1
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Aschner A, Keller A, Williams A, Whitney R, Cunningham K, Hamilton RM, Pollanen M, Donner E. Cardiac arrhythmia and epilepsy genetic variants in sudden unexpected death in epilepsy. Front Neurol 2024; 15:1386730. [PMID: 38756210 PMCID: PMC11097959 DOI: 10.3389/fneur.2024.1386730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 03/29/2024] [Indexed: 05/18/2024] Open
Abstract
Introduction Sudden Unexpected Death in Epilepsy (SUDEP) is the leading epilepsy-related cause of death, affecting approximately 1 per 1,000 individuals with epilepsy per year. Genetic variants that affect autonomic function, such as genes associated with cardiac arrhythmias, may predispose people with epilepsy to greater risk of both sudden cardiac death and SUDEP. Advances in next generation sequencing allow for the exploration of gene variants as potential biomarkers. Methods Genetic testing for the presence of cardiac arrhythmia and epilepsy gene variants was performed via genetic panels in 39 cases of SUDEP identified via autopsy by the Ontario Forensic Pathology Service. Variants were summarized by in-silico evidence for pathogenicity from 4 algorithms (SIFT, PolyPhen-2, PROVEAN, Mutation Taster) and allele frequencies in the general population (GnomAD). A maximum credible population allele frequency of 0.00004 was calculated based on epilepsy prevalence and SUDEP incidence to assess whether a variant was compatible with a pathogenic interpretation. Results Median age at the time of death was 33.3 years (range: 2, 60). Fifty-nine percent (n=23) were male. Gene panels detected 62 unique variants in 45 genes: 19 on the arrhythmia panel and 26 on the epilepsy panel. At least one variant was identified in 28 (72%) of decedents. Missense mutations comprised 57 (92%) of the observed variants. At least three in silico models predicted 12 (46%) cardiac arrhythmia panel missense variants and 20 (65%) epilepsy panel missense variants were pathogenic. Population allele frequencies were <0.00004 for 11 (42%) of the cardiac variants and 10 (32%) of the epilepsy variants. Together, these metrics identified 13 SUDEP variants of interest. Discussion Nearly three-quarters of decedents in this SUDEP cohort carried variants in comprehensive epilepsy or cardiac arrhythmia gene panels, with more than a third having variants in both panels. The proportion of decedents with cardiac variants aligns with recent studies of the disproportionate cardiac burden the epilepsy community faces compared to the general population and suggests a possible cardiac contribution to epilepsy mortality. These results identified 13 priority targets for future functional studies of these genes potential role in sudden death and demonstrates the necessity for further exploration of potential genetic contributions to SUDEP.
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Affiliation(s)
- Amir Aschner
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Anne Keller
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Andrew Williams
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Robyn Whitney
- McMaster Children’s Hospital, McMaster University, Hamilton, ON, Canada
| | - Kris Cunningham
- Department of Pathology and Molecular Medicine, School of Medicine, Faculty of Health Sciences, Queen’s University, Kingston, ON, Canada
| | - Robert M. Hamilton
- Division of Cardiology, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Michael Pollanen
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Elizabeth Donner
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Department of Pediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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2
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Nelson AD, Catalfio AM, Gupta JP, Min L, Caballero-Florán RN, Dean KP, Elvira CC, Derderian KD, Kyoung H, Sahagun A, Sanders SJ, Bender KJ, Jenkins PM. Physical and functional convergence of the autism risk genes Scn2a and Ank2 in neocortical pyramidal cell dendrites. Neuron 2024; 112:1133-1149.e6. [PMID: 38290518 PMCID: PMC11097922 DOI: 10.1016/j.neuron.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 04/26/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024]
Abstract
Dysfunction in sodium channels and their ankyrin scaffolding partners have both been implicated in neurodevelopmental disorders, including autism spectrum disorder (ASD). In particular, the genes SCN2A, which encodes the sodium channel NaV1.2, and ANK2, which encodes ankyrin-B, have strong ASD association. Recent studies indicate that ASD-associated haploinsufficiency in Scn2a impairs dendritic excitability and synaptic function in neocortical pyramidal cells, but how NaV1.2 is anchored within dendritic regions is unknown. Here, we show that ankyrin-B is essential for scaffolding NaV1.2 to the dendritic membrane of mouse neocortical neurons and that haploinsufficiency of Ank2 phenocopies intrinsic dendritic excitability and synaptic deficits observed in Scn2a+/- conditions. These results establish a direct, convergent link between two major ASD risk genes and reinforce an emerging framework suggesting that neocortical pyramidal cell dendritic dysfunction can contribute to neurodevelopmental disorder pathophysiology.
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Affiliation(s)
- Andrew D Nelson
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Amanda M Catalfio
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Julie P Gupta
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lia Min
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Kendall P Dean
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Carina C Elvira
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kimberly D Derderian
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Henry Kyoung
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Atehsa Sahagun
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Stephan J Sanders
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA
| | - Kevin J Bender
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA.
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Vătășescu RG, Paja CS, Șuș I, Cainap S, Moisa ȘM, Cinteză EE. Wolf-Parkinson-White Syndrome: Diagnosis, Risk Assessment, and Therapy-An Update. Diagnostics (Basel) 2024; 14:296. [PMID: 38337810 PMCID: PMC10855590 DOI: 10.3390/diagnostics14030296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Wolf-Parkinson-White (WPW) syndrome is a disorder characterized by the presence of at least one accessory pathway (AP) that can predispose people to atrial/ventricular tachyarrhythmias and even sudden cardiac death. It is the second most common cause of paroxysmal supraventricular tachycardia in most parts of the world, affecting about 0.1-0.3% of the general population. Most patients with WPW syndrome have normal anatomy, but it may be associated with concomitant congenital heart disease or systemic diseases. Although many individuals are asymptomatic, during supraventricular arrhythmia episodes, they may experience severe symptoms, including syncope or even sudden cardiac death (mainly due to pre-excited atrial fibrillation over rapidly conducting AP). In addition to arrhythmia-related symptoms, for some specific locations of the APs with overt anterograde conduction, there might be a reduction in exercise capacity mediated by a reduction in LV systolic performance due to anomalous LV depolarization. Although it is typically diagnosed through electrocardiography (ECG), additional tests are necessary for risk assessment. Management of WPW syndrome may be quite challenging and can vary from only acknowledging the presence of the accessory pathway to pharmacological treatment or radiofrequency ablation. Early diagnosis, risk assessment, and appropriate treatment are critical steps in the management of WPW syndrome, aiming to improve the quality of life and reduce the risk of life-threatening arrhythmias.
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Affiliation(s)
- Radu Gabriel Vătășescu
- Cardiology Department, Clinic Emergency Hospital, 014461 Bucharest, Romania;
- 4th Department—Cardio-Thoracic Pathology, University of Medicine and Pharmacy “Carol Davila”, 020021 Bucharest, Romania;
| | | | - Ioana Șuș
- Emergency Institute for Cardiovascular Disease and Transplantation, 540136 Tirgu Mures, Romania;
| | - Simona Cainap
- 8th Department—“Mother and Child”, University of Medicine and Pharmacy “Iuliu Hațieganu”, 400012 Cluj-Napoca, Romania;
- 2nd Pediatric Department, Clinical Children Hospital, 400177 Cluj-Napoca, Romania
| | - Ștefana María Moisa
- Department of Pediatrics, Faculty of Medicine, “Gr. T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- “Sfanta Maria” Clinical Emergency Hospital for Children, 700309 Iasi, Romania
| | - Eliza Elena Cinteză
- 4th Department—Cardio-Thoracic Pathology, University of Medicine and Pharmacy “Carol Davila”, 020021 Bucharest, Romania;
- Interventional Cardiology Compartment, Marie Sklodowska Curie Children Emergency Hospital, 077120 Bucharest, Romania
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Henriquez E, Hernandez EA, Mundla SR, Wankhade DH, Saad M, Ketha SS, Penke Y, Martinez GC, Ahmed FS, Hussain MS. Catecholaminergic Polymorphic Ventricular Tachycardia and Gene Therapy: A Comprehensive Review of the Literature. Cureus 2023; 15:e47974. [PMID: 38034271 PMCID: PMC10686237 DOI: 10.7759/cureus.47974] [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] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited channelopathy. In this review, we summarize the epidemiology, pathophysiology, clinical characteristics, diagnostics, genetic mutations, standard treatment, and the emergence of potential gene therapy. This inherited cardiac arrhythmia presents in a bimodal distribution with no association between sex or ethnicity. Six different CPVT genes have been identified, however, most of the cases are related to a heterozygous, gain-of-function mutation on the ryanodine receptor-2 gene (RyR2) and calsequestrin-2 gene (CASQ2) that causes delayed after-depolarization. The diagnosis is clinically based, seen in patients presenting with syncope after exercise or stress-related emotions, as well as cardiac arrest with full recovery or even sudden cardiac death. Standard treatment relies on beta-blockers, with add-on therapy, flecainide, and cardiac sympathetic denervation as second-line treatments. An implantable cardioverter-defibrillator is indicated for patients who have suffered a cardiac arrest. Potential gene therapy has emerged in the last 20 years and accelerated because of associated viral vector application in increasing the efficiency of prolonged cardiac gene expression. Nevertheless, human trials for gene therapy for CPVT have been limited as the population is rare, and an excessive amount of funding is required.
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Affiliation(s)
- Elvis Henriquez
- Miscellaneous, Facultad de Medicina, Universidad de Ciencias Medicas, Las Tunas, CUB
| | - Edwin A Hernandez
- Miscellaneous, Faculty of Medicine, Universidad de El Salvador, San Salvador, SLV
| | - Sravya R Mundla
- Internal Medicine, Apollo Institute of Medical Sciences and Research, Hyderabad, IND
| | | | - Muhammad Saad
- Internal Medicine, Fatima Memorial College (FMH) of Medicine and Dentistry, Lahore, PAK
| | - Sagar S Ketha
- Internal Medicine, Government Medical College, Srikakulam, IND
| | - Yasaswini Penke
- Internal Medicine, Government Medical College, Srikakulam, IND
| | - Gabriela C Martinez
- Internal Medicine, Faculty of Medicine, Universidad Nacional Autonoma de Honduras, San Pedro Sula, HND
| | - Faiza S Ahmed
- Internal Medicine, Advocate Lutheran General Hospital, Park Ridge, USA
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Gama M, Cardoso I, Palma Anselmo M, Aguiar Rosa S, Gaspar da Costa P, Fortuna P. Arrhythmogenic Left Ventricular Cardiomyopathy: A Successful Case of Extracorporeal Cardiopulmonary Resuscitation. ACTA MEDICA PORT 2023; 36:598-602. [PMID: 37658721 DOI: 10.20344/amp.19624] [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: 02/07/2023] [Accepted: 05/03/2023] [Indexed: 09/03/2023]
Abstract
A 24-year-old man suffered a witnessed cardiac arrest after a padel game. Basic life support was immediately provided. The pre-hospital emergency services team continued the resuscitation efforts, and the patient was accepted for extracorporeal cardiopulmonary resuscitation. The return of spontaneous circulation was achieved in 45 minutes. The initial assessment revealed a ST-segment elevation in leads V4-V6 and a dilated left ventricle with severe systolic dysfunction. Coronary angiography was normal. An improvement in left ventricular systolic function was observed and extracorporeal cardiac support was discontinued after 48 hours. Cardiovascular magnetic resonance imaging demonstrated hypokinesia and subepicardial fatty infiltration of the left ventricle lateral wall. Genetic testing detected a variant of uncertain significance in the ANK2 gene. The diagnosis of arrhythmogenic left ventricular myocardiopathy did not fulfill all the current diagnostic criteria, but it is a very likely diagnosis. An implantable cardioverter-defibrillator was placed. The patient was discharged without physical or cognitive impairment.
