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Jung HJ, Pham TD, Su XT, Grigore TV, Hoenderop JG, Olauson H, Wall SM, Ellison DH, Welling PA, Al-Qusairi L. Klotho is highly expressed in the chief sites of regulated potassium secretion, and it is stimulated by potassium intake. Sci Rep 2024; 14:10740. [PMID: 38729987 PMCID: PMC11087591 DOI: 10.1038/s41598-024-61481-w] [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: 10/27/2023] [Accepted: 05/06/2024] [Indexed: 05/12/2024] Open
Abstract
Klotho regulates many pathways in the aging process, but it remains unclear how it is physiologically regulated. Because Klotho is synthesized, cleaved, and released from the kidney; activates the chief urinary K+ secretion channel (ROMK) and stimulates urinary K+ secretion, we explored if Klotho protein is regulated by dietary K+ and the potassium-regulatory hormone, Aldosterone. Klotho protein along the nephron was evaluated in humans and in wild-type (WT) mice; and in mice lacking components of Aldosterone signaling, including the Aldosterone-Synthase KO (AS-KO) and the Mineralocorticoid-Receptor KO (MR-KO) mice. We found the specific cells of the distal nephron in humans and mice that are chief sites of regulated K+ secretion have the highest Klotho protein expression along the nephron. WT mice fed K+-rich diets increased Klotho expression in these cells. AS-KO mice exhibit normal Klotho under basal conditions but could not upregulate Klotho in response to high-K+ intake in the K+-secreting cells. Similarly, MR-KO mice exhibit decreased Klotho protein expression. Together, i) Klotho is highly expressed in the key sites of regulated K+ secretion in humans and mice, ii) In mice, K+-rich diets increase Klotho expression specifically in the potassium secretory cells of the distal nephron, iii) Aldosterone signaling is required for Klotho response to high K+ intake.
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Affiliation(s)
- Hyun Jun Jung
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Truyen D Pham
- Department of Nephrology, Emory University School of Medicine, Atlanta, GA, USA
| | - Xiao-Tong Su
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, USA
| | - Teodora Veronica Grigore
- Department of Medical BioSciences, Radboud Research Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Medical BioSciences, Radboud Research Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hannes Olauson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Susan M Wall
- Department of Nephrology, Emory University School of Medicine, Atlanta, GA, USA
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, USA
| | - Paul A Welling
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lama Al-Qusairi
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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2
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Hoogstraten CA, Hoenderop JG, de Baaij JHF. Mitochondrial Dysfunction in Kidney Tubulopathies. Annu Rev Physiol 2024; 86:379-403. [PMID: 38012047 DOI: 10.1146/annurev-physiol-042222-025000] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Mitochondria play a key role in kidney physiology and pathology. They produce ATP to fuel energy-demanding water and solute reabsorption processes along the nephron. Moreover, mitochondria contribute to cellular health by the regulation of autophagy, (oxidative) stress responses, and apoptosis. Mitochondrial abundance is particularly high in cortical segments, including proximal and distal convoluted tubules. Dysfunction of the mitochondria has been described for tubulopathies such as Fanconi, Gitelman, and Bartter-like syndromes and renal tubular acidosis. In addition, mitochondrial cytopathies often affect renal (tubular) tissues, such as in Kearns-Sayre and Leigh syndromes. Nevertheless, the mechanisms by which mitochondrial dysfunction results in renal tubular diseases are only scarcely being explored. This review provides an overview of mitochondrial dysfunction in the development and progression of kidney tubulopathies. Furthermore, it emphasizes the need for further mechanistic investigations to identify links between mitochondrial function and renal electrolyte reabsorption.
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Affiliation(s)
- Charlotte A Hoogstraten
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands;
| | - Joost G Hoenderop
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands;
| | - Jeroen H F de Baaij
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands;
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3
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Yousef Yengej FA, Pou Casellas C, Ammerlaan CME, Olde Hanhof CJA, Dilmen E, Beumer J, Begthel H, Meeder EMG, Hoenderop JG, Rookmaaker MB, Verhaar MC, Clevers H. Tubuloid differentiation to model the human distal nephron and collecting duct in health and disease. Cell Rep 2024; 43:113614. [PMID: 38159278 DOI: 10.1016/j.celrep.2023.113614] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/09/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024] Open
Abstract
Organoid technology is rapidly gaining ground for studies on organ (patho)physiology. Tubuloids are long-term expanding organoids grown from adult kidney tissue or urine. The progenitor state of expanding tubuloids comes at the expense of differentiation. Here, we differentiate tubuloids to model the distal nephron and collecting ducts, essential functional parts of the kidney. Differentiation suppresses progenitor traits and upregulates genes required for function. A single-cell atlas reveals that differentiation predominantly generates thick ascending limb and principal cells. Differentiated human tubuloids express luminal NKCC2 and ENaC capable of diuretic-inhibitable electrolyte uptake and enable disease modeling as demonstrated by a lithium-induced tubulopathy model. Lithium causes hallmark AQP2 loss, induces proliferation, and upregulates inflammatory mediators, as seen in vivo. Lithium also suppresses electrolyte transport in multiple segments. In conclusion, this tubuloid model enables modeling of the human distal nephron and collecting duct in health and disease and provides opportunities to develop improved therapies.
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Affiliation(s)
- Fjodor A Yousef Yengej
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Carla Pou Casellas
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Carola M E Ammerlaan
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Charlotte J A Olde Hanhof
- Department of Medical BioSciences, Radboud Institute for Medical Innovation, 6525 GA Nijmegen, the Netherlands
| | - Emre Dilmen
- Department of Medical BioSciences, Radboud Institute for Medical Innovation, 6525 GA Nijmegen, the Netherlands
| | - Joep Beumer
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW, 3584 CT Utrecht, the Netherlands; Institute of Human Biology, Roche Pharma Research and Early Development, 4058 Basel, Switzerland
| | - Harry Begthel
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW, 3584 CT Utrecht, the Netherlands
| | - Elise M G Meeder
- Department of Psychiatry, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Joost G Hoenderop
- Department of Medical BioSciences, Radboud Institute for Medical Innovation, 6525 GA Nijmegen, the Netherlands
| | - Maarten B Rookmaaker
- Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands.
| | - Hans Clevers
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute-KNAW, 3584 CT Utrecht, the Netherlands.
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4
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Zuidscherwoude M, van Goor MK, Roig SR, Thijssen N, van Erp M, Fransen J, van der Wijst J, Hoenderop JG. Functional basis for calmodulation of the TRPV5 calcium channel. J Physiol 2023; 601:859-878. [PMID: 36566502 DOI: 10.1113/jp282952] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/06/2022] [Indexed: 12/26/2022] Open
Abstract
Within the transient receptor potential (TRP) superfamily of ion channels, TRPV5 is a highly Ca2+ -selective channel important for active reabsorption of Ca2+ in the kidney. Its channel activity is controlled by a negative feedback mechanism involving calmodulin (CaM) binding. Combining advanced microscopy techniques and biochemical assays, this study characterized the dynamic lobe-specific CaM regulation. We demonstrate for the first time that functional (full-length) TRPV5 interacts with CaM in the absence of Ca2+ , and this interaction is intensified at increasing Ca2+ concentrations sensed by the CaM C-lobe that achieves channel pore blocking. Channel inactivation occurs without requiring CaM N-lobe calcification. Moreover, we show a Ca2+ -dependent binding stoichiometry at the single channel level. In conclusion, our study proposes a new model for CaM-dependent regulation - calmodulation - of this uniquely Ca2+ -selective TRP channel TRPV5 that involves apoCaM interaction and lobe-specific actions, which may be of significant physiological relevance given its role as gatekeeper of Ca2+ transport in the kidney. KEY POINTS: The renal Ca2+ channel TRPV5 is an important player in maintenance of the body's Ca2+ homeostasis. Activity of TRPV5 is controlled by a negative feedback loop that involves calmodulin (CaM), a protein with two Ca2+ -binding lobes. We investigated the dynamics of the interaction between TRPV5 and CaM with advanced fluorescence microscopy techniques. Our data support a new model for CaM-dependent regulation of TRPV5 channel activity with CaM lobe-specific actions and demonstrates Ca2+ -dependent binding stoichiometries. This study improves our understanding of the mechanism underlying fast channel inactivation, which is physiologically relevant given the gatekeeper function of TRPV5 in Ca2+ reabsorption in the kidney.
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Affiliation(s)
- Malou Zuidscherwoude
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mark K van Goor
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sara R Roig
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Imaging Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Niky Thijssen
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Merijn van Erp
- Radboudumc Technology Centre Microscopy, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jack Fransen
- Radboudumc Technology Centre Microscopy, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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5
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Megen WH, Waes CR, Peters DJ, Wijst J, Hoenderop JG. Effects of flow and polycystin‐1 dysfunction on ATP release in the inner medullary collecting duct of the kidney. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wouter H. Megen
- PhysiologyRadboud Institute for Molecular Life Sciences, RadboudumcNijmegen
| | - Charlotte R. Waes
- PhysiologyRadboud Institute for Molecular Life Sciences, RadboudumcNijmegen
| | | | - Jenny Wijst
- PhysiologyRadboud Institute for Molecular Life Sciences, RadboudumcNijmegen
| | - Joost G. Hoenderop
- PhysiologyRadboud Institute for Molecular Life Sciences, RadboudumcNijmegen
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6
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Olde Hanhof CJA, Yousef Yengej FA, Rookmaaker MB, Verhaar MC, van der Wijst J, Hoenderop JG. Modeling Distal Convoluted Tubule (Patho)Physiology: An Overview of Past Developments and an Outlook Toward the Future. Tissue Eng Part C Methods 2021; 27:200-212. [PMID: 33544049 DOI: 10.1089/ten.tec.2020.0345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 12/26/2022] Open
Abstract
The kidneys are essential for maintaining electrolyte homeostasis. Blood electrolyte composition is controlled by active reabsorption and secretion processes in dedicated segments of the kidney tubule. Specifically, the distal convoluted tubule (DCT) and connecting tubule are important for regulating the final excretion of sodium, magnesium, and calcium. Studies unravelling the specific function of these segments have greatly improved our understanding of DCT (patho)physiology. Over the years, experimental models used to study the DCT have changed and the field has advanced from early dissection studies with rats and rabbits to the use of various transgenic mouse models. Developments in dissection techniques and cell culture methods have resulted in immortalized mouse DCT cell lines and made it possible to specifically obtain DCT fragments for ex vivo studies. However, we still do not fully understand the complex (patho)physiology of this segment and there is need for advanced human DCT models. Recently, kidney organoids and tubuloids have emerged as new complex cell models that provide excellent opportunities for physiological studies, disease modeling, drug discovery, and even personalized medicine in the future. This review presents an overview of cell models used to study the DCT and provides an outlook on kidney organoids and tubuloids as model for DCT (patho)physiology. Impact statement This study provides a detailed overview of past and future developments on cell models used to study kidney (patho)physiology and specifically the distal convoluted tubule (DCT) segment. Hereby, we highlight the need for an advanced human cell model of this segment and summarize recent advances in the field of kidney organoids and tubuloids with a focus on DCT properties. The findings reported in this review are significant for future developments toward an advanced human model of the DCT that will help to increase our understanding of DCT (patho)physiology.
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Affiliation(s)
- Charlotte J A Olde Hanhof
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Fjodor A Yousef Yengej
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, Utrecht, The Netherlands.,Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maarten B Rookmaaker
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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7
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van der Wijst J, van Goor MK, Schreuder MF, Hoenderop JG. TRPV5 in renal tubular calcium handling and its potential relevance for nephrolithiasis. Kidney Int 2019; 96:1283-1291. [PMID: 31471161 DOI: 10.1016/j.kint.2019.05.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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: 03/15/2019] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 10/26/2022]
Abstract
Nephrolithiasis or renal stone disease is an increasingly common problem, and its relatively high recurrence rate demands better treatment options. The majority of patients with nephrolithiasis have stones that contain calcium (Ca2+), which develop upon "supersaturation" of the urine with insoluble Ca2+ salts; hence processes that influence the delivery and renal handling of Ca2+ may influence stone formation. Idiopathic hypercalciuria is indeed frequently observed in patients with kidney stones that contain Ca2+. Genetic screens of nephrolithiasis determinants have identified an increasing number of gene candidates, most of which are involved in renal Ca2+ handling. This review provides an outline of the current knowledge regarding genetics of nephrolithiasis and will mainly focus on the epithelial Ca2+ channel transient receptor potential vanilloid 5 (TRPV5), an important player in Ca2+ homeostasis. Being a member of the TRP family of ion channels, TRPV5 is currently part of a revolution in structural biology. Recent technological breakthroughs in the cryo-electron microscopy field, combined with improvements in biochemical sample preparation, have resulted in high-resolution 3-dimensional structural models of integral membrane proteins, including TRPV5. These models currently are being used to explore the proteins' structure-function relationship, elucidate the molecular mechanisms of channel regulation, and study the putative effects of disease variants. Combined with other multidisciplinary approaches, this approach may open an avenue toward better understanding of the pathophysiological mechanisms involved in hypercalciuria and stone formation, and ultimately it may facilitate prevention of stone recurrence through the development of effective drugs.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, the Netherlands
| | - Mark K van Goor
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, the Netherlands
| | - Michiel F Schreuder
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, the Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, the Netherlands.
