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Tarling EJ, Edwards PA. Intracellular Localization of Endogenous Mouse ABCG1 Is Mimicked by Both ABCG1-L550 and ABCG1-P550-Brief Report. Arterioscler Thromb Vasc Biol 2016; 36:1323-7. [PMID: 27230131 DOI: 10.1161/atvbaha.116.307414] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/10/2016] [Indexed: 12/18/2022]
Abstract
OBJECTIVE In a recent article in Arteriosclerosis, Thrombosis, and Vascular Biology, it was reported that ATP-binding cassette transporter G1 (ABCG1) containing leucine at position 550 (ABCG1-L550) was localized to the plasma membrane, whereas ABCG1-P550 (proline at position 550) was intracellular. Because the published data on the subcellular localization of ABCG1 are controversial, we performed additional experiments to determine the importance of leucine or proline at amino acid 550. APPROACH AND RESULTS We transfected multiple cell lines (CHO-K1, Cos-7, and HEK293 [human embryonic kidney]) with untagged or FLAG-tagged ABCG1 containing either leucine or proline at position 550. Immunofluorescence studies demonstrated that in all cases, ABCG1 localized to intracellular endosomal vesicles. We also show that both ABCG1-L550 and ABCG1-P550 are equally active in both promoting the efflux of cellular cholesterol to exogenous high-density lipoprotein and in inducing the activity of sterol regulatory element-binding protein-2, presumably as a result of redistributing intracellular sterols away from the endoplasmic reticulum. Importantly, we treated nontransfected primary peritoneal macrophages with a liver X receptor agonist and demonstrate, using immunofluorescence, that although endogenous ABCG1 localizes to intracellular endosomes, none was detectable at the cell surface/plasma membrane. CONCLUSIONS ABCG1, irrespective of either a leucine or proline at position 550, is an intracellular protein that localizes to vesicles of the endosomal pathway where it functions to mobilize sterols away from the endoplasmic reticulum and out of the cell.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily G, Member 1/chemistry
- ATP Binding Cassette Transporter, Subfamily G, Member 1/deficiency
- ATP Binding Cassette Transporter, Subfamily G, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily G, Member 1/metabolism
- Amino Acid Sequence
- Animals
- Biological Transport
- CHO Cells
- COS Cells
- Chlorocebus aethiops
- Cholesterol/metabolism
- Cholesterol, HDL/metabolism
- Cricetulus
- Endosomes/metabolism
- Genotype
- HEK293 Cells
- Humans
- Leucine
- Liver X Receptors/agonists
- Liver X Receptors/metabolism
- Macrophages, Peritoneal/drug effects
- Macrophages, Peritoneal/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phenotype
- Primary Cell Culture
- Proline
- Sterol Regulatory Element Binding Protein 2/metabolism
- Transfection
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Affiliation(s)
- Elizabeth J Tarling
- From the Departments of Biological Chemistry (P.A.E.) and Medicine (E.J.T.), David Geffen School of Medicine at the University of California, Los Angeles.
| | - Peter A Edwards
- From the Departments of Biological Chemistry (P.A.E.) and Medicine (E.J.T.), David Geffen School of Medicine at the University of California, Los Angeles
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Coisne C, Hallier-Vanuxeem D, Boucau MC, Hachani J, Tilloy S, Bricout H, Monflier E, Wils D, Serpelloni M, Parissaux X, Fenart L, Gosselet F. β-Cyclodextrins Decrease Cholesterol Release and ABC-Associated Transporter Expression in Smooth Muscle Cells and Aortic Endothelial Cells. Front Physiol 2016; 7:185. [PMID: 27252658 PMCID: PMC4879322 DOI: 10.3389/fphys.2016.00185] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 05/09/2016] [Indexed: 12/14/2022] Open
Abstract
Atherosclerosis is an inflammatory disease that leads to an aberrant accumulation of cholesterol in vessel walls forming atherosclerotic plaques. During this process, the mechanism regulating complex cellular cholesterol pools defined as the reverse cholesterol transport (RCT) is altered as well as expression and functionality of transporters involved in this process, namely ABCA1, ABCG1, and SR-BI. Macrophages, arterial endothelial and smooth muscle cells (SMCs) have been involved in the atherosclerotic plaque formation. As macrophages are widely described as the major cell type forming the foam cells by accumulating intracellular cholesterol, RCT alterations have been poorly studied at the arterial endothelial cell and SMC levels. Amongst the therapeutics tested to actively counteract cellular cholesterol accumulation, the methylated β-cyclodextrin, KLEPTOSE® CRYSMEβ, has recently shown promising effects on decreasing the atherosclerotic plaque size in atherosclerotic mouse models. Therefore we investigated in vitro the RCT process occurring in SMCs and in arterial endothelial cells (ABAE) as well as the ability of some modified β-CDs with different methylation degree to modify RCT in these cells. To this aim, cells were incubated in the presence of different methylated β-CDs, including KLEPTOSE® CRYSMEβ. Both cell types were shown to express basal levels of ABCA1 and SR-BI whereas ABCG1 was solely found in ABAE. Upon CD treatments, the percentage of membrane-extracted cholesterol correlated to the methylation degree of the CDs independently of the lipid composition of the cell membranes. Decreasing the cellular cholesterol content with CDs led to reduce the expression levels of ABCA1 and ABCG1. In addition, the cholesterol efflux to ApoA-I and HDL particles was significantly decreased suggesting that cells forming the blood vessel wall are able to counteract the CD-induced loss of cholesterol. Taken together, our observations suggest that methylated β-CDs can significantly reduce the cellular cholesterol content of cells forming atherosclerotic lesions and can subsequently modulate the expression of ABC transporters involved in RCT. The use of methylated β-CDs would represent a valuable and efficient tool to interfere with atherosclerosis pathogenesis in patients, nonetheless their mode of action still needs further investigations to be fully understood and finely controlled at the cellular level.
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Affiliation(s)
- Caroline Coisne
- EA 2465, Laboratoire de la Barrière Hémato-Encéphalique, Université d'Artois Lens, France
| | | | - Marie-Christine Boucau
- EA 2465, Laboratoire de la Barrière Hémato-Encéphalique, Université d'Artois Lens, France
| | - Johan Hachani
- EA 2465, Laboratoire de la Barrière Hémato-Encéphalique, Université d'Artois Lens, France
| | - Sébastien Tilloy
- Université Artois, CNRS, Centrale Lille, ENSCL, Université Lille, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS) Lens, France
| | - Hervé Bricout
- Université Artois, CNRS, Centrale Lille, ENSCL, Université Lille, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS) Lens, France
| | - Eric Monflier
- Université Artois, CNRS, Centrale Lille, ENSCL, Université Lille, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS) Lens, France
| | - Daniel Wils
- ROQUETTE, Nutrition Direction Lestrem, France
| | | | | | - Laurence Fenart
- EA 2465, Laboratoire de la Barrière Hémato-Encéphalique, Université d'Artois Lens, France
| | - Fabien Gosselet
- EA 2465, Laboratoire de la Barrière Hémato-Encéphalique, Université d'Artois Lens, France
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103
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Westerterp M, Tsuchiya K, Tattersall IW, Fotakis P, Bochem AE, Molusky MM, Ntonga V, Abramowicz S, Parks JS, Welch CL, Kitajewski J, Accili D, Tall AR. Deficiency of ATP-Binding Cassette Transporters A1 and G1 in Endothelial Cells Accelerates Atherosclerosis in Mice. Arterioscler Thromb Vasc Biol 2016; 36:1328-37. [PMID: 27199450 DOI: 10.1161/atvbaha.115.306670] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 05/10/2016] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Plasma high-density lipoproteins have several putative antiatherogenic effects, including preservation of endothelial functions. This is thought to be mediated, in part, by the ability of high-density lipoproteins to promote cholesterol efflux from endothelial cells (ECs). The ATP-binding cassette transporters A1 and G1 (ABCA1 and ABCG1) interact with high-density lipoproteins to promote cholesterol efflux from ECs. To determine the impact of endothelial cholesterol efflux pathways on atherogenesis, we prepared mice with endothelium-specific knockout of Abca1 and Abcg1. APPROACH AND RESULTS Generation of mice with EC-ABCA1 and ABCG1 deficiency required crossbreeding Abca1(fl/fl)Abcg1(fl/fl)Ldlr(-/-) mice with the Tie2Cre strain, followed by irradiation and transplantation of Abca1(fl/fl)Abcg1(fl/fl) bone marrow to abrogate the effects of macrophage ABCA1 and ABCG1 deficiency induced by Tie2Cre. After 20 to 22 weeks of Western-type diet, both single EC-Abca1 and Abcg1 deficiency increased atherosclerosis in the aortic root and whole aorta. Combined EC-Abca1/g1 deficiency caused a significant further increase in lesion area at both sites. EC-Abca1/g1 deficiency dramatically enhanced macrophage lipid accumulation in the branches of the aorta that are exposed to disturbed blood flow, decreased aortic endothelial NO synthase activity, and increased monocyte infiltration into the atherosclerotic plaque. Abca1/g1 deficiency enhanced lipopolysaccharide-induced inflammatory gene expression in mouse aortic ECs, which was recapitulated by ABCG1 deficiency in human aortic ECs. CONCLUSIONS These studies provide direct evidence that endothelial cholesterol efflux pathways mediated by ABCA1 and ABCG1 are nonredundant and atheroprotective, reflecting preservation of endothelial NO synthase activity and suppression of endothelial inflammation, especially in regions of disturbed arterial blood flow.
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MESH Headings
- ATP Binding Cassette Transporter 1/deficiency
- ATP Binding Cassette Transporter 1/genetics
- ATP Binding Cassette Transporter, Subfamily G, Member 1/deficiency
- ATP Binding Cassette Transporter, Subfamily G, Member 1/genetics
- Animals
- Aorta, Thoracic/metabolism
- Aorta, Thoracic/pathology
- Aorta, Thoracic/physiopathology
- Aortic Diseases/genetics
- Aortic Diseases/metabolism
- Aortic Diseases/pathology
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Atherosclerosis/physiopathology
- Bone Marrow Transplantation
- Cholesterol/metabolism
- Diet, High-Fat
- Disease Models, Animal
- Disease Progression
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Genetic Predisposition to Disease
- Inflammation Mediators/metabolism
- Macrophages/metabolism
- Male
- Mice, Knockout
- Monocytes/metabolism
- Neovascularization, Physiologic
- Nitric Oxide Synthase Type III/metabolism
- Phenotype
- Plaque, Atherosclerotic
- Receptors, LDL/deficiency
- Receptors, LDL/genetics
- Regional Blood Flow
- Retinal Neovascularization/genetics
- Retinal Neovascularization/metabolism
- Time Factors
- Tissue Culture Techniques
- Whole-Body Irradiation
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Affiliation(s)
- Marit Westerterp
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.).
| | - Kyoichiro Tsuchiya
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Ian W Tattersall
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Panagiotis Fotakis
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Andrea E Bochem
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Matthew M Molusky
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Vusisizwe Ntonga
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Sandra Abramowicz
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - John S Parks
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Carrie L Welch
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Jan Kitajewski
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Domenico Accili
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
| | - Alan R Tall
- From the Division of Molecular Medicine, Department of Medicine (M.W., P.F., A.E.B., M.M.M., V.N., S.A., C.L.W., A.R.T.), Naomi Berrie Diabetes Center (K.T., D.A.), and Department of Pathology, Obstetrics, and Gynaecology (I.W.T., J.K.), Columbia University, New York, NY; Section on Molecular Genetics, Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands (M.W.); Department of Diabetes, Endocrinology, and Metabolism, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan (K.T.); and Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC (J.S.P.)
