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Fenton RA, Ellison DH. 2024 Carl W. Gottschalk Distinguished Lectureship of the American Physiological Society Renal Section. Am J Physiol Renal Physiol 2024; 326:F855-F856. [PMID: 38545649 DOI: 10.1152/ajprenal.00086.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 03/19/2024] [Indexed: 05/04/2024] Open
Affiliation(s)
- Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - David H Ellison
- Division of Nephrology and Hypertension, School of Medicine, Oregon Health and Science University, Portland, Oregon, United States
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Welling PA, Little R, Al-Qusairi L, Delpire E, Ellison DH, Fenton RA, Grimm PR. Potassium-Switch Signaling Pathway Dictates Acute Blood Pressure Response to Dietary Potassium. Hypertension 2024; 81:1044-1054. [PMID: 38465625 PMCID: PMC11023808 DOI: 10.1161/hypertensionaha.123.22546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/27/2024] [Indexed: 03/12/2024]
Abstract
BACKGROUND Potassium (K+)-deficient diets, typical of modern processed foods, increase blood pressure (BP) and NaCl sensitivity. A K+-dependent signaling pathway in the kidney distal convoluted tubule, coined the K+ switch, that couples extracellular K+ sensing to activation of the thiazide-sensitive NaCl cotransporter (NCC) and NaCl retention has been implicated, but causality has not been established. METHODS To test the hypothesis that small, physiological changes in plasma K+ (PK+) are translated to BP through the switch pathway, a genetic approach was used to activate the downstream switch kinase, SPAK (SPS1-related proline/alanine-rich kinase), within the distal convoluted tubule. The CA-SPAK (constitutively active SPS1-related proline/alanine-rich kinase mice) were compared with control mice over a 4-day PK+ titration (3.8-5.1 mmol) induced by changes in dietary K+. Arterial BP was monitored using radiotelemetry, and renal function measurements, NCC abundance, phosphorylation, and activity were made. RESULTS As PK+ decreased in control mice, BP progressively increased and became sensitive to dietary NaCl and hydrochlorothiazide, coincident with increased NCC phosphorylation and urinary sodium retention. By contrast, BP in CA-SPAK mice was elevated, resistant to the PK+ titration, and sensitive to hydrochlorothiazide and salt at all PK+ levels, concomitant with sustained and elevated urinary sodium retention and NCC phosphorylation and activity. Thus, genetically locking the switch on drives NaCl sensitivity and prevents the response of BP to potassium. CONCLUSIONS Low K+, common in modern ultraprocessed diets, presses the K+-switch pathway to turn on NCC activity, increasing sodium retention, BP, and salt sensitivity.
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Affiliation(s)
- Paul A. Welling
- Department of Medicine, Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Robert Little
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Lama Al-Qusairi
- Department of Medicine, Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, USA
| | - David H. Ellison
- Department of Medicine, Division of Nephrology, Oregon Health Science Center, Portland, Oregon, US
| | - Robert A. Fenton
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - P. Richard Grimm
- Department of Medicine, Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, USA
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Murali SK, McCormick JA, Fenton RA. Regulation of the water channel aquaporin-2 by cullin E3 ubiquitin ligases. Am J Physiol Renal Physiol 2024; 326:F814-F826. [PMID: 38545647 DOI: 10.1152/ajprenal.00049.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/15/2024] [Accepted: 03/15/2024] [Indexed: 05/04/2024] Open
Abstract
Aquaporin 2 (AQP2) is a vasopressin (VP)-regulated water channel in the renal collecting duct. Phosphorylation and ubiquitylation of AQP2 play an essential role in controlling the cellular abundance of AQP2 and its accumulation on the plasma membrane in response to VP. Cullin-RING ubiquitin ligases (CRLs) are multisubunit E3 ligases involved in ubiquitylation and degradation of their target proteins, eight of which are expressed in the collecting duct. Here, we used an established cell model of the collecting duct (mpkCCD14 cells) to study the role of cullins in modulating AQP2. Western blotting identified Cul-1 to Cul-5 in mpkCCD14 cells. Treatment of cells for 4 h with a pan-cullin inhibitor (MLN4924) decreased AQP2 abundance, prevented a VP-induced reduction in AQP2 Ser261 phosphorylation, and attenuated VP-induced plasma membrane accumulation of AQP2 relative to the vehicle. AQP2 ubiquitylation levels were significantly higher after MLN4924 treatment compared with controls, and they remained higher despite VP treatment. Cullin inhibition increased ERK1/2 activity, a kinase that regulates AQP2 Ser261 phosphorylation, and VP-induced reductions in ERK1/2 phosphorylation were absent during MLN4924 treatment. Furthermore, the greater Ser261 phosphorylation and reduction in AQP2 abundance during MLN4924 treatment were attenuated during ERK1/2 inhibition. MLN4924 increased intracellular calcium levels via calcium release-activated calcium channels, inhibition of which abolished MLN4924 effects on Ser261 phosphorylation and AQP2 abundance. In conclusion, CRLs play a vital role in mediating some of the effects of VP to increase AQP2 plasma membrane accumulation and AQP2 abundance. Whether modulation of cullin activity can contribute to body water homeostasis requires further studies.NEW & NOTEWORTHY Aquaporin 2 (AQP2) is essential for body water homeostasis and is regulated by the antidiuretic hormone vasopressin. The posttranslational modification ubiquitylation is a key regulator of AQP2 abundance and plasma membrane localization. Here we demonstrate that cullin-RING E3 ligases play a vital role in mediating some of the effects of vasopressin to increase AQP2 abundance and plasma membrane accumulation. The results suggest that manipulating cullin activity could be a novel strategy to alter kidney water handling.
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Affiliation(s)
- Sathish K Murali
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - James A McCormick
- Department of Medicine, Oregon Health and Science University, Portland, Oregon, United States
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Billing AM, Kim YC, Gullaksen S, Schrage B, Raabe J, Hutzfeldt A, Demir F, Kovalenko E, Lassé M, Dugourd A, Fallegger R, Klampe B, Jaegers J, Li Q, Kravtsova O, Crespo-Masip M, Palermo A, Fenton RA, Hoxha E, Blankenberg S, Kirchhof P, Huber TB, Laugesen E, Zeller T, Chrysopoulou M, Saez-Rodriguez J, Magnussen C, Eschenhagen T, Staruschenko A, Siuzdak G, Poulsen PL, Schwab C, Cuello F, Vallon V, Rinschen MM. Metabolic Communication by SGLT2 Inhibition. Circulation 2024; 149:860-884. [PMID: 38152989 PMCID: PMC10922673 DOI: 10.1161/circulationaha.123.065517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 11/22/2023] [Indexed: 12/29/2023]
Abstract
BACKGROUND SGLT2 (sodium-glucose cotransporter 2) inhibitors (SGLT2i) can protect the kidneys and heart, but the underlying mechanism remains poorly understood. METHODS To gain insights on primary effects of SGLT2i that are not confounded by pathophysiologic processes or are secondary to improvement by SGLT2i, we performed an in-depth proteomics, phosphoproteomics, and metabolomics analysis by integrating signatures from multiple metabolic organs and body fluids after 1 week of SGLT2i treatment of nondiabetic as well as diabetic mice with early and uncomplicated hyperglycemia. RESULTS Kidneys of nondiabetic mice reacted most strongly to SGLT2i in terms of proteomic reconfiguration, including evidence for less early proximal tubule glucotoxicity and a broad downregulation of the apical uptake transport machinery (including sodium, glucose, urate, purine bases, and amino acids), supported by mouse and human SGLT2 interactome studies. SGLT2i affected heart and liver signaling, but more reactive organs included the white adipose tissue, showing more lipolysis, and, particularly, the gut microbiome, with a lower relative abundance of bacteria taxa capable of fermenting phenylalanine and tryptophan to cardiovascular uremic toxins, resulting in lower plasma levels of these compounds (including p-cresol sulfate). SGLT2i was detectable in murine stool samples and its addition to human stool microbiota fermentation recapitulated some murine microbiome findings, suggesting direct inhibition of fermentation of aromatic amino acids and tryptophan. In mice lacking SGLT2 and in patients with decompensated heart failure or diabetes, the SGLT2i likewise reduced circulating p-cresol sulfate, and p-cresol impaired contractility and rhythm in human induced pluripotent stem cell-derived engineered heart tissue. CONCLUSIONS SGLT2i reduced microbiome formation of uremic toxins such as p-cresol sulfate and thereby their body exposure and need for renal detoxification, which, combined with direct kidney effects of SGLT2i, including less proximal tubule glucotoxicity and a broad downregulation of apical transporters (including sodium, amino acid, and urate uptake), provides a metabolic foundation for kidney and cardiovascular protection.
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Affiliation(s)
- Anja M. Billing
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Young Chul Kim
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla (Y.C.K., M.C.-M., V.V.)
- VA San Diego Healthcare System, CA (Y.C.K., M.C.-M., V.V.)
| | - Søren Gullaksen
- Clinical Medicine (S.G., P.L.P.), Aarhus University, Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark (S.G., E.L.)
| | - Benedikt Schrage
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Janice Raabe
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Arvid Hutzfeldt
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Fatih Demir
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Elina Kovalenko
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Moritz Lassé
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Aurelien Dugourd
- Heidelberg University, Faculty of Medicine, and Heidelberg University Hospital, Institute for Computational Biomedicine, BioQuant, Heidelberg, Germany (A.D., R.F., J.S.-R.)
| | - Robin Fallegger
- Heidelberg University, Faculty of Medicine, and Heidelberg University Hospital, Institute for Computational Biomedicine, BioQuant, Heidelberg, Germany (A.D., R.F., J.S.-R.)
| | - Birgit Klampe
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Johannes Jaegers
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Qing Li
- Engineering (Q.L., C.S.), Aarhus University, Denmark
| | - Olha Kravtsova
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Maria Crespo-Masip
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla (Y.C.K., M.C.-M., V.V.)
- VA San Diego Healthcare System, CA (Y.C.K., M.C.-M., V.V.)
| | - Amelia Palermo
- Scripps Research, Center for Metabolomics, San Diego, CA (A.P., G.S., M.M.R.)
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles (A.P.)
| | - Robert A. Fenton
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Elion Hoxha
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Stefan Blankenberg
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Paulus Kirchhof
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Cardiovascular Sciences, University of Birmingham, United Kingdom (P.K.)
| | - Tobias B. Huber
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Esben Laugesen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark (S.G., E.L.)
- Diagnostic Centre, Silkeborg Regional Hospital, Denmark (E.L.)
| | - Tanja Zeller
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Maria Chrysopoulou
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Julio Saez-Rodriguez
- Heidelberg University, Faculty of Medicine, and Heidelberg University Hospital, Institute for Computational Biomedicine, BioQuant, Heidelberg, Germany (A.D., R.F., J.S.-R.)
| | - Christina Magnussen
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Thomas Eschenhagen
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa (O.K., A.S.)
| | - Gary Siuzdak
- Scripps Research, Center for Metabolomics, San Diego, CA (A.P., G.S., M.M.R.)
| | - Per L. Poulsen
- Clinical Medicine (S.G., P.L.P.), Aarhus University, Denmark
- Steno Diabetes Center (P.L.P.), Aarhus University, Denmark
| | | | - Friederike Cuello
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla (Y.C.K., M.C.-M., V.V.)
- VA San Diego Healthcare System, CA (Y.C.K., M.C.-M., V.V.)
| | - Markus M. Rinschen
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
- Aarhus Institute of Advanced Studies (M.M.R.), Aarhus University, Denmark
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
- Scripps Research, Center for Metabolomics, San Diego, CA (A.P., G.S., M.M.R.)
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van der Horst D, Kurmasheva N, Marqvorsen MHS, Assil S, Rahimic AHF, Kollmann CF, Silva da Costa L, Wu Q, Zhao J, Cesari E, Iversen MB, Ren F, Jensen TI, Narita R, Schack VR, Zhang BC, Bak RO, Sette C, Fenton RA, Mikkelsen JG, Paludan SR, Olagnier D. SAM68 directs STING signaling to apoptosis in macrophages. Commun Biol 2024; 7:283. [PMID: 38454028 PMCID: PMC10920828 DOI: 10.1038/s42003-024-05969-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 02/23/2024] [Indexed: 03/09/2024] Open
Abstract
DNA is a danger signal sensed by cGAS to engage signaling through STING to activate innate immune functions. The best-studied downstream responses to STING activation include expression of type I interferon and inflammatory genes, but STING also activates other pathways, including apoptosis. Here, we report that STING-dependent induction of apoptosis in macrophages occurs through the intrinsic mitochondrial pathway and is mediated via IRF3 but acts independently of gene transcription. By intersecting four mass spectrometry datasets, we identify SAM68 as crucial for the induction of apoptosis downstream of STING activation. SAM68 is essential for the full activation of apoptosis. Still, it is not required for STING-mediated activation of IFN expression or activation of NF-κB. Mechanistic studies reveal that protein trafficking is required and involves SAM68 recruitment to STING upon activation, with the two proteins associating at the Golgi or a post-Golgi compartment. Collectively, our work identifies SAM68 as a STING-interacting protein enabling induction of apoptosis through this DNA-activated innate immune pathway.
