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Angom RS, Joshi A, Patowary A, Sivadas A, Ramasamy S, K. V. S, Kaushik K, Sabharwal A, Lalwani MK, K. S, Singh N, Scaria V, Sivasubbu S. Forward genetic screen using a gene-breaking trap approach identifies a novel role of grin2bb-associated RNA transcript ( grin2bbART) in zebrafish heart function. Front Cell Dev Biol 2024; 12:1339292. [PMID: 38533084 PMCID: PMC10964321 DOI: 10.3389/fcell.2024.1339292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/23/2024] [Indexed: 03/28/2024] Open
Abstract
LncRNA-based control affects cardiac pathophysiologies like myocardial infarction, coronary artery disease, hypertrophy, and myotonic muscular dystrophy. This study used a gene-break transposon (GBT) to screen zebrafish (Danio rerio) for insertional mutagenesis. We identified three insertional mutants where the GBT captured a cardiac gene. One of the adult viable GBT mutants had bradycardia (heart arrhythmia) and enlarged cardiac chambers or hypertrophy; we named it "bigheart." Bigheart mutant insertion maps to grin2bb or N-methyl D-aspartate receptor (NMDAR2B) gene intron 2 in reverse orientation. Rapid amplification of adjacent cDNA ends analysis suggested a new insertion site transcript in the intron 2 of grin2bb. Analysis of the RNA sequencing of wild-type zebrafish heart chambers revealed a possible new transcript at the insertion site. As this putative lncRNA transcript satisfies the canonical signatures, we called this transcript grin2bb associated RNA transcript (grin2bbART). Using in situ hybridization, we confirmed localized grin2bbART expression in the heart, central nervous system, and muscles in the developing embryos and wild-type adult zebrafish atrium and bulbus arteriosus. The bigheart mutant had reduced Grin2bbART expression. We showed that bigheart gene trap insertion excision reversed cardiac-specific arrhythmia and atrial hypertrophy and restored grin2bbART expression. Morpholino-mediated antisense downregulation of grin2bbART in wild-type zebrafish embryos mimicked bigheart mutants; this suggests grin2bbART is linked to bigheart. Cardiovascular tissues use Grin2bb as a calcium-permeable ion channel. Calcium imaging experiments performed on bigheart mutants indicated calcium mishandling in the heart. The bigheart cardiac transcriptome showed differential expression of calcium homeostasis, cardiac remodeling, and contraction genes. Western blot analysis highlighted Camk2d1 and Hdac1 overexpression. We propose that altered calcium activity due to disruption of grin2bbART, a putative lncRNA in bigheart, altered the Camk2d-Hdac pathway, causing heart arrhythmia and hypertrophy in zebrafish.
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Affiliation(s)
- Ramcharan Singh Angom
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Jacksonville, FL, United States
| | - Adita Joshi
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Ashok Patowary
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Ambily Sivadas
- GN Ramachandran Knowledge Center for Genome Informatics, Council of Scientific and Industrial Research, Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Soundhar Ramasamy
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Shamsudheen K. V.
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
- GN Ramachandran Knowledge Center for Genome Informatics, Council of Scientific and Industrial Research, Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Kriti Kaushik
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Ankit Sabharwal
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Mukesh Kumar Lalwani
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Subburaj K.
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Naresh Singh
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Vinod Scaria
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
- GN Ramachandran Knowledge Center for Genome Informatics, Council of Scientific and Industrial Research, Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Sridhar Sivasubbu
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
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Salgado-Almario J, Molina Y, Vicente M, Martínez-Sielva A, Rodríguez-García R, Vincent P, Domingo B, Llopis J. ERG potassium channels and T-type calcium channels contribute to the pacemaker and atrioventricular conduction in zebrafish larvae. Acta Physiol (Oxf) 2024; 240:e14075. [PMID: 38071417 DOI: 10.1111/apha.14075] [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: 08/12/2023] [Revised: 11/14/2023] [Accepted: 11/22/2023] [Indexed: 02/01/2024]
Abstract
AIM Bradyarrhythmias result from inhibition of automaticity, prolonged repolarization, or slow conduction in the heart. The ERG channels mediate the repolarizing current IKr in the cardiac action potential, whereas T-type calcium channels (TTCC) are involved in the sinoatrial pacemaker and atrioventricular conduction in mammals. Zebrafish have become a valuable research model for human cardiac electrophysiology and disease. Here, we investigate the contribution of ERG channels and TTCCs to the pacemaker and atrioventricular conduction in zebrafish larvae and determine the mechanisms causing atrioventricular block. METHODS Zebrafish larvae expressing ratiometric fluorescent Ca2+ biosensors in the heart were used to measure Ca2+ levels and rhythm in beating hearts in vivo, concurrently with contraction and hemodynamics. The atrioventricular delay (the time between the start of atrial and ventricular Ca2+ transients) was used to measure impulse conduction velocity and distinguished between slow conduction and prolonged refractoriness as the cause of the conduction block. RESULTS ERG blockers caused bradycardia and atrioventricular block by prolonging the refractory period in the atrioventricular canal and in working ventricular myocytes. In contrast, inhibition of TTCCs caused bradycardia and second-degree block (Mobitz type I) by slowing atrioventricular conduction. TTCC block did not affect ventricular contractility, despite being highly expressed in cardiomyocytes. Concomitant measurement of Ca2+ levels and ventricular size showed mechano-mechanical coupling: increased preload resulted in a stronger heart contraction in vivo. CONCLUSION ERG channels and TTCCs influence the heart rate and atrioventricular conduction in zebrafish larvae. The zebrafish lines expressing Ca2+ biosensors in the heart allow us to investigate physiological feedback mechanisms and complex arrhythmias.
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Affiliation(s)
- Jussep Salgado-Almario
- Physiology and Cell Dynamics, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Yillcer Molina
- Physiology and Cell Dynamics, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Manuel Vicente
- Physiology and Cell Dynamics, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Antonio Martínez-Sielva
- Physiology and Cell Dynamics, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Raúl Rodríguez-García
- Physiology and Cell Dynamics, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Pierre Vincent
- IGF, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Beatriz Domingo
- Physiology and Cell Dynamics, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Juan Llopis
- Physiology and Cell Dynamics, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
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Baillie JS, Gendernalik A, Garrity DM, Bark D, Quinn TA. The in vivo study of cardiac mechano-electric and mechano-mechanical coupling during heart development in zebrafish. Front Physiol 2023; 14:1086050. [PMID: 37007999 PMCID: PMC10060984 DOI: 10.3389/fphys.2023.1086050] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
In the adult heart, acute adaptation of electrical and mechanical activity to changes in mechanical load occurs via feedback processes known as “mechano-electric coupling” and “mechano-mechanical coupling.” Whether this occurs during cardiac development is ill-defined, as acutely altering the heart’s mechanical load while measuring functional responses in traditional experimental models is difficult, as embryogenesis occurs in utero, making the heart inaccessible. These limitations can be overcome with zebrafish, as larvae develop in a dish and are nearly transparent, allowing for in vivo manipulation and measurement of cardiac structure and function. Here we present a novel approach for the in vivo study of mechano-electric and mechano-mechanical coupling in the developing zebrafish heart. This innovative methodology involves acute in vivo atrial dilation (i.e., increased atrial preload) in larval zebrafish by injection of a controlled volume into the venous circulation immediately upstream of the heart, combined with optical measurement of the acute electrical (change in heart rate) and mechanical (change in stroke area) response. In proof-of-concept experiments, we applied our new method to 48 h post-fertilisation zebrafish, which revealed differences between the electrical and mechanical response to atrial dilation. In response to an acute increase in atrial preload there is a large increase in atrial stroke area but no change in heart rate, demonstrating that in contrast to the fully developed heart, during early cardiac development mechano-mechanical coupling alone drives the adaptive increase in atrial output. Overall, in this methodological paper we present our new experimental approach for the study of mechano-electric and mechano-mechanical coupling during cardiac development and demonstrate its potential for understanding the essential adaptation of heart function to acute changes in mechanical load.
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Affiliation(s)
| | - Alex Gendernalik
- Biomedical Engineering, Colorado State University, Fort Collins, CO, United States
| | | | - David Bark
- Biomedical Engineering, Colorado State University, Fort Collins, CO, United States
- Mechanical Engineering, Colorado State University, Fort Collins, CO, United States
- Department of Pediatrics, Washington University in St. Louis, St. Louis, MO, United States
| | - T. Alexander Quinn
- Physiology & Biophysics, Dalhousie University, Halifax, NS, Canada
- Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
- *Correspondence: T. Alexander Quinn,
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Welzel G, Schuster S. Electric catfish hearts are not intrinsically immune to electric shocks. J Exp Biol 2022; 225:276258. [PMID: 35946177 DOI: 10.1242/jeb.244307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 07/19/2022] [Indexed: 10/15/2022]
Abstract
High voltage electric shocks cause life threatening cardiac injuries such as sudden cardiac standstill or severe myocardial injury. Here, we analysed the physiology of the heart of the strongly electric catfish (Malapterurus beninensis) that stuns prey with high-voltage shocks but is immune to its own, as well as external, high-voltage shocks. Neither a detailed analysis of the electrocardiogram nor the structure of the heart indicated a specialized cardiac conduction system. Using a suitable perfusion system, we discovered that, despite its immunity in vivo, the explanted heart of electric catfish can readily be activated by external electrical currents and is equally sensitive to electric shock-induced arrhythmias as similar-sized goldfish hearts. The surprise thus is that the electric catfish has a vulnerable heart that requires to be protected by highly efficient but presently unknown means.
