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Saint-Martin Willer A, Santos-Gomes J, Adão R, Brás-Silva C, Eyries M, Pérez-Vizcaino F, Capuano V, Montani D, Antigny F. Physiological and pathophysiological roles of the KCNK3 potassium channel in the pulmonary circulation and the heart. J Physiol 2023; 601:3717-3737. [PMID: 37477289 DOI: 10.1113/jp284936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 07/04/2023] [Indexed: 07/22/2023] Open
Abstract
Potassium channel subfamily K member 3 (KCNK3), encoded by the KCNK3 gene, is part of the two-pore domain potassium channel family, constitutively active at resting membrane potentials in excitable cells, including smooth muscle and cardiac cells. Several physiological and pharmacological mediators, such as intracellular signalling pathways, extracellular pH, hypoxia and anaesthetics, regulate KCNK3 channel function. Recent studies show that modulation of KCNK3 channel expression and function strongly influences pulmonary vascular cell and cardiomyocyte function. The altered activity of KCNK3 in pathological situations such as atrial fibrillation, pulmonary arterial hypertension and right ventricular dysfunction demonstrates the crucial role of KCNK3 in cardiovascular homeostasis. Furthermore, loss of function variants of KCNK3 have been identified in patients suffering from pulmonary arterial hypertension and atrial fibrillation. This review focuses on current knowledge of the role of the KCNK3 channel in pulmonary circulation and the heart, in healthy and pathological conditions.
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Affiliation(s)
- Anaïs Saint-Martin Willer
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 'Hypertension Pulmonaire: Physiopathologie et Innovation Thérapeutique', Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Joana Santos-Gomes
- Cardiovascular R&D Centre-UnIC@RISE, Department of Surgery and Physiology, Faculty of Medicine of the University of Porto, Porto, Portugal
| | - Rui Adão
- Cardiovascular R&D Centre-UnIC@RISE, Department of Surgery and Physiology, Faculty of Medicine of the University of Porto, Porto, Portugal
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
- CIBER Enfermedades Respiratorias (Ciberes), Madrid, Spain
| | - Carmen Brás-Silva
- Cardiovascular R&D Centre-UnIC@RISE, Department of Surgery and Physiology, Faculty of Medicine of the University of Porto, Porto, Portugal
| | - Mélanie Eyries
- Département de génétique, Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Sorbonne Université, Paris, France
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France
| | - Francisco Pérez-Vizcaino
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
- CIBER Enfermedades Respiratorias (Ciberes), Madrid, Spain
| | - Véronique Capuano
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 'Hypertension Pulmonaire: Physiopathologie et Innovation Thérapeutique', Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - David Montani
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 'Hypertension Pulmonaire: Physiopathologie et Innovation Thérapeutique', Hôpital Marie Lannelongue, Le Plessis-Robinson, France
- Assistance Publique - Hôpitaux de Paris (AP-HP), Service de Pneumologie et Soins Intensifs Respiratoires, Centre de Référence de l'Hypertension Pulmonaire, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Fabrice Antigny
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 'Hypertension Pulmonaire: Physiopathologie et Innovation Thérapeutique', Hôpital Marie Lannelongue, Le Plessis-Robinson, France
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Kraft M, Büscher A, Wiedmann F, L’hoste Y, Haefeli WE, Frey N, Katus HA, Schmidt C. Current Drug Treatment Strategies for Atrial Fibrillation and TASK-1 Inhibition as an Emerging Novel Therapy Option. Front Pharmacol 2021; 12:638445. [PMID: 33897427 PMCID: PMC8058608 DOI: 10.3389/fphar.2021.638445] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia with a prevalence of up to 4% and an upwards trend due to demographic changes. It is associated with an increase in mortality and stroke incidences. While stroke risk can be significantly reduced through anticoagulant therapy, adequate treatment of other AF related symptoms remains an unmet medical need in many cases. Two main treatment strategies are available: rate control that modulates ventricular heart rate and prevents tachymyopathy as well as rhythm control that aims to restore and sustain sinus rhythm. Rate control can be achieved through drugs or ablation of the atrioventricular node, rendering the patient pacemaker-dependent. For rhythm control electrical cardioversion and pharmacological cardioversion can be used. While electrical cardioversion requires fasting and sedation of the patient, antiarrhythmic drugs have other limitations. Most antiarrhythmic drugs carry a risk for pro-arrhythmic effects and are contraindicated in patients with structural heart diseases. Furthermore, catheter ablation of pulmonary veins can be performed with its risk of intraprocedural complications and varying success. In recent years TASK-1 has been introduced as a new target for AF therapy. Upregulation of TASK-1 in AF patients contributes to prolongation of the action potential duration. In a porcine model of AF, TASK-1 inhibition by gene therapy or pharmacological compounds induced cardioversion to sinus rhythm. The DOxapram Conversion TO Sinus rhythm (DOCTOS)-Trial will reveal whether doxapram, a potent TASK-1 inhibitor, can be used for acute cardioversion of persistent and paroxysmal AF in patients, potentially leading to a new treatment option for AF.
