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Heidler J, Cabrera-Orefice A, Wittig I, Heyne E, Tomczak JN, Petersen B, Henze D, Pohjoismäki JLO, Szibor M. Hyperbaric oxygen treatment reveals spatiotemporal OXPHOS plasticity in the porcine heart. PNAS NEXUS 2024; 3:pgae210. [PMID: 38881840 PMCID: PMC11179111 DOI: 10.1093/pnasnexus/pgae210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 05/17/2024] [Indexed: 06/18/2024]
Abstract
Cardiomyocytes meet their high ATP demand almost exclusively by oxidative phosphorylation (OXPHOS). Adequate oxygen supply is an essential prerequisite to keep OXPHOS operational. At least two spatially distinct mitochondrial subpopulations facilitate OXPHOS in cardiomyocytes, i.e. subsarcolemmal (SSM) and interfibrillar mitochondria (IFM). Their intracellular localization below the sarcolemma or buried deep between the sarcomeres suggests different oxygen availability. Here, we studied SSM and IFM isolated from piglet hearts and found significantly lower activities of electron transport chain enzymes and F1FO-ATP synthase in IFM, indicative for compromised energy metabolism. To test the contribution of oxygen availability to this outcome, we ventilated piglets under hyperbaric hyperoxic (HBO) conditions for 240 min. HBO treatment raised OXPHOS enzyme activities in IFM to the level of SSM. Complexome profiling analysis revealed that a high proportion of the F1FO-ATP synthase in the IFM was in a disassembled state prior to the HBO treatment. Upon increased oxygen availability, the enzyme was found to be largely assembled, which may account for the observed increase in OXPHOS complex activities. Although HBO also induced transcription of genes involved in mitochondrial biogenesis, a full proteome analysis revealed only minimal alterations, meaning that HBO-mediated tissue remodeling is an unlikely cause for the observed differences in OXPHOS. We conclude that a previously unrecognized oxygen-regulated mechanism endows cardiac OXPHOS with spatiotemporal plasticity that may underlie the enormous metabolic and contractile adaptability of the heart.
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Affiliation(s)
- Juliana Heidler
- Functional Proteomics, Institute of Cardiovascular Physiology, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
- Experimental Vascular Surgery, University Clinic of Vascular Surgery, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Alfredo Cabrera-Orefice
- Functional Proteomics, Institute of Cardiovascular Physiology, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Ilka Wittig
- Functional Proteomics, Institute of Cardiovascular Physiology, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Estelle Heyne
- Department of Cardiothoracic Surgery, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Friedrich Schiller University of Jena, 07747 Jena, Germany
| | - Jan-Niklas Tomczak
- Functional Proteomics, Institute of Cardiovascular Physiology, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Bjoern Petersen
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institute (FLI), 31535 Mariensee, Germany
| | - Dirk Henze
- Praxis für Anästhesiologie, Dr. Henze & Partner GbR, 06116 Halle (Saale), Germany
| | - Jaakko L O Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, 80101 Joensuu, Finland
| | - Marten Szibor
- Department of Cardiothoracic Surgery, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Friedrich Schiller University of Jena, 07747 Jena, Germany
- Faculty of Medicine and Health Technology, Tampere University, 33014 Tampere, Finland
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2
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Sultan A, Singh J, Howarth FC. Mechanisms underlying electro-mechanical dysfunction in the Zucker diabetic fatty rat heart: a model of obesity and type 2 diabetes. Heart Fail Rev 2021; 25:873-886. [PMID: 31654177 DOI: 10.1007/s10741-019-09872-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Diabetes mellitus (DM) is a major and worsening global health problem, currently affecting over 450 million people and reducing their quality of life. Type 2 diabetes mellitus (T2DM) accounts for more than 90% of DM and the global epidemic of obesity, which largely explains the dramatic increase in the incidence and prevalence of T2DM in the past 20 years. Obesity is a major risk factor for DM which is a major cause of morbidity and mortality in diabetic patients. The electro-mechanical function of the heart is frequently compromised in diabetic patients. The aim of this review is to discuss the pathophysiology of electro-mechanical dysfunction in the diabetic heart and in particular, the Zucker diabetic fatty (ZDF) rat heart, a well-studied model of T2DM and obesity.
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Affiliation(s)
- Ahmed Sultan
- Department of Physiology, College of Medicine & Health Sciences, UAE University, P.O. Box 17666, Al Ain, UAE
| | - Jaipaul Singh
- School of Forensic and Applied Sciences, University of Central Lancashire, Preston, Lancashire, UK
| | - Frank Christopher Howarth
- Department of Physiology, College of Medicine & Health Sciences, UAE University, P.O. Box 17666, Al Ain, UAE.
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3
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Collins HE, Kane MS, Litovsky SH, Darley-Usmar VM, Young ME, Chatham JC, Zhang J. Mitochondrial Morphology and Mitophagy in Heart Diseases: Qualitative and Quantitative Analyses Using Transmission Electron Microscopy. FRONTIERS IN AGING 2021; 2:670267. [PMID: 35822027 PMCID: PMC9261312 DOI: 10.3389/fragi.2021.670267] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 03/26/2021] [Indexed: 01/21/2023]
Abstract
Transmission electron microscopy (TEM) has long been an important technique, capable of high degree resolution and visualization of subcellular structures and organization. Over the last 20 years, TEM has gained popularity in the cardiovascular field to visualize changes at the nanometer scale in cardiac ultrastructure during cardiovascular development, aging, and a broad range of pathologies. Recently, the cardiovascular TEM enabled the studying of several signaling processes impacting mitochondrial function, such as mitochondrial fission/fusion, autophagy, mitophagy, lysosomal degradation, and lipophagy. The goals of this review are to provide an overview of the current usage of TEM to study cardiac ultrastructural changes; to understand how TEM aided the visualization of mitochondria, autophagy, and mitophagy under normal and cardiovascular disease conditions; and to discuss the overall advantages and disadvantages of TEM and potential future capabilities and advancements in the field.
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Affiliation(s)
- Helen E. Collins
- Division of Environmental Medicine, Department of Medicine, University of Louisville, KY, United States
| | - Mariame Selma Kane
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Silvio H. Litovsky
- Division of Anatomic Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Victor M. Darley-Usmar
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Martin E. Young
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - John C. Chatham
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jianhua Zhang
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
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4
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Hu LYR, Kontrogianni-Konstantopoulos A. Proteomic Analysis of Myocardia Containing the Obscurin R4344Q Mutation Linked to Hypertrophic Cardiomyopathy. Front Physiol 2020; 11:478. [PMID: 32528308 PMCID: PMC7247546 DOI: 10.3389/fphys.2020.00478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/20/2020] [Indexed: 12/25/2022] Open
Abstract
Obscurin is a giant cytoskeletal protein with structural and regulatory roles encoded by the OBSCN gene. Recently, mutations in OBSCN were associated with the development of different forms of cardiomyopathies, including hypertrophic cardiomyopathy (HCM). We previously reported that homozygous mice carrying the HCM-linked R4344Q obscurin mutation develop arrhythmia by 1-year of age under sedentary conditions characterized by increased heart rate, frequent incidents of premature ventricular contractions, and episodes of spontaneous ventricular tachycardia. In an effort to delineate the molecular mechanisms that contribute to the observed arrhythmic phenotype, we subjected protein lysates prepared from left ventricles of 1-year old R4344Q and wild-type mice to comparative proteomics analysis using tandem mass spectrometry; raw data are available via ProteomeXchange with identifier PXD017314. We found that the expression levels of proteins involved in cardiac function and disease, cytoskeletal organization, electropotential regulation, molecular transport and metabolism were significantly altered. Moreover, phospho-proteomic evaluation revealed changes in the phosphorylation profile of Ca2+ cycling proteins, including sAnk1.5, a major binding partner of obscurin localized in the sarcoplasmic reticulum; notably, this is the first report indicating that sAnk1 undergoes phosphorylation. Taken together, our findings implicate obscurin in diverse cellular processes within the myocardium, which is consistent with its multiple binding partners, localization in different subcellular compartments, and disease association.
