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Gallego-Delgado M, Cámara-Checa A, Rubio-Alarcón M, Heredero-Jung D, de la Fuente-Blanco L, Rapún J, Plata-Izquierdo B, Pérez-Martín S, Cebrián J, Moreno de Redrojo L, García-Berrocal B, Delpón E, Sánchez PL, Villacorta E, Caballero R. Variable Penetrance and Expressivity of a Rare Pore Loss-of-Function Mutation (p.L889V) of Nav1.5 Channels in Three Spanish Families. Int J Mol Sci 2024; 25:4686. [PMID: 38731905 PMCID: PMC11083067 DOI: 10.3390/ijms25094686] [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: 02/27/2024] [Revised: 04/05/2024] [Accepted: 04/10/2024] [Indexed: 05/13/2024] Open
Abstract
A novel rare mutation in the pore region of Nav1.5 channels (p.L889V) has been found in three unrelated Spanish families that produces quite diverse phenotypic manifestations (Brugada syndrome, conduction disease, dilated cardiomyopathy, sinus node dysfunction, etc.) with variable penetrance among families. We clinically characterized the carriers and recorded the Na+ current (INa) generated by p.L889V and native (WT) Nav1.5 channels, alone or in combination, to obtain further insight into the genotypic-phenotypic relationships in patients carrying SCN5A mutations and in the molecular determinants of the Nav1.5 channel function. The variant produced a strong dominant negative effect (DNE) since the peak INa generated by p.L889V channels expressed in Chinese hamster ovary cells, either alone (-69.4 ± 9.0 pA/pF) or in combination with WT (-62.2 ± 14.6 pA/pF), was significantly (n ≥ 17, p < 0.05) reduced compared to that generated by WT channels alone (-199.1 ± 44.1 pA/pF). The mutation shifted the voltage dependence of channel activation and inactivation to depolarized potentials, did not modify the density of the late component of INa, slightly decreased the peak window current, accelerated the recovery from fast and slow inactivation, and slowed the induction kinetics of slow inactivation, decreasing the fraction of channels entering this inactivated state. The membrane expression of p.L889V channels was low, and in silico molecular experiments demonstrated profound alterations in the disposition of the pore region of the mutated channels. Despite the mutation producing a marked DNE and reduction in the INa and being located in a critical domain of the channel, its penetrance and expressivity are quite variable among the carriers. Our results reinforce the argument that the incomplete penetrance and phenotypic variability of SCN5A loss-of-function mutations are the result of a combination of multiple factors, making it difficult to predict their expressivity in the carriers despite the combination of clinical, genetic, and functional studies.
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Affiliation(s)
- María Gallego-Delgado
- Department of Cardiology, CSUR Cardiopatías Familiares, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y León (SACYL), 37007 Salamaca, Spain; (M.G.-D.)
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
| | - Anabel Cámara-Checa
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, 28040 Madrid, Spain
| | - Marcos Rubio-Alarcón
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, 28040 Madrid, Spain
| | - David Heredero-Jung
- Department of Biochemistry, CSUR Cardiopatías Familiares, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y León (SACYL), 37007 Salamaca, Spain
| | - Laura de la Fuente-Blanco
- Department of Cardiology, CSUR Cardiopatías Familiares, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y León (SACYL), 37007 Salamaca, Spain; (M.G.-D.)
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
| | - Josu Rapún
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, 28040 Madrid, Spain
| | - Beatriz Plata-Izquierdo
- Department of Pediatrics, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y Leon (SACYL), CIBERCV, 37007 Salamaca, Spain;
| | - Sara Pérez-Martín
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, 28040 Madrid, Spain
| | - Jorge Cebrián
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, 28040 Madrid, Spain
| | - Lucía Moreno de Redrojo
- Department of Cardiology, CSUR Cardiopatías Familiares, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y León (SACYL), 37007 Salamaca, Spain; (M.G.-D.)
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
| | - Belén García-Berrocal
- Department of Biochemistry, CSUR Cardiopatías Familiares, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y León (SACYL), 37007 Salamaca, Spain
| | - Eva Delpón
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, 28040 Madrid, Spain
| | - Pedro L. Sánchez
- Department of Cardiology, CSUR Cardiopatías Familiares, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y León (SACYL), 37007 Salamaca, Spain; (M.G.-D.)
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
| | - Eduardo Villacorta
- Department of Cardiology, CSUR Cardiopatías Familiares, Institute of Biomedical Research of Salamanca (IBSAL), Complejo Asistencial Universitario de Salamanca, Gerencia Regional de Salud de Castilla y León (SACYL), 37007 Salamaca, Spain; (M.G.-D.)
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
| | - Ricardo Caballero
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain (M.R.-A.); (J.R.); (J.C.); (R.C.)
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, 28040 Madrid, Spain
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Jonker T, Barnett P, Boink GJJ, Christoffels VM. Role of Genetic Variation in Transcriptional Regulatory Elements in Heart Rhythm. Cells 2023; 13:4. [PMID: 38201209 PMCID: PMC10777909 DOI: 10.3390/cells13010004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 01/12/2024] Open
Abstract
Genetic predisposition to cardiac arrhythmias has been a field of intense investigation. Research initially focused on rare hereditary arrhythmias, but over the last two decades, the role of genetic variation (single nucleotide polymorphisms) in heart rate, rhythm, and arrhythmias has been taken into consideration as well. In particular, genome-wide association studies have identified hundreds of genomic loci associated with quantitative electrocardiographic traits, atrial fibrillation, and less common arrhythmias such as Brugada syndrome. A significant number of associated variants have been found to systematically localize in non-coding regulatory elements that control the tissue-specific and temporal transcription of genes encoding transcription factors, ion channels, and other proteins. However, the identification of causal variants and the mechanism underlying their impact on phenotype has proven difficult due to the complex tissue-specific, time-resolved, condition-dependent, and combinatorial function of regulatory elements, as well as their modest conservation across different model species. In this review, we discuss research efforts aimed at identifying and characterizing-trait-associated variant regulatory elements and the molecular mechanisms underlying their impact on heart rate or rhythm.
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Affiliation(s)
- Timo Jonker
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, 1105 AZ Amsterdam, The Netherlands; (T.J.); (P.B.); (G.J.J.B.)
| | - Phil Barnett
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, 1105 AZ Amsterdam, The Netherlands; (T.J.); (P.B.); (G.J.J.B.)
| | - Gerard J. J. Boink
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, 1105 AZ Amsterdam, The Netherlands; (T.J.); (P.B.); (G.J.J.B.)
- Department of Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, 1105 AZ Amsterdam, The Netherlands
| | - Vincent M. Christoffels
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, 1105 AZ Amsterdam, The Netherlands; (T.J.); (P.B.); (G.J.J.B.)
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Zhang Z, Brugada P, Weiss JN, Qu Z. Phase 2 Re-Entry Without I to: Role of Sodium Channel Kinetics in Brugada Syndrome Arrhythmias. JACC Clin Electrophysiol 2023; 9:2459-2474. [PMID: 37831035 DOI: 10.1016/j.jacep.2023.08.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/27/2023] [Accepted: 08/23/2023] [Indexed: 10/14/2023]
Abstract
BACKGROUND In Brugada syndrome (BrS), phase 2 re-excitation/re-entry (P2R) induced by the transient outward potassium current (Ito) is a proposed arrhythmia mechanism; yet, the most common genetic defects are loss-of-function sodium channel mutations. OBJECTIVES The authors used computer simulations to investigate how sodium channel dysfunction affects P2R-mediated arrhythmogenesis in the presence and absence of Ito. METHODS Computer simulations were carried out in 1-dimensional cables and 2-dimensional tissue using guinea pig and human ventricular action potential models. RESULTS In the presence of Ito sufficient to generate robust P2R, reducing sodium current (INa) peak amplitude alone only slightly potentiated P2R. When INa inactivation kinetics were also altered to simulate reported effects of BrS mutations and sodium channel blockers, however, P2R occurred even in the absence of Ito. These effects could be potentiated by delaying L-type calcium channel activation or increasing ATP-sensitive potassium current, consistent with experimental and clinical findings. INa-mediated P2R also accounted for sex-related, day and night-related, and fever-related differences in arrhythmia risk in BrS patients. CONCLUSIONS Altered INa kinetics synergize powerfully with reduced INa amplitude to promote P2R-induced arrhythmias in BrS in the absence of Ito, establishing a robust mechanistic link between altered INa kinetics and the P2R-mediated arrhythmia mechanism.
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Affiliation(s)
- Zhaoyang Zhang
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, Zhejiang, China; Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Pedro Brugada
- Heart Rhythm Management Centre, Postgraduate Program in Cardiac Electrophysiology and Pacing, Universitair Ziekenhuis Brussel-Vrije Universiteit Brussel, European Reference Networks Guard-Heart, Brussels, Belgium
| | - James N Weiss
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Zhilin Qu
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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Minard AY, Clark CJ, Ahern CA, Piper RC. Beta-subunit-eliminated eHAP expression (BeHAPe) cells reveal subunit regulation of the cardiac voltage-gated sodium channel. J Biol Chem 2023; 299:105132. [PMID: 37544648 PMCID: PMC10506104 DOI: 10.1016/j.jbc.2023.105132] [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: 02/10/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
Voltage-gated sodium (NaV) channels drive the upstroke of the action potential and are comprised of a pore-forming α-subunit and regulatory β-subunits. The β-subunits modulate the gating, trafficking, and pharmacology of the α-subunit. These functions are routinely assessed by ectopic expression in heterologous cells. However, currently available expression systems may not capture the full range of these effects since they contain endogenous β-subunits. To better reveal β-subunit functions, we engineered a human cell line devoid of endogenous NaV β-subunits and their immediate phylogenetic relatives. This new cell line, β-subunit-eliminated eHAP expression (BeHAPe) cells, were derived from haploid eHAP cells by engineering inactivating mutations in the β-subunits SCN1B, SCN2B, SCN3B, and SCN4B, and other subfamily members MPZ (myelin protein zero(P0)), MPZL1, MPZL2, MPZL3, and JAML. In diploid BeHAPe cells, the cardiac NaV α-subunit, NaV1.5, was highly sensitive to β-subunit modulation and revealed that each β-subunit and even MPZ imparted unique gating properties. Furthermore, combining β1 and β2 with NaV1.5 generated a sodium channel with hybrid properties, distinct from the effects of the individual subunits. Thus, this approach revealed an expanded ability of β-subunits to regulate NaV1.5 activity and can be used to improve the characterization of other α/β NaV complexes.
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Affiliation(s)
- Annabel Y Minard
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States
| | - Colin J Clark
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States.
| | - Robert C Piper
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States.
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Marchal GA, Remme CA. Subcellular diversity of Nav1.5 in cardiomyocytes: distinct functions, mechanisms and targets. J Physiol 2023; 601:941-960. [PMID: 36469003 DOI: 10.1113/jp283086] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/24/2022] [Indexed: 12/11/2022] Open
Abstract
In cardiomyocytes, the rapid depolarisation of the membrane potential is mediated by the α-subunit of the cardiac voltage-gated Na+ channel (NaV 1.5), encoded by the gene SCN5A. This ion channel allows positively charged Na+ ions to enter the cardiomyocyte, resulting in the fast upstroke of the action potential and is therefore crucial for cardiac excitability and electrical propagation. This essential role is underscored by the fact that dysfunctional NaV 1.5 is associated with high risk for arrhythmias and sudden cardiac death. However, development of therapeutic interventions regulating NaV 1.5 has been limited due to the complexity of NaV 1.5 structure and function and its diverse roles within the cardiomyocyte. In particular, research from the last decade has provided us with increased knowledge on the subcellular distribution of NaV 1.5 as well as the proteins which it interacts with in distinct cardiomyocyte microdomains. We here review these insights, detailing the potential role of NaV 1.5 within subcellular domains as well as its dysfunction in the setting of arrhythmia disorders. We furthermore provide an overview of current knowledge on the pathways involved in (microdomain-specific) trafficking of NaV 1.5, and their potential as novel targets. Unravelling the complexity of NaV 1.5 (dys)function may ultimately facilitate the development of therapeutic strategies aimed at preventing lethal arrhythmias. This is not only of importance for pathophysiological conditions where sodium current is specifically decreased within certain subcellular regions, such as in arrhythmogenic cardiomyopathy and Duchenne muscular dystrophy, but also for other acquired and inherited disorders associated with NaV 1.5.
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Affiliation(s)
- Gerard A Marchal
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam UMC location University of Amsterdam, Amsterdam, The Netherlands.,National Institute of Optics, National Research Council (CNR-INO), Sesto Fiorentino, Florence, Italy
| | - Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam UMC location University of Amsterdam, Amsterdam, The Netherlands
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Libiseller-Egger J, Phelan JE, Attia ZI, Benavente ED, Campino S, Friedman PA, Lopez-Jimenez F, Leon DA, Clark TG. Deep learning-derived cardiovascular age shares a genetic basis with other cardiac phenotypes. Sci Rep 2022; 12:22625. [PMID: 36587059 PMCID: PMC9805465 DOI: 10.1038/s41598-022-27254-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023] Open
Abstract
Artificial intelligence (AI)-based approaches can now use electrocardiograms (ECGs) to provide expert-level performance in detecting heart abnormalities and diagnosing disease. Additionally, patient age predicted from ECGs by AI models has shown great potential as a biomarker for cardiovascular age, where recent work has found its deviation from chronological age ("delta age") to be associated with mortality and co-morbidities. However, despite being crucial for understanding underlying individual risk, the genetic underpinning of delta age is unknown. In this work we performed a genome-wide association study using UK Biobank data (n=34,432) and identified eight loci associated with delta age ([Formula: see text]), including genes linked to cardiovascular disease (CVD) (e.g. SCN5A) and (heart) muscle development (e.g. TTN). Our results indicate that the genetic basis of cardiovascular ageing is predominantly determined by genes directly involved with the cardiovascular system rather than those connected to more general mechanisms of ageing. Our insights inform the epidemiology of CVD, with implications for preventative and precision medicine.
