scholarly journals Effect of acid/base balance on H-ATPase 31 kD subunit mRNA levels in collecting duct cells

1995 ◽  
Vol 48 (5) ◽  
pp. 1420-1426 ◽  
Author(s):  
Géza Fejes-Tóth ◽  
Anikó Náray-Fejes-Tóth
Keyword(s):  
Collecting Duct ◽  
Mrna Levels ◽  
Acid Base Balance ◽  
Acid Base ◽  
Subunit Mrna ◽  
Duct Cells ◽  
Base Balance ◽  
Collecting Duct Cells

Regulation of AE2 mRNA expression in the cortical collecting duct by acid/base balance

1998 ◽  
Vol 274 (3) ◽  
pp. F596-F601 ◽  
Author(s):  
Géza Fejes-Tóth ◽  
Erzsébet Rusvai ◽  
Emily S. Cleaveland ◽  
Anikó Náray-Fejes-Tóth
Keyword(s):  
Mrna Expression ◽  
Collecting Duct ◽  
Cell Types ◽  
Alkaline Media ◽  
Mrna Levels ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance

AE2 mRNA and protein is expressed in several nephron segments, one of which is the cortical collecting duct (CCD). However, the distribution of AE2 among the different cell types of the CCD and the function of AE2 in the kidney are not known. The purpose of this study was to determine the distribution of AE2 mRNA among the three CCD cell types and to examine the effects of changes in acid/base balance on its expression. Following NH4Cl (acid) or NaHCO3 (base) loading of rabbits for ∼18 h, CCD cells were isolated by immunodissection. AE2 mRNA levels were determined by RT-PCR and were normalized for β-actin levels. We found that CCD cells express high levels of AE2 mRNA (∼500 copies/cell). AE2 mRNA levels were significantly higher in CCD cells originating from base-loaded than acid-loaded rabbits, with an average increase of 3.7 ± 1.07-fold. The effect of pH on AE2 mRNA levels was also tested directly using primary cultures of CCD cells. CCD cells incubated in acidic media expressed significantly lower levels of AE2 mRNA than those in normal or alkaline media. Experiments with isolated principal cells, α-intercalated cells, and β-intercalated cells (separated by fluorescence-activated cell sorting) demonstrated that AE2 mRNA levels are comparable in the three collecting duct cell subtypes and are similarly regulated by changes in acid/base balance. Based on these results, we conclude that adaptation to changes in extracellular H+ concentration is accompanied by opposite changes in AE2 mRNA expression. The observations that AE2 mRNA is not expressed in a cell-type-specific manner and that changes in acid/base balance have similar effects on each CCD cell subtype suggest that AE2 might serve a housekeeping function rather than being the apical anion exchanger of β-intercalated cells.

Aldosterone regulation of sodium channel gamma-subunit mRNA in cortical collecting duct cells

1996 ◽  
Vol 271 (1) ◽  
pp. C423-C428 ◽  
Author(s):  
D. L. Denault ◽  
G. Fejes-Toth ◽  
A. Naray-Fejes-Toth
Keyword(s):  
Nested Pcr ◽  
Collecting Duct ◽  
Na Channel ◽  
Mrna Levels ◽  
Cortical Collecting Duct ◽  
Gamma Subunit ◽  
Subunit Mrna ◽  
Duct Cells ◽  
Pcr Product ◽  
Collecting Duct Cells

Specific regulatory mechanisms of aldosterone-stimulated Na+ reabsorption through the apical amiloride-sensitive channel are unknown. In this study, we examined the effects of aldosterone on Na+ channel gamma-subunit mRNA levels in cultured rabbit cortical collecting duct cells. With the use of reverse transcriptase-polymerase chain reaction (RT-PCR) with RNA isolated from aldosterone-treated cells and degenerate primers, a 446-base pair (bp) PCR product was amplified and further characterized by nested PCR and sequencing. The nested PCR yielded a predicted 164-bp product. Sequencing of the 446-bp PCR product revealed 83% nucleotide and 91% amino acid identity to the rat colonic Na+ channel gamma-subunit. The relative abundance of Na+ channel mRNA was determined by quantitative PCR after a 24-h aldosterone treatment. The results demonstrate that Na+ channel gamma-subunit mRNA levels were significantly higher (2.6 +/- 0.42) in aldosterone-treated cultures vs. the controls. This increase, however, is less than the aldosterone-induced increase (3.2 +/- 2.0) in the amiloride-sensitive short-circuit current. These results indicate that Na+ channel gamma-subunit mRNA levels are increased by aldosterone and that this increase is likely to be responsible, at least in part, for the aldosterone-induced Na+ current in the kidney.

