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Meindl K, Issler N, Afonso S, Cebrian-Serrano A, Müller K, Sterner C, Othmen H, Tegtmeier I, Witzgall R, Klootwijk E, Davies B, Kleta R, Warth R. A missense mutation in Ehd1 associated with defective spermatogenesis and male infertility. Front Cell Dev Biol 2023; 11:1240558. [PMID: 37900275 PMCID: PMC10600459 DOI: 10.3389/fcell.2023.1240558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 09/28/2023] [Indexed: 10/31/2023] Open
Abstract
Normal function of the C-terminal Eps15 homology domain-containing protein 1 (EHD1) has previously been associated with endocytic vesicle trafficking, shaping of intracellular membranes, and ciliogenesis. We recently identified an autosomal recessive missense mutation c.1192C>T (p.R398W) of EHD1 in patients who had low molecular weight proteinuria (0.7-2.1 g/d) and high-frequency hearing loss. It was already known from Ehd1 knockout mice that inactivation of Ehd1 can lead to male infertility. However, the exact role of the EHD1 protein and its p.R398W mutant during spermatogenesis remained still unclear. Here, we report the testicular phenotype of a knockin mouse model carrying the p.R398W mutation in the EHD1 protein. Male homozygous knockin mice were infertile, whereas the mutation had no effect on female fertility. Testes and epididymes were significantly reduced in size and weight. The testicular epithelium appeared profoundly damaged and had a disorganized architecture. The composition of developing cell types was altered. Malformed acrosomes covered underdeveloped and misshaped sperm heads. In the sperm tail, midpieces were largely missing indicating disturbed assembly of the sperm tail. Defective structures, i.e., nuclei, acrosomes, and sperm tail midpieces, were observed in large vacuoles scattered throughout the epithelium. Interestingly, cilia formation itself did not appear to be affected, as the axoneme and other parts of the sperm tails except the midpieces appeared to be intact. In wildtype mice, EHD1 co-localized with acrosomal granules on round spermatids, suggesting a role of the EHD1 protein during acrosomal development. Wildtype EHD1 also co-localized with the VPS35 component of the retromer complex, whereas the p.R398W mutant did not. The testicular pathologies appeared very early during the first spermatogenic wave in young mice (starting at 14 dpp) and tubular destruction worsened with age. Taken together, EHD1 plays an important and probably multifaceted role in spermatogenesis in mice. Therefore, EHD1 may also be a hitherto underestimated infertility gene in humans.
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Affiliation(s)
- Katrin Meindl
- Medical Cell Biology, University Regensburg, Regensburg, Germany
| | - Naomi Issler
- Department of Renal Medicine, University College London, London, United Kingdom
- Pediatric Nephrology Unit and Research Lab, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sara Afonso
- Medical Cell Biology, University Regensburg, Regensburg, Germany
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Alberto Cebrian-Serrano
- Wellcome Centre for Human Genetics, University Oxford, Oxford, United Kingdom
- Helmholtz Zentrum München, Institute of Diabetes and Obesity, Munich, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Karin Müller
- Leibniz Institute for Zoo- und Wildlife Research, Berlin, Germany
| | | | - Helga Othmen
- Medical Cell Biology, University Regensburg, Regensburg, Germany
- Molecular and Cellular Anatomy, University Regensburg, Regensburg, Germany
| | - Ines Tegtmeier
- Medical Cell Biology, University Regensburg, Regensburg, Germany
| | - Ralph Witzgall
- Molecular and Cellular Anatomy, University Regensburg, Regensburg, Germany
| | - Enriko Klootwijk
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Benjamin Davies
- Wellcome Centre for Human Genetics, University Oxford, Oxford, United Kingdom
- Genetic Modification Service, The Francis Crick Institute, London, United Kingdom
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Richard Warth
- Medical Cell Biology, University Regensburg, Regensburg, Germany
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Rege J, Bandulik S, Nanba K, Kosmann C, Blinder AR, Plain A, Vats P, Kumar-Sinha C, Lerario AM, Else T, Yamazaki Y, Satoh F, Sasano H, Giordano TJ, Williams TA, Reincke M, Turcu AF, Udager AM, Warth R, Rainey WE. Somatic SLC30A1 mutations altering zinc transporter ZnT1 cause aldosterone-producing adenomas and primary aldosteronism. Nat Genet 2023; 55:1623-1631. [PMID: 37709865 DOI: 10.1038/s41588-023-01498-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/08/2023] [Indexed: 09/16/2023]
Abstract
Primary aldosteronism (PA) is the most common form of endocrine hypertension and is characterized by inappropriately elevated aldosterone production via a renin-independent mechanism. Driver somatic mutations for aldosterone excess have been found in approximately 90% of aldosterone-producing adenomas (APAs). Other causes of lateralized adrenal PA include aldosterone-producing nodules (APNs). Using next-generation sequencing, we identified recurrent in-frame deletions in SLC30A1 in four APAs and one APN (p.L51_A57del, n = 3; p.L49_L55del, n = 2). SLC30A1 encodes the ubiquitous zinc efflux transporter ZnT1 (zinc transporter 1). The identified SLC30A1 variants are situated close to the zinc-binding site (His43 and Asp47) in transmembrane domain II and probably cause abnormal ion transport. Cases of PA with SLC30A1 mutations showed male dominance and demonstrated increased aldosterone and 18-oxocortisol concentrations. Functional studies of the SLC30A151_57del variant in a doxycycline-inducible adrenal cell system revealed pathological Na+ influx. An aberrant Na+ current led to depolarization of the resting membrane potential and, thus, to the opening of voltage-gated calcium (Ca2+) channels. This resulted in an increase in cytosolic Ca2+ activity, which stimulated CYP11B2 mRNA expression and aldosterone production. Collectively, these data implicate zinc transporter alterations as a dominant driver of aldosterone excess in PA.
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Affiliation(s)
- Juilee Rege
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Kazutaka Nanba
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Endocrinology and Metabolism, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
| | - Carla Kosmann
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Amy R Blinder
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Allein Plain
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Pankaj Vats
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Chandan Kumar-Sinha
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Antonio M Lerario
- Division of Metabolism, Endocrine, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Tobias Else
- Division of Metabolism, Endocrine, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Yuto Yamazaki
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Fumitoshi Satoh
- Division of Clinical Hypertension, Endocrinology and Metabolism, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hironobu Sasano
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | - Tracy Ann Williams
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Ludwig Maximilian University of Munich, Munich, Germany
- Division of Internal Medicine and Hypertension, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Martin Reincke
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Ludwig Maximilian University of Munich, Munich, Germany
| | - Adina F Turcu
- Division of Metabolism, Endocrine, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Aaron M Udager
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - William E Rainey
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
- Division of Metabolism, Endocrine, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
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Stanzick KJ, Stark KJ, Gorski M, Schödel J, Krüger R, Kronenberg F, Warth R, Heid IM, Winkler TW. KidneyGPS: a user-friendly web application to help prioritize kidney function genes and variants based on evidence from genome-wide association studies. BMC Bioinformatics 2023; 24:355. [PMID: 37735349 PMCID: PMC10512588 DOI: 10.1186/s12859-023-05472-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 09/08/2023] [Indexed: 09/23/2023] Open
Abstract
BACKGROUND Genome-wide association studies (GWAS) have identified hundreds of genetic loci associated with kidney function. By combining these findings with post-GWAS information (e.g., statistical fine-mapping to identify independent association signals and to narrow down signals to causal variants; or different sources of annotation data), new hypotheses regarding physiology and disease aetiology can be obtained. These hypotheses need to be tested in laboratory experiments, for example, to identify new therapeutic targets. For this purpose, the evidence obtained from GWAS and post-GWAS analyses must be processed and presented in a way that they are easily accessible to kidney researchers without specific GWAS expertise. MAIN: Here we present KidneyGPS, a user-friendly web-application that combines genetic variant association for estimated glomerular filtration rate (eGFR) from the Chronic Kidney Disease Genetics consortium with annotation of (i) genetic variants with functional or regulatory effects ("SNP-to-gene" mapping), (ii) genes with kidney phenotypes in mice or human ("gene-to-phenotype"), and (iii) drugability of genes (to support re-purposing). KidneyGPS adopts a comprehensive approach summarizing evidence for all 5906 genes in the 424 GWAS loci for eGFR identified previously and the 35,885 variants in the 99% credible sets of 594 independent signals. KidneyGPS enables user-friendly access to the abundance of information by search functions for genes, variants, and regions. KidneyGPS also provides a function ("GPS tab") to generate lists of genes with specific characteristics thus enabling customizable Gene Prioritisation (GPS). These specific characteristics can be as broad as any gene in the 424 loci with a known kidney phenotype in mice or human; or they can be highly focussed on genes mapping to genetic variants or signals with particularly with high statistical support. KidneyGPS is implemented with RShiny in a modularized fashion to facilitate update of input data ( https://kidneygps.ur.de/gps/ ). CONCLUSION With the focus on kidney function related evidence, KidneyGPS fills a gap between large general platforms for accessing GWAS and post-GWAS results and the specific needs of the kidney research community. This makes KidneyGPS an important platform for kidney researchers to help translate in silico research results into in vitro or in vivo research.
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Affiliation(s)
- Kira J Stanzick
- Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany
| | - Klaus J Stark
- Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany
| | - Mathias Gorski
- Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany
| | - Johannes Schödel
- Department of Nephrology and Hypertension, Friedrich-Alexander Universität Erlangen-Nürnberg, and Uniklinikum Erlangen, Erlangen, Germany
| | - René Krüger
- Department of Nephrology and Hypertension, Friedrich-Alexander Universität Erlangen-Nürnberg, and Uniklinikum Erlangen, Erlangen, Germany
| | - Florian Kronenberg
- Department of Genetics, Institute of Genetic Epidemiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Iris M Heid
- Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany.
| | - Thomas W Winkler
- Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany.
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Issler N, Afonso S, Weissman I, Jordan K, Cebrian-Serrano A, Meindl K, Dahlke E, Tziridis K, Yan G, Robles-López JM, Tabernero L, Patel V, Kesselheim A, Klootwijk ED, Stanescu HC, Dumitriu S, Iancu D, Tekman M, Mozere M, Jaureguiberry G, Outtandy P, Russell C, Forst AL, Sterner C, Heinl ES, Othmen H, Tegtmeier I, Reichold M, Schiessl IM, Limm K, Oefner P, Witzgall R, Fu L, Theilig F, Schilling A, Shuster Biton E, Kalfon L, Fedida A, Arnon-Sheleg E, Ben Izhak O, Magen D, Anikster Y, Schulze H, Ziegler C, Lowe M, Davies B, Böckenhauer D, Kleta R, Falik Zaccai TC, Warth R. A Founder Mutation in EHD1 Presents with Tubular Proteinuria and Deafness. J Am Soc Nephrol 2022; 33:732-745. [PMID: 35149593 PMCID: PMC8970462 DOI: 10.1681/asn.2021101312] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/17/2021] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND The endocytic reabsorption of proteins in the proximal tubule requires a complex machinery and defects can lead to tubular proteinuria. The precise mechanisms of endocytosis and processing of receptors and cargo are incompletely understood. EHD1 belongs to a family of proteins presumably involved in the scission of intracellular vesicles and in ciliogenesis. However, the relevance of EHD1 in human tissues, in particular in the kidney, was unknown. METHODS Genetic techniques were used in patients with tubular proteinuria and deafness to identify the disease-causing gene. Diagnostic and functional studies were performed in patients and disease models to investigate the pathophysiology. RESULTS We identified six individuals (5-33 years) with proteinuria and a high-frequency hearing deficit associated with the homozygous missense variant c.1192C>T (p.R398W) in EHD1. Proteinuria (0.7-2.1 g/d) consisted predominantly of low molecular weight proteins, reflecting impaired renal proximal tubular endocytosis of filtered proteins. Ehd1 knockout and Ehd1R398W/R398W knockin mice also showed a high-frequency hearing deficit and impaired receptor-mediated endocytosis in proximal tubules, and a zebrafish model showed impaired ability to reabsorb low molecular weight dextran. Interestingly, ciliogenesis appeared unaffected in patients and mouse models. In silico structural analysis predicted a destabilizing effect of the R398W variant and possible inference with nucleotide binding leading to impaired EHD1 oligomerization and membrane remodeling ability. CONCLUSIONS A homozygous missense variant of EHD1 causes a previously unrecognized autosomal recessive disorder characterized by sensorineural deafness and tubular proteinuria. Recessive EHD1 variants should be considered in individuals with hearing impairment, especially if tubular proteinuria is noted.
