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Guo J, Zhang C, Zhao H, Yan Y, Liu Z. The key mediator of diabetic kidney disease: Potassium channel dysfunction. Genes Dis 2024; 11:101119. [PMID: 38523672 PMCID: PMC10958065 DOI: 10.1016/j.gendis.2023.101119] [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] [Received: 09/14/2021] [Revised: 06/11/2022] [Accepted: 06/04/2023] [Indexed: 03/26/2024] Open
Abstract
Diabetic kidney disease is a leading cause of end-stage renal disease, making it a global public health concern. The molecular mechanisms underlying diabetic kidney disease have not been elucidated due to its complex pathogenesis. Thus, exploring these mechanisms from new perspectives is the current focus of research concerning diabetic kidney disease. Ion channels are important proteins that maintain the physiological functions of cells and organs. Among ion channels, potassium channels stand out, because they are the most common and important channels on eukaryotic cell surfaces and function as the basis for cell excitability. Certain potassium channel abnormalities have been found to be closely related to diabetic kidney disease progression and genetic susceptibility, such as KATP, KCa, Kir, and KV. In this review, we summarized the roles of different types of potassium channels in the occurrence and development of diabetic kidney disease to discuss whether the development of DKD is due to potassium channel dysfunction and present new ideas for the treatment of DKD.
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Affiliation(s)
- Jia Guo
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Chaojie Zhang
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Hui Zhao
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Yufan Yan
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Zhangsuo Liu
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
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Grimm PR, Tatomir A, Rosenbaek LL, Kim BY, Li D, Delpire EJ, Fenton RA, Welling PA. Dietary potassium stimulates Ppp1Ca-Ppp1r1a dephosphorylation of kidney NaCl cotransporter and reduces blood pressure. J Clin Invest 2023; 133:e158498. [PMID: 37676724 PMCID: PMC10617769 DOI: 10.1172/jci158498] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 09/06/2023] [Indexed: 09/09/2023] Open
Abstract
Consumption of low dietary potassium, common with ultraprocessed foods, activates the thiazide-sensitive sodium chloride cotransporter (NCC) via the with no (K) lysine kinase/STE20/SPS1-related proline-alanine-rich protein kinase (WNK/SPAK) pathway to induce salt retention and elevate blood pressure (BP). However, it remains unclear how high-potassium "DASH-like" diets (dietary approaches to stop hypertension) inactivate the cotransporter and whether this decreases BP. A transcriptomics screen identified Ppp1Ca, encoding PP1A, as a potassium-upregulated gene, and its negative regulator Ppp1r1a, as a potassium-suppressed gene in the kidney. PP1A directly binds to and dephosphorylates NCC when extracellular potassium is elevated. Using mice genetically engineered to constitutively activate the NCC-regulatory kinase SPAK and thereby eliminate the effects of the WNK/SPAK kinase cascade, we confirmed that PP1A dephosphorylated NCC directly in a potassium-regulated manner. Prior adaptation to a high-potassium diet was required to maximally dephosphorylate NCC and lower BP in constitutively active SPAK mice, and this was associated with potassium-dependent suppression of Ppp1r1a and dephosphorylation of its cognate protein, inhibitory subunit 1 (I1). In conclusion, potassium-dependent activation of PP1A and inhibition of I1 drove NCC dephosphorylation, providing a mechanism to explain how high dietary K+ lowers BP. Shifting signaling of PP1A in favor of activation of WNK/SPAK may provide an improved therapeutic approach for treating salt-sensitive hypertension.
