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Lozano O, Marcos P, Salazar-Ramirez FDJ, Lázaro-Alfaro AF, Sobrevia L, García-Rivas G. Targeting the mitochondrial Ca 2+ uniporter complex in cardiovascular disease. Acta Physiol (Oxf) 2023; 237:e13946. [PMID: 36751976 DOI: 10.1111/apha.13946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/09/2023]
Abstract
Cardiovascular diseases (CVDs), the leading cause of death worldwide, share in common mitochondrial dysfunction, in specific a dysregulation of Ca2+ uptake dynamics through the mitochondrial Ca2+ uniporter (MCU) complex. In particular, Ca2+ uptake regulates the mitochondrial ATP production, mitochondrial dynamics, oxidative stress, and cell death. Therefore, modulating the activity of the MCU complex to regulate Ca2+ uptake, has been suggested as a potential therapeutic approach for the treatment of CVDs. Here, the role and implications of the MCU complex in CVDs are presented, followed by a review of the evidence for MCU complex modulation, genetically and pharmacologically. While most approaches have aimed within the MCU complex for the modulation of the Ca2+ pore channel, the MCU subunit, its intra- and extra- mitochondrial implications, including Ca2+ dynamics, oxidative stress, post-translational modifications, and its repercussions in the cardiac function, highlight that targeting the MCU complex has the translational potential for novel CVDs therapeutics.
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Affiliation(s)
- Omar Lozano
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
- Biomedical Research Center, Hospital Zambrano-Hellion, TecSalud, Tecnologico de Monterrey, San Pedro Garza García, Mexico
- The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Mexico
| | - Patricio Marcos
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
| | - Felipe de Jesús Salazar-Ramirez
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
| | - Anay F Lázaro-Alfaro
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
| | - Luis Sobrevia
- The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Mexico
- Cellular and Molecular Physiology Laboratory, Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville, Spain
- University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, Queensland, Australia
| | - Gerardo García-Rivas
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
- Biomedical Research Center, Hospital Zambrano-Hellion, TecSalud, Tecnologico de Monterrey, San Pedro Garza García, Mexico
- The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Mexico
- Center of Functional Medicine, Hospital Zambrano-Hellion, TecSalud, Tecnologico de Monterrey, San Pedro Garza García, Mexico
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Wongtanasarasin W, Siri-Angkul N, Wittayachamnankul B, Chattipakorn SC, Chattipakorn N. Mitochondrial dysfunction in fatal ventricular arrhythmias. Acta Physiol (Oxf) 2021; 231:e13624. [PMID: 33555138 DOI: 10.1111/apha.13624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 02/05/2023]
Abstract
Ventricular fibrillation (VF) and sudden cardiac arrest (SCA) remain some of the most important public health concerns worldwide. For the past 50 years, the recommendation in the Advanced Cardiac Life Support (ACLS) guidelines has been that defibrillation is the only option for shockable cardiac arrest. There is growing evidence to demonstrate that mitochondria play a vital role in the outcome of postresuscitation cardiac function. Although targeting mitochondria to improve resuscitation outcome following cardiac arrest has been proposed for many years, understanding concerning the changes in mitochondria during cardiac arrest, especially in the case of VF, is still limited. In addition, despite new research initiatives and improved medical technology, the overall survival rates of patients with SCA still remain the same. Understanding cardiac mitochondrial alterations during fatal arrhythmias may help to enable the formulation of strategies to improve the outcomes of resuscitation. The attenuation of cardiac mitochondrial dysfunction during VF through pharmacological intervention as well as ischaemic postconditioning could also be a promising target for intervention and inform a new paradigm of treatments. In this review, the existing evidence available from in vitro, ex vivo and in vivo studies regarding the roles of mitochondrial dysfunction during VF is comprehensively summarized and discussed. In addition, the effects of interventions targeting cardiac mitochondria during fatal ventricular arrhythmias are presented. Since there are no clinical reports from studies targeting mitochondria to improve resuscitation outcome available, this review will provide important information to encourage further investigations in a clinical setting.