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Affiliation(s)
- Li-Yen R Hu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, United States
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5
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Yu M, Du H, Wang B, Chen J, Lu F, Peng S, Sun Y, Liu N, Sun X, Shiyun D, Zhao Y, Wang Y, Zhao D, Lu F, Zhang W. Exogenous H 2S Induces Hrd1 S-sulfhydration and Prevents CD36 Translocation via VAMP3 Ubiquitylation in Diabetic Hearts. Aging Dis 2020; 11:286-300. [PMID: 32257542 PMCID: PMC7069459 DOI: 10.14336/ad.2019.0530] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/30/2019] [Indexed: 12/21/2022] Open
Abstract
Hydrogen sulfide (H2S) plays physiological roles in vascular tone regulation, cytoprotection, and ATP synthesis. HMG-CoA reductase degradation protein (Hrd1), an E3 ubiquitin ligase, is involved in protein trafficking. H2S may play a role in controlling fatty acid uptake in diabetic cardiomyopathy (DCM) in a manner correlated with modulation of Hrd1 S-sulfhydration; however, this role remains to be elucidated. The aim of the present study was to examine whether H2S can attenuate lipid accumulation and to explain the possible mechanisms involved in the regulation of the H2S-Hrd1/VAMP3 pathway. Db/db mice and neonatal rat cardiomyocytes treated with high glucose, palmitate and oleate were used as animal and cellular models of type 2 diabetes, respectively. The expression of cystathionine-γ-lyase (CSE), Hrd1, CD36 and VAMP3 was detected by Western blot analysis. In addition, Hrd1 was mutated at Cys115, and Hrd1 S-sulfhydration was examined using an S-sulfhydration assay. VAMP3 ubiquitylation was investigated by immunoprecipitation. Lipid droplet formation was tested by TEM, BODIPY 493/503 staining and oil red O staining. The expression of CSE and Hrd1 was decreased in db/db mice compared to control mice, whereas CD36 and VAMP3 expression was increased. NaHS administration reduced droplet formation, and exogenous H2S restored Hrd1 expression, modified S-sulfhydration, and decreased VAMP3 expression in the plasma membrane. Using LC-MS/MS analysis, we identified 85 proteins with decreased ubiquitylation, including 3 vesicle-associated membrane proteins, in the cardiac tissues of model db/db mice compared with NaHS-treated db/db mice. Overexpression of Hrd1 mutated at Cys115 diminished VAMP3 ubiquitylation, whereas it increased CD36 and VAMP3 expression and droplet formation. siRNA-mediated Hrd1 deletion increased the expression of CD36 in the cell membrane. These findings suggested that H2S regulates VAMP3 ubiquitylation via Hrd1 S-sulfhydration at Cys115 to prevent CD36 translocation in diabetes.
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Affiliation(s)
- Miao Yu
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Haining Du
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Bingzhu Wang
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Jian Chen
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Fangping Lu
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Shuo Peng
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Yu Sun
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Ning Liu
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Xiaojiao Sun
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Dong Shiyun
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Yajun Zhao
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Yan Wang
- 2Department of Urologic Surgery, First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Dechao Zhao
- 3Department of Cardiology, First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Fanghao Lu
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China
| | - Weihua Zhang
- 1Department of Pathophysiology, Harbin Medical University, Harbin, China.,4Key Laboratory of Cardiovascular Medicine Research (Harbin Medical University), Ministry of Education, Harbin, 150086, China
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6
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McGarrah RW, Zhang GF, Christopher BA, Deleye Y, Walejko JM, Page S, Ilkayeva O, White PJ, Newgard CB. Dietary branched-chain amino acid restriction alters fuel selection and reduces triglyceride stores in hearts of Zucker fatty rats. Am J Physiol Endocrinol Metab 2020; 318:E216-E223. [PMID: 31794262 PMCID: PMC7052576 DOI: 10.1152/ajpendo.00334.2019] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Elevations in circulating levels of branched-chain amino acids (BCAAs) are associated with a variety of cardiometabolic diseases and conditions. Restriction of dietary BCAAs in rodent models of obesity lowers circulating BCAA levels and improves whole-animal and skeletal-muscle insulin sensitivity and lipid homeostasis, but the impact of BCAA supply on heart metabolism has not been studied. Here, we report that feeding a BCAA-restricted chow diet to Zucker fatty rats (ZFRs) causes a shift in cardiac fuel metabolism that favors fatty acid relative to glucose catabolism. This is illustrated by an increase in labeling of acetyl-CoA from [1-13C]palmitate and a decrease in labeling of acetyl-CoA and malonyl-CoA from [U-13C]glucose, accompanied by a decrease in cardiac hexokinase II and glucose transporter 4 protein levels. Metabolomic profiling of heart tissue supports these findings by demonstrating an increase in levels of a host of fatty-acid-derived metabolites in hearts from ZFRs and Zucker lean rats (ZLRs) fed the BCAA-restricted diet. In addition, the twofold increase in cardiac triglyceride stores in ZFRs compared with ZLRs fed on chow diet is eliminated in ZFRs fed on the BCAA-restricted diet. Finally, the enzymatic activity of branched-chain ketoacid dehydrogenase (BCKDH) is not influenced by BCAA restriction, and levels of BCAA in the heart instead reflect their levels in circulation. In summary, reducing BCAA supply in obesity improves cardiac metabolic health by a mechanism independent of alterations in BCKDH activity.
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Affiliation(s)
- Robert W McGarrah
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
- Cardiology Division, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Guo-Fang Zhang
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
- Endocrinology Division, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Bridgette A Christopher
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
- Cardiology Division, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Yann Deleye
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
| | - Jacquelyn M Walejko
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
| | - Stephani Page
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
| | - Olga Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
| | - Phillip J White
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
- Endocrinology Division, Department of Medicine, Duke University Medical Center, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina
- Endocrinology Division, Department of Medicine, Duke University Medical Center, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina
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7
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van Woerden G, van Veldhuisen DJ, Rienstra M, Westenbrink BD. Myocardial adiposity in heart failure with preserved ejection fraction: the plot thickens. Eur J Heart Fail 2019; 22:455-457. [PMID: 31769136 DOI: 10.1002/ejhf.1653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Gijs van Woerden
- Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Dirk J van Veldhuisen
- Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Michiel Rienstra
- Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - B Daan Westenbrink
- Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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8
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Colasante C, Chen J, Ahlemeyer B, Baumgart-Vogt E. Peroxisomes in cardiomyocytes and the peroxisome / peroxisome proliferator-activated receptor-loop. Thromb Haemost 2017; 113:452-63. [DOI: 10.1160/th14-06-0497] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 12/18/2014] [Indexed: 01/29/2023]
Abstract
SummaryIt is well established that the heart is strongly dependent on fatty acid metabolism. In cardiomyocytes there are two distinct sites for the β-oxidisation of fatty acids: the mitochondrion and the peroxisome. Although the metabolism of these two organelles is believed to be tightly coupled, the nature of this relationship has not been fully investigated. Recent research has established the significant contribution of mitochondrial function to cardiac ATP production under normal and pathological conditions. In contrast, limited information is available on peroxisomal function in the heart. This is despite these organelles harbouring metabolic pathways that are potentially cardioprotective, and findings that patients with peroxisomal diseases, such as adult Refsum’s disease, can develop heart failure. In this article, we provide a comprehensive overview on the current knowledge of peroxisomes and the regulation of lipid metabolism by PPARs in cardiomyocytes. We also present new experimental evidence on the differential expression of peroxisome-related genes in the heart chambers and demonstrate that even a mild peroxisomal biogenesis defect (Pex11α-/- ) can induce profound alterations in the cardiomyocyte’s peroxisomal compartment and related gene expression, including the concomitant deregulation of specific PPARs. The possible impact of peroxisomal dysfunction in the heart is discussed and a model for the modulation of myocardial metabolism via a peroxisome/PPAR-loop is proposed.
