201
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Gottlieb RA, Bernstein D. Mitochondrial remodeling: Rearranging, recycling, and reprogramming. Cell Calcium 2016; 60:88-101. [PMID: 27130902 PMCID: PMC4996709 DOI: 10.1016/j.ceca.2016.04.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/15/2016] [Accepted: 04/17/2016] [Indexed: 12/26/2022]
Abstract
Mitochondria are highly dynamic and responsive organelles that respond to environmental cues with fission and fusion. They undergo mitophagy and biogenesis, and are subject to extensive post-translational modifications. Calcium plays an important role in regulating mitochondrial functions. Mitochondria play a central role in metabolism of glucose, fatty acids, and amino acids, and generate ATP with effects on redox poise, oxidative stress, pH, and other metabolites including acetyl-CoA and NAD(+) which in turn have effects on chromatin remodeling. The complex interplay of mitochondria, cytosolic factors, and the nucleus ensure a well-coordinated response to environmental stresses.
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Affiliation(s)
| | - Daniel Bernstein
- Department of Pediatrics (Cardiology) and the Cardiovascular Institute, Stanford University, Stanford, CA, United States
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202
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Ishikita A, Matoba T, Ikeda G, Koga JI, Mao Y, Nakano K, Takeuchi O, Sadoshima J, Egashira K. Nanoparticle-Mediated Delivery of Mitochondrial Division Inhibitor 1 to the Myocardium Protects the Heart From Ischemia-Reperfusion Injury Through Inhibition of Mitochondria Outer Membrane Permeabilization: A New Therapeutic Modality for Acute Myocardial Infarction. J Am Heart Assoc 2016; 5:e003872. [PMID: 27451459 PMCID: PMC5015412 DOI: 10.1161/jaha.116.003872] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/21/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Mitochondria-mediated cell death plays a critical role in myocardial ischemia-reperfusion (IR) injury. We hypothesized that nanoparticle-mediated drug delivery of mitochondrial division inhibitor 1 (Mdivi1) protects hearts from IR injury through inhibition of mitochondria outer membrane permeabilization (MOMP), which causes mitochondrial-mediated cell death. METHODS AND RESULTS We formulated poly (lactic-co-glycolic acid) nanoparticles containing Mdivi1 (Mdivi1-NP). We recently demonstrated that these nanoparticles could be successfully delivered to the cytosol and mitochondria of cardiomyocytes under H2O2-induced oxidative stress that mimicked IR injury. Pretreatment with Mdivi1-NP ameliorated H2O2-induced cell death in rat neonatal cardiomyocytes more potently than Mdivi1 alone, as indicated by a lower estimated half-maximal effective concentration and greater maximal effect on cell survival. Mdivi1-NP treatment of Langendorff-perfused mouse hearts through the coronary arteries at the time of reperfusion reduced infarct size after IR injury more effectively than Mdivi1 alone. Mdivi1-NP treatment also inhibited Drp1-mediated Bax translocation to the mitochondria and subsequent cytochrome c leakage into the cytosol, namely, MOMP, in mouse IR hearts. MOMP inhibition was also observed in cyclophilin D knockout (CypD-KO) mice, which lack the mitochondrial permeability transition pore (MPTP) opening. Intravenous Mdivi1-NP treatment in vivo at the time of reperfusion reduced IR injury in wild-type and CypD-KO mice, but not Bax-KO mice. CONCLUSIONS Mdivi1-NP treatment reduced IR injury through inhibition of MOMP, even in the absence of a CypD/MPTP opening. Thus, nanoparticle-mediated drug delivery of Mdivi1 may be a novel treatment strategy for IR injury.
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Affiliation(s)
- Ayako Ishikita
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Tetsuya Matoba
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Gentaro Ikeda
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Jun-Ichiro Koga
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan Department of Cardiovascular Research, Development, and Translational Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Yajing Mao
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Kaku Nakano
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan Department of Cardiovascular Research, Development, and Translational Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Osamu Takeuchi
- Labolatory of Infection and Prevention, Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, NJ
| | - Kensuke Egashira
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan Department of Cardiovascular Research, Development, and Translational Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
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203
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Liang Q, Kobayashi S. Mitochondrial quality control in the diabetic heart. J Mol Cell Cardiol 2016; 95:57-69. [PMID: 26739215 PMCID: PMC6263145 DOI: 10.1016/j.yjmcc.2015.12.025] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/03/2015] [Accepted: 12/26/2015] [Indexed: 02/07/2023]
Abstract
Diabetes is a well-known risk factor for heart failure. Diabetic heart damage is closely related to mitochondrial dysfunction and increased ROS generation. However, clinical trials have shown no effects of antioxidant therapies on heart failure in diabetic patients, suggesting that simply antagonizing existing ROS by antioxidants is not sufficient to reduce diabetic cardiac injury. A potentially more effective treatment strategy may be to enhance the overall capacity of mitochondrial quality control to maintain a pool of healthy mitochondria that are needed for supporting cardiac contractile function in diabetic patients. Mitochondrial quality is controlled by a number of coordinated mechanisms including mitochondrial fission and fusion, mitophagy and biogenesis. The mitochondrial damage consistently observed in the diabetic hearts indicates a failure of the mitochondrial quality control mechanisms. Recent studies have demonstrated a crucial role for each of these mechanisms in cardiac homeostasis and have begun to interrogate the relative contribution of insufficient mitochondrial quality control to diabetic cardiac injury. In this review, we will present currently available literature that links diabetic heart disease to the dysregulation of major mitochondrial quality control mechanisms. We will discuss the functional roles of these mechanisms in the pathogenesis of diabetic heart disease and their potentials for targeted therapeutical manipulation.
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Affiliation(s)
- Qiangrong Liang
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA.
| | - Satoru Kobayashi
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
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204
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Altered mitochondrial expression genes in patients receiving right ventricular apical pacing. Exp Mol Pathol 2016; 100:469-75. [DOI: 10.1016/j.yexmp.2016.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 05/09/2016] [Accepted: 05/09/2016] [Indexed: 11/22/2022]
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205
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Hall AR, Burke N, Dongworth RK, Kalkhoran SB, Dyson A, Vicencio JM, Dorn GW, Yellon DM, Hausenloy DJ. Hearts deficient in both Mfn1 and Mfn2 are protected against acute myocardial infarction. Cell Death Dis 2016; 7:e2238. [PMID: 27228353 PMCID: PMC4917668 DOI: 10.1038/cddis.2016.139] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/18/2016] [Accepted: 04/19/2016] [Indexed: 01/26/2023]
Abstract
Mitochondria alter their shape by undergoing cycles of fusion and fission. Changes in mitochondrial morphology impact on the cellular response to stress, and their interactions with other organelles such as the sarcoplasmic reticulum (SR). Inhibiting mitochondrial fission can protect the heart against acute ischemia/reperfusion (I/R) injury. However, the role of the mitochondrial fusion proteins, Mfn1 and Mfn2, in the response of the adult heart to acute I/R injury is not clear, and is investigated in this study. To determine the effect of combined Mfn1/Mfn2 ablation on the susceptibility to acute myocardial I/R injury, cardiac-specific ablation of both Mfn1 and Mfn2 (DKO) was initiated in mice aged 4-6 weeks, leading to knockout of both these proteins in 8-10-week-old animals. This resulted in fragmented mitochondria (electron microscopy), decreased mitochondrial respiratory function (respirometry), and impaired myocardial contractile function (echocardiography). In DKO mice subjected to in vivo regional myocardial ischemia (30 min) followed by 24 h reperfusion, myocardial infarct size (IS, expressed as a % of the area-at-risk) was reduced by 46% compared with wild-type (WT) hearts. In addition, mitochondria from DKO animals had decreased MPTP opening susceptibility (assessed by Ca(2+)-induced mitochondrial swelling), compared with WT hearts. Mfn2 is a key mediator of mitochondrial/SR tethering, and accordingly, the loss of Mfn2 in DKO hearts reduced the number of interactions measured between these organelles (quantified by proximal ligation assay), attenuated mitochondrial calcium overload (Rhod2 confocal microscopy), and decreased reactive oxygen species production (DCF confocal microscopy) in response to acute I/R injury. No differences in isolated mitochondrial ROS emissions (Amplex Red) were detected in response to Ca(2+) and Antimycin A, further implicating disruption of mitochondria/SR tethering as the protective mechanism. In summary, despite apparent mitochondrial dysfunction, hearts deficient in both Mfn1 and Mfn2 are protected against acute myocardial infarction due to impaired mitochondria/SR tethering.
