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Eckardt L, Veltmann C. More than 30 years of Brugada syndrome: a critical appraisal of achievements and open issues. Herzschrittmacherther Elektrophysiol 2024; 35:9-18. [PMID: 38085327 DOI: 10.1007/s00399-023-00983-y] [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] [Accepted: 11/10/2023] [Indexed: 02/21/2024]
Abstract
Over the last three decades, what is referred to as Brugada syndrome (BrS) has developed from a clinical observation of initially a few cases of sudden cardiac death (SCD) in the absence of structural heart disease with ECG signs of "atypical right bundle brunch block" to a predominantly electrocardiographic, and to a lesser extent genetic, diagnosis. Today, BrS is diagnosed in patients without overt structural heart disease and a spontaneous Brugada type 1 ECG pattern regardless of symptoms. The diagnosis of BrS is less clear in those with an only transient or drug-induced type 1 Brugada pattern, but should be considered in the presence of an arrhythmic syncope, family history of BrS, or family history of sudden death. In addition to survived cardiac arrest, syncope is probably the single most decisive risk marker for future arrhythmias. For asymptomatic BrS, risk stratification remains challenging. General recommendations to lower the risk in BrS include avoidance of drugs/agents known to induce and/or increase right precordial ST-segment elevation, including treatment of fever with antipyretic drugs. Several ECG markers that have been associated with an increased risk of SCD have been incorporated into a recently published risk score for BrS. The aim of this article is to provide an overview of the status of risk stratification and to illustrate open issues und gaps in evidence in BrS.
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Affiliation(s)
- Lars Eckardt
- Department for Cardiology II: Electrophysiology, University Hospital Münster, Münster, Germany.
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Münster, Germany.
| | - Christian Veltmann
- Heart Center Bremen, Electrophysiology Bremen, Klinikum Links der Weser, Bremen, Germany
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2
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Korthals D, Eckardt L. The new European Society of Cardiology guideline for the management of cardiomyopathies: key messages for cardiac electrophysiologists. Herzschrittmacherther Elektrophysiol 2023; 34:311-323. [PMID: 37973628 PMCID: PMC10682323 DOI: 10.1007/s00399-023-00975-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 11/19/2023]
Abstract
Electrocardiographic findings and arrhythmias are common in cardiomyopathies. Both may be an early indication of a specific diagnosis or may occur due to myocardial fibrosis and/or reduced contractility. Brady- and tachyarrhythmias significantly contribute to increased morbidity and mortality in patients with cardiomyopathies. Antiarrhythmic therapy including risk stratification is often challenging and plays a major role for these patients. Thus, an "electrophysiological" perspective on guidelines on cardiomyopathies may be warranted. As the European Society of Cardiology (ESC) has recently published a new guideline for the management of cardiomyopathies, this overview aims to present key messages of these guidelines. Innovations include a new phenotype-based classification system with emphasis on a multimodal imaging approach for diagnosis and risk stratification. The guideline includes detailed chapters on dilated and hypertrophic cardiomyopathy and their phenocopies, arrhythmogenic right ventricular cardiomyopathy, and restrictive cardiomyopathy as well as syndromic and metabolic cardiomyopathies. Patient pathways guide clinicians from the initial presentation to diagnosis. The role of cardiovascular magnetic resonance imaging and genetic testing during diagnostic work-up is stressed. Concepts of rhythm and rate control for atrial fibrillation have led to new recommendations, and the role of defibrillator therapy in primary prevention is discussed in detail. Whilst providing general guidelines for management, the primary objective of the guideline is to ascertain the disease etiology and disease-specific, individualized management.
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Affiliation(s)
- Dennis Korthals
- Department of Cardiology II: Electrophysiology, University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany.
| | - Lars Eckardt
- Department of Cardiology II: Electrophysiology, University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
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3
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Steinberg C, Gaudreault N, Papadakis AI, Henry C, Champagne J, Philippon F, O’Hara G, Blier L, Plourde B, Nault I, Roy K, Sarrazin JF, Spatz A, Bossé Y. Leucocyte-derived micro-RNAs as candidate biomarkers in Brugada syndrome. Europace 2023; 25:euad145. [PMID: 37314195 PMCID: PMC10265963 DOI: 10.1093/europace/euad145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/02/2023] [Indexed: 06/15/2023] Open
Abstract
AIMS Risk stratification for sudden cardiac death in patients with Brugada syndrome remains a major challenge. Contemporary risk prediction models have only modest predictive value. The aim of this study was to assess the role of micro-RNAs from peripheral blood as candidate biomarkers in Brugada syndrome. METHODS AND RESULTS In this prospective study, Brugada patients and unaffected control individuals were enrolled for analysis of leucocyte-derived microRNAs (miRNAs) levels. Expression levels of 798 different circulating miRNAs were analysed on the NanoString® nCounter platform. All results were cross-validated by using a quantitative polymerase chain reaction. Micro-RNA expression levels of Brugada patients were compared with clinical data. A total of 21 definite Brugada patients (38% with a history of ventricular arrhythmia or cardiac arrest) and 30 unaffected control individuals were included in the study. Micro-RNA analysis showed a distinct expression profile in Brugada patients with 42 differentially expressed markers (38 up-regulated, 4 down-regulated miRNAs). The symptom status of Brugada patients was associated with a distinct miRNA signature. Micro-RNAs 145-5p and 585-3p were significantly up-regulated in symptomatic Brugada patients (P = 0.04). Incorporating miRNAs 145-5p and 585-3p into a multivariable model demonstrated significantly increased symptom prediction (area under the curve = 0.96; 95% confidence interval: 0.88-1.00). CONCLUSION Brugada patients display a distinct miRNA expression profile compared with unaffected control individuals. There is also evidence that certain miRNAs (miR-145-5p and miR-585-3p) are associated with the symptom status of Brugada patients. The results suggest the principal utility of leucocyte-derived miRNAs as prognostic biomarkers for Brugada syndrome.
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Affiliation(s)
- Christian Steinberg
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Nathalie Gaudreault
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Andreas I Papadakis
- Lady Davis Institute for Medical Research, Montreal Jewish Hospital, McGill University, Montreal, Canada
| | - Cyndi Henry
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Jean Champagne
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - François Philippon
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Gilles O’Hara
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Louis Blier
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Benoit Plourde
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Isabelle Nault
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Karine Roy
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Jean-François Sarrazin
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
| | - Alan Spatz
- Lady Davis Institute for Medical Research, Montreal Jewish Hospital, McGill University, Montreal, Canada
| | - Yohan Bossé
- Institut universitaire de cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Ste-Foy, Quebec City, Canada G1V 4G5
- Department of Molecular Medicine, Laval University, Quebec City, Canada
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Lu A, Gu R, Chu C, Xia Y, Wang J, Davis DR, Liang W. Inhibition of Wnt/β-catenin signaling upregulates Na v 1.5 channels in Brugada syndrome iPSC-derived cardiomyocytes. Physiol Rep 2023; 11:e15696. [PMID: 37226398 PMCID: PMC10209518 DOI: 10.14814/phy2.15696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 04/26/2023] [Accepted: 04/26/2023] [Indexed: 05/26/2023] Open
Abstract
The voltage-gated Nav 1.5 channels mediate the fast Na+ current (INa ) in cardiomyocytes initiating action potentials and cardiac contraction. Downregulation of INa , as occurs in Brugada syndrome (BrS), causes ventricular arrhythmias. The present study investigated whether the Wnt/β-catenin signaling regulates Nav 1.5 in human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). In healthy male and female iPSC-CMs, activation of Wnt/β-catenin signaling by CHIR-99021 reduced (p < 0.01) both Nav 1.5 protein and SCN5A mRNA. In iPSC-CMs from a BrS patient, both Nav 1.5 protein and peak INa were reduced compared to those in healthy iPSC-CMs. Treatment of BrS iPSC-CMs with Wnt-C59, a small-molecule Wnt inhibitor, led to a 2.1-fold increase in Nav 1.5 protein (p = 0.0005) but surprisingly did not affect SCN5A mRNA (p = 0.146). Similarly, inhibition of Wnt signaling using shRNA-mediated β-catenin knockdown in BrS iPSC-CMs led to a 4.0-fold increase in Nav 1.5, which was associated with a 4.9-fold increase in peak INa but only a 2.1-fold increase in SCN5A mRNA. The upregulation of Nav 1.5 by β-catenin knockdown was verified in iPSC-CMs from a second BrS patient. This study demonstrated that Wnt/β-catenin signaling inhibits Nav 1.5 expression in both male and female human iPSC-CMs, and inhibition of Wnt/β-catenin signaling upregulates Nav 1.5 in BrS iPSC-CMs through both transcriptional and posttranscriptional mechanisms.
