1
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Chakraborty A, Paynter A, Szendrey M, Cornwell JD, Li W, Guo J, Yang T, Du Y, Wang T, Zhang S. Ubiquitination is involved in PKC-mediated degradation of cell surface Kv1.5 channels. J Biol Chem 2024; 300:107483. [PMID: 38897569 DOI: 10.1016/j.jbc.2024.107483] [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: 02/09/2024] [Revised: 05/30/2024] [Accepted: 06/12/2024] [Indexed: 06/21/2024] Open
Abstract
The voltage-gated Kv1.5 potassium channel, conducting the ultra-rapid delayed rectifier K+ current (IKur) in human cells, plays important roles in the repolarization of atrial action potentials and regulation of the vascular tone. We previously reported that activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) induces endocytic degradation of cell-surface Kv1.5 channels, and a point mutation removing the phosphorylation site, T15A, in the N terminus of Kv1.5 abolished the PMA-effect. In the present study, using mutagenesis, patch clamp recording, Western blot analysis, and immunocytochemical staining, we demonstrate that ubiquitination is involved in the PMA-mediated degradation of mature Kv1.5 channels. Since the expression of the Kv1.4 channel is unaffected by PMA treatment, we swapped the N- and/or C-termini between Kv1.5 and Kv1.4. We found that the N-terminus alone did not but both N- and C-termini of Kv1.5 did confer PMA sensitivity to mature Kv1.4 channels, suggesting the involvement of Kv1.5 C-terminus in the channel ubiquitination. Removal of each of the potential ubiquitination residue Lysine at position 536, 565, and 591 by Arginine substitution (K536R, K565R, and K591R) had little effect, but removal of all three Lysine residues with Arginine substitution (3K-R) partially reduced PMA-mediated Kv1.5 degradation. Furthermore, removing the cysteine residue at position 604 by Serine substitution (C604S) drastically reduced PMA-induced channel degradation. Removal of the three Lysines and Cys604 with a quadruple mutation (3K-R/C604S) or a truncation mutation (Δ536) completely abolished the PKC activation-mediated degradation of Kv1.5 channels. These results provide mechanistic insight into PKC activation-mediated Kv1.5 degradation.
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Affiliation(s)
- Ananya Chakraborty
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Amanda Paynter
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Mark Szendrey
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - James D Cornwell
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Wentao Li
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Jun Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Tonghua Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Yuan Du
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Tingzhong Wang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
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2
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Árpádffy-Lovas T, Mohammed ASA, Naveed M, Koncz I, Baláti B, Bitay M, Jost N, Nagy N, Baczkó I, Virág L, Varró A. Species dependent differences in the inhibition of various potassium currents and in their effects on repolarization in cardiac ventricular muscle. Can J Physiol Pharmacol 2022; 100:880-889. [PMID: 35442802 DOI: 10.1139/cjpp-2022-0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Even though rodents are accessible model animals, their electrophysiological properties are deeply different from that of human, making the translation of rat studies to human rather difficult. We compared the mechanisms of ventricular repolarization in various animal models to those of human by measuring cardiac ventricular action potentials from ventricular papillary muscle preparations using conventional microelectrodes, and applying selective inhibitors of various potassium transmembrane ion currents. Inhibition of the IK1 current (10 µM barium chloride) significantly prolonged rat ventricular repolarization, but only slightly prolonged it in dog, and did not affect it in human. On the contrary, IKr inhibition (50 nM dofetilide) significantly prolonged repolarization in human, rabbit, and dog, but not in rat. Inhibition of the IKur current (1 µM XEN-D0101) only prolonged rat ventricular repolarization, and had no effect in human or dog. Inhibition of the IKs (500 nM HMR-1556) and Ito currents (100 µM chromanol-293B) elicited similar effects in all investigated species. We conclude that dog ventricular preparations have the strongest, and rat ventricular preparations have the weakest translational value in cardiac electrophysiological experiments.
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Affiliation(s)
- Tamás Árpádffy-Lovas
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Aiman Saleh A Mohammed
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Muhammad Naveed
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - István Koncz
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Beáta Baláti
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Miklós Bitay
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Cardiac Surgery, Second Department of Internal Medicine and Cardiology Center, Szeged, Csongrád, Hungary;
| | - Norbert Jost
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary.,Eötvös Loránd Research Network, 579839, ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary, Budapest, Hungary;
| | - Norbert Nagy
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharamacotherapy, Szeged, Csongrád, Hungary.,Eötvös Loránd Research Network, 579839, ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary, Budapest, Hungary;
| | - István Baczkó
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - László Virág
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - András Varró
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary.,Eötvös Loránd Research Network, 579839, ELKH-SZTE Research Group of Cardiovascular Pharmacology, Budapest, Hungary;
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3
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Lee HM, Hahn SJ, Choi BH. The antidiabetic drug rosiglitazone blocks Kv1.5 potassium channels in an open state. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY 2022; 26:135-144. [PMID: 35203063 PMCID: PMC8890944 DOI: 10.4196/kjpp.2022.26.2.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 11/15/2022]
Abstract
An antidiabetic drug, rosiglitazone is a member of the drug class of thiazolidinedione. Although restrictions on use due to the possibility of heart toxicity have been removed, it is still a drug that is concerned about side effects on the heart. We here examined, using Chinese hamster ovary cells, the action of rosiglitazone on Kv1.5 channels, which is a major determinant of the duration of cardiac action potential. Rosiglitazone rapidly and reversibly inhibited Kv1.5 currents in a concentration-dependent manner (IC50 = 18.9 µM) and accelerated the decay of Kv1.5 currents without modifying the activation kinetics. In addition, the deactivation of Kv1.5 current, assayed with tail current, was slowed by the drug. All of the results as well as the use-dependence of the rosiglitazone-mediated blockade indicate that rosiglitazone acts on Kv1.5 channels as an open channel blocker. This study suggests that the cardiac side effects of rosiglitazone might be mediated in part by suppression of Kv1.5 channels, and therefore, raises a concern of using the drug for diabetic therapeutics.
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Affiliation(s)
- Hyang Mi Lee
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
| | - Sang June Hahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Bok Hee Choi
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
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4
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Filatova TS, Abramochkin DV, Pavlova NS, Pustovit KB, Konovalova OP, Kuzmin VS, Dobrzynski H. Repolarizing potassium currents in working myocardium of Japanese quail: a novel translational model for cardiac electrophysiology. Comp Biochem Physiol A Mol Integr Physiol 2021; 255:110919. [DOI: 10.1016/j.cbpa.2021.110919] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/06/2021] [Accepted: 02/06/2021] [Indexed: 12/14/2022]
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5
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Du Y, Wang T, Guo J, Li W, Yang T, Szendrey M, Zhang S. Kv1.5 channels are regulated by PKC-mediated endocytic degradation. J Biol Chem 2021; 296:100514. [PMID: 33676894 PMCID: PMC8050386 DOI: 10.1016/j.jbc.2021.100514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/28/2021] [Accepted: 03/03/2021] [Indexed: 11/28/2022] Open
Abstract
The voltage-gated potassium channel Kv1.5 plays important roles in the repolarization of atrial action potentials and regulation of the vascular tone. While the modulation of Kv1.5 function has been well studied, less is known about how the protein levels of Kv1.5 on the cell membrane are regulated. Here, through electrophysiological and biochemical analyses of Kv1.5 channels heterologously expressed in HEK293 cells and neonatal rat ventricular myocytes, as well as native Kv1.5 in human induced pluripotent stem cell (iPSC)-derived atrial cardiomyocytes, we found that activation of protein kinase C (PKC) with phorbol 12-myristate 13-acetate (PMA, 10 nM) diminished Kv1.5 current (IKv1.5) and protein levels of Kv1.5 in the plasma membrane. Mechanistically, PKC activation led to monoubiquitination and degradation of the mature Kv1.5 proteins. Overexpression of Vps24, a protein that sorts transmembrane proteins into lysosomes via the multivesicular body (MVB) pathway, accelerated, whereas the lysosome inhibitor bafilomycin A1 completely prevented PKC-mediated Kv1.5 degradation. Kv1.5, but not Kv1.1, Kv1.2, Kv1.3, or Kv1.4, was uniquely sensitive to PMA treatment. Sequence alignments suggested that residues within the N terminus of Kv1.5 are essential for PKC-mediated Kv1.5 reduction. Using N-terminal truncation as well as site-directed mutagenesis, we identified that Thr15 is the target site for PKC that mediates endocytic degradation of Kv1.5 channels. These findings indicate that alteration of protein levels in the plasma membrane represents an important regulatory mechanism of Kv1.5 channel function under PKC activation conditions.
