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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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Cui S, Hayashi K, Kobayashi I, Hosomichi K, Nomura A, Teramoto R, Usuda K, Okada H, Deng Y, Kobayashi-Sun J, Nishikawa T, Furusho H, Saito T, Hirase H, Ohta K, Fujimoto M, Horita Y, Kusayama T, Tsuda T, Tada H, Kato T, Usui S, Sakata K, Fujino N, Tajima A, Yamagishi M, Takamura M. The utility of zebrafish cardiac arrhythmia model to predict the pathogenicity of KCNQ1 variants. J Mol Cell Cardiol 2023; 177:50-61. [PMID: 36898499 DOI: 10.1016/j.yjmcc.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023]
Abstract
Genetic testing for inherited arrhythmias and discriminating pathogenic or benign variants from variants of unknown significance (VUS) is essential for gene-based medicine. KCNQ1 is a causative gene of type 1 long QT syndrome (LQTS), and approximately 30% of the variants found in type 1 LQTS are classified as VUS. We studied the role of zebrafish cardiac arrhythmia model in determining the clinical significance of KCNQ1 variants. We generated homozygous kcnq1 deletion zebrafish (kcnq1del/del) using the CRISPR/Cas9 and expressed human Kv7.1/MinK channels in kcnq1del/del embryos. We dissected the hearts from the thorax at 48 h post-fertilization and measured the transmembrane potential of the ventricle in the zebrafish heart. Action potential duration was calculated as the time interval between peak maximum upstroke velocity and 90% repolarization (APD90). The APD90 of kcnq1del/del embryos was 280 ± 47 ms, which was significantly shortened by injecting KCNQ1 wild-type (WT) cRNA and KCNE1 cRNA (168 ± 26 ms, P < 0.01 vs. kcnq1del/del). A study of two pathogenic variants (S277L and T587M) and one VUS (R451Q) associated with clinically definite LQTS showed that the APD90 of kcnq1del/del embryos with these mutant Kv7.1/MinK channels was significantly longer than that of Kv7.1 WT/MinK channels. Given the functional results of the zebrafish model, R451Q could be reevaluated physiologically from VUS to likely pathogenic. In conclusion, functional analysis using in vivo zebrafish cardiac arrhythmia model can be useful for determining the pathogenicity of loss-of-function variants in patients with LQTS.
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Affiliation(s)
- Shihe Cui
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Kenshi Hayashi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan; School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
| | - Isao Kobayashi
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Kazuyoshi Hosomichi
- Laboratory of Computational Genomics, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Akihiro Nomura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Ryota Teramoto
- Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Keisuke Usuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Hirofumi Okada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Yaowen Deng
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Jingjing Kobayashi-Sun
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan; Department of Clinical Engineering, Faculty of Health Sciences, Komatsu University, Komatsu, Japan
| | - Tetsuo Nishikawa
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Hiroshi Furusho
- Department of Cardiology, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
| | - Takekatsu Saito
- Department of Pediatrics, Minamigaoka Hospital, Kanazawa, Japan
| | - Hiroaki Hirase
- Department of Cardiology, Takaoka Minami Heart Center, Takaoka, Japan
| | - Kunio Ohta
- Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Japan; Medical Education Research Center, Graduate School of Medical Sciences, Kanazawa University, Japan
| | - Manabu Fujimoto
- Department of Cardiology, Kouseiren Takaoka Hospital, Takaoka, Japan
| | - Yuki Horita
- Department of Cardiology, Kanazawa Cardiovascular Hospital, Kanazawa, Japan
| | - Takashi Kusayama
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Toyonobu Tsuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Hayato Tada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Takeshi Kato
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Soichiro Usui
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Kenji Sakata
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Noboru Fujino
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan; School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Atsushi Tajima
- Department of Bioinformatics and Genomics, Graduate School of Advanced Preventive Medical Sciences, Kanazawa University, Kanazawa, Japan
| | | | - Masayuki Takamura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
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Zhao Y, Chen C, Yun M, Issa T, Lin A, Nguyen TP. Constructing Adult Zebrafish Einthoven's Triangle to Define Electrical Heart Axes. Front Physiol 2021; 12:708938. [PMID: 34366897 PMCID: PMC8342992 DOI: 10.3389/fphys.2021.708938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/24/2021] [Indexed: 11/19/2022] Open
Abstract
Zebrafish is a popular high-throughput vertebrate model to study human cardiac electrophysiology, arrhythmias, and myopathies. One reason for this popularity is the purported striking similarities between zebrafish and human electrocardiograms (ECGs). However, zebrafish electrical heart axes were unknown. It is impossible to define heart axis based on single-lead ECG because determination of an electrical heart axis in the frontal plane requires the use of the hexaxial reference system (or Cabrera system) derived from Einthoven’s triangle. Construction of Einthoven’s triangle requires simultaneous ECG recording from at least two Einthoven bipolar leads. Therefore, we systematically constructed the first zebrafish Einthoven’s triangle by simultaneous bipolar dual-lead ECG recording to determine for the first time the three frontal electrical heart axes using the Cabrera system. Comparing zebrafish with human Einthoven’s triangle reveals that their normal frontal electrical axes were reflections of each other across 0° in the Cabrera system. The responsible mechanisms involve zebrafish vs. human cardiac activation propagating in the same direction along the heart horizontal axis but in opposite directions along the heart longitudinal axis. The same observations are true for zebrafish vs. human cardiac repolarization. This study marks a technical breakthrough in the first bipolar dual-lead ECG recording in live adult zebrafish to construct for the first time zebrafish Einthoven’s triangle. This first systematic analysis of the actual differences and similarities between normal adult zebrafish and human Einthoven’s triangles unmasked differences and similarities in the underlying cardiac axis mechanisms. Insights of the live adult zebrafish main heart axis and its three frontal electrical heart axes provide critical contextual framework to interpret the clinical relevance of the adult zebrafish heart as model for human cardiac electrophysiology.