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Affiliation(s)
- Georg Welzel
- Department of Animal Physiology, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - Stefan Schuster
- Department of Animal Physiology, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
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Gauvrit S, Bossaer J, Lee J, Collins MM. Modeling Human Cardiac Arrhythmias: Insights from Zebrafish. J Cardiovasc Dev Dis 2022; 9:jcdd9010013. [PMID: 35050223 PMCID: PMC8779270 DOI: 10.3390/jcdd9010013] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/23/2021] [Accepted: 12/25/2021] [Indexed: 12/13/2022] Open
Abstract
Cardiac arrhythmia, or irregular heart rhythm, is associated with morbidity and mortality and is described as one of the most important future public health challenges. Therefore, developing new models of cardiac arrhythmia is critical for understanding disease mechanisms, determining genetic underpinnings, and developing new therapeutic strategies. In the last few decades, the zebrafish has emerged as an attractive model to reproduce in vivo human cardiac pathologies, including arrhythmias. Here, we highlight the contribution of zebrafish to the field and discuss the available cardiac arrhythmia models. Further, we outline techniques to assess potential heart rhythm defects in larval and adult zebrafish. As genetic tools in zebrafish continue to bloom, this model will be crucial for functional genomics studies and to develop personalized anti-arrhythmic therapies.
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Baillie JS, Stoyek MR, Quinn TA. Seeing the Light: The Use of Zebrafish for Optogenetic Studies of the Heart. Front Physiol 2021; 12:748570. [PMID: 35002753 PMCID: PMC8733579 DOI: 10.3389/fphys.2021.748570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
Optogenetics, involving the optical measurement and manipulation of cellular activity with genetically encoded light-sensitive proteins ("reporters" and "actuators"), is a powerful experimental technique for probing (patho-)physiological function. Originally developed as a tool for neuroscience, it has now been utilized in cardiac research for over a decade, providing novel insight into the electrophysiology of the healthy and diseased heart. Among the pioneering cardiac applications of optogenetic actuators were studies in zebrafish, which first demonstrated their use for precise spatiotemporal control of cardiac activity. Zebrafish were also adopted early as an experimental model for the use of optogenetic reporters, including genetically encoded voltage- and calcium-sensitive indicators. Beyond optogenetic studies, zebrafish are becoming an increasingly important tool for cardiac research, as they combine many of the advantages of integrative and reduced experimental models. The zebrafish has striking genetic and functional cardiac similarities to that of mammals, its genome is fully sequenced and can be modified using standard techniques, it has been used to recapitulate a variety of cardiac diseases, and it allows for high-throughput investigations. For optogenetic studies, zebrafish provide additional advantages, as the whole zebrafish heart can be visualized and interrogated in vivo in the transparent, externally developing embryo, and the relatively small adult heart allows for in situ cell-specific observation and control not possible in mammals. With the advent of increasingly sophisticated fluorescence imaging approaches and methods for spatially-resolved light stimulation in the heart, the zebrafish represents an experimental model with unrealized potential for cardiac optogenetic studies. In this review we summarize the use of zebrafish for optogenetic investigations in the heart, highlighting their specific advantages and limitations, and their potential for future cardiac research.
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Affiliation(s)
- Jonathan S. Baillie
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Matthew R. Stoyek
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - T. Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
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Vicente M, Salgado-Almario J, Collins MM, Martínez-Sielva A, Minoshima M, Kikuchi K, Domingo B, Llopis J. Cardioluminescence in Transgenic Zebrafish Larvae: A Calcium Imaging Tool to Study Drug Effects and Pathological Modeling. Biomedicines 2021; 9:biomedicines9101294. [PMID: 34680411 PMCID: PMC8533351 DOI: 10.3390/biomedicines9101294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/07/2021] [Accepted: 09/20/2021] [Indexed: 01/12/2023] Open
Abstract
Zebrafish embryos and larvae have emerged as an excellent model in cardiovascular research and are amenable to live imaging with genetically encoded biosensors to study cardiac cell behaviours, including calcium dynamics. To monitor calcium ion levels in three to five days post-fertilization larvae, we have used bioluminescence. We generated a transgenic line expressing GFP-aequorin in the heart, Tg(myl7:GA), and optimized a reconstitution protocol to boost aequorin luminescence. The analogue diacetylh-coelenterazine enhanced light output and signal-to-noise ratio. With this cardioluminescence model, we imaged the time-averaged calcium levels and beat-to-beat calcium oscillations continuously for hours. As a proof-of-concept of the transgenic line, changes in ventricular calcium levels were observed by Bay K8644, an L-type calcium channel activator and with the blocker nifedipine. The β-adrenergic blocker propranolol decreased calcium levels, heart rate, stroke volume, and cardiac output, suggesting that larvae have a basal adrenergic tone. Zebrafish larvae treated with terfenadine for 24 h have been proposed as a model of heart failure. Tg(myl7:GA) larvae treated with terfenadine showed bradycardia, 2:1 atrioventricular block, decreased time-averaged ventricular calcium levels but increased calcium transient amplitude, and reduced cardiac output. As alterations of calcium signalling are involved in the pathogenesis of heart failure and arrhythmia, the GFP-aequorin transgenic line provides a powerful platform for understanding calcium dynamics.
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Affiliation(s)
- Manuel Vicente
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain; (M.V.); (J.S.-A.); (A.M.-S.)
| | - Jussep Salgado-Almario
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain; (M.V.); (J.S.-A.); (A.M.-S.)
| | - Michelle M. Collins
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
| | - Antonio Martínez-Sielva
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain; (M.V.); (J.S.-A.); (A.M.-S.)
| | - Masafumi Minoshima
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan; (M.M.); (K.K.)
| | - Kazuya Kikuchi
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan; (M.M.); (K.K.)
- WPI-Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Beatriz Domingo
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain; (M.V.); (J.S.-A.); (A.M.-S.)
- Correspondence: (B.D.); (J.L.); Tel.: +34-967-599-315 (J.L.); +34-967-599-200 (ext. 2686) (B.D.)
| | - Juan Llopis
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain; (M.V.); (J.S.-A.); (A.M.-S.)
- Correspondence: (B.D.); (J.L.); Tel.: +34-967-599-315 (J.L.); +34-967-599-200 (ext. 2686) (B.D.)
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The zebrafish grime mutant uncovers an evolutionarily conserved role for Tmem161b in the control of cardiac rhythm. Proc Natl Acad Sci U S A 2021; 118:2018220118. [PMID: 33597309 DOI: 10.1073/pnas.2018220118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The establishment of cardiac function in the developing embryo is essential to ensure blood flow and, therefore, growth and survival of the animal. The molecular mechanisms controlling normal cardiac rhythm remain to be fully elucidated. From a forward genetic screen, we identified a unique mutant, grime, that displayed a specific cardiac arrhythmia phenotype. We show that loss-of-function mutations in tmem161b are responsible for the phenotype, identifying Tmem161b as a regulator of cardiac rhythm in zebrafish. To examine the evolutionary conservation of this function, we generated knockout mice for Tmem161b. Tmem161b knockout mice are neonatal lethal and cardiomyocytes exhibit arrhythmic calcium oscillations. Mechanistically, we find that Tmem161b is expressed at the cell membrane of excitable cells and live imaging shows it is required for action potential repolarization in the developing heart. Electrophysiology on isolated cardiomyocytes demonstrates that Tmem161b is essential to inhibit Ca2+ and K+ currents in cardiomyocytes. Importantly, Tmem161b haploinsufficiency leads to cardiac rhythm phenotypes, implicating it as a candidate gene in heritable cardiac arrhythmia. Overall, these data describe Tmem161b as a highly conserved regulator of cardiac rhythm that functions to modulate ion channel activity in zebrafish and mice.
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Simpson KE, Venkateshappa R, Pang ZK, Faizi S, Tibbits GF, Claydon TW. Utility of Zebrafish Models of Acquired and Inherited Long QT Syndrome. Front Physiol 2021; 11:624129. [PMID: 33519527 PMCID: PMC7844309 DOI: 10.3389/fphys.2020.624129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/21/2020] [Indexed: 01/12/2023] Open
Abstract
Long-QT Syndrome (LQTS) is a cardiac electrical disorder, distinguished by irregular heart rates and sudden death. Accounting for ∼40% of cases, LQTS Type 2 (LQTS2), is caused by defects in the Kv11.1 (hERG) potassium channel that is critical for cardiac repolarization. Drug block of hERG channels or dysfunctional channel variants can result in acquired or inherited LQTS2, respectively, which are typified by delayed repolarization and predisposition to lethal arrhythmia. As such, there is significant interest in clear identification of drugs and channel variants that produce clinically meaningful perturbation of hERG channel function. While toxicological screening of hERG channels, and phenotypic assessment of inherited channel variants in heterologous systems is now commonplace, affordable, efficient, and insightful whole organ models for acquired and inherited LQTS2 are lacking. Recent work has shown that zebrafish provide a viable in vivo or whole organ model of cardiac electrophysiology. Characterization of cardiac ion currents and toxicological screening work in intact embryos, as well as adult whole hearts, has demonstrated the utility of the zebrafish model to contribute to the development of therapeutics that lack hERG-blocking off-target effects. Moreover, forward and reverse genetic approaches show zebrafish as a tractable model in which LQTS2 can be studied. With the development of new tools and technologies, zebrafish lines carrying precise channel variants associated with LQTS2 have recently begun to be generated and explored. In this review, we discuss the present knowledge and questions raised related to the use of zebrafish as models of acquired and inherited LQTS2. We focus discussion, in particular, on developments in precise gene-editing approaches in zebrafish to create whole heart inherited LQTS2 models and evidence that zebrafish hearts can be used to study arrhythmogenicity and to identify potential anti-arrhythmic compounds.
