51
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018. [PMID: 30425651 DOI: 10.3389/fphys.2018.01517, 10.3389/fpls.2018.01517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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52
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018; 9:1517. [PMID: 30425651 PMCID: PMC6218530 DOI: 10.3389/fphys.2018.01517] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/09/2018] [Indexed: 12/28/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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53
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018; 9:1517. [PMID: 30425651 PMCID: PMC6218530 DOI: 10.3389/fphys.2018.01517,+10.3389/fpls.2018.01517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States,*Correspondence: Dmitry Terentyev,
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54
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Bilginoglu A, Selcuk MFT, Nakkas H, Turan B. Pioglitazone provides beneficial effect in metabolic syndrome rats via affecting intracellular Na + Dyshomeostasis. J Bioenerg Biomembr 2018; 50:437-445. [PMID: 30361824 DOI: 10.1007/s10863-018-9776-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/17/2018] [Indexed: 02/06/2023]
Abstract
Metabolic syndrome, is associated impaired blood glucose level, insulin resistance, and dyslipidemia caused by abdominal obesity. Also, it is related with cardiovascular risk accumulation and cardiomyopathy. The hypothesis of this study was to examine the effect of thiazolidinediones such as pioglitazone on intracellular Na+ homeostasis in heart of metabolic syndrome male rats. Abdominal obesity and glucose intolerance had measured as a marker of metabolic syndrome. Intracellular Na+ concentration ([Na+]i) at rest and [Na+]i during pacing with electrical field stimulation were determined in freshly isolated cardiomyocytes. Also, TTX-sensitive Na+- channel current (INa) density and I-V characteristics of these channels were measured to understand [Na+]i homeostasis. We determined the protein levels of Na+/Ca2+ exchanger and Na+-K+ pump to understand the relation between [Na+]i homeostasis. High sucrose intake significantly increased body mass and blood glucose level of the rats in the metabolic syndrome group as compared with control group. There was a decrease in INa density and there were differences in points on activation curve of INa. Basal [Na+]i in metabolic syndrome group significantly increased but there was a significantly decrease in [Na+]i in stimulated cardiomyocytes in metabolic syndrome. Furthermore, pioglitazone induced decreases in the basal [Na+]i and preserved the decrease in INa and [Na+]i in stimulated cardiomyocytes to those of controls. Histologically, metabolic syndrome affected heart and associated tissues together with many other organs. Results of the present study suggest that pioglitazone has significant beneficial effects on metabolic syndrome associated disturbances in the heart via effecting Na+ homeostasis in cardiomyocytes.
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Affiliation(s)
- Ayca Bilginoglu
- Department of Biophysics, Faculty of Medicine, Ankara Yıldırım Beyazıt University, Ankara, Turkey.
| | | | - Hilal Nakkas
- Department of Histology and Embriyology, Faculty of Medicine, Ankara Yıldırım Beyazıt University, Ankara, Turkey
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
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55
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Doliba NM, Babsky AM, Osbakken MD. The Role of Sodium in Diabetic Cardiomyopathy. Front Physiol 2018; 9:1473. [PMID: 30405433 PMCID: PMC6207851 DOI: 10.3389/fphys.2018.01473] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/28/2018] [Indexed: 12/11/2022] Open
Abstract
Cardiovascular complications are the major cause of mortality and morbidity in diabetic patients. The changes in myocardial structure and function associated with diabetes are collectively called diabetic cardiomyopathy. Numerous molecular mechanisms have been proposed that could contribute to the development of diabetic cardiomyopathy and have been studied in various animal models of type 1 or type 2 diabetes. The current review focuses on the role of sodium (Na+) in diabetic cardiomyopathy and provides unique data on the linkage between Na+ flux and energy metabolism, studied with non-invasive 23Na, and 31P-NMR spectroscopy, polarography, and mass spectroscopy. 23Na NMR studies allow determination of the intracellular and extracellular Na+ pools by splitting the total Na+ peak into two resonances after the addition of a shift reagent to the perfusate. Using this technology, we found that intracellular Na+ is approximately two times higher in diabetic cardiomyocytes than in control possibly due to combined changes in the activity of Na+–K+ pump, Na+/H+ exchanger 1 (NHE1) and Na+-glucose cotransporter. We hypothesized that the increase in Na+ activates the mitochondrial membrane Na+/Ca2+ exchanger, which leads to a loss of intramitochondrial Ca2+, with a subsequent alteration in mitochondrial bioenergetics and function. Using isolated mitochondria, we showed that the addition of Na+ (1–10 mM) led to a dose-dependent decrease in oxidative phosphorylation and that this effect was reversed by providing extramitochondrial Ca2+ or by inhibiting the mitochondrial Na+/Ca2+ exchanger with diltiazem. Similar experiments with 31P-NMR in isolated superfused mitochondria embedded in agarose beads showed that Na+ (3–30 mM) led to significantly decreased ATP levels and that this effect was stronger in diabetic rats. These data suggest that in diabetic cardiomyocytes, increased Na+ leads to abnormalities in oxidative phosphorylation and a subsequent decrease in ATP levels. In support of these data, using 31P-NMR, we showed that the baseline β-ATP and phosphocreatine (PCr) were lower in diabetic cardiomyocytes than in control, suggesting that diabetic cardiomyocytes have depressed bioenergetic function. Thus, both altered intracellular Na+ levels and bioenergetics and their interactions may significantly contribute to the pathology of diabetic cardiomyopathy.
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Affiliation(s)
- Nicolai M Doliba
- Department of Biochemistry and Biophysics, Institute for Diabetes, Obesity and Metabolism, School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Andriy M Babsky
- Department of Biophysics and Bioinformatics, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Mary D Osbakken
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, United States
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56
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Arrhythmias precede cardiomyopathy and remodeling of Ca2+ handling proteins in a novel model of long QT syndrome. J Mol Cell Cardiol 2018; 123:13-25. [DOI: 10.1016/j.yjmcc.2018.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/03/2018] [Accepted: 08/21/2018] [Indexed: 01/13/2023]
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57
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Human iPSC-Derived Cardiomyocytes for Investigation of Disease Mechanisms and Therapeutic Strategies in Inherited Arrhythmia Syndromes: Strengths and Limitations. Cardiovasc Drugs Ther 2018; 31:325-344. [PMID: 28721524 PMCID: PMC5550530 DOI: 10.1007/s10557-017-6735-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
During the last two decades, significant progress has been made in the identification of genetic defects underlying inherited arrhythmia syndromes, which has provided some clinical benefit through elucidation of gene-specific arrhythmia triggers and treatment. However, for most arrhythmia syndromes, clinical management is hindered by insufficient knowledge of the functional consequences of the mutation in question, the pro-arrhythmic mechanisms involved, and hence the most optimal treatment strategy. Moreover, disease expressivity and sensitivity to therapeutic interventions often varies between mutations and/or patients, underlining the need for more individualized strategies. The development of the induced pluripotent stem cell (iPSC) technology now provides the opportunity for generating iPSC-derived cardiomyocytes (CMs) from human material (hiPSC-CMs), enabling patient- and/or mutation-specific investigations. These hiPSC-CMs may furthermore be employed for identification and assessment of novel therapeutic strategies for arrhythmia syndromes. However, due to their relative immaturity, hiPSC-CMs also display a number of essential differences as compared to adult human CMs, and hence there are certain limitations in their use. We here review the electrophysiological characteristics of hiPSC-CMs, their use for investigating inherited arrhythmia syndromes, and their applicability for identification and assessment of (novel) anti-arrhythmic treatment strategies.
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58
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Inotropic effect of NCX inhibition depends on the relative activity of the reverse NCX assessed by a novel inhibitor ORM-10962 on canine ventricular myocytes. Eur J Pharmacol 2018; 818:278-286. [DOI: 10.1016/j.ejphar.2017.10.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 01/25/2023]
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59
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Gorski PA, Kho C, Oh JG. Measuring Cardiomyocyte Contractility and Calcium Handling In Vitro. Methods Mol Biol 2018; 1816:93-104. [PMID: 29987813 DOI: 10.1007/978-1-4939-8597-5_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In vitro measurements of cardiomyocyte contractility and Ca2+ handling have been used as a platform for determining physiological consequence of various genetic manipulations and identifying potential therapeutic targets for the treatment of heart failure. The Myocyte Calcium and Contractility System (IonOptix) offers a simultaneous trace of sarcomere movements and changes of intracellular Ca2+ levels in a single cardiomyocyte. Herein, we describe a modified protocol for the isolation of adult cardiomyocytes from murine hearts and provide a step-by-step description on how to analyze cardiomyocyte Ca2+ transient and contractility data collected using the IonOptix system. In our modified protocol, we recommend a novel cannulation technique which simplifies this difficult method and leads to improved viability of isolated cardiomyocytes. In addition, a comprehensive analysis of intracellular Ca2+ handling, SR Ca2+ load, myofilament Ca2+ sensitivity, and cardiomyocyte contractility is described in order to provide important insights into myocardial mechanics.
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Affiliation(s)
- Przemek A Gorski
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Changwon Kho
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jae Gyun Oh
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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60
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Stewart BD, Scott CE, McCoy TP, Yin G, Despa F, Despa S, Kekenes-Huskey PM. Computational modeling of amylin-induced calcium dysregulation in rat ventricular cardiomyocytes. Cell Calcium 2017; 71:65-74. [PMID: 29604965 DOI: 10.1016/j.ceca.2017.11.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 01/08/2023]
Abstract
Hyperamylinemia is a condition that accompanies obesity and precedes type II diabetes, and it is characterized by above-normal blood levels of amylin, the pancreas-derived peptide. Human amylin oligomerizes easily and can deposit in the pancreas [1], brain [2], and heart [3], where they have been associated with calcium dysregulation. In the heart, accumulating evidence suggests that human amylin oligomers form moderately cation-selective [4,5] channels that embed in the cell sarcolemma (SL). The oligomers increase membrane conductance in a concentration-dependent manner [5], which is correlated with elevated cytosolic Ca2+. These findings motivate our core hypothesis that non-selective inward Ca2+ conduction afforded by human amylin oligomers increase cytosolic and sarcoplasmic reticulum (SR) Ca2+ load, which thereby magnifies intracellular Ca2+ transients. Questions remain however regarding the mechanism of amylin-induced Ca2+ dysregulation, including whether enhanced SL Ca2+ influx is sufficient to elevate cytosolic Ca2+ load [6], and if so, how might amplified Ca2+ transients perturb Ca2+-dependent cardiac pathways. To investigate these questions, we modified a computational model of cardiomyocytes Ca2+ signaling to reflect experimentally-measured changes in SL membrane permeation and decreased sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) function stemming from acute and transgenic human amylin peptide exposure. With this model, we confirmed the hypothesis that increasing SL permeation alone was sufficient to enhance Ca2+ transient amplitudes. Our model indicated that amplified cytosolic transients are driven by increased Ca2+ loading of the SR and that greater fractional release may contribute to the Ca2+-dependent activation of calmodulin, which could prime the activation of myocyte remodeling pathways. Importantly, elevated Ca2+ in the SR and dyadic space collectively drive greater fractional SR Ca2+ release for human amylin expressing rats (HIP) and acute amylin-exposed rats (+Amylin) mice, which contributes to the inotropic rise in cytosolic Ca2+ transients. These findings suggest that increased membrane permeation induced by oligomeratization of amylin peptide in cell sarcolemma contributes to Ca2+ dysregulation in pre-diabetes.
