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Schneider A, Hage A, Stein ICAP, Kriedemann N, Zweigerdt R, Leffler A. A Possible Role of Tetrodotoxin-Sensitive Na + Channels for Oxidation-Induced Late Na + Currents in Cardiomyocytes. Int J Mol Sci 2024; 25:6596. [PMID: 38928302 PMCID: PMC11203718 DOI: 10.3390/ijms25126596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
An accumulation of reactive oxygen species (ROS) in cardiomyocytes can induce pro-arrhythmogenic late Na+ currents by removing the inactivation of voltage-gated Na+ channels including the tetrodotoxin (TTX)-resistant cardiac α-subunit Nav1.5 as well as TTX-sensitive α-subunits like Nav1.2 and Nav1.3. Here, we explored oxidant-induced late Na+ currents in mouse cardiomyocytes and human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as well as in HEK 293 cells expressing Nav1.2, Nav1.3, or Nav1.5. Na+ currents in mouse cardiomyocytes and hiPSC-CMs treated with the oxidant chloramine T (ChT) developed a moderate reduction in peak current amplitudes accompanied by large late Na+ currents. While ChT induced a strong reduction in peak current amplitudes but only small persistent currents on Nav1.5, both Nav1.2 and Nav1.3 produced increased peak current amplitudes and large persistent currents following oxidation. TTX (300 nM) blocked ChT-induced late Na+ currents significantly stronger as compared to peak Na+ currents in both mouse cardiomyocytes and hiPSC-CMs. Similar differences between Nav1.2, Nav1.3, and Nav1.5 regarding ROS sensitivity were also evident when oxidation was induced with UVA-light (380 nm) or the cysteine-selective oxidant nitroxyl (HNO). To conclude, our data on TTX-sensitive Na+ channels expressed in cardiomyocytes may be relevant for the generation of late Na+ currents following oxidative stress.
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Affiliation(s)
- Anja Schneider
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, 30625 Hannover, Germany (A.H.); (I.C.A.P.S.)
| | - Axel Hage
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, 30625 Hannover, Germany (A.H.); (I.C.A.P.S.)
| | | | - Nils Kriedemann
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery (HTTG), REBIRTH—Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Robert Zweigerdt
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery (HTTG), REBIRTH—Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Andreas Leffler
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, 30625 Hannover, Germany (A.H.); (I.C.A.P.S.)
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2
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Mabry SA, Pavon N. Exploring the prospects, advancements, and challenges of in vitro modeling of the heart-brain axis. Front Cell Neurosci 2024; 18:1386355. [PMID: 38766369 PMCID: PMC11099243 DOI: 10.3389/fncel.2024.1386355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/12/2024] [Indexed: 05/22/2024] Open
Abstract
Research on bidirectional communication between the heart and brain has often relied on studies involving nonhuman animals. Dependance on animal models offer limited applicability to humans and a lack of high-throughput screening. Recently, the field of 3D cell biology, specifically organoid technology, has rapidly emerged as a valuable tool for studying interactions across organ systems, i.e., gut-brain axis. The initial success of organoid models indicates the usefulness of 3D cultures for elucidating the intricate interactivity of the autonomic nervous system and overall health. This perspective aims to explore the potential of advancing in vitro modeling of the heart-brain axis by discussing the benefits, applications, and adaptability of organoid technologies. We closely examine the current state of brain organoids in conjunction with the advancements of cardiac organoids. Moreover, we explore the use of combined organoid systems to investigate pathophysiology and provide a platform for treatment discovery. Finally, we address the challenges that accompany the use of 3D models for studying the heart-brain axis with an emphasis on generating tailored engineering strategies for further refinement of dynamic organ system modeling in vitro.
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Affiliation(s)
- Senegal Alfred Mabry
- Affect and Cognition Laboratory, Department of Psychology and Human Development, College of Human Ecology, Cornell University, Ithaca, NY, United States
| | - Narciso Pavon
- ChangHui Pak Laboratory, Department of Biochemistry and Molecular Biology, College of Natural Sciences, University of Massachusetts-Amherst, Amherst, MA, United States
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3
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King DR, Demirtas M, Tarasov M, Struckman HL, Meng X, Nassal D, Moise N, Miller A, Min D, Soltisz AM, Anne MNK, Alves Dias PA, Wagnon JL, Weinberg SH, Hund TJ, Veeraraghavan R, Radwański PB. Cardiac-Specific Deletion of Scn8a Mitigates Dravet Syndrome-Associated Sudden Death in Adults. JACC Clin Electrophysiol 2024; 10:829-842. [PMID: 38430092 PMCID: PMC11285447 DOI: 10.1016/j.jacep.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 12/27/2023] [Accepted: 01/03/2024] [Indexed: 03/03/2024]
Abstract
BACKGROUND Sudden unexpected death in epilepsy (SUDEP) is a fatal complication experienced by otherwise healthy epilepsy patients. Dravet syndrome (DS) is an inherited epileptic disorder resulting from loss of function of the voltage-gated sodium channel, NaV 1.1, and is associated with particularly high SUDEP risk. Evidence is mounting that NaVs abundant in the brain also occur in the heart, suggesting that the very molecular mechanisms underlying epilepsy could also precipitate cardiac arrhythmias and sudden death. Despite marked reduction of NaV 1.1 functional expression in DS, pathogenic late sodium current (INa,L) is paradoxically increased in DS hearts. However, the mechanisms by which DS directly impacts the heart to promote sudden death remain unclear. OBJECTIVES In this study, the authors sought to provide evidence implicating remodeling of Na+ - and Ca2+ -handling machinery, including NaV 1.6 and Na+/Ca2+exchanger (NCX) within transverse (T)-tubules in DS-associated arrhythmias. METHODS The authors undertook scanning ion conductance microscopy (SICM)-guided patch clamp, super-resolution microscopy, confocal Ca2+ imaging, and in vivo electrocardiography studies in Scn1a haploinsufficient murine model of DS. RESULTS DS promotes INa,L in T-tubular nanodomains, but not in other subcellular regions. Consistent with increased NaV activity in these regions, super-resolution microscopy revealed increased NaV 1.6 density near Ca2+release channels, the ryanodine receptors (RyR2) and NCX in DS relative to WT hearts. The resulting INa,L in these regions promoted aberrant Ca2+ release, leading to ventricular arrhythmias in vivo. Cardiac-specific deletion of NaV 1.6 protects adult DS mice from increased T-tubular late NaV activity and the resulting arrhythmias, as well as sudden death. CONCLUSIONS These data demonstrate that NaV 1.6 undergoes remodeling within T-tubules of adult DS hearts serving as a substrate for Ca2+ -mediated cardiac arrhythmias and may be a druggable target for the prevention of SUDEP in adult DS subjects.
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Affiliation(s)
- D Ryan King
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Mustafa Demirtas
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Mikhail Tarasov
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Heather L Struckman
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Xiaolei Meng
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Drew Nassal
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Nicolae Moise
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Alec Miller
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Dennison Min
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Andrew M Soltisz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Midhun N K Anne
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Patrícia A Alves Dias
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Charles University, Akademika Heyrovského Hradec Králové, Czech Republic
| | - Jacy L Wagnon
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Seth H Weinberg
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA; Department of Internal Medicine, Division of Cardiovascular Medicine, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Rengasayee Veeraraghavan
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Przemysław B Radwański
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA; Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA.
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4
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Reisqs JB, Qu YS, Boutjdir M. Ion channel trafficking implications in heart failure. Front Cardiovasc Med 2024; 11:1351496. [PMID: 38420267 PMCID: PMC10899472 DOI: 10.3389/fcvm.2024.1351496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 01/25/2024] [Indexed: 03/02/2024] Open
Abstract
Heart failure (HF) is recognized as an epidemic in the contemporary world, impacting around 1%-2% of the adult population and affecting around 6 million Americans. HF remains a major cause of mortality, morbidity, and poor quality of life. Several therapies are used to treat HF and improve the survival of patients; however, despite these substantial improvements in treating HF, the incidence of HF is increasing rapidly, posing a significant burden to human health. The total cost of care for HF is USD 69.8 billion in 2023, warranting a better understanding of the mechanisms involved in HF. Among the most serious manifestations associated with HF is arrhythmia due to the electrophysiological changes within the cardiomyocyte. Among these electrophysiological changes, disruptions in sodium and potassium currents' function and trafficking, as well as calcium handling, all of which impact arrhythmia in HF. The mechanisms responsible for the trafficking, anchoring, organization, and recycling of ion channels at the plasma membrane seem to be significant contributors to ion channels dysfunction in HF. Variants, microtubule alterations, or disturbances of anchoring proteins lead to ion channel trafficking defects and the alteration of the cardiomyocyte's electrophysiology. Understanding the mechanisms of ion channels trafficking could provide new therapeutic approaches for the treatment of HF. This review provides an overview of the recent advances in ion channel trafficking in HF.
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Affiliation(s)
- Jean-Baptiste Reisqs
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
| | - Yongxia Sarah Qu
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
- Department of Cardiology, New York Presbyterian Brooklyn Methodist Hospital, New York, NY, United States
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, New York, NY, United States
- Department of Medicine, New York University Grossman School of Medicine, New York, NY, United States
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5
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Mokrov GV. Multitargeting in cardioprotection: An example of biaromatic compounds. Arch Pharm (Weinheim) 2023; 356:e2300196. [PMID: 37345968 DOI: 10.1002/ardp.202300196] [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: 04/05/2023] [Revised: 05/23/2023] [Accepted: 05/26/2023] [Indexed: 06/23/2023]
Abstract
A multitarget drug design approach is actively developing in modern medicinal chemistry and pharmacology, especially with regard to multifactorial diseases such as cardiovascular diseases, cancer, and neurodegenerative diseases. A detailed study of many well-known drugs developed within the single-target approach also often reveals additional mechanisms of their real pharmacological action. One of the multitarget drug design approaches can be the identification of the basic pharmacophore models corresponding to a wide range of the required target ligands. Among such models in the group of cardioprotectors is the linked biaromatic system. This review develops the concept of a "basic pharmacophore" using the biaromatic pharmacophore of cardioprotectors as an example. It presents an analysis of possible biological targets for compounds corresponding to the biaromatic pharmacophore and an analysis of the spectrum of biological targets for the five most known and most studied cardioprotective drugs corresponding to this model, and their involvement in the biological effects of these drugs.
