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Rioux AV, Nsimba-Batomene TR, Slimani S, Bergeron NAD, Gravel MAM, Schreiber SV, Fiola MJ, Haydock L, Garneau AP, Isenring P. Navigating the multifaceted intricacies of the Na +-Cl - cotransporter, a highly regulated key effector in the control of hydromineral homeostasis. Physiol Rev 2024; 104:1147-1204. [PMID: 38329422 DOI: 10.1152/physrev.00027.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 01/01/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024] Open
Abstract
The Na+-Cl- cotransporter (NCC; SLC12A3) is a highly regulated integral membrane protein that is known to exist as three splice variants in primates. Its primary role in the kidney is to mediate the cosymport of Na+ and Cl- across the apical membrane of the distal convoluted tubule. Through this role and the involvement of other ion transport systems, NCC allows the systemic circulation to reclaim a fraction of the ultrafiltered Na+, K+, Cl-, and Mg+ loads in exchange for Ca2+ and [Formula: see text]. The physiological relevance of the Na+-Cl- cotransport mechanism in humans is illustrated by several abnormalities that result from NCC inactivation through the administration of thiazides or in the setting of hereditary disorders. The purpose of the present review is to discuss the molecular mechanisms and overall roles of Na+-Cl- cotransport as the main topics of interest. On reading the narrative proposed, one will realize that the knowledge gained in regard to these themes will continue to progress unrelentingly no matter how refined it has now become.
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Affiliation(s)
- A V Rioux
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - T R Nsimba-Batomene
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - S Slimani
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - N A D Bergeron
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - M A M Gravel
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - S V Schreiber
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - M J Fiola
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - L Haydock
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
- Service de Néphrologie-Transplantation Rénale Adultes, Hôpital Necker-Enfants Malades, AP-HP, INSERM U1151, Université Paris Cité, Paris, France
| | - A P Garneau
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
- Service de Néphrologie-Transplantation Rénale Adultes, Hôpital Necker-Enfants Malades, AP-HP, INSERM U1151, Université Paris Cité, Paris, France
| | - P Isenring
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
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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] [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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Wang Y, Xiao X, Lin Q, Song R, Wang X, Liang Y, Chen J, Luan X, Zhou Z, Xiao Y, Xue Y, Hu J. Hepatocyte nuclear factor 1B deletion, but not intragenic mutation, might be more susceptible to hypomagnesemia. J Diabetes Investig 2024; 15:121-130. [PMID: 37737534 PMCID: PMC10759714 DOI: 10.1111/jdi.14084] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 08/15/2023] [Accepted: 08/24/2023] [Indexed: 09/23/2023] Open
Abstract
AIMS HNF1B syndrome is caused by defects in the hepatocyte nuclear factor 1B (HNF1B) gene, which leads to maturity-onset diabetes of the young type 5 and congenital organ malformations. This study aimed to identify a gene defect in a patient presenting with diabetes and severe diarrhea, while also analyzing the prevalence of hypomagnesemia and its correlation with the HNF1B genotype. MATERIALS AND METHODS Whole exome sequencing was used to identify responsible point mutations and small indels in the proband and their family members. Multiplex ligation-dependent probe amplification was carried out to identify HNF1B deletions. Furthermore, an analysis of published data on 539 cumulative HNF1B cases, from 29 literature sources, was carried out to determine the correlation between the HNF1B genotype and the phenotype of serum magnesium status. RESULTS Using multiplex ligation-dependent probe amplification, we identified a de novo heterozygous HNF1B deletion in the patient, who showed dorsal pancreas agenesis and multiple kidney cysts, as detected by magnetic resonance imaging. Magnesium supplementation effectively alleviated the symptoms of diarrhea. Hypomagnesemia was highly prevalent in 192 out of 354 (54.2%) patients with HNF1B syndrome. Compared with patients with intragenic mutations, those with HNF1B deletions were more likely to suffer from hypomagnesemia, with an odds ratio of 3.1 (95% confidence interval 1.8-5.4). CONCLUSIONS Hypomagnesemia is highly prevalent in individuals with HNF1B syndrome, and those with HNF1B deletion are more susceptible to developing hypomagnesemia compared with those with intragenic mutations. The genotype-phenotype associations in HNF1B syndrome have significant implications for endocrinologists in terms of genotype detection, treatment decisions and prognosis assessment.
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Affiliation(s)
- Yanfei Wang
- Department of Endocrinology and Metabolism, Nanfang HospitalSouthern Medical UniversityGuangzhouChina
- Department of EndocrinologyThe First People's Hospital of FoshanFoshanChina
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and EndocrinologyThe Second Xiangya Hospital of Central South UniversityChangshaChina
| | - Xiaoyu Xiao
- Department of Metabolism and Endocrinology, The Xiangya HospitalCentral South UniversityChangshaChina
| | - Qiuqiu Lin
- Shunde HospitalSouthern Medical UniversityFoshanChina
| | - Rong Song
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and EndocrinologyThe Second Xiangya Hospital of Central South UniversityChangshaChina
| | - Xiaozhou Wang
- Department of EndocrinologyThe First People's Hospital of FoshanFoshanChina
| | - Yiji Liang
- Department of EndocrinologyThe First People's Hospital of FoshanFoshanChina
| | - Jingsong Chen
- Department of EndocrinologyThe First People's Hospital of FoshanFoshanChina
| | - Xiaojun Luan
- Department of EndocrinologyThe First People's Hospital of FoshanFoshanChina
| | - Zhiguang Zhou
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and EndocrinologyThe Second Xiangya Hospital of Central South UniversityChangshaChina
| | - Yang Xiao
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and EndocrinologyThe Second Xiangya Hospital of Central South UniversityChangshaChina
| | - Yaoming Xue
- Department of Endocrinology and Metabolism, Nanfang HospitalSouthern Medical UniversityGuangzhouChina
| | - Jingyi Hu
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and EndocrinologyThe Second Xiangya Hospital of Central South UniversityChangshaChina
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Grand K, Stoltz M, Rizzo L, Röck R, Kaminski MM, Salinas G, Getwan M, Naert T, Pichler R, Lienkamp SS. HNF1B Alters an Evolutionarily Conserved Nephrogenic Program of Target Genes. J Am Soc Nephrol 2023; 34:412-432. [PMID: 36522156 PMCID: PMC10103355 DOI: 10.1681/asn.2022010076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 10/11/2022] [Accepted: 11/09/2022] [Indexed: 12/23/2022] Open
Abstract
SIGNIFICANCE STATEMENT Mutations in hepatocyte nuclear factor-1 β ( HNF1B ) are the most common monogenic causes of congenital renal malformations. HNF1B is necessary to directly reprogram fibroblasts to induced renal tubule epithelial cells (iRECs) and, as we demonstrate, can induce ectopic pronephric tissue in Xenopus ectodermal organoids. Using these two systems, we analyzed the effect of HNF1B mutations found in patients with cystic dysplastic kidney disease. We found cross-species conserved targets of HNF1B, identified transcripts that are differentially regulated by the patient-specific mutant protein, and functionally validated novel HNF1B targets in vivo . These results highlight evolutionarily conserved transcriptional mechanisms and provide insights into the genetic circuitry of nephrogenesis. BACKGROUND Hepatocyte nuclear factor-1 β (HNF1B) is an essential transcription factor during embryogenesis. Mutations in HNF1B are the most common monogenic causes of congenital cystic dysplastic renal malformations. The direct functional consequences of mutations in HNF1B on its transcriptional activity are unknown. METHODS Direct reprogramming of mouse fibroblasts to induced renal tubular epithelial cells was conducted both with wild-type HNF1B and with patient mutations. HNF1B was expressed in Xenopus ectodermal explants. Transcriptomic analysis by bulk RNA-Seq identified conserved targets with differentially regulated expression by the wild-type or R295C mutant. CRISPR/Cas9 genome editing in Xenopus embryos evaluated transcriptional targets in vivo . RESULTS HNF1B is essential for reprogramming mouse fibroblasts to induced renal tubular epithelial cells and induces development of ectopic renal organoids from pluripotent Xenopus cells. The mutation R295C retains reprogramming and inductive capacity but alters the expression of specific sets of downstream target genes instead of diminishing overall transcriptional activity of HNF1B. Surprisingly, targets associated with polycystic kidney disease were less affected than genes affected in congenital renal anomalies. Cross-species-conserved transcriptional targets were dysregulated in hnf1b CRISPR-depleted Xenopus embryos, confirming their dependence on hnf1b . CONCLUSIONS HNF1B activates an evolutionarily conserved program of target genes that disease-causing mutations selectively disrupt. These findings provide insights into the renal transcriptional network that controls nephrogenesis.
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Affiliation(s)
- Kelli Grand
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Martine Stoltz
- The University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ludovica Rizzo
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Ruth Röck
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Michael M. Kaminski
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
| | | | - Maike Getwan
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Thomas Naert
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Roman Pichler
- The University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Soeren S. Lienkamp
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- The University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Abstract
Mg2+ is essential for many cellular and physiological processes, including muscle contraction, neuronal activity, and metabolism. Consequently, the blood Mg2+ concentration is tightly regulated by balanced intestinal Mg2+ absorption, renal Mg2+ excretion, and Mg2+ storage in bone and soft tissues. In recent years, the development of novel transgenic animal models and identification of Mendelian disorders has advanced our current insight in the molecular mechanisms of Mg2+ reabsorption in the kidney. In the proximal tubule, Mg2+ reabsorption is dependent on paracellular permeability by claudin-2/12. In the thick ascending limb of Henle's loop, the claudin-16/19 complex provides a cation-selective pore for paracellular Mg2+ reabsorption. The paracellular Mg2+ reabsorption in this segment is regulated by the Ca2+-sensing receptor, parathyroid hormone, and mechanistic target of rapamycin (mTOR) signaling. In the distal convoluted tubule, the fine tuning of Mg2+ reabsorption takes place by transcellular Mg2+ reabsorption via transient receptor potential melastatin-like types 6 and 7 (TRPM6/TRPM7) divalent cation channels. Activity of TRPM6/TRPM7 is dependent on hormonal regulation, metabolic activity, and interacting proteins. Basolateral Mg2+ extrusion is still poorly understood but is probably dependent on the Na+ gradient. Cyclin M2 and SLC41A3 are the main candidates to act as Na+/Mg2+ exchangers. Consequently, disturbances of basolateral Na+/K+ transport indirectly result in impaired renal Mg2+ reabsorption in the distal convoluted tubule. Altogether, this review aims to provide an overview of the molecular mechanisms of Mg2+ reabsorption in the kidney, specifically focusing on transgenic mouse models and human hereditary diseases.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
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Tholen LE, Latta F, Martens JHA, Hoenderop JGJ, de Baaij JHF. Transcription factor HNF1β controls a transcriptional network regulating kidney cell structure and tight junction integrity. Am J Physiol Renal Physiol 2023; 324:F211-F224. [PMID: 36546837 DOI: 10.1152/ajprenal.00199.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mutations in the hepatocyte nuclear factor (HNF)1β gene (HNF1B) cause autosomal dominant tubulointerstitial kidney disease, a rare and heterogeneous disease characterized by renal cysts and/or malformation, maturity-onset diabetes of the young, hypomagnesemia, and hypokalemia. The electrolyte disturbances may develop in the distal part of the nephron, which is important for fine-tuning of Mg2+ and Ca2+ reabsorption. Therefore, we aimed to study the transcriptional network directed by HNF1β in the distal part of the nephron. We combined HNF1β chromatin immunoprecipitation-sequencing and mRNA expression data to identify direct targets of HNF1β in a renal distal convoluted tubule cell line (mpkDCT). Gene Ontology term pathway analysis demonstrated enrichment of cell polarity, cell-cell junction, and cytoskeleton pathways in the dataset. Genes directly and indirectly regulated by HNF1β within these pathways included members of the apical and basolateral polarity complexes including Crumbs protein homolog 3 (Crb3), partitioning defective 6 homolog-β (Pard6b), and LLGL Scribble cell polarity complex component 2 (Llgl2). In monolayers of mouse inner medullary collecting duct 3 cells expressing dominant negative Hnf1b, tight junction integrity was compromised, as observed by reduced transepithelial electrical resistance values and increased permeability for fluorescein (0.4 kDa) compared with wild-type cells. Expression of dominant negative Hnf1b also led to a decrease in height (30%) and an increase in surface (58.5%) of cells grown on membranes. Moreover, three-dimensional spheroids formed by cells expressing dominant negative Hnf1b were reduced in size compared with wild-type spheroids (30%). Together, these findings demonstrate that HNF1β directs a transcriptional network regulating tight junction integrity and cell structure in the distal part of the nephron.NEW & NOTEWORTHY Genetic defects in transcription factor hepatocyte nuclear factor (HNF)1β cause a heterogeneous disease characterized by electrolyte disturbances, kidney cysts, and diabetes. By combining RNA-sequencing and HNF1β chromatin immunoprecipitation-sequencing data, we identified new HNF1β targets that were enriched for cell polarity pathways. Newly discovered targets included members of polarity complexes Crb3, Pard6b, and Llgl2. Functional assays in kidney epithelial cells demonstrated decreased tight junction integrity and a loss of typical cuboidal morphology in mutant Hnf1b cells.
