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Yanda MK, Ciobanu C, Guggino WB, Cebotaru L. CFTR and PC2, partners in the primary cilia in autosomal dominant polycystic kidney disease. Am J Physiol Cell Physiol 2023; 325:C682-C693. [PMID: 37519231 PMCID: PMC10635646 DOI: 10.1152/ajpcell.00197.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/13/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
Defects in the primary cilium are associated with autosomal dominant polycystic kidney disease (ADPKD). We used a combination of animal models, Western blotting, and confocal microscopy and discovered that CFTR and polycystin 2 (PC2) are both colocalized to the cilium in normal kidneys, with the levels of both being decreased in cystic epithelia. Cilia were longer in CFTR-null mice and in cystic cells in our ADPKD animal models. We examined septin 2, known to play a role in cilia length, to act as a diffusion barrier and to serve as an enhancer of proliferation. We found that septin 2 protein levels were upregulated and colocalized strongly with CFTR in cystic cells. Application of VX-809, the CFTR corrector, restored CFTR and PC2 toward normal in the cilia, decreased the protein levels of septin 2, and drastically reduced septin 2 colocalization with CFTR. Our data suggest that CFTR is present in the cilia and plays a role there, perhaps through its conductance of Cl-. We also postulate that septin 2 is important for localizing CFTR to the apical membrane in cystic epithelia.NEW & NOTEWORTHY CFTR is present in the primary cilia together with polycystin 2 (PC2). Ablation of CFTR makes cilia longer suggesting that CFTR plays a role there, perhaps through its conductance of Cl.
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Affiliation(s)
- Murali K Yanda
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Cristian Ciobanu
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - William B Guggino
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Liudmila Cebotaru
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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2
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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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3
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Cheng CJ, Rodan AR, Huang CL. Emerging Targets of Diuretic Therapy. Clin Pharmacol Ther 2017; 102:420-435. [PMID: 28560800 DOI: 10.1002/cpt.754] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/15/2017] [Accepted: 05/21/2017] [Indexed: 12/14/2022]
Abstract
Diuretics are commonly prescribed for treatment in patients with hypertension, edema, or heart failure. Studies on hypertensive and salt-losing disorders and on urea transporters have contributed to better understanding of mechanisms of renal salt and water reabsorption and their regulation. Proteins involved in the regulatory pathways are emerging targets for diuretic and aquaretic therapy. Integrative high-throughput screening, protein structure analysis, and chemical modification have identified promising agents for preclinical testing in animals. These include WNK-SPAK inhibitors, ClC-K channel antagonists, ROMK channel antagonists, and pendrin and urea transporter inhibitors. We discuss the potential advantages and side effects of these potential diuretics.
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Affiliation(s)
- C-J Cheng
- Department of Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Taipei, 114, Taiwan
| | - A R Rodan
- Department of Medicine, Division of Nephrology, University of Utah, Salt Lake City, Utah, USA
| | - C-L Huang
- Department of Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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4
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Hennings JC, Andrini O, Picard N, Paulais M, Huebner AK, Cayuqueo IKL, Bignon Y, Keck M, Cornière N, Böhm D, Jentsch TJ, Chambrey R, Teulon J, Hübner CA, Eladari D. The ClC-K2 Chloride Channel Is Critical for Salt Handling in the Distal Nephron. J Am Soc Nephrol 2016; 28:209-217. [PMID: 27335120 DOI: 10.1681/asn.2016010085] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/04/2016] [Indexed: 11/03/2022] Open
Abstract
Chloride transport by the renal tubule is critical for blood pressure (BP), acid-base, and potassium homeostasis. Chloride uptake from the urinary fluid is mediated by various apical transporters, whereas basolateral chloride exit is thought to be mediated by ClC-Ka/K1 and ClC-Kb/K2, two chloride channels from the ClC family, or by KCl cotransporters from the SLC12 gene family. Nevertheless, the localization and role of ClC-K channels is not fully resolved. Because inactivating mutations in ClC-Kb/K2 cause Bartter syndrome, a disease that mimics the effects of the loop diuretic furosemide, ClC-Kb/K2 is assumed to have a critical role in salt handling by the thick ascending limb. To dissect the role of this channel in detail, we generated a mouse model with a targeted disruption of the murine ortholog ClC-K2. Mutant mice developed a Bartter syndrome phenotype, characterized by renal salt loss, marked hypokalemia, and metabolic alkalosis. Patch-clamp analysis of tubules isolated from knockout (KO) mice suggested that ClC-K2 is the main basolateral chloride channel in the thick ascending limb and in the aldosterone-sensitive distal nephron. Accordingly, ClC-K2 KO mice did not exhibit the natriuretic response to furosemide and exhibited a severely blunted response to thiazide. We conclude that ClC-Kb/K2 is critical for salt absorption not only by the thick ascending limb, but also by the distal convoluted tubule.
