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Baglini E, Poggetti V, Cavallini C, Petroni D, Forini F, Nicolini G, Barresi E, Salerno S, Costa B, Iozzo P, Neglia D, Menichetti L, Taliani S, Da Settimo F. Targeting the Translocator Protein (18 kDa) in Cardiac Diseases: State of the Art and Future Opportunities. J Med Chem 2024; 67:17-37. [PMID: 38113353 PMCID: PMC10911791 DOI: 10.1021/acs.jmedchem.3c01716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/16/2023] [Accepted: 11/24/2023] [Indexed: 12/21/2023]
Abstract
Mitochondria dysfunctions are typical hallmarks of cardiac disorders (CDs). The multiple tasks of this energy-producing organelle are well documented, but its pathophysiologic involvement in several manifestations of heart diseases, such as altered electromechanical coupling, excitability, and arrhythmias, is still under investigation. The human 18 kDa translocator protein (TSPO) is a protein located on the outer mitochondrial membrane whose expression is altered in different pathological conditions, including CDs, making it an attractive therapeutic and diagnostic target. Currently, only a few TSPO ligands are employed in CDs and cardiac imaging. In this Perspective, we report an overview of the emerging role of TSPO at the heart level, focusing on the recent literature concerning the development of TSPO ligands used for fighting and imaging heart-related disease conditions. Accordingly, targeting TSPO might represent a successful strategy to achieve novel therapeutic and diagnostic strategies to unravel the fundamental mechanisms and to provide solutions to still unanswered questions in CDs.
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Affiliation(s)
- Emma Baglini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Valeria Poggetti
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Chiara Cavallini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Debora Petroni
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Francesca Forini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Giuseppina Nicolini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Elisabetta Barresi
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Silvia Salerno
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Barbara Costa
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Patricia Iozzo
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Danilo Neglia
- Fondazione
CNR/Regione Toscana Gabriele Monasterio, Cardiovascular and Imaging
Departments, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Luca Menichetti
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Sabrina Taliani
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Federico Da Settimo
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
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2
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Hosler J, Hoang N, Edwards KS. The cyclic lipopeptide micafungin induces rupture of isolated mitochondria by reprograming the mitochondrial inner membrane anion channel. Mitochondrion 2023; 71:50-62. [PMID: 37201620 PMCID: PMC10524837 DOI: 10.1016/j.mito.2023.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 04/17/2023] [Accepted: 05/07/2023] [Indexed: 05/20/2023]
Abstract
The antifungal activity of the drug micafungin, a cyclic lipopeptide that interacts with membrane proteins, may involve inhibition of fungal mitochondria. In humans, mitochondria are spared by the inability of micafungin to cross the cytoplasmic membrane. Using isolated mitochondria, we find that micafungin initiates the uptake of salts, causing rapid swelling and rupture of mitochondria with release of cytochrome c. The inner membrane anion channel (IMAC) is altered by micafungin to transfer both cations and anions. We propose that binding of anionic micafungin to IMAC attracts cations into the ion pore for the rapid transfer of ion pairs.
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Affiliation(s)
- Jonathan Hosler
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 N. State St., Jackson, MS 39216, United States
| | - Ngoc Hoang
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 N. State St., Jackson, MS 39216, United States
| | - Kristin Shirey Edwards
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 N. State St., Jackson, MS 39216, United States.
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3
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Angelovski M, Hadzi-Petrushev N, Mitrokhin V, Kamkin A, Mladenov M. Myocardial infarction and oxidative damage in animal models: objective and expectations from the application of cysteine derivatives. Toxicol Mech Methods 2023; 33:1-17. [PMID: 35450505 DOI: 10.1080/15376516.2022.2069530] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Reactive oxygen species (ROS) and associated oxidative stress are the main contributors to pathophysiological changes following myocardial infarction (MI), which is the principal cause of death from cardiovascular disease. The glutathione (GSH)/glutathione peroxidase (GPx) system appears to be the main and most active cardiac antioxidant mechanism. Hence, enhancement of the myocardial GSH system might have protective effects in the setting of MI. It follows that by increasing antioxidant capacity, the heart will be able to reduce the damage associated with MI and even prevent/weaken the occurrence of oxidative stress, which is highly ranked among the factors responsible for the occurrence of acute MI. For these reasons, the primary goal of future investigations should be to address the effects of different antioxidative compounds and especially cysteine derivatives like N-acetyl cysteine (NAC) and L-2-oxothiazolidine-4-carboxylic acid (OTC) as precursors responsible for the enhancement of the GSH-related antioxidant system's capacity. It is assumed that this will lay down the basis for elucidation of the mechanisms throughout which applicable doses of OTC will manifest a potentially positive impact in the reduction of adverse effects of acute MI. The inclusion of OTC in the models for prediction of the distribution of oxygen in infarcted animal hearts can help to upgrade existing computational models. Such a model would be based on computational geometries of the heart, but the inclusion of biochemical redox features in addition to angiogenic therapy, despite improvement of the post-infarcted oxygenated outcome could enhance the accuracy of the predictive values of oxygenation.
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Affiliation(s)
- Marija Angelovski
- Institute of Biology, Faculty of Natural Science and Mathematics, Ss Cyril and Methodius University, Skopje, North Macedonia
| | - Nikola Hadzi-Petrushev
- Institute of Biology, Faculty of Natural Science and Mathematics, Ss Cyril and Methodius University, Skopje, North Macedonia
| | - Vadim Mitrokhin
- Department of Fundamental and Applied Physiology, Russian National Research Medical University, Moscow, Russia
| | - Andre Kamkin
- Department of Fundamental and Applied Physiology, Russian National Research Medical University, Moscow, Russia
| | - Mitko Mladenov
- Institute of Biology, Faculty of Natural Science and Mathematics, Ss Cyril and Methodius University, Skopje, North Macedonia.,Department of Fundamental and Applied Physiology, Russian National Research Medical University, Moscow, Russia
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4
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Elezaby A, Dexheimer R, Sallam K. Cardiovascular effects of immunosuppression agents. Front Cardiovasc Med 2022; 9:981838. [PMID: 36211586 PMCID: PMC9534182 DOI: 10.3389/fcvm.2022.981838] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/30/2022] [Indexed: 11/26/2022] Open
Abstract
Immunosuppressive medications are widely used to treat patients with neoplasms, autoimmune conditions and solid organ transplants. Key drug classes, namely calcineurin inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and purine synthesis inhibitors, have direct effects on the structure and function of the heart and vascular system. In the heart, immunosuppressive agents modulate cardiac hypertrophy, mitochondrial function, and arrhythmia risk, while in vasculature, they influence vessel remodeling, circulating lipids, and blood pressure. The aim of this review is to present the preclinical and clinical literature examining the cardiovascular effects of immunosuppressive agents, with a specific focus on cyclosporine, tacrolimus, sirolimus, everolimus, mycophenolate, and azathioprine.
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Affiliation(s)
- Aly Elezaby
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Ryan Dexheimer
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
| | - Karim Sallam
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
- *Correspondence: Karim Sallam
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5
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Liu C, Ma N, Guo Z, Zhang Y, Zhang J, Yang F, Su X, Zhang G, Xiong X, Xing Y. Relevance of mitochondrial oxidative stress to arrhythmias: Innovative concepts to target treatments. Pharmacol Res 2021; 175:106027. [PMID: 34890774 DOI: 10.1016/j.phrs.2021.106027] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 11/26/2021] [Accepted: 12/05/2021] [Indexed: 12/13/2022]
Abstract
Cardiac arrhythmia occurs frequently worldwide, and in severe cases can be fatal. Mitochondria are the power plants of cardiomyocytes. In recent studies, mitochondria under certain stimuli produced excessive reactive oxygen species (ROS), which affect the normal function of cardiomyocytes through ion channels and related proteins. Mitochondrial oxidative stress (MOS) plays a key role in diseases with multifactorial etiopathogenesis, such as arrhythmia; MOS can lead to arrhythmias such as atrial fibrillation and ventricular tachycardia. This review discusses the mechanisms of arrhythmias caused by MOS, particularly of ROS produced by mitochondria. MOS can cause arrhythmias by affecting the activities of Ca2+-related proteins, the mitochondrial permeability transition pore protein, connexin 43, hyperpolarization-activated cyclic nucleotide-gated potassium channel 4, and ion channels. Based on these mechanisms, we discuss possible new treatments for arrhythmia. Targeted treatments focusing on mitochondria may reduce the progression of arrhythmias, as well as the occurrence of severe arrhythmias, and may be effective for personalized disease prevention.
