1
|
Fan Z, Karakone M, Nagarajan S, Nagy N, Mildenberger W, Petrova E, Hinte LC, Bijnen M, Häne P, Nelius E, Chen J, Ferapontova I, von Meyenn F, Trepiccione F, Berber M, Ribas DP, Eichmann A, Zennaro MC, Takeda N, Fischer JW, Spyroglou A, Reincke M, Beuschlein F, Loffing J, Greter M, Stockmann C. Macrophages preserve endothelial cell specialization in the adrenal gland to modulate aldosterone secretion and blood pressure. Cell Rep 2024; 43:114395. [PMID: 38941187 DOI: 10.1016/j.celrep.2024.114395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/22/2024] [Accepted: 06/07/2024] [Indexed: 06/30/2024] Open
Abstract
Macrophages play crucial roles in organ-specific functions and homeostasis. In the adrenal gland, macrophages closely associate with sinusoidal capillaries in the aldosterone-producing zona glomerulosa. We demonstrate that macrophages preserve capillary specialization and modulate aldosterone secretion. Using macrophage-specific deletion of VEGF-A, single-cell transcriptomics, and functional phenotyping, we found that the loss of VEGF-A depletes PLVAP+ fenestrated endothelial cells in the zona glomerulosa, leading to increased basement membrane collagen IV deposition and subendothelial fibrosis. This results in increased aldosterone secretion, called "haptosecretagogue" signaling. Human aldosterone-producing adenomas also show capillary rarefaction and basement membrane thickening. Mice with myeloid cell-specific VEGF-A deletion exhibit elevated serum aldosterone, hypokalemia, and hypertension, mimicking primary aldosteronism. These findings underscore macrophage-to-endothelial cell signaling as essential for endothelial cell specialization, adrenal gland function, and blood pressure regulation, with broader implications for other endocrine organs.
Collapse
Affiliation(s)
- Zheng Fan
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland.
| | - Mara Karakone
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland
| | | | - Nadine Nagy
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wiebke Mildenberger
- University of Zurich, Institute for Experimental Immunology, 8057 Zurich, Switzerland
| | - Ekaterina Petrova
- University of Zurich, Institute for Experimental Immunology, 8057 Zurich, Switzerland
| | - Laura Catharina Hinte
- Laboratory of Nutrition and Metabolic Epigenetics, Institute for Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Mitchell Bijnen
- University of Zurich, Institute for Experimental Immunology, 8057 Zurich, Switzerland
| | - Philipp Häne
- University of Zurich, Institute for Experimental Immunology, 8057 Zurich, Switzerland
| | - Eric Nelius
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland
| | - Jing Chen
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland
| | - Irina Ferapontova
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland
| | - Ferdinand von Meyenn
- Laboratory of Nutrition and Metabolic Epigenetics, Institute for Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Francesco Trepiccione
- Department of Translational Medical Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Mesut Berber
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland
| | - David Penton Ribas
- Electrophysiology Facility (e-phac), Department of Molecular Life Sciences, University of Zurich (UZH), 8057 Zürich, Switzerland
| | - Anne Eichmann
- Cardiovascular Research Center and Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Norihiko Takeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Jens W Fischer
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Ariadni Spyroglou
- Klinik für Endokrinologie, Diabetologie, und Klinische Ernährung, UniversitätsSpital Zürich (USZ) and UZH, Raemistrasse 100, 8091 Zurich, Switzerland; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Martin Reincke
- Klinik für Endokrinologie, Diabetologie, und Klinische Ernährung, UniversitätsSpital Zürich (USZ) and UZH, Raemistrasse 100, 8091 Zurich, Switzerland
| | - Felix Beuschlein
- Klinik für Endokrinologie, Diabetologie, und Klinische Ernährung, UniversitätsSpital Zürich (USZ) and UZH, Raemistrasse 100, 8091 Zurich, Switzerland; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Johannes Loffing
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland
| | - Melanie Greter
- University of Zurich, Institute for Experimental Immunology, 8057 Zurich, Switzerland
| | - Christian Stockmann
- University of Zurich, Institute of Anatomy, 8057 Zurich, Switzerland; INSERM U970, Paris Cardiovascular Research Center, Paris, France.
| |
Collapse
|
2
|
Küng CJ, Daryadel A, Fuente R, Haykir B, de Angelis MH, Hernando N, Rubio-Aliaga I, Wagner CA. A novel mouse model for familial hypocalciuric hypercalcemia (FHH1) reveals PTH-dependent and independent CaSR defects. Pflugers Arch 2024; 476:833-845. [PMID: 38386045 PMCID: PMC11033242 DOI: 10.1007/s00424-024-02927-y] [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: 12/19/2023] [Revised: 02/11/2024] [Accepted: 02/12/2024] [Indexed: 02/23/2024]
Abstract
The Calcium-sensing receptor (CaSR) senses extracellular calcium, regulates parathyroid hormone (PTH) secretion, and has additional functions in various organs related to systemic and local calcium and mineral homeostasis. Familial hypocalciuric hypercalcemia type I (FHH1) is caused by heterozygous loss-of-function mutations in the CaSR gene, and is characterized by the combination of hypercalcemia, hypocalciuria, normal to elevated PTH, and facultatively hypermagnesemia and mild bone mineralization defects. To date, only heterozygous Casr null mice have been available as model for FHH1. Here we present a novel mouse FHH1 model identified in a large ENU-screen that carries an c.2579 T > A (p.Ile859Asn) variant in the Casr gene (CasrBCH002 mice). In order to dissect direct effects of the genetic variant from PTH-dependent effects, we crossed CasrBCH002 mice with PTH deficient mice. Heterozygous CasrBCH002 mice were fertile, had normal growth and body weight, were hypercalcemic and hypermagnesemic with inappropriately normal PTH levels and urinary calcium excretion replicating some features of FHH1. Hypercalcemia and hypermagnesemia were independent from PTH and correlated with higher expression of claudin 16 and 19 in kidneys. Likewise, reduced expression of the renal TRPM6 channel in CasrBCH002 mice was not dependent on PTH. In bone, mutations in Casr rescued the bone phenotype observed in Pth null mice by increasing osteoclast numbers and improving the columnar pattern of chondrocytes in the growth zone. In summary, CasrBCH002 mice represent a new model to study FHH1 and our results indicate that only a part of the phenotype is driven by PTH.
Collapse
Affiliation(s)
- Catharina J Küng
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Rocio Fuente
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
- Department of Morphology and Cellular Biology, University of Oviedo, Oviedo, Spain
| | - Betül Haykir
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Martin Hrabĕ de Angelis
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Lehrstuhl Für Experimentelle Genetik, Technische Universität München, Freising-Weihenstephan, Germany
- Member of German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Nati Hernando
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
| |
Collapse
|
3
|
Roskosch J, Huynh-Do U, Rudloff S. Lectin-mediated, time-efficient, and high-yield sorting of different morphologically intact nephron segments. Pflugers Arch 2024; 476:379-393. [PMID: 38091061 PMCID: PMC10847228 DOI: 10.1007/s00424-023-02894-w] [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: 02/28/2023] [Revised: 11/20/2023] [Accepted: 11/24/2023] [Indexed: 02/08/2024]
Abstract
The kidney is a highly complex organ equipped with a multitude of miniscule filter-tubule units called nephrons. Each nephron can be subdivided into multiple segments, each with its own morphology and physiological function. To date, conventional manual approaches to isolate specific nephron segments are very laborious, time-consuming, often limited to only a specific segment, and typically have low yield. Here, we describe a novel, unconventional method that is superior in many aspects to previous protocols by combining low-cost fluorophore-conjugated lectins or agglutinins (Flaggs) with flow sorting. This allows the simultaneous separation of different nephron segments with preserved 3D morphology from mouse or human samples in under 3 h. Using a 200-µm nozzle and 5 psi, glomeruli, proximal, or distal convoluted tubules are sorted with Cy3-labeled Sambucus Nigra agglutinin (SNA-Cy3), Fluorescein-labeled Lotus Tetragonolobus lectin (LTL-FITC), or Pacific Blue-labeled soybean agglutinin (SBA-PB), respectively. Connecting tubules and collecting ducts are sorted by double-positive SBA-PB and SNA-Cy3 signals, while thick ascending limb segments are characterized by the absence of any Flaggs labeling. From two mouse kidneys, this yields 37-521 ng protein/s or 0.71-16.71 ng RNA/s, depending on the specific nephron segment. The purity of sorted segments, as assessed by mRNA expression level profiling of 15 genes, is very high with a 96.1-fold median enrichment across all genes and sorted segments. In summary, our method represents a simple, straightforward, cost-effective, and widely applicable tool yielding high amounts of pure and morphologically largely intact renal tubule materials with the potential to propel nephron segment-specific research.
Collapse
Affiliation(s)
- Jessica Roskosch
- Division of Nephrology and Hypertension, University of Bern and University Hospital Bern, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Uyen Huynh-Do
- Division of Nephrology and Hypertension, University of Bern and University Hospital Bern, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Stefan Rudloff
- Division of Nephrology and Hypertension, University of Bern and University Hospital Bern, Freiburgstrasse 15, CH-3010, Bern, Switzerland.
| |
Collapse
|
4
|
Mpabanzi L, Wainwright J, Boonen B, van Eijk H, Dhar D, Karssemeijer E, Dejong CHC, Jalan R, Schwartz JM, Olde Damink SWM, Soons Z. Fluxomics reveals cellular and molecular basis of increased renal ammoniagenesis. NPJ Syst Biol Appl 2022; 8:49. [PMID: 36539425 PMCID: PMC9768161 DOI: 10.1038/s41540-022-00257-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 11/07/2022] [Indexed: 12/24/2022] Open
Abstract
The kidney plays a critical role in excreting ammonia during metabolic acidosis and liver failure. The mechanisms behind this process have been poorly explored. The present study combines results of in vivo experiments of increased total ammoniagenesis with systems biology modeling, in which eight rats were fed an amino acid-rich diet (HD group) and eight a normal chow diet (AL group). We developed a method based on elementary mode analysis to study changes in amino acid flux occurring across the kidney in increased ammoniagenesis. Elementary modes represent minimal feasible metabolic paths in steady state. The model was used to predict amino acid fluxes in healthy and pre-hyperammonemic conditions, which were compared to experimental fluxes in rats. First, we found that total renal ammoniagenesis increased from 264 ± 68 to 612 ± 87 nmol (100 g body weight)-1 min-1 in the HD group (P = 0.021) and a concomitated upregulation of NKCC2 ammonia and other transporters in the kidney. In the kidney metabolic model, the best predictions were obtained with ammonia transport as an objective. Other objectives resulting in a fair correlation with the measured fluxes (correlation coefficient >0.5) were growth, protein uptake, urea excretion, and lysine and phenylalanine transport. These predictions were improved when specific gene expression data were considered in HD conditions, suggesting a role for the mitochondrial glycine pathway. Further studies are needed to determine if regulation through the mitochondrial glycine pathway and ammonia transporters can be modulated and how to use the kidney as a therapeutic target in hyperammonemia.
Collapse
Affiliation(s)
- Liliane Mpabanzi
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.83440.3b0000000121901201Hepato-Pancreato-Biliary and Liver Transplant Surgery, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK ,grid.83440.3b0000000121901201Liver Failure Group, UCL Hepatology, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK
| | - Jessica Wainwright
- grid.5379.80000000121662407School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT UK
| | - Bas Boonen
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Hans van Eijk
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Dipok Dhar
- grid.83440.3b0000000121901201Hepato-Pancreato-Biliary and Liver Transplant Surgery, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK
| | - Esther Karssemeijer
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Cees H. C. Dejong
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.412301.50000 0000 8653 1507Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Rajiv Jalan
- grid.83440.3b0000000121901201Liver Failure Group, UCL Hepatology, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK
| | - Jean-Marc Schwartz
- grid.5379.80000000121662407School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT UK
| | - Steven W. M. Olde Damink
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.83440.3b0000000121901201Hepato-Pancreato-Biliary and Liver Transplant Surgery, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK ,grid.412301.50000 0000 8653 1507Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Zita Soons
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.412301.50000 0000 8653 1507Research Center for Computational Biomedicine, University Hospital RWTH Aachen, Aachen, Germany
| |
Collapse
|
5
|
Veiras LC, Bernstein EA, Cao D, Okwan-Duodu D, Khan Z, Gibb DR, Roach A, Skelton R, Williams RM, Bernstein KE, Giani JF. Tubular IL-1β Induces Salt Sensitivity in Diabetes by Activating Renal Macrophages. Circ Res 2022; 131:59-73. [PMID: 35574842 PMCID: PMC9233055 DOI: 10.1161/circresaha.121.320239] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronic renal inflammation has been widely recognized as a major promoter of several forms of high blood pressure including salt-sensitive hypertension. In diabetes, IL (interleukin)-6 induces salt sensitivity through a dysregulation of the epithelial sodium channel. However, the origin of this inflammatory process and the molecular events that culminates with an abnormal regulation of epithelial sodium channel and salt sensitivity in diabetes are largely unknown. METHODS Both in vitro and in vivo approaches were used to investigate the molecular and cellular contributors to the renal inflammation associated with diabetic kidney disease and how these inflammatory components interact to develop salt sensitivity in db/db mice. RESULTS Thirty-four-week-old db/db mice display significantly higher levels of IL-1β in renal tubules compared with nondiabetic db/+ mice. Specific suppression of IL-1β in renal tubules prevented salt sensitivity in db/db mice. A primary culture of renal tubular epithelial cells from wild-type mice releases significant levels of IL-1β when exposed to a high glucose environment. Coculture of tubular epithelial cells and bone marrow-derived macrophages revealed that tubular epithelial cell-derived IL-1β promotes the polarization of macrophages towards a proinflammatory phenotype resulting in IL-6 secretion. To evaluate whether macrophages are the cellular target of IL-1β in vivo, diabetic db/db mice were transplanted with the bone marrow of IL-1R1 (IL-1 receptor type 1) knockout mice. db/db mice harboring an IL-1 receptor type 1 knockout bone marrow remained salt resistant, display lower renal inflammation and lower expression and activity of epithelial sodium channel compared with db/db transplanted with a wild-type bone marrow. CONCLUSIONS Renal tubular epithelial cell-derived IL-1β polarizes renal macrophages towards a proinflammatory phenotype that promotes salt sensitivity through the accumulation of renal IL-6. When tubular IL-1β synthesis is suppressed or in db/db mice in which immune cells lack the IL-1R1, macrophage polarization is blunted resulting in no salt-sensitive hypertension.