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Affiliation(s)
- Wachira Wongtanasarasin
- Department of Emergency Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Natthaphat Siri-Angkul
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Borwon Wittayachamnankul
- Department of Emergency Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Njegic A, Wilson C, Cartwright EJ. Targeting Ca 2 + Handling Proteins for the Treatment of Heart Failure and Arrhythmias. Front Physiol 2020; 11:1068. [PMID: 33013458 PMCID: PMC7498719 DOI: 10.3389/fphys.2020.01068] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/04/2020] [Indexed: 12/18/2022] Open
Abstract
Diseases of the heart, such as heart failure and cardiac arrhythmias, are a growing socio-economic burden. Calcium (Ca2+) dysregulation is key hallmark of the failing myocardium and has long been touted as a potential therapeutic target in the treatment of a variety of cardiovascular diseases (CVD). In the heart, Ca2+ is essential for maintaining normal cardiac function through the generation of the cardiac action potential and its involvement in excitation contraction coupling. As such, the proteins which regulate Ca2+ cycling and signaling play a vital role in maintaining Ca2+ homeostasis. Changes to the expression levels and function of Ca2+-channels, pumps and associated intracellular handling proteins contribute to altered Ca2+ homeostasis in CVD. The remodeling of Ca2+-handling proteins therefore results in impaired Ca2+ cycling, Ca2+ leak from the sarcoplasmic reticulum and reduced Ca2+ clearance, all of which contributes to increased intracellular Ca2+. Currently, approved treatments for targeting Ca2+ handling dysfunction in CVD are focused on Ca2+ channel blockers. However, whilst Ca2+ channel blockers have been successful in the treatment of some arrhythmic disorders, they are not universally prescribed to heart failure patients owing to their ability to depress cardiac function. Despite the progress in CVD treatments, there remains a clear need for novel therapeutic approaches which are able to reverse pathophysiology associated with heart failure and arrhythmias. Given that heart failure and cardiac arrhythmias are closely associated with altered Ca2+ homeostasis, this review will address the molecular changes to proteins associated with both Ca2+-handling and -signaling; their potential as novel therapeutic targets will be discussed in the context of pre-clinical and, where available, clinical data.
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Affiliation(s)
- Alexandra Njegic
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom.,Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Claire Wilson
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom.,Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Elizabeth J Cartwright
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom
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4
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5-HTR3 and 5-HTR4 located on the mitochondrial membrane and functionally regulated mitochondrial functions. Sci Rep 2016; 6:37336. [PMID: 27874067 PMCID: PMC5118798 DOI: 10.1038/srep37336] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/25/2016] [Indexed: 11/29/2022] Open
Abstract
5-HT has been reported to possess significant effects on cardiac activities, but activation of 5-HTR on the cell membrane failed to illustrate the controversial cardiac reaction. Because 5-HT constantly comes across the cell membrane via 5-HT transporter (5-HTT) into the cytoplasm, whether 5-HTR is functional present on the cellular organelles is unknown. Here we show 5-HTR3 and 5-HTR4 were located in cardiac mitochondria, and regulated mitochondrial activities and cellular functions. Knock down 5-HTR3 and 5-HTR4 in neonatal cardiomyocytes resulted in significant increase of cell damage in response to hypoxia, and also led to alternation in heart beating. Activation of 5-HTR4 attenuated mitochondrial Ca2+ uptake under the both normoxic and hypoxic conditions, whereas 5-HTR3 augmented Ca2+ uptake only under hypoxia. 5-HTR3 and 5-HTR4 exerted the opposite effects on the mitochondrial respiration: 5-HTR3 increased RCR (respiration control ratio), but 5-HTR4 reduced RCR. Moreover, activation of 5-HTR3 and 5-HTR4 both significantly inhibited the opening of mPTP. Our results provided the first evidence that 5-HTR as a GPCR and an ion channel, functionally expressed in mitochondria and participated in the mitochondria function and regulation to maintain homeostasis of mitochondrial [Ca2+], ROS, and ATP generation efficiency in cardiomyocytes in response to stress and O2 tension.