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Affiliation(s)
- Demi van der Horst
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Naziia Kurmasheva
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Mikkel H S Marqvorsen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Sonia Assil
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Anna H F Rahimic
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Christoph F Kollmann
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Leandro Silva da Costa
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Qi Wu
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Jian Zhao
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Eleonora Cesari
- GSTEP-Organoids Core Facility, IRCCS Fondazione Policlinico Agostino Gemelli, 00168, Rome, Italy
| | - Marie B Iversen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Fanghui Ren
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Trine I Jensen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Ryo Narita
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Vivien R Schack
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Bao-Cun Zhang
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Rasmus O Bak
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Claudio Sette
- GSTEP-Organoids Core Facility, IRCCS Fondazione Policlinico Agostino Gemelli, 00168, Rome, Italy
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, 00168, Rome, Italy
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Jacob G Mikkelsen
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark
| | - Søren R Paludan
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark.
| | - David Olagnier
- Department of Biomedicine, Aarhus University, Høegh Guldbergsgade 10, 8000, Aarhus C, Denmark.
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Brooks HL, de Castro Brás LE, Brunt KR, Sylvester MA, Parvatiyar MS, Sirish P, Bansal SS, Sule R, Eadie AL, Knepper MA, Fenton RA, Lindsey ML, DeLeon-Pennell KY, Gomes AV. Guidelines on antibody use in physiology research. Am J Physiol Renal Physiol 2024; 326:F511-F533. [PMID: 38234298 DOI: 10.1152/ajprenal.00347.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/19/2024] Open
Abstract
Antibodies are one of the most used reagents in scientific laboratories and are critical components for a multitude of experiments in physiology research. Over the past decade, concerns about many biological methods, including those that use antibodies, have arisen as several laboratories were unable to reproduce the scientific data obtained in other laboratories. The lack of reproducibility could be largely attributed to inadequate reporting of detailed methods, no or limited verification by authors, and the production and use of unvalidated antibodies. The goal of this guideline article is to review best practices concerning commonly used techniques involving antibodies, including immunoblotting, immunohistochemistry, and flow cytometry. Awareness and integration of best practices will increase the rigor and reproducibility of these techniques and elevate the quality of physiology research.
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Affiliation(s)
- Heddwen L Brooks
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana, United States
| | | | - Keith R Brunt
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Saint John, New Brunswick, Canada
| | - Megan A Sylvester
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona, United States
| | - Michelle S Parvatiyar
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, Florida, United States
| | - Padmini Sirish
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, California, United States
| | - Shyam S Bansal
- Department of Cellular and Molecular Physiology, Heart and Vascular Institute, Pennsylvania State University Hershey Medical Center, Hershey, Pennsylvania, United States
| | - Rasheed Sule
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, United States
| | - Ashley L Eadie
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Saint John, New Brunswick, Canada
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Merry L Lindsey
- School of Graduate Studies, Meharry Medical College, Nashville, Tennessee, United States
- Research Service, Nashville Veterans Affairs Medical Center, Nashville, Tennessee, United States
| | - Kristine Y DeLeon-Pennell
- Division of Cardiology, Department of Medicine, School of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
- Research Service, Ralph H Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, United States
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7
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Geurts F, Chaker L, van der Burgh AC, Cronin‐Fenton D, Fenton RA, Hoorn EJ. Urinary Prostaglandin E2 Excretion and the Risk of Cardiovascular and Kidney Disease. J Am Heart Assoc 2024; 13:e032835. [PMID: 38362883 PMCID: PMC11010119 DOI: 10.1161/jaha.123.032835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024]
Abstract
BACKGROUND Inhibition of prostaglandin synthesis by nonsteroidal anti-inflammatory drugs is associated with cardiovascular mortality and kidney disease. This study hypothesizes that urinary prostaglandin E2 (PGE2) and PGE2 metabolite (PGEM) excretions are markers of cardiovascular and kidney health, because they reflect both systemic and kidney-derived PGE2 production. METHODS AND RESULTS PGE2 and PGEM were measured in spot urine samples from 2291 participants (≥55 years old) of the population-based Rotterdam Study. Urinary PGE2 and PGEM excretions were analyzed using linear regression analyses to identify cross-sectional associations with cardiovascular risk factors and baseline estimated glomerular filtration rate (eGFR). Longitudinal associations with cardiovascular mortality and kidney outcomes (eGFR <60 or <45 mL/min per 1.73 m2 and the composite outcome 40% eGFR loss or kidney failure) were assessed with Cox regression. Urinary PGE2 and PGEM excretions were higher with increasing age, lower eGFR, smoking, diabetes, and albuminuria. A 2-fold higher urinary PGE2 and PGEM excretion was associated with a higher risk of cardiovascular mortality (28 825 patient-years; 160 events; PGE2 hazard ratio [HR], 1.27, [95% CI, 1.06-1.54]; PGEM HR, 1.36 [95% CI, 1.10-1.67]). Higher PGE2 excretions were also associated with a higher risk of incident eGFR <60 mL/min per 1.73 m2 (31 530 person-years; 691 events; HR, 1.13 [95% CI, 1.02-1.25]) with similar HRs for the other kidney outcomes. CONCLUSIONS Urinary PGE2 and PGEM excretions are novel markers for the presence and progression of cardiovascular and kidney disease. Future studies should address whether these associations are causal and can be targeted to improve cardiovascular and kidney outcomes.
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Affiliation(s)
- Frank Geurts
- Department of Internal Medicine, Erasmus Medical CenterUniversity Medical Center RotterdamRotterdamThe Netherlands
- Department of Epidemiology, Erasmus Medical CenterUniversity Medical Center RotterdamRotterdamThe Netherlands
| | - Layal Chaker
- Department of Internal Medicine, Erasmus Medical CenterUniversity Medical Center RotterdamRotterdamThe Netherlands
- Department of Epidemiology, Erasmus Medical CenterUniversity Medical Center RotterdamRotterdamThe Netherlands
| | - Anna C. van der Burgh
- Department of Epidemiology, Erasmus Medical CenterUniversity Medical Center RotterdamRotterdamThe Netherlands
| | - Deirdre Cronin‐Fenton
- Department of Clinical Epidemiology, Department of Clinical MedicineAarhus University Hospital and Aarhus UniversityAarhusDenmark
| | | | - Ewout J. Hoorn
- Department of Internal Medicine, Erasmus Medical CenterUniversity Medical Center RotterdamRotterdamThe Netherlands
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8
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Pluznick JL, Fenton RA. Perspective on G protein-coupled receptors in renal physiology. Am J Physiol Renal Physiol 2023; 325:F683-F684. [PMID: 37823197 DOI: 10.1152/ajprenal.00307.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 10/13/2023] Open
Affiliation(s)
- Jennifer L Pluznick
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Robert A Fenton
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
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9
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Grimm PR, Tatomir A, Rosenbaek LL, Kim BY, Li D, Delpire EJ, Fenton RA, Welling PA. Dietary potassium stimulates Ppp1Ca-Ppp1r1a dephosphorylation of kidney NaCl cotransporter and reduces blood pressure. J Clin Invest 2023; 133:e158498. [PMID: 37676724 PMCID: PMC10617769 DOI: 10.1172/jci158498] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 09/06/2023] [Indexed: 09/09/2023] Open
Abstract
Consumption of low dietary potassium, common with ultraprocessed foods, activates the thiazide-sensitive sodium chloride cotransporter (NCC) via the with no (K) lysine kinase/STE20/SPS1-related proline-alanine-rich protein kinase (WNK/SPAK) pathway to induce salt retention and elevate blood pressure (BP). However, it remains unclear how high-potassium "DASH-like" diets (dietary approaches to stop hypertension) inactivate the cotransporter and whether this decreases BP. A transcriptomics screen identified Ppp1Ca, encoding PP1A, as a potassium-upregulated gene, and its negative regulator Ppp1r1a, as a potassium-suppressed gene in the kidney. PP1A directly binds to and dephosphorylates NCC when extracellular potassium is elevated. Using mice genetically engineered to constitutively activate the NCC-regulatory kinase SPAK and thereby eliminate the effects of the WNK/SPAK kinase cascade, we confirmed that PP1A dephosphorylated NCC directly in a potassium-regulated manner. Prior adaptation to a high-potassium diet was required to maximally dephosphorylate NCC and lower BP in constitutively active SPAK mice, and this was associated with potassium-dependent suppression of Ppp1r1a and dephosphorylation of its cognate protein, inhibitory subunit 1 (I1). In conclusion, potassium-dependent activation of PP1A and inhibition of I1 drove NCC dephosphorylation, providing a mechanism to explain how high dietary K+ lowers BP. Shifting signaling of PP1A in favor of activation of WNK/SPAK may provide an improved therapeutic approach for treating salt-sensitive hypertension.
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Affiliation(s)
- P. Richard Grimm
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
| | - Anamaria Tatomir
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Lena L. Rosenbaek
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Bo Young Kim
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
| | - Dimin Li
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Eric J. Delpire
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennssee, USA
| | - Robert A. Fenton
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Paul A. Welling
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Physiology, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
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10
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Geurts F, Xue L, Kramers BJ, Zietse R, Gansevoort RT, Fenton RA, Meijer E, Salih M, Hoorn EJ. Prostaglandin E2, Osmoregulation, and Disease Progression in Autosomal Dominant Polycystic Kidney Disease. Clin J Am Soc Nephrol 2023; 18:1426-1434. [PMID: 37574650 PMCID: PMC10637469 DOI: 10.2215/cjn.0000000000000269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/06/2023] [Indexed: 08/15/2023]
Abstract
BACKGROUND Prostaglandin E2 (PGE2) plays a physiological role in osmoregulation, a process that is affected early in autosomal dominant polycystic kidney disease (ADPKD). PGE2 has also been implicated in the pathogenesis of ADPKD in preclinical models, but human data are limited. Here, we hypothesized that urinary PGE2 excretion is associated with impaired osmoregulation, disease severity, and disease progression in human ADPKD. METHODS Urinary excretions of PGE2 and its metabolite (PGEM) were measured in a prospective cohort of patients with ADPKD. The associations between urinary PGE2 and PGEM excretions, markers of osmoregulation, eGFR and height-adjusted total kidney volume were assessed using linear regression models. Cox regression and linear mixed models were used for the longitudinal analysis of the associations between urinary PGE2 and PGEM excretions and disease progression defined as 40% eGFR loss or kidney failure, and change in eGFR over time. In two intervention studies, we quantified the effect of starting tolvaptan and adding hydrochlorothiazide to tolvaptan on urinary PGE2 and PGEM excretions. RESULTS In 562 patients with ADPKD (61% female, eGFR 63±28 ml/min per 1.73 m 2 ), higher urinary PGE2 or PGEM excretions were independently associated with higher plasma copeptin, lower urine osmolality, lower eGFR, and greater total kidney volume. Participants with higher baseline urinary PGE2 and PGEM excretions had a higher risk of 40% eGFR loss or kidney failure (hazard ratio, 1.28; 95% confidence interval [CI], 1.13 to 1.46 and hazard ratio, 1.50; 95% CI, 1.26 to 1.80 per two-fold higher urinary PGE2 or PGEM excretions) and a faster change in eGFR over time (-0.39 [95% CI, -0.59 to -0.20] and -0.53 [95% CI, -0.75 to -0.31] ml/min per 1.73 m 2 per year). In the intervention studies, urinary PGEM excretion was higher after starting tolvaptan, while urinary PGE2 excretion was higher after adding hydrochlorothiazide to tolvaptan. CONCLUSIONS Higher urinary PGE2 and PGEM excretions in patients with ADPKD are associated with impaired osmoregulation, disease severity, and progression.