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Affiliation(s)
- Yuan Du
- Department of Cardiovascular Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Tingzhong Wang
- Department of Cardiovascular Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Jun Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Wentao Li
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Tonghua Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Mark Szendrey
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
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6
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Zhou HS, Peng DW, Lai YY, Li Q, Zhao JF, Deng CY, Yang H, Li T, Wang ZY, Xu YW, Xue YM, Wu SL, Guo HM, Rao F. Activation of PKCα participates in the reduction of Ikur in atrial myocytes induced by tumour necrosis factor-α. Clin Exp Pharmacol Physiol 2021; 48:435-442. [PMID: 32966616 DOI: 10.1111/1440-1681.13407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/09/2020] [Accepted: 09/11/2020] [Indexed: 11/30/2022]
Abstract
The atrial-specific ultra-rapid delayed rectifier K+ current (Ikur) plays an important role in the progression of atrial fibrillation (AF). Because inflammation is known to lead to the onset of AF, we aimed to investigate whether tumour necrosis factor-α (TNF-α) played a role in regulating Ikur and the potential signalling pathways involved. Whole-cell patch-clamp and biochemical assays were used to study the regulation and expression of Ikur in myocytes and in tissues from left atrial appendages (LAAs) obtained from patients with sinus rhythm (SR) or AF, as well as in rat cardiomyocytes (H9c2 cells) and mouse atrial myocytes (HL-1 cells). Ikur current density was markedly reduced in atrial myocytes from AF patients compared with SR controls. Reduction of Kv1.5 protein levels was accompanied by increased expression of TNF-α and protein kinase C (PKC)α activation in AF patients. Treatment with TNF-α dose-dependently reduced Ikur and protein expression of Kv1.5 but not Kv3.1b in H9c2 cells and HL-1 cells. TNF-α also increased activity of PKCα. Specific PKCα inhibitor Gö6976 alleviated the reduction in Ikur induced by TNF-α, but not the reduction in Kv1.5 protein. TNF-α was involved in the electrical remodelling associated with AF, probably by depressing Ikur in atrial myocytes via activation of PKCα.
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Affiliation(s)
- Hui-Shan Zhou
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Panyu Central Hospital, Guangzhou, China
| | - De-Wei Peng
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Ying-Yu Lai
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Qian Li
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Jun-Fei Zhao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Chun-Yu Deng
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Hui Yang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Teng Li
- Arrhythmia Department, Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, China
| | - Zhao-Yu Wang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Yu-Wen Xu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Yu-Mei Xue
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Shu-Lin Wu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Hui-Ming Guo
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Fang Rao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
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7
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Saadeh K, Fazmin IT. Mitochondrial Dysfunction Increases Arrhythmic Triggers and Substrates; Potential Anti-arrhythmic Pharmacological Targets. Front Cardiovasc Med 2021; 8:646932. [PMID: 33659284 PMCID: PMC7917191 DOI: 10.3389/fcvm.2021.646932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/26/2021] [Indexed: 12/31/2022] Open
Abstract
Incidence of cardiac arrhythmias increases significantly with age. In order to effectively stratify arrhythmic risk in the aging population it is crucial to elucidate the relevant underlying molecular mechanisms. The changes underlying age-related electrophysiological disruption appear to be closely associated with mitochondrial dysfunction. Thus, the present review examines the mechanisms by which age-related mitochondrial dysfunction promotes arrhythmic triggers and substrate. Namely, via alterations in plasmalemmal ionic currents (both sodium and potassium), gap junctions, cellular Ca2+ homeostasis, and cardiac fibrosis. Stratification of patients' mitochondrial function status permits application of appropriate anti-arrhythmic therapies. Here, we discuss novel potential anti-arrhythmic pharmacological interventions that specifically target upstream mitochondrial function and hence ameliorates the need for therapies targeting downstream changes which have constituted traditional antiarrhythmic therapy.
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Affiliation(s)
- Khalil Saadeh
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Ibrahim Talal Fazmin
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
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8
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Lebedeva NB, Hoffman VV. [Current understanding of the role of age-related hypogonadism in the development of cardiovascular diseases]. TERAPEVT ARKH 2021; 93:79-83. [PMID: 33720630 DOI: 10.26442/00403660.2021.01.200597] [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: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 11/22/2022]
Abstract
The literature review presents novel data on the prevalence of age-related hypogonadism and its relationship with aging, its impact on the circulatory system and cardiovascular diseases. This review summarizes the methods for diagnosing age-related hypogonadism, its association with traditional cardiovascular risk factors such as dyslipidemia, insulin resistance and diabetes mellitus, obesity, arterial hypertension. The mechanisms of the possible direct effect of testosterone on endothelium and vascular tone, the role of hormone replacement therapy as a way of preventing cardiovascular diseases are discussed.
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Affiliation(s)
- N B Lebedeva
- Research Institute for Complex Issues of Cardiovascular Diseases
| | - V V Hoffman
- Primary Healthcare Unit of the Ministry of Internal Affairs of the Russian Federation for the Kemerovo Region
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9
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Asfaw TN, Tyan L, Glukhov AV, Bondarenko VE. A compartmentalized mathematical model of mouse atrial myocytes. Am J Physiol Heart Circ Physiol 2020; 318:H485-H507. [PMID: 31951471 DOI: 10.1152/ajpheart.00460.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Various experimental mouse models are extensively used to research human diseases, including atrial fibrillation, the most common cardiac rhythm disorder. Despite this, there are no comprehensive mathematical models that describe the complex behavior of the action potential and [Ca2+]i transients in mouse atrial myocytes. Here, we develop a novel compartmentalized mathematical model of mouse atrial myocytes that combines the action potential, [Ca2+]i dynamics, and β-adrenergic signaling cascade for a subpopulation of right atrial myocytes with developed transverse-axial tubule system. The model consists of three compartments related to β-adrenergic signaling (caveolae, extracaveolae, and cytosol) and employs local control of Ca2+ release. It also simulates ionic mechanisms of action potential generation and describes atrial-specific Ca2+ handling as well as frequency dependences of the action potential and [Ca2+]i transients. The model showed that the T-type Ca2+ current significantly affects the later stage of the action potential, with little effect on [Ca2+]i transients. The block of the small-conductance Ca2+-activated K+ current leads to a prolongation of the action potential at high intracellular Ca2+. Simulation results obtained from the atrial model cells were compared with those from ventricular myocytes. The developed model represents a useful tool to study complex electrical properties in the mouse atria and could be applied to enhance the understanding of atrial physiology and arrhythmogenesis.NEW & NOTEWORTHY A new compartmentalized mathematical model of mouse right atrial myocytes was developed. The model simulated action potential and Ca2+ dynamics at baseline and after stimulation of the β-adrenergic signaling system. Simulations showed that the T-type Ca2+ current markedly prolonged the later stage of atrial action potential repolarization, with a minor effect on [Ca2+]i transients. The small-conductance Ca2+-activated K+ current block resulted in prolongation of the action potential only at the relatively high intracellular Ca2+.
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Affiliation(s)
- Tesfaye Negash Asfaw
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia
| | - Leonid Tyan
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Alexey V Glukhov
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Vladimir E Bondarenko
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia.,Neuroscience Institute, Georgia State University, Atlanta, Georgia
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10
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Xiao GS, Zhang YH, Wang Y, Sun HY, Baumgarten CM, Li GR. Noradrenaline up-regulates volume-regulated chloride current by PKA-independent cAMP/exchange protein activated by cAMP pathway in human atrial myocytes. Br J Pharmacol 2018; 175:3422-3432. [PMID: 29900525 DOI: 10.1111/bph.14392] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 05/29/2018] [Accepted: 06/05/2018] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Adrenergic regulation of cell volume-regulated chloride current (ICl.vol ) is species-dependent. The present study investigates the mechanism underlying adrenergic regulation of ICl.vol in human atrial myocytes. EXPERIMENTAL APPROACH Conventional whole-cell patch voltage-clamp techniques were used to record membrane current in human atrial myocytes. ICl.vol was evoked by hyposmotic bath solution (0.6 times isosmotic, 0.6 T). KEY RESULTS ICl.vol was augmented by noradrenaline (1 μM) during cell swelling in 0.6 T but not under isosmotic (1 T) conditions. Up-regulation of ICl.vol in 0.6 T was blocked by the β-adrenoceptor antagonist propranolol (2 μM), but not by the α1 -adrenoceptor antagonist prazosin (2 μM). This β-adrenergic response involved cAMP but was independent of PKA; the protein kinase inhibitor H-89 (2 μM) or PKI (10 μM in pipette solution) failed to prevent ICl.vol up-regulation by noradrenaline. Moreover, the PI3K/PKB inhibitor LY294002 (50 μM) and the PKG inhibitor KT5823 (10 μM) did not affect noradrenaline-induced increases in ICl.vol . Interestingly, the exchange protein directly activated by cAMP (Epac) agonist 8-pCPT-2'-O-Me-cAMP (50 μM) also up-regulated ICl.vol , and the noradrenaline-induced increase of ICl.vol in 0.6 T was reversed or prevented by the Epac inhibitor ESI-09 (10 μM). CONCLUSION AND IMPLICATIONS These data show that ICl.vol evoked by cell swelling of human atrial myocytes is up-regulated by noradrenaline via a PKA-independent cAMP/Epac pathway in human atrial myocytes. cAMP/Epac-induced ICl.vol is expected to shorten action potential duration during human atrial myocytes swelling and may be involved in abnormal cardiac electrical activity during cardiac pathologies that evoke β-adrenoceptor signalling.
