatory Mediators ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Basolateral Membrane ◽  
Rabbit Model ◽  
Electrolyte Transport ◽  
Acid Load ◽  
Crypt Cells ◽  
Stimulation Of

The effect of chronic inflammation on electrolyte transport in rabbit ileal villus and crypt cells was determined with the use of a rabbit model of chronic ileitis. In both cells, Na+/H+ exchange was monitored by following recovery from an acid load, and Cl-/HCO3- exchange was monitored by following recovery from an alkaline load. In villus cells, recovery from an acid load was not affected; however, recovery from an alkaline load was slowed. These data suggest that chronic inflammation inhibits Cl-/HCO3- exchange in villus cells. In contrast, in crypt cells, recovery from an alkaline load was unaffected, whereas recovery from an acid load was accelerated. These data suggest that chronic inflammation stimulates Na+/H+ exchange in crypt cells. Inhibition of Cl-/HCO3- exchange in villus cells would be expected to inhibit coupled NaCl absorption, which occurs by the coupling of brush-border membrane (BBM) Na+/H+ and Cl-/HCO3- exchange. Stimulation of Na+/H+ exchange in crypt cells, known to be present only on the basolateral membrane, alkalinizes the cell. This alkalinization may stimulate BBM Cl-/HCO3- exchange, resulting in HCO3- secretion. Thus these unique alterations in transporter activity suggest that different endogenous immune-inflammatory mediators may have differing effects on specific transporters in villus and crypt cells in the chronically inflamed ileum.

scholarly journals Chronic and selective inhibition of basolateral membrane Na-K-ATPase uniquely regulates brush border membrane Na absorption in intestinal epithelial cells

2015 ◽  
Vol 308 (8) ◽  
pp. C650-C656 ◽  
Author(s):  
Palanikumar Manoharan ◽  
Swapna Gayam ◽  
Subha Arthur ◽  
Balasubramanian Palaniappan ◽  
Soudamani Singh ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Brush Border ◽  
Mammalian Cells ◽  
Brush Border Membrane ◽  
Intestinal Epithelial Cells ◽  
Basolateral Membrane ◽  
Selective Inhibition ◽  
Integral Membrane Protein ◽  
Intestinal Epithelial ◽  
Stimulation Of

Na-K-ATPase, an integral membrane protein in mammalian cells, is responsible for maintaining the favorable intracellular Na gradient necessary to promote Na-coupled solute cotransport processes [e.g., Na-glucose cotransport (SGLT1)]. Inhibition of brush border membrane (BBM) SGLT1 is, at least in part, due to the diminished Na-K-ATPase in villus cells from chronically inflamed rabbit intestine. The aim of the present study was to determine the effect of Na-K-ATPase inhibition on the two major BBM Na absorptive pathways, specifically Na-glucose cotransport and Na/H exchange (NHE), in intestinal epithelial (IEC-18) cells. Na-K-ATPase was inhibited using 1 mM ouabain or siRNA for Na-K-ATPase-α1in IEC-18 cells. SGLT1 activity was determined as 3- O-methyl-d-[3H]glucose uptake. Na-K-ATPase activity was measured as the amount of inorganic phosphate released. Treatment with ouabain resulted in SGLT1 inhibition at 1 h but stimulation at 24 h. To further characterize this unexpected stimulation of SGLT1, siRNA silencing was utilized to inhibit Na-K-ATPase-α1. SGLT1 activity was significantly upregulated by Na-K-ATPase silencing, while NHE3 activity remained unaltered. Kinetics showed that the mechanism of stimulation of SGLT1 activity was secondary to an increase in affinity of the cotransporter for glucose without a change in the number of cotransporters. Molecular studies demonstrated that the mechanism of stimulation was not secondary to altered BBM SGLT1 protein levels. Chronic and direct silencing of basolateral Na-K-ATPase uniquely regulates BBM Na absorptive pathways in intestinal epithelial cells. Specifically, while BBM NHE3 is unaffected, SGLT1 is stimulated secondary to enhanced affinity of the cotransporter.

