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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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Hoogstraten CA, Hoenderop JG, de Baaij JHF. Mitochondrial Dysfunction in Kidney Tubulopathies. Annu Rev Physiol 2024; 86:379-403. [PMID: 38012047 DOI: 10.1146/annurev-physiol-042222-025000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Mitochondria play a key role in kidney physiology and pathology. They produce ATP to fuel energy-demanding water and solute reabsorption processes along the nephron. Moreover, mitochondria contribute to cellular health by the regulation of autophagy, (oxidative) stress responses, and apoptosis. Mitochondrial abundance is particularly high in cortical segments, including proximal and distal convoluted tubules. Dysfunction of the mitochondria has been described for tubulopathies such as Fanconi, Gitelman, and Bartter-like syndromes and renal tubular acidosis. In addition, mitochondrial cytopathies often affect renal (tubular) tissues, such as in Kearns-Sayre and Leigh syndromes. Nevertheless, the mechanisms by which mitochondrial dysfunction results in renal tubular diseases are only scarcely being explored. This review provides an overview of mitochondrial dysfunction in the development and progression of kidney tubulopathies. Furthermore, it emphasizes the need for further mechanistic investigations to identify links between mitochondrial function and renal electrolyte reabsorption.
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Affiliation(s)
- Charlotte A Hoogstraten
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands;
| | - Joost G Hoenderop
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands;
| | - Jeroen H F de Baaij
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands;
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Khan R, Chaturvedi P, Sahu P, Ludhiadch A, Singh P, Singh G, Munshi A. Role of Potassium Ion Channels in Epilepsy: Focus on Current Therapeutic Strategies. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:67-87. [PMID: 36578258 DOI: 10.2174/1871527322666221227112621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 11/10/2022] [Accepted: 11/12/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Epilepsy is one of the prevalent neurological disorders characterized by disrupted synchronization between inhibitory and excitatory neurons. Disturbed membrane potential due to abnormal regulation of neurotransmitters and ion transport across the neural cell membrane significantly contributes to the pathophysiology of epilepsy. Potassium ion channels (KCN) regulate the resting membrane potential and are involved in neuronal excitability. Genetic alterations in the potassium ion channels (KCN) have been reported to result in the enhancement of the release of neurotransmitters, the excitability of neurons, and abnormal rapid firing rate, which lead to epileptic phenotypes, making these ion channels a potential therapeutic target for epilepsy. The aim of this study is to explore the variations reported in different classes of potassium ion channels (KCN) in epilepsy patients, their functional evaluation, and therapeutic strategies to treat epilepsy targeting KCN. METHODOLOGY A review of all the relevant literature was carried out to compile this article. RESULTS A large number of variations have been reported in different genes encoding various classes of KCN. These genetic alterations in KCN have been shown to be responsible for disrupted firing properties of neurons. Antiepileptic drugs (AEDs) are the main therapeutic strategy to treat epilepsy. Some patients do not respond favorably to the AEDs treatment, resulting in pharmacoresistant epilepsy. CONCLUSION Further to address the challenges faced in treating epilepsy, recent approaches like optogenetics, chemogenetics, and genome editing, such as clustered regularly interspaced short palindromic repeats (CRISPR), are emerging as target-specific therapeutic strategies.
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Affiliation(s)
- Rahul Khan
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Pragya Chaturvedi
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Prachi Sahu
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Abhilash Ludhiadch
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Paramdeep Singh
- Department of Radiology, All India Institute of Medical Sciences, Bathinda, Punjab, 151001 India
| | - Gagandeep Singh
- Department of Neurology, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
| | - Anjana Munshi
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
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Garcia-Nieto VM, Claverie-Martin F, Moraleda-Mesa T, Perdomo-Ramírez A, Fraga-Rodríguez GM, Luis-Yanes MI, Ramos-Trujillo E. Renal diseases that course with hypomagnesemia. Comments on a new hereditary hypomagnesemic tubulopathy. Nefrologia 2024; 44:23-31. [PMID: 38350738 DOI: 10.1016/j.nefroe.2024.02.003] [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: 01/26/2023] [Accepted: 02/15/2023] [Indexed: 02/15/2024] Open
Abstract
Renal diseases associated with hypomagnesemia are a complex and diverse group of tubulopathies caused by mutations in genes encoding proteins that are expressed in the thick ascending limb of the loop of Henle and in the distal convoluted tubule. In this paper, we review the initial description, the clinical expressiveness and etiology of four of the first hypomagnesemic tubulopathies described: type 3 Bartter and Gitelman diseases, Autosomal recessive hypomagnesemia with secondary hypocalcemia and Familial hypomagnesemia with hypercalciuria and nephrocalcinosis. The basic biochemical patterns observed in renal tubular hypomagnesemias and the modalities of transport and interaction that occur between the transporters involved in the reabsorption of magnesium in the distal convoluted tubule are described below. Finally, the recent report of a new renal disease with hypomagnesemia, type 2 hypomagnesemia with secondary hypocalcemia caused by reduced TRPM7 channel activity is described.
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Affiliation(s)
- Víctor M Garcia-Nieto
- Unidad de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain.
| | - Félix Claverie-Martin
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Teresa Moraleda-Mesa
- Unidad de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Ana Perdomo-Ramírez
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Gloria Mª Fraga-Rodríguez
- Nefrologia Pediàtrica, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - María Isabel Luis-Yanes
- Unidad de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Elena Ramos-Trujillo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain; Departamento de Medicina Física y Farmacología, Facultad de Medicina, Universidad de la Laguna, Santa Cruz de Tenerife, Spain
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Kurkowiak M, Fletcher S, Daniels A, Mozolewski P, Silvestris DA, Król E, Marek-Trzonkowska N, Hupp T, Tait-Burkard C. Differential RNA editing landscapes in host cell versus the SARS-CoV-2 genome. iScience 2023; 26:108031. [PMID: 37876814 PMCID: PMC10590966 DOI: 10.1016/j.isci.2023.108031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 08/09/2023] [Accepted: 09/21/2023] [Indexed: 10/26/2023] Open
Abstract
The SARS-CoV-2 pandemic was defined by the emergence of new variants formed through virus mutation originating from random errors not corrected by viral proofreading and/or the host antiviral response introducing mutations into the viral genome. While sequencing information hints at cellular RNA editing pathways playing a role in viral evolution, here, we use an in vitro human cell infection model to assess RNA mutation types in two SARS-CoV-2 strains representing the original and the alpha variants. The variants showed both different cellular responses and mutation patterns with alpha showing higher mutation frequency with most substitutions observed being C-U, indicating an important role for apolipoprotein B mRNA editing catalytic polypeptide-like editing. Knockdown of select APOBEC3s through RNAi increased virus production in the original virus, but not in alpha. Overall, these data suggest a deaminase-independent anti-viral function of APOBECs in SARS-CoV-2 while the C-U editing itself might function to enhance genetic diversity enabling evolutionary adaptation.
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Affiliation(s)
- Małgorzata Kurkowiak
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland
| | - Sarah Fletcher
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Alison Daniels
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
- Infection Medicine, University of Edinburgh, Little France Crescent, UK
| | - Paweł Mozolewski
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland
| | | | - Ewelina Król
- Department of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Natalia Marek-Trzonkowska
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland
- Laboratory of Immunoregulation and Cellular Therapies, Department of Family Medicine Medical University of Gdańsk, Gdańsk, Poland
| | - Ted Hupp
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland
- Cell Signalling Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Christine Tait-Burkard
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
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Chen J, Fu Y, Sun Y, Zhou X, Wang Q, Li C, Yuan H. Novel KCNJ16 variants identified in a Chinese patient with hypokalemic metabolic acidosis. Mol Genet Genomic Med 2023; 11:e2238. [PMID: 37466410 PMCID: PMC10655507 DOI: 10.1002/mgg3.2238] [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: 03/11/2023] [Revised: 07/02/2023] [Accepted: 07/05/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND Biallelic pathogenic variants in the KCNJ16 gene result in hypokalemic tubulopathy and deafness (HKTD) (MIM #619406), which is a rare autosomal recessive disease characterized by hypokalemic tubulopathy with renal salt wasting, disturbed acid-base homeostasis, and sensorineural deafness. Currently, nine individuals with HKTD have been reported, and seven pathogenic variants in KCNJ16 have been revealed. METHODS A 5-year-6-month-old Chinese female patient displayed hypokalemic metabolic acidosis, salt wasting, renin-angiotensin-aldosterone system (RAAS) activation, arrhythmia, myocardial damage, cardiogenic shock and secondary diffuse brain oedema. Trio-based whole-exome sequencing (WES) was applied to detect the genetic cause. RESULTS Novel compound heterozygous variants, c.190A>C (p.Thr64Pro) and c.628C>G (p.His210Asp), in KCNJ16 were detected in the patient, and these variants were inherited from the patient's mother and father, respectively. Then, we systematically reviewed the available clinical manifestations of individuals with HKTD. We found that HKTD patients are at risk of cardiogenic shock and secondary diffuse brain oedema, which urges clinicians to make early diagnoses with prompt treatments. CONCLUSION These findings expand the variant spectrum of KCNJ16, enrich the clinical characteristics of HKTD, and provide a solid base for the genetic counseling, diagnosis and treatment of this condition.
