1
|
Mushtaq I, Hsieh TH, Chen YC, Kao YH, Chen YJ. MicroRNA-452-5p regulates fibrogenesis via targeting TGF-β/SMAD4 axis in SCN5A-knockdown human cardiac fibroblasts. iScience 2024; 27:110084. [PMID: 38883840 PMCID: PMC11179076 DOI: 10.1016/j.isci.2024.110084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/20/2024] [Accepted: 05/20/2024] [Indexed: 06/18/2024] Open
Abstract
The mutated SCN5A gene encoding defective Nav1.5 protein causes arrhythmic ailments and is associated with enhanced cardiac fibrosis. This study investigated whether SCN5A mutation directly affects cardiac fibroblasts and explored how defective SCN5A relates to cardiac fibrosis. SCN5A knockdown (SCN5AKD) human cardiac fibroblasts (HCF) had higher collagen, α-SMA, and fibronectin expressions. Micro-RNA deep sequencing and qPCR analysis revealed the downregulation of miR-452-5p and bioinformatic analysis divulged maladaptive upregulation of transforming growth factor β (TGF-β) signaling in SCN5AKD HCF. Luciferase reporter assays validated miR-452-5p targets SMAD4 in SCN5AKD HCF. Moreover, miR-452-5p mimic transfection in SCN5AKD HCF or AAV9-mediated miR-452-5p delivery in isoproterenol-induced heart failure (HF) rats, resulted in the attenuation of TGF-β signaling and fibrogenesis. The exogenous miR-452-5p significantly improved the poor cardiac function in HF rats. In conclusion, miR-452-5p regulates cardiac fibrosis progression by targeting the TGF-β/SMAD4 axis under the loss of the SCN5A gene.
Collapse
Affiliation(s)
- Iqra Mushtaq
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tsung-Han Hsieh
- Joint Biobank, Office of Human Research, Taipei Medical University, Taipei, Taiwan
| | - Yao-Chang Chen
- Department of Biomedical Engineering, National Defense Medical Center, Taipei, Taiwan
| | - Yu-Hsun Kao
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Medical Education and Research, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yi-Jen Chen
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Cardiovascular Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Taipei Heart Institute, Taipei Medical University, Taipei, Taiwan
| |
Collapse
|
2
|
Ferrand MC, Giordano G, Mougenot N, Laporte PL, Vignier N, Leclerc A, Algalarrondo V, Extramiana F, Charpentier F, Neyroud N. Intracardiac electrophysiology to characterize susceptibility to ventricular arrhythmias in murine models. Front Physiol 2024; 15:1326663. [PMID: 38322613 PMCID: PMC10846502 DOI: 10.3389/fphys.2024.1326663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/08/2024] [Indexed: 02/08/2024] Open
Abstract
Introduction: Sudden cardiac death (SCD) and ventricular fibrillation are rare but severe complications of many cardiovascular diseases and represent a major health issue worldwide. Although the primary causes are often acute or chronic coronary diseases, genetic conditions, such as inherited channelopathies or non-ischemic cardiomyopathies are leading causes of SCD among the young. However, relevant experimental models to study the underlying mechanisms of arrhythmias and develop new therapies are still needed. The number of genetically engineered mouse models with cardiac phenotype is growing, making electrophysiological studies in mice essential tools to study arrhythmogenicity and arrhythmia mechanisms and to test novel treatments. Recently, intracardiac catheterization via the jugular vein was described to induce and record ventricular arrhythmias in living anesthetized mice. Several strategies have been reported, developed in healthy wild-type animals and based on aggressive right ventricular stimulation. Methods: Here, we report a protocol based on programmed electrical stimulation (PES) performed in clinical practice in patients with cardiac rhythm disorders, adapted to two transgenic mice models of arrhythmia - Brugada syndrome and cardiolaminopathy. Results: We show that this progressive protocol, based on a limited number of right ventricular extrastimuli, enables to reveal different rhythmic phenotypes between control and diseased mice. In this study, we provide detailed information on PES in mice, including catheter positioning, stimulation protocols, intracardiac and surface ECG interpretation and we reveal a higher susceptibility of two mouse lines to experience triggered ventricular arrhythmias, when compared to control mice. Discussion: Overall, this technique allows to characterize arrhythmias and provides results in phenotyping 2 arrhythmogenic-disease murine models.
Collapse
Affiliation(s)
- Marine C. Ferrand
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France
| | - Gauthier Giordano
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France
- Competence Center for Hereditary or Rare Heart Diseases, Centre Hospitalier Régional Universitaire de Nancy, Vandœuvre-lès-Nancy, France
| | | | - Pierre-Léo Laporte
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France
- Reference Center for Inherited Arrhythmic Syndromes, Hôpital Bichat, APHP, Université de Paris Cité, Paris, France
| | - Nicolas Vignier
- Sorbonne Université, Inserm, UMRS-974, Center of Research in Myology, Institute of Myology, Paris, France
| | - Arnaud Leclerc
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France
| | - Vincent Algalarrondo
- Reference Center for Inherited Arrhythmic Syndromes, Hôpital Bichat, APHP, Université de Paris Cité, Paris, France
| | - Fabrice Extramiana
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France
- Reference Center for Inherited Arrhythmic Syndromes, Hôpital Bichat, APHP, Université de Paris Cité, Paris, France
| | | | - Nathalie Neyroud
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France
| |
Collapse
|
3
|
Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
Collapse
Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
| |
Collapse
|
4
|
Moras E, Gandhi K, Narasimhan B, Brugada R, Brugada J, Brugada P, Krittanawong C. Genetic and Molecular Mechanisms in Brugada Syndrome. Cells 2023; 12:1791. [PMID: 37443825 PMCID: PMC10340412 DOI: 10.3390/cells12131791] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Brugada syndrome is a rare hereditary arrhythmia disorder characterized by a distinctive electrocardiogram pattern and an elevated risk of ventricular arrhythmias and sudden cardiac death in young adults. Despite recent advances, it remains a complex condition, encompassing mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management. The underlying electrophysiological mechanism of Brugada syndrome requires further investigation, with current theories focusing on abnormalities in repolarization, depolarization, and current-load match. The genetic basis of the syndrome is strong, with mutations found in genes encoding subunits of cardiac sodium, potassium, and calcium channels, as well as genes involved in channel trafficking and regulation. While the initial discovery of mutations in the SCN5A gene provided valuable insights, Brugada syndrome is now recognized as a multifactorial disease influenced by several loci and environmental factors, challenging the traditional autosomal dominant inheritance model. This comprehensive review aims to provide a current understanding of Brugada syndrome, focusing on its pathophysiology, genetic mechanisms, and novel models of risk stratification. Advancements in these areas hold the potential to facilitate earlier diagnosis, improve risk assessments, and enable more targeted therapeutic interventions.
Collapse
Affiliation(s)
- Errol Moras
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kruti Gandhi
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Bharat Narasimhan
- Debakey Cardiovascular Institute, Houston Methodist Hospital, Houston, TX 77030, USA
| | - Ramon Brugada
- Cardiology, Cardiac Genetics Clinical Unit, Hospital Universitari Josep Trueta, Hospital Santa Caterina, 17007 Girona, Spain
- Cardiovascular Genetics Center and Clinical Diagnostic Laboratory, Institut d’Investigació Biomèdica Girona-IdIBGi, 17190 Salt, Spain
| | - Josep Brugada
- Cardiovascular Institute, Hospital Clínic, 08036 Barcelona, Spain
- Pediatric Arrhythmia Unit, Hospital Sant Joan de Déu, 08950 Barcelona, Spain
- Department of Medicine, University of Barcelona, 08036 Barcelona, Spain
| | - Pedro Brugada
- Cardiovascular Division, Free University of Brussels (UZ Brussel) VUB, B-1050 Brussels, Belgium
- Medical Centre Prof. Brugada, B-9300 Aalst, Belgium
- Arrhythmia Unit, Helicopteros Sanitarios Hospital (HSH), Puerto Banús, 29603 Marbella, Spain
| | - Chayakrit Krittanawong
- Cardiology Division, NYU Langone Health and NYU School of Medicine, New York, NY 10016, USA
| |
Collapse
|
5
|
Popa IP, Șerban DN, Mărănducă MA, Șerban IL, Tamba BI, Tudorancea I. Brugada Syndrome: From Molecular Mechanisms and Genetics to Risk Stratification. Int J Mol Sci 2023; 24:ijms24043328. [PMID: 36834739 PMCID: PMC9967917 DOI: 10.3390/ijms24043328] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/13/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Brugada syndrome (BrS) is a rare hereditary arrhythmia disorder, with a distinctive ECG pattern, correlated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD) in young adults. BrS is a complex entity in terms of mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management. The main electrophysiological mechanism of BrS requires further research, with prevailing theories centered on aberrant repolarization, depolarization, and current-load match. Computational modelling, pre-clinical, and clinical research show that BrS molecular anomalies result in excitation wavelength (k) modifications, which eventually increase the risk of arrhythmia. Although a mutation in the SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5) gene was first reported almost two decades ago, BrS is still currently regarded as a Mendelian condition inherited in an autosomal dominant manner with incomplete penetrance, despite the recent developments in the field of genetics and the latest hypothesis of additional inheritance pathways proposing a more complex mode of inheritance. In spite of the extensive use of the next-generation sequencing (NGS) technique with high coverage, genetics remains unexplained in a number of clinically confirmed cases. Except for the SCN5A which encodes the cardiac sodium channel NaV1.5, susceptibility genes remain mostly unidentified. The predominance of cardiac transcription factor loci suggests that transcriptional regulation is essential to the Brugada syndrome's pathogenesis. It appears that BrS is a multifactorial disease, which is influenced by several loci, each of which is affected by the environment. The primary challenge in individuals with a BrS type 1 ECG is to identify those who are at risk for sudden death, researchers propose the use of a multiparametric clinical and instrumental strategy for risk stratification. The aim of this review is to summarize the latest findings addressing the genetic architecture of BrS and to provide novel perspectives into its molecular underpinnings and novel models of risk stratification.
Collapse
Affiliation(s)
- Irene Paula Popa
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
| | - Dragomir N. Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Minela Aida Mărănducă
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Ionela Lăcrămioara Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Bogdan Ionel Tamba
- Department of Pharmacology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
- Correspondence:
| | - Ionuț Tudorancea
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| |
Collapse
|
6
|
Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
Collapse
Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| |
Collapse
|
7
|
Yu G, Chakrabarti S, Tischenko M, Chen AL, Wang Z, Cho H, French BA, Naga Prasad SV, Chen Q, Wang QK. Gene therapy targeting protein trafficking regulator MOG1 in mouse models of Brugada syndrome, arrhythmias, and mild cardiomyopathy. Sci Transl Med 2022; 14:eabf3136. [PMID: 35675436 DOI: 10.1126/scitranslmed.abf3136] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Brugada syndrome (BrS) is a fatal arrhythmia that causes an estimated 4% of all sudden death in high-incidence areas. SCN5A encodes cardiac sodium channel NaV1.5 and causes 25 to 30% of BrS cases. Here, we report generation of a knock-in (KI) mouse model of BrS (Scn5aG1746R/+). Heterozygous KI mice recapitulated some of the clinical features of BrS, including an ST segment abnormality (a prominent J wave) on electrocardiograms and development of spontaneous ventricular tachyarrhythmias (VTs), seizures, and sudden death. VTs were caused by shortened cardiac action potential duration and late phase 3 early afterdepolarizations associated with reduced sodium current density (INa) and increased Kcnd3 and Cacna1c expression. We developed a gene therapy using adeno-associated virus serotype 9 (AAV9) vector-mediated MOG1 delivery for up-regulation of MOG1, a chaperone that binds to NaV1.5 and traffics it to the cell surface. MOG1 was chosen for gene therapy because the large size of the SCN5A coding sequence (6048 base pairs) exceeds the packaging capacity of AAV vectors. AAV9-MOG1 gene therapy increased cell surface expression of NaV1.5 and ventricular INa, reversed up-regulation of Kcnd3 and Cacna1c expression, normalized cardiac action potential abnormalities, abolished J waves, and blocked VT in Scn5aG1746R/+ mice. Gene therapy also rescued the phenotypes of cardiac arrhythmias and contractile dysfunction in heterozygous humanized KI mice with SCN5A mutation p.D1275N. Using a small chaperone protein may have broad implications for targeting disease-causing genes exceeding the size capacity of AAV vectors.