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Affiliation(s)
- Lotte E Tholen
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Femke Latta
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost H A Martens
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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7
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Tholen LE, Schigt H, Kleuskens SGE, Bos C, Spruijt CG, Willemsen B, Vermeulen M, Hoenderop JGJ, de Baaij JHF. HNF1β-associated cyst development and electrolyte disturbances are not explained by BAIAP2L2 expression. FASEB J 2023; 37:e22696. [PMID: 36520027 DOI: 10.1096/fj.202201121r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/21/2022] [Accepted: 11/28/2022] [Indexed: 12/16/2022]
Abstract
Mutations or deletions in transcription factor hepatocyte nuclear factor 1 homeobox β (HNF1β) cause renal cysts and/or malformation, maturity-onset diabetes of the young and electrolyte disturbances. Here, we applied a comprehensive bioinformatic approach on ChIP-seq, RNA-seq, and gene expression array studies to identify novel transcriptional targets of HNF1β explaining the kidney phenotype of HNF1β patients. We identified BAR/IMD Domain Containing Adaptor Protein 2 Like 2 (BAIAP2L2), as a novel transcriptional target of HNF1β and validated direct transcriptional activation of the BAIAP2L2 promoter by a reporter luciferase assay. Using mass spectrometry analysis, we show that BAIAP2L2 binds to other members of the I-BAR domain-containing family: BAIAP2 and BAIAP2L1. Subsequently, the role of BAIAP2L2 in maintaining epithelial cell integrity in the kidney was assessed using Baiap2l2 knockout cell and mouse models. Kidney epithelial cells lacking functional BAIAP2L2 displayed normal F-actin distribution at cell-cell contacts and formed polarized three-dimensional spheroids with a lumen. In vivo, Baiap2l2 knockout mice displayed normal kidney and colon tissue morphology and serum and urine electrolyte concentrations were not affected. Altogether, our study is the first to characterize the function of BAIAP2L2 in the kidney in vivo and we report that mice lacking BAIAP2L2 exhibit normal electrolyte homeostasis and tissue morphology under physiological conditions.
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Affiliation(s)
- Lotte E Tholen
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Heidi Schigt
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sanne G E Kleuskens
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Caro Bos
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cornelia G Spruijt
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Brigith Willemsen
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Kim GH, Jun JB. Altered Serum Uric Acid Levels in Kidney Disorders. LIFE (BASEL, SWITZERLAND) 2022; 12:life12111891. [PMID: 36431026 PMCID: PMC9692609 DOI: 10.3390/life12111891] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/07/2022] [Accepted: 11/13/2022] [Indexed: 11/17/2022]
Abstract
Serum uric acid levels are altered by kidney disorders because the kidneys play a dominant role in uric acid excretion. Here, major kidney disorders which accompany hyperuricemia or hypouricemia, including their pathophysiology, are discussed. Chronic kidney disease (CKD) and hyperuricemia are frequently associated, but recent clinical trials have not supported the pathogenic roles of hyperuricemia in CKD incidence and progression. Diabetes mellitus (DM) is often associated with hyperuricemia, and hyperuricemia may be associated with an increased risk of diabetic kidney disease in patients with type 2 DM. Sodium-glucose cotransporter 2 inhibitors have a uricosuric effect and can relieve hyperuricemia in DM. Autosomal dominant tubulointerstitial kidney disease (ADTKD) is an important hereditary kidney disease, mainly caused by mutations of uromodulin (UMOD) or mucin-1 (MUC-1). Hyperuricemia and gout are the major clinical manifestations of ADTKD-UMOD and ADTKD-MUC1. Renal hypouricemia is caused by URAT1 or GLUT9 loss-of-function mutations and renders patients susceptible to exercise-induced acute kidney injury, probably because of excessive urinary uric acid excretion. Hypouricemia derived from renal uric acid wasting is a component of Fanconi syndrome, which can be hereditary or acquired. During treatment for human immunodeficiency virus, hepatitis B or cytomegalovirus, tenofovir, adefovir, and cidofovir may cause drug-induced renal Fanconi syndrome. In coronavirus disease 2019, hypouricemia due to proximal tubular injury is related to disease severity, including respiratory failure. Finally, serum uric acid and the fractional excretion of uric acid are indicative of plasma volume status; hyperuricemia caused by the enhanced uric acid reabsorption can be induced by volume depletion, and hypouricemia caused by an increased fractional excretion of uric acid is the characteristic finding in syndromes of inappropriate anti-diuresis, cerebral/renal salt wasting, and thiazide-induced hyponatremia. Molecular mechanisms by which uric acid transport is dysregulated in volume or water balance disorders need to be investigated.
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Affiliation(s)
- Gheun-Ho Kim
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul 04763, Republic of Korea
- Correspondence: ; Tel.: +82-2-2290-8318
| | - Jae-Bum Jun
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul 04763, Republic of Korea
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9
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Abstract
PURPOSE OF REVIEW Gitelman syndrome is a recessive salt-wasting disorder characterized by hypomagnesemia, hypokalemia, metabolic alkalosis and hypocalciuria. The majority of patients are explained by mutations and deletions in the SLC12A3 gene, encoding the Na+-Cl--co-transporter (NCC). Recently, additional genetic causes of Gitelman-like syndromes have been identified that should be considered in genetic screening. This review aims to provide a comprehensive overview of the clinical, genetic and mechanistic aspects of Gitelman(-like) syndromes. RECENT FINDINGS Disturbed Na+ reabsorption in the distal convoluted tubule (DCT) is associated with hypomagnesemia and hypokalemic alkalosis. In Gitelman syndrome, loss-of-function mutations in SLC12A3 cause impaired NCC-mediated Na+ reabsorption. In addition, patients with mutations in CLCKNB, KCNJ10, FXYD2 or HNF1B may present with a similar phenotype, as these mutations indirectly reduce NCC activity. Furthermore, genetic investigations of patients with Na+-wasting tubulopathy have resulted in the identification of pathogenic variants in MT-TI, MT-TF, KCNJ16 and ATP1A1. These novel findings highlight the importance of cell metabolism and basolateral membrane potential for Na+ reabsorption in the DCT. SUMMARY Altogether, these findings extend the genetic spectrum of Gitelman-like electrolyte alterations. Genetic testing of patients with hypomagnesemia and hypokalemia should cover a panel of genes involved in Gitelman-like syndromes, including the mitochondrial genome.
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Affiliation(s)
- Karl P Schlingmann
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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10
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Framework From a Multidisciplinary Approach for Transitioning Variants of Unknown Significance From Clinical Genetic Testing in Kidney Disease to a Definitive Classification. Kidney Int Rep 2022; 7:2047-2058. [PMID: 36090499 PMCID: PMC9459028 DOI: 10.1016/j.ekir.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/20/2022] [Indexed: 11/21/2022] Open
Abstract
Introduction Monogenic causes in over 300 kidney-associated genes account for approximately 12% of end stage kidney disease (ESKD) cases. Advances in sequencing and large customized panels enable the noninvasive diagnosis of monogenic kidney disease at relatively low cost, thereby allowing for more precise management for patients and their families. A major challenge is interpreting rare variants, many of which are classified as variants of unknown significance (VUS). We present a framework in which we thoroughly evaluated and provided evidence of pathogenicity for HNF1B-p.Arg303His, a VUS returned from clinical diagnostic testing for a kidney transplant candidate. Methods A blueprint was designed by a multidisciplinary team of clinicians, molecular biologists, and diagnostic geneticists. The blueprint included using a health system-based cohort with genetic and clinical information to perform deep phenotyping of VUS heterozygotes to identify the candidate VUS and rule out other VUS, examination of existing genetic databases, as well as functional testing. Results Our approach demonstrated evidence for pathogenicity for HNF1B-p.Arg303His by showing similar burden of kidney manifestations in this variant to known HNF1B pathogenic variants, and greater burden compared to noncarriers. Conclusion Determination of a molecular diagnosis for the example family allows for proper surveillance and management of HNF1B-related manifestations such as kidney disease, diabetes, and hypomagnesemia with important implications for safe living-related kidney donation. The candidate gene-variant pair also allows for clinical biomarker testing for aberrations of linked pathways. This working model may be applicable to other diseases of genetic etiology.
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11
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Viering D, Schlingmann KP, Hureaux M, Nijenhuis T, Mallett A, Chan MM, van Beek A, van Eerde AM, Coulibaly JM, Vallet M, Decramer S, Pelletier S, Klaus G, Kömhoff M, Beetz R, Patel C, Shenoy M, Steenbergen EJ, Anderson G, Bongers EM, Bergmann C, Panneman D, Rodenburg RJ, Kleta R, Houillier P, Konrad M, Vargas-Poussou R, Knoers NV, Bockenhauer D, de Baaij JH. Gitelman-Like Syndrome Caused by Pathogenic Variants in mtDNA. J Am Soc Nephrol 2022; 33:305-325. [PMID: 34607911 PMCID: PMC8819995 DOI: 10.1681/asn.2021050596] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/06/2021] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Gitelman syndrome is the most frequent hereditary salt-losing tubulopathy characterized by hypokalemic alkalosis and hypomagnesemia. Gitelman syndrome is caused by biallelic pathogenic variants in SLC12A3, encoding the Na+-Cl- cotransporter (NCC) expressed in the distal convoluted tubule. Pathogenic variants of CLCNKB, HNF1B, FXYD2, or KCNJ10 may result in the same renal phenotype of Gitelman syndrome, as they can lead to reduced NCC activity. For approximately 10 percent of patients with a Gitelman syndrome phenotype, the genotype is unknown. METHODS We identified mitochondrial DNA (mtDNA) variants in three families with Gitelman-like electrolyte abnormalities, then investigated 156 families for variants in MT-TI and MT-TF, which encode the transfer RNAs for phenylalanine and isoleucine. Mitochondrial respiratory chain function was assessed in patient fibroblasts. Mitochondrial dysfunction was induced in NCC-expressing HEK293 cells to assess the effect on thiazide-sensitive 22Na+ transport. RESULTS Genetic investigations revealed four mtDNA variants in 13 families: m.591C>T (n=7), m.616T>C (n=1), m.643A>G (n=1) (all in MT-TF), and m.4291T>C (n=4, in MT-TI). Variants were near homoplasmic in affected individuals. All variants were classified as pathogenic, except for m.643A>G, which was classified as a variant of uncertain significance. Importantly, affected members of six families with an MT-TF variant additionally suffered from progressive chronic kidney disease. Dysfunction of oxidative phosphorylation complex IV and reduced maximal mitochondrial respiratory capacity were found in patient fibroblasts. In vitro pharmacological inhibition of complex IV, mimicking the effect of the mtDNA variants, inhibited NCC phosphorylation and NCC-mediated sodium uptake. CONCLUSION Pathogenic mtDNA variants in MT-TF and MT-TI can cause a Gitelman-like syndrome. Genetic investigation of mtDNA should be considered in patients with unexplained Gitelman syndrome-like tubulopathies.
