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Genge CE, Muralidharan P, Kemp J, Hull CM, Yip M, Simpson K, Hunter DV, Claydon TW. Zebrafish cardiac repolarization does not functionally depend on the expression of the hERG1b-like transcript. Pflugers Arch 2024; 476:87-99. [PMID: 37934265 DOI: 10.1007/s00424-023-02875-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/08/2023]
Abstract
Zebrafish provide a translational model of human cardiac function. Their similar cardiac electrophysiology enables screening of human cardiac repolarization disorders, drug arrhythmogenicity, and novel antiarrhythmic therapeutics. However, while zebrafish cardiac repolarization is driven by delayed rectifier potassium channel current (IKr), the relative role of alternate channel transcripts is uncertain. While human ether-a-go-go-related-gene-1a (hERG1a) is the dominant transcript in humans, expression of the functionally distinct alternate transcript, hERG1b, modifies the electrophysiological and pharmacologic IKr phenotype. Studies of zebrafish IKr are frequently translated without consideration for the presence and impact of hERG1b in humans. Here, we performed phylogenetic analyses of all available KCNH genes from Actinopterygii (ray-finned fishes). Our findings confirmed zebrafish cardiac zkcnh6a as the paralog of human hERG1a (hKCNH2a), but also revealed evidence of a hERG1b (hKCNH2b)-like N-terminally truncated gene, zkcnh6b, in zebrafish. zkcnh6b is a teleost-specific variant that resulted from the 3R genome duplication. qRT-PCR showed dominant expression of zkcnh6a in zebrafish atrial and ventricular tissue, with low levels of zkcnh6b. Functional evaluation of zkcnh6b in a heterologous system showed no discernable function under the conditions tested, and no influence on zkcnh6a function during the zebrafish ventricular action potential. Our findings provide the first descriptions of the zkcnh6b gene, and show that, unlike in humans, zebrafish cardiac repolarization does not rely upon co-assembly of zERG1a/zERG1b. Given that hERG1b modifies IKr function and drug binding in humans, our findings highlight the need for consideration when translating hERG variant effects and toxicological screens in zebrafish, which lack a functional hERG1b-equivalent gene.
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Affiliation(s)
- Christine E Genge
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada
| | - Padmapriya Muralidharan
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada
| | - Jake Kemp
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada
| | - Christina M Hull
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada
| | - Mandy Yip
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada
| | - Kyle Simpson
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada
| | - Diana V Hunter
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada
| | - Thomas W Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Burnaby, B.C, Canada.
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De la Cruz A, Wu X, Rainer QC, Hiniesto-Iñigo I, Perez ME, Edler I, Liin SI, Larsson HP. Pharmacological Screening of Kv7.1 and Kv7.1/KCNE1 Activators as Potential Antiarrhythmic Drugs in the Zebrafish Heart. Int J Mol Sci 2023; 24:12092. [PMID: 37569465 PMCID: PMC10418701 DOI: 10.3390/ijms241512092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
Long QT syndrome (LQTS) can lead to ventricular arrhythmia and sudden cardiac death. The most common congenital cause of LQTS is mutations in the channel subunits generating the cardiac potassium current IKs. Zebrafish (Danio rerio) have been proposed as a powerful system to model human cardiac diseases due to the similar electrical properties of the zebrafish heart and the human heart. We used high-resolution all-optical electrophysiology on ex vivo zebrafish hearts to assess the effects of IKs analogues on the cardiac action potential. We found that chromanol 293B (an IKs inhibitor) prolonged the action potential duration (APD) in the presence of E4031 (an IKr inhibitor applied to drug-induced LQT2), and to a lesser extent, in the absence of E4031. Moreover, we showed that PUFA analogues slightly shortened the APD of the zebrafish heart. However, PUFA analogues failed to reverse the APD prolongation in drug-induced LQT2. However, a more potent IKs activator, ML-277, partially reversed the APD prolongation in drug-induced LQT2 zebrafish hearts. Our results suggest that IKs plays a limited role in ventricular repolarizations in the zebrafish heart under resting conditions, although it plays a more important role when the IKr is compromised, as if the IKs in zebrafish serves as a repolarization reserve as in human hearts. This study shows that potent IKs activators can restore the action potential duration in drug-induced LQT2 in the zebrafish heart.
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Affiliation(s)
- Alicia De la Cruz
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, 1600 NW 10th Avenue, Miami, FL 33136, USA
| | - Xiaoan Wu
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, 1600 NW 10th Avenue, Miami, FL 33136, USA
| | - Quinn C. Rainer
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, 1600 NW 10th Avenue, Miami, FL 33136, USA
| | - Irene Hiniesto-Iñigo
- Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden
| | - Marta E. Perez
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, 1600 NW 10th Avenue, Miami, FL 33136, USA
| | - Isak Edler
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, 1600 NW 10th Avenue, Miami, FL 33136, USA
- Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden
| | - Sara I. Liin
- Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden
| | - H. Peter Larsson
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, 1600 NW 10th Avenue, Miami, FL 33136, USA
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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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Ling D, Chen H, Chan G, Lee SMY. Quantitative measurements of zebrafish heartrate and heart rate variability: A survey between 1990-2020. Comput Biol Med 2021; 142:105045. [PMID: 34995954 DOI: 10.1016/j.compbiomed.2021.105045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/14/2021] [Accepted: 11/14/2021] [Indexed: 12/19/2022]
Abstract
Zebrafish is an essential model organism for studying cardiovascular diseases, given its advantages of fast proliferation and high gene homology with humans. Zebrafish embryos/larvae are valuable experimental models used in toxicology studies to analyze drug toxicity, including hepatoxicity, nephrotoxicity and cardiotoxicity, as well as for drug discovery and drug safety screening in the preclinical stage. Heart rate (HR) serves as a functional endpoint in studies of cardiotoxicity, while heart rate variability (HRV) serves as an indicator of cardiac arrhythmia. Cardiotoxicity is a major cause of early and late termination of drug trials, so a more comprehensive understanding of zebrafish HR and HRV is important. This review summarized HR and HRV in a specific range of applications and fields, focusing on zebrafish heartbeat detection procedures, signal analysis technology and well-established commercial software, such as LabVIEW, Rvlpulse, and ZebraLab. We also compared HR detection algorithms and electrocardiography (ECG)-based methods of heart signal extraction. The relationship between HR and HRV was also systematically analyzed; HR was shown to have an inverse correlation with HRV. Applications to drug testing are also highlighted in this review. Furthermore, HR and HRV were shown to be regulated by the automatic nervous system; their connections with ECG measurements are also summarized herein.
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Affiliation(s)
- Dongmin Ling
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macao, China
| | - Huanxian Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macao, China
| | - Ging Chan
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macao, China; Department of Public Health and Medicinal Administration, Faculty of Health Sciences, University of Macau, Macao, China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macao, China; Department of Pharmaceutical Sciences, Faculty of Health Sciences, University of Macau, Macao, China.
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