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Affiliation(s)
- Can Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Ning Ma
- Dezhou Second People's Hospital, Dezhou 253000, China
| | - Ziru Guo
- Xingtai People's Hospital, Xingtai 054001, China
| | - Yijun Zhang
- The First Affiliated Hospital, Hebei North University, Zhangjiakou 075000, China
| | - Jianzhen Zhang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China
| | - Fan Yang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xin Su
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Guoxia Zhang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xingjiang Xiong
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
| | - Yanwei Xing
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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6
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Bland AR, Payne FM, Ashton JC, Jamialahmadi T, Sahebkar A. The cardioprotective actions of statins in targeting mitochondrial dysfunction associated with myocardial ischaemia-reperfusion injury. Pharmacol Res 2021; 175:105986. [PMID: 34800627 DOI: 10.1016/j.phrs.2021.105986] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 12/24/2022]
Abstract
During cardiac reperfusion after myocardial infarction, the heart is subjected to cascading cycles of ischaemia reperfusion injury (IRI). Patients presenting with this injury succumb to myocardial dysfunction resulting in myocardial cell death, which contributes to morbidity and mortality. New targeted therapies are required if the myocardium is to be protected from this injury and improve patient outcomes. Extensive research into the role of mitochondria during ischaemia and reperfusion has unveiled one of the most important sites contributing towards this injury; specifically, the opening of the mitochondrial permeability transition pore. The opening of this pore occurs during reperfusion and results in mitochondria swelling and dysfunction, promoting apoptotic cell death. Activation of mitochondrial ATP-sensitive potassium channels (mitoKATP) channels, uncoupling proteins, and inhibition of glycogen synthase kinase-3β (GSK3β) phosphorylation have been identified to delay mitochondrial permeability transition pore opening and reduce reactive oxygen species formation, thereby decreasing infarct size. Statins have recently been identified to provide a direct cardioprotective effect on these specific mitochondrial components, all of which reduce the severity of myocardial IRI, promoting the ability of statins to be a considerate preconditioning agent. This review will outline what has currently been shown in regard to statins cardioprotective effects on mitochondria during myocardial IRI.
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Affiliation(s)
- Abigail R Bland
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - Fergus M Payne
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - John C Ashton
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - Tannaz Jamialahmadi
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashad, Iran; School of Medicine, The University of Western Australia, Perth, Australia; School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
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7
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Zhao T, Wu W, Sui L, Huang Q, Nan Y, Liu J, Ai K. Reactive oxygen species-based nanomaterials for the treatment of myocardial ischemia reperfusion injuries. Bioact Mater 2021; 7:47-72. [PMID: 34466716 PMCID: PMC8377441 DOI: 10.1016/j.bioactmat.2021.06.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/09/2021] [Accepted: 06/02/2021] [Indexed: 02/06/2023] Open
Abstract
Interventional coronary reperfusion strategies are widely adopted to treat acute myocardial infarction, but morbidity and mortality of acute myocardial infarction are still high. Reperfusion injuries are inevitable due to the generation of reactive oxygen species (ROS) and apoptosis of cardiac muscle cells. However, many antioxidant and anti-inflammatory drugs are largely limited by pharmacokinetics and route of administration, such as short half-life, low stability, low bioavailability, and side effects for treatment myocardial ischemia reperfusion injury. Therefore, it is necessary to develop effective drugs and technologies to address this issue. Fortunately, nanotherapies have demonstrated great opportunities for treating myocardial ischemia reperfusion injury. Compared with traditional drugs, nanodrugs can effectively increase the therapeutic effect and reduces side effects by improving pharmacokinetic and pharmacodynamic properties due to nanodrugs’ size, shape, and material characteristics. In this review, the biology of ROS and molecular mechanisms of myocardial ischemia reperfusion injury are discussed. Furthermore, we summarized the applications of ROS-based nanoparticles, highlighting the latest achievements of nanotechnology researches for the treatment of myocardial ischemia reperfusion injury. Cardiovascular diseases are the leading cause of death worldwide. Researches of the myocardial infarction pathology and development of new treatments have very important scientific significance in the biomedical field. Many nanomaterials have shown amazing therapeutic effects to reduce myocardial damage by eliminating ROS. Nanomaterials effectively reduced myocardial damage through eliminating ROS from NOXs, M-ETC, M-Ca2+, M-mPTP, and RIRR.
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Affiliation(s)
- Tianjiao Zhao
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410087, China.,Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410008, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410087, China
| | - Wei Wu
- Department of Geriatric Surgery, Xiangya Hospital, Central South University, Changsha, 410087, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410087, China
| | - Lihua Sui
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410008, China.,Hunan Provincial Key Laboratory of Cardiovascular Research, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410008, China
| | - Qiong Huang
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410087, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410087, China
| | - Yayun Nan
- Geriatric Medical Center, Ningxia People's Hospital, Yinchuan, 750003, China
| | - Jianhua Liu
- Department of Radiology, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Kelong Ai
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410008, China.,Hunan Provincial Key Laboratory of Cardiovascular Research, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410008, China
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8
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Ngo ATP, Parra-Izquierdo I, Aslan JE, McCarty OJT. Rho GTPase regulation of reactive oxygen species generation and signalling in platelet function and disease. Small GTPases 2021; 12:440-457. [PMID: 33459160 DOI: 10.1080/21541248.2021.1878001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Platelets are master regulators and effectors of haemostasis with increasingly recognized functions as mediators of inflammation and immune responses. The Rho family of GTPase members Rac1, Cdc42 and RhoA are known to be major components of the intracellular signalling network critical to platelet shape change and morphological dynamics, thus playing a major role in platelet spreading, secretion and thrombus formation. Initially linked to the regulation of actomyosin contraction and lamellipodia formation, recent reports have uncovered non-canonical functions of platelet RhoGTPases in the regulation of reactive oxygen species (ROS), where intrinsically generated ROS modulate platelet function and contribute to thrombus formation. Platelet RhoGTPases orchestrate oxidative processes and cytoskeletal rearrangement in an interconnected manner to regulate intracellular signalling networks underlying platelet activity and thrombus formation. Herein we review our current knowledge of the regulation of platelet ROS generation by RhoGTPases and their relationship with platelet cytoskeletal reorganization, activation and function.
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Affiliation(s)
- Anh T P Ngo
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA
| | - Ivan Parra-Izquierdo
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA.,Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Joseph E Aslan
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA.,Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, USA.,Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon, USA
| | - Owen J T McCarty
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA
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9
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Ransy C, Vaz C, Lombès A, Bouillaud F. Use of H 2O 2 to Cause Oxidative Stress, the Catalase Issue. Int J Mol Sci 2020; 21:E9149. [PMID: 33266350 PMCID: PMC7731207 DOI: 10.3390/ijms21239149] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 01/08/2023] Open
Abstract
Addition of hydrogen peroxide (H2O2) is a method commonly used to trigger cellular oxidative stress. However, the doses used (often hundreds of micromolar) are disproportionally high with regard to physiological oxygen concentration (low micromolar). In this study using polarographic measurement of oxygen concentration in cellular suspensions we show that H2O2 addition results in O2 release as expected from catalase reaction. This reaction is fast enough to, within seconds, decrease drastically H2O2 concentration and to annihilate it within a few minutes. Firstly, this is likely to explain why recording of oxidative damage requires the high concentrations found in the literature. Secondly, it illustrates the potency of intracellular antioxidant (H2O2) defense. Thirdly, it complicates the interpretation of experiments as subsequent observations might result from high/transient H2O2 exposure and/or from the diverse possible consequences of the O2 release.
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Affiliation(s)
| | | | | | - Frédéric Bouillaud
- Institut Cochin, Université de Paris, INSERM, CNRS, F-75014 Paris, France; (C.R.); (C.V.); (A.L.)
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10
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Nitrogen Dioxide Inhalation Exposures Induce Cardiac Mitochondrial Reactive Oxygen Species Production, Impair Mitochondrial Function and Promote Coronary Endothelial Dysfunction. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17155526. [PMID: 32751709 PMCID: PMC7432061 DOI: 10.3390/ijerph17155526] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 01/01/2023]
Abstract
Traffic air pollution is a major health problem and is recognized as an important risk factor for cardiovascular (CV) diseases. In a previous experimental study, we showed that diesel exhaust (DE) exposures induced cardiac mitochondrial and CV dysfunctions associated with the gaseous phase. Here, we hypothesized that NO2 exposures to levels close to those found in DE induce a mitochondrial reactive oxygen species (ROS) production, which contribute to an endothelial dysfunction, an early indicator for numerous CV diseases. For this, we studied the effects of NO2 on ROS production and its impacts on the mitochondrial, coronary endothelial and cardiac functions, after acute (one single exposure) and repeated (three h/day, five days/week for three weeks) exposures in Wistar rats. Acute NO2 exposure induced an early but reversible mitochondrial ROS production. This event was isolated since neither mitochondrial function nor endothelial function were impaired, whereas cardiac function assessment showed a reversible left ventricular dysfunction. Conversely, after three weeks of exposure this alteration was accompanied by a cardiac mitochondrial dysfunction highlighted by an alteration of adenosine triphosphate (ATP) synthesis and oxidative phosphorylation and an increase in mitochondrial ROS production. Moreover, repeated NO2 exposures promoted endothelial dysfunction of the coronary arteries, as shown by reduced acetylcholine-induced vasodilatation, which was due, at least partially, to a superoxide-dependent decrease of nitric oxide (NO) bioavailability. This study shows that NO2 exposures impair cardiac mitochondrial function, which, in conjunction with coronary endothelial dysfunction, contributes to cardiac dysfunction. Together, these results clearly identify NO2 as a probable risk factor in ischemic heart diseases.
