Immunolocalization of the Na+/Ca2+ exchanger in rabbit kidney

1993 ◽  
Vol 265 (2) ◽  
pp. F327-F332 ◽  
Author(s):  
R. F. Reilly ◽  
C. A. Shugrue ◽  
D. Lattanzi ◽  
D. Biemesderfer
Keyword(s):  
Collecting Duct ◽  
Membrane Vesicle ◽  
Immunoblot Analysis ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Intracellular Loop ◽  
Nephron Segments ◽  
Vesicle Preparation

We recently isolated a cDNA encoding a Na+/Ca2+ exchanger from rabbit kidney that was highly similar to the canine cardiac sarcolemmal Na+/Ca2+ exchanger. In the present study, we used two different antibodies to the exchanger to identify the protein and establish its cellular and subcellular localization in the kidney. The first antibody was prepared against a fusion protein consisting of 190 amino acids of the large, presumably intracellular loop of the rabbit renal exchanger fused to the maltose-binding protein. The second was a monoclonal antibody generated against the isolated purified canine cardiac sarcolemmal exchanger. To identify the Na+/Ca2+ exchanger protein, we performed immunoblot analysis against a membrane vesicle preparation from rabbit kidney cortex. Both antibodies immunoblotted proteins of 120 and 70 kDa that are known to be associated with the exchanger. Indirect immunofluorescence revealed that both antisera labeled the basolateral surface of the majority of cells in the connecting tubule (CNT). Since the phase-dense (intercalated) cells in the CNT were not stained, this suggested that the labeled cells were CNT cells. No labeling was detected in other nephron segments with the exception of occasional faint staining of the majority cell population of the cortical collecting duct. The fact that we did not detect labeling in other nephron segments is consistent with either 1) the absence of expression of the Na+/Ca2+ exchanger in these segments, 2) the expression of the exchanger in levels below the threshold of detection of the two antibodies used in this study, or 3) the exchanger in these segments is represented by a different isoform.(ABSTRACT TRUNCATED AT 250 WORDS)

AE4 is a DIDS-sensitive Cl−/HCO 3 − exchanger in the basolateral membrane of the renal CCD and the SMG duct

2002 ◽  
Vol 283 (4) ◽  
pp. C1206-C1218 ◽  
Author(s):  
Shigeru B. H. Ko ◽  
Xiang Luo ◽  
Henrik Hager ◽  
Alexandra Rojek ◽  
Joo Young Choi ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Basolateral Membrane ◽  
Rabbit Kidney ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Acid Base ◽  
Specific Expression ◽  
Hek 293 ◽  
Acid Base Status ◽  
Species Specific

The renal cortical collecting duct (CCD) plays an important role in systemic acid-base homeostasis. The β-intercalated cells secrete most of the HCO[Formula: see text], which is mediated by a luminal, DIDS-insensitive, Cl−/HCO[Formula: see text] exchange. The identity of the luminal exchanger is a matter of debate. Anion exchanger isoform 4 (AE4) cloned from the rabbit kidney was proposed to perform this function (Tsuganezawa H et al. J Biol Chem 276: 8180–8189, 2001). By contrast, it was proposed (Royaux IE et al. Proc Natl Acad Sci USA 98: 4221–4226, 2001) that pendrin accomplishes this function in the mouse CCD. In the present work, we cloned, localized, and characterized the function of the rat AE4. Northern blot and RT-PCR showed high levels of AE4 mRNA in the CCD. Expression in HEK-293 and LLC-PK1 cells showed that AE4 is targeted to the plasma membrane. Measurement of intracellular pH (pHi) revealed that AE4 indeed functions as a Cl−/HCO[Formula: see text] exchanger. However, AE4 activity was inhibited by DIDS. Immunolocalization revealed species-specific expression of AE4. In the rat and mouse CCD and the mouse SMG duct AE4 was in the basolateral membrane. By contrast, in the rabbit, AE4 was in the luminal and lateral membranes. In both, the rat and rabbit CCD AE4 was in α-intercalated cells. Importantly, localization of AE4 was not affected by the systemic acid-base status of the rats. Therefore, we conclude that expression and possibly function of AE4 is species specific. In the rat and mouse AE4 functions as a Cl−/HCO[Formula: see text] exchanger in the basolateral membrane of α-intercalated cells and may participate in HCO[Formula: see text] absorption. In the rabbit AE4 may contribute to HCO[Formula: see text] secretion.