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8
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Adema AY, de Roij van Zuijdewijn CLM, Hoenderop JG, de Borst MH, Ter Wee PM, Heijboer AC, Vervloet MG. Influence of exogenous growth hormone administration on circulating concentrations of α-klotho in healthy and chronic kidney disease subjects: a prospective, single-center open case-control pilot study. BMC Nephrol 2018; 19:327. [PMID: 30442108 PMCID: PMC6238285 DOI: 10.1186/s12882-018-1114-z] [Citation(s) in RCA: 3] [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: 11/06/2017] [Accepted: 10/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The CKD-associated decline in soluble α-Klotho (α-Klotho) levels is considered detrimental. Some studies suggest a direct induction of α-Klotho concentrations by growth hormone (GH). In the present study, the effect of exogenous GH administration on α-Klotho concentrations in a clinical cohort with mild chronic kidney disease (CKD) and healthy subjects was studied. METHODS A prospective, single-center open case-control pilot study was performed involving 8 patients with mild CKD and 8 healthy controls matched for age and sex. All participants received subcutaneous GH injections (Genotropin®, 20 mcg/kg/day) for 7 consecutive days. α-Klotho concentrations were measured at baseline, after 7 days of therapy and 1 week after the intervention was stopped. RESULTS α-Klotho concentrations were not different between CKD-patients and healthy controls at baseline (554 (388-659) vs. 547 (421-711) pg/mL, P = 0.38). Overall, GH therapy increased α-Klotho concentrations from 554 (405-659) to 645 (516-754) pg/mL, P < 0.05). This was accompanied by an increase of IGF-1 concentrations from 26.8 ± 5.0 nmol/L to 61.7 ± 17.7 nmol/L (P < 0.05). GH therapy induced a trend toward increased α-Klotho concentrations both in the CKD group (554 (388-659) to 591 (358-742) pg/mL (P = 0.19)) and the healthy controls (547 (421-711) pg/mL to 654 (538-754) pg/mL (P = 0.13)). The change in α-Klotho concentration was not different for both groups (P for interaction = 0.71). α-Klotho concentrations returned to baseline levels within one week after the treatment (P < 0.05). CONCLUSIONS GH therapy increases α-Klotho concentrations in subjects with normal renal function or stage 3 CKD. A larger follow-up study is needed to determine whether the effect size is different between both groups or in patients with more severe CKD. TRIAL REGISTRATION This trial is registered in EudraCT ( 2013-003354-24 ).
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Affiliation(s)
- Aaltje Y Adema
- Department of Nephrology, VU University Medical Center, De Boelelaan 1117, 1081, HV, Amsterdam, The Netherlands
| | | | - Joost G Hoenderop
- Department of Physiology, Radboud University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Martin H de Borst
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Piet M Ter Wee
- Department of Nephrology, VU University Medical Center, De Boelelaan 1117, 1081, HV, Amsterdam, The Netherlands
| | - Annemieke C Heijboer
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Marc G Vervloet
- Department of Nephrology, VU University Medical Center, De Boelelaan 1117, 1081, HV, Amsterdam, The Netherlands. .,Amsterdam Cardiovascular Sciences (ACS), Amsterdam, The Netherlands.
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9
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Verkaik M, Juni RP, van Loon EPM, van Poelgeest EM, Kwekkeboom RFJ, Gam Z, Richards WG, Ter Wee PM, Hoenderop JG, Eringa EC, Vervloet MG. FGF23 impairs peripheral microvascular function in renal failure. Am J Physiol Heart Circ Physiol 2018; 315:H1414-H1424. [PMID: 30028196 DOI: 10.1152/ajpheart.00272.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [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] [Indexed: 11/22/2022]
Abstract
Cardiovascular diseases account for ~50% of mortality in patients with chronic kidney disease (CKD). Fibroblast growth factor 23 (FGF23) is independently associated with endothelial dysfunction and cardiovascular mortality. We hypothesized that CKD impairs microvascular endothelial function and that this can be attributed to FGF23. Mice were subjected to partial nephrectomy (5/6Nx) or sham surgery. To evaluate the functional role of FGF23, non-CKD mice received FGF23 injections and CKD mice received FGF23-blocking antibodies after 5/6Nx surgery. To examine microvascular function, myocardial perfusion in vivo and vascular function of gracilis resistance arteries ex vivo were assessed in mice. 5/6Nx surgery blunted ex vivo vasodilator responses to acetylcholine, whereas responses to sodium nitroprusside or endothelin were normal. In vivo FGF23 injections in non-CKD mice mimicked this endothelial defect, and FGF23 antibodies in 5/6Nx mice prevented endothelial dysfunction. Stimulation of microvascular endothelial cells with FGF23 in vitro did not induce ERK phosphorylation. Increased plasma asymmetric dimethylarginine concentrations were increased by FGF23 and strongly correlated with endothelial dysfunction. Increased FGF23 concentration did not mimic impaired endothelial function in the myocardium of 5/6Nx mice. In conclusion, impaired peripheral endothelium-dependent vasodilatation in 5/6Nx mice is mediated by FGF23 and can be prevented by blocking FGF23. These data corroborate FGF23 as an important target to combat cardiovascular disease in CKD. NEW & NOTEWORTHY In the present study, we provide the first evidence that fibroblast growth factor 23 (FGF23) is a cause of peripheral endothelial dysfunction in a model of early chronic kidney disease (CKD) and that endothelial dysfunction in CKD can be prevented by blockade of FGF23. This pathological effect on endothelial cells was induced by long-term exposure of physiological levels of FGF23. Mechanistically, increased plasma asymmetric dimethylarginine concentrations were strongly associated with this endothelial dysfunction in CKD and were increased by FGF23.
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Affiliation(s)
- Melissa Verkaik
- Department of Nephrology and Institute for Cardiovascular Research VU, VU University Medical Center , Amsterdam , The Netherlands
| | - Rio P Juni
- Department of Physiology, Institute for Cardiovascular Research VU, VU University Medical Center , Amsterdam , The Netherlands
| | - Ellen P M van Loon
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Erik M van Poelgeest
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Rick F J Kwekkeboom
- Department of Physiology, Institute for Cardiovascular Research VU, VU University Medical Center , Amsterdam , The Netherlands
| | - Zeineb Gam
- Department of Physiology, Institute for Cardiovascular Research VU, VU University Medical Center , Amsterdam , The Netherlands
| | | | - Pieter M Ter Wee
- Department of Nephrology and Institute for Cardiovascular Research VU, VU University Medical Center , Amsterdam , The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Etto C Eringa
- Department of Physiology, Institute for Cardiovascular Research VU, VU University Medical Center , Amsterdam , The Netherlands
| | - Marc G Vervloet
- Department of Nephrology and Institute for Cardiovascular Research VU, VU University Medical Center , Amsterdam , The Netherlands
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10
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Fedecostante M, Westphal KGC, Buono MF, Sanchez Romero N, Wilmer MJ, Kerkering J, Baptista PM, Hoenderop JG, Masereeuw R. Recellularized Native Kidney Scaffolds as a Novel Tool in Nephrotoxicity Screening. Drug Metab Dispos 2018; 46:1338-1350. [PMID: 29980578 DOI: 10.1124/dmd.118.080721] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/28/2018] [Indexed: 12/15/2022] Open
Abstract
Drug-induced kidney injury in medicinal compound development accounts for over 20% of clinical trial failures and involves damage to different nephron segments, mostly the proximal tubule. Yet, currently applied cell models fail to reliably predict nephrotoxicity; neither are such models easy to establish. Here, we developed a novel three-dimensional (3D) nephrotoxicity platform on the basis of decellularized rat kidney scaffolds (DS) recellularized with conditionally immortalized human renal proximal tubule epithelial cells overexpressing the organic anion transporter 1 (ciPTEC-OAT1). A 5-day SDS-based decellularization protocol was used to generate DS, of which 100-μm slices were cut and used for cell seeding. After 8 days of culturing, recellularized scaffolds (RS) demonstrated 3D-tubule formation along with tubular epithelial characteristics, including drug transporter function. Exposure of RS to cisplatin (CDDP), tenofovir (TFV), or cyclosporin A (CsA) as prototypical nephrotoxic drugs revealed concentration-dependent reduction in cell viability, as assessed by PrestoBlue and Live/Dead staining assays. This was most probably attributable to specific uptake of CDDP by the organic cation transporter 2 (OCT2), TFV through organic anion transporter 1 (OAT1), and CsA competing for P-glycoprotein-mediated efflux. Compared with 2D cultures, RS showed an increased sensitivity to cisplatin and tenofovir toxicity after 24-hour exposure (9 and 2.2 fold, respectively). In conclusion, we developed a physiologically relevant 3D nephrotoxicity screening platform that could be a novel tool in drug development.
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Affiliation(s)
- Michele Fedecostante
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Koen G C Westphal
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Michele F Buono
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Natalia Sanchez Romero
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Martijn J Wilmer
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Janis Kerkering
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Pedro Miguel Baptista
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Joost G Hoenderop
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands (M.F., K.G.C.W., M.F.B., N.S.R., R.M.); Aragon's Health Science Institutes (IACS), Zaragoza, Spain (N.S.M.); Departments of Pharmacology and Toxicology (M.J.W., J.K.) and Physiology (J.G.H.), Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain (P.M.B.); Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Madrid, Spain (P.M.B.); Jiménez Díaz Foundation Health Research Institute, Madrid, Spain (P.M.B.); and Department of Biomedical and Aerospace Engineering, Carlos III University of Madrid, Spain (P.M.B.)
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11
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de Jong MA, Mirkovic K, Mencke R, Hoenderop JG, Bindels RJ, Vervloet MG, Hillebrands JL, van den Born J, Navis G, de Borst MH. Fibroblast growth factor 23 modifies the pharmacological effects of angiotensin receptor blockade in experimental renal fibrosis. Nephrol Dial Transplant 2017; 32:73-80. [PMID: 27220755 DOI: 10.1093/ndt/gfw105] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [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: 12/15/2015] [Accepted: 03/31/2016] [Indexed: 01/17/2023] Open
Abstract
Background Blockade of the renin-angiotensin-aldosterone system (RAAS) retards progression of chronic kidney disease. Yet, in many patients, the renoprotective effect is incomplete. A high circulating level of the phosphaturic hormone fibroblast growth factor 23 is associated with an impaired response to RAAS blockade-based therapy in clinical studies. Therefore, we addressed whether administration of recombinant fibroblast growth factor 23 (FGF23) interferes with the efficacy of angiotensin receptor blocker (ARB) treatment in a mouse model of renal fibrosis [unilateral ureteral obstruction (UUO)]. Methods UUO mice were treated with losartan (100 mg/L in drinking water), recombinant FGF23 (160 ng/kg i.p. twice daily), their combination or vehicle ( n = 10 per group). Seven days after the UUO procedure, kidney tissue was analyzed for markers of RAAS activity, inflammation and fibrosis using real-time PCR and immunohistochemistry. Results In the contralateral (non-affected) kidneys of ARB-treated UUO mice, administration of FGF23 reversed the induction of renin, ACE, ACE2 and AT1 receptor mRNA expression, suggesting interference with the physiological response to RAAS blockade by FGF23. Furthermore, recombinant FGF23 infusion prevented ARB-induced klotho upregulation in contralateral kidneys. In the UUO kidneys, klotho was majorly reduced in all groups. Pro-inflammatory gene expression (MCP-1, TNF-α) induced in UUO kidneys was reduced by ARB treatment; this anti-inflammatory effect was reversed by FGF23. In contrast, ARB-induced reduction of (pre-)fibrotic gene expression was not reversed by FGF23. Conclusions Our findings show pharmacological interaction between exogenous FGF23 and losartan, thus serving as a proof of principle for crosstalk between the FGF23-klotho axis and RAAS.