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Affiliation(s)
- Aizhu Lu
- University of Ottawa Heart InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
| | - Ruonan Gu
- University of Ottawa Heart InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Department of Anesthesiology, Zhujiang HospitalSouthern Medical UniversityGuangzhouChina
| | - Cencen Chu
- University of Ottawa Heart InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
| | - Ying Xia
- University of Ottawa Heart InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
| | - Jerry Wang
- University of Ottawa Heart InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
| | - Darryl R. Davis
- University of Ottawa Heart InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
| | - Wenbin Liang
- University of Ottawa Heart InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
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Xing C, Bao L, Li W, Fan H. Progress on role of ion channels of cardiac fibroblasts in fibrosis. Front Physiol 2023; 14:1138306. [PMID: 36969589 PMCID: PMC10033868 DOI: 10.3389/fphys.2023.1138306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/27/2023] [Indexed: 03/29/2023] Open
Abstract
Cardiac fibrosis is defined as excessive deposition of extracellular matrix (ECM) in pathological conditions. Cardiac fibroblasts (CFs) activated by injury or inflammation differentiate into myofibroblasts (MFs) with secretory and contractile functions. In the fibrotic heart, MFs produce ECM which is composed mainly of collagen and is initially involved in maintaining tissue integrity. However, persistent fibrosis disrupts the coordination of excitatory contractile coupling, leading to systolic and diastolic dysfunction, and ultimately heart failure. Numerous studies have demonstrated that both voltage- and non-voltage-gated ion channels alter intracellular ion levels and cellular activity, contributing to myofibroblast proliferation, contraction, and secretory function. However, an effective treatment strategy for myocardial fibrosis has not been established. Therefore, this review describes the progress made in research related to transient receptor potential (TRP) channels, Piezo1, Ca2+ release-activated Ca2+ (CRAC) channels, voltage-gated Ca2+ channels (VGCCs), sodium channels, and potassium channels in myocardial fibroblasts with the aim of providing new ideas for treating myocardial fibrosis.
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6
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Yuan M, Guo Y, Xia H, Xu H, Deng H, Yuan L. Novel SCN5A and GPD1L Variants Identified in Two Unrelated Han-Chinese Patients With Clinically Suspected Brugada Syndrome. Front Cardiovasc Med 2021; 8:758903. [PMID: 34957250 PMCID: PMC8692717 DOI: 10.3389/fcvm.2021.758903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 10/29/2021] [Indexed: 12/25/2022] Open
Abstract
Brugada syndrome (BrS) is a complexly genetically patterned, rare, malignant, life-threatening arrhythmia disorder. It is autosomal dominant in most cases and characterized by identifiable electrocardiographic patterns, recurrent syncope, nocturnal agonal respiration, and other symptoms, including sudden cardiac death. Over the last 2 decades, a great number of variants have been identified in more than 36 pathogenic or susceptibility genes associated with BrS. The present study used the combined method of whole exome sequencing and Sanger sequencing to identify pathogenic variants in two unrelated Han-Chinese patients with clinically suspected BrS. Minigene splicing assay was used to evaluate the effects of the splicing variant. A novel heterozygous splicing variant c.2437-2A>C in the sodium voltage-gated channel alpha subunit 5 gene (SCN5A) and a novel heterozygous missense variant c.161A>T [p.(Asp54Val)] in the glycerol-3-phosphate dehydrogenase 1 like gene (GPD1L) were identified in these two patients with BrS-1 and possible BrS-2, respectively. Minigene splicing assay indicated the deletion of 15 and 141 nucleotides in exon 16, resulting in critical amino acid deletions. These findings expand the variant spectrum of SCN5A and GPD1L, which can be beneficial to genetic counseling and prenatal diagnosis.
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Affiliation(s)
- Meng Yuan
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yi Guo
- Department of Medical Information, School of Life Sciences, Central South University, Changsha, China
| | - Hong Xia
- Department of Emergency, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongbo Xu
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hao Deng
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China.,Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China.,Disease Genome Research Center, Central South University, Changsha, China
| | - Lamei Yuan
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China.,Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China.,Disease Genome Research Center, Central South University, Changsha, China
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7
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Two-Pore-Domain Potassium (K 2P-) Channels: Cardiac Expression Patterns and Disease-Specific Remodelling Processes. Cells 2021; 10:cells10112914. [PMID: 34831137 PMCID: PMC8616229 DOI: 10.3390/cells10112914] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 12/23/2022] Open
Abstract
Two-pore-domain potassium (K2P-) channels conduct outward K+ currents that maintain the resting membrane potential and modulate action potential repolarization. Members of the K2P channel family are widely expressed among different human cell types and organs where they were shown to regulate important physiological processes. Their functional activity is controlled by a broad variety of different stimuli, like pH level, temperature, and mechanical stress but also by the presence of lipids or pharmacological agents. In patients suffering from cardiovascular diseases, alterations in K2P-channel expression and function have been observed, suggesting functional significance and a potential therapeutic role of these ion channels. For example, upregulation of atrial specific K2P3.1 (TASK-1) currents in atrial fibrillation (AF) patients was shown to contribute to atrial action potential duration shortening, a key feature of AF-associated atrial electrical remodelling. Therefore, targeting K2P3.1 (TASK-1) channels might constitute an intriguing strategy for AF treatment. Further, mechanoactive K2P2.1 (TREK-1) currents have been implicated in the development of cardiac hypertrophy, cardiac fibrosis and heart failure. Cardiovascular expression of other K2P channels has been described, functional evidence in cardiac tissue however remains sparse. In the present review, expression, function, and regulation of cardiovascular K2P channels are summarized and compared among different species. Remodelling patterns, observed in disease models are discussed and compared to findings from clinical patients to assess the therapeutic potential of K2P channels.
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8
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Al Sayed ZR, Canac R, Cimarosti B, Bonnard C, Gourraud JB, Hamamy H, Kayserili H, Girardeau A, Jouni M, Jacob N, Gaignerie A, Chariau C, David L, Forest V, Marionneau C, Charpentier F, Loussouarn G, Lamirault G, Reversade B, Zibara K, Lemarchand P, Gaborit N. Human model of IRX5 mutations reveals key role for this transcription factor in ventricular conduction. Cardiovasc Res 2021; 117:2092-2107. [PMID: 32898233 DOI: 10.1093/cvr/cvaa259] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/15/2020] [Accepted: 08/28/2020] [Indexed: 01/02/2023] Open
Abstract
AIMS Several inherited arrhythmic diseases have been linked to single gene mutations in cardiac ion channels and interacting proteins. However, the mechanisms underlying most arrhythmias, are thought to involve altered regulation of the expression of multiple effectors. In this study, we aimed to examine the role of a transcription factor (TF) belonging to the Iroquois homeobox family, IRX5, in cardiac electrical function. METHODS AND RESULTS Using human cardiac tissues, transcriptomic correlative analyses between IRX5 and genes involved in cardiac electrical activity showed that in human ventricular compartment, IRX5 expression strongly correlated to the expression of major actors of cardiac conduction, including the sodium channel, Nav1.5, and Connexin 40 (Cx40). We then generated human-induced pluripotent stem cells (hiPSCs) derived from two Hamamy syndrome-affected patients carrying distinct homozygous loss-of-function mutations in IRX5 gene. Cardiomyocytes derived from these hiPSCs showed impaired cardiac gene expression programme, including misregulation in the control of Nav1.5 and Cx40 expression. In accordance with the prolonged QRS interval observed in Hamamy syndrome patients, a slower ventricular action potential depolarization due to sodium current reduction was observed on electrophysiological analyses performed on patient-derived cardiomyocytes, confirming the functional role of IRX5 in electrical conduction. Finally, a cardiac TF complex was newly identified, composed by IRX5 and GATA4, in which IRX5 potentiated GATA4-induction of SCN5A expression. CONCLUSION Altogether, this work unveils a key role for IRX5 in the regulation of human ventricular depolarization and cardiac electrical conduction, providing therefore new insights into our understanding of cardiac diseases.