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11
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Adameova A, Shah AK, Dhalla NS. Role of Oxidative Stress in the Genesis of Ventricular Arrhythmias. Int J Mol Sci 2020; 21:ijms21124200. [PMID: 32545595 PMCID: PMC7349053 DOI: 10.3390/ijms21124200] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/05/2020] [Accepted: 06/10/2020] [Indexed: 12/11/2022] Open
Abstract
Ventricular arrhythmias, mainly lethal arrhythmias, such as ventricular tachycardia and fibrillation, may lead to sudden cardiac death. These are triggered as a result of cardiac injury due to chronic ischemia, acute myocardial infarction and various stressful conditions associated with increased levels of circulating catecholamines and angiotensin II. Several mechanisms have been proposed to underlie electrical instability of the heart promoting ventricular arrhythmias; however, oxidative stress which adversely affects ion homeostasis due to changes in the ion channel structure and function, seems to play a critical role in eliciting different types of ventricular arrhythmias. Prevention or mitigation of the severity of ventricular arrhythmias due to antioxidants has been indicated as the fundamental contribution in the field of preventive cardiology; however, novel interventions have to be developed for greater effectiveness and specificity in attenuating the adverse effects of oxidative stress. In this review, we have attempted to discuss proarrhythmic effects of oxidative stress differing in time and concentration dependence and highlight a molecular and cellular concept how it alters cardiac cell automaticity and conduction velocity sensitizing the probability of ventricular arrhythmias with resultant sudden cardiac death due to ischemic heart disease and other stressful situations. It is concluded that pharmacological approaches targeting multiple mechanisms besides oxidative stress might be more effective in the treatment of ventricular arrhythmias than current antiarrhythmic therapy.
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Affiliation(s)
- Adriana Adameova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, and Center of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, Odbojarov 10, 83232 Bratislava, Slovakia
- Correspondence:
| | - Anureet K. Shah
- Department of Kinesiology, Nutrition and Food Science, California State University, Los Angeles, CA 90032, USA;
| | - Naranjan S. Dhalla
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, and Department of Physiology & Pathophysiology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0W2, Canada;
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12
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Singh J, Barrett J, Sangaletti R, Dietrich WD, Rajguru SM. Additive Protective Effects of Delayed Mild Therapeutic Hypothermia and Antioxidants on PC12 Cells Exposed to Oxidative Stress. Ther Hypothermia Temp Manag 2020; 11:77-87. [PMID: 32302519 DOI: 10.1089/ther.2019.0034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mild therapeutic hypothermia is protective against several cellular stresses, but the mechanisms underlying this protection are not completely resolved. In the present study, we used an in vitro model to investigate whether therapeutic hypothermia at 33°C applied following a peroxide-induced oxidative stress would protect PC12 cells. A 1-hour exposure to tert-butyl peroxide increased cell death measured 24 hours later. This cell death was dose-dependent in the range of 100-1000 μM tert-butyl peroxide with ∼50% cell death observed at 24 hours from 500 μM peroxide exposure. Cell survival/death was measured with an alamarBlue viability assay, and propidium iodide/Hoechst imaging for counts of living and dead cells. Therapeutic hypothermia at 33°C applied for 2 hours postperoxide exposure significantly increased cell survival measured 24 hours postperoxide-induced stress. This protection was present even when delayed hypothermia, 15 minutes after the peroxide washout, was applied. Addition of any of the three FDA-approved antioxidants (Tempol, EUK134, Edaravone at 100 μM) in combination with hypothermia improved cell survival. With the therapeutic hypothermia treatment, a significant downregulation of caspases-3 and -8 and tumor necrosis factor-α was observed at 3 and 24 hours poststress. Consistent with this, a cell-permeable pan-caspase inhibitor Z-VAD-FMK applied in combination with hypothermia significantly increased cell survival. Overall, these results suggest that the antioxidants quenching of reactive oxygen species likely works with hypothermia to reduce mitochondrial damage and/or apoptotic mechanisms. Further studies are required to confirm and extend these results to other cell types, including neuronal cells, and other forms of oxidative stress as well as to optimize the critical parameters of hypothermia treatment such as target temperature and duration.
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Affiliation(s)
- Jayanti Singh
- Department of Otolaryngology, University of Miami, Miami, Florida, USA
| | - John Barrett
- Department of Physiology and Biophysics, University of Miami, Miami, Florida, USA
| | | | - W Dalton Dietrich
- Department of Biomedical Engineering, University of Miami, Miami, Florida, USA.,Department of Neurological Surgery, University of Miami, Miami, Florida, USA
| | - Suhrud M Rajguru
- Department of Otolaryngology, University of Miami, Miami, Florida, USA.,Department of Biomedical Engineering, University of Miami, Miami, Florida, USA
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13
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Zeng X, Huang Q, Long SL, Zhong Q, Mo Z. Mitochondrial Dysfunction in Polycystic Ovary Syndrome. DNA Cell Biol 2020; 39:1401-1409. [PMID: 32077751 DOI: 10.1089/dna.2019.5172] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Polycystic ovary syndrome (PCOS) is one of the most common female reproductive metabolisms. It is an endocrine disease that affects reproductive women and often exhibits with hyperandrogenemia, insulin resistance (IR), low inflammation, and an increased risk of type 2 diabetes mellitus, metabolic syndrome, and cardiovascular events such as hypertension and dyslipidemia in patients. However, the molecular mechanism of PCOS is still unclear. Recently, an increasing number of studies have shown that the oxidative stress induced by mitochondrial dysfunction has negative effects on IR, lipid metabolism, and follicular development, suggesting that mitochondrial dysfunction plays an essential role in the development of PCOS. Abnormal mitochondrial DNA copy number in patients with PCOS, and mitochondrial gene mutations, has been the focus of research in recent years, and functional mitochondrial diseases have been gradually accepted as a related factor in PCOS. This review is intended to summarize and discuss previous and recent studies and findings on the connections between mitochondrial dysfunction and PCOS.
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Affiliation(s)
- Xin Zeng
- Department of Histology and Embryology, Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Qin Huang
- Department of Histology and Embryology, Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Shuang Lian Long
- Department of Histology and Embryology, Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Qiaoqing Zhong
- Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Zhongcheng Mo
- Department of Histology and Embryology, Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical School, University of South China, Hengyang, Hunan, China.,Institute of Basic Medical Sciences, Guilin Medical University, Guangxi, Guilin, China
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14
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Guo Y, You Y, Lv D, Yan J, Shang FF, Wang X, Zhang C, Fan Q, Luo S. Inducible nitric oxide synthase contributes to insulin resistance and cardiac dysfunction after burn injury in mice. Life Sci 2019; 239:116912. [PMID: 31634465 DOI: 10.1016/j.lfs.2019.116912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/12/2019] [Accepted: 09/24/2019] [Indexed: 11/18/2022]
Abstract
AIMS Cardiac dysfunction is a major cause of multi-organ dysfunction in critical care units following severe burns. The purpose of this study was to investigate the role of inducible nitric oxide synthase (iNOS) in cardiac dysfunction in burned mice. MATERIALS AND METHODS Wild-type and iNOS-knockout mice were subjected to 30% total body surface area burns. Next, the expression of iNOS was measured at 1, 3 and 7 days post-burn. Cardiac function, insulin sensitivity, inflammation, oxidative stress, and apoptosis in the hearts of the mice were assessed at 3 days post-burn. KEY FINDINGS Compared to control mice, iNOS expression was increased and reached a maximum in the heart of burned mice at 3 days post-burn. iNOS deficiency significantly alleviated the cardiac dysfunction and insulin resistance in burned mice. In addition, burn-induced inflammation, oxidative stress, and apoptosis in the heart were markedly reduced in iNOS-knockout burned mice when compared to corresponding values in wild-type burned mice. SIGNIFICANCE Our study demonstrates that iNOS contributes to insulin resistance in the hearts of mice following burn injury, and iNOS deficiency protects cardiac function against burn injury in mice, suggesting iNOS as a potential therapeutic target to treat burn injuries.
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Affiliation(s)
- Yongzheng Guo
- Division of cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China; Institute of Life Science, Chongqing Medical University, Chongqing, 400016, China
| | - Yuehua You
- Division of cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China; Institute of Life Science, Chongqing Medical University, Chongqing, 400016, China
| | - Dingyi Lv
- Division of cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China; Institute of Life Science, Chongqing Medical University, Chongqing, 400016, China
| | - Jianghong Yan
- Institute of Life Science, Chongqing Medical University, Chongqing, 400016, China
| | - Fei-Fei Shang
- Institute of Life Science, Chongqing Medical University, Chongqing, 400016, China
| | - Xiaowen Wang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Cheng Zhang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Qingdan Fan
- Division of cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Suxin Luo
- Division of cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
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15
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van der Weg K, Prinzen FW, Gorgels AP. Editor's Choice- Reperfusion cardiac arrhythmias and their relation to reperfusion-induced cell death. EUROPEAN HEART JOURNAL-ACUTE CARDIOVASCULAR CARE 2018; 8:142-152. [PMID: 30421619 DOI: 10.1177/2048872618812148] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Reperfusion does not only salvage ischaemic myocardium but can also cause additional cell death which is called lethal reperfusion injury. The time of reperfusion is often accompanied by ventricular arrhythmias, i.e. reperfusion arrhythmias. While both conditions are seen as separate processes, recent research has shown that reperfusion arrhythmias are related to larger infarct size. The pathophysiology of fatal reperfusion injury revolves around intracellular calcium overload and reactive oxidative species inducing apoptosis by opening of the mitochondrial protein transition pore. The pathophysiological basis for reperfusion arrhythmias is the same intracellular calcium overload as that causing fatal reperfusion injury. Therefore both conditions should not be seen as separate entities but as one and the same process resulting in two different visible effects. Reperfusion arrhythmias could therefore be seen as a potential marker for fatal reperfusion injury.