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Affiliation(s)
- Frank Geurts
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Laixi Xue
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Bart J. Kramers
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Robert Zietse
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Ron T. Gansevoort
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | | | - Esther Meijer
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Mahdi Salih
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Ewout J. Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
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11
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Little R, Murali SK, Poulsen SB, Grimm PR, Assmus A, Cheng L, Ivy JR, Hoorn EJ, Matchkov V, Welling PA, Fenton RA. Dissociation of sodium-chloride cotransporter expression and blood pressure during chronic high dietary potassium supplementation. JCI Insight 2023; 8:156437. [PMID: 36719746 PMCID: PMC10077486 DOI: 10.1172/jci.insight.156437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
Dietary potassium (K+) supplementation is associated with a lowering effect in blood pressure (BP), but not all studies agree. Here, we examined the effects of short- and long-term K+ supplementation on BP in mice, whether differences depend on the accompanying anion or the sodium (Na+) intake and molecular alterations in the kidney that may underlie BP changes. Relative to the control diet, BP was higher in mice fed a high NaCl (1.57% Na+) diet for 7 weeks or fed a K+-free diet for 2 weeks. BP was highest on a K+-free/high NaCl diet. Commensurate with increased abundance and phosphorylation of the thiazide sensitive sodium-chloride-cotransporter (NCC) on the K+-free/high NaCl diet, BP returned to normal with thiazides. Three weeks of a high K+ diet (5% K+) increased BP (predominantly during the night) independently of dietary Na+ or anion intake. Conversely, 4 days of KCl feeding reduced BP. Both feeding periods resulted in lower NCC levels but in increased levels of cleaved (active) α and γ subunits of the epithelial Na+ channel ENaC. The elevated BP after chronic K+ feeding was reduced by amiloride but not thiazide. Our results suggest that dietary K+ has an optimal threshold where it may be most effective for cardiovascular health.
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Affiliation(s)
- Robert Little
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Søren B Poulsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Paul R Grimm
- Departments of Medicine, Nephrology and Physiology, Johns Hopkins School of Medicine, Baltimore, USA
| | - Adrienne Assmus
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Lei Cheng
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jessica R Ivy
- University/BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ewout J Hoorn
- Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | | | - Paul A Welling
- Departments of Medicine, Nephrology and Physiology, Johns Hopkins School of Medicine, Baltimore, USA
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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12
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Wu A, Wolley MJ, Mayr HL, Cheng L, Cowley D, Li B, Campbell KL, Terker AS, Ellison DH, Welling PA, Fenton RA, Stowasser M. Randomized trial on the effect of oral potassium chloride supplementation on the thiazide-sensitive sodium chloride cotransporter in healthy adults. Kidney Int Rep 2023. [DOI: 10.1016/j.ekir.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
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13
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Petrillo F, Chernyakov D, Esteva-Font C, Poulsen SB, Edemir B, Fenton RA. Genetic deletion of the nuclear factor of activated T cells 5 in collecting duct principal cells causes nephrogenic diabetes insipidus. FASEB J 2022; 36:e22583. [PMID: 36197017 DOI: 10.1096/fj.202200856r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/24/2022] [Accepted: 09/20/2022] [Indexed: 11/11/2022]
Abstract
Water homeostasis is tightly regulated by the kidneys via the process of urine concentration. During reduced water intake, the antidiuretic hormone arginine vasopressin (AVP) binds to the vasopressin receptor type II (V2R) in the kidney to enhance countercurrent multiplication and medullary osmolality, and increase water reabsorption via aquaporin-2 (AQP2) water channels. The importance of this AVP, V2R, and AQP2 axis is highlighted by low urine osmolality and polyuria in people with various water balance disorders, including nephrogenic diabetes insipidus (NDI). ELF5 and nuclear factor of activated T cells 5 (NFAT5) are two transcription factors proposed to regulate Aqp2 expression, but their role is poorly defined. Here we generated two novel mouse lines with principal cell (PC)-specific deletion of ELF5 or NFAT5 and phenotyped them in respect to renal water handling. ELF5-deficient mice (ELF5PC-KO ) had a very mild phenotype, with no clear differences in AQP2 abundance, and mild differences in renal water handling and maximal urinary concentrating capacity. In contrast, NFAT5 (NFAT5PC-KO ) mice had significantly higher water intake and their 24 h urine volume was almost 10-fold greater than controls. After challenging with dDAVP or 8 h water restriction, NFAT5PC-KO mice were unable to concentrate their urine, demonstrating that they suffer from NDI. The abundance of AQP2, other AQPs, and the urea transporter UT-A1 were greatly decreased in NFAT5PC-KO mice. In conclusion, NFAT5 is a major regulator of not only Aqp2 gene transcription, but also other genes important for water homeostasis and its absence leads to the development of NDI.
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Affiliation(s)
| | - Dmitry Chernyakov
- Department of Medicine, Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | | | - Søren B Poulsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Bayram Edemir
- Department of Medicine, Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.,Institute for Physiology, Pathophysiology and Toxicology, Witten/Herdecke University, Witten, Germany
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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14
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Neumann C, Rosenbæk LL, Flygaard RK, Habeck M, Karlsen JL, Wang Y, Lindorff‐Larsen K, Gad HH, Hartmann R, Lyons JA, Fenton RA, Nissen P. Cryo-EM structure of the human NKCC1 transporter reveals mechanisms of ion coupling and specificity. EMBO J 2022; 41:e110169. [PMID: 36239040 PMCID: PMC9713717 DOI: 10.15252/embj.2021110169] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 09/20/2022] [Accepted: 09/22/2022] [Indexed: 12/03/2022] Open
Abstract
The sodium-potassium-chloride transporter NKCC1 of the SLC12 family performs Na+ -dependent Cl- - and K+ -ion uptake across plasma membranes. NKCC1 is important for regulating cell volume, hearing, blood pressure, and regulation of hyperpolarizing GABAergic and glycinergic signaling in the central nervous system. Here, we present a 2.6 Å resolution cryo-electron microscopy structure of human NKCC1 in the substrate-loaded (Na+ , K+ , and 2 Cl- ) and occluded, inward-facing state that has also been observed for the SLC6-type transporters MhsT and LeuT. Cl- binding at the Cl1 site together with the nearby K+ ion provides a crucial bridge between the LeuT-fold scaffold and bundle domains. Cl- -ion binding at the Cl2 site seems to undertake a structural role similar to conserved glutamate of SLC6 transporters and may allow for Cl- -sensitive regulation of transport. Supported by functional studies in mammalian cells and computational simulations, we describe a putative Na+ release pathway along transmembrane helix 5 coupled to the Cl2 site. The results provide insight into the structure-function relationship of NKCC1 with broader implications for other SLC12 family members.
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Affiliation(s)
- Caroline Neumann
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | | | - Rasmus Kock Flygaard
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Michael Habeck
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | | | - Yong Wang
- Linderstrøm‐Lang Centre for Protein Science, Department of BiologyUniversity of CopenhagenCopenhagenDenmark,Shanghai Institute for Advanced Study, Institute of Quantitative Biology, College of Life SciencesZhejiang UniversityHangzhouChina
| | - Kresten Lindorff‐Larsen
- Linderstrøm‐Lang Centre for Protein Science, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Hans Henrik Gad
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Rune Hartmann
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Joseph Anthony Lyons
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark,Interdisciplinary Nanoscience Center (iNANO)Aarhus UniversityAarhusDenmark
| | | | - Poul Nissen
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
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15
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Rosenbaek LL, Petrillo F, van Bemmelen MX, Staub O, Murali SK, Fenton RA. The E3 ubiquitin-protein ligase Nedd4-2 regulates the sodium chloride cotransporter NCC but is not required for a potassium-induced reduction of NCC expression. Front Physiol 2022; 13:971251. [PMID: 36160843 PMCID: PMC9490057 DOI: 10.3389/fphys.2022.971251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022] Open
Abstract
Na+ and K+ balance is influenced by the activity of the sodium chloride cotransporter NCC in the distal convoluted tubule. NCC activity and abundance are reduced by high extracellular K+. The E3 ubiquitin ligase neural precursor cell expressed developmentally downregulated 4–2 (Nedd4-2) has been proposed as a modulator of NCC abundance. Here, we examined the functional role of Nedd4-2 on NCC regulation and whether Nedd4-2 is important for the effects of high extracellular K+ on NCC. Total and plasma membrane levels of ubiquitylated NCC were lower in NCC-expressing MDCKI cells after Nedd4-2 deletion. NCC and phosphorylated NCC (pT58-NCC) levels were higher after Nedd4-2 deletion, and NCC levels on the plasma membrane were elevated. No significant changes were seen after Nedd4-2 knockdown in the levels of SPAK and phosphorylated SPAK (pS373-SPAK), the major NCC regulatory kinase. Nedd4-2 deficiency had no effect on the internalization rate of NCC from the plasma membrane, but NCC protein half-life was increased. In ex vivo experiments with kidney tubule suspensions from Nedd4-2 knockout (KO) mice, high K+ reduced total and pT58-NCC regardless of genotype. We conclude that Nedd4-2 is involved in ubiquitylation of NCC and modulating its plasma membrane levels and degradation. However, Nedd4-2 does not appear to be important for K+ induced reductions in NCC abundance.
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Affiliation(s)
- Lena L. Rosenbaek
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
| | | | - Miguel X. van Bemmelen
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Olivier Staub
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Sathish K. Murali
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Robert A. Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- *Correspondence: Robert A. Fenton,
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16
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Wu A, Wolley MJ, Matthews A, Cowley D, Welling PA, Fenton RA, Stowasser M. In Primary Aldosteronism Acute Potassium Chloride Supplementation Suppresses Abundance and Phosphorylation of the Sodium-Chloride Cotransporter. Kidney360 2022; 3:1909-1923. [PMID: 36514401 PMCID: PMC9717638 DOI: 10.34067/kid.0003632022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/25/2022] [Indexed: 01/12/2023]
Abstract
Background Elevated abundance of sodium-chloride cotransporter (NCC) and phosphorylated NCC (pNCC) are potential markers of primary aldosteronism (PA), but these effects may be driven by hypokalemia. Methods We measured plasma potassium in patients with PA. If potassium was <4.0 mmol/L, patients were given sufficient oral potassium chloride (KCl) over 24 hours to achieve as close to 4.0 mmol/L as possible. Clinical chemistries were assessed, and urinary extracellular vesicles (uEVs) were examined to investigate effects on NCC. Results Among 21 patients with PA who received a median total dose of 6.0 g (2.4-16.8 g) of KCl, increases were observed in plasma potassium (from 3.4 to 4.0 mmol/L; P<0.001), aldosterone (from 305 to 558 pmol/L; P=0.01), and renin (from 1.2 to 2.5 mIU/L; P<0.001), whereas decreases were detected in uEV levels of NCC (median fold change(post/basal) [FC]=0.71 [0.09-1.99]; P=0.02), pT60-NCC (FC=0.84 [0.06-1.66]; P=0.05), and pT55/60-NCC (FC=0.67 [0.08-2.42]; P=0.02). By contrast, in 10 patients with PA who did not receive KCl, there were no apparent changes in plasma potassium, NCC abundance, and phosphorylation status, but increases were observed in plasma aldosterone (from 178 to 418 pmol/L; P=0.006) and renin (from 2.0 to 3.0 mU/L; P=0.009). Plasma potassium correlated inversely with uEV levels of NCC (R 2=0.11; P=0.01), pT60-NCC (R 2=0.11; P=0.01), and pT55/60-NCC (R 2=0.11; P=0.01). Conclusions Acute oral KCl loading replenished plasma potassium in patients with PA and suppressed NCC abundance and phosphorylation, despite a significant rise in plasma aldosterone. This supports the view that potassium supplementation in humans with PA overrides the aldosterone stimulatory effect on NCC. The increased plasma aldosterone in patients with PA without KCl supplementation may be due to aldosterone response to posture challenge.
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Affiliation(s)
- Aihua Wu
- Endocrine Hypertension Research Centre, The University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Martin J. Wolley
- Endocrine Hypertension Research Centre, The University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia,Department of Nephrology, Royal Brisbane and Women’s Hospital, Brisbane, Australia
| | - Alexandra Matthews
- Endocrine Hypertension Research Centre, The University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Diane Cowley
- Endocrine Hypertension Research Centre, The University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Paul A. Welling
- Department of Medicine and Physiology, Johns Hopkins University, Baltimore, Maryland
| | | | - Michael Stowasser
- Endocrine Hypertension Research Centre, The University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
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17
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Abstract
Transmembrane potassium (K) gradients are key determinants of membrane potential that can modulate action potentials, control muscle contractility, and influence ion channel and transporter activity. Daily K intake is normally equal to the amount of K in the entire extracellular fluid (ECF) creating a critical challenge - how to maintain ECF [K] and membrane potential in a narrow range during feast and famine. Adaptations to maintain ECF [K] include sensing the K intake, sensing ECF [K] vs. desired set-point and activating mediators that regulate K distribution between ECF and ICF, and regulate renal K excretion. In this focused review, we discuss the basis of these adaptions, including (1) potential mechanisms for rapid feedforward signaling to kidney and muscle after a meal (before a rise in ECF [K]), (2) how skeletal muscles sense and respond to changes in ECF [K], (3) effects of K on aldosterone biosynthesis, and (4) how the kidney responds to changes in ECF [K] to modify K excretion. The concepts of sexual dimorphisms in renal K handling adaptation are introduced, and the molecular mechanisms that can account for the benefits of a K-rich diet to maintain cardiovascular health are discussed. Although the big picture of K homeostasis is becoming more clear, we also highlight significant pieces of the puzzle that remain to be solved, including knowledge gaps in our understanding of initiating signals, sensors and their connection to homeostatic adjustments of ECF [K].
