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Naveed M, Mohammed ASA, Topal L, Kovács ZM, Dienes C, Ovári J, Szentandrássy N, Magyar J, Bányász T, Prorok J, Jost N, Virág L, Baczkó I, Varró A, Nánási PP, Horváth B. Selective Inhibition of Cardiac Late Na + Current Is Based on Fast Offset Kinetics of the Inhibitor. Biomedicines 2023; 11:2383. [PMID: 37760824 PMCID: PMC10525890 DOI: 10.3390/biomedicines11092383] [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: 07/23/2023] [Revised: 08/11/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
The present study was designed to test the hypothesis that the selectivity of blocking the late Na+ current (INaL) over the peak Na+ current (INaP) is related to the fast offset kinetics of the Na+ channel inhibitor. Therefore, the effects of 1 µM GS967 (INaL inhibitor), 20 µM mexiletine (I/B antiarrhythmic) and 10 µM quinidine (I/A antiarrhythmic) on INaL and INaP were compared in canine ventricular myocardium. INaP was estimated as the maximum velocity of action potential upstroke (V+max). Equal amounts of INaL were dissected by the applied drug concentrations under APVC conditions. The inhibition of INaL by mexiletine and quinidine was comparable under a conventional voltage clamp, while both were smaller than the inhibitory effect of GS967. Under steady-state conditions, the V+max block at the physiological cycle length of 700 ms was 2.3% for GS967, 11.4% for mexiletine and 26.2% for quinidine. The respective offset time constants were 110 ± 6 ms, 456 ± 284 ms and 7.2 ± 0.9 s. These results reveal an inverse relationship between the offset time constant and the selectivity of INaL over INaP inhibition without any influence of the onset rate constant. It is concluded that the selective inhibition of INaL over INaP is related to the fast offset kinetics of the Na+ channel inhibitor.
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Affiliation(s)
- Muhammad Naveed
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (M.N.); (A.S.A.M.); (L.T.); (N.J.); (L.V.); (I.B.); (A.V.)
| | - Aiman Saleh A. Mohammed
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (M.N.); (A.S.A.M.); (L.T.); (N.J.); (L.V.); (I.B.); (A.V.)
| | - Leila Topal
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (M.N.); (A.S.A.M.); (L.T.); (N.J.); (L.V.); (I.B.); (A.V.)
| | - Zsigmond Máté Kovács
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
| | - Csaba Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
| | - József Ovári
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, H-6720 Debrecen, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
- Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
| | - János Prorok
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Loránd Eötvös Research Network, 1097 Szeged, Hungary;
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (M.N.); (A.S.A.M.); (L.T.); (N.J.); (L.V.); (I.B.); (A.V.)
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Loránd Eötvös Research Network, 1097 Szeged, Hungary;
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (M.N.); (A.S.A.M.); (L.T.); (N.J.); (L.V.); (I.B.); (A.V.)
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (M.N.); (A.S.A.M.); (L.T.); (N.J.); (L.V.); (I.B.); (A.V.)
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (M.N.); (A.S.A.M.); (L.T.); (N.J.); (L.V.); (I.B.); (A.V.)
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Loránd Eötvös Research Network, 1097 Szeged, Hungary;
| | - Péter P. Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
- Division of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, H-6720 Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-6720 Debrecen, Hungary; (Z.M.K.); (C.D.); (J.O.); (N.S.); (J.M.); (T.B.); (B.H.)