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Affiliation(s)
- P. Richard Grimm
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
| | - Anamaria Tatomir
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Lena L. Rosenbaek
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Bo Young Kim
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
| | - Dimin Li
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Eric J. Delpire
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennssee, USA
| | - Robert A. Fenton
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Paul A. Welling
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Physiology, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
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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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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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Nguyen NH, Brodsky JL. The cellular pathways that maintain the quality control and transport of diverse potassium channels. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194908. [PMID: 36638864 PMCID: PMC9908860 DOI: 10.1016/j.bbagrm.2023.194908] [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: 12/01/2022] [Revised: 12/20/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
Potassium channels are multi-subunit transmembrane proteins that permit the selective passage of potassium and play fundamental roles in physiological processes, such as action potentials in the nervous system and organismal salt and water homeostasis, which is mediated by the kidney. Like all ion channels, newly translated potassium channels enter the endoplasmic reticulum (ER) and undergo the error-prone process of acquiring post-translational modifications, folding into their native conformations, assembling with other subunits, and trafficking through the secretory pathway to reach their final destinations, most commonly the plasma membrane. Disruptions in these processes can result in detrimental consequences, including various human diseases. Thus, multiple quality control checkpoints evolved to guide potassium channels through the secretory pathway and clear potentially toxic, aggregation-prone misfolded species. We will summarize current knowledge on the mechanisms underlying potassium channel quality control in the secretory pathway, highlight diseases associated with channel misfolding, and suggest potential therapeutic routes.
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Affiliation(s)
- Nga H Nguyen
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA.
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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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Yekefallah M, Rasberry CA, van Aalst EJ, Browning HP, Amani R, Versteeg DB, Wylie BJ. Mutational Insight into Allosteric Regulation of Kir Channel Activity. ACS OMEGA 2022; 7:43621-43634. [PMID: 36506180 PMCID: PMC9730464 DOI: 10.1021/acsomega.2c04456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 11/10/2022] [Indexed: 06/08/2023]
Abstract
Potassium (K+) channels are regulated in part by allosteric communication between the helical bundle crossing, or inner gate, and the selectivity filter, or outer gate. This network is triggered by gating stimuli. In concert, there is an allosteric network which is a conjugated set of interactions which correlate long-range structural rearrangements necessary for channel function. Inward-rectifier K+ (Kir) channels favor inward K+ conductance, are ligand-gated, and help establish resting membrane potentials. KirBac1.1 is a bacterial Kir (KirBac) channel homologous to human Kir (hKir) channels. Additionally, KirBac1.1 is gated by the anionic phospholipid ligand phosphatidylglycerol (PG). In this study, we use site-directed mutagenesis to investigate residues involved in the KirBac1.1 gating mechanism and allosteric network we previously proposed using detailed solid-state NMR (SSNMR) measurements. Using fluorescence-based K+ and sodium (Na+) flux assays, we identified channel mutants with impaired function that do not alter selectivity of the channel. In tandem, we performed coarse grain molecular dynamics simulations, observing changes in PG-KirBac1.1 interactions correlated with mutant channel activity and contacts between the two transmembrane helices and pore helix tied to this behavior. Lipid affinity is closely tied to the proximity of two tryptophan residues on neighboring subunits which lure anionic lipids to a cationic pocket formed by a cluster of arginine residues. Thus, these simulations establish a structural and functional basis for the role of each mutated site in the proposed allosteric network. The experimental and simulated data provide insight into key functional residues involved in gating and lipid allostery of K+ channels. Our findings also have direct implications on the physiology of hKir channels due to conservation of many of the residues identified in this work from KirBac1.1.
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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: 7] [Impact Index Per Article: 3.5] [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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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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PKC regulation of ion channels: The involvement of PIP 2. J Biol Chem 2022; 298:102035. [PMID: 35588786 PMCID: PMC9198471 DOI: 10.1016/j.jbc.2022.102035] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 11/24/2022] Open
Abstract
Ion channels are integral membrane proteins whose gating has been increasingly shown to depend on the presence of the low-abundance membrane phospholipid, phosphatidylinositol (4,5) bisphosphate. The expression and function of ion channels is tightly regulated via protein phosphorylation by specific kinases, including various PKC isoforms. Several channels have further been shown to be regulated by PKC through altered surface expression, probability of channel opening, shifts in voltage dependence of their activation, or changes in inactivation or desensitization. In this review, we survey the impact of phosphorylation of various ion channels by PKC isoforms and examine the dependence of phosphorylated ion channels on phosphatidylinositol (4,5) bisphosphate as a mechanistic endpoint to control channel gating.
