1
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Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
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Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
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2
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Abbott GW. Kv Channel Ancillary Subunits: Where Do We Go from Here? Physiology (Bethesda) 2022; 37:0. [PMID: 35797055 PMCID: PMC9394777 DOI: 10.1152/physiol.00005.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 01/10/2023] Open
Abstract
Voltage-gated potassium (Kv) channels each comprise four pore-forming α-subunits that orchestrate essential duties such as voltage sensing and K+ selectivity and conductance. In vivo, however, Kv channels also incorporate regulatory subunits-some Kv channel specific, others more general modifiers of protein folding, trafficking, and function. Understanding all the above is essential for a complete picture of the role of Kv channels in physiology and disease.
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Affiliation(s)
- Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
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3
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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4
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Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry. Sci Rep 2021; 11:10719. [PMID: 34021177 PMCID: PMC8140153 DOI: 10.1038/s41598-021-90002-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 04/15/2021] [Indexed: 11/08/2022] Open
Abstract
Voltage-gated potassium (Kv) channels are a family of membrane proteins that facilitate K+ ion diffusion across the plasma membrane, regulating both resting and action potentials. Kv channels comprise four pore-forming α subunits, each with a voltage sensing domain, and they are regulated by interaction with β subunits such as those belonging to the KCNE family. Here we conducted a comprehensive biophysical characterization of stoichiometry and protein diffusion across the plasma membrane of the epithelial KCNQ1-KCNE2 complex, combining total internal reflection fluorescence (TIRF) microscopy and a series of complementary Fluorescence Fluctuation Spectroscopy (FFS) techniques. Using this approach, we found that KCNQ1-KCNE2 has a predominant 4:4 stoichiometry, while non-bound KCNE2 subunits are mostly present as dimers in the plasma membrane. At the same time, we identified unique spatio-temporal diffusion modalities and nano-environment organization for each channel subunit. These findings improve our understanding of KCNQ1-KCNE2 channel function and suggest strategies for elucidating the subunit stoichiometry and forces directing localization and diffusion of ion channel complexes in general.
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5
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Deckelbaum RA, Lobov IB, Cheung E, Halasz G, Rajamani S, Lerner J, Tong C, Li Z, Boland P, Dominguez M, Hughes V, Yancopoulos GD, Murphy AJ, Thurston G, Cao J, Romano C, Gale NW. The potassium channel Kcne3 is a VEGFA-inducible gene selectively expressed by vascular endothelial tip cells. Angiogenesis 2019; 23:179-192. [PMID: 31754927 PMCID: PMC7160073 DOI: 10.1007/s10456-019-09696-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/02/2019] [Indexed: 12/22/2022]
Abstract
Angiogenesis is largely driven by motile endothelial tip-cells capable of invading avascular tissue domains and enabling new vessel formation. Highly responsive to Vascular Endothelial Growth-Factor-A (VEGFA), endothelial tip-cells also suppress angiogenic sprouting in adjacent stalk cells, and thus have been a primary therapeutic focus in addressing neovascular pathologies. Surprisingly, however, there remains a paucity of specific endothelial tip-cell markers. Here, we employ transcriptional profiling and a lacZ reporter allele to identify Kcne3 as an early and selective endothelial tip-cell marker in multiple angiogenic contexts. In development, Kcne3 expression initiates during early phases of angiogenesis (E9) and remains specific to endothelial tip-cells, often adjacent to regions expressing VEGFA. Consistently, Kcne3 activation is highly responsive to exogenous VEGFA but maintains tip-cell specificity throughout normal retinal angiogenesis. We also demonstrate endothelial tip-cell selectivity of Kcne3 in several injury and tumor models. Together, our data show that Kcne3 is a unique marker of sprouting angiogenic tip-cells and offers new opportunities for investigating and targeting this cell type.
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Affiliation(s)
- Ron A Deckelbaum
- Department of Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA.