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Affiliation(s)
- Julian Libiseller-Egger
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Jody E Phelan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Zachi I Attia
- Department of Cardiovascular Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Paul A Friedman
- Department of Cardiovascular Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | | | - David A Leon
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
- Department of Community Medicine, UiT the Arctic University of Norway, Tromsø, Norway
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK.
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Yoon J, Daneshgar N, Chu Y, Chen B, Hefti M, Vikram A, Irani K, Song L, Brenner C, Abel ED, London B, Dai D. Metabolic rescue ameliorates mitochondrial encephalo-cardiomyopathy in murine and human iPSC models of Leigh syndrome. Clin Transl Med 2022; 12:e954. [PMID: 35872650 PMCID: PMC9309541 DOI: 10.1002/ctm2.954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/09/2022] [Accepted: 06/15/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Mice with deletion of complex I subunit Ndufs4 develop mitochondrial encephalomyopathy resembling Leigh syndrome (LS). The metabolic derangement and underlying mechanisms of cardio-encephalomyopathy in LS remains incompletely understood. METHODS We performed echocardiography, electrophysiology, confocal microscopy, metabolic and molecular/morphometric analysis of the mice lacking Ndufs4. HEK293 cells, human iPS cells-derived cardiomyocytes and neurons were used to determine the mechanistic role of mitochondrial complex I deficiency. RESULTS LS mice develop severe cardiac bradyarrhythmia and diastolic dysfunction. Human-induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) with Ndufs4 deletion recapitulate LS cardiomyopathy. Mechanistically, we demonstrate a direct link between complex I deficiency, decreased intracellular (nicotinamide adenine dinucleotide) NAD+ /NADH and bradyarrhythmia, mediated by hyperacetylation of the cardiac sodium channel NaV 1.5, particularly at K1479 site. Neuronal apoptosis in the cerebellar and midbrain regions in LS mice was associated with hyperacetylation of p53 and activation of microglia. Targeted metabolomics revealed increases in several amino acids and citric acid cycle intermediates, likely due to impairment of NAD+ -dependent dehydrogenases, and a substantial decrease in reduced Glutathione (GSH). Metabolic rescue by nicotinamide riboside (NR) supplementation increased intracellular NAD+ / NADH, restored metabolic derangement, reversed protein hyperacetylation through NAD+ -dependent Sirtuin deacetylase, and ameliorated cardiomyopathic phenotypes, concomitant with improvement of NaV 1.5 current and SERCA2a function measured by Ca2+ -transients. NR also attenuated neuronal apoptosis and microglial activation in the LS brain and human iPS-derived neurons with Ndufs4 deletion. CONCLUSIONS Our study reveals direct mechanistic explanations of the observed cardiac bradyarrhythmia, diastolic dysfunction and neuronal apoptosis in mouse and human induced pluripotent stem cells (iPSC) models of LS.
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Affiliation(s)
- Jin‐Young Yoon
- Division of Cardiovascular Medicine, Department of Internal MedicineUniversity of Iowa Carver College of MedicineIowa CityIowaUSA
- Abboud Cardiovascular Research Center, University of Iowa Carver College of MedicineIowa CityIowaUSA
| | - Nastaran Daneshgar
- Department of Pathology, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
| | - Yi Chu
- Department of Pathology, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal MedicineUniversity of Iowa Carver College of MedicineIowa CityIowaUSA
- Abboud Cardiovascular Research Center, University of Iowa Carver College of MedicineIowa CityIowaUSA
| | - Marco Hefti
- Department of Pathology, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
| | - Ajit Vikram
- Division of Cardiovascular Medicine, Department of Internal MedicineUniversity of Iowa Carver College of MedicineIowa CityIowaUSA
| | - Kaikobad Irani
- Division of Cardiovascular Medicine, Department of Internal MedicineUniversity of Iowa Carver College of MedicineIowa CityIowaUSA
- Abboud Cardiovascular Research Center, University of Iowa Carver College of MedicineIowa CityIowaUSA
| | - Long‐Sheng Song
- Division of Cardiovascular Medicine, Department of Internal MedicineUniversity of Iowa Carver College of MedicineIowa CityIowaUSA
- Abboud Cardiovascular Research Center, University of Iowa Carver College of MedicineIowa CityIowaUSA
| | - Charles Brenner
- Department of Diabetes & Cancer MetabolismCity of Hope National Medical CenterDuarteCaliforniaUSA
| | - E. Dale Abel
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Department of Internal MedicineUniversity of Iowa Carver College of Medicine, University of IowaIowa CityIowaUSA
| | - Barry London
- Division of Cardiovascular Medicine, Department of Internal MedicineUniversity of Iowa Carver College of MedicineIowa CityIowaUSA
- Abboud Cardiovascular Research Center, University of Iowa Carver College of MedicineIowa CityIowaUSA
| | - Dao‐Fu Dai
- Department of Pathology, Carver College of MedicineUniversity of IowaIowa CityIowaUSA
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Abramochkin DV, Filatova TS, Pustovit KB, Voronina YA, Kuzmin VS, Vornanen M. Ionic currents underlying different patterns of electrical activity in working cardiac myocytes of mammals and non-mammalian vertebrates. Comp Biochem Physiol A Mol Integr Physiol 2022; 268:111204. [PMID: 35346823 DOI: 10.1016/j.cbpa.2022.111204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 12/19/2022]
Abstract
The orderly contraction of the vertebrate heart is determined by generation and propagation of cardiac action potentials (APs). APs are generated by the integrated activity of time- and voltage-dependent ionic channels which carry inward Na+ and Ca2+ currents, and outward K+ currents. This review compares atrial and ventricular APs and underlying ion currents between different taxa of vertebrates. We have collected literature data and attempted to find common electrophysiological features for two or more vertebrate groups, show differences between taxa and cardiac chambers, and indicate gaps in the existing data. Although electrical excitability of the heart in all vertebrates is based on the same superfamily of channels, there is a vast variability of AP waveforms between atrial and ventricular myocytes, between different species of the same vertebrate class and between endothermic and ectothermic animals. The wide variability of AP shapes is related to species-specific differences in animal size, heart rate, stage of ontogenetic development, excitation-contraction coupling, temperature and oxygen availability. Some of the differences between taxa are related to evolutionary development of genomes, which appear e.g. in the expression of different Na+ and K+ channel orthologues in cardiomyocytes of vertebrates. There is a wonderful variability of AP shapes and underlying ion currents with which electrical excitability of vertebrate heart can be generated depending on the intrinsic and extrinsic conditions of animal body. This multitude of ionic mechanisms provides excellent material for studying how the function of the vertebrate heart can adapt or acclimate to prevailing physiological and environmental conditions.
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Affiliation(s)
- Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia.
| | - Tatiana S Filatova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
| | - Ksenia B Pustovit
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
| | - Yana A Voronina
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia; Laboratory of Cardiac Electrophysiology, National Medical Research Center for Cardiology, 3(rd) Cherepkovskaya str., 15A, Moscow, Russia
| | - Vladislav S Kuzmin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia; Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova str., 1, Moscow, Russia
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
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Wehrens M, de Leeuw AE, Wright-Clark M, Eding JEC, Boogerd CJ, Molenaar B, van der Kraak PH, Kuster DWD, van der Velden J, Michels M, Vink A, van Rooij E. Single-cell transcriptomics provides insights into hypertrophic cardiomyopathy. Cell Rep 2022; 39:110809. [PMID: 35545053 DOI: 10.1016/j.celrep.2022.110809] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/25/2022] [Accepted: 04/21/2022] [Indexed: 11/24/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a genetic heart disease that is characterized by unexplained segmental hypertrophy that is usually most pronounced in the septum. While sarcomeric gene mutations are often the genetic basis for HCM, the mechanistic origin for the heterogeneous remodeling remains largely unknown. A better understanding of the gene networks driving the cardiomyocyte (CM) hypertrophy is required to improve therapeutic strategies. Patients suffering from HCM often receive a septal myectomy surgery to relieve outflow tract obstruction due to hypertrophy. Using single-cell RNA sequencing (scRNA-seq) on septal myectomy samples from patients with HCM, we identify functional links between genes, transcription factors, and cell size relevant for HCM. The data show the utility of using scRNA-seq on the human hypertrophic heart, highlight CM heterogeneity, and provide a wealth of insights into molecular events involved in HCM that can eventually contribute to the development of enhanced therapies.
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Affiliation(s)
- Martijn Wehrens
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, the Netherlands
| | - Anne E de Leeuw
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, the Netherlands
| | - Maya Wright-Clark
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, the Netherlands; Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Joep E C Eding
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, the Netherlands
| | - Cornelis J Boogerd
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, the Netherlands
| | - Bas Molenaar
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, the Netherlands
| | - Petra H van der Kraak
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Michelle Michels
- Department of Cardiology, Erasmus MC, Rotterdam, the Netherlands
| | - Aryan Vink
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Eva van Rooij
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, the Netherlands; Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands.
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Yin J, Zhou J, Chen J, Xu T, Zhang Z, Zhang H, Yuan C, Cheng X, Qin Y, Zheng B, Wang C, Yang S, Jia Z. Case Report: A Novel Variant c.2262+3A>T of the SCN5A Gene Results in Intron Retention Associated With Incessant Ventricular Tachycardias. Front Med (Lausanne) 2021; 8:659119. [PMID: 34422849 PMCID: PMC8371685 DOI: 10.3389/fmed.2021.659119] [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: 01/27/2021] [Accepted: 06/30/2021] [Indexed: 11/18/2022] Open
Abstract
Objective: Voltage-gated sodium channel Nav1.5 encoded by the SCN5A gene plays crucial roles in cardiac electrophysiology. Previous genetic studies have shown that mutations in SCN5A are associated with multiple inherited cardiac arrhythmias. Here, we investigated the molecular defect in a Chinese boy with clinical manifestations of arrhythmias. Methods: Gene variations were screened using whole-exome sequencing and validated by direct Sanger sequencing. A minigene assay and reverse transcription PCR (RT-PCR) were performed to confirm the effects of splice variants in vitro. Western blot analysis was carried out to determine whether the c.2262+3A>T variant produced a truncated protein. Results: By genetic analysis, we identified a novel splice variant c.2262+3A>T in SCN5A gene in a Chinese boy with incessant ventricular tachycardias (VT). This variant was predicted to activate a new cryptic splice donor site and was identified by in silico analysis. The variant retained 79 bp at the 5′ end of intron 14 in the mature mRNA. Furthermore, the mutant transcript that created a premature stop codon at 818 amino acids [p.(R818*)] could be produced as a truncated protein. Conclusion: We verified the pathogenic effect of splicing variant c.2262+3A>T, which disturbed the normal mRNA splicing and caused a truncated protein, suggesting that splice variants play an important role in the molecular basis of early onset incessant ventricular tachycardias, and careful molecular profiling of these patients will be essential for future effective personalized treatment options.
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Affiliation(s)
- Jie Yin
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jia Zhou
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jinlong Chen
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Ting Xu
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhongman Zhang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Han Zhang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Chang Yuan
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Xueying Cheng
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Yuming Qin
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Chunli Wang
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Shiwei Yang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
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11
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Rivaud MR, Delmar M, Remme CA. Heritable arrhythmia syndromes associated with abnormal cardiac sodium channel function: ionic and non-ionic mechanisms. Cardiovasc Res 2021; 116:1557-1570. [PMID: 32251506 PMCID: PMC7341171 DOI: 10.1093/cvr/cvaa082] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/01/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022] Open
Abstract
The cardiac sodium channel NaV1.5, encoded by the SCN5A gene, is responsible for the fast upstroke of the action potential. Mutations in SCN5A may cause sodium channel dysfunction by decreasing peak sodium current, which slows conduction and facilitates reentry-based arrhythmias, and by enhancing late sodium current, which prolongs the action potential and sets the stage for early afterdepolarization and arrhythmias. Yet, some NaV1.5-related disorders, in particular structural abnormalities, cannot be directly or solely explained on the basis of defective NaV1.5 expression or biophysics. An emerging concept that may explain the large disease spectrum associated with SCN5A mutations centres around the multifunctionality of the NaV1.5 complex. In this alternative view, alterations in NaV1.5 affect processes that are independent of its canonical ion-conducting role. We here propose a novel classification of NaV1.5 (dys)function, categorized into (i) direct ionic effects of sodium influx through NaV1.5 on membrane potential and consequent action potential generation, (ii) indirect ionic effects of sodium influx on intracellular homeostasis and signalling, and (iii) non-ionic effects of NaV1.5, independent of sodium influx, through interactions with macromolecular complexes within the different microdomains of the cardiomyocyte. These indirect ionic and non-ionic processes may, acting alone or in concert, contribute significantly to arrhythmogenesis. Hence, further exploration of these multifunctional effects of NaV1.5 is essential for the development of novel preventive and therapeutic strategies.