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Affiliation(s)
- Daan Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Karl P. Schlingmann
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - Marguerite Hureaux
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies rénales héréditaires de l'enfant et de l'adulte [MARHEA]), Paris, France,Department of Genetics, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France
| | - Tom Nijenhuis
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Andrew Mallett
- Department of Renal Medicine, Townsville University Hospital, Townsville, Australia,Queensland Conjoint Renal Genetics Service – Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, Australia
| | - Melanie M.Y. Chan
- Department of Renal Medicine, University College London, London, United Kingdom
| | - André van Beek
- Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | | | - Marion Vallet
- Department of Physiological Functional Investigations, Centre Hospitalier Universitaire de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Stéphane Decramer
- Pediatric Nephrology, Internal Medicine and Rheumatology, Southwest Renal Rare Diseases Centre (SORARE), University Children's Hospital, Toulouse, France
| | - Solenne Pelletier
- Department of Nephrology, University Hospital–Lyon Sud, Lyon, France
| | - Günter Klaus
- Kuratorium für Heimdialyse Pediatric Kidney Center, Marburg, Germany
| | - Martin Kömhoff
- University Children's Hospital, Philipps-University, Marburg, Germany
| | - Rolf Beetz
- Johannes Gutenberg Universität Mainz, Zentrum für Kinder- und Jugendmedizin, Mainz, Germany
| | - Chirag Patel
- Queensland Conjoint Renal Genetics Service – Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, Australia
| | - Mohan Shenoy
- Department of Paediatric Nephrology, Royal Manchester Children’s Hospital, Manchester, United Kingdom
| | - Eric J. Steenbergen
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Glenn Anderson
- Department of Pathology, Great Ormond Street Hospital for Children National Health Service (NHS) Foundation Trust, London, United Kingdom
| | - Ernie M.H.F. Bongers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Carsten Bergmann
- Limbach Genetics, Medizinische Genetik Mainz, Prof. Bergmann & Kollegen, Mainz, Germany,Department of Medicine, Division of Nephrology, University Hospital Freiburg, Germany
| | - Daan Panneman
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Richard J. Rodenburg
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Pascal Houillier
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies rénales héréditaires de l'enfant et de l'adulte [MARHEA]), Paris, France,Centre de Recherche des Cordeliers, Sorbonne Université, Institut National de la Santé et de Recherche Médicale (INSERM), Université de Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
| | - Martin Konrad
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies rénales héréditaires de l'enfant et de l'adulte [MARHEA]), Paris, France,Department of Genetics, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France,Centre de Recherche des Cordeliers, Sorbonne Université, Institut National de la Santé et de Recherche Médicale (INSERM), Université de Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Nine V.A.M. Knoers
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, United Kingdom,Renal Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Jeroen H.F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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12
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Ge S, Yang M, Gong W, Chen W, Dong J, Liao L. Case Report: A case of HNF1B mutation patient with first presentation of diabetic ketosis. Front Endocrinol (Lausanne) 2022; 13:917819. [PMID: 35992134 PMCID: PMC9388818 DOI: 10.3389/fendo.2022.917819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Maturity-onset diabetes of the young 5 (MODY5), a rare diabetes syndrome of young adults, is associated with variants in hepatocyte nuclear factor 1B (HNF1B) gene. CASE PRESENTATION We reported a case of MODY5, which presented with diabetic ketosis, multiple renal cysts, and hypokalemia. In this case, the HNF1B score was estimated as 13 and a heterozygous variant of HNF1B in exon 4 (c.826C>T, p.Arg276*) was identified through Sanger sequencing. CONCLUSIONS Multiple renal cysts and youth-onset diabetes are common manifestations in patients with HNF1B mutations, and insufficient insulin secretion may be a potential cause of diabetic ketosis in MODY5.
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Affiliation(s)
- Shenghui Ge
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
| | - Mengge Yang
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
- Cheeloo College of Medicine, Shandong University, Department of Endocrinology and Metabology, Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational medicine, Shandong Institute of Nephrology, Ji-nan, China
| | - Wenfeng Gong
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
| | - Wenzhe Chen
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
| | - Jianjun Dong
- Division of Endocrinology, Department of Internal Medicine, Qilu Hospital of Shandong University, Ji-nan, China
- *Correspondence: Lin Liao, ; Jianjun Dong,
| | - Lin Liao
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
- Cheeloo College of Medicine, Shandong University, Department of Endocrinology and Metabology, Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational medicine, Shandong Institute of Nephrology, Ji-nan, China
- *Correspondence: Lin Liao, ; Jianjun Dong,
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13
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Tseng MH, Konrad M, Ding JJ, Lin SH. Clinical and Genetic Approach to Renal Hypomagnesemia. Biomed J 2021; 45:74-87. [PMID: 34767995 PMCID: PMC9133307 DOI: 10.1016/j.bj.2021.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/03/2022] Open
Abstract
Magnesium (Mg2+) is an important intracellular cation and essential to maintain cell function including cell proliferation, immunity, cellular energy metabolism, protein and nucleic acid synthesis, and regulation of ion channels. Consequences of hypomagnesemia affecting multiple organs can be in overt or subtle presentations. Besides detailed history and complete physical examination, the assessment of urinary Mg2+ excretion is help to differentiate renal from extra-renal (gastrointestinal, tissue sequestration, and shifting) causes of hypomagnesemia. Renal hypomagnesemia can be caused by an increased glomerular filtration and impaired reabsorption in proximal tubular cells, thick ascending limb of the loop of Henle or distal convoluted tubules. A combination of renal Mg2+ wasting, familial history, age of onset, associated features, and exclusion of acquired etiologies point to inherited forms of renal hypomagnesemia. Based on clinical phenotypes, its definite genetic diagnosis can be simply grouped into specific, uncertain, and unknown gene mutations with a priority of genetic approach methods. An unequivocal molecular diagnosis could allow for prediction of clinical outcome, providing genetic counseling, avoiding unnecessary studies or interventions, and possibly uncovering the pathogenic mechanism. Given numerous identified genes responsible for Mg2+ transport in renal hypomagnesemia over the past two decades, several potential and specific molecular and cellular therapeutic strategies to correct hypomagnesemia are promising.
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Affiliation(s)
- Min-Hua Tseng
- Division of Nephrology, Department of Pediatrics, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan; Department of Pediatrics, Xiamen Chang Gung Hospital, China
| | - Martin Konrad
- Department of General Pediatrics, University Children's Hospital Münster, Münster, Germany
| | - Jhao-Jhuang Ding
- Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
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14
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Piedrafita A, Balayssac S, Casemayou A, Saulnier-Blache JS, Lucas A, Iacovoni JS, Breuil B, Chauveau D, Decramer S, Malet-Martino M, Schanstra JP, Faguer S. Hepatocyte nuclear factor-1β shapes the energetic homeostasis of kidney tubule cells. FASEB J 2021; 35:e21931. [PMID: 34653285 DOI: 10.1096/fj.202100782rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 08/28/2021] [Accepted: 09/02/2021] [Indexed: 12/17/2022]
Abstract
Energetic metabolism controls key steps of kidney development, homeostasis, and epithelial repair following acute kidney injury (AKI). Hepatocyte nuclear factor-1β (HNF-1β) is a master transcription factor that controls mitochondrial function in proximal tubule (PT) cells. Patients with HNF1B pathogenic variant display a wide range of kidney developmental abnormalities and progressive kidney fibrosis. Characterizing the metabolic changes in PT cells with HNF-1β deficiency may help to identify new targetable molecular hubs involved in HNF1B-related kidney phenotypes and AKI. Here, we combined 1 H-NMR-based metabolomic analysis in a murine PT cell line with CrispR/Cas9-induced Hnf1b invalidation (Hnf1b-/- ), clustering analysis, targeted metabolic assays, and datamining of published RNA-seq and ChIP-seq dataset to identify the role of HNF-1β in metabolism. Hnf1b-/- cells grown in normoxic conditions display intracellular ATP depletion, increased cytosolic lactate concentration, increased lipid droplet content, failure to use pyruvate for energetic purposes, increased levels of tricarboxylic acid (TCA) cycle intermediates and oxidized glutathione, and a reduction of TCA cycle byproducts, all features consistent with mitochondrial dysfunction and an irreversible switch toward glycolysis. Unsupervised clustering analysis showed that Hnf1b-/- cells mimic a hypoxic signature and that they cannot furthermore increase glycolysis-dependent energetic supply during hypoxic challenge. Metabolome analysis also showed alteration of phospholipid biosynthesis in Hnf1b-/- cells leading to the identification of Chka, the gene coding for choline kinase α, as a new putative target of HNF-1β. HNF-1β shapes the energetic metabolism of PT cells and HNF1B deficiency in patients could lead to a hypoxia-like metabolic state precluding further adaptation to ATP depletion following AKI.
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Affiliation(s)
- Alexis Piedrafita
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France.,Université Paul Sabatier - Toulouse 3, Toulouse, France.,Département de Néphrologie et Transplantation d'Organes, Centre de Référence des Maladies Rénales Rares, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Stéphane Balayssac
- Groupe de RMN Biomédicale, Laboratoire SPCMIB, UMR CNRS 5068, Université Paul Sabatier, Centre National de la Recherche Scientifique, Toulouse, France.,Laboratoire des Interaction Moléculaires et Réactivité Chimique et Photochimique (IMRCP), UMR 5623, Toulouse, France
| | - Audrey Casemayou
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France.,Université Paul Sabatier - Toulouse 3, Toulouse, France.,Département de Néphrologie et Transplantation d'Organes, Centre de Référence des Maladies Rénales Rares, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Jean-Sébastien Saulnier-Blache
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France.,Université Paul Sabatier - Toulouse 3, Toulouse, France
| | - Alexandre Lucas
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France
| | - Jason S Iacovoni
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France
| | - Benjamin Breuil
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France
| | - Dominique Chauveau
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France.,Université Paul Sabatier - Toulouse 3, Toulouse, France.,Département de Néphrologie et Transplantation d'Organes, Centre de Référence des Maladies Rénales Rares, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Stéphane Decramer
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France.,Université Paul Sabatier - Toulouse 3, Toulouse, France.,Service de Néphrologie, Médecine interne et Hypertension artérielle, Hôpital des Enfants, Centre de Référence des Maladies Rénales Rares, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Myriam Malet-Martino
- Groupe de RMN Biomédicale, Laboratoire SPCMIB, UMR CNRS 5068, Université Paul Sabatier, Centre National de la Recherche Scientifique, Toulouse, France
| | - Joost P Schanstra
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France.,Université Paul Sabatier - Toulouse 3, Toulouse, France
| | - Stanislas Faguer
- Institut National de la Santé et de la Recherche Médicale, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Hôpital Rangueil, Toulouse, France.,Université Paul Sabatier - Toulouse 3, Toulouse, France.,Département de Néphrologie et Transplantation d'Organes, Centre de Référence des Maladies Rénales Rares, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
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15
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Abstract
Magnesium (Mg2+) plays an essential role in many biological processes. Mg2+ deficiency is therefore associated with a wide range of clinical effects including muscle cramps, fatigue, seizures and arrhythmias. To maintain sufficient Mg2+ levels, (re)absorption of Mg2+ in the intestine and kidney is tightly regulated. Genetic defects that disturb Mg2+ uptake pathways, as well as drugs interfering with Mg2+ (re)absorption cause hypomagnesemia. The aim of this review is to provide an overview of the molecular mechanisms underlying genetic and drug-induced Mg2+ deficiencies. This leads to the identification of four main mechanisms that are affected by hypomagnesemia-causing mutations or drugs: luminal transient receptor potential melastatin type 6/7-mediated Mg2+ uptake, paracellular Mg2+ reabsorption in the thick ascending limb of Henle's loop, structural integrity of the distal convoluted tubule and Na+-dependent Mg2+ extrusion driven by the Na+/K+-ATPase. Our analysis demonstrates that genetic and drug-induced causes of hypomagnesemia share common molecular mechanisms. Targeting these shared pathways can lead to novel treatment options for patients with hypomagnesemia.
