1
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Cheung PW, Boukenna M, Babicz RSE, Mitra S, Kay A, Paunescu TC, Baylor N, Liu CCS, Nair AV, Bouley R, Brown D. Intracellular sites of AQP2 S256 phosphorylation identified using inhibitors of the AQP2 recycling itinerary. Am J Physiol Renal Physiol 2023; 324:F152-F167. [PMID: 36454701 PMCID: PMC9844975 DOI: 10.1152/ajprenal.00123.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/05/2022] Open
Abstract
Vasopressin (VP)-regulated aquaporin-2 (AQP2) trafficking between cytoplasmic vesicles and the plasma membrane of kidney principal cells is essential for water homeostasis. VP affects AQP2 phosphorylation at several serine residues in the COOH-terminus; among them, serine 256 (S256) appears to be a major regulator of AQP2 trafficking. Mutation of this serine to aspartic acid, which mimics phosphorylation, induces constitutive membrane expression of AQP2. However, the intracellular location(s) at which S256 phosphorylation occurs remains elusive. Here, we used strategies to block AQP2 trafficking at different cellular locations in LLC-PK1 cells and monitored VP-stimulated phosphorylation of S256 at these sites by immunofluorescence and Western blot analysis with phospho-specific antibodies. Using methyl-β-cyclodextrin, cold block or bafilomycin, and taxol, we blocked AQP2 at the plasma membrane, in the perinuclear trans-Golgi network, and in scattered cytoplasmic vesicles, respectively. Regardless of its cellular location, VP induced a significant increase in S256 phosphorylation, and this effect was not dependent on a functional microtubule cytoskeleton. To further investigate whether protein kinase A (PKA) was responsible for S256 phosphorylation in these cellular compartments, we created PKA-null cells and blocked AQP2 trafficking using the same procedures. We found that S256 phosphorylation was no longer increased compared with baseline, regardless of AQP2 localization. Taken together, our data indicate that AQP2 S256 phosphorylation can occur at the plasma membrane, in the trans-Golgi network, or in cytoplasmic vesicles and that this event is dependent on the expression of PKA in these cells.NEW & NOTEWORTHY Phosphorylation of aquaporin-2 by PKA at serine 256 (S256) occurs in various subcellular locations during its recycling itinerary, suggesting that the protein complex necessary for AQP2 S256 phosphorylation is present in these different recycling stations. Furthermore, we showed, using PKA-null cells, that PKA activity is required for vasopressin-induced AQP2 phosphorylation. Our data reveal a complex spatial pattern of intracellular AQP2 phosphorylation at S256, shedding new light on the role of phosphorylation in AQP2 membrane accumulation.
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Affiliation(s)
- Pui W Cheung
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Mey Boukenna
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Richard S E Babicz
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Shimontini Mitra
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Anna Kay
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Theodor C Paunescu
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Noah Baylor
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Chen-Chung Steven Liu
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Anil V Nair
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Richard Bouley
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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2
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Wagner K, Unger L, Salman MM, Kitchen P, Bill RM, Yool AJ. Signaling Mechanisms and Pharmacological Modulators Governing Diverse Aquaporin Functions in Human Health and Disease. Int J Mol Sci 2022; 23:1388. [PMID: 35163313 PMCID: PMC8836214 DOI: 10.3390/ijms23031388] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023] Open
Abstract
The aquaporins (AQPs) are a family of small integral membrane proteins that facilitate the bidirectional transport of water across biological membranes in response to osmotic pressure gradients as well as enable the transmembrane diffusion of small neutral solutes (such as urea, glycerol, and hydrogen peroxide) and ions. AQPs are expressed throughout the human body. Here, we review their key roles in fluid homeostasis, glandular secretions, signal transduction and sensation, barrier function, immunity and inflammation, cell migration, and angiogenesis. Evidence from a wide variety of studies now supports a view of the functions of AQPs being much more complex than simply mediating the passive flow of water across biological membranes. The discovery and development of small-molecule AQP inhibitors for research use and therapeutic development will lead to new insights into the basic biology of and novel treatments for the wide range of AQP-associated disorders.