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Affiliation(s)
- Manuel Kraft
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Antonius Büscher
- Clinic for Cardiology II: Electrophysiology, University Hospital Münster, Münster, Germany
| | - Felix Wiedmann
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Yannick L’hoste
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Walter E. Haefeli
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
| | - Norbert Frey
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Hugo A. Katus
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
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Schmidt C, Wiedmann F, Beyersdorf C, Zhao Z, El-Battrawy I, Lan H, Szabo G, Li X, Lang S, Korkmaz-Icöz S, Rapti K, Jungmann A, Ratte A, Müller OJ, Karck M, Seemann G, Akin I, Borggrefe M, Zhou XB, Katus HA, Thomas D. Genetic Ablation of TASK-1 (Tandem of P Domains in a Weak Inward Rectifying K + Channel-Related Acid-Sensitive K + Channel-1) (K 2P3.1) K + Channels Suppresses Atrial Fibrillation and Prevents Electrical Remodeling. Circ Arrhythm Electrophysiol 2019; 12:e007465. [PMID: 31514528 DOI: 10.1161/circep.119.007465] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Despite an increasing understanding of atrial fibrillation (AF) pathophysiology, translation into mechanism-based treatment options is lacking. In atrial cardiomyocytes of patients with chronic AF, expression, and function of tandem of P domains in a weak inward rectifying TASK-1 (K+ channel-related acid-sensitive K+ channel-1) (K2P3.1) atrial-specific 2-pore domain potassium channels is enhanced, resulting in action potential duration shortening. TASK-1 channel inhibition prevents action potential duration shortening to maintain values observed among sinus rhythm subjects. The present preclinical study used a porcine AF model to evaluate the antiarrhythmic efficacy of TASK-1 inhibition by adeno-associated viral anti-TASK-1-siRNA (small interfering RNA) gene transfer. METHODS AF was induced in domestic pigs by atrial burst stimulation via implanted pacemakers. Adeno-associated viral vectors carrying anti-TASK-1-siRNA were injected into both atria to suppress TASK-1 channel expression. After the 14-day follow-up period, porcine cardiomyocytes were isolated from right and left atrium, followed by electrophysiological and molecular characterization. RESULTS AF was associated with increased TASK-1 transcript, protein and ion current levels leading to shortened action potential duration in atrial cardiomyocytes compared to sinus rhythm controls, similar to previous findings in humans. Anti-TASK-1 adeno-associated viral application significantly reduced AF burden in comparison to untreated AF pigs. Antiarrhythmic effects of anti-TASK-1-siRNA were associated with reduction of TASK-1 currents and prolongation of action potential durations in atrial cardiomyocytes to sinus rhythm values. Conclusions Adeno-associated viral-based anti-TASK-1 gene therapy suppressed AF and corrected cellular electrophysiological remodeling in a porcine model of AF. Suppression of AF through selective reduction of TASK-1 currents represents a new option for antiarrhythmic therapy.
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Affiliation(s)
- Constanze Schmidt
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,HCR (Heidelberg Center for Heart Rhythm Disorders) (C.S., F.W., C.B., A.R., H.A.K., D.T.), University Hospital Heidelberg
| | - Felix Wiedmann
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,HCR (Heidelberg Center for Heart Rhythm Disorders) (C.S., F.W., C.B., A.R., H.A.K., D.T.), University Hospital Heidelberg
| | - Christoph Beyersdorf
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,HCR (Heidelberg Center for Heart Rhythm Disorders) (C.S., F.W., C.B., A.R., H.A.K., D.T.), University Hospital Heidelberg
| | - Zhihan Zhao
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Ibrahim El-Battrawy
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Huan Lan
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Gabor Szabo
- Department of Cardiac Surgery (G. Szabo, S.K.-I., M.K.), University Hospital Heidelberg
| | - Xin Li
- First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Siegfried Lang
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Sevil Korkmaz-Icöz
- Department of Cardiac Surgery (G. Szabo, S.K.-I., M.K.), University Hospital Heidelberg
| | - Kleopatra Rapti
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg
| | - Andreas Jungmann
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg
| | - Antonius Ratte
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,HCR (Heidelberg Center for Heart Rhythm Disorders) (C.S., F.W., C.B., A.R., H.A.K., D.T.), University Hospital Heidelberg
| | - Oliver J Müller
- Department of Internal Medicine III (O.J.M.), University of Kiel.,DZHK, partner site Hamburg/Kiel/Lübeck (O.J.M.), University of Kiel
| | - Matthias Karck
- Department of Cardiac Surgery (G. Szabo, S.K.-I., M.K.), University Hospital Heidelberg
| | - Gunnar Seemann
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen (G. Seemann).,Faculty of Medicine, Albert-Ludwigs University of Freiburg, Germany (G. Seemann)
| | - Ibrahim Akin
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Martin Borggrefe
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Xiao-Bo Zhou
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,First Department of Medicine, University Medical Center Mannheim (Z.Z., I.E.-B., H.L., X.L., S.L., I.A., M.B., X.-B.Z.)