Collapse
Affiliation(s)
- Gang Yu
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Susmita Chakrabarti
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Miroslava Tischenko
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Ai-Lan Chen
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Cardiology, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 511436, P. R. China
| | - Zhijie Wang
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Hyosuk Cho
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Brent A French
- Department of Biomedical Engineering, University of Virginia Health System, Charlottesville, VA 22903, USA
| | - Sathyamangla V Naga Prasad
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Qiuyun Chen
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Qing K Wang
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| |
Collapse
|
8
|
Absolute Quantification of Nav1.5 Expression by Targeted Mass Spectrometry. Int J Mol Sci 2022; 23:ijms23084177. [PMID: 35456996 PMCID: PMC9028338 DOI: 10.3390/ijms23084177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 11/20/2022] Open
Abstract
Nav1.5 is the pore forming α-subunit of the cardiac voltage-gated sodium channel that initiates cardiac action potential and regulates the human heartbeat. A normal level of Nav1.5 is crucial to cardiac function and health. Over- or under-expression of Nav1.5 can cause various cardiac diseases ranging from short PR intervals to Brugada syndromes. An assay that can directly quantify the protein amount in biological samples would be a priori to accurately diagnose and treat Nav1.5-associated cardiac diseases. Due to its large size (>200 KD), multipass transmembrane domains (24 transmembrane passes), and heavy modifications, Nav1.5 poses special quantitation challenges. To date, only the relative quantities of this protein have been measured in biological samples. Here, we describe the first targeted and mass spectrometry (MS)-based quantitative assay that can provide the copy numbers of Nav1.5 in cells with a well-defined lower limit of quantification (LLOQ) and precision. Applying the developed assay, we successfully quantified transiently expressed Nav1.5 in as few as 1.5 million Chinese hamster ovary (CHO) cells. The obtained quantity was 3 ± 2 fmol on the column and 3 ± 2 × 104 copies/cell. To our knowledge, this is the first absolute quantity of Nav1.5 measured in a biological sample.
Collapse
|
9
|
Li Y, Lang S, Akin I, Zhou X, El-Battrawy I. Brugada Syndrome: Different Experimental Models and the Role of Human Cardiomyocytes From Induced Pluripotent Stem Cells. J Am Heart Assoc 2022; 11:e024410. [PMID: 35322667 PMCID: PMC9075459 DOI: 10.1161/jaha.121.024410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Brugada syndrome (BrS) is an inherited and rare cardiac arrhythmogenic disease associated with an increased risk of ventricular fibrillation and sudden cardiac death. Different genes have been linked to BrS. The majority of mutations are located in the SCN5A gene, and the typical abnormal ECG is an elevation of the ST segment in the right precordial leads V1 to V3. The pathophysiological mechanisms of BrS were studied in different models, including animal models, heterologous expression systems, and human-induced pluripotent stem cell-derived cardiomyocyte models. Currently, only a few BrS studies have used human-induced pluripotent stem cell-derived cardiomyocytes, most of which have focused on genotype-phenotype correlations and drug screening. The combination of new technologies, such as clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 (CRISPR associated protein 9)-mediated genome editing and 3-dimensional engineered heart tissues, has provided novel insights into the pathophysiological mechanisms of the disease and could offer opportunities to improve the diagnosis and treatment of patients with BrS. This review aimed to compare different models of BrS for a better understanding of the roles of human-induced pluripotent stem cell-derived cardiomyocytes in current BrS research and personalized medicine at a later stage.
Collapse
Affiliation(s)
- Yingrui Li
- First Department of Medicine Medical Faculty Mannheim University Medical Centre Mannheim (UMM)University of Heidelberg Mannheim Germany
| | - Siegfried Lang
- First Department of Medicine Medical Faculty Mannheim University Medical Centre Mannheim (UMM)University of Heidelberg Mannheim Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim Mannheim Germany
| | - Ibrahim Akin
- First Department of Medicine Medical Faculty Mannheim University Medical Centre Mannheim (UMM)University of Heidelberg Mannheim Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim Mannheim Germany
| | - Xiaobo Zhou
- First Department of Medicine Medical Faculty Mannheim University Medical Centre Mannheim (UMM)University of Heidelberg Mannheim Germany.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province Institute of Cardiovascular Research Southwest Medical University Luzhou Sichuan China.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim Mannheim Germany
| | - Ibrahim El-Battrawy
- First Department of Medicine Medical Faculty Mannheim University Medical Centre Mannheim (UMM)University of Heidelberg Mannheim Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim Mannheim Germany.,Department of Cardiology and Angiology Bergmannsheil Bochum Medical Clinic II Ruhr University Bochum Germany
| |
Collapse
|
10
|
Iop L, Iliceto S, Civieri G, Tona F. Inherited and Acquired Rhythm Disturbances in Sick Sinus Syndrome, Brugada Syndrome, and Atrial Fibrillation: Lessons from Preclinical Modeling. Cells 2021; 10:3175. [PMID: 34831398 PMCID: PMC8623957 DOI: 10.3390/cells10113175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/03/2021] [Accepted: 11/09/2021] [Indexed: 12/12/2022] Open
Abstract
Rhythm disturbances are life-threatening cardiovascular diseases, accounting for many deaths annually worldwide. Abnormal electrical activity might arise in a structurally normal heart in response to specific triggers or as a consequence of cardiac tissue alterations, in both cases with catastrophic consequences on heart global functioning. Preclinical modeling by recapitulating human pathophysiology of rhythm disturbances is fundamental to increase the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and clinical management. In silico, in vivo, and in vitro models found variable application to dissect many congenital and acquired rhythm disturbances. In the copious list of rhythm disturbances, diseases of the conduction system, as sick sinus syndrome, Brugada syndrome, and atrial fibrillation, have found extensive preclinical modeling. In addition, the electrical remodeling as a result of other cardiovascular diseases has also been investigated in models of hypertrophic cardiomyopathy, cardiac fibrosis, as well as arrhythmias induced by other non-cardiac pathologies, stress, and drug cardiotoxicity. This review aims to offer a critical overview on the effective ability of in silico bioinformatic tools, in vivo animal studies, in vitro models to provide insights on human heart rhythm pathophysiology in case of sick sinus syndrome, Brugada syndrome, and atrial fibrillation and advance their safe and successful translation into the cardiology arena.
Collapse
Affiliation(s)
- Laura Iop
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Via Giustiniani, 2, I-35124 Padua, Italy; (S.I.); (G.C.)
| | | | | | - Francesco Tona
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Via Giustiniani, 2, I-35124 Padua, Italy; (S.I.); (G.C.)
| |
Collapse
|
11
|
A comparative review on heart ion channels, action potentials and electrocardiogram in rodents and human: extrapolation of experimental insights to clinic. Lab Anim Res 2021; 37:25. [PMID: 34496976 PMCID: PMC8424989 DOI: 10.1186/s42826-021-00102-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/26/2021] [Indexed: 11/10/2022] Open
Abstract
Electrocardiogram (ECG) is a non-invasive valuable diagnostic tool that is used in clinics for investigation and monitoring of heart electrical rhythm/conduction, ischemia/injury of heart, electrolyte disturbances and agents/drugs induced cardiac toxicity. Nowadays using animal models to study heart diseases such as electrical and mechanical disturbance is common. In addition, given to ethical consideration and availability, the use of small rodents has been a top priority for cardiovascular researchers. However, extrapolation of experimental findings from the lab to the clinic needs sufficient basic knowledge of similarities and differences between heart action potential and ECG of rodents and humans in normal and disease conditions. This review compares types of human action potentials, the dominant ion currents during action potential phases, alteration in ion channels activities in channelopathies-induced arrhythmias and the ECG appearance of mouse, rat, guinea pig, rabbit and human. Also, it briefly discusses the responsiveness and alterations in ECG following some interventions such as cardiac injury and arrhythmia induction. Overall, it provides a roadmap for researchers in selecting the best animal model/species whose studies results can be translated into clinical practice. In addition, this study will also be useful to biologists, physiologists, pharmacologists, veterinarians and physicians working in the fields of comparative physiology, pharmacology, toxicology and diseases.
Collapse
|
12
|
Rivaud MR, Delmar M, Remme CA. Heritable arrhythmia syndromes associated with abnormal cardiac sodium channel function: ionic and non-ionic mechanisms. Cardiovasc Res 2021; 116:1557-1570. [PMID: 32251506 PMCID: PMC7341171 DOI: 10.1093/cvr/cvaa082] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/01/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022] Open
Abstract
The cardiac sodium channel NaV1.5, encoded by the SCN5A gene, is responsible for the fast upstroke of the action potential. Mutations in SCN5A may cause sodium channel dysfunction by decreasing peak sodium current, which slows conduction and facilitates reentry-based arrhythmias, and by enhancing late sodium current, which prolongs the action potential and sets the stage for early afterdepolarization and arrhythmias. Yet, some NaV1.5-related disorders, in particular structural abnormalities, cannot be directly or solely explained on the basis of defective NaV1.5 expression or biophysics. An emerging concept that may explain the large disease spectrum associated with SCN5A mutations centres around the multifunctionality of the NaV1.5 complex. In this alternative view, alterations in NaV1.5 affect processes that are independent of its canonical ion-conducting role. We here propose a novel classification of NaV1.5 (dys)function, categorized into (i) direct ionic effects of sodium influx through NaV1.5 on membrane potential and consequent action potential generation, (ii) indirect ionic effects of sodium influx on intracellular homeostasis and signalling, and (iii) non-ionic effects of NaV1.5, independent of sodium influx, through interactions with macromolecular complexes within the different microdomains of the cardiomyocyte. These indirect ionic and non-ionic processes may, acting alone or in concert, contribute significantly to arrhythmogenesis. Hence, further exploration of these multifunctional effects of NaV1.5 is essential for the development of novel preventive and therapeutic strategies.
Collapse
Affiliation(s)
- Mathilde R Rivaud
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam UMC (location AMC), University of Amsterdam, Amsterdam Cardiovascular Sciences, Meigberdreef 15, 1105AZ Amsterdam, The Netherlands
| | - Mario Delmar
- The Leon H. Charney Division of Cardiology, New York University School of Medicine, 435 E 30th St, NSB 707, New York, NY 10016, USA
| | - Carol Ann Remme
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam UMC (location AMC), University of Amsterdam, Amsterdam Cardiovascular Sciences, Meigberdreef 15, 1105AZ Amsterdam, The Netherlands
| |
Collapse
|
13
|
Nguyen LKC, Shimizu A, Soh JEC, Komeno M, Sato A, Ogita H. Transmembrane protein 168 mutation reduces cardiomyocyte cell surface expression of Nav1.5 through αB-crystallin intracellular dynamics. J Biochem 2021; 170:577-585. [PMID: 34086898 DOI: 10.1093/jb/mvab066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/01/2021] [Indexed: 11/14/2022] Open
Abstract
Transmembrane protein 168 (TMEM168) was found to be localized on the nuclear membrane. A heterozygous mutation (c.1616G>A, p. R539Q) in TMEM168 was identified in patients with Brugada syndrome. This mutation reduced expression of cardiomyocyte sodium channel Nav1.5 via Nedd4-2 E3 ubiquitin ligase-induced ubiquitination and degradation. However, the detailed molecular mechanism provoked by the TMEM168 mutant remains unclear. Here, we demonstrated that small heat shock protein αB-crystallin, which can bind to Nav1.5 and Nedd4-2 and interfere with the association of both proteins, was strongly recruited from the cell surface to the perinuclear region because of the much higher interaction of αB-crystallin with the TMEM168 mutant than with wild-type TMEM168. Following knockdown of αB-crystallin in HL-1 cardiomyocytes, the interaction of Nav1.5 with Nedd4-2 was increased, despite a reduction of the expression level of Nav1.5. Moreover, αB-crystallin-mediated reduction of Nav1.5 expression was rescued in the presence of a proteasome inhibitor MG-132, suggesting the importance of the αB-crystallin-modulated ubiquitin-proteasome system for the stability of Nav1.5 expression. Collectively, the balance of molecular interactions among Nav1.5, Nedd4-2, and αB-crystallin plays a role in the regulation of cardiomyocyte cell surface expression of Nav1.5, and the TMEM168 mutant disturbs this balance, resulting in a decrease in Nav1.5 expression.