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Affiliation(s)
- A R Hall
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - N Burke
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - R K Dongworth
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - S B Kalkhoran
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - A Dyson
- Division of Medicine, University College London, London, UK
| | - J M Vicencio
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - G W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - D M Yellon
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - D J Hausenloy
- The Hatter Cardiovascular Institute, University College London, London, UK.,Cardiovascular and Metabolic Disorders Program, Duke-National University Singapore Graduate Medical School, Singapore, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
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206
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Tang Y, Liu X, Zhao J, Tan X, Liu B, Zhang G, Sun L, Han D, Chen H, Wang M. Hypothermia-induced ischemic tolerance is associated with Drp1 inhibition in cerebral ischemia-reperfusion injury of mice. Brain Res 2016; 1646:73-83. [PMID: 27235868 DOI: 10.1016/j.brainres.2016.05.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/22/2016] [Accepted: 05/24/2016] [Indexed: 01/04/2023]
Abstract
Excessive mitochondrial fission activation has been implicated in cerebral ischemia-reperfusion (IR) injury. Hypothermia is effective in preventing cerebral ischemic damage. However, effects of hypothermia on ischemia-induced mitochondrial fission activation is not well known. Therefore, the aim of this study was to investigate whether hypothermia protect the brain by inhibiting mitochondrial fission-related proteins activation following cerebral IR injury. Adult male C57BL/6 mice were subjected to transient forebrain ischemia induced by 15min of bilateral common carotid artery occlusion (BCCAO). Mice were divided into three groups (n=48 each): Hypothermia (HT) group, with mild hypothermia (32-34°C) for 4h; Normothermia (NT) group, similarly as HT group except for cooling; Sham group, with vessels exposed but without occlusion or cooling. Hematoxylin and eosin (HE), Nissl staining, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and behavioral testing (n=6 each) demonstrated that hypothermia significantly decreased ischemia-induced neuronal injury. The expressions of Dynamin related protein 1 (Drp1) and Cytochrome C (Cyto C) (n=6 each) in mice hippocampus were measured at 3, 6, 24, and 72h of reperfusion. IR injury significantly increased expressions of total Drp1, phosphorylated Drp1 (P-Drp1 S616) and Cyto C under normothermia. However, mild hypothermia inhibited Drp1 activation and Cyto C cytosolic release, preserved neural cells integrity and reduced neuronal necrosis and apoptosis. These findings indicated that mild hypothermia-induced neuroprotective effects against ischemia-reperfusion injury is associated with suppressing mitochondrial fission-related proteins activation and apoptosis execution.
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Affiliation(s)
- Yingying Tang
- Department of Anesthesiology, Qingdao Municipal Hospital, Dalian Medical University, Dalian, China; Department of Anesthesiology, Women's Hospital, School of Medicine, Zhejiang University, Xueshi Road 1, Hangzhou, Zhejiang 310006, China
| | - Xiaojie Liu
- Department of Anesthesiology, Qingdao Central Hospital, Shandong, China
| | - Jie Zhao
- Department of Anesthesiology, Qingdao Municipal Hospital, Dalian Medical University, Dalian, China
| | - Xueying Tan
- Department of Hepatobiliary Surgery, Qingdao Municipal Hospital, Shandong, China
| | - Bing Liu
- Department of Anesthesiology, Qingdao Municipal Hospital, Dalian Medical University, Dalian, China
| | - Gaofeng Zhang
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Shandong, China
| | - Lixin Sun
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Shandong, China
| | - Dengyang Han
- Department of Anesthesiology, Qingdao Municipal Hospital, Dalian Medical University, Dalian, China
| | - Huailong Chen
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Shandong, China.
| | - Mingshan Wang
- Department of Anesthesiology, Qingdao Municipal Hospital, Dalian Medical University, Dalian, China; Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Shandong, China.
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207
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Autophagy, Innate Immunity and Tissue Repair in Acute Kidney Injury. Int J Mol Sci 2016; 17:ijms17050662. [PMID: 27153058 PMCID: PMC4881488 DOI: 10.3390/ijms17050662] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/14/2016] [Accepted: 04/20/2016] [Indexed: 01/09/2023] Open
Abstract
Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI) is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed.
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208
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Paradis S, Charles AL, Meyer A, Lejay A, Scholey JW, Chakfé N, Zoll J, Geny B. Chronology of mitochondrial and cellular events during skeletal muscle ischemia-reperfusion. Am J Physiol Cell Physiol 2016; 310:C968-82. [PMID: 27076618 DOI: 10.1152/ajpcell.00356.2015] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Peripheral artery disease (PAD) is a common circulatory disorder of the lower limb arteries that reduces functional capacity and quality of life of patients. Despite relatively effective available treatments, PAD is a serious public health issue associated with significant morbidity and mortality. Ischemia-reperfusion (I/R) cycles during PAD are responsible for insufficient oxygen supply, mitochondriopathy, free radical production, and inflammation and lead to events that contribute to myocyte death and remote organ failure. However, the chronology of mitochondrial and cellular events during the ischemic period and at the moment of reperfusion in skeletal muscle fibers has been poorly reviewed. Thus, after a review of the basal myocyte state and normal mitochondrial biology, we discuss the physiopathology of ischemia and reperfusion at the mitochondrial and cellular levels. First we describe the chronology of the deleterious biochemical and mitochondrial mechanisms activated by I/R. Then we discuss skeletal muscle I/R injury in the muscle environment, mitochondrial dynamics, and inflammation. A better understanding of the chronology of the events underlying I/R will allow us to identify key factors in the development of this pathology and point to suitable new therapies. Emerging data on mitochondrial dynamics should help identify new molecular and therapeutic targets and develop protective strategies against PAD.
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Affiliation(s)
- Stéphanie Paradis
- University of Strasbourg, Fédération de Médecine Translationelle, EA 3072, Strasbourg, France; Department of Physiology and Functional Explorations, Thoracic Pathology Unit, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France;
| | - Anne-Laure Charles
- University of Strasbourg, Fédération de Médecine Translationelle, EA 3072, Strasbourg, France; Department of Physiology and Functional Explorations, Thoracic Pathology Unit, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Alain Meyer
- University of Strasbourg, Fédération de Médecine Translationelle, EA 3072, Strasbourg, France; Department of Physiology and Functional Explorations, Thoracic Pathology Unit, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Anne Lejay
- University of Strasbourg, Fédération de Médecine Translationelle, EA 3072, Strasbourg, France; Department of Physiology and Functional Explorations, Thoracic Pathology Unit, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; Department of Vascular Surgery and Kidney Transplantation, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; and
| | - James W Scholey
- Department of Medicine and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Nabil Chakfé
- University of Strasbourg, Fédération de Médecine Translationelle, EA 3072, Strasbourg, France; Department of Vascular Surgery and Kidney Transplantation, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; and
| | - Joffrey Zoll
- University of Strasbourg, Fédération de Médecine Translationelle, EA 3072, Strasbourg, France; Department of Physiology and Functional Explorations, Thoracic Pathology Unit, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Bernard Geny
- University of Strasbourg, Fédération de Médecine Translationelle, EA 3072, Strasbourg, France; Department of Physiology and Functional Explorations, Thoracic Pathology Unit, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
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209
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Mitochondrial fission/fusion and cardiomyopathy. Curr Opin Genet Dev 2016; 38:38-44. [PMID: 27061490 DOI: 10.1016/j.gde.2016.03.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/23/2016] [Accepted: 03/04/2016] [Indexed: 01/08/2023]
Abstract
Mitochondria are highly abundant in and essential to the beat-to-beat contractile performance of hearts. However, relatively few cardiac diseases have been attributed to primary mitochondrial dysfunction. The paucity of evidence for 'primary mitochondrial cardiac diseases' may be because such an entity does not exist. Alternately, the consequences of mitochondrial dysfunction on hearts may be so severe that long-term viability is severely impaired and affected individuals are therefore not included in standard genetic screens of adult heart disease subjects. Here, I review accumulating experimental evidence that impairing mitochondrial fission or fusion causes cardiomyopathy in otherwise normal mice, and consider how these data could motivate screening of perinatal cardiomyopathy subjects for damaging mutations of mitochondrial fission and fusion factors.
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210
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Abstract
Mitochondria of adult cardiomyocytes appear hypo-dynamic, lacking interconnected reticular networks and the continual fission and fusion observed in many other cell types. Nevertheless, proteins essential to mitochondrial network remodeling are abundant in adult hearts. Recent findings from cardiac-specific ablation of mitochondrial fission and fusion protein genes have revealed unexpected roles for mitochondrial dynamics factors in mitophagic mitochondrial quality control. This overview examines the clinical and experimental evidence for and against a meaningful role for the mitochondrial dynamism-quality control interactome in normal and diseased hearts. Newly discovered functions of mitochondrial dynamics factors in maintaining optimal cardiac mitochondrial fitness suggest that deep interrogation of clinical cardiomyopathy is likely to reveal genetic variants that cause or modify cardiac disease through their effects on mitochondrial fission, fusion, and mitophagy.
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Affiliation(s)
- Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
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211
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Walters JW, Amos D, Ray K, Santanam N. Mitochondrial redox status as a target for cardiovascular disease. Curr Opin Pharmacol 2016; 27:50-5. [PMID: 26894468 DOI: 10.1016/j.coph.2016.01.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/25/2016] [Accepted: 01/29/2016] [Indexed: 02/07/2023]
Abstract
Mitochondria are major players in cellular energetics, oxidative stress and programmed cell death. Mitochondrial dynamics regulate and integrate these functions. Mitochondrial dysfunction is involved in cardiac hypertrophy, hypertension and myocardial ischemia/reperfusion injury. Reactive oxygen species generation is modulated by the fusion-fission pathway as well as key proteins such as sirtuins that act as metabolic sensors of cellular energetics. Mitochondrial redox status has thus become a good target for therapy against cardiovascular diseases. Recently, there is an influx of studies garnered towards assessing the beneficial effects of mitochondrial targeted antioxidants, drugs modulating the fusion-fission proteins, sirtuins, and other mitochondrial processes as potential cardio-protecting agents.