Long-term regulation of renal Na-dependent cotransporters and ENaC: response to altered acid-base intake

2000 ◽  
Vol 279 (3) ◽  
pp. F459-F467 ◽  
Author(s):  
Gheun-Ho Kim ◽  
Stephen W. Martin ◽  
Patricia Fernández-Llama ◽  
Shyama Masilamani ◽  
Randall K. Packer ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Na Channel ◽  
Thick Ascending Limb ◽  
Acid Base Balance ◽  
Acid Base ◽  
Opposite Pattern ◽  
Α Subunit ◽  
Base Balance ◽  
Acid Loading

Increased systemic acid intake is associated with an increase in apical Na/H exchange in the renal proximal tubule mediated by the type 3 Na/H exchanger (NHE3). Because NHE3 mediates both proton secretion and Na absorption, increased NHE3 activity could inappropriately perturb Na balance unless there are compensatory changes in Na handling. In this study, we use semiquantitative immunoblotting of rat kidneys to investigate whether acid loading is associated with compensatory decreases in the abundance of renal tubule Na transporters other than NHE3. Long-term (i.e., 7-day) acid loading with NH4Cl produced large decreases in the abundances of the thiazide-sensitive Na-Cl cotransporter (TSC/NCC) of the distal convoluted tubule and both the β- and γ-subunits of the amiloride-sensitive epithelial Na channel (ENaC) of the collecting duct. In addition, the renal cortical abundance of the proximal type 2 Na-dependent phosphate transporter (NaPi-2) was markedly decreased. In contrast, abundances of the bumetanide-sensitive Na-K-2Cl cotransporter of the thick ascending limb and the α-subunit of ENaC were unchanged. A similar profile of changes was seen with short-term (16-h) acid loading. Long-term (7-day) base loading with NaHCO3resulted in the opposite pattern of response with marked increases in the abundances of the β- and γ-subunits of ENaC and NaPi-2. These adaptations may play critical roles in the maintenance in Na balance when changes in acid-base balance occur.

(PRO)RENIN RECEPTOR IN THE KIDNEY: FUNCTION AND SIGNIFICANCE

2021 ◽  
Author(s):  
Gertrude Arthur ◽  
Jeffrey L. Osborn ◽  
Frederique B. Yiannikouris
Keyword(s):  
Intracellular Signaling ◽  
Collecting Duct ◽  
Renin Angiotensin System ◽  
Cortical Collecting Duct ◽  
Acid Base Balance ◽  
Acid Base ◽  
Kidney Fibrosis ◽  
Prorenin Receptor ◽  
Base Balance ◽  
And Function

Prorenin receptor (PRR), a 350-amino acid receptor initially thought of as a receptor for the binding of renin and prorenin has been shown to be multifunctional. In addition to its role in the renin angiotensin system (RAS), PRR also transduces several intracellular signaling molecules and is a component of the vacuolar H+-ATPase that participates in autophagy. PRR is found in the kidney and particularly in great abundance in the cortical collecting duct. In the kidney, PRR participates in water and salt balance, acid-base balance, autophagy and plays a role in development and progression of hypertension, diabetic retinopathy, and kidney fibrosis. This review highlights the role of PRR in the development and function of the kidney namely the macula densa, podocyte, proximal and distal convoluted tubule and the principal cells of the collecting duct and focuses on PRR function in body fluid volume homeostasis, blood pressure regulation and acid-base balance. This review also explores new advances in the molecular mechanism involving PRR in normal renal health and pathophysiological states.