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Affiliation(s)
- Mathilde R Rivaud
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam UMC (location AMC), University of Amsterdam, Amsterdam Cardiovascular Sciences, Meigberdreef 15, 1105AZ Amsterdam, The Netherlands
| | - Mario Delmar
- The Leon H. Charney Division of Cardiology, New York University School of Medicine, 435 E 30th St, NSB 707, New York, NY 10016, USA
| | - Carol Ann Remme
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam UMC (location AMC), University of Amsterdam, Amsterdam Cardiovascular Sciences, Meigberdreef 15, 1105AZ Amsterdam, The Netherlands
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12
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Al Sayed ZR, Canac R, Cimarosti B, Bonnard C, Gourraud JB, Hamamy H, Kayserili H, Girardeau A, Jouni M, Jacob N, Gaignerie A, Chariau C, David L, Forest V, Marionneau C, Charpentier F, Loussouarn G, Lamirault G, Reversade B, Zibara K, Lemarchand P, Gaborit N. Human model of IRX5 mutations reveals key role for this transcription factor in ventricular conduction. Cardiovasc Res 2021; 117:2092-2107. [PMID: 32898233 DOI: 10.1093/cvr/cvaa259] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/15/2020] [Accepted: 08/28/2020] [Indexed: 01/02/2023] Open
Abstract
AIMS Several inherited arrhythmic diseases have been linked to single gene mutations in cardiac ion channels and interacting proteins. However, the mechanisms underlying most arrhythmias, are thought to involve altered regulation of the expression of multiple effectors. In this study, we aimed to examine the role of a transcription factor (TF) belonging to the Iroquois homeobox family, IRX5, in cardiac electrical function. METHODS AND RESULTS Using human cardiac tissues, transcriptomic correlative analyses between IRX5 and genes involved in cardiac electrical activity showed that in human ventricular compartment, IRX5 expression strongly correlated to the expression of major actors of cardiac conduction, including the sodium channel, Nav1.5, and Connexin 40 (Cx40). We then generated human-induced pluripotent stem cells (hiPSCs) derived from two Hamamy syndrome-affected patients carrying distinct homozygous loss-of-function mutations in IRX5 gene. Cardiomyocytes derived from these hiPSCs showed impaired cardiac gene expression programme, including misregulation in the control of Nav1.5 and Cx40 expression. In accordance with the prolonged QRS interval observed in Hamamy syndrome patients, a slower ventricular action potential depolarization due to sodium current reduction was observed on electrophysiological analyses performed on patient-derived cardiomyocytes, confirming the functional role of IRX5 in electrical conduction. Finally, a cardiac TF complex was newly identified, composed by IRX5 and GATA4, in which IRX5 potentiated GATA4-induction of SCN5A expression. CONCLUSION Altogether, this work unveils a key role for IRX5 in the regulation of human ventricular depolarization and cardiac electrical conduction, providing therefore new insights into our understanding of cardiac diseases.
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Affiliation(s)
- Zeina R Al Sayed
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Robin Canac
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Bastien Cimarosti
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Carine Bonnard
- Institute of Medical Biology, A*STAR, 8A Biomedical Grove, Singapore 138648, Singapore
| | - Jean-Baptiste Gourraud
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Hanan Hamamy
- Department of Genetic Medicine and Development, Geneva University, 1 rue Michel-Servet, Geneva 1211, Switzerland
| | - Hulya Kayserili
- Medical Genetics Department, Koç University School of Medicine(KUSOM), Rumelifeneri Yolu 34450, Istanbul, Turkey
| | - Aurore Girardeau
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Mariam Jouni
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Nicolas Jacob
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Anne Gaignerie
- Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, 8 Quai Moncousu, F-44000 Nantes, France
| | - Caroline Chariau
- Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, 8 Quai Moncousu, F-44000 Nantes, France
| | - Laurent David
- Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, 8 Quai Moncousu, F-44000 Nantes, France
- Université de Nantes, INSERM, CRTI, 30 Bd Jean Monnet, F-44093 Nantes, France
- ITUN, CHU Nantes, 30 Bd Jean Monnet, F-44093 Nantes, France
| | - Virginie Forest
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Céline Marionneau
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Flavien Charpentier
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Gildas Loussouarn
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Guillaume Lamirault
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Bruno Reversade
- Institute of Medical Biology, A*STAR, 8A Biomedical Grove, Singapore 138648, Singapore
- Medical Genetics Department, Koç University School of Medicine(KUSOM), Rumelifeneri Yolu 34450, Istanbul, Turkey
- Department of Paediatrics, National University of Singapore, 1E Kent Ridge Road, Singapore 119228, Singapore
- Institute of Molecular and Cellular Biology, A*STAR, 61 Biopolis Drive, Singapore 138673, Singapore
- Reproductive Biology Laboratory, Amsterdam UMC, Meibergdreef 9 1105, Amsterdam-Zuidoost, Netherlands
| | - Kazem Zibara
- ER045, Laboratory of stem cells, DSST, Biology department, Faculty of Sciences, Lebanese University, Rafic Hariri Campus - Hadath, Beirut 1700, Lebanon
| | - Patricia Lemarchand
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
| | - Nathalie Gaborit
- Université de Nantes, CNRS, INSERM, l'institut du thorax, 8 quai Moncousu, F-44000 Nantes, France
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13
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Modelling of an autonomous Nav1.5 channel system as a part of in silico pharmacology study. J Mol Model 2021; 27:182. [PMID: 34031769 DOI: 10.1007/s00894-021-04799-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 05/17/2021] [Indexed: 12/22/2022]
Abstract
A homology model of Nav1.5, based mainly on the crystal structures of Nav1.2/1.5 was built, optimized and successfully inserted into the membrane bilayer. We applied steered and free MD simulation protocols for the visualization of the mechanism of Nav1.5 activation. We constrained dihedrals of S4 trigger to introduce a structural tension with further rearrangement and movement of secondary structure elements. From these, we observed an intracellular gate opening and movement of the Lys1419 residue caused by a gradual displacement of the distal S6 α-helix with the extended S4 3-10 helix of voltage-sensing domains (VSD). A construction containing the Lys1419 residue in P-loop also changed its position due to the extension of this helix and subsequent induction of the pore-forming helixes motion. From this point, a double membrane system was generated, implying a free of ligand Nav1.5 protein and on the opposite side its copy containing a docked bupivacaine molecule inside the pore channel. The system can be used for the design of selective inhibitors against the Nav1.7 channel, instead of mixed effect on both channels.
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14
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A Framework for the generation of digital twins of cardiac electrophysiology from clinical 12-leads ECGs. Med Image Anal 2021; 71:102080. [PMID: 33975097 DOI: 10.1016/j.media.2021.102080] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/15/2021] [Accepted: 04/06/2021] [Indexed: 12/21/2022]
Abstract
Cardiac digital twins (Cardiac Digital Twin (CDT)s) of human electrophysiology (Electrophysiology (EP)) are digital replicas of patient hearts derived from clinical data that match like-for-like all available clinical observations. Due to their inherent predictive potential, CDTs show high promise as a complementary modality aiding in clinical decision making and also in the cost-effective, safe and ethical testing of novel EP device therapies. However, current workflows for both the anatomical and functional twinning phases within CDT generation, referring to the inference of model anatomy and parameters from clinical data, are not sufficiently efficient, robust and accurate for advanced clinical and industrial applications. Our study addresses three primary limitations impeding the routine generation of high-fidelity CDTs by introducing; a comprehensive parameter vector encapsulating all factors relating to the ventricular EP; an abstract reference frame within the model allowing the unattended manipulation of model parameter fields; a novel fast-forward electrocardiogram (Electrocardiogram (ECG)) model for efficient and bio-physically-detailed simulation required for parameter inference. A novel workflow for the generation of CDTs is then introduced as an initial proof of concept. Anatomical twinning was performed within a reasonable time compatible with clinical workflows (<4h) for 12 subjects from clinically-attained magnetic resonance images. After assessment of the underlying fast forward ECG model against a gold standard bidomain ECG model, functional twinning of optimal parameters according to a clinically-attained 12 lead ECG was then performed using a forward Saltelli sampling approach for a single subject. The achieved results in terms of efficiency and fidelity demonstrate that our workflow is well-suited and viable for generating biophysically-detailed CDTs at scale.
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15
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Al Kury LT, Sydorenko V, Smail MMA, Qureshi MA, Shmygol A, Papandreou D, Singh J, Howarth FC. Calcium signaling in endocardial and epicardial ventricular myocytes from streptozotocin-induced diabetic rats. J Diabetes Investig 2021; 12:493-500. [PMID: 33112506 PMCID: PMC8015823 DOI: 10.1111/jdi.13451] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/08/2020] [Accepted: 10/22/2020] [Indexed: 12/16/2022] Open
Abstract
AIMS/INTRODUCTION Abnormalities in Ca2+ signaling have a key role in hemodynamic dysfunction in diabetic heart. The purpose of this study was to explore the effects of streptozotocin (STZ)-induced diabetes on Ca2+ signaling in epicardial (EPI) and endocardial (ENDO) cells of the left ventricle after 5-6 months of STZ injection. MATERIALS AND METHODS Whole-cell patch clamp was used to measure the L-type Ca2+ channel (LTCC) and Na+ /Ca2+ exchanger currents. Fluorescence photometry techniques were used to measure intracellular free Ca2+ concentration. RESULTS Although the LTCC current was not significantly altered, the amplitude of Ca2+ transients increased significantly in EPI-STZ and ENDO-STZ compared with controls. Time to peak LTCC current, time to peak Ca2+ transient, time to half decay of LTCC current and time to half decay of Ca2+ transients were not significantly changed in EPI-STZ and ENDO-STZ myocytes compared with controls. The Na+ /Ca2+ exchanger current was significantly smaller in EPI-STZ and in ENDO-STZ compared with controls. CONCLUSIONS STZ-induced diabetes resulted in an increase in amplitude of Ca2+ transients in EPI and ENDO myocytes that was independent of the LTCC current. Such an effect can be attributed, at least in part, to the dysfunction of the Na+ /Ca2+ exchanger. Additional studies are warranted to improve our understanding of the regional impact of diabetes on Ca2+ signaling, which will facilitate the discovery of new targeted treatments for diabetic cardiomyopathy.
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Affiliation(s)
- Lina T Al Kury
- Department of Health SciencesCollege of Natural and Health SciencesZayed UniversityAbu DhabiUnited Arab Emirates
| | - Vadym Sydorenko
- Department of Cellular MembranologyBogomoletz Institute of PhysiologyKievUkraine
| | - Manal MA Smail
- Department of PhysiologyCollege of Medicine and Health SciencesUAE UniversityAl AinUnited Arab Emirates
| | - Muhammad A Qureshi
- Department of PhysiologyCollege of Medicine and Health SciencesUAE UniversityAl AinUnited Arab Emirates
| | - Anatoly Shmygol
- Department of PhysiologyCollege of Medicine and Health SciencesUAE UniversityAl AinUnited Arab Emirates
| | - Dimitrios Papandreou
- Department of Health SciencesCollege of Natural and Health SciencesZayed UniversityAbu DhabiUnited Arab Emirates
| | - Jaipaul Singh
- School of Forensic and Applied SciencesUniversity of Central LancashirePrestonUK
| | - Frank Christopher Howarth
- Department of PhysiologyCollege of Medicine and Health SciencesUAE UniversityAl AinUnited Arab Emirates
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16
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Touat-Hamici Z, Blancard M, Ma R, Lin L, Iddir Y, Denjoy I, Leenhardt A, Yuchi Z, Guicheney P. A SPRY1 domain cardiac ryanodine receptor variant associated with short-coupled torsade de pointes. Sci Rep 2021; 11:5243. [PMID: 33664309 PMCID: PMC7970841 DOI: 10.1038/s41598-021-84373-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 02/03/2021] [Indexed: 12/15/2022] Open
Abstract
Idiopathic ventricular fibrillation (IVF) causes sudden death in young adult patients without structural or ischemic heart disease. Most IVF cases are sporadic and some patients present with short-coupled torsade de pointes, the genetics of which are poorly understood. A man who had a first syncope at the age of 35 presented with frequent short-coupled premature ventricular beats with bursts of polymorphic ventricular tachycardia and then died suddenly. By exome sequencing, we identified three rare variants: p.I784F in the SPRY1 of the ryanodine receptor 2 (RyR2), p.A96S in connexin 40 (Cx40), reported to affect electrical coupling and cardiac conduction, and a nonsense p.R244X in the cardiac-specific troponin I-interacting kinase (TNNI3K). We assessed intracellular Ca2+ handling in WT and mutant human RYR2 transfected HEK293 cells by fluorescent microscopy and an enhanced store overload-induced Ca2+ release in response to cytosolic Ca2+ was observed in RyR2-I784F cells. In addition, crystal structures and thermal melting temperatures revealed a conformational change in the I784F-SPRY1 domain compared to the WT-domain. The novel RyR2-I784F variant in SPRY1 domain causes a leaky channel under non-stress conditions. The presence of several variants affecting Ca2+ handling and cardiac conduction suggests a possible oligogenic origin for the ectopies originating from Purkinje fibres.
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Affiliation(s)
- Zahia Touat-Hamici
- INSERM, UMRS 1166, Faculté de Médecine Sorbonne-Université, Unité de Recherche sur les Maladies Cardiovasculaires et Métaboliques, 91, boulevard de l'Hôpital, 75013, Paris, France
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Paris, France
| | - Malorie Blancard
- INSERM, UMRS 1166, Faculté de Médecine Sorbonne-Université, Unité de Recherche sur les Maladies Cardiovasculaires et Métaboliques, 91, boulevard de l'Hôpital, 75013, Paris, France
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Paris, France
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ruifang Ma
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Lianyun Lin
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Yasmine Iddir
- INSERM, UMRS 1166, Faculté de Médecine Sorbonne-Université, Unité de Recherche sur les Maladies Cardiovasculaires et Métaboliques, 91, boulevard de l'Hôpital, 75013, Paris, France
- Département d'Oncologie Pédiatrique Laboratoire RTOP «Recherche Translationnelle en Oncologie Pédiatrique»-INSERM U830, Institut Curie, Paris, France
| | - Isabelle Denjoy
- Département de Cardiologie et Centre de Référence des Maladies Cardiaques Héréditaires, AP-HP, Hôpital Bichat, 75018, Paris, France
- Université de Paris, INSERM, U1166, 75013, Paris, France
| | - Antoine Leenhardt
- Département de Cardiologie et Centre de Référence des Maladies Cardiaques Héréditaires, AP-HP, Hôpital Bichat, 75018, Paris, France
- Université de Paris, INSERM, U1166, 75013, Paris, France
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
| | - Pascale Guicheney
- INSERM, UMRS 1166, Faculté de Médecine Sorbonne-Université, Unité de Recherche sur les Maladies Cardiovasculaires et Métaboliques, 91, boulevard de l'Hôpital, 75013, Paris, France.