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Affiliation(s)
- Mafalda Gama
- Unidade de Urgência Médica. Centro Hospitalar Universitário de Lisboa Central. Lisbon. Portugal
| | - Isabel Cardoso
- Serviço de Cardiologia. Centro Hospitalar Universitário de Lisboa Central. Lisbon. Portugal
| | | | - Sílvia Aguiar Rosa
- Serviço de Cardiologia. Centro Hospitalar Universitário de Lisboa Central. Lisbon. Portugal
| | - Pedro Gaspar da Costa
- Unidade de Urgência Médica. Centro Hospitalar Universitário de Lisboa Central. Lisbon. Portugal
| | - Philip Fortuna
- Unidade de Urgência Médica. Centro Hospitalar Universitário de Lisboa Central. Lisbon. Portugal
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Sinus node dysfunction and atrial fibrillation-Relationships, clinical phenotypes, new mechanisms, and treatment approaches. Ageing Res Rev 2023; 86:101890. [PMID: 36813137 DOI: 10.1016/j.arr.2023.101890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023]
Abstract
Although the anatomical basis of the pathogenesis of sinus node dysfunction (SND) and atrial fibrillation (AF) is located primarily in the left and right atria, increasing evidence suggests a strong correlation between SND and AF, in terms of both clinical presentation and formation mechanisms. However, the exact mechanisms underlying this association are unclear. The relationship between SND and AF may not be causal, but is likely to involve common factors and mechanisms, including ion channel remodeling, gap junction abnormalities, structural remodeling, genetic mutations, neuromodulation abnormalities, the effects of adenosine on cardiomyocytes, oxidative stress, and viral infections. Ion channel remodeling manifests primarily as alterations in the "funny" current (If) and Ca2+ clock associated with cardiomyocyte autoregulation, and gap junction abnormalities are manifested primarily as decreased expression of connexins (Cxs) mediating electrical impulse propagation in cardiomyocytes. Structural remodeling refers primarily to fibrosis and cardiac amyloidosis (CA). Some genetic mutations can also cause arrhythmias, such as SCN5A, HCN4, EMD, and PITX2. The intrinsic cardiac autonomic nervous system (ICANS), a regulator of the heart's physiological functions, triggers arrhythmias.In addition, we discuss arrhythmias caused by viral infections, notably Coronavirus Disease 2019 (COVID-19). Similarly to upstream treatments for atrial cardiomyopathy such as alleviating CA, ganglionated plexus (GP) ablation acts on the common mechanisms between SND and AF, thus achieving a dual therapeutic effect.
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7
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Calcium Handling in Inherited Cardiac Diseases: A Focus on Catecholaminergic Polymorphic Ventricular Tachycardia and Hypertrophic Cardiomyopathy. Int J Mol Sci 2023; 24:ijms24043365. [PMID: 36834774 PMCID: PMC9963263 DOI: 10.3390/ijms24043365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/02/2023] [Accepted: 02/04/2023] [Indexed: 02/10/2023] Open
Abstract
Calcium (Ca2+) is the major mediator of cardiac contractile function. It plays a key role in regulating excitation-contraction coupling and modulating the systolic and diastolic phases. Defective handling of intracellular Ca2+ can cause different types of cardiac dysfunction. Thus, the remodeling of Ca2+ handling has been proposed to be a part of the pathological mechanism leading to electrical and structural heart diseases. Indeed, to ensure appropriate electrical cardiac conduction and contraction, Ca2+ levels are regulated by several Ca2+-related proteins. This review focuses on the genetic etiology of cardiac diseases related to calcium mishandling. We will approach the subject by focalizing on two clinical entities: catecholaminergic polymorphic ventricular tachycardia (CPVT) as a cardiac channelopathy and hypertrophic cardiomyopathy (HCM) as a primary cardiomyopathy. Further, this review will illustrate the fact that despite the genetic and allelic heterogeneity of cardiac defects, calcium-handling perturbations are the common pathophysiological mechanism. The newly identified calcium-related genes and the genetic overlap between the associated heart diseases are also discussed in this review.
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8
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Global profiling of AMG510 modified proteins identified tumor suppressor KEAP1 as an off-target. iScience 2023; 26:106080. [PMID: 36824285 PMCID: PMC9942120 DOI: 10.1016/j.isci.2023.106080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/30/2022] [Accepted: 01/23/2023] [Indexed: 01/30/2023] Open
Abstract
KRAS inhibitor AMG510 covalently modifies the G12C residue and inactivates the KRAS/G12C function. Because there are many reactive cysteines in the proteome, it is important to characterize AMG510 on-target modification and off-targets. Here, we presented a streamlined workflow to measure abundant AMG510 modified peptides including that of KRAS/G12C by direct profiling, and a pan-AMG510 antibody peptide IP workflow to profile less abundant AMG510 off-targets. We identified over 300 off-target sites with three distinct kinetic patterns, expanding the AMG510 modified proteome involved in the nucleocytoplasmic transport, response to oxidative stress, adaptive immune system, and glycolysis. We found that AMG510 covalently modified cys339 of ALDOA and inhibited its enzyme activity. Moreover, AMG510 modified KEAP1 cys288 and induced NRF2 accumulation in the nuclear of NSCLC cells independent of KRAS/G12C mutation. Our study provides a comprehensive resource of protein off-targets of AMG510 and elucidates potential toxicological sideeffects for this covalent KRASG12C inhibitor.
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9
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Precision medicine for long QT syndrome: patient-specific iPSCs take the lead. Expert Rev Mol Med 2023; 25:e5. [PMID: 36597672 DOI: 10.1017/erm.2022.43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Long QT syndrome (LQTS) is a detrimental arrhythmia syndrome mainly caused by dysregulated expression or aberrant function of ion channels. The major clinical symptoms of ventricular arrhythmia, palpitations and syncope vary among LQTS subtypes. Susceptibility to malignant arrhythmia is a result of delayed repolarisation of the cardiomyocyte action potential (AP). There are 17 distinct subtypes of LQTS linked to 15 autosomal dominant genes with monogenic mutations. However, due to the presence of modifier genes, the identical mutation may result in completely different clinical manifestations in different carriers. In this review, we describe the roles of various ion channels in orchestrating APs and discuss molecular aetiologies of various types of LQTS. We highlight the usage of patient-specific induced pluripotent stem cell (iPSC) models in characterising fundamental mechanisms associated with LQTS. To mitigate the outcomes of LQTS, treatment strategies are initially focused on small molecules targeting ion channel activities. Next-generation treatments will reap the benefits from development of LQTS patient-specific iPSC platform, which is bolstered by the state-of-the-art technologies including whole-genome sequencing, CRISPR genome editing and machine learning. Deep phenotyping and high-throughput drug testing using LQTS patient-specific cardiomyocytes herald the upcoming precision medicine in LQTS.
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10
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Keefe JA, Moore OM, Ho KS, Wehrens XHT. Role of Ca 2+ in healthy and pathologic cardiac function: from normal excitation-contraction coupling to mutations that cause inherited arrhythmia. Arch Toxicol 2023; 97:73-92. [PMID: 36214829 PMCID: PMC10122835 DOI: 10.1007/s00204-022-03385-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/15/2022] [Indexed: 01/19/2023]
Abstract
Calcium (Ca2+) ions are a key second messenger involved in the rhythmic excitation and contraction of cardiomyocytes throughout the heart. Proper function of Ca2+-handling proteins is required for healthy cardiac function, whereas disruption in any of these can cause cardiac arrhythmias. This comprehensive review provides a broad overview of the roles of Ca2+-handling proteins and their regulators in healthy cardiac function and the mechanisms by which mutations in these proteins contribute to inherited arrhythmias. Major Ca2+ channels and Ca2+-sensitive regulatory proteins involved in cardiac excitation-contraction coupling are discussed, with special emphasis on the function of the RyR2 macromolecular complex. Inherited arrhythmia disorders including catecholaminergic polymorphic ventricular tachycardia, long QT syndrome, Brugada syndrome, short QT syndrome, and arrhythmogenic right-ventricular cardiomyopathy are discussed with particular emphasis on subtypes caused by mutations in Ca2+-handling proteins.
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Affiliation(s)
- Joshua A Keefe
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Oliver M Moore
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kevin S Ho
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA. .,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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11
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Jeong HK, Kim SS, Kim HK, Ki YJ, Park KH, Choi DH. A case of sinus arrest in atrial fibrillation with pulmonary embolism after flecainide ingestion. Transl Clin Pharmacol 2022; 30:182-186. [PMID: 36632074 PMCID: PMC9810487 DOI: 10.12793/tcp.2022.30.e19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/05/2022] [Accepted: 11/03/2022] [Indexed: 12/31/2022] Open
Abstract
A 76-year-old female visited the emergency department with complaining of dizziness and syncope. She had a history of paroxysmal atrial fibrillation (AF) and had been prescribed flecainide 50 mg and apixaban 5 mg 12-hourly in another hospital 1 day before the presentation. Upon admission, her electrocardiogram showed profound bradycardia and extremely long sinus arrest, which required temporary cardiac pacing. Within 24 hours, her intrinsic rhythm was restored, and the temporary pacemaker was removed. Transthoracic and transesophageal echocardiography revealed no structural heart disease or thrombus in the left atrial appendage. Cardiac computed tomography showed no coronary artery stenosis, but a pulmonary thrombus in the right pulmonary artery. She underwent an electrophysiology study, and four pulmonary vein (PV) isolations were attempted to treat the paroxysmal AF. A bidirectional PV conduction block was acquired in all PVs despite spontaneous dissociation of PV potential in the right PV. Programmed stimulation following ablation resulted in sinus node dysfunction. After the procedure, the patient did not complain of dizziness and syncope for 72 hours of telemetry monitoring. She was discharged with anticoagulant and did not show any further symptoms for 6 months. Flecainide acetate is a class Ic antiarrhythmics, and its clinical efficacy has been confirmed in several clinical trials. However, it can unmask sinus node dysfunction in asymptomatic patients with paroxysmal AF. Clinicians should screen candidates for sinus nodal diseases when prescribing flecainide.
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Affiliation(s)
- Hyung Ki Jeong
- Department of Cardiovascular Medicine, Wonkwang University Medical School, Iksan 54538, Korea
| | - Sung Soo Kim
- Department of Cardiovascular Medicine, Chosun University Medical School, Gwangju 61452, Korea
| | - Hyun Kuk Kim
- Department of Cardiovascular Medicine, Chosun University Medical School, Gwangju 61452, Korea
| | - Young Jae Ki
- Department of Cardiovascular Medicine, Chosun University Medical School, Gwangju 61452, Korea
| | - Keun Ho Park
- Department of Cardiovascular Medicine, Chosun University Medical School, Gwangju 61452, Korea
| | - Dong Hyun Choi
- Department of Cardiovascular Medicine, Chosun University Medical School, Gwangju 61452, Korea
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Postrigan AE, Babushkina NP, Svintsova LI, Plotnikova IV, Skryabin NA. Clinical and Genetic Characteristics of Congenital Long QT Syndrome. RUSS J GENET+ 2022. [DOI: 10.1134/s1022795422100064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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13
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York NS, Sanchez-Arias JC, McAdam ACH, Rivera JE, Arbour LT, Swayne LA. Mechanisms underlying the role of ankyrin-B in cardiac and neurological health and disease. Front Cardiovasc Med 2022; 9:964675. [PMID: 35990955 PMCID: PMC9386378 DOI: 10.3389/fcvm.2022.964675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
The ANK2 gene encodes for ankyrin-B (ANKB), one of 3 members of the ankyrin family of proteins, whose name is derived from the Greek word for anchor. ANKB was originally identified in the brain (B denotes “brain”) but has become most widely known for its role in cardiomyocytes as a scaffolding protein for ion channels and transporters, as well as an interacting protein for structural and signaling proteins. Certain loss-of-function ANK2 variants are associated with a primarily cardiac-presenting autosomal-dominant condition with incomplete penetrance and variable expressivity characterized by a predisposition to supraventricular and ventricular arrhythmias, arrhythmogenic cardiomyopathy, congenital and adult-onset structural heart disease, and sudden death. Another independent group of ANK2 variants are associated with increased risk for distinct neurological phenotypes, including epilepsy and autism spectrum disorders. The mechanisms underlying ANKB's roles in cells in health and disease are not fully understood; however, several clues from a range of molecular and cell biological studies have emerged. Notably, ANKB exhibits several isoforms that have different cell-type–, tissue–, and developmental stage– expression profiles. Given the conservation within ankyrins across evolution, model organism studies have enabled the discovery of several ankyrin roles that could shed important light on ANKB protein-protein interactions in heart and brain cells related to the regulation of cellular polarity, organization, calcium homeostasis, and glucose and fat metabolism. Along with this accumulation of evidence suggesting a diversity of important ANKB cellular functions, there is an on-going debate on the role of ANKB in disease. We currently have limited understanding of how these cellular functions link to disease risk. To this end, this review will examine evidence for the cellular roles of ANKB and the potential contribution of ANKB functional variants to disease risk and presentation. This contribution will highlight the impact of ANKB dysfunction on cardiac and neuronal cells and the significance of understanding the role of ANKB variants in disease.