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Affiliation(s)
- Zeina R Al Sayed
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Robin Canac
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Bastien Cimarosti
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Carine Bonnard
- Institute of Medical Biology, A*STAR, 8A Biomedical Grove, Singapore 138648, Singapore
| | - Jean-Baptiste Gourraud
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Hanan Hamamy
- Department of Genetic Medicine and Development, Geneva University, 1 rue Michel-Servet, Geneva 1211, Switzerland
| | - Hulya Kayserili
- Medical Genetics Department, Koç University School of Medicine(KUSOM), Rumelifeneri Yolu 34450, Istanbul, Turkey
| | - Aurore Girardeau
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Mariam Jouni
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Nicolas Jacob
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Anne Gaignerie
- Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, 8 Quai Moncousu, F-44000 Nantes, France
| | - Caroline Chariau
- Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, 8 Quai Moncousu, F-44000 Nantes, France
| | - Laurent David
- Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, 8 Quai Moncousu, F-44000 Nantes, France
- Université de Nantes, INSERM, CRTI, 30 Bd Jean Monnet, F-44093 Nantes, France
- ITUN, CHU Nantes, 30 Bd Jean Monnet, F-44093 Nantes, France
| | - Virginie Forest
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Céline Marionneau
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Flavien Charpentier
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Gildas Loussouarn
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Guillaume Lamirault
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Bruno Reversade
- Institute of Medical Biology, A*STAR, 8A Biomedical Grove, Singapore 138648, Singapore
- Medical Genetics Department, Koç University School of Medicine(KUSOM), Rumelifeneri Yolu 34450, Istanbul, Turkey
- Department of Paediatrics, National University of Singapore, 1E Kent Ridge Road, Singapore 119228, Singapore
- Institute of Molecular and Cellular Biology, A*STAR, 61 Biopolis Drive, Singapore 138673, Singapore
- Reproductive Biology Laboratory, Amsterdam UMC, Meibergdreef 9 1105, Amsterdam-Zuidoost, Netherlands
| | - Kazem Zibara
- ER045, Laboratory of stem cells, DSST, Biology department, Faculty of Sciences, Lebanese University, Rafic Hariri Campus - Hadath, Beirut 1700, Lebanon
| | - Patricia Lemarchand
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Nathalie Gaborit
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
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9
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Dolivo D, Rodrigues A, Sun L, Li Y, Hou C, Galiano R, Hong SJ, Mustoe T. The Na x (SCN7A) channel: an atypical regulator of tissue homeostasis and disease. Cell Mol Life Sci 2021; 78:5469-5488. [PMID: 34100980 PMCID: PMC11072345 DOI: 10.1007/s00018-021-03854-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/15/2021] [Accepted: 05/08/2021] [Indexed: 12/15/2022]
Abstract
Within an articulately characterized family of ion channels, the voltage-gated sodium channels, exists a black sheep, SCN7A (Nax). Nax, in contrast to members of its molecular family, has lost its voltage-gated character and instead rapidly evolved a new function as a concentration-dependent sensor of extracellular sodium ions and subsequent signal transducer. As it deviates fundamentally in function from the rest of its family, and since the bulk of the impressive body of literature elucidating the pathology and biochemistry of voltage-gated sodium channels has been performed in nervous tissue, reports of Nax expression and function have been sparse. Here, we investigate available reports surrounding expression and potential roles for Nax activity outside of nervous tissue. With these studies as justification, we propose that Nax likely acts as an early sensor that detects loss of tissue homeostasis through the pathological accumulation of extracellular sodium and/or through endothelin signaling. Sensation of homeostatic aberration via Nax then proceeds to induce pathological tissue phenotypes via promotion of pro-inflammatory and pro-fibrotic responses, induced through direct regulation of gene expression or through the generation of secondary signaling molecules, such as lactate, that can operate in an autocrine or paracrine fashion. We hope that our synthesis of much of the literature investigating this understudied protein will inspire more research into Nax not simply as a biochemical oddity, but also as a potential pathophysiological regulator and therapeutic target.
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Affiliation(s)
- David Dolivo
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Adrian Rodrigues
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Lauren Sun
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Yingxing Li
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Chun Hou
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
- Department of Plastic and Cosmetic Surgery, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Robert Galiano
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Seok Jong Hong
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA.
- , 300 E. Superior St., Chicago, IL, 60611, USA.
| | - Thomas Mustoe
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA.
- , 737 N. Michigan Ave., Chicago, IL, 60611, USA.
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10
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Herrera-Pérez S, Campos-Ríos A, Rueda-Ruzafa L, Lamas JA. Contribution of K2P Potassium Channels to Cardiac Physiology and Pathophysiology. Int J Mol Sci 2021; 22:ijms22126635. [PMID: 34205717 PMCID: PMC8234311 DOI: 10.3390/ijms22126635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/08/2021] [Accepted: 06/18/2021] [Indexed: 12/28/2022] Open
Abstract
Years before the first two-pore domain potassium channel (K2P) was cloned, certain ion channels had already been demonstrated to be present in the heart with characteristics and properties usually attributed to the TREK channels (a subfamily of K2P channels). K2P channels were later detected in cardiac tissue by RT-PCR, although the distribution of the different K2P subfamilies in the heart seems to depend on the species analyzed. In order to collect relevant information in this regard, we focus here on the TWIK, TASK and TREK cardiac channels, their putative roles in cardiac physiology and their implication in coronary pathologies. Most of the RNA expression data and electrophysiological recordings available to date support the presence of these different K2P subfamilies in distinct cardiac cells. Likewise, we show how these channels may be involved in certain pathologies, such as atrial fibrillation, long QT syndrome and Brugada syndrome.
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11
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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12
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Bogdanovic E, Potet F, Marszalec W, Iyer H, Galiano R, Hong SJ, Leung KP, Wasserstrom JA, George AL, Mustoe TA. The sodium channel Na X : Possible player in excitation-contraction coupling. IUBMB Life 2020; 72:601-606. [PMID: 32027092 DOI: 10.1002/iub.2247] [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: 10/15/2019] [Accepted: 01/18/2020] [Indexed: 11/10/2022]
Abstract
The sodium channel NaX (encoded by the SCN7A gene) was originally identified in the heart and skeletal muscle and is structurally similar to the other voltage-gated sodium channels but does not appear to be voltage gated. Although NaX is expressed at high levels in cardiac and skeletal muscle, little information exists on the function of NaX in these tissues. Transcriptional profiling of ion channels in the heart in a subset of patients with Brugada syndrome revealed an inverse relationship between the expression of NaX and NaV 1.5 suggesting that, in cardiac myocytes, the expression of these channels may be linked. We propose that NaX plays a role in excitation-contraction coupling based on our experimental observations. Here we show that in cardiac myocytes, NaX is expressed in a striated pattern on the sarcolemma in regions corresponding to the sarcomeric M-line. Knocking down NaX expression decreased NaV 1.5 mRNA and protein and reduced the inward sodium current (INa+ ) following cell depolarization. When the expression of NaV 1.5 was knocked down, ~85% of the INa+ was reduced consistent with the observations that NaV 1.5 is the main voltage-gated sodium channel in cardiac muscle and that NaX likely does not directly participate in mediating the INa+ following depolarization. Silencing NaV 1.5 expression led to significant upregulation of NaX mRNA. Similar to NaV 1.5, NaX protein levels were rapidly downregulated when the intracellular [Ca2+ ] was increased either by CaCl2 or caffeine. These data suggest that a relationship exists between NaX and NaV 1.5 and that NaX may play a role in excitation-contraction coupling.
