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Sharma A, Choi JSY, Stefanovic N, Al-Sharea A, Simpson DS, Mukhamedova N, Jandeleit-Dahm K, Murphy AJ, Sviridov D, Vince JE, Ritchie RH, de Haan JB. Specific NLRP3 Inhibition Protects Against Diabetes-Associated Atherosclerosis. Diabetes 2021; 70:772-787. [PMID: 33323396 DOI: 10.2337/db20-0357] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 12/01/2020] [Indexed: 11/13/2022]
Abstract
Low-grade persistent inflammation is a feature of diabetes-driven vascular complications, in particular activation of the Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome to trigger the maturation and release of the inflammatory cytokine interleukin-1β (IL-1β). We investigated whether inhibiting the NLRP3 inflammasome, through the use of the specific small-molecule NLRP3 inhibitor MCC950, could reduce inflammation, improve vascular function, and protect against diabetes-associated atherosclerosis in the streptozotocin-induced diabetic apolipoprotein E-knockout mouse. Diabetes led to an approximately fourfold increase in atherosclerotic lesions throughout the aorta, which were significantly attenuated with MCC950 (P < 0.001). This reduction in lesions was associated with decreased monocyte-macrophage content, reduced necrotic core, attenuated inflammatory gene expression (IL-1β, tumor necrosis factor-α, intracellular adhesion molecule 1, and MCP-1; P < 0.05), and reduced oxidative stress, while maintaining fibrous cap thickness. Additionally, vascular function was improved in diabetic vessels of mice treated with MCC950 (P < 0.05). In a range of cell lines (murine bone marrow-derived macrophages, human monocytic THP-1 cells, phorbol 12-myristate 13-acetate-differentiated human macrophages, and aortic smooth muscle cells from humans with diabetes), MCC950 significantly reduced IL-1β and/or caspase-1 secretion and attenuated leukocyte-smooth muscle cell interactions under high glucose or lipopolysaccharide conditions. In summary, MCC950 reduces plaque development, promotes plaque stability, and improves vascular function, suggesting that targeting NLRP3-mediated inflammation is a novel therapeutic strategy to improve diabetes-associated vascular disease.
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Affiliation(s)
- Arpeeta Sharma
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Judy S Y Choi
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Nada Stefanovic
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Annas Al-Sharea
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Daniel S Simpson
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | | | - Karin Jandeleit-Dahm
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, Victoria, Australia
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andrew J Murphy
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - James E Vince
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Rebecca H Ritchie
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Judy B de Haan
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Victoria, Australia
- Faculty of Science, Engineering and Technology, Swinburne University, Melbourne, Victoria, Australia
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2
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Ohkawa R, Low H, Mukhamedova N, Fu Y, Lai SJ, Sasaoka M, Hara A, Yamazaki A, Kameda T, Horiuchi Y, Meikle PJ, Pernes G, Lancaster G, Ditiatkovski M, Nestel P, Vaisman B, Sviridov D, Murphy A, Remaley AT, Sviridov D, Tozuka M. Cholesterol transport between red blood cells and lipoproteins contributes to cholesterol metabolism in blood. J Lipid Res 2020; 61:1577-1588. [PMID: 32907987 DOI: 10.1194/jlr.ra120000635] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lipoproteins play a key role in transport of cholesterol to and from tissues. Recent studies have also demonstrated that red blood cells (RBCs), which carry large quantities of free cholesterol in their membrane, play an important role in reverse cholesterol transport. However, the exact role of RBCs in systemic cholesterol metabolism is poorly understood. RBCs were incubated with autologous plasma or isolated lipoproteins resulting in a significant net amount of cholesterol moved from RBCs to HDL, while cholesterol from LDL moved in the opposite direction. Furthermore, the bi-directional cholesterol transport between RBCs and plasma lipoproteins was saturable and temperature-, energy-, and time-dependent, consistent with an active process. We did not find LDLR, ABCG1, or scavenger receptor class B type 1 in RBCs but found a substantial amount of ABCA1 mRNA and protein. However, specific cholesterol efflux from RBCs to isolated apoA-I was negligible, and ABCA1 silencing with siRNA or inhibition with vanadate and Probucol did not inhibit the efflux to apoA-I, HDL, or plasma. Cholesterol efflux from and cholesterol uptake by RBCs from Abca1 +/+ and Abca1 -/- mice were similar, arguing against the role of ABCA1 in cholesterol flux between RBCs and lipoproteins. Bioinformatics analysis identified ABCA7, ABCG5, lipoprotein lipase, and mitochondrial translocator protein as possible candidates that may mediate the cholesterol flux. Together, these results suggest that RBCs actively participate in cholesterol transport in the blood, but the role of cholesterol transporters in RBCs remains uncertain.
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Affiliation(s)
- Ryunosuke Ohkawa
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Baker Heart and Diabetes Institute, Melbourne, Australia.
| | - Hann Low
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | - Ying Fu
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Shao-Jui Lai
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mai Sasaoka
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ayuko Hara
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Azusa Yamazaki
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takahiro Kameda
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuna Horiuchi
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Peter J Meikle
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Gerard Pernes
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | | | - Paul Nestel
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Boris Vaisman
- Lipoprotein Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Denis Sviridov
- Lipoprotein Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Andrew Murphy
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Alan T Remaley
- Lipoprotein Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
| | - Minoru Tozuka
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Life Science Research Center, Nagano Children's Hospital, Azumino, Japan
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3
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Low H, Mukhamedova N, Capettini LDSA, Xia Y, Carmichael I, Cody SH, Huynh K, Ditiatkovski M, Ohkawa R, Bukrinsky M, Meikle PJ, Choi SH, Field S, Miller YI, Sviridov D. Cholesterol Efflux-Independent Modification of Lipid Rafts by AIBP (Apolipoprotein A-I Binding Protein). Arterioscler Thromb Vasc Biol 2020; 40:2346-2359. [PMID: 32787522 PMCID: PMC7530101 DOI: 10.1161/atvbaha.120.315037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE AIBP (apolipoprotein A-I binding protein) is an effective and selective regulator of lipid rafts modulating many metabolic pathways originating from the rafts, including inflammation. The mechanism of action was suggested to involve stimulation by AIBP of cholesterol efflux, depleting rafts of cholesterol, which is essential for lipid raft integrity. Here we describe a different mechanism contributing to the regulation of lipid rafts by AIBP. Approach and Results: We demonstrate that modulation of rafts by AIBP may not exclusively depend on the rate of cholesterol efflux or presence of the key regulator of the efflux, ABCA1 (ATP-binding cassette transporter A-I). AIBP interacted with phosphatidylinositol 3-phosphate, which was associated with increased abundance and activation of Cdc42 and rearrangement of the actin cytoskeleton. Cytoskeleton rearrangement was accompanied with reduction of the abundance of lipid rafts, without significant changes in the lipid composition of the rafts. The interaction of AIBP with phosphatidylinositol 3-phosphate was blocked by AIBP substrate, NADPH (nicotinamide adenine dinucleotide phosphate), and both NADPH and silencing of Cdc42 interfered with the ability of AIBP to regulate lipid rafts and cholesterol efflux. CONCLUSIONS Our findings indicate that an underlying mechanism of regulation of lipid rafts by AIBP involves PIP-dependent rearrangement of the cytoskeleton.