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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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Zhang DD, Zheng JY, Duan XP, Lin DH, Wang WH. ROMK channels are inhibited in the aldosterone-sensitive distal nephron of renal tubule Nedd4-2-deficient mice. Am J Physiol Renal Physiol 2022; 322:F55-F67. [PMID: 34843409 PMCID: PMC8714254 DOI: 10.1152/ajprenal.00306.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/18/2021] [Accepted: 11/27/2021] [Indexed: 01/03/2023] Open
Abstract
We used whole cell recording to examine the renal outer medullary K+ channel (ROMK or Kir1.1) and epithelial Na+ channel (ENaC) in the late distal convoluted tubule (DCT2)/initial connecting tubule (iCNT) and in the cortical collecting duct (CCD) of kidney tubule-specific neural precursor cell-expressed developmentally downregulated protein 4-2 (Nedd4-2) knockout mice (Ks-Nedd4-2 KO) and floxed neural precursor cell-expressed developmentally downregulated 4-like (Nedd4l) mice (control). Tertiapin Q (TPNQ)-sensitive K+ currents (ROMK) were smaller in both the DCT2/iCNT and CCD of Ks-Nedd4-2 KO mice on a normal diet than in control mice. Neither high dietary salt intake nor low dietary salt intake had a significant effect on ROMK activity in the DCT2/iCNT and CCD of control and Ks-Nedd4-2 KO mice. In contrast, high dietary K+ intake (HK) increased, whereas low dietary K+ intake (LK) decreased TPNQ-sensitive K+ currents in floxed Nedd4l mice. However, the effects of dietary K+ intake on ROMK channel activity were absent in Ks-Nedd4-2 KO mice since neither HK nor LK significantly affected TPNQ-sensitive K+ currents in the DCT2/iCNT and CCD. Moreover, TPNQ-sensitive K+ currents in the DCT2/iCNT and CCD of Ks-Nedd4-2 KO mice on HK were similar to those of control mice on LK. Amiloride-sensitive Na+ currents in the DCT2/iCNT and CCD were significantly higher in Ks-Nedd4-2 KO mice than in floxed Nedd4l mice on a normal K+ diet. HK increased ENaC activity of the DCT2/iCNT only in control mice, but HK stimulated ENaC of the CCD in both control and Ks-Nedd4-2 KO mice. Moreover, the HK-induced increase in amiloride-sensitive Na+ currents was larger in Ks-Nedd4-2 KO mice than in control mice. Deletion of Nedd4-2 increased with no lysine kinase 1 expression and abolished HK-induced inhibition of with no lysine kinase 1. We conclude that deletion of Nedd4-2 increases ENaC activity but decreases ROMK activity in the aldosterone-sensitive distal nephron and that HK fails to stimulate ROMK, but robustly increases ENaC activity in the CCD of Nedd4-2-deficient mice.NEW & NOTEWORTHY We demonstrate that renal outer medullary K+ (ROMK) channel activity is inhibited in the late distal convoluted tubule/initial connecting tubule and cortical collecting duct of neural precursor cell-expressed developmentally downregulated protein 4-2 (Nedd4-2)-deficient mice. Also, deletion of Nedd4-2 abolishes the stimulatory effect of dietary K+ intake on ROMK. The lack of high K+-induced stimulation of ROMK is associated with the absence of high K+-induced inhibition of with no lysine kinase 1.
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Affiliation(s)
- Dan-Dan Zhang
- Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, Guangdong, China
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Jun-Ya Zheng
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xin-Peng Duan
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
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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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15
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Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications. Handb Exp Pharmacol 2021; 267:277-356. [PMID: 34345939 DOI: 10.1007/164_2021_501] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K+ channels. In the present review we focus on placing the physiology and pharmacology of this K+ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.