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Affiliation(s)
- Kim Wagner
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia;
| | - Lucas Unger
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Mootaz M. Salman
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK;
- Oxford Parkinson’s Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Philip Kitchen
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Roslyn M. Bill
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Andrea J. Yool
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia;
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3
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Baltzer S, Bulatov T, Schmied C, Krämer A, Berger BT, Oder A, Walker-Gray R, Kuschke C, Zühlke K, Eichhorst J, Lehmann M, Knapp S, Weston J, von Kries JP, Süssmuth RD, Klussmann E. Aurora Kinase A Is Involved in Controlling the Localization of Aquaporin-2 in Renal Principal Cells. Int J Mol Sci 2022; 23:ijms23020763. [PMID: 35054947 PMCID: PMC8776063 DOI: 10.3390/ijms23020763] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/30/2021] [Accepted: 01/08/2022] [Indexed: 02/01/2023] Open
Abstract
The cAMP-dependent aquaporin-2 (AQP2) redistribution from intracellular vesicles into the plasma membrane of renal collecting duct principal cells induces water reabsorption and fine-tunes body water homeostasis. However, the mechanisms controlling the localization of AQP2 are not understood in detail. Using immortalized mouse medullary collecting duct (MCD4) and primary rat inner medullary collecting duct (IMCD) cells as model systems, we here discovered a key regulatory role of Aurora kinase A (AURKA) in the control of AQP2. The AURKA-selective inhibitor Aurora-A inhibitor I and novel derivatives as well as a structurally different inhibitor, Alisertib, prevented the cAMP-induced redistribution of AQP2. Aurora-A inhibitor I led to a depolymerization of actin stress fibers, which serve as tracks for the translocation of AQP2-bearing vesicles to the plasma membrane. The phosphorylation of cofilin-1 (CFL1) inactivates the actin-depolymerizing function of CFL1. Aurora-A inhibitor I decreased the CFL1 phosphorylation, accounting for the removal of the actin stress fibers and the inhibition of the redistribution of AQP2. Surprisingly, Alisertib caused an increase in actin stress fibers and did not affect CFL1 phosphorylation, indicating that AURKA exerts its control over AQP2 through different mechanisms. An involvement of AURKA and CFL1 in the control of the localization of AQP2 was hitherto unknown.
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Affiliation(s)
- Sandrine Baltzer
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (S.B.); (R.W.-G.); (C.K.); (K.Z.)
- Institute of Chemistry, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany; (T.B.); (R.D.S.)
| | - Timur Bulatov
- Institute of Chemistry, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany; (T.B.); (R.D.S.)
| | - Christopher Schmied
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (C.S.); (A.O.); (J.E.); (M.L.); (J.P.v.K.)
| | - Andreas Krämer
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany; (A.K.); (B.-T.B.); (S.K.)
- Structural Genomics Consortium (SGC), Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt am Main, Germany
- DKTK (German Translational Research Network), Partner Site Frankfurt/Mainz, 60590 Frankfurt am Main, Germany
| | - Benedict-Tilman Berger
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany; (A.K.); (B.-T.B.); (S.K.)
- Structural Genomics Consortium (SGC), Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt am Main, Germany
| | - Andreas Oder
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (C.S.); (A.O.); (J.E.); (M.L.); (J.P.v.K.)
| | - Ryan Walker-Gray
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (S.B.); (R.W.-G.); (C.K.); (K.Z.)
| | - Christin Kuschke
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (S.B.); (R.W.-G.); (C.K.); (K.Z.)
| | - Kerstin Zühlke
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (S.B.); (R.W.-G.); (C.K.); (K.Z.)
| | - Jenny Eichhorst
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (C.S.); (A.O.); (J.E.); (M.L.); (J.P.v.K.)
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (C.S.); (A.O.); (J.E.); (M.L.); (J.P.v.K.)
| | - Stefan Knapp
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany; (A.K.); (B.-T.B.); (S.K.)
- Structural Genomics Consortium (SGC), Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt am Main, Germany
- DKTK (German Translational Research Network), Partner Site Frankfurt/Mainz, 60590 Frankfurt am Main, Germany
- Frankfurt Cancer Institute, 60596 Frankfurt am Main, Germany
| | - John Weston
- JQuest Consulting, Carl-Orff-Weg 25, 65779 Kelkheim, Germany;
| | - Jens Peter von Kries
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (C.S.); (A.O.); (J.E.); (M.L.); (J.P.v.K.)
| | - Roderich D. Süssmuth
- Institute of Chemistry, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany; (T.B.); (R.D.S.)
