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Ayasse N, Berg P, Svendsen SL, Rousing AQ, Sørensen MV, Fedosova NU, Leipziger J. Trimethoprim inhibits renal H +-K +-ATPase in states of K + depletion. Am J Physiol Renal Physiol 2024; 326:F143-F151. [PMID: 37942538 DOI: 10.1152/ajprenal.00273.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/23/2023] [Accepted: 11/06/2023] [Indexed: 11/10/2023] Open
Abstract
There is growing consensus that under physiological conditions, collecting duct H+ secretion is independent of epithelial Na+ channel (ENaC) activity. We have recently shown that the direct ENaC inhibitor benzamil acutely impairs H+ excretion by blocking renal H+-K+-ATPase. However, the question remains whether inhibition of ENaC per se causes alterations in renal H+ excretion. To revisit this question, we studied the effect of the antibiotic trimethoprim (TMP), which is well known to cause K+ retention by direct ENaC inhibition. The acute effect of TMP (5 µg/g body wt) was assessed in bladder-catheterized mice, allowing real-time measurement of urinary pH, electrolyte, and acid excretion. Dietary K+ depletion was used to increase renal H+-K+-ATPase activity. In addition, the effect of TMP was investigated in vitro using pig gastric H+-K+-ATPase-enriched membrane vesicles. TMP acutely increased natriuresis and decreased kaliuresis, confirming its ENaC-inhibiting property. Under control diet conditions, TMP had no effect on urinary pH or acid excretion. Interestingly, K+ depletion unmasked an acute urine alkalizing effect of TMP. This finding was corroborated by in vitro experiments showing that TMP inhibits H+-K+-ATPase activity, albeit at much higher concentrations than benzamil. In conclusion, under control diet conditions, TMP inhibited ENaC function without changing urinary H+ excretion. This finding further supports the hypothesis that the inhibition of ENaC per se does not impair H+ excretion in the collecting duct. Moreover, TMP-induced urinary alkalization in animals fed a low-K+ diet highlights the importance of renal H+-K+-ATPase-mediated H+ secretion in states of K+ depletion.NEW & NOTEWORTHY The antibiotic trimethoprim (TMP) often mediates K+ retention and metabolic acidosis. We suggest a revision of the underlying mechanism that causes metabolic acidosis. Our results indicate that TMP-induced metabolic acidosis is secondary to epithelial Na+ channel-dependent K+ retention. Under control dietary conditions, TMP does not per se inhibit collecting duct H+ secretion. These findings add further argument against a physiologically relevant voltage-dependent mechanism of collecting duct H+ excretion.
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Affiliation(s)
- Niklas Ayasse
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
- Vth Department of Medicine, University Hospital Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Peder Berg
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | - Samuel L Svendsen
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | | | | | - Natalya U Fedosova
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | - Jens Leipziger
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
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Abe K, Nishizawa T, Artigas P. An unusual conformation from Na +-sensitive non-gastric proton pump mutants reveals molecular mechanisms of cooperative Na +-binding. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119543. [PMID: 37482134 DOI: 10.1016/j.bbamcr.2023.119543] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/29/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023]
Abstract
The Na+,K+-ATPase (NKA) and non-gastric H+,K+- ATPase (ngHKA) share ~65 % sequence identity, and nearly identical catalytic cycles. These pumps alternate between inward-facing (E1) and outward-facing (E2) conformations and differ in their exported substrate (Na+ or H+) and stoichiometries (3 Na+:2 K+ or 1 H+:1 K+). We reported that structures of the NKA-mimetic ngHKA mutant K794S/A797P/W940/R949C (SPWC) with 2 K+ occluded in E2-Pi and 3 Na+-bound in E1·ATP states were nearly identical to NKA structures in equivalent states. Here we report the cryo-EM structures of K794A and K794S, two poorly-selective ngHKA mutants, under conditions to stabilize the E1·ATP state. Unexpectedly, the structures show a hybrid with both E1- and E2-like structural features. While transmembrane segments TM1-TM3 and TM4's extracellular half adopted an E2-like conformation, the rest of the protein assumed an E1 configuration. Two spherical densities, likely bound Na+, were observed at cation-binding sites I and III, without density at site II. This explains the E2-like conformation of TM4's exoplasmic half. In NKA, oxygen atoms derived from the unwound portion of TM4 coordinated Na+ at site II. Thus, the lack of Na+ at site II of K794A/S prevents the luminal portion of TM4 from taking an E1-like position. The K794A structure also suggests that incomplete coordination of Na+ at site III induces the halfway rotation of TM6, which impairs Na+-binding at the site II. Thus, our observations provide insight into the molecular mechanism of E2-E1 transition and cooperative Na+-binding in the NKA and other related cation pumps.
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Affiliation(s)
- Kazuhiro Abe
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya 464-8601, Japan; Cellular and Structural Physiology Institute, Nagoya University, Nagoya 464-8601, Japan; Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Japan.
| | - Tomohiro Nishizawa
- Graduate School of Medical Life Sciences, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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Lasaad S, Walter C, Rafael C, Morla L, Doucet A, Picard N, Blanchard A, Fromes Y, Matot B, Crambert G, Cheval L. GDF15 mediates renal cell plasticity in response to potassium depletion in mice. Acta Physiol (Oxf) 2023; 239:e14046. [PMID: 37665159 DOI: 10.1111/apha.14046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 08/17/2023] [Accepted: 08/23/2023] [Indexed: 09/05/2023]
Abstract
OBJECTIVE To understand the mechanisms involved in the response to a low-K+ diet (LK), we investigated the role of the growth factor GDF15 and the ion pump H,K-ATPase type 2 (HKA2) in this process. METHODS Male mice of different genotypes (WT, GDF15-KO, and HKA2-KO) were fed an LK diet for different periods of time. We analyzed GDF15 levels, metabolic and physiological parameters, and the cellular composition of collecting ducts. RESULTS Mice fed an LK diet showed a 2-4-fold increase in plasma and urine GDF15 levels. Compared to WT mice, GDF15-KO mice rapidly developed hypokalemia due to impaired renal adaptation. This is related to their 1/ inability to increase the number of type A intercalated cells (AIC) and 2/ absence of upregulation of H,K-ATPase type 2 (HKA2), the two processes responsible for K+ retention. Interestingly, we showed that the GDF15-mediated proliferative effect on AIC was dependent on the ErbB2 receptor and required the presence of HKA2. Finally, renal leakage of K+ induced a reduction in muscle mass in GDF15-KO mice fed LK diet. CONCLUSIONS In this study, we showed that GDF15 and HKA2 are linked and play a central role in the response to K+ restriction by orchestrating the modification of the cellular composition of the collecting duct.
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Affiliation(s)
- Samia Lasaad
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
| | - Christine Walter
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
| | - Chloé Rafael
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
| | - Luciana Morla
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
| | - Alain Doucet
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
| | - Nicolas Picard
- Laboratory of Tissue Biology and Therapeutic Engineering, UMR 5305 CNRS, University Lyon 1, Lyon, France
| | - Anne Blanchard
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Centre d'Investigation Clinique, Paris, France
| | - Yves Fromes
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | - Béatrice Matot
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | - Gilles Crambert
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
| | - Lydie Cheval
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Unité Métabolisme et Physiologie Rénale, Paris, France
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Lasaad S, Crambert G. Renal K + retention in physiological circumstances: focus on adaptation of the distal nephron and cross-talk with Na + transport systems. Front Physiol 2023; 14:1264296. [PMID: 37719462 PMCID: PMC10500064 DOI: 10.3389/fphys.2023.1264296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/18/2023] [Indexed: 09/19/2023] Open
Abstract
Consumption of salt (NaCl) and potassium (K+) has been completely modified, switching from a rich-K+/low-NaCl diet in the hunter-gatherer population to the opposite in the modern, westernized population. The ability to conserve K+ is crucial to maintain the plasma K+ concentration in a physiological range when dietary K+ intake is decreased. Moreover, a chronic reduction in the K+ intake is correlated with an increased blood pressure, an effect worsened by a high-Na+ diet. The renal adaptation to a low-K+ diet in order to maintain the plasma K+ level in the normal range is complex and interconnected with the mechanisms of the Na+ balance. In this short review, we will recapitulate the general mechanisms allowing the plasma K+ value to remain in the normal range, when there is a necessity to retain K+ (response to low-K+ diet and adaptation to gestation), by focusing on the processes occurring in the most distal part of the nephron. We will particularly outline the mechanisms of K+ reabsorption and discuss the consequences of its absence on the Na+ transport systems and the regulation of the extracellular compartment volume and blood pressure.