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Affiliation(s)
- Yali Zhao
- The Cardiovascular Research Laboratory, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
| | - Connie Chen
- The Cardiovascular Research Laboratory, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
| | - Morgan Yun
- The Cardiovascular Research Laboratory, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
| | - Thomas Issa
- The Cardiovascular Research Laboratory, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
| | - Andrew Lin
- The Cardiovascular Research Laboratory, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
| | - Thao P Nguyen
- The Cardiovascular Research Laboratory, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
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Ottosson NE, Silverå Ejneby M, Wu X, Estrada-Mondragón A, Nilsson M, Karlsson U, Schupp M, Rognant S, Jepps TA, Konradsson P, Elinder F. Synthetic resin acid derivatives selectively open the hK V 7.2/7.3 channel and prevent epileptic seizures. Epilepsia 2021; 62:1744-1758. [PMID: 34085706 DOI: 10.1111/epi.16932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/19/2021] [Accepted: 05/03/2021] [Indexed: 01/10/2023]
Abstract
OBJECTIVE About one third of all patients with epilepsy have pharmacoresistant seizures. Thus there is a need for better pharmacological treatments. The human voltage-gated potassium (hKV ) channel hKV 7.2/7.3 is a validated antiseizure target for compounds that activate this channel. In a previous study we have shown that resin acid derivatives can activate the hKV 7.2/7.3 channel. In this study we investigated if these channel activators have the potential to be developed into a new type of antiseizure drug. Thus we examined their structure-activity relationships and the site of action on the hKV 7.2/7.3 channel, if they have unwanted cardiac and cardiovascular effects, and their potential antiseizure effect. METHODS Ion channels were expressed in Xenopus oocytes or mammalian cell lines and explored with two-electrode voltage-clamp or automated patch-clamp techniques. Unwanted vascular side effects were investigated with isometric tension recordings. Antiseizure activity was studied in an electrophysiological zebrafish-larvae model. RESULTS Fourteen resin acid derivatives were tested on hKV 7.2/7.3. The most efficient channel activators were halogenated and had a permanently negatively charged sulfonyl group. The compounds did not bind to the sites of other hKV 7.2/7.3 channel activators, retigabine, or ICA-069673. Instead, they interacted with the most extracellular gating charge of the S4 voltage-sensing helix, and the effects are consistent with an electrostatic mechanism. The compounds altered the voltage dependence of hKV 7.4, but in contrast to retigabine, there were no effects on the maximum conductance. Consistent with these data, the compounds had less smooth muscle-relaxing effect than retigabine. The compounds had almost no effect on the voltage dependence of hKV 11.1, hNaV 1.5, or hCaV 1.2, or on the amplitude of hKV 11.1. Finally, several resin acid derivatives had clear antiseizure effects in a zebrafish-larvae model. SIGNIFICANCE The described resin acid derivatives hold promise for new antiseizure medications, with reduced risk for adverse effects compared with retigabine.