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Affiliation(s)
- Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Yan-Hui Zhang
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, Fujian, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Clive M Baumgarten
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - Gui-Rong Li
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
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11
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Sessa M, Mascolo A, Mortensen RN, Andersen MP, Rosano GMC, Capuano A, Rossi F, Gislason G, Enghusen-Poulsen H, Torp-Pedersen C. Relationship between heart failure, concurrent chronic obstructive pulmonary disease and beta-blocker use: a Danish nationwide cohort study. Eur J Heart Fail 2017; 20:548-556. [PMID: 29159953 DOI: 10.1002/ejhf.1045] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 08/30/2017] [Accepted: 09/24/2017] [Indexed: 12/22/2022] Open
Abstract
AIMS To compare the hazard of all-cause, chronic obstructive pulmonary disease (COPD) and heart failure (HF) hospitalization in carvedilol vs. metoprolol/bisoprolol/nebivolol users with COPD and concurrent HF from 2009 to 2012, and to evaluate the use and persistence in treatment of these β-blockers, their impact on the risk of COPD-related hospitalization, and the factors important for their selection. METHODS AND RESULTS Cox and logistic regression were used for both unadjusted and adjusted analyses. Carvedilol users had a higher hazard of being hospitalized for HF compared with metoprolol/bisoprolol/nebivolol users in both the unadjusted [hazard ratio (HR) 1.74; 95% confidence interval (CI) 1.65-1.83] and adjusted (HR 1.61; 95% CI 1.52-1.70) analyses. No significant differences were found for all-cause and COPD hospitalization between the two groups. Carvedilol users had a significant lower restricted mean persistence time than metoprolol/bisoprolol/nebivolol users. Patients exposed to carvedilol had an odds ratio (OR) of 1.38 (95% CI 1.23-1.56) for being hospitalized due to COPD within 60 days after redeeming the first carvedilol prescription, which was similar to that observed in metoprolol/bisoprolol/nebivolol users (OR 1.37; 95% CI 1.27-1.48). Patients with concurrent chronic kidney disease had a higher probability of receiving carvedilol (OR 1.16; 95% CI 1.04-1.29). CONCLUSION Carvedilol prescription carried an increased hazard of HF hospitalization and lower restricted mean persistence time among patients with COPD and concurrent HF. Additionally, we found a widespread phenomenon of carvedilol prescription at variance with the European Society of Cardiology guidelines and potential for improving the proportion of patients treated with β-blockers.
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Affiliation(s)
- Maurizio Sessa
- Department of Experimental Medicine, Section of Pharmacology 'L. Donatelli', University of Campania 'L. Vanvitelli', Naples, Italy.,Unit of Epidemiology and Biostatistics, Aalborg University Hospital, Aalborg, Denmark
| | - Annamaria Mascolo
- Department of Experimental Medicine, Section of Pharmacology 'L. Donatelli', University of Campania 'L. Vanvitelli', Naples, Italy
| | | | | | - Giuseppe Massimo Claudio Rosano
- San Raffaele Pisana Hospital IRCCS, Rome, Italy.,Cardiovascular and Cell Sciences Research Institute, St. George's University of London, London, UK
| | - Annalisa Capuano
- Department of Experimental Medicine, Section of Pharmacology 'L. Donatelli', University of Campania 'L. Vanvitelli', Naples, Italy
| | - Francesco Rossi
- Department of Experimental Medicine, Section of Pharmacology 'L. Donatelli', University of Campania 'L. Vanvitelli', Naples, Italy
| | - Gunnar Gislason
- Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Hellerup, Denmark.,The Danish Heart Foundation, Copenhagen K, Copenhagen, Denmark.,The National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark
| | | | - Christian Torp-Pedersen
- Unit of Epidemiology and Biostatistics, Aalborg University Hospital, Aalborg, Denmark.,Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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12
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Aguilar M, Feng J, Vigmond E, Comtois P, Nattel S. Rate-Dependent Role of I Kur in Human Atrial Repolarization and Atrial Fibrillation Maintenance. Biophys J 2017; 112:1997-2010. [PMID: 28494969 DOI: 10.1016/j.bpj.2017.03.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/06/2017] [Accepted: 03/23/2017] [Indexed: 11/24/2022] Open
Abstract
The atrial-specific ultrarapid delayed rectifier K+ current (IKur) inactivates slowly but completely at depolarized voltages. The consequences for IKur rate-dependence have not been analyzed in detail and currently available mathematical action-potential (AP) models do not take into account experimentally observed IKur inactivation dynamics. Here, we developed an updated formulation of IKur inactivation that accurately reproduces time-, voltage-, and frequency-dependent inactivation. We then modified the human atrial cardiomyocyte Courtemanche AP model to incorporate realistic IKur inactivation properties. Despite markedly different inactivation dynamics, there was no difference in AP parameters across a wide range of stimulation frequencies between the original and updated models. Using the updated model, we showed that, under physiological stimulation conditions, IKur does not inactivate significantly even at high atrial rates because the transmembrane potential spends little time at voltages associated with inactivation. Thus, channel dynamics are determined principally by activation kinetics. IKur magnitude decreases at higher rates because of AP changes that reduce IKur activation. Nevertheless, the relative contribution of IKur to AP repolarization increases at higher frequencies because of reduced activation of the rapid delayed-rectifier current IKr. Consequently, IKur block produces dose-dependent termination of simulated atrial fibrillation (AF) in the absence of AF-induced electrical remodeling. The inclusion of AF-related ionic remodeling stabilizes simulated AF and greatly reduces the predicted antiarrhythmic efficacy of IKur block. Our results explain a range of experimental observations, including recently reported positive rate-dependent IKur-blocking effects on human atrial APs, and provide insights relevant to the potential value of IKur as an antiarrhythmic target for the treatment of AF.
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Affiliation(s)
- Martin Aguilar
- Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Québec, Canada; Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montreal, Québec, Canada
| | | | - Edward Vigmond
- L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Fondation Université de Bordeaux, Hôpital Xavier-Arnozan, Pessac, France; Institut de Mathématiques de Bordeaux, Université de Bordeaux, Talence, France
| | - Philippe Comtois
- Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Québec, Canada; Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montreal, Québec, Canada
| | - Stanley Nattel
- Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Québec, Canada; Department of Medicine, McGill University, Montreal, Québec, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec, Canada; Department of Medicine, Université de Montréal, Montreal, Québec, Canada; West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.
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13
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Xiao GS, Zhang YH, Wu W, Sun HY, Wang Y, Li GR. Genistein and tyrphostin AG556 decrease ultra-rapidly activating delayed rectifier K + current of human atria by inhibiting EGF receptor tyrosine kinase. Br J Pharmacol 2017; 174:454-467. [PMID: 28072464 DOI: 10.1111/bph.13710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 12/16/2016] [Accepted: 01/05/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE The ultra-rapidly activating delayed rectifier K+ current IKur (encoded by Kv 1.5 or KCNA5) plays an important role in human atrial repolarization. The present study investigates the regulation of this current by protein tyrosine kinases (PTKs). EXPERIMENTAL APPROACH Whole-cell patch voltage clamp technique and immunoprecipitation and Western blotting analysis were used to investigate whether the PTK inhibitors genistein, tyrphostin AG556 (AG556) and PP2 regulate human atrial IKur and hKv1.5 channels stably expressed in HEK 293 cells. KEY RESULTS Human atrial IKur was decreased by genistein (a broad-spectrum PTK inhibitor) and AG556 (a highly selective EGFR TK inhibitor) in a concentration-dependent manner. Inhibition of IKur induced by 30 μM genistein or 10 μM AG556 was significantly reversed by 1 mM orthovanadate (a protein tyrosine phosphatase inhibitor). Similar results were observed in HEK 293 cells stably expressing hKv 1.5 channels. On the other hand, the Src family kinase inhibitor PP2 (1 μM) slightly enhanced IKur and hKv 1.5 current, and the current increase was also reversed by orthovanadate. Immunoprecipitation and Western blotting analysis showed that genistein, AG556, and PP2 decreased tyrosine phosphorylation of hKv 1.5 channels and that the decrease was countered by orthovanadate. CONCLUSION AND IMPLICATIONS The PTK inhibitors genistein and AG556 decrease human atrial IKur and cloned hKv 1.5 channels by inhibiting EGFR TK, whereas the Src kinase inhibitor PP2 increases IKur and hKv 1.5 current. These results imply that EGFR TK and the soluble Src kinases may have opposite effects on human atrial IKur .
