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Wardhani K, Levina A, Grau GER, Lay PA. Fluorescent, phosphorescent, magnetic resonance contrast and radioactive tracer labelling of extracellular vesicles. Chem Soc Rev 2024. [PMID: 38828885 DOI: 10.1039/d2cs00238h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses. Various labeling strategies, such as lipid membrane, surface protein, luminal, nucleic acid, radionuclide, quantum dot labels, and metal complex-based stains, are evaluated for visualizing and characterizing EVs. Direct labelling with fluorescent lipophilic dyes is simple but generally lacks specificity, while surface protein labelling offers selectivity but may affect EV-cell interactions. Luminal and nucleic acid labelling strategies have their own advantages and challenges. Each labelling approach has strengths and weaknesses, which require a suitable probe and technique based on research goals, but new tetranuclear polypyridylruthenium(II) complexes as phosphorescent probes have strong phosphorescence, selective staining, and stability. Future research should prioritize the design of novel fluorescent probes and labelling platforms that can significantly enhance the efficiency, accuracy, and specificity of EV labeling, while preserving their composition and functionality. It is crucial to reduce false positive signals and explore the potential of multimodal imaging techniques to gain comprehensive insights into EVs.
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Affiliation(s)
- Kartika Wardhani
- School of Chemistry, The University of Sydney, Sydney, New South Wales, 2006, Australia.
- Biochemistry and Biotechnology (B-TEK) Group, Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - Aviva Levina
- School of Chemistry, The University of Sydney, Sydney, New South Wales, 2006, Australia.
| | - Georges E R Grau
- Sydney Nano, The University of Sydney, Sydney, New South Wales, 2006, Australia
- Sydney Cancer Network, The University of Sydney, Sydney, New South Wales, 2006, Australia
- Marie Bashir Institute, The University of Sydney, Sydney, New South Wales, 2006, Australia
- Vascular Immunology Unit, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Peter A Lay
- School of Chemistry, The University of Sydney, Sydney, New South Wales, 2006, Australia.
- Sydney Nano, The University of Sydney, Sydney, New South Wales, 2006, Australia
- Sydney Cancer Network, The University of Sydney, Sydney, New South Wales, 2006, Australia
- Marie Bashir Institute, The University of Sydney, Sydney, New South Wales, 2006, Australia
- Sydney Analytical, The University of Sydney, Sydney, New South Wales, 2006, Australia
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2
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Wnętrzak A, Chachaj-Brekiesz A, Kobierski J, Dynarowicz-Latka P. The Structure of Oxysterols Determines Their Behavior at Phase Boundaries: Implications for Model Membranes and Structure-Activity Relationships. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:3-29. [PMID: 38036872 DOI: 10.1007/978-3-031-43883-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
The presence of an additional polar group in the cholesterol backbone increases the hydrophilicity of resulting compounds (oxysterols), determines their arrangement at the phase boundary, and interactions with other lipids and proteins. As a result, physicochemical properties of biomembranes (i.e., elasticity, permeability, and ability to bind proteins) are modified, which in turn may affect their functioning. The observed effect depends on the type of oxysterol and its concentration and can be both positive (e.g., antiviral activity) or negative (disturbance of cholesterol homeostasis, signal transduction, and protein segregation). The membrane activity of oxysterols has been successfully studied using membrane models (vesicles, monolayers, and solid supported films). Membrane models, in contrast to the natural systems, provide the possibility to selectively examine the specific aspect of biomolecule-membrane interactions. Moreover, the gradual increase in the complexity of the used model allows to understand the molecular phenomena occurring at the membrane level. The interest in research on artificial membranes has increased significantly in recent years, mainly due to the development of modern and sophisticated physicochemical methods (static and dynamic) in both the micro- and nanoscale, which are applied with the assistance of powerful theoretical calculations. This review provides an overview of the most important findings on this topic in the current literature.
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Affiliation(s)
- Anita Wnętrzak
- Faculty of Chemistry, Jagiellonian University, Kraków, Poland.
| | | | - Jan Kobierski
- Department of Pharmaceutical Biophysics, Faculty of Pharmacy, Jagiellonian University Medical College, Kraków, Poland
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3
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Ravi S, Duraisamy P, Krishnan M, Martin LC, Manikandan B, Raman T, Sundaram J, Arumugam M, Ramar M. An insight on 7- ketocholesterol mediated inflammation in atherosclerosis and potential therapeutics. Steroids 2021; 172:108854. [PMID: 33930389 DOI: 10.1016/j.steroids.2021.108854] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 11/24/2022]
Abstract
7-ketocholesterol, a toxic oxidative product of oxysterol is a causative agent of several diseases and disabilities concomitant to aging including cardiovascular diseases like atherosclerosis. Auto-oxidation of cholesterol esters present in low-density lipoprotein (LDL) deposits lead to the formation of oxidized LDL (Ox-LDL) along with its byproducts, namely 7KCh. It is predominantly found in atherosclerotic plaque and also found to be more atherogenic than cholesterol by being cytotoxic, interfering with cellular homeostasis. This makes it a serious threat by being the foremost cause of morbidity and mortality worldwide and is likely to become more serious during forth coming years. It involves in mediating inflammatory mechanisms characterized by the advancement of fibroatheroma plaques. The atherosclerotic lesion is composed of Ox-LDL along with fibrotic mass consisting of immune cells and molecules. Macrophages being the specialized phagocytic cells, contribute to removal of detrimental contents of the lesion along with accumulated lipids leading to alteration of its biology and functionality due to its plasticity. Here, we have explored the known as well as proposed mechanisms involved with 7KCh associated atherogenesis along with potential therapeutic strategies for targeting 7KCh as a diagnostic and target in medicine.
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Affiliation(s)
- Sangeetha Ravi
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India
| | | | - Mahalakshmi Krishnan
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Livya C Martin
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Beulaja Manikandan
- Department of Biochemistry, Annai Veilakanni's College for Women, Chennai 600015, India
| | - Thiagarajan Raman
- Department of Advanced Zoology and Biotechnology, Ramakrishna Mission Vivekananda College, Mylapore, Chennai 600004, India
| | - Janarthanan Sundaram
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Munusamy Arumugam
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Manikandan Ramar
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India.