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Affiliation(s)
- Nina E Ottosson
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Malin Silverå Ejneby
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Xiongyu Wu
- Department of Physics, Chemistry, and Biology, Linköping University, Linköping, Sweden
| | | | - Michelle Nilsson
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Urban Karlsson
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | | | - Salomé Rognant
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Andrew Jepps
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Konradsson
- Department of Physics, Chemistry, and Biology, Linköping University, Linköping, Sweden
| | - Fredrik Elinder
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
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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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Echeazarra L, Hortigón-Vinagre MP, Casis O, Gallego M. Adult and Developing Zebrafish as Suitable Models for Cardiac Electrophysiology and Pathology in Research and Industry. Front Physiol 2021; 11:607860. [PMID: 33519514 PMCID: PMC7838705 DOI: 10.3389/fphys.2020.607860] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/30/2020] [Indexed: 12/21/2022] Open
Abstract
The electrophysiological behavior of the zebrafish heart is very similar to that of the human heart. In fact, most of the genes that codify the channels and regulatory proteins required for human cardiac function have their orthologs in the zebrafish. The high fecundity, small size, and easy handling make the zebrafish embryos/larvae an interesting candidate to perform whole animal experiments within a plate, offering a reliable and low-cost alternative to replace rodents and larger mammals for the study of cardiac physiology and pathology. The employment of zebrafish embryos/larvae has widened from basic science to industry, being of particular interest for pharmacology studies, since the zebrafish embryo/larva is able to recapitulate a complete and integrated view of cardiac physiology, missed in cell culture. As in the human heart, IKr is the dominant repolarizing current and it is functional as early as 48 h post fertilization. Finally, genome editing techniques such as CRISPR/Cas9 facilitate the humanization of zebrafish embryos/larvae. These techniques allow one to replace zebrafish genes by their human orthologs, making humanized zebrafish embryos/larvae the most promising in vitro model, since it allows the recreation of human-organ-like environment, which is especially necessary in cardiac studies due to the implication of dynamic factors, electrical communication, and the paracrine signals in cardiac function.
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Affiliation(s)
- Leyre Echeazarra
- Departamento de Fisiología, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, Vitoria-Gasteiz, Spain
| | - Maria Pura Hortigón-Vinagre
- Departamento de Bioquímica y Biología Molecular y Genética>, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Oscar Casis
- Departamento de Fisiología, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, Vitoria-Gasteiz, Spain
| | - Mónica Gallego
- Departamento de Fisiología, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, Vitoria-Gasteiz, Spain
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Functional evaluation of gene mutations in Long QT Syndrome: strength of evidence from in vitro assays for deciphering variants of uncertain significance. JOURNAL OF CONGENITAL CARDIOLOGY 2020. [DOI: 10.1186/s40949-020-00037-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Genetic screening is now commonplace for patients suspected of having inherited cardiac conditions. Variants of uncertain significance (VUS) in disease-associated genes pose problems for the diagnostician and reliable methods for evaluating VUS function are required. Although function is difficult to interrogate for some genes, heritable channelopathies have established mechanisms that should be amenable to well-validated evaluation techniques.
The cellular electrophysiology techniques of ‘voltage-’ and ‘patch-’ clamp have a long history of successful use and have been central to identifying both the roles of genes involved in different forms of congenital Long QT Syndrome (LQTS) and the mechanisms by which mutations lead to aberrant ion channel function underlying clinical phenotypes. This is particularly evident for KCNQ1, KCNH2 and SCN5A, mutations in which underlie > 90% of genotyped LQTS cases (the LQT1-LQT3 subtypes). Recent studies utilizing high throughput (HT) planar patch-clamp recording have shown it to discriminate effectively between rare benign and pathological variants, studied through heterologous expression of recombinant channels. In combination with biochemical methods for evaluating channel trafficking and supported by biophysical modelling, patch clamp also provides detailed mechanistic insight into the functional consequences of identified mutations. Whilst potentially powerful, patient-specific stem-cell derived cardiomyocytes and genetically modified animal models are currently not well-suited to high throughput VUS study.
Conclusion
The widely adopted 2015 American College of Medical Genetics (ACMG) and Association for Molecular Pathology (AMP) guidelines for the interpretation of sequence variants include the PS3 criterion for consideration of evidence from well-established in vitro or in vivo assays. The wealth of information on underlying mechanisms of LQT1-LQT3 and recent HT patch clamp data support consideration of patch clamp data together (for LQT1 and LQT2) with information from biochemical trafficking assays as meeting the PS3 criterion of well established assays, able to provide ‘strong’ evidence for functional pathogenicity of identified VUS.
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Kanyo R, Wang CK, Locskai LF, Li J, Allison WT, Kurata HT. Functional and behavioral signatures of Kv7 activator drug subtypes. Epilepsia 2020; 61:1678-1690. [PMID: 32652600 DOI: 10.1111/epi.16592] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Voltage-gated potassium channels of the KCNQ (Kv7) family are targeted by a variety of activator compounds with therapeutic potential for treatment of epilepsy. Exploration of this drug class has revealed a variety of effective compounds with diverse mechanisms. In this study, we aimed to clarify functional criteria for categorization of Kv7 activator compounds, and to compare the effects of prototypical drugs in a zebrafish larvae model. METHODS In vitro electrophysiological approaches with recombinant ion channels were used to highlight functional properties important for classification of drug mechanisms. We also benchmarked the effects of representative antiepileptic Kv7 activator drugs using behavioral seizure assays of zebrafish larvae and in vivo Ca2+ imaging with the ratiometric Ca2+ sensor CaMPARI. RESULTS Drug effects on channel gating kinetics, and drug sensitivity profiles to diagnostic channel mutations, were used to highlight properties for categorization of Kv7 activator drugs into voltage sensor-targeted or pore-targeted subtypes. Quantifying seizures and ratiometric Ca2+ imaging in freely swimming zebrafish larvae demonstrated that while all Kv7 activators tested lead to suppression of neuronal excitability, pore-targeted activators (like ML213 and retigabine) strongly suppress seizure behavior, whereas ICA-069673 triggers a seizure-like hypermotile behavior. SIGNIFICANCE This study suggests criteria to categorize antiepileptic Kv7 activator drugs based on their underlying mechanism. We also establish the use of in vivo CaMPARI as a tool for screening effects of anticonvulsant drugs on neuronal excitability in zebrafish. In summary, despite a shared ability to suppress neuronal excitability, our findings illustrate how mechanistic differences between Kv7 activator subtypes influence their effects on heteromeric channels and lead to vastly different in vivo outcomes.