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Affiliation(s)
- Jianxiong Chen
- Dongguan Maternal and Child Health Care HospitalDongguanChina
- Key Laboratory for Precision Diagnosis and Treatment of Severe Infectious Diseases in ChildrenDongguanChina
| | - Youqing Fu
- Dongguan Maternal and Child Health Care HospitalDongguanChina
| | - Yan Sun
- Dongguan Maternal and Child Health Care HospitalDongguanChina
| | - Xinlong Zhou
- Dongguan Maternal and Child Health Care HospitalDongguanChina
- Key Laboratory for Precision Diagnosis and Treatment of Severe Infectious Diseases in ChildrenDongguanChina
| | - Qingming Wang
- Dongguan Maternal and Child Health Care HospitalDongguanChina
- Department of Medical GeneticsDongguan Maternal and Child Health Care HospitalDongguanChina
| | - Cong Li
- Dongguan Maternal and Child Health Care HospitalDongguanChina
| | - Haiming Yuan
- Dongguan Maternal and Child Health Care HospitalDongguanChina
- Department of Medical GeneticsDongguan Maternal and Child Health Care HospitalDongguanChina
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Manis AD, Cook-Snyder DR, Duffy E, Osmani WA, Eilbes M, Dillard M, Palygin O, Staruschenko A, Hodges MR. Repeated seizures lead to progressive ventilatory dysfunction in SS Kcnj16-/- rats. J Appl Physiol (1985) 2023; 135:872-885. [PMID: 37535709 PMCID: PMC10642517 DOI: 10.1152/japplphysiol.00072.2023] [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: 02/06/2023] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 08/05/2023] Open
Abstract
Patients with uncontrolled epilepsy experience repeated seizures putting them at increased risk for sudden unexpected death in epilepsy (SUDEP). Data from human patients have led to the hypothesis that SUDEP results from severe cardiorespiratory suppression after a seizure, which may involve pathological deficiencies in the brainstem serotonin (5-HT) system. Rats with a genomic Kcnj16 mutation (SSKcnj16-/- rats) are susceptible to sound-induced generalized tonic-clonic seizures (GTCS) which, when repeated once daily for up to 10 days (10-day seizure protocol), increased mortality, particularly in male rats. Here, we test the hypothesis that repeated seizures across the 10-day protocol will cause a progressive ventilatory dysfunction due to time-dependent 5-HT deficiency. Initial severe seizures led to ictal and postictal apneas and transient decreases in breathing frequency, ventilatory drive, breath-to-breath variability, and brief hypoventilation. These seizure-induced effects on ventilation were exacerbated with increasing seizures and ventilatory chemoreflexes became further impaired after repeated seizures. Tissue analyses of key brainstem regions controlling breathing showed time-dependent 5-HT system suppression and increased immunoreactivity for IBA-1 (microglial marker) without changes in overall cell counts at 3, 7, and 10 days of seizures. Fluoxetine treatment in SSKcnj16-/- rats prevented repeated seizure-induced progressive respiratory suppression but failed to prevent seizure-related mortality. We conclude that repeated seizures cause a progressive compromise of ventilatory control in the immediate postictal period largely mediated by serotonin system suppression in brainstem regions of respiratory control. However, other unknown factors contribute to overall survival following repeated seizures in this model.NEW & NOTEWORTHY This study demonstrated that repeated seizures in a novel rat model (SSKcnj16-/- rats) caused a progressively greater ventilatory dysfunction in the immediate postictal period associated with brainstem serotonin (5-HT) suppression. Augmenting brain 5-HT with a selective serotonin reuptake inhibitor prevented the progressive ventilatory dysfunction induced by repeated seizures but failed to prevent seizure-related mortality, suggesting that repeated seizures may lead to cardiorespiratory suppression and failure through multiple mechanisms.
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Affiliation(s)
- Anna D Manis
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Denise R Cook-Snyder
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Erin Duffy
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Wasif A Osmani
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Melissa Eilbes
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Matthew Dillard
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Molecular Pharmacology & Physiology, University of South Florida, Tampa, Florida, United States
- James A. Haley Veterans' Hospital, Tampa, Florida, United States
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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Gamba G. Thirty years of the NaCl cotransporter: from cloning to physiology and structure. Am J Physiol Renal Physiol 2023; 325:F479-F490. [PMID: 37560773 PMCID: PMC10639029 DOI: 10.1152/ajprenal.00114.2023] [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: 05/02/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/11/2023] Open
Abstract
The primary structure of the thiazide-sensitive NaCl cotransporter (NCC) was resolved 30 years ago by the molecular identification of the cDNA encoding this cotransporter, from the winter's flounder urinary bladder, following a functional expression strategy. This review outlines some aspects of how the knowledge about thiazide diuretics and NCC evolved, the history of the cloning process, and the expansion of the SLC12 family of electroneutral cotransporters. The diseases associated with activation or inactivation of NCC are discussed, as well as the molecular model by which the activity of NCC is regulated. The controversies in the field are discussed as well as recent publication of the three-dimensional model of NCC obtained by cryo-electron microscopy, revealing not only the amino acid residues critical for Na+ and Cl- translocation but also the residues critical for polythiazide binding to the transporter, opening the possibility for a new era in thiazide diuretic therapy.
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Affiliation(s)
- Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Lee HK, Jung NH, Lee DE, Lee H, Yang J, Kim YS, Han SS, Han N, Kim IW, Oh JM. Discovery of Biomarkers Related to Interstitial Fibrosis and Tubular Atrophy among Kidney Transplant Recipients by mRNA-Sequencing. J Pers Med 2023; 13:1242. [PMID: 37623492 PMCID: PMC10455123 DOI: 10.3390/jpm13081242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/28/2023] [Accepted: 08/08/2023] [Indexed: 08/26/2023] Open
Abstract
Interstitial fibrosis and tubular atrophy (IF/TA) after kidney transplantation causes a chronic deterioration of graft function. IF/TA can be diagnosed by means of a graft biopsy, which is a necessity as non-invasive diagnostic methods are unavailable. In this study, we identified IF/TA-related differentially expressed genes (DEGs) through next-generation sequencing using peripheral blood mononuclear cells. Blood samples from kidney transplant recipients undergoing standard immunosuppressive therapy (tacrolimus/mycophenolate mofetil or mycophenolate sodium/steroid) and diagnosed as IF/TA (n = 41) or normal (controls; n = 41) at their one-year protocol biopsy were recruited between January of 2020 and August of 2020. DEGs were derived through mRNA sequencing and validated by means of a quantitative real-time polymerase chain reaction. We identified 34 DEGs related to IF/TA. ADAMTS2, PLIN5, CLDN9, and KCNJ15 demonstrated a log2(fold change) of >1.5 and an area under the receiver operating characteristic curve (AUC) value of >0.6, with ADAMTS2 showing the largest AUC value and expression levels, which were 3.5-fold higher in the IF/TA group relative to that observed in the control group. We identified and validated DEGs related to IF/TA progression at one-year post-transplantation. Specifically, we identified ADAMTS2 as a potential IF/TA biomarker.
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Affiliation(s)
- Hyun Kyung Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea; (H.K.L.)
| | - Na Hyun Jung
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea; (H.K.L.)
| | - Da Eun Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea; (H.K.L.)
| | - Hajeong Lee
- Division of Nephrology, Department of Internal Medicine, Seoul National University Hospital, Seoul 03080, Republic of Korea (Y.S.K.)
- Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Jaeseok Yang
- Transplantation Center, Seoul National University Hospital, Seoul 03080, Republic of Korea
- Division of Nephrology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Yon Su Kim
- Division of Nephrology, Department of Internal Medicine, Seoul National University Hospital, Seoul 03080, Republic of Korea (Y.S.K.)
- Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Seung Seok Han
- Division of Nephrology, Department of Internal Medicine, Seoul National University Hospital, Seoul 03080, Republic of Korea (Y.S.K.)
- Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Nayoung Han
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea; (H.K.L.)
- College of Pharmacy, Jeju National University, Jeju 63243, Republic of Korea
| | - In-Wha Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea; (H.K.L.)
| | - Jung Mi Oh
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea; (H.K.L.)
