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Mayayo-Vallverdú C, Gaitán-Peñas H, Armand-Ugon M, Muhaisen A, Prat E, Castellanos A, Elorza-Vidal X, de Heredia ML, Alonso-Gardón M, Pérez-Rius C, Vecino-Pérez M, Mallen A, Errasti-Murugarren E, Hueso M, Artuch R, Nunes V, Estévez R. Regulation of ClC-K/barttin by endocytosis influences distal convoluted tubule hyperplasia. J Physiol 2024; 602:4291-4307. [PMID: 39106251 DOI: 10.1113/jp286729] [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: 04/11/2024] [Accepted: 07/11/2024] [Indexed: 08/09/2024] Open
Abstract
ClC-K/barttin channels are involved in the transepithelial transport of chloride in the kidney and inner ear. Their physiological role is crucial in humans because mutations in CLCNKB or BSND, encoding ClC-Kb and barttin, cause Bartter's syndrome types III and IV, respectively. In vitro experiments have shown that an amino acid change in a proline-tyrosine motif in the C-terminus of barttin stimulates ClC-K currents. The molecular mechanism of this enhancement and whether this potentiation has any in vivo relevance remains unknown. We performed electrophysiological and biochemical experiments in Xenopus oocytes and kidney cells co-expressing ClC-K and barttin constructs. We demonstrated that barttin possesses a YxxØ motif and, when mutated, increases ClC-K plasma membrane stability, resulting in larger currents. To address the impact of mutating this motif in kidney physiology, we generated a knock-in mouse. Comparing wild-type (WT) and knock-in mice under a standard diet, we could not observe any difference in ClC-K and barttin protein levels or localization, either in urinary or plasma parameters. However, under a high-sodium low-potassium diet, known to induce hyperplasia of distal convoluted tubules, knock-in mice exhibit reduced hyperplasia compared to WT mice. In summary, our in vitro and in vivo studies demonstrate that the previously identified PY motif is indeed an endocytic YxxØ motif in which mutations cause a gain of function of the channel. KEY POINTS: It is revealed by mutagenesis and functional experiments that a previously identified proline-tyrosine motif regulating ClC-K plasma membrane levels is indeed an endocytic YxxØ motif. Biochemical characterization of mutants in the YxxØ motif in Xenopus oocytes and human embryonic kidney cells indicates that mutants showed increased plasma membrane levels as a result of an increased stability, resulting in higher function of ClC-K channels. Mutation of this motif does not affect barttin protein expression and subcellular localization in vivo. Knock-in mice with a mutation in this motif, under conditions of a high-sodium low-potassium diet, exhibit less hyperplasia in the distal convoluted tubule than wild-type animals, indicating a gain of function of the channel in vivo.
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Affiliation(s)
- Clara Mayayo-Vallverdú
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Héctor Gaitán-Peñas
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Mercedes Armand-Ugon
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Ashraf Muhaisen
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Esther Prat
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Aida Castellanos
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Xabier Elorza-Vidal
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Miguel López de Heredia
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Alonso-Gardón
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Carla Pérez-Rius
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Marta Vecino-Pérez
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Adrián Mallen
- Department of Nephrology, Hospital Universitart Bellvitge and Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Ekaitz Errasti-Murugarren
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Miguel Hueso
- Department of Nephrology, Hospital Universitart Bellvitge and Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Rafael Artuch
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
- Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Virginia Nunes
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Raúl Estévez
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
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Lin MH, Chen JC, Tian X, Lee CM, Yu IS, Lo YF, Uchida S, Huang CL, Chen BC, Cheng CJ. Impairment in renal medulla development underlies salt wasting in Clc-k2 channel deficiency. JCI Insight 2021; 6:e151039. [PMID: 34499620 PMCID: PMC8564913 DOI: 10.1172/jci.insight.151039] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 09/08/2021] [Indexed: 12/13/2022] Open
Abstract
The prevailing view is that the ClC-Ka chloride channel (mouse Clc-k1) functions in the thin ascending limb to control urine concentration, whereas the ClC-Kb channel (mouse Clc-k2) functions in the thick ascending limb (TAL) to control salt reabsorption. Mutations of ClC-Kb cause classic Bartter syndrome, characterized by renal salt wasting, with perinatal to adolescent onset. We studied the roles of Clc-k channels in perinatal mouse kidneys using constitutive or inducible kidney-specific gene ablation and 2D and advanced 3D imaging of optically cleared kidneys. We show that Clc-k1 and Clc-k2 were broadly expressed and colocalized in perinatal kidneys. Deletion of Clc-k1 and Clc-k2 revealed that both participated in NKCC2- and NCC-mediated NaCl reabsorption in neonatal kidneys. Embryonic deletion of Clc-k2 caused tubular injury and impaired renal medulla and TAL development. Inducible deletion of Clc-k2 beginning after medulla maturation produced mild salt wasting resulting from reduced NCC activity. Thus, both Clc-k1 and Clc-k2 contributed to salt reabsorption in TAL and distal convoluted tubule (DCT) in neonates, potentially explaining the less-severe phenotypes in classic Bartter syndrome. As opposed to the current understanding that salt wasting in adult patients with Bartter syndrome is due to Clc-k2 deficiency in adult TAL, our results suggest that it originates mainly from defects occurring in the medulla and TAL during development.
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Affiliation(s)
- Meng-Hsuan Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, and.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Jen-Chi Chen
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, and
| | - Xuejiao Tian
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan
| | - Chia-Ming Lee
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - I-Shing Yu
- Laboratory Animal Center, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Fen Lo
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, and
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Chou-Long Huang
- Division of Nephrology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Bi-Chang Chen
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan.,Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Chih-Jen Cheng
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, and.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Nephrology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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3
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Li LL, Ma SK, Peng W, Fang YG, Duo HR, Fu HY, Jia GX. Genetic diversity and population structure of Tibetan sheep breeds determined by whole genome resequencing. Trop Anim Health Prod 2021; 53:174. [PMID: 33611716 DOI: 10.1007/s11250-021-02605-6] [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: 10/18/2020] [Accepted: 02/08/2021] [Indexed: 12/01/2022]
Abstract
Tibetan sheep is one of primitive Chinese sheep breeds, which achieved the divergence about 2500 years ago in Qinghai plateau region. According to different geographic conditions, especially altitudes, Tibetan sheep evolved into different breeds. In this study, we performed whole genome resequencing of 5 representative Tibetan sheep breeds. Comparative genomic analysis showed that they can be divided into different clades with a close genetic relationship. However, some genes with common selective regions were enriched for hypoxic adaptability in different breeds living at higher altitude, including GHR, BMP15, and CPLANE1. Furthermore, breed-specific selective regions about physical characteristics, especially wool growth, were found in genes such as BSND, USP24, NCAPG, and LCORL. This study could contribute to our understanding about trait formation and offer a reference for breeding of Tibetan sheep.
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Affiliation(s)
- Lei-Lei Li
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Shi-Ke Ma
- Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, 810016, China
| | - Wei Peng
- Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, 810016, China
| | - You-Gui Fang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810001, China
| | - Hai-Rui Duo
- School of Geography Science, Qinghai Normal University, Xining, 810016, China
| | - Hong-Yun Fu
- Qinghai Headquarter of Animal Husbandry Extension Station, Xining, 810008, China
| | - Gong-Xue Jia
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810001, China.