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Affiliation(s)
- J Christopher Hennings
- Institut für Humangenetik, University Hospital Jena, Friedrich-Schiller-Universität, Jena, Germany
| | - Olga Andrini
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche en Santé 1138, Université Pierre et Marie Curie, Centre de Recherche des Cordeliers, Paris, France
| | - Nicolas Picard
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche en Santé 1138, Université Pierre et Marie Curie, Centre de Recherche des Cordeliers, Paris, France
| | - Marc Paulais
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche en Santé 1138, Université Pierre et Marie Curie, Centre de Recherche des Cordeliers, Paris, France
| | - Antje K Huebner
- Institut für Humangenetik, University Hospital Jena, Friedrich-Schiller-Universität, Jena, Germany
| | - Irma Karen Lopez Cayuqueo
- Institut National de la Santé et de la Recherche Médicale U970, Paris Cardiovascular Research Center, Paris, France.,Centro de Estudios Científicos, Valdivia, Chile
| | - Yohan Bignon
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche en Santé 1138, Université Pierre et Marie Curie, Centre de Recherche des Cordeliers, Paris, France
| | - Mathilde Keck
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche en Santé 1138, Université Pierre et Marie Curie, Centre de Recherche des Cordeliers, Paris, France
| | - Nicolas Cornière
- Service de Néphrologie, Hôpital Felix Guyon, Centre Hospitalier Universitaire de la Réunion, St Denis, Ile de la Réunion, France
| | - David Böhm
- Institut für Humangenetik, University Hospital Jena, Friedrich-Schiller-Universität, Jena, Germany
| | - Thomas J Jentsch
- Leibniz-Institut für Molekulare Pharmakologie and Max-Delbrück Centrum für Molekulare Medizin, Berlin, Germany
| | - Régine Chambrey
- Institut National de la Santé et de la Recherche Médicale U970, Paris Cardiovascular Research Center, Paris, France.,Faculté de Médecine, Université Paris-Descartes, Paris, France.,Centre National de la Recherche Scientifique, Paris, France; and
| | - Jacques Teulon
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche en Santé 1138, Université Pierre et Marie Curie, Centre de Recherche des Cordeliers, Paris, France;
| | - Christian A Hübner
- Institut für Humangenetik, University Hospital Jena, Friedrich-Schiller-Universität, Jena, Germany
| | - Dominique Eladari
- Institut National de la Santé et de la Recherche Médicale U970, Paris Cardiovascular Research Center, Paris, France; .,Faculté de Médecine, Université Paris-Descartes, Paris, France.,Département de Physiologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Paris, France
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5
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Andrini O, Keck M, Briones R, Lourdel S, Vargas-Poussou R, Teulon J. ClC-K chloride channels: emerging pathophysiology of Bartter syndrome type 3. Am J Physiol Renal Physiol 2015; 308:F1324-34. [DOI: 10.1152/ajprenal.00004.2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/23/2015] [Indexed: 02/08/2023] Open
Abstract
The mutations in the CLCNKB gene encoding the ClC-Kb chloride channel are responsible for Bartter syndrome type 3, one of the four variants of Bartter syndrome in the genetically based nomenclature. All forms of Bartter syndrome are characterized by hypokalemia, metabolic alkalosis, and secondary hyperaldosteronism, but Bartter syndrome type 3 has the most heterogeneous presentation, extending from severe to very mild. A relatively large number of CLCNKB mutations have been reported, including gene deletions and nonsense or missense mutations. However, only 20 CLCNKB mutations have been functionally analyzed, due to technical difficulties regarding ClC-Kb functional expression in heterologous systems. This review provides an overview of recent progress in the functional consequences of CLCNKB mutations on ClC-Kb chloride channel activity. It has been observed that 1) all ClC-Kb mutants have an impaired expression at the membrane; and 2) a minority of the mutants combines reduced membrane expression with altered pH-dependent channel gating. Although further investigation is needed to fully characterize disease pathogenesis, Bartter syndrome type 3 probably belongs to the large family of conformational diseases, in which the mutations destabilize channel structure, inducing ClC-Kb retention in the endoplasmic reticulum and accelerated channel degradation.