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Affiliation(s)
- Bradley D Stewart
- Department of Chemistry, University of Kentucky, 505 Rose St. Chemistry-Physics Building, Lexington, KY 40506, USA
| | - Caitlin E Scott
- Department of Chemistry, University of Kentucky, 505 Rose St. Chemistry-Physics Building, Lexington, KY 40506, USA
| | - Thomas P McCoy
- Department of Family & Community Nursing, University of North Carolina - Greensboro, 1008 Administration Dr. McIver Building, Greensboro, NC 27412, USA
| | - Guo Yin
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, UK Medical Center, MN 150, Lexington, KY 40536, USA
| | - Florin Despa
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, UK Medical Center, MN 150, Lexington, KY 40536, USA
| | - Sanda Despa
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, UK Medical Center, MN 150, Lexington, KY 40536, USA.
| | - Peter M Kekenes-Huskey
- Department of Chemistry, University of Kentucky, 505 Rose St. Chemistry-Physics Building, Lexington, KY 40506, USA.
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61
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Chen J, Wang J, Zhang J, Pu C. Effect of butylphthalide intervention on experimental autoimmune myositis in guinea pigs. Exp Ther Med 2017; 15:152-158. [PMID: 29387187 PMCID: PMC5768128 DOI: 10.3892/etm.2017.5416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 12/19/2016] [Indexed: 02/06/2023] Open
Abstract
Idiopathic inflammatory myopathies are a group of rare muscular diseases that are characterized by acute, subacute or chronic proximal and symmetric muscle weakness, muscle fiber necrosis and infiltration of inflammatory cells, particularly activated CD8+ cytotoxic T cells and phagocytes. 3-n-butylphthalide (NBP) protects mitochondria and reduces the inflammatory response in multiple disease models. In myositis, it has remained elusive whether NBP can protect muscle cells from muscle fiber injury. Experimental autoimmune myositis (EAM) was induced in a total of 40 guinea pigs by myosin immunization. After 4 weeks, low- or high-dose NBP solution was intraperitoneally injected. Saline solution was used as a negative control. After 10 days, the clinical manifestations were assessed by determining rodent grasping power, histopathological changes, Ca2+-adenosinetriphosphatase (ATPase) activity by an ATPase kit, and mRNA expression of interferon (IFN)-γ, retinoic acid receptor-related orphan nuclear receptor (ROR)γt and forkhead box (Fox) p3 in muscle tissue by reverse-transcription quantitative polymerase chain reaction analysis. It was demonstrated that NBP improved the myodynamia of guinea pigs with EAM and reduced the pathological inflammatory cell infiltration in a dose-dependent manner. NBP improved the Ca2+-ATPase activity of the muscle mitochondrial membrane and muscle plasma membrane in animals with EAM. It also reduced the mRNA expression of IFN-γ and RORγt, and significantly increased the mRNA expression of Foxp3 in muscle tissue. These results provided a basis for the consideration of NBP as a novel agent for the treatment of myositis and other muscular diseases associated with autoimmunity and inflammation.
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Affiliation(s)
- Juan Chen
- Department of Neurology, Chinese PLA Medical School, Beijing 100853, P.R. China.,Department of Neurology, The 309th Hospital of PLA, Beijing 100091, P.R. China
| | - Jingyang Wang
- Department of Neurology, Chinese PLA Medical School, Beijing 100853, P.R. China
| | - Jiyan Zhang
- Department of Immunology, Academy of Military Medical Sciences, Beijing 100850, P.R. China
| | - Chuanqiang Pu
- Department of Neurology, Chinese PLA Medical School, Beijing 100853, P.R. China
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62
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Packer M. Activation and Inhibition of Sodium-Hydrogen Exchanger Is a Mechanism That Links the Pathophysiology and Treatment of Diabetes Mellitus With That of Heart Failure. Circulation 2017; 136:1548-1559. [PMID: 29038209 DOI: 10.1161/circulationaha.117.030418] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The mechanisms underlying the progression of diabetes mellitus and heart failure are closely intertwined, such that worsening of one condition is frequently accompanied by worsening of the other; the degree of clinical acceleration is marked when the 2 coexist. Activation of the sodium-hydrogen exchanger in the heart and vasculature (NHE1 isoform) and the kidneys (NHE3 isoform) may serve as a common mechanism that links both disorders and may underlie their interplay. Insulin insensitivity and adipokine abnormalities (the hallmarks of type 2 diabetes mellitus) are characteristic features of heart failure; conversely, neurohormonal systems activated in heart failure (norepinephrine, angiotensin II, aldosterone, and neprilysin) impair insulin sensitivity and contribute to microvascular disease in diabetes mellitus. Each of these neurohormonal derangements may act through increased activity of both NHE1 and NHE3. Drugs used to treat diabetes mellitus may favorably affect the pathophysiological mechanisms of heart failure by inhibiting either or both NHE isoforms, and drugs used to treat heart failure may have beneficial effects on glucose tolerance and the complications of diabetes mellitus by interfering with the actions of NHE1 and NHE3. The efficacy of NHE inhibitors on the risk of cardiovascular events may be enhanced when heart failure and glucose intolerance coexist and may be attenuated when drugs with NHE inhibitory actions are given concomitantly. Therefore, the sodium-hydrogen exchanger may play a central role in the interplay of diabetes mellitus and heart failure, contribute to the physiological and clinical progression of both diseases, and explain certain drug-drug and drug-disease interactions that have been reported in large-scale randomized clinical trials.
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Affiliation(s)
- Milton Packer
- From Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, TX.
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63
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Krogh-Madsen T, Christini DJ. Slow [Na +] i dynamics impacts arrhythmogenesis and spiral wave reentry in cardiac myocyte ionic model. CHAOS (WOODBURY, N.Y.) 2017; 27:093907. [PMID: 28964146 DOI: 10.1063/1.4999475] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Accumulation of intracellular Na+ is gaining recognition as an important regulator of cardiac myocyte electrophysiology. The intracellular Na+ concentration can be an important determinant of the cardiac action potential duration, can modulate the tissue-level conduction of excitation waves, and can alter vulnerability to arrhythmias. Mathematical models of cardiac electrophysiology often incorporate a dynamic intracellular Na+ concentration, which changes much more slowly than the remaining variables. We investigated the dependence of several arrhythmogenesis-related factors on [Na+]i in a mathematical model of the human atrial action potential. In cell simulations, we found that [Na+]i accumulation stabilizes the action potential duration to variations in several conductances and that the slow dynamics of [Na+]i impacts bifurcations to pro-arrhythmic afterdepolarizations, causing intermittency between different rhythms. In long-lasting tissue simulations of spiral wave reentry, [Na+]i becomes spatially heterogeneous with a decreased area around the spiral wave rotation center. This heterogeneous region forms a functional anchor, resulting in diminished meandering of the spiral wave. Our findings suggest that slow, physiological, rate-dependent variations in [Na+]i may play complex roles in cellular and tissue-level cardiac dynamics.
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Affiliation(s)
- Trine Krogh-Madsen
- Greenberg Division of Cardiology, Weill Cornell Medicine, New York, New York 10065, USA; Institute for Computational Biomedicine, Weill Cornell Medicine, New York, New York 10065, USA; and Cardiovascular Research Institute, Weill Cornell Medicine, New York, New York 10065, USA
| | - David J Christini
- Greenberg Division of Cardiology, Weill Cornell Medicine, New York, New York 10065, USA; Institute for Computational Biomedicine, Weill Cornell Medicine, New York, New York 10065, USA; and Cardiovascular Research Institute, Weill Cornell Medicine, New York, New York 10065, USA
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64
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65
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Hegyi B, Bányász T, Shannon TR, Chen-Izu Y, Izu LT. Electrophysiological Determination of Submembrane Na(+) Concentration in Cardiac Myocytes. Biophys J 2017; 111:1304-1315. [PMID: 27653489 DOI: 10.1016/j.bpj.2016.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 08/05/2016] [Accepted: 08/08/2016] [Indexed: 12/19/2022] Open
Abstract
In the heart, Na(+) is a key modulator of the action potential, Ca(2+) homeostasis, energetics, and contractility. Because Na(+) currents and cotransport fluxes depend on the Na(+) concentration in the submembrane region, it is necessary to accurately estimate the submembrane Na(+) concentration ([Na(+)]sm). Current methods using Na(+)-sensitive fluorescent indicators or Na(+) -sensitive electrodes cannot measure [Na(+)]sm. However, electrophysiology methods are ideal for measuring [Na(+)]sm. In this article, we develop patch-clamp protocols and experimental conditions to determine the upper bound of [Na(+)]sm at the peak of action potential and its lower bound at the resting state. During the cardiac cycle, the value of [Na(+)]sm is constrained within these bounds. We conducted experiments in rabbit ventricular myocytes at body temperature and found that 1) at a low pacing frequency of 0.5 Hz, the upper and lower bounds converge at 9 mM, constraining the [Na(+)]sm value to ∼9 mM; 2) at 2 Hz pacing frequency, [Na(+)]sm is bounded between 9 mM at resting state and 11.5 mM; and 3) the cells can maintain [Na(+)]sm to the above values, despite changes in the pipette Na(+) concentration, showing autoregulation of Na(+) in beating cardiomyocytes.
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Affiliation(s)
- Bence Hegyi
- Department of Pharmacology, University of California, Davis, Davis, California
| | - Tamás Bányász
- Department of Pharmacology, University of California, Davis, Davis, California; Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Thomas R Shannon
- Department of Molecular Physiology and Biophysics, Rush University School of Medicine, Chicago, Illinois
| | - Ye Chen-Izu
- Department of Pharmacology, University of California, Davis, Davis, California; Department of Biomedical Engineering, University of California, Davis, Davis, California; Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, California
| | - Leighton T Izu
- Department of Pharmacology, University of California, Davis, Davis, California.
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66
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Abstract
Sachse et al. highlight work that reveals a Na+-dependent inactivation mechanism in the Na+/K+ pump.
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Affiliation(s)
- Frank B Sachse
- Department of Bioengineering and Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT
| | - Robert Clark
- Faculties of Kinesiology and Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Wayne R Giles
- Faculties of Kinesiology and Medicine, University of Calgary, Calgary, Alberta, Canada
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67
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Britton OJ, Bueno-Orovio A, Virág L, Varró A, Rodriguez B. The Electrogenic Na +/K + Pump Is a Key Determinant of Repolarization Abnormality Susceptibility in Human Ventricular Cardiomyocytes: A Population-Based Simulation Study. Front Physiol 2017; 8:278. [PMID: 28529489 PMCID: PMC5418229 DOI: 10.3389/fphys.2017.00278] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/18/2017] [Indexed: 11/23/2022] Open
Abstract
Background: Cellular repolarization abnormalities occur unpredictably due to disease and drug effects, and can occur even in cardiomyocytes that exhibit normal action potentials (AP) under control conditions. Variability in ion channel densities may explain differences in this susceptibility to repolarization abnormalities. Here, we quantify the importance of key ionic mechanisms determining repolarization abnormalities following ionic block in human cardiomyocytes yielding normal APs under control conditions. Methods and Results: Sixty two AP recordings from non-diseased human heart preparations were used to construct a population of human ventricular models with normal APs and a wide range of ion channel densities. Multichannel ionic block was applied to investigate susceptibility to repolarization abnormalities. IKr block was necessary for the development of repolarization abnormalities. Models that developed repolarization abnormalities over the widest range of blocks possessed low Na+/K+ pump conductance below 50% of baseline, and ICaL conductance above 70% of baseline. Furthermore, INaK made the second largest contribution to repolarizing current in control simulations and the largest contribution under 75% IKr block. Reversing intracellular Na+ overload caused by reduced INaK was not sufficient to prevent abnormalities in models with low Na+/K+ pump conductance, while returning Na+/K+ pump conductance to normal substantially reduced abnormality occurrence, indicating INaK is an important repolarization current. Conclusions: INaK is an important determinant of repolarization abnormality susceptibility in human ventricular cardiomyocytes, through its contribution to repolarization current rather than homeostasis. While we found IKr block to be necessary for repolarization abnormalities to occur, INaK decrease, as in disease, may amplify the pro-arrhythmic risk of drug-induced IKr block in humans.