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Affiliation(s)
- Nicole S. York
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | | | - Alexa C. H. McAdam
- Department of Medical Genetics, University of British Columbia, Victoria, BC, Canada
| | - Joel E. Rivera
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Laura T. Arbour
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Medical Genetics, University of British Columbia, Victoria, BC, Canada
- *Correspondence: Laura T. Arbour
| | - Leigh Anne Swayne
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Cellular and Physiological Sciences and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Leigh Anne Swayne
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14
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Skogestad J, Aronsen JM. Regulation of Cardiac Contractility by the Alpha 2 Subunit of the Na+/K+-ATPase. Front Physiol 2022; 13:827334. [PMID: 35812308 PMCID: PMC9258780 DOI: 10.3389/fphys.2022.827334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/16/2022] [Indexed: 11/14/2022] Open
Abstract
Cytosolic Na + concentrations regulate cardiac excitation-contraction coupling and contractility. Inhibition of the Na+/K+-ATPase (NKA) activity increases cardiac contractility by increasing cytosolic Ca2+ levels, as increased cytosolic Na+ levels are coupled to less Ca2+ extrusion and/or increased Ca2+ influx from the Na+/Ca2+-exchanger. NKA consists of one α subunit and one β subunit, with α1 and α2 being the main α isoforms in cardiomyocytes. Substantial evidence suggests that NKAα2 is the primary regulator of cardiac contractility despite being outnumbered by NKAα1 in cardiomyocytes. This review will mainly focus on differential regulation and subcellular localization of the NKAα1 and NKAα2 isoforms, and their relation to the proposed concept of subcellular gradients of Na+ in cardiomyocytes. We will also discuss the potential roles of NKAα2 in mediating cardiac hypertrophy and ventricular arrhythmias.
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Affiliation(s)
- Jonas Skogestad
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Jan Magnus Aronsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
- *Correspondence: Jan Magnus Aronsen,
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15
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Gao Y, Wu D, Chen B, Chen Y, Zhang Q, Zhao P. Rare Variants in Novel Candidate Genes Associated With Nonsyndromic Patent Ductus Arteriosus Identified With Whole-Exome Sequencing. Front Genet 2022; 13:921925. [PMID: 35734438 PMCID: PMC9207465 DOI: 10.3389/fgene.2022.921925] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 05/09/2022] [Indexed: 11/18/2022] Open
Abstract
Background: Patent ductus arteriosus (PDA) is one of the most common congenital heart defects causing pulmonary hypertension, infective endocarditis, and even death. The important role of genetics in determining spontaneous ductal closure has been well-established. However, as many of the identified variants are rare, thorough identification of the associated genetic factors is necessary to further explore the genetic etiology of PDA. Methods: We performed whole-exome sequencing (WES) on 39 isolated nonsyndromic PDA patients and 100 healthy controls. Rare variants and novel genes were identified through bioinformatic filtering strategies. The expression patterns of candidate genes were explored in human embryo heart samples. Results: Eighteen rare damaging variants of six novel PDA-associated genes (SOX8, NES, CDH2, ANK3, EIF4G1, and HIPK1) were newly identified, which were highly expressed in human embryo hearts. Conclusions: WES is an efficient diagnostic tool for exploring the genetic pathogenesis of PDA. These findings contribute new insights into the molecular basis of PDA and may inform further studies on genetic risk factors for congenital heart defects.
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Affiliation(s)
- Ying Gao
- Department of Pediatric, Shidong Hospital, Shanghai, China
| | - Dan Wu
- Department of Pediatric, Shidong Hospital, Shanghai, China
| | - Bo Chen
- Department of Cardiothoracic Surgery, School of Medicine, Heart Center, Shanghai Children’s Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yinghui Chen
- Department of Pediatric Cardiology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Qi Zhang
- Department of Pediatric Cardiology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Pengjun Zhao
- Department of Pediatric Cardiology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Pengjun Zhao,
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16
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Walsh R, Adler A, Amin AS, Abiusi E, Care M, Bikker H, Amenta S, Feilotter H, Nannenberg EA, Mazzarotto F, Trevisan V, Garcia J, Hershberger RE, Perez MV, Sturm AC, Ware JS, Zareba W, Novelli V, Wilde AAM, Gollob MH. Evaluation of gene validity for CPVT and short QT syndrome in sudden arrhythmic death. Eur Heart J 2022; 43:1500-1510. [PMID: 34557911 PMCID: PMC9009401 DOI: 10.1093/eurheartj/ehab687] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/11/2021] [Accepted: 09/09/2021] [Indexed: 12/02/2022] Open
Abstract
AIMS Catecholaminergic polymorphic ventricular tachycardia (CPVT) and short QT syndrome (SQTS) are inherited arrhythmogenic disorders that can cause sudden death. Numerous genes have been reported to cause these conditions, but evidence supporting these gene-disease relationships varies considerably. To ensure appropriate utilization of genetic information for CPVT and SQTS patients, we applied an evidence-based reappraisal of previously reported genes. METHODS AND RESULTS Three teams independently curated all published evidence for 11 CPVT and 9 SQTS implicated genes using the ClinGen gene curation framework. The results were reviewed by a Channelopathy Expert Panel who provided the final classifications. Seven genes had definitive to moderate evidence for disease causation in CPVT, with either autosomal dominant (RYR2, CALM1, CALM2, CALM3) or autosomal recessive (CASQ2, TRDN, TECRL) inheritance. Three of the four disputed genes for CPVT (KCNJ2, PKP2, SCN5A) were deemed by the Expert Panel to be reported for phenotypes that were not representative of CPVT, while reported variants in a fourth gene (ANK2) were too common in the population to be disease-causing. For SQTS, only one gene (KCNH2) was classified as definitive, with three others (KCNQ1, KCNJ2, SLC4A3) having strong to moderate evidence. The majority of genetic evidence for SQTS genes was derived from very few variants (five in KCNJ2, two in KCNH2, one in KCNQ1/SLC4A3). CONCLUSIONS Seven CPVT and four SQTS genes have valid evidence for disease causation and should be included in genetic testing panels. Additional genes associated with conditions that may mimic clinical features of CPVT/SQTS have potential utility for differential diagnosis.
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Affiliation(s)
- Roddy Walsh
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Arnon Adler
- Division of Cardiology, Department of Medicine, Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Avenue, Toronto, ON M5G 2N2, Canada
| | - Ahmad S Amin
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Emanuela Abiusi
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - Melanie Care
- Division of Cardiology, Toronto General Hospital, The Toronto General Hospital Research Institute, University Health Network, University of Toronto, 200 Elizabeth St, Toronto, ON M5G 2C4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Cir, Toronto, ON M5S 1A8, Canada
| | - Hennie Bikker
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Simona Amenta
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - Harriet Feilotter
- Department of Pathology and Molecular Medicine, Queen's University, 88 Stuart Street, Kingston, ON K7L 3N6, Canada
| | - Eline A Nannenberg
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Francesco Mazzarotto
- Department of Experimental and Clinical Medicine, University of Florence, Viale Pieraccini 6, Florence 50139, Italy
- Faculty of Medicine, National Heart & Lung Institute, Imperial College London, Dovehouse St, London SW3 6LY, UK
- Cardiovascular Research Centre, Royal Brompton & Harefield Hospitals, Sydney St, London SW3 6NP, UK
| | - Valentina Trevisan
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - John Garcia
- Invitae Corp., 1400 16th St, San Francisco, CA 94103, USA
| | - Ray E Hershberger
- Division of Human Genetics, Department of Internal Medicine, The Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, 473 W 12th Ave, Columbus, OH 43210, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, 473 W 12th Ave, Columbus, OH 43210, USA
| | - Marco V Perez
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, 300 Pasteur Dr, Stanford, CA 94305, USA
| | - Amy C Sturm
- Geisinger Genomic Medicine Institute, 100 N Academy Ave, Danville, PA 17822, USA
| | - James S Ware
- Faculty of Medicine, National Heart & Lung Institute, Imperial College London, Dovehouse St, London SW3 6LY, UK
- Cardiovascular Research Centre, Royal Brompton & Harefield Hospitals, Sydney St, London SW3 6NP, UK
- Cardiovascular Genomics and Precision Medicine, MRC London Institute of Medical Sciences, Imperial College London, Du Cane Rd, London W12 0NN, UK
| | - Wojciech Zareba
- Cardiology Unit of the Department of Medicine, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Valeria Novelli
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Michael H Gollob
- Division of Cardiology, Toronto General Hospital, The Toronto General Hospital Research Institute, University Health Network, University of Toronto, 200 Elizabeth St, Toronto, ON M5G 2C4, Canada
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17
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Daimi H, Lozano-Velasco E, Aranega A, Franco D. Genomic and Non-Genomic Regulatory Mechanisms of the Cardiac Sodium Channel in Cardiac Arrhythmias. Int J Mol Sci 2022; 23:1381. [PMID: 35163304 PMCID: PMC8835759 DOI: 10.3390/ijms23031381] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/30/2021] [Accepted: 01/06/2022] [Indexed: 12/19/2022] Open
Abstract
Nav1.5 is the predominant cardiac sodium channel subtype, encoded by the SCN5A gene, which is involved in the initiation and conduction of action potentials throughout the heart. Along its biosynthesis process, Nav1.5 undergoes strict genomic and non-genomic regulatory and quality control steps that allow only newly synthesized channels to reach their final membrane destination and carry out their electrophysiological role. These regulatory pathways are ensured by distinct interacting proteins that accompany the nascent Nav1.5 protein along with different subcellular organelles. Defects on a large number of these pathways have a tremendous impact on Nav1.5 functionality and are thus intimately linked to cardiac arrhythmias. In the present review, we provide current state-of-the-art information on the molecular events that regulate SCN5A/Nav1.5 and the cardiac channelopathies associated with defects in these pathways.
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Affiliation(s)
- Houria Daimi
- Biochemistry and Molecular Biology Laboratory, Faculty of Pharmacy, University of Monastir, Monastir 5000, Tunisia
| | - Estefanía Lozano-Velasco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Amelia Aranega
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Diego Franco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
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18
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Martínez-Barrios E, Cesar S, Cruzalegui J, Hernandez C, Arbelo E, Fiol V, Brugada J, Brugada R, Campuzano O, Sarquella-Brugada G. Clinical Genetics of Inherited Arrhythmogenic Disease in the Pediatric Population. Biomedicines 2022; 10:106. [PMID: 35052786 PMCID: PMC8773373 DOI: 10.3390/biomedicines10010106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/27/2021] [Accepted: 12/31/2021] [Indexed: 12/19/2022] Open
Abstract
Sudden death is a rare event in the pediatric population but with a social shock due to its presentation as the first symptom in previously healthy children. Comprehensive autopsy in pediatric cases identify an inconclusive cause in 40-50% of cases. In such cases, a diagnosis of sudden arrhythmic death syndrome is suggested as the main potential cause of death. Molecular autopsy identifies nearly 30% of cases under 16 years of age carrying a pathogenic/potentially pathogenic alteration in genes associated with any inherited arrhythmogenic disease. In the last few years, despite the increasing rate of post-mortem genetic diagnosis, many families still remain without a conclusive genetic cause of the unexpected death. Current challenges in genetic diagnosis are the establishment of a correct genotype-phenotype association between genes and inherited arrhythmogenic disease, as well as the classification of variants of uncertain significance. In this review, we provide an update on the state of the art in the genetic diagnosis of inherited arrhythmogenic disease in the pediatric population. We focus on emerging publications on gene curation for genotype-phenotype associations, cases of genetic overlap and advances in the classification of variants of uncertain significance. Our goal is to facilitate the translation of genetic diagnosis to the clinical area, helping risk stratification, treatment and the genetic counselling of families.