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García-Castaño A, Gómez-Conde S, Gondra L, Herrero M, Aguirre M, de la Hoz AB, Castaño L, Madariaga L. Genotypic variability in patients with clinical diagnosis of Bartter syndrome type 3. Sci Rep 2023; 13:12587. [PMID: 37537162 PMCID: PMC10400606 DOI: 10.1038/s41598-023-38179-6] [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: 01/13/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023] Open
Abstract
Bartter syndrome (BS) is a salt-losing hereditary tubulopathy characterized by hypokalemic metabolic alkalosis with secondary hyperaldosteronism. Confirmatory molecular diagnosis may be difficult due to genetic heterogeneity and overlapping of clinical symptoms. The aim of our study was to describe the different molecular findings in patients with a clinical diagnosis of classic BS. We included 27 patients (26 families) with no identified pathogenic variants in CLCNKB. We used a customized Ion AmpliSeq Next-Generation Sequencing panel including 44 genes related to renal tubulopathies. We detected pathogenic or likely pathogenic variants in 12 patients (44%), reaching a conclusive genetic diagnosis. Variants in SLC12A3 were found in 6 (Gitelman syndrome). Median age at diagnosis was 14.6 years (range 0.1-31), with no history of prematurity or polyhydramnios. Serum magnesium level was low in 2 patients (33%) but urinary calcium excretion was normal or low in all, with no nephrocalcinosis. Variants in SLC12A1 were found in 3 (BS type 1); and in KCNJ1 in 1 (BS type 2). These patients had a history of polyhydramnios in 3 (75%), and the mean gestational age was 34.2 weeks (SD 1.7). The median age at diagnosis was 1.8 years (range 0.1-6). Chronic kidney disease and nephrocalcinosis were present in 1 (25%) and 3 (75%) patients, respectively. A variant in CLCN5 was found in one patient (Dent disease), and in NR3C2 in another patient (Geller syndrome). Genetic diagnosis of BS is heterogeneous as different tubulopathies can present with a similar clinical picture. The use of gene panels in these diseases becomes more efficient than the study gene by gene with Sanger sequencing.
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Affiliation(s)
- Alejandro García-Castaño
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
| | - Sara Gómez-Conde
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain
| | - Leire Gondra
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain
| | - María Herrero
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain
| | - Mireia Aguirre
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain
| | - Ana-Belén de la Hoz
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
| | - Luis Castaño
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain
| | - Leire Madariaga
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain.
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain.
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain.
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11
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Yang G, Liu R, Rezaei S, Liu X, Wan YJY. Uncovering the Gut-Liver Axis Biomarkers for Predicting Metabolic Burden in Mice. Nutrients 2023; 15:3406. [PMID: 37571345 PMCID: PMC10421148 DOI: 10.3390/nu15153406] [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] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/28/2023] [Accepted: 07/28/2023] [Indexed: 08/13/2023] Open
Abstract
Western diet (WD) intake, aging, and inactivation of farnesoid X receptor (FXR) are risk factors for metabolic and chronic inflammation-related health issues ranging from metabolic dysfunction-associated steatotic liver disease (MASLD) to dementia. The progression of MASLD can be escalated when those risks are combined. Inactivation of FXR, the receptor for bile acid (BA), is cancer prone in both humans and mice. The current study used multi-omics including hepatic transcripts, liver, serum, and urine metabolites, hepatic BAs, as well as gut microbiota from mouse models to classify those risks using machine learning. A linear support vector machine with K-fold cross-validation was used for classification and feature selection. We have identified that increased urine sucrose alone achieved 91% accuracy in predicting WD intake. Hepatic lithocholic acid and serum pyruvate had 100% and 95% accuracy, respectively, to classify age. Urine metabolites (decreased creatinine and taurine as well as increased succinate) or increased gut bacteria (Dorea, Dehalobacterium, and Oscillospira) could predict FXR deactivation with greater than 90% accuracy. Human disease relevance is partly revealed using the metabolite-disease interaction network. Transcriptomics data were also compared with the human liver disease datasets. WD-reduced hepatic Cyp39a1 (cytochrome P450 family 39 subfamily a member 1) and increased Gramd1b (GRAM domain containing 1B) were also changed in human liver cancer and metabolic liver disease, respectively. Together, our data contribute to the identification of noninvasive biomarkers within the gut-liver axis to predict metabolic status.
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Affiliation(s)
- Guiyan Yang
- Department of Medical Pathology, Laboratory Medicine in Sacramento, University of California, Davis, CA 95817, USA;
| | - Rex Liu
- Department of Computer Science, University of California, Davis, CA 95616, USA; (R.L.); (S.R.); (X.L.)
| | - Shahbaz Rezaei
- Department of Computer Science, University of California, Davis, CA 95616, USA; (R.L.); (S.R.); (X.L.)
| | - Xin Liu
- Department of Computer Science, University of California, Davis, CA 95616, USA; (R.L.); (S.R.); (X.L.)
| | - Yu-Jui Yvonne Wan
- Department of Medical Pathology, Laboratory Medicine in Sacramento, University of California, Davis, CA 95817, USA;
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12
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Hosoya M, Iwabu K, Kitama T, Nishiyama T, Oishi N, Okano H, Ozawa H. Development of cochlear spiral ligament fibrocytes of the common marmoset, a nonhuman model animal. Sci Rep 2023; 13:11789. [PMID: 37479821 PMCID: PMC10362005 DOI: 10.1038/s41598-023-39003-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 07/18/2023] [Indexed: 07/23/2023] Open
Abstract
Spiral ligament fibrocytes generate potassium gradients, which hair cells require to convert mechanical sound waves into electrical palsy. Together with the stria vascularis, they regulate endolymph electrolyte homeostasis. Developing spiral ligament fibrocytes and generating endocochlear potential with an appropriate endolymph ion composition are essential for hearing. Understanding spiral ligament fibrocyte development is useful for studying age-related and genetic hearing loss, as well as for regenerative therapy and cochlear immunology. Despite interspecies differences, most studies of cochlear development have been conducted in rodent models due to the difficulty of using human fetal samples. This study investigated the cochlear development of spiral ligament fibrocytes in a small New World monkey species, the common marmoset (Callithrix jacchus). We examined the developmental expression of specific genes in spiral ligament fibrocytes, including those essential for the generation of endolymphatic potential. Our results showed that this animal model of spiral ligament fibrocyte development is similar to that of humans and is a suitable alternative for the analysis of human cochlear development. The time course established in this study will be useful for studying the primate-specific developmental biology of the inner ear, which may lead to novel treatment strategies for human hearing loss.
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Affiliation(s)
- Makoto Hosoya
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Kaho Iwabu
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Tsubasa Kitama
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Takanori Nishiyama
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Naoki Oishi
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan
- Laboratory for Marmoset Neural Architecture, Center for Brain Science, RIKEN, 2-1 Hirosawa Wako, Saitama, 351-0193, Japan
| | - Hiroyuki Ozawa
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan
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13
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Ferreira G, Santander A, Cardozo R, Chavarría L, Domínguez L, Mujica N, Benítez M, Sastre S, Sobrevia L, Nicolson GL. Nutrigenomics of inward rectifier potassium channels. Biochim Biophys Acta Mol Basis Dis 2023:166803. [PMID: 37406972 DOI: 10.1016/j.bbadis.2023.166803] [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: 03/20/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
Inwardly rectifying potassium (Kir) channels play a key role in maintaining the resting membrane potential and supporting potassium homeostasis. There are many variants of Kir channels, which are usually tetramers in which the main subunit has two trans-membrane helices attached to two N- and C-terminal cytoplasmic tails with a pore-forming loop in between that contains the selectivity filter. These channels have domains that are strongly modulated by molecules present in nutrients found in different diets, such as phosphoinositols, polyamines and Mg2+. These molecules can impact these channels directly or indirectly, either allosterically by modulation of enzymes or via the regulation of channel expression. A particular type of these channels is coupled to cell metabolism and inhibited by ATP (KATP channels, essential for insulin release and for the pathogenesis of metabolic diseases like diabetes mellitus). Genomic changes in Kir channels have a significant impact on metabolism, such as conditioning the nutrients and electrolytes that an individual can take. Thus, the nutrigenomics of ion channels is an important emerging field in which we are attempting to understand how nutrients and diets can affect the activity and expression of ion channels and how genomic changes in such channels may be the basis for pathological conditions that limit nutrition and electrolyte intake. In this contribution we briefly review Kir channels, discuss their nutrigenomics, characterize how different components in the diet affect their function and expression, and suggest how their genomic changes lead to pathological phenotypes that affect diet and electrolyte intake.