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Affiliation(s)
- James W Walters
- School of Arts & Sciences, Bluefield State College, Basic Science Building B213, 219 Rock Street, Bluefield, WV 24701, USA
| | - Deborah Amos
- Department of Pharmacology, Physiology & Toxicology, Joan C Edwards School of Medicine, Marshall University, One John Marshall Dr, Huntington, WV 25755, USA
| | - Kristeena Ray
- Department of Pharmacology, Physiology & Toxicology, Joan C Edwards School of Medicine, Marshall University, One John Marshall Dr, Huntington, WV 25755, USA
| | - Nalini Santanam
- Department of Pharmacology, Physiology & Toxicology, Joan C Edwards School of Medicine, Marshall University, One John Marshall Dr, Huntington, WV 25755, USA.
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212
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213
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Vásquez-Trincado C, García-Carvajal I, Pennanen C, Parra V, Hill JA, Rothermel BA, Lavandero S. Mitochondrial dynamics, mitophagy and cardiovascular disease. J Physiol 2016; 594:509-25. [PMID: 26537557 DOI: 10.1113/jp271301] [Citation(s) in RCA: 399] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/30/2015] [Indexed: 12/14/2022] Open
Abstract
Cardiac hypertrophy is often initiated as an adaptive response to haemodynamic stress or myocardial injury, and allows the heart to meet an increased demand for oxygen. Although initially beneficial, hypertrophy can ultimately contribute to the progression of cardiac disease, leading to an increase in interstitial fibrosis and a decrease in ventricular function. Metabolic changes have emerged as key mechanisms involved in the development and progression of pathological remodelling. As the myocardium is a highly oxidative tissue, mitochondria play a central role in maintaining optimal performance of the heart. 'Mitochondrial dynamics', the processes of mitochondrial fusion, fission, biogenesis and mitophagy that determine mitochondrial morphology, quality and abundance have recently been implicated in cardiovascular disease. Studies link mitochondrial dynamics to the balance between energy demand and nutrient supply, suggesting that changes in mitochondrial morphology may act as a mechanism for bioenergetic adaptation during cardiac pathological remodelling. Another critical function of mitochondrial dynamics is the removal of damaged and dysfunctional mitochondria through mitophagy, which is dependent on the fission/fusion cycle. In this article, we discuss the latest findings regarding the impact of mitochondrial dynamics and mitophagy on the development and progression of cardiovascular pathologies, including diabetic cardiomyopathy, atherosclerosis, damage from ischaemia-reperfusion, cardiac hypertrophy and decompensated heart failure. We will address the ability of mitochondrial fusion and fission to impact all cell types within the myocardium, including cardiac myocytes, cardiac fibroblasts and vascular smooth muscle cells. Finally, we will discuss how these findings can be applied to improve the treatment and prevention of cardiovascular diseases.
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Affiliation(s)
- César Vásquez-Trincado
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile
| | - Ivonne García-Carvajal
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile
| | - Christian Pennanen
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile
| | - Valentina Parra
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Joseph A Hill
- Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA.,Department of Molecular Biology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Beverly A Rothermel
- Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA.,Department of Molecular Biology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Sergio Lavandero
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA
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214
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Abstract
Mitochondria are an essential component of multicellular life - from primitive organisms, to highly complex entities like mammals. The importance of mitochondria is underlined by their plethora of well-characterized essential functions such as energy production through oxidative phosphorylation (OX-PHOS), calcium and reactive oxygen species (ROS) signaling, and regulation of apoptosis. In addition, novel roles and attributes of mitochondria are coming into focus through the recent years of mitochondrial research. In particular, over the past decade the study of mitochondrial shape and dynamics has achieved special significance, as they are found to impact mitochondrial function. Recent advances indicate that mitochondrial function and dynamics are inter-connected, and maintain the balance between health and disease at a cellular and an organismal level. For example, excessive mitochondrial division (fission) is associated with functional defects, and is implicated in multiple human diseases from neurodegenerative diseases to cancer. In this chapter we examine the recent literature on the mitochondrial dynamics-function relationship, and explore how it impacts on the development and progression of human diseases. We will also highlight the implications of therapeutic manipulation of mitochondrial dynamics in treating various human pathologies.
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215
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Flicker-assisted localization microscopy reveals altered mitochondrial architecture in hypertension. Sci Rep 2015; 5:16875. [PMID: 26593883 PMCID: PMC4655370 DOI: 10.1038/srep16875] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 10/21/2015] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial morphology is central to normal physiology and disease development. However, in many live cells and tissues, complex mitochondrial structures exist and morphology has been difficult to quantify. We have measured the shape of electrically-discrete mitochondria, imaging them individually to restore detail hidden in clusters and demarcate functional boundaries. Stochastic “flickers” of mitochondrial membrane potential were visualized with a rapidly-partitioning fluorophore and the pixel-by-pixel covariance of spatio-temporal fluorescence changes analyzed. This Flicker-assisted Localization Microscopy (FaLM) requires only an epifluorescence microscope and sensitive camera. In vascular myocytes, the apparent variation in mitochondrial size was partly explained by densely-packed small mitochondria. In normotensive animals, mitochondria were small spheres or rods. In hypertension, mitochondria were larger, occupied more of the cell volume and were more densely clustered. FaLM provides a convenient tool for increased discrimination of mitochondrial architecture and has revealed mitochondrial alterations that may contribute to hypertension.
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Ferdinandy P, Hausenloy DJ, Heusch G, Baxter GF, Schulz R. Interaction of risk factors, comorbidities, and comedications with ischemia/reperfusion injury and cardioprotection by preconditioning, postconditioning, and remote conditioning. Pharmacol Rev 2015; 66:1142-74. [PMID: 25261534 DOI: 10.1124/pr.113.008300] [Citation(s) in RCA: 461] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Pre-, post-, and remote conditioning of the myocardium are well described adaptive responses that markedly enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and provide therapeutic paradigms for cardioprotection. Nevertheless, more than 25 years after the discovery of ischemic preconditioning, we still do not have established cardioprotective drugs on the market. Most experimental studies on cardioprotection are still undertaken in animal models, in which ischemia/reperfusion is imposed in the absence of cardiovascular risk factors. However, ischemic heart disease in humans is a complex disorder caused by, or associated with, cardiovascular risk factors and comorbidities, including hypertension, hyperlipidemia, diabetes, insulin resistance, heart failure, altered coronary circulation, and aging. These risk factors induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury per se and responses to cardioprotective interventions. Moreover, some of the medications used to treat these risk factors, including statins, nitrates, and antidiabetic drugs, may impact cardioprotection by modifying cellular signaling. The aim of this article is to review the recent evidence that cardiovascular risk factors and their medication may modify the response to cardioprotective interventions. We emphasize the critical need to take into account the presence of cardiovascular risk factors and concomitant medications when designing preclinical studies for the identification and validation of cardioprotective drug targets and clinical studies. This will hopefully maximize the success rate of developing rational approaches to effective cardioprotective therapies for the majority of patients with multiple risk factors.
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Affiliation(s)
- Péter Ferdinandy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged and Pharmahungary Group, Szeged, Hungary (P.F.); The Hatter Cardiovascular Institute, University College London, London, United Kingdom (D.J.H.); Institute for Pathophysiology, University of Essen Medical School, Essen, Germany (G.H.); Division of Pharmacology, Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom (G.F.B.); and Institute of Physiology, Justus-Liebig University, Giessen, Germany (R.S.)
| | - Derek J Hausenloy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged and Pharmahungary Group, Szeged, Hungary (P.F.); The Hatter Cardiovascular Institute, University College London, London, United Kingdom (D.J.H.); Institute for Pathophysiology, University of Essen Medical School, Essen, Germany (G.H.); Division of Pharmacology, Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom (G.F.B.); and Institute of Physiology, Justus-Liebig University, Giessen, Germany (R.S.)
| | - Gerd Heusch
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged and Pharmahungary Group, Szeged, Hungary (P.F.); The Hatter Cardiovascular Institute, University College London, London, United Kingdom (D.J.H.); Institute for Pathophysiology, University of Essen Medical School, Essen, Germany (G.H.); Division of Pharmacology, Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom (G.F.B.); and Institute of Physiology, Justus-Liebig University, Giessen, Germany (R.S.)
| | - Gary F Baxter
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged and Pharmahungary Group, Szeged, Hungary (P.F.); The Hatter Cardiovascular Institute, University College London, London, United Kingdom (D.J.H.); Institute for Pathophysiology, University of Essen Medical School, Essen, Germany (G.H.); Division of Pharmacology, Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom (G.F.B.); and Institute of Physiology, Justus-Liebig University, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged and Pharmahungary Group, Szeged, Hungary (P.F.); The Hatter Cardiovascular Institute, University College London, London, United Kingdom (D.J.H.); Institute for Pathophysiology, University of Essen Medical School, Essen, Germany (G.H.); Division of Pharmacology, Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom (G.F.B.); and Institute of Physiology, Justus-Liebig University, Giessen, Germany (R.S.)