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Affiliation(s)
- Hann Low
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Nigora Mukhamedova
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Luciano Dos Santos Aggum Capettini
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.).,Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil (L.d.S.A.C.)
| | - Yining Xia
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Irena Carmichael
- Department of Monash Micro Imaging, Monash University, Melbourne, VIC, Australia (I.C., S.H.C.)
| | - Stephen H Cody
- Department of Monash Micro Imaging, Monash University, Melbourne, VIC, Australia (I.C., S.H.C.)
| | - Kevin Huynh
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Michael Ditiatkovski
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Ryunosuke Ohkawa
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.).,Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan (R.O.)
| | - Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, DC (M.B.)
| | - Peter J Meikle
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Soo-Ho Choi
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Seth Field
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Yury I Miller
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.).,Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia (D.S.)
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4
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Ditiatkovski M, Mukhamedova N, Dragoljevic D, Hoang A, Low H, Pushkarsky T, Fu Y, Carmichael I, Hill AF, Murphy AJ, Bukrinsky M, Sviridov D. Modification of lipid rafts by extracellular vesicles carrying HIV-1 protein Nef induces redistribution of amyloid precursor protein and Tau, causing neuronal dysfunction. J Biol Chem 2020; 295:13377-13392. [PMID: 32732283 DOI: 10.1074/jbc.ra120.014642] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/16/2020] [Indexed: 12/13/2022] Open
Abstract
HIV-associated neurocognitive disorders (HANDs) are a frequent outcome of HIV infection. Effective treatment of HIV infection has reduced the rate of progression and severity but not the overall prevalence of HANDs, suggesting ongoing pathological process even when viral replication is suppressed. In this study, we investigated how HIV-1 protein Nef secreted in extracellular vesicles (exNef) impairs neuronal functionality. ExNef were rapidly taken up by neural cells in vitro, reducing the abundance of ABC transporter A1 (ABCA1) and thus cholesterol efflux and increasing the abundance and modifying lipid rafts in neuronal plasma membranes. ExNef caused a redistribution of amyloid precursor protein (APP) and Tau to lipid rafts and increased the abundance of these proteins, as well as of Aβ42 ExNef further potentiated phosphorylation of Tau and activation of inflammatory pathways. These changes were accompanied by neuronal functional impairment. Disruption of lipid rafts with cyclodextrin reversed the phenotype. Short-term treatment of C57BL/6 mice with either purified recombinant Nef or exNef similarly resulted in reduced abundance of ABCA1 and elevated abundance of APP in brain tissue. The abundance of ABCA1 in brain tissue of HIV-infected human subjects diagnosed with HAND was lower, and the abundance of lipid rafts was higher compared with HIV-negative individuals. Levels of APP and Tau in brain tissue correlated with the abundance of Nef. Thus, modification of neuronal cholesterol trafficking and of lipid rafts by Nef may contribute to early stages of neurodegeneration and pathogenesis in HAND.
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Affiliation(s)
| | | | | | - Anh Hoang
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Hann Low
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Tatiana Pushkarsky
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, D.C., USA
| | - Ying Fu
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Irena Carmichael
- Department of Micro Imaging, Monash University, Melbourne, Victoria, Australia
| | - Andrew F Hill
- Department of Biochemistry and Genetics, Louisiana Trobe Institute for Molecular Science, Louisiana Trobe University, Bundoora, Victoria, Australia
| | - Andrew J Murphy
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, D.C., USA
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
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5
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Mukhamedova N, Huynh K, Low H, Meikle PJ, Sviridov D. Isolation of Lipid Rafts from Cultured Mammalian Cells and Their Lipidomics Analysis. Bio Protoc 2020; 10:e3670. [PMID: 33659340 DOI: 10.21769/bioprotoc.3670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 04/19/2020] [Accepted: 04/23/2020] [Indexed: 11/02/2022] Open
Abstract
Lipid rafts are distinct liquid-ordered domains of plasma membranes of most eukaryotic cells providing platform for signaling pathways. Lipid composition of rafts is critical for their structural integrity and for regulation of signaling pathways originating from rafts. Here we provide a protocol to isolate lipid rafts from cultured human and animal cells and comprehensively analyse their lipid composition.
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Affiliation(s)
| | - Kevin Huynh
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Hann Low
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Peter J Meikle
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
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6
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Abstract
Lipid rafts regulate the initiation of cellular metabolic and signaling pathways by organizing the pathway components in ordered microdomains on the cell surface. Cellular responses regulated by lipid rafts range from physiological to pathological, and the success of a therapeutic approach targeting "pathological" lipid rafts depends on the ability of a remedial agent to recognize them and disrupt pathological lipid rafts without affecting normal raft-dependent cellular functions. In this article, concluding the Thematic Review Series on Biology of Lipid Rafts, we review current experimental therapies targeting pathological lipid rafts, including examples of inflammarafts and clusters of apoptotic signaling molecule-enriched rafts. The corrective approaches include regulation of cholesterol and sphingolipid metabolism and membrane trafficking by using HDL and its mimetics, LXR agonists, ABCA1 overexpression, and cyclodextrins, as well as a more targeted intervention with apoA-I binding protein. Among others, we highlight the design of antagonists that target inflammatory receptors only in their activated form of homo- or heterodimers, when receptor dimerization occurs in pathological lipid rafts. Other therapies aim to promote raft-dependent physiological functions, such as augmenting caveolae-dependent tissue repair. The overview of this highly dynamic field will provide readers with a view on the emerging concept of targeting lipid rafts as a therapeutic strategy.jlr;61/5/687/F1F1f1.
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Affiliation(s)
- Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | | | - Yury I. Miller
- Department of Medicine,University of California, San Diego, La Jolla, CA
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7
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Abstract
Lipid rafts, solid regions of the plasma membrane enriched in cholesterol and glycosphingolipids, are essential parts of a cell. Functionally, lipid rafts present a platform that facilitates interaction of cells with the outside world. However, the unique properties of lipid rafts required to fulfill this function at the same time make them susceptible to exploitation by pathogens. Many steps of pathogen interaction with host cells, and sometimes all steps within the entire lifecycle of various pathogens, rely on host lipid rafts. Such steps as binding of pathogens to the host cells, invasion of intracellular parasites into the cell, the intracellular dwelling of parasites, microbial assembly and exit from the host cell, and microbe transfer from one cell to another all involve lipid rafts. Interaction also includes modification of lipid rafts in host cells, inflicted by pathogens from both inside and outside the cell, through contact or remotely, to advance pathogen replication, to utilize cellular resources, and/or to mitigate immune response. Here, we provide a systematic overview of how and why pathogens interact with and exploit host lipid rafts, as well as the consequences of this interaction for the host, locally and systemically, and for the microbe. We also raise the possibility of modulation of lipid rafts as a therapeutic approach against a variety of infectious agents.
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Affiliation(s)
- Michael I Bukrinsky
- Department of Microbiology, Immunology, and Tropical Medicine,George Washington University School of Medicine and Health Science, Washington, DC 20037
| | | | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne 3004, Australia. mailto:
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8
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Ursino GM, Fu Y, Cottle DL, Mukhamedova N, Jones LK, Low H, Tham MS, Gan WJ, Mellett NA, Das PP, Weir JM, Ditiatkovski M, Fynch S, Thorn P, Thomas HE, Meikle PJ, Parkington HC, Smyth IM, Sviridov D. ABCA12 regulates insulin secretion from β-cells. EMBO Rep 2020; 21:e48692. [PMID: 32072744 DOI: 10.15252/embr.201948692] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 12/12/2019] [Accepted: 01/08/2020] [Indexed: 12/18/2022] Open
Abstract
Dysregulation of lipid homeostasis is intimately associated with defects in insulin secretion, a key feature of type 2 diabetes. Here, we explore the role of the putative lipid transporter ABCA12 in regulating insulin secretion from β-cells. Mice with β-cell-specific deletion of Abca12 display impaired glucose-stimulated insulin secretion and eventual islet inflammation and β-cell death. ABCA12's action in the pancreas is independent of changes in the abundance of two other cholesterol transporters, ABCA1 and ABCG1, or of changes in cellular cholesterol or ceramide content. Instead, loss of ABCA12 results in defects in the genesis and fusion of insulin secretory granules and increases in the abundance of lipid rafts at the cell membrane. These changes are associated with dysregulation of the small GTPase CDC42 and with decreased actin polymerisation. Our findings establish a new, pleiotropic role for ABCA12 in regulating pancreatic lipid homeostasis and insulin secretion.