| | - Hugo A Katus
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg.,HCR (Heidelberg Center for Heart Rhythm Disorders) (C.S., F.W., C.B., A.R., H.A.K., D.T.), University Hospital Heidelberg
| | - Dierk Thomas
- Department of Cardiology (C.S., F.W., C.B., K.R., A.J., A.R., H.A.K., D.T.), University of Heidelberg.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim (C.S., F.W., C.B., Z.Z., I.E.-B., H.L., S.L., K.R., A.J., A.R., I.A., M.B., X.-B.Z., H.A.K., D.T.), University of Heidelberg
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Peyronnet R, Ravens U. Atria-selective antiarrhythmic drugs in need of alliance partners. Pharmacol Res 2019; 145:104262. [PMID: 31059791 DOI: 10.1016/j.phrs.2019.104262] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/30/2019] [Accepted: 05/03/2019] [Indexed: 12/15/2022]
Abstract
Atria-selective antiarrhythmic drugs in need of alliance partners. Guideline-based treatment of atrial fibrillation (AF) comprises prevention of thromboembolism and stroke, as well as antiarrhythmic therapy by drugs, electrical rhythm conversion, ablation and surgical procedures. Conventional antiarrhythmic drugs are burdened with unwanted side effects including a propensity of triggering life-threatening ventricular fibrillation. In order to solve this therapeutic dilemma, 'atria-selective' antiarrhythmic drugs have been developed for the treatment of supraventricular arrhythmias. These drugs are designed to aim at atrial targets, taking advantage of differences in atrial and ventricular ion channel expression and function. However it is not clear, whether such drugs are sufficiently antiarrhythmic or whether they are in need of an alliance partner for clinical efficacy. Atria-selective Na+ channel blockers display fast dissociation kinetics and high binding affinity to inactivated channels. Compounds targeting atria-selective K+ channels include blockers of ultra rapid delayed rectifier (Kv1.5) or acetylcholine-activated inward rectifier K+ channels (Kir3.x), inward rectifying K+ channels (Kir2.x), Ca2+-activated K+ channels of small conductance (SK), weakly rectifying two-pore domain K+ channels (K2P), and transient receptor potential channels (TRP). Despite good antiarrhythmic data from in-vitro and animal model experiments, clinical efficacy of atria-selective antiarrhythmic drugs remains to be demonstrated. In the present review we will briefly summarize the novel compounds and their proposed antiarrhythmic action. In addition, we will discuss the evidence for putative improvement of antiarrhythmic efficacy and potency by addressing multiple pathophysiologically relevant targets as possible alliance partners.
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Affiliation(s)
- Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ursula Ravens
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany; Institute of Physiology, Medical Faculty TU Dresden, Dresden, Germany.