Collapse
Affiliation(s)
- Le Kim Chi Nguyen
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science
| | - Akio Shimizu
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science
| | - Joanne Ern Chi Soh
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science
| | - Masahiro Komeno
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science
| | - Akira Sato
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science
| | - Hisakazu Ogita
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science
| |
Collapse
|
14
|
Doisne N, Grauso M, Mougenot N, Clergue M, Souil C, Coulombe A, Guicheney P, Neyroud N. In vivo Dominant-Negative Effect of an SCN5A Brugada Syndrome Variant. Front Physiol 2021; 12:661413. [PMID: 34122134 PMCID: PMC8195286 DOI: 10.3389/fphys.2021.661413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/21/2021] [Indexed: 12/23/2022] Open
Abstract
Loss-of-function mutations in the cardiac Na+ channel α-subunit Nav1.5, encoded by SCN5A, cause Brugada syndrome (BrS), a hereditary disease characterized by sudden cardiac death due to ventricular fibrillation. We previously evidenced in vitro the dominant-negative effect of the BrS Nav1.5-R104W variant, inducing retention of wild-type (WT) channels and leading to a drastic reduction of the resulting Na+ current (INa). To explore this dominant-negative effect in vivo, we created a murine model using adeno-associated viruses (AAVs).
Collapse
Affiliation(s)
- Nicolas Doisne
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Marta Grauso
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Nathalie Mougenot
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France.,UMS_28, Sorbonne Université, Paris, France
| | - Michel Clergue
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Charlotte Souil
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Alain Coulombe
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Pascale Guicheney
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Nathalie Neyroud
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| |
Collapse
|
15
|
Carreras D, Martinez-Moreno R, Pinsach-Abuin M, Santafe MM, Gomà P, Brugada R, Scornik FS, Pérez GJ, Pagans S. Epigenetic Changes Governing Scn5a Expression in Denervated Skeletal Muscle. Int J Mol Sci 2021; 22:ijms22052755. [PMID: 33803193 PMCID: PMC7963191 DOI: 10.3390/ijms22052755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 02/06/2023] Open
Abstract
The SCN5A gene encodes the α-subunit of the voltage-gated cardiac sodium channel (NaV1.5), a key player in cardiac action potential depolarization. Genetic variants in protein-coding regions of the human SCN5A have been largely associated with inherited cardiac arrhythmias. Increasing evidence also suggests that aberrant expression of the SCN5A gene could increase susceptibility to arrhythmogenic diseases, but the mechanisms governing SCN5A expression are not yet well understood. To gain insights into the molecular basis of SCN5A gene regulation, we used rat gastrocnemius muscle four days following denervation, a process well known to stimulate Scn5a expression. Our results show that denervation of rat skeletal muscle induces the expression of the adult cardiac Scn5a isoform. RNA-seq experiments reveal that denervation leads to significant changes in the transcriptome, with Scn5a amongst the fifty top upregulated genes. Consistent with this increase in expression, ChIP-qPCR assays show enrichment of H3K27ac and H3K4me3 and binding of the transcription factor Gata4 near the Scn5a promoter region. Also, Gata4 mRNA levels are significantly induced upon denervation. Genome-wide analysis of H3K27ac by ChIP-seq suggest that a super enhancer recently described to regulate Scn5a in cardiac tissue is activated in response to denervation. Altogether, our experiments reveal that similar mechanisms regulate the expression of Scn5a in denervated muscle and cardiac tissue, suggesting a conserved pathway for SCN5A expression among striated muscles.
Collapse
Affiliation(s)
- David Carreras
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
| | - Rebecca Martinez-Moreno
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
| | - Mel·lina Pinsach-Abuin
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
| | - Manel M. Santafe
- Unit of Histology and Neurobiology, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Rovira i Virgili University, 43003 Reus, Spain;
| | - Pol Gomà
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 21005 Madrid, Spain
- Hospital Josep Trueta, 17007 Girona, Spain
| | - Fabiana S. Scornik
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 21005 Madrid, Spain
- Correspondence: (F.S.S.); (G.J.P.); (S.P.)
| | - Guillermo J. Pérez
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 21005 Madrid, Spain
- Correspondence: (F.S.S.); (G.J.P.); (S.P.)
| | - Sara Pagans
- Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain; (D.C.); (R.M.-M.); (M.P.-A.); (P.G.); (R.B.)
- Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 21005 Madrid, Spain
- Correspondence: (F.S.S.); (G.J.P.); (S.P.)
| |
Collapse
|
16
|
Pérez-Agustín A, Pinsach-Abuin M, Pagans S. Role of Non-Coding Variants in Brugada Syndrome. Int J Mol Sci 2020; 21:E8556. [PMID: 33202810 PMCID: PMC7698069 DOI: 10.3390/ijms21228556] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/15/2022] Open
Abstract
Brugada syndrome (BrS) is an inherited electrical heart disease associated with a high risk of sudden cardiac death (SCD). The genetic characterization of BrS has always been challenging. Although several cardiac ion channel genes have been associated with BrS, SCN5A is the only gene that presents definitive evidence for causality to be used for clinical diagnosis of BrS. However, more than 65% of diagnosed cases cannot be explained by variants in SCN5A or other genes. Therefore, in an important number of BrS cases, the underlying mechanisms are still elusive. Common variants, mostly located in non-coding regions, have emerged as potential modulators of the disease by affecting different regulatory mechanisms, including transcription factors (TFs), three-dimensional organization of the genome, or non-coding RNAs (ncRNAs). These common variants have been hypothesized to modulate the interindividual susceptibility of the disease, which could explain incomplete penetrance of BrS observed within families. Altogether, the study of both common and rare variants in parallel is becoming increasingly important to better understand the genetic basis underlying BrS. In this review, we aim to describe the challenges of studying non-coding variants associated with disease, re-examine the studies that have linked non-coding variants with BrS, and provide further evidence for the relevance of regulatory elements in understanding this cardiac disorder.
Collapse
Affiliation(s)
- Adrian Pérez-Agustín
- Department of Medical Sciences, School of Medicine, University of Girona, 17003 Girona, Spain;
- Biomedical Research Institute of Girona, 17190 Salt, Spain;
| | | | - Sara Pagans
- Department of Medical Sciences, School of Medicine, University of Girona, 17003 Girona, Spain;
- Biomedical Research Institute of Girona, 17190 Salt, Spain;
| |
Collapse
|
17
|
Gap-134, a Connexin43 activator, prevents age-related development of ventricular fibrosis in Scn5a +/- mice. Pharmacol Res 2020; 159:104922. [PMID: 32464326 DOI: 10.1016/j.phrs.2020.104922] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/30/2020] [Accepted: 05/10/2020] [Indexed: 01/05/2023]
Abstract
Down-regulation of Connexin43 (Cx43) has often been associated with the development of cardiac fibrosis. We showed previously that Scn5a heterozygous knockout mice (Scn5a+/-), which mimic familial progressive cardiac conduction defect, exhibit an age-dependent decrease of Cx43 expression and phosphorylation concomitantly with activation of TGF-β pathway and fibrosis development in the myocardium between 45 and 60 weeks of age. The aim of this study was to investigate whether Gap-134 prevents Cx43 down-regulation with age and fibrosis development in Scn5a+/- mice. We observed in 60-week-old Scn5a+/- mouse heart a Cx43 expression and localization remodeling correlated with fibrosis. Chronic administration of a potent and selective gap junction modifier, Gap-134 (danegaptide), between 45 and 60 weeks, increased Cx43 expression and phosphorylation on serine 368 and prevented Cx43 delocalization. Furthermore, we found that Gap-134 prevented fibrosis despite the persistence of the conduction defects and the TGF-β canonical pathway activation. In conclusion, the present study demonstrates that the age-dependent decrease of Cx43 expression is involved in the ventricular fibrotic process occurring in Scn5a+/- mice. Finally, our study suggests that gap junction modifier, such as Gap-134, could be an effective anti-fibrotic agent in the context of age-dependent fibrosis in progressive cardiac conduction disease.
Collapse
|
18
|
Shimizu A, Zankov DP, Sato A, Komeno M, Toyoda F, Yamazaki S, Makita T, Noda T, Ikawa M, Asano Y, Miyashita Y, Takashima S, Morita H, Ishikawa T, Makita N, Hitosugi M, Matsuura H, Ohno S, Horie M, Ogita H. Identification of transmembrane protein 168 mutation in familial Brugada syndrome. FASEB J 2020; 34:6399-6417. [PMID: 32175648 DOI: 10.1096/fj.201902991r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/19/2020] [Accepted: 03/02/2020] [Indexed: 12/30/2022]
Abstract
Brugada syndrome (BrS) is an inherited channelopathy responsible for almost 20% of sudden cardiac deaths in patients with nonstructural cardiac diseases. Approximately 70% of BrS patients, the causative gene mutation(s) remains unknown. In this study, we used whole exome sequencing to investigate candidate mutations in a family clinically diagnosed with BrS. A heterozygous 1616G>A substitution (R539Q mutation) was identified in the transmembrane protein 168 (TMEM168) gene of symptomatic individuals. Similar to endogenous TMEM168, both TMEM168 wild-type (WT) and mutant proteins that were ectopically induced in HL-1 cells showed nuclear membrane localization. A significant decrease in Na+ current and Nav 1.5 protein expression was observed in HL-1 cardiomyocytes expressing mutant TMEM168. Ventricular tachyarrhythmias and conduction disorders were induced in the heterozygous Tmem168 1616G>A knock-in mice by pharmacological stimulation, but not in WT mice. Na+ current was reduced in ventricular cardiomyocytes isolated from the Tmem168 knock-in heart, and Nav 1.5 expression was also impaired. This impairment was dependent on increased Nedd4-2 binding to Nav 1.5 and subsequent ubiquitination. Collectively, our results show an association between the TMEM168 1616G>A mutation and arrhythmogenesis in a family with BrS.
Collapse
Affiliation(s)
- Akio Shimizu
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Dimitar P Zankov
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan.,Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Akira Sato
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Masahiro Komeno
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Futoshi Toyoda
- Division of Cell Physiology, Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Satoru Yamazaki
- Department of Molecular Pharmacology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Toshinori Makita
- Division of Cardiac Electrophysiology, Department of Cardiovascular Center, Osaka Red Cross Hospital, Osaka, Japan
| | - Taichi Noda
- Animal Resource Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Masahito Ikawa
- Animal Resource Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Yoshihiro Asano
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yohei Miyashita
- Department of Legal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Seiji Takashima
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Hiroshi Morita
- Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Taisuke Ishikawa
- Omics Research Center, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Naomasa Makita
- Omics Research Center, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Masahito Hitosugi
- Department of Legal Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Hiroshi Matsuura
- Division of Cell Physiology, Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Seiko Ohno
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan.,Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Otsu, Japan
| | - Minoru Horie
- Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Otsu, Japan
| | - Hisakazu Ogita
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| |
Collapse
|
19
|
Li KHC, Lee S, Yin C, Liu T, Ngarmukos T, Conte G, Yan GX, Sy RW, Letsas KP, Tse G. Brugada syndrome: A comprehensive review of pathophysiological mechanisms and risk stratification strategies. IJC HEART & VASCULATURE 2020; 26:100468. [PMID: 31993492 PMCID: PMC6974766 DOI: 10.1016/j.ijcha.2020.100468] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 12/17/2022]
Abstract
Brugada syndrome (BrS) is an inherited ion channel channelopathy predisposing to ventricular arrhythmias and sudden cardiac death. Originally believed to be predominantly associated with mutations in SCN5A encoding for the cardiac sodium channel, mutations of 18 genes other than SCN5A have been implicated in the pathogenesis of BrS to date. Diagnosis is based on the presence of a spontaneous or drug-induced coved-type ST segment elevation. The predominant electrophysiological mechanism underlying BrS remains disputed, commonly revolving around the three main hypotheses based on abnormal repolarization, depolarization or current-load match. Evidence from computational modelling, pre-clinical and clinical studies illustrates that molecular abnormalities found in BrS lead to alterations in excitation wavelength (λ), which ultimately elevates arrhythmic risk. A major challenge for clinicians in managing this condition is the difficulty in predicting the subset of patients who will suffer from life-threatening ventricular arrhythmic events. Several repolarization risk markers have been used thus far, but these neglect the contributions of conduction abnormalities in the form of slowing and dispersion. Indices incorporating both repolarization and conduction based on the concept of λ have recently been proposed. These may have better predictive values than the existing markers. Current treatment options include pharmacological therapy to reduce the occurrence of arrhythmic events or to abort these episodes, and interventions such as implantable cardioverter-defibrillator insertion or radiofrequency ablation of abnormal arrhythmic substrate.