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Paris, France.
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17
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Bhattacharyya S, Munshi NV. Development of the Cardiac Conduction System. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a037408. [PMID: 31988140 DOI: 10.1101/cshperspect.a037408] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cardiac conduction system initiates and propagates each heartbeat. Specialized conducting cells are a well-conserved phenomenon across vertebrate evolution, although mammalian and avian species harbor specific components unique to organisms with four-chamber hearts. Early histological studies in mammals provided evidence for a dominant pacemaker within the right atrium and clarified the existence of the specialized muscular axis responsible for atrioventricular conduction. Building on these seminal observations, contemporary genetic techniques in a multitude of model organisms has characterized the developmental ontogeny, gene regulatory networks, and functional importance of individual anatomical compartments within the cardiac conduction system. This review describes in detail the transcriptional and regulatory networks that act during cardiac conduction system development and homeostasis with a particular emphasis on networks implicated in human electrical variation by large genome-wide association studies. We conclude with a discussion of the clinical implications of these studies and describe some future directions.
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Affiliation(s)
| | - Nikhil V Munshi
- Department of Internal Medicine, Division of Cardiology.,McDermott Center for Human Growth and Development.,Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA.,Hamon Center for Regenerative Science and Medicine, Dallas, Texas 75390, USA
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18
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Grandits T, Gillette K, Neic A, Bayer J, Vigmond E, Pock T, Plank G. An Inverse Eikonal Method for Identifying Ventricular Activation Sequences from Epicardial Activation Maps. JOURNAL OF COMPUTATIONAL PHYSICS 2020; 419:109700. [PMID: 32952215 PMCID: PMC7116090 DOI: 10.1016/j.jcp.2020.109700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A key mechanism controlling cardiac function is the electrical activation sequence of the heart's main pumping chambers termed the ventricles. As such, personalization of the ventricular activation sequences is of pivotal importance for the clinical utility of computational models of cardiac electrophysiology. However, a direct observation of the activation sequence throughout the ventricular volume is virtually impossible. In this study, we report on a novel method for identification of activation sequences from activation maps measured at the outer surface of the heart termed the epicardium. Conceptually, the method attempts to identify the key factors governing the ventricular activation sequence - the timing of earliest activation sites (EAS) and the velocity tensor field within the ventricular walls - from sparse and noisy activation maps sampled from the epicardial surface and fits an Eikonal model to the observations. Regularization methods are first investigated to overcome the severe ill-posedness of the inverse problem in a simplified 2D example. These methods are then employed in an anatomically accurate biventricular model with two realistic activation models of varying complexity - a simplified trifascicular model (3F) and a topologically realistic model of the His-Purkinje system (HPS). Using epicardial activation maps at full resolution, we first demonstrate that reconstructing the volumetric activation sequence is, in principle, feasible under the assumption of known location of EAS and later evaluate robustness of the method against noise and reduced spatial resolution of observations. Our results suggest that the FIMIN algorithm is able to robustly recover the full 3D activation sequence using epicardial activation maps at a spatial resolution achievable with current mapping systems and in the presence of noise. Comparing the accuracy achieved in the reconstructed activation maps with clinical data uncertainties suggests that the FIMIN method may be suitable for the patient- specific parameterization of activation models.
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Affiliation(s)
- Thomas Grandits
- Institute of Computer Graphics and Vision, Graz University of Technology
- BioTechMed-Graz, Austria
| | - Karli Gillette
- Institute of Biophysics, Medical University of Graz
- BioTechMed-Graz, Austria
| | - Aurel Neic
- Institute of Biophysics, Medical University of Graz
| | - Jason Bayer
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac-Bordeaux
| | - Edward Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac-Bordeaux
| | - Thomas Pock
- Institute of Computer Graphics and Vision, Graz University of Technology
- BioTechMed-Graz, Austria
| | - Gernot Plank
- Institute of Biophysics, Medical University of Graz
- BioTechMed-Graz, Austria
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19
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Ribeiro da Silva A, Neri EA, Turaça LT, Dariolli R, Fonseca-Alaniz MH, Santos-Miranda A, Roman-Campos D, Venturini G, Krieger JE. NOTCH1 is critical for fibroblast-mediated induction of cardiomyocyte specialization into ventricular conduction system-like cells in vitro. Sci Rep 2020; 10:16163. [PMID: 32999360 PMCID: PMC7527973 DOI: 10.1038/s41598-020-73159-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiac fibroblasts are present throughout the myocardium and are enriched in the microenvironment surrounding the ventricular conduction system (VCS). Several forms of arrhythmias are linked to VCS abnormalities, but it is still unclear whether VCS malformations are cardiomyocyte autonomous or could be linked to crosstalk between different cell types. We reasoned that fibroblasts influence cardiomyocyte specialization in VCS cells. We developed 2D and 3D culture models of neonatal rat cardiac cells to assess the influence of cardiac fibroblasts on cardiomyocytes. Cardiomyocytes adjacent to cardiac fibroblasts showed a two-fold increase in expression of VCS markers (NAV1.5 and CONTACTIN 2) and calcium transient duration, displaying a Purkinje-like profile. Fibroblast-conditioned media (fCM) was sufficient to activate VCS-related genes (Irx3, Scn5a, Connexin 40) and to induce action potential prolongation, a hallmark of Purkinge phenotype. fCM-mediated response seemed to be spatially-dependent as cardiomyocyte organoids treated with fCM had increased expression of connexin 40 and NAV1.5 primarily on its outer surface. Finally, NOTCH1 activation in both cardiomyocytes and fibroblasts was required for connexin 40 up-regulation (a proxy of VCS phenotype). Altogether, we provide evidence that cardiac fibroblasts influence cardiomyocyte specialization into VCS-like cells via NOTCH1 signaling in vitro.
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Affiliation(s)
- Agatha Ribeiro da Silva
- Lab Genetics & Molec Cardiology, Instituto do Coracao (InCor) da Faculdade de Medicina da Universidade de Sao Paulo (FMUSP), São Paulo, Brazil
| | - Elida A Neri
- Lab Genetics & Molec Cardiology, Instituto do Coracao (InCor) da Faculdade de Medicina da Universidade de Sao Paulo (FMUSP), São Paulo, Brazil
| | - Lauro Thiago Turaça
- Lab Genetics & Molec Cardiology, Instituto do Coracao (InCor) da Faculdade de Medicina da Universidade de Sao Paulo (FMUSP), São Paulo, Brazil
| | - Rafael Dariolli
- Lab Genetics & Molec Cardiology, Instituto do Coracao (InCor) da Faculdade de Medicina da Universidade de Sao Paulo (FMUSP), São Paulo, Brazil
| | - Miriam H Fonseca-Alaniz
- Lab Genetics & Molec Cardiology, Instituto do Coracao (InCor) da Faculdade de Medicina da Universidade de Sao Paulo (FMUSP), São Paulo, Brazil
| | - Artur Santos-Miranda
- Paulista School of Medicine, Federal University of São Paulo (EPM-UNIFESP), São Paulo, Brazil
| | - Danilo Roman-Campos
- Paulista School of Medicine, Federal University of São Paulo (EPM-UNIFESP), São Paulo, Brazil
| | - Gabriela Venturini
- Lab Genetics & Molec Cardiology, Instituto do Coracao (InCor) da Faculdade de Medicina da Universidade de Sao Paulo (FMUSP), São Paulo, Brazil
| | - Jose E Krieger
- Lab Genetics & Molec Cardiology, Instituto do Coracao (InCor) da Faculdade de Medicina da Universidade de Sao Paulo (FMUSP), São Paulo, Brazil.
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20
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Blok M, Boukens BJ. Mechanisms of Arrhythmias in the Brugada Syndrome. Int J Mol Sci 2020; 21:ijms21197051. [PMID: 32992720 PMCID: PMC7582368 DOI: 10.3390/ijms21197051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 12/13/2022] Open
Abstract
Arrhythmias in Brugada syndrome patients originate in the right ventricular outflow tract (RVOT). Over the past few decades, the characterization of the unique anatomy and electrophysiology of the RVOT has revealed the arrhythmogenic nature of this region. However, the mechanisms that drive arrhythmias in Brugada syndrome patients remain debated as well as the exact site of their occurrence in the RVOT. Identifying the site of origin and mechanism of Brugada syndrome would greatly benefit the development of mechanism-driven treatment strategies.
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Affiliation(s)
- Michiel Blok
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Bastiaan J. Boukens
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Correspondence: ; Tel.: +31-(0)20-566-4659
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21
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Grassam-Rowe A, Ou X, Lei M. Novel cardiac cell subpopulations: Pnmt-derived cardiomyocytes. Open Biol 2020; 10:200095. [PMID: 32810421 PMCID: PMC7479933 DOI: 10.1098/rsob.200095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/29/2020] [Indexed: 11/12/2022] Open
Abstract
Diversity among highly specialized cells underlies the fundamental biology of complex multi-cellular organisms. One of the essential scientific questions in cardiac biology has been to define subpopulations within the heart. The heart parenchyma comprises specialized cardiomyocytes (CMs). CMs have been canonically classified into a few phenotypically diverse subpopulations largely based on their function and anatomic localization. However, there is growing evidence that CM subpopulations are in fact numerous, with a diversity of genetic origin and putatively different roles in physiology and pathophysiology. In this chapter, we introduce a recently discovered CM subpopulation: phenylethanolamine-N-methyl transferase (Pnmt)-derived cardiomyocytes (PdCMs). We discuss: (i) canonical classifications of CM subpopulations; (ii) discovery of PdCMs; (iii) Pnmt and the role of catecholamines in the heart; similarities and dissimilarities of PdCMs and canonical CMs; and (iv) putative functions of PdCMs in both physiological and pathological states and future directions, such as in intra-cardiac adrenergic signalling.
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Affiliation(s)
| | - Xianghong Ou
- Key Laboratory of Medical Electrophysiology of the Ministry of Education and Institute of Cardiovascular Research, Southwest Medical University, Luzhou 6400, People's Republic of China
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
- Key Laboratory of Medical Electrophysiology of the Ministry of Education and Institute of Cardiovascular Research, Southwest Medical University, Luzhou 6400, People's Republic of China
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22
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Mavroidis M, Athanasiadis NC, Rigas P, Kostavasili I, Kloukina I, Te Rijdt WP, Kavantzas N, Chaniotis D, van Tintelen JP, Skaliora I, Davos CH. Desmin is essential for the structure and function of the sinoatrial node: implications for increased arrhythmogenesis. Am J Physiol Heart Circ Physiol 2020; 319:H557-H570. [PMID: 32678709 DOI: 10.1152/ajpheart.00594.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Our objective was to investigate the effect of desmin depletion on the structure and function of the sinoatrial pacemaker complex (SANcl) and its implication in arrhythmogenesis. Analysis of mice and humans (SANcl) indicated that the sinoatrial node exhibits high amounts of desmin, desmoplakin, N-cadherin, and β-catenin in structures we call "lateral intercalated disks" connecting myocytes side by side. Examination of the SANcl from an arrhythmogenic cardiomyopathy model, desmin-deficient (Des-/-) mouse, by immunofluorescence, ultrastructural, and Western blot analysis showed that the number of these lateral intercalated disks was diminished. Also, electrophysiological recordings of the isolated compact sinoatrial node revealed increased pacemaker systolic potential and higher diastolic depolarization rate compared with wild-type mice. Prolonged interatrial conduction expressed as a longer P wave duration was also observed in Des-/- mice. Upregulation of mRNA levels of both T-type Ca2+ current channels, Cav3.1 and Cav3.2, in the Des-/- myocardium (1.8- and 2.3-fold, respectively) and a 1.9-fold reduction of funny hyperpolarization-activated cyclic nucleotide-gated K+ channel 1 could underlie these functional differences. To investigate arrhythmogenicity, electrocardiographic analysis of Des-deficient mice revealed a major increase in supraventricular and ventricular ectopic beats compared with wild-type mice. Heart rate variability analysis indicated a sympathetic predominance in Des-/- mice, which may further contribute to arrhythmogenicity. In conclusion, our results indicate that desmin elimination leads to structural and functional abnormalities of the SANcl. These alterations may be enhanced by the sympathetic component of the cardiac autonomic nervous system, which is predominant in the desmin-deficient heart, thus leading to increased arrhythmogenesis.NEW & NOTEWORTHY The sinoatrial node exhibits high amounts of desmin and desmoplakin in structures we call "lateral intercalated disks," connecting side-by-side adjacent cardiomyocytes. These structures are diminished in desmin-deficient mouse models. Misregulation of T-type Ca2+ current and hyperpolarization-activated cyclic nucleotide-gated K+ channel 1 was proved along with prolonged interatrial conduction and cardiac autonomic nervous system dysfunction.