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Affiliation(s)
- Olga Andrini
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
| | - Mathilde Keck
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
| | - Rodolfo Briones
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stéphane Lourdel
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
| | - Rosa Vargas-Poussou
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Département de Génétique, Paris, France; and
- Université Paris-Descartes, Faculté de Médecine, Paris, France
| | - Jacques Teulon
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
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6
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Keck M, Andrini O, Lahuna O, Burgos J, Cid LP, Sepúlveda FV, L‘Hoste S, Blanchard A, Vargas-Poussou R, Lourdel S, Teulon J. NovelCLCNKBMutations Causing Bartter Syndrome Affect Channel Surface Expression. Hum Mutat 2013; 34:1269-78. [DOI: 10.1002/humu.22361] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 05/15/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Mathilde Keck
- UPMC Université Paris 06, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
- INSERM, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
| | - Olga Andrini
- UPMC Université Paris 06, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
- INSERM, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
| | - Olivier Lahuna
- UPMC Université Paris 06, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
- INSERM, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
| | - Johanna Burgos
- Centro de Estudios Científicos; Avenida Arturo Prat 514; Valdivia Chile
| | - L. Pablo Cid
- Centro de Estudios Científicos; Avenida Arturo Prat 514; Valdivia Chile
| | | | - Sébastien L‘Hoste
- UPMC Université Paris 06, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
- INSERM, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
| | - Anne Blanchard
- Assistance Publique-Hôpitaux de Paris; Hôpital Européen Georges Pompidou; Centre d'Investigation Clinique; Paris France
- Université Paris-Descartes; Faculté de Médecine; Paris France
| | - Rosa Vargas-Poussou
- Université Paris-Descartes; Faculté de Médecine; Paris France
- Assistance Publique-Hôpitaux de Paris; Hôpital Européen Georges Pompidou; département de génétique; Paris France
| | - Stéphane Lourdel
- UPMC Université Paris 06, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
- INSERM, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
| | - Jacques Teulon
- UPMC Université Paris 06, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
- INSERM, UMR_S 872; Laboratoire de génomique, physiologie et physiopathologie rénales; Paris France
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7
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Wu P, Wang M, Luan H, Li L, Wang L, Wang W, Gu R. Angiotensin II stimulates basolateral 10-pS Cl channels in the thick ascending limb. Hypertension 2013; 61:1211-7. [PMID: 23569086 PMCID: PMC3686115 DOI: 10.1161/hypertensionaha.111.01069] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 03/09/2013] [Indexed: 02/07/2023]
Abstract
Chloride channels in the basolateral membrane play a key role in Cl absorption in the thick ascending limb (TAL). The patch-clamp experiments were performed to test whether angiotensin II (AngII) increases Cl absorption in the TAL by stimulating the basolateral 10-pS Cl channels. AngII (1-100 nmol/L) stimulated the 10-pS Cl channel in the TAL, an effect that was blocked by losartan (angiotension AT1 receptor [AT1R] antagonist) but not by PD123319 (angiotension AT2 receptor [AT2R] antagonist). Inhibition of phospholipase C or protein kinase C also abolished the stimulatory effect of AngII on Cl channels. Moreover, stimulation of protein kinase C with phorbol-12-myristate-13-acetate mimicked the effect of AngII and increased Cl channel activity. However, the stimulatory effect of AngII on Cl channels was absent in the TAL pretreated with diphenyleneiodonium sulfate, an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Moreover, treatment of the TAL with diphenyleneiodonium sulfate also blocked the effect of phorbol-12-myristate-13-acetate on the 10-pS Cl channel. Western blotting demonstrated that incubation of isolated TAL with AngII increased phosphorylation of p47(phox) at Ser(304), suggesting that AngII stimulates the basolateral Cl channels by increasing NADPH oxidase-dependent superoxide generation. This notion was also supported by the observation that H2O2 significantly increased 10-pS Cl channel activity in the TAL. We conclude that stimulation of AT1R increased the basolateral Cl channels by activating the protein kinase C-dependent NADPH oxidase pathway. The stimulatory effect of AngII on the basolateral Cl channel may contribute to AngII-induced increases in NaCl reabsorption in the TAL and AngII-infuse-induced hypertension.
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Affiliation(s)
- Peng Wu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Mingxiao Wang
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Haiyan Luan
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Lili Li
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Lijun Wang
- Department of Physiology, Harbin Medical University, Harbin, China
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Wenhui Wang
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Ruimin Gu
- Department of Pharmacology, Harbin Medical University, Harbin, China
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8
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9
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Gu RM, Yang L, Zhang Y, Wang L, Kong S, Zhang C, Zhai Y, Wang M, Wu P, Liu L, Gu F, Zhang J, Wang WH. CYP-omega-hydroxylation-dependent metabolites of arachidonic acid inhibit the basolateral 10 pS chloride channel in the rat thick ascending limb. Kidney Int 2009; 76:849-56. [PMID: 19641481 PMCID: PMC2861852 DOI: 10.1038/ki.2009.287] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Metabolites of arachidonic acid influence sodium chloride (NaCl) transport in the thick ascending limb. Because a 10 pS Cl channel is the major type of chloride channel in the basolateral membrane of this nephron segment, we explored the effect of arachidonic acid on this channel in cell-attached patches. Addition of 5 micromol arachidonic acid significantly decreased channel activity (a product of channel number and open probability) while linoleic acid had no effect. To determine if this was mediated by acachidonic acid per se or by its metabolites, we measured channel activity in the presence of the cyclooxygenase inhibitor indomethacin, the selective lipoxygenase inhibitor nordihydroguaiaretic acid, and the cytochrome P-450 (CYP)-omega-hydroxylation inhibitor 17-octadecynoic acid. Neither cyclooxygenase nor lipoxygenase inhibition had an effect on basal chloride channel activity; further they failed to abolish the inhibitory effect of arachidonate on the 10 pS channel. However, inhibition of CYP-omega-hydroxylation completely abolished the effect of arachidonic acid. The similarity of the effects of 20-hydroxyeicosatetraenoic acid (20-HETE) and arachidonic acid suggests that the effect of arachidonic acid was mediated by CYP-omega-hydroxylation-dependent metabolites. We conclude that arachidonic acid inhibits the 10 pS chloride channel in the basolateral membrane of the medullary thick ascending limb, an effect mediated by the CYP-omega-hydroxylation-dependent metabolite 20-HETE.