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217
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Ong SB, Kalkhoran SB, Cabrera-Fuentes HA, Hausenloy DJ. Mitochondrial fusion and fission proteins as novel therapeutic targets for treating cardiovascular disease. Eur J Pharmacol 2015; 763:104-14. [PMID: 25987420 PMCID: PMC4784719 DOI: 10.1016/j.ejphar.2015.04.056] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 03/28/2015] [Accepted: 04/09/2015] [Indexed: 12/11/2022]
Abstract
The past decade has witnessed a number of exciting developments in the field of mitochondrial dynamics - a phenomenon in which changes in mitochondrial shape and movement impact on cellular physiology and pathology. By undergoing fusion and fission, mitochondria are able to change their morphology between elongated interconnected networks and discrete fragmented structures, respectively. The cardiac mitochondria, in particular, have garnered much interest due to their unique spatial arrangement in the adult cardiomyocyte, and the multiple roles they play in cell death and survival. In this article, we review the role of the mitochondrial fusion and fission proteins as novel therapeutic targets for treating cardiovascular disease.
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Affiliation(s)
- Sang-Bing Ong
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore; National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore; Department of Clinical Sciences, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia
| | | | - Hector A Cabrera-Fuentes
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore; National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore; Institute of Biochemistry, Medical School, Justus-Liebig University, Giessen, Germany; Department of Microbiology, Kazan Federal University, Kazan, Russian Federation
| | - Derek J Hausenloy
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore; National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore; The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, University College London, UK; The National Institute of Health Research University College London Hospitals Biomedical Research Centre, UK.
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218
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Cahill TJ, Leo V, Kelly M, Stockenhuber A, Kennedy NW, Bao L, Cereghetti GM, Harper AR, Czibik G, Liao C, Bellahcene M, Steeples V, Ghaffari S, Yavari A, Mayer A, Poulton J, Ferguson DJP, Scorrano L, Hettiarachchi NT, Peers C, Boyle J, Hill RB, Simmons A, Watkins H, Dear TN, Ashrafian H. Resistance of Dynamin-related Protein 1 Oligomers to Disassembly Impairs Mitophagy, Resulting in Myocardial Inflammation and Heart Failure. J Biol Chem 2015; 290:25907-19. [PMID: 26370078 DOI: 10.1074/jbc.m115.665695] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Indexed: 11/06/2022] Open
Abstract
We have reported previously that a missense mutation in the mitochondrial fission gene Dynamin-related protein 1 (Drp1) underlies the Python mouse model of monogenic dilated cardiomyopathy. The aim of this study was to investigate the consequences of the C452F mutation on Drp1 protein function and to define the cellular sequelae leading to heart failure in the Python monogenic dilated cardiomyopathy model. We found that the C452F mutation increased Drp1 GTPase activity. The mutation also conferred resistance to oligomer disassembly by guanine nucleotides and high ionic strength solutions. In a mouse embryonic fibroblast model, Drp1 C452F cells exhibited abnormal mitochondrial morphology and defective mitophagy. Mitochondria in C452F mouse embryonic fibroblasts were depolarized and had reduced calcium uptake with impaired ATP production by oxidative phosphorylation. In the Python heart, we found a corresponding progressive decline in oxidative phosphorylation with age and activation of sterile inflammation. As a corollary, enhancing autophagy by exposure to a prolonged low-protein diet improved cardiac function in Python mice. In conclusion, failure of Drp1 disassembly impairs mitophagy, leading to a downstream cascade of mitochondrial depolarization, aberrant calcium handling, impaired ATP synthesis, and activation of sterile myocardial inflammation, resulting in heart failure.
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Affiliation(s)
| | - Vincenzo Leo
- the Leeds Institute of Molecular Medicine, Wellcome Trust Brenner Building, St. James's University Hospital, Leeds LS9 7TF, United Kingdom
| | | | | | - Nolan W Kennedy
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Leyuan Bao
- Weatherall Institute of Molecular Medicine, Nuffield Department of Medicine, and
| | - Grazia M Cereghetti
- the Department of Cell Physiology and Metabolism, University of Geneva, Geneva, CH-1211, Switzerland, and
| | | | | | - Chunyan Liao
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | | | | | | | | | - Alice Mayer
- Weatherall Institute of Molecular Medicine, Nuffield Department of Medicine, and
| | - Joanna Poulton
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | | | - Luca Scorrano
- the Department of Cell Physiology and Metabolism, University of Geneva, Geneva, CH-1211, Switzerland, and
| | - Nishani T Hettiarachchi
- the Division of Cardiovascular and Diabetes Research, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Chris Peers
- the Division of Cardiovascular and Diabetes Research, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - John Boyle
- the Division of Cardiovascular and Diabetes Research, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - R Blake Hill
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alison Simmons
- Weatherall Institute of Molecular Medicine, Nuffield Department of Medicine, and
| | | | - T Neil Dear
- the Leeds Institute of Molecular Medicine, Wellcome Trust Brenner Building, St. James's University Hospital, Leeds LS9 7TF, United Kingdom
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219
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Caino MC, Altieri DC. Disabling mitochondrial reprogramming in cancer. Pharmacol Res 2015; 102:42-5. [PMID: 26365877 DOI: 10.1016/j.phrs.2015.08.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 08/30/2015] [Indexed: 10/23/2022]
Abstract
Recent studies have demonstrated that tumor cells exposed to molecular therapy with PI3K antagonists redistribute their mitochondria to the peripheral cytoskeleton, fueling membrane dynamics, turnover of focal adhesion complexes and increased tumor cell motility and invasion. Although this process paradoxically increases metastatic propensity during molecular therapy, it also emphasizes a critical role of regional mitochondrial bioenergetics in tumor metabolic reprogramming and may offer prime therapeutic opportunities to prevent disseminated disease.
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Affiliation(s)
- M Cecilia Caino
- Prostate Cancer Discovery and Development Program, Tumor Microenvironment and Metastasis Program, The Wistar Institute, Philadelphia, PA 19104, United States
| | - Dario C Altieri
- Prostate Cancer Discovery and Development Program, Tumor Microenvironment and Metastasis Program, The Wistar Institute, Philadelphia, PA 19104, United States.
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220
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Kornfeld OS, Hwang S, Disatnik MH, Chen CH, Qvit N, Mochly-Rosen D. Mitochondrial reactive oxygen species at the heart of the matter: new therapeutic approaches for cardiovascular diseases. Circ Res 2015; 116:1783-99. [PMID: 25999419 DOI: 10.1161/circresaha.116.305432] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Reactive oxygen species (ROS) have been implicated in a variety of age-related diseases, including multiple cardiovascular disorders. However, translation of ROS scavengers (antioxidants) into the clinic has not been successful. These antioxidants grossly reduce total levels of cellular ROS including ROS that participate in physiological signaling. In this review, we challenge the traditional antioxidant therapeutic approach that targets ROS directly with novel approaches that improve mitochondrial functions to more effectively treat cardiovascular diseases.
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Affiliation(s)
- Opher S Kornfeld
- From the Department of Chemical and Systems Biology, Stanford University School of Medicine, CA
| | - Sunhee Hwang
- From the Department of Chemical and Systems Biology, Stanford University School of Medicine, CA
| | - Marie-Hélène Disatnik
- From the Department of Chemical and Systems Biology, Stanford University School of Medicine, CA
| | - Che-Hong Chen
- From the Department of Chemical and Systems Biology, Stanford University School of Medicine, CA
| | - Nir Qvit
- From the Department of Chemical and Systems Biology, Stanford University School of Medicine, CA
| | - Daria Mochly-Rosen
- From the Department of Chemical and Systems Biology, Stanford University School of Medicine, CA.
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221
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Abstract
Mitochondria are highly dynamic, except in adult cardiomyocytes. Yet, the fission and fusion-promoting proteins that mediate mitochondrial dynamism are highly expressed in, and essential to the normal functioning of, hearts. Here, we review accumulating evidence supporting important roles for mitochondrial fission and fusion in cardiac mitochondrial quality control, focusing on the PTEN-induced putative kinase 1-Parkin mitophagy pathway. Based in part on recent findings from in vivo mouse models in which mitofusin-mediated mitochondrial fusion or dynamin-related protein 1-mediated mitochondrial fission was conditionally interrupted in cardiac myocytes, we propose several new concepts that may provide insight into the cardiac mitochondrial dynamism-mitophagy interactome.
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Affiliation(s)
- Orian S Shirihai
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.)
| | - Moshi Song
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.)
| | - Gerald W Dorn
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.).
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222
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de Lima Portella R, Lynn Bickta J, Shiva S. Nitrite Confers Preconditioning and Cytoprotection After Ischemia/Reperfusion Injury Through the Modulation of Mitochondrial Function. Antioxid Redox Signal 2015; 23:307-27. [PMID: 26094636 DOI: 10.1089/ars.2015.6260] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE Nitrite is now recognized as an intrinsic signaling molecule that mediates a number of biological processes. One of the most reproducible effects of nitrite is its ability to mediate cytoprotection after ischemia/reperfusion (I/R). This robust phenomenon has been reproduced by a number of investigators in varying animal models focusing on different target organs. Furthermore, nitrite's cytoprotective versatility is highlighted by its ability to mediate delayed preconditioning and remote conditioning in addition to acute protection. RECENT ADVANCES In the last 10 years, significant progress has been made in elucidating the mechanisms underlying nitrite-mediated ischemic tolerance. CRITICAL ISSUES The mitochondrion, which is essential to both the progression of I/R injury and the protection afforded by preconditioning, has emerged as a major subcellular target for nitrite. This review will outline the role of the mitochondrion in I/R injury and preconditioning, review the accumulated preclinical studies demonstrating nitrite-mediated cytoprotection, and finally focus on the known interactions of nitrite with mitochondria and their role in the mechanism of nitrite-mediated ischemic tolerance. FUTURE DIRECTIONS These studies set the stage for current clinical trials testing the efficacy of nitrite to prevent warm and cold I/R injury.