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Boyman L, Chikando AC, Williams GSB, Khairallah RJ, Kettlewell S, Ward CW, Smith GL, Kao JPY, Lederer WJ. Calcium movement in cardiac mitochondria. Biophys J 2015; 107:1289-301. [PMID: 25229137 DOI: 10.1016/j.bpj.2014.07.045] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/08/2014] [Accepted: 07/22/2014] [Indexed: 10/24/2022] Open
Abstract
Existing theory suggests that mitochondria act as significant, dynamic buffers of cytosolic calcium ([Ca(2+)]i) in heart. These buffers can remove up to one-third of the Ca(2+) that enters the cytosol during the [Ca(2+)]i transients that underlie contractions. However, few quantitative experiments have been presented to test this hypothesis. Here, we investigate the influence of Ca(2+) movement across the inner mitochondrial membrane during both subcellular and global cellular cytosolic Ca(2+) signals (i.e., Ca(2+) sparks and [Ca(2+)]i transients, respectively) in isolated rat cardiomyocytes. By rapidly turning off the mitochondria using depolarization of the inner mitochondrial membrane potential (ΔΨm), the role of the mitochondria in buffering cytosolic Ca(2+) signals was investigated. We show here that rapid loss of ΔΨm leads to no significant changes in cytosolic Ca(2+) signals. Second, we make direct measurements of mitochondrial [Ca(2+)] ([Ca(2+)]m) using a mitochondrially targeted Ca(2+) probe (MityCam) and these data suggest that [Ca(2+)]m is near the [Ca(2+)]i level (∼100 nM) under quiescent conditions. These two findings indicate that although the mitochondrial matrix is fully buffer-capable under quiescent conditions, it does not function as a significant dynamic buffer during physiological Ca(2+) signaling. Finally, quantitative analysis using a computational model of mitochondrial Ca(2+) cycling suggests that mitochondrial Ca(2+) uptake would need to be at least ∼100-fold greater than the current estimates of Ca(2+) influx for mitochondria to influence measurably cytosolic [Ca(2+)] signals under physiological conditions. Combined, these experiments and computational investigations show that mitochondrial Ca(2+) uptake does not significantly alter cytosolic Ca(2+) signals under normal conditions and indicates that mitochondria do not act as important dynamic buffers of [Ca(2+)]i under physiological conditions in heart.
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Affiliation(s)
- Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Aristide C Chikando
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - George S B Williams
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; School of Systems Biology, George Mason University, Fairfax, Virginia
| | - Ramzi J Khairallah
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; University of Maryland School of Nursing, Baltimore, Maryland; Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois
| | - Sarah Kettlewell
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, G12 8QQ Glasgow, United Kingdom
| | - Christopher W Ward
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; University of Maryland School of Nursing, Baltimore, Maryland
| | - Godfrey L Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, G12 8QQ Glasgow, United Kingdom
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland.