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Affiliation(s)
- Gloria M Ursino
- Department of Anatomy and Developmental Biology, Department of Biochemistry and Molecular Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Vic., Australia
| | - Ying Fu
- Baker Heart and Diabetes Institute, Melbourne, Vic., Australia
| | - Denny L Cottle
- Department of Anatomy and Developmental Biology, Department of Biochemistry and Molecular Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Vic., Australia
| | | | - Lynelle K Jones
- Department of Anatomy and Developmental Biology, Department of Biochemistry and Molecular Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Vic., Australia
| | - Hann Low
- Baker Heart and Diabetes Institute, Melbourne, Vic., Australia
| | - Ming Shen Tham
- Department of Anatomy and Developmental Biology, Department of Biochemistry and Molecular Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Vic., Australia
| | - Wan Jun Gan
- Charles Perkins Centre, Camperdown, NSW, Australia
| | | | - Partha P Das
- Department of Anatomy and Developmental Biology, Department of Biochemistry and Molecular Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Vic., Australia
| | | | | | - Stacey Fynch
- St Vincent's Institute, Fitzroy, Vic., Australia
| | - Peter Thorn
- Charles Perkins Centre, Camperdown, NSW, Australia
| | | | - Peter J Meikle
- Baker Heart and Diabetes Institute, Melbourne, Vic., Australia
| | - Helena C Parkington
- Department of Physiology, Neuroscience Discovery Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Vic., Australia
| | - Ian M Smyth
- Department of Anatomy and Developmental Biology, Department of Biochemistry and Molecular Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Vic., Australia
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Vic., Australia
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9
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Lake NJ, Taylor RL, Trahair H, Harikrishnan KN, Curran JE, Almeida M, Kulkarni H, Mukhamedova N, Hoang A, Low H, Murphy AJ, Johnson MP, Dyer TD, Mahaney MC, Göring HHH, Moses EK, Sviridov D, Blangero J, Jowett JBM, Bozaoglu K. TRAK2, a novel regulator of ABCA1 expression, cholesterol efflux and HDL biogenesis. Eur Heart J 2019; 38:3579-3587. [PMID: 28655204 DOI: 10.1093/eurheartj/ehx315] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 05/25/2017] [Indexed: 12/28/2022] Open
Abstract
Aims The recent failures of HDL-raising therapies have underscored our incomplete understanding of HDL biology. Therefore there is an urgent need to comprehensively investigate HDL metabolism to enable the development of effective HDL-centric therapies. To identify novel regulators of HDL metabolism, we performed a joint analysis of human genetic, transcriptomic, and plasma HDL-cholesterol (HDL-C) concentration data and identified a novel association between trafficking protein, kinesin binding 2 (TRAK2) and HDL-C concentration. Here we characterize the molecular basis of the novel association between TRAK2 and HDL-cholesterol concentration. Methods and results Analysis of lymphocyte transcriptomic data together with plasma HDL from the San Antonio Family Heart Study (n = 1240) revealed a significant negative correlation between TRAK2 mRNA levels and HDL-C concentration, HDL particle diameter and HDL subspecies heterogeneity. TRAK2 siRNA-mediated knockdown significantly increased cholesterol efflux to apolipoprotein A-I and isolated HDL from human macrophage (THP-1) and liver (HepG2) cells by increasing the mRNA and protein expression of the cholesterol transporter ATP-binding cassette, sub-family A member 1 (ABCA1). The effect of TRAK2 knockdown on cholesterol efflux was abolished in the absence of ABCA1, indicating that TRAK2 functions in an ABCA1-dependent efflux pathway. TRAK2 knockdown significantly increased liver X receptor (LXR) binding at the ABCA1 promoter, establishing TRAK2 as a regulator of LXR-mediated transcription of ABCA1. Conclusion We show, for the first time, that TRAK2 is a novel regulator of LXR-mediated ABCA1 expression, cholesterol efflux, and HDL biogenesis. TRAK2 may therefore be an important target in the development of anti-atherosclerotic therapies.
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Affiliation(s)
- Nicole J Lake
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.,Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC 3052, Australia
| | - Rachael L Taylor
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - Hugh Trahair
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - K N Harikrishnan
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.,Department of Pathology, University of Melbourne, Grattan Street, Parkville, VIC 3010, Australia
| | - Joanne E Curran
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Marcio Almeida
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Hemant Kulkarni
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Nigora Mukhamedova
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - Anh Hoang
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - Hann Low
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - Andrew J Murphy
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - Matthew P Johnson
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Thomas D Dyer
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Michael C Mahaney
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Harald H H Göring
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Eric K Moses
- University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia.,Curtin University, Kent St, Bentley, WA 6102, Australia
| | - Dmitri Sviridov
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - John Blangero
- South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, One West University Blvd. Brownsville, Texas 78520, USA
| | - Jeremy B M Jowett
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - Kiymet Bozaoglu
- Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.,Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, 50 Flemington Road, Parkville,VIC 3052, Australia
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10
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Low H, Hoang A, Pushkarsky T, Dubrovsky L, Dewar E, Di Yacovo MS, Mukhamedova N, Cheng L, Downs C, Simon G, Saumoy M, Hill AF, Fitzgerald ML, Nestel P, Dart A, Hoy J, Bukrinsky M, Sviridov D. HIV disease, metabolic dysfunction and atherosclerosis: A three year prospective study. PLoS One 2019; 14:e0215620. [PMID: 30998801 PMCID: PMC6472799 DOI: 10.1371/journal.pone.0215620] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/04/2019] [Indexed: 12/19/2022] Open
Abstract
HIV infection is known to be associated with cardiometabolic abnormalities; here we investigated the progression and causes of these abnormalities. Three groups of participants were recruited: HIV-negative subjects and two groups of treatment-naïve HIV-positive subjects, one group initiating antiretroviral treatment, the other remaining untreated. Intima-media thickness (cIMT) increased in HIV-positive untreated group compared to HIV-negative group, but treatment mitigated the difference. We found no increase in diabetes-related metabolic markers or in the level of inflammation in any of the groups. Total cholesterol, low density lipoprotein cholesterol and apoB levels were lower in HIV-positive groups, while triglyceride and Lp(a) levels did not differ between the groups. We found a statistically significant negative association between viral load and plasma levels of total cholesterol, LDL cholesterol, HDL cholesterol, apoA-I and apoB. HIV-positive patients had hypoalphalipoproteinemia at baseline, and we found a redistribution of sub-populations of high density lipoprotein (HDL) particles with increased proportion of smaller HDL in HIV-positive untreated patients, which may result from increased levels of plasma cholesteryl ester transfer protein in this group. HDL functionality declined in the HIV-negative and HIV-positive untreated groups, but not in HIV-positive treated group. We also found differences between HIV-positive and negative groups in plasma abundance of several microRNAs involved in lipid metabolism. Our data support a hypothesis that cardiometabolic abnormalities in HIV infection are caused by HIV and that antiretroviral treatment itself does not influence key cardiometabolic parameters, but mitigates those affected by HIV.