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6
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Yu C, Deng XJ, Xu D. Gene mutations in comorbidity of epilepsy and arrhythmia. J Neurol 2023; 270:1229-1248. [PMID: 36376730 DOI: 10.1007/s00415-022-11430-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022]
Abstract
Epilepsy is one of the most common neurological disorders, and sudden unexpected death in epilepsy (SUDEP) is the most severe outcome of refractory epilepsy. Arrhythmia is one of the heterogeneous factors in the pathophysiological mechanism of SUDEP with a high incidence in patients with refractory epilepsy, increasing the risk of premature death. The gene co-expressed in the brain and heart is supposed to be the genetic basis between epilepsy and arrhythmia, among which the gene encoding ion channel contributes to the prevalence of "cardiocerebral channelopathy" theory. Nevertheless, this theory could only explain the molecular mechanism of comorbid arrhythmia in part of patients with epilepsy (PWE). Therefore, we summarized the mutant genes that can induce comorbidity of epilepsy and arrhythmia and the possible corresponding treatments. These variants involved the genes encoding sodium, potassium, calcium and HCN channels, as well as some non-ion channel coding genes such as CHD4, PKP2, FHF1, GNB5, and mitochondrial genes. The relationship between genotype and clinical phenotype was not simple linear. Indeed, genes co-expressed in the brain and heart could independently induce epilepsy and/or arrhythmia. Mutant genes in brain could affect cardiac rhythm through central or peripheral regulation, while in the heart it could also affect cerebral electrical activity by changing the hemodynamics or internal environment. Analysis of mutations in comorbidity of epilepsy and arrhythmia could refine and expand the theory of "cardiocerebral channelopathy" and provide new insights for risk stratification of premature death and corresponding precision therapy in PWE.
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Affiliation(s)
- Cheng Yu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Xue-Jun Deng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Da Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China.
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7
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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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8
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Concise Review: Stem Cell Models of SCN1A-Related Encephalopathies—Current Perspective and Future Therapies. Cells 2022; 11:cells11193119. [PMID: 36231081 PMCID: PMC9561991 DOI: 10.3390/cells11193119] [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: 08/26/2022] [Revised: 09/23/2022] [Accepted: 09/28/2022] [Indexed: 11/17/2022] Open
Abstract
Mutations in the SCN1A gene can cause a variety of phenotypes, ranging from mild forms, such as febrile seizures and generalized epilepsy with febrile seizures plus, to severe, such as Dravet and non-Dravet developmental epileptic encephalopathies. Until now, more than two thousand pathogenic variants of the SCN1A gene have been identified and different pathogenic mechanisms (loss vs. gain of function) described, but the precise molecular mechanisms responsible for the deficits exhibited by patients are not fully elucidated. Additionally, the phenotypic variability proves the involvement of other genetic factors in its final expression. This is the reason why animal models and cell line models used to explore the molecular pathology of SCN1A-related disorders are only of limited use. The results of studies based on such models cannot be directly translated to affected individuals because they do not address each patient’s unique genetic background. The generation of functional neurons and glia for patient-derived iPSCs, together with the generation of isogenic controls using CRISPR/Cas technology, and finally, the 3D brain organoid models, seem to be a good way to solve this problem. Here, we review SCN1A-related encephalopathies, as well as the stem cell models used to explore their molecular basis.
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9
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Abramochkin DV, Filatova TS, Pustovit KB, Voronina YA, Kuzmin VS, Vornanen M. Ionic currents underlying different patterns of electrical activity in working cardiac myocytes of mammals and non-mammalian vertebrates. Comp Biochem Physiol A Mol Integr Physiol 2022; 268:111204. [PMID: 35346823 DOI: 10.1016/j.cbpa.2022.111204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 12/19/2022]
Abstract
The orderly contraction of the vertebrate heart is determined by generation and propagation of cardiac action potentials (APs). APs are generated by the integrated activity of time- and voltage-dependent ionic channels which carry inward Na+ and Ca2+ currents, and outward K+ currents. This review compares atrial and ventricular APs and underlying ion currents between different taxa of vertebrates. We have collected literature data and attempted to find common electrophysiological features for two or more vertebrate groups, show differences between taxa and cardiac chambers, and indicate gaps in the existing data. Although electrical excitability of the heart in all vertebrates is based on the same superfamily of channels, there is a vast variability of AP waveforms between atrial and ventricular myocytes, between different species of the same vertebrate class and between endothermic and ectothermic animals. The wide variability of AP shapes is related to species-specific differences in animal size, heart rate, stage of ontogenetic development, excitation-contraction coupling, temperature and oxygen availability. Some of the differences between taxa are related to evolutionary development of genomes, which appear e.g. in the expression of different Na+ and K+ channel orthologues in cardiomyocytes of vertebrates. There is a wonderful variability of AP shapes and underlying ion currents with which electrical excitability of vertebrate heart can be generated depending on the intrinsic and extrinsic conditions of animal body. This multitude of ionic mechanisms provides excellent material for studying how the function of the vertebrate heart can adapt or acclimate to prevailing physiological and environmental conditions.
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Affiliation(s)
- Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia.
| | - Tatiana S Filatova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
| | - Ksenia B Pustovit
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
| | - Yana A Voronina
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia; Laboratory of Cardiac Electrophysiology, National Medical Research Center for Cardiology, 3(rd) Cherepkovskaya str., 15A, Moscow, Russia
| | - Vladislav S Kuzmin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia; Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova str., 1, Moscow, Russia
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
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10
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Ranolazine: An Old Drug with Emerging Potential; Lessons from Pre-Clinical and Clinical Investigations for Possible Repositioning. Pharmaceuticals (Basel) 2021; 15:ph15010031. [PMID: 35056088 PMCID: PMC8777683 DOI: 10.3390/ph15010031] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 02/07/2023] Open
Abstract
Ischemic heart disease is a significant public health problem with high mortality and morbidity. Extensive scientific investigations from basic sciences to clinics revealed multilevel alterations from metabolic imbalance, altered electrophysiology, and defective Ca2+/Na+ homeostasis leading to lethal arrhythmias. Despite the recent identification of numerous molecular targets with potential therapeutic interest, a pragmatic observation on the current pharmacological R&D output confirms the lack of new therapeutic offers to patients. By contrast, from recent trials, molecules initially developed for other fields of application have shown cardiovascular benefits, as illustrated with some anti-diabetic agents, regardless of the presence or absence of diabetes, emphasizing the clear advantage of “old” drug repositioning. Ranolazine is approved as an antianginal agent and has a favorable overall safety profile. This drug, developed initially as a metabolic modulator, was also identified as an inhibitor of the cardiac late Na+ current, although it also blocks other ionic currents, including the hERG/Ikr K+ current. The latter actions have been involved in this drug’s antiarrhythmic effects, both on supraventricular and ventricular arrhythmias (VA). However, despite initial enthusiasm and promising development in the cardiovascular field, ranolazine is only authorized as a second-line treatment in patients with chronic angina pectoris, notwithstanding its antiarrhythmic properties. A plausible reason for this is the apparent difficulty in linking the clinical benefits to the multiple molecular actions of this drug. Here, we review ranolazine’s experimental and clinical knowledge on cardiac metabolism and arrhythmias. We also highlight advances in understanding novel effects on neurons, the vascular system, skeletal muscles, blood sugar control, and cancer, which may open the way to reposition this “old” drug alone or in combination with other medications.
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11
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Husti Z, Varró A, Baczkó I. Arrhythmogenic Remodeling in the Failing Heart. Cells 2021; 10:cells10113203. [PMID: 34831426 PMCID: PMC8623396 DOI: 10.3390/cells10113203] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 12/12/2022] Open
Abstract
Chronic heart failure is a clinical syndrome with multiple etiologies, associated with significant morbidity and mortality. Cardiac arrhythmias, including ventricular tachyarrhythmias and atrial fibrillation, are common in heart failure. A number of cardiac diseases including heart failure alter the expression and regulation of ion channels and transporters leading to arrhythmogenic electrical remodeling. Myocardial hypertrophy, fibrosis and scar formation are key elements of arrhythmogenic structural remodeling in heart failure. In this article, the mechanisms responsible for increased arrhythmia susceptibility as well as the underlying changes in ion channel, transporter expression and function as well as alterations in calcium handling in heart failure are discussed. Understanding the mechanisms of arrhythmogenic remodeling is key to improving arrhythmia management and the prevention of sudden cardiac death in patients with heart failure.
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Affiliation(s)
- Zoltán Husti
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research Network, 6720 Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
- Correspondence:
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12
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Shi L, Li Y, Liu Q, Zhang L, Wang L, Liu X, Gao H, Hou X, Zhao F, Yan H, Wang L. Identification of SNPs and Candidate Genes for Milk Production Ability in Yorkshire Pigs. Front Genet 2021; 12:724533. [PMID: 34675963 PMCID: PMC8523896 DOI: 10.3389/fgene.2021.724533] [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: 06/13/2021] [Accepted: 09/22/2021] [Indexed: 12/01/2022] Open
Abstract
Sow milk production ability is an important limiting factor impacting suboptimal growth and the survival of piglets. Through pig genetic improvement, litter sizes have been increased. Larger litters need more suckling mammary glands, which results in increased milk from the lactating sow. Hence, there is much significance to exploring sow lactation performance. For milk production ability, it is not practical to directly measure the milk yield, we used litter weight gain (LWG) throughout sow lactation as an indicator. In this study, we estimated the heritability of LWG, namely, 0.18 ± 0.07. We then performed a GWAS, and detected seven significant SNPs, namely, Sus scrofa Chromosome (SSC) 2: ASGA0010040 (p = 7.73E-11); SSC2:MARC0029355 (p = 1.30E-08), SSC6: WU_10.2_6_65751151 (p = 1.32E-10), SSC7: MARC0058875 (p = 4.99E-09), SSC10: WU_10.2_10_49571394 (p = 6.79E-08), SSC11: M1GA0014659 (p = 1.19E-07), and SSC15: MARC0042106 (p = 1.16E-07). We performed the distribution of phenotypes corresponding to the genotypes of seven significant SNPs and showed that ASGA0010040, MARC0029355, MARC0058875, WU_10.2_10_49571394, M1GA0014659, and MARC0042106 had extreme phenotypic values that corresponded to the homozygous genotypes, while the intermediate values corresponded to the heterozygous genotypes. We screened for flanking regions ± 200 kb nearby the seven significant SNPs, and identified 38 genes in total. Among them, 28 of the candidates were involved in lactose metabolism, colostrum immunity, milk protein, and milk fat by functional enrichment analysis. Through the combined analysis between 28 candidate genes and transcriptome data of the sow mammary gland, we found nine commons (ANO3, MUC15, DISP3, FBXO6, CLCN6, HLA-DRA, SLA-DRB1, SLA-DQB1, and SLA-DQA1). Furthermore, by comparing the chromosome positions of the candidate genes with the quantitative trait locus (QTLs) as previously reported, a total of 17 genes were found to be within 0.86–94.02 Mb of the reported QTLs for sow milk production ability, in which, NAV2 was found to be located with 0.86 Mb of the QTL region ssc2: 40936355. In conclusion, we identified seven significant SNPs located on SSC2, 6, 7, 10, 11, and 15, and propose 28 candidate genes for the ability to produce milk in Yorkshire pigs, 10 of which were key candidates.