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104
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Lee-Rueckert M, Escola-Gil JC, Kovanen PT. HDL functionality in reverse cholesterol transport--Challenges in translating data emerging from mouse models to human disease. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:566-83. [PMID: 26968096 DOI: 10.1016/j.bbalip.2016.03.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 02/26/2016] [Accepted: 03/04/2016] [Indexed: 12/18/2022]
Abstract
Whereas LDL-derived cholesterol accumulates in atherosclerotic lesions, HDL particles are thought to facilitate removal of cholesterol from the lesions back to the liver thereby promoting its fecal excretion from the body. Because generation of cholesterol-loaded macrophages is inherent to atherogenesis, studies on the mechanisms stimulating the release of cholesterol from these cells and its ultimate excretion into feces are crucial to learn how to prevent lesion development or even induce lesion regression. Modulation of this key anti-atherogenic pathway, known as the macrophage-specific reverse cholesterol transport, has been extensively studied in several mouse models with the ultimate aim of applying the emerging knowledge to humans. The present review provides a detailed comparison and critical analysis of the various steps of reverse cholesterol transport in mouse and man. We attempt to translate this in vivo complex scenario into practical concepts, which could serve as valuable tools when developing novel HDL-targeted therapies.
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105
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Yamanaka N, Marqués G, O'Connor MB. Vesicle-Mediated Steroid Hormone Secretion in Drosophila melanogaster. Cell 2016; 163:907-19. [PMID: 26544939 DOI: 10.1016/j.cell.2015.10.022] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 08/05/2015] [Accepted: 09/15/2015] [Indexed: 01/29/2023]
Abstract
Steroid hormones are a large family of cholesterol derivatives regulating development and physiology in both the animal and plant kingdoms, but little is known concerning mechanisms of their secretion from steroidogenic tissues. Here, we present evidence that in Drosophila, endocrine release of the steroid hormone ecdysone is mediated through a regulated vesicular trafficking mechanism. Inhibition of calcium signaling in the steroidogenic prothoracic gland results in the accumulation of unreleased ecdysone, and the knockdown of calcium-mediated vesicle exocytosis components in the gland caused developmental defects due to deficiency of ecdysone. Accumulation of synaptotagmin-labeled vesicles in the gland is observed when calcium signaling is disrupted, and these vesicles contain an ABC transporter that functions as an ecdysone pump to fill vesicles. We propose that trafficking of steroid hormones out of endocrine cells is not always through a simple diffusion mechanism as presently thought, but instead can involve a regulated vesicle-mediated release process.
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Affiliation(s)
- Naoki Yamanaka
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA; Department of Entomology, Institute for Integrative Genome Biology, Center for Disease Vector Research, University of California, Riverside, Riverside, CA 92521, USA.
| | - Guillermo Marqués
- University Imaging Centers, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael B O'Connor
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA.
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106
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Abstract
KATP channels are integral to the functions of many cells and tissues. The use of electrophysiological methods has allowed for a detailed characterization of KATP channels in terms of their biophysical properties, nucleotide sensitivities, and modification by pharmacological compounds. However, even though they were first described almost 25 years ago (Noma 1983, Trube and Hescheler 1984), the physiological and pathophysiological roles of these channels, and their regulation by complex biological systems, are only now emerging for many tissues. Even in tissues where their roles have been best defined, there are still many unanswered questions. This review aims to summarize the properties, molecular composition, and pharmacology of KATP channels in various cardiovascular components (atria, specialized conduction system, ventricles, smooth muscle, endothelium, and mitochondria). We will summarize the lessons learned from available genetic mouse models and address the known roles of KATP channels in cardiovascular pathologies and how genetic variation in KATP channel genes contribute to human disease.
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Affiliation(s)
- Monique N Foster
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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107
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Baldán Á, de Aguiar Vallim TQ. miRNAs and High-Density Lipoprotein metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:2053-2061. [PMID: 26869447 DOI: 10.1016/j.bbalip.2016.01.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/28/2016] [Accepted: 01/29/2016] [Indexed: 12/16/2022]
Abstract
Altered lipoprotein metabolism plays a key role during atherogenesis. For over 50years, epidemiological data have fueled the proposal that HDL-cholesterol (HDL-c) in circulation is inversely correlated to cardiovascular risk. However, the atheroprotective role of HDL is currently the focus of much debate and remains an active field of research. The emerging picture from research in the past decade suggests that HDL function, rather than HDL-c content, is important in disease. Recent developments demonstrate that miRNAs play an important role in fine-tuning the expression of key genes involved in HDL biogenesis, lipidation, and clearance, as well as in determining the amounts of HDL-c in circulation. Thus, it has been proposed that miRNAs that affect HDL metabolism might be exploited therapeutically in patients. Whether HDL-based therapies, alone or in combination with LDL-based treatments (e.g. statins), provide superior outcomes in patients has been recently questioned by human genetics studies and clinical trials. The switch in focus from "HDL-cholesterol" to "HDL function" opens a new paradigm to understand the physiology and therapeutic potential of HDL, and to find novel modulators of cardiovascular risk. In this review we summarize the current knowledge on the regulation of HDL metabolism and function by miRNAs. This article is part of a Special Issue entitled: MicroRNAs and lipid/energy metabolism and related diseases edited by Carlos Fernández-Hernando and Yajaira Suárez.
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Affiliation(s)
- Ángel Baldán
- Edward A. Doisy Department of Biochemistry & Molecular Biology, Center for Cardiovascular Research, and Liver Center, 1100 S. Grand Blvd., Saint Louis University, Saint Louis, MO 63104, United States.
| | - Thomas Q de Aguiar Vallim
- Department of Medicine, Division of Cardiology, 650 Charles E. Young Drive S, A2-237 CHS, UCLA Los Angeles, Los Angeles, CA 90095, United States.
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108
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Gu HM, Wang F, Alabi A, Deng S, Qin S, Zhang DW. Identification of an Amino Acid Residue Critical for Plasma Membrane Localization of ATP-Binding Cassette Transporter G1—Brief Report. Arterioscler Thromb Vasc Biol 2016; 36:253-5. [DOI: 10.1161/atvbaha.115.306592] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/13/2015] [Indexed: 11/16/2022]
Affiliation(s)
- Hong-mei Gu
- From the Departments of Pediatrics and Biochemistry, Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada (H.-M.G., F.W., A.A., S.D., D.-W.Z.); and Institute of Atherosclerosis in Taishan Medical University, Taian, China (S.Q., D.-W.Z.)
| | - Faqi Wang
- From the Departments of Pediatrics and Biochemistry, Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada (H.-M.G., F.W., A.A., S.D., D.-W.Z.); and Institute of Atherosclerosis in Taishan Medical University, Taian, China (S.Q., D.-W.Z.)
| | - Adekunle Alabi
- From the Departments of Pediatrics and Biochemistry, Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada (H.-M.G., F.W., A.A., S.D., D.-W.Z.); and Institute of Atherosclerosis in Taishan Medical University, Taian, China (S.Q., D.-W.Z.)
| | - Shijun Deng
- From the Departments of Pediatrics and Biochemistry, Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada (H.-M.G., F.W., A.A., S.D., D.-W.Z.); and Institute of Atherosclerosis in Taishan Medical University, Taian, China (S.Q., D.-W.Z.)
| | - Shucun Qin
- From the Departments of Pediatrics and Biochemistry, Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada (H.-M.G., F.W., A.A., S.D., D.-W.Z.); and Institute of Atherosclerosis in Taishan Medical University, Taian, China (S.Q., D.-W.Z.)
| | - Da-wei Zhang
- From the Departments of Pediatrics and Biochemistry, Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada (H.-M.G., F.W., A.A., S.D., D.-W.Z.); and Institute of Atherosclerosis in Taishan Medical University, Taian, China (S.Q., D.-W.Z.)
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109
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El Asmar Z, Terrand J, Jenty M, Host L, Mlih M, Zerr A, Justiniano H, Matz RL, Boudier C, Scholler E, Garnier JM, Bertaccini D, Thiersé D, Schaeffer C, Van Dorsselaer A, Herz J, Bruban V, Boucher P. Convergent Signaling Pathways Controlled by LRP1 (Receptor-related Protein 1) Cytoplasmic and Extracellular Domains Limit Cellular Cholesterol Accumulation. J Biol Chem 2016; 291:5116-27. [PMID: 26792864 DOI: 10.1074/jbc.m116.714485] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Indexed: 11/06/2022] Open
Abstract
The low density lipoprotein receptor-related protein 1 (LRP1) is a ubiquitously expressed cell surface receptor that protects from intracellular cholesterol accumulation. However, the underlying mechanisms are unknown. Here we show that the extracellular (α) chain of LRP1 mediates TGFβ-induced enhancement of Wnt5a, which limits intracellular cholesterol accumulation by inhibiting cholesterol biosynthesis and by promoting cholesterol export. Moreover, we demonstrate that the cytoplasmic (β) chain of LRP1 suffices to limit cholesterol accumulation in LRP1(-/-) cells. Through binding of Erk2 to the second of its carboxyl-terminal NPXY motifs, LRP1 β-chain positively regulates the expression of ATP binding cassette transporter A1 (ABCA1) and of neutral cholesterol ester hydrolase (NCEH1). These results highlight the unexpected functions of LRP1 and the canonical Wnt5a pathway and new therapeutic potential in cholesterol-associated disorders including cardiovascular diseases.
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Affiliation(s)
- Zeina El Asmar
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Jérome Terrand
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Marion Jenty
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Lionel Host
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Mohamed Mlih
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Aurélie Zerr
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Hélène Justiniano
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Rachel L Matz
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Christian Boudier
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Estelle Scholler
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France
| | - Jean-Marie Garnier
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), INSERM 964/CNRS UMR 7104, University of Strasbourg, 67401 Illkirch, France
| | - Diego Bertaccini
- CNRS, UMR 7178, University of Strasbourg, 67087 Strasbourg, France, and
| | - Danièle Thiersé
- CNRS, UMR 7178, University of Strasbourg, 67087 Strasbourg, France, and
| | | | | | - Joachim Herz
- Department of Molecular Genetics and Center for Translational Neurodegeneration Research, UT Southwestern Medical Center, Dallas, Texas 75390
| | - Véronique Bruban
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France,
| | - Philippe Boucher
- From the CNRS, UMR 7213, University of Strasbourg, 67401 Illkirch, France,
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110
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Mutharasan RK, Foit L, Thaxton CS. High-Density Lipoproteins for Therapeutic Delivery Systems. J Mater Chem B 2016; 4:188-197. [PMID: 27069624 PMCID: PMC4825811 DOI: 10.1039/c5tb01332a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
High-density lipoproteins (HDL) are a class of natural nanostructures found in the blood and are composed of lipids, proteins, and nucleic acids (e.g. microRNA). Their size, which appears to be well-suited for both tissue penetration/retention as well as payload delivery, long circulation half-life, avoidance of endosomal sequestration, and potential low toxicity are all excellent properties to model in a drug delivery vehicle. In this review, we consider high-density lipoproteins for therapeutic delivery systems. First we discuss the structure and function of natural HDL, describing in detail its biogenesis and transformation from immature, discoidal forms, to more mature, spherical forms. Next we consider features of HDL making them suitable vehicles for drug delivery. We then describe the use of natural HDL, discoidal HDL analogs, and spherical HDL analogs to deliver various classes of drugs, including small molecules, lipids, and oligonucleotides. We briefly consider the notion that the drug delivery vehicles themselves are therapeutic, constituting entities that exhibit "theralivery." Finally, we discuss challenges and future directions in the field.