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Affiliation(s)
- Richard Kanyo
- Department of Biological Sciences, Centre for Prions and Protein Folding Disease, University of Alberta, Edmonton, Alberta, Canada
| | - Caroline K Wang
- Department of Pharmacology, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Laszlo F Locskai
- Department of Biological Sciences, Centre for Prions and Protein Folding Disease, University of Alberta, Edmonton, Alberta, Canada
| | - Jingru Li
- Department of Pharmacology, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - W Ted Allison
- Department of Biological Sciences, Centre for Prions and Protein Folding Disease, University of Alberta, Edmonton, Alberta, Canada
| | - Harley T Kurata
- Department of Pharmacology, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
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Gawel K, Langlois M, Martins T, van der Ent W, Tiraboschi E, Jacmin M, Crawford AD, Esguerra CV. Seizing the moment: Zebrafish epilepsy models. Neurosci Biobehav Rev 2020; 116:1-20. [PMID: 32544542 DOI: 10.1016/j.neubiorev.2020.06.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/20/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022]
Abstract
Zebrafish are now widely accepted as a valuable animal model for a number of different central nervous system (CNS) diseases. They are suitable both for elucidating the origin of these disorders and the sequence of events culminating in their onset, and for use as a high-throughput in vivo drug screening platform. The availability of powerful and effective techniques for genome manipulation allows the rapid modelling of different genetic epilepsies and of conditions with seizures as a core symptom. With this review, we seek to summarize the current knowledge about existing epilepsy/seizures models in zebrafish (both pharmacological and genetic) and compare them with equivalent rodent and human studies. New findings obtained from the zebrafish models are highlighted. We believe that this comprehensive review will highlight the value of zebrafish as a model for investigating different aspects of epilepsy and will help researchers to use these models to their full extent.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | | | - Teresa Martins
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Ettore Tiraboschi
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Neurophysics Group, Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, Building 14, 38068, Rovereto, TN, Italy
| | - Maxime Jacmin
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Alexander D Crawford
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg; Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.
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10
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Yao Q, Wang L, Mittal R, Yan D, Richmond MT, Denyer S, Requena T, Liu K, Varshney GK, Lu Z, Liu XZ. Transcriptomic Analyses of Inner Ear Sensory Epithelia in Zebrafish. Anat Rec (Hoboken) 2019; 303:527-543. [PMID: 31883312 DOI: 10.1002/ar.24331] [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] [Received: 12/07/2018] [Revised: 08/01/2019] [Accepted: 11/18/2019] [Indexed: 12/25/2022]
Abstract
Analysis of gene expression has the potential to assist in the understanding of multiple cellular processes including proliferation, cell-fate specification, senesence, and activity in both healthy and disease states. Zebrafish model has been increasingly used to understand the process of hearing and the development of the vertebrate auditory system. Within the zebrafish inner ear, there are three otolith organs, each containing a sensory macula of hair cells. The saccular macula is primarily involved in hearing, the utricular macula is primarily involved in balance and the function of the lagenar macula is not completely understood. The goal of this study is to understand the transcriptional differences in the sensory macula associated with different otolith organs with the intention of understanding the genetic mechanisms responsible for the distinct role each organ plays in sensory perception. The sensory maculae of the saccule, utricle, and lagena were dissected out of adult Et(krt4:GFP)sqet4 zebrafish expressing green fluorescent protein in hair cells for transcriptional analysis. The total RNAs of the maculae were isolated and analyzed by RNA GeneChip microarray. Several of the differentially expressed genes are known to be involved in deafness, otolith development and balance. Gene expression among these otolith organs was very well conserved with less than 10% of genes showing differential expression. Data from this study will help to elucidate which genes are involved in hearing and balance. Furthermore, the findings of this study will assist in the development of the zebrafish model for human hearing and balance disorders. Anat Rec, 303:527-543, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
- Qi Yao
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Biology, University of Miami, Miami, Florida