Collapse
Affiliation(s)
- Ka Hou Christien Li
- Faculty of Medicine, Newcastle University, Newcastle, United Kingdom.,Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Sharen Lee
- Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Chengye Yin
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Tachapong Ngarmukos
- Department of Medicine Faculty of Medicine Ramathibodi Hospital Mahidol University, Bangkok, Thailand
| | - Giulio Conte
- Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland
| | - Gan-Xin Yan
- Lankenau Institute for Medical Research and Lankenau Medical Center, Wynnewood, PA, USA
| | - Raymond W Sy
- Department of Cardiology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.,Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Konstantinos P Letsas
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Gary Tse
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China.,Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
| |
Collapse
|
20
|
Huo R, Hu C, Zhao L, Sun L, Wang N, Lu Y, Ye B, Deb A, Li F, Xu H. Enhancement of β-catenin/T-cell factor 4 signaling causes susceptibility to cardiac arrhythmia by suppressing Na V1.5 expression in mice. Heart Rhythm 2019; 16:1720-1728. [PMID: 31125668 PMCID: PMC7027965 DOI: 10.1016/j.hrthm.2019.05.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND β-Catenin/T-cell factor 4 (TCF4) signaling is enhanced in ischemic heart disease in which ventricular tachycardia (VT)/ventricular fibrillation occurs frequently. How this signaling links to arrhythmogenesis remains unclear. OBJECTIVE The purpose of this study was to investigate the role of β-catenin gain of function in the development of arrhythmia. METHODS A mouse model with a conditional deletion of CTNNB1 exon 3 resulting in cardiac exon 3-deleted and stabilized β-catenin (β-catΔE3) was used to determine the role of β-catenin gain of function in the regulation of cardiac rhythm. RESULTS Western blotting showed β-catΔE3 expression and significantly decreased NaV1.5 protein in CTNNB1 E3-/- and CTNNB1 E3+/- mouse hearts. Real-time qRT-PCR revealed significantly decreased NaV1.5 messenger RNA with no changes in Na+ channel β1 to β4 expression in these hearts. Immunofluorescence revealed accumulation of β-catΔE3 in the nuclei of CTNNB1 E3-/- cardiomyocytes. Immunohistochemistry demonstrated nuclear localization of β-catenin in cardiomyocytes, which was associated with significantly decreased NaV1.5 messenger RNA in human ischemic hearts. Immunoprecipitation revealed that β-catΔE3 interacted with TCF4 in CTNNB1 E3-/- cardiomyocytes. Whole-cell recordings showed that Na+ currents and depolarization and amplitude of action potentials were significantly decreased in CTNNB1 E3-/- ventricular myocytes. Electrocardiographic recordings demonstrated that in mice with cardiac CTNNB1 E3-/-, the QRS complex was prolonged and VT was induced by the Na+ channel blocker flecainide. However, cardiac function, as determined by echocardiography and heart/body weight ratios, remained unchanged. CONCLUSION Enhancement of β-catenin/TCF4 signaling led to the prolongation of the QRS complex and increase in susceptibility to VT by suppression of NaV1.5 expression and Na+ channel activity in mice.
Collapse
Affiliation(s)
- Rong Huo
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Chaowei Hu
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Limei Zhao
- Department of Pathology, Center for Cardiovascular Biology and Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington
| | - Lihua Sun
- Department of Pathology, Center for Cardiovascular Biology and Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington
| | - Ning Wang
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Yan Lu
- Department of Pathology, Center for Cardiovascular Biology and Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington; Division of Cardiology, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Bo Ye
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota
| | - Arjun Deb
- Division of Cardiology, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Faqian Li
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota
| | - Haodong Xu
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California; Department of Pathology, Center for Cardiovascular Biology and Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington.
| |
Collapse
|
21
|
Zhao L, Sun L, Lu Y, Li F, Xu H. A small-molecule LF3 abrogates β-catenin/TCF4-mediated suppression of Na V1.5 expression in HL-1 cardiomyocytes. J Mol Cell Cardiol 2019; 135:90-96. [PMID: 31419437 PMCID: PMC7088444 DOI: 10.1016/j.yjmcc.2019.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/06/2019] [Accepted: 08/13/2019] [Indexed: 12/18/2022]
Abstract
Increased nuclear β-catenin interacting with T-cell factor 4 (TCF4) affects the expression of target genes including SCN5A in ischemic heart disease, which is characterized by frequent ventricular tachycardia/fibrillation. A complex of β-catenin and TCF4 inhibits cardiac Na+ channel activity by reducing NaV1.5 expression through suppressing SCN5A promoter activity in HL-1 cardiomyocytes. LF3, a 4-thioureido-benzenesulfonamide derivative and an inhibitor of β-catenin/TCF4 interaction, has been shown to block the self-renewal capacity of cancer stem cells. We performed studies to determine if LF3 can reverse suppressive effects of β-catenin/TCF4 signaling on the expression of NaV1.5 in HL-1 cardiomyocytes. Western blotting and real-time qRT-PCR analyses showed that 10 μM LF3 significantly increased the expression of NaV1.5 but it did not alter β-catenin and TCF4 expression. Subcellular fractionation analysis demonstrated that LF3 significantly increased the levels of NaV1.5 in both membrane and cytoplasm. Whole-cell patch-clamp recordings revealed that Na+ currents were significantly increased with no changes in the steady-state parameters, activation and inactivation time constants and recovery from inactivation of Na+ channel in HL-1 cells treated with LF3. Immunoprecipitation exhibited that LF3 blocked the interaction of β-catenin and TCF4. Luciferase reporter assays performed in HEK 293 cells and HL-1 revealed that LF3 increased the SCN5A promoter activity in HL-1 cells and prevented β-catenin suppressive effect on SCN5A promoter activity in HEK 293 cells. Taken together, we conclude that LF3, an inhibitor of β-catenin/TCF4 interaction, elevates NaV1.5 expression, leading to increase Na+ channel activity in HL-1 cardiomyocytes.
Collapse
Affiliation(s)
- Limei Zhao
- Department of Pathology, Center for Cardiovascular Biology and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 90105, United States of America
| | - Lihua Sun
- Department of Pathology, Center for Cardiovascular Biology and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 90105, United States of America
| | - Yan Lu
- Department of Pathology, Center for Cardiovascular Biology and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 90105, United States of America
| | - Faqian Li
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Haodong Xu
- Department of Pathology, Center for Cardiovascular Biology and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 90105, United States of America.
| |
Collapse
|
22
|
Kelly A, Salerno S, Connolly A, Bishop M, Charpentier F, Stølen T, Smith GL. Normal interventricular differences in tissue architecture underlie right ventricular susceptibility to conduction abnormalities in a mouse model of Brugada syndrome. Cardiovasc Res 2019; 114:724-736. [PMID: 29267949 PMCID: PMC5915948 DOI: 10.1093/cvr/cvx244] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/16/2017] [Indexed: 01/09/2023] Open
Abstract
Aims Loss-of-function of the cardiac sodium channel NaV1.5 is a common feature of Brugada syndrome. Arrhythmias arise preferentially from the right ventricle (RV) despite equivalent NaV1.5 downregulation in the left ventricle (LV). The reasons for increased RV sensitivity to NaV1.5 loss-of-function mutations remain unclear. Because ventricular electrical activation occurs predominantly in the transmural axis, we compare RV and LV transmural electrophysiology to determine the underlying cause of the asymmetrical conduction abnormalities in Scn5a haploinsufficient mice (Scn5a+/−). Methods and results Optical mapping and two-photon microscopy in isolated-perfused mouse hearts demonstrated equivalent depression of transmural conduction velocity (CV) in the LV and RV of Scn5a+/− vs. wild-type littermates. Only RV transmural conduction was further impaired when challenged with increased pacing frequencies. Epicardial dispersion of activation and beat-to-beat variation in activation time were increased only in the RV of Scn5a+/− hearts. Analysis of confocal and histological images revealed larger intramural clefts between cardiomyocyte layers in the RV vs. LV, independent of genotype. Acute sodium current inhibition in wild type hearts using tetrodotoxin reproduced beat-to-beat activation variability and frequency-dependent CV slowing in the RV only, with the LV unaffected. The influence of clefts on conduction was examined using a two-dimensional monodomain computational model. When peak sodium channel conductance was reduced to 50% of normal the presence of clefts between cardiomyocyte layers reproduced the activation variability and conduction phenotype observed experimentally. Conclusions Normal structural heterogeneities present in the RV are responsible for increased vulnerability to conduction slowing in the presence of reduced sodium channel function. Heterogeneous conduction slowing seen in the RV will predispose to functional block and the initiation of re-entrant ventricular arrhythmias.
Collapse
Affiliation(s)
- Allen Kelly
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway.,Institute of Cardiovascular & Medical Sciences, University of Glasgow G12 8QQ, UK
| | - Simona Salerno
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway
| | - Adam Connolly
- Division of Imaging Sciences and Biomedical Engineering, Department of Biomedical Engineering, Kings College London SE1 7EH, UK
| | - Martin Bishop
- Division of Imaging Sciences and Biomedical Engineering, Department of Biomedical Engineering, Kings College London SE1 7EH, UK
| | | | - Tomas Stølen
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway
| | - Godfrey L Smith
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway.,Institute of Cardiovascular & Medical Sciences, University of Glasgow G12 8QQ, UK
| |
Collapse
|
23
|
Abstract
Brugada syndrome is an inherited, rare cardiac arrhythmogenic disease, associated with sudden cardiac death. It accounts for up to 20% of sudden deaths in patients without structural cardiac abnormalities. The majority of mutations involve the cardiac sodium channel gene SCN5A and give rise to classical abnormal electrocardiogram with ST segment elevation in the right precordial leads V1 to V3 and a predisposition to ventricular fibrillation. The pathophysiological mechanisms of Brugada syndrome have been investigated using model systems including transgenic mice, canine heart preparations, and expression systems to study different SCN5A mutations. These models have a number of limitations. The recent development of pluripotent stem cell technology creates an opportunity to study cardiomyocytes derived from patients and healthy individuals. To date, only a few studies have been done using Brugada syndrome patient-specific iPS-CM, which have provided novel insights into the mechanisms and pathophysiology of Brugada syndrome. This review provides an evaluation of the strengths and limitations of each of these model systems and summarizes the key mechanisms that have been identified to date.
Collapse
|
24
|
Novel Mechanistic Roles for Ankyrin-G in Cardiac Remodeling and Heart Failure. JACC Basic Transl Sci 2018; 3:675-689. [PMID: 30456339 PMCID: PMC6234521 DOI: 10.1016/j.jacbts.2018.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/05/2018] [Accepted: 07/31/2018] [Indexed: 12/25/2022]
Abstract
The pathogenesis of human heart failure is complex, and the creation of new therapeutic strategies for human heart failure is critical. Identifying the molecular pathways underlying heart failure is important to define potential new therapeutic targets. Ankyrin polypeptides serve to target and stabilize membrane proteins in cardiomyocytes. Ankyrin-G levels are altered in humans and mice with heart failure, and mice lacking ankyrin-G in cardiomyocytes develop cardiomyopathy and systolic dysfunction. Mechanistically, ankyrin-G is necessary for the expression and localization of critical myocyte proteins essential for regulating cardiac structural and electrical activity.
Ankyrin polypeptides are intracellular proteins responsible for targeting cardiac membrane proteins. Here, the authors demonstrate that ankyrin-G plays an unexpected role in normal compensatory physiological remodeling in response to myocardial stress and aging; the authors implicate disruption of ankyrin-G in human heart failure. Mechanistically, the authors illustrate that ankyrin-G serves as a key nodal protein required for cardiac myofilament integration with the intercalated disc. Their data define novel in vivo mechanistic roles for ankyrin-G, implicate ankyrin-G as necessary for compensatory cardiac physiological remodeling under stress, and implicate disruption of ankyrin-G in the development and progression of human heart failure.