| | | | - Eunice Cheung
- Department of Ophthalmology, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Gabor Halasz
- Department of Bioinformatics, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Saathyaki Rajamani
- Department of Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Julia Lerner
- Department of Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Chunxiang Tong
- Department of Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Zhe Li
- Department of Oncology & Angiogenesis, Regeneron Pharmaceuticals Inc., Tarrytown, NY, 10591, USA
| | - Patricia Boland
- Department of Oncology & Angiogenesis, Regeneron Pharmaceuticals Inc., Tarrytown, NY, 10591, USA
| | - Melissa Dominguez
- Department of Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Virginia Hughes
- Department of Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - George D Yancopoulos
- Department of Research, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Andrew J Murphy
- Department of Research, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Gavin Thurston
- Department of Oncology & Angiogenesis, Regeneron Pharmaceuticals Inc., Tarrytown, NY, 10591, USA
| | - Jingtai Cao
- Department of Ophthalmology, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Carmelo Romano
- Department of Ophthalmology, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
| | - Nicholas W Gale
- Department of Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals Inc, Tarrytown, NY, 10591, USA
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6
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David JP, Lisewski U, Crump SM, Jepps TA, Bocksteins E, Wilck N, Lossie J, Roepke TK, Schmitt N, Abbott GW. Deletion in mice of X-linked, Brugada syndrome- and atrial fibrillation-associated Kcne5 augments ventricular K V currents and predisposes to ventricular arrhythmia. FASEB J 2018; 33:2537-2552. [PMID: 30289750 DOI: 10.1096/fj.201800502r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
KCNE5 is an X-linked gene encoding KCNE5, an ancillary subunit to voltage-gated potassium (KV) channels. Human KCNE5 mutations are associated with atrial fibrillation (AF)- and Brugada syndrome (BrS)-induced cardiac arrhythmias that can arise from increased potassium current in cardiomyocytes. Seeking to establish underlying molecular mechanisms, we created and studied Kcne5 knockout ( Kcne5-/0) mice. Intracardiac ECG revealed that Kcne5 deletion caused ventricular premature beats, increased susceptibility to induction of polymorphic ventricular tachycardia (60 vs. 24% in Kcne5+/0 mice), and 10% shorter ventricular refractory period. Kcne5 deletion increased mean ventricular myocyte KV current density in the apex and also in the subpopulation of septal myocytes that lack fast transient outward current ( Ito,f). The current increases arose from an apex-specific increase in slow transient outward current-1 ( IKslow,1) (conducted by KV1.5) and Ito,f (conducted by KV4) and an increase in IKslow,2 (conducted by KV2.1) in both apex and septum. Kcne5 protein localized to the intercalated discs in ventricular myocytes, where KV2.1 was also detected in both Kcne5-/0 and Kcne5+/0 mice. In HL-1 cardiac cells and human embryonic kidney cells, KCNE5 and KV2.1 colocalized at the cell surface, but predominantly in intracellular vesicles, suggesting that Kcne5 deletion increases IK,slow2 by reducing KV2.1 intracellular sequestration. The human AF-associated mutation KCNE5-L65F negative shifted the voltage dependence of KV2.1-KCNE5 channels, increasing their maximum current density >2-fold, whereas BrS-associated KCNE5 mutations produced more subtle negative shifts in KV2.1 voltage dependence. The findings represent the first reported native role for Kcne5 and the first demonstrated Kcne regulation of KV2.1 in mouse heart. Increased KV current is a manifestation of KCNE5 disruption that is most likely common to both mouse and human hearts, providing a plausible mechanistic basis for human KCNE5-linked AF and BrS.-David, J.-P., Lisewski, U., Crump, S. M., Jepps, T. A., Bocksteins, E., Wilck, N., Lossie, J., Roepke, T. K., Schmitt, N., Abbott, G. W. Deletion in mice of X-linked, Brugada syndrome- and atrial fibrillation-associated Kcne5 augments ventricular KV currents and predisposes to ventricular arrhythmia.
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Affiliation(s)
- Jens-Peter David
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ulrike Lisewski
- Medical Clinic and Polyclinic for Cardiology and Angiology, Charité Medical University of Berlin, Berlin, Germany.,Experimental and Clinical Research Center (ECRC), Charité Medical University of Berlin, Berlin, Germany
| | - Shawn M Crump
- Bioelectricity Laboratory, Department of Physiology and Biophysics, University of California, Irvine, Irvine, California, USA; and
| | - Thomas A Jepps
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elke Bocksteins
- Laboratory for Molecular Biophysics, Physiology, and Pharmacology, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Nicola Wilck
- Medical Clinic and Polyclinic for Cardiology and Angiology, Charité Medical University of Berlin, Berlin, Germany.,Experimental and Clinical Research Center (ECRC), Charité Medical University of Berlin, Berlin, Germany
| | - Janine Lossie