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Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux. Pharmaceut Med 2020; 33:465-498. [PMID: 31933239 PMCID: PMC7101889 DOI: 10.1007/s40290-019-00308-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.
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Dias IH, Borah K, Amin B, Griffiths HR, Sassi K, Lizard G, Iriondo A, Martinez-Lage P. Localisation of oxysterols at the sub-cellular level and in biological fluids. J Steroid Biochem Mol Biol 2019; 193:105426. [PMID: 31301352 DOI: 10.1016/j.jsbmb.2019.105426] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/25/2019] [Accepted: 07/09/2019] [Indexed: 12/16/2022]
Abstract
Oxysterols are oxidized derivatives of cholesterol that are formed enzymatically or via reactive oxygen species or both. Cholesterol or oxysterols ingested as food are absorbed and packed into lipoproteins that are taken up by hepatic cells. Within hepatic cells, excess cholesterol is metabolised to form bile acids. The endoplasmic reticulum acts as the main organelle in the bile acid synthesis pathway. Metabolised sterols originating from this pathway are distributed within other organelles and in the cell membrane. The alterations to membrane oxysterol:sterol ratio affects the integrity of the cell membrane. The presence of oxysterols changes membrane fluidity and receptor orientation. It is well documented that hydroxylase enzymes located in mitochondria facilitate oxysterol production via an acidic pathway. More recently, the presence of oxysterols was also reported in lysosomes. Peroxisomal deficiencies favour intracellular oxysterols accumulation. Despite the low abundance of oxysterols compared to cholesterol, the biological actions of oxysterols are numerous and important. Oxysterol levels are implicated in the pathogenesis of multiple diseases ranging from chronic inflammatory diseases (atherosclerosis, Alzheimer's disease and bowel disease), cancer and numerous neurodegenerative diseases. In this article, we review the distribution of oxysterols in sub-cellular organelles and in biological fluids.
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Affiliation(s)
- Irundika Hk Dias
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK.
| | - Khushboo Borah
- Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford, GU2 7XH, UK
| | - Berivan Amin
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK
| | - Helen R Griffiths
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK; Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford, GU2 7XH, UK
| | - Khouloud Sassi
- Team Bio-PeroxIL, Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism (EA7270)/University Bourgogne Franche-Comté/Inserm, 21000 Dijon, France; Univ. Tunis El Manar, Laboratory of Onco-Hematology (LR05ES05), Faculty of Medicine, Tunis, Tunisia
| | - Gérard Lizard
- Team Bio-PeroxIL, Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism (EA7270)/University Bourgogne Franche-Comté/Inserm, 21000 Dijon, France
| | - Ane Iriondo
- Department of Neurology, Center for Research and Advanced Therapies, CITA-Alzheimer Foundation, San Sebastian, Spain
| | - Pablo Martinez-Lage
- Department of Neurology, Center for Research and Advanced Therapies, CITA-Alzheimer Foundation, San Sebastian, Spain
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Effect of Cholesterol on the Dipole Potential of Lipid Membranes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1115:135-154. [DOI: 10.1007/978-3-030-04278-3_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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Brahmi F, Vejux A, Sghaier R, Zarrouk A, Nury T, Meddeb W, Rezig L, Namsi A, Sassi K, Yammine A, Badreddine I, Vervandier-Fasseur D, Madani K, Boulekbache-Makhlouf L, Nasser B, Lizard G. Prevention of 7-ketocholesterol-induced side effects by natural compounds. Crit Rev Food Sci Nutr 2018; 59:3179-3198. [DOI: 10.1080/10408398.2018.1491828] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Fatiha Brahmi
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- Lab. Biomathématique, Biochimie, Biophysique et Scientométrie, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia, Algeria
| | - Anne Vejux
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
| | - Randa Sghaier
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- Lab-NAFS ‘Nutrition - Functional Food & Vascular Health’, LR12ES05, Université de Monastir, Monastir, Tunisia
- Faculty of Medicine, Lab. Biochemistry, Sousse, Tunisia
| | - Amira Zarrouk
- Lab-NAFS ‘Nutrition - Functional Food & Vascular Health’, LR12ES05, Université de Monastir, Monastir, Tunisia
- Faculty of Medicine, Lab. Biochemistry, Sousse, Tunisia
| | - Thomas Nury
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
| | - Wiem Meddeb
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- LMMA/IPEST, Faculty of Science, University of Carthage, Bizerte, Tunisia
| | - Leila Rezig
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- ESIAT, Lab. Conservation et Valorisation des Aliments, Tunis, Tunisia
| | - Amira Namsi
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- University Tunis El Manar, Faculty of Science of Tunis, Laboratory of Functional Neurophysiology and Pathology, Tunis, Tunisia
| | - Khouloud Sassi
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- Lab. Onco-Hematology, Faculty de Medicine of Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Aline Yammine
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- Bioactive Molecules Research Lab, Faculty of Sciences, Lebanese University, Beirut, Lebanon
| | - Iham Badreddine
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
- Lab. ‘Valorisation des Ressources Naturelles et Environnement’, Université Ibn Zohr, Taroudant, Morocco
| | | | - Khodir Madani
- Lab. Biomathématique, Biochimie, Biophysique et Scientométrie, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia, Algeria
| | - Lila Boulekbache-Makhlouf
- Lab. Biomathématique, Biochimie, Biophysique et Scientométrie, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia, Algeria
| | - Boubker Nasser
- Lab. Neuroscience and Biochemistry, Université Hassan 1er, Settat, Morocco
| | - Gérard Lizard
- Team ‘Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism’, Lab. Bio-PeroxIL, Université de Bourgogne Franche-Comté, Dijon, France
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8
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Lu SM, Fairn GD. 7-Ketocholesterol impairs phagocytosis and efferocytosis via dysregulation of phosphatidylinositol 4,5-bisphosphate. Traffic 2018; 19:591-604. [PMID: 29693767 DOI: 10.1111/tra.12576] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/16/2018] [Accepted: 04/18/2018] [Indexed: 12/27/2022]
Abstract
The plasma membrane is inhomogeneously organized containing both highly ordered and disordered nanodomains. 7-Ketocholesterol (7KC), an oxysterol formed from the nonenzymatic oxidation of cholesterol, is a potent disruptor of membrane order. Importantly, 7KC is a component of oxidized low-density lipoprotein and accumulates in macrophage and foam cells found in arterial plaques. Using a murine macrophage cell line, J774, we report that both IgG-mediated and phosphatidylserine-mediated phagocytic pathways are inhibited by the accumulation of 7KC. Examination of the well-studied Fcγ receptor pathway revealed that the cell surface receptor abundance and ligand binding are unaltered while downstream signaling and activation of spleen tyrosine kinase is not affected. However, while the recruitment of phospholipase Cγ1 was unaffected its apparent enzymatic activity was compromised resulting in sustained phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] levels and polymerized actin at the base of the phagocytic cup. Additionally, we found that 7KC prevented the activation of PLCβ downstream of the P2Y6 G-protein coupled receptor and that 7KC impaired PLCγ activity in response to a direct elevation of cytosolic calcium induced by ionomycin. Finally, we demonstrate that 7KC partly attenuates the activity of rapamycin recruitable constitutively active PLCβ3. Together, our results demonstrate that the accumulation of 7KC impairs macrophage function by altering PtdIns(4,5)P2 catabolism and, thus, impairing actin depolymerization required for the completion of phagocytosis.