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Wolke C, Bukowska A, Goette A, Lendeckel U. Redox control of cardiac remodeling in atrial fibrillation. Biochim Biophys Acta Gen Subj 2014; 1850:1555-65. [PMID: 25513966 DOI: 10.1016/j.bbagen.2014.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a potential cause of thromboembolic events. AF induces significant changes in the electrophysiological properties of atrial myocytes and causes alterations in the structure, metabolism, and function of the atrial tissue. The molecular basis for the development of structural atrial remodeling of fibrillating human atria is still not fully understood. However, increased production of reactive oxygen or nitrogen species (ROS/RNS) and the activation of specific redox-sensitive signaling pathways observed both in patients with and animal models of AF are supposed to contribute to development, progression and self-perpetuation of AF. SCOPE OF REVIEW The present review summarizes the sources and targets of ROS/RNS in the setting of AF and focuses on key redox-sensitive signaling pathways that are implicated in the pathogenesis of AF and function either to aggravate or protect from disease. MAJOR CONCLUSIONS NADPH oxidases and various mitochondrial monooxygenases are major sources of ROS during AF. Besides direct oxidative modification of e.g. ion channels and ion handling proteins that are crucially involved in action potential generation and duration, AF leads to the reversible activation of redox-sensitive signaling pathways mediated by activation of redox-regulated proteins including Nrf2, NF-κB, and CaMKII. Both processes are recognized to contribute to the formation of a substrate for AF and, thus, to increase AF inducibility and duration. GENERAL SIGNIFICANCE AF is a prevalent disease and due to the current demographic developments its socio-economic relevance will further increase. Improving our understanding of the role that ROS and redox-related (patho)-mechanisms play in the development and progression of AF may allow the development of a targeted therapy for AF that surpasses the efficacy of previous general anti-oxidative strategies. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
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Affiliation(s)
- Carmen Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany
| | - Alicja Bukowska
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany
| | - Andreas Goette
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany; Department of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital, D-33098 Paderborn, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany.
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Liu J, Wang P, Zou L, Qu J, Litovsky S, Umeda P, Zhou L, Chatham J, Marsh SA, Dell'Italia LJ, Lloyd SG. High-fat, low-carbohydrate diet promotes arrhythmic death and increases myocardial ischemia-reperfusion injury in rats. Am J Physiol Heart Circ Physiol 2014; 307:H598-608. [PMID: 24929857 DOI: 10.1152/ajpheart.00058.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
High-fat, low-carbohydrate diets (HFLCD) are often eaten by humans for a variety of reasons, but the effects of such diets on the heart are incompletely understood. We evaluated the impact of HFLCD on myocardial ischemia/reperfusion (I/R) using an in vivo model of left anterior descending coronary artery ligation. Sprague-Dawley rats (300 g) were fed HFLCD (60% calories fat, 30% protein, 10% carbohydrate) or control (CONT; 16% fat, 19% protein, 65% carbohydrate) diet for 2 wk and then underwent open chest I/R. At baseline (preischemia), diet did not affect left ventricular (LV) systolic and diastolic function. Oil red O staining revealed presence of lipid in the heart with HFLCD but not in CONT. Following I/R, recovery of LV function was decreased in HFLCD. HFLCD hearts exhibited decreased ATP synthase and increased uncoupling protein-3 gene and protein expression. HFLCD downregulated mitochondrial fusion proteins and upregulated fission proteins and store-operated Ca(2+) channel proteins. HFLCD led to increased death during I/R; 6 of 22 CONT rats and 16 of 26 HFLCD rats died due to ventricular arrhythmias and hemodynamic shock. In surviving rats, HFLCD led to larger infarct size. We concluded that in vivo HFLCD does not affect nonischemic LV function but leads to greater myocardial injury during I/R, with increased risk of death by pump failure and ventricular arrhythmias, which might be associated with altered cardiac energetics, mitochondrial fission/fusion dynamics, and store-operated Ca(2+) channel expression.