Mechanism of PGE2-induced cell swelling in distal nephron segments

1992 ◽  
Vol 263 (5) ◽  
pp. F824-F832
Author(s):  
T. Shimizu ◽  
M. Naruse ◽  
M. Takeda ◽  
M. Nakamura ◽  
K. Yoshitomi ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Cell Swelling ◽  
Rabbit Kidney ◽  
Thick Ascending Limb ◽  
Cortical Collecting Duct ◽  
Distal Nephron ◽  
Nephron Segments ◽  
Pg E2 ◽  
Dose Dependent ◽  
Sustained Increase

The effects of prostaglandin (PG) E2 on cell swelling were studied in isolated perfused tubules of rabbit kidney. PGE2 (1 microM) added to the bath induced cell swelling by 13.4, 7.2, and 9.6% in the connecting tubule, distal convoluted tubule, and cortical collecting duct, respectively, but it had no effect on the proximal convoluted tubule and cortical thick ascending limb. The response was dose dependent in the range of 1 nM to 1 microM. PGI2 exerted a similar effect, but PGF2 alpha had no effect. The swelling was completely blocked by basolateral Na+ removal and was attenuated by bilateral Cl- removal, suggesting that the swelling was mediated by basolateral Na+ entry in association with Cl- entry. In all segments except proximal tubule, PGE2 caused an initial transient peak followed by a sustained increase in intracellular Ca2+. Intracellular Ca2+ chelation or inhibition of Ca2+ release from intracellular stores abolished the PGE2-induced cell swelling, but extracellular Ca2+ removal did not. An inhibitor of the Na(+)-Ca2+ exchanger (3',4'-dichlorobenzamil, 100 microM) in the bath completely inhibited PGE2-induced cell swelling. Neither furosemide (1 mM) nor amiloride (1 mM) added to bath abolished the response, indicating that neither Na(+)-K(+)-2Cl- cotransport nor Na(+)-H+ exchange is involved in the action of PGE2. The swelling response to PGE2 was observed even in the presence of ouabain, indicating that the effect of PGE2 is independent of Na(+)-K(+)-adenosinetriphosphatase inhibition. Nicardipine added to bath partially inhibited the swelling response.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular band 3 immunostaining in type A intercalated cells of rabbit kidney

1992 ◽  
Vol 262 (6) ◽  
pp. F1015-F1022
Author(s):  
K. M. Madsen ◽  
J. Kim ◽  
C. C. Tisher
Keyword(s):  
Plasma Membrane ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Type A ◽  
Band 3 ◽  
Rabbit Kidney ◽  
Apical Plasma Membrane ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Electron Microscopic

Intercalated cells (ICs) in the collecting duct and the connecting tubule (CNT) are involved in H+ secretion and HCO3- reabsorption. H+ secretion is mediated by an H(+)-adenosinetriphosphatase in the apical plasma membrane, whereas a band 3-like Cl(-)-HCO3- exchanger in the basolateral membrane is responsible for HCO3- reabsorption. Recent studies have reported that a band 3-like protein is also present in mitochondria in rabbit ICs. The purpose of this study was to establish the subcellular location of the band 3-like Cl(-)-HCO3- exchanger in rabbit ICs by electron microscopic immunocytochemistry using a monoclonal antibody, IVF12, against erythrocyte band 3 protein. Rabbit kidneys were preserved by in vivo perfusion with a paraformaldehyde-lysine-periodate solution and processed for immunocytochemistry using a horseradish peroxidase preembedding technique. Band 3 immunostaining was observed on the basolateral plasma membrane of ICs in the outer medullary collecting duct and type A cells in the cortical collecting duct (CCD) and CNT. In addition, distinct staining for band 3 was present in numerous small vesicles and in multivesicular bodies in type A ICs in the CCD and CNT. However, there was no evidence of band 3 immunostaining of mitochondria or of the apical plasma membrane in any cells of the collecting duct. These observations suggest that basolateral Cl(-)-HCO3- exchangers in type A ICs in the rabbit kidney are stored in intracellular vesicles and possibly degraded in the vascular-lysosomal system when these cells are in a resting state. The previously reported band 3 immunolabeling of mitochondria could not be confirmed.