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Affiliation(s)
- Stella M Lu
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Toronto, ON, Canada
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Toronto, ON, Canada.,Department of Surgery and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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9
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Khan S, Khan FI, Mohammad T, Khan P, Hasan GM, Lobb KA, Islam A, Ahmad F, Imtaiyaz Hassan M. Exploring molecular insights into the interaction mechanism of cholesterol derivatives with the Mce4A: A combined spectroscopic and molecular dynamic simulation studies. Int J Biol Macromol 2018; 111:548-560. [DOI: 10.1016/j.ijbiomac.2017.12.160] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/16/2017] [Accepted: 12/30/2017] [Indexed: 01/08/2023]
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10
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An H, Brettle M, Lee T, Heng B, Lim CK, Guillemin GJ, Lord MS, Klotzsch E, Geczy CL, Bryant K, Fath T, Tedla N. Soluble LILRA3 promotes neurite outgrowth and synapses formation through high affinity interaction with Nogo 66. J Cell Sci 2016; 129:1198-209. [DOI: 10.1242/jcs.182006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/26/2016] [Indexed: 01/24/2023] Open
Abstract
Inhibitory proteins, particularly Nogo 66, a highly conserved 66 amino acid loop of Nogo A, play key roles in limiting the intrinsic capacity of the central nervous system to regenerate after injury. Ligation of surface Nogo receptors (NgRs) and/or leukocyte immunoglobulin like receptor B2 (LILRB2) and its mouse orthologue the paired-immunoglobulin-like receptor B (PIRB) by Nogo 66 transduces inhibitory signals that potently inhibit neurite outgrowth. Here we show that soluble leukocyte immunoglobulin-like receptor A3 (LILRA3) is a high affinity receptor for Nogo 66, suggesting that LILRA3 might be a competitive antagonist to these cell surface inhibitory receptors. Consistent with this, LILRA3 significantly reversed Nogo 66-mediated inhibition of neurite outgrowth and promoted synapse formation in primary cortical neurons via regulation of the MEK/ERK pathway. LILRA3 represents a new antagonist to Nogo 66-mediated inhibition of neurite outgrowth in the CNS, a function distinct from its immune-regulatory role in leukocytes. This report is also the first to demonstrate that a member of LILR family normally not expressed in rodents exerts functions on mouse neurons through the highly homologous Nogo 66 ligand.
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Affiliation(s)
- Hongyan An
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Merryn Brettle
- Neurodegeneration and Repair Unit, School of Medical Sciences, Department of Anatomy, UNSW, Sydney, Australia
| | - Terry Lee
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Benjamin Heng
- Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Macquarie University, Australia
| | - Chai K. Lim
- Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Macquarie University, Australia
| | - Gilles J. Guillemin
- Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Macquarie University, Australia
| | - Megan S. Lord
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
| | - Enrico Klotzsch
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, ARC Centre of Excellence in Advanced Molecular Imaging, The University of New South Wales, Sydney, NSW, Australia
| | - Carolyn L. Geczy
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Katherine Bryant
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Thomas Fath
- Neurodegeneration and Repair Unit, School of Medical Sciences, Department of Anatomy, UNSW, Sydney, Australia
| | - Nicodemus Tedla
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
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11
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Rao X, Zhong J, Maiseyeu A, Gopalakrishnan B, Villamena FA, Chen LC, Harkema JR, Sun Q, Rajagopalan S. CD36-dependent 7-ketocholesterol accumulation in macrophages mediates progression of atherosclerosis in response to chronic air pollution exposure. Circ Res 2014; 115:770-780. [PMID: 25186795 DOI: 10.1161/circresaha.115.304666] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
RATIONALE Air pollution exposure has been shown to potentiate plaque progression in humans and animals. Our previous studies have suggested a role for oxidized lipids in mediating adverse vascular effect of air pollution. However, the types of oxidized lipids formed in response to air pollutants and how this occurs and their relevance to atherosclerosis are not fully understood. OBJECTIVE To investigate the mechanisms by which particulate matter <2.5 μm (PM2.5) induces progression of atherosclerosis. METHODS AND RESULTS Atherosclerosis-prone ApoE(-/-) or LDLR(-/-) mice were exposed to filtered air or concentrated ambient PM2.5 using a versatile aerosol concentrator enrichment system for 6 months. PM2.5 increased 7-ketocholesterol (7-KCh), an oxidatively modified form of cholesterol, in plasma intermediate density lipoprotein/low-density lipoprotein fraction and in aortic plaque concomitant with progression of atherosclerosis and increased CD36 expression in plaque macrophages from PM2.5-exposed mice. Macrophages isolated from PM2.5-exposed mice displayed increased uptake of oxidized lipids without alterations in their efflux capacity. Consistent with these finding, CD36-positive macrophages displayed a heightened capacity for oxidized lipid uptake. Deficiency of CD36 on hematopoietic cells diminished the effect of air pollution on 7-KCh accumulation, foam cell formation, and atherosclerosis. CONCLUSIONS Our results suggest a potential role for CD36-mediated abnormal accumulations of oxidized lipids, such as 7-KCh, in air pollution-induced atherosclerosis progression.