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Affiliation(s)
- Naomi Issler
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Sara Afonso
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Irith Weissman
- Pediatric Nephrology, Galilee Medical Center, Nahraia, Israel
| | - Katrin Jordan
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | | | - Katrin Meindl
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Eileen Dahlke
- Institute of Anatomy, University of Kiel, Kiel, Germany
| | - Konstantin Tziridis
- Ear, Nose, and Throat Clinic, University Hospital Erlangen, Erlangen, Germany
| | - Guanhua Yan
- Division of Molecular and Cellular Function, University of Manchester, United Kingdom
| | - José M. Robles-López
- Division of Molecular and Cellular Function, University of Manchester, United Kingdom
| | - Lydia Tabernero
- Division of Molecular and Cellular Function, University of Manchester, United Kingdom
| | - Vaksha Patel
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Anne Kesselheim
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Enriko D. Klootwijk
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Horia C. Stanescu
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Simona Dumitriu
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Daniela Iancu
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Mehmet Tekman
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Monika Mozere
- Department of Renal Medicine, University College London, London, United Kingdom
| | | | - Priya Outtandy
- Department of Renal Medicine, University College London, London, United Kingdom
| | | | - Anna-Lena Forst
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | | | | | - Helga Othmen
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Ines Tegtmeier
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Markus Reichold
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | | | - Katharina Limm
- Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
| | - Peter Oefner
- Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
| | - Ralph Witzgall
- Molecular and Cellular Anatomy, University of Regensburg, Regensburg, Germany
| | - Lifei Fu
- Structural Biology, University of Regensburg, Regensburg, Germany
| | | | - Achim Schilling
- Ear, Nose, and Throat Clinic, University Hospital Erlangen, Erlangen, Germany
| | | | - Limor Kalfon
- Institute of Human Genetics, Galilee Medical Center, Nahraia, Israel
| | - Ayalla Fedida
- Institute of Human Genetics, Galilee Medical Center, Nahraia, Israel
| | | | - Ofer Ben Izhak
- Department of Pathology, Rambam Health Care Campus, Technion Faculty of Medicine, Haifa, Israel
| | - Daniella Magen
- Pediatric Nephrology Institute, Rambam Health Care Campus, Technion Faculty of Medicine, Haifa, Israel
| | | | - Holger Schulze
- Ear, Nose, and Throat Clinic, University Hospital Erlangen, Erlangen, Germany
| | | | - Martin Lowe
- Division of Molecular and Cellular Function, University of Manchester, United Kingdom
| | - Benjamin Davies
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Detlef Böckenhauer
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Tzipora C. Falik Zaccai
- The Azrieli Faculty of Medicine, Bar Ilan, Safed, Israel
- Institute of Human Genetics, Galilee Medical Center, Nahraia, Israel
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
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Lo J, Forst AL, Warth R, Zdebik AA. EAST/SeSAME Syndrome and Beyond: The Spectrum of Kir4.1- and Kir5.1-Associated Channelopathies. Front Physiol 2022; 13:852674. [PMID: 35370765 PMCID: PMC8965613 DOI: 10.3389/fphys.2022.852674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/08/2022] [Indexed: 12/13/2022] Open
Abstract
In 2009, two groups independently linked human mutations in the inwardly rectifying K+ channel Kir4.1 (gene name KCNJ10) to a syndrome affecting the central nervous system (CNS), hearing, and renal tubular salt reabsorption. The autosomal recessive syndrome has been named EAST (epilepsy, ataxia, sensorineural deafness, and renal tubulopathy) or SeSAME syndrome (seizures, sensorineural deafness, ataxia, intellectual disability, and electrolyte imbalance), accordingly. Renal dysfunction in EAST/SeSAME patients results in loss of Na+, K+, and Mg2+ with urine, activation of the renin-angiotensin-aldosterone system, and hypokalemic metabolic alkalosis. Kir4.1 is highly expressed in affected organs: the CNS, inner ear, and kidney. In the kidney, it mostly forms heteromeric channels with Kir5.1 (KCNJ16). Biallelic loss-of-function mutations of Kir5.1 can also have disease significance, but the clinical symptoms differ substantially from those of EAST/SeSAME syndrome: although sensorineural hearing loss and hypokalemia are replicated, there is no alkalosis, but rather acidosis of variable severity; in contrast to EAST/SeSAME syndrome, the CNS is unaffected. This review provides a framework for understanding some of these differences and will guide the reader through the growing literature on Kir4.1 and Kir5.1, discussing the complex disease mechanisms and the variable expression of disease symptoms from a molecular and systems physiology perspective. Knowledge of the pathophysiology of these diseases and their multifaceted clinical spectrum is an important prerequisite for making the correct diagnosis and forms the basis for personalized therapies.
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Affiliation(s)
- Jacky Lo
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Anna-Lena Forst
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Anselm A. Zdebik
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- Centre for Nephrology, University College London, London, United Kingdom
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6
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Neubauer J, Forst AL, Warth R, Both CP, Haas C, Thomas J. Genetic variants in eleven central and peripheral chemoreceptor genes in sudden infant death syndrome. Pediatr Res 2022; 92:1026-1033. [PMID: 35102300 PMCID: PMC9586864 DOI: 10.1038/s41390-021-01899-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 07/14/2021] [Accepted: 08/16/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Sudden infant death syndrome (SIDS) is still one of the leading causes of postnatal infant death in developed countries. The occurrence of SIDS is described by a multifactorial etiology that involves the respiratory control system including chemoreception. It is still unclear whether genetic variants in genes involved in respiratory chemoreception might play a role in SIDS. METHODS The exome data of 155 SIDS cases were screened for variants within 11 genes described in chemoreception. Pathogenicity of variants was assigned based on the assessment of variant types and in silico protein predictions according to the current recommendations of the American College of Medical Genetics and Genomics. RESULTS Potential pathogenic variants in genes encoding proteins involved in respiratory chemoreception could be identified in 5 (3%) SIDS cases. Two of the variants (R137S/A188S) were found in the KNCJ16 gene, which encodes for the potassium channel Kir5.1, presumably involved in central chemoreception. Electrophysiologic analysis of these KCNJ16 variants revealed a loss-of-function for the R137S variant but no obvious impairment for the A188S variant. CONCLUSIONS Genetic variants in genes involved in respiratory chemoreception may be a risk factor in a fraction of SIDS cases and may thereby contribute to the multifactorial etiology of SIDS. IMPACT What is the key message of your article? Gene variants encoding proteins involved in respiratory chemoreception may play a role in a minority of SIDS cases. What does it add to the existing literature? Although impaired respiratory chemoreception has been suggested as an important risk factor for SIDS, genetic variants in single genes seem to play a minor role. What is the impact? This study supports previous findings, which indicate that genetic variants in single genes involved in respiratory control do not have a dominant role in SIDS.
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Affiliation(s)
- Jacqueline Neubauer
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Anna-Lena Forst
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Christian Peter Both
- grid.412341.10000 0001 0726 4330Department of Anesthesiology, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Cordula Haas
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Jörg Thomas
- Department of Anesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.
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7
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Forst AL, Reichold M, Kleta R, Warth R. Distinct Mitochondrial Pathologies Caused by Mutations of the Proximal Tubular Enzymes EHHADH and GATM. Front Physiol 2021; 12:715485. [PMID: 34349672 PMCID: PMC8326905 DOI: 10.3389/fphys.2021.715485] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 06/28/2021] [Indexed: 12/18/2022] Open
Abstract
The mitochondria of the proximal tubule are essential for providing energy in this nephron segment, whose ATP generation is almost exclusively oxygen dependent. In addition, mitochondria are involved in a variety of metabolic processes and complex signaling networks. Proximal tubular mitochondrial dysfunction can therefore affect renal function in very different ways. Two autosomal dominantly inherited forms of renal Fanconi syndrome illustrate how multifaceted mitochondrial pathology can be: Mutation of EHHADH, an enzyme in fatty acid metabolism, results in decreased ATP synthesis and a consecutive transport defect. In contrast, mutations of GATM, an enzyme in the creatine biosynthetic pathway, leave ATP synthesis unaffected but do lead to mitochondrial protein aggregates, inflammasome activation, and renal fibrosis with progressive renal failure. In this review article, the distinct pathophysiological mechanisms of these two diseases are presented, which are examples of the spectrum of proximal tubular mitochondrial diseases.
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Affiliation(s)
- Anna-Lena Forst
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Markus Reichold
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Robert Kleta
- Centre for Nephrology, University College London, London, United Kingdom
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
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8
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Schlingmann KP, Renigunta A, Hoorn EJ, Forst AL, Renigunta V, Atanasov V, Mahendran S, Barakat TS, Gillion V, Godefroid N, Brooks AS, Lugtenberg D, Lake J, Debaix H, Rudin C, Knebelmann B, Tellier S, Rousset-Rouvière C, Viering D, de Baaij JHF, Weber S, Palygin O, Staruschenko A, Kleta R, Houillier P, Bockenhauer D, Devuyst O, Vargas-Poussou R, Warth R, Zdebik AA, Konrad M. Defects in KCNJ16 Cause a Novel Tubulopathy with Hypokalemia, Salt Wasting, Disturbed Acid-Base Homeostasis, and Sensorineural Deafness. J Am Soc Nephrol 2021; 32:1498-1512. [PMID: 33811157 PMCID: PMC8259640 DOI: 10.1681/asn.2020111587] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/04/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The transepithelial transport of electrolytes, solutes, and water in the kidney is a well-orchestrated process involving numerous membrane transport systems. Basolateral potassium channels in tubular cells not only mediate potassium recycling for proper Na+,K+-ATPase function but are also involved in potassium and pH sensing. Genetic defects in KCNJ10 cause EAST/SeSAME syndrome, characterized by renal salt wasting with hypokalemic alkalosis associated with epilepsy, ataxia, and sensorineural deafness. METHODS A candidate gene approach and whole-exome sequencing determined the underlying genetic defect in eight patients with a novel disease phenotype comprising a hypokalemic tubulopathy with renal salt wasting, disturbed acid-base homeostasis, and sensorineural deafness. Electrophysiologic studies and surface expression experiments investigated the functional consequences of newly identified gene variants. RESULTS We identified mutations in the KCNJ16 gene encoding KCNJ16, which along with KCNJ15 and KCNJ10, constitutes the major basolateral potassium channel of the proximal and distal tubules, respectively. Coexpression of mutant KCNJ16 together with KCNJ15 or KCNJ10 in Xenopus oocytes significantly reduced currents. CONCLUSIONS Biallelic variants in KCNJ16 were identified in patients with a novel disease phenotype comprising a variable proximal and distal tubulopathy associated with deafness. Variants affect the function of heteromeric potassium channels, disturbing proximal tubular bicarbonate handling as well as distal tubular salt reabsorption.
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Affiliation(s)
- Karl P. Schlingmann
- Department of General Pediatrics, Pediatric Nephrology, University Children’s Hospital, Munster, Germany
| | - Aparna Renigunta
- Department of Pediatric Nephrology, Marburg Kidney Research Center, Philipps University, Marburg, Germany
| | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Anna-Lena Forst
- Department of Physiology, Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Vijay Renigunta
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University, Marburg, Germany
| | - Velko Atanasov
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Sinthura Mahendran
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | | | - Valentine Gillion
- Division of Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium
| | - Nathalie Godefroid
- Division of Pediatric Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium
| | - Alice S. Brooks
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Dorien Lugtenberg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jennifer Lake
- Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Huguette Debaix
- Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Christoph Rudin
- Department of Pediatric Nephrology, University Children’s Hospital, Basel, Switzerland
| | - Bertrand Knebelmann
- Department of Nephrology-Transplantation, Assistance Publique Hôpitaux de Paris, Hôpital Necker, Paris, France,Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France
| | - Stephanie Tellier
- Department of Pediatric Nephrology, and Rheumatology, French Reference Center of Rare Renal Diseases (SORARE), CHU Toulouse, Toulouse, France,Division of Rheumatology, Department of Pediatrics, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Caroline Rousset-Rouvière
- Department of Multidisciplinary Pediatrics, Pediatric Nephrology Unit, La Timone, University Hospital of Marseille, Marseille, France
| | - Daan Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H. F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stefanie Weber
- Department of Pediatric Nephrology, Marburg Kidney Research Center, Philipps University, Marburg, Germany
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin,Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, United Kingdom
| | - Pascal Houillier
- Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France,Department of Physiology, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France,Department of Renal Physiology, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, Paris, France
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, United Kingdom
| | - Olivier Devuyst
- Division of Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium,Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France,Department of Renal Physiology, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, Paris, France,Department of Genetics, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France
| | - Richard Warth
- Department of Physiology, Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Anselm A. Zdebik
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom,Department of Renal Medicine, University College London, London, United Kingdom
| | - Martin Konrad
- Department of General Pediatrics, Pediatric Nephrology, University Children’s Hospital, Munster, Germany
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9
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Gürtler F, Jordan K, Tegtmeier I, Herold J, Stindl J, Warth R, Bandulik S. Cellular Pathophysiology of Mutant Voltage-Dependent Ca2+ Channel CACNA1H in Primary Aldosteronism. Endocrinology 2020; 161:5891807. [PMID: 32785697 DOI: 10.1210/endocr/bqaa135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 08/04/2020] [Indexed: 12/29/2022]
Abstract
The physiological stimulation of aldosterone production in adrenocortical glomerulosa cells by angiotensin II and high plasma K+ depends on the depolarization of the cell membrane potential and the subsequent Ca2+ influx via voltage-activated Ca2+ channels. Germline mutations of the low-voltage activated T-type Ca2+ channel CACNA1H (Cav3.2) have been found in patients with primary aldosteronism. Here, we investigated the electrophysiology and Ca2+ signaling of adrenal NCI-H295R cells overexpressing CACNA1H wildtype and mutant M1549V in order to understand how mutant CACNA1H alters adrenal cell function. Whole-cell patch-clamp measurements revealed a strong activation of mutant CACNA1H at the resting membrane potential of adrenal cells. Both the expression of wildtype and mutant CACNA1H led to a depolarized membrane potential. In addition, cells expressing mutant CACNA1H developed pronounced action potential-like membrane voltage oscillations. Ca2+ measurements showed an increased basal Ca2+ activity, an altered K+ sensitivity, and abnormal oscillating Ca2+ changes in cells with mutant CACNA1H. In addition, removal of extracellular Na+ reduced CACNA1H current, voltage oscillations, and Ca2+ levels in mutant cells, suggesting a role of the partial Na+ conductance of CACNA1H in cellular pathology. In conclusion, the pathogenesis of stimulus-independent aldosterone production in patients with CACNA1H mutations involves several factors: i) a loss of normal control of the membrane potential, ii) an increased Ca2+ influx at basal conditions, and iii) alterations in sensitivity to extracellular K+ and Na+. Finally, our findings underline the importance of CACNA1H in the control of aldosterone production and support the concept of the glomerulosa cell as an electrical oscillator.
