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Bristow CL. Lipoproteins in Negative Feedback with Alpha-1 Antitrypsin. Methods Mol Biol 2024; 2750:167-174. [PMID: 38108976 DOI: 10.1007/978-1-0716-3605-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Alpha-1 antitrypsin deficiency patients (AATD) have lower risk of myocardial infarction, a cardiovascular disease that is related to increased remnant cholesterol levels, but not to low-density lipoprotein (LDL) levels. However, when AAT is knocked out in mice (AAT-KO), inflammatory-related, cholesterol metabolism-related, and lipid metabolism-related gene expression in mouse liver was increased, and these data support previous evidence from clinic patients and from a small clinical trial that AAT is in negative feedback regulation with LDL. Herein is a brief summary to examine the roles of AAT in these overlapping pathways.
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Affiliation(s)
- Cynthia L Bristow
- Alpha-1 Biologics, Long Island High Technology Incubator, Stony Brook University, Stony Brook, NY, USA.
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2
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Da Dalt L, Cabodevilla AG, Goldberg IJ, Norata GD. Cardiac lipid metabolism, mitochondrial function, and heart failure. Cardiovasc Res 2023; 119:1905-1914. [PMID: 37392421 PMCID: PMC10681665 DOI: 10.1093/cvr/cvad100] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/31/2023] [Accepted: 03/01/2023] [Indexed: 07/03/2023] Open
Abstract
A fine balance between uptake, storage, and the use of high energy fuels, like lipids, is crucial in the homeostasis of different metabolic tissues. Nowhere is this balance more important and more precarious than in the heart. This highly energy-demanding muscle normally oxidizes almost all the available substrates to generate energy, with fatty acids being the preferred source under physiological conditions. In patients with cardiomyopathies and heart failure, changes in the main energetic substrate are observed; these hearts often prefer to utilize glucose rather than oxidizing fatty acids. An imbalance between uptake and oxidation of fatty acid can result in cellular lipid accumulation and cytotoxicity. In this review, we will focus on the sources and uptake pathways used to direct fatty acids to cardiomyocytes. We will then discuss the intracellular machinery used to either store or oxidize these lipids and explain how disruptions in homeostasis can lead to mitochondrial dysfunction and heart failure. Moreover, we will also discuss the role of cholesterol accumulation in cardiomyocytes. Our discussion will attempt to weave in vitro experiments and in vivo data from mice and humans and use several human diseases to illustrate metabolism gone haywire as a cause of or accomplice to cardiac dysfunction.
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Affiliation(s)
- Lorenzo Da Dalt
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, Milan, Italy
| | - Ainara G Cabodevilla
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University Grossman School of Medicine, 550 1st Ave., New York, NY, USA
| | - Ira J Goldberg
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University Grossman School of Medicine, 550 1st Ave., New York, NY, USA
| | - Giuseppe Danilo Norata
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Via Balzaretti 9, Milan, Italy
- Center for the Study of Atherosclerosis, E. Bassini Hospital, Via Massimo Gorki 50, Cinisello Balsamo, Italy
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3
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Exploring the Pattern of Metabolic Alterations Causing Energy Imbalance via PPARα Dysregulation in Cardiac Muscle During Doxorubicin Treatment. Cardiovasc Toxicol 2022; 22:436-461. [PMID: 35157213 DOI: 10.1007/s12012-022-09725-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 02/02/2022] [Indexed: 12/14/2022]
Abstract
Cardiotoxicity by anthracycline antineoplastic drug doxorubicin is one of the systemic toxicity of the cardiovascular system. The mechanism responsible for doxorubicin cardiotoxicity and lipid metabolism remains elusive. The current study tested the hypotheses that the role of peroxisome proliferator-activated receptor α (PPARα) in the progress of doxorubicin-induced cardiomyopathy and its mechanism behind lipid metabolism. In the present study, male rats were subjected to intraperitoneal injection (5-week period) of doxorubicin with different dosages such as low dosage (1.5 mg/kg body weight) and high dosage (15 mg/kg body weight) to induce doxorubicin cardiomyopathy. Myocardial PPARα was impaired in both low dosage and high dosage of doxorubicin-treated rats in a dose-dependent manner. The attenuated level of PPARα impairs the expression of the genes involved in mitochondrial transporter, fatty acid transportation, lipolysis, lipid metabolism, and fatty acid oxidation. Moreover, it disturbs the reverse triacylglycerol transporter apolipoprotein B-100 (APOB) in the myocardium. Doxorubicin elevates the circulatory lipid profile and glucose. Further aggravated lipid profile in circulation impedes the metabolism of lipid in cardiac tissue, which causes a lipotoxic condition in the heart and subsequently associated disease for the period of doxorubicin treatment. Elevated lipids in the circulation translocate into the heart dysregulates lipid metabolism in the heart, which causes augmented oxidative stress and necro-apoptosis and mediates lipotoxic conditions. This finding determines the mechanistic role of doxorubicin-disturbed lipid metabolism via PPARα, which leads to cardiac dysfunction.
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4
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Koyani CN, Scheruebel S, Jin G, Kolesnik E, Zorn-Pauly K, Mächler H, Hoefler G, von Lewinski D, Heinzel FR, Pelzmann B, Malle E. Hypochlorite-Modified LDL Induces Arrhythmia and Contractile Dysfunction in Cardiomyocytes. Antioxidants (Basel) 2021; 11:25. [PMID: 35052529 PMCID: PMC8772905 DOI: 10.3390/antiox11010025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/21/2021] [Indexed: 02/05/2023] Open
Abstract
Neutrophil-derived myeloperoxidase (MPO) and its potent oxidant, hypochlorous acid (HOCl), gained attention as important oxidative mediators in cardiac damage and dysfunction. As cardiomyocytes generate low-density lipoprotein (LDL)-like particles, we aimed to identify the footprints of proatherogenic HOCl-LDL, which adversely affects cellular signalling cascades in various cell types, in the human infarcted myocardium. We performed immunohistochemistry for MPO and HOCl-LDL in human myocardial tissue, investigated the impact of HOCl-LDL on electrophysiology and contractility in primary cardiomyocytes, and explored underlying mechanisms in HL-1 cardiomyocytes and human atrial appendages using immunoblot analysis, qPCR, and silencing experiments. HOCl-LDL reduced ICa,L and IK1, and increased INaL, leading to altered action potential characteristics and arrhythmic events including early- and delayed-afterdepolarizations. HOCl-LDL altered the expression and function of CaV1.2, RyR2, NCX1, and SERCA2a, resulting in impaired contractility and Ca2+ homeostasis. Elevated superoxide anion levels and oxidation of CaMKII were mediated via LOX-1 signaling in HL-1 cardiomyocytes. Furthermore, HOCl-LDL-mediated alterations of cardiac contractility and electrophysiology, including arrhythmic events, were ameliorated by the CaMKII inhibitor KN93 and the INaL blocker, ranolazine. This study provides an explanatory framework for the detrimental effects of HOCl-LDL compared to native LDL and cardiac remodeling in patients with high MPO levels during the progression of cardiovascular disease.
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Affiliation(s)
- Chintan N. Koyani
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria;
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
| | - Susanne Scheruebel
- Division of Biophysics, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria; (S.S.); (K.Z.-P.)
| | - Ge Jin
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
- The 2nd Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Ewald Kolesnik
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
| | - Klaus Zorn-Pauly
- Division of Biophysics, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria; (S.S.); (K.Z.-P.)
| | - Heinrich Mächler
- Department of Surgery, Division of Cardiac Surgery, Medical University of Graz, 8036 Graz, Austria;
| | - Gerald Hoefler
- Diagnostic and Research Center for Molecular BioMedicine, Diagnostic and Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria;
| | - Dirk von Lewinski
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
| | - Frank R. Heinzel
- Department of Internal Medicine and Cardiology, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, 13353 Berlin, Germany;
- Deutsches Zentrum für Herz-Kreislauf-Forschung (German Centre for Cardiovascular Research), Partner Site Berlin, 10785 Berlin, Germany
| | - Brigitte Pelzmann
- Division of Biophysics, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria; (S.S.); (K.Z.-P.)
| | - Ernst Malle
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria;
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5
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Impact of IL10, MTP, SOD2, and APOE Gene Polymorphisms on the Severity of Liver Fibrosis Induced by HCV Genotype 4. Viruses 2021; 13:v13040714. [PMID: 33924242 PMCID: PMC8074775 DOI: 10.3390/v13040714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 12/13/2022] Open
Abstract
Complications of hepatitis C virus (HCV) chronic infection cause ~400,000 deaths worldwide annually. One complication, liver fibrosis, is influenced by host genetic factors. Genes influencing fibrosis include immune, metabolic, oxidative stress, and viral entry genes, such as interleukin 10 (IL10), microsomal triglyceride-transfer protein (MTP), superoxide dismutase-2 (SOD2), and apolipoprotein E (APOE)-encoding genes, respectively. Thus, correlating variations in these genes with HCV-induced fibrosis represents an attractive biomarker for the prognosis of fibrosis severity in chronically infected patients. Here, we aimed to test whether polymorphisms in IL10, MTP, SOD2, and APOE genes correlated with the severity of fibrosis induced by HCV genotype 4 (HCV-gt4) in a cohort of chronically infected Egyptian patients. Our results demonstrate a significant association between the severity of fibrosis and specific SNPs in IL-10, SOD2, and ApoE-encoding genes. Haplotype-combination analysis for IL10, MTP, SOD2, and APOE showed statistically significant associations between specific haplotype combinations and fibrosis severity. Identifying biomarkers correlating with the severity of HCV-gt4-induced fibrosis would significantly impact precision prophylaxis and treatment of patients at risk.
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6
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Larsen LE, Smith MA, Abbey D, Korn A, Reeskamp LF, Hand NJ, Holleboom AG. Hepatocyte-like cells derived from induced pluripotent stem cells: A versatile tool to understand lipid disorders. Atherosclerosis 2020; 303:8-14. [PMID: 32460140 DOI: 10.1016/j.atherosclerosis.2020.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 02/19/2020] [Accepted: 03/18/2020] [Indexed: 12/12/2022]
Abstract
Dyslipidemias are strongly linked to the development of atherosclerotic cardiovascular disease. Most dyslipidemias find their origin in the liver. In recent years, the differentiation of induced pluripotent stem cells (iPSCs) into hepatocyte-like cells has provided a versatile platform for the functional study of various dyslipidemias, both rare genetic dyslipidemia as well as common lipid disorders associated with insulin resistance or non-alcoholic fatty liver disease. In addition, iPSC-derived hepatocytes can serve as a cell model for developing novel lipid lowering therapies and have the potential of regenerative medicine. This review provides an overview of these developments.
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Affiliation(s)
- Lars E Larsen
- Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands
| | - Mikhaila A Smith
- Departments of Genetics and Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA
| | - Deepti Abbey
- Departments of Genetics and Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA
| | - Amber Korn
- Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands; Department of Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands
| | - Laurens F Reeskamp
- Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands; Department of Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands
| | - Nicholas J Hand
- Departments of Genetics and Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA.
| | - Adriaan G Holleboom
- Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands; Department of Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands.
