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Hagströmer CJ, Hyld Steffen J, Kreida S, Al-Jubair T, Frick A, Gourdon P, Törnroth-Horsefield S. Structural and functional analysis of aquaporin-2 mutants involved in nephrogenic diabetes insipidus. Sci Rep 2023; 13:14674. [PMID: 37674034 PMCID: PMC10482962 DOI: 10.1038/s41598-023-41616-1] [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: 03/14/2023] [Accepted: 08/29/2023] [Indexed: 09/08/2023] Open
Abstract
Aquaporins are water channels found in the cell membrane, where they allow the passage of water molecules in and out of the cells. In the kidney collecting duct, arginine vasopressin-dependent trafficking of aquaporin-2 (AQP2) fine-tunes reabsorption of water from pre-urine, allowing precise regulation of the final urine volume. Point mutations in the gene for AQP2 may disturb this process and lead to nephrogenic diabetes insipidus (NDI), whereby patients void large volumes of highly hypo-osmotic urine. In recessive NDI, mutants of AQP2 are retained in the endoplasmic reticulum due to misfolding. Here we describe the structural and functional characterization of three AQP2 mutations associated with recessive NDI: T125M and T126M, situated close to a glycosylation site and A147T in the transmembrane region. Using a proteoliposome assay, we show that all three mutants permit the transport of water. The crystal structures of T125M and T126M together with biophysical characterization of all three mutants support that they retain the native structure, but that there is a significant destabilization of A147T. Our work provides unique molecular insights into the mechanisms behind recessive NDI as well as deepens our understanding of how misfolded proteins are recognized by the ER quality control system.
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Affiliation(s)
| | - Jonas Hyld Steffen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stefan Kreida
- Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Tamim Al-Jubair
- Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Anna Frick
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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2
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Münch J, Goodyer PR, Wagner CA. Tubular Diseases and Stones Seen From Pediatric and Adult Nephrology Perspectives. Semin Nephrol 2023; 43:151437. [PMID: 37968178 DOI: 10.1016/j.semnephrol.2023.151437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
The tubular system of the kidneys is a complex series of morphologic and functional units orchestrating the content of tubular fluid as it flows along the nephron and collecting ducts. Renal tubules maintain body water, regulate electrolytes and acid-base balance, reabsorb precious organic solutes, and eliminate specific metabolites, toxins, and drugs. In addition, decisive mechanisms to adjust blood pressure are governed by the renal tubules. Genetic as well as acquired disorders of these tubular functions may cause serious diseases that manifest both in childhood and adulthood. This article addresses a selection of tubulopathies and the underlying pathomechanisms, while highlighting the important differences in pediatric and adult nephrology care. These range from rare monogenic conditions such as nephrogenic diabetes insipidus, cystinosis, and Bartter syndrome that present in childhood, to the genetic and acquired tubular pathologies causing hypertension or nephrolithiasis that are more prevalent in adults. Both pediatric and adult nephrologists must be aware of these conditions and the age-dependent manifestations that warrant close interaction between the two subspecialties.
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Affiliation(s)
- Johannes Münch
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Institute of Human Genetics, University of Zurich, Zurich, Switzerland; National Center of Competence in Research, NCCR Kidney.CH, Switzerland
| | - Paul R Goodyer
- McGill University Health Centre, Montreal, Quebec, Canada
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research, NCCR Kidney.CH, Switzerland.
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3
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Bahouth SW, Nooh MM, Mancarella S. Involvement of SAP97 anchored multiprotein complexes in regulating cardiorenal signaling and trafficking networks. Biochem Pharmacol 2023; 208:115406. [PMID: 36596415 DOI: 10.1016/j.bcp.2022.115406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 01/02/2023]
Abstract
SAP97 is a member of the MAGUK family of proteins, but unlike other MAGUK proteins that are selectively expressed in the CNS, SAP97 is also expressed in peripheral organs, like the heart and kidneys. SAP97 has several protein binding cassettes, and this review will describe their involvement in creating SAP97-anchored multiprotein networks. SAP97-anchored networks localized at the inner leaflet of the cell membrane play a major role in trafficking and targeting of membrane G protein-coupled receptors (GPCR), channels, and structural proteins. SAP97 plays a major role in compartmentalizing voltage gated sodium and potassium channels to specific cellular compartments of heart cells. SAP97 undergoes extensive alternative splicing. These splice variants give rise to different SAP97 isoforms that alter its cellular localization, networking, signaling and trafficking effects. Regarding GPCR, SAP97 binds to the β1-adrenergic receptor and recruits AKAP5/PKA and PDE4D8 to create a multiprotein complex that regulates trafficking and signaling of cardiac β1-AR. In the kidneys, SAP97 anchored networks played a role in trafficking of aquaporin-2 water channels. Cardiac specific ablation of SAP97 (SAP97-cKO) resulted in cardiac hypertrophy and failure in aging mice. Similarly, instituting transverse aortic constriction (TAC) in young SAP97 c-KO mice exacerbated TAC-induced cardiac remodeling and dysfunction. These findings highlight a critical role for SAP97 in the pathophysiology of a number of cardiac and renal diseases, suggesting that SAP97 is a relevant target for drug discovery.
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Affiliation(s)
- Suleiman W Bahouth
- Department of Pharmacology, Addiction Science and Toxicology, The University of Tennessee-Health Sciences Center, Memphis, TN, United States.
| | - Mohammed M Nooh
- Department of Biochemistry, Faculty of Pharmacy Cairo University, Cairo, Egypt and Biochemistry Department, Faculty of Pharmacy, October 6 University, Giza, Egypt
| | - Salvatore Mancarella
- Department of Physiology, The University of Tennessee-Health Sciences Center, Memphis, TN, United States
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4
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Hureaux M, Vargas-Poussou R. Genetic basis of nephrogenic diabetes insipidus. Mol Cell Endocrinol 2023; 560:111825. [PMID: 36460218 DOI: 10.1016/j.mce.2022.111825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 12/02/2022]
Abstract
Nephrogenic diabetes insipidus is defined as an inability to concentrate urine due to a complete or partial alteration of the renal tubular response to arginine vasopressin hormone, resulting in excessive diluted urine excretion. Hereditary forms are caused by molecular defects in the genes encoding either of the two main renal effectors of the arginine vasopressin pathway: the AVPR2 gene, which encodes for the type 2 vasopressin receptor, or the AQP2 gene, which encodes for the water channel aquaporin-2. About 90% of cases of nephrogenic diabetes insipidus result from loss-of-function variants in the AVPR2 gene, which are inherited in a X-linked recessive manner. The remaining 10% of cases result from loss-of-function variants in the AQP2 gene, which can be inherited in either a recessive or a dominant manner. The main symptoms of the disease are polyuria, chronic dehydration and hypernatremia. These symptoms usually occur in the first year of life, although some patients present later. Diagnosis is based on abnormal response in urinary osmolality after water restriction and/or administration of exogenous vasopressin. Treatment involves ensuring adequate water intake on demand, possibly combined with thiazide diuretics, non-steroidal anti-inflammatory drugs, and a low-salt and protein diet. In this review, we provide an update on current understanding of the molecular basis of inherited nephrogenic insipidus diabetes.
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Affiliation(s)
- Marguerite Hureaux
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Department of Genetics, France and University of Paris Cité, Paris, France; Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France
| | - Rosa Vargas-Poussou
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Department of Genetics, France and University of Paris Cité, Paris, France; Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France.
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5
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Lu HAJ, He J. Aquaporins in Diabetes Insipidus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:267-279. [PMID: 36717500 DOI: 10.1007/978-981-19-7415-1_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Disruption of water and electrolyte balance is frequently encountered in clinical medicine. Regulating water metabolism is critically important. Diabetes insipidus (DI) presented with excessive water loss from the kidney is a major disorder of water metabolism. To understanding the molecular and cellular mechanisms and pathophysiology of DI and rationales of clinical management of DI is important for both research and clinical practice. This chapter will first review various forms of DI focusing on central diabetes insipidus (CDI) and nephrogenic diabetes insipidus (NDI). This is followed by a discussion of regulatory mechanisms underlying CDI and NDI, with a focus on the regulatory axis of vasopressin, vasopressin receptor 2 (V2R) and the water channel molecule, aquaporin 2 (AQP2). The clinical manifestation, diagnosis, and management of various forms of DI will also be discussed with highlights of some of the latest therapeutic strategies that are developed from in vitro experiments and animal studies.