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9
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Koncsos G, Varga ZV, Baranyai T, Boengler K, Rohrbach S, Li L, Schlüter KD, Schreckenberg R, Radovits T, Oláh A, Mátyás C, Lux Á, Al-Khrasani M, Komlódi T, Bukosza N, Máthé D, Deres L, Barteková M, Rajtík T, Adameová A, Szigeti K, Hamar P, Helyes Z, Tretter L, Pacher P, Merkely B, Giricz Z, Schulz R, Ferdinandy P. Diastolic dysfunction in prediabetic male rats: Role of mitochondrial oxidative stress. Am J Physiol Heart Circ Physiol 2016; 311:H927-H943. [PMID: 27521417 DOI: 10.1152/ajpheart.00049.2016] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 07/25/2016] [Indexed: 12/23/2022]
Abstract
Although incidence and prevalence of prediabetes are increasing, little is known about its cardiac effects. Therefore, our aim was to investigate the effect of prediabetes on cardiac function and to characterize parameters and pathways associated with deteriorated cardiac performance. Long-Evans rats were fed with either control or high-fat chow for 21 wk and treated with a single low dose (20 mg/kg) of streptozotocin at week 4 High-fat and streptozotocin treatment induced prediabetes as characterized by slightly elevated fasting blood glucose, impaired glucose and insulin tolerance, increased visceral adipose tissue and plasma leptin levels, as well as sensory neuropathy. In prediabetic animals, a mild diastolic dysfunction was observed, the number of myocardial lipid droplets increased, and left ventricular mass and wall thickness were elevated; however, no molecular sign of fibrosis or cardiac hypertrophy was shown. In prediabetes, production of reactive oxygen species was elevated in subsarcolemmal mitochondria. Expression of mitofusin-2 was increased, while the phosphorylation of phospholamban and expression of Bcl-2/adenovirus E1B 19-kDa protein-interacting protein 3 (BNIP3, a marker of mitophagy) decreased. However, expression of other markers of cardiac auto- and mitophagy, mitochondrial dynamics, inflammation, heat shock proteins, Ca2+/calmodulin-dependent protein kinase II, mammalian target of rapamycin, or apoptotic pathways were unchanged in prediabetes. This is the first comprehensive analysis of cardiac effects of prediabetes indicating that mild diastolic dysfunction and cardiac hypertrophy are multifactorial phenomena that are associated with early changes in mitophagy, cardiac lipid accumulation, and elevated oxidative stress and that prediabetes-induced oxidative stress originates from the subsarcolemmal mitochondria.
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Affiliation(s)
- Gábor Koncsos
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Zoltán V Varga
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary; Laboratory of Cardiovascular Physiology and Tissue Injury, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Tamás Baranyai
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Kerstin Boengler
- Institute of Physiology, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Susanne Rohrbach
- Institute of Physiology, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Ling Li
- Institute of Physiology, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Klaus-Dieter Schlüter
- Institute of Physiology, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Rolf Schreckenberg
- Institute of Physiology, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Tamás Radovits
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Attila Oláh
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Csaba Mátyás
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Árpád Lux
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Mahmoud Al-Khrasani
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Tímea Komlódi
- Department of Medical Biochemistry, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Nóra Bukosza
- Institute of Pathophysiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Domokos Máthé
- Department of Biophysics and Radiation Biology, Faculty of Medicine, Semmelweis University, Budapest, Hungary; CROmed Translational Research Centers, Budapest, Hungary
| | - László Deres
- 1st Department of Internal Medicine, Faculty of Medicine, University of Pécs, Pécs, Hungary
| | - Monika Barteková
- Institute of Physiology, Faculty of Medicine, Comenius University in Bratislava, Slovakia; Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Tomáš Rajtík
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Slovakia
| | - Adriana Adameová
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Slovakia
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Péter Hamar
- Institute of Pathophysiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Zsuzsanna Helyes
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine and Szentágothai Research Centre & MTA-PTE NAP B Chronic Pain Research Group, University of Pécs, Pécs, Hungary; and
| | - László Tretter
- Department of Medical Biochemistry, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Pál Pacher
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary; Laboratory of Cardiovascular Physiology and Tissue Injury, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Béla Merkely
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Zoltán Giricz
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary;
| | - Rainer Schulz
- Institute of Physiology, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Péter Ferdinandy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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10
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Guarini G, Kiyooka T, Ohanyan V, Pung YF, Marzilli M, Chen YR, Chen CL, Kang PT, Hardwick JP, Kolz CL, Yin L, Wilson GL, Shokolenko I, Dobson JG, Fenton R, Chilian WM. Impaired coronary metabolic dilation in the metabolic syndrome is linked to mitochondrial dysfunction and mitochondrial DNA damage. Basic Res Cardiol 2016; 111:29. [PMID: 27040114 DOI: 10.1007/s00395-016-0547-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 03/09/2016] [Indexed: 12/11/2022]
Abstract
Mitochondrial dysfunction in obesity and diabetes can be caused by excessive production of free radicals, which can damage mitochondrial DNA. Because mitochondrial DNA plays a key role in the production of ATP necessary for cardiac work, we hypothesized that mitochondrial dysfunction, induced by mitochondrial DNA damage, uncouples coronary blood flow from cardiac work. Myocardial blood flow (contrast echocardiography) was measured in Zucker lean (ZLN) and obese fatty (ZOF) rats during increased cardiac metabolism (product of heart rate and arterial pressure, i.v. norepinephrine). In ZLN increased metabolism augmented coronary blood flow, but in ZOF metabolic hyperemia was attenuated. Mitochondrial respiration was impaired and ROS production was greater in ZOF than ZLN. These were associated with mitochondrial DNA (mtDNA) damage in ZOF. To determine if coronary metabolic dilation, the hyperemic response induced by heightened cardiac metabolism, is linked to mitochondrial function we introduced recombinant proteins (intravenously or intraperitoneally) in ZLN and ZOF to fragment or repair mtDNA, respectively. Repair of mtDNA damage restored mitochondrial function and metabolic dilation, and reduced ROS production in ZOF; whereas induction of mtDNA damage in ZLN reduced mitochondrial function, increased ROS production, and attenuated metabolic dilation. Adequate metabolic dilation was also associated with the extracellular release of ADP, ATP, and H2O2 by cardiac myocytes; whereas myocytes from rats with impaired dilation released only H2O2. In conclusion, our results suggest that mitochondrial function plays a seminal role in connecting myocardial blood flow to metabolism, and integrity of mtDNA is central to this process.