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7
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Walsh MT, Celestin OM, Thierer JH, Rajan S, Farber SA, Hussain MM. Model systems for studying the assembly, trafficking, and secretion of apoB lipoproteins using fluorescent fusion proteins. J Lipid Res 2020; 61:316-327. [PMID: 31888978 DOI: 10.1194/jlr.ra119000259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 12/24/2019] [Indexed: 11/20/2022] Open
Abstract
apoB exists as apoB100 and apoB48, which are mainly found in hepatic VLDLs and intestinal chylomicrons, respectively. Elevated plasma levels of apoB-containing lipoproteins (Blps) contribute to coronary artery disease, diabetes, and other cardiometabolic conditions. Studying the mechanisms that drive the assembly, intracellular trafficking, secretion, and function of Blps remains challenging. Our understanding of the intracellular and intraorganism trafficking of Blps can be greatly enhanced, however, with the availability of fusion proteins that can help visualize Blp transport within cells and between tissues. We designed three plasmids expressing human apoB fluorescent fusion proteins: apoB48-GFP, apoB100-GFP, and apoB48-mCherry. In Cos-7 cells, transiently expressed fluorescent apoB proteins colocalized with calnexin and were only secreted if cells were cotransfected with microsomal triglyceride transfer protein. The secreted apoB-fusion proteins retained the fluorescent protein and were secreted as lipoproteins with flotation densities similar to plasma HDL and LDL. In a rat hepatoma McA-RH7777 cell line, the human apoB100 fusion protein was secreted as VLDL- and LDL-sized particles, and the apoB48 fusion proteins were secreted as LDL- and HDL-sized particles. To monitor lipoprotein trafficking in vivo, the apoB48-mCherry construct was transiently expressed in zebrafish larvae and was detected throughout the liver. These experiments show that the addition of fluorescent proteins to the C terminus of apoB does not disrupt their assembly, localization, secretion, or endocytosis. The availability of fluorescently labeled apoB proteins will facilitate the exploration of the assembly, degradation, and transport of Blps and help to identify novel compounds that interfere with these processes via high-throughput screening.
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Affiliation(s)
- Meghan T Walsh
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York
| | - Oni M Celestin
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
| | - James H Thierer
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
| | - Sujith Rajan
- Department of Foundations of Medicine, New York University Long Island School of Medicine, Mineola, NY.,Diabetes and Obesity Research Center, New York University Winthrop Hospital, Mineola, NY
| | - Steven A Farber
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
| | - M Mahmood Hussain
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York .,Department of Foundations of Medicine, New York University Long Island School of Medicine, Mineola, NY.,Diabetes and Obesity Research Center, New York University Winthrop Hospital, Mineola, NY.,Department of Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY
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8
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Klevstig M, Arif M, Mannila M, Svedlund S, Mardani I, Ståhlman M, Andersson L, Lindbom M, Miljanovic A, Franco-Cereceda A, Eriksson P, Jeppsson A, Gan LM, Levin M, Mardinoglu A, Ehrenborg E, Borén J. Cardiac expression of the microsomal triglyceride transport protein protects the heart function during ischemia. J Mol Cell Cardiol 2019; 137:1-8. [PMID: 31533023 DOI: 10.1016/j.yjmcc.2019.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 09/06/2019] [Indexed: 11/16/2022]
Abstract
AIMS The microsomal triglyceride transport protein (MTTP) is critical for assembly and secretion of apolipoprotein B (apoB)-containing lipoproteins and is most abundant in the liver and intestine. Surprisingly, MTTP is also expressed in the heart. Here we tested the functional relevance of cardiac MTTP expression. MATERIALS AND METHODS We combined clinical studies, advanced expression analysis of human heart biopsies and analyses in genetically modified mice lacking cardiac expression of the MTTP-A isoform of MTTP. RESULTS Our results indicate that lower cardiac MTTP expression in humans is associated with structural and perfusion abnormalities in patients with ischemic heart disease. MTTP-A deficiency in mice heart does not affect total MTTP expression, activity or lipid concentration in the heart. Despite this, MTTP-A deficient mice displayed impaired cardiac function after a myocardial infarction. Expression analysis of MTTP indicates that MTTP expression is linked to cardiac function and responses in the heart. CONCLUSIONS Our results indicate that MTTP may play an important role for the heart function in conjunction to ischemic events.
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Affiliation(s)
- Martina Klevstig
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Muhammad Arif
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Maria Mannila
- Cardiovascular Medicine Unit, Department of Medicine, Center for Molecular Medicine at BioClinicum, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Sara Svedlund
- Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Ismena Mardani
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Marcus Ståhlman
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Linda Andersson
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Malin Lindbom
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Azra Miljanovic
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Anders Franco-Cereceda
- Department of Cardiothoracic Surgery and Anaesthesia, Karolinska University Hospital, Stockholm, Sweden
| | - Per Eriksson
- Cardiovascular Medicine Unit, Department of Medicine, Center for Molecular Medicine at BioClinicum, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Anders Jeppsson
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Li-Ming Gan
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden; Cardiovascular, Renal and Metabolism IMED Biotech Unit, AstraZeneca R&D, Gothenburg, Mölndal, Sweden
| | - Malin Levin
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Adil Mardinoglu
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden; Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Ewa Ehrenborg
- Cardiovascular Medicine Unit, Department of Medicine, Center for Molecular Medicine at BioClinicum, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Jan Borén
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden.
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9
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Curcio CA. Soft Drusen in Age-Related Macular Degeneration: Biology and Targeting Via the Oil Spill Strategies. Invest Ophthalmol Vis Sci 2018; 59:AMD160-AMD181. [PMID: 30357336 PMCID: PMC6733535 DOI: 10.1167/iovs.18-24882] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AMD is a major cause of legal blindness in older adults approachable through multidisciplinary research involving human tissues and patients. AMD is a vascular-metabolic-inflammatory disease, in which two sets of extracellular deposits, soft drusen/basal linear deposit (BLinD) and subretinal drusenoid deposit (SDD), confer risk for end-stages of atrophy and neovascularization. Understanding how deposits form can lead to insights for new preventions and therapy. The topographic correspondence of BLinD and SDD with cones and rods, respectively, suggest newly realized exchange pathways among outer retinal cells and across Bruch's membrane and the subretinal space, in service of highly evolved, eye-specific physiology. This review focuses on soft drusen/BLinD, summarizing evidence that a major ultrastructural component is large apolipoprotein B,E-containing, cholesterol-rich lipoproteins secreted by the retinal pigment epithelium (RPE) that offload unneeded lipids of dietary and outer segment origin to create an atherosclerosis-like progression in the subRPE-basal lamina space. Clinical observations and an RPE cell culture system combine to suggest that soft drusen/BLinD form when secretions of functional RPE back up in the subRPE-basal lamina space by impaired egress across aged Bruch's membrane-choriocapillary endothelium. The soft drusen lifecycle includes growth, anterior migration of RPE atop drusen, then collapse, and atrophy. Proof-of-concept studies in humans and animal models suggest that targeting the “Oil Spill in Bruch's membrane” offers promise of treating a process in early AMD that underlies progression to both end-stages. A companion article addresses the antecedents of soft drusen within the biology of the macula.
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Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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10
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Jun S, Datta S, Wang L, Pegany R, Cano M, Handa JT. The impact of lipids, lipid oxidation, and inflammation on AMD, and the potential role of miRNAs on lipid metabolism in the RPE. Exp Eye Res 2018; 181:346-355. [PMID: 30292489 DOI: 10.1016/j.exer.2018.09.023] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/31/2018] [Accepted: 09/30/2018] [Indexed: 12/17/2022]
Abstract
The accumulation of lipids within drusen, the epidemiologic link of a high fat diet, and the identification of polymorphisms in genes involved in lipid metabolism that are associated with disease risk, have prompted interest in the role of lipid abnormalities in AMD. Despite intensive investigation, our understanding of how lipid abnormalities contribute to AMD development remains unclear. Lipid metabolism is tightly regulated, and its dysregulation can trigger excess lipid accumulation within the RPE and Bruch's membrane. The high oxidative stress environment of the macula can promote lipid oxidation, impairing their original function as well as producing oxidation-specific epitopes (OSE), which unless neutralized, can induce unwanted inflammation that additionally contributes to AMD progression. Considering the multiple layers of lipid metabolism and inflammation, and the ability to simultaneously target multiple pathways, microRNA (miRNAs) have emerged as important regulators of many age-related diseases including atherosclerosis and Alzheimer's disease. These diseases have similar etiologic characteristics such as lipid-rich deposits, oxidative stress, and inflammation with AMD, which suggests that miRNAs might influence lipid metabolism in AMD. In this review, we discuss the contribution of lipids to AMD pathobiology and introduce how miRNAs might affect lipid metabolism during lesion development. Establishing how miRNAs contribute to lipid accumulation in AMD will help to define the role of lipids in AMD, and open new treatment avenues for this enigmatic disease.
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Affiliation(s)
- Sujung Jun
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Sayantan Datta
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Lei Wang
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Roma Pegany
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Marisol Cano
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - James T Handa
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States.
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11
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Chen CY, Huang YF, Ko YJ, Liu YJ, Chen YH, Walzem RL, Chen SE. Obesity-associated cardiac pathogenesis in broiler breeder hens: Development of metabolic cardiomyopathy. Poult Sci 2018; 96:2438-2446. [PMID: 28339731 DOI: 10.3382/ps/pex016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 01/08/2017] [Indexed: 01/15/2023] Open
Abstract
Feed intake is typically restricted (R) in broiler hens to avoid obesity and improve egg production and livability. To determine whether improved heart health contributes to improved livability, fully adult 45-week-old R hens were allowed to consume feed to appetite (ad libitum; AL) up to 10 wk (70 d). Mortality, contractile functions, and morphology at 70 d, and measurements of cardiac hypertrophic remodeling at 7 d and 21 d were made and compared between R and AL hens. Outcomes for cardiac electrophysiology and mortality, reported separately, found increased mortality in AL hens in association with cardiac pathological hypertrophy and contractile dysfunction. The present study aimed to delineate metabolic cardiomyopathies underlying the etiology of obesity-associated cardiac pathology. Metabolic measurements were made in hens continued on R rations or assigned to AL feeding after 7 d and 21 days. AL feeding increased plasma insulin, glucose, and non-esterified fatty acid (NEFA) concentrations by 21 d (P < 0.05). Metabolic cardiomyopathy in AL-hens was confirmed by cardiac triacylglycerol (TG) and ceramide accumulation consistent with up-regulation of related enzyme gene expressions, and by increased indices of oxidation stress (P < 0.05). In contrast to R hens, cardiac pyruvate dehydrogenase (PDH) activity and glucose transporter (GLUT) gene expressions increased progressively while carnitine palmitoyltransferase-1 (CPT-1) transcript levels in AL hens declined from 7 d to 21 d (P < 0.05), reflecting a shift from an oxidative to a more glycolytic metabolism, a typical metabolic derangement associated with cardiac hypertrophic remodeling. Cardiac pathogenesis in AL hens was further indicated by increased leukocyte infiltrates, interleukin-1β (IL-1β) and IL-6 production, cellular apoptosis, interstitial fibrosis, and expression of the heart failure marker myosin heavy chain (MHC-β; cardiac muscle beta) (P < 0.05). Results support the conclusion that diabetic conditions, cardiac inflammation and lipotoxic metabolic derangements act as pathological cues to trigger pathogenic changes along cardiac hypertrophy in AL hens.
