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Li E, van der Heyden MAG. The network of cardiac K IR2.1: its function, cellular regulation, electrical signaling, diseases and new drug avenues. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:6369-6389. [PMID: 38683369 PMCID: PMC11422472 DOI: 10.1007/s00210-024-03116-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
The functioning of the human heart relies on complex electrical and communication systems that coordinate cardiac contractions and sustain rhythmicity. One of the key players contributing to this intricate system is the KIR2.1 potassium ion channel, which is encoded by the KCNJ2 gene. KIR2.1 channels exhibit abundant expression in both ventricular myocytes and Purkinje fibers, exerting an important role in maintaining the balance of intracellular potassium ion levels within the heart. And by stabilizing the resting membrane potential and contributing to action potential repolarization, these channels have an important role in cardiac excitability also. Either gain- or loss-of-function mutations, but also acquired impairments of their function, are implicated in the pathogenesis of diverse types of cardiac arrhythmias. In this review, we aim to elucidate the system functions of KIR2.1 channels related to cellular electrical signaling, communication, and their contributions to cardiovascular disease. Based on this knowledge, we will discuss existing and new pharmacological avenues to modulate their function.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands.
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Kohajda Z, Corici C, Kristóf A, Virág L, Husti Z, Baczkó I, Sághy L, Varró A, Jost N. The Properties of the Transient Outward, Inward Rectifier and Acetylcholine-Sensitive Potassium Currents in Atrial Myocytes from Dogs in Sinus Rhythm and Experimentally Induced Atrial Fibrillation Dog Models. Pharmaceuticals (Basel) 2024; 17:1138. [PMID: 39338302 PMCID: PMC11434634 DOI: 10.3390/ph17091138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 07/26/2024] [Accepted: 08/27/2024] [Indexed: 09/30/2024] Open
Abstract
AIMS Atrial fibrillation (AF) is the most common chronic/recurrent arrhythmia, which significantly impairs quality of life and increases cardiovascular morbidity and mortality. Therefore, the aim of the present study was to investigate the properties of three repolarizing potassium currents which were shown to contribute to AF-induced electrical remodeling, i.e., the transient outward (Ito), inward rectifier (IK1) and acetylcholine-sensitive (IK,ACh) potassium currents in isolated atrial myocytes obtained from dogs either with sinus rhythm (SR) or following chronic atrial tachypacing (400/min)-induced AF. METHODS Atrial remodeling and AF were induced by chronic (4-6 weeks of) right atrial tachypacing (400/min) in dogs. Transmembrane ionic currents were measured by applying the whole-cell patch-clamp technique at 37 °C. RESULTS The Ito current was slightly downregulated in AF cells when compared with that recorded in SR cells. This downregulation was also associated with slowed inactivation kinetics. The IK1 current was found to be larger in AF cells; however, this upregulation was not statistically significant in the voltage range corresponding with atrial action potential (-80 mV to 0 mV). IK,ACh was activated by the cholinergic agonist carbachol (CCh; 2 µM). In SR, CCh activated a large current either in inward or outward directions. The selective IK,ACh inhibitor tertiapin (10 nM) blocked the outward CCh-induced current by 61%. In atrial cardiomyocytes isolated from dogs with AF, the presence of a constitutively active IK,ACh was observed, blocked by 59% with 10 nM tertiapin. However, in "AF atrial myocytes", CCh activated an additional, significant ligand-dependent and tertiapin-sensitive IK,ACh current. CONCLUSIONS In our dog AF model, Ito unlike in humans was downregulated only in a slight manner. Due to its slow inactivation kinetics, it seems that Ito may play a more significant role in atrial repolarization than in ventricular working muscle myocytes. The presence of the constitutively active IK,ACh in atrial myocytes from AF dogs shows that electrical remodeling truly developed in this model. The IK,ACh current (both ligand-dependent and constitutively active) seems to play a significant role in canine atrial electrical remodeling and may be a promising atrial selective drug target for suppressing AF.
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Affiliation(s)
- Zsófia Kohajda
- HUN-REN-SZTE Research Group of Cardiovascular Pharmacology, H-6701 Szeged, Hungary
| | - Claudia Corici
- Department of Pharmacology & Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 12, P.O. Box 427, H-6701 Szeged, Hungary (I.B.)
| | - Attila Kristóf
- Department of Pharmacology & Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 12, P.O. Box 427, H-6701 Szeged, Hungary (I.B.)
| | - László Virág
- Department of Pharmacology & Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 12, P.O. Box 427, H-6701 Szeged, Hungary (I.B.)
- Pharmaceutical and Medical Device Developments Competence Centre of the Life Sciences Cluster, Centre of Excellence for Interdisciplinary Research, Development and Innovation, University of Szeged, H-6701 Szeged, Hungary
| | - Zoltán Husti
- Department of Pharmacology & Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 12, P.O. Box 427, H-6701 Szeged, Hungary (I.B.)
| | - István Baczkó
- Department of Pharmacology & Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 12, P.O. Box 427, H-6701 Szeged, Hungary (I.B.)
- Pharmaceutical and Medical Device Developments Competence Centre of the Life Sciences Cluster, Centre of Excellence for Interdisciplinary Research, Development and Innovation, University of Szeged, H-6701 Szeged, Hungary
| | - László Sághy
- Cardiac Electrophysiology Division, Department of Internal Medicine, Albert Szent-Györgyi Medical School, University of Szeged, H-6701 Szeged, Hungary
| | - András Varró
- HUN-REN-SZTE Research Group of Cardiovascular Pharmacology, H-6701 Szeged, Hungary
- Department of Pharmacology & Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 12, P.O. Box 427, H-6701 Szeged, Hungary (I.B.)
- Pharmaceutical and Medical Device Developments Competence Centre of the Life Sciences Cluster, Centre of Excellence for Interdisciplinary Research, Development and Innovation, University of Szeged, H-6701 Szeged, Hungary
| | - Norbert Jost
- HUN-REN-SZTE Research Group of Cardiovascular Pharmacology, H-6701 Szeged, Hungary
- Department of Pharmacology & Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 12, P.O. Box 427, H-6701 Szeged, Hungary (I.B.)
- Pharmaceutical and Medical Device Developments Competence Centre of the Life Sciences Cluster, Centre of Excellence for Interdisciplinary Research, Development and Innovation, University of Szeged, H-6701 Szeged, Hungary
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Gutiérrez LK, Moreno-Manuel AI, Jalife J. Kir2.1-Na V1.5 channelosome and its role in arrhythmias in inheritable cardiac diseases. Heart Rhythm 2024; 21:630-646. [PMID: 38244712 DOI: 10.1016/j.hrthm.2024.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/22/2024]
Abstract
Sudden cardiac death in children and young adults is a relatively rare but tragic event whose pathophysiology is unknown at the molecular level. Evidence indicates that the main cardiac sodium channel (NaV1.5) and the strong inward rectifier potassium channel (Kir2.1) physically interact and form macromolecular complexes (channelosomes) with common partners, including adapter, scaffolding, and regulatory proteins that help them traffic together to their eventual membrane microdomains. Most important, dysfunction of either or both ion channels has direct links to hereditary human diseases. For example, certain mutations in the KCNJ2 gene encoding the Kir2.1 protein result in Andersen-Tawil syndrome type 1 and alter both inward rectifier potassium and sodium inward currents. Similarly, trafficking-deficient mutations in the gene encoding the NaV1.5 protein (SCN5A) result in Brugada syndrome and may also disturb both inward rectifier potassium and sodium inward currents. Moreover, gain-of-function mutations in KCNJ2 result in short QT syndrome type 3, which is extremely rare but highly arrhythmogenic, and can modify Kir2.1-NaV1.5 interactions in a mutation-specific way, further highlighting the relevance of channelosomes in ion channel diseases. By expressing mutant proteins that interrupt or modify Kir2.1 or NaV1.5 function in animal models and patient-specific pluripotent stem cell-derived cardiomyocytes, investigators are defining for the first time the mechanistic framework of how mutation-induced dysregulation of the Kir2.1-NaV1.5 channelosome affects cardiac excitability, resulting in arrhythmias and sudden death in different cardiac diseases.
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Affiliation(s)
- Lilian K Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | | | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain; Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.
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Ferreira G, Santander A, Cardozo R, Chavarría L, Domínguez L, Mujica N, Benítez M, Sastre S, Sobrevia L, Nicolson GL. Nutrigenomics of inward rectifier potassium channels. Biochim Biophys Acta Mol Basis Dis 2023:166803. [PMID: 37406972 DOI: 10.1016/j.bbadis.2023.166803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
Inwardly rectifying potassium (Kir) channels play a key role in maintaining the resting membrane potential and supporting potassium homeostasis. There are many variants of Kir channels, which are usually tetramers in which the main subunit has two trans-membrane helices attached to two N- and C-terminal cytoplasmic tails with a pore-forming loop in between that contains the selectivity filter. These channels have domains that are strongly modulated by molecules present in nutrients found in different diets, such as phosphoinositols, polyamines and Mg2+. These molecules can impact these channels directly or indirectly, either allosterically by modulation of enzymes or via the regulation of channel expression. A particular type of these channels is coupled to cell metabolism and inhibited by ATP (KATP channels, essential for insulin release and for the pathogenesis of metabolic diseases like diabetes mellitus). Genomic changes in Kir channels have a significant impact on metabolism, such as conditioning the nutrients and electrolytes that an individual can take. Thus, the nutrigenomics of ion channels is an important emerging field in which we are attempting to understand how nutrients and diets can affect the activity and expression of ion channels and how genomic changes in such channels may be the basis for pathological conditions that limit nutrition and electrolyte intake. In this contribution we briefly review Kir channels, discuss their nutrigenomics, characterize how different components in the diet affect their function and expression, and suggest how their genomic changes lead to pathological phenotypes that affect diet and electrolyte intake.
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Affiliation(s)
- Gonzalo Ferreira
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay.
| | - Axel Santander
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Romina Cardozo
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Luisina Chavarría
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Lucía Domínguez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Nicolás Mujica
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Milagros Benítez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Santiago Sastre
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo CP 11800, Uruguay
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; Medical School (Faculty of Medicine), Sao Paulo State University (UNESP), Brazil; University of Queensland, Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, 4029, Queensland, Australia; Tecnologico de Monterrey, Eutra, The Institute for Obesity Research (IOR), School of Medicine and Health Sciences, Monterrey, Nuevo León, Mexico
| | - Garth L Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA, USA
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Markandeya YS, Gregorich ZR, Feng L, Ramchandran V, O' Hara T, Vaidyanathan R, Mansfield C, Keefe AM, Beglinger CJ, Best JM, Kalscheur MM, Lea MR, Hacker TA, Gorelik J, Trayanova NA, Eckhardt LL, Makielski JC, Balijepalli RC, Kamp TJ. Caveolin-3 and Caveolae regulate ventricular repolarization. J Mol Cell Cardiol 2023; 177:38-49. [PMID: 36842733 PMCID: PMC10065933 DOI: 10.1016/j.yjmcc.2023.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 02/03/2023] [Accepted: 02/21/2023] [Indexed: 02/28/2023]
Abstract
RATIONALE Flask-shaped invaginations of the cardiomyocyte sarcolemma called caveolae require the structural protein caveolin-3 (Cav-3) and host a variety of ion channels, transporters, and signaling molecules. Reduced Cav-3 expression has been reported in models of heart failure, and variants in CAV3 have been associated with the inherited long-QT arrhythmia syndrome. Yet, it remains unclear whether alterations in Cav-3 levels alone are sufficient to drive aberrant repolarization and increased arrhythmia risk. OBJECTIVE To determine the impact of cardiac-specific Cav-3 ablation on the electrophysiological properties of the adult mouse heart. METHODS AND RESULTS Cardiac-specific, inducible Cav3 homozygous knockout (Cav-3KO) mice demonstrated a marked reduction in Cav-3 expression by Western blot and loss of caveolae by electron microscopy. However, there was no change in macroscopic cardiac structure or contractile function. The QTc interval was increased in Cav-3KO mice, and there was an increased propensity for ventricular arrhythmias. Ventricular myocytes isolated from Cav-3KO mice exhibited a prolonged action potential duration (APD) that was due to reductions in outward potassium currents (Ito, Iss) and changes in inward currents including slowed inactivation of ICa,L and increased INa,L. Mathematical modeling demonstrated that the changes in the studied ionic currents were adequate to explain the prolongation of the mouse ventricular action potential. Results from human iPSC-derived cardiomyocytes showed that shRNA knockdown of Cav-3 similarly prolonged APD. CONCLUSION We demonstrate that Cav-3 and caveolae regulate cardiac repolarization and arrhythmia risk via the integrated modulation of multiple ionic currents.
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Affiliation(s)
- Yogananda S Markandeya
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA; National Institute of Mental Health and Neuroscience, Bengaluru, India
| | - Zachery R Gregorich
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Li Feng
- Department of Cardiology, Beijing Anzhen Hospital, Captial Medical University, National Clinical Research Center for Cardiovascular Diseases, Beijing, China
| | - Vignesh Ramchandran
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Thomas O' Hara
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Ravi Vaidyanathan
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Catherine Mansfield
- National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Alexis M Keefe
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Carl J Beglinger
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Jabe M Best
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Matthew M Kalscheur
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Martin R Lea
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Timothy A Hacker
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Julia Gorelik
- National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Natalia A Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Jonathan C Makielski
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Ravi C Balijepalli
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA
| | - Timothy J Kamp
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin Madison, WI, USA.