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Affiliation(s)
- Samia Lasaad
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
- CNRS EMR 8228—Unité Métabolisme et Physiologie Rénale, Paris, France
| | - Gilles Crambert
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
- CNRS EMR 8228—Unité Métabolisme et Physiologie Rénale, Paris, France
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Structure and function of H +/K + pump mutants reveal Na +/K + pump mechanisms. Nat Commun 2022; 13:5270. [PMID: 36085139 PMCID: PMC9463140 DOI: 10.1038/s41467-022-32793-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/17/2022] [Indexed: 11/09/2022] Open
Abstract
Ion-transport mechanisms evolve by changing ion-selectivity, such as switching from Na+ to H+ selectivity in secondary-active transporters or P-type-ATPases. Here we study primary-active transport via P-type ATPases using functional and structural analyses to demonstrate that four simultaneous residue substitutions transform the non-gastric H+/K+ pump, a strict H+-dependent electroneutral P-type ATPase, into a bona fide Na+-dependent electrogenic Na+/K+ pump. Conversion of a H+-dependent primary-active transporter into a Na+-dependent one provides a prototype for similar studies of ion-transport proteins. Moreover, we solve the structures of the wild-type non-gastric H+/K+ pump, a suitable drug target to treat cystic fibrosis, and of its Na+/K+ pump-mimicking mutant in two major conformations, providing insight on how Na+ binding drives a concerted mechanism leading to Na+/K+ pump phosphorylation.
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Liu B, Zhao T, Li Y, Han Y, Xu Y, Yang H, Wang S, Zhao Y, Li P, Wang Y. Notoginsenoside R1 ameliorates mitochondrial dysfunction to circumvent neuronal energy failure in acute phase of focal cerebral ischemia. Phytother Res 2022; 36:2223-2235. [PMID: 35419891 DOI: 10.1002/ptr.7450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 02/03/2022] [Accepted: 03/08/2022] [Indexed: 11/10/2022]
Abstract
Due to sudden loss of cerebral blood circulation, acute ischemic stroke (IS) causes neuronal energy attenuation or even exhaustion by mitochondrial dysfunction resulting in aggravation of neurological injury. In this study, we investigated if Notoginsenoside R1 ameliorated cerebral energy metabolism by limiting neuronal mitochondrial dysfunction in acute IS. Male Sprague-Dawley rats (260-280 g) were selected and performed by permanent middle cerebral artery occlusion model. In vitro, the oxygen glucose deprivation (OGD) model of Neuro2a (N2a) cells was established. We found Notoginsenoside R1 treatment reduced rats' cerebral infarct volume and neurological deficits, with increased Adenosine triphosphate (ATP) level together with upregulated expression of glucose transporter 1/3, monocarboxylate transporter 1 and citrate synthase in brain peri-ischemic tissue. In vitro, OGD-induced N2a cell death was inhibited, cell mitochondrial morphology was improved. Mitochondrial amount, mitochondrial membrane potential, and mitochondrial DNA copy number were increased by Notoginsenoside R1 administration. Furthermore, mitochondrial energy metabolism-related mRNA array found Atp12a and Atp6v1g3 gene expression were upregulated more than twofold, which were also verified in rat ischemic tissue by quantitative polymerase chain reaction (qPCR) assay. Therefore, Notoginsenoside R1 administration increases cerebral glucose and lactate transportation and ATP levels, ameliorates neuronal mitochondrial function after IS. Notoginsenoside R1 may be a novel protective agent for neuronal mitochondria poststroke.
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Affiliation(s)
- Bowen Liu
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao SAR, China
| | - Tingting Zhao
- Faculty of Chinese Medicine, Macau University of Science and Technology, Macao SAR, China
| | - Yiyang Li
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao SAR, China
| | - Yan Han
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao SAR, China
| | - Youhua Xu
- Faculty of Chinese Medicine, Macau University of Science and Technology, Macao SAR, China
| | - Hua Yang
- State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Shengpeng Wang
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao SAR, China
| | - Yonghua Zhao
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao SAR, China
| | - Ping Li
- State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yitao Wang
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao SAR, China
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7
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Favia M, Gerbino A, Notario E, Tragni V, Sgobba MN, Dell’Aquila ME, Pierri CL, Guerra L, Ciani E. The Non-Gastric H+/K+ ATPase (ATP12A) Is Expressed in Mammalian Spermatozoa. Int J Mol Sci 2022; 23:ijms23031048. [PMID: 35162971 PMCID: PMC8835340 DOI: 10.3390/ijms23031048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 12/10/2022] Open
Abstract
H+/K+ ATPase Type 2 is an heteromeric membrane protein involved in cation transmembrane transport and consists of two subunits: a specific α subunit (ATP12A) and a non-specific β subunit. The aim of this study was to demonstrate the presence and establish the localization of ATP12A in spermatozoa from Bubalus bubalis, Bos taurus and Ovis aries. Immunoblotting revealed, in all three species, a major band (100 kDa) corresponding to the expected molecular mass. The ATP12A immunolocalization pattern showed, consistently in the three species, a strong signal at the acrosome. These results, described here for the first time in spermatozoa, are consistent with those observed for the β1 subunit of Na+/K+ ATPase, suggesting that the latter may assemble with the α subunit to produce a functional ATP12A dimer in sperm cells. The above scenario appeared to be nicely supported by 3D comparative modeling and interaction energy calculations. The expression of ATP12A during different stages of bovine sperm maturation progressively increased, moving from epididymis to deferent ducts. Based on overall results, we hypothesize that ATP12A may play a role in acrosome reactions. Further studies will be required in order to address the functional role of this target protein in sperm physiology.
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Giusti S, Lin Y, Sogbetun F, Nakhoul N, Liu S, Shi L, Batuman V. The Effect of Proton Pump Inhibitor Use on the Course of Kidney Function in Patients with Chronic Kidney Disease Stages G3a to G4. Am J Med Sci 2021; 362:453-461. [PMID: 34033809 DOI: 10.1016/j.amjms.2021.05.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 04/07/2021] [Accepted: 05/20/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Proton pump inhibitors (PPI) are widely used and implicated in the progression of chronic kidney disease (CKD). We evaluated the relation between chronic PPI use in veterans with CKD G3a to G4 and the rate of decline in renal function. METHODS We accessed the Veteran Affairs Informatics and Computing Infrastructure national database to evaluate the relation between chronic PPI use and rate of decline in renal function in veterans with CKD (eGFR <60 ml/min1.73 m2). We applied Propensity Score Matching to match the PPI group and the no-PPI control group on age, sex, race, and Charlson Comorbidity Index. The final sample included 1406 patients (age: 62.07±7.82, 62.02% Caucasian) in the PPI cohort with a median 4.7 years follow-up and 1425 patients (age: 65.45±6.58, 71.16% Caucasian) in the control cohort with a median 3.9 years follow-up. Kaplan-Meier curve and Cox regression were performed to analyze the associations of PPI use with dialysis, all-cause mortality, metabolic acidosis, and CKD progression. RESULTS The PPI group had a significantly increased risk of CKD progression, dialysis and all-cause mortality (aHR, 1.83; 95% CI, 1.53 to 2.19; aHR, 1.84; 95% CI, 1.26 to 2.67; and aHR, 1.34; 95% CI, 1.08 to 1.65, respectively). The PPI cohort also had a trend for development of metabolic acidosis (aHR, 1.34; 95% CI, 0.998 to 1.80), although the difference was not statistically significant. CONCLUSIONS The data suggest that chronic PPI use accelerates progression of kidney disease and is associated with increased mortality in CKD patients.