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Affiliation(s)
| | | | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of SzegedSzeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of SzegedSzeged, Hungary
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Rozier K, Bondarenko VE. Distinct physiological effects of β1- and β2-adrenoceptors in mouse ventricular myocytes: insights from a compartmentalized mathematical model. Am J Physiol Cell Physiol 2017; 312:C595-C623. [DOI: 10.1152/ajpcell.00273.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 01/03/2017] [Accepted: 01/18/2017] [Indexed: 01/08/2023]
Abstract
The β1- and β2-adrenergic signaling systems play different roles in the functioning of cardiac cells. Experimental data show that the activation of the β1-adrenergic signaling system produces significant inotropic, lusitropic, and chronotropic effects in the heart, whereas the effects of the β2-adrenergic signaling system is less apparent. In this paper, a comprehensive compartmentalized experimentally based mathematical model of the combined β1- and β2-adrenergic signaling systems in mouse ventricular myocytes is developed to simulate the experimental findings and make testable predictions of the behavior of the cardiac cells under different physiological conditions. Simulations describe the dynamics of major signaling molecules in different subcellular compartments; kinetics and magnitudes of phosphorylation of ion channels, transporters, and Ca2+ handling proteins; modifications of action potential shape and duration; and [Ca2+]i and [Na+]i dynamics upon stimulation of β1- and β2-adrenergic receptors (β1- and β2-ARs). The model reveals physiological conditions when β2-ARs do not produce significant physiological effects and when their effects can be measured experimentally. Simulations demonstrated that stimulation of β2-ARs with isoproterenol caused a marked increase in the magnitude of the L-type Ca2+ current, [Ca2+]i transient, and phosphorylation of phospholamban only upon additional application of pertussis toxin or inhibition of phosphodiesterases of type 3 and 4. The model also made testable predictions of the changes in magnitudes of [Ca2+]i and [Na+]i fluxes, the rate of decay of [Na+]i concentration upon both combined and separate stimulation of β1- and β2-ARs, and the contribution of phosphorylation of PKA targets to the changes in the action potential and [Ca2+]i transient.
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Affiliation(s)
- Kelvin Rozier
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia; and
| | - Vladimir E. Bondarenko
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia; and
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
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69
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Yang Z, Prinsen JK, Bersell KR, Shen W, Yermalitskaya L, Sidorova T, Luis PB, Hall L, Zhang W, Du L, Milne G, Tucker P, George AL, Campbell CM, Pickett RA, Shaffer CM, Chopra N, Yang T, Knollmann BC, Roden DM, Murray KT. Azithromycin Causes a Novel Proarrhythmic Syndrome. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.115.003560. [PMID: 28408648 DOI: 10.1161/circep.115.003560] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/26/2017] [Indexed: 01/20/2023]
Abstract
BACKGROUND The widely used macrolide antibiotic azithromycin increases risk of cardiovascular and sudden cardiac death, although the underlying mechanisms are unclear. Case reports, including the one we document here, demonstrate that azithromycin can cause rapid, polymorphic ventricular tachycardia in the absence of QT prolongation, indicating a novel proarrhythmic syndrome. We investigated the electrophysiological effects of azithromycin in vivo and in vitro using mice, cardiomyocytes, and human ion channels heterologously expressed in human embryonic kidney (HEK 293) and Chinese hamster ovary (CHO) cells. METHODS AND RESULTS In conscious telemetered mice, acute intraperitoneal and oral administration of azithromycin caused effects consistent with multi-ion channel block, with significant sinus slowing and increased PR, QRS, QT, and QTc intervals, as seen with azithromycin overdose. Similarly, in HL-1 cardiomyocytes, the drug slowed sinus automaticity, reduced phase 0 upstroke slope, and prolonged action potential duration. Acute exposure to azithromycin reduced peak SCN5A currents in HEK cells (IC50=110±3 μmol/L) and Na+ current in mouse ventricular myocytes. However, with chronic (24 hour) exposure, azithromycin caused a ≈2-fold increase in both peak and late SCN5A currents, with findings confirmed for INa in cardiomyocytes. Mild block occurred for K+ currents representing IKr (CHO cells expressing hERG; IC50=219±21 μmol/L) and IKs (CHO cells expressing KCNQ1+KCNE1; IC50=184±12 μmol/L), whereas azithromycin suppressed L-type Ca++ currents (rabbit ventricular myocytes, IC50=66.5±4 μmol/L) and IK1 (HEK cells expressing Kir2.1, IC50=44±3 μmol/L). CONCLUSIONS Chronic exposure to azithromycin increases cardiac Na+ current to promote intracellular Na+ loading, providing a potential mechanistic basis for the novel form of proarrhythmia seen with this macrolide antibiotic.
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Affiliation(s)
- Zhenjiang Yang
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Joseph K Prinsen
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Kevin R Bersell
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Wangzhen Shen
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Liudmila Yermalitskaya
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Tatiana Sidorova
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Paula B Luis
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Lynn Hall
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Wei Zhang
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Liping Du
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Ginger Milne
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Patrick Tucker
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Alfred L George
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Courtney M Campbell
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Robert A Pickett
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Christian M Shaffer
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Nagesh Chopra
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Tao Yang
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Bjorn C Knollmann
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Dan M Roden
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN
| | - Katherine T Murray
- From the Department of Medicine and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN.
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70
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Yan X, Xun M, Dou X, Wu L, Zhang F, Zheng J. Activation of Na+-K+-ATPase with DRm217 attenuates oxidative stress-induced myocardial cell injury via closing Na+-K+-ATPase/Src/Ros amplifier. Apoptosis 2017; 22:531-543. [DOI: 10.1007/s10495-016-1342-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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71
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Zhang Y, Wang HM, Wang YZ, Zhang YY, Jin XX, Zhao Y, Wang J, Sun YL, Xue GL, Li PH, Huang QH, Yang BF, Pan ZW. Increment of late sodium currents in the left atrial myocytes and its potential contribution to increased susceptibility of atrial fibrillation in castrated male mice. Heart Rhythm 2017; 14:1073-1080. [PMID: 28185917 DOI: 10.1016/j.hrthm.2017.01.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND The incidence of atrial fibrillation (AF) is correlated with decreased levels of testosterone in elderly men. Late sodium current may exert a role in AF pathogenesis. OBJECTIVE The purpose of this study was to explore the effect of testosterone deficiency on AF susceptibility and the therapeutic effect of late sodium current inhibitors in mice. METHODS Male ICR mice (5 weeks old) were castrated to establish a testosterone deficiency model. One month after castration, dihydrotestosterone 5 mg/kg was administered subcutaneously for 2 months. Serum total testosterone level was assessed by enzyme-linked immunosorbent assay. High-frequency electrical stimulation was used to induce atrial arrhythmias. Whole-cell patch-clamp technique was used to for single-cell electrophysiologic study. RESULTS Serum dihydrotestosterone levels of castration mice declined significantly but recovered with administration of exogenous dihydrotestosterone. In comparison with sham mice, the number of AF episodes significantly increased by 13.5-fold, AF rate increased by 3.75-fold, and AF duration prolonged in castrated mice. Dihydrotestosterone administration alleviated the occurrence of AF. Action potential duration at both 50% and 90% repolarization were markedly increased in castrated mice compared to sham controls. The late sodium current was enhanced in castrated male mice. These alterations were alleviated by treatment with dihydrotestosterone. Systemic application of the INa-L inhibitors ranolazine, eleclazine, and GS967 inhibited the occurrence of AF in castrated mice. CONCLUSION Testosterone deficiency contributed to the increased late sodium current, prolonged action potential repolarization, and increased susceptibility to AF. Blocking of late sodium current is beneficial against the occurrence of AF in castrated mice.
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Affiliation(s)
- Yang Zhang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Hui-Min Wang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Ying-Zhe Wang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Yi-Yuan Zhang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Xue-Xin Jin
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Yue Zhao
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Jin Wang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Yi-Lin Sun
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Gen-Long Xue
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Peng-Hui Li
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Qi-He Huang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Bao-Feng Yang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China; Department of Pharmacology and Therapeutics, Melbourne School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia
| | - Zhen-Wei Pan
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China.
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Hosseinzadeh Z, Singh Y, Shimshek DR, van der Putten H, Wagner CA, Lang F. Leucine-Rich Repeat Kinase 2 (Lrrk2)-Sensitive Na +/K + ATPase Activity in Dendritic Cells. Sci Rep 2017; 7:41117. [PMID: 28120865 PMCID: PMC5264149 DOI: 10.1038/srep41117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/14/2016] [Indexed: 12/18/2022] Open
Abstract
Leucine-rich repeat kinase 2 (Lrrk2) has been implicated in the pathophysiology of Parkinson's disease. Lrrk2 is expressed in diverse cells including neurons and dendritic cells (DCs). In DCs Lrrk2 was shown to up-regulate Na+/Ca2+-exchanger activity. The elimination of Ca2+ by Na+/Ca2+ -exchangers requires maintenance of the Na+ gradient by the Na+/K+ -ATPase. The present study thus explored whether Lrrk2 impacts on Na+/K+ -ATPase expression and function. To this end DCs were isolated from gene-targeted mice lacking Lrrk2 (Lrrk2-/-) and their wild-type littermates (Lrrk2+/+). Na+/K+ -ATPase activity was estimated from K+ induced, ouabain sensitive, current determined by whole cell patch clamp. Na+/K+ -ATPase α1 subunit transcript and protein levels were determined by RT-qPCR and flow cytometry. As a result, the K+ induced current was significantly smaller in Lrrk2-/- than in Lrrk2+/+ DCs and was completely abolished by ouabain (100 μM) in both genotypes. The K+ induced, ouabain sensitive, current in Lrrk2+/+ DCs was significantly blunted by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). The Na+/K+ -ATPase α1 subunit transcript and protein levels were significantly lower in Lrrk2-/- than in Lrrk2+/+ DCs and significantly decreased by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). In conclusion, Lrrk2 is a powerful regulator of Na+/K+ -ATPase expression and activity in dendritic cells.
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Affiliation(s)
- Zohreh Hosseinzadeh
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
- Experimental Retinal Prosthetics Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Yogesh Singh
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
| | - Derya R. Shimshek
- Department of Neuroscience, Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland
| | - Herman van der Putten
- Department of Neuroscience, Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland
- National Contest for Life (NCL) Foundation, 203555 Hamburg, Germany
| | - Carsten A. Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Florian Lang
- Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
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Cardona K, Trenor B, Giles WR. Changes in Intracellular Na+ following Enhancement of Late Na+ Current in Virtual Human Ventricular Myocytes. PLoS One 2016; 11:e0167060. [PMID: 27875582 PMCID: PMC5119830 DOI: 10.1371/journal.pone.0167060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 11/08/2016] [Indexed: 12/19/2022] Open
Abstract
The slowly inactivating or late Na+ current, INa-L, can contribute to the initiation of both atrial and ventricular rhythm disturbances in the human heart. However, the cellular and molecular mechanisms that underlie these pro-arrhythmic influences are not fully understood. At present, the major working hypothesis is that the Na+ influx corresponding to INa-L significantly increases intracellular Na+, [Na+]i; and the resulting reduction in the electrochemical driving force for Na+ reduces and (may reverse) Na+/Ca2+ exchange. These changes increase intracellular Ca2+, [Ca2+]i; which may further enhance INa-L due to calmodulin-dependent phosphorylation of the Na+ channels. This paper is based on mathematical simulations using the O'Hara et al (2011) model of baseline or healthy human ventricular action potential waveforms(s) and its [Ca2+]i homeostasis mechanisms. Somewhat surprisingly, our results reveal only very small changes (≤ 1.5 mM) in [Na+]i even when INa-L is increased 5-fold and steady-state stimulation rate is approximately 2 times the normal human heart rate (i.e. 2 Hz). Previous work done using well-established models of the rabbit and human ventricular action potential in heart failure settings also reported little or no change in [Na+]i when INa-L was increased. Based on our simulations, the major short-term effect of markedly augmenting INa-L is a significant prolongation of the action potential and an associated increase in the likelihood of reactivation of the L-type Ca2+ current, ICa-L. Furthermore, this action potential prolongation does not contribute to [Na+]i increase.