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Affiliation(s)
- Hann Low
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Anh Hoang
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Tatiana Pushkarsky
- Department of Microbiology, Immunology and Tropical Diseases, George Washington University, Washington, DC, United States of America
| | - Larisa Dubrovsky
- Department of Microbiology, Immunology and Tropical Diseases, George Washington University, Washington, DC, United States of America
| | - Elizabeth Dewar
- The Heart Centre, Alfred Hospital, Melbourne, VIC, Australia
| | - Maria-Silvana Di Yacovo
- HIV and STD Unit, Infectious Disease Service, Hospital Universitari de Bellvitge, Instituto de Investigación Biomédica de Bellvitge, Hospitalet de Llobregat, Barcelona, Spain
| | | | - Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
| | - Catherine Downs
- Department of Infectious Diseases, Alfred Hospital, Melbourne, VIC, Australia
| | - Gary Simon
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC, United States of America
| | - Maria Saumoy
- HIV and STD Unit, Infectious Disease Service, Hospital Universitari de Bellvitge, Instituto de Investigación Biomédica de Bellvitge, Hospitalet de Llobregat, Barcelona, Spain
| | - Andrew F. Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
| | - Michael L. Fitzgerald
- Lipid Metabolism Unit, Centre for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Paul Nestel
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Anthony Dart
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- The Heart Centre, Alfred Hospital, Melbourne, VIC, Australia
| | - Jennifer Hoy
- Department of Infectious Diseases, Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, Monash University, Melbourne, VIC, Australia
| | - Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Diseases, George Washington University, Washington, DC, United States of America
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- * E-mail:
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11
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Sviridov D, Mukhamedova N. Cdc42 - A tryst between host cholesterol metabolism and infection. Small GTPases 2018; 9:237-241. [PMID: 27580266 DOI: 10.1080/21541248.2016.1223533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Emerging evidence points to an important connection between pathogenesis of intracellular infections and host cholesterol metabolism. In our study we demonstrated that human cytomegalovirus exploits host small GTPase Cdc42 to hijack cellular cholesterol efflux pathway. It appears that the virus uses host machinery to stimulate cholesterol efflux by modifying lipid rafts and altering properties of plasma membrane, but the altered pathway is controlled by the viral protein US28 instead of the host ATP binding cassette transporter A1. We speculate that virus-controlled remodeling of plasma membrane facilitates immune evasion, exocytosis of viral proteins and cell-to-cell transmission of human cytomegalovirus. These mechanisms may be not unique for the cytomegalovirus and subverting reverse cholesterol transport pathway may be a generic mechanism used by pathogens to alter properties of host plasma membrane adapting it for their purposes-to hide and disseminate.
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Affiliation(s)
- Dmitri Sviridov
- a Baker IDI Heart and Diabetes Institute , Melbourne , Australia
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12
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Sviridov D, Mukhamedova N. Cholesterol: a dark horse in signalling race. Curr Opin Lipidol 2017; 28:385-386. [PMID: 28700381 DOI: 10.1097/mol.0000000000000435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
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13
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Mukhamedova N, Hoang A, Cui HL, Carmichael I, Fu Y, Bukrinsky M, Sviridov D. Small GTPase ARF6 Regulates Endocytic Pathway Leading to Degradation of ATP-Binding Cassette Transporter A1. Arterioscler Thromb Vasc Biol 2016; 36:2292-2303. [PMID: 27758770 DOI: 10.1161/atvbaha.116.308418] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/19/2016] [Indexed: 11/16/2022]
Abstract
OBJECTIVE ABCA1 (ATP-binding cassette transporter A1) is the principal protein responsible for cellular cholesterol efflux. Abundance and functionality of ABCA1 is regulated both transcriptionally and post-translationally, with endocytosis of ABCA1 being an important element of post-translational regulation. Functional ABCA1 resides on the plasma membrane but can be internalized and either degraded or recycled back to the plasma membrane. The interaction between the degradative and recycling pathways determines the abundance of ABCA1 and may contribute to the efflux of intracellular cholesterol. APPROACH AND RESULTS Here, we show that the principal pathway responsible for the internalization of ABCA1 leading to its degradation in macrophages is ARF6-dependent endocytic pathway. This pathway was predominant in the regulation of ABCA1 abundance and efflux of plasma membrane cholesterol. Conversely, the efflux of intracellular cholesterol was predominantly controlled by ARF6-independent pathways, and inhibition of ARF6 shifted ABCA1 into recycling endosomes enhancing efflux of intracellular cholesterol. CONCLUSIONS We conclude that ARF6-dependent pathway is the predominant route responsible for the ABCA1 internalization and degradation, whereas ARF6-independent endocytic pathways may contribute to ABCA1 recycling and efflux of intracellular cholesterol.
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Affiliation(s)
- Nigora Mukhamedova
- From the Department of Lipoproteins and Atherosclerosis, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.M., A.H., H.L.C., I.C., Y.F., D.S.); Department of Medicine, Karolinska Institute, Stockholm, Sweden (H.L.C.); and Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC (M.B.)
| | - Anh Hoang
- From the Department of Lipoproteins and Atherosclerosis, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.M., A.H., H.L.C., I.C., Y.F., D.S.); Department of Medicine, Karolinska Institute, Stockholm, Sweden (H.L.C.); and Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC (M.B.)
| | - Huanhuan L Cui
- From the Department of Lipoproteins and Atherosclerosis, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.M., A.H., H.L.C., I.C., Y.F., D.S.); Department of Medicine, Karolinska Institute, Stockholm, Sweden (H.L.C.); and Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC (M.B.)
| | - Irena Carmichael
- From the Department of Lipoproteins and Atherosclerosis, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.M., A.H., H.L.C., I.C., Y.F., D.S.); Department of Medicine, Karolinska Institute, Stockholm, Sweden (H.L.C.); and Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC (M.B.)
| | - Ying Fu
- From the Department of Lipoproteins and Atherosclerosis, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.M., A.H., H.L.C., I.C., Y.F., D.S.); Department of Medicine, Karolinska Institute, Stockholm, Sweden (H.L.C.); and Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC (M.B.)
| | - Michael Bukrinsky
- From the Department of Lipoproteins and Atherosclerosis, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.M., A.H., H.L.C., I.C., Y.F., D.S.); Department of Medicine, Karolinska Institute, Stockholm, Sweden (H.L.C.); and Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC (M.B.)
| | - Dmitri Sviridov
- From the Department of Lipoproteins and Atherosclerosis, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.M., A.H., H.L.C., I.C., Y.F., D.S.); Department of Medicine, Karolinska Institute, Stockholm, Sweden (H.L.C.); and Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC (M.B.).