Collapse
Key Words
- AnkG, ankyrin-G
- DSP, desmoplakin
- ECG, electrocardiogram
- HF, heart failure
- LV, left ventricular
- Nav1.5
- PBS, phosphate-buffered saline
- PKP2, plakophilin-2
- TAC, transverse aortic constriction
- TUNEL, terminal deoxynucleotidyl transferase dUTP nick-end labeling
- WT, wild-type
- ankyrin
- arrhythmia
- cKO, cardiomyocyte-specific knockout
- cytoskeleton
- heart failure
- ion channel
Collapse
|
25
|
Derangeon M, Montnach J, Cerpa CO, Jagu B, Patin J, Toumaniantz G, Girardeau A, Huang CLH, Colledge WH, Grace AA, Baró I, Charpentier F. Transforming growth factor β receptor inhibition prevents ventricular fibrosis in a mouse model of progressive cardiac conduction disease. Cardiovasc Res 2017; 113:464-474. [PMID: 28339646 DOI: 10.1093/cvr/cvx026] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/16/2017] [Indexed: 01/12/2023] Open
Abstract
Aims Loss-of-function mutations in SCN5A, the gene encoding NaV1.5 channel, have been associated with inherited progressive cardiac conduction disease (PCCD). We have proposed that Scn5a heterozygous knock-out (Scn5a+/-) mice, which are characterized by ventricular fibrotic remodelling with ageing, represent a model for PCCD. Our objectives were to identify the molecular pathway involved in fibrosis development and prevent its activation. Methods and results Our study shows that myocardial interstitial fibrosis occurred in Scn5a+/- mice only after 45 weeks of age. Fibrosis was triggered by transforming growth factor β (TGF-β) pathway activation. Younger Scn5a+/- mice were characterized by a higher connexin 43 expression than wild-type (WT) mice. After the age of 45 weeks, connexin 43 expression decreased in both WT and Scn5a+/- mice, although the decrease was larger in Scn5a+/- mice. Chronic inhibition of cardiac sodium current with flecainide (50 mg/kg/day p.o) in WT mice from the age of 6 weeks to the age of 60 weeks did not lead to TGF-β pathway activation and fibrosis. Chronic inhibition of TGF-β receptors with GW788388 (5 mg/kg/day p.o.) in Scn5a+/- mice from the age of 45 weeks to the age of 60 weeks prevented the occurrence of fibrosis. However, current data could not detect reduction in QRS duration with GW788388. Conclusion Myocardial fibrosis secondary to a loss of NaV1.5 is triggered by TGF-β signalling pathway. Those events are more likely secondary to the decreased NaV1.5 sarcolemmal expression rather than the decreased Na+ current per se. TGF-β receptor inhibition prevents age-dependent development of ventricular fibrosis in Scn5a+/- mouse.
Collapse
Affiliation(s)
- Mickael Derangeon
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Jérôme Montnach
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Cynthia Ore Cerpa
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Benoit Jagu
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Justine Patin
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Gilles Toumaniantz
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Aurore Girardeau
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Christopher L H Huang
- The Section of Cardiovascular Biology, Departments of Biochemistry and Physiology, University of Cambridge, Downing street, Cambridge CB23EG, UK
| | - William H Colledge
- The Section of Cardiovascular Biology, Departments of Biochemistry and Physiology, University of Cambridge, Downing street, Cambridge CB23EG, UK
| | - Andrew A Grace
- The Section of Cardiovascular Biology, Departments of Biochemistry and Physiology, University of Cambridge, Downing street, Cambridge CB23EG, UK
| | - Isabelle Baró
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Flavien Charpentier
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France.,CHU Nantes, Alexis Ricordeau, Nantes F-44000, France
| |
Collapse
|
26
|
Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
Collapse
Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
27
|
Tarradas A, Pinsach-Abuin ML, Mackintosh C, Llorà-Batlle O, Pérez-Serra A, Batlle M, Pérez-Villa F, Zimmer T, Garcia-Bassets I, Brugada R, Beltran-Alvarez P, Pagans S. Transcriptional regulation of the sodium channel gene (SCN5A) by GATA4 in human heart. J Mol Cell Cardiol 2016; 102:74-82. [PMID: 27894866 DOI: 10.1016/j.yjmcc.2016.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 10/07/2016] [Accepted: 10/24/2016] [Indexed: 01/12/2023]
Abstract
Aberrant expression of the sodium channel gene (SCN5A) has been proposed to disrupt cardiac action potential and cause human cardiac arrhythmias, but the mechanisms of SCN5A gene regulation and dysregulation still remain largely unexplored. To gain insight into the transcriptional regulatory networks of SCN5A, we surveyed the promoter and first intronic regions of the SCN5A gene, predicting the presence of several binding sites for GATA transcription factors (TFs). Consistent with this prediction, chromatin immunoprecipitation (ChIP) and sequential ChIP (Re-ChIP) assays show co-occupancy of cardiac GATA TFs GATA4 and GATA5 on promoter and intron 1 SCN5A regions in fresh-frozen human left ventricle samples. Gene reporter experiments show GATA4 and GATA5 synergism in the activation of the SCN5A promoter, and its dependence on predicted GATA binding sites. GATA4 and GATA6 mRNAs are robustly expressed in fresh-frozen human left ventricle samples as measured by highly sensitive droplet digital PCR (ddPCR). GATA5 mRNA is marginally but still clearly detected in the same samples. Importantly, GATA4 mRNA levels are strongly and positively correlated with SCN5A transcript levels in the human heart. Together, our findings uncover a novel mechanism of GATA TFs in the regulation of the SCN5A gene in human heart tissue. Our studies suggest that GATA5 but especially GATA4 are main contributors to SCN5A gene expression, thus providing a new paradigm of SCN5A expression regulation that may shed new light into the understanding of cardiac disease.
Collapse
Affiliation(s)
- Anna Tarradas
- Medical Sciences Department, School of Medicine, University of Girona, 17071 Girona, Spain; Institut d'Investigació Biomèdica de Girona, 17190 Salt, Spain
| | - Mel Lina Pinsach-Abuin
- Medical Sciences Department, School of Medicine, University of Girona, 17071 Girona, Spain; Institut d'Investigació Biomèdica de Girona, 17190 Salt, Spain; School of Medicine, University of California San Diego, La Jolla, CA 92093-0648, USA
| | - Carlos Mackintosh
- School of Medicine, University of California San Diego, La Jolla, CA 92093-0648, USA
| | - Oriol Llorà-Batlle
- Medical Sciences Department, School of Medicine, University of Girona, 17071 Girona, Spain; Institut d'Investigació Biomèdica de Girona, 17190 Salt, Spain
| | - Alexandra Pérez-Serra
- Medical Sciences Department, School of Medicine, University of Girona, 17071 Girona, Spain; Institut d'Investigació Biomèdica de Girona, 17190 Salt, Spain
| | - Montserrat Batlle
- Thorax Institute, Cardiology Department, Hospital Clínic, University of Barcelona, Institute of Biomedical Research August Pi i Sunyer, 08036 Barcelona, Spain
| | - Félix Pérez-Villa
- Thorax Institute, Cardiology Department, Hospital Clínic, University of Barcelona, Institute of Biomedical Research August Pi i Sunyer, 08036 Barcelona, Spain
| | - Thomas Zimmer
- Institute for Physiology II, University Hospital, 07743 Jena, Germany
| | - Ivan Garcia-Bassets
- School of Medicine, University of California San Diego, La Jolla, CA 92093-0648, USA
| | - Ramon Brugada
- Medical Sciences Department, School of Medicine, University of Girona, 17071 Girona, Spain; Institut d'Investigació Biomèdica de Girona, 17190 Salt, Spain; Hospital Universitari Dr. Josep Trueta, 17001 Girona, Spain
| | - Pedro Beltran-Alvarez
- Medical Sciences Department, School of Medicine, University of Girona, 17071 Girona, Spain; Institut d'Investigació Biomèdica de Girona, 17190 Salt, Spain; School of Biological, Biomedical, and Environmental Sciences, University of Hull, HU6 7RX, Hull, UK.
| | - Sara Pagans
- Medical Sciences Department, School of Medicine, University of Girona, 17071 Girona, Spain; Institut d'Investigació Biomèdica de Girona, 17190 Salt, Spain.
| |
Collapse
|
28
|
Tse G, Liu T, Li KHC, Laxton V, Chan YWF, Keung W, Li RA, Yan BP. Electrophysiological Mechanisms of Brugada Syndrome: Insights from Pre-clinical and Clinical Studies. Front Physiol 2016; 7:467. [PMID: 27803673 PMCID: PMC5067537 DOI: 10.3389/fphys.2016.00467] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/27/2016] [Indexed: 12/19/2022] Open
Abstract
Brugada syndrome (BrS), is a primary electrical disorder predisposing affected individuals to sudden cardiac death via the development of ventricular tachycardia and fibrillation (VT/VF). Originally, BrS was linked to mutations in the SCN5A, which encodes for the cardiac Na+ channel. To date, variants in 19 genes have been implicated in this condition, with 11, 5, 3, and 1 genes affecting the Na+, K+, Ca2+, and funny currents, respectively. Diagnosis of BrS is based on ECG criteria of coved- or saddle-shaped ST segment elevation and/or T-wave inversion with or without drug challenge. Three hypotheses based on abnormal depolarization, abnormal repolarization, and current-load-mismatch have been put forward to explain the electrophysiological mechanisms responsible for BrS. Evidence from computational modeling, pre-clinical, and clinical studies illustrates that molecular abnormalities found in BrS lead to alterations in excitation wavelength (λ), which ultimately elevates arrhythmic risk. A major challenge for clinicians in managing this condition is the difficulty in predicting the subset of patients who will suffer from life-threatening VT/VF. Several repolarization risk markers have been used thus far, but these neglect the contributions of conduction abnormalities in the form of slowing and dispersion. Indices incorporating both repolarization and conduction and based on the concept of λ have recently been proposed. These may have better predictive values than the existing markers.
Collapse
Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, Chinese University of Hong KongHong Kong, Hong Kong
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong KongHong Kong, Hong Kong
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical UniversityTianjin, China
| | - Ka H. C. Li
- Faculty of Medicine, Newcastle UniversityNewcastle, UK
| | - Victoria Laxton
- Intensive Care Department, Royal Brompton and Harefield NHS TrustLondon, UK
| | - Yin W. F. Chan
- School of Biological Sciences, University of CambridgeCambridge, UK
| | - Wendy Keung
- Stem Cell and Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong
| | - Ronald A. Li
- Ming Wai Lau Centre for Reparative Medicine, Karolinska InstitutetSolna, Sweden
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, Chinese University of Hong KongHong Kong, Hong Kong
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
| |
Collapse
|
29
|
Choy L, Yeo JM, Tse V, Chan SP, Tse G. Cardiac disease and arrhythmogenesis: Mechanistic insights from mouse models. IJC HEART & VASCULATURE 2016; 12:1-10. [PMID: 27766308 PMCID: PMC5064289 DOI: 10.1016/j.ijcha.2016.05.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 05/02/2016] [Indexed: 12/19/2022]
Abstract
The mouse is the second mammalian species, after the human, in which substantial amount of the genomic information has been analyzed. With advances in transgenic technology, mutagenesis is now much easier to carry out in mice. Consequently, an increasing number of transgenic mouse systems have been generated for the study of cardiac arrhythmias in ion channelopathies and cardiomyopathies. Mouse hearts are also amenable to physical manipulation such as coronary artery ligation and transverse aortic constriction to induce heart failure, radiofrequency ablation of the AV node to model complete AV block and even implantation of a miniature pacemaker to induce cardiac dyssynchrony. Last but not least, pharmacological models, despite being simplistic, have enabled us to understand the physiological mechanisms of arrhythmias and evaluate the anti-arrhythmic properties of experimental agents, such as gap junction modulators, that may be exert therapeutic effects in other cardiac diseases. In this article, we examine these in turn, demonstrating that primary inherited arrhythmic syndromes are now recognized to be more complex than abnormality in a particular ion channel, involving alterations in gene expression and structural remodelling. Conversely, in cardiomyopathies and heart failure, mutations in ion channels and proteins have been identified as underlying causes, and electrophysiological remodelling are recognized pathological features. Transgenic techniques causing mutagenesis in mice are extremely powerful in dissecting the relative contributions of different genes play in producing disease phenotypes. Mouse models can serve as useful systems in which to explore how protein defects contribute to arrhythmias and direct future therapy.