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Affiliation(s)
- Xiaoquan Rao
- Division of Cardiovascular Medicine, University of Maryland Baltimore, Maryland, USA
| | - Jixin Zhong
- Division of Cardiovascular Medicine, University of Maryland Baltimore, Maryland, USA
| | - Andrei Maiseyeu
- Division of Cardiovascular Medicine, University of Maryland Baltimore, Maryland, USA
| | - Bhavani Gopalakrishnan
- Department of Pharmacology, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Frederick A Villamena
- Department of Pharmacology, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Lung-Chi Chen
- The Department of Environmental Medicine, New York University School of Medicine, Tuxedo, New York, USA
| | - Jack R Harkema
- Center for Integrative Toxicology and Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, USA
| | - Qinghua Sun
- Department of Pharmacology, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, Ohio, USA.,College of Public Health, The Ohio State University, Columbus, Ohio, USA
| | - Sanjay Rajagopalan
- Division of Cardiovascular Medicine, University of Maryland Baltimore, Maryland, USA
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12
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Rosenson RS, Brewer HB, Ansell B, Barter P, Chapman MJ, Heinecke JW, Kontush A, Tall AR, Webb NR. Translation of High-Density Lipoprotein Function Into Clinical Practice. Circulation 2013; 128:1256-67. [DOI: 10.1161/circulationaha.113.000962] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Robert S. Rosenson
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - H. Bryan Brewer
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - Benjamin Ansell
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - Philip Barter
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - M. John Chapman
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - Jay W. Heinecke
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - Anatol Kontush
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - Alan R. Tall
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
| | - Nancy R. Webb
- From the Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY (R.S.R.); Cardiovascular Research Institute, MedStar Research Institute, Washington Hospital Center, Washington, DC (H.B.B.); Atherosclerosis Research Unit, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (B.A.); Centre for Vascular Research at the University of New South Wales, Sydney, Australia (P.B.); Dyslipidemia, Atherosclerosis and Inflammation Research Unit 939, National
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13
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Abstract
Plasma high density lipoproteins (HDL) are small, dense, protein-rich particles compared with other lipoprotein classes; roughly half of total HDL mass is accounted for by lipid components. Phospholipids predominate in the HDL lipidome, accounting for 40-60% of total lipid, with lesser proportions of cholesteryl esters (30-40%), triglycerides (5-12%), and free cholesterol (5-10%). Lipidomic approaches have provided initial insights into the HDL lipidome with identification of over 200 individual molecular lipids species in normolipidemic HDL. Plasma HDL particles, however, reveal high levels of structural, compositional, and functional heterogeneity. Establishing direct relationships between HDL structure, composition, and atheroprotective functions bears the potential to identify clinically relevant HDL subpopulations. Furthermore, development of HDL-based therapies designed to target beneficial subspecies within the circulating HDL pool can be facilitated using this approach. HDL lipidomics can equally contribute to the identification of biomarkers of both normal and deficient HDL functionality, which may prove useful as biomarkers of cardiovascular risk. However, numerous technical issues remain to be addressed in order to make such developments possible. With all technical questions resolved, quantitative analysis of the molecular components of the HDL lipidome will contribute to expand our knowledge of cardiovascular and metabolic diseases.
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Affiliation(s)
- Anatol Kontush
- Dyslipidemia, Inflammation and Atherosclerosis Research Unit (UMR 939), National Institute for Health and Medical Research (INSERM), Paris, France; Université Pierre et Marie Curie 6, Paris, France; Groupe Hospitalier Pitié Salpétrière, AP-HP, Paris, France; Institute of Cardiometabolism and Nutrition (ICAN), Paris, France
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14
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Abstract
PURPOSE OF REVIEW To offer a comprehensive review on the roles that oxysterols synthesized or engulfed by macrophages, or oxysterol-binding proteins in these cells, play in the development and progression of atherosclerotic lesions. RECENT FINDINGS Oxysterols abundant within the plaque have the capacity to potentiate macrophage proinflammatory signaling and to induce cell death. These activities may contribute to formation of the complex lesion, expansion of the necrotic core, and to plaque rupture. On the contrary, several endogenous oxysterols generated by cholesterol hydroxylases act as ligands of liver X receptors, stimulate macrophage cholesterol efflux, repress proinflammatory signaling, and promote macrophage survival, counteracting lesion progression. Cytoplasmic oxysterol-binding proteins represent a family of sterol and phosphoinositide sensors that may contribute to the regulatory impact of these bioactive lipids on processes relevant in the context of atherogenesis. SUMMARY The generation and deposition of oxysterols within the developing plaque is envisioned to modulate macrophage lipid metabolism, to affect the delicate balance of proinflammatory and anti-inflammatory processes, and to impact cell fate decisions, thus, determining whether the lesion remains benign or whether it develops into a hazardous, vulnerable plaque.
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Affiliation(s)
- Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research bInstitute of Biomedicine, Anatomy, University of Helsinki, Helsinki, Finland.
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15
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Lemaire-Ewing S, Lagrost L, Néel D. Lipid rafts: a signalling platform linking lipoprotein metabolism to atherogenesis. Atherosclerosis 2011; 221:303-10. [PMID: 22071358 DOI: 10.1016/j.atherosclerosis.2011.10.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 09/22/2011] [Accepted: 10/12/2011] [Indexed: 01/16/2023]
Abstract
Lipid rafts are microdomains of the plasma membrane which are enriched in cholesterol and sphingolipids. They serve as a platform for signal transduction, in particular during immune and inflammatory responses. As hypercholesterolemia and inflammation are two key elements of atherogenesis, it is conceivable that the cholesterol and cholesterol oxide content of lipid rafts might influence the inflammatory signalling pathways, thus modulating the development of atherosclerosis. In support of this emerging view, lipid rafts have been shown to be involved in several key steps of atherogenesis, such as the oxysterol-mediated apoptosis of vascular cells, the blunted ability of high density lipoproteins (HDL) to exert anti-inflammatory effects, and the exacerbated secretion of pro-inflammatory cytokines by immune cells. Additional studies are now required to address the relative contribution of lipid raft abnormalities to the pathophysiology of atherosclerosis and cardiovascular disease.