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16
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Tholen LE, Bos C, Jansen PWTC, Venselaar H, Vermeulen M, Hoenderop JGJ, de Baaij JHF. Bifunctional protein PCBD2 operates as a co-factor for hepatocyte nuclear factor 1β and modulates gene transcription. FASEB J 2021; 35:e21366. [PMID: 33749890 DOI: 10.1096/fj.202002022r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/16/2020] [Accepted: 12/28/2020] [Indexed: 11/11/2022]
Abstract
Hepatocyte nuclear factor 1β (HNF1β) is an essential transcription factor in development of the kidney, liver, and pancreas. HNF1β-mediated transcription of target genes is dependent on the cell type and the development stage. Nevertheless, the regulation of HNF1β function by enhancers and co-factors that allow this cell-specific transcription is largely unknown. To map the HNF1β interactome we performed mass spectrometry in a mouse kidney inner medullary collecting duct cell line. Pterin-4a-carbinolamine dehydratase 2 (PCBD2) was identified as a novel interaction partner of HNF1β. PCBD2 and its close homolog PCBD1 shuttle between the cytoplasm and nucleus to exert their enzymatic and transcriptional activities. Although both PCBD proteins share high sequence identity (48% and 88% in HNF1 recognition helix), their tissue expression patterns are unique. PCBD1 is most abundant in kidney and liver while PCBD2 is also abundant in lung, spleen, and adipose tissue. Using immunolocalization studies and biochemical analysis we show that in presence of HNF1β the nuclear localization of PCBD1 and PCBD2 increases significantly. Promoter luciferase assays demonstrate that co-factors PCBD1 and PCBD2 differentially regulate the ability of HNF1β to activate the promoters of transcriptional targets important in renal electrolyte homeostasis. Deleting the N-terminal sequence of PCBD2, not found in PCBD1, diminished the differential effects of the co-factors on HNF1β activity. All together these results indicate that PCBD1 and PCBD2 can exert different effects on HNF1β-mediated transcription. Future studies should confirm whether these unique co-factor activities also apply to HNF1β-target genes involved in additional processes besides ion transport in the kidney.
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Affiliation(s)
- Lotte E Tholen
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Caro Bos
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Pascal W T C Jansen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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17
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Genotype and Phenotype Analyses in Pediatric Patients with HNF1B Mutations. J Clin Med 2020; 9:jcm9072320. [PMID: 32708349 PMCID: PMC7408390 DOI: 10.3390/jcm9072320] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 01/01/2023] Open
Abstract
HNF1B mutations, one of the most common causes of congenital anomalies of the kidney and urinary tract, manifest as various renal and extrarenal phenotypes. We analyzed the genotype-phenotype correlations in 14 pediatric patients with HNF1B mutations. Genetic studies revealed total gene deletion in six patients (43%). All patients had bilateral renal abnormalities, primarily multiple renal cysts. Twelve patients exhibited progressive renal functional deterioration, and six of them progressed to kidney failure. The annual reduction in estimated glomerular filtration rate was−2.1 mL/min/1.73 m2. Diabetes developed in five patients (36%), including one patient with new-onset diabetes after transplantation. Neurological deficits were noted in three patients (21%), one with total gene deletion and two with missense mutations. Pancreatic abnormalities were more frequent in patients with missense mutations than in patients with other types of mutations. Genotype showed no significant correlation with renal outcomes or other extrarenal manifestations. The HNF1B scores at the times of onset and genetic diagnosis were <8 in two patients and one patient, respectively. Diagnosis of HNF1B mutations is clinically difficult because of extreme phenotypic variability and incomplete penetrance. Furthermore, some phenotypes develop with age. Therefore, patient age should be taken into consideration to increase the diagnostic rate, because some phenotypes develop with age.
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18
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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Li HJ, Groden C, Hoenig MP, Ray EC, Ferreira CR, Gahl W, Novacic D. Case report: extreme coronary calcifications and hypomagnesemia in a patient with a 17q12 deletion involving HNF1B. BMC Nephrol 2019; 20:353. [PMID: 31500578 PMCID: PMC6734489 DOI: 10.1186/s12882-019-1533-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 08/23/2019] [Indexed: 01/30/2023] Open
Abstract
Background 17q12 deletion syndrome encompasses a broad constellation of clinical phenotypes, including renal magnesium wasting, maturity-onset diabetes of the young (MODY), renal cysts, genitourinary malformations, and neuropsychiatric illness. Manifestations outside of the renal, endocrine, and nervous systems have not been well described. Case presentation We report a 62-year-old male referred to the Undiagnosed Diseases Program (UDP) at the National Institutes of Health (NIH) who presented with persistent hypermagnesiuric hypomagnesemia and was found to have a 17q12 deletion. The patient exhibited several known manifestations of the syndrome, including severe hypomagnesemia, renal cysts, diabetes and cognitive deficits. Coronary CT revealed extensive coronary calcifications, with a coronary artery calcification score of 12,427. Vascular calcifications have not been previously reported in this condition. We describe several physiologic mechanisms and a review of literature to support the expansion of the 17q12 deletion syndrome to include vascular calcification. Conclusion Extensive coronary and vascular calcifications may be an extension of the 17q12 deletion phenotype, particularly if hypomagnesemia and hyperparathyroidism are prevalent. In patients with 17q12 deletions involving HNF1B, hyperparathyroidism and hypomagnesemia may contribute to significant cardiovascular risk.
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Affiliation(s)
- Howard J Li
- Harvard Medical School, Boston, MA, 02115, USA.,National Institute of Mental Health, NIH, Bethesda, MD, 20892, USA
| | - Catherine Groden
- Undiagnosed Diseases Program, Office of the Clinical Director and National Human Genome Research Institute, NIH, Bethesda, MD, 20892, USA
| | - Melanie P Hoenig
- Harvard Medical School, Boston, MA, 02115, USA.,Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, MA, 02215, USA
| | - Evan C Ray
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Carlos R Ferreira
- Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Willam Gahl
- Undiagnosed Diseases Program, Office of the Clinical Director and National Human Genome Research Institute, NIH, Bethesda, MD, 20892, USA.,Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Danica Novacic
- Undiagnosed Diseases Program, Office of the Clinical Director and National Human Genome Research Institute, NIH, Bethesda, MD, 20892, USA.
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Abstract
Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a recently defined entity that includes rare kidney diseases characterized by tubular damage and interstitial fibrosis in the absence of glomerular lesions, with inescapable progression to end-stage renal disease. These diseases have long been neglected and under-recognized, in part due to confusing and inconsistent terminology. The introduction of a gene-based, unifying terminology led to the identification of an increasing number of cases, with recent data suggesting that ADTKD is one of the more common monogenic kidney diseases after autosomal dominant polycystic kidney disease, accounting for ~5% of monogenic disorders causing chronic kidney disease. ADTKD is caused by mutations in at least five different genes, including UMOD, MUC1, REN, HNF1B and, more rarely, SEC61A1. These genes encode various proteins with renal and extra-renal functions. The mundane clinical characteristics and lack of appreciation of family history often result in a failure to diagnose ADTKD. This Primer highlights the different types of ADTKD and discusses the distinct genetic and clinical features as well as the underlying mechanisms.
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Ferrè S, Igarashi P. New insights into the role of HNF-1β in kidney (patho)physiology. Pediatr Nephrol 2019; 34:1325-1335. [PMID: 29961928 PMCID: PMC6312759 DOI: 10.1007/s00467-018-3990-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/24/2018] [Accepted: 05/25/2018] [Indexed: 12/14/2022]
Abstract
Hepatocyte nuclear factor-1β (HNF-1β) is an essential transcription factor that regulates the development and function of epithelia in the kidney, liver, pancreas, and genitourinary tract. Humans who carry HNF1B mutations develop heterogeneous renal abnormalities, including multicystic dysplastic kidneys, glomerulocystic kidney disease, renal agenesis, renal hypoplasia, and renal interstitial fibrosis. In the embryonic kidney, HNF-1β is required for ureteric bud branching, initiation of nephrogenesis, and nephron segmentation. Ablation of mouse Hnf1b in nephron progenitors causes defective tubulogenesis, whereas later inactivation in elongating tubules leads to cyst formation due to downregulation of cystic disease genes, including Umod, Pkhd1, and Pkd2. In the adult kidney, HNF-1β controls the expression of genes required for intrarenal metabolism and solute transport by tubular epithelial cells. Tubular abnormalities observed in HNF-1β nephropathy include hyperuricemia with or without gout, hypokalemia, hypomagnesemia, and polyuria. Recent studies have identified novel post-transcriptional and post-translational regulatory mechanisms that control HNF-1β expression and activity, including the miRNA cluster miR17 ∼ 92 and the interacting proteins PCBD1 and zyxin. Further understanding of the molecular mechanisms upstream and downstream of HNF-1β may lead to the development of new therapeutic approaches in cystic kidney disease and other HNF1B-related renal diseases.
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Affiliation(s)
- Silvia Ferrè
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, Texas, USA,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Peter Igarashi
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Medicine, University of Minnesota Medical School, 420 Delaware St. SE, MMC 194, Minneapolis, MN, 55455, USA.
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22
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HNF1B nephropathy has a slow-progressive phenotype in childhood-with the exception of very early onset cases: results of the German Multicenter HNF1B Childhood Registry. Pediatr Nephrol 2019; 34:1065-1075. [PMID: 30666461 DOI: 10.1007/s00467-018-4188-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 11/06/2018] [Accepted: 12/20/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND HNF1B gene mutations are an important cause of bilateral (cystic) dysplasia in children, complicated by chronic renal insufficiency. The clinical variability, the absence of genotype-phenotype correlations, and limited long-term data render counseling of affected families difficult. METHODS Longitudinal data of 62 children probands with genetically proven HNF1B nephropathy was obtained in a multicenter approach. Genetic family cascade screening was performed in 30/62 cases. RESULTS Eighty-seven percent of patients had bilateral dysplasia, 74% visible bilateral, and 16% unilateral renal cysts at the end of observation. Cyst development was non-progressive in 72% with a mean glomerular filtration rate (GFR) loss of - 0.33 ml/min/1.73m2 per year (± 8.9). In patients with an increase in cyst number, the annual GFR reduction was - 2.8 ml/min/1.73m2 (± 13.2), in the total cohort - 1.0 ml/min/1.73m2 (±10.3). A subset of HNF1B patients differs from this group and develops end stage renal disease (ESRD) at very early ages < 2 years. Hyperuricemia (37%) was a frequent finding at young age (median 1 year), whereas hypomagnesemia (24%), elevated liver enzymes (21%), and hyperglycemia (8%) showed an increased incidence in the teenaged child. Genetic analysis revealed no genotype-phenotype correlations but a significant parent-of-origin effect with a preponderance of 81% of maternal inheritance in dominant cases. CONCLUSIONS In most children, HNF1B nephropathy has a non-progressive course of cyst development and a slow-progressive course of kidney function. A subgroup of patients developed ESRD at very young age < 2 years requiring special medical attention. The parent-of-origin effect suggests an influence of epigenetic modifiers in HNF1B disease.