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Affiliation(s)
- Florian Gürtler
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Katrin Jordan
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Ines Tegtmeier
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Janina Herold
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Julia Stindl
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
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10
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Morin M, Forst AL, Pérez-Torre P, Jiménez-Escrig A, Barca-Tierno V, García-Galloway E, Warth R, Lopez-Sendón Moreno JL, Moreno-Pelayo MA. Novel mutations in the KCNJ10 gene associated to a distinctive ataxia, sensorineural hearing loss and spasticity clinical phenotype. Neurogenetics 2020; 21:135-143. [PMID: 32062759 DOI: 10.1007/s10048-020-00605-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 02/01/2020] [Indexed: 12/31/2022]
Abstract
KCNJ10 encodes the inward-rectifying potassium channel (Kir4.1) that is expressed in the brain, inner ear, and kidney. Loss-of-function mutations in KCNJ10 gene cause a complex syndrome consisting of epilepsy, ataxia, intellectual disability, sensorineural deafness, and tubulopathy (EAST/SeSAME syndrome). Patients with EAST/SeSAME syndrome display renal salt wasting and electrolyte imbalance that resemble the clinical features of impaired distal tubular salt transport in Gitelman's syndrome. A key distinguishing feature between these two conditions is the additional neurological (extrarenal) manifestations found in EAST/SeSAME syndrome. Recent reports have further expanded the clinical and mutational spectrum of KCNJ10-related disorders including non-syndromic early-onset cerebellar ataxia. Here, we describe a kindred of three affected siblings with early-onset ataxia, deafness, and progressive spasticity without other prominent clinical features. By using targeted next-generation sequencing, we have identified two novel missense variants, c.488G>A (p.G163D) and c.512G>A (p.R171Q), in the KCNJ10 gene that, in compound heterozygosis, cause this distinctive EAST/SeSAME phenotype in our family. Electrophysiological characterization of these two variants confirmed their pathogenicity. When expressed in CHO cells, the R171Q mutation resulted in 50% reduction of currents compared to wild-type KCNJ10 and G163D showed a complete loss of function. Co-expression of G163D and R171Q had a more pronounced effect on currents and membrane potential than R171Q alone but less severe than single expression of G163D. Moreover, the effect of the mutations seemed less pronounced in the presence of Kir5.1 (encoded by KCNJ16), with whom the renal Kir4.1 channels form heteromers. This partial functional rescue by co-expression with Kir5.1 might explain the lack of renal symptoms in the patients. This report illustrates that a spectrum of disorders with distinct clinical symptoms may result from mutations in different parts of KCNJ10, a gene initially associated only with the EAST/SeSAME syndrome.
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Affiliation(s)
- Matias Morin
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain
| | - Anna-Lena Forst
- Medical Cell Biology, University of Regensburg, 93053, Regensburg, Germany
| | - Paula Pérez-Torre
- Servicio de Neurología, Hospital Universitario Ramón y Cajal, 28034, Madrid, Spain
| | | | - Verónica Barca-Tierno
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain
| | - Eva García-Galloway
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, 93053, Regensburg, Germany
| | | | - Miguel Angel Moreno-Pelayo
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain.
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11
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Penton D, Vohra T, Banki E, Wengi A, Weigert M, Forst AL, Bandulik S, Warth R, Loffing J. Collecting system-specific deletion of Kcnj10 predisposes for thiazide- and low-potassium diet-induced hypokalemia. Kidney Int 2020; 97:1208-1218. [PMID: 32299681 DOI: 10.1016/j.kint.2019.12.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 12/17/2022]
Abstract
The basolateral potassium channel KCNJ10 (Kir4.1), is expressed in the renal distal convoluted tubule and controls the activity of the thiazide-sensitive sodium chloride cotransporter. Loss-of-function mutations of KCNJ10 cause EAST/SeSAME syndrome with salt wasting and severe hypokalemia. KCNJ10 is also expressed in the principal cells of the collecting system. However, its pathophysiological role in this segment has not been studied in detail. To address this, we generated the mouse model AQP2cre:Kcnj10flox/flox with a deletion of Kcnj10 specifically in the collecting system (collecting system-Kcnj10-knockout). Collecting system-Kcnj10-knockout mice responded normally to standard and high potassium diet. However, this knockout exhibited a higher kaliuresis and lower plasma potassium than control mice when treated with thiazide diuretics. Likewise, collecting systemKcnj10-knockout displayed an inadequately high kaliuresis and renal sodium retention upon dietary potassium restriction. In this condition, these knockout mice became hypokalemic due to insufficient downregulation of the epithelial sodium channel (ENaC) and the renal outer medullary potassium channel (ROMK) in the collecting system. Consistently, the phenotype of collecting system-Kcnj10-knockout was fully abrogated by ENaC inhibition with amiloride and ameliorated by genetic inactivation of ROMK in the collecting system. Thus, KCNJ10 in the collecting system contributes to the renal control of potassium homeostasis by regulating ENaC and ROMK. Hence, impaired KCNJ10 function in the collecting system predisposes for thiazide and low potassium diet-induced hypokalemia and likely contributes to the pathophysiology of renal potassium loss in EAST/SeSAME syndrome.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Twinkle Vohra
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Eszter Banki
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Agnieszka Wengi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Maria Weigert
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Anna-Lena Forst
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland.
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12
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Reichold M, Klootwijk ED, Reinders J, Otto EA, Milani M, Broeker C, Laing C, Wiesner J, Devi S, Zhou W, Schmitt R, Tegtmeier I, Sterner C, Doellerer H, Renner K, Oefner PJ, Dettmer K, Simbuerger JM, Witzgall R, Stanescu HC, Dumitriu S, Iancu D, Patel V, Mozere M, Tekman M, Jaureguiberry G, Issler N, Kesselheim A, Walsh SB, Gale DP, Howie AJ, Martins JR, Hall AM, Kasgharian M, O'Brien K, Ferreira CR, Atwal PS, Jain M, Hammers A, Charles-Edwards G, Choe CU, Isbrandt D, Cebrian-Serrano A, Davies B, Sandford RN, Pugh C, Konecki DS, Povey S, Bockenhauer D, Lichter-Konecki U, Gahl WA, Unwin RJ, Warth R, Kleta R. Glycine Amidinotransferase (GATM), Renal Fanconi Syndrome, and Kidney Failure. J Am Soc Nephrol 2018; 29:1849-1858. [PMID: 29654216 DOI: 10.1681/asn.2017111179] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/27/2018] [Indexed: 12/13/2022] Open
Abstract
Background For many patients with kidney failure, the cause and underlying defect remain unknown. Here, we describe a novel mechanism of a genetic order characterized by renal Fanconi syndrome and kidney failure.Methods We clinically and genetically characterized members of five families with autosomal dominant renal Fanconi syndrome and kidney failure. We performed genome-wide linkage analysis, sequencing, and expression studies in kidney biopsy specimens and renal cells along with knockout mouse studies and evaluations of mitochondrial morphology and function. Structural studies examined the effects of recognized mutations.Results The renal disease in these patients resulted from monoallelic mutations in the gene encoding glycine amidinotransferase (GATM), a renal proximal tubular enzyme in the creatine biosynthetic pathway that is otherwise associated with a recessive disorder of creatine deficiency. In silico analysis showed that the particular GATM mutations, identified in 28 members of the five families, create an additional interaction interface within the GATM protein and likely cause the linear aggregation of GATM observed in patient biopsy specimens and cultured proximal tubule cells. GATM aggregates-containing mitochondria were elongated and associated with increased ROS production, activation of the NLRP3 inflammasome, enhanced expression of the profibrotic cytokine IL-18, and increased cell death.Conclusions In this novel genetic disorder, fully penetrant heterozygous missense mutations in GATM trigger intramitochondrial fibrillary deposition of GATM and lead to elongated and abnormal mitochondria. We speculate that this renal proximal tubular mitochondrial pathology initiates a response from the inflammasome, with subsequent development of kidney fibrosis.
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Affiliation(s)
| | | | | | | | - Mario Milani
- Italian National Research Council (CNR), Institute of Biophysics, Milan, Italy
| | | | | | | | - Sulochana Devi
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan
| | - Weibin Zhou
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan
| | | | | | | | | | | | | | | | | | - Ralph Witzgall
- Molecular and Cellular Anatomy, University Regensburg, Regensburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | - Joana R Martins
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | | | - Kevin O'Brien
- NHGRI, National Institutes of Health, Bethesda, Maryland
| | | | | | - Mahim Jain
- Department of Bone and OI, Kennedy Krieger Institute, Baltimore, Maryland
| | - Alexander Hammers
- King's College London and Guy's and St. Thomas' PET Centre, London, United Kingdom
| | | | - Chi-Un Choe
- Department of Neurology, University Hamburg, Hamburg, Germany
| | - Dirk Isbrandt
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Research Group Experimental Neurophysiology, Bonn, Germany, and University of Cologne, Cologne, Germany
| | | | | | - Richard N Sandford
- Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Christopher Pugh
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Sue Povey
- Genetics, Evolution and Environment, University College London, London, United Kingdom
| | | | - Uta Lichter-Konecki
- Division of Medical Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - William A Gahl
- NHGRI, National Institutes of Health, Bethesda, Maryland
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13
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Buehler PK, Bleiler D, Tegtmeier I, Heitzmann D, Both C, Georgieff M, Lesage F, Warth R, Thomas J. Abnormal respiration under hyperoxia in TASK-1/3 potassium channel double knockout mice. Respir Physiol Neurobiol 2017; 244:17-25. [PMID: 28673876 DOI: 10.1016/j.resp.2017.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/23/2017] [Accepted: 06/24/2017] [Indexed: 01/29/2023]
Abstract
Despite intensive research, the exact function of TASK potassium channels in central and peripheral chemoreception is still under debate. In this study, we investigated the respiration of unrestrained TASK-3 (TASK-3-/-) and TASK-1/TASK-3 double knockout (TASK-1/3-/-) adult male mice in vivo using a plethysmographic device. Ventilation parameters of TASK-3-/- mice were normal under control condition (21% O2) and upon hypoxia and hypercapnia they displayed the physiological increase of ventilation. TASK-1/3-/- mice showed increased ventilation under control conditions. This increase of ventilation was caused by increased tidal volumes (VT), a phenomenon similarly observed in TASK-1-/- mice. Under acute hypoxia, TASK-1/3-/- mice displayed the physiological increase of the minute volume. Interestingly, this increase was not related to an increase of the respiratory frequency (fR), as observed in wild-type mice, but was caused by a strong increase of VT. This particular respiratory phenotype is reminiscent of the respiratory phenotype of carotid body-denervated rodents in the compensated state. Acute hypercapnia (5% CO2) stimulated ventilation in TASK-1/3-/- and wild-type mice to a similar extent; however, at higher CO2 concentrations (>5% CO2) the stimulation of ventilation was more pronounced in TASK-1/3-/- mice. At hyperoxia (100% O2), TASK-1-/-, TASK-3-/- and wild-type mice showed the physiological small decrease of ventilation. In sharp contrast, TASK-1/3-/- mice exhibited an abnormal increase of ventilation under hyperoxia. In summary, these measurements showed a grossly normal respiration of TASK-3-/- mice and a respiratory phenotype of TASK-1/3-/- mice that was characterized by a markedly enhanced tidal volume, similar to the one observed in TASK-1-/- mice. The abnormal hyperoxia response, exclusively found in TASK-1/3-/- double mutant mice, indicates that both TASK-1 and TASK-3 are essential for the hyperoxia-induced hypoventilation. The peculiar respiratory phenotype of TASK-1/3 knockout mice is reminiscent of the respiration of animals with long-term carotid body dysfunction. Taken together, TASK-1 and TASK-3 appear to serve specific and distinct roles in the complex processes underlying chemoreception and respiratory control.
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Affiliation(s)
- Philipp K Buehler
- University Children's Hospital, Steinwiesstr. 75, CH-8032 Zürich, Switzerland
| | - Doris Bleiler
- Institute of Physiology, University of Regensburg, D-93053 Regensburg, Germany; Department of Anaesthesia, University Hospital Regensburg, 93042 Regensburg, Germany
| | - Ines Tegtmeier
- Institute of Physiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Dirk Heitzmann
- Institute of Physiology, University of Regensburg, D-93053 Regensburg, Germany; University Medical Centre Mannheim, V. Medical Clinic, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Christian Both
- University Children's Hospital, Steinwiesstr. 75, CH-8032 Zürich, Switzerland
| | - Michael Georgieff
- Institute of Anesthesiology, University of Ulm, D-89081 Ulm, Germany
| | - Florian Lesage
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, 660 Route des Lucioles, 06560, Valbonne, France
| | - Richard Warth
- Institute of Physiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Jörg Thomas
- University Children's Hospital, Steinwiesstr. 75, CH-8032 Zürich, Switzerland.
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14
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Tauber P, Aichinger B, Christ C, Stindl J, Rhayem Y, Beuschlein F, Warth R, Bandulik S. Cellular Pathophysiology of an Adrenal Adenoma-Associated Mutant of the Plasma Membrane Ca(2+)-ATPase ATP2B3. Endocrinology 2016; 157:2489-99. [PMID: 27035656 DOI: 10.1210/en.2015-2029] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adrenal aldosterone-producing adenomas (APAs) are a main cause for primary aldosteronism leading to arterial hypertension. Physiologically, aldosterone production in the adrenal gland is stimulated by angiotensin II and high extracellular potassium. These stimuli lead to a depolarization of the plasma membrane and, as a consequence, an increase of intracellular Ca(2+). Mutations of the plasma membrane Ca(2+)-ATPase ATP2B3 have been found in APAs with a prevalence of 0.6%-3.1%. Here, we investigated the effects of the APA-associated ATP2B3(Leu425_Val426del) mutation in adrenocortical NCI-H295R and human embryonic kidney (HEK-293) cells. Ca(2+) measurements revealed a higher basal Ca(2+) level in cells expressing the mutant ATP2B3. This rise in intracellular Ca(2+) was even more pronounced under conditions with high extracellular Ca(2+) pointing to an increased Ca(2+) influx associated with the mutated protein. Furthermore, cells with the mutant ATP2B3 appeared to have a reduced capacity to export Ca(2+) suggesting a loss of the physiological pump function. Surprisingly, expression of the mutant ATP2B3 caused a Na(+)-dependent inward current that strongly depolarized the plasma membrane and compromised the cytosolic cation composition. In parallel to these findings, mRNA expression of the cytochrome P450, family 11, subfamily B, polypeptide 2 (aldosterone synthase) was substantially increased and aldosterone production was enhanced in cells overexpressing mutant ATP2B3. In summary, the APA-associated ATP2B3(Leu425_Val426del) mutant promotes aldosterone production by at least 2 different mechanisms: 1) a reduced Ca(2+) export due to the loss of the physiological pump function; and 2) an increased Ca(2+) influx due to opening of depolarization-activated Ca(2+) channels as well as a possible Ca(2+) leak through the mutated pump.