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Affiliation(s)
- Kyle E. Simpson
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Ravichandra Venkateshappa
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Zhao Kai Pang
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Shoaib Faizi
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Glen F. Tibbits
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- Department of Cardiovascular Science, British Columbia Children’s Hospital, Vancouver, BC, Canada
| | - Tom W. Claydon
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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Sieliwonczyk E, Matchkov VV, Vandendriessche B, Alaerts M, Bakkers J, Loeys B, Schepers D. Inherited Ventricular Arrhythmia in Zebrafish: Genetic Models and Phenotyping Tools. Rev Physiol Biochem Pharmacol 2021; 184:33-68. [PMID: 34533615 DOI: 10.1007/112_2021_65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In the last years, the field of inheritable ventricular arrhythmia disease modelling has changed significantly with a push towards the use of novel cellular cardiomyocyte based models. However, there is a growing need for new in vivo models to study the disease pathology at the tissue and organ level. Zebrafish provide an excellent opportunity for in vivo modelling of inheritable ventricular arrhythmia syndromes due to the remarkable similarity between their cardiac electrophysiology and that of humans. Additionally, many state-of-the-art methods in gene editing and electrophysiological phenotyping are available for zebrafish research. In this review, we give a comprehensive overview of the published zebrafish genetic models for primary electrical disorders and arrhythmogenic cardiomyopathy. We summarise and discuss the strengths and weaknesses of the different technical approaches for the generation of genetically modified zebrafish disease models, as well as the electrophysiological approaches in zebrafish phenotyping. By providing this detailed overview, we aim to draw attention to the potential of the zebrafish model for studying arrhythmia syndromes at the organ level and as a platform for personalised medicine and drug testing.
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Affiliation(s)
- Ewa Sieliwonczyk
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium.
| | - Vladimir V Matchkov
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
| | - Bert Vandendriessche
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Maaike Alaerts
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Jeroen Bakkers
- Hubrecht Institute for Developmental and Stem Cell Biology, Utrecht, The Netherlands
| | - Bart Loeys
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Dorien Schepers
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium.,Laboratory for Molecular, Cellular and Network Excitability, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
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Wei J, Yao J, Belke D, Guo W, Zhong X, Sun B, Wang R, Paul Estillore J, Vallmitjana A, Benitez R, Hove-Madsen L, Alvarez-Lacalle E, Echebarria B, Chen SRW. Ca 2+-CaM Dependent Inactivation of RyR2 Underlies Ca 2+ Alternans in Intact Heart. Circ Res 2020; 128:e63-e83. [PMID: 33375811 DOI: 10.1161/circresaha.120.318429] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
RATIONALE Ca2+ alternans plays an essential role in cardiac alternans that can lead to ventricular fibrillation, but the mechanism underlying Ca2+ alternans remains undefined. Increasing evidence suggests that Ca2+ alternans results from alternations in the inactivation of cardiac RyR2 (ryanodine receptor 2). However, what inactivates RyR2 and how RyR2 inactivation leads to Ca2+ alternans are unknown. OBJECTIVE To determine the role of CaM (calmodulin) on Ca2+ alternans in intact working mouse hearts. METHODS AND RESULTS We used an in vivo local gene delivery approach to alter CaM function by directly injecting adenoviruses expressing CaM-wild type, a loss-of-function CaM mutation, CaM (1-4), and a gain-of-function mutation, CaM-M37Q, into the anterior wall of the left ventricle of RyR2 wild type or mutant mouse hearts. We monitored Ca2+ transients in ventricular myocytes near the adenovirus-injection sites in Langendorff-perfused intact working hearts using confocal Ca2+ imaging. We found that CaM-wild type and CaM-M37Q promoted Ca2+ alternans and prolonged Ca2+ transient recovery in intact RyR2 wild type and mutant hearts, whereas CaM (1-4) exerted opposite effects. Altered CaM function also affected the recovery from inactivation of the L-type Ca2+ current but had no significant impact on sarcoplasmic reticulum Ca2+ content. Furthermore, we developed a novel numerical myocyte model of Ca2+ alternans that incorporates Ca2+-CaM-dependent regulation of RyR2 and the L-type Ca2+ channel. Remarkably, the new model recapitulates the impact on Ca2+ alternans of altered CaM and RyR2 functions under 9 different experimental conditions. Our simulations reveal that diastolic cytosolic Ca2+ elevation as a result of rapid pacing triggers Ca2+-CaM dependent inactivation of RyR2. The resultant RyR2 inactivation diminishes sarcoplasmic reticulum Ca2+ release, which, in turn, reduces diastolic cytosolic Ca2+, leading to alternations in diastolic cytosolic Ca2+, RyR2 inactivation, and sarcoplasmic reticulum Ca2+ release (ie, Ca2+ alternans). CONCLUSIONS Our results demonstrate that inactivation of RyR2 by Ca2+-CaM is a major determinant of Ca2+ alternans, making Ca2+-CaM dependent regulation of RyR2 an important therapeutic target for cardiac alternans.
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Affiliation(s)
- Jinhong Wei
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Jinjing Yao
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Darrell Belke
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Wenting Guo
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Xiaowei Zhong
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Bo Sun
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Ruiwu Wang
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - John Paul Estillore
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Alexander Vallmitjana
- Department of Automatic Control, Universitat Politècnica de Catalunya, Barcelona, Spain (A.V., R.B.)
| | - Raul Benitez
- Department of Automatic Control, Universitat Politècnica de Catalunya, Barcelona, Spain (A.V., R.B.).,Institut de Recerca Sant Joan de Déu (IRSJD), Barcelona, Spain (R.B.)
| | - Leif Hove-Madsen
- Biomedical Research Institute Barcelona IIBB-CSIC, CIBERCV and IIB Sant Pau, Hospital de Sant Pau, Barcelona, Spain (L.H.-M.)
| | - Enrique Alvarez-Lacalle
- Department of Physics, Universitat Politècnica de Catalunya, Barcelona, Spain (E.A.-L., B.E.)
| | - Blas Echebarria
- Department of Physics, Universitat Politècnica de Catalunya, Barcelona, Spain (E.A.-L., B.E.)
| | - S R Wayne Chen
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
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12
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Mapping Calcium Dynamics in the Heart of Zebrafish Embryos with Ratiometric Genetically Encoded Calcium Indicators. Int J Mol Sci 2020; 21:ijms21186610. [PMID: 32927644 PMCID: PMC7555812 DOI: 10.3390/ijms21186610] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 12/23/2022] Open
Abstract
Zebrafish embryos have been proposed as a cost-effective vertebrate model to study heart function. Many fluorescent genetically encoded Ca2+ indicators (GECIs) have been developed, but those with ratiometric readout seem more appropriate to image a moving organ such as the heart. Four ratiometric GECIs based on troponin C, TN-XXL, Twitch-1, Twitch-2B, and Twitch-4 were expressed transiently in the heart of zebrafish embryos. Their emission ratio reported the Ca2+ levels in both the atrium and the ventricle. We measured several kinetic parameters of the Ca2+ transients: systolic and diastolic ratio, the amplitude of the systolic Ca2+ rise, the heart rate, as well as the rise and decay times and slopes. The systolic ratio change decreased in cells expressing high biosensor concentration, possibly caused by Ca2+ buffering. The GECIs were able to report the effect of nifedipine and propranolol on the heart, which resulted in changes in heart rate, diastolic and systolic Ca2+ levels, and Ca2+ kinetics. As a result, Twitch-1 and Twitch-4 (Kd 0.25 and 2.8 µM, respectively) seem the most promising GECIs for generating transgenic zebrafish lines, which could be used for modeling heart disorders, for drug screening, and for cardiotoxicity assessment during drug development.
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13
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Physiological phenotyping of the adult zebrafish heart. Mar Genomics 2020; 49:100701. [DOI: 10.1016/j.margen.2019.100701] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 08/11/2019] [Accepted: 08/13/2019] [Indexed: 12/27/2022]
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14
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Hull CM, Genge CE, Hobbs Y, Rayani K, Lin E, Gunawan M, Shafaattalab S, Tibbits GF, Claydon TW. Investigating the utility of adult zebrafish ex vivo whole hearts to pharmacologically screen hERG channel activator compounds. Am J Physiol Regul Integr Comp Physiol 2019; 317:R921-R931. [PMID: 31664867 DOI: 10.1152/ajpregu.00190.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There is significant interest in the potential utility of small-molecule activator compounds to mitigate cardiac arrhythmia caused by loss of function of hERG1a voltage-gated potassium channels. Zebrafish (Danio rerio) have been proposed as a cost-effective, high-throughput drug-screening model to identify compounds that cause hERG1a dysfunction. However, there are no reports on the effects of hERG1a activator compounds in zebrafish and consequently on the utility of the model to screen for potential gain-of-function therapeutics. Here, we examined the effects of hERG1a blocker and types 1 and 2 activator compounds on isolated zkcnh6a (zERG3) channels in the Xenopus oocyte expression system as well as action potentials recorded from ex vivo adult zebrafish whole hearts using optical mapping. Our functional data from isolated zkcnh6a channels show that under the conditions tested, these channels are blocked by hERG1a channel blockers (dofetilide and terfenadine), and activated by type 1 (RPR260243) and type 2 (NS1643, PD-118057) hERG1a activators with higher affinity than hKCNH2a channels (except NS1643), with differences accounted for by different biophysical properties in the two channels. In ex vivo zebrafish whole hearts, two of the three hERG1a activators examined caused abbreviation of the action potential duration (APD), whereas hERG1a blockers caused APD prolongation. These data represent, to our knowledge, the first pharmacological characterization of isolated zkcnh6a channels and the first assessment of hERG enhancing therapeutics in zebrafish. Our findings lead us to suggest that the zebrafish ex vivo whole heart model serves as a valuable tool in the screening of hKCNH2a blocker and activator compounds.