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Affiliation(s)
- Alicia A McDonough
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, USA.
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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18
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Jepsen MR, Østergaard JA, Conover CA, Wogensen L, Birn H, Krag SP, Fenton RA, Oxvig C. Increased activity of the metalloproteinase PAPP-A promotes diabetes-induced glomerular hypertrophy. Metabolism 2022; 132:155218. [PMID: 35588861 DOI: 10.1016/j.metabol.2022.155218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/19/2022] [Accepted: 05/12/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND Diabetic nephropathy (DN) is a serious complication of diabetes and a common cause of end stage renal failure. Insulin-like growth factor (IGF)-signaling has been implicated in DN, but is mechanistically poorly understood. Here, we assessed the activity of the metalloproteinase PAPP-A, an activator of IGF activity, and its possible interaction with the endogenous PAPP-A inhibitors stanniocalcin (STC)-1 and -2 in the mammalian kidney under normal and hyperglycemic conditions. METHODS AND RESULTS Immunohistochemistry demonstrated that PAPP-A, its proteolytic substrate IGF binding protein-4, STC1 and STC2 are present in the human kidney. Endogenous inhibited complexes of PAPP-A (PAPP-A:STC1 and PAPP-A:STC2) were demonstrated in media conditioned by human mesangial cells (HMCs), suggesting that PAPP-A activity is regulated by the STCs in kidney tissue. A method for the selective detection of active PAPP-A in tissue was developed and a significant increase in glomerular active PAPP-A in human diabetic kidney relative to normal was observed. In DN patients, the estimated glomerular filtration rate correlated with PAPP-A activity. In diabetic mice, glomerular growth was reduced when PAPP-A activity was antagonized by adeno-associated virus-mediated overexpression of STC2. CONCLUSION We propose that PAPP-A activity in renal tissue is precisely balanced by STC1 and STC2. An imbalance in this equilibrium causing increased PAPP-A enzymatic activity potentially contributes to the development of DN, and thus, therapeutic targeting of PAPP-A activity may represent a novel strategy for its treatment.
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Affiliation(s)
- Malene R Jepsen
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Jakob A Østergaard
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, DK-8200 Aarhus N, Denmark; Steno Diabetes Center Aarhus, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | | | - Lise Wogensen
- Dean's Office, Faculty of Health, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Henrik Birn
- Department of Renal Medicine, Aarhus University Hospital, DK-8200 Aarhus N, Denmark; Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Søren P Krag
- Department of Histopathology, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
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19
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Xue J, Thomas L, Dominguez Rieg JA, Fenton RA, Rieg T. NHE3 in the thick ascending limb is required for sustained but not acute furosemide-induced urinary acidification. Am J Physiol Renal Physiol 2022; 323:F141-F155. [PMID: 35635321 PMCID: PMC9306792 DOI: 10.1152/ajprenal.00013.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Na+/H+ exchanger isoform 3 (NHE3) facilitates Na+ reabsorption and H+ secretion by the kidneys. Despite stronger NHE3 abundance in the thick ascending limb (TAL) compared to the S1 and S2 segments of the proximal tubule, the role of NHE3 in the TAL is poorly understood. To investigate the role of NHE3 in the TAL, we generated and phenotyped TAL-specific NHE3 knockout mice (NHE3TAL-KO). Compared to control mice, NHE3TAL-KO mice did not show significant differences in body weight, blood pH or plasma Na+, K+ or Cl- levels. Fluid intake trended to be higher and urine osmolality was significantly lower in NHE3TAL-KO mice. Despite a similar GFR, NHE3TAL-KO mice had a greater urinary K+/creatinine ratio. One proposed role of NHE3 relates to furosemide-induced urinary acidification. Acute bolus treatment with furosemide under anesthesia did not result in differences in the dose dependence of urinary flow rate, Cl- excretion or maximal urinary acidification between genotypes; however, in contrast to control mice, urinary pH returned immediately towards baseline levels in NHE3TAL-KO mice. Chronic furosemide treatment reduced urine osmolality similarly in both genotypes but metabolic alkalosis, hypokalemia and calciuresis were absent in NHE3TAL-KO mice. Compared to vehicle, chronic furosemide treatment in control mice resulted in greater NKCC2 and lower Npt2a abundances, effects that were absent in NHE3TAL-KO mice. In summary, NHE3 in the TAL plays a role for the sustained acidification effect of furosemide. Consistent with this, long-term treatment with furosemide did not result in metabolic alkalosis in NHE3TAL-KO mice.
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Affiliation(s)
- Jianxiang Xue
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States.,James A. Haley Veterans' Hospital, Tampa, Florida, United States
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States.,James A. Haley Veterans' Hospital, Tampa, Florida, United States.,Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, United States
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20
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Schepelmann M, Ranieri M, Lopez-Fernandez I, Webberley TS, Brennan SC, Yarova PL, Graca J, Hanif UK, Müller C, Manhardt T, Salzmann M, Quasnichka H, Price SA, Ward DT, Gilbert T, Matchkov VV, Fenton RA, Herberger A, Hwong J, Santa Maria C, Tu CL, Kallay E, Valenti G, Chang W, Riccardi D. Impaired Mineral Ion Metabolism in a Mouse Model of Targeted Calcium-Sensing Receptor (CaSR) Deletion from Vascular Smooth Muscle Cells. J Am Soc Nephrol 2022; 33:1323-1340. [PMID: 35581010 PMCID: PMC9257819 DOI: 10.1681/asn.2021040585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 03/07/2022] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Impaired mineral ion metabolism is a hallmark of CKD-metabolic bone disorder. It can lead to pathologic vascular calcification and is associated with an increased risk of cardiovascular mortality. Loss of calcium-sensing receptor (CaSR) expression in vascular smooth muscle cells exacerbates vascular calcification in vitro. Conversely, vascular calcification can be reduced by calcimimetics, which function as allosteric activators of CaSR. METHODS To determine the role of the CaSR in vascular calcification, we characterized mice with targeted Casr gene knockout in vascular smooth muscle cells ( SM22α CaSR Δflox/Δflox ). RESULTS Vascular smooth muscle cells cultured from the knockout (KO) mice calcified more readily than those from control (wild-type) mice in vitro. However, mice did not show ectopic calcifications in vivo but they did display a profound mineral ion imbalance. Specifically, KO mice exhibited hypercalcemia, hypercalciuria, hyperphosphaturia, and osteopenia, with elevated circulating fibroblast growth factor 23 (FGF23), calcitriol (1,25-D3), and parathyroid hormone levels. Renal tubular α-Klotho protein expression was increased in KO mice but vascular α-Klotho protein expression was not. Altered CaSR expression in the kidney or the parathyroid glands could not account for the observed phenotype of the KO mice. CONCLUSIONS These results suggest that, in addition to CaSR's established role in the parathyroid-kidney-bone axis, expression of CaSR in vascular smooth muscle cells directly contributes to total body mineral ion homeostasis.
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Affiliation(s)
- Martin Schepelmann
- School of Biosciences, Cardiff University, Cardiff, United Kingdom .,Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Marianna Ranieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | | | | | - Sarah C Brennan
- School of Biosciences, Cardiff University, Cardiff, United Kingdom.,Charles Perkins Centre, University of Sydney, Sydney, Australia
| | - Polina L Yarova
- School of Biosciences, Cardiff University, Cardiff, United Kingdom.,Translational and Clinical Research Institute, Newcastle University Medical School, Newcastle upon Tyne, United Kingdom
| | - Joao Graca
- School of Biosciences, Cardiff University, Cardiff, United Kingdom.,AstraZeneca, Macclesfield, United Kingdom
| | | | - Christian Müller
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Teresa Manhardt
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Martina Salzmann
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Helen Quasnichka
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Donald T Ward
- Division of Diabetes, Endocrinology, and Gastroenterology, University of Manchester, Manchester, United Kingdom
| | - Thierry Gilbert
- Centre for Developmental Biology, University Paul Sabatier, Toulouse, France
| | | | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Amanda Herberger
- Department of Medicine, University of California, San Francisco, California
| | - Jenna Hwong
- Department of Medicine, University of California, San Francisco, California
| | | | - Chia-Ling Tu
- Department of Medicine, University of California, San Francisco, California
| | - Enikö Kallay
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Giovanna Valenti
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Wenhan Chang
- Department of Medicine, University of California, San Francisco, California
| | - Daniela Riccardi
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
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21
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Kristensen M, Fenton RA, Poulsen SB. Dissecting the Effects of Aldosterone and Hypokalemia on the Epithelial Na + Channel and the NaCl Cotransporter. Front Physiol 2022; 13:800055. [PMID: 35557966 PMCID: PMC9086401 DOI: 10.3389/fphys.2022.800055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Primary hyperaldosteronism (PA) is characterized by aldosterone excess and hypertension. This may be linked to increased renal Na+ reabsorption via the epithelial Na+ channel (ENaC) and the NaCl cotransporter (NCC). The majority of PA patients have normal plasma K+ levels, but a subset of cases are associated with hypokalemia. High NCC levels observed in long-term studies with aldosterone-infused rodents have been attributed to direct effects of aldosterone. Aldosterone can also increase active phosphorylated NCC (pT58-NCC) acutely. However, direct effects of aldosterone on NCC have been contested by recent studies indicating that it is rather an indirect effect of hypokalemia. We therefore set out to determine isolated long-term aldosterone and K+ effects on ENaC and NCC using various in vivo and ex vivo approaches. In mice, aldosterone-induced hypokalemia was prevented by simultaneous amiloride infusion, coupled to increased cleavage of α- and γENaC but no effect on NCC. Regression analyses of in vivo data showed a positive correlation between aldosterone/K+ and αENaC but a negative correlation with NCC and pT58-NCC. Ex vivo, exposure of kidney tubules for 21 h to aldosterone increased cleavage of αENaC and γENaC, but no effects were observed on NCC or pT58-NCC. Exposure of tubules to low K+ media reduced αENaC but increased NCC and pT58-NCC. As hypokalemia can enhance cell proliferation markers in the distal convoluted tubule (DCT), we hypothesized that aldosterone infusion would increase proliferating cell nuclear antigen (PCNA) expression. Infusion of aldosterone in mice for 6 days greatly increased PCNA expression in the DCT. Collectively, in vivo and ex vivo data suggest that both aldosterone and K+ can increase ENaC directly. In contrast, the observed increase in abundance and phosphorylation of NCC in aldosterone-infused mice is likely an indirect effect of enhanced ENaC-mediated K+ secretion and subsequent hypokalemia. Thus, it is possible that NCC may only be increased in PA when the condition is associated with hypokalemia.
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Affiliation(s)
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Søren B Poulsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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22
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Poulsen SB, Murali SK, Thomas L, Rieg T, Fenton RA. Inhibition of Na
+
/H
+
exchanger‐3 (NHE3) results in hyperphosphatemia without major alterations in Ca
2+
homeostasis. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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Esteva‐Font C, Geurts F, Hoorn EJ, Fenton RA. Genetic Deletion of the Prostaglandin EP4 Receptor in the Kidney Tubule of Adult Male Mice Has Mild Impact on Kidney Water Handling. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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24
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Xue J, Thomas L, Fenton RA, Dominguez Rieg JA, Rieg T. Generation and characterization of thick ascending limb specific knockout of NHE3 mouse model. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r4942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Timo Rieg
- University of South FloridaTampaFL
- James A. Haley VATampaFL
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25
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Thomas L, Xue J, Murali SK, Levy M, Fenton RA, Dominguez Rieg JA, Rieg T. Increased phosphate absorption in mice lacking NHE3 in intestinal epithelial cells. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r4966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | | | - Timo Rieg
- University of South FloridaTampaFL
- James A. Haley VATampaFL
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26
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Wu A, Wolley MJ, Wu Q, Cowley D, Palmfeldt J, Welling PA, Fenton RA, Stowasser M. Acute Intravenous NaCl and Volume Expansion Reduces Sodium-Chloride Cotransporter Abundance and Phosphorylation in Urinary Extracellular Vesicles. Kidney360 2022; 3:910-921. [PMID: 36128481 PMCID: PMC9438418 DOI: 10.34067/kid.0000362022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/28/2022] [Indexed: 01/12/2023]
Abstract
Background Sodium chloride (NaCl) loading and volume expansion suppress the renin-angiotensin-aldosterone system to reduce renal tubular reabsorption of NaCl and water, but effects on the sodium-chloride cotransporter (NCC) and relevant renal transmembrane proteins that are responsible for this modulation in humans are less well investigated. Methods We used urinary extracellular vesicles (uEVs) as an indirect readout to assess renal transmembrane proteins involved in NaCl and water homeostasis in 44 patients with hypertension who had repeatedly raised aldosterone/renin ratios undergoing infusion of 2 L of 0.9% saline over 4 hours. Results When measured by mass spectrometry in 13 patients, significant decreases were observed in NCC (median fold change [FC]=0.70); pendrin (FC=0.84); AQP2 (FC=0.62); and uEV markers, including ALIX (FC=0.65) and TSG101 (FC=0.66). Immunoblotting reproduced the reduction in NCC (FC=0.54), AQP2 (FC=0.42), ALIX (FC=0.52), and TSG101 (FC=0.55) in the remaining 31 patients, and demonstrated a significant decrease in phosphorylated NCC (pNCC; FC=0.49). However, after correction for ALIX, the reductions in NCC (FC=0.90) and pNCC (FC=1.00) were no longer apparent, whereas the significant decrease in AQP2 persisted (FC=0.62). Conclusion We conclude that (1) decreases in NCC and pNCC, induced by acute NaCl loading and volume expansion, may be due to diluted post-test urines; (2) the lack of change of NCC and pNCC when corrected for ALIX, despite a fall in plasma aldosterone, may be due to the lack of change in plasma K+; and (3) the decrease in AQP2 may be due to a decrease in vasopressin in response to volume expansion.