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Affiliation(s)
- Sixto Giusti
- Tulane University School of Medicine, Deming Department of Medicine, Section of Nephrology, New Orleans, Louisiana; Southeast Louisiana Veterans Health Care System, Medicine Service, Section of Nephrology, New Orleans, Louisiana.
| | - Yilu Lin
- Tulane University School of Public Health Department of Global Health Management and Policy (GHMP) Tulane University School of Public Health and Tropical Medicine (TUSPHTM), New Orleans, Louisiana
| | - Folarin Sogbetun
- Tulane University School of Medicine, Deming Department of Medicine, Section of Nephrology, New Orleans, Louisiana
| | - Nazih Nakhoul
- Tulane University School of Medicine, Deming Department of Medicine, Section of Nephrology, New Orleans, Louisiana
| | - Shuqian Liu
- Tulane University School of Public Health Department of Global Health Management and Policy (GHMP) Tulane University School of Public Health and Tropical Medicine (TUSPHTM), New Orleans, Louisiana
| | - Lizheng Shi
- Tulane University School of Public Health Department of Global Health Management and Policy (GHMP) Tulane University School of Public Health and Tropical Medicine (TUSPHTM), New Orleans, Louisiana
| | - Vecihi Batuman
- Tulane University School of Medicine, Deming Department of Medicine, Section of Nephrology, New Orleans, Louisiana; Southeast Louisiana Veterans Health Care System, Medicine Service, Section of Nephrology, New Orleans, Louisiana
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9
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Mullins L, Ivy J, Ward M, Tenstad O, Wiig H, Kitada K, Manning J, Rakova N, Muller D, Mullins J. Abnormal neonatal sodium handling in skin precedes hypertension in the SAME rat. Pflugers Arch 2021; 473:897-910. [PMID: 34028587 PMCID: PMC8164623 DOI: 10.1007/s00424-021-02582-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 12/03/2022]
Abstract
We discovered high Na+ and water content in the skin of newborn Sprague–Dawley rats, which reduced ~ 2.5-fold by 7 days of age, indicating rapid changes in extracellular volume (ECV). Equivalent changes in ECV post birth were also observed in C57Bl/6 J mice, with a fourfold reduction over 7 days, to approximately adult levels. This established the generality of increased ECV at birth. We investigated early sodium and water handling in neonates from a second rat strain, Fischer, and an Hsd11b2-knockout rat modelling the syndrome of apparent mineralocorticoid excess (SAME). Despite Hsd11b2−/− animals exhibiting lower skin Na+ and water levels than controls at birth, they retained ~ 30% higher Na+ content in their pelts at the expense of K+ thereafter. Hsd11b2−/− neonates exhibited incipient hypokalaemia from 15 days of age and became increasingly polydipsic and polyuric from weaning. As with adults, they excreted a high proportion of ingested Na+ through the kidney, (56.15 ± 8.21% versus control 34.15 ± 8.23%; n = 4; P < 0.0001), suggesting that changes in nephron electrolyte transporters identified in adults, by RNA-seq analysis, occur by 4 weeks of age. Our data reveal that Na+ imbalance in the Hsd11b2−/− neonate leads to excess Na+ storage in skin and incipient hypokalaemia, which, together with increased, glucocorticoid-induced Na+ uptake in the kidney, then contribute to progressive, volume contracted, salt-sensitive hypertension. Skin Na+ plays an important role in the development of SAME but, equally, may play a key physiological role at birth, supporting post-natal growth, as an innate barrier to infection or as a rudimentary kidney.
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Affiliation(s)
- Linda Mullins
- Molecular Physiology Laboratory, BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.
| | - Jessica Ivy
- Molecular Physiology Laboratory, BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Mairi Ward
- Molecular Physiology Laboratory, BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Olav Tenstad
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Helge Wiig
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Kento Kitada
- Department of Pharmacology, Kagawa University, Takamatsu, Japan
| | - Jon Manning
- EMBL-EBI, Wellcome Genome Campus, Hinxton, UK
| | - Natalia Rakova
- Experimental and Clinical Research Center, a joint cooperation of Max Delbrück Center for Molecular Medicine and Charité-Universitäts-Medizin Berlin, Berlin, Germany
| | - Dominik Muller
- Experimental and Clinical Research Center, a joint cooperation of Max Delbrück Center for Molecular Medicine and Charité-Universitäts-Medizin Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - John Mullins
- Molecular Physiology Laboratory, BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
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Zajac M, Dreano E, Edwards A, Planelles G, Sermet-Gaudelus I. Airway Surface Liquid pH Regulation in Airway Epithelium Current Understandings and Gaps in Knowledge. Int J Mol Sci 2021; 22:3384. [PMID: 33806154 PMCID: PMC8037888 DOI: 10.3390/ijms22073384] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/08/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022] Open
Abstract
Knowledge on the mechanisms of acid and base secretion in airways has progressed recently. The aim of this review is to summarize the known mechanisms of airway surface liquid (ASL) pH regulation and their implication in lung diseases. Normal ASL is slightly acidic relative to the interstitium, and defects in ASL pH regulation are associated with various respiratory diseases, such as cystic fibrosis. Basolateral bicarbonate (HCO3-) entry occurs via the electrogenic, coupled transport of sodium (Na+) and HCO3-, and, together with carbonic anhydrase enzymatic activity, provides HCO3- for apical secretion. The latter mainly involves CFTR, the apical chloride/bicarbonate exchanger pendrin and paracellular transport. Proton (H+) secretion into ASL is crucial to maintain its relative acidity compared to the blood. This is enabled by H+ apical secretion, mainly involving H+/K+ ATPase and vacuolar H+-ATPase that carry H+ against the electrochemical potential gradient. Paracellular HCO3- transport, the direction of which depends on the ASL pH value, acts as an ASL protective buffering mechanism. How the transepithelial transport of H+ and HCO3- is coordinated to tightly regulate ASL pH remains poorly understood, and should be the focus of new studies.
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Affiliation(s)
- Miroslaw Zajac
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences, 02-776 Warsaw, Poland;
| | - Elise Dreano
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
| | - Aurelie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA;
| | - Gabrielle Planelles
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Laboratoire de Physiologie rénale et Tubulopathies, CNRS ERL 8228, 75006 Paris, France
| | - Isabelle Sermet-Gaudelus
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Centre de Référence Maladies Rares, Mucoviscidose et Maladies de CFTR, Hôpital Necker Enfants Malades, 75015 Paris, France
- Clinical Trial Network, European Cystic Fibrosis Society, BT2 Belfast, Ireland
- European Respiratory Network Lung, 75006 Paris, France
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11
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Ayasse N, Berg P, Andersen JF, Svendsen SL, Sørensen MV, Fedosova NU, Lynch IJ, Wingo CS, Leipziger J. Benzamil-mediated urine alkalization is caused by the inhibition of H +-K +-ATPases. Am J Physiol Renal Physiol 2021; 320:F596-F607. [PMID: 33554781 DOI: 10.1152/ajprenal.00444.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Epithelial Na+ channel (ENaC) blockers elicit acute and substantial increases of urinary pH. The underlying mechanism remains to be understood. Here, we evaluated if benzamil-induced urine alkalization is mediated by an acute reduction in H+ secretion via renal H+-K+-ATPases (HKAs). Experiments were performed in vivo on HKA double-knockout and wild-type mice. Alterations in dietary K+ intake were used to change renal HKA and ENaC activity. The acute effects of benzamil (0.2 µg/g body wt, sufficient to block ENaC) on urine flow rate and urinary electrolyte and acid excretion were monitored in anesthetized, bladder-catheterized animals. We observed that benzamil acutely increased urinary pH (ΔpH: 0.33 ± 0.07) and reduced NH4+ and titratable acid excretion and that these effects were distinctly enhanced in animals fed a low-K+ diet (ΔpH: 0.74 ± 0.12), a condition when ENaC activity is low. In contrast, benzamil did not affect urine acid excretion in animals kept on a high-K+ diet (i.e., during high ENaC activity). Thus, urine alkalization appeared completely uncoupled from ENaC function. The absence of benzamil-induced urinary alkalization in HKA double-knockout mice confirmed the direct involvement of these enzymes. The inhibitory effect of benzamil was also shown in vitro for the pig α1-isoform of HKA. These results suggest a revised explanation of the benzamil effect on renal acid-base excretion. Considering the conditions used here, we suggest that it is caused by a direct inhibition of HKAs in the collecting duct and not by inhibition of the ENaC function.NEW & NOTEWORTHY Bolus application of epithelial Na+ channel (EnaC) blockers causes marked and acute increases of urine pH. Here, we provide evidence that the underlying mechanism involves direct inhibition of the H+-K+ pump in the collecting duct. This could provide a fundamental revision of the previously assumed mechanism that suggested a key role of ENaC inhibition in this response.
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Affiliation(s)
- Niklas Ayasse
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | - Peder Berg
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | | | | | - Mads V Sørensen
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | - Natalya U Fedosova
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | - I Jeanette Lynch
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida, Gainesville, Florida.,North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Charles S Wingo
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida, Gainesville, Florida.,North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Jens Leipziger
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
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12
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Increased colonic K + excretion through inhibition of the H,K-ATPase type 2 helps reduce plasma K + level in a murine model of nephronic reduction. Sci Rep 2021; 11:1833. [PMID: 33469051 PMCID: PMC7815745 DOI: 10.1038/s41598-021-81388-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 12/21/2020] [Indexed: 11/09/2022] Open
Abstract
Hyperkalemia is frequently observed in patients at the end-stage of chronic kidney disease (CKD), and has possible harmful consequences on cardiac function. Many strategies are currently used to manage hyperkalemia, one consisting of increasing fecal K+ excretion through the administration of cation-exchange resins. In this study, we explored another more specific method of increasing intestinal K+ secretion by inhibiting the H,K-ATPase type 2 (HKA2), which is the main colonic K+ reabsorptive pathway. We hypothetised that the absence of this pump could impede the increase of plasma K+ levels following nephronic reduction (N5/6) by favoring fecal K+ secretion. In N5/6 WT and HKA2KO mice under normal K+ intake, the plasma K+ level remained within the normal range, however, a load of K+ induced strong hyperkalemia in N5/6 WT mice (9.1 ± 0.5 mM), which was significantly less pronounced in N5/6 HKA2KO mice (7.9 ± 0.4 mM, p < 0.01). This was correlated to a higher capacity of HKA2KO mice to excrete K+ in their feces. The absence of HKA2 also increased fecal Na+ excretion by inhibiting its colonic ENaC-dependent absorption. We also showed that angiotensin-converting-enzyme inhibitor like enalapril, used to treat hypertension during CKD, induced a less severe hyperkalemia in N5/6 HKA2KO than in N5/6 WT mice. This study therefore provides the proof of concept that the targeted inhibition of HKA2 could be a specific therapeutic maneuver to reduce plasma K+ levels in CKD patients.