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Affiliation(s)
- Giacinta Guarini
- Cardio-Thoracic and Vascular Department, University of Pisa, Pisa, Italy
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - Takahiko Kiyooka
- Division of Cardiology, Tokai University Oiso Hospital, Oiso, Japan
| | - Vahagn Ohanyan
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - Yuh Fen Pung
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
- Department of Biomedical Science, University of Nottingham, Semenyih, Malaysia
| | - Mario Marzilli
- Cardio-Thoracic and Vascular Department, University of Pisa, Pisa, Italy
| | - Yeong Renn Chen
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - Chwen Lih Chen
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - Patrick T Kang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - James P Hardwick
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - Christopher L Kolz
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - Liya Yin
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA
| | - Glenn L Wilson
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, USA
| | - Inna Shokolenko
- Department of Biomedical Sciences, University of South Alabama, Mobile, USA
| | - James G Dobson
- Department of Microbiology and Physiological Systems, University of Massachusetts, Boston, USA
| | - Richard Fenton
- Department of Microbiology and Physiological Systems, University of Massachusetts, Boston, USA
| | - William M Chilian
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA.
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11
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Riojas-Hernández A, Bernal-Ramírez J, Rodríguez-Mier D, Morales-Marroquín FE, Domínguez-Barragán EM, Borja-Villa C, Rivera-Álvarez I, García-Rivas G, Altamirano J, García N. Enhanced oxidative stress sensitizes the mitochondrial permeability transition pore to opening in heart from Zucker Fa/fa rats with type 2 diabetes. Life Sci 2015; 141:32-43. [DOI: 10.1016/j.lfs.2015.09.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 08/18/2015] [Accepted: 09/22/2015] [Indexed: 12/13/2022]
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12
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Male-Specific Cardiac Dysfunction in CTP:Phosphoethanolamine Cytidylyltransferase (Pcyt2)-Deficient Mice. Mol Cell Biol 2015; 35:2641-57. [PMID: 25986609 DOI: 10.1128/mcb.00380-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/14/2015] [Indexed: 12/15/2022] Open
Abstract
Phosphatidylethanolamine (PE) is the most abundant inner membrane phospholipid. PE synthesis from ethanolamine and diacylglycerol is regulated primarily by CTP:phosphoethanolamine cytidylyltransferase (Pcyt2). Pcyt2(+/-) mice have reduced PE synthesis and, as a consequence, perturbed glucose and fatty acid metabolism, which gradually leads to the development of hyperlipidemia, obesity, and insulin resistance. Glucose and fatty acid uptake and the corresponding transporters Glut4 and Cd36 are similarly impaired in male and female Pcyt2(+/-) hearts. These mice also have similarly reduced phosphatidylinositol 3-kinase (PI3K)/Akt1 signaling and increased reactive oxygen species (ROS) production in the heart. However, only Pcyt2(+/-) males develop hypertension and cardiac hypertrophy. Pcyt2(+/-) males have upregulated heart AceI expression, heart phospholipids enriched in arachidonic acid and other n-6 polyunsaturated fatty acids, and dramatically increased ROS production in the aorta. In contrast, Pcyt2(+/-) females have unmodified heart phospholipids but have reduced heart triglyceride levels and altered expression of the structural genes Acta (low) and Myh7 (high). These changes together protect Pcyt2(+/-) females from cardiac dysfunction under conditions of reduced glucose and fatty acid uptake and heart insulin resistance. Our data identify Pcyt2 and membrane PE biogenesis as important determinants of gender-specific differences in cardiac lipids and heart function.
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13
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Obesity and cancer progression: is there a role of fatty acid metabolism? BIOMED RESEARCH INTERNATIONAL 2015; 2015:274585. [PMID: 25866768 PMCID: PMC4383231 DOI: 10.1155/2015/274585] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 11/24/2014] [Indexed: 12/30/2022]
Abstract
Currently, there is renewed interest in elucidating the metabolic characteristics of cancer and how these characteristics may be exploited as therapeutic targets. Much attention has centered on glucose, glutamine and de novo lipogenesis, yet the metabolism of fatty acids that arise from extracellular, as well as intracellular, stores as triacylglycerol has received much less attention. This review focuses on the key pathways of fatty acid metabolism, including uptake, esterification, lipolysis, and mitochondrial oxidation, and how the regulators of these pathways are altered in cancer. Additionally, we discuss the potential link that fatty acid metabolism may serve between obesity and changes in cancer progression.
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14
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Nabben M, van Bree BWJ, Lenaers E, Hoeks J, Hesselink MKC, Schaart G, Gijbels MJJ, Glatz JFC, da Silva GJJ, de Windt LJ, Tian R, Mike E, Skapura DG, Wehrens XHT, Schrauwen P. Lack of UCP3 does not affect skeletal muscle mitochondrial function under lipid-challenged conditions, but leads to sudden cardiac death. Basic Res Cardiol 2014; 109:447. [PMID: 25344084 DOI: 10.1007/s00395-014-0447-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 10/07/2014] [Accepted: 10/15/2014] [Indexed: 12/29/2022]
Abstract
UCP3's exact physiological function in lipid handling in skeletal and cardiac muscle remains unknown. Interestingly, etomoxir, a fat oxidation inhibitor and strong inducer of UCP3, is proposed for treating both diabetes and heart failure. We hypothesize that the upregulation of UCP3 upon etomoxir serves to protect mitochondria against lipotoxicity. To evaluate UCP3's role in skeletal muscle (skm) and heart under lipid-challenged conditions, the effect of UCP3 ablation was examined in a state of dysbalance between fat availability and oxidative capacity. Wild type (WT) and UCP3(-/-) mice were subjected to high-fat feeding for 14 days. From day 6 onwards, they were given either saline or etomoxir. Etomoxir treatment induced an increase in markers of lipotoxicity in skm compared to saline. This increase upon etomoxir was similar for both, WT and UCP3(-/-) mice, suggesting that UCP3 does not play a role in protection against lipotoxicity. Interestingly, we observed 25 % mortality in UCP3(-/-)s upon etomoxir administration vs. 11 % in WTs. This increased mortality in UCP3(-/-) compared to WT mice could not be explained by differences in cardiac lipotoxicity, apoptosis, fibrosis (histology, immunohistochemistry), oxidative capacity (respirometry) or function (echocardiography). Electrophysiology demonstrated, however, prolonged QRS and QTc intervals and greater susceptibility to ventricular tachycardia upon programmed electrical stimulation in etomoxir-treated UCP3(-/-)s versus WTs. Isoproterenol administration after pacing resulted in 75 % mortality in UCP3(-/-)s vs. 14 % in WTs. Our results argue against a protective role for UCP3 on skm metabolism under lipid overload, but suggest UCP3 to be crucial in prevention of arrhythmias upon lipid-challenged conditions.