Pendrin: an apical Cl−/OH−/HCO3 −exchanger in the kidney cortex

2001 ◽  
Vol 280 (2) ◽  
pp. F356-F364 ◽  
Author(s):  
Manoocher Soleimani ◽  
Tracey Greeley ◽  
Snezana Petrovic ◽  
Zhaohui Wang ◽  
Hassane Amlal ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Immunoblot Analysis ◽  
Kidney Cortex ◽  
Cortical Collecting Duct ◽  
Hek 293 ◽  
Kidney Proximal Tubule ◽  
293 Cells ◽  
Nephron Segment

The identities of the apical Cl−/base exchangers in kidney proximal tubule and cortical collecting duct (CCD) cells remain unknown. Pendrin (PDS), which is expressed at high levels in the thyroid and its mutation causes Pendred's syndrome, is shown to be an anion exchanger. We investigated the renal distribution of PDS and its function. Our results demonstrate that pendrin mRNA expression in the rat kidney is abundant and limited to the cortex. Proximal tubule suspensions isolated from kidney cortex were highly enriched in pendrin mRNA. Immunoblot analysis studies localized pendrin to cortical brush-border membranes. Nephron segment RT-PCR localized pendrin mRNA to proximal tubule and CCD. Expression studies in HEK-293 cells demonstrated that pendrin functions in the Cl−/OH−, Cl−/HCO3 −, and Cl−/formate exchange modes. The conclusion is that pendrin is an apical Cl−/base exchanger in the kidney proximal tubule and CCD and mediates Cl−/OH−, Cl−/HCO3 −, and Cl−/formate exchange.

Galectin-3 expression is induced in renal β-intercalated cells during metabolic acidosis

2006 ◽  
Vol 290 (1) ◽  
pp. F148-F158 ◽  
Author(s):  
Andrew L. Schwaderer ◽  
Soundarapandian Vijayakumar ◽  
Qais Al-Awqati ◽  
George J. Schwartz
Keyword(s):  
Extracellular Matrix ◽  
Metabolic Acidosis ◽  
Collecting Duct ◽  
Rabbit Kidney ◽  
Cell Phenotype ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Outer Cortex ◽  
Galectin 3 ◽  
Inner Cortex

The adaptation of the cortical collecting duct (CCD) to metabolic acidosis requires the polymerization and deposition in the extracellular matrix of the novel protein hensin. HCO3−-secreting β-intercalated cells remove apical Cl−:HCO3− exchangers and may reverse functional polarity to secrete protons. Using intercalated cells in culture, we found that galectin-3 facilitated hensin polymerization, thereby causing their differentiation into the H+-secreting cell phenotype. We examined the expression of galectin-3 in the rabbit kidney and its relationship to hensin during metabolic acidosis. In control kidneys, galectin-3 was expressed in the cortical and medullary collecting ducts. In the outer cortex 26 ± 3% of CCD cells expressed galectin-3 compared with 64 ± 3% of the cells of the inner cortex. In the CCD, galectin-3 was rarely expressed in β-intercalated cells, being primarily present in α-intercalated and principal cells. During metabolic acidosis, the intensity of cellular staining for galectin-3 increased and more cells began to express it; the percentage of CCD cells expressing galectin-3 increased from 26 ± 3 to 66 ± 3% in the outer cortex and from 64 ± 3 to 78 ± 4% in the inner cortex. This was particularly evident in β-intercalated cells where expression was found in only 8 ± 2% in control animals but in 75 ± 2% during metabolic acidosis in the outer cortex and similarly for the inner cortex (26 ± 6 to 90 ± 7%). Importantly, both galectin-3 and hensin were found in the extracellular matrix of microdissected CCDs; and during metabolic acidosis, many more cells exhibited this extracellular colocalization. Thus galectin-3 may play several important roles in the CCD, including mediating the adaptation of β-intercalated cells during metabolic acidosis.

scholarly journals Ultrastructural localization of H+ATPase in rabbit cortical collecting duct.

1994 ◽  
Vol 4 (8) ◽  
pp. 1546-1557 ◽  
Author(s):  
J W Verlander ◽  
K M Madsen ◽  
D K Stone ◽  
C C Tisher
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Collecting Duct ◽  
Rabbit Kidney ◽  
Apical Plasma Membrane ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Thin Sections ◽  
Cytoplasmic Vesicles ◽  
Basolateral Plasma Membrane