Collapse
Affiliation(s)
- Luciana C Veiras
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Ellen A Bernstein
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - DuoYao Cao
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | | | - Zakir Khan
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - David R Gibb
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Arantxa Roach
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Rachel Skelton
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Ryan M Williams
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Kenneth E Bernstein
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Jorge F Giani
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| |
Collapse
|
6
|
Dizin E, Olivier V, Roth I, Sassi A, Arnoux G, Ramakrishnan S, Morel S, Kwak BR, Loffing J, Hummler E, Wenger RH, Frew IJ, Feraille E. Activation of the Hypoxia-Inducible Factor Pathway Inhibits Epithelial Sodium Channel-Mediated Sodium Transport in Collecting Duct Principal Cells. J Am Soc Nephrol 2021; 32:3130-3145. [PMID: 34615708 PMCID: PMC8638392 DOI: 10.1681/asn.2021010046] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 08/18/2021] [Accepted: 09/05/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Active sodium reabsorption is the major factor influencing renal oxygen consumption and production of reactive oxygen species (ROS). Increased sodium reabsorption uses more oxygen, which may worsen medullary hypoxia and produce more ROS via enhanced mitochondrial ATP synthesis. Both mechanisms may activate the hypoxia-inducible factor (HIF) pathway. Because the collecting duct is exposed to low oxygen pressure and variations of active sodium transport, we assessed whether the HIF pathway controls epithelial sodium channel (ENaC)-dependent sodium transport. METHODS We investigated HIF's effect on ENaC expression in mpkCCD cl4 cells (a model of collecting duct principal cells) using real-time PCR and western blot and ENaC activity by measuring amiloride-sensitive current. We also assessed the effect of hypoxia and sodium intake on abundance of kidney sodium transporters in wild-type and inducible kidney tubule-specific Hif1α knockout mice. RESULTS In cultured cells, activation of the HIF pathway by dimethyloxalylglycine or hypoxia inhibited sodium transport and decreased expression of β ENaC and γ ENaC, as well as of Na,K-ATPase. HIF1 α silencing increased β ENaC and γ ENaC expression and stimulated sodium transport. A constitutively active mutant of HIF1 α produced the opposite effect. Aldosterone and inhibition of the mitochondrial respiratory chain slowly activated the HIF pathway, suggesting that ROS may also activate HIF. Decreased γ ENaC abundance induced by hypoxia in normal mice was abolished in Hif1α knockout mice. Similarly, Hif1α knockout led to increased γ ENaC abundance under high sodium intake. CONCLUSIONS This study reveals that γ ENaC expression and activity are physiologically controlled by the HIF pathway, which may represent a negative feedback mechanism to preserve oxygenation and/or prevent excessive ROS generation under increased sodium transport.
Collapse
Affiliation(s)
- Eva Dizin
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland,National Centre of Competence in Research “Kidney.CH”, Switzerland
| | - Valérie Olivier
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland,National Centre of Competence in Research “Kidney.CH”, Switzerland
| | - Isabelle Roth
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland,National Centre of Competence in Research “Kidney.CH”, Switzerland
| | - Ali Sassi
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland,National Centre of Competence in Research “Kidney.CH”, Switzerland
| | - Grégoire Arnoux
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland,National Centre of Competence in Research “Kidney.CH”, Switzerland
| | - Suresh Ramakrishnan
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland,National Centre of Competence in Research “Kidney.CH”, Switzerland
| | - Sandrine Morel
- Department of Pathology and Immunology, University of Geneva, CMU, Geneva, Switzerland
| | - Brenda R. Kwak
- Department of Pathology and Immunology, University of Geneva, CMU, Geneva, Switzerland
| | - Johannes Loffing
- National Centre of Competence in Research “Kidney.CH”, Switzerland,Institute of Anatomy, University of Zürich, Zürich, Switzerland
| | - Edith Hummler
- National Centre of Competence in Research “Kidney.CH”, Switzerland,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Roland H. Wenger
- National Centre of Competence in Research “Kidney.CH”, Switzerland,Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Ian J. Frew
- Department of Internal Medicine I, Hematology, Oncology and Stem Cell Transplantation, Faculty of Medicine, Medical Centre - University of Freiburg, Freiburg, Germany
| | - Eric Feraille
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland,National Centre of Competence in Research “Kidney.CH”, Switzerland
| |
Collapse
|
7
|
Torres-Pinzon DL, Ralph DL, Veiras LC, McDonough AA. Sex-specific adaptations to high-salt diet preserve electrolyte homeostasis with distinct sodium transporter profiles. Am J Physiol Cell Physiol 2021; 321:C897-C909. [PMID: 34613843 PMCID: PMC8616593 DOI: 10.1152/ajpcell.00282.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/04/2021] [Accepted: 10/04/2021] [Indexed: 02/04/2023]
Abstract
Kidneys continuously filter an enormous amount of sodium and adapt kidney Na+ reabsorption to match Na+ intake to maintain circulatory volume and electrolyte homeostasis. Males (M) respond to high-salt (HS) diet by translocating proximal tubule Na+/H+ exchanger isoform 3 (NHE3) to the base of the microvilli, reducing activated forms of the distal NaCl cotransporter (NCC) and epithelial Na+ channel (ENaC). Males (M) and females (F) on normal-salt (NS) diet present sex-specific profiles of "transporters" (cotransporters, channels, pumps, and claudins) along the nephron, e.g., F exhibit 40% lower NHE3 and 200% higher NCC abundance than M. We tested the hypothesis that adaptations to HS diet along the nephron will, likewise, exhibit sexual dimorphisms. C57BL/6J mice were fed for 15 days with 4% NaCl diet (HS) versus 0.26% NaCl diet (NS). On HS, M and F exhibited normal plasma [Na+] and [K+], similar urine volume, Na+, K+, and osmolal excretion rates normalized to body weight. In F, like M, HS lowered abundance of distal NCC, phosphorylated NCC, and cleaved (activated) forms of ENaC. The adaptations associated with achieving electrolyte homeostasis exhibit sex-dependent and independent mechanisms. Sex differences in baseline "transporters" abundance persist during HS diet, yet the fold changes during HS diet (normalized to NS) are similar along the distal nephron and collecting duct. Sex-dependent differences observed along the proximal tubule during HS show that female kidneys adapt differently from patterns reported in males, yet achieve and maintain fluid and electrolyte homeostasis.
Collapse
Affiliation(s)
- Diana L Torres-Pinzon
- Department of Physiology and Neuroscience, Keck School of Medicine of University of Southern California, Los Angeles, California
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine of University of Southern California, Los Angeles, California
| | - Luciana C Veiras
- Department of Physiology and Neuroscience, Keck School of Medicine of University of Southern California, Los Angeles, California
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of University of Southern California, Los Angeles, California
| |
Collapse
|
8
|
Moser S, Sugano Y, Wengi A, Fisi V, Lindtoft Rosenbaek L, Mariniello M, Loffing‐Cueni D, McCormick JA, Fenton RA, Loffing J. A five amino acids deletion in NKCC2 of C57BL/6 mice affects analysis of NKCC2 phosphorylation but does not impact kidney function. Acta Physiol (Oxf) 2021; 233:e13705. [PMID: 34114742 PMCID: PMC8384713 DOI: 10.1111/apha.13705] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 05/04/2021] [Accepted: 06/07/2021] [Indexed: 12/24/2022]
Abstract
Aim The phosphorylation level of the furosemide‐sensitive Na+‐K+‐2Cl− cotransporter (NKCC2) in the thick ascending limb (TAL) is used as a surrogate marker for NKCC2 activation and TAL function. However, in mice, analyses of NKCC2 phosphorylation with antibodies against phosphorylated threonines 96 and 101 (anti‐pT96/pT101) give inconsistent results. We aimed (a) to elucidate these inconsistencies and (b) to develop a phosphoform‐specific antibody that ensures reliable detection of NKCC2 phosphorylation in mice. Methods Genetic information, molecular biology, biochemical techniques and mouse phenotyping was used to study NKCC2 and kidney function in two commonly used mouse strains (ie 129Sv and in C57BL/6 mice). Moreover, a new phosphoform‐specific mouse NKCC2 antibody was developed and characterized. Results Amino acids sequence alignment revealed that C57BL/6 mice have a strain‐specific five amino acids deletion (ΔF97‐T101) in NKCC2 that diminishes the detection of NKCC2 phosphorylation with previously developed pT96/pT101 NKCC2 antibodies. Instead, the antibodies cross‐react with the phosphorylated thiazide‐sensitive NaCl cotransporter (NCC), which can obscure interpretation of results. Interestingly, the deletion in NKCC2 does not impact on kidney function and/or expression of renal ion transport proteins as indicated by the analysis of the F2 generation of crossbred 129Sv and C57BL/6 mice. A newly developed pT96 NKCC2 antibody detects pNKCC2 in both mouse strains and shows no cross‐reactivity with phosphorylated NCC. Conclusion Our work reveals a hitherto unappreciated, but essential, strain difference in the amino acids sequence of mouse NKCC2 that needs to be considered when analysing NKCC2 phosphorylation in mice. The new pNKCC2 antibody circumvents this technical caveat.
Collapse
Affiliation(s)
- Sandra Moser
- Institute of Anatomy University of Zurich Zurich Switzerland
| | - Yuya Sugano
- Institute of Anatomy University of Zurich Zurich Switzerland
| | - Agnieszka Wengi
- Institute of Anatomy University of Zurich Zurich Switzerland
| | - Viktoria Fisi
- Institute of Anatomy University of Zurich Zurich Switzerland
| | | | | | | | - James A. McCormick
- Division of Nephrology and Hypertension Oregon Health & Science University Portland OR USA
| | | | - Johannes Loffing
- Institute of Anatomy University of Zurich Zurich Switzerland
- Swiss National Centre for Competence in Research “Kidney control of homeostasis” Zurich Switzerland
| |
Collapse
|
9
|
Prot-Bertoye C, Griveau C, Skjødt K, Cheval L, Brideau G, Lievre L, Ferriere E, Arbaretaz F, Garbin K, Zamani R, Marcussen N, Figueres L, Breiderhoff T, Muller D, Bruneval P, Houillier P, Dimke H. Differential localization patterns of claudin 10, 16, and 19 in human, mouse, and rat renal tubular epithelia. Am J Physiol Renal Physiol 2021; 321:F207-F224. [PMID: 34151590 DOI: 10.1152/ajprenal.00579.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Functional properties of the paracellular pathway depend critically on the set of claudins (CLDN) expressed at the tight junction. Two syndromes are causally linked to loss-of-function mutations of claudins: hypohidrosis, electrolyte imbalance, lacrimal gland dysfunction, ichthyosis, and xerostomia (HELIX) syndrome caused by genetic variations in the CLDN10 gene and familial hypomagnesemia with hypercalciuria and nephrocalcinosis caused by genetic variations in the CLDN16 or CLDN19 genes. All three genes are expressed in the kidney, particularly in the thick ascending limb (TAL). However, localization of these claudins in humans and rodents remains to be delineated in detail. We studied the segmental and subcellular expression of CLDN10, CLDN16, and CLDN19 in both paraffin-embedded and frozen kidney sections from the adult human, mouse, and rat using immunohistochemistry and immunofluorescence, respectively. Here, CLDN10 was present in a subset of medullary and cortical TAL cells, localizing to basolateral domains and tight junctions in human and rodent kidneys. Weak expression was detected at the tight junction of proximal tubular cells. CLDN16 was primarily expressed in a subset of TAL cells in the cortex and outer stripe of outer medulla, restricted to basolateral domains and tight junctional structures in both human and rodent kidneys. CLDN19 predominantly colocalized with CLDN16 in tight junctions and basolateral domains of the TAL but was also found in basolateral and junctional domains in more distal sites. CLDN10 expression at tight junctions almost never overlapped with that of CLND16 and CLDN19, consistent with distinct junctional pathways with different permeation profiles in both human and rodent kidneys.NEW & NOTEWORTHY This study used immunohistochemistry and immunofluorescence to investigate the distribution of claudin 10, 16, and 19 in the human, mouse, and rat kidney. The findings showed distinct junctional pathways in both human and rodent kidneys, supporting the existence of different permeation profiles in all species investigated.
Collapse
Affiliation(s)
- Caroline Prot-Bertoye
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie, Paris, France.,Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Paris, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphate, Paris, France
| | - Camille Griveau
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Karsten Skjødt
- Department of Cancer and Inflammation, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Lydie Cheval
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Gaëlle Brideau
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Loïc Lievre
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Elsa Ferriere
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Floriane Arbaretaz
- Centre d'Histologie, d'Imagerie et de Cytométrie, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France
| | - Kevin Garbin
- Centre d'Histologie, d'Imagerie et de Cytométrie, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France
| | - Reza Zamani
- Department of Urology, Odense University Hospital, Odense, Denmark
| | - Niels Marcussen
- Department of Clinical Pathology, Odense University Hospital, Odense, Denmark
| | - Lucile Figueres
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Tilman Breiderhoff
- Division of Gastroenterology, Nephrology and Metabolic Diseases, Department of Pediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Dominik Muller
- Division of Gastroenterology, Nephrology and Metabolic Diseases, Department of Pediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Patrick Bruneval
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Anatomopathologie, Paris, France
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228-Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie, Paris, France.,Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Paris, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphate, Paris, France
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
McDonough AA, Veiras LC, McFarlin BE, Ralph DL. Impact of casein- versus grain-based diets on rat renal sodium transporters' abundance and regulation. KIDNEY360 2021; 2:519-523. [PMID: 34095853 PMCID: PMC8174819 DOI: 10.34067/kid.0006702020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
12
|
Ayasse N, Berg P, Leipziger J, Sørensen MV. ENaC expression correlates with the acute furosemide-induced K + excretion. Physiol Rep 2021; 9:e14668. [PMID: 33410279 PMCID: PMC7788322 DOI: 10.14814/phy2.14668] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND In the aldosterone-sensitive distal nephron (ASDN), epithelial sodium channel (ENaC)-mediated Na+ absorption drives K+ excretion. K+ excretion depends on the delivery of Na+ to the ASDN and molecularly activated ENaC. Furosemide is known as a K+ wasting diuretic as it greatly enhances Na+ delivery to the ASDN. Here, we studied the magnitude of acute furosemide-induced kaliuresis under various states of basal molecular ENaC activity. METHODS C57/Bl6J mice were subjected to different dietary regimens that regulate molecular ENaC expression and activity levels. The animals were anesthetized and bladder-catheterized. Diuresis was continuously measured before and after administration of furosemide (2 µg/g BW) or benzamil (0.2 µg/g BW). Flame photometry was used to measure urinary [Na+ ] and [K+ ]. The kidneys were harvested and, subsequently, ENaC expression and cleavage activation were determined by semiquantitative western blotting. RESULTS A low K+ and a high Na+ diet markedly suppressed ENaC protein expression, cleavage activation, and furosemide-induced kaliuresis. In contrast, furosemide-induced kaliuresis was greatly enhanced in animals fed a high K+ or low Na+ diet, conditions with increased ENaC expression. The furosemide-induced diuresis was similar in all dietary groups. CONCLUSION Acute furosemide-induced kaliuresis differs greatly and depends on the a priori molecular expression level of ENaC. Remarkably, it can be even absent in animals fed a high Na+ diet, despite a marked increase of tubular flow and urinary Na+ excretion. This study provides auxiliary evidence that acute ENaC-dependent K+ excretion requires both Na+ as substrate and molecular activation of ENaC.