- Medical Clinic and Polyclinic for Cardiology and Angiology, Charité Medical University of Berlin, Berlin, Germany.,Experimental and Clinical Research Center (ECRC), Charité Medical University of Berlin, Berlin, Germany
| | - Torsten K Roepke
- Medical Clinic and Polyclinic for Cardiology and Angiology, Charité Medical University of Berlin, Berlin, Germany.,Experimental and Clinical Research Center (ECRC), Charité Medical University of Berlin, Berlin, Germany
| | - Nicole Schmitt
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, University of California, Irvine, Irvine, California, USA; and
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7
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Kcne4 deletion sex-specifically predisposes to cardiac arrhythmia via testosterone-dependent impairment of RISK/SAFE pathway induction in aged mice. Sci Rep 2018; 8:8258. [PMID: 29844497 PMCID: PMC5974354 DOI: 10.1038/s41598-018-26599-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/15/2018] [Indexed: 02/05/2023] Open
Abstract
Sudden cardiac death (SCD) is associated with both electrical and ischemic substrates, and is a major cause of ischemic heart disease mortality worldwide. Male sex predisposes to SCD but the underlying mechanisms are incompletely understood. KCNE4, a cardiac arrhythmia-associated potassium channel β-subunit, is upregulated by 5α-dihydrotestosterone (DHT). Thus, ventricular Kcne4 expression is low in young adult female mice, but high in males and postmenopausal (12+ months) females. Despite causing a sex-independent electrical substrate at 13 months of age (22% QT prolongation in both males and females; P < 0.01), Kcne4 deletion preferentially predisposed aged male mice to ischemia/reperfusion (IR)-provoked ventricular tachyarrhythmias. Interestingly, Kcne4 deletion caused baseline induction of cardioprotective RISK and SAFE pathways in 13-m-old female, but not male, mice. IR-invoked RISK/SAFE induction was also deficient in male but not female Kcne4-/- mice. Pharmacological inhibition of RISK/SAFE pathways in Kcne4-/- females eliminated sex-specific differences in IR-invoked tachyarrhythmia predisposition. Furthermore, castration of Kcne4-/- males eliminated sex-specific differences in both baseline and post-IR RISK/SAFE pathway induction, and tachyarrhythmia predisposition. Our results demonstrate for the first time that male sex can predispose in aged mice to dangerous ventricular tachyarrhythmias despite sex-independent electrical and ischemic substrates, because of testosterone-dependent impairment of RISK/SAFE pathway induction.
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8
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Hu Z, Chen M, Zhang P, Liu J, Abbott GW. Remote ischemic preconditioning differentially attenuates post-ischemic cardiac arrhythmia in streptozotocin-induced diabetic versus nondiabetic rats. Cardiovasc Diabetol 2017; 16:57. [PMID: 28446231 PMCID: PMC5406986 DOI: 10.1186/s12933-017-0537-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/19/2017] [Indexed: 02/05/2023] Open
Abstract
Background Sudden cardiac death (SCD), a leading cause of global mortality, most commonly arises from a substrate of cardiac ischemia, but requires an additional trigger. Diabetes mellitus (DM) predisposes to SCD even after adjusting for other DM-linked cardiovascular pathology such as coronary artery disease. We previously showed that remote liver ischemia preconditioning (RLIPC) is highly protective against cardiac ischemia reperfusion injury (IRI) linked ventricular arrhythmias and myocardial infarction, via induction of the cardioprotective RISK pathway, and specifically, inhibitory phosphorylation of GSK-3β (Ser 9). Methods We evaluated the impact of acute streptozotocin-induced DM on coronary artery ligation IRI-linked ventricular arrhythmogenesis and RLIPC therapy in rats. Results Post-IRI arrhythmia induction was similar in nondiabetic and DM rats, but, unexpectedly, DM rats exhibited lower incidence of SCD during reperfusion (41 vs. 100%), suggesting uncontrolled hyperglycemia does not acutely predispose to SCD. RLIPC was highly effective in both nondiabetic and DM rats at reducing incidence and duration of, and increasing latency to, all classes of ventricular tachyarrhythmias. In contrast, atrioventricular block (AVB) was highly responsive to RLIPC in nondiabetic rats (incidence reduced from 72 to 18%) but unresponsive in DM rats. RISK pathway induction was similar in nondiabetic and DM rats, thus not explaining the DM-specific resistance of AVB to therapy. Conclusions Our findings uncover important acute DM-specific differences in responsiveness to remote preconditioning for ventricular tachyarrhythmias versus AVB, which may have clinical significance given that AVB is a malignant arrhythmia twofold more common in human diabetics than nondiabetics, and correlated to plasma glucose levels >10 mmol/L.
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Affiliation(s)
- Zhaoyang Hu
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Mou Chen
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Ping Zhang
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jin Liu
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Dept. of Pharmacology and Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA.