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Affiliation(s)
| | - Peipei Wang
- Cardiovascular Research Institute, National University Health System, National University of Singapore, Singapore, Singapore
| | - Luyun Zou
- Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Silvio Litovsky
- Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | | | | | - John Chatham
- Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Susan A Marsh
- Department of Clinical Pharmacology, Washington State University, Pullman, Washington
| | - Louis J Dell'Italia
- Departments of Medicine and Birmingham VA Medical Center, Birmingham, Alabama
| | - Steven G Lloyd
- Departments of Medicine and Birmingham VA Medical Center, Birmingham, Alabama
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The mitochondrial Na+-Ca2+ exchanger, NCLX, regulates automaticity of HL-1 cardiomyocytes. Sci Rep 2013; 3:2766. [PMID: 24067497 PMCID: PMC3783885 DOI: 10.1038/srep02766] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 09/05/2013] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial Ca2+ is known to change dynamically, regulating mitochondrial as well as cellular functions such as energy metabolism and apoptosis. The NCLX gene encodes the mitochondrial Na+-Ca2+ exchanger (NCXmit), a Ca2+ extrusion system in mitochondria. Here we report that the NCLX regulates automaticity of the HL-1 cardiomyocytes. NCLX knockdown using siRNA resulted in the marked prolongation of the cycle length of spontaneous Ca2+ oscillation and action potential generation. The upstrokes of action potential and Ca2+ transient were markedly slower, and sarcoplasmic reticulum (SR) Ca2+ handling were compromised in the NCLX knockdown cells. Analyses using a mathematical model of HL-1 cardiomyocytes demonstrated that blocking NCXmit reduced the SR Ca2+ content to slow spontaneous SR Ca2+ leak, which is a trigger of automaticity. We propose that NCLX is a novel molecule to regulate automaticity of cardiomyocytes via modulating SR Ca2+ handling.
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Akar FG, O'Rourke B. Mitochondria are sources of metabolic sink and arrhythmias. Pharmacol Ther 2011; 131:287-94. [PMID: 21513732 DOI: 10.1016/j.pharmthera.2011.04.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Accepted: 03/29/2011] [Indexed: 12/14/2022]
Abstract
Mitochondria have long been recognized for their central role in energy transduction and apoptosis. More recently, extensive work in multiple laboratories around the world has significantly extended the role of cardiac mitochondria from relatively static arbitrators of cell death and survival pathways to highly dynamic organelles that form interactive functional networks across cardiomyocytes. These coupled networks were shown to strongly affect cardiomyocyte responses to oxidative stress by modulating cell signaling pathways that strongly impact physiological properties. Of particular importance is the role of mitochondria in modulating key electrophysiological and calcium cycling properties in cardiomyocytes, either directly through activation of a myriad of mitochondrial ion channels or indirectly by affecting cell signaling cascades, ATP levels, and the over-all redox state of the cardiomyocyte. This important recognition has ushered a renewed interest in understanding, at a more fundamental level, the exact role that cardiac metabolism, in general and mitochondria, in particular, play in both health and disease. In this article, we provide an overview of recent advances in our growing understanding of the fundamental role that cardiac mitochondria play in the genesis of lethal arrhythmias.
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Affiliation(s)
- Fadi G Akar
- Cardiovascular Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.
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10
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Abstract
Despite a high prevalence of sudden cardiac death throughout the world, the mechanisms that lead to ventricular arrhythmias are not fully understood. Over the last 20 years, a growing body of evidence indicates that cardiac mitochondria are involved in the genesis of arrhythmia. In this review, we have attempted to describe the role that mitochondria play in altering the heart's electrical function by introducing heterogeneity into the cardiac action potential. Specifically, we have focused on how the energetic status of the mitochondrial network can alter sarcolemmal potassium fluxes through ATP-sensitive potassium channels, creating a 'metabolic sink' for depolarizing wave-fronts and introducing conditions that favour catastrophic arrhythmia. Mechanisms by which mitochondria depolarize under conditions of oxidative stress are characterized, and the contributions of several mitochondrial ion channels to mitochondrial depolarization are presented. The inner membrane anion channel in particular opens upstream of other inner membrane channels during metabolic stress, and may be an effective target to prevent the metabolic oscillations that create action potential lability. Finally, we discuss therapeutic strategies that prevent arrhythmias by preserving mitochondrial membrane potential in the face of oxidative stress, supporting the notion that treatments aimed at cardiac mitochondria have significant potential in attenuating electrical dysfunction in the heart.