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Affiliation(s)
- Christina M Hull
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Christine E Genge
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Yuki Hobbs
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Kaveh Rayani
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Eric Lin
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Marvin Gunawan
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Sanam Shafaattalab
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Glen F Tibbits
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Tom W Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
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15
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Brodehl A, Rezazadeh S, Williams T, Munsie NM, Liedtke D, Oh T, Ferrier R, Shen Y, Jones SJM, Stiegler AL, Boggon TJ, Duff HJ, Friedman JM, Gibson WT, Childs SJ, Gerull B. Mutations in ILK, encoding integrin-linked kinase, are associated with arrhythmogenic cardiomyopathy. Transl Res 2019; 208:15-29. [PMID: 30802431 PMCID: PMC7412573 DOI: 10.1016/j.trsl.2019.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/17/2019] [Accepted: 02/12/2019] [Indexed: 12/11/2022]
Abstract
Arrhythmogenic cardiomyopathy is a genetic heart muscle disorder characterized by fibro-fatty replacement of cardiomyocytes leading to life-threatening ventricular arrhythmias, heart failure, and sudden cardiac death. Mutations in genes encoding cardiac junctional proteins are known to cause about half of cases, while remaining genetic causes are unknown. Using exome sequencing, we identified 2 missense variants (p.H33N and p.H77Y) that were predicted to be damaging in the integrin-linked kinase (ILK) gene in 2 unrelated families. The p.H33N variant was found to be de novo. ILK links integrins and the actin cytoskeleton, and is essential for the maintenance of normal cardiac function. Both of the new variants are located in the ILK ankyrin repeat domain, which binds to the first LIM domain of the adaptor proteins PINCH1 and PINCH2. In silico binding studies proposed that the human variants disrupt the ILK-PINCH complex. Recombinant mutant ILK expressed in H9c2 rat myoblast cells shows aberrant prominent cytoplasmic localization compared to the wild-type. Expression of human wild-type and mutant ILK under the control of the cardiac-specific cmlc2 promotor in zebrafish shows that p.H77Y and p.P70L, a variant previously reported in a dilated cardiomyopathy family, cause cardiac dysfunction and death by about 2-3 weeks of age. Our findings provide genetic and functional evidence that ILK is a cardiomyopathy disease gene and highlight its relevance for diagnosis and genetic counseling of inherited cardiomyopathies.
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Affiliation(s)
- Andreas Brodehl
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Saman Rezazadeh
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Tatjana Williams
- Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Nicole M Munsie
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Daniel Liedtke
- Institute of Human Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Tracey Oh
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Raechel Ferrier
- Department of Medical Genetics, Alberta Health Services, Calgary, Alberta, Canada
| | - Yaoqing Shen
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Amy L Stiegler
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - William T Gibson
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | | | - Sarah J Childs
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Brenda Gerull
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada; Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany.
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16
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Ravens U. Ionic basis of cardiac electrophysiology in zebrafish compared to human hearts. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:38-44. [DOI: 10.1016/j.pbiomolbio.2018.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/23/2018] [Accepted: 06/15/2018] [Indexed: 12/14/2022]
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17
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Rayani K, Lin E, Craig C, Lamothe M, Shafaattalab S, Gunawan M, Li AY, Hove-Madsen L, Tibbits GF. Zebrafish as a model of mammalian cardiac function: Optically mapping the interplay of temperature and rate on voltage and calcium dynamics. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:69-90. [DOI: 10.1016/j.pbiomolbio.2018.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 12/27/2022]
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18
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van Opbergen CJ, van der Voorn SM, Vos MA, de Boer TP, van Veen TA. Cardiac Ca2+ signalling in zebrafish: Translation of findings to man. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:45-58. [DOI: 10.1016/j.pbiomolbio.2018.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 05/04/2018] [Indexed: 02/07/2023]
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19
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Zhang H, Dvornikov AV, Huttner IG, Ma X, Santiago CF, Fatkin D, Xu X. A Langendorff-like system to quantify cardiac pump function in adult zebrafish. Dis Model Mech 2018; 11:dmm.034819. [PMID: 30012855 PMCID: PMC6177000 DOI: 10.1242/dmm.034819] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/10/2018] [Indexed: 12/22/2022] Open
Abstract
Zebrafish are increasingly used as a vertebrate model to study human cardiovascular disorders. Although heart structure and function are readily visualized in zebrafish embryos because of their optical transparency, the lack of effective tools for evaluating the hearts of older, nontransparent fish has been a major limiting factor. The recent development of high-frequency echocardiography has been an important advance for in vivo cardiac assessment, but it necessitates anesthesia and has limited ability to study acute interventions. We report the development of an alternative experimental ex vivo technique for quantifying heart size and function that resembles the Langendorff heart preparations that have been widely used in mammalian models. Dissected adult zebrafish hearts were perfused with a calcium-containing buffer, and a beat frequency was maintained with electrical stimulation. The impact of pacing frequency, flow rate and perfusate calcium concentration on ventricular performance (including end-diastolic and end-systolic volumes, ejection fraction, radial strain, and maximal velocities of shortening and relaxation) were evaluated and optimal conditions defined. We determined the effects of age on heart function in wild-type male and female zebrafish, and successfully detected hypercontractile and hypocontractile responses after adrenergic stimulation or doxorubicin treatment, respectively. Good correlations were found between indices of cardiac contractility obtained with high-frequency echocardiography and with the ex vivo technique in a subset of fish studied with both methods. The ex vivo beating heart preparation is a valuable addition to the cardiac function tool kit that will expand the use of adult zebrafish for cardiovascular research.
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Affiliation(s)
- Hong Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55902, USA.,Cardiovascular Surgery Department, the Second Xiangya Hospital of Central South University, Changsha 410011, China
| | - Alexey V Dvornikov
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55902, USA
| | - Inken G Huttner
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia.,St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Xiao Ma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55902, USA.,Clinical and Translational Sciences Track, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic College of Medicine and Science, Rochester, MN 55092, USA
| | - Celine F Santiago
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia.,St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Diane Fatkin
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia.,St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia.,Cardiology Department, St. Vincent's Hospital, Sydney, NSW 2010, Australia
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55902, USA
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20
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Skarsfeldt MA, Bomholtz SH, Lundegaard PR, Lopez-Izquierdo A, Tristani-Firouzi M, Bentzen BH. Atrium-specific ion channels in the zebrafish-A role of I KACh in atrial repolarization. Acta Physiol (Oxf) 2018; 223:e13049. [PMID: 29412518 DOI: 10.1111/apha.13049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 12/16/2022]
Abstract
AIM The zebrafish has emerged as a novel model for investigating cardiac physiology and pathology. The aim of this study was to investigate the atrium-specific ion channels responsible for shaping the atrial cardiac action potential in zebrafish. METHODS Using quantitative polymerase chain reaction, we assessed the expression level of atrium-specific potassium channels. The functional role of these channels was studied by patch clamp experiments on isolated atrial and ventricular cardiomyocytes and by optical mapping of explanted adult zebrafish hearts. Finally, surface ECGs were recorded to establish possible in vivo roles of atrial ion channels. RESULTS In isolated adult zebrafish hearts, we identified the expression of kcnk3, kcnk9, kcnn1, kcnn2, kcnn3, kcnj3 and kcnj5, the genes that encode the atrium-specific K2P , KCa 2.x and Kir 3.1/4 (KACh ) ion channels. The electrophysiological data indicate that the acetylcholine-activated inward-rectifying current, IKACh, plays a major role in the zebrafish atrium, whereas K2P 3.1/9.1 and KCa 2.x channels do not appear to be involved in regulating the action potential in the zebrafish heart. CONCLUSION We demonstrate that the acetylcholine-activated inward-rectifying current (IKACh ) current plays a major role in the zebrafish atrium and that the zebrafish could potentially be a cost-effective and reliable model for pharmacological testing of atrium-specific IKACh modulating compounds.