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13
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Zhang Z, Bao YY, Zhou SH. Pump Proton and Laryngeal H +/K + ATPases. Int J Gen Med 2020; 13:1509-1514. [PMID: 33363399 PMCID: PMC7754099 DOI: 10.2147/ijgm.s284952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/20/2020] [Indexed: 12/14/2022] Open
Abstract
Purpose The presence of extra-gastric H+/K+ ATPases may explain the clinically significant effect of proton pump inhibitor (PPI) pharmacotherapy in patients with chronic laryngitis related to laryngopharyngeal reflux disease (LPRD) but without gastroesophageal reflux disease (GERD) symptoms. Given the need for a better understanding of GERD and LPRD, we review the various proton pumps with respect to their classification, function, and distribution. We then consider the potential role of the laryngeal H+/K+ ATPase pump in LPRD. Methods We searched databases of PubMed, EMBASE, and Web of Science to achieve related published before September 15, 2020. Results There were only seven English-literatures meeting inclusive criteria about laryngeal H+/K+ ATPases. Some studies provide convincing evidence of a laryngeal H+/K+ ATPase in normal laryngeal tissues but also suggest the potential role of the proton pump in the abnormal mucus secretion frequently seen in patients with chronic laryngitis. Conclusion A laryngeal H+/K+ ATPase expresses in normal laryngeal tissues. These findings question the current understanding of GERD and LPRD.
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Affiliation(s)
- Zhe Zhang
- Department of Otolaryngology, Peoples Hospital of Yuyao City, Yuyao 315400, Zhejiang, People's Republic of China
| | - Yang-Yang Bao
- Department of Otolaryngology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People's Republic of China
| | - Shui-Hong Zhou
- Department of Otolaryngology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People's Republic of China
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14
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Wen JJ, Cummins CB, Williams TP, Radhakrishnan RS. The Genetic Evidence of Burn-Induced Cardiac Mitochondrial Metabolism Dysfunction. Biomedicines 2020; 8:biomedicines8120566. [PMID: 33287280 PMCID: PMC7761708 DOI: 10.3390/biomedicines8120566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/27/2020] [Accepted: 12/01/2020] [Indexed: 12/14/2022] Open
Abstract
Burn-induced cardiac dysfunction is thought to involve mitochondrial dysfunction, although the mechanisms responsible are unclear. In this study, we used our established model of in vivo burn injury to understand the genetic evidence of burn-induced mitochondrial confusion dysfunction by describing cardiac mitochondrial metabolism-related gene expression after burn. Cardiac tissue was collected at 24 hours after burn injury. An O2K respirometer system was utilized to measure the cardiac mitochondrial function. Oxidative phosphorylation complex activities were determined using enzyme activity assays. RT Profiler PCR array was used to identify the differential regulation of genes involved in mitochondrial biogenesis and metabolism. The quantitative qPCR and Western blotting were applied to validate the differentially expressed genes. Burn-induced cardiac mitochondrial dysfunction was supported by the finding of decreased state 3 respiration, decreased mitochondrial electron transport chain activity in complex I, III, IV, and V, and decreased mitochondrial DNA-encoded gene expression as well as decreased levels of the corresponding proteins after burn injury. Eighty-four mitochondrial metabolism-related gene profiles were measured. The mitochondrial gene profile showed that 29 genes related to mitochondrial energy and metabolism was differentially expressed. Of these 29 genes, 16 were more than 2-fold upregulated and 13 were more than 2-fold downregulated. All genes were validated using qPCR and partial genes were correlated with their protein levels. This study provides preliminary evidence that a large percentage of mitochondrial metabolism-related genes in cardiomyocytes were significantly affected by burn injury.
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Affiliation(s)
- Jake J. Wen
- Correspondence: (J.J.W.); (R.S.R.); Tel.: +1-409-772-5666 (J.J.W. & R.S.R.)
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15
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Baratta VM, Norz V, Barahona MJ, Gisinger TM, Mulligan D, Geibel JP. Penicillin G Induces H+, K+-ATPase via a Nitric Oxide-Dependent Mechanism in the Rat Colonic Crypt. Cell Physiol Biochem 2020; 54:1132-1142. [PMID: 33175479 PMCID: PMC8095381 DOI: 10.33594/000000305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2020] [Indexed: 11/21/2022] Open
Abstract
Background/Aims: The colonic H+, K+ ATPase (HKA2) is a heterodimeric membrane protein that exchanges luminal K+ for intracellular H+ and is involved in maintaining potassium homeostasis. Under homeostatic conditions, the colonic HKA2 remains inactive, since most of the potassium is absorbed by the small intestine. In diarrheal states, potassium is secreted and compensatory potassium absorption becomes necessary. This study proposes a novel mechanism whereby the addition of penicillin G sodium salt (penG) to colonic crypts stimulates potassium uptake in the presence of intracellular nitric oxide (NO), under sodium-free (0-Na+) conditions. Methods: Sprague Dawley rat colonic crypts were isolated and pHi changes were monitored through the ammonium prepulse technique. Increased proton extrusion in 0-Na+ conditions reflected heightened H+, K+ ATPase activity. Colonic crypts were exposed to penG, L-arginine (a NO precursor), and N-nitro l-arginine methyl ester (L-NAME, a NO synthase inhibitor). Results: Isolated administration of penG significantly increased H+, K+ ATPase activity from baseline, p 0.0067. Co-administration of arginine and penG in 0-Na+ conditions further upregulated H+, K+ ATPase activity, p <0.0001. Crypt perfusion with L-NAME and penG demonstrated a significant reduction in H+, K+ ATPase activity, p 0.0058. Conclusion: Overall, acute exposure of colonic crypts to penG activates the H+, K+ ATPase in the presence of NO. This study provides new insights into colonic potassium homeostasis.
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Affiliation(s)
- Vanessa M Baratta
- Yale University, School of Medicine, Department of Surgery, New Haven, CT, USA
| | - Valentina Norz
- Yale University, School of Medicine, Department of Surgery, New Haven, CT, USA.,Paracelsus Medical University, School of Medicine, Salzburg, Austria
| | - Maria J Barahona
- Yale University, School of Medicine, Department of Surgery, New Haven, CT, USA
| | - Teresa M Gisinger
- Yale University, School of Medicine, Department of Surgery, New Haven, CT, USA.,Paracelsus Medical University, School of Medicine, Salzburg, Austria
| | - David Mulligan
- Yale University, School of Medicine, Department of Surgery, New Haven, CT, USA
| | - John P Geibel
- Yale University, School of Medicine, Department of Surgery, New Haven, CT, USA, .,Yale University School of Medicine, Department of Cellular and Molecular Physiology, New Haven, CT, USA
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16
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Blanchard A, Brailly Tabard S, Lamaziere A, Bergerot D, Zhygalina V, Lorthioir A, Jacques A, Hourton D, Azizi M, Crambert G. Adrenal adaptation in potassium-depleted men: role of progesterone? Nephrol Dial Transplant 2020; 35:1901-1908. [PMID: 31369102 DOI: 10.1093/ndt/gfz135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 05/30/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND In rodents, the stimulation of adrenal progesterone is necessary for renal adaptation under potassium depletion. Here, we sought to determine the role of progesterone in adrenal adaptation in potassium-depleted healthy human volunteers and compared our findings with data collected in patients with Gitelman syndrome (GS), a salt-losing tubulopathy. METHODS Twelve healthy young men were given a potassium-depleted diet for 7 days at a tertiary referral medical centre (NCT02297048). We measured by liquid chromatography coupled to tandem mass spectroscopy plasma steroid concentrations at Days 0 and 7 before and 30 min after treatment with tetracosactide. We compared these data with data collected in 10 GS patients submitted to tetracosactide test. RESULTS The potassium-depleted diet decreased plasma potassium in healthy subjects by 0.3 ± 0.1 mmol/L, decreased plasma aldosterone concentration by 50% (P = 0.0332) and increased plasma 17-hydroxypregnenolone concentration by 45% (P = 0.0232) without affecting other steroids. CYP17 activity, as assessed by 17-hydroxypregnenolone/pregnenolone ratio, increased by 60% (P = 0.0389). As compared with healthy subjects, GS patients had 3-fold higher plasma concentrations of aldosterone, 11-deoxycortisol (+30%) and delta 4-androstenedione (+14%). Their post-tetracosactide progesterone concentration was 2-fold higher than that of healthy subjects and better correlated to plasma potassium than to plasma renin. CONCLUSION The increase in 17-hydroxypregnenolone concentration after mild potassium depletion in otherwise healthy human subjects suggests that 17 hydroxylation of pregnenolone prevents the increase in progesterone observed in potassium-depleted mice. The unexpected over-response of non-mineralocorticoid steroids to tetracosactide in GS subjects suggests that the adrenal system not only adapts to sodium depletion but may also respond to hypokalaemia.