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Affiliation(s)
- Lijun Shi
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yang Li
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qian Liu
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Longchao Zhang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ligang Wang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xin Liu
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hongmei Gao
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xinhua Hou
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fuping Zhao
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hua Yan
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lixian Wang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
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13
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Sullo F, Pasquetti E, Patanè F, Lo Bianco M, Marino SD, Polizzi A, Falsaperla R, Ruggieri M, Zanghì A, Praticò AD. SCN1A and Its Related Epileptic Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractEpilepsy is one of the most common neurological disorders, with a lifetime incidence of 1 in 26. Approximately two-thirds of epilepsy has a substantial genetic component in its etiology. As a result, simultaneous screening for mutations in multiple genes and performing whole exome sequencing (WES) are becoming very frequent in the clinical evaluation of children with epilepsy. In this setting, mutations in voltage-gated sodium channel (SCN) α-subunit genes are the most commonly identified cause of epilepsy, with sodium channel genes (i.e., SCN1A, SCN2A, SCN8A) being the most frequently identified causative genes. SCN1A mutations result in a wide spectrum of epilepsy phenotypes ranging from simple febrile seizures to Dravet syndrome, a severe epileptic encephalopathy. In case of mutation of SCN1A, it is also possible to observe behavioral alterations, such as impulsivity, inattentiveness, and distractibility, which can be framed in an attention deficit hyperactivity disorder (ADHD) like phenotype. Despite more than 1,200 SCN1A mutations being reported, it is not possible to assess a clear phenotype–genotype correlations. Treatment remains a challenge and seizure control is often partial and transitory.
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Affiliation(s)
- Federica Sullo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Elisa Pasquetti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Francesca Patanè
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Simona D. Marino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Martino Ruggieri
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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14
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Lorenzini M, Burel S, Lesage A, Wagner E, Charrière C, Chevillard PM, Evrard B, Maloney D, Ruff KM, Pappu RV, Wagner S, Nerbonne JM, Silva JR, Townsend RR, Maier LS, Marionneau C. Proteomic and functional mapping of cardiac NaV1.5 channel phosphorylation sites. J Gen Physiol 2021; 153:211660. [PMID: 33410863 PMCID: PMC7797897 DOI: 10.1085/jgp.202012646] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/23/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022] Open
Abstract
Phosphorylation of the voltage-gated Na+ (NaV) channel NaV1.5 regulates cardiac excitability, yet the phosphorylation sites regulating its function and the underlying mechanisms remain largely unknown. Using a systematic, quantitative phosphoproteomic approach, we analyzed NaV1.5 channel complexes purified from nonfailing and failing mouse left ventricles, and we identified 42 phosphorylation sites on NaV1.5. Most sites are clustered, and three of these clusters are highly phosphorylated. Analyses of phosphosilent and phosphomimetic NaV1.5 mutants revealed the roles of three phosphosites in regulating NaV1.5 channel expression and gating. The phosphorylated serines S664 and S667 regulate the voltage dependence of channel activation in a cumulative manner, whereas the nearby S671, the phosphorylation of which is increased in failing hearts, regulates cell surface NaV1.5 expression and peak Na+ current. No additional roles could be assigned to the other clusters of phosphosites. Taken together, our results demonstrate that ventricular NaV1.5 is highly phosphorylated and that the phosphorylation-dependent regulation of NaV1.5 channels is highly complex, site specific, and dynamic.
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Affiliation(s)
- Maxime Lorenzini
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Sophie Burel
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Adrien Lesage
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Emily Wagner
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Camille Charrière
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Pierre-Marie Chevillard
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Bérangère Evrard
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Dan Maloney
- Bioinformatics Solutions Inc., Waterloo, Ontario, Canada
| | - Kiersten M Ruff
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Rohit V Pappu
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Stefan Wagner
- Department of Internal Medicine II, University Heart Center, University Hospital Regensburg, Regensburg, Germany
| | - Jeanne M Nerbonne
- Department of Developmental Biology, Washington University Medical School, St. Louis, MO.,Department of Medicine, Washington University Medical School, St. Louis, MO
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - R Reid Townsend
- Department of Medicine, Washington University Medical School, St. Louis, MO.,Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, MO
| | - Lars S Maier
- Department of Internal Medicine II, University Heart Center, University Hospital Regensburg, Regensburg, Germany
| | - Céline Marionneau
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
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15
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Torres NS. Activation of reverse Na +-Ca 2+ exchanger by skeletal Na + channel isoform increases excitation-contraction coupling efficiency in rabbit cardiomyocytes. Am J Physiol Heart Circ Physiol 2020; 320:H593-H603. [PMID: 33275521 DOI: 10.1152/ajpheart.00545.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Our prior work has shown that Na+ current (INa) affects sarcoplasmic reticular (SR) Ca2+ release by activating early reverse of the Na+-Ca2+ exchanger (NCX). The resulting Ca2+ entry primes the dyadic cleft, which appears to increase Ca2+ channel coupling fidelity. It has been shown that the skeletal isoform of the voltage-gated Na+ channel (Nav1.4) is the main tetrodotoxin (TTX)-sensitive Nav isoform expressed in adult rabbit ventricular cardiomyocytes. Here, I tested the hypothesis that it is also the principal isoform involved in the priming mechanism. Action potentials (APs) were evoked in isolated rabbit ventricular cells loaded with fluo-4, and simultaneously recorded Ca2+ transients before and after the application of either relatively low doses of TTX (100 nM), the specific Nav1.4 inhibitor μ-Conotoxin GIIIB or the specific Nav1.1 inhibitor ICA 121430. Although APs changes after the application of each drug reflected the relative abundance of each isoform, the effects of TTX and GIIIB on SR Ca2+ release (measured as the transient maximum upstroke velocity) were no different. Furthermore, this reduction in SR Ca2+ release was comparable with the value that we obtained previously when total INa was inactivated with a ramp applied under voltage clamp. Finally, SR Ca2+ release was unaltered by the same ramp in the presence of TTX or GIIB. In contrast, application of ICA had no effect of SR Ca2+ release. These results suggest that Nav1.4 is the main Nav isoform involved in regulating the efficiency of excitation-contraction coupling in rabbit cardiomyocytes by priming the junction via activation of reverse-mode NCX.NEW & NOTEWORTHY A number of studies suggest that the Na+-Ca2+ exchanger (NCX) activated by Na+ currents is involved in the process of excitation-contraction (EC) coupling in cardiac ventricular myocytes. Although insufficient to trigger sarcoplasmic Ca2+ release alone, the Ca2+ entering through reverse NCX during an action potential can prime the dyadic cleft and increase the Ca2+ current coupling fidelity. Using specific Na+ inhibitors in this study, we show that in rabbit ventricular cells the skeletal Na+ channel isoform (Nav1.4) is the main isoform responsible for this priming. Our study provides insights into a mechanism that may have an increased relevance where EC coupling is remodeled.
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Affiliation(s)
- Natalia S Torres
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
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16
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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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17
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Munger MA, Olğar Y, Koleske ML, Struckman HL, Mandrioli J, Lou Q, Bonila I, Kim K, Ramos Mondragon R, Priori SG, Volpe P, Valdivia HH, Biskupiak J, Carnes CA, Veeraraghavan R, Györke S, Radwański PB. Tetrodotoxin-Sensitive Neuronal-Type Na + Channels: A Novel and Druggable Target for Prevention of Atrial Fibrillation. J Am Heart Assoc 2020; 9:e015119. [PMID: 32468902 PMCID: PMC7429002 DOI: 10.1161/jaha.119.015119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Atrial fibrillation (AF) is a comorbidity associated with heart failure and catecholaminergic polymorphic ventricular tachycardia. Despite the Ca2+‐dependent nature of both of these pathologies, AF often responds to Na+ channel blockers. We investigated how targeting interdependent Na+/Ca2+ dysregulation might prevent focal activity and control AF. Methods and Results We studied AF in 2 models of Ca2+‐dependent disorders, a murine model of catecholaminergic polymorphic ventricular tachycardia and a canine model of chronic tachypacing‐induced heart failure. Imaging studies revealed close association of neuronal‐type Na+ channels (nNav) with ryanodine receptors and Na+/Ca2+ exchanger. Catecholamine stimulation induced cellular and in vivo atrial arrhythmias in wild‐type mice only during pharmacological augmentation of nNav activity. In contrast, catecholamine stimulation alone was sufficient to elicit atrial arrhythmias in catecholaminergic polymorphic ventricular tachycardia mice and failing canine atria. Importantly, these were abolished by acute nNav inhibition (tetrodotoxin or riluzole) implicating Na+/Ca2+ dysregulation in AF. These findings were then tested in 2 nonrandomized retrospective cohorts: an amyotrophic lateral sclerosis clinic and an academic medical center. Riluzole‐treated patients adjusted for baseline characteristics evidenced significantly lower incidence of arrhythmias including new‐onset AF, supporting the preclinical results. Conclusions These data suggest that nNaVs mediate Na+‐Ca2+ crosstalk within nanodomains containing Ca2+ release machinery and, thereby, contribute to AF triggers. Disruption of this mechanism by nNav inhibition can effectively prevent AF arising from diverse causes.