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Affiliation(s)
- Estefanía Martínez-Barrios
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Sergi Cesar
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - José Cruzalegui
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Clara Hernandez
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Elena Arbelo
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Victoria Fiol
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Josep Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Ramon Brugada
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain
| | - Oscar Campuzano
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Georgia Sarquella-Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
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19
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Sergienko NM, Donner DG, Delbridge LMD, McMullen JR, Weeks KL. Protein phosphatase 2A in the healthy and failing heart: New insights and therapeutic opportunities. Cell Signal 2021; 91:110213. [PMID: 34902541 DOI: 10.1016/j.cellsig.2021.110213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 12/02/2021] [Accepted: 12/07/2021] [Indexed: 02/06/2023]
Abstract
Protein phosphatases have emerged as critical regulators of phosphoprotein homeostasis in settings of health and disease. Protein phosphatase 2A (PP2A) encompasses a large subfamily of enzymes that remove phosphate groups from serine/threonine residues within phosphoproteins. The heterogeneity in PP2A structure, which arises from the grouping of different catalytic, scaffolding and regulatory subunit isoforms, creates distinct populations of catalytically active enzymes (i.e. holoenzymes) that localise to different parts of the cell. This structural complexity, combined with other regulatory mechanisms, such as interaction of PP2A heterotrimers with accessory proteins and post-translational modification of the catalytic and/or regulatory subunits, enables PP2A holoenzymes to target phosphoprotein substrates in a highly specific manner. In this review, we summarise the roles of PP2A in cardiac physiology and disease. PP2A modulates numerous processes that are vital for heart function including calcium handling, contractility, β-adrenergic signalling, metabolism and transcription. Dysregulation of PP2A has been observed in human cardiac disease settings, including heart failure and atrial fibrillation. Efforts are underway, particularly in the cancer field, to develop therapeutics targeting PP2A activity. The development of small molecule activators of PP2A (SMAPs) and other compounds that selectively target specific PP2A holoenzymes (e.g. PP2A/B56α and PP2A/B56ε) will improve understanding of the function of different PP2A species in the heart, and may lead to the development of therapeutics for normalising aberrant protein phosphorylation in settings of cardiac remodelling and dysfunction.
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Affiliation(s)
- Nicola M Sergienko
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Central Clinical School, Monash University, Clayton VIC 3800, Australia
| | - Daniel G Donner
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Baker Department of Cardiometabolic Health, The University of Melbourne, Parkville VIC 3010, Australia
| | - Lea M D Delbridge
- Department of Anatomy and Physiology, The University of Melbourne, Parkville VIC 3010, Australia
| | - Julie R McMullen
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Baker Department of Cardiometabolic Health, The University of Melbourne, Parkville VIC 3010, Australia; Department of Physiology and Department of Medicine Alfred Hospital, Monash University, Clayton VIC 3800, Australia; Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora VIC 3086, Australia; Department of Diabetes, Central Clinical School, Monash University, Clayton VIC 3800, Australia.
| | - Kate L Weeks
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Department of Anatomy and Physiology, The University of Melbourne, Parkville VIC 3010, Australia; Baker Department of Cardiometabolic Health, The University of Melbourne, Parkville VIC 3010, Australia; Department of Diabetes, Central Clinical School, Monash University, Clayton VIC 3800, Australia.
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20
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Sleiman Y, Lacampagne A, Meli AC. "Ryanopathies" and RyR2 dysfunctions: can we further decipher them using in vitro human disease models? Cell Death Dis 2021; 12:1041. [PMID: 34725342 PMCID: PMC8560800 DOI: 10.1038/s41419-021-04337-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/08/2021] [Accepted: 10/14/2021] [Indexed: 12/23/2022]
Abstract
The regulation of intracellular calcium (Ca2+) homeostasis is fundamental to maintain normal functions in many cell types. The ryanodine receptor (RyR), the largest intracellular calcium release channel located on the sarco/endoplasmic reticulum (SR/ER), plays a key role in the intracellular Ca2+ handling. Abnormal type 2 ryanodine receptor (RyR2) function, associated to mutations (ryanopathies) or pathological remodeling, has been reported, not only in cardiac diseases, but also in neuronal and pancreatic disorders. While animal models and in vitro studies provided valuable contributions to our knowledge on RyR2 dysfunctions, the human cell models derived from patients’ cells offer new hope for improving our understanding of human clinical diseases and enrich the development of great medical advances. We here discuss the current knowledge on RyR2 dysfunctions associated with mutations and post-translational remodeling. We then reviewed the novel human cellular technologies allowing the correlation of patient’s genome with their cellular environment and providing approaches for personalized RyR-targeted therapeutics.
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Affiliation(s)
- Yvonne Sleiman
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Alain Lacampagne
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Albano C Meli
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France.
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21
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Blandin CE, Gravez BJ, Hatem SN, Balse E. Remodeling of Ion Channel Trafficking and Cardiac Arrhythmias. Cells 2021; 10:cells10092417. [PMID: 34572065 PMCID: PMC8468138 DOI: 10.3390/cells10092417] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 01/08/2023] Open
Abstract
Both inherited and acquired cardiac arrhythmias are often associated with the abnormal functional expression of ion channels at the cellular level. The complex machinery that continuously traffics, anchors, organizes, and recycles ion channels at the plasma membrane of a cardiomyocyte appears to be a major source of channel dysfunction during cardiac arrhythmias. This has been well established with the discovery of mutations in the genes encoding several ion channels and ion channel partners during inherited cardiac arrhythmias. Fibrosis, altered myocyte contacts, and post-transcriptional protein changes are common factors that disorganize normal channel trafficking during acquired cardiac arrhythmias. Channel availability, described notably for hERG and KV1.5 channels, could be another potent arrhythmogenic mechanism. From this molecular knowledge on cardiac arrhythmias will emerge novel antiarrhythmic strategies.
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Affiliation(s)
- Camille E. Blandin
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
| | - Basile J. Gravez
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
| | - Stéphane N. Hatem
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
- ICAN—Institute of Cardiometabolism and Nutrition, Institute of Cardiology, Pitié-Salpêtrière Hospital, Sorbonne University, F-75013 Paris, France
| | - Elise Balse
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
- Correspondence:
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22
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Song J, Luo Y, Jiang Y, He J. Advances in the Molecular Genetics of Catecholaminergic Polymorphic Ventricular Tachycardia. Front Pharmacol 2021; 12:718208. [PMID: 34483927 PMCID: PMC8415552 DOI: 10.3389/fphar.2021.718208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/05/2021] [Indexed: 11/13/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia is a primary arrhythmogenic syndrome with genetic features most commonly seen in adolescents, with syncope and sudden death following exercise or agitation as the main clinical manifestations. The mechanism of its occurrence is related to the aberrant release of Ca2+ from cardiomyocytes caused by abnormal RyR2 channels or CASQ2 proteins under conditions of sympathetic excitation, thus inducing a delayed posterior exertional pole, manifested by sympathetic excitation inducing adrenaline secretion, resulting in bidirectional or polymorphic ventricular tachycardia. The mortality rate of the disease is high, but patients usually do not have organic heart disease, the clinical manifestations may not be obvious, and no significant abnormal changes in the QT interval are often observed on electrocardiography. Therefore, the disease is often easily missed and misdiagnosed. A number of genetic mutations have been linked to the development of this disease, and the mechanisms are different. In this paper, we would like to summarize the possible genes related to catecholaminergic polymorphic ventricular tachycardia in order to review the genetic tests currently performed, and to further promote the development of genetic testing techniques and deepen the research on the molecular level of this disease.
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Affiliation(s)
- Junxia Song
- Departments of Cardiology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Yanhong Luo
- Endocrinology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Ying Jiang
- Departments of Cardiology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Jianfeng He
- Departments of Cardiology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
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The rs45454496 (E1813K) variant in the adiposity gene ANK2 doesn't associate with obesity in Southern European subjects. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Steinfurt J, Bezzina CR, Biermann J, Staudacher D, Marschall C, Trolese L, Faber TS, Duerschmied D, Zehender M, Bode C, Wilde AAM, Odening KE, Lodder EM. Two siblings with early repolarization syndrome: clinical and genetic characterization by whole-exome sequencing. Europace 2021; 23:775-780. [PMID: 33324992 PMCID: PMC8139820 DOI: 10.1093/europace/euaa357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/10/2020] [Indexed: 01/23/2023] Open
Abstract
Aims The early repolarization syndrome (ERS) can cause ventricular fibrillation (VF) and sudden death in young, otherwise healthy individuals. There are limited data suggesting that ERS might be heritable. The aim of this study was to characterize the clinical phenotype and to identify a causal variant in an affected family using an exome-sequencing approach. Methods and results Early repolarization syndrome was diagnosed according to the recently proposed Shanghai ERS Score. After sequencing of known ERS candidate genes, whole-exome sequencing (WES) was performed. The index patient (23 years, female) showed a dynamic inferolateral early repolarization (ER) pattern and electrical storm with intractable VF. Isoproterenol enabled successful termination of electrical storm with no recurrence on hydroquinidine therapy during 33 months of follow-up. The index patient’s brother (25 years) had a persistent inferior ER pattern with malignant features and a history of syncope. Both parents were asymptomatic and showed no ER pattern. While there was no pathogenic variant in candidate genes, WES detected a novel missense variant affecting a highly conserved residue (p. H2245R) in the ANK3 gene encoding Ankyrin-G in the two siblings and the father. Conclusion We identified two siblings with a malignant ERS phenotype sharing a novel ANK3 variant. A potentially pathogenic role of the novel ANK3 variant is suggested by the direct interaction of Ankyrin-G with the cardiac sodium channel, however, more patients with ANK3 variants and ERS would be required to establish ANK3 as novel ERS susceptibility gene. Our study provides additional evidence that ERS might be a heritable condition.
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Affiliation(s)
- Johannes Steinfurt
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Connie R Bezzina
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Heart Center, Amsterdam, The Netherlands
| | - Jürgen Biermann
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Dawid Staudacher
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | | | - Luca Trolese
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Thomas S Faber
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Daniel Duerschmied
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Manfred Zehender
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Christoph Bode
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Heart Center, Amsterdam, The Netherlands
| | - Katja E Odening
- Department of Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - Elisabeth M Lodder
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Heart Center, Amsterdam, The Netherlands
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Marketou ME, Zareas I, Kanoupakis E, Patrianakos A, Parthenakis F. A case series of Brugada syndrome with a novel mutation in the ankyrin-B gene: an unusual unmasking in acute myocarditis. Eur Heart J Case Rep 2021; 5:ytab225. [PMID: 34222783 PMCID: PMC8243220 DOI: 10.1093/ehjcr/ytab225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/13/2021] [Accepted: 05/12/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Brugada syndrome (BrS) is a genetically heterogeneous channelopathy that may lead to sudden death. We report a novel mutation of the ankyrin-B gene that is probably related to the occurrence of BrS in two brothers. CASE SUMMARY First, we present the case of a 27-year-old male who was admitted to the hospital with acute myocarditis. The patient showed left ventricular dysfunction and was given carvedilol. Six days later, while asymptomatic and afebrile, the patient exhibited an electrocardiogram (ECG) with repolarization 'saddleback' ST changes in V2. A procainamide provocative test was performed with a response for Type 1 Brugada ECG pattern. Genetic testing revealed a novel mutation, c.5418T>A (+/-) (p.His1806Gln), in the ankyrin-B gene encoding. His 34 years old brother had an ECG J point elevation in leads V1 and V2 of 1 mm not fulfilling diagnostic criteria for Brugada ECG pattern. He also experienced arrhythmia-related syncope. Flecainide provocation test changed ECG towards a Type 1 Brugada pattern. A subcutaneous implantable defibrillator (ICD) was implanted. Patient 1 remains asymptomatic while Patient 2 experienced an appropriate ICD shock during follow-up. DISCUSSION In this case series, two brothers with BrS exhibited the same mutation of the ankyrin-B gene. Ankyrin-B is associated with the stability of plasma membrane proteins in the voltage-gated ion channels. Our finding provides a foundation for further investigation of this mutation in relation to BrS. Moreover, the timing of its presentation raises concerns as to whether myocarditis or beta-blockers are associated with the presentation of BrS ECG.