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Affiliation(s)
- M. A. Skarsfeldt
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen N Denmark
- Nora Eccles Harrison Cardiovascular Research and Training Institute; University of Utah; Salt Lake City UT USA
| | - S. H. Bomholtz
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen N Denmark
| | - P. R. Lundegaard
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen N Denmark
| | - A. Lopez-Izquierdo
- Nora Eccles Harrison Cardiovascular Research and Training Institute; University of Utah; Salt Lake City UT USA
| | - M. Tristani-Firouzi
- Nora Eccles Harrison Cardiovascular Research and Training Institute; University of Utah; Salt Lake City UT USA
| | - B. H. Bentzen
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen N Denmark
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21
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Haverinen J, Hassinen M, Dash SN, Vornanen M. Expression of calcium channel transcripts in the zebrafish heart: dominance of T-type channels. ACTA ACUST UNITED AC 2018; 221:jeb.179226. [PMID: 29739832 DOI: 10.1242/jeb.179226] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/06/2018] [Indexed: 12/13/2022]
Abstract
Calcium channels are necessary for cardiac excitation-contraction (E-C) coupling, but Ca2+ channel composition of fish hearts is still largely unknown. To this end, we determined transcript expression of Ca2+ channels in the heart of zebrafish (Danio rerio), a popular model species. Altogether, 18 Ca2+ channel α-subunit genes were expressed in both atrium and ventricle. Transcripts for 7 L-type (Cav1.1a, Cav1.1b, Cav1.2, Cav1.3a, Cav1.3b, Cav1.4a, Cav1.4b), 5 T-type (Cav3.1, Cav3.2a, Cav3.2b, Cav3.3a, Cav3.3b) and 6 P/Q-, N- and R-type (Cav2.1a, Cav2.1b, Cav2.2a, Cav2.2b, Cav2.3a, Cav2.3b) Ca2+ channels were expressed. In the ventricle, T-type channels formed 54.9%, L-type channels 41.1% and P/Q-, N- and R-type channels 4.0% of the Ca2+ channel transcripts. In the atrium, the relative expression of T-type and L-type Ca2+ channel transcripts was 64.1% and 33.8%, respectively (others accounted for 2.1%). Thus, at the transcript level, T-type Ca2+ channels are prevalent in zebrafish atrium and ventricle. At the functional level, peak densities of ventricular T-type (ICaT) and L-type (ICaL) Ca2+ current were 6.3±0.8 and 7.7±0.8 pA pF-1, respectively. ICaT mediated a sizeable sarcolemmal Ca2+ influx into ventricular myocytes: the increment in total cellular Ca2+ content via ICaT was 41.2±7.3 µmol l-1, which was 31.7% of the combined Ca2+ influx (129 µmol l-1) via ICaT and ICaL (88.5±20.5 µmol l-1). The diversity of expressed Ca2+ channel genes in zebrafish heart is high, but dominated by the members of the T-type subfamily. The large ventricular ICaT is likely to play a significant role in E-C coupling.
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Affiliation(s)
- Jaakko Haverinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
| | - Minna Hassinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
| | - Surjya Narayan Dash
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland.,Neuroscience Center and Department of Anatomy, Faculty of Medicine, University of Helsinki, PO Box 63, 00014 Helsinki, Finland
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
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22
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MacDonald EA, Stoyek MR, Rose RA, Quinn TA. Intrinsic regulation of sinoatrial node function and the zebrafish as a model of stretch effects on pacemaking. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:198-211. [PMID: 28743586 DOI: 10.1016/j.pbiomolbio.2017.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/18/2022]
Abstract
Excitation of the heart occurs in a specialised region known as the sinoatrial node (SAN). Tight regulation of SAN function is essential for the maintenance of normal heart rhythm and the response to (patho-)physiological changes. The SAN is regulated by extrinsic (central nervous system) and intrinsic (neurons, peptides, mechanics) factors. The positive chronotropic response to stretch in particular is essential for beat-by-beat adaptation to changes in hemodynamic load. Yet, the mechanism of this stretch response is unknown, due in part to the lack of an appropriate experimental model for targeted investigations. We have been investigating the zebrafish as a model for the study of intrinsic regulation of SAN function. In this paper, we first briefly review current knowledge of the principal components of extrinsic and intrinsic SAN regulation, derived primarily from experiments in mammals, followed by a description of the zebrafish as a novel experimental model for studies of intrinsic SAN regulation. This mini-review is followed by an original investigation of the response of the zebrafish isolated SAN to controlled stretch. Stretch causes an immediate and continuous increase in beating rate in the zebrafish isolated SAN. This increase reaches a maximum part way through a period of sustained stretch, with the total change dependent on the magnitude and direction of stretch. This is comparable to what occurs in isolated SAN from most mammals (including human), suggesting that the zebrafish is a novel experimental model for the study of mechanisms involved in the intrinsic regulation of SAN function by mechanical effects.
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Affiliation(s)
- Eilidh A MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Matthew R Stoyek
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada; School of Biomedical Engineering, Dalhousie University, Halifax, Canada.
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Sarmah S, Marrs JA. Zebrafish as a Vertebrate Model System to Evaluate Effects of Environmental Toxicants on Cardiac Development and Function. Int J Mol Sci 2016; 17:ijms17122123. [PMID: 27999267 PMCID: PMC5187923 DOI: 10.3390/ijms17122123] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/04/2016] [Accepted: 12/12/2016] [Indexed: 12/16/2022] Open
Abstract
Environmental pollution is a serious problem of the modern world that possesses a major threat to public health. Exposure to environmental pollutants during embryonic development is particularly risky. Although many pollutants have been verified as potential toxicants, there are new chemicals in the environment that need assessment. Heart development is an extremely sensitive process, which can be affected by environmentally toxic molecule exposure during embryonic development. Congenital heart defects are the most common life-threatening global health problems, and the etiology is mostly unknown. The zebrafish has emerged as an invaluable model to examine substance toxicity on vertebrate development, particularly on cardiac development. The zebrafish offers numerous advantages for toxicology research not found in other model systems. Many laboratories have used the zebrafish to study the effects of widespread chemicals in the environment on heart development, including pesticides, nanoparticles, and various organic pollutants. Here, we review the uses of the zebrafish in examining effects of exposure to external molecules during embryonic development in causing cardiac defects, including chemicals ubiquitous in the environment and illicit drugs. Known or potential mechanisms of toxicity and how zebrafish research can be used to provide mechanistic understanding of cardiac defects are discussed.
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Affiliation(s)
- Swapnalee Sarmah
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA.
| | - James A Marrs
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA.
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Chan HYS, Cheung MC, Gao Y, Miller AL, Webb SE. Expression and reconstitution of the bioluminescent Ca(2+) reporter aequorin in human embryonic stem cells, and exploration of the presence of functional IP3 and ryanodine receptors during the early stages of their differentiation into cardiomyocytes. SCIENCE CHINA-LIFE SCIENCES 2016; 59:811-24. [PMID: 27430888 DOI: 10.1007/s11427-016-5094-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 05/06/2016] [Indexed: 02/05/2023]
Abstract
In order to develop a novel method of visualizing possible Ca(2+) signaling during the early differentiation of hESCs into cardiomyocytes and avoid some of the inherent problems associated with using fluorescent reporters, we expressed the bioluminescent Ca(2+) reporter, apo-aequorin, in HES2 cells and then reconstituted active holo-aequorin by incubation with f-coelenterazine. The temporal nature of the Ca(2+) signals generated by the holo-f-aequorin-expressing HES2 cells during the earliest stages of differentiation into cardiomyocytes was then investigated. Our data show that no endogenous Ca(2+) transients (generated by release from intracellular stores) were detected in 1-12-day-old cardiospheres but transients were generated in cardiospheres following stimulation with KCl or CaCl2, indicating that holo-f-aequorin was functional in these cells. Furthermore, following the addition of exogenous ATP, an inositol trisphosphate receptor (IP3R) agonist, small Ca(2+) transients were generated from day 1 onward. That ATP was inducing Ca(2+) release from functional IP3Rs was demonstrated by treatment with 2-APB, a known IP3R antagonist. In contrast, following treatment with caffeine, a ryanodine receptor (RyR) agonist, a minimal Ca(2+) response was observed at day 8 of differentiation only. Thus, our data indicate that unlike RyRs, IP3Rs are present and continually functional at these early stages of cardiomyocyte differentiation.
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Affiliation(s)
- Harvey Y S Chan
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, China
| | - Man Chun Cheung
- Stem Cell & Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yi Gao
- Stem Cell & Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Andrew L Miller
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, China
- Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Sarah E Webb
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, China.
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Genge CE, Lin E, Lee L, Sheng X, Rayani K, Gunawan M, Stevens CM, Li AY, Talab SS, Claydon TW, Hove-Madsen L, Tibbits GF. The Zebrafish Heart as a Model of Mammalian Cardiac Function. Rev Physiol Biochem Pharmacol 2016; 171:99-136. [PMID: 27538987 DOI: 10.1007/112_2016_5] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Zebrafish (Danio rerio) are widely used as vertebrate model in developmental genetics and functional genomics as well as in cardiac structure-function studies. The zebrafish heart has been increasingly used as a model of human cardiac function, in part, due to the similarities in heart rate and action potential duration and morphology with respect to humans. The teleostian zebrafish is in many ways a compelling model of human cardiac function due to the clarity afforded by its ease of genetic manipulation, the wealth of developmental biological information, and inherent suitability to a variety of experimental techniques. However, in addition to the numerous advantages of the zebrafish system are also caveats related to gene duplication (resulting in paralogs not present in human or other mammals) and fundamental differences in how zebrafish hearts function. In this review, we discuss the use of zebrafish as a cardiac function model through the use of techniques such as echocardiography, optical mapping, electrocardiography, molecular investigations of excitation-contraction coupling, and their physiological implications relative to that of the human heart. While some of these techniques (e.g., echocardiography) are particularly challenging in the zebrafish because of diminutive size of the heart (~1.5 mm in diameter) critical information can be derived from these approaches and are discussed in detail in this article.
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Affiliation(s)
- Christine E Genge
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Eric Lin
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Ling Lee
- BC Children's Hospital Research Institute, Vancouver, BC, Canada, V5Z 4H4
| | - XiaoYe Sheng
- BC Children's Hospital Research Institute, Vancouver, BC, Canada, V5Z 4H4
| | - Kaveh Rayani
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Marvin Gunawan
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Charles M Stevens
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6.,BC Children's Hospital Research Institute, Vancouver, BC, Canada, V5Z 4H4
| | - Alison Yueh Li
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Sanam Shafaat Talab
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Thomas W Claydon
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - Leif Hove-Madsen
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6.,Cardiovascular Research Centre CSIC-ICCC, Hospital de Sant Pau, Barcelona, Spain
| | - Glen F Tibbits
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6. .,BC Children's Hospital Research Institute, Vancouver, BC, Canada, V5Z 4H4.