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Proost VM, van den Berg MP, Remme CA, Wilde AAM. SCN5A-1795insD founder variant: a unique Dutch experience spanning 7 decades. Neth Heart J 2023:10.1007/s12471-023-01799-8. [PMID: 37474841 PMCID: PMC10400486 DOI: 10.1007/s12471-023-01799-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2023] [Indexed: 07/22/2023] Open
Abstract
The SCN5A-1795insD founder variant is a unique SCN5A gene variant found in a large Dutch pedigree that first came to attention in the late 1950s. To date, this is still one of the largest and best described SCN5A founder families worldwide. It was the first time that a single pathogenic variant in SCN5A proved to be sufficient to cause a sodium channel overlap syndrome. Affected family members displayed features of Brugada syndrome, cardiac conduction disease and long QT syndrome type 3, thus encompassing features of both loss and gain of sodium channel function. This brief summary takes us past 70 years of clinical experience and over 2 decades of research. It is remarkable to what extent researchers and clinicians have managed to gain understanding of this complex phenotype in a relatively short time. Extensive clinical, genetic, electrophysiological and molecular studies have provided fundamental insights into SCN5A and the cardiac sodium channel Nav1.5.
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Affiliation(s)
- Virginnio M Proost
- Department of Clinical Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam University Medical Centres, location Academic Medical Centre/University of Amsterdam, Amsterdam, The Netherlands
| | - Maarten P van den Berg
- Department of Cardiology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam University Medical Centres, location Academic Medical Centre/University of Amsterdam, Amsterdam, The Netherlands
| | - Arthur A M Wilde
- Department of Clinical Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam University Medical Centres, location Academic Medical Centre/University of Amsterdam, Amsterdam, The Netherlands.
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Pliushcheuskaya P, Künze G. Recent Advances in Computer-Aided Structure-Based Drug Design on Ion Channels. Int J Mol Sci 2023; 24:ijms24119226. [PMID: 37298178 DOI: 10.3390/ijms24119226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Ion channels play important roles in fundamental biological processes, such as electric signaling in cells, muscle contraction, hormone secretion, and regulation of the immune response. Targeting ion channels with drugs represents a treatment option for neurological and cardiovascular diseases, muscular degradation disorders, and pathologies related to disturbed pain sensation. While there are more than 300 different ion channels in the human organism, drugs have been developed only for some of them and currently available drugs lack selectivity. Computational approaches are an indispensable tool for drug discovery and can speed up, especially, the early development stages of lead identification and optimization. The number of molecular structures of ion channels has considerably increased over the last ten years, providing new opportunities for structure-based drug development. This review summarizes important knowledge about ion channel classification, structure, mechanisms, and pathology with the main focus on recent developments in the field of computer-aided, structure-based drug design on ion channels. We highlight studies that link structural data with modeling and chemoinformatic approaches for the identification and characterization of new molecules targeting ion channels. These approaches hold great potential to advance research on ion channel drugs in the future.
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Affiliation(s)
- Palina Pliushcheuskaya
- Institute for Drug Discovery, Medical Faculty, University of Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany
| | - Georg Künze
- Institute for Drug Discovery, Medical Faculty, University of Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstr. 16-18, D-04107 Leipzig, Germany
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Ghovanloo MR, Tyagi S, Zhao P, Kiziltug E, Estacion M, Dib-Hajj SD, Waxman SG. High-throughput combined voltage-clamp/current-clamp analysis of freshly isolated neurons. CELL REPORTS METHODS 2023; 3:100385. [PMID: 36814833 PMCID: PMC9939380 DOI: 10.1016/j.crmeth.2022.100385] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/11/2022] [Accepted: 12/15/2022] [Indexed: 01/15/2023]
Abstract
The patch-clamp technique is the gold-standard methodology for analysis of excitable cells. However, throughput of manual patch-clamp is slow, and high-throughput robotic patch-clamp, while helpful for applications like drug screening, has been primarily used to study channels and receptors expressed in heterologous systems. We introduce an approach for automated high-throughput patch-clamping that enhances analysis of excitable cells at the channel and cellular levels. This involves dissociating and isolating neurons from intact tissues and patch-clamping using a robotic instrument, followed by using an open-source Python script for analysis and filtration. As a proof of concept, we apply this approach to investigate the biophysical properties of voltage-gated sodium (Nav) channels in dorsal root ganglion (DRG) neurons, which are among the most diverse and complex neuronal cells. Our approach enables voltage- and current-clamp recordings in the same cell, allowing unbiased, fast, simultaneous, and head-to-head electrophysiological recordings from a wide range of freshly isolated neurons without requiring culturing on coverslips.