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Affiliation(s)
- Rui-Min Gu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Lei Yang
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Yunhong Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Lijun Wang
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Shumin Kong
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Chengbiao Zhang
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Yuanyuan Zhai
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Mingxiao Wang
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Peng Wu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Liping Liu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Feng Gu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Jiye Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
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10
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Nissant A, Paulais M, Lachheb S, Lourdel S, Teulon J. Similar chloride channels in the connecting tubule and cortical collecting duct of the mouse kidney. Am J Physiol Renal Physiol 2006; 290:F1421-9. [PMID: 16403836 DOI: 10.1152/ajprenal.00274.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Using the patch-clamp technique, we investigated Cl−channels on the basolateral membrane of the connecting tubule (CNT) and cortical collecting duct (CCD). We found a ∼10-pS channel in CNT cell-attached patches. Substitution of sodium gluconate for NaCl in the pipette shifted the reversal potential by +25 mV, whereas N-methyl-d-gluconate chloride had no effect, indicating anion selectivity. On inside-out patches, we determined a selectivity sequence of Cl−> Br−∼ NO3−> F−, which is compatible with that of ClC-K2, a Cl−channel in the distal nephron. In addition, the number of open channels ( NPo) measured in cell-attached patches was significantly increased when Ca2+concentration or pH in the pipette was increased, which is another characteristic of ClC-K. These findings suggest that the basis for this channel is ClC-K2. A similar Cl−channel was found in CCD patches. Because CNT and CCD are heterogeneous tissues, we studied the cellular distribution of the Cl−channel using recording conditions (KCl-rich solution in the pipette) that allowed us to detect simultaneously Cl−channels and inwardly rectifying K+channels. We detected Cl−channels alone in 45% and 42% and K+channels alone in 51% and 58% of CNT and CCD patches, respectively. Cl−and K+channels were recorded simultaneously from two patches (4% of patches) in the CNT and from none of the patches in the CCD. This indicates that Cl−and K+channels are located in different cell types, which we suggest may be the intercalated cells and principal cells, respectively.
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Affiliation(s)
- Antoine Nissant
- Université Pierre et Marie Curie & CNRS, Laboratoire de Physiologie et Génomique des Cellules Rénales, UMR 7134, Institut des Cordeliers, 15 rue de l'Ecole de Médecine, 75270 Paris Cedex 06, France
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11
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Clain J, Lehmann-Che J, Duguépéroux I, Arous N, Girodon E, Legendre M, Goossens M, Edelman A, de Braekeleer M, Teulon J, Fanen P. Misprocessing of theCFTRprotein leads to mild cystic fibrosis phenotype. Hum Mutat 2005; 25:360-71. [PMID: 15776432 DOI: 10.1002/humu.20156] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cystic fibrosis (CF) is mainly caused by mutations that interfere with the biosynthetic folding of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. The aim of this study was to determine the mechanism of dysfunction of a disease-causing mutation associated with variable phenotypes. In order to attain these objectives, we studied the effect of the p.L206W mutation on CFTR protein production and function, and we examined the genotype-phenotype correlation of [p.L206W]+[p.F508del] patients. We showed that p.L206W is a processing (class II) mutation since the CFTR biosynthetic pathway was severely impaired, whereas single-channel measurements indicated ion conductance similar to the wild-type protein. These data raise the larger question of the phenotypic variability of class II mutants, including p.F508del. Since multiple potential partners could modify the processing of the CFTR protein during its course to the cell surface, environmental and other genetic factors might contribute to this variability.
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Affiliation(s)
- Jérôme Clain
- Institut National de la Santé et de la Recherche Médicale (INSERM) U. 468, Hôpital Henri Mondor, Créteil, France
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12
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Barrière H, Tauc M, Poujeol P. Use of knock-out mouse models for the study of renal ion channels. J Membr Biol 2005; 198:113-24. [PMID: 15216413 DOI: 10.1007/s00232-004-0665-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Indexed: 12/30/2022]
Affiliation(s)
- H Barrière
- UMR CNRS 6548, Université de Nice-Sophia Antipolis, 06108 Nice Cedex 2, France
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13
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Hebert SC, Desir G, Giebisch G, Wang W. Molecular diversity and regulation of renal potassium channels. Physiol Rev 2005; 85:319-71. [PMID: 15618483 PMCID: PMC2838721 DOI: 10.1152/physrev.00051.2003] [Citation(s) in RCA: 236] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
K(+) channels are widely distributed in both plant and animal cells where they serve many distinct functions. K(+) channels set the membrane potential, generate electrical signals in excitable cells, and regulate cell volume and cell movement. In renal tubule epithelial cells, K(+) channels are not only involved in basic functions such as the generation of the cell-negative potential and the control of cell volume, but also play a uniquely important role in K(+) secretion. Moreover, K(+) channels participate in the regulation of vascular tone in the glomerular circulation, and they are involved in the mechanisms mediating tubuloglomerular feedback. Significant progress has been made in defining the properties of renal K(+) channels, including their location within tubule cells, their biophysical properties, regulation, and molecular structure. Such progress has been made possible by the application of single-channel analysis and the successful cloning of K(+) channels of renal origin.