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Affiliation(s)
- Manolis Mavroidis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Nikolaos C Athanasiadis
- Center of Clinical Research and Experimental Surgery, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Pavlos Rigas
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Ioanna Kostavasili
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Ismini Kloukina
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Wouter P Te Rijdt
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nikolaos Kavantzas
- First Department of Pathology, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitris Chaniotis
- Center of Clinical Research and Experimental Surgery, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - J Peter van Tintelen
- Department of Genetics, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Irini Skaliora
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Constantinos H Davos
- Center of Clinical Research and Experimental Surgery, Biomedical Research Foundation, Academy of Athens, Athens, Greece
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23
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Burnicka-Turek O, Broman MT, Steimle JD, Boukens BJ, Petrenko NB, Ikegami K, Nadadur RD, Qiao Y, Arnolds DE, Yang XH, Patel VV, Nobrega MA, Efimov IR, Moskowitz IP. Transcriptional Patterning of the Ventricular Cardiac Conduction System. Circ Res 2020; 127:e94-e106. [PMID: 32290757 PMCID: PMC8328577 DOI: 10.1161/circresaha.118.314460] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
RATIONALE The heartbeat is organized by the cardiac conduction system (CCS), a specialized network of cardiomyocytes. Patterning of the CCS into atrial node versus ventricular conduction system (VCS) components with distinct physiology is essential for the normal heartbeat. Distinct node versus VCS physiology has been recognized for more than a century, but the molecular basis of this regional patterning is not well understood. OBJECTIVE To study the genetic and genomic mechanisms underlying node versus VCS distinction and investigate rhythm consequences of failed VCS patterning. METHODS AND RESULTS Using mouse genetics, we found that the balance between T-box transcriptional activator, Tbx5, and T-box transcriptional repressor, Tbx3, determined the molecular and functional output of VCS myocytes. Adult VCS-specific removal of Tbx5 or overexpression of Tbx3 re-patterned the fast VCS into slow, nodal-like cells based on molecular and functional criteria. In these cases, gene expression profiling showed diminished expression of genes required for VCS-specific fast conduction but maintenance of expression of genes required for nodal slow conduction physiology. Action potentials of Tbx5-deficient VCS myocytes adopted nodal-specific characteristics, including increased action potential duration and cellular automaticity. Removal of Tbx5 in vivo precipitated inappropriate depolarizations in the atrioventricular (His)-bundle associated with lethal ventricular arrhythmias. TBX5 bound and directly activated cis-regulatory elements at fast conduction channel genes required for fast physiological characteristics of the VCS action potential, defining the identity of the adult VCS. CONCLUSIONS The CCS is patterned entirely as a slow, nodal ground state, with a T-box dependent, physiologically dominant, fast conduction network driven specifically in the VCS. Disruption of the fast VCS gene regulatory network allowed nodal physiology to emerge, providing a plausible molecular mechanism for some lethal ventricular arrhythmias.
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Affiliation(s)
- Ozanna Burnicka-Turek
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Michael T. Broman
- Department of Medicine, The University of Chicago, Chicago, IL, 60637, USA
| | - Jeffrey D. Steimle
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Bastiaan J. Boukens
- Department of Biomedical Engineering, George Washington University, Washington, DC 20052, USA
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Nataliya B. Petrenko
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Penn Cardiovascular Institute, Philadelphia, PA 19104, USA
| | - Kohta Ikegami
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Rangarajan D. Nadadur
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Yun Qiao
- Department of Biomedical Engineering, George Washington University, Washington, DC 20052, USA
| | - David E. Arnolds
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Xinan H. Yang
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Vickas V. Patel
- Discovery Medicine, GlaxoSmithKline, Collegeville, PA 19426, USA
| | - Marcelo A. Nobrega
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Igor R. Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC 20052, USA
| | - Ivan P. Moskowitz
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
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24
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Jensen B, Christoffels VM. Reptiles as a Model System to Study Heart Development. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a037226. [PMID: 31712265 DOI: 10.1101/cshperspect.a037226] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A chambered heart is common to all vertebrates, but reptiles show unparalleled variation in ventricular septation, ranging from almost absent in tuataras to full in crocodilians. Because mammals and birds evolved independently from reptile lineages, studies on reptile development may yield insight into the evolution and development of the full ventricular septum. Compared with reptiles, mammals and birds have evolved several other adaptations, including compact chamber walls and a specialized conduction system. These adaptations appear to have evolved from precursor structures that can be studied in present-day reptiles. The increase in the number of studies on reptile heart development has been greatly facilitated by sequencing of several genomes and the availability of good staging systems. Here, we place reptiles in their phylogenetic context with a focus on features that are primitive when compared with the homologous features of mammals. Further, an outline of major developmental events is given, and variation between reptile species is discussed.
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Affiliation(s)
- Bjarke Jensen
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC 1105AZ, Amsterdam, The Netherlands
| | - Vincent M Christoffels
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC 1105AZ, Amsterdam, The Netherlands
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25
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Doisne N, Waldmann V, Redheuil A, Waintraub X, Fressart V, Ader F, Fossé L, Hidden-Lucet F, Gandjbakhch E, Neyroud N. A novel gain-of-function mutation in SCN5A responsible for multifocal ectopic Purkinje-related premature contractions. Hum Mutat 2020; 41:850-859. [PMID: 31930659 DOI: 10.1002/humu.23981] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 12/13/2019] [Accepted: 01/02/2020] [Indexed: 12/19/2022]
Abstract
Recently, four SCN5A mutations have been associated with Multifocal Ectopic Purkinje-related Premature Contractions (MEPPC), a rare cardiac syndrome combining polymorphic ventricular arrhythmia with dilated cardiomyopathy (DCM). Here, we identified a novel heterozygous mutation in SCN5A (c.611C>A, pAla204Glu) in a young woman presenting with polymorphic premature ventricular contractions (PVCs) and DCM. After failure of antiarrhythmic drugs and an attempt of radiofrequency catheter ablation showing three exit-sites of PVCs, all with presystolic Purkinje potentials, a treatment by hydroquinidine was tried, leading to an immediate and spectacular disappearance of all PVCs and normalization of cardiac function. Electrophysiological studies showed that Nav 1.5-A204E mutant channels exhibited a significant leftward shift of 8 mV of the activation curve, leading to a larger hyperpolarized window current when compared to wild-type. Action potential modeling using Purkinje fiber and ventricular cell models predicted an arrhythmogenic effect predominant in Purkinje fibers for the A204E mutation. Comparison with other MEPPC-associated Nav 1.5 mutations revealed a common electrophysiological pattern of abnormal voltage-dependence of activation leading to a larger hyperpolarized window current as a shared biophysical mechanism of this syndrome. These features of the mutant sodium channels are likely to be responsible for the hyperexcitability of the fascicular-Purkinje system observed in patients with MEPPC.
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Affiliation(s)
- Nicolas Doisne
- Faculté de Médecine, Sorbonne Université, Paris, France.,INSERM, UMR_S1166, Hôpital Pitié-Salpêtrière, Paris, France.,ICAN, Institute of Cardiometabolism and Nutrition, Paris, France
| | - Victor Waldmann
- Département de Cardiologie, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Alban Redheuil
- Faculté de Médecine, Sorbonne Université, Paris, France.,ICAN, Institute of Cardiometabolism and Nutrition, Paris, France.,Département d'Imagerie Cardiovasculaire, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Xavier Waintraub
- ICAN, Institute of Cardiometabolism and Nutrition, Paris, France.,Département de Cardiologie, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Véronique Fressart
- Faculté de Médecine, Sorbonne Université, Paris, France.,INSERM, UMR_S1166, Hôpital Pitié-Salpêtrière, Paris, France.,ICAN, Institute of Cardiometabolism and Nutrition, Paris, France.,Département de Biochimie métabolique, Cardiogénétique, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Flavie Ader
- Faculté de Médecine, Sorbonne Université, Paris, France.,INSERM, UMR_S1166, Hôpital Pitié-Salpêtrière, Paris, France.,ICAN, Institute of Cardiometabolism and Nutrition, Paris, France.,Département de Biochimie métabolique, Cardiogénétique, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Lucie Fossé
- Faculté de Médecine, Sorbonne Université, Paris, France.,INSERM, UMR_S1166, Hôpital Pitié-Salpêtrière, Paris, France
| | - Françoise Hidden-Lucet
- ICAN, Institute of Cardiometabolism and Nutrition, Paris, France.,Département de Cardiologie, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Estelle Gandjbakhch
- Faculté de Médecine, Sorbonne Université, Paris, France.,INSERM, UMR_S1166, Hôpital Pitié-Salpêtrière, Paris, France.,ICAN, Institute of Cardiometabolism and Nutrition, Paris, France.,Département de Cardiologie, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Nathalie Neyroud
- Faculté de Médecine, Sorbonne Université, Paris, France.,INSERM, UMR_S1166, Hôpital Pitié-Salpêtrière, Paris, France.,ICAN, Institute of Cardiometabolism and Nutrition, Paris, France
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26
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Man JCK, Mohan RA, Boogaard MVD, Hilvering CRE, Jenkins C, Wakker V, Bianchi V, Laat WD, Barnett P, Boukens BJ, Christoffels VM. An enhancer cluster controls gene activity and topology of the SCN5A-SCN10A locus in vivo. Nat Commun 2019; 10:4943. [PMID: 31666509 PMCID: PMC6821807 DOI: 10.1038/s41467-019-12856-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 10/03/2019] [Indexed: 12/19/2022] Open
Abstract
Mutations and variations in and around SCN5A, encoding the major cardiac sodium channel, influence impulse conduction and are associated with a broad spectrum of arrhythmia disorders. Here, we identify an evolutionary conserved regulatory cluster with super enhancer characteristics downstream of SCN5A, which drives localized cardiac expression and contains conduction velocity-associated variants. We use genome editing to create a series of deletions in the mouse genome and show that the enhancer cluster controls the conformation of a >0.5 Mb genomic region harboring multiple interacting gene promoters and enhancers. We find that this cluster and its individual components are selectively required for cardiac Scn5a expression, normal cardiac conduction and normal embryonic development. Our studies reveal physiological roles of an enhancer cluster in the SCN5A-SCN10A locus, show that it controls the chromatin architecture of the locus and Scn5a expression, and suggest that genetic variants affecting its activity may influence cardiac function.
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Affiliation(s)
- Joyce C K Man
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands
| | - Rajiv A Mohan
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands
| | - Malou van den Boogaard
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands
| | - Catharina R E Hilvering
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Catherine Jenkins
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands
| | - Vincent Wakker
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands
| | - Valerio Bianchi
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Wouter de Laat
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Phil Barnett
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands
| | - Bastiaan J Boukens
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands
| | - Vincent M Christoffels
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Academic Medical Center, Amsterdam, The Netherlands.
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27
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Abstract
The rate and rhythm of heart muscle contractions are coordinated by the cardiac conduction system (CCS), a generic term for a collection of different specialized muscular tissues within the heart. The CCS components initiate the electrical impulse at the sinoatrial node, propagate it from atria to ventricles via the atrioventricular node and bundle branches, and distribute it to the ventricular muscle mass via the Purkinje fibre network. The CCS thereby controls the rate and rhythm of alternating contractions of the atria and ventricles. CCS function is well conserved across vertebrates from fish to mammals, although particular specialized aspects of CCS function are found only in endotherms (mammals and birds). The development and homeostasis of the CCS involves transcriptional and regulatory networks that act in an embryonic-stage-dependent, tissue-dependent, and dose-dependent manner. This Review describes emerging data from animal studies, stem cell models, and genome-wide association studies that have provided novel insights into the transcriptional networks underlying CCS formation and function. How these insights can be applied to develop disease models and therapies is also discussed.
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Kelly A, Salerno S, Connolly A, Bishop M, Charpentier F, Stølen T, Smith GL. Normal interventricular differences in tissue architecture underlie right ventricular susceptibility to conduction abnormalities in a mouse model of Brugada syndrome. Cardiovasc Res 2019; 114:724-736. [PMID: 29267949 PMCID: PMC5915948 DOI: 10.1093/cvr/cvx244] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/16/2017] [Indexed: 01/09/2023] Open
Abstract
Aims Loss-of-function of the cardiac sodium channel NaV1.5 is a common feature of Brugada syndrome. Arrhythmias arise preferentially from the right ventricle (RV) despite equivalent NaV1.5 downregulation in the left ventricle (LV). The reasons for increased RV sensitivity to NaV1.5 loss-of-function mutations remain unclear. Because ventricular electrical activation occurs predominantly in the transmural axis, we compare RV and LV transmural electrophysiology to determine the underlying cause of the asymmetrical conduction abnormalities in Scn5a haploinsufficient mice (Scn5a+/−). Methods and results Optical mapping and two-photon microscopy in isolated-perfused mouse hearts demonstrated equivalent depression of transmural conduction velocity (CV) in the LV and RV of Scn5a+/− vs. wild-type littermates. Only RV transmural conduction was further impaired when challenged with increased pacing frequencies. Epicardial dispersion of activation and beat-to-beat variation in activation time were increased only in the RV of Scn5a+/− hearts. Analysis of confocal and histological images revealed larger intramural clefts between cardiomyocyte layers in the RV vs. LV, independent of genotype. Acute sodium current inhibition in wild type hearts using tetrodotoxin reproduced beat-to-beat activation variability and frequency-dependent CV slowing in the RV only, with the LV unaffected. The influence of clefts on conduction was examined using a two-dimensional monodomain computational model. When peak sodium channel conductance was reduced to 50% of normal the presence of clefts between cardiomyocyte layers reproduced the activation variability and conduction phenotype observed experimentally. Conclusions Normal structural heterogeneities present in the RV are responsible for increased vulnerability to conduction slowing in the presence of reduced sodium channel function. Heterogeneous conduction slowing seen in the RV will predispose to functional block and the initiation of re-entrant ventricular arrhythmias.