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5
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Jones SA, Walton RD, Morton M, Lancaster MK. K 2p 3.1 protein is expressed as a transmural gradient across the rat left ventricular free wall. J Cardiovasc Electrophysiol 2018; 30:383-391. [PMID: 30516300 PMCID: PMC6446730 DOI: 10.1111/jce.13805] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/08/2018] [Accepted: 11/15/2018] [Indexed: 12/25/2022]
Abstract
Introduction K2p3.1, also known as TASK‐1, is a twin‐pore acid‐sensitive repolarizing K+ channel, responsible for a background potassium current that significantly contributes to setting the resting membrane potential of cardiac myocytes. Inhibition of IK2p3.1 alters cardiac repolarization and is proarrhythmogenic. In this study, we have examined the expression of K2p3.1 and function of this channel in tissue and myocytes from across the left ventricular free wall. Methods and Results Using fluorescence immunocytochemistry, the expression of K2p3.1 protein in myocytes from the subendocardial region was found to be twice (205% ± 13.5%) that found in myocytes from the subepicardial region of the left ventricle (100% ± 5.3%). The left ventricular free wall exhibited a marked transmural gradient of K2p3.1 protein expression. Western blot analysis confirmed significantly higher K2p3.1 protein expression in subendocardial tissue (156% ± 2.5%) than subepicardial tissue (100% ± 5.0%). However, there was no difference in K2p3.1 messenger RNA expression. Whole‐cell patch clamp identified IK2p3.1 current density to be significantly greater in myocytes isolated from the subendocardium (7.66 ± 0.53 pA/pF) compared with those from the subepicardium (3.47 ± 0.74 pA/pF). Conclusions This is the first study to identify a transmural gradient of K2p3.1 in the left ventricle. This gradient has implications for understanding ventricular arrhythmogenesis under conditions of ischemia but also in response to other modulatory factors, such as adrenergic stimulation and the presence of anesthetics that inhibits or activates this channel.
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Affiliation(s)
- Sandra A Jones
- Department of Biomedical Sciences, Department Faculty of Health Sciences, University of Hull, Hull, UK
| | - Richard D Walton
- Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Université de Bordeaux, Bordeaux, France.,Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Fondation Bordeaux Université, Bordeaux, France
| | | | - Matthew K Lancaster
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, UK
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Vagos M, van Herck IGM, Sundnes J, Arevalo HJ, Edwards AG, Koivumäki JT. Computational Modeling of Electrophysiology and Pharmacotherapy of Atrial Fibrillation: Recent Advances and Future Challenges. Front Physiol 2018; 9:1221. [PMID: 30233399 PMCID: PMC6131668 DOI: 10.3389/fphys.2018.01221] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/13/2018] [Indexed: 12/19/2022] Open
Abstract
The pathophysiology of atrial fibrillation (AF) is broad, with components related to the unique and diverse cellular electrophysiology of atrial myocytes, structural complexity, and heterogeneity of atrial tissue, and pronounced disease-associated remodeling of both cells and tissue. A major challenge for rational design of AF therapy, particularly pharmacotherapy, is integrating these multiscale characteristics to identify approaches that are both efficacious and independent of ventricular contraindications. Computational modeling has long been touted as a basis for achieving such integration in a rapid, economical, and scalable manner. However, computational pipelines for AF-specific drug screening are in their infancy, and while the field is progressing quite rapidly, major challenges remain before computational approaches can fill the role of workhorse in rational design of AF pharmacotherapies. In this review, we briefly detail the unique aspects of AF pathophysiology that determine requirements for compounds targeting AF rhythm control, with emphasis on delimiting mechanisms that promote AF triggers from those providing substrate or supporting reentry. We then describe modeling approaches that have been used to assess the outcomes of drugs acting on established AF targets, as well as on novel promising targets including the ultra-rapidly activating delayed rectifier potassium current, the acetylcholine-activated potassium current and the small conductance calcium-activated potassium channel. Finally, we describe how heterogeneity and variability are being incorporated into AF-specific models, and how these approaches are yielding novel insights into the basic physiology of disease, as well as aiding identification of the important molecular players in the complex AF etiology.