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Affiliation(s)
- R. Kannan Mutharasan
- Feinberg Cardiovascular Research Institute, 303 E. Chicago Ave., Tarry 14-725, Chicago, IL 60611 United States
| | - Linda Foit
- Feinberg School of Medicine, Department of Urology, Northwestern University, Tarry 16-703, 303 E. Chicago Ave, Chicago, IL 60611, USA
| | - C. Shad Thaxton
- Feinberg School of Medicine, Department of Urology, Northwestern University, Tarry 16-703, 303 E. Chicago Ave, Chicago, IL 60611, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 E. Superior St, Chicago, IL 60611, USA
- International Institute for Nanotechnology (IIN), 2145 Sheridan Road, Evanston, IL 60208, USA
- Robert H Lurie Comprehensive Cancer Center (RHLCCC), Northwestern University, Feinberg School of Medicine, 303 E Superior, Chicago, IL 60611, USA
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111
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Mostafa AM, Hamdy NM, El-Mesallamy HO, Abdel-Rahman SZ. Glucagon-like peptide 1 (GLP-1)-based therapy upregulates LXR-ABCA1/ABCG1 cascade in adipocytes. Biochem Biophys Res Commun 2015; 468:900-5. [PMID: 26603933 DOI: 10.1016/j.bbrc.2015.11.054] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 11/11/2015] [Indexed: 01/31/2023]
Abstract
A promising treatment for obesity involves the use of therapeutic agents that increase the level of the glucagon-like peptide (GLP-1) which reduces appetite and food intake. Native GLP-1 is rapidly metabolized by the dipeptidyl peptidase-4 (DPP-4) enzyme and, as such, GLP-1 mimetics or DPP-4 inhibitors represent promising treatment approaches. Interestingly, obese patient receiving such medications showed improved lipid profiles and cholesterol homeostasis, however the mechanism(s) involved are not known. Members of the ATP-binding cassette (ABC) transporters, including ABCA1 and ABCG1, play essential roles in reverse cholesterol transport and in high density lipoprotein (HDL) formation. These transporters are under the transcriptional regulation of liver X receptor alpha (LXR-α). We hypothesize that GLP-1 mimetics and/or DPP-4 inhibitors modulate ABCA1/ABCG1 expression in adipocytes through an LXR-α mediated process and thus affecting cholesterol homeostasis. 3T3-L1 adipocytes were treated with the DPP-4 inhibitor vildagliptin (2 nM) or the GLP-1 mimetic exendin-4 (5 nM). Gene and protein expression of ABCA1, ABCG1 and LXR-α were determined and correlated with cholesterol efflux. Expression levels of interleukin-6 (IL-6), leptin and the glucose transporter-4 (GLUT-4) were also determined. Treatment with both medications significantly increased the expression of ABCA1, ABCG1, LXR-α and GLUT-4, decreased IL-6 and leptin, and improved cholesterol efflux from adipocytes (P < 0.05). Our data suggest that GLP-1-based therapy modulate ABCA1/ABCG1 expression in adipocytes potentially through an LXR-α mediated process.
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Affiliation(s)
- Ahmed M Mostafa
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston, TX, USA; Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Nadia M Hamdy
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Hala O El-Mesallamy
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Sherif Z Abdel-Rahman
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston, TX, USA.
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112
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Bloise E, Ortiga-Carvalho TM, Reis FM, Lye SJ, Gibb W, Matthews SG. ATP-binding cassette transporters in reproduction: a new frontier. Hum Reprod Update 2015; 22:164-81. [PMID: 26545808 DOI: 10.1093/humupd/dmv049] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/19/2015] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The transmembrane ATP-binding cassette (ABC) transporters actively efflux an array of clinically relevant compounds across biological barriers, and modulate biodistribution of many physiological and pharmacological factors. To date, over 48 ABC transporters have been identified and shown to be directly and indirectly involved in peri-implantation events and fetal/placental development. They efflux cholesterol, steroid hormones, vitamins, cytokines, chemokines, prostaglandins, diverse xenobiotics and environmental toxins, playing a critical role in regulating drug disposition, immunological responses and lipid trafficking, as well as preventing fetal accumulation of drugs and environmental toxins. METHODS This review examines ABC transporters as important mediators of placental barrier functions and key reproductive processes. Expression, localization and function of all identified ABC transporters were systematically reviewed using PubMed and Google Scholar websites to identify relevant studies examining ABC transporters in reproductive tissues in physiological and pathophysiological states. Only reports written in English were incorporated with no restriction on year of publication. While a major focus has been placed on the human, extensive evidence from animal studies is utilized to describe current understanding of the regulation and function of ABC transporters relevant to human reproduction. RESULTS ABC transporters are modulators of steroidogenesis, fertilization, implantation, nutrient transport and immunological responses, and function as 'gatekeepers' at various barrier sites (i.e. blood-testes barrier and placenta) against potentially harmful xenobiotic factors, including drugs and environmental toxins. These roles appear to be species dependent and change as a function of gestation and development. The best-described ABC transporters in reproductive tissues (primarily in the placenta) are the multidrug transporters p-glycoprotein and breast cancer-related protein, the multidrug resistance proteins 1 through 5 and the cholesterol transporters ABCA1 and ABCG1. CONCLUSIONS The ABC transporters have various roles across multiple reproductive tissues. Knowledge of efflux direction, tissue distribution, substrate specificity and regulation of the ABC transporters in the placenta and other reproductive tissues is rapidly expanding. This will allow better understanding of the disposition of specific substrates within reproductive tissues, and facilitate development of novel treatments for reproductive disorders as well as improved approaches to protecting the developing fetus.
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Affiliation(s)
- E Bloise
- Laboratory of Translational Endocrinology, Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - T M Ortiga-Carvalho
- Laboratory of Translational Endocrinology, Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - F M Reis
- Division of Human Reproduction, Department of Obstetrics and Gynecology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - S J Lye
- Department of Physiology, Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON, Canada M5S 1A8 Department Obstetrics & Gynecology, University of Toronto, Toronto, ON, Canada Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - W Gibb
- Department of Obstetrics & Gynecology, University of Ottawa, Ottawa, ON, Canada Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - S G Matthews
- Department of Physiology, Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON, Canada M5S 1A8 Department Obstetrics & Gynecology, University of Toronto, Toronto, ON, Canada Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
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113
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Wei H, Tarling EJ, McMillen TS, Tang C, LeBoeuf RC. ABCG1 regulates mouse adipose tissue macrophage cholesterol levels and ratio of M1 to M2 cells in obesity and caloric restriction. J Lipid Res 2015; 56:2337-47. [PMID: 26489644 DOI: 10.1194/jlr.m063354] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Indexed: 12/27/2022] Open
Abstract
In addition to triacylglycerols, adipocytes contain a large reserve of unesterified cholesterol. During adipocyte lipolysis and cell death seen during severe obesity and weight loss, free fatty acids and cholesterol become available for uptake and processing by adipose tissue macrophages (ATMs). We hypothesize that ATMs become cholesterol enriched and participate in cholesterol clearance from adipose tissue. We previously showed that ABCG1 is robustly upregulated in ATMs taken from obese mice and further enhanced by caloric restriction. Here, we found that ATMs taken from obese and calorie-restricted mice derived from transplantation of WT or Abcg1-deficient bone marrow are cholesterol enriched. ABCG1 levels regulate the ratio of classically activated (M1) to alternatively activated (M2) ATMs and their cellular cholesterol content. Using WT and Abcg1(-/-) cultured macrophages, we found that Abcg1 is most highly expressed by M2 macrophages and that ABCG1 deficiency is sufficient to retard macrophage chemotaxis. However, changes in myeloid expression of Abcg1 did not protect mice from obesity or impaired glucose homeostasis. Overall, ABCG1 modulates ATM cholesterol content in obesity and weight loss regimes leading to an alteration in M1 to M2 ratio that we suggest is due to the extent of macrophage egress from adipose tissue.
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Affiliation(s)
- Hao Wei
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA 98109-8050 Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109-8050
| | - Elizabeth J Tarling
- Department of Medicine David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095-1737 Department of Biological Chemistry, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095-1737
| | - Timothy S McMillen
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA 98109-8050 Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109-8050
| | - Chongren Tang
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA 98109-8050 Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109-8050
| | - Renée C LeBoeuf
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA 98109-8050 Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109-8050
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114
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Huang LH, Elvington A, Randolph GJ. The role of the lymphatic system in cholesterol transport. Front Pharmacol 2015; 6:182. [PMID: 26388772 PMCID: PMC4557107 DOI: 10.3389/fphar.2015.00182] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/12/2015] [Indexed: 11/13/2022] Open
Abstract
Reverse cholesterol transport (RCT) is the pathway for removal of peripheral tissue cholesterol and involves transport of cholesterol back to liver for excretion, starting from cellular cholesterol efflux facilitated by lipid-free apolipoprotein A1 (ApoA1) or other lipidated high-density lipoprotein (HDL) particles within the interstitial space. Extracellular cholesterol then is picked up and transported through the lymphatic vasculature before entering into bloodstream. There is increasing evidence supporting a role for enhanced macrophage cholesterol efflux and RCT in ameliorating atherosclerosis, and recent data suggest that these processes may serve as better diagnostic biomarkers than plasma HDL levels. Hence, it is important to better understand the processes governing ApoA1 and HDL influx into peripheral tissues from the bloodstream, modification and facilitation of cellular cholesterol removal within the interstitial space, and transport through the lymphatic vasculature. New findings will complement therapeutic strategies for the treatment of atherosclerotic vascular disease.
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Affiliation(s)
- Li-Hao Huang
- Department of Pathology and Immunology, Washington University School of Medicine , St. Louis, MO, USA
| | - Andrew Elvington
- Department of Pathology and Immunology, Washington University School of Medicine , St. Louis, MO, USA
| | - Gwendalyn J Randolph
- Department of Pathology and Immunology, Washington University School of Medicine , St. Louis, MO, USA
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115
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Wüstner D, Solanko K. How cholesterol interacts with proteins and lipids during its intracellular transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1908-26. [DOI: 10.1016/j.bbamem.2015.05.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 04/14/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022]
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116
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Lee SD, Tontonoz P. Liver X receptors at the intersection of lipid metabolism and atherogenesis. Atherosclerosis 2015; 242:29-36. [PMID: 26164157 PMCID: PMC4546914 DOI: 10.1016/j.atherosclerosis.2015.06.042] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/19/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Stephen D Lee
- Howard Hughes Medical Institute, Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA 90095, USA
| | - Peter Tontonoz
- Howard Hughes Medical Institute, Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA 90095, USA.
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117
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Aleidi SM, Howe V, Sharpe LJ, Yang A, Rao G, Brown AJ, Gelissen IC. The E3 ubiquitin ligases, HUWE1 and NEDD4-1, are involved in the post-translational regulation of the ABCG1 and ABCG4 lipid transporters. J Biol Chem 2015; 290:24604-13. [PMID: 26296893 DOI: 10.1074/jbc.m115.675579] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Indexed: 11/06/2022] Open
Abstract
The ATP-binding cassette transporter ABCG1 has an essential role in cellular cholesterol homeostasis, and dysregulation has been associated with a number of high burden diseases. Previous studies reported that ABCG1 is ubiquitinated and degraded via the ubiquitin proteasome system. However, so far the molecular mechanism, including the identity of any of the rate-limiting ubiquitination enzymes, or E3 ligases, is unknown. Using liquid chromatography mass spectrometry, we identified two HECT domain E3 ligases associated with ABCG1, named HUWE1 (HECT, UBA, and WWE domain containing 1, E3 ubiquitin protein ligase) and NEDD4-1 (Neural precursor cell-expressed developmentally down regulated gene 4), of which the latter is the founding member of the NEDD4 family of ubiquitin ligases. Silencing both HUWE1 and NEDD4-1 in cells overexpressing human ABCG1 significantly increased levels of the ABCG1 monomeric and dimeric protein forms, however ABCA1 protein expression was unaffected. In addition, ligase silencing increased ABCG1-mediated cholesterol export to HDL in cells overexpressing the transporter as well as in THP-1 macrophages. Reciprocally, overexpression of both ligases resulted in a significant reduction in protein levels of both the ABCG1 monomeric and dimeric forms. Like ABCG1, ABCG4 protein levels and cholesterol export activity were significantly increased after silencing both HUWE1 and NEDD4-1 in cells overexpressing this closely related ABC half-transporter. In summary, we have identified for the first time two E3 ligases that are fundamental enzymes in the post-translational regulation of ABCG1 and ABCG4 protein levels and cellular cholesterol export activity.