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Li E, Kool W, Woolschot L, van der Heyden MAG. Chronic Propafenone Application Increases Functional K IR2.1 Expression In Vitro. Pharmaceuticals (Basel) 2023; 16:ph16030404. [PMID: 36986503 PMCID: PMC10056987 DOI: 10.3390/ph16030404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 03/30/2023] Open
Abstract
Expression and activity of inwardly rectifying potassium (KIR) channels within the heart are strictly regulated. KIR channels have an important role in shaping cardiac action potentials, having a limited conductance at depolarized potentials but contributing to the final stage of repolarization and resting membrane stability. Impaired KIR2.1 function causes Andersen-Tawil Syndrome (ATS) and is associated with heart failure. Restoring KIR2.1 function by agonists of KIR2.1 (AgoKirs) would be beneficial. The class 1c antiarrhythmic drug propafenone is identified as an AgoKir; however, its long-term effects on KIR2.1 protein expression, subcellular localization, and function are unknown. Propafenone's long-term effect on KIR2.1 expression and its underlying mechanisms in vitro were investigated. KIR2.1-carried currents were measured by single-cell patch-clamp electrophysiology. KIR2.1 protein expression levels were determined by Western blot analysis, whereas conventional immunofluorescence and advanced live-imaging microscopy were used to assess the subcellular localization of KIR2.1 proteins. Acute propafenone treatment at low concentrations supports the ability of propafenone to function as an AgoKir without disturbing KIR2.1 protein handling. Chronic propafenone treatment (at 25-100 times higher concentrations than in the acute treatment) increases KIR2.1 protein expression and KIR2.1 current densities in vitro, which are potentially associated with pre-lysosomal trafficking inhibition.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Willy Kool
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Liset Woolschot
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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Averin AS, Konakov MV, Pimenov OY, Galimova MH, Berezhnov AV, Nenov MN, Dynnik VV. Regulation of Papillary Muscle Contractility by NAD and Ammonia Interplay: Contribution of Ion Channels and Exchangers. MEMBRANES 2022; 12:1239. [PMID: 36557146 PMCID: PMC9785361 DOI: 10.3390/membranes12121239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/04/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
Various models, including stem cells derived and isolated cardiomyocytes with overexpressed channels, are utilized to analyze the functional interplay of diverse ion currents involved in cardiac automaticity and excitation-contraction coupling control. Here, we used β-NAD and ammonia, known hyperpolarizing and depolarizing agents, respectively, and applied inhibitory analysis to reveal the interplay of several ion channels implicated in rat papillary muscle contractility control. We demonstrated that: 4 mM β-NAD, having no strong impact on resting membrane potential (RMP) and action potential duration (APD90) of ventricular cardiomyocytes, evoked significant suppression of isometric force (F) of paced papillary muscle. Reactive blue 2 restored F to control values, suggesting the involvement of P2Y-receptor-dependent signaling in β-NAD effects. Meantime, 5 mM NH4Cl did not show any effect on F of papillary muscle but resulted in significant RMP depolarization, APD90 shortening, and a rightward shift of I-V relationship for total steady state currents in cardiomyocytes. Paradoxically, NH4Cl, being added after β-NAD and having no effect on RMP, APD, and I-V curve, recovered F to the control values, indicating β-NAD/ammonia antagonism. Blocking of HCN, Kir2.x, and L-type calcium channels, Ca2+-activated K+ channels (SK, IK, and BK), or NCX exchanger reverse mode prevented this effect, indicating consistent cooperation of all currents mediated by these channels and NCX. We suggest that the activation of Kir2.x and HCN channels by extracellular K+, that creates positive and negative feedback, and known ammonia and K+ resemblance, may provide conditions required for the activation of all the chain of channels involved in the interplay. Here, we present a mechanistic model describing an interplay of channels and second messengers, which may explain discovered antagonism of β-NAD and ammonia on rat papillary muscle contractile activity.
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Affiliation(s)
- Alexey S. Averin
- Institute of Theoretical and Experimental Biophysics, the Russian Academy of Sciences, Pushchino 142290, Russia
| | - Maxim V. Konakov
- Institute of Theoretical and Experimental Biophysics, the Russian Academy of Sciences, Pushchino 142290, Russia
| | - Oleg Y. Pimenov
- Institute of Theoretical and Experimental Biophysics, the Russian Academy of Sciences, Pushchino 142290, Russia
| | - Miliausha H. Galimova
- Institute of Theoretical and Experimental Biophysics, the Russian Academy of Sciences, Pushchino 142290, Russia
| | - Alexey V. Berezhnov
- Institute of Cell Biophysics, the Russian Academy of Sciences, Pushchino 142290, Russia
| | - Miroslav N. Nenov
- Institute of Theoretical and Experimental Biophysics, the Russian Academy of Sciences, Pushchino 142290, Russia
| | - Vladimir V. Dynnik
- Institute of Theoretical and Experimental Biophysics, the Russian Academy of Sciences, Pushchino 142290, Russia
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Xynogalos P, Rahm AK, Fried S, Chasan S, Scherer D, Seyler C, Katus HA, Frey N, Zitron E. Verapamil inhibits Kir2.3 channels by binding to the pore and interfering with PIP2 binding. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2022; 396:659-667. [PMID: 36445385 PMCID: PMC10042922 DOI: 10.1007/s00210-022-02342-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/15/2022] [Indexed: 11/30/2022]
Abstract
Abstract
The inwardly rectifying potassium current of the cardiomyocyte (IK1) is the main determinant of the resting potential. Ion channels Kir2.1, Kir2.2, and Kir2.3 form tetramers and are the molecular correlate of macroscopic IK1 current. Verapamil is an antiarrhythmic drug used to suppress atrial and ventricular arrhythmias. Its primary mechanism of action is via blocking calcium channels. In addition, it has been demonstrated to block IK1 current and the Kir2.1 subunit. Its effect on other subunits that contribute to IK1 current has not been studied to date. We therefore analyzed the effect of verapamil on the Kir channels 2.1, 2.2, and 2.3 in the Xenopus oocyte expression system. Kir2.1, Kir2.2, and Kir2.3 channels were heterologously expressed in Xenopus oocytes. Respective currents were measured with the voltage clamp technique and the effect of verapamil on the current was measured. At a concentration of 300 µM, verapamil inhibited Kir2.1 channels by 41.36% ± 2.7 of the initial current, Kir2.2 channels by 16.51 ± 3.6%, and Kir2.3 by 69.98 ± 4.2%. As a verapamil effect on kir2.3 was a previously unknown finding, we analyzed this effect further. At wash in with 300 µM verapamil, the maximal effect was seen within 20 min of the infusion. After washing out with control solution, there was only a partial current recovery. The current reduction from verapamil was the same at − 120 mV (73.2 ± 3.7%), − 40 mV (85.5 ± 6.5%), and 0 mV (61.5 ± 10.6%) implying no voltage dependency of the block. Using site directed mutations in putative binding sites, we demonstrated a decrease of effect with pore mutant E291A and absence of verapamil effect for D251A. With mutant I214L, which shows a stronger affinity for PIP2 binding, we observed a normalized current reduction to 61.9 ± 0.06% of the control current, which was significantly less pronounced compared to wild type channels. Verapamil blocks Kir2.1, Kir2.2, and Kir2.3 subunits. In Kir2.3, blockade is dependent on sites E291 and D251 and interferes with activation of the channel via PIP2. Interference with these sites and with PIP2 binding has also been described for other Kir channels blocking drugs. As Kir2.3 is preferentially expressed in atrium, a selective Kir2.3 blocking agent would constitute an interesting antiarrhythmic concept.
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Adenosine and Adenosine Receptors: Advances in Atrial Fibrillation. Biomedicines 2022; 10:biomedicines10112963. [PMID: 36428533 PMCID: PMC9687155 DOI: 10.3390/biomedicines10112963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/07/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in the world. Because the key to developing innovative therapies that limit the onset and the progression of AF is to fully understand the underlying molecular mechanisms of AF, the aim of the present narrative review is to report the most recent advances in the potential role of the adenosinergic system in the pathophysiology of AF. After a comprehensive approach describing adenosinergic system signaling and the mechanisms of the initiation and maintenance of AF, we address the interactions of the adenosinergic system's signaling with AF. Indeed, adenosine release can activate four G-coupled membrane receptors, named A1, A2A, A2B and A3. Activation of the A2A receptors can promote the occurrence of delayed depolarization, while activation of the A1 receptors can shorten the action potential's duration and induce the resting membrane's potential hyperpolarization, which promote pulmonary vein firing, stabilize the AF rotors and allow for functional reentry. Moreover, the A2B receptors have been associated with atrial fibrosis homeostasis. Finally, the adenosinergic system can modulate the autonomous nervous system and is associated with AF risk factors. A question remains regarding adenosine release and the adenosine receptors' activation and whether this would be a cause or consequence of AF.
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10
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Boyle Y, Johns TG, Fletcher EV. Potassium Ion Channels in Malignant Central Nervous System Cancers. Cancers (Basel) 2022; 14:cancers14194767. [PMID: 36230692 PMCID: PMC9563970 DOI: 10.3390/cancers14194767] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/19/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
Malignant central nervous system (CNS) cancers are among the most difficult to treat, with low rates of survival and a high likelihood of recurrence. This is primarily due to their location within the CNS, hindering adequate drug delivery and tumour access via surgery. Furthermore, CNS cancer cells are highly plastic, an adaptive property that enables them to bypass targeted treatment strategies and develop drug resistance. Potassium ion channels have long been implicated in the progression of many cancers due to their integral role in several hallmarks of the disease. Here, we will explore this relationship further, with a focus on malignant CNS cancers, including high-grade glioma (HGG). HGG is the most lethal form of primary brain tumour in adults, with the majority of patient mortality attributed to drug-resistant secondary tumours. Hence, targeting proteins that are integral to cellular plasticity could reduce tumour recurrence, improving survival. This review summarises the role of potassium ion channels in malignant CNS cancers, specifically how they contribute to proliferation, invasion, metastasis, angiogenesis, and plasticity. We will also explore how specific modulation of these proteins may provide a novel way to overcome drug resistance and improve patient outcomes.
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Affiliation(s)
- Yasmin Boyle
- Telethon Kids Institute, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, Perth, WA 6009, Australia
- School of Biomedicine, The University of Western Australia, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia
- Correspondence:
| | - Terrance G. Johns
- Telethon Kids Institute, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, Perth, WA 6009, Australia
- School of Biomedicine, The University of Western Australia, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia
| | - Emily V. Fletcher
- Telethon Kids Institute, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, Perth, WA 6009, Australia
- School of Biomedicine, The University of Western Australia, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia
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11
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Crespo-García T, Cámara-Checa A, Dago M, Rubio-Alarcón M, Rapún J, Tamargo J, Delpón E, Caballero R. Regulation of cardiac ion channels by transcription factors: Looking for new opportunities of druggable targets for the treatment of arrhythmias. Biochem Pharmacol 2022; 204:115206. [PMID: 35963339 DOI: 10.1016/j.bcp.2022.115206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 11/29/2022]
Abstract
Cardiac electrical activity is governed by different ion channels that generate action potentials. Acquired or inherited abnormalities in the expression and/or function of ion channels usually result in electrophysiological changes that can cause cardiac arrhythmias. Transcription factors (TFs) control gene transcription by binding to specific DNA sequences adjacent to target genes. Linkage analysis, candidate-gene screening within families, and genome-wide association studies have linked rare and common genetic variants in the genes encoding TFs with genetically-determined cardiac arrhythmias. Besides its critical role in cardiac development, recent data demonstrated that they control cardiac electrical activity through the direct regulation of the expression and function of cardiac ion channels in adult hearts. This narrative review summarizes some studies showing functional data on regulation of the main human atrial and ventricular Na+, Ca2+, and K+ channels by cardiac TFs such as Pitx2c, Tbx20, Tbx5, Zfhx3, among others. The results have improved our understanding of the mechanisms regulating cardiac electrical activity and may open new avenues for therapeutic interventions in cardiac acquired or inherited arrhythmias through the identification of TFs as potential drug targets. Even though TFs have for a long time been considered as 'undruggable' targets, advances in structural biology have led to the identification of unique pockets in TFs amenable to be targeted with small-molecule drugs or peptides that are emerging as novel therapeutic drugs.
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Affiliation(s)
- T Crespo-García
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - A Cámara-Checa
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - M Dago
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - M Rubio-Alarcón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - J Rapún
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - J Tamargo
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - E Delpón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain.
| | - R Caballero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
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- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
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Liu Q, Sun J, Dong Y, Li P, Wang J, Wang Y, Xu Y, Tian X, Wu B, He P, Yu Q, Lu X, Cao J. Tetramisole is a new I K1 channel agonist and exerts I K1 -dependent cardioprotective effects in rats. Pharmacol Res Perspect 2022; 10:e00992. [PMID: 35880674 PMCID: PMC9316008 DOI: 10.1002/prp2.992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 06/22/2022] [Accepted: 07/04/2022] [Indexed: 11/30/2022] Open
Abstract
Cardiac ischemia, hypoxia, arrhythmias, and heart failure share the common electrophysiological changes featured by the elevation of intracellular Ca2+ (Ca2+ overload) and inhibition of the inward rectifier potassium (IK1 ) channel. IK1 channel agonists have been considered a new type of anti-arrhythmia and cardioprotective agents. We predicted using a drug repurposing strategy that tetramisole (Tet), a known anthelminthic agent, was a new IK1 channel agonist. The present study aimed to experimentally identify the above prediction and further demonstrate that Tet has cardioprotective effects. Results of the whole-cell patch clamp technique showed that Tet at 1-100 μmol/L enhanced IK1 current, hyperpolarized resting potential (RP), and shortened action potential duration (APD) in isolated rat cardiomyocytes, while without effects on other ion channels or transporters. In adult Sprague-Dawley (SD) rats in vivo, Tet showed anti-arrhythmia and anticardiac remodeling effects, respectively, in the coronary ligation-induced myocardial infarction model and isoproterenol (Iso, i.p., 3 mg/kg/day, 10 days) infusion-induced cardiac remodeling model. Tet also showed anticardiomyocyte remodeling effect in Iso (1 μmol/L) infused adult rat ventricular myocytes or cultured H9c2 (2-1) cardiomyocytes. Tet at 0.54 mg/kg in vivo or 30 μmol/L in vitro showed promising protections on acute ischemic arrhythmias, myocardial hypertrophy, and fibrosis. Molecular docking was performed and identified the selective binding of Tet with Kir2.1. The cardioprotection of Tet was associated with the facilitation of IK1 channel forward trafficking, deactivation of PKA signaling, and inhibition of intracellular calcium overload. Enhancing IK1 may play dual roles in anti-arrhythmia and antiventricular remodeling mediated by restoration of Ca2+ homeostasis.