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Affiliation(s)
- Elena Bogdanovic
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Franck Potet
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - William Marszalec
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Hari Iyer
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Robert Galiano
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Seok J Hong
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Kai P Leung
- Department of Dental and Maxillofacial Trauma, Institute of Surgical Research, Texas
| | | | - Alfred L George
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Thomas A Mustoe
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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13
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Guo F, Sun Y, Wang X, Wang H, Wang J, Gong T, Chen X, Zhang P, Su L, Fu G, Su J, Yang S, Lai R, Jiang C, Liang P. Patient-Specific and Gene-Corrected Induced Pluripotent Stem Cell-Derived Cardiomyocytes Elucidate Single-Cell Phenotype of Short QT Syndrome. Circ Res 2019; 124:66-78. [PMID: 30582453 DOI: 10.1161/circresaha.118.313518] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RATIONALE Short QT syndrome (SQT) is a rare but arrhythmogenic disorder featured by shortened ventricular repolarization and a propensity toward life-threatening ventricular arrhythmias and sudden cardiac death. OBJECTIVE This study aimed to investigate the single-cell mechanism of SQT using patient-specific and gene-corrected induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). METHODS AND RESULTS One SQT patient carrying missense mutation T618I in potassium voltage-gated channel subfamily H member 2 ( KCNH2) was recruited as well as 2 healthy control subjects in this study. Control and SQT patient-specific iPSCs were generated from skin fibroblasts using nonintegrated Sendai virus. The KCNH2 T618I mutation was corrected by genome editing in SQT iPSC lines to generate isogenic controls. All iPSCs were differentiated into iPSC-CMs using monolayer-based differentiation protocol. SQT iPSC-CMs exhibited abnormal action potential phenotype featured by shortened action potential duration and increased beat-beat interval variability, when compared with control and gene-corrected iPSC-CMs. Furthermore, SQT iPSC-CMs showed KCNH2 gain-of-function with increased rapid delayed rectifying potassium current (IKr) density and enhanced membrane expression. Gene expression profiling of iPSC-CMs exhibited a differential cardiac ion-channel gene expression profile of SQT. Moreover, QTc of SQT patient and action potential durations of SQT iPSC-CMs were both normalized by quinidine, indicating that quinidine is beneficial to KCNH2 T618I of SQT. Importantly, shortened action potential duration phenotype observed in SQT iPSC-CMs was effectively rescued by a short-peptide scorpion toxin BmKKx2 with a mechanism of targeting KCNH2. CONCLUSIONS We demonstrate that patient-specific and gene-corrected iPSC-CMs are able to recapitulate single-cell phenotype of SQT, which is caused by the gain-of-function mutation KCNH2 T618I. These findings will help elucidate the mechanisms underlying SQT and discover therapeutic drugs for treating the disease by using peptide toxins as lead compounds.
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Affiliation(s)
- Fengfeng Guo
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yaxun Sun
- Department of Cardiology (Y.S., C.J.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaochen Wang
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
| | - Hao Wang
- Department of Prenatal Diagnosis (Screening) Center, Hangzhou Women's Hospital (Hangzhou Maternity and Child Health Care Hospital), China (H.W.)
| | - Jue Wang
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
| | - Tingyu Gong
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xianzhen Chen
- Department of Dermatology and Venerology (X.C.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ping Zhang
- Department of Cardiology, Beijing Tsinghua Changgeng Hospital, China (P.Z.)
| | - Lan Su
- Cardiovascular Medicine Department, The First Affiliated Hospital of Wenzhou Medical University, China (L.S.)
| | - Guosheng Fu
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
| | - Jun Su
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.).,Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences (S.Y., L.R.), Kunming Institute of Zoology, China
| | - Shilong Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences (S.Y., L.R.), Kunming Institute of Zoology, China.,Key Laboratory of Bioactive Peptides of Yunnan Province (S.Y., L.R.), Kunming Institute of Zoology, China
| | - Ren Lai
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences (S.Y., L.R.), Kunming Institute of Zoology, China.,Key Laboratory of Bioactive Peptides of Yunnan Province (S.Y., L.R.), Kunming Institute of Zoology, China
| | - Chenyang Jiang
- Department of Cardiology (Y.S., C.J.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ping Liang
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
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14
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Heiss R, Wiesmueller M, Treutlein C, Seuss H, Uder M, May M, Wuest W. Cardiac T2 star mapping: standardized inline analysis of long and short axis at three identical 1.5 T MRI scanners. Int J Cardiovasc Imaging 2018; 35:695-702. [PMID: 30465128 DOI: 10.1007/s10554-018-1503-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/15/2018] [Indexed: 12/21/2022]
Abstract
T2 star mapping can be applied for in vivo cardiac iron quantification. Current recommendations of imaging acquisition, post-processing and interpretation of normal values are based on old scanner types and in house software packages. A standardized comparison of short (SAX) and long axis (LAX) segments using commercially available software packages and modern scanners is lacking. To provide a standardized comparison of T2 star time values in SAX and LAX and to investigate intersegmental, interregional and inter-level comparison and the interscanner reproducibility. 84 cardiac MRIs in 28 healthy volunteers were performed with three structurally identical 1.5 T MRI scanners. A commercially available software package for T2 star mapping with automatic in-line motion correction was used for analysis. Regions of interest were manually placed in each of the 16 myocardial segments according to the AHA model in three SAX and three LAX. A total of 2856 ROIs were drawn and 102 segments per volunteer were analysed. Interscanner reproducibility was high (91%) and the mean myocardial T2 star time value for all evaluated segments was 34 ± 5.7 ms. No significant difference was found between all measurements in SAX (35 ± 5.5 ms) and LAX (34 ± 5.8 ms). T2 star time values varied significantly between heart segments in the same axis and in 44% between corresponding SAX and LAX segments. T2 star time values in SAX and LAX have a high interscanner reproducibility but can vary significantly between heart segments in the same axis. Comparability between corresponding SAX and LAX segments is limited. To get representative results T2 star time values should be obtained in more than one heart segment and for follow-up studies identical segments should be used to avoid a systematic bias.
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Affiliation(s)
- Rafael Heiss
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3, 91054, Erlangen, Germany.
| | - Marco Wiesmueller
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Christoph Treutlein
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Hannes Seuss
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Michael Uder
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Matthias May
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Wolfgang Wuest
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3, 91054, Erlangen, Germany
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15
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Scridon A, Puertas RD, Manati W, Fouilloux-Meugnier E, Loizon E, Oréa V, Chapuis B, Julien C, Barrès C, Tabib A, Chevalier P. Age-dependent ventricular arrhythmias risk, structural and molecular remodeling in systemic arterial hypertension. Mech Ageing Dev 2017; 166:48-54. [DOI: 10.1016/j.mad.2017.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/01/2017] [Accepted: 07/08/2017] [Indexed: 12/01/2022]
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16
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Li Q, Zhao Y, Wu G, Chen S, Zhou Y, Li S, Zhou M, Fan Q, Pu J, Hong K, Cheng X, Kenneth Wang Q, Tu X. De Novo FGF12 (Fibroblast Growth Factor 12) Functional Variation Is Potentially Associated With Idiopathic Ventricular Tachycardia. J Am Heart Assoc 2017; 6:JAHA.117.006130. [PMID: 28775062 PMCID: PMC5586455 DOI: 10.1161/jaha.117.006130] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Background Idiopathic ventricular tachycardia (VT) is a type of cardiac arrhythmia occurring in structurally normal hearts. The heritability of idiopathic VT remains to be clarified, and numerous genetic factors responsible for development of idiopathic VT are as yet unclear. Variations in FGF12 (fibroblast growth factor 12), which is expressed in the human ventricle and modulates the cardiac Na+ channel NaV1.5, may play an important role in the genetic pathogenesis of VT. Methods and Results We tested the hypothesis that genetic variations in FGF12 are associated with VT in 2 independent Chinese cohorts and resequenced all the exons and exon–intron boundaries and the 5′ and 3′ untranslated regions of FGF12 in 320 unrelated participants with idiopathic VT. For population‐based case–control association studies, we chose 3 single‐nucleotide polymorphisms—rs1460922, rs4687326, and rs2686464—which included all the exons of FGF12. The results showed that the single‐nucleotide polymorphism rs1460922 in FGF12 was significantly associated with VT after adjusting for covariates of sex and age in 2 independent Chinese populations: adjusted P=0.015 (odds ratio: 1.54 [95% CI, 1.09–2.19]) in the discovery sample, adjusted P=0.018 (odds ratio: 1.64 [95% CI, 1.09–2.48]) in the replication sample, and adjusted P=2.52E‐04 (odds ratio: 1.59 [95% CI, 1.24–2.03]) in the combined sample. After resequencing all amino acid coding regions and untranslated regions of FGF12, 5 rare variations were identified. The result of western blotting revealed that a de novo functional variation, p.P211Q (1.84% of 163 patients with right ventricular outflow tract VT), could downregulate FGF12 expression significantly. Conclusions In this study, we observed that rs1460922 of FGF12 was significantly associated with VT and identified that a de novo variation of FGF12 may be an important genetic risk factor for the pathogenesis of VT.