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Affiliation(s)
- Shereen M Aleidi
- From the Faculty of Pharmacy, The University of Sydney, Sydney NSW 2006 and
| | - Vicky Howe
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney NSW 2052 Australia
| | - Laura J Sharpe
- From the Faculty of Pharmacy, The University of Sydney, Sydney NSW 2006 and School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney NSW 2052 Australia
| | - Alryel Yang
- From the Faculty of Pharmacy, The University of Sydney, Sydney NSW 2006 and
| | - Geetha Rao
- From the Faculty of Pharmacy, The University of Sydney, Sydney NSW 2006 and
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney NSW 2052 Australia
| | - Ingrid C Gelissen
- From the Faculty of Pharmacy, The University of Sydney, Sydney NSW 2006 and
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118
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Gulati S, Balderes D, Kim C, Guo ZA, Wilcox L, Area-Gomez E, Snider J, Wolinski H, Stagljar I, Granato JT, Ruggles KV, DeGiorgis JA, Kohlwein SD, Schon EA, Sturley SL. ATP-binding cassette transporters and sterol O-acyltransferases interact at membrane microdomains to modulate sterol uptake and esterification. FASEB J 2015. [PMID: 26220175 DOI: 10.1096/fj.14-264796] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A key component of eukaryotic lipid homeostasis is the esterification of sterols with fatty acids by sterol O-acyltransferases (SOATs). The esterification reactions are allosterically activated by their sterol substrates, the majority of which accumulate at the plasma membrane. We demonstrate that in yeast, sterol transport from the plasma membrane to the site of esterification is associated with the physical interaction of the major SOAT, acyl-coenzyme A:cholesterol acyltransferase (ACAT)-related enzyme (Are)2p, with 2 plasma membrane ATP-binding cassette (ABC) transporters: Aus1p and Pdr11p. Are2p, Aus1p, and Pdr11p, unlike the minor acyltransferase, Are1p, colocalize to sterol and sphingolipid-enriched, detergent-resistant microdomains (DRMs). Deletion of either ABC transporter results in Are2p relocalization to detergent-soluble membrane domains and a significant decrease (53-36%) in esterification of exogenous sterol. Similarly, in murine tissues, the SOAT1/Acat1 enzyme and activity localize to DRMs. This subcellular localization is diminished upon deletion of murine ABC transporters, such as Abcg1, which itself is DRM associated. We propose that the close proximity of sterol esterification and transport proteins to each other combined with their residence in lipid-enriched membrane microdomains facilitates rapid, high-capacity sterol transport and esterification, obviating any requirement for soluble intermediary proteins.
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Affiliation(s)
- Sonia Gulati
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Dina Balderes
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Christine Kim
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Zhongmin A Guo
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Lisa Wilcox
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Estela Area-Gomez
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Jamie Snider
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Heimo Wolinski
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Igor Stagljar
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Juliana T Granato
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Kelly V Ruggles
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Joseph A DeGiorgis
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Sepp D Kohlwein
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Eric A Schon
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Stephen L Sturley
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
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Olivier M, BottG R, Frisdal E, Nowick M, Plengpanich W, Desmarchelier C, Roi S, Quinn CM, Gelissen I, Jessup W, Van Eck M, Guérin M, Le Goff W, Reboul E. ABCG1 is involved in vitamin E efflux. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1841:1741-51. [PMID: 25462452 DOI: 10.1016/j.bbalip.2014.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/29/2014] [Accepted: 10/09/2014] [Indexed: 02/07/2023]
Abstract
Vitamin E membrane transport has been shown to involve the cholesterol transporters SR-BI, ABCA1 and NPC1L1. Our aim was to investigate the possible participation of another cholesterol transporter in cellular vitamin E efflux: ABCG1. In Abcgl-deficient mice, vitamin E concentration was reduced in plasma lipoproteins whereas most tissues displayed a higher vitamin E content compared to wild-type mice. α- and γ-tocopherol efflux was increased in CHO cells overexpressing human ABCG1 compared to control cells. Conversely, α- and γ- tocopherol efflux was decreased in ABCG1-knockdown human cells (Hep3B hepatocytes and THP-1 macro- phages). Interestingly, α- and γ-tocopherol significantly downregulated ABCG1 and ABCA1 expression levels in Hep3B and THP-1, an effect confirmed in vivo in rats given vitamin E for 5 days. This was likely due to reduced LXR activation by oxysterols, as Hep3B cells and rat liver treated with vitamin E displayed a significantly reduced content in oxysterols compared to their respective controls. Overall, the present study reveals for the first time that ABCG1 is involved in cellular vitamin E efflux.
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120
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Chen YH, McGowan LD, Cimino PJ, Dahiya S, Leonard JR, Lee DY, Gutmann DH. Mouse low-grade gliomas contain cancer stem cells with unique molecular and functional properties. Cell Rep 2015; 10:1899-912. [PMID: 25772366 DOI: 10.1016/j.celrep.2015.02.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/16/2015] [Accepted: 02/14/2015] [Indexed: 01/19/2023] Open
Abstract
The availability of adult malignant glioma stem cells (GSCs) has provided unprecedented opportunities to identify the mechanisms underlying treatment resistance. Unfortunately, there is a lack of comparable reagents for the study of pediatric low-grade glioma (LGG). Leveraging a neurofibromatosis 1 (Nf1) genetically engineered mouse LGG model, we report the isolation of CD133(+) multi-potent low-grade glioma stem cells (LG-GSCs), which generate glioma-like lesions histologically similar to the parent tumor following injection into immunocompetent hosts. In addition, we demonstrate that these LG-GSCs harbor selective resistance to currently employed conventional and biologically targeted anti-cancer agents, which reflect the acquisition of new targetable signaling pathway abnormalities. Using transcriptomic analysis to identify additional molecular properties, we discovered that mouse and human LG-GSCs harbor high levels of Abcg1 expression critical for protecting against ER-stress-induced mouse LG-GSC apoptosis. Collectively, these findings establish that LGG cancer stem cells have unique molecular and functional properties relevant to brain cancer treatment.
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Affiliation(s)
- Yi-Hsien Chen
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | - Patrick J Cimino
- Department of Pathology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sonika Dahiya
- Department of Pathology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jeffrey R Leonard
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Da Yong Lee
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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121
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Sag D, Cekic C, Wu R, Linden J, Hedrick CC. The cholesterol transporter ABCG1 links cholesterol homeostasis and tumour immunity. Nat Commun 2015; 6:6354. [PMID: 25724068 PMCID: PMC4347884 DOI: 10.1038/ncomms7354] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 01/22/2015] [Indexed: 02/07/2023] Open
Abstract
ATP-binding Cassette Transporter G1 (ABCG1) promotes cholesterol efflux from cells and regulates intracellular cholesterol homeostasis. Here, we demonstrate a role of ABCG1 as a mediator of tumor immunity. Abcg1−/− mice have dramatically suppressed subcutaneous MB49-bladder carcinoma and B16-melanoma growth and prolonged survival. We show that reduced tumor growth in Abcg1−/− mice is myeloid cell-intrinsic and is associated with a phenotypic shift of the macrophages from a tumor-promoting M2 to a tumor-fighting M1 within the tumor. Abcg1−/− macrophages exhibit an intrinsic bias toward M1 polarization with increased NF-κB activation and direct cytotoxicity for tumor cells in vitro. Overall, our study demonstrates that absence of ABCG1 inhibits tumor growth through modulation of macrophage function within the tumor and illustrates a link between cholesterol homeostasis and cancer.
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Affiliation(s)
- Duygu Sag
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Caglar Cekic
- Department of Molecular Biology and Genetics, Bilkent University, Ankara 06800, Turkey
| | - Runpei Wu
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Joel Linden
- Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Catherine C Hedrick
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
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122
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Gál Z, Hegedüs C, Szakács G, Váradi A, Sarkadi B, Özvegy-Laczka C. Mutations of the central tyrosines of putative cholesterol recognition amino acid consensus (CRAC) sequences modify folding, activity, and sterol-sensing of the human ABCG2 multidrug transporter. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:477-87. [DOI: 10.1016/j.bbamem.2014.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/30/2014] [Accepted: 11/06/2014] [Indexed: 02/07/2023]
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123
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Izem L, Greene DJ, Bialkowska K, Morton RE. Overexpression of full-length cholesteryl ester transfer protein in SW872 cells reduces lipid accumulation. J Lipid Res 2015; 56:515-525. [PMID: 25593327 DOI: 10.1194/jlr.m053678] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cells produce two cholesteryl ester transfer protein (CETP) isoforms, full-length and a shorter variant produced by alternative splicing. Blocking synthesis of both isoforms disrupts lipid metabolism and storage. To further define the role of CETP in cellular lipid metabolism, we stably overexpressed full-length CETP in SW872 cells. These CETP(+) cells had several-fold higher intracellular CETP and accumulated 50% less TG due to a 26% decrease in TG synthesis and 2.5-fold higher TG turnover rate. Reduced TG synthesis was due to decreased fatty acid uptake and impaired conversion of diglyceride to TG even though diacylglycerol acyltransferase activity was normal. Sterol-regulatory element binding protein 1 mRNA levels were normal, and although PPARγ expression was reduced, the expression of several of its target genes including adipocyte triglyceride lipase, FASN, and APOE was normal. CETP(+) cells contained smaller lipid droplets, consistent with their higher levels of perilipin protein family (PLIN) 3 compared with PLIN1 and PLIN2. Intracellular CETP was mostly associated with the endoplasmic reticulum, although CETP near lipid droplets poorly colocalized with this membrane. A small pool of CETP resided in the cytoplasm, and a subfraction coisolated with lipid droplets. These data show that overexpression of full-length CETP disrupts lipid homeostasis resulting in the formation of smaller, more metabolically active lipid droplets.
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Affiliation(s)
- Lahoucine Izem
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Diane J Greene
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Katarzyna Bialkowska
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Richard E Morton
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195.
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124
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Pfeiffer L, Wahl S, Pilling LC, Reischl E, Sandling JK, Kunze S, Holdt LM, Kretschmer A, Schramm K, Adamski J, Klopp N, Illig T, Hedman ÅK, Roden M, Hernandez DG, Singleton AB, Thasler WE, Grallert H, Gieger C, Herder C, Teupser D, Meisinger C, Spector TD, Kronenberg F, Prokisch H, Melzer D, Peters A, Deloukas P, Ferrucci L, Waldenberger M. DNA methylation of lipid-related genes affects blood lipid levels. ACTA ACUST UNITED AC 2015; 8:334-42. [PMID: 25583993 DOI: 10.1161/circgenetics.114.000804] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 12/16/2014] [Indexed: 01/03/2023]
Abstract
BACKGROUND Epigenetic mechanisms might be involved in the regulation of interindividual lipid level variability and thus may contribute to the cardiovascular risk profile. The aim of this study was to investigate the association between genome-wide DNA methylation and blood lipid levels high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and total cholesterol. Observed DNA methylation changes were also further analyzed to examine their relationship with previous hospitalized myocardial infarction. METHODS AND RESULTS Genome-wide DNA methylation patterns were determined in whole blood samples of 1776 subjects of the Cooperative Health Research in the Region of Augsburg F4 cohort using the Infinium HumanMethylation450 BeadChip (Illumina). Ten novel lipid-related CpG sites annotated to various genes including ABCG1, MIR33B/SREBF1, and TNIP1 were identified. CpG cg06500161, located in ABCG1, was associated in opposite directions with both high-density lipoprotein cholesterol (β coefficient=-0.049; P=8.26E-17) and triglyceride levels (β=0.070; P=1.21E-27). Eight associations were confirmed by replication in the Cooperative Health Research in the Region of Augsburg F3 study (n=499) and in the Invecchiare in Chianti, Aging in the Chianti Area study (n=472). Associations between triglyceride levels and SREBF1 and ABCG1 were also found in adipose tissue of the Multiple Tissue Human Expression Resource cohort (n=634). Expression analysis revealed an association between ABCG1 methylation and lipid levels that might be partly mediated by ABCG1 expression. DNA methylation of ABCG1 might also play a role in previous hospitalized myocardial infarction (odds ratio, 1.15; 95% confidence interval=1.06-1.25). CONCLUSIONS Epigenetic modifications of the newly identified loci might regulate disturbed blood lipid levels and thus contribute to the development of complex lipid-related diseases.