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Affiliation(s)
- H A Jenny Lu
- Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Jinzhao He
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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6
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AQP2 trafficking in health and diseases: an updated overview. Int J Biochem Cell Biol 2022; 149:106261. [DOI: 10.1016/j.biocel.2022.106261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 11/23/2022]
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7
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Dutta A, Das M. Deciphering the Role of Aquaporins in Metabolic Diseases: A Mini Review. Am J Med Sci 2022; 364:148-162. [DOI: 10.1016/j.amjms.2021.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 06/16/2021] [Accepted: 10/21/2021] [Indexed: 12/23/2022]
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8
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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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9
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AQP2: Mutations Associated with Congenital Nephrogenic Diabetes Insipidus and Regulation by Post-Translational Modifications and Protein-Protein Interactions. Cells 2020; 9:cells9102172. [PMID: 32993088 PMCID: PMC7599609 DOI: 10.3390/cells9102172] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 09/22/2020] [Accepted: 09/25/2020] [Indexed: 02/07/2023] Open
Abstract
, the molecular defects in the AVPR2 and AQP2 mutants, post-translational modifications (i.e., phosphorylation, ubiquitination, and glycosylation) and various protein-protein interactions that regulate phosphorylation, ubiquitination, tetramerization, trafficking, stability, and degradation of AQP2.
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10
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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] [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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11
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Ma L, Wu D, Wang X, Yang Y. A Case of Congenital Nephrogenic Diabetes Insipidus Caused by Thr108Met Variant of Aquaporin 2. Front Pediatr 2020; 8:15. [PMID: 32083042 PMCID: PMC7002472 DOI: 10.3389/fped.2020.00015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/13/2020] [Indexed: 12/14/2022] Open
Abstract
Congenital nephrogenic diabetes insipidus (CNDI) is a rare renal disorder caused by mutations in arginine vasopressin receptor 2 (AVPR2) or aquaporin 2 (AQP2). The clinical signs of CNDI include polyuria, compensatory polydipsia, dehydration, electrolyte disorder, and developmental retardation without prompt treatment. In this study we report a rare case of CNDI caused by a single base transition in AQP2 gene. A 4.5 years old male patient suffered from oral dryness, polydipsia, and polyuria for more than 3 years. Laboratory examinations showed hypernatremia, hyperchloremia, and decreased urine osmolality and specific gravity. Ultrasound and MRI found bilateral upper ureteral dilatation and hydronephrosis. Furthermore, sequencing analysis found a C>T transition leading to a T108M missense mutation of AQP2. The patient was given low sodium diet and treated with hydrochlorothiazide followed by amiloride with indomethacin. The patient's clinical course improved remarkably after 1 year of treatment. This study reports the first case of CNDI featuring T108M missense mutation alone. These findings demonstrate a causative role of T108M mutation for CNDI and contribute to the mechanistic understanding of CNDI disease process.
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Affiliation(s)
- Lina Ma
- Department of Pediatric Nephrology, Lanzhou University Second Hospital, Lanzhou, China.,Department of Nephrology, Gansu Children's Hospital, Lanzhou, China
| | - Dengyan Wu
- Department of Pediatric Nephrology, Lanzhou University Second Hospital, Lanzhou, China.,Department of Nephrology, Gansu Children's Hospital, Lanzhou, China
| | - Xingmin Wang
- Nantong Institute of Genetics and Reproductive Medicine, Nantong Maternity and Child Healthcare Hospital, Nantong University, Nantong, China.,School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yonghong Yang
- Department of Pediatric Nephrology, Lanzhou University Second Hospital, Lanzhou, China.,Department of Nephrology, Gansu Children's Hospital, Lanzhou, China
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12
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TRPC3 determines osmosensitive [Ca2+]i signaling in the collecting duct and contributes to urinary concentration. PLoS One 2019; 14:e0226381. [PMID: 31851715 PMCID: PMC6919627 DOI: 10.1371/journal.pone.0226381] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/25/2019] [Indexed: 02/07/2023] Open
Abstract
It is well-established that the kidney collecting duct (CD) plays a central role in regulation of systemic water homeostasis. Aquaporin 2 (AQP2)-dependent water reabsorption in the CD critically depends on the arginine vasopressin (AVP) antidiuretic input and the presence of a favorable osmotic gradient at the apical plasma membrane with tubular lumen being hypotonic compared to the cytosol. This osmotic difference creates a mechanical force leading to an increase in [Ca2+]i in CD cells. The significance of the osmosensitive [Ca2+]i signaling for renal water transport and urinary concentration remain unknown. To examine molecular mechanism and physiological relevance of osmosensitivity in the CD, we implemented simultaneous direct measurements of [Ca2+]i dynamics and the rate of cell swelling as a readout of the AQP2-dependent water reabsorption in freshly isolated split-opened CDs of wild type and genetically manipulated animals and combined this with immunofluorescent detection of AVP-induced AQP2 trafficking and assessment of systemic water balance. We identified the critical role of the Ca2+-permeable TRPC3 channel in osmosensitivity and water permeability in the CD. We further demonstrated that TRPC3 -/- mice exhibit impaired urinary concentration, larger urinary volume and a greater weight loss in response to water deprivation despite increased AVP levels and AQP2 abundance. TRPC3 deletion interfered with AQP2 translocation to the plasma membrane in response to water deprivation. In summary, we provide compelling multicomponent evidence in support of a critical contribution of TRPC3 in the CD for osmosensitivity and renal water handling.
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13
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Nooh MM, Kale A, Bahouth SW. Involvement of PDZ-SAP97 interactions in regulating AQP2 translocation in response to vasopressin in LLC-PK 1 cells. Am J Physiol Renal Physiol 2019; 317:F375-F387. [PMID: 31141395 PMCID: PMC6732448 DOI: 10.1152/ajprenal.00228.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 05/20/2019] [Accepted: 05/21/2019] [Indexed: 11/22/2022] Open
Abstract
Arginine-vasopressin (AVP)-mediated translocation of aquaporin-2 (AQP2) protein-forming water channels from storage vesicles to the membrane of renal collecting ducts is critical for the renal conservation of water. The type-1 PDZ-binding motif (PBM) in AQP2, "GTKA," is a critical barcode for its translocation, but its precise role and that of its interacting protein partners in this process remain obscure. We determined that synapse-associated protein-97 (SAP97), a membrane-associated guanylate kinase protein involved in establishing epithelial cell polarity, was an avid binding partner to the PBM of AQP2. The role of PBM and SAP97 on AQP2 redistribution in response to AVP was assessed in LLC-PK1 renal collecting cells by confocal microscopy and cell surface biotinylation techniques. These experiments indicated that distribution of AQP2 and SAP97 overlapped in the kidneys and LLC-PK1 cells and that knockdown of SAP97 inhibited the translocation of AQP2 in response to AVP. Binding between AQP2 and SAP97 was mediated by specific interactions between the second PDZ of SAP97 and PBM of AQP2. Mechanistically, inactivation of the PBM of AQP2, global delocalization of PKA, or knockdown of SAP97 inhibited AQP2 translocation as well as AVP- and forskolin-mediated phosphorylation of Ser256 in AQP2, which serves as the major translocation barcode of AQP2. These results suggest that the targeting of PKA to the microdomain of AQP2 via SAP97-AQP2 interactions in association with cross-talk between two barcodes in AQP2, namely, the PBM and phospho-Ser256, plays an important role in the translocation of AQP2 in the kidney.