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Affiliation(s)
- Márcia Vagos
- Computational Physiology Department, Simula Research Laboratory, Lysaker, Norway
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Ilsbeth G. M. van Herck
- Computational Physiology Department, Simula Research Laboratory, Lysaker, Norway
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Joakim Sundnes
- Computational Physiology Department, Simula Research Laboratory, Lysaker, Norway
- Center for Cardiological Innovation, Oslo, Norway
| | - Hermenegild J. Arevalo
- Computational Physiology Department, Simula Research Laboratory, Lysaker, Norway
- Center for Cardiological Innovation, Oslo, Norway
| | - Andrew G. Edwards
- Computational Physiology Department, Simula Research Laboratory, Lysaker, Norway
- Center for Cardiological Innovation, Oslo, Norway
| | - Jussi T. Koivumäki
- BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of Technology, Tampere, Finland
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
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7
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Srisomboon Y, Zaidman NA, Maniak PJ, Deachapunya C, O'Grady SM. P2Y receptor regulation of K2P channels that facilitate K + secretion by human mammary epithelial cells. Am J Physiol Cell Physiol 2018; 314:C627-C639. [PMID: 29365273 PMCID: PMC6008065 DOI: 10.1152/ajpcell.00342.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/17/2018] [Accepted: 01/17/2018] [Indexed: 02/07/2023]
Abstract
The objective of this study was to determine the molecular identity of ion channels involved in K+ secretion by the mammary epithelium and to examine their regulation by purinoceptor agonists. Apical membrane voltage-clamp experiments were performed on human mammary epithelial cells where the basolateral membrane was exposed to the pore-forming antibiotic amphotericin B dissolved in a solution with intracellular-like ionic composition. Addition of the Na+ channel inhibitor benzamil reduced the basal current, consistent with inhibition of Na+ uptake across the apical membrane, whereas the KCa3.1 channel blocker TRAM-34 produced an increase in current resulting from inhibition of basal K+ efflux. Treatment with two-pore potassium (K2P) channel blockers quinidine, bupivacaine and a selective TASK1/TASK3 inhibitor (PK-THPP) all produced concentration-dependent inhibition of apical K+ efflux. qRT-PCR experiments detected mRNA expression for nine K2P channel subtypes. Western blot analysis of biotinylated apical membranes and confocal immunocytochemistry revealed that at least five K2P subtypes (TWIK1, TREK1, TREK2, TASK1, and TASK3) are expressed in the apical membrane. Apical UTP also increased the current, but pretreatment with the PKC inhibitor GF109203X blocked the response. Similarly, direct activation of PKC with phorbol 12-myristate 13-acetate produced a similar increase in current as observed with UTP. These results support the conclusion that the basal level of K+ secretion involves constitutive activity of apical KCa3.1 channels and multiple K2P channel subtypes. Apical UTP evoked a transient increase in KCa3.1 channel activity, but over time caused persistent inhibition of K2P channel function leading to an overall decrease in K+ secretion.
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Affiliation(s)
| | - Nathan A Zaidman
- Departments of Animal Science, Integrative Biology, and Physiology, University of Minnesota , St. Paul, Minnesota
| | - Peter J Maniak
- Departments of Animal Science, Integrative Biology, and Physiology, University of Minnesota , St. Paul, Minnesota
| | | | - Scott M O'Grady
- Departments of Animal Science, Integrative Biology, and Physiology, University of Minnesota , St. Paul, Minnesota
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8
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Lambert M, Boet A, Rucker-Martin C, Mendes-Ferreira P, Capuano V, Hatem S, Adão R, Brás-Silva C, Hautefort A, Michel JB, Dorfmuller P, Fadel E, Kotsimbos T, Price L, Jourdon P, Montani D, Humbert M, Perros F, Antigny F. Loss of KCNK3 is a hallmark of RV hypertrophy/dysfunction associated with pulmonary hypertension. Cardiovasc Res 2018; 114:880-893. [DOI: 10.1093/cvr/cvy016] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 01/18/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mélanie Lambert
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Angèle Boet
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
- Réanimation des Cardiopathies Congénitales, Univ. Paris-Sud, Hôpital-Marie-Lannelongue, Le Plessis-Robinson, France
| | - Catherine Rucker-Martin
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Pedro Mendes-Ferreira
- Department of Surgery and Physiology, Faculty of Medicine, Cardiovascular Research Centre, University of Porto, 4200-319 Porto, Portugal
| | - Véronique Capuano
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Stéphane Hatem
- Département de Cardiologie, INSERM UMR_S1166, ICAN, Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière 75013, France
| | - Rui Adão
- Department of Surgery and Physiology, Faculty of Medicine, Cardiovascular Research Centre, University of Porto, 4200-319 Porto, Portugal
| | - Carmen Brás-Silva
- Department of Surgery and Physiology, Faculty of Medicine, Cardiovascular Research Centre, University of Porto, 4200-319 Porto, Portugal
| | - Aurélie Hautefort