| | - Enno Klussmann
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; (S.B.); (R.W.-G.); (C.K.); (K.Z.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, 10785 Berlin, Germany
- Correspondence: ; Tel.: +49-30-9406-2596
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4
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Chen L, Jung HJ, Datta A, Park E, Poll BG, Kikuchi H, Leo KT, Mehta Y, Lewis S, Khundmiri SJ, Khan S, Chou CL, Raghuram V, Yang CR, Knepper MA. Systems Biology of the Vasopressin V2 Receptor: New Tools for Discovery of Molecular Actions of a GPCR. Annu Rev Pharmacol Toxicol 2022; 62:595-616. [PMID: 34579536 PMCID: PMC10676752 DOI: 10.1146/annurev-pharmtox-052120-011012] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Systems biology can be defined as the study of a biological process in which all of the relevant components are investigated together in parallel to discover the mechanism. Although the approach is not new, it has come to the forefront as a result of genome sequencing projects completed in the first few years of the current century. It has elements of large-scale data acquisition (chiefly next-generation sequencing-based methods and protein mass spectrometry) and large-scale data analysis (big data integration and Bayesian modeling). Here we discuss these methodologies and show how they can be applied to understand the downstream effects of GPCR signaling, specifically looking at how the neurohypophyseal peptide hormone vasopressin, working through the V2 receptor and PKA activation, regulates the water channel aquaporin-2. The emerging picture provides a detailedframework for understanding the molecular mechanisms involved in water balance disorders, pointing the way to improved treatment of both polyuric disorders and water-retention disorders causing dilutional hyponatremia.
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Affiliation(s)
- Lihe Chen
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Hyun Jun Jung
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Arnab Datta
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
- Yenepoya Research Center, Yenepoya, Mangalore 575018, Karnataka, India
| | - Euijung Park
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Brian G Poll
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Hiroaki Kikuchi
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Kirby T Leo
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Yash Mehta
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Spencer Lewis
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Syed J Khundmiri
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Shaza Khan
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Chung-Lin Chou
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Viswanathan Raghuram
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Chin-Rang Yang
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20814, USA;
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5
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Noda Y, Sasaki S. Updates and Perspectives on Aquaporin-2 and Water Balance Disorders. Int J Mol Sci 2021; 22:ijms222312950. [PMID: 34884753 PMCID: PMC8657825 DOI: 10.3390/ijms222312950] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 12/31/2022] Open
Abstract
Ensuring the proper amount of water inside the body is essential for survival. One of the key factors in the maintenance of body water balance is water reabsorption in the collecting ducts of the kidney, a process that is regulated by aquaporin-2 (AQP2). AQP2 is a channel that is exclusively selective for water molecules and impermeable to ions or other small molecules. Impairments of AQP2 result in various water balance disorders, including nephrogenic diabetes insipidus (NDI), which is a disease characterized by a massive loss of water through the kidney and consequent severe dehydration. Dysregulation of AQP2 is also a cause of water retention with hyponatremia in heart failure, hepatic cirrhosis, and syndrome of inappropriate antidiuretic hormone secretion (SIADH). Antidiuretic hormone vasopressin is an upstream regulator of AQP2. Its binding to the vasopressin V2 receptor promotes AQP2 targeting to the apical membrane and thus enables water reabsorption. Tolvaptan, a vasopressin V2 receptor antagonist, is effective and widely used for water retention with hyponatremia. However, there are no studies showing improvement in hard outcomes or long-term prognosis. A possible reason is that vasopressin receptors have many downstream effects other than AQP2 function. It is expected that the development of drugs that directly target AQP2 may result in increased treatment specificity and effectiveness for water balance disorders. This review summarizes recent progress in studies of AQP2 and drug development challenges for water balance disorders.
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Affiliation(s)
- Yumi Noda
- Department of Nephrology, Nitobe Memorial Nakano General Hospital, Tokyo 164-8607, Japan
- Department of Nephrology, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
- Correspondence: ; Tel.: +81-3-3382-1231; Fax: +81-3-3382-1588
| | - Sei Sasaki
- Department of Nephrology, Cellular and Structural Physiology Laboratory, Tokyo Medical and Dental University, Tokyo 113-8519, Japan;
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6
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Olesen ETB, Fenton RA. Aquaporin 2 regulation: implications for water balance and polycystic kidney diseases. Nat Rev Nephrol 2021; 17:765-781. [PMID: 34211154 DOI: 10.1038/s41581-021-00447-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2021] [Indexed: 02/06/2023]
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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7
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Mortensen LA, Bistrup C, Jensen BL, Hinrichs GR. A mini-review of pharmacological strategies used to ameliorate polyuria associated with X-linked nephrogenic diabetes insipidus. Am J Physiol Renal Physiol 2020; 319:F746-F753. [PMID: 32924547 DOI: 10.1152/ajprenal.00339.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nephrogenic diabetes insipidus (NDI) is characterized by renal resistance to the antidiuretic hormone arginine vasopressin (AVP), which leads to polyuria, plasma hyperosmolarity, polydipsia, and impaired quality of living. Inherited forms are caused by X-linked loss-of-function mutations in the gene encoding the vasopressin 2 receptor (V2R) or autosomal recessive/dominant mutations in the gene encoding aquaporin 2 (AQP2). A common acquired form is lithium-induced NDI. AVP facilitates reabsorption of water through increased abundance and insertion of AQP2 in the apical membrane of principal cells in the collecting ducts. In X-linked NDI, V2R is dysfunctional, which leads to impaired water reabsorption. These patients have functional AQP2, and thus the challenge is to achieve AQP2 membrane insertion independently of V2R. The current treatment is symptomatic and is based on distally acting diuretics (thiazide or amiloride) and cyclooxygenase inhibitors (indomethacin). This mini-review covers published data from trials in preclinical in vivo models and a few human intervention studies to improve NDI by more causal approaches. Promising effects on NDI in preclinical studies have been demonstrated by the use of pharmacological approaches with secretin, Wnt5a, protein kinase A agonist, fluconazole, prostaglandin E2 EP2 and EP4 agonists, statins, metformin, and soluble prorenin receptor agonists. In patients, only casuistic reports have evaluated the effect of statins, phosphodiesterase inhibitors (rolipram and sildenafil), and the guanylate cyclase stimulator riociguat without amelioration of symptoms. It is concluded that there is currently no established intervention that causally improves symptoms or quality of life in patients with NDI. There is a need to collaborate to improve study quality and conduct formal trials.