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Affiliation(s)
- Mohammed M Nooh
- Department of Pharmacology, The University of Tennessee Health Sciences Center, Memphis, Tennessee
- Department of Biochemistry, Faculty of Pharmacy Cairo University, Cairo, Egypt
| | - Ajay Kale
- Department of Pharmacology, School of Pharmacy, University of Louisiana at Monroe, Monroe, Louisiana
| | - Suleiman W Bahouth
- Department of Pharmacology, The University of Tennessee Health Sciences Center, Memphis, Tennessee
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14
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Peces R, Mena R, Peces C, Santos-Simarro F, Fernández L, Afonso S, Lapunzina P, Selgas R, Nevado J. Severe congenital nephrogenic diabetes insipidus in a compound heterozygote with a new large deletion of the AQP2 gene. A case report. Mol Genet Genomic Med 2019; 7:e00568. [PMID: 30784238 PMCID: PMC6465731 DOI: 10.1002/mgg3.568] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 10/28/2018] [Accepted: 12/02/2018] [Indexed: 12/23/2022] Open
Abstract
Background Congenital nephrogenic diabetes insipidus (NDI) is a rare condition characterized by severe polyuria, due to the inability of the kidneys to concentrate urine in response to arginine vasopressin (AVP). In the majority of the cases, the disease shows an X‐linked inherited pattern, although an autosomal recessive inheritance was also observed. Methods We report a patient with a severe NDI diagnosed during the neonatal period. Because the patient was female without a family history of congenital NDI, her disease was thought to exhibit an autosomal recessive form. Results A full mutation analysis of AVP receptor 2 (AVPR2; MIM#300538) gene showed no mutations. However, direct Sanger sequencing of the aquaporin 2 (AQP2) revealed an apparently homozygous mutation at nucleotide position NM_000486.5:c.374C>T (p.Thr125Met) in exon 2. Further customized multiplex ligation‐dependent probe amplification (MLPA), single‐nucleotide polymorphism (SNP) array analysis, and long‐range polymerase chain reaction (PCR) followed by Sanger sequencing showed a heterozygous exonic deletion comprising exons 2, 3, and partially 4 of AQP2. Conclusion This is the first case of a compound heterozygote patient with a missense mutation involving NM_000486.5:exon2:c.374C>T (p.Thr125Met) and a gross deletion of at least exons 2, 3, and partially 4 on the AQP2 to present with a severe NDI phenotype.
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Affiliation(s)
- Ramón Peces
- Nephrology Department, La Paz University Hospital, IdiPAZ, Autonomous University, Madrid, Spain
| | - Rocío Mena
- La Paz University Hospital, Medical and Molecular Genetics Institute (INGEMM), IdiPAZ, Madrid, Spain.,Basic Research Center in the Rare Diseases Network (CIBERER), Madrid, Spain
| | - Carlos Peces
- Information Technology Area, SESCAM, Toledo, Spain
| | - Fernando Santos-Simarro
- La Paz University Hospital, Medical and Molecular Genetics Institute (INGEMM), IdiPAZ, Madrid, Spain.,Basic Research Center in the Rare Diseases Network (CIBERER), Madrid, Spain
| | - Luis Fernández
- La Paz University Hospital, Medical and Molecular Genetics Institute (INGEMM), IdiPAZ, Madrid, Spain.,Basic Research Center in the Rare Diseases Network (CIBERER), Madrid, Spain
| | - Sara Afonso
- Nephrology Department, La Paz University Hospital, IdiPAZ, Autonomous University, Madrid, Spain
| | - Pablo Lapunzina
- La Paz University Hospital, Medical and Molecular Genetics Institute (INGEMM), IdiPAZ, Madrid, Spain.,Basic Research Center in the Rare Diseases Network (CIBERER), Madrid, Spain
| | - Rafael Selgas
- Nephrology Department, La Paz University Hospital, IdiPAZ, Autonomous University, Madrid, Spain
| | - Julián Nevado
- La Paz University Hospital, Medical and Molecular Genetics Institute (INGEMM), IdiPAZ, Madrid, Spain.,Basic Research Center in the Rare Diseases Network (CIBERER), Madrid, Spain
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15
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Calvanese L, D'Auria G, Vangone A, Falcigno L, Oliva R. Structural Basis for Mutations of Human Aquaporins Associated to Genetic Diseases. Int J Mol Sci 2018; 19:E1577. [PMID: 29799470 PMCID: PMC6032259 DOI: 10.3390/ijms19061577] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/17/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023] Open
Abstract
Aquaporins (AQPs) are among the best structural-characterized membrane proteins, fulfilling the role of allowing water flux across cellular membranes. Thus far, 34 single amino acid polymorphisms have been reported in HUMSAVAR for human aquaporins as disease-related. They affect AQP2, AQP5 and AQP8, where they are associated with nephrogenic diabetes insipidus, keratoderma and colorectal cancer, respectively. For half of these mutations, although they are mostly experimentally characterized in their dysfunctional phenotypes, a structural characterization at a molecular level is still missing. In this work, we focus on such mutations and discuss what the structural defects are that they appear to cause. To achieve this aim, we built a 3D molecular model for each mutant and explored the effect of the mutation on all of their structural features. Based on these analyses, we could collect the structural defects of all the pathogenic mutations (here or previously analysed) under few main categories, that we found to nicely correlate with the experimental phenotypes reported for several of the analysed mutants. Some of the structural analyses we present here provide a rationale for previously experimentally observed phenotypes. Furthermore, our comprehensive overview can be used as a reference frame for the interpretation, on a structural basis, of defective phenotypes of other aquaporin pathogenic mutants.
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MESH Headings
- Amino Acid Sequence
- Aquaporin 2/chemistry
- Aquaporin 2/genetics
- Aquaporin 2/metabolism
- Aquaporin 5/chemistry
- Aquaporin 5/genetics
- Aquaporin 5/metabolism
- Aquaporins/chemistry
- Aquaporins/genetics
- Aquaporins/metabolism
- Colorectal Neoplasms/genetics
- Colorectal Neoplasms/metabolism
- Colorectal Neoplasms/pathology
- Databases, Protein
- Diabetes Insipidus, Nephrogenic/genetics
- Diabetes Insipidus, Nephrogenic/metabolism
- Diabetes Insipidus, Nephrogenic/pathology
- Gene Expression
- Genetic Predisposition to Disease
- Genotype
- Humans
- Keratoderma, Palmoplantar/genetics
- Keratoderma, Palmoplantar/metabolism
- Keratoderma, Palmoplantar/pathology
- Models, Molecular
- Mutation
- Phenotype
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Protein Multimerization
- Sequence Alignment
- Sequence Homology, Amino Acid
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Affiliation(s)
- Luisa Calvanese
- CIRPeB, University of Naples Federico II, Napoli I-80134, Italy.
| | - Gabriella D'Auria
- CIRPeB, University of Naples Federico II, Napoli I-80134, Italy.
- Department of Pharmacy, University of Naples Federico II, Napoli I-80134, Italy.
- Institute of Biostructures and Bioimaging, CNR, Napoli I-80134, Italy.
| | - Anna Vangone
- Bijvoet Center for Biomolecular Research, Faculty of Science, Department of Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Lucia Falcigno
- CIRPeB, University of Naples Federico II, Napoli I-80134, Italy.
- Department of Pharmacy, University of Naples Federico II, Napoli I-80134, Italy.
- Institute of Biostructures and Bioimaging, CNR, Napoli I-80134, Italy.
| | - Romina Oliva
- Department of Sciences and Technologies, University Parthenope of Naples, Napoli I-80143, Italy.
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16
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Ando F, Uchida S. Activation of AQP2 water channels without vasopressin: therapeutic strategies for congenital nephrogenic diabetes insipidus. Clin Exp Nephrol 2018; 22:501-507. [PMID: 29478202 PMCID: PMC5956045 DOI: 10.1007/s10157-018-1544-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 01/20/2018] [Indexed: 02/06/2023]
Abstract
Congenital nephrogenic diabetes insipidus (NDI) is characterized by defective urine concentrating ability. Symptomatic polyuria is present from birth, even with normal release of the antidiuretic hormone vasopressin by the pituitary. Over the last two decades, the aquaporin-2 (AQP2) gene has been cloned and the molecular mechanisms of urine concentration have been gradually elucidated. Vasopressin binds to the vasopressin type II receptor (V2R) in the renal collecting ducts and then activates AQP2 phosphorylation and trafficking to increase water reabsorption from urine. Most cases of congenital NDI are caused by loss-of-function mutations to V2R, resulting in unresponsiveness to vasopressin. In this article, we provide an overview of novel therapeutic molecules of congenital NDI that can activate AQP2 by bypassing defective V2R signaling with a particular focus on the activators of the calcium and cAMP signaling pathways.