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Affiliation(s)
- Qinghua Liu
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Jiaxing Sun
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Yangdou Dong
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Pan Li
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Jin Wang
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
| | - Yulan Wang
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
| | - Yanwu Xu
- Department of BiochemistryShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Xinrui Tian
- Department of Respiratory and Critical Care MedicineSecond Hospital of Shanxi Medical UniversityTaiyuanChina
| | - Bowei Wu
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
| | - Peifeng He
- Shanxi Key Laboratory of Big Data for Clinical Decision Research, School of ManagementShanxi Medical UniversityTaiyuanChina
| | - Qi Yu
- Shanxi Key Laboratory of Big Data for Clinical Decision Research, School of ManagementShanxi Medical UniversityTaiyuanChina
| | - Xuechun Lu
- Department of Hematology, The Second Medical Center, Chinese PLA General HospitalNational clinical research center for geriatric diseaseBeijingChina
| | - Jimin Cao
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
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Younis A, Nehoray N, Glikson M, Bodurian C, Nof E, Bragazzi NL, Berger M, Zareba W, Goldenberg I, Beinart R. QTc Dynamics Following Cardioversion for Persistent Atrial Fibrillation. Front Cardiovasc Med 2022; 9:881446. [PMID: 35722129 PMCID: PMC9205203 DOI: 10.3389/fcvm.2022.881446] [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: 02/22/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundCardioversion (CV) for atrial fibrillation (AF) is common. We aimed to assess changes in QTc over time following electrical CV (ECV) for persistent AF, and to compare the benefit of using continuous Holter monitoring vs. conventional follow-up by ECG.MethodsProspective observational cohort study. We comprised 90 patients admitted to our center for elective ECV due to persistent AF who were prospectively enrolled from July 2017 to August 2018. All patients underwent 7-days Holter started prior to ECV. Baseline QTc was defined as median QTc during 1 h post ECV. The primary endpoint was QTc prolongation defined as QTc ≥500 ms, or ≥10% increase (if baseline QTc was >480 ms). Conventional monitoring was defined as 2-h ECG post ECV.ResultsMean age was 67 ± 11 years and 61% were male. Median baseline QTc was 452 ms (IQ range: 431–479 ms) as compared with a maximal median QTc of 474 ms (IQ range: 433–527 ms; p <0.001 for the change in QTc from baseline). Peak median QTc occurred 44 h post ECV. The primary endpoint was met in 3 patients (3%) using conventional monitoring, compared with 39 new patients (43%) using Holter (p <0.001 for comparison). The Holter monitoring was superior to conventional monitoring in detecting clinically significant QTc prolongation (OR = 13; p <0.001).ConclusionsECV of patients with persistent AF was associated with increased transient risk of QTc prolongation in nearly half of the patients. Peak median QTc occurs during end of second day following ECV and prolonged ECG monitoring provides superior detection of significant QTc prolongation compared with conventional monitoring.
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Affiliation(s)
- Arwa Younis
- Cardiac Electrophysiology and Pacing Section, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH, United States
- *Correspondence: Arwa Younis ; orcid.org/0000-0002-2485-5025
| | - Nofrat Nehoray
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
| | - Michael Glikson
- Heart Center, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Christopher Bodurian
- Clinical Cardiovascular Research Center, University of Rochester, Rochester, NY, United States
| | - Eyal Nof
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
| | - Nicola Luigi Bragazzi
- Laboratory for Industrial and Applied Mathematics, Center for Disease Modeling, York University, Toronto, ON, Canada
| | - Michael Berger
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
| | - Wojciech Zareba
- Clinical Cardiovascular Research Center, University of Rochester, Rochester, NY, United States
| | - Ilan Goldenberg
- Clinical Cardiovascular Research Center, University of Rochester, Rochester, NY, United States
| | - Roy Beinart
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
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14
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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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15
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Caveolin-3 and Arrhythmias: Insights into the Molecular Mechanisms. J Clin Med 2022; 11:jcm11061595. [PMID: 35329921 PMCID: PMC8952412 DOI: 10.3390/jcm11061595] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 02/07/2023] Open
Abstract
Caveolin-3 is a muscle-specific protein on the membrane of myocytes correlated with a variety of cardiovascular diseases. It is now clear that the caveolin-3 plays a critical role in the cardiovascular system and a significant role in cardiac protective signaling. Mutations in the gene encoding caveolin-3 cause a broad spectrum of clinical phenotypes, ranging from persistent elevations in the serum levels of creatine kinase in asymptomatic humans to cardiomyopathy. The influence of Caveolin-3(CAV-3) mutations on current density parallels the effect on channel trafficking. For example, mutations in the CAV-3 gene promote ventricular arrhythmogenesis in long QT syndrome 9 by a combined decrease in the loss of the inward rectifier current (IK1) and gain of the late sodium current (INa-L). The functional significance of the caveolin-3 has proved that caveolin-3 overexpression or knockdown contributes to the occurrence and development of arrhythmias. Caveolin-3 overexpression could lead to reduced diastolic spontaneous Ca2+ waves, thus leading to the abnormal L-Type calcium channel current-induced ventricular arrhythmias. Moreover, CAV-3 knockdown resulted in a shift to more negative values in the hyperpolarization-activated cyclic nucleotide channel 4 current (IHCN4) activation curve and a significant decrease in IHCN4 whole-cell current density. Recent evidence indicates that caveolin-3 plays a significant role in adipose tissue and is related to obesity development. The role of caveolin-3 in glucose homeostasis has attracted increasing attention. This review highlights the underlining mechanisms of caveolin-3 in arrhythmia. Progress in this field may contribute to novel therapeutic approaches for patients prone to developing arrhythmia.
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Changes in ion channel expression and function associated with cardiac arrhythmogenic remodeling by Sorbs2. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166247. [PMID: 34487812 DOI: 10.1016/j.bbadis.2021.166247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 08/03/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022]
Abstract
The Sorbin and SH3 domain-containing protein 2 (Sorbs2) is an important component of cardiomyocyte sarcomere. It has been recently reported that loss of Sorbs2 is causally associated with arrhythmogenic cardiomyopathy in human. However, the ionic mechanisms leading to cardiac arrhythmogenesis by Sorbs2 deficiency are unknown. In this study, we hypothesized that Sorbs2 plays an important role in regulating cardiac ion channel expression and function. Using electrophysiological and molecular biological approaches, we found that the Sorbs2 knockout (KO) mice progressively developed cardiac structural and electrical remodeling as early as 1 to 2 months of age and died prematurely at 5 to 7 months of age. Electrocardiographic recordings showed that Sorbs2 KO mice had conduction delays, spontaneous ventricular extrasystoles and polymorphic ventricular tachyarrhythmia. Intracellular recordings revealed abnormal action potentials with depolarized resting potential, reduced upstroke velocity, prolonged repolarization, and effective refractory period in the ventricular preparations of Sorbs2 KO mice. Patch clamp experiments demonstrated that Sorbs2 KO mice displayed distinct abnormalities in the expression and function of cardiac ion channels, including those of the voltage-gated Na+ channels, L-type Ca2+ channels, the voltage-gated K+ channels and the inward-rectifier K+ channels. Moreover, Sorbs2 physically interacted with the RNAs and/or proteins of important cardiac ion channels and directly regulated their expression in vitro. Our results indicate that Sorbs2 plays a pivotal role in the regulation of cardiac channel physiology. Loss of Sorbs2 promotes cardiac ion channelopathies and life-threatening arrhythmias.
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Lin YF. Potassium channels as molecular targets of endocannabinoids. Channels (Austin) 2021; 15:408-423. [PMID: 34282702 PMCID: PMC8293965 DOI: 10.1080/19336950.2021.1910461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 10/25/2022] Open
Abstract
Endocannabinoids are a group of endogenous mediators derived from membrane lipids, which are implicated in a wide variety of physiological functions such as blood pressure regulation, immunity, pain, memory, reward, perception, reproduction, and sleep. N-Arachidonoylethanolamine (anandamide; AEA) and 2-arachidonoylglycerol (2-AG) represent two major endocannabinoids in the human body and they exert many of their cellular and organ system effects by activating the Gi/o protein-coupled, cannabinoid type 1 (CB1) and type 2 (CB2) receptors. However, not all effects of cannabinoids are ascribable to their interaction with CB1 and CB2 receptors; indeed, macromolecules like other types of receptors, ion channels, transcription factors, enzymes, transporters, and cellular structure have been suggested to mediate the functional effects of cannabinoids. Among the proposed molecular targets of endocannabinoids, potassium channels constitute an intriguing group, because these channels not only are crucial in shaping action potentials and controlling the membrane potential and cell excitability, thereby regulating a wide array of physiological processes, but also serve as potential therapeutic targets for the treatment of cancer and metabolic, neurological and cardiovascular disorders. This review sought to survey evidence pertaining to the CB1 and CB2 receptor-independent actions of endocannabinoids on ion channels, with an emphasis on AEA and potassium channels. To better understand the functional roles as well as potential medicinal uses of cannabinoids in human health and disease, further mechanistic studies to delineate interactions between various types of cannabinoids and ion channels, including members in the potassium channel superfamily, are warranted.
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Affiliation(s)
- Yu-Fung Lin
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
- Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, CA, USA
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18
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Akyuz E, Koklu B, Uner A, Angelopoulou E, Paudel YN. Envisioning the role of inwardly rectifying potassium (Kir) channel in epilepsy. J Neurosci Res 2021; 100:413-443. [PMID: 34713909 DOI: 10.1002/jnr.24985] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/23/2021] [Accepted: 10/01/2021] [Indexed: 01/29/2023]
Abstract
Epilepsy is a devastating neurological disorder characterized by recurrent seizures attributed to the disruption of the dynamic excitatory and inhibitory balance in the brain. Epilepsy has emerged as a global health concern affecting about 70 million people worldwide. Despite recent advances in pre-clinical and clinical research, its etiopathogenesis remains obscure, and there are still no treatment strategies modifying disease progression. Although the precise molecular mechanisms underlying epileptogenesis have not been clarified yet, the role of ion channels as regulators of cellular excitability has increasingly gained attention. In this regard, emerging evidence highlights the potential implication of inwardly rectifying potassium (Kir) channels in epileptogenesis. Kir channels consist of seven different subfamilies (Kir1-Kir7), and they are highly expressed in both neuronal and glial cells in the central nervous system. These channels control the cell volume and excitability. In this review, we discuss preclinical and clinical evidence on the role of the several subfamilies of Kir channels in epileptogenesis, aiming to shed more light on the pathogenesis of this disorder and pave the way for future novel therapeutic approaches.
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Affiliation(s)
- Enes Akyuz
- Faculty of International Medicine, Department of Biophysics, University of Health Sciences, Istanbul, Turkey
| | - Betul Koklu
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Arda Uner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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19
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Crotti L, Odening KE, Sanguinetti MC. Heritable arrhythmias associated with abnormal function of cardiac potassium channels. Cardiovasc Res 2021; 116:1542-1556. [PMID: 32227190 DOI: 10.1093/cvr/cvaa068] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/24/2020] [Accepted: 03/26/2020] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes express a surprisingly large number of potassium channel types. The primary physiological functions of the currents conducted by these channels are to maintain the resting membrane potential and mediate action potential repolarization under basal conditions and in response to changes in the concentrations of intracellular sodium, calcium, and ATP/ADP. Here, we review the diversity and functional roles of cardiac potassium channels under normal conditions and how heritable mutations in the genes encoding these channels can lead to distinct arrhythmias. We briefly review atrial fibrillation and J-wave syndromes. For long and short QT syndromes, we describe their genetic basis, clinical manifestation, risk stratification, traditional and novel therapeutic approaches, as well as insights into disease mechanisms provided by animal and cellular models.
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Affiliation(s)
- Lia Crotti
- Center for Cardiac Arrhythmias of Genetic Origin, Istituto Auxologico Italiano, IRCCS, Milan, Italy.,Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan, Italy.,Department of Cardiovascular, Neural and Metabolic Sciences, Istituto Auxologico Italiano, IRCCS, San Luca Hospital, Milan, Italy.,Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Katja E Odening
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Institute of Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Department of Cardiology, Translational Cardiology, Inselspital, Bern University Hospital, and Institute of Physiology, University of Bern, Bern, Switzerland
| | - Michael C Sanguinetti
- Department of Internal Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA
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20
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Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications. Handb Exp Pharmacol 2021; 267:277-356. [PMID: 34345939 DOI: 10.1007/164_2021_501] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K+ channels. In the present review we focus on placing the physiology and pharmacology of this K+ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.
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21
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Auzmendi J, Akyuz E, Lazarowski A. The role of P-glycoprotein (P-gp) and inwardly rectifying potassium (Kir) channels in sudden unexpected death in epilepsy (SUDEP). Epilepsy Behav 2021; 121:106590. [PMID: 31706919 DOI: 10.1016/j.yebeh.2019.106590] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/17/2019] [Accepted: 09/23/2019] [Indexed: 12/13/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the major cause of death that affects patients with epilepsy. The risk of SUDEP increases according to the frequency and severity of uncontrolled seizures; therefore, SUDEP risk is higher in patients with refractory epilepsy (RE), in whom most antiepileptic drugs (AEDs) are ineffective for both seizure control and SUDEP prevention. Consequently, RE and SUDEP share a multidrug resistance (MDR) phenotype, which is mainly associated with brain overexpression of ABC-transporters such as P-glycoprotein (P-gp). The activity of P-gp can also contribute to membrane depolarization and affect the normal function of neurons and cardiomyocytes. Other molecular regulators of membrane potential are the inwardly rectifying potassium channels (Kir), whose genetic variants have been related to both epilepsy and heart dysfunctions. Although it has been suggested that dysfunctions of the cardiac, respiratory, and brainstem arousal systems are the causes of SUDEP, the molecular basis for explaining its dysfunctions remain unknown. In rats, repetitive seizures or status epilepticus induced high expression of P-gp and loss Kir expression in the brain and heart, and promoted membrane depolarization, malignant bradycardia, and the high rate of mortality. Here we reviewed clinical and experimental evidences suggesting that abnormal expression of depolarizing/repolarizing factors as P-gp and Kir could favor persistent depolarization of membranes without any rapid functional recovery capacity. This condition induced by convulsive stress could be the molecular mechanism leading to acquired severe bradycardia, as an ineffective heart response generating the appropriate scenario for SUDEP development. This article is part of the Special Issue "NEWroscience 2018".
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Affiliation(s)
- Jerónimo Auzmendi
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina; INFIBIOC, Departamento de Bioquímica Clínica, Facultad de Farmacia y Bioquímica (FFyB), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Enes Akyuz
- Yozgat Bozok University, Medical Faculty, Department of Biophysics, Erdoğan Akdağ Yerleşkesi, 66100 Yozgat, Turkey
| | - Alberto Lazarowski
- INFIBIOC, Departamento de Bioquímica Clínica, Facultad de Farmacia y Bioquímica (FFyB), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.