Collapse
Affiliation(s)
- Niklas Ayasse
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - Peder Berg
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - Jens Leipziger
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
- Aarhus Institute of Advanced StudiesAarhus UniversityAarhus CDenmark
| | | |
Collapse
|
13
|
McFarlin BE, Chen Y, Priver TS, Ralph DL, Mercado A, Gamba G, Madhur MS, McDonough AA. Coordinate adaptations of skeletal muscle and kidney to maintain extracellular [K +] during K +-deficient diet. Am J Physiol Cell Physiol 2020; 319:C757-C770. [PMID: 32845718 PMCID: PMC7654654 DOI: 10.1152/ajpcell.00362.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 12/16/2022]
Abstract
Extracellular fluid (ECF) potassium concentration ([K+]) is maintained by adaptations of kidney and skeletal muscle, responses heretofore studied separately. We aimed to determine how these organ systems work in concert to preserve ECF [K+] in male C57BL/6J mice fed a K+-deficient diet (0K) versus 1% K+ diet (1K) for 10 days (n = 5-6/group). During 0K feeding, plasma [K+] fell from 4.5 to 2 mM; hindlimb muscle (gastrocnemius and soleus) lost 28 mM K+ (from 115 ± 2 to 87 ± 2 mM) and gained 27 mM Na+ (from 27 ± 0.4 to 54 ± 2 mM). Doubling of muscle tissue [Na+] was not associated with inflammation, cytokine production or hypertension as reported by others. Muscle transporter adaptations in 0K- versus 1K-fed mice, assessed by immunoblot, included decreased sodium pump α2-β2 subunits, decreased K+-Cl- cotransporter isoform 3, and increased phosphorylated (p) Na+,K+,2Cl- cotransporter isoform 1 (NKCC1p), Ste20/SPS-1-related proline-alanine rich kinase (SPAKp), and oxidative stress-responsive kinase 1 (OSR1p) consistent with intracellular fluid (ICF) K+ loss and Na+ gain. Renal transporters' adaptations, effecting a 98% reduction in K+ excretion, included two- to threefold increased phosphorylated Na+-Cl- cotransporter (NCCp), SPAKp, and OSR1p abundance, limiting Na+ delivery to epithelial Na+ channels where Na+ reabsorption drives K+ secretion; and renal K sensor Kir 4.1 abundance fell 25%. Mass balance estimations indicate that over 10 days of 0K feeding, mice lose ~48 μmol K+ into the urine and muscle shifts ~47 μmol K+ from ICF to ECF, illustrating the importance of the concerted responses during K+ deficiency.
Collapse
Affiliation(s)
- Brandon E McFarlin
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Yuhan Chen
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Cardiology, Nanjing University Medical School, Nanjing, China
| | - Taylor S Priver
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Adriana Mercado
- Department of Nephrology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Meena S Madhur
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| |
Collapse
|
14
|
Genini A, Mohebbi N, Daryadel A, Bettoni C, Wagner CA. Adaptive response of the murine collecting duct to alkali loading. Pflugers Arch 2020; 472:1079-1092. [DOI: 10.1007/s00424-020-02423-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/31/2020] [Accepted: 06/19/2020] [Indexed: 01/14/2023]
|
15
|
Penton D, Vohra T, Banki E, Wengi A, Weigert M, Forst AL, Bandulik S, Warth R, Loffing J. Collecting system-specific deletion of Kcnj10 predisposes for thiazide- and low-potassium diet-induced hypokalemia. Kidney Int 2020; 97:1208-1218. [PMID: 32299681 DOI: 10.1016/j.kint.2019.12.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 12/17/2022]
Abstract
The basolateral potassium channel KCNJ10 (Kir4.1), is expressed in the renal distal convoluted tubule and controls the activity of the thiazide-sensitive sodium chloride cotransporter. Loss-of-function mutations of KCNJ10 cause EAST/SeSAME syndrome with salt wasting and severe hypokalemia. KCNJ10 is also expressed in the principal cells of the collecting system. However, its pathophysiological role in this segment has not been studied in detail. To address this, we generated the mouse model AQP2cre:Kcnj10flox/flox with a deletion of Kcnj10 specifically in the collecting system (collecting system-Kcnj10-knockout). Collecting system-Kcnj10-knockout mice responded normally to standard and high potassium diet. However, this knockout exhibited a higher kaliuresis and lower plasma potassium than control mice when treated with thiazide diuretics. Likewise, collecting systemKcnj10-knockout displayed an inadequately high kaliuresis and renal sodium retention upon dietary potassium restriction. In this condition, these knockout mice became hypokalemic due to insufficient downregulation of the epithelial sodium channel (ENaC) and the renal outer medullary potassium channel (ROMK) in the collecting system. Consistently, the phenotype of collecting system-Kcnj10-knockout was fully abrogated by ENaC inhibition with amiloride and ameliorated by genetic inactivation of ROMK in the collecting system. Thus, KCNJ10 in the collecting system contributes to the renal control of potassium homeostasis by regulating ENaC and ROMK. Hence, impaired KCNJ10 function in the collecting system predisposes for thiazide and low potassium diet-induced hypokalemia and likely contributes to the pathophysiology of renal potassium loss in EAST/SeSAME syndrome.
Collapse
Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Twinkle Vohra
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Eszter Banki
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Agnieszka Wengi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Maria Weigert
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Anna-Lena Forst
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland.
| |
Collapse
|
16
|
Dizin E, Olivier V, Maire C, Komarynets O, Sassi A, Roth I, Loffing J, de Seigneux S, Maillard M, Rutkowski JM, Edwards A, Feraille E. Time-course of sodium transport along the nephron in nephrotic syndrome: The role of potassium. FASEB J 2019; 34:2408-2424. [PMID: 31908015 DOI: 10.1096/fj.201901345r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 11/21/2019] [Accepted: 11/30/2019] [Indexed: 11/11/2022]
Abstract
The mechanism of sodium retention and its location in kidney tubules may vary with time in nephrotic syndrome (NS). We studied the mechanisms of sodium retention in transgenic POD-ATTAC mice, which display an inducible podocyte-specific apoptosis. At day 2 after the induction of NS, the increased abundance of NHE3 and phosphorylated NCC in nephrotic mice compared with controls suggest that early sodium retention occurs mainly in the proximal and distal tubules. At day 3, the abundance of NHE3 normalized, phosphorylated NCC levels decreased, and cleavage and apical localization of γ-ENaC increased in nephrotic mice. These findings indicate that sodium retention shifted from the proximal and distal tubules to the collecting system. Increased cleavage and apical localization of γ-ENaC persisted at day 5 in nephrotic mice when hypovolemia resolved and steady-state was reached. Sodium retention and γ-ENaC cleavage were independent of the increased plasma levels of aldosterone. Nephrotic mice displayed decreased glomerular filtration rate and urinary potassium excretion associated with hyperkaliemia at day 3. Feeding nephrotic mice with a low potassium diet prevented hyperkaliemia, γ-ENaC cleavage, and led to persistent increased phosphorylation of NCC. These results suggest that potassium homeostasis is a major determinant of the tubular site of sodium retention in nephrotic mice.
Collapse
Affiliation(s)
- Eva Dizin
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zürich, Switzerland
| | - Valérie Olivier
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zürich, Switzerland
| | - Charline Maire
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zürich, Switzerland
| | - Olga Komarynets
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland
| | - Ali Sassi
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland
| | - Isabelle Roth
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zürich, Switzerland
| | - Johannes Loffing
- National Centre of Competence in Research "Kidney.ch", Zürich, Switzerland.,Institute of Anatomy, University of Zürich, Zürich, Switzerland
| | - Sophie de Seigneux
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zürich, Switzerland
| | - Marc Maillard
- Service of Nephrology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Joseph M Rutkowski
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX, USA
| | - Aurélie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Eric Feraille
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, Geneva, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zürich, Switzerland
| |
Collapse
|
17
|
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.
Collapse
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.
| |
Collapse
|
18
|
Ydegaard R, Svenningsen P, Bistrup C, Andersen RF, Stubbe J, Buhl KB, Marcussen N, Hinrichs GR, Iraqi H, Zamani R, Dimke H, Jensen BL. Nephrotic syndrome is associated with increased plasma K + concentration, intestinal K + losses, and attenuated urinary K + excretion: a study in rats and humans. Am J Physiol Renal Physiol 2019; 317:F1549-F1562. [PMID: 31566427 DOI: 10.1152/ajprenal.00179.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The present study tested the hypotheses that nephrotic syndrome (NS) leads to renal K+ loss because of augmented epithelial Na+ channel (ENaC) activity followed by downregulation of renal K+ secretory pathways by suppressed aldosterone. The hypotheses were addressed by determining K+ balance and kidney abundance of K+ and Na+ transporter proteins in puromycin aminonucleoside (PAN)-induced rat nephrosis. The effects of amiloride and angiotensin II type 1 receptor and mineralocorticoid receptor (MR) antagonists were tested. Glucocorticoid-dependent MR activation was tested by suppression of endogenous glucocorticoid with dexamethasone. Urine and plasma samples were obtained from pediatric patients with NS in acute and remission phases. PAN-induced nephrotic rats had ENaC-dependent Na+ retention and displayed lower renal K+ excretion but elevated intestinal K+ secretion that resulted in less cumulated K+ in NS. Aldosterone was suppressed at day 8. The NS-associated changes in intestinal, but not renal, K+ handling responded to suppression of corticosterone, whereas angiotensin II type 1 receptor and MR blockers and amiloride had no effect on urine K+ excretion during NS. In PAN-induced nephrosis, kidney protein abundance of the renal outer medullary K+ channel and γ-ENaC were unchanged, whereas the Na+-Cl- cotransporter was suppressed and Na+-K+-ATPase increased. Pediatric patients with acute NS displayed suppressed urine Na+-to-K+ ratios compared with remission and elevated plasma K+ concentration, whereas fractional K+ excretion did not differ. Acute NS is associated with less cumulated K+ in a rat model, whereas patients with acute NS have elevated plasma K+ and normal renal fractional K+ excretion. In NS rats, K+ balance is not coupled to ENaC activity but results from opposite changes in renal and fecal K+ excretion with a contribution from corticosteroid MR-driven colonic secretion.
Collapse
Affiliation(s)
- Rikke Ydegaard
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Per Svenningsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Claus Bistrup
- Department of Nephrology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | | | - Jane Stubbe
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | | | - Niels Marcussen
- Department of Clinical Pathology, Odense University Hospital, Odense, Denmark
| | - Gitte Rye Hinrichs
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Hiba Iraqi
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Reza Zamani
- Department of Urology, Odense University Hospital, Odense, Denmark
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| |
Collapse
|
19
|
van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
Collapse
Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| |
Collapse
|
20
|
Spirli A, Cheval L, Debonneville A, Penton D, Ronzaud C, Maillard M, Doucet A, Loffing J, Staub O. The serine-threonine kinase PIM3 is an aldosterone-regulated protein in the distal nephron. Physiol Rep 2019; 7:e14177. [PMID: 31397090 PMCID: PMC6687858 DOI: 10.14814/phy2.14177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/20/2019] [Accepted: 06/20/2019] [Indexed: 12/30/2022] Open
Abstract
The mineralocorticoid hormone aldosterone plays a crucial role in the control of Na+ and K+ balance, blood volume, and arterial blood pressure, by acting in the aldosterone-sensitive distal nephron (ASDN) and stimulating a complex transcriptional, translational, and cellular program. Because the complexity of the aldosterone response is still not fully appreciated, we aimed at identifying new elements in this pathway. Here, we demonstrate that the expression of the proto-oncogene PIM3 (Proviral Integration Site of Moloney Murine Leukemia Virus 3), a serine/threonine kinase belonging to the calcium/calmodulin-regulated group of kinases, is stimulated by aldosterone in vitro (mCCDcl1 cells), ex vivo (mouse kidney slices), and in vivo in mice. Characterizing a germline Pim3-/- mouse model, we found that these mice have an upregulated Renin-Angiotensin-Aldosterone System (RAAS), with high circulating aldosterone and plasma renin activity levels on both standard or Na+ -deficient diet. Surprisingly, we did not observe any obvious salt-losing phenotype in Pim3 KO mice as shown by normal blood pressure, plasma and urinary electrolytes, as well as unchanged expression levels of the major Na+ transport proteins. These observations suggest that the potential effects of the loss of the Pim3 gene are physiologically compensated. Indeed, the 2 other family members of the PIM kinase family, PIM1 and PIM2 are upregulated in the kidney of Pim3-/- mice, and may therefore be involved in such compensation. In conclusion, our data demonstrate that the PIM3 kinase is a novel aldosterone-induced protein, but its precise role in aldosterone-dependent renal homeostasis remains to be determined.