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9
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King EC, Patel V, Anand M, Zhao X, Crump SM, Hu Z, Weisleder N, Abbott GW. Targeted deletion of Kcne3 impairs skeletal muscle function in mice. FASEB J 2017; 31:2937-2947. [PMID: 28356343 DOI: 10.1096/fj.201600965rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 03/13/2017] [Indexed: 11/11/2022]
Abstract
KCNE3 (MiRP2) forms heteromeric voltage-gated K+ channels with the skeletal muscle-expressed KCNC4 (Kv3.4) α subunit. KCNE3 was the first reported skeletal muscle K+ channel disease gene, but the requirement for KCNE3 in skeletal muscle has been questioned. Here, we confirmed KCNE3 transcript and protein expression in mouse skeletal muscle using Kcne3-/- tissue as a negative control. Whole-transcript microarray analysis (770,317 probes, interrogating 28,853 transcripts) findings were consistent with Kcne3 deletion increasing gastrocnemius oxidative metabolic gene expression and the proportion of type IIa fast-twitch oxidative muscle fibers, which was verified using immunofluorescence. The down-regulated transcript set overlapped with muscle unloading gene expression profiles (≥1.5-fold change; P < 0.05). Gastrocnemius K+ channel α subunit remodeling arising from Kcne3 deletion was highly specific, involving just 3 of 69 α subunit genes probed: known KCNE3 partners KCNC4 and KCNH2 (mERG) were down-regulated, and KCNK4 (TRAAK) was up-regulated (P < 0.05). Functionally, Kcne3-/- mice exhibited abnormal hind-limb clasping upon tail suspension (63% of Kcne3-/- mice ≥10-mo-old vs. 0% age-matched Kcne3+/+ littermates). Whereas 5 of 5 Kcne3+/+ mice exhibited the typical biphasic decline in contractile force with repetitive stimuli of hind-limb muscle, both in vivo and in vitro, this was absent in 6 of 6 Kcne3-/- mice tested. Finally, myoblasts isolated from Kcne3-/- mice exhibit faster-inactivating and smaller sustained outward currents than those from Kcne3+/+ mice. Thus, Kcne3 deletion impairs skeletal muscle function in mice.-King, E. C., Patel, V., Anand, M., Zhao, X., Crump, S. M., Hu, Z., Weisleder, N., Abbott, G. W. Targeted deletion of Kcne3 impairs skeletal muscle function in mice.
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Affiliation(s)
- Elizabeth C King
- Department of Pharmacology, Weill Medical College of Cornell University, New York, New York, USA
| | - Vishal Patel
- Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Marie Anand
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, USA.,Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | - Xiaoli Zhao
- Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Shawn M Crump
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, USA.,Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | - Zhaoyang Hu
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, USA.,Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | - Noah Weisleder
- Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA;
| | - Geoffrey W Abbott
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, USA; .,Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
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10
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Yang S, Abbott GW, Gao WD, Liu J, Luo C, Hu Z. Involvement of glycogen synthase kinase-3β in liver ischemic conditioning induced cardioprotection against myocardial ischemia and reperfusion injury in rats. J Appl Physiol (1985) 2017; 122:1095-1105. [PMID: 28153944 PMCID: PMC5451530 DOI: 10.1152/japplphysiol.00862.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/23/2017] [Accepted: 01/27/2017] [Indexed: 02/05/2023] Open
Abstract
Remote ischemic conditioning has been convincingly shown to render the myocardium resistant to a subsequent more severe sustained episode of ischemia. Compared with other organs, little is known regarding the effect of transient liver ischemic conditioning. We proposed the existence of cardioprotection induced by remote liver conditioning. Male Sprague-Dawley rats were divided into sham-operated control (no further hepatic intervention) and remote liver ischemic conditioning groups. For liver ischemic conditioning, three cycles of 5 min of liver ischemia-reperfusion stimuli were conducted before-(liver preconditioning), post-myocardial ischemia (liver postconditioning), or in combination of both (liver preconditioning + liver postconditioning). Rats were exposed to 45 min of left anterior descending coronary artery occlusion, followed by 3 h of reperfusion thereafter. ECG and hemodynamics were measured throughout the experiment. The coronary artery was reoccluded at the end of reperfusion for infarct size determination. Blood samples were taken for serum lactate dehydrogenase and creatine kinase-MB test. Heart tissues were taken for apoptosis measurements and Western blotting. Our data demonstrate that liver ischemic preconditioning, postconditioning, or a combination of both, offered strong cardioprotection, as evidenced by reduction in infarct size and cardiac tissue damage, recovery of cardiac function, and inhibition of apoptosis after ischemia-reperfusion. Moreover, liver ischemic conditioning increased cardiac (not hepatic) glycogen synthase kinase-3β (GSK-3β) phosphorylation. Accordingly, inhibition of GSK-3β mimicked the cardioprotective action of liver conditioning. These results demonstrate that remote liver ischemic conditioning protected the heart against ischemia and reperfusion injury via GSK-3β-dependent cell-survival signaling pathway.NEW & NOTEWORTHY Remote ischemic conditioning protects hearts against ischemia and reperfusion (I/R) injury. However, it is unclear whether ischemic conditioning of visceral organs such as the liver, the largest metabolic organ in the body, can produce cardioprotection. This is the first study to show the cardioprotective effect of remote liver ischemic conditioning in a rat model of myocardial I/R injury. We also, for the first time, demonstrated these protective properties are associated with glycogen synthase kinase-3β-dependent cell-survival signaling pathway.