scholarly journals Unique Regulation of Enterocyte Brush Border Membrane Na-Glutamine and Na-Alanine Co-Transport by Peroxynitrite during Chronic Intestinal Inflammation

2019 ◽  
Vol 20 (6) ◽  
pp. 1504 ◽  
Author(s):  
Subha Arthur ◽  
Palanikumar Manoharan ◽  
Shanmuga Sundaram ◽  
M Rahman ◽  
Balasubramanian Palaniappan ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial Cells ◽  
Rabbit Model ◽  
Intestinal Epithelial ◽  
Mechanism Of Inhibition ◽  
Chronic Intestinal Inflammation

Na-amino acid co-transporters (NaAAcT) are uniquely affected in rabbit intestinal villus cell brush border membrane (BBM) during chronic intestinal inflammation. Specifically, Na-alanine co-transport (ASCT1) is inhibited secondary to a reduction in the affinity of the co-transporter for alanine, whereas Na-glutamine co-transport (B0AT1) is inhibited secondary to a reduction in BBM co-transporter numbers. During chronic intestinal inflammation, there is abundant production of the potent oxidant peroxynitrite (OONO). However, whether OONO mediates the unique alteration in NaAAcT in intestinal epithelial cells during chronic intestinal inflammation is unknown. In this study, ASCT1 and B0AT1 were inhibited by OONO in vitro. The mechanism of inhibition of ASCT1 by OONO was secondary to a reduction in the affinity of the co-transporter for alanine, and secondary to a reduction in the number of co-transporters for B0AT1, which were further confirmed by Western blot analyses. In conclusion, peroxynitrite inhibited both BBM ASCT1 and B0AT1 in intestinal epithelial cells but by different mechanisms. These alterations in the villus cells are similar to those seen in the rabbit model of chronic enteritis. Therefore, this study indicates that peroxynitrite may mediate the inhibition of ASCT1 and B0AT1 during inflammation, when OONO levels are known to be elevated in the mucosa.

Proximal tubular dopamine production regulates basolateral Na-K-ATPase

1992 ◽  
Vol 262 (4) ◽  
pp. F566-F571 ◽  
Author(s):  
A. D. Baines ◽  
P. Ho ◽  
R. Drangova
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Sch 23390 ◽  
Basolateral Membrane ◽  
Sodium Dodecyl ◽  
Maximal Activity ◽  
Western Blots ◽  
Salt Diet ◽  
Low Salt ◽  
Proximal Tubular

Regulation of proximal tubular Na-K-adenosine-triphosphatase (ATPase), brush-border membrane Na(+)-H+ antiporter and Na(+)-Pi symporter activity by endogenously produced dopamine was examined in Wistar rats. Na-K-ATPase was measured in basolateral membrane (BLM) fractions permeabilized with alamethicin or sodium dodecyl sulfate (SDS). Carbidopa (5 mg/kg) injected 18 h before removal of kidneys increased maximal activity (Vmax) noncompetitively in cortical BLM but not in other membrane fractions or outer medullary BLM (-2 +/- 4%). Chronic renal denervation did not alter the response. Carbidopa stimulated Na-K-ATPase in cortical BLM from rats eating a normal salt diet with and without 1% saline to drink (+18 +/- 4% and +22 +/- 4%, respectively; P greater than 0.001). Carbidopa did not increase Vmax of BLM Na-K-ATPase from rats eating a low-salt diet (+1.5 +/- 4%); however, when the low-salt diet was supplemented with 1 mM dihydroxyphenylalanine (dopa) to drink for 1 day carbidopa, increased Vmax by 18 +/- 3% (P = 0.018). Carbidopa did not alter the Michaelis constant (Km) for Na or K or inhibitory constant (Ki) for ouabain. Injection of the DA1 antagonist Sch 23390 (2 mg/kg) also increased Na-K-ATPase (18 +/- 4%; P = 0.014). Western blots using a monoclonal alpha-subunit antibody revealed a 22 +/- 8% increase following carbidopa treatment (P = 0.033; n = 19 pairs). Carbidopa had no effect on Na(+)-H+ antiporter activity (22Na uptake) or on Na(+)-32Pi cotransport in brush-border membrane vesicles. These results indicate that dopamine produced in proximal tubules tonically reduces Na-K-ATPase Vmax by decreasing the number of alpha-subunits associated with the BLM.