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Affiliation(s)
- Maarten A de Jong
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Katarina Mirkovic
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rik Mencke
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J Bindels
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marc G Vervloet
- Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Jan-Luuk Hillebrands
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jacob van den Born
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Gerjan Navis
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Martin H de Borst
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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12
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Sonneveld R, Hoenderop JG, Isidori AM, Henique C, Dijkman HB, Berden JH, Tharaux PL, van der Vlag J, Nijenhuis T. Sildenafil Prevents Podocyte Injury via PPAR- γ-Mediated TRPC6 Inhibition. J Am Soc Nephrol 2016; 28:1491-1505. [PMID: 27895156 DOI: 10.1681/asn.2015080885] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/02/2016] [Indexed: 02/06/2023] Open
Abstract
Transient receptor potential channel C6 (TRPC6) gain-of-function mutations and increased TRPC6 expression in podocytes induce glomerular injury and proteinuria. Sildenafil reduces TRPC6 expression and activity in nonrenal cell types, although the mechanism is unknown. Peroxisome proliferator-activated receptor γ (PPAR-γ) is a downstream target of sildenafil in the cyclic guanosine monophosphate (cGMP)-activated protein kinase G (PKG) axis. PPAR-γ agonists, like pioglitazone, appear antiproteinuric. We hypothesized that sildenafil inhibits TRPC6 expression in podocytes through PPAR-γ-dependent mechanisms, thereby counteracting podocyte injury and proteinuria. Treatment with sildenafil, the cGMP derivative 8-bromoguanosine 3',5'-cyclic monophosphate sodium salt (8-Br-cGMP), or pioglitazone dose-dependently downregulated podocyte injury-induced TRPC6 expression in vitro Knockdown or application of antagonists of PKG or PPAR-γ enhanced TRPC6 expression in podocytes and counteracted effects of sildenafil and 8-Br-cGMP. We observed similar effects on TRPC6 promoter activity and TRPC6-dependent calcium influx. Chromatin immunoprecipitation showed PPAR-γ binding to the TRPC6 promoter. Sildenafil or pioglitazone treatment prevented proteinuria and the increased TRPC6 expression in rats with adriamycin-induced nephropathy and mice with hyperglycemia-induced renal injury. Rats receiving PPAR-γ antagonists displayed proteinuria and increased podocyte TRPC6 expression, as did podocyte-specific PPAR-γ knockout mice, which were more sensitive to adriamycin and not protected by sildenafil. Thus, sildenafil ameliorates podocyte injury and prevents proteinuria through cGMP- and PKG-dependent binding of PPAR-γ to the TRPC6 promoter, which inhibits TRPC6 promoter activity, expression, and activity. Because sildenafil is approved for clinical use, our results suggest that additional clinical study of its antiproteinuric effect in glomerular disease is warranted.
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Affiliation(s)
| | | | - Andrea M Isidori
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Carole Henique
- Paris Cardiovascular Centre, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Paris Cité, Université Paris Descartes, Paris, France; and
| | - Henry B Dijkman
- Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Pierre-Louis Tharaux
- Paris Cardiovascular Centre, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Paris Cité, Université Paris Descartes, Paris, France; and.,Service de Néphrologie, Hôpital Européen Georges Pompidou, Paris, France
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13
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Adema AY, van Ittersum FJ, Hoenderop JG, de Borst MH, Nanayakkara PW, Ter Wee PM, Heijboer AC, Vervloet MG. Reduction of Oxidative Stress in Chronic Kidney Disease Does Not Increase Circulating α-Klotho Concentrations. PLoS One 2016; 11:e0144121. [PMID: 26807718 PMCID: PMC4725669 DOI: 10.1371/journal.pone.0144121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/13/2015] [Indexed: 11/18/2022] Open
Abstract
The CKD-associated decline in soluble α-Klotho levels is considered detrimental. Some in vitro and in vivo animal studies have shown that anti-oxidant therapy can upregulate the expression of α-Klotho in the kidney. We examined the effect of anti-oxidant therapy on α-Klotho concentrations in a clinical cohort with mild tot moderate chronic kidney disease (CKD). We performed a post-hoc analysis of a prospective randomized trial involving 62 patients with mild to moderate CKD (the ATIC study), all using an angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) for 12 months. On top of that, the intervention group received anti-oxidative therapy consisting of the combination of pravastatin (40 mg/d) and vitamin E (α-tocopherol acetate, 300 mg/d) while the placebo was not treated with anti-oxidants. α-Klotho concentrations were measured at baseline and after 12 months of anti-oxidant therapy. Data were analysed using T-tests and Generalized Estimating Equations, adjusting for potential confounders such as vitamin D, parathyroid hormone, fibroblast-growth-factor 23 (FGF23) and eGFR. The cohort existed of 62 patients with an eGFR (MDRD) of 35 ± 14 ml/min/1.72m2, 34 were male and mean age was 53.0 ± 12.5 years old. Anti-oxidative therapy did successfully reduce oxLDL and LDL concentrations (P <0.001). α-Klotho concentrations did not change in patients receiving either anti-oxidative therapy (476.9 ± 124.3 to 492.7 ± 126.3 pg/mL, P = 0.23) nor in those receiving placebo 483.2 ± 142.5 to 489.6 ± 120.3 pg/mL, P = 0.62). Changes in α-Klotho concentrations were not different between both groups (p = 0.62). No evidence was found that anti-oxidative therapy affected α-Klotho concentrations in patients with mild-moderate CKD.
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Affiliation(s)
- Aaltje Y. Adema
- Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Joost G. Hoenderop
- Department of Physiology, Radboud university medical center Nijmegen, The Netherlands
| | - Martin H. de Borst
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Prabath W. Nanayakkara
- Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Piet M. Ter Wee
- Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Annemieke C. Heijboer
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Marc G. Vervloet
- Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
- Institute for Cardiovascular Research VU (ICaR-VU), Amsterdam. The Netherlands
- * E-mail:
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14
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Jansen J, De Napoli IE, Fedecostante M, Schophuizen CMS, Chevtchik NV, Wilmer MJ, van Asbeck AH, Croes HJ, Pertijs JC, Wetzels JFM, Hilbrands LB, van den Heuvel LP, Hoenderop JG, Stamatialis D, Masereeuw R. Human proximal tubule epithelial cells cultured on hollow fibers: living membranes that actively transport organic cations. Sci Rep 2015; 5:16702. [PMID: 26567716 PMCID: PMC4644946 DOI: 10.1038/srep16702] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 10/05/2015] [Indexed: 11/11/2022] Open
Abstract
The bioartificial kidney (BAK) aims at improving dialysis by developing ‘living membranes’ for cells-aided removal of uremic metabolites. Here, unique human conditionally immortalized proximal tubule epithelial cell (ciPTEC) monolayers were cultured on biofunctionalized MicroPES (polyethersulfone) hollow fiber membranes (HFM) and functionally tested using microfluidics. Tight monolayer formation was demonstrated by abundant zonula occludens-1 (ZO-1) protein expression along the tight junctions of matured ciPTEC on HFM. A clear barrier function of the monolayer was confirmed by limited diffusion of FITC-inulin. The activity of the organic cation transporter 2 (OCT2) in ciPTEC was evaluated in real-time using a perfusion system by confocal microscopy using 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP+) as a fluorescent substrate. Initial ASP+ uptake was inhibited by a cationic uremic metabolites mixture and by the histamine H2-receptor antagonist, cimetidine. In conclusion, a ‘living membrane’ of renal epithelial cells on MicroPES HFM with demonstrated active organic cation transport was successfully established as a first step in BAK engineering.
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Affiliation(s)
- J Jansen
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Physiology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud university medical center, Nijmegen, The Netherlands
| | - I E De Napoli
- Department of Biomaterials Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, The Netherlands
| | - M Fedecostante
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Physiology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud university medical center, Nijmegen, The Netherlands
| | - C M S Schophuizen
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Physiology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud university medical center, Nijmegen, The Netherlands
| | - N V Chevtchik
- Department of Biomaterials Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, The Netherlands
| | - M J Wilmer
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - A H van Asbeck
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - H J Croes
- Department of Cell Biology, Radboud university medical center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - J C Pertijs
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - J F M Wetzels
- Department of Nephrology, Radboud university medical center, Nijmegen, The Netherlands
| | - L B Hilbrands
- Department of Nephrology, Radboud university medical center, Nijmegen, The Netherlands
| | - L P van den Heuvel
- Department of Pediatrics, Radboud university medical center, Nijmegen, The Netherlands.,Department of Pediatric Nephrology &Growth and Regeneration, Catholic University Leuven, Leuven, Belgium
| | - J G Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - D Stamatialis
- Department of Biomaterials Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, The Netherlands
| | - R Masereeuw
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Div. Pharmacology, Department of Pharmaceutical Sciences, Utrecht University, The Netherlands
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15
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Pulskens WP, Verkaik M, Sheedfar F, van Loon EP, van de Sluis B, Vervloet MG, Hoenderop JG, Bindels RJ. Deregulated Renal Calcium and Phosphate Transport during Experimental Kidney Failure. PLoS One 2015; 10:e0142510. [PMID: 26566277 PMCID: PMC4643984 DOI: 10.1371/journal.pone.0142510] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 10/22/2015] [Indexed: 12/17/2022] Open
Abstract
Impaired mineral homeostasis and inflammation are hallmarks of chronic kidney disease (CKD), yet the underlying mechanisms of electrolyte regulation during CKD are still unclear. Here, we applied two different murine models, partial nephrectomy and adenine-enriched dietary intervention, to induce kidney failure and to investigate the subsequent impact on systemic and local renal factors involved in Ca(2+) and Pi regulation. Our results demonstrated that both experimental models induce features of CKD, as reflected by uremia, and elevated renal neutrophil gelatinase-associated lipocalin (NGAL) expression. In our model kidney failure was associated with polyuria, hypercalcemia and elevated urinary Ca(2+) excretion. In accordance, CKD augmented systemic PTH and affected the FGF23-αklotho-vitamin-D axis by elevating circulatory FGF23 levels and reducing renal αklotho expression. Interestingly, renal FGF23 expression was also induced by inflammatory stimuli directly. Renal expression of Cyp27b1, but not Cyp24a1, and blood levels of 1,25-dihydroxy vitamin D3 were significantly elevated in both models. Furthermore, kidney failure was characterized by enhanced renal expression of the transient receptor potential cation channel subfamily V member 5 (TRPV5), calbindin-D28k, and sodium-dependent Pi transporter type 2b (NaPi2b), whereas the renal expression of sodium-dependent Pi transporter type 2a (NaPi2a) and type 3 (PIT2) were reduced. Together, our data indicates two different models of experimental kidney failure comparably associate with disturbed FGF23-αklotho-vitamin-D signalling and a deregulated electrolyte homeostasis. Moreover, this study identifies local tubular, possibly inflammation- or PTH- and/or FGF23-associated, adaptive mechanisms, impacting on Ca(2+)/Pi homeostasis, hence enabling new opportunities to target electrolyte disturbances that emerge as a consequence of CKD development.
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Affiliation(s)
- Wilco P. Pulskens
- Dept. of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
- Dept. of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Melissa Verkaik
- Dept. of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Fareeba Sheedfar
- Dept. of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ellen P. van Loon
- Dept. of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bart van de Sluis
- Dept. of Pediatrics, Molecular Genetics Section, University Medical Center Groningen, Groningen, The Netherlands
| | - Mark G. Vervloet
- Dept. of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Joost G. Hoenderop
- Dept. of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J. Bindels
- Dept. of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
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16
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Mutsaers HA, Caetano-Pinto P, Seegers AE, Dankers AC, van den Broek PH, Wetzels JF, van den Brand JA, van den Heuvel LP, Hoenderop JG, Wilmer MJ, Masereeuw R. Proximal tubular efflux transporters involved in renal excretion of p-cresyl sulfate and p-cresyl glucuronide: Implications for chronic kidney disease pathophysiology. Toxicol In Vitro 2015. [DOI: 10.1016/j.tiv.2015.07.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Mencke R, Harms G, Mirković K, Struik J, Van Ark J, Van Loon E, Verkaik M, De Borst MH, Zeebregts CJ, Hoenderop JG, Vervloet MG, Hillebrands JL. Membrane-bound Klotho is not expressed endogenously in healthy or uraemic human vascular tissue. Cardiovasc Res 2015; 108:220-31. [PMID: 26116633 DOI: 10.1093/cvr/cvv187] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [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: 08/27/2014] [Accepted: 06/23/2015] [Indexed: 01/29/2023] Open
Abstract
AIMS Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD), a disease state that is strongly associated with loss of renal and systemic (alpha-)Klotho. Reversely, murine Klotho deficiency causes marked medial calcification. It is therefore thought that Klotho conveys a vasculoprotective effect. Klotho expression in the vessel wall, however, is disputed. METHODS AND RESULTS We assessed Klotho expression in healthy human renal donor arteries (n = 9), CKD (renal graft recipient) arteries (n = 10), carotid endarterectomy specimens (n = 8), other elastic arteries (three groups of n = 3), and cultured human aortic smooth muscle cells (HASMCs) (three primary cell lines), using immunohistochemistry (IHC), immunofluorescence, quantitative reverse transcriptase-polymerase chain reaction, and western blotting (WB). We have extensively validated anti-Klotho antibody KM2076 by comparing staining patterns with other anti-Klotho antibodies (SC-22220, SC-22218, and AF1819), competition assays with recombinant Klotho, IHC on Klotho-deficient kl/kl mouse kidney, and WB with recombinant Klotho. Using KM2076, we could not detect full-length Klotho in vascular tissues or HASMCs. On the mRNA level, using primers against all four exon junctions, klotho expression could not be detected either. Fibroblast growth factor 23 (FGF23) injections in mice induced FGF23 signalling in kidneys but not in the aorta, indicating the absence of Klotho-dependent FGF23 signalling in the aorta. CONCLUSION Using several independent and validated methods, we conclude that full-length, membrane-bound Klotho is not expressed in healthy or uraemic human vascular tissue.