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Affiliation(s)
- C Y Chen
- Department of Animal Science, National Chung Hsing University, Taichung, Taiwan
| | - Y F Huang
- Department of Animal Science, National Chung Hsing University, Taichung, Taiwan
| | - Y J Ko
- Department of Animal Science, National Chung Hsing University, Taichung, Taiwan
| | - Y J Liu
- Department of Animal Science, National Chung Hsing University, Taichung, Taiwan
| | - Y H Chen
- Department of Animal Science, National Chung Hsing University, Taichung, Taiwan
| | - R L Walzem
- Department of Poultry Science, Texas A&M University, College Station
| | - S E Chen
- Department of Animal Science, National Chung Hsing University, Taichung, Taiwan.,Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.,Center for the Integrative and Evolutionary Galliformes Genomics, iEGG Center, National Chung Hsing University, Taiwan
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12
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Peretti N. Lessons from chylomicron retention disease: a potential new approach for the treatment of hypercholesterolemia? Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1438259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Noel Peretti
- Hospices Civils de Lyon, Department of Pediatric Nutrition, Hopital Femme Mere Enfant HFME, Bron, France
- Univ-Lyon, CarMeN laboratory, INSERM U1060, INRA U1397, Université Claude Bernard Lyon 1, INSA Lyon, Charles Merieux Medical School, Oullins, France
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13
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Liu Y, Conlon DM, Bi X, Slovik KJ, Shi J, Edelstein HI, Millar JS, Javaheri A, Cuchel M, Pashos EE, Iqbal J, Hussain MM, Hegele RA, Yang W, Duncan SA, Rader DJ, Morrisey EE. Lack of MTTP Activity in Pluripotent Stem Cell-Derived Hepatocytes and Cardiomyocytes Abolishes apoB Secretion and Increases Cell Stress. Cell Rep 2018; 19:1456-1466. [PMID: 28514664 DOI: 10.1016/j.celrep.2017.04.064] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 02/22/2017] [Accepted: 04/21/2017] [Indexed: 01/26/2023] Open
Abstract
Abetalipoproteinemia (ABL) is an inherited disorder of lipoprotein metabolism resulting from mutations in microsomal triglyceride transfer protein (MTTP). In addition to expression in the liver and intestine, MTTP is expressed in cardiomyocytes, and cardiomyopathy has been reported in several ABL cases. Using induced pluripotent stem cells (iPSCs) generated from an ABL patient homozygous for a missense mutation (MTTPR46G), we show that human hepatocytes and cardiomyocytes exhibit defects associated with ABL disease, including loss of apolipoprotein B (apoB) secretion and intracellular accumulation of lipids. MTTPR46G iPSC-derived cardiomyocytes failed to secrete apoB, accumulated intracellular lipids, and displayed increased cell death, suggesting intrinsic defects in lipid metabolism due to loss of MTTP function. Importantly, these phenotypes were reversed after the correction of the MTTPR46G mutation by CRISPR/Cas9 gene editing. Together, these data reveal clear cellular defects in iPSC-derived hepatocytes and cardiomyocytes lacking MTTP activity, including a cardiomyocyte-specific regulated stress response to elevated lipids.
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Affiliation(s)
- Ying Liu
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Donna M Conlon
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xin Bi
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Katherine J Slovik
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jianting Shi
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hailey I Edelstein
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John S Millar
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ali Javaheri
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marina Cuchel
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Evanthia E Pashos
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jahangir Iqbal
- Department of Cell Biology and Pediatrics, State University of New York Downstate Medicine Center, Brooklyn, NY 11203, USA
| | - M Mahmood Hussain
- Department of Cell Biology and Pediatrics, State University of New York Downstate Medicine Center, Brooklyn, NY 11203, USA
| | - Robert A Hegele
- Department of Medicine and Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Wenli Yang
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephen A Duncan
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Daniel J Rader
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Edward E Morrisey
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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14
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Roman-Padilla J, Rodríguez-Rúa A, Carballo C, Manchado M, Hachero-Cruzado I. Phylogeny and expression patterns of two apolipoprotein E genes in the flatfish Senegalese sole. Gene 2018; 643:7-16. [DOI: 10.1016/j.gene.2017.11.078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/15/2017] [Accepted: 11/30/2017] [Indexed: 02/07/2023]
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15
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Goldberg IJ. 2017 George Lyman Duff Memorial Lecture: Fat in the Blood, Fat in the Artery, Fat in the Heart: Triglyceride in Physiology and Disease. Arterioscler Thromb Vasc Biol 2018; 38:700-706. [PMID: 29419410 DOI: 10.1161/atvbaha.117.309666] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/10/2018] [Indexed: 12/31/2022]
Abstract
Cholesterol is not the only lipid that causes heart disease. Triglyceride supplies the heart and skeletal muscles with highly efficient fuel and allows for the storage of excess calories in adipose tissue. Failure to transport, acquire, and use triglyceride leads to energy deficiency and even death. However, overabundance of triglyceride can damage and impair tissues. Circulating lipoprotein-associated triglycerides are lipolyzed by lipoprotein lipase (LpL) and hepatic triglyceride lipase. We inhibited these enzymes and showed that LpL inhibition reduces high-density lipoprotein cholesterol by >50%, and hepatic triglyceride lipase inhibition shifts low-density lipoprotein to larger, more buoyant particles. Genetic variations that reduce LpL activity correlate with increased cardiovascular risk. In contrast, macrophage LpL deficiency reduces macrophage function and atherosclerosis. Therefore, muscle and macrophage LpL have opposite effects on atherosclerosis. With models of atherosclerosis regression that we used to study diabetes mellitus, we are now examining whether triglyceride-rich lipoproteins or their hydrolysis by LpL affect the biology of established plaques. Following our focus on triglyceride metabolism led us to show that heart-specific LpL hydrolysis of triglyceride allows optimal supply of fatty acids to the heart. In contrast, cardiomyocyte LpL overexpression and excess lipid uptake cause lipotoxic heart failure. We are now studying whether interrupting pathways for lipid uptake might prevent or treat some forms of heart failure.
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Affiliation(s)
- Ira J Goldberg
- From the Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, New York University School of Medicine.
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16
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Swift LL, Love JD, Harris CM, Chang BH, Jerome WG. Microsomal triglyceride transfer protein contributes to lipid droplet maturation in adipocytes. PLoS One 2017; 12:e0181046. [PMID: 28793320 PMCID: PMC5549975 DOI: 10.1371/journal.pone.0181046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 06/26/2017] [Indexed: 11/18/2022] Open
Abstract
Previous studies in our laboratory have established the presence of MTP in both white and brown adipose tissue in mice as well as in 3T3-L1 cells. Additional studies demonstrated an increase in MTP levels as 3T3-L1 cells differentiate into adipocytes concurrent with the movement of MTP from the juxtanuclear region of the cell to the surface of lipid droplets. This suggested a role for MTP in lipid droplet biogenesis and/or maturation. To probe the role of MTP in adipocytes, we used a Cre-Lox approach with aP2-Cre and Adipoq-Cre recombinase transgenic mice to knock down MTP expression in brown and white fat of mice. MTP expression was reduced approximately 55% in white fat and 65–80% in brown fat. Reducing MTP expression in adipose tissue had no effect on weight gain or body composition, whether the mice were fed a regular rodent or high fat diet. In addition, serum lipids and unesterified fatty acid levels were not altered in the knockdown mice. Importantly, decreased MTP expression in adipose tissue was associated with smaller lipid droplets in brown fat and smaller adipocytes in white fat. These results combined with our previous studies showing MTP lipid transfer activity is not necessary for lipid droplet initiation or growth in the early stages of differentiation, suggest that a structural feature of the MTP protein is important in lipid droplet maturation. We conclude that MTP protein plays a critical role in lipid droplet maturation, but does not regulate total body fat accumulation.
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Affiliation(s)
- Larry L. Swift
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Research Service, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, United States of America
- * E-mail:
| | - Joseph D. Love
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Carla M. Harris
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Benny H. Chang
- Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - W. Gray Jerome
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
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17
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Lu L, Zhou Q, Chen Z, Chen L. The significant role of the Golgi apparatus in cardiovascular diseases. J Cell Physiol 2017; 233:2911-2919. [PMID: 28574583 DOI: 10.1002/jcp.26039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/01/2017] [Indexed: 12/25/2022]
Abstract
The Golgi apparatus (GA) is a ribbon-like system of stacks which consist of multiple closely apposed flattened cisternae and vesicles usually localized in the juxta-nuclear area. As for the biological functions, the GA plays a major role in protein biosynthesis, post-translational modification, and sorting protein from ER to plasma membrane and other destinations. Structural changes and functional disorder of the GA is associated with various diseases. Moreover, increasing evidence revealed that swelling, poor development, and other morphological alterations of the GA are linked to cardiovascular diseases such as heart failure (HF), arrhythmia, and dilated cardiomyopathy. Furthermore, dysfunction of the GA is also related to cardiovascular diseases since the GA is extremely responsible for transport, glycosylation, biosynthesis, and subcellular distribution of cardiovascular proteins. This review gives a brief overview of the intricate relationship between the GA and cardiovascular diseases. In addition, we provide a further prospective that the GA may provide diagnosis reference for cardiovascular diseases, and changes in the ultrastructure and morphology of the GA such as swelling, poor development, and fragmentation may serve as a reliable index for cardiovascular diseases.