| | - Lingyu Wang
- Department of Biology, University of Miami, Miami, Florida
| | - Rahul Mittal
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Denise Yan
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida
| | | | - Steven Denyer
- Department of Biology, University of Miami, Miami, Florida
| | - Teresa Requena
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Kaili Liu
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Zhongmin Lu
- Department of Biology, University of Miami, Miami, Florida
| | - Xue Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, Hunan, China
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11
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Zhu XY, Xia B, Wu YY, Yang H, Li CQ, Li P. Fenobucarb induces heart failure and cerebral hemorrhage in zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 209:34-41. [PMID: 30685545 DOI: 10.1016/j.aquatox.2018.12.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/27/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
The potential risk and toxic mechanisms of fenobucarb (2-sec-butylphenyl methylcarbamate, BPMC) to animals and humans have not been fully elucidated. In this study, zebrafish embryos were exposed to various concentrations of BPMC from 48 hpf (hour post fertilization, hpf) to 72 hpf. We found that BPMC induced severe heart failure with bradycardia, reduced heart contractions, cardiac output and blood flow dynamics;and myocardial apoptosis. BPMC also induced cerebral hemorrhages and blood erythrocyte reduction in a dose-dependent manner. Also observed were increased ROS production and capase 9 and 3/7 activation. The mRNA levels of the ATPase-related gene (atp2a1l), calcium channel-related gene (cacna1ab), sodium channel-related gene (scn5Lab), potassium channel-related gene (kcnq1), the regulatory gene (tnnc1a) for cardiac troponin C, and several apoptosis-related genes were significantly downregulated in zebrafish following BPMC exposure. These results suggest that exposure to BPMC is a possible risk factor to cardiovascular and cerebrovascular systems in animals.
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Affiliation(s)
- Xiao-Yu Zhu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, PR China; Hunter Biotechnology, Inc, F1A, Building 5, No. 88 Jiangling Road, Binjiang Zone, Hangzhou City, Zhejiang Province 310051, PR China
| | - Bo Xia
- Hunter Biotechnology, Inc, F1A, Building 5, No. 88 Jiangling Road, Binjiang Zone, Hangzhou City, Zhejiang Province 310051, PR China
| | - Yu-Ying Wu
- Hunter Biotechnology, Inc, F1A, Building 5, No. 88 Jiangling Road, Binjiang Zone, Hangzhou City, Zhejiang Province 310051, PR China
| | - Hua Yang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, PR China
| | - Chun-Qi Li
- Hunter Biotechnology, Inc, F1A, Building 5, No. 88 Jiangling Road, Binjiang Zone, Hangzhou City, Zhejiang Province 310051, PR China.
| | - Ping Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, PR China.
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12
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Pickett SB, Raible DW. Water Waves to Sound Waves: Using Zebrafish to Explore Hair Cell Biology. J Assoc Res Otolaryngol 2019; 20:1-19. [PMID: 30635804 DOI: 10.1007/s10162-018-00711-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 12/19/2018] [Indexed: 01/09/2023] Open
Abstract
Although perhaps best known for their use in developmental studies, over the last couple of decades, zebrafish have become increasingly popular model organisms for investigating auditory system function and disease. Like mammals, zebrafish possess inner ear mechanosensory hair cells required for hearing, as well as superficial hair cells of the lateral line sensory system, which mediate detection of directional water flow. Complementing mammalian studies, zebrafish have been used to gain significant insights into many facets of hair cell biology, including mechanotransduction and synaptic physiology as well as mechanisms of both hereditary and acquired hair cell dysfunction. Here, we provide an overview of this literature, highlighting some of the particular advantages of using zebrafish to investigate hearing and hearing loss.
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Affiliation(s)
- Sarah B Pickett
- Department of Biological Structure, University of Washington, Health Sciences Building H-501, 1959 NE Pacific Street, Box 357420, Seattle, WA, 98195-7420, USA
- Graduate Program in Neuroscience, University of Washington, 1959 NE Pacific Street, Box 357270, Seattle, WA, 98195-7270, USA
| | - David W Raible
- Department of Biological Structure, University of Washington, Health Sciences Building H-501, 1959 NE Pacific Street, Box 357420, Seattle, WA, 98195-7420, USA.
- Graduate Program in Neuroscience, University of Washington, 1959 NE Pacific Street, Box 357270, Seattle, WA, 98195-7270, USA.
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, 1701 NE Columbia Rd, Box 357923, Seattle, WA, 98195-7923, USA.