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Affiliation(s)
- Anne Blanchard
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Centre d'Investigation Clinique, Paris, France.,INSERM, CIC-1418, Paris, France
| | - Sylvie Brailly Tabard
- Faculté de Médecine Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Assistance Publique Hôpitaux de Paris, Hôpital de Bicêtre, Service de Génétique Moléculaire, Pharmacogénétique et Hormonologie, Le Kremlin-Bicêtre, France.,Inserm 1185 Faculté de Médecine Paris-Sud, Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Antonin Lamaziere
- Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Plateforme de Métabolomique, Peptidomique et de Dosage de Médicaments, Paris, France.,INSERM ERL1157, Le Kremlin-Bicêtre, France
| | | | - Valentina Zhygalina
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Centre d'Investigation Clinique, Paris, France.,INSERM, CIC-1418, Paris, France
| | - Aurélien Lorthioir
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Centre d'Investigation Clinique, Paris, France.,INSERM, CIC-1418, Paris, France
| | - Antoine Jacques
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Unité de recherche clinique, Paris, France
| | - Delphine Hourton
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Unité de recherche clinique, Paris, France
| | - Michel Azizi
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Centre d'Investigation Clinique, Paris, France.,INSERM, CIC-1418, Paris, France
| | - Gilles Crambert
- Sorbonne Université, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France.,CNRS ERL 8228-Centre de Recherche des Cordeliers-Laboratoire de Physiologie Rénale et tubulopathies, Paris, France
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17
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Walter C, Rafael C, Lasaad S, Baron S, Salhi A, Crambert G. H,K-ATPase type 2 regulates gestational extracellular compartment expansion and blood pressure in mice. Am J Physiol Regul Integr Comp Physiol 2020; 318:R320-R328. [PMID: 31913688 DOI: 10.1152/ajpregu.00067.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The modifications of the hemodynamic system and hydromineral metabolism are physiological features characterizing a normal gestation. Thus, the ability to expand plasma volume without increasing the level of blood pressure is necessary for the correct perfusion of the placenta. The kidney is essential in this adaptation by reabsorbing avidly sodium and fluid. In this study, we observed that the H,K-ATPase type 2 (HKA2), an ion pump expressed in kidney and colon and already involved in the control of the K+ balance during gestation, is also required for the correct plasma volume expansion and to maintain normal blood pressure. Indeed, compared with WT pregnant mice that exhibit a 1.6-fold increase of their plasma volume, pregnant HKA2-null mice (HKA2KO) only modestly expand their extracellular volume (×1.2). The renal expression of the epithelial Na channel (ENaC) α- and γ-subunits and that of the pendrin are stimulated in gravid WT mice, whereas the Na/Cl- cotransporter (NCC) expression is downregulated. These modifications are all blunted in HKA2KO mice. This impeded renal adaptation to gestation is accompanied by the development of hypotension in the pregnant HKA2KO mice. Altogether, our results showed that the absence of the HKA2 during gestation leads to an "underfilled" situation and has established this transporter as a key player of the renal control of salt and potassium metabolism during gestation.
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Affiliation(s)
- Christine Walter
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Sorbonne Paris Cité Université, Université Paris Descartes, Université Paris Diderot, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Chloé Rafael
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Sorbonne Paris Cité Université, Université Paris Descartes, Université Paris Diderot, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Samia Lasaad
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Sorbonne Paris Cité Université, Université Paris Descartes, Université Paris Diderot, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Stéphanie Baron
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Sorbonne Paris Cité Université, Université Paris Descartes, Université Paris Diderot, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France.,Hôpital Européen Georges Pompidou, Laboratoire de Physiologie, Paris, France
| | - Amel Salhi
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Sorbonne Paris Cité Université, Université Paris Descartes, Université Paris Diderot, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Gilles Crambert
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Sorbonne Paris Cité Université, Université Paris Descartes, Université Paris Diderot, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
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18
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Keppner A, Maric D, Sergi C, Ansermet C, De Bellis D, Kratschmar DV, Canonica J, Klusonova P, Fenton RA, Odermatt A, Crambert G, Hoogewijs D, Hummler E. Deletion of the serine protease CAP2/Tmprss4 leads to dysregulated renal water handling upon dietary potassium depletion. Sci Rep 2019; 9:19540. [PMID: 31863073 PMCID: PMC6925205 DOI: 10.1038/s41598-019-55995-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/04/2019] [Indexed: 01/09/2023] Open
Abstract
The kidney needs to adapt daily to variable dietary K+ contents via various mechanisms including diuretic, acid-base and hormonal changes that are still not fully understood. In this study, we demonstrate that following a K+-deficient diet in wildtype mice, the serine protease CAP2/Tmprss4 is upregulated in connecting tubule and cortical collecting duct and also localizes to the medulla and transitional epithelium of the papilla and minor calyx. Male CAP2/Tmprss4 knockout mice display altered water handling and urine osmolality, enhanced vasopressin response leading to upregulated adenylate cyclase 6 expression and cAMP overproduction, and subsequently greater aquaporin 2 (AQP2) and Na+-K+-2Cl− cotransporter 2 (NKCC2) expression following K+-deficient diet. Urinary acidification coincides with significantly increased H+,K+-ATPase type 2 (HKA2) mRNA and protein expression, and decreased calcium and phosphate excretion. This is accompanied by increased glucocorticoid receptor (GR) protein levels and reduced 11β-hydroxysteroid dehydrogenase 2 activity in knockout mice. Strikingly, genetic nephron-specific deletion of GR leads to the mirrored phenotype of CAP2/Tmprss4 knockouts, including increased water intake and urine output, urinary alkalinisation, downregulation of HKA2, AQP2 and NKCC2. Collectively, our data unveil a novel role of the serine protease CAP2/Tmprss4 and GR on renal water handling upon dietary K+ depletion.
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Affiliation(s)
- Anna Keppner
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland
| | - Darko Maric
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland
| | - Chloé Sergi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Camille Ansermet
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Damien De Bellis
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland.,Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland
| | - Denise V Kratschmar
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland
| | - Jérémie Canonica
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland.,Ophthalmic Hospital Jules Gonin, University of Lausanne, Lausanne, Switzerland
| | - Petra Klusonova
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Alex Odermatt
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland
| | | | - David Hoogewijs
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland. .,National Center of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH), University of Lausanne, Lausanne, Switzerland.
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19
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Crambert G, Rafael C, Doucet A, Cheval L, Walter C. Proliferation of renal intercalated cells type A after dietary K restriction involves GDF15 and the stimulation of the H,K‐ATPase type 2. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.862.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gilles Crambert
- Renal Physiology and TubulopathiesCentre de Recherche des Cordeliers ‐ INSERM U1138 ‐ CNRS ERL8228ParisFrance
| | - Chloé Rafael
- Renal Physiology and TubulopathiesCentre de Recherche des Cordeliers ‐ INSERM U1138 ‐ CNRS ERL8228ParisFrance
| | - Alain Doucet
- Renal Physiology and TubulopathiesCentre de Recherche des Cordeliers ‐ INSERM U1138 ‐ CNRS ERL8228ParisFrance
| | - Lydie Cheval
- Renal Physiology and TubulopathiesCentre de Recherche des Cordeliers ‐ INSERM U1138 ‐ CNRS ERL8228ParisFrance
| | - Christine Walter
- Renal Physiology and TubulopathiesCentre de Recherche des Cordeliers ‐ INSERM U1138 ‐ CNRS ERL8228ParisFrance
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20
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Bissler JJ, Zadjali F, Bridges D, Astrinidis A, Barone S, Yao Y, Redd JR, Siroky BJ, Wang Y, Finley JT, Rusiniak ME, Baumann H, Zahedi K, Gross KW, Soleimani M. Tuberous sclerosis complex exhibits a new renal cystogenic mechanism. Physiol Rep 2019; 7:e13983. [PMID: 30675765 PMCID: PMC6344348 DOI: 10.14814/phy2.13983] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 12/20/2018] [Indexed: 02/06/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a tumor predisposition syndrome with significant renal cystic and solid tumor disease. While the most common renal tumor in TSC, the angiomyolipoma, exhibits a loss of heterozygosity associated with disease, we have discovered that the renal cystic epithelium is composed of type A intercalated cells that have an intact Tsc gene that have been induced to exhibit Tsc-mutant disease phenotype. This mechanism appears to be different than that for ADPKD. The murine models described here closely resemble the human disease and both appear to be mTORC1 inhibitor responsive. The induction signaling driving cystogenesis may be mediated by extracellular vesicle trafficking.