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16
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The effect of oxycholesterols on thermo-induced membrane dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2245-51. [DOI: 10.1016/j.bbamem.2011.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/12/2011] [Accepted: 05/02/2011] [Indexed: 11/22/2022]
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17
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Le Lay S, Rodriguez M, Jessup W, Rentero C, Li Q, Cartland S, Grewal T, Gaus K. Caveolin-1-mediated apolipoprotein A-I membrane binding sites are not required for cholesterol efflux. PLoS One 2011; 6:e23353. [PMID: 21858084 PMCID: PMC3155548 DOI: 10.1371/journal.pone.0023353] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/13/2011] [Indexed: 11/18/2022] Open
Abstract
Caveolin-1 (Cav1), a structural protein required for the formation of invaginated membrane domains known as caveolae, has been implicated in cholesterol trafficking and homeostasis. Here we investigated the contribution of Cav1 to apolipoprotein A-I (apoA-I) cell surface binding and intracellular processing using mouse embryonic fibroblasts (MEFs) derived from wild type (WT) or Cav1-deficient (Cav1(-/-)) animals. We found that cells expressing Cav1 have 2.6-fold more apoA-I binding sites than Cav1(-/-) cells although these additional binding sites are not associated with detergent-free lipid rafts. Further, Cav1-mediated binding targets apoA-I for internalization and degradation and these processes are not correlated to cholesterol efflux. Despite lower apoA-I binding, cholesterol efflux from Cav1(-/-) MEFs is 1.7-fold higher than from WT MEFs. Stimulation of ABCA1 expression with an LXR agonist enhances cholesterol efflux from both WT and Cav1(-/-) cells without increasing apoA-I surface binding or affecting apoA-I processing. Our results indicate that there are at least two independent lipid binding sites for apoA-I; Cav1-mediated apoA-I surface binding and uptake is not linked to cholesterol efflux, indicating that membrane domains other than caveolae regulate ABCA1-mediated cholesterol efflux.
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Affiliation(s)
- Soazig Le Lay
- Centre de Recherche des Cordeliers, INSERM, U872, Paris, France
| | - Macarena Rodriguez
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Wendy Jessup
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Carles Rentero
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Qiong Li
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Siân Cartland
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, Australia
| | - Katharina Gaus
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
- * E-mail:
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18
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Interaction of two oxysterols, 7-ketocholesterol and 25-hydroxycholesterol, with phosphatidylcholine and sphingomyelin in model membranes. Chem Phys Lipids 2010; 163:586-93. [DOI: 10.1016/j.chemphyslip.2010.05.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 04/07/2010] [Accepted: 05/04/2010] [Indexed: 02/03/2023]
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19
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Kontush A, Chapman MJ. Functionally defective high-density lipoprotein: a new therapeutic target at the crossroads of dyslipidemia, inflammation, and atherosclerosis. Pharmacol Rev 2006; 58:342-74. [PMID: 16968945 DOI: 10.1124/pr.58.3.1] [Citation(s) in RCA: 533] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
High-density lipoproteins (HDL) possess key atheroprotective biological properties, including cellular cholesterol efflux capacity, and anti-oxidative and anti-inflammatory activities. Plasma HDL particles are highly heterogeneous in physicochemical properties, metabolism, and biological activity. Within the circulating HDL particle population, small, dense HDL particles display elevated cellular cholesterol efflux capacity, afford potent protection of atherogenic low-density lipoprotein against oxidative stress and attenuate inflammation. The antiatherogenic properties of HDL can, however be compromised in metabolic diseases associated with accelerated atherosclerosis. Indeed, metabolic syndrome and type 2 diabetes are characterized not only by elevated cardiovascular risk and by low HDL-cholesterol (HDL-C) levels but also by defective HDL function. Functional HDL deficiency is intimately associated with alterations in intravascular HDL metabolism and structure. Indeed, formation of HDL particles with attenuated antiatherogenic activity is mechanistically related to core lipid enrichment in triglycerides and cholesteryl ester depletion, altered apolipoprotein A-I (apoA-I) conformation, replacement of apoA-I by serum amyloid A, and covalent modification of HDL protein components by oxidation and glycation. Deficient HDL function and subnormal HDL-C levels may act synergistically to accelerate atherosclerosis in metabolic disease. Therapeutic normalization of attenuated antiatherogenic HDL function in terms of both particle number and quality of HDL particles is the target of innovative pharmacological approaches to HDL raising, including inhibition of cholesteryl ester transfer protein, enhanced lipidation of apoA-I with nicotinic acid and infusion of reconstituted HDL or apoA-I mimetics. A preferential increase in circulating concentrations of HDL particles possessing normalized antiatherogenic activity is therefore a promising therapeutic strategy for the treatment of common metabolic diseases featuring dyslipidemia, inflammation, and premature atherosclerosis.
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Affiliation(s)
- Anatol Kontush
- Dyslipoproteinemia and Atherosclerosis Research Unit, National Institute for Health and Medical Research, Hôpital de la Pitié, 83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
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20
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Jessup W, Gelissen IC, Gaus K, Kritharides L. Roles of ATP binding cassette transporters A1 and G1, scavenger receptor BI and membrane lipid domains in cholesterol export from macrophages. Curr Opin Lipidol 2006; 17:247-57. [PMID: 16680029 DOI: 10.1097/01.mol.0000226116.35555.eb] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW The initial steps of reverse cholesterol transport involve export of cholesterol from peripheral cells to plasma lipoproteins for subsequent delivery to the liver. The review discusses recent developments in our understanding of how these steps occur, with particular emphasis on the macrophage, the major site of cellular cholesterol accumulation in atherosclerosis. RECENT FINDINGS ATP binding cassette transporter (ABC) A1 exports cholesterol and phospholipid to lipid-free apolipoproteins, while ATP binding cassette transporter G1 and scavenger receptor BI export cholesterol to phospholipid-containing acceptors. ABCA1-dependent cholesterol export involves an initial interaction of apolipoprotein AI with lipid raft membrane domains, although ABCA1 and most exported cholesterol are not raft associated. ABCG1 exports cholesterol to HDL and other phospholipid-containing acceptors. These include particles generated during lipidation of apoAI by ABCA1, suggesting that the two transporters cooperate in cholesterol export. Scavenger receptor BI is atheroprotective, mediating clearance of HDL cholesterol by the liver. The relative contributions of scavenger receptor BI and ABCG to cholesterol export to HDL from macrophages is unclear and may depend on cellular cholesterol status and the cholesterol gradient between cell and acceptor. SUMMARY The presence of distinct pathways for cholesterol efflux to lipid-free apolipoprotein AI and phospholipid-containing HDL species clarifies our understanding of reverse cholesterol transport, and provides new opportunities for its therapeutic manipulation.