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Affiliation(s)
- Maria E Marketou
- Cardiology Department, Heraklion University Hospital, PO Box 1352, Stavrakia, Heraklion, Crete 71110, Greece
| | - Ilias Zareas
- Cardiology Department, Agios Nikolaos General Hospital, Crete Greece
| | - Emmanuel Kanoupakis
- Cardiology Department, Heraklion University Hospital, PO Box 1352, Stavrakia, Heraklion, Crete 71110, Greece
| | - Alexandros Patrianakos
- Cardiology Department, Heraklion University Hospital, PO Box 1352, Stavrakia, Heraklion, Crete 71110, Greece
| | - Fragiskos Parthenakis
- Cardiology Department, Heraklion University Hospital, PO Box 1352, Stavrakia, Heraklion, Crete 71110, Greece
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Morotti S, Ni H, Peters CH, Rickert C, Asgari-Targhi A, Sato D, Glukhov AV, Proenza C, Grandi E. Intracellular Na + Modulates Pacemaking Activity in Murine Sinoatrial Node Myocytes: An In Silico Analysis. Int J Mol Sci 2021; 22:5645. [PMID: 34073281 PMCID: PMC8198068 DOI: 10.3390/ijms22115645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/19/2022] Open
Abstract
Background: The mechanisms underlying dysfunction in the sinoatrial node (SAN), the heart's primary pacemaker, are incompletely understood. Electrical and Ca2+-handling remodeling have been implicated in SAN dysfunction associated with heart failure, aging, and diabetes. Cardiomyocyte [Na+]i is also elevated in these diseases, where it contributes to arrhythmogenesis. Here, we sought to investigate the largely unexplored role of Na+ homeostasis in SAN pacemaking and test whether [Na+]i dysregulation may contribute to SAN dysfunction. Methods: We developed a dataset-specific computational model of the murine SAN myocyte and simulated alterations in the major processes of Na+ entry (Na+/Ca2+ exchanger, NCX) and removal (Na+/K+ ATPase, NKA). Results: We found that changes in intracellular Na+ homeostatic processes dynamically regulate SAN electrophysiology. Mild reductions in NKA and NCX function increase myocyte firing rate, whereas a stronger reduction causes bursting activity and loss of automaticity. These pathologic phenotypes mimic those observed experimentally in NCX- and ankyrin-B-deficient mice due to altered feedback between the Ca2+ and membrane potential clocks underlying SAN firing. Conclusions: Our study generates new testable predictions and insight linking Na+ homeostasis to Ca2+ handling and membrane potential dynamics in SAN myocytes that may advance our understanding of SAN (dys)function.
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Affiliation(s)
- Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Colin H. Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.H.P.); (C.R.); (C.P.)
| | - Christian Rickert
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.H.P.); (C.R.); (C.P.)
| | - Ameneh Asgari-Targhi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Alexey V. Glukhov
- Department of Medicine, Cardiovascular Medicine, University of Wisconsin Madison School of Medicine and Public Health, Madison, WI 53705, USA;
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.H.P.); (C.R.); (C.P.)
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
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Li J, Richmond B, Hong T. Cardiac T-Tubule cBIN1-Microdomain, a Diagnostic Marker and Therapeutic Target of Heart Failure. Int J Mol Sci 2021; 22:ijms22052299. [PMID: 33669042 PMCID: PMC7956774 DOI: 10.3390/ijms22052299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/19/2021] [Accepted: 02/22/2021] [Indexed: 12/23/2022] Open
Abstract
Since its first identification as a cardiac transverse tubule (t-tubule) protein, followed by the cloning of the cardiac isoform responsible for t-tubule membrane microdomain formation, cardiac bridging integrator 1 (cBIN1) and its organized microdomains have emerged as a key mechanism in maintaining normal beat-to-beat heart contraction and relaxation. The abnormal remodeling of cBIN1-microdomains occurs in stressed and diseased cardiomyocytes, contributing to the pathophysiology of heart failure. Due to the homeostatic turnover of t-tubule cBIN1-microdomains via microvesicle release into the peripheral circulation, plasma cBIN1 can be assayed as a liquid biopsy of cardiomyocyte health. A new blood test cBIN1 score (CS) has been developed as a dimensionless inverse index derived from plasma cBIN1 concentration with a diagnostic and prognostic power for clinical outcomes in stable ambulatory patients with heart failure with reduced or preserved ejection fraction (HFrEF or HFpEF). Recent evidence further indicates that exogenous cBIN1 introduced by adeno-associated virus 9-based gene therapy can rescue cardiac contraction and relaxation in failing hearts. The therapeutic potential of cBIN1 gene therapy is enormous given its ability to rescue cardiac inotropy and provide lusitropic protection in the meantime. These unprecedented capabilities of cBIN1 gene therapy are shifting the current paradigm of therapy development for heart failure, particularly HFpEF.
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Affiliation(s)
- Jing Li
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT 84112, USA; (J.L.); (B.R.)
| | - Bradley Richmond
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT 84112, USA; (J.L.); (B.R.)
| | - TingTing Hong
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT 84112, USA; (J.L.); (B.R.)
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
- Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, UT 84112, USA
- Correspondence: ; Tel.: +1-801-581-3090
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Abstract
Atrial fibrillation (AF), the common sustained arrhythmia in clinical practice, has major public health implications due to its associated morbidity and increased mortality. The AF epidemic is due to the burgeoning elderly population and the identification of novel risk factors, for example, genetics. Since the diagnosis of AF has a major impact on the clinical assessment and management of patients with inherited arrhythmia syndromes, improved understanding of the cause and pathogenesis of AF has provided important insights into the underlying pathophysiological mechanisms of this common arrhythmia and identified potential mechanism-based therapies.
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Affiliation(s)
- Baha'a Al-Azaam
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, 820 S Wood Street, Suite 920S, Chicago, IL 60612, USA; Division of Cardiology, Department of Pharmacology, University of Illinois at Chicago, 820 S Wood Street, Suite 920S, Chicago, IL 60612, USA
| | - Dawood Darbar
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, 820 S Wood Street, Suite 920S, Chicago, IL 60612, USA; Division of Cardiology, Department of Pharmacology, University of Illinois at Chicago, 820 S Wood Street, Suite 920S, Chicago, IL 60612, USA; Department of Medicine, Jesse Brown Veterans Administration, 820 S Wood Street, Suite 920S, Chicago, IL 60612, USA.
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29
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Abstract
Long QT syndrome (LQTS) is a cardiovascular disorder characterized by an abnormality in cardiac repolarization leading to a prolonged QT interval and T-wave irregularities on the surface electrocardiogram. It is commonly associated with syncope, seizures, susceptibility to torsades de pointes, and risk for sudden death. LQTS is a rare genetic disorder and a major preventable cause of sudden cardiac death in the young. The availability of therapy for this lethal disease emphasizes the importance of early and accurate diagnosis. Additionally, understanding of the molecular mechanisms underlying LQTS could help to optimize genotype-specific treatments to prevent deaths in LQTS patients. In this review, we briefly summarize current knowledge regarding molecular underpinning of LQTS, in particular focusing on LQT1, LQT2, and LQT3, and discuss novel strategies to study ion channel dysfunction and drug-specific therapies in LQT1, LQT2, and LQT3 syndromes.
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Affiliation(s)
| | - Isabelle Deschênes
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
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30
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Reilly L, Alvarado FJ, Lang D, Abozeid S, Van Ert H, Spellman C, Warden J, Makielski JC, Glukhov AV, Eckhardt LL. Genetic Loss of IK1 Causes Adrenergic-Induced Phase 3 Early Afterdepolariz ations and Polymorphic and Bidirectional Ventricular Tachycardia. Circ Arrhythm Electrophysiol 2020; 13:e008638. [PMID: 32931337 PMCID: PMC7574954 DOI: 10.1161/circep.120.008638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/23/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND Arrhythmia syndromes associated with KCNJ2 mutations have been described clinically; however, little is known of the underlying arrhythmia mechanism. We create the first patient inspired KCNJ2 transgenic mouse and study effects of this mutation on cardiac function, IK1, and Ca2+ handling, to determine the underlying cellular arrhythmic pathogenesis. METHODS A cardiac-specific KCNJ2-R67Q mouse was generated and bred for heterozygosity (R67Q+/-). Echocardiography was performed at rest, under anesthesia. In vivo ECG recording and whole heart optical mapping of intact hearts was performed before and after adrenergic stimulation in wild-type (WT) littermate controls and R67Q+/- mice. IK1 measurements, action potential characterization, and intracellular Ca2+ imaging from isolated ventricular myocytes at baseline and after adrenergic stimulation were performed in WT and R67Q+/- mice. RESULTS R67Q+/- mice (n=17) showed normal cardiac function, structure, and baseline electrical activity compared with WT (n=10). Following epinephrine and caffeine, only the R67Q+/- mice had bidirectional ventricular tachycardia, ventricular tachycardia, frequent ventricular ectopy, and/or bigeminy and optical mapping demonstrated high prevalence of spontaneous and sustained ventricular arrhythmia. Both R67Q+/- (n=8) and WT myocytes (n=9) demonstrated typical n-shaped IK1IV relationship; however, following isoproterenol, max outward IK1 increased by ≈20% in WT but decreased by ≈24% in R67Q+/- (P<0.01). R67Q+/- myocytes (n=5) demonstrated prolonged action potential duration at 90% repolarization and after 10 nmol/L isoproterenol compared with WT (n=7; P<0.05). Ca2+ transient amplitude, 50% decay rate, and sarcoplasmic reticulum Ca2+ content were not different between WT (n=18) and R67Q+/- (n=16) myocytes. R67Q+/- myocytes (n=10) under adrenergic stimulation showed frequent spontaneous development of early afterdepolarizations that occurred at phase 3 of action potential repolarization. CONCLUSIONS KCNJ2 mutation R67Q+/- causes adrenergic-dependent loss of IK1 during terminal repolarization and vulnerability to phase 3 early afterdepolarizations. This model clarifies a heretofore unknown arrhythmia mechanism and extends our understanding of treatment implications for patients with KCNJ2 mutation.
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Affiliation(s)
- Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Francisco J Alvarado
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Di Lang
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Sara Abozeid
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Hannah Van Ert
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Cordell Spellman
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jarrett Warden
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jonathan C Makielski
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Alexey V Glukhov
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
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31
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Skogestad J, Aronsen JM, Tovsrud N, Wanichawan P, Hougen K, Stokke MK, Carlson CR, Sjaastad I, Sejersted OM, Swift F. Coupling of the Na+/K+-ATPase to Ankyrin B controls Na+/Ca2+ exchanger activity in cardiomyocytes. Cardiovasc Res 2020; 116:78-90. [PMID: 30949686 DOI: 10.1093/cvr/cvz087] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/22/2019] [Accepted: 04/03/2019] [Indexed: 01/28/2023] Open
Abstract
AIMS Ankyrin B (AnkB) is an adaptor protein that assembles Na+/K+-ATPase (NKA) and Na+/Ca2+ exchanger (NCX) in the AnkB macromolecular complex. Loss-of-function mutations in AnkB cause the AnkB syndrome in humans, characterized by ventricular arrhythmias and sudden cardiac death. It is unclear to what extent NKA binding to AnkB allows regulation of local Na+ and Ca2+ domains and hence NCX activity. METHODS AND RESULTS To investigate the role of NKA binding to AnkB in cardiomyocytes, we synthesized a disruptor peptide (MAB peptide) and its AnkB binding ability was verified by pulldown experiments. As opposed to control, the correlation between NKA and NCX currents was abolished in adult rat ventricular myocytes dialyzed with MAB peptide, as well as in cardiomyocytes from AnkB+/- mice. Disruption of NKA from AnkB (with MAB peptide) increased NCX-sensed cytosolic Na+ concentration, reduced Ca2+ extrusion through NCX, and increased frequency of Ca2+ sparks and Ca2+ waves without concomitant increase in Ca2+ transient amplitude or SR Ca2+ load, suggesting an effect in local Ca2+ domains. Selective inhibition of the NKAα2 isoform abolished both the correlation between NKA and NCX currents and the increased rate of Ca2+ sparks and waves following NKA/AnkB disruption, suggesting that an AnkB/NKAα2/NCX domain controls Ca2+ fluxes in cardiomyocytes. CONCLUSION NKA binding to AnkB allows ion regulation in a local domain, and acute disruption of the NKA/AnkB interaction using disruptor peptides lead to increased rate of Ca2+ sparks and waves. The functional effects were mediated through the NKAα2 isoform. Disruption of the AnkB/NKA/NCX domain could be an important pathophysiological mechanism in the AnkB syndrome.