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Affiliation(s)
- David A Brown
- Department of Physiology, Brody School of Medicine and the East Carolina Heart Institute, East Carolina University, Room 6N-98, 600 Moye Blvd, Greenville, NC 27834, USA.
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11
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Mitochondrial calcium transport in the heart: Physiological and pathological roles. J Mol Cell Cardiol 2009; 46:789-803. [DOI: 10.1016/j.yjmcc.2009.03.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 02/28/2009] [Accepted: 03/03/2009] [Indexed: 12/20/2022]
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12
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Bukowska A, Schild L, Keilhoff G, Hirte D, Neumann M, Gardemann A, Neumann KH, Röhl FW, Huth C, Goette A, Lendeckel U. Mitochondrial dysfunction and redox signaling in atrial tachyarrhythmia. Exp Biol Med (Maywood) 2008; 233:558-74. [PMID: 18375832 DOI: 10.3181/0706-rm-155] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Accumulating evidence links calcium-overload and oxidative stress to atrial remodeling during atrial fibrillation (AF). Furthermore, atrial remodeling appears to increase atrial thrombogeneity, characterized by increased expression of adhesion molecules. The aim of this study was to assess mitochondrial dysfunction and oxidative stress-activated signal transduction (nuclear factor-kappaB [NF-kappa B], lectin-like oxidized low-density lipoprotein receptor [LOX-1], intercellular adhesion molecule-1 [ICAM-1], and hemeoxgenase-1 [HO-1]) in atrial tissue during AF. Ex vivo atrial tissue from patients with and without AF and, additionally, rapid pacing of human atrial tissue slices were used to study mitochondrial structure by electron microscopy and mitochondrial respiration. Furthermore, quantitative reverse transcription polymerase chain reaction (RT-PCR), immunoblot analyses, gel-shift assays, and enzyme-linked immunosorbent assay (ELISA) were applied to measure nuclear amounts of NF-kappa B target gene expression. Using ex vivo atrial tissue samples from patients with AF we demonstrated oxidative stress and impaired mitochondrial structure and respiration, which was accompanied by nuclear accumulation of NF-kappa B and elevated expression levels of the adhesion molecule ICAM-1 and the oxidative stress-induced markers HO-1 and LOX-1. All these changes were reproduced by rapid pacing for 24 hours of human atrial tissue slices. Furthermore, the blockade of calcium inward current with verapamil effectively prevented both the mitochondrial changes and the activation of NF-kappa B signaling and target gene expression. The latter appeared also diminished by the antioxidants apocynin and resveratrol (an inhibitor of NF-kappa B), or the angiotensin II receptor type 1 antagonist, olmesartan. This study demonstrates that calcium inward current via L-type calcium channels contributes to oxidative stress and increased expression of oxidative stress markers and adhesion molecules during cardiac tachyarrhythmia.