Collapse
Affiliation(s)
- Alessia Spirli
- Department of Pharmacology & ToxicologyUniversity of LausanneLausanneSwitzerland
- National Centre of Competence in Research “Kidney.ch”LausanneSwitzerland
| | - Lydie Cheval
- Centre de Recherche des CordeliersINSERM, Sorbonne Universités, USPC, Université Paris Descartes, Université Paris Diderot, Physiologie Rénale et TubulopathiesParisFrance
| | - Anne Debonneville
- Department of Pharmacology & ToxicologyUniversity of LausanneLausanneSwitzerland
- National Centre of Competence in Research “Kidney.ch”LausanneSwitzerland
| | - David Penton
- National Centre of Competence in Research “Kidney.ch”LausanneSwitzerland
- Institute of AnatomyUniversity of ZurichZurichSwitzerland
| | - Caroline Ronzaud
- Department of Pharmacology & ToxicologyUniversity of LausanneLausanneSwitzerland
- National Centre of Competence in Research “Kidney.ch”LausanneSwitzerland
| | - Marc Maillard
- Service of NephrologyLausanne University Hospital (CHUV)LausanneSwitzerland
| | - Alain Doucet
- Centre de Recherche des CordeliersINSERM, Sorbonne Universités, USPC, Université Paris Descartes, Université Paris Diderot, Physiologie Rénale et TubulopathiesParisFrance
| | - Johannes Loffing
- National Centre of Competence in Research “Kidney.ch”LausanneSwitzerland
- Institute of AnatomyUniversity of ZurichZurichSwitzerland
| | - Olivier Staub
- Department of Pharmacology & ToxicologyUniversity of LausanneLausanneSwitzerland
- National Centre of Competence in Research “Kidney.ch”LausanneSwitzerland
| |
Collapse
|
21
|
Koizumi M, Ueda K, Niimura F, Nishiyama A, Yanagita M, Saito A, Pastan I, Fujita T, Fukagawa M, Matsusaka T. Podocyte Injury Augments Intrarenal Angiotensin II Generation and Sodium Retention in a Megalin-Dependent Manner. Hypertension 2019; 74:509-517. [PMID: 31352823 DOI: 10.1161/hypertensionaha.118.12352] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have previously shown that podocyte injury increases the glomerular filtration of liver-derived Agt (angiotensinogen) and the generation of intrarenal Ang II (angiotensin II) and that the filtered Agt is reabsorbed by proximal tubules in a manner dependent on megalin. In the present study, we aimed to study the role of megalin in the generation of renal Ang II and sodium handling during nephrotic syndrome. We generated proximal tubule-specific megalin KO (knockout) mice and crossed these animals with NEP25 mice, in which podocyte-specific injury can be induced by injection of the immunotoxin LMB2. Without podocyte injury, renal Agt staining was markedly diminished and urinary Agt increased in KO mice. However, renal Ang II was similar between KO and control mice on average: 117 (95% CI, 101-134) versus 101 (95% CI, 68-133) fmol/g tissue. We next tested the effect of megalin KO on intrarenal Ang II generation with podocyte injury. Control NEP25 mice showed markedly increased renal Agt staining and renal Ang II levels: 450 (336-565) fmol/g tissue. Megalin KO/NEP25 mice showed markedly diminished Agt reabsorption and attenuated renal Ang II: 199 (156-242) fmol/g tissue (P<0.001). Compared with control NEP25 mice, megalin KO/NEP25 mice excreted 5-fold more sodium in the urine. Western blot analysis showed that megalin KO decreased NHE3 and the cleaved α and γ forms of Epithelial Na Channel. These data indicate that Agt reabsorbed by proximal tubules via megalin in nephrotic syndrome is converted to Ang II, which may contribute to sodium retention and edema formation by activating NHE3 and Epithelial Na Channel.
Collapse
Affiliation(s)
- Masahiro Koizumi
- From the Department of Nephrology, Endocrinology and Metabolism (M.K., M.F.), Tokai University School of Medicine, Isehara, Japan.,Department of Basic Medicine (M.K., T.M.), Tokai University School of Medicine, Isehara, Japan
| | - Kohei Ueda
- Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., T.F.)
| | - Fumio Niimura
- Department of Pediatrics (F.N.), Tokai University School of Medicine, Isehara, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University School of Medicine, Miki-cho, Kita-gun, Japan (A.N.)
| | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Japan (M.Y.)
| | - Akihiko Saito
- Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Japan (A.S.)
| | - Ira Pastan
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institutes, National Institutes of Health, Bethesda, MD (I.P.)
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., T.F.)
| | - Masafumi Fukagawa
- From the Department of Nephrology, Endocrinology and Metabolism (M.K., M.F.), Tokai University School of Medicine, Isehara, Japan
| | - Taiji Matsusaka
- Department of Basic Medicine (M.K., T.M.), Tokai University School of Medicine, Isehara, Japan.,Institute of Medical Sciences, Tokai University, Isehara, Japan (T.M.)
| |
Collapse
|
22
|
Penton D, Moser S, Wengi A, Czogalla J, Rosenbaek LL, Rigendinger F, Faresse N, Martins JR, Fenton RA, Loffing-Cueni D, Loffing J. Protein Phosphatase 1 Inhibitor-1 Mediates the cAMP-Dependent Stimulation of the Renal NaCl Cotransporter. J Am Soc Nephrol 2019; 30:737-750. [PMID: 30902838 DOI: 10.1681/asn.2018050540] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 02/06/2019] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND A number of cAMP-elevating hormones stimulate phosphorylation (and hence activity) of the NaCl cotransporter (NCC) in the distal convoluted tubule (DCT). Evidence suggests that protein phosphatase 1 (PP1) and other protein phosphatases modulate NCC phosphorylation, but little is known about PP1's role and the mechanism regulating its function in the DCT. METHODS We used ex vivo mouse kidney preparations to test whether a DCT-enriched inhibitor of PP1, protein phosphatase 1 inhibitor-1 (I1), mediates cAMP's effects on NCC, and conducted yeast two-hybrid and coimmunoprecipitation experiments in NCC-expressing MDCK cells to explore protein interactions. RESULTS Treating isolated DCTs with forskolin and IBMX increased NCC phosphorylation via a protein kinase A (PKA)-dependent pathway. Ex vivo incubation of mouse kidney slices with isoproterenol, norepinephrine, and parathyroid hormone similarly increased NCC phosphorylation. The cAMP-induced stimulation of NCC phosphorylation strongly correlated with the phosphorylation of I1 at its PKA consensus phosphorylation site (a threonine residue in position 35). We also found an interaction between NCC and the I1-target PP1. Moreover, PP1 dephosphorylated NCC in vitro, and the PP1 inhibitor calyculin A increased NCC phosphorylation. Studies in kidney slices and isolated perfused kidneys of control and I1-KO mice demonstrated that I1 participates in the cAMP-induced stimulation of NCC. CONCLUSIONS Our data suggest a complete signal transduction pathway by which cAMP increases NCC phosphorylation via a PKA-dependent phosphorylation of I1 and subsequent inhibition of PP1. This pathway might be relevant for the physiologic regulation of renal sodium handling by cAMP-elevating hormones, and may contribute to salt-sensitive hypertension in patients with endocrine disorders or sympathetic hyperactivity.
Collapse
Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Sandra Moser
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Agnieszka Wengi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Jan Czogalla
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Lena Lindtoft Rosenbaek
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and.,Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Nourdine Faresse
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Joana R Martins
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and
| | | | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; .,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| |
Collapse
|
23
|
Molecular mechanisms for the regulation of blood pressure by potassium. CURRENT TOPICS IN MEMBRANES 2019; 83:285-313. [PMID: 31196607 DOI: 10.1016/bs.ctm.2019.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has been well documented that the amount of potassium in the diet is associated with blood pressure levels in the population: the higher the potassium consumption, the lower the blood pressure and the cardiovascular mortality. In the last few years certain mechanisms for potassium regulation of salt reabsorption in the kidney have been elucidated at the molecular level. In this work we discuss the evidence demonstrating the relationship between potassium intake and blood pressure levels in human populations and in animal models, as well as the experimental data that reveal the effects of potassium on transepithelial Na+ reabsorption in different nephron segments. We also discuss the physiological relevance of K+-induced natriuresis, and finally, we focus on the molecular mechanisms by which extracellular potassium modulates the activity of the renal NaCl cotransporter, which is the mechanism that has been best dissected so far.
Collapse
|
24
|
Craigie E, Menzies RI, Larsen CK, Jacquillet G, Carrel M, Wildman SS, Loffing J, Leipziger J, Shirley DG, Bailey MA, Unwin RJ. The renal and blood pressure response to low sodium diet in P2X4 receptor knockout mice. Physiol Rep 2018; 6:e13899. [PMID: 30350402 PMCID: PMC6198136 DOI: 10.14814/phy2.13899] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/25/2018] [Accepted: 09/27/2018] [Indexed: 01/02/2023] Open
Abstract
In the kidney, purinergic (P2) receptor-mediated ATP signaling has been shown to be an important local regulator of epithelial sodium transport. Appropriate sodium regulation is crucial for blood pressure (BP) control and disturbances in sodium balance can lead to hypo- or hypertension. Links have already been established between P2 receptor signaling and the development of hypertension, attributed mainly to vascular and/or inflammatory effects. A transgenic mouse model with deletion of the P2X4 receptor (P2X4-/- ) is known to have hypertension, which is thought to reflect endothelial dysfunction and impaired nitric oxide (NO) release. However, renal function in this model has not been characterized; moreover, studies in vitro have shown that the P2X4 receptor can regulate renal epithelial Na+ channel (ENaC) activity. Therefore, in the present study we investigated renal function and sodium handling in P2X4-/- mice, focusing on ENaC-mediated Na+ reabsorption. We confirmed an elevated BP in P2X4-/- mice compared with wild-type mice, but found that ENaC-mediated Na+ reabsorption is no different from wild-type and does not contribute to the raised BP observed in the knockout. However, when P2X4-/- mice were placed on a low sodium diet, BP normalized. Plasma aldosterone concentration tended to increase according to sodium restriction status in both genotypes; in contrast to wild-types, P2X4-/- mice did not show an increase in functional ENaC activity. Thus, although the increased BP in P2X4-/- mice has been attributed to endothelial dysfunction and impaired NO release, there is also a sodium-sensitive component.
Collapse
Affiliation(s)
- Eilidh Craigie
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
- Institue for AnatomyUniversity of ZürichZürichSwitzerland
| | - Robert I. Menzies
- British Heart Foundation Centre for Cardiovascular ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Casper K. Larsen
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - Grégory Jacquillet
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
| | - Monique Carrel
- Institue for AnatomyUniversity of ZürichZürichSwitzerland
| | - Scott S. Wildman
- Urinary System Physiology UnitMedway School of PharmacyUniversity of KentKentUnited Kingdom
| | | | - Jens Leipziger
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - David G. Shirley
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
| | - Matthew A. Bailey
- British Heart Foundation Centre for Cardiovascular ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Robert J. Unwin
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
- CVRM iMEDAstraZeneca GothenburgGothenburgSweden
| |
Collapse
|
25
|
Zachar R, Al-Mashhadi A, Dimke H, Svenningsen P, Jensen BL, Carlström M. Hydronephrosis is associated with elevated plasmin in urine in pediatric patients and rats and changes in NCC and γ-ENaC abundance in rat kidney. Am J Physiol Renal Physiol 2018; 315:F547-F557. [DOI: 10.1152/ajprenal.00635.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Obstruction of urine flow at the level of the pelvo-ureteric junction (UPJO) and subsequent development of hydronephrosis is one of the most common congenital renal malformations. UPJO is associated with development of salt-sensitive hypertension, which is set by the obstructed kidney, and with a stimulated renin-angiotensin-aldosterone system (RAAS) in rodent models. This study aimed at investigating the hypothesis that 1) in pediatric patients with UPJO the RAAS is activated before surgical relief of the obstruction; 2) in rats with UPJO the RAAS activation is reflected by increased abundance of renal aldosterone-stimulated Na transporters; and 3) the injured UPJO kidney allows aberrant filtration of plasminogen, leading to proteolytic activation of the epithelial Na channel γ-subunit (γ-ENaC). Hydronephrosis resulting from UPJO in pediatric patients and rats was associated with increased urinary plasminogen-to-creatinine ratio. In pediatric patients, plasma renin, angiotensin II, urine and plasma aldosterone, and urine soluble prorenin receptor did not differ significantly before or after surgery, or compared with controls. Increased plasmin-to-plasminogen ratio was seen in UPJO rats. Intact γ-ENaC abundance was not changed in UPJO kidney, whereas low-molecular cleavage product abundance increased. The Na-Cl cotransporter displayed significantly lower abundance in the UPJO kidney compared with the nonobstructed contralateral kidney. The Na-K-ATPase α-subunit was unaltered. Treatment with an angiotensin-converting enzyme inhibitor (8 days, captopril) significantly lowered blood pressure in UPJO rats. It is concluded that the RAAS contributes to hypertension following partial obstruction of urine flow at the pelvo-ureteric junction with potential contribution from proteolytic activation of ENaC.
Collapse
Affiliation(s)
- Rikke Zachar
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Ammar Al-Mashhadi
- Pediatric Surgery Section, Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Per Svenningsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Boye L. Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
26
|
Huang J, Montani JP, Verrey F, Feraille E, Ming XF, Yang Z. Arginase-II negatively regulates renal aquaporin-2 and water reabsorption. FASEB J 2018; 32:5520-5531. [PMID: 29718707 PMCID: PMC6405175 DOI: 10.1096/fj.201701209r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Type-II l-arginine:ureahydrolase, arginase-II (Arg-II), is abundantly
expressed in the kidney. The physiologic role played by Arg-II in the kidney remains
unknown. Herein, we report that in mice that are deficient in Arg-II
(Arg-II−/−), total and membrane-associated aquaporin-2
(AQP2) protein levels were significantly higher compared with wild-type (WT)
controls. Water deprivation enhanced Arg-II expression, AQP2 levels, and membrane
association in collecting ducts. Effects of water deprivation on AQP2 were stronger
in Arg-II−/− mice than in WT mice. Accordingly, a decrease
in urine volume and an increase in urine osmolality under water deprivation were more
pronounced in Arg-II−/− mice than in WT mice, which
correlated with a weaker increase in plasma osmolality in
Arg-II−/− mice. There was no difference in vasopressin
release under water deprivation conditions between either genotype of mice. Although
total AQP2 and phosphorylated AQP2-S256 levels (mediated by PKA) in kidneys under
water deprivation conditions were significantly higher in
Arg-II−/− mice compared with WT animals, there is no
difference in the ratio of AQP2-S256:AQP2. In cultured mouse collecting duct
principal mCCDcl1 cells, expression of both Arg-II and AQP2 were enhanced
by the vasopressin type 2 receptor agonist, desamino-d-arginine
vasopressin (dDAVP). Silencing Arg-II enhanced the expression and membrane
association of AQP2 by dDAVP without influencing cAMP levels. In conclusion,
in vivo and in vitro experiments demonstrate
that Arg-II negatively regulates AQP2 and the urine-concentrating capability in
kidneys via a mechanism that is not associated with the modulation
of the cAMP pathway.—Huang, J., Montani, J.-P., Verrey, F., Feraille, E.,
Ming, X.-F., Yang, Z. Arginase-II negatively regulates renal aquaporin-2 and water
reabsorption.