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Affiliation(s)
- Gonzalo Ferreira
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay.
| | - Axel Santander
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Romina Cardozo
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Luisina Chavarría
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Lucía Domínguez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Nicolás Mujica
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Milagros Benítez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Santiago Sastre
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo CP 11800, Uruguay
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; Medical School (Faculty of Medicine), Sao Paulo State University (UNESP), Brazil; University of Queensland, Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, 4029, Queensland, Australia; Tecnologico de Monterrey, Eutra, The Institute for Obesity Research (IOR), School of Medicine and Health Sciences, Monterrey, Nuevo León, Mexico
| | - Garth L Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA, USA
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Van Beusecum JP, Rianto F, Teakell J, Kon V, Sparks MA, Hoorn EJ, Kirabo A, Ramkumar N. Novel Concepts in Nephron Sodium Transport: A Physiological and Clinical Perspective. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:124-136. [PMID: 36868728 DOI: 10.1053/j.akdh.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 04/13/2023]
Abstract
The kidneys play a critical role in maintaining total body sodium (Na+) balance across a wide range of dietary intake, accomplished by a concerted effort involving multiple Na+ transporters along the nephron. Furthermore, nephron Na+ reabsorption and urinary Na+ excretion are closely linked to renal blood flow and glomerular filtration such that perturbations in either of them can modify Na+ transport along the nephron, ultimately resulting in hypertension and other Na+-retentive states. In this article, we provide a brief physiological overview of nephron Na+ transport and illustrate clinical syndromes and therapeutic agents that affect Na+ transporter function. We highlight recent advances in kidney Na+ transport, particularly the role of immune cells, lymphatics, and interstitial Na+ in regulating Na+ reabsorption, the emergence of potassium (K+) as a regulator of Na+ transport, and the evolution of the nephron to modulate Na+ transport.
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Affiliation(s)
- Justin P Van Beusecum
- Ralph H. Johnson VA Medical Center, Charleston, SC; Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, SC
| | - Fitra Rianto
- Division of Nephrology, Department of Medicine, Duke University School of Medicine and Renal Section, Durham VA Health Care System Durham, Durham, NC
| | - Jade Teakell
- Division of Renal Diseases and Hypertension, Department of Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, TX
| | - Valentina Kon
- Division of Nephrology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN
| | - Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University School of Medicine and Renal Section, Durham VA Health Care System Durham, Durham, NC
| | - Ewout J Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Annet Kirabo
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Nirupama Ramkumar
- Division of Nephrology and Hypertension, Department of Medicine, University of Utah Health, Salt Lake City, UT.
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15
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Ray E, Mohan K, Ahmad S, Wolf MTF. Physiology of a Forgotten Electrolyte-Magnesium Disorders. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:148-163. [PMID: 36868730 DOI: 10.1053/j.akdh.2022.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 11/26/2022] [Accepted: 12/06/2022] [Indexed: 03/05/2023]
Abstract
Magnesium (Mg2+) is the second most common intracellular cation and the fourth most abundant element on earth. However, Mg2+ is a frequently overlooked electrolyte and often not measured in patients. While hypomagnesemia is common in 15% of the general population, hypermagnesemia is typically only found in preeclamptic women after Mg2+ therapy and in patients with ESRD. Mild to moderate hypomagnesemia has been associated with hypertension, metabolic syndrome, type 2 diabetes mellitus, CKD, and cancer. Nutritional Mg2+ intake and enteral Mg2+ absorption are important for Mg2+ homeostasis, but the kidneys are the key regulators of Mg2+ homeostasis by limiting urinary excretion to less than 4% while the gastrointestinal tract loses over 50% of the Mg2+ intake in the feces. Here, we review the physiological relevance of Mg2+, the current knowledge of Mg2+ absorption in the kidneys and the gut, the different causes of hypomagnesemia, and a diagnostic approach on how to assess Mg2+ status. We highlight the latest discoveries of monogenetic conditions causing hypomagnesemia, which have enhanced our understanding of tubular Mg2+ absorption. We will also discuss external and iatrogenic causes of hypomagnesemia and advances in the treatment of hypomagnesemia.
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Affiliation(s)
- Evan Ray
- Renal-Electrolyte Division, Department of Internal Medicine, University of Pittsburgh, PA
| | - Krithika Mohan
- Department of Nephrology, Hosmat Hospital, HBR Layout, Bangalore, India
| | - Syeda Ahmad
- Renal-Electrolyte Division, Department of Internal Medicine, University of Pittsburgh, PA
| | - Matthias T F Wolf
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX.
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16
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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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17
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Viering DH, Hureaux M, Neveling K, Latta F, Kwint M, Blanchard A, Konrad M, Bindels RJ, Schlingmann KP, Vargas-Poussou R, de Baaij JH. Long-Read Sequencing Identifies Novel Pathogenic Intronic Variants in Gitelman Syndrome. J Am Soc Nephrol 2023; 34:333-345. [PMID: 36302598 PMCID: PMC10103101 DOI: 10.1681/asn.2022050627] [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: 05/30/2022] [Accepted: 10/17/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Gitelman syndrome is a salt-losing tubulopathy characterized by hypokalemic alkalosis and hypomagnesemia. It is caused by homozygous recessive or compound heterozygous pathogenic variants in SLC12A3 , which encodes the Na + -Cl - cotransporter (NCC). In up to 10% of patients with Gitelman syndrome, current genetic techniques detect only one specific pathogenic variant. This study aimed to identify a second pathogenic variant in introns, splice sites, or promoters to increase the diagnostic yield. METHODS Long-read sequencing of SLC12A3 was performed in 67 DNA samples from individuals with suspected Gitelman syndrome in whom a single likely pathogenic or pathogenic variant was previously detected. In addition, we sequenced DNA samples from 28 individuals with one variant of uncertain significance or no candidate variant. Midigene splice assays assessed the pathogenicity of novel intronic variants. RESULTS A second likely pathogenic/pathogenic variant was identified in 45 (67%) patients. Those with two likely pathogenic/pathogenic variants had a more severe electrolyte phenotype than other patients. Of the 45 patients, 16 had intronic variants outside of canonic splice sites (nine variants, mostly deep intronic, six novel), whereas 29 patients had an exonic variant or canonic splice site variant. Midigene splice assays of the previously known c.1670-191C>T variant and intronic candidate variants demonstrated aberrant splicing patterns. CONCLUSION Intronic pathogenic variants explain an important part of the missing heritability in Gitelman syndrome. Long-read sequencing should be considered in diagnostic workflows for Gitelman syndrome.
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Affiliation(s)
- Daan H.H.M. Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - 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, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Paris CardioVascular Research Center, Institut National de la Santé et de Recherche Médicale (INSERM) U970, Paris City University, Paris, France
| | - Kornelia Neveling
- Department of Human Genetics, 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
| | - Michael Kwint
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anne Blanchard
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, University of Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Martin Konrad
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - René J.M. Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - 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, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - 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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18
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Zhang C, Guo J. Diverse functions of the inward-rectifying potassium channel Kir5.1 and its relationship with human diseases. Front Physiol 2023; 14:1127893. [PMID: 36923292 PMCID: PMC10008857 DOI: 10.3389/fphys.2023.1127893] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/15/2023] [Indexed: 03/02/2023] Open
Abstract
The inward-rectifying potassium channel subunit Kir5.1, encoded by Kcnj16, can form functional heteromeric channels (Kir4.1/5.1 and Kir4.2/5.1) with Kir4.1 (encoded by Kcnj10) or Kir4.2 (encoded by Kcnj15). It is expressed in the kidneys, pancreas, thyroid, brain, and other organs. Although Kir5.1 cannot form functional homomeric channels in most cases, an increasing number of studies in recent years have found that the functions of this subunit should not be underestimated. Kir5.1 can confer intracellular pH sensitivity to Kir4.1/5.1 channels, which can act as extracellular potassium sensors in the renal distal convoluted tubule segment. This segment plays an important role in maintaining potassium and acid-base balances. This review summarizes the various pathophysiological processes involved in Kir5.1 and the expression changes of Kir5.1 as a differentially expressed gene in various cancers, as well as describing several other disease phenotypes caused by Kir5.1 dysfunction.
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Affiliation(s)
- Chaojie Zhang
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Jia Guo
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
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19
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Johnston JG, Wingo CS. Potassium Homeostasis and WNK Kinases in the Regulation of the Sodium-Chloride Cotransporter: Hyperaldosteronism and Its Metabolic Consequences. KIDNEY360 2022; 3:1823-1828. [PMID: 36514400 PMCID: PMC9717643 DOI: 10.34067/kid.0005752022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 10/12/2022] [Indexed: 12/05/2022]
Affiliation(s)
- Jermaine G. Johnston
- Department of Medicine, University of Florida, Gainesville, Florida,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida,Veterans Administration Medical Center, North Florida/South Georgia Veterans Health Administration, Gainesville, Florida
| | - Charles S. Wingo
- Department of Medicine, University of Florida, Gainesville, Florida,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida,Veterans Administration Medical Center, North Florida/South Georgia Veterans Health Administration, Gainesville, Florida
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20
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Which patients with CKD will benefit from genomic sequencing? Synthesizing progress to illuminate the future. Curr Opin Nephrol Hypertens 2022; 31:541-547. [PMID: 36093902 PMCID: PMC9594128 DOI: 10.1097/mnh.0000000000000836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE OF REVIEW This review will summarize and synthesize recent findings in regard to monogenic kidney disorders, including how that evidence is being translated into practice. It will add to existing key knowledge to provide context for clinicians in consolidating existing practice and approaches. RECENT FINDINGS Whilst there are long established factors, which indicate increased likelihood of identifying a monogenic cause for kidney disease, these can now be framed in terms of the identification of new genes, new indications for genomic testing and new evidence for clinical utility of genomic testing in nephrology. Further, inherent in the use of genomics in nephrology are key concepts including robust informed consent, variant interpretation and return of results. Recent findings of variants in genes related to complex or broader kidney phenotypes are emerging in addition to understanding of de novo variants. Phenocopy phenomena are indicating a more pragmatic use of broader gene panels whilst evidence is emerging of a role in unexplained kidney disease. Clinical utility is evolving but is being successfully demonstrated across multiple domains of outcome and practice. SUMMARY We provide an updated framework of evidence to guide application of genomic testing in chronic kidney disease (CKD), building upon existing principles and knowledge to indicate how the practice and implementation of this can be applied today. There are clearly established roles for genomic testing for some patients with CKD, largely those with suspected heritable forms, with these continuing to expand as new evidence emerges.