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Schlingmann KP, Renigunta A, Hoorn EJ, Forst AL, Renigunta V, Atanasov V, Mahendran S, Barakat TS, Gillion V, Godefroid N, Brooks AS, Lugtenberg D, Lake J, Debaix H, Rudin C, Knebelmann B, Tellier S, Rousset-Rouvière C, Viering D, de Baaij JHF, Weber S, Palygin O, Staruschenko A, Kleta R, Houillier P, Bockenhauer D, Devuyst O, Vargas-Poussou R, Warth R, Zdebik AA, Konrad M. Defects in KCNJ16 Cause a Novel Tubulopathy with Hypokalemia, Salt Wasting, Disturbed Acid-Base Homeostasis, and Sensorineural Deafness. J Am Soc Nephrol 2021; 32:1498-1512. [PMID: 33811157 PMCID: PMC8259640 DOI: 10.1681/asn.2020111587] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/04/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The transepithelial transport of electrolytes, solutes, and water in the kidney is a well-orchestrated process involving numerous membrane transport systems. Basolateral potassium channels in tubular cells not only mediate potassium recycling for proper Na+,K+-ATPase function but are also involved in potassium and pH sensing. Genetic defects in KCNJ10 cause EAST/SeSAME syndrome, characterized by renal salt wasting with hypokalemic alkalosis associated with epilepsy, ataxia, and sensorineural deafness. METHODS A candidate gene approach and whole-exome sequencing determined the underlying genetic defect in eight patients with a novel disease phenotype comprising a hypokalemic tubulopathy with renal salt wasting, disturbed acid-base homeostasis, and sensorineural deafness. Electrophysiologic studies and surface expression experiments investigated the functional consequences of newly identified gene variants. RESULTS We identified mutations in the KCNJ16 gene encoding KCNJ16, which along with KCNJ15 and KCNJ10, constitutes the major basolateral potassium channel of the proximal and distal tubules, respectively. Coexpression of mutant KCNJ16 together with KCNJ15 or KCNJ10 in Xenopus oocytes significantly reduced currents. CONCLUSIONS Biallelic variants in KCNJ16 were identified in patients with a novel disease phenotype comprising a variable proximal and distal tubulopathy associated with deafness. Variants affect the function of heteromeric potassium channels, disturbing proximal tubular bicarbonate handling as well as distal tubular salt reabsorption.
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Affiliation(s)
- Karl P. Schlingmann
- Department of General Pediatrics, Pediatric Nephrology, University Children’s Hospital, Munster, Germany
| | - Aparna Renigunta
- Department of Pediatric Nephrology, Marburg Kidney Research Center, Philipps University, Marburg, Germany
| | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Anna-Lena Forst
- Department of Physiology, Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Vijay Renigunta
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University, Marburg, Germany
| | - Velko Atanasov
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Sinthura Mahendran
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | | | - Valentine Gillion
- Division of Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium
| | - Nathalie Godefroid
- Division of Pediatric Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium
| | - Alice S. Brooks
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Dorien Lugtenberg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jennifer Lake
- Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Huguette Debaix
- Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Christoph Rudin
- Department of Pediatric Nephrology, University Children’s Hospital, Basel, Switzerland
| | - Bertrand Knebelmann
- Department of Nephrology-Transplantation, Assistance Publique Hôpitaux de Paris, Hôpital Necker, Paris, France,Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France
| | - Stephanie Tellier
- Department of Pediatric Nephrology, and Rheumatology, French Reference Center of Rare Renal Diseases (SORARE), CHU Toulouse, Toulouse, France,Division of Rheumatology, Department of Pediatrics, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Caroline Rousset-Rouvière
- Department of Multidisciplinary Pediatrics, Pediatric Nephrology Unit, La Timone, University Hospital of Marseille, Marseille, France
| | - Daan Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H. F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stefanie Weber
- Department of Pediatric Nephrology, Marburg Kidney Research Center, Philipps University, Marburg, Germany
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin,Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, United Kingdom
| | - Pascal Houillier
- Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France,Department of Physiology, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France,Department of Renal Physiology, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, Paris, France
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, United Kingdom
| | - Olivier Devuyst
- Division of Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium,Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France,Department of Renal Physiology, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, Paris, France,Department of Genetics, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France