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14
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Low H, Mukhamedova N, Cui HL, McSharry BP, Avdic S, Hoang A, Ditiatkovski M, Liu Y, Fu Y, Meikle PJ, Blomberg M, Polyzos KA, Miller WE, Religa P, Bukrinsky M, Soderberg-Naucler C, Slobedman B, Sviridov D. Cytomegalovirus Restructures Lipid Rafts via a US28/CDC42-Mediated Pathway, Enhancing Cholesterol Efflux from Host Cells. Cell Rep 2016; 16:186-200. [PMID: 27320924 DOI: 10.1016/j.celrep.2016.05.070] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 04/07/2016] [Accepted: 05/17/2016] [Indexed: 01/30/2023] Open
Abstract
Cytomegalovirus (HCMV) contains cholesterol, but how HCMV interacts with host cholesterol metabolism is unknown. We found that, in human fibroblasts, HCMV infection increased the efflux of cellular cholesterol, despite reducing the abundance of ABCA1. Mechanistically, viral protein US28 was acting through CDC42, rearranging actin microfilaments, causing association of actin with lipid rafts, and leading to a dramatic change in the abundance and/or structure of lipid rafts. These changes displaced ABCA1 from the cell surface but created new binding sites for apolipoprotein A-I, resulting in enhanced cholesterol efflux. The changes also reduced the inflammatory response in macrophages. HCMV infection modified the host lipidome profile and expression of several genes and microRNAs involved in cholesterol metabolism. In mice, murine CMV infection elevated plasma triglycerides but did not affect the level and functionality of high-density lipoprotein. Thus, HCMV, through its protein US28, reorganizes lipid rafts and disturbs cell cholesterol metabolism.
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Affiliation(s)
- Hann Low
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | | | - Huanhuan L Cui
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia; Department of Medicine, Karolinska Institute, Stockholm 171 76, Sweden
| | - Brian P McSharry
- Discipline of Infectious Diseases and Immunology, University of Sydney, NSW 2006, Australia
| | - Selmir Avdic
- Discipline of Infectious Diseases and Immunology, University of Sydney, NSW 2006, Australia
| | - Anh Hoang
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | | | - Yingying Liu
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Ying Fu
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Martin Blomberg
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | | | - William E Miller
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Piotr Religa
- Department of Medicine, Karolinska Institute, Stockholm 171 76, Sweden
| | - Michael Bukrinsky
- GW School of Medicine and Health Sciences, George Washington University, Washington, DC 20037, USA
| | | | - Barry Slobedman
- Discipline of Infectious Diseases and Immunology, University of Sydney, NSW 2006, Australia
| | - Dmitri Sviridov
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia.
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15
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Cui HL, Ditiatkovski M, Kesani R, Bobryshev YV, Liu Y, Geyer M, Mukhamedova N, Bukrinsky M, Sviridov D. HIV protein Nef causes dyslipidemia and formation of foam cells in mouse models of atherosclerosis. FASEB J 2014; 28:2828-39. [PMID: 24642731 DOI: 10.1096/fj.13-246876] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Patients with HIV are at an increased risk of cardiovascular disease. In this study we investigated the effect of Nef, a secreted HIV protein responsible for the impairment of cholesterol efflux, on the development of atherosclerosis in two animal models. ApoE(-/-) mice fed a high-fat diet and C57BL/6 mice fed a high-fat, high-cholesterol diet were injected with recombinant Nef (40 ng/injection) or vehicle, and the effects of Nef on development of atherosclerosis, inflammation, and dyslipidemia were assessed. In apoE(-/-) mice, Nef significantly increased the size of atherosclerotic lesions and caused vessel remodeling. Nef caused elevation of total cholesterol and triglyceride levels in the plasma while reducing high-density lipoprotein cholesterol levels. These changes were accompanied by a reduction of ABCA1 abundance in the liver, but not in the vessels. In C57BL/6 mice, Nef caused a significant number of lipid-laden macrophages presented in adventitia of the vessels; these cells were absent from the vessels of control mice. Nef caused sharp elevations of plasma triglyceride levels and body weight. Taken together, our findings suggest that Nef causes dyslipidemia and accumulation of cholesterol in macrophages within the vessel wall, supporting the role of Nef in pathogenesis of atherosclerosis in HIV-infected patients.-Cui, H. L., Ditiatkovski, M., Kesani, R., Bobryshev, Y. V., Liu, Y., Geyer, M., Mukhamedova, N., Bukrinsky, M., Sviridov, D. HIV protein Nef causes dyslipidemia and formation of foam cells in mouse models of atherosclerosis.
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Affiliation(s)
- Huanhuan L Cui
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | | | - Rajitha Kesani
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Yuri V Bobryshev
- School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Yingying Liu
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Matthias Geyer
- Center for Advanced European Studies and Research (CAESAR), Bonn, Germany; and
| | | | - Michael Bukrinsky
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, District of Columbia, USA
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia;
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16
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Cui HL, Guo B, Scicluna B, Coleman BM, Lawson VA, Ellett L, Meikle PJ, Bukrinsky M, Mukhamedova N, Sviridov D, Hill AF. Prion infection impairs cholesterol metabolism in neuronal cells. J Biol Chem 2013; 289:789-802. [PMID: 24280226 PMCID: PMC3887205 DOI: 10.1074/jbc.m113.535807] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Conversion of prion protein (PrP(C)) into a pathological isoform (PrP(Sc)) during prion infection occurs in lipid rafts and is dependent on cholesterol. Here, we show that prion infection increases the abundance of cholesterol transporter, ATP-binding cassette transporter type A1 (ATP-binding cassette transporter type A1), but reduces cholesterol efflux from neuronal cells leading to the accumulation of cellular cholesterol. Increased abundance of ABCA1 in prion disease was confirmed in prion-infected mice. Mechanistically, conversion of PrP(C) to the pathological isoform led to PrP(Sc) accumulation in rafts, displacement of ABCA1 from rafts and the cell surface, and enhanced internalization of ABCA1. These effects were abolished with reversal of prion infection or by loading cells with cholesterol. Stimulation of ABCA1 expression with liver X receptor agonist or overexpression of heterologous ABCA1 reduced the conversion of prion protein into the pathological form upon infection. These findings demonstrate a reciprocal connection between prion infection and cellular cholesterol metabolism, which plays an important role in the pathogenesis of prion infection in neuronal cells.
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Affiliation(s)
- Huanhuan L Cui
- From the Baker Heart and Diabetes Institute, Melbourne, Victoria 8008, Australia
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17
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Fu Y, Mukhamedova N, Ip S, D'Souza W, Henley KJ, DiTommaso T, Kesani R, Ditiatkovski M, Jones L, Lane RM, Jennings G, Smyth IM, Kile BT, Sviridov D. ABCA12 regulates ABCA1-dependent cholesterol efflux from macrophages and the development of atherosclerosis. Cell Metab 2013; 18:225-38. [PMID: 23931754 DOI: 10.1016/j.cmet.2013.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 03/05/2013] [Accepted: 07/02/2013] [Indexed: 11/16/2022]
Abstract
ABCA12 is involved in the transport of ceramides in skin, but it may play a wider role in lipid metabolism. We show that, in Abca12-deficient macrophages, cholesterol efflux failed to respond to activation with LXR agonists. Abca12 deficiency caused a reduction in the abundance of Abca1, Abcg1, and Lxrβ. Overexpression of Lxrβ reversed the effects. Mechanistically, Abca12 deficiency did not affect expression of genes involved in cholesterol metabolism. Instead, a physical association between Abca1, Abca12, and Lxrβ proteins was established. Abca12 deficiency enhanced interaction between Abca1 and Lxrβ and the degradation of Abca1. Overexpression of ABCA12 in HeLa-ABCA1 cells increased the abundance and stability of ABCA1. Abca12 deficiency caused an accumulation of cholesterol in macrophages and the formation of foam cells, impaired reverse cholesterol transport in vivo, and increased the development of atherosclerosis in irradiated Apoe(-/-) mice reconstituted with Apoe(-/-)Abca12(-/-) bone marrow. Thus, ABCA12 regulates the cellular cholesterol metabolism via an LXRβ-dependent posttranscriptional mechanism.