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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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Staruschenko A, Hodges MR, Palygin O. Kir5.1 channels: potential role in epilepsy and seizure disorders. Am J Physiol Cell Physiol 2022; 323:C706-C717. [PMID: 35848616 PMCID: PMC9448276 DOI: 10.1152/ajpcell.00235.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 11/22/2022]
Abstract
Inwardly rectifying potassium (Kir) channels are broadly expressed in many mammalian organ systems, where they contribute to critical physiological functions. However, the importance and function of the Kir5.1 channel (encoded by the KCNJ16 gene) have not been fully recognized. This review focuses on the recent advances in understanding the expression patterns and functional roles of Kir5.1 channels in fundamental physiological systems vital to potassium homeostasis and neurological disorders. Recent studies have described the role of Kir5.1-forming Kir channels in mouse and rat lines with mutations in the Kcnj16 gene. The animal research reveals distinct renal and neurological phenotypes, including pH and electrolyte imbalances, blunted ventilatory responses to hypercapnia/hypoxia, and seizure disorders. Furthermore, it was confirmed that these phenotypes are reminiscent of those in patient cohorts in which mutations in the KCNJ16 gene have also been identified, further suggesting a critical role for Kir5.1 channels in homeostatic/neural systems health and disease. Future studies that focus on the many functional roles of these channels, expanded genetic screening in human patients, and the development of selective small-molecule inhibitors for Kir5.1 channels, will continue to increase our understanding of this unique Kir channel family member.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida
- Hypertension and Kidney Research Center, University of South Florida, Tampa, Florida
- James A. Haley Veterans Hospital, Tampa, Florida
| | - Matthew R Hodges
- Department of Physiology and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Oleg Palygin
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
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Role of inwardly rectifying K+ channel 5.1 (Kir5.1) in the regulation of renal membrane transport. Curr Opin Nephrol Hypertens 2022; 31:479-485. [PMID: 35894283 DOI: 10.1097/mnh.0000000000000817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Kir5.1 interacts with Kir4.2 in proximal tubule and with Kir4.1 in distal convoluted tubule (DCT), connecting tubule (CNT) and cortical collecting duct (CCD) to form basolateral-K+-channels. Kir4.2/Kir5.1 and Kir4.1/Kir5.1 play an important role in regulating Na+/HCO3--transport of the proximal tubule and Na+/K+ -transport in the DCT/CNT/CCD. The main focus of this review is to provide an overview of the recent development in the field regarding the role of Kir5.1 regulating renal electrolyte transport in the proximal tubule and DCT. RECENT FINDINGS Loss-of-function-mutations of KCNJ16 cause a new form of tubulopathy, characterized by hypokalaemia, Na+-wasting, acid-base-imbalance and metabolic-acidosis. Abnormal bicarbonate transport induced by loss-of-function of KCNJ16-mutants is recapitulated in Kir4.2-knockout-(Kir4.2 KO) mice. Deletion of Kir5.1 also abolishes the effect of dietary Na+ and K+-intakes on the basolateral membrane voltage and NCC expression/activity. Long-term high-salt intake or high-K+-intake causes hyperkalaemic in Kir5.1-deficient mice. SUMMARY Kir4.2/Kir5.1 activity in the proximal tubule plays a key role in regulating Na+, K+ and bicarbonate-transport through regulating electrogenic-Na+-bicarbonate-cotransporter-(NBCe1) and type 3-Na+/H+-exchanger-(NHE3). Kir4.1/Kir5.1 activity of the DCT plays a critical role in mediating the effect of dietary-K+ and Na+-intakes on NCC activity/expression. As NCC determines the Na+ delivery rate to the aldosterone-sensitive distal nephron (ASDN), defective regulation of NCC during high-salt and high-K+ compromises renal K+ excretion and K+ homeostasis.
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Wang WH, Lin DH. Inwardly rectifying K + channels 4.1 and 5.1 (Kir4.1/Kir5.1) in the renal distal nephron. Am J Physiol Cell Physiol 2022; 323:C277-C288. [PMID: 35759440 PMCID: PMC9291425 DOI: 10.1152/ajpcell.00096.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The inwardly rectifying potassium channel (Kir) 4.1 (encoded by KCNJ10) interacts with Kir5.1 (encoded by KCNJ16) to form a major basolateral K+ channel in the renal distal convoluted tubule (DCT), connecting tubule (CNT), and the cortical collecting duct (CCD). Kir4.1/Kir5.1 heterotetramer plays an important role in regulating Na+ and K+ transport in the DCT, CNT, and CCD. A recent development in the field has firmly established the role of Kir4.1/Kir5.1 heterotetramer of the DCT in the regulation of thiazide-sensitive Na-Cl cotransporter (NCC). Changes in Kir4.1/Kir5.1 activity of the DCT are an essential step for the regulation of NCC expression/activity induced by dietary K+ and Na+ intakes and play a role in modulating NCC by type 2 angiotensin II receptor (AT2R), bradykinin type II receptor (BK2R), and β-adrenergic receptor. Since NCC activity determines the Na+ delivery rate to the aldosterone-sensitive distal nephron (ASDN), a distal nephron segment from late DCT to CCD, Kir4.1/Kir5.1 activity plays a critical role not only in the regulation of renal Na+ absorption but also in modulating renal K+ excretion and maintaining K+ homeostasis. Thus, Kir4.1/Kir5.1 activity serves as an important component of renal K+ sensing mechanism. The main focus of this review is to provide an overview regarding the role of Kir4.1 and Kir5.1 of the DCT and CCD in the regulation of renal K+ excretion and Na+ absorption.
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Affiliation(s)
- Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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25
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McDonough AA, Fenton RA. Potassium homeostasis: sensors, mediators, and targets. Pflugers Arch 2022; 474:853-867. [PMID: 35727363 PMCID: PMC10163916 DOI: 10.1007/s00424-022-02718-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 06/08/2022] [Accepted: 06/12/2022] [Indexed: 12/16/2022]
Abstract
Transmembrane potassium (K) gradients are key determinants of membrane potential that can modulate action potentials, control muscle contractility, and influence ion channel and transporter activity. Daily K intake is normally equal to the amount of K in the entire extracellular fluid (ECF) creating a critical challenge - how to maintain ECF [K] and membrane potential in a narrow range during feast and famine. Adaptations to maintain ECF [K] include sensing the K intake, sensing ECF [K] vs. desired set-point and activating mediators that regulate K distribution between ECF and ICF, and regulate renal K excretion. In this focused review, we discuss the basis of these adaptions, including (1) potential mechanisms for rapid feedforward signaling to kidney and muscle after a meal (before a rise in ECF [K]), (2) how skeletal muscles sense and respond to changes in ECF [K], (3) effects of K on aldosterone biosynthesis, and (4) how the kidney responds to changes in ECF [K] to modify K excretion. The concepts of sexual dimorphisms in renal K handling adaptation are introduced, and the molecular mechanisms that can account for the benefits of a K-rich diet to maintain cardiovascular health are discussed. Although the big picture of K homeostasis is becoming more clear, we also highlight significant pieces of the puzzle that remain to be solved, including knowledge gaps in our understanding of initiating signals, sensors and their connection to homeostatic adjustments of ECF [K].
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Affiliation(s)
- Alicia A McDonough
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, USA.