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Affiliation(s)
- Aihua Wu
- Endocrine Hypertension Research Centre, University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Martin J. Wolley
- Endocrine Hypertension Research Centre, University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia,Department of Nephrology, Royal Brisbane and Women’s Hospital, Brisbane, Australia
| | - Qi Wu
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Diane Cowley
- Endocrine Hypertension Research Centre, University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Johan Palmfeldt
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Paul A. Welling
- Department of Medicine and Physiology, Johns Hopkins University, Baltimore, Maryland
| | | | - Michael Stowasser
- Endocrine Hypertension Research Centre, University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
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27
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Xue J, Thomas L, Murali SK, Levi M, Fenton RA, Dominguez Rieg JA, Rieg T. Enhanced phosphate absorption in intestinal epithelial cell-specific NHE3 knockout mice. Acta Physiol (Oxf) 2022; 234:e13756. [PMID: 34978760 PMCID: PMC9286053 DOI: 10.1111/apha.13756] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/16/2021] [Accepted: 01/01/2022] [Indexed: 12/11/2022]
Abstract
Aims The kidneys play a major role in maintaining Pi homeostasis. Patients in later stages of CKD develop hyperphosphatemia. One novel treatment option is tenapanor, an intestinal‐specific NHE3 inhibitor. To gain mechanistic insight into the role of intestinal NHE3 in Pi homeostasis, we studied tamoxifen‐inducible intestinal epithelial cell‐specific NHE3 knockout (NHE3IEC‐KO) mice. Methods Mice underwent dietary Pi challenges, and hormones as well as urinary/plasma Pi were determined. Intestinal 33P uptake studies were conducted in vivo to compare the effects of tenapanor and NHE3IEC‐KO. Ex vivo Pi transport was measured in everted gut sacs and brush border membrane vesicles. Intestinal and renal protein expression of Pi transporters were determined. Results On the control diet, NHE3IEC‐KO mice had similar Pi homeostasis, but a ~25% reduction in FGF23 compared with control mice. Everted gut sacs and brush border membrane vesicles showed enhanced Pi uptake associated with increased Npt2b expression in NHE3IEC‐KO mice. Acute oral Pi loading resulted in higher plasma Pi in NHE3IEC‐KO mice. Tenapanor inhibited intestinal 33P uptake acutely but then led to hyper‐absorption at later time points compared to vehicle. In response to high dietary Pi, plasma Pi and FGF23 increased to higher levels in NHE3IEC‐KO mice which was associated with greater Npt2b expression. Reduced renal Npt2c and a trend for reduced Npt2a expression were unable to correct for higher plasma Pi. Conclusion Intestinal NHE3 has a significant contribution to Pi homeostasis. In contrast to effects described for tenapanor on Pi homeostasis, NHE3IEC‐KO mice show enhanced, rather than reduced, intestinal Pi uptake.
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Affiliation(s)
- Jianxiang Xue
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
| | | | - Moshe Levi
- Department of Biochemistry and Molecular & Cellular Biology Georgetown University Washington District of Columbia USA
| | | | - Jessica A. Dominguez Rieg
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
- James A. Haley Veterans' Hospital Tampa Florida USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
- James A. Haley Veterans' Hospital Tampa Florida USA
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28
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Deen PMT, Boone M, Schweer H, Olesen ETB, Carmone C, Wetzels JFM, Fenton RA, Kortenoeven MLA. A Vasopressin-Induced Change in Prostaglandin Receptor Subtype Expression Explains the Differential Effect of PGE2 on AQP2 Expression. Front Physiol 2022; 12:787598. [PMID: 35126177 PMCID: PMC8814457 DOI: 10.3389/fphys.2021.787598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/07/2021] [Indexed: 11/20/2022] Open
Abstract
Arginine vasopressin (AVP) stimulates the concentration of renal urine by increasing the principal cell expression of aquaporin-2 (AQP2) water channels. Prostaglandin E2 (PGE2) and prostaglandin2α (PGF2α) increase the water absorption of the principal cell without AVP, but PGE2 decreases it in the presence of AVP. The underlying mechanism of this paradoxical response was investigated here. Mouse cortical collecting duct (mkpCCDc14) cells mimic principal cells as they endogenously express AQP2 in response to AVP. PGE2 increased AQP2 abundance without desmopressin (dDAVP), while in the presence of dDAVP, PGE2, and PGF2α reduced AQP2 abundance. dDAVP increased the cellular PGD2 and PGE2 release and decreased the PGF2α release. MpkCCD cells expressed mRNAs for the receptors of PGE2 (EP1/EP4), PGF2 (FP), and TxB2 (TP). Incubation with dDAVP increased the expression of EP1 and FP but decreased the expression of EP4. In the absence of dDAVP, incubation of mpkCCD cells with an EP4, but not EP1/3, agonist increased AQP2 abundance, and the PGE2-induced increase in AQP2 was blocked with an EP4 antagonist. Moreover, in the presence of dDAVP, an EP1/3, but not EP4, agonist decreased the AQP2 abundance, and the addition of EP1 antagonists prevented the PGE2-mediated downregulation of AQP2. Our study shows that in mpkCCDc14 cells, reduced EP4 receptor and increased EP1/FP receptor expression by dDAVP explains the differential effects of PGE2 and PGF2α on AQP2 abundance with or without dDAVP. As the V2R and EP4 receptor, but not the EP1 and FP receptor, can couple to Gs and stimulate the cyclic adenosine monophosphate (cAMP) pathway, our data support a view that cells can desensitize themselves for receptors activating the same pathway and sensitize themselves for receptors of alternative pathways.
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Affiliation(s)
- Peter M. T. Deen
- Department of Physiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Michelle Boone
- Department of Physiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Horst Schweer
- Department of Pediatrics, Philipps-University Marburg, Marburg, Germany
| | - Emma T. B. Olesen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Endocrinology and Nephrology, North Zealand Hospital, Hillerød, Denmark
| | - Claudia Carmone
- Department of Physiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Jack F. M. Wetzels
- Department of Nephrology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | | | - Marleen L. A. Kortenoeven
- Department of Physiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
- *Correspondence: Marleen L. A. Kortenoeven
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Wu A, Wolley MJ, Fenton RA, Stowasser M. Using human urinary extracellular vesicles to study physiological and pathophysiological states and regulation of the sodium chloride cotransporter. Front Endocrinol (Lausanne) 2022; 13:981317. [PMID: 36105401 PMCID: PMC9465297 DOI: 10.3389/fendo.2022.981317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/09/2022] [Indexed: 11/29/2022] Open
Abstract
The thiazide-sensitive sodium chloride cotransporter (NCC), expressed in the renal distal convoluted tubule, plays a major role in Na+, Cl- and K+ homeostasis and blood pressure as exemplified by the symptoms of patients with non-functional NCC and Gitelman syndrome. NCC activity is modulated by a variety of hormones, but is also influenced by the extracellular K+ concentration. The putative "renal-K+ switch" mechanism is a relatively cohesive model that links dietary K+ intake to NCC activity, and may offer new targets for blood pressure control. However, a remaining hurdle for full acceptance of this model is the lack of human data to confirm molecular findings from animal models. Extracellular vesicles (EVs) have attracted attention from the scientific community due to their potential roles in intercellular communication, disease pathogenesis, drug delivery and as possible reservoirs of biomarkers. Urinary EVs (uEVs) are an excellent sample source for the study of physiology and pathology of renal, urothelial and prostate tissues, but the diverse origins of uEVs and their dynamic molecular composition present both methodological and data interpretation challenges. This review provides a brief overview of the state-of-the-art, challenges and knowledge gaps in current uEV-based analyses, with a focus on the application of uEVs to study the "renal-K+ switch" and NCC regulation. We also provide recommendations regarding biospecimen handling, processing and reporting requirements to improve experimental reproducibility and interoperability towards the realisation of the potential of uEV-derived biomarkers in hypertension and clinical practice.
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Affiliation(s)
- Aihua Wu
- Endocrine Hypertension Research Centre, University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, QLD, Australia
| | - Martin J. Wolley
- Endocrine Hypertension Research Centre, University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, QLD, Australia
- Department of Nephrology, Royal Brisbane and Women’s Hospital, Brisbane, QLD, Australia
| | | | - Michael Stowasser
- Endocrine Hypertension Research Centre, University of Queensland Diamantina Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, QLD, Australia
- *Correspondence: Michael Stowasser,
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Yde J, Wu Q, Borg JF, Fenton RA, Moeller HB. A systems-level analysis of bile acids effects on rat colon epithelial cells. Am J Physiol Gastrointest Liver Physiol 2022; 322:G34-G48. [PMID: 34643455 DOI: 10.1152/ajpgi.00178.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 10/08/2021] [Indexed: 01/31/2023]
Abstract
Bile acid diarrhea is a chronic condition caused by increased delivery of bile acids to the colon. The underlying mechanisms remain to be elucidated. To investigate genes involved in bile acid diarrhea, systems-level analyses were used on a rat bile acid diarrhea model. Twelve male Wistar Munich rats, housed in metabolic cages, were fed either control or bile acid-mixed (1% wt/wt) diets for 10 days. Food intake, water intake, urine volume, body weight, and fecal output were monitored daily. After euthanasia, colonic epithelial cells were isolated using calcium chelation and processed for systems-level analyses, that is, RNA-sequencing transcriptomics and mass spectrometry proteomics. Bile acid-fed rats suffered diarrhea, indicated by increased drinking, feces weight, and fecal water content compared with control rats. Urine output was unchanged. With bile acid feeding, RNA-sequencing revealed 204 increased and 401 decreased mRNAs; mass spectrometry revealed 183 increased and 111 decreased proteins. Among the altered genes were genes associated with electrolyte and water transport (including Slc12a7, Clca4, and Aqp3) and genes associated with bile acid transport (Slc2b1, Abcg2, Slc51a, Slc51b, and Fabps). Correlation analysis showed a significant positive correlation (Pearson's r = 0.28) between changes in mRNA expression and changes in protein expression. However, caution must be exercised in making a direct correlation between experimentally determined transcriptomes and proteomes. Genes associated with bile acid transport responded to bile acid feeding, suggesting that colonic bile acid transport also occur by regulated protein facilitated mechanisms in addition to passive diffusion. In summary, the study provides annotated rat colonic epithelial cell transcriptome and proteome with response to bile acid feeding.NEW & NOTEWORTHY Feeding rats with a bile acid caused changes in fecal output, underlining this bile acid diarrhea model's usefulness. Colonic epithelial expression of genes associated with facilitated transport of bile acids was altered during bile acid feeding. The study raises the possibility of regulated colonic transepithelial transport of bile acids in response to luminal bile acids. In addition, this study provides annotated rat colonic epithelial cell transcriptome and proteome with response to bile acid feeding.