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26
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Jaźwińska A, Sallin P. Regeneration versus scarring in vertebrate appendages and heart. J Pathol 2016; 238:233-46. [PMID: 26414617 PMCID: PMC5057359 DOI: 10.1002/path.4644] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/15/2015] [Accepted: 09/18/2015] [Indexed: 12/15/2022]
Abstract
Injuries to complex human organs, such as the limbs and the heart, result in pathological conditions, for which we often lack adequate treatments. While modern regenerative approaches are based on the transplantation of stem cell-derived cells, natural regeneration in lower vertebrates, such as zebrafish and newts, relies predominantly on the intrinsic plasticity of mature tissues. This property involves local activation of the remaining material at the site of injury to promote cell division, cell migration and complete reproduction of the missing structure. It remains an unresolved question why adult mammals are not equally competent to reactivate morphogenetic programmes. Although organ regeneration depends strongly on the proliferative properties of cells in the injured tissue, it is apparent that various organismic factors, such as innervation, vascularization, hormones, metabolism and the immune system, can affect this process. Here, we focus on a correlation between the regenerative capacity and cellular specialization in the context of functional demands, as illustrated by appendages and heart in diverse vertebrates. Elucidation of the differences between homologous regenerative and non-regenerative tissues from various animal models is essential for understanding the applicability of lessons learned from the study of regenerative biology to clinical strategies for the treatment of injured human organs.
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Affiliation(s)
- Anna Jaźwińska
- Department of Biology, University of Fribourg, Switzerland
| | - Pauline Sallin
- Department of Biology, University of Fribourg, Switzerland
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27
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Abstract
The zebrafish (Danio rerio) has become a popular model for human cardiac diseases and pharmacology including cardiac arrhythmias and its electrophysiological basis. Notably, the phenotype of zebrafish cardiac action potential is similar to the human cardiac action potential in that both have a long plateau phase. Also the major inward and outward current systems are qualitatively similar in zebrafish and human hearts. However, there are also significant differences in ionic current composition between human and zebrafish hearts, and the molecular basis and pharmacological properties of human and zebrafish cardiac ionic currents differ in several ways. Cardiac ionic currents may be produced by non-orthologous genes in zebrafish and humans, and paralogous gene products of some ion channels are expressed in the zebrafish heart. More research on molecular basis of cardiac ion channels, and regulation and drug sensitivity of the cardiac ionic currents are needed to enable rational use of the zebrafish heart as an electrophysiological model for the human heart.
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Affiliation(s)
- Matti Vornanen
- a Department of Biology , University of Eastern Finland , Joensuu , Finland
| | - Minna Hassinen
- a Department of Biology , University of Eastern Finland , Joensuu , Finland
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28
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Kubly KL, Stecyk JAW. Temperature-dependence of L-type Ca(2+) current in ventricular cardiomyocytes of the Alaska blackfish (Dallia pectoralis). J Comp Physiol B 2015; 185:845-58. [PMID: 26439127 DOI: 10.1007/s00360-015-0931-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/04/2015] [Accepted: 09/07/2015] [Indexed: 01/12/2023]
Abstract
To lend insight into the overwintering strategy of the Alaska blackfish (Dallia pectoralis), we acclimated fish to 15 or 5 °C and then utilized whole-cell patch clamp to characterize the effects of thermal acclimation and acute temperature change on the density and kinetics of ventricular L-type Ca(2+) current (I Ca). Peak I Ca density at 5 °C (-1.1 ± 0.1 pA pF(-1)) was 1/8th that at 15 °C (-8.8 ± 0.6 pA pF(-1)). However, alterations of the Ca(2+)- and voltage-dependent inactivation properties of L-type Ca(2+) channels partially compensated against the decrease. The time constant tau (τ) for the kinetics of inactivation of I Ca was ~4.5 times greater at 5 °C than at 15 °C, and the voltage for half-maximal inactivation was shifted from -23.3 ± 1.0 mV at 15 °C to -19.8 ± 1.2 mV at 5 °C. These modifications increase the open probability of the channel and culminate in an approximate doubling of the L-type Ca(2+) window current, which contributes to approximately 15% of the maximal Ca(2+) conductance at 5 °C. Consequently, the charge density of I Ca (Q Ca) and the total Ca(2+) transferred through the L-type Ca(2+) channels (Δ[Ca(2+)]) were not as severely reduced at 5 °C as compared to peak I Ca density. In combination, the results suggest that while the Alaska blackfish substantially down-regulates I Ca with acclimation to low temperature, there is sufficient compensation in the kinetics of the L-type Ca(2+) channel to support the level of cardiac performance required for the fish to remain active throughout the winter.
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Affiliation(s)
- Kerry L Kubly
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Conoco Philips Integrated Science Building, Anchorage, AK, 99508, USA.
| | - Jonathan A W Stecyk
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Conoco Philips Integrated Science Building, Anchorage, AK, 99508, USA
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29
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Haustein M, Hannes T, Trieschmann J, Verhaegh R, Köster A, Hescheler J, Brockmeier K, Adelmann R, Khalil M. Excitation-contraction coupling in zebrafish ventricular myocardium is regulated by trans-sarcolemmal Ca2+ influx and sarcoplasmic reticulum Ca2+ release. PLoS One 2015; 10:e0125654. [PMID: 25938412 PMCID: PMC4418605 DOI: 10.1371/journal.pone.0125654] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/17/2015] [Indexed: 01/19/2023] Open
Abstract
Zebrafish (Danio rerio) have become a popular model in cardiovascular research mainly due to identification of a large number of mutants with structural defects. In recent years, cardiomyopathies and other diseases influencing contractility of the heart have been studied in zebrafish mutants. However, little is known about the regulation of contractility of the zebrafish heart on a tissue level. The aim of the present study was to elucidate the role of trans-sarcolemmal Ca2+-flux and sarcoplasmic reticulum Ca2+-release in zebrafish myocardium. Using isometric force measurements of fresh heart slices, we characterised the effects of changes of the extracellular Ca2+-concentration, trans-sarcolemmal Ca2+-flux via L-type Ca2+-channels and Na+-Ca2+-exchanger, and Ca2+-release from the sarcoplasmic reticulum as well as beating frequency and β-adrenergic stimulation on contractility of adult zebrafish myocardium. We found an overall negative force-frequency relationship (FFR). Inhibition of L-type Ca2+-channels by verapamil (1 μM) decreased force of contraction to 22±7% compared to baseline (n=4, p<0.05). Ni2+ was the only substance to prolong relaxation (5 mM, time after peak to 50% relaxation: 73±3 ms vs. 101±8 ms, n=5, p<0.05). Surprisingly though, inhibition of the sarcoplasmic Ca2+-release decreased force development to 54±3% in ventricular (n=13, p<0.05) and to 52±8% in atrial myocardium (n=5, p<0.05) suggesting a substantial role of SR Ca2+-release in force generation. In line with this finding, we observed significant post pause potentiation after pauses of 5 s (169±7% force compared to baseline, n=8, p<0.05) and 10 s (198±9% force compared to baseline, n=5, p<0.05) and mildly positive lusitropy after β-adrenergic stimulation. In conclusion, force development in adult zebrafish ventricular myocardium requires not only trans-sarcolemmal Ca2+-flux, but also intact sarcoplasmic reticulum Ca2+-cycling. In contrast to mammals, FFR is strongly negative in the zebrafish heart. These aspects need to be considered when using zebrafish to model human diseases of myocardial contractility.
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Affiliation(s)
- Moritz Haustein
- Department of Paediatric Cardiology, Cologne Heart Centre, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
| | - Tobias Hannes
- Department of Paediatric Cardiology, Cologne Heart Centre, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
- Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
- * E-mail:
| | - Jan Trieschmann
- Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
| | - Rabea Verhaegh
- Institute of Physiological Chemistry, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
| | - Annette Köster
- Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
| | - Jürgen Hescheler
- Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
| | - Konrad Brockmeier
- Department of Paediatric Cardiology, Cologne Heart Centre, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
| | - Roland Adelmann
- Department of Paediatric Cardiology, Cologne Heart Centre, Medical Faculty, University of Cologne, Cologne, North Rhine-Westphalia, Germany
| | - Markus Khalil
- Department of Paediatric Cardiology, University Hospital of Giessen and Marburg, University of Giessen and Marburg, Giessen, Hessen, Germany
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Lin E, Craig C, Lamothe M, Sarunic MV, Beg MF, Tibbits GF. Construction and use of a zebrafish heart voltage and calcium optical mapping system, with integrated electrocardiogram and programmable electrical stimulation. Am J Physiol Regul Integr Comp Physiol 2015; 308:R755-68. [PMID: 25740339 DOI: 10.1152/ajpregu.00001.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 02/26/2015] [Indexed: 12/31/2022]
Abstract
Zebrafish are increasingly being used as a model of vertebrate cardiology due to mammalian-like cardiac properties in many respects. The size and fecundity of zebrafish make them suitable for large-scale genetic and pharmacological screening. In larger mammalian hearts, optical mapping is often used to investigate the interplay between voltage and calcium dynamics and to investigate their respective roles in arrhythmogenesis. This report outlines the construction of an optical mapping system for use with zebrafish hearts, using the voltage-sensitive dye RH 237 and the calcium indicator dye Rhod-2 using two industrial-level CCD cameras. With the use of economical cameras and a common 532-nm diode laser for excitation, the rate dependence of voltage and calcium dynamics within the atrial and ventricular compartments can be simultaneously determined. At 140 beats/min, the atrial action potential duration was 36 ms and the transient duration was 53 ms. With the use of a programmable electrical stimulator, a shallow rate dependence of 3 and 4 ms per 100 beats/min was observed, respectively. In the ventricle the action potential duration was 109 ms and the transient duration was 124 ms, with a steeper rate dependence of 12 and 16 ms per 100 beats/min. Synchronous electrocardiograms and optical mapping recordings were recorded, in which the P-wave aligns with the atrial voltage peak and R-wave aligns with the ventricular peak. A simple optical pathway and imaging chamber are detailed along with schematics for the in-house construction of the electrocardiogram amplifier and electrical stimulator. Laboratory procedures necessary for zebrafish heart isolation, cannulation, and loading are also presented.