| | - Richard Warth
- Department of Physiology, Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Anselm A. Zdebik
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom,Department of Renal Medicine, University College London, London, United Kingdom
| | - Martin Konrad
- Department of General Pediatrics, Pediatric Nephrology, University Children’s Hospital, Munster, Germany
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17
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Kortenoeven MLA, Cheng L, Wu Q, Fenton RA. An in vivo protein landscape of the mouse DCT during high dietary K + or low dietary Na + intake. Am J Physiol Renal Physiol 2021; 320:F908-F921. [PMID: 33779313 DOI: 10.1152/ajprenal.00064.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The hormone aldosterone is essential for maintaining K+ and Na+ balance and controlling blood pressure. Aldosterone has different effects if it is secreted due to hypovolemia or hyperkalemia. The kidney distal convoluted tubule (DCT) is believed to play a central role in mediating the differential responses to aldosterone. To determine the alterations in the DCT that may be responsible for these effects, male mice with green fluorescent protein expression specifically in the DCT were maintained on diets containing low NaCl (hypovolemic state) or high potassium citrate (hyperkalemic state) for 4 days, and DCT cells were isolated using fluorescence-activated cell sorting. This pure population of DCT cells was subjected to analysis by liquid chromatography-coupled tandem mass spectrometry. Over 3,000 proteins were identified in the DCT, creating the first proteome of the mouse DCT. Of the identified proteins, 210 proteins were altered in abundance following a low-NaCl diet and 625 proteins following the high-K+ diet. Many of these changes were not detectable by analyzing whole kidney samples from the same animals. When comparing responses to high-K+ versus low-Na+ diets, protein translation, chaperone-mediated protein folding, and protein ubiquitylation were likely to be significantly altered in the DCT subsequent to a high-K+ diet. In conclusion, this study defines an in vivo protein landscape of the DCT in male mice following either a low-NaCl or a high-K+ diet and acts as an essential resource for the kidney research community.NEW & NOTEWORTHY The mineralocorticoid aldosterone, essential for maintaining body K+ and Na+ balance, has different effects if secreted due to hypovolemia or hyperkalemia. Here, we used proteomics to profile kidney distal convoluted tubule (DCT) cells isolated by a novel FACS approach from mice fed a low-Na+ diet (mimicking hypovolemia) or a high-K+ diet (mimicking hyperkalemia). The study provides the first in-depth proteome of the mouse DCT and insights into how it is physiologically regulated.
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Affiliation(s)
- Marleen L A Kortenoeven
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark.,Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Lei Cheng
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Qi Wu
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
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18
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Gripp KW, Smithson SF, Scurr IJ, Baptista J, Majumdar A, Pierre G, Williams M, Henderson LB, Wentzensen IM, McLaughlin H, Leeuwen L, Simon MEH, van Binsbergen E, Dinulos MBP, Kaplan JD, McRae A, Superti-Furga A, Good JM, Kutsche K. Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K + channelopathies. Eur J Hum Genet 2021; 29:1384-1395. [PMID: 33594261 PMCID: PMC8440610 DOI: 10.1038/s41431-021-00818-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/18/2021] [Accepted: 01/22/2021] [Indexed: 12/13/2022] Open
Abstract
Decreased or increased activity of potassium channels caused by loss-of-function and gain-of-function (GOF) variants in the corresponding genes, respectively, underlies a broad spectrum of human disorders affecting the central nervous system, heart, kidney, and other organs. While the association of epilepsy and intellectual disability (ID) with variants affecting function in genes encoding potassium channels is well known, GOF missense variants in K+ channel encoding genes in individuals with syndromic developmental disorders have only recently been recognized. These syndromic phenotypes include Zimmermann–Laband and Temple–Baraitser syndromes, caused by dominant variants in KCNH1, FHEIG syndrome due to dominant variants in KCNK4, and the clinical picture associated with dominant variants in KCNN3. Here we review the presentation of these individuals, including five newly reported with variants in KCNH1 and three additional individuals with KCNN3 variants, all variants likely affecting function. There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis. We suggest to combine the phenotypes and define a new subgroup of potassium channelopathies caused by increased K+ conductance, referred to as syndromic neurodevelopmental K+ channelopathies due to dominant variants in KCNH1, KCNK4, or KCNN3.