Collapse
Affiliation(s)
- Lois Choy
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Jie Ming Yeo
- School of Medicine, Imperial College London, SW7 2AZ, UK
| | - Vivian Tse
- Department of Physiology, McGill University, Canada
| | - Shing Po Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Gary Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| |
Collapse
|
30
|
Lang CN, Koren G, Odening KE. Transgenic rabbit models to investigate the cardiac ion channel disease long QT syndrome. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:142-56. [PMID: 27210307 DOI: 10.1016/j.pbiomolbio.2016.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/01/2016] [Indexed: 12/13/2022]
Abstract
Long QT syndrome (LQTS) is a rare inherited channelopathy caused mainly by different mutations in genes encoding for cardiac K(+) or Na(+) channels, but can also be caused by commonly used ion-channel-blocking and QT-prolonging drugs, thus affecting a much larger population. To develop novel diagnostic and therapeutic strategies to improve the clinical management of these patients, a thorough understanding of the pathophysiological mechanisms of arrhythmogenesis and potential pharmacological targets is needed. Drug-induced and genetic animal models of various species have been generated and have been instrumental for identifying pro-arrhythmic triggers and important characteristics of the arrhythmogenic substrate in LQTS. However, due to species differences in features of cardiac electrical function, these different models do not entirely recapitulate all aspects of the human disease. In this review, we summarize advantages and shortcomings of different drug-induced and genetically mediated LQTS animal models - focusing on mouse and rabbit models since these represent the most commonly used small animal models for LQTS that can be subjected to genetic manipulation. In particular, we highlight the different aspects of arrhythmogenic mechanisms, pro-arrhythmic triggering factors, anti-arrhythmic agents, and electro-mechanical dysfunction investigated in transgenic LQTS rabbit models and their translational application for the clinical management of LQTS patients in detail. Transgenic LQTS rabbits have been instrumental to increase our understanding of the role of spatial and temporal dispersion of repolarization to provide an arrhythmogenic substrate, genotype-differences in the mechanisms for early afterdepolarization formation and arrhythmia maintenance, mechanisms of hormonal modification of arrhythmogenesis and regional heterogeneities in electro-mechanical dysfunction in LQTS.
Collapse
Affiliation(s)
- C N Lang
- Department of Cardiology and Angiology I, University Heart Center Freiburg, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - G Koren
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - K E Odening
- Department of Cardiology and Angiology I, University Heart Center Freiburg, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany.
| |
Collapse
|
31
|
Splicing misregulation of SCN5A contributes to cardiac-conduction delay and heart arrhythmia in myotonic dystrophy. Nat Commun 2016; 7:11067. [PMID: 27063795 PMCID: PMC4831019 DOI: 10.1038/ncomms11067] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 02/16/2016] [Indexed: 12/11/2022] Open
Abstract
Myotonic dystrophy (DM) is caused by the expression of mutant RNAs containing expanded CUG repeats that sequester muscleblind-like (MBNL) proteins, leading to alternative splicing changes. Cardiac alterations, characterized by conduction delays and arrhythmia, are the second most common cause of death in DM. Using RNA sequencing, here we identify novel splicing alterations in DM heart samples, including a switch from adult exon 6B towards fetal exon 6A in the cardiac sodium channel, SCN5A. We find that MBNL1 regulates alternative splicing of SCN5A mRNA and that the splicing variant of SCN5A produced in DM presents a reduced excitability compared with the control adult isoform. Importantly, reproducing splicing alteration of Scn5a in mice is sufficient to promote heart arrhythmia and cardiac-conduction delay, two predominant features of myotonic dystrophy. In conclusion, misregulation of the alternative splicing of SCN5A may contribute to a subset of the cardiac dysfunctions observed in myotonic dystrophy. Patients with myotonic dystrophy (MD) suffer from severe cardiac issues of unknown aetiology. Freyermuth et al. show that fatal changes in cardiac electrophysiological properties in humans and mice with MD may arise from misregulation of the alternative splicing of the cardiac Na+ channel SCN5A transcript, resulting in expression of its fetal form.
Collapse
|
32
|
Jeevaratnam K, Guzadhur L, Goh YM, Grace AA, Huang CLH. Sodium channel haploinsufficiency and structural change in ventricular arrhythmogenesis. Acta Physiol (Oxf) 2016; 216:186-202. [PMID: 26284956 DOI: 10.1111/apha.12577] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/11/2015] [Accepted: 07/24/2015] [Indexed: 12/19/2022]
Abstract
Normal cardiac excitation involves orderly conduction of electrical activation and recovery dependent upon surface membrane, voltage-gated, sodium (Na(+) ) channel α-subunits (Nav 1.5). We summarize experimental studies of physiological and clinical consequences of loss-of-function Na(+) channel mutations. Of these conditions, Brugada syndrome (BrS) and progressive cardiac conduction defect (PCCD) are associated with sudden, often fatal, ventricular tachycardia (VT) or fibrillation. Mouse Scn5a(+/-) hearts replicate important clinical phenotypes modelling these human conditions. The arrhythmic phenotype is associated not only with the primary biophysical change but also with additional, anatomical abnormalities, in turn dependent upon age and sex, each themselves exerting arrhythmic effects. Available evidence suggests a unified binary scheme for the development of arrhythmia in both BrS and PCCD. Previous biophysical studies suggested that Nav 1.5 deficiency produces a background electrophysiological defect compromising conduction, thereby producing an arrhythmic substrate unmasked by flecainide or ajmaline challenge. More recent reports further suggest a progressive decline in conduction velocity and increase in its dispersion particularly in ageing male Nav 1.5 haploinsufficient compared to WT hearts. This appears to involve a selective appearance of slow conduction at the expense of rapidly conducting pathways with changes in their frequency distributions. These changes were related to increased cardiac fibrosis. It is thus the combination of the structural and biophysical changes both accentuating arrhythmic substrate that may produce arrhythmic tendency. This binary scheme explains the combined requirement for separate, biophysical and structural changes, particularly occurring in ageing Nav 1.5 haploinsufficient males in producing clinical arrhythmia.
Collapse
Affiliation(s)
- K. Jeevaratnam
- Faculty of Health and Medical Science; University of Surrey; Guilford UK
- Perdana University - Royal College of Surgeons Ireland; Serdang Selangor Darul Ehsan Malaysia
| | - L. Guzadhur
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Niche Science & Technology; Richmond UK
| | - Y. M. Goh
- Department of Preclinical Sciences; Faculty of Veterinary Medicine; University Putra Malaysia; Serdang Selangor Darul Ehsan Malaysia
| | - A. A. Grace
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
| | - C. L.-H. Huang
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Physiological Laboratory; University of Cambridge; Cambridge UK
| |
Collapse
|
33
|
Makara MA, Curran J, Little SC, Musa H, Polina I, Smith SA, Wright PJ, Unudurthi SD, Snyder J, Bennett V, Hund TJ, Mohler PJ. Ankyrin-G coordinates intercalated disc signaling platform to regulate cardiac excitability in vivo. Circ Res 2014; 115:929-38. [PMID: 25239140 DOI: 10.1161/circresaha.115.305154] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
RATIONALE Nav1.5 (SCN5A) is the primary cardiac voltage-gated Nav channel. Nav1.5 is critical for cardiac excitability and conduction, and human SCN5A mutations cause sinus node dysfunction, atrial fibrillation, conductional abnormalities, and ventricular arrhythmias. Further, defects in Nav1.5 regulation are linked with malignant arrhythmias associated with human heart failure. Consequently, therapies to target select Nav1.5 properties have remained at the forefront of cardiovascular medicine. However, despite years of investigation, the fundamental pathways governing Nav1.5 membrane targeting, assembly, and regulation are still largely undefined. OBJECTIVE Define the in vivo mechanisms underlying Nav1.5 membrane regulation. METHODS AND RESULTS Here, we define the molecular basis of an Nav channel regulatory platform in heart. Using new cardiac-selective ankyrin-G(-/-) mice (conditional knock-out mouse), we report that ankyrin-G targets Nav1.5 and its regulatory protein calcium/calmodulin-dependent kinase II to the intercalated disc. Mechanistically, βIV-spectrin is requisite for ankyrin-dependent targeting of calcium/calmodulin-dependent kinase II-δ; however, βIV-spectrin is not essential for ankyrin-G expression. Ankyrin-G conditional knock-out mouse myocytes display decreased Nav1.5 expression/membrane localization and reduced INa associated with pronounced bradycardia, conduction abnormalities, and ventricular arrhythmia in response to Nav channel antagonists. Moreover, we report that ankyrin-G links Nav channels with broader intercalated disc signaling/structural nodes, as ankyrin-G loss results in reorganization of plakophilin-2 and lethal arrhythmias in response to β-adrenergic stimulation. CONCLUSIONS Our findings provide the first in vivo data for the molecular pathway required for intercalated disc Nav1.5 targeting/regulation in heart. Further, these new data identify the basis of an in vivo cellular platform critical for membrane recruitment and regulation of Nav1.5.
Collapse
Affiliation(s)
- Michael A Makara
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Jerry Curran
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Sean C Little
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Hassan Musa
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Iuliia Polina
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Sakima A Smith
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Patrick J Wright
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Sathya D Unudurthi
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Jed Snyder
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Vann Bennett
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Thomas J Hund
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.)
| | - Peter J Mohler
- From The Dorothy M. Davis Heart & Lung Research Institute (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., S.D.U., J.S., T.J.H., P.J.M. ), Departments of Internal Medicine (S.A.S., P.J.M.), and Physiology and Cell Biology (M.A.M., J.C., S.C.L., H.M., I.P., S.A.S., P.J.W., P.J.M.), The Ohio State University Wexner Medical Center, Columbus; Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus (S.D.U., J.S., T.J.H.); and Howard Hughes Medical Institute, Department of Biochemistry, Duke University Medical Center, Durham, NC (V.B.).
| |
Collapse
|
34
|
Cai B, Wang N, Mao W, You T, Lu Y, Li X, Ye B, Li F, Xu H. Deletion of FoxO1 leads to shortening of QRS by increasing Na(+) channel activity through enhanced expression of both cardiac NaV1.5 and β3 subunit. J Mol Cell Cardiol 2014; 74:297-306. [PMID: 24956219 PMCID: PMC4158923 DOI: 10.1016/j.yjmcc.2014.06.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 06/10/2014] [Accepted: 06/12/2014] [Indexed: 12/19/2022]
Abstract
Our in vitro studies revealed that a transcription factor, Forkhead box protein O1 (FoxO1), negatively regulates the expression of NaV1.5, a main α subunit of the cardiac Na(+) channel, by altering the promoter activity of SCN5a in HL-1 cardiomyocytes. The in vivo role of FoxO1 in the regulation of cardiac NaV1.5 expression remains unknown. The present study aimed to define the role of FoxO1 in the regulation of NaV1.5 expression and cardiac Na(+) channel activity in mouse ventricular cardiomyocytes and assess the cardiac electrophysiological phenotype of mice with cardiac FoxO1 deletion. Tamoxifen-induced and cardiac-specific FoxO1 deletion was confirmed by polymerase chain reaction (PCR). Cardiac FoxO1 deletion failed to result in either cardiac functional changes or hypertrophy as assessed by echocardiography and individual ventricular cell capacitances, respectively. Western blotting showed that FoxO1 was significantly decreased while NaV1.5 protein level was significantly increased in mouse hearts with FoxO1 deletion. Reverse transcription-PCR (RT-PCR) revealed that FoxO1 deletion led to an increase in NaV1.5 and Na(+) channel subunit β3 mRNA, but not β1, 2, and 4, or connexin 43. Whole patch-clamp recordings demonstrated that cardiac Na(+) currents were significantly augmented by FoxO1 deletion without affecting the steady-state activation and inactivation, leading to accelerated depolarization of action potentials in mouse ventricular cardiomyocytes. Electrocardiogram recordings showed that the QRS complex was significantly shortened and the P wave amplitude was significantly increased in conscious and unrestrained mice with cardiac FoxO1 deletion. NaV1.5 expression was decreased in the peri-infarct (border-zone) of mice with myocardial infarction and FoxO1 accumulated in the cardiomyocyte nuclei of chronic ischemic human hearts. Our findings indicate that FoxO1 plays an important role in the regulation of NaV1.5 and β3 subunit expressions as well as Na(+) channel activity in the heart and that FoxO1 is involved in the modulation of NaV1.5 expression in ischemic heart disease.
Collapse
Affiliation(s)
- Benzhi Cai
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Ning Wang
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA; Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Weike Mao
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Tao You
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Yan Lu
- Aab Cardiovascular Research Institute, University of Rochester Medical Center, Rochester, NY, USA; Division of Cardiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Xiang Li
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Bo Ye
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Faqian Li
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Haodong Xu
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA; Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Aab Cardiovascular Research Institute, University of Rochester Medical Center, Rochester, NY, USA.
| |
Collapse
|
35
|
Whole-exome sequencing identifies Y1495X of SCN5A to be associated with familial conduction disease and sudden death. Sci Rep 2014; 4:5616. [PMID: 25010007 PMCID: PMC5375973 DOI: 10.1038/srep05616] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 06/20/2014] [Indexed: 02/07/2023] Open
Abstract
SCN5A mutations have been reported to underlie a variety of inherited arrhythmias, while the complex overlapping phenotype, especially with congenital heart disease (CHD), is rarely reported. The 48-year-old proband underwent a recent syncope during rest. A CHD (tetralogy of Fallot) and conduction disease was revealed by echocardiogram and ultrasonic cardiogram examination. We combined whole-exome sequencing (WES) and bioinformatics strategies to identify the pathogenic gene for this autosomal-dominant cardiac conduction disease (CCD) in a multi-generation pedigree. We examined four members of this family, including three affected and one unaffected. A novel nonsense mutation (Y1495X) in SCN5A was identified in the affected family members. This mutation is predicted to generate a truncated SCN5A protein, which could result in the loss of sodium current, a defined mechanism of SCN5A related arrhythmias. Our study provides evidence that WES is a highly effective approach for genetic analyses of rare clinical phenotypes. Our study also offers accurate genetic testing information for those yet clinically negative relatives.