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Affiliation(s)
- Kirian van der Weg
- 1 Department of Cardiology, Maastricht University Medical Center, The Netherlands
| | - Frits W Prinzen
- 2 Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, The Netherlands
| | - Anton Pm Gorgels
- 1 Department of Cardiology, Maastricht University Medical Center, The Netherlands.,2 Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, The Netherlands
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16
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Ilkan Z, Akar FG. The Mitochondrial Translocator Protein and the Emerging Link Between Oxidative Stress and Arrhythmias in the Diabetic Heart. Front Physiol 2018; 9:1518. [PMID: 30416455 PMCID: PMC6212558 DOI: 10.3389/fphys.2018.01518] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/09/2018] [Indexed: 02/06/2023] Open
Abstract
The mitochondrial translocator protein (TSPO) is a key outer mitochondrial membrane protein that regulates the activity of energy-dissipating mitochondrial channels in response to oxidative stress. In this article, we provide an overview of the role of TSPO in the systematic amplification of reactive oxygen species (ROS) through an autocatalytic process known as ROS-induced ROS-release (RIRR). We describe how this TSPO-driven process destabilizes the mitochondrial membrane potential leading to electrical instability at the cellular and whole heart levels. Finally, we provide our perspective on the role of TSPO in the pathophysiology of diabetes, in general and diabetes-related arrhythmias, in particular.
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Affiliation(s)
- Zeki Ilkan
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Fadi G Akar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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17
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Costiniti V, Spera I, Menabò R, Palmieri EM, Menga A, Scarcia P, Porcelli V, Gissi R, Castegna A, Canton M. Monoamine oxidase-dependent histamine catabolism accounts for post-ischemic cardiac redox imbalance and injury. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3050-3059. [DOI: 10.1016/j.bbadis.2018.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/25/2018] [Accepted: 06/20/2018] [Indexed: 12/11/2022]
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18
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Holland NA, Fraiser CR, Sloan RC, Devlin RB, Brown DA, Wingard CJ. Ultrafine Particulate Matter Increases Cardiac Ischemia/Reperfusion Injury via Mitochondrial Permeability Transition Pore. Cardiovasc Toxicol 2018; 17:441-450. [PMID: 28194639 DOI: 10.1007/s12012-017-9402-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ultrafine particulate matter (UFP) has been associated with increased cardiovascular morbidity and mortality. However, the mechanisms that drive PM-associated cardiovascular disease and dysfunction remain unclear. We examined the impact of oropharyngeal aspiration of 100 μg UFP from the Chapel Hill, NC, air shed in Sprague-Dawley rats on cardiac function, arrhythmogenesis, and cardiac ischemia/reperfusion (I/R) injury using a Langendorff working heart model. We found that exposure to UFP was capable of significantly exacerbating cardiac I/R injury without changing overall cardiac function or major changes in arrhythmogenesis. Cardiac I/R injury was attenuable with administration of cyclosporin A (CsA), suggesting a role for the mitochondrial permeability transition pore (mPTP) in UFP-associated cardiovascular toxicity. Isolated cardiac mitochondria displayed decreased Ca2+ buffering before opening of the mPTP. These findings suggest that UFP-induced expansion of cardiac I/R injury may be a result of mPTP Ca2+ sensitization resulting in increased mitochondrial permeability transition and potential initiation of mPTP-associated cell death pathways.
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Affiliation(s)
- Nathan A Holland
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Chad R Fraiser
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Ruben C Sloan
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Robert B Devlin
- National Health and Environmental Effects Research Laboratory, Environmental Public Health Division, US Environmental Protection Agency, Chapel Hill, NC, USA
| | - David A Brown
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Christopher J Wingard
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA. .,Lansing School of Nursing and Health Sciences, Physical Therapy Department, Bellarmine University, 2001 Newburg Rd, Louisville, KY, 40205, USA.
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19
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Gambardella J, Sorriento D, Ciccarelli M, Del Giudice C, Fiordelisi A, Napolitano L, Trimarco B, Iaccarino G, Santulli G. Functional Role of Mitochondria in Arrhythmogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:191-202. [PMID: 28551788 DOI: 10.1007/978-3-319-55330-6_10] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Growing evidence indicate that mitochondria play a functional role in arrhythmogenesis. We report here the molecular mechanisms underlying the action of these highly dynamic organelles in the regulation of cell metabolism, action potential and, overall, heart excitability. In particular, we examine the role of cardiac mitochondria in linking metabolism and cell excitability. The importance of the main mitochondrial channels is evaluated as well, including the recently identified calcium uniporter. Promises and pitfalls of potential therapeutic strategies targeting mitochondrial pathways are also assessed.
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Affiliation(s)
- Jessica Gambardella
- Columbia University Medical Center, New York, NY, USA.,Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Italy
| | - Daniela Sorriento
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Michele Ciccarelli
- Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Italy
| | - Carmine Del Giudice
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Antonella Fiordelisi
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Luigi Napolitano
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Bruno Trimarco
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Guido Iaccarino
- Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Italy
| | - Gaetano Santulli
- Dept. of Biomedical Advanced Sciences, Federico II University, Naples, Italy. .,Columbia University Medical Center, New York Presbyterian Hospital-Manhattan, New York, NY, USA.
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20
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Joseph LC, Kokkinaki D, Valenti MC, Kim GJ, Barca E, Tomar D, Hoffman NE, Subramanyam P, Colecraft HM, Hirano M, Ratner AJ, Madesh M, Drosatos K, Morrow JP. Inhibition of NADPH oxidase 2 (NOX2) prevents sepsis-induced cardiomyopathy by improving calcium handling and mitochondrial function. JCI Insight 2017; 2:94248. [PMID: 28878116 PMCID: PMC5621873 DOI: 10.1172/jci.insight.94248] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/25/2017] [Indexed: 01/12/2023] Open
Abstract
Cardiomyopathy frequently complicates sepsis and is associated with increased mortality. Increased cardiac oxidative stress and mitochondrial dysfunction have been observed during sepsis, but the mechanisms responsible for these abnormalities have not been determined. We hypothesized that NADPH oxidase 2 (NOX2) activation could be responsible for sepsis-induced oxidative stress and cardiomyopathy. Treatment of isolated adult mouse cardiomyocytes with low concentrations of the endotoxin lipopolysaccharide (LPS) increased total cellular reactive oxygen species (ROS) and mitochondrial superoxide. Elevated mitochondrial superoxide was accompanied by depolarization of the mitochondrial inner membrane potential, an indication of mitochondrial dysfunction, and mitochondrial calcium overload. NOX2 inhibition decreased LPS-induced superoxide and prevented mitochondrial dysfunction. Further, cardiomyocytes from mice with genetic ablation of NOX2 did not have LPS-induced superoxide or mitochondrial dysfunction. LPS decreased contractility and calcium transient amplitude in isolated cardiomyocytes, and these abnormalities were prevented by inhibition of NOX2. LPS decreased systolic function in mice, measured by echocardiography. NOX2 inhibition was cardioprotective in 2 mouse models of sepsis, preserving systolic function after LPS injection or cecal ligation and puncture (CLP). These data show that inhibition of NOX2 decreases oxidative stress, preserves intracellular calcium handling and mitochondrial function, and alleviates sepsis-induced systolic dysfunction in vivo. Thus, NOX2 is a potential target for pharmacotherapy of sepsis-induced cardiomyopathy.
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Affiliation(s)
- Leroy C. Joseph
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Dimitra Kokkinaki
- Metabolic Biology Laboratory, Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
- The Molecular Basis of Human Diseases Graduate Program, Faculty of Medicine, University of Crete, Voutes, 71003 Heraklion-Crete, Greece
| | - Mesele-Christina Valenti
- Metabolic Biology Laboratory, Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Grace J. Kim
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Emanuele Barca
- Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Dhanendra Tomar
- Department of Medical Genetics and Molecular Biochemistry, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Nicholas E. Hoffman
- Department of Medical Genetics and Molecular Biochemistry, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Prakash Subramanyam
- Department of Physiology and Cellular Biophysics, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Henry M. Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Michio Hirano
- Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Adam J. Ratner
- Departments of Pediatrics and Microbiology, New York University School of Medicine, New York, New York, USA
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Konstantinos Drosatos
- Metabolic Biology Laboratory, Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - John P. Morrow
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA
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21
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Andrienko TN, Pasdois P, Pereira GC, Ovens MJ, Halestrap AP. The role of succinate and ROS in reperfusion injury - A critical appraisal. J Mol Cell Cardiol 2017; 110:1-14. [PMID: 28689004 PMCID: PMC5678286 DOI: 10.1016/j.yjmcc.2017.06.016] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/14/2017] [Accepted: 06/30/2017] [Indexed: 12/20/2022]
Abstract
We critically assess the proposal that succinate-fuelled reverse electron flow (REF) drives mitochondrial matrix superoxide production from Complex I early in reperfusion, thus acting as a key mediator of ischemia/reperfusion (IR) injury. Real-time surface fluorescence measurements of NAD(P)H and flavoprotein redox state suggest that conditions are unfavourable for REF during early reperfusion. Furthermore, rapid loss of succinate accumulated during ischemia can be explained by its efflux rather than oxidation. Moreover, succinate accumulation during ischemia is not attenuated by ischemic preconditioning (IP) despite powerful cardioprotection. In addition, measurement of intracellular reactive oxygen species (ROS) during reperfusion using surface fluorescence and mitochondrial aconitase activity detected major increases in ROS only after mitochondrial permeability transition pore (mPTP) opening was first detected. We conclude that mPTP opening is probably triggered initially by factors other than ROS, including increased mitochondrial [Ca2+]. However, IP only attenuates [Ca2+] increases later in reperfusion, again after initial mPTP opening, implying that IP regulates mPTP opening through additional mechanisms. One such is mitochondria-bound hexokinase 2 (HK2) which dissociates from mitochondria during ischemia in control hearts but not those subject to IP. Indeed, there is a strong correlation between the extent of HK2 loss from mitochondria during ischemia and infarct size on subsequent reperfusion. Mechanisms linking HK2 dissociation to mPTP sensitisation remain to be fully established but several related processes have been implicated including VDAC1 oligomerisation, the stability of contact sites between the inner and outer membranes, cristae morphology, Bcl-2 family members and mitochondrial fission proteins such as Drp1.