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Affiliation(s)
- Jonas Skogestad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Nils Tovsrud
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Pimthanya Wanichawan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Karina Hougen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Mathis Korseberg Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Cathrine Rein Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ole Mathias Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Fredrik Swift
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway.,Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
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32
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Abstract
The main inherited cardiac arrhythmias are long QT syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia and Brugada syndrome. These rare diseases are often the underlying cause of sudden cardiac death in young individuals and result from mutations in several genes encoding ion channels or proteins involved in their regulation. The genetic defects lead to alterations in the ionic currents that determine the morphology and duration of the cardiac action potential, and individuals with these disorders often present with syncope or a life-threatening arrhythmic episode. The diagnosis is based on clinical presentation and history, the characteristics of the electrocardiographic recording at rest and during exercise and genetic analyses. Management relies on pharmacological therapy, mostly β-adrenergic receptor blockers (specifically, propranolol and nadolol) and sodium and transient outward current blockers (such as quinidine), or surgical interventions, including left cardiac sympathetic denervation and implantation of a cardioverter-defibrillator. All these arrhythmias are potentially life-threatening and have substantial negative effects on the quality of life of patients. Future research should focus on the identification of genes associated with the diseases and other risk factors, improved risk stratification and, in particular for Brugada syndrome, effective therapies.
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Coban-Akdemir ZH, Charng WL, Azamian M, Paine IS, Punetha J, Grochowski CM, Gambin T, Valdes S, Cannon B, Zapata G, Hernandez PP, Jhangiani S, Doddapaneni H, Hu J, Boricha F, Muzny DM, Boerwinkle E, Yang Y, Gibbs RA, Posey JE, Wehrens XH, Belmont JW, Kim JJ, Miyake CY, Lupski JR, Lalani SR. Wolff-Parkinson-White syndrome: De novo variants and evidence for mutational burden in genes associated with atrial fibrillation. Am J Med Genet A 2020; 182:1387-1399. [PMID: 32233023 PMCID: PMC7275694 DOI: 10.1002/ajmg.a.61571] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 01/17/2020] [Accepted: 03/09/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Wolff-Parkinson-White (WPW) syndrome is a relatively common arrhythmia affecting ~1-3/1,000 individuals. Mutations in PRKAG2 have been described in rare patients in association with cardiomyopathy. However, the genetic basis of WPW in individuals with a structurally normal heart remains poorly understood. Sudden death due to atrial fibrillation (AF) can also occur in these individuals. Several studies have indicated that despite ablation of an accessory pathway, the risk of AF remains high in patients compared to general population. METHODS We applied exome sequencing in 305 subjects, including 65 trios, 80 singletons, and 6 multiple affected families. We used de novo analysis, candidate gene approach, and burden testing to explore the genetic contributions to WPW. RESULTS A heterozygous deleterious variant in PRKAG2 was identified in one subject, accounting for 0.6% (1/151) of the genetic basis of WPW in this study. Another individual with WPW and left ventricular hypertrophy carried a known pathogenic variant in MYH7. We found rare de novo variants in genes associated with arrhythmia and cardiomyopathy (ANK2, NEBL, PITX2, and PRDM16) in this cohort. There was an increased burden of rare deleterious variants (MAF ≤ 0.005) with CADD score ≥ 25 in genes linked to AF in cases compared to controls (P = .0023). CONCLUSIONS Our findings show an increased burden of rare deleterious variants in genes linked to AF in WPW syndrome, suggesting that genetic factors that determine the development of accessory pathways may be linked to an increased susceptibility of atrial muscle to AF in a subset of patients.
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Affiliation(s)
- Zeynep H. Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- These authors contributed equally to the work
| | - Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Current affiliation: Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
- These authors contributed equally to the work
| | - Mahshid Azamian
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Ingrid Sophie Paine
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Jaya Punetha
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | | | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Current affiliation: Institute of Computer Science, Warsaw University of Technology, Warsaw, Poland
| | - Santiago Valdes
- Department of Pediatrics, Division of Cardiology, Texas Children’s Hospital, Houston, Texas
| | - Bryan Cannon
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Gladys Zapata
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Patricia P. Hernandez
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Shalini Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Harsha Doddapaneni
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Jianhong Hu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Fatima Boricha
- Department of Pediatrics, the University of Texas Health Science Center at Houston, Houston, Texas
| | - Donna M. Muzny
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Eric Boerwinkle
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
- Human Genetics Center, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics Laboratories, Baylor College of Medicine, Houston, Texas
| | - Richard A. Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Xander H.T. Wehrens
- Department of Pediatrics, Division of Cardiology, Texas Children’s Hospital, Houston, Texas
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas
| | - John W. Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Department of Pediatrics, Division of Cardiology, Texas Children’s Hospital, Houston, Texas
| | - Jeffrey J. Kim
- Department of Pediatrics, Division of Cardiology, Texas Children’s Hospital, Houston, Texas
| | - Christina Y. Miyake
- Department of Pediatrics, Division of Cardiology, Texas Children’s Hospital, Houston, Texas
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
- Department of Pediatrics, Texas Children’s Hospital, Houston, Texas
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
| | - Seema R. Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
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34
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Kistamás K, Veress R, Horváth B, Bányász T, Nánási PP, Eisner DA. Calcium Handling Defects and Cardiac Arrhythmia Syndromes. Front Pharmacol 2020; 11:72. [PMID: 32161540 PMCID: PMC7052815 DOI: 10.3389/fphar.2020.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Calcium ions (Ca2+) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca2+ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca2+ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca2+ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Roland Veress
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - David A Eisner
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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35
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Essandoh K, Philippe JM, Jenkins PM, Brody MJ. Palmitoylation: A Fatty Regulator of Myocardial Electrophysiology. Front Physiol 2020; 11:108. [PMID: 32140110 PMCID: PMC7042378 DOI: 10.3389/fphys.2020.00108] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/30/2020] [Indexed: 01/02/2023] Open
Abstract
Regulation of cardiac physiology is well known to occur through the action of kinases that reversibly phosphorylate ion channels, calcium handling machinery, and signaling effectors. However, it is becoming increasingly apparent that palmitoylation or S-acylation, the post-translational modification of cysteines with saturated fatty acids, plays instrumental roles in regulating the localization, activity, stability, sorting, and function of numerous proteins, including proteins known to have essential functions in cardiomyocytes. However, the impact of this modification on cardiac physiology requires further investigation. S-acylation is catalyzed by the zDHHC family of S-acyl transferases that localize to intracellular organelle membranes or the sarcolemma. Recent work has begun to uncover functions of S-acylation in the heart, particularly in the regulation of cardiac electrophysiology, including modification of the sodium-calcium exchanger, phospholemman and the cardiac sodium pump, as well as the voltage-gated sodium channel. Elucidating the regulatory functions of zDHHC enzymes in cardiomyocytes and determination of how S-acylation is altered in the diseased heart will shed light on how these modifications participate in cardiac pathogenesis and potentially identify novel targets for the treatment of cardiovascular disease. Indeed, proteins with critical signaling roles in the heart are also S-acylated, including receptors and G-proteins, yet the dynamics and functions of these modifications in myocardial physiology have not been interrogated. Here, we will review what is known about zDHHC enzymes and substrate S-acylation in myocardial physiology and highlight future areas of investigation that will uncover novel functions of S-acylation in cardiac homeostasis and pathophysiology.
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Affiliation(s)
- Kobina Essandoh
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
| | - Julie M Philippe
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States.,Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Matthew J Brody
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
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36
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Chen L, Choi CSW, Sanchez-Arias JC, Arbour LT, Swayne LA. Ankyrin-B p.S646F undergoes increased proteasome degradation and reduces cell viability in the H9c2 rat ventricular cardiomyoblast cell line. Biochem Cell Biol 2020; 98:299-306. [PMID: 31965814 DOI: 10.1139/bcb-2019-0082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ankyrin-B (AnkB) is scaffolding protein that anchors integral membrane proteins to the cardiomyocyte cytoskeleton. We recently identified an AnkB variant, AnkB p.S646F (ANK2 c.1937 C>T) associated with a phenotype ranging from predisposition for cardiac arrhythmia to cardiomyopathy. AnkB p.S646F exhibited reduced expression levels in the H9c2 rat ventricular-derived cardiomyoblast cell line relative to wildtype AnkB. Here, we demonstrate that AnkB is regulated by proteasomal degradation and proteasome inhibition rescues AnkB p.S646F expression levels in H9c2 cells, although this effect is not conserved with differentiation. We also compared the impact of wildtype AnkB and AnkB p.S646F on cell viability and proliferation. AnkB p.S646F expression resulted in decreased cell viability at 30 h after transfection, whereas we observed a greater proportion of cycling, Ki67-positive cells at 48 h after transfection. Notably, the number of GFP-positive cells was low and was consistent between wildtype AnkB and AnkB p.S646F expressing cells, suggesting that AnkB and AnkB p.S646F affected paracrine communication between H9c2 cells differentially. This work reveals that AnkB levels are regulated by the proteasome and that AnkB p.S646F compromises cell viability. Together, these findings provide key new insights into the putative cellular and molecular mechanisms of AnkB-related cardiac disease.
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Affiliation(s)
- Lena Chen
- Divison of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Catherine S W Choi
- Divison of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | | | - Laura T Arbour
- Divison of Medical Sciences, University of Victoria, Victoria, BC, Canada.,Island Medical Program, University of British Columbia, Victoria, BC, Canada.,Department of Medical Genetics, University of British Columbia, Victoria, BC, Canada
| | - Leigh Anne Swayne
- Divison of Medical Sciences, University of Victoria, Victoria, BC, Canada.,Island Medical Program, University of British Columbia, Victoria, BC, Canada
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37
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Neira V, Enriquez A, Simpson C, Baranchuk A. Update on long QT syndrome. J Cardiovasc Electrophysiol 2019; 30:3068-3078. [PMID: 31596038 DOI: 10.1111/jce.14227] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/17/2019] [Accepted: 10/05/2019] [Indexed: 12/24/2022]
Abstract
Long QT syndrome (LQTS) is an inherited disorder characterized by a prolonged QT interval in the 12-lead electrocardiogram and increased risk of malignant arrhythmias in patients with a structurally normal heart. Since its first description in the 1950s, advances in molecular genetics have greatly improved our understanding of the cause and mechanisms of this disease. Sixteen genes linked to LQTS have been described and genetic testing had become an integral part of the diagnosis and risk stratification. This article provides an updated review of the genetic basis, diagnosis, and clinical management of LQTS.