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Affiliation(s)
- Steven C Hebert
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520-8026, USA.
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Teulon J, Lourdel S, Nissant A, Paulais M, Guinamard R, Marvao P, Imbert-Teboul M. Exploration of the basolateral chloride channels in the renal tubule using. Nephron Clin Pract 2004; 99:p64-8. [PMID: 15627805 DOI: 10.1159/000082972] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Chloride channels located on the basolateral membrane are known to be involved in chloride absorption in several parts of the renal tubule, and particularly in the thick ascending limb and distal convoluted tubule. The data available suggest that the ClC-K channels play the major role in this process. We provide here a description of the electrophysiological properties of these channels, still very incomplete at this stage, and we attempt to compare ClC-Ks to three chloride channels that we have identified in the basolateral membrane of microdissected fragments of the mouse renal tubule using the patch-clamp technique. Based on anion selectivity and dependence on external pH and calcium shown by the ClC-Ks, we propose candidate ClC-K1 and ClC-K2 in native tissue. We also discuss the possibility that chloride channels that do not belong to the ClC family may also be involved in the absorption of chloride across the cortical thick ascending limb.
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Affiliation(s)
- Jacques Teulon
- UMR 7134 CNRS-UPMC, Centre de Recherches Biomédicales des Cordeliers, Paris, France.
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15
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Sheppard DN. CFTR channel pharmacology: novel pore blockers identified by high-throughput screening. J Gen Physiol 2004; 124:109-13. [PMID: 15277572 PMCID: PMC2229622 DOI: 10.1085/jgp.200409135] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2004] [Accepted: 06/29/2004] [Indexed: 11/20/2022] Open
Affiliation(s)
- David N Sheppard
- Department of Physiology, University of Bristol, School of Medical Sciences, UK
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16
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Kogan I, Ramjeesingh M, Li C, Kidd JF, Wang Y, Leslie EM, Cole SPC, Bear CE. CFTR directly mediates nucleotide-regulated glutathione flux. EMBO J 2003; 22:1981-9. [PMID: 12727866 PMCID: PMC156066 DOI: 10.1093/emboj/cdg194] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Studies have shown that expression of cystic fibrosis transmembrane conductance regulator (CFTR) is associated with enhanced glutathione (GSH) efflux from airway epithelial cells, implicating a role for CFTR in the control of oxidative stress in the airways. To define the mechanism underlying CFTR-associated GSH flux, we studied wild-type and mutant CFTR proteins expressed in Sf9 membranes, as well as purified and reconstituted CFTR. We show that CFTR-expressing membrane vesicles mediate nucleotide-activated GSH flux, which is disrupted in the R347D pore mutant, and in the Walker A K464A and K1250A mutants. Further, we reveal that purified CFTR protein alone directly mediates nucleotide-dependent GSH flux. Interestingly, although ATP supports GSH flux through CFTR, this activity is enhanced in the presence of the non-hydrolyzable ATP analog AMP-PNP. These findings corroborate previous suggestions that CFTR pore properties can vary with the nature of the nucleotide interaction. In conclusion, our data demonstrate that GSH flux is an intrinsic function of CFTR and prompt future examination of the role of this function in airway biology in health and disease.
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Affiliation(s)
- Ilana Kogan
- Hospital for Sick Children, Department of Physiology, University of Toronto, Toronto, Ontario M5G 1X8
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17
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Lourdel S, Paulais M, Marvao P, Nissant A, Teulon J. A chloride channel at the basolateral membrane of the distal-convoluted tubule: a candidate ClC-K channel. J Gen Physiol 2003; 121:287-300. [PMID: 12668733 PMCID: PMC2217373 DOI: 10.1085/jgp.200208737] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The distal-convoluted tubule (DCT) of the kidney absorbs NaCl mainly via an Na+-Cl- cotransporter located at the apical membrane, and Na+, K+ ATPase at the basolateral side. Cl- transport across the basolateral membrane is thought to be conductive, but the corresponding channels have not yet been characterized. In the present study, we investigated Cl- channels on microdissected mouse DCTs using the patch-clamp technique. A channel of approximately 9 pS was found in 50% of cell-attached patches showing anionic selectivity. The NPo in cell-attached patches was not modified when tubules were preincubated in the presence of 10-5 M forskolin, but the channel was inhibited by phorbol ester (10-6 M). In addition, NPo was significantly elevated when the calcium in the pipette was increased from 0 to 5 mM (NPo increased threefold), or pH increased from 6.4 to 8.0 (NPo increased 15-fold). Selectivity experiments conducted on inside-out patches showed that the Na+ to Cl- relative permeability was 0.09, and the anion selectivity sequence Cl(-)--I(-) > Br(-)--NO3(-) > F(-). Intracellular NPPB (10-4 M) and DPC (10-3 M) blocked the channel by 65% and 80%, respectively. The channel was inhibited at acid intracellular pH, but intracellular ATP and PKA had no effect. ClC-K Cl- channels are characterized by their sensitivity to the external calcium and to pH. Since immunohistochemical data indicates that ClC-K2, and perhaps ClC-K1, are present on the DCT basolateral membrane, we suggest that the channel detected in this study may belong to this subfamily of the ClC channel family.