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Affiliation(s)
- Wendy Jessup
- Centre for Vascular Research, at the School of Medical Sciences, University of New South Wales, Sydney, Australia.
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21
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Favari E, Zimetti F, Bortnick AE, Adorni MP, Zanotti I, Canavesi M, Bernini F. Impaired ATP-binding cassette transporter A1-mediated sterol efflux from oxidized LDL-loaded macrophages. FEBS Lett 2005; 579:6537-42. [PMID: 16289478 DOI: 10.1016/j.febslet.2005.10.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Accepted: 10/21/2005] [Indexed: 10/25/2022]
Abstract
We investigated the interaction of oxidized low density lipoprotein (OxLDL) with the ATP-binding cassette A1 (ABCA1) pathway in J774 macrophages. Cellular efflux to apolipoprotein AI (apo-AI) of OxLDL-derived cholesterol was lower than efflux of cholesterol derived from acetylated low density lipoprotein (AcLDL). ABCA1 upregulation by 8-(4-chlorophenylthio)adenosine 3':5'-cyclic monophosphate (cpt-cAMP) or 22 (R)-hydroxycholesterol (22-OH) and 9-cis retinoic acid (9cRA) increased the efflux to apo-AI of cellular sterols derived from AcLDL, but not of those from OxLDL. AcLDL, but not OxLDL, induced ABCA1 protein content and activity in J774. However, OxLDL did not influence J774 ABCA1 upregulation by cpt-cAMP or 22-OH/9cRA. We conclude that sterols released to cells by OxLDL are available neither as substrate nor as modulator of ABCA1.
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Affiliation(s)
- Elda Favari
- Department of Pharmacological and Biological Sciences, and Applied Chemistries, University of Parma, Area delle Scienze 27/A, 43100 Parma, Italy
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22
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Gaus K, Rodriguez M, Ruberu KR, Gelissen I, Sloane TM, Kritharides L, Jessup W. Domain-specific lipid distribution in macrophage plasma membranes. J Lipid Res 2005; 46:1526-38. [PMID: 15863834 DOI: 10.1194/jlr.m500103-jlr200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid rafts, defined as cholesterol- and sphingolipid-rich domains, provide specialized lipid environments understood to regulate the organization and function of many plasma membrane proteins. Growing evidence of their existence, protein cargo, and regulation is based largely on the study of isolated lipid rafts; however, the consistency and validity of common isolation methods is controversial. Here, we provide a detailed and direct comparison of the lipid and protein composition of plasma membrane "rafts" prepared from human macrophages by different methods, including several detergent-based isolations and a detergent-free method. We find that detergent-based and detergent-free methods can generate raft fractions with similar lipid contents and a biophysical structure close to that previously found on living cells, even in cells not expressing caveolin-1, such as primary human macrophages. However, important differences between isolation methods are demonstrated. Triton X-100-resistant rafts are less sensitive to cholesterol or sphingomyelin depletion than those prepared by detergent-free methods. Moreover, we show that detergent-based methods can scramble membrane lipids during the isolation process, reorganizing lipids previously in sonication-derived nonraft domains to generate new detergent-resistant rafts. The role of rafts in regulating the biological activities of macrophage plasma membrane proteins may require careful reevaluation using multiple isolation procedures, analyses of lipids, and microscopic techniques.
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Affiliation(s)
- Katharina Gaus
- Centre for Vascular Research at the School of Medical Sciences, University of New South Wales, and Department of Haematology, Prince of Wales Hospital, Sydney, NSW Australia.
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23
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Campbell S, Gaus K, Bittman R, Jessup W, Crowe S, Mak J. The raft-promoting property of virion-associated cholesterol, but not the presence of virion-associated Brij 98 rafts, is a determinant of human immunodeficiency virus type 1 infectivity. J Virol 2004; 78:10556-65. [PMID: 15367622 PMCID: PMC516414 DOI: 10.1128/jvi.78.19.10556-10565.2004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid rafts are enriched in cholesterol and sphingomyelin and are isolated on the basis of insolubility in detergents, such as Brij 98 and Triton X-100. Recent work by Holm et al. has shown that rafts insoluble in Brig 98 can be found in human immunodeficiency virus type 1 (HIV-1) virus-like particles, although it is not known whether raft-like structures are present in authentic HIV-1 and it is unclear whether a virion-associated raft-like structure is required for HIV replication. Independently, it was previously reported that virion-associated cholesterol is critical for HIV-1 infectivity, although the specific requirement of virion cholesterol in HIV-1 was not examined. In the present study, we have demonstrated that infectious wild-type HIV-1 contains Brij 98 rafts but only minimal amounts of Triton X-100 rafts. To directly assess the functional requirement of virion-associated rafts and various features of cholesterol on HIV-1 replication, we replaced virion cholesterol with exogenous cholesterol analogues that have demonstrated either raft-promoting or -inhibiting capacity in model membranes. We observed that variable concentrations of exogenous analogues are required to replace a defined amount of virion-associated cholesterol, showing that structurally diverse cholesterol analogues have various affinities toward HIV-1. We found that replacement of 50% of virion cholesterol with these exogenous cholesterol analogues did not eliminate the presence of Brij 98 rafts in HIV-1. However, the infectivity levels of the lipid-modified HIV-1s directly correlate with the raft-promoting capacities of these cholesterol analogues. Our data provide the first direct assessment of virion-associated Brij 98 rafts in retroviral replication and illustrate the importance of the raft-promoting property of virion-associated cholesterol in HIV-1 replication.