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Affiliation(s)
- Ying Fu
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
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18
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Cui HL, Grant A, Mukhamedova N, Pushkarsky T, Jennelle L, Dubrovsky L, Gaus K, Fitzgerald ML, Sviridov D, Bukrinsky M. HIV-1 Nef mobilizes lipid rafts in macrophages through a pathway that competes with ABCA1-dependent cholesterol efflux. J Lipid Res 2012; 53:696-708. [PMID: 22262807 DOI: 10.1194/jlr.m023119] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV infection, through the actions of viral accessory protein Nef, impairs activity of cholesterol transporter ABCA1, inhibiting cholesterol efflux from macrophages and elevating the risk of atherosclerosis. Nef also induces lipid raft formation. In this study, we demonstrate that these activities are tightly linked and affect macrophage function and HIV replication. Nef stimulated lipid raft formation in macrophage cell line RAW 264.7, and lipid rafts were also mobilized in HIV-1-infected human monocyte-derived macrophages. Nef-mediated transfer of cholesterol to lipid rafts competed with the ABCA1-dependent pathway of cholesterol efflux, and pharmacological inhibition of ABCA1 functionality or suppression of ABCA1 expression by RNAi increased Nef-dependent delivery of cholesterol to lipid rafts. Nef reduced cell-surface accessibility of ABCA1 and induced ABCA1 catabolism via the lysosomal pathway. Despite increasing the abundance of lipid rafts, expression of Nef impaired phagocytic functions of macrophages. The infectivity of the virus produced in natural target cells of HIV-1 negatively correlated with the level of ABCA1. These findings demonstrate that Nef-dependent inhibition of ABCA1 is an essential component of the viral replication strategy and underscore the role of ABCA1 as an innate anti-HIV factor.
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Affiliation(s)
- Huanhuan L Cui
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
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19
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Mukhamedova N, D’Souza W, Low H, Kesani R, Chimini G, Sviridov D. Global functional knockdown of ATP binding cassette transporter A1 stimulates development of atherosclerosis in apoE K/O mice. Biochem Biophys Res Commun 2011; 412:446-9. [DOI: 10.1016/j.bbrc.2011.07.113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 07/27/2011] [Indexed: 10/17/2022]
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20
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Morrow MP, Grant A, Mujawar Z, Dubrovsky L, Pushkarsky T, Kiselyeva Y, Jennelle L, Mukhamedova N, Remaley AT, Kashanchi F, Sviridov D, Bukrinsky M. Stimulation of the liver X receptor pathway inhibits HIV-1 replication via induction of ATP-binding cassette transporter A1. Mol Pharmacol 2010; 78:215-25. [PMID: 20479131 DOI: 10.1124/mol.110.065029] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cholesterol plays an important role in the HIV life cycle, and infectivity of cholesterol-depleted HIV virions is significantly impaired. Recently, we demonstrated that HIV-1, via its protein Nef, inhibits the activity of the major cellular cholesterol transporter ATP binding cassette transporter A1 (ABCA1), suggesting that the virus may use this mechanism to get access to cellular cholesterol. In this study, we investigated the effect on HIV infection of a synthetic liver X receptor (LXR) ligand, N-(2,2,2-trifluoro-ethyl)-N-[4-(2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl-ethyl)-phenyl]-benzenesulfonamide (TO-901317), which is a potent stimulator of ABCA1 expression. We demonstrate that TO-901317 restores cholesterol efflux from HIV-infected T lymphocytes and macrophages. TO-901317 potently suppressed HIV-1 replication in both cell types and inhibited HIV-1 replication in ex vivo cultured lymphoid tissue and in RAG-hu mice infected in vivo. This anti-HIV activity was dependent on ABCA1, because the effect of the drug was significantly reduced in ABCA1-defective T cells from a patient with Tangier disease, and RNA interference-mediated inhibition of ABCA1 expression eliminated the effect of TO-901317 on HIV-1 replication. TO-901317-mediated inhibition of HIV replication was due to reduced virus production and reduced infectivity of produced virions. The infectivity defect was in part due to reduced fusion activity of the virions, which was directly linked to reduced viral cholesterol. These results describe a novel approach to inhibiting HIV infection by stimulating ABCA1 expression.
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21
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Crowe SM, Westhorpe CLV, Mukhamedova N, Jaworowski A, Sviridov D, Bukrinsky M. The macrophage: the intersection between HIV infection and atherosclerosis. J Leukoc Biol 2009; 87:589-98. [PMID: 19952353 DOI: 10.1189/jlb.0809580] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
HIV-infected individuals are at increased risk of coronary artery disease (CAD) with underlying mechanisms including chronic immune activation and inflammation secondary to HIV-induced microbial translocation and low-grade endotoxemia; direct effects of HIV and viral proteins on macrophage cholesterol metabolism; and dyslipidemia related to HIV infection and specific antiretroviral therapies. Monocytes are the precursors of the lipid-laden foam cells within the atherosclerotic plaque and produce high levels of proinflammatory cytokines such as IL-6. The minor CD14+/CD16+ "proinflammatory" monocyte subpopulation is preferentially susceptible to HIV infection and may play a critical role in the pathogenesis of HIV-related CAD. In this review, the central role of monocytes/macrophages in HIV-related CAD and the importance of inflammation and cholesterol metabolism are discussed.
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Affiliation(s)
- Suzanne M Crowe
- Centre for Virology, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004, Australia.
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Hacking D, Hilton A, Ip S, Mukhamedova N, Meikle P, Ellis S, Satterly K, Collinge J, de Graaf C, Bahlo M, Sviridov D, Kile B, Hilton D, Smyth I. 06-P009 A role for Abca12 in regulating terminal differentiation and lipid balance in the developing epidermis. Mech Dev 2009. [DOI: 10.1016/j.mod.2009.06.235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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23
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Brace R, Williams M, Sviridov D, Mukhamedova N, McCormick S. Abstract: 1480 INFLUENCE OF ABCA1 PROMOTER HAPLOTYPES ON A NOVEL R1068H MUTATION. ATHEROSCLEROSIS SUPP 2009. [DOI: 10.1016/s1567-5688(09)70443-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sviridov D, Tchoua U, Mukhamedova N, Niesor E, Mizrahi J, Maugeais C. Abstract: 1061 CHOLESTERYL ESTER TRANSFER PROTEIN INHIBITION AND REVERSE CHOLESTEROL TRANSPORT. ATHEROSCLEROSIS SUPP 2009. [DOI: 10.1016/s1567-5688(09)70172-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sviridov D, D'Souza W, Murphy A, Mukhamedova N, Chin-Dusting J, Hacking D, Hilton D, Kile B, Smyth I. Abstract: 1042 ABCA12 – A NEW REGULATOR OF CELLULAR LIPID METABOLISM. ATHEROSCLEROSIS SUPP 2009. [DOI: 10.1016/s1567-5688(09)70394-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Shaw JA, Bobik A, Murphy A, Kanellakis P, Blombery P, Mukhamedova N, Woollard K, Lyon S, Sviridov D, Dart AM. Infusion of reconstituted high-density lipoprotein leads to acute changes in human atherosclerotic plaque. Circ Res 2008; 103:1084-91. [PMID: 18832751 DOI: 10.1161/circresaha.108.182063] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Studies have shown a reduction in plaque volume and change in plaque ultrasound characteristics after 4 infusions of reconstituted high-density lipoprotein (rHDL). Whether rHDL infusion leads to acute changes in plaque characteristics in humans is not known. Patients with claudication scheduled for percutaneous superficial femoral artery revascularization were randomized to receive 1 intravenous infusion of either placebo or rHDL (80 mg/kg given over 4 hours). Five to 7 days following the infusion, patients returned and revascularization was performed including atherectomy to excise plaque from the superficial femoral artery. Twenty patients (17 males) average age, 68+/-10 years (mean+/-SD) were recruited. Eleven patients had a history of documented coronary artery disease, all patients were on aspirin, and 18 were on statins. Ten of the patients received rHDL and 10 placebo. There was significantly less vascular cell adhesion molecule-1 expression (28+/-3% versus 50+/-3%; P<0.05) and a reduction in lipid content in the plaque of HDL-treated subjects compared to placebo. The level of HDL cholesterol increased by 20% after infusion of rHDL and the capacity of apolipoprotein B-depleted plasma to support cholesterol efflux increased. Intravenous infusion of a single dose of reconstituted HDL led to acute changes in plaque characteristics with a reduction in lipid content, macrophage size, and measures of inflammation. These changes may contribute to the cardioprotective effects of HDL.