Collapse
Affiliation(s)
- Ji Huang
- Division of Physiology, Department of Medicine, Cardiovascular and Aging Research, University of Fribourg, Fribourg, Switzerland.,Kidney Control of Homeostasis, National Center of Competence in Research, Zurich, Switzerland
| | - Jean-Pierre Montani
- Division of Physiology, Department of Medicine, Cardiovascular and Aging Research, University of Fribourg, Fribourg, Switzerland.,Kidney Control of Homeostasis, National Center of Competence in Research, Zurich, Switzerland
| | - François Verrey
- Kidney Control of Homeostasis, National Center of Competence in Research, Zurich, Switzerland.,Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Eric Feraille
- Kidney Control of Homeostasis, National Center of Competence in Research, Zurich, Switzerland.,Department of Cell Biology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Xiu-Fen Ming
- Division of Physiology, Department of Medicine, Cardiovascular and Aging Research, University of Fribourg, Fribourg, Switzerland.,Kidney Control of Homeostasis, National Center of Competence in Research, Zurich, Switzerland
| | - Zhihong Yang
- Division of Physiology, Department of Medicine, Cardiovascular and Aging Research, University of Fribourg, Fribourg, Switzerland.,Kidney Control of Homeostasis, National Center of Competence in Research, Zurich, Switzerland
| |
Collapse
|
27
|
Trepiccione F, Soukaseum C, Baudrie V, Kumai Y, Teulon J, Villoutreix B, Cornière N, Wangemann P, Griffith AJ, Byung Choi Y, Hadchouel J, Chambrey R, Eladari D. Acute genetic ablation of pendrin lowers blood pressure in mice. Nephrol Dial Transplant 2018; 32:1137-1145. [PMID: 28064162 DOI: 10.1093/ndt/gfw393] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 10/02/2016] [Indexed: 11/14/2022] Open
Abstract
Background Pendrin, the chloride/bicarbonate exchanger of β-intercalated cells of the renal connecting tubule and the collecting duct, plays a key role in NaCl reabsorption by the distal nephron. Therefore, pendrin may be important for the control of extracellular fluid volume and blood pressure. Methods Here, we have used a genetic mouse model in which the expression of pendrin can be switched-on in vivo by the administration of doxycycline. Pendrin can also be rapidly removed when doxycycline administration is discontinued. Therefore, our genetic strategy allows us to test selectively the acute effects of loss of pendrin function. Results We show that acute loss of pendrin leads to a significant decrease of blood pressure. In addition, acute ablation of pendrin did not alter significantly the acid-base status or blood K + concentration. Conclusion By using a transgenic mouse model, avoiding off-target effects related to pharmacological compounds, this study suggests that pendrin could be a novel target to treat hypertension.
Collapse
Affiliation(s)
- Francesco Trepiccione
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Christelle Soukaseum
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Veronique Baudrie
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France.,Hôpital Européen Georges Pompidou, Département de Physiologie, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Yusuke Kumai
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Jacques Teulon
- CNRS ERL 8228, INSERM UMRS 1138, Université Pierre et Marie Curie, Centre de Recherche des Cordeliers, Paris, France
| | - Bruno Villoutreix
- INSERM U973, MTi-Bioinformatics; University Paris Diderot, Paris, France
| | - Nicolas Cornière
- Service d'Explorations Fonctionnelles Rénales, Hôpital Felix Guyon, CHU de la Réunion, St Denis, Ile de la Réunion, France
| | - Philine Wangemann
- Anatomy and Physiology Department, Kansas State University, Manhattan, KS, USA
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Yoon Byung Choi
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Juliette Hadchouel
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Regine Chambrey
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France.,Centre National de la Recherche Scientifique, Paris, France
| | - Dominique Eladari
- Service d'Explorations Fonctionnelles Rénales, Hôpital Felix Guyon, CHU de la Réunion, St Denis, Ile de la Réunion, France
| |
Collapse
|
28
|
Boscardin E, Perrier R, Sergi C, Maillard MP, Loffing J, Loffing-Cueni D, Koesters R, Rossier BC, Hummler E. Plasma Potassium Determines NCC Abundance in Adult Kidney-Specific γENaC Knockout. J Am Soc Nephrol 2018; 29:977-990. [PMID: 29371419 DOI: 10.1681/asn.2017030345] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 11/30/2017] [Indexed: 12/18/2022] Open
Abstract
The amiloride-sensitive epithelial sodium channel (ENaC) and the thiazide-sensitive sodium chloride cotransporter (NCC) are key regulators of sodium and potassium and colocalize in the late distal convoluted tubule of the kidney. Loss of the αENaC subunit leads to a perinatal lethal phenotype characterized by sodium loss and hyperkalemia resembling the human syndrome pseudohypoaldosteronism type 1 (PHA-I). In adulthood, inducible nephron-specific deletion of αENaC in mice mimics the lethal phenotype observed in neonates, and as in humans, this phenotype is prevented by a high sodium (HNa+)/low potassium (LK+) rescue diet. Rescue reflects activation of NCC, which is suppressed at baseline by elevated plasma potassium concentration. In this study, we investigated the role of the γENaC subunit in the PHA-I phenotype. Nephron-specific γENaC knockout mice also presented with salt-wasting syndrome and severe hyperkalemia. Unlike mice lacking αENaC or βΕΝaC, an HNa+/LK+ diet did not normalize plasma potassium (K+) concentration or increase NCC activation. However, when K+ was eliminated from the diet at the time that γENaC was deleted, plasma K+ concentration and NCC activity remained normal, and progressive weight loss was prevented. Loss of the late distal convoluted tubule, as well as overall reduced βENaC subunit expression, may be responsible for the more severe hyperkalemia. We conclude that plasma K+ concentration becomes the determining and limiting factor in regulating NCC activity, regardless of Na+ balance in γENaC-deficient mice.
Collapse
Affiliation(s)
- Emilie Boscardin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Center of Competence in Research "Kidney.Control of Homeostasis," Lausanne and Zurich, Switzerland
| | - Romain Perrier
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Chloé Sergi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Marc P Maillard
- Service of Nephrology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Johannes Loffing
- National Center of Competence in Research "Kidney.Control of Homeostasis," Lausanne and Zurich, Switzerland.,Institute of Anatomy, University of Zurich, Zurich, Switzerland; and
| | | | - Robert Koesters
- Department of Nephrology, Hôpital Tenon, Université Pierre et Marie Curie, Paris, France
| | - Bernard C Rossier
- Department of Pharmacology and Toxicology, 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," Lausanne and Zurich, Switzerland
| |
Collapse
|
29
|
Bohnert BN, Menacher M, Janessa A, Wörn M, Schork A, Daiminger S, Kalbacher H, Häring HU, Daniel C, Amann K, Sure F, Bertog M, Haerteis S, Korbmacher C, Artunc F. Aprotinin prevents proteolytic epithelial sodium channel (ENaC) activation and volume retention in nephrotic syndrome. Kidney Int 2018; 93:159-172. [DOI: 10.1016/j.kint.2017.07.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 10/18/2022]
|
30
|
Udwan K, Abed A, Roth I, Dizin E, Maillard M, Bettoni C, Loffing J, Wagner CA, Edwards A, Feraille E. Dietary sodium induces a redistribution of the tubular metabolic workload. J Physiol 2017; 595:6905-6922. [PMID: 28940314 PMCID: PMC5685825 DOI: 10.1113/jp274927] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/11/2017] [Indexed: 01/11/2023] Open
Abstract
Key points Body Na+ content is tightly controlled by regulated urinary Na+ excretion. The intrarenal mechanisms mediating adaptation to variations in dietary Na+ intake are incompletely characterized. We confirmed and expanded observations in mice that variations in dietary Na+ intake do not alter the glomerular filtration rate but alter the total and cell‐surface expression of major Na+ transporters all along the kidney tubule. Low dietary Na+ intake increased Na+ reabsorption in the proximal tubule and decreased it in more distal kidney tubule segments. High dietary Na+ intake decreased Na+ reabsorption in the proximal tubule and increased it in distal segments with lower energetic efficiency. The abundance of apical transporters and Na+ delivery are the main determinants of Na+ reabsorption along the kidney tubule. Tubular O2 consumption and the efficiency of sodium reabsorption are dependent on sodium diet.
Abstract Na+ excretion by the kidney varies according to dietary Na+ intake. We undertook a systematic study of the effects of dietary salt intake on glomerular filtration rate (GFR) and tubular Na+ reabsorption. We examined the renal adaptive response in mice subjected to 7 days of a low sodium diet (LSD) containing 0.01% Na+, a normal sodium diet (NSD) containing 0.18% Na+ and a moderately high sodium diet (HSD) containing 1.25% Na+. As expected, LSD did not alter measured GFR and increased the abundance of total and cell‐surface NHE3, NKCC2, NCC, α‐ENaC and cleaved γ‐ENaC compared to NSD. Mathematical modelling predicted that tubular Na+ reabsorption increased in the proximal tubule but decreased in the distal nephron because of diminished Na+ delivery. This prediction was confirmed by the natriuretic response to diuretics targeting the thick ascending limb, the distal convoluted tubule or the collecting system. On the other hand, HSD did not alter measured GFR but decreased the abundance of the aforementioned transporters compared to NSD. Mathematical modelling predicted that tubular Na+ reabsorption decreased in the proximal tubule but increased in distal segments with lower transport efficiency with respect to O2 consumption. This prediction was confirmed by the natriuretic response to diuretics. The activity of the metabolic sensor adenosine monophosphate‐activated protein kinase (AMPK) was related to the changes in tubular Na+ reabsorption. Our data show that fractional Na+ reabsorption is distributed differently according to dietary Na+ intake and induces changes in tubular O2 consumption and sodium transport efficiency. Body Na+ content is tightly controlled by regulated urinary Na+ excretion. The intrarenal mechanisms mediating adaptation to variations in dietary Na+ intake are incompletely characterized. We confirmed and expanded observations in mice that variations in dietary Na+ intake do not alter the glomerular filtration rate but alter the total and cell‐surface expression of major Na+ transporters all along the kidney tubule. Low dietary Na+ intake increased Na+ reabsorption in the proximal tubule and decreased it in more distal kidney tubule segments. High dietary Na+ intake decreased Na+ reabsorption in the proximal tubule and increased it in distal segments with lower energetic efficiency. The abundance of apical transporters and Na+ delivery are the main determinants of Na+ reabsorption along the kidney tubule. Tubular O2 consumption and the efficiency of sodium reabsorption are dependent on sodium diet.
Collapse
Affiliation(s)
- Khalil Udwan
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, 1 Rue Michel-Servet, CH-1211, Geneva 4, Switzerland.,National Centre of Competence in Research, NCCRKidney, CH, Switzerland
| | - Ahmed Abed
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, 1 Rue Michel-Servet, CH-1211, Geneva 4, Switzerland.,National Centre of Competence in Research, NCCRKidney, CH, Switzerland
| | - Isabelle Roth
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, 1 Rue Michel-Servet, CH-1211, Geneva 4, Switzerland
| | - Eva Dizin
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, 1 Rue Michel-Servet, CH-1211, Geneva 4, Switzerland.,National Centre of Competence in Research, NCCRKidney, CH, Switzerland
| | - Marc Maillard
- Centre hospitalier universitaire Vaudois, Service de néphrologie, CH-1011, Lausanne, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Johannes Loffing
- Institute of Anatomy, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.,National Centre of Competence in Research, NCCRKidney, CH, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.,National Centre of Competence in Research, NCCRKidney, CH, Switzerland
| | - Aurélie Edwards
- Centre de Recherche des Cordeliers, INSERM UMRS1138 and CNRS ERL8228, 15 rue de l'Ecole de Médecine, F-75006, Paris, France.,Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Eric Feraille
- Department of Cellular Physiology and Metabolism, University of Geneva, CMU, 1 Rue Michel-Servet, CH-1211, Geneva 4, Switzerland.,National Centre of Competence in Research, NCCRKidney, CH, Switzerland
| |
Collapse
|
31
|
Ernandez T, Udwan K, Chassot A, Martin PY, Feraille E. Uninephrectomy and apical fluid shear stress decrease ENaC abundance in collecting duct principal cells. Am J Physiol Renal Physiol 2017; 314:F763-F772. [PMID: 28877879 DOI: 10.1152/ajprenal.00200.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute nephron reduction such as after living kidney donation may increase the risk of hypertension. Uninephrectomy induces major hemodynamic changes in the remaining kidney, resulting in rapid increase of single-nephron glomerular filtration rate (GFR) and fluid delivery in the distal nephron. Decreased sodium (Na) fractional reabsorption after the distal tubule has been reported after uninephrectomy in animals preserving volume homeostasis. In the present study, we thought to specifically explore the effect of unilateral nephrectomy on epithelial Na channel (ENaC) subunit expression in mice. We show that γ-ENaC subunit surface expression was specifically downregulated after uninephrectomy, whereas the expression of the aldosterone-sensitive α-ENaC and α1-Na-K-ATPase subunits as well as of kidney-specific Na-K-Cl cotransporter isoform and Na-Cl cotransporter were not significantly altered. Because acute nephron reduction induces a rapid increase of single-nephron GFR, resulting in a higher tubular fluid flow, we speculated that local mechanical factors such as fluid shear stress (FSS) were involved in Na reabsorption regulation after uninephrectomy. We further explore such hypothesis in an in vitro model of FSS applied on highly differentiated collecting duct principal cells. We found that FSS specifically downregulates β-ENaC and γ-ENaC subunits at the transcriptional level through an unidentified heat-insensitive paracrine basolateral factor. The primary cilium as a potential mechanosensor was not required. In contrast, protein kinase A and calcium-sensitive cytosolic phospholipase A2 were involved, but we could not demonstrate a role for cyclooxygenase or epoxygenase metabolites.
Collapse
Affiliation(s)
- T Ernandez
- Service of Nephrology, University Hospital of Geneva , Geneva , Switzerland.,Department of Cell Physiology and Metabolism, University Medical Center , Geneva , Switzerland
| | - K Udwan
- Department of Cell Physiology and Metabolism, University Medical Center , Geneva , Switzerland
| | - A Chassot
- Department of Cell Physiology and Metabolism, University Medical Center , Geneva , Switzerland
| | - P-Y Martin
- Service of Nephrology, University Hospital of Geneva , Geneva , Switzerland
| | - E Feraille
- Department of Cell Physiology and Metabolism, University Medical Center , Geneva , Switzerland
| |
Collapse
|
32
|
Knöpfel T, Atanassoff A, Hernando N, Biber J, Wagner CA. Renal localization and regulation by dietary phosphate of the MCT14 orphan transporter. PLoS One 2017; 12:e0177942. [PMID: 28662032 PMCID: PMC5490967 DOI: 10.1371/journal.pone.0177942] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 05/05/2017] [Indexed: 01/15/2023] Open
Abstract
MCT14 is an orphan transporter belonging to the SLC16 transporter family mediating the transport of monocarboxylates, aromatic amino acids, creatine, and thyroid hormones. The expression, tissue localization, regulation, and function of MCT14 are unknown. In mouse MCT14 mRNA abundance is highest in kidney. Using a newly developed and validated antibody, MCT14 was localized to the luminal membrane of the thick ascending limb of the loop of Henle colocalizing in the same cells with uromodulin and NKCC2. MCT14 mRNA and protein was found to be highly regulated by dietary phosphate intake in mice being increased by high dietary phosphate intake at both mRNA and protein level. In order to identify the transport substrate(s), we expressed MCT14 in Xenopus laevis oocytes where MCT14 was integrated into the plasma membrane. However, no transport was discovered for the classic substrates of the SLC16 family nor for phosphate. In summary, MCT14 is an orphan transporter regulated by phosphate and highly enriched in kidney localizing to the luminal membrane of one specific nephron segment.