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Affiliation(s)
- Qianqian Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China
| | - Yuanyuan Zhao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China.,Key Laboratory of Organ Transplantation, Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Ministry of Education and Ministry of Health, Wuhan, China
| | - Gang Wu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Shanshan Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China.,Key Laboratory for Molecular Diagnosis of Hubei Province, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yingchao Zhou
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China
| | - Sisi Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China
| | - Mengchen Zhou
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China
| | - Qian Fan
- The Laboratory of Cardiovascular Immunology, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Jielin Pu
- State Key Laboratory of Cardiovascular Disease, Physiology and Pathophysiology Laboratory, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kui Hong
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University and Jiangxi Key Laboratory of Molecular Medicine, Jiangxi, China
| | - Xiang Cheng
- The Laboratory of Cardiovascular Immunology, Institute of Cardiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Qing Kenneth Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China .,Department of Molecular Cardiology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Xin Tu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, China
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17
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The QUIDAM study: Hydroquinidine therapy for the management of Brugada syndrome patients at high arrhythmic risk. Heart Rhythm 2017; 14:1147-1154. [DOI: 10.1016/j.hrthm.2017.04.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Indexed: 12/19/2022]
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18
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Liang P, Sallam K, Wu H, Li Y, Itzhaki I, Garg P, Zhang Y, Vermglinchan V, Lan F, Gu M, Gong T, Zhuge Y, He C, Ebert AD, Sanchez-Freire V, Churko J, Hu S, Sharma A, Lam CK, Scheinman MM, Bers DM, Wu JC. Patient-Specific and Genome-Edited Induced Pluripotent Stem Cell-Derived Cardiomyocytes Elucidate Single-Cell Phenotype of Brugada Syndrome. J Am Coll Cardiol 2017; 68:2086-2096. [PMID: 27810048 DOI: 10.1016/j.jacc.2016.07.779] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 06/29/2016] [Accepted: 07/27/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND Brugada syndrome (BrS), a disorder associated with characteristic electrocardiogram precordial ST-segment elevation, predisposes afflicted patients to ventricular fibrillation and sudden cardiac death. Despite marked achievements in outlining the organ level pathophysiology of the disorder, the understanding of human cellular phenotype has lagged due to a lack of adequate human cellular models of the disorder. OBJECTIVES The objective of this study was to examine single cell mechanism of Brugada syndrome using induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). METHODS This study recruited 2 patients with type 1 BrS carrying 2 different sodium voltage-gated channel alpha subunit 5 variants as well as 2 healthy control subjects. We generated iPSCs from their skin fibroblasts by using integration-free Sendai virus. We used directed differentiation to create purified populations of iPSC-CMs. RESULTS BrS iPSC-CMs showed reductions in inward sodium current density and reduced maximal upstroke velocity of action potential compared with healthy control iPSC-CMs. Furthermore, BrS iPSC-CMs demonstrated increased burden of triggered activity, abnormal calcium (Ca2+) transients, and beating interval variation. Correction of the causative variant by genome editing was performed, and resultant iPSC-CMs showed resolution of triggered activity and abnormal Ca2+ transients. Gene expression profiling of iPSC-CMs showed clustering of BrS compared with control subjects. Furthermore, BrS iPSC-CM gene expression correlated with gene expression from BrS human cardiac tissue gene expression. CONCLUSIONS Patient-specific iPSC-CMs were able to recapitulate single-cell phenotype features of BrS, including blunted inward sodium current, increased triggered activity, and abnormal Ca2+ handling. This novel human cellular model creates future opportunities to further elucidate the cellular disease mechanism and identify novel therapeutic targets.
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Affiliation(s)
- Ping Liang
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California; The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Institute of Translational Medicine, Zhejiang University, Hangzhou, China.
| | - Karim Sallam
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Haodi Wu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Yingxin Li
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Ilanit Itzhaki
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Priyanka Garg
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Ying Zhang
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Vittavat Vermglinchan
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Feng Lan
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Mingxia Gu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Tingyu Gong
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California; The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Zhuge
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Chunjiang He
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Antje D Ebert
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Veronica Sanchez-Freire
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Jared Churko
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Shijun Hu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Arun Sharma
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Chi Keung Lam
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Melvin M Scheinman
- Department of Medicine, Division of Cardiology, University of California, San Francisco, California
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, California
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California.
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19
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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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Christensen AH, Chatelain FC, Huttner IG, Olesen MS, Soka M, Feliciangeli S, Horvat C, Santiago CF, Vandenberg JI, Schmitt N, Olesen SP, Lesage F, Fatkin D. The two-pore domain potassium channel, TWIK-1, has a role in the regulation of heart rate and atrial size. J Mol Cell Cardiol 2016; 97:24-35. [PMID: 27103460 DOI: 10.1016/j.yjmcc.2016.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/11/2016] [Accepted: 04/14/2016] [Indexed: 12/24/2022]
Abstract
The two-pore domain potassium (K(+)) channel TWIK-1 (or K2P1.1) contributes to background K(+) conductance in diverse cell types. TWIK-1, encoded by the KCNK1 gene, is present in the human heart with robust expression in the atria, however its physiological significance is unknown. To evaluate the cardiac effects of TWIK-1 deficiency, we studied zebrafish embryos after knockdown of the two KCNK1 orthologues, kcnk1a and kcnk1b. Knockdown of kcnk1a or kcnk1b individually caused bradycardia and atrial dilation (p<0.001 vs. controls), while ventricular stroke volume was preserved. Combined knockdown of both kcnk1a and kcnk1b resulted in a more severe phenotype, which was partially reversed by co-injection of wild-type human KCNK1 mRNA, but not by a dominant negative variant of human KCNK1 mRNA. To determine whether genetic variants in KCNK1 might cause atrial fibrillation (AF), we sequenced protein-coding regions in two independent cohorts of patients (373 subjects) and identified three non-synonymous variants, p.R171H, p.I198M and p.G236S, that were all located in highly conserved amino acid residues. In transfected mammalian cells, zebrafish and wild-type human TWIK-1 channels had a similar cellular distribution with predominant localization in the endosomal compartment. Two-electrode voltage-clamp experiments using Xenopus oocytes showed that both zebrafish and wild-type human TWIK-1 channels produced K(+) currents that are sensitive to external K(+) concentration as well as acidic pH. There were no effects of the three KCNK1 variants on cellular localization, current amplitude or reversal potential at pH7.4 or pH6. Our data indicate that TWIK-1 has a highly conserved role in cardiac function and is required for normal heart rate and atrial morphology. Despite the functional importance of TWIK-1 in the atrium, genetic variation in KCNK1 is not a common primary cause of human AF.
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Affiliation(s)
- Alex Hørby Christensen
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Franck C Chatelain
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, and Université de Nice Sophia-Antipolis, Sophia-Antipolis, Valbonne, France
| | - Inken G Huttner
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia; Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia
| | - Morten Salling Olesen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Magdalena Soka
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Sylvain Feliciangeli
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, and Université de Nice Sophia-Antipolis, Sophia-Antipolis, Valbonne, France
| | - Claire Horvat
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Celine F Santiago
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Jamie I Vandenberg
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia; Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia
| | - Nicole Schmitt
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Søren-Peter Olesen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Florian Lesage
- LabEx ICST, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, and Université de Nice Sophia-Antipolis, Sophia-Antipolis, Valbonne, France
| | - Diane Fatkin
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia; Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia; Cardiology Department, St Vincent's Hospital, Darlinghurst, New South Wales, Australia.
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21
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Taghli-Lamallem O, Plantié E, Jagla K. Drosophila in the Heart of Understanding Cardiac Diseases: Modeling Channelopathies and Cardiomyopathies in the Fruitfly. J Cardiovasc Dev Dis 2016; 3:jcdd3010007. [PMID: 29367558 PMCID: PMC5715700 DOI: 10.3390/jcdd3010007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 01/23/2016] [Accepted: 02/06/2016] [Indexed: 12/16/2022] Open
Abstract
Cardiovascular diseases and, among them, channelopathies and cardiomyopathies are a major cause of death worldwide. The molecular and genetic defects underlying these cardiac disorders are complex, leading to a large range of structural and functional heart phenotypes. Identification of molecular and functional mechanisms disrupted by mutations causing channelopathies and cardiomyopathies is essential to understanding the link between an altered gene and clinical phenotype. The development of animal models has been proven to be efficient for functional studies in channelopathies and cardiomyopathies. In particular, the Drosophila model has been largely applied for deciphering the molecular and cellular pathways affected in these inherited cardiac disorders and for identifying their genetic modifiers. Here we review the utility and the main contributions of the fruitfly models for the better understanding of channelopathies and cardiomyopathies. We also discuss the investigated pathological mechanisms and the discoveries of evolutionarily conserved pathways which reinforce the value of Drosophila in modeling human cardiac diseases.
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Affiliation(s)
- Ouarda Taghli-Lamallem
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France.
| | - Emilie Plantié
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France.
| | - Krzysztof Jagla
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France.