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Affiliation(s)
- Mohammad-Reza Ghovanloo
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA
- Neuro-Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Sidharth Tyagi
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA
- Neuro-Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
- Medical Scientist Training Program, Yale University School of Medicine, New Haven, CT, USA
| | - Peng Zhao
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA
- Neuro-Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Emre Kiziltug
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Mark Estacion
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA
- Neuro-Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Sulayman D. Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA
- Neuro-Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Stephen G. Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA
- Neuro-Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
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Dzhumaniiazova I, Vornanen M, Pustovit OB, Voronkov YI, Abramochkin DV. Effects of Tetrodotoxin and Ranolazine on the Late INa of Zebrafish Ventricular Myocytes. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022070031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Abdelsayed M, Page D, Ruben PC. ARumenamides: A novel class of potential antiarrhythmic compounds. Front Pharmacol 2022; 13:976903. [PMID: 36249789 PMCID: PMC9554508 DOI: 10.3389/fphar.2022.976903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Most therapeutics targeting cardiac voltage-gated sodium channels (Nav1.5) attenuate the sodium current (INa) conducted through the pore of the protein. Whereas these drugs may be beneficial for disease states associated with gain-of-function (GoF) in Nav1.5, few attempts have been made to therapeutically treat loss-of-function (LoF) conditions. The primary impediment to designing efficacious therapies for LoF is a tendency for drugs to occlude the Nav1.5 central pore. We hypothesized that molecular candidates with a high affinity for the fenestrations would potentially reduce pore block.Methods and Results: Virtual docking was performed on 21 compounds, selected based on their affinity for the fenestrations in Nav1.5, which included a class of sulfonamides and carboxamides we identify as ARumenamide (AR). Six ARs, AR-051, AR-189, AR-674, AR-802, AR-807 and AR-811, were further docked against Nav1.5 built on NavAb and rNav1.5. Based on the virtual docking results, these particular ARs have a high affinity for Domain III-IV and Domain VI-I fenestrations. Upon functional characterization, a trend was observed in the effects of the six ARs on INa. An inverse correlation was established between the aromaticity of the AR’s functional moieties and compound block. Due to its aromaticity, AR-811 blocked INa the least compared with other aromatic ARs, which also decelerated fast inactivation onset. AR-674, with its aliphatic functional group, significantly suppresses INa and enhances use-dependence in Nav1.5. AR-802 and AR-811, in particular, decelerated fast inactivation kinetics in the most common Brugada Syndrome Type 1 and Long-QT Syndrome Type 3 mutant, E1784K, without affecting peak or persistent INa.Conclusion: Our hypothesis that LoF in Nav1.5 may be therapeutically treated was supported by the discovery of ARs, which appear to preferentially block the fenestrations. ARs with aromatic functional groups as opposed to aliphatic groups efficaciously maintained Nav1.5 availability. We predict that these bulkier side groups may have a higher affinity for the hydrophobic milieu of the fenestrations, remaining there rather than in the central pore of the channel. Future refinements of AR compound structures and additional validation by molecular dynamic simulations and screening against more Brugada variants will further support their potential benefits in treating certain LoF cardiac arrhythmias.