Functional upregulation of H+-ATPase by lethal acid stress in cultured inner medullary collecting duct cells

1997 ◽  
Vol 273 (4) ◽  
pp. C1194-C1205 ◽  
Author(s):  
Hassane Amlal ◽  
Zhaohui Wang ◽  
Manoocher Soleimani
Keyword(s):  
Collecting Duct ◽  
Acid Stress ◽  
Northern Hybridization ◽  
Mrna Levels ◽  
Inner Medullary Collecting Duct ◽  
Duct Cells ◽  
Acid Load ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct ◽  
Mutant Cells

The response of H+-ATPase to lethal acid stress is unknown. A mutant strain (called NHE2d) was derived from cultured inner medullary collecting duct cells (mIMCD-3 cells) following three cycles of lethal acid stress. Cells were grown to confluence on coverslips, loaded with 2′,7′-bis(carboxyethyl)-5(6)-carboxyfluorescein, and monitored for intracellular pH (pHi) recovery from an acid load. The rate of Na+-independent pHi recovery from an acid load in mutant cells was approximately fourfold higher than in parent cells ( P < 0.001). The Na+-independent H+ extrusion was ATP dependent and K+ independent and was completely inhibited in the presence of diethylstilbestrol, N, N′-dicyclohexylcarbodiimide, or N-ethylmaleimide. These results indicate that the Na+-independent H+ extrusion in cultured medullary cells is mediated via H+-ATPase and is upregulated in lethal acidosis. Northern hybridization experiments demonstrated that mRNA levels for the 16- and 31-kDa subunits of H+-ATPase remained unchanged in mutant cells compared with parent cells. We propose that lethal acid stress results in increased H+-ATPase activity in inner medullary collecting duct cells. Upregulation of H+-ATPase could play a protective role against cell death in severe intracellular acidosis.

scholarly journals Physical and functional interaction of Rnf2 with Af9 regulates basal and aldosterone-stimulated transcription of the α-ENaC gene in a renal collecting duct cell line

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Zhi-Yuan Yu ◽  
Qun Kong ◽  
Bruce C. Kone
Keyword(s):  
Glutathione Transferase ◽  
Collecting Duct ◽  
Chromosome 9 ◽  
Na Channel ◽  
Central Component ◽  
Mrna Levels ◽  
Functional Interaction ◽  
Α Subunit ◽  
Duct Cells ◽  
Collecting Duct Cells

The physical and functional interaction of Rnf2 (RING finger protein 2), a central component of the PRC (Polycomb repressive complex) 1 and Af9 (ALL1-fused gene from chromosome 9 protein), an aldosterone-sensitive transcription factor, in regulating basal and aldosterone-stimulated transcription of the α-ENaC (epithelial Na+ channel α-subunit) gene was explored in mIMCD3 CD (collecting duct) cells. Since Rnf2 lacks DNA-specific binding activity, other factors must mediate its site-specific chromatin recruitment. Rnf2 and Af9 co-localized in the nucleus and co-immunoprecipitated. A GST (glutathione transferase)–Af9 carboxy-terminal fusion protein directly interacted with in vitro translated Rnf2 in GST pull-down assays. Rnf2 knock down enhanced basal and aldosterone-stimulated α-ENaC mRNA levels and α-ENaC promoter activity. ChIP/QPCR (chromatin immunoprecipitation/quantitative PCR) assays demonstrated enrichment of Rnf2, H2AK119 (mono-ubiquitinated histone H2A lysine 119), and H3K27me3 (histone H3 lysine 27 trimethylated), a PRC2 chromatin mark, at multiple α-ENaC promoter subregions corresponding to regions of known Af9 enrichment, under basal conditions. Sequential ChIP confirmed Rnf2–Af9 co-occupancy of the α-ENaC promoter. Aldosterone provoked early and sustained depletion of Rnf2, ubiquitinated H2AK119, and trimethylated H3K27 associated with the subregions of the α-ENaC promoter. Thus, Af9 mediates site-selective physical and functional recruitment of Rnf2 to the α-ENaC promoter to constrain basal α-ENaC transcription in collecting duct cells, and aldosterone reverses this process.