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Murillo-de-Ozores AR, Chávez-Canales M, de los Heros P, Gamba G, Castañeda-Bueno M. Physiological Processes Modulated by the Chloride-Sensitive WNK-SPAK/OSR1 Kinase Signaling Pathway and the Cation-Coupled Chloride Cotransporters. Front Physiol 2020; 11:585907. [PMID: 33192599 PMCID: PMC7606576 DOI: 10.3389/fphys.2020.585907] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/29/2020] [Indexed: 12/15/2022] Open
Abstract
The role of Cl- as an intracellular signaling ion has been increasingly recognized in recent years. One of the currently best described roles of Cl- in signaling is the modulation of the With-No-Lysine (K) (WNK) - STE20-Proline Alanine rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1) - Cation-Coupled Cl- Cotransporters (CCCs) cascade. Binding of a Cl- anion to the active site of WNK kinases directly modulates their activity, promoting their inhibition. WNK activation due to Cl- release from the binding site leads to phosphorylation and activation of SPAK/OSR1, which in turn phosphorylate the CCCs. Phosphorylation by WNKs-SPAK/OSR1 of the Na+-driven CCCs (mediating ions influx) promote their activation, whereas that of the K+-driven CCCs (mediating ions efflux) promote their inhibition. This results in net Cl- influx and feedback inhibition of WNK kinases. A wide variety of alterations to this pathway have been recognized as the cause of several human diseases, with manifestations in different systems. The understanding of WNK kinases as Cl- sensitive proteins has allowed us to better understand the mechanistic details of regulatory processes involved in diverse physiological phenomena that are reviewed here. These include cell volume regulation, potassium sensing and intracellular signaling in the renal distal convoluted tubule, and regulation of the neuronal response to the neurotransmitter GABA.
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Affiliation(s)
- Adrián Rafael Murillo-de-Ozores
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
- Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Chávez-Canales
- Unidad de Investigación UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Paola de los Heros
- Unidad de Investigación UNAM-INC, Research Division, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Sahbani D, Strumbo B, Tedeschi S, Conte E, Camerino GM, Benetti E, Montini G, Aceto G, Procino G, Imbrici P, Liantonio A. Functional Study of Novel Bartter's Syndrome Mutations in ClC-Kb and Rescue by the Accessory Subunit Barttin Toward Personalized Medicine. Front Pharmacol 2020; 11:327. [PMID: 32256370 PMCID: PMC7092721 DOI: 10.3389/fphar.2020.00327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 03/05/2020] [Indexed: 12/12/2022] Open
Abstract
Type III and IV Bartter syndromes (BS) are rare kidney tubulopathies caused by loss-of-function mutations in the CLCNKB and BSND genes coding respectively for the ClC-Kb chloride channels and accessory subunit barttin. ClC-K channels are expressed in the Henle's loop, distal convoluted tubule, and cortical collecting ducts of the kidney and contribute to chloride absorption and urine concentration. In our Italian cohort, we identified two new mutations in CLCNKB, G167V and G289R, in children affected by BS and previously reported genetic variants, A242E, a chimeric gene and the deletion of the whole CLCNKB. All the patients had hypokalemia and metabolic alkalosis, increased serum renin and aldosterone levels and were treated with a symptomatic therapy. In order to define the molecular mechanisms responsible for BS, we co-expressed ClC-Kb wild type and channels with point mutations with barttin in HEK 293 cells and characterized chloride currents through the patch-clamp technique. In addition, we attempted to revert the functional defect caused by BS mutations through barttin overexpression. G167V and A242E channels showed a drastic current reduction compared to wild type, likely suggesting compromised expression of mutant channels at the plasma membrane. Conversely, G289R channel was similar to wild type raising the doubt that an additional mutation in another gene or other mechanisms could account for the clinical phenotype. Interestingly, increasing ClC-K/barttin ratio augmented G167V and A242E mutants' chloride current amplitudes towards wild type levels. These results confirm a genotype-phenotype correlation in BS and represent a preliminary proof of concept that molecules functioning as molecular chaperones can restore channel function in expression-defective ClC-Kb mutants.
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Affiliation(s)
- Dalila Sahbani
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Bice Strumbo
- Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Silvana Tedeschi
- Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Elena Conte
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | | | - Elisa Benetti
- Nephrology, Dialysis and Transplant Unit, Department of Women's and Children's Health, University-Hospital of Padova, Padova, Italy
| | - Giovanni Montini
- Pediatric Nephrology, Dialysis, and Transplant Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | | | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Antonella Liantonio
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
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Gorinski N, Wojciechowski D, Guseva D, Abdel Galil D, Mueller FE, Wirth A, Thiemann S, Zeug A, Schmidt S, Zareba-Kozioł M, Wlodarczyk J, Skryabin BV, Glage S, Fischer M, Al-Samir S, Kerkenberg N, Hohoff C, Zhang W, Endeward V, Ponimaskin E. DHHC7-mediated palmitoylation of the accessory protein barttin critically regulates the functions of ClC-K chloride channels. J Biol Chem 2020; 295:5970-5983. [PMID: 32184353 DOI: 10.1074/jbc.ra119.011049] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 03/13/2020] [Indexed: 12/21/2022] Open
Abstract
Barttin is the accessory subunit of the human ClC-K chloride channels, which are expressed in both the kidney and inner ear. Barttin promotes trafficking of the complex it forms with ClC-K to the plasma membrane and is involved in activating this channel. Barttin undergoes post-translational palmitoylation that is essential for its functions, but the enzyme(s) catalyzing this post-translational modification is unknown. Here, we identified zinc finger DHHC-type containing 7 (DHHC7) protein as an important barttin palmitoyl acyltransferase, whose depletion affected barttin palmitoylation and ClC-K-barttin channel activation. We investigated the functional role of barttin palmitoylation in vivo in Zdhhc7 -/- mice. Although palmitoylation of barttin in kidneys of Zdhhc7 -/- animals was significantly decreased, it did not pathologically alter kidney structure and functions under physiological conditions. However, when Zdhhc7 -/- mice were fed a low-salt diet, they developed hyponatremia and mild metabolic alkalosis, symptoms characteristic of human Bartter syndrome (BS) type IV. Of note, we also observed decreased palmitoylation of the disease-causing R8L barttin variant associated with human BS type IV. Our results indicate that dysregulated DHHC7-mediated barttin palmitoylation appears to play an important role in chloride channel dysfunction in certain BS variants, suggesting that targeting DHHC7 activity may offer a potential therapeutic strategy for reducing hypertension.
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Affiliation(s)
- Nataliya Gorinski
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | | | - Daria Guseva
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Dalia Abdel Galil
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Franziska E Mueller
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Alexander Wirth
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Stefan Thiemann
- Institute for Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Andre Zeug
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Silke Schmidt
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Monika Zareba-Kozioł
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Jakub Wlodarczyk
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Boris V Skryabin
- Department of Medicine, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Münster, 48149 Münster, Germany
| | - Silke Glage
- Institute for Laboratory Animal Science, Hannover Medical School, 30625 Hannover, Germany
| | - Martin Fischer
- Institute for Neurophysiology, Hannover Medical School, 30625 Hannover, Germany
| | - Samer Al-Samir
- Institute of Vegetative Physiology, Hannover Medical School, 30625 Hannover, Germany
| | - Nicole Kerkenberg
- Department of Psychiatry and Psychotherapy, Laboratory for Molecular Psychiatry, University of Münster, 48149 Münster, Germany; Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, 48149 Münster, Germany
| | - Christa Hohoff
- Department of Psychiatry and Psychotherapy, Laboratory for Molecular Psychiatry, University of Münster, 48149 Münster, Germany
| | - Weiqi Zhang
- Department of Psychiatry and Psychotherapy, Laboratory for Molecular Psychiatry, University of Münster, 48149 Münster, Germany; Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, 48149 Münster, Germany
| | - Volker Endeward
- Institute of Vegetative Physiology, Hannover Medical School, 30625 Hannover, Germany
| | - Evgeni Ponimaskin
- Department of Cellular Neurophysiology, Hannover Medical School, 30625 Hannover, Germany.