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Affiliation(s)
- Karen Cardona
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Beatriz Trenor
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
- * E-mail:
| | - Wayne R. Giles
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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Kawada T, Akiyama T, Li M, Zheng C, Turner MJ, Shirai M, Sugimachi M. Acute arterial baroreflex-mediated changes in plasma catecholamine concentrations in a chronic rat model of myocardial infarction. Physiol Rep 2016; 4:4/15/e12880. [PMID: 27495297 PMCID: PMC4985546 DOI: 10.14814/phy2.12880] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 06/23/2016] [Indexed: 11/24/2022] Open
Abstract
While it may be predictable that plasma norepinephrine (NE) concentration changes with efferent sympathetic nerve activity (SNA) in response to baroreceptor pressure inputs, an exact relationship between SNA and plasma NE concentration remains to be quantified in heart failure. We examined acute baroreflex-mediated changes in plasma NE and epinephrine (Epi) concentrations in normal control (NC) rats and rats with myocardial infarction (MI) (n = 6 each). Plasma NE concentration correlated linearly with SNA in the NC group (slope: 2.17 ± 0.26 pg mL(-1) %(-1), intercept: 20.0 ± 18.2 pg mL(-1)) and also in the MI group (slope: 19.20 ± 6.45 pg mL(-1) %(-1), intercept: -239.6 ± 200.0 pg mL(-1)). The slope was approximately nine times higher in the MI than in the NC group (P < 0.01). Plasma Epi concentration positively correlated with SNA in the NC group (slope: 1.65 ± 0.79 pg mL(-1) %(-1), intercept: 115.0 ± 69.5 pg mL(-1)) and also in the MI group (slope: 7.74 ± 2.20 pg mL(-1) %(-1), intercept: 24.7 ± 120.1 pg mL(-1)). The slope was approximately 4.5 times higher in the MI than in the NC group (P < 0.05). Intravenous administration of desipramine (1 mg kg(-1)) significantly increased plasma NE concentration but decreased plasma Epi concentration in both groups, suggesting that neuronal NE uptake had contributed to the reduction in plasma NE concentration. These results indicate that high levels of plasma catecholamine in MI rats were still under the influence of baroreflex-mediated changes in SNA, and may provide additional rationale for applying baroreflex activation therapy in patients with chronic heart failure.
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Affiliation(s)
- Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Tsuyoshi Akiyama
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Meihua Li
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Can Zheng
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Michael J Turner
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Mikiyasu Shirai
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
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75
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Yu X, Hong F, Zhang YQ. Cardiac inflammation involving in PKCε or ERK1/2-activated NF-κB signalling pathway in mice following exposure to titanium dioxide nanoparticles. JOURNAL OF HAZARDOUS MATERIALS 2016; 313:68-77. [PMID: 27054666 DOI: 10.1016/j.jhazmat.2016.03.088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/15/2016] [Accepted: 03/30/2016] [Indexed: 06/05/2023]
Abstract
The evaluation of toxicological effects of nanoparticles (NPs) is increasingly important due to their growing occupational use and presence as compounds in consumer products. Recent researches have demonstrated that long-term exposure to air particulate matter can induce cardiovascular events, but whether cardiovascular disease, such as cardiac damage, is induced by NP exposure and its toxic mechanisms is rarely evaluated. In the present study, when mice were continuously exposed to TiO2 NPs at 2.5, 5 or 10mg/kg BW by intragastric administration for 90days, obvious histopathological changes, and great alterations of NF-κB and its inhibitor I-κB, as well as TNF-α, IL-1β, IL-6 and IFN-α expression were induced. The NPs significantly decreased Ca(2+)-ATPase, Ca(2+)/Mg(2+)-ATPase and Na(+)/K(+)-ATPase activities and enhanced NCX-1 content. The NPs also considerably increased CAMK II and α1/β1-AR expression and up-regulated p-PKCε and p-ERK1/2 in a dose-dependent manner in the mouse heart. These data suggest that low-dose and long-term exposure to TiO2 NPs may cause cardiac damage such as cardiac fragmentation or disordered myocardial fibre arrangement, tissue necrosis, myocardial haemorrhage, swelling or cardiomyocyte hypertrophy, and the inflammatory response was potentially mediated by NF-κB activation via the PKCε or ERK1/2 signalling cascades in mice.
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Affiliation(s)
- Xiaohong Yu
- Department of Applied Biology, School of Basic Medical and Biological Sciences, Soochow University, RM 702-2303, Renai Road No. 199, Dushuhu Higher Edu. Town, Suzhou 215123, China
| | - Fashui Hong
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture and Environmental Protection, Huaiyin Normal University, Huaian 223300, China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, Huaiyin Normal University, Huaian 223300, China.
| | - Yu-Qing Zhang
- Department of Applied Biology, School of Basic Medical and Biological Sciences, Soochow University, RM 702-2303, Renai Road No. 199, Dushuhu Higher Edu. Town, Suzhou 215123, China.
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Blaustein MP, Chen L, Hamlyn JM, Leenen FHH, Lingrel JB, Wier WG, Zhang J. Pivotal role of α2 Na + pumps and their high affinity ouabain binding site in cardiovascular health and disease. J Physiol 2016; 594:6079-6103. [PMID: 27350568 DOI: 10.1113/jp272419] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/18/2016] [Indexed: 12/13/2022] Open
Abstract
Reduced smooth muscle (SM)-specific α2 Na+ pump expression elevates basal blood pressure (BP) and increases BP sensitivity to angiotensin II (Ang II) and dietary NaCl, whilst SM-α2 overexpression lowers basal BP and decreases Ang II/salt sensitivity. Prolonged ouabain infusion induces hypertension in rodents, and ouabain-resistant mutation of the α2 ouabain binding site (α2R/R mice) confers resistance to several forms of hypertension. Pressure overload-induced heart hypertrophy and failure are attenuated in cardio-specific α2 knockout, cardio-specific α2 overexpression and α2R/R mice. We propose a unifying hypothesis that reconciles these apparently disparate findings: brain mechanisms, activated by Ang II and high NaCl, regulate sympathetic drive and a novel neurohumoral pathway mediated by both brain and circulating endogenous ouabain (EO). Circulating EO modulates ouabain-sensitive α2 Na+ pump activity and Ca2+ transporter expression and, via Na+ /Ca2+ exchange, Ca2+ homeostasis. This regulates sensitivity to sympathetic activity, Ca2+ signalling and arterial and cardiac contraction.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Ling Chen
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Frans H H Leenen
- Hypertension Unit, University of Ottawa Heart Institute, Ottawa, ON, Canada, K1Y 4W7
| | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524, USA
| | - W Gil Wier
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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77
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Abstract
The aim of this review is to provide the reader with a synopsis of some of the emerging ideas and experimental findings in cardiac physiology and pathophysiology that were published in 2015. To provide context for the non-specialist, a brief summary of cardiac contraction and calcium (Ca) regulation in the heart in health and disease is provided. Thereafter, some recently published articles are introduced that indicate the current thinking on (1) the Ca regulatory pathways modulated by Ca/calmodulin-dependent protein kinase II, (2) the potential influences of nitrosylation by nitric oxide or S-nitrosated proteins, (3) newly observed effects of reactive oxygen species (ROS) on contraction and Ca regulation following myocardial infarction and a possible link with changes in mitochondrial Ca, and (4) the effects of some of these signaling pathways on late Na current and pro-arrhythmic afterdepolarizations as well as the effects of transverse tubule disturbances.
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Affiliation(s)
- Ken T MacLeod
- Faculty of Medicine, National Heart & Lung Institute, Imperial College London, London, UK
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78
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Acsai K, Ördög B, Varró A, Nánási PP. Role of the dysfunctional ryanodine receptor - Na(+)-Ca(2+)exchanger axis in progression of cardiovascular diseases: What we can learn from pharmacological studies? Eur J Pharmacol 2016; 779:91-101. [PMID: 26970182 DOI: 10.1016/j.ejphar.2016.03.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 03/04/2016] [Accepted: 03/07/2016] [Indexed: 12/28/2022]
Abstract
Abnormal Ca(2+)homeostasis is often associated with chronic cardiovascular diseases, such as hypertension, heart failure or cardiac arrhythmias, and typically contributes to the basic ethiology of the disease. Pharmacological targeting of cardiac Ca(2+)handling has great therapeutic potential offering invaluable options for the prevention, slowing down the progression or suppression of the harmful outcomes like life threatening cardiac arrhythmias. In this review we outline the existing knowledge on the involvement of malfunction of the ryanodine receptor and the Na(+)-Ca(2+)exchanger in disturbances of Ca(2+)homeostasis and discuss important proof of concept pharmacological studies targeting these mechanisms in context of hypertension, heart failure, atrial fibrillation and ventricular arrhythmias. We emphasize the promising results of preclinical studies underpinning the potential benefits of the therapeutic strategies based on ryanodine receptor or Na(+)-Ca(2+)exchanger inhibition.
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Affiliation(s)
- Károly Acsai
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - Balázs Ördög
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Faculty of Medicine, Szeged, Hungary
| | - András Varró
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary; Department of Pharmacology and Pharmacotherapy, University of Szeged, Faculty of Medicine, Szeged, Hungary
| | - Péter P Nánási
- Department of Physiology, University of Debrecen, Debrecen, Hungary; Department of Dentistry, University of Debrecen, Debrecen, Hungary.