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Affiliation(s)
- Alicja Bukowska
- University Hospital Magdeburg, Institute of Experimental Internal Medicine, Leipzigerstrasse 44, 39120 Magdeburg, Germany
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13
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Schild L, Bukowska A, Gardemann A, Polczyk P, Keilhoff G, Täger M, Dudley SC, Klein HU, Goette A, Lendeckel U. Rapid pacing of embryoid bodies impairs mitochondrial ATP synthesis by a calcium-dependent mechanism--a model of in vitro differentiated cardiomyocytes to study molecular effects of tachycardia. Biochim Biophys Acta Mol Basis Dis 2006; 1762:608-15. [PMID: 16644187 PMCID: PMC3153943 DOI: 10.1016/j.bbadis.2006.03.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Revised: 03/17/2006] [Accepted: 03/20/2006] [Indexed: 11/26/2022]
Abstract
Tachycardia may cause substantial molecular and ultrastructural alterations in cardiac tissue. The underlying pathophysiology has not been fully explored. The purpose of this study was (I) to validate a three-dimensional in vitro pacing model, (II) to examine the effect of rapid pacing on mitochondrial function in intact cells, and (III) to evaluate the involvement of L-type-channel-mediated calcium influx in alterations of mitochondria in cardiomyocytes during rapid pacing. In vitro differentiated cardiomyocytes from P19 cells that formed embryoid bodies were paced for 24 h with 0.6 and 2.0 Hz. Pacing at 2.0 Hz increased mRNA expression and phosphorylation of ERK1/2 and caused cellular hypertrophy, indicated by increased protein/DNA ratio, and oxidative stress measured as loss of cellular thiols. Rapid pacing additionally provoked structural alterations of mitochondria. All these changes are known to occur in vivo during atrial fibrillation. The structural alterations of mitochondria were accompanied by limitation of ATP production as evidenced by decreased endogenous respiration in combination with decreased ATP levels in intact cells. Inhibition of calcium inward current with verapamil protected against hypertrophic response and oxidative stress. Verapamil ameliorated morphological changes and dysfunction of mitochondria. In conclusion, rapid pacing-dependent changes in calcium inward current via L-type channels mediate both oxidative stress and mitochondrial dysfunction. The in vitro pacing model presented here reflects changes occurring during tachycardia and, thus, allows functional analyses of the signaling pathways involved.
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Affiliation(s)
- Lorenz Schild
- Institute of Clinical Chemistry, Department of Pathobiochemistry, Otto-von-Guericke University Magdeburg, Germany
| | - Alicja Bukowska
- Institute of Experimental Internal Medicine, Otto-von-Guericke University Magdeburg, Germany
| | - Andreas Gardemann
- Institute of Clinical Chemistry, Department of Pathobiochemistry, Otto-von-Guericke University Magdeburg, Germany
| | - Pamela Polczyk
- Institute of Experimental Internal Medicine, Otto-von-Guericke University Magdeburg, Germany
- Division of Cardiology, University Hospital Magdeburg, Leipzigerstr. 44 39120 Magdeburg, Germany
| | - Gerburg Keilhoff
- Institute of Medical Neurobiology, Otto-von-Guericke University Magdeburg, Germany
| | | | - Samuel C. Dudley
- Division of Cardiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Helmut U. Klein
- Division of Cardiology, University Hospital Magdeburg, Leipzigerstr. 44 39120 Magdeburg, Germany
| | - Andreas Goette
- Division of Cardiology, University Hospital Magdeburg, Leipzigerstr. 44 39120 Magdeburg, Germany
- Corresponding author. Tel.: +49 391 6713203; fax: +49 391 673202. (A. Goette)
| | - Uwe Lendeckel
- Institute of Experimental Internal Medicine, Otto-von-Guericke University Magdeburg, Germany
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Zhang SZ, Gao Q, Cao CM, Bruce IC, Xia Q. Involvement of the mitochondrial calcium uniporter in cardioprotection by ischemic preconditioning. Life Sci 2005; 78:738-45. [PMID: 16150463 DOI: 10.1016/j.lfs.2005.05.076] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Accepted: 05/16/2005] [Indexed: 11/15/2022]
Abstract
The objective of the present study was to determine whether the mitochondrial calcium uniporter plays a role in the cardioprotection induced by ischemic preconditioning (IPC). Isolated rat hearts were subjected to 30 min of regional ischemia by ligation of the left anterior descending artery followed by 120 min of reperfusion. IPC was achieved by two 5-min periods of global ischemia separated by 5 min of reperfusion. IPC reduced the infarct size and lactate dehydrogenase release in coronary effluent, which was associated with improved recovery of left ventricular contractility. Treatment with ruthenium red (RR, 5 microM), an inhibitor of the uniporter, or with Ru360 (10 microM), a highly specific uniporter inhibitor, provided cardioprotective effects like those of IPC. The cardioprotection induced by IPC was abolished by spermine (20 microM), an activator of the uniporter. Cyclosporin A (CsA, 0.2 microM), an inhibitor of the mitochondrial permeability transition pore, reversed the effects caused by spermine. In mitochondria isolated from untreated hearts, both Ru360 (10 microM) and RR (1 microM) decreased pore opening, while spermine (20 microM) increased pore opening which was blocked by CsA (0.2 microM). In mitochondria from preconditioned hearts, the opening of the pore was inhibited, but this inhibition did not occur in the mitochondria from hearts treated with IPC plus spermine. These results indicate that the mitochondrial calcium uniporter is involved in the cardioprotection conferred by ischemic preconditioning.