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7
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Bignon Y, Sakhi I, Bitam S, Bakouh N, Keck M, Frachon N, Paulais M, Planelles G, Teulon J, Andrini O. Analysis of CLCNKB mutations at dimer-interface, calcium-binding site, and pore reveals a variety of functional alterations in ClC-Kb channel leading to Bartter syndrome. Hum Mutat 2019; 41:774-785. [PMID: 31803959 DOI: 10.1002/humu.23962] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 11/14/2019] [Accepted: 11/29/2019] [Indexed: 12/12/2022]
Abstract
Pathological missense mutations in CLCNKB gene give a wide spectrum of clinical phenotypes in Bartter syndrome type III patients. Molecular analysis of the mutated ClC-Kb channels can be helpful to classify the mutations according to their functional alteration. We investigated the functional consequences of nine mutations in the CLCNKB gene causing Bartter syndrome. We first established that all tested mutations lead to decreased ClC-Kb currents. Combining electrophysiological and biochemical methods in Xenopus laevis oocytes and in MDCKII cells, we identified three classes of mutations. One class is characterized by altered channel trafficking. p.A210V, p.P216L, p.G424R, and p.G437R are totally or partially retained in the endoplasmic reticulum. p.S218N is characterized by reduced channel insertion at the plasma membrane and altered pH-sensitivity; thus, it falls in the second class of mutations. Finally, we found a novel class of functionally inactivated mutants normally present at the plasma membrane. Indeed, we found that p.A204T alters the pH-sensitivity, p.A254V abolishes the calcium-sensitivity. p.G219C and p.G465R are probably partially inactive at the plasma membrane. In conclusion, most pathogenic mutants accumulate partly or totally in intracellular compartments, but some mutants are normally present at the membrane surface and simultaneously show a large range of altered channel gating properties.
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Affiliation(s)
- Yohan Bignon
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Imene Sakhi
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Sara Bitam
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Naziha Bakouh
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Mathilde Keck
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | | | - Marc Paulais
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Gabrielle Planelles
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Jacques Teulon
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Olga Andrini
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, Lyon, France
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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9
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Matsuura Y, Nomura N, Shoda W, Mori T, Isobe K, Susa K, Ando F, Sohara E, Rai T, Uchida S. Tacrolimus ameliorates the phenotypes of type 4 Bartter syndrome model mice through activation of sodium-potassium-2 chloride cotransporter and sodium-chloride cotransporter. Biochem Biophys Res Commun 2019; 517:364-368. [PMID: 31362893 DOI: 10.1016/j.bbrc.2019.07.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 07/22/2019] [Indexed: 11/18/2022]
Abstract
Type 4 Bartter syndrome (BS) is caused by genetic mutations in barttin, which is coded for by BSND. Barttin serves as the β-subunit of the ClC-K chloride (Cl-) channel, which is widely expressed in distal nephrons. Type 4 BS is characterized by severely impaired reabsorption of salt, which may cause polyuria, hypokalemia, and metabolic alkalosis. Calcineurin inhibitors reportedly induce renal salt retention and hyperkalemia by enhancing the phosphorylation of the sodium (Na+)-potassium (K+)-2Cl- cotransporter (NKCC2) and Na+-Cl- cotransporter (NCC). In addition, we have previously reported that tacrolimus, a calcineurin inhibitor, increases the levels of phosphorylated NCC. In this study, we administered tacrolimus to barttin hypomorphic (Bsndneo/neo) mice, a murine model of type 4 BS that exhibits polyuria, hypokalemia, and metabolic alkalosis. Administration of tacrolimus increased the serum K+ level and suppressed urinary K+ excretion. Furthermore, after treatment with tacrolimus, Bsndneo/neo mice increased levels of phosphorylated NCC and NKCC2. We conclude that tacrolimus partially improves clinical phenotypes of Bsndneo/neo mice, and that calcineurin inhibitors might be effective for treating type 4 BS.
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Affiliation(s)
- Yoshiaki Matsuura
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Naohiro Nomura
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan.
| | - Wakana Shoda
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Kiyoshi Isobe
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Koichiro Susa
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Fumiaki Ando
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Tatemitsu Rai
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
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10
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Pérez-Rius C, Castellanos A, Gaitán-Peñas H, Navarro A, Artuch R, Barrallo-Gimeno A, Estévez R. Role of zebrafish ClC-K/barttin channels in apical kidney chloride reabsorption. J Physiol 2019; 597:3969-3983. [PMID: 31177533 DOI: 10.1113/jp278069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/29/2019] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS We have characterized the zebrafish clc-k and barttin proteins, demonstrating that they form a protein complex mediating chloride flux in a similar manner to their mammalian counterparts. As in mammals, in zebrafish, clc-k and barttin are basically expressed in the kidney. Contrary to what is found in mammals, in zebrafish both proteins show an apical localization in the kidney. We have generated the first knockout in zebrafish of a CLC protein. Lack of clc-k in zebrafish resulted in embryonic lethality, possibly caused by a reduction in total chloride content. As a consequence, there is an up-regulation of other chloride channels and other regulatory mechanisms such as renin or the uro-guanylin receptor in the kidney. barttin is mislocalized in vivo when clc-k is not present, indicating that there is a mutual dependence of the protein expression and localization between barttin and clc-k proteins. ABSTRACT ClC-K/barttin channels are very important for salt transport in the kidney. This function can be clearly seen since mutations in CLCNKB or BSND cause Bartter's syndrome types III and IV, respectively. Working with the freshwater teleost zebrafish, we characterized the genes homologous to the mammalian chloride channel ClC-K and its obligate subunit barttin and we obtained and studied clc-k knockout zebrafish. The zebrafish clc-k/barttin proteins are very similar to their mammalian counterparts, and both proteins are necessary to mediate chloride currents. Localization studies indicated that both proteins are exclusively expressed in the apical membranes of zebrafish kidney tubules. Knockout of clc-k resulted in embryonic lethality. These animals showed barttin mislocalization and a reduction in whole-body chloride concentration, as well as up-regulation of the expression of other chloride channels and renin, and an increase in the kidney expression of the uroguanylin receptor. Our results indicate that apical kidney chloride reabsorption through clc-k/barttin channels is crucial for chloride homeostasis in zebrafish as it is in humans. The zebrafish model could be used as a new in vivo system to study ClC-K function.
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Affiliation(s)
- Carla Pérez-Rius
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Aida Castellanos
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Almudena Navarro
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain.,Clinical Biochemistry Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Esplugues de Llobregat, Spain
| | - Alejandro Barrallo-Gimeno
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
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11
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Haworth AS, Brackenbury WJ. Emerging roles for multifunctional ion channel auxiliary subunits in cancer. Cell Calcium 2019; 80:125-140. [PMID: 31071485 PMCID: PMC6553682 DOI: 10.1016/j.ceca.2019.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023]
Abstract
Several superfamilies of plasma membrane channels which regulate transmembrane ion flux have also been shown to regulate a multitude of cellular processes, including proliferation and migration. Ion channels are typically multimeric complexes consisting of conducting subunits and auxiliary, non-conducting subunits. Auxiliary subunits modulate the function of conducting subunits and have putative non-conducting roles, further expanding the repertoire of cellular processes governed by ion channel complexes to processes such as transcellular adhesion and gene transcription. Given this expansive influence of ion channels on cellular behaviour it is perhaps no surprise that aberrant ion channel expression is a common occurrence in cancer. This review will focus on the conducting and non-conducting roles of the auxiliary subunits of various Ca2+, K+, Na+ and Cl- channels and the burgeoning evidence linking such auxiliary subunits to cancer. Several subunits are upregulated (e.g. Cavβ, Cavγ) and downregulated (e.g. Kvβ) in cancer, while other subunits have been functionally implicated as oncogenes (e.g. Navβ1, Cavα2δ1) and tumour suppressor genes (e.g. CLCA2, KCNE2, BKγ1) based on in vivo studies. The strengthening link between ion channel auxiliary subunits and cancer has exposed these subunits as potential biomarkers and therapeutic targets. However further mechanistic understanding is required into how these subunits contribute to tumour progression before their therapeutic potential can be fully realised.