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Affiliation(s)
- Rafael de Lima Portella
- 1 Vascular Medicine Institute, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania
| | - Janelle Lynn Bickta
- 1 Vascular Medicine Institute, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania.,2 Department of Bioengineering, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania
| | - Sruti Shiva
- 1 Vascular Medicine Institute, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania.,3 Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania.,4 Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania
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223
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Abstract
A large number of protein substrates are phosphorylated by each protein kinase under physiological and pathological conditions. However, it remains a challenge to determine which of these phosphorylated substrates of a given kinase is critical for each cellular response. Genetics enabled the generation of separation-of-function mutations that selectively cause a loss of one molecular event without affecting others, thus providing some tools to assess the importance of that one event for the measured physiological response. However, the genetic approach is laborious and not adaptable to all systems. Furthermore, pharmacological tools of the catalytic site are not optimal due to their non-selective nature. In the present brief review, we discuss some of the challenges in drug development that will regulate the multifunctional protein kinase Cδ (PKCδ).
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224
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Wang F, Yang J, Sun J, Dong Y, Zhao H, Shi H, Fu L. Testosterone replacement attenuates mitochondrial damage in a rat model of myocardial infarction. J Endocrinol 2015; 225:101-11. [PMID: 25770118 DOI: 10.1530/joe-14-0638] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/12/2015] [Indexed: 01/08/2023]
Abstract
Testosterone can affect cardiovascular disease, but its effects on mitochondrial dynamics in the post-infarct myocardium remain unclear. To observe the effects of testosterone replacement, a rat model of castration-myocardial infarction (MI) was established by ligating the left anterior descending coronary artery 2 weeks after castration with or without testosterone treatment. Expression of mitochondrial fission and fusion proteins was detected by western blot and immunofluorescence 14 days after MI. Cardiac function, myocardial inflammatory infiltration and fibrosis, cardiomyocyte apoptosis, mitochondrial microstructure, and ATP levels were also assessed. Compared with MI rats, castrated rats showed aggravated mitochondrial and myocardial insults, including mitochondrial swelling and disordered arrangement; loss of cristae, reduced mitochondrial length; decreased ATP levels; cardiomyocyte apoptosis; and impaired cardiac function. Results of western blotting analyses indicated that castration downregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1A) and mitofusin 2, but upregulated dynamin-related protein 1. The results were also supported by results obtained using immunofluorescence. However, these detrimental effects were reversed by testosterone supplementation, which also elevated the upstream AMP-activated protein kinase (AMPK) activation of PGC1A. Thus, testosterone can protect mitochondria in the post-infarct myocardium, partly via the AMPK-PGC1A pathway, thereby decreasing mitochondrial dysfunction and cardiomyocyte apoptosis. The effects of testosterone were confirmed by the results of ELISA analyses.
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Affiliation(s)
- Fengyue Wang
- Laboratory of Cardiovascular Internal Medicine Department First Affiliated Hospital, Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, China Laboratory of Cardiovascular Internal Medicine Department The Heilongjiang Province Hospital, 82 Zhongshan Lu, Xiangfang District, Harbin, Heilongjiang 150001, China
| | - Jing Yang
- Laboratory of Cardiovascular Internal Medicine Department First Affiliated Hospital, Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, China Laboratory of Cardiovascular Internal Medicine Department The Heilongjiang Province Hospital, 82 Zhongshan Lu, Xiangfang District, Harbin, Heilongjiang 150001, China
| | - Junfeng Sun
- Laboratory of Cardiovascular Internal Medicine Department First Affiliated Hospital, Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, China Laboratory of Cardiovascular Internal Medicine Department The Heilongjiang Province Hospital, 82 Zhongshan Lu, Xiangfang District, Harbin, Heilongjiang 150001, China
| | - Yanli Dong
- Laboratory of Cardiovascular Internal Medicine Department First Affiliated Hospital, Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, China Laboratory of Cardiovascular Internal Medicine Department The Heilongjiang Province Hospital, 82 Zhongshan Lu, Xiangfang District, Harbin, Heilongjiang 150001, China
| | - Hong Zhao
- Laboratory of Cardiovascular Internal Medicine Department First Affiliated Hospital, Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, China Laboratory of Cardiovascular Internal Medicine Department The Heilongjiang Province Hospital, 82 Zhongshan Lu, Xiangfang District, Harbin, Heilongjiang 150001, China
| | - Hui Shi
- Laboratory of Cardiovascular Internal Medicine Department First Affiliated Hospital, Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, China Laboratory of Cardiovascular Internal Medicine Department The Heilongjiang Province Hospital, 82 Zhongshan Lu, Xiangfang District, Harbin, Heilongjiang 150001, China
| | - Lu Fu
- Laboratory of Cardiovascular Internal Medicine Department First Affiliated Hospital, Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, China Laboratory of Cardiovascular Internal Medicine Department The Heilongjiang Province Hospital, 82 Zhongshan Lu, Xiangfang District, Harbin, Heilongjiang 150001, China
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225
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Givvimani S, Pushpakumar SB, Metreveli N, Veeranki S, Kundu S, Tyagi SC. Role of mitochondrial fission and fusion in cardiomyocyte contractility. Int J Cardiol 2015; 187:325-33. [PMID: 25841124 DOI: 10.1016/j.ijcard.2015.03.352] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/12/2015] [Accepted: 03/22/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Mitochondria constitute 30% of cell volume and are engaged in two dynamic processes called fission and fusion, regulated by Drp-1 (dynamin related protein) and mitofusin 2 (Mfn2). Previously, we showed that Drp-1 inhibition attenuates cardiovascular dysfunction following pressure overload in aortic banding model and myocardial infarction. As dynamic organelles, mitochondria are capable of changing their morphology in response to stress. However, whether such changes can alter their function and in turn cellular function is unknown. Further, a direct role of fission and fusion in cardiomyocyte contractility has not yet been studied. In this study, we hypothesize that disrupted fission and fusion balance by increased Drp-1 and decreased Mfn2 expression in cardiomyocytes affects their contractility through alterations in the calcium and potassium concentrations. METHODS To verify this, we used freshly isolated ventricular myocytes from wild type mouse and transfected them with either siRNA to Drp-1 or Mfn2. Myocyte contractility studies were performed by IonOptix using a myopacer. Intracellular calcium and potassium measurements were done using flow cytometry. Immunocytochemistry (ICC) was done to evaluate live cell mitochondria and its membrane potential. Protein expression was done by western blot and immunocytochemistry. RESULTS We found that silencing mitochondrial fission increased the myocyte contractility, while fusion inhibition decreased contractility with simultaneous changes in calcium and potassium. Also, we observed that increase in fission prompted decrease in Serca-2a and increase in cytochrome c leakage leading to mitophagy. CONCLUSION Our results suggested that regulating mitochondrial fission and fusion have direct effects on overall cardiomyocyte contractility and thus function.
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Affiliation(s)
- S Givvimani
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, United States.
| | - S B Pushpakumar
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, United States
| | - N Metreveli
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, United States
| | - S Veeranki
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, United States
| | - S Kundu
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, United States
| | - S C Tyagi
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, United States
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226
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Inhibition of the mitochondrial fission protein dynamin-related protein 1 improves survival in a murine cardiac arrest model. Crit Care Med 2015; 43:e38-47. [PMID: 25599491 DOI: 10.1097/ccm.0000000000000817] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES Survival following sudden cardiac arrest is poor despite advances in cardiopulmonary resuscitation and the use of therapeutic hypothermia. Dynamin-related protein 1, a regulator of mitochondrial fission, is an important determinant of reactive oxygen species generation, myocardial necrosis, and left ventricular function following ischemia/reperfusion injury, but its role in cardiac arrest is unknown. We hypothesized that dynamin-related protein 1 inhibition would improve survival, cardiac hemodynamics, and mitochondrial function in an in vivo model of cardiac arrest. DESIGN Laboratory investigation. SETTING University laboratory. INTERVENTIONS Anesthetized and ventilated adult female C57BL/6 wild-type mice underwent an 8-minute KCl-induced cardiac arrest followed by 90 seconds of cardiopulmonary resuscitation. Mice were then blindly randomized to a single IV injection of Mdivi-1 (0.24 mg/kg), a small molecule dynamin-related protein 1 inhibitor or vehicle (dimethyl sulfoxide). MEASUREMENTS AND MAIN RESULTS Following resuscitation from cardiac arrest, mitochondrial fission was evidenced by dynamin-related protein 1 translocation to the mitochondrial membrane and a decrease in mitochondrial size. Mitochondrial fission was associated with increased lactate and evidence of oxidative damage. Mdivi-1 administration during cardiopulmonary resuscitation inhibited dynamin-related protein 1 activation, preserved mitochondrial morphology, and decreased oxidative damage. Mdivi-1 also reduced the time to return of spontaneous circulation (116 ± 4 vs 143 ± 7 s; p < 0.001) during cardiopulmonary resuscitation and enhanced myocardial performance post-return of spontaneous circulation. These improvements were associated with significant increases in survival (65% vs 33%) and improved neurological scores up to 72 hours post cardiac arrest. CONCLUSIONS Post-cardiac arrest inhibition of dynamin-related protein 1 improves time to return of spontaneous circulation and myocardial hemodynamics, resulting in improved survival and neurological outcomes in a murine model of cardiac arrest. Pharmacological targeting of mitochondrial fission may be a promising therapy for cardiac arrest.