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Affiliation(s)
- Tatyana N Andrienko
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Philippe Pasdois
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Gonçalo C Pereira
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Matthew J Ovens
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Andrew P Halestrap
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
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22
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Kuznetsov AV, Javadov S, Saks V, Margreiter R, Grimm M. Synchronism in mitochondrial ROS flashes, membrane depolarization and calcium sparks in human carcinoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:418-431. [PMID: 28279675 DOI: 10.1016/j.bbabio.2017.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/09/2017] [Accepted: 03/02/2017] [Indexed: 02/02/2023]
Abstract
Mitochondria are major producers of reactive oxygen species (ROS) in many cells including cancer cells. However, complex interrelationships between mitochondrial ROS (mitoROS), mitochondrial membrane potential (ΔΨm) and Ca2+ are not completely understood. Using human carcinoma cells, we further highlight biphasic ROS dynamics: - gradual mitoROS increase followed by mitoROS flash. Also, we demonstrate heterogeneity in rates of mitoROS generation and flash initiation time. Comparing mitochondrial and near-extra-mitochondrial signals, we show that mechanisms of mitoROS flashes in single mitochondria, linked to mitochondrial permeability transition pore opening (ΔΨm collapse) and calcium sparks, may involve flash triggering by certain levels of external ROS released from the same mitochondria. In addition, mitochondria-mitochondria interactions can produce wave propagations of mitoROS flashes and ΔΨm collapses in cancer cells similar to phenomena of ROS-induced ROS release (RIRR). Our data suggest that in cancer cells RIRR, activation of mitoROS flashes and mitochondrial depolarization may involve participation of extramitochondrial-ROS produced either by individual mitochondria and/or by neighboring mitochondria. This could represent general mechanisms in ROS-ROS signaling with suggested role in both mitochondrial and cellular physiology and signaling.
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Affiliation(s)
- Andrey V Kuznetsov
- Cardiac Surgery Laboratory, Department of Heart Surgery, Medical University of Innsbruck, Innsbruck A-6020, Austria.
| | - Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, USA
| | - Valdur Saks
- Laboratory of Fundamental and Applied Bioenergetics, INSERM U884, University Joseph Fourier, Grenoble, France
| | - Raimund Margreiter
- Department of Visceral, Transplant and Thoracic Surgery, Medical University of Innsbruck, Innsbruck, Austria
| | - Michael Grimm
- Cardiac Surgery Laboratory, Department of Heart Surgery, Medical University of Innsbruck, Innsbruck A-6020, Austria
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23
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Reducing mitochondrial bound hexokinase II mediates transition from non-injurious into injurious ischemia/reperfusion of the intact heart. J Physiol Biochem 2017; 73:323-333. [PMID: 28258543 PMCID: PMC5534207 DOI: 10.1007/s13105-017-0555-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 02/10/2017] [Indexed: 01/11/2023]
Abstract
Ischemia/reperfusion (I/R) of the heart becomes injurious when duration of the ischemic insult exceeds a certain threshold (approximately ≥20 min). Mitochondrial bound hexokinase II (mtHKII) protects against I/R injury, with the amount of mtHKII correlating with injury. Here, we examine whether mtHKII can induce the transition from non-injurious to injurious I/R, by detaching HKII from mitochondria during a non-injurious I/R interval. Additionally, we examine possible underlying mechanisms (increased reactive oxygen species (ROS), increased oxygen consumption (MVO2) and decreased cardiac energetics) associated with this transition. Langendorff perfused rat hearts were treated for 20 min with saline, TAT-only or 200 nM TAT-HKII, a peptide that translocates HKII from mitochondria. Then, hearts were exposed to non-injurious 15-min ischemia, followed by 30-min reperfusion. I/R injury was determined by necrosis (LDH release) and cardiac mechanical recovery. ROS were measured by DHE fluorescence. Changes in cardiac respiratory activity (cardiac MVO2 and efficiency and mitochondrial oxygen tension (mitoPO2) using protoporphyrin IX) and cardiac energetics (ATP, PCr, ∆GATP) were determined following peptide treatment. When exposed to 15-min ischemia, control hearts had no necrosis and 85% recovery of function. Conversely, TAT-HKII treatment resulted in significant LDH release and reduced cardiac recovery (25%), indicating injurious I/R. This was associated with increased ROS during ischemia and reperfusion. TAT-HKII treatment reduced MVO2 and improved energetics (increased PCr) before ischemia, without affecting MVO2/RPP ratio or mitoPO2. In conclusion, a reduction in mtHKII turns non-injurious I/R into injurious I/R. Loss of mtHKII was associated with increased ROS during ischemia and reperfusion, but not with increased MVO2 or decreased cardiac energetics before damage occurs.
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24
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Ishihara Y, Tsuji M, Kawamoto T, Yamazaki T. Involvement of reactive oxygen species derived from mitochondria in neuronal injury elicited by methylmercury. J Clin Biochem Nutr 2016; 59:182-190. [PMID: 27895385 PMCID: PMC5110935 DOI: 10.3164/jcbn.16-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/04/2016] [Indexed: 01/02/2023] Open
Abstract
Methylmercury induces oxidative stress and subsequent neuronal injury. However, the mechanism by which methylmercury elicits reactive oxygen species (ROS) production remains under debate. In this study, we investigated the involvement of mitochondrial ROS in methylmercury-induced neuronal cell injury using human neuroblastoma SH-SY5Y-derived ρ0 cells, which have a deletion of mitochondrial DNA and thus decreased respiratory activity. SH-SY5Y cells were cultured for 60 days in the presence of ethidium bromide to produce ρ0 cells. Our ρ0 cells showed decreases in the cytochrome c oxidase expression and activity as well as oxygen consumption compared with original SH-SY5Y cells. Methylmercury at a concentration of 1 µM induced cell death with oxidative stress in original SH-SY5Y cells, but not ρ0 cells, indicating that ρ0 cells are resistant to methylmercury-induced oxidative stress. ρ0 cells also showed tolerance against hydrogen peroxide and superoxide anion, suggesting that ρ0 cells are resistant to total ROS. These data indicate that mitochondrial ROS are clearly involved in oxidative stress and subsequent cell death induced by methylmercury. Considering that the dominant mechanism of ROS generation elicited by methylmercury is due to direct antioxidant enzyme inhibition, mitochondria might play a role in amplifying ROS in methylmercury-induced neurotoxicity.
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Affiliation(s)
- Yasuhiro Ishihara
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
| | - Mayumi Tsuji
- Department of Environmental Health, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata-nishi-ku, Kitakyushu, Fukuoka 807-8555, Japan
| | - Toshihiro Kawamoto
- Department of Environmental Health, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata-nishi-ku, Kitakyushu, Fukuoka 807-8555, Japan
| | - Takeshi Yamazaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Japan
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25
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Charvat RA, Arrizabalaga G. Oxidative stress generated during monensin treatment contributes to altered Toxoplasma gondii mitochondrial function. Sci Rep 2016; 6:22997. [PMID: 26976749 PMCID: PMC4792157 DOI: 10.1038/srep22997] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 02/26/2016] [Indexed: 02/08/2023] Open
Abstract
The ionophore monensin displays potent activities against several coccidian parasites of veterinary and medical importance including the opportunistic pathogen of humans, Toxoplasma gondii. While monensin is used widely in animals, toxicity impedes its use in humans. Nonetheless, given its potency, understanding its mode of action would reveal vulnerable aspects of the parasite that can be exploited for drug development. We previously established that monensin induces Toxoplasma to undergo cell cycle arrest and an autophagy-like cell death. Interestingly, these effects are dependent on the mitochondrion-localized TgMSH-1 protein, suggesting that monensin disrupts mitochondrial function. We demonstrate that monensin treatment results in decreased mitochondrial membrane potential and altered morphology. These effects are mitigated by the antioxidant compound N-acetyl-cysteine suggesting that monensin causes an oxidative stress, which was indeed the case based on direct detection of reactive oxygen species. Moreover, over-expression of the antioxidant proteins glutaredoxin and peroxiredoxin 2 protect Toxoplasma from the deleterious effects of monensin. Thus, our studies show that the effects of monensin on Toxoplasma are due to a disruption of mitochondrial function caused by the induction of an oxidative stress and implicate parasite redox biology as a viable target for the development of drugs against Toxoplasma and related pathogenic parasites.