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Déri S, Borbás J, Hartai T, Hategan L, Csányi B, Visnyovszki Á, Madácsy T, Maléth J, Hegedűs Z, Nagy I, Arora R, Labro AJ, Környei L, Varró A, Sepp R, Ördög B. Impaired cytoplasmic domain interactions cause co-assembly defect and loss of function in the p.Glu293Lys KNCJ2 variant isolated from an Andersen-Tawil syndrome patient. Cardiovasc Res 2021; 117:1923-1934. [PMID: 32810216 DOI: 10.1093/cvr/cvaa249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/16/2020] [Accepted: 08/12/2020] [Indexed: 02/07/2023] Open
Abstract
AIMS Subunit interactions at the cytoplasmic domain interface (CD-I) have recently been shown to control gating in inward rectifier potassium channels. Here we report the novel KCNJ2 variant p.Glu293Lys that has been found in a patient with Andersen-Tawil syndrome type 1 (ATS1), causing amino acid substitution at the CD-I of the inward rectifier potassium channel subunit Kir2.1. Neither has the role of Glu293 in gating control been investigated nor has a pathogenic variant been described at this position. This study aimed to assess the involvement of Glu293 in CD-I subunit interactions and to establish the pathogenic role of the p.Glu293Lys variant in ATS1. METHODS AND RESULTS The p.Glu293Lys variant produced no current in homomeric form and showed dominant-negative effect over wild-type (WT) subunits. Immunocytochemical labelling showed the p.Glu293Lys subunits to distribute in the subsarcolemmal space. Salt bridge prediction indicated the presence of an intersubunit salt bridge network at the CD-I of Kir2.1, with the involvement of Glu293. Subunit interactions were studied by the NanoLuc® Binary Technology (NanoBiT) split reporter assay. Reporter constructs carrying NanoBiT tags on the intracellular termini produced no bioluminescent signal above background with the p.Glu293Lys variant in homomeric configuration and significantly reduced signals in cells co-expressing WT and p.Glu293Lys subunits simultaneously. Extracellularly presented reporter tags, however, generated comparable bioluminescent signals with heteromeric WT and p.Glu293Lys subunits and with homomeric WT channels. CONCLUSIONS Loss of function and dominant-negative effect confirm the causative role of p.Glu293Lys in ATS1. Co-assembly of Kir2.1 subunits is impaired in homomeric channels consisting of p.Glu293Lys subunits and is partially rescued in heteromeric complexes of WT and p.Glu293Lys Kir2.1 variants. These data point to an important role of Glu293 in mediating subunit assembly, as well as in gating of Kir2.1 channels.
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Affiliation(s)
- Szilvia Déri
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 12, 6720 Szeged, Hungary
| | - János Borbás
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Teodóra Hartai
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
| | - Lidia Hategan
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Beáta Csányi
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Ádám Visnyovszki
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
| | - Tamara Madácsy
- 1st Department of Internal Medicine, University of Szeged, Korányi fasor 8-10, 6720 Szeged, Hungary, Hungary
| | - József Maléth
- 1st Department of Internal Medicine, University of Szeged, Korányi fasor 8-10, 6720 Szeged, Hungary, Hungary
| | - Zoltán Hegedűs
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary
- Department of Biochemistry and Medical Chemistry, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - István Nagy
- Institute of Biochemistry, Biological Research Centre the Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary
- Seqomics Biotechnology Ltd, Vállalkozók útja 7, 6782 Mórahalom, Hungary
| | - Rohit Arora
- Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
| | - Alain J Labro
- Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
- Department of Basic Medical Sciences, University of Ghent, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - László Környei
- Gottsegen György National Institute of Cardiology, Haller u. 9, 1096 Budapest, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 12, 6720 Szeged, Hungary
- MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Dóm tér 12, 6720 Szeged, Hungary
| | - Róbert Sepp
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Balázs Ördög
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
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Tissone AI, Vidal VB, Nadal MS, Mato G, Amarillo Y. Differential contribution of the subthreshold operating currents IT, Ih, and IKir to the resonance of thalamocortical neurons. J Neurophysiol 2021; 126:561-574. [PMID: 34232785 DOI: 10.1152/jn.00147.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Membrane potential oscillations of thalamocortical (TC) neurons are believed to be involved in the generation and maintenance of brain rhythms that underlie global physiological and pathological brain states. These membrane potential oscillations depend on the synaptic interactions of TC neurons and their intrinsic electrical properties. These oscillations may be also shaped by increased output responses at a preferred frequency, known as intrinsic neuronal resonance. Here, we combine electrophysiological recordings in mouse brain slices, modern pharmacological tools, dynamic clamp, and computational modeling to study the ionic mechanisms that generate and modulate TC neuron resonance. We confirm findings of pioneering studies showing that most TC neurons display resonance that results from the interaction of the slow inactivation of the low-threshold calcium current IT with the passive properties of the membrane. We also show that the hyperpolarization-activated cationic current Ih is not involved in the generation of resonance; instead it plays a minor role in the stabilization of TC neuron impedance magnitude due to its large contribution to the steady conductance. More importantly, we also demonstrate that TC neuron resonance is amplified by the inward rectifier potassium current IKir by a mechanism that hinges on its strong voltage-dependent inward rectification (i.e., a negative slope conductance region). Accumulating evidence indicate that the ion channels that control the oscillatory behavior of TC neurons participate in pathophysiological processes. Results presented here points to IKir as a new potential target for therapeutic intervention.NEW & NOTEWORTHY Our study expands the repertoire of ionic mechanisms known to be involved in the generation and control of resonance and provides the first experimental proof of previous theoretical predictions on resonance amplification mediated by regenerative hyperpolarizing currents. In thalamocortical neurons, we confirmed that the calcium current IT generates resonance, determined that the large steady conductance of the cationic current Ih curtails resonance, and demonstrated that the inward rectifier potassium current IKir amplifies resonance.
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Affiliation(s)
- Angela Isabel Tissone
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Consejo Nacional de Investigaciones Científicas y Técnicas, San Carlos de Bariloche, Río Negro, Argentina.,Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, San Carlos de Bariloche, Río Negro, Argentina
| | - Varinia Beatriz Vidal
- Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, San Carlos de Bariloche, Río Negro, Argentina
| | - Marcela Silvia Nadal
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Consejo Nacional de Investigaciones Científicas y Técnicas, San Carlos de Bariloche, Río Negro, Argentina.,Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, San Carlos de Bariloche, Río Negro, Argentina
| | - German Mato
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo (UNCUYO), San Carlos de Bariloche, Río Negro, Argentina
| | - Yimy Amarillo
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Consejo Nacional de Investigaciones Científicas y Técnicas, San Carlos de Bariloche, Río Negro, Argentina
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24
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Clerx M, Mirams GR, Rogers AJ, Narayan SM, Giles WR. Immediate and Delayed Response of Simulated Human Atrial Myocytes to Clinically-Relevant Hypokalemia. Front Physiol 2021; 12:651162. [PMID: 34122128 PMCID: PMC8188899 DOI: 10.3389/fphys.2021.651162] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/22/2021] [Indexed: 12/18/2022] Open
Abstract
Although plasma electrolyte levels are quickly and precisely regulated in the mammalian cardiovascular system, even small transient changes in K+, Na+, Ca2+, and/or Mg2+ can significantly alter physiological responses in the heart, blood vessels, and intrinsic (intracardiac) autonomic nervous system. We have used mathematical models of the human atrial action potential (AP) to explore the electrophysiological mechanisms that underlie changes in resting potential (Vr) and the AP following decreases in plasma K+, [K+]o, that were selected to mimic clinical hypokalemia. Such changes may be associated with arrhythmias and are commonly encountered in patients (i) in therapy for hypertension and heart failure; (ii) undergoing renal dialysis; (iii) with any disease with acid-base imbalance; or (iv) post-operatively. Our study emphasizes clinically-relevant hypokalemic conditions, corresponding to [K+]o reductions of approximately 1.5 mM from the normal value of 4 to 4.5 mM. We show how the resulting electrophysiological responses in human atrial myocytes progress within two distinct time frames: (i) Immediately after [K+]o is reduced, the K+-sensing mechanism of the background inward rectifier current (IK1) responds. Specifically, its highly non-linear current-voltage relationship changes significantly as judged by the voltage dependence of its region of outward current. This rapidly alters, and sometimes even depolarizes, Vr and can also markedly prolong the final repolarization phase of the AP, thus modulating excitability and refractoriness. (ii) A second much slower electrophysiological response (developing 5-10 minutes after [K+]o is reduced) results from alterations in the intracellular electrolyte balance. A progressive shift in intracellular [Na+]i causes a change in the outward electrogenic current generated by the Na+/K+ pump, thereby modifying Vr and AP repolarization and changing the human atrial electrophysiological substrate. In this study, these two effects were investigated quantitatively, using seven published models of the human atrial AP. This highlighted the important role of IK1 rectification when analyzing both the mechanisms by which [K+]o regulates Vr and how the AP waveform may contribute to "trigger" mechanisms within the proarrhythmic substrate. Our simulations complement and extend previous studies aimed at understanding key factors by which decreases in [K+]o can produce effects that are known to promote atrial arrhythmias in human hearts.
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Affiliation(s)
- Michael Clerx
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Gary R Mirams
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Albert J Rogers
- Department of Medicine and Cardiovascular Institute, Stanford University, Stanford, CA, United States
| | - Sanjiv M Narayan
- Department of Medicine and Cardiovascular Institute, Stanford University, Stanford, CA, United States
| | - Wayne R Giles
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
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25
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Yang D, Wan X, Dennis AT, Bektik E, Wang Z, Costa MG, Fagnen C, Vénien-Bryan C, Xu X, Gratz DH, Hund TJ, Mohler PJ, Laurita KR, Deschênes I, Fu JD. MicroRNA Biophysically Modulates Cardiac Action Potential by Direct Binding to Ion Channel. Circulation 2021; 143:1597-1613. [PMID: 33590773 PMCID: PMC8132313 DOI: 10.1161/circulationaha.120.050098] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND MicroRNAs (miRs) play critical roles in regulation of numerous biological events, including cardiac electrophysiology and arrhythmia, through a canonical RNA interference mechanism. It remains unknown whether endogenous miRs modulate physiologic homeostasis of the heart through noncanonical mechanisms. METHODS We focused on the predominant miR of the heart (miR1) and investigated whether miR1 could physically bind with ion channels in cardiomyocytes by electrophoretic mobility shift assay, in situ proximity ligation assay, RNA pull down, and RNA immunoprecipitation assays. The functional modulations of cellular electrophysiology were evaluated by inside-out and whole-cell patch clamp. Mutagenesis of miR1 and the ion channel was used to understand the underlying mechanism. The effect on the heart ex vivo was demonstrated through investigating arrhythmia-associated human single nucleotide polymorphisms with miR1-deficient mice. RESULTS We found that endogenous miR1 could physically bind with cardiac membrane proteins, including an inward-rectifier potassium channel Kir2.1. The miR1-Kir2.1 physical interaction was observed in mouse, guinea pig, canine, and human cardiomyocytes. miR1 quickly and significantly suppressed IK1 at sub-pmol/L concentration, which is close to endogenous miR expression level. Acute presence of miR1 depolarized resting membrane potential and prolonged final repolarization of the action potential in cardiomyocytes. We identified 3 miR1-binding residues on the C-terminus of Kir2.1. Mechanistically, miR1 binds to the pore-facing G-loop of Kir2.1 through the core sequence AAGAAG, which is outside its RNA interference seed region. This biophysical modulation is involved in the dysregulation of gain-of-function Kir2.1-M301K mutation in short QT or atrial fibrillation. We found that an arrhythmia-associated human single nucleotide polymorphism of miR1 (hSNP14A/G) specifically disrupts the biophysical modulation while retaining the RNA interference function. It is remarkable that miR1 but not hSNP14A/G relieved the hyperpolarized resting membrane potential in miR1-deficient cardiomyocytes, improved the conduction velocity, and eliminated the high inducibility of arrhythmia in miR1-deficient hearts ex vivo. CONCLUSIONS Our study reveals a novel evolutionarily conserved biophysical action of endogenous miRs in modulating cardiac electrophysiology. Our discovery of miRs' biophysical modulation provides a more comprehensive understanding of ion channel dysregulation and may provide new insights into the pathogenesis of cardiac arrhythmias.
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Affiliation(s)
- Dandan Yang
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Xiaoping Wan
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Adrienne T. Dennis
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
| | - Emre Bektik
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
| | - Zhihua Wang
- Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, Shenzhen, China
| | - Mauricio G.S. Costa
- Institute of Mineralogy, Materials Physics and Cosmochemistry, UMR 7590, Sorbonne Université, CNRS, MNHN, Paris F-75005, France
- Oswaldo Cruz Foundation, Scientific Computing Program, Vice Presidency of Education, Information and Communication, Rio de Janeiro, Brazil
| | - Charline Fagnen
- Institute of Mineralogy, Materials Physics and Cosmochemistry, UMR 7590, Sorbonne Université, CNRS, MNHN, Paris F-75005, France
| | - Catherine Vénien-Bryan
- Institute of Mineralogy, Materials Physics and Cosmochemistry, UMR 7590, Sorbonne Université, CNRS, MNHN, Paris F-75005, France
| | - Xianyao Xu
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Departments of Biomedical Engineering and Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel H. Gratz
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Departments of Biomedical Engineering and Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Thomas J. Hund
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Departments of Biomedical Engineering and Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Peter J. Mohler
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Kenneth R. Laurita
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
| | - Isabelle Deschênes
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ji-Dong Fu
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
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Reilly L, Eckhardt LL. Cardiac potassium inward rectifier Kir2: Review of structure, regulation, pharmacology, and arrhythmogenesis. Heart Rhythm 2021; 18:1423-1434. [PMID: 33857643 PMCID: PMC8328935 DOI: 10.1016/j.hrthm.2021.04.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/23/2021] [Accepted: 04/06/2021] [Indexed: 12/17/2022]
Abstract
Potassium inward rectifier channel Kir2 is an important component of terminal cardiac repolarization and resting membrane stability. This functionality is part of balanced cardiac excitability and is a defining feature of excitable cardiac membranes. “Gain-of-function” or “loss-of-function” mutations in KCNJ2, the gene encoding Kir2.1, cause genetic sudden cardiac death syndromes, and loss of the Kir2 current IK1 is a major contributing factor to arrhythmogenesis in failing human hearts. Here we provide a contemporary review of the functional structure, physiology, and pharmacology of Kir2 channels. Beyond the structure and functional relationships, we will focus on the elements of clinically used drugs that block the channel and the implications for treatment of atrial fibrillation with IK1-blocking agents. We will also review the clinical disease entities associated with KCNJ2 mutations and the growing area of research into associated arrhythmia mechanisms. Lastly, the presence of Kir2 channels has become a tipping point for electrical maturity in induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) and highlights the significance of understanding why Kir2 in iPS-CMs is important to consider for Comprehensive In Vitro Proarrhythmia Assay and drug safety testing.