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Affiliation(s)
- Alexander S Haworth
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK
| | - William J Brackenbury
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK.
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12
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Yoshioka W, Tohyama C. Mechanisms of Developmental Toxicity of Dioxins and Related Compounds. Int J Mol Sci 2019; 20:E617. [PMID: 30708991 PMCID: PMC6387164 DOI: 10.3390/ijms20030617] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 12/20/2022] Open
Abstract
Dioxins and related compounds induce morphological abnormalities in developing animals in an aryl hydrocarbon receptor (AhR)-dependent manner. Here we review the studies in which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is used as a prototypical compound to elucidate the pathogenesis of morphological abnormalities. TCDD-induced cleft palate in fetal mice involves a delay in palatogenesis and dissociation of fused palate shelves. TCDD-induced hydronephrosis, once considered to be caused by the anatomical obstruction of the ureter, is now separated into TCDD-induced obstructive and non-obstructive hydronephrosis, which develops during fetal and neonatal periods, respectively. In the latter, a prostaglandin E₂ synthesis pathway and urine concentration system are involved. TCDD-induced abnormal development of prostate involves agenesis of the ventral lobe. A suggested mechanism is that AhR activation in the urogenital sinus mesenchyme by TCDD modulates the wingless-type MMTV integration site family (WNT)/β-catenin signaling cascade to interfere with budding from urogenital sinus epithelium. TCDD exposure to zebrafish embryos induces loss of epicardium progenitor cells and heart malformation. AHR2-dependent downregulation of Sox9b expression in cardiomyocytes is a suggested underlying mechanism. TCDD-induced craniofacial malformation in zebrafish is considered to result from the AHR2-dependent reduction in SRY-box 9b (SOX9b), probably partly via the noncoding RNA slincR, resulting in the underdevelopment of chondrocytes and cartilage.
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Affiliation(s)
- Wataru Yoshioka
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Chiharu Tohyama
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
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13
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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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14
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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15
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Nanami M, Pham TD, Kim YH, Yang B, Sutliff RL, Staub O, Klein JD, Lopez-Cayuqueo KI, Chambrey R, Park AY, Wang X, Pech V, Verlander JW, Wall SM. The Role of Intercalated Cell Nedd4-2 in BP Regulation, Ion Transport, and Transporter Expression. J Am Soc Nephrol 2018; 29:1706-1719. [PMID: 29773687 DOI: 10.1681/asn.2017080826] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 03/29/2018] [Indexed: 12/23/2022] Open
Abstract
BackgroundNedd4-2 is an E3 ubiquitin-protein ligase that associates with transport proteins, causing their ubiquitylation, and then internalization and degradation. Previous research has suggested a correlation between Nedd4-2 and BP. In this study, we explored the effect of intercalated cell (IC) Nedd4-2 gene ablation on IC transporter abundance and function and on BP.Methods We generated IC Nedd4-2 knockout mice using Cre-lox technology and produced global pendrin/Nedd4-2 null mice by breeding global Nedd4-2 null (Nedd4-2-/- ) mice with global pendrin null (Slc26a4-/- ) mice. Mice ate a diet with 1%-4% NaCl; BP was measured by tail cuff and radiotelemetry. We measured transepithelial transport of Cl- and total CO2 and transepithelial voltage in cortical collecting ducts perfused in vitro Transporter abundance was detected with immunoblots, immunohistochemistry, and immunogold cytochemistry.Results IC Nedd4-2 gene ablation markedly increased electroneutral Cl-/HCO3- exchange in the cortical collecting duct, although benzamil-, thiazide-, and bafilomycin-sensitive ion flux changed very little. IC Nedd4-2 gene ablation did not increase the abundance of type B IC transporters, such as AE4 (Slc4a9), H+-ATPase, barttin, or the Na+-dependent Cl-/HCO3- exchanger (Slc4a8). However, IC Nedd4-2 gene ablation increased CIC-5 total protein abundance, apical plasma membrane pendrin abundance, and the ratio of pendrin expression on the apical membrane to the cytoplasm. IC Nedd4-2 gene ablation increased BP by approximately 10 mm Hg. Moreover, pendrin gene ablation eliminated the increase in BP observed in global Nedd4-2 knockout mice.Conclusions IC Nedd4-2 regulates Cl-/HCO3- exchange in ICs., Nedd4-2 gene ablation increases BP in part through its action in these cells.
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Affiliation(s)
| | | | | | - Baoli Yang
- Department of Obstetrics and Gynecology, University of Iowa, Iowa City, Iowa
| | | | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch," Zurich, Switzerland
| | | | - Karen I Lopez-Cayuqueo
- Centro de Estudios Cientificos, Valdivia, Chile.,Institut National de la Santé et de la Recherche Médicale U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Regine Chambrey
- Institut National de la Santé et de la Recherche Médicale U1188, Universite de la Reunion, Plateforme Cyclotron Réunion Océan Indien, St. Denis, Ile de la Reunion, France; and
| | | | | | | | - Jill W Verlander
- Renal Division, Department of Medicine, University of Florida at Gainesville, Gainesville, Florida
| | - Susan M Wall
- Renal and .,Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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16
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Role of ClC-K and barttin in low potassium-induced sodium chloride cotransporter activation and hypertension in mouse kidney. Biosci Rep 2018; 38:BSR20171243. [PMID: 29326302 PMCID: PMC5789154 DOI: 10.1042/bsr20171243] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 12/22/2022] Open
Abstract
The sodium chloride cotransporter (NCC) has been identified as a key molecule regulating potassium balance. The mechanisms of NCC regulation during low extracellular potassium concentrations have been studied in vitro. These studies have shown that hyperpolarization increased chloride efflux, leading to the activation of chloride-sensitive with-no-lysine kinase (WNK) kinases and their downstream molecules, including STE20/SPS1-related proline/alanine-rich kinase (SPAK) and NCC. However, this mechanism was not studied in vivo. Previously, we developed the barttin hypomorphic mouse (Bsndneo/neo mice), expressing very low levels of barttin and ClC-K channels, because barttin is an essential β-subunit of ClC-K. In contrast with Bsnd−/− mice, Bsndneo/neo mice survived to adulthood. In Bsndneo/neo mice, SPAK and NCC activation after consuming a low-potassium diet was clearly impaired compared with that in wild-type (WT) mice. In ex vivo kidney slice experiment, the increase in pNCC and SPAK in low-potassium medium was also impaired in Bsndneo/neo mice. Furthermore, increased blood pressure was observed in WT mice fed a high-salt and low-potassium diet, which was not evident in Bsndneo/neo mice. Thus, our study provides in vivo evidence that, in response to a low-potassium diet, ClC-K and barttin play important roles in the activation of the WNK4-SPAK-NCC cascade and blood pressure regulation.
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17
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Seidel E, Scholl UI. Genetic mechanisms of human hypertension and their implications for blood pressure physiology. Physiol Genomics 2017; 49:630-652. [PMID: 28887369 DOI: 10.1152/physiolgenomics.00032.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Hypertension, or elevated blood pressure, constitutes a major public health burden that affects more than 1 billion people worldwide and contributes to ~9 million deaths annually. Hereditary factors are thought to contribute to up to 50% of interindividual blood pressure variability. Blood pressure in the general population approximately shows a normal distribution and is thought to be a polygenic trait. In rare cases, early-onset hypertension or hypotension are inherited as Mendelian traits. The identification of the underlying Mendelian genes and variants has contributed to our understanding of the physiology of blood pressure regulation, emphasizing renal salt handling and the renin angiotensin aldosterone system as players in the determination of blood pressure. Genome-wide association studies (GWAS) have revealed more than 100 variants that are associated with blood pressure, typically with small effect sizes, which cumulatively explain ~3.5% of blood pressure trait variability. Several GWAS associations point to a role of the vasculature in the pathogenesis of hypertension. Despite these advances, the majority of the genetic contributors to blood pressure regulation are currently unknown; whether large-scale exome or genome sequencing studies will unravel these factors remains to be determined.