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Affiliation(s)
- Mena Abdelsayed
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, United States
- Department of Medicine, Stanford University, Stanford, CA, United States
- *Correspondence: Mena Abdelsayed, ; Peter C. Ruben,
| | - Dana Page
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Peter C. Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- *Correspondence: Mena Abdelsayed, ; Peter C. Ruben,
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Govorunova EG, Sineshchekov OA, Brown LS, Spudich JL. Biophysical characterization of light-gated ion channels using planar automated patch clamp. Front Mol Neurosci 2022; 15:976910. [PMID: 36017077 PMCID: PMC9396214 DOI: 10.3389/fnmol.2022.976910] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 07/21/2022] [Indexed: 01/09/2023] Open
Abstract
Channelrhodopsins (ChRs) are proteins that guide phototaxis in protists and exhibit light-gated channel conductance when their genes are heterologously expressed in mammalian cells. ChRs are widely used as molecular tools to control neurons and cardiomyocytes with light (optogenetics). Cation- and anion-selective ChRs (CCRs and ACRs, respectively) enable stimulation and inhibition of neuronal activity by depolarization and hyperpolarization of the membrane, respectively. More than 400 natural ChR variants have been identified so far, and high-throughput polynucleotide sequencing projects add many more each year. However, electrophysiological characterization of new ChRs lags behind because it is mostly done by time-consuming manual patch clamp (MPC). Here we report using a high-throughput automated patch clamp (APC) platform, SyncroPatch 384i from Nanion Technologies, for ChR research. We find that this instrument can be used for determination of the light intensity dependence and current-voltage relationships in ChRs and discuss its advantages and limitations.
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Affiliation(s)
- Elena G. Govorunova
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, United States
| | - Oleg A. Sineshchekov
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, United States
| | - Leonid S. Brown
- Biophysics Interdepartmental Group, Department of Physics, University of Guelph, Guelph, ON, Canada
| | - John L. Spudich
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, United States
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Rosholm KR, Badone B, Karatsiompani S, Nagy D, Seibertz F, Voigt N, Bell DC. Adventures and Advances in Time Travel With Induced Pluripotent Stem Cells and Automated Patch Clamp. Front Mol Neurosci 2022; 15:898717. [PMID: 35813069 PMCID: PMC9258620 DOI: 10.3389/fnmol.2022.898717] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/13/2022] [Indexed: 01/21/2023] Open
Abstract
In the Hollywood blockbuster “The Curious Case of Benjamin Button” a fantastical fable unfolds of a man’s life that travels through time reversing the aging process; as the tale progresses, the frail old man becomes a vigorous, vivacious young man, then man becomes boy and boy becomes baby. The reality of cellular time travel, however, is far more wondrous: we now have the ability to both reverse and then forward time on mature cells. Four proteins were found to rewind the molecular clock of adult cells back to their embryonic, “blank canvas” pluripotent stem cell state, allowing these pluripotent stem cells to then be differentiated to fast forward their molecular clocks to the desired adult specialist cell types. These four proteins – the “Yamanaka factors” – form critical elements of this cellular time travel, which deservedly won Shinya Yamanaka the Nobel Prize for his lab’s work discovering them. Human induced pluripotent stem cells (hiPSCs) hold much promise in our understanding of physiology and medicine. They encapsulate the signaling pathways of the desired cell types, such as cardiomyocytes or neurons, and thus act as model cells for defining the critical ion channel activity in healthy and disease states. Since hiPSCs can be derived from any patient, highly specific, personalized (or stratified) physiology, and/or pathophysiology can be defined, leading to exciting developments in personalized medicines and interventions. As such, hiPSC married with high throughput automated patch clamp (APC) ion channel recording platforms provide a foundation for significant physiological, medical and drug discovery advances. This review aims to summarize the current state of affairs of hiPSC and APC: the background and recent advances made; and the pros, cons and challenges of these technologies. Whilst the authors have yet to finalize a fully functional time traveling machine, they will endeavor to provide plausible future projections on where hiPSC and APC are likely to carry us. One future projection the authors are confident in making is the increasing necessity and adoption of these technologies in the discovery of the next blockbuster, this time a life-enhancing ion channel drug, not a fantastical movie.