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22
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Frolov RV, Singh S. Celecoxib and ion channels: a story of unexpected discoveries. Eur J Pharmacol 2014; 730:61-71. [PMID: 24630832 DOI: 10.1016/j.ejphar.2014.02.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 01/28/2014] [Accepted: 02/18/2014] [Indexed: 10/25/2022]
Abstract
Celecoxib (Celebrex), a highly popular selective inhibitor of cyclooxygenase-2, can modulate ion channels and alter functioning of neurons and myocytes at clinically relevant concentrations independently of cyclooxygenase inhibition. In experimental systems varying from Drosophila to primary mammalian and human cell lines, celecoxib inhibits many voltage-activated Na(+), Ca(2+), and K(+) channels, including NaV1.5, L- and T-type Ca(2+) channels, KV1.5, KV2.1, KV4.3, KV7.1, KV11.1 (hERG), while stimulating other K(+) channels-KV7.2-5 and, possibly, KV11.1 (hERG) channels under certain conditions. In this review, we summarize the information currently available on the effects of celecoxib on ion channels, examine mechanistic aspects of drug action and the concomitant changes at the cellular and organ levels, and discuss these findings in the therapeutic context.
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Affiliation(s)
- Roman V Frolov
- Department of Physical Sciences, Division of Biophysics, University of Oulu, PO Box 3000, 90014 Oulun Yliopisto, Finland.
| | - Satpal Singh
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, NY 14214, USA
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23
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Age-dependent myocardial transcriptomic changes in the rat. Novel insights into atrial and ventricular arrhythmias pathogenesis. REV ROMANA MED LAB 2014. [DOI: 10.2478/rrlm-2014-0001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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24
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Paul M, Meyborg M, Boknik P, Gergs U, Gerss J, Schmitz W, Breithardt G, Wichter T, Neumann J. Autonomic dysfunction in patients with arrhythmogenic right ventricular cardiomyopathy: biochemical evidence of altered signaling pathways. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2013; 37:173-8. [PMID: 24025189 DOI: 10.1111/pace.12237] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 06/07/2013] [Accepted: 06/13/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden cardiac death especially in times of increased sympathetic tone, for example, during sports, which have been confirmed by nuclear imaging studies. However, the underlying biochemical pathways remain to be delineated. Therefore, we investigated the expression levels of proteins of the signaling cascade in patients with ARVC. METHODS During diagnostic work-up, right ventricular endomyocardial biopsies (EMBs) were sampled from 15 consecutive male ARVC patients (52 ± 14 years). Tissue levels of key proteins of the signaling cascade were analyzed. Results were compared to those obtained from EMBs of 10 patients with idiopathic right ventricular outflow-tract tachycardia (RVOT; 41 ± 14 years) and of five control subjects without identifiable structural heart disease (42 ± 13 years; P = ns). RESULTS Among the proteins analyzed, only tissue levels of norepinephrine (NE; P < 0.04) and cyclic adenosine-3´,5´-monophospate (cAMP; P < 0.01) were significantly lower in ARVC when compared to RVOT patients. When compared to controls, mean cAMP levels were lower in patients with ARVC but did not reach statistical significance. No differences in cAMP were observed between RVOT and controls. CONCLUSIONS The current findings confirm and expand the concept of adrenergic dysfunction in ARVC: the reduction of NE in ARVC could lead to an impaired stimulation of β-adrenoceptor subsequent signaling pathways with potential implication for cardiac fibrosis and arrhythmogenesis.
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Affiliation(s)
- Matthias Paul
- Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany
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25
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Frolov RV, Bagati A, Casino B, Singh S. Potassium channels in Drosophila: historical breakthroughs, significance, and perspectives. J Neurogenet 2013. [PMID: 23181728 DOI: 10.3109/01677063.2012.744990] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Drosophila has enabled important breakthroughs in K(+) channel research, including identification and fi rst cloning of a voltage-activated K(+) channel, Shaker, a founding member of the K(V)1 family. Drosophila has also helped in discovering other K(+) channels, such as Shab, Shaw, Shal, Eag, Sei, Elk, and also Slo, a Ca(2+) - and voltage-dependent K(+) channel. These findings have contributed significantly to our understanding of ion channels and their role in physiology. Drosophila continues to play an important role in ion channel studies, benefiting from an unparalleled arsenal of genetic tools and availability of tens of thousands of genetically modified strains. These tools allow deletion, expression, or misexpression of almost any gene in question with temporal and spatial control. The combination of these tools and resources with the use of forward genetic approach in Drosophila further enhances its strength as a model system. There are many areas in which Drosophila can further help our understanding of ion channels and their function. These include signaling pathways involved in regulating and modulating ion channels, basic information on channels and currents where very little is currently known, and the role of ion channels in physiology and pathology.
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Affiliation(s)
- Roman V Frolov
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214-3000, USA
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26
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Szuts V, Ménesi D, Varga-Orvos Z, Zvara Á, Houshmand N, Bitay M, Bogáts G, Virág L, Baczkó I, Szalontai B, Geramipoor A, Cotella D, Wettwer E, Ravens U, Deák F, Puskás LG, Papp JG, Kiss I, Varró A, Jost N. Altered expression of genes for Kir ion channels in dilated cardiomyopathy. Can J Physiol Pharmacol 2013; 91:648-56. [PMID: 23889090 DOI: 10.1139/cjpp-2012-0413] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dilated cardiomyopathy (DCM) is a multifactorial disease characterized by left ventricular dilation that is associated with systolic dysfunction and increased action potential duration. The Kir2.x K⁺ channels (encoded by KCNJ genes) regulate the inward rectifier current (IK1) contributing to the final repolarization in cardiac muscle. Here, we describe the transitions in the gene expression profiles of 4 KCNJ genes from healthy or dilated cardiomyopathic human hearts. In the healthy adult ventricles, KCNJ2, KCNJ12, and KCNJ4 (Kir2.1-2.3, respectively) genes were expressed at high levels, while expression of the KCNJ14 (Kir2.4) gene was low. In DCM ventricles, the levels of Kir2.1 and Kir2.3 were upregulated, but those of Kir2.2 channels were downregulated. Additionally, the expression of the DLG1 gene coding for the synapse-associated protein 97 (SAP97) anchoring molecule exhibited a 2-fold decline with increasing age in normal hearts, and it was robustly downregulated in young DCM patients. These adaptations could offer a new aspect for the explanation of the generally observed physiological and molecular alterations found in DCM.
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Affiliation(s)
- Viktoria Szuts
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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Bébarová M. Arrhythmogenesis in Brugada syndrome: impact and constrains of current concepts. Int J Cardiol 2013; 167:1760-71. [PMID: 23295036 DOI: 10.1016/j.ijcard.2012.12.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 11/15/2012] [Accepted: 12/06/2012] [Indexed: 01/13/2023]
Abstract
Brugada syndrome (BrS), an inherited arrhythmogenic disease first described in 1992, is characterized by ST segment elevations on the electrocardiogram in the right precordium and by a high occurrence of arrhythmias including the life-threatening ventricular tachycardia/fibrillation. Knowledge of the underlying mechanisms of formation of arrhythmogenic substrate in BrS is essential, namely for the risk stratification of BrS patients and their therapy which is still restrained almost exclusively to the implantation of cardioverter/defibrillator. In spite of many crucial findings in this field published within recent years, the final consistent view has not been established so far. Hence, BrS described 20 years ago remains an actual topic of both clinical and experimental studies. This review presents an overview of the current knowledge related to the pathogenesis of BrS arrhythmogenic substrate, namely of the genetic basis of BrS, functional consequences of mutations related to BrS, and arrhythmogenic mechanisms in BrS.
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Affiliation(s)
- Markéta Bébarová
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00 Brno, Bohunice, Czech Republic.
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28
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Abstract
Sudden cardiac death (SCD), a sudden pulseless condition due to cardiac arrhythmia, remains a major public health problem despite recent progress in the treatment and prevention of overall coronary heart disease. In this review, we examine the evidence for genetic susceptibility to SCD in order to provide biological insight into the pathogenesis of this devastating disease and to explore the potential for genetics to impact clinical management of SCD risk. Both candidate gene approaches and unbiased genome-wide scans have identified novel biological pathways contributing to SCD risk. Although risk stratification in the general population remains an elusive goal, several studies point to the potential utility of these common genetic variants in high-risk individuals. Finally, we highlight novel methodological approaches to deciphering the molecular mechanisms involved in arrhythmogenesis. Although further epidemiological and clinical applications research is needed, it is increasingly clear that genetic approaches are yielding important insights into SCD that may impact the public health burden imposed by SCD and its associated outcomes.
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Affiliation(s)
- Dan E Arking
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA.