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Affiliation(s)
- Shuai Yang
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Pharmacology, and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
| | - Wei Dong Gao
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Jin Liu
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Chaozhi Luo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zhaoyang Hu
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China;
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Regulation of human cardiac potassium channels by full-length KCNE3 and KCNE4. Sci Rep 2016; 6:38412. [PMID: 27922120 PMCID: PMC5138848 DOI: 10.1038/srep38412] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 11/09/2016] [Indexed: 12/23/2022] Open
Abstract
Voltage-gated potassium (Kv) channels comprise pore-forming α subunits and a multiplicity of regulatory proteins, including the cardiac-expressed and cardiac arrhythmia-linked transmembrane KCNE subunits. After recently uncovering novel, N-terminally extended (L) KCNE3 and KCNE4 isoforms and detecting their transcripts in human atrium, reported here are their functional effects on human cardiac Kv channel α subunits expressed in Xenopus laevis oocytes. As previously reported for short isoforms KCNE3S and KCNE4S, KCNE3L inhibited hERG; KCNE4L inhibited Kv1.1; neither form regulated the HCN1 pacemaker channel. Unlike KCNE4S, KCNE4L was a potent inhibitor of Kv4.2 and Kv4.3; co-expression of cytosolic β subunit KChIP2, which regulates Kv4 channels in cardiac myocytes, partially relieved Kv4.3 but not Kv4.2 inhibition. Inhibition of Kv4.2 and Kv4.3 by KCNE3L was weaker, and its inhibition of Kv4.2 abolished by KChIP2. KCNE3L and KCNE4L also exhibited subunit-specific effects on Kv4 channel complex inactivation kinetics, voltage dependence and recovery. Further supporting the potential physiological significance of the robust functional effects of KCNE4L on Kv4 channels, KCNE4L protein was detected in human atrium, where it co-localized with Kv4.3. The findings establish functional effects of novel human cardiac-expressed KCNE isoforms and further contribute to our understanding of the potential mechanisms influencing cardiomyocyte repolarization.
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12
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Hu Z, Hu S, Yang S, Chen M, Zhang P, Liu J, Abbott GW. Remote Liver Ischemic Preconditioning Protects against Sudden Cardiac Death via an ERK/GSK-3β-Dependent Mechanism. PLoS One 2016; 11:e0165123. [PMID: 27768739 PMCID: PMC5074543 DOI: 10.1371/journal.pone.0165123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 10/06/2016] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Preconditioning stimuli conducted in remote organs can protect the heart against subsequent ischemic injury, but effects on arrhythmogenesis and sudden cardiac death (SCD) are unclear. Here, we investigated the effect of remote liver ischemia preconditioning (RLIPC) on ischemia/reperfusion (I/R)-induced cardiac arrhythmia and sudden cardiac death (SCD) in vivo, and determined the potential role of ERK/GSK-3βsignaling. METHODS/RESULTS Male Sprague Dawley rats were randomized to sham-operated, control, or RLIPC groups. RLIPC was induced by alternating four 5-minute cycles of liver ischemia with 5-minute intermittent reperfusions. To investigate I/R-induced arrhythmogenesis, hearts in each group were subsequently subjected to 5-minute left main coronary artery ligation followed by 20-minute reperfusion. RLIPC reduced post-I/R ventricular arrhythmias, and decreased the incidence of SCD >threefold. RLIPC increased phosphorylation of cardiac ERK1/2, and GSK-3β Ser9 but not Tyr216 post-I/R injury. Inhibition of either GSK-3β (with SB216763) or ERK1/2 (with U0126) abolished RLIPC-induced antiarrhythmic activity and GSK-3β Ser9 and ERK1/2 phosphorylation, leaving GSK-3β Tyr216 phosphorylation unchanged. CONCLUSIONS RLIPC exerts a powerful antiarrhythmic effect and reduces predisposition to post-IR SCD. The underlying mechanism of RLIPC cardioprotection against I/R-induced early arrhythmogenesis may involve ERK1/2/GSK-3β Ser9-dependent pathways.