Expression of colonic H-K-ATPase mRNA in cortical collecting duct: regulation by acid/base balance

1995 ◽  
Vol 269 (4) ◽  
pp. F551-F557 ◽  
Author(s):  
G. Fejes-Toth ◽  
E. Rusvai ◽  
K. A. Longo ◽  
A. Naray-Fejes-Toth
Keyword(s):  
Amino Acid ◽  
Collecting Duct ◽  
Predicted Amino Acid Sequence ◽  
Cortical Collecting Duct ◽  
Acid Base Balance ◽  
Acid Base ◽  
Pcr Product ◽  
Exact Function ◽  
Degenerate Oligonucleotide ◽  
Base Balance

In addition to the gastric isoform of H-K-ATPase, the colonic isoform is also expressed in the kidney, but its intrarenal localization and exact function are not known. The goal of this study was to determine whether the colonic H-K-ATPase is expressed in the rabbit cortical collecting duct (CCD) and whether it is regulated by changes in acid/base balance. With quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) with RNA isolated from immunodissected rabbit CCD cells and degenerate oligonucleotide primers, a PCR product of the predicted size (approximately 430 bp) was amplified. The amplified DNA was further characterized by nested PCR and sequencing. Direct sequencing of the 434-bp PCR product revealed 83% identity at the nucleotide level and an 80.4% identity at the deduced amino acid level to the rat colonic H-K-ATPase. With the same primers and cDNA originating from rabbit distal colon, a DNA fragment with a size and nucleotide sequence identical to that originating from CCD cells was amplified. Furthermore, using PCR screening, we isolated and sequenced a 1.5-kb cDNA clone from a rabbit CCD library. The predicted amino acid sequence of the protein encoded by this cDNA is 85 and 82% identical to the corresponding regions of the guinea pig and rat colonic H-K-ATPase, respectively, and 70% identical to the H-K-ATPase recently cloned from Bufo marinus, whereas it shows only 45 and 42% homology to the rat Na-K-ATPase alpha 1-subunit and the rat gastric H-K-ATPase, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals New insights into the dynamic regulation of water and acid-base balance by renal epithelial cells

2012 ◽  
Vol 302 (10) ◽  
pp. C1421-C1433 ◽  
Author(s):  
Dennis Brown ◽  
Richard Bouley ◽  
Teodor G. Pǎunescu ◽  
Sylvie Breton ◽  
Hua A. J. Lu
Keyword(s):  
Cell Biology ◽  
Collecting Duct ◽  
Water Channel ◽  
Proton Pumping ◽  
Renal Tubules ◽  
Intercalated Cells ◽  
Acid Base Balance ◽  
Acid Base ◽  
Major Function ◽  
Base Balance

Maintaining tight control over body fluid and acid-base homeostasis is essential for human health and is a major function of the kidney. The collecting duct is a mosaic of two cell populations that are highly specialized to perform these two distinct processes. The antidiuretic hormone vasopressin (VP) and its receptor, the V2R, play a central role in regulating the urinary concentrating mechanism by stimulating accumulation of the aquaporin 2 (AQP2) water channel in the apical membrane of collecting duct principal cells. This increases epithelial water permeability and allows osmotic water reabsorption to occur. An understanding of the basic cell biology/physiology of AQP2 regulation and trafficking has informed the development of new potential treatments for diseases such as nephrogenic diabetes insipidus, in which the VP/V2R/AQP2 signaling axis is defective. Tubule acidification due to the activation of intercalated cells is also critical to organ function, and defects lead to several pathological conditions in humans. Therefore, it is important to understand how these “professional” proton-secreting cells respond to environmental and cellular cues. Using epididymal proton-secreting cells as a model system, we identified the soluble adenylate cyclase (sAC) as a sensor that detects luminal bicarbonate and activates the vacuolar proton-pumping ATPase (V-ATPase) via cAMP to regulate tubular pH. Renal intercalated cells also express sAC and respond to cAMP by increasing proton secretion, supporting the hypothesis that sAC could function as a luminal sensor in renal tubules to regulate acid-base balance. This review summarizes recent advances in our understanding of these fundamental processes.

scholarly journals Slc4a8 in the Kidney: Expression, Subcellular Localization and Role in Salt Reabsorption