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Affiliation(s)
- Fumiaki Ando
- Department of Nephrology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Shinichi Uchida
- Department of Nephrology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
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17
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Kovaleva NV. An overlooked phenomenon: Female-biased sex ratio among carriers of Robertsonian translocations detected in consecutive newborn studies. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417120067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Milano S, Carmosino M, Gerbino A, Svelto M, Procino G. Hereditary Nephrogenic Diabetes Insipidus: Pathophysiology and Possible Treatment. An Update. Int J Mol Sci 2017; 18:ijms18112385. [PMID: 29125546 PMCID: PMC5713354 DOI: 10.3390/ijms18112385] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 12/17/2022] Open
Abstract
Under physiological conditions, excessive loss of water through the urine is prevented by the release of the antidiuretic hormone arginine-vasopressin (AVP) from the posterior pituitary. In the kidney, AVP elicits a number of cellular responses, which converge on increasing the osmotic reabsorption of water in the collecting duct. One of the key events triggered by the binding of AVP to its type-2 receptor (AVPR2) is the exocytosis of the water channel aquaporin 2 (AQP2) at the apical membrane the principal cells of the collecting duct. Mutations of either AVPR2 or AQP2 result in a genetic disease known as nephrogenic diabetes insipidus, which is characterized by the lack of responsiveness of the collecting duct to the antidiuretic action of AVP. The affected subject, being incapable of concentrating the urine, presents marked polyuria and compensatory polydipsia and is constantly at risk of severe dehydration. The molecular bases of the disease are fully uncovered, as well as the genetic or clinical tests for a prompt diagnosis of the disease in newborns. A real cure for nephrogenic diabetes insipidus (NDI) is still missing, and the main symptoms of the disease are handled with s continuous supply of water, a restrictive diet, and nonspecific drugs. Unfortunately, the current therapeutic options are limited and only partially beneficial. Further investigation in vitro or using the available animal models of the disease, combined with clinical trials, will eventually lead to the identification of one or more targeted strategies that will improve or replace the current conventional therapy and grant NDI patients a better quality of life. Here we provide an updated overview of the genetic defects causing NDI, the most recent strategies under investigation for rescuing the activity of mutated AVPR2 or AQP2, or for bypassing defective AVPR2 signaling and restoring AQP2 plasma membrane expression.
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Affiliation(s)
- Serena Milano
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Monica Carmosino
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy.
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
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19
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Abstract
Diabetes insipidus is a disease characterized by polyuria and polydipsia due to inadequate release of arginine vasopressin from the posterior pituitary gland (neurohypophyseal diabetes insipidus) or due to arginine vasopressin insensitivity by the renal distal tubule, leading to a deficiency in tubular water reabsorption (nephrogenic diabetes insipidus). This article reviews the genetics of diabetes insipidus in the context of its diagnosis, clinical presentation, and therapy.
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Affiliation(s)
- Marie Helene Schernthaner-Reiter
- Clinical Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Vienna 1090, Austria; Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 31 Center Drive, Bethesda, MD 20892, USA.
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 31 Center Drive, Bethesda, MD 20892, USA
| | - Anton Luger
- Clinical Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Vienna 1090, Austria
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20
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Abstract
Disruption of water and electrolyte balance is frequently encountered in clinical medicine. Regulating water metabolism is critically important. Diabetes insipidus (DI) presented with excessive water loss from the kidney is a major disorder of water metabolism. To understand the molecular and cellular mechanisms and pathophysiology of DI and rationales of clinical management of DI is important for both research and clinical practice. This chapter will first review various forms of DI focusing on central diabetes insipidus (CDI) and nephrogenic diabetes insipidus (NDI ) . This is followed by a discussion of regulatory mechanisms underlying CDI and NDI , with a focus on the regulatory axis of vasopressin, vasopressin receptor 2 (V2R ) and the water channel molecule, aquaporin 2 (AQP2 ). The clinical manifestation, diagnosis and management of various forms of DI will also be discussed with highlights of some of the latest therapeutic strategies that are developed from in vitro experiments and animal studies.
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Affiliation(s)
- H A Jenny Lu
- Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA, 02114, USA.
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21
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Functional Recovery of AQP2 Recessive Mutations Through Hetero-Oligomerization with Wild-Type Counterpart. Sci Rep 2016; 6:33298. [PMID: 27641679 PMCID: PMC5027563 DOI: 10.1038/srep33298] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/25/2016] [Indexed: 12/15/2022] Open
Abstract
Aquaporin-2 (AQP2) is a homotetrameric water channel responsible for the final water reuptake in the kidney. Mutations in the protein induce nephrogenic diabetes insipidus (NDI), which challenges the water balance by producing large urinary volumes. Although recessive AQP2 mutations are believed to generate non-functional and monomeric proteins, the literature identifies several mild mutations which suggest the existence of mixed wt/mut tetramers likely to carry function in heterozygotes. Using Xenopus oocytes, we tested this hypothesis and found that mild mutants (V24A, D150E) can associate with wt-AQP2 in mixed heteromers, providing clear functional gain in the process (62 ± 17% and 63 ± 17% increases, respectively), conversely to the strong monomeric R187C mutant which fails to associate with wt-AQP2. In kidney cells, both V24A and D150E display restored targeting while R187C remains in intracellular stores. Using a collection of mutations to expand recovery analyses, we demonstrate that inter-unit contacts are central to this recovery process. These results not only present the ground data for the functional recovery of recessive AQP2 mutants through heteromerization, which prompt to revisit the accepted NDI model, but more importantly describe a general recovery process that could impact on all multimeric systems where recessive mutations are found.
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22
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Bichet DG, Bockenhauer D. Genetic forms of nephrogenic diabetes insipidus (NDI): Vasopressin receptor defect (X-linked) and aquaporin defect (autosomal recessive and dominant). Best Pract Res Clin Endocrinol Metab 2016; 30:263-76. [PMID: 27156763 DOI: 10.1016/j.beem.2016.02.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Nephrogenic diabetes insipidus (NDI), which can be inherited or acquired, is characterized by an inability to concentrate urine despite normal or elevated plasma concentrations of the antidiuretic hormone, arginine vasopressin (AVP). Polyuria with hyposthenuria and polydipsia are the cardinal clinical manifestations of the disease. About 90% of patients with congenital NDI are males with X-linked NDI who have mutations in the vasopressin V2 receptor (AVPR2) gene encoding the vasopressin V2 receptor. In less than 10% of the families studied, congenital NDI has an autosomal recessive or autosomal dominant mode of inheritance with mutations in the aquaporin-2 (AQP2) gene. When studied in vitro, most AVPR2 and AQP2 mutations lead to proteins trapped in the endoplasmic reticulum and are unable to reach the plasma membrane. Prior knowledge of AVPR2 or AQP2 mutations in NDI families and perinatal mutation testing is of direct clinical value and can avert the physical and mental retardation associated with repeated episodes of dehydration.
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Affiliation(s)
- Daniel G Bichet
- Department of Medicine, Université de Montréal, Canada; Department of Molecular and Integrative Physiology, Université de Montréal, Canada; Hôpital du Sacré-Coeur de Montréal, 5400 Boul. Gouin Ouest, Montréal, QC, Canada H4J 1C5.
| | - Detlef Bockenhauer
- UCL Institute of Child Health, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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23
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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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24
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25
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Dollerup P, Thomsen TM, Nejsum LN, Færch M, Österbrand M, Gregersen N, Rittig S, Christensen JH, Corydon TJ. Partial nephrogenic diabetes insipidus caused by a novel AQP2 variation impairing trafficking of the aquaporin-2 water channel. BMC Nephrol 2015; 16:217. [PMID: 26714855 PMCID: PMC4696136 DOI: 10.1186/s12882-015-0213-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 12/21/2015] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Autosomal dominant inheritance of congenital nephrogenic diabetes insipidus (CNDI) is rare and usually caused by variations in the AQP2 gene. We have investigated the genetic and molecular background underlying symptoms of diabetes insipidus (DI) in a Swedish family with autosomal dominant inheritance of the condition. METHODS The proband and her father were subjected to water deprivation testing and direct DNA sequencing of the coding regions of the AQP2 and AVP genes. Madin-Darby canine kidney (MDCK) cells stably expressing AQP2 variant proteins were generated by lentiviral gene delivery. Localization of AQP2 variant proteins in the cells under stimulated and unstimulated conditions was analyzed by means of immunostaining and confocal laser scanning microscopy. Intracellular trafficking of AQP2 variant proteins was studied using transient expression of mutant dynamin2-K44A-GFP protein and AQP2 variant protein phosphorylation levels were assessed by Western blotting analysis. RESULTS Clinical and genetic data suggest that the proband and her father suffer from partial nephrogenic DI due to a variation (g.4807C > T) in the AQP2 gene. The variation results in substitution of arginine-254 to tryptophan (p.R254W) in AQP2. Analysis of MDCK cells stably expressing AQP2 variant proteins revealed disabled phosphorylation, impaired trafficking and intracellular accumulation of AQP2-R254W protein. Notably, blocking of the endocytic pathway demonstrated impairment of AQP2-R254W to reach the cell surface. CONCLUSIONS Partial CNDI in the Swedish family is caused by an AQP2 variation that seems to disable the encoded AQP2-R254W protein to reach the subapical vesicle population as well as impairing its phosphorylation at S256. The AQP2-R254W protein is thus unable to reach the plasma membrane to facilitate AVP mediated urine concentration.
