1
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CaMKII inhibition protects against hyperthyroid arrhythmias and adverse myocardial remodeling. Biochem Biophys Res Commun 2022; 615:136-142. [PMID: 35617800 DOI: 10.1016/j.bbrc.2022.04.082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/08/2022] [Accepted: 04/18/2022] [Indexed: 11/24/2022]
Abstract
Hyperthyroidism can potentiate arrhythmias and cardiac hypertrophy, whereas Ca2+/calmodulin-dependent kinase II (CaMKII) promotes maladaptive myocardial remodeling. However, it remains unclear whether CaMKII contributes to the progression of hyperthyroid heart disease (HHD). This study demonstrated that CaMKII inhibition can relieve adverse myocardial remodeling and reduce sinus tachycardia, isoproterenol-induced atrial fibrillation, and ventricular arrhythmias in hyperthyroid mice with preserved heart function. Hyperthyroid cardiac hypertrophy was promoted by CaMKII upregulation-induced HDAC4/MEF2a activation. Briefly, CaMKII inhibition benefits HHD management greatly in mice by preventing arrhythmias and maladaptive remodeling.
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2
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Zaitsev AV, Torres NS, Cawley KM, Sabry AD, Warren JS, Warren M. Conduction in the right and left ventricle is differentially regulated by protein kinases and phosphatases: implications for arrhythmogenesis. Am J Physiol Heart Circ Physiol 2019; 316:H1507-H1527. [PMID: 30875259 PMCID: PMC6620685 DOI: 10.1152/ajpheart.00660.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/19/2019] [Accepted: 03/07/2019] [Indexed: 12/19/2022]
Abstract
The "stress" kinases cAMP-dependent protein kinase (PKA) and calcium/calmodulin-dependent protein kinase II (CaMKII), phosphorylate the Na+ channel Nav1.5 subunit to regulate its function. However, how the channel regulation translates to ventricular conduction is poorly understood. We hypothesized that the stress kinases positively and differentially regulate conduction in the right (RV) and the left (LV) ventricles. We applied the CaMKII blocker KN93 (2.75 μM), PKA blocker H89 (10 μM), and broad-acting phosphatase blocker calyculin (30 nM) in rabbit hearts paced at a cycle length (CL) of 150-8,000 ms. We used optical mapping to determine the distribution of local conduction delays (inverse of conduction velocity). Control hearts exhibited constant and uniform conduction at all tested CLs. Calyculin (15-min perfusion) accelerated conduction, with greater effect in the RV (by 15.3%) than in the LV (by 4.1%; P < 0.05). In contrast, both KN93 and H89 slowed down conduction in a chamber-, time-, and CL-dependent manner, with the strongest effect in the RV outflow tract (RVOT). Combined KN93 and H89 synergistically promoted conduction slowing in the RV (KN93: 24.7%; H89: 29.9%; and KN93 + H89: 114.2%; P = 0.0016) but not the LV. The progressive depression of RV conduction led to conduction block and reentrant arrhythmias. Protein expression levels of both the CaMKII-δ isoform and the PKA catalytic subunit were higher in the RVOT than in the apical LV (P < 0.05). Thus normal RV conduction requires a proper balance between kinase and phosphatase activity. Dysregulation of this balance due to pharmacological interventions or disease is potentially proarrhythmic. NEW & NOTEWORTHY We show that uniform ventricular conduction requires a precise physiological balance of the activities of calcium/calmodulin-dependent protein kinase II (CaMKII), PKA, and phosphatases, which involves region-specific expression of CaMKII and PKA. Inhibiting CaMKII and/or PKA activity elicits nonuniform conduction depression, with the right ventricle becoming vulnerable to the development of conduction disturbances and ventricular fibrillation/ventricular tachycardia.
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Affiliation(s)
- Alexey V Zaitsev
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
- Department of Bioengineering, University of Utah , Salt Lake City, Utah
| | - Natalia S Torres
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
| | - Keiko M Cawley
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
| | - Amira D Sabry
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
| | - Junco S Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
- Department of Internal Medicine, School of Medicine, University of Utah , Salt Lake City, Utah
| | - Mark Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
- Department of Bioengineering, University of Utah , Salt Lake City, Utah
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3
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Monnerat G, Alarcón ML, Vasconcellos LR, Hochman-Mendez C, Brasil G, Bassani RA, Casis O, Malan D, Travassos LH, Sepúlveda M, Burgos JI, Vila-Petroff M, Dutra FF, Bozza MT, Paiva CN, Carvalho AB, Bonomo A, Fleischmann BK, de Carvalho ACC, Medei E. Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice. Nat Commun 2016; 7:13344. [PMID: 27882934 PMCID: PMC5123037 DOI: 10.1038/ncomms13344] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 09/24/2016] [Indexed: 02/08/2023] Open
Abstract
Diabetes mellitus (DM) encompasses a multitude of secondary disorders, including heart disease. One of the most frequent and potentially life threatening disorders of DM-induced heart disease is ventricular tachycardia (VT). Here we show that toll-like receptor 2 (TLR2) and NLRP3 inflammasome activation in cardiac macrophages mediate the production of IL-1β in DM mice. IL-1β causes prolongation of the action potential duration, induces a decrease in potassium current and an increase in calcium sparks in cardiomyocytes, which are changes that underlie arrhythmia propensity. IL-1β-induced spontaneous contractile events are associated with CaMKII oxidation and phosphorylation. We further show that DM-induced arrhythmias can be successfully treated by inhibiting the IL-1β axis with either IL-1 receptor antagonist or by inhibiting the NLRP3 inflammasome. Our results establish IL-1β as an inflammatory connection between metabolic dysfunction and arrhythmias in DM.
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MESH Headings
- Action Potentials
- Animals
- Antirheumatic Agents/pharmacology
- Arrhythmias, Cardiac/etiology
- Arrhythmias, Cardiac/immunology
- Arrhythmias, Cardiac/metabolism
- Calcium/metabolism
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Caspase 1/metabolism
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/immunology
- Diabetes Mellitus, Experimental/metabolism
- Inflammasomes/antagonists & inhibitors
- Interleukin 1 Receptor Antagonist Protein/pharmacology
- Interleukin-1beta/genetics
- Interleukin-1beta/immunology
- Interleukin-1beta/metabolism
- Macrophages/immunology
- Mice
- Mice, Transgenic
- Myocardial Contraction
- Myocytes, Cardiac/immunology
- Myocytes, Cardiac/metabolism
- NLR Family, Pyrin Domain-Containing 3 Protein/antagonists & inhibitors
- NLR Family, Pyrin Domain-Containing 3 Protein/genetics
- NLR Family, Pyrin Domain-Containing 3 Protein/immunology
- Potassium/metabolism
- Receptors, Interleukin-1/antagonists & inhibitors
- Receptors, Interleukin-1/genetics
- Receptors, Interleukin-1/immunology
- Tachycardia, Ventricular/etiology
- Tachycardia, Ventricular/immunology
- Tachycardia, Ventricular/metabolism
- Toll-Like Receptor 2/genetics
- Toll-Like Receptor 2/immunology
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Affiliation(s)
- Gustavo Monnerat
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Micaela L. Alarcón
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Luiz R. Vasconcellos
- LIRS-Laboratory of Immunoreceptors and Signaling, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Camila Hochman-Mendez
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Guilherme Brasil
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Rosana A. Bassani
- Center for Biomedical Engineering, University of Campinas, Campinas 13.083-970, Brazil
| | - Oscar Casis
- Departamento de Fisiología, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria, Spain
| | - Daniela Malan
- Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn D-53127, Germany
| | - Leonardo H. Travassos
- LIRS-Laboratory of Immunoreceptors and Signaling, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Marisa Sepúlveda
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Juan Ignacio Burgos
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Martin Vila-Petroff
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Fabiano F. Dutra
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Marcelo T. Bozza
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Claudia N. Paiva
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Adriana Bastos Carvalho
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Adriana Bonomo
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- FIOCANCER/ VPPLR/FIOCRUZ, FIOCRUZ-Manguinhos, Rio de Janeiro 21040-360, Brazil
| | - Bernd K. Fleischmann
- Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn D-53127, Germany
| | - Antonio Carlos Campos de Carvalho
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- National Center for Structural Biology and Bioimaging—CENABIO/UFRJ, Rio de Janeiro 21941-902, Brazil
| | - Emiliano Medei
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- National Center for Structural Biology and Bioimaging—CENABIO/UFRJ, Rio de Janeiro 21941-902, Brazil
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4
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Wu Y, Valdivia HH, Wehrens XHT, Anderson ME. A Single Protein Kinase A or Calmodulin Kinase II Site Does Not Control the Cardiac Pacemaker Ca2+ Clock. Circ Arrhythm Electrophysiol 2016; 9:e003180. [PMID: 26857906 DOI: 10.1161/circep.115.003180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Fight or flight heart rate (HR) increases depend on protein kinase A (PKA)- and calmodulin kinase II (CaMKII)-mediated enhancement of Ca(2+) uptake and release from sarcoplasmic reticulum (SR) in sinoatrial nodal cells (SANC). However, the impact of specific PKA and CaMKII phosphorylation sites on HR is unknown. METHODS AND RESULTS We systematically evaluated validated PKA and CaMKII target sites on phospholamban and the ryanodine receptor using genetically modified mice. We found that knockin alanine replacement of ryanodine receptor PKA (S2808) or CaMKII (S2814) target sites failed to affect HR responses to isoproterenol or spontaneous activity in vivo or in SANC. Similarly, selective mutation of phospholamban amino acids critical for enhancing SR Ca(2+) uptake by PKA (S16) or CaMKII (T17) to alanines did not affect HR in vivo or in SANC. In contrast, CaMKII inhibition by expression of AC3-I has been shown to slow SANC rate responses to isoproterenol and decrease SR Ca(2+) content. Phospholamban deficiency rescued SR Ca(2+) content and SANC rate responses to isoproterenol in mice with AC3-I expression, suggesting that CaMKII affects HR by modulation of SR Ca(2+) content. Consistent with this, mice expressing a superinhibitory phospholamban mutant had low SR Ca(2+) content and slow HR in vivo and in SANC. CONCLUSIONS SR Ca(2+) depletion reduces HR and SR Ca(2+) repletion restores physiological SANC rate responses, despite CaMKII inhibition. PKA and CaMKII do not affect HR by a unique target site governing SR Ca(2+) uptake or release. HR acceleration may require an SR Ca(2+) content threshold.
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Affiliation(s)
- Yuejin Wu
- From the Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD (Y.W., M.E.A.); Center for Arrhythmia Research, Cardiovascular Division, Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.); and Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, Medicine, Pediatrics, Baylor College of Medicine, Houston, TX (X.H.T.W.).
| | - Héctor H Valdivia
- From the Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD (Y.W., M.E.A.); Center for Arrhythmia Research, Cardiovascular Division, Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.); and Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, Medicine, Pediatrics, Baylor College of Medicine, Houston, TX (X.H.T.W.)
| | - Xander H T Wehrens
- From the Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD (Y.W., M.E.A.); Center for Arrhythmia Research, Cardiovascular Division, Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.); and Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, Medicine, Pediatrics, Baylor College of Medicine, Houston, TX (X.H.T.W.)
| | - Mark E Anderson
- From the Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD (Y.W., M.E.A.); Center for Arrhythmia Research, Cardiovascular Division, Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.); and Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, Medicine, Pediatrics, Baylor College of Medicine, Houston, TX (X.H.T.W.).
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5
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Chakraborty A, Pasek DA, Huang TQ, Gomez AC, Yamaguchi N, Anderson ME, Meissner G. Inhibition of CaMKII does not attenuate cardiac hypertrophy in mice with dysfunctional ryanodine receptor. PLoS One 2014; 9:e104338. [PMID: 25093823 PMCID: PMC4122402 DOI: 10.1371/journal.pone.0104338] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 07/12/2014] [Indexed: 02/07/2023] Open
Abstract
In cardiac muscle, the release of calcium ions from the sarcoplasmic reticulum through ryanodine receptor ion channels (RyR2s) leads to muscle contraction. RyR2 is negatively regulated by calmodulin (CaM) and by phosphorylation of Ca2+/CaM-dependent protein kinase II (CaMKII). Substitution of three amino acid residues in the CaM binding domain of RyR2 (RyR2-W3587A/L3591D/F3603A, RyR2ADA) impairs inhibition of RyR2 by CaM and results in cardiac hypertrophy and early death of mice carrying the RyR2ADA mutation. To test the cellular function of CaMKII in cardiac hypertrophy, mutant mice were crossed with mice expressing the CaMKII inhibitory AC3-I peptide or the control AC3-C peptide in the myocardium. Inhibition of CaMKII by AC3-I modestly reduced CaMKII-dependent phosphorylation of RyR2 at Ser-2815 and markedly reduced CaMKII-dependent phosphorylation of SERCA2a regulatory subunit phospholamban at Thr-17. However the average life span and heart-to-body weight ratio of Ryr2ADA/ADA mice expressing the inhibitory peptide were not altered compared to control mice. In Ryr2ADA/ADA homozygous mice, AC3-I did not alter cardiac morphology, enhance cardiac function, improve sarcoplasmic reticulum Ca2+ handling, or suppress the expression of genes implicated in cardiac remodeling. The results suggest that CaMKII was not required for the rapid development of cardiac hypertrophy in Ryr2ADA/ADA mice.
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Affiliation(s)
- Asima Chakraborty
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, United States of America
| | - Daniel A. Pasek
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, United States of America
| | - Tai-Qin Huang
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, United States of America
| | - Angela C. Gomez
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, United States of America
| | - Naohiro Yamaguchi
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, United States of America
| | - Mark E. Anderson
- Division of Cardiovascular Medicine, Departments of Internal Medicine, and Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, United States of America
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, United States of America
- * E-mail:
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6
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Ji Q, Liu H, Mei Y, Wang X, Feng J, Ding W. Expression changes of ionic channels in early phase of cultured rat atrial myocytes induced by rapid pacing. J Cardiothorac Surg 2013; 8:194. [PMID: 24074263 PMCID: PMC3851479 DOI: 10.1186/1749-8090-8-194] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 09/24/2013] [Indexed: 11/10/2022] Open
Abstract
Background Recent studies have demonstrated that atrial electrical remodeling was an important contributing factor for the occurrence, persistence and maintenance of atrial fibrillation. The expression changes of ionic channels, especially L-type calcium channel and potassium channel Kv4.3, were the important molecular mechanism of atrial electrical remodeling. This study aimed to observe the expression changes of ionic channels in a rapid paced cell model with primary cultured atrial myocytes. Methods The primary rat atrial myocytes were cultured, characteristics of the cultured myocytes were observed with light microscope and the cell phenotype was harvested by immunocytochemical stain to detect α-actin. The cellular model of rapid pacing was established with primary cultured atrial myocytes. The expressions of L-type calcium channel α1c and potassium channel Kv4.3 in cultured atrial myocytes were detected by immunocytochemistry, reverse transcription polymerase chain reaction and Western blot after rapid pacing. Results The primary rat atrial myocytes were isolated and cultured successfully, and used for following experiment by identification of activity and purity. Cellular model of rapid electrical field pacing was established successfully. There is no significant difference in cell activity after pacing compared to that before pacing by 3-[4, 5-dimethylthiazol-2-y1]-2, 5-diphenytetrazolium bromide assay, and cell degeneration can be observed by transmission electron microscope. The mRNA expression of L-type calcium channel α1c started to reduce after 6 h of rapid pacing and continued to decline as pacing continued. Protein expression changes were paralleled with decreased mRNA expression of the L-type calcium channel α1c. The mRNA expressions of potassium channel Kv4.3 were not altered within the first 6 h, but after 12 h, mRNA expressions were reduced. Longer pacing periods did not further decrease mRNA expression of potassium channel Kv4.3. Protein expression changes were paralleled with decreased mRNA expression of potassium channel Kv4.3. Conclusions Rapid paced cultured atrial myocyte model was established utilized primary cultured atrial myocytes and this model can be used for studying the early electrical remodeling in atrial fibrillation. Expressions of L-type calcium channel α1c and potassium channel Kv4.3 were both reduced at different levels in early phase of rapid pacing atrial myocytes. It implicates the occurrence of ionic channel remodeling of atrial myocytes.
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Affiliation(s)
- Qiang Ji
- Department of Thoracic Cardiovascular Surgery of Tongji Hospital of Tongji University Shanghai, 389 Xincun Rd, Shanghai 200065, P,R, China.
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7
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Yamanaka I, Miki M, Asakawa K, Kawakami K, Oda Y, Hirata H. Glycinergic transmission and postsynaptic activation of CaMKII are required for glycine receptor clusteringin vivo. Genes Cells 2013; 18:211-24. [DOI: 10.1111/gtc.12032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/29/2012] [Indexed: 02/06/2023]
Affiliation(s)
- Iori Yamanaka
- Division of Biological Science; Graduate School of Science; Nagoya University; Nagoya; 464-8602; Japan
| | - Mariko Miki
- Division of Biological Science; Graduate School of Science; Nagoya University; Nagoya; 464-8602; Japan
| | | | | | - Yoichi Oda
- Division of Biological Science; Graduate School of Science; Nagoya University; Nagoya; 464-8602; Japan
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8
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Ca2+/calmodulin-dependent protein kinase inhibition suppresses post-ischemic arrhythmogenesis and mediates sinus bradycardic recovery in reperfusion. Int J Cardiol 2012; 159:112-8. [DOI: 10.1016/j.ijcard.2011.02.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 01/10/2011] [Accepted: 02/10/2011] [Indexed: 11/20/2022]
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9
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Wang Y, Hill JA. Electrophysiological remodeling in heart failure. J Mol Cell Cardiol 2010; 48:619-32. [PMID: 20096285 DOI: 10.1016/j.yjmcc.2010.01.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 01/11/2010] [Accepted: 01/12/2010] [Indexed: 11/25/2022]
Abstract
Heart failure affects nearly 6 million Americans, with a half-million new cases emerging each year. Whereas up to 50% of heart failure patients die of arrhythmia, the diverse mechanisms underlying heart failure-associated arrhythmia are poorly understood. As a consequence, effectiveness of antiarrhythmic pharmacotherapy remains elusive. Here, we review recent advances in our understanding of heart failure-associated molecular events impacting the electrical function of the myocardium. We approach this from an anatomical standpoint, summarizing recent insights gleaned from pre-clinical models and discussing their relevance to human heart failure.
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Affiliation(s)
- Yanggan Wang
- Department of Pediatrics, Emory University, Atlanta, GA, USA.
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10
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Han FT, Kasirajan V, Kowalski M, Kiser R, Wolfe L, Kalahasty G, Shepard RK, Wood MA, Ellenbogen KA. Results of a Minimally Invasive Surgical Pulmonary Vein Isolation and Ganglionic Plexi Ablation for Atrial Fibrillation. Circ Arrhythm Electrophysiol 2009; 2:370-7. [DOI: 10.1161/circep.109.854828] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Frederick T. Han
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Vigneshwar Kasirajan
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Marcin Kowalski
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Robert Kiser
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Luke Wolfe
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Gautham Kalahasty
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Richard K. Shepard
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Mark A. Wood
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
| | - Kenneth A. Ellenbogen
- From the Department of Medicine (Cardiology) (F.T.H., M.K., R.K., G.K., R.K.S., M.A.W., K.A.E.) and Department of Medicine (Cardiac Surgery) (V.K., L.W.), Medical College of Virginia, Richmond, Va
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11
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Constitutive CaMKII activity regulates Na+ channel in rat ventricular myocytes. J Mol Cell Cardiol 2009; 47:475-84. [PMID: 19591836 DOI: 10.1016/j.yjmcc.2009.06.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 06/10/2009] [Accepted: 06/29/2009] [Indexed: 11/23/2022]
Abstract
The cardiac voltage-gated Na(+) channel controls the upstroke of action potential and membrane excitability. The Na(+) channel associates with Ca(2+)/CaM-dependent protein kinase (CaMKII), but the role of CaMKII on Na(+) channel activity in the resting state is not clear. In this report, we investigated whether CaMKII constitutively regulates Na(+) currents (I(Na)), independent of Ca(2+) influx in rat ventricular myocytes using patch clamp technique. CaMKII inhibition (by KN93 or autocamtide-related inhibitory peptide) caused a negative shift in I(Na) steady-state inactivation and delayed recovery from slow inactivation, limiting channel availability. The reduction of I(Na) was 29.47+/-3.01% at a holding potential (V(h)) of -120 mV and it increased to 77.70+/-7.92% when V(h) was -70 mV, suggesting that near the resting membrane potential, three-quarters of I(Na) depends on CaMKII action. CaMKII inhibition also enhanced intermediate inactivation, as well as delayed recovery from fast inactivation, and decreased late I(Na). KN92, an inactive analog of KN93, had no effect on I(Na). Using an antibody against phosphorylated (activated) CaMKII, we found that constitutively active CaMKII co-immunoprecipitated with Na(+) channels under resting conditions. CaMKII inhibitors reduced the level of phosphorylated CaMKII, which correlated with the degree of reduction in channel availability. These data suggest that CaMKII in an active form contributes to regulating I(Na). Finally, we observed a drastic reduction in the upstroke velocity of action potentials upon CaMKII inhibition. In conclusion, CaMKII constitutively regulates cardiac Na(+) channel and this regulatory mechanism is important for the maintenance of Na(+) channel characteristics under physiological conditions.
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12
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Abstract
Calcium/calmodulin-dependent kinase II (CaMKII) is a multifunctional serine/threonine kinase widely distributed in a number of tissue types. Activation of CaMKII has been linked to important downstream physiological processes, including apoptosis, hypertrophy, and arrhythmia in the heart. Pharmacological or genetic inhibition of CaMKII has been shown to improve health outcomes in a number of animal models. In this review, we summarize the structural and functional properties of CaMKII and detail its role in cardiac arrhythmia, structural heart disease, and sudden death.
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Affiliation(s)
- Jeffrey R Erickson
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109, USA
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13
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Said M, Becerra R, Palomeque J, Rinaldi G, Kaetzel MA, Diaz-Sylvester PL, Copello JA, Dedman JR, Mundiña-Weilenmann C, Vittone L, Mattiazzi A. Increased intracellular Ca2+ and SR Ca2+ load contribute to arrhythmias after acidosis in rat heart. Role of Ca2+/calmodulin-dependent protein kinase II. Am J Physiol Heart Circ Physiol 2008; 295:H1669-83. [PMID: 18723772 DOI: 10.1152/ajpheart.00010.2008] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Returning to normal pH after acidosis, similar to reperfusion after ischemia, is prone to arrhythmias. The type and mechanisms of these arrhythmias have never been explored and were the aim of the present work. Langendorff-perfused rat/mice hearts and rat-isolated myocytes were subjected to respiratory acidosis and then returned to normal pH. Monophasic action potentials and left ventricular developed pressure were recorded. The removal of acidosis provoked ectopic beats that were blunted by 1 muM of the CaMKII inhibitor KN-93, 1 muM thapsigargin, to inhibit sarcoplasmic reticulum (SR) Ca(2+) uptake, and 30 nM ryanodine or 45 muM dantrolene, to inhibit SR Ca(2+) release and were not observed in a transgenic mouse model with inhibition of CaMKII targeted to the SR. Acidosis increased the phosphorylation of Thr(17) site of phospholamban (PT-PLN) and SR Ca(2+) load. Both effects were precluded by KN-93. The return to normal pH was associated with an increase in SR Ca(2+) leak, when compared with that of control or with acidosis at the same SR Ca(2+) content. Ca(2+) leak occurred without changes in the phosphorylation of ryanodine receptors type 2 (RyR2) and was blunted by KN-93. Experiments in planar lipid bilayers confirmed the reversible inhibitory effect of acidosis on RyR2. Ectopic activity was triggered by membrane depolarizations (delayed afterdepolarizations), primarily occurring in epicardium and were prevented by KN-93. The results reveal that arrhythmias after acidosis are dependent on CaMKII activation and are associated with an increase in SR Ca(2+) load, which appears to be mainly due to the increase in PT-PLN.
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Affiliation(s)
- M Said
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina.
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Killeen MJ, Gurung IS, Thomas G, Stokoe KS, Grace AA, Huang CLH. Separation of early afterdepolarizations from arrhythmogenic substrate in the isolated perfused hypokalaemic murine heart through modifiers of calcium homeostasis. Acta Physiol (Oxf) 2007; 191:43-58. [PMID: 17524066 PMCID: PMC2040229 DOI: 10.1111/j.1748-1716.2007.01715.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS We resolved roles for early afterdepolarizations (EADs) and transmural gradients of repolarization in arrhythmogenesis in Langendorff-perfused hypokalaemic murine hearts paced from the right ventricular epicardium. METHODS Left ventricular epicardial and endocardial monophasic action potentials (MAPs) and arrhythmogenic tendency were compared in the presence and absence of the L-type Ca(2+) channel blocker nifedipine (10 nm-1 microm) and the calmodulin kinase type II inhibitor KN-93 (2 microm). RESULTS All the hypokalaemic hearts studied showed prolonged epicardial and endocardial MAPs, decreased epicardial-endocardial APD(90) difference, EADs, triggered beats and ventricular tachycardia (VT) (n = 6). In all spontaneously beating hearts, 100 (but not 10) nm nifedipine reduced both the incidence of EADs and triggered beats from 66.9 +/- 15.7% to 28.3 +/- 8.7% and episodes of VT from 10.8 +/- 6.3% to 1.2 +/- 0.7% of MAPs (n = 6 hearts, P < 0.05); 1 microm nifedipine abolished all these phenomena (n = 6). In contrast programmed electrical stimulation (PES) still triggered VT in six of six hearts with 0, 10 and 100 nm but not 1 microm nifedipine. 1 microm nifedipine selectively reduced epicardial (from 66.1 +/- 3.4 to 46.2 +/- 2.5 ms) but not endocardial APD(90), thereby restoring DeltaAPD(90) from -5.9 +/- 2.5 to 15.5 +/- 3.2 ms, close to normokalaemic values. KN-93 similarly reduced EADs, triggered beats and VT in spontaneously beating hearts to 29.6 +/- 8.9% and 1.7 +/- 1.1% respectively (n = 6) yet permitted PES-induced VT (n = 6), in the presence of a persistently negative DeltaAPD(90). CONCLUSIONS These findings empirically implicate both EADs and triggered beats alongside arrhythmogenic substrate of DeltaAPD(90) in VT pathogenesis at the whole heart level.
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Affiliation(s)
- M J Killeen
- Physiological Laboratory, University of Cambridge, Cambridge, UK.
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Anderson ME. Multiple downstream proarrhythmic targets for calmodulin kinase II: Moving beyond an ion channel-centric focus. Cardiovasc Res 2007; 73:657-66. [PMID: 17254559 DOI: 10.1016/j.cardiores.2006.12.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 12/08/2006] [Accepted: 12/11/2006] [Indexed: 11/21/2022] Open
Abstract
The multifunctional Ca(2+) calmodulin-dependent protein kinase II (CaMKII) has emerged as a pro-arrhythmic signaling molecule. CaMKII can participate in arrhythmia signaling by effects on ion channel proteins, intracellular Ca(2+) uptake and release, regulation of cell death, and by activation of hypertrophic signaling pathways. The pleuripotent nature of CaMKII is reminiscent of another serine-threonine kinase, protein kinase A (PKA), which shares many of the same protein targets and is the downstream kinase most associated with beta-adrenergic receptor stimulation. The ability of CaMKII to localize and coordinate activity of multiple protein targets linked to Ca(2+) signaling set CaMKII apart from other "traditional" arrhythmia drug targets, such as ion channel proteins. This review will discuss some of the biology of CaMKII and focus on work that has been done on molecular, cellular, and whole animal models that together build a case for CaMKII as a pro-arrhythmic signal and as a potential therapeutic target for arrhythmias and structural heart disease.
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Affiliation(s)
- Mark E Anderson
- University of Iowa, Carver College of Medicine, Department of Internal Medicine, 200 Hawkins Drive, E315-A1 GH, Iowa City, IA 52242 USA.
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Wagner S, Dybkova N, Rasenack EC, Jacobshagen C, Fabritz L, Kirchhof P, Maier SK, Zhang T, Hasenfuss G, Brown JH, Bers DM, Maier LS. Ca2+/calmodulin-dependent protein kinase II regulates cardiac Na+ channels. J Clin Invest 2006; 116:3127-38. [PMID: 17124532 PMCID: PMC1654201 DOI: 10.1172/jci26620] [Citation(s) in RCA: 400] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 10/03/2006] [Indexed: 01/01/2023] Open
Abstract
In heart failure (HF), Ca(2+)/calmodulin kinase II (CaMKII) expression is increased. Altered Na(+) channel gating is linked to and may promote ventricular tachyarrhythmias (VTs) in HF. Calmodulin regulates Na(+) channel gating, in part perhaps via CaMKII. We investigated effects of adenovirus-mediated (acute) and Tg (chronic) overexpression of cytosolic CaMKIIdelta(C) on Na(+) current (I(Na)) in rabbit and mouse ventricular myocytes, respectively (in whole-cell patch clamp). Both acute and chronic CaMKIIdelta(C) overexpression shifted voltage dependence of Na(+) channel availability by -6 mV (P < 0.05), and the shift was Ca(2+) dependent. CaMKII also enhanced intermediate inactivation and slowed recovery from inactivation (prevented by CaMKII inhibitors autocamtide 2-related inhibitory peptide [AIP] or KN93). CaMKIIdelta(C) markedly increased persistent (late) inward I(Na) and intracellular Na(+) concentration (as measured by the Na(+) indicator sodium-binding benzofuran isophthalate [SBFI]), which was prevented by CaMKII inhibition in the case of acute CaMKIIdelta(C) overexpression. CaMKII coimmunoprecipitates with and phosphorylates Na(+) channels. In vivo, transgenic CaMKIIdelta(C) overexpression prolonged QRS duration and repolarization (QT intervals), decreased effective refractory periods, and increased the propensity to develop VT. We conclude that CaMKII associates with and phosphorylates cardiac Na(+) channels. This alters I(Na) gating to reduce availability at high heart rate, while enhancing late I(Na) (which could prolong action potential duration). In mice, enhanced CaMKIIdelta(C) activity predisposed to VT. Thus, CaMKII-dependent regulation of Na(+) channel function may contribute to arrhythmogenesis in HF.
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Affiliation(s)
- Stefan Wagner
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Nataliya Dybkova
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Eva C.L. Rasenack
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Claudius Jacobshagen
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Larissa Fabritz
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Paulus Kirchhof
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Sebastian K.G. Maier
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Tong Zhang
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Joan Heller Brown
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Donald M. Bers
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Lars S. Maier
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
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Kumar R, Singh VP, Baker KM. Kinase inhibitors for cardiovascular disease. J Mol Cell Cardiol 2006; 42:1-11. [PMID: 17059822 DOI: 10.1016/j.yjmcc.2006.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 09/05/2006] [Accepted: 09/08/2006] [Indexed: 02/07/2023]
Abstract
Over the last decade, there has been substantial progress toward understanding the pathophysiology and treatment of cardiovascular diseases (CVDs). Elucidating cellular responses to the extracellular environment and signal transduction mechanisms have provided the opportunity to explore novel molecular therapeutic approaches for the treatment of CVDs. Neurohormonal stimulation has been implicated in these diseases; blockade of the renin-angiotensin and beta-adrenergic systems are examples of therapeutic effectiveness. There are multiple cell signaling cascades, some of which are beneficial or compensatory and others deleterious. The balance between these pathways, which in large part is dictated by the cellular environment, determines the outcome as a diseased or non-diseased state. Selective targeting of signaling pathways using protein kinase inhibitors, would have a potential advantage over receptor blockers. We review potential protein kinase targets and recent evidence supporting therapeutic interventional value in CVDs.
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Affiliation(s)
- Rajesh Kumar
- Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University System Health Science Center, College of Medicine, Temple, TX 76504, USA
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Li J, Marionneau C, Zhang R, Shah V, Hell JW, Nerbonne JM, Anderson ME. Calmodulin kinase II inhibition shortens action potential duration by upregulation of K+ currents. Circ Res 2006; 99:1092-9. [PMID: 17038644 DOI: 10.1161/01.res.0000249369.71709.5c] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The multifunctional Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is activated by elevated intracellular Ca(2+) (Ca(2+)(i)), and mice with chronic myocardial CaMKII inhibition (Inh) resulting from transgenic expression of a CaMKII inhibitory peptide (AC3-I) unexpectedly showed action potential duration (APD) shortening. Inh mice exhibit increased L-type Ca(2+) current (I(Ca)), because of upregulation of protein kinase A (PKA) activity, and decreased CaMKII-dependent phosphorylation of phospholamban (PLN). We hypothesized that CaMKII is a molecular signal linking Ca(2+)(i) to repolarization. Whole cell voltage-clamp recordings revealed that the fast transient outward current (I(to,f)) and the inward rectifier current (I(K1)) were selectively upregulated in Inh, compared with wild-type (WT) and transgenic control, mice. Breeding Inh mice with mice lacking PLN returned I(to,f) and I(K1) to control levels and equalized the APD and QT intervals in Inh mice to control and WT levels. Dialysis of AC3-I into WT cells did not result in increased I(to,f) or I(K1), suggesting that enhanced cardiac repolarization in Inh mice is an adaptive response to chronic CaMKII inhibition rather than an acute effect of reduced CaMKII activity. Increasing PKA activity, by cell dialysis with cAMP, or inhibition of PKA did not affect I(K1) in WT cells. Dialysis of WT cells with cAMP also reduced I(to,f), suggesting that PKA upregulation does not increase repolarizing K(+) currents in Inh mice. These findings provide novel in vivo and cellular evidence that CaMKII links Ca(2+)(i) to cardiac repolarization and suggest that PLN may be a critical CaMKII target for feedback regulation of APD in ventricular myocytes.
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Affiliation(s)
- Jingdong Li
- Department of Internal Medicine, University of Iowa, Carver College of Medicine, Iowa City, USA
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19
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Doggrell SA. Calmodulin kinase II as a target for inhibition in cardiac disease. Expert Opin Ther Targets 2005; 9:1319-21. [PMID: 16300478 DOI: 10.1517/14728222.9.6.1319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Sheila A Doggrell
- Division of Health Practice, Auckland University of Technology, Akoranga Campus, Northcote, Auckland, New Zealand.
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