Indirect coupling of urate and p-aminohippurate transport to sodium in human brush-border membrane vesicles

1996 ◽  
Vol 270 (1) ◽  
pp. F61-F68 ◽  
Author(s):  
F. Roch-Ramel ◽  
B. Guisan ◽  
L. Schild
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Indirect Coupling ◽  
Sodium Gradient ◽  
Beta Hydroxybutyrate ◽  
Sodium Cotransport ◽  
Stimulation Of

[14C]urate and p-[14C]aminohippurate (PAH) uptake by human brush-border membrane vesicles (BBMV) were measured in the presence of an inwardly oriented sodium gradient. No direct sodium cotransport was observed. Indirect [14C]urate coupling to sodium transport was demonstrated by cis-stimulation of [14C]urate with nicotinate or pyrazinoate (PZA) in the extravesicular medium but not by adding lactate, alpha-ketoglutarate, or beta-hydroxybutyrate. Indirect sodium coupling of [14C]PAH uptake was observed only when alpha-ketoglutarate was added to the extravesicular medium, a mechanism similar to that of basolateral membranes. The ability for PZA (and nicotinate) to cis-stimulate urate uptake was correlated with a high apparent affinity for the urate/anion exchanger. In urate-loaded vesicles, for identical medium concentrations, [14C]PZA uptake via the urateanion exchanger was 10 times higher than [14C]lactate uptake. Such high PZA affinity for the urate exchanger, working in parallel with PZA sodium cotransport can account for the stimulation of urate reabsorption by PZA in vivo.

cDNA cloning and localization of a band 3-related protein from ileum

1992 ◽  
Vol 263 (3) ◽  
pp. G345-G352 ◽  
Author(s):  
A. Chow ◽  
J. W. Dobbins ◽  
P. S. Aronson ◽  
P. Igarashi
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Band 3 ◽  
Related Protein ◽  
Rabbit Ileum ◽  
Molecular Identity ◽  
Polymerase Chain ◽  
Related Proteins

A Cl(-)-HCO3- exchanger in the brush-border membrane mediates active Cl- absorption and regulates intracellular pH in rabbit ileum. The molecular identity of the ileal Cl(-)-HCO3- exchanger has not been established. The best-characterized plasma membrane Cl(-)-HCO3- exchanger is erythroid band 3. Structurally related proteins in nonerythroid tissues comprise an anion exchanger (AE) family. We used the polymerase chain reaction to amplify and clone a cDNA encoding an ileal band 3-related protein (B3RP) from rabbit ileal enterocytes. The composite sequence is 3,909 bp and is predicted to encode a protein of 136 kDa. The deduced amino acid sequence is 95% identical to murine renal AE2, indicating that ileal B3RP is rabbit AE2. Antisera generated against a cytoplasmic fragment of ileal B3RP recognized a 160- to 170-kDa polypeptide in the brush-border membrane, but not the basolateral membrane, of ileal crypt and villus enterocytes. This correlates with previous studies indicating that a Cl(-)-HCO3- exchange is present in brush-border but not basolateral membrane vesicles from rabbit ileal enterocytes. We conclude that ileal B3RP is a product of the AE gene family, and is present in the brush-border of ileal enterocytes, where it may mediate Cl(-)-HCO3- exchange.

scholarly journals Study of the mechanism by which the Na+-Pi co-transporter of mouse kidney proximal-tubule cells adjusts to phosphate depletion