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Affiliation(s)
- Robert A Charvat
- Departments of Pharmacology and Toxicology Indiana University School of Medicine, Indianapolis, Indiana 46202, US
| | - Gustavo Arrizabalaga
- Departments of Pharmacology and Toxicology Indiana University School of Medicine, Indianapolis, Indiana 46202, US.,Departments of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202, US
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Inhibition of NAPDH Oxidase 2 (NOX2) Prevents Oxidative Stress and Mitochondrial Abnormalities Caused by Saturated Fat in Cardiomyocytes. PLoS One 2016; 11:e0145750. [PMID: 26756466 PMCID: PMC4710525 DOI: 10.1371/journal.pone.0145750] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/08/2015] [Indexed: 12/29/2022] Open
Abstract
Obesity and high saturated fat intake increase the risk of heart failure and arrhythmias. The molecular mechanisms are poorly understood. We hypothesized that physiologic levels of saturated fat could increase mitochondrial reactive oxygen species (ROS) in cardiomyocytes, leading to abnormalities of calcium homeostasis and mitochondrial function. We investigated the effect of saturated fat on mitochondrial function and calcium homeostasis in isolated ventricular myocytes. The saturated fatty acid palmitate causes a decrease in mitochondrial respiration in cardiomyocytes. Palmitate, but not the monounsaturated fatty acid oleate, causes an increase in both total cellular ROS and mitochondrial ROS. Palmitate depolarizes the mitochondrial inner membrane and causes mitochondrial calcium overload by increasing sarcoplasmic reticulum calcium leak. Inhibitors of PKC or NOX2 prevent mitochondrial dysfunction and the increase in ROS, demonstrating that PKC-NOX2 activation is also required for amplification of palmitate induced-ROS. Cardiomyocytes from mice with genetic deletion of NOX2 do not have palmitate-induced ROS or mitochondrial dysfunction. We conclude that palmitate induces mitochondrial ROS that is amplified by NOX2, causing greater mitochondrial ROS generation and partial depolarization of the mitochondrial inner membrane. The abnormal sarcoplasmic reticulum calcium leak caused by palmitate could promote arrhythmia and heart failure. NOX2 inhibition is a potential therapy for heart disease caused by diabetes or obesity.
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Morin D, Musman J, Pons S, Berdeaux A, Ghaleh B. Mitochondrial translocator protein (TSPO): From physiology to cardioprotection. Biochem Pharmacol 2015; 105:1-13. [PMID: 26688086 DOI: 10.1016/j.bcp.2015.12.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/04/2015] [Indexed: 01/08/2023]
Abstract
The mitochondrial translocator protein (TSPO) is a high affinity cholesterol binding protein which is primarily located in the outer mitochondrial membrane where it has been shown to interact with proteins implicated in mitochondrial permeability transition pore (mPTP) formation. TSPO is found in different species and is expressed at high levels in tissues that synthesize steroids but is also present in other peripheral tissues especially in the heart. TSPO has been involved in the import of cholesterol into mitochondria, a key step in steroidogenesis. This constitutes the main established function of the protein which was recently challenged by genetic studies. TSPO has also been associated directly or indirectly with a wide range of cellular functions such as apoptosis, cell proliferation, differentiation, regulation of mitochondrial function or porphyrin transport. In the heart the role of TSPO remains undefined but a growing body of evidence suggests that TSPO plays a critical role in regulating physiological cardiac function and that TSPO ligands may represent interesting drugs to protect the heart under pathological conditions. This article briefly reviews current knowledge regarding TSPO and discusses its role in the cardiovascular system under physiological and pathologic conditions. More particularly, it provides evidence that TSPO can represent an alternative strategy to develop new pharmacological agents to protect the myocardium against ischemia-reperfusion injury.
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Affiliation(s)
- Didier Morin
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Julien Musman
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Sandrine Pons
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Alain Berdeaux
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Bijan Ghaleh
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
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Granger DN, Kvietys PR. Reperfusion injury and reactive oxygen species: The evolution of a concept. Redox Biol 2015; 6:524-551. [PMID: 26484802 PMCID: PMC4625011 DOI: 10.1016/j.redox.2015.08.020] [Citation(s) in RCA: 918] [Impact Index Per Article: 102.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 08/31/2015] [Indexed: 12/11/2022] Open
Abstract
Reperfusion injury, the paradoxical tissue response that is manifested by blood flow-deprived and oxygen-starved organs following the restoration of blood flow and tissue oxygenation, has been a focus of basic and clinical research for over 4-decades. While a variety of molecular mechanisms have been proposed to explain this phenomenon, excess production of reactive oxygen species (ROS) continues to receive much attention as a critical factor in the genesis of reperfusion injury. As a consequence, considerable effort has been devoted to identifying the dominant cellular and enzymatic sources of excess ROS production following ischemia-reperfusion (I/R). Of the potential ROS sources described to date, xanthine oxidase, NADPH oxidase (Nox), mitochondria, and uncoupled nitric oxide synthase have gained a status as the most likely contributors to reperfusion-induced oxidative stress and represent priority targets for therapeutic intervention against reperfusion-induced organ dysfunction and tissue damage. Although all four enzymatic sources are present in most tissues and are likely to play some role in reperfusion injury, priority and emphasis has been given to specific ROS sources that are enriched in certain tissues, such as xanthine oxidase in the gastrointestinal tract and mitochondria in the metabolically active heart and brain. The possibility that multiple ROS sources contribute to reperfusion injury in most tissues is supported by evidence demonstrating that redox-signaling enables ROS produced by one enzymatic source (e.g., Nox) to activate and enhance ROS production by a second source (e.g., mitochondria). This review provides a synopsis of the evidence implicating ROS in reperfusion injury, the clinical implications of this phenomenon, and summarizes current understanding of the four most frequently invoked enzymatic sources of ROS production in post-ischemic tissue. Reperfusion injury is implicated in a variety of human diseases and disorders. Evidence implicating ROS in reperfusion injury continues to grow. Several enzymes are candidate sources of ROS in post-ischemic tissue. Inter-enzymatic ROS-dependent signaling enhances the oxidative stress caused by I/R. .
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Affiliation(s)
- D Neil Granger
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, United States.
| | - Peter R Kvietys
- Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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Goh KY, Qu J, Hong H, Liu T, Dell'Italia LJ, Wu Y, O'Rourke B, Zhou L. Impaired mitochondrial network excitability in failing guinea-pig cardiomyocytes. Cardiovasc Res 2015; 109:79-89. [PMID: 26433944 DOI: 10.1093/cvr/cvv230] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 09/25/2015] [Indexed: 01/11/2023] Open
Abstract
AIMS Studies in guinea-pig cardiomyocytes show that reactive oxygen species (ROS) produced by a few mitochondria can propagate to their neighbours, triggering synchronized, cell-wide network oscillations via an ROS-induced ROS release (RIRR) mechanism. How mitochondria in cardiomyocytes from failing hearts (HF) respond to local oxidative stress perturbations has not been investigated. Since mitochondrial ultrastructure is reportedly disrupted in HF, and propagation of ROS signals depends on mitochondrial network integrity, we hypothesized that the laser flash-induced RIRR is altered in HF. METHODS AND RESULTS To test the hypothesis, pressure-overload HF was induced in guinea pigs by ascending aortic constriction leading to left ventricular dilatation and decreased ejection fraction after 8 weeks. Isolated cardiomyocytes were studied with two-photon/confocal microscopy to determine their basal oxidative stress and propensity to undergo mitochondrial depolarization/oscillations in response to local laser flash stimulations. The expression of mitofusin proteins and mitochondrial network structure were also analysed. Results showed that HF cardiomyocytes had higher baseline ROS levels and less reduced glutathione, and were more prone to laser flash-induced mitochondrial depolarization. In contrast, the delay between the laser flash and synchronized cell-wide network oscillations was prolonged in HF myocytes compared with shams, and the spatial extent of coupling was diminished, suggesting dampened RIRR and ROS signal propagation. In addition, the expressions of mitofusin proteins in HF myocardium were down-regulated compared with these from sham-operated animals, and the mitochondrial network structure altered. CONCLUSION The disrupted inter-mitochondrial tethering and loss of structural organization may underlie decreased ROS-dependent mitochondrial coupling in HF.
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Affiliation(s)
- Kah Yong Goh
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jing Qu
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Huixian Hong
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ting Liu
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Louis J Dell'Italia
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yong Wu
- Division of Molecular Medicine, Department of Anesthesiology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Lufang Zhou
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, AL, USA Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
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Liaudet L, Calderari B, Pacher P. Pathophysiological mechanisms of catecholamine and cocaine-mediated cardiotoxicity. Heart Fail Rev 2015; 19:815-24. [PMID: 24398587 DOI: 10.1007/s10741-014-9418-y] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Overactivation of the sympatho-adrenergic system is an essential mechanism providing short-term adaptation to the stressful conditions of critical illnesses. In the same way, the administration of exogenous catecholamines is mandatory to support the failing circulation in acutely ill patients. In contrast to these short-term benefits, prolonged adrenergic stress is detrimental to the cardiovascular system by initiating a series of adverse effects triggering significant cardiotoxicity, whose pathophysiological mechanisms are complex and only partially elucidated. In addition to the development of myocardial oxygen supply/demand imbalance induced by the sustained activation of adrenergic receptors, catecholamines can damage cardiomyocytes by fostering mitochondrial dysfunction, via two main mechanisms. The first one is calcium overload, consecutive to β-adrenergic receptor-mediated activation of protein kinase A and subsequent phosphorylation of multiple Ca(2+)-cycling proteins. The second one is oxidative stress, primarily related to the transformation of catecholamines into "aminochromes," which undergo redox cycling in mitochondria to generate copious amounts of oxygen-derived free radicals. In turn, calcium overload and oxidative stress promote mitochondrial permeability transition and cardiomyocyte cell death, both via the apoptotic and necrotic pathways. Comparable mechanisms of myocardial toxicity, including marked oxidative stress and mitochondrial dysfunction, have been reported with the use of cocaine, a common recreational drug with potent sympathomimetic activity. The aim of the current review is to present in detail the pathophysiological processes underlying the development of catecholamine and cocaine-induced cardiomyopathy, as such conditions may be frequently encountered in the clinical practice of cardiologists and ICU specialists.