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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26
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Guo Y, Gao Y, Liu S. lncRNA XIST is associated with preeclampsia and mediates trophoblast cell invasion via miR-340-5p/KCNJ16 signaling pathway. Transpl Immunol 2022; 74:101666. [PMID: 35809813 DOI: 10.1016/j.trim.2022.101666] [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: 05/27/2021] [Revised: 07/03/2022] [Accepted: 07/04/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND Preeclampsia (PE) is a syndrome commonly occurring among the pregnant. Shallow trophoblast invasion is considered to be closely related to PE. Therefore, in trophoblast cells, we explored the potential mechanisms of lncRNA XIST in the modulation of trophoblast invasion and proliferation. METHODS GEO online analyzer was used to screen the abnormally expressed RNAs in placenta tissues from patients with severe PE and healthy controls. The prediction of target bindings was performed on TargetScan and starBase. Transfection was conducted to regulate the RNA expression levels in trophoblast cells, HTR-8/SVneo. RT-qPCR measured expression of lncRNA XIST, miR-340-5p and KCNJ16. The CCK-8 assay examined cell viability. Flow cytometer analyzed apoptosis and luciferase assay determined the luciferase activity. Transwell assays detected the invasion and western blot verified the changes in protein expression of MMP2, MMP9 and KCNJ16 in trophoblast cells. RESULTS lncRNA XIST expression was enhanced in PE patients. Upregulation of lncRNA XIST in HTR-8/SVneo cells inhibited the cell proliferation and invasion, and induced apoptosis. XIST upregulation inhibited MMP2 and MMP9 protein expression. lncRNA XIST/ KCNJ16 interplayed as ceRNAs of miR-340-5p. Specifically,miR-340-5p overexpression reversed the effect of XIST upregulation on the cell apoptosis, proliferation and invasive ability and the knockdown of KCNJ16 could add to the effect of miR-340-5p overexpression in HTR-8/SVneo. CONCLUSION lncRNA XIST was upregulated in PE. Upregulation of lncRNA XIST exerted the inhibitory effects on the proliferation and invasion of trophoblast cells through the interactions with miR-340-5p/KCNJ16, which suggests that the lncRNA XIST/miR-340-5p/KCNJ16 axis might play a role in PE.
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Affiliation(s)
- Yuling Guo
- Tianjin Key Laboratory of human development and reproductive regulation, Tianjin Central Hospital of Gynecology Obstetrics, No. 156 Nankai Sanma Road Nankai District, Tianjin, 300100, China
| | - Yiping Gao
- Tianjin Key Laboratory of human development and reproductive regulation, Tianjin Central Hospital of Gynecology Obstetrics, No. 156 Nankai Sanma Road Nankai District, Tianjin, 300100, China
| | - Shasha Liu
- Tianjin Key Laboratory of human development and reproductive regulation, Tianjin Central Hospital of Gynecology Obstetrics, No. 156 Nankai Sanma Road Nankai District, Tianjin, 300100, China.
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27
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Vargas-Poussou R, Claverie-Martin F, Prot-Bertoye C, Carotti V, van der Wijst J, Perdomo-Ramirez A, Fraga-Rodriguez GM, Hureaux M, Bos C, Latta F, Houillier P, Hoenderop JGJ, de Baaij JHF. Possible role for rare TRPM7 variants in patients with hypomagnesaemia with secondary hypocalcaemia. Nephrol Dial Transplant 2022; 38:679-690. [PMID: 35561741 PMCID: PMC9976740 DOI: 10.1093/ndt/gfac182] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Hypomagnesaemia with secondary hypocal-caemia (HSH) is a rare autosomal recessive disorder caused by pathogenic variants in TRPM6, encoding the channel-kinase transient receptor potential melastatin type 6. Patients have very low serum magnesium (Mg2+) levels and suffer from muscle cramps and seizures. Despite genetic testing, a subgroup of HSH patients remains without a diagnosis. METHODS In this study, two families with an HSH phenotype but negative for TRPM6 pathogenic variants were subjected to whole exome sequencing. Using a complementary combination of biochemical and functional analyses in overexpression systems and patient-derived fibroblasts, the effect of the TRPM7-identified variants on Mg2+ transport was examined. RESULTS For the first time, variants in TRPM7 were identified in two families as a potential cause for hereditary HSH. Patients suffer from seizures and muscle cramps due to magnesium deficiency and episodes of hypocalcaemia. In the first family, a splice site variant caused the incorporation of intron 1 sequences into the TRPM7 messenger RNA and generated a premature stop codon. As a consequence, patient-derived fibroblasts exhibit decreased cell growth. In the second family, a heterozygous missense variant in the pore domain resulted in decreased TRPM7 channel activity. CONCLUSIONS We establish TRPM7 as a prime candidate gene for autosomal dominant hypomagnesaemia and secondary hypocalcaemia. Screening of unresolved patients with hypocalcaemia and secondary hypocalcaemia may further establish TRPM7 pathogenic variants as a novel Mendelian disorder.
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Affiliation(s)
| | | | | | - Valentina Carotti
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ana Perdomo-Ramirez
- Unidad de Investigación, Renal Tube Group, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | | | - Marguerite Hureaux
- Département de Génétique, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Hôpital Européen Georges Pompidou, Paris, France
| | - Caro Bos
- 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
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, CNRS, Paris, France,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France,Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Paris, France
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Mechanisms of ion transport regulation by HNF1β in the kidney: beyond transcriptional regulation of channels and transporters. Pflugers Arch 2022; 474:901-916. [PMID: 35554666 PMCID: PMC9338905 DOI: 10.1007/s00424-022-02697-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 01/01/2023]
Abstract
Hepatocyte nuclear factor 1β (HNF1β) is a transcription factor essential for the development and function of the kidney. Mutations in and deletions of HNF1β cause autosomal dominant tubule interstitial kidney disease (ADTKD) subtype HNF1β, which is characterized by renal cysts, diabetes, genital tract malformations, and neurodevelopmental disorders. Electrolyte disturbances including hypomagnesemia, hyperuricemia, and hypocalciuria are common in patients with ADTKD-HNF1β. Traditionally, these electrolyte disturbances have been attributed to HNF1β-mediated transcriptional regulation of gene networks involved in ion transport in the distal part of the nephron including FXYD2, CASR, KCNJ16, and FXR. In this review, we propose additional mechanisms that may contribute to the electrolyte disturbances observed in ADTKD-HNF1β patients. Firstly, kidney development is severely affected in Hnf1b-deficient mice. HNF1β is required for nephron segmentation, and the absence of the transcription factor results in rudimentary nephrons lacking mature proximal tubule, loop of Henle, and distal convoluted tubule cluster. In addition, HNF1β is proposed to be important for apical-basolateral polarity and tight junction integrity in the kidney. Interestingly, cilia formation is unaffected by Hnf1b defects in several models, despite the HNF1β-mediated transcriptional regulation of many ciliary genes. To what extent impaired nephron segmentation, apical-basolateral polarity, and cilia function contribute to electrolyte disturbances in HNF1β patients remains elusive. Systematic phenotyping of Hnf1b mouse models and the development of patient-specific kidney organoid models will be essential to advance future HNF1β research.
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29
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McClenahan SJ, Kent CN, Kharade SV, Isaeva E, Williams JC, Han C, Terker A, Gresham R, Lazarenko RM, Days EL, Romaine IM, Bauer JA, Boutaud O, Sulikowski GA, Harris R, Weaver CD, Staruschenko A, Lindsley CW, Denton JS. VU6036720: The First Potent and Selective In Vitro Inhibitor of Heteromeric Kir4.1/5.1 Inward Rectifier Potassium Channels. Mol Pharmacol 2022; 101:357-370. [PMID: 35246480 PMCID: PMC9092466 DOI: 10.1124/molpharm.121.000464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/14/2022] [Indexed: 01/14/2023] Open
Abstract
Heteromeric Kir4.1/Kir5.1 (KCNJ10/KCNJ16) inward rectifier potassium (Kir) channels play key roles in the brain and kidney, but pharmacological tools for probing their physiology and therapeutic potential have not been developed. Here, we report the discovery, in a high-throughput screening of 80,475 compounds, of the moderately potent and selective inhibitor VU0493690, which we selected for characterization and chemical optimization. VU0493690 concentration-dependently inhibits Kir4.1/5.1 with an IC50 of 0.96 μM and exhibits at least 10-fold selectivity over Kir4.1 and ten other Kir channels. Multidimensional chemical optimization of VU0493690 led to the development of VU6036720, the most potent (IC50 = 0.24 μM) and selective (>40-fold over Kir4.1) Kir4.1/5.1 inhibitor reported to date. Cell-attached patch single-channel recordings revealed that VU6036720 inhibits Kir4.1/5.1 activity through a reduction of channel open-state probability and single-channel current amplitude. Elevating extracellular potassium ion by 20 mM shifted the IC50 6.8-fold, suggesting that VU6036720 is a pore blocker that binds in the ion-conduction pathway. Mutation of the "rectification controller" asparagine 161 to glutamate (N161E), which is equivalent to small-molecule binding sites in other Kir channels, led to a strong reduction of inhibition by VU6036720. Renal clearance studies in mice failed to show a diuretic response that would be consistent with inhibition of Kir4.1/5.1 in the renal tubule. Drug metabolism and pharmacokinetics profiling revealed that high VU6036720 clearance and plasma protein binding may prevent target engagement in vivo. In conclusion, VU6036720 represents the current state-of-the-art Kir4.1/5.1 inhibitor that should be useful for probing the functions of Kir4.1/5.1 in vitro and ex vivo. SIGNIFICANCE STATEMENT: Heteromeric inward rectifier potassium (Kir) channels comprising Kir4.1 and Kir5.1 subunits play important roles in renal and neural physiology and may represent inhibitory drug targets for hypertension and edema. Herein, we employ high-throughput compound library screening, patch clamp electrophysiology, and medicinal chemistry to develop and characterize the first potent and specific in vitro inhibitor of Kir4.1/5.1, VU6036720, which provides proof-of-concept that drug-like inhibitors of this channel may be developed.