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Affiliation(s)
- Rik Mencke
- Department of Pathology and Medical Biology (Division of Pathology), University of Groningen, University Medical Center Groningen, HPC EA10, PO Box 30.001, Groningen 9700 RB, The Netherlands
| | - Geert Harms
- Department of Pathology and Medical Biology (Division of Pathology), University of Groningen, University Medical Center Groningen, HPC EA10, PO Box 30.001, Groningen 9700 RB, The Netherlands
| | - Katarina Mirković
- Department of Internal Medicine (Division of Nephrology), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Joyce Struik
- Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Joris Van Ark
- Department of Pathology and Medical Biology (Division of Pathology), University of Groningen, University Medical Center Groningen, HPC EA10, PO Box 30.001, Groningen 9700 RB, The Netherlands
| | - Ellen Van Loon
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Melissa Verkaik
- Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Martin H De Borst
- Department of Internal Medicine (Division of Nephrology), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Clark J Zeebregts
- Department of Surgery (Division of Vascular Surgery), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marc G Vervloet
- Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Jan-Luuk Hillebrands
- Department of Pathology and Medical Biology (Division of Pathology), University of Groningen, University Medical Center Groningen, HPC EA10, PO Box 30.001, Groningen 9700 RB, The Netherlands
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18
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Jansen J, Schophuizen CMS, Wilmer MJ, Lahham SHM, Mutsaers HAM, Wetzels JFM, Bank RA, van den Heuvel LP, Hoenderop JG, Masereeuw R. A morphological and functional comparison of proximal tubule cell lines established from human urine and kidney tissue. Exp Cell Res 2014; 323:87-99. [PMID: 24560744 DOI: 10.1016/j.yexcr.2014.02.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [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: 10/14/2013] [Revised: 01/22/2014] [Accepted: 02/09/2014] [Indexed: 10/25/2022]
Abstract
Promising renal replacement therapies include the development of a bioartificial kidney using functional human kidney cell models. In this study, human conditionally immortalized proximal tubular epithelial cell (ciPTEC) lines originating from kidney tissue (ciPTEC-T1 and ciPTEC-T2) were compared to ciPTEC previously isolated from urine (ciPTEC-U). Subclones of all ciPTEC isolates formed tight cell layers on Transwell inserts as determined by transepithelial resistance, inulin diffusion, E-cadherin expression and immunocytochemisty. Extracellular matrix genes collagen I and -IV α1 were highly present in both kidney tissue derived matured cell lines (p<0.001) compared to matured ciPTEC-U, whereas matured ciPTEC-U showed a more pronounced fibronectin I and laminin 5 gene expression (p<0.01 and p<0.05, respectively). Expression of the influx carrier Organic Cation Transporter 2 (OCT-2), and the efflux pumps P-glycoprotein (P-gp), Multidrug Resistance Protein 4 (MRP4) and Breast Cancer Resistance Protein (BCRP) were confirmed in the three cell lines using real-time PCR and Western blotting. The activities of OCT-2 and P-gp were sensitive to specific inhibition in all models (p<0.001). The highest activity of MRP4 and BCRP was demonstrated in ciPTEC-U (p<0.05). Finally, active albumin reabsorption was highest in ciPTEC-T2 (p<0.001), while Na(+)-dependent phosphate reabsorption was most abundant in ciPTEC-U (p<0.01). In conclusion, ciPTEC established from human urine or kidney tissue display comparable functional PTEC specific transporters and physiological characteristics, providing ideal human tools for bioartificial kidney development.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP Binding Cassette Transporter, Subfamily G, Member 2
- ATP-Binding Cassette Transporters/biosynthesis
- ATP-Binding Cassette Transporters/metabolism
- Bioartificial Organs
- Cadherins/biosynthesis
- Cell Adhesion Molecules/biosynthesis
- Cell Culture Techniques
- Cell Line
- Collagen Type I/biosynthesis
- Collagen Type I/metabolism
- Fibronectins/biosynthesis
- Humans
- Inulin/metabolism
- Kidney Tubules, Proximal/cytology
- Kidneys, Artificial
- Multidrug Resistance-Associated Proteins/biosynthesis
- Multidrug Resistance-Associated Proteins/metabolism
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/metabolism
- Octamer Transcription Factor-2/antagonists & inhibitors
- Octamer Transcription Factor-2/biosynthesis
- Octamer Transcription Factor-2/metabolism
- Tissue Engineering
- Transendothelial and Transepithelial Migration/physiology
- Urine/cytology
- Kalinin
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Affiliation(s)
- J Jansen
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Pediatrics, Radboud University Medical Center, The Netherlands
| | - C M S Schophuizen
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Pediatrics, Radboud University Medical Center, The Netherlands
| | - M J Wilmer
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - S H M Lahham
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - H A M Mutsaers
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Pediatrics, Radboud University Medical Center, The Netherlands
| | - J F M Wetzels
- Department of Nephrology, Radboud University Medical Center, The Netherlands
| | - R A Bank
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - L P van den Heuvel
- Department of Pediatrics, Radboud University Medical Center, The Netherlands; Department of Pediatrics, Catholic University Leuven, Leuven, Belgium
| | - J G Hoenderop
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - R Masereeuw
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands.
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Lainez S, Schlingmann KP, van der Wijst J, Dworniczak B, van Zeeland F, Konrad M, Bindels RJ, Hoenderop JG. New TRPM6 missense mutations linked to hypomagnesemia with secondary hypocalcemia. Eur J Hum Genet 2013; 22:497-504. [PMID: 23942199 DOI: 10.1038/ejhg.2013.178] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 06/20/2013] [Accepted: 07/11/2013] [Indexed: 11/09/2022] Open
Abstract
Despite recent progress in our understanding of renal magnesium (Mg(2+)) handling, the molecular mechanisms accounting for transepithelial Mg(2+) transport are still poorly understood. Mutations in the TRPM6 gene, encoding the epithelial Mg(2+) channel TRPM6 (transient receptor potential melastatin 6), have been proven to be the molecular cause of hypomagnesemia with secondary hypocalcemia (HSH; OMIM 602014). HSH manifests in the newborn period being characterized by very low serum Mg(2+) levels (<0.4 mmol/l) accompanied by low serum calcium (Ca(2+)) concentrations. A proportion of previously described TRPM6 mutations lead to a truncated TRPM6 protein resulting in a complete loss-of-function of the ion channel. In addition, five-point mutations have been previously described. The aim of this study was to complement the current clinical picture by adding the molecular data from five new missense mutations found in five patients with HSH. To this end, patch-clamp analysis and cell surface measurements were performed to assess the effect of the various mutations on TRPM6 channel function. All mutant channels, expressed in HEK293 cells, showed loss-of-function, whereas no severe trafficking impairment to the plasma membrane surface was observed. We conclude that the new TRPM6 missense mutations lead to dysregulated intestinal/renal Mg(2+) (re)absorption as a consequence of loss of TRPM6 channel function.
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Affiliation(s)
- Sergio Lainez
- 1] Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands [2] Department of Pharmacology, University of Cambridge, Cambridge, UK
| | | | - Jenny van der Wijst
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Bernd Dworniczak
- Department of Human Genetics, Westfaelische Wilhelms Universität, Münster, Germany
| | - Femke van Zeeland
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Martin Konrad
- Department of General Pediatrics, University Hospital Münster, Münster, Germany
| | - René J Bindels
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
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20
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Mutsaers HAM, Engelke UFH, Wilmer MJG, Wetzels JFM, Wevers RA, van den Heuvel LP, Hoenderop JG, Masereeuw R. Optimized metabolomic approach to identify uremic solutes in plasma of stage 3-4 chronic kidney disease patients. PLoS One 2013; 8:e71199. [PMID: 23936492 PMCID: PMC3732267 DOI: 10.1371/journal.pone.0071199] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 06/28/2013] [Indexed: 11/18/2022] Open
Abstract
Background Chronic kidney disease (CKD) is characterized by the progressive accumulation of various potential toxic solutes. Furthermore, uremic plasma is a complex mixture hampering accurate determination of uremic toxin levels and the identification of novel uremic solutes. Methods In this study, we applied 1H-nuclear magnetic resonance (NMR) spectroscopy, following three distinct deproteinization strategies, to determine differences in the plasma metabolic status of stage 3–4 CKD patients and healthy controls. Moreover, the human renal proximal tubule cell line (ciPTEC) was used to study the influence of newly indentified uremic solutes on renal phenotype and functionality. Results Protein removal via ultrafiltration and acetonitrile precipitation are complementary techniques and both are required to obtain a clear metabolome profile. This new approach, revealed that a total of 14 metabolites were elevated in uremic plasma. In addition to confirming the retention of several previously identified uremic toxins, including p-cresyl sulphate, two novel uremic retentions solutes were detected, namely dimethyl sulphone (DMSO2) and 2-hydroxyisobutyric acid (2-HIBA). Our results show that these metabolites accumulate in non-dialysis CKD patients from 9±7 µM (control) to 51±29 µM and from 7 (0–9) µM (control) to 32±15 µM, respectively. Furthermore, exposure of ciPTEC to clinically relevant concentrations of both solutes resulted in an increased protein expression of the mesenchymal marker vimentin with more than 10% (p<0.05). Moreover, the loss of epithelial characteristics significantly correlated with a loss of glucuronidation activity (Pearson r = −0.63; p<0.05). In addition, both solutes did not affect cell viability nor mitochondrial activity. Conclusions This study demonstrates the importance of sample preparation techniques in the identification of uremic retention solutes using 1H-NMR spectroscopy, and provide insight into the negative impact of DMSO2 and 2-HIBA on ciPTEC, which could aid in understanding the progressive nature of renal disease.
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Affiliation(s)
- Henricus A. M. Mutsaers
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Udo F. H. Engelke
- Department of Laboratory Medicine, Laboratory of Genetic, Endocrine and Metabolic Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Martijn J. G. Wilmer
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Jack F. M. Wetzels
- Department of Nephrology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Ron A. Wevers
- Department of Laboratory Medicine, Laboratory of Genetic, Endocrine and Metabolic Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lambertus P. van den Heuvel
- Department of Laboratory Medicine, Laboratory of Genetic, Endocrine and Metabolic Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department of Pediatrics, Catholic University Leuven, Leuven, Belgium
| | - Joost G. Hoenderop
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Rosalinde Masereeuw
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
- * E-mail:
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21
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Lameris AL, Huybers S, Kaukinen K, Mäkelä TH, Bindels RJ, Hoenderop JG, Nevalainen PI. Expression profiling of claudins in the human gastrointestinal tract in health and during inflammatory bowel disease. Scand J Gastroenterol 2013. [PMID: 23205909 DOI: 10.3109/00365521.2012.741616] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Claudins, being part of the tight junction protein family, partially determine the integrity and paracellular permeability of the intestinal epithelium. The aim of this study was twofold. First, the authors set out to create an overview of claudin mRNA expression along the proximal-distal axis of the healthy human intestine. Second, the authors aimed to analyze expression levels of claudins in patients with active and inactive inflammatory bowel diseases (IBD) such as Crohn's disease or ulcerative colitis (UC). METHODS mRNA expression levels of claudins were determined in gastrointestinal biopsies from healthy patients as well as patients diagnosed with IBD using SybrGreen real-time PCR. RESULTS Claudins show distinct expression patterns throughout the gastrointestinal tract. Some claudins show a proximal expression pattern, such as CLDN18 which is solely expressed in the stomach, and CLDN2 and -15 that are predominantly expressed in the proximal parts of the gastrointestinal tract. Other claudins, such as CLDN3, -4, -7 and -8, are predominantly expressed in the distal parts of the gastrointestinal tract or show a ubiquitous expression pattern throughout the entire gastrointestinal tract, which is the case for CLDN12. In addition, we show that changes in claudin expression in IBD are dependent on gastrointestinal location and inflammatory activity. CONCLUSIONS This study provides detailed mRNA expression patterns of various claudins throughout the human gastrointestinal tract. Analysis of expression levels of claudins in patients with CD, active and inactive UC shows that changes in expression are confined to specific intestinal segments and strongly depend on inflammatory activity.