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Affiliation(s)
- Shahan Campbell
- Macfarlane Burnet Institute for Medical Research and Public Health, Cnr Punt and Commercial Roads, Melbourne 3004, Victoria, Australia
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24
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Risé P, Camera M, Caruso D, Ghezzi S, Visioli F, Galli C. Synthesis of long-chain polyunsaturated fatty acids is inhibited in vivo in hypercholesterolemic rabbits and in vitro by oxysterols. Prostaglandins Leukot Essent Fatty Acids 2004; 71:79-86. [PMID: 15207522 DOI: 10.1016/j.plefa.2003.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2003] [Accepted: 12/12/2003] [Indexed: 10/26/2022]
Abstract
Plasma total lipids, total cholesterol (cholesterol esters and free cholesterol) and oxysterol (mainly 7 beta-hydroxycholesterol (7 beta OH)) concentrations were significantly elevated in New Zealand rabbits fed a 2% cholesterol-containing diet with respect to controls fed the same diet without cholesterol. In addition, linoleic (18:2 n-6) and alpha-linolenic acid (18:3 n-3) plasma concentrations were significantly elevated in hypercholesterolemic rabbits, while concentrations of long-chain n-6 and n-3 derivatives were reduced. Studies in monocytic cell line THP-1 revealed that 7 beta OH markedly inhibited the conversion of 18:2 to 20:4 n-6 and of 18:3 to 22:6 n-3, indicating depression of the desaturation steps; in particular the inhibition was greater for the Delta 5 desaturation step. Furthermore, experiments of Real-Time PCR showed that 5-10 microM 7 beta OH decreased the Delta 5 gene expression. In conclusion, atherogenic oxysterols interfere with the production of long-chain polyunsaturated fatty acids from their precursors both in hypercholesterolemic rabbits and in cultured cells.
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Affiliation(s)
- P Risé
- Department of Pharmacological Sciences, University of Milan, via Balzaretti 9, 20133 Milan, Italy.
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25
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Fu Y, Hoang A, Escher G, Parton RG, Krozowski Z, Sviridov D. Expression of Caveolin-1 Enhances Cholesterol Efflux in Hepatic Cells. J Biol Chem 2004; 279:14140-6. [PMID: 14729661 DOI: 10.1074/jbc.m311061200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HepG2 cells were stably transfected with human caveolin-1 (HepG2/cav cells). Transfection resulted in expression of caveolin-1 mRNA, a high abundance of caveolin-1 protein, and the formation of caveolae on the plasma membrane. Cholesterol efflux from HepG2/cav cells was 280 and 45% higher than that from parent HepG2 cells when human plasma and human apoA-I, respectively, were used as acceptors. The difference in efflux was eliminated by treatment of cells with progesterone. There was no difference in cholesterol efflux to cyclodextrin. Cholesterol efflux from plasma membrane vesicles was similar for the two cell types. Transfection led to a 40% increase in the amount of plasma membrane cholesterol in cholesterol-rich domains (caveolae and/or rafts) and a 67% increase in the rate of cholesterol trafficking from intracellular compartments to these domains. Cholesterol biosynthesis in HepG2/cav cells was increased by 2-fold, and cholesterol esterification was reduced by 50% compared with parent HepG2 cells. The proliferation rate of transfected cells was significantly lower than that of non-transfected cells. Transfection did not affect expression of ABCA1 or the abundance of ABCA1 protein, but decreased secretion of apoA-I. We conclude that overexpression of caveolin-1 in hepatic cells stimulates cholesterol efflux by enhancing transfer of cholesterol to cholesterol-rich domains in the plasma membrane.
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Affiliation(s)
- Ying Fu
- Wynn Domain, Baker Heart Research Institute, Melbourne, Victoria 8008, Australia
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26
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Gaus K, Kritharides L, Schmitz G, Boettcher A, Drobnik W, Langmann T, Quinn CM, Death A, Dean RT, Jessup W. Apolipoprotein A-1 interaction with plasma membrane lipid rafts controls cholesterol export from macrophages. FASEB J 2004; 18:574-6. [PMID: 14734645 DOI: 10.1096/fj.03-0486fje] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cholesterol efflux to apolipoprotein A-1 (apoA-1) from cholesterol-loaded macrophages is an important anti-atherosclerotic mechanism in reverse cholesterol transport. We recently provided kinetic evidence for two distinct pathways for cholesterol efflux to apoA-1 [Gaus et al. (2001) Biochemistry 40, 9363]. Cholesterol efflux from two membrane pools occurs sequentially with different kinetics; a small pool rapidly effluxed over the first hour, followed by progressive release from a major, slow efflux pool over several hours. In the present study, we propose that the rapid and slow cholesterol efflux pools represent cholesterol derived from lipid raft and nonraft domains of the plasma membrane, respectively. We provide direct evidence that apoA-1 binds to both lipid raft and nonraft domains of the macrophage plasma membrane. Conditions that selectively deplete plasma membrane lipid raft cholesterol, such as incorporation of 7-ketocholesterol or rapid exposure to cyclodextrins, block apoA-1 binding to these domains but also inhibit cholesterol efflux from the major, slow pool. We propose that cholesterol exported to apoA-1 from this major slow efflux pool derives from nonraft regions of the plasma membrane but that the interaction of apoA-1 with lipid rafts is necessary to stimulate this efflux.
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Affiliation(s)
- Katharina Gaus
- Macrophage Biology Group, Centre for Vascular Research, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
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27
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Gaus K, Gratton E, Kable EPW, Jones AS, Gelissen I, Kritharides L, Jessup W. Visualizing lipid structure and raft domains in living cells with two-photon microscopy. Proc Natl Acad Sci U S A 2003; 100:15554-9. [PMID: 14673117 PMCID: PMC307606 DOI: 10.1073/pnas.2534386100] [Citation(s) in RCA: 391] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The lateral organization of cellular membranes is formed by the clustering of specific lipids, such as cholesterol and sphingolipids, into highly condensed domains (termed lipid rafts). Hence such domains are distinct from the remaining membrane by their lipid structure (liquid-ordered vs. -disordered domains). Here, we directly visualize membrane lipid structure of living cells by using two-photon microscopy. In macrophages, liquid-ordered domains are particularly enriched on membrane protrusions (filopodia), adhesion points and cell-cell contacts and cover 10-15% of the cell surface at 37 degrees C. By deconvoluting the images, we demonstrate the existence of phase separation in vivo. We compare the properties of microscopically visible domains (<1 microm2), with those of isolated detergent-resistant membranes and provide evidence that membrane coverage by lipid rafts and their fluidity are principally governed by cholesterol content, thereby providing strong support for the lipid raft hypothesis.