1988 ◽  
Vol 252 (1) ◽  
pp. 105-109 ◽  
Author(s):  
M Jahan ◽  
P J Butterworth
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Mouse Kidney ◽  
Transport Activity ◽  
Normal Medium ◽  
Proximal Tubule Cells ◽  
Tubule Cells ◽  
Kinetic Investigations ◽  
Stimulation Of

1. Proximal-tubule cells isolated from mouse kidney after digestion with collagenase take up Pi by an Na+-dependent and saturable process mediated by the Na+-Pi co-transporter of the brush-border membrane. 2. Pi depletion of the cells is accompanied by a stimulation of Pi-transport activity. Kinetic investigations reveal that Vmax. is increased by 90% and Km decreased by 50% after Pi depletion. Transport activity returns to normal values after incubation for 30 min at 37 degrees C of Pi-depleted cells in normal medium containing 1 mM-Pi, but the fall in transport activity under these conditions is inhibited by colchicine. 3. The energy of activation of Na+-Pi co-transport activity of depleted cells differs greatly from that found for normal replete cells. 4. The results provide evidence that stimulation of transport by Pi depletion arises from an increase in the number of carrier sites in the brush-border membrane. Additionally, changes in the properties of the transporter occur which may reflect altered phospholipid-carrier-protein interaction in the Pi-depleted condition.

Is intestinal peptide transport energized by a proton gradient?

1985 ◽  
Vol 249 (2) ◽  
pp. G153-G160 ◽  
Author(s):  
Vadivel Ganapathy ◽  
Frederick H. Leibach
Keyword(s):  
Small Intestine ◽  
Membrane Potential ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Proton Gradient ◽  
Peptide Transport ◽  
Direct Role ◽  
Mucosal Cells

Transport of intact peptides, followed by intracellular hydrolysis in the intestinal mucosal cells, plays an important role in the absorption of protein digestion products in the mammalian small intestine. Even though earlier studies on peptide absorption in intact-tissue preparations have indicated that peptides are transported by an active Na+-dependent mechanism, recent studies with purified brush-border membrane vesicles have unequivocally demonstrated that Na+ does not play a direct role in the translocation of peptides across the membrane. Like most amino acids, peptides are also transported as zwitterions. However, peptide transport causes depolarization of the brushborder membrane in intact mucosal cells as well as in purified membrane vesicles, and the depolarization is the result of a net transfer of positive charge across the membrane during peptide transport. This electrogenic nature of peptide transport is observed even in the absence of Na+. Peptide transport is enhanced by an interior-negative membrane potential and inhibited by an interior-positive membrane potential. An inward proton gradient stimulates peptide transport, and this stimulation is reduced when the proton gradient is subjected to rapid dissipation by the presence of a proton ionophore. These observations strongly suggest that peptides are cotransported with protons in the intestine. There is substantial evidence for the existence of an inward proton gradient in the mammalian small intestine, and therefore it is very likely that this proton gradient is the in vivo energy source for the uphill transport of peptides. The Na+-H+ exchanger in the brush-border membrane, in conjunction with Na+-K+-ATPase at the basolateral membrane, is probably responsible for the generation and maintenance of the proton gradient and may thus be involved indirectly in the intestinal absorption of peptides.

Oral polyamine administration modifies the ontogeny of hexose transporter gene expression in the postnatal rat intestine

2007 ◽  
Vol 293 (2) ◽  
pp. G453-G460 ◽  
Author(s):  
G. E. Wild ◽  
L. E. Searles ◽  
K. G. Koski ◽  
L. A. Drozdowski ◽  
J. Begum-Hasan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Glucose Transporter ◽  
Basolateral Membrane ◽  
Glucose Transporter 1 ◽  
Sugar Transporters ◽  
Enterocyte Proliferation ◽  
Glucose Transporter 2 ◽  
Postnatal Rats