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Affiliation(s)
- Karen W Gripp
- Division of Medical Genetics, Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Sarah F Smithson
- Department of Clinical Genetics, University Hospitals Bristol and Weston, Bristol, UK
| | - Ingrid J Scurr
- Department of Clinical Genetics, University Hospitals Bristol and Weston, Bristol, UK
| | - Julia Baptista
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK.,College of Medicine and Health, University of Exeter, Exeter, UK
| | - Anirban Majumdar
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, UK
| | - Germaine Pierre
- Department of Paediatric Metabolic Medicine, Bristol Royal Hospital for Children, Bristol, UK
| | - Maggie Williams
- Bristol Genetics Laboratory, North Bristol NHS Trust, Bristol, UK
| | | | | | | | - Lisette Leeuwen
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Marleen E H Simon
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ellen van Binsbergen
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mary Beth P Dinulos
- Section of Genetics and Child Development, Children's Hospital at Dartmouth, Lebanon, NH, USA
| | - Julie D Kaplan
- Division of Medical Genetics, Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Anne McRae
- Division of Genetics, Birth Defects and Metabolism, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Andrea Superti-Furga
- Division of Genetic Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Jean-Marc Good
- Division of Genetic Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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19
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Manis AD, Palygin O, Isaeva E, Levchenko V, LaViolette PS, Pavlov TS, Hodges MR, Staruschenko A. Kcnj16 knockout produces audiogenic seizures in the Dahl salt-sensitive rat. JCI Insight 2021; 6:143251. [PMID: 33232300 PMCID: PMC7821607 DOI: 10.1172/jci.insight.143251] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/19/2020] [Indexed: 01/08/2023] Open
Abstract
Kir5.1 is an inwardly rectifying potassium (Kir) channel subunit abundantly expressed in the kidney and brain. We previously established the physiologic consequences of a Kcnj16 (gene encoding Kir5.1) knockout in the Dahl salt-sensitive rat (SSKcnj16-/-), which caused electrolyte/pH dysregulation and high-salt diet-induced mortality. Since Kir channel gene mutations may alter neuronal excitability and are linked to human seizure disorders, we hypothesized that SSKcnj16-/- rats would exhibit neurological phenotypes, including increased susceptibility to seizures. SSKcnj16-/- rats exhibited increased light sensitivity (fMRI) and reproducible sound-induced tonic-clonic audiogenic seizures confirmed by electroencephalography. Repeated seizure induction altered behavior, exacerbated hypokalemia, and led to approximately 38% mortality in male SSKcnj16-/- rats. Dietary potassium supplementation did not prevent audiogenic seizures but mitigated hypokalemia and prevented mortality induced by repeated seizures. These results reveal a distinct, nonredundant role for Kir5.1 channels in the brain, introduce a rat model of audiogenic seizures, and suggest that yet-to-be identified mutations in Kcnj16 may cause or contribute to seizure disorders.
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MESH Headings
- Acoustic Stimulation/adverse effects
- Animals
- Disease Models, Animal
- Electroencephalography
- Epilepsy, Reflex/etiology
- Epilepsy, Reflex/genetics
- Epilepsy, Reflex/physiopathology
- Female
- Gene Knockout Techniques
- Humans
- Hypokalemia/etiology
- Hypokalemia/genetics
- Male
- Mutation
- Potassium Channels, Inwardly Rectifying/deficiency
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/physiology
- Potassium, Dietary/administration & dosage
- Rats
- Rats, Inbred Dahl
- Rats, Transgenic
- Seizures/etiology
- Seizures/genetics
- Seizures/physiopathology
- Severity of Illness Index
- Kir5.1 Channel
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Affiliation(s)
| | - Oleg Palygin
- Department of Physiology
- Cardiovascular Center, and
| | | | | | - Peter S. LaViolette
- Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | | | | | - Alexander Staruschenko
- Department of Physiology
- Cardiovascular Center, and
- Clement J. Zablocki VA Medical Center, Milwaukee, Wisconsin, USA
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