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125
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Niesor EJ. Will Lipidation of ApoA1 through Interaction with ABCA1 at the Intestinal Level Affect the Protective Functions of HDL? BIOLOGY 2015; 4:17-38. [PMID: 25569858 PMCID: PMC4381214 DOI: 10.3390/biology4010017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/18/2014] [Indexed: 11/16/2022]
Abstract
The relationship between levels of high-density lipoprotein cholesterol (HDL-C) and cardiovascular (CV) risk is well recognized; however, in recent years, large-scale phase III studies with HDL-C-raising or -mimicking agents have failed to demonstrate a clinical benefit on CV outcomes associated with raising HDL-C, casting doubt on the "HDL hypothesis." This article reviews potential reasons for the observed negative findings with these pharmaceutical compounds, focusing on the paucity of translational models and relevant biomarkers related to HDL metabolism that may have confounded understanding of in vivo mechanisms. A unique function of HDL is its ability to interact with the ATP-binding cassette transporter (ABC) A1 via apolipoprotein (Apo) A1. Only recently, studies have shown that this process may be involved in the intestinal uptake of dietary sterols and antioxidants (vitamin E, lutein and zeaxanthin) at the basolateral surface of enterocytes. This parameter should be assessed for HDL-raising drugs in addition to the more documented reverse cholesterol transport (RCT) from peripheral tissues to the liver. Indeed, a single mechanism involving the same interaction between ApoA1 and ABCA1 may encompass two HDL functions previously considered as separate: antioxidant through the intestinal uptake of antioxidants and RCT through cholesterol efflux from loaded cells such as macrophages.
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Affiliation(s)
- Eric J Niesor
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland.
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126
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Zannis VI, Fotakis P, Koukos G, Kardassis D, Ehnholm C, Jauhiainen M, Chroni A. HDL biogenesis, remodeling, and catabolism. Handb Exp Pharmacol 2015; 224:53-111. [PMID: 25522986 DOI: 10.1007/978-3-319-09665-0_2] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this chapter, we review how HDL is generated, remodeled, and catabolized in plasma. We describe key features of the proteins that participate in these processes, emphasizing how mutations in apolipoprotein A-I (apoA-I) and the other proteins affect HDL metabolism. The biogenesis of HDL initially requires functional interaction of apoA-I with the ATP-binding cassette transporter A1 (ABCA1) and subsequently interactions of the lipidated apoA-I forms with lecithin/cholesterol acyltransferase (LCAT). Mutations in these proteins either prevent or impair the formation and possibly the functionality of HDL. Remodeling and catabolism of HDL is the result of interactions of HDL with cell receptors and other membrane and plasma proteins including hepatic lipase (HL), endothelial lipase (EL), phospholipid transfer protein (PLTP), cholesteryl ester transfer protein (CETP), apolipoprotein M (apoM), scavenger receptor class B type I (SR-BI), ATP-binding cassette transporter G1 (ABCG1), the F1 subunit of ATPase (Ecto F1-ATPase), and the cubulin/megalin receptor. Similarly to apoA-I, apolipoprotein E and apolipoprotein A-IV were shown to form discrete HDL particles containing these apolipoproteins which may have important but still unexplored functions. Furthermore, several plasma proteins were found associated with HDL and may modulate its biological functions. The effect of these proteins on the functionality of HDL is the topic of ongoing research.
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Affiliation(s)
- Vassilis I Zannis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118, USA,
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127
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Abstract
High-density lipoprotein (HDL) is considered to be an anti-atherogenic lipoprotein moiety. Generation of genetically modified (total body and tissue-specific knockout) mouse models has significantly contributed to our understanding of HDL function. Here we will review data from knockout mouse studies on the importance of HDL's major alipoprotein apoA-I, the ABC transporters A1 and G1, lecithin:cholesterol acyltransferase, phospholipid transfer protein, and scavenger receptor BI for HDL's metabolism and its protection against atherosclerosis in mice. The initial generation and maturation of HDL particles as well as the selective delivery of its cholesterol to the liver are essential parameters in the life cycle of HDL. Detrimental atherosclerosis effects observed in response to HDL deficiency in mice cannot be solely attributed to the low HDL levels per se, as the low HDL levels are in most models paralleled by changes in non-HDL-cholesterol levels. However, the cholesterol efflux function of HDL is of critical importance to overcome foam cell formation and the development of atherosclerotic lesions in mice. Although HDL is predominantly studied for its atheroprotective action, the mouse data also suggest an essential role for HDL as cholesterol donor for steroidogenic tissues, including the adrenals and ovaries. Furthermore, it appears that a relevant interaction exists between HDL-mediated cellular cholesterol efflux and the susceptibility to inflammation, which (1) provides strong support for the novel concept that inflammation and metabolism are intertwining biological processes and (2) identifies the efflux function of HDL as putative therapeutic target also in other inflammatory diseases than atherosclerosis.
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Affiliation(s)
- Menno Hoekstra
- Division of Biopharmaceutics, Gorlaeus Laboratories, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333CC, Leiden, The Netherlands,
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128
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Neufeld EB, O'Brien K, Walts AD, Stonik JA, Malide D, Combs CA, Remaley AT. The Human ABCG1 Transporter Mobilizes Plasma Membrane and Late Endosomal Non-Sphingomyelin-Associated-Cholesterol for Efflux and Esterification. BIOLOGY 2014; 3:866-91. [PMID: 25485894 PMCID: PMC4280515 DOI: 10.3390/biology3040866] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/22/2014] [Accepted: 11/26/2014] [Indexed: 11/16/2022]
Abstract
We have previously shown that GFP-tagged human ABCG1 on the plasma membrane (PM) and in late endosomes (LE) mobilizes sterol on both sides of the membrane lipid bilayer, thereby increasing cellular cholesterol efflux to lipid surfaces. In the present study, we examined ABCG1-induced changes in membrane cholesterol distribution, organization, and mobility. ABCG1-GFP expression increased the amount of mobile, non-sphingomyelin(SM)-associated cholesterol at the PM and LE, but not the amount of SM-associated-cholesterol or SM. ABCG1-mobilized non-SM-associated-cholesterol rapidly cycled between the PM and LE and effluxed from the PM to extracellular acceptors, or, relocated to intracellular sites of esterification. ABCG1 increased detergent-soluble pools of PM and LE cholesterol, generated detergent-resistant, non-SM-associated PM cholesterol, and increased resistance to both amphotericin B-induced (cholesterol-mediated) and lysenin-induced (SM-mediated) cytolysis, consistent with altered organization of both PM cholesterol and SM. ABCG1 itself resided in detergent-soluble membrane domains. We propose that PM and LE ABCG1 residing at the phase boundary between ordered (Lo) and disordered (Ld) membrane lipid domains alters SM and cholesterol organization thereby increasing cholesterol flux between Lo and Ld, and hence, the amount of cholesterol available for removal by acceptors on either side of the membrane bilayer for either efflux or esterification.
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Affiliation(s)
- Edward B Neufeld
- Lipoprotein Metabolism Section, Cardiovascular and Pulmonary Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Katherine O'Brien
- Lipid Trafficking Core, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Avram D Walts
- Lipid Trafficking Core, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - John A Stonik
- Lipoprotein Metabolism Section, Cardiovascular and Pulmonary Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Daniela Malide
- NHLBI Light Microscopy Core Facility, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Christian A Combs
- NHLBI Light Microscopy Core Facility, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Alan T Remaley
- Lipoprotein Metabolism Section, Cardiovascular and Pulmonary Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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129
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Getz GS, Reardon CA. The mutual interplay of lipid metabolism and the cells of the immune system in relation to atherosclerosis. ACTA ACUST UNITED AC 2014; 9:657-671. [PMID: 25705263 DOI: 10.2217/clp.14.50] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Atherosclerosis is a chronic inflammation in the arterial wall involving cells of the innate and adaptive immune system that is promoted by hyperlipidemia. In addition, the immune system can influence lipids and lipoprotein levels and cellular lipid homeostasis can influence the level and function of the immune cells. We will review the effects of manipulation of adaptive immune cells and immune cell products on lipids and lipoproteins, focusing mainly on studies performed in murine models of atherosclerosis. We also review how lipoproteins and cellular lipid levels, particularly cholesterol levels, influence the function of cells of the innate and adaptive immune systems. The overriding theme is that these interactions are driven by the need to provide the energy and membrane components for cell proliferation and migration, membrane expansion and other functions that are so important in the functioning of the immune cells.
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Affiliation(s)
- Godfrey S Getz
- Department of Pathology, University of Chicago, Box MC 1089, 5841 S. Maryland Avenue, Chicago, IL 60637, USA
| | - Catherine A Reardon
- Department of Pathology, University of Chicago, Box MC 1089, 5841 S. Maryland Avenue, Chicago, IL 60637, USA
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130
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Association between ABCG1 polymorphism rs1893590 and high-density lipoprotein (HDL) in an asymptomatic Brazilian population. Mol Biol Rep 2014; 42:745-54. [PMID: 25398214 DOI: 10.1007/s11033-014-3823-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 11/08/2014] [Indexed: 10/24/2022]
Abstract
ATP binding cassette transporter G1 (ABCG1) promotes lipidation of nascent high-density lipoprotein (HDL) particles, acting as an intracellular transporter. SNP rs1893590 (c.-204A > C) of ABCG1 gene has been previously studied and reported as functional over plasma HDL-C and lipoprotein lipase activity. This study aimed to investigate the relationships of SNP rs1893590 with plasma lipids and lipoproteins in a large Brazilian population. Were selected 654 asymptomatic and normolipidemic volunteers from both genders. Clinical and anthropometrical data were taken and blood samples were drawn after 12 h fasting. Plasma lipids and lipoproteins, as well as HDL particle size and volume were determined. Genomic DNA was isolated for SNP rs1893590 detection by TaqMan(®) OpenArray(®) Real-Time PCR Plataform (Applied Biosystems). Mann-Whitney U, Chi square and two-way ANOVA were the used statistical tests. No significant differences were found in the comparison analyses between the allele groups for all studied parameters. Conversely, significant interactions were observed between SNP and age over plasma HDL-C, were volunteers under 60 years with AA genotype had increased HDL-C (p = 0.048). Similar results were observed in the group with body mass index (BMI) < 25 kg/m(2), where volunteers with AA genotype had higher HDL-C levels (p = 0.0034), plus an increased HDL particle size (p = 0.01). These findings indicate that SNP rs1893590 of ABCG1 has a significant impact over HDL-C under asymptomatic clinical conditions in an age and BMI dependent way.
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131
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Cellular Localization and Trafficking of the Human ABCG1 Transporter. BIOLOGY 2014; 3:781-800. [PMID: 25405320 PMCID: PMC4280511 DOI: 10.3390/biology3040781] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 10/23/2014] [Accepted: 10/28/2014] [Indexed: 11/17/2022]
Abstract
We have developed a suitable heterologous cell expression system to study the localization, trafficking, and site(s) of function of the human ABCG1 transporter. Increased plasma membrane (PM) and late endosomal (LE) cholesterol generated by ABCG1 was removed by lipoproteins and liposomes, but not apoA-I. Delivery of ABCG1 to the PM and LE was required for ABCG1-mediated cellular cholesterol efflux. ABCG1 LEs frequently contacted the PM, providing a collisional mechanism for transfer of ABCG1-mobilized cholesterol, similar to ABCG1-mediated PM cholesterol efflux to lipoproteins. ABCG1-mobilized LE cholesterol also trafficked to the PM by a non-vesicular pathway. Transfer of ABCG1-mobilized cholesterol from the cytoplasmic face of LEs to the PM and concomitant removal of cholesterol from the outer leaflet of the PM bilayer by extracellular acceptors suggests that ABCG1 mobilizes cholesterol on both sides of the lipid bilayer for removal by acceptors. ABCG1 increased uptake of HDL into LEs, consistent with a potential ABCG1-mediated cholesterol efflux pathway involving HDL resecretion. Thus, ABCG1 at the PM mobilizes PM cholesterol and ABCG1 in LE/LYS generates mobile pools of cholesterol that can traffic by both vesicular and non-vesicular pathways to the PM where it can also be transferred to extracellular acceptors with a lipid surface.