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Affiliation(s)
- Eric Seidel
- Department of Nephrology, Medical School, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ute I Scholl
- Department of Nephrology, Medical School, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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18
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Hofmeister AF, Kömhoff M, Weber S, Grgic I. Disease modeling in genetic kidney diseases: mice. Cell Tissue Res 2017; 369:159-170. [PMID: 28601904 DOI: 10.1007/s00441-017-2639-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 05/04/2017] [Indexed: 12/27/2022]
Abstract
The mouse still represents arguably the most important mammal organism in research for modeling human genetic kidney diseases in vivo. Compared with many other mammal species, the breeding and maintenance of mice in the laboratory is relatively simple and cheap and reproduction cycles are short. In addition to classic gene knockout mouse lines, new molecular biological technologies have led to the development of a plethora of other, more sophisticated, mouse models, allowing the targeting of genes or gene function in a cell-specific, tissue-specific and time-dependent fashion. With the refinement of more recently developed genome-editing technologies, including the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas system and other engineered nucleases such as zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs), our "tool set" of mouse models is expected to rapidly expand. These technological advances hold great promise and should enable us to study and hence understand the biology of inherited kidney diseases in greater detail. By analogy, we may be able to answer questions regarding the impact of individual proteins on the development of human kidney disorders, the underlying mechanisms governing the evolution of the disease and the predicted responsiveness to therapeutic interventions. Moreover, knockout and transgenic mouse models can be highly informative with respect to the effects of genetic variations on renal phenotypes. This review focuses on mouse models that have been devised primarily to study monogenic human kidney diseases, which are typically caused by a single abnormal gene and passed on in a Mendelian pattern. Despite the large number of human hereditary kidney disorders and the multitude of mouse models described in the literature, we attempt to give a balanced overview of several well-known renal pathologies, a few of which are addressed in some detail.
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Affiliation(s)
- Andreas F Hofmeister
- Department of Internal Medicine and Nephrology, University Hospital Giessen and Marburg, Philipps-University Marburg, Baldingerstrasse 1, 35033, Marburg, Germany
| | - Martin Kömhoff
- University Children's Hospital, Philipps-University Marburg, Marburg, Germany
| | - Stefanie Weber
- University Children's Hospital, Philipps-University Marburg, Marburg, Germany
| | - Ivica Grgic
- Department of Internal Medicine and Nephrology, University Hospital Giessen and Marburg, Philipps-University Marburg, Baldingerstrasse 1, 35033, Marburg, Germany.
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Calcineurin inhibitors block sodium-chloride cotransporter dephosphorylation in response to high potassium intake. Kidney Int 2016; 91:402-411. [PMID: 28341239 DOI: 10.1016/j.kint.2016.09.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/25/2016] [Accepted: 09/01/2016] [Indexed: 11/23/2022]
Abstract
Dietary potassium intake is inversely related to blood pressure and mortality. Moreover, the sodium-chloride cotransporter (NCC) plays an important role in blood pressure regulation and urinary potassium excretion in response to potassium intake. Previously, it was shown that NCC is activated by the WNK4-SPAK cascade and dephosphorylated by protein phosphatase. However, the mechanism of NCC regulation with acute potassium intake is still unclear. To identify the molecular mechanism of NCC regulation in response to potassium intake, we used adult C57BL/6 mice fed a 1.7% potassium solution by oral gavage. We confirmed that acute potassium load rapidly dephosphorylated NCC, which was not dependent on the accompanying anions. Mice were treated with tacrolimus (calcineurin inhibitor) and W7 (calmodulin inhibitor) before the oral potassium loads. Dephosphorylation of NCC induced by potassium was significantly inhibited by both tacrolimus and W7 treatment. There was no significant difference in WNK4, OSR1, and SPAK expression after high potassium intake, even after tacrolimus and W7 treatment. Another phosphatase, protein phosphatase 1, and its endogenous inhibitor I-1 did not show a significant change after potassium intake. Hyperkaliuria, induced by high potassium intake, was significantly suppressed by tacrolimus treatment. Thus, calcineurin is activated by an acute potassium load, which rapidly dephosphorylates NCC, leading to increased urinary potassium excretion.
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Yoshioka W, Kawaguchi T, Nishimura N, Akagi T, Fujisawa N, Yanagisawa H, Matsumura F, Tohyama C. Polyuria-associated hydronephrosis induced by xenobiotic chemical exposure in mice. Am J Physiol Renal Physiol 2016; 311:F752-F762. [DOI: 10.1152/ajprenal.00001.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 07/16/2016] [Indexed: 12/19/2022] Open
Abstract
Hydronephrosis is a commonly found disease state characterized by the dilation of renal calices and pelvis, resulting in the loss of kidney function in the severest cases. A generally accepted etiology of hydronephrosis involves the obstruction of urine flow along the urinary tract. In the recent years, we have developed a mouse model of hydronephrosis induced by lactational exposure to dioxin and demonstrated a lack of anatomical obstruction in this model. We also showed that prostaglandin E2 synthesis system plays a critical role in the onset of hydronephrosis. In the present study, we found that neonatal hydronephrosis was not likely to be associated with functional obstruction (impaired peristalsis) but was found to be associated with polyuria and low urine osmolality with the downregulation of proteins involved in the urine concentrating process. The administration of an antidiuretic hormone analog to the dioxin-exposed pups not only suppressed the increased urine output but also decreased the incidence and severity of hydronephrosis. In contrast to the case in pups, administration of dioxin to adult mice failed to induce polyuria and upregulation of prostaglandin E2 synthesis system, and the adult mice were resistant to develop hydronephrosis. These findings suggest the possibility that polyuria could induce hydronephrosis in the absence of anatomical or functional obstruction of the ureter. It is concluded that the present animal model provides a unique example of polyuria-associated type of hydronephrosis, suggesting a need to redefine this disease state.
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Affiliation(s)
- Wataru Yoshioka
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Public Health and Environmental Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Tatsuya Kawaguchi
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noriko Nishimura
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Toshiya Akagi
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Nozomi Fujisawa
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Yanagisawa
- Department of Public Health and Environmental Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Fumio Matsumura
- Department of Environmental Toxicology and Center for Environmental Health Sciences, University of California, Davis, California; and
| | - Chiharu Tohyama
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
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21
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Barrallo-Gimeno A, Gradogna A, Zanardi I, Pusch M, Estévez R. Regulatory-auxiliary subunits of CLC chloride channel-transport proteins. J Physiol 2016; 593:4111-27. [PMID: 25762128 DOI: 10.1113/jp270057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/15/2015] [Indexed: 02/06/2023] Open
Abstract
The CLC family of chloride channels and transporters is composed by nine members, but only three of them, ClC-Ka/b, ClC-7 and ClC-2, have been found so far associated with auxiliary subunits. These CLC regulatory subunits are small proteins that present few common characteristics among them, both structurally and functionally, and their effects on the corresponding CLC protein are different. Barttin, a protein with two transmembrane domains, is essential for the membrane localization of ClC-K proteins and their activity in the kidney and inner ear. Ostm1 is a protein with a single transmembrane domain and a highly glycosylated N-terminus. Unlike the other two CLC auxiliary subunits, Ostm1 shows a reciprocal relationship with ClC-7 for their stability. The subcellular localization of Ostm1 depends on ClC-7 and not the other way around. ClC-2 is active on its own, but GlialCAM, a transmembrane cell adhesion molecule with two extracellular immunoglobulin (Ig)-like domains, regulates its subcellular localization and activity in glial cells. The common theme for these three proteins is their requirement for a proper homeostasis, since their malfunction leads to distinct diseases. We will review here their properties and their role in normal chloride physiology and the pathological consequences of their improper function.