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Affiliation(s)
- Kadla R. Rosholm
- Sophion Bioscience A/S, Ballerup, Denmark
- *Correspondence: Kadla R. Rosholm,
| | | | | | - David Nagy
- Sophion Bioscience Inc., Woburn, MA, United States
| | - Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Göttingen, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
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Fouda MA, Ghovanloo MR, Ruben PC. Late sodium current: incomplete inactivation triggers seizures, myotonias, arrhythmias, and pain syndromes. J Physiol 2022; 600:2835-2851. [PMID: 35436004 DOI: 10.1113/jp282768] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
Acquired and inherited dysfunction in voltage-gated sodium channels underlies a wide range of diseases. "In addition to the defects in trafficking and expression, sodium channelopathies are also caused by dysfunction in one or several gating properties, for instance activation or inactivation. Disruption of the channel inactivation leads to the increased late sodium current, which is a common defect in seizure disorders, cardiac arrhythmias skeletal muscle myotonia and pain. An increase in late sodium current leads to repetitive action potential in neurons and skeletal muscles, and prolonged action potential duration in the heart. In this topical review, we compare the effects of late sodium current in brain, heart, skeletal muscle, and peripheral nerves. Abstract figure legend Shows cartoon illustration of general Nav channel transitions between (1) resting, (2) open, and (3) fast inactivated states. Disruption of the inactivation process exacerbates (4) late sodium currents. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mohamed A Fouda
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.,Department of Pharmacology and Toxicology, Alexandria University, Alexandria, Egypt
| | | | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
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10
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Horváth B, Szentandrássy N, Dienes C, Kovács ZM, Nánási PP, Chen-Izu Y, Izu LT, Banyasz T. Exploring the Coordination of Cardiac Ion Channels With Action Potential Clamp Technique. Front Physiol 2022; 13:864002. [PMID: 35370800 PMCID: PMC8966222 DOI: 10.3389/fphys.2022.864002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 02/15/2022] [Indexed: 11/30/2022] Open
Abstract
The patch clamp technique underwent continual advancement and developed numerous variants in cardiac electrophysiology since its introduction in the late 1970s. In the beginning, the capability of the technique was limited to recording one single current from one cell stimulated with a rectangular command pulse. Since that time, the technique has been extended to record multiple currents under various command pulses including action potential. The current review summarizes the development of the patch clamp technique in cardiac electrophysiology with special focus on the potential applications in integrative physiology.
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Affiliation(s)
- Balázs Horváth
- Department of Physiology, University of Debrecen, Debrecen, Hungary
| | - Norbert Szentandrássy
- Department of Physiology, University of Debrecen, Debrecen, Hungary
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - Csaba Dienes
- Department of Physiology, University of Debrecen, Debrecen, Hungary
| | | | - Péter P. Nánási
- Department of Physiology, University of Debrecen, Debrecen, Hungary
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - Ye Chen-Izu
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Leighton T. Izu
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Tamas Banyasz
- Department of Physiology, University of Debrecen, Debrecen, Hungary
- *Correspondence: Tamas Banyasz,
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Johnson JP, Focken T, Khakh K, Tari PK, Dube C, Goodchild SJ, Andrez JC, Bankar G, Bogucki D, Burford K, Chang E, Chowdhury S, Dean R, de Boer G, Decker S, Dehnhardt C, Feng M, Gong W, Grimwood M, Hasan A, Hussainkhel A, Jia Q, Lee S, Li J, Lin S, Lindgren A, Lofstrand V, Mezeyova J, Namdari R, Nelkenbrecher K, Shuart NG, Sojo L, Sun S, Taron M, Waldbrook M, Weeratunge D, Wesolowski S, Williams A, Wilson M, Xie Z, Yoo R, Young C, Zenova A, Zhang W, Cutts AJ, Sherrington RP, Pimstone SN, Winquist R, Cohen CJ, Empfield JR. NBI-921352, a first-in-class, Na V1.6 selective, sodium channel inhibitor that prevents seizures in Scn8a gain-of-function mice, and wild-type mice and rats. eLife 2022; 11:72468. [PMID: 35234610 PMCID: PMC8903829 DOI: 10.7554/elife.72468] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