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Affiliation(s)
- Mark A Munger
- Departments of Pharmacotherapy and Internal Medicine University of Utah Health Sciences Center Salt Lake City UT
| | - Yusuf Olğar
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Megan L Koleske
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Heather L Struckman
- Department of Biomedical Engineering College of Engineering The Ohio State University Columbus OH
| | - Jessica Mandrioli
- Department of Neuroscience St. Agostino Estense Hospital Azienda Ospedaliero Universitaria di Modena Italy
| | - Qing Lou
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Ingrid Bonila
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Kibum Kim
- Department of Pharmacotherapy University of Utah Health Sciences Center Salt Lake City UT
| | - Roberto Ramos Mondragon
- Department of Internal Medicine and of Molecular & Integrative Physiology University of Michigan Ann Arbor MI
| | - Silvia G Priori
- Molecular Cardiology Istituti Clinici Scientifici Maugeri IRCCS University of Pavia Italy.,Department of Molecular Medicine University of Pavia Italy
| | - Pompeo Volpe
- Department of Biomedical Sciences University of Padova Italy
| | - Héctor H Valdivia
- Department of Internal Medicine and of Molecular & Integrative Physiology University of Michigan Ann Arbor MI
| | - Joseph Biskupiak
- Department of Pharmacotherapy University of Utah Health Sciences Center Salt Lake City UT
| | - Cynthia A Carnes
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering College of Engineering The Ohio State University Columbus OH.,Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
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18
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Contribution of the neuronal sodium channel Na V1.8 to sodium- and calcium-dependent cellular proarrhythmia. J Mol Cell Cardiol 2020; 144:35-46. [PMID: 32418916 DOI: 10.1016/j.yjmcc.2020.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 04/17/2020] [Accepted: 05/05/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVE In myocardial pathology such as heart failure a late sodium current (INaL) augmentation is known to be involved in conditions of arrhythmogenesis. However, the underlying mechanisms of the INaL generation are not entirely understood. By now evidence is growing that non-cardiac sodium channel isoforms could also be involved in the INaL generation. The present study investigates the contribution of the neuronal sodium channel isoform NaV1.8 to arrhythmogenesis in a clearly-defined setting of enhanced INaL by using anemone toxin II (ATX-II) in the absence of structural heart disease. METHODS Electrophysiological experiments were performed in order to measure INaL, action potential duration (APD), SR-Ca2+-leak and cellular proarrhythmic triggers in ATX-II exposed wild-type (WT) and SCN10A-/- mice cardiomyocytes. In addition, WT cardiomyocytes were stimulated with ATX-II in the presence or absence of NaV1.8 inhibitors. INCX was measured by using the whole cell patch clamp method. RESULTS In WT cardiomyocytes exposure to ATX-II augmented INaL, prolonged APD, increased SR-Ca2+-leak and induced proarrhythmic triggers such as early afterdepolarizations (EADs) and Ca2+-waves. All of them could be significantly reduced by applying NaV1.8 blockers PF-01247324 and A-803467. Both blockers had no relevant effects on cellular electrophysiology of SCN10A-/- cardiomyocytes. Moreover, in SCN10A-/--cardiomyocytes, the ATX-II-dependent increase in INaL, SR-Ca2+-leak and APD prolongation was less than in WT and comparable to the results which were obtained with WT cardiomyocytes being exposed to ATX-II and NaV1.8 inhibitors in parallel. Moreover, we found a decrease in reverse mode NCX current and reduced CaMKII-dependent RyR2-phosphorylation after application of PF-01247324 as an underlying explanation for the Na+-mediated Ca2+-dependent proarrhythmic triggers. CONCLUSION The current findings demonstrate that NaV1.8 is a significant contributor for INaL-induced arrhythmic triggers. Therefore, NaV1.8 inhibition under conditions of an enhanced INaL constitutes a promising antiarrhythmic strategy which merits further investigation.
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19
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Dybkova N, Ahmad S, Pabel S, Tirilomis P, Hartmann N, Fischer TH, Bengel P, Tirilomis T, Ljubojevic S, Renner A, Gummert J, Ellenberger D, Wagner S, Frey N, Maier LS, Streckfuss-Bömeke K, Hasenfuss G, Sossalla S. Differential regulation of sodium channels as a novel proarrhythmic mechanism in the human failing heart. Cardiovasc Res 2019; 114:1728-1737. [PMID: 29931291 DOI: 10.1093/cvr/cvy152] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 06/15/2018] [Indexed: 12/18/2022] Open
Abstract
Aims In heart failure (HF), enhanced persistent Na+ current (INaL) exerts detrimental effects on cellular electrophysiology and can induce arrhythmias. However, the underlying regulatory mechanisms remain unclear. Our aim was to potentially investigate the regulation and electrophysiological contribution of neuronal sodium channel NaV1.8 in failing human heart and eventually to reveal a novel anti-arrhythmic therapy. Methods and results By western blot, we found that NaV1.8 protein expression is significantly up-regulated, while of the predominant cardiac isoform NaV1.5 is inversely reduced in human HF. Furthermore, to investigate the relation of NaV1.8 regulation with the cellular proarrhythmic events, we performed comprehensive electrophysiology recordings and explore the effect of NaV1.8 on INaL, action potential duration (APD), Ca2+ spark frequency, and arrhythmia induction in human failing cardiomyocytes. NaV1.8 inhibition with the specific blockers A-803467 and PF-01247324 decreased INaL, abbreviated APD and reduced cellular-spontaneous Ca2+-release and proarrhythmic events in human failing cardiomyocytes. Consistently, in mouse cardiomyocytes stressed with isoproterenol, pharmacologic inhibition and genetically knockout of NaV1.8 (SCN10A-/-), were associated with reduced INaL and abbreviated APD. Conclusion We provide first evidence of differential regulation of NaV1.8 and NaV1.5 in the failing human myocardium and their contribution to arrhythmogenesis due to generation of INaL. We propose inhibition of NaV1.8 thus constitutes a promising novel approach for selective anti-arrhythmic therapy in HF.
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Affiliation(s)
- Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Shakil Ahmad
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Steffen Pabel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Petros Tirilomis
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Nico Hartmann
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Thomas H Fischer
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Philipp Bengel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Theodoros Tirilomis
- Department of Thoracic, Cardiac and Vascular Surgery, Georg-August University Goettingen, Germany
| | | | - André Renner
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - Jan Gummert
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - David Ellenberger
- Department of Medical Statistics, University Medical Center Goettingen, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Norbert Frey
- Department of Internal Medicine III, Molecular Cardiology and Angiology, University Medical Center, Campus Kiel, Schleswig-Holstein, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Samuel Sossalla
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
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20
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Wu M, Tran PN, Sheng J, Randolph AL, Wu WW. Drug potency on inhibiting late Na + current is sensitive to gating modifier and current region where drug effects were measured. J Pharmacol Toxicol Methods 2019; 100:106605. [PMID: 31255744 DOI: 10.1016/j.vascn.2019.106605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/18/2019] [Accepted: 06/24/2019] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Cardiac late Na+ current (INaL) contributes to ventricular action potential duration. Pathological increase in INaL is arrhythmogenic, and inhibition of INaL offers protection against ventricular repolarization disturbance. Recently, two INaL datasets generated by different laboratories that assessed current inhibition by a panel of clinical drugs as a part of the Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative were published. The results revealed a surprising degree of data variability despite of the use of a standardized voltage protocol. This study investigated whether remaining procedural differences related to experimental methods and data analysis associated with these datasets can produce differences in INaL pharmacology. METHODS Whole cell voltage clamp recordings were performed on cells expressing NaV1.5 α- and β1-subunits to study: 1) the impact of gating modifiers used to augment INaL (ATX-II vs. veratridine), internal solution composition (with vs. without ATP and GTP), and recording temperature (23 °C vs 37 °C) on stability of INaL measured across the duration of a patch clamp experiment; 2) mechanisms of each gating modifier on Na+ channels; and 3) effects of six drugs (lidocaine, mexiletine, chloroquine, ranolazine, ritonavir, and verapamil) on INaL induced by either gating modifier. RESULTS Stability of INaL is affected by the choice of gating modifier, presence of nucleotides in the internal solution, and recording temperature. ATX-II and veratridine produced different changes in Na+ channel gating, inducing mechanistically distinct INaL. Drug potencies on inhibiting INaL were dependent on the choice of gating modifier and current region where drug effects were measured. DISCUSSION INaL pharmacology can be impacted by all experimental factors examined in this study. The effect of gating modifier and current region used to quantify drug inhibition alone led to 30× difference in half inhibitory concentration (IC50) for ritonavir, demonstrating that substantial difference in drug inhibition can be produced. Drug potencies on inhibiting INaL derived from different patch clamp studies may thus not be generalizable. For INaL pharmacology to be useful for in silico modeling or interpreting drug-induced changes in cardiac action potentials or ECG, standardizing INaL experimental procedures including data analysis methods is necessary to minimize data variability.
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Affiliation(s)
- Min Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, The US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, United States of America
| | - Phu N Tran
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, The US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, United States of America
| | - Jiansong Sheng
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, The US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, United States of America
| | - Aaron L Randolph
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, The US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, United States of America
| | - Wendy W Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, The US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, United States of America.
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Peyronnet R, Ravens U. Atria-selective antiarrhythmic drugs in need of alliance partners. Pharmacol Res 2019; 145:104262. [PMID: 31059791 DOI: 10.1016/j.phrs.2019.104262] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/30/2019] [Accepted: 05/03/2019] [Indexed: 12/15/2022]
Abstract
Atria-selective antiarrhythmic drugs in need of alliance partners. Guideline-based treatment of atrial fibrillation (AF) comprises prevention of thromboembolism and stroke, as well as antiarrhythmic therapy by drugs, electrical rhythm conversion, ablation and surgical procedures. Conventional antiarrhythmic drugs are burdened with unwanted side effects including a propensity of triggering life-threatening ventricular fibrillation. In order to solve this therapeutic dilemma, 'atria-selective' antiarrhythmic drugs have been developed for the treatment of supraventricular arrhythmias. These drugs are designed to aim at atrial targets, taking advantage of differences in atrial and ventricular ion channel expression and function. However it is not clear, whether such drugs are sufficiently antiarrhythmic or whether they are in need of an alliance partner for clinical efficacy. Atria-selective Na+ channel blockers display fast dissociation kinetics and high binding affinity to inactivated channels. Compounds targeting atria-selective K+ channels include blockers of ultra rapid delayed rectifier (Kv1.5) or acetylcholine-activated inward rectifier K+ channels (Kir3.x), inward rectifying K+ channels (Kir2.x), Ca2+-activated K+ channels of small conductance (SK), weakly rectifying two-pore domain K+ channels (K2P), and transient receptor potential channels (TRP). Despite good antiarrhythmic data from in-vitro and animal model experiments, clinical efficacy of atria-selective antiarrhythmic drugs remains to be demonstrated. In the present review we will briefly summarize the novel compounds and their proposed antiarrhythmic action. In addition, we will discuss the evidence for putative improvement of antiarrhythmic efficacy and potency by addressing multiple pathophysiologically relevant targets as possible alliance partners.
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Affiliation(s)
- Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ursula Ravens
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany; Institute of Physiology, Medical Faculty TU Dresden, Dresden, Germany.