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Affiliation(s)
- Liqun Lu
- Institute of Pharmacy and Pharmacology, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang, China
| | - Qun Zhou
- College of Pharmacy, Hunan University of Medicine, Huaihua, China
| | - Zhe Chen
- Institute of Pharmacy and Pharmacology, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang, China
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang, China
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18
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Lee S, Bao H, Ishikawa Z, Wang W, Lim HY. Cardiomyocyte Regulation of Systemic Lipid Metabolism by the Apolipoprotein B-Containing Lipoproteins in Drosophila. PLoS Genet 2017; 13:e1006555. [PMID: 28095410 PMCID: PMC5283750 DOI: 10.1371/journal.pgen.1006555] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 01/31/2017] [Accepted: 12/28/2016] [Indexed: 11/21/2022] Open
Abstract
The heart has emerged as an important organ in the regulation of systemic lipid homeostasis; however, the underlying mechanism remains poorly understood. Here, we show that Drosophila cardiomyocytes regulate systemic lipid metabolism by producing apolipoprotein B-containing lipoproteins (apoB-lipoproteins), essential lipid carriers that are so far known to be generated only in the fat body. In a Drosophila genetic screen, we discovered that when haplo-insufficient, microsomal triglyceride transfer protein (mtp), required for the biosynthesis of apoB-lipoproteins, suppressed the development of diet-induced obesity. Tissue-specific inhibition of Mtp revealed that whereas knockdown of mtp only in the fat body decreases systemic triglyceride (TG) content on normal food diet (NFD) as expected, knockdown of mtp only in the cardiomyocytes also equally decreases systemic TG content on NFD, suggesting that the cardiomyocyte- and fat body-derived apoB-lipoproteins serve similarly important roles in regulating whole-body lipid metabolism. Unexpectedly, on high fat diet (HFD), knockdown of mtp in the cardiomyocytes, but not in fat body, protects against the gain in systemic TG levels. We further showed that inhibition of the Drosophila apoB homologue, apolipophorin or apoLpp, another gene essential for apoB-lipoprotein biosynthesis, affects systemic TG levels similarly to that of Mtp inhibition in the cardiomyocytes on NFD or HFD. Finally, we determined that HFD differentially alters Mtp and apoLpp expression in the cardiomyocytes versus the fat body, culminating in higher Mtp and apoLpp levels in the cardiomyocytes than in fat body and possibly underlying the predominant role of cardiomyocyte-derived apoB-lipoproteins in lipid metabolic regulation. Our findings reveal a novel and significant function of heart-mediated apoB-lipoproteins in controlling lipid homeostasis. The heart is increasingly recognized to serve an important role in the regulation of whole-body lipid homeostasis; however, the underlying mechanisms remained poorly understood. Here, our study in Drosophila reveals that cardiomyocytes regulate systemic lipid metabolism by producing apolipoprotein B-containing lipoproteins (apoB-lipoproteins), essential lipid carriers that are so far known to be generated only in the fat body (insect liver and adipose tissue). We found that apoB-lipoproteins generated by the Drosophila cardiomyocytes serve an equally significant role as their fat body-derived counterparts in maintaining systemic lipid homeostasis on normal food diet. Importantly, on high fat diet (HFD), the cardiomyocyte-derived apoB-lipoproteins are the major determinants of whole-body lipid metabolism, a role which could be attributed to the HFD-induced up-regulation of apoB-lipoprotein biosynthesis genes in the cardiomyocytes and their down-regulation in the fat body. Taken together, our results reveal that apoB-lipoproteins are new players in mediating the heart control of lipid metabolism, and provide first evidence supporting the notion that HFD-induced differential regulation of apoB-lipoprotein biosynthesis genes could alter the input of different tissue-derived apoB-lipoproteins in systemic lipid metabolic control.
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Affiliation(s)
- Sunji Lee
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Hong Bao
- Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
| | - Zachary Ishikawa
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Weidong Wang
- Department of Medicine, Section of Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail: (WW); (HYL)
| | - Hui-Ying Lim
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, United States of America
- * E-mail: (WW); (HYL)
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19
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Suzuki T, Swift LL. Discovery of Novel Splice Variants and Regulatory Mechanisms for Microsomal Triglyceride Transfer Protein in Human Tissues. Sci Rep 2016; 6:27308. [PMID: 27256115 PMCID: PMC4891672 DOI: 10.1038/srep27308] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/16/2016] [Indexed: 11/16/2022] Open
Abstract
Microsomal triglyceride transfer protein (MTP) is a unique lipid transfer protein essential for the assembly of triglyceride-rich lipoproteins by the liver and intestine. Previous studies in mice identified a splice variant of MTP with an alternate first exon. Splice variants of human MTP have not been reported. Using PCR approaches we have identified two splice variants in human tissues, which we have named MTP-B and MTP-C. MTP-B has a unique first exon (Ex1B) located 10.5 kb upstream of the first exon (Ex1A) for canonical MTP (MTP-A); MTP-C contains both first exons for MTP-A and MTP-B. MTP-B was found in a number of tissues, whereas MTP-C was prominent in brain and testis. MTP-B does not encode a protein; MTP-C encodes the same protein encoded by MTP-A, although MTP-C translation is strongly inhibited by regulatory elements within its 5′-UTR. Using luciferase assays, we demonstrate that the promoter region upstream of exon 1B is quite adequate to drive expression of MTP. We conclude that alternate splicing plays a key role in regulating cellular MTP levels by introducing distinct promoter regions and unique 5′-UTRs, which contain elements that alter translation efficiency, enabling the cell to optimize MTP activity.
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Affiliation(s)
- Takashi Suzuki
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Larry L Swift
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Research Service, Veterans Affairs, Tennessee Valley Health Care System, Nashville, TN, USA
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20
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Schmidinger B, Weijler AM, Schneider WJ, Hermann M. Hepatosteatosis and estrogen increase apolipoprotein O production in the chicken. Biochimie 2016; 127:37-43. [PMID: 27126072 DOI: 10.1016/j.biochi.2016.04.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
Apolipoprotein O (ApoO) is a recently discovered plasma apolipoprotein that may also play a role in the mitochondrial inner membrane. Possibly due to this complexity, its physiological functions have not been elucidated yet. To gain insight from a non-mammalian experimental system, we have investigated the regulation of ApoO levels in an alternative, well-suited model for studies on lipid metabolism, the chicken. qPCR using specific primer pairs and Western blot analysis with our rabbit anti-chicken ApoO antiserum demonstrated ApoO in the liver of chickens fed a control or a fat-enriched diet, as well as in 2 chicken hepatoma cell lines, LMH cells and the estrogen-responsive LMH-2A cells, under conditions of lipid loading by incubation with BSA-complexed oleic acid. Induced triglyceride accumulation in both the liver and the hepatic cells was associated with significantly increased levels of ApoO mRNA and protein. Furthermore, upon treatment for 24 h with estrogen of the estrogen receptor-expressing LMH-2A cells, quantitative analysis of ApoO transcripts and Western blotting revealed increases of ApoO expression. Finally, upon a single administration of estrogen to roosters that leads to hyperlipidemia, higher hepatic levels of both ApoO transcript and protein were observed within 24 h. Based on these data, we propose that hepatic expression of ApoO is tightly linked not only to diet-induced hepatosteatosis, but also to increased lipoprotein-production induced by, e.g., hormones. The findings support a role of ApoO as an effector of compromised mitochondrial function that likely accompanies the onset of non-alcoholic fatty liver disease.
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Affiliation(s)
- Barbara Schmidinger
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Anna M Weijler
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Wolfgang J Schneider
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Marcela Hermann
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria.
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21
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Identification of a Novel Transcript and Regulatory Mechanism for Microsomal Triglyceride Transfer Protein. PLoS One 2016; 11:e0147252. [PMID: 26771188 PMCID: PMC4714884 DOI: 10.1371/journal.pone.0147252] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/03/2016] [Indexed: 12/19/2022] Open
Abstract
Microsomal triglyceride transfer protein (MTP) is essential for the assembly of triglyceride-rich apolipoprotein B-containing lipoproteins. Previous studies in our laboratory identified a novel splice variant of MTP in mice that we named MTP-B. MTP-B has a unique first exon (1B) located 2.7 kB upstream of the first exon (1A) for canonical MTP (MTP-A). The two mature isoforms, though nearly identical in sequence and function, have different tissue expression patterns. In this study we report the identification of a second MTP splice variant (MTP-C), which contains both exons 1B and 1A. MTP-C is expressed in all the tissues we tested. In cells transfected with MTP-C, protein expression was less than 15% of that found when the cells were transfected with MTP-A or MTP-B. In silico analysis of the 5’-UTR of MTP-C revealed seven ATGs upstream of the start site for MTP-A, which is the only viable start site in frame with the main coding sequence. One of those ATGs was located in the 5’-UTR for MTP-A. We generated reporter constructs in which the 5’-UTRs of MTP-A or MTP-C were inserted between an SV40 promoter and the coding sequence of the luciferase gene and transfected these constructs into HEK 293 cells. Luciferase activity was significantly reduced by the MTP-C 5’-UTR, but not by the MTP-A 5’-UTR. We conclude that alternative splicing plays a key role in regulating MTP expression by introducing unique 5’-UTRs, which contain elements that alter translation efficiency, enabling the cell to optimize MTP levels and activity.
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22
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Li JY, Zhang DD, Jiang GZ, Li XF, Zhang CN, Zhou M, Liu WB, Xu WN. Cloning and characterization of microsomal triglyceride transfer protein gene and its potential connection with peroxisome proliferator-activated receptor (PPAR) in blunt snout bream (Megalobrama amblycephala). Comp Biochem Physiol B Biochem Mol Biol 2015. [PMID: 26210738 DOI: 10.1016/j.cbpb.2015.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Microsomal triglyceride transfer protein (MTTP), a major intracellular protein capable of transferring neutral lipids, plays a pivotal role in the assembly and secretion of apolipoprotein B-containing lipoproteins. In this study, MTTP cDNA was firstly cloned from the liver of blunt snout bream (Megalobrama amblycephala), the full-length cDNA covered 3457-bp with an open reading frame of 2661-bp, which encodes 886 amino acids, including a putative signal peptide of 24 amino acids long. After the feeding trial, a graded tissue-specific expression pattern of MTTP was observed and high expression abundance in the liver and intestine indicated its major function in lipid transport in this fish species. In addition, expression of genes encoding MTTP as well as peroxisome proliferator-activated receptor (PPAR), which are transcription factors and serve as key regulators in lipid homoeostasis, was all affected by dietary lipid and choline supplementations. Elevated dietary lipid levels significantly increased the liver, intestinal and muscle MTTP mRNA abundance. Additionally, the down-regulation of MTTP expression in the liver and muscle was observed when fish were fed with inadequate choline supplementation in high-fat diet, yet up-regulated as supplementing extra choline in diet. Expressions of PPARα and PPARβ in the liver and muscle showed similar trend of MTTP expression. The results suggested the potential connection of MTTP and PPAR in response to different dietary nutritional factors. Furthermore, extra choline supplementations could promote lipid transfer and enhance fatty acid oxidation, which indicated a molecular mechanism of choline on diminishing fat accumulation in blunt snout bream.
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Affiliation(s)
- Jun-Yi Li
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China
| | - Ding-Dong Zhang
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China
| | - Guang-Zhen Jiang
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China
| | - Xiang-Fei Li
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China
| | - Chun-Nuan Zhang
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China
| | - Man Zhou
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China
| | - Wen-Bin Liu
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China.
| | - Wei-Na Xu
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China.
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23
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Lénárt N, Walter FR, Bocsik A, Sántha P, Tóth ME, Harazin A, Tóth AE, Vizler C, Török Z, Pilbat AM, Vígh L, Puskás LG, Sántha M, Deli MA. Cultured cells of the blood-brain barrier from apolipoprotein B-100 transgenic mice: effects of oxidized low-density lipoprotein treatment. Fluids Barriers CNS 2015; 12:17. [PMID: 26184769 PMCID: PMC4504453 DOI: 10.1186/s12987-015-0013-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 07/01/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The apolipoprotein B-100 (ApoB-100) transgenic mouse line is a model of human atherosclerosis. Latest findings suggest the importance of ApoB-100 in the development of neurodegenerative diseases and microvascular/perivascular localization of ApoB-100 protein was demonstrated in the cerebral cortex of ApoB-100 transgenic mice. The aim of the study was to characterize cultured brain endothelial cells, pericytes and glial cells from wild-type and ApoB-100 transgenic mice and to study the effect of oxidized low-density lipoprotein (oxLDL) on these cells. METHODS Morphology of cells isolated from brains of wild type and ApoB-100 transgenic mice was characterized by immunohistochemistry and the intensity of immunolabeling was quantified by image analysis. Toxicity of oxLDL treatment was monitored by real-time impedance measurement and lactate dehydrogenase release. Reactive oxygen species and nitric oxide production, barrier permeability in triple co-culture blood-brain barrier model and membrane fluidity were also determined after low-density lipoprotein (LDL) or oxLDL treatment. RESULTS The presence of ApoB-100 was confirmed in brain endothelial cells, while no morphological change was observed between wild type and transgenic cells. Oxidized but not native LDL exerted dose-dependent toxicity in all three cell types, induced barrier dysfunction and increased reactive oxygen species (ROS) production in both genotypes. A partial protection from oxLDL toxicity was seen in brain endothelial and glial cells from ApoB-100 transgenic mice. Increased membrane rigidity was measured in brain endothelial cells from ApoB-100 transgenic mice and in LDL or oxLDL treated wild type cells. CONCLUSION The morphological and functional properties of cultured brain endothelial cells, pericytes and glial cells from ApoB-100 transgenic mice were characterized and compared to wild type cells for the first time. The membrane fluidity changes in ApoB-100 transgenic cells related to brain microvasculature indicate alterations in lipid composition which may be linked to the partial protection against oxLDL toxicity.