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Affiliation(s)
- Zhaoyang Hu
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Sheng Hu
- Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shanxi, China
| | - Shuai Yang
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Mou Chen
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Ping Zhang
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jin Liu
- Laboratory of Anesthesiology & Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- * E-mail: (GWA); (JL)
| | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Dept. of Pharmacology and Dept. of Physiology and Biophysics, School of Medicine, University of California Irvine, Irvine, California, United States of America
- * E-mail: (GWA); (JL)
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13
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Abbott GW. Novel exon 1 protein-coding regions N-terminally extend human KCNE3 and KCNE4. FASEB J 2016; 30:2959-69. [PMID: 27162025 DOI: 10.1096/fj.201600467r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 04/26/2016] [Indexed: 01/02/2023]
Abstract
The 5 human (h)KCNE β subunits each regulate various cation channels and are linked to inherited cardiac arrhythmias. Reported here are previously undiscovered protein-coding regions in exon 1 of hKCNE3 and hKCNE4 that extend their encoded extracellular domains by 44 and 51 residues, which yields full-length proteins of 147 and 221 residues, respectively. Full-length hKCNE3 and hKCNE4 transcript and protein are expressed in multiple human tissues; for hKCNE4, only the longer protein isoform is detectable. Two-electrode voltage-clamp electrophysiology revealed that, when coexpressed in Xenopus laevis oocytes with various potassium channels, the newly discovered segment preserved conversion of KCNQ1 by hKCNE3 to a constitutively open channel, but prevented its inhibition of Kv4.2 and KCNQ4. hKCNE4 slowing of Kv4.2 inactivation and positive-shifted steady-state inactivation were also preserved in the longer form. In contrast, full-length hKCNE4 inhibition of KCNQ1 was limited to 40% at +40 mV vs. 80% inhibition by the shorter form, and augmentation of KCNQ4 activity by hKCNE4 was entirely abolished by the additional segment. Among the genome databases analyzed, the longer KCNE3 is confined to primates; full-length KCNE4 is widespread in vertebrates but is notably absent from Mus musculus Findings highlight unexpected KCNE gene diversity, raise the possibility of dynamic regulation of KCNE partner modulation via splice variation, and suggest that the longer hKCNE3 and hKCNE4 proteins should be adopted in future mechanistic and genetic screening studies.-Abbott, G. W. Novel exon 1 protein-coding regions N-terminally extend human KCNE3 and KCNE4.
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Affiliation(s)
- Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
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14
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Lisewski U, Koehncke C, Wilck N, Buschmeyer B, Pieske B, Roepke TK. Increased aldosterone-dependent Kv1.5 recycling predisposes to pacing-induced atrial fibrillation in Kcne3-/- mice. FASEB J 2016; 30:2476-89. [PMID: 26985008 DOI: 10.1096/fj.201600317r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/02/2016] [Indexed: 01/11/2023]
Abstract
Hyperaldosteronism is associated with an increased prevalence of atrial fibrillation (AF). Mutations in KCNE3 have been associated with AF, and Kcne3(-/-) mice exhibit hyperaldosteronism. In this study, we used recently developed Kcne3(-/-) mice to study atrial electrophysiology with respect to development of aldosterone-dependent AF. In invasive electrophysiology studies, Kcne3(-/-) mice displayed a reduced atrial effective refractory period (AERP) and inducible episodes of paroxysmal AF. The cellular arrhythmogenic correlate for AF predisposition was a significant increase in atrial Kv currents generated by the micromolar 4-aminopyridine-sensitive Kv current encoded by Kv1.5. Electrophysiological alterations in Kcne3(-/-) mice were aldosterone dependent and were associated with increased Rab4, -5, and -9-dependent recycling of Kv1.5 channels to the Z-disc/T-tubulus region and lateral membrane via activation of the Akt/AS160 pathway. Treatment with spironolactone inhibited Akt/AS160 phosphorylation, reduced Rab-dependent Kv1.5 recycling, normalized AERP and atrial Kv currents to the wild-type level, and reduced arrhythmia induction in Kcne3(-/-) mice. Kcne3 deletion in mice predisposes to AF by a heretofore unrecognized mechanism-namely, increased aldosterone-dependent Kv1.5 recycling via Rab GTPases. The findings uncover detailed molecular mechanisms underpinning a channelopathy-linked form of AF and emphasize the inevitability of considering extracardiac mechanisms in genetic arrhythmia syndromes.-Lisewski, U., Koehncke, C., Wilck, N., Buschmeyer, B., Pieske, B., Roepke, T. K. Increased aldosterone-dependent Kv1.5 recycling predisposes to pacing-induced atrial fibrillation in Kcne3(-/-) mice.