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Affiliation(s)
- Stéphane Lourdel
- Laboratoire de Physiologie, CNRS-FRE 2468, Institut des Cordeliers, 15 rue de l'Ecole de Médecine, 75270 Paris CEDEX 06, France
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18
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Devuyst O, Guggino WB. Chloride channels in the kidney: lessons learned from knockout animals. Am J Physiol Renal Physiol 2002; 283:F1176-91. [PMID: 12426234 DOI: 10.1152/ajprenal.00184.2002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cl- channels are involved in a range of functions, including regulation of cell volume and/or intracellular pH, acidification of intracellular vesicles, and vectorial transport of NaCl across many epithelia. Numerous Cl- channels have been identified in the kidney, based on single-channel properties such as conductance, anion selectivity, gating, and response to inhibitors. The molecular counterpart of many of these Cl- channels is still not known. This review will focus on gene-targeted mouse models disrupting two structural classes of Cl- channels that are relevant for the kidney: the CLC family of voltage-gated Cl- channels and the CFTR. Disruption of several members of the CLC family in the mouse provided useful models for various inherited diseases of the kidney, including Dent's disease and diabetes insipidus. Mice with disrupted CFTR are valuable models for cystic fibrosis (CF), the most common autosomal recessive, lethal disease in Caucasians. Although CFTR is expressed in various nephron segments, there is no overt renal phenotype in CF. Analysis of CF mice has been useful to identify the role and potential interactions of CFTR in the kidney. Furthermore, observations made in CF mice are potentially relevant to all other models of Cl- channel knockouts because they emphasize the importance of alternative Cl- pathways in such models.
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Affiliation(s)
- Olivier Devuyst
- Division of Nephrology, Université Catholique de Louvain Medical School, B-1200 Brussels, Belgium
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Paulais M, Lourdel S, Teulon J. Properties of an inwardly rectifying K(+) channel in the basolateral membrane of mouse TAL. Am J Physiol Renal Physiol 2002; 282:F866-76. [PMID: 11934697 DOI: 10.1152/ajprenal.00238.2001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the properties of K(+) channels in the basolateral membrane of the cortical thick ascending limb (CTAL) using the patch-clamp technique. Approximately 34% of cell-attached patches contained an inwardly rectifying K(+) channel (K(+)-to-Na(+) permeability ratio approximately 22), having an inward conductance (G(in)) of 44 pS and an outward conductance (G(out)) of approximately 10 pS (G(in)/G(out) approximately 4). Channel activity (NP(o)) increased with depolarization. When the cytosolic sides of inside-out patches were exposed to an Mg(2+)-free medium, the channel had a G(in) of 50 pS and was weakly inwardly rectifying (G(in)/G(out) approximately 1). Cytosolic Mg(2+) reduced G(out), yielding a G(in)/G(out) of 3.8 at 1.3 mM Mg(2+). Internal Na(+) also yielded a G(in)/G(out) of 1.6 at 20 mM Na(+). Spermine reduced NP(o) on inside-out membrane patches. Sensitivity to spermine at depolarizing voltages [half-maximal inhibitory concentration (K(i)) = 0.2 microM] was much greater than at hyperpolarizing voltages (K(i) = 26 microM). Half-inactivation by 0.5 microM spermine occurred at a clamp potential of 43 mV, with an effective valence of 1.25. A sigmoid relationship between bath pH and NP(o) of inside-out membrane patches was observed, with a pK of 7.6 and a Hill coefficient of 1.8. Intracellular acidification also reduced the NP(o) of cell-attached patches. This channel is probably a major component of K(+) conductance in the CTAL basolateral membrane.
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Affiliation(s)
- Marc Paulais
- Institut National de la Santé et de la Recherche Médicale U.426, Institut Fédératif de Recherche 02, Faculté de Médecine Xavier Bichat, Université Paris 7, 75018 Paris, France.