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13
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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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14
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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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15
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Abramochkin DV, Hassinen M, Vornanen M. Transcripts of Kv7.1 and MinK channels and slow delayed rectifier K + current (I Ks) are expressed in zebrafish (Danio rerio) heart. Pflugers Arch 2018; 470:1753-1764. [PMID: 30116893 DOI: 10.1007/s00424-018-2193-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/24/2018] [Accepted: 08/06/2018] [Indexed: 12/18/2022]
Abstract
Zebrafish are increasingly used as a model for human cardiac electrophysiology, arrhythmias, and drug screening. However, K+ ion channels of the zebrafish heart, which determine the rate of repolarization and duration of cardiac action potential (AP) are still incompletely known and characterized. Here, we provide the first evidence for the presence of the slow component of the delayed rectifier K+channels in the zebrafish heart and characterize electrophysiological properties of the slow component of the delayed rectifier K+current, IKs. Zebrafish atrium and ventricle showed strong transcript expression of the kcnq1 gene, which encodes the Kv7.1 α-subunit of the slow delayed rectifier K+ channel. In contrast, the kcne1 gene, encoding the MinK β-subunit of the delayed rectifier, was expressed at 21 and 17 times lower level in ventricle and atrium, respectively, in comparison to the kcnq1. IKs was observed in 62% of ventricular myocytes with mean (± SEM) density of 1.23 ± 0.37 pA/pF at + 30 mV. Activation rate of IKs was 38% faster (τ50 = 1248 ± 215 ms) than kcnq1:kcne1 channels (1725 ± 792 ms) expressed in 3:1 ratio in Chinese hamster ovary cells. Microelectrode experiments demonstrated the functional relevance of IKs in the zebrafish heart, since 100 μM chromanol 293B produced a significant prolongation of AP in zebrafish ventricle. We conclude that AP repolarization in zebrafish ventricle is contributed by IKs, which is mainly generated by homotetrameric Kv7.1 channels not coupled to MinK ancillary β-subunits. This is a clear difference to the human heart, where MinK is an essential component of the slow delayed rectifier K+channel.
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Affiliation(s)
- Denis V Abramochkin
- Department of Human and Animal Physiology, Biological faculty, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia.
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russia.
- Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.
| | - Minna Hassinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
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16
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Bouzid A, Smeti I, Dhouib L, Roche M, Achour I, Khalfallah A, Gibriel AA, Charfeddine I, Ayadi H, Lachuer J, Ghorbel A, Petit C, Masmoudi S. Down-expression of P2RX2, KCNQ5, ERBB3 and SOCS3 through DNA hypermethylation in elderly women with presbycusis. Biomarkers 2018; 23:347-356. [PMID: 29325454 DOI: 10.1080/1354750x.2018.1427795] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CONTEXT Presbycusis, an age-related hearing impairment (ARHI), represents the most common sensory disability in adults. Today, the molecular mechanisms underlying presbycusis remain unclear. This is in particular due to the fact that ARHI is a multifactorial complex disorder resulting from several genomic factors interacting with lifelong cumulative effects of: disease, diet, and environment. OBJECTIVE Identification of novel biomarkers for presbycusis. MATERIALS AND METHODS We selectively ascertained 18 elderly unrelated women lacking environmental and metabolic risk factors. Subsequently, we screened for methylation map changes in blood samples of women with presbycusis as compared to controls, using reduced representation bisulfite sequencing. We focused on hypermethylated cytosine bases located in gene promoters and the first two exons. To elucidate the related gene expression changes, we performed transcriptomic study using gene expression microarray. RESULTS Twenty-seven genes, known to be expressed in adult human cochlea, were found in the blood cells to be differentially hypermethylated with significant (p < 0.01) methylation differences (>30%) and down-expressed with fold change >1.2 (FDR <0.05). Functional annotation and qRT-PCR further identified P2RX2, KCNQ5, ERBB3 and SOCS3 to be associated with the progression of ARHI. DISCUSSION AND CONCLUSION Down-expressed genes associated with DNA hypermethylation could be used as biomarkers for understanding complex pathogenic mechanisms underlying presbycusis.