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Affiliation(s)
- James A Shaw
- Department of Cardiovascular Medicine, Alfred Hospital/Baker IDI Heart and Diabetes Institute, PO Box 6492, St Kilda Rd Central 8008, Australia.
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Smyth I, Hacking DF, Hilton AA, Mukhamedova N, Meikle PJ, Ellis S, Satterley K, Collinge JE, de Graaf CA, Bahlo M, Sviridov D, Kile BT, Hilton DJ. A mouse model of harlequin ichthyosis delineates a key role for Abca12 in lipid homeostasis. PLoS Genet 2008; 4:e1000192. [PMID: 18802465 PMCID: PMC2529452 DOI: 10.1371/journal.pgen.1000192] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 08/06/2008] [Indexed: 11/19/2022] Open
Abstract
Harlequin Ichthyosis (HI) is a severe and often lethal hyperkeratotic skin disease caused by mutations in the ABCA12 transport protein. In keratinocytes, ABCA12 is thought to regulate the transfer of lipids into small intracellular trafficking vesicles known as lamellar bodies. However, the nature and scope of this regulation remains unclear. As part of an original recessive mouse ENU mutagenesis screen, we have identified and characterised an animal model of HI and showed that it displays many of the hallmarks of the disease including hyperkeratosis, loss of barrier function, and defects in lipid homeostasis. We have used this model to follow disease progression in utero and present evidence that loss of Abca12 function leads to premature differentiation of basal keratinocytes. A comprehensive analysis of lipid levels in mutant epidermis demonstrated profound defects in lipid homeostasis, illustrating for the first time the extent to which Abca12 plays a pivotal role in maintaining lipid balance in the skin. To further investigate the scope of Abca12's activity, we have utilised cells from the mutant mouse to ascribe direct transport functions to the protein and, in doing so, we demonstrate activities independent of its role in lamellar body function. These cells have severely impaired lipid efflux leading to intracellular accumulation of neutral lipids. Furthermore, we identify Abca12 as a mediator of Abca1-regulated cellular cholesterol efflux, a finding that may have significant implications for other diseases of lipid metabolism and homeostasis, including atherosclerosis.
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Affiliation(s)
- Ian Smyth
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia.
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Rajinda Kekulawala J, Murphy A, D’Souza W, Wai C, Chin-Dusting J, Kingwell B, Sviridov D, Mukhamedova N. Impact of freezing on high-density lipoprotein functionality. Anal Biochem 2008; 379:213-5. [DOI: 10.1016/j.ab.2008.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 05/04/2008] [Indexed: 11/29/2022]
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Mukhamedova N, Escher G, D'Souza W, Tchoua U, Grant A, Krozowski Z, Bukrinsky M, Sviridov D. Enhancing apolipoprotein A-I-dependent cholesterol efflux elevates cholesterol export from macrophages in vivo. J Lipid Res 2008; 49:2312-22. [PMID: 18622028 DOI: 10.1194/jlr.m800095-jlr200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eight proteins potentially involved in cholesterol efflux [ABCA1, ABCG1, CYP27A1, phospholipid transfer protein (PLTP), scavenger receptor type BI (SR-BI), caveolin-1, cholesteryl ester transfer protein, and apolipoprotein A-I (apoA-I)] were overexpressed alone or in combination in RAW 264.7 macrophages. When apoA-I was used as an acceptor, overexpression of the combination of ABCA1, CYP27A1, PLTP, and SR-BI (Combination I) enhanced the efflux by 4.3-fold. It was established that the stimulation of efflux was due to increased abundance of ABCA1 and increased apoA-I binding to non-ABCA1 sites on macrophages. This combination caused only a small increase of the efflux to isolated HDL. When HDL was used as an acceptor, overexpression of caveolin-1 or a combination of caveolin-1 and SR-BI (Combination II) was the most active, doubling the efflux to HDL, without affecting the efflux to apoA-I. When tested in the in vivo mouse model of cholesterol efflux, overexpression of ABCA1 and Combination I elevated cholesterol export from macrophages to plasma, liver, and feces, whereas overexpression of caveolin-1 or Combination II did not have an effect. We conclude that pathways of cholesterol efflux using apoA-I as an acceptor make a predominant contribution to cholesterol export from macrophages in vivo.
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Murphy AJ, Woollard KJ, Hoang A, Mukhamedova N, Stirzaker RA, McCormick SPA, Remaley AT, Sviridov D, Chin-Dusting J. High-density lipoprotein reduces the human monocyte inflammatory response. Arterioscler Thromb Vasc Biol 2008; 28:2071-7. [PMID: 18617650 DOI: 10.1161/atvbaha.108.168690] [Citation(s) in RCA: 339] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Whereas the anti-inflammatory effects of high-density lipoprotein (HDL) on endothelial cells are well described, such effects on monocytes are less studied. METHODS AND RESULTS Human monocytes were isolated from whole blood followed by assessment of CD11b activation/expression and cell adhesion under shear-flow. HDL caused a dose-dependent reduction in the activation of CD11b induced by PMA or receptor-dependent agonists. The constituent of HDL responsible for the antiinflammatory effects on CD11b activation was found to be apolipoprotein A-I (apoA-I). Cyclodextrin, but not cyclodextrin/cholesterol complex, also inhibited PMA-induced CD11b activation implicating cholesterol efflux as the main mechanism. This was further confirmed with the demonstration that cholesterol content of lipid rafts diminished after treatment with the cholesterol acceptors. Blocking ABCA1 with an anti-ABCA1 antibody abolished the effect of apoA-I. Furthermore, monocytes derived from a Tangier disease patient definitively confirmed the requirement of ABCA1 in apoA-I-mediated CD11b inhibition. The antiinflammatory effects of apoA-I were also observed in functional models including cell adhesion to an endothelial cell monolayer, monocytic spreading under shear flow, and transmigration. CONCLUSIONS HDL and apoA-I exhibit an antiinflammatory effect on human monocytes by inhibiting activation of CD11b. ApoA-I acts through ABCA1, whereas HDL may act through several receptors.