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Affiliation(s)
- Jonathan Yde
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Qi Wu
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Johan F Borg
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Hanne B Moeller
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Aroankins TS, Murali SK, Fenton RA, Wu Q. The Hydrogen-Coupled Oligopeptide Membrane Cotransporter Pept2 is SUMOylated in Kidney Distal Convoluted Tubule Cells. Front Mol Biosci 2021; 8:790606. [PMID: 34881291 PMCID: PMC8646034 DOI: 10.3389/fmolb.2021.790606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Protein post-translational modification by the Small Ubiquitin-like MOdifier (SUMO) on lysine residues is a reversible process highly important for transcription and protein stability. In the kidney, SUMOylation appears to be important for the cellular response to aldosterone. Therefore, in this study, we generated a SUMOylation profile of the aldosterone-sensitive kidney distal convoluted tubule (DCT) as a basis for understanding SUMOylation events in this cell type. Using mass spectrometry-based proteomics, 1037 SUMO1 and 552 SUMO2 sites, corresponding to 546 SUMO1 and 356 SUMO2 proteins, were identified from a modified mouse kidney DCT cell line (mpkDCT). SUMOylation of the renal hydrogen-coupled oligopeptide and drug co-transporter (Pept2) at one site (K139) was found to be highly regulated by aldosterone. Using immunolabelling of mouse kidney sections Pept2 was localized to DCT cells in vivo. Aldosterone stimulation of mpkDCT cell lines expressing wild-type Pept2 or mutant K139R-Pept2, post-transcriptionally increased Pept2 expression up to four-fold. Aldosterone decreased wild-type Pept2 abundance in the apical membrane domain of mpkDCT cells, but this response was absent in K139R-Pept2 expressing cells. In summary, we have generated a SUMOylation landscape of the mouse DCT and determined that SUMOylation plays an important role in the physiological regulation of Pept2 trafficking by aldosterone.
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Affiliation(s)
- Takwa S Aroankins
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Department of Anesthesiology and Intensive Care, Sahlgrenska University Hospital, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | | | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Qi Wu
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Reusch B, Bartram MP, Dafinger C, Palacio-Escat N, Wenzel A, Fenton RA, Saez-Rodriguez J, Schermer B, Benzing T, Altmüller J, Beck BB, Rinschen MM. MAGED2 controls vasopressin-induced aquaporin-2 expression in collecting duct cells. J Proteomics 2021; 252:104424. [PMID: 34775100 DOI: 10.1016/j.jprot.2021.104424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/19/2021] [Accepted: 11/01/2021] [Indexed: 11/30/2022]
Abstract
Mutations in the Melanoma-Associated Antigen D2 (MAGED2) cause antenatal Bartter syndrome type 5 (BARTS5). This rare disease is characterized by perinatal loss of urinary concentration capability and large urine volumes. The underlying molecular mechanisms of this disease are largely unclear. Here, we study the effect of MAGED2 knockdown on kidney cell cultures using proteomic and phosphoproteomic analyses. In HEK293T cells, MAGED2 knockdown induces prominent changes in protein phosphorylation rather than changes in protein abundance. MAGED2 is expressed in mouse embryonic kidneys and its expression declines during development. MAGED2 interacts with G-protein alpha subunit (GNAS), suggesting a role in G-protein coupled receptors (GPCR) signalling. In kidney collecting duct cell lines, Maged2 knockdown subtly modulated vasopressin type 2 receptor (V2R)-induced cAMP-generation kinetics, rewired phosphorylation-dependent signalling, and phosphorylation of CREB. Maged2 knockdown resulted in a large increase in aquaporin-2 abundance during long-term V2R activation. The increase in aquaporin-2 protein was mediated transcriptionally. Taken together, we link MAGED2 function to cellular signalling as a desensitizer of V2R-induced aquaporin-2 expression. SIGNIFICANCE: In most forms of Bartter Syndrome, the underlying cause of the disease is well understood. In contrast, the role of MAGED2 mutations in a newly discovered form of Bartter Syndrome (BARTS5) is unknown. In our manuscript we could show that MAGED2 modulates vasopressin-induced protein and phosphorylation patterns in kidney cells, providing a broad basis for further studies of MAGED2 function in development and disease.
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Affiliation(s)
- Björn Reusch
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Malte P Bartram
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Department II of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany
| | - Claudia Dafinger
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Department II of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; CECAD, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Nicolàs Palacio-Escat
- Joint Research Centre for Computational Biomedicine (JRC-COMBINE), Faculty of Medicine, RWTH Aachen University, 52074 Aachen, Germany; Institute of Computational Biomedicine, Bioquant, Faculty of Medicine, Heidelberg University, 69120 Heidelberg, Germany
| | - Andrea Wenzel
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Julio Saez-Rodriguez
- Joint Research Centre for Computational Biomedicine (JRC-COMBINE), Faculty of Medicine, RWTH Aachen University, 52074 Aachen, Germany; Institute of Computational Biomedicine, Bioquant, Faculty of Medicine, Heidelberg University, 69120 Heidelberg, Germany; European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge CB10 1SD, United Kingdom
| | - Bernhard Schermer
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Department II of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; CECAD, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Thomas Benzing
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Department II of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; CECAD, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Janine Altmüller
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Cologne Center for Genomics, University of Cologne, 50931 Cologne, Germany; Berlin Institute of Health at Charité, Core Facility Genomics, 10178 Berlin, Germany; Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 10115 Berlin, Germany
| | - Bodo B Beck
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany.
| | - Markus M Rinschen
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Department II of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark; III Department of Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; Aarhus Institute of Advanced Studies (AIAS), Aarhus University, 8000 Aarhus, Denmark.
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Abstract
Targeting the collecting duct water channel aquaporin 2 (AQP2) to the plasma membrane is essential for the maintenance of mammalian water homeostasis. The vasopressin V2 receptor (V2R), which is a GS protein-coupled receptor that increases intracellular cAMP levels, has a major role in this targeting process. Although a rise in cAMP levels and activation of protein kinase A are involved in facilitating the actions of V2R, studies in knockout mice and cell models have suggested that cAMP signalling pathways are not an absolute requirement for V2R-mediated AQP2 trafficking to the plasma membrane. In addition, although AQP2 phosphorylation is a known prerequisite for V2R-mediated plasma membrane targeting, none of the known AQP2 phosphorylation events appears to be rate-limiting in this process, which suggests the involvement of other factors; cytoskeletal remodelling has also been implicated. Notably, several regulatory processes and signalling pathways involved in AQP2 trafficking also have a role in the pathophysiology of autosomal dominant polycystic kidney disease, although the role of AQP2 in cyst progression is unknown. Here, we highlight advances in the field of AQP2 regulation that might be exploited for the treatment of water balance disorders and provide a rationale for targeting these pathways in autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Endocrinology and Nephrology, North Zealand Hospital, Hillerød, Denmark.
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus, Denmark.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Wu Q, Poulsen SB, Murali SK, Grimm PR, Su XT, Delpire E, Welling PA, Ellison DH, Fenton RA. Large-Scale Proteomic Assessment of Urinary Extracellular Vesicles Highlights Their Reliability in Reflecting Protein Changes in the Kidney. J Am Soc Nephrol 2021; 32:2195-2209. [PMID: 34230103 PMCID: PMC8729841 DOI: 10.1681/asn.2020071035] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 04/12/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Urinary extracellular vesicles (uEVs) are secreted into urine by cells from the kidneys and urinary tract. Although changes in uEV proteins are used for quantitative assessment of protein levels in the kidney or biomarker discovery, whether they faithfully reflect (patho)physiologic changes in the kidney is a matter of debate. METHODS Mass spectrometry was used to compare in an unbiased manner the correlations between protein levels in uEVs and kidney tissue from the same animal. Studies were performed on rats fed a normal or high K+ diet. RESULTS Absolute quantification determined a positive correlation (Pearson R=0.46 or 0.45, control or high K+ respectively, P<0.0001) between the approximately 1000 proteins identified in uEVs and corresponding kidney tissue. Transmembrane proteins had greater positive correlations relative to cytoplasmic proteins. Proteins with high correlations (R>0.9), included exosome markers Tsg101 and Alix. Relative quantification highlighted a monotonic relationship between altered transporter/channel abundances in uEVs and the kidney after dietary K+ manipulation. Analysis of genetic mouse models also revealed correlations between uEVs and kidney. CONCLUSION This large-scale unbiased analysis identifies uEV proteins that track the abundance of the parent proteins in the kidney. The data form a novel resource for the kidney community and support the reliability of using uEV protein changes to monitor specific physiologic responses and disease mechanisms.
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Affiliation(s)
- Qi Wu
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | | | - Paul R. Grimm
- Departments of Medicine and Physiology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Xiao-Tong Su
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Paul A. Welling
- Departments of Medicine and Physiology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - David H. Ellison
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
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Abstract
Introduction: Kidney dysfunction poses a high burden on patients and health care systems. Early detection and accurate prediction of kidney disease progression remains a major challenge. Compared to existing clinical parameters, urinary proteomics has the potential to reveal molecular alterations within the kidney that may alter its function before the onset of clinical symptoms. Thus, urinary proteomics has greater prognostic potential for assessment of kidney dysfunction progression.Areas covered: Advances in urinary proteomics for major causes of kidney dysfunction are discussed. The application of urinary extracellular vesicles for studying kidney dysfunction are discussed. Technological advances in urinary proteomics are discussed. The literature was identified using a database search for titles containing 'proteom*' and 'urin*' and published within the past 5 years. Retrieved literature was manually filtered to retain kidney dysfunctions-related studies.Expert opinion: Despite major advances, diagnosis by urinary proteomics has not been fully applied in any clinical settings. This could be attributed to the complex nature of kidney diseases, in addition to the constraints on study power and feasibility of incorporating mass spectrometry techniques in daily routine analysis. Nevertheless, we are confident that advances in urinary proteomics will soon provide superior insights into kidney disease beyond existing clinical parameters.
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Affiliation(s)
- Qi Wu
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Kortenoeven MLA, Esteva-Font C, Dimke H, Poulsen SB, Murali SK, Fenton RA. High dietary potassium causes ubiquitin-dependent degradation of the kidney sodium-chloride cotransporter. J Biol Chem 2021; 297:100915. [PMID: 34174287 PMCID: PMC8318901 DOI: 10.1016/j.jbc.2021.100915] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 11/24/2022] Open
Abstract
The thiazide-sensitive sodium-chloride cotransporter (NCC) in the renal distal convoluted tubule (DCT) plays a critical role in regulating blood pressure (BP) and K+ homeostasis. During hyperkalemia, reduced NCC phosphorylation and total NCC abundance facilitate downstream electrogenic K+ secretion and BP reduction. However, the mechanism for the K+-dependent reduction in total NCC levels is unknown. Here, we show that NCC levels were reduced in ex vivo renal tubules incubated in a high-K+ medium for 24–48 h. This reduction was independent of NCC transcription, but was prevented using inhibitors of the proteasome (MG132) or lysosome (chloroquine). Ex vivo, high K+ increased NCC ubiquitylation, but inhibition of the ubiquitin conjugation pathway prevented the high K+-mediated reduction in NCC protein. In tubules incubated in high K+ media ex vivo or in the renal cortex of mice fed a high K+ diet for 4 days, the abundance and phosphorylation of heat shock protein 70 (Hsp70), a key regulator of ubiquitin-dependent protein degradation and protein folding, were decreased. Conversely, in similar samples the expression of PP1α, known to dephosphorylate Hsp70, was also increased. NCC coimmunoprecipitated with Hsp70 and PP1α, and inhibiting their actions prevented the high K+-mediated reduction in total NCC levels. In conclusion, we show that hyperkalemia drives NCC ubiquitylation and degradation via a PP1α-dependent process facilitated by Hsp70. This mechanism facilitates K+-dependent reductions in NCC to protect plasma K+ homeostasis and potentially reduces BP.
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Affiliation(s)
- Marleen L A Kortenoeven
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark; Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.
| | - Cristina Esteva-Font
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, 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
| | - Søren B Poulsen
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Sathish K Murali
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark.