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Affiliation(s)
- Line A Mortensen
- Department of Nephrology, Odense University Hospital, Odense, Denmark.,Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Claus Bistrup
- Department of Nephrology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Boye L Jensen
- Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Gitte R Hinrichs
- Department of Nephrology, Odense University Hospital, Odense, Denmark.,Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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Cyclin-Dependent Kinase 18 Controls Trafficking of Aquaporin-2 and Its Abundance through Ubiquitin Ligase STUB1, Which Functions as an AKAP. Cells 2020; 9:cells9030673. [PMID: 32164329 PMCID: PMC7140648 DOI: 10.3390/cells9030673] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/27/2020] [Accepted: 03/09/2020] [Indexed: 12/24/2022] Open
Abstract
Arginine-vasopressin (AVP) facilitates water reabsorption in renal collecting duct principal cells through regulation of the water channel aquaporin-2 (AQP2). The hormone binds to vasopressin V2 receptors (V2R) on the surface of the cells and stimulates cAMP synthesis. The cAMP activates protein kinase A (PKA), which initiates signaling that causes an accumulation of AQP2 in the plasma membrane of the cells facilitating water reabsorption from primary urine and fine-tuning of body water homeostasis. AVP-mediated PKA activation also causes an increase in the AQP2 protein abundance through a mechanism that involves dephosphorylation of AQP2 at serine 261 and a decrease in its poly-ubiquitination. However, the signaling downstream of PKA that controls the localization and abundance of AQP2 is incompletely understood. We carried out an siRNA screen targeting 719 kinase-related genes, representing the majority of the kinases of the human genome and analyzed the effect of the knockdown on AQP2 by high-content imaging and biochemical approaches. The screening identified 13 hits whose knockdown inhibited the AQP2 accumulation in the plasma membrane. Amongst the candidates was the so far hardly characterized cyclin-dependent kinase 18 (CDK18). Our further analysis revealed a hitherto unrecognized signalosome comprising CDK18, an E3 ubiquitin ligase, STUB1 (CHIP), PKA and AQP2 that controls the localization and abundance of AQP2. CDK18 controls AQP2 through phosphorylation at serine 261 and STUB1-mediated ubiquitination. STUB1 functions as an A-kinase anchoring protein (AKAP) tethering PKA to the protein complex and bridging AQP2 and CDK18. The modulation of the protein complex may lead to novel concepts for the treatment of disorders which are caused or are associated with dysregulated AQP2 and for which a satisfactory treatment is not available, e.g., hyponatremia, liver cirrhosis, diabetes insipidus, ADPKD or heart failure.
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9
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Baltzer S, Klussmann E. Small molecules for modulating the localisation of the water channel aquaporin-2-disease relevance and perspectives for targeting local cAMP signalling. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1049-1064. [PMID: 31300862 DOI: 10.1007/s00210-019-01686-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/23/2022]
Abstract
The tight spatial and temporal organisation of cyclic adenosine monophosphate (cAMP) signalling plays a key role in arginine-vasopressin (AVP)-mediated water reabsorption in renal collecting duct principal cells and in a plethora of other processes such as in the control of cardiac myocyte contractility. This review critically discusses in vitro- and cell-based screening strategies for the identification of small molecules that interfere with AVP/cAMP signalling in renal principal cells; it features phenotypic screening and approaches for targeting protein-protein interactions of A-kinase anchoring proteins (AKAPs), which organise local cAMP signalling hubs. The discovery of novel chemical entities for the modulation of local cAMP will not only provide tools for elucidating molecular mechanisms underlying cAMP signalling. Novel chemical entities can also serve as starting points for the development of novel drugs for the treatment of human diseases. Examples illustrate how screening for small molecules can pave the way to novel approaches for the treatment of certain forms of diabetes insipidus, a disease caused by defects in AVP-mediated water reabsorption.