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Affiliation(s)
- Lucas Liaudet
- Department of Intensive Care Medicine and Burn Center, Faculty of Biology and Medicine, University Hospital Medical Center, BH 08-621, 1010, Lausanne, Switzerland,
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The mitochondrial translocator protein and arrhythmogenesis in ischemic heart disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:234104. [PMID: 25918579 PMCID: PMC4397036 DOI: 10.1155/2015/234104] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/18/2015] [Indexed: 12/19/2022]
Abstract
Mitochondrial dysfunction is a hallmark of multiple cardiovascular disorders, including ischemic heart disease. Although mitochondria are well recognized for their role in energy production and cell death, mechanisms by which they control excitation-contraction coupling, excitability, and arrhythmias are less clear. The translocator protein (TSPO) is an outer mitochondrial membrane protein that is expressed in multiple organ systems. The abundant expression of TSPO in macrophages has been leveraged to image the immune response of the heart to inflammatory processes. More recently, the recognition of TSPO as a regulator of energy-dissipating mitochondrial pathways has extended its utility from a diagnostic marker of inflammation to a therapeutic target influencing diverse pathophysiological processes. Here, we provide an overview of the emerging role of TSPO in ischemic heart disease. We highlight the importance of TSPO in the regenerative process of reactive oxygen species (ROS) induced ROS release through its effects on the inner membrane anion channel (IMAC) and the permeability transition pore (PTP). We discuss evidence implicating TSPO in arrhythmogenesis in the settings of acute ischemia-reperfusion injury and myocardial infarction.
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Role of NADPH oxidase and xanthine oxidase in mediating inducible VT/VF and triggered activity in a canine model of myocardial ischemia. Int J Mol Sci 2014; 15:20079-100. [PMID: 25375191 PMCID: PMC4264157 DOI: 10.3390/ijms151120079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 10/17/2014] [Accepted: 10/21/2014] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Ventricular tachycardia or fibrillation (VT/VF) of focal origin due to triggered activity (TA) from delayed afterdepolarizations (DADs) is reproducibly inducible after anterior coronary artery occlusion. Both VT/VF and TA can be blocked by reducing reactive oxygen species (ROS). We tested the hypothesis that inhibition of NADPH oxidase and xanthine oxidase would block VT/VF. METHODS 69 dogs received apocynin (APO), 4 mg/kg intraveneously (IV), oxypurinol (OXY), 4 mg/kg IV, or both APO and OXY (BOTH) agents, or saline 3 h after coronary occlusion. Endocardium from ischemic sites (3-D mapping) was sampled for Rac1 (GTP-binding protein in membrane NADPH oxidase) activation or standard microelectrode techniques. Results (mean±SE, * p<0.05): VT/VF originating from ischemic zones was blocked by APO in 6/10 *, OXY in 4/9 *, BOTH in 5/8 * or saline in 1/27; 11/16 VT/VFs blocked were focal. In isolated myocardium, TA was blocked by APO (10(-6) M) or OXY (10(-8) M). Rac1 levels in ischemic endocardium were decreased by APO or OXY. CONCLUSION APO and OXY suppressed focal VT/VF due to DADs, but the combination of the drugs was not more effective than either alone. Both drugs inhibited ischemic Rac1 with inhibition by OXY suggesting ROS-induced ROS. The inability to totally prevent VT/VF suggests that other mechanisms also contribute to ischemic VT.
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Zorov DB, Juhaszova M, Sollott SJ. Mitochondrial reactive oxygen species (ROS) and ROS-induced ROS release. Physiol Rev 2014; 94:909-50. [PMID: 24987008 DOI: 10.1152/physrev.00026.2013] [Citation(s) in RCA: 3187] [Impact Index Per Article: 318.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca(2+), etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca(2+)). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo.
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Affiliation(s)
- Dmitry B Zorov
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Magdalena Juhaszova
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Steven J Sollott
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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O-Uchi J, Ryu SY, Jhun BS, Hurst S, Sheu SS. Mitochondrial ion channels/transporters as sensors and regulators of cellular redox signaling. Antioxid Redox Signal 2014; 21:987-1006. [PMID: 24180309 PMCID: PMC4116125 DOI: 10.1089/ars.2013.5681] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE Mitochondrial ion channels/transporters and the electron transport chain (ETC) serve as key sensors and regulators for cellular redox signaling, the production of reactive oxygen species (ROS) and nitrogen species (RNS) in mitochondria, and balancing cell survival and death. Although the functional and pharmacological characteristics of mitochondrial ion transport mechanisms have been extensively studied for several decades, the majority of the molecular identities that are responsible for these channels/transporters have remained a mystery until very recently. RECENT ADVANCES Recent breakthrough studies uncovered the molecular identities of the diverse array of major mitochondrial ion channels/transporters, including the mitochondrial Ca2+ uniporter pore, mitochondrial permeability transition pore, and mitochondrial ATP-sensitive K+ channel. This new information enables us to form detailed molecular and functional characterizations of mitochondrial ion channels/transporters and their roles in mitochondrial redox signaling. CRITICAL ISSUES Redox-mediated post-translational modifications of mitochondrial ion channels/transporters and ETC serve as key mechanisms for the spatiotemporal control of mitochondrial ROS/RNS generation. FUTURE DIRECTIONS Identification of detailed molecular mechanisms for redox-mediated regulation of mitochondrial ion channels will enable us to find novel therapeutic targets for many diseases that are associated with cellular redox signaling and mitochondrial ion channels/transporters.
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Affiliation(s)
- Jin O-Uchi
- 1 Department of Medicine, Center for Translational Medicine, Jefferson Medical College, Thomas Jefferson University , Philadelphia, Pennsylvania
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Xie C, Kauffman J, Akar FG. Functional crosstalk between the mitochondrial PTP and KATP channels determine arrhythmic vulnerability to oxidative stress. Front Physiol 2014; 5:264. [PMID: 25076913 PMCID: PMC4099963 DOI: 10.3389/fphys.2014.00264] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/24/2014] [Indexed: 01/18/2023] Open
Abstract
Background: Mitochondrial permeability transition pore (mPTP) opening is a terminal event leading to mitochondrial dysfunction and cell death under conditions of oxidative stress (OS). However, mPTP blockade with cyclosporine A (CsA) has shown variable efficacy in limiting post-ischemic dysfunction and arrhythmias. We hypothesized that strong feedback between energy dissipating (mPTP) and cardioprotective (mKATP) channels determine vulnerability to OS. Methods and Results: Guinea pig hearts (N = 61) were challenged with H2O2 (200 μM) to elicit mitochondrial membrane potential (ΔΨm) depolarization. High-resolution optical mapping was used to measure ΔΨm or action potentials (AP) across the intact heart. Hearts were treated with CsA (0.1 μM) under conditions that altered the activity of mKATP channels either directly or indirectly via its regulation by protein kinase C. mPTP blockade with CsA markedly blunted (P < 0.01) OS-induced ΔΨm depolarization and delayed loss of LV pressure (LVP), but did not affect arrhythmia propensity. Surprisingly, prevention of mKATP activation with the chemical phosphatase BDM reversed the protective effect of CsA, paradoxically exacerbating OS-induced ΔΨm depolarization and accelerating arrhythmia onset in CsA treated compared to untreated hearts (P < 0.05). To elucidate the putative molecular mechanisms, mPTP inhibition by CsA was tested during conditions of selective PKC inhibition or direct mKATP channel activation or blockade. Similar to BDM, the specific PKC inhibitor, CHE (10 μM) did not alter OS-induced ΔΨm depolarization directly. However, it completely abrogated CsA-mediated protection against OS. Direct pharmacological blockade of mKATP, a mitochondrial target of PKC signaling, equally abolished the protective effect of CsA on ΔΨm depolarization, whereas channel activation with 30 μM Diazoxide protected against ΔΨm depolarization (P < 0.0001). Conditions that prevented mKATP activation either directly or indirectly via PKC inhibition led to accelerated ΔΨm depolarization and early onset of VF in response to OS. Investigation of the electrophysiological substrate revealed accelerated APD shortening in response to OS in arrhythmia-prone hearts. Conclusions: Cardioprotection by CsA requires mKATP channel activation through a PKC-dependent pathway. Increasing mKATP activity during CsA administration is required for limiting OS-induced electrical dysfunction.
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Affiliation(s)
- Chaoqin Xie
- Department of Medicine, Cardiovascular Institute, Mount Sinai School of Medicine New York, NY, USA
| | - Justin Kauffman
- Department of Medicine, Cardiovascular Institute, Mount Sinai School of Medicine New York, NY, USA
| | - Fadi G Akar
- Department of Medicine, Cardiovascular Institute, Mount Sinai School of Medicine New York, NY, USA
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Abstract
The field of mitochondrial ion channels has recently seen substantial progress, including the molecular identification of some of the channels. An integrative approach using genetics, electrophysiology, pharmacology, and cell biology to clarify the roles of these channels has thus become possible. It is by now clear that many of these channels are important for energy supply by the mitochondria and have a major impact on the fate of the entire cell as well. The purpose of this review is to provide an up-to-date overview of the electrophysiological properties, molecular identity, and pathophysiological functions of the mitochondrial ion channels studied so far and to highlight possible therapeutic perspectives based on current information.