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Affiliation(s)
- Miranda Nabben
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Bianca W J van Bree
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Ellen Lenaers
- Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Joris Hoeks
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Matthijs K C Hesselink
- Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Gert Schaart
- Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Marion J J Gijbels
- Department of Molecular Genetics, CARIM School for Cardiovascular Research, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Jan F C Glatz
- Department of Molecular Genetics, CARIM School for Cardiovascular Research, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Gustavo J J da Silva
- Department of Cardiology, CARIM School for Cardiovascular Research, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Leon J de Windt
- Department of Cardiology, CARIM School for Cardiovascular Research, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Rong Tian
- Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington, Seattle, WA, USA
| | - Elise Mike
- Department of Molecular Physiology and Biophysics and Medicine (Cardiology), Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Darlene G Skapura
- Department of Molecular Physiology and Biophysics and Medicine (Cardiology), Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Xander H T Wehrens
- Department of Molecular Physiology and Biophysics and Medicine (Cardiology), Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Patrick Schrauwen
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, PO Box 616, 6200 MD Maastricht, The Netherlands
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15
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Haynie KR, Vandanmagsar B, Wicks SE, Zhang J, Mynatt RL. Inhibition of carnitine palymitoyltransferase1b induces cardiac hypertrophy and mortality in mice. Diabetes Obes Metab 2014; 16:757-60. [PMID: 24330405 PMCID: PMC4057362 DOI: 10.1111/dom.12248] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/19/2013] [Accepted: 12/03/2013] [Indexed: 02/04/2023]
Abstract
Recent reports suggest that short-term pharmacological carnitine palmitoyltransferase 1 (Cpt1) inhibition improves skeletal muscle glucose tolerance and insulin sensitivity. Although this appears promising for the treatment of diabetes, these Cpt1 inhibitors are not specific to skeletal muscle and target multiple Cpt1 isoforms. To assess the effects of inhibiting the Cpt1b isoform we generated mice with a heart- and skeletal muscle-specific deletion of the Cpt1b, Cpt1b(HM-/-). These mice seem to develop normally with similar bodyweights as control mice. However, premature mortality was observed by 15 weeks of age in the Cpt1b(HM-/-) mice. The hearts of Cpt1b(HM-/-) mice were four times the size of controls. Cpt1b(HM-/-) mice were also subject to stress-induced seizures that accompanied an increased risk for premature mortality. Our data suggests that prolonged Cpt1b inhibition poses severe cardiac risk and emphasizes that attempts to improve insulin sensitivity by targeting Cpt1 with current inhibitors is not viable.
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Affiliation(s)
- KR Haynie
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
| | - B Vandanmagsar
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
| | - SE Wicks
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
| | - J Zhang
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
| | - RL Mynatt
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
- Corresponding Author: Randall L. Mynatt, 6400 Perkins Road, Baton Rouge, LA 70808, 225-763-3100 (phone), 225-763-0273 (fax),
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16
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Aon MA, Bhatt N, Cortassa SC. Mitochondrial and cellular mechanisms for managing lipid excess. Front Physiol 2014; 5:282. [PMID: 25132820 PMCID: PMC4116787 DOI: 10.3389/fphys.2014.00282] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/10/2014] [Indexed: 12/16/2022] Open
Abstract
Current scientific debates center on the impact of lipids and mitochondrial function on diverse aspects of human health, nutrition and disease, among them the association of lipotoxicity with the onset of insulin resistance in skeletal muscle, and with heart dysfunction in obesity and diabetes. Mitochondria play a fundamental role in aging and in prevalent acute or chronic diseases. Lipids are main mitochondrial fuels however these molecules can also behave as uncouplers and inhibitors of oxidative phosphorylation. Knowledge about the functional composition of these contradictory effects and their impact on mitochondrial-cellular energetics/redox status is incomplete. Cells store fatty acids (FAs) as triacylglycerol and package them into cytoplasmic lipid droplets (LDs). New emerging data shows the LD as a highly dynamic storage pool of FAs that can be used for energy reserve. Lipid excess packaging into LDs can be seen as an adaptive response to fulfilling energy supply without hindering mitochondrial or cellular redox status and keeping low concentration of lipotoxic intermediates. Herein we review the mechanisms of action and utilization of lipids by mitochondria reported in liver, heart and skeletal muscle under relevant physiological situations, e.g., exercise. We report on perilipins, a family of proteins that associate with LDs in response to loading of cells with lipids. Evidence showing that in addition to physical contact, mitochondria and LDs exhibit metabolic interactions is presented and discussed. A hypothetical model of channeled lipid utilization by mitochondria is proposed. Direct delivery and channeled processing of lipids in mitochondria could represent a reliable and efficient way to maintain reactive oxygen species (ROS) within levels compatible with signaling while ensuring robust and reliable energy supply.
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Affiliation(s)
- Miguel A Aon
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Niraj Bhatt
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Sonia C Cortassa
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
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17
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Holloway GP, Han XX, Jain SS, Bonen A, Chabowski A. Chronic muscle stimulation improves insulin sensitivity while increasing subcellular lipid droplets and reducing selected diacylglycerol and ceramide species in obese Zucker rats. Diabetologia 2014; 57:832-40. [PMID: 24458200 DOI: 10.1007/s00125-014-3169-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/02/2014] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Although insulin resistance has been associated with accumulations of specific intramuscular fatty acids and altered subcellular localisation of lipid droplets, these concepts remain controversial. Therefore, we aimed to identify specific intramuscular fatty acids and subcellular lipid localisations associated with improved insulin sensitivity following chronic muscle contraction. METHODS In lean and insulin-resistant obese Zucker rats the tibialis anterior muscle was stimulated (6 h/day for 6 days). Thereafter, muscles were examined for insulin sensitivity, intramuscular lipid droplet localisation and triacylglycerol (TAG), diacylglycerol (DAG) and ceramide fatty acid composition. RESULTS In lean and obese animals, regardless of muscle type, chronic muscle contraction improved muscle insulin sensitivity and increased intramuscular levels of total and most C14-C22 TAG fatty acids (p < 0.05). Therefore, accumulation in subcellular lipid droplet compartments reflected the oversupply of lipids within muscle. In contrast, improvements in insulin sensitivity induced by muscle contraction were associated with reductions in specific DAG and ceramide species that were not uniform in red and white muscle of obese rats. However, these reductions were insufficient to fully normalise insulin sensitivity, indicating that other mechanisms are involved. CONCLUSIONS/INTERPRETATION Reductions in 18 C length DAG and ceramide species were the most consistent in red and white muscle and therefore may represent therapeutic targets for improving insulin sensitivity.
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Affiliation(s)
- Graham P Holloway
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada, NIG, 2W1,
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18
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Manrique C, DeMarco VG, Aroor AR, Mugerfeld I, Garro M, Habibi J, Hayden MR, Sowers JR. Obesity and insulin resistance induce early development of diastolic dysfunction in young female mice fed a Western diet. Endocrinology 2013; 154:3632-42. [PMID: 23885014 PMCID: PMC5398539 DOI: 10.1210/en.2013-1256] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 07/16/2013] [Indexed: 01/09/2023]
Abstract
Cardiovascular disease (CVD), including heart failure, constitutes the main source of morbidity and mortality in men and women with diabetes. Although healthy young women are protected against CVD, postmenopausal and diabetic women lose this CVD protection. Obesity, insulin resistance, and diabetes promote heart failure in females, and diastolic dysfunction is the earliest manifestation of this heart failure. To examine the mechanisms promoting diastolic dysfunction in insulin-resistant females, this investigation evaluated the impact of 8 weeks of a high-fructose/high-fat Western diet (WD) on insulin sensitivity and cardiac structure and function in young C57BL6/J female versus male mice. Insulin sensitivity was determined by hyperinsulinemic-euglycemic clamps and two-dimensional echocardiograms were used to evaluate cardiac function. Both males and females developed systemic insulin resistance after 8 weeks of a WD. However, only the females developed diastolic dysfunction. The diastolic dysfunction promoted by the WD was accompanied by increases in collagen 1, a marker of stiffness, increased oxidative stress, reduced insulin metabolic signaling, and increased mitochondria and cardiac microvascular alterations as determined by electron microscopy. Aldosterone (a promoter of cardiac stiffness) levels were higher in females compared with males but were not affected by the WD in either gender. These data suggest a predisposition toward developing early diastolic heart failure in females exposed to a WD. These data are consistent with the notion that higher aldosterone levels, in concert with insulin resistance, may promote myocardial stiffness and diastolic dysfunction in response to overnutrition in females.