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Affiliation(s)
- Nikolett Lénárt
- Laboratory of Animal Genetics and Molecular Neurobiology, Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6720, Szeged, Hungary. .,Laboratory of Neuroimmunology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
| | - Fruzsina R Walter
- Biological Barriers Research Group, Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Alexandra Bocsik
- Biological Barriers Research Group, Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Petra Sántha
- Biological Barriers Research Group, Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Melinda E Tóth
- Laboratory of Animal Genetics and Molecular Neurobiology, Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6720, Szeged, Hungary.
| | - András Harazin
- Biological Barriers Research Group, Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Andrea E Tóth
- Biological Barriers Research Group, Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Csaba Vizler
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Zsolt Török
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Ana-Maria Pilbat
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - László Vígh
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - László G Puskás
- Laboratory of Functional Genomics, Laboratories of Core Facilities, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Miklós Sántha
- Laboratory of Animal Genetics and Molecular Neurobiology, Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6720, Szeged, Hungary.
| | - Mária A Deli
- Biological Barriers Research Group, Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
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Afolabi OK, Wusu AD, Ogunrinola OO, Abam EO, Babayemi DO, Dosumu OA, Onunkwor OB, Balogun EA, Odukoya OO, Ademuyiwa O. Arsenic-induced dyslipidemia in male albino rats: comparison between trivalent and pentavalent inorganic arsenic in drinking water. BMC Pharmacol Toxicol 2015; 16:15. [PMID: 26044777 PMCID: PMC4455335 DOI: 10.1186/s40360-015-0015-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2015] [Indexed: 01/05/2023] Open
Abstract
Background Recent epidemiological evidences indicate close association between inorganic arsenic exposure via drinking water and cardiovascular diseases. However, the exact mechanism of this arsenic-mediated increase in cardiovascular risk factors remains enigmatic. Methods In order to investigate the effects of inorganic arsenic exposure on lipid metabolism, male albino rats were exposed to 50, 100 and 150 ppm arsenic as sodium arsenite and 100, 150 and 200 ppm arsenic as sodium arsenate respectively in their drinking water for 12 weeks. Results Dyslipidemia induced by the two arsenicals exhibited different patterns. Hypocholesterolemia characterised the effect of arsenite at all the doses, but arsenate induced hypercholesterolemia at the 150 ppm As dose. Hypertriglyceridemia was the hallmark of arsenate effect whereas plasma free fatty acids (FFAs) was increased by the two arsenicals. Reverse cholesterol transport was inhibited by the two arsenicals as evidenced by decreased HDL cholesterol concentrations whereas hepatic cholesterol was increased by arsenite (100 ppm As), but decreased by arsenite (150 ppm As) and arsenate (100 ppm As) respectively. Brain cholesterol and triglyceride were decreased by the two arsenicals; arsenate decreased the renal content of cholesterol, but increased renal content of triglyceride. Arsenite, on the other hand, increased the renal contents of the two lipids. The two arsenicals induced phospholipidosis in the spleen. Arsenite (150 ppm As) and arsenate (100 ppm As) inhibited hepatic HMG CoA reductase. At other doses of the two arsenicals, hepatic activity of the enzyme was up-regulated. The two arsenicals however up-regulated the activity of the brain enzyme. We observed positive associations between tissue arsenic levels and plasma FFA and negative associations between tissue arsenic levels and HDL cholesterol. Conclusion Our findings indicate that even though sub-chronic exposure to arsenite and arsenate through drinking water produced different patterns of dyslipidemia, our study identified two common denominators of dyslipidemia namely: inhibition of reverse cholesterol transport and increase in plasma FFA. These two denominators (in addition to other individual perturbations of lipid metabolism induced by each arsenical), suggest that in contrast to strengthening a dose-dependent effect phenomenon, the two forms of inorganic arsenic induced lipotoxic and non-lipotoxic dyslipidemia at “low” or “medium” doses and these might be responsible for the cardiovascular and other disease endpoints of inorganic arsenic exposure through drinking water.
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Affiliation(s)
- Olusegun K Afolabi
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria. .,Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomosho, Nigeria.
| | - Adedoja D Wusu
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria. .,Department of Biochemistry, Lagos State University, Ojoo, Lagos, Nigeria.
| | - Olabisi O Ogunrinola
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria. .,Department of Biochemistry, Lagos State University, Ojoo, Lagos, Nigeria.
| | - Esther O Abam
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria. .,Biochemistry Unit, Department of Chemical Sciences, Bells University of Technology, Ota, Nigeria.
| | - David O Babayemi
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria.
| | - Oluwatosin A Dosumu
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria.
| | - Okechukwu B Onunkwor
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria.
| | - Elizabeth A Balogun
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria. .,Department of Biochemistry, University of Ilorin, Ilorin, Nigeria.
| | - Olusegun O Odukoya
- Department of Chemistry, Federal University of Agriculture, Abeokuta, Nigeria.
| | - Oladipo Ademuyiwa
- Department of Biochemistry, Federal University of Agriculture, Abeokuta, Nigeria.
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25
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Otis JP, Zeituni EM, Thierer JH, Anderson JL, Brown AC, Boehm ED, Cerchione DM, Ceasrine AM, Avraham-Davidi I, Tempelhof H, Yaniv K, Farber SA. Zebrafish as a model for apolipoprotein biology: comprehensive expression analysis and a role for ApoA-IV in regulating food intake. Dis Model Mech 2015; 8:295-309. [PMID: 25633982 PMCID: PMC4348566 DOI: 10.1242/dmm.018754] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Improved understanding of lipoproteins, particles that transport lipids throughout the circulation, is vital to developing new treatments for the dyslipidemias associated with metabolic syndrome. Apolipoproteins are a key component of lipoproteins. Apolipoproteins are proteins that structure lipoproteins and regulate lipid metabolism through control of cellular lipid exchange. Constraints of cell culture and mouse models mean that there is a need for a complementary model that can replicate the complex in vivo milieu that regulates apolipoprotein and lipoprotein biology. Here, we further establish the utility of the genetically tractable and optically clear larval zebrafish as a model of apolipoprotein biology. Gene ancestry analyses were implemented to determine the closest human orthologs of the zebrafish apolipoprotein A-I (apoA-I), apoB, apoE and apoA-IV genes and therefore ensure that they have been correctly named. Their expression patterns throughout development were also analyzed, by whole-mount mRNA in situ hybridization (ISH). The ISH results emphasized the importance of apolipoproteins in transporting yolk and dietary lipids: mRNA expression of all apolipoproteins was observed in the yolk syncytial layer, and intestinal and liver expression was observed from 4-6 days post-fertilization (dpf). Furthermore, real-time PCR confirmed that transcription of three of the four zebrafish apoA-IV genes was increased 4 hours after the onset of a 1-hour high-fat feed. Therefore, we tested the hypothesis that zebrafish ApoA-IV performs a conserved role to that in rat in the regulation of food intake by transiently overexpressing ApoA-IVb.1 in transgenic larvae and quantifying ingestion of co-fed fluorescently labeled fatty acid during a high-fat meal as an indicator of food intake. Indeed, ApoA-IVb.1 overexpression decreased food intake by approximately one-third. This study comprehensively describes the expression and function of eleven zebrafish apolipoproteins and serves as a springboard for future investigations to elucidate their roles in development and disease in the larval zebrafish model.
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Affiliation(s)
- Jessica P Otis
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Erin M Zeituni
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - James H Thierer
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Jennifer L Anderson
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Alexandria C Brown
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Erica D Boehm
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Derek M Cerchione
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Alexis M Ceasrine
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Inbal Avraham-Davidi
- Weizmann Institute of Science, Department of Biological Regulation, Rehovot 7610001, Israel
| | - Hanoch Tempelhof
- Weizmann Institute of Science, Department of Biological Regulation, Rehovot 7610001, Israel
| | - Karina Yaniv
- Weizmann Institute of Science, Department of Biological Regulation, Rehovot 7610001, Israel
| | - Steven A Farber
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
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Levy E. Insights from human congenital disorders of intestinal lipid metabolism. J Lipid Res 2014; 56:945-62. [PMID: 25387865 DOI: 10.1194/jlr.r052415] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Indexed: 12/24/2022] Open
Abstract
The intestine must challenge the profuse daily flux of dietary fat that serves as a vital source of energy and as an essential component of cell membranes. The fat absorption process takes place in a series of orderly and interrelated steps, including the uptake and translocation of lipolytic products from the brush border membrane to the endoplasmic reticulum, lipid esterification, Apo synthesis, and ultimately the packaging of lipid and Apo components into chylomicrons (CMs). Deciphering inherited disorders of intracellular CM elaboration afforded new insight into the key functions of crucial intracellular proteins, such as Apo B, microsomal TG transfer protein, and Sar1b GTPase, the defects of which lead to hypobetalipoproteinemia, abetalipoproteinemia, and CM retention disease, respectively. These "experiments of nature" are characterized by fat malabsorption, steatorrhea, failure to thrive, low plasma levels of TGs and cholesterol, and deficiency of liposoluble vitamins and essential FAs. After summarizing and discussing the functions and regulation of these proteins for reader's comprehension, the current review focuses on their specific roles in malabsorptions and dyslipidemia-related intestinal fat hyperabsorption while dissecting the spectrum of clinical manifestations and managements. The influence of newly discovered proteins (proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 protein) on fat absorption has also been provided. Finally, it is stressed how the overexpression or polymorphism status of the critical intracellular proteins promotes dyslipidemia and cardiometabolic disorders.