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23
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Adalat S, Hayes WN, Bryant WA, Booth J, Woolf AS, Kleta R, Subtil S, Clissold R, Colclough K, Ellard S, Bockenhauer D. HNF1B Mutations Are Associated With a Gitelman-like Tubulopathy That Develops During Childhood. Kidney Int Rep 2019; 4:1304-1311. [PMID: 31517149 PMCID: PMC6732753 DOI: 10.1016/j.ekir.2019.05.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/29/2019] [Accepted: 05/20/2019] [Indexed: 12/20/2022] Open
Abstract
Background Mutations in the transcription factor hepatocyte nuclear factor 1B (HNF1B) are the most common inherited cause of renal malformations, yet also associated with renal tubular dysfunction, most prominently magnesium wasting with hypomagnesemia. The presence of hypomagnesemia has been proposed to help select appropriate patients for genetic testing. Yet, in a large cohort, hypomagnesemia was discriminatory only in adult, but not in pediatric patients. We therefore investigated whether hypomagnesemia and other biochemical changes develop with age. Methods We performed a retrospective analysis of clinical, biochemical, and genetic results of pediatric patients with renal malformations tested for HNF1B mutations, separated into 4 age groups. Values were excluded if concurrent estimated glomerular filtration rate (eGFR) was <30 ml/min per 1.73 m2, or after transplantation. Results A total of 199 patients underwent HNF1B genetic testing and mutations were identified in 52 (mut+). The eGFRs were comparable between mut+ and mut- in any age group. Although median plasma magnesium concentrations differed significantly between mut+ and mut- patients in all age groups, overt hypomagnesemia was not present until the second half of childhood in the mut+ group. There was also a significant difference in median potassium concentrations in late childhood with lower values in the mut+ cohort. Conclusions The abnormal tubular electrolyte handling associated with HNF1B mutations develops with age and is not restricted to magnesium, but consistent with a more generalized dysfunction of the distal convoluted tubule, reminiscent of Gitelman syndrome. The absence of these abnormalities in early childhood should not preclude HNF1B mutations from diagnostic considerations.
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Affiliation(s)
- Shazia Adalat
- Evelina Children’s Hospital, London, United Kingdom
- UCL Department of Renal Medicine, London, United Kingdom
| | - Wesley N. Hayes
- UCL Department of Renal Medicine, London, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - William A. Bryant
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - John Booth
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Adrian S. Woolf
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, United Kingdom
- Royal Manchester Children’s Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Robert Kleta
- UCL Department of Renal Medicine, London, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | | | - Rhian Clissold
- Royal Devon and Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Kevin Colclough
- Department of Molecular Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Sian Ellard
- Department of Molecular Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Detlef Bockenhauer
- UCL Department of Renal Medicine, London, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
- Correspondence: Detlef Bockenhauer, UCL Department of Renal Medicine, London WC1N 3JH, United Kingdom.
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Mayan H, Farfel Z, Karlish SJD. Renal Mg handling, FXYD2 and the central role of the Na,K-ATPase. Physiol Rep 2018; 6:e13843. [PMID: 30175537 PMCID: PMC6119663 DOI: 10.14814/phy2.13843] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/30/2018] [Accepted: 08/01/2018] [Indexed: 12/15/2022] Open
Abstract
This article examines the central role of Na,K-ATPase (α1β1FXYD2) in renal Mg handling, especially in distal convoluted tubule (DCT), the segment responsible for final regulation of Mg balance. By considering effects of Na,K-ATPase on intracellular Na and K concentrations, and driving forces for Mg transport, we propose a consistent rationale explaining basal Mg reabsorption in DCT and altered Mg reabsorption in some human diseases. FXYD2 (γ subunit) is a regulatory subunit that adapts functional properties of Na,K-ATPase to cellular requirements. Mutations in FXYD2 (G41R), and transcription factors (HNF-1B and PCBD1) that affect FXYD2 expression are associated with hypomagnesemia with hypermagnesuria. These mutations result in impaired interactions of FXYD2 with Na,K-ATPase. Renal Mg wasting implies that Na,K-ATPase is inhibited, but in vitro studies show that FXYD2 itself inhibits Na,K-ATPase activity, raising K0.5 Na. However, FXYD2 also stabilizes the protein by amplifying specific interactions with phosphatidylserine and cholesterol within the membrane. Renal Mg wasting associated with impaired Na,K-ATPase/FXYD2 interactions is explained simply by destabilization and inactivation of Na,K-ATPase. We consider also the role of the Na,K-ATPase in Mg (and Ca) handling in Gitelman syndrome and Familial hyperkalemia and hypertension (FHHt). Renal Mg handling serves as a convenient marker for Na,K-ATPase activity in DCT.
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Affiliation(s)
- Haim Mayan
- Department of Medicine ESheba Medical CenterRamat GanIsrael
- Laboratory of Biochemical PharmacologySheba Medical CenterRamat GanIsrael
- Sackler School of MedicineTel Aviv UniversityTel AvivIsrael
| | - Zvi Farfel
- Department of Medicine ESheba Medical CenterRamat GanIsrael
- Laboratory of Biochemical PharmacologySheba Medical CenterRamat GanIsrael
- Sackler School of MedicineTel Aviv UniversityTel AvivIsrael
- Department of Biomolecular SciencesWeizmann Institute of ScienceRehovothIsrael
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Kompatscher A, de Baaij JHF, Aboudehen K, Farahani S, van Son LHJ, Milatz S, Himmerkus N, Veenstra GC, Bindels RJM, Hoenderop JGJ. Transcription factor HNF1β regulates expression of the calcium-sensing receptor in the thick ascending limb of the kidney. Am J Physiol Renal Physiol 2018; 315:F27-F35. [DOI: 10.1152/ajprenal.00601.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mutations in hepatocyte nuclear factor 1β (HNF1β) cause autosomal dominant tubulointerstitial kidney disease (ADTKD-HNF1β), and patients tend to develop renal cysts, maturity-onset diabetes of the young (MODY), and suffer from electrolyte disturbances, including hypomagnesemia, hypokalemia, and hypocalciuria. Previous HNF1β research focused on the renal distal convoluted tubule (DCT) to elucidate the ADTKD-HNF1β electrolyte phenotype, although 70% of Mg2+ is reabsorbed in the thick ascending limb of Henle’s loop (TAL). An important regulator of Mg2+ reabsorption in the TAL is the calcium-sensing receptor (CaSR). This study used several methods to elucidate the role of HNF1β in electrolyte reabsorption in the TAL. HNF1β ChIP-seq data revealed a conserved HNF1β binding site in the second intron of the CaSR gene. Luciferase-promoter assays displayed a 5.8-fold increase in CaSR expression when HNF1β was present. Expression of the HNF1β p.Lys156Glu mutant, which prevents DNA binding, abolished CaSR expression. Hnf1β knockdown in an immortalized mouse kidney TAL cell line (MKTAL) reduced expression of the CaSR and Cldn14 (claudin 14) by 56% and 48%, respectively, while Cldn10b expression was upregulated 5.0-fold. These results were confirmed in a kidney-specific HNF1β knockout mouse, which exhibited downregulation of the Casr by 81%. Cldn19 and Cldn10b expression levels were also decreased by 37% and 83%, respectively, whereas Cldn3 was upregulated by 4.6-fold. In conclusion, HNF1β is a transcriptional activator of the CaSR. Consequently, patients with HNF1β mutations may have reduced CaSR activity in the kidney, which could explain cyst progression and hyperabsorption of Ca2+ and Mg2+ in the TAL resulting in hypocalciuria.
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Affiliation(s)
- Andreas Kompatscher
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H. F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Karam Aboudehen
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Shayan Farahani
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Lex H. J. van Son
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Susanne Milatz
- Institute of Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Gertjan C. Veenstra
- Department of Molecular Developmental Biology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - René J. M. Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G. J. Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Hsu IL, Chou CY, Wu YY, Wu JE, Liang CH, Tsai YT, Ke JY, Chen YL, Hsu KF, Hong TM. Targeting FXYD2 by cardiac glycosides potently blocks tumor growth in ovarian clear cell carcinoma. Oncotarget 2018; 7:62925-62938. [PMID: 26910837 PMCID: PMC5325337 DOI: 10.18632/oncotarget.7497] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 01/17/2016] [Indexed: 12/19/2022] Open
Abstract
Ovarian clear cell carcinoma (OCCC) is an aggressive neoplasm with a high recurrence rate that frequently develops resistance to platinum-based chemotherapy. There are few prognostic biomarkers or targeted therapies exist for patients with OCCC. Here, we identified that FXYD2, the modulating subunit of Na+/K+-ATPases, was highly and specifically expressed in clinical OCCC tissues. The expression levels of FXYD2 were significantly higher in advanced-stage of OCCC and positively correlated with patients' prognoses. Silencing of FXYD2 expression in OCCC cells inhibited Na+/K+-ATPase enzyme activity and suppressed tumor growth via induction of autophagy-mediated cell death. We found that high FXYD2 expression in OCCC was transcriptionally regulated by the transcriptional factor HNF1B. Furthermore, up-regulation of FXYD2 expression significantly increased the sensitivity of OCCC cells to cardiac glycosides, the Na+/K+-ATPase inhibitors. Two cardiac glycosides, digoxin and digitoxin, had a great therapeutic efficacy in OCCC cells in vitro and in vivo. Taken together, our results demonstrate that FXYD2 is functionally upregulated in OCCC and may serve as a promising prognostic biomarker and therapeutic target of cardiac glycosides in OCCC.
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Affiliation(s)
- I-Ling Hsu
- Institute of Basic Medical Sciences, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-Yang Chou
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Ying Wu
- Graduate Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jia-En Wu
- Institute of Basic Medical Sciences, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chen-Hsien Liang
- Institute of Basic Medical Sciences, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yao-Tsung Tsai
- Institute of Basic Medical Sciences, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jhen-Yu Ke
- Institute of Oral Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yuh-Ling Chen
- Institute of Basic Medical Sciences, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Oral Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Keng-Fu Hsu
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Graduate Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tse-Ming Hong
- Institute of Basic Medical Sciences, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Graduate Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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27
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Curry JN, Yu AS. Magnesium Handling in the Kidney. Adv Chronic Kidney Dis 2018; 25:236-243. [PMID: 29793662 DOI: 10.1053/j.ackd.2018.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/26/2017] [Accepted: 01/02/2018] [Indexed: 02/07/2023]
Abstract
Magnesium is a divalent cation that fills essential roles as regulator and cofactor in a variety of biological pathways, and maintenance of magnesium balance is vital to human health. The kidney, in concert with the intestine, has an important role in maintaining magnesium homeostasis. Although micropuncture and microperfusion studies in the mammalian nephron have shone a light on magnesium handling in the various nephron segments, much of what we know about the protein mediators of magnesium handling in the kidney have come from more recent genetic studies. In the proximal tubule and thick ascending limb, magnesium reabsorption is believed to occur primarily through the paracellular shunt pathway, which ultimately depends on the electrochemical gradient setup by active sodium reabsorption. In the distal convoluted tubule, magnesium transport is transcellular, although magnesium reabsorption also appears to be related to active sodium reabsorption in this segment. In addition, evidence suggests that magnesium transport is highly regulated, although a specific hormonal regulator of extracellular magnesium has yet to be identified.