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Affiliation(s)
- Anke L Lameris
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre , The Netherlands
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22
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Lammers G, Poelkens F, van Duijnhoven NTL, Pardoel EM, Hoenderop JG, Thijssen DHJ, Hopman MTE. Expression of genes involved in fatty acid transport and insulin signaling is altered by physical inactivity and exercise training in human skeletal muscle. Am J Physiol Endocrinol Metab 2012; 303:E1245-51. [PMID: 23011062 DOI: 10.1152/ajpendo.00356.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [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: 01/17/2023]
Abstract
Physical deconditioning is associated with the development of chronic diseases, including type 2 diabetes and cardiovascular disease. Exercise training effectively counteracts these developments, but the underlying mechanisms are largely unknown. To gain more insight into these mechanisms, muscular gene expression levels were assessed after physical deconditioning and after exercise training of the lower limbs in humans by use of gene expression microarrays. To exclude systemic effects, we used human models for local physical inactivity (3 wk of unilateral limb suspension) and for local exercise training (6 wk of functional electrical stimulation exercise of the extremely deconditioned legs of individuals with a spinal cord injury). The most interesting subset of genes, those downregulated after deconditioning as well as upregulated after exercise training, contained 18 genes related to both the "insulin action" and "adipocytokine signaling" pathway. Of these genes, the three with strongest up/downregulation were the muscular fatty acid-binding protein-3 (FABP3), the fatty acid oxidizing enzyme hydroxyacyl-CoA dehydrogenase (HADH), and the mitochondrial fatty acid transporter solute carrier 25 family member A20 (SLC25A20). The expression levels of these genes were confirmed using RT-qPCR. The results of the present study indicate an important role for a decreased transport and metabolism of fatty acids, which provides a link between physical activity levels and insulin signaling.
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Affiliation(s)
- Gerwen Lammers
- Dept. of Physiology, Radboud Univ. Nijmegen Medical Centre, Nijmegen, The Netherlands
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23
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Lammers G, van Duijnhoven NTL, Hoenderop JG, Horstman AM, de Haan A, Janssen TWJ, de Graaf MJJ, Pardoel EM, Verwiel ETP, Thijssen DHJ, Hopman MTE. The identification of genetic pathways involved in vascular adaptations after physical deconditioningversusexercise training in humans. Exp Physiol 2012; 98:710-21. [DOI: 10.1113/expphysiol.2012.068726] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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van Angelen AA, van der Kemp AW, Hoenderop JG, Bindels RJ. Increased expression of renal TRPM6 compensates for Mg(2+) wasting during furosemide treatment. Clin Kidney J 2012; 5:535-44. [PMID: 26069797 PMCID: PMC4400563 DOI: 10.1093/ckj/sfs140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 09/06/2012] [Indexed: 11/23/2022] Open
Abstract
Background Furosemide is a loop diuretic, which blocks the Na+, K+, 2Cl− cotransporter (NKCC2) in the thick ascending limb of Henle (TAL). By diminishing sodium (Na+) reabsorption, loop diuretics reduce the lumen-positive transepithelial voltage and consequently diminish paracellular transport of magnesium (Mg2+) and calcium (Ca2+) in TAL. Indeed, furosemide promotes urinary Mg2+ excretion; however, it is unclear whether this leads, especially during prolonged treatment, to hypomagnesaemia. The aim of the present study was, therefore, to determine the effect of chronic furosemide application on renal Mg2+ handling in mice. Methods Two groups of 10 mice received an osmotic minipump subcutaneously for 7 days with vehicle or 30 mg/kg/day furosemide. Serum and urine electrolyte concentrations were determined. Next, renal mRNA levels of the epithelial Mg2+ channel (TRPM6), the Na+, Cl− cotransporter (NCC), the epithelial Ca2+ channel (TRPV5), the cytosolic Ca2+-binding protein calbindin-D28K, as well parvalbumin (PV), claudin-7 (CLDN7) and claudin-8 (CLDN8), the epithelial Na+ channel (ENaC) and the Na+–H+ exchanger 3 (NHE3) were determined by real-time quantitative polymerase chain reaction. Renal protein levels of NCC, TRPV5, calbindin-D28K and ENaC were also measured using semi-quantitative immunohistochemistry and immunoblotting. Results The mice chronically treated with 30 mg/kg/day furosemide displayed a significant polyuria (2.1 ± 0.3 and 1.3 ± 0.2 mL/24 h, furosemide versus control respectively, P < 0.05). Furosemide treatment resulted in increased serum concentrations of Na+ [158 ± 3 (treated) and 147 ± 1 mmol/L (control), P < 0.01], whereas serum K+, Ca2+ and Mg2+ values were not significantly altered in mice treated with furosemide. Urinary excretion of Na+, K+, Ca2+ and Mg2+ was not affected by chronic furosemide treatment. The present study shows specific renal upregulation of TRPM6, NCC, TRPV5 and calbindin-D28K. Conclusions During chronic furosemide treatment, enhanced active reabsorption of Mg2+ via the epithelial channel TRPM6 in DCT compensates for the reduced reabsorption of Mg2+ in TAL.
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Affiliation(s)
- Annelies A van Angelen
- Department of Physiology , Radboud University Nijmegen Medical Centre , Nijmegen , the Netherlands
| | - AnneMiete W van der Kemp
- Department of Physiology , Radboud University Nijmegen Medical Centre , Nijmegen , the Netherlands
| | - Joost G Hoenderop
- Department of Physiology , Radboud University Nijmegen Medical Centre , Nijmegen , the Netherlands
| | - René J Bindels
- Department of Physiology , Radboud University Nijmegen Medical Centre , Nijmegen , the Netherlands
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25
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Lammers G, Duijnhoven NTL, Hoenderop JG, Horstman AM, Haan A, Janssen TW, Graaf M, Pardoel EM, Verwiel ET, Thijssen DH, Hopman MT. The identification of gene clusters that correlate with vascular adaptations after physical deconditioning and exercise training in humans. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1134.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gerwen Lammers
- PhysiologyRadboud University Nijmegen Medical CentreNijmegenNetherlands
| | | | | | - Astrid M.H. Horstman
- Research Institute MOVEFaculty of Human Movement SciencesVU University AmsterdamAmsterdamNetherlands
| | - Arnold Haan
- Research Institute MOVEFaculty of Human Movement SciencesVU University AmsterdamAmsterdamNetherlands
| | - Thomas W.J. Janssen
- Research Institute MOVEFaculty of Human Movement SciencesVU University AmsterdamAmsterdamNetherlands
- Amsterdam Rehabilitation Research Center ReadeAmsterdamNetherlands
| | - Mark Graaf
- PhysiologyRadboud University Nijmegen Medical CentreNijmegenNetherlands
| | | | | | - Dick H.J. Thijssen
- PhysiologyRadboud University Nijmegen Medical CentreNijmegenNetherlands
- Research Institute for Sports and Exercise ScienceLiverpool John Moores UniversityLiverpoolUnited Kingdom
| | - Maria T.E. Hopman
- PhysiologyRadboud University Nijmegen Medical CentreNijmegenNetherlands
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26
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Mutsaers HAM, Wilmer MJG, van den Heuvel LP, Hoenderop JG, Masereeuw R. Basolateral transport of the uraemic toxin p-cresyl sulfate: role for organic anion transporters? Nephrol Dial Transplant 2011; 26:4149. [PMID: 22025116 DOI: 10.1093/ndt/gfr562] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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27
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Boros S, Xi Q, Dimke H, van der Kemp AW, Tudpor K, Verkaart S, Lee KP, Bindels RJ, Hoenderop JG. Tissue transglutaminase inhibits the TRPV5-dependent calcium transport in an N-glycosylation-dependent manner. Cell Mol Life Sci 2011; 69:981-92. [PMID: 21952826 DOI: 10.1007/s00018-011-0818-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 08/25/2011] [Accepted: 09/06/2011] [Indexed: 01/28/2023]
Abstract
Tissue transglutaminase (tTG) is a multifunctional Ca(2+)-dependent enzyme, catalyzing protein crosslinking. The transient receptor potential vanilloid (TRPV) family of cation channels was recently shown to contribute to the regulation of TG activities in keratinocytes and hence skin barrier formation. In kidney, where active transcellular Ca(2+) transport via TRPV5 predominates, the potential effect of tTG remains unknown. A multitude of factors regulate TRPV5, many secreted into the pro-urine and acting from the extracellular side. We detected tTG in mouse urine and in the apical medium of polarized cultures of rabbit connecting tubule and cortical collecting duct (CNT/CCD) cells. Extracellular application of tTG significantly reduced TRPV5 activity in human embryonic kidney cells transiently expressing the channel. Similarly, a strong inhibition of transepithelial Ca(2+) transport was observed after apical application of purified tTG to polarized rabbit CNT/CCD cells. Furthermore, tTG promoted the aggregation of the plasma membrane-associated fraction of TRPV5. Using patch clamp analysis, we observed a reduction in the pore diameter after tTG treatment, suggesting distinct structural changes in TRPV5 upon crosslinking by tTG. As N-linked glycosylation of TRPV5 is a key step in regulating channel function, we determined the effect of tTG in the N-glycosylation-deficient TRPV5 mutant. In the absence of N-linked glycosylation, TRPV5 was insensitive to tTG. Taken together, these observations imply that tTG is a novel extracellular enzyme inhibiting the activity of TRPV5. The inhibition of TRPV5 occurs in an N-glycosylation-dependent manner, signifying a common final pathway by which distinct extracellular factors regulate channel activity.
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Affiliation(s)
- Sandor Boros
- 286 Department of Physiology, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
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28
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Pan W, Borovac J, Spicer Z, Hoenderop JG, Bindels RJ, Shull GE, Doschak MR, Cordat E, Alexander RT. The epithelial sodium/proton exchanger, NHE3, is necessary for renal and intestinal calcium (re)absorption. Am J Physiol Renal Physiol 2011; 302:F943-56. [PMID: 21937605 DOI: 10.1152/ajprenal.00504.2010] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Passive paracellular proximal tubular (PT) and intestinal calcium (Ca(2+)) fluxes have been linked to active sodium (re)absorption. Although the epithelial sodium/proton exchanger, NHE3, mediates apical sodium entry at both these sites, its role in Ca(2+) homeostasis remains unclear. We, therefore, set out to determine whether NHE3 is necessary for Ca(2+) (re)absorption from these epithelia by comparing Ca(2+) handling between wild-type and NHE3(-/-) mice. Serum Ca(2+) and plasma parathyroid hormone levels were not different between groups. However, NHE3(-/-) mice had increased serum 1,25-dihydroxyvitamin D(3). The fractional excretion of Ca(2+) was also elevated in NHE3(-/-) mice. Paracellular Ca(2+) flux across confluent monolayers of a PT cell culture model was increased by an osmotic gradient equivalent to that generated by NHE3 across the PT in vivo and by overexpression of NHE3.( 45)Ca(2+) uptake after oral gavage and flux studies in Ussing chambers across duodenum of wild-type and NHE3(-/-) mice confirmed decreased Ca(2+) absorption in NHE3(-/-) mice compared with wild-type mice. Consistent with this, intestinal calbindin-D(9K), claudin-2, and claudin-15 mRNA expression was decreased. Microcomputed tomography analysis revealed a perturbation in bone mineralization. NHE3(-/-) mice had both decreased cortical bone mineral density and trabecular bone mass. Our results demonstrate significant alterations of Ca(2+) homeostasis in NHE3(-/-) mice and provide a molecular link between Na(+) and Ca(2+) (re)absorption.