Collapse
|
36
|
van den Boogaard M, Smemo S, Burnicka-Turek O, Arnolds DE, van de Werken HJG, Klous P, McKean D, Muehlschlegel JD, Moosmann J, Toka O, Yang XH, Koopmann TT, Adriaens ME, Bezzina CR, de Laat W, Seidman C, Seidman JG, Christoffels VM, Nobrega MA, Barnett P, Moskowitz IP. A common genetic variant within SCN10A modulates cardiac SCN5A expression. J Clin Invest 2014; 124:1844-52. [PMID: 24642470 DOI: 10.1172/jci73140] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 01/09/2014] [Indexed: 12/19/2022] Open
Abstract
Variants in SCN10A, which encodes a voltage-gated sodium channel, are associated with alterations of cardiac conduction parameters and the cardiac rhythm disorder Brugada syndrome; however, it is unclear how SCN10A variants promote dysfunctional cardiac conduction. Here we showed by high-resolution 4C-seq analysis of the Scn10a-Scn5a locus in murine heart tissue that a cardiac enhancer located in Scn10a, encompassing SCN10A functional variant rs6801957, interacts with the promoter of Scn5a, a sodium channel-encoding gene that is critical for cardiac conduction. We observed that SCN5A transcript levels were several orders of magnitude higher than SCN10A transcript levels in both adult human and mouse heart tissue. Analysis of BAC transgenic mouse strains harboring an engineered deletion of the enhancer within Scn10a revealed that the enhancer was essential for Scn5a expression in cardiac tissue. Furthermore, the common SCN10A variant rs6801957 modulated Scn5a expression in the heart. In humans, the SCN10A variant rs6801957, which correlated with slowed conduction, was associated with reduced SCN5A expression. These observations establish a genomic mechanism for how a common genetic variation at SCN10A influences cardiac physiology and predisposes to arrhythmia.
Collapse
|
37
|
Nerbonne JM. Mouse models of arrhythmogenic cardiovascular disease: challenges and opportunities. Curr Opin Pharmacol 2014; 15:107-14. [PMID: 24632325 DOI: 10.1016/j.coph.2014.02.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 12/27/2022]
Abstract
Arrhythmogenic cardiovascular disease is associated with significant morbidity and mortality and, in spite of therapeutic advances, remains an enormous public health burden. The scope of this problem motivates efforts to delineate the molecular, cellular and systemic mechanisms underlying increased arrhythmia risk in inherited and acquired cardiac and systemic disease. The mouse is used increasingly in these efforts owing to the ease with which genetic strategies can be exploited and mechanisms can be probed. The question then arises whether the mouse has proven to be a useful model system to delineate arrhythmogenic cardiovascular disease mechanisms. Rather than trying to provide a definite answer, the goal here is to consider the issues that arise when using mouse models and to highlight the opportunities.
Collapse
Affiliation(s)
- Jeanne M Nerbonne
- Department of Developmental Biology, Washington University Medical School, St. Louis, MO 63110, USA; Department of Internal Medicine, Washington University Medical School, St. Louis, MO 63110, USA.
| |
Collapse
|
38
|
Changes in Cx43 and NaV1.5 expression precede the occurrence of substantial fibrosis in calcineurin-induced murine cardiac hypertrophy. PLoS One 2014; 9:e87226. [PMID: 24498049 PMCID: PMC3909068 DOI: 10.1371/journal.pone.0087226] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 12/20/2013] [Indexed: 11/19/2022] Open
Abstract
In mice, the calcium-dependent phosphatase calcineurin A (CnA) induces a transcriptional pathway leading to pathological cardiac hypertrophy. Interestingly, induction of CnA has been frequently noticed in human hypertrophic and failing hearts. Independently, the arrhythmia vulnerability of such hearts has been regularly associated with remodeling of parameters determining electrical conduction (expression level of connexin43 (Cx43) and NaV1.5, connective tissue architecture), for which the precise molecular basis and sequence of events is still unknown. Recently, we observed reduced Cx43 and NaV1.5 expression in 4-week old mouse hearts, overexpressing a constitutively active form of CnA (MHC-CnA model), but the order of events is still unknown. Therefore, three key parameters of conduction (Cx43, NaV1.5 and connective tissue expression) were characterized in MHC-CnA ventricles versus wild-type (WT) during postnatal development on a weekly basis. At postnatal week 1, CnA overexpression induced cardiac hypertrophy in MHC-CnA. Moreover, protein and RNA levels of both Cx43 and NaV1.5 were reduced by at least 50% as compared to WT. Cx43 immunoreactive signal was reduced at week 2 in MHC-CnA. At postnatal week 3, Cx43 was less phosphorylated and RNA level of Cx43 normalized to WT values, although the protein level was still reduced. Additionally, MHC-CnA hearts displayed substantial fibrosis relative to WT, which was accompanied by increased RNA levels for genes previously associated with fibrosis such as Col1a1, Col1a2, Col3a1, Tgfb1, Ctgf, Timp1 and microRNA miR-21. In MHC-CnA, reduction in Cx43 and NaV1.5 expression thus coincided with overexpression of CnA and hypertrophy development and preceded significant presence of fibrosis. At postnatal week 4 the alterations in conductional parameters observed in the MHC-CnA model lead to abnormal conduction and arrhythmias, similar to those observed in cardiac remodeling in heart failure patients. The MHC-CnA model, therefore, provides for a unique model to resolve the molecular origin of conductional remodeling in detail.
Collapse
|
39
|
Gütter C, Benndorf K, Zimmer T. Characterization of N-terminally mutated cardiac Na(+) channels associated with long QT syndrome 3 and Brugada syndrome. Front Physiol 2013; 4:153. [PMID: 23805106 PMCID: PMC3693076 DOI: 10.3389/fphys.2013.00153] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 06/10/2013] [Indexed: 11/21/2022] Open
Abstract
Mutations in SCN5A, the gene encoding the cardiac voltage-gated Na+ channel hNav1.5, can result in life-threatening arrhythmias including long QT syndrome 3 (LQT3) and Brugada syndrome (BrS). Numerous mutant hNav1.5 channels have been characterized upon heterologous expression and patch-clamp recordings during the last decade. These studies revealed functionally important regions in hNav1.5 and provided insight into gain-of-function or loss-of-function channel defects underlying LQT3 or BrS, respectively. The N-terminal region of hNav1.5, however, has not yet been investigated in detail, although several mutations were reported in the literature. In the present study we investigated three mutant channels, previously associated with LQT3 (G9V, R18W, V125L), and six mutant channels, associated with BrS (R18Q, R27H, G35S, V95I, R104Q, K126E). We applied both the two-microelectrode voltage clamp technique, using cRNA-injected Xenopus oocytes, and the whole-cell patch clamp technique using transfected HEK293 cells. Surprisingly, four out of the nine mutations did not affect channel properties. Gain-of-function, as typically observed in LQT3 mutant channels, was observed only in R18W and V125L, whereas loss-of-function, frequently found in BrS mutants, was found only in R27H, R104Q, and K126E. Our results indicate that the hNav1.5 N-terminus plays an important role for channel kinetics and stability. At the same time, we suggest that additional mechanisms, as e.g., disturbed interactions of the Na+ channel N-terminus with other proteins, contribute to severe clinical phenotypes.
Collapse
Affiliation(s)
- Christian Gütter
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University Jena Jena, Germany
| | | | | |
Collapse
|
40
|
Schwappacher R, Kilic A, Kojonazarov B, Lang M, Diep T, Zhuang S, Gawlowski T, Schermuly RT, Pfeifer A, Boss GR, Pilz RB. A molecular mechanism for therapeutic effects of cGMP-elevating agents in pulmonary arterial hypertension. J Biol Chem 2013; 288:16557-16566. [PMID: 23612967 DOI: 10.1074/jbc.m113.458729] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a progressive, usually fatal disease with abnormal vascular remodeling. Pulmonary artery smooth muscle cells (PASMCs) from PAH patients are hyperproliferative and apoptosis-resistant and demonstrate decreased signaling in response to bone morphogenetic proteins (BMPs). Cyclic GMP-elevating agents are beneficial in PAH, but their mechanism(s) of action are incompletely understood. Here we show that BMP signaling via Smad1/5/8 requires cGMP-dependent protein kinase isotype I (PKGI) to maintain PASMCs in a differentiated, low proliferative state. BMP cooperation with cGMP/PKGI was crucial for transcription of contractile genes and suppression of pro-proliferative and anti-apoptotic genes. Lungs from mice with low or absent PKGI (Prkg1(+/-) and Prkg1(-/-) mice) exhibited impaired BMP signaling, decreased contractile gene expression, and abnormal vascular remodeling. Conversely, cGMP stimulation of PKGI restored defective BMP signaling in rats with hypoxia-induced PAH, consistent with cGMP-elevating agents reversing vascular remodeling in this PAH model. Our results provide a mechanism for the therapeutic effects of cGMP-elevating agents in PAH and suggest that combining them with BMP mimetics may provide a novel, disease-modifying approach to PAH therapy.
Collapse
Affiliation(s)
- Raphaela Schwappacher
- Department of Medicine, University of California San Diego, La Jolla, California 92093.
| | - Ana Kilic
- Institute for Pharmacology and Toxicology, University of Bonn, 53113 Bonn, Germany
| | | | - Michaela Lang
- University of Giessen and Marburg Lung Center, 35392 Giessen, Germany
| | - Thuan Diep
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Shunhui Zhuang
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Thomas Gawlowski
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Ralph T Schermuly
- University of Giessen and Marburg Lung Center, 35392 Giessen, Germany
| | - Alexander Pfeifer
- Institute for Pharmacology and Toxicology, University of Bonn, 53113 Bonn, Germany
| | - Gerry R Boss
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Renate B Pilz
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| |
Collapse
|
41
|
Abstract
The abrupt cessation of effective cardiac function due to an aberrant heart rhythm can cause sudden and unexpected death at any age, a syndrome called sudden cardiac death (SCD). Annually, more than 300,000 cases of SCD occur in the United States alone, making this a major public health concern. Our current understanding of the mechanisms responsible for SCD has emerged from decades of basic science investigation into the normal electrophysiology of the heart, the molecular physiology of cardiac ion channels, fundamental cellular and tissue events associated with cardiac arrhythmias, and the molecular genetics of monogenic disorders of heart rhythm. This knowledge has helped shape the current diagnosis and treatment of inherited arrhythmia susceptibility syndromes associated with SCD and has provided a pathophysiological framework for understanding more complex conditions predisposing to this tragic event. This Review presents an overview of the molecular basis of SCD, with a focus on monogenic arrhythmia syndromes.
Collapse
Affiliation(s)
- Alfred L George
- Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA.
| |
Collapse
|
42
|
Shy D, Gillet L, Abriel H. Cardiac sodium channel NaV1.5 distribution in myocytes via interacting proteins: the multiple pool model. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:886-94. [PMID: 23123192 DOI: 10.1016/j.bbamcr.2012.10.026] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 11/16/2022]
Abstract
The cardiac sodium current (INa) is responsible for the rapid depolarization of cardiac cells, thus allowing for their contraction. It is also involved in regulating the duration of the cardiac action potential (AP) and propagation of the impulse throughout the myocardium. Cardiac INa is generated by the voltage-gated Na(+) channel, NaV1.5, a 2016-residue protein which forms the pore of the channel. Over the past years, hundreds of mutations in SCN5A, the human gene coding for NaV1.5, have been linked to many cardiac electrical disorders, including the congenital and acquired long QT syndrome, Brugada syndrome, conduction slowing, sick sinus syndrome, atrial fibrillation, and dilated cardiomyopathy. Similar to many membrane proteins, NaV1.5 has been found to be regulated by several interacting proteins. In some cases, these different proteins, which reside in distinct membrane compartments (i.e. lateral membrane vs. intercalated disks), have been shown to interact with the same regulatory domain of NaV1.5, thus suggesting that several pools of NaV1.5 channels may co-exist in cardiac cells. The aim of this review article is to summarize the recent works that demonstrate its interaction with regulatory proteins and illustrate the model that the sodium channel NaV1.5 resides in distinct and different pools in cardiac cells. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction.