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Affiliation(s)
- Alejandro Barrallo-Gimeno
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, University of Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
| | | | - Ilaria Zanardi
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genoa, Italy
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genoa, Italy
| | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, University of Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
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22
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Stölting G, Bungert-Plümke S, Franzen A, Fahlke C. Carboxyl-terminal Truncations of ClC-Kb Abolish Channel Activation by Barttin Via Modified Common Gating and Trafficking. J Biol Chem 2015; 290:30406-16. [PMID: 26453302 DOI: 10.1074/jbc.m115.675827] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Indexed: 12/21/2022] Open
Abstract
ClC-K chloride channels are crucial for auditory transduction and urine concentration. Mutations in CLCNKB, the gene encoding the renal chloride channel hClC-Kb, cause Bartter syndrome type III, a human genetic condition characterized by polyuria, hypokalemia, and alkalosis. In recent years, several Bartter syndrome-associated mutations have been described that result in truncations of the intracellular carboxyl terminus of hClC-Kb. We here used a combination of whole-cell patch clamp, confocal imaging, co-immunoprecipitation, and surface biotinylation to study the functional consequences of a frequent CLCNKB mutation that creates a premature stop codon at Trp-610. We found that W610X leaves the association of hClC-Kb and the accessory subunit barttin unaffected, but impairs its regulation by barttin. W610X attenuates hClC-Kb surface membrane insertion. Moreover, W610X results in hClC-Kb channel opening in the absence of barttin and prevents further barttin-mediated activation. To describe how the carboxyl terminus modifies the regulation by barttin we used V166E rClC-K1. V166E rClC-K1 is active without barttin and exhibits prominent, barttin-regulated voltage-dependent gating. Electrophysiological characterization of truncated V166E rClC-K1 demonstrated that the distal carboxyl terminus is necessary for slow cooperative gating. Since barttin modifies this particular gating process, channels lacking the distal carboxyl-terminal domain are no longer regulated by the accessory subunit. Our results demonstrate that the carboxyl terminus of hClC-Kb is not part of the binding site for barttin, but functionally modifies the interplay with barttin. The loss-of-activation of truncated hClC-Kb channels in heterologous expression systems fully explains the reduced basolateral chloride conductance in affected kidneys and the clinical symptoms of Bartter syndrome patients.
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Affiliation(s)
- Gabriel Stölting
- From the Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, 52425 Jülich
| | - Stefanie Bungert-Plümke
- From the Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, 52425 Jülich
| | - Arne Franzen
- From the Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, 52425 Jülich
| | - Christoph Fahlke
- From the Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, 52425 Jülich
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23
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Jentsch TJ. Discovery of CLC transport proteins: cloning, structure, function and pathophysiology. J Physiol 2015; 593:4091-109. [PMID: 25590607 DOI: 10.1113/jp270043] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/11/2015] [Indexed: 02/06/2023] Open
Abstract
After providing a personal description of the convoluted path leading 25 years ago to the molecular identification of the Torpedo Cl(-) channel ClC-0 and the discovery of the CLC gene family, I succinctly describe the general structural and functional features of these ion transporters before giving a short overview of mammalian CLCs. These can be categorized into plasma membrane Cl(-) channels and vesicular Cl(-) /H(+) -exchangers. They are involved in the regulation of membrane excitability, transepithelial transport, extracellular ion homeostasis, endocytosis and lysosomal function. Diseases caused by CLC dysfunction include myotonia, neurodegeneration, deafness, blindness, leukodystrophy, male infertility, renal salt loss, kidney stones and osteopetrosis, revealing a surprisingly broad spectrum of biological roles for chloride transport that was unsuspected when I set out to clone the first voltage-gated chloride channel.
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Affiliation(s)
- Thomas J Jentsch
- Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
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24
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Uetsuka S, Ogata G, Nagamori S, Isozumi N, Nin F, Yoshida T, Komune S, Kitahara T, Kikkawa Y, Inohara H, Kanai Y, Hibino H. Molecular architecture of the stria vascularis membrane transport system, which is essential for physiological functions of the mammalian cochlea. Eur J Neurosci 2015; 42:1984-2002. [PMID: 26060893 DOI: 10.1111/ejn.12973] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/02/2015] [Accepted: 06/02/2015] [Indexed: 11/29/2022]
Abstract
Stria vascularis of the mammalian cochlea transports K(+) to establish the electrochemical property in the endolymph crucial for hearing. This epithelial tissue also transports various small molecules. To clarify the profile of proteins participating in the transport system in the stria vascularis, membrane components purified from the stria of adult rats were analysed by liquid chromatography tandem mass spectrometry. Of the 3236 proteins detected in the analysis, 1807 were membrane proteins. Ingenuity Knowledge Base and literature data identified 513 proteins as being expressed on the 'plasma membrane', these included 25 ion channels and 79 transporters. Sixteen of the former and 62 of the latter had not yet been identified in the stria. Unexpectedly, many Cl(-) and Ca(2+) transport systems were found, suggesting that the dynamics of these ions play multiple roles. Several transporters for organic substances were also detected. Network analysis demonstrated that a few kinases, including protein kinase A, and Ca(2+) were key regulators for the strial transports. In the library of channels and transporters, 19 new candidates for uncloned deafness-related genes were identified. These resources provide a platform for understanding the molecular mechanisms underlying the epithelial transport essential for cochlear function and the pathophysiological processes involved in hearing disorders.
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Affiliation(s)
- Satoru Uetsuka
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan.,Department of Otorhinolaryngology - Head and Neck Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Genki Ogata
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan
| | - Shushi Nagamori
- Division of Bio-system Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Noriyoshi Isozumi
- Division of Bio-system Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan
| | - Takamasa Yoshida
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan.,Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shizuo Komune
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tadashi Kitahara
- Department of Otorhinolaryngology - Head and Neck Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan.,Department of Otorhinolaryngology - Head and Neck Surgery, Nara Medical University, Nara, Japan
| | - Yoshiaki Kikkawa
- Mammalian Genetics Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hidenori Inohara
- Department of Otorhinolaryngology - Head and Neck Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yoshikatsu Kanai
- Division of Bio-system Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan
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25
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Wakui H, Uneda K, Tamura K, Ohsawa M, Azushima K, Kobayashi R, Ohki K, Dejima T, Kanaoka T, Tsurumi-Ikeya Y, Matsuda M, Haruhara K, Nishiyama A, Yabana M, Fujikawa T, Yamashita A, Umemura S. Renal tubule angiotensin II type 1 receptor-associated protein promotes natriuresis and inhibits salt-sensitive blood pressure elevation. J Am Heart Assoc 2015; 4:e001594. [PMID: 25792129 PMCID: PMC4392439 DOI: 10.1161/jaha.114.001594] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Angiotensin II type 1 receptor (AT1R)-associated protein (ATRAP; Agtrap gene) promotes AT1R internalization along with suppression of pathological AT1R activation. In this study, we examined whether enhancement of ATRAP in the renal distal tubules affects sodium handling and blood pressure regulation in response to high salt (HS) loading, using ATRAP transgenic mice on a salt-sensitive C57BL/6J background. METHODS AND RESULTS Renal ATRAP transgenic (rATRAP-Tg) mice, which exhibit renal tubule-dominant ATRAP enhancement, and their wild-type littermate C57BL/6J mice on a normal salt diet (0.3% NaCl) at baseline were subjected to dietary HS loading (4% NaCl) for 7 days. In rATRAP-Tg mice, the dietary HS loading-mediated blood pressure elevation was suppressed compared with wild-type mice, despite similar baseline blood pressure. Although renal angiotensin II level was comparable in rATRAP-Tg and wild-type mice with and without HS loading, urinary sodium excretion in response to HS loading was significantly enhanced in the rATRAP-Tg mice. In addition, functional transport activity of the amiloride-sensitive epithelial Na(+) channel was significantly decreased under saline volume-expanded conditions in rATRAP-Tg mice compared with wild-type mice, without any evident change in epithelial Na(+) channel protein expression. Plasma membrane AT1R expression in the kidney of rATRAP-Tg mice was decreased compared with wild-type mice. CONCLUSIONS These results demonstrated that distal tubule-dominant enhancement of ATRAP inhibits pathological renal sodium reabsorption and blood pressure elevation in response to HS loading. The findings suggest that ATRAP-mediated modulation of sodium handling in renal distal tubules could be a target of interest in salt-sensitive blood pressure regulation.