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28
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Li H, Sun S, Chen J, Xu G, Wang H, Qian Q. Genetics of Magnesium Disorders. KIDNEY DISEASES 2017; 3:85-97. [PMID: 29344503 DOI: 10.1159/000477730] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/23/2017] [Indexed: 12/30/2022]
Abstract
Background Magnesium (Mg2+), the second most abundant cation in the cell, is woven into a multitude of cellular functions. Dysmagnesemia is associated with multiple diseases and, when severe, can be life-threatening. Summary This review discusses Mg2+ homeostasis and function with specific focus on renal Mg2+ handling. Intrarenal channels and transporters related to Mg2+ absorption are discussed. Unraveling the rare genetic diseases with manifestations of dysmagnesemia has greatly increased our understanding of the complex and intricate regulatory network in the kidney, specifically, functions of tight junction proteins including claudin-14, -16, -19, and -10; apical ion channels including: TRPM6, Kv1.1, and ROMK; small regulatory proteins including AC3 and ANK3; and basolateral proteins including EGF receptor, γ-subunit (FXYD2) of Na-K-ATPase, Kir4.1, CaSR, CNNM2, and SLC41A. Although our understanding of Mg2+ handling of the kidney has expanded considerably in the last two decades, many questions remain. Future studies are needed to elucidate a multitude of unknown aspects of Mg2+ handling in the kidney. Key Message Understanding rare and genetic diseases of Mg2+ dysregulation has expanded our knowledge and furthers the development of strategies for preventing and managing dysmagnesemia.
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Affiliation(s)
- Heng Li
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Shiren Sun
- Department of Nephrology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Jianghua Chen
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Goushuang Xu
- Department of Nephrology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Hanmin Wang
- Department of Nephrology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Qi Qian
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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29
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Viering DHHM, de Baaij JHF, Walsh SB, Kleta R, Bockenhauer D. Genetic causes of hypomagnesemia, a clinical overview. Pediatr Nephrol 2017; 32:1123-1135. [PMID: 27234911 PMCID: PMC5440500 DOI: 10.1007/s00467-016-3416-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/02/2016] [Accepted: 05/04/2016] [Indexed: 12/16/2022]
Abstract
Magnesium is essential to the proper functioning of numerous cellular processes. Magnesium ion (Mg2+) deficits, as reflected in hypomagnesemia, can cause neuromuscular irritability, seizures and cardiac arrhythmias. With normal Mg2+ intake, homeostasis is maintained primarily through the regulated reabsorption of Mg2+ by the thick ascending limb of Henle's loop and distal convoluted tubule of the kidney. Inadequate reabsorption results in renal Mg2+ wasting, as evidenced by an inappropriately high fractional Mg2+ excretion. Familial renal Mg2+ wasting is suggestive of a genetic cause, and subsequent studies in these hypomagnesemic families have revealed over a dozen genes directly or indirectly involved in Mg2+ transport. Those can be classified into four groups: hypercalciuric hypomagnesemias (encompassing mutations in CLDN16, CLDN19, CASR, CLCNKB), Gitelman-like hypomagnesemias (CLCNKB, SLC12A3, BSND, KCNJ10, FYXD2, HNF1B, PCBD1), mitochondrial hypomagnesemias (SARS2, MT-TI, Kearns-Sayre syndrome) and other hypomagnesemias (TRPM6, CNMM2, EGF, EGFR, KCNA1, FAM111A). Although identification of these genes has not yet changed treatment, which remains Mg2+ supplementation, it has contributed enormously to our understanding of Mg2+ transport and renal function. In this review, we discuss general mechanisms and symptoms of genetic causes of hypomagnesemia as well as the specific molecular mechanisms and clinical phenotypes associated with each syndrome.
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Affiliation(s)
- Daan H H M Viering
- Centre for Nephrology, University College London, London, UK
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stephen B Walsh
- Centre for Nephrology, University College London, London, UK
| | - Robert Kleta
- Centre for Nephrology, University College London, London, UK.
- Paediatric Nephrology, Great Ormond Street Hospital, London, UK.
| | - Detlef Bockenhauer
- Centre for Nephrology, University College London, London, UK
- Paediatric Nephrology, Great Ormond Street Hospital, London, UK
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Kompatscher A, de Baaij JHF, Aboudehen K, Hoefnagels APWM, Igarashi P, Bindels RJM, Veenstra GJC, Hoenderop JGJ. Loss of transcriptional activation of the potassium channel Kir5.1 by HNF1β drives autosomal dominant tubulointerstitial kidney disease. Kidney Int 2017; 92:1145-1156. [PMID: 28577853 DOI: 10.1016/j.kint.2017.03.034] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 03/08/2017] [Accepted: 03/23/2017] [Indexed: 12/20/2022]
Abstract
Hepatocyte nuclear factor 1 homeobox B (HNF1β) is an essential transcription factor for the development and functioning of the kidney. Mutations in HNF1β cause autosomal dominant tubulointerstitial kidney disease characterized by renal cysts and maturity-onset diabetes of the young (MODY). Moreover, these patients suffer from a severe electrolyte phenotype consisting of hypomagnesemia and hypokalemia. Until now, genes that are regulated by HNF1β are only partially known and do not fully explain the phenotype of the patients. Therefore, we performed chIP-seq in the immortalized mouse kidney cell line mpkDCT to identify HNF1β binding sites on a genome-wide scale. In total 7,421 HNF1β-binding sites were identified, including several genes involved in electrolyte transport and diabetes. A highly specific and conserved HNF1β site was identified in the promoter of Kcnj16 that encodes the potassium channel Kir5.1. Luciferase-promoter assays showed a 2.2-fold increase in Kcnj16 expression when HNF1β was present. Expression of the Hnf1β p.Lys156Glu mutant, previously identified in a patient with autosomal dominant tubulointerstitial kidney disease, did not activate Kcnj16 expression. Knockdown of Hnf1β in mpkDCT cells significantly reduced the appearance of Kcnj16 (Kir5.1) and Kcnj10 (Kir4.1) by 38% and 37%, respectively. These results were confirmed in a HNF1β renal knockout mouse which exhibited downregulation of Kcnj16, Kcnj10 and Slc12a3 transcripts in the kidney by 78%, 83% and 76%, respectively, compared to HNF1β wild-type mice. Thus, HNF1β is a transcriptional activator of Kcnj16. Hence, patients with HNF1β mutations may have reduced Kir5.1 activity in the kidney, resulting in hypokalemia and hypomagnesemia.
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Affiliation(s)
- Andreas Kompatscher
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Karam Aboudehen
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Anke P W M Hoefnagels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Peter Igarashi
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Gertjan J C Veenstra
- Department of Molecular Developmental Biology, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, Netherlands.
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Abstract
PURPOSE OF REVIEW Magnesium (Mg) imbalances are frequently overlooked. Hypermagnesemia usually occurs in preeclamptic women after Mg therapy or in end-stage renal disease patients, whereas hypomagnesemia is more common with a prevalence of up to 15% in the general population. Increasing evidence points toward a role for mild-to-moderate chronic hypomagnesemia in the pathogenesis of hypertension, type 2 diabetes mellitus, and metabolic syndrome. RECENT FINDINGS The kidneys are the major regulator of total body Mg homeostasis. Over the last decade, the identification of the responsible genes in rare genetic disorders has enhanced our understanding of how the kidney handles Mg. The different genetic disorders and medications contributing to abnormal Mg homeostasis are reviewed. SUMMARY As dysfunctional Mg homeostasis contributes to the development of many common human disorders, serum Mg deserves closer monitoring. Hypomagnesemic patients may be asymptomatic or may have mild symptoms. In severe hypomagnesemia, patients may present with neurological symptoms such as seizures, spasms, or cramps. Renal symptoms include nephrocalcinosis and impaired renal function. Most conditions affect tubular Mg reabsorption by disturbing the lumen-positive potential in the thick ascending limb or the negative membrane potential in the distal convoluted tubule.
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Abstract
Congenital abnormalities of the kidney and urinary tract (CAKUT) are one of the leading congenital defects to be identified on prenatal ultrasound. CAKUT represent a broad spectrum of abnormalities, from transient hydronephrosis to severe bilateral renal agenesis. CAKUT are a major contributor to chronic and end stage kidney disease (CKD/ESKD) in children. Prenatal imaging is useful to identify CAKUT, but will not detect all defects. Both genetic abnormalities and the fetal environment contribute to CAKUT. Monogenic gene mutations identified in human CAKUT have advanced our understanding of molecular mechanisms of renal development. Low nephron number and solitary kidneys are associated with increased risk of adult onset CKD and ESKD. Premature and low birth weight infants represent a high risk population for low nephron number. Additional research is needed to identify biomarkers and appropriate follow-up of premature and low birth weight infants into adulthood.
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Affiliation(s)
- Stacy Rosenblum
- Department of Pediatrics/Neonatology, Children's Hospital of Montefiore/Einstein, Bronx, NY, USA
| | - Abhijeet Pal
- Department of Pediatrics/Nephrology, Children's Hospital of Montefiore/Einstein, Bronx, NY, USA
| | - Kimberly Reidy
- Department of Pediatrics/Nephrology, Children's Hospital of Montefiore/Einstein, Bronx, NY, USA.
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Browne JA, Yang R, Eggener SE, Leir SH, Harris A. HNF1 regulates critical processes in the human epididymis epithelium. Mol Cell Endocrinol 2016; 425:94-102. [PMID: 26808453 PMCID: PMC4799753 DOI: 10.1016/j.mce.2016.01.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 12/26/2015] [Accepted: 01/20/2016] [Indexed: 01/22/2023]
Abstract
The luminal environment of the epididymis participates in sperm maturation and impacts male fertility. It is dependent on the coordinated expression of many genes encoding proteins with a role in epithelial transport. We identified cis-regulatory elements for critical genes in epididymis function, by mapping open chromatin genome-wide in human epididymis epithelial (HEE) cells. Bioinformatic predictions of transcription factors binding to the regulatory elements suggested an important role for hepatocyte nuclear factor 1 (HNF1) in the transcriptional program of these cells. Chromatin immunoprecipitation and deep sequencing (ChIP-seq) revealed HNF1 target genes in HEE cells. In parallel, the contribution of HNF1 to the transcriptome of HEE cells was determined by RNA-seq, following siRNA-mediated depletion of both HNF1α and HNF1β transcription factors. Repression of these factors caused differential expression of 1892 transcripts (902 were downregulated and 990 upregulated) in comparison to non-targeting siRNAs. Differentially expressed genes with HNF1 ChIP-seq peaks within 20 kb were subject to gene ontology process enrichment analysis. Among the most significant processes associated with down-regulated genes were epithelial transport of water, phosphate and bicarbonate, all critical processes in epididymis epithelial function. Measurements of intracellular pH (pHi) confirmed a role for HNF1 in regulating the epididymis luminal environment.
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Affiliation(s)
- James A Browne
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, USA
| | - Rui Yang
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, USA
| | - Scott E Eggener
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Shih-Hsing Leir
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, USA
| | - Ann Harris
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, USA.