Collapse
Affiliation(s)
- Thomas Knöpfel
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Alexander Atanassoff
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Jürg Biber
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Carsten A. Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
- * E-mail:
| |
Collapse
|
33
|
Wynne BM, Mistry AC, Al-Khalili O, Mallick R, Theilig F, Eaton DC, Hoover RS. Aldosterone Modulates the Association between NCC and ENaC. Sci Rep 2017. [PMID: 28646163 PMCID: PMC5482882 DOI: 10.1038/s41598-017-03510-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Distal sodium transport is a final step in the regulation of blood pressure. As such, understanding how the two main sodium transport proteins, the thiazide-sensitive sodium chloride cotransporter (NCC) and the epithelial sodium channel (ENaC), are regulated is paramount. Both are expressed in the late distal nephron; however, no evidence has suggested that these two sodium transport proteins interact. Recently, we established that these two sodium transport proteins functionally interact in the second part of the distal nephron (DCT2). Given their co-localization within the DCT2, we hypothesized that NCC and ENaC interactions might be modulated by aldosterone (Aldo). Aldo treatment increased NCC and αENaC colocalization (electron microscopy) and interaction (coimmunoprecipitation). Finally, with co-expression of the Aldo-induced protein serum- and glucocorticoid-inducible kinase 1 (SGK1), NCC and αENaC interactions were increased. These data demonstrate that Aldo promotes increased interaction of NCC and ENaC, within the DCT2 revealing a novel method of regulation for distal sodium reabsorption.
Collapse
Affiliation(s)
- Brandi M Wynne
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA, 30322, USA. .,Center for Cell and Molecular Signaling, Emory University, Atlanta, GA, 30322, USA.
| | - Abinash C Mistry
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Otor Al-Khalili
- Department of Physiology, Emory University, Atlanta, GA, 30322, USA
| | - Rickta Mallick
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Franziska Theilig
- Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Douglas C Eaton
- Department of Physiology, Emory University, Atlanta, GA, 30322, USA.,Center for Cell and Molecular Signaling, Emory University, Atlanta, GA, 30322, USA
| | - Robert S Hoover
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, GA, 30322, USA.,Department of Physiology, Emory University, Atlanta, GA, 30322, USA.,Research Service, Atlanta Veteran's Administration Medical Center, Decatur, GA, 30033, USA
| |
Collapse
|
34
|
Boscardin E, Perrier R, Sergi C, Maillard M, Loffing J, Loffing-Cueni D, Koesters R, Rossier BC, Hummler E. Severe hyperkalemia is rescued by low-potassium diet in renal βENaC-deficient mice. Pflugers Arch 2017; 469:1387-1399. [DOI: 10.1007/s00424-017-1990-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 04/07/2017] [Accepted: 04/26/2017] [Indexed: 12/31/2022]
|
35
|
Harlander S, Schönenberger D, Toussaint NC, Prummer M, Catalano A, Brandt L, Moch H, Wild PJ, Frew IJ. Combined mutation in Vhl, Trp53 and Rb1 causes clear cell renal cell carcinoma in mice. Nat Med 2017; 23:869-877. [PMID: 28553932 PMCID: PMC5509015 DOI: 10.1038/nm.4343] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 04/15/2017] [Indexed: 12/17/2022]
Abstract
Clear cell renal cell carcinomas (ccRCC) frequently exhibit inactivation of the VHL tumour suppressor gene and often harbour multiple copy number alterations in genes that regulate cell cycle progression. We show here that modelling these genetic alterations by combined renal epithelium-specific deletion of Vhl, Trp53 and Rb1 in mice caused ccRCC. These tumours arose from proximal tubule epithelial cells and shared molecular markers and mRNA expression profiles with human ccRCC. Exome sequencing revealed that mouse and human ccRCCs exhibit recurrent mutations in genes associated with the primary cilium, uncovering a mutational convergence on this organelle and implicating a subset of ccRCCs as genetic ciliopathies. Different mouse tumours responded differently to standard therapies for advanced human ccRCC, mimicking the range of clinical behaviours in the human disease. Inhibition of HIF-α transcription factors with Acriflavine as third line therapy had therapeutic effects in some tumours, providing pre-clinical evidence for further investigation of HIF-α inhibition as a ccRCC treatment. This autochthonous mouse ccRCC model represents a tool to investigate the biology of ccRCC and to identify new treatment strategies.
Collapse
Affiliation(s)
- Sabine Harlander
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | | | - Nora C Toussaint
- NEXUS Personalized Health Technologies, ETH Zurich, Zurich, Switzerland.,SIB Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Michael Prummer
- NEXUS Personalized Health Technologies, ETH Zurich, Zurich, Switzerland.,SIB Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Antonella Catalano
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,Center for Translational Cell Research, Clinic of Internal Medicine I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Laura Brandt
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Holger Moch
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Peter J Wild
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Ian J Frew
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,Center for Translational Cell Research, Clinic of Internal Medicine I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| |
Collapse
|
36
|
Tokonami N, Cheval L, Monnay I, Meurice G, Loffing J, Feraille E, Houillier P. Endothelin-1 mediates natriuresis but not polyuria during vitamin D-induced acute hypercalcaemia. J Physiol 2017; 595:2535-2550. [PMID: 28120456 DOI: 10.1113/jp273610] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/16/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Hypercalcaemia can occur under various pathological conditions, such as primary hyperparathyroidism, malignancy or granulomatosis, and it induces natriuresis and polyuria in various species via an unknown mechanism. A previous study demonstrated that hypercalcaemia induced by vitamin D in rats increased endothelin (ET)-1 expression in the distal nephron, which suggests the involvement of the ET system in hypercalcaemia-induced effects. In the present study, we demonstrate that, during vitamin D-induced hypercalcaemia, the activation of ET system by increased ET-1 is responsible for natriuresis but not for polyuria. Vitamin D-treated hypercalcaemic mice showed a blunted response to amiloride, suggesting that epithelial sodium channel function is inhibited. We have identified an original pathway that specifically mediates the effects of vitamin D-induced hypercalcaemia on sodium handling in the distal nephron without affecting water handling. ABSTRACT Acute hypercalcaemia increases urinary sodium and water excretion; however, the underlying molecular mechanism remains unclear. Because vitamin D-induced hypercalcaemia increases the renal expression of endothelin (ET)-1, we hypothesized that ET-1 mediates the effects of hypercalcaemia on renal sodium and water handling. Hypercalcaemia was induced in 8-week-old, parathyroid hormone-supplemented, male mice by oral administration of dihydrotachysterol (DHT) for 3 days. DHT-treated mice became hypercalcaemic and displayed increased urinary water and sodium excretion compared to controls. mRNA levels of ET-1 and the transcription factors CCAAT-enhancer binding protein β and δ were specifically increased in the distal convoluted tubule and downstream segments in DHT-treated mice. To examine the role of the ET system in hypercalcaemia-induced natriuresis and polyuria, mice were treated with the ET-1 receptor antagonist macitentan, with or without DHT. Mice treated with both macitentan and DHT displayed hypercalcaemia and polyuria similar to that in mice treated with DHT alone; however, no increase in urinary sodium excretion was observed. To identify the affected sodium transport mechanism, we assessed the response to various diuretics in control and DHT-treated hypercalcaemic mice. Amiloride, an inhibitor of the epithelial sodium channel (ENaC), increased sodium excretion to a lesser extent in DHT-treated mice compared to control mice. Mice treated with either macitentan+DHT or macitentan alone had a similar response to amiloride. In summary, vitamin D-induced hypercalcaemia increases the renal production of ET-1 and decreases ENaC activity, which is probably responsible for the rise in urinary sodium excretion but not for polyuria.
Collapse
Affiliation(s)
- Natsuko Tokonami
- Sorbonne Université, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138 team 3, Centre de Recherche des Cordeliers, CNRS ERL 8228, Paris, France
| | - Lydie Cheval
- Sorbonne Université, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138 team 3, Centre de Recherche des Cordeliers, CNRS ERL 8228, Paris, France
| | - Isabelle Monnay
- University of Geneva, Department of Cell Physiology and Metabolism, Service of Nephrology University Medical Center, Geneva, Switzerland
| | - Guillaume Meurice
- Bioinformatic Core Facility, UMS AMMICA, INSERM US23, CNRS UMS3665, Gustave Roussy, Villejuif, France
| | | | - Eric Feraille
- University of Geneva, Department of Cell Physiology and Metabolism, Service of Nephrology University Medical Center, Geneva, Switzerland
| | - Pascal Houillier
- Sorbonne Université, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138 team 3, Centre de Recherche des Cordeliers, CNRS ERL 8228, Paris, France
| |
Collapse
|
37
|
Penton D, Czogalla J, Wengi A, Himmerkus N, Loffing-Cueni D, Carrel M, Rajaram RD, Staub O, Bleich M, Schweda F, Loffing J. Extracellular K + rapidly controls NaCl cotransporter phosphorylation in the native distal convoluted tubule by Cl - -dependent and independent mechanisms. J Physiol 2016; 594:6319-6331. [PMID: 27457700 DOI: 10.1113/jp272504] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/14/2016] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS High dietary potassium (K+ ) intake dephosphorylates and inactivates the NaCl cotransporter (NCC) in the renal distal convoluted tubule (DCT). Using several ex vivo models, we show that physiological changes in extracellular K+ , similar to those occurring after a K+ rich diet, are sufficient to promote a very rapid dephosphorylation of NCC in native DCT cells. Although the increase of NCC phosphorylation upon decreased extracellular K+ appears to depend on cellular Cl- fluxes, the rapid NCC dephosphorylation in response to increased extracellular K+ is not Cl- -dependent. The Cl- -dependent pathway involves the SPAK/OSR1 kinases, whereas the Cl- independent pathway may include additional signalling cascades. ABSTRACT A high dietary potassium (K+ ) intake causes a rapid dephosphorylation, and hence inactivation, of the thiazide-sensitive NaCl cotransporter (NCC) in the renal distal convoluted tubule (DCT). Based on experiments in heterologous expression systems, it was proposed that changes in extracellular K+ concentration ([K+ ]ex ) modulate NCC phosphorylation via a Cl- -dependent modulation of the with no lysine (K) kinases (WNK)-STE20/SPS-1-44 related proline-alanine-rich protein kinase (SPAK)/oxidative stress-related kinase (OSR1) kinase pathway. We used the isolated perfused mouse kidney technique and ex vivo preparations of mouse kidney slices to test the physiological relevance of this model on native DCT. We demonstrate that NCC phosphorylation inversely correlates with [K+ ]ex , with the most prominent effects occurring around physiological plasma [K+ ]. Cellular Cl- conductances and the kinases SPAK/OSR1 are involved in the phosphorylation of NCC under low [K+ ]ex . However, NCC dephosphorylation triggered by high [K+ ]ex is neither blocked by removing extracellular Cl- , nor by the Cl- channel blocker 4,4'-diisothiocyano-2,2'-stilbenedisulphonic acid. The response to [K+ ]ex on a low extracellular chloride concentration is also independent of significant changes in SPAK/OSR1 phosphorylation. Thus, in the native DCT, [K+ ]ex directly and rapidly controls NCC phosphorylation by Cl- -dependent and independent pathways that involve the kinases SPAK/OSR1 and a yet unidentified additional signalling mechanism.
Collapse
Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre of Competence in Research 'Kidney Control of Homeostasis', University of Zurich, Zurich, Switzerland
| | - Jan Czogalla
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre of Competence in Research 'Kidney Control of Homeostasis', University of Zurich, Zurich, Switzerland
| | - Agnieszka Wengi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrecht University, Kiel, Germany
| | | | - Monique Carrel
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Renuga Devi Rajaram
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,Swiss National Centre of Competence in Research 'Kidney Control of Homeostasis', University of Zurich, Zurich, Switzerland
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,Swiss National Centre of Competence in Research 'Kidney Control of Homeostasis', University of Zurich, Zurich, Switzerland
| | - Markus Bleich
- Institute of Physiology, Christian-Albrecht University, Kiel, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland. .,Swiss National Centre of Competence in Research 'Kidney Control of Homeostasis', University of Zurich, Zurich, Switzerland.
| |
Collapse
|
38
|
Soleimani M, Barone S, Xu J, Alshahrani S, Brooks M, McCormack FX, Smith RD, Zahedi K. Prostaglandin-E2 Mediated Increase in Calcium and Phosphate Excretion in a Mouse Model of Distal Nephron Salt Wasting. PLoS One 2016; 11:e0159804. [PMID: 27442254 PMCID: PMC4956050 DOI: 10.1371/journal.pone.0159804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 07/10/2016] [Indexed: 01/29/2023] Open
Abstract
Contribution of salt wasting and volume depletion to the pathogenesis of hypercalciuria and hyperphosphaturia is poorly understood. Pendrin/NCC double KO (pendrin/NCC-dKO) mice display severe salt wasting under basal conditions and develop profound volume depletion, prerenal renal failure, and metabolic alkalosis and are growth retarded. Microscopic examination of the kidneys of pendrin/NCC-dKO mice revealed the presence of calcium phosphate deposits in the medullary collecting ducts, along with increased urinary calcium and phosphate excretion. Confirmatory studies revealed decreases in the expression levels of sodium phosphate transporter-2 isoforms a and c, increases in the expression of cytochrome p450 family 4a isotypes 12 a and b, as well as prostaglandin E synthase 1, and cyclooxygenases 1 and 2. Pendrin/NCC-dKO animals also had a significant increase in urinary prostaglandin E2 (PGE-2) and renal content of 20-hydroxyeicosatetraenoic acid (20-HETE) levels. Pendrin/NCC-dKO animals exhibit reduced expression levels of the sodium/potassium/2chloride co-transporter 2 (NKCC2) in their medullary thick ascending limb. Further assessment of the renal expression of NKCC2 isoforms by quantitative real time PCR (qRT-PCR) reveled that compared to WT mice, the expression of NKCC2 isotype F was significantly reduced in pendrin/NCC-dKO mice. Provision of a high salt diet to rectify volume depletion or inhibition of PGE-2 synthesis by indomethacin, but not inhibition of 20-HETE generation by HET0016, significantly improved hypercalciuria and salt wasting in pendrin/NCC dKO mice. Both high salt diet and indomethacin treatment also corrected the alterations in NKCC2 isotype expression in pendrin/NCC-dKO mice. We propose that severe salt wasting and volume depletion, irrespective of the primary originating nephron segment, can secondarily impair the reabsorption of salt and calcium in the thick ascending limb of Henle and/or proximal tubule, and reabsorption of sodium and phosphate in the proximal tubule via processes that are mediated by PGE-2.