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Affiliation(s)
- Shi-Zhong Zhang
- Department of Physiology, Zhejiang University School of Medicine, 353 Yan-an Road, Hangzhou 310031, China
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15
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Kimura H, Kawahara K, Yamauchi Y, Miyaki J. On the mechanisms for the conversion of ventricular fibrillation to tachycardia by perfusion with ruthenium red. J Electrocardiol 2005; 38:364-70. [PMID: 16216614 DOI: 10.1016/j.jelectrocard.2005.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 04/24/2005] [Accepted: 05/09/2005] [Indexed: 11/19/2022]
Abstract
We have recently demonstrated that during pacing-induced sustained ventricular fibrillation (VF), perfusion of the heart with either ruthenium red (RR) or Ru 360, blockers of the mitochondrial Ca2+ uniporter, resulted in the reversible conversion of VF to ventricular tachycardia (VT). Here, we aimed at elucidating the electrophysiological mechanisms for the RR-induced conversion of VF to VT. The experiments were performed using Langendorff-perfused isolated rat hearts in which left ventricular pressure and left ventricular intracellular action potential were recorded. Perfusion with either RR or Ru 360 resulted in decreases in the action potential duration (APD), refractory period, and slope of APD restitution curves. These changes were antagonized by cotreatment with S(-)-Bay K8644. In addition, perfusion with verapamil produced the decreases in APD at 90% repolarization, refractory period and slope of APD restitution curves similar to the RR or Ru 360 perfusion. Such electrophysiological changes may be responsible for the reversible conversion of sustained VF to VT caused by perfusion with RR or Ru 360.
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Affiliation(s)
- Hiroyuki Kimura
- Laboratory of Cellular Cybernetics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
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16
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Kawahara K, Takase M, Yamauchi Y, Kimura H. Spectral and correlation analyses of the verapamil-induced conversion of ventricular fibrillation to tachycardia in isolated rat hearts. J Electrocardiol 2004; 37:89-100. [PMID: 15127374 DOI: 10.1016/j.jelectrocard.2004.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Ventricular tachycardia (VT) is considered to be the most common precursor of ventricular fibrillation (VF). However, the mechanisms underlying the transition from VT to VF remain unclear. Here, we investigated whether and how perfusion of the heart with verapamil, a blocker of L-type calcium channels, changed the macro-dynamics of the heart between VT and VF. The experiments were performed with Langendorff perfused isolated rat hearts, in which left ventricular pressure and left ventricular cardiomyogram were measured. Sustained VT or VF was induced by burst pacing of the left ventricular muscles. During sustained VF, verapamil perfusion resulted in the conversion of VF to VT. A cross-correlation analysis between left ventricular cardiomyogram and left ventricular pressure revealed that the correlation coefficient was small during VF, but became larger during VT. This study showed that inactivation of L-type Ca(2+) channels occurred during verapamil-induced conversion of pacing-induced sustained VF to VT, and characterized the changes in macro-dynamics of the heart associated with the transition.
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Affiliation(s)
- Koichi Kawahara
- Laboratory of Biomedical Control, Research Institute for Electronic Science, Hokkaido university, Sapporo, Japan.
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