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Affiliation(s)
- Amal Bouzid
- a Laboratoire de Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax , Université de Sfax , Sfax , Tunisie
| | - Ibtihel Smeti
- a Laboratoire de Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax , Université de Sfax , Sfax , Tunisie
| | - Leila Dhouib
- b Service d'O.R.L, C.H.U. H. Bourguiba de Sfax , Sfax , Tunisie
| | - Magali Roche
- c Faculté de Médecine et de Pharmacie de Lyon, ISPBL, ProfileXpert-LCM , Lyon , France
| | - Imen Achour
- b Service d'O.R.L, C.H.U. H. Bourguiba de Sfax , Sfax , Tunisie
| | - Aida Khalfallah
- a Laboratoire de Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax , Université de Sfax , Sfax , Tunisie
| | - Abdullah Ahmed Gibriel
- d Department of Biochemistry and Molecular Biology, Faculty of Pharmacy , The British University in Egypt , Cairo , Egypt
| | | | - Hammadi Ayadi
- a Laboratoire de Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax , Université de Sfax , Sfax , Tunisie
| | - Joel Lachuer
- c Faculté de Médecine et de Pharmacie de Lyon, ISPBL, ProfileXpert-LCM , Lyon , France
| | | | - Christine Petit
- e Unité de Génétique et Physiologie de l'Audition , Institut Pasteur , Paris , France.,f UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM) , Paris , France.,g Collège de France , Paris , France
| | - Saber Masmoudi
- a Laboratoire de Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax , Université de Sfax , Sfax , Tunisie
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17
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Coordinated Expression of Two Types of Low-Threshold K + Channels Establishes Unique Single Spiking of Mauthner Cells among Segmentally Homologous Neurons in the Zebrafish Hindbrain. eNeuro 2017; 4:eN-NWR-0249-17. [PMID: 29085904 PMCID: PMC5659376 DOI: 10.1523/eneuro.0249-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 01/15/2023] Open
Abstract
Expression of different ion channels permits homologously-generated neurons to acquire different types of excitability and thus code various kinds of input information. Mauthner (M) series neurons in the teleost hindbrain consist of M cells and their morphological homologs, which are repeated in adjacent segments and share auditory inputs. When excited, M cells generate a single spike at the onset of abrupt stimuli, while their homologs encode input intensity with firing frequency. Our previous study in zebrafish showed that immature M cells burst phasically at 2 d postfertilization (dpf) and acquire single spiking at 4 dpf by specific expression of auxiliary Kvβ2 subunits in M cells in association with common expression of Kv1.1 channels in the M series. Here, we further reveal the ionic mechanisms underlying this functional differentiation. Pharmacological blocking of Kv7/KCNQ in addition to Kv1 altered mature M cells to fire tonically, similar to the homologs. In contrast, blocking either channel alone caused M cells to burst phasically. M cells at 2 dpf fired tonically after blocking Kv7. In situ hybridization revealed specific Kv7.4/KCNQ4 expression in M cells at 2 dpf. Kv7.4 and Kv1.1 channels expressed in Xenopus oocytes exhibited low-threshold outward currents with slow and fast rise times, while coexpression of Kvβ2 accelerated and increased Kv1.1 currents, respectively. Computational models, modified from a mouse cochlear neuron model, demonstrated that Kv7.4 channels suppress repetitive firing to produce spike-frequency adaptation, while Kvβ2-associated Kv1.1 channels increase firing threshold and decrease the onset latency of spiking. Altogether, coordinated expression of these low-threshold K+ channels with Kvβ2 functionally differentiates M cells among homologous neurons.
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18
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Vornanen M. Electrical Excitability of the Fish Heart and Its Autonomic Regulation. FISH PHYSIOLOGY 2017. [DOI: 10.1016/bs.fp.2017.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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19
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Wilcox A, Willis CKR. Energetic benefits of enhanced summer roosting habitat for little brown bats (Myotis lucifugus) recovering from white-nose syndrome. CONSERVATION PHYSIOLOGY 2016; 4:cov070. [PMID: 27293749 PMCID: PMC4771111 DOI: 10.1093/conphys/cov070] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 12/01/2015] [Accepted: 12/12/2015] [Indexed: 06/01/2023]
Abstract
Habitat modification can improve outcomes for imperilled wildlife. Insectivorous bats in North America face a range of conservation threats, including habitat loss and white-nose syndrome (WNS). Even healthy bats face energetic constraints during spring, but enhancement of roosting habitat could reduce energetic costs, increase survival and enhance recovery from WNS. We tested the potential of artificial heating of bat roosts as a management tool for threatened bat populations. We predicted that: (i) after hibernation, captive bats would be more likely to select a roost maintained at a temperature near their thermoneutral zone; (ii) bats recovering from WNS at the end of hibernation would show a stronger preference for heated roosts compared with healthy bats; and (iii) heated roosts would result in biologically significant energy savings. We housed two groups of bats (WNS-positive and control) in separate flight cages following hibernation. Over 7.5 weeks, we quantified the presence of individuals in heated vs. unheated bat houses within each cage. We then used a series of bioenergetic models to quantify thermoregulatory costs in each type of roost under a number of scenarios. Bats preferentially selected heated bat houses, but WNS-affected bats were much more likely to use the heated bat house compared with control animals. Our model predicted energy savings of up to 81.2% for bats in artificially heated roosts if roost temperature was allowed to cool at night to facilitate short bouts of torpor. Our results are consistent with research highlighting the importance of roost microclimate and suggest that protection and enhancement of high-quality, natural roosting environments should be a priority response to a range of threats, including WNS. Our findings also suggest the potential of artificially heated bat houses to help populations recover from WNS, but more work is needed before these might be implemented on a large scale.
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Affiliation(s)
| | - Craig K. R. Willis
- Corresponding author: Department of Biology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB, Canada R3B 2E9. Tel: +1 204 786 9433.