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Affiliation(s)
- Camila Manrique
- MD, Professor of Medicine and Medical Pharmacology and Physiology, University of Missouri, D109 Diabetes Center Health Sciences Center, One Hospital Drive, Columbia, Missouri 65212.
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19
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Aroor AR, Sowers JR, Bender SB, Nistala R, Garro M, Mugerfeld I, Hayden MR, Johnson MS, Salam M, Whaley-Connell A, Demarco VG. Dipeptidylpeptidase inhibition is associated with improvement in blood pressure and diastolic function in insulin-resistant male Zucker obese rats. Endocrinology 2013; 154:2501-13. [PMID: 23653460 PMCID: PMC3689282 DOI: 10.1210/en.2013-1096] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Diastolic dysfunction is a prognosticator for future cardiovascular events that demonstrates a strong correlation with obesity. Pharmacological inhibition of dipeptidylpeptidase-4 (DPP-4) to increase the bioavailability of glucagon-like peptide-1 is an emerging therapy for control of glycemia in type 2 diabetes patients. Accumulating evidence suggests that glucagon-like peptide-1 has insulin-independent actions in cardiovascular tissue. However, it is not known whether DPP-4 inhibition improves obesity-related diastolic dysfunction. Eight-week-old Zucker obese (ZO) and Zucker lean rats were fed normal chow diet or diet containing the DPP-4 inhibitor, linagliptin (LGT), for 8 weeks. Plasma DPP-4 activity was 3.3-fold higher in ZO compared with Zucker lean rats and was reduced by 95% with LGT treatment. LGT improved echocardiographic and pressure volume-derived indices of diastolic function that were impaired in ZO control rats, without altering food intake or body weight gain during the study period. LGT also blunted elevated blood pressure progression in ZO rats involving improved skeletal muscle arteriolar function, without reducing left ventricular hypertrophy, fibrosis, or oxidative stress in ZO hearts. Expression of phosphorylated- endothelial nitric oxide synthase (eNOS)(Ser1177), total eNOS, and sarcoplasmic reticulum calcium ATPase 2a protein was elevated in the LGT-treated ZO heart, suggesting improved Ca(2+) handling. The ZO myocardium had an abnormal mitochondrial sarcomeric arrangement and cristae structure that were normalized by LGT. These studies suggest that LGT reduces blood pressure and improves intracellular Cai(2+) mishandling and cardiomyocyte ultrastructure, which collectively result in improvements in diastolic function in the absence of reductions in left ventricular hypertrophy, fibrosis, or oxidative stress in insulin-resistant ZO rats.
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Affiliation(s)
- Annayya R Aroor
- Department of Internal Medicine, University of Missouri School of Medicine, and Diabetes and Cardiovascular Center, Columbia, MO 65212, USA
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20
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Carley AN, Bi J, Wang X, Banke NH, Dyck JRB, O'Donnell JM, Lewandowski ED. Multiphasic triacylglycerol dynamics in the intact heart during acute in vivo overexpression of CD36. J Lipid Res 2012; 54:97-106. [PMID: 23099442 DOI: 10.1194/jlr.m029991] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cardiac triacylglycerol (TAG) stores buffer the intracellular availability of long chain fatty acid (LCFA) that act as nuclear receptor ligands, substrate for lipotoxic derivatives, and high energy-yield fuel. The kinetic characteristics of TAG turnover and homeostatic mechanisms linking uptake and storage dynamics in hearts have until now remained elusive. This work examines TAG pool dynamics in the intact beating heart, under normal conditions and in response to acute gene expression-induced changes in CD36. Dynamic mode (13)C NMR elucidated multiple kinetic processes in (13)C-palmitate incorporation into TAG: an initial, saturable exponential component and a slower linear rate. Although previous work indicates the linear component to reflect TAG turnover, we hypothesized the saturable exponential to reflect transport of LCFA across the sarcolemma. Thus, we overexpressed the LCFA transporter CD36 through cardiac-specific adenoviral infection in vivo. Within 72 h, CD36 expression was increased 40% in intact hearts, accelerating the exponential phase relative to PBS-infused hearts. TAG turnover also increased with elevations in adipose triglyceride lipase (ATGL) and a modest increase in diacylglycerol acyltransferase 1 (DGAT1), without a significant expansion of the intracellular lipid pools. The results demonstrate a dynamic system of reciprocal gene regulation that couples saturable LCFA uptake across the sarcolemma to TAG synthesis/lipolysis rates.
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Affiliation(s)
- Andrew N Carley
- Program in Integrative Cardiac Metabolism, Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, IL, USA
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21
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García-Rúa V, Otero MF, Lear PV, Rodríguez-Penas D, Feijóo-Bandín S, Noguera-Moreno T, Calaza M, Álvarez-Barredo M, Mosquera-Leal A, Parrington J, Brugada J, Portolés M, Rivera M, González-Juanatey JR, Lago F. Increased expression of fatty-acid and calcium metabolism genes in failing human heart. PLoS One 2012; 7:e37505. [PMID: 22701570 PMCID: PMC3368932 DOI: 10.1371/journal.pone.0037505] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 04/19/2012] [Indexed: 01/08/2023] Open
Abstract
Background Heart failure (HF) involves alterations in metabolism, but little is known about cardiomyopathy-(CM)-specific or diabetes-independent alterations in gene expression of proteins involved in fatty-acid (FA) uptake and oxidation or in calcium-(Ca2+)-handling in the human heart. Methods RT-qPCR was used to quantify mRNA expression and immunoblotting to confirm protein expression in left-ventricular myocardium from patients with HF (n = 36) without diabetes mellitus of ischaemic (ICM, n = 16) or dilated (DCM, n = 20) cardiomyopathy aetiology, and non-diseased donors (CTL, n = 6). Results Significant increases in mRNA of genes regulating FA uptake (CD36) and intracellular transport (Heart-FA-Binding Protein (HFABP)) were observed in HF patients vs CTL. Significance was maintained in DCM and confirmed at protein level, but not in ICM. mRNA was higher in DCM than ICM for peroxisome-proliferator-activated-receptor-alpha (PPARA), PPAR-gamma coactivator-1-alpha (PGC1A) and CD36, and confirmed at the protein level for PPARA and CD36. Transcript and protein expression of Ca2+-handling genes (Two-Pore-Channel 1 (TPCN1), Two-Pore-Channel 2 (TPCN2), and Inositol 1,4,5-triphosphate Receptor type-1 (IP3R1)) increased in HF patients relative to CTL. Increases remained significant for TPCN2 in all groups but for TPCN1 only in DCM. There were correlations between FA metabolism and Ca2+-handling genes expression. In ICM there were six correlations, all distinct from those found in CTL. In DCM there were also six (all also different from those found in CTL): three were common to and three distinct from ICM. Conclusion DCM-specific increases were found in expression of several genes that regulate FA metabolism, which might help in the design of aetiology-specific metabolic therapies in HF. Ca2+-handling genes TPCN1 and TPCN2 also showed increased expression in HF, while HF- and CM-specific positive correlations were found among several FA and Ca2+-handling genes.