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Affiliation(s)
- Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
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27
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Targeting of Potassium Channels in Cardiac Arrhythmias. Trends Pharmacol Sci 2021; 42:491-506. [PMID: 33858691 DOI: 10.1016/j.tips.2021.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 02/07/2023]
Abstract
Cardiomyocytes are endowed with a complex repertoire of ion channels, responsible for the generation of action potentials (APs), travelling waves of electrical excitation, propagating throughout the heart and leading to cardiac contractions. Cardiac AP waveforms are shaped by a striking diversity of K+ channels. The pivotal role of K+ channels in cardiac health and disease is underscored by the dramatic impact that K+ channel dysfunction has on cardiac arrhythmias. The development of drugs targeted to specific K+ channels is expected to provide an optimized approach to antiarrhythmic therapy. Here, we review the functional roles of cardiac potassium channels under normal and diseased states. We survey current antiarrhythmic drugs (AADs) targeted to voltage-gated and Ca2+-activated K+ channels and highlight future research opportunities.
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28
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Sobota V, Gatta G, van Hunnik A, van Tuijn I, Kuiper M, Milnes J, Jespersen T, Schotten U, Verheule S. The Acetylcholine-Activated Potassium Current Inhibitor XAF-1407 Terminates Persistent Atrial Fibrillation in Goats. Front Pharmacol 2021; 11:608410. [PMID: 33584287 PMCID: PMC7873360 DOI: 10.3389/fphar.2020.608410] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 12/10/2020] [Indexed: 12/20/2022] Open
Abstract
Aims: The acetylcholine-activated inward rectifier potassium current (IKACh) has been proposed as an atrial-selective target for the treatment of atrial fibrillation (AF). Using a novel selective IKACh inhibitor XAF-1407, the study investigates the effect of IKACh inhibition in goats with pacing-induced, short-term AF. Methods: Ten goats (57 ± 5 kg) were instrumented with pericardial electrodes. Electrophysiological parameters were assessed at baseline and during intravenous infusion of XAF-1407 (0.3, 3.0 mg/kg) in conscious animals before and after 2 days of electrically induced AF. Following a further 2 weeks of sustained AF, cardioversion was attempted with either XAF-1407 (0.3 followed by 3 mg/kg) or with vernakalant (3.7 followed by 4.5 mg/kg), an antiarrhythmic drug that inhibits the fast sodium current and several potassium currents. During a final open chest experiment, 249 unipolar electrograms were recorded on each atrium to construct activation patterns and AF cardioversion was attempted with XAF-1407. Results: XAF-1407 prolonged atrial effective refractory period by 36 ms (45%) and 71 ms (87%) (0.3 and 3.0 mg/kg, respectively; pacing cycle length 400 ms, 2 days of AF-induced remodeling) and showed higher cardioversion efficacy than vernakalant (8/9 vs. 5/9). XAF-1407 caused a minor decrease in the number of waves per AF cycle in the last seconds prior to cardioversion. Administration of XAF-1407 was associated with a modest increase in QTc (<10%). No ventricular proarrhythmic events were observed. Conclusion: XAF-1407 showed an antiarrhythmic effect in a goat model of AF. The study indicates that IKACh represents an interesting therapeutic target for treatment of AF. To assess the efficacy of XAF-1407 in later time points of AF-induced remodeling, follow-up studies with longer period of AF maintenance would be necessary.
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Affiliation(s)
- Vladimír Sobota
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | - Giulia Gatta
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | - Arne van Hunnik
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | - Iris van Tuijn
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | - Marion Kuiper
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | | | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ulrich Schotten
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | - Sander Verheule
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
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29
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Small G-protein RhoA is a potential inhibitor of cardiac fast sodium current. J Physiol Biochem 2020; 77:13-23. [PMID: 33145656 DOI: 10.1007/s13105-020-00774-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/27/2020] [Indexed: 12/30/2022]
Abstract
Small G-proteins of Rho family modulate the activity of several classes of ion channels, including K+ channels Kv1.2, Kir2.1, and ERG; Ca2+ channels; and epithelial Na+ channels. The present study was aimed to check the RhoA potential regulatory effects on Na+ current (INa) transferred by Na+ channel cardiac isoform NaV1.5 in heterologous expression system and in native rat cardiomyocytes. Whole-cell patch-clamp experiments showed that coexpression of NaV1.5 with the wild-type RhoA in CHO-K1 cell line caused 2.7-fold decrease of INa density with minimal influence on steady-state activation and inactivation. This effect was reproduced by the coexpression with a constitutively active RhoA, but not with a dominant negative RhoA. In isolated ventricular rat cardiomyocytes, a 5-h incubation with the RhoA activator narciclasine (5 × 10-6 M) reduced the maximal INa density by 38.8%. The RhoA-selective inhibitor rhosin (10-5 M) increased the maximal INa density by 25.3%. Experiments with sharp microelectrode recordings in isolated right ventricular wall preparations showed that 5 × 10-6 M narciclasine induced a significant reduction of action potential upstroke velocity after 2 h of incubation. Thus, RhoA might be considered as a potential negative regulator of sodium channels cardiac isoform NaV1.5.
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Liu YQ, Xue SM, Zhang P, Xu LN, Wang DP, Li G, Cao JM. Silica Nanoparticles Disturb Ion Channels and Transmembrane Potentials of Cardiomyocytes and Induce Lethal Arrhythmias in Mice. Int J Nanomedicine 2020; 15:7397-7413. [PMID: 33116478 PMCID: PMC7547143 DOI: 10.2147/ijn.s261692] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/08/2020] [Indexed: 12/22/2022] Open
Abstract
Background The toxicity of silica nanoparticles (SiNPs) on cardiac electrophysiology has seldom been evaluated. Methods Patch-clamp was used to investigate the acute effects of SiNP-100 (100 nm) and SiNP-20 (20 nm) on the transmembrane potentials (TMPs) and ion channels in cultured neonatal mouse ventricular myocytes. Calcium mobilization in vitro, cardiomyocyte ROS generation, and LDH leakage after exposure to SiNPs in vitro and in vivo were measured using a microplate reader. Surface electrocardiograms were recorded in adult mice to evaluate the arrhythmogenic effects of SiNPs in vivo. SiNP endocytosis was observed using transmission electron microscopy. Results Within 30 min, both SiNPs (10-8-10-6 g/mL) did not affect the resting potential and IK1 channels. SiNP-100 increased the action potential amplitude (APA) and the INa current density, but SiNP-20 decreased APA and INa density. SiNP-100 prolonged the action potential duration (APD) and decreased the Ito current density, while SiNP-20 prolonged or shortened the APD, depending on exposure concentrations and increased Ito density. Both SiNPs (10-6 g/mL) induced calcium mobilization but did not increase ROS and LDH levels and were not endocytosed within 10 min in cardiomyocytes in vitro. In vivo, SiNP-100 (4-10 mg/kg) and SiNP-20 (4-30 mg/kg) did not elevate myocardial ROS but increased LDH levels depending on dose and exposure time. The same higher dose of SiNPs (intravenously injected) induced tachyarrhythmias and lethal bradyarrhythmias within 90 min in adult mice. Conclusion SiNPs (i) exert rapid toxic effects on the TMPs of cardiomyocytes in vitro largely owing to their direct interfering effects on the INa and Ito channels and Ca2+ homeostasis but not IK1 channels and ROS levels, and (ii) induce tachyarrhythmias and lethal bradyarrhythmias in vivo. SiNP-100 is more toxic than SiNP-20 on cardiac electrophysiology, and the toxicity mechanism is likely more complicated in vivo.
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Affiliation(s)
- Ya-Qin Liu
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Si-Meng Xue
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Peng Zhang
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Lin-Na Xu
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - De-Ping Wang
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi 030001, People's Republic of China
| | - Guang Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Ji-Min Cao
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China.,Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi 030001, People's Republic of China
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Palacios-Martinez J, Caballero-Perez J, Espinal-Centeno A, Marquez-Chavoya G, Lomeli H, Salas-Vidal E, Schnabel D, Chimal-Monroy J, Cruz-Ramirez A. Multi-organ transcriptomic landscape of Ambystoma velasci metamorphosis. Dev Biol 2020; 466:22-35. [PMID: 32828730 DOI: 10.1016/j.ydbio.2020.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/11/2020] [Accepted: 08/04/2020] [Indexed: 12/21/2022]
Abstract
Metamorphosis is a postembryonic developmental process that involves morphophysiological and behavioral changes, allowing organisms to adapt into a novel environment. In some amphibians, aquatic organisms undergo metamorphosis to adapt in a terrestrial environment. In this process, these organisms experience major changes in their circulatory, respiratory, digestive, excretory and reproductive systems. We performed a transcriptional global analysis of heart, lung and gills during diverse stages of Ambystoma velasci to investigate its metamorphosis. In our analyses, we identified eight gene clusters for each organ, according to the expression patterns of differentially expressed genes. We found 4064 differentially expressed genes in the heart, 4107 in the lung and 8265 in the gills. Among the differentially expressed genes in the heart, we observed genes involved in the differentiation of cardiomyocytes in the interatrial zone, vasculogenesis and in the maturation of coronary vessels. In the lung, we found genes differentially expressed related to angiogenesis, alveolarization and synthesis of the surfactant protein. In the case of the gills, the most prominent biological processes identified are degradation of extracellular matrix, apoptosis and keratin production. Our study sheds light on the transcriptional responses and the pathways modulation involved in the transformation of the facultative metamorphic salamander A. velasci in an organ-specific manner.
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Affiliation(s)
- Janet Palacios-Martinez
- Molecular & Developmental Complexity Group, Unit of Advanced Genomics, UGA-CINVESTAV, Irapuato, Mexico
| | - Juan Caballero-Perez
- Molecular & Developmental Complexity Group, Unit of Advanced Genomics, UGA-CINVESTAV, Irapuato, Mexico; Department of Biochemistry, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Annie Espinal-Centeno
- Molecular & Developmental Complexity Group, Unit of Advanced Genomics, UGA-CINVESTAV, Irapuato, Mexico
| | - Gilberto Marquez-Chavoya
- Molecular & Developmental Complexity Group, Unit of Advanced Genomics, UGA-CINVESTAV, Irapuato, Mexico
| | - Hilda Lomeli
- Departamento de Genética del Desarrollo y FisioloMéxico Citygía Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor, 62250, Mexico
| | - Enrique Salas-Vidal
- Departamento de Genética del Desarrollo y FisioloMéxico Citygía Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor, 62250, Mexico
| | - Denhi Schnabel
- Departamento de Genética del Desarrollo y FisioloMéxico Citygía Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor, 62250, Mexico
| | - Jesus Chimal-Monroy
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, DF, 04510, Mexico
| | - Alfredo Cruz-Ramirez
- Molecular & Developmental Complexity Group, Unit of Advanced Genomics, UGA-CINVESTAV, Irapuato, Mexico.
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Towards the Development of AgoKirs: New Pharmacological Activators to Study K ir2.x Channel and Target Cardiac Disease. Int J Mol Sci 2020; 21:ijms21165746. [PMID: 32796537 PMCID: PMC7461056 DOI: 10.3390/ijms21165746] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/15/2022] Open
Abstract
Inward rectifier potassium ion channels (IK1-channels) of the Kir2.x family are responsible for maintaining a stable negative resting membrane potential in excitable cells, but also play a role in processes of non-excitable tissues, such as bone development. IK1-channel loss-of-function, either congenital or acquired, has been associated with cardiac disease. Currently, basic research and specific treatment are hindered by the absence of specific and efficient Kir2.x channel activators. However, twelve different compounds, including approved drugs, show off-target IK1 activation. Therefore, these compounds contain valuable information towards the development of agonists of Kir channels, AgoKirs. We reviewed the mechanism of IK1 channel activation of these compounds, which can be classified as direct or indirect activators. Subsequently, we examined the most viable starting points for rationalized drug development and possible safety concerns with emphasis on cardiac and skeletal muscle adverse effects of AgoKirs. Finally, the potential value of AgoKirs is discussed in view of the current clinical applications of potentiators and activators in cystic fibrosis therapy.
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Frost Nylén J, Carannante I, Grillner S, Hellgren Kotaleski J. Reciprocal interaction between striatal cholinergic and low‐threshold spiking interneurons — A computational study. Eur J Neurosci 2020; 53:2135-2148. [DOI: 10.1111/ejn.14854] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/28/2020] [Accepted: 05/30/2020] [Indexed: 01/04/2023]
Affiliation(s)
| | - Ilaria Carannante
- Department of Computational Science and Technology Science for Life Laboratory The Royal Institute of Technology Stockholm Sweden
| | - Sten Grillner
- Department of Neuroscience Karolinska Institutet Stockholm Sweden
| | - Jeanette Hellgren Kotaleski
- Department of Neuroscience Karolinska Institutet Stockholm Sweden
- Department of Computational Science and Technology Science for Life Laboratory The Royal Institute of Technology Stockholm Sweden
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Akyuz E, Villa C. A novel role of cardiac inwardly rectifying potassium channels explaining autonomic cardiovascular dysfunctions in a cuprizone-induced mouse model of multiple sclerosis. Auton Neurosci 2020; 225:102647. [PMID: 32087534 DOI: 10.1016/j.autneu.2020.102647] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/16/2020] [Accepted: 02/12/2020] [Indexed: 12/16/2022]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system (CNS), believed to have an autoimmune etiology. MS patients showed an increased cardiovascular (CV) risk probably related to an impairment in the autonomic control of CV functions, but the underlying molecular mechanisms are not completely elucidated. Inwardly-rectifying potassium (Kir) channels play a key role in cardiac excitability by contributing to the repolarization phase of action potential and were recently identified as target of the autoantibody response in MS patients. Therefore, we investigated the role of cardiac Kir channels in the CV dysfunctions occurring in MS. Cardiac functions were evaluated by electrocardiographic recordings (ECG) in cuprizone-fed C57BL/6 mice, a classic demyelination animal model. Gene expression profiling of cardiac Kir2.2, Kir4.1 and Kir6.2 channels was performed using real-time PCR in mice. Cuprizone-induced mouse model was confirmed by immunohistochemistry analysis showing demyelination in the corpus callosum. ECG recordings from mice showed a significant decreased duration of the P wave and RR interval as well as an increase of the heart rate in cuprizone-treated mice as compared with the controls. Significant increased relative expression levels of Kcnj11 and Kcnj12, encoding for Kir6.2 and Kir2.2 channels respectively, were observed in mouse heart tissue, whereas no differences were found in mRNA levels of Kir4.1 channel as compared with controls. For the first time, these findings provided valuable insights into the potential role of Kir channels in cardiac problems associated with MS.