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Affiliation(s)
- Philipp Tauber
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - B Aichinger
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - C Christ
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - J Stindl
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - Y Rhayem
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - F Beuschlein
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - R Warth
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - S Bandulik
- Medical Cell Biology (P.T., B.A., C.C., J.S., R.W., S.B.), University of Regensburg, 93053 Regensburg, Germany; and Medizinische Klinik und Poliklinik IV (Y.R., F.B.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
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15
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Lalli E, Barhanin J, Zennaro MC, Warth R. Local Control of Aldosterone Production and Primary Aldosteronism. Trends Endocrinol Metab 2016; 27:123-131. [PMID: 26803728 DOI: 10.1016/j.tem.2016.01.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/08/2016] [Accepted: 01/08/2016] [Indexed: 12/13/2022]
Abstract
Primary aldosteronism (PA) is caused by excessive production of aldosterone by the adrenal cortex and is determined by a benign aldosterone-producing adenoma (APA) in a significant proportion of cases. Local mechanisms, as opposed to circulatory ones, that control aldosterone production in the adrenal cortex are particularly relevant in the physiopathological setting and in the pathogenesis of PA. A breakthrough in our understanding of the pathogenetic mechanisms in APA has been the identification of somatic mutations in genes controlling membrane potential and intracellular calcium concentrations. However, recent data show that the processes of nodule formation and aldosterone hypersecretion can be dissociated in pathological adrenals and suggest a model envisaging different molecular events for the pathogenesis of APA.
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Affiliation(s)
- Enzo Lalli
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS, 06560 Valbonne, France; NEOGENEX CNRS International Associated Laboratory, 06560 Valbonne, France; Université de Nice - Sophia Antipolis, 06560 Sophia Antipolis, France.
| | - Jacques Barhanin
- Laboratoire de PhysioMédecine Moléculaire CNRS-UNS UMR 7370, 06108 Nice Cedex 2, France; Laboratories of Excellence, Ion Channel Science and Therapeutics, 06107 Nice, France
| | - Maria-Christina Zennaro
- INSERM, UMRS 970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, 75015 Paris, France
| | - Richard Warth
- Medical Cell Biology - University of Regensburg, 93053 Regensburg, Germany
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16
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Stindl J, Tauber P, Sterner C, Tegtmeier I, Warth R, Bandulik S. Pathogenesis of Adrenal Aldosterone-Producing Adenomas Carrying Mutations of the Na(+)/K(+)-ATPase. Endocrinology 2015; 156:4582-91. [PMID: 26418325 DOI: 10.1210/en.2015-1466] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aldosterone-producing adenoma (APA) is a major cause of primary aldosteronism, leading to secondary hypertension. Somatic mutations in the gene for the α1 subunit of the Na(+)/K(+)-ATPase were found in about 6% of APAs. APA-related α1 subunit of the Na(+)/K(+)-ATPase mutations lead to a loss of the pump function of the Na(+)/K(+)-ATPase, which is believed to result in membrane depolarization and Ca(2+)-dependent stimulation of aldosterone synthesis in adrenal cells. In addition, H(+) and Na(+) leak currents via the mutant Na(+)/K(+)-ATPase were suggested to contribute to the phenotype. The aim of this study was to investigate the cellular pathophysiology of adenoma-associated Na(+)/K(+)-ATPase mutants (L104R, V332G, G99R) in adrenocortical NCI-H295R cells. The expression of these Na(+)/K(+)-ATPase mutants depolarized adrenal cells and stimulated aldosterone secretion. However, an increase of basal cytosolic Ca(2+) levels in Na(+)/K(+)-ATPase mutant cells was not detectable, and stimulation with high extracellular K(+) hardly increased Ca(2+) levels in cells expressing L104R and V332G mutant Na(+)/K(+)-ATPase. Cytosolic pH measurements revealed an acidification of L104R and V332G mutant cells, despite an increased activity of the Na(+)/H(+) exchanger. The possible contribution of cellular acidification to the hypersecretion of aldosterone was supported by the observation that aldosterone secretion of normal adrenocortical cells was stimulated by acetate-induced acidification. Taken together, mutations of the Na(+)/K(+)-ATPase depolarize adrenocortical cells, disturb the K(+) sensitivity, and lower intracellular pH but, surprisingly, do not induce an overt increase of intracellular Ca(2+). Probably, the autonomous aldosterone secretion is caused by the concerted action of several pathological signaling pathways and incomplete cellular compensation.
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Affiliation(s)
- J Stindl
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - P Tauber
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - C Sterner
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - I Tegtmeier
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - R Warth
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - S Bandulik
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
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17
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Heitzmann D, Buehler P, Schweda F, Georgieff M, Warth R, Thomas J. The in vivo respiratory phenotype of the adenosine A1 receptor knockout mouse. Respir Physiol Neurobiol 2015; 222:16-28. [PMID: 26593641 DOI: 10.1016/j.resp.2015.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 11/09/2015] [Accepted: 11/09/2015] [Indexed: 10/22/2022]
Abstract
The nucleoside adenosine has been implicated in the regulation of respiration, especially during hypoxia in the newborn. In this study the role of adenosine A1 receptors for the control of respiration was investigated in vivo. To this end, respiration of unrestrained adult and neonatal adenosine A1 receptor knockout mice (A1R(-/-)) was measured in a plethysmographic device. Under control conditions (21% O2) and mild hypoxia (12-15% O2) no difference of respiratory parameters was observed between adult wildtype (A1R(+/+)) and A1R(-/-) mice. Under more severe hypoxia (6-10% O2) A1R(+/+) mice showed, after a transient increase of respiration, a decrease of respiration frequency (fR) and tidal volume (VT) leading to a decrease of minute volume (MV). This depression of respiration during severe hypoxia was absent in A1R(-/-) mice which displayed a stimulated respiration as indicated by the enhancement of MV by some 50-60%. During hypercapnia-hyperoxia (3-10% CO2/97-90 % O2), no obvious differences in respiration of A1R(-/-) and A1R(+/+) was observed. In neonatal mice, the respiratory response to hypoxia was surprisingly similar in both genotypes. However, neonatal A1R(-/-) mice appeared to have more frequently periods of apnea during hypoxia and in the post-hypoxic control period. In conclusion, these data indicate that the adenosine A1 receptor is an important molecular component mediating hypoxic depression in adult mice and it appears to stabilize respiration of neonatal mice.
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Affiliation(s)
- Dirk Heitzmann
- Medizinische Klinik, University hospital Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany
| | - Philipp Buehler
- University children's hospital, Steinwiesstr. 75, CH-8032 Zürich, Switzerland
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Michael Georgieff
- Department of Anaesthesiology, University of Ulm, D-89075 Ulm, Germany
| | - Richard Warth
- Institute of Physiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Joerg Thomas
- University children's hospital, Steinwiesstr. 75, CH-8032 Zürich, Switzerland.
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18
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Bandulik S, Tauber P, Lalli E, Barhanin J, Warth R. Two-pore domain potassium channels in the adrenal cortex. Pflugers Arch 2015; 467:1027-42. [PMID: 25339223 PMCID: PMC4428839 DOI: 10.1007/s00424-014-1628-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 12/31/2022]
Abstract
The physiological control of steroid hormone secretion from the adrenal cortex depends on the function of potassium channels. The "two-pore domain K(+) channels" (K2P) TWIK-related acid sensitive K(+) channel 1 (TASK1), TASK3, and TWIK-related K(+) channel 1 (TREK1) are strongly expressed in adrenocortical cells. They confer a background K(+) conductance to these cells which is important for the K(+) sensitivity as well as for angiotensin II and adrenocorticotropic hormone-dependent stimulation of aldosterone and cortisol synthesis. Mice with single deletions of the Task1 or Task3 gene as well as Task1/Task3 double knockout mice display partially autonomous aldosterone synthesis. It appears that TASK1 and TASK3 serve different functions: TASK1 affects cell differentiation and prevents expression of aldosterone synthase in the zona fasciculata, while TASK3 controls aldosterone secretion in glomerulosa cells. TREK1 is involved in the regulation of cortisol secretion in fasciculata cells. These data suggest that a disturbed function of K2P channels could contribute to adrenocortical pathologies in humans.
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Affiliation(s)
- Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany,
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19
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Stindl J, Tauber P, Sterner C, Tegtmeier I, Warth R, Bandulik S. Pathophysiology of Na+/K+-atpases in aldosterone secretion. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Tauber P, Christ C, Tegtmeier I, Fischer A, Rhayem Y, Warth R, Bandulik S. Cellular pathology of the mutated plasma membrane Ca2+ atpase ATP2B3 found in adrenal adenomas. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Lichtenauer U, Schmid PL, Oßwald A, Renner-Müller I, Reincke M, Warth R, Wolf E, Beuschlein F. Establishment of an in vivo model for KCNJ5 dependent hyperaldosteronism. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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Klootwijk ED, Reichold M, Unwin RJ, Kleta R, Warth R, Bockenhauer D. Renal Fanconi syndrome: taking a proximal look at the nephron. Nephrol Dial Transplant 2014; 30:1456-60. [PMID: 25492894 DOI: 10.1093/ndt/gfu377] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/15/2014] [Indexed: 11/13/2022] Open
Abstract
Renal Fanconi syndrome (RFS) refers to the generalized dysfunction of the proximal tubule (PT) (Kleta R. Fanconi or not Fanconi? Lowe syndrome revisited. Clin J Am Soc Nephrol 2008; 3: 1244-1245). In its isolated form, RFS only affects the PT, but not the other nephron segments. The study of isolated RFS can thus provide specific insights into the function of the PT. In a recent paper, Klootwijk et al. investigated one such form of isolated RFS and revealed the underlying molecular basis (Klootwijk ED, Reichold M, Helip-Wooley A et al. Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome. N Engl J Med 2014; 370: 129-138). The affected family had been described previously, demonstrating the typical features of RFS, such as low-molecular weight proteinuria, aminoaciduria, glycosuria and phosphaturia with consequent rickets; yet, importantly, patients had no evidence of impaired glomerular filtration (Tolaymat A, Sakarcan A, Neiberger R. Idiopathic Fanconi syndrome in a family. Part I. Clinical aspects. J Am Soc Nephrol 1992; 2: 1310-1317). Inheritance was consistent with an autosomal dominant mode. Klootwijk et al. discovered a surprising explanation: a heterozygous missense mutation causing partial mistargeting of the peroxisomal enzyme EHHADH to the mitochondria. Notably, disease causing was not the absence of the enzyme in the peroxisome, but its interference with mitochondrial function. The discovery of this novel disease mechanism not only confirmed the importance of mitochondrial function for PT transport, but also demonstrated the critical dependence of PT on fatty acid metabolism for energy generation.
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Affiliation(s)
| | - Markus Reichold
- Medical Cell Biology, Institute of Physiology, Regensburg, Germany
| | - Robert J Unwin
- Division of Medicine, University College London, London, UK
| | - Robert Kleta
- Centre for Nephrology, University College London, London, UK
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, Regensburg, Germany
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23
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Kuppusamy M, Caroccia B, Stindl J, Bandulik S, Lenzini L, Gioco F, Fishman V, Zanotti G, Gomez-Sanchez C, Bader M, Warth R, Rossi GP. A novel KCNJ5-insT149 somatic mutation close to, but outside, the selectivity filter causes resistant hypertension by loss of selectivity for potassium. J Clin Endocrinol Metab 2014; 99:E1765-73. [PMID: 25057880 PMCID: PMC4154085 DOI: 10.1210/jc.2014-1927] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Understanding the function of the KCNJ5 potassium channel through characterization of naturally occurring novel mutations is key for dissecting the mechanism(s) of autonomous aldosterone secretion in primary aldosteronism. OBJECTIVE We sought for such novel KCNJ5 channel mutations in a large database of patients with aldosterone-producing adenomas (APAs). METHODS We discovered a novel somatic c.446insAAC insertion, resulting in the mutant protein KCNJ5-insT149, in a patient with severe drug-resistant hypertension among 195 consecutive patients with a conclusive diagnosis of APA, 24.6% of whom showed somatic KCNJ5 mutations. By site-directed mutagenesis, we created the mutated cDNA that was transfected, along with KCNJ3 cDNA, in mammalian cells. We also localized CYP11B2 in the excised adrenal gland with immunohistochemistry and immunofluorescence using an antibody specific to human CYP11B2. Whole-cell patch clamp recordings, CYP11B2 mRNA, aldosterone measurement, and molecular modeling were performed to characterize the novel KCNJ5-insT149 mutation. RESULTS Compared with wild-type and mock-transfected adrenocortical cells, HAC15 cells expressing the mutant KCNJ5 showed increased CYP11B2 expression and aldosterone secretion. Mammalian cells expressing the mutated KCNJ5-insT149 channel exhibited a strong Na(+) inward current and, in parallel, a substantial rise in intracellular Ca(2+), caused by activation of voltage-gated Ca(2+) channels and reduced Ca(2+) elimination by Na(+)/Ca(2+) exchangers, as well as an increased production of aldosterone. CONCLUSIONS This novel mutation shows pathological Na(+) permeability, membrane depolarization, raised cytosolic Ca(2+), and increased aldosterone synthesis. Hence, a novel KCNJ5 channelopathy located after the pore α-helix preceding the selectivity filter causes constitutive secretion of aldosterone with ensuing resistant hypertension in a patient with a small APA.