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20
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Haskó G, Deitch EA, Németh ZH, Kuhel DG, Szabó C. Inhibitors of ATP-binding cassette transporters suppress interleukin-12 p40 production and major histocompatibility complex II up-regulation in macrophages. J Pharmacol Exp Ther 2002; 301:103-10. [PMID: 11907163 DOI: 10.1124/jpet.301.1.103] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ATP-binding cassette (ABC) transporters are a large family of proteins whose role is to translocate various substances across biological membranes. They include the Tangier disease protein ABC1, sulfonylurea receptors (SUR), multidrug resistance protein (MDR), and cystic fibrosis transmembrane regulator (CFTR). In the current study, we investigated the involvement of ABC transporters in the regulation of lipopolysaccharide (LPS) and/or interferon (IFN)-gamma-induced interleukin (IL)-12 p40 and tumor necrosis factor (TNF)-alpha production, nitric oxide formation, as well as major histocompatibility complex II up-regulation in macrophages. The general ABC transporter inhibitor glibenclamide suppressed both IL-12 p40 and nitric oxide production. However, glibenclamide failed to affect the production of TNF-alpha. The selective ABC1 inhibitors 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid and sulfobromophthalein mimicked the suppressive effect of glibenclamide on IL-12 p40 production. On the other hand, both the MDR inhibitor verapamil and CFTR blocker 2,2'-iminodibenzoic acid failed to suppress the production of IL-12 p40. Furthermore, selective inhibitors and activators of SURs were without effect. In agreement with the pharmacological data, macrophages expressed mRNA for ABC1, but not SURs or CFTR. Intracellular levels of IL-12 p40 were decreased by glibenclamide, suggesting that glibenclamide does not affect IL-12 p40 secretion. The effect of glibenclamide did not involve an interference with the activation of the p38 and p42/44 mitogen-activated protein kinases or c-Jun kinase. Glibenclamide also suppressed IFN-gamma-induced up-regulation of major histocompatibility complex II. Taken together, our results indicate that ABC proteins regulate LPS and/or IFN-gamma-induced macrophage activation.
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Affiliation(s)
- György Haskó
- Department of Surgery, University of Medicine and Dentistry-New Jersey Medical School, Newark, New Jersey 07103, USA.
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21
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Bens M, Duong Van Huyen JP, Cluzeaud F, Teulon J, Vandewalle A. CFTR disruption impairs cAMP-dependent Cl(-) secretion in primary cultures of mouse cortical collecting ducts. Am J Physiol Renal Physiol 2001; 281:F434-42. [PMID: 11502593 DOI: 10.1152/ajprenal.2001.281.3.f434] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The role of the cystic fibrosis transmembrane conductance regulator (CFTR) in the renal cortical collecting duct (CCD) has not yet been fully elucidated. Here, we investigated the effects of deamino-8-D-arginine vasopressin (dDAVP) and isoproterenol (ISO) on NaCl transport in primary cultured CCDs microdissected from normal [CFTR(+/+)] and CFTR-knockout [CFTR(-/-)] mice. dDAVP stimulated the benzamyl amiloride (BAm)-sensitive transport of Na(+) assessed by the short-circuit current (I(sc)) method in both CFTR(+/+) and CFTR(-/-) CCDs to a very similar degree. Apical addition of 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) or glibenclamide partially inhibited the rise in I(sc) induced by dDAVP and ISO in BAm-treated CFTR(+/+) CCDs, whereas dDAVP, ISO, and NPPB did not alter I(sc) in BAm-treated CFTR(-/-) CCDs. dDAVP stimulated the apical-to-basal flux and, to a lesser extent, the basal-to-apical flux of (36)Cl(-) in CFTR(+/+) CCDs. dDAVP also increased the apical-to-basal (36)Cl(-) flux in CFTR(-/-) CCDs but not the basal-to-apical (36)Cl(-) flux. These results demonstrate that CFTR mediates the cAMP-stimulated component of secreted Cl(-) in mouse CCD.
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Affiliation(s)
- M Bens
- Institut National de la Santé et de la Recherche Médicale, Unité 478, Faculté de Médecine Xavier Bichat, 75870 Paris, France
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22
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Kibble JD, Balloch KJ, Neal AM, Hill C, White S, Robson L, Green R, Taylor CJ. Renal proximal tubule function is preserved in Cftr(tm2cam) deltaF508 cystic fibrosis mice. J Physiol 2001; 532:449-57. [PMID: 11306663 PMCID: PMC2278541 DOI: 10.1111/j.1469-7793.2001.0449f.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
1. Changes in proximal tubule function have been reported in cystic fibrosis patients. The aim of this study was to investigate proximal tubule function in the Cftr(tm2cam)deltaF508 cystic fibrosis (CF) mouse model. A range of techniques were used including renal clearance studies, in situ microperfusion, RT-PCR and whole-cell patch clamping. 2. Renal Na(+) clearance was similar in wild-type (1.4 +/- 0.3 microl min(-1), number of animals, N = 12) and CF mice (1.6 +/- 0.4 microl min(-1), N = 7) under control conditions. Acute extracellular volume expansion resulted in significant natriuresis in wild-type (7.0 +/- 0.8 microl min(-1), N = 8) and CF mice (9.3 +/- 1.4 microl min(-1), N = 9); no difference between genotypes was observed. 3. In situ microperfusion revealed that fluid absorptive rate (Jv) was similar under control conditions between wild-type (2.2 +/- 0.4 nl mm(-1) min(-1), n = 10) and CF mice (1.9 +/- 0.3 nl mm(-1) min(-1), n = 11). Addition of a forskolin-dibutyryl cAMP (db-cAMP) cocktail to the perfusate caused no significant change in Jv in either wild-type (2.6 +/- 0.7 nl mm(-1) min(-1), n = 10) or Cftr(tm2cam)deltaF508 mice (2.0 +/- 0.5 nl mm(-1) min(-1), n = 10). 4. CFTR expression was confirmed in samples of outer cortex using RT-PCR. However, no evidence for functional CFTR was obtained when outer cortical cells were stimulated with protein kinase A or forskolin-db-cAMP using whole-cell patch clamping. 5. In conclusion, no functional deficit in proximal tubule function was found in Cftr(tm2cam)deltaF508 mice. This may be a consequence of a lack of whole-cell cAMP-dependent Cl(-) conductance in mouse proximal tubule cells.