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Affiliation(s)
- Wanling Pan
- Division of Nephrology, Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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Janssen DA, Hoenderop JG, Jansen KC, Kemp AW, Heesakkers JP, Schalken JA. The Mechanoreceptor TRPV4 is Localized in Adherence Junctions of the Human Bladder Urothelium: A Morphological Study. J Urol 2011; 186:1121-7. [DOI: 10.1016/j.juro.2011.04.107] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Indexed: 01/30/2023]
Affiliation(s)
- Dick A.W. Janssen
- Departments of Urology and Physiology (JGH, AWK), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joost G. Hoenderop
- Departments of Urology and Physiology (JGH, AWK), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Kees C.F.J. Jansen
- Departments of Urology and Physiology (JGH, AWK), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Annemiete W. Kemp
- Departments of Urology and Physiology (JGH, AWK), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - John P.F.A. Heesakkers
- Departments of Urology and Physiology (JGH, AWK), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jack A. Schalken
- Departments of Urology and Physiology (JGH, AWK), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Schlingmann KP, Kaufmann M, Weber S, Irwin A, Goos C, John U, Misselwitz J, Klaus G, Kuwertz-Bröking E, Fehrenbach H, Wingen AM, Güran T, Hoenderop JG, Bindels RJ, Prosser DE, Jones G, Konrad M. Mutations in CYP24A1 and idiopathic infantile hypercalcemia. N Engl J Med 2011; 365:410-21. [PMID: 21675912 DOI: 10.1056/nejmoa1103864] [Citation(s) in RCA: 370] [Impact Index Per Article: 28.5] [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: 01/06/2023]
Abstract
BACKGROUND Vitamin D supplementation for the prevention of rickets is one of the oldest and most effective prophylactic measures in medicine, having virtually eradicated rickets in North America. Given the potentially toxic effects of vitamin D, the recommendations for the optimal dose are still debated, in part owing to the increased incidence of idiopathic infantile hypercalcemia in Britain in the 1950s during a period of high vitamin D supplementation in fortified milk products. We investigated the molecular basis of idiopathic infantile hypercalcemia, which is characterized by severe hypercalcemia, failure to thrive, vomiting, dehydration, and nephrocalcinosis. METHODS We used a candidate-gene approach in a cohort of familial cases of typical idiopathic infantile hypercalcemia with suspected autosomal recessive inheritance. Identified mutations in the vitamin D-metabolizing enzyme CYP24A1 were evaluated with the use of a mammalian expression system. RESULTS Sequence analysis of CYP24A1, which encodes 25-hydroxyvitamin D 24-hydroxylase, the key enzyme of 1,25-dihydroxyvitamin D(3) degradation, revealed recessive mutations in six affected children. In addition, CYP24A1 mutations were identified in a second cohort of infants in whom severe hypercalcemia had developed after bolus prophylaxis with vitamin D. Functional characterization revealed a complete loss of function in all CYP24A1 mutations. CONCLUSIONS The presence of CYP24A1 mutations explains the increased sensitivity to vitamin D in patients with idiopathic infantile hypercalcemia and is a genetic risk factor for the development of symptomatic hypercalcemia that may be triggered by vitamin D prophylaxis in otherwise apparently healthy infants.
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Mutsaers HAM, van den Heuvel LP, Ringens LHJ, Dankers ACA, Russel FGM, Wetzels JFM, Hoenderop JG, Masereeuw R. Uremic toxins inhibit transport by breast cancer resistance protein and multidrug resistance protein 4 at clinically relevant concentrations. PLoS One 2011; 6:e18438. [PMID: 21483698 PMCID: PMC3070735 DOI: 10.1371/journal.pone.0018438] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 03/07/2011] [Indexed: 11/18/2022] Open
Abstract
During chronic kidney disease (CKD), there is a progressive accumulation of toxic solutes due to inadequate renal clearance. Here, the interaction between uremic toxins and two important efflux pumps, viz. multidrug resistance protein 4 (MRP4) and breast cancer resistance protein (BCRP) was investigated. Membrane vesicles isolated from MRP4- or BCRP-overexpressing human embryonic kidney cells were used to study the impact of uremic toxins on substrate specific uptake. Furthermore, the concentrations of various uremic toxins were determined in plasma of CKD patients using high performance liquid chromatography and liquid chromatography/tandem mass spectrometry. Our results show that hippuric acid, indoxyl sulfate and kynurenic acid inhibit MRP4-mediated [3H]-methotrexate ([3H]-MTX) uptake (calculated Ki values: 2.5 mM, 1 mM, 25 µM, respectively) and BCRP-mediated [3H]-estrone sulfate ([3H]-E1S) uptake (Ki values: 4 mM, 500 µM and 50 µM, respectively), whereas indole-3-acetic acid and phenylacetic acid reduce [3H]-MTX uptake by MRP4 only (Ki value: 2 mM and IC50 value: 7 mM, respectively). In contrast, p-cresol, p-toluenesulfonic acid, putrescine, oxalate and quinolinic acid did not alter transport mediated by MRP4 or BCRP. In addition, our results show that hippuric acid, indole-3-acetic acid, indoxyl sulfate, kynurenic acid and phenylacetic acid accumulate in plasma of end-stage CKD patients with mean concentrations of 160 µM, 4 µM, 129 µM, 1 µM and 18 µM, respectively. Moreover, calculated Ki values are below the maximal plasma concentrations of the tested toxins. In conclusion, this study shows that several uremic toxins inhibit active transport by MRP4 and BCRP at clinically relevant concentrations.
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Affiliation(s)
- Henricus A. M. Mutsaers
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Lambertus P. van den Heuvel
- Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department of Pediatrics, Catholic University Leuven, Leuven, Belgium
| | - Lauke H. J. Ringens
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Anita C. A. Dankers
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Frans G. M. Russel
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Jack F. M. Wetzels
- Department of Nephrology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joost G. Hoenderop
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Rosalinde Masereeuw
- Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
- * E-mail:
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Markadieu N, Bindels RJ, Hoenderop JG. The renal connecting tubule: Resolved and unresolved issues in Ca(2+) transport. Int J Biochem Cell Biol 2010; 43:1-4. [PMID: 20969972 DOI: 10.1016/j.biocel.2010.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/07/2010] [Accepted: 10/14/2010] [Indexed: 10/18/2022]
Abstract
The renal connecting tubule (CNT) localizes to the distal part of the nephron between the distal convoluted tubule and the collecting duct, and consists of two different cell types: segment-specific and intercalated cells. The former reabsorb water (H(2)O), sodium (Na(+)) and calcium (Ca(2+)) ions to the blood compartment, while secreting potassium ions (K(+)) into the pro-urine. The latter cells contribute to the renal control of the acid-base balance. Several factors and hormones tightly regulate these transport processes. Although the CNT reabsorbs only ∼15% of filtered Ca(2+) load, this segment is finally decisive for the amount of Ca(2+) that appears in the urine. Impaired Ca(2+) transport across CNT can provoke severe urinary Ca(2+) excretion, called hypercalciuria. This review mainly focuses on the activity, abundance and expression of the epithelial Ca(2+) channel named Transient Receptor Potential Vanilloid 5 (TRPV5) that is the gatekeeper of active Ca(2+) reabsorption in the CNT.
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Affiliation(s)
- Nicolas Markadieu
- Department of Physiology, Radboud University Nijmegen Medical Centre, The Netherlands
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Dimke H, van der Wijst J, Alexander TR, Meijer IMJ, Mulder GM, van Goor H, Tejpar S, Hoenderop JG, Bindels RJ. Effects of the EGFR Inhibitor Erlotinib on Magnesium Handling. J Am Soc Nephrol 2010; 21:1309-16. [PMID: 20595681 DOI: 10.1681/asn.2009111153] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A mutation in pro-EGF causes isolated hypomagnesemia, and monoclonal antibodies targeting the extracellular domain of the EGF receptor (EGFR) affect epithelial Mg(2+) transport. The effect of the EGFR tyrosine kinase inhibitor erlotinib on Mg(2+) homeostasis, however, remains unknown. Here, we injected C57BL/6 mice with erlotinib for 23 days and observed a small but significant decrease in serum Mg(2+) concentrations at days 16 and 23, but the fractional excretion of Mg(2+) remained unchanged after 23 days. Semiquantitative immunohistochemical evaluation did not reveal detectable changes in renal expression of transient receptor potential melastatin 6 (TRPM6) protein, the channel that mediates Mg(2+) reabsorption. Patch clamp analysis in TRPM6-expressing cells demonstrated that 30 muM erlotinib inhibited EGF-induced changes in TRPM6 current density and tyrosine phosphorylation of EGFR; 0.3 muM erlotinib did not have these effects. Furthermore, 30 muM erlotinib inhibited EGF-stimulated increases in the mobile fraction of endomembrane TRPM6 channels. In summary, erlotinib can influence Mg(2+) handling but its effect on the systemic Mg(2+) concentration seems less potent than that observed with antibody-based EGFR inhibitors. These data suggest that typical human dosages of erlotinib are unlikely to severely affect serum Mg(2+) concentrations.
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Affiliation(s)
- Henrik Dimke
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Glaudemans B, van der Wijst J, Scola R, Lorenzoni PJ, Heister A, van der Kemp A, Knoers NV, Hoenderop JG, Bindels RJ. Rare but Relevant Kidney Disorders. Clin J Am Soc Nephrol 2009. [DOI: 10.2215/01.cjn.0000927056.12668.a8] [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: 03/28/2023]
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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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Alexander RT, Woudenberg-Vrenken TE, Buurman J, Dijkman H, van der Eerden BCJ, van Leeuwen JPTM, Bindels RJ, Hoenderop JG. Klotho prevents renal calcium loss. J Am Soc Nephrol 2009; 20:2371-9. [PMID: 19713312 DOI: 10.1681/asn.2008121273] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Disturbed calcium (Ca(2+)) homeostasis, which is implicit to the aging phenotype of klotho-deficient mice, has been attributed to altered vitamin D metabolism, but alternative possibilities exist. We hypothesized that failed tubular Ca(2+) absorption is primary, which causes increased urinary Ca(2+) excretion, leading to elevated 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] and its sequelae. Here, we assessed intestinal Ca(2+) absorption, bone densitometry, renal Ca(2+) excretion, and renal morphology via energy-dispersive x-ray microanalysis in wild-type and klotho(-/-) mice. We observed elevated serum Ca(2+) and fractional excretion of Ca(2+) (FE(Ca)) in klotho(-/-) mice. Klotho(-/-) mice also showed intestinal Ca(2+) hyperabsorption, osteopenia, and renal precipitation of calcium-phosphate. Duodenal mRNA levels of transient receptor potential vanilloid 6 (TRPV6) and calbindin-D(9K) increased. In the kidney, klotho(-/-) mice exhibited increased expression of TRPV5 and decreased expression of the sodium/calcium exchanger (NCX1) and calbindin-D(28K), implying a failure to absorb Ca(2+) through the distal convoluted tubule/connecting tubule (DCT/CNT) via TRPV5. Gene and protein expression of the vitamin D receptor (VDR), 25-hydroxyvitamin D-1-alpha-hydroxylase (1alphaOHase), and calbindin-D(9K) excluded renal vitamin D resistance. By modulating the diet, we showed that the renal Ca(2+) wasting was not secondary to hypercalcemia and/or hypervitaminosis D. In summary, these findings illustrate a primary defect in tubular Ca(2+) handling that contributes to the precipitation of calcium-phosphate in DCT/CNT. This highlights the importance of klotho to the prevention of renal Ca(2+) loss, secondary hypervitaminosis D, osteopenia, and nephrocalcinosis.
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Affiliation(s)
- R Todd Alexander
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, , 6500 HB Nijmegen, The Netherlands
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Renkema KY, Velic A, Dijkman HB, Verkaart S, van der Kemp AW, Nowik M, Timmermans K, Doucet A, Wagner CA, Bindels RJ, Hoenderop JG. The calcium-sensing receptor promotes urinary acidification to prevent nephrolithiasis. J Am Soc Nephrol 2009; 20:1705-13. [PMID: 19470676 DOI: 10.1681/asn.2008111195] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Hypercalciuria increases the risk for urolithiasis, but renal adaptive mechanisms reduce this risk. For example, transient receptor potential vanilloid 5 knockout (TPRV5(-/-)) mice lack kidney stones despite urinary calcium (Ca(2+)) wasting and hyperphosphaturia, perhaps as a result of their significant polyuria and urinary acidification. Here, we investigated the mechanisms linking hypercalciuria with these adaptive mechanisms. Exposure of dissected mouse outer medullary collecting ducts to high (5.0 mM) extracellular Ca(2+) stimulated H(+)-ATPase activity. In TRPV5(-/-) mice, activation of the renal Ca(2+)-sensing receptor promoted H(+)-ATPase-mediated H(+) excretion and downregulation of aquaporin 2, leading to urinary acidification and polyuria, respectively. Gene ablation of the collecting duct-specific B1 subunit of H(+)-ATPase in TRPV5(-/-) mice abolished the enhanced urinary acidification, which resulted in severe tubular precipitations of Ca(2+)-phosphate in the renal medulla. In conclusion, activation of Ca(2+)-sensing receptor by increased luminal Ca(2+) leads to urinary acidification and polyuria. These beneficial adaptations facilitate the excretion of large amounts of soluble Ca(2+), which is crucial to prevent the formation of kidney stones.
