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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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Franco-Obregón A, Cambria E, Greutert H, Wernas T, Hitzl W, Egli M, Sekiguchi M, Boos N, Hausmann O, Ferguson SJ, Kobayashi H, Wuertz-Kozak K. TRPC6 in simulated microgravity of intervertebral disc cells. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2018; 27:2621-2630. [PMID: 29968164 DOI: 10.1007/s00586-018-5688-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 06/25/2018] [Indexed: 12/13/2022]
Abstract
PURPOSE Prolonged bed rest and microgravity in space cause intervertebral disc (IVD) degeneration. However, the underlying molecular mechanisms are not completely understood. Transient receptor potential canonical (TRPC) channels are implicated in mechanosensing of several tissues, but are poorly explored in IVDs. METHODS Primary human IVD cells from surgical biopsies composed of both annulus fibrosus and nucleus pulposus (passage 1-2) were exposed to simulated microgravity and to the TRPC channel inhibitor SKF-96365 (SKF) for up to 5 days. Proliferative capacity, cell cycle distribution, senescence and TRPC channel expression were analyzed. RESULTS Both simulated microgravity and TRPC channel antagonism reduced the proliferative capacity of IVD cells and induced senescence. While significant changes in cell cycle distributions (reduction in G1 and accumulation in G2/M) were observed upon SKF treatment, the effect was small upon 3 days of simulated microgravity. Finally, downregulation of TRPC6 was shown under simulated microgravity. CONCLUSIONS Simulated microgravity and TRPC channel inhibition both led to reduced proliferation and increased senescence. Furthermore, simulated microgravity reduced TRPC6 expression. IVD cell senescence and mechanotransduction may hence potentially be regulated by TRPC6 expression. This study thus reveals promising targets for future studies. These slides can be retrieved under Electronic Supplementary Material.
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Affiliation(s)
- Alfredo Franco-Obregón
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- BioIonic Currents Electromagnetic Pulsing Systems Laboratory, BICEPS, National University of Singapore, Singapore, Singapore
| | - Elena Cambria
- Institute for Biomechanics, D-HEST, ETH Zurich, Hönggerbergring 64, 8093, Zurich, Switzerland
| | - Helen Greutert
- Institute for Biomechanics, D-HEST, ETH Zurich, Hönggerbergring 64, 8093, Zurich, Switzerland
| | - Timon Wernas
- School of Engineering and Architecture, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Wolfgang Hitzl
- Research Office (Biostatistics), Paracelsus Private Medical University, Salzburg, Austria
- Department of Ophthalmology and Optometry, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Marcel Egli
- School of Engineering and Architecture, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Miho Sekiguchi
- Department of Orthopaedic Surgery, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Norbert Boos
- Prodorso Center for Spinal Medicine, Zurich, Switzerland
| | - Oliver Hausmann
- Neuro- and Spine Center, Hirslanden Klinik St. Anna, Lucerne, Switzerland
| | - Stephen J Ferguson
- Institute for Biomechanics, D-HEST, ETH Zurich, Hönggerbergring 64, 8093, Zurich, Switzerland
| | - Hiroshi Kobayashi
- Institute for Biomechanics, D-HEST, ETH Zurich, Hönggerbergring 64, 8093, Zurich, Switzerland
- Department of Orthopaedic Surgery, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Karin Wuertz-Kozak
- Institute for Biomechanics, D-HEST, ETH Zurich, Hönggerbergring 64, 8093, Zurich, Switzerland.
- Spine Center, Schön Klinik München Harlaching, 81547, Munich, Germany.
- Academic Teaching Hospital and Spine Research Institute, Paracelsus Private Medical University, Salzburg, Austria.
- Department of Health Science, University of Potsdam, Potsdam, Germany.
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Cheng H, James AF, Boyett MR, Hancox JC. Cardiac background sodium current: Elusive but important. Channels (Austin) 2017; 11:3-4. [PMID: 27367468 DOI: 10.1080/19336950.2016.1207476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Hongwei Cheng
- a School of Physiology, Pharmacology & Neuroscience, University of Bristol , Bristol , UK
| | - Andrew F James
- a School of Physiology, Pharmacology & Neuroscience, University of Bristol , Bristol , UK
| | - Mark R Boyett
- b Institute of Cardiovascular Sciences, University of Manchester, Core Technology Facility , Manchester , UK
| | - Jules C Hancox
- a School of Physiology, Pharmacology & Neuroscience, University of Bristol , Bristol , UK
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Cheng H, Curtis AE, Fellingham C, Hancox JC. Multiple ion channel block by the cation channel inhibitor SKF-96365 in myocytes from the rabbit atrioventricular node. Physiol Rep 2016; 4:4/11/e12819. [PMID: 27288059 PMCID: PMC4908495 DOI: 10.14814/phy2.12819] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 05/12/2016] [Indexed: 12/31/2022] Open
Abstract
The atrioventricular node (AVN) of the cardiac conduction system coordinates atrial-ventricular excitation and can act as a subsidiary pacemaker. Recent evidence suggests that an inward background sodium current, IB,Na, carried by nonselective cation channels (NSCCs), contributes to AVN cell pacemaking. The study of the physiological contribution of IB,Na has been hampered, however, by a lack of selective pharmacological antagonists. This study investigated effects of the NSCC inhibitor SKF-96365 on spontaneous activity, IB,Na, and other ionic currents in AVN cells isolated from the rabbit. Whole-cell patch-clamp recordings of action potentials (APs) and ionic currents were made at 35-37°C. A concentration of 10 μmol/L SKF-96365 slowed spontaneous action potential rate by 13.9 ± 5.3% (n = 8) and slope of the diastolic depolarization from 158.1 ± 30.5 to 86.8 ± 30.5 mV sec(-1) (P < 0.01; n = 8). Action potential upstroke velocity and maximum diastolic potential were also reduced. Under IB,Na-selective conditions, 10 μmol/L SKF-96365 inhibited IB,Na at -50 mV by 36.1 ± 6.8% (n = 8); however, effects on additional channel currents were also observed. Thus, the peak l-type calcium current (ICa,L) at +10 mV was inhibited by 38.6 ± 8.1% (n = 8), while the rapid delayed rectifier current, IKr, tails at -40 mV following depolarization to +20 mV were inhibited by 55.6 ± 4.6% (n = 8). The hyperpolarization-activated current, If, was unaffected by SKF-96365. Collectively, these results indicate that SKF-96365 exerts a moderate inhibitory effect on IB,Na and slows AVN cell pacemaking. However, additional effects of the compound on ICa,L and IKr confound the use of SKF-96365 to dissect out selectively the physiological role of IB,Na in the AVN.
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Affiliation(s)
- Hongwei Cheng
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and Neuroscience University of Bristol, Bristol, UK
| | - Alexander E Curtis
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and Neuroscience University of Bristol, Bristol, UK
| | - Claire Fellingham
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and Neuroscience University of Bristol, Bristol, UK
| | - Jules C Hancox
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and Neuroscience University of Bristol, Bristol, UK
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