2018 ◽  
Vol 50 (4) ◽  
pp. 1361-1375 ◽  
Author(s):  
Jie Xu ◽  
Sharon Barone ◽  
Kamyar Zahedi ◽  
Marybeth Brooks ◽  
Manoocher Soleimani
Keyword(s):  
In Situ Hybridization ◽  
Subcellular Localization ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Acid Base ◽  
Duct Cells ◽  
Collecting Ducts ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct

Background/Aims: The sodium-dependent bicarbonate transporter Slc4a8 (a.k.a NDCBE) mediates the co-transport of sodium and bicarbonate in exchange for chloride. It is abundantly detected in the brain, with low expression levels in the kidney. The cell distribution and subcellular localization of Slc4a8 in the kidney and its role in acid/base and electrolyte homeostasis has been the subject of conflicting reports. There are no conclusive localization or functional studies to pinpoint the location and demonstrate the function of Slc4a8 in the kidney. Methods: Molecular techniques, including RT-PCR and in situ hybridization, were performed on kidney sections and tagged epitopes were used to examine the membrane targeting of Slc4a8 in polarized kidney cells. Crispr/Cas9 was used to generate and examine Slc4a8 KO mice. Results: Zonal distribution and in situ hybridization studies showed very little expression for Slc4a8 (NDCBE) in the cortex or in cortical collecting ducts (CCD). Slc4a8 was predominantly detected in the outer and inner medullary collecting ducts (OMCD and IMCD), and was targeted to the basolateral membrane of osmotically tolerant MDCK cells. Slc4a8 KO mice did not show any abnormal salt or bicarbonate wasting under baseline conditions or in response to bicarbonate loading, salt restriction or furosemide-induced diuresis. Conclusion: Slc4a8 (NDCBE) is absent in the CCD and is predominantly localized on the basolateral membrane of medullary collecting duct cells. Further, Slc4a8 deletion does not cause significant acid base or electrolyte abnormalities in pathophysiologic states. Additional studies are needed to examine the role of Slc4a8 (NDCBE) in intracellular pH and volume regulation in medullary collecting duct cells.

Regulated expression of pendrin in rat kidney in response to chronic NH4Cl or NaHCO3 loading

2003 ◽  
Vol 284 (3) ◽  
pp. F584-F593 ◽  
Author(s):  
Sebastian Frische ◽  
Tae-Hwan Kwon ◽  
Jørgen Frøkiær ◽  
Kirsten M. Madsen ◽  
Søren Nielsen
Keyword(s):  
Plasma Membrane ◽  
Sodium Intake ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Apical Plasma Membrane ◽  
Cortical Collecting Duct ◽  
Acid Base Balance ◽  
Acid Base ◽  
Control Value ◽  
Base Balance

The anion exchanger pendrin is present in the apical plasma membrane of type B and non-A-non-B intercalated cells of the cortical collecting duct (CCD) and connecting tubule and is involved in HCO[Formula: see text]secretion. In this study, we investigated whether the abundance and subcellular localization of pendrin are regulated in response to experimental metabolic acidosis and alkalosis with maintained water and sodium intake. NH4Cl loading (0.033 mmol NH4Cl/g body wt for 7 days) dramatically reduced pendrin abundance to 22 ± 4% of control values ( n = 6, P < 0.005). Immunoperoxidase labeling for pendrin showed reduced intensity in NH4Cl-loaded animals compared with control animals. Moreover, double-label laser confocal microscopy revealed a reduction in the fraction of cells in the CCD exhibiting pendrin labeling to 65% of the control value ( n = 6, P < 0.005). Conversely, NaHCO3 loading (0.033 mmol NaHCO3/g body wt for 7 days) induced a significant increase in pendrin expression to 153 ± 11% of control values ( n = 6, P < 0.01) with no change in the fraction of cells expressing pendrin. Immunoelectron microscopy revealed no major changes in the subcellular distribution, with abundant labeling in both the apical plasma membrane and the intracellular vesicles in all conditions. These results indicate that changes in pendrin protein expression play a key role in the well-established regulation of HCO[Formula: see text] secretion in the CCD in response to chronic changes in acid-base balance and suggest that regulation of pendrin expression may be clinically important in the correction of acid-base disturbances.

Sign in / Sign up

Export Citation Format

Share Document