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Petrillo F, Iervolino A, Angrisano T, Jelen S, Costanzo V, D’Acierno M, Cheng L, Wu Q, Guerriero I, Mazzarella MC, De Falco A, D’Angelo F, Ceccarelli M, Caraglia M, Capasso G, Fenton RA, Trepiccione F. Dysregulation of Principal Cell miRNAs Facilitates Epigenetic Regulation of AQP2 and Results in Nephrogenic Diabetes Insipidus. J Am Soc Nephrol 2021; 32:1339-1354. [PMID: 33727367 PMCID: PMC8259636 DOI: 10.1681/asn.2020010031] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/02/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND MicroRNAs (miRNAs), formed by cleavage of pre-microRNA by the endoribonuclease Dicer, are critical modulators of cell function by post-transcriptionally regulating gene expression. METHODS Selective ablation of Dicer in AQP2-expressing cells (DicerAQP2Cre+ mice) was used to investigate the role of miRNAs in the kidney collecting duct of mice. RESULTS The mice had severe polyuria and nephrogenic diabetes insipidus, potentially due to greatly reduced AQP2 and AQP4 levels. Although epithelial sodium channel levels were decreased in cortex and increased in inner medulla, amiloride-sensitive sodium reabsorption was equivalent in DicerAQP2Cre+ mice and controls. Small-RNA sequencing and proteomic analysis revealed 31 and 178 significantly regulated miRNAs and proteins, respectively. Integrated bioinformatic analysis of the miRNAome and proteome suggested alterations in the epigenetic machinery and various transcription factors regulating AQP2 expression in DicerAQP2Cre+ mice. The expression profile and function of three miRNAs (miR-7688-5p, miR-8114, and miR-409-3p) whose predicted targets were involved in epigenetic control (Phf2, Kdm5c, and Kdm4a) or transcriptional regulation (GATA3, GATA2, and ELF3) of AQP2 were validated. Luciferase assays could not demonstrate direct interaction of AQP2 or the three potential transcription factors with miR-7688-5p, miR-8114, and miR-409-3p. However, transfection of respective miRNA mimics reduced AQP2 expression. Chromatin immunoprecipitation assays demonstrated decreased Phf2 and significantly increased Kdm5c interactions at the Aqp2 gene promoter in DicerAQP2Cre+ mice, resulting in decreased RNA Pol II association. CONCLUSIONS Novel evidence indicates miRNA-mediated epigenetic regulation of AQP2 expression.
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Affiliation(s)
- Federica Petrillo
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Anna Iervolino
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy
| | - Tiziana Angrisano
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Sabina Jelen
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy
| | - Vincenzo Costanzo
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy
| | | | - Lei Cheng
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Qi Wu
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ilaria Guerriero
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy
| | | | - Alfonso De Falco
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy
| | - Fulvio D’Angelo
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy
| | - Michele Ceccarelli
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy,Department of Electrical Engineering and Information Technology (DIETI) University of Naples “Federico II”, Naples, Italy
| | - Michele Caraglia
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Giovambattista Capasso
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy,Department of Translational Medical Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | | | - Francesco Trepiccione
- Biogem, Institute of Genetic Research “Gaetano Salvatore”, Ariano Irpino, Italy,Department of Translational Medical Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
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Blijdorp CJ, Tutakhel OAZ, Hartjes TA, van den Bosch TPP, van Heugten MH, Rigalli JP, Willemsen R, Musterd-Bhaggoe UM, Barros ER, Carles-Fontana R, Carvajal CA, Arntz OJ, van de Loo FAJ, Jenster G, Clahsen-van Groningen MC, Cuevas CA, Severs D, Fenton RA, van Royen ME, Hoenderop JGJ, Bindels RJM, Hoorn EJ. Comparing Approaches to Normalize, Quantify, and Characterize Urinary Extracellular Vesicles. J Am Soc Nephrol 2021; 32:1210-1226. [PMID: 33782168 PMCID: PMC8259679 DOI: 10.1681/asn.2020081142] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/15/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Urinary extracellular vesicles (uEVs) are a promising source for biomarker discovery, but optimal approaches for normalization, quantification, and characterization in spot urines are unclear. METHODS Urine samples were analyzed in a water-loading study, from healthy subjects and patients with kidney disease. Urine particles were quantified in whole urine using nanoparticle tracking analysis (NTA), time-resolved fluorescence immunoassay (TR-FIA), and EVQuant, a novel method quantifying particles via gel immobilization. RESULTS Urine particle and creatinine concentrations were highly correlated in the water-loading study (R2 0.96) and in random spot urines from healthy subjects (R2 0.47-0.95) and patients (R2 0.41-0.81). Water loading reduced aquaporin-2 but increased Tamm-Horsfall protein (THP) and particle detection by NTA. This finding was attributed to hypotonicity increasing uEV size (more EVs reach the NTA size detection limit) and reducing THP polymerization. Adding THP to urine also significantly increased particle count by NTA. In both fluorescence NTA and EVQuant, adding 0.01% SDS maintained uEV integrity and increased aquaporin-2 detection. Comparison of intracellular- and extracellular-epitope antibodies suggested the presence of reverse topology uEVs. The exosome markers CD9 and CD63 colocalized and immunoprecipitated selectively with distal nephron markers. Conclusions uEV concentration is highly correlated with urine creatinine, potentially replacing the need for uEV quantification to normalize spot urines. Additional findings relevant for future uEV studies in whole urine include the interference of THP with NTA, excretion of larger uEVs in dilute urine, the ability to use detergent to increase intracellular-epitope recognition in uEVs, and CD9 or CD63 capture of nephron segment-specific EVs.
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Affiliation(s)
- Charles J. Blijdorp
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Omar A. Z. Tutakhel
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands,Department of Translational Metabolic Laboratory, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thomas A. Hartjes
- Department of Pathology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Thierry P. P. van den Bosch
- Department of Pathology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Martijn H. van Heugten
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Juan Pablo Rigalli
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Usha M. Musterd-Bhaggoe
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Eric R. Barros
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands,Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Roger Carles-Fontana
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands,Institute of Hepatology, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Cristian A. Carvajal
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Onno J. Arntz
- Department of Experimental Rheumatology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Fons A. J. van de Loo
- Department of Experimental Rheumatology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Guido Jenster
- Department of Urology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | | | - Cathy A. Cuevas
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - David Severs
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Robert A. Fenton
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Martin E. van Royen
- Department of Pathology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Joost G. J. Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J. M. Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
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Poulsen SB, Cheng L, Penton D, Kortenoeven MLA, Matchkov VV, Loffing J, Little R, Murali SK, Fenton RA. Activation of the kidney sodium chloride cotransporter by the β2-adrenergic receptor agonist salbutamol increases blood pressure. Kidney Int 2021; 100:321-335. [PMID: 33940111 DOI: 10.1016/j.kint.2021.04.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/26/2021] [Accepted: 04/01/2021] [Indexed: 12/30/2022]
Abstract
The thiazide-sensitive sodium-chloride-cotransporter (NCC) in the kidney distal convoluted tubule (DCT) plays an essential role in sodium and potassium homeostasis. Here, we demonstrate that NCC activity is increased by the β2-adrenoceptor agonist salbutamol, a drug prevalently used to treat asthma. Relative to β1-adrenergic receptors, the β2-adrenergic receptors were greatly enriched in mouse DCT cells. In mice, administration of salbutamol increased NCC phosphorylation (indicating increased activity) within 30 minutes but also caused hypokalemia, which also increases NCC phosphorylation. In ex vivo kidney slices and isolated tubules, salbutamol increased NCC phosphorylation in the pharmacologically relevant range of 0.01-10 μM, an effect observed after 15 minutes and maintained at 60 minutes. Inhibition of the inwardly rectifying potassium channel (Kir) 4.1 or the downstream with-no-lysine kinases (WNKs) and STE20/SPS1-related proline alanine-rich kinase (SPAK) pathway greatly attenuated, but did not prevent, salbutamol-induced NCC phosphorylation. Salbutamol increased cAMP in tubules, kidney slices and mpkDCT cells (model of DCT). Phosphoproteomics indicated that protein phosphatase 1 (PP1) was a key upstream regulator of salbutamol effects. A role for PP1 and the PP1 inhibitor 1 (I1) was confirmed in tubules using inhibitors of PP1 or kidney slices from I1 knockout mice. On normal and high salt diets, salbutamol infusion increased systolic blood pressure, but this increase was normalized by thiazide suggesting a role for NCC. Thus, β2-adrenergic receptor signaling modulates NCC activity via I1/PP1 and WNK-dependent pathways, and chronic salbutamol administration may be a risk factor for hypertension.
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Affiliation(s)
- Søren B Poulsen
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Lei Cheng
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - David Penton
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | | | | | | | - Robert Little
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Sathish K Murali
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark.
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41
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Kortenoeven MLA, Cheng L, Wu Q, Fenton RA. An in vivo protein landscape of the mouse DCT during high dietary K + or low dietary Na + intake. Am J Physiol Renal Physiol 2021; 320:F908-F921. [PMID: 33779313 DOI: 10.1152/ajprenal.00064.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The hormone aldosterone is essential for maintaining K+ and Na+ balance and controlling blood pressure. Aldosterone has different effects if it is secreted due to hypovolemia or hyperkalemia. The kidney distal convoluted tubule (DCT) is believed to play a central role in mediating the differential responses to aldosterone. To determine the alterations in the DCT that may be responsible for these effects, male mice with green fluorescent protein expression specifically in the DCT were maintained on diets containing low NaCl (hypovolemic state) or high potassium citrate (hyperkalemic state) for 4 days, and DCT cells were isolated using fluorescence-activated cell sorting. This pure population of DCT cells was subjected to analysis by liquid chromatography-coupled tandem mass spectrometry. Over 3,000 proteins were identified in the DCT, creating the first proteome of the mouse DCT. Of the identified proteins, 210 proteins were altered in abundance following a low-NaCl diet and 625 proteins following the high-K+ diet. Many of these changes were not detectable by analyzing whole kidney samples from the same animals. When comparing responses to high-K+ versus low-Na+ diets, protein translation, chaperone-mediated protein folding, and protein ubiquitylation were likely to be significantly altered in the DCT subsequent to a high-K+ diet. In conclusion, this study defines an in vivo protein landscape of the DCT in male mice following either a low-NaCl or a high-K+ diet and acts as an essential resource for the kidney research community.NEW & NOTEWORTHY The mineralocorticoid aldosterone, essential for maintaining body K+ and Na+ balance, has different effects if secreted due to hypovolemia or hyperkalemia. Here, we used proteomics to profile kidney distal convoluted tubule (DCT) cells isolated by a novel FACS approach from mice fed a low-Na+ diet (mimicking hypovolemia) or a high-K+ diet (mimicking hyperkalemia). The study provides the first in-depth proteome of the mouse DCT and insights into how it is physiologically regulated.
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Affiliation(s)
- Marleen L A Kortenoeven
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark.,Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Lei Cheng
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Qi Wu
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
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Abraham S, Paknikar R, Bhumbra S, Luan D, Venkatareddy M, O'Connor C, Bitzer M, Fenton RA, Hurd T, Garg P, Patel SR. Epigenetic regulation of arginine vasopressin receptor 2 expression by PAX2 and Pax transcription interacting protein. Am J Physiol Renal Physiol 2021; 320:F404-F417. [PMID: 33522413 PMCID: PMC7988803 DOI: 10.1152/ajprenal.00371.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 11/22/2022] Open
Abstract
Renal arginine vasopressin receptor 2 (AVPR2) plays a crucial role in osmoregulation. Engagement of ligand with AVPR2 results in aquaporin 2 movement to the apical membrane and water reabsorption from the urinary filtrate. Despite this essential role, little is known about transcriptional regulation of Avpr2. Here, we identify novel roles for PAX2, a transcription factor crucial for kidney development, and its adaptor protein, Pax transcription interacting protein (PTIP), for epigenetic regulation of Avpr2 and thus body water balance. Chromatin immunoprecipitation (ChIP) from murine inner medulla cells (IMCD-3) identified the minimal DNA-binding region of PAX2 on the Avpr2 promoter. Regulation of Avpr2 by PAX2 was confirmed using a heterologous DNA expression system. PAX2 recruits the adaptor protein PTIP and its associated histone methyltransferase (HMT) complex to Avpr2 promoter, imposing epigenetic marks on this region and throughout the coding sequence that modulate Avpr2 gene transcription. Reduction of PAX2 or PTIP protein levels by siRNA prevented histone lysine methylation and expression of Avpr2. ChIP using mouse or human kidneys determined that PAX2 is highly enriched in the AVPR2 promoter alongside PTIP and HMT proteins, leading to high levels of histone H3 lysine trimethylation within the promoter and throughout the gene. In conclusion, PAX2 provides locus specificity for PTIP, allowing the HMT complex to impart epigenetic changes at the Avpr2 locus and regulate Avpr2 transcription. These finding have major implications for understanding regulation of body water balance.NEW & NOTEWORTHY The transcription factor PAX2 plays an indispensable role in kidney development. In the adult kidney, we identified the first described protein this protein regulates. PAX2 and its interacting partner Pax transcription interacting protein recruit a histone methyltransferase complex to the promoter and epigentically regulate the expression of arginine vasopressin receptor 2, a protein that plays a crucial role in osmoregulation in the distal tubule.