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Affiliation(s)
- Allen Kelly
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway.,Institute of Cardiovascular & Medical Sciences, University of Glasgow G12 8QQ, UK
| | - Simona Salerno
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway
| | - Adam Connolly
- Division of Imaging Sciences and Biomedical Engineering, Department of Biomedical Engineering, Kings College London SE1 7EH, UK
| | - Martin Bishop
- Division of Imaging Sciences and Biomedical Engineering, Department of Biomedical Engineering, Kings College London SE1 7EH, UK
| | | | - Tomas Stølen
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway
| | - Godfrey L Smith
- Department of Circulation and Medical Imaging, St Olav's Hospital, Norwegian University of Science and Technology (NTNU), Postboks 8905, 7491 Trondheim, Norway.,Institute of Cardiovascular & Medical Sciences, University of Glasgow G12 8QQ, UK
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29
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Handa BS, Lawal S, Wright IJ, Li X, Cabello-García J, Mansfield C, Chowdhury RA, Peters NS, Ng FS. Interventricular Differences in Action Potential Duration Restitution Contribute to Dissimilar Ventricular Rhythms in ex vivo Perfused Hearts. Front Cardiovasc Med 2019; 6:34. [PMID: 31001543 PMCID: PMC6456660 DOI: 10.3389/fcvm.2019.00034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/13/2019] [Indexed: 01/24/2023] Open
Abstract
Background: Dissimilar ventricular rhythms refer to the occurrence of different ventricular tachyarrhythmias in the right and left ventricles or different rates of the same tachyarrhythmia in the two ventricles. Objective: We investigated the inducibility of dissimilar ventricular rhythms, their underlying mechanisms, and the impact of anti-arrhythmic drugs (lidocaine and amiodarone) on their occurrence. Methods: Ventricular tachyarrhythmias were induced with burst pacing in 28 Langendorff-perfused Sprague Dawley rat hearts (14 control, 8 lidocaine, 6 amiodarone) and bipolar electrograms recorded from the right and left ventricles. Fourteen (6 control, 4 lidocaine, 4 amiodarone) further hearts underwent optical mapping of transmembrane voltage to study interventricular electrophysiological differences and mechanisms of dissimilar rhythms. Results: In control hearts, dissimilar ventricular rhythms developed in 8/14 hearts (57%). In lidocaine treated hearts, there was a lower cycle length threshold for developing dissimilar rhythms, with 8/8 (100%) hearts developing dissimilar rhythms in comparison to 0/6 in the amiodarone group. Dissimilar ventricular tachycardia (VT) rates occurred at longer cycle lengths with lidocaine vs. control (57.1 ± 7.9 vs. 36.6 ± 8.4 ms, p < 0.001). The ratio of LV:RV VT rate was greater in the lidocaine group than control (1.91 ± 0.30 vs. 1.76 ± 0.36, p < 0.001). The gradient of the action potential duration (APD) restitution curve was shallower in the RV compared with LV (Control - LV: 0.12 ± 0.03 vs RV: 0.002 ± 0.03, p = 0.015), leading to LV-to-RV conduction block during VT. Conclusion: Interventricular differences in APD restitution properties likely contribute to the occurrence of dissimilar rhythms. Sodium channel blockade with lidocaine increases the likelihood of dissimilar ventricular rhythms.
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Affiliation(s)
- Balvinder S. Handa
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Saheed Lawal
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Ian J. Wright
- Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Xinyang Li
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | | | - Catherine Mansfield
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Rasheda A. Chowdhury
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Nicholas S. Peters
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Fu Siong Ng
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Imperial College Healthcare NHS Trust, London, United Kingdom
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30
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Liu X, Chen Z, Han Z, Liu Y, Wu X, Peng Y, Di W, Lan R, Sun B, Xu B, Xu W. AMPK-mediated degradation of Nav1.5 through autophagy. FASEB J 2019; 33:5366-5376. [PMID: 30759345 DOI: 10.1096/fj.201801583rr] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The voltage-gated cardiac sodium channel, Nav1.5, is the key component that controls cardiac excitative electrical impulse and propagation. However, the dynamic alterations of Nav1.5 during cardiac ischemia and reperfusion (I/R) are seldom reported. We found that the protein levels of rat cardiac Nav1.5 were significantly decreased in response to cardiac I/R injury. By simulating I/R injury in cells through activating AMPK by glucose deprivation, AMPK activator treatment, or hypoxia and reoxygenation (H/R), we found that Nav1.5 was down-regulated by AMPK-mediated autophagic degradation. Furthermore, AMPK was found to phosphorylate Nav1.5 at threonine (T) 101, which then regulates the interaction between Nav1.5 and the autophagic adaptor protein, microtubule-associated protein 1 light chain 3 (LC3), by exposing the LC3-interacting region adjacent to T101 in Nav1.5. This study highlights an instrumental role of AMPK in mediating the autophagic degradation of Nav1.5 during cardiac I/R injury.-Liu, X., Chen, Z., Han, Z., Liu, Y., Wu, X., Peng, Y., Di, W., Lan, R., Sun, B., Xu, B., Xu, W. AMPK-mediated degradation of Nav1.5 through autophagy.
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Affiliation(s)
- Xuehua Liu
- Department of Ultrasound Diagnosis, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Zheng Chen
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Zhonglin Han
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yu Liu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Xiang Wu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yuzhu Peng
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Wencheng Di
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Rongfang Lan
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Bugao Sun
- Department of Ultrasound Diagnosis, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Biao Xu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Wei Xu
- Department of Cardiology, Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
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31
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Verkerk AO, Amin AS, Remme CA. Disease Modifiers of Inherited SCN5A Channelopathy. Front Cardiovasc Med 2018; 5:137. [PMID: 30327767 PMCID: PMC6174200 DOI: 10.3389/fcvm.2018.00137] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/10/2018] [Indexed: 12/19/2022] Open
Abstract
To date, a large number of mutations in SCN5A, the gene encoding the pore-forming α-subunit of the primary cardiac Na+ channel (NaV1.5), have been found in patients presenting with a wide range of ECG abnormalities and cardiac syndromes. Although these mutations all affect the same NaV1.5 channel, the associated cardiac syndromes each display distinct phenotypical and biophysical characteristics. Variable disease expressivity has also been reported, where one particular mutation in SCN5A may lead to either one particular symptom, a range of various clinical signs, or no symptoms at all, even within one single family. Additionally, disease severity may vary considerably between patients carrying the same mutation. The exact reasons are unknown, but evidence is increasing that various cardiac and non-cardiac conditions can influence the expressivity and severity of inherited SCN5A channelopathies. In this review, we provide a summary of identified disease entities caused by SCN5A mutations, and give an overview of co-morbidities and other (non)-genetic factors which may modify SCN5A channelopathies. A comprehensive knowledge of these modulatory factors is not only essential for a complete understanding of the diverse clinical phenotypes associated with SCN5A mutations, but also for successful development of effective risk stratification and (alternative) treatment paradigms.
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Affiliation(s)
- Arie O Verkerk
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands.,Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands
| | - Ahmad S Amin
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
| | - Carol Ann Remme
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
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32
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Anderson RH, Mori S, Spicer DE, Sanchez-Quintana D, Jensen B. The Anatomy, Development, and Evolution of the Atrioventricular Conduction Axis. J Cardiovasc Dev Dis 2018; 5:jcdd5030044. [PMID: 30135383 PMCID: PMC6162790 DOI: 10.3390/jcdd5030044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/16/2018] [Accepted: 08/19/2018] [Indexed: 12/22/2022] Open
Abstract
It is now well over 100 years since Sunao Tawara clarified the location of the axis of the specialised myocardium responsible for producing coordinated ventricular activation. Prior to that stellar publication, controversies had raged as to how many bundles crossed the place of the atrioventricular insulation as found in mammalian hearts, as well as the very existence of the bundle initially described by Wilhelm His Junior. It is, perhaps surprising that controversies continue, despite the multiple investigations that have taken place since the publication of Tawara’s monograph. For example, we are still unsure as to the precise substrates for the so-called slow and fast pathways into the atrioventricular node. Much has been done, nonetheless, to characterise the molecular make-up of the specialised pathways, and to clarify their mechanisms of development. Of this work itself, a significant part has emanated from the laboratory coordinated for a quarter of a century by Antoon FM Moorman. In this review, which joins the others in recognising the value of his contributions and collaborations, we review our current understanding of the anatomy, development, and evolution of the atrioventricular conduction axis.
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Affiliation(s)
- Robert H Anderson
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 4EP, UK.
| | - Shumpei Mori
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Hyogo, Japan.
| | - Diane E Spicer
- Department of Pediatric Cardiology, University of Florida, Gainesville, FL 32610, USA.
| | - Damian Sanchez-Quintana
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Extremadura, 06006 Badajoz, Spain.
| | - Bjarke Jensen
- University of Amsterdam, Amsterdam UMC, Department of Medical Biology, Amsterdam Cardiovascular Sciences, Meibergdreef 15, 1105AZ Amsterdam, The Netherlands.
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33
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Shekhar A, Lin X, Lin B, Liu FY, Zhang J, Khodadadi-Jamayran A, Tsirigos A, Bu L, Fishman GI, Park DS. ETV1 activates a rapid conduction transcriptional program in rodent and human cardiomyocytes. Sci Rep 2018; 8:9944. [PMID: 29967479 PMCID: PMC6028599 DOI: 10.1038/s41598-018-28239-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/19/2018] [Indexed: 01/07/2023] Open
Abstract
Rapid impulse propagation is a defining attribute of the pectinated atrial myocardium and His-Purkinje system (HPS) that safeguards against atrial and ventricular arrhythmias, conduction block, and myocardial dyssynchrony. The complex transcriptional circuitry that dictates rapid conduction remains incompletely understood. Here, we demonstrate that ETV1 (ER81)-dependent gene networks dictate the unique electrophysiological characteristics of atrial and His-Purkinje myocytes. Cardiomyocyte-specific deletion of ETV1 results in cardiac conduction abnormalities, decreased expression of rapid conduction genes (Nkx2-5, Gja5, and Scn5a), HPS hypoplasia, and ventricularization of the unique sodium channel properties that define Purkinje and atrial myocytes in the adult heart. Forced expression of ETV1 in postnatal ventricular myocytes (VMs) reveals that ETV1 promotes a HPS gene signature while diminishing ventricular and nodal gene networks. Remarkably, ETV1 induction in human induced pluripotent stem cell-derived cardiomyocytes increases rapid conduction gene expression and inward sodium currents, converting them towards a HPS phenotype. Our data identify a cardiomyocyte-autonomous, ETV1-dependent pathway that is responsible for specification of rapid conduction zones in the heart and demonstrate that ETV1 is sufficient to promote a HPS transcriptional and functional program upon VMs.
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Affiliation(s)
- Akshay Shekhar
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA
| | - Xianming Lin
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA
| | - Bin Lin
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA
| | - Fang-Yu Liu
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA
| | - Jie Zhang
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA
| | - Alireza Khodadadi-Jamayran
- Center for Health Informatics and Bioinformatics, New York University Langone Health, New York, New York, 10016, USA
| | - Aristotelis Tsirigos
- Center for Health Informatics and Bioinformatics, New York University Langone Health, New York, New York, 10016, USA
| | - Lei Bu
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA
| | - Glenn I Fishman
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA.
| | - David S Park
- Leon H. Charney Division of Cardiology, New York University Langone Health, New York, New York, 10016, USA.
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Howard T, Greer-Short A, Satroplus T, Patel N, Nassal D, Mohler PJ, Hund TJ. CaMKII-dependent late Na + current increases electrical dispersion and arrhythmia in ischemia-reperfusion. Am J Physiol Heart Circ Physiol 2018; 315:H794-H801. [PMID: 29932771 DOI: 10.1152/ajpheart.00197.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The mechanisms underlying Ca2+/calmodulin-dependent protein kinase II (CaMKII)-induced arrhythmias in ischemia-reperfusion (I/R) are not fully understood. We tested the hypothesis that CaMKII increases late Na+ current ( INa,L) via phosphorylation of Nav1.5 at Ser571 during I/R, thereby increasing arrhythmia susceptibility. To test our hypothesis, we studied isolated, Langendorff-perfused hearts from wild-type (WT) mice and mice expressing Nav channel variants Nav1.5-Ser571E (S571E) and Nav1.5-Ser571A (S571A). WT hearts showed a significant increase in the levels of phosphorylated CaMKII and Nav1.5 at Ser571 [p-Nav1.5(S571)] after 15 min of global ischemia (just before the onset of reperfusion). Optical mapping experiments revealed an increase in action potential duration (APD) and APD dispersion without changes in conduction velocity during I/R in WT and S571E compared with S571A hearts. At the same time, WT and S571E hearts showed an increase in spontaneous arrhythmia events (e.g., premature ventricular contractions) and an increase in the inducibility of reentrant arrhythmias during reperfusion. Pretreatment of WT hearts with the Na+ channel blocker mexiletine (10 μM) normalized APD dispersion and reduced arrhythmia susceptibility during I/R. We conclude that CaMKII-dependent phosphorylation of Nav1.5 is a crucial driver for increased INa,L, arrhythmia triggers, and substrate during I/R. Selective targeting of this CaMKII-dependent pathway may have therapeutic potential for reducing arrhythmias in the setting of I/R. NEW & NOTEWORTHY Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylation of Nav1.5 at Ser571 leads to a prolongation of action potential duration (APD), increased APD dispersion, and increased arrhythmia susceptibility after ischemia-reperfusion in isolated mouse hearts. Genetic ablation of the CaMKII-dependent phosphorylation site Ser571 on Nav1.5 or low-dose mexiletine (to inhibit late Na+ current) reduced APD dispersion, arrhythmia triggers, and ventricular tachycardia inducibility.