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Affiliation(s)
- Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Yan-Hui Zhang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Wei Wu
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Gui-Rong Li
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
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14
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Edwards AG, Louch WE. Species-Dependent Mechanisms of Cardiac Arrhythmia: A Cellular Focus. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2017; 11:1179546816686061. [PMID: 28469490 PMCID: PMC5392019 DOI: 10.1177/1179546816686061] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/20/2016] [Indexed: 12/17/2022]
Abstract
Although ventricular arrhythmia remains a leading cause of morbidity and mortality, available antiarrhythmic drugs have limited efficacy. Disappointing progress in the development of novel, clinically relevant antiarrhythmic agents may partly be attributed to discrepancies between humans and animal models used in preclinical testing. However, such differences are at present difficult to predict, requiring improved understanding of arrhythmia mechanisms across species. To this end, we presently review interspecies similarities and differences in fundamental cardiomyocyte electrophysiology and current understanding of the mechanisms underlying the generation of afterdepolarizations and reentry. We specifically highlight patent shortcomings in small rodents to reproduce cellular and tissue-level arrhythmia substrate believed to be critical in human ventricle. Despite greater ease of translation from larger animal models, discrepancies remain and interpretation can be complicated by incomplete knowledge of human ventricular physiology due to low availability of explanted tissue. We therefore point to the benefits of mathematical modeling as a translational bridge to understanding and treating human arrhythmia.
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Affiliation(s)
- Andrew G Edwards
- Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway.,Center for Cardiological Innovation, Simula Research Laboratory, Lysaker, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
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15
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Bohnen MS, Peng G, Robey SH, Terrenoire C, Iyer V, Sampson KJ, Kass RS. Molecular Pathophysiology of Congenital Long QT Syndrome. Physiol Rev 2017; 97:89-134. [PMID: 27807201 PMCID: PMC5539372 DOI: 10.1152/physrev.00008.2016] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ion channels represent the molecular entities that give rise to the cardiac action potential, the fundamental cellular electrical event in the heart. The concerted function of these channels leads to normal cyclical excitation and resultant contraction of cardiac muscle. Research into cardiac ion channel regulation and mutations that underlie disease pathogenesis has greatly enhanced our knowledge of the causes and clinical management of cardiac arrhythmia. Here we review the molecular determinants, pathogenesis, and pharmacology of congenital Long QT Syndrome. We examine mechanisms of dysfunction associated with three critical cardiac currents that comprise the majority of congenital Long QT Syndrome cases: 1) IKs, the slow delayed rectifier current; 2) IKr, the rapid delayed rectifier current; and 3) INa, the voltage-dependent sodium current. Less common subtypes of congenital Long QT Syndrome affect other cardiac ionic currents that contribute to the dynamic nature of cardiac electrophysiology. Through the study of mutations that cause congenital Long QT Syndrome, the scientific community has advanced understanding of ion channel structure-function relationships, physiology, and pharmacological response to clinically employed and experimental pharmacological agents. Our understanding of congenital Long QT Syndrome continues to evolve rapidly and with great benefits: genotype-driven clinical management of the disease has improved patient care as precision medicine becomes even more a reality.
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Affiliation(s)
- M S Bohnen
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - G Peng
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - S H Robey
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - C Terrenoire
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - V Iyer
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - K J Sampson
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - R S Kass
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
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16
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Ríos-Pérez EB, García-Castañeda M, Monsalvo-Villegas A, Avila G. Chronic atrial ionic remodeling by aldosterone: potentiation of L-type Ca 2+ channels and its arrhythmogenic significance. Pflugers Arch 2016; 468:1823-1835. [PMID: 27631154 DOI: 10.1007/s00424-016-1876-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/31/2016] [Accepted: 09/05/2016] [Indexed: 11/25/2022]
Abstract
It is widely accepted that aldosterone induces atrial fibrillation (AF) by promoting structural changes, but its effects on the function of primary atrial myocytes remain unknown. We have investigated this point in adult rat atrial myocytes, chronically exposed to the hormone. This treatment produced larger amplitude of Ca2+ transients, longer action potential (AP) duration, and higher incidence of unsynchronized Ca2+ oscillations. Moreover, it also gave rise to increases in both cell membrane capacitance (Cm, 30 %) and activity of L-type Ca2+ channels (LTCCs, 100 %). Concerning K+ currents, a twofold increase was also observed, but only in a delayed rectifier component (IKsus). Interestingly, the maximal conductance (Gmax) of Na+ channels was also enhanced, but it occurred in the face of a negative shift in the voltage dependence of inactivation. Thus, at physiological potentials, a decreased fraction of available channels neutralized the effect on GNa-max. With regard to the effects on both Cm and LTCCs, they involved activation of mineralocorticoid receptors (MRs), were dose-dependent (EC50 ∼20-130 nM), and developed and recovered in days. Neither gating currents nor protein levels of LTCCs were altered. Instead, the effect on LTCCs was mimicked by cAMP, reverted by a PKA inhibitor, and attenuated by a nitric oxide donor (short-term exposures). Both EGTA and the antioxidant NAC prevented the increase in Cm, without significantly interfering with the upregulation of LTCCs. Overall, these results show that chronic exposures to aldosterone result in dire functional changes at the single myocyte level, which may explain the link between aldosteronism and AF.
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Affiliation(s)
- Erick B Ríos-Pérez
- Department of Biochemistry, Cinvestav-IPN, AP 14-740, México City, DF 07000, México
| | | | | | - Guillermo Avila
- Department of Biochemistry, Cinvestav-IPN, AP 14-740, México City, DF 07000, México.
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17
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Wu W, Sanguinetti MC. Molecular Basis of Cardiac Delayed Rectifier Potassium Channel Function and Pharmacology. Card Electrophysiol Clin 2016; 8:275-84. [PMID: 27261821 DOI: 10.1016/j.ccep.2016.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human cardiomyocytes express 3 distinct types of delayed rectifier potassium channels. Human ether-a-go-go-related gene (hERG) channels conduct the rapidly activating current IKr; KCNQ1/KCNE1 channels conduct the slowly activating current IKs; and Kv1.5 channels conduct an ultrarapid activating current IKur. Here the authors provide a general overview of the mechanistic and structural basis of ion selectivity, gating, and pharmacology of the 3 types of cardiac delayed rectifier potassium ion channels. Most blockers bind to S6 residues that line the central cavity of the channel, whereas activators interact with the channel at 4 symmetric binding sites outside the cavity.
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Affiliation(s)
- Wei Wu
- Department of Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, 95 South 2000 East, Salt Lake City, UT 84112, USA
| | - Michael C Sanguinetti
- Department of Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, 95 South 2000 East, Salt Lake City, UT 84112, USA.
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18
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Moghtadaei M, Polina I, Rose RA. Electrophysiological effects of natriuretic peptides in the heart are mediated by multiple receptor subtypes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 120:37-49. [DOI: 10.1016/j.pbiomolbio.2015.12.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/25/2015] [Accepted: 12/02/2015] [Indexed: 12/13/2022]
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19
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Lee HM, Hahn SJ, Choi BH. Blockade of Kv1.5 by paroxetine, an antidepressant drug. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 20:75-82. [PMID: 26807026 PMCID: PMC4722194 DOI: 10.4196/kjpp.2016.20.1.75] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 09/23/2015] [Accepted: 10/21/2015] [Indexed: 12/24/2022]
Abstract
Paroxetine, a selective serotonin reuptake inhibitor (SSRI), has been reported to have an effect on several ion channels including human ether-a-go-go-related gene in a SSRI-independent manner. These results suggest that paroxetine may cause side effects on cardiac system. In this study, we investigated the effect of paroxetine on Kv1.5, which is one of cardiac ion channels. The action of paroxetine on the cloned neuronal rat Kv1.5 channels stably expressed in Chinese hamster ovary cells was investigated using the whole-cell patch-clamp technique. Paroxetine reduced Kv1.5 whole-cell currents in a reversible concentration-dependent manner, with an IC 50 value and a Hill coefficient of 4.11 µM and 0.98, respectively. Paroxetine accelerated the decay rate of inactivation of Kv1.5 currents without modifying the kinetics of current activation. The inhibition increased steeply between -30 and 0 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to 0 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance δ of 0.32. The binding (k+1) and unbinding (k-1) rate constants for paroxetine-induced block of Kv1.5 were 4.9 µM(-1)s(-1) and 16.1 s(-1), respectively. The theoretical K D value derived by k-1/k+1 yielded 3.3 µM. Paroxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of paroxetine, were superimposed. Inhibition of Kv1.5 by paroxetine was use-dependent. The present results suggest that paroxetine acts on Kv1.5 currents as an open-channel blocker.