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Affiliation(s)
- Sandrine Baltzer
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany. .,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany. .,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health and Vegetative Physiology, Berlin, Germany.
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10
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Vukićević T, Hinze C, Baltzer S, Himmerkus N, Quintanova C, Zühlke K, Compton F, Ahlborn R, Dema A, Eichhorst J, Wiesner B, Bleich M, Schmidt-Ott KM, Klussmann E. Fluconazole Increases Osmotic Water Transport in Renal Collecting Duct through Effects on Aquaporin-2 Trafficking. J Am Soc Nephrol 2019; 30:795-810. [PMID: 30988011 DOI: 10.1681/asn.2018060668] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 02/13/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Arginine-vasopressin (AVP) binding to vasopressin V2 receptors promotes redistribution of the water channel aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane of renal collecting duct principal cells. This pathway fine-tunes renal water reabsorption and urinary concentration, and its perturbation is associated with diabetes insipidus. Previously, we identified the antimycotic drug fluconazole as a potential modulator of AQP2 localization. METHODS We assessed the influence of fluconazole on AQP2 localization in vitro and in vivo as well as the drug's effects on AQP2 phosphorylation and RhoA (a small GTPase, which under resting conditions, maintains F-actin to block AQP2-bearing vesicles from reaching the plasma membrane). We also tested fluconazole's effects on water flow across epithelia of isolated mouse collecting ducts and on urine output in mice treated with tolvaptan, a VR2 blocker that causes a nephrogenic diabetes insipidus-like excessive loss of hypotonic urine. RESULTS Fluconazole increased plasma membrane localization of AQP2 in principal cells independent of AVP. It also led to an increased AQP2 abundance associated with alterations in phosphorylation status and ubiquitination as well as inhibition of RhoA. In isolated mouse collecting ducts, fluconazole increased transepithelial water reabsorption. In mice, fluconazole increased collecting duct AQP2 plasma membrane localization and reduced urinary output. Fluconazole also reduced urinary output in tolvaptan-treated mice. CONCLUSIONS Fluconazole promotes collecting duct AQP2 plasma membrane localization in the absence of AVP. Therefore, it might have utility in treating forms of diabetes insipidus (e.g., X-linked nephrogenic diabetes insipidus) in which the kidney responds inappropriately to AVP.
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Affiliation(s)
- Tanja Vukićević
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Christian Hinze
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany.,Department of Nephrology and Medical Intensive Care and.,Berlin Institute of Health, Berlin, Germany
| | - Sandrine Baltzer
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Nina Himmerkus
- Institute of Physiology, Christian Albrechts University Kiel, Kiel, Germany
| | | | - Kerstin Zühlke
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Friederike Compton
- Department of Nephrology and Medical Intensive Care and.,Berlin Institute of Health, Berlin, Germany
| | - Robert Ahlborn
- Information Technology Department, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Alessandro Dema
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Jenny Eichhorst
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Cellular Imaging, Berlin, Germany
| | - Burkhard Wiesner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Cellular Imaging, Berlin, Germany
| | - Markus Bleich
- Institute of Physiology, Christian Albrechts University Kiel, Kiel, Germany
| | - Kai M Schmidt-Ott
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany; .,Department of Nephrology and Medical Intensive Care and.,Berlin Institute of Health, Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany; .,German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany; and.,Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Vegetative Physiology, Berlin, Germany
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11
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Affiliation(s)
- Joseph G Verbalis
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC
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12
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Schrade K, Tröger J, Eldahshan A, Zühlke K, Abdul Azeez KR, Elkins JM, Neuenschwander M, Oder A, Elkewedi M, Jaksch S, Andrae K, Li J, Fernandes J, Müller PM, Grunwald S, Marino SF, Vukićević T, Eichhorst J, Wiesner B, Weber M, Kapiloff M, Rocks O, Daumke O, Wieland T, Knapp S, von Kries JP, Klussmann E. An AKAP-Lbc-RhoA interaction inhibitor promotes the translocation of aquaporin-2 to the plasma membrane of renal collecting duct principal cells. PLoS One 2018; 13:e0191423. [PMID: 29373579 PMCID: PMC5786306 DOI: 10.1371/journal.pone.0191423] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 01/04/2018] [Indexed: 01/13/2023] Open