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Affiliation(s)
- Samantha J McClenahan
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Caitlin N Kent
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Sujay V Kharade
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Elena Isaeva
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Jade C Williams
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Changho Han
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Andrew Terker
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Robert Gresham
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Roman M Lazarenko
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Emily L Days
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Ian M Romaine
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Joshua A Bauer
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Olivier Boutaud
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Gary A Sulikowski
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Raymond Harris
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - C David Weaver
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Alexander Staruschenko
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Craig W Lindsley
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
| | - Jerod S Denton
- Departments of Anesthesiology (S.J.M., S.V.K., R.G., R.M.L., J.S.D.), Biochemistry (J.A.B.), Chemistry (C.N.K., J.C.W., I.M.R., C.D.W., G.A.S., C.W.L.), Pharmacology (E.L.D., C.D.W., C.W.L., C.H., O.B., J.S.D.), and Nephrology (A.T., R.H.), and Vanderbilt Institute of Chemical Biology (J.A.B., G.S., C.D.W., C.W.L., J.S.D.), Vanderbilt University, Nashville, Tennessee; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin (E.I.); and Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida (A.S.)
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Alhasan K, D'Alessandri-Silva C, Mongia A, Topaloglu R, Tasic V, Filler G. Young Adults With Hereditary Tubular Diseases: Practical Aspects for Adult-Focused Colleagues. Adv Chronic Kidney Dis 2022; 29:292-307. [PMID: 36084976 DOI: 10.1053/j.ackd.2021.11.004] [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: 09/21/2021] [Revised: 11/07/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Recent advances in the management of kidney tubular diseases have resulted in a significant cohort of adolescents and young adults transitioning from pediatric- to adult-focused care. Most of the patients under adult-focused care have glomerular diseases, whereas rarer tubular diseases form a considerable proportion of pediatric patients. The purpose of this review is to highlight the clinical signs and symptoms of tubular disorders, as well as their diagnostic workup, including laboratory findings and imaging, during young adulthood. We will then discuss more common disorders such as cystinosis, cystinuria, distal kidney tubular acidosis, congenital nephrogenic diabetes insipidus, Dent disease, rickets, hypercalciuria, and syndromes such as Bartter, Fanconi, Gitelman, Liddle, and Lowe. This review is a practical guide on the diagnostic and therapeutic approach of tubular conditions affecting young adults who are transitioning to adult-focused care.
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Affiliation(s)
- Khalid Alhasan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Cynthia D'Alessandri-Silva
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, and Nephrology, Connecticut Children's Medical Center, Hartford, CT
| | - Anil Mongia
- Department of Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY
| | - Rezan Topaloglu
- Department of Paediatrics, Division of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Velibor Tasic
- University Children's Hospital, Medical School, Skopje, North Macedonia
| | - Guido Filler
- Department of Paediatrics, Division of Pediatric Nephrology, Western University, London, ON, Canada; Department of Medicine, Western University, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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31
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Lo J, Forst AL, Warth R, Zdebik AA. EAST/SeSAME Syndrome and Beyond: The Spectrum of Kir4.1- and Kir5.1-Associated Channelopathies. Front Physiol 2022; 13:852674. [PMID: 35370765 PMCID: PMC8965613 DOI: 10.3389/fphys.2022.852674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/08/2022] [Indexed: 12/13/2022] Open
Abstract
In 2009, two groups independently linked human mutations in the inwardly rectifying K+ channel Kir4.1 (gene name KCNJ10) to a syndrome affecting the central nervous system (CNS), hearing, and renal tubular salt reabsorption. The autosomal recessive syndrome has been named EAST (epilepsy, ataxia, sensorineural deafness, and renal tubulopathy) or SeSAME syndrome (seizures, sensorineural deafness, ataxia, intellectual disability, and electrolyte imbalance), accordingly. Renal dysfunction in EAST/SeSAME patients results in loss of Na+, K+, and Mg2+ with urine, activation of the renin-angiotensin-aldosterone system, and hypokalemic metabolic alkalosis. Kir4.1 is highly expressed in affected organs: the CNS, inner ear, and kidney. In the kidney, it mostly forms heteromeric channels with Kir5.1 (KCNJ16). Biallelic loss-of-function mutations of Kir5.1 can also have disease significance, but the clinical symptoms differ substantially from those of EAST/SeSAME syndrome: although sensorineural hearing loss and hypokalemia are replicated, there is no alkalosis, but rather acidosis of variable severity; in contrast to EAST/SeSAME syndrome, the CNS is unaffected. This review provides a framework for understanding some of these differences and will guide the reader through the growing literature on Kir4.1 and Kir5.1, discussing the complex disease mechanisms and the variable expression of disease symptoms from a molecular and systems physiology perspective. Knowledge of the pathophysiology of these diseases and their multifaceted clinical spectrum is an important prerequisite for making the correct diagnosis and forms the basis for personalized therapies.
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Affiliation(s)
- Jacky Lo
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Anna-Lena Forst
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Anselm A. Zdebik
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- Centre for Nephrology, University College London, London, United Kingdom
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32
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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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Wieërs MLAJ, Mulder J, Rotmans JI, Hoorn EJ. Potassium and the kidney: a reciprocal relationship with clinical relevance. Pediatr Nephrol 2022; 37:2245-2254. [PMID: 35195759 PMCID: PMC9395506 DOI: 10.1007/s00467-022-05494-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/02/2022] [Accepted: 02/02/2022] [Indexed: 10/26/2022]
Abstract
By controlling urinary potassium excretion, the kidneys play a key role in maintaining whole-body potassium homeostasis. Conversely, low urinary potassium excretion (as a proxy for insufficient dietary intake) is increasingly recognized as a risk factor for the progression of kidney disease. Thus, there is a reciprocal relationship between potassium and the kidney: the kidney regulates potassium balance but potassium also affects kidney function. This review explores this relationship by discussing new insights into kidney potassium handling derived from recently characterized tubulopathies and studies on sexual dimorphism. These insights reveal a central but non-exclusive role for the distal convoluted tubule in sensing potassium and subsequently modifying the activity of the sodium-chloride cotransporter. This is another example of reciprocity: activation of the sodium-chloride cotransporter not only reduces distal sodium delivery and therefore potassium secretion but also increases salt sensitivity. This mechanism helps explain the well-known relationship between dietary potassium and blood pressure. Remarkably, in children, blood pressure is related to dietary potassium but not sodium intake. To explore how potassium deficiency can cause kidney injury, we review the mechanisms of hypokalemic nephropathy and discuss if these mechanisms may explain the association between low dietary potassium intake and adverse kidney outcomes. We discuss if potassium should be repleted in patients with kidney disease and what role dietary potassium plays in the risk of hyperkalemia. Supported by data and physiology, we reach the conclusion that we should view potassium not only as a potentially dangerous cation but also as a companion in the battle against kidney disease.
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Affiliation(s)
- Michiel L. A. J. Wieërs
- grid.5645.2000000040459992XDepartment of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Room Ns403, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Jaap Mulder
- grid.5645.2000000040459992XDepartment of Pediatrics, Division of Pediatric Nephrology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands ,grid.10419.3d0000000089452978Department of Pediatrics, Division of Pediatric Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Joris I. Rotmans
- grid.10419.3d0000000089452978Department of Internal Medicine, Division of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ewout J. Hoorn
- grid.5645.2000000040459992XDepartment of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Room Ns403, PO Box 2040, 3000 CA Rotterdam, The Netherlands
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34
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Castañeda-Bueno M, Ellison DH, Gamba G. Molecular mechanisms for the modulation of blood pressure and potassium homeostasis by the distal convoluted tubule. EMBO Mol Med 2021; 14:e14273. [PMID: 34927382 PMCID: PMC8819348 DOI: 10.15252/emmm.202114273] [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: 09/14/2021] [Revised: 11/17/2021] [Accepted: 12/01/2021] [Indexed: 12/15/2022] Open
Abstract
Epidemiological and clinical observations have shown that potassium ingestion is inversely correlated with arterial hypertension prevalence and cardiovascular mortality. The higher the dietary potassium, the lower the blood pressure and mortality. This phenomenon is explained, at least in part, by the interaction between salt reabsorption in the distal convoluted tubule (DCT) and potassium secretion in the connecting tubule/collecting duct of the mammalian nephron: In order to achieve adequate K+ secretion levels under certain conditions, salt reabsorption in the DCT must be reduced. Because salt handling by the kidney constitutes the basis for the long‐term regulation of blood pressure, losing salt prevents hypertension. Here, we discuss how the study of inherited diseases in which salt reabsorption in the DCT is affected has revealed the molecular players, including membrane transporters and channels, kinases, and ubiquitin ligases that form the potassium sensing mechanism of the DCT and the processes through which the consequent adjustments in salt reabsorption are achieved.