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Affiliation(s)
- Hyang Mi Lee
- Department of Pharmacology, Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju 54097, Korea
| | - Sang June Hahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Bok Hee Choi
- Department of Pharmacology, Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju 54097, Korea
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20
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21
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Yang KC, Kyle JW, Makielski JC, Dudley SC. Mechanisms of sudden cardiac death: oxidants and metabolism. Circ Res 2015; 116:1937-55. [PMID: 26044249 PMCID: PMC4458707 DOI: 10.1161/circresaha.116.304691] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 02/09/2015] [Indexed: 02/07/2023]
Abstract
Ventricular arrhythmia is the leading cause of sudden cardiac death (SCD). Deranged cardiac metabolism and abnormal redox state during cardiac diseases foment arrhythmogenic substrates through direct or indirect modulation of cardiac ion channel/transporter function. This review presents current evidence on the mechanisms linking metabolic derangement and excessive oxidative stress to ion channel/transporter dysfunction that predisposes to ventricular arrhythmias and SCD. Because conventional antiarrhythmic agents aiming at ion channels have proven challenging to use, targeting arrhythmogenic metabolic changes and redox imbalance may provide novel therapeutics to treat or prevent life-threatening arrhythmias and SCD.
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Affiliation(s)
- Kai-Chien Yang
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.)
| | - John W Kyle
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.)
| | - Jonathan C Makielski
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.).
| | - Samuel C Dudley
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.).
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22
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Macías A, de la Cruz A, Prieto A, Peraza DA, Tamkun MM, González T, Valenzuela C. PKC inhibition results in a Kv 1.5 + Kv β1.3 pharmacology closer to Kv 1.5 channels. Br J Pharmacol 2014; 171:4914-26. [PMID: 24946104 DOI: 10.1111/bph.12822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 05/27/2014] [Accepted: 06/05/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE The Kv β1.3 subunit modifies the gating and pharmacology of Kv 1.5 channels in a PKC-dependent manner, decreasing channel sensitivity to bupivacaine- and quinidine-mediated blockade. Cardiac Kv 1.5 channels associate with receptor for activated C kinase 1 (RACK1), the Kv β1.3 subunit and different PKC isoforms, resulting in the formation of a functional channelosome. The aim of the present study was to investigate the effects of PKC inhibition on bupivacaine and quinidine block of Kv 1.5 + Kv β1.3 channels. EXPERIMENTAL APPROACH HEK293 cells were transfected with Kv 1.5 + Kv β1.3 channels, and currents were recorded using the whole-cell configuration of the patch-clamp technique. PKC inhibition was achieved by incubating the cells with either calphostin C or bisindolylmaleimide II and the effects of bupivacaine and quinidine were analysed. KEY RESULTS The voltage-dependent inactivation of Kv 1.5 + Kv β1.3 channels and their pharmacological behaviour after PKC inhibition with calphostin C were similar to those displayed by Kv 1.5 channels alone. Indeed, the IC50 values for bupivacaine were similar in cells whose PKC was inhibited with calphostin C or bisindolylmaleimide II. Similar results were also observed in the presence of quinidine. CONCLUSIONS AND IMPLICATIONS The finding that the voltage-dependence of inactivation and the pharmacology of Kv 1.5 + Kv β1.3 channels after PKC inhibition resembled that observed in Kv 1.5 channels suggests that both processes are dependent on PKC-mediated phosphorylation. These results may have clinical relevance in diseases that are characterized by alterations in kinase activity.
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Affiliation(s)
- A Macías
- Modelos Experimentales Enfermedades Humanas, Instituto de Investigaciones Biomédicas 'Alberto Sols' (CSIC-UAM), Madrid, Spain
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23
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Design, synthesis and evaluation of phenethylaminoheterocycles as Kv1.5 inhibitors. Bioorg Med Chem Lett 2014; 24:3018-22. [DOI: 10.1016/j.bmcl.2014.05.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 05/12/2014] [Indexed: 11/22/2022]
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24
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Yang KC, Bonini MG, Dudley SC. Mitochondria and arrhythmias. Free Radic Biol Med 2014; 71:351-361. [PMID: 24713422 PMCID: PMC4096785 DOI: 10.1016/j.freeradbiomed.2014.03.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/21/2014] [Accepted: 03/24/2014] [Indexed: 12/31/2022]
Abstract
Mitochondria are essential to providing ATP, thereby satisfying the energy demand of the incessant electrical activity and contractile action of cardiac muscle. Emerging evidence indicates that mitochondrial dysfunction can adversely affect cardiac electrical functioning by impairing the intracellular ion homeostasis and membrane excitability through reduced ATP production and excessive reactive oxygen species (ROS) generation, resulting in increased propensity to cardiac arrhythmias. In this review, the molecular mechanisms linking mitochondrial dysfunction to cardiac arrhythmias are discussed with an emphasis on the impact of increased mitochondrial ROS on the cardiac ion channels and transporters that are critical to maintaining normal electromechanical functioning of the cardiomyocytes. The potential of using mitochondria-targeted antioxidants as a novel antiarrhythmia therapy is highlighted.
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Affiliation(s)
- Kai-Chien Yang
- Lifespan Cardiovascular Institute, Providence VA Medical Center, and Brown University, Providence, RI 02903, USA
| | - Marcelo G Bonini
- Department of Medicine/Cardiology, University of Illinois at Chicago, Chicago, IL 60612, USA; Department of Pathology, and University of Illinois at Chicago, Chicago, IL 60612, USA; Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Samuel C Dudley
- Lifespan Cardiovascular Institute, Providence VA Medical Center, and Brown University, Providence, RI 02903, USA.
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Zhang YY, Li G, Che H, Sun HY, Li X, Au WK, Xiao GS, Wang Y, Li GR. Characterization of functional ion channels in human cardiac c-kit+ progenitor cells. Basic Res Cardiol 2014; 109:407. [DOI: 10.1007/s00395-014-0407-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 01/27/2014] [Accepted: 02/25/2014] [Indexed: 12/17/2022]
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Isoenzyme-specific regulation of cardiac Kv1.5/Kvβ1.2 ion channel complex by protein kinase C: central role of PKCβII. Naunyn Schmiedebergs Arch Pharmacol 2014; 387:469-76. [PMID: 24682423 DOI: 10.1007/s00210-014-0965-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 02/13/2014] [Indexed: 10/25/2022]
Abstract
The ultrarapidly activating delayed rectifier current, I(Kur), is a main determinant of atrial repolarization in humans. I(Kur) and the underlying ion channel complex Kv1.5/Kvβ1.2 are negatively regulated by protein kinase C. However, the exact mode of action is only incompletely understood. We therefore analyzed isoenzyme-specific regulation of the Kv1.5/Kvβ1.2 ion channel complex by PKC. Cloned ion channel subunits were heterologously expressed in Xenopus oocytes, and measurements were performed using the double-electrode voltage-clamp technique. Activation of PKC with phorbol 12-myristate 13-acetate (PMA) resulted in a strong reduction of Kv1.5/Kvβ1.2 current. This effect could be prevented using the PKC inhibitor staurosporine. Using the bisindolylmaleimide Ro-31-8220 as an inhibitor and ingenol as an activator of the conventional PKC isoforms, we were able to show that the Kv1.5/Kvβ1.2 ion channel complex is mainly regulated by conventional isoforms. Whereas pharmacological inhibition of PKCα with HBDDE did not attenuate the PMA-induced effect, current reduction could be prevented using inhibitors of PKCβ. Here, we show the isoform βII plays a central role in the PKC-dependent regulation of Kv1.5/Kvβ1.2 channels. These results add to the current understanding of isoenzyme-selective regulation of cardiac ion channels by protein kinases.
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Bondarenko VE. A compartmentalized mathematical model of the β1-adrenergic signaling system in mouse ventricular myocytes. PLoS One 2014; 9:e89113. [PMID: 24586529 PMCID: PMC3931689 DOI: 10.1371/journal.pone.0089113] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 01/14/2014] [Indexed: 01/08/2023] Open
Abstract
The β1-adrenergic signaling system plays an important role in the functioning of cardiac cells. Experimental data shows that the activation of this system produces inotropy, lusitropy, and chronotropy in the heart, such as increased magnitude and relaxation rates of [Ca2+]i transients and contraction force, and increased heart rhythm. However, excessive stimulation of β1-adrenergic receptors leads to heart dysfunction and heart failure. In this paper, a comprehensive, experimentally based mathematical model of the β1-adrenergic signaling system for mouse ventricular myocytes is developed, which includes major subcellular functional compartments (caveolae, extracaveolae, and cytosol). The model describes biochemical reactions that occur during stimulation of β1-adrenoceptors, changes in ionic currents, and modifications of Ca2+ handling system. Simulations describe the dynamics of major signaling molecules, such as cyclic AMP and protein kinase A, in different subcellular compartments; the effects of inhibition of phosphodiesterases on cAMP production; kinetics and magnitudes of phosphorylation of ion channels, transporters, and Ca2+ handling proteins; modifications of action potential shape and duration; magnitudes and relaxation rates of [Ca2+]i transients; changes in intracellular and transmembrane Ca2+ fluxes; and [Na+]i fluxes and dynamics. The model elucidates complex interactions of ionic currents upon activation of β1-adrenoceptors at different stimulation frequencies, which ultimately lead to a relatively modest increase in action potential duration and significant increase in [Ca2+]i transients. In particular, the model includes two subpopulations of the L-type Ca2+ channels, in caveolae and extracaveolae compartments, and their effects on the action potential and [Ca2+]i transients are investigated. The presented model can be used by researchers for the interpretation of experimental data and for the developments of mathematical models for other species or for pathological conditions.