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20
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Hedegaard ER, Johnsen J, Povlsen JA, Jespersen NR, Shanmuganathan JA, Laursen MR, Kristiansen SB, Simonsen U, Botker HE. Inhibition of KV7 Channels Protects the Rat Heart against Myocardial Ischemia and Reperfusion Injury. ACTA ACUST UNITED AC 2016; 357:94-102. [DOI: 10.1124/jpet.115.230409] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/05/2016] [Indexed: 02/06/2023]
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21
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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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22
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Testai L, Barrese V, Soldovieri MV, Ambrosino P, Martelli A, Vinciguerra I, Miceli F, Greenwood IA, Curtis MJ, Breschi MC, Sisalli MJ, Scorziello A, Canduela MJ, Grandes P, Calderone V, Taglialatela M. Expression and function of Kv7.4 channels in rat cardiac mitochondria: possible targets for cardioprotection. Cardiovasc Res 2015; 110:40-50. [PMID: 26718475 DOI: 10.1093/cvr/cvv281] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 12/22/2015] [Indexed: 02/06/2023] Open
Abstract
AIMS Plasmalemmal Kv7.1 (KCNQ1) channels are critical players in cardiac excitability; however, little is known on the functional role of additional Kv7 family members (Kv7.2-5) in cardiac cells. In this work, the expression, function, cellular and subcellular localization, and potential cardioprotective role against anoxic-ischaemic cardiac injury of Kv7.4 channels have been investigated. METHODS AND RESULTS Expression of Kv7.1 and Kv7.4 transcripts was found in rat heart tissue by quantitative polymerase chain reaction. Western blots detected Kv7.4 subunits in mitochondria from Kv7.4-transfected cells, H9c2 cardiomyoblasts, freshly isolated adult cardiomyocytes, and whole hearts. Immunofluorescence experiments revealed that Kv7.4 subunits co-localized with mitochondrial markers in cardiac cells, with ∼ 30-40% of cardiac mitochondria being labelled by Kv7.4 antibodies, a result also confirmed by immunogold electron microscopy experiments. In isolated cardiac (but not liver) mitochondria, retigabine (1-30 µM) and flupirtine (30 µM), two selective Kv7 activators, increased Tl(+) influx, depolarized the membrane potential, and inhibited calcium uptake; all these effects were antagonized by the Kv7 blocker XE991. In intact H9c2 cells, reducing Kv7.4 expression by RNA interference blunted retigabine-induced mitochondrial membrane depolarization; in these cells, retigabine decreased mitochondrial Ca(2+) levels and increased radical oxygen species production, both effects prevented by XE991. Finally, retigabine reduced cellular damage in H9c2 cells exposed to anoxia/re-oxygenation and largely prevented the functional and morphological changes triggered by global ischaemia/reperfusion (I/R) in Langendorff-perfused rat hearts. CONCLUSION Kv7.4 channels are present and functional in cardiac mitochondria; their activation exerts a significant cardioprotective role, making them potential therapeutic targets against I/R-induced cardiac injury.
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Affiliation(s)
- Lara Testai
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Vincenzo Barrese
- Department of Neuroscience, Division of Pharmacology, University of Naples 'Federico II', Naples, Italy Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St George's University of London, London, UK
| | - Maria Virginia Soldovieri
- Department of Medicine and Health Science "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - Paolo Ambrosino
- Department of Medicine and Health Science "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - Alma Martelli
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Iolanda Vinciguerra
- Department of Medicine and Health Science "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - Francesco Miceli
- Department of Neuroscience, Division of Pharmacology, University of Naples 'Federico II', Naples, Italy
| | - Iain Andrew Greenwood
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St George's University of London, London, UK
| | - Michael John Curtis
- Cardiovascular Division, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | | | - Maria Josè Sisalli
- Department of Neuroscience, Division of Pharmacology, University of Naples 'Federico II', Naples, Italy
| | - Antonella Scorziello
- Department of Neuroscience, Division of Pharmacology, University of Naples 'Federico II', Naples, Italy
| | | | - Pedro Grandes
- Department of Neurosciences, University of the Basque Country UPV/EHU, Leioa, Spain
| | | | - Maurizio Taglialatela
- Department of Neuroscience, Division of Pharmacology, University of Naples 'Federico II', Naples, Italy Department of Medicine and Health Science "Vincenzo Tiberio", University of Molise, Campobasso, Italy
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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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Sumbre G, de Polavieja GG. The world according to zebrafish: how neural circuits generate behavior. Front Neural Circuits 2014; 8:91. [PMID: 25126059 PMCID: PMC4115616 DOI: 10.3389/fncir.2014.00091] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/11/2014] [Indexed: 11/17/2022] Open
Affiliation(s)
- Germán Sumbre
- Ecole Normale Supérieure, Institut de Biologie de l'ENS Paris, France ; Inserm, U1024 Paris, France ; CNRS, UMR 8197 Paris, France
| | - Gonzalo G de Polavieja
- Instituto Cajal, Consejo Superior de Investigaciones Científicas Madrid, Spain ; Champalimaud Neuroscience Programme, Champalimaud Center for the Unknown Lisbon, Portugal
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