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Affiliation(s)
- Maniselvan Kuppusamy
- Department of Medicine-DIMED (M.K., B.C., L.L., F.G., G.P.R.), Department of Internal Medicine 4, and Department of Biomedical Sciences (G.Z.), University of Padua, 35126 Padua, Italy; Department of Medical Cell Biology (J.S., S.B., R.W.), University of Regensburg, 93053 Regensburg, Germany; Max Delbrück Center for Molecular Medicine (V.F., M.B.), 13092 Berlin, Germany; Division of Endocrinology (C.G.-S.), G. V. (Sonny) Montgomery Veterans Affairs Medical Center and Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi 39216
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24
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Rossi GP, Kuppusamy M, Caroccia B, Bader M, Lenzini L, Stindl J, Bandulik S, Gioco F, Fishman V, Zanotti G, Gomez-Sanchez C, Warth R. Abstract 011: Identification and Electrophysiological Characterization of a Novel Somatic Mutation (insT149KCNJ5) of the Potassium Channel Kir3.4 (KCNJ5). Hypertension 2014. [DOI: 10.1161/hyp.64.suppl_1.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Context:
Understanding the function of the Kir3.4 (KCNJ5 gene) potassium channel through characterization of occurring novel mutations is key for dissecting the mechanism(s) of autonomous aldosterone secretion in primary aldosteronism.
Objective:
To identify novel KCNJ5 channel mutations and functionally characterize them in a large database of patients with aldosterone-producing adenomas (APA).
Methods:
We sequenced the APA and germinal DNA of 195 consecutive patients, diagnosed with the four corners criteria of the PAPY study. Among the 24.6% (48/195) APA patients who showed somatic KCNJ5 mutations we discovered a novel c.446insAAC insertion resulting in the mutant protein KCNJ5-insT149 in a patient with severe drug-resistant hypertension. The mutated cDNA generated by site-directed mutagenesis was transfected along with KCNJ3 cDNA in mammalian cells. 17α-hydroxylase, CYP11B1, and CYP11B2 were immunochemically localized in the excised adrenal gland. Whole-cell patch clamp recordings, CYP11B2 mRNA, aldosterone and intracellular Ca2+ measurement (Fura-2), and molecular modeling were performed to characterize the KCNJ5-insT149 mutation.
Results:
The patient’s high blood pressure was long-term cured; his LVMI fell from 168 to 106 g/m2 after 2 years follow-up. Compared to wild type and mock-transfected HAC15 adrenocortical cells, those expressing the mutant KCNJ5 showed increased CYP11B2 expression (expression fold change: 2.9±0.3, p<0.05 vs mock transfected cells) and aldosterone secretion (260 pg/μg RNA, p<0.05 vs mock cells). The HEK293 cells expressing the mutated KCNJ5-insT149 channel exhibited a strong Na+ inward current, and a substantial rise in intracellular Ca2+. The L-type Ca2+ channel blocker verapamil [10 μM] inhibited by 50% the pathological Na+ inward current, while both the Na+/Ca2+ exchanger blocker KB-R7943 [10 μM] and the removal of extracellular Na+ abolished it.
Conclusions:
We identified a novel mutation of the Kir3.4 channelopathy located after the pore α-helix preceding the selectivity filter, which causes pathological Na+ permeability, membrane depolarization, raised cytosolic Ca2+, and constitutive hypersecretion of aldosterone resulting in ensuing pseudo resistant hypertension.
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Affiliation(s)
| | | | | | - Michael Bader
- Max-Delbrück-Cntr for Molecular Medicine, Berlin, Germany
| | | | - Julia Stindl
- Med Cell Biology, Univ of Regensburg, Regensburg, Germany
| | | | | | | | | | | | - Richard Warth
- Med Cell Biology, Univ of Regensburg, Regensburg, Germany
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Tauber P, Penton D, Stindl J, Humberg E, Tegtmeier I, Sterner C, Beuschlein F, Reincke M, Barhanin J, Bandulik S, Warth R. Pharmacology and pathophysiology of mutated KCNJ5 found in adrenal aldosterone-producing adenomas. Endocrinology 2014; 155:1353-62. [PMID: 24506072 DOI: 10.1210/en.2013-1944] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Somatic mutations of the potassium channel KCNJ5 are found in 40% of aldosterone producing adenomas (APAs). APA-related mutations of KCNJ5 lead to a pathological Na(+) permeability and a rise in cytosolic Ca(2+), the latter presumably by depolarizing the membrane and activating voltage-gated Ca(2+) channels. The aim of this study was to further investigate the effects of mutated KCNJ5 channels on intracellular Na(+) and Ca(2+) homeostasis in human adrenocortical NCI-H295R cells. Expression of mutant KCNJ5 led to a 2-fold increase in intracellular Na(+) and, in parallel, to a substantial rise in intracellular Ca(2+). The increase in Ca(2+) appeared to be caused by activation of voltage-gated Ca(2+) channels and by an impairment of Ca(2+) extrusion by Na(+)/Ca(2+) exchangers. The mutated KCNJ5 exhibited a pharmacological profile that differed from the one of wild-type channels. Mutated KCNJ5 was less Ba(2+) and tertiapin-Q sensitive but was inhibited by blockers of Na(+) and Ca(2+)-transporting proteins, such as verapamil and amiloride. The clinical use of these drugs might influence aldosterone levels in APA patients with KCNJ5 mutations. This might implicate diagnostic testing of APAs and could offer new therapeutic strategies.
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Affiliation(s)
- P Tauber
- Medical Cell Biology (P.T., J.S., E.H., I.T., C.S., S.B., R.W.), University of Regensburg, 93053 Regensburg, Germany; Laboratoire de PhysioMédecine Moléculaire (D.P., J.B.), Centre National de la Recherche Scientifique, and Université de Nice Sophia Antipolis, FRE3472-Laboratoire de PhysioMédecine Moléculaire, 06108 Nice Cedex, France; Laboratories of Excellence, Ion Channel Science and Therapeutics (D.P., J.B.), France; and Medizinische Klinik und Poliklinik IV (F.B., M.R.), Ludwig-Maximilians-Universität, 80336 Munich, Germany
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Spyroglou A, Bozoglu T, Rawal R, De Leonardis F, Sterner C, Boulkroun S, Benecke AG, Monti L, Zennaro MC, Petersen AK, Döring A, Rossi A, Bidlingmaier M, Warth R, Gieger C, Reincke M, Beuschlein F. Diastrophic dysplasia sulfate transporter (SLC26A2) is expressed in the adrenal cortex and regulates aldosterone secretion. Hypertension 2014; 63:1102-9. [PMID: 24591336 DOI: 10.1161/hypertensionaha.113.02504] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Elucidation of the molecular mechanisms leading to autonomous aldosterone secretion is a prerequisite to define potential targets and biomarkers in the context of primary aldosteronism. After a genome-wide association study with subjects from the population-based Cooperative Health Research in the Region of Augsburg F4 survey, we observed a highly significant association (P=6.78×10(-11)) between the aldosterone to renin ratio and a locus at 5q32. Hypothesizing that this locus may contain genes of relevance for the pathogenesis of primary aldosteronism, we investigated solute carrier family 26 member 2 (SLC26A2), a protein with known transport activity for sulfate and other cations. Within murine tissues, adrenal glands showed the highest expression levels for SLC26A2, which was significantly downregulated on in vivo stimulation with angiotensin II and potassium. SLC26A2 expression was found to be significantly lower in aldosterone-producing adenomas in comparison with normal adrenal glands. In adrenocortical NCI-H295R cells, specific knockdown of SLC26A2 resulted in a highly significant increase in aldosterone secretion. Concomitantly, expression of steroidogenic enzymes, as well as upstream effectors including transcription factors such as NR4A1, CAMK1, and intracellular Ca(2+) content, was upregulated in knockdown cells. To substantiate further these findings in an SLC26A2 mutant mouse model, aldosterone output proved to be increased in a sex-specific manner. In summary, these findings point toward a possible effect of SLC26A2 in the regulation of aldosterone secretion potentially involved in the pathogenesis of primary aldosteronism.
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Affiliation(s)
- Ariadni Spyroglou
- Endocrine Research Unit, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Ziemssenstr. 1, D-80336 Munich, Germany.
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27
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Ganschow P, Warth R, Hinz U, Büchler MW, Kadmon M. Early postoperative complications after stapled vs handsewn restorative proctocolectomy with ileal pouch-anal anastomosis in 148 patients with familial adenomatous polyposis coli: a matched-pair analysis. Colorectal Dis 2014; 16:116-22. [PMID: 23941307 DOI: 10.1111/codi.12385] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 04/09/2013] [Indexed: 12/13/2022]
Abstract
AIM Restorative proctocolectomy with ileal pouch-anal anastomosis for patients with familial adenomatous polyposis (FAP) and ulcerative colitis (UC) has been modified from a transanal hand-suture after mucosectomy to a stapled ileal pouch-anal anastomosis (IPAA) without mucosectomy. Better functional results favour stapled anastomosis; however, stapled anastomosis results in higher rates of adenomas in persisting anorectal mucosa. The purpose of this study was to compare the two techniques of pouch-anal anastomosis with respect to early postoperative complications in a collective of FAP patients. METHOD The study was performed as a matched-pair analysis. Data were obtained from a prospectively collected database. RESULTS The overall rate of postoperative complications was higher after stapled IPAA (31% stapled vs 23% handsewn), with anastomotic stricture occurring in 24.3% (stapled) and 16.2% (handsewn) (P = 0.22). Any leakage or pelvic abscess formation after stapled anastomosis occurred within 30 days in almost all patients, whereas these were mainly diagnosed between 30 days and 6 months after handsewn IPAA. A laparoscopic approach was used in 56.7% of patients in the stapled group but in only two patients in the handsewn group. Intra-operative blood loss was significantly higher in the handsewn group (mean ± SD: 699 ± 511 ml vs 369 ± 343 ml; P < 0.0001), as was the volume of blood transfused (mean ± SD: 205 ± 365 ml vs 8 ± 49 ml; P < 0.0001). Function did not differ between the groups. CONCLUSION There was a nonstatistically significant tendency towards a higher rate of early postoperative complications after stapled IPAA. The timing of anastomotic leakage and abscess formation differed between the groups.
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Affiliation(s)
- P Ganschow
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
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28
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Klootwijk ED, Reichold M, Helip-Wooley A, Tolaymat A, Broeker C, Robinette SL, Reinders J, Peindl D, Renner K, Eberhart K, Assmann N, Oefner PJ, Dettmer K, Sterner C, Schroeder J, Zorger N, Witzgall R, Reinhold SW, Stanescu HC, Bockenhauer D, Jaureguiberry G, Courtneidge H, Hall AM, Wijeyesekera AD, Holmes E, Nicholson JK, O'Brien K, Bernardini I, Krasnewich DM, Arcos-Burgos M, Izumi Y, Nonoguchi H, Jia Y, Reddy JK, Ilyas M, Unwin RJ, Gahl WA, Warth R, Kleta R. Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome. N Engl J Med 2014; 370:129-38. [PMID: 24401050 DOI: 10.1056/nejmoa1307581] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND In renal Fanconi's syndrome, dysfunction in proximal tubular cells leads to renal losses of water, electrolytes, and low-molecular-weight nutrients. For most types of isolated Fanconi's syndrome, the genetic cause and underlying defect remain unknown. METHODS We clinically and genetically characterized members of a five-generation black family with isolated autosomal dominant Fanconi's syndrome. We performed genomewide linkage analysis, gene sequencing, biochemical and cell-biologic investigations of renal proximal tubular cells, studies in knockout mice, and functional evaluations of mitochondria. Urine was studied with the use of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy. RESULTS We linked the phenotype of this family's Fanconi's syndrome to a single locus on chromosome 3q27, where a heterozygous missense mutation in EHHADH segregated with the disease. The p.E3K mutation created a new mitochondrial targeting motif in the N-terminal portion of EHHADH, an enzyme that is involved in peroxisomal oxidation of fatty acids and is expressed in the proximal tubule. Immunocytofluorescence studies showed mistargeting of the mutant EHHADH to mitochondria. Studies of proximal tubular cells revealed impaired mitochondrial oxidative phosphorylation and defects in the transport of fluids and a glucose analogue across the epithelium. (1)H-NMR spectroscopy showed elevated levels of mitochondrial metabolites in urine from affected family members. Ehhadh knockout mice showed no abnormalities in renal tubular cells, a finding that indicates a dominant negative nature of the mutation rather than haploinsufficiency. CONCLUSIONS Mistargeting of peroxisomal EHHADH disrupts mitochondrial metabolism and leads to renal Fanconi's syndrome; this indicates a central role of mitochondria in proximal tubular function. The dominant negative effect of the mistargeted protein adds to the spectrum of monogenic mechanisms of Fanconi's syndrome. (Funded by the European Commission Seventh Framework Programme and others.).
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Affiliation(s)
- Enriko D Klootwijk
- From the Centre for Nephrology (E.D.K., H.C.S., D.B., G.J., H.C., A.M.H., R.J.U., R.K.) and Institute of Child Health (D.B., R.K.), University College London, and Biomolecular Medicine, Imperial College London (S.L.R., A.D.W., E.H., J.K.N.) - both in London; the Departments of Medical Cell Biology (M.R., C.B., D.P., C.S., R. Warth), Internal Medicine III (K.R.), Internal Medicine II (S.W.R.), and Molecular and Cellular Anatomy (R. Witzgall) and the Institutes of Functional Genomics (J.R., K.E., N.A., P.J.O., K.D.) and Pathology (J.S.), University of Regensburg, and the Department of Radiology, Barmherzige Brueder Hospital (N.Z.) - all in Regensburg, Germany; the National Human Genome Research Institute (A.H.-W., S.L.R., H.C.S., K.O., I.B., D.M.K., W.A.G., R.K.) and National Heart, Lung, and Blood Institute (Y.I.), National Institutes of Health, Bethesda, MD; the Division of Pediatric Nephrology, University of Florida, Jacksonville (A.T., M.I.); the Genome Biology Department, Australian National University, Canberra, ACT, Australia (M.A.-B.); Kitasato University Medical Center, Saitama, Japan (H.N.); and the Department of Pathology, Northwestern University, Chicago (Y.J., J.K.R.)