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132
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Baldan A, Gonen A, Choung C, Que X, Marquart TJ, Hernandez I, Bjorkhem I, Ford DA, Witztum JL, Tarling EJ. ABCG1 is required for pulmonary B-1 B cell and natural antibody homeostasis. THE JOURNAL OF IMMUNOLOGY 2014; 193:5637-48. [PMID: 25339664 DOI: 10.4049/jimmunol.1400606] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Many metabolic diseases, including atherosclerosis, type 2 diabetes, pulmonary alveolar proteinosis, and obesity, have a chronic inflammatory component involving both innate and adaptive immunity. Mice lacking the ATP-binding cassette transporter G1 (ABCG1) develop chronic inflammation in the lungs, which is associated with the lipid accumulation (cholesterol, cholesterol ester, and phospholipid) and cholesterol crystal deposition that are characteristic of atherosclerotic lesions and pulmonary alveolar proteinosis. In this article, we demonstrate that specific lipids, likely oxidized phospholipids and/or sterols, elicit a lung-specific immune response in Abcg1(-/-) mice. Loss of ABCG1 results in increased levels of specific oxysterols, phosphatidylcholines, and oxidized phospholipids, including 1-palmitoyl-2-(5'-oxovaleroyl)-sn-glycero-3-phosphocholine, in the lungs. Further, we identify a niche-specific increase in natural Ab (NAb)-secreting B-1 B cells in response to this lipid accumulation that is paralleled by increased titers of IgM, IgA, and IgG against oxidation-specific epitopes, such as those on oxidized low-density lipoprotein and malondialdehyde-modified low-density lipoprotein. Finally, we identify a cytokine/chemokine signature that is reflective of increased B cell activation, Ab secretion, and homing. Collectively, these data demonstrate that the accumulation of lipids in Abcg1(-/-) mice induces the specific expansion and localization of B-1 B cells, which secrete NAbs that may help to protect against the development of atherosclerosis. Indeed, despite chronic lipid accumulation and inflammation, hyperlipidemic mice lacking ABCG1 develop smaller atherosclerotic lesions compared with controls. These data also suggest that Abcg1(-/-) mice may represent a new model in which to study the protective functions of B-1 B cells/NAbs and suggest novel targets for pharmacologic intervention and treatment of disease.
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Affiliation(s)
- Angel Baldan
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095; Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University, St. Louis, MO 63104
| | - Ayelet Gonen
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Christina Choung
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095
| | - Xuchu Que
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Tyler J Marquart
- Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University, St. Louis, MO 63104
| | - Irene Hernandez
- Instituto de Investigaciones Biomédicas "Alberto Sols" Consejo Superior de Investigaciones Cientificas - Universidad Autonoma de Madrid, Madrid 28006; Unidad Asociada de Biomedicina IIBM-Universidad de Las Palmas de Gran Canaria, Las Palmas 35016, Spain; and
| | | | - David A Ford
- Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University, St. Louis, MO 63104
| | - Joseph L Witztum
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Elizabeth J Tarling
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095;
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133
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Su L, Mruk DD, Cheng CY. Regulation of drug transporters in the testis by environmental toxicant cadmium, steroids and cytokines. SPERMATOGENESIS 2014; 2:285-293. [PMID: 23248770 PMCID: PMC3521751 DOI: 10.4161/spmg.22536] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The blood-testis barrier (BTB) provides an efficient barrier to restrict paracellular and transcellular transport of substances, such as toxicants and drugs, limiting their entry to the testis to cause injury. This is achieved by the coordinated actions of efflux and influx transporters at the BTB, which are integral membrane proteins that interact with their substrates, such as drugs and toxicants. An efflux transporter (e.g., P-glycoprotein) can either restrict the entry of drugs/toxicants into the testis or actively pump drugs/toxicants out of Sertoli and/or germ cells if they have entered the seminiferous epithelium via influx pumps. This thus provides an effective mechanism to safeguard spermatogenesis. Using Sertoli cells cultured in vitro with an established tight junction (TJ)-permeability barrier which mimicked the BTB in vivo and treated with cadmium chloride (CdCl2), and also in adult rats (~300 g b.w.) treated with CdCl2 (3 mg/kg b.w., via i.p.) to induce testicular injury, cadmium was found to significantly downregulate the expression of efflux (e.g., P-glycoprotein, Mrp1, Abcg1) and influx (e.g., Oatp3, Slc15a1, Scl39a8) transporters. For instance, treatment of Sertoli cells with cadmium induced significant loss of P-glycoprotein and Oatp-3 at the cell-cell interface, which likely facilitated cadmium entry into the Sertoli cell. These findings illustrate that one of the mechanisms by which cadmium enters the testis is mediated by downregulating the expression of drug transporters at the BTB. Furthermore, cytokines and steroids were found to have differential effects in regulating the expression of drug transporters. Summary, the expression of drug transporters in the testis is regulated by toxicants, steroids and cytokines.
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Affiliation(s)
- Linlin Su
- The Mary M. Wohlford Laboratory for Male Contraceptive Research; Center for Biomedical Research; Population Council; New York, NY USA
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134
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Li Y, He PP, Zhang DW, Zheng XL, Cayabyab FS, Yin WD, Tang CK. Lipoprotein lipase: from gene to atherosclerosis. Atherosclerosis 2014; 237:597-608. [PMID: 25463094 DOI: 10.1016/j.atherosclerosis.2014.10.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 10/13/2014] [Accepted: 10/13/2014] [Indexed: 01/21/2023]
Abstract
Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism and responsible for catalyzing lipolysis of triglycerides in lipoproteins. LPL is produced mainly in adipose tissue, skeletal and heart muscle, as well as in macrophage and other tissues. After synthesized, it is secreted and translocated to the vascular lumen. LPL expression and activity are regulated by a variety of factors, such as transcription factors, interactive proteins and nutritional state through complicated mechanisms. LPL with different distributions may exert distinct functions and have diverse roles in human health and disease with close association with atherosclerosis. It may pose a pro-atherogenic or an anti-atherogenic effect depending on its locations. In this review, we will discuss its gene, protein, synthesis, transportation and biological functions, and then focus on its regulation and relationship with atherosclerosis and potential underlying mechanisms. The goal of this review is to provide basic information and novel insight for further studies and therapeutic targets.
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Affiliation(s)
- Yuan Li
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Discovery, Life Science Research Center, University of South China, Hengyang, Hunan 421001, China
| | - Ping-Ping He
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Discovery, Life Science Research Center, University of South China, Hengyang, Hunan 421001, China; School of Nursing, University of South China, Hengyang, Hunan 421001, China
| | - Da-Wei Zhang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Xi-Long Zheng
- Department of Biochemistry and Molecular Biology, The Libin Cardiovascular Institute of Alberta, The Cumming School of Medicine, The University of Calgary, Health Sciences Center, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Fracisco S Cayabyab
- Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Wei-Dong Yin
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Discovery, Life Science Research Center, University of South China, Hengyang, Hunan 421001, China.
| | - Chao-Ke Tang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Discovery, Life Science Research Center, University of South China, Hengyang, Hunan 421001, China.
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135
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Abstract
Most types of cells in the body do not express the capability of catabolizing cholesterol, so cholesterol efflux is essential for homeostasis. For instance, macrophages possess four pathways for exporting free (unesterified) cholesterol to extracellular high density lipoprotein (HDL). The passive processes include simple diffusion via the aqueous phase and facilitated diffusion mediated by scavenger receptor class B, type 1 (SR-BI). Active pathways are mediated by the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1, which are membrane lipid translocases. The efflux of cellular phospholipid and free cholesterol to apolipoprotein A-I promoted by ABCA1 is essential for HDL biogenesis. Current understanding of the molecular mechanisms involved in these four efflux pathways is presented in this minireview.
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Affiliation(s)
- Michael C Phillips
- From the Division of Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-5158
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136
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Canfrán-Duque A, Ramírez CM, Goedeke L, Lin CS, Fernández-Hernando C. microRNAs and HDL life cycle. Cardiovasc Res 2014; 103:414-22. [PMID: 24895349 DOI: 10.1093/cvr/cvu140] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
miRNAs have emerged as important regulators of lipoprotein metabolism. Work over the past few years has demonstrated that miRNAs control the expression of most of the genes associated with high-density lipoprotein (HDL) metabolism, including the ATP transporters, ABCA1 and ABCG1, and the scavenger receptor SRB1. These findings strongly suggest that miRNAs regulate HDL biogenesis, cellular cholesterol efflux, and HDL cholesterol (HDL-C) uptake in the liver, thereby controlling all of the steps of reverse cholesterol transport. Recent work in animal models has demonstrated that manipulating miRNA levels including miR-33 can increase circulating HDL-C. Importantly, antagonizing miR-33 in vivo enhances the regression and reduces the progression of atherosclerosis. These findings support the idea of developing miRNA inhibitors for the treatment of dyslipidaemia and related cardiovascular disorders such as atherosclerosis. This review article focuses on how HDL metabolism is regulated by miRNAs and how antagonizing miRNA expression could be a potential therapy for treating cardiometabolic diseases.
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Affiliation(s)
- Alberto Canfrán-Duque
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, Amistad Research Building, Room 337C, New Haven 06510, CT, USA Integrative Cell Signalling and Neurobiology of Metabolism Program, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Cristina M Ramírez
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, Amistad Research Building, Room 337C, New Haven 06510, CT, USA Integrative Cell Signalling and Neurobiology of Metabolism Program, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Leigh Goedeke
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, Amistad Research Building, Room 337C, New Haven 06510, CT, USA Integrative Cell Signalling and Neurobiology of Metabolism Program, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Chin-Sheng Lin
- Division of Cardiology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Chen-Kung Rd., Neihu 114, Taipei, Taiwan
| | - Carlos Fernández-Hernando
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, Amistad Research Building, Room 337C, New Haven 06510, CT, USA Integrative Cell Signalling and Neurobiology of Metabolism Program, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
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137
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Hong C, Tontonoz P. Liver X receptors in lipid metabolism: opportunities for drug discovery. Nat Rev Drug Discov 2014; 13:433-44. [DOI: 10.1038/nrd4280] [Citation(s) in RCA: 401] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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138
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Engel T, Fobker M, Buchmann J, Kannenberg F, Rust S, Nofer JR, Schürmann A, Seedorf U. 3β,5α,6β-Cholestanetriol and 25-hydroxycholesterol accumulate in ATP-binding cassette transporter G1 (ABCG1)-deficiency. Atherosclerosis 2014; 235:122-9. [PMID: 24833118 DOI: 10.1016/j.atherosclerosis.2014.04.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 04/08/2014] [Accepted: 04/17/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Oxysterols are oxidized derivatives of sterols that have cytotoxic effects and are potent regulators of diverse cellular functions. Efficient oxysterol removal by the sub-family G member 1 of the ATP-binding cassette transporters (ABCG1) is essential for cell survival and control of cellular processes. However, the specific role of ABCG1 in the transport of various oxysterol species has been not systematically investigated to date. Here, we examined the involvement of ABCG1 in the oxysterol metabolism by studying oxysterol tissue levels in a mouse model of Abcg1-deficiency. METHODS AND RESULTS Analysis of lung tissue of Abcg1(-/-) mice on a standard diet revealed that 3β,5α,6β-cholestanetriol (CT) and 25-hydroxycholesterol (HC) accumulated at more than 100-fold higher levels in comparison to wild-type mice. 24S-HC and 27-HC levels were also elevated, but were minor constituents. A radiolabeled assay employing regulable ABCG1-expressing HeLa cell lines revealed that 25-HC export to albumin was dependent on functional ABCG1 expression and could be blocked by an excess of unlabeled 25-HC or 27-HC. In this cell line, 25-HC at low doses triggered mitochondrial membrane potential, and reactive oxygen species production, which are both indirect indicators of cellular energy expenditure. CONCLUSION Our results suggest that 25-HC and CT are physiologic substrates for ABCG1. Excessive accumulation of these oxysterols may explain the increased rate of cell death and the inflammatory phenotype observed in Abcg1-deficient animals and cells.