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Jean-Baptiste Michel
- INSERM UMR_S1148, Paris7, Denis Diderot University, Xavier Bichat Hospital, 75018, Paris, France
| | - Peter Dorfmuller
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Elie Fadel
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
- Service de Chirurgie Thoracique, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France
| | - Tom Kotsimbos
- Department of Respiratory Medicine, Alfred Hospital, Monash University, Melbourne, VIC 3181, Australia
| | - Laura Price
- National Pulmonary Hypertension Service, Royal Brompton Hospital, London SW3 6NP, UK
| | - Philippe Jourdon
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - David Montani
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Marc Humbert
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Frédéric Perros
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
| | - Fabrice Antigny
- Univ. Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre 94270, France
- Assistance Publique Hôpitaux de Paris, Service de Pneumologie, Hôpital Bicêtre, Le Kremlin Bicêtre 94270, France
- Inserm UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson 92350, France
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Ravens U. Atrial-selective K + channel blockers: potential antiarrhythmic drugs in atrial fibrillation? Can J Physiol Pharmacol 2017; 95:1313-1318. [PMID: 28738160 DOI: 10.1139/cjpp-2017-0024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In the wake of demographic change in Western countries, atrial fibrillation has reached an epidemiological scale, yet current strategies for drug treatment of the arrhythmia lack sufficient efficacy and safety. In search of novel medications, atrial-selective drugs that specifically target atrial over other cardiac functions have been developed. Here, I will address drugs acting on potassium (K+) channels that are either predominantly expressed in atria or possess electrophysiological properties distinct in atria from ventricles. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting IKur, the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting IK,ACh, the Ca2+-activated K+ channels of small conductance (SK) conducting ISK, and the two-pore domain K+ (K2P) channels (tandem of P domains, weak inward-rectifying K+ channels (TWIK-1), TWIK-related acid-sensitive K+ channels (TASK-1 and TASK-3)) that are responsible for voltage-independent background currents ITWIK-1, ITASK-1, and ITASK-3. Direct drug effects on these channels are described and their putative value in treatment of atrial fibrillation is discussed. Although many potential drug targets have emerged in the process of unravelling details of the pathophysiological mechanisms responsible for atrial fibrillation, we do not know whether novel antiarrhythmic drugs will be more successful when modulating many targets or a single specific one. The answer to this riddle can only be solved in a clinical context.
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Affiliation(s)
- Ursula Ravens
- Institute of Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, University of Freiburg, Germany; Institute of Physiology, Medical Faculty Carl Gustav Carus, TU Dresden, Germany.,Institute of Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, University of Freiburg, Germany; Institute of Physiology, Medical Faculty Carl Gustav Carus, TU Dresden, Germany
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10
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Heijman J, Ghezelbash S, Wehrens XHT, Dobrev D. Serine/Threonine Phosphatases in Atrial Fibrillation. J Mol Cell Cardiol 2017; 103:110-120. [PMID: 28077320 DOI: 10.1016/j.yjmcc.2016.12.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 12/15/2016] [Accepted: 12/20/2016] [Indexed: 12/19/2022]
Abstract
Serine/threonine protein phosphatases control dephosphorylation of numerous cardiac proteins, including a variety of ion channels and calcium-handling proteins, thereby providing precise post-translational regulation of cardiac electrophysiology and function. Accordingly, dysfunction of this regulation can contribute to the initiation, maintenance and progression of cardiac arrhythmias. Atrial fibrillation (AF) is the most common heart rhythm disorder and is characterized by electrical, autonomic, calcium-handling, contractile, and structural remodeling, which include, among other things, changes in the phosphorylation status of a wide range of proteins. Here, we review AF-associated alterations in the phosphorylation of atrial ion channels, calcium-handling and contractile proteins, and their role in AF-pathophysiology. We highlight the mechanisms controlling the phosphorylation of these proteins and focus on the role of altered dephosphorylation via local type-1, type-2A and type-2B phosphatases (PP1, PP2A, and PP2B, also known as calcineurin, respectively). Finally, we discuss the challenges for phosphatase research, potential therapeutic significance of altered phosphatase-mediated protein dephosphorylation in AF, as well as future directions.
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Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Shokoufeh Ghezelbash
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Department of Molecular Physiology and Biophysics, Department of Medicine (Cardiology), Pediatrics, Baylor College of Medicine, Houston, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany.