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79
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Primessnig U, Schönleitner P, Höll A, Pfeiffer S, Bracic T, Rau T, Kapl M, Stojakovic T, Glasnov T, Leineweber K, Wakula P, Antoons G, Pieske B, Heinzel FR. Novel pathomechanisms of cardiomyocyte dysfunction in a model of heart failure with preserved ejection fraction. Eur J Heart Fail 2016; 18:987-97. [DOI: 10.1002/ejhf.524] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 02/16/2016] [Indexed: 12/24/2022] Open
Affiliation(s)
- Uwe Primessnig
- Department of Cardiology; Charité University Medicine Berlin; Campus Virchow-Klinikum Berlin Germany
- Department of Cardiology; Medical University of Graz; Graz Austria
- German Centre for Cardiovascular Research (DZHK); partner site Berlin, Germany
| | - Patrick Schönleitner
- Department of Cardiology; Medical University of Graz; Graz Austria
- Department of Physiology; Maastricht University; Maastricht The Netherlands
| | - Alexander Höll
- Department of Cardiology; Medical University of Graz; Graz Austria
| | - Susanne Pfeiffer
- Department of Cardiology; Medical University of Graz; Graz Austria
| | - Taja Bracic
- Department of Cardiology; Medical University of Graz; Graz Austria
| | - Thomas Rau
- Department of Cardiology; Medical University of Graz; Graz Austria
| | - Martin Kapl
- Department of Cardiology; Medical University of Graz; Graz Austria
| | - Tatjana Stojakovic
- Clinical Institute of Medical and Chemical Laboratory Diagnostics; Medical University of Graz; Graz Austria
| | - Toma Glasnov
- Institute of Chemistry; University of Graz; Graz Austria
| | | | - Paulina Wakula
- Department of Cardiology; Charité University Medicine Berlin; Campus Virchow-Klinikum Berlin Germany
- German Centre for Cardiovascular Research (DZHK); partner site Berlin, Germany
| | - Gudrun Antoons
- Department of Cardiology; Medical University of Graz; Graz Austria
- Department of Physiology; Maastricht University; Maastricht The Netherlands
| | - Burkert Pieske
- Department of Cardiology; Charité University Medicine Berlin; Campus Virchow-Klinikum Berlin Germany
- Department of Cardiology; Medical University of Graz; Graz Austria
- German Centre for Cardiovascular Research (DZHK); partner site Berlin, Germany
| | - Frank R. Heinzel
- Department of Cardiology; Charité University Medicine Berlin; Campus Virchow-Klinikum Berlin Germany
- Department of Cardiology; Medical University of Graz; Graz Austria
- German Centre for Cardiovascular Research (DZHK); partner site Berlin, Germany
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80
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Liu M, Yang KC, Dudley SC. Cardiac Sodium Channel Mutations: Why so Many Phenotypes? CURRENT TOPICS IN MEMBRANES 2016; 78:513-59. [PMID: 27586294 DOI: 10.1016/bs.ctm.2015.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cardiac Na(+) channel (Nav1.5) conducts a depolarizing inward Na(+) current that is responsible for the generation of the upstroke Phase 0 of the action potential. In heart tissue, changes in Na(+) currents can affect conduction velocity and impulse propagation. The cardiac Nav1.5 is also involved in determination of the action potential duration, since some channels may reopen during the plateau phase, generating a persistent or late inward current. Mutations of cardiac Nav1.5 can induce gain or loss of channel function because of an increased late current or a decrease of peak current, respectively. Gain-of-function mutations cause Long QT syndrome type 3 and possibly atrial fibrillation, while loss-of-function channel mutations are associated with a wider variety of phenotypes, such as Brugada syndrome, cardiac conduction disease, dilated cardiomyopathy, and sick sinus node syndrome. The penetrance and phenotypes resulting from Nav1.5 mutations also vary with age, gender, body temperature, circadian rhythm, and between regions of the heart. This phenotypic variability makes it difficult to correlate genotype-phenotype. We propose that mutations are only one contributor to the phenotype and additional modifications on Nav1.5 lead to the phenotypic variability. Possible modifiers include other genetic variations and alterations in the life cycle of Nav1.5 such as gene transcription, RNA processing, translation, posttranslational modifications, trafficking, complex assembly, and degradation. In this chapter, we summarize potential modifiers of cardiac Nav1.5 that could help explain the clinically observed phenotypic variability. Consideration of these modifiers could help improve genotype-phenotype correlations and lead to new therapeutic strategies.
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Affiliation(s)
- M Liu
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - K-C Yang
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - S C Dudley
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
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81
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The basal function of teleost prolactin as a key regulator on ion uptake identified with zebrafish knockout models. Sci Rep 2016; 6:18597. [PMID: 26726070 PMCID: PMC4698586 DOI: 10.1038/srep18597] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 11/03/2015] [Indexed: 12/20/2022] Open
Abstract
Prolactin (PRL) is an anterior pituitary hormone with a broad range of functions. Its ability to stimulate lactogenesis, maternal behavior, growth and development, osmoregulation, and epithelial ion transport has been reported in many vertebrates. In our present study, we have targeted the zebrafish prl locus via transcription activator-like effector nucleases (TALENs). Two independent targeted mutant lines with premature termination of the putative sequence of PRL peptides were generated. All prl-deficient zebrafish progeny died at 6–16 days post-fertilization stage (dpf) in egg water. However, the prl-deficient larvae thrived and survived through adulthood in brackish water (5175 mg/L ocean salts), without obvious defects in somatic growth or reproduction. When raised in egg water, the expression levels of certain key Na+/Cl− cotransporters in the gills and Na+/K+-ATPase subunits, Na+/H+ exchangers and Na+/Cl− transporters in the pronephros of prl-deficient larvae were down-regulated at 5 dpf, which caused Na+/K+/Cl− uptake defects in the mutant fish at 6 dpf. Our present results demonstrate that the primary function of zebrafish prl is osmoregulation via governing the uptake and homeostasis of Na+, K+ and Cl−. Our study provides valuable evidence to understand the mechanisms of PRL function better through both phylogenetic and physiological perspectives.
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82
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Ortega A, Tarazón E, Roselló-Lletí E, Gil-Cayuela C, Lago F, González-Juanatey JR, Cinca J, Jorge E, Martínez-Dolz L, Portolés M, Rivera M. Patients with Dilated Cardiomyopathy and Sustained Monomorphic Ventricular Tachycardia Show Up-Regulation of KCNN3 and KCNJ2 Genes and CACNG8-Linked Left Ventricular Dysfunction. PLoS One 2015; 10:e0145518. [PMID: 26710323 PMCID: PMC4692400 DOI: 10.1371/journal.pone.0145518] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/05/2015] [Indexed: 01/26/2023] Open
Abstract
AIMS Disruptions in cardiac ion channels have shown to influence the impaired cardiac contraction in heart failure. We sought to determine the altered gene expression profile of this category in dilated cardiomyopathy (DCM) patients and relate the altered gene expression with the clinical signs present in our patients, such as ventricular dysfunction and sustained monomorphic ventricular tachycardia (SMVT). METHODS AND RESULTS Left ventricular (LV) tissue samples were used in RNA-sequencing technique to elucidate the transcriptomic changes of 13 DCM patients compared to controls (n = 10). We analyzed the differential gene expression of cardiac ion channels, and we found a total of 34 altered genes. We found that the calcium channel CACNG8 mRNA and protein levels were down-regulated and highly and inversely related with LV ejection fraction (LVEF) (r = -0.78, P<0.01). Furthermore, the potassium channels KCNN3 and KCNJ2 mRNA and protein levels were up-regulated and showed also a significant and inverse correlation with LVEF (r = -0.61, P<0.05; r = -0.60, P<0.05) in patients with SMVT. CONCLUSION A broad set of deregulated genes have been identified by RNA-sequencing technique. The relationship of CACNG8, KCNN3 and KCNJ2 with LVEF, and the up-regulation of KCNN3 and KCNJ2 in all patients with SMVT, irrespective of CACNG8 expression, suggest a significant role for these three ion flux related genes in the LV dysfunction present in this cardiomyopathy and an important relationship between KCNN3 and KCNJ2 up-regulation and the presence of SMVT.
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Affiliation(s)
- Ana Ortega
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Estefanía Tarazón
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Esther Roselló-Lletí
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Carolina Gil-Cayuela
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Francisca Lago
- Cellular and Molecular Cardiology Research Unit, Department of Cardiology and Institute of Biomedical Research, University Clinical Hospital, Santiago de Compostela, Spain
| | - Jose-Ramón González-Juanatey
- Cellular and Molecular Cardiology Research Unit, Department of Cardiology and Institute of Biomedical Research, University Clinical Hospital, Santiago de Compostela, Spain
| | - Juan Cinca
- Cardiology Service of Santa Creu i Sant Pau Hospital, Barcelona, Spain
| | - Esther Jorge
- Cardiology Service of Santa Creu i Sant Pau Hospital, Barcelona, Spain
| | - Luis Martínez-Dolz
- Heart Failure and Transplantation Unit, Cardiology Department, La Fe University Hospital, Valencia, Spain
| | - Manuel Portolés
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Miguel Rivera
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
- * E-mail:
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83
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Clancy CE, Chen-Izu Y, Bers DM, Belardinelli L, Boyden PA, Csernoch L, Despa S, Fermini B, Hool LC, Izu L, Kass RS, Lederer WJ, Louch WE, Maack C, Matiazzi A, Qu Z, Rajamani S, Rippinger CM, Sejersted OM, O'Rourke B, Weiss JN, Varró A, Zaza A. Deranged sodium to sudden death. J Physiol 2015; 593:1331-45. [PMID: 25772289 DOI: 10.1113/jphysiol.2014.281204] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/14/2014] [Indexed: 12/19/2022] Open
Abstract
In February 2014, a group of scientists convened as part of the University of California Davis Cardiovascular Symposium to bring together experimental and mathematical modelling perspectives and discuss points of consensus and controversy on the topic of sodium in the heart. This paper summarizes the topics of presentation and discussion from the symposium, with a focus on the role of aberrant sodium channels and abnormal sodium homeostasis in cardiac arrhythmias and pharmacotherapy from the subcellular scale to the whole heart. Two following papers focus on Na(+) channel structure, function and regulation, and Na(+)/Ca(2+) exchange and Na(+)/K(+) ATPase. The UC Davis Cardiovascular Symposium is a biannual event that aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The focus on Na(+) in the 2014 symposium stemmed from the multitude of recent studies that point to the importance of maintaining Na(+) homeostasis in the heart, as disruption of homeostatic processes are increasingly identified in cardiac disease states. Understanding how disruption in cardiac Na(+)-based processes leads to derangement in multiple cardiac components at the level of the cell and to then connect these perturbations to emergent behaviour in the heart to cause disease is a critical area of research. The ubiquity of disruption of Na(+) channels and Na(+) homeostasis in cardiac disorders of excitability and mechanics emphasizes the importance of a fundamental understanding of the associated mechanisms and disease processes to ultimately reveal new targets for human therapy.
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Affiliation(s)
- Colleen E Clancy
- Department of Pharmacology, University of California, Davis, Genome Building Rm 3503, Davis, CA, 95616-8636, USA
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84
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Shattock MJ, Ottolia M, Bers DM, Blaustein MP, Boguslavskyi A, Bossuyt J, Bridge JHB, Chen-Izu Y, Clancy CE, Edwards A, Goldhaber J, Kaplan J, Lingrel JB, Pavlovic D, Philipson K, Sipido KR, Xie ZJ. Na+/Ca2+ exchange and Na+/K+-ATPase in the heart. J Physiol 2015; 593:1361-82. [PMID: 25772291 PMCID: PMC4376416 DOI: 10.1113/jphysiol.2014.282319] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/30/2014] [Indexed: 12/17/2022] Open
Abstract
This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field.
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Affiliation(s)
- Michael J Shattock
- King's College London BHF Centre of Excellence, The Rayne Institute, St Thomas' Hospital, London, SE1 7EH, UK
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85
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Bers DM, Chen-Izu Y. Sodium and calcium regulation in cardiac myocytes: from molecules to heart failure and arrhythmia. J Physiol 2015; 593:1327-9. [PMID: 25772288 DOI: 10.1113/jp270133] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
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86
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Effect of α-Allocryptopine on Delayed Afterdepolarizations and Triggered Activities in Mice Cardiomyocytes Treated with Isoproterenol. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:634172. [PMID: 26557861 PMCID: PMC4629026 DOI: 10.1155/2015/634172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/07/2015] [Accepted: 08/13/2015] [Indexed: 12/16/2022]
Abstract
Objective. To investigate the effect of α-allocryptopine (ALL) on delayed afterdepolarization (DAD) incidence and triggered activity (TA) in mice administered isoproterenol (ISO). Methods. Mouse ventricular myocytes were isolated. And the cellular electrophysiological properties of ventricular myocytes were investigated. Results. We found that the incidences of DADs and TA in mouse myocytes were increased by ISO treatment. In sharp contrast, triggered arrhythmia events were rarely observed in myocytes with 10 μM ALL treatment. Transient inward current (I ti) was reduced significantly with ALL treatment, which contributed to DAD-related triggered arrhythmia. Compared to Iso-treated group, the L-type calcium current (I Ca,L) densities were decreased after exposure to ALL, along with slower activation, quicker inactivation, and longer time constant of recovery from inactivation kinetics. Conclusion. There is less triggered arrhythmia events in ventricular myocytes treated with ALL. This effect may be associated with the inhibition of I ti and I Ca,L.