Collapse
Affiliation(s)
- Manoocher Soleimani
- Center on Genetics of Transport, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Departments of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Research Services, Veterans Affairs Medical Center, Cincinnati, OH, United States of America
- * E-mail:
| | - Sharon Barone
- Center on Genetics of Transport, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Departments of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Research Services, Veterans Affairs Medical Center, Cincinnati, OH, United States of America
| | - Jie Xu
- Center on Genetics of Transport, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Departments of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
| | - Saeed Alshahrani
- Department of Pharmacology and Cell Biophysics and, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
| | - Marybeth Brooks
- Center on Genetics of Transport, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Departments of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
| | - Francis X. McCormack
- Departments of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
| | - Roger D. Smith
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
| | - Kamyar Zahedi
- Center on Genetics of Transport, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Departments of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Research Services, Veterans Affairs Medical Center, Cincinnati, OH, United States of America
| |
Collapse
|
39
|
The sodium chloride cotransporter (NCC) and epithelial sodium channel (ENaC) associate. Biochem J 2016; 473:3237-52. [PMID: 27422782 DOI: 10.1042/bcj20160312] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/11/2016] [Indexed: 11/17/2022]
Abstract
The thiazide-sensitive sodium chloride cotransporter (NCC) and the epithelial sodium channel (ENaC) are two of the most important determinants of salt balance and thus systemic blood pressure. Abnormalities in either result in profound changes in blood pressure. There is one segment of the nephron where these two sodium transporters are coexpressed, the second part of the distal convoluted tubule. This is a key part of the aldosterone-sensitive distal nephron, the final regulator of salt handling in the kidney. Aldosterone is the key hormonal regulator for both of these proteins. Despite these shared regulators and coexpression in a key nephron segment, associations between these proteins have not been investigated. After confirming apical localization of these proteins, we demonstrated the presence of functional transport proteins and native association by blue native PAGE. Extensive coimmunoprecipitation experiments demonstrated a consistent interaction of NCC with α- and γ-ENaC. Mammalian two-hybrid studies demonstrated direct binding of NCC to ENaC subunits. Fluorescence resonance energy transfer and immunogold EM studies confirmed that these transport proteins are within appropriate proximity for direct binding. Additionally, we demonstrate that there are functional consequences of this interaction, with inhibition of NCC affecting the function of ENaC. This novel finding of an association between ENaC and NCC could alter our understanding of salt transport in the distal tubule.
Collapse
|
40
|
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.
Collapse
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
| |
Collapse
|
41
|
Czogalla J, Vohra T, Penton D, Kirschmann M, Craigie E, Loffing J. The mineralocorticoid receptor (MR) regulates ENaC but not NCC in mice with random MR deletion. Pflugers Arch 2016; 468:849-58. [PMID: 26898302 DOI: 10.1007/s00424-016-1798-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/03/2016] [Accepted: 02/08/2016] [Indexed: 12/13/2022]
Abstract
Aldosterone binds to the mineralocorticoid receptor (MR) and increases renal Na(+) reabsorption via up-regulation of the epithelial Na(+) channel (ENaC) and the Na(+)-K(+)-ATPase in the collecting system (CS) and possibly also via the NaCl cotransporter (NCC) in the distal convoluted tubule (DCT). However, whether aldosterone directly regulates NCC via MR or indirectly through systemic alterations remains controversial. We used mice with deletion of MR in ∼20 % of renal tubule cells (MR/X mice), in which MR-positive (MR(wt)) and -negative (MR(ko)) cells can be studied side-by-side in the same physiological context. Adult MR/X mice showed similar mRNA and protein levels of renal ion transport proteins to control mice. In MR/X mice, no differences in NCC abundance and phosphorylation was seen between MR(wt) and MR(ko) cells and dietary Na(+) restriction up-regulated NCC to similar extent in both groups of cells. In contrast, MR(ko) cells in the CS did not show any detectable alpha-ENaC abundance or apical targeting of ENaC neither on control diet nor in response to dietary Na(+) restriction. Furthermore, Na(+)-K(+)-ATPase expression was unaffected in MR(ko) cells of the DCT, while it was lost in MR(ko) cells of the CS. In conclusion, MR is crucial for ENaC and Na(+)-K(+)-ATPase regulation in the CS, but is dispensable for NCC and Na(+)-K(+)-ATPase regulation in the DCT.
Collapse
Affiliation(s)
- Jan Czogalla
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland
| | - Twinkle Vohra
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - David Penton
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland
| | - Moritz Kirschmann
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Eilidh Craigie
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland. .,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland.
| |
Collapse
|
42
|
Daryadel A, Bourgeois S, Figueiredo MFL, Gomes Moreira A, Kampik NB, Oberli L, Mohebbi N, Lu X, Meima ME, Danser AHJ, Wagner CA. Colocalization of the (Pro)renin Receptor/Atp6ap2 with H+-ATPases in Mouse Kidney but Prorenin Does Not Acutely Regulate Intercalated Cell H+-ATPase Activity. PLoS One 2016; 11:e0147831. [PMID: 26824839 PMCID: PMC4732657 DOI: 10.1371/journal.pone.0147831] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 01/08/2016] [Indexed: 12/11/2022] Open
Abstract
The (Pro)renin receptor (P)RR/Atp6ap2 is a cell surface protein capable of binding and non-proteolytically activate prorenin. Additionally, (P)RR is associated with H+-ATPases and alternative functions in H+-ATPase regulation as well as in Wnt signalling have been reported. Kidneys express very high levels of H+-ATPases which are involved in multiple functions such as endocytosis, membrane protein recycling as well as urinary acidification, bicarbonate reabsorption, and salt absorption. Here, we wanted to localize the (P)RR/Atp6ap2 along the murine nephron, exmaine whether the (P)RR/Atp6ap2 is coregulated with other H+-ATPase subunits, and whether acute stimulation of the (P)RR/Atp6ap2 with prorenin regulates H+-ATPase activity in intercalated cells in freshly isolated collecting ducts. We localized (P)PR/Atp6ap2 along the murine nephron by qPCR and immunohistochemistry. (P)RR/Atp6ap2 mRNA was detected in all nephron segments with highest levels in the collecting system coinciding with H+-ATPases. Further experiments demonstrated expression at the brush border membrane of proximal tubules and in all types of intercalated cells colocalizing with H+-ATPases. In mice treated with NH4Cl, NaHCO3, KHCO3, NaCl, or the mineralocorticoid DOCA for 7 days, (P)RR/Atp6ap2 and H+-ATPase subunits were regulated but not co-regulated at protein and mRNA levels. Immunolocalization in kidneys from control, NH4Cl or NaHCO3 treated mice demonstrated always colocalization of PRR/Atp6ap2 with H+-ATPase subunits at the brush border membrane of proximal tubules, the apical pole of type A intercalated cells, and at basolateral and/or apical membranes of non-type A intercalated cells. Microperfusion of isolated cortical collecting ducts and luminal application of prorenin did not acutely stimulate H+-ATPase activity. However, incubation of isolated collecting ducts with prorenin non-significantly increased ERK1/2 phosphorylation. Our results suggest that the PRR/Atp6ap2 may form a complex with H+-ATPases in proximal tubule and intercalated cells but that prorenin has no acute effect on H+-ATPase activity in intercalated cells.
Collapse
MESH Headings
- Ammonium Chloride/pharmacology
- Animals
- Anion Transport Proteins/genetics
- Anion Transport Proteins/metabolism
- Aquaporin 2/genetics
- Aquaporin 2/metabolism
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Dogs
- Gene Expression Regulation
- Kidney Cortex/cytology
- Kidney Cortex/drug effects
- Kidney Cortex/metabolism
- Kidney Medulla/cytology
- Kidney Medulla/drug effects
- Kidney Medulla/metabolism
- Kidney Tubules, Collecting/cytology
- Kidney Tubules, Collecting/drug effects
- Kidney Tubules, Collecting/metabolism
- Kidney Tubules, Proximal/cytology
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Madin Darby Canine Kidney Cells
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Mice
- Mice, Inbred C57BL
- Proton-Translocating ATPases/genetics
- Proton-Translocating ATPases/metabolism
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Renin/pharmacology
- Renin-Angiotensin System/drug effects
- Signal Transduction
- Sodium Bicarbonate/pharmacology
- Sodium Chloride/pharmacology
- Sodium-Phosphate Cotransporter Proteins, Type IIa/genetics
- Sodium-Phosphate Cotransporter Proteins, Type IIa/metabolism
- Solute Carrier Family 12, Member 1/genetics
- Solute Carrier Family 12, Member 1/metabolism
- Solute Carrier Family 12, Member 3/genetics
- Solute Carrier Family 12, Member 3/metabolism
- Sulfate Transporters
Collapse
Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Soline Bourgeois
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | | | | | - Nicole B. Kampik
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Lisa Oberli
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Nilufar Mohebbi
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- Divison of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Xifeng Lu
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marcel E. Meima
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - A. H. Jan Danser
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Carsten A. Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- * E-mail:
| |
Collapse
|
43
|
Dong K, Yan Q, Lu M, Wan L, Hu H, Guo J, Boulpaep E, Wang W, Giebisch G, Hebert SC, Wang T. Romk1 Knockout Mice Do Not Produce Bartter Phenotype but Exhibit Impaired K Excretion. J Biol Chem 2016; 291:5259-69. [PMID: 26728465 DOI: 10.1074/jbc.m115.707877] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Indexed: 01/05/2023] Open
Abstract
Romk knock-out mice show a similar phenotype to Bartter syndrome of salt wasting and dehydration due to reduced Na-K-2Cl-cotransporter activity. At least three ROMK isoforms have been identified in the kidney; however, unique functions of any of the isoforms in nephron segments are still poorly understood. We have generated a mouse deficient only in Romk1 by selective deletion of the Romk1-specific first exon using an ES cell Cre-LoxP strategy and examined the renal phenotypes, ion transporter expression, ROMK channel activity, and localization under normal and high K intake. Unlike Romk(-/-) mice, there was no Bartter phenotype with reduced NKCC2 activity and increased NCC expression in Romk1(-/-) mice. The small conductance K channel (SK) activity showed no difference of channel properties or gating in the collecting tubule between Romk1(+/+) and Romk1(-/-) mice. High K intake increased SK channel number per patch and increased the ROMK channel intensity in the apical membrane of the collecting tubule in Romk1(+/+), but such regulation by high K intake was diminished with significant hyperkalemia in Romk1(-/-) mice. We conclude that 1) animal knockouts of ROMK1 do not produce Bartter phenotype. 2) There is no functional linking of ROMK1 and NKCC2 in the TAL. 3) ROMK1 is critical in response to high K intake-stimulated K(+) secretion in the collecting tubule.
Collapse
Affiliation(s)
- Ke Dong
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Qingshang Yan
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Ming Lu
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Laxiang Wan
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Haiyan Hu
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Junhua Guo
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Emile Boulpaep
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - WenHui Wang
- the Department of Pharmacology, New York Medical College, Valhalla, New York 10595
| | - Gerhard Giebisch
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Steven C Hebert
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Tong Wang
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| |
Collapse
|
44
|
Perrier R, Boscardin E, Malsure S, Sergi C, Maillard MP, Loffing J, Loffing-Cueni D, Sørensen MV, Koesters R, Rossier BC, Frateschi S, Hummler E. Severe Salt-Losing Syndrome and Hyperkalemia Induced by Adult Nephron-Specific Knockout of the Epithelial Sodium Channel α-Subunit. J Am Soc Nephrol 2015; 27:2309-18. [PMID: 26701978 DOI: 10.1681/asn.2015020154] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 10/28/2015] [Indexed: 11/03/2022] Open
Abstract
Systemic pseudohypoaldosteronism type 1 (PHA-1) is a severe salt-losing syndrome caused by loss-of-function mutations of the amiloride-sensitive epithelial sodium channel (ENaC) and characterized by neonatal life-threatening hypovolemia and hyperkalemia. The very high plasma aldosterone levels detected under hypovolemic or hyperkalemic challenge can lead to increased or decreased sodium reabsorption, respectively, through the Na(+)/Cl(-) cotransporter (NCC). However, the role of ENaC deficiency remains incompletely defined, because constitutive inactivation of individual ENaC subunits is neonatally lethal in mice. We generated adult inducible nephron-specific αENaC-knockout mice (Scnn1a(Pax8/LC1)) that exhibit hyperkalemia and body weight loss when kept on a regular-salt diet, thus mimicking PHA-1. Compared with control mice fed a regular-salt diet, knockout mice fed a regular-salt diet exhibited downregulated expression and phosphorylation of NCC protein, despite high plasma aldosterone levels. In knockout mice fed a high-sodium and reduced-potassium diet (rescue diet), although plasma aldosterone levels remained significantly increased, NCC expression returned to control levels, and body weight, plasma and urinary electrolyte concentrations, and excretion normalized. Finally, shift to a regular diet after the rescue diet reinstated the symptoms of severe PHA-1 syndrome and significantly reduced NCC phosphorylation. In conclusion, lack of ENaC-mediated sodium transport along the nephron cannot be compensated for by other sodium channels and/or transporters, only by a high-sodium and reduced-potassium diet. We further conclude that hyperkalemia becomes the determining factor in regulating NCC activity, regardless of sodium loss, in the ENaC-mediated salt-losing PHA-1 phenotype.