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Affiliation(s)
- Emile Levy
- Research Centre, CHU Sainte-Justine and Department of Nutrition, Université de Montréal, Montreal, Quebec H3T 1C5, Canada
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27
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Fujihara M, Cano M, Handa JT. Mice that produce ApoB100 lipoproteins in the RPE do not develop drusen yet are still a valuable experimental system. Invest Ophthalmol Vis Sci 2014; 55:7285-95. [PMID: 25316721 DOI: 10.1167/iovs.14-15195] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Mice typically produce apolipoprotein B (apoB)-48 and not apoB100. Apolipoprotein B100 accumulates in Bruch's membrane prior to basal deposit and drusen formation during the onset of AMD, raising the possibility that they are a trigger for these Bruch's membrane alterations. The purpose herein, was to determine whether mice that predominantly produce apoB100 develop features of AMD. METHODS The eyes of mice that produce apoB100 were examined for apoB100 synthesis, cholesteryl esterase/filipin labeling for cholesteryl esters, and transmission electron microscopy for lipid particles and phenotype. RESULTS Apolipoprotein B100 was abundant in the RPE-choroid of apoB100, but not wild-type mice by Western blot analysis. The apolipoprotein B100,(35)S-radiolabeled and immunoprecipitated from RPE explants, confirmed that apoB100 was synthesized by RPE. Apolipoprotein B100, but not control mice, had cholesteryl esters and lipid particles in Bruch's membrane. Immunoreactivity of ApoB100 was present in the RPE and Bruch's membrane, but not choroidal endothelium of apoB100 mice. Ultrastructural changes were consistent with aging, but not AMD when aged up to 18 months. The induction of advanced glycation end products to alter Bruch's membrane, did not promote basal linear deposit or drusen formation. CONCLUSIONS Mice that produce apoB100 in the RPE and liver secrete lipoproteins into Bruch's membrane, but not to the extent that distinct features of AMD develop, which suggests that either additional lipoprotein accumulation or additional factors are necessary to initiate their formation.
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Affiliation(s)
- Masashi Fujihara
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Marisol Cano
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - James T Handa
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
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van Montfoort AP, Plösch T, Hoek A, Tietge UJ. Impact of maternal cholesterol metabolism on ovarian follicle development and fertility. J Reprod Immunol 2014; 104-105:32-6. [DOI: 10.1016/j.jri.2014.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 04/02/2014] [Accepted: 04/16/2014] [Indexed: 01/24/2023]
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Mora S, Akinkuolie AO, Sandhu RK, Conen D, Albert CM. Paradoxical association of lipoprotein measures with incident atrial fibrillation. Circ Arrhythm Electrophysiol 2014; 7:612-9. [PMID: 24860180 PMCID: PMC4591535 DOI: 10.1161/circep.113.001378] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 04/22/2014] [Indexed: 11/16/2022]
Abstract
BACKGROUND Low-density lipoprotein (LDL) cholesterol is a strong risk factor for atherosclerosis but has an inverse association with atrial fibrillation (AF). We aimed to provide insight into the paradoxical association of LDL cholesterol with AF by evaluating the relationship of various lipoprotein measures and incident AF. METHODS AND RESULTS We prospectively evaluated lipoprotein measures among 23 738 healthy middle-aged and older women (median follow-up 16.4 years; N=795 incident AF events). Baseline LDL cholesterol was directly measured, lipoprotein particle concentrations and size were measured by nuclear magnetic resonance spectroscopy, and apolipoproteins were measured by immunoassay. Cox regression models were adjusted for age, AF risk factors, inflammatory, and dysglycemic biomarkers. After multivariable adjustment, inverse associations with AF were observed (hazard ratio, 95% confidence interval for top versus bottom quintile, P value) for LDL cholesterol (0.72, 0.56-0.92, P=0.009), the total number of LDL particles (0.77, 0.60-0.99, P=0.045), and very-low-density lipoprotein particles (0.78, 0.61-0.99, P=0.04), which was driven by the number of cholesterol-poor small LDL (0.78, 0.61-1.00, P=0.05) and small very-low-density lipoprotein particles (0.78, 0.62-0.99, P=0.04). By contrast, the larger cholesterol-rich LDL particles and all high-density lipoprotein measures were not associated with AF in multivariable models. Adjustment for inflammatory and dysglycemic biomarkers had minimal impact on these associations. CONCLUSIONS In this prospective study, the inverse association between LDL cholesterol and AF extended to several other atherogenic lipoproteins, and these associations are unlikely to be mediated by direct cholesterol effects. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov; Unique Identifier: NCT00000479.
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Affiliation(s)
- Samia Mora
- From the Division of Preventive Medicine (S.M., A.O.A., C.M.A.) and Division of Cardiovascular Medicine (S.M., C.M.A.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada (R.K.S.); and Department of Medicine, University Hospital, Basel, Switzerland (D.C.).
| | - Akintunde O Akinkuolie
- From the Division of Preventive Medicine (S.M., A.O.A., C.M.A.) and Division of Cardiovascular Medicine (S.M., C.M.A.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada (R.K.S.); and Department of Medicine, University Hospital, Basel, Switzerland (D.C.)
| | - Roopinder K Sandhu
- From the Division of Preventive Medicine (S.M., A.O.A., C.M.A.) and Division of Cardiovascular Medicine (S.M., C.M.A.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada (R.K.S.); and Department of Medicine, University Hospital, Basel, Switzerland (D.C.)
| | - David Conen
- From the Division of Preventive Medicine (S.M., A.O.A., C.M.A.) and Division of Cardiovascular Medicine (S.M., C.M.A.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada (R.K.S.); and Department of Medicine, University Hospital, Basel, Switzerland (D.C.)
| | - Christine M Albert
- From the Division of Preventive Medicine (S.M., A.O.A., C.M.A.) and Division of Cardiovascular Medicine (S.M., C.M.A.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada (R.K.S.); and Department of Medicine, University Hospital, Basel, Switzerland (D.C.)
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30
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Stefanutti C. Targeting MTP for the treatment of homozygous familial hypercholesterolemia. ACTA ACUST UNITED AC 2014. [DOI: 10.2217/clp.14.17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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31
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Winter Y, Sankowski R, Back T. Genetic determinants of obesity and related vascular diseases. VITAMINS AND HORMONES 2013; 91:29-48. [PMID: 23374711 DOI: 10.1016/b978-0-12-407766-9.00002-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Obesity is one of the major risk factors of vascular diseases, and its prevalence is increasing worldwide. In the past decade, progress has been made in the understanding of genetic determinants of obesity and obesity-associated diseases. Genome-wide association studies identified a number of genetic variants associated with obesity. In addition to common variants, FTO and MC4R, new loci, such as TMEM18, KCTD15, GNPDA2, SH2B1, MTCH2, and NEGR1 have been detected. In the past years, abdominal obesity has been shown to be a more important vascular risk factor than the body mass index. In the context of vascular risk assessment, identification of genetic polymorphisms associated with accumulation of visceral fat is of special importance. Some polymorphisms associated with abdominal obesity, such as variants of gene encoding microsomal triglyceride transfer protein, have been already discovered. In this chapter, we provide a review of genetic determinants of obesity and discuss their role in obesity-related vascular diseases.
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Affiliation(s)
- Yaroslav Winter
- Department of Neurology, Philipps-University, Marburg Germany
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32
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Myocardial triacylglycerol metabolism. J Mol Cell Cardiol 2012; 55:101-10. [PMID: 22789525 DOI: 10.1016/j.yjmcc.2012.06.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 06/22/2012] [Accepted: 06/28/2012] [Indexed: 11/22/2022]
Abstract
Myocardial triacylglycerol (TAG) constitutes a highly dynamic fatty acid (FA) storage pool that can be used for an energy reserve in the cardiomyocyte. However, derangements in myocardial TAG metabolism and accumulation are commonly associated with cardiac disease, suggesting an important role of intramyocardial TAG turnover in the regulation of cardiac function. In cardiomyocytes, TAG is synthesized by acyltransferases and phosphatases at the sarcoplasmic reticulum and mitochondrial membrane and then packaged into cytosolic lipid droplets for temporary storage or into lipoproteins for secretion. A complex interplay among lipases, lipase regulatory proteins, and lipid droplet scaffold proteins leads to the controlled release of FAs from the cardiac TAG pool for subsequent mitochondrial β-oxidation and energy production. With the identification and characterization of proteins involved in myocardial TAG metabolism as well as the identification of the importance of cardiac TAG turnover, it is now evident that adequate regulation of myocardial TAG metabolism is critical for both cardiac energy metabolism and function. In this article, we review the current understanding of myocardial TAG metabolism and discuss the potential role of myocardial TAG turnover in cardiac health and disease. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism".
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Abstract
The heart has both the greatest caloric needs and the most robust oxidation of fatty acids (FAs). Under pathological conditions such as obesity and type 2 diabetes, cardiac uptake and oxidation are not balanced and hearts accumulate lipid potentially leading to cardiac lipotoxicity. We will first review the pathways utilized by the heart to acquire FAs from the circulation and to store triglyceride intracellularly. Then we will describe mouse models in which excess lipid accumulation causes heart dysfunction and experiments performed to alleviate this toxicity. Finally, the known relationships between heart lipid metabolism and dysfunction in humans will be summarized.
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Affiliation(s)
- Ira J Goldberg
- Department of Medicine, Columbia University, New York, NY 10032, USA.
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Hussain MM, Rava P, Walsh M, Rana M, Iqbal J. Multiple functions of microsomal triglyceride transfer protein. Nutr Metab (Lond) 2012; 9:14. [PMID: 22353470 PMCID: PMC3337244 DOI: 10.1186/1743-7075-9-14] [Citation(s) in RCA: 175] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/21/2012] [Indexed: 02/08/2023] Open
Abstract
Microsomal triglyceride transfer protein (MTP) was first identified as a major cellular protein capable of transferring neutral lipids between membrane vesicles. Its role as an essential chaperone for the biosynthesis of apolipoprotein B (apoB)-containing triglyceride-rich lipoproteins was established after the realization that abetalipoproteinemia patients carry mutations in the MTTP gene resulting in the loss of its lipid transfer activity. Now it is known that it also plays a role in the biosynthesis of CD1, glycolipid presenting molecules, as well as in the regulation of cholesterol ester biosynthesis. In this review, we will provide a historical perspective about the identification, purification and characterization of MTP, describe methods used to measure its lipid transfer activity, and discuss tissue expression and function. Finally, we will review the role MTP plays in the assembly of apoB-lipoprotein, the regulation of cholesterol ester synthesis, biosynthesis of CD1 proteins and propagation of hepatitis C virus. We will also provide a brief overview about the clinical potentials of MTP inhibition.