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Affiliation(s)
- John J. Bissler
- Department of PediatricsUniversity of Tennessee Health Science Center and Le Bonheur Children's HospitalMemphisTennessee
- St. Jude Children's Research HospitalMemphisTennessee
| | - Fahad Zadjali
- Department of Clinical BiochemistryCollege of Medicine & Health SciencesSultan Qaboos UniversityMuscatOman
| | - Dave Bridges
- Department of Nutritional SciencesUniversity of Michigan School of Public HealthAnn ArborMichigan
| | - Aristotelis Astrinidis
- Department of PediatricsUniversity of Tennessee Health Science Center and Le Bonheur Children's HospitalMemphisTennessee
| | - Sharon Barone
- Departments of MedicineUniversity of Cincinnati College of MedicineCincinnatiOhio
- Center on Genetics of TransportUniversity of Cincinnati College of MedicineCincinnatiOhio
- Research ServicesVeterans Affairs Medical CenterCincinnatiOhio
| | - Ying Yao
- Department of PediatricsUniversity of Tennessee Health Science Center and Le Bonheur Children's HospitalMemphisTennessee
| | - JeAnna R. Redd
- Department of Nutritional SciencesUniversity of Michigan School of Public HealthAnn ArborMichigan
| | - Brian J. Siroky
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhio
| | - Yanqing Wang
- Department of Molecular and Cellular BiologyRoswell Park Cancer InstituteBuffaloNew York
| | - Joel T. Finley
- Department of PediatricsUniversity of Tennessee Health Science Center and Le Bonheur Children's HospitalMemphisTennessee
| | - Michael E. Rusiniak
- Department of Molecular and Cellular BiologyRoswell Park Cancer InstituteBuffaloNew York
| | - Heinz Baumann
- Department of Molecular and Cellular BiologyRoswell Park Cancer InstituteBuffaloNew York
| | - Kamyar Zahedi
- Departments of MedicineUniversity of Cincinnati College of MedicineCincinnatiOhio
- Center on Genetics of TransportUniversity of Cincinnati College of MedicineCincinnatiOhio
- Research ServicesVeterans Affairs Medical CenterCincinnatiOhio
| | - Kenneth W. Gross
- Department of Molecular and Cellular BiologyRoswell Park Cancer InstituteBuffaloNew York
| | - Manoocher Soleimani
- Departments of MedicineUniversity of Cincinnati College of MedicineCincinnatiOhio
- Center on Genetics of TransportUniversity of Cincinnati College of MedicineCincinnatiOhio
- Research ServicesVeterans Affairs Medical CenterCincinnatiOhio
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21
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Kamel KS, Schreiber M, Halperin ML. Renal potassium physiology: integration of the renal response to dietary potassium depletion. Kidney Int 2018; 93:41-53. [PMID: 29102372 DOI: 10.1016/j.kint.2017.08.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/31/2017] [Accepted: 08/03/2017] [Indexed: 01/30/2023]
Abstract
We summarize the current understanding of the physiology of the renal handling of potassium (K+), and present an integrative view of the renal response to K+ depletion caused by dietary K+ restriction. This renal response involves contributions from different nephron segments, and aims to diminish the rate of excretion of K+ as a result of: decreasing the rate of electrogenic (and increasing the rate of electroneutral) reabsorption of sodium in the aldosterone-sensitive distal nephron (ASDN), decreasing the abundance of renal outer medullary K+ channels in the luminal membrane of principal cells in the ASDN, decreasing the flow rate in the ASDN, and increasing the reabsorption of K+ in the cortical and medullary collecting ducts. The implications of this physiology for the association between K+ depletion and hypertension, and K+ depletion and formation of calcium kidney stones are discussed.
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Affiliation(s)
- Kamel S Kamel
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
| | - Martin Schreiber
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Mitchell L Halperin
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
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22
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Scudieri P, Musante I, Caci E, Venturini A, Morelli P, Walter C, Tosi D, Palleschi A, Martin-Vasallo P, Sermet-Gaudelus I, Planelles G, Crambert G, Galietta LJ. Increased expression of ATP12A proton pump in cystic fibrosis airways. JCI Insight 2018; 3:123616. [PMID: 30333310 DOI: 10.1172/jci.insight.123616] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/29/2018] [Indexed: 11/17/2022] Open
Abstract
Proton secretion mediated by ATP12A protein on the surface of the airway epithelium may contribute to cystic fibrosis (CF) lung disease by favoring bacterial infection and airway obstruction. We studied ATP12A in fresh bronchial samples and in cultured epithelial cells. In vivo, ATP12A expression was found almost exclusively at the apical side of nonciliated cells of airway epithelium and in submucosal glands, with much higher expression in CF samples. This could be due to bacterial infection and inflammation, since treating cultured cells with bacterial supernatants or with IL-4 (a cytokine that induces goblet cell hyperplasia) increased the expression of ATP12A in nonciliated cells. This observation was associated with upregulation and translocation of ATP1B1 protein from the basal to apical epithelial side, where it colocalizes with ATP12A. ATP12A function was evaluated by measuring the pH of the apical fluid in cultured epithelia. Under resting conditions, CF epithelia showed more acidic values. This abnormality was minimized by inhibiting ATP12A with ouabain. Following treatment with IL-4, ATP12A function was markedly increased, as indicated by strong acidification occurring under bicarbonate-free conditions. Our study reveals potentially novel aspects of ATP12A and remarks its importance as a possible therapeutic target in CF and other respiratory diseases.
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Affiliation(s)
- Paolo Scudieri
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli NA, Italy
| | - Ilaria Musante
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli NA, Italy
| | - Emanuela Caci
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | - Arianna Venturini
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli NA, Italy
| | - Patrizia Morelli
- U.O.C. Laboratorio Analisi, Istituto Giannina Gaslini, Genova, Italy
| | - Christine Walter
- CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, Paris, France.,Sorbonne Université, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France
| | - Davide Tosi
- Thoracic Surgery and Lung Transplantation Unit, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, Milano, Italy
| | - Alessandro Palleschi
- Thoracic Surgery and Lung Transplantation Unit, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, Milano, Italy
| | - Pablo Martin-Vasallo
- UD de Bioquímica y Biología Molecular and Centro de Investigaciones Biomédicas de Canarias (CIBICAN), Universidad de La Laguna, La Laguna, Tenerife, Spain
| | | | - Gabrielle Planelles
- CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, Paris, France.,Sorbonne Université, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France
| | - Gilles Crambert
- CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, Paris, France.,Sorbonne Université, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France
| | - Luis Jv Galietta
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli NA, Italy
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23
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Al-Qusairi L, Basquin D, Roy A, Rajaram RD, Maillard MP, Subramanya AR, Staub O. Renal Tubular Ubiquitin-Protein Ligase NEDD4-2 Is Required for Renal Adaptation during Long-Term Potassium Depletion. J Am Soc Nephrol 2017; 28:2431-2442. [PMID: 28289184 DOI: 10.1681/asn.2016070732] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 02/01/2017] [Indexed: 11/03/2022] Open
Abstract
Adaptation of the organism to potassium (K+) deficiency requires precise coordination among organs involved in K+ homeostasis, including muscle, liver, and kidney. How the latter performs functional and molecular changes to ensure K+ retention is not well understood. Here, we investigated the role of ubiquitin-protein ligase NEDD4-2, which negatively regulates the epithelial sodium channel (ENaC), Na+/Cl- cotransporter (NCC), and with no-lysine-kinase 1 (WNK1). After dietary K+ restriction for 2 weeks, compared with control littermates, inducible renal tubular NEDD4-2 knockout (Nedd4LPax8/LC1 ) mice exhibited severe hypokalemia and urinary K+ wasting. Notably, expression of the ROMK K+ channel did not change in the distal convoluted tubule and decreased slightly in the cortical/medullary collecting duct, whereas BK channel abundance increased in principal cells of the connecting tubule/collecting ducts. However, K+ restriction also enhanced ENaC expression in Nedd4LPax8/LC1 mice, and treatment with the ENaC inhibitor, benzamil, reversed excessive K+ wasting. Moreover, K+ restriction increased WNK1 and WNK4 expression and enhanced SPAK-mediated NCC phosphorylation in Nedd4LPax8/LC1 mice, with no change in total NCC. We propose a mechanism in which NEDD4-2 deficiency exacerbates hypokalemia during dietary K+ restriction primarily through direct upregulation of ENaC, whereas increased BK channel expression has a less significant role. These changes outweigh the compensatory antikaliuretic effects of diminished ROMK expression, increased NCC phosphorylation, and enhanced WNK pathway activity in the distal convoluted tubule. Thus, NEDD4-2 has a crucial role in K+ conservation through direct and indirect effects on ENaC, distal nephron K+ channels, and WNK signaling.