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Affiliation(s)
- Pia Dollerup
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
| | - Troels Møller Thomsen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
| | - Lene N Nejsum
- Department of Molecular Biology and Genetics and iNANO, Aarhus University, Aarhus, Denmark.
| | - Mia Færch
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
| | - Martin Österbrand
- Department of Pediatrics, Queen Silvia Children's Hospital, Gothenburg, Sweden.
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - Søren Rittig
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
| | - Jane H Christensen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
| | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
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26
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Abstract
Congenital nephrogenic diabetes insipidus (NDI) is a conformation disease resulting from protein misfolding. Ninety percent of mutations result from the inactivating mutations of the arginine vasopressin receptor 2 (AVPR2) gene transmitted in an X-linked fashion, blocking the response to vasopressin, resulting in the inability to concentrate urine. Clinical features include polyuria, polydispsia, dehydration, and hypernatremia. They are generally more severely in affected males but present variably in females due to skewed inactivation of the X chromosome. We describe a case of a 40-year-old woman with a history of Type 2 diabetes mellitus, hyperlipidemia, and obesity, who presents with debilitating polyuria since the age of 5 with no clear diagnosis. Interestingly, her son was diagnosed with NDI. Genetic testing revealed that she was heterozygous for the Val88Met mutation in the AVPR2 gene while her son was hemizygous for the same. The patient has since been successfully treated with diuretics and a low solute diet. We highlight that although X-linked NDI patients are mostly males, it should be considered in symptomatic females to prevent delays in the diagnosis. Conformational diseases such as NDI are presently the subject of research using pharmacological chaperones to restore proper receptor membrane localization and function.
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Affiliation(s)
- Tanvi Rege
- Nephrology Division, Department of Medicine, Jacobi Medical Center, Albert Einstein College of Medicine , Bronx, NY , USA
| | - Srujana Polsani
- University Medical Center of Princeton at Plainsboro, Rutgers Robert Wood Johnson Medical School , Plainsboro, NJ , USA
| | - Belinda Jim
- Nephrology Division, Department of Medicine, Jacobi Medical Center, Albert Einstein College of Medicine , Bronx, NY , USA
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27
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Bockenhauer D, Bichet DG. Pathophysiology, diagnosis and management of nephrogenic diabetes insipidus. Nat Rev Nephrol 2015; 11:576-88. [PMID: 26077742 DOI: 10.1038/nrneph.2015.89] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Healthy kidneys maintain fluid and electrolyte homoeostasis by adjusting urine volume and composition according to physiological needs. The final urine composition is determined in the last tubular segment: the collecting duct. Water permeability in the collecting duct is regulated by arginine vasopressin (AVP). Secretion of AVP from the neurohypophysis is regulated by a complex signalling network that involves osmosensors, barosensors and volume sensors. AVP facilitates aquaporin (AQP)-mediated water reabsorption via activation of the vasopressin V2 receptor (AVPR2) in the collecting duct, thus enabling concentration of urine. In nephrogenic diabetes insipidus (NDI), inability of the kidneys to respond to AVP results in functional AQP deficiency. Consequently, affected patients have constant diuresis, resulting in large volumes of dilute urine. Primary forms of NDI result from mutations in the genes that encode the key proteins AVPR2 and AQP2, whereas secondary forms are associated with biochemical abnormalities, obstructive uropathy or the use of certain medications, particularly lithium. Treatment of the disease is informed by identification of the underlying cause. Here we review the clinical aspects and diagnosis of NDI, the various aetiologies, current treatment options and potential future developments.
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Affiliation(s)
- Detlef Bockenhauer
- University College London Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Daniel G Bichet
- Departments of Medicine and Molecular and Integrative Physiology, Université de Montréal Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Boulevard Gouin Ouest, Montréal, QC H4J 1C5 Canada
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28
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Abstract
Specific channels permit movement of selected ions through cellular membranes, and are of vital importance in a number of physiological processes, particularly in excitable tissues such as nerve and muscle, but also in endocrine organs and in epithelial biology. Disorders of channel proteins are termed channelopathies, and their importance is increasingly recognised within medicine. In the kidney, ion channels have critical roles enabling sodium and potassium reuptake or excretion along the nephron, in magnesium homeostasis, in the control of water reabsorption in the collecting duct, and in determining glomerular permeability. In this review, we assess the channelopathies encountered in each nephron segment, and see how their molecular and genetic characterisation in the past 20–30 years has furthered our understanding of normal kidney physiology and disease processes, aids correct diagnosis and promises future therapeutic opportunities.
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Affiliation(s)
- KW Loudon
- Department of Renal Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - AC Fry
- Department of Renal Medicine, Addenbrooke’s Hospital, Cambridge, UK
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29
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Dynamic regulation and dysregulation of the water channel aquaporin-2: a common cause of and promising therapeutic target for water balance disorders. Clin Exp Nephrol 2013; 18:558-70. [DOI: 10.1007/s10157-013-0878-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/24/2013] [Indexed: 12/11/2022]
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30
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Blaydon D, Lind L, Plagnol V, Linton K, Smith F, Wilson N, McLean W, Munro C, South A, Leigh I, O’Toole E, Lundström A, Kelsell D. Mutations in AQP5, encoding a water-channel protein, cause autosomal-dominant diffuse nonepidermolytic palmoplantar keratoderma. Am J Hum Genet 2013; 93:330-5. [PMID: 23830519 DOI: 10.1016/j.ajhg.2013.06.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/08/2013] [Accepted: 06/08/2013] [Indexed: 11/24/2022] Open
Abstract
Autosomal-dominant diffuse nonepidermolytic palmoplantar keratoderma is characterized by the adoption of a white, spongy appearance of affected areas upon exposure to water. After exome sequencing, missense mutations were identified in AQP5, encoding water-channel protein aquaporin-5 (AQP5). Protein-structure analysis indicates that these AQP5 variants have the potential to elicit an effect on normal channel regulation. Immunofluorescence data reveal the presence of AQP5 at the plasma membrane in the stratum granulosum of both normal and affected palmar epidermis, indicating that the altered AQP5 proteins are trafficked in the normal manner. We demonstrate here a role for AQP5 in the palmoplantar epidermis and propose that the altered AQP5 proteins retain the ability to form open channels in the cell membrane and conduct water.
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31
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Moeller HB, Rittig S, Fenton RA. Nephrogenic diabetes insipidus: essential insights into the molecular background and potential therapies for treatment. Endocr Rev 2013; 34:278-301. [PMID: 23360744 PMCID: PMC3610677 DOI: 10.1210/er.2012-1044] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The water channel aquaporin-2 (AQP2), expressed in the kidney collecting ducts, plays a pivotal role in maintaining body water balance. The channel is regulated by the peptide hormone arginine vasopressin (AVP), which exerts its effects through the type 2 vasopressin receptor (AVPR2). Disrupted function or regulation of AQP2 or the AVPR2 results in nephrogenic diabetes insipidus (NDI), a common clinical condition of renal origin characterized by polydipsia and polyuria. Over several years, major research efforts have advanced our understanding of NDI at the genetic, cellular, molecular, and biological levels. NDI is commonly characterized as hereditary (congenital) NDI, arising from genetic mutations in the AVPR2 or AQP2; or acquired NDI, due to for exmple medical treatment or electrolyte disturbances. In this article, we provide a comprehensive overview of the genetic, cell biological, and pathophysiological causes of NDI, with emphasis on the congenital forms and the acquired forms arising from lithium and other drug therapies, acute and chronic renal failure, and disturbed levels of calcium and potassium. Additionally, we provide an overview of the exciting new treatment strategies that have been recently proposed for alleviating the symptoms of some forms of the disease and for bypassing G protein-coupled receptor signaling.
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Affiliation(s)
- Hanne B Moeller
- Department of Biomedicine, Aarhus University, and Department of Pediatrics, Aarhus University Hospital, Wilhelm Meyers Alle 3, Building 1234, Aarhus 8000, Denmark.