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29
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Williams TA, Monticone S, Schack VR, Stindl J, Burrello J, Buffolo F, Annaratone L, Castellano I, Beuschlein F, Reincke M, Lucatello B, Ronconi V, Fallo F, Bernini G, Maccario M, Giacchetti G, Veglio F, Warth R, Vilsen B, Mulatero P. Somatic
ATP1A1
,
ATP2B3
, and
KCNJ5
Mutations in Aldosterone-Producing Adenomas. Hypertension 2014; 63:188-95. [DOI: 10.1161/hypertensionaha.113.01733] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aldosterone-producing adenomas (APAs) cause a sporadic form of primary aldosteronism and somatic mutations in the
KCNJ5
gene, which encodes the G-protein–activated inward rectifier K
+
channel 4, GIRK4, account for ≈40% of APAs. Additional somatic APA mutations were identified recently in 2 other genes,
ATP1A1
and
ATP2B3
, encoding Na
+
/K
+
-ATPase 1 and Ca
2+
-ATPase 3, respectively, at a combined prevalence of 6.8%. We have screened 112 APAs for mutations in known hotspots for genetic alterations associated with primary aldosteronism. Somatic mutations in
ATP1A1
,
ATP2B3
, and
KCNJ5
were present in 6.3%, 0.9%, and 39.3% of APAs, respectively, and included 2 novel mutations (Na
+
/K
+
-ATPase p.Gly99Arg and GIRK4 p.Trp126Arg).
CYP11B2
gene expression was higher in APAs harboring
ATP1A1
and
ATP2B3
mutations compared with those without these or
KCNJ5
mutations. Overexpression of Na
+
/K
+
-ATPase p.Gly99Arg and GIRK4 p.Trp126Arg in HAC15 adrenal cells resulted in upregulation of
CYP11B2
gene expression and its transcriptional regulator
NR4A2.
Structural modeling of the Na
+
/K
+
-ATPase showed that the Gly99Arg substitution most likely interferes with the gateway to the ion binding pocket. In vitro functional assays demonstrated that Gly99Arg displays severely impaired ATPase activity, a reduced apparent affinity for Na
+
activation of phosphorylation and K
+
inhibition of phosphorylation that indicate decreased Na
+
and K
+
binding, respectively. Moreover, whole cell patch-clamp studies established that overexpression of Na
+
/K
+
-ATPase Gly99Arg causes membrane voltage depolarization. In conclusion, somatic mutations are common in APAs that result in an increase in
CYP11B2
gene expression and may account for the dysregulated aldosterone production in a subset of patients with sporadic primary aldosteronism.
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Affiliation(s)
- Tracy Ann Williams
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Silvia Monticone
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Vivien R. Schack
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Julia Stindl
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Jacopo Burrello
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Fabrizio Buffolo
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Laura Annaratone
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Isabella Castellano
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Felix Beuschlein
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Martin Reincke
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Barbara Lucatello
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Vanessa Ronconi
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Francesco Fallo
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Giampaolo Bernini
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Mauro Maccario
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Gilberta Giacchetti
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Franco Veglio
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Richard Warth
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Bente Vilsen
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
| | - Paolo Mulatero
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., J.B., F. Buffolo, F.V., P.M.), Division of Pathology (L.A., I.C.), and Division of Endocrinology, Diabetes, and Metabolism (B.L., M.M.), Department of Medical Sciences, University of Torino, Torino, Italy; Department of Biomedicine, Aarhus University, Aarhus, Denmark (V.R.S., B.V.); Medical Cell Biology, University of Regensburg, Regensburg, Germany (J.S., R.W.); Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians
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30
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Schmidt K, Ripper M, Tegtmeier I, Humberg E, Sterner C, Reichold M, Warth R, Bandulik S. Dynamics of Renal Electrolyte Excretion in Growing Mice. ACTA ACUST UNITED AC 2013; 124:7-13. [DOI: 10.1159/000356816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 10/25/2013] [Indexed: 11/19/2022]
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31
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Monticone S, Hattangady NG, Penton D, Isales CM, Edwards MA, Williams TA, Sterner C, Warth R, Mulatero P, Rainey WE. a Novel Y152C KCNJ5 mutation responsible for familial hyperaldosteronism type III. J Clin Endocrinol Metab 2013; 98:E1861-5. [PMID: 24037882 PMCID: PMC3816265 DOI: 10.1210/jc.2013-2428] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Primary aldosteronism is a heterogeneous group of disorders comprising both sporadic and familial forms. Mutations in the KCNJ5 gene, which encodes the inward rectifier K(+) channel 4 (G protein-activated inward rectifier K(+) channel 4, Kir3.4), cause familial hyperaldosteronism type III (FH-III) and are involved in the pathogenesis of sporadic aldosterone-producing adenomas. OBJECTIVE The objective of the study was to characterize the effects of a newly described KCNJ5 mutation in vitro. PATIENTS AND METHODS The index case is a 62-year-old woman affected by primary aldosteronism, who underwent left adrenalectomy after workup for adrenal adenoma. Exon 1 of KCNJ5 was PCR amplified from adrenal tissue and peripheral blood and sequenced. Electrophysiological and gene expression studies were performed to establish the functional effects of the new mutation on the membrane potential and adrenal cell CYP11B2 expression. RESULTS KCNJ5 sequencing in the index case revealed a new p.Y152C germline mutation; interestingly, the phenotype of the patient was milder than most of the previously described FH-III families. The tyrosine-to-cysteine substitution resulted in pathological Na(+) permeability, cell membrane depolarization, and disturbed intracellular Ca(2+) homeostasis, effects similar, albeit smaller, to the ones demonstrated for other KCNJ5 mutations. Gene expression studies revealed an increased expression of CYP11B2 and its transcriptional regulator NR4A2 in HAC15 adrenal cells overexpressing KCNJ5(Y152C) compared to the wild-type channel. The effect was clearly Ca(2+)-dependent, because it was abolished by the calcium channel blocker nifedipine. CONCLUSIONS Herein we describe a new germline mutation in KCNJ5 responsible for FH-III.
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Affiliation(s)
- Silvia Monticone
- Department of Medical Sciences, Medicina Interna 4, University of Torino, Via Genova 3, 10126 Torino, Italy.
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32
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Burghardt T, Kastner J, Suleiman H, Rivera-Milla E, Stepanova N, Lottaz C, Kubitza M, Böger CA, Schmidt S, Gorski M, de Vries U, Schmidt H, Hertting I, Kopp J, Rascle A, Moser M, Heid IM, Warth R, Spang R, Wegener J, Mierke CT, Englert C, Witzgall R. LMX1B is essential for the maintenance of differentiated podocytes in adult kidneys. J Am Soc Nephrol 2013; 24:1830-48. [PMID: 23990680 DOI: 10.1681/asn.2012080788] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Mutations of the LMX1B gene cause nail-patella syndrome, a rare autosomal-dominant disorder affecting the development of the limbs, eyes, brain, and kidneys. The characterization of conventional Lmx1b knockout mice has shown that LMX1B regulates the development of podocyte foot processes and slit diaphragms, but studies using podocyte-specific Lmx1b knockout mice have yielded conflicting results regarding the importance of LMX1B for maintaining podocyte structures. In order to address this question, we generated inducible podocyte-specific Lmx1b knockout mice. One week of Lmx1b inactivation in adult mice resulted in proteinuria with only minimal foot process effacement. Notably, expression levels of slit diaphragm and basement membrane proteins remained stable at this time point, and basement membrane charge properties also did not change, suggesting that alternative mechanisms mediate the development of proteinuria in these mice. Cell biological and biophysical experiments with primary podocytes isolated after 1 week of Lmx1b inactivation indicated dysregulation of actin cytoskeleton organization, and time-resolved DNA microarray analysis identified the genes encoding actin cytoskeleton-associated proteins, including Abra and Arl4c, as putative LMX1B targets. Chromatin immunoprecipitation experiments in conditionally immortalized human podocytes and gel shift assays showed that LMX1B recognizes AT-rich binding sites (FLAT elements) in the promoter regions of ABRA and ARL4C, and knockdown experiments in zebrafish support a model in which LMX1B and ABRA act in a common pathway during pronephros development. Our report establishes the importance of LMX1B in fully differentiated podocytes and argues that LMX1B is essential for the maintenance of an appropriately structured actin cytoskeleton in podocytes.
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33
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Bandulik S, Tauber P, Penton D, Schweda F, Tegtmeier I, Sterner C, Lalli E, Lesage F, Hartmann M, Barhanin J, Warth R. Severe hyperaldosteronism in neonatal Task3 potassium channel knockout mice is associated with activation of the intraadrenal renin-angiotensin system. Endocrinology 2013; 154:2712-22. [PMID: 23698720 DOI: 10.1210/en.2013-1101] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Task3 K(+) channels are highly expressed in the adrenal cortex and contribute to the angiotensin II and K(+) sensitivity of aldosterone-producing glomerulosa cells. Adult Task3(-/-) mice display a partially autonomous aldosterone secretion, subclinical hyperaldosteronism, and salt-sensitive hypertension. Here, we investigated the age dependence of the adrenal phenotype of Task3(-/-) mice. Compared with adults, newborn Task3(-/-) mice displayed a severe adrenal phenotype with strongly increased plasma levels of aldosterone, corticosterone, and progesterone. This adrenocortical dysfunction was accompanied by a modified gene expression profile. The most strongly up-regulated gene was the protease renin. Real-time PCR corroborated the strong increase in adrenal renin expression, and immunofluorescence revealed renin-expressing cells in the zona fasciculata. Together with additional factors, activation of the local adrenal renin system is probably causative for the severely disturbed steroid hormone secretion of neonatal Task3(-/-) mice. The changes in gene expression patterns of neonatal Task3(-/-) mice could also be relevant for other forms of hyperaldosteronism.
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Affiliation(s)
- Sascha Bandulik
- Department of Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany.
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Penton D, Bandulik S, Schweda F, Haubs S, Tauber P, Reichold M, Cong LD, El Wakil A, Budde T, Lesage F, Lalli E, Zennaro MC, Warth R, Barhanin J. Task3 potassium channel gene invalidation causes low renin and salt-sensitive arterial hypertension. Endocrinology 2012; 153:4740-8. [PMID: 22878402 DOI: 10.1210/en.2012-1527] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Task1 and Task3 potassium channels (Task: tandem of P domains in a weak inward rectifying K(+) channel-related acid-sensitive K(+) channel) are believed to control the membrane voltage of aldosterone-producing adrenal glomerulosa cells. This study aimed at understanding the role of Task3 for the control of aldosterone secretion. The adrenal phenotype of Task3(-/-) mice was investigated using electrophysiology, adrenal slices, and blood pressure measurements. Primary adrenocortical cells of Task3(-/-) mice were strongly depolarized compared with wild-type (-52 vs. -79 mV), and in fresh adrenal slices Ca(2+) signaling of Task3(-/-) glomerulosa cells was abnormal. In living Task3(-/-) mice, the regulation of aldosterone secretion showed specific deficits: Under low Na(+) and high K(+) diets, protocols known to increase aldosterone, and under standard diet, Task3 inactivation was compensated and aldosterone was normal. However, high Na(+) and low K(+) diets, two protocols known to lower aldosterone, failed to lower aldosterone in Task3(-/-) mice. The physiological regulation of aldosterone was disturbed: aldosterone-renin ratio, an indicator of autonomous aldosterone secretion, was 3-fold elevated at standard and high Na(+) diets. Isolated adrenal glands of Task3(-/-) produced 2-fold more aldosterone. As a consequence, Task3(-/-) mice showed salt-sensitive arterial hypertension (plus 10 mm Hg). In conclusion, Task3 plays an important role in the adaptation of aldosterone secretion to dietary salt intake.
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Affiliation(s)
- David Penton
- University of Regensburg, 93053 Regensburg, Germany
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El Wakil A, Bandulik S, Guy N, Bendahhou S, Zennaro MC, Niehrs C, Mari B, Warth R, Barhanin J, Lalli E. Dkk3 is a component of the genetic circuitry regulating aldosterone biosynthesis in the adrenal cortex. Hum Mol Genet 2012; 21:4922-9. [DOI: 10.1093/hmg/dds333] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Williams TA, Monticone S, Crudo V, Warth R, Veglio F, Mulatero P. Visinin-Like 1 Is Upregulated in Aldosterone-Producing Adenomas With
KCNJ5
Mutations and Protects From Calcium-Induced Apoptosis. Hypertension 2012; 59:833-9. [DOI: 10.1161/hypertensionaha.111.188532] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Visinin-like 1 (
VSNL1
) is upregulated in aldosterone-producing adenomas (APAs) compared with normal adrenals. We demonstrate that
VSNL1
overexpression in adrenocortical carcinoma cells (NCI H295R) upregulates basal and angiotensin II–stimulated
CYP11B2
gene expression 3.2- and 1.5-fold, respectively. Conversely, silencing
VSNL1
by RNA interference decreases angiotensin II–stimulated
CYP11B2
expression and aldosterone secretion by 41.0% and 34.5%, respectively. Mutations in the potassium channel
KCNJ5
have been identified in APAs that result in sodium influx and membrane depolarization and are postulated to result in calcium influx in adrenal glomerulosa cells.
VSNL1
and
CYP11B2
are 8.1- and 6.0-fold more highly expressed, respectively, in APAs harboring
KCNJ5
mutations compared with those without, and the upregulation of
VSNL1
in these APAs accounts for the overexpression of
VSNL1
in the total APA sample set compared with normal adrenals. Silencing
VSNL1
in H295R cells renders them sensitive to ionomycin-induced apoptosis, indicating that
VSNL1
protects these cells against calcium-induced cell death. Concomitant expression of mutated KCNJ5 (G151R) and silencing
VSNL1
results in apoptosis of H295R cells, an effect that is blocked by nifedipine and is absent using a control small-interfering RNA or when wild-type KCNJ5 is expressed and
VSNL1
is silenced. These data demonstrate that
VSNL1
plays a dual function in vitro in the regulation of
CYP11B2
gene expression and in the inhibition of calcium-induced apoptosis. In addition,
VSNL1
may play a role in the pathophysiology of APAs harboring mutations in the potassium channel
KCNJ5
via its antiapoptotic function in response to calcium cytotoxicity and its effect on aldosterone production.