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Affiliation(s)
- Eric Lin
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Calvin Craig
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Marcel Lamothe
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Marinko V Sarunic
- Biomedical Optics Research Group, School of Engineering Science, Simon Fraser University, Burnaby
| | - Mirza Faisal Beg
- Medical Image Analysis Lab, School of Engineering Science, Simon Fraser University, Burnaby, Canada; and
| | - Glen F Tibbits
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada; Cardiovascular Sciences, Child and Family Research Institute, Vancouver, Canada
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31
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Alday A, Alonso H, Gallego M, Urrutia J, Letamendia A, Callol C, Casis O. Ionic channels underlying the ventricular action potential in zebrafish embryo. Pharmacol Res 2014; 84:26-31. [DOI: 10.1016/j.phrs.2014.03.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/28/2014] [Accepted: 03/31/2014] [Indexed: 01/31/2023]
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32
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Korajoki H, Vornanen M. Species- and chamber-specific responses of 12 kDa FK506-binding protein to temperature in fish heart. FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:539-549. [PMID: 24048915 DOI: 10.1007/s10695-013-9864-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/10/2013] [Indexed: 06/02/2023]
Abstract
The sarcoplasmic reticulum (SR) Ca(2+) release channel or ryanodine receptor (RyR) of the vertebrate heart is regulated by the FK506-binding proteins, FKBP12 and FKBP12.6. This study examines whether temperature-related changes in the SR function of fish hearts are associated with changes in FKBP12 expression. For this purpose, a polyclonal antibody against trout FKBP12 was used to compare FKPB12 expression in cold-acclimated (4 °C, CA) and warm-acclimated (18 °C, WA) rainbow trout (Oncorhynchus mykiss), burbot (Lota lota) and crucian carp (Carassius carassius) hearts. FKBP12 expression was modulated in a species- and tissue-specific manner. Temperature acclimation affected FKBP12 expression only in atrial tissue. Changes in the ventricular FKBP12 expression were not detected in any of the fish species. In the atria of rainbow trout and crucian carp, temperature acclimation produced opposite thermal responses: FKBP12 increased in the trout atrium and decreased in the crucian carp atrium under cold acclimation. In the burbot heart, chronic temperature changes did not affect cardiac FKBP12 levels. Expression of FKBP12 mRNA in rainbow trout and crucian carp hearts suggests that the transcript levels are higher in the ventricle than in the atrium and are elevated by cold acclimation in trout, but not in crucian carp. Since FKBP12 is known to increase the Ca(2+) sensitivity of cardiac RyRs and thereby the opening frequency of the Ca(2+) release channels, temperature-related changes in FKBP12 expression may modify the SR function in excitation-contraction coupling. The cold-induced increase in FKBP12 in the trout atrium and decrease in the crucian carp atrium are consistent with the previously noted increase and decrease, respectively, of SR Ca(2+) stores in cardiac contraction in these species.
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Affiliation(s)
- Hanna Korajoki
- Department of Biology, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland,
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33
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Lin E, Ribeiro A, Ding W, Hove-Madsen L, Sarunic MV, Beg MF, Tibbits GF. Optical mapping of the electrical activity of isolated adult zebrafish hearts: acute effects of temperature. Am J Physiol Regul Integr Comp Physiol 2014; 306:R823-36. [PMID: 24671241 DOI: 10.1152/ajpregu.00002.2014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The zebrafish (Danio rerio) has emerged as an important model for developmental cardiovascular (CV) biology; however, little is known about the cardiac function of the adult zebrafish enabling it to be used as a model of teleost CV biology. Here, we describe electrophysiological parameters, such as heart rate (HR), action potential duration (APD), and atrioventricular (AV) delay, in the zebrafish heart over a range of physiological temperatures (18-28°C). Hearts were isolated and incubated in a potentiometric dye, RH-237, enabling electrical activity assessment in several distinct regions of the heart simultaneously. Integration of a rapid thermoelectric cooling system facilitated the investigation of acute changes in temperature on critical electrophysiological parameters in the zebrafish heart. While intrinsic HR varied considerably between fish, the ex vivo preparation exhibited impressively stable HRs and sinus rhythm for more than 5 h, with a mean HR of 158 ± 9 bpm (means ± SE; n = 20) at 28°C. Atrial and ventricular APDs at 50% repolarization (APD50) were 33 ± 1 ms and 98 ± 2 ms, respectively. Excitation originated in the atrium, and there was an AV delay of 61 ± 3 ms prior to activation of the ventricle at 28°C. APD and AV delay varied between hearts beating at unique HRs; however, APD and AV delay did not appear to be statistically dependent on intrinsic basal HR, likely due to the innate beat-to-beat variability within each heart. As hearts were cooled to 18°C (by 1°C increments), HR decreased by ~40%, and atrial and ventricular APD50 increased by a factor of ~3 and 2, respectively. The increase in APD with cooling was disproportionate at different levels of repolarization, indicating unique temperature sensitivities for ion currents at different phases of the action potential. The effect of temperature was more apparent at lower levels of repolarization and, as a whole, the atrial APD was the cardiac parameter most affected by acute temperature change. In conclusion, this study describes a preparation enabling the in-depth analysis of transmembrane potential dynamics in whole zebrafish hearts. Because the zebrafish offers some critical advantages over the murine model for cardiac electrophysiology, optical mapping studies utilizing zebrafish offer insightful information into the understanding and treatment of human cardiac arrhythmias, as well as serving as a model for other teleosts.
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Affiliation(s)
- Eric Lin
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Amanda Ribeiro
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Weiguang Ding
- Medical Image Analysis Laboratory, School of Engineering Science, Simon Fraser University, Burnaby, Canada
| | - Leif Hove-Madsen
- Cardiovascular Research Centre, CSIC-ICCC, Hospital de Sant Pau, Barcelona, Spain
| | - Marinko V Sarunic
- Biomedical Optics Research Group, School of Engineering Science, Simon Fraser University, Burnaby, Canada; and
| | - Mirza Faisal Beg
- Medical Image Analysis Laboratory, School of Engineering Science, Simon Fraser University, Burnaby, Canada
| | - Glen F Tibbits
- Molecular Cardiac Physiology Group, Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada; Cardiovascular Sciences, Child and Family Research Institute, Vancouver, Canada
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34
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Dvornikov AV, Dewan S, Alekhina OV, Pickett FB, de Tombe PP. Novel approaches to determine contractile function of the isolated adult zebrafish ventricular cardiac myocyte. J Physiol 2014; 592:1949-56. [PMID: 24591576 DOI: 10.1113/jphysiol.2014.270678] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The zebrafish (Danio rerio) has been used extensively in cardiovascular biology, but mainly in the study of heart development. The relative ease of its genetic manipulation may indicate the suitability of this species as a cost-effective model system for the study of cardiac contractile biology. However, whether the zebrafish heart is an appropriate model system for investigations pertaining to mammalian cardiac contractile structure-function relationships remains to be resolved. Myocytes were isolated from adult zebrafish hearts by enzymatic digestion, attached to carbon rods, and twitch force and intracellular Ca(2+) were measured. We observed the modulation of twitch force, but not of intracellular Ca(2+), by both extracellular [Ca(2+)] and sarcomere length. In permeabilized cells/myofibrils, we found robust myofilament length-dependent activation. Moreover, modulation of myofilament activation-relaxation and force redevelopment kinetics by varied Ca(2+) activation levels resembled that found previously in mammalian myofilaments. We conclude that the zebrafish is a valid model system for the study of cardiac contractile structure-function relationships.
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Affiliation(s)
- Alexey V Dvornikov
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 South First Avenue, Maywood, IL 60153, USA.
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35
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Mechanisms of Ca²+ handling in zebrafish ventricular myocytes. Pflugers Arch 2013; 465:1775-84. [PMID: 23821298 DOI: 10.1007/s00424-013-1312-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/10/2013] [Accepted: 06/12/2013] [Indexed: 12/17/2022]
Abstract
The zebrafish serves as a promising transgenic animal model that can be used to study cardiac Ca(2+) regulation. However, mechanisms of sarcoplasmic reticulum (SR) Ca(2+) handling in the zebrafish heart have not been systematically explored. We found that in zebrafish ventricular myocytes, the action potential-induced Ca(2+) transient is mainly (80 %) mediated by Ca(2+) influx via L-type Ca(2+) channels (LTCC) and only 20 % by Ca(2+) released from the SR. This small contribution of the SR to the Ca(2+) transient was not the result of depleted SR Ca(2+) load. We found that the ryanodine receptor (RyR) expression level in zebrafish myocytes was ∼72 % lower compared to rabbit myocytes. In permeabilized myocytes, increasing cytosolic [Ca(2+)] from 100 to 350 nM did not trigger SR Ca(2+) release. However, an application of a low dose of caffeine activated Ca(2+) sparks. These results show that the zebrafish cardiac RyR has low sensitivity to the mechanism of Ca(2+)-induced Ca(2+) release. Activation of protein kinase A by forskolin increased phosphorylation of the RyR in zebrafish myocardium. In half of the studied cells, an increased Ca(2+) transient by forskolin was entirely mediated by augmentation of LTCC current. In the remaining myocytes, the forskolin action was associated with an increase of both LTCC and SR Ca(2+) release. These results indicate that the mechanism of excitation-contraction coupling in zebrafish myocytes differs from the mammalian one mainly because of the small contribution of SR Ca(2+) release to the Ca(2+) transient. This difference is due to a low sensitivity of RyRs to cytosolic [Ca(2+)].