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Affiliation(s)
- María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, OR, USA.,Oregon Clinical & Translational Research Institute, Oregon Health & Science University, Portland, OR, USA.,VA Portland Health Care System, Portland, OR, USA
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico.,Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
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35
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Isaeva E, Bohovyk R, Fedoriuk M, Shalygin A, Klemens CA, Zietara A, Levchenko V, Denton JS, Staruschenko A, Palygin O. Crosstalk between ENaC and basolateral K ir 4.1/K ir 5.1 channels in the cortical collecting duct. Br J Pharmacol 2021; 179:2953-2968. [PMID: 34904226 DOI: 10.1111/bph.15779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 10/06/2021] [Accepted: 12/06/2021] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND AND PURPOSE Inwardly rectifying K+ (Kir ) channels located on the basolateral membrane of epithelial cells of the distal nephron play a crucial role in K+ handling and blood pressure control, making these channels an attractive target for the treatment of hypertension. The purpose of the present study was to determine how the inhibition of basolateral Kir 4.1/Kir 5.1 heteromeric K+ channel affects epithelial sodium channel (ENaC)-mediated Na+ transport in the principal cells of cortical collecting duct (CCD). EXPERIMENTAL APPROACH The effect of fluoxetine, amitriptyline, and recently developed Kir inhibitor, VU0134992, on the activity of Kir 4.1, Kir 4.1/Kir 5.1, and ENaC were tested using electrophysiological approaches in Chinese hamster ovary (CHO) cells transfected with respective channel subunits, cultured polarized epithelial mCCDcl1 cells, and freshly isolated rat and human CCD tubules. To test the effect of pharmacological Kir 4.1/Kir 5.1 inhibition on electrolyte homeostasis in vivo and corresponding changes in distal tubule transport, Dahl salt-sensitive rats were injected with amitriptyline (15 mg kg-1 day-1 ) for three days. KEY RESULTS We found that inhibition of Kir 4.1/Kir 5.1, but not Kir 4.1 channel, depolarizes cell membrane, induces the elevation of intracellular Ca2+ concentration, and suppresses ENaC activity. Furthermore, we demonstrate that amitriptyline administration leads to a significant drop in plasma K+ level, triggering sodium excretion and diuresis. CONCLUSION AND IMPLICATIONS Present data uncovers a specific role of the Kir 4.1/Kir 5.1 channel in the modulation of ENaC activity and emphasizes the potential for using Kir 4.1/Kir 5.1 inhibitors to regulate electrolyte homeostasis and blood pressure.
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Affiliation(s)
- Elena Isaeva
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Ruslan Bohovyk
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Mykhailo Fedoriuk
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Alexey Shalygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Christine A Klemens
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Adrian Zietara
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Vladislav Levchenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Jerod S Denton
- Department of Anesthesiology and Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA.,Clement J. Zablocki VA Medical Center, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, USA
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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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Hyndman KA, Isaeva E, Palygin O, Mendoza LD, Rodan AR, Staruschenko A, Pollock JS. Role of collecting duct principal cell NOS1β in sodium and potassium homeostasis. Physiol Rep 2021; 9:e15080. [PMID: 34665521 PMCID: PMC8525323 DOI: 10.14814/phy2.15080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/15/2021] [Accepted: 09/27/2021] [Indexed: 12/15/2022] Open
Abstract
The nitric oxide (NO)-generating enzyme, NO synthase-1β (NOS1β), is essential for sodium (Na+ ) homeostasis and blood pressure control. We previously showed that collecting duct principal cell NOS1β is critical for inhibition of the epithelial sodium channel (ENaC) during high Na+ intake. Previous studies on freshly isolated cortical collecting ducts (CCD) demonstrated that exogenous NO promotes basolateral potassium (K+ ) conductance through basolateral channels, presumably Kir 4.1 (Kcnj10) and Kir 5.1 (Kcnj16). We, therefore, investigated the effects of NOS1β knockout on Kir 4.1/Kir 5.1 channel activity. Indeed, in CHO cells overexpressing NOS1β and Kir 4.1/Kir 5.1, the inhibition of NO signaling decreased channel activity. Male littermate control and principal cell NOS1β knockout mice (CDNOS1KO) on a 7-day, 4% NaCl diet (HSD) were used to detect changes in basolateral K+ conductance. We previously demonstrated that CDNOS1KO mice have high circulating aldosterone despite a high-salt diet and appropriately suppressed renin. We observed greater Kir 4.1 cortical abundance and significantly greater Kir 4.1/Kir 5.1 single-channel activity in the principal cells from CDNOS1KO mice. Moreover, blocking aldosterone action with in vivo spironolactone treatment resulted in lower Kir 4.1 abundance and greater plasma K+ in the CDNOS1KO mice compared to controls. Lowering K+ content in the HSD prevented the high aldosterone and greater plasma Na+ of CDNOS1KO mice and normalized Kir 4.1 abundance. We conclude that during chronic HSD, lack of NOS1β leads to increased plasma K+ , enhanced circulating aldosterone, and activation of ENaC and Kir 4.1/Kir 5.1 channels. Thus, principal cell NOS1β is required for the regulation of both Na+ and K+ by the kidney.
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Affiliation(s)
- Kelly A. Hyndman
- Department of MedicineDivision of NephrologySection of Cardio‐Renal Physiology and MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Elena Isaeva
- Department of Cellular Biology, Neurobiology and AnatomyMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Oleg Palygin
- Division of NephrologyDepartment of MedicineMedical University of South CarolinaCharlestonSouth CarolinaUSA
| | - Luciano D. Mendoza
- Department of MedicineDivision of NephrologySection of Cardio‐Renal Physiology and MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Aylin R. Rodan
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUtahUSA
- The Department of Internal MedicineDivision of Nephrology and HypertensionUniversity of UtahSalt Lake CityUtahUSA
- The Department of Human GeneticsUniversity of UtahSalt Lake CityUtahUSA
- The Medical ServiceVeterans Affairs Salt Lake City Health Care SystemSalt Lake CityUtahUSA
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and PhysiologyUniversity of South FloridaTampaFloridaUSA
- The James A. Haley Veterans HospitalTampaFloridaUSA
| | - Jennifer S. Pollock
- Department of MedicineDivision of NephrologySection of Cardio‐Renal Physiology and MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
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Filler G, Salerno F, McIntyre CW, de Ferris MEDG. Animal, Human, and 23Na MRI Imaging Evidence for the Negative Impact of High Dietary Salt in Children. CURRENT PEDIATRICS REPORTS 2021; 9:110-117. [PMID: 34567839 PMCID: PMC8449209 DOI: 10.1007/s40124-021-00249-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/18/2021] [Indexed: 02/08/2023]
Abstract
PURPOSE OF THE REVIEW Conditions typically prevalent in adults such as hypertension, kidney stones, osteoporosis, and chronic kidney disease are increasing among adolescents and young adults (AYA). The purpose of this review is to describe the association of these conditions to a high salt diet among pediatric patients. RECENT FINDINGS We present animal, human, and 23Na MRI evidence associated with the negative impact of high dietary salt in children. Special focus is placed on novel 23Na MRI imaging which reveals the important concept of a third compartment for sodium storage in soft tissue. Finally, we make recommendations on who should not be on a low salt diet. SUMMARY A high salt intake predisposes children and AYA to considerable morbidity. We exhort the reader to engage in advocacy efforts to curve the incidence and prevalence of high salt-related life-limiting conditions.
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Affiliation(s)
- Guido Filler
- Departments of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, London, ON E3-206N6A 5W9 Canada
- Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Pathology & Laboratory Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Children’s Health Research Institute, University of Western Ontario, London, Canada
- Lilibeth Caberto Kidney Clinical Research Unit, London, ON Canada
| | - Fabio Salerno
- Lilibeth Caberto Kidney Clinical Research Unit, London, ON Canada
- Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Christopher William McIntyre
- Departments of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, London, ON E3-206N6A 5W9 Canada
- Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Children’s Health Research Institute, University of Western Ontario, London, Canada
- Lilibeth Caberto Kidney Clinical Research Unit, London, ON Canada
- Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
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