Abstract
Stimulation of renal collecting duct principal cells with antidiuretic hormone (arginine-vasopressin, AVP) results in inhibition of the small GTPase RhoA and the enrichment of the water channel aquaporin-2 (AQP2) in the plasma membrane. The membrane insertion facilitates water reabsorption from primary urine and fine-tuning of body water homeostasis. Rho guanine nucleotide exchange factors (GEFs) interact with RhoA, catalyze the exchange of GDP for GTP and thereby activate the GTPase. However, GEFs involved in the control of AQP2 in renal principal cells are unknown. The A-kinase anchoring protein, AKAP-Lbc, possesses GEF activity, specifically activates RhoA, and is expressed in primary renal inner medullary collecting duct principal (IMCD) cells. Through screening of 18,431 small molecules and synthesis of a focused library around one of the hits, we identified an inhibitor of the interaction of AKAP-Lbc and RhoA. This molecule, Scaff10-8, bound to RhoA, inhibited the AKAP-Lbc-mediated RhoA activation but did not interfere with RhoA activation through other GEFs or activities of other members of the Rho family of small GTPases, Rac1 and Cdc42. Scaff10-8 promoted the redistribution of AQP2 from intracellular vesicles to the periphery of IMCD cells. Thus, our data demonstrate an involvement of AKAP-Lbc-mediated RhoA activation in the control of AQP2 trafficking.
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Affiliation(s)
- Katharina Schrade
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Jessica Tröger
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Adeeb Eldahshan
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Kerstin Zühlke
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | | | - Jonathan M. Elkins
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
| | | | - Andreas Oder
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Mohamed Elkewedi
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Sarah Jaksch
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | | | - Jinliang Li
- University of Miami Miller School of Medicine, Miami, United States of America
| | - Joao Fernandes
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Paul Markus Müller
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Stephan Grunwald
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Stephen F. Marino
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Tanja Vukićević
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Jenny Eichhorst
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Burkhard Wiesner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | | | - Michael Kapiloff
- University of Miami Miller School of Medicine, Miami, United States of America
| | - Oliver Rocks
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Oliver Daumke
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
| | - Thomas Wieland
- Institute of Experimental Pharmacology and Toxicology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Germany
| | - Stefan Knapp
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
- Institute for Pharmaceutical Chemistry and Buchmann Institute, Goethe University, Frankfurt, Germany
- DKTK (German Cancer Center Network), partner site Frankfurt/Main, Germany
| | | | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
- * E-mail:
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13
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Ser-261 phospho-regulation is involved in pS256 and pS269-mediated aquaporin-2 apical translocation. Biochem Biophys Res Commun 2017; 490:1039-1044. [PMID: 28668390 DOI: 10.1016/j.bbrc.2017.06.162] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 06/27/2017] [Indexed: 11/20/2022]
Abstract
Vasopressin catalyzes aquaporin-2 phosphorylation at several serine sites in the C-terminal region. Compared with Ser-256 and Ser-269 phosphorylation, the role of Ser-261 phospho-regulation on vasopressin-regulated AQP2 apical translocation is largely unknown. In addition, recent discovery of transcytotic apical delivery of AQP2 made the concept of its intracellular trafficking even more complicated. In this study, we evaluated how intact phospho-AQP2 signals fit with the transcytosis trafficking model in Madin-Darby canine kidney cells. PS256 and pS269 signals were intracellularly detectable in wild-type AQP2 at the beginning of forskolin stimulation (1 min). These phospho-signals were detectable in basolateral membranes even after 10 min of stimulation. AQP2 stably inserted in the apical membrane increased pS269 and decreased pS261 signals. In an NDI-causing mutant P262L-AQP2, in which Ser-261 phospho-regulation is impaired, the pS256 and pS269 signals were detectable in the basolateral membranes with increased pS261 signals after forskolin stimulation. These results suggest that Ser-261 phospho-regulation is involved in pS256- and pS269-mediated AQP2 apical translocation.