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29
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Martin CA, Siedlecka U, Kemmerich K, Lawrence J, Cartledge J, Guzadhur L, Brice N, Grace AA, Schwiening C, Terracciano CM, Huang CLH. Reduced Na(+) and higher K(+) channel expression and function contribute to right ventricular origin of arrhythmias in Scn5a+/- mice. Open Biol 2012; 2:120072. [PMID: 22773948 PMCID: PMC3390792 DOI: 10.1098/rsob.120072] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 05/11/2012] [Indexed: 12/17/2022] Open
Abstract
Brugada syndrome (BrS) is associated with ventricular tachycardia originating particularly in the right ventricle (RV). We explore electrophysiological features predisposing to such arrhythmic tendency and their possible RV localization in a heterozygotic Scn5a+/- murine model. Na(v)1.5 mRNA and protein expression were lower in Scn5a+/- than wild-type (WT), with a further reduction in the RV compared with the left ventricle (LV). RVs showed higher expression levels of K(v)4.2, K(v)4.3 and KChIP2 in both Scn5a+/- and WT. Action potential upstroke velocity and maximum Na(+) current (I(Na)) density were correspondingly decreased in Scn5a+/-, with a further reduction in the RV. The voltage dependence of inactivation was shifted to more negative values in Scn5a+/-. These findings are predictive of a localized depolarization abnormality leading to slowed conduction. Persistent Na(+) current (I(pNa)) density was decreased in a similar pattern to I(Na). RV transient outward current (I(to)) density was greater than LV in both WT and Scn5a+/-, and had larger time constants of inactivation. These findings were also consistent with the observation that AP durations were smallest in the RV of Scn5a+/-, fulfilling predictions of an increased heterogeneity of repolarization as an additional possible electrophysiological mechanism for arrhythmogenesis in BrS.
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Affiliation(s)
- Claire A Martin
- Physiological Laboratory, University of Cambridge, Downing Site, Cambridge CB2 3EG, UK.
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Guzadhur L, Jiang W, Pearcey SM, Jeevaratnam K, Duehmke RM, Grace AA, Lei M, Huang CLH. The Age-dependence of atrial arrhythmogenicity in Scn5a+/−murine hearts reflects alterations in action potential propagation and recovery. Clin Exp Pharmacol Physiol 2012; 39:518-27. [DOI: 10.1111/j.1440-1681.2012.05706.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Laila Guzadhur
- Physiological Laboratory; University of Cambridge; Cambridge; UK
| | - Wenhui Jiang
- Medical College of Xi'an Jiaotong University; Xi'an; China
| | - Sarah M Pearcey
- Physiological Laboratory; University of Cambridge; Cambridge; UK
| | | | - Rudy M Duehmke
- Physiological Laboratory; University of Cambridge; Cambridge; UK
| | - Andrew A Grace
- Department of Biochemistry; University of Cambridge; Cambridge; UK
| | - Ming Lei
- Institute of Cardiovascular Sciences; University of Manchester; Manchester; UK
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Frolov RV, Ignatova II, Singh S. Inhibition of HERG potassium channels by celecoxib and its mechanism. PLoS One 2011; 6:e26344. [PMID: 22039467 PMCID: PMC3200315 DOI: 10.1371/journal.pone.0026344] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 09/25/2011] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Celecoxib (Celebrex), a widely prescribed selective inhibitor of cyclooxygenase-2, can modulate ion channels independently of cyclooxygenase inhibition. Clinically relevant concentrations of celecoxib can affect ionic currents and alter functioning of neurons and myocytes. In particular, inhibition of Kv2.1 channels by celecoxib leads to arrhythmic beating of Drosophila heart and of rat heart cells in culture. However, the spectrum of ion channels involved in human cardiac excitability differs from that in animal models, including mammalian models, making it difficult to evaluate the relevance of these observations to humans. Our aim was to examine the effects of celecoxib on hERG and other human channels critically involved in regulating human cardiac rhythm, and to explore the mechanisms of any observed effect on the hERG channels. METHODS AND RESULTS Celecoxib inhibited the hERG, SCN5A, KCNQ1 and KCNQ1/MinK channels expressed in HEK-293 cells with IC(50)s of 6.0 µM, 7.5 µM, 3.5 µM and 3.7 µM respectively, and the KCND3/KChiP2 channels expressed in CHO cells with an IC(50) of 10.6 µM. Analysis of celecoxib's effects on hERG channels suggested gating modification as the mechanism of drug action. CONCLUSIONS The above channels play a significant role in drug-induced long QT syndrome (LQTS) and short QT syndrome (SQTS). Regulatory guidelines require that all new drugs under development be tested for effects on the hERG channel prior to first administration in humans. Our observations raise the question of celecoxib's potential to induce cardiac arrhythmias or other channel related adverse effects, and make a case for examining such possibilities.
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Affiliation(s)
- Roman V. Frolov
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York, United States of America
- Division of Biophysics, Department of Physical Sciences, University of Oulu, Oulun Yliopisto, Finland
| | - Irina I. Ignatova
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York, United States of America
- Division of Biophysics, Department of Physical Sciences, University of Oulu, Oulun Yliopisto, Finland
| | - Satpal Singh
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York, United States of America
- * E-mail:
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Paul M, Meyborg M, Boknik P, Gergs U, Schmitz W, Breithardt G, Wichter T, Neumann J. Autonomic dysfunction in patients with Brugada syndrome: further biochemical evidence of altered signaling pathways. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2011; 34:1147-53. [PMID: 21605134 DOI: 10.1111/j.1540-8159.2011.03127.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND In patients with Brugada syndrome (BrS), life-threatening ventricular tachyarrhythmias predominantly occur during vagal stimulation at rest or during sleep. Previous imaging studies displayed an impaired autonomic function in BrS patients. However, it remains unclear whether these alterations primarily stem from a reduction of synaptic release of norepinephrine (NE) or an enhanced presynaptic reuptake. Both conditions could lead to reduced NE concentrations in the synaptic cleft. Therefore, we analyzed key components of the sympathoadrenergic signaling pathways in patients with BrS. METHODS AND RESULTS Endomyocardial biopsies were obtained from eight BrS patients (seven male; age 49 ± 15 years) and five controls (three male; age 43 ± 13 years; P = ns). The concentrations of NE, epinephrine (Epi), NE transport (NET) carrier protein, cyclic adenosine 5'monophosphate (cyclic adenosine monophosphate [cAMP]), inhibitory G-proteins (G(i1,2) α), troponin-I (TNI), and phosphorylated TNI were analyzed. Levels of NET, G(i1,2) α, TNI, Epi, and phosphorylated TNI were comparable between the groups. Compared to controls, patients with BrS showed reduced cAMP and NE concentrations. CONCLUSIONS The current findings expand the concept of adrenergic dysfunction in BrS: the reduction of NE in BrS could lead to an impaired stimulation of β-adrenoceptors resulting in a reduction of cAMP and alterations of the subsequent signaling pathway with potential implication for arrhythmogenesis.
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Affiliation(s)
- Matthias Paul
- Department of Cardiology and Angiology Institute of Pharmacology and Toxicology, University Hospital, Münster, Germany
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33
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Benito B, Guasch E, Rivard L, Nattel S. Clinical and mechanistic issues in early repolarization of normal variants and lethal arrhythmia syndromes. J Am Coll Cardiol 2010; 56:1177-86. [PMID: 20883924 DOI: 10.1016/j.jacc.2010.05.037] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 05/20/2010] [Accepted: 05/25/2010] [Indexed: 11/17/2022]
Abstract
Early repolarization, involving ST-segment elevation and, sometimes, prominent J waves at the QRS-ST junction, has been considered a normal electrocardiographic variant for over 60 years. A growing number of case reports and case-control studies indicate that in some instances, early repolarization patterns are associated with increased risk of idiopathic ventricular fibrillation. Epidemiological evidence indicates a dose effect for the risk of cardiac and sudden death with the extent of J-point elevation. This paper reviews present knowledge regarding the epidemiology, presentation, therapeutic response, and mechanisms characteristic of early repolarization. We highlight major unanswered questions relating to our limited ability to determine which individuals with this common electrocardiographic variant are at risk for sudden death, our incomplete understanding of underlying mechanisms, the inadequate information regarding genetic determinants and therapeutic responses, and the unclear relationship between early repolarization and other conditions involving accelerated repolarization and sudden arrhythmic death such as Brugada and short-QT syndromes. This review paper intends to inform the practicing physician about important clinical issues and to stimulate investigators to address the many unresolved questions in this rapidly evolving field.