In contrast to results obtained in the rat kidney, studies of H+ATPase localization in the rabbit kidney have failed to demonstrate basolateral plasma membrane H+ATPase immunoreactivity in intercalated cells in the cortical collecting duct (CCD). Previous studies have relied on light microscopic immunofluorescence techniques, which have limited resolution. Therefore, the immunogold procedure was used to localize H+ATPase in rabbit collecting ducts at the ultrastructural level. Rabbit kidneys were preserved in vivo with periodate-lysine-paraformaldehyde or glutaraldehyde solutions, and samples of cortex were embedded in Lowicryl K4M. Thin sections were labeled for H+ATPase by the immunogold procedure with a rabbit polyclonal antibody against the 70-kd subunit of bovine brain H+ATPase. Three patterns of localization of H+ATPase were observed. The majority of intercalated cells in the CCD exhibited label over cytoplasmic vesicles only. In these cells, no label was associated with either the apical or basolateral plasma membranes. In a second group of cells, label for H+ATPase was observed along the basolateral plasma membrane and over cytoplasmic vesicles throughout the cell. Rarely, intercalated cells with H+ATPase label along the apical plasma membrane and over the apical cytoplasmic vesicles were observed in the CCD. In the initial collecting tubule and connecting segment, intercalated cells with either pronounced apical or basolateral plasma membrane label prevailed, whereas few cells exhibited label restricted to the cytoplasmic vesicles. In summary, in the rabbit CCD, three patterns of H+ATPase distribution exist in intercalated cells, two of which conform to published models of type A and type B intercalated cells.

Localization of the ammonium transporter proteins RhBG and RhCG in mouse kidney

2003 ◽  
Vol 284 (2) ◽  
pp. F323-F337 ◽  
Author(s):  
Jill W. Verlander ◽  
R. Tyler Miller ◽  
Amy E. Frank ◽  
Ines E. Royaux ◽  
Young-Hee Kim ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Immunoblot Analysis ◽  
Mouse Kidney ◽  
Ammonium Transporter ◽  
Ammonium Transport ◽  
Apical Region ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Principal Cells ◽  
Medullary Collecting Duct

Ammonia is both produced and transported by renal epithelial cells, and it regulates renal ion transport. Recent studies have identified a family of putative ammonium transporters; mRNA for two members of this family, Rh B-glycoprotein (RhBG) and Rh C-glycoprotein (RhCG), is expressed in the kidney. The purpose of this study was to determine the cellular location of RhBG and RhCG protein in the mouse kidney. We generated RhBG- and RhCG-specific anti-peptide antibodies. Immunoblot analysis confirmed that both proteins were expressed in the mouse kidney. RhBG localization with immunohistochemistry revealed discrete basolateral labeling in the connecting segment (CNT) and in the majority of initial collecting tubule (ICT) and cortical collecting duct (CCD) cells. In the outer medullary collecting duct (OMCD) and inner medullary collecting duct (IMCD) only a subpopulation of cells exhibited basolateral immunoreactivity. Colocalization of RhBG with carbonic anhydrase II, the thiazide-sensitive transporter, and the anion exchangers AE1 and pendrin demonstrated RhBG immunoreactivity in all CNT cells and all CCD and ICT principal cells. In the ICT and CCD, basolateral RhBG immunoreactivity is also present in A-type intercalated cells but not in pendrin-positive CCD intercalated cells. In the OMCD and IMCD, only intercalated cells exhibit RhBG immunoreactivity. Immunoreactivity for a second putative ammonium transporter, RhCG, was present in the apical region of cells with almost the same distribution as RhBG. However, RhCG immunoreactivity was present in all CCD cells, and it was present in outer stripe OMCD principal cells, in addition to OMCD and IMCD intercalated cells. Thus the majority of RhBG and RhCG protein expression is present in the same epithelial cell types in the CNT and collecting duct but with opposite polarity. These findings suggest that RhBG and RhCG may play important and cell-specific roles in ammonium transport and signaling in these regions of the kidney.

Expression of the thiazide-sensitive Na-Cl cotransporter in rat and human kidney

1995 ◽  
Vol 269 (6) ◽  
pp. F900-F910 ◽  
Author(s):  
N. Obermuller ◽  
P. Bernstein ◽  
H. Velazquez ◽  
R. Reilly ◽  
D. Moser ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Human Kidney ◽  
Protein Band ◽  
Distal Region ◽  
Thick Ascending Limb ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Nephron Segments ◽  
Collecting Tubule

An electroneutral thiazide-sensitive Na-Cl cotransport pathway (TSC) has been localized functionally to the distal convoluted tubule (DCT), although the TSC has also been detected in the connecting tubule (CNT), the cortical collecting duct, and the medullary collecting tubule as well. The present experiments were designed to localize expression of message for the TSC in rat and human kidney. A riboprobe, generated from the mouse TSC, was used for in situ hybridization. Simultaneous immunocytochemistry, using antibodies to Tamm-Horsfall protein, band 3, and the Na+/Ca2+ exchanger, permitted delineation of specific nephron segments. In rat, message for the TSC was highly expressed in DCT cells but not elsewhere. The transition from thick ascending limb to DCT was abrupt, whereas the transition to CNT was gradual. In the more distal region of rat DCT (DCT-2), which contained few intercalated cells, both TSC message and Na+/Ca2+ exchanger immunoreactivity were present. Treatment of rats with furosemide for 5 days increased expression of TSC message within the DCT but did not induce its expression elsewhere. In humans, expression of TSC message was also highest in cells of the DCT. In humans, however, expression extended well into the CNT. These experiments indicate that the TSC is expressed predominantly by DCT cells in both rat and humans, although expression extends into the CNT cells in humans. They also show that the TSC and Na+/Ca2+ exchanger are coexpressed by a subpopulation of DCT cells near the junction with the CNT.