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Affiliation(s)
- M Mahmood Hussain
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Paul Rava
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Meghan Walsh
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Muhammad Rana
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Jahangir Iqbal
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
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Råmunddal T, Lindbom M, Täng MS, Shao Y, Borén J, Omerovic E. Overexpression of apolipoprotein B attenuates pathologic cardiac remodeling and hypertrophy in response to catecholamines and after myocardial infarction in mice. Scandinavian Journal of Clinical and Laboratory Investigation 2012; 72:230-6. [DOI: 10.3109/00365513.2012.654506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Truls Råmunddal
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg,
Gothenburg, Sweden
- Division of Cardiology, Sahlgrenska University Hospital,
Gothenburg, Sweden
| | - Malin Lindbom
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg,
Gothenburg, Sweden
| | - Margareta Scharin Täng
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg,
Gothenburg, Sweden
| | - Yangzhen Shao
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg,
Gothenburg, Sweden
| | - Jan Borén
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg,
Gothenburg, Sweden
| | - Elmir Omerovic
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg,
Gothenburg, Sweden
- Division of Cardiology, Sahlgrenska University Hospital,
Gothenburg, Sweden
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Redfors B, Shao Y, Råmunddal T, Lindbom M, Täng MS, Stillemark-Billton P, Boren J, Omerovic E. Effects of doxorubicin on myocardial expression of apolipoprotein-B. SCAND CARDIOVASC J 2012; 46:93-8. [PMID: 22263831 DOI: 10.3109/14017431.2012.653825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Doxorubicin (DOX) is an effective antitumour agent against a variety of human malignancies but is associated with deleterious side effects, including myocardial damage and heart failure. Myocardial apoB-containing lipoprotein (apoB) is upregulated post myocardial infarction and has been shown to be cardioprotective in this setting by unloading excessive lipid. The aim of this study was to investigate whether apoB expression is increased also in DOX-induced heart failure and whether apoB overexpression protects the heart in DOX-induced myocardial injury. DESIGN Cardiac function and energy metabolism was studied in mice and rats 24 hours after intraperitoneally administered DOX. RESULTS We found that the content of apoB was decreased in rat myocardium 24 hours after DOX injection. In contrast, apoB content was increased in the infarcted myocardium of rats 24 hours post ischemia-reperfusion. Moreover, transgenic mice overexpressing apoB had better cardiac function and lower intracellular lipid accumulation compared to wild type mice 24 hours post DOX. CONCLUSIONS Our findings indicate that depression of the myocardial apoB system may contribute to DOX-induced cardiac injury and that overexpression of apoB is protective, not only in ischemically damaged myocardium, but also in DOX-induced heart failure.
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Affiliation(s)
- Bjorn Redfors
- The Wallenberg laboratory at Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden.
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Redfors B, Shao Y, Råmunddal T, Lindbom M, Täng MS, Stillemark-Billton P, Boren J, Omerovic E. Effects of doxorubicin on myocardial expression of apolipoprotein-B. SCAND CARDIOVASC J 2011. [DOI: 10.3109/14017431.2011.653825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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38
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Siqueira ERF, Oliveira CPMS, Correa-Giannella ML, Stefano JT, Cavaleiro AM, Fortes MAHZ, Muniz MTC, Silva FS, Pereira LMMB, Carrilho FJ. MTP -493G/T gene polymorphism is associated with steatosis in hepatitis C-infected patients. Braz J Med Biol Res 2011; 45:72-7. [PMID: 22147193 PMCID: PMC3854139 DOI: 10.1590/s0100-879x2011007500160] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 11/25/2011] [Indexed: 12/17/2022] Open
Abstract
The reduction of hepatic microsomal transfer protein (MTP) activity results in fatty liver, worsening hepatic steatosis and fibrosis in chronic hepatitis C (CHC). The G allele of the MTP gene promoter, -493G/T, has been associated with lower transcriptional activity than the T allele. We investigated this association with metabolic and histological variables in patients with CHC. A total of 174 untreated patients with CHC were genotyped for MTP -493G/T by direct sequencing using PCR. All patients were negative for markers of Wilson's disease, hemochromatosis and autoimmune diseases and had current and past daily alcohol intake lower than 100 g/week. The sample distribution was in Hardy-Weinberg equilibrium. Among subjects with genotype 1, 56.8% of the patients with fibrosis grade 3+4 presented at least one G allele versus 34.3% of the patients with fibrosis grade 1+2 (OR = 1.8; 95%CI = 1.3-2.3). Logistic regression analysis with steatosis as the dependent variable identified genotypes GG+GT as independent protective factors against steatosis (OR = 0.4, 95%CI = 0.2-0.8; P = 0.01). The results suggest that the presence of the G allele of MTP -493G/T associated with lower hepatic MTP expression protects against steatosis in our CHC patients.
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Affiliation(s)
- E R F Siqueira
- Departamento de Gastroenterologia, Universidade de São Paulo, São Paulo, SP, Brasil
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Hentati F, El-Euch G, Bouhlal Y, Amouri R. Ataxia with vitamin E deficiency and abetalipoproteinemia. HANDBOOK OF CLINICAL NEUROLOGY 2011; 103:295-305. [PMID: 21827896 DOI: 10.1016/b978-0-444-51892-7.00018-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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40
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Calandra S, Tarugi P, Speedy HE, Dean AF, Bertolini S, Shoulders CC. Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk. J Lipid Res 2011; 52:1885-926. [PMID: 21862702 DOI: 10.1194/jlr.r017855] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means.
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Affiliation(s)
- Sebastiano Calandra
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy.
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41
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Lipids, lipoproteins, and age-related macular degeneration. J Lipids 2011; 2011:802059. [PMID: 21822496 PMCID: PMC3147126 DOI: 10.1155/2011/802059] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 04/14/2011] [Accepted: 05/09/2011] [Indexed: 01/31/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly. While excellent treatment has emerged for neovascular disease, treatment for early AMD is lacking due to an incomplete understanding of the early molecular events. A prominent age-related change is the accumulation of neutral lipid in normal Bruch's membrane (BrM) throughout adulthood and also disease-related BrM accumulations called basal deposits and drusen. AMD lesion formation has thus been conceptualized as sharing mechanisms with atherosclerotic plaque formation, where low-density lipoprotein (LDL) retention within the arterial wall initiates a cascade of pathologic events. However, we do not yet understand how lipoproteins contribute to AMD. This paper explores how systemic and local production of lipoproteins might contribute to the pathogenesis of AMD.
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Hussain MM, Nijstad N, Franceschini L. Regulation of microsomal triglyceride transfer protein. ACTA ACUST UNITED AC 2011; 6:293-303. [PMID: 21808658 DOI: 10.2217/clp.11.21] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Microsomal triglyceride transfer protein (MTP) facilitates the transport of dietary and endogenous fat by the intestine and liver by assisting in the assembly and secretion of triglyceride-rich apolipoprotein B-containing lipoproteins. Higher concentrations of apolipoprotein B lipoproteins predispose individuals to various cardiovascular and metabolic diseases such as atherosclerosis, diabetes, obesity and the metabolic syndrome. These can potentially be avoided by reducing MTP activity. In this article, we discuss regulation of MTP during development, cellular differentiation and diurnal variation. Furthermore, we focus on the regulation of MTP that occurs at transcriptional, post-transcriptional and post-translational levels. Transcriptional regulation of MTP depends on a few highly conserved cis-elements in the promoter. Several transcription factors that bind to these elements and either increase or decrease MTP expression have been identified. Additionally, MTP is regulated by macronutrients, hormones and other factors. This article will address the many ways in which MTP is regulated and advance the idea that reducing MTP levels, rather than its inhibition, might be an option to lower plasma lipids.
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Affiliation(s)
- M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, The State University of New York, Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA
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Almeida MEFD, Queiroz JHD, Costa NMB, Matta SLP. Lipídeos séricos e morfologia hepática de ratos alimentados com diferentes fontes lipídicas (óleo de soja, gordura de peixe e porco, margarina e manteiga). REV NUTR 2011. [DOI: 10.1590/s1415-52732011000100014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJETIVO: Analisar as alterações lipídicas séricas e morfológicas hepáticas de ratos alimentados com diferentes fontes lipídicas (óleo de soja, gordura de peixe e porco, margarina e manteiga). MÉTODOS: Os 50 ratos Wistars utilizados no estudo foram divididos em cinco grupos, que durante 28 dias receberam dietas semissintéticas com diferentes fontes lipídicas: óleo de soja, gordura de porco, manteiga, margarina e gordura de peixe. Foram avaliados os pesos corporais, o consumo alimentar e o coeficiente de eficiência alimentar; a atividade da lipase lipoproteica; as concentrações séricas de colesterol total e de lipoproteína de alta densidade - colesterol, triacilgliceróis e albumina, bem como a histologia dos tecidos hepático e cardíaco. RESULTADOS: O tipo de fonte lipídica não influenciou o consumo alimentar, o ganho de peso, o coeficiente de eficiência alimentar dos animais, nem a atividade da lipase lipoproteica, porém promoveu alterações nas concentrações séricas de colesterol total, lipoproteína de alta densidade - colesterol, triacilgliceróis e albumina. Todos os grupos apresentaram gotículas lipídicas nas paredes coronarianas e nos capilares cardíacos, sendo caracterizada como esteatose a deposição de gordura no fígado dos animais que receberam óleo de soja, gordura de peixe, de porco e manteiga. CONCLUSÃO: A fonte lipídica que apresentou os melhores resultados foi o óleo de soja, enquanto o consumo de gordura do peixe causou efeito sérico e tecidual semelhante ao encontrado para as outras fontes lipídicas (gordura de porco, manteiga e margarina), as quais podem contribuir para o surgimento e a progressão das doenças cardiovasculares.
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Peretti N, Sassolas A, Roy CC, Deslandres C, Charcosset M, Castagnetti J, Pugnet-Chardon L, Moulin P, Labarge S, Bouthillier L, Lachaux A, Levy E. Guidelines for the diagnosis and management of chylomicron retention disease based on a review of the literature and the experience of two centers. Orphanet J Rare Dis 2010; 5:24. [PMID: 20920215 PMCID: PMC2956717 DOI: 10.1186/1750-1172-5-24] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 09/29/2010] [Indexed: 02/06/2023] Open
Abstract
Familial hypocholesterolemia, namely abetalipoproteinemia, hypobetalipoproteinemia and chylomicron retention disease (CRD), are rare genetic diseases that cause malnutrition, failure to thrive, growth failure and vitamin E deficiency, as well as other complications. Recently, the gene implicated in CRD was identified. The diagnosis is often delayed because symptoms are nonspecific. Treatment and follow-up remain poorly defined. The aim of this paper is to provide guidelines for the diagnosis, treatment and follow-up of children with CRD based on a literature overview and two pediatric centers 'experience. The diagnosis is based on a history of chronic diarrhea with fat malabsorption and abnormal lipid profile. Upper endoscopy and histology reveal fat-laden enterocytes whereas vitamin E deficiency is invariably present. Creatine kinase (CK) is usually elevated and hepatic steatosis is common. Genotyping identifies the Sar1b gene mutation. Treatment should be aimed at preventing potential complications. Vomiting, diarrhea and abdominal distension improve on a low-long chain fat diet. Failure to thrive is one of the most common initial clinical findings. Neurological and ophthalmologic complications in CRD are less severe than in other types of familial hypocholesterolemia. However, the vitamin E deficiency status plays a pivotal role in preventing neurological complications. Essential fatty acid (EFA) deficiency is especially severe early in life. Recently, increased CK levels and cardiomyopathy have been described in addition to muscular manifestations. Poor mineralization and delayed bone maturation do occur. A moderate degree of macrovesicular steatosis is common, but no cases of steatohepatitis cirrhosis. Besides a low-long chain fat diet made up uniquely of polyunsaturated fatty acids, treatment includes fat-soluble vitamin supplements and large amounts of vitamin E. Despite fat malabsorption and the absence of postprandial chylomicrons, the oral route can prevent neurological complications even though serum levels of vitamin E remain chronically low. Dietary counseling is needed not only to monitor fat intake and improve symptoms, but also to maintain sufficient caloric and EFA intake. Despite a better understanding of the pathogenesis of CRD, the diagnosis and management of the disease remain a challenge for clinicians. The clinical guidelines proposed will helpfully lead to an earlier diagnosis and the prevention of complications.