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87
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Gomez JF, Cardona K, Trenor B. Lessons learned from multi-scale modeling of the failing heart. J Mol Cell Cardiol 2015; 89:146-59. [PMID: 26476237 DOI: 10.1016/j.yjmcc.2015.10.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/07/2015] [Accepted: 10/14/2015] [Indexed: 12/26/2022]
Abstract
Heart failure constitutes a major public health problem worldwide. Affected patients experience a number of changes in the electrical function of the heart that predispose to potentially lethal cardiac arrhythmias. Due to the multitude of electrophysiological changes that may occur during heart failure, the scientific literature is complex and sometimes ambiguous, perhaps because these findings are highly dependent on the etiology, the stage of heart failure, and the experimental model used to study these changes. Nevertheless, a number of common features of failing hearts have been documented. Prolongation of the action potential (AP) involving ion channel remodeling and alterations in calcium handling have been established as the hallmark characteristics of myocytes isolated from failing hearts. Intercellular uncoupling and fibrosis are identified as major arrhythmogenic factors. Multi-scale computational simulations are a powerful tool that complements experimental and clinical research. The development of biophysically detailed computer models of single myocytes and cardiac tissues has contributed greatly to our understanding of processes underlying excitation and repolarization in the heart. The electrical, structural, and metabolic remodeling that arises in cardiac tissues during heart failure has been addressed from different computational perspectives to further understand the arrhythmogenic substrate. This review summarizes the contributions from computational modeling and simulation to predict the underlying mechanisms of heart failure phenotypes and their implications for arrhythmogenesis, ranging from the cellular level to whole-heart simulations. The main aspects of heart failure are presented in several related sections. An overview of the main electrophysiological and structural changes that have been observed experimentally in failing hearts is followed by the description and discussion of the simulation work in this field at the cellular level, and then in 2D and 3D cardiac structures. The implications for arrhythmogenesis in heart failure are also discussed including therapeutic measures, such as drug effects and cardiac resynchronization therapy. Finally, the future challenges in heart failure modeling and simulation will be discussed.
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Affiliation(s)
- Juan F Gomez
- Instituto de Investigación Interuniversitario en Bioingeniería y Tecnología Orientada, al Ser Humano (I3BH), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
| | - Karen Cardona
- Instituto de Investigación Interuniversitario en Bioingeniería y Tecnología Orientada, al Ser Humano (I3BH), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
| | - Beatriz Trenor
- Instituto de Investigación Interuniversitario en Bioingeniería y Tecnología Orientada, al Ser Humano (I3BH), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
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88
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Schüler C, Fischer E, Shaltiel L, Steuer Costa W, Gottschalk A. Arrhythmogenic effects of mutated L-type Ca 2+-channels on an optogenetically paced muscular pump in Caenorhabditis elegans. Sci Rep 2015; 5:14427. [PMID: 26399900 PMCID: PMC4585839 DOI: 10.1038/srep14427] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/28/2015] [Indexed: 01/23/2023] Open
Abstract
Cardiac arrhythmias are often associated with mutations in ion channels or other proteins. To enable drug development for distinct arrhythmias, model systems are required that allow implementing patient-specific mutations. We assessed a muscular pump in Caenorhabditis elegans. The pharynx utilizes homologues of most of the ion channels, pumps and transporters defining human cardiac physiology. To yield precise rhythmicity, we optically paced the pharynx using channelrhodopsin-2. We assessed pharynx pumping by extracellular recordings (electropharyngeograms—EPGs), and by a novel video-microscopy based method we developed, which allows analyzing multiple animals simultaneously. Mutations in the L-type VGCC (voltage-gated Ca2+-channel) EGL-19 caused prolonged pump duration, as found for analogous mutations in the Cav1.2 channel, associated with long QT syndrome. egl-19 mutations affected ability to pump at high frequency and induced arrhythmicity. The pharyngeal neurons did not influence these effects. We tested whether drugs could ameliorate arrhythmia in the optogenetically paced pharynx. The dihydropyridine analog Nemadipine A prolonged pump duration in wild type, and reduced or prolonged pump duration of distinct egl-19 alleles, thus indicating allele-specific effects. In sum, our model may allow screening of drug candidates affecting specific VGCCs mutations, and permit to better understand the effects of distinct mutations on a macroscopic level.
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Affiliation(s)
- Christina Schüler
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany.,Cluster of Excellence Frankfurt-Macromolecular Complexes, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany
| | - Elisabeth Fischer
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany.,Cluster of Excellence Frankfurt-Macromolecular Complexes, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany
| | - Lior Shaltiel
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany
| | - Wagner Steuer Costa
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany.,Cluster of Excellence Frankfurt-Macromolecular Complexes, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany
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89
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Lambert R, Srodulski S, Peng X, Margulies KB, Despa F, Despa S. Intracellular Na+ Concentration ([Na+]i) Is Elevated in Diabetic Hearts Due to Enhanced Na+-Glucose Cotransport. J Am Heart Assoc 2015; 4:e002183. [PMID: 26316524 PMCID: PMC4599504 DOI: 10.1161/jaha.115.002183] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background Intracellular Na+ concentration ([Na+]i) regulates Ca2+ cycling, contractility, metabolism, and electrical stability of the heart. [Na+]i is elevated in heart failure, leading to arrhythmias and oxidative stress. We hypothesized that myocyte [Na+]i is also increased in type 2 diabetes (T2D) due to enhanced activity of the Na+–glucose cotransporter. Methods and Results To test this hypothesis, we used myocardial tissue from humans with T2D and a rat model of late-onset T2D (HIP rat). Western blot analysis showed increased Na+–glucose cotransporter expression in failing hearts from T2D patients compared with nondiabetic persons (by 73±13%) and in HIP rat hearts versus wild-type (WT) littermates (by 61±8%). [Na+]i was elevated in HIP rat myocytes both at rest (14.7±0.9 versus 11.4±0.7 mmol/L in WT) and during electrical stimulation (17.3±0.8 versus 15.0±0.7 mmol/L); however, the Na+/K+-pump function was similar in HIP and WT cells, suggesting that higher [Na+]i is due to enhanced Na+ entry in diabetic hearts. Indeed, Na+ influx was significantly larger in myocytes from HIP versus WT rats (1.77±0.11 versus 1.29±0.06 mmol/L per minute). Na+–glucose cotransporter inhibition with phlorizin or glucose-free solution greatly reduced Na+ influx in HIP myocytes (to 1.20±0.16 mmol/L per minute), whereas it had no effect in WT cells. Phlorizin also significantly decreased glucose uptake in HIP myocytes (by 33±9%) but not in WT, indicating an increased reliance on the Na+–glucose cotransporter for glucose uptake in T2D hearts. Conclusions Myocyte Na+–glucose cotransport is enhanced in T2D, which increases Na+ influx and causes Na+ overload. Higher [Na+]i may contribute to arrhythmogenesis and oxidative stress in diabetic hearts.
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Affiliation(s)
- Rebekah Lambert
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY (R.L., S.S., X.P., F.D., S.D.)
| | - Sarah Srodulski
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY (R.L., S.S., X.P., F.D., S.D.)
| | - Xiaoli Peng
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY (R.L., S.S., X.P., F.D., S.D.)
| | - Kenneth B Margulies
- Cardiovascular Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA (K.B.M.)
| | - Florin Despa
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY (R.L., S.S., X.P., F.D., S.D.)
| | - Sanda Despa
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY (R.L., S.S., X.P., F.D., S.D.)
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90
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Johnston AS, Lehnart SE, Burgoyne JR. Ca(2+) signaling in the myocardium by (redox) regulation of PKA/CaMKII. Front Pharmacol 2015; 6:166. [PMID: 26321952 PMCID: PMC4530260 DOI: 10.3389/fphar.2015.00166] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/24/2015] [Indexed: 12/21/2022] Open
Abstract
Homeostatic cardiac function is maintained by a complex network of interdependent signaling pathways which become compromised during disease progression. Excitation-contraction-coupling, the translation of an electrical signal to a contractile response is critically dependent on a tightly controlled sequence of events culminating in a rise in intracellular Ca(2+) and subsequent contraction of the myocardium. Dysregulation of this Ca(2+) handling system as well as increases in the production of reactive oxygen species (ROS) are two major contributing factors to myocardial disease progression. ROS, generated by cellular oxidases and by-products of cellular metabolism, are highly reactive oxygen derivatives that function as key secondary messengers within the heart and contribute to normal homeostatic function. However, excessive production of ROS, as in disease, can directly interact with kinases critical for Ca(2+) regulation. This post-translational oxidative modification therefore links changes in the redox status of the myocardium to phospho-regulated pathways essential for its function. This review aims to describe the oxidative regulation of the Ca(2+)/calmodulin-dependent kinase II (CaMKII) and cAMP-dependent protein kinase A (PKA), and the subsequent impact this has on Ca(2+) handling within the myocardium. Elucidating the impact of alterations in intracellular ROS production on Ca(2+) dynamics through oxidative modification of key ROS sensing kinases, may provide novel therapeutic targets for preventing myocardial disease progression.
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Affiliation(s)
- Alex S Johnston
- Heart Research Center Goettingen, Clinic of Cardiology and Pulmonology, University Medical Center Goettingen Goettingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Goettingen, Clinic of Cardiology and Pulmonology, University Medical Center Goettingen Goettingen, Germany ; German Center for Cardiovascular Research (DZHK) site Göttingen Berlin, Germany
| | - Joseph R Burgoyne
- Cardiovascular Division, The British Heart Foundation Centre of Excellence, The Rayne Institute, King's College London, St. Thomas' Hospital London, UK
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91
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Eykyn TR, Aksentijević D, Aughton KL, Southworth R, Fuller W, Shattock MJ. Multiple quantum filtered (23)Na NMR in the Langendorff perfused mouse heart: Ratio of triple/double quantum filtered signals correlates with [Na]i. J Mol Cell Cardiol 2015. [PMID: 26196304 PMCID: PMC4564289 DOI: 10.1016/j.yjmcc.2015.07.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We investigate the potential of multiple quantum filtered (MQF) 23Na NMR to probe intracellular [Na]i in the Langendorff perfused mouse heart. In the presence of Tm(DOTP) shift reagent the triple quantum filtered (TQF) signal originated largely from the intracellular sodium pool with a 32 ± 6% contribution of the total TQF signal arising from extracellular sodium, whilst the rank 2 double-quantum filtered signal (DQF), acquired with a 54.7° flip-angle pulse, originated exclusively from the extracellular sodium pool. Given the different cellular origins of the 23Na MQF signals we propose that the TQF/DQF ratio can be used as a semi-quantitative measure of [Na]i in the mouse heart. We demonstrate a good correlation of this ratio with [Na]i measured with shift reagent at baseline and under conditions of elevated [Na]i. We compare the measurements of [Na]i using both shift reagent and TQF/DQF ratio in a cohort of wild type mouse hearts and in a transgenic PLM3SA mouse expressing a non-phosphorylatable form of phospholemman, showing a modest but measurable elevation of baseline [Na]i. MQF filtered 23Na NMR is a potentially useful tool for studying normal and pathophysiological changes in [Na]i, particularly in transgenic mouse models with altered Na regulation. Intracellular Na concentration [Na]i is a key modulator of cardiac cell function. We developed an NMR-compatible Langendorff mouse heart perfusion system. The ratio of triple/double quantum filtered 23Na NMR signals correlates with [Na]i. Intracellular [Na]i can be quantified under physiological perfusion conditions. The PLM3SA transgenic mouse model has a measurable elevation of [Na]i at baseline.