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Affiliation(s)
- Lama Al-Qusairi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
| | - Denis Basquin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
| | - Ankita Roy
- Department of Medicine, University of Pittsburgh School of Medicine and VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania; and
| | - Renuga Devi Rajaram
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
| | - Marc P Maillard
- Service of Nephrology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh School of Medicine and VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania; and
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; .,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
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24
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McDonough AA, Youn JH. Potassium Homeostasis: The Knowns, the Unknowns, and the Health Benefits. Physiology (Bethesda) 2017; 32:100-111. [PMID: 28202621 PMCID: PMC5337831 DOI: 10.1152/physiol.00022.2016] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Potassium homeostasis has a very high priority because of its importance for membrane potential. Although extracellular K+ is only 2% of total body K+, our physiology was evolutionarily tuned for a high-K+, low-Na+ diet. We review how multiple systems interface to accomplish fine K+ balance and the consequences for health and disease.
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Affiliation(s)
- Alicia A McDonough
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Jang H Youn
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
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25
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Ruiz-Jarabo I, Barany A, Jerez-Cepa I, Mancera JM, Fuentes J. Intestinal response to salinity challenge in the Senegalese sole (Solea senegalensis). Comp Biochem Physiol A Mol Integr Physiol 2016; 204:57-64. [PMID: 27865855 DOI: 10.1016/j.cbpa.2016.11.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 09/08/2016] [Accepted: 11/14/2016] [Indexed: 12/27/2022]
Abstract
Fish are continuously forced to actively absorb or expel water and ions through epithelia. Most studies have focused on the gill due to its role in Na+ and Cl- trafficking. However, comparatively few studies have focused on the changing function of the intestine in response to external salinity. Therefore, the present study investigated the main intestinal changes of long-term acclimation of the Senegalese sole (Solea senegalensis) to 5, 15, 38 and 55ppt. Through the measurement of short-circuit current (Isc) in Ussing chambers and biochemical approaches, we described a clear anterior/posterior functional regionalization of the intestine in response to salinity. The use of specific inhibitors in Ussing chamber experiments, revealed that the bumetanide-sensitive Na+/K+/Cl- co-transporters are the main effectors of Cl- uptake in both anterior intestine and rectum. Additionally, the use of the anion exchanger specific inhibitor, DIDS, showed a salinity/region dependency of anion exchanger function. Moreover, we also described ouabain-sensitive Na+/K+-ATPase (NKA) and Bafilomycin A1-sensitive H+-ATPase activities (HA), which displayed changes related to salinity and intestinal region. However, the most striking result of the present study is the description of an omeprazole-sensitive H+/K+-ATPase (HKA) in the rectum of Senegalese sole. Its activity was consistently measurable and increased at lower salinities, reaching rates even higher than those of the NKA. Together our results provide new insights into the changing role of the intestine in response to external salinity in teleost fish. The rectal activity of HKA offers an alternative/cooperative mechanism with the HA in the final processing of intestinal water absorption by apical titration of secreted bicarbonate.
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Affiliation(s)
- I Ruiz-Jarabo
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - A Barany
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - I Jerez-Cepa
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - J M Mancera
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - J Fuentes
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
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26
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Morla L, Doucet A, Lamouroux C, Crambert G, Edwards A. The renal cortical collecting duct: a secreting epithelium? J Physiol 2016; 594:5991-6008. [PMID: 27412964 PMCID: PMC5063930 DOI: 10.1113/jp272877] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/07/2016] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS The cortical collecting duct (CCD) plays an essential role in sodium homeostasis by fine-tuning the amount of sodium that is excreted in the urine. Ex vivo, the microperfused CCD reabsorbs sodium in the absence of lumen-to-bath concentration gradients. In the present study, we show that, in the presence of physiological lumen-to-bath concentration gradients, and in the absence of endocrine, paracrine and neural regulation, the mouse CCD secretes sodium, which represents a paradigm shift. This secretion occurs via the paracellular route, as well as a transcellular pathway that is energized by apical H+ /K+ -ATPase type 2 pumps operating as Na+ /K+ exchangers. The newly identified transcellular secretory pathway represents a physiological target for the regulation of sodium handling and for anti-hypertensive therapeutic agents. ABSTRACT In vitro microperfusion experiments have demonstrated that cortical collecting ducts (CCDs) reabsorb sodium via principal and type B intercalated cells under sodium-depleted conditions and thereby contribute to sodium and blood pressure homeostasis. However, these experiments were performed in the absence of the transepithelial ion concentration gradients that prevail in vivo and determine paracellular transport. The present study aimed to characterize Na+ , K+ and Cl- fluxes in the mouse CCD in the presence of physiological transepithelial concentration gradients. For this purpose, we combined in vitro measurements of ion fluxes across microperfused CCDs of sodium-depleted mice with the predictions of a mathematical model. When NaCl transport was inhibited in all cells, CCDs secreted Na+ and reabsorbed K+ ; Cl- transport was negligible. Removing inhibitors of type A and B intercalated cells increased Na+ secretion in wild-type (WT) mice but not in H+ /K+ -ATPase type 2 (HKA2) knockout mice. Further inhibition of basolateral NaCl entry via the Na+ -K+ -2Cl- cotransporter in type A intercalated cells reduced Na+ secretion in WT mice to the levels observed in HKA2-/- mice. With no inhibitors, WT mouse CCDs still secreted Na+ and reabsorbed K+ . In vivo, HKA2-/- mice excreted less Na+ than WT mice after switching to a high-salt diet. Taken together, our results indicate that type A intercalated cells secrete Na+ via basolateral Na+ -K+ -2Cl- cotransporters in tandem with apical HKA2 pumps. They also suggest that the CCD can mediate overall Na+ secretion, and that its ability to reabsorb NaCl in vivo depends on the presence of acute regulatory factors.
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Affiliation(s)
- Luciana Morla
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, CNRS, ERL 8228, Centre de Recherche des Cordeliers, Paris, France
| | - Alain Doucet
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, CNRS, ERL 8228, Centre de Recherche des Cordeliers, Paris, France
| | - Christine Lamouroux
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, CNRS, ERL 8228, Centre de Recherche des Cordeliers, Paris, France
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27
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Walter C, Tanfous MB, Igoudjil K, Salhi A, Escher G, Crambert G. H,K-ATPase type 2 contributes to salt-sensitive hypertension induced by K(+) restriction. Pflugers Arch 2016; 468:1673-83. [PMID: 27562425 DOI: 10.1007/s00424-016-1872-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 08/15/2016] [Accepted: 08/17/2016] [Indexed: 01/24/2023]
Abstract
In industrialized countries, a large part of the population is daily exposed to low K(+) intake, a situation correlated with the development of salt-sensitive hypertension. Among many processes, adaptation to K(+)-restriction involves the stimulation of H,K-ATPase type 2 (HKA2) in the kidney and colon and, in this study, we have investigated whether HKA2 also contributes to the determination of blood pressure (BP). By using wild-type (WT) and HKA2-null mice (HKA2 KO), we showed that after 4 days of K(+) restriction, WT remain normokalemic and normotensive (112 ± 3 mmHg) whereas HKA2 KO mice exhibit hypokalemia and hypotension (104 ± 2 mmHg). The decrease of BP in HKA2 KO is due to the absence of NaCl-cotransporter (NCC) stimulation, leading to renal loss of salt and decreased extracellular volume (by 20 %). These effects are likely related to the renal resistance to vasopressin observed in HKA2 KO that may be explained, in part by the increased production of prostaglandin E2 (PGE2). In WT, the stimulation of NCC induced by K(+)-restriction is responsible for the elevation in BP when salt intake increases, an effect blunted in HKA2-null mice. The presence of an activated HKA2 is therefore required to limit the decrease in plasma [K(+)] but also contributes to the development of salt-sensitive hypertension.