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Affiliation(s)
- Vladimir E. Bondarenko
- Department of Mathematics and Statistics and Neuroscience Institute, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
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Lin YK, Chen YC, Huang JH, Lin YJ, Huang SS, Chen SA, Chen YJ. Leptin modulates electrophysiological characteristics and isoproterenol-induced arrhythmogenesis in atrial myocytes. J Biomed Sci 2013; 20:94. [PMID: 24354396 PMCID: PMC3878176 DOI: 10.1186/1423-0127-20-94] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/12/2013] [Indexed: 02/08/2023] Open
Abstract
Background Obesity is an important risk factor for atrial fibrillation (AF). Leptin is an important adipokine. However, it is not clear whether leptin directly modulates the electrophysiological characteristics of atrial myocytes. Results Whole cell patch clamp and indo-1 fluorescence were used to record the action potentials (APs) and ionic currents in isolated rabbit left atrial (LA) myocytes incubated with and without (control) leptin (100 nM) for 1 h to investigate the role of leptin on atrial electrophysiology. Leptin-treated LA myocytes (n = 19) had longer 20% of AP duration (28 ± 3 vs. 21 ± 2 ms, p < 0.05), but similar 50% of AP duration (51 ± 4 vs. 50 ± 3 ms, p > 0.05), and 90% of AP duration (89 ± 5 vs. 94 ± 4 ms, p > 0.05), as compared to the control (n = 22). In the presence of isoproterenol (10 nM), leptin-treated LA myocytes (n = 21) showed a lower incidence (19% vs. 54.2%, p < 0.05) of delayed afterdepolarization (DAD) than the control (n = 24). Leptin-treated LA myocytes showed a larger sodium current, but a smaller ultra-rapid delayed rectifier potassium current, and sodium-calcium exchanger current than the control. Leptin-treated and control LA myocytes exhibited a similar late sodium current, inward rectifier potassium current, transient outward current and L-type calcium current. In addition, the leptin-treated LA myocytes (n = 38) exhibited a smaller intracellular Ca2+ transient (0.21 ± 0.01 vs. 0.26 ± 0.01 R410/485, p < 0.05) and sarcoplasmic reticulum Ca2+ content (0.35 ± 0.02 vs. 0.43 ± 0.03 R410/485, p < 0.05) than the control LA myocytes (n = 42). Conclusions Leptin regulates the LA electrophysiological characteristics and attenuates isoproterenol-induced arrhythmogenesis.
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Affiliation(s)
| | | | | | | | | | | | - Yi-Jen Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, 111, Hsin-Lung Road, Sec, 3, Taipei, Taiwan.
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Heijman J, Dewenter M, El-Armouche A, Dobrev D. Function and regulation of serine/threonine phosphatases in the healthy and diseased heart. J Mol Cell Cardiol 2013; 64:90-8. [PMID: 24051368 DOI: 10.1016/j.yjmcc.2013.09.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 09/03/2013] [Accepted: 09/08/2013] [Indexed: 12/20/2022]
Abstract
Protein phosphorylation is a major control mechanism of a wide range of physiological processes and plays an important role in cardiac pathophysiology. Serine/threonine protein phosphatases control the dephosphorylation of a variety of cardiac proteins, thereby fine-tuning cardiac electrophysiology and function. Specificity of protein phosphatases type-1 and type-2A is achieved by multiprotein complexes that target the catalytic subunits to specific subcellular domains. Here, we describe the composition, regulation and target substrates of serine/threonine phosphatases in the heart. In addition, we provide an overview of pharmacological tools and genetic models to study the role of cardiac phosphatases. Finally, we review the role of protein phosphatases in the diseased heart, particularly in ventricular arrhythmias and atrial fibrillation and discuss their role as potential therapeutic targets.
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Affiliation(s)
- Jordi Heijman
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, 45122 Essen, Germany
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Li X, Wang T, Han K, Zhuo X, Lu Q, Ma A. Bisoprolol reverses down-regulation of potassium channel proteins in ventricular tissues of rabbits with heart failure. J Biomed Res 2013; 25:274-9. [PMID: 23554701 PMCID: PMC3597065 DOI: 10.1016/s1674-8301(11)60037-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 04/28/2011] [Accepted: 05/14/2011] [Indexed: 11/24/2022] Open
Abstract
Remodeling of ion channels is an important mechanism of arrhythmia induced by heart failure (HF). We investigated the expression of potassium channel encoding genes in the ventricles of rabbit established by volume-overload operation followed with pressure-overload. The reversible effect of these changes with bisoprolol was also evaluated. The HF group exhibited left ventricular enlargement, systolic dysfunction, prolongation of corrected QT interval (QTc), and increased plasma brain natriuretic peptide levels in the HF rabbits. Several potassium channel subunit encoding genes were consistently down-regulated in the HF rabbits. After bisoprolol treatment, heart function was improved significantly and QTc was shortened. Additionally, the mRNA expression of potassium channel subunit genes could be partially reversed. The down-regulated expression of potassium channel subunits Kv4.3, Kv1.4, KvLQT1, minK and Kir 2.1 may contribute to the prolongation of action potential duration in the heart of rabbits induced by volume combined with pressure overload HF. Bisoprolol could partially reverse these down-regulations and improve heart function.
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Affiliation(s)
- Xi Li
- Department of Cardiovascular Medicine, the First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
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Herring MJ, Oskui PM, Hale SL, Kloner RA. Testosterone and the cardiovascular system: a comprehensive review of the basic science literature. J Am Heart Assoc 2013; 2:e000271. [PMID: 23842280 PMCID: PMC3828782 DOI: 10.1161/jaha.113.000271] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Key Words] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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32
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Finlay HJ, Jiang J, Caringal Y, Kover A, Conder ML, Xing D, Levesque P, Harper T, Hsueh MM, Atwal K, Blanar M, Wexler R, Lloyd J. Triazolo and imidazo dihydropyrazolopyrimidine potassium channel antagonists. Bioorg Med Chem Lett 2013; 23:1743-7. [DOI: 10.1016/j.bmcl.2013.01.064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 01/10/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
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Abstract
Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation.
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Affiliation(s)
- Nitin T Aggarwal
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison, WI 53792, USA
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Bers DM, Grandi E. Human atrial fibrillation: insights from computational electrophysiological models. Trends Cardiovasc Med 2012; 21:145-50. [PMID: 22732550 DOI: 10.1016/j.tcm.2012.04.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 04/09/2012] [Accepted: 04/10/2012] [Indexed: 11/16/2022]
Abstract
Computational electrophysiology has proven useful to investigate the mechanisms of cardiac arrhythmias at various spatial scales, from isolated myocytes to the whole heart. This article reviews how mathematical modeling has aided our understanding of human atrial myocyte electrophysiology to study the contribution of structural and electrical remodeling to human atrial fibrillation. Potential new avenues of investigation and model development are suggested.
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Affiliation(s)
- Donald M Bers
- Department of Pharmacology, University of California at Davis, Davis, CA 95616-8636, USA.
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35
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González de la Fuente M, Barana A, Gómez R, Amorós I, Dolz-Gaitón P, Sacristán S, Atienza F, Pita A, Pinto Á, Fernández-Avilés F, Caballero R, Tamargo J, Delpón E. Chronic atrial fibrillation up-regulates β1-Adrenoceptors affecting repolarizing currents and action potential duration. Cardiovasc Res 2012; 97:379-88. [DOI: 10.1093/cvr/cvs313] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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David M, Macías Á, Moreno C, Prieto Á, Martínez-Mármol R, Vicente R, González T, Felipe A, Tamkun MM, Valenzuela C. Protein kinase C (PKC) activity regulates functional effects of Kvβ1.3 subunit on KV1.5 channels: identification of a cardiac Kv1.5 channelosome. J Biol Chem 2012; 287:21416-28. [PMID: 22547057 DOI: 10.1074/jbc.m111.328278] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
K(v)1.5 channels are the primary channels contributing to the ultrarapid outward potassium current (I(Kur)). The regulatory K(v)β1.3 subunit converts K(v)1.5 channels from delayed rectifiers with a modest degree of slow inactivation to channels with both fast and slow inactivation components. Previous studies have shown that inhibition of PKC with calphostin C abolishes the fast inactivation induced by K(v)β1.3. In this study, we investigated the mechanisms underlying this phenomenon using electrophysiological, biochemical, and confocal microscopy approaches. To achieve this, we used HEK293 cells (which lack K(v)β subunits) transiently cotransfected with K(v)1.5+K(v)β1.3 and also rat ventricular and atrial tissue to study native α-β subunit interactions. Immunocytochemistry assays demonstrated that these channel subunits colocalize in control conditions and after calphostin C treatment. Moreover, coimmunoprecipitation studies showed that K(v)1.5 and K(v)β1.3 remain associated after PKC inhibition. After knocking down all PKC isoforms by siRNA or inhibiting PKC with calphostin C, K(v)β1.3-induced fast inactivation at +60 mV was abolished. However, depolarization to +100 mV revealed K(v)β1.3-induced inactivation, indicating that PKC inhibition causes a dramatic positive shift of the inactivation curve. Our results demonstrate that calphostin C-mediated abolishment of fast inactivation is not due to the dissociation of K(v)1.5 and K(v)β1.3. Finally, immunoprecipitation and immunocytochemistry experiments revealed an association between K(v)1.5, K(v)β1.3, the receptor for activated C kinase (RACK1), PKCβI, PKCβII, and PKCθ in HEK293 cells. A very similar K(v)1.5 channelosome was found in rat ventricular tissue but not in atrial tissue.
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Affiliation(s)
- Miren David
- Instituto de Investigaciones Biomédicas, Madrid Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, C/Arturo Duperier 4, 28029 Madrid, Spain
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Grandi E, Workman AJ, Pandit SV. Altered Excitation-Contraction Coupling in Human Chronic Atrial Fibrillation. J Atr Fibrillation 2012; 4:495. [PMID: 28496736 DOI: 10.4022/jafib.495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 02/10/2012] [Accepted: 03/19/2012] [Indexed: 12/19/2022]
Abstract
This review focuses on the (mal)adaptive processes in atrial excitation-contraction coupling occurring in patients with chronic atrial fibrillation. Cellular remodeling includes shortening of the atrial action potential duration and effective refractory period, depressed intracellular Ca2+ transient, and reduced myocyte contractility. Here we summarize the current knowledge of the ionic bases underlying these changes. Understanding the molecular mechanisms of excitation-contraction-coupling remodeling in the fibrillating human atria is important to identify new potential targets for AF therapy.
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Affiliation(s)
- Eleonora Grandi
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Antony J Workman
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - Sandeep V Pandit
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, USA
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Jeong I, Choi BH, Yoon SH, Hahn SJ. Carvedilol blocks the cloned cardiac Kv1.5 channels in a β-adrenergic receptor-independent manner. Biochem Pharmacol 2012; 83:497-505. [PMID: 22146582 DOI: 10.1016/j.bcp.2011.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 11/21/2011] [Accepted: 11/21/2011] [Indexed: 10/14/2022]
Abstract
Carvedilol, a non-selective β-adrenergic blocker, is widely used for the treatment of angina pectoris and hypertension. We examined the action of carvedilol on cloned Kv1.5 expressed in CHO cells, using the whole-cell patch clamp technique. Carvedilol reduced the peak amplitude of Kv1.5 and accelerated the inactivation rate in a concentration-dependent manner with an IC50 of 2.56 μM. Using a first-order kinetics analysis, we calculated k(+1) = 19.68 μM(-1)s(-1) for the association rate constant, and k(-1) = 44.89 s(-1) for the dissociation rate constant. The apparent K(D) (k(-1)/k(+1)) was 2.28 μM, which is similar to the IC50 value. Other β-adrenergic blockers (alprenolol, oxprenolol and carteolol) had little or no effect on Kv1.5 currents. Carvedilol slowed the deactivation time course, resulting in a tail crossover phenomenon. Carvedilol-induced block was voltage-dependent in the voltage range for channel activation, but voltage-independent in the voltage range for full activation. The voltage dependences for both steady-state activation and inactivation were unchanged by carvedilol. Carvedilol affected Kv1.5 in a use-dependent manner. When stimulation frequencies were increased to quantify a use-dependent block, however, the block by carvedilol was slightly increased with IC50 values of 2.56 μM at 0.1 Hz, 2.38 μM at 1 Hz and 2.03 μM at 2 Hz. Carvedilol also slowed the time course of recovery from inactivation of Kv1.5. These results indicate that carvedilol blocks Kv1.5 in a reversible, concentration-, voltage-, time-, and use-dependent manner, but only at concentrations slightly higher than therapeutic plasma concentrations in humans. These effects are probably relevant to an understanding of the ionic mechanism underlying the antiarrhythmic property of carvedilol.
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Affiliation(s)
- Imju Jeong
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
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Remodelling of human atrial K+ currents but not ion channel expression by chronic β-blockade. Pflugers Arch 2011; 463:537-48. [PMID: 22160437 DOI: 10.1007/s00424-011-1061-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 11/11/2011] [Accepted: 11/14/2011] [Indexed: 10/14/2022]
Abstract
Chronic β-adrenoceptor antagonist (β-blocker) treatment in patients is associated with a potentially anti-arrhythmic prolongation of the atrial action potential duration (APD), which may involve remodelling of repolarising K(+) currents. The aim of this study was to investigate the effects of chronic β-blockade on transient outward, sustained and inward rectifier K(+) currents (I(TO), I(KSUS) and I(K1)) in human atrial myocytes and on the expression of underlying ion channel subunits. Ion currents were recorded from human right atrial isolated myocytes using the whole-cell-patch clamp technique. Tissue mRNA and protein levels were measured using real time RT-PCR and Western blotting. Chronic β-blockade was associated with a 41% reduction in I(TO) density: 9.3 ± 0.8 (30 myocytes, 15 patients) vs 15.7 ± 1.1 pA/pF (32, 14), p < 0.05; without affecting its voltage-, time- or rate dependence. I(K1) was reduced by 34% at -120 mV (p < 0.05). Neither I(KSUS), nor its increase by acute β-stimulation with isoprenaline, was affected by chronic β-blockade. Mathematical modelling suggested that the combination of I(TO)- and I(K1)-decrease could result in a 28% increase in APD(90). Chronic β-blockade did not alter mRNA or protein expression of the I(TO) pore-forming subunit, Kv4.3, or mRNA expression of the accessory subunits KChIP2, KChAP, Kvβ1, Kvβ2 or frequenin. There was no reduction in mRNA expression of Kir2.1 or TWIK to account for the reduction in I(K1). A reduction in atrial I(TO) and I(K1) associated with chronic β-blocker treatment in patients may contribute to the associated action potential prolongation, and this cannot be explained by a reduction in expression of associated ion channel subunits.
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Grandi E, Pandit SV, Voigt N, Workman AJ, Dobrev D, Jalife J, Bers DM. Human atrial action potential and Ca2+ model: sinus rhythm and chronic atrial fibrillation. Circ Res 2011; 109:1055-66. [PMID: 21921263 DOI: 10.1161/circresaha.111.253955] [Citation(s) in RCA: 252] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RATIONALE Understanding atrial fibrillation (AF) requires integrated understanding of ionic currents and Ca2+ transport in remodeled human atrium, but appropriate models are limited. OBJECTIVE To study AF, we developed a new human atrial action potential (AP) model, derived from atrial experimental results and our human ventricular myocyte model. METHODS AND RESULTS Atria versus ventricles have lower I(K1), resulting in more depolarized resting membrane potential (≈7 mV). We used higher I(to,fast) density in atrium, removed I(to,slow), and included an atrial-specific I(Kur). I(NCX) and I(NaK) densities were reduced in atrial versus ventricular myocytes according to experimental results. SERCA function was altered to reproduce human atrial myocyte Ca2+ transients. To simulate chronic AF, we reduced I(CaL), I(to), I(Kur) and SERCA, and increased I(K1),I(Ks) and I(NCX). We also investigated the link between Kv1.5 channelopathy, [Ca2+]i, and AF. The sinus rhythm model showed a typical human atrial AP morphology. Consistent with experiments, the model showed shorter APs and reduced AP duration shortening at increasing pacing frequencies in AF or when I(CaL) was partially blocked, suggesting a crucial role of Ca2+ and Na+ in this effect. This also explained blunted Ca2+ transient and rate-adaptation of [Ca2+]i and [Na+]i in chronic AF. Moreover, increasing [Na+]i and altered I(NaK) and I(NCX) causes rate-dependent atrial AP shortening. Blocking I(Kur) to mimic Kv1.5 loss-of-function increased [Ca2+]i and caused early afterdepolarizations under adrenergic stress, as observed experimentally. CONCLUSIONS Our study provides a novel tool and insights into ionic bases of atrioventricular AP differences, and shows how Na+ and Ca2+ homeostases critically mediate abnormal repolarization in AF.
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Affiliation(s)
- Eleonora Grandi
- Department of Pharmacology, University of California, Davis, 451 Health Sciences Dr, GBSF Room 3513, Davis, CA 95616-8636, USA
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Schotten U, Verheule S, Kirchhof P, Goette A. Pathophysiological mechanisms of atrial fibrillation: a translational appraisal. Physiol Rev 2011; 91:265-325. [PMID: 21248168 DOI: 10.1152/physrev.00031.2009] [Citation(s) in RCA: 852] [Impact Index Per Article: 65.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is an arrhythmia that can occur as the result of numerous different pathophysiological processes in the atria. Some aspects of the morphological and electrophysiological alterations promoting AF have been studied extensively in animal models. Atrial tachycardia or AF itself shortens atrial refractoriness and causes loss of atrial contractility. Aging, neurohumoral activation, and chronic atrial stretch due to structural heart disease activate a variety of signaling pathways leading to histological changes in the atria including myocyte hypertrophy, fibroblast proliferation, and complex alterations of the extracellular matrix including tissue fibrosis. These changes in electrical, contractile, and structural properties of the atria have been called "atrial remodeling." The resulting electrophysiological substrate is characterized by shortening of atrial refractoriness and reentrant wavelength or by local conduction heterogeneities caused by disruption of electrical interconnections between muscle bundles. Under these conditions, ectopic activity originating from the pulmonary veins or other sites is more likely to occur and to trigger longer episodes of AF. Many of these alterations also occur in patients with or at risk for AF, although the direct demonstration of these mechanisms is sometimes challenging. The diversity of etiological factors and electrophysiological mechanisms promoting AF in humans hampers the development of more effective therapy of AF. This review aims to give a translational overview on the biological basis of atrial remodeling and the proarrhythmic mechanisms involved in the fibrillation process. We pay attention to translation of pathophysiological insights gained from in vitro experiments and animal models to patients. Also, suggestions for future research objectives and therapeutical implications are discussed.
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Affiliation(s)
- Ulrich Schotten
- Department of Physiology, University Maastricht, Maastricht, The Netherlands.
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42
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Ravens U, Wettwer E. Ultra-rapid delayed rectifier channels: molecular basis and therapeutic implications. Cardiovasc Res 2010; 89:776-85. [DOI: 10.1093/cvr/cvq398] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Yang T, McBride BF, Leake BF, Kim RB, Roden DM. Modulation of drug block of the cardiac potassium channel KCNA5 by the drug transporters OCTN1 and MDR1. Br J Pharmacol 2010; 161:1023-33. [PMID: 20977453 DOI: 10.1111/j.1476-5381.2010.00932.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE A common site for drug binding on voltage-gated ion channels is at the interior face of the channel pore. In this study, we tested the hypothesis that the extent of drug block of the human cardiac KCNA5 (K(v) 1.5) channel underlying the atrial-specific, ultra-rapidly activating, delayed K(+) current (I(Kur) ) is modulated by the drug uptake and efflux transporters encoded by organic cation transporter 1 (OCTN1) and multiple drug-resistant gene 1 (MDR1) and expressed in human heart. EXPERIMENTAL APPROACH Drug block of KCNA5 was assessed in Chinese hamster ovary cells transiently transfected with KCNA5 alone or in combination with the OCTN1 or MDR1 transporter construct, as well as in an MDR1 stably expressed cell line. KEY RESULTS Co-expression of OCTN1 significantly facilitated block by quinidine (10 µM), verapamil (20 µM), propafenone (5 µM) and clofilium (30 µM). Further evidence of drug transport modulating drug block was the finding that with OCTN1, block developed faster and only partially washed-out, and that block potentiation was prevented by cimetidine, an inhibitor of OCTN1. MDR1 expression attenuated KCNA5 block by erythromycin (an MDR1 substrate). Block was restored by reversin-205 (10 µM, an MDR1 inhibitor). MDR1 did not affect KCNA5 inhibition by KN-93 (1 µM), a blocker acting on the outer mouth of the channel pore. CONCLUSIONS AND IMPLICATIONS The extent of drug block of KCNA5 can be modulated by drug uptake and efflux transporters. These data provide further support for the idea that modifying intracellular drug concentrations could modulate the effects of blocking ion channels in patients.
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Affiliation(s)
- Tao Yang
- Oates Institute for Experimental Therapeutics, Departments of Pharmacology and Medicine, University Medical Center, Vanderbilt University School of Medicine, 2215-B Garland Avenue, Nashville, TN 37232-0575, USA.
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Workman AJ. Cardiac adrenergic control and atrial fibrillation. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2010; 381:235-49. [PMID: 19960186 PMCID: PMC2855383 DOI: 10.1007/s00210-009-0474-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 11/08/2009] [Indexed: 10/20/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia, and it causes substantial mortality. The autonomic nervous system, and particularly the adrenergic/cholinergic balance, has a profound influence on the occurrence of AF. Adrenergic stimulation from catecholamines can cause AF in patients. In human atrium, catecholamines can affect each of the electrophysiological mechanisms of AF initiation and/or maintenance. Catecholamines may produce membrane potential oscillations characteristic of afterdepolarisations, by increasing Ca(2+) current, [Ca(2+)](i) and consequent Na(+)-Ca(2+) exchange, and may also enhance automaticity. Catecholamines might affect reentry, by altering excitability or conduction, rather than action potential terminal repolarisation or refractory period. However, which arrhythmia mechanisms predominate is unclear, and likely depends on cardiac pathology and adrenergic tone. Heart failure (HF), a major cause of AF, causes adrenergic activation and adaptational changes, remodelling, of atrial electrophysiology, Ca(2+) homeostasis, and adrenergic responses. Chronic AF also remodels these, but differently to HF. Myocardial infarction and AF cause neural remodelling that also may promote AF. beta-Adrenoceptor antagonists (beta-blockers) are used in the treatment of AF, mainly to control the ventricular rate, by slowing atrioventricular conduction. beta-Blockers also reduce the incidence of AF, particularly in HF or after cardiac surgery, when adrenergic tone is high. Furthermore, the chronic treatment of patients with beta-blockers remodels the atria, with a potentially antiarrhythmic increase in the refractory period. Therefore, the suppression of AF by beta-blocker treatment may involve an attenuation of arrhythmic activity that is caused by increased [Ca(2+)](i), coupled with effects of adaptation to the treatment. An improved understanding of the involvement of the adrenergic system and its control in basic mechanisms of AF under differing cardiac pathologies might lead to better treatments.
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Affiliation(s)
- Antony J Workman
- British Heart Foundation Glasgow Cardiovascular Research Centre, Division of Cardiovascular and Medical Sciences, Faculty of Medicine, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK.
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Li GR, Dong MQ. Pharmacology of Cardiac Potassium Channels. CARDIOVASCULAR PHARMACOLOGY - HEART AND CIRCULATION 2010; 59:93-134. [DOI: 10.1016/s1054-3589(10)59004-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
Papaverine, a vasodilator used as a therapeutic agent for a range of diseases, has been reported to increase the risk of occasional serious ventricular arrhythmias. To examine the mechanism for this effect, we herein tested the effects of papaverine on human ether-a-go-go (HERG) K channels expressed in HEK293 cells and Xenopus oocytes. Our results revealed that papaverine dose-dependently decreased the tail currents of HERG channel expressed in HEK293 cells with the IC50 and the Hill coefficient of 0.58 microM and 0.58, respectively, at +20 mV and 36 degrees C. The IC50 for the papaverine-induced blockade of HERG current in Xenopus oocytes was found to decrease progressively relative to depolarization (38.8, 30.0, and 24.8 microM at -10, +20, and +40 mV, respectively). The papaverine-induced blockade of HERG current was time-dependent; the fractional current was 0.92 +/- 0.03 of the control at the beginning of the pulse, but it declined to 0.18 +/- 0.06 after 6 seconds at a test potential of 0 mV. These results collectively indicate that papaverine blocks HERG channel in a concentration-, voltage-, and time-dependent manner. Two S6 domain mutations, Y652A and F656A, partially attenuated (Y652A) or abolished (F656A) the hERG current blockade, suggesting that papaverine blocks HERG channel at the pore of the channel. This was consistent with the computational simulation that showed papaverine interacts with Tyr652 and Phe656. Therefore, ventricular arrhythmias induced by papaverine could be resulted from the blockage of the HERG channel at the cardiac myocytes.
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Yang L, Ma JH, Zhang PH, Zou AR, Tu DN. QUERCETIN ACTIVATES HUMAN Kv1.5 CHANNELS BY A RESIDUE I502 IN THE S6 SEGMENT. Clin Exp Pharmacol Physiol 2009; 36:154-61. [DOI: 10.1111/j.1440-1681.2008.05061.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yang Q, Du L, Tsai KC, Wang X, Li M, You Q. Pharmacophore Mapping for Kv1.5 Potassium Channel Blockers. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/qsar.200810050] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Overholser BR, Zheng X, Tisdale JE. Catecholaminergic Effects on Ventricular Repolarization During Inhibition of the Rapid Component of the Delayed Rectifier Potassium Current in a Perfused Heart Model. Pharmacotherapy 2008; 28:1315-24. [DOI: 10.1592/phco.28.11.1315] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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