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Affiliation(s)
- Thomas R Eykyn
- Department of Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London SE1 7EH, United Kingdom; The British Heart Foundation Centre of Research Excellence, The Rayne Institute, King's College London, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
| | - Dunja Aksentijević
- The British Heart Foundation Centre of Research Excellence, The Rayne Institute, King's College London, St. Thomas' Hospital, London SE1 7EH, United Kingdom
| | - Karen L Aughton
- The British Heart Foundation Centre of Research Excellence, The Rayne Institute, King's College London, St. Thomas' Hospital, London SE1 7EH, United Kingdom
| | - Richard Southworth
- Department of Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London SE1 7EH, United Kingdom; The British Heart Foundation Centre of Research Excellence, The Rayne Institute, King's College London, St. Thomas' Hospital, London SE1 7EH, United Kingdom
| | - William Fuller
- Division of Cardiovascular and Diabetes Medicine, University of Dundee, Dundee, United Kingdom
| | - Michael J Shattock
- The British Heart Foundation Centre of Research Excellence, The Rayne Institute, King's College London, St. Thomas' Hospital, London SE1 7EH, United Kingdom
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92
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Münzel T, Gori T, Keaney JF, Maack C, Daiber A. Pathophysiological role of oxidative stress in systolic and diastolic heart failure and its therapeutic implications. Eur Heart J 2015; 36:2555-64. [PMID: 26142467 DOI: 10.1093/eurheartj/ehv305] [Citation(s) in RCA: 255] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/15/2015] [Indexed: 02/07/2023] Open
Abstract
Systolic and diastolic myocardial dysfunction has been demonstrated to be associated with an activation of the circulating and local renin-angiotensin-aldosterone system (RAAS), and with a subsequent inappropriately increased production of reactive oxygen species (ROS). While, at low concentrations, ROS modulate important physiological functions through changes in cellular signalling and gene expression, overproduction of ROS may adversely alter cardiac mechanics, leading to further worsening of systolic and diastolic function. In addition, vascular endothelial dysfunction due to uncoupling of the nitric oxide synthase, activation of vascular and phagocytic membrane oxidases or mitochondrial oxidative stress may lead to increased vascular stiffness, further compromising cardiac performance in afterload-dependent hearts. In the present review, we address the potential role of ROS in the pathophysiology of myocardial and vascular dysfunction in heart failure (HF) and their therapeutic targeting. We discuss possible mechanisms underlying the failure of antioxidant vitamins in improving patients' prognosis, the impact of angiotensin-converting enzyme inhibitors or AT1 receptor blockers on oxidative stress, and the mechanism of the benefit of combination of hydralazine/isosorbide dinitrate. Further, we provide evidence supporting the existence of differences in the pathophysiology of HF with preserved vs. reduced ejection fraction and whether targeting mitochondrial ROS might be a particularly interesting therapeutic option for patients with preserved ejection fraction.
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Affiliation(s)
- Thomas Münzel
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Langenbeckstrasse 1, Mainz 55131, Germany
| | - Tommaso Gori
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Langenbeckstrasse 1, Mainz 55131, Germany
| | - John F Keaney
- University of Massachusetts Medical School, Worcester, MA, USA
| | - Christoph Maack
- Klinik für Innere Medizin III Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Andreas Daiber
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Langenbeckstrasse 1, Mainz 55131, Germany
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93
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Poulet C, Wettwer E, Grunnet M, Jespersen T, Fabritz L, Matschke K, Knaut M, Ravens U. Late Sodium Current in Human Atrial Cardiomyocytes from Patients in Sinus Rhythm and Atrial Fibrillation. PLoS One 2015; 10:e0131432. [PMID: 26121051 PMCID: PMC4485891 DOI: 10.1371/journal.pone.0131432] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/01/2015] [Indexed: 12/19/2022] Open
Abstract
Slowly inactivating Na+ channels conducting “late” Na+ current (INa,late) contribute to ventricular arrhythmogenesis under pathological conditions. INa,late was also reported to play a role in chronic atrial fibrillation (AF). The objective of this study was to investigate INa,late in human right atrial cardiomyocytes as a putative drug target for treatment of AF. To activate Na+ channels, cardiomyocytes from transgenic mice which exhibit INa,late (ΔKPQ), and right atrial cardiomyocytes from patients in sinus rhythm (SR) and AF were voltage clamped at room temperature by 250-ms long test pulses to -30 mV from a holding potential of -80 mV with a 100-ms pre-pulse to -110 mV (protocol I). INa,late at -30 mV was not discernible as deviation from the extrapolated straight line IV-curve between -110 mV and -80 mV in human atrial cells. Therefore, tetrodotoxin (TTX, 10 μM) was used to define persistent inward current after 250 ms at -30 mV as INa,late. TTX-sensitive current was 0.27±0.06 pA/pF in ventricular cardiomyocytes from ΔKPQ mice, and amounted to 0.04±0.01 pA/pF and 0.09±0.02 pA/pF in SR and AF human atrial cardiomyocytes, respectively. With protocol II (holding potential -120 mV, pre-pulse to -80 mV) TTX-sensitive INa,late was always larger than with protocol I. Ranolazine (30 μM) reduced INa,late by 0.02±0.02 pA/pF in SR and 0.09±0.02 pA/pF in AF cells. At physiological temperature (37°C), however, INa,late became insignificant. Plateau phase and upstroke velocity of action potentials (APs) recorded with sharp microelectrodes in intact human trabeculae were more sensitive to ranolazine in AF than in SR preparations. Sodium channel subunits expression measured with qPCR was high for SCN5A with no difference between SR and AF. Expression of SCN8A and SCN10A was low in general, and lower in AF than in SR. In conclusion, We confirm for the first time a TTX-sensitive current (INa,late) in right atrial cardiomyocytes from SR and AF patients at room temperature, but not at physiological temperature. While our study provides evidence for the presence of INa,late in human atria, the potential of such current as a target for the treatment of AF remains to be demonstrated.
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Affiliation(s)
- Claire Poulet
- Department of Pharmacology and Toxicology, Medical Faculty, TU Dresden, Dresden, Germany
| | - Erich Wettwer
- Department of Pharmacology and Toxicology, Medical Faculty, TU Dresden, Dresden, Germany
| | - Morten Grunnet
- Danish Arrhythmia Research Centre, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Danish Arrhythmia Research Centre, University of Copenhagen, Copenhagen, Denmark
| | - Larissa Fabritz
- Centre for Cardiovascular Sciences, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Klaus Matschke
- Clinic for Cardiac Surgery, Heart Center Dresden, Dresden, Germanymailto
| | - Michael Knaut
- Clinic for Cardiac Surgery, Heart Center Dresden, Dresden, Germanymailto
| | - Ursula Ravens
- Department of Pharmacology and Toxicology, Medical Faculty, TU Dresden, Dresden, Germany
- * E-mail:
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94
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Gintant G. Cardiac Sodium Current (Na v1.5). METHODS AND PRINCIPLES IN MEDICINAL CHEMISTRY 2015. [DOI: 10.1002/9783527673643.ch12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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95
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Zhao C, Wang L, Ma X, Zhu W, Yao L, Cui Y, Liu Y, Li J, Liang X, Sun Y, Li L, Chen YH. Cardiac Nav 1.5 is modulated by ubiquitin protein ligase E3 component n-recognin UBR3 and 6. J Cell Mol Med 2015; 19:2143-52. [PMID: 26059563 PMCID: PMC4568919 DOI: 10.1111/jcmm.12588] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/03/2015] [Indexed: 11/29/2022] Open
Abstract
The voltage-gated Na+ channel Nav1.5 is essential for action potential (AP) formation and electrophysiological homoeostasis in the heart. The ubiquitin–proteasome system (UPS) is a major degradative system for intracellular proteins including ion channels. The ubiquitin protein ligase E3 component N-recognin (UBR) family is a part of the UPS; however, their roles in regulating cardiac Nav1.5 channels remain elusive. Here, we found that all of the UBR members were expressed in cardiomyocytes. Individual knockdown of UBR3 or UBR6, but not of other UBR members, significantly increased Nav1.5 protein levels in neonatal rat ventricular myocytes, and this effect was verified in HEK293T cells expressing Nav1.5 channels. The UBR3/6-dependent regulation of Nav1.5 channels was not transcriptionally mediated, and pharmacological inhibition of protein biosynthesis failed to counteract the increase in Nav1.5 protein caused by UBR3/6 reduction, suggesting a degradative modulation of UBR3/6 on Nav1.5. Furthermore, the effects of UBR3/6 knockdown on Nav1.5 proteins were abolished under the inhibition of proteasome activity, and UBR3/6 knockdown reduced Nav1.5 ubiquitylation. The double UBR3–UBR6 knockdown resulted in comparable increases in Nav1.5 proteins to that observed for single knockdown of either UBR3 or UBR6. Electrophysiological recordings showed that UBR3/6 reduction-mediated increase in Nav1.5 protein enhanced the opening of Nav1.5 channels and thereby the amplitude of the AP. Thus, our findings indicate that UBR3/6 regulate cardiomyocyte Nav1.5 channel protein levels via the ubiquitin–proteasome pathway. It is likely that UBR3/6 have the potential to be a therapeutic target for cardiac arrhythmias.
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Affiliation(s)
- Chunxia Zhao
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lijie Wang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiue Ma
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Weidong Zhu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Lei Yao
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China
| | - Yingyu Cui
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Yi Liu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Jun Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Xingqun Liang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Yunfu Sun
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Li Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Yi-Han Chen
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
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96
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Zhou JJ, Ma HJ, Liu Y, Guan Y, Maslov LN, Li DP, Zhang Y. The anti-arrhythmic effect of chronic intermittent hypobaric hypoxia in rats with metabolic syndrome induced with fructose. Can J Physiol Pharmacol 2015; 93:227-32. [DOI: 10.1139/cjpp-2014-0343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This study investigated the anti-arrhythmic effects from chronic intermittent hypobaric hypoxia (CIHH) and the cellular mechanisms in rats with metabolic syndrome. Male Sprague–Dawley rats were randomly distributed among the control, fructose-fed (fed with 10% fructose in the drinking water to induce metabolic syndrome), CIHH (42 days of hypobaric hypoxia treatment simulating an altitude of 5000 m a.s.l.: PB = 404 mm Hg, PO2 = 84 mm Hg, 6 h per day), and the CIHH plus fructose (CIHH-F) groups. In anesthetized rats, the arrhythmia score was determined after 30 min of cardiac ischemia followed by 120 min of reperfusion. Action potentials (AP) were recorded from isolated ventricular papillary muscles. The arrhythmia score was much lower in CIHH-F rats than in the fructose-fed rats. Under basic conditions, AP duration (APD) was significantly shortened in fructose-fed rats, but obviously prolonged in CIHH rats compared with that of the control rats. During ischemia, the AP amplitude, the maximal rate of rise of phase 0, APD, and resting potential, were lower in the control, fructose-fed, and CIHH-F groups, but were not changed in the CIHH rats. The lower AP during ischemia did not recover after washout for the fructose-fed rats. In conclusion, CIHH protects the heart against ischemia–reperfusion induced arrhythmia in rats with metabolic syndrome. This effect of CIHH is possibly related to baseline prolongation of the AP and attenuation of AP reduction during ischemia–reperfusion.