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Affiliation(s)
- J D Kibble
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK.
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23
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Duong Van Huyen JP, Bens M, Teulon J, Vandewalle A. Vasopressin-stimulated chloride transport in transimmortalized mouse cell lines derived from the distal convoluted tubule and cortical and inner medullary collecting ducts. Nephrol Dial Transplant 2001; 16:238-45. [PMID: 11158395 DOI: 10.1093/ndt/16.2.238] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The fine control of NaCl absorption takes place in the distal parts of the renal tubule, but the regulation of Cl(-) transport in this region has not been fully elucidated. We have analysed the effects of dD-arginine vasopressin (dDAVP) on Cl(-) fluxes in cultured mouse distal convoluted tubule (mpkDCT), cortical collecting duct (mpkCCD) and inner medullary collecting duct (mpkIMCD) cell lines. METHODS RT-PCR and Western blotting were used to detect the amiloride-sensitive sodium channel (ENaC) and cystic fibrosis transmembrane conductance regulator (CFTR) mRNAs and protein in cultured mpkDCT, mpkCCD and mpkIMCD cells. Cl(-) fluxes were analysed by measuring the short-circuit current (I(sc)) and bidirectional (36)Cl(-) fluxes on confluent cells grown on filters. RESULTS All three cell lines expressed ENaC and CFTR and had I(sc) stimulated by dDAVP. The rise in I(sc) caused by dDAVP (10(-8) M) was inhibited by amiloride, and to a lesser extent by 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) in all three cell lines. The dDAVP-dependent I(sc) measured under apical Na(+)-free condition was reduced by Cl(-) channel blockers with a profile (NPPB>glibenclamide>DIDS), similar to that for rat CFTR. dDAVP stimulated the apical-to-basal (36)Cl(-) flux and to a lesser extent the basal-to-apical (36)Cl(-) flux under open-circuit condition in all three cultured cell lines. Adding NPPB to the apical side reduced the basal-to-apical (36)Cl(-) flux but not the opposite (36)Cl(-) flux from dDAVP-treated cells. CONCLUSION These results indicate that dDAVP stimulates the bi-directional flux of Cl(-), resulting in net Cl(-)absorption, in these cultured mouse distal and collecting duct cells. I(sc) experiments also suggest the presence of a minor component of electrogenic Cl(-) secretion, possibly mediated by CFTR.
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Affiliation(s)
- J P Duong Van Huyen
- Institut National de la Santé et de la Recherche Médicale, Unité 478, Institut Fédératif de Recherche 02, Faculté de Médecine Xavier Bichat, Paris, France
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Morales MM, Falkenstein D, Lopes AG. The cystic fibrosis transmembrane regulator (CFTR) in the kidney. AN ACAD BRAS CIENC 2000; 72:399-406. [PMID: 11028104 DOI: 10.1590/s0001-37652000000300013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cystic fibrosis transmembrane regulator (CFTR) is a Cl - channel. Mutations of this transporter lead to a defect of chloride secretion by epithelial cells causing the Cystic Fibrosis disease (CF). In spite of the high expression of CFTR in the kidney, patients with CF do not show major renal dysfunction, but it is known that both the urinary excretion of drugs and the renal capacity to concentrate and dilute urine is deficient. CFTR mRNA is expressed in all nephron segments and its protein is involved with chloride secretion in the distal tubule, and the principal cells of the cortical (CCD) and medullary (IMCD) collecting ducts. Several studies have demonstrated that CFTR does not only transport Cl - but also secretes ATP and, thus, controls other conductances such as Na+ (ENaC) and K+ (ROMK2) channels, especially in CCD. In the polycystic kidney the secretion of chloride through CFTR contributes to the cyst enlargement. This review is focused on the role of CFTR in the kidney and the implications of extracellular volume regulators, such as hormones, on its function and expression.
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Affiliation(s)
- M M Morales
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21949-900, Brazil
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