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Affiliation(s)
- Begoña Benito
- Research Center and Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada
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34
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Es-Salah-Lamoureux Z, Steele DF, Fedida D. Research into the therapeutic roles of two-pore-domain potassium channels. Trends Pharmacol Sci 2010; 31:587-95. [PMID: 20951446 DOI: 10.1016/j.tips.2010.09.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 09/04/2010] [Accepted: 09/07/2010] [Indexed: 12/27/2022]
Abstract
The K(2P) potassium channels are responsible for the background conductance observed in several tissues. Their ubiquitous localization and thus their potential implications in diseases have led to increased research on these channels over the last few years. In this review, we outline different aspects of the research on K(2P) channels and highlight some of the latest discoveries in this area. We focus on research into K(2P) channels as potential therapeutic targets in ischemia/hypoxia, depression, memory disorders, pain, cardiovascular disease and disorders of the immune system. We address the challenge of developing novel pharmacological compounds to target these channels. We also discuss the regulation of expression of the K(2P) gene in health and disease, as well as the value of assessing the expression of K(2P) channels as potential biomarkers of disease.
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Affiliation(s)
- Zeineb Es-Salah-Lamoureux
- Department of Anesthesiology Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
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Dautova Y, Zhang Y, Grace AA, Huang CLH. Experimental Physiology -Research Paper: Atrial arrhythmogenic properties in wild-type andScn5a+/− murine hearts. Exp Physiol 2010; 95:994-1007. [DOI: 10.1113/expphysiol.2010.053868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wilde AAM, Postema PG, Di Diego JM, Viskin S, Morita H, Fish JM, Antzelevitch C. The pathophysiological mechanism underlying Brugada syndrome: depolarization versus repolarization. J Mol Cell Cardiol 2010; 49:543-53. [PMID: 20659475 DOI: 10.1016/j.yjmcc.2010.07.012] [Citation(s) in RCA: 253] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/13/2010] [Accepted: 07/19/2010] [Indexed: 12/29/2022]
Abstract
This Point/Counterpoint presents a scholarly debate of the mechanisms underlying the electrocardiographic and arrhythmic manifestations of Brugada syndrome (BrS), exploring in detail the available evidence in support of the repolarization vs. depolarization hypothesis.
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Affiliation(s)
- Arthur A M Wilde
- Department of Cardiology, Academic Medical Center Amsterdam, Amsterdam, The Netherlands
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Gender-related differences in ion-channel and transporter subunit expression in non-diseased human hearts. J Mol Cell Cardiol 2010; 49:639-46. [PMID: 20600101 DOI: 10.1016/j.yjmcc.2010.06.005] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 05/27/2010] [Accepted: 06/15/2010] [Indexed: 01/14/2023]
Abstract
Gender-related differences in ventricular electrophysiology are known to be important determinants of human arrhythmic risk, but the underlying molecular basis is poorly understood. The present work aims to provide the first detailed analysis of gender-related cardiac ion-channel gene-distribution, based on samples from non-diseased human hearts. By using a high-throughput quantitative approach, we investigated at a genome-scale the expression of 79 genes encoding ion-channel and transporter subunits in epicardial and endocardial tissue samples from non-diseased transplant donors (10 males, 10 females). Gender-related expression differences involved key genes implicated in conduction and repolarization. Female hearts showed reduced expression for a variety of K(+)-channel subunits with potentially important roles in cardiac repolarization, including HERG, minK, Kir2.3, Kv1.4, KChIP2, SUR2 and Kir6.2, as well as lower expression of connexin43 and phospholamban. In addition, they demonstrated an isoform switch in Na(+)/K(+)-ATPase, expressing more of the alpha1 and less of the alpha3 subunit than male hearts, along with increased expression of calmodulin-3. Iroquois transcription factors (IRX3, IRX5) were more strongly expressed in female than male epicardium, but the transmural gradient remained. Protein-expression paralleled transcript patterns for all subunits examined: HERG, minK, Kv1.4, KChIP2, IRX5, Nav1.5 and connexin43. Our results indicate that male and female human hearts have significant differences in ion-channel subunit composition, with female hearts showing decreased expression for a number of repolarizing ion-channels. These findings are important for understanding sex-related differences in the susceptibility to ventricular arrhythmias, particularly for conditions associated with repolarization abnormalities like Brugada and Long QT syndrome.
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Atrial arrhythmogenicity in aged Scn5a+/DeltaKPQ mice modeling long QT type 3 syndrome and its relationship to Na+ channel expression and cardiac conduction. Pflugers Arch 2010; 460:593-601. [PMID: 20552221 PMCID: PMC2903684 DOI: 10.1007/s00424-010-0851-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 05/05/2010] [Accepted: 05/26/2010] [Indexed: 12/19/2022]
Abstract
Recent studies have reported that human mutations in Nav1.5 predispose to early age onset atrial arrhythmia. The present experiments accordingly assess atrial arrhythmogenicity in aging Scn5a+/KPQ mice modeling long QT3 syndrome in relationship to cardiac Na(+) channel, Nav1.5, expression. Atrial electrophysiological properties in isolated Langendorff-perfused hearts from 3- and 12-month-old wild type (WT), and Scn5a+/KPQ mice were assessed using programmed electrical stimulation and their Nav1.5 expression assessed by Western blot. Cardiac conduction properties were assessed electrocardiographically in intact anesthetized animals. Monophasic action potential recordings demonstrated increased atrial arrhythmogenicity specifically in aged Scn5a+/DeltaKPQ hearts. These showed greater action potential duration/refractory period ratios but lower atrial Nav1.5 expression levels than aged WT mice. Atrial Nav1.5 levels were higher in young Scn5a+/DeltaKPQ than young WT. These levels increased with age in WT but not Scn5a+/DeltaKPQ. Both young and aged Scn5a+/DeltaKPQ mice showed lower heart rates and longer PR intervals than their WT counterparts. Young Scn5a+/DeltaKPQ mice showed longer QT and QTc intervals than young WT. Aged Scn5a+/DeltaKPQ showed longer QRS durations than aged WT. PR intervals were prolonged and QT intervals were shortened in young relative to aged WT. In contrast, ECG parameters were similar between young and aged Scn5a+/DeltaKPQ. Aged murine Scn5a+/DeltaKPQ hearts thus exhibit an increased atrial arrhythmogenicity. The differing Nav1.5 expression and electrocardiographic indicators of slowed cardiac conduction between Scn5a+/DeltaKPQ and WT, which show further variations associated with aging, may contribute toward atrial arrhythmia in aged Scn5a+/DeltaKPQ hearts.
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Nattel S, Frelin Y, Gaborit N, Louault C, Demolombe S. Ion-channel mRNA-expression profiling: Insights into cardiac remodeling and arrhythmic substrates. J Mol Cell Cardiol 2009; 48:96-105. [PMID: 19631654 DOI: 10.1016/j.yjmcc.2009.07.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 06/17/2009] [Accepted: 07/09/2009] [Indexed: 11/20/2022]
Abstract
Membrane ion channels and transporters are key determinants of cardiac electrical function. Their expression is affected by cardiac region, hemodynamic properties, heart-rate changes, neurohormones and cardiac disease. One of the important determinants of ion-channel function is the level of ion-channel subunit mRNA expression, which governs the production of ion-channel proteins that traffic to the cell-membrane to form functional ion-channels. Ion-channel mRNA-expression profiling can be performed with cDNA microarrays or high-throughput reverse transcription/polymerase chain reaction (PCR) methods. Expression profiling has been applied to evaluate the dependence of ion-channel expression on cardiac region, revealing the molecular basis of regionally-controlled electrical properties as well as the molecular determinants of specialized electrical functions like pacemaking activity. Ion-channel remodeling occurs with cardiac diseases like heart failure, congenital repolarization abnormalities, and atrial fibrillation, and expression profiling has provided insights into the mechanisms by which these conditions affect cardiac electrical stability. Expression profiling has also shown how hormonal changes, antiarrhythmic drugs, cardiac development and altered heart rate affect ion-channel expression patterns to modify cardiac electrical function and sometimes to produce cardiac rhythm disturbances. This article reviews the information obtained to date with the application of cardiac ion-channel expression profiling. With increasing availability and efficiency of high-throughput PCR methods for ion-channel subunit mRNA-expression characterization, it is likely that the application of ion-channel expression profiling will increase and that it will provide important new insights into the determinants of cardiac electrical function in both physiological and pathological situations.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute, Université de Montréal, Canada.
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