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Affiliation(s)
| | - Clemens Koehncke
- Experimental and Clinical Research Center, Berlin, Germany; Department of Cardiology, Campus Virchow, Universitätsmedizin Berlin, Berlin, Germany; and
| | - Nicola Wilck
- Experimental and Clinical Research Center, Berlin, Germany
| | | | - Burkert Pieske
- Department of Cardiology, Campus Virchow, Universitätsmedizin Berlin, Berlin, Germany; and
| | - Torsten K Roepke
- Experimental and Clinical Research Center, Berlin, Germany; Department of Cardiology and Angiology, Campus Mitte, Charité, Universitätsmedizin Berlin, Berlin, Germany
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15
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Hu Z, Crump SM, Zhang P, Abbott GW. Kcne2 deletion attenuates acute post-ischaemia/reperfusion myocardial infarction. Cardiovasc Res 2016; 110:227-37. [PMID: 26952045 DOI: 10.1093/cvr/cvw048] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 02/28/2016] [Indexed: 02/05/2023] Open
Abstract
AIMS Most cardiac arrhythmia-associated genes encode ion channel subunits and regulatory proteins that are also expressed outside the heart, suggesting that diseases linked to their disruption may be multifactorial. KCNE2 is a ubiquitously expressed potassium channel β subunit associated with cardiac arrhythmia, atherosclerosis, and myocardial infarction (MI) in human populations. Here, we tested the hypothesis that Kcne2 disruption in mice would influence the acute outcome of experimentally induced MI. METHODS AND RESULTS One-year-old male Kcne2⁺/⁺ and Kcne2⁻/⁻ mice were subjected to cardiac ischaemia/reperfusion injury (IRI) by left anterior descending coronary artery ligation. After reperfusion (3 h), infarct size and markers of tissue damage were quantified. Unexpectedly, post-reperfusion, Kcne2⁻/⁻ mice exhibited 40% lower infarct size, decreased myocardial apoptosis and damage, and more than two-fold lower serum levels of damage markers, lactate dehydrogenase and creatine kinase, than Kcne2⁺/⁺ mice. Kcne2 deletion, despite increasing normalized heart weight and prolonging baseline QTc by 70%, helped preserve post-infarct cardiac function (quantified by a Millar catheter), with parameters including left ventricular maximum pressure, max dP/dt (P < 0.01), contractility index, and pressure/time index (P < 0.05) all greater in Kcne2⁻/⁻ compared with Kcne2⁺/⁺ mice. Western blotting indicated two-fold-increased glycogen synthase kinase 3β (GSK-3β) phosphorylation (inactivation) before and after IRI (P < 0.05) in Kcne2⁻/⁻ mice compared with Kcne2⁺/⁺ mice. GSK-3β inhibition by SB216763 mimicked in Kcne2⁺/⁺ mice the cardioprotective effects of Kcne2 deletion, but did not further enhance them in Kcne2⁻/⁻mice, suggesting that GSK-3β inactivation was a primary cardioprotective mechanism arising from Kcne2 deletion. CONCLUSIONS Kcne2 deletion preconditions the heart, attenuating the acute tissue damage caused by an imposed IRI. The findings contribute further evidence that genetic disruption of arrhythmia-associated ion channel genes has cardiac ramifications beyond abnormal electrical activity.
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Affiliation(s)
- Zhaoyang Hu
- Laboratory of Anesthesiology and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Shawn M Crump
- Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Ping Zhang
- Laboratory of Anesthesiology and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
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16
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Abbott GW. KCNE1 and KCNE3: The yin and yang of voltage-gated K(+) channel regulation. Gene 2015; 576:1-13. [PMID: 26410412 DOI: 10.1016/j.gene.2015.09.059] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 09/03/2015] [Accepted: 09/22/2015] [Indexed: 12/20/2022]
Abstract
The human KCNE gene family comprises five genes encoding single transmembrane-spanning ion channel regulatory subunits. The primary function of KCNE subunits appears to be regulation of voltage-gated potassium (Kv) channels, and the best-understood KCNE complexes are with the KCNQ1 Kv α subunit. Here, we review the often opposite effects of KCNE1 and KCNE3 on Kv channel biology, with an emphasis on regulation of KCNQ1. Slow-activating IKs channel complexes formed by KCNQ1 and KCNE1 are essential for human ventricular myocyte repolarization, while constitutively active KCNQ1-KCNE3 channels are important in the intestine. Inherited sequence variants in human KCNE1 and KCNE3 cause cardiac arrhythmias but by different mechanisms, and each is important for hearing in unique ways. Because of their contrasting effects on KCNQ1 function, KCNE1 and KCNE3 have proved invaluable tools in the mechanistic understanding of how channel gating can be manipulated, and each may also provide a window into novel insights and new therapeutic opportunities in K(+) channel pharmacology. Finally, findings from studies of Kcne1(-/-) and Kcne3(-/-) mouse lines serve to illustrate the complexity of KCNE biology and KCNE-linked disease states.