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22
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Hegyi B, Morotti S, Liu C, Ginsburg KS, Bossuyt J, Belardinelli L, Izu LT, Chen-Izu Y, Bányász T, Grandi E, Bers DM. Enhanced Depolarization Drive in Failing Rabbit Ventricular Myocytes: Calcium-Dependent and β-Adrenergic Effects on Late Sodium, L-Type Calcium, and Sodium-Calcium Exchange Currents. Circ Arrhythm Electrophysiol 2019; 12:e007061. [PMID: 30879336 PMCID: PMC6720130 DOI: 10.1161/circep.118.007061] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Heart failure (HF) is characterized by electrophysiological remodeling resulting in increased risk of cardiac arrhythmias. Previous reports suggest that elevated inward ionic currents in HF promote action potential (AP) prolongation, increased short-term variability of AP repolarization, and delayed afterdepolarizations. However, the underlying changes in late Na+ current (INaL), L-type Ca2+ current, and NCX (Na+/Ca2+ exchanger) current are often measured in nonphysiological conditions (square-pulse voltage clamp, slow pacing rates, exogenous Ca2+ buffers). METHODS We measured the major inward currents and their Ca2+- and β-adrenergic dependence under physiological AP clamp in rabbit ventricular myocytes in chronic pressure/volume overload-induced HF (versus age-matched control). RESULTS AP duration and short-term variability of AP repolarization were increased in HF, and importantly, inhibition of INaL decreased both parameters to the control level. INaL was slightly increased in HF versus control even when intracellular Ca2+ was strongly buffered. But under physiological AP clamp with normal Ca2+ cycling, INaL was markedly upregulated in HF versus control (dependent largely on CaMKII [Ca2+/calmodulin-dependent protein kinase II] activity). β-Adrenergic stimulation (often elevated in HF) further enhanced INaL. L-type Ca2+ current was decreased in HF when Ca2+ was buffered, but CaMKII-mediated Ca2+-dependent facilitation upregulated physiological L-type Ca2+ current to the control level. Furthermore, L-type Ca2+ current response to β-adrenergic stimulation was significantly attenuated in HF. Inward NCX current was upregulated at phase 3 of AP in HF when assessed by combining experimental data and computational modeling. CONCLUSIONS Our results suggest that CaMKII-dependent upregulation of INaL in HF significantly contributes to AP prolongation and increased short-term variability of AP repolarization, which may lead to increased arrhythmia propensity, and is further exacerbated by adrenergic stress.
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Affiliation(s)
- Bence Hegyi
- Department of Pharmacology, University of California Davis, Davis
| | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis
| | - Caroline Liu
- Department of Pharmacology, University of California Davis, Davis
| | | | - Julie Bossuyt
- Department of Pharmacology, University of California Davis, Davis
| | | | - Leighton T. Izu
- Department of Pharmacology, University of California Davis, Davis
| | - Ye Chen-Izu
- Department of Pharmacology, University of California Davis, Davis
- Department of Biomedical Engineering, University of California Davis, Davis
- Department of Internal Medicine/Cardiology, University of California Davis, Davis
| | - Tamás Bányász
- Department of Pharmacology, University of California Davis, Davis
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis
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23
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Wang W, Mellor RL, Nerbonne JM, Balke CW. Regional differences in the expression of tetrodotoxin-sensitive inward Ca 2+ and outward Cs +/K + currents in mouse and human ventricles. Channels (Austin) 2019; 13:72-87. [PMID: 30704344 PMCID: PMC6380286 DOI: 10.1080/19336950.2019.1568146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Tetrodotoxin (TTX) sensitive inward Ca2+ currents, ICa(TTX), have been identified in cardiac myocytes from several species, although it is unclear if ICa(TTX) is expressed in all cardiac cell types, and if ICa(TTX) reflects Ca2+ entry through the main, Nav1.5-encoded, cardiac Na+ (Nav) channels. To address these questions, recordings were obtained with 2 mm Ca2+ and 0 mm Na+ in the bath and 120 mm Cs+ in the pipettes from myocytes isolated from adult mouse interventricular septum (IVS), left ventricular (LV) endocardium, apex, and epicardium and from human LV endocardium and epicardium. On membrane depolarizations from a holding potential of −100 mV, ICa(TTX) was identified in mouse IVS and LV endocardial myocytes and in human LV endocardial myocytes, whereas only TTX-sensitive outward Cs+/K+ currents were observed in mouse LV apex and epicardial myocytes and human LV epicardial myocytes. The inward Ca2+, but not the outward Cs+/K+, currents were blocked by mm concentrations of MTSEA, a selective blocker of cardiac Nav1.5-encoded Na+ channels. In addition, in Nav1.5-expressing tsA-201 cells, ICa(TTX) was observed in 3 (of 20) cells, and TTX-sensitive outward Cs+/K+ currents were observed in the other (17) cells. The time- and voltage-dependent properties of the TTX-sensitive inward Ca2+ and outward Cs+/K+ currents recorded in Nav1.5-expressing tsA-201 were indistinguishable from native currents in mouse and human cardiac myocytes. Overall, the results presented here suggest marked regional, cell type-specific, differences in the relative ion selectivity, and likely the molecular architecture, of native SCN5A-/Scn5a- (Nav1.5-) encoded cardiac Na+ channels in mouse and human ventricles.
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Affiliation(s)
- Wei Wang
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA
| | - Rebecca L Mellor
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA
| | - Jeanne M Nerbonne
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA.,b John Cochran Veterans Administration Medical Center , St. Louis , MO , USA
| | - C William Balke
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA.,b John Cochran Veterans Administration Medical Center , St. Louis , MO , USA
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24
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Hegyi B, Bányász T, Izu LT, Belardinelli L, Bers DM, Chen-Izu Y. β-adrenergic regulation of late Na + current during cardiac action potential is mediated by both PKA and CaMKII. J Mol Cell Cardiol 2018; 123:168-179. [PMID: 30240676 DOI: 10.1016/j.yjmcc.2018.09.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/28/2018] [Accepted: 09/16/2018] [Indexed: 12/12/2022]
Abstract
Late Na+ current (INaL) significantly contributes to shaping cardiac action potentials (APs) and increased INaL is associated with cardiac arrhythmias. β-adrenergic receptor (βAR) stimulation and its downstream signaling via protein kinase A (PKA) and Ca2+/calmodulin-dependent protein kinase II (CaMKII) pathways are known to regulate INaL. However, it remains unclear how each of these pathways regulates INaL during the AP under physiological conditions. Here we performed AP-clamp experiments in rabbit ventricular myocytes to delineate the impact of each signaling pathway on INaL at different AP phases to understand the arrhythmogenic potential. During the physiological AP (2 Hz, 37 °C) we found that INaL had a basal level current independent of PKA, but partially dependent on CaMKII. βAR activation (10 nM isoproterenol, ISO) further enhanced INaL via both PKA and CaMKII pathways. However, PKA predominantly increased INaL early during the AP plateau, whereas CaMKII mainly increased INaL later in the plateau and during rapid repolarization. We also tested the role of key signaling pathways through exchange protein activated by cAMP (Epac), nitric oxide synthase (NOS) and reactive oxygen species (ROS). Direct Epac stimulation enhanced INaL similar to the βAR-induced CaMKII effect, while NOS inhibition prevented the βAR-induced CaMKII-dependent INaL enhancement. ROS generated by NADPH oxidase 2 (NOX2) also contributed to the ISO-induced INaL activation early in the AP. Taken together, our data reveal differential modulations of INaL by PKA and CaMKII signaling pathways at different AP phases. This nuanced and comprehensive view on the changes in INaL during AP deepens our understanding of the important role of INaL in reshaping the cardiac AP and arrhythmogenic potential under elevated sympathetic stimulation, which is relevant for designing therapeutic treatment of arrhythmias under pathological conditions.
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Affiliation(s)
- Bence Hegyi
- Department of Pharmacology, University of California, Davis, CA, USA.
| | - Tamás Bányász
- Department of Pharmacology, University of California, Davis, CA, USA; Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Leighton T Izu
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Ye Chen-Izu
- Department of Pharmacology, University of California, Davis, CA, USA; Department of Biomedical Engineering, University of California, Davis, CA, USA; Department of Internal Medicine/Cardiology, University of California, Davis, CA, USA.
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25
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Despa S. Myocyte [Na +] i Dysregulation in Heart Failure and Diabetic Cardiomyopathy. Front Physiol 2018; 9:1303. [PMID: 30258369 PMCID: PMC6144935 DOI: 10.3389/fphys.2018.01303] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 08/29/2018] [Indexed: 12/19/2022] Open
Abstract
By controlling the function of various sarcolemmal and mitochondrial ion transporters, intracellular Na+ concentration ([Na+]i) regulates Ca2+ cycling, electrical activity, the matching of energy supply and demand, and oxidative stress in cardiac myocytes. Thus, maintenance of myocyte Na+ homeostasis is vital for preserving the electrical and contractile activity of the heart. [Na+]i is set by the balance between the passive Na+ entry through numerous pathways and the pumping of Na+ out of the cell by the Na+/K+-ATPase. This equilibrium is perturbed in heart failure, resulting in higher [Na+]i. More recent studies have revealed that [Na+]i is also increased in myocytes from diabetic hearts. Elevated [Na+]i causes oxidative stress and augments the sarcoplasmic reticulum Ca2+ leak, thus amplifying the risk for arrhythmias and promoting heart dysfunction. This mini-review compares and contrasts the alterations in Na+ extrusion and/or Na+ uptake that underlie the [Na+]i increase in heart failure and diabetes, with a particular emphasis on the emerging role of Na+ - glucose cotransporters in the diabetic heart.
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Affiliation(s)
- Sanda Despa
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, United States
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26
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Frasier CR, Zhang H, Offord J, Dang LT, Auerbach DS, Shi H, Chen C, Goldman AM, Eckhardt LL, Bezzerides VJ, Parent JM, Isom LL. Channelopathy as a SUDEP Biomarker in Dravet Syndrome Patient-Derived Cardiac Myocytes. Stem Cell Reports 2018; 11:626-634. [PMID: 30146492 PMCID: PMC6135724 DOI: 10.1016/j.stemcr.2018.07.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 07/23/2018] [Accepted: 07/26/2018] [Indexed: 12/31/2022] Open
Abstract
Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy with a high incidence of sudden unexpected death in epilepsy (SUDEP). Most DS patients carry de novo variants in SCN1A, resulting in Nav1.1 haploinsufficiency. Because SCN1A is expressed in heart and in brain, we proposed that cardiac arrhythmia contributes to SUDEP in DS. We generated DS patient and control induced pluripotent stem cell-derived cardiac myocytes (iPSC-CMs). We observed increased sodium current (INa) and spontaneous contraction rates in DS patient iPSC-CMs versus controls. For the subject with the largest increase in INa, cardiac abnormalities were revealed upon clinical evaluation. Generation of a CRISPR gene-edited heterozygous SCN1A deletion in control iPSCs increased INa density in iPSC-CMs similar to that seen in patient cells. Thus, the high risk of SUDEP in DS may result from a predisposition to cardiac arrhythmias in addition to seizures, reflecting expression of SCN1A in heart and brain.