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Mitochondrial targets for arrhythmia suppression: is there a role for pharmacological intervention? J Interv Card Electrophysiol 2013; 37:249-58. [PMID: 23824789 DOI: 10.1007/s10840-013-9809-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/03/2013] [Indexed: 12/19/2022]
Abstract
Mitochondrial dysfunction is a hallmark of common cardiovascular disorders, including ischemia-reperfusion injury, hypertrophy, heart failure, and diabetes mellitus. While the role of the mitochondrial network in regulating energy production and cell death pathways is well established, its active control of other critical cellular functions, including excitation-contraction coupling and excitability, is less understood. The purpose of this focused review article is to highlight the growing mechanistic link between mitochondrial dysfunction and arrhythmogenesis. The goal is not to provide a comprehensive listing of all factors by which mitochondrial bioenergetics and altered cellular redox status affect ion channel function but rather to focus on one central mechanism of arrhythmogenesis which arises from a mitochondrial origin. In doing so, we discuss the role of mitochondrial targets for suppressing arrhythmias through this mechanism.
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Xie C, Biary N, Tocchetti CG, Aon MA, Paolocci N, Kauffman J, Akar FG. Glutathione oxidation unmasks proarrhythmic vulnerability of chronically hyperglycemic guinea pigs. Am J Physiol Heart Circ Physiol 2013; 304:H916-26. [PMID: 23376824 DOI: 10.1152/ajpheart.00026.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Chronic hyperglycemia in type-1 diabetes mellitus is associated with oxidative stress (OS) and sudden death. Mechanistic links remain unclear. We investigated changes in electrophysiological (EP) properties in a model of chronic hyperglycemia before and after challenge with OS by GSH oxidation and tested reversibility of EP remodeling by insulin. Guinea pigs survived for 1 mo following streptozotocin (STZ) or saline (sham) injection. A treatment group received daily insulin for 2 wk to reverse STZ-induced hyperglycemia (STZ + Ins). EP properties were measured using high-resolution optical action potential mapping before and after challenge of hearts with diamide. Despite elevation of glucose levels in STZ compared with sham-operated (P = 0.004) and STZ + Ins (P = 0.002) animals, average action potential duration (APD) and arrhythmia propensity were not altered at baseline. Diamide promoted early (<10 min) formation of arrhythmic triggers reflected by a higher arrhythmia scoring index in STZ (P = 0.045) and STZ + Ins (P = 0.033) hearts compared with sham-operated hearts. APD heterogeneity underwent a more pronounced increase in response to diamide in STZ and STZ + Ins hearts compared with sham-operated hearts. Within 30 min, diamide resulted in spontaneous incidence of ventricular tachycardia and ventricular fibrillation (VT/VF) in 3/6, 2/5, 1/5, and 0/4 STZ, STZ + Ins, sham-operated, and normal hearts, respectively. Hearts prone to VT/VF exhibited greater APD heterogeneity (P = 0.010) compared with their VT/VF-free counterparts. Finally, altered EP properties in STZ were not rescued by insulin. In conclusion, GSH oxidation enhances APD heterogeneity and increases arrhythmia scoring index in a guinea pig model of chronic hyperglycemia. Despite normalization of glycemic levels by insulin, these proarrhythmic properties are not reversed, suggesting the importance of targeting antioxidant defenses for arrhythmia suppression.
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Affiliation(s)
- Chaoqin Xie
- Cardiovascular Institute, Mount Sinai School of Medicine, New York, NY 10029, USA
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Potential implication of the chemical properties and bioactivity of nitrone spin traps for therapeutics. Future Med Chem 2012; 4:1171-207. [PMID: 22709256 DOI: 10.4155/fmc.12.74] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nitrone therapeutics has been employed in the treatment of oxidative stress-related diseases such as neurodegeneration, cardiovascular disease and cancer. The nitrone-based compound NXY-059, which is the first drug to reach clinical trials for the treatment of acute ischemic stroke, has provided promise for the development of more robust pharmacological agents. However, the specific mechanism of nitrone bioactivity remains unclear. In this review, we present a variety of nitrone chemistry and biological activity that could be implicated for the nitrone's pharmacological activity. The chemistries of spin trapping and spin adduct reveal insights on the possible roles of nitrones for altering cellular redox status through radical scavenging or nitric oxide donation, and their biological effects are presented. An interdisciplinary approach towards the development of novel synthetic antioxidants with improved pharmacological properties encompassing theoretical, synthetic, biochemical and in vitro/in vivo studies is covered.
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Aon MA, Cortassa S. Mitochondrial network energetics in the heart. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2012; 4:599-613. [PMID: 22899654 DOI: 10.1002/wsbm.1188] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
At the core of eukaryotic aerobic life, mitochondrial function like 'hubs' in the web of energetic and redox processes in cells. In the heart, these networks-extending beyond the complex connectivity of biochemical circuit diagrams and apparent morphology-exhibit collective dynamics spanning several spatiotemporal levels of organization, from the cell, to the tissue, and the organ. The network function of mitochondria, i.e., mitochondrial network energetics, represents an advantageous behavior. Its coordinated action, under normal physiology, provides robustness despite failure in a few nodes, and improves energy supply toward a swiftly changing demand. Extensive diffuse loops, encompassing mitochondrial-cytoplasmic reaction/transport networks, control and regulate energy supply and demand in the heart. Under severe energy crises, the network behavior of mitochondria and associated glycolytic and other metabolic networks collapse, thereby triggering fatal arrhythmias.
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Affiliation(s)
- Miguel A Aon
- Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA.
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Liao R, Podesser BK, Lim CC. The continuing evolution of the Langendorff and ejecting murine heart: new advances in cardiac phenotyping. Am J Physiol Heart Circ Physiol 2012; 303:H156-67. [PMID: 22636675 DOI: 10.1152/ajpheart.00333.2012] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The isolated retrograde-perfused Langendorff heart and the isolated ejecting heart have, over many decades, resulted in fundamental discoveries that form the underpinnings of our current understanding of the biology and physiology of the heart. These two experimental methodologies have proven invaluable in studying pharmacological effects on myocardial function, metabolism, and vascular reactivity and in the investigation of clinically relevant disease states such as ischemia-reperfusion injury, diabetes, obesity, and heart failure. With the advent of the genomics era, the isolated mouse heart preparation has gained prominence as an ex vivo research tool for investigators studying the impact of gene modification in the intact heart. This review summarizes the historical development of the isolated heart and provides a practical guide for the establishment of the Langendorff and ejecting heart preparations with a particular emphasis on the murine heart. In addition, current applications and novel methods of recording cardiovascular parameters in the isolated heart preparation will be discussed. With continued advances in methodological recordings, the isolated mouse heart preparation will remain physiologically relevant for the foreseeable future, serving as an integral bridge between in vitro assays and in vivo approaches.
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Affiliation(s)
- Ronglih Liao
- Cardiac Muscle Research Laboratory, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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Aon MA, Stanley BA, Sivakumaran V, Kembro JM, O'Rourke B, Paolocci N, Cortassa S. Glutathione/thioredoxin systems modulate mitochondrial H2O2 emission: an experimental-computational study. ACTA ACUST UNITED AC 2012; 139:479-91. [PMID: 22585969 PMCID: PMC3362521 DOI: 10.1085/jgp.201210772] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The net emission of hydrogen peroxide (H(2)O(2)) from mitochondria results from the balance between reactive oxygen species (ROS) continuously generated in the respiratory chain and ROS scavenging. The relative contribution of the two major antioxidant systems in the mitochondrial matrix, glutathione (GSH) and thioredoxin (Trx), has not been assessed. In this paper, we examine this key question via combined experimental and theoretical approaches, using isolated heart mitochondria from mouse, rat, and guinea pig. As compared with untreated control mitochondria, selective inhibition of Trx reductase with auranofin along with depletion of GSH with 2,4-dinitrochlorobenzene led to a species-dependent increase in H(2)O(2) emission flux of 17, 11, and 6 fold in state 4 and 15, 7, and 8 fold in state 3 for mouse, rat, and guinea pig mitochondria, respectively. The maximal H(2)O(2) emission as a percentage of the total O(2) consumption flux was 11%/2.3% for mouse in states 4 and 3 followed by 2%/0.25% and 0.74%/0.29% in the rat and guinea pig, respectively. A minimal computational model accounting for the kinetics of GSH/Trx systems was developed and was able to simulate increase in H(2)O(2) emission fluxes when both scavenging systems were inhibited separately or together. Model simulations suggest that GSH/Trx systems act in concert. When the scavenging capacity of either one of them saturates during H(2)O(2) overload, they relieve each other until complete saturation, when maximal ROS emission occurs. Quantitatively, these results converge on the idea that GSH/Trx scavenging systems in mitochondria are both essential for keeping minimal levels of H(2)O(2) emission, especially during state 3 respiration, when the energetic output is maximal. This suggests that the very low levels of H(2)O(2) emission observed during forward electron transport in the respiratory chain are a result of the well-orchestrated actions of the two antioxidant systems working continuously to offset ROS production.
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Affiliation(s)
- Miguel Antonio Aon
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Sovari AA. Antioxidant therapy for atrial fibrillation: what is the next step? Cardiol Res Pract 2011; 2011:429537. [PMID: 22111027 PMCID: PMC3216288 DOI: 10.4061/2011/429537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 09/22/2011] [Indexed: 11/20/2022] Open
Affiliation(s)
- Ali A Sovari
- Section of Cardiology, Center for Cardiovascular Research, University of Illinois at Chicago, 840 S. Wood Street, MC 715, Chicago, IL 60612, USA
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