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227
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Affiliation(s)
- Gerald W Dorn
- From the Department of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO.
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228
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Sharp WW. Dynamin-related protein 1 as a therapeutic target in cardiac arrest. J Mol Med (Berl) 2015; 93:243-52. [PMID: 25659608 DOI: 10.1007/s00109-015-1257-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/13/2015] [Accepted: 01/26/2015] [Indexed: 12/23/2022]
Abstract
Despite improvements in cardiopulmonary resuscitation (CPR) quality, defibrillation technologies, and implementation of therapeutic hypothermia, less than 10 % of out-of-hospital cardiac arrest (OHCA) victims survive to hospital discharge. New resuscitation therapies have been slow to develop, in part, because the pathophysiologic mechanisms critical for resuscitation are not understood. During cardiac arrest, systemic cessation of blood flow results in whole body ischemia. CPR and the restoration of spontaneous circulation (ROSC), both result in immediate reperfusion injury of the heart that is characterized by severe contractile dysfunction. Unlike diseases of localized ischemia/reperfusion (IR) injury (myocardial infarction and stroke), global IR injury of organs results in profound organ dysfunction with far shorter ischemic times. The two most commonly injured organs following cardiac arrest resuscitation, the heart and brain, are critically dependent on mitochondrial function. New insights into mitochondrial dynamics and the role of the mitochondrial fission protein Dynamin-related protein 1 (Drp1) in apoptosis have made targeting these mechanisms attractive for IR therapy. In animal models, inhibiting Drp1 following IR injury or cardiac arrest confers protection to both the heart and brain. In this review, the relationship of the major mitochondrial fission protein Drp1 to ischemic changes in the heart and its targeting as a new therapeutic target following cardiac arrest are discussed.
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Affiliation(s)
- Willard W Sharp
- Section of Emergency Medicine, Department of Medicine, University of Chicago, 5841 S. Maryland Ave, MC 5068, Chicago, IL, 60637, USA,
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229
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Disatnik MH, Hwang S, Ferreira JCB, Mochly-Rosen D. New therapeutics to modulate mitochondrial dynamics and mitophagy in cardiac diseases. J Mol Med (Berl) 2015; 93:279-87. [PMID: 25652199 PMCID: PMC4333238 DOI: 10.1007/s00109-015-1256-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/13/2015] [Accepted: 01/23/2015] [Indexed: 12/20/2022]
Abstract
The processes that control the number and shape of the mitochondria (mitochondrial dynamics) and the removal of damaged mitochondria (mitophagy) have been the subject of intense research. Recent work indicates that these processes may contribute to the pathology associated with cardiac diseases. This review describes some of the key proteins that regulate these processes and their potential as therapeutic targets for cardiac diseases.
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Affiliation(s)
- Marie-Hélène Disatnik
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
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230
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Abstract
Mitochondrial fitness is central to heart health. In many cell types, mitochondria are dynamic, interconnected filamentous networks. By comparison, mitochondria of healthy postmitotic adult cardiomyocytes are shortened, round, hypodynamic organelles. Mitochondrial networks are absent in cardiomyocytes; fission, fusion, and organelle mobility are not normally observed. Nevertheless, mitochondrial fission factor Drp1 and fusion factors Mfn1, Mfn2, and Opa1 are abundant and indispensable in adult hearts. Here, we review recent insights into roles for mitochondrial dynamics factors not strictly related to morphometric remodeling, advancing the argument that fission and fusion of cardiomyocyte mitochondria support surveillance, sequestration, and mitophagic removal of damaged organelles.
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Affiliation(s)
- Moshi Song
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63108, USA
| | - Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63108, USA.
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231
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Song M, Mihara K, Chen Y, Scorrano L, Dorn GW. Mitochondrial fission and fusion factors reciprocally orchestrate mitophagic culling in mouse hearts and cultured fibroblasts. Cell Metab 2015; 21:273-286. [PMID: 25600785 PMCID: PMC4318753 DOI: 10.1016/j.cmet.2014.12.011] [Citation(s) in RCA: 350] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/14/2014] [Accepted: 12/13/2014] [Indexed: 12/18/2022]
Abstract
How mitochondrial dynamism (fission and fusion) affects mitochondrial quality control is unclear. We uncovered distinct effects on mitophagy of inhibiting Drp1-mediated mitochondrial fission versus mitofusin-mediated mitochondrial fusion. Conditional cardiomyocyte-specific Drp1 ablation evoked mitochondrial enlargement, lethal dilated cardiomyopathy, and cardiomyocyte necrosis. Conditionally ablating cardiomyocyte mitofusins (Mfn) caused mitochondrial fragmentation with eccentric remodeling and no cardiomyocyte dropout. Parallel studies in cultured murine embryonic fibroblasts (MEFs) and in vivo mouse hearts revealed that Mfn1/Mfn2 deletion provoked accumulation of defective mitochondria exhibiting an unfolded protein response, without appropriately increasing mitophagy. Conversely, interrupting mitochondrial fission by Drp1 ablation increased mitophagy and caused a generalized loss of mitochondria. Mitochondrial permeability transition pore (MPTP) opening in Drp1 null mitochondria was associated with mitophagy in MEFs and contributed to cardiomyocyte necrosis and dilated cardiomyopathy in mice. Drp1, MPTP, and cardiomyocyte mitophagy are functionally integrated. Mitochondrial fission and fusion have opposing roles during in vivo cardiac mitochondrial quality control.
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Affiliation(s)
- Moshi Song
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Katsuyoshi Mihara
- Department of Molecular Biology, Kyushu University, Fukuoka 812-8582, Japan
| | - Yun Chen
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Luca Scorrano
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine and Department of Biology, University of Padua, Padova 35129, Italy
| | - Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
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232
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Ikeda Y, Shirakabe A, Brady C, Zablocki D, Ohishi M, Sadoshima J. Molecular mechanisms mediating mitochondrial dynamics and mitophagy and their functional roles in the cardiovascular system. J Mol Cell Cardiol 2015; 78:116-22. [PMID: 25305175 PMCID: PMC4268018 DOI: 10.1016/j.yjmcc.2014.09.019] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/12/2014] [Accepted: 09/16/2014] [Indexed: 02/05/2023]
Abstract
Mitochondria are essential organelles that produce the cellular energy source, ATP. Dysfunctional mitochondria are involved in the pathophysiology of heart disease, which is associated with reduced levels of ATP and excessive production of reactive oxygen species. Mitochondria are dynamic organelles that change their morphology through fission and fusion in order to maintain their function. Fusion connects neighboring depolarized mitochondria and mixes their contents to maintain membrane potential. In contrast, fission segregates damaged mitochondria from intact ones, where the damaged part of mitochondria is subjected to mitophagy whereas the intact part to fusion. It is generally believed that mitochondrial fusion is beneficial for the heart, especially under stress conditions, because it consolidates the mitochondria's ability to supply energy. However, both excessive fusion and insufficient fission disrupt the mitochondrial quality control mechanism and potentiate cell death. In this review, we discuss the role of mitochondrial dynamics and mitophagy in the heart and the cardiomyocytes therein, with a focus on their roles in cardiovascular disease. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".
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Affiliation(s)
- Yoshiyuki Ikeda
- Department of Cell Biology & Molecular Medicine, NJ Medical School, Rutgers University, USA; Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Japan
| | - Akihiro Shirakabe
- Department of Cell Biology & Molecular Medicine, NJ Medical School, Rutgers University, USA
| | - Christopher Brady
- Department of Cell Biology & Molecular Medicine, NJ Medical School, Rutgers University, USA
| | - Daniela Zablocki
- Department of Cell Biology & Molecular Medicine, NJ Medical School, Rutgers University, USA
| | - Mitsuru Ohishi
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Japan
| | - Junichi Sadoshima
- Department of Cell Biology & Molecular Medicine, NJ Medical School, Rutgers University, USA.
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233
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Hall AR, Burke N, Dongworth RK, Hausenloy DJ. Mitochondrial fusion and fission proteins: novel therapeutic targets for combating cardiovascular disease. Br J Pharmacol 2014; 171:1890-906. [PMID: 24328763 PMCID: PMC3976611 DOI: 10.1111/bph.12516] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/21/2013] [Accepted: 10/28/2013] [Indexed: 12/18/2022] Open
Abstract
Mitochondria are no longer considered to be solely the static powerhouses of the cell. While they are undoubtedly essential to sustaining life and meeting the energy requirements of the cell through oxidative phosphorylation, they are now regarded as highly dynamic organelles with multiple functions, playing key roles in cell survival and death. In this review, we discuss the emerging role of mitochondrial fusion and fission proteins, as novel therapeutic targets for treating a wide range of cardiovascular diseases.