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Affiliation(s)
- Chad R Frasier
- Department of Pharmacology, University of Michigan Medical School, 2301E MSRB III, Ann Arbor, MI 48109, USA
| | - Helen Zhang
- Department of Neurology, University of Michigan Medical School, 5021 BSRB, Ann Arbor, MI 48109, USA
| | - James Offord
- Department of Pharmacology, University of Michigan Medical School, 2301E MSRB III, Ann Arbor, MI 48109, USA
| | - Louis T Dang
- Division of Pediatric Neurology, Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - David S Auerbach
- Department of Pharmacology, University of Michigan Medical School, 2301E MSRB III, Ann Arbor, MI 48109, USA
| | - Huilin Shi
- Department of Neurology, University of Michigan Medical School, 5021 BSRB, Ann Arbor, MI 48109, USA
| | - Chunling Chen
- Department of Pharmacology, University of Michigan Medical School, 2301E MSRB III, Ann Arbor, MI 48109, USA
| | - Alica M Goldman
- Ann Arbor VA Healthcare System, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - L Lee Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, University of Wisconsin, Madison, WI 53705, USA
| | - Vassilios J Bezzerides
- Cardiology, Electrophysiology Division, Boston Children's Hospital, Boston, MA 02115, USA
| | - Jack M Parent
- Department of Neurology, University of Michigan Medical School, 5021 BSRB, Ann Arbor, MI 48109, USA; Ann Arbor VA Healthcare System, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Lori L Isom
- Department of Pharmacology, University of Michigan Medical School, 2301E MSRB III, Ann Arbor, MI 48109, USA; Department of Neurology, University of Michigan Medical School, 5021 BSRB, Ann Arbor, MI 48109, USA.
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27
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Radwański PB, Johnson CN, Györke S, Veeraraghavan R. Cardiac Arrhythmias as Manifestations of Nanopathies: An Emerging View. Front Physiol 2018; 9:1228. [PMID: 30233404 PMCID: PMC6131669 DOI: 10.3389/fphys.2018.01228] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022] Open
Abstract
A nanodomain is a collection of proteins localized within a specialized, nanoscale structural environment, which can serve as the functional unit of macroscopic physiologic processes. We are beginning to recognize the key roles of cardiomyocyte nanodomains in essential processes of cardiac physiology such as electrical impulse propagation and excitation–contraction coupling (ECC). There is growing appreciation of nanodomain dysfunction, i.e., nanopathy, as a mechanistic driver of life-threatening arrhythmias in a variety of pathologies. Here, we offer an overview of current research on the role of nanodomains in cardiac physiology with particular emphasis on: (1) sodium channel-rich nanodomains within the intercalated disk that participate in cell-to-cell electrical coupling and (2) dyadic nanodomains located along transverse tubules that participate in ECC. The beat to beat function of cardiomyocytes involves three phases: the action potential, the calcium transient, and mechanical contraction/relaxation. In all these phases, cell-wide function results from the aggregation of the stochastic function of individual proteins. While it has long been known that proteins that exist in close proximity influence each other’s function, it is increasingly appreciated that there exist nanoscale structures that act as functional units of cardiac biophysical phenomena. Termed nanodomains, these structures are collections of proteins, localized within specialized nanoscale structural environments. The nano-environments enable the generation of localized electrical and/or chemical gradients, thereby conferring unique functional properties to these units. Thus, the function of a nanodomain is determined by its protein constituents as well as their local structural environment, adding an additional layer of complexity to cardiac biology and biophysics. However, with the emergence of experimental techniques that allow direct investigation of structure and function at the nanoscale, our understanding of cardiac physiology and pathophysiology at these scales is rapidly advancing. Here, we will discuss the structure and functions of multiple cardiomyocyte nanodomains, and novel strategies that target them for the treatment of cardiac arrhythmias.
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Affiliation(s)
- Przemysław B Radwański
- Bob and Corinne Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States.,Division of Pharmacy Practice and Science, College of Pharmacy, The Ohio State University, Columbus, OH, United States
| | - Christopher N Johnson
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Vanderbilt Center for Arrhythmia Research and Therapeutics, Nashville, TN, United States
| | - Sándor Györke
- Bob and Corinne Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Rengasayee Veeraraghavan
- Bob and Corinne Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States.,Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
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28
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Rivaud MR, Agullo-Pascual E, Lin X, Leo-Macias A, Zhang M, Rothenberg E, Bezzina CR, Delmar M, Remme CA. Sodium Channel Remodeling in Subcellular Microdomains of Murine Failing Cardiomyocytes. J Am Heart Assoc 2017; 6:e007622. [PMID: 29222390 PMCID: PMC5779058 DOI: 10.1161/jaha.117.007622] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 10/13/2017] [Indexed: 01/21/2023]
Abstract
BACKGROUND Cardiac sodium channel (NaV1.5) dysfunction contributes to arrhythmogenesis during pathophysiological conditions. Nav1.5 localizes to distinct subcellular microdomains within the cardiomyocyte, where it associates with region-specific proteins, yielding complexes whose function is location specific. We herein investigated sodium channel remodeling within distinct cardiomyocyte microdomains during heart failure. METHODS AND RESULTS Mice were subjected to 6 weeks of transverse aortic constriction (TAC; n=32) to induce heart failure. Sham-operated on mice were used as controls (n=20). TAC led to reduced left ventricular ejection fraction, QRS prolongation, increased heart mass, and upregulation of prohypertrophic genes. Whole-cell sodium current (INa) density was decreased by 30% in TAC versus sham-operated on cardiomyocytes. On macropatch analysis, INa in TAC cardiomyocytes was reduced by 50% at the lateral membrane (LM) and by 40% at the intercalated disc. Electron microscopy and scanning ion conductance microscopy revealed remodeling of the intercalated disc (replacement of [inter-]plicate regions by large foldings) and LM (less identifiable T tubules and reduced Z-groove ratios). Using scanning ion conductance microscopy, cell-attached recordings in LM subdomains revealed decreased INa and increased late openings specifically at the crest of TAC cardiomyocytes, but not in groove/T tubules. Failing cardiomyocytes displayed a denser, but more stable, microtubule network (demonstrated by increased α-tubulin and Glu-tubulin expression). Superresolution microscopy showed reduced average NaV1.5 cluster size at the LM of TAC cells, in line with reduced INa. CONCLUSIONS Heart failure induces structural remodeling of the intercalated disc, LM, and microtubule network in cardiomyocytes. These adaptations are accompanied by alterations in NaV1.5 clustering and INa within distinct subcellular microdomains of failing cardiomyocytes.
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Affiliation(s)
- Mathilde R Rivaud
- Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, the Netherlands
- Division of Cardiology, New York University Medical Center, New York, NY
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Xianming Lin
- Division of Cardiology, New York University Medical Center, New York, NY
| | | | - Mingliang Zhang
- Division of Cardiology, New York University Medical Center, New York, NY
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU-School of Medicine, New York, NY
| | - Connie R Bezzina
- Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, the Netherlands
| | - Mario Delmar
- Division of Cardiology, New York University Medical Center, New York, NY
| | - Carol Ann Remme
- Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, the Netherlands
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29
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González-Cabrera C, Meza R, Ulloa L, Merino-Sepúlveda P, Luco V, Sanhueza A, Oñate-Ponce A, Bolam JP, Henny P. Characterization of the axon initial segment of mice substantia nigra dopaminergic neurons. J Comp Neurol 2017; 525:3529-3542. [PMID: 28734032 DOI: 10.1002/cne.24288] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 07/08/2017] [Accepted: 07/10/2017] [Indexed: 12/11/2022]
Abstract
The axon initial segment (AIS) is the site of initiation of action potentials and influences action potential waveform, firing pattern, and rate. In view of the fundamental aspects of motor function and behavior that depend on the firing of substantia nigra pars compacta (SNc) dopaminergic neurons, we identified and characterized their AIS in the mouse. Immunostaining for tyrosine hydroxylase (TH), sodium channels (Nav ) and ankyrin-G (Ank-G) was used to visualize the AIS of dopaminergic neurons. Reconstructions of sampled AIS of dopaminergic neurons revealed variable lengths (12-60 μm) and diameters (0.2-0.8 μm), and an average of 50% reduction in diameter between their widest and thinnest parts. Ultrastructural analysis revealed submembranous localization of Ank-G at nodes of Ranvier and AIS. Serial ultrathin section analysis and 3D reconstructions revealed that Ank-G colocalized with TH only at the AIS. Few cases of synaptic innervation of the AIS of dopaminergic neurons were observed. mRNA in situ hybridization of brain-specific Nav subunits revealed the expression of Nav 1.2 by most SNc neurons and a small proportion expressing Nav 1.6. The presence of sodium channels, along with the submembranous location of Ank-G is consistent with the role of AIS in action potential generation. Differences in the size of the AIS likely underlie differences in firing pattern, while the tapering diameter of AIS may define a trigger zone for action potentials. Finally, the conspicuous expression of Nav 1.2 by the majority of dopaminergic neurons may explain their high threshold for firing and their low discharge rate.
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Affiliation(s)
- Cristian González-Cabrera
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo Meza
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Lorena Ulloa
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Paulina Merino-Sepúlveda
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valentina Luco
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ana Sanhueza
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alejandro Oñate-Ponce
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - J Paul Bolam
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Pablo Henny
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Veeraraghavan R, Györke S, Radwański PB. Neuronal sodium channels: emerging components of the nano-machinery of cardiac calcium cycling. J Physiol 2017; 595:3823-3834. [PMID: 28195313 DOI: 10.1113/jp273058] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/05/2016] [Indexed: 01/07/2023] Open
Abstract
Excitation-contraction coupling is the bridge between cardiac electrical activation and mechanical contraction. It is driven by the influx of Ca2+ across the sarcolemma triggering Ca2+ release from the sarcoplasmic reticulum (SR) - a process termed Ca2+ -induced Ca2+ release (CICR) - followed by re-sequestration of Ca2+ into the SR. The Na+ /Ca2+ exchanger inextricably couples the cycling of Ca2+ and Na+ in cardiac myocytes. Thus, influx of Na+ via voltage-gated Na+ channels (NaV ) has emerged as an important regulator of CICR both in health and in disease. Recent insights into the subcellular distribution of cardiac and neuronal NaV isoforms and their ultrastructural milieu have important implications for the roles of these channels in mediating Ca2+ -driven arrhythmias. This review will discuss functional insights into the role of neuronal NaV isoforms vis-à-vis cardiac NaV s in triggering such arrhythmias and their potential as therapeutic targets in the context of the aforementioned structural observations.