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Bimodal antagonism of PKA signalling by ARHGAP36. Nat Commun 2016; 7:12963. [PMID: 27713425 PMCID: PMC5059767 DOI: 10.1038/ncomms12963] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 08/19/2016] [Indexed: 02/07/2023] Open
Abstract
Protein kinase A is a key mediator of cAMP signalling downstream of G-protein-coupled receptors, a signalling pathway conserved in all eukaryotes. cAMP binding to the regulatory subunits (PKAR) relieves their inhibition of the catalytic subunits (PKAC). Here we report that ARHGAP36 combines two distinct inhibitory mechanisms to antagonise PKA signalling. First, it blocks PKAC activity via a pseudosubstrate motif, akin to the mechanism employed by the protein kinase inhibitor proteins. Second, it targets PKAC for rapid ubiquitin-mediated lysosomal degradation, a pathway usually reserved for transmembrane receptors. ARHGAP36 thus dampens the sensitivity of cells to cAMP. We show that PKA inhibition by ARHGAP36 promotes derepression of the Hedgehog signalling pathway, thereby providing a simple rationale for the upregulation of ARHGAP36 in medulloblastoma. Our work reveals a new layer of PKA regulation that may play an important role in development and disease.
Protein kinase A (PKA) is a key mediator of cyclic AMP signalling. Here, Eccles et al. show that ARHGAP36 antagonizes PKA by acting as a kinase inhibitor and targeting the catalytic subunit for endolysosomal degradation, thus reducing sensitivity of cells to cAMP and promoting Hedgehog signalling.
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15
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Vukićević T, Schulz M, Faust D, Klussmann E. The Trafficking of the Water Channel Aquaporin-2 in Renal Principal Cells-a Potential Target for Pharmacological Intervention in Cardiovascular Diseases. Front Pharmacol 2016; 7:23. [PMID: 26903868 PMCID: PMC4749865 DOI: 10.3389/fphar.2016.00023] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/25/2016] [Indexed: 01/13/2023] Open
Abstract
Arginine-vasopressin (AVP) stimulates the redistribution of water channels, aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane of renal collecting duct principal cells. By this AVP directs 10% of the water reabsorption from the 170 L of primary urine that the human kidneys produce each day. This review discusses molecular mechanisms underlying the AVP-induced redistribution of AQP2; in particular, it provides an overview over the proteins participating in the control of its localization. Defects preventing the insertion of AQP2 into the plasma membrane cause diabetes insipidus. The disease can be acquired or inherited, and is characterized by polyuria and polydipsia. Vice versa, up-regulation of the system causing a predominant localization of AQP2 in the plasma membrane leads to excessive water retention and hyponatremia as in the syndrome of inappropriate antidiuretic hormone secretion (SIADH), late stage heart failure or liver cirrhosis. This article briefly summarizes the currently available pharmacotherapies for the treatment of such water balance disorders, and discusses the value of newly identified mechanisms controlling AQP2 for developing novel pharmacological strategies. Innovative concepts for the therapy of water balance disorders are required as there is a medical need due to the lack of causal treatments.
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Affiliation(s)
- Tanja Vukićević
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Maike Schulz
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Dörte Faust
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz AssociationBerlin, Germany; German Centre for Cardiovascular ResearchBerlin, Germany
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16
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Yu X, Li F, Klussmann E, Stallone JN, Han G. G protein-coupled estrogen receptor 1 mediates relaxation of coronary arteries via cAMP/PKA-dependent activation of MLCP. Am J Physiol Endocrinol Metab 2014; 307:E398-407. [PMID: 25005496 DOI: 10.1152/ajpendo.00534.2013] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Activation of GPER exerts a protective effect in hypertension and ischemia-reperfusion models and relaxes arteries in vitro. However, our understanding of the mechanisms of GPER-mediated vascular regulation is far from complete. In the current study, we tested the hypothesis that GPER-induced relaxation of porcine coronary arteries is mediated via cAMP/PKA signaling. Our findings revealed that vascular relaxation to the selective GPER agonist G-1 (0.3-3 μM) was associated with increased cAMP production in a concentration-dependent manner. Furthermore, inhibition of adenylyl cyclase (AC) with SQ-22536 (100 μM) or of PKA activity with either Rp-8-CPT-cAMPS (5 μM) or PKI (5 μM) attenuated G-1-induced relaxation of coronary arteries preconstricted with PGF2α (1 μM). G-1 also increased PKA activity in cultured coronary artery smooth muscle cells (SMCs). To determine downstream signals of the cAMP/PKA cascade, we measured RhoA activity in cultured human and porcine coronary SMCs and myosin-light chain phosphatase (MLCP) activity in these artery rings by immunoblot analysis of phosphorylation of myosin-targeting subunit protein-1 (p-MYPT-1; the MLCP regulatory subunit). G-1 decreased PGF2α-induced p-MYPT-1, whereas Rp-8-CPT-cAMPS prevented this inhibitory effect of G-1. Similarly, G-1 inhibited PGF2α-induced phosphorylation of MLC in coronary SMCs, and this inhibitory effect was also reversed by Rp-8-CPT-cAMPS. RhoA activity was downregulated by G-1, whereas G36 (GPER antagonist) restored RhoA activity. Finally, FMP-API-1 (100 μM), an inhibitor of the interaction between PKA and A-kinase anchoring proteins (AKAPs), attenuated the effect of G-1 on coronary artery relaxation and p-MYPT-1. These findings demonstrate that localized cAMP/PKA signaling is involved in GPER-mediated coronary vasodilation by activating MLCP via inhibition of RhoA pathway.