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Affiliation(s)
- Tracy Ann Williams
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., V.C., F.V., P.M.), Department of Medicine and Experimental Oncology, University of Torino, Torino, Italy; Medical Cell Biology (R.W.), University of Regensburg, Regensburg, Germany
| | - Silvia Monticone
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., V.C., F.V., P.M.), Department of Medicine and Experimental Oncology, University of Torino, Torino, Italy; Medical Cell Biology (R.W.), University of Regensburg, Regensburg, Germany
| | - Valentina Crudo
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., V.C., F.V., P.M.), Department of Medicine and Experimental Oncology, University of Torino, Torino, Italy; Medical Cell Biology (R.W.), University of Regensburg, Regensburg, Germany
| | - Richard Warth
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., V.C., F.V., P.M.), Department of Medicine and Experimental Oncology, University of Torino, Torino, Italy; Medical Cell Biology (R.W.), University of Regensburg, Regensburg, Germany
| | - Franco Veglio
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., V.C., F.V., P.M.), Department of Medicine and Experimental Oncology, University of Torino, Torino, Italy; Medical Cell Biology (R.W.), University of Regensburg, Regensburg, Germany
| | - Paolo Mulatero
- From the Division of Internal Medicine and Hypertension (T.A.W., S.M., V.C., F.V., P.M.), Department of Medicine and Experimental Oncology, University of Torino, Torino, Italy; Medical Cell Biology (R.W.), University of Regensburg, Regensburg, Germany
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Mulatero P, Tauber P, Zennaro MC, Monticone S, Lang K, Beuschlein F, Fischer E, Tizzani D, Pallauf A, Viola A, Amar L, Williams TA, Strom TM, Graf E, Bandulik S, Penton D, Plouin PF, Warth R, Allolio B, Jeunemaitre X, Veglio F, Reincke M. KCNJ5
Mutations in European Families With Nonglucocorticoid Remediable Familial Hyperaldosteronism. Hypertension 2012; 59:235-40. [DOI: 10.1161/hypertensionaha.111.183996] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Paolo Mulatero
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Philipp Tauber
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Maria-Christina Zennaro
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Silvia Monticone
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Katharina Lang
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Felix Beuschlein
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Evelyn Fischer
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Davide Tizzani
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Anna Pallauf
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Andrea Viola
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Laurence Amar
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Tracy Ann Williams
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Tim M. Strom
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Elisabeth Graf
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Sascha Bandulik
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - David Penton
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Pierre-François Plouin
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Richard Warth
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Bruno Allolio
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Xavier Jeunemaitre
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Franco Veglio
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
| | - Martin Reincke
- From the Division of Internal Medicine and Hypertension (P.M., S.M., D.T., A.V., T.A.W., F.V.), University of Torino, Torino, Italy; Medical Cell Biology (P.T., S.B., D.P., R.W.), University Regensburg, Regensburg, Germany; Institut National de la Santé et de la Recherche Médicale (M.C.Z., L.A., P.F.P., X.J.), U970, Paris Cardiovascular Research Center, Paris, France; University Paris Descartes (M.C.Z., L.A., P.F.P., X.J.), Paris, France; Assistance Publique-Hôpitaux de Paris (M.C.Z., L.A., P.F.P.,
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Liu W, Schreck C, Coleman RA, Wade JB, Hernandez Y, Zavilowitz B, Warth R, Kleyman TR, Satlin LM. Role of NKCC in BK channel-mediated net K⁺ secretion in the CCD. Am J Physiol Renal Physiol 2011; 301:F1088-97. [PMID: 21816753 DOI: 10.1152/ajprenal.00347.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Apical SK/ROMK and BK channels mediate baseline and flow-induced K secretion (FIKS), respectively, in the cortical collecting duct (CCD). BK channels are detected in acid-base transporting intercalated (IC) and Na-absorbing principal (PC) cells. Although the density of BK channels is greater in IC than PC, Na-K-ATPase activity in IC is considered inadequate to sustain high rates of urinary K secretion. To test the hypothesis that basolateral NKCC in the CCD contributes to BK channel-mediated FIKS, we measured net K secretion (J(K)) and Na absorption (J(Na)) at slow (∼1) and fast (∼5 nl·min(-1)·mm(-1)) flow rates in rabbit CCDs microperfused in vitro in the absence and presence of bumetanide, an inhibitor of NKCC, added to the bath. Bumetanide inhibited FIKS but not basal J(K), J(Na), or the flow-induced [Ca(2+)](i) transient necessary for BK channel activation. Addition of luminal iberiotoxin, a BK channel inhibitor, to bumetanide-treated CCDs did not further reduce J(K). Basolateral Cl removal reversibly inhibited FIKS but not basal J(K) or J(Na). Quantitative PCR performed on single CCD samples using NKCC1- and 18S-specific primers and probes and the TaqMan assay confirmed the presence of the transcript in this nephron segment. To identify the specific cell type to which basolateral NKCC is localized, we exploited the ability of NKCC to accept NH(4)(+) at its K-binding site to monitor the rate of bumetanide-sensitive cytosolic acidification after NH(4)(+) addition to the bath in CCDs loaded with the pH indicator dye BCECF. Both IC and PC were found to have a basolateral bumetanide-sensitive NH(4)(+) entry step and NKCC1-specific antibodies labeled the basolateral surfaces of both cell types in CCDs. These results suggest that BK channel-mediated FIKS is dependent on a basolateral bumetanide-sensitive, Cl-dependent transport pathway, proposed to be NKCC1, in both IC and PC in the CCD.
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Affiliation(s)
- Wen Liu
- Division of Pediatric Nephrology, Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029, USA
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39
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Moor AE, Guevara C, Altermatt HJ, Warth R, Jaggi R, Aebi S. PRO_10--a new tissue-based prognostic multigene marker in patients with early estrogen receptor-positive breast cancer. Pathobiology 2011; 78:140-8. [PMID: 21613801 DOI: 10.1159/000323809] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 12/22/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND/AIMS Clinicopathological and molecular factors determine the prognosis of breast cancer. PRO_10 is a prognostic score based on quantitative RT-PCR of 10 proliferation-associated genes obtained from formalin-fixed, paraffin-embedded breast cancer tissues. We revalidated PRO_10 in patients treated in a non-trial setting. METHODS The charts of 315 patients with postmenopausal estrogen receptor (ER)-positive breast cancer between 1996 and 2004 were reviewed. Forty-eight cases relapsed within 5 years of diagnosis; they were paired with controls by matching the N and T stage, histological grade, percent ER-positive cells, human epidermal growth factor receptor 2, age, adjuvant chemo- and endocrine therapy. The score was tested by conditional logistic regression. RESULTS Despite strict matching, PRO_10 remained prognostic for recurrence in the whole group (odds ratio, OR = 4.7, p = 0.005) and in subgroups of grade 2 (OR = 5.5, p = 0.009) and N0 cancers (OR = 15, p = 0.002). Five-year recurrence-free survival was 29% in patients with high and 67% in patients with low scores (p = 0.002). PRO_10 was prognostic for overall survival (5-year overall survival 71 vs. 91%). CONCLUSION PRO_10 is an independent prognostic marker in postmenopausal ER-positive breast cancer. It is based on formalin-fixed, paraffin-embedded tissue and could be integrated easily into the routine diagnostic workflow.
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Affiliation(s)
- A E Moor
- Department of Clinical Research, University of Bern, Switzerland
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40
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Thompson DA, Feather S, Stanescu HC, Freudenthal B, Zdebik AA, Warth R, Ognjanovic M, Hulton SA, Wassmer E, van't Hoff W, Russell-Eggitt I, Dobbie A, Sheridan E, Kleta R, Bockenhauer D. Altered electroretinograms in patients with KCNJ10 mutations and EAST syndrome. J Physiol 2011; 589:1681-9. [PMID: 21300747 DOI: 10.1113/jphysiol.2010.198531] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The K+ channel expressed by the KCNJ10 gene (Kir4.1) has previously demonstrated importance in retinal function in animal experiments. Recently, mutations in KCNJ10 were recognised as pathogenic in man, causing a constellation of symptoms, including epilepsy, ataxia, sensorineural deafness and a renal tubulopathy designated as EAST syndrome. We have studied the impact of KCNJ10 mutations on the human electroretinogram (ERG) in four unrelated patients with EAST syndrome. Corneal ganzfeld ERGs were elicited in response to flash stimuli of strengths of 0.001–10 phot cd s/m2 presented scotopically, and 0.3–10 phot cd s/m2 presented photopically. ERG waveforms from light-adapted retinae of all patients showed reduced amplitudes of the photopic negative response (PhNR) (P < 0.001). The photopic ERGs showed a delay in b-wave time to peak, but the photopic hill, i.e. the relative variation of time to peak and amplitude with luminance flash strength, was preserved. Scotopic ERGs to flash strengths 0.01 to 0.1 phot cd s/m2 showed a delay of up to 20 ms before the onset of the b-wave in two patients compared to controls. Stimulus–response functions were fitted by Michaelis–Menten equations and showed significantly lower retinal sensitivity in two patients than in controls (P < 0.001). Our study for the first time in the human ERG shows changes in association with KCNJ10 mutations affecting a Muller cell K+ channel. These data illustrate the role of KCNJ10 function in the physiology of proximal and possibly also the distal human retina.
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Affiliation(s)
- Dorothy A Thompson
- The Tony Kriss Visual Electrophysiology Unit, Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital/University College London, London WC1 N3JH, UK.
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41
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Abstract
Background: The general transcription factor II H (TFIIH), comprised of a core complex and an associated CAK-complex, functions in transcription, DNA repair and cell cycle control. Mutations of the two largest subunits, p89 (XPB) and p80 (XPD), cause the hereditary cancer-prone syndrome xeroderma pigmentosum. Methods: The TFIIH subunit p89 was monitored during interphase and cell division by immunofluorescence staining, GFP-fusion constructs including deletions, live cell imaging and immuno-precipitations. Results: Here we demonstrate that during cell division, from prophase until telophase, the TFIIH core subunit p89, but not other subunits of TFIIH, associates with the centrosomes and the adjacent parts of the mitotic spindle. With overall constant levels throughout mitosis, p89 re-localizes to the newly formed nuclei by the end of mitosis. Furthermore, p89 interacts with the centrosomal protein γ-tubulin. Truncations of p89 result in an abnormal subcellular distribution during interphase and abolished centrosomal association during mitosis. Conclusions: Our observations suggest a so far unappreciated role for p89 in cell cycle regulation, and may be the structural basis for a long known, but hitherto unexplained interaction between p89 and tubulin.
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Affiliation(s)
- Achim Weber
- Department of Pathology, Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland.
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42
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Abstract
Potassium channels control the membrane voltage of aldosterone-producing zona glomerulosa cells. They are responsible for the unique K(+) sensitivity of these cells and are important molecular targets of angiotensin II signaling. Among the 78 pore-forming K(+) channels in human genome only a few are found in adrenal glands. The 2-P-domain K(+) channels TASK1 and TASK3 are strongly expressed in the adrenal cortex and produce a background K(+) conductance, which is pivotal for the regulation of the aldosterone secretion in zona glomerulosa cells. Disruption of the TASK1 gene in mice resulted in an autonomous aldosterone production and caused a remarkable aberrant expression of aldosterone synthase in zona fasciculata cells that normally produce glucocorticoids. After puberty, only in male mice aldosterone production was switched off in the zona fasciculata and regular zonation of aldosterone synthase occurred. In double mutant TASK1(-/-)/TASK3(-/-) mice, also adult male mice displayed primary hyperaldosteronism. Therefore, these knockout mice are interesting models to study mechanisms of autonomous aldosterone production and adrenocortical zonation. These data suggest that modifications of the adrenocortical K(+) conductances could also contribute to autonomic aldosterone production and primary hyperaldosteronism in humans.
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Affiliation(s)
- S Bandulik
- Physiology, University of Regensburg, Regensburg, Germany
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43
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Gestreau C, Heitzmann D, Thomas J, Dubreuil V, Bandulik S, Reichold M, Bendahhou S, Pierson P, Sterner C, Peyronnet-Roux J, Benfriha C, Tegtmeier I, Ehnes H, Georgieff M, Lesage F, Brunet JF, Goridis C, Warth R, Barhanin J. Task2 potassium channels set central respiratory CO2 and O2 sensitivity. Proc Natl Acad Sci U S A 2010; 107:2325-30. [PMID: 20133877 PMCID: PMC2836670 DOI: 10.1073/pnas.0910059107] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Task2 K(+) channel expression in the central nervous system is surprisingly restricted to a few brainstem nuclei, including the retrotrapezoid (RTN) region. All Task2-positive RTN neurons were lost in mice bearing a Phox2b mutation that causes the human congenital central hypoventilation syndrome. In plethysmography, Task2(-/-) mice showed disturbed chemosensory function with hypersensitivity to low CO(2) concentrations, leading to hyperventilation. Task2 probably is needed to stabilize the membrane potential of chemoreceptive cells. In addition, Task2(-/-) mice lost the long-term hypoxia-induced respiratory decrease whereas the acute carotid-body-mediated increase was maintained. The lack of anoxia-induced respiratory depression in the isolated brainstem-spinal cord preparation suggested a central origin of the phenotype. Task2 activation by reactive oxygen species generated during hypoxia could silence RTN neurons, thus contributing to respiratory depression. These data identify Task2 as a determinant of central O(2) chemoreception and demonstrate that this phenomenon is due to the activity of a small number of neurons located at the ventral medullary surface.
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MESH Headings
- Animals
- Animals, Newborn
- Brain Stem/pathology
- Brain Stem/physiology
- Brain Stem/physiopathology
- Carbon Dioxide/physiology
- Chemoreceptor Cells/pathology
- Chemoreceptor Cells/physiology
- Disease Models, Animal
- Female
- Homeodomain Proteins/genetics
- Homeodomain Proteins/physiology
- Humans
- Hypercapnia/physiopathology
- Hypoxia/physiopathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Mutant Strains
- Oxygen/physiology
- Plethysmography, Whole Body
- Potassium Channels, Tandem Pore Domain/deficiency
- Potassium Channels, Tandem Pore Domain/genetics
- Potassium Channels, Tandem Pore Domain/physiology
- Pregnancy
- Respiratory Center/physiology
- Respiratory Physiological Phenomena
- Sleep Apnea, Central/etiology
- Sleep Apnea, Central/genetics
- Sleep Apnea, Central/physiopathology
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription Factors/physiology
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Affiliation(s)
- Christian Gestreau
- Department of Neurovegetative Physiology, Centre National de la Recherche Scientifique, Université Paul Cézanne, 13397 Marseille, France;
| | - Dirk Heitzmann
- Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany;
- Department of Internal Medicine, Nephrologyand Rheumatology, University of Muenster, 48149 Muenster, Germany;
| | - Joerg Thomas
- Department of Anaesthesiology, University of Ulm, 89075 Ulm, Germany;
| | - Véronique Dubreuil
- Département de Biologie, Ecole Normale Supérieure, Centre National de la Recherche Scientifique, 75005 Paris, France; and
| | - Sascha Bandulik
- Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany;
| | - Markus Reichold
- Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany;
| | - Saïd Bendahhou
- Transport Ionique Aspects Normaux et Pathologiques, Centre National de la Recherche Scientifique, and Faculté des Sciences, Université de Nice Sophia Antipolis, 06108 Nice Cedex, France
| | - Patricia Pierson
- Transport Ionique Aspects Normaux et Pathologiques, Centre National de la Recherche Scientifique, and Faculté des Sciences, Université de Nice Sophia Antipolis, 06108 Nice Cedex, France
| | - Christina Sterner
- Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany;
| | - Julie Peyronnet-Roux
- Department of Neurovegetative Physiology, Centre National de la Recherche Scientifique, Université Paul Cézanne, 13397 Marseille, France;
| | - Chérif Benfriha
- Department of Neurovegetative Physiology, Centre National de la Recherche Scientifique, Université Paul Cézanne, 13397 Marseille, France;
| | - Ines Tegtmeier
- Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany;
| | - Hannah Ehnes
- Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany;
| | - Michael Georgieff
- Department of Anaesthesiology, University of Ulm, 89075 Ulm, Germany;
| | - Florian Lesage
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, and Université de Nice Sophia Antipolis, 06560 Valbonne, France;
| | - Jean-Francois Brunet
- Département de Biologie, Ecole Normale Supérieure, Centre National de la Recherche Scientifique, 75005 Paris, France; and
| | - Christo Goridis
- Département de Biologie, Ecole Normale Supérieure, Centre National de la Recherche Scientifique, 75005 Paris, France; and
| | - Richard Warth
- Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany;
| | - Jacques Barhanin
- Transport Ionique Aspects Normaux et Pathologiques, Centre National de la Recherche Scientifique, and Faculté des Sciences, Université de Nice Sophia Antipolis, 06108 Nice Cedex, France
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44
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Schreiber R, Uliyakina I, Kongsuphol P, Warth R, Mirza M, Martins JR, Kunzelmann K. Expression and function of epithelial anoctamins. J Biol Chem 2010; 285:7838-45. [PMID: 20056604 DOI: 10.1074/jbc.m109.065367] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The calcium-activated chloride channel anoctamin1 (ANO1; TMEM16A) is fundamental for the function of epithelial organs. Mice lacking ANO1 expression exhibit transport defects and a pathology similar to cystic fibrosis. They also show a general defect of epithelial electrolyte transport. Here we analyzed expression of all ten members (ANO1-ANO10) in a broad range of murine tissues and detected predominant expression of ANO1, 6, 7, 8, 9, 10 in epithelial tissues, while ANO2, 3, 4, 5 are common in neuronal and muscle tissues. When expressed in Fisher Rat Thyroid (FTR) cells, all ANO proteins localized to the plasma membrane but only ANO1, 2, 6, and 7 produced Ca(2+)-activated Cl(-) conductance, as analyzed by ATP-induced iodide quenching of YFP fluorescence. In contrast ANO9 and ANO10 suppressed baseline Cl(-) conductance and coexpression of ANO9 with ANO1 inhibited ANO1 activity. Patch clamping of ANO-expressing FRT cells indicated that apart from ANO1 also ANO6 and 10 produced chloride currents, albeit with very different Ca(2+) sensitivity and activation time. We conclude that each tissue expresses a set of anoctamins that form cell- and tissue-specific Ca(2+)-dependent Cl(-) channels.
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Affiliation(s)
- Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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45
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Preston P, Wartosch L, Günzel D, Fromm M, Kongsuphol P, Ousingsawat J, Kunzelmann K, Barhanin J, Warth R, Jentsch TJ. Disruption of the K+ channel beta-subunit KCNE3 reveals an important role in intestinal and tracheal Cl- transport. J Biol Chem 2010; 285:7165-75. [PMID: 20051516 DOI: 10.1074/jbc.m109.047829] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The KCNE3 beta-subunit constitutively opens outwardly rectifying KCNQ1 (Kv7.1) K(+) channels by abolishing their voltage-dependent gating. The resulting KCNQ1/KCNE3 heteromers display enhanced sensitivity to K(+) channel inhibitors like chromanol 293B. KCNE3 was also suggested to modify biophysical properties of several other K(+) channels, and a mutation in KCNE3 was proposed to underlie forms of human periodic paralysis. To investigate physiological roles of KCNE3, we now disrupted its gene in mice. kcne3(-/-) mice were viable and fertile and displayed neither periodic paralysis nor other obvious skeletal muscle abnormalities. KCNQ1/KCNE3 heteromers are present in basolateral membranes of intestinal and tracheal epithelial cells where they might facilitate transepithelial Cl(-) secretion through basolateral recycling of K(+) ions and by increasing the electrochemical driving force for apical Cl(-) exit. Indeed, cAMP-stimulated electrogenic Cl(-) secretion across tracheal and intestinal epithelia was drastically reduced in kcne3(-/-) mice. Because the abundance and subcellular localization of KCNQ1 was unchanged in kcne3(-/-) mice, the modification of biophysical properties of KCNQ1 by KCNE3 is essential for its role in intestinal and tracheal transport. Further, these results suggest KCNE3 as a potential modifier gene in cystic fibrosis.
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Affiliation(s)
- Patricia Preston
- Leibniz-Institut für Molekulare Pharmakologie and Max-Delbrück-Centrum für Molekulare Medizin, 13125 Berlin, Germany
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46
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Feliciangeli SF, Bendahhou S, Tardy MP, Sandoz G, Chatelain FC, Reichold M, Warth R, Barhanin J, Lesage F. Membrane Trafficking Controls K2P1/TWIK1 Channel Expression at the Cell Surface. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.2914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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47
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Feliciangeli S, Tardy MP, Sandoz G, Chatelain FC, Warth R, Barhanin J, Bendahhou S, Lesage F. Potassium channel silencing by constitutive endocytosis and intracellular sequestration. J Biol Chem 2009; 285:4798-805. [PMID: 19959478 DOI: 10.1074/jbc.m109.078535] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Tandem of P domains in a weak inwardly rectifying K(+) channel 1 (TWIK1) is a K(+) channel that produces unusually low levels of current. Replacement of lysine 274 by a glutamic acid (K274E) is associated with stronger currents. This mutation would prevent conjugation of a small ubiquitin modifier peptide to Lys-274, a mechanism proposed to be responsible for channel silencing. However, we found no biochemical evidence of TWIK1 sumoylation, and we showed that the conservative change K274R did not increase current, suggesting that K274E modifies TWIK1 gating through a charge effect. Now we rule out an eventual effect of K274E on TWIK1 trafficking, and we provide convincing evidence that TWIK1 silencing results from its rapid retrieval from the cell surface. TWIK1 is internalized via a dynamin-dependent mechanism and addressed to the recycling endosomal compartment. Mutation of a diisoleucine repeat located in its cytoplasmic C terminus (I293A,I294A) stabilizes TWIK1 at the plasma membrane, resulting in robust currents. The effects of I293A,I294A on channel trafficking and of K274E on channel activity are cumulative, promoting even more currents. Activation of serotoninergic receptor 5-HT(1)R or adrenoreceptor alpha2A-AR stimulates TWIK1 but has no effect on TWIK1I293A,I294A, suggesting that G(i) protein activation is a physiological signal for increasing the number of active channels at the plasma membrane.
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Affiliation(s)
- Sylvain Feliciangeli
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, and Université de Nice Sophia-Antipolis, Sophia-Antipolis, 06560 Valbonne, France
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48
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Grünfeld JP, Scholl UI, Bockenhauer D, Glaudemans B, van Bommel EF, Scheel PJ, Delvaeye M, Choi M, Liu T, Ramaekers VT, Häusler MG, Grimmer J, Tobe SW, Farhi A, Nelson-Williams C, Lifton RP, Feather S, Stanescu HC, Bandulik S, Zdebik AA, Reichold M, Tobin J, Lieberer E, Sterner C, Landoure G, Arora R, Sirimanna T, Thompson D, Cross JH, van't Hoff W, Al Masri O, Tullus K, Yeung S, Anikster Y, Klootwijk E, Hubank M, Dillon MJ, Heitzmann D, Arcos-Burgos M, Knepper MA, Dobbie A, Gahl WA, Warth R, Sheridan E, Kleta R, van der Wijst J, Scola R, Lorenzoni PJ, Heister A, van der Kemp A, Knoers NV, Hoenderop JG, Bindels RJ, Jansen I, Hendriksz TR, Aarnoudse AL, Feeley N, Noris M, De Vriese A, Esmon CT, Esmon NL, Ferrell G, Del-Favero J, Plaisance S, Claes B, Lambrechts D, Remuzzi G, Conway EM. Rare but Relevant Kidney DisordersSeizures, sensorineural deafness, ataxia, mental retardation, and electrolyte imbalance (SeSAME syndrome) caused by mutations in KCNJ10. Proc Natl Acad Sci U S A 106: 5842–5847, 2009Epilepsy, ataxia, sensorineural deafness, tubulopathy, and KCNJ10 mutations. N Engl J Med 360: 1960–1970, 2009A missense mutation in the Kv1.1 voltage-gated potassium channel-encoding gene KCNA1 is linked to human autosomal dominant hypomagnesemia. J Clin Invest 119: 936–942, 2009Idiopathic retroperitoneal fibrosis: Prospective evaluation of incidence and clinicoradiologic presentation. Medicine 88: 193–201, 2009Retroperitoneal fibrosis: The clinical, laboratory, and radiographic presentation. Medicine 88: 202–207, 2009Thrombomodulin mutations in atypical hemolytic-uremic syndrome. N Engl J Med 361: 345–357, 2009. Clin J Am Soc Nephrol 2009. [DOI: 10.2215/cjn.06710909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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49
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Bockenhauer D, Feather S, Stanescu HC, Bandulik S, Zdebik AA, Reichold M, Tobin J, Lieberer E, Sterner C, Landoure G, Arora R, Sirimanna T, Thompson D, Cross JH, van't Hoff W, Al Masri O, Tullus K, Yeung S, Anikster Y, Klootwijk E, Hubank M, Dillon MJ, Heitzmann D, Arcos-Burgos M, Knepper MA, Dobbie A, Gahl WA, Warth R, Sheridan E, Kleta R. Rare but Relevant Kidney Disorders. Clin J Am Soc Nephrol 2009. [DOI: 10.2215/01.cjn.0000927052.57897.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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50
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Lee WK, Reichold M, Edemir B, Ciarimboli G, Warth R, Koepsell H, Thévenod F. Organic cation transporters OCT1, 2, and 3 mediate high-affinity transport of the mutagenic vital dye ethidium in the kidney proximal tubule. Am J Physiol Renal Physiol 2009; 296:F1504-13. [DOI: 10.1152/ajprenal.90754.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The positively charged fluorescent dyes ethidium (Et+) and propidium (Pr2+) are widely used as DNA and necrosis markers. Et+is cytotoxic and mutagenic. The polyspecific organic cation transporters OCT1 (SLC22A1), OCT2 (SLC22A2), and OCT3 (SLC22A3) mediate electrogenic facilitated diffusion of small (≤500 Da) organic cations with broad specificities. In humans, OCT2 mediates basolateral uptake by kidney proximal tubules (PT), whereas in rodents OCT1/2 are involved. In mouse kidney, perfused Et+accumulated predominantly in the S2/S3 segments of the PT, but not Pr2+. In cells stably overexpressing human OCTs (hOCTs), Et+uptake was observed with Kmvalues of 0.8 ± 0.2 μM (hOCT1), 1.7 ± 0.5 μM (hOCT2), and 2.0 ± 0.5 μM (hOCT3), whereas Pr2+was not transported. Accumulation of Et+was inhibited by OCT substrates quinine, 3-methyl-4-phenylpyridinium (MPP+), cimetidine, and tetraethylammonium (TEA+). For hOCT1 and hOCT2, the IC50values for MPP+, TEA+, and cimetidine were higher than for inhibition of previously tested transported substrates. For hOCT2, the inhibition of Et+uptake by MPP+and cimetidine was shown to be competitive. Et+also inhibited transport of 0.1 μM [3H]MPP+by all hOCT isoforms with IC50values between 0.4 and 1.3 μM, and the inhibition of hOCT1-mediated uptake of MPP+by Et+was competitive. In Oct1/2−/−mice, Et+uptake in the PT was almost abolished. The data demonstrate that Et+is taken up avidly by the PT, which is mediated by OCT1 and/or OCT2. Considering the high affinity of OCTs for Et+and their strong expression in various organs, strict safety guidelines for Et+handling should be reinforced.
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