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Paavola J, Schliffke S, Rossetti S, Kuo IYT, Yuan S, Sun Z, Harris PC, Torres VE, Ehrlich BE. Polycystin-2 mutations lead to impaired calcium cycling in the heart and predispose to dilated cardiomyopathy. J Mol Cell Cardiol 2013; 58:199-208. [PMID: 23376035 PMCID: PMC3636149 DOI: 10.1016/j.yjmcc.2013.01.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 01/04/2013] [Accepted: 01/17/2013] [Indexed: 12/31/2022]
Abstract
Mutations in PKD1 and PKD2, the genes encoding the proteins polycystin-1 (PC1) and polycystin-2 (PC2), cause autosomal dominant polycystic kidney disease (ADPKD). Although the leading cause of mortality in ADPKD is cardiovascular disease, the relationship between these conditions remains poorly understood. PC2 is an intracellular calcium channel expressed in renal epithelial cells and in cardiomyocytes, and is thus hypothesized to modulate intracellular calcium signaling and affect cardiac function. Our first aim was to study cardiac function in a zebrafish model lacking PC2 (pkd2 mutants). Next, we aimed to explore the relevance of this zebrafish model to human ADPKD by examining the Mayo Clinic's ADPKD database for an association between ADPKD and idiopathic dilated cardiomyopathy (IDCM). Pkd2 mutant zebrafish showed low cardiac output and atrioventricular block. Isolated pkd2 mutant hearts displayed impaired intracellular calcium cycling and calcium alternans. These results indicate heart failure in the pkd2 mutants. In human ADPKD patients, we found IDCM to coexist frequently with ADPKD. This association was strongest in patients with PKD2 mutations. Our results demonstrate that PC2 modulates intracellular calcium cycling, contributing to the development of heart failure. In human subjects we found an association between ADPKD and IDCM and suggest that PKD mutations contribute to the development of heart failure.
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Affiliation(s)
- Jere Paavola
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
- Department of Anatomy II: Experimental Morphology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Simon Schliffke
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
- Department of Anatomy II: Experimental Morphology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Sandro Rossetti
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Ivana Y.-T. Kuo
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Shiaulou Yuan
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Zhaoxia Sun
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Peter C. Harris
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Vicente E. Torres
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Barbara E. Ehrlich
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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Abstract
This protocol describes how to isolate primary cardiomyocytes from adult zebrafish hearts and culture them for up to 4 weeks, thereby using them as an alternative to in vivo experiments. After collagenase digestion of the ventricle, cells are exposed to increasing calcium concentrations in order to obtain high-purity cardiomyocytes. The whole isolation process can be accomplished in 4-5 h. The culture conditions we established allow the cells to preserve their mature sarcomeric integrity and contractile properties. Furthermore, adult zebrafish cardiomyocytes in culture, similarly to zebrafish in vivo heart regeneration, undergo partial dedifferentiation and, in contrast to their mammalian counterparts, are able to proliferate. Our protocol enables the study of structural and functional properties in close-to-native cardiomyocytes and allows the application of in vitro techniques and assays that are not feasible to perform in living animals.
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Staudt D, Stainier D. Uncovering the molecular and cellular mechanisms of heart development using the zebrafish. Annu Rev Genet 2012; 46:397-418. [PMID: 22974299 DOI: 10.1146/annurev-genet-110711-155646] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Over the past 20 years, the zebrafish has emerged as a powerful model organism for studying cardiac development. Its ability to survive without an active circulation and amenability to forward genetics has led to the identification of numerous mutants whose study has helped elucidate new mechanisms in cardiac development. Furthermore, its transparent, externally developing embryos have allowed detailed cellular analyses of heart development. In this review, we discuss the molecular and cellular processes involved in zebrafish heart development from progenitor specification to development of the valve and the conduction system. We focus on imaging studies that have uncovered the cellular bases of heart development and on zebrafish mutants with cardiac abnormalities whose study has revealed novel molecular pathways in cardiac cell specification and tissue morphogenesis.
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Affiliation(s)
- David Staudt
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, USA
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39
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Abstract
Understanding the developmental basis of cardiac electrical activity has proven technically challenging, largely as a result of the inaccessible nature of the heart during cardiogenesis in many organisms. The emergence of the zebrafish as a model organism has availed the very earliest stages of heart formation to experimental exploration. The zebrafish also offers a robust platform for genetic and chemical screening. These tools have been exploited in screens for modifiers of cardiac electrophysiologic phenotypes and in screens for novel drugs.
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The zebrafish as a novel animal model to study the molecular mechanisms of mechano-electrical feedback in the heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:154-65. [PMID: 22835662 DOI: 10.1016/j.pbiomolbio.2012.07.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 07/16/2012] [Indexed: 02/07/2023]
Abstract
Altered mechanical loading of the heart leads to hypertrophy, decompensated heart failure and fatal arrhythmias. However, the molecular mechanisms that link mechanical and electrical dysfunction remain poorly understood. Growing evidence suggest that ventricular electrical remodeling (VER) is a process that can be induced by altered mechanical stress, creating persistent electrophysiological changes that predispose the heart to life-threatening arrhythmias. While VER is clearly a physiological property of the human heart, as evidenced by "T wave memory", it is also thought to occur in a variety of pathological states associated with altered ventricular activation such as bundle branch block, myocardial infarction, and cardiac pacing. Animal models that are currently being used for investigating stretch-induced VER have significant limitations. The zebrafish has recently emerged as an attractive animal model for studying cardiovascular disease and could overcome some of these limitations. Owing to its extensively sequenced genome, high conservation of gene function, and the comprehensive genetic resources that are available in this model, the zebrafish may provide new insights into the molecular mechanisms that drive detrimental electrical remodeling in response to stretch. Here, we have established a zebrafish model to study mechano-electrical feedback in the heart, which combines efficient genetic manipulation with high-precision stretch and high-resolution electrophysiology. In this model, only 90 min of ventricular stretch caused VER and recapitulated key features of VER found previously in the mammalian heart. Our data suggest that the zebrafish model is a powerful platform for investigating the molecular mechanisms underlying mechano-electrical feedback and VER in the heart.
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Verkerk AO, Remme CA. Zebrafish: a novel research tool for cardiac (patho)electrophysiology and ion channel disorders. Front Physiol 2012; 3:255. [PMID: 22934012 PMCID: PMC3429032 DOI: 10.3389/fphys.2012.00255] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 06/19/2012] [Indexed: 12/19/2022] Open
Abstract
The zebrafish is a cold-blooded tropical freshwater teleost with two-chamber heart morphology. A major advantage of the zebrafish for heart studies is that the embryo is transparent, allowing for easy assessment of heart development, heart rate analysis and phenotypic characterization. Moreover, rapid and effective gene-specific knockdown can be achieved using morpholino oligonucleotides. Lastly, zebrafish are small in size, are easy to maintain and house, grow fast, and have large offspring size, making them a cost-efficient research model. Zebrafish embryonic and adult heart rates as well as action potential (AP) shape and duration and electrocardiogram morphology closely resemble those of humans. However, whether the zebrafish is truly an attractive alternative model for human cardiac electrophysiology depends on the presence and gating properties of the various ion channels in the zebrafish heart, but studies into the latter are as yet limited. The rapid component of the delayed rectifier K+ current (IKr) remains the best characterized and validated ion current in zebrafish myocytes, and zebrafish may represent a valuable model to investigate human IKr channel-related disease, including long QT syndrome. Arguments against the use of zebrafish as model for human cardiac (patho)electrophysiology include its cold-bloodedness and two-chamber heart morphology, absence of t-tubuli, sarcoplamatic reticulum function, and a different profile of various depolarizing and repolarizing ion channels, including a limited Na+ current density. Based on the currently available literature, we propose that zebrafish may constitute a relevant research model for investigating ion channel disorders associated with abnormal repolarization, but may be less suitable for studying depolarization disorders or Ca2+-modulated arrhythmias.
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Affiliation(s)
- Arie O Verkerk
- Department of Anatomy, Embryology, and Physiology, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
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Kettunen P. Calcium imaging in the zebrafish. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:1039-71. [PMID: 22453983 DOI: 10.1007/978-94-007-2888-2_48] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The zebrafish (Danio rerio) has emerged as a new model system during the last three decades. The fact that the zebrafish larva is transparent enables sophisticated in vivo imaging. While being the vertebrate, the reduced complexity of its nervous system and small size make it possible to follow large-scale activity in the whole brain. Its genome is sequenced and many genetic and molecular tools have been developed that simplify the study of gene function. Since the mid 1990s, the embryonic development and neuronal function of the larval, and later, adult zebrafish have been studied using calcium imaging methods. The choice of calcium indicator depends on the desired number of cells to study and cell accessibility. Dextran indicators have been used to label cells in the developing embryo from dye injection into the one-cell stage. Dextrans have also been useful for retrograde labeling of spinal cord neurons and cells in the olfactory system. Acetoxymethyl (AM) esters permit labeling of larger areas of tissue such as the tectum, a region responsible for visual processing. Genetically encoded calcium indicators have been expressed in various tissues by the use of cell-specific promoters. These studies have contributed greatly to our understanding of basic biological principles during development and adulthood, and of the function of disease-related genes in a vertebrate system.
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Affiliation(s)
- Petronella Kettunen
- Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Sweden.
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