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Affiliation(s)
- Kirsten Y Renkema
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
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Cao G, van der Wijst J, van der Kemp A, van Zeeland F, Bindels RJ, Hoenderop JG. Regulation of the epithelial Mg2+ channel TRPM6 by estrogen and the associated repressor protein of estrogen receptor activity (REA). J Biol Chem 2009; 284:14788-95. [PMID: 19329436 DOI: 10.1074/jbc.m808752200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The maintenance of the Mg(2+) balance of the body is essential for neuromuscular excitability, protein synthesis, nucleic acid stability, and numerous enzymatic systems. The Transient Receptor Potential Melastatin 6 (TRPM6) functions as the gatekeeper of transepithelial Mg(2+) transport. However, the molecular regulation of TRPM6 channel activity remains elusive. Here, we identified the repressor of estrogen receptor activity (REA) as an interacting protein of TRPM6 that binds to the 6(th), 7(th), and 8(th) beta-sheets in its alpha-kinase domain. Importantly, REA and TRPM6 are coexpressed in renal Mg(2+)-transporting distal convoluted tubules (DCT). We demonstrated that REA significantly inhibits TRPM6, but not its closest homologue TRPM7, channel activity. This inhibition occurs in a phosphorylation-dependent manner, since REA has no effect on the TRPM6 phosphotransferase-deficient mutant (K1804R), while it still binds to this mutant. Moreover, activation of protein kinase C by phorbol 12-myristate 13-acetate-PMA potentiated the inhibitory effect of REA on TRPM6 channel activity. Finally, we showed that the interaction between REA and TRPM6 is a dynamic process, as short-term 17beta-estradiol treatment disassociates the binding between these proteins. In agreement with this, 17beta-estradiol treatment significantly stimulates the TRPM6-mediated current in HEK293 cells. These results suggest a rapid pathway for the effect of estrogen on Mg(2+) homeostasis in addition to its transcriptional effect. Together, these data indicate that REA operates as a negative feedback modulator of TRPM6 in the regulation of active Mg(2+) (re)absorption and provides new insight into the molecular mechanism of renal transepithelial Mg(2+) transport.
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Affiliation(s)
- Gang Cao
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Institute for Genetic and Metabolic Disease, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
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Glaudemans B, van der Wijst J, Scola RH, Lorenzoni PJ, Heister A, van der Kemp AW, Knoers NV, Hoenderop JG, Bindels RJ. A missense mutation in the Kv1.1 voltage-gated potassium channel-encoding gene KCNA1 is linked to human autosomal dominant hypomagnesemia. J Clin Invest 2009; 119:936-42. [PMID: 19307729 DOI: 10.1172/jci36948] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 01/07/2009] [Indexed: 02/04/2023] Open
Abstract
Primary hypomagnesemia is a heterogeneous group of disorders characterized by renal or intestinal magnesium (Mg2+) wasting, resulting in tetany, cardiac arrhythmias, and seizures. The kidney plays an essential role in maintaining blood Mg2+ levels, with a prominent function for the Mg2+-transporting channel transient receptor potential cation channel, subfamily M, member 6 (TRPM6) in the distal convoluted tubule (DCT). In the DCT, Mg2+ reabsorption is an active transport process primarily driven by the negative potential across the luminal membrane. Here, we studied a family with isolated autosomal dominant hypomagnesemia and used a positional cloning approach to identify an N255D mutation in KCNA1, a gene encoding the voltage-gated potassium (K+) channel Kv1.1. Kv1.1 was found to be expressed in the kidney, where it colocalized with TRPM6 along the luminal membrane of the DCT. Upon overexpression in a human kidney cell line, patch clamp analysis revealed that the KCNA1 N255D mutation resulted in a nonfunctional channel, with a dominant negative effect on wild-type Kv1.1 channel function. These data suggest that Kv1.1 is a renal K+ channel that establishes a favorable luminal membrane potential in DCT cells to control TRPM6-mediated Mg2+ reabsorption.
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Affiliation(s)
- Bob Glaudemans
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Renkema KY, Lee K, Topala CN, Goossens M, Houillier P, Bindels RJ, Hoenderop JG. TRPV5 gene polymorphisms in renal hypercalciuria. Nephrol Dial Transplant 2009; 24:1919-24. [PMID: 19131347 DOI: 10.1093/ndt/gfn735] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Kidney stone formation is a major socioeconomic problem in humans, involving pain, recurrent treatment and renal insufficiency. As most renal precipitates contain calcium as a major component, hypercalciuria is the main risk factor for renal stone formation. Different forms of hypercalciuria can be classified, which primarily arise from defects in the main organs involved in calcium homeostasis. A distinction can be made between renal, absorptive and resorptive hypercalciuria, originating from disturbed calcium handling in kidney, intestine and bone, respectively. A positive family history predisposes individuals to an increased risk of stone formation, which strongly indicates the involvement of genetic susceptibility factors. TRPV5 is the renal epithelial calcium channel that is the gatekeeper protein in active calcium reabsorption in the kidney. TRPV5 gene ablation in mice leads to severe hypercalciuria, implying that TRPV5 is an interesting candidate gene for renal hypercalciuria in humans. This study aims to identify and functionally characterize TRPV5 gene aberrations in patients with renal hypercalciuria. METHODS The TRPV5 coding region and intron-exon boundaries were screened for gene mutations in 20 subjects displaying renal hypercalciuria after which identified non-synonymous polymorphisms were functionally characterized by patch-clamp analysis. Wild-type and TRPV5 channels including polymorphisms were transiently expressed in human embryonic kidney (HEK) 293 cells and functionally characterized by path-clamp analysis. RESULTS Genotyping TRPV5 in renal hypercalciuria patients revealed three non-synonymous and five synonymous polymorphisms. Electrophysiological characterization of the TRPV5 mutants did not reveal significant functional changes compared to wild-type TRPV5 channel recordings. CONCLUSIONS In this specific patient cohort, our data do not support a primary role for TRPV5 in the pathogenesis of renal hypercalciuria. However, TRPV5 cannot be excluded as a candidate gene in hypercalciuria.
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Affiliation(s)
- Kirsten Y Renkema
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, The Netherlands
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Abstract
Recent identification of a mutation in the EGF gene that causes isolated recessive hypomagnesemia led to the finding that EGF increases the activity of the epithelial magnesium (Mg2+) channel transient receptor potential M6 (TRPM6). To investigate the molecular mechanism mediating this effect, we performed whole-cell patch-clamp recordings of TRPM6 expressed in human embryonic kidney 293 (HEK293) cells. Stimulation of the EGF receptor increased current through TRPM6 but not TRPM7. The carboxy-terminal alpha-kinase domain of TRPM6 did not participate in the EGF receptor-mediated increase in channel activity. This activation relied on both the Src family of tyrosine kinases and the downstream effector Rac1. Activation of Rac1 increased the mobility of TRPM6, assessed by fluorescence recovery after photobleaching, and a constitutively active mutant of Rac1 mimicked the stimulatory effect of EGF on TRPM6 mobility and activity. Ultimately, TRPM6 activation resulted from increased cell surface abundance. In contrast, dominant negative Rac1 decreased TRPM6 mobility, abrogated current development, and prevented the EGF-mediated increase in channel activity. In summary, EGF-mediated stimulation of TRPM6 occurs via signaling through Src kinases and Rac1, thereby redistributing endomembrane TRPM6 to the plasma membrane. These results describe a regulatory mechanism for transepithelial Mg2+ transport and consequently whole-body Mg2+ homeostasis.
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Affiliation(s)
- Stéphanie Thebault
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
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Alexander RT, Hoenderop JG, Bindels RJ. Molecular determinants of magnesium homeostasis: insights from human disease. J Am Soc Nephrol 2008; 19:1451-8. [PMID: 18562569 DOI: 10.1681/asn.2008010098] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The past decade has witnessed multiple advances in our understanding of magnesium (Mg(2+)) homeostasis. The discovery that mutations in claudin-16/paracellin-1 or claudin-19 are responsible for familial hypomagnesemia with hypercalciuria and nephrocalcinosis provided insight into the molecular mechanisms governing paracellular transport of Mg(2+). Our understanding of the transcellular movement of Mg(2+) was similarly enhanced by the realization that defects in transient receptor potential melastatin 6 (TRPM6) cause hypomagnesemia with secondary hypocalcemia. This channel regulates the apical entry of Mg(2+) into epithelia. In so doing, TRPM6 alters whole-body Mg(2+) homeostasis by controlling urinary excretion. Consequently, investigation into the regulation of TRPM6 has increased. Acid-base status, 17beta estradiol, and the immunosuppressive agents FK506 and cyclosporine affect plasma Mg(2+) levels by altering TRPM6 expression. A mutation in epithelial growth factor is responsible for isolated autosomal recessive hypomagnesemia, and epithelial growth factor activates TRPM6. A defect in the gamma-subunit of the Na,K-ATPase causes isolated dominant hypomagnesemia by altering TRPM6 activity through a decrease in the driving force for apical Mg(2+) influx. We anticipate that the next decade will provide further detail into the control of the gatekeeper TRPM6 and, therefore, overall whole-body Mg(2+) balance.
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Affiliation(s)
- R Todd Alexander
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
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Abstract
Calcium (Ca(2+)) and phosphate (P(i)) are essential to many vital physiological processes. Consequently the maintenance of Ca(2+) and P(i) homeostasis is essential to a healthy existence. This occurs through the concerted action of intestinal, renal, and skeletal regulatory mechanisms. Ca(2+) and P(i) handling by these organs is under tight hormonal control. Disturbances in their homeostasis have been linked to pathophysiological disorders including chronic renal insufficiency, kidney stone formation, and bone abnormalities. Importantly, the kidneys fine-tune the amount of Ca(2+) and P(i) retained in the body by altering their (re)absorption from the glomerular filtrate. The ion transport proteins involved in this process have been studied extensively. Recently, new key players have been identified in the regulation of the Ca(2+) and P(i) balance. Novel regulatory mechanisms and their implications were introduced for the antiaging hormone klotho and fibroblast growth factor member 23 (FGF23). Importantly, transgenic mouse models, exhibiting disturbances in Ca(2+) and P(i) balance, have been of great value in the elucidation of klotho and FGF23 functioning. This review highlights the current knowledge and ongoing research into Ca(2+) and P(i) homeostasis, emphasizing findings from several relevant knockout mouse models.
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Affiliation(s)
- Kirsten Y Renkema
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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44
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Groenestege WMT, Thébault S, van der Wijst J, van den Berg D, Janssen R, Tejpar S, van den Heuvel LP, van Cutsem E, Hoenderop JG, Knoers NV, Bindels RJ. Impaired basolateral sorting of pro-EGF causes isolated recessive renal hypomagnesemia. J Clin Invest 2007; 117:2260-7. [PMID: 17671655 PMCID: PMC1934557 DOI: 10.1172/jci31680] [Citation(s) in RCA: 274] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 05/08/2007] [Indexed: 12/11/2022] Open
Abstract
Primary hypomagnesemia constitutes a rare heterogeneous group of disorders characterized by renal or intestinal magnesium (Mg(2+)) wasting resulting in generally shared symptoms of Mg(2+) depletion, such as tetany and generalized convulsions, and often including associated disturbances in calcium excretion. However, most of the genes involved in the physiology of Mg(2+) handling are unknown. Through the discovery of a mutation in the EGF gene in isolated autosomal recessive renal hypomagnesemia, we have, for what we believe is the first time, identified a magnesiotropic hormone crucial for total body Mg(2+) balance. The mutation leads to impaired basolateral sorting of pro-EGF. As a consequence, the renal EGFR is inadequately stimulated, resulting in insufficient activation of the epithelial Mg(2+) channel TRPM6 (transient receptor potential cation channel, subfamily M, member 6) and thereby Mg(2+) loss. Furthermore, we show that colorectal cancer patients treated with cetuximab, an antagonist of the EGFR, develop hypomagnesemia, emphasizing the significance of EGF in maintaining Mg(2+) balance.