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Affiliation(s)
- Rengasayee Veeraraghavan
- Virginia Tech Carilion Research Institute, and Center for Heart and Regenerative Medicine, Virginia Polytechnic University, Roanoke, VA, USA
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 510, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, USA
| | - Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 510, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, USA.,Division of Pharmacy Practice and Science, College of Pharmacy, Ohio State University, Columbus, OH, USA
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Cardiac arrhythmia in a mouse model of sodium channel SCN8A epileptic encephalopathy. Proc Natl Acad Sci U S A 2016; 113:12838-12843. [PMID: 27791149 DOI: 10.1073/pnas.1612746113] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Patients with early infantile epileptic encephalopathy (EIEE) are at increased risk for sudden unexpected death in epilepsy (SUDEP). De novo mutations of the sodium channel gene SCN8A, encoding the sodium channel Nav1.6, result in EIEE13 (OMIM 614558), which has a 10% risk of SUDEP. Here, we investigated the cardiac phenotype of a mouse model expressing the gain of function EIEE13 patient mutation p.Asn1768Asp in Scn8a (Nav1.6-N1768D). We tested Scn8aN1768D/+ mice for alterations in cardiac excitability. We observed prolongation of the early stages of action potential (AP) repolarization in mutant myocytes vs. controls. Scn8aN1768D/+ myocytes were hyperexcitable, with a lowered threshold for AP firing, increased incidence of delayed afterdepolarizations, increased calcium transient duration, increased incidence of diastolic calcium release, and ectopic contractility. Calcium transient duration and diastolic calcium release in the mutant myocytes were tetrodotoxin-sensitive. A selective inhibitor of reverse mode Na/Ca exchange blocked the increased incidence of diastolic calcium release in mutant cells. Scn8aN1768D/+ mice exhibited bradycardia compared with controls. This difference in heart rate dissipated after administration of norepinephrine, and there were no differences in heart rate in denervated ex vivo hearts, implicating parasympathetic hyperexcitability in the Scn8aN1768D/+ animals. When challenged with norepinephrine and caffeine to simulate a catecholaminergic surge, Scn8aN1768D/+ mice showed ventricular arrhythmias. Two of three mutant mice under continuous ECG telemetry recording experienced death, with severe bradycardia preceding asystole. Thus, in addition to central neuron hyperexcitability, Scn8aN1768D/+ mice have cardiac myoycte and parasympathetic neuron hyperexcitability. Simultaneous dysfunction in these systems may contribute to SUDEP associated with mutations of Scn8a.
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McKinnon D, Rosati B. Transmural gradients in ion channel and auxiliary subunit expression. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:165-186. [PMID: 27702655 DOI: 10.1016/j.pbiomolbio.2016.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/30/2016] [Indexed: 12/11/2022]
Abstract
Evolution has acted to shape the action potential in different regions of the heart in order to produce a maximally stable and efficient pump. This has been achieved by creating regional differences in ion channel expression levels within the heart as well as differences between equivalent cardiac tissues in different species. These region- and species-dependent differences in channel expression are established by regulatory evolution, evolution of the regulatory mechanisms that control channel expression levels. Ion channel auxiliary subunits are obvious targets for regulatory evolution, in order to change channel expression levels and/or modify channel function. This review focuses on the transmural gradients of ion channel expression in the heart and the role that regulation of auxiliary subunit expression plays in generating and shaping these gradients.
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Affiliation(s)
- David McKinnon
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Barbara Rosati
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.
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Xu Q, Patel D, Zhang X, Veenstra RD. Changes in cardiac Nav1.5 expression, function, and acetylation by pan-histone deacetylase inhibitors. Am J Physiol Heart Circ Physiol 2016; 311:H1139-H1149. [PMID: 27638876 DOI: 10.1152/ajpheart.00156.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/24/2016] [Indexed: 12/19/2022]
Abstract
Histone deacetylase (HDAC) inhibitors are small molecule anticancer therapeutics that exhibit limiting cardiotoxicities including QT interval prolongation and life-threatening cardiac arrhythmias. Because the molecular mechanisms for HDAC inhibitor-induced cardiotoxicity are poorly understood, we performed whole cell patch voltage-clamp experiments to measure cardiac sodium currents (INa) from wild-type neonatal mouse ventricular or human-induced pluripotent stem cell-derived cardiomyocytes treated with trichostatin A (TSA), vorinostat (VOR), or romidepsin (FK228). All three pan-HDAC inhibitors dose dependently decreased peak INa density and shifted the voltage activation curve 3- to 8-mV positive. Increases in late INa were not observed despite a moderate slowing of the inactivation rate at low activating potentials (<-40 mV). Scn5a mRNA levels were not significantly altered but NaV1.5 protein levels were significantly reduced. Immunoprecipitation with anti-NaV1.5 and Western blotting with anti-acetyl-lysine antibodies indicated that NaV1.5 acetylation is increased in vivo after HDAC inhibition. FK228 inhibited total cardiac HDAC activity with two apparent IC50s of 5 nM and 1.75 μM, consistent with previous findings with TSA and VOR. FK228 also decreased ventricular gap junction conductance (gj), again consistent with previous findings. We conclude that pan-HDAC inhibition reduces cardiac INa density and NaV1.5 protein levels without affecting late INa amplitude and, thus, probably does not contribute to the reported QT interval prolongation and arrhythmias associated with pan-HDAC inhibitor therapies. Conversely, reductions in gj may enhance the occurrence of triggered activity by limiting electrotonic inhibition and, combined with reduced INa, slow myocardial conduction and increase vulnerability to reentrant arrhythmias.
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Affiliation(s)
- Qin Xu
- Department of Pharmacology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York; and
| | - Dakshesh Patel
- Department of Pharmacology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York; and
| | - Xian Zhang
- Department of Pharmacology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York; and
| | - Richard D Veenstra
- Department of Pharmacology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York; and .,Department of Cell and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York
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Abstract
The aim of this review is to provide the reader with a synopsis of some of the emerging ideas and experimental findings in cardiac physiology and pathophysiology that were published in 2015. To provide context for the non-specialist, a brief summary of cardiac contraction and calcium (Ca) regulation in the heart in health and disease is provided. Thereafter, some recently published articles are introduced that indicate the current thinking on (1) the Ca regulatory pathways modulated by Ca/calmodulin-dependent protein kinase II, (2) the potential influences of nitrosylation by nitric oxide or S-nitrosated proteins, (3) newly observed effects of reactive oxygen species (ROS) on contraction and Ca regulation following myocardial infarction and a possible link with changes in mitochondrial Ca, and (4) the effects of some of these signaling pathways on late Na current and pro-arrhythmic afterdepolarizations as well as the effects of transverse tubule disturbances.
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Affiliation(s)
- Ken T MacLeod
- Faculty of Medicine, National Heart & Lung Institute, Imperial College London, London, UK
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Meisler MH, Helman G, Hammer MF, Fureman BE, Gaillard WD, Goldin AL, Hirose S, Ishii A, Kroner BL, Lossin C, Mefford HC, Parent JM, Patel M, Schreiber J, Stewart R, Whittemore V, Wilcox K, Wagnon JL, Pearl PL, Vanderver A, Scheffer IE. SCN8A encephalopathy: Research progress and prospects. Epilepsia 2016; 57:1027-35. [PMID: 27270488 PMCID: PMC5495462 DOI: 10.1111/epi.13422] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2016] [Indexed: 01/15/2023]
Abstract
On April 21, 2015, the first SCN8A Encephalopathy Research Group convened in Washington, DC, to assess current research into clinical and pathogenic features of the disorder and prepare an agenda for future research collaborations. The group comprised clinical and basic scientists and representatives of patient advocacy groups. SCN8A encephalopathy is a rare disorder caused by de novo missense mutations of the sodium channel gene SCN8A, which encodes the neuronal sodium channel Nav 1.6. Since the initial description in 2012, approximately 140 affected individuals have been reported in publications or by SCN8A family groups. As a result, an understanding of the severe impact of SCN8A mutations is beginning to emerge. Defining a genetic epilepsy syndrome goes beyond identification of molecular etiology. Topics discussed at this meeting included (1) comparison between mutations of SCN8A and the SCN1A mutations in Dravet syndrome, (2) biophysical properties of the Nav 1.6 channel, (3) electrophysiologic effects of patient mutations on channel properties, (4) cell and animal models of SCN8A encephalopathy, (5) drug screening strategies, (6) the phenotypic spectrum of SCN8A encephalopathy, and (7) efforts to develop a bioregistry. A panel discussion of gaps in bioregistry, biobanking, and clinical outcomes data was followed by a planning session for improved integration of clinical and basic science research. Although SCN8A encephalopathy was identified only recently, there has been rapid progress in functional analysis and phenotypic classification. The focus is now shifting from identification of the underlying molecular cause to the development of strategies for drug screening and prioritized patient care.