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32
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Shida Y, Matsuoka H, Chiga M, Uchida S, Sasaki S, Sugihara S. Characterization of AQP-2 gene mutation (R254Q) in a family with dominant nephrogenic DI. Pediatr Int 2013; 55:105-7. [PMID: 23409988 DOI: 10.1111/j.1442-200x.2012.03614.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We identified the AQP-2 gene mutation (R254Q) in a family with dominant NDI. The patient studied here has NDI with partial response to the anti-diuretic effect of AVP and dDAVP. Hereditary NDI seems to have the uniform clinical manifestations, but this might only reflect the information on screened patients with clear clinical presentations. It may be that a milder form of NDI has been overlooked due to a lack of genetic identification. Gene mutation analysis should be considered even in patients with mild NDI symptoms. Fortunately, both V2R and AQP2 genes are small and can be easily analyzed.
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Affiliation(s)
- Yoko Shida
- Department of Pediatrics, Tokyo Women's Medical University Medical Center East Department of Homeostasis Medicine and Nephrology, Tokyo Medical and Dental University, Tokyo, Japan
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33
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Congenital nephrogenic diabetes insipidus: the current state of affairs. Pediatr Nephrol 2012; 27:2183-204. [PMID: 22427315 DOI: 10.1007/s00467-012-2118-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/14/2012] [Accepted: 01/17/2012] [Indexed: 01/02/2023]
Abstract
The anti-diuretic hormone arginine vasopressin (AVP) is released from the pituitary upon hypovolemia or hypernatremia, and regulates water reabsorption in the renal collecting duct principal cells. Binding of AVP to the arginine vasopressin receptor type 2 (AVPR2) in the basolateral membrane leads to translocation of aquaporin 2 (AQP2) water channels to the apical membrane of the collecting duct principal cells, inducing water permeability of the membrane. This results in water reabsorption from the pro-urine into the medullary interstitium following an osmotic gradient. Congenital nephrogenic diabetes insipidus (NDI) is a disorder associated with mutations in either the AVPR2 or AQP2 gene, causing the inability of patients to concentrate their pro-urine, which leads to a high risk of dehydration. This review focuses on the current knowledge regarding the cell biological aspects of congenital X-linked, autosomal-recessive and autosomal-dominant NDI while specifically addressing the latest developments in the field. Based on deepened mechanistic understanding, new therapeutic strategies are currently being explored, which we also discuss here.
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Sasaki S, Chiga M, Kikuchi E, Rai T, Uchida S. Hereditary nephrogenic diabetes insipidus in Japanese patients: analysis of 78 families and report of 22 new mutations in AVPR2 and AQP2. Clin Exp Nephrol 2012; 17:338-44. [PMID: 23150186 DOI: 10.1007/s10157-012-0726-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 10/28/2012] [Indexed: 12/22/2022]
Abstract
BACKGROUND Familial form of nephrogenic diabetes insipidus (NDI) is a rare hereditary disease caused by arginine vasopressin type 2 receptor (AVPR2) or water channel aquaporin 2 (AQP2) gene mutations. It is speculated that 90% of NDI families carry disease-causing mutations in AVPR2 and 10% carry the mutations in AQP2; however, these percentages have not been supported by actual data. It is also unknown whether these percentages vary in different ethnic groups. METHODS Gene mutation analyses were performed for 78 Japanese NDI families. All exons and intron-exon boundaries of the AVPR2 and AQP2 genes were directly sequenced. RESULTS A total of 62 families (79%) carried disease-causing mutations in AVPR2, while nine families (12%) carried mutations in AQP2. We identified 22 novel putatively disease-causing mutations (19 in AVPR2 and 3 in AQP2). Regarding AVPR2, 52 disease-causing mutations were identified. Among them, missense mutations were most common (54%), followed by deletion mutations. In the 64 women who had monoallelic disease-causing AVPR2 mutations, 16 (25%) had NDI symptoms, including 4 complete NDI subjects. Regarding AQP2, 9 disease-causing mutations were identified in nine families. Two missense mutations and one deletion mutation showed a recessive inheritance, while one missense mutation and five small deletion mutations in the C-terminus of AQP2 showed a dominant inheritance. CONCLUSIONS Most Japanese NDI families carry disease-causing mutations in AVPR2 and 12% carry mutations in AQP2. A total of 22 novel putatively disease-causing mutations were identified. The relatively high occurrence of symptomatic carriers of AVPR2 mutations needs attention.
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Affiliation(s)
- Sei Sasaki
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
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Sasaki S. Aquaporin 2: From its discovery to molecular structure and medical implications. Mol Aspects Med 2012; 33:535-46. [DOI: 10.1016/j.mam.2012.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 03/12/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
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Tamma G, Procino G, Svelto M, Valenti G. Cell culture models and animal models for studying the patho-physiological role of renal aquaporins. Cell Mol Life Sci 2012; 69:1931-46. [PMID: 22189994 PMCID: PMC11114724 DOI: 10.1007/s00018-011-0903-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 11/07/2011] [Accepted: 11/29/2011] [Indexed: 12/29/2022]
Abstract
Aquaporins (AQPs) are key players regulating urinary-concentrating ability. To date, eight aquaporins have been characterized and localized along the nephron, namely, AQP1 located in the proximal tubule, thin descending limb of Henle, and vasa recta; AQP2, AQP3 and AQP4 in collecting duct principal cells; AQP5 in intercalated cell type B; AQP6 in intercalated cells type A in the papilla; AQP7, AQP8 and AQP11 in the proximal tubule. AQP2, whose expression and cellular distribution is dependent on vasopressin stimulation, is involved in hereditary and acquired diseases affecting urine-concentrating mechanisms. Due to the lack of selective aquaporin inhibitors, the patho-physiological role of renal aquaporins has not yet been completely clarified, and despite extensive studies, several questions remain unanswered. Until the recent and large-scale development of genetic manipulation technology, which has led to the generation of transgenic mice models, our knowledge on renal aquaporin regulation was mainly based on in vitro studies with suitable renal cell models. Transgenic and knockout technology approaches are providing pivotal information on the role of aquaporins in health and disease. The main goal of this review is to update and summarize what we can learn from cell and animal models that will shed more light on our understanding of aquaporin-dependent renal water regulation.
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Affiliation(s)
- G Tamma
- Department of Biosciences, Biotechnologies and Pharmacological Sciences, University of Bari, Italy
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Bichet DG, El Tarazi A, Matar J, Lussier Y, Arthus MF, Lonergan M, Bockenhauer D, Bissonnette P. Aquaporin-2: new mutations responsible for autosomal-recessive nephrogenic diabetes insipidus-update and epidemiology. Clin Kidney J 2012; 5:195-202. [PMID: 26069764 PMCID: PMC4400507 DOI: 10.1093/ckj/sfs029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 02/22/2012] [Indexed: 11/14/2022] Open
Abstract
It is clinically useful to distinguish between two types of hereditary nephrogenic diabetes insipidus (NDI): a ‘pure’ type characterized by loss of water only and a complex type characterized by loss of water and ions. Patients with congenital NDI bearing mutations in the vasopressin 2 receptor gene, AVPR2, or in the aquaporin-2 gene, AQP2, have a pure NDI phenotype with loss of water but normal conservation of sodium, potassium, chloride and calcium. Patients with hereditary hypokalemic salt-losing tubulopathies have a complex phenotype with loss of water and ions. They have polyhydramnios, hypercalciuria and hypo- or isosthenuria and were found to bear KCNJ1 (ROMK) and SLC12A1 (NKCC2) mutations. Patients with polyhydramnios, profound polyuria, hyponatremia, hypochloremia, metabolic alkalosis and sensorineural deafness were found to bear BSND mutations. These clinical phenotypes demonstrate the critical importance of the proteins ROMK, NKCC2 and Barttin to transfer NaCl in the medullary interstitium and thereby to generate, together with urea, a hypertonic milieu. This editorial describes two new developments: (i) the genomic information provided by the sequencing of the AQP2 gene is key to the routine care of these patients, and, as in other genetic diseases, reduces health costs and provides psychological benefits to patients and families and (ii) the expression of AQP2 mutants in Xenopus oocytes and in polarized renal tubular cells recapitulates the clinical phenotypes and reveals a continuum from severe loss of function with urinary osmolalities <150 mOsm/kg H2O to milder defects with urine osmolalities >200 mOsm/kg H2O.