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Affiliation(s)
- Enes Akyuz
- Department of Biophysics, Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey.
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, Italy
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Imoto K, Aratani M, Koyama T, Okada M, Yamawaki H. Thrombospondin-4 induces prolongation of action potential duration in rat isolated ventricular myocytes. J Vet Med Sci 2020; 82:707-712. [PMID: 32249254 PMCID: PMC7324826 DOI: 10.1292/jvms.20-0038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Expression of thrombospondin-4 (TSP-4), a matricellular protein, is increased in the
heart tissue of various cardiac disease models. In dorsal root ganglion neurons, TSP-4
inhibits L-type Ca2+ channel (LTCC) activity. Although TSP-4 might be related
to the electrophysiological properties in heart, it remains to be clarified. The present
study aimed to clarify the effects of TSP-4 on action potential (AP), LTCC current
(ICaL) and voltage-dependent K+ (Kv) channel
current (IKv) in rat isolated ventricular myocytes by a patch
clamp technique. Ventricular myocytes were isolated from the heart of adult male Wistar
rats. The ventricular myocytes were treated with TSP-4 (5 nM) or its vehicle for 4 hr.
Then, whole-cell patch clamp technique was performed to measure AP (current-clamp mode)
and ICaL and IKv (voltage-clamp
mode). The mRNA expression of Kv channels was examined by reverse transcription-polymerase
chain reaction. TSP-4 had no effect on the resting membrane potential and peak amplitude
of AP. On the other hand, TSP-4 significantly prolonged AP duration (APD) at 50% and 90%
repolarization. TSP-4 significantly inhibited the peak amplitudes of
ICaL and IKv. TSP-4 had no
effect on mRNA expression of Kv channels (Kcna4, Kcna5,
Kcnb1, Kcnd2 and Kcnd3). The present
study for the first time demonstrated that TSP-4 prolongs APD in rat ventricular myocytes,
which is possibly mediated through the suppression of Kv channel activity.
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Affiliation(s)
- Keisuke Imoto
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 bancho 35-1, Towada-shi, Aomori 034-8628, Japan
| | - Momoko Aratani
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 bancho 35-1, Towada-shi, Aomori 034-8628, Japan
| | - Takahiro Koyama
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 bancho 35-1, Towada-shi, Aomori 034-8628, Japan
| | - Muneyoshi Okada
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 bancho 35-1, Towada-shi, Aomori 034-8628, Japan
| | - Hideyuki Yamawaki
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 bancho 35-1, Towada-shi, Aomori 034-8628, Japan
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Abstract
PURPOSE OF REVIEW The goal of this paper is to review present knowledge regarding biological pacemakers created by somatic reprogramming as a platform for mechanistic and metabolic understanding of the rare subpopulation of pacemaker cells, with the ultimate goal of creating biological alternatives to electronic pacing devices. RECENT FINDINGS Somatic reprogramming of cardiomyocytes by reexpression of embryonic transcription factor T-box 18 (TBX18) converts them into pacemaker-like. Recent studies take advantage of this model to gain insight into the electromechanical, metabolic, and architectural intricacies of the cardiac pacemaker cell across various models, including a surgical model of complete atrioventricular block (CAVB) in adult rats. The studies reviewed here reinforce the potential utility of TBX18-induced pacemaker myocytes (iPMS) as a minimally invasive treatment for heart block. Several challenges which must be overcome to develop a viable therapeutic intervention based on these observations are discussed.
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Akyuz E, Villa C, Beker M, Elibol B. Unraveling the Role of Inwardly Rectifying Potassium Channels in the Hippocampus of an Aβ (1-42)-Infused Rat Model of Alzheimer's Disease. Biomedicines 2020; 8:biomedicines8030058. [PMID: 32183098 PMCID: PMC7148495 DOI: 10.3390/biomedicines8030058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/10/2020] [Accepted: 03/12/2020] [Indexed: 11/24/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with a complex etiology and characterized by cognitive deficits and memory loss. The pathogenesis of AD is not yet completely elucidated, and no curative treatment is currently available. Inwardly rectifying potassium (Kir) channels are important for playing a key role in maintaining the resting membrane potential and controlling cell excitability, being largely expressed in both excitable and non-excitable tissues, including neurons. Accordingly, the aim of the study is to investigate the role of neuronal Kir channels in AD pathophysiology. The mRNA and protein levels of neuronal Kir2.1, Kir3.1, and Kir6.2 were evaluated by real-time PCR and Western blot analysis from the hippocampus of an amyloid-β(Aβ)(1-42)-infused rat model of AD. Extracellular deposition of Aβ was confirmed by both histological Congo red staining and immunofluorescence analysis. Significant decreased mRNA and protein levels of Kir2.1 and Kir6.2 channels were observed in the rat model of AD, whereas no differences were found in Kir3.1 channel levels as compared with controls. Our results provide in vivo evidence that Aβ can modulate the expression of these channels, which may represent novel potential therapeutic targets in the treatment of AD.
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Affiliation(s)
- Enes Akyuz
- Department of Biophysics, Faculty of Medicine, Yozgat Bozok University, Yozgat 66100, Turkey
- Correspondence: (E.A.); (C.V.)
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
- Correspondence: (E.A.); (C.V.)
| | - Merve Beker
- Department of Medical Biology, Faculty of Medicine, Bezmialem Vakif University, Istanbul 34093, Turkey; (M.B.); (B.E.)
| | - Birsen Elibol
- Department of Medical Biology, Faculty of Medicine, Bezmialem Vakif University, Istanbul 34093, Turkey; (M.B.); (B.E.)
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Kuß J, Stallmeyer B, Goldstein M, Rinné S, Pees C, Zumhagen S, Seebohm G, Decher N, Pott L, Kienitz MC, Schulze-Bahr E. Familial Sinus Node Disease Caused by a Gain of GIRK (G-Protein Activated Inwardly Rectifying K + Channel) Channel Function. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2020; 12:e002238. [PMID: 30645171 DOI: 10.1161/circgen.118.002238] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inherited forms of sinus node dysfunction (SND) clinically include bradycardia, sinus arrest, and chronotropic incompetence and may serve as disease models to understand sinus node physiology and impulse generation. Recently, a gain-of-function mutation in the G-protein gene GNB2 led to enhanced activation of the GIRK (G-protein activated inwardly rectifying K+ channel). Thus, human cardiac GIRK channels are important for heart rate regulation and subsequently, genes encoding their subunits Kir3.1 and Kir3.4 ( KCNJ3 and KCNJ5) are potential candidates for inherited SND in human. METHODS We performed a combined approach of targeted sequencing of KCNJ3 and KCNJ5 in 52 patients with idiopathic SND and subsequent whole exome sequencing of additional family members in a genetically affected patient. A putative novel disease-associated gene variant was functionally analyzed by voltage-clamp experiments using various heterologous cell expression systems (Xenopus oocytes, CHO cells, and rat atrial cardiomyocytes). RESULTS In a 3-generation family with SND we identified a novel variant in KCNJ5 which leads to an amino acid substitution (p.Trp101Cys) in the first transmembrane domain of the Kir3.4 subunit of the cardiac GIRK channel. The identified variant cosegregated with the disease in the family and was absent in the Exome Variant Server and Exome Aggregation Consortium databases. Expression of mutant Kir3.4 (±native Kir3.1) in different heterologous cell expression systems resulted in increased GIRK currents ( IK,ACh) and a reduced inward rectification which was not compensated by intracellular spermidine. Moreover, in silico modeling of heterotetrameric mutant GIRK channels indicates a structurally altered binding site for spermine. CONCLUSIONS For the first time, an inherited gain-of-function mutation in the human GIRK3.4 causes familial human SND. The increased activity of GIRK channels is likely to lead to a sustained hyperpolarization of pacemaker cells and thereby reduces heart rate. Modulation of human GIRK channels may pave a way for further treatment of cardiac pacemaking.
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Affiliation(s)
- Johanna Kuß
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Germany (J.K., B.S., S.Z., G.S., E.S.-B.)
| | - Birgit Stallmeyer
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Germany (J.K., B.S., S.Z., G.S., E.S.-B.)
| | - Matthias Goldstein
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Germany (M.G., S.R., N.D.)
| | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Germany (M.G., S.R., N.D.)
| | - Christiane Pees
- Department of Pediatric Cardiology, University Children's Hospital Vienna, Austria (C.P.)
| | - Sven Zumhagen
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Germany (J.K., B.S., S.Z., G.S., E.S.-B.)
| | - Guiscard Seebohm
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Germany (J.K., B.S., S.Z., G.S., E.S.-B.)
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Germany (M.G., S.R., N.D.)
| | - Lutz Pott
- Department of Cardiovascular Medicine, Institute of Physiology, Ruhr-University Bochum, Germany (L.P., M.-C.K.)
| | - Marie-Cécile Kienitz
- Department of Cardiovascular Medicine, Institute of Physiology, Ruhr-University Bochum, Germany (L.P., M.-C.K.)
| | - Eric Schulze-Bahr
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Germany (J.K., B.S., S.Z., G.S., E.S.-B.)
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Szabó Z, Ujvárosy D, Ötvös T, Sebestyén V, Nánási PP. Handling of Ventricular Fibrillation in the Emergency Setting. Front Pharmacol 2020; 10:1640. [PMID: 32140103 PMCID: PMC7043313 DOI: 10.3389/fphar.2019.01640] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
Ventricular fibrillation (VF) and sudden cardiac death (SCD) are predominantly caused by channelopathies and cardiomyopathies in youngsters and coronary heart disease in the elderly. Temporary factors, e.g., electrolyte imbalance, drug interactions, and substance abuses may play an additive role in arrhythmogenesis. Ectopic automaticity, triggered activity, and reentry mechanisms are known as important electrophysiological substrates for VF determining the antiarrhythmic therapies at the same time. Emergency need for electrical cardioversion is supported by the fact that every minute without defibrillation decreases survival rates by approximately 7%–10%. Thus, early defibrillation is an essential part of antiarrhythmic emergency management. Drug therapy has its relevance rather in the prevention of sudden cardiac death, where early recognition and treatment of the underlying disease has significant importance. Cardioprotective and antiarrhythmic effects of beta blockers in patients predisposed to sudden cardiac death were highlighted in numerous studies, hence nowadays these drugs are considered to be the cornerstones of the prevention and treatment of life-threatening ventricular arrhythmias. Nevertheless, other medical therapies have not been proven to be useful in the prevention of VF. Although amiodarone has shown positive results occasionally, this was not demonstrated to be consistent. Furthermore, the potential proarrhythmic effects of drugs may also limit their applicability. Based on these unfavorable observations we highlight the importance of arrhythmia prevention, where echocardiography, electrocardiography and laboratory testing play a significant role even in the emergency setting. In the following we provide a summary on the latest developments on cardiopulmonary resuscitation, and the evaluation and preventive treatment possibilities of patients with increased susceptibility to VF and SCD.
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Affiliation(s)
- Zoltán Szabó
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Dóra Ujvárosy
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Doctoral School of Health Sciences, Faculty of Public Health, University of Debrecen, Debrecen, Hungary
| | - Tamás Ötvös
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Doctoral School of Health Sciences, Faculty of Public Health, University of Debrecen, Debrecen, Hungary
| | - Veronika Sebestyén
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Doctoral School of Health Sciences, Faculty of Public Health, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
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40
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Hassinen M, Korajoki H, Abramochkin D, Krivosheya P, Vornanen M. Transcript expression of inward rectifier potassium channels of Kir2 subfamily in Arctic marine and freshwater fish species. J Comp Physiol B 2019; 189:735-749. [PMID: 31679058 DOI: 10.1007/s00360-019-01241-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/30/2019] [Accepted: 10/16/2019] [Indexed: 02/08/2023]
Abstract
Inward rectifier K+ (Kir2) channels are critical for electrical excitability of cardiac myocytes. Here, we examine expression of Kir2 channels in the heart of three Gadiformes species, polar cod (Boreogadus saida) and navaga (Eleginus nawaga) of the Arctic Ocean and burbot (Lota lota) of the temperate lakes to find out the role of Kir2 channels in cardiac adaptation to cold. Five boreal freshwater species: brown trout (Salmo trutta fario), arctic char (Salvelinus alpinus), roach (Rutilus rutilus), perch (Perca fluviatilis) and pike (Esox lucius), and zebrafish (Danio rerio), were included for comparison. Transcript expression of genes encoding Kir2.1a, - 2.1b, - 2.2a, - 2.2b and - 2.4 was studied from atrium and ventricle of thermally acclimated or acclimatized fish by quantitative PCR. Kir2 composition in the polar cod was more diverse than in other species in that all Kir2 isoforms were relatively highly expressed. Kir2 composition of navaga and burbot differed from that of the polar cod as well as from those of other species. The relative expression of Kir2.2 transcripts, especially Kir2.2b, was higher in both atrium and ventricle of navaga and burbot (56-89% from the total Kir2 pool) than in other species (0.1-11%). Thermal acclimation induced only small changes in cardiac Kir2 transcript expression in Gadiformes species. However, Kir2.2b transcripts were upregulated in cold-acclimated navaga and burbot hearts. All in all, the cardiac Kir2 composition seems to be dependent on both phylogenetic position and thermal preference of the fish.