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Affiliation(s)
- Xuan Yu
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas
| | - Fen Li
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas; College of Life Science, Henan Normal University, Xinxiang, Henan Province, China; and
| | - Enno Klussmann
- Anchored Signaling, Max-Delbrück-Centrum für Molekulare Medizin Berlin-Buch, Berlin, Germany
| | - John N Stallone
- Women's Health Division, Michael E. DeBakey Institute, and Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas
| | - Guichun Han
- Women's Health Division, Michael E. DeBakey Institute, and Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas;
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17
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Nomura N, Nunes P, Bouley R, Nair AV, Shaw S, Ueda E, Pathomthongtaweechai N, Lu HAJ, Brown D. High-throughput chemical screening identifies AG-490 as a stimulator of aquaporin 2 membrane expression and urine concentration. Am J Physiol Cell Physiol 2014; 307:C597-605. [PMID: 24944200 DOI: 10.1152/ajpcell.00154.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A reduction or loss of plasma membrane aquaporin 2 (AQP2) in kidney principal cells due to defective vasopressin (VP) signaling through the VP receptor causes excessive urine production, i.e., diabetes insipidus. The amount of AQP2 on the plasma membrane is regulated by a balance of exocytosis and endocytosis and is the rate limiting step for water reabsorption in the collecting duct. We describe here a systematic approach using high-throughput screening (HTS) followed by in vitro and in vivo assays to discover novel compounds that enhance vasopressin-independent AQP2 membrane expression. We performed initial chemical library screening with a high-throughput exocytosis fluorescence assay using LLC-PK1 cells expressing soluble secreted yellow fluorescent protein and AQP2. Thirty-six candidate exocytosis enhancers were identified. These compounds were then rescreened in AQP2-expressing cells to determine their ability to increase AQP2 membrane accumulation. Effective drugs were then applied to kidney slices in vitro. Three compounds, AG-490, β-lapachone, and HA14-1 increased AQP2 membrane accumulation in LLC-PK1 cells, and both AG-490 and β-lapachone were also effective in MDCK cells and principal cells in rat kidney slices. Finally, one compound, AG-490 (an EGF receptor and JAK-2 kinase inhibitor), decreased urine volume and increased urine osmolality significantly in the first 2-4 h after a single injection into VP-deficient Brattleboro rats. In conclusion, we have developed a systematic procedure for identifying new compounds that modulate AQP2 trafficking using initial HTS followed by in vitro assays in cells and kidney slices, and concluding with in vivo testing in an animal model.
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Affiliation(s)
- Naohiro Nomura
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Paula Nunes
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Richard Bouley
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Anil V Nair
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Stanley Shaw
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and
| | - Erica Ueda
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and
| | - Nutthapoom Pathomthongtaweechai
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Hua A Jenny Lu
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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Abstract
PURPOSE OF REVIEW Aquaporin-2 (AQP2) water channels in principal cells of the kidney collecting duct are essential for urine concentration. Due to application of modern technologies, progress in our understanding of AQP2 has accelerated in recent years. In this article, we highlight some of the new insights into AQP2 function that have developed recently, with particular focus on the cell biological aspects of AQP2 regulation. RECENT FINDINGS AQP2 is subjected to a number of regulated modifications, including phosphorylation and ubiquitination, which are important for AQP2 function, cellular localization and degradation. AQP2 is likely internalized via clathrin and non-clathrin-mediated endocytosis. Regulation of AQP2 endocytosis, in addition to exocytosis, is a vital mechanism in determining overall AQP2 membrane abundance. AQP2 is associated with regulated membrane microdomains. Studies using membrane cholesterol depleting reagents, for example statins, have supported the role of membrane rafts in regulation of AQP2 trafficking. Noncanonical roles for AQP2, for example in epithelial cell migration, are emerging. SUMMARY AQP2 function and thus urine concentration is dependent on a variety of cell signalling mechanisms, posttranslational modification and interplay between AQP2 and its lipid environment. This complexity of regulation allows fine-tuning of AQP2 function and thus body water homeostasis.
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Brown D, Jenny Lu HA. Aquaporin-2 Inhibitors: Fishing in the Chemical Pool. J Am Soc Nephrol 2013; 24:685-6. [DOI: 10.1681/asn.2013030243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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