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Affiliation(s)
- Jing-Jing Zhou
- Department of Physiology, Hebei Medical University, Shijiazhuang 050017, China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, Hebei 050000, P.R. China
| | - Hui-Jie Ma
- Department of Physiology, Hebei Medical University, Shijiazhuang 050017, China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, Hebei 050000, P.R. China
| | - Yan Liu
- Department of Endocrinology, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei 050051, P.R. China
| | - Yue Guan
- Department of Physiology, Hebei Medical University, Shijiazhuang 050017, China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, Hebei 050000, P.R. China
| | - Leonid N. Maslov
- Institute of Cardiology of the Siberian Branch of the Russian Academy of Medical Sciences, Tomsk 634012, Russia
| | - De-Pei Li
- Department of Critical Care, The University of Texas, M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang 050017, China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, Hebei 050000, P.R. China
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97
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Uryash A, Bassuk J, Kurlansky P, Altamirano F, Lopez JR, Adams JA. Non-invasive technology that improves cardiac function after experimental myocardial infarction: Whole Body Periodic Acceleration (pGz). PLoS One 2015; 10:e0121069. [PMID: 25807532 PMCID: PMC4373845 DOI: 10.1371/journal.pone.0121069] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/27/2015] [Indexed: 01/04/2023] Open
Abstract
Myocardial infarction (MI) may produce significant inflammatory changes and adverse ventricular remodeling leading to heart failure and premature death. Pharmacologic, stem cell transplantation, and exercise have not halted the inexorable rise in the prevalence and great economic costs of heart failure despite extensive investigations of such treatments. New therapeutic modalities are needed. Whole Body Periodic Acceleration (pGz) is a non-invasive technology that increases pulsatile shear stress to the endothelium thereby producing several beneficial cardiovascular effects as demonstrated in animal models, normal humans and patients with heart disease. pGz upregulates endothelial derived nitric oxide synthase (eNOS) and its phosphorylation (p-eNOS) to improve myocardial function in models of myocardial stunning and preconditioning. Here we test whether pGz applied chronically after focal myocardial infarction in rats improves functional outcomes from MI. Focal MI was produced by left coronary artery ligation. One day after ligation animals were randomized to receive daily treatments of pGz for four weeks (MI-pGz) or serve as controls (MI-CONT), with an additional group as non-infarction controls (Sham). Echocardiograms and invasive pressure volume loop analysis were carried out. Infarct transmurality, myocardial fibrosis, and markers of inflammatory and anti-inflammatory cytokines were determined along with protein analysis of eNOS, p-eNOS and inducible nitric oxide synthase (iNOS).At four weeks, survival was 80% in MI-pGz vs 50% in MI-CONT (p< 0.01). Ejection fraction and fractional shortening and invasive pressure volume relation indices of afterload and contractility were significantly better in MI-pGz. The latter where associated with decreased infarct transmurality and decreased fibrosis along with increased eNOS, p-eNOS. Additionally, MI-pGz had significantly lower levels of iNOS, inflammatory cytokines (IL-6, TNF-α), and higher level of anti-inflammatory cytokine (IL-10). pGz improved survival and contractile performance, associated with improved myocardial remodeling. pGz may serve as a simple, safe, non-invasive therapeutic modality to improve myocardial function after MI.
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Affiliation(s)
- Arkady Uryash
- Division of Neonatology, Mount Sinai Medical Center, Miami Beach, FL, United States of America
| | - Jorge Bassuk
- Division of Neonatology, Mount Sinai Medical Center, Miami Beach, FL, United States of America
| | - Paul Kurlansky
- Columbia Heart Source, Columbia University College of Physicians and Surgeons, New York, NY, United States of America
| | - Francisco Altamirano
- Departments of Molecular Bioscience, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Jose R. Lopez
- Departments of Molecular Bioscience, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Jose A. Adams
- Division of Neonatology, Mount Sinai Medical Center, Miami Beach, FL, United States of America
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98
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Ziolo MT, Houser SR. Abnormal Ca(2+) cycling in failing ventricular myocytes: role of NOS1-mediated nitroso-redox balance. Antioxid Redox Signal 2014; 21:2044-59. [PMID: 24801117 PMCID: PMC4208612 DOI: 10.1089/ars.2014.5873] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
SIGNIFICANCE Heart failure (HF) results from poor heart function and is the leading cause of death in Western society. Abnormalities of Ca(2+) handling at the level of the ventricular myocyte are largely responsible for much of the poor heart function. RECENT ADVANCES Although studies have unraveled numerous mechanisms for the abnormal Ca(2+) handling, investigations over the past decade have indicated that much of the contractile dysfunction and adverse remodeling that occurs in HF involves oxidative stress. CRITICAL ISSUES Regrettably, antioxidant therapy has been an immense disappointment in clinical trials. Thus, redox signaling is being reassessed to elucidate why antioxidants failed to treat HF. FUTURE DIRECTIONS A recently identified aspect of redox signaling (specifically the superoxide anion radical) is its interaction with nitric oxide, known as the nitroso-redox balance. There is a large nitroso-redox imbalance with HF, and we suggest that correcting this imbalance may be able to restore myocyte contraction and improve heart function.
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Affiliation(s)
- Mark T Ziolo
- 1 Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University , Columbus, Ohio
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99
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Knez J, Salvi E, Tikhonoff V, Stolarz-Skrzypek K, Ryabikov A, Thijs L, Braga D, Kloch-Badelek M, Malyutina S, Casiglia E, Czarnecka D, Kawecka-Jaszcz K, Cusi D, Nawrot T, Staessen JA, Kuznetsova T. Left ventricular diastolic function associated with common genetic variation in ATP12A in a general population. BMC MEDICAL GENETICS 2014; 15:121. [PMID: 25366262 PMCID: PMC4411923 DOI: 10.1186/s12881-014-0121-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/22/2014] [Indexed: 01/28/2023]
Abstract
Background Left ventricular (LV) function depends on the activity of transmembrane electrolyte transporters. Failing human myocardium has lower Na+/K+ ATPase expression and higher intracellular sodium concentrations. The ATP12A gene encodes a catalytic subunit of an ATPase that can function as a Na+/K+ pump. We, therefore, investigated the association between LV function and common genetic variants in ATP12A. Methods A random sample of 1166 participants (53.7% women; mean age 49.5 years, 44.8% hypertensive) was recruited in Belgium, Poland, Italy and Russia. We measured transmitral early and late diastolic velocities (E and A) by pulsed wave Doppler, and mitral annular velocities (e’ and a’) by tissue Doppler. Using principal component analysis, we summarized 7 Doppler indexes – namely, E, A, e’ and a’ velocities, and their ratios (E/A, e’/a’, and E/e’) – into a single diastolic score. We genotyped 5 tag SNPs (rs963984, rs9553395, rs10507337, rs12872010, rs2071490) in ATP12A. In our analysis we focused on rs10507337 because it is located within a transcription factor binding site. Results In the population-based analyses while adjusting for covariables and accounting for family clusters and country, rs10507337 C allele carriers had significantly higher E/A (P = 0.003), e’ (P = 5.8×10−5), e’/a’ (P = 0.003) and diastolic score (P = 0.0001) compared to TT homozygotes. Our findings were confirmed in the haplotype analysis and in the family-based analyses in 74 informative offspring. Conclusions LV diastolic function as assessed by conventional and tissue Doppler indexes including a composite diastolic score was associated with genetic variation in ATP12A. Further experimental studies are necessary to clarify the role of ATP12A in myocardial relaxation. Electronic supplementary material The online version of this article (doi:10.1186/s12881-014-0121-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Judita Knez
- KU Leuven Department of Cardiovascular Sciences, Research Unit Hypertension and Cardiovascular Epidemiology, University of Leuven, Leuven, Belgium. .,Hypertension Division, Department of Internal Medicine, University Clinical Centre Ljubljana, Ljubljana, Slovenia.
| | - Erika Salvi
- Department of Health, University of Milano and Genomics and Bioinformatics Platform, Fondazione Filarete, Milano, Italy.
| | - Valérie Tikhonoff
- Department of Medicine, University of Padova, Padova, Italy. .,MRC Unit for Lifelong Health and Ageing at University College London, London, UK.
| | - Katarzyna Stolarz-Skrzypek
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University Medical College, Krakow, Poland.
| | - Andrew Ryabikov
- Institute of Internal and Preventive Medicine, Novosibirsk, Russian Federation. .,Novosibirsk State Medical University, Novosibirsk, Russian Federation.
| | - Lutgarde Thijs
- KU Leuven Department of Cardiovascular Sciences, Research Unit Hypertension and Cardiovascular Epidemiology, University of Leuven, Leuven, Belgium.
| | - Daniele Braga
- Department of Health, University of Milano and Genomics and Bioinformatics Platform, Fondazione Filarete, Milano, Italy.
| | - Malgorzata Kloch-Badelek
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University Medical College, Krakow, Poland.
| | - Sofia Malyutina
- Institute of Internal and Preventive Medicine, Novosibirsk, Russian Federation. .,Novosibirsk State Medical University, Novosibirsk, Russian Federation.
| | | | - Danuta Czarnecka
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University Medical College, Krakow, Poland.
| | - Kalina Kawecka-Jaszcz
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University Medical College, Krakow, Poland.
| | - Daniele Cusi
- Department of Health, University of Milano and Genomics and Bioinformatics Platform, Fondazione Filarete, Milano, Italy.
| | - Tim Nawrot
- Department of Public Health, Occupational and Environmental Medicine, KU Leuven, Leuven, Belgium. .,Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.
| | - Jan A Staessen
- KU Leuven Department of Cardiovascular Sciences, Research Unit Hypertension and Cardiovascular Epidemiology, University of Leuven, Leuven, Belgium. .,Department of Epidemiology, Maastricht University, Maastricht, Netherlands.
| | - Tatiana Kuznetsova
- KU Leuven Department of Cardiovascular Sciences, Research Unit Hypertension and Cardiovascular Epidemiology, University of Leuven, Leuven, Belgium.
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100
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Greiser M, Kerfant BG, Williams GS, Voigt N, Harks E, Dibb KM, Giese A, Meszaros J, Verheule S, Ravens U, Allessie MA, Gammie JS, van der Velden J, Lederer WJ, Dobrev D, Schotten U. Tachycardia-induced silencing of subcellular Ca2+ signaling in atrial myocytes. J Clin Invest 2014; 124:4759-72. [PMID: 25329692 PMCID: PMC4347234 DOI: 10.1172/jci70102] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Accepted: 08/28/2014] [Indexed: 01/06/2023] Open
Abstract
Atrial fibrillation (AF) is characterized by sustained high atrial activation rates and arrhythmogenic cellular Ca2+ signaling instability; however, it is not clear how a high atrial rate and Ca2+ instability may be related. Here, we characterized subcellular Ca2+ signaling after 5 days of high atrial rates in a rabbit model. While some changes were similar to those in persistent AF, we identified a distinct pattern of stabilized subcellular Ca2+ signaling. Ca2+ sparks, arrhythmogenic Ca2+ waves, sarcoplasmic reticulum (SR) Ca2+ leak, and SR Ca2+ content were largely unaltered. Based on computational analysis, these findings were consistent with a higher Ca2+ leak due to PKA-dependent phosphorylation of SR Ca2+ channels (RyR2s), fewer RyR2s, and smaller RyR2 clusters in the SR. We determined that less Ca2+ release per [Ca2+]i transient, increased Ca2+ buffering strength, shortened action potentials, and reduced L-type Ca2+ current contribute to a stunning reduction of intracellular Na+ concentration following rapid atrial pacing. In both patients with AF and in our rabbit model, this silencing led to failed propagation of the [Ca2+]i signal to the myocyte center. We conclude that sustained high atrial rates alone silence Ca2+ signaling and do not produce Ca2+ signaling instability, consistent with an adaptive molecular and cellular response to atrial tachycardia.
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Affiliation(s)
- Maura Greiser
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Benoît-Gilles Kerfant
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - George S.B. Williams
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Niels Voigt
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Erik Harks
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Katharine M. Dibb
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Anne Giese
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Janos Meszaros
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Sander Verheule
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Ursula Ravens
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Maurits A. Allessie
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - James S. Gammie
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - W. Jonathan Lederer
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Dobromir Dobrev
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Ulrich Schotten
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
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