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Affiliation(s)
- Taylor Howard
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio
| | - Amara Greer-Short
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio
| | - Tony Satroplus
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio
| | - Nehal Patel
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio
| | - Drew Nassal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio
| | - Peter J Mohler
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Internal Medicine, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center , Columbus, Ohio
| | - Thomas J Hund
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio.,Department of Internal Medicine, The Ohio State University Wexner Medical Center , Columbus, Ohio
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Zhou A, Shi G, Kang GJ, Xie A, Liu H, Jiang N, Liu M, Jeong EM, Dudley SC. RNA Binding Protein, HuR, Regulates SCN5A Expression Through Stabilizing MEF2C transcription factor mRNA. J Am Heart Assoc 2018; 7:JAHA.117.007802. [PMID: 29678826 PMCID: PMC6015277 DOI: 10.1161/jaha.117.007802] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Although transcription is the initial process of gene expression, posttranscriptional gene expression regulation has also played a critical role for fine-tuning gene expression in a fast, precise, and cost-effective manner. Although the regulation of sodium channel α-subunit (SCN5A) mRNA expression has been studied at both transcriptional and pre-mRNA splicing levels, the molecular mechanisms governing SCN5A mRNA expression are far from clear. METHODS AND RESULTS Herein, we show that, as evidenced by ribonucleoprotein immunoprecipitation assay, RNA binding protein Hu antigen R/ELAV like RNA binding protein 1 (HuR/ELAVL1) and myocyte enhancer factor-2C (MEF2C) transcription factor mRNA are associated. HuR positively regulated transcription factor MEF2C mRNA expression by protecting its mRNA from degradation. As demonstrated by both chromatin immunoprecipitation-quantitative polymerase chain reaction assay and an electrophoretic mobility shift assay, MEF2C enhanced SCN5A transcription by binding to a putative MEF2C binding site within SCN5A promoter region. Overexpression of HuR increased the expression of SCN5A mRNA, and this effect was attenuated by the presence of MEF2C small interfering RNA in cardiomyocytes. CONCLUSIONS In conclusion, our results suggested that HuR participates in a combined network at the DNA and RNA levels that regulates SCN5A mRNA expression. HuR upregulates MEF2C mRNA expression by protecting MEF2C mRNA from degradation, and consequently, the elevated MEF2C enhances SCN5A mRNA transcription.
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Affiliation(s)
- Anyu Zhou
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI
| | - Guangbin Shi
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI
| | - Gyeoung-Jin Kang
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - An Xie
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI.,Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Hong Liu
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI.,Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Ning Jiang
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI
| | - Man Liu
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI.,Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Euy-Myoung Jeong
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI
| | - Samuel C Dudley
- Department of Cardiology, Warren Alpert School of Medicine at Brown University, Providence, RI .,Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
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36
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Jensen B, Boukens BJ, Crossley DA, Conner J, Mohan RA, van Duijvenboden K, Postma AV, Gloschat CR, Elsey RM, Sedmera D, Efimov IR, Christoffels VM. Specialized impulse conduction pathway in the alligator heart. eLife 2018; 7:32120. [PMID: 29565246 PMCID: PMC5940360 DOI: 10.7554/elife.32120] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 03/20/2018] [Indexed: 01/30/2023] Open
Abstract
Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy. Mammals and birds are referred to as ‘warm-blooded’ animals, because they maintain a constant high body temperature. This requires a lot of energy, so their bodies need to be well supplied with blood at all times. The hearts of mammals and birds contain two important structures that help them do this. The first is a full wall of muscle – called the ventricular septum – that divides the heart into left and right sides. The second is an electrical circuit made of specialized muscle cells that ensures that the heart beats fast enough by sending rapid electrical signals to the rest of the heart muscle. The circuit contains one group of cells in the ventricular septum, called the bundle of His, and another group termed the Purkinje network. Reptiles, however, do not maintain high body temperatures and are instead often thought of as ‘cold-blooded’ animals. The hearts of reptiles do not need to pump blood around the body as quickly and have different structures from warm-blooded animals. For example, most reptile hearts do not have a fully developed ventricular septum. The only exceptions are crocodiles, alligators and their relatives (the ‘crocodilians’), which do. Jensen, Boukens et al. therefore wanted to determine if a crocodilian heart also contained a specialized electrical circuit like those of birds and mammals. Previous studies that attempted to answer this question using only anatomical and electrical methods had yielded ambiguous results. As such, Jensen, Boukens et al. combined these methods with genetic techniques for a more detailed study. First, the ventricular septum of American alligators, a species of crocodilian, was examined, and found to contain a narrow tissue structure that strongly resembled the bundle of His. Indeed, if this presumptive bundle of His was cut, the electrical circuit was broken. Additional genetic analysis of this structure confirmed that genes similar to those active in the mammalian bundle of His were also switched on in alligators. However, recordings of heart activity showed that heart rates and the spread of electrical signals were both slower in alligators than in warm-blooded animals. This suggests that, although alligators have evolved some specialized muscle cells (in the form of a bundle of His), their electrical circuit is still ‘incomplete’. The lack of a Purkinje network, for example, would explain why their heart rates remain slow like other reptiles’. Together these findings add to the current understanding of how the heart works in different animals with varying requirements for energy and blood flow. Also, since crocodiles and warm-blooded birds both evolved from ancient reptiles, detailed descriptions of their heart structures could shed more light on how warm-bloodedness first developed.
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Affiliation(s)
- Bjarke Jensen
- Department of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Bastiaan J Boukens
- Department of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Biomedical Engineering, George Washington University, Washington, DC, United States
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, United States
| | - Justin Conner
- Department of Biological Sciences, University of North Texas, Denton, United States
| | - Rajiv A Mohan
- Department of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Karel van Duijvenboden
- Department of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Alex V Postma
- Department of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Christopher R Gloschat
- Department of Biomedical Engineering, George Washington University, Washington, DC, United States
| | - Ruth M Elsey
- Rockefeller Wildlife Refuge, Louisiana Department of Wildlife and Fisheries, Grand Chenier, United States
| | - David Sedmera
- Institute of Anatomy, First Medical Faculty, Charles University, and Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC, United States
| | - Vincent M Christoffels
- Department of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Biophysical comparison of sodium currents in native cardiac myocytes and human induced pluripotent stem cell-derived cardiomyocytes. J Pharmacol Toxicol Methods 2017; 90:19-30. [PMID: 29128504 DOI: 10.1016/j.vascn.2017.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/22/2017] [Accepted: 11/02/2017] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used for safety pharmacology and to investigate genetic diseases affecting cardiac ion channels. It is unclear whether adult myocytes or hiPSC-CMs are the better platform for cardiac safety pharmacology. We examined the biophysical and molecular properties of INa in adult myocytes and hiPSC-CMs. METHODS hiPSC-CMs were plated at low density. Atrial and ventricular cells were obtained from dog hearts. Whole cell patch clamp was used to record INa. RESULTS Voltage clamp recordings showed a large INa in all three cell types but different densities. Small differences in steady-state inactivation and recovery from inactivation were noted in the three cell types. Application of lidocaine to the three cell types showed a similar pattern of block of INa under voltage clamp; however, lidocaine produced different effects on AP waveform under current clamp. AP clamp experiments showed that application of ventricular or atrial cell waveforms to the same hiPSC-CM elicited a large INa while application of a sinoatrial node waveform elicited no INa. Molecular analysis of Na+ channel subunits showed SCN5A and SCN1B-4B were expressed in adult cells and iPSC-CMs. However, iPSC-CMs express both fetal (exon 6A) and adult (exon 6) isoforms of SCN5A. DISCUSSION There are major differences in INa density and smaller differences in other biophysical properties of INa in adult atrial, ventricular, and hiPSC-CMs. The depolarized maximum diastolic potential coupled with the presence of phase 4 depolarization limits the contribution of INa in hiPSC-CM action potentials. Our results suggest that hiPSC-CMs may be useful for drug screening of Na+ channel inhibitors under voltage clamp but not current clamp.
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Osadchii OE. Role of abnormal repolarization in the mechanism of cardiac arrhythmia. Acta Physiol (Oxf) 2017; 220 Suppl 712:1-71. [PMID: 28707396 DOI: 10.1111/apha.12902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In cardiac patients, life-threatening tachyarrhythmia is often precipitated by abnormal changes in ventricular repolarization and refractoriness. Repolarization abnormalities typically evolve as a consequence of impaired function of outward K+ currents in cardiac myocytes, which may be caused by genetic defects or result from various acquired pathophysiological conditions, including electrical remodelling in cardiac disease, ion channel modulation by clinically used pharmacological agents, and systemic electrolyte disorders seen in heart failure, such as hypokalaemia. Cardiac electrical instability attributed to abnormal repolarization relies on the complex interplay between a provocative arrhythmic trigger and vulnerable arrhythmic substrate, with a central role played by the excessive prolongation of ventricular action potential duration, impaired intracellular Ca2+ handling, and slowed impulse conduction. This review outlines the electrical activity of ventricular myocytes in normal conditions and cardiac disease, describes classical electrophysiological mechanisms of cardiac arrhythmia, and provides an update on repolarization-related surrogates currently used to assess arrhythmic propensity, including spatial dispersion of repolarization, activation-repolarization coupling, electrical restitution, TRIaD (triangulation, reverse use dependence, instability, and dispersion), and the electromechanical window. This is followed by a discussion of the mechanisms that account for the dependence of arrhythmic vulnerability on the location of the ventricular pacing site. Finally, the review clarifies the electrophysiological basis for cardiac arrhythmia produced by hypokalaemia, and gives insight into the clinical importance and pathophysiology of drug-induced arrhythmia, with particular focus on class Ia (quinidine, procainamide) and Ic (flecainide) Na+ channel blockers, and class III antiarrhythmic agents that block the delayed rectifier K+ channel (dofetilide).
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Affiliation(s)
- O. E. Osadchii
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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Veerman CC, Podliesna S, Tadros R, Lodder EM, Mengarelli I, de Jonge B, Beekman L, Barc J, Wilders R, Wilde AAM, Boukens BJ, Coronel R, Verkerk AO, Remme CA, Bezzina CR. The Brugada Syndrome Susceptibility Gene HEY2 Modulates Cardiac Transmural Ion Channel Patterning and Electrical Heterogeneity. Circ Res 2017. [PMID: 28637782 DOI: 10.1161/circresaha.117.310959] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RATIONALE Genome-wide association studies previously identified an association of rs9388451 at chromosome 6q22.3 (near HEY2) with Brugada syndrome. The causal gene and underlying mechanism remain unresolved. OBJECTIVE We used an integrative approach entailing transcriptomic studies in human hearts and electrophysiological studies in Hey2+/- (Hey2 heterozygous knockout) mice to dissect the underpinnings of the 6q22.31 association with Brugada syndrome. METHODS AND RESULTS We queried expression quantitative trait locus data acquired in 190 human left ventricular samples from the genotype-tissue expression consortium for cis-expression quantitative trait locus effects of rs9388451, which revealed an association between Brugada syndrome risk allele dosage and HEY2 expression (β=+0.159; P=0.0036). In the same transcriptomic data, we conducted genome-wide coexpression analysis for HEY2, which uncovered KCNIP2, encoding the β-subunit of the channel underlying the transient outward current (Ito), as the transcript most robustly correlating with HEY2 expression (β=+1.47; P=2×10-34). Transcript abundance of Hey2 and the Ito subunits Kcnip2 and Kcnd2, assessed by quantitative reverse transcription-polymerase chain reaction, was higher in subepicardium versus subendocardium in both left and right ventricles, with lower levels in Hey2+/- mice compared with wild type. Surface ECG measurements showed less prominent J waves in Hey2+/- mice compared with wild-type. In wild-type mice, patch-clamp electrophysiological studies on cardiomyocytes from right ventricle demonstrated a shorter action potential duration and a lower Vmax in subepicardium compared with subendocardium cardiomyocytes, which was paralleled by a higher Ito and a lower sodium current (INa) density in subepicardium versus subendocardium. These transmural differences were diminished in Hey2+/- mice because of changes in subepicardial cardiomyocytes. CONCLUSIONS This study uncovers a role of HEY2 in the normal transmural electrophysiological gradient in the ventricle and provides compelling evidence that genetic variation at 6q22.31 (rs9388451) is associated with Brugada syndrome through a HEY2-dependent alteration of ion channel expression across the cardiac ventricular wall.
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Affiliation(s)
- Christiaan C Veerman
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Svitlana Podliesna
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Rafik Tadros
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Elisabeth M Lodder
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Isabella Mengarelli
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Berend de Jonge
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Leander Beekman
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Julien Barc
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Ronald Wilders
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Arthur A M Wilde
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Bastiaan J Boukens
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Ruben Coronel
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Arie O Verkerk
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Carol Ann Remme
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.)
| | - Connie R Bezzina
- From the Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands (C.C.V., S.P., R.T., E.M.L., I.M., L.B., A.A.M.W., R.C., A.O.V., C.A.R., C.R.B.); Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute, Canada (R.T.); Université de Montréal, Canada (R.T.); Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands (B.d.J., R.W., B.J.B., A.O.V.); INSERM, CNRS, Université de Nantes, L'institut du Thorax, Nantes, France (J.B.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia (A.A.M.W.); and Electrophysiology and Heart Modeling Institute LIRYC, Université de Bordeaux, France (R.C.).
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Abstract
The generation and propagation of the cardiac impulse is the central function of the cardiac conduction system (CCS). Impulse initiation occurs in nodal tissues that have high levels of automaticity, but slow conduction properties. Rapid impulse propagation is a feature of the ventricular conduction system, which is essential for synchronized contraction of the ventricular chambers. When functioning properly, the CCS produces ~2.4 billion heartbeats during a human lifetime and orchestrates the flow of cardiac impulses, designed to maximize cardiac output. Abnormal impulse initiation or propagation can result in brady- and tachy-arrhythmias, producing an array of symptoms, including syncope, heart failure or sudden cardiac death. Underlying the functional diversity of the CCS are gene regulatory networks that direct cell fate towards a nodal or a fast conduction gene program. In this review, we will discuss our current understanding of the transcriptional networks that dictate the components of the CCS, the growth factor-dependent signaling pathways that orchestrate some of these transcriptional hierarchies and the effect of aberrant transcription factor expression on mammalian conduction disease.