Collapse
Affiliation(s)
- Romain Perrier
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Emilie Boscardin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Swiss National Center of Competence in Research "Kidney.CH", Zurich, Switzerland
| | - Sumedha Malsure
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Chloé Sergi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Marc P Maillard
- Service of Nephrology Department, University Hospital of Lausanne, Lausanne, Switzerland
| | - Johannes Loffing
- Swiss National Center of Competence in Research "Kidney.CH", Zurich, Switzerland; Institute of Anatomy, University of Zurich, Zurich, Switzerland; and
| | - Dominique Loffing-Cueni
- Swiss National Center of Competence in Research "Kidney.CH", Zurich, Switzerland; Institute of Anatomy, University of Zurich, Zurich, Switzerland; and
| | - Mads Vaarby Sørensen
- Swiss National Center of Competence in Research "Kidney.CH", Zurich, Switzerland; Institute of Anatomy, University of Zurich, Zurich, Switzerland; and
| | - Robert Koesters
- Department of Nephrology, Hôpital Tenon, Université Pierre et Marie Curie, Paris, France
| | - Bernard C Rossier
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland;
| | - Simona Frateschi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Swiss National Center of Competence in Research "Kidney.CH", Zurich, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Swiss National Center of Competence in Research "Kidney.CH", Zurich, Switzerland;
| |
Collapse
|
45
|
de Groot T, Sinke AP, Kortenoeven MLA, Alsady M, Baumgarten R, Devuyst O, Loffing J, Wetzels JF, Deen PMT. Acetazolamide Attenuates Lithium-Induced Nephrogenic Diabetes Insipidus. J Am Soc Nephrol 2015; 27:2082-91. [PMID: 26574046 DOI: 10.1681/asn.2015070796] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 09/30/2015] [Indexed: 12/27/2022] Open
Abstract
To reduce lithium-induced nephrogenic diabetes insipidus (lithium-NDI), patients with bipolar disorder are treated with thiazide and amiloride, which are thought to induce antidiuresis by a compensatory increase in prourine uptake in proximal tubules. However, thiazides induced antidiuresis and alkalinized the urine in lithium-NDI mice lacking the sodium-chloride cotransporter, suggesting that inhibition of carbonic anhydrases (CAs) confers the beneficial thiazide effect. Therefore, we tested the effect of the CA-specific blocker acetazolamide in lithium-NDI. In collecting duct (mpkCCD) cells, acetazolamide reduced the cellular lithium content and attenuated lithium-induced downregulation of aquaporin-2 through a mechanism different from that of amiloride. Treatment of lithium-NDI mice with acetazolamide or thiazide/amiloride induced similar antidiuresis and increased urine osmolality and aquaporin-2 abundance. Thiazide/amiloride-treated mice showed hyponatremia, hyperkalemia, hypercalcemia, metabolic acidosis, and increased serum lithium concentrations, adverse effects previously observed in patients but not in acetazolamide-treated mice in this study. Furthermore, acetazolamide treatment reduced inulin clearance and cortical expression of sodium/hydrogen exchanger 3 and attenuated the increased expression of urinary PGE2 observed in lithium-NDI mice. These results show that the antidiuresis with acetazolamide was partially caused by a tubular-glomerular feedback response and reduced GFR. The tubular-glomerular feedback response and/or direct effect on collecting duct principal or intercalated cells may underlie the reduced urinary PGE2 levels with acetazolamide, thereby contributing to the attenuation of lithium-NDI. In conclusion, CA activity contributes to lithium-NDI development, and acetazolamide attenuates lithium-NDI development in mice similar to thiazide/amiloride but with fewer adverse effects.
Collapse
Affiliation(s)
| | | | | | | | | | - Olivier Devuyst
- Institute of Physiology, Zurich Centre for Integrative Human Physiology, Zurich, Switzerland; and
| | | | - Jack F Wetzels
- Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | |
Collapse
|
46
|
Ellison DH, Terker AS, Gamba G. Potassium and Its Discontents: New Insight, New Treatments. J Am Soc Nephrol 2015; 27:981-9. [PMID: 26510885 DOI: 10.1681/asn.2015070751] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Hyperkalemia is common in patients with impaired kidney function or who take drugs that inhibit the renin-angiotensin-aldosterone axis. During the past decade, substantial advances in understanding how the body controls potassium excretion have been made, which may lead to improved standard of care for these patients. Renal potassium disposition is primarily handled by a short segment of the nephron, comprising part of the distal convoluted tubule and the connecting tubule, and regulation results from the interplay between aldosterone and plasma potassium. When dietary potassium intake and plasma potassium are low, the electroneutral sodium chloride cotransporter is activated, leading to salt retention. This effect limits sodium delivery to potassium secretory segments, limiting potassium losses. In contrast, when dietary potassium intake is high, aldosterone is stimulated. Simultaneously, potassium inhibits the sodium chloride cotransporter. Because more sodium is then delivered to potassium secretory segments, primed by aldosterone, kaliuresis results. When these processes are disrupted, hyperkalemia results. Recently, new agents capable of removing potassium from the body and treating hyperkalemia have been tested in clinical trials. This development suggests that more effective and safer approaches to the prevention and treatment of hyperkalemia may be on the horizon.
Collapse
Affiliation(s)
- David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon; Renal Section, Veterans Affairs Portland Health Care System, Portland, Oregon; and
| | - Andrew S Terker
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| |
Collapse
|
47
|
Di Chiara M, Glaudemans B, Loffing-Cueni D, Odermatt A, Al-Hasani H, Devuyst O, Faresse N, Loffing J. Rab-GAP TBC1D4 (AS160) is dispensable for the renal control of sodium and water homeostasis but regulates GLUT4 in mouse kidney. Am J Physiol Renal Physiol 2015; 309:F779-90. [PMID: 26336159 DOI: 10.1152/ajprenal.00139.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 08/29/2015] [Indexed: 12/17/2022] Open
Abstract
The Rab GTPase-activating protein TBC1D4 (AS160) controls trafficking of the glucose transporter GLUT4 in adipocytes and skeletal muscle cells. TBC1D4 is also highly abundant in the renal distal tubule, although its role in this tubule is so far unknown. In vitro studies suggest that it is involved in the regulation of renal transporters and channels such as the epithelial sodium channel (ENaC), aquaporin-2 (AQP2), and the Na+-K+-ATPase. To assess the physiological role of TBC1D4 in the kidney, wild-type (TBC1D4+/+) and TBC1D4-deficient (TBC1D4-/-) mice were studied. Unexpectedly, neither under standard nor under challenging conditions (low Na+/high K+, water restriction) did TBC1D4-/- mice show any difference in urinary Na+ and K+ excretion, urine osmolarity, plasma ion and aldosterone levels, and blood pressure compared with TBC1D4+/+ mice. Also, immunoblotting did not reveal any change in the abundance of major renal sodium- and water-transporting proteins [Na-K-2Cl cotransporter (NKCC2) NKCC2, NaCl cotransporter (NCC), ENaC, AQP2, and the Na+-K+-ATPase]. However, the abundance of GLUT4, which colocalizes with TBC1D4 along the distal nephron of TBC1D4+/+ mice, was lower in whole kidney lysates of TBC1D4-/- mice than in TBC1D4+/+ mice. Likewise, primary thick ascending limb (TAL) cells isolated from TBC1D4-/- mice showed an increased basal glucose uptake and an abrogated insulin response compared with TAL cells from TBC1D4+/+ mice. Thus, TBC1D4 is dispensable for the regulation of renal Na+ and water transport, but may play a role for GLUT4-mediated basolateral glucose uptake in distal tubules. The latter may contribute to the known anaerobic glycolytic capacity of distal tubules during renal ischemia.
Collapse
Affiliation(s)
- Marianna Di Chiara
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Bob Glaudemans
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | | | - Alex Odermatt
- Division of Molecular and Systems Toxicology, Pharmacenter, University of Basel, Basel, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
| | - Hadi Al-Hasani
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University and German Center for Diabetes Research, Düsseldorf, Germany
| | - Olivier Devuyst
- Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland; Institute of Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
| | - Nourdine Faresse
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
| |
Collapse
|
48
|
Hunter RW, Ivy JR, Flatman PW, Kenyon CJ, Craigie E, Mullins LJ, Bailey MA, Mullins JJ. Hypertrophy in the Distal Convoluted Tubule of an 11β-Hydroxysteroid Dehydrogenase Type 2 Knockout Model. J Am Soc Nephrol 2015; 26:1537-48. [PMID: 25349206 PMCID: PMC4483573 DOI: 10.1681/asn.2013060634] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 08/12/2014] [Indexed: 11/03/2022] Open
Abstract
Na(+) transport in the renal distal convoluted tubule (DCT) by the thiazide-sensitive NaCl cotransporter (NCC) is a major determinant of total body Na(+) and BP. NCC-mediated transport is stimulated by aldosterone, the dominant regulator of chronic Na(+) homeostasis, but the mechanism is controversial. Transport may also be affected by epithelial remodeling, which occurs in the DCT in response to chronic perturbations in electrolyte homeostasis. Hsd11b2(-/-) mice, which lack the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) and thus exhibit the syndrome of apparent mineralocorticoid excess, provided an ideal model in which to investigate the potential for DCT hypertrophy to contribute to Na(+) retention in a hypertensive condition. The DCTs of Hsd11b2(-/-) mice exhibited hypertrophy and hyperplasia and the kidneys expressed higher levels of total and phosphorylated NCC compared with those of wild-type mice. However, the striking structural and molecular phenotypes were not associated with an increase in the natriuretic effect of thiazide. In wild-type mice, Hsd11b2 mRNA was detected in some tubule segments expressing Slc12a3, but 11βHSD2 and NCC did not colocalize at the protein level. Thus, the phosphorylation status of NCC may not necessarily equate to its activity in vivo, and the structural remodeling of the DCT in the knockout mouse may not be a direct consequence of aberrant corticosteroid signaling in DCT cells. These observations suggest that the conventional concept of mineralocorticoid signaling in the DCT should be revised to recognize the complexity of NCC regulation by corticosteroids.
Collapse
Affiliation(s)
- Robert W Hunter
- British Heart Foundation Centre for Cardiovascular Science and
| | - Jessica R Ivy
- British Heart Foundation Centre for Cardiovascular Science and
| | - Peter W Flatman
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Eilidh Craigie
- British Heart Foundation Centre for Cardiovascular Science and
| | - Linda J Mullins
- British Heart Foundation Centre for Cardiovascular Science and
| | | | - John J Mullins
- British Heart Foundation Centre for Cardiovascular Science and
| |
Collapse
|
49
|
Mordasini D, Loffing-Cueni D, Loffing J, Beatrice R, Maillard MP, Hummler E, Burnier M, Escher G, Vogt B. ENaC activity in collecting ducts modulates NCC in cirrhotic mice. Pflugers Arch 2015; 467:2529-39. [PMID: 26055235 DOI: 10.1007/s00424-015-1711-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/24/2015] [Accepted: 05/18/2015] [Indexed: 01/07/2023]
Abstract
Cirrhosis is a frequent and severe disease, complicated by renal sodium retention leading to ascites and oedema. A better understanding of the complex mechanisms responsible for renal sodium handling could improve clinical management of sodium retention. Our aim was to determine the importance of the amiloride-sensitive epithelial sodium channel (ENaC) in collecting ducts in compensate and decompensate cirrhosis. Bile duct ligation was performed in control mice (CTL) and collecting duct-specific αENaC knockout (KO) mice, and ascites development, aldosterone plasma concentration, urinary sodium/potassium ratio and sodium transporter expression were compared. Disruption of ENaC in collecting ducts (CDs) did not alter ascites development, urinary sodium/potassium ratio, plasma aldosterone concentrations or Na,K-ATPase abundance in CCDs. Total αENaC abundance in whole kidney increased in cirrhotic mice of both genotypes and cleaved forms of α and γ ENaC increased only in ascitic mice of both genotypes. The sodium chloride cotransporter (NCC) abundance was lower in non-ascitic KO, compared to non-ascitic CTL, and increased when ascites appeared. In ascitic mice, the lack of αENaC in CDs induced an upregulation of total ENaC and NCC and correlated with the cleavage of ENaC subunits. This revealed compensatory mechanisms which could also take place when treating the patients with diuretics. These compensatory mechanisms should be considered for future development of therapeutic strategies.
Collapse
Affiliation(s)
- David Mordasini
- Department of Nephrology, Hypertension and Clinical Pharmacology, Inselspital, Bern University Hospital, Bern, Switzerland. .,Department of Clinical Research, University of Bern, Bern, Switzerland.
| | | | | | - Rohrbach Beatrice
- Department of Nephrology, Hypertension and Clinical Pharmacology, Inselspital, Bern University Hospital, Bern, Switzerland.,Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Marc P Maillard
- Service of Nephrology and Hypertension, CHUV, Rue du Bugnon 17, CH-1005, Lausanne, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Rue du Bugnon 27, CH-1005, Lausanne, Switzerland
| | - Michel Burnier
- Service of Nephrology and Hypertension, CHUV, Rue du Bugnon 17, CH-1005, Lausanne, Switzerland
| | - Geneviève Escher
- Department of Nephrology, Hypertension and Clinical Pharmacology, Inselspital, Bern University Hospital, Bern, Switzerland.,Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Bruno Vogt
- Department of Nephrology, Hypertension and Clinical Pharmacology, Inselspital, Bern University Hospital, Bern, Switzerland.,Department of Clinical Research, University of Bern, Bern, Switzerland
| |
Collapse
|
50
|
Guetg A, Mariotta L, Bock L, Herzog B, Fingerhut R, Camargo SMR, Verrey F. Essential amino acid transporter Lat4 (Slc43a2) is required for mouse development. J Physiol 2015; 593:1273-89. [PMID: 25480797 DOI: 10.1113/jphysiol.2014.283960] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 11/25/2014] [Indexed: 12/23/2022] Open
Abstract
Amino acid (AA) uniporter Lat4 (Slc43a2) mediates facilitated diffusion of branched-chain AAs, methionine and phenylalanine, although its physiological role and subcellular localization are not known. We report that Slc43a2 knockout mice were born at expected Mendelian frequency but displayed an ∼10% intrauterine growth retardation and low amniotic fluid AAs, suggesting defective transplacental transport. Postnatal growth was strongly reduced, with premature death occurring within 9 days such that further investigations were made within 3 days of birth. Lat4 immunofluorescence showed a strong basolateral signal in the small intestine, kidney proximal tubule and thick ascending limb epithelial cells of wild-type but not Slc43a2 null littermates and no signal in liver and skeletal muscle. Experiments using Xenopus laevis oocytes demonstrated that Lat4 functioned as a symmetrical low affinity uniporter with a K₀.₅ of ∼5 mm for both in- and efflux. Plasma AA concentration was decreased in Slc43a2 null pups, in particular that of non-essential AAs alanine, serine, histidine and proline. Together with an increased level of plasma long chain acylcarnitines and a strong alteration of liver gene expression, this indicates malnutrition. Attempts to rescue pups by decreasing the litter size or by nutrients injected i.p. did not succeed. Radioactively labelled leucine but not lysine given per os accumulated in the small intestine of Slc43a2null pups, suggesting the defective transcellular transport of Lat4 substrates. In summary, Lat4 is a symmetrical uniporter for neutral essential AAs localizing at the basolateral side of (re)absorbing epithelia and is necessary for early nutrition and development.
Collapse
Affiliation(s)
- Adriano Guetg
- Institute of Physiology and Zurich Center of Integrative Human Physiology, University of Zurich, Switzerland
| | | | | | | | | | | | | |
Collapse
|