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11
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Syeda F, Holmes AP, Yu TY, Tull S, Kuhlmann SM, Pavlovic D, Betney D, Riley G, Kucera JP, Jousset F, de Groot JR, Rohr S, Brown NA, Fabritz L, Kirchhof P. PITX2 Modulates Atrial Membrane Potential and the Antiarrhythmic Effects of Sodium-Channel Blockers. J Am Coll Cardiol 2016; 68:1881-1894. [PMID: 27765191 PMCID: PMC5075046 DOI: 10.1016/j.jacc.2016.07.766] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 07/05/2016] [Accepted: 07/20/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Antiarrhythmic drugs are widely used to treat patients with atrial fibrillation (AF), but the mechanisms conveying their variable effectiveness are not known. Recent data suggested that paired like homeodomain-2 transcription factor (PITX2) might play an important role in regulating gene expression and electrical function of the adult left atrium (LA). OBJECTIVES After determining LA PITX2 expression in AF patients requiring rhythm control therapy, the authors assessed the effects of Pitx2c on LA electrophysiology and the effect of antiarrhythmic drugs. METHODS LA PITX2 messenger ribonucleic acid (mRNA) levels were measured in 95 patients undergoing thoracoscopic AF ablation. The effects of flecainide, a sodium (Na+)-channel blocker, and d,l-sotalol, a potassium channel blocker, were studied in littermate mice with normal and reduced Pitx2c mRNA by electrophysiological study, optical mapping, and patch clamp studies. PITX2-dependent mechanisms of antiarrhythmic drug action were studied in human embryonic kidney (HEK) cells expressing human Na channels and by modeling human action potentials. RESULTS Flecainide 1 μmol/l was more effective in suppressing atrial arrhythmias in atria with reduced Pitx2c mRNA levels (Pitx2c+/-). Resting membrane potential was more depolarized in Pitx2c+/- atria, and TWIK-related acid-sensitive K+ channel 2 (TASK-2) gene and protein expression were decreased. This resulted in enhanced post-repolarization refractoriness and more effective Na-channel inhibition. Defined holding potentials eliminated differences in flecainide's effects between wild-type and Pitx2c+/- atrial cardiomyocytes. More positive holding potentials replicated the increased effectiveness of flecainide in blocking human Nav1.5 channels in HEK293 cells. Computer modeling reproduced an enhanced effectiveness of Na-channel block when resting membrane potential was slightly depolarized. CONCLUSIONS PITX2 mRNA modulates atrial resting membrane potential and thereby alters the effectiveness of Na-channel blockers. PITX2 and ion channels regulating the resting membrane potential may provide novel targets for antiarrhythmic drug development and companion therapeutics in AF.
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Affiliation(s)
- Fahima Syeda
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew P Holmes
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ting Y Yu
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Physical Sciences of Imaging in the Biomedical Sciences, School of Chemistry, University of Birmingham, Birmingham, United Kingdom
| | - Samantha Tull
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | | | - Davor Pavlovic
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Daniel Betney
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Genna Riley
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jan P Kucera
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Florian Jousset
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Joris R de Groot
- Heart Center, Department of Cardiology, Academisch Medisch Centrum, Amsterdam, the Netherlands
| | - Stephan Rohr
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Nigel A Brown
- St. George's Hospital Medical School, University of London, London, United Kingdom
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany; Atrial Fibrillation NETwork, Muenster, Germany; University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Paulus Kirchhof
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany; Atrial Fibrillation NETwork, Muenster, Germany; University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom; Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, United Kingdom.
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12
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Abstract
Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K+) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting IKur, the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting IK,ACh, the Ca2+-activated K+ channels of small conductance (SK) conducting ISK, and the two pore domain K+ (K2P) channels TWIK-1, TASK-1 and TASK-3 that are responsible for voltage-independent background currents ITWIK-1, ITASK-1, and ITASK-3. Here, we briefly review the characteristics of these K+ channels and their roles in atrial fibrillation. The antiarrhythmic potential of drugs targeting the described channels is discussed as well as their putative value in treatment of atrial fibrillation.
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Affiliation(s)
- Ursula Ravens
- Institute of Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany; Department of Cardiology and Angiology I, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany; Department of Physiology, Medical Faculty Carl-Gustav-Carus, TU Dresden, Dresden, Germany.
| | - Katja E Odening
- Institute of Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany; Department of Cardiology and Angiology I, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
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13
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Therapeutic targeting of two-pore-domain potassium (K(2P)) channels in the cardiovascular system. Clin Sci (Lond) 2016; 130:643-50. [PMID: 26993052 DOI: 10.1042/cs20150533] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The improvement of treatment strategies in cardiovascular medicine is an ongoing process that requires constant optimization. The ability of a therapeutic intervention to prevent cardiovascular pathology largely depends on its capacity to suppress the underlying mechanisms. Attenuation or reversal of disease-specific pathways has emerged as a promising paradigm, providing a mechanistic rationale for patient-tailored therapy. Two-pore-domain K(+) (K(2P)) channels conduct outward K(+) currents that stabilize the resting membrane potential and facilitate action potential repolarization. K(2P) expression in the cardiovascular system and polymodal K2P current regulation suggest functional significance and potential therapeutic roles of the channels. Recent work has focused primarily on K(2P)1.1 [tandem of pore domains in a weak inwardly rectifying K(+) channel (TWIK)-1], K(2P)2.1 [TWIK-related K(+) channel (TREK)-1], and K(2P)3.1 [TWIK-related acid-sensitive K(+) channel (TASK)-1] channels and their role in heart and vessels. K(2P) currents have been implicated in atrial and ventricular arrhythmogenesis and in setting the vascular tone. Furthermore, the association of genetic alterations in K(2P)3.1 channels with atrial fibrillation, cardiac conduction disorders and pulmonary arterial hypertension demonstrates the relevance of the channels in cardiovascular disease. The function, regulation and clinical significance of cardiovascular K(2P) channels are summarized in the present review, and therapeutic options are emphasized.