NBI-921352 (formerly XEN901) is a novel sodium channel inhibitor designed to specifically target NaV1.6 channels. Such a molecule provides a precision-medicine approach to target SCN8A-related epilepsy syndromes (SCN8A-RES), where gain-of-function (GoF) mutations lead to excess NaV1.6 sodium current, or other indications where NaV1.6 mediated hyper-excitability contributes to disease (Gardella and Møller, 2019; Johannesen et al., 2019; Veeramah et al., 2012). NBI-921352 is a potent inhibitor of NaV1.6 (IC500.051 µM), with exquisite selectivity over other sodium channel isoforms (selectivity ratios of 756 X for NaV1.1, 134 X for NaV1.2, 276 X for NaV1.7, and >583 Xfor NaV1.3, NaV1.4, and NaV1.5). NBI-921352is a state-dependent inhibitor, preferentially inhibiting inactivatedchannels. The state dependence leads to potent stabilization of inactivation, inhibiting NaV1.6 currents, including resurgent and persistent NaV1.6 currents, while sparing the closed/rested channels. The isoform-selective profile of NBI-921352 led to a robust inhibition of action-potential firing in glutamatergic excitatory pyramidal neurons, while sparing fast-spiking inhibitory interneurons, where NaV1.1 predominates. Oral administration of NBI-921352 prevented electrically induced seizures in a Scn8a GoF mouse,as well as in wild-type mouse and ratseizure models. NBI-921352 was effective in preventing seizures at lower brain and plasma concentrations than commonly prescribed sodium channel inhibitor anti-seizure medicines (ASMs) carbamazepine, phenytoin, and lacosamide. NBI-921352 waswell tolerated at higher multiples of the effective plasma and brain concentrations than those ASMs. NBI-921352 is entering phase II proof-of-concept trials for the treatment of SCN8A-developmental epileptic encephalopathy (SCN8A-DEE) and adult focal-onset seizures.
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Affiliation(s)
- J P Johnson
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Thilo Focken
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Kuldip Khakh
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Celine Dube
- In Vivo Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | | | - Girish Bankar
- In Vivo Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - David Bogucki
- Chemistry, Medipure Pharmaceuticals, Burnaby BC, Canada
| | | | - Elaine Chang
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Richard Dean
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Gina de Boer
- Compound Properties, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Shannon Decker
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Mandy Feng
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Wei Gong
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Abid Hasan
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Qi Jia
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Stephanie Lee
- Compound Properties, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Jenny Li
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Sophia Lin
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Andrea Lindgren
- Compound Properties, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Janette Mezeyova
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Rostam Namdari
- Translational Drug Development, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | | | - Luis Sojo
- Compound Properties, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Shaoyi Sun
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Matthew Taron
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Diana Weeratunge
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | - Aaron Williams
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Michael Wilson
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Zhiwei Xie
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Rhena Yoo
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Clint Young
- In Vitro Biology, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Alla Zenova
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Wei Zhang
- Chemistry, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | - Alison J Cutts
- Scientific Affairs, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
| | | | | | | | - Charles J Cohen
- Executive Team, Xenon Pharmaceuticals, Inc., Burnaby BC, Canada
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12
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Obergrussberger A, Rinke-Weiß I, Goetze TA, Rapedius M, Brinkwirth N, Becker N, Rotordam MG, Hutchison L, Madau P, Pau D, Dalrymple D, Braun N, Friis S, Pless SA, Fertig N. The suitability of high throughput automated patch clamp for physiological applications. J Physiol 2021; 600:277-297. [PMID: 34555195 DOI: 10.1113/jp282107] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/16/2021] [Indexed: 01/18/2023] Open
Abstract