Localization of epithelial sodium channel and aquaporin-2 in rabbit kidney cortex

2000 ◽  
Vol 278 (4) ◽  
pp. F530-F539 ◽  
Author(s):  
Johannes Loffing ◽  
Dominique Loffing-Cueni ◽  
Andreas Macher ◽  
Steven C. Hebert ◽  
Beatriz Olson ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Collecting Duct ◽  
Water Channel ◽  
Distribution Patterns ◽  
Epithelial Sodium Channel ◽  
Transport Systems ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Cortical Collecting Duct ◽  
Aquaporin 2

The amiloride-sensitive epithelial sodium channel (ENaC) and the vasopressin-dependent water channel aquaporin-2 (AQP2) mediate mineralocorticoid-regulated sodium- and vasopressin-regulated water reabsorption, respectively. Distributions of ENaC and AQP2 have been shown by immunohistochemistry in rats. Functional data from rabbits suggest a different distribution pattern of these channels than in rats. We studied, by immunohistochemistry in the rabbit kidney cortex, the distributions of ENaC and AQP2, in conjunction with marker proteins for distal segments. In rabbit cortex ENaC is restricted to the connecting tubule (CNT) cells and cortical collecting duct (CCD) cells. The intracellular distribution of ENaC shifts from the apical membrane in the most upstream CNT cells to a cytoplasmic location further downstream in the CNT and in the CCD cells. AQP2 is detected in the CCD cells exclusively. The anatomic subdivisions in the rabbit distal nephron coincide exactly with distributions of apical transport systems. The differences between rabbits and rats in the distribution patterns of ENaC and AQP2 may explain functional differences in renal salt and water handling between these species.

scholarly journals Potassium depletion increases proton pump (H+-ATPase) activity in intercalated cells of cortical collecting duct

2000 ◽  
Vol 279 (1) ◽  
pp. F195-F202 ◽  
Author(s):  
Randi B. Silver ◽  
Sylvie Breton ◽  
Dennis Brown
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Collecting Duct ◽  
Proton Pumps ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Collecting Ducts ◽  
Acid Load ◽  
Collecting Tubules ◽  
Atpase Staining

Intercalated cells (ICs) from kidney collecting ducts contain proton-transporting ATPases (H+-ATPases) whose plasma membrane expression is regulated under a variety of conditions. It has been shown that net proton secretion occurs in the distal nephron from chronically K+-depleted rats and that upregulation of tubular H+- ATPase is involved in this process. However, regulation of this protein at the level of individual cells has not so far been examined. In the present study, H+-ATPase activity was determined in individually identified ICs from control and chronically K+-depleted rats (9–14 days on a low-K+ diet) by monitoring K+- and Na+-independent H+ extrusion rates after an acute acid load. Split-open rat cortical collecting tubules were loaded with the intracellular pH (pHi) indicator 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, and pHiwas determined by using ratiometric fluorescence imaging. The rate of pHi recovery in ICs in response to an acute acid load, a measure of plasma membrane H+-ATPase activity, was increased after K+ depletion to almost three times that of controls. Furthermore, the lag time before the start of pHirecovery after the cells were maximally acidified fell from 93.5 ± 13.7 s in controls to 24.5 ± 2.1 s in K+-depleted rats. In all ICs tested, Na+- and K+-independent pHi recovery was abolished in the presence of bafilomycin (100 nM), an inhibitor of the H+-ATPase. Analysis of the cell-to-cell variability in the rate of pHi recovery reveals a change in the distribution of membrane-bound proton pumps in the IC population of cortical collecting duct from K+-depleted rats. Immunocytochemical analysis of collecting ducts from control and K+-depleted rats showed that K+-depletion increased the number of ICs with tight apical H+ATPase staining and decreased the number of cells with diffuse or basolateral H+-ATPase staining. Taken together, these data indicate that chronic K+ depletion induces a marked increase in plasma membrane H+ATPase activity in individual ICs.

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