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Affiliation(s)
- Katharina Gaus
- Centre for Vascular Research at the University of New South Wales and Department of Haematology, Prince of Wales Hospital, Sydney NSW 2052, Australia.
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28
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Liu SM, Cogny A, Kockx M, Dean RT, Gaus K, Jessup W, Kritharides L. Cyclodextrins differentially mobilize free and esterified cholesterol from primary human foam cell macrophages. J Lipid Res 2003; 44:1156-66. [PMID: 12671029 DOI: 10.1194/jlr.m200464-jlr200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human monocyte-derived foam cell macrophages (HMFCs) are resistant to cholesterol efflux mediated by physiological acceptors. The role of the plasma membrane in regulating depletion of free cholesterol (FC) and of cholesteryl ester (CE) was investigated using cyclodextrins (CDs). HMFCs were incubated in media containing CDs (1.0 mg/ml, approximately 0.7 mM) with low [hydroxypropyl-beta-CD (HP-CD)] or high [trimethyl-beta-CD (TM-CD)] affinity for cholesterol in the presence or absence of phospholipid vesicles (PLVs). Low-affinity HP-CD caused minimal cholesterol efflux on its own, but HP-CD+ PLV depleted cell FC and CE to 54.5 +/- 6.7% of control by 24 h. TM-CD depleted FC at least as well as HP-CD+PLV but without depleting CE, even when combined with PLV. This was not explained by acceptor saturation, instability of PLV vesicles, de novo cholesterol synthesis, kinetically distinct cholesterol pools, or inhibition of CE hydrolysis. TM-CD did, however, deplete CE when lower concentrations of TM-CD were combined with PLV and when acetyl-CoA cholesteryl acyltransferase was inhibited. TM-CD caused much greater depletion of plasma membrane cholesterol than HP-CD without depleting plasma membrane sphingomyelin. It is concluded that differential depletion of plasma membrane cholesterol pools regulates cholesterol efflux and CE clearance in human macrophages.
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Affiliation(s)
- Sue M Liu
- Heart Research Institute, Camperdown, Sydney New South Wales, Australia
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29
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Escher G, Krozowski Z, Croft KD, Sviridov D. Expression of sterol 27-hydroxylase (CYP27A1) enhances cholesterol efflux. J Biol Chem 2003; 278:11015-9. [PMID: 12531903 DOI: 10.1074/jbc.m212780200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cholesterol efflux from CHOP cells transfected with sterol 27-hydroxylase (CYP27A1) was compared with non-transfected and mock-transfected cells. Transfection caused expression of CYP27A1, formation of 27-hydroxycholesterol, and inhibition of cholesterol biosynthesis. Transfection enhanced cholesterol efflux to apolipoprotein A-I or human plasma by 2-3-fold but did not affect the efflux in the absence of acceptor. The analysis of released sterols revealed that 27-hydroxycholesterol represented only a small proportion of sterols, most of which was non-oxidized cholesterol. Time course and dose dependence studies showed that expression of CYP27A1 in CHOP cells mostly affected the efflux of the "fast" cholesterol pool, and relatively more cholesterol was released with low concentrations of an acceptor. Preincubation of non-transfected cells with exogenous 27-hydroxycholesterol (10(-9) and 10(-7) m) led to the stimulation of cholesterol efflux by 24-60%. Expression of CYP27A1 in CHOP cells did not affect ABCA1 expression and abundance of ABCA1 protein. Thus, introduction of CYP27A1 into cells stimulates cholesterol efflux and therefore may increase protection against atherosclerosis.
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Affiliation(s)
- Genevieve Escher
- Wynn Domain, Baker Medical Research Institute, Melbourne, Victoria 8008, Australia
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30
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Abstract
Macrophages are important participants in the development of atherosclerotic lesions, in cholesterol accumulation, as mediators of the immune response, and as sources of secreted enzymes and growth factors. Besides potentially contributing to local oxidation of lesion lipoproteins, many aspects of macrophage function can be affected by interaction with oxidized lipoproteins. Here we review macrophage responses to oxidized lipoproteins and provide novel data on the effects of a major oxidation product, 7-ketocholesterol, on high-density lipoprotein (HDL) function in cholesterol removal from macrophages.
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Affiliation(s)
- Wendy Jessup
- Cell Biology Group, Heart Research Institute, 145 Missenden Road, Camperdown, Sydney, NSW 2050, Australia.
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31
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de Grey ADNJ. The reductive hotspot hypothesis of mammalian aging: membrane metabolism magnifies mutant mitochondrial mischief. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:2003-9. [PMID: 11985576 DOI: 10.1046/j.1432-1033.2002.02868.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A severe challenge to the idea that mitochondrial DNA mutations play a major role in the aging process in mammals is that clear loss-of-function mutations accumulate only to very low levels (under 1% of total) in almost any tissue, even by very old age. Their accumulation is punctate: some cells become nearly devoid of wild-type mitochondrial DNA and exhibit no activity for the partly mitochondrially encoded enzyme cytochrome c oxidase. Such cells accumulate in number with aging, suggesting that they survive indefinitely, which is itself paradoxical. The reductive hotspot hypothesis suggests that these cells adjust their metabolism to use plasma membrane electron transport as a substitute for the mitochondrial electron transport chain in the reoxidation of reduced dinucleotides, and that, like mitochondrial electron transport, this process is imperfect and generates superoxide as a side-effect. This superoxide, generated on the outside of the cell, can potentially initiate classical free radical chemistry including lipid peroxidation chain reactions in circulating material such as lipoproteins. These, in turn, can be toxic to mitochondrially nonmutant cells that import them to satisfy their cholesterol requirements. Thus, the relatively few cells that have lost oxidative phosphorylation capacity may be toxic to the rest of the body. In this minireview, recent results relevant to this hypothesis are surveyed and approaches to intervening in the proposed process are discussed.
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