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Affiliation(s)
- Daniel G Bichet
- Groupe d'Étude des Protéines Membranaires (GÉPROM), Département de Physiologie, Université de Montréal, Montréal, Québec, Canada ; Centre de Recherche, Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada
| | - Abdulah El Tarazi
- Groupe d'Étude des Protéines Membranaires (GÉPROM), Département de Physiologie, Université de Montréal, Montréal, Québec, Canada
| | - Jessica Matar
- Groupe d'Étude des Protéines Membranaires (GÉPROM), Département de Physiologie, Université de Montréal, Montréal, Québec, Canada
| | - Yoann Lussier
- Groupe d'Étude des Protéines Membranaires (GÉPROM), Département de Physiologie, Université de Montréal, Montréal, Québec, Canada
| | | | - Michèle Lonergan
- Centre de Recherche, Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada
| | - Detlef Bockenhauer
- Institute of Child Health, University College London, Great Ormond Street Hospital for Children, NHS Trust, London, UK
| | - Pierre Bissonnette
- Groupe d'Étude des Protéines Membranaires (GÉPROM), Département de Physiologie, Université de Montréal, Montréal, Québec, Canada
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Noda Y. [Aquaporin complex regulating urine concentration]. Nihon Yakurigaku Zasshi 2012; 139:66-9. [PMID: 22322930 DOI: 10.1254/fpj.139.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Abstract
Targeted positioning of the water channel AQP2 (aquaporin-2) strictly regulates body water homoeostasis. Trafficking of AQP2 to the apical membrane is critical for the reabsorption of water in renal collecting ducts. In addition to the cAMP-mediated effect of vasopressin on AQP2 trafficking to the apical membrane, other signalling cascades can also induce this sorting. Recently, AQP2-binding proteins which could regulate this trafficking have been discovered; SPA-1 (signal-induced proliferation-associated gene-1), a GAP (GTPase-activating protein) for Rap1, and the cytoskeletal protein actin. This review summarizes recent advances related to the trafficking mechanisms of AQP2.
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Affiliation(s)
- Yumi Noda
- Department of Nephrology, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
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Abstract
Over the past two decades, the genetic and molecular basis of familial forms of diabetes insipidus has been elucidated. Diabetes insipidus is a clinical syndrome characterized by the excretion of abnormally large volumes of diluted urine (polyuria) and increased fluid intake (polydipsia). The most common type of diabetes insipidus is caused by lack of the antidiuretic hormone arginine vasopressin (vasopressin), which is produced in the hypothalamus and secreted by the neurohypophysis. This type of diabetes insipidus is referred to here as neurohypophyseal diabetes insipidus. The syndrome can also result from resistance to the antidiuretic effects of vasopressin on the kidney, either at the level of the vasopressin 2 receptor or the aquaporin 2 water channel (which mediates the re-absorption of water from urine), and is referred to as renal or nephrogenic diabetes insipidus. Differentiation between these two types of diabetes insipidus and primary polydipsia can be difficult owing to the existence of partial as well as complete forms of vasopressin deficiency or resistance. Seven different familial forms of diabetes insipidus are known to exist. The clinical presentation, genetic basis and cellular mechanisms responsible for them vary considerably. This information has led to improved methods of differential diagnosis and could provide the basis of new forms of therapy.
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Affiliation(s)
- Muriel Babey
- Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Tarry 15, 303 East Chicago Avenue, Chicago, IL 60611, USA
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Edemir B, Pavenstädt H, Schlatter E, Weide T. Mechanisms of cell polarity and aquaporin sorting in the nephron. Pflugers Arch 2011; 461:607-21. [PMID: 21327781 DOI: 10.1007/s00424-011-0928-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 01/14/2011] [Accepted: 01/16/2011] [Indexed: 01/02/2023]
Abstract
The kidneys participate in whole-body homeostasis, regulating acid-base balance, electrolyte concentrations, extracellular fluid volume, and regulation of blood pressure. Many of the kidney's functions are accomplished by relatively simple mechanisms of filtration, reabsorption, and secretion, which take place in the nephron. The kidneys generate 140-180 l of primary urine per day, while reabsorbing a large percentage, allowing for only the excretion of approximately 2 l of urine. Within the nephron, the majority of the filtered water and solutes are reabsorbed. This is mainly facilitated by specialized transporters and channels which are localized at different segments of the nephron and asymmetrically localized within the polarized epithelial cells. The asymmetric localization of these transporters and channels is essential for the physiological tasks of the renal tissues. One family of these proteins are the water-permeable aquaporins which are selectively expressed in cells along the nephron and localized at different compartments. Here, we discuss potential molecular links between mechanisms involved in the establishment of cell polarity and the members of the aquaporin family. In the first part of this review, we will focus on aspects of apical cell polarity. In the second part, we will review the motifs identified so far that are involved in aquaporin sorting and point out potential molecular links.
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Affiliation(s)
- Bayram Edemir
- Medizinische Klinik und Poliklinik D, Experimentelle und Molekulare Nephrologie, Universität Münster, Germany.
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Leduc-Nadeau A, Lussier Y, Arthus MF, Lonergan M, Martinez-Aguayo A, Riveira-Munoz E, Devuyst O, Bissonnette P, Bichet DG. New autosomal recessive mutations in aquaporin-2 causing nephrogenic diabetes insipidus through deficient targeting display normal expression in Xenopus oocytes. J Physiol 2010; 588:2205-18. [PMID: 20403973 DOI: 10.1113/jphysiol.2010.187674] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Aquaporin-2 (AQP2), located at the luminal side of the collecting duct principal cells, is a water channel responsible for the final concentration of urine. Lack of function, often occurring through mistargeting of mutated proteins, induces nephrogenic diabetes insipidus (NDI), a condition characterized by large urinary volumes. In the present study, two new mutations (K228E and V24A) identified in NDI-affected individuals from distinct families along with the already reported R187C were analysed in comparison to the wild-type protein (AQP2-wt) using Xenopus laevis oocytes and a mouse collecting duct cell-line (mIMCD-3). Initial data in oocytes showed that all mutations were adequately expressed at reduced levels when compared to AQP2-wt. K228E and V24A were found to be properly targeted at the plasma membrane and exhibited adequate functionality similar to AQP2-wt, as opposed to R187C which was retained in internal stores and was thus inactive. In coexpression studies using oocytes, R187C impeded the functionality of all other AQP2 variants while combinations with K228E, V24A and AQP2-wt only showed additive functionalities. When expressed in mIMCD-3 cells, forskolin treatment efficiently promoted the targeting of AQP2-wt at the plasma membrane (>90%) while K228E only weakly responded to the same treatment (approximately 20%) and both V24A and R187C remained completely insensitive to the treatment. We concluded that both V24A and K228E are intrinsically functional water channels that lack a proper response to vasopressin, which leads to NDI as found in both compound mutations studied (K228E + R187C and V24A + R187C). The discrepancies in plasma membrane targeting response found in both expression systems stress the need to evaluate such data using mammalian cell systems.
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Affiliation(s)
- Alexandre Leduc-Nadeau
- Groupe d' Etude des Protéines Membranaires (GEPROM), département de Physiologie, Université de Montréal, Montréal, Québec, Canada
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Kamsteeg EJ, Stoffels M, Tamma G, Konings IB, Deen PM. Repulsion between Lys258 and upstream arginines explains the missorting of the AQP2 mutant p.Glu258Lys in nephrogenic diabetes insipidus. Hum Mutat 2009; 30:1387-96. [DOI: 10.1002/humu.21068] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Guyon C, Lussier Y, Bissonnette P, Leduc-Nadeau A, Lonergan M, Arthus MF, Perez RB, Tiulpakov A, Lapointe JY, Bichet DG. Characterization of D150E and G196D aquaporin-2 mutations responsible for nephrogenic diabetes insipidus: importance of a mild phenotype. Am J Physiol Renal Physiol 2009; 297:F489-98. [PMID: 19458121 DOI: 10.1152/ajprenal.90589.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Aquaporin-2 (AQP2) is a water channel responsible for the final water reabsorption in renal collecting ducts. Alterations in AQP2 function induce nephrogenic diabetes insipidus (NDI), a condition characterized by severe polyuria and polydipsia. Three patients affected with severe NDI, who were compound heterozygous for the AQP2 mutations D150E and G196D, are presented here along with a mildly affected D150E homozygous patient from another family. Using Xenopus oocytes as an expression system, these two mutations (G196D and D150E) were compared with the wild-type protein (AQP2-wt) for functional activity (water flux analysis), protein maturation, and plasma membrane targeting. AQP2-wt induces a major increase in water permeability (P(f) = 47.4 +/- 12.2 x 10(-4) cm/s) whereas D150E displays intermediate P(f) values (P(f) = 12.5 +/- 3.0 x 10(-4) cm/s) and G196D presents no specific water flux, similar to controls (P(f) = 2.1 +/- 0.8 x 10(-4) cm/s and 2.2 +/- 0.7 x 10(-4) cm/s, respectively). Western blot and immunocytochemical evaluations show protein targeting that parallels activity levels with AQP2-wt adequately targeted to the plasma membrane, partial targeting for D150E, and complete sequestration of G196D within intracellular compartments. When coinjecting AQP2-wt with mutants, no (AQP2-wt + D150E) or partial (AQP2-wt + G196D) reduction of water flux were observed compared with AQP2-wt alone, whereas complete loss of function was found when both mutants were coinjected. These results essentially recapitulate the clinical profiles of the family members, showing a typical dominant negative effect when G196D is coinjected with either AQP2-wt or D150E but not between AQP2-wt and D150E mutant.