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Affiliation(s)
- Andrew J Murphy
- Laboratories of Vascular Pharmacology, Research Institute, Melbourne, Victoria, Australia
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Sviridov D, Mukhamedova N, T. Remaley A, Chin-Dusting J, Nestel P. Antiatherogenic Functionality of High Density Lipoprotein: How Much versus How Gooden-subtitle=. J Atheroscler Thromb 2008; 15:52-62. [DOI: 10.5551/jat.e571] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Tchoua U, D'Souza W, Mukhamedova N, Blum D, Niesor E, Mizrahi J, Maugeais C, Sviridov D. The effect of cholesteryl ester transfer protein overexpression and inhibition on reverse cholesterol transport. Cardiovasc Res 2007; 77:732-9. [DOI: 10.1093/cvr/cvm087] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Mukhamedova N, Fu Y, Bukrinsky M, Remaley AT, Sviridov D. The Role of Different Regions of ATP-Binding Cassette Transporter A1 in Cholesterol Efflux. Biochemistry 2007; 46:9388-98. [PMID: 17655203 DOI: 10.1021/bi700473t] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ABCA1 is a key element of cholesterol efflux, but the mechanism of ABCA1-dependent cholesterol efflux is still unclear. Monoclonal antibodies against ABCA1 were used to map functional domains of ABCA1. Two antibodies were directed against a fragment of the first extracellular loop of ABCA1, and the third antibody was directed against a fragment of the fourth extracellular loop. One antibody against the first loop inhibited cholesterol efflux from human macrophages without inhibiting apolipoprotein A-I (apoA-I) binding and internalization. Another antibody against the first loop inhibited apoA-I binding and internalization without inhibiting cholesterol efflux. The antibody against the fourth loop inhibited apoA-I binding to ABCA1 but enhanced cholesterol efflux from macrophages and reduced intracellular cholesterol content. This antibody also increased cholesterol efflux from HeLa cells transfected with ABCA1 but not from cells with DeltaPEST-ABCA1. The mechanism of the stimulating effect of this antibody on cholesterol efflux was found to be stabilization of ABCA1 leading to the increase in abundance of cell surface ABCA1. We conclude that a site on the first extracellular loop is required for cholesterol efflux, whereas a site on the fourth extracellular loop may be responsible for ABCA1 stability.
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Affiliation(s)
- Nigora Mukhamedova
- Baker Heart Research Institute, P.O. Box 6492, St. Kilda Road Central, Melbourne, Victoria, 8008 Australia
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Mujawar Z, Rose H, Morrow MP, Pushkarsky T, Dubrovsky L, Mukhamedova N, Fu Y, Dart A, Orenstein JM, Bobryshev YV, Bukrinsky M, Sviridov D. Human immunodeficiency virus impairs reverse cholesterol transport from macrophages. PLoS Biol 2007; 4:e365. [PMID: 17076584 PMCID: PMC1629034 DOI: 10.1371/journal.pbio.0040365] [Citation(s) in RCA: 239] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 08/31/2006] [Indexed: 12/16/2022] Open
Abstract
Several steps of HIV-1 replication critically depend on cholesterol. HIV infection is associated with profound changes in lipid and lipoprotein metabolism and an increased risk of coronary artery disease. Whereas numerous studies have investigated the role of anti-HIV drugs in lipodystrophy and dyslipidemia, the effects of HIV infection on cellular cholesterol metabolism remain uncharacterized. Here, we demonstrate that HIV-1 impairs ATP-binding cassette transporter A1 (ABCA1)-dependent cholesterol efflux from human macrophages, a condition previously shown to be highly atherogenic. In HIV-1–infected cells, this effect was mediated by Nef. Transfection of murine macrophages with Nef impaired cholesterol efflux from these cells. At least two mechanisms were found to be responsible for this phenomenon: first, HIV infection and transfection with Nef induced post-transcriptional down-regulation of ABCA1; and second, Nef caused redistribution of ABCA1 to the plasma membrane and inhibited internalization of apolipoprotein A-I. Binding of Nef to ABCA1 was required for down-regulation and redistribution of ABCA1. HIV-infected and Nef-transfected macrophages accumulated substantial amounts of lipids, thus resembling foam cells. The contribution of HIV-infected macrophages to the pathogenesis of atherosclerosis was supported by the presence of HIV-positive foam cells in atherosclerotic plaques of HIV-infected patients. Stimulation of cholesterol efflux from macrophages significantly reduced infectivity of the virions produced by these cells, and this effect correlated with a decreased amount of virion-associated cholesterol, suggesting that impairment of cholesterol efflux is essential to ensure proper cholesterol content in nascent HIV particles. These results reveal a previously unrecognized dysregulation of intracellular lipid metabolism in HIV-infected macrophages and identify Nef and ABCA1 as the key players responsible for this effect. Our findings have implications for pathogenesis of both HIV disease and atherosclerosis, because they reveal the role of cholesterol efflux impairment in HIV infectivity and suggest a possible mechanism by which HIV infection of macrophages may contribute to increased risk of atherosclerosis in HIV-infected patients. HIV1-Nef impairs ABCA1-dependent cholesterol efflux from infected macrophages, promoting the transformation of virally infected macrophages into foam cells (a condition that may put HIV patients at risk for atherosclerosis).
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Affiliation(s)
- Zahedi Mujawar
- The George Washington University, Washington, District of Columbia, United States of America
| | - Honor Rose
- Baker Heart Research Institute, Melbourne, Victoria, Australia
| | - Matthew P Morrow
- The George Washington University, Washington, District of Columbia, United States of America
| | - Tatiana Pushkarsky
- The George Washington University, Washington, District of Columbia, United States of America
| | - Larisa Dubrovsky
- The George Washington University, Washington, District of Columbia, United States of America
| | | | - Ying Fu
- Baker Heart Research Institute, Melbourne, Victoria, Australia
| | - Anthony Dart
- Baker Heart Research Institute, Melbourne, Victoria, Australia
| | - Jan M Orenstein
- The George Washington University, Washington, District of Columbia, United States of America
| | - Yuri V Bobryshev
- University of New South Wales, Sydney, New South Wales, Australia
| | - Michael Bukrinsky
- The George Washington University, Washington, District of Columbia, United States of America
- * To whom correspondence should be addressed. E-mail:
| | - Dmitri Sviridov
- Baker Heart Research Institute, Melbourne, Victoria, Australia
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Mukhamedova N, Fu Y, Sviridov D. Th-P15:222 Identification of distinct sites of ABCA1 involved in cholesterol efflux from human macrophages. ATHEROSCLEROSIS SUPP 2006. [DOI: 10.1016/s1567-5688(06)82181-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mukhamedova N, Rybalkin I, Vlasik T, Chenchik A, Kellogg D, Chen S, Siebert P. Hot start in the polymerase chain reaction brought about by the use of Taq polymerase-inhibiting anti-bodies. Atherosclerosis 1994. [DOI: 10.1016/0021-9150(94)93444-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kellogg DE, Rybalkin I, Chen S, Mukhamedova N, Vlasik T, Siebert PD, Chenchik A. TaqStart Antibody: "hot start" PCR facilitated by a neutralizing monoclonal antibody directed against Taq DNA polymerase. Biotechniques 1994; 16:1134-7. [PMID: 8074881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The specificity and DNA yield of PCRs are often improved by the "hot start" technique and analogous methods. The intent of the approach is to eliminate or prevent the generation of nonspecific PCR templates that may be synthesized at ambient temperature prior to thermal cycling. Monoclonal antibodies (MAbs) raised in mice to the purified DNA polymerase of Thermus aquaticus (Taq) were selected for their ability to reversibly block polymerase activity. The MAbs, incubated with Taq DNA polymerase and added to PCR tubes at ambient temperature, yield specific DNA fragments upon amplification when using high numbers of temperature cycles and a very low copy number of target DNA in a complex DNA background. This approach, using the TaqStart Antibody, permits the preparation of reaction mixtures at ambient temperatures without the subsequent opening of reaction tubes, use of grease or waxes, or of degradative enzymes and deoxyribonucleotide analogs.
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