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Affiliation(s)
- Hiromichi Wakui
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Kazushi Uneda
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Kouichi Tamura
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Masato Ohsawa
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Kengo Azushima
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Ryu Kobayashi
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Kohji Ohki
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Toru Dejima
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Tomohiko Kanaoka
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Yuko Tsurumi-Ikeya
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Miyuki Matsuda
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Kotaro Haruhara
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University School of Medicine, Kagawa, Japan (A.N.)
| | - Machiko Yabana
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Tetsuya Fujikawa
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
| | - Akio Yamashita
- Department of Molecular Biology, Yokohama City University Graduate School of Medicine, Yokohama, Japan (A.Y.)
| | - Satoshi Umemura
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan (H.W., K.U., K.T., M.O., K.A., R.K., K.O., T.D., T.K., Y.T.I., M.M., K.H., M.Y., T.F., S.U.)
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Stölting G, Fischer M, Fahlke C. CLC channel function and dysfunction in health and disease. Front Physiol 2014; 5:378. [PMID: 25339907 PMCID: PMC4188032 DOI: 10.3389/fphys.2014.00378] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/12/2014] [Indexed: 01/01/2023] Open
Abstract
CLC channels and transporters are expressed in most tissues and fulfill diverse functions. There are four human CLC channels, ClC-1, ClC-2, ClC-Ka, and ClC-Kb, and five CLC transporters, ClC-3 through −7. Some of the CLC channels additionally associate with accessory subunits. Whereas barttin is mandatory for the functional expression of ClC-K, GlialCam is a facultative subunit of ClC-2 which modifies gating and thus increases the functional variability within the CLC family. Isoform-specific ion conduction and gating properties optimize distinct CLC channels for their cellular tasks. ClC-1 preferentially conducts at negative voltages, and the resulting inward rectification provides a large resting chloride conductance without interference with the muscle action potential. Exclusive opening at voltages negative to the chloride reversal potential allows for ClC-2 to regulate intracellular chloride concentrations. ClC-Ka and ClC-Kb are equally suited for inward and outward currents to support transcellular chloride fluxes. Every human CLC channel gene has been linked to a genetic disease, and studying these mutations has provided much information about the physiological roles and the molecular basis of CLC channel function. Mutations in the gene encoding ClC-1 cause myotonia congenita, a disease characterized by sarcolemmal hyperexcitability and muscle stiffness. Loss-of-function of ClC-Kb/barttin channels impairs NaCl resorption in the limb of Henle and causes hyponatriaemia, hypovolemia and hypotension in patients suffering from Bartter syndrome. Mutations in CLCN2 were found in patients with CNS disorders but the functional role of this isoform is still not understood. Recent links between ClC-1 and epilepsy and ClC-Ka and heart failure suggested novel cellular functions of these proteins. This review aims to survey the knowledge about physiological and pathophysiological functions of human CLC channels in the light of recent discoveries from biophysical, physiological, and genetic studies.
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Affiliation(s)
- Gabriel Stölting
- Institute of Complex Systems-Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich Jülich, Germany
| | - Martin Fischer
- Institut für Neurophysiologie, Medizinische Hochschule Hannover Hannover, Germany
| | - Christoph Fahlke
- Institute of Complex Systems-Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich Jülich, Germany
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27
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Ohsawa M, Tamura K, Wakui H, Maeda A, Dejima T, Kanaoka T, Azushima K, Uneda K, Tsurumi-Ikeya Y, Kobayashi R, Matsuda M, Uchida S, Toya Y, Kobori H, Nishiyama A, Yamashita A, Ishikawa Y, Umemura S. Deletion of the angiotensin II type 1 receptor-associated protein enhances renal sodium reabsorption and exacerbates angiotensin II-mediated hypertension. Kidney Int 2014; 86:570-81. [PMID: 24694992 PMCID: PMC4149871 DOI: 10.1038/ki.2014.95] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 02/07/2014] [Accepted: 02/13/2014] [Indexed: 12/13/2022]
Abstract
Angiotensin II type 1 receptor (AT1R)–associated protein (ATRAP) promotes AT1R internalization along with suppression of pathological activation of tissue AT1R signaling. However, the functional significance of ATRAP in renal sodium handling and blood pressure regulation under pathological stimuli is not fully resolved. Here we show the blood pressure of mice with a gene-targeted disruption of ATRAP was comparable to that of wild-type mice at baseline. However, in ATRAP-knockout mice, angiotensin II–induced hypertension was exacerbated and the extent of positive sodium balance was increased by angiotensin II. Renal expression of the sodium-proton antiporter 3, a major sodium transporter in the proximal tubules, urinary pH, renal angiotensinogen production, and angiotensin II content was unaffected. Stimulation of the renal expression and activity of the epithelial sodium channel (ENaC), a major sodium transporter in the distal tubules, was significantly enhanced by chronic angiotensin II infusion. The circulating and urinary aldosterone levels were comparable. The blood pressure response and renal ENaC expression by aldosterone were not affected. Thus, ATRAP deficiency exacerbated angiotensin II–mediated hypertension by pathological activation of renal tubular AT1R by angiotensin II. This directly stimulates ENaC in the distal tubules and enhances sodium retention in an aldosterone-independent manner.
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Affiliation(s)
- Masato Ohsawa
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kouichi Tamura
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hiromichi Wakui
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Akinobu Maeda
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Toru Dejima
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Tomohiko Kanaoka
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kengo Azushima
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazushi Uneda
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yuko Tsurumi-Ikeya
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Ryu Kobayashi
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Miyuki Matsuda
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoshiyuki Toya
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hiroyuki Kobori
- Department of Pharmacology, Kagawa University School of Medicine, Kagawa, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University School of Medicine, Kagawa, Japan
| | - Akio Yamashita
- Department of Molecular Biology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yoshihiro Ishikawa
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Satoshi Umemura
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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Treatment with 17-allylamino-17-demethoxygeldanamycin ameliorated symptoms of Bartter syndrome type IV caused by mutated Bsnd in mice. Biochem Biophys Res Commun 2013; 441:544-9. [PMID: 24189473 DOI: 10.1016/j.bbrc.2013.10.129] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 10/24/2013] [Indexed: 11/21/2022]
Abstract
Mutations of BSND, which encodes barttin, cause Bartter syndrome type IV. This disease is characterized by salt and fluid loss, hypokalemia, metabolic alkalosis, and sensorineural hearing impairment. Barttin is the β-subunit of the ClC-K chloride channel, which recruits it to the plasma membranes, and the ClC-K/barttin complex contributes to transepithelial chloride transport in the kidney and inner ear. The retention of mutant forms of barttin in the endoplasmic reticulum (ER) is etiologically linked to Bartter syndrome type IV. Here, we report that treatment with 17-allylamino-17-demethoxygeldanamycin (17-AAG), an Hsp90 inhibitor, enhanced the plasma membrane expression of mutant barttins (R8L and G47R) in Madin-Darby canine kidney cells. Administration of 17-AAG to Bsnd(R8L/R8L) knock-in mice elevated the plasma membrane expression of R8L in the kidney and inner ear, thereby mitigating hypokalemia, metabolic alkalosis, and hearing loss. These results suggest that drugs that rescue ER-retained mutant barttin may be useful for treating patients with Bartter syndrome type IV.