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Affiliation(s)
- Cécile Guyon
- Groupe d'Etude des Protéines Membranaires, Département de Physiologie, Université de Montréal, Montréal, Québec, Canada
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van Balkom BWM, Boone M, Hendriks G, Kamsteeg EJ, Robben JH, Stronks HC, van der Voorde A, van Herp F, van der Sluijs P, Deen PMT. LIP5 interacts with aquaporin 2 and facilitates its lysosomal degradation. J Am Soc Nephrol 2009; 20:990-1001. [PMID: 19357255 DOI: 10.1681/asn.2008060648] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Vasopressin binding to the V2 receptor in renal principal cells leads to activation of protein kinase A, phosphorylation of aquaporin 2 (AQP2) at Ser256, and the translocation of AQP2 to the apical membrane, resulting in concentration of the urine. In contrast, phorbol ester-induced activation of protein kinase C pathway leads to ubiquitination of AQP2 at Lys270 and its internalization to multivesicular bodies, where it is targeted for lysosomal degradation or stored for recycling. Because little is known about the regulation of AQP2 trafficking, we used the carboxy-terminal tail of constitutively nonphosphorylated AQP2 (S256A) as a bait for interacting proteins in a yeast two-hybrid assay. We isolated lysosomal trafficking regulator-interacting protein 5 (LIP5) and found that LIP5 interacted with the proximal carboxy-terminal tail (L230-D243) of AQP2 in vitro but not with AQP3 or AQP4, which are also expressed in principal cells. Immunohistochemistry revealed that LIP5 co-localized with AQP2 in principal cells. LIP5 binding occurred independent of the state of Ser256 phosphorylation or Lys270 ubiquitination. LIP5 has been shown to facilitate degradation of the EGF receptor; here, LIP5 seemed to bind this receptor. Knockdown of LIP5 in mouse renal cells (mpkCCD) reduced the phorbol ester-induced degradation of AQP2 approximately two-fold. In summary, LIP5 binds cargo proteins and, considering the role of LIP5 in protein sorting to multivesicular bodies, plays a role in the degradation of AQP2, possibly by reducing the formation of late endosomes.
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Affiliation(s)
- Bas W M van Balkom
- Department of Physiology, Nijmegen Center of Molecular Sciences, 6500 HB Nijmegen, The Netherlands
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Nedvetsky PI, Tamma G, Beulshausen S, Valenti G, Rosenthal W, Klussmann E. Regulation of aquaporin-2 trafficking. Handb Exp Pharmacol 2009:133-157. [PMID: 19096775 DOI: 10.1007/978-3-540-79885-9_6] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Principal cells lining renal collecting ducts control the fine-tuning of body water homeostasis by regulating water reabsorption through the water channels aquaporin-2 (AQP2), aquaporin-3 (AQP3), and aquaporin-4 (AQP4). While the localization of AQP2 is subject to regulation by arginine-vasopressin (AVP), AQP3 and AQP4 are constitutively expressed in the basolateral plasma membrane. AVP adjusts the amount of AQP2 in the plasma membrane by triggering its redistribution from intracellular vesicles into the plasma membrane. This permits water entry into the cells and water exit through AQP3 and AQP4. The translocation of AQP2 is initiated by an increase in cAMP following V2R activation through AVP. The AVP-induced rise in cAMP activates protein kinase A (PKA), which in turn phosphorylates AQP2, and thereby triggers the redistribution of AQP2. Several proteins participating in the control of cAMP-dependent AQP2 trafficking have been identified; for example, A kinase anchoring proteins (AKAPs) tethering PKA to cellular compartments; phosphodiesterases (PDEs) regulating the local cAMP level; cytoskeletal components such as F-actin and microtubules; small GTPases of the Rho family controlling cytoskeletal dynamics; motor proteins transporting AQP2-bearing vesicles to and from the plasma membrane for exocytic insertion and endocytic retrieval; SNAREs inducing membrane fusions, hsc70, a chaperone, important for endocytic retrieval. In addition, cAMP-independent mechanisms of translocation mainly involving the F-actin cytoskeleton have been uncovered. Defects of AQP2 trafficking cause diseases such as nephrogenic diabetes insipidus (NDI), a disorder characterized by a massive loss of hypoosmotic urine.This review summarizes recent data elucidating molecular mechanisms underlying the trafficking of AQP2. In particular, we focus on proteins involved in the regulation of trafficking, and physiological and pathophysiological stimuli determining the cellular localization of AQP2. The identification of proteins and protein-protein interactions may lead to the development of drugs targeting AQP2 trafficking. Such drugs may be suitable for the treatment of diseases associated with dysregulation of body water homeostasis, including NDI or cardiovascular diseases (e.g., chronic heart failure) where the AVP level is elevated, inducing excessive water retention.
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Affiliation(s)
- Pavel I Nedvetsky
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Berlin, 13125, Germany
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Moon SS, Kim HJ, Choi YK, Seo HA, Jeon JH, Lee JE, Lee JY, Kwon TH, Kim JG, Kim BW, Lee IK. Novel mutation of aquaporin-2 gene in a patient with congenital nephrogenic diabetes insipidus. Endocr J 2009; 56:905-10. [PMID: 19461158 DOI: 10.1507/endocrj.k09e-078] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Congenital nephrogenic diabetes insipidus (CNDI) is a rare inherited disease, characterized by an inability of the kidney to concentrate urine in response to vasopressin. Three different inheritance patterns have been described, i.e., the X-linked recessive form associated with arginine vasopressin V2 receptor (AVPR2) gene mutations, the autosomal recessive and dominant forms of CNDI associated with mutations in the aquaporin-2 (AQP2) gene encoding the vasopressin-regulated water channel of the renal collecting duct. Our case is an 18-year-old male patient who complained of severe polyuria since his infancy. But his developmental and growth status were normal. He was diagnosed as CNDI by water deprivation test and genomic DNA sequencing, which revealed high plasma AVP levels but persistently low urine osmolalities to 6 h-water deprivation and the novel missense mutation S216F in exon4 of the AQP2 gene. Immunohistochemistry of renal biopsied tissue revealed that most of the AQP2 labeling was seen intracellularly in a dotted pattern in the collecting duct principal cells. Immunoblotting of urine samples revealed significantly decreased urinary excretion of AQP2 (approximately 7% of normal control). Here, we report a new case of CNDI associated with the novel missense mutation of the AQP2 gene.
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Affiliation(s)
- Seong-Su Moon
- Department of Endocrinology and Metabolism, Kyungpook National University Hospital, Daegu, Korea
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Affiliation(s)
- Tae-Hwan Kwon
- Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark
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Loonen AJM, Knoers NVAM, van Os CH, Deen PMT. Aquaporin 2 mutations in nephrogenic diabetes insipidus. Semin Nephrol 2008; 28:252-65. [PMID: 18519086 DOI: 10.1016/j.semnephrol.2008.03.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Water reabsorption in the renal collecting duct is regulated by the antidiuretic hormone vasopressin (AVP). When the vasopressin V2 receptor, present on the basolateral site of the renal principal cell, becomes activated by AVP, aquaporin-2 (AQP2) water channels will be inserted in the apical membrane, and in this fashion, water can be reabsorbed from the pro-urine into the interstitium. The essential role of the vasopressin V2 receptor and AQP2 in the maintenance of body water homeostasis became clear when it was shown that mutations in their genes cause nephrogenic diabetes insipidus, a disorder in which the kidney is unable to concentrate urine in response to AVP. This review describes the current knowledge on AQP2 mutations in nephrogenic diabetes insipidus.
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Affiliation(s)
- Anne J M Loonen
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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