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Affiliation(s)
- Minna Hassinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland.
| | - Hanna Korajoki
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland
| | - Denis Abramochkin
- Department of Human and Animal Physiology, Moscow State University, Leninskiye Gory, 1, 12, Moscow, 119991, Russia.,Ural Federal University, Mira 19, Ekaterinburg, 620002, Russia.,Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | - Pavel Krivosheya
- Russian Federal Research Institute of Fisheries and Oceanography "VNIRO" Polar Branch of VNIRO, Laboratory of pelagic fish, Akademika Knipovicha st., Murmansk, 183038, Russia, Murmansk, Russia
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland
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Sevoflurane Alleviates Reperfusion Arrhythmia by Ameliorating TDR and MAPD 90 in Isolated Rat Hearts after Ischemia-Reperfusion. Anesthesiol Res Pract 2019; 2019:7910930. [PMID: 31662745 PMCID: PMC6778868 DOI: 10.1155/2019/7910930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/04/2019] [Indexed: 11/18/2022] Open
Abstract
Objective To investigate the effect of sevoflurane on the monophasic action potentials (MAPs) in isolated rat hearts after ischemia-reperfusion. Methods Twenty-four healthy SD male rats, weighing 280–320 g, were randomly divided into three groups after successful preparation of a Langendorff isolated heart perfusion model with a stabilization period perfusion of 15 min with Krebs–Henseleit (K–H) fluid (n = 8): the control group (group A, continuously perfused with K–H fluid for 105 min), the ischemia-reperfusion group (group B, continuously perfused with K–H fluid for 15 min, and then exposed to 60 min of global ischemia induced by Thomas solution followed by 30 min of reperfusion), and the sevoflurane group (group C, K–H fluid contained 1.0 MAC sevoflurane, and other procedures were same as in group B). Heart rate (HR) and MAPs including time course (MAPD50 or MAPD90) of the epicardium (Epi) and endocardium (Endo) were recorded at the time of balance perfusion for 15 min (T0), continuous perfusion for 15 min (T1), reperfusion for 15 min/continuous perfusion for 105 min (T2), and reperfusion for 30 min/continuous perfusion for 120 min (T3), and the transmural dispersion of repolarization (TDR) was calculated. The incidence of arrhythmia, time for restoration of spontaneous heart beat, and duration of arrhythmia were recorded during the period of reperfusion. Results HR in group B and group C was lower at T2 and T3 than that in group A, while that in group B was significantly lower than that in group A at T2 and T3, and HR in group C was higher than that in group B at T2 and T3 (P < 0.05). There was no difference of TDR in each group at T0 and T1 (P > 0.05), while TDR in group B was increased at T2 and T3 compared with that in group C and group A (P < 0.05). TDR in group C was decreased compared with that in group B at T2 and T3 (P < 0.05), while there was no such difference between group C and group A (P > 0.05). The time for restoration of spontaneous heart beat and duration of arrhythmia in group C were shorter than those in group B (P < 0.05), while cardiac arrhythmia scores in group B were higher than those in group C (P < 0.05). There was no difference of MAPD50 in each group (P > 0.05). The MAPD90 in group B was much longer than that in other groups at T2 and T3 (P < 0.05), while there was no such difference between group C and group A (P > 0.05). The prolonged MAPD90 at T2 and T3 in group B strikingly differed from that at T0 and T1 (P < 0.05). Nevertheless, there was no such difference in other groups at different time points (P > 0.05). Conclusion Sevoflurane alleviates reperfusion arrhythmia induced by myocardial ischemia-reperfusion through the shortening of MPAD90 in isolated rat hearts.
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Lin CX, Gu JL, Cao JM. The acute toxic effects of platinum nanoparticles on ion channels, transmembrane potentials of cardiomyocytes in vitro and heart rhythm in vivo in mice. Int J Nanomedicine 2019; 14:5595-5609. [PMID: 31413565 PMCID: PMC6660630 DOI: 10.2147/ijn.s209135] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/12/2019] [Indexed: 12/02/2022] Open
Abstract
Background Platinum nanoparticles (PtNPs) have been considered a nontoxic nanomaterial and been clinically used in cancer chemotherapy. PtNPs can also be vehicle exhausts and environmental pollutants. These situations increase the possibility of human exposure to PtNPs. However, the potential biotoxicities of PtNPs including that on cardiac electrophysiology have been poorly understood. Methods Ion channel currents of cardiomyocytes were recorded by patch clamp. Heart rhythm was monitored by electrocardiogram recording. Morphology and characteristics of PtNPs were examined by transmission electron microscopy, dynamic light scattering and electrophoretic light scattering analyses. Results In cultured neonatal mice ventricular cardiomyocytes, PtNPs with diameters 5 nm (PtNP-5) and 70 nm (PtNP-70) concentration-dependently (10–9 – 10–5 g/mL) depolarized the resting potentials, suppressed the depolarization of action potentials and delayed the repolarization of action potentials. At the ion channel level, PtNPs decreased the current densities of INa, IK1 and Ito channels, but did not affect the channel activity kinetics. In vivo, PtNP-5 and PtNP-70 dose-dependently (3–10 mg/kg, i.v.) decreased the heart rate and induced complete atrioventricular conduction block (AVB) at higher doses. Both PtNP-5 and PtNP-70 (10–9 – 10–5 g/mL) did not significantly increase the generation of ROS and leak of lactate dehydrogenase (LDH) from cardiomyocytes within 5 mins after exposure except that only very high PtNP-5 (10–5 g/mL) slightly increased LDH leak. The internalization of PtNP-5 and PtNP-70 did not occur within 5 mins but occurred 1 hr after exposure. Conclusion PtNP-5 and PtNP-70 have similar acute toxic effects on cardiac electrophysiology and can induce threatening cardiac conduction block. These acute electrophysiological toxicities of PtNPs are most likely caused by a nanoscale interference of PtNPs on ion channels at the extracellular side, rather than by oxidative damage or other slower biological processes.
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Affiliation(s)
- Cai-Xia Lin
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, People's Republic of China.,Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, People's Republic of China
| | - Jing-Li Gu
- Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, People's Republic of China
| | - Ji-Min Cao
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, People's Republic of China
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43
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Rai MK, Pai R, Prabhu MA, Pasha SW, Kedambadi RC, Kamath P, Augustine AJ, Bhavani GS, Girisha KM. Short-term response to phenytoin sodium in Andersen-Tawil syndrome-1 with a cardiac-dominant phenotype. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2018; 42:201-207. [DOI: 10.1111/pace.13569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/11/2018] [Accepted: 11/28/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Maneesh K. Rai
- Department of Cardiology; Kasturba Medical College, Manipal Academy of Higher Education; Mangalore Karnataka India
| | - Rohith Pai
- Department of Neurology; Kasturba Medical College, Manipal Academy of Higher Education; Mangalore Karnataka India
| | - Mukund A. Prabhu
- Department of Cardiology; Kasturba Medical College, Manipal Academy of Higher Education; Mangalore Karnataka India
| | - Syed Waleem Pasha
- Department of Cardiology; Kasturba Medical College, Manipal Academy of Higher Education; Mangalore Karnataka India
| | - Rakshith C. Kedambadi
- Department of Neurology; Kasturba Medical College, Manipal Academy of Higher Education; Mangalore Karnataka India
| | - Padmanabh Kamath
- Department of Cardiology; Kasturba Medical College, Manipal Academy of Higher Education; Mangalore Karnataka India
| | - Alfred J. Augustine
- Department of Surgery; Kasturba Medical College, Manipal Academy of Higher Education; Mangalore Karnataka India
| | - Gangham SriLakshmi Bhavani
- Department of Medical Genetics; Kasturba Medical College, Manipal Academy of Higher Education; Manipal Karnataka India
| | - Katta M. Girisha
- Department of Medical Genetics; Kasturba Medical College, Manipal Academy of Higher Education; Manipal Karnataka India
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Nikouee A, Uchida K, Moench I, Lopatin AN. Cholesterol Protects Against Acute Stress-Induced T-Tubule Remodeling in Mouse Ventricular Myocytes. Front Physiol 2018; 9:1516. [PMID: 30483142 PMCID: PMC6240595 DOI: 10.3389/fphys.2018.01516] [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] [Received: 05/30/2018] [Accepted: 10/09/2018] [Indexed: 12/28/2022] Open
Abstract
Efficient excitation-contraction coupling in ventricular myocytes depends critically on the presence of the t-tubular network. It has been recently demonstrated that cholesterol, a major component of the lipid bilayer, plays an important role in long-term maintenance of the integrity of t-tubular system although mechanistic understanding of underlying processes is essentially lacking. Accordingly, in this study we investigated the contribution of membrane cholesterol to t-tubule remodeling in response to acute hyposmotic stress. Experiments were performed using isolated left ventricular cardiomyocytes from adult mice. Depletion and restoration of membrane cholesterol was achieved by applying methyl-β-cyclodextrin (MβCD) and water soluble cholesterol (WSC), respectively, and t-tubule remodeling in response to acute hyposmotic stress was assessed using fluorescent dextran trapping assay and by measuring t-tubule dependent IK1 tail current (IK1,tail). The amount of dextran trapped in t-tubules sealed in response to stress was significantly increased when compared to control cells, and reintroduction of cholesterol to cells treated with MβCD restored the amount of trapped dextran to control values. Alternatively, application of WSC to normal cells significantly reduced the amount of trapped dextran further suggesting the protective effect of cholesterol. Importantly, modulation of membrane cholesterol (without osmotic stress) led to significant changes in various parameters of IK1, tail strongly suggesting significant but essentially hidden remodeling of t-tubules prior to osmotic stress. Results of this study demonstrate that modulation of the level of membrane cholesterol has significant effects on the susceptibility of cardiac t-tubules to acute hyposmotic stress.
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Affiliation(s)
- Azadeh Nikouee
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Keita Uchida
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Ian Moench
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Anatoli N Lopatin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
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Pérez-Hernández M, Matamoros M, Alfayate S, Nieto-Marín P, Utrilla RG, Tinaquero D, de Andrés R, Crespo T, Ponce-Balbuena D, Willis BC, Jiménez-Vazquez EN, Guerrero-Serna G, da Rocha AM, Campbell K, Herron TJ, Díez-Guerra FJ, Tamargo J, Jalife J, Caballero R, Delpón E. Brugada syndrome trafficking-defective Nav1.5 channels can trap cardiac Kir2.1/2.2 channels. JCI Insight 2018; 3:96291. [PMID: 30232268 DOI: 10.1172/jci.insight.96291] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/03/2018] [Indexed: 12/28/2022] Open
Abstract
Cardiac Nav1.5 and Kir2.1-2.3 channels generate Na (INa) and inward rectifier K (IK1) currents, respectively. The functional INa and IK1 interplay is reinforced by the positive and reciprocal modulation between Nav15 and Kir2.1/2.2 channels to strengthen the control of ventricular excitability. Loss-of-function mutations in the SCN5A gene, which encodes Nav1.5 channels, underlie several inherited arrhythmogenic syndromes, including Brugada syndrome (BrS). We investigated whether the presence of BrS-associated mutations alters IK1 density concomitantly with INa density. Results obtained using mouse models of SCN5A haploinsufficiency, and the overexpression of native and mutated Nav1.5 channels in expression systems - rat ventricular cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) - demonstrated that endoplasmic reticulum (ER) trafficking-defective Nav1.5 channels significantly decreased IK1, since they did not positively modulate Kir2.1/2.2 channels. Moreover, Golgi trafficking-defective Nav1.5 mutants produced a dominant negative effect on Kir2.1/2.2 and thus an additional IK1 reduction. Moreover, ER trafficking-defective Nav1.5 channels can be partially rescued by Kir2.1/2.2 channels through an unconventional secretory route that involves Golgi reassembly stacking proteins (GRASPs). Therefore, cardiac excitability would be greatly affected in subjects harboring Nav1.5 mutations with Golgi trafficking defects, since these mutants can concomitantly trap Kir2.1/2.2 channels, thus unexpectedly decreasing IK1 in addition to INa.
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Affiliation(s)
- Marta Pérez-Hernández
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Marcos Matamoros
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Silvia Alfayate
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Paloma Nieto-Marín
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Raquel G Utrilla
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - David Tinaquero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Raquel de Andrés
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Teresa Crespo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Daniela Ponce-Balbuena
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - B Cicero Willis
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Eric N Jiménez-Vazquez
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Guadalupe Guerrero-Serna
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Andre M da Rocha
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Katherine Campbell
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Todd J Herron
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - F Javier Díez-Guerra
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - José Jalife
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA.,Fundación Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Eva Delpón
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
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Salazar-Fajardo PD, Aréchiga-Figueroa IA, López-Serrano AL, Rodriguez-Elias JC, Alamilla J, Sánchez-Chapula JA, Tristani-Firouzi M, Navarro-Polanco RA, Moreno-Galindo EG. The voltage-sensitive cardiac M 2 muscarinic receptor modulates the inward rectification of the G protein-coupled, ACh-gated K + current. Pflugers Arch 2018; 470:1765-1776. [PMID: 30155776 DOI: 10.1007/s00424-018-2196-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/28/2018] [Accepted: 08/13/2018] [Indexed: 11/25/2022]
Abstract
The acetylcholine (ACh)-gated inwardly rectifying K+ current (IKACh) plays a vital role in cardiac excitability by regulating heart rate variability and vulnerability to atrial arrhythmias. These crucial physiological contributions are determined principally by the inwardly rectifying nature of IKACh. Here, we investigated the relative contribution of two distinct mechanisms of IKACh inward rectification measured in atrial myocytes: a rapid component due to KACh channel block by intracellular Mg2+ and polyamines; and a time- and concentration-dependent mechanism. The time- and ACh concentration-dependent inward rectification component was eliminated when IKACh was activated by GTPγS, a compound that bypasses the muscarinic-2 receptor (M2R) and directly stimulates trimeric G proteins to open KACh channels. Moreover, the time-dependent component of IKACh inward rectification was also eliminated at ACh concentrations that saturate the receptor. These observations indicate that the time- and concentration-dependent rectification mechanism is an intrinsic property of the receptor, M2R; consistent with our previous work demonstrating that voltage-dependent conformational changes in the M2R alter the receptor affinity for ACh. Our analysis of the initial and time-dependent components of IKACh indicate that rapid Mg2+-polyamine block accounts for 60-70% of inward rectification, with M2R voltage sensitivity contributing 30-40% at sub-saturating ACh concentrations. Thus, while both inward rectification mechanisms are extrinsic to the KACh channel, to our knowledge, this is the first description of extrinsic inward rectification of ionic current attributable to an intrinsic voltage-sensitive property of a G protein-coupled receptor.