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Denton JS, Pao AC, Maduke M. Novel diuretic targets. Am J Physiol Renal Physiol 2013; 305:F931-42. [PMID: 23863472 PMCID: PMC3798746 DOI: 10.1152/ajprenal.00230.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 07/12/2013] [Indexed: 01/11/2023] Open
Abstract
As the molecular revolution continues to inform a deeper understanding of disease mechanisms and pathways, there exist unprecedented opportunities for translating discoveries at the bench into novel therapies for improving human health. Despite the availability of several different classes of antihypertensive medications, only about half of the 67 million Americans with hypertension manage their blood pressure appropriately. A broader selection of structurally diverse antihypertensive drugs acting through different mechanisms would provide clinicians with greater flexibility in developing effective treatment regimens for an increasingly diverse and aging patient population. An emerging body of physiological, genetic, and pharmacological evidence has implicated several renal ion-transport proteins, or regulators thereof, as novel, yet clinically unexploited, diuretic targets. These include the renal outer medullary potassium channel, ROMK (Kir1.1), Kir4.1/5.1 potassium channels, ClC-Ka/b chloride channels, UTA/B urea transporters, the chloride/bicarbonate exchanger pendrin, and the STE20/SPS1-related proline/alanine-rich kinase (SPAK). The molecular pharmacology of these putative targets is poorly developed or lacking altogether; however, recent efforts by a few academic and pharmaceutical laboratories have begun to lessen this critical barrier. Here, we review the evidence in support of the aforementioned proteins as novel diuretic targets and highlight examples where progress toward developing small-molecule pharmacology has been made.
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Affiliation(s)
- Jerod S Denton
- T4208 Medical Center North, 1161 21st Ave. South, Nashville, TN 37232.
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30
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Rossier BC, Staub O, Hummler E. Genetic dissection of sodium and potassium transport along the aldosterone-sensitive distal nephron: importance in the control of blood pressure and hypertension. FEBS Lett 2013; 587:1929-41. [PMID: 23684652 DOI: 10.1016/j.febslet.2013.05.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
Abstract
In this review, we discuss genetic evidence supporting Guyton's hypothesis stating that blood pressure control is critically depending on fluid handling by the kidney. The review is focused on the genetic dissection of sodium and potassium transport in the distal nephron and the collecting duct that are the most important sites for the control of sodium and potassium balance by aldosterone and angiotensin II. Thanks to the study of Mendelian forms of hypertension and their corresponding transgenic mouse models, three main classes of diuretic receptors (furosemide, thiazide, amiloride) and the main components of the aldosterone- and angiotensin-dependent signaling pathways were molecularly identified over the past 20 years. This will allow to design rational strategies for the treatment of hypertension and for the development of the next generation of diuretics.
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Cheval L, Pierrat F, Rajerison R, Piquemal D, Doucet A. Of mice and men: divergence of gene expression patterns in kidney. PLoS One 2012; 7:e46876. [PMID: 23056504 PMCID: PMC3463552 DOI: 10.1371/journal.pone.0046876] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 09/10/2012] [Indexed: 11/28/2022] Open
Abstract
Since the development of methods for homologous gene recombination, mouse models have played a central role in research in renal pathophysiology. However, many published and unpublished results show that mice with genetic changes mimicking human pathogenic mutations do not display the human phenotype. These functional differences may stem from differences in gene expression between mouse and human kidneys. However, large scale comparison of gene expression networks revealed conservation of gene expression among a large panel of human and mouse tissues including kidneys. Because renal functions result from the spatial integration of elementary processes originating in the glomerulus and the successive segments constituting the nephron, we hypothesized that differences in gene expression profiles along the human and mouse nephron might account for different behaviors. Analysis of SAGE libraries generated from the glomerulus and seven anatomically defined nephron segments from human and mouse kidneys allowed us to identify 4644 pairs of gene orthologs expressed in either one or both species. Quantitative analysis shows that many transcripts are present at different levels in the two species. It also shows poor conservation of gene expression profiles, with less than 10% of the 4644 gene orthologs displaying a higher conservation of expression profiles than the neutral expectation (p<0.05). Accordingly, hierarchical clustering reveals a higher degree of conservation of gene expression patterns between functionally unrelated kidney structures within a given species than between cognate structures from the two species. Similar findings were obtained for sub-groups of genes with either kidney-specific or housekeeping functions. Conservation of gene expression at the scale of the whole organ and divergence at the level of its constituting sub-structures likely account for the fact that although kidneys assume the same global function in the two species, many mouse “models” of human pathologies do not display the expected phenotype.
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Affiliation(s)
- Lydie Cheval
- Unité Mixte de Recherche 872, Université Paris 6 and Institut National de la Santé et de la Recherche Médicale, Paris, France
- Equipe de Recherche 7226, Centre National de la Recherche Scientifique, Paris, France
| | | | - Rabary Rajerison
- Unité Mixte de Recherche 872, Université Paris 6 and Institut National de la Santé et de la Recherche Médicale, Paris, France
- Equipe de Recherche 7226, Centre National de la Recherche Scientifique, Paris, France
| | | | - Alain Doucet
- Unité Mixte de Recherche 872, Université Paris 6 and Institut National de la Santé et de la Recherche Médicale, Paris, France
- Equipe de Recherche 7226, Centre National de la Recherche Scientifique, Paris, France
- * E-mail:
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32
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Affiliation(s)
- Ivana Y Kuo
- Departments of †Pharmacology and ‡Cellular and Molecular Physiology School of Medicine, Yale University , 333 Cedar Street, New Haven, Connecticut 06520
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Xuan W, Pan R, Cao Y, Liu K, Wang W. A fluorescent probe capable of detecting H2S at submicromolar concentrations in cells. Chem Commun (Camb) 2012; 48:10669-71. [DOI: 10.1039/c2cc35602c] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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34
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Oi K, Sohara E, Rai T, Misawa M, Chiga M, Alessi DR, Sasaki S, Uchida S. A minor role of WNK3 in regulating phosphorylation of renal NKCC2 and NCC co-transporters in vivo. Biol Open 2011; 1:120-7. [PMID: 23213404 PMCID: PMC3507202 DOI: 10.1242/bio.2011048] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mutations in WNK1 and WNK4 kinase genes have been shown to cause a human hereditary hypertensive disease, pseudohypoaldosteronism type II (PHAII). We previously discovered that WNK kinases phosphorylate and activate OSR1/SPAK kinases that regulate renal SLC12A family transporters such as NKCC2 and NCC, and clarified that the constitutive activation of this cascade causes PHAII. WNK3, another member of the WNK kinase family, was reported to be a strong activator of NCC/NKCC2 when assayed in Xenopus oocytes, suggesting that WNK3 also plays a major role in regulating blood pressure and sodium reabsorption in the kidney. However, it remains to be determined whether WNK3 is in fact involved in the regulation of these transporters in vivo. To clarify this issue, we generated and analyzed WNK3 knockout mice. Surprisingly, phosphorylation and expression of OSR1, SPAK, NKCC2 and NCC did not decrease in knockout mouse kidney under normal and low-salt diets. Similarly, expression of epithelial Na channel and Na/H exchanger 3 were not affected in knockout mice. Na+ and K+ excretion in urine in WNK3 knockout mice was not affected under different salt diets. Blood pressure in WNK3 knockout mice was not lower under normal diet. However, lower blood pressure was observed in WNK3 knockout mice fed low-salt diet. WNK4 and WNK1 expression was slightly elevated in the knockout mice under low-salt diet, suggesting compensation for WNK3 knockout by these WNKs. Thus, WNK3 may have some role in the WNK-OSR1/SPAK-NCC/NKCC2 signal cascade in the kidney, but its contribution to total WNK kinase activity may be minimal.
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Affiliation(s)
- Katsuyuki Oi
- 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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