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Affiliation(s)
- A R Hall
- The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, NIHR University College London Hospitals Biomedical Research Centre, University College London Hospital & Medical School, London, UK
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234
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Halestrap AP, Pereira GC, Pasdois P. The role of hexokinase in cardioprotection - mechanism and potential for translation. Br J Pharmacol 2014; 172:2085-100. [PMID: 25204670 PMCID: PMC4386983 DOI: 10.1111/bph.12899] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 08/21/2014] [Accepted: 08/28/2014] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial permeability transition pore (mPTP) opening plays a critical role in cardiac reperfusion injury and its prevention is cardioprotective. Tumour cell mitochondria usually have high levels of hexokinase isoform 2 (HK2) bound to their outer mitochondrial membranes (OMM) and HK2 binding to heart mitochondria has also been implicated in resistance to reperfusion injury. HK2 dissociates from heart mitochondria during ischaemia, and the extent of this correlates with the infarct size on reperfusion. Here we review the mechanisms and regulations of HK2 binding to mitochondria and how this inhibits mPTP opening and consequent reperfusion injury. Major determinants of HK2 dissociation are the elevated glucose‐6‐phosphate concentrations and decreased pH in ischaemia. These are modulated by the myriad of signalling pathways implicated in preconditioning protocols as a result of a decrease in pre‐ischaemic glycogen content. Loss of mitochondrial HK2 during ischaemia is associated with permeabilization of the OMM to cytochrome c, which leads to greater reactive oxygen species production and mPTP opening during reperfusion. Potential interactions between HK2 and OMM proteins associated with mitochondrial fission (e.g. Drp1) and apoptosis (B‐cell lymphoma 2 family members) in these processes are examined. Also considered is the role of HK2 binding in stabilizing contact sites between the OMM and the inner membrane. Breakage of these during ischaemia is proposed to facilitate cytochrome c loss during ischaemia while increasing mPTP opening and compromising cellular bioenergetics during reperfusion. We end by highlighting the many unanswered questions and discussing the potential of modulating mitochondrial HK2 binding as a pharmacological target. Linked Articles This article is part of a themed section on Conditioning the Heart – Pathways to Translation. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue‐8
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Affiliation(s)
- Andrew P Halestrap
- School of Biochemistry and Bristol CardioVascular, University of Bristol, Bristol, UK
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235
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Gomes KMS, Bechara LRG, Lima VM, Ribeiro MAC, Campos JC, Dourado PM, Kowaltowski AJ, Mochly-Rosen D, Ferreira JCB. Aldehydic load and aldehyde dehydrogenase 2 profile during the progression of post-myocardial infarction cardiomyopathy: benefits of Alda-1. Int J Cardiol 2014; 179:129-38. [PMID: 25464432 DOI: 10.1016/j.ijcard.2014.10.140] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/25/2014] [Accepted: 10/18/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND/OBJECTIVES We previously demonstrated that reducing cardiac aldehydic load by aldehyde dehydrogenase 2 (ALDH2), a mitochondrial enzyme responsible for metabolizing the major lipid peroxidation product, protects against acute ischemia/reperfusion injury and chronic heart failure. However, time-dependent changes in ALDH2 profile, aldehydic load and mitochondrial bioenergetics during progression of post-myocardial infarction (post-MI) cardiomyopathy are unknown and should be established to determine the optimal time window for drug treatment. METHODS Here we characterized cardiac ALDH2 activity and expression, lipid peroxidation, 4-hydroxy-2-nonenal (4-HNE) adduct formation, glutathione pool and mitochondrial energy metabolism and H₂O₂ release during the 4 weeks after permanent left anterior descending (LAD) coronary artery occlusion in rats. RESULTS We observed a sustained disruption of cardiac mitochondrial function during the progression of post-MI cardiomyopathy, characterized by >50% reduced mitochondrial respiratory control ratios and up to 2 fold increase in H₂O₂ release. Mitochondrial dysfunction was accompanied by accumulation of cardiac and circulating lipid peroxides and 4-HNE protein adducts and down-regulation of electron transport chain complexes I and V. Moreover, increased aldehydic load was associated with a 90% reduction in cardiac ALDH2 activity and increased glutathione pool. Further supporting an ALDH2 mechanism, sustained Alda-1 treatment (starting 24h after permanent LAD occlusion surgery) prevented aldehydic overload, mitochondrial dysfunction and improved ventricular function in post-MI cardiomyopathy rats. CONCLUSION Taken together, our findings demonstrate a disrupted mitochondrial metabolism along with an insufficient cardiac ALDH2-mediated aldehyde clearance during the progression of ventricular dysfunction, suggesting a potential therapeutic value of ALDH2 activators during the progression of post-myocardial infarction cardiomyopathy.
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Affiliation(s)
- Katia M S Gomes
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | - Luiz R G Bechara
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | - Vanessa M Lima
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | - Márcio A C Ribeiro
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | - Juliane C Campos
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | | | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de Sao Paulo, Brazil
| | - Daria Mochly-Rosen
- Department of Chemical & Systems Biology, Stanford University School of Medicine, Stanford, USA
| | - Julio C B Ferreira
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Brazil.
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236
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Ikeda Y, Shirakabe A, Maejima Y, Zhai P, Sciarretta S, Toli J, Nomura M, Mihara K, Egashira K, Ohishi M, Abdellatif M, Sadoshima J. Endogenous Drp1 mediates mitochondrial autophagy and protects the heart against energy stress. Circ Res 2014; 116:264-78. [PMID: 25332205 DOI: 10.1161/circresaha.116.303356] [Citation(s) in RCA: 421] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
RATIONALE Both fusion and fission contribute to mitochondrial quality control. How unopposed fusion affects survival of cardiomyocytes and left ventricular function in the heart is poorly understood. OBJECTIVE We investigated the role of dynamin-related protein 1 (Drp1), a GTPase that mediates mitochondrial fission, in mediating mitochondrial autophagy, ventricular function, and stress resistance in the heart. METHODS AND RESULTS Drp1 downregulation induced mitochondrial elongation, accumulation of damaged mitochondria, and increased apoptosis in cardiomyocytes at baseline. Drp1 downregulation also suppressed autophagosome formation and autophagic flux at baseline and in response to glucose deprivation in cardiomyocytes. The lack of lysosomal translocation of mitochondrially targeted Keima indicates that Drp1 downregulation suppressed mitochondrial autophagy. Mitochondrial elongation and accumulation of damaged mitochondria were also observed in tamoxifen-inducible cardiac-specific Drp1 knockout mice. After Drp1 downregulation, cardiac-specific Drp1 knockout mice developed left ventricular dysfunction, preceded by mitochondrial dysfunction, and died within 13 weeks. Autophagic flux is significantly suppressed in cardiac-specific Drp1 knockout mice. Although left ventricular function in cardiac-specific Drp1 heterozygous knockout mice was normal at 12 weeks of age, left ventricular function decreased more severely after 48 hours of fasting, and the infarct size/area at risk after ischemia/reperfusion was significantly greater in cardiac-specific Drp1 heterozygous knockout than in control mice. CONCLUSIONS Disruption of Drp1 induces mitochondrial elongation, inhibits mitochondrial autophagy, and causes mitochondrial dysfunction, thereby promoting cardiac dysfunction and increased susceptibility to ischemia/reperfusion.
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Affiliation(s)
- Yoshiyuki Ikeda
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Akihiro Shirakabe
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Yasuhiro Maejima
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Peiyong Zhai
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Sebastiano Sciarretta
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Jessica Toli
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Masatoshi Nomura
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Katsuyoshi Mihara
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Kensuke Egashira
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Mitsuru Ohishi
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Maha Abdellatif
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.)
| | - Junichi Sadoshima
- From the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark (Y.I., A.S., Y.M., P.Z., S.S., J.T., M.A., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S.); Department of Medicine and Bioregulatory Science (M.N.), Department of Molecular Biology (K.M.), Department of Cardiovascular Medicine, Department of Cardiovascular Research, Development, and Translational Medicine (K.E.), Graduate School of Medical Science, Kyushu University Hospital, Fukuoka, Japan; and Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan (M.O.).