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Affiliation(s)
- Víctor Neira
- Division of Cardiology, Queen's University, Kingston, Ontario, Canada
| | - Andrés Enriquez
- Division of Cardiology, Queen's University, Kingston, Ontario, Canada
| | - Chris Simpson
- Division of Cardiology, Queen's University, Kingston, Ontario, Canada
| | - Adrian Baranchuk
- Division of Cardiology, Queen's University, Kingston, Ontario, Canada
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38
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Krasi G, Precone V, Paolacci S, Stuppia L, Nodari S, Romeo F, Perrone M, Bushati V, Dautaj A, Bertelli M. Genetics and pharmacogenetics in the diagnosis and therapy of cardiovascular diseases. ACTA BIO-MEDICA : ATENEI PARMENSIS 2019; 90:7-19. [PMID: 31577248 PMCID: PMC7233637 DOI: 10.23750/abm.v90i10-s.8748] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 08/05/2019] [Indexed: 12/20/2022]
Abstract
Cardiovascular diseases are the main cause of death worldwide. The ability to accurately define individual susceptibility to these disorders is therefore of strategic importance. Linkage analysis and genome-wide association studies have been useful for the identification of genes related to cardiovascular diseases. The identification of variants predisposing to cardiovascular diseases contributes to the risk profile and the possibility of tailored preventive or therapeutic strategies. Molecular genetics and pharmacogenetics are playing an increasingly important role in the correct clinical management of patients. For instance, genetic testing can identify variants that influence how patients metabolize medications, making it possible to prescribe personalized, safer and more efficient treatments, reducing medical costs and improving clinical outcomes. In the near future we can expect a great increment in information and genetic testing, which should be acknowledged as a true branch of diagnostics in cardiology, like hemodynamics and electrophysiology. In this review we summarize the genetics and pharmacogenetics of the main cardiovascular diseases, showing the role played by genetic information in the identification of cardiovascular risk factors and in the diagnosis and therapy of these conditions. (www.actabiomedica.it)
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39
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Zhu W, Wang C, Hu J, Wan R, Yu J, Xie J, Ma J, Guo L, Ge J, Qiu Y, Chen L, Liu H, Yan X, Liu X, Ye J, He W, Shen Y, Wang C, Mohler PJ, Hong K. Ankyrin-B Q1283H Variant Linked to Arrhythmias Via Loss of Local Protein Phosphatase 2A Activity Causes Ryanodine Receptor Hyperphosphorylation. Circulation 2019; 138:2682-2697. [PMID: 30571258 PMCID: PMC6276866 DOI: 10.1161/circulationaha.118.034541] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Human loss-of-function variants of ANK2 (ankyrin-B) are linked to arrhythmias and sudden cardiac death. However, their in vivo effects and specific arrhythmogenic pathways have not been fully elucidated. Methods: We identified new ANK2 variants in 25 unrelated Han Chinese probands with ventricular tachycardia by whole-exome sequencing. The potential pathogenic variants were validated by Sanger sequencing. We performed functional and mechanistic experiments in ankyrin-B knockin (KI) mouse models and in single myocytes isolated from KI hearts. Results: We detected a rare, heterozygous ANK2 variant (p.Q1283H) in a proband with recurrent ventricular tachycardia. This variant was localized to the ZU5C region of ANK2, where no variants have been previously reported. KI mice harboring the p.Q1283H variant exhibited an increased predisposition to ventricular arrhythmias after catecholaminergic stress in the absence of cardiac structural abnormalities. Functional studies illustrated an increased frequency of delayed afterdepolarizations and Ca2+ waves and sparks accompanied by decreased sarcoplasmic reticulum Ca2+ content in KI cardiomyocytes on isoproterenol stimulation. The immunoblotting results showed increased levels of phosphorylated ryanodine receptor Ser2814 in the KI hearts, which was further amplified on isoproterenol stimulation. Coimmunoprecipitation experiments demonstrated dissociation of protein phosphatase 2A from ryanodine receptor in the KI hearts, which was accompanied by a decreased binding of ankyrin-B to protein phosphatase 2A regulatory subunit B56α. Finally, the administration of metoprolol or flecainide decreased the incidence of stress-induced ventricular arrhythmias in the KI mice. Conclusions: ANK2 p.Q1283H is a disease-associated variant that confers susceptibility to stress-induced arrhythmias, which may be prevented by the administration of metoprolol or flecainide. This variant is associated with the loss of protein phosphatase 2A activity, increased phosphorylation of ryanodine receptor, exaggerated delayed afterdepolarization-mediated trigger activity, and arrhythmogenesis.
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Affiliation(s)
- Wengen Zhu
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Cen Wang
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Jinzhu Hu
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Rong Wan
- Jiangxi Key Laboratory of Molecular Medicine (R.W., J.X., X.Y., X.L., W.H., Y.S., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Jianhua Yu
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Jinyan Xie
- Jiangxi Key Laboratory of Molecular Medicine (R.W., J.X., X.Y., X.L., W.H., Y.S., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Jianyong Ma
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Linjuan Guo
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Jin Ge
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Yumin Qiu
- Department of General Surgery (Y.Q., L.C.), Second Affiliated Hospital of Nanchang University, China
| | - Leifeng Chen
- Department of General Surgery (Y.Q., L.C.), Second Affiliated Hospital of Nanchang University, China
| | - Hualong Liu
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Xia Yan
- Jiangxi Key Laboratory of Molecular Medicine (R.W., J.X., X.Y., X.L., W.H., Y.S., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Xiuxia Liu
- Jiangxi Key Laboratory of Molecular Medicine (R.W., J.X., X.Y., X.L., W.H., Y.S., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Jin Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui (J.Y., C.W.)
| | - Wenfeng He
- Jiangxi Key Laboratory of Molecular Medicine (R.W., J.X., X.Y., X.L., W.H., Y.S., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Yang Shen
- Jiangxi Key Laboratory of Molecular Medicine (R.W., J.X., X.Y., X.L., W.H., Y.S., K.H.), Second Affiliated Hospital of Nanchang University, China
| | - Chao Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui (J.Y., C.W.)
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, College of Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Departments of Physiology and Cell Biology and Internal Medicine, Columbus (P.J.M.)
| | - Kui Hong
- Department of Cardiovascular Medicine (W.Z., C.W., J.H., J.Y., J.M., L.G., J.G., H.L., K.H.), Second Affiliated Hospital of Nanchang University, China.,Jiangxi Key Laboratory of Molecular Medicine (R.W., J.X., X.Y., X.L., W.H., Y.S., K.H.), Second Affiliated Hospital of Nanchang University, China
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40
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Choi CSW, Souza IA, Sanchez-Arias JC, Zamponi GW, Arbour LT, Swayne LA. Ankyrin B and Ankyrin B variants differentially modulate intracellular and surface Cav2.1 levels. Mol Brain 2019; 12:75. [PMID: 31477143 PMCID: PMC6720858 DOI: 10.1186/s13041-019-0494-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/21/2019] [Indexed: 12/11/2022] Open
Abstract
Ankyrin B (AnkB) is an adaptor and scaffold for motor proteins and various ion channels that is ubiquitously expressed, including in the brain. AnkB has been associated with neurological disorders such as epilepsy and autism spectrum disorder, but understanding of the underlying mechanisms is limited. Cav2.1, the pore-forming subunit of P/Q type voltage gated calcium channels, is a known interactor of AnkB and plays a crucial role in neuronal function. Here we report that wildtype AnkB increased overall Cav2.1 levels without impacting surface Cav2.1 levels in HEK293T cells. An AnkB variant, p.S646F, which we recently discovered to be associated with seizures, further increased overall Cav2.1 levels, again with no impact on surface Cav2.1 levels. AnkB p.Q879R, on the other hand, increased surface Cav2.1 levels in the presence of accessory subunits α2δ1 and β4. Additionally, AnkB p.E1458G decreased surface Cav2.1 irrespective of the presence of accessory subunits. In addition, we found that partial deletion of AnkB in cortex resulted in a decrease in overall Cav2.1 levels, with no change to the levels of Cav2.1 detected in synaptosome fractions. Our work suggests that depending on the particular variant, AnkB regulates intracellular and surface Cav2.1. Notably, expression of the AnkB variant associated with seizure (AnkB p.S646F) caused further increase in intracellular Cav2.1 levels above that of even wildtype AnkB. These novel findings have important implications for understanding the role of AnkB and Cav2.1 in the regulation of neuronal function in health and disease.
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Affiliation(s)
- Catherine S. W. Choi
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia Canada
| | - Ivana A. Souza
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta Canada
| | - Juan C. Sanchez-Arias
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia Canada
| | - Gerald W. Zamponi
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta Canada
| | - Laura T. Arbour
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia Canada
| | - Leigh Anne Swayne
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia Canada
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41
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Roberts JD, Murphy NP, Hamilton RM, Lubbers ER, James CA, Kline CF, Gollob MH, Krahn AD, Sturm AC, Musa H, El-Refaey M, Koenig S, Aneq MÅ, Hoorntje ET, Graw SL, Davies RW, Rafiq MA, Koopmann TT, Aafaqi S, Fatah M, Chiasson DA, Taylor MR, Simmons SL, Han M, van Opbergen CJ, Wold LE, Sinagra G, Mittal K, Tichnell C, Murray B, Codima A, Nazer B, Nguyen DT, Marcus FI, Sobriera N, Lodder EM, van den Berg MP, Spears DA, Robinson JF, Ursell PC, Green AK, Skanes AC, Tang AS, Gardner MJ, Hegele RA, van Veen TA, Wilde AA, Healey JS, Janssen PM, Mestroni L, van Tintelen JP, Calkins H, Judge DP, Hund TJ, Scheinman MM, Mohler PJ. Ankyrin-B dysfunction predisposes to arrhythmogenic cardiomyopathy and is amenable to therapy. J Clin Invest 2019; 129:3171-3184. [PMID: 31264976 PMCID: PMC6668697 DOI: 10.1172/jci125538] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 05/14/2019] [Indexed: 01/11/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is an inherited arrhythmia syndrome characterized by severe structural and electrical cardiac phenotypes, including myocardial fibrofatty replacement and sudden cardiac death. Clinical management of ACM is largely palliative, owing to an absence of therapies that target its underlying pathophysiology, which stems partially from our limited insight into the condition. Following identification of deceased ACM probands possessing ANK2 rare variants and evidence of ankyrin-B loss of function on cardiac tissue analysis, an ANK2 mouse model was found to develop dramatic structural abnormalities reflective of human ACM, including biventricular dilation, reduced ejection fraction, cardiac fibrosis, and premature death. Desmosomal structure and function appeared preserved in diseased human and murine specimens in the presence of markedly abnormal β-catenin expression and patterning, leading to identification of a previously unknown interaction between ankyrin-B and β-catenin. A pharmacological activator of the WNT/β-catenin pathway, SB-216763, successfully prevented and partially reversed the murine ACM phenotypes. Our findings introduce what we believe to be a new pathway for ACM, a role of ankyrin-B in cardiac structure and signaling, a molecular link between ankyrin-B and β-catenin, and evidence for targeted activation of the WNT/β-catenin pathway as a potential treatment for this disease.
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Affiliation(s)
- Jason D. Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, UCSF, San Francisco, California, USA
| | - Nathaniel P. Murphy
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Robert M. Hamilton
- The Labatt Family Heart Centre (Department of Pediatrics) and Translational Medicine, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
| | - Ellen R. Lubbers
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Cynthia A. James
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Crystal F. Kline
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Michael H. Gollob
- Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Andrew D. Krahn
- Heart Rhythm Services, Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amy C. Sturm
- Genomic Medicine Institute, Geisinger, Danville, Pennsylvania, USA
| | - Hassan Musa
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Mona El-Refaey
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Sara Koenig
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Meriam Åström Aneq
- Department of Clinical Physiology and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Edgar T. Hoorntje
- Netherlands Heart Institute, Utrecht, Netherlands
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Sharon L. Graw
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, Colorado, USA
| | - Robert W. Davies
- Program in Genetics and Genome Biology and The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Muhammad Arshad Rafiq
- The Labatt Family Heart Centre (Department of Pediatrics) and Translational Medicine, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
- Department of Bioscience, COMSATS University, Islamabad, Pakistan
| | - Tamara T. Koopmann
- The Labatt Family Heart Centre (Department of Pediatrics) and Translational Medicine, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
| | - Shabana Aafaqi
- The Labatt Family Heart Centre (Department of Pediatrics) and Translational Medicine, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
| | - Meena Fatah
- The Labatt Family Heart Centre (Department of Pediatrics) and Translational Medicine, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
| | - David A. Chiasson
- Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Matthew R.G. Taylor
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, Colorado, USA
| | - Samantha L. Simmons
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Mei Han
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Chantal J.M. van Opbergen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center, Utrecht, Utrecht University, Utrecht, Netherlands
| | - Loren E. Wold
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | | | - Kirti Mittal
- The Labatt Family Heart Centre (Department of Pediatrics) and Translational Medicine, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
| | - Crystal Tichnell
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Brittney Murray
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alberto Codima
- Department of Medicine, University of Sao Paulo, Sao Paulo, Brazil
| | - Babak Nazer
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Duy T. Nguyen
- Section of Cardiac Electrophysiology, Division of Cardiology, University of Colorado, Aurora, Colorado, USA
| | - Frank I. Marcus
- Division of Cardiology, Sarver Heart Center, University of Arizona, Tucson, Arizona, USA
| | - Nara Sobriera
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Elisabeth M. Lodder
- Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Maarten P. van den Berg
- Department of Cardiology, University of Groningen, University Medical Centre Groningen, Groningen, Netherlands
| | - Danna A. Spears
- Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
| | - John F. Robinson
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | | | - Anna K. Green
- Departments of Clinical Genetics and Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Allan C. Skanes
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada
| | - Anthony S. Tang
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada
| | - Martin J. Gardner
- Division of Cardiology, Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert A. Hegele
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Toon A.B. van Veen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center, Utrecht, Utrecht University, Utrecht, Netherlands
| | - Arthur A.M. Wilde
- Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Jeff S. Healey
- Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Paul M.L. Janssen
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Luisa Mestroni
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver, Aurora, Colorado, USA
| | - J. Peter van Tintelen
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Amsterdam UMC, University of Amsterdam, Department of Clinical Genetics, Amsterdam, Netherlands
- Department of Genetics, University Medical Center Utrecht (UMCU), Utrecht, Netherlands
| | - Hugh Calkins
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Daniel P. Judge
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Thomas J. Hund
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Melvin M. Scheinman
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, UCSF, San Francisco, California, USA
| | - Peter J. Mohler
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Departments of Physiology and Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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Grimes KM, Prasad V, McNamara JW. Supporting the heart: Functions of the cardiomyocyte's non-sarcomeric cytoskeleton. J Mol Cell Cardiol 2019; 131:187-196. [PMID: 30978342 DOI: 10.1016/j.yjmcc.2019.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 02/06/2023]
Abstract
The non-contractile cytoskeleton in cardiomyocytes is comprised of cytoplasmic actin, microtubules, and intermediate filaments. In addition to providing mechanical support to these cells, these structures are important effectors of tension-sensing and signal transduction and also provide networks for the transport of proteins and organelles. The majority of our knowledge on the function and structure of these cytoskeletal networks comes from research on proliferative cell types. However, in recent years, researchers have begun to show that there are important cardiomyocyte-specific functions of the cytoskeleton. Here we will discuss the current state of cytoskeletal biology in cardiomyocytes, as well as research from other cell types, that together suggest there is a wealth of knowledge on cardiac health and disease waiting to be uncovered through exploration of the complex signaling networks of cardiomyocyte non-sarcomeric cytoskeletal proteins.
