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Hoekstra M, de Jong LM, van der Geest R, de Leeuw LR, Krisnamurthi R, Geerling JJ, Van Eck M. LXR Agonist T0901317's Hepatic Impact Overrules Its Atheroprotective Action in Macrophages, Driving Early Atherogenesis in Chow-Diet-Fed Male Apolipoprotein E Knockout Mice. Biomolecules 2024; 14:429. [PMID: 38672446 PMCID: PMC11047872 DOI: 10.3390/biom14040429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/28/2024] Open
Abstract
Preclinical studies regarding the potential of liver X receptor (LXR) agonists to inhibit macrophage foam cell formation and the development of atherosclerotic lesions are generally executed in mice fed with Western-type diets enriched in cholesterol and fat. Here, we investigated whether LXR agonism remains anti-atherogenic under dietary conditions with a low basal hepatic lipogenesis rate. Hereto, atherosclerosis-susceptible male apolipoprotein E knockout mice were fed a low-fat diet with or without 10 mg/kg/day LXR agonist T0901317 supplementation for 8 weeks. Importantly, T0901317 significantly stimulated atherosclerosis susceptibility, despite an associated increase in the macrophage gene expression levels of cholesterol efflux transporters ABCA1 and ABCG1. The pro-atherogenic effect of T0901317 coincided with exacerbated hypercholesterolemia, hypertriglyceridemia, and a significant rise in hepatic triglyceride stores and macrophage numbers. Furthermore, T0901317-treated mice exhibited elevated plasma MCP-1 levels and monocytosis. In conclusion, these findings highlight that the pro-atherogenic hepatic effects of LXR agonism are dominant over the anti-atherogenic effects in macrophages in determining the overall atherosclerosis outcome under low-fat diet feeding conditions. A low-fat diet experimental setting, as compared to the commonly used high-fat-diet-based preclinical setup, thus appears more sensitive in uncovering the potential relevance of the off-target liver effects of novel anti-atherogenic therapeutic approaches that target macrophage LXR.
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Affiliation(s)
- Menno Hoekstra
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands; (L.M.d.J.); (M.V.E.)
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
- Pharmacy Leiden, Leiden, The Netherlands
| | - Laura M. de Jong
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands; (L.M.d.J.); (M.V.E.)
| | - Rick van der Geest
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands; (L.M.d.J.); (M.V.E.)
| | - Lidewij R. de Leeuw
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands; (L.M.d.J.); (M.V.E.)
| | - Rani Krisnamurthi
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands; (L.M.d.J.); (M.V.E.)
| | - Janine J. Geerling
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands; (L.M.d.J.); (M.V.E.)
| | - Miranda Van Eck
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands; (L.M.d.J.); (M.V.E.)
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
- Pharmacy Leiden, Leiden, The Netherlands
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Zeng GG, Lei Q, Jiang WL, Zhang XX, Nie L, Gong X, Zheng K. A new perspective on the current and future development potential of ABCG1. Curr Probl Cardiol 2024; 49:102161. [PMID: 37875209 DOI: 10.1016/j.cpcardiol.2023.102161] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 10/26/2023]
Abstract
ABCG1 is an essential protein involved in the efflux of intracellular cholesterol to the extracellular space, thus playing a critical role in reducing cholesterol accumulation in neighboring tissues. Bibliometric analysis pertains to the interdisciplinary field of quantitative examination of diverse documents using mathematical and statistical techniques. It integrates the investigation of structural and temporal patterns in academic publications with an exploration of subject focus and forms of uncertainty. This research paper examines the historical evolution, current areas of interest, and future development trends of ABCG1 through bibliometric analysis. This study aims to offer readers insights into the research status and emerging trends of ABCG1, thereby assisting researchers in the exciting field to explore novel research avenues. Following rigorous selection, research on ABCG1 has remained highly active over the past two decades. ABCG1 has even started to emerge in previously unrelated fields, such as the field of cancer research. According to the analysis conducted by Citespace, a lot of keywords and influential citations were identified. ABCG1 has been found to establish a connection between cancer and cardiovascular disease, highlighting their interrelationship. This review aims to assist readers who have limited familiarity with ABCG1 research in gaining a rapid understanding of its developmental trajectory. Additionally, it aims to offer researchers potential areas of focus for future studies related to ABCG1.
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Affiliation(s)
- Guang-Gui Zeng
- Affiliated Hengyang Hospital of Hunan Normal University & Hengyang Central Hospital, Hengyang, Hunan 421001, China; Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China; 2020 Grade Excellent Doctor Class of Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China
| | - Qiong Lei
- Hunan Polytechnic of Environment and Biology, Hengyang, Hunan 421001, China
| | - Wan-Li Jiang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China; Departments of Clinical Medicine, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China
| | - Xing-Xing Zhang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China
| | - Liluo Nie
- Affiliated Hengyang Hospital of Hunan Normal University & Hengyang Central Hospital, Hengyang, Hunan 421001, China
| | - Xianghao Gong
- Affiliated Hengyang Hospital of Hunan Normal University & Hengyang Central Hospital, Hengyang, Hunan 421001, China.
| | - Kang Zheng
- Affiliated Hengyang Hospital of Hunan Normal University & Hengyang Central Hospