351
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Nakamura TY, Iwata Y, Arai Y, Komamura K, Wakabayashi S. Activation of Na+/H+ exchanger 1 is sufficient to generate Ca2+ signals that induce cardiac hypertrophy and heart failure. Circ Res 2008; 103:891-9. [PMID: 18776042 DOI: 10.1161/circresaha.108.175141] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Activation of the sarcolemmal Na(+)/H(+) exchanger (NHE)1 is increasingly documented as a process involved in cardiac hypertrophy and heart failure. However, whether NHE1 activation alone is sufficient to induce such remodeling remains unknown. We generated transgenic mice that overexpress a human NHE1 with high activity in hearts. The hearts of these mice developed cardiac hypertrophy, contractile dysfunction, and heart failure. In isolated transgenic myocytes, intracellular pH was elevated in Hepes buffer but not in physiological bicarbonate buffer, yet intracellular Na(+) concentrations were higher under both conditions. In addition, both diastolic and systolic Ca(2+) levels were increased as a consequence of Na(+)-induced Ca(2+) overload; this was accompanied by enhanced sarcoplasmic reticulum Ca(2+) loading via Ca(2+)/calmodulin-dependent protein kinase (CaMK)II-dependent phosphorylation of phospholamban. Negative force-frequency dependence was observed with preservation of high Ca(2+), suggesting a decrease in myofibril Ca(2+) sensitivity. Furthermore, the Ca(2+)-dependent prohypertrophic molecules calcineurin and CaMKII were highly activated in transgenic hearts. These effects observed in vivo and in vitro were largely prevented by the NHE1 inhibitor cariporide. Interestingly, overexpression of NHE1 in neonatal rat ventricular myocytes induced cariporide-sensitive nuclear translocation of NFAT (nuclear factor of activated T cells) and nuclear export of histone deacetylase 4, suggesting that increased Na(+)/H(+) exchange activity can alter hypertrophy-associated gene expression. However, in transgenic myocytes, contrary to exclusive translocation of histone deacetylase 4, NFAT only partially translocated to nucleus, possibly because of marked activation of p38, a negative regulator of NFAT signaling. We conclude that activation of NHE1 is sufficient to initiate cardiac hypertrophy and heart failure mainly through activation of CaMKII-histone deacetylase pathway.
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Affiliation(s)
- Tomoe Y Nakamura
- Department of Molecular Physiology, National Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan
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352
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Yano M, Yamamoto T, Kobayashi S, Ikeda Y, Matsuzaki M. Defective Ca2+ cycling as a key pathogenic mechanism of heart failure. Circ J 2008; 72 Suppl A:A22-30. [PMID: 18772523 DOI: 10.1253/circj.cj-08-0070] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Structural and functional alterations in the Ca(2+) regulatory proteins present in the sarcoplasmic reticulum (SR) have recently been shown to play a crucial role in the pathogenesis of heart failure (HF), and lethal arrhythmia as well. Chronic activation of the sympathetic nervous system induces abnormalities in both the function and structure of these proteins. For instance, the diastolic Ca(2+) leak through the SR Ca(2+) release channel (ryanodine receptor) reduces the SR Ca(2+) content, inducing contractile dysfunction. Moreover, the Ca(2+) leak provides a substrate for delayed after depolarization that leads to lethal arrhythmia. There is a considerable body of evidence regarding the role of Ca(2+) cycling abnormality in HF.
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Affiliation(s)
- Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan.
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353
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Hund TJ, Decker KF, Kanter E, Mohler PJ, Boyden PA, Schuessler RB, Yamada KA, Rudy Y. Role of activated CaMKII in abnormal calcium homeostasis and I(Na) remodeling after myocardial infarction: insights from mathematical modeling. J Mol Cell Cardiol 2008; 45:420-8. [PMID: 18639555 PMCID: PMC2587155 DOI: 10.1016/j.yjmcc.2008.06.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 06/13/2008] [Indexed: 10/21/2022]
Abstract
Ca(2+)/calmodulin-dependent protein kinase II is a multifunctional serine/threonine kinase with diverse cardiac roles including regulation of excitation contraction, transcription, and apoptosis. Dynamic regulation of CaMKII activity occurs in cardiac disease and is linked to specific disease phenotypes through its effects on ion channels, transporters, transcription and cell death pathways. Recent mathematical models of the cardiomyocyte have incorporated limited elements of CaMKII signaling to advance our understanding of how CaMKII regulates cardiac contractility and excitability. Given the importance of CaMKII in cardiac disease, it is imperative that computer models evolve to capture the dynamic range of CaMKII activity. In this study, using mathematical modeling combined with biochemical and imaging techniques, we test the hypothesis that CaMKII signaling in the canine infarct border zone (BZ) contributes to impaired calcium homeostasis and electrical remodeling. We report that the level of CaMKII autophosphorylation is significantly increased in the BZ region. Computer simulations using an updated mathematical model of CaMKII signaling reproduce abnormal Ca(2+) transients and action potentials characteristic of the BZ. Our simulations show that CaMKII hyperactivity contributes to abnormal Ca(2+) homeostasis and reduced action potential upstroke velocity due to effects on I(Na) gating kinetics. In conclusion, we present a new mathematical tool for studying effects of CaMKII signaling on cardiac excitability and contractility over a dynamic range of kinase activities. Our experimental and theoretical findings establish abnormal CaMKII signaling as an important component of remodeling in the canine BZ.
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Affiliation(s)
- Thomas J. Hund
- Department of Surgery Washington University in St. Louis St. Louis, MO
- Department of Internal Medicine University of Iowa Carver College of Medicine Iowa City, IA
| | - Keith F. Decker
- Department of Biomedical Engineering Washington University in St. Louis St. Louis, MO
- Cardiac Bioelectricity and Arrhythmia Center Washington University in St. Louis St. Louis, MO
| | - Evelyn Kanter
- Department of Medicine, Cardiovascular Division Washington University in St. Louis St. Louis, MO
| | - Peter J. Mohler
- Department of Internal Medicine University of Iowa Carver College of Medicine Iowa City, IA
| | - Penelope A. Boyden
- Department of Pharmacology, Center for Molecular Therapeutics Columbia University, New York, NY 10032
| | - Richard B. Schuessler
- Department of Surgery Washington University in St. Louis St. Louis, MO
- Cardiac Bioelectricity and Arrhythmia Center Washington University in St. Louis St. Louis, MO
| | - Kathryn A. Yamada
- Cardiac Bioelectricity and Arrhythmia Center Washington University in St. Louis St. Louis, MO
- Department of Medicine, Cardiovascular Division Washington University in St. Louis St. Louis, MO
- Center for Cardiovascular Research Washington University in St. Louis St. Louis, MO
| | - Yoram Rudy
- Department of Biomedical Engineering Washington University in St. Louis St. Louis, MO
- Cardiac Bioelectricity and Arrhythmia Center Washington University in St. Louis St. Louis, MO
- Department of Medicine, Cardiovascular Division Washington University in St. Louis St. Louis, MO
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354
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Calmodulin mediates differential sensitivity of CaMKII and calcineurin to local Ca2+ in cardiac myocytes. Biophys J 2008; 95:4597-612. [PMID: 18689454 DOI: 10.1529/biophysj.108.128728] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calmodulin (CaM) mediates Ca-dependent regulation of numerous pathways in the heart, including CaM-dependent kinase (CaMKII) and calcineurin (CaN), yet the local Ca(2+) signals responsible for their selective activation are unclear. To assess when and where CaM, CaMKII, and CaN may be activated in the cardiac myocyte, we integrated new mechanistic computational models of CaM, CaMKII, and CaN with the Shannon-Bers model of excitation-contraction coupling in the rabbit ventricular myocyte. These models are validated with independent in vitro data. In the intact myocyte, model simulations predict that CaM is highly activated in the dyadic cleft during each beat, but not appreciably in the cytosol. CaMKII-delta(C) was almost insensitive to cytosolic Ca due to relatively low CaM affinity. Dyadic cleft CaMKII exhibits dynamic frequency-dependent responses to Ca, yet autophosphorylates only when local phosphatases are suppressed. In contrast, dyadic cleft CaN in beating myocytes is predicted to be constitutively active, whereas the extremely high affinity of CaN for CaM allows gradual integration of small cytosolic CaM signals. Reversing CaM affinities for CaMKII and CaN also reverses their characteristic local responses. Deactivation of both CaMKII and CaN seems dominated by Ca dissociation from the complex (versus Ca-CaM dissociation from the target). In summary, the different affinities of CaM for CaMKII and CaN determine their sensitivity to local Ca signals in cardiac myocytes.
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355
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Abstract
Abnormal intracellular Ca(2+) handling by the sarcoplasmic reticulum (SR) is a critical factor in the development of heart failure (HF). Not only decreased Ca(2+) uptake, but also uncoordinated Ca(2+) release plays a significant role in contractile and relaxation dysfunction. Spontaneous Ca(2+) release through ryanodine receptor (RyR) 2, a huge tetrameric protein, during diastole leads to a decrease in the SR Ca(2+) content, and also triggers delayed after depolarization that is a substrate for lethal arrhythmia. Several disease-linked mutations of RyR have been reported in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) or arrhythmogenic right ventricular cardiomyopathy type 2 (ARVC2). The unique distribution of these mutation sites has lead to the concept that an interaction among the putative regulatory domains within RyR may play a key role in regulating channel opening, and that there seems to be a common abnormality in the channel disorder of HF and CPVT/ARVC2. Recent knowledge gained from pathological conditions may lead to the development of a new therapeutic strategy for the treatment of HF or cardiac arrhythmia.
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Affiliation(s)
- Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube 755-8505, Japan.
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356
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Györke S, Carnes C. Dysregulated sarcoplasmic reticulum calcium release: potential pharmacological target in cardiac disease. Pharmacol Ther 2008; 119:340-54. [PMID: 18675300 DOI: 10.1016/j.pharmthera.2008.06.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2008] [Accepted: 06/17/2008] [Indexed: 12/15/2022]
Abstract
In the heart, Ca(2+) released from the intracellular Ca(2+) storage site, the sarcoplasmic reticulum (SR), is the principal determinant of cardiac contractility. SR Ca(2+) release is controlled by dedicated molecular machinery, composed of the cardiac ryanodine receptor (RyR2) and a number of accessory proteins, including FKBP12.6, calsequestrin (CASQ2), triadin (TRD) and junctin (JN). Acquired and genetic defects in the components of the release channel complex result in a spectrum of abnormal Ca(2+) release phenotypes ranging from arrhythmogenic spontaneous Ca(2+) releases and Ca(2+) alternans to the uniformly diminished systolic Ca(2+) release characteristic of heart failure. In this article, we will present an overview of the structure and molecular components of the SR and Ca(2+) release machinery and its modulation by different intracellular factors, such as Ca(2+) levels inside the SR as well as phosphorylation and redox modification of RyR2s. We will also discuss the relationships between abnormal SR Ca(2+) release and various cardiac disease phenotypes, including, arrhythmias and heart failure, and consider SR Ca(2+) release as a potential therapeutic target.
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Affiliation(s)
- Sandor Györke
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, United States.
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357
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Wang Y, Tandan S, Cheng J, Yang C, Nguyen L, Sugianto J, Johnstone JL, Sun Y, Hill JA. Ca2+/calmodulin-dependent protein kinase II-dependent remodeling of Ca2+ current in pressure overload heart failure. J Biol Chem 2008; 283:25524-25532. [PMID: 18622016 DOI: 10.1074/jbc.m803043200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) activity is increased in heart failure (HF), a syndrome characterized by markedly increased risk of arrhythmia. Activation of CaMKII increases peak L-type Ca(2+) current (I(Ca)) and slows I(Ca) inactivation. Whether these events are linked mechanistically is unknown. I(Ca) was recorded in acutely dissociated subepicardial and subendocardial murine left ventricular (LV) myocytes using the whole cell patch clamp method. Pressure overload heart failure was induced by surgical constriction of the thoracic aorta. I(Ca) density was significantly larger in subepicardial myocytes than in subendocardial/myocytes. Similar patterns were observed in the cell surface expression of alpha1c, the channel pore-forming subunit. In failing LV, I(Ca) density was increased proportionately in both cell types, and the time course of I(Ca) inactivation was slowed. This typical pattern of changes suggested a role of CaMKII. Consistent with this, measurements of CaMKII activity revealed a 2-3-fold increase (p < 0.05) in failing LV. To test for a causal link, we measured frequency-dependent I(Ca) facilitation. In HF myocytes, this CaMKII-dependent process could not be induced, suggesting already maximal activation. Internal application of active CaMKII in failing myocytes did not elicit changes in I(Ca). Finally, CaMKII inhibition by internal diffusion of a specific peptide inhibitor reduced I(Ca) density and inactivation time course to similar levels in control and HF myocytes. I(Ca) density manifests a significant transmural gradient, and this gradient is preserved in heart failure. Activation of CaMKII, a known pro-arrhythmic molecule, is a major contributor to I(Ca) remodeling in load-induced heart failure.
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Affiliation(s)
- Yanggan Wang
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573
| | - Samvit Tandan
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573
| | - Jun Cheng
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573
| | - Chunmei Yang
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573
| | - Lan Nguyen
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573
| | - Jessica Sugianto
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573
| | - Janet L Johnstone
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573
| | - Yuyang Sun
- Department of Pediatrics, Emory University, Atlanta, Georgia 30322
| | - Joseph A Hill
- Department of Internal Medicine (Cardiology), Dallas, Texas 75390-8573; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8573 and the.
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358
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Hidalgo C, Donoso P. Crosstalk between calcium and redox signaling: from molecular mechanisms to health implications. Antioxid Redox Signal 2008; 10:1275-312. [PMID: 18377233 DOI: 10.1089/ars.2007.1886] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Studies done many years ago established unequivocally the key role of calcium as a universal second messenger. In contrast, the second messenger roles of reactive oxygen and nitrogen species have emerged only recently. Therefore, their contributions to physiological cell signaling pathways have not yet become universally accepted, and many biological researchers still regard them only as cellular noxious agents. Furthermore, it is becoming increasingly apparent that there are significant interactions between calcium and redox species, and that these interactions modify a variety of proteins that participate in signaling transduction pathways and in other fundamental cellular functions that determine cell life or death. This review article addresses first the central aspects of calcium and redox signaling pathways in animal cells, and continues with the molecular mechanisms that underlie crosstalk between calcium and redox signals under a number of physiological or pathological conditions. To conclude, the review focuses on conditions that, by promoting cellular oxidative stress, lead to the generation of abnormal calcium signals, and how this calcium imbalance may cause a variety of human diseases including, in particular, degenerative diseases of the central nervous system and cardiac pathologies.
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Affiliation(s)
- Cecilia Hidalgo
- Centro FONDAP de Estudios Moleculares de la Célula and Programa de Biología Molecular y Celular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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359
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Couchonnal LF, Anderson ME. The Role of Calmodulin Kinase II in Myocardial Physiology and Disease. Physiology (Bethesda) 2008; 23:151-9. [DOI: 10.1152/physiol.00043.2007] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) regulates a rich variety of downstream targets in heart. Ca2+ homeostatic proteins are important CaMKII targets that support myocardial excitation-contraction coupling. Under stress conditions, excessive CaMKII activity promotes heart failure and arrhythmias, in part through actions at Ca2+ homeostatic proteins. Here, we briefly review the molecular and cellular physiology of CaMKII in myocardium.
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Affiliation(s)
| | - Mark E. Anderson
- Departments of Internal Medicine and
- Molecular Physiology and Biophysics, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, Iowa,
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360
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A simulation study on the activation of cardiac CaMKII delta-isoform and its regulation by phosphatases. Biophys J 2008; 95:2139-49. [PMID: 18502812 DOI: 10.1529/biophysj.107.118505] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although the highly conserved Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is known to play an essential role in cardiac myocytes, its involvement in the frequency-dependent acceleration of relaxation is still controversial. To investigate the functional significance of CaMKII autophosphorylation and its regulation by protein phosphatases (PPs) in heart, we developed a new mathematical model for the CaMKIIdelta isoform. Due to better availability of experimental data, the model was first adjusted to the kinetics of the neuronal CaMKIIalpha isoform and then converted to a CaMKIIdelta model by fitting to kinetic data of the delta isoform. Both models satisfactorily reproduced experimental data of the CaMKII-calmodulin interaction, the autophosphorylation rate, and the frequency dependence of activation. The level of autophosphorylated CaMKII cumulatively increased upon starting the Ca(2+) stimulation at 3 Hz in the delta model. Variations in PP concentration remarkably affected the frequency-dependent activation of CaMKIIdelta, suggesting that cellular PP activity plays a key role in adjusting CaMKII activation in heart. The inhibitory effect of PP was stronger for CaMKIIalpha compared to CaMKIIdelta. Simulation results revealed a potential involvement of CaMKIIdelta autophosphorylation in the frequency-dependent acceleration of relaxation at physiological heart rates and PP concentrations.
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361
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Ge J, Sun A, Paajanen V, Wang S, Su C, Yang Z, Li Y, Wang S, Jia J, Wang K, Zou Y, Gao L, Wang K, Fan Z. Molecular and clinical characterization of a novel SCN5A mutation associated with atrioventricular block and dilated cardiomyopathy. Circ Arrhythm Electrophysiol 2008; 1:83-92. [PMID: 19808398 DOI: 10.1161/circep.107.750752] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Increased susceptibility to dilated cardiomyopathy has been observed in patients carrying mutations in the SCN5A gene, but the underlying mechanism remains unclear. In this study, we identified and characterized, both in vitro and clinically, an SCN5A mutation associated with familial progressive atrioventricular block of adult onset and dilated cardiomyopathy in a Chinese family. METHODS AND RESULTS Among 32 family members, 5 were initially diagnosed with atrioventricular block after age 30; 4 were studied, 3 of whom later developed dilated cardiomyopathy. We found a heterozygous single-nucleotide mutation resulting in an amino acid substitution (A1180V) in all studied patients and in 6 other younger unaffected members but not in 200 control chromosomes. When expressed with the beta1 subunit, the mutated channels exhibited a -4.5-mV shift of inactivation with slower recovery leading to a rate-dependent Na(+) current reduction and a moderate increase in late Na(+) current. Clinical study revealed that although QRS duration decreased with increasing heart rate in noncarrier family members, this change was blunted in unaffected carriers whose ECG and heart function were normal. Resting corrected QT interval of unaffected carriers was significantly longer than that of noncarriers, even though it was still within the normal range. CONCLUSIONS A1180V expresses a mild Na(+) channel phenotype in vitro and a corresponding clinical phenotype in unaffected mutation carriers, implying that A1180V caused structural heart disease in affected carriers by disturbing Na(+) influx and, hence, cellular Na(+) homeostasis. The high penetrance of A1180V suggests this phenotype as a high risk factor for dilated cardiomyopathy with preceding atrioventricular block.
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Affiliation(s)
- Junbo Ge
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China.
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362
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Ikeda Y, Hoshijima M, Chien KR. Toward biologically targeted therapy of calcium cycling defects in heart failure. Physiology (Bethesda) 2008; 23:6-16. [PMID: 18268360 DOI: 10.1152/physiol.00033.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A growing body of evidence indicates that heart failure progression is tightly associated with dysregulation of phosphorylation of Ca2+ regulators localized in the sub-cellular microdomain of the sarcoplasmic reticulum. Chemical or genetic correction of abnormalities in cardiac phosphorylation cascades is emerging as a potential target in the treatment of heart failure. Here, we review how specific kinases and phosphatases finely tune Ca2+ cycling and regulate excitation-contraction (E-C) coupling in cardiomyocytes.
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Affiliation(s)
- Yasuhiro Ikeda
- Department of Molecular Cardiovascular Biology, Yamaguchi University School of Medicine, Ube, Japan.
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363
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Abstract
Ventricular arrhythmias deteriorating into sudden cardiac death are a major cause of mortality worldwide. The recent linkage of a genetic form of cardiac arrhythmia to mutations in the gene encoding RyR2 (ryanodine receptor 2) has uncovered an important role of this SR (sarcoplasmic reticulum) calcium release channel in triggering arrhythmias. Mutant RyR2 channels give rise to spontaneous release of calcium (Ca(2+)) from the SR during diastole, which enhances the probability of ventricular arrhythmias. Several molecular mechanisms have been proposed to explain the gain-of-function phenotype observed in mutant RyR2 channels. Despite considerable differences between the models discussed in the present review, each predicts spontaneous diastolic Ca(2+) leak from the SR due to incomplete closure of the RyR2 channel. Enhanced SR Ca(2+) leak is also observed in common structural diseases of the heart, such as heart failure. In heart failure, defective channel regulation in the absence of inherited mutations may also increase SR Ca(2+) leak and initiate cardiac arrhythmias. Therefore inhibition of diastolic Ca(2+) leak through SR Ca(2+) release channels has emerged as a new and promising therapeutic target for cardiac arrhythmias.
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364
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Bossuyt J, Helmstadter K, Wu X, Clements-Jewery H, Haworth RS, Avkiran M, Martin JL, Pogwizd SM, Bers DM. Ca2+/calmodulin-dependent protein kinase IIdelta and protein kinase D overexpression reinforce the histone deacetylase 5 redistribution in heart failure. Circ Res 2008; 102:695-702. [PMID: 18218981 DOI: 10.1161/circresaha.107.169755] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac hypertrophy and heart failure (HF) are associated with reactivation of fetal cardiac genes, and class II histone deacetylases (HDACs) (eg, HDAC5) have been strongly implicated in this process. We have shown previously that inositol trisphosphate, Ca2+/calmodulin-dependent protein kinase II (CaMKII), and protein kinase (PK)D are involved in HDAC5 phosphorylation and nuclear export in normal adult ventricular myocytes and also that CaMKIIdelta and inositol trisphosphate receptors are upregulated in HF. Here we tested whether, in our rabbit HF model, nucleocytoplasmic shuttling of HDAC5 was altered either at baseline or in response to endothelin-1, which would indicate HDAC5 phosphorylation and transcription effects. The fusion protein HDAC5-green fluorescent protein (HDAC5-GFP) was more cytosolic in HF myocytes (F(nuc)/F(cyto) 3.3+/-0.3 vs 7.2+/-0.4 in control), and HDAC5 was more phosphorylated. Despite this baseline cytosolic HDAC5 shift, endothelin-1 produced more rapid HDAC5-GFP nuclear export in HF versus control myocytes. We also find that PKD and CaMKIIdelta(C) expression and activation state are increased in both rabbit and human HF. Inhibition of either CaMKII or PKD in HF myocytes partially restored the HDAC5-GFP F(nuc)/F(cyto) toward control, and simultaneous inhibition restored F(nuc)/F(cyto) to that in control myocytes. Moreover, adenovirus-mediated overexpression of PKD, CaMKIIdelta(B), or CaMKIIdelta(C) reduced baseline HDAC5 F(nuc)/F(cyto) in control myocytes (3.4+/-0.5, 3.8+/-0.5, and 5.2+/-0.5, respectively), approaching that seen in HF. We conclude that chronic upregulation and activation of inositol trisphosphate receptors, CaMKII, and PKD in HF shifts HDAC5 out of the nucleus, derepressing transcription of hypertrophic genes. This may directly contribute to the development and/or maintenance of HF.
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Affiliation(s)
- Julie Bossuyt
- Department of Physiology, Loyola University Chicago, Maywood, IL 60153, USA
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365
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Chang L, Zhang J, Tseng YH, Xie CQ, Ilany J, Brüning JC, Sun Z, Zhu X, Cui T, Youker KA, Yang Q, Day SM, Kahn CR, Chen YE. Rad GTPase deficiency leads to cardiac hypertrophy. Circulation 2007; 116:2976-2983. [PMID: 18056528 DOI: 10.1161/circulationaha.107.707257] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Rad (Ras associated with diabetes) GTPase is the prototypic member of a subfamily of Ras-related small G proteins. The aim of the present study was to define whether Rad plays an important role in mediating cardiac hypertrophy. METHODS AND RESULTS We document for the first time that levels of Rad mRNA and protein were decreased significantly in human failing hearts (n=10) compared with normal hearts (n=3; P<0.01). Similarly, Rad expression was decreased significantly in cardiac hypertrophy induced by pressure overload and in cultured cardiomyocytes with hypertrophy induced by 10 micromol/L phenylephrine. Gain and loss of Rad function in cardiomyocytes significantly inhibited and increased phenylephrine-induced hypertrophy, respectively. In addition, activation of calcium-calmodulin-dependent kinase II (CaMKII), a strong inducer of cardiac hypertrophy, was significantly inhibited by Rad overexpression. Conversely, downregulation of CaMKIIdelta by RNA interference technology attenuated the phenylephrine-induced hypertrophic response in cardiomyocytes in which Rad was also knocked down. To further elucidate the potential role of Rad in vivo, we generated Rad-deficient mice and demonstrated that they were more susceptible to cardiac hypertrophy associated with increased CaMKII phosphorylation than wild-type littermate controls. CONCLUSIONS The present data document for the first time that Rad is a novel mediator that inhibits cardiac hypertrophy through the CaMKII pathway. The present study will have significant implications for understanding the mechanisms of cardiac hypertrophy and setting the basis for the development of new strategies for treatment of cardiac hypertrophy.
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Affiliation(s)
- Lin Chang
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Jifeng Zhang
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Yu-Hua Tseng
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Chang-Qing Xie
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Jacob Ilany
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Jens C Brüning
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Zhongcui Sun
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Xiaojun Zhu
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Taixing Cui
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Keith A Youker
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Qinglin Yang
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Sharlene M Day
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - C Ronald Kahn
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
| | - Y Eugene Chen
- Cardiovascular Center (L.C., J.Z., C.-Q.X., T.C., S.M.D., Y.E.C.), Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Mich; Joslin Diabetes Center (Y.-H.T., J.I., J.C.B., C.R.K.), Harvard Medical School, Boston, Mass; Institute of Molecular Medicine (Z.S., X.Z.), Peking University, Beijing, People's Republic of China; Department of Cardiology (K.A.Y.), The Methodist Hospital Research Institute, Houston, Tex; and Cardiovascular Research Institute (Q.Y.), Morehouse School of Medicine, Atlanta, Ga
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366
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Sag CM, Dybkova N, Neef S, Maier LS. Effects on recovery during acidosis in cardiac myocytes overexpressing CaMKII. J Mol Cell Cardiol 2007; 43:696-709. [DOI: 10.1016/j.yjmcc.2007.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 09/07/2007] [Accepted: 09/20/2007] [Indexed: 10/22/2022]
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367
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Lu YM, Shioda N, Han F, Moriguchi S, Kasahara J, Shirasaki Y, Qin ZH, Fukunaga K. Imbalance between CaM kinase II and calcineurin activities impairs caffeine-induced calcium release in hypertrophic cardiomyocytes. Biochem Pharmacol 2007; 74:1727-37. [PMID: 17888407 DOI: 10.1016/j.bcp.2007.08.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2007] [Revised: 08/07/2007] [Accepted: 08/14/2007] [Indexed: 11/26/2022]
Abstract
Cardiac hypertrophy impairs Ca(2+) handling in the sarcoplasmic reticulum, thereby impairing cardiac contraction. To identify the mechanisms underlying impaired Ca(2+) release from the sarcoplasmic reticulum in hypertrophic cardiomyocytes, we assessed Ca(2+)-dependent signaling and the phosphorylation of phospholamban, which regulates Ca(2+) uptake during myocardial relaxation and is in turn regulated by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and calcineurin. In cultured rat cardiomyocytes, treatment with endothelin-1, angiotensin II, and phenylephrine-induced hypertrophy and increased CaMKII autophosphorylation and calcineurin expression. The calcineurin level reached its maximum at 72h and remained elevated for at least 96h after endothelin-1 or angiotensin II treatment. By contrast, CaMKII autophosphorylation, phospholamban phosphorylation, and caffeine-induced Ca(2+) mobilization all peaked 48h after these treatments. By 96h after treatment, CaMKII autophosphorylation and phospholamban phosphorylation had returned to baseline, and caffeine-induced Ca(2+) mobilization was impaired relative to baseline. A similar biphasic change was observed in dystrophin levels in endothelin-1-induced hypertrophic cardiomyocytes, and treatment with the novel CaM antagonists DY-9760e and DY-9836 significantly inhibited the hypertrophy-induced dystrophin breakdown. Taken together, the abnormal Ca(2+) regulation in cardiomyocytes following hypertrophy is in part mediated by an imbalance in calcineurin and CaMKII activities, which leads to abnormal phospholamban activity.
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Affiliation(s)
- Ying-Mei Lu
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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368
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369
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Calmodulin kinase II inhibition disrupts cardiomyopathic effects of enhanced green fluorescent protein. J Mol Cell Cardiol 2007; 44:405-10. [PMID: 18048055 DOI: 10.1016/j.yjmcc.2007.10.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2007] [Revised: 09/26/2007] [Accepted: 10/21/2007] [Indexed: 11/22/2022]
Abstract
Transgenic expression of enhanced green fluorescent protein (eGFP) in myocardium can result in cardiac dysfunction and cardiomyopathy, presumably through toxic effects that disrupt normal cellular signaling. The multifunctional Ca(2+)- and calmodulin-dependent protein kinase II (CaMKII) is widely expressed in myocardium and CaMKII activity is increased in human and animal models of cardiomyopathy, so we hypothesized that increased CaMKII activity is important for cardiomyopathy due to transgenic expression of eGFP. Here we report that cardiomyocyte-delimited eGFP over-expression causes increased CaMKII activity that predicts left ventricular dilation and dysfunction. On the other hand, transgenic co-expression of a CaMKII inhibitory peptide with eGFP prevents eGFP-mediated left ventricular dilation and dysfunction. These findings suggest that increased CaMKII activity is a critical pathological signal in transgenic cardiomyopathy due to eGFP over-expression.
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370
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Nakayama H, Chen X, Baines CP, Klevitsky R, Zhang X, Zhang H, Jaleel N, Chua BH, Hewett TE, Robbins J, Houser SR, Molkentin JD. Ca2+- and mitochondrial-dependent cardiomyocyte necrosis as a primary mediator of heart failure. J Clin Invest 2007; 117:2431-44. [PMID: 17694179 PMCID: PMC1937500 DOI: 10.1172/jci31060] [Citation(s) in RCA: 310] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2006] [Accepted: 05/14/2007] [Indexed: 01/08/2023] Open
Abstract
Loss of cardiac myocytes in heart failure is thought to occur largely through an apoptotic process. Here we show that heart failure can also be precipitated through myocyte necrosis associated with Ca2+ overload. Inducible transgenic mice with enhanced sarcolemmal L-type Ca2+ channel (LTCC) activity showed progressive myocyte necrosis that led to pump dysfunction and premature death, effects that were dramatically enhanced by acute stimulation of beta-adrenergic receptors. Enhanced Ca2+ influx-induced cellular necrosis and cardiomyopathy was prevented with either LTCC blockers or beta-adrenergic receptor antagonists, demonstrating a proximal relationship among beta-adrenergic receptor function, Ca2+ handling, and heart failure progression through necrotic cell loss. Mechanistically, loss of cyclophilin D, a regulator of the mitochondrial permeability transition pore that underpins necrosis, blocked Ca2+ influx-induced necrosis of myocytes, heart failure, and isoproterenol-induced premature death. In contrast, overexpression of the antiapoptotic factor Bcl-2 was ineffective in mitigating heart failure and death associated with excess Ca2+ influx and acute beta-adrenergic receptor stimulation. This paradigm of mitochondrial- and necrosis-dependent heart failure was also observed in other mouse models of disease, which supports the concept that heart failure is a pleiotropic disorder that involves not only apoptosis, but also necrotic loss of myocytes in association with dysregulated Ca2+ handling and beta-adrenergic receptor signaling.
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MESH Headings
- Adrenergic beta-2 Receptor Antagonists
- Animals
- Calcium/metabolism
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Cardiomyopathies/genetics
- Cardiomyopathies/metabolism
- Cardiomyopathies/pathology
- Cyclin D
- Cyclins/metabolism
- Disease Models, Animal
- Gene Expression Regulation
- Heart Failure/genetics
- Heart Failure/metabolism
- Heart Failure/pathology
- Heart Failure/prevention & control
- Mice
- Mice, Transgenic
- Mitochondria, Heart/metabolism
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Necrosis/genetics
- Necrosis/metabolism
- Necrosis/pathology
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Survival Rate
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Affiliation(s)
- Hiroyuki Nakayama
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Xiongwen Chen
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Christopher P. Baines
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Raisa Klevitsky
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Xiaoying Zhang
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Hongyu Zhang
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Naser Jaleel
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Balvin H.L. Chua
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Timothy E. Hewett
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Jeffrey Robbins
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Steven R. Houser
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
| | - Jeffery D. Molkentin
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
James H. Quillen School of Medicine, East Tennessee State University, and James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
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371
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Zhang T, Kohlhaas M, Backs J, Mishra S, Phillips W, Dybkova N, Chang S, Ling H, Bers DM, Maier LS, Olson EN, Brown JH. CaMKIIdelta isoforms differentially affect calcium handling but similarly regulate HDAC/MEF2 transcriptional responses. J Biol Chem 2007; 282:35078-87. [PMID: 17923476 DOI: 10.1074/jbc.m707083200] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The delta(B) and delta(C) splice variants of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), which differ by the presence of a nuclear localization sequence, are both expressed in cardiomyocytes. We used transgenic (TG) mice and CaMKII expression in cardiomyocytes to test the hypothesis that the CaMKIIdelta(C) isoform regulates cytosolic Ca(2+) handling and the delta(B) isoform, which localizes to the nucleus, regulates gene transcription. Phosphorylation of CaMKII sites on the ryanodine receptor (RyR) and on phospholamban (PLB) were increased in CaMKIIdelta(C) TG. This was associated with markedly enhanced sarcoplasmic reticulum (SR) Ca(2+) spark frequency and decreased SR Ca(2+) content in cardiomyocytes. None of these parameters were altered in TG mice expressing the nuclear-targeted CaMKIIdelta(B). In contrast, cardiac expression of either CaMKIIdelta(B) or delta(C) induced transactivation of myocyte enhancer factor 2 (MEF2) gene expression and up-regulated hypertrophic marker genes. Studies using rat ventricular cardiomyocytes confirmed that CaMKIIdelta(B) and delta(C) both regulate MEF2-luciferase gene expression, increase histone deacetylase 4 (HDAC4) association with 14-3-3, and induce HDAC4 translocation from nucleus to cytoplasm, indicating that either isoform can stimulate HDAC4 phosphorylation. Finally, HDAC4 kinase activity was shown to be increased in cardiac homogenates from either CaMKIIdelta(B) or delta(C) TG mice. Thus CaMKIIdelta isoforms have similar effects on hypertrophic gene expression but disparate effects on Ca(2+) handling, suggesting distinct roles for CaMKIIdelta isoform activation in the pathogenesis of cardiac hypertrophy versus heart failure.
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Affiliation(s)
- Tong Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0636, USA.
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372
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Grandi E, Puglisi JL, Wagner S, Maier LS, Severi S, Bers DM. Simulation of Ca-calmodulin-dependent protein kinase II on rabbit ventricular myocyte ion currents and action potentials. Biophys J 2007; 93:3835-47. [PMID: 17704163 PMCID: PMC2084250 DOI: 10.1529/biophysj.107.114868] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Ca-calmodulin-dependent protein kinase II (CaMKII) was recently shown to alter Na(+) channel gating and recapitulate a human Na(+) channel genetic mutation that causes an unusual combined arrhythmogenic phenotype in patients: simultaneous long QT syndrome and Brugada syndrome. CaMKII is upregulated in heart failure where arrhythmias are common, and CaMKII inhibition can reduce arrhythmias. Thus, CaMKII-dependent channel modulation may contribute to acquired arrhythmic disease. We developed a Markovian Na(+) channel model including CaMKII-dependent changes, and incorporated it into a comprehensive myocyte action potential (AP) model with Na(+) and Ca(2+) transport. CaMKII shifts Na(+) current (I(Na)) availability to more negative voltage, enhances intermediate inactivation, and slows recovery from inactivation (all loss-of-function effects), but also enhances late noninactivating I(Na) (gain of function). At slow heart rates, with long diastolic time for I(Na) recovery, late I(Na) is the predominant effect, leading to AP prolongation (long QT syndrome). At fast heart rates, where recovery time is limited and APs are shorter, there is little effect on AP duration, but reduced availability decreases I(Na), AP upstroke velocity, and conduction (Brugada syndrome). CaMKII also increases cardiac Ca(2+) and K(+) currents (I(Ca) and I(to)), complicating CaMKII-dependent AP changes. Incorporating I(Ca) and I(to) effects individually prolongs and shortens AP duration. Combining I(Na), I(Ca), and I(to) effects results in shortening of AP duration with CaMKII. With transmural heterogeneity of I(to) and I(to) downregulation in heart failure, CaMKII may accentuate dispersion of repolarization. This provides a useful initial framework to consider pathways by which CaMKII may contribute to arrhythmogenesis.
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Affiliation(s)
- Eleonora Grandi
- Biomedical Engineering Laboratory, Department of Electronics, Computer Science and Systems, University of Bologna, Bologna, Italy
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373
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McKinsey TA, Kass DA. Small-molecule therapies for cardiac hypertrophy: moving beneath the cell surface. Nat Rev Drug Discov 2007; 6:617-35. [PMID: 17643091 DOI: 10.1038/nrd2193] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pathological stress from cardiovascular disease stimulates hypertrophy of heart cells, which increases the risk of cardiac morbidity and mortality. Recent evidence has indicated that inhibiting such hypertrophy could be beneficial, encouraging drug discovery and development efforts for agents that could achieve this goal. Most existing therapies that have antihypertrophic effects target outside-in signalling in cardiac cells, but their effectiveness seems limited, and so attention has recently turned to the potential of targeting intracellular signalling pathways. Here, we focus on new developments with small-molecule inhibitors of cardiac hypertrophy, summarizing both agents that have been in or are poised for clinical testing, and pathways that offer further promising potential therapeutic targets.
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Affiliation(s)
- Timothy A McKinsey
- Gilead Colorado, Inc., 7575 West 103rd Avenue, Westminster, Colorado 80021, USA.
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374
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Pereira L, Métrich M, Fernández-Velasco M, Lucas A, Leroy J, Perrier R, Morel E, Fischmeister R, Richard S, Bénitah JP, Lezoualc'h F, Gómez AM. The cAMP binding protein Epac modulates Ca2+ sparks by a Ca2+/calmodulin kinase signalling pathway in rat cardiac myocytes. J Physiol 2007; 583:685-94. [PMID: 17599964 PMCID: PMC2277038 DOI: 10.1113/jphysiol.2007.133066] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
cAMP is a powerful second messenger whose known general effector is protein kinase A (PKA). The identification of a cAMP binding protein, Epac, raises the question of its role in Ca(2+) signalling in cardiac myocytes. In this study, we analysed the effects of Epac activation on Ca(2+) handling by using confocal microscopy in isolated adult rat cardiomyocytes. [Ca(2+)](i) transients were evoked by electrical stimulation and Ca(2+) sparks were measured in quiescent myocytes. Epac was selectively activated by the cAMP analogue 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (8-CPT). Patch-clamp was used to record the L-type calcium current (I(Ca)), and Western blot to evaluate phosphorylated ryanodine receptor (RyR). [Ca(2+)](i) transients were slightly reduced by 10 microm 8-CPT (F/F(0): decreased from 4.7 +/- 0.5 to 3.8 +/- 0.4, P < 0.05), an effect that was boosted when cells were previously infected with an adenovirus encoding human Epac. I(Ca) was unaltered by Epac activation, so this cannot explain the decreased [Ca(2+)](i) transients. Instead, a decrease in the sarcoplasmic reticulum (SR) Ca(2+) load underlies the decrease in the [Ca(2+)](i) transients. This decrease in the SR Ca(2+) load was provoked by the increase in the SR Ca(2+) leak induced by Epac activation. 8-CPT significantly increased Ca(2+) spark frequency (Ca(2+) sparks s(-1) (100 microm)(-1): from 2.4 +/- 0.6 to 6.9 +/- 1.5, P < 0.01) while reducing their amplitude (F/F(0): 1.8 +/- 0.02 versus 1.6 +/- 0.01, P < 0.001) in a Ca(2+)/calmodulin kinase II (CaMKII)-dependent and PKA-independent manner. Accordingly, we found that Epac increased RyR phosphorylation at the CaMKII site. Altogether, our data reveal a new signalling pathway by which cAMP governs Ca(2+) release and signalling in cardiac myocytes.
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Affiliation(s)
- Laetitia Pereira
- Inserm U637, Physiopathologie Cardiovasculaire, Montpellier, France
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375
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Ronkainen JJ, Vuolteenaho O, Tavi P. Calcium-calmodulin kinase II is the common factor in calcium-dependent cardiac expression and secretion of A- and B-type natriuretic peptides. Endocrinology 2007; 148:2815-20. [PMID: 17332063 DOI: 10.1210/en.2006-1676] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peptides derived from the precursor of A- and B-type natriuretic peptides (ANP and BNP) are powerful clinical markers of cardiac hypertrophy and dysfunction. It is known that many stimuli affecting the intracellular calcium concentration also induce ANP and BNP secretion. It was our intention to study the mechanisms by which calcium regulates the secretion of ANP and BNP. The effects of pacing and calcium-calmodulin kinase II activity on natriuretic peptide secretion were studied in isolated perfused rat atria and cultured rat neonatal cardiomyocytes. In isolated rat atrium pacing induced an increase in diastolic, systolic, and averaged intracellular free calcium concentration and a frequency-dependent increase in the secretion of both ANP and BNP. The molar ratio of the secreted natriuretic peptides (ANP to BNP) remained nearly constant ( approximately 1000) at all the pacing frequencies tested (1, 3, 6, and 8 Hz). Calmodulin kinase II inhibitor KN-93 (3 mum) did not affect intracellular free calcium concentration but showed a frequency-dependent inhibitory effect on ANP and BNP secretion without a change in ANP to BNP ratio. In the neonatal cardiomyocytes, KN-93 (3 mum) suppressed the secretion and gene expression of both ANP and BNP. Overexpression of constitutively active (T286D) or nuclear (delta(B)) calcium-calmodulin kinase II induced an increase in ANP and BNP gene expression. The results indicate that the calcium-dependent secretion and gene expression of A- and B-type natriuretic peptides are similarly regulated by calmodulin kinase II-dependent mechanisms. This is a plausible mechanism contributing to exercise-induced natriuretic peptide secretion and the augmented secretion in heart dysfunction due to impaired calcium handling.
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Affiliation(s)
- Jarkko J Ronkainen
- University of Oulu, Department of Physiology and Biocenter Oulu, University of Oulu, 90014 Oulu, Finland
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376
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MacQuaide N, Dempster J, Smith GL. Measurement and modeling of Ca2+ waves in isolated rabbit ventricular cardiomyocytes. Biophys J 2007; 93:2581-95. [PMID: 17545234 PMCID: PMC1965444 DOI: 10.1529/biophysj.106.102293] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The time course and magnitude of the Ca(2+) fluxes underlying spontaneous Ca(2+) waves in single permeabilized ventricular cardiomyocytes were derived from confocal Fluo-5F fluorescence signals. Peak flux rates via the sarcoplasmic reticulum (SR) release channel (RyR2) and the SR Ca(2+) ATPase (SERCA) were not constant across a range of cellular [Ca(2+)] values. The Ca(2+) affinity (K(mf)) and maximum turnover rate (V(max)) of SERCA and the peak permeability of the RyR2-mediated Ca(2+) release pathway increased at higher cellular [Ca(2+)] loads. This information was used to create a computational model of the Ca(2+) wave, which predicted the time course and frequency dependence of Ca(2+) waves over a range of cellular Ca(2+) loads. Incubation of cardiomyocytes with the Ca(2+) calmodulin (CaM) kinase inhibitor autocamtide-2-related inhibitory peptide (300 nM, 30 mins) significantly reduced the frequency of the Ca(2+) waves at high Ca(2+) loads. Analysis of the Ca(2+) fluxes suggests that inhibition of CaM kinase prevented the increases in SERCA V(max) and peak RyR2 release flux observed at high cellular [Ca(2+)]. These data support the view that modification of activity of SERCA and RyR2 via a CaM kinase sensitive process occurs at higher cellular Ca(2+) loads to increase the maximum frequency of spontaneous Ca(2+) waves.
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Affiliation(s)
- N MacQuaide
- Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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377
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Bers DM, Despa S, Bossuyt J. Regulation of Ca2+ and Na+ in normal and failing cardiac myocytes. Ann N Y Acad Sci 2007; 1080:165-77. [PMID: 17132783 DOI: 10.1196/annals.1380.015] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ca(2+) in cardiac myocytes regulates contractility and relaxation, and Ca(2+) and Na (+)regulation are linked via Na(+)/Ca(2+) exchange (NCX). Heart failure (HF) is accompanied by contractile dysfunction and arrhythmias, both of which may be due to altered cellular Ca(2+) handling. Smaller Ca(2+) transient and sarcoplasmic reticulum (SR) Ca(2+) content cause systolic dysfunction in HF. The reduced SR Ca(2+) content is due to: (a) reduced SR Ca(2+)-ATPase function (which also contributes to diastolic dysfunction), (b) increased expression and function of NCX (which competes with SR Ca(2+)-ATPase during relaxation, but preserves diastolic function), and (c) enhanced diastolic SR Ca(2+) leak. Relative contributions of these may vary with HF etiology and stage. Triggered arrhythmias (e.g., delayed afterdepolarizations [DADs]) are prominent in HF. DADs are due to spontaneous SR Ca(2+) release and consequent activation of transient inward NCX current, which in HF allows DADs to more readily trigger arrhythmogenic action potentials. Thus NCX and Na(+) are critical in systolic and diastolic function and arrhythmias. [Na(+)](i) is elevated in HF, which may limit SR unloading and provide some Ca(2+) influx during the HF action potential, thus limiting the depression of systolic function. High [Na(+)](i) in HF is due to enhanced Na(+) influx. Cellular Na(+)/K(+)-ATPase (NKA) function appears unaltered, despite reduced NKA expression. This dichotomy led us to test NKA regulation by phospholemman (PLM). We find that PLM regulates NKA in a manner analogous to phospholamban regulation of SR Ca(2+)-ATPase (i.e., inhibition that is relieved by PLM phosphorylation). We measured intermolecular FRET between PLM and NKA, which is reduced upon PLM phosphorylation. The lower expression level of more phosphorylated PLM in HF may explain the above dichotomy. Thus, altered Ca(2+) and Na(+) handling contributes to altered contractile function and arrhythmogenesis in HF.
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Affiliation(s)
- Donald M Bers
- Department of Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 South First Avenue, Maywood, IL 60153-5500, USA.
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378
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Yamaguchi N, Takahashi N, Xu L, Smithies O, Meissner G. Early cardiac hypertrophy in mice with impaired calmodulin regulation of cardiac muscle Ca release channel. J Clin Invest 2007; 117:1344-53. [PMID: 17431507 PMCID: PMC1847534 DOI: 10.1172/jci29515] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 02/13/2007] [Indexed: 11/17/2022] Open
Abstract
Studies with isolated membrane fractions have shown that calmodulin (CaM) inhibits the activity of cardiac muscle cell Ca(2+) release channel ryanodine receptor 2 (RyR2). To determine the physiological importance of CaM regulation of RyR2, we generated a mouse with 3 amino acid substitutions (RyR2-W3587A/L3591D/F3603A) in exon 75 of the Ryr2 gene, which encodes the CaM-binding site of RyR2. Homozygous mutant mice showed an increased ratio of heart weight to body weight, greatly reduced fractional shortening of the left ventricle, and lethality at 9-16 days of age. Biochemical analysis of hearts of 7- and 10-day-old homozygous mutant mice indicated an impaired CaM inhibition of RyR2 at micromolar Ca(2+) concentrations, reduction in RyR2 protein levels and sarcoplasmic reticulum Ca(2+) sequestration, and upregulation of genes and/or proteins associated with class II histone deacetylase/myocyte enhancer factor-2 and calcineurin signaling pathways. Sustained Ca(2+) transients, often displaying repeated periods of incomplete Ca(2+) removal, were observed in homozygous cardiomyocytes. Taken together, the data indicate that impaired CaM inhibition of RyR2, associated with defective sarcoplasmic reticulum Ca(2+) release and altered gene expression, leads to cardiac hypertrophy and early death.
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Affiliation(s)
- Naohiro Yamaguchi
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nobuyuki Takahashi
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Le Xu
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Oliver Smithies
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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379
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Zhu W, Woo AYH, Yang D, Cheng H, Crow MT, Xiao RP. Activation of CaMKIIδC Is a Common Intermediate of Diverse Death Stimuli-induced Heart Muscle Cell Apoptosis. J Biol Chem 2007; 282:10833-9. [PMID: 17296607 DOI: 10.1074/jbc.m611507200] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) is expressed in many mammalian cells, with the delta isoform predominantly expressed in cardiomyocytes. Previous studies have shown that inhibition of CaMKII protects cardiomyocytes against beta(1)-adrenergic receptor-mediated apoptosis. However, it is unclear whether activation of CaMKII is sufficient to cause cardiomyocyte apoptosis and whether CaMKII signaling is important in heart muscle cell apoptosis mediated by other stimuli. Here, we specifically enhanced or suppressed CaMKII activity using adenoviral gene transfer of constitutively active (CA-CaMKII(deltaC)) or dominant negative (DN-CaMKII(deltaC)) mutants of CaMKII(deltaC) in cultured adult rat cardiomyocytes. Expression of CA-CaMKII(deltaC) promoted cardiomyocyte apoptosis that was associated with increased mitochondrial cytochrome c release and attenuated by co-expression of Bcl-X(L). Importantly, isoform-specific suppression of CaMKII(deltaC) with the DN-CaMKII(deltaC) mutant similar to nonselective CaMKII inhibition by the pharmacological inhibitors (KN-93 or AIP) not only prevented CA-CaMKII(deltaC)-mediated apoptosis but also protected cells from multiple death-inducing stimuli. Thus, activation of CaMKII(deltaC) constitutes a common intermediate by which various death-inducing stimuli trigger cardiomyocyte apoptosis via the primary mitochondrial death pathway.
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Affiliation(s)
- Weizhong Zhu
- Laboratory of Cardiovascular Science, Gerontology Research Center, NIA, National Institutes of Health, Baltimore, Maryland 21224
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380
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Nattel S, Maguy A, Le Bouter S, Yeh YH. Arrhythmogenic Ion-Channel Remodeling in the Heart: Heart Failure, Myocardial Infarction, and Atrial Fibrillation. Physiol Rev 2007; 87:425-56. [PMID: 17429037 DOI: 10.1152/physrev.00014.2006] [Citation(s) in RCA: 597] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Rhythmic and effective cardiac contraction depends on appropriately timed generation and spread of cardiac electrical activity. The basic cellular unit of such activity is the action potential, which is shaped by specialized proteins (channels and transporters) that control the movement of ions across cardiac cell membranes in a highly regulated fashion. Cardiac disease modifies the operation of ion channels and transporters in a way that promotes the occurrence of cardiac rhythm disturbances, a process called “arrhythmogenic remodeling.” Arrhythmogenic remodeling involves alterations in ion channel and transporter expression, regulation and association with important protein partners, and has important pathophysiological implications that contribute in major ways to cardiac morbidity and mortality. We review the changes in ion channel and transporter properties associated with three important clinical and experimental paradigms: congestive heart failure, myocardial infarction, and atrial fibrillation. We pay particular attention to K+, Na+, and Ca2+channels; Ca2+transporters; connexins; and hyperpolarization-activated nonselective cation channels and discuss the mechanisms through which changes in ion handling processes lead to cardiac arrhythmias. We highlight areas of future investigation, as well as important opportunities for improved therapeutic approaches that are being opened by an improved understanding of the mechanisms of arrhythmogenic remodeling.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Quebec, Canada.
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381
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Yamaguchi N, Meissner G. Does Ca2+/calmodulin-dependent protein kinase deltac activate or inhibit the cardiac ryanodine receptor ion channel? Circ Res 2007; 100:293-5. [PMID: 17307966 DOI: 10.1161/01.res.0000259327.56377.55] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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382
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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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383
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Yurukova S, Kilić A, Völker K, Leineweber K, Dybkova N, Maier LS, Brodde OE, Kuhn M. CaMKII-mediated increased lusitropic responses to β-adrenoreceptor stimulation in ANP-receptor deficient mice. Cardiovasc Res 2007; 73:678-88. [PMID: 17107670 DOI: 10.1016/j.cardiores.2006.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 09/23/2006] [Accepted: 10/04/2006] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE Mice with genetic disruption of the guanylyl cyclase-A (GC-A) receptor for atrial natriuretic peptide (ANP), have chronic arterial hypertension and marked cardiac hypertrophy. Intriguingly, despite pronounced remodeling, cardiac contractile functions and cardiomyocyte Ca(2+)-handling are preserved and even enhanced. The present study aimed to characterize the specific molecular mechanisms preventing cardiac failure. METHODS AND RESULTS Contractile function and expression as well as phosphorylation of regulatory proteins were evaluated in isolated perfused working hearts from wild-type and GC-A KO mice under baseline conditions and during beta(1)-adrenergic stimulation. Ca(i)(2+)-transients were monitored in Indo-1 loaded isolated adult cardiomyocytes. Cardiac contractile, especially lusitropic responsiveness to beta-adrenergic stimulation was significantly increased in GC-A KO mice. This was concomitant to enhanced expression and activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), increased dual-site phosphorylation of phospholamban (PLB) at Ser(16) and Thr(17), enhanced amplitude of Ca(i)(2+) transients, and accelerated Ca(i)(2+) decay. In contrast, the expression of cardiac ryanodine receptors and phosphorylation at Ser(2809) and Ser(2815) was not altered. Pharmacological inhibition of CaMKII-but not of protein kinase A-mediated PLB phosphorylation totally abolished the increased effects of beta-adrenergic stimulation on cardiac contractility and Ca(i)(2+)-handling. Thus, acceleration of sarcoplasmic reticulum Ca(2+)-uptake and increased availability of Ca(2+) for contraction, both secondary to increased CaMKII-mediated PLB phosphorylation, seem to mediate the augmented responsiveness of GC-A KO hearts to catecholamines. CONCLUSION Our observations show that increased CaMKII activity enhances the contractile relaxation response of hypertrophic GC-A KO hearts to beta-adrenergic stimulation and emphasize the critical role of CaMKII-dependent pathways in beta(1)-adrenoreceptor modulation of myocardial Ca(2+)-homeostasis and contractility.
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Affiliation(s)
- Sevdalina Yurukova
- Institute of Physiology, University of Würzburg, Röntgenring 9, D-97070 Würzburg, Germany
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384
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Maier LS, Bers DM. Role of Ca2+/calmodulin-dependent protein kinase (CaMK) in excitation–contraction coupling in the heart. Cardiovasc Res 2007; 73:631-40. [PMID: 17157285 DOI: 10.1016/j.cardiores.2006.11.005] [Citation(s) in RCA: 244] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 11/03/2006] [Accepted: 11/06/2006] [Indexed: 11/27/2022] Open
Abstract
Calcium (Ca(2+)) is the central second messenger in the translation of electrical signals into mechanical activity of the heart. This highly coordinated process, termed excitation-contraction coupling or ECC, is based on Ca(2+)-induced Ca(2+) release from the sarcoplasmic reticulum (SR). In recent years it has become increasingly clear that several Ca(2+)-dependent proteins contribute to the fine tuning of ECC. One of these is the Ca(2+)/calmodulin-dependent protein kinase (CaMK) of which CaMKII is the predominant cardiac isoform. During ECC CaMKII phosphorylates several Ca(2+) handling proteins with multiple functional consequences. CaMKII may also be co-localized to distinct target proteins. CaMKII expression as well as activity are reported to be increased in heart failure and CaMKII overexpression can exert distinct and novel effects on ECC in the heart and in isolated myocytes of animals. In the present review we summarize important aspects of the role of CaMKII in ECC with an emphasis on recent novel findings.
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Affiliation(s)
- Lars S Maier
- Abt. Kardiologie & Pneumologie / Herzzentrum, Georg-August-Universität Göttingen, 37075 Göttingen, Germany.
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385
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Salazar NC, Chen J, Rockman HA. Cardiac GPCRs: GPCR signaling in healthy and failing hearts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1006-18. [PMID: 17376402 PMCID: PMC1892229 DOI: 10.1016/j.bbamem.2007.02.010] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2006] [Revised: 02/05/2007] [Accepted: 02/08/2007] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) are widely implicated in human heart disease, making them an important target for cardiac drug therapy. The most commonly studied and clinically targeted cardiac GPCRs include the adrenergic, angiotensin, endothelin, and adenosine receptors. Treatment options focusing on the complex and integrated signaling pathways of these GPCRs are critical for the understanding and amelioration of heart disease. The focus of this review is to highlight the most commonly studied and clinically targeted cardiac GPCRs, placing emphasis on their common signaling components implicated in cardiac disease.
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Affiliation(s)
- Natasha C Salazar
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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386
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Yang D, Zhu WZ, Xiao B, Brochet DXP, Chen SRW, Lakatta EG, Xiao RP, Cheng H. Ca
2+
/Calmodulin Kinase II-Dependent Phosphorylation of Ryanodine Receptors Suppresses Ca
2+
Sparks and Ca
2+
Waves in Cardiac Myocytes. Circ Res 2007; 100:399-407. [PMID: 17234969 DOI: 10.1161/01.res.0000258022.13090.55] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [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 δ
C
(CaMKIIδ
C
) is found in the macromolecular complex of type 2 ryanodine receptor (RyR2) Ca
2+
release channels in the heart. However, the functional role of CaMKII-dependent phosphorylation of RyR2 is highly controversial. To address this issue, we expressed wild-type, constitutively active, or dominant-negative CaMKIIδ
C
via adenoviral gene transfer in cultured adult rat ventricular myocytes. CaMKII-mediated phosphorylation of RyR2 was reduced, enhanced, or unaltered by dominant-negative, constitutively active, or wild-type CaMKIIδ
C
expression, whereas phosphorylation of phospholamban at Thr17, an endogenous indicator of CaMKII activity, was at 73%, 161%, or 115% of the control group expressing β-galactosidase (β-gal), respectively. In parallel with the phospholamban phosphorylation, the decay kinetics of global Ca
2+
transients was slowed, accelerated, or unchanged, whereas spontaneous Ca
2+
spark activity was hyperactive, depressed, or unchanged in dominant-negative, constitutively active, or wild-type CaMKIIδ
C
groups, respectively. When challenged by high extracellular Ca
2+
, both wild-type and constitutively active CaMKIIδ
C
protected the cells from store overload-induced Ca
2+
release, manifested by a ≈60% suppression of Ca
2+
waves (at 2 to 20 mmol/L extracellular Ca
2+
) in spite of an elevated sarcoplasmic reticulum Ca
2+
content, whereas dominant-negative CaMKIIδ
C
promoted Ca
2+
wave production (at 20 mmol/L Ca
2+
) with significantly depleted sarcoplasmic reticulum Ca
2+
. Taken together, our data support the notion that CaMKIIδ
C
negatively regulates RyR2 activity and spontaneous sarcoplasmic reticulum Ca
2+
release, thereby affording a negative feedback that stabilizes local and global Ca
2+
-induced Ca
2+
release in the heart.
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Affiliation(s)
- Dongmei Yang
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA
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387
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Abstract
Beta-adrenergic receptor activation plays an important role in the progression of human heart failure and the treatment of patients with beta-blockers has greatly improved the outcome of the disease. However, heart failure still is one of the leading causes of death in various countries and there is an imperative need for additional targets for the treatment of the disease. Recent studies by various groups have analyzed the downstream signaling pathways activated in response to beta-adrenergic stimulation that have the potential to become important targets for future treatments of heart failure. This review focuses on the significance of these pathways in the pathophysiology of heart failure in response to beta-adrenergic stimulation. More specifically the roles of PDE3, phosphorylation of phospholamban, and CaMKII activation are extensively discussed.
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Affiliation(s)
- Carmen C Sucharov
- Division of Cardiology, University of Colorado Health Sciences Center, 4200 E Ninth Ave, Denver, CO 80262, USA.
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388
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Picht E, DeSantiago J, Huke S, Kaetzel MA, Dedman JR, Bers DM. CaMKII inhibition targeted to the sarcoplasmic reticulum inhibits frequency-dependent acceleration of relaxation and Ca2+ current facilitation. J Mol Cell Cardiol 2007; 42:196-205. [PMID: 17052727 PMCID: PMC1828135 DOI: 10.1016/j.yjmcc.2006.09.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Accepted: 09/08/2006] [Indexed: 11/28/2022]
Abstract
Cardiac Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in heart has been implicated in Ca(2+) current (I(Ca)) facilitation, enhanced sarcoplasmic reticulum (SR) Ca(2+) release and frequency-dependent acceleration of relaxation (FDAR) via enhanced SR Ca(2+) uptake. However, questions remain about how CaMKII may work in these three processes. Here we tested the role of CaMKII in these processes using transgenic mice (SR-AIP) that express four concatenated repeats of the CaMKII inhibitory peptide AIP selectively in the SR membrane. Wild type mice (WT) and mice expressing AIP exclusively in the nucleus (NLS-AIP) served as controls. Increasing stimulation frequency produced typical FDAR in WT and NLS-AIP, but FDAR was markedly inhibited in SR-AIP. Quantitative analysis of cytosolic Ca(2+) removal during [Ca(2+)](i) decline revealed that FDAR is due to an increased apparent V(max) of SERCA. CaMKII-dependent RyR phosphorylation at Ser2815 and SR Ca(2+) leak was both decreased in SR-AIP vs. WT. This decrease in SR Ca(2+) leak may partly balance the reduced SERCA activity leading to relatively unaltered SR-Ca(2+) load in SR-AIP vs. WT myocytes. Surprisingly, CaMKII regulation of the L-type Ca(2+) channel (I(Ca) facilitation and recovery from inactivation) was abolished by the SR-targeted CaMKII inhibition in SR-AIP mice. Inhibition of CaMKII effects on I(Ca) and RyR function by the SR-localized AIP places physical constraints on the localization of these proteins at the junctional microdomain. Thus SR-targeted CaMKII inhibition can directly inhibit the activation of SR Ca(2+) uptake, SR Ca(2+) release and I(Ca) by CaMKII, effects which have all been implicated in triggered arrhythmias.
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Affiliation(s)
- Eckard Picht
- Department of Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA
| | - Jaime DeSantiago
- Department of Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA
| | - Sabine Huke
- Department of Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA
| | - Marcia A. Kaetzel
- Department of Genome Science, University of Cincinnati College of Medicine, 2180 E. Galbraith Road, Cincinnati, Ohio 45237, USA
| | - John R. Dedman
- Department of Genome Science, University of Cincinnati College of Medicine, 2180 E. Galbraith Road, Cincinnati, Ohio 45237, USA
| | - Donald M. Bers
- Department of Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA
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389
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Anderson ME, Higgins LS, Schulman H. Disease mechanisms and emerging therapies: protein kinases and their inhibitors in myocardial disease. ACTA ACUST UNITED AC 2006; 3:437-45. [PMID: 16874356 DOI: 10.1038/ncpcardio0585] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Accepted: 04/20/2006] [Indexed: 01/25/2023]
Abstract
Most clinically validated drugs for treating patients with cardiovascular disease target G-protein-coupled receptors (GPCRs) in the cell membrane. GPCRs engage and activate multiple intracellular signaling cascades, which are regulated by serine/threonine protein kinases. These protein kinases are cytoplasmic, more abundant than GPCRs, and have rapidly emerged as drug targets in cardiovascular diseases. One exciting potential advantage to targeting serine/threonine protein kinases rather than GPCRs is the capability of influencing more precisely the diverse biological responses that are initiated by a common GPCR. On the other hand, highly specific targeting of individual protein kinases for drug therapy presents some medicinal chemistry challenges. This concise review focuses on the biology of serine/threonine protein kinases in the cardiovascular system, discusses the current state of protein kinase inhibitor drug development for myocardial diseases, and illustrates some of the unique medicinal chemistry considerations in targeting protein kinases.
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Affiliation(s)
- Mark E Anderson
- Cardiovascular Research Center at the University of Iowa, Iowa City 52242-1081, USA.
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390
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Huke S, Bers DM. Temporal dissociation of frequency-dependent acceleration of relaxation and protein phosphorylation by CaMKII. J Mol Cell Cardiol 2006; 42:590-9. [PMID: 17239900 PMCID: PMC1857340 DOI: 10.1016/j.yjmcc.2006.12.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Revised: 11/07/2006] [Accepted: 12/13/2006] [Indexed: 11/20/2022]
Abstract
Frequency-dependent acceleration of relaxation (FDAR) is an important intrinsic mechanism that allows for diastolic filling of the ventricle at higher heart rates, yet its molecular mechanism is still not understood. Previous studies showed that FDAR is dependent on functional sarcoplasmic reticulum (SR) and can be abolished by phosphatase or by Ca/CaM kinase (CaMKII) inhibition. Additionally, CaMKII activity/autophosphorylation has been shown to be frequency-dependent. Thus, we tested the hypothesis that CaMKII phosphorylation of SR Ca(2+)-handling proteins (Phospholamban (PLB), Ca(2+) release channel (RyR)) mediates FDAR. Here we show that FDAR occurs abruptly in fluo-4 loaded isolated rat ventricular myocytes when frequency is raised from 0.1 to 2 Hz. The effect is essentially complete within four beats (2 s) with the tau of [Ca(2+)](i) decline decreasing by 42+/-3%. While there is a detectable increase in PLB Thr-17 and RyR Ser-2814 phosphorylation, the increase is quantitatively small (PLB<5%, RyR approximately 8%) and the time-course is clearly delayed with regard to FDAR. The low substrate phosphorylation indicates that pacing of myocytes only mildly activates CaMKII and consistent with this CaMKIIdelta autophosphorylation did not increase with pacing alone. However, in the presence of phosphatase 1 inhibition pacing triggered a net-increase in autophosphorylated CaMKII and also greatly enhanced PLB and RyR phosphorylation. We conclude that FDAR does not rely on phosphorylation of PLB or RyR. Even though CaMKII does become activated when myocytes are paced, phosphatases immediately antagonize CaMKII action, limit substrate phosphorylation and also prevent sustained CaMKII autophosphorylation (thereby suppressing global CaMKII effects).
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Affiliation(s)
- Sabine Huke
- Department of Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 South First Ave, Maywood, IL 60153-5500, USA
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391
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Little GH, Bai Y, Williams T, Poizat C. Nuclear calcium/calmodulin-dependent protein kinase IIdelta preferentially transmits signals to histone deacetylase 4 in cardiac cells. J Biol Chem 2006; 282:7219-31. [PMID: 17179159 DOI: 10.1074/jbc.m604281200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Class II histone deacetylases (HDACs) act as repressors of cardiac hypertrophy, an adaptative response of the heart characterized by a reprogramming of fetal cardiac genes. Prolonged hypertrophy often leads to dilated cardiomyopathy and heart failure. Upstream endogenous regulators of class II HDACs that regulate hypertrophic growth are just beginning to emerge. Here we demonstrate that the delta B isoform of calcium/calmodulin-dependent protein kinase II (CaMKIIdeltaB), known to promote cardiac hypertrophy, transmits signals specifically to HDAC4 but not other class II HDACs. CaMKIIdeltaB efficiently phosphorylates both a glutathione S-transferase (GST)-HDAC4 fragment spanning amino acids 207-311 and full-length FLAG-HDAC4 but not the equivalents in HDAC5. Although previous studies in skeletal muscle cells have shown that HDAC4 lacking serine 246 cannot be phosphorylated by CaMKI/IV, a similar mutant is still phosphorylated by CaMKIIdeltaB. Importantly, mutation of serine 210 to alanine totally abolishes phosphorylation of the GST fragment and significantly reduces phosphorylation of full-length HDAC by CaMKIIdeltaB. RNA interference knockdown of CaMKIIdeltaB prevents the effects of hypertrophic stimuli. Overexpression of CaMKIIdeltaB in primary neonatal cardiomyocytes increases the activity of the Mef2 transcription factor and completely rescues HDAC4-mediated repression of MEF2 but only partially rescues inhibition by HDAC5 or the HDAC4 S210A mutant. CaMKIIdeltaB strongly interacts with HDAC4 in cells but not with HDAC5. These results demonstrate that CaMKIIdeltaB preferentially targets HDAC4, and this involves serine 210. These findings identify HDAC4 as a specific downstream substrate of CaMKIIdeltaB in cardiac cells and have broad applications for the signaling pathways leading to cardiac hypertrophy and heart failure.
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Affiliation(s)
- Gillian H Little
- Institute for Genetic Medicine and Department of Biochemistry & Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
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392
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Vila-Petroff M, Salas MA, Said M, Valverde CA, Sapia L, Portiansky E, Hajjar RJ, Kranias EG, Mundiña-Weilenmann C, Mattiazzi A. CaMKII inhibition protects against necrosis and apoptosis in irreversible ischemia-reperfusion injury. Cardiovasc Res 2006; 73:689-98. [PMID: 17217936 DOI: 10.1016/j.cardiores.2006.12.003] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 11/14/2006] [Accepted: 12/04/2006] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVES Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) has been implicated in the regulation of cardiac excitation-contraction coupling (ECC) as well as in apoptotic signaling and adverse remodeling. The goal of the present study is to investigate the role of CaMKII in irreversible ischemia and reperfusion (I/R) injury. METHODS Isovolumic Langendorff perfused rat hearts were subjected to global no-flow I/R (45 min/120 min), and isolated myocytes were subjected to a protocol of simulated I/R (45 min simulated ischemia/60 min reoxygenation) either in the absence or presence of CaMKII inhibition [KN-93 (KN) or the CaMKII inhibitory peptide (AIP)]. RESULTS In I/R hearts, an increase in CaMKII activity at the beginning of reperfusion was confirmed by the significantly increased phosphorylation of the Thr(17) site of phospholamban. In the presence of KN, contractile recovery at the end of reperfusion was almost double that of I/R hearts. This recovery was associated with a significant decrease in the extent of infarction, lactate dehydrogenase release (necrosis), TUNEL-positive cells, caspase-3 activity, and an increase in the Bcl-2/Bax ratio (apoptosis). In isolated myocytes, both KN and AIP prevented simulated I/R-induced spontaneous contractile activity and cell mortality. Similar results were obtained when inhibiting the reverse mode Na(+)/Ca(2+) exchanger (NCX) with KB-R7943, sarcoplasmic reticulum (SR) function with ryanodine and thapsigargin, or SR Ca(2+) release with tetracaine. In contrast, overexpression of CaMKII decreased cell viability from 52+/-3% to 26+/-2%. CONCLUSIONS Taken together, the present findings are the first to establish CaMKII as a fundamental component of a cascade of events integrating the NCX, the SR, and mitochondria that promote cellular apoptosis and necrosis in irreversible I/R injury.
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Affiliation(s)
- Martin Vila-Petroff
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, 60 y 120, (1900) La Plata, Argentina
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393
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Oka T, Xu J, Molkentin JD. Re-employment of developmental transcription factors in adult heart disease. Semin Cell Dev Biol 2006; 18:117-31. [PMID: 17161634 PMCID: PMC1855184 DOI: 10.1016/j.semcdb.2006.11.012] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A finite number of transcription factors constitute a combinatorial code that orchestrates cardiac development and the specification and differentiation of myocytes. Many, if not all of these same transcription factors are re-employed in the adult heart in response to disease stimuli that promote hypertrophic enlargement and/or dilated cardiomyopathy, as part of the so-called "fetal gene program". This review will discuss the transcription factors that regulate the hypertrophic growth response of the adult heart, with a special emphasis on those regulators that participate in cardiac development.
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394
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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: 407] [Impact Index Per Article: 22.6] [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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395
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Grueter CE, Colbran RJ, Anderson ME. CaMKII, an emerging molecular driver for calcium homeostasis, arrhythmias, and cardiac dysfunction. J Mol Med (Berl) 2006; 85:5-14. [PMID: 17119905 DOI: 10.1007/s00109-006-0125-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 10/04/2006] [Accepted: 10/10/2006] [Indexed: 01/11/2023]
Abstract
Maintenance of cytoplasmic calcium homeostasis is critical for all cells. An exciting field has emerged in elucidating the multiple roles that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) plays in regulating Ca(2+) cycling in normal cardiac myocytes and in pathophysiological states. Moreover, CaMKII was recently identified as a potential drug target in cardiac disease. This work has given us a closer view of the complexity and therapeutic possibilities of CaMKII regulation of Ca(2+) signaling in cardiac myocytes.
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Affiliation(s)
- Chad E Grueter
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, USA
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396
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397
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Abstract
Sarcolemmal sodium (Na) and calcium (Ca) currents are fundamentally involved in shaping the cardiac action potential. Alterations in Na or Ca currents can change action potential characteristics and therefore might result in cardiac arrhythmias. Also, these ions contribute to excitation-contraction coupling and therefore are important in myocyte shortening and contractility of the heart. This review article summarizes how sarcolemmal Na and Ca channels are regulated with an emphasis on the novel role of Ca-dependent proteins Calmodulin (CaM) and especially Ca/CaM-dependent protein kinase II (CaMKII) to modulate sarcolemmal Na and Ca channels in the heart.
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Affiliation(s)
- Stefan Wagner
- Department of Cardiology and Pneumology/Heart Center Göttingen, Georg-August-University Göttingen, Germany
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398
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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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399
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Wu X, Bers DM. Free and bound intracellular calmodulin measurements in cardiac myocytes. Cell Calcium 2006; 41:353-64. [PMID: 16999996 PMCID: PMC1868497 DOI: 10.1016/j.ceca.2006.07.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 07/12/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
Calmodulin (CaM) is a ubiquitous Ca2+ binding protein and Ca2+-CaM activates many cellular targets and functions. While much of CaM is thought to be protein bound, quantitative data in cardiac myocytes is lacking regarding CaM location, [CaM]free and CaM redistribution during changes in [Ca2+]i. Here, we demonstrated that in adult rabbit cardiac myocytes, CaM is highly concentrated at Z-lines (confirmed by Di-8-ANEPPS staining of transverse tubules) using three different approaches: immunocytochemistry (endogenous CaM), Alexa Fluor 488 conjugate CaM (F-CaM) in both permeabilized cells (exogenous CaM) and in patch clamped intact cells (via pipette dialysis). Using 100 nM [CaM]free we washed F-CaM into permeabilized myocytes and saw a two-phase (fast and slow) CaM binding curve with a plateau after 40 min of F-CaM wash-in. We also measured myocyte [CaM]free using two modified null-point titration methods, finding [CaM]free to be 50-75 nM (which is only 1% of total [CaM]). Higher [Ca2+]i increased CaM binding especially in the nucleus and at Z-lines and significantly slowed F-CaM dissociation rate when F-CaM was washed out of permeabilized myocytes. Additionally, in both permeabilized and intact myocytes, CaM moved into the nucleus when [Ca2+]i was elevated, and this was reversible. We conclude that [CaM]free is very low in myocytes even at resting [Ca2+]i, indicating intense competition of CaM targets for free CaM. Bound CaM is relatively concentrated at Z-lines at rest but translocates significantly to the nucleus upon elevation of [Ca2+]i, which may influence activation of different targets and cellular functions.
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Affiliation(s)
- Xu Wu
- Department of Physiology, Loyola University Chicago, 2160 S First Ave., Maywood, IL 60153, United States
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400
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Abstract
Cardiac hypertrophy occurs in as many as 47% of normotensive individuals who chronically use cocaine. We investigated the effects of cocaine, in concentrations commonly found in chronic cocaine users, on calcium/calmodulin kinase (CaMK), and whether cocaine can activate CaMK, increase cardiac myocyte protein expression, and cause cardiac hypertrophy in this manner. In series I to III, 0 (control) or cocaine in concentrations of 10 to 10 mol/L was added to cultured adult rat cardiac ventricular myocytes to determine by Western blots and by P incorporation the optimal treatment time and the optimal dose for CaMK activation. In series I, cocaine, 10 mol/L, increased myocyte CaMKII translocation from myocyte soluble to particulate fractions by > or =73 +/- 9% (P < 0.01) in comparison with controls but did not cause the translocation of CaMKI or CaMKIV. In series II and III, cocaine treatment of myocytes for 15 minutes increased maximal CaMKII activity by 86.5 +/- 13.3% (P < 0.001) and a cocaine dose of 5 x 10 mol/L increased CaMKII activity by 169.5 +/- 18.1% (P < 0.001). In series IV we measured by silver staining beta-myosin heavy chain protein (beta-MHC) expression in myocytes before and after cocaine and also CaMK inhibition with KN-62 (1-[N,O-bis-(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine). In these experiments, cocaine, 5x10 mol/L, increased myocyte protein concentration by 29.2 +/- 2.8%, and beta-MHC by 93.2 +/- 8.8% (P < 0.001). In series V and VI, cocaine effects on calcium currents (ICa) and intracellular Ca ([Ca]i) were determined before and after CaMK inhibition with KN-62 in rat myocytes. Cocaine, 10 mol/L, enhanced ICa peak amplitude in a voltage-dependent manner (by 173.9 +/- 14.9% at -20 mV and by 38.4 +/- 6.9% at 0 mV P < 0.01). Cocaine, 10 to 10 mol/L, in series VI promoted Ca transients from myocyte sarcoplasmic reticulum and increased [Ca]i to 607 +/- 141 x 10 mol/L (P < 0.05). KN-62 decreased cocaine-induced myocyte protein expression by 76.6%, and beta-MHC by 66.2% (P < 0.01) and significantly decreased cocaine-induced Ca transients and [Ca]i. We conclude that CaMKII activation is an important mechanism whereby cocaine can cause myocyte hypertrophy.
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Affiliation(s)
- Robert J Henning
- Department of Medicine, University of South Florida College of Medicine and the James A. Haley VA Hospital, Tampa, Florida 33612, USA.
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