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Affiliation(s)
- Noel Peretti
- Department of Nutrition, CHU Sainte-Justine Research Center, Université de Montréal, 3175, Ste-Catherine Road, Montreal, Quebec, H3T 1C5, Canada
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45
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Gautier T, Becker S, Drouineaud V, Ménétrier F, Sagot P, Nofer JR, von Otte S, Lagrost L, Masson D, Tietge UJF. Human luteinized granulosa cells secrete apoB100-containing lipoproteins. J Lipid Res 2010; 51:2245-52. [PMID: 20407020 DOI: 10.1194/jlr.m005181] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Thus far, liver, intestine, heart, and placenta have been shown to secrete apolipoprotein (apo)B-containing lipoproteins. In the present study, we first investigated lipoproteins in human follicular fluid (FF), surrounding developing oocytes within the ovary, as well as in corresponding plasma samples (n = 12). HDL cholesterol within FF correlated well with plasma HDL cholesterol (r = 0.80, P < 0.01), whereas VLDL cholesterol did not, indicating that VLDL in FF might originate directly from the granulosa cells producing FF. Primary human granulosa cells expressed apoB, microsomal triglyceride transfer protein, and apoE, but not the apoB-editing enzyme apobec-1. Using (3)H-leucine, we show that granulosa cells secrete apoB100-containing lipoproteins and that secretion can be stimulated by adding oleate to the medium (+83%). With electron microscopy, apoB-containing lipoproteins within the secretory pathway of human granulosa cells were directly visualized. Finally, we found a positive relationship between apoB levels in FF and improved fertility parameters in a population of 27 women undergoing in vitro fertilization. This study demonstrates that human granulosa cells assemble and secrete apoB100-containing lipoproteins, thereby identifying a novel cell type equipped with these properties. These results might have important implications for female infertility phenotypes as well as for the development of drugs targeting the VLDL production pathway.
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Affiliation(s)
- Thomas Gautier
- Faculté de Médecine, INSERM UMR866 Lipides, Nutrition, Cancer, Dijon, France
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46
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Aminoff A, Ledmyr H, Thulin P, Lundell K, Nunez L, Strandhagen E, Murphy C, Lidberg U, Westerbacka J, Franco-Cereceda A, Liska J, Nielsen LB, Gåfvels M, Mannila MN, Hamsten A, Yki-Järvinen H, Thelle D, Eriksson P, Borén J, Ehrenborg E. Allele-specific regulation of MTTP expression influences the risk of ischemic heart disease. J Lipid Res 2010; 51:103-11. [PMID: 19546343 DOI: 10.1194/jlr.m900195-jlr200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Promoter polymorphisms in microsomal triglyceride transfer protein (MTTP) have been associated with decreased plasma lipids but an increased risk for ischemic heart disease (IHD), indicating that MTTP influences the susceptibility for IHD independent of plasma lipids. The objective of this study was to characterize the functional promoter polymorphism in MTTP predisposing to IHD and its underlying mechanism. Use of pyrosequencing technology revealed that presence of the minor alleles of the promoter polymorphisms -493G>T and -164T>C result in lower transcription of MTTP in vivo in the heart, liver, and macrophages. In vitro experiments indicated that the minor -164C allele mediates the lower gene expression and that C/EBP binds to the polymorphic region in an allele-specific manner. Furthermore, homozygous carriers of the -164C were found to have increased risk for IHD as shown in a case-control study including a total of 544 IHD patients and 544 healthy control subjects. We concluded that carriers of the minor -164C allele have lower expression of MTTP in the heart, mediated at least partly by the transcription factor CCAAT/enhancer binding protein, and that reduced concentration of MTTP in the myocardium may contribute to IHD upon ischemic damage.
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Affiliation(s)
- Anna Aminoff
- Atherosclerosis Research Unit, Department of Medicine, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
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Krzystanek M, Pedersen TX, Bartels ED, Kjaehr J, Straarup EM, Nielsen LB. Expression of apolipoprotein B in the kidney attenuates renal lipid accumulation. J Biol Chem 2010; 285:10583-90. [PMID: 20103594 DOI: 10.1074/jbc.m109.078006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The ability to produce apolipoprotein (apo) B-containing lipoproteins enables hepatocytes, enterocytes, and cardiomyocytes to export triglycerides. In this study, we examined secretion of apoB-containing lipoproteins from mouse kidney and its putative impact on triglyceride accumulation in the tubular epithelium. Mouse kidney expressed both the apoB and microsomal triglyceride transfer protein genes, which permit lipoprotein formation. To examine de novo lipoprotein secretion, kidneys from human apoB-transgenic mice were minced and placed in medium with (35)S-amino acids. Upon sucrose gradient ultracentrifugation of the labeled medium, fractions were analyzed by apoB immunoprecipitation. (35)S-Labeled apoB100 was recovered in approximately 1.03-1.04 g/ml lipoproteins (i.e. similar to the density of plasma low density lipoproteins). Immunohistochemistry of kidney sections suggested that apoB mainly is produced by tubular epithelial cells. ApoB expression in the kidney cortex was reduced approximately 90% in vivo by treating wild type mice with apoB-antisense locked nucleic acid oligonucleotide. Inhibition of apoB expression increased fasting-induced triglyceride accumulation in the kidney cortex by 20-25% (p = 0.008). Cholesterol stores were unaffected. Treatment with control oligonucleotides with 1 or 4 mismatching base pairs affected neither the triglyceride nor the cholesterol content of the kidney cortex. The results suggest that mammalian kidney secretes apoB100-containing lipoproteins. One biological effect may be to dampen excess storage of triglycerides in proximal tubule cells.
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Affiliation(s)
- Marcin Krzystanek
- Department of Clinical Biochemistry, Rigshospitalet, DK-2100 Copenhagen
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48
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Suzuki J, Ueno M, Uno M, Hirose Y, Zenimaru Y, Takahashi S, Osuga JI, Ishibashi S, Takahashi M, Hirose M, Yamada M, Kraemer FB, Miyamori I. Effects of hormone-sensitive lipase disruption on cardiac energy metabolism in response to fasting and refeeding. Am J Physiol Endocrinol Metab 2009; 297:E1115-24. [PMID: 19706782 DOI: 10.1152/ajpendo.91031.2008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Increased fatty acid (FA) flux and intracellular lipid accumulation (steatosis) give rise to cardiac lipotoxicity in both pathological and physiological conditions. Since hormone-sensitive lipase (HSL) contributes to intracellular lipolysis in adipose tissue and heart, we investigated the impact of HSL disruption on cardiac energy metabolism in response to fasting and refeeding. HSL-knockout (KO) mice and wild-type (WT) littermates were fasted for 24 h, followed by ∼6 h of refeeding. Plasma FA concentration in WT mice was elevated twofold with fasting, whereas KO mice lacked this elevation, resulting in twofold lower cardiac FA uptake compared with WT mice. Echocardiography showed that fractional shortening was 15% decreased during fasting in WT mice and was associated with steatosis, whereas both of these changes were absent in KO mice. Compared with Langendorff-perfused hearts isolated from fasted WT mice, the isolated KO hearts also displayed higher contractile function and a blunted response to FA. Although cardiac glucose uptake in KO mice was comparable with WT mice under all conditions tested, cardiac VLDL uptake and lipoprotein lipase (LPL) activity were twofold higher in KO mice during fasting. The KO hearts showed undetectable activity of neutral cholesteryl esterase and 40% lower non-LPL triglyceride lipase activity compared with WT hearts in refed conditions accompanied by overt steatosis, normal cardiac function, and increased mRNA expression of adipose differentiation-related protein. Thus, the dissociation between cardiac steatosis and functional sequelae observed in HSL-KO mice suggests that excess FA influx, rather than steatosis per se, appears to play an important role in the pathogenesis of cardiac lipotoxicity.
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Affiliation(s)
- Jinya Suzuki
- Third Dept. of Internal Medicine, Univ. of Fukui, Faculty of Medical Science, Fukui 910-1193, Japan.
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Curcio CA, Johnson M, Huang JD, Rudolf M. Aging, age-related macular degeneration, and the response-to-retention of apolipoprotein B-containing lipoproteins. Prog Retin Eye Res 2009; 28:393-422. [PMID: 19698799 PMCID: PMC4319375 DOI: 10.1016/j.preteyeres.2009.08.001] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The largest risk factor for age-related macular degeneration (ARMD) is advanced age. A prominent age-related change in the human retina is the accumulation of histochemically detectable neutral lipid in normal Bruch's membrane (BrM) throughout adulthood. This change has the potential to have a major impact on physiology of the retinal pigment epithelium (RPE). It occurs in the same compartment as drusen and basal linear deposit, the pathognomonic extracellular, lipid-containing lesions of ARMD. Here we present evidence from light microscopic histochemistry, ultrastructure, lipid profiling of tissues and isolated lipoproteins, and gene expression analysis that this deposition can be accounted for by esterified cholesterol-rich, apolipoprotein B-containing lipoprotein particles constitutively produced by the RPE. This work collectively allows ARMD lesion formation and its aftermath to be conceptualized as a response to the retention of a sub-endothelial apolipoprotein B lipoprotein, similar to a widely accepted model of atherosclerotic coronary artery disease (CAD) (Tabas et al., 2007). This approach provides a wide knowledge base and sophisticated clinical armamentarium that can be readily exploited for the development of new model systems and the future benefit of ARMD patients.
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Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL 35294-0009, USA.
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Råmunddal T, Lindbom M, Scharin-Täng M, Stillemark-Billton P, Boren J, Omerovic E. Overexpression of apolipoprotein-B improves cardiac function and increases survival in mice with myocardial infarction. Biochem Biophys Res Commun 2009; 385:336-40. [PMID: 19460358 DOI: 10.1016/j.bbrc.2009.05.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 05/13/2009] [Indexed: 11/17/2022]
Abstract
BACKGROUND The heart produces apolipoprotein-B containing lipoproteins (apoB) whose function is not well understood. The aim of this study was to evaluate importance of myocardial apoB for cardiac function, structure and survival in myocardial infarction (MI) and heart failure (HF). METHODS AND RESULTS MI was induced in mice (n=137) and myocardial apoB content was measured at 30 min, 3, 6, 24, 48, 120 h and 8 weeks post-MI. Transgenic mice overexpressing apoB (n=27) and genetically matched controls (n=27) were used to study the effects of myocardial apoB on cardiac function, remodeling, arrhythmias and survival after MI. Echocardiography was performed at rest and stress conditions at baseline, 2, 4 and 6 week post-MI and cumulative survival rate was registered. The myocardial apoB content increased both in the injured and the remote myocardium (p<0.05) in response to ischemic injury. ApoB mice had 2-fold higher survival rate (p<0.05) and better systolic function (p<0.05) post-MI. CONCLUSION Overexpression of apoB in the heart increases survival and improves cardiac function after acute MI. Myocardial apoB may be an important cardioprotective system in settings such as myocardial ischemia and HF.
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Affiliation(s)
- Truls Råmunddal
- The Wallenberg Laboratory at Sahlgrenska Academy, Gothenburg University, Bruna Stråket 16, 41345 Gothenburg, Sweden
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