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237
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Dorn GW, Kitsis RN. The mitochondrial dynamism-mitophagy-cell death interactome: multiple roles performed by members of a mitochondrial molecular ensemble. Circ Res 2014; 116:167-82. [PMID: 25323859 DOI: 10.1161/circresaha.116.303554] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mitochondrial research is experiencing a renaissance, in part, because of the recognition that these endosymbiotic descendants of primordial protobacteria seem to be pursuing their own biological agendas. Not only is mitochondrial metabolism required to produce most of the biochemical energy that supports their eukaryotic hosts (us) but mitochondria can actively (through apoptosis and programmed necrosis) or passively (through reactive oxygen species toxicity) drive cellular dysfunction or demise. The cellular mitochondrial collective autoregulates its population through biogenic renewal and mitophagic culling; mitochondrial fission and fusion, 2 components of mitochondrial dynamism, are increasingly recognized as playing central roles as orchestrators of these processes. Mitochondrial dynamism is rare in striated muscle cells, so cardiac-specific genetic manipulation of mitochondrial fission and fusion factors has proven useful for revealing noncanonical functions of mitochondrial dynamics proteins. Here, we review newly described functions of mitochondrial fusion/fission proteins in cardiac mitochondrial quality control, cell death, calcium signaling, and cardiac development. A mechanistic conceptual paradigm is proposed in which cell death and selective organelle culling are not distinct processes, but are components of a unified and integrated quality control mechanism that exerts different effects when invoked to different degrees, depending on pathophysiological context. This offers a plausible explanation for seemingly paradoxical expression of mitochondrial dynamics and death factors in cardiomyocytes wherein mitochondrial morphometric remodeling does not normally occur and the ability to recover from cell suicide is severely limited.
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Affiliation(s)
- Gerald W Dorn
- From the Department of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (G.W.D.); and Departments of Medicine (Cardiology) and Cell Biology and Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY (R.N.K.).
| | - Richard N Kitsis
- From the Department of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (G.W.D.); and Departments of Medicine (Cardiology) and Cell Biology and Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY (R.N.K.)
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238
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Mao C, Zhang J, Lin S, Jing L, Xiang J, Wang M, Wang B, Xu P, Liu W, Song X, Lv C. MiRNA-30a inhibits AECs-II apoptosis by blocking mitochondrial fission dependent on Drp-1. J Cell Mol Med 2014; 18:2404-16. [PMID: 25284615 PMCID: PMC4302646 DOI: 10.1111/jcmm.12420] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/09/2014] [Indexed: 12/27/2022] Open
Abstract
Apoptosis of type II alveolar epithelial cells (AECs-II) is a key determinant of initiation and progression of lung fibrosis. However, the mechanism of miR-30a participation in the regulation of AECs-II apoptosis is ambiguous. In this study, we investigated whether miR-30a could block AECs-II apoptosis by repressing mitochondrial fission dependent on dynamin-related protein-1 (Drp-1). The levels of miR-30a in vivo and in vitro were determined through quantitative real-time PCR (qRT-PCR). The inhibition of miR-30a in AECs-II apoptosis, mitochondrial fission and its dependence on Drp-1, and Drp-1 expression and translocation were detected using miR-30a mimic, inhibitor-transfection method (gain- and loss-of-function), or Drp-1 siRNA technology. Results showed that miR-30a decreased in lung fibrosis. Gain- and loss-of-function studies revealed that the up-regulation of miR-30a could decrease AECs-II apoptosis, inhibit mitochondrial fission, and reduce Drp-1 expression and translocation. MiR-30a mimic/inhibitor and Drp-1 siRNA co-transfection showed that miR-30a could inhibit the mitochondrial fission dependent on Drp-1. This study demonstrated that miR-30a inhibited AECs-II apoptosis by repressing the mitochondrial fission dependent on Drp-1, and could function as a novel therapeutic target for lung fibrosis.
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Affiliation(s)
- Cuiping Mao
- Molecular Medicine Research Center, Binzhou Medical University, Yantai, China
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239
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Ong SB, Hall AR, Dongworth RK, Kalkhoran S, Pyakurel A, Scorrano L, Hausenloy DJ. Akt protects the heart against ischaemia-reperfusion injury by modulating mitochondrial morphology. Thromb Haemost 2014; 113:513-21. [PMID: 25253080 DOI: 10.1160/th14-07-0592] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 08/15/2014] [Indexed: 11/05/2022]
Abstract
The mechanism through which the protein kinase Akt (also called PKB), protects the heart against acute ischaemia-reperfusion injury (IRI) is not clear. Here, we investigate whether Akt mediates its cardioprotective effect by modulating mitochondrial morphology. Transfection of HL-1 cardiac cells with constitutively active Akt (caAkt) changed mitochondrial morphology as evidenced by an increase in the proportion of cells displaying predominantly elongated mitochondria (73 ± 5.0 % caAkt vs 49 ± 5.8 % control: N=80 cells/group; p< 0.05). This effect was associated with delayed time taken to induce mitochondrial permeability transition pore (MPTP) opening (by 2.4 ± 0.5 fold; N=80 cells/group: p< 0.05); and reduced cell death following simulated IRI (32.8 ± 1.2 % caAkt vs 63.8 ± 5.6 % control: N=320 cells/group: p< 0.05). Similar effects on mitochondrial morphology, MPTP opening, and cell survival post-IRI, were demonstrated with pharmacological activation of Akt using the known cardioprotective cytokine, erythropoietin (EPO). The effect of Akt on inducing mitochondrial elongation was found to be dependent on the mitochondrial fusion protein, Mitofusin-1 (Mfn1), as ablation of Mfn1 in mouse embryonic fibroblasts (MEFs) abrogated Akt-mediated mitochondrial elongation. Finally, in vivo pre-treatment with EPO reduced myocardial infarct size (as a % of the area at risk) in adult mice subjected to IRI (26.2 ± 2.6 % with EPO vs 46.1 ± 6.5 % in control; N=7/group: p< 0.05), and reduced the proportion of cells displaying myofibrillar disarray and mitochondrial fragmentation observed by electron microscopy in adult murine hearts subjected to ischaemia from 5.8 ± 1.0 % to 2.2 ± 1.0 % (N=5 hearts/group; p< 0.05). In conclusion, we found that either genetic or pharmacological activation of Akt protected the heart against acute ischaemia-reperfusion injury by modulating mitochondrial morphology.
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Affiliation(s)
| | | | | | | | | | | | - Derek J Hausenloy
- Dr. Derek J. Hausenloy, The Hatter Cardiovascular Institute, University College London Hospital, 67 Chenies Mews, London, WC1E 6HX, UK, Tel.: +44 203 447 9894, Fax: +44 203 447 9505, E-mail:
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240
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Givvimani S, Pushpakumar S, Veeranki S, Tyagi SC. Dysregulation of Mfn2 and Drp-1 proteins in heart failure. Can J Physiol Pharmacol 2014; 92:583-91. [PMID: 24905188 DOI: 10.1139/cjpp-2014-0060] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Therapeutic approaches for cardiac regenerative mechanisms have been explored over the past decade to target various cardiovascular diseases (CVD). Structural and functional aberrations of mitochondria have been observed in CVD. The significance of mitochondrial maturation and function in cardiomyocytes is distinguished by their attribution to embryonic stem cell differentiation into adult cardiomyocytes. An abnormal fission process has been implicated in heart failure, and treatment with mitochondrial division inhibitor 1 (Mdivi-1), a specific inhibitor of dynamin related protein-1 (Drp-1), has been shown to improve cardiac function. We recently observed that the ratio of mitofusin 2 (Mfn2; a fusion protein) and Drp-1 (a fission protein) was decreased during heart failure, suggesting increased mitophagy. Treatment with Mdivi-1 improved cardiac function by normalizing this ratio. Aberrant mitophagy and enhanced oxidative stress in the mitochondria contribute to abnormal activation of MMP-9, leading to degradation of the important gap junction protein connexin-43 (Cx-43) in the ventricular myocardium. Reduced Cx-43 levels were associated with increased fibrosis and ventricular dysfunction in heart failure. Treatment with Mdivi-1 restored MMP-9 and Cx-43 expression towards normal. In this review, we discuss mitochondrial dynamics, its relation to MMP-9 and Cx-43, and the therapeutic role of fission inhibition in heart failure.
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Affiliation(s)
- Srikanth Givvimani
- Department of Physiology & Biophysics, School of Medicine, University of Louisville, KY 40202, USA
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241
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Abstract
Though the mitochondrion was initially identified as a key organelle essentially required for energy production and oxidative metabolism, there is considerable evidence that mitochondria are intimately involved in regulating vital cellular processes, such as programmed cell death, proliferation and autophagy. Discovery of mitochondrial "shaping proteins" (Dynamin-related protein (Drp), mitofusins (Mfn) etc.) has revealed that mitochondria are highly dynamic organelles continually changing morphology by fission and fusion processes. Several human pathologies, including cancer, Parkinson's disease, Alzheimer's disease and cardiovascular diseases, have been linked to abnormalities in proteins that govern mitochondrial fission or fusion respectively. Notably, in the context of the heart, defects in mitochondrial dynamics resulting in too many fused and/or fragmented mitochondria have been associated with impaired cardiac development, autophagy, and contractile dysfunction. Understanding the mechanisms that govern mitochondrial fission/fusion is paramount in developing new treatment strategies for human diseases in which defects in fission or fusion is the primary underlying defect. Here, we provide a comprehensive overview of the cellular targets and molecular signaling pathways that govern mitochondrial dynamics under normal and disease conditions. (Circ J 2014; 78: 803-810).
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Affiliation(s)
- Rimpy Dhingra
- Department of Physiology, Pharmacology & Therapeutics, The Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, University of Manitoba
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242
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Affiliation(s)
- Bradford G Hill
- From the Institute of Molecular Cardiology, Department of Medicine, Diabetes and Obesity Center, Department of Biochemistry and Molecular Biology, and Department of Physiology and Biophysics, University of Louisville, KY
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