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Affiliation(s)
- Christine Walter
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France.,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France
| | - Mariem Ben Tanfous
- Faculté des Sciences de Tunis El Manar, Campus Universitaire 2092, El Manar Tunis, Tunisie
| | - Katia Igoudjil
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France.,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France
| | - Amel Salhi
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France.,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France
| | - Geneviève Escher
- Departement für Nephrologie, Hypertonie und klinische Pharmakologie, Universitätsspital Bern - Inselspital, CH-3010, Bern, Switzerland
| | - Gilles Crambert
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France. .,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France.
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28
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Al-Qusairi L, Basquin D, Roy A, Stifanelli M, Rajaram RD, Debonneville A, Nita I, Maillard M, Loffing J, Subramanya AR, Staub O. Renal tubular SGK1 deficiency causes impaired K+ excretion via loss of regulation of NEDD4-2/WNK1 and ENaC. Am J Physiol Renal Physiol 2016; 311:F330-42. [PMID: 27009335 DOI: 10.1152/ajprenal.00002.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 03/21/2016] [Indexed: 11/22/2022] Open
Abstract
The stimulation of postprandial K(+) clearance involves aldosterone-independent and -dependent mechanisms. In this context, serum- and glucocorticoid-induced kinase (SGK)1, a ubiquitously expressed kinase, is one of the primary aldosterone-induced proteins in the aldosterone-sensitive distal nephron. Germline inactivation of SGK1 suggests that this kinase is fundamental for K(+) excretion under conditions of K(+) load, but the specific role of renal SGK1 remains elusive. To avoid compensatory mechanisms that may occur during nephrogenesis, we used inducible, nephron-specific Sgk1(Pax8/LC1) mice to assess the role of renal tubular SGK1 in K(+) regulation. Under a standard diet, these animals exhibited normal K(+) handling. When challenged by a high-K(+) diet, they developed severe hyperkalemia accompanied by a defect in K(+) excretion. Molecular analysis revealed reduced neural precursor cell expressed developmentally downregulated protein (NEDD)4-2 phosphorylation and total expression. γ-Epithelial Na(+) channel (ENaC) expression and α/γENaC proteolytic processing were also decreased in mutant mice. Moreover, with no lysine kinase (WNK)1, which displayed in control mice punctuate staining in the distal convoluted tubule and diffuse distribution in the connecting tubule/cortical colleting duct, was diffused in the distal convoluted tubule and less expressed in the connecting tubule/collecting duct of Sgk(Pax8/LC1) mice. Moreover, Ste20-related proline/alanine-rich kinase phosphorylation, and Na(+)-Cl(-) cotransporter phosphorylation/apical localization were reduced in mutant mice. Consistent with the altered WNK1 expression, increased renal outer medullary K(+) channel apical localization was observed. In conclusion, our data suggest that renal tubular SGK1 is important in the regulation of K(+) excretion via the control of NEDD4-2, WNK1, and ENaC.
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Affiliation(s)
- Lama Al-Qusairi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
| | - Denis Basquin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
| | - Ankita Roy
- Department of Medicine, University of Pittsburgh School of Medicine and Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Matteo Stifanelli
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Renuga Devi Rajaram
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Anne Debonneville
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Izabela Nita
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Marc Maillard
- Service of Nephrology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; and National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
| | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh School of Medicine and Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
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29
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Nadal-Quirós M, Moore LC, Marcano M. Parameter estimation for mathematical models of a nongastric H+(Na+)-K(+)(NH4+)-ATPase. Am J Physiol Renal Physiol 2015; 309:F434-46. [PMID: 26109090 PMCID: PMC4556890 DOI: 10.1152/ajprenal.00539.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 06/18/2015] [Indexed: 11/22/2022] Open
Abstract
The role of nongastric H(+)-K(+)-ATPase (HKA) in ion homeostasis of macula densa (MD) cells is an open question. To begin to explore this issue, we developed two mathematical models that describe ion fluxes through a nongastric HKA. One model assumes a 1H(+):1K(+)-per-ATP stoichiometry; the other assumes a 2H(+):2K(+)-per-ATP stoichiometry. Both models include Na+ and NH4+ competitive binding with H+ and K+, respectively, a characteristic observed in vitro and in situ. Model rate constants were obtained by minimizing the distance between model and experimental outcomes. Both 1H(+)(1Na(+)):1K(+)(1NH4 (+))-per-ATP and 2H(+)(2Na(+)):2K(+)(2NH4 (+))-per-ATP models fit the experimental data well. Using both models, we simulated ion net fluxes as a function of cytosolic or luminal ion concentrations typical for the cortical thick ascending limb and MD region. We observed that (1) K+ and NH4+ flowed in the lumen-to-cytosol direction, (2) there was competitive behavior between luminal K+ and NH4+ and between cytosolic Na+ and H+, 3) ion fluxes were highly sensitive to changes in cytosolic Na+ or H+ concentrations, and 4) the transporter does mostly Na+ / K+ exchange under physiological conditions. These results support the concept that nongastric HKA may contribute to Na+ and pH homeostasis in MD cells. Furthermore, in both models, H+ flux reversed at a luminal pH that was <5.6. Such reversal led to Na+ / H+ exchange for a luminal pH of <2 and 4 in the 1:1-per-ATP and 2:2-per-ATP models, respectively. This suggests a novel role of nongastric HKA in cell Na+ homeostasis in the more acidic regions of the renal tubules.
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Affiliation(s)
| | - Leon C Moore
- Department of Physiology and Biophysics, State University of New York Health Science Center, Stony Brook, New York
| | - Mariano Marcano
- Department of Computer Science, University of Puerto Rico, Río Piedras, Puerto Rico
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Abstract
The H(+) concentration in human blood is kept within very narrow limits, ~40 nmol/L, despite the fact that dietary metabolism generates acid and base loads that are added to the systemic circulation throughout the life of mammals. One of the primary functions of the kidney is to maintain the constancy of systemic acid-base chemistry. The kidney has evolved the capacity to regulate blood acidity by performing three key functions: (i) reabsorb HCO3(-) that is filtered through the glomeruli to prevent its excretion in the urine; (ii) generate a sufficient quantity of new HCO3(-) to compensate for the loss of HCO3(-) resulting from dietary metabolic H(+) loads and loss of HCO3(-) in the urea cycle; and (iii) excrete HCO3(-) (or metabolizable organic anions) following a systemic base load. The ability of the kidney to perform these functions requires that various cell types throughout the nephron respond to changes in acid-base chemistry by modulating specific ion transport and/or metabolic processes in a coordinated fashion such that the urine and renal vein chemistry is altered appropriately. The purpose of the article is to provide the interested reader with a broad review of a field that began historically ~60 years ago with whole animal studies, and has evolved to where we are currently addressing questions related to kidney acid-base regulation at the single protein structure/function level.
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Affiliation(s)
- Ira Kurtz
- Division of Nephrology, David Geffen School of Medicine, Los Angeles, CA; Brain Research Institute, UCLA, Los Angeles, CA
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Penton D, Czogalla J, Loffing J. Dietary potassium and the renal control of salt balance and blood pressure. Pflugers Arch 2015; 467:513-30. [PMID: 25559844 DOI: 10.1007/s00424-014-1673-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 01/09/2023]
Abstract
Dietary potassium (K(+)) intake has antihypertensive effects, prevents strokes, and improves cardiovascular outcomes. The underlying mechanism for these beneficial effects of high K(+) diets may include vasodilation, enhanced urine flow, reduced renal renin release, and negative sodium (Na(+)) balance. Indeed, several studies demonstrate that dietary K(+) intake induces renal Na(+) loss despite elevated plasma aldosterone. This review briefly highlights the epidemiological and experimental evidences for the effects of dietary K(+) on arterial blood pressure. It discusses the pivotal role of the renal distal tubule for the regulation of urinary K(+) and Na(+) excretion and blood pressure and highlights that it depends on the coordinated interaction of different nephron portions, epithelial cell types, and various ion channels, transporters, and ATPases. Moreover, we discuss the relevance of aldosterone and aldosterone-independent factors in mediating the effects of an altered K(+) intake on renal K(+) and Na(+) handling. Particular focus is given to findings suggesting that an aldosterone-independent downregulation of the thiazide-sensitive NaCl cotransporter significantly contributes to the natriuretic and antihypertensive effect of a K(+)-rich diet. Last but not least, we refer to the complex signaling pathways enabling the kidney to adapt its function to the homeostatic needs in response to an altered K(+) intake. Future work will have to further address the underlying cellular and molecular mechanism and to elucidate, among others, how an altered dietary K(+) intake is sensed and how this signal is transmitted to the different epithelial cells lining the distal tubule.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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