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Bech AP, Wetzels JF, Bongers EMHF, Nijenhuis T. Thiazide Responsiveness Testing in Patients With Renal Magnesium Wasting and Correlation With Genetic Analysis: A Diagnostic Test Study. Am J Kidney Dis 2016; 68:168-70. [PMID: 26830254 DOI: 10.1053/j.ajkd.2015.12.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/18/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Anneke P Bech
- Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Jack F Wetzels
- Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Tom Nijenhuis
- Radboud University Medical Center, Nijmegen, the Netherlands
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35
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Uy N, Reidy K. Developmental Genetics and Congenital Anomalies of the Kidney and Urinary Tract. J Pediatr Genet 2015; 5:51-60. [PMID: 27617142 DOI: 10.1055/s-0035-1558423] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/10/2015] [Indexed: 02/06/2023]
Abstract
Congenital anomalies of the kidney and urinary tract (CAKUT) are common birth defects and the leading cause of end-stage renal disease in children. There is a wide spectrum of renal abnormalities, from mild hydronephrosis to more severe cases, such as bilateral renal dysplasia. The etiology of the majority of cases of CAKUT remains unknown, but there is increasing evidence that genomic imbalance contributes to the pathogenesis of CAKUT. Advances in human and mouse genetics have contributed to increased understanding of the pathophysiology of CAKUT. Mutations in genes involved in both transcription factors and signal transduction pathways involved in renal development are associated with CAKUT. Large cohort studies suggest that copy number variants, genomic, or de novo mutations may explain up to one-third of all cases of CAKUT. One of the major challenges to the use of genetic information in the clinical setting remains the lack of strict genotype-phenotype correlation. However, identifying genetic causes of CAKUT may lead to improved diagnosis of extrarenal complications. With the advent of decreasing costs for whole genome and exome sequencing, future studies focused on genotype-phenotype correlations, gene modifiers, and animal models of gene mutations will be needed to translate genetic advances into improved clinical care.
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Affiliation(s)
- Natalie Uy
- Department of Pediatrics/Nephrology, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Kimberly Reidy
- Department of Pediatrics/Nephrology, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York, United States
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36
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Verhave JC, Bech AP, Wetzels JFM, Nijenhuis T. Hepatocyte Nuclear Factor 1β-Associated Kidney Disease: More than Renal Cysts and Diabetes. J Am Soc Nephrol 2015; 27:345-53. [PMID: 26319241 DOI: 10.1681/asn.2015050544] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Hepatocyte nuclear factor 1β (HNF1β)-associated disease is a recently recognized clinical entity with a variable multisystem phenotype. Early reports described an association between HNF1B mutations and maturity-onset diabetes of the young. These patients often presented with renal cysts and renal function decline that preceded the diabetes, hence it was initially referred to as renal cysts and diabetes syndrome. However, it is now evident that many more symptoms occur, and diabetes and renal cysts are not always present. The multisystem phenotype is probably attributable to functional promiscuity of the HNF1β transcription factor, involved in the development of the kidney, urogenital tract, pancreas, liver, brain, and parathyroid gland. Nephrologists might diagnose HNF1β-associated kidney disease in patients referred with a suspected diagnosis of autosomal dominant polycystic kidney disease, medullary cystic kidney disease, diabetic nephropathy, or CKD of unknown cause. Associated renal or extrarenal symptoms should alert the nephrologist to HNF1β-associated kidney disease. A considerable proportion of these patients display hypomagnesemia, which sometimes mimics Gitelman syndrome. Other signs include early onset diabetes, gout and hyperparathyroidism, elevated liver enzymes, and congenital anomalies of the urogenital tract. Because many cases of this disease are probably undiagnosed, this review emphasizes the clinical manifestations of HNF1β-associated disease for the nephrologist.
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Affiliation(s)
- Jacobien C Verhave
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Anneke P Bech
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jack F M Wetzels
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tom Nijenhuis
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
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37
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de Baaij JHF, Hoenderop JGJ, Bindels RJM. Regulation of magnesium balance: lessons learned from human genetic disease. Clin Kidney J 2015; 5:i15-i24. [PMID: 26069817 PMCID: PMC4455826 DOI: 10.1093/ndtplus/sfr164] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Magnesium (Mg(2+)) is the fourth most abundant cation in the body. Thus, magnesium homeostasis needs to be tightly regulated, and this is facilitated by intestinal absorption and renal excretion. Magnesium absorption is dependent on two concomitant pathways found in both in the intestine and the kidneys: passive paracellular transport via claudins facilitates bulk magnesium absorption, whereas active transcellular pathways mediate the fine-tuning of magnesium absorption. The identification of genes responsible for diseases associated with hypomagnesaemia resulted in the discovery of several magnesiotropic proteins. Claudins 16 and 19 form the tight junction pore necessary for mass magnesium transport. However, most of the causes of genetic hypomagnesaemia can be tracked down to transcellular magnesium transport in the distal convoluted tubule. Within the distal convoluted tubule, magnesium reabsorption is a tightly regulated process that determines the final urine magnesium concentration. Therefore, insufficient magnesium transport in the distal convoluted tubule owing to mutated magnesiotropic proteins inevitably leads to magnesium loss, which cannot be compensated for in downstream tubule segments. Better understanding of the molecular mechanism regulating magnesium reabsorption will give new opportunities for better therapies, perhaps including therapies for patients with chronic renal failure.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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38
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Singh V, Singla SK, Jha V, Puri V, Puri S. Hepatocyte nuclear factor-1β: A regulator of kidney development and cystogenesis. Indian J Nephrol 2015; 25:70-6. [PMID: 25838642 PMCID: PMC4379628 DOI: 10.4103/0971-4065.139492] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The understanding of the genomics of the renal tissue has gathered a considerable interest and is making rapid progress. The molecular mechanisms as well as the precise function of the associated molecular components toward renal pathophysiology have recently been realized. For the cystic kidney disease, the regulation of gene expression affecting epithelial cells proliferation, apoptosis as well as process of differentiation/de-differentiation represent key molecular targets. For the cystic disorders, molecular targets have been identified, which besides lending heterogeneity to cysts may also provide tools to unravel their functional importance to understand the renal tissue homeostasis. This review focuses on providing comprehensive information about the transcriptional regulatory role of hepatocyte nuclear factor-1β, a homeoprotein, as well as its interacting partners in renal tissue development and pathophysiology.
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Affiliation(s)
- V Singh
- Department of Biochemistry, Panjab University, Chandigarh, India
| | - S K Singla
- Department of Biochemistry, Panjab University, Chandigarh, India
| | - V Jha
- Department of Nephrology, PGIMER, Chandigarh, India
| | - V Puri
- Centre for Systems Biology and Bioinformatics, Under University Institute of Emerging Areas in Science and Technology, Panjab University, Chandigarh, India
| | - S Puri
- Biotechnology Branch, University Institute of Engineering and Technology, Chandigarh, India ; Centre for Stem Cell and Issue Engineering, University Institute of Emerging Areas in Science and Technology, Panjab University, Chandigarh, India
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39
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de Baaij JHF, Dorresteijn EM, Hennekam EAM, Kamsteeg EJ, Meijer R, Dahan K, Muller M, van den Dorpel MA, Bindels RJM, Hoenderop JGJ, Devuyst O, Knoers NVAM. Recurrent FXYD2 p.Gly41Arg mutation in patients with isolated dominant hypomagnesaemia. Nephrol Dial Transplant 2015; 30:952-7. [PMID: 25765846 DOI: 10.1093/ndt/gfv014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/15/2014] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Magnesium (Mg(2+)) is an essential ion for cell growth, neuroplasticity and muscle contraction. Blood Mg(2+) levels <0.7 mmol/L may cause a heterogeneous clinical phenotype, including muscle cramps and epilepsy and disturbances in K(+) and Ca(2+) homeostasis. Over the last decade, the genetic origin of several familial forms of hypomagnesaemia has been found. In 2000, mutations in FXYD2, encoding the γ-subunit of the Na(+)-K(+)-ATPase, were identified to cause isolated dominant hypomagnesaemia (IDH) in a large Dutch family suffering from hypomagnesaemia, hypocalciuria and chondrocalcinosis. However, no additional patients have been identified since then. METHODS Here, two families with hypomagnesaemia and hypocalciuria were screened for mutations in the FXYD2 gene. Moreover, the patients were clinically and genetically characterized. RESULTS We report a p.Gly41Arg FXYD2 mutation in two families with hypomagnesaemia and hypocalciuria. Interestingly, this is the same mutation as was described in the original study. As in the initial family, several patients suffered from muscle cramps, chondrocalcinosis and epilepsy. Haplotype analysis revealed an overlapping haplotype in all families, suggesting a founder effect. CONCLUSIONS The recurrent p.Gly41Arg FXYD2 mutation in two new families with IDH confirms that FXYD2 mutation causes hypomagnesaemia. Until now, no other FXYD2 mutations have been reported which could indicate that other FXYD2 mutations will not cause hypomagnesaemia or are embryonically lethal.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Eiske M Dorresteijn
- Pediatric Nephrology, Erasmus MC, Sophia Childrens Hospital, Rotterdam, The Netherlands
| | - Eric A M Hennekam
- Department of Medical Genetics, University Medical Centre Utrecht, Utrecht 3508 AB, The Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rowdy Meijer
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Karin Dahan
- Institut de Génétique et de Pathologie, IPG, Gosselies, Belgium
| | | | | | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Olivier Devuyst
- Institute of Physiology, ZIHP, University of Zurich, Zürich, Switzerland
| | - Nine V A M Knoers
- Department of Medical Genetics, University Medical Centre Utrecht, Utrecht 3508 AB, The Netherlands
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40
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de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev 2015; 95:1-46. [PMID: 25540137 DOI: 10.1152/physrev.00012.2014] [Citation(s) in RCA: 866] [Impact Index Per Article: 96.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Clissold RL, Hamilton AJ, Hattersley AT, Ellard S, Bingham C. HNF1B-associated renal and extra-renal disease—an expanding clinical spectrum. Nat Rev Nephrol 2014; 11:102-12. [DOI: 10.1038/nrneph.2014.232] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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42
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Raaijmakers A, Corveleyn A, Devriendt K, van Tienoven TP, Allegaert K, Van Dyck M, van den Heuvel L, Kuypers D, Claes K, Mekahli D, Levtchenko E. Criteria for HNF1B analysis in patients with congenital abnormalities of kidney and urinary tract. Nephrol Dial Transplant 2014; 30:835-42. [PMID: 25500806 DOI: 10.1093/ndt/gfu370] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/04/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Congenital anomalies of kidneys and urinary tract (CAKUT) are the most predominant developmental disorders comprising ∼20-30% of all anomalies identified in the prenatal period. Mutations in hepatocyte nuclear factor 1-beta (HNF-1β) involved in the development of kidneys, liver, pancreas and urogenital tract are currently the most frequent monogenetic cause of CAKUT found in 10-30% of patients depending on screening policy and study design. We aimed to validate criteria for analysis of HNF1B in a prospective cohort of paediatric and adult CAKUT patients. METHODS We included CAKUT patients diagnosed in our paediatric and adult nephrology departments from January 2010 until April 2013 based on predefined screening criteria. Subjects presenting with at least one major renal criterion or one minor renal criterion combined with one or more extra-renal criteria in the personal history or a familial history of renal or extra-renal manifestations were considered eligible. RESULTS We prospectively screened 205 patients and detected HNF1B mutations in 10% [n = 20, 12 children, median age 4.2 (range 0-13.1) years and 8 adults, median age 34.8 (range 16.6-62) years]. We observed that bilateral renal anomaly, renal cysts from unknown origin, a combination of two major renal anomalies and hypomagnesaemia were predictive for finding HNF1B mutations (P < 0.001; P < 0.001; P = 0.004; P = 0.008, respectively). CONCLUSIONS We demonstrated that HNF1B mutations are responsible for ∼10% of CAKUT cases, both in children and in adults. Based on our results we propose adapted criteria for HNF1B analysis to reduce the screening costs without missing affected patients. These criteria should be reaffirmed in a larger validation cohort.