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Affiliation(s)
- Saji Abraham
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Raghavendra Paknikar
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Samina Bhumbra
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Danny Luan
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Madhusudan Venkatareddy
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Christopher O'Connor
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Markus Bitzer
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
- Department of Internal Medicine, Veterans Administration, Veterans Affairs Medical Center, Ann Arbor, Michigan
| | - Robert A Fenton
- Department of Biomedicine and Health, Aarhus University, Aarhus, Denmark
| | - Toby Hurd
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Puneet Garg
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
- Department of Internal Medicine, Veterans Administration, Veterans Affairs Medical Center, Ann Arbor, Michigan
| | - Sanjeevkumar R Patel
- Nephrology Division of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
- Department of Internal Medicine, Veterans Administration, Veterans Affairs Medical Center, Ann Arbor, Michigan
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Baasch Christensen I, Cheng L, Brewer JR, Bartsch U, Fenton RA, Damkier HH, Praetorius J. Multiple Na,K-ATPase Subunits Colocalize in the Brush Border of Mouse Choroid Plexus Epithelial Cells. Int J Mol Sci 2021; 22:ijms22041569. [PMID: 33557294 PMCID: PMC7915972 DOI: 10.3390/ijms22041569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 01/29/2021] [Indexed: 01/24/2023] Open
Abstract
(1) Background: The unusual accumulation of Na,K-ATPase complexes in the brush border membrane of choroid plexus epithelial cells have intrigued researchers for decades. However, the full range of the expressed Na,K-ATPase subunits and their relation to the microvillus cytoskeleton remains unknown. (2) Methods: RT-PCR analysis, co-immunoprecipitation, native PAGE, mass spectrometry, and differential centrifugation were combined with high-resolution immunofluorescence histochemistry, proximity ligase assays, and stimulated emission depletion (STED) microscopy on mouse choroid plexus cells or tissues in order to resolve these issues. (3) Results: The choroid plexus epithelium expresses Na,K-ATPase subunits α1, α2, β1, β2, β3, and phospholemman. The α1, α2, β1, and β2, subunits are all localized to the brush border membrane, where they appear to form a complex. The ATPase complexes may stabilize in the brush border membrane via anchoring to microvillar actin indirectly through ankyrin-3 or directly via other co-precipitated proteins. Aquaporin 1 (AQP1) may form part of the proposed multi-protein complexes in contrast to another membrane protein, the Na-K-2Cl cotransporter 1 (NKCC1). NKCC1 expression seems necessary for full brush border membrane accumulation of the Na,K-ATPase in the choroid plexus. (4) Conclusion: A multitude of Na,K-ATPase subunits form molecular complexes in the choroid plexus brush border, which may bind to the cytoskeleton by various alternative actin binding proteins.
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Affiliation(s)
- Inga Baasch Christensen
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Lei Cheng
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Jonathan R. Brewer
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Southern Denmark, 5230 Odense, Denmark;
| | - Udo Bartsch
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
| | - Robert A. Fenton
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Helle H. Damkier
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
| | - Jeppe Praetorius
- Department of Biomedicine, Faculty of Health Science, Aarhus University, 8000 Aarhus, Denmark; (I.B.C.); (L.C.); (R.A.F.); (H.H.D.)
- Correspondence: ; Tel.: +45-61820576
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Abstract
The connexin 37 (Cx37) channel is clustered at gap junctions between cells in the renal vasculature or the renal tubule where it is abundant in basolateral cell interdigitations and infoldings of epithelial cells in the proximal tubule, thick ascending limb, distal convoluted tubule and collecting duct; however, physiological data regarding its role are limited. In this study, we investigated the role of Cx37 in fluid homeostasis using mice with a global deletion of Cx37 (Cx37-/- mice). Under baseline conditions, Cx37-/- had ~40% higher fluid intake associated with ~40% lower urine osmolality compared to wild-type (WT) mice. No differences were observed between genotypes in urinary adenosine triphosphate or prostaglandin E2, paracrine factors that alter renal water handling. After 18-hours of water deprivation, plasma aldosterone and urine osmolality increased significantly in Cx37-/- and WT mice; however, the latter remained ~375 mmol/kg lower in Cx37-/- mice, an effect associated with a more pronounced body weight loss despite higher urinary AVP/creatinine ratios compared to WT mice. Consistent with this, fluid intake in the first 3 hours after water deprivation was 37% greater in Cx37-/- vs WT mice. Cx37-/- mice showed significantly lower renal AQP2 abundance and AQP2 phosphorylation at serine 256 than WT mice in response to vehicle or dDAVP, suggesting a partial contribution of the kidney to the lower urine osmolality. The abundance and responses of the vasopressin V2 receptor, AQP3, NHE3, NKCC2, NCC, H+-ATPase, αENaC, γENaC or Na+/K+-ATPase were not significantly different between genotypes. In summary, these results demonstrate that Cx37 is important for body water handling.
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Affiliation(s)
- Jianxiang Xue
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Jessica A. Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | | | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
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Wu A, Wolley MJ, Wu Q, Gordon RD, Fenton RA, Stowasser M. The Cl−/HCO3− exchanger pendrin is downregulated during oral co-administration of exogenous mineralocorticoid and KCl in patients with primary aldosteronism. J Hum Hypertens 2020; 35:837-848. [DOI: 10.1038/s41371-020-00439-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 10/12/2020] [Accepted: 10/23/2020] [Indexed: 02/07/2023]
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Petrillo F, Fischer A, Chernyakov D, Esteva Font C, Poulsen SB, Krogager TP, Edemir B, Fenton RA. P0045GENETIC ABLATION OF NFAT5 IN THE PRINCIPAL CELLS OF THE COLLECTING DUCT LEADS TO A WATER HANDLING DEFECT. Nephrol Dial Transplant 2020. [DOI: 10.1093/ndt/gfaa144.p0045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background and Aims
Nuclear Factor of Activated T-Cells 5 (NFAT5), also called TonEBP/OREBP, helps protecting kidney cells from the stress of extracellular hypertonic challenge. In response to hypertonicity, NFAT5 rapidly translocates into the nucleus and enhances the transcription of osmoprotective genes. Mice lacking NFAT5 have embryonic lethality, with those surviving having severe renal atrophy and hydronephrosis. Overexpression of a dominant-negative NFAT5 in all epithelial cells of the thick ascending limb, distal tubule and collecting duct (CD) leads to an impairment in the urine concentration, with reduced expression of AQP2 and urea transporters UT-A1 and UT-A2. Here, we generated a novel mouse model to assess the role of NFAT5 in the water transporting principal cells of the CD.
Method
The mouse model was generated by breeding floxed NFAT5 mice with mice specifically expressing Cre recombinase in AQP2 expressing cells (NFAT5f/f-AQP2cre+/-). AQP2cre+/- mice served as controls. For renal function analysis, mice were kept in metabolic cages for 5 days and water intake, urinary volume, osmolality, and serum and urine electrolytes were evaluated. Mice were euthanized and the kidneys were used for western blot analysis.
Results
NFAT5f/f-AQP2cre+/- mice show a significant increase of 24 hour urine output compared to the control (KO: 6.267 ± 0.9367 µl/h/g BW vs WT: 0.9593 ± 0.0796 µl/h/g BW), a decrease in the urine osmolality (KO: 505.6 ± 107.6 mOsm/Kg H2O vs WT: 6205 ± 752.7 mOsm/Kg H2O) and urea concentration. After 3h and half intraperitoneal injection of dDAVP (1ug/kg) the osmolality was still significantly low in NFAT5f/f-AQP2cre+/- mice (KO: 743.7 ± 81.77 vs WT: 3342 ± 80.14 mOsm/Kg H2O), as well as after 8h water restriction (KO: 732.8 ± 24.90 vs WT: 3784 ± 450.9 mOsm/Kg H2O). Immunoblotting demonstrated a significant decrease in AQP2, AQP3 and AQP4 abundance in cortical kidney fractions and inner medulla. There were no differences in vasopressin V2 receptor (V2R) and AVP-regulated transporters NKCC2, ROMK and alpha-ENaC.
Conclusion
We demonstrate that NFAT5 ablation from AQP2-expressing cells results in a urinary concentration defect. NFAT5f/f-AQP2cre+/- mice have a hypoosmotic polyuria, without major effects on the AVP-V2R axis, suggesting Nephrogenic Diabetes Insipidus.
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Affiliation(s)
| | - Annika Fischer
- Martin-Luther-University Halle-Wittenberg, Department of Medicine, Hematology and Oncology, Halle (Saale), Germany
| | - Dmitry Chernyakov
- Martin-Luther-University Halle-Wittenberg, Department of Medicine, Hematology and Oncology, Halle (Saale), Germany
| | | | - Søren B Poulsen
- Aarhus University, Department of Biomedicine, Aarhus, Denmark
| | - Toke P Krogager
- Aarhus University, Department of Biomedicine, Aarhus, Denmark
| | - Bayram Edemir
- Martin-Luther-University Halle-Wittenberg, Department of Medicine, Hematology and Oncology, Halle (Saale), Germany
| | - Robert A Fenton
- Aarhus University, Department of Biomedicine, Aarhus, Denmark
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Fenton RA, Murali SK, Moeller HB. Advances in Aquaporin-2 trafficking mechanisms and their implications for treatment of water balance disorders. Am J Physiol Cell Physiol 2020; 319:C1-C10. [PMID: 32432927 DOI: 10.1152/ajpcell.00150.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In mammals, conservation of body water is critical for survival and is dependent on the kidneys ability to minimize water loss in the urine during periods of water deprivation. The collecting duct water channel aquaporin-2 (AQP2) plays an essential role in this homeostatic response by facilitating water reabsorption along osmotic gradients. The ability to increase the levels of AQP2 in the apical plasma membrane following an increase in plasma osmolality is a rate-limiting step in water reabsorption, a process that is tightly regulated by the antidiuretic hormone arginine vasopressin (AVP). In this review, the focus is on the role of the carboxyl-terminus of AQP2 as a key regulatory point for AQP2 trafficking. We provide an overview of AQP2 structure, disease-causing mutations in the AQP2 carboxyl-terminus, the role of post-translational modifications such as phosphorylation and ubiquitylation in the tail domain, and their implications for balanced trafficking of AQP2. Finally, we discuss how various modifications of the AQP2 tail facilitate selective protein:protein interactions that modulate the AQP2 trafficking mechanism.
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Affiliation(s)
- Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Sathish K Murali
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Hanne B Moeller
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
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Fenton RA, Murali SK, Kaji I, Akiba Y, Kaunitz JD, Kristensen TB, Poulsen SB, Dominguez Rieg JA, Rieg T. Adenylyl Cyclase 6 Expression Is Essential for Cholera Toxin-Induced Diarrhea. J Infect Dis 2020; 220:1719-1728. [PMID: 30624615 DOI: 10.1093/infdis/jiz013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Cholera toxin (CT)-induced diarrhea is mediated by cyclic adenosine monophosphate (cAMP)-mediated active Cl- secretion via the cystic fibrosis transmembrane conductance regulator (CFTR). Although the constitutive activation of adenylyl cyclase (AC) in response to CT is due to adenosine diphosphate ribosylation of the small G protein α-subunit activating CFTR with consequent secretory diarrhea, the AC isoform(s) involved remain unknown. METHODS We generated intestinal epithelial cell-specific adenylyl cyclase 6 (AC6) knockout mice to study its role in CT-induced diarrhea. RESULTS AC6 messenger RNA levels were the highest of all 9 membrane-bound AC isoforms in mouse intestinal epithelial cells. Intestinal epithelial-specific AC6 knockout mice (AC6loxloxVillinCre) had undetectable AC6 levels in small intestinal and colonic epithelial cells. No significant differences in fluid and food intake, plasma electrolytes, intestinal/colon anatomy and morphology, or fecal water content were observed between genotypes. Nevertheless, CT-induced fluid accumulation in vivo was completely absent in AC6loxloxVillinCre mice, associated with a lack of forskolin- and CT-induced changes in the short-circuit current (ISC) of the intestinal mucosa, impaired cAMP generation in acutely isolated small intestinal epithelial cells, and significantly impaired apical CFTR levels in response to forskolin. CONCLUSIONS AC6 is a novel target for the treatment of CT-induced diarrhea.
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Affiliation(s)
| | - Sathish K Murali
- Department of Biomedicine, Aarhus University, Denmark.,University of South Florida, Tampa
| | - Izumi Kaji
- Greater Los Angeles VA Healthcare System, California.,Department of Medicine, University of California, Los Angeles
| | - Yasutada Akiba
- Greater Los Angeles VA Healthcare System, California.,Department of Medicine, University of California, Los Angeles
| | - Jonathan D Kaunitz
- Greater Los Angeles VA Healthcare System, California.,Department of Medicine, University of California, Los Angeles
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Little R, Poulsen SB, Murali SK, Matchkov V, Fenton RA. Effects of Potassium Supplementation and the Accompanying Anion on Cardiovascular Parameters. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Poulsen SB, Cheng L, Penton D, Murali SK, Kortenoeven M, Loffing J, Fenton RA. Stimulation of the β2 adrenergic receptor rapidly increases phosphorylation of the Na
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‐Clcotransporter (NCC). FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.02200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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