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14
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Hancox JC, James AF, Marrion NV, Zhang H, Thomas D. Novel ion channel targets in atrial fibrillation. Expert Opin Ther Targets 2016; 20:947-58. [DOI: 10.1517/14728222.2016.1159300] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, University Walk, Bristol, UK
| | - Andrew F. James
- School of Physiology, Pharmacology and Neuroscience, University Walk, Bristol, UK
| | - Neil V. Marrion
- School of Physiology, Pharmacology and Neuroscience, University Walk, Bristol, UK
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Dierk Thomas
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
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15
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16
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Xie C, Zhang Y, Tran TDN, Wang H, Li S, George EV, Zhuang H, Zhang P, Kandel A, Lai Y, Tang D, Reeves WH, Cheng H, Ding Y, Yang LJ. Irisin Controls Growth, Intracellular Ca2+ Signals, and Mitochondrial Thermogenesis in Cardiomyoblasts. PLoS One 2015; 10:e0136816. [PMID: 26305684 PMCID: PMC4549318 DOI: 10.1371/journal.pone.0136816] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/07/2015] [Indexed: 12/31/2022] Open
Abstract
Exercise offers short-term and long-term health benefits, including an increased metabolic rate and energy expenditure in myocardium. The newly-discovered exercise-induced myokine, irisin, stimulates conversion of white into brown adipocytes as well as increased mitochondrial biogenesis and energy expenditure. Remarkably, irisin is highly expressed in myocardium, but its physiological effects in the heart are unknown. The objective of this work is to investigate irisin’s potential multifaceted effects on cardiomyoblasts and myocardium. For this purpose, H9C2 cells were treated with recombinant irisin produced in yeast cells (r-irisin) and in HEK293 cells (hr-irisin) for examining its effects on cell proliferation by MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and on gene transcription profiles by qRT-PCR. R-irisin and hr-irisin both inhibited cell proliferation and activated genes related to cardiomyocyte metabolic function and differentiation, including myocardin, follistatin, smooth muscle actin, and nuclear respiratory factor-1. Signal transduction pathways affected by r-irisin in H9C2 cells and C57BL/6 mice were examined by detecting phosphorylation of PI3K-AKT, p38, ERK or STAT3. We also measured intracellular Ca2+ signaling and mitochondrial thermogenesis and energy expenditure in r-irisin-treated H9C2 cells. The results showed that r-irisin, in a certain concentration rage, could activate PI3K-AKT and intracellular Ca2+ signaling and increase cellular oxygen consumption in H9C2 cells. Our study also suggests the existence of irisin-specific receptor on the membrane of H9C2 cells. In conclusion, irisin in a certain concentration rage increased myocardial cell metabolism, inhibited cell proliferation and promoted cell differentiation. These effects might be mediated through PI3K-AKT and Ca2+ signaling, which are known to activate expression of exercise-related genes such as follistatin and myocardin. This work supports the value of exercise, which promotes irisin release.
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Affiliation(s)
- Chao Xie
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
| | - Yuan Zhang
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
- Center for Stem Cell & Regenerative Medicine, The Second Hospital of Shandong University, Jinan, 250012, P. R. China
| | - Tran D. N. Tran
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, United States of America
| | - Hai Wang
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
| | - Shiwu Li
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
| | - Eva Vertes George
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
| | - Haoyang Zhuang
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
| | - Peilan Zhang
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States of America
| | - Avi Kandel
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
| | - Yimu Lai
- Department of Cell Biology and Anatomy, University of South Carolina of Medicine, Columbia, SC, 29209, United States of America
| | - Dongqi Tang
- Center for Stem Cell & Regenerative Medicine, The Second Hospital of Shandong University, Jinan, 250012, P. R. China
| | - Westley H. Reeves
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
| | - Henrique Cheng
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, United States of America
| | - Yousong Ding
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States of America
- * E-mail: (L-JY); (YD)
| | - Li-Jun Yang
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America
- * E-mail: (L-JY); (YD)
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