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Affiliation(s)
- Vanessa García-Rúa
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - Manuel Francisco Otero
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
- Department of Clinical Chemistry, University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - Pamela Virginia Lear
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - Diego Rodríguez-Penas
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - Sandra Feijóo-Bandín
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - Teresa Noguera-Moreno
- Unit of Biostatistical Research, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Manuel Calaza
- Laboratory 10, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - María Álvarez-Barredo
- Department of Cardiology, University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - Ana Mosquera-Leal
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - John Parrington
- Department of Pharmacology, Oxford University, Oxford, United Kingdom
| | - Josep Brugada
- Cardiology Department, Thorax Institute, Hospital Clinic, Barcelona, Spain
| | | | | | - José Ramón González-Juanatey
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
- Department of Cardiology, University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
| | - Francisca Lago
- Laboratory of Cellular and Molecular Cardiology, Santiago Institute of Biomedical Research (IDIS), University of Santiago de Compostela Clinical Hospital (CHUS), Santiago de Compostela, Spain
- * E-mail:
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22
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Zhang Y, Li F, Patterson AD, Wang Y, Krausz KW, Neale G, Thomas S, Nachagari D, Vogel P, Vore M, Gonzalez FJ, Schuetz JD. Abcb11 deficiency induces cholestasis coupled to impaired β-fatty acid oxidation in mice. J Biol Chem 2012; 287:24784-94. [PMID: 22619174 DOI: 10.1074/jbc.m111.329318] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The bile salt export pump (BSEP) is an ATP-binding cassette transporter that serves as the primary system for removing bile salts from the liver. In humans, deficiency of BSEP, which is encoded by the ABCB11 gene, causes severe progressive cholestatic liver disease from early infancy. In previous studies of Abcb11 deficiency in mice generated on a mixed genetic background, the animals did not recapitulate the human disease. We reasoned that ABCB11 deficiency may cause unique changes in hepatic metabolism that are predictive of liver injury. To test this possibility, we first determined that Abcb11 knock-out (KO) C57BL/6J mice recapitulate human deficiency. Before the onset of cholestasis, Abcb11 KO mice have altered hepatic lipid metabolism coupled with reduced expression of genes important in mitochondrial fatty acid oxidation. This was associated with increased serum free-fatty acids, reduced total white adipose, and marked impairment of long-chain fatty acid β-oxidation. Importantly, metabolomic analysis confirmed that Abcb11 KO mice have impaired mitochondrial fatty acid β-oxidation with the elevated fatty acid metabolites phenylpropionylglycine and phenylacetylglycine. These metabolic changes precede cholestasis but may be of relevance to cholestatic disease progression because altered fatty acid metabolism can enhance reactive oxygen species that might exacerbate cholestatic liver damage.
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Affiliation(s)
- Yuanyuan Zhang
- Department of Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105, USA
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Lally JSV, Snook LA, Han XX, Chabowski A, Bonen A, Holloway GP. Subcellular lipid droplet distribution in red and white muscles in the obese Zucker rat. Diabetologia 2012; 55:479-88. [PMID: 22101973 DOI: 10.1007/s00125-011-2367-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 10/10/2011] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS Little is known about the subcellular distribution of lipids in insulin-resistant skeletal muscle. However, it has recently been suggested that lipid accumulation in the subsarcolemmal region directly contributes to insulin resistance. Therefore we hypothesised that regional differences in lipid distribution in insulin-resistant muscle may be mediated by: (1) a reduction in fatty acid trafficking into mitochondria; and/or (2) a regional increase in the enzymes regulating lipid synthesis. METHODS Transmission electron microscopy was used to quantify lipid droplet and mitochondrial abundance in the subsarcolemmal and intermyofibrillar compartments in red and white muscles from lean and obese Zucker rats. To estimate rates of lipid trafficking into mitochondria, the metabolic fate of radiolabelled palmitate was determined. Key enzymes of triacylglycerol synthesis were also determined in each subcellular region. RESULTS Subsarcolemmal-compartmentalised lipids represented a small absolute fraction of the overall lipid content in muscle, as regardless of fibre composition (red/white) or phenotype (lean/obese), lipid droplets were more prevalent in the intermyofibrillar region, whereas insulin-resistant white muscles were devoid of subsarcolemmal-compartmentalised lipid droplets. While, in obese animals, lipid droplets accumulated in both subcellular regions, in red muscle of these animals lipids only appeared to be trafficked away from intermyofibrillar mitochondria, a process that cannot be explained by regional differences in the abundance of triacylglycerol esterification enzymes. CONCLUSIONS/INTERPRETATION Lipid accumulation in the subsarcolemmal region is not necessary for insulin resistance. In the intermyofibrillar compartment, the diversion of lipids away from mitochondria in insulin-resistant animals probably contributes to lipid accumulation in this subcellular area.
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Affiliation(s)
- J S V Lally
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada N1G 2W1
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Hoshino D, Yoshida Y, Holloway GP, Lally J, Hatta H, Bonen A. Clenbuterol, a β2-adrenergic agonist, reciprocally alters PGC-1 alpha and RIP140 and reduces fatty acid and pyruvate oxidation in rat skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2012; 302:R373-84. [DOI: 10.1152/ajpregu.00183.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Clenbuterol, a β2-adrenergic agonist, reduces mitochondrial content and enzyme activities in skeletal muscle, but the mechanism involved has yet to be identified. We examined whether clenbuterol-induced changes in the muscles' metabolic profile and the intrinsic capacity of mitochondria to oxidize substrates are associated with reductions in the nuclear receptor coactivator PGC-1 alpha and/or an increase in the nuclear corepressor RIP140. In rats, clenbuterol was provided in the drinking water (30 mg/l). In 3 wk, this increased body (8%) and muscle weights (12–17%). In red (R) and white (W) muscles, clenbuterol induced reductions in mitochondrial content (citrate synthase: R, 27%; W, 52%; cytochrome- c oxidase: R, 24%; W, 34%), proteins involved in fatty acid transport (fatty acid translocase/CD36: R, 36%; W, 35%) and oxidation [β-hydroxyacyl CoA dehydrogenase (β-HAD): R, 33%; W, 62%], glucose transport (GLUT4: R, 8%; W, 13%), lactate transport monocarboxylate transporter (MCT1: R, 61%; W, 37%), and pyruvate oxidation (PDHE1α, R, 18%; W, 12%). Concurrently, only red muscle lactate dehydrogenase activity (25%) and MCT4 (31%) were increased. Palmitate oxidation was reduced in subsarcolemmal (SS) (R, 30%; W, 52%) and intermyofibrillar (IMF) mitochondria (R, 17%; W, 44%) along with reductions in β-HAD activity (SS: R, 17%; W, 51%; IMF: R, 20%; W, 57%). Pyruvate oxidation was only reduced in SS mitochondria (R, 20%; W, 28%), but this was not attributable solely to PDHE1α, which was reduced in both SS (R, 21%; W, 20%) and IMF mitochondria (R, 15%; W, 43%). These extensive metabolic changes induced by clenbuterol were associated with reductions in PGC-1α (R, 37%; W, 32%) and increases in RIP140 (R, 23%; W, 21%). This is the first evidence that clenbuterol appears to exert its metabolic effects via simultaneous and reciprocal changes in the nuclear receptor coactivator PGC-1α and the nuclear corepressor RIP140.