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Affiliation(s)
- Kelly M Grimes
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
| | - Vikram Prasad
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - James W McNamara
- Heart, Lung and Vascular Institute, University of Cincinnati, Cincinnati, OH, USA
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Gessner G, Runge S, Koenen M, Heinemann SH, Koenen M, Haas J, Meder B, Thomas D, Katus HA, Schweizer PA. ANK2 functionally interacts with KCNH2 aggravating long QT syndrome in a double mutation carrier. Biochem Biophys Res Commun 2019; 512:845-851. [PMID: 30929919 DOI: 10.1016/j.bbrc.2019.03.162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 03/24/2019] [Indexed: 10/27/2022]
Abstract
Pathogenic long QT mutations often comprise high phenotypic variability and particularly variants in ANK2 (long QT syndrome 4) frequently lack QT prolongation. We sought to elucidate the genetic and functional background underlying the clinical diversity in a 3-generation family with different cardiac arrhythmias. Next-generation sequencing-based screening of patients with QT prolongation identified the index patient of the family carrying an ANK2-E1813K variant and a previously uncharacterized KCNH2-H562R mutation in a double heterozygous conformation. The patient presented with a severe clinical phenotype including a markedly prolonged QTc interval (544 ms), recurrent syncope due to Torsade de Pointes tachycardias, survived cardiopulmonary resuscitation, progressive cardiac conduction defect, and atrial fibrillation. Evaluation of other family members identified a sister and a niece solely carrying the ANK2-E1813K variant, who showed age-related conduction disease. An asymptomatic second sister solely carried the KCNH2-H562R mutation. Voltage-clamp recordings in Xenopus oocytes revealed that KCNH2-H562R subunits were non-functional but did not exert dominant-negative effects on wild-type subunits. Expression of KCNH2-H562R in HEK293 cells showed a trafficking deficiency. Co-expression of the C-terminal regulatory domain of ANK2 in Xenopus oocytes revealed that ANK2-E1813K diminished currents mediated by the combination of wild-type and H562R KCNH2 subunits. Our data suggest that ANK2 functionally interacts with KCNH2 leading to a stronger current suppression and marked aggravation of long QT syndrome in the patient carrying variants in both proteins.
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Affiliation(s)
- Guido Gessner
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-St. 2, D-07745, Jena, Germany
| | - Sarah Runge
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Michael Koenen
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstr. 29, D-69120, Heidelberg, Germany
| | - Stefan H Heinemann
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-St. 2, D-07745, Jena, Germany
| | - Mascha Koenen
- Institute for Comparative and Molecular Endocrinology, University of Ulm, Helmholtzstr. 8/1, D-89081, Ulm, Germany
| | - Jan Haas
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Benjamin Meder
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Patrick A Schweizer
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany.
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Aiba T. Recent understanding of clinical sequencing and gene-based risk stratification in inherited primary arrhythmia syndrome. J Cardiol 2019; 73:335-342. [PMID: 30910390 DOI: 10.1016/j.jjcc.2019.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 01/07/2019] [Indexed: 12/19/2022]
Abstract
Inherited primary arrhythmia syndromes (IPAS) may result in ventricular tachycardia or ventricular fibrillation by some genetic disorders, leading to sudden cardiac death. IPAS are also called "channelopathies" since many of these are caused by an abnormality in myocardial ion channels. Congenital long-QT syndrome (LQTS) is the most well documented IPAS, which may be seen in 0.1% of the general population. More than 15 disease-causing genes have been identified in almost 70% of LQTS patients and genetic testing is well applied to not only clinical diagnosis but also risk stratification and gene-based therapeutic strategy for each person with LQTS. Thus, in LQTS, gene-based personalized medicine can be realized. Unlike the LQTS, genetic testing for the Brugada syndrome (BrS) is still controversial since only 20% of patients can be identified with the causing gene mutations, most of which are in SCN5A. Furthermore, even in the SCN5A mutation-positive carriers, their phenotypes are not completely consistent with BrS, but may cause other IPAS including LQTS, cardiac conduction defect, sick sinus syndrome, and dilated cardiomyopathy. On the other hand, a recent Japanese BrS registry demonstrated that the pore-region mutations in SCN5A are significantly associated with a risk of lethal cardiac events. Furthermore, a genome-wide association study revealed that a common variant in SCN10A or HEY2 in addition to SCN5A is associated with BrS, thus, BrS may not be a monogenic Mendelian disease but probably an oligogenic disease. The purpose of this review is to describe the basic genetic and pathophysiological findings of the IPAS, particularly LQTS and Brugada syndrome, and to outline a rational approach to genetic testing, management, and family screening.
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Affiliation(s)
- Takeshi Aiba
- Department of Advanced Arrhythmia and Translational Medical Science, National Cerebral and Cardiovascular Center, Osaka, Japan.
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Lang D, Glukhov AV. Functional Microdomains in Heart's Pacemaker: A Step Beyond Classical Electrophysiology and Remodeling. Front Physiol 2018; 9:1686. [PMID: 30538641 PMCID: PMC6277479 DOI: 10.3389/fphys.2018.01686] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/09/2018] [Indexed: 12/12/2022] Open
Abstract
Spontaneous beating of the sinoatrial node (SAN), the primary pacemaker of the heart, is initiated, sustained, and regulated by a complex system that integrates ion channels and transporters on the cell membrane surface (often referred to as "membrane clock") with subcellular calcium handling machinery (by parity of reasoning referred to as an intracellular "Ca2+ clock"). Stable, rhythmic beating of the SAN is ensured by a rigorous synchronization between these two clocks highlighted in the coupled-clock system concept of SAN timekeeping. The emerging results demonstrate that such synchronization of the complex pacemaking machinery at the cellular level depends on tightly regulated spatiotemporal signals which are restricted to precise sub-cellular microdomains and associated with discrete clusters of different ion channels, transporters, and regulatory receptors. It has recently become evident that within the microdomains, various proteins form an interacting network and work together as a part of a macromolecular signaling complex. These protein-protein interactions are tightly controlled and regulated by a variety of neurohormonal signaling pathways and the diversity of cellular responses achieved with a limited pool of second messengers is made possible through the organization of essential signal components in particular microdomains. In this review, we highlight the emerging understanding of the functionality of distinct subcellular microdomains in SAN myocytes and their functional role in the accumulation and neurohormonal regulation of proteins involved in cardiac pacemaking. We also demonstrate how changes in scaffolding proteins may lead to microdomain-targeted remodeling and regulation of pacemaker proteins contributing to SAN dysfunction.
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Affiliation(s)
- Di Lang
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Alexey V Glukhov
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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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.
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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
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Abstract
The discovery of the human genome has ushered in a new era of molecular testing, advancing our knowledge and ability to identify cardiac channelopathies. Genetic variations can affect the opening and closing of the potassium, sodium, and calcium channels, resulting in arrhythmias and sudden death. Cardiac arrhythmias caused by disorders of ion channels are known as cardiac channelopathies. Nurses are important members of many interdisciplinary teams and must have a general understanding of the pathophysiology of the most commonly encountered cardiac channelopathies, electrocardiogram characteristics, approaches to treatment, and care for patients and their families. This article provides an overview of cardiac channelopathies that nurses might encounter in an array of clinical and research settings, focusing on the clinically relevant features of long QT syndrome, short QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, and arrhythmogenic right ventricular dysplasia/cardiomyopathy.
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Affiliation(s)
- Kathleen T Hickey
- Kathleen T. Hickey is Professor of Nursing, Columbia University Medical Center, 622 W 168th St, New York, NY 10032 . Amir Elzomor is a premedical student at the Albert Dorman Honors College at the New Jersey Institute of Technology, Newark, New Jersey
| | - Amir Elzomor
- Kathleen T. Hickey is Professor of Nursing, Columbia University Medical Center, 622 W 168th St, New York, NY 10032 . Amir Elzomor is a premedical student at the Albert Dorman Honors College at the New Jersey Institute of Technology, Newark, New Jersey
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Wilders R, Verkerk AO. Long QT Syndrome and Sinus Bradycardia-A Mini Review. Front Cardiovasc Med 2018; 5:106. [PMID: 30123799 PMCID: PMC6085426 DOI: 10.3389/fcvm.2018.00106] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 07/16/2018] [Indexed: 12/16/2022] Open
Abstract
Congenital long-QT syndrome (LQTS) is an inherited cardiac disorder characterized by the prolongation of ventricular repolarization, susceptibility to Torsades de Pointes (TdP), and a risk for sudden death. Various types of congenital LQTS exist, all due to specific defects in ion channel-related genes. Interestingly, almost all of the ion channels affected by the various types of LQTS gene mutations are also expressed in the human sinoatrial node (SAN). It is therefore not surprising that LQTS is frequently associated with a change in basal heart rate (HR). However, current data on how the LQTS-associated ion channel defects result in impaired human SAN pacemaker activity are limited. In this mini-review, we provide an overview of known LQTS mutations with effects on HR and the underlying changes in expression and kinetics of ion channels. Sinus bradycardia has been reported in relation to a large number of LQTS mutations. However, the occurrence of both QT prolongation and sinus bradycardia on a family basis is almost completely limited to LQTS types 3 and 4 (LQT3 and Ankyrin-B syndrome, respectively). Furthermore, a clear causative role of this sinus bradycardia in cardiac events seems reserved to mutations underlying LQT3.
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Affiliation(s)
- Ronald Wilders
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Arie O Verkerk
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam University Medical Centers, Amsterdam, Netherlands
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Abstract
PURPOSE OF REVIEW Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a life-threatening syndrome defined by exercise-induced or emotion-induced ventricular arrhythmias, typically caused by gain-of-function mutations in RYR2-encoded ryanodine receptor-2 (RyR2). This review will discuss recent advances and ongoing challenges in devising genotype-specific CPVT therapies. RECENT FINDINGS CPVT patients were once universally thought to be at high risk of sudden death; however, as more cases emerge, CPVT is being re-defined as a complex syndrome of variable expressivity. Treatment was traditionally limited to β-blockers and implantable cardioverter defibrillators, and although β-blockers remain a mainstay of treatment, implantable cardioverter defibrillator use is associated with adverse events and should be limited. New applications for older therapies, like flecainide and cardiac denervation, appear to better target the mechanistic basis of CPVT arrhythmias. Recent advances in our understanding of RyR2 structure and function can help in identifying novel therapeutic targets. SUMMARY CPVT is usually related to RyR2 or associated proteins. Emerging studies reveal several genotype-phenotype correlations, which may eventually influence therapeutic decision-making. Flecainide has improved CPVT outcomes and will likely have broader clinical indications in the near future. Gene therapy has shown promise in animal models but has yet to be studied in humans. Sudden death can occur as a sentinel symptom, making preventive therapy that targets molecular mechanism(s) of arrhythmia a key area of ongoing investigation. VIDEO ABSTRACT.
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