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Affiliation(s)
- Miriam H. Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, U.S.A
| | - Guy Helman
- Department of Neurology, Children’s National Health System, Washington, District of Columbia, U.S.A
- Center for Genetic Medicine Research, Children’s National Health System, Washington, District of Columbia, U.S.A
| | - Michael F. Hammer
- ARL Division of Biotechnology, University of Arizona, Tucson, Arizona, U.S.A
| | - Brandy E. Fureman
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - William D. Gaillard
- Department of Neurology, Children’s National Health System, Washington, District of Columbia, U.S.A
- Center for Neuroscience Research, Children’s National Health System, Washington, District of Columbia, U.S.A
| | - Alan L. Goldin
- Microbiology & Molecular Genetics and Anatomy & Neurobiology, University of California, Irvine, California, U.S.A
| | - Shinichi Hirose
- Department of Pediatrics, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Atsushi Ishii
- Department of Pediatrics, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Barbara L. Kroner
- Biostatistics and Epidemiology, RTI International, Rockville, Maryland, U.S.A
| | - Christoph Lossin
- Department of Neurology, School of Medicine, University of California Davis, Sacramento, California, U.S.A
| | - Heather C. Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, U.S.A
| | - Jack M. Parent
- Department of Neurology, University of Michigan Medical Center and VA Ann Arbor Healthcare System, Ann Arbor, Michigan, U.S.A
| | - Manoj Patel
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, Virginia, U.S.A
| | - John Schreiber
- Department of Neurology, Children’s National Health System, Washington, District of Columbia, U.S.A
| | - Randall Stewart
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Vicky Whittemore
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Karen Wilcox
- Anticonvulsant Drug Development Program, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, U.S.A
| | - Jacy L Wagnon
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, U.S.A
| | - Phillip L. Pearl
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Adeline Vanderver
- Department of Neurology, Children’s National Health System, Washington, District of Columbia, U.S.A
- Center for Genetic Medicine Research, Children’s National Health System, Washington, District of Columbia, U.S.A
- Department of Integrated Systems Biology and Pediatrics, George Washington University, Washington, District of Columbia, U.S.A
| | - Ingrid E. Scheffer
- Department of Neurology, Royal Children’s Hospital, Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
- Florey Institute of Neurosciences and Mental Health, Melbourne, Victoria, Australia
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Radwański PB, Ho HT, Veeraraghavan R, Brunello L, Liu B, Belevych AE, Unudurthi SD, Makara MA, Priori SG, Volpe P, Armoundas AA, Dillmann WH, Knollmann BC, Mohler PJ, Hund TJ, Györke S. Neuronal Na + Channels Are Integral Components of Pro-arrhythmic Na +/Ca 2+ Signaling Nanodomain That Promotes Cardiac Arrhythmias During β-adrenergic Stimulation. JACC Basic Transl Sci 2016; 1:251-266. [PMID: 27747307 PMCID: PMC5065245 DOI: 10.1016/j.jacbts.2016.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Cardiac arrhythmias are a leading cause of death in the US. Vast majority of these arrhythmias including catecholaminergic polymorphic ventricular tachycardia (CPVT) are associated with increased levels of circulating catecholamines and involve abnormal impulse formation secondary to aberrant Ca2+ and Na+ handling. However, the mechanistic link between β-AR stimulation and the subcellular/molecular arrhythmogenic trigger(s) remains elusive. METHODS AND RESULTS We performed functional and structural studies to assess Ca2+ and Na+ signaling in ventricular myocyte as well as surface electrocardiograms in mouse models of cardiac calsequestrin (CASQ2)-associated CPVT. We demonstrate that a subpopulation of Na+ channels (neuronal Na+ channels; nNav) that colocalize with RyR2 and Na+/Ca2+ exchanger (NCX) are a part of the β-AR-mediated arrhythmogenic process. Specifically, augmented Na+ entry via nNav in the settings of genetic defects within the RyR2 complex and enhanced sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA)-mediated SR Ca2+ refill is both an essential and a necessary factor for the arrhythmogenesis. Furthermore, we show that augmentation of Na+ entry involves β-AR-mediated activation of CAMKII subsequently leading to nNav augmentation. Importantly, selective pharmacological inhibition as well as silencing of Nav1.6 inhibit myocyte arrhythmic potential and prevent arrhythmias in vivo. CONCLUSION These data suggest that the arrhythmogenic alteration in Na+/Ca2+ handling evidenced ruing β-AR stimulation results, at least in part, from enhanced Na+ influx through nNav. Therefore, selective inhibition of these channels and Nav1.6 in particular can serve as a potential antiarrhythmic therapy.
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Affiliation(s)
- Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US ; Division of Pharmacy Practice and Sciences, College of Pharmacy, The Ohio State University, Columbus, OH, US
| | - Hsiang-Ting Ho
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Rengasayee Veeraraghavan
- Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, VA, USA
| | - Lucia Brunello
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Bin Liu
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Andriy E Belevych
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Sathya D Unudurthi
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Michael A Makara
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Silvia G Priori
- Division of Cardiology and Molecular Cardiology, Maugeri Foundation-University of Pavia, Pavia, Italy
| | - Pompeo Volpe
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA, USA
| | - Wolfgang H Dillmann
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University Medical School, Nashville, TN, USA
| | - Peter J Mohler
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Thomas J Hund
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, VA, USA
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
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Liu M, Yang KC, Dudley SC. Cardiac Sodium Channel Mutations: Why so Many Phenotypes? CURRENT TOPICS IN MEMBRANES 2016; 78:513-59. [PMID: 27586294 DOI: 10.1016/bs.ctm.2015.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cardiac Na(+) channel (Nav1.5) conducts a depolarizing inward Na(+) current that is responsible for the generation of the upstroke Phase 0 of the action potential. In heart tissue, changes in Na(+) currents can affect conduction velocity and impulse propagation. The cardiac Nav1.5 is also involved in determination of the action potential duration, since some channels may reopen during the plateau phase, generating a persistent or late inward current. Mutations of cardiac Nav1.5 can induce gain or loss of channel function because of an increased late current or a decrease of peak current, respectively. Gain-of-function mutations cause Long QT syndrome type 3 and possibly atrial fibrillation, while loss-of-function channel mutations are associated with a wider variety of phenotypes, such as Brugada syndrome, cardiac conduction disease, dilated cardiomyopathy, and sick sinus node syndrome. The penetrance and phenotypes resulting from Nav1.5 mutations also vary with age, gender, body temperature, circadian rhythm, and between regions of the heart. This phenotypic variability makes it difficult to correlate genotype-phenotype. We propose that mutations are only one contributor to the phenotype and additional modifications on Nav1.5 lead to the phenotypic variability. Possible modifiers include other genetic variations and alterations in the life cycle of Nav1.5 such as gene transcription, RNA processing, translation, posttranslational modifications, trafficking, complex assembly, and degradation. In this chapter, we summarize potential modifiers of cardiac Nav1.5 that could help explain the clinically observed phenotypic variability. Consideration of these modifiers could help improve genotype-phenotype correlations and lead to new therapeutic strategies.
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Affiliation(s)
- M Liu
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - K-C Yang
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - S C Dudley
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
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Unudurthi SD, Hund TJ. Late sodium current dysregulation as a causal factor in arrhythmia. Expert Rev Cardiovasc Ther 2016; 14:545-7. [PMID: 26886049 DOI: 10.1586/14779072.2016.1155451] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sathya D Unudurthi
- a The Dorothy M. Davis Heart and Lung Research Institute.,b Department of Biomedical Engineering , College of Engineering, The Ohio State University , Columbus , OH , USA
| | - Thomas J Hund
- a The Dorothy M. Davis Heart and Lung Research Institute.,c Department of Biomedical Engineering , College of Engineering.,d Department of Internal Medicine , The Ohio State University.,e Wexner Medical Center, The Ohio State University , Columbus , OH , USA
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40
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Bers DM, Chen-Izu Y. Sodium and calcium regulation in cardiac myocytes: from molecules to heart failure and arrhythmia. J Physiol 2015; 593:1327-9. [PMID: 25772288 DOI: 10.1113/jp270133] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
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Roger S, Gillet L, Le Guennec JY, Besson P. Voltage-gated sodium channels and cancer: is excitability their primary role? Front Pharmacol 2015; 6:152. [PMID: 26283962 PMCID: PMC4518325 DOI: 10.3389/fphar.2015.00152] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/09/2015] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (NaV) are molecular characteristics of excitable cells. Their activation, triggered by membrane depolarization, generates transient sodium currents that initiate action potentials in neurons and muscle cells. Sodium currents were discovered by Hodgkin and Huxley using the voltage clamp technique and reported in their landmark series of papers in 1952. It was only in the 1980's that sodium channel proteins from excitable membranes were molecularly characterized by Catterall and his collaborators. Non-excitable cells can also express NaV channels in physiological conditions as well as in pathological conditions. These NaV channels can sustain biological roles that are not related to the generation of action potentials. Interestingly, it is likely that the abnormal expression of NaV in pathological tissues can reflect the re-expression of a fetal phenotype. This is especially true in epithelial cancer cells for which these channels have been identified and sodium currents recorded, while it was not the case for cells from the cognate normal tissues. In cancers, the functional activity of NaV appeared to be involved in regulating the proliferative, migrative, and invasive properties of cells. This review is aimed at addressing the non-excitable roles of NaV channels with a specific emphasis in the regulation of cancer cell biology.
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Affiliation(s)
- Sébastien Roger
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours Tours, France ; Département de Physiologie Animale, UFR Sciences and Techniques, Université François-Rabelais de Tours Tours, France
| | - Ludovic Gillet
- Department of Clinical Research, University of Bern Bern, Switzerland
| | | | - Pierre Besson
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours Tours, France
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Makielski JC. Late sodium current: A mechanism for angina, heart failure, and arrhythmia. Trends Cardiovasc Med 2015; 26:115-22. [PMID: 26092781 DOI: 10.1016/j.tcm.2015.05.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/01/2015] [Accepted: 05/17/2015] [Indexed: 11/25/2022]
Abstract
The peak sodium current underlies excitability and conduction in heart muscle, but a late sodium current flowing after the peak contributes to maintaining and prolonging the action potential plateau, and also to intracellular sodium loading, which in turn increases intracellular calcium with consequent effects on arrhythmia and diastolic function. Late sodium current is pathologically increased in both genetic and acquired heart disease, making it an attractive target for therapy to treat arrhythmia, heart failure, and angina. This review provides an overview of the underlying bases for the clinical implications of late sodium current block.
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Affiliation(s)
- Jonathan C Makielski
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, WI.
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A novel mechanism for the treatment of angina, arrhythmias, and diastolic dysfunction: inhibition of late I(Na) using ranolazine. J Cardiovasc Pharmacol 2010; 54:279-86. [PMID: 19333133 DOI: 10.1097/fjc.0b013e3181a1b9e7] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Inhibition of the persistent or late Na current (INa) using ranolazine (Ranexa) represents a novel mechanism of action that was approved in the United States in 2006 and only recently in the European Union for use in patients with stable angina pectoris. In general, myocardial ischemia is associated with reduced adenosine triphosphate fluxes and decreased energy supply, resulting in severe disturbances of intracellular ion homeostasis in cardiac myocytes. In the recent years, increased late INa was suggested to contribute to this phenomenon by elevating intracellular Na concentration with subsequent rise in diastolic Ca levels by means of the sarcolemmal Na-Ca exchange system. Ranolazine, a specific inhibitor of late INa, reduces Na influx and hence ameliorates disturbed Na and Ca homeostasis. This is associated with a symptomatic improvement of angina in patients unlike other antianginal drugs without affecting heart rate or systemic blood pressure as shown in placebo-controlled studies. Therefore, ranolazine is a useful new option for patients with chronic stable angina not only as an add-on therapy. New clinical and experimental studies even point to potential antiarrhythmic effects, beneficial effects in diastolic heart failure, and under hyperglycemic conditions. In the present article, the relevant pathophysiological concepts for the role of late INa inhibition are reviewed and the most recent data from basic studies and clinical trials are summarized.
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