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Affiliation(s)
- Daisuke Hoshino
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan; and
| | - Yuko Yoshida
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Graham P. Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - James Lally
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Hideo Hatta
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan; and
| | - Arend Bonen
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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25
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Pung YF, Rocic P, Murphy MP, Smith RAJ, Hafemeister J, Ohanyan V, Guarini G, Yin L, Chilian WM. Resolution of mitochondrial oxidative stress rescues coronary collateral growth in Zucker obese fatty rats. Arterioscler Thromb Vasc Biol 2011; 32:325-34. [PMID: 22155454 DOI: 10.1161/atvbaha.111.241802] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE We have previously found abrogated ischemia-induced coronary collateral growth in Zucker obese fatty (ZOF) rats compared with Zucker lean (ZLN) rats. Because ZOF rats have structural abnormalities in their mitochondria suggesting dysfunction and also show increased production of O(2), we hypothesized that mitochondrial dysfunction caused by oxidative stress impairs coronary collateral growth in ZOF. METHODS AND RESULTS Increased levels of reactive oxygen species were observed in aortic endothelium and smooth muscle cells in ZOF rats compared with ZLN rats. Reactive oxygen species levels were decreased by the mitochondria-targeted antioxidants MitoQuinone (MQ) and MitoTempol (MT) as assessed by MitoSox Red and dihydroethidine staining. Lipid peroxides (a marker of oxidized lipids) were increased in ZOF by ≈47% compared with ZLN rats. The elevation in oxidative stress was accompanied by increased antioxidant enzymes, except glutathione peroxidase-1, and by increased uncoupling protein-2 in ZOF versus ZLN rats. In addition, elevated respiration rates were also observed in the obese compared with lean rats. Administration of MQ significantly normalized the metabolic profiles and reduced lipid peroxides in ZOF rats to the same level observed in lean rats. The protective effect of MQ also suppressed the induction of uncoupling protein-2 in the obese rats. Resolution of mitochondrial oxidative stress by MQ or MT restored coronary collateral growth to the same magnitude observed in ZLN rats in response to repetitive ischemia. CONCLUSIONS We conclude that mitochondrial oxidative stress and dysfunction play a key role in disrupting coronary collateral growth in obesity and the metabolic syndrome, and elimination of the mitochondrial oxidative stress with MQ or MT rescues collateral growth.
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Affiliation(s)
- Yuh Fen Pung
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
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26
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Abstract
Type 2 diabetes and obesity are associated with systemic inflammation, generalized enlargement of fat depots, and uncontrolled release of fatty acids (FA) into the circulation. These features support the occurrence of cardiac adiposity, which is characterized by an increase in intramyocardial triglyceride content and an enlargement of the volume of fat surrounding the heart and vessels. Both events may initially serve as protective mechanisms to portion energy, but their excessive expansion can lead to myocardial damage and heart disease. FA overload promotes FA oxidation and the accumulation of triglycerides and metabolic intermediates, which can impair calcium signaling, β-oxidation, and glucose utilization. This leads to damaged mitochondrial function and increased production of reactive oxygen species, pro-apoptotic, and inflammatory molecules, and finally to myocardial inflammation and dysfunction. Triglyceride accumulation is associated with left ventricular hypertrophy and dysfunction. The enlargement of epicardial fat in patients with metabolic disorders, and coronary artery disease, is associated with the release of proinflammatory and proatherogenic cytokines to the subtending tissues. In this review, we examine the evidence supporting a causal relationship linking FA overload and cardiac dysfunction. Also, we disentangle the separate roles of FA oxidation and triglyceride accumulation in causing cardiac damage. Finally, we focus on the mechanisms of inflammation development in the fatty heart, before summarizing the available evidence in humans. Current literature confirms the dual (protective and detrimental) role of cardiac fat, and suggests prospective studies to establish the pathogenetic (when and how) and possible prognostic value of this potential biomarker in humans.
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Affiliation(s)
- Maria A Guzzardi
- Institute of Clinical Physiology, National Research Council (CNR), Via Moruzzi 1, 56124 Pisa, Italy
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27
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Pulakat L, DeMarco VG, Ardhanari S, Chockalingam A, Gul R, Whaley-Connell A, Sowers JR. Adaptive mechanisms to compensate for overnutrition-induced cardiovascular abnormalities. Am J Physiol Regul Integr Comp Physiol 2011; 301:R885-95. [PMID: 21813874 DOI: 10.1152/ajpregu.00316.2011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In conditions of overnutrition, cardiac cells must cope with a multitude of extracellular signals generated by changes in nutrient load (glucose, amino acids, and lipids) and the hormonal milieu [increased insulin (INS), ANG II, and adverse cytokine/adipokine profile]. Herein, we review the diverse compensatory/adaptive mechanisms that counter the deleterious effects of excess nutrients and growth factors. We largely focus the discussion on evidence obtained from Zucker obese (ZO) and Zucker diabetic fatty (ZDF) rats, which are useful models to evaluate adaptive and maladaptive metabolic, structural, and functional cardiac remodeling. One adaptive mechanism present in the INS-resistant ZO, but absent in the diabetic ZDF heart, involves an interaction between the nutrient sensor kinase mammalian target of rapamycin complex 1 (mTORC1) and ANG II-type 2 receptor (AT2R). Recent evidence supports a cardioprotective role for the AT2R; for example, suppression of AT2R activation interferes with antihypertrophic/antifibrotic effects of AT1R blockade, and AT2R agonism improves cardiac structure and function. We propose a scenario, whereby mTORC1-signaling-mediated increase in AT2R expression in the INS-resistant ZO heart is a cardioprotective adaptation to overnutrition. In contrast to the ZO rat, heart tissues of ZDF rats do not show activation of mTORC1. We posit that such a lack of activation of the mTOR↔AT2R integrative pathway in cardiac tissue under conditions of obesity-induced diabetes may be a metabolic switch associated with INS deficiency and clinical diabetes.
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Affiliation(s)
- Lakshmi Pulakat
- University of Missouri School of Medicine, Department of Internal Medicine, Columbia, Missouri 65212, USA
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28
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Khalid AM, Hafstad AD, Larsen TS, Severson DL, Boardman N, Hagve M, Berge RK, Aasum E. Cardioprotective effect of the PPAR ligand tetradecylthioacetic acid in type 2 diabetic mice. Am J Physiol Heart Circ Physiol 2011; 300:H2116-22. [DOI: 10.1152/ajpheart.00357.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tetradecylthioacetic acid (TTA) is a novel peroxisome proliferator-activated receptor (PPAR) ligand with marked hypolipidemic and insulin-sensitizing effects in obese models. TTA has recently been shown to attenuate dyslipidemia in patients with type 2 diabetes, corroborating the potential for TTA in antidiabetic therapy. In a recent study on normal mice, we showed that TTA increased myocardial fatty acid (FA) oxidation, which was associated with decreased cardiac efficiency and impaired postischemic functional recovery. The aim of the present study was, therefore, to elucidate the effects of TTA treatment (0.5%, 8 days) on cardiac metabolism and function in a hyperlipidemic type 2 diabetic model. We found that TTA treatment increased myocardial FA oxidation, not only in nondiabetic ( db/+) mice but also in diabetic ( db/db) mice, despite a clear lipid-lowering effect. Although TTA had deleterious effects in hearts from nondiabetic mice (decreased efficiency and impaired mitochondrial respiratory capacity), these effects were not observed in db/db hearts. In db/db hearts, TTA improved ischemic tolerance, an effect that is most likely related to the antioxidant property of TTA. The present study strongly advocates the need for investigation of the cardiac effects of PPAR ligands used in antidiabetic/hypolipidemic therapy, because of their pleiotropic properties.
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Affiliation(s)
- Ahmed M. Khalid
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø
| | - Anne Dragøy Hafstad
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø
| | - Terje S. Larsen
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø
| | - David L. Severson
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Neoma Boardman
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø
| | - Martin Hagve
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø
| | - Rolf K. Berge
- The Lipid Research Group, Institute of Medicine, University of Bergen, Norway; and
| | - Ellen Aasum
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø
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