Collapse
Affiliation(s)
- Diana Shy
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | | | | |
Collapse
|
43
|
Koval OM, Snyder JS, Wolf RM, Pavlovicz RE, Glynn P, Curran J, Leymaster ND, Dun W, Wright PJ, Cardona N, Qian L, Mitchell CC, Boyden PA, Binkley PF, Li C, Anderson ME, Mohler PJ, Hund TJ. Ca2+/calmodulin-dependent protein kinase II-based regulation of voltage-gated Na+ channel in cardiac disease. Circulation 2012; 126:2084-94. [PMID: 23008441 DOI: 10.1161/circulationaha.112.105320] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Human gene variants affecting ion channel biophysical activity and/or membrane localization are linked to potentially fatal cardiac arrhythmias. However, the mechanism for many human arrhythmia variants remains undefined despite more than a decade of investigation. Posttranslational modulation of membrane proteins is essential for normal cardiac function. Importantly, aberrant myocyte signaling has been linked to defects in cardiac ion channel posttranslational modifications and disease. We recently identified a novel pathway for posttranslational regulation of the primary cardiac voltage-gated Na(+) channel (Na(v)1.5) by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). However, a role for this pathway in cardiac disease has not been evaluated. METHODS AND RESULTS We evaluated the role of CaMKII-dependent phosphorylation in human genetic and acquired disease. We report an unexpected link between a short motif in the Na(v)1.5 DI-DII loop, recently shown to be critical for CaMKII-dependent phosphorylation, and Na(v)1.5 function in monogenic arrhythmia and common heart disease. Experiments in heterologous cells and primary ventricular cardiomyocytes demonstrate that the human arrhythmia susceptibility variants (A572D and Q573E) alter CaMKII-dependent regulation of Na(v)1.5, resulting in abnormal channel activity and cell excitability. In silico analysis reveals that these variants functionally mimic the phosphorylated channel, resulting in increased susceptibility to arrhythmia-triggering afterdepolarizations. Finally, we report that this same motif is aberrantly regulated in a large-animal model of acquired heart disease and in failing human myocardium. CONCLUSIONS We identify the mechanism for 2 human arrhythmia variants that affect Na(v)1.5 channel activity through direct effects on channel posttranslational modification. We propose that the CaMKII phosphorylation motif in the Na(v)1.5 DI-DII cytoplasmic loop is a critical nodal point for proarrhythmic changes to Na(v)1.5 in congenital and acquired cardiac disease.
Collapse
Affiliation(s)
- Olha M Koval
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, 473 W 12th Ave, Columbus, OH 43210, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Jeevaratnam K, Rewbury R, Zhang Y, Guzadhur L, Grace AA, Lei M, Huang CLH. Frequency distribution analysis of activation times and regional fibrosis in murine Scn5a+/- hearts: the effects of ageing and sex. Mech Ageing Dev 2012; 133:591-9. [PMID: 22968175 PMCID: PMC3466423 DOI: 10.1016/j.mad.2012.07.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 07/17/2012] [Accepted: 07/31/2012] [Indexed: 12/21/2022]
Abstract
Both Brugada Syndrome (BrS) and progressive cardiac conduction defect (PCCD) are associated respectively with diffuse and discrete alterations in conduction pathways affected by ageing and sex. This study assessed for contributions of such processes to the mechanism of conduction changes in Scn5a+/− and WT hearts stratified by age (3 and 12 months) and sex. In vivo electrocardiographic chest-lead assessment demonstrated greater incidences of bundle branch block in all Scn5a+/− mice compared to WT. Frequency analysis of right ventricular (RV) epicardial activation obtained from a 64-channel multi-electrode array demonstrated greater prominence of late conducting components in Scn5a+/− compared to WT male, and in male compared to female Scn5a+/− following stratification by genotype and sex. Similar differences were observed between old male Scn5a+/− and young male Scn5a+/−, old female Scn5a+/−, and old male WT, following stratification by genotype, age and sex. These findings directly correlated with histomorphometric assessment of regional fibrosis in both septa and free walls preferentially involving the RV. We demonstrate complex alterations in conduction distributions suggesting a conversion of normal to slow-conducting tissue, modulated by ageing and sex, coupled with fibrosis in Scn5a+/− hearts. These features suggest an overlap between pathophysiological processes related to BrS and PCCD in Scn5a+/− hearts.
Collapse
Affiliation(s)
- Kamalan Jeevaratnam
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
45
|
Huang CLH, Lei L, Matthews GDK, Zhang Y, Lei M. Pathophysiological Mechanisms of Sino-Atrial Dysfunction and Ventricular Conduction Disease Associated with SCN5A Deficiency: Insights from Mouse Models. Front Physiol 2012; 3:234. [PMID: 22783200 PMCID: PMC3390692 DOI: 10.3389/fphys.2012.00234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 06/11/2012] [Indexed: 11/13/2022] Open
Abstract
Genetically modified mice provide a number of models for studying cardiac channelopathies related to cardiac Na+ channel (SCN5A) abnormalities. We review key pathophysiological features in these murine models that may underlie clinical features observed in sinus node dysfunction and progressive cardiac conduction disease, thereby providing insights into their pathophysiological mechanisms. We describe loss of Na+ channel function and fibrotic changes associated with both loss and gain-of-function Na+ channel mutations. Recent reports further relate the progressive fibrotic changes to upregulation of TGF-β1 production and the transcription factors, Atf3, a stress-inducible gene, and Egr1, to the presence of heterozygous Scn5a gene deletion. Both changes are thus directly implicated in the clinically observed disruptions in sino-atrial node pacemaker function, and sino-atrial and ventricular conduction, and their progression with age. Murine systems with genetic modifications in Scn5a thus prove a useful tool to address questions concerning roles of genetic and environmental modifiers on human SCN5A disease phenotypes.
Collapse
Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory, Department of Biochemistry, University of Cambridge Cambridge, UK
| | | | | | | | | |
Collapse
|
46
|
Cerrone M, Noorman M, Lin X, Chkourko H, Liang FX, van der Nagel R, Hund T, Birchmeier W, Mohler P, van Veen TA, van Rijen HV, Delmar M. Sodium current deficit and arrhythmogenesis in a murine model of plakophilin-2 haploinsufficiency. Cardiovasc Res 2012; 95:460-8. [PMID: 22764151 DOI: 10.1093/cvr/cvs218] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
AIMS The shRNA-mediated loss of expression of the desmosomal protein plakophilin-2 leads to sodium current (I(Na)) dysfunction. Whether pkp2 gene haploinsufficiency leads to I(Na) deficit in vivo remains undefined. Mutations in pkp2 are detected in arrhythmogenic right ventricular cardiomyopathy (ARVC). Ventricular fibrillation and sudden death often occur in the 'concealed phase' of the disease, prior to overt structural damage. The mechanisms responsible for these arrhythmias remain poorly understood. We sought to characterize the morphology, histology, and ultrastructural features of PKP2-heterozygous-null (PKP2-Hz) murine hearts and explore the relation between PKP2 abundance, I(Na) function, and cardiac electrical synchrony. METHODS AND RESULTS Hearts of PKP2-Hz mice were characterized by multiple methods. We observed ultrastructural but not histological or gross anatomical differences in PKP2-Hz hearts compared with wild-type (WT) littermates. Yet, in myocytes, decreased amplitude and a shift in gating and kinetics of I(Na) were observed. To further unmask I(Na) deficiency, we exposed myocytes, Langendorff-perfused hearts, and anaesthetized animals to a pharmacological challenge (flecainide). In PKP2-Hz hearts, the extent of flecainide-induced I(Na) block, impaired ventricular conduction, and altered electrocardiographic parameters were larger than controls. Flecainide provoked ventricular arrhythmias and death in PKP2-Hz animals, but not in the WT. CONCLUSIONS PKP2 haploinsufficiency leads to I(Na) deficit in murine hearts. Our data support the notion of a cross-talk between desmosome and sodium channel complex. They also suggest that I(Na) dysfunction may contribute to generation and/or maintenance of arrhythmias in PKP2-deficient hearts. Whether pharmacological challenges could help unveil arrhythmia risk in patients with mutations or variants in PKP2 remains undefined.
Collapse
Affiliation(s)
- Marina Cerrone
- Division of Cardiology, New York University School of Medicine, New York, NY, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Arnolds DE, Liu F, Fahrenbach JP, Kim GH, Schillinger KJ, Smemo S, McNally EM, Nobrega MA, Patel VV, Moskowitz IP. TBX5 drives Scn5a expression to regulate cardiac conduction system function. J Clin Invest 2012; 122:2509-18. [PMID: 22728936 PMCID: PMC3386825 DOI: 10.1172/jci62617] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 05/17/2012] [Indexed: 11/17/2022] Open
Abstract
Cardiac conduction system (CCS) disease, which results in disrupted conduction and impaired cardiac rhythm, is common with significant morbidity and mortality. Current treatment options are limited, and rational efforts to develop cell-based and regenerative therapies require knowledge of the molecular networks that establish and maintain CCS function. Recent genome-wide association studies (GWAS) have identified numerous loci associated with adult human CCS function, including TBX5 and SCN5A. We hypothesized that TBX5, a critical developmental transcription factor, regulates transcriptional networks required for mature CCS function. We found that deletion of Tbx5 from the mature murine ventricular conduction system (VCS), including the AV bundle and bundle branches, resulted in severe VCS functional consequences, including loss of fast conduction, arrhythmias, and sudden death. Ventricular contractile function and the VCS fate map remained unchanged in VCS-specific Tbx5 knockouts. However, key mediators of fast conduction, including Nav1.5, which is encoded by Scn5a, and connexin 40 (Cx40), demonstrated Tbx5-dependent expression in the VCS. We identified a TBX5-responsive enhancer downstream of Scn5a sufficient to drive VCS expression in vivo, dependent on canonical T-box binding sites. Our results establish a direct molecular link between Tbx5 and Scn5a and elucidate a hierarchy between human GWAS loci that affects function of the mature VCS, establishing a paradigm for understanding the molecular pathology of CCS disease.
Collapse
Affiliation(s)
- David E Arnolds
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
|
49
|
Derangeon M, Montnach J, Baró I, Charpentier F. Mouse Models of SCN5A-Related Cardiac Arrhythmias. Front Physiol 2012; 3:210. [PMID: 22737129 PMCID: PMC3381239 DOI: 10.3389/fphys.2012.00210] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/29/2012] [Indexed: 12/19/2022] Open
Abstract
Mutations of SCN5A gene, which encodes the α-subunit of the voltage-gated Na+ channel NaV1.5, underlie hereditary cardiac arrhythmic syndromes such as the type 3 long QT syndrome, cardiac conduction diseases, the Brugada syndrome, the sick sinus syndrome, a trial standstill, and numerous overlap syndromes. Patch-clamp studies in heterologous expression systems have provided important information to understand the genotype-phenotype relationships of these diseases. However, they could not clarify how SCN5A mutations can be responsible for such a large spectrum of diseases, for the late age of onset or the progressiveness of some of these diseases and for the overlapping syndromes. Genetically modified mice rapidly appeared as promising tools for understanding the pathophysiological mechanisms of cardiac SCN5A-related arrhythmic syndromes and several mouse models have been established. This review presents the results obtained on these models that, for most of them, recapitulate the clinical phenotypes of the patients. This includes two models knocked out for Nav1.5 β1 and β3 auxiliary subunits that are also discussed. Despite their own limitations that we point out, the mouse models still appear as powerful tools to elucidate the pathophysiological mechanisms of SCN5A-related diseases and offer the opportunity to investigate the secondary cellular consequences of SCN5A mutations such as the expression remodeling of other genes. This points out the potential role of these genes in the overall human phenotype. Finally, they constitute useful tools for addressing the role of genetic and environmental modifiers on cardiac electrical activity.
Collapse
|
50
|
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.
Collapse
Affiliation(s)
- Claire A Martin
- Physiological Laboratory, University of Cambridge, Downing Site, Cambridge CB2 3EG, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|