Although automated patch clamp (APC) devices have been around for many years and have become an integral part of many aspects of drug discovery, high throughput instruments with gigaohm seal data quality are relatively new. Experiments where a large number of compounds are screened against ion channels are ideally suited to high throughput APC, particularly when the amount of compound available is low. Here we evaluate different APC approaches using a variety of ion channels and screening settings. We have performed a screen of 1920 compounds on GluN1/GluN2A NMDA receptors for negative allosteric modulation using both the SyncroPatch 384 and FLIPR. Additionally, we tested the effect of 36 arthropod venoms on NaV 1.9 using a single 384-well plate on the SyncroPatch 384. As an example for mutant screening, a range of acid-sensing ion channel variants were tested and the success rate increased through fluorescence-activated cell sorting (FACS) prior to APC experiments. Gigaohm seal data quality makes the 384-format accessible to recording of primary and stem cell-derived cells on the SyncroPatch 384. We show recordings in voltage and current clamp modes of stem cell-derived cardiomyocytes. In addition, the option of intracellular solution exchange enabled investigations into the effects of intracellular Ca2+ and cAMP on TRPC5 and HCN2 currents, respectively. Together, these data highlight the broad applicability and versatility of APC platforms and also outlines some limitations of the approach. KEY POINTS: High throughput automated patch clamp (APC) can be used for a variety of applications involving ion channels. Lower false positive rates were achieved using automated patch clamp versus a fluorometric imaging plate reader (FLIPR) in a high throughput compound screen against NMDA receptors. Genetic variants and mutations can be screened on a single 384-well plate to reduce variability of experimental parameters. Intracellular solution can be perfused to investigate effects of ions and second messenger systems without the need for excised patches. Primary cells and stem cell-derived cells can be used on high throughput APC with reasonable success rates for cell capture, voltage clamp measurements and action potential recordings in current clamp mode.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Nina Braun
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
| | | | - Stephan A Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
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13
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Al Sayed ZR, Jouni M, Gourraud JB, Belbachir N, Barc J, Girardeau A, Forest V, Derevier A, Gaignerie A, Chariau C, Cimarosti B, Canac R, Olchesqui P, Charpentier E, Schott JJ, Redon R, Baró I, Probst V, Charpentier F, Loussouarn G, Zibara K, Lamirault G, Lemarchand P, Gaborit N. A consistent arrhythmogenic trait in Brugada syndrome cellular phenotype. Clin Transl Med 2021; 11:e413. [PMID: 34185406 PMCID: PMC8181201 DOI: 10.1002/ctm2.413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/14/2021] [Accepted: 04/21/2021] [Indexed: 02/05/2023] Open
Affiliation(s)
| | - Mariam Jouni
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France
| | - Jean-Baptiste Gourraud
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France.,l'institut du thorax, CHU Nantes, Nantes, France
| | | | - Julien Barc
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France
| | | | - Virginie Forest
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France
| | - Aude Derevier
- Nantes Université, CHU Nantes, Inserm, CNRS, SFR Santé, Nantes, France
| | - Anne Gaignerie
- Nantes Université, CHU Nantes, Inserm, CNRS, SFR Santé, Nantes, France
| | - Caroline Chariau
- Nantes Université, CHU Nantes, Inserm, CNRS, SFR Santé, Nantes, France
| | | | - Robin Canac
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France
| | | | | | - Jean-Jacques Schott
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France.,l'institut du thorax, CHU Nantes, Nantes, France
| | - Richard Redon
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France.,l'institut du thorax, CHU Nantes, Nantes, France
| | - Isabelle Baró
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France
| | - Vincent Probst
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France.,l'institut du thorax, CHU Nantes, Nantes, France
| | - Flavien Charpentier
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France.,l'institut du thorax, CHU Nantes, Nantes, France
| | | | - Kazem Zibara
- Laboratory of Stem Cells, PRASE, Biology Department, Faculty of Sciences, Lebanese University, Beirut, Lebanon
| | - Guillaume Lamirault
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France.,l'institut du thorax, CHU Nantes, Nantes, France
| | - Patricia Lemarchand
- l'institut du thorax, Inserm, CNRS, UNIV Nantes, Nantes, France.,l'institut du thorax, CHU Nantes, Nantes, France
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14
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Hézső T, Naveed M, Dienes C, Kiss D, Prorok J, Árpádffy-Lovas T, Varga R, Fujii E, Mercan T, Topal L, Kistamás K, Szentandrássy N, Almássy J, Jost N, Magyar J, Bányász T, Baczkó I, Varró A, Nánási PP, Virág L, Horváth B. Mexiletine-like cellular electrophysiological effects of GS967 in canine ventricular myocardium. Sci Rep 2021; 11:9565. [PMID: 33953276 PMCID: PMC8100105 DOI: 10.1038/s41598-021-88903-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/26/2021] [Indexed: 12/14/2022] Open