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Affiliation(s)
- Thomas Engel
- Leibniz-Institute for Arteriosclerosis Research at The Westphalian Wilhelms-University, 48149 Muenster, Germany.
| | - Manfred Fobker
- Center for Laboratory Medicine, University Hospital Muenster, 48149 Muenster, Germany
| | - Jana Buchmann
- German Institute of Human Nutrition, Department of Experimental Diabetology, 14558 Potsdam-Rehbruecke, Germany
| | - Frank Kannenberg
- Center for Laboratory Medicine, University Hospital Muenster, 48149 Muenster, Germany
| | - Stephan Rust
- Leibniz-Institute for Arteriosclerosis Research at The Westphalian Wilhelms-University, 48149 Muenster, Germany
| | - Jerzy-Roch Nofer
- Center for Laboratory Medicine, University Hospital Muenster, 48149 Muenster, Germany
| | - Annette Schürmann
- German Institute of Human Nutrition, Department of Experimental Diabetology, 14558 Potsdam-Rehbruecke, Germany
| | - Udo Seedorf
- Leibniz-Institute for Arteriosclerosis Research at The Westphalian Wilhelms-University, 48149 Muenster, Germany
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139
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Li G, Gu HM, Zhang DW. ATP-binding cassette transporters and cholesterol translocation. IUBMB Life 2014; 65:505-12. [PMID: 23983199 DOI: 10.1002/iub.1165] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/22/2013] [Indexed: 01/26/2023]
Abstract
Cholesterol, a major component of mammalian cell membranes, plays important structural and functional roles. However, accumulation of excessive cholesterol is toxic to cells. Aberrant cholesterol trafficking and accumulation is the molecular basis for many diseases, such as atherosclerotic cardiovascular disease and Tangier's disease. Accumulation of excessive cholesterol is also believed to contribute to the early onset of Alzheimer's disease. Thus, cellular cholesterol homeostasis is tightly regulated by uptake, de novo synthesis, and efflux. Any surplus of cholesterol must either be stored in the cytosol in the form of esters or released from the cell. Recently, several ATP-binding cassette (ABC) transporters, such as ABCA1, ABCG1, ABCG5, and ABCG8 have been shown to play important roles in the regulation of cellular cholesterol homeostasis by mediating cholesterol efflux. Mutations in ABC transporters are associated with several human diseases. In this review, we discuss the physiological roles of ABC transporters and the underlying mechanisms by which they mediate cholesterol translocation.
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Affiliation(s)
- Ge Li
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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140
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Abstract
High-density lipoprotein (HDL) is a complex mixture of lipoproteins that is associated with many minor proteins and lipids that influence the function of HDL. Although HDL is a promising marker and potential therapeutic target based on its epidemiological data and the effects of healthy HDL in vitro in endothelial cells and macrophages, as well as based on infusion studies of reconstituted HDL in patients with hypercholesterolemia, it remains still uncertain whether or not HDL cholesterol–raising drugs will improve outcomes. Recent studies suggest that HDL becomes modified in patients with coronary artery disease or acute coronary syndrome because of oxidative processes that result in alterations in its proteome composition (proteome remodelling) leading to HDL dysfunction.
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Affiliation(s)
- Thomas F. Lüscher
- From Department of Cardiology, University Heart Center (T.F.L., U.L.), and Department of Clinical Chemistry (A.v.E.), University Hospital Zurich, Zurich, Switzerland; Division of Cardiovascular Research, Institute of Physiology, University of Zurich, Zurich, Switzerland (T.F.L., U.L.); and Department of Medicine, University of California, Los Angeles, CA (A.M.F.)
| | - Ulf Landmesser
- From Department of Cardiology, University Heart Center (T.F.L., U.L.), and Department of Clinical Chemistry (A.v.E.), University Hospital Zurich, Zurich, Switzerland; Division of Cardiovascular Research, Institute of Physiology, University of Zurich, Zurich, Switzerland (T.F.L., U.L.); and Department of Medicine, University of California, Los Angeles, CA (A.M.F.)
| | - Arnold von Eckardstein
- From Department of Cardiology, University Heart Center (T.F.L., U.L.), and Department of Clinical Chemistry (A.v.E.), University Hospital Zurich, Zurich, Switzerland; Division of Cardiovascular Research, Institute of Physiology, University of Zurich, Zurich, Switzerland (T.F.L., U.L.); and Department of Medicine, University of California, Los Angeles, CA (A.M.F.)
| | - Alan M. Fogelman
- From Department of Cardiology, University Heart Center (T.F.L., U.L.), and Department of Clinical Chemistry (A.v.E.), University Hospital Zurich, Zurich, Switzerland; Division of Cardiovascular Research, Institute of Physiology, University of Zurich, Zurich, Switzerland (T.F.L., U.L.); and Department of Medicine, University of California, Los Angeles, CA (A.M.F.)
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141
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Westerterp M, Bochem AE, Yvan-Charvet L, Murphy AJ, Wang N, Tall AR. ATP-Binding Cassette Transporters, Atherosclerosis, and Inflammation. Circ Res 2014; 114:157-70. [DOI: 10.1161/circresaha.114.300738] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Marit Westerterp
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Andrea E. Bochem
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Laurent Yvan-Charvet
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Andrew J. Murphy
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Nan Wang
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Alan R. Tall
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
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142
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Srisen K, Röhrl C, Meisslitzer-Ruppitsch C, Ranftler C, Ellinger A, Pavelka M, Neumüller J. Human endothelial progenitor cells internalize high-density lipoprotein. PLoS One 2013; 8:e83189. [PMID: 24386159 PMCID: PMC3875452 DOI: 10.1371/journal.pone.0083189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/10/2013] [Indexed: 12/15/2022] Open
Abstract
Endothelial progenitor cells (EPCs) originate either directly from hematopoietic stem cells or from a subpopulation of monocytes. Controversial views about intracellular lipid traffic prompted us to analyze the uptake of human high density lipoprotein (HDL), and HDL-cholesterol in human monocytic EPCs. Fluorescence and electron microscopy were used to investigate distribution and intracellular trafficking of HDL and its associated cholesterol using fluorescent surrogates (bodipy-cholesterol and bodipy-cholesteryl oleate), cytochemical labels and fluorochromes including horseradish peroxidase and Alexa Fluor® 568. Uptake and intracellular transport of HDL were demonstrated after internalization periods from 0.5 to 4 hours. In case of HDL-Alexa Fluor® 568, bodipy-cholesterol and bodipy-cholesteryl oleate, a photooxidation method was carried out. HDL-specific reaction products were present in invaginations of the plasma membrane at each time of treatment within endocytic vesicles, in multivesicular bodies and at longer periods of uptake, also in lysosomes. Some HDL-positive endosomes were arranged in form of "strings of pearl"- like structures. HDL-positive multivesicular bodies exhibited intensive staining of limiting and vesicular membranes. Multivesicular bodies of HDL-Alexa Fluor® 568-treated EPCs showed multilamellar intra-vacuolar membranes. At all periods of treatment, labeled endocytic vesicles and organelles were apparent close to the cell surface and in perinuclear areas around the Golgi apparatus. No HDL-related particles could be demonstrated close to its cisterns. Electron tomographic reconstructions showed an accumulation of HDL-containing endosomes close to the trans-Golgi-network. HDL-derived bodipy-cholesterol was localized in endosomal vesicles, multivesicular bodies, lysosomes and in many of the stacked Golgi cisternae and the trans-Golgi-network Internalized HDL-derived bodipy-cholesteryl oleate was channeled into the lysosomal intraellular pathway and accumulated prominently in all parts of the Golgi apparatus and in lipid droplets. Subsequently, also the RER and mitochondria were involved. These studies demonstrated the different intracellular pathway of HDL-derived bodipy-cholesterol and HDL-derived bodipy-cholesteryl oleate by EPCs, with concomitant.
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Affiliation(s)
- Kaemisa Srisen
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Clemens Röhrl
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Claudia Meisslitzer-Ruppitsch
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Carmen Ranftler
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Adolf Ellinger
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Margit Pavelka
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
| | - Josef Neumüller
- Center for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, Vienna, Austria
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143
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Wang F, Li G, Gu HM, Zhang DW. Characterization of the role of a highly conserved sequence in ATP binding cassette transporter G (ABCG) family in ABCG1 stability, oligomerization, and trafficking. Biochemistry 2013; 52:9497-509. [PMID: 24320932 PMCID: PMC3880014 DOI: 10.1021/bi401285j] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
ATP-binding cassette transporter
G1 (ABCG1) mediates cholesterol
and oxysterol efflux onto lipidated lipoproteins and plays an important
role in macrophage reverse cholesterol transport. Here, we identified
a highly conserved sequence present in the five ABCG transporter family
members. The conserved sequence is located between the nucleotide
binding domain and the transmembrane domain and contains five amino
acid residues from Asn at position 316 to Phe at position 320 in ABCG1
(NPADF). We found that cells expressing mutant ABCG1, in which Asn316,
Pro317, Asp319, and Phe320 in the conserved sequence were replaced
with Ala simultaneously, showed impaired cholesterol efflux activity
compared with wild type ABCG1-expressing cells. A more detailed mutagenesis
study revealed that mutation of Asn316 or Phe 320 to Ala significantly
reduced cellular cholesterol and 7-ketocholesterol efflux conferred
by ABCG1, whereas replacement of Pro317 or Asp319 with Ala had no
detectable effect. To confirm the important role of Asn316 and Phe320,
we mutated Asn316 to Asp (N316D) and Gln (N316Q), and Phe320 to Ile
(F320I) and Tyr (F320Y). The mutant F320Y showed the same phenotype
as wild type ABCG1. However, the efflux of cholesterol and 7-ketocholesterol
was reduced in cells expressing ABCG1 mutant N316D, N316Q, or F320I
compared with wild type ABCG1. Further, mutations N316Q and F320I
impaired ABCG1 trafficking while having no marked effect on the stability
and oligomerization of ABCG1. The mutant N316Q and F320I could not
be transported to the cell surface efficiently. Instead, the mutant
proteins were mainly localized intracellularly. Thus, these findings
indicate that the two highly conserved amino acid residues, Asn and
Phe, play an important role in ABCG1-dependent export of cellular
cholesterol, mainly through the regulation of ABCG1 trafficking.