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Affiliation(s)
- Geoffrey W Abbott
- Bioelectricity Laboratory, Dept. of Pharmacology and Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA; 360 Medical Surge II, Dept. of Pharmacology, School of Medicine, University of California, Irvine, CA 92697, USA.
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17
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Crump SM, Hu Z, Kant R, Levy DI, Goldstein SAN, Abbott GW. Kcne4 deletion sex- and age-specifically impairs cardiac repolarization in mice. FASEB J 2015; 30:360-9. [PMID: 26399785 DOI: 10.1096/fj.15-278754] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 09/08/2015] [Indexed: 02/05/2023]
Abstract
Myocardial repolarization capacity varies with sex, age, and pathology; the molecular basis for this variation is incompletely understood. Here, we show that the transcript for KCNE4, a voltage-gated potassium (Kv) channel β subunit associated with human atrial fibrillation, was 8-fold more highly expressed in the male left ventricle compared with females in young adult C57BL/6 mice (P < 0.05). Similarly, Kv current density was 25% greater in ventricular myocytes from young adult males (P < 0.05). Germ-line Kcne4 deletion eliminated the sex-specific Kv current disparity by diminishing ventricular fast transient outward current (Ito,f) and slowly activating K(+) current (IK,slow1). Kcne4 deletion also reduced Kv currents in male mouse atrial myocytes, by >45% (P < 0.001). As we previously found for Kv4.2 (which generates mouse Ito,f), heterologously expressed KCNE4 functionally regulated Kv1.5 (the Kv α subunit that generates IKslow1 in mice). Of note, in postmenopausal female mice, ventricular repolarization was impaired by Kcne4 deletion, and ventricular Kcne4 expression increased to match that of males. Moreover, castration diminished male ventricular Kcne4 expression 2.8-fold, whereas 5α-dihydrotestosterone (DHT) implants in castrated mice increased Kcne4 expression >3-fold (P = 0.01) to match noncastrated levels. KCNE4 is thereby shown to be a DHT-regulated determinant of cardiac excitability and a molecular substrate for sex- and age-dependent cardiac arrhythmogenesis.
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Affiliation(s)
- Shawn M Crump
- *Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA; Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Illinois, USA; and Department of Biochemistry, Brandeis University, Waltham, Massachusetts, USA
| | - Zhaoyang Hu
- *Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA; Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Illinois, USA; and Department of Biochemistry, Brandeis University, Waltham, Massachusetts, USA
| | - Ritu Kant
- *Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA; Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Illinois, USA; and Department of Biochemistry, Brandeis University, Waltham, Massachusetts, USA
| | - Daniel I Levy
- *Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA; Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Illinois, USA; and Department of Biochemistry, Brandeis University, Waltham, Massachusetts, USA
| | - Steve A N Goldstein
- *Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA; Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Illinois, USA; and Department of Biochemistry, Brandeis University, Waltham, Massachusetts, USA
| | - Geoffrey W Abbott
- *Bioelectricity Laboratory, Department of Pharmacology and Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA; Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Illinois, USA; and Department of Biochemistry, Brandeis University, Waltham, Massachusetts, USA
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18
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Crump SM, Abbott GW. Arrhythmogenic KCNE gene variants: current knowledge and future challenges. Front Genet 2014; 5:3. [PMID: 24478792 PMCID: PMC3900874 DOI: 10.3389/fgene.2014.00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 01/04/2014] [Indexed: 11/13/2022] Open
Abstract
There are twenty-five known inherited cardiac arrhythmia susceptibility genes, all of which encode either ion channel pore-forming subunits or proteins that regulate aspects of ion channel biology such as function, trafficking, and localization. The human KCNE gene family comprises five potassium channel regulatory subunits, sequence variants in each of which are associated with cardiac arrhythmias. KCNE gene products exhibit promiscuous partnering and in some cases ubiquitous expression, hampering efforts to unequivocally correlate each gene to specific native potassium currents. Likewise, deducing the molecular etiology of cardiac arrhythmias in individuals harboring rare KCNE gene variants, or more common KCNE polymorphisms, can be challenging. In this review we provide an update on putative arrhythmia-causing KCNE gene variants, and discuss current thinking and future challenges in the study of molecular mechanisms of KCNE-associated cardiac rhythm disturbances.
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Affiliation(s)
- Shawn M Crump
- Bioelectricity Laboratory, Department of Pharmacology, Department of Physiology and Biophysics, School of Medicine, University of California Irvine, CA, USA
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Pharmacology, Department of Physiology and Biophysics, School of Medicine, University of California Irvine, CA, USA
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