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Affiliation(s)
| | - Anniek Corveleyn
- Department of Human Genetics, UZ Leuven/KU Leuven, Leuven, Belgium
| | - Koen Devriendt
- Department of Human Genetics, UZ Leuven/KU Leuven, Leuven, Belgium
| | | | | | - Mieke Van Dyck
- Department of Pediatric Nephrology, UZ Leuven, Leuven, Belgium
| | | | - Dirk Kuypers
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | | | - Djalila Mekahli
- Department of Pediatric Nephrology, UZ Leuven, Leuven, Belgium
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Pham PCT, Pham PAT, Pham SV, Pham PTT, Pham PMT, Pham PTT. Hypomagnesemia: a clinical perspective. Int J Nephrol Renovasc Dis 2014; 7:219-30. [PMID: 24966690 PMCID: PMC4062555 DOI: 10.2147/ijnrd.s42054] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Although magnesium is involved in a wide spectrum of vital functions in normal human physiology, the significance of hypomagnesemia and necessity for its treatment are under-recognized and underappreciated in clinical practice. In the current review, we first present an overview of the clinical significance of hypomagnesemia and normal magnesium metabolism, with a focus on renal magnesium handling. Subsequently, we review the literature for both congenital and acquired hypomagnesemic conditions that affect the various steps in normal magnesium metabolism. Finally, we present an approach to the routine evaluation and suggested management of hypomagnesemia.
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Affiliation(s)
| | - Phuong-Anh T Pham
- Veterans Administration Central California Health Care System, Fresno, CA, USA
| | - Son V Pham
- South Texas Veterans Health Care System and University of Texas Health Science Center, San Antonio, TX, USA
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44
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Naylor RW, Davidson AJ. Hnf1beta and nephron segmentation. Pediatr Nephrol 2014; 29:659-64. [PMID: 24190171 PMCID: PMC3944118 DOI: 10.1007/s00467-013-2662-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/03/2013] [Accepted: 10/09/2013] [Indexed: 01/03/2023]
Abstract
The nephron is the functional unit that executes the homeostatic roles of the kidney in vertebrates. Critical to this function is the physical arrangement of the glomerular blood filter attached to a tubular epithelium that is subdivided into specialized proximal and distal segments. During embryogenesis, nephron progenitors undergo a mesenchymal-epithelial transition (MET) and adopt different segment-specific cell fates along the proximo-distal axis of the nephron. The molecular basis of how these segments arise remains largely unknown. Recent studies using the zebrafish have identified the Hnf1beta transcription factor (Hnf1b) as a major regulator of tubular segmentation. In Hnf1b-deficient zebrafish embryos, nephron progenitors fail to adopt the proximo-distal segmentation pattern of the nephron, yet still undergo MET. This observation suggests that the functional segmentation of renal tubular epithelial cells is independent of pathways that induce their epithelialization. Here we review this new role of Hnf1b for nephron segmentation during zebrafish and mouse kidney development.
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de Baaij JHF, Groot Koerkamp MJ, Lavrijsen M, van Zeeland F, Meijer H, Holstege FCP, Bindels RJM, Hoenderop JGJ. Elucidation of the distal convoluted tubule transcriptome identifies new candidate genes involved in renal Mg2+ handling. Am J Physiol Renal Physiol 2013; 305:F1563-73. [DOI: 10.1152/ajprenal.00322.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The kidney plays a key role in the maintenance of Mg2+ homeostasis. Specifically, the distal convoluted tubule (DCT) is instrumental in the fine-tuning of renal Mg2+ handling. In recent years, hereditary Mg2+ transport disorders have helped to identify important players in DCT Mg2+ homeostasis. Nevertheless, several proteins involved in DCT-mediated Mg2+ reabsorption remain to be discovered, and a full expression profile of this complex nephron segment may facilitate the discovery of new Mg2+-related genes. Here, we report Mg2+-sensitive expression of the DCT transcriptome. To this end, transgenic mice expressing enhanced green fluorescent protein under a DCT-specific parvalbumin promoter were subjected to Mg2+-deficient or Mg2+-enriched diets. Subsequently, the Complex Object Parametric Analyzer and Sorter allowed, for the first time, isolation of enhanced green fluorescent protein-positive DCT cells. RNA extracts thereof were analyzed by DNA microarrays comparing high versus low Mg2+ to identify Mg2+ regulatory genes. Based on statistical significance and a fold change of at least 2, 46 genes showed differential expression. Several known magnesiotropic genes, such as transient receptor potential cation channel, subfamily M, member 6 ( Trpm6), and Parvalbumin, were upregulated under low dietary Mg2+. Moreover, new genes were identified that are potentially involved in renal Mg2+ handling. To confirm that the selected candidate genes were regulated by dietary Mg2+ availability, the expression levels of solute carrier family 41, member 3 ( Slc41a3), pterin-4 α-carbinolamine dehydratase/dimerization cofactor of hepatocyte nuclear factor-1α ( Pcbd1), TBC1 domain family, member 4 ( Tbc1d4), and uromodulin ( Umod) were determined by RT-PCR analysis. Indeed, all four genes show significant upregulation in the DCT of mice fed a Mg2+-deficient diet. By elucidating the Mg2+-sensitive DCT transcriptome, new candidate genes in renal Mg2+ handling have been identified.
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Affiliation(s)
- Jeroen H. F. de Baaij
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and
| | | | - Marla Lavrijsen
- Molecular Cancer Research, UMC Utrecht, Utrecht, The Netherlands
| | - Femke van Zeeland
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and
| | - Hans Meijer
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and
| | | | - René J. M. Bindels
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and
| | - Joost G. J. Hoenderop
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and
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Ferrè S, de Baaij JHF, Ferreira P, Germann R, de Klerk JBC, Lavrijsen M, van Zeeland F, Venselaar H, Kluijtmans LAJ, Hoenderop JGJ, Bindels RJM. Mutations in PCBD1 cause hypomagnesemia and renal magnesium wasting. J Am Soc Nephrol 2013; 25:574-86. [PMID: 24204001 DOI: 10.1681/asn.2013040337] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Mutations in PCBD1 are causative for transient neonatal hyperphenylalaninemia and primapterinuria (HPABH4D). Until now, HPABH4D has been regarded as a transient and benign neonatal syndrome without complications in adulthood. In our study of three adult patients with homozygous mutations in the PCBD1 gene, two patients were diagnosed with hypomagnesemia and renal Mg(2+) loss, and two patients developed diabetes with characteristics of maturity onset diabetes of the young (MODY), regardless of serum Mg(2+) levels. Our results suggest that these clinical findings are related to the function of PCBD1 as a dimerization cofactor for the transcription factor HNF1B. Mutations in the HNF1B gene have been shown to cause renal malformations, hypomagnesemia, and MODY. Gene expression studies combined with immunohistochemical analysis in the kidney showed that Pcbd1 is expressed in the distal convoluted tubule (DCT), where Pcbd1 transcript levels are upregulated by a low Mg(2+)-containing diet. Overexpression in a human kidney cell line showed that wild-type PCBD1 binds HNF1B to costimulate the FXYD2 promoter, the activity of which is instrumental in Mg(2+) reabsorption in the DCT. Of seven PCBD1 mutations previously reported in HPABH4D patients, five mutations caused proteolytic instability, leading to reduced FXYD2 promoter activity. Furthermore, cytosolic localization of PCBD1 increased when coexpressed with HNF1B mutants. Overall, our findings establish PCBD1 as a coactivator of the HNF1B-mediated transcription necessary for fine tuning FXYD2 transcription in the DCT and suggest that patients with HPABH4D should be monitored for previously unrecognized late complications, such as hypomagnesemia and MODY diabetes.
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Affiliation(s)
- Silvia Ferrè
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences
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van Angelen AA, San-Cristobal P, Pulskens WP, Hoenderop JG, Bindels RJ. The impact of dietary magnesium restriction on magnesiotropic and calciotropic genes. Nephrol Dial Transplant 2013; 28:2983-93. [DOI: 10.1093/ndt/gft358] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Uekuri C, Shigetomi H, Ono S, Sasaki Y, Matsuura M, Kobayashi H. Toward an understanding of the pathophysiology of clear cell carcinoma of the ovary (Review). Oncol Lett 2013; 6:1163-1173. [PMID: 24179489 PMCID: PMC3813717 DOI: 10.3892/ol.2013.1550] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 07/29/2013] [Indexed: 12/12/2022] Open
Abstract
Endometriosis-associated ovarian cancers demonstrate substantial morphological and genetic diversity. The transcription factor, hepatocyte nuclear factor (HNF)-1β, may be one of several key genes involved in the identity of ovarian clear cell carcinoma (CCC). The present study reviews a considerably expanded set of HNF-1β-associated genes and proteins that determine the pathophysiology of CCC. The current literature was reviewed by searching MEDLINE/PubMed. Functional interpretations of gene expression profiling in CCC are provided. Several important CCC-related genes overlap with those known to be regulated by the upregulation of HNF-1β expression, along with a lack of estrogen receptor (ER) expression. Furthermore, the genetic expression pattern in CCC resembles that of the Arias-Stella reaction, decidualization and placentation. HNF-1β regulates a subset of progesterone target genes. HNF-1β may also act as a modulator of female reproduction, playing a role in endometrial regeneration, differentiation, decidualization, glycogen synthesis, detoxification, cell cycle regulation, implantation, uterine receptivity and a successful pregnancy. In conclusion, the present study focused on reviewing the aberrant expression of CCC-specific genes and provided an update on the pathological implications and molecular functions of well-characterized CCC-specific genes.
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Affiliation(s)
- Chiharu Uekuri
- Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Nara 634-8522, Japan
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Naylor RW, Przepiorski A, Ren Q, Yu J, Davidson AJ. HNF1β is essential for nephron segmentation during nephrogenesis. J Am Soc Nephrol 2012; 24:77-87. [PMID: 23160512 DOI: 10.1681/asn.2012070756] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Nephrons comprise a blood filter and an epithelial tubule that is subdivided into proximal and distal segments, but what directs this patterning during kidney organogenesis is not well understood. Using zebrafish, we found that the HNF1β paralogues hnf1ba and hnf1bb, which encode homeodomain transcription factors, are essential for normal segmentation of nephrons. Embryos deficient in hnf1ba and hnf1bb did not express proximal and distal segment markers, yet still developed an epithelial tubule. Initiating hnf1ba/b expression required Pax2a and Pax8, but hnf1ba/b-deficient embryos did not exhibit the expected downregulation of pax2a and pax8 at later stages of development, suggesting complex regulatory loops involving these molecules. Embryos deficient in hnf1ba/b also did not express the irx3b transcription factor, which is responsible for differentiation of the first distal tubule segment. Reciprocally, embryos deficient in irx3b exhibited downregulation of hnf1ba/b transcripts in the distal early segment, suggesting a segment-specific regulatory circuit. Deficiency of hnf1ba/b also led to ectopic expansion of podocytes into the proximal tubule domain. Epistasis experiments showed that the formation of podocytes required wt1a, which encodes the Wilms' tumor suppressor-1 transcription factor, and rbpj, which encodes a mediator of canonical Notch signaling, downstream or parallel to hnf1ba/b. Taken together, these results suggest that Hnf1β factors are essential for normal segmentation of nephrons during kidney organogenesis.
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Affiliation(s)
- Richard W Naylor
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland 1142, New Zealand
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