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Affiliation(s)
- Faqi Wang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, ‡Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta T6G 2S2, Canada
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Okabe A, Urano Y, Itoh S, Suda N, Kotani R, Nishimura Y, Saito Y, Noguchi N. Adaptive responses induced by 24S-hydroxycholesterol through liver X receptor pathway reduce 7-ketocholesterol-caused neuronal cell death. Redox Biol 2013; 2:28-35. [PMID: 24371802 PMCID: PMC3871289 DOI: 10.1016/j.redox.2013.11.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 02/05/2023] Open
Abstract
Lipid peroxidation products have been known to induce cellular adaptive responses and enhance tolerance against subsequent oxidative stress through up-regulation of antioxidant compounds and enzymes. 24S-hydroxycholesterol (24SOHC) which is endogenously produced oxysterol in the brain plays an important role in maintaining brain cholesterol homeostasis. In this study, we evaluated adaptive responses induced by brain-specific oxysterol 24SOHC in human neuroblastoma SH-SY5Y cells. Cells treated with 24SOHC at sub-lethal concentrations showed significant reduction in cell death induced by subsequent treatment with 7-ketocholesterol (7KC) in both undifferentiated and retinoic acid-differentiated SH-SY5Y cells. These adaptive responses were also induced by other oxysterols such as 25-hydroxycholesterol and 27-hydroxycholesterol which are known to be ligands of liver X receptor (LXR). Co-treatment of 24SOHC with 9-cis retinoic acid, a retinoid X receptor ligand, enhanced the adaptive responses. Knockdown of LXRβ by siRNA diminished the adaptive responses induced by 24SOHC almost completely. The treatment with 24SOHC induced the expression of LXR target genes, such as ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1). The 24SOHC-induced adaptive responses were significantly attenuated by siRNA for ABCG1 but not by siRNA for ABCA1. Taken together, these results strongly suggest that 24SOHC at sub-lethal concentrations induces adaptive responses via transcriptional activation of LXR signaling pathway, thereby protecting neuronal cells from subsequent 7KC-induced cytotoxicity. 24SOHC induces adaptive responses against 7KC-induced cell death in neuronal cells. Co-treatment of 24SOHC with 9cRA, an RXR ligand enhances adaptive responses. Knockdown of LXRβ suppresses 24SOHC-induced adaptive responses. ABCG1 is involved in LXR-mediated adaptive responses by 24SOHC.
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Key Words
- 24S-hydroxycholesterol
- 24SOHC, 24S-hydroxycholesterol
- 7-ketocholesterol
- 7KC, 7-ketocholesterol
- 9cRA, 9-cis retinoic acid
- ABCA1, ATP-binding cassette transporter A1
- ABCG1, ATP-binding cassette transporter G1
- AD, Alzheimer's disease
- ATP-binding cassette transporter G1
- Adaptive responses
- CYP46A1, cholesterol 24-hydroxylase
- Cell death
- FITC, fluorescein isothiocyanate
- HDL, high-density lipoprotein
- LDH, lactate dehydrogenase
- LXR, liver X receptor
- Liver X receptor
- MAP2, microtubule-associated protein 2
- MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
- NC, negative control
- PI, propidium iodide
- RXR, retinoid X receptor
- atRA, all-trans retinoic acid
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Affiliation(s)
| | - Yasuomi Urano
- Corresponding authors. Tel.: +81 774 65 6260; fax: +81 774 65 6262.
| | | | | | | | | | | | - Noriko Noguchi
- Corresponding authors. Tel.: +81 774 65 6260; fax: +81 774 65 6262.
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145
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Freeman SR, Jin X, Anzinger JJ, Xu Q, Purushothaman S, Fessler MB, Addadi L, Kruth HS. ABCG1-mediated generation of extracellular cholesterol microdomains. J Lipid Res 2013; 55:115-27. [PMID: 24212237 DOI: 10.1194/jlr.m044552] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Previous studies have demonstrated that the ATP-binding cassette transporters (ABC)A1 and ABCG1 function in many aspects of cholesterol efflux from macrophages. In this current study, we continued our investigation of extracellular cholesterol microdomains that form during enrichment of macrophages with cholesterol. Human monocyte-derived macrophages and mouse bone marrow-derived macrophages, differentiated with macrophage colony-stimulating factor (M-CSF) or granulocyte macrophage colony-stimulation factor (GM-CSF), were incubated with acetylated LDL (AcLDL) to allow for cholesterol enrichment and processing. We utilized an anti-cholesterol microdomain monoclonal antibody to reveal pools of unesterified cholesterol, which were found both in the extracellular matrix and associated with the cell surface, that we show function in reverse cholesterol transport. Coincubation of AcLDL with 50 μg/ml apoA-I eliminated all extracellular and cell surface-associated cholesterol microdomains, while coincubation with the same concentration of HDL only removed extracellular matrix-associated cholesterol microdomains. Only at an HDL concentration of 200 µg/ml did HDL eliminate the cholesterol microdomains that were cell-surface associated. The deposition of cholesterol microdomains was inhibited by probucol, but it was increased by the liver X receptor (LXR) agonist TO901317, which upregulates ABCA1 and ABCG1. Extracellular cholesterol microdomains did not develop when ABCG1-deficient mouse bone marrow-derived macrophages were enriched with cholesterol. Our findings show that generation of extracellular cholesterol microdomains is mediated by ABCG1 and that reverse cholesterol transport occurs not only at the cell surface but also within the extracellular space.
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Affiliation(s)
- Sebastian R Freeman
- Section of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
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146
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Abstract
At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.
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Affiliation(s)
- Paul N Hopkins
- Cardiovascular Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.
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147
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Record M, Carayon K, Poirot M, Silvente-Poirot S. Exosomes as new vesicular lipid transporters involved in cell-cell communication and various pathophysiologies. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:108-20. [PMID: 24140720 DOI: 10.1016/j.bbalip.2013.10.004] [Citation(s) in RCA: 579] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 09/29/2013] [Accepted: 10/03/2013] [Indexed: 12/14/2022]
Abstract
Exosomes are nanovesicles that have emerged as a new intercellular communication system between an intracellular compartment of a donor cell towards the periphery or an internal compartment of a recipient cell. The bioactivity of exosomes resides not only in their protein and RNA contents but also in their lipidic molecules. Exosomes display original lipids organized in a bilayer membrane and along with the lipid carriers such as fatty acid binding proteins that they contain, exosomes transport bioactive lipids. Exosomes can vectorize lipids such as eicosanoids, fatty acids, and cholesterol, and their lipid composition can be modified by in-vitro manipulation. They also contain lipid related enzymes so that they can constitute an autonomous unit of production of various bioactive lipids. Exosomes can circulate between proximal or distal cells and their fate can be regulated in part by lipidic molecules. Compared to their parental cells, exosomes are enriched in cholesterol and sphingomyelin and their accumulation in cells might modulate recipient cell homeostasis. Exosome release from cells appears to be a general biological process. They have been reported in all biological fluids from which they can be recovered and can be monitors of specific pathophysiological situations. Thus, the lipid content of circulating exosomes could be useful biomarkers of lipid related diseases. Since the first lipid analysis of exosomes ten years ago detailed knowledge of exosomal lipids has accumulated. The role of lipids in exosome fate and bioactivity and how they constitute an additional lipid transport system are considered in this review.
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Affiliation(s)
- Michel Record
- INSERM-UMR 1037, Cancer Research Center of Toulouse (CRCT), Team "Sterol Metabolism and Therapeutic Innovation in Oncology", BP3028, CHU Purpan, Toulouse F-31300, France; Institut Claudius Regaud, 20-24 Rue du Pont Saint-Pierre, 31052 Toulouse Cedex, France; Université Paul Sabatier Toulouse 3, 118 Route de Narbonne, Toulouse, France.
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148
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Röhrl C, Stangl H. HDL endocytosis and resecretion. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1626-33. [PMID: 23939397 PMCID: PMC3795453 DOI: 10.1016/j.bbalip.2013.07.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 07/22/2013] [Accepted: 07/26/2013] [Indexed: 12/23/2022]
Abstract
HDL removes excess cholesterol from peripheral tissues and delivers it to the liver and steroidogenic tissues via selective lipid uptake without catabolism of the HDL particle itself. In addition, endocytosis of HDL holo-particles has been debated for nearly 40years. However, neither the connection between HDL endocytosis and selective lipid uptake, nor the physiological relevance of HDL uptake has been delineated clearly. This review will focus on HDL endocytosis and resecretion and its relation to cholesterol transfer. We will discuss the role of HDL endocytosis in maintaining cholesterol homeostasis in tissues and cell types involved in atherosclerosis, focusing on liver, macrophages and endothelium. We will critically summarize the current knowledge on the receptors mediating HDL endocytosis including SR-BI, F1-ATPase and CD36 and on intracellular HDL transport routes. Dependent on the tissue, HDL is either resecreted (retro-endocytosis) or degraded after endocytosis. Finally, findings on HDL transcytosis across the endothelial barrier will be summarized. We suggest that HDL endocytosis and resecretion is a rather redundant pathway under physiologic conditions. In case of disturbed lipid metabolism, however, HDL retro-endocytosis represents an alternative pathway that enables tissues to maintain cellular cholesterol homeostasis.
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Affiliation(s)
- Clemens Röhrl
- Department of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Herbert Stangl
- Department of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria.
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149
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Tarling EJ, de Aguiar Vallim TQ, Edwards PA. Role of ABC transporters in lipid transport and human disease. Trends Endocrinol Metab 2013; 24:342-50. [PMID: 23415156 PMCID: PMC3659191 DOI: 10.1016/j.tem.2013.01.006] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/16/2013] [Accepted: 01/18/2013] [Indexed: 12/28/2022]
Abstract
Almost half of the 48 human ATP-binding cassette (ABC) transporter proteins are thought to facilitate the ATP-dependent translocation of lipids or lipid-related compounds. Such substrates include cholesterol, plant sterols, bile acids, phospholipids, and sphingolipids. Mutations in a substantial number of the 48 human ABC transporters have been linked to human disease. Indeed the finding that 12 diseases have been associated with abnormal lipid transport and/or homeostasis demonstrates the importance of this family of transporters in cell physiology. This review highlights the role of ABC transporters in lipid transport and movement, in addition to discussing their roles in cellular homeostasis and inherited disorders.
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Affiliation(s)
- Elizabeth J Tarling
- Department of Biological Chemistry, David Geffen School of Medicine at the University of California Los Angeles (UCLA), Los Angeles, CA 90095, USA.
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150
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Daniil G, Zannis VI, Chroni A. Effect of apoA-I Mutations in the Capacity of Reconstituted HDL to Promote ABCG1-Mediated Cholesterol Efflux. PLoS One 2013; 8:e67993. [PMID: 23826352 PMCID: PMC3694867 DOI: 10.1371/journal.pone.0067993] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/23/2013] [Indexed: 12/29/2022] Open
Abstract
ATP binding cassette transporter G1 (ABCG1) mediates the cholesterol transport from cells to high-density lipoprotein (HDL), but the role of apolipoprotein A-I (apoA-I), the main protein constituent of HDL, in this process is not clear. To address this, we measured cholesterol efflux from HEK293 cells or J774 mouse macrophages overexpressing ABCG1 using as acceptors reconstituted HDL (rHDL) containing wild-type or various mutant apoA-I forms. It was found that ABCG1-mediated cholesterol efflux was severely reduced (by 89%) when using rHDL containing the carboxyl-terminal deletion mutant apoA-I[Δ(185–243)]. ABCG1-mediated cholesterol efflux was not affected or moderately decreased by rHDL containing amino-terminal deletion mutants and several mid-region deletion or point apoA-I mutants, and was restored to 69–99% of control by double deletion mutants apoA-I[Δ(1–41)Δ(185–243)] and apoA-I[Δ(1–59)Δ(185–243)]. These findings suggest that the central helices alone of apoA-I associated to rHDL can promote ABCG1-mediated cholesterol efflux. Further analysis showed that rHDL containing the carboxyl-terminal deletion mutant apoA-I[Δ(185–243)] only slightly reduced (by 22%) the ABCG1-mediated efflux of 7-ketocholesterol, indicating that depending on the sterol type, structural changes in rHDL-associated apoA-I affect differently the ABCG1-mediated efflux of cholesterol and 7-ketocholesterol. Overall, our findings demonstrate that rHDL-associated apoA-I structural changes affect the capacity of rHDL to accept cellular cholesterol by an ABCG1-mediated process. The structure-function relationship seen here between rHDL-associated apoA-I mutants and ABCG1-mediated cholesterol efflux closely resembles that seen before in lipid-free apoA-I mutants and ABCA1-dependent cholesterol efflux, suggesting that both processes depend on the same structural determinants of apoA-I.
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Affiliation(s)
- Georgios Daniil
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, Athens, Greece
| | - Vassilis I. Zannis
- Molecular Genetics, Departments of Medicine and Biochemistry, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, Athens, Greece
- * E-mail:
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