Gastrointestinal mucosal polyamines influence enterocyte proliferation and differentiation during small intestinal maturation in the rat. Studies in postnatal rats have shown that ornithine decarboxylase (ODC) protein and mRNA peak before the maximal expression of brush-border membrane (BBM) sucrase-isomaltase (SI) and the sugar transporters sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2). This study was undertaken to test the hypothesis that the oral administration of spermidine in postnatal rats upregulates the expression of ODC, thereby enhancing the expression of SI and SGLT1 in the brush-border membrane as well as basolateral membrane-facilitative GLUT2 and Na+-K+-ATPase. Northern and Western blot analyses were performed with antibodies and cDNA probes specific for SI, SGLT1, GLUT2, α1- and β1-subunits of Na+-K+-ATPase, and ODC. Postnatal rats fed 6 μmol spermidine daily for 3 days from days 7 to 9 were killed either on postnatal day 10 (Sp10) or day 13 following a 3-day washout period (Sp13). Sp10 rats showed a precocious increase in the abundance of mRNAs for SI, SGLT1, and GLUT2 and Na+-K+-ATPase activity and α1- and β1-isoform gene expression compared with controls. ODC activity and protein and mRNA abundance were also increased in Sp10 animals. The increased expression of these genes was not sustained in Sp13 rats, suggesting that these effects were transient. Thus, 3 days of oral polyamine administration induces the precocious maturation of glucose transporters in the postnatal rat small intestine, which may be mediated by alterations in ODC expression. 1 1 Supplemental material for this article is available online at the American Journal of Physiology-Gastrointestinal and Liver Physiology website.

scholarly journals Functional vacuolar ATPase (V-ATPase) proton pumps traffic to the enterocyte brush border membrane and require CFTR

2013 ◽  
Vol 305 (9) ◽  
pp. C981-C996 ◽  
Author(s):  
Anne M. Collaco ◽  
Peter Geibel ◽  
Beth S. Lee ◽  
John P. Geibel ◽  
Nadia A. Ameen
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Basolateral Membrane ◽  
Intestinal Cells ◽  
Proton Pumps ◽  
Transmembrane Conductance Regulator ◽  
Proton Efflux ◽  
Sodium Hydrogen Exchanger ◽  
Luminal Ph ◽  
Vacuolar Atpases

Vacuolar ATPases (V-ATPases) are highly conserved proton pumps that regulate organelle pH. Epithelial luminal pH is also regulated by cAMP-dependent traffic of specific subunits of the V-ATPase complex from endosomes into the apical membrane. In the intestine, cAMP-dependent traffic of cystic fibrosis transmembrane conductance regulator (CFTR) channels and the sodium hydrogen exchanger (NHE3) in the brush border regulate luminal pH. V-ATPase was found to colocalize with CFTR in intestinal CFTR high expresser (CHE) cells recently. Moreover, apical traffic of V-ATPase and CFTR in rat Brunner's glands was shown to be dependent on cAMP/PKA. These observations support a functional relationship between V-ATPase and CFTR in the intestine. The current study examined V-ATPase and CFTR distribution in intestines from wild-type, CFTR−/−mice and polarized intestinal CaCo-2BBe cells following cAMP stimulation and inhibition of CFTR/V-ATPase function. Coimmunoprecipitation studies examined V-ATPase interaction with CFTR. The pH-sensitive dye BCECF determined proton efflux and its dependence on V-ATPase/CFTR in intestinal cells. cAMP increased V-ATPase/CFTR colocalization in the apical domain of intestinal cells and redistributed the V-ATPase Voa1 and Voa2 trafficking subunits from the basolateral membrane to the brush border membrane. Voa1 and Voa2 subunits were localized to endosomes beneath the terminal web in untreated CFTR−/−intestine but redistributed to the subapical cytoplasm following cAMP treatment. Inhibition of CFTR or V-ATPase significantly decreased pHiin cells, confirming their functional interdependence. These data establish that V-ATPase traffics into the brush border membrane to regulate proton efflux and this activity is dependent on CFTR in the intestine.

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