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Affiliation(s)
- Pedro D Salazar-Fajardo
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Colonia Villa San Sebastián, C.P, 28045, Colima, COL, Mexico
| | - Iván A Aréchiga-Figueroa
- CONACyT, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico
| | - Ana Laura López-Serrano
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Colonia Villa San Sebastián, C.P, 28045, Colima, COL, Mexico
| | - Julio C Rodriguez-Elias
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Colonia Villa San Sebastián, C.P, 28045, Colima, COL, Mexico
| | - Javier Alamilla
- CONACyT, Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, COL, Mexico
| | - José A Sánchez-Chapula
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Colonia Villa San Sebastián, C.P, 28045, Colima, COL, Mexico
| | - Martin Tristani-Firouzi
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Ricardo A Navarro-Polanco
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Colonia Villa San Sebastián, C.P, 28045, Colima, COL, Mexico.
| | - Eloy G Moreno-Galindo
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Colonia Villa San Sebastián, C.P, 28045, Colima, COL, Mexico.
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Kodama T, Okada M, Yamawaki H. Mechanisms underlying the relaxation by A484954, a eukaryotic elongation factor 2 kinase inhibitor, in rat isolated mesenteric artery. J Pharmacol Sci 2018; 137:86-92. [PMID: 29778449 DOI: 10.1016/j.jphs.2018.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/22/2018] [Accepted: 04/24/2018] [Indexed: 12/13/2022] Open
Abstract
Eukaryotic elongation factor 2 kinase (eEF2K) is a calmodulin-related protein kinase which regulates protein translation. A484954 is an inhibitor of eEF2K. In the present study, we investigated the acute effects of A484954 on contractility of isolated blood vessels. Isometric contraction of rat isolated aorta and main branch of superior mesenteric artery (MA) was measured. Expression of an inward rectifier K+ (Kir) channel subtype mRNA and protein was examined. A484954 caused relaxation in endothelium-intact [E (+)] and -denuded [E (-)] aorta or MA precontracted with noradrenaline (NA). The relaxation was higher in MA than aorta. The relaxation was partially inhibited by a nitric oxide (NO) synthase inhibitor, NG-nitro-l-arginine methyl ester (300 μM) in E (+) MA. The relaxation was significantly smaller in MA precontracted with high K+ than NA. The A484954-induced relaxation was significantly inhibited by a Kir channel blocker, BaCl2 (1 mM) compared with vehicle control in E (-) MA. Expression of Kir2.2 mRNA and protein was significantly higher in MA than aorta. We for the first time revealed that A484954 induces relaxation through opening smooth muscle Kir (Kir2.2) channel and through endothelium-derived NO in MA.
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Affiliation(s)
- Tomoko Kodama
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 Bancho 35-1, Towada City, Aomori, 034-8628, Japan
| | - Muneyoshi Okada
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 Bancho 35-1, Towada City, Aomori, 034-8628, Japan
| | - Hideyuki Yamawaki
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23 Bancho 35-1, Towada City, Aomori, 034-8628, Japan.
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48
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Amarillo Y, Tissone AI, Mato G, Nadal MS. Inward rectifier potassium current I Kir promotes intrinsic pacemaker activity of thalamocortical neurons. J Neurophysiol 2018; 119:2358-2372. [PMID: 29561202 DOI: 10.1152/jn.00867.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Slow repetitive burst firing by hyperpolarized thalamocortical (TC) neurons correlates with global slow rhythms (<4 Hz), which are the physiological oscillations during non-rapid eye movement sleep or pathological oscillations during idiopathic epilepsy. The pacemaker activity of TC neurons depends on the expression of several subthreshold conductances, which are modulated in a behaviorally dependent manner. Here we show that upregulation of the small and neglected inward rectifier potassium current IKir induces repetitive burst firing at slow and delta frequency bands. We demonstrate this in mouse TC neurons in brain slices by manipulating the Kir maximum conductance with dynamic clamp. We also performed a thorough theoretical analysis that explains how the unique properties of IKir enable this current to induce slow periodic bursting in TC neurons. We describe a new ionic mechanism based on the voltage- and time-dependent interaction of IKir and hyperpolarization-activated cationic current Ih that endows TC neurons with the ability to oscillate spontaneously at very low frequencies, even below 0.5 Hz. Bifurcation analysis of conductance-based models of increasing complexity demonstrates that IKir induces bistability of the membrane potential at the same time that it induces sustained oscillations in combination with Ih and increases the robustness of low threshold-activated calcium current IT-mediated oscillations. NEW & NOTEWORTHY The strong inwardly rectifying potassium current IKir of thalamocortical neurons displays a region of negative slope conductance in the current-voltage relationship that generates potassium currents activated by hyperpolarization. Bifurcation analysis shows that IKir induces bistability of the membrane potential; generates sustained subthreshold oscillations by interacting with the hyperpolarization-activated cationic current Ih; and increases the robustness of oscillations mediated by the low threshold-activated calcium current IT. Upregulation of IKir in thalamocortical neurons induces repetitive burst firing at slow and delta frequency bands (<4 Hz).
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Affiliation(s)
- Yimy Amarillo
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Carlos de Bariloche, Río Negro, Argentina.,Gerencia de Área Investigación y Aplicaciones no Nucleares, Gerencia de Física, Departamento Sistemas Complejos y Altas Energías, División Física Estadística e Interdisciplinaria, Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina
| | - Angela I Tissone
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Carlos de Bariloche, Río Negro, Argentina.,Gerencia de Área Investigación y Aplicaciones no Nucleares, Gerencia de Física, Departamento Sistemas Complejos y Altas Energías, División Física Estadística e Interdisciplinaria, Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Universidad Nacional del Comahue, Centro Regional Universitario Bariloche, San Carlos de Bariloche, Río Negro, Argentina
| | - Germán Mato
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Carlos de Bariloche, Río Negro, Argentina.,Gerencia de Área Investigación y Aplicaciones no Nucleares, Gerencia de Física, Departamento Sistemas Complejos y Altas Energías, División Física Estadística e Interdisciplinaria, Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina
| | - Marcela S Nadal
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Carlos de Bariloche, Río Negro, Argentina.,Gerencia de Área Investigación y Aplicaciones no Nucleares, Gerencia de Física, Departamento Sistemas Complejos y Altas Energías, División Física Estadística e Interdisciplinaria, Centro Atómico Bariloche, San Carlos de Bariloche, Río Negro, Argentina.,Universidad Nacional del Comahue, Centro Regional Universitario Bariloche, San Carlos de Bariloche, Río Negro, Argentina
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49
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Horváth A, Lemoine MD, Löser A, Mannhardt I, Flenner F, Uzun AU, Neuber C, Breckwoldt K, Hansen A, Girdauskas E, Reichenspurner H, Willems S, Jost N, Wettwer E, Eschenhagen T, Christ T. Low Resting Membrane Potential and Low Inward Rectifier Potassium Currents Are Not Inherent Features of hiPSC-Derived Cardiomyocytes. Stem Cell Reports 2018; 10:822-833. [PMID: 29429959 PMCID: PMC5918194 DOI: 10.1016/j.stemcr.2018.01.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 01/12/2018] [Accepted: 01/15/2018] [Indexed: 11/18/2022] Open
Abstract
Human induced pluripotent stem cell (hiPSC) cardiomyocytes (CMs) show less negative resting membrane potential (RMP), which is attributed to small inward rectifier currents (IK1). Here, IK1 was measured in hiPSC-CMs (proprietary and commercial cell line) cultured as monolayer (ML) or 3D engineered heart tissue (EHT) and, for direct comparison, in CMs from human right atrial (RA) and left ventricular (LV) tissue. RMP was measured in isolated cells and intact tissues. IK1 density in ML- and EHT-CMs from the proprietary line was similar to LV and RA, respectively. IK1 density in EHT-CMs from the commercial line was 2-fold smaller than in the proprietary line. RMP in EHT of both lines was similar to RA and LV. Repolarization fraction and IK,ACh response discriminated best between RA and LV and indicated predominantly ventricular phenotype in hiPSC-CMs/EHT. The data indicate that IK1 is not necessarily low in hiPSC-CMs, and technical issues may underlie low RMP in hiPSC-CMs.
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Affiliation(s)
- András Horváth
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany; Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, 6721 Szeged, Hungary
| | - Marc D Lemoine
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; Department of Cardiology-Electrophysiology, University Heart Center Hamburg, 20246 Hamburg, Germany
| | - Alexandra Löser
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Ingra Mannhardt
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Frederik Flenner
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Ahmet Umur Uzun
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Christiane Neuber
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Kaja Breckwoldt
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Arne Hansen
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Evaldas Girdauskas
- Department of Cardiovascular Surgery, University Heart Center Hamburg, 20246 Hamburg, Germany
| | - Hermann Reichenspurner
- Department of Cardiovascular Surgery, University Heart Center Hamburg, 20246 Hamburg, Germany
| | - Stephan Willems
- Department of Cardiology-Electrophysiology, University Heart Center Hamburg, 20246 Hamburg, Germany
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, 6721 Szeged, Hungary
| | - Erich Wettwer
- Institute of Pharmacology, University Duisburg-Essen, 45122 Essen, Germany
| | - Thomas Eschenhagen
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Torsten Christ
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Institut für Experimentelle Pharmakologie und Toxikologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany.
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50
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Ponce-Balbuena D, Guerrero-Serna G, Valdivia CR, Caballero R, Diez-Guerra FJ, Jiménez-Vázquez EN, Ramírez RJ, Monteiro da Rocha A, Herron TJ, Campbell KF, Willis BC, Alvarado FJ, Zarzoso M, Kaur K, Pérez-Hernández M, Matamoros M, Valdivia HH, Delpón E, Jalife J. Cardiac Kir2.1 and Na V1.5 Channels Traffic Together to the Sarcolemma to Control Excitability. Circ Res 2018. [PMID: 29514831 DOI: 10.1161/circresaha.117.311872] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RATIONALE In cardiomyocytes, NaV1.5 and Kir2.1 channels interact dynamically as part of membrane bound macromolecular complexes. OBJECTIVE The objective of this study was to test whether NaV1.5 and Kir2.1 preassemble during early forward trafficking and travel together to common membrane microdomains. METHODS AND RESULTS In patch-clamp experiments, coexpression of trafficking-deficient mutants Kir2.1Δ314-315 or Kir2.1R44A/R46A with wild-type (WT) NaV1.5WT in heterologous cells reduced inward sodium current compared with NaV1.5WT alone or coexpressed with Kir2.1WT. In cell surface biotinylation experiments, expression of Kir2.1Δ314-315 reduced NaV1.5 channel surface expression. Glycosylation analysis suggested that NaV1.5WT and Kir2.1WT channels associate early in their biosynthetic pathway, and fluorescence recovery after photobleaching experiments demonstrated that coexpression with Kir2.1 increased cytoplasmic mobility of NaV1.5WT, and vice versa, whereas coexpression with Kir2.1Δ314-315 reduced mobility of both channels. Viral gene transfer of Kir2.1Δ314-315 in adult rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes reduced inward rectifier potassium current and inward sodium current, maximum diastolic potential and action potential depolarization rate, and increased action potential duration. On immunostaining, the AP1 (adaptor protein complex 1) colocalized with NaV1.5WT and Kir2.1WT within areas corresponding to t-tubules and intercalated discs. Like Kir2.1WT, NaV1.5WT coimmunoprecipitated with AP1. Site-directed mutagenesis revealed that NaV1.5WT channels interact with AP1 through the NaV1.5Y1810 residue, suggesting that, like for Kir2.1WT, AP1 can mark NaV1.5 channels for incorporation into clathrin-coated vesicles at the trans-Golgi. Silencing the AP1 ϒ-adaptin subunit in human induced pluripotent stem cell-derived cardiomyocytes reduced inward rectifier potassium current, inward sodium current, and maximum diastolic potential and impaired rate-dependent action potential duration adaptation. CONCLUSIONS The NaV1.5-Kir2.1 macromolecular complex pre-assembles early in the forward trafficking pathway. Therefore, disruption of Kir2.1 trafficking in cardiomyocytes affects trafficking of NaV1.5, which may have important implications in the mechanisms of arrhythmias in inheritable cardiac diseases.
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Affiliation(s)
- Daniela Ponce-Balbuena
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Guadalupe Guerrero-Serna
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Carmen R Valdivia
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Ricardo Caballero
- Department of Pharmacology, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.).,Instituto de Investigación Sanitaria Gregorio Marañón, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.)
| | - F Javier Diez-Guerra
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Universidad Autónoma de Madrid, Spain (F.J.D.-G.)
| | - Eric N Jiménez-Vázquez
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Rafael J Ramírez
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - André Monteiro da Rocha
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Todd J Herron
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Katherine F Campbell
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - B Cicero Willis
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | | | - Manuel Zarzoso
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Kuljeet Kaur
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.)
| | - Marta Pérez-Hernández
- Department of Pharmacology, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.).,Instituto de Investigación Sanitaria Gregorio Marañón, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.)
| | - Marcos Matamoros
- Department of Pharmacology, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.).,Instituto de Investigación Sanitaria Gregorio Marañón, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.)
| | - Héctor H Valdivia
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.).,Department of Molecular and Integrative Physiology (F.J.A., H.H.V.)
| | - Eva Delpón
- Department of Pharmacology, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.).,Instituto de Investigación Sanitaria Gregorio Marañón, School of Medicine, Universidad Complutense, Madrid, Spain (R.C., M.P.-H., M.M., E.D.)
| | - José Jalife
- From the Department of Internal Medicine and Center for Arrhythmia Research (D.P.-B., G.G.-S., C.R.V., E.N.J.-V., R.J.R., A.M.d.R., T.J.H., K.F.C., B.C.W., M.Z., K.K., H.H.V., J.J.) .,University of Michigan, Ann Arbor; Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.).,CIBERV, Madrid, Spain (J.J.)
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