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Yang Z, Lu D, Zhang L, Hu J, Nie Z, Xie C, Qiu F, Cheng H, Yan Y. p.N1380del mutation in the pore-forming region of SCN5A gene is associated with cardiac conduction disturbance and ventricular tachycardia. Acta Biochim Biophys Sin (Shanghai) 2017; 49:270-276. [PMID: 28159958 DOI: 10.1093/abbs/gmx003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Indexed: 12/11/2022] Open
Abstract
Cardiac sodium channel plays a key role in the fast depolarization and maintenance of impulse conduction in cardiomyocytes. Mutations of SCN5A gene can lead to many types of arrhythmias. A 14-year-old boy with familial paternal history of sudden unexpected nocturnal death was admitted to hospital with recurrent syncope. A cardiac channelopathy was suspected and a pathogenic ion channel was searched for mutation identification. The proband manifested sinus node dysfunction, ventricular tachycardia, cardiac conduction disturbance involving atrioventricular node and His bundle. The proband and his mother received whole exome sequencing. A heterozygous in-frame deletion N1380del on exon 23 of SCN5A gene locating in a highly conserved pore residue in domain III (S5-S6) was revealed in the proband. The mutation was assessed in other family members by Sanger sequencing. The proband's living uncle and two sisters were asymptomatic mutation carriers with different degrees of cardiac conduction disturbance. Functional analysis was conducted using whole-cell patch clamping in HEK293T cells transfected with wild-type or mutant channels. The HEK293T cells transfected with plasmid pcDNA3.1-N1380del-SCN5A had no detectable sodium current. Overall, N1380del mutation of SCN5A gene leads to loss of function of sodium channel. N1380del is a pathogenetic mutation which can cause cardiac conduction defect and ventricular tachycardia.
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Affiliation(s)
- Zhen Yang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Danbo Lu
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Lei Zhang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jialu Hu
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zhenning Nie
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Chang Xie
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai 200031, China
| | - Fang Qiu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai 200031, China
| | - Hua Cheng
- WuXi NextCODE Genomics, Shanghai 200131, China
| | - Yan Yan
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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Transmural electrophysiological heterogeneity, the T-wave and ventricular arrhythmias. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:202-214. [DOI: 10.1016/j.pbiomolbio.2016.05.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/21/2016] [Accepted: 05/03/2016] [Indexed: 01/05/2023]
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Shekhar A, Lin X, Liu FY, Zhang J, Mo H, Bastarache L, Denny JC, Cox NJ, Delmar M, Roden DM, Fishman GI, Park DS. Transcription factor ETV1 is essential for rapid conduction in the heart. J Clin Invest 2016; 126:4444-4459. [PMID: 27775552 DOI: 10.1172/jci87968] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 09/15/2016] [Indexed: 01/12/2023] Open
Abstract
Rapid impulse propagation in the heart is a defining property of pectinated atrial myocardium (PAM) and the ventricular conduction system (VCS) and is essential for maintaining normal cardiac rhythm and optimal cardiac output. Conduction defects in these tissues produce a disproportionate burden of arrhythmic disease and are major predictors of mortality in heart failure patients. Despite the clinical importance, little is known about the gene regulatory network that dictates the fast conduction phenotype. Here, we have used signal transduction and transcriptional profiling screens to identify a genetic pathway that converges on the NRG1-responsive transcription factor ETV1 as a critical regulator of fast conduction physiology for PAM and VCS cardiomyocytes. Etv1 was highly expressed in murine PAM and VCS cardiomyocytes, where it regulates expression of Nkx2-5, Gja5, and Scn5a, key cardiac genes required for rapid conduction. Mice deficient in Etv1 exhibited marked cardiac conduction defects coupled with developmental abnormalities of the VCS. Loss of Etv1 resulted in a complete disruption of the normal sodium current heterogeneity that exists between atrial, VCS, and ventricular myocytes. Lastly, a phenome-wide association study identified a link between ETV1 and bundle branch block and heart block in humans. Together, these results identify ETV1 as a critical factor in determining fast conduction physiology in the heart.
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McKinnon D, Rosati B. Transmural gradients in ion channel and auxiliary subunit expression. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:165-186. [PMID: 27702655 DOI: 10.1016/j.pbiomolbio.2016.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/30/2016] [Indexed: 12/11/2022]
Abstract
Evolution has acted to shape the action potential in different regions of the heart in order to produce a maximally stable and efficient pump. This has been achieved by creating regional differences in ion channel expression levels within the heart as well as differences between equivalent cardiac tissues in different species. These region- and species-dependent differences in channel expression are established by regulatory evolution, evolution of the regulatory mechanisms that control channel expression levels. Ion channel auxiliary subunits are obvious targets for regulatory evolution, in order to change channel expression levels and/or modify channel function. This review focuses on the transmural gradients of ion channel expression in the heart and the role that regulation of auxiliary subunit expression plays in generating and shaping these gradients.
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Affiliation(s)
- David McKinnon
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Barbara Rosati
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.
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Ravindran K, Powell KL, Todaro M, O'Brien TJ. The pathophysiology of cardiac dysfunction in epilepsy. Epilepsy Res 2016; 127:19-29. [PMID: 27544485 DOI: 10.1016/j.eplepsyres.2016.08.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 08/07/2016] [Accepted: 08/10/2016] [Indexed: 11/15/2022]
Abstract
Alterations in cardiac electrophysiology are an established consequence of long-standing drug resistant epilepsy. Patients with chronic epilepsy display abnormalities in both sinoatrial node pacemaker current as well as ventricular repolarizing current that places them at a greater risk of developing life-threatening cardiac arrhythmias. The development of cardiac arrhythmias secondary to drug resistant epilepsy is believed to be a key mechanism underlying the phenomenon of Sudden Unexpected Death in EPilepsy (SUDEP). Though an increasing amount of studies examining both animal models and human patients have provided evidence that chronic epilepsy can detrimentally affect cardiac function, the underlying pathophysiology remains unclear. Recent work has shown the expression of several key cardiac ion channels to be altered in animal models of genetic and acquired epilepsies. This has led to the currently held paradigm that cardiac ion channel expression may be secondarily altered as a consequence of seizure activity-resulting in electrophysiological cardiac dysfunction. Furthermore, cortical autonomic dysfunction - resulting from seizure activity-has also been suggested to play a role, whereby seizure activity may indirectly influence cardiac function via altering centrally-mediated autonomic output to the heart. In this review, we discuss various cardiac dysrhythmias associated with seizure events-including tachycardia, bradycardia and QT prolongation, both ictally and inter-ictally, as well as the role of the autonomic nervous system. We further discuss key ion channels expressed in both the heart and the brain that have been shown to be altered in epilepsy and may be responsible for the development of cardiac dysrhythmias secondary to chronic epilepsy.
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Affiliation(s)
- Krishnan Ravindran
- Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, Australia.
| | - Kim L Powell
- Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Marian Todaro
- Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Terence J O'Brien
- Department of Medicine, The University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, Australia.
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van Weerd JH, Christoffels VM. The formation and function of the cardiac conduction system. Development 2016; 143:197-210. [PMID: 26786210 DOI: 10.1242/dev.124883] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The cardiac conduction system (CCS) consists of distinctive components that initiate and conduct the electrical impulse required for the coordinated contraction of the cardiac chambers. CCS development involves complex regulatory networks that act in stage-, tissue- and dose-dependent manners, and recent findings indicate that the activity of these networks is sensitive to common genetic variants associated with cardiac arrhythmias. Here, we review how these findings have provided novel insights into the regulatory mechanisms and transcriptional networks underlying CCS formation and function.
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Affiliation(s)
- Jan Hendrik van Weerd
- Department of Anatomy, Embryology & Physiology, Academic Medical Center, Amsterdam 1105 AZ, The Netherlands
| | - Vincent M Christoffels
- Department of Anatomy, Embryology & Physiology, Academic Medical Center, Amsterdam 1105 AZ, The Netherlands
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Tse G, Tse V, Yeo JM, Sun B. Atrial Anti-Arrhythmic Effects of Heptanol in Langendorff-Perfused Mouse Hearts. PLoS One 2016; 11:e0148858. [PMID: 26872148 PMCID: PMC4752503 DOI: 10.1371/journal.pone.0148858] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 01/24/2016] [Indexed: 12/24/2022] Open
Abstract
Acute effects of heptanol (0.1 to 2 mM) on atrial electrophysiology were explored in Langendorff-perfused mouse hearts. Left atrial bipolar electrogram or monophasic action potential recordings were obtained during right atrial stimulation. Regular pacing at 8 Hz elicited atrial activity in 11 out of 11 hearts without inducing atrial arrhythmias. Programmed electrical stimulation using a S1S2 protocol provoked atrial tachy-arrhythmias in 9 of 17 hearts. In the initially arrhythmic group, 2 mM heptanol exerted anti-arrhythmic effects (Fisher’s exact test, P < 0.05) and increased atrial effective refractory period (ERP) from 26.0 ± 1.9 to 57.1 ± 2.5 ms (ANOVA, P < 0.001) despite increasing activation latency from 18.7 ± 1.1 to 28.9 ± 2.1 ms (P < 0.001) and leaving action potential duration at 90% repolarization (APD90) unaltered (25.6 ± 1.2 vs. 27.2 ± 1.2 ms; P > 0.05), which led to increases in ERP/latency ratio from 1.4 ± 0.1 to 2.1 ± 0.2 and ERP/APD90 ratio from 1.0 ± 0.1 to 2.1 ± 0.2 (P < 0.001). In contrast, in the initially non-arrhythmic group, heptanol did not alter arrhythmogenicity, increased AERP from 47.3 ± 5.3 to 54.5 ± 3.1 ms (P < 0.05) and activation latency from 23.7 ± 2.2 to 31.3 ± 2.5 ms and did not alter APD90 (24.1 ± 1.2 vs. 25.0 ± 2.3 ms; P > 0.05), leaving both AERP/latency ratio (2.1 ± 0.3 vs. 1.9 ± 0.2; P > 0.05) and ERP/APD90 ratio (2.0 ± 0.2 vs. 2.1 ± 0.1; P > 0.05) unaltered. Lower heptanol concentrations (0.1, 0.5 and 1 mM) did not alter arrhythmogenicity or the above parameters. The present findings contrast with known ventricular pro-arrhythmic effects of heptanol associated with decreased ERP/latency ratio, despite increased ERP/APD ratio observed in both the atria and ventricles.
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Affiliation(s)
- Gary Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong S.A.R., China
| | - Vivian Tse
- Department of Physiology, McGill University, Montreal, Canada
| | - Jie Ming Yeo
- Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Bing Sun
- Department of Cardiology, Tongji University Affiliated Tongji Hospital, Shanghai, China
- * E-mail:
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Baruscotti M, Bianco E, Bucchi A, DiFrancesco D. Current understanding of the pathophysiological mechanisms responsible for inappropriate sinus tachycardia: role of the If "funny" current. J Interv Card Electrophysiol 2016; 46:19-28. [PMID: 26781742 DOI: 10.1007/s10840-015-0097-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 12/28/2015] [Indexed: 01/01/2023]
Abstract
BACKGROUND Together with the afferent branches of the autonomic nervous system, the sinoatrial node (SAN) forms a functional unit whose function is to fire rhythmic action potentials at a rate optimal for coping with the metabolic needs of the body. Dysfunctional behavior of this complex unit may thus result in SAN rhythm disorders. Among these disorders, there is the inappropriate sinus tachycardia (IST) which occurs when an unjustified fast SAN rate is present. METHODS We here present a critical review of the role of pacemaker f/HCN channels in cardiac rhythm generation and modulation and their involvement in IST. RESULTS Recent evidence demonstrates that a familial form of IST is associated with a gain-of-function mutation in the HCN4 pacemaker channel (R524Q) which confers an increased sensitivity to the second messenger cAMP, a key mediator in sympathetic modulation. CONCLUSIONS This finding is consistent with the general view that hypersympathetic tone is one of the causes of IST and introduces the novel concept of defective funny channel-dependent tachyarrhythmias.
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Affiliation(s)
- Mirko Baruscotti
- Department of Biosciences, Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata, University of Milano, via Celoria 26, 20133, Milano, Italy.
| | - Elisabetta Bianco
- Cardiovascular Department, "Ospedali Riuniti di Trieste", University Hospital, Trieste, Italy
| | - Annalisa Bucchi
- Department of Biosciences, Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata, University of Milano, via Celoria 26, 20133, Milano, Italy
| | - Dario DiFrancesco
- Department of Biosciences, Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata, University of Milano, via Celoria 26, 20133, Milano, Italy.
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Liu J, Laksman Z, Backx PH. The electrophysiological development of cardiomyocytes. Adv Drug Deliv Rev 2016; 96:253-73. [PMID: 26788696 DOI: 10.1016/j.addr.2015.12.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/23/2015] [Accepted: 12/31/2015] [Indexed: 02/07/2023]
Abstract
The generation of human cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) has become an important resource for modeling human cardiac disease and for drug screening, and also holds significant potential for cardiac regeneration. Many challenges remain to be overcome however, before innovation in this field can translate into a change in the morbidity and mortality associated with heart disease. Of particular importance for the future application of this technology is an improved understanding of the electrophysiologic characteristics of CMs, so that better protocols can be developed and optimized for generating hPSC-CMs. Many different cell culture protocols are currently utilized to generate CMs from hPSCs and all appear to yield relatively “developmentally” immature CMs with highly heterogeneous electrical properties. These hPSC-CMs are characterized by spontaneous beating at highly variable rates with a broad range of depolarization-repolarization patterns, suggestive of mixed populations containing atrial, ventricular and nodal cells. Many recent studies have attempted to introduce approaches to promote maturation and to create cells with specific functional properties. In this review, we summarize the studies in which the electrical properties of CMs derived from stem cells have been examined. In order to place this information in a useful context, we also review the electrical properties of CMs as they transition from the developing embryo to the adult human heart. The signal pathways involved in the regulation of ion channel expression during development are also briefly considered.
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Weisbrod D, Khun SH, Bueno H, Peretz A, Attali B. Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels. Acta Pharmacol Sin 2016; 37:82-97. [PMID: 26725737 PMCID: PMC4722971 DOI: 10.1038/aps.2015.135] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/25/2015] [Indexed: 12/25/2022] Open
Abstract
The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca(2+)-activated K(+) channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity.
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Affiliation(s)
- David Weisbrod
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shiraz Haron Khun
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hanna Bueno
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Asher Peretz
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Bernard Attali
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
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