Abstract
Enhancement of the late Na+ current (INaL) increases arrhythmia propensity in the heart, while suppression of the current is antiarrhythmic. GS967 is an agent considered as a selective blocker of INaL. In the present study, effects of GS967 on INaL and action potential (AP) morphology were studied in canine ventricular myocytes by using conventional voltage clamp, action potential voltage clamp and sharp microelectrode techniques. The effects of GS967 (1 µM) were compared to those of the class I/B antiarrhythmic compound mexiletine (40 µM). Under conventional voltage clamp conditions, INaL was significantly suppressed by GS967 and mexiletine, causing 80.4 ± 2.2% and 59.1 ± 1.8% reduction of the densities of INaL measured at 50 ms of depolarization, and 79.0 ± 3.1% and 63.3 ± 2.7% reduction of the corresponding current integrals, respectively. Both drugs shifted the voltage dependence of the steady-state inactivation curve of INaL towards negative potentials. GS967 and mexiletine dissected inward INaL profiles under AP voltage clamp conditions having densities, measured at 50% of AP duration (APD), of −0.37 ± 0.07 and −0.28 ± 0.03 A/F, and current integrals of −56.7 ± 9.1 and −46.6 ± 5.5 mC/F, respectively. Drug effects on peak Na+ current (INaP) were assessed by recording the maximum velocity of AP upstroke (V+max) in multicellular preparations. The offset time constant was threefold faster for GS967 than mexiletine (110 ms versus 289 ms), while the onset of the rate-dependent block was slower in the case of GS967. Effects on beat-to-beat variability of APD was studied in isolated myocytes. Beat-to-beat variability was significantly decreased by both GS967 and mexiletine (reduction of 42.1 ± 6.5% and 24.6 ± 12.8%, respectively) while their shortening effect on APD was comparable. It is concluded that the electrophysiological effects of GS967 are similar to those of mexiletine, but with somewhat faster offset kinetics of V+max block. However, since GS967 depressed V+max and INaL at the same concentration, the current view that GS967 represents a new class of drugs that selectively block INaL has to be questioned and it is suggested that GS967 should be classified as a class I/B antiarrhythmic agent.
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Affiliation(s)
- Tamás Hézső
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Muhammad Naveed
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Csaba Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Dénes Kiss
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - János Prorok
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Tamás Árpádffy-Lovas
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Richárd Varga
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Erika Fujii
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Tanju Mercan
- Department of Biophysics, School of Medicine, Akdeniz University, Antalya, Turkey
| | - Leila Topal
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary.,Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - János Almássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary.,Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary. .,MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary. .,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary. .,Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary.
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary.,Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
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15
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Functional evaluation of human ion channel variants using automated electrophysiology. Methods Enzymol 2021; 654:383-405. [PMID: 34120723 DOI: 10.1016/bs.mie.2021.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Patch clamp recording enabled a revolution in cellular electrophysiology, and is useful for evaluating the functional consequences of ion channel gene mutations or variants associated with human disorders called channelopathies. However, due to massive growth of genetic testing in medical practice and research, the number of known ion channel variants has exploded into the thousands. Fortunately, automated methods for performing patch clamp recording have emerged as important tools to address the explosion in ion channel variants. In this chapter, we present our approach to harnessing automated electrophysiology to study a human voltage-gated potassium channel gene (KCNQ1), which harbors hundreds of mutations associated with genetic disorders of heart rhythm including the congenital long-QT syndrome. We include protocols for performing high efficiency electroporation of heterologous cells with recombinant KCNQ1 plasmid DNA and for automated planar patch recording including data analysis. These methods can be adapted for studying other voltage-gated ion channels.
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