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Affiliation(s)
- Wouter M. Tiel Groenestege
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Stéphanie Thébault
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Dennis van den Berg
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rob Janssen
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Sabine Tejpar
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lambertus P. van den Heuvel
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Eric van Cutsem
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joost G. Hoenderop
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Nine V. Knoers
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - René J. Bindels
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Belge H, Gailly P, Schwaller B, Loffing J, Debaix H, Riveira-Munoz E, Beauwens R, Devogelaer JP, Hoenderop JG, Bindels RJ, Devuyst O. Renal expression of parvalbumin is critical for NaCl handling and response to diuretics. Proc Natl Acad Sci U S A 2007; 104:14849-54. [PMID: 17804801 PMCID: PMC1976223 DOI: 10.1073/pnas.0702810104] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The distal convoluted tubule (DCT) plays an essential role in the reabsorption of NaCl by the kidney, a process that can be inhibited by thiazide diuretics. Parvalbumin (PV), a Ca(2+)-binding protein that plays a role in muscle fibers and neurons, is selectively expressed in the DCT, where its role remains unknown. We therefore investigated the renal phenotype of PV knockout mice (Pvalb(-/-)) vs. wild-type (Pvalb(+/+)) littermates. PV colocalized with the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) in the early DCT. The Pvalb(-/-) mice showed increased diuresis and kaliuresis at baseline with higher aldosterone levels and lower lithium clearance. Acute furosemide administration increased diuresis and natriuresis/kaliuresis, but, surprisingly, did not increase calciuria in Pvalb(-/-) mice. NaCl supplementation of Pvalb(-/-) mice increased calciuria at baseline and after furosemide. The Pvalb(-/-) mice showed no significant diuretic response to hydrochlorothiazide, but an accentuated hypocalciuria. A decreased expression of NCC was detected in the early DCT of Pvalb(-/-) kidneys in the absence of ultrastructural and apoptotic changes. The PV-deficient mice had a positive Ca(2+) balance and increased bone mineral density. Studies in mouse DCT cells showed that endogenous NCC expression is Ca(2+)-dependent and can be modulated by the levels of PV expression. These results suggest that PV regulates the expression of NCC by modulating intracellular Ca(2+) signaling in response to ATP in DCT cells. They also provide insights into the Ca(2+)-sparing action of thiazides and the pathophysiology of distal tubulopathies.
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Affiliation(s)
| | | | - Beat Schwaller
- Unit of Anatomy, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Johannes Loffing
- Unit of Anatomy, University of Fribourg, CH-1700 Fribourg, Switzerland
| | | | | | - Renaud Beauwens
- Laboratory of Cell and Molecular Physiology, Université Libre de Bruxelles Medical School, B-1070 Brussels, Belgium; and
| | | | - Joost G. Hoenderop
- Department of Physiology, Radboud University Nijmegen, 6500 HC Nijmegen, The Netherlands
| | - René J. Bindels
- Department of Physiology, Radboud University Nijmegen, 6500 HC Nijmegen, The Netherlands
| | - Olivier Devuyst
- Departments of *Nephrology
- **To whom correspondence should be addressed. E-mail:
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46
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Topala CN, Groenestege WT, Thébault S, van den Berg D, Nilius B, Hoenderop JG, Bindels RJ. Molecular determinants of permeation through the cation channel TRPM6. Cell Calcium 2007; 41:513-23. [PMID: 17098283 DOI: 10.1016/j.ceca.2006.10.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 09/04/2006] [Accepted: 10/03/2006] [Indexed: 11/15/2022]
Abstract
TRPM6 and its closest relative TRPM7 are members of the Transient Receptor Potential Melastatin (TRPM) subfamily of cation channels and are known to be Mg2+ permeable. By aligning the sequence of the putative TRPM6 pore with the pore sequences of the other subfamily members, we located in the loop between the fifth and the sixth transmembrane domain, a stretch of amino acids residues, 1028GEIDVC1033, as the potential selectivity filter. Two negatively charged residues, E1024 (conserved in TRPM6, TRPM7, TRPM1 and TRPM3) and D1031 (conserved along the entire TRPM subfamily), were identified as important determinants of cation permeation through TRPM6, because neutralization of both residues into an alanine resulted in non-functional channels. Neutralization of E1029 (conserved in TRPM6, TRPM7, TRPM4 and TRPM5) resulted in channels with increased conductance for Ba2+ and Zn2+, decreased ruthenium red sensitivity and larger pore diameter compared to wild-type TRPM6. Changing the residue I1030 into methionine, resulted in channels with lower conductance for Ni2+, decreased sensitivity to ruthenium red block and reduced pore diameter. Thus, these data demonstrate that amino acid residues E1024, I1030 and D1031 are important for channel function and that subtle amino acid variation in the pore region accounts for TRPM6 permeation properties.
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Affiliation(s)
- Catalin N Topala
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, The Netherlands
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47
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Riveira-Munoz E, Chang Q, Godefroid N, Hoenderop JG, Bindels RJ, Dahan K, Devuyst O. Transcriptional and functional analyses of SLC12A3 mutations: new clues for the pathogenesis of Gitelman syndrome. J Am Soc Nephrol 2007; 18:1271-83. [PMID: 17329572 DOI: 10.1681/asn.2006101095] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Gitelman syndrome (GS) is a recessive salt-losing tubulopathy that is caused by mutations in the SLC12A3 gene that encodes the sodium-chloride co-transporter (NCC). GS is characterized by significant inter- and intrafamilial phenotype variability, with early onset and/or severe clinical manifestations in some patients. No correlations between the disease variability and the position/nature of SLC12A3 mutations have been investigated thus far. In this study, extensive mutational analyses of SLC12A3 were performed in 27 patients with GS, including genomic DNA sequencing, multiplex ligation-dependent probe amplification, cDNA analysis, and quantification of allele-specific transcripts, in parallel with functional analyses in Xenopus laevis oocytes and detailed phenotyping. Twenty-six SLC12A3 mutations were identified in 25 patients with GS, including eight novel (detection rate 80%). Transcript analysis demonstrated that splicing mutations of SLC12A3 lead to frameshifted mRNA subject to degradation by nonsense-mediated decay. Heterologous expression documented a novel class of NCC mutants with defective intrinsic transport activity. A subgroup of patients presented with early onset, growth retardation, and/or detrimental manifestations, confirming the potential severity of GS. The mutations that were associated with a severe presentation were the combination at least for one allele of a missplicing resulting in a truncated transcript that was downregulated by nonsense-mediated decay or a nonfunctional, cell surface-absent mutant. The most recurrent mutation on the second allele was a newly described NCC mutant that affected the functional properties of the co-transporter. These data suggest that the nature/position of SLC12A3 mutation, combined with male gender, is a determinant factor in the severity of GS and provide new insights in the underlying pathogenic mechanisms of the disease.
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Affiliation(s)
- Eva Riveira-Munoz
- Division of Nephrology, Université Catholique de Louvain Medical School, Brussels, Belgium
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48
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Lambers TT, Oancea E, de Groot T, Topala CN, Hoenderop JG, Bindels RJ. Extracellular pH dynamically controls cell surface delivery of functional TRPV5 channels. Mol Cell Biol 2006; 27:1486-94. [PMID: 17178838 PMCID: PMC1800733 DOI: 10.1128/mcb.01468-06] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extracellular pH has long been known to affect the rate and magnitude of ion transport processes among others via regulation of ion channel activity. The Ca(2+)-selective transient receptor potential vanilloid 5 (TRPV5) channel constitutes the apical entry gate in Ca(2+)-transporting cells, contributing significantly to the overall Ca(2+) balance. Here, we demonstrate that extracellular pH determines the cell surface expression of TRPV5 via a unique mechanism. By a comprehensive approach using total internal reflection fluorescence microscopy, cell surface protein labeling, electrophysiology, (45)Ca(2+) uptake assays, and functional channel recovery after chemobleaching, this study shows that upon extracellular alkalinization, a pool of TRPV5-containing vesicles is rapidly recruited to the cell surface without collapsing into the plasma membrane. These vesicles contain functional TRPV5 channels since extracellular alkalinization is accompanied by increased TRPV5 activity. Conversely, upon subsequent extracellular acidification, vesicles are retrieved from the plasma membrane, simultaneously resulting in decreased TRPV5 activity. Thus, TRPV5 accesses the extracellular compartment via transient openings of vesicles, suggesting that rapid responses of constitutive active TRP channels to physiological stimuli rely on vesicular "kiss and linger" interactions with the plasma membrane.
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Affiliation(s)
- Tim T Lambers
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
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49
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Abstract
The epithelial Ca(2+) channels TRPV5 and TRPV6 constitute the apical Ca(2+) entry pathway in the process of active Ca(2+) (re)absorption. By yeast two-hybrid and glutathione S-transferase pulldown analysis we identified RGS2 as a novel TRPV6-associated protein. RGS proteins determine the inactivation kinetics of heterotrimeric G-protein-coupled receptor (GPCR) signaling by regulating the GTPase activity of G(alpha) subunits. Here we demonstrate that TRPV6 interacts with the NH(2)-terminal domain of RGS2 in a Ca(2+)-independent fashion and that overexpression of RGS2 reduces the Na(+) and Ca(2+) current of TRPV6 but not that of TRPV5-transfected human embryonic kidney 293 (HEK293) cells. In contrast, overexpression of the deletion mutant DeltaN-RGS2, lacking the NH(2)-terminal domain of RGS2, in TRPV6-expressing HEK293 cells did not show this inhibition. Furthermore, cell surface biotinylation indicated that the inhibitory effect of RGS2 on TRPV6 activity is not mediated by differences in trafficking or retrieval of TRPV6 from the plasma membrane. This effect probably results from the direct interaction between RGS2 and TRPV6, affecting the gating properties of the channel. Finally, the scaffolding protein spinophilin, shown to recruit RGS2 and regulate GPCR-signaling via G(alpha), did not affect RGS2 binding and electrophysiological properties of TRPV6, indicating a GPCR-independent mechanism of TRPV6 regulation by RGS2.
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Affiliation(s)
- Joost P Schoeber
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen 6500 HB, The Netherlands
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50
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Gkika D, Hsu YJ, van der Kemp AW, Christakos S, Bindels RJ, Hoenderop JG. Critical Role of the Epithelial Ca2+Channel TRPV5 in Active Ca2+Reabsorption as Revealed by TRPV5/Calbindin-D28KKnockout Mice. J Am Soc Nephrol 2006; 17:3020-7. [PMID: 17005931 DOI: 10.1681/asn.2006060676] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [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] [Indexed: 11/03/2022] Open
Abstract
The epithelial Ca(2+) channel TRPV5 facilitates apical Ca(2+) entry during active Ca(2+) reabsorption in the distal convoluted tubule. In this process, cytosolic Ca(2+) remains at low nontoxic concentrations because the Ca(2+) influx is buffered rapidly by calbindin-D(28K). Subsequently, Ca(2+) that is bound to calbindin-D(28K) is shuttled toward the basolateral Ca(2+) extrusion systems. For addressing the in vivo role of TRPV5 and calbindin-D(28K) in the maintenance of the Ca(2+) balance, single- and double-knockout mice of TRPV5 and calbindin-D(28K) (TRPV5(-/-), calbindin-D(28K)(-/-), and TRPV5(-/-)/calbindin-D(28K)(-/-)) were characterized. These mice strains were fed two Ca(2+) diets (0.02 and 2% wt/wt) to investigate the influence of dietary Ca(2+) content on the Ca(2+) balance. Urine analysis indicated that TRPV5(-/-)/calbindin-D(28K)(-/-) mice exhibit on both diets hypercalciuria compared with wild-type mice. Ca(2+) excretion in TRPV5(-/-)/calbindin-D(28K)(-/-) mice was not significantly different from TRPV5(-/-) mice, whereas calbindin-D(28K)(-/-) mice did not show hypercalciuria. The similarity between TRPV5(-/-)/calbindin-D(28K)(-/-) and TRPV5(-/-) mice was supported further by an equivalent increase in renal calbindin-D(9K) expression and in intestinal Ca(2+) hyperabsorption as a result of upregulation of calbindin-D(9K) and TRPV6 expression in the duodenum. Elevated serum parathyroid hormone and 1,25-dihydroxyvitamin D(3) levels accompanied the enhanced expression of the Ca(2+) transporters. Intestinal Ca(2+) absorption and expression of calbindin-D(9K) and TRPV6, as well as serum parameters of the calbindin-D(28K)(-/-) mice, did not differ from those of wild-type mice. These results underline the gatekeeper function of TRPV5 being the rate-limiting step in active Ca(2+) reabsorption, unlike calbindin-D(28K), which possibly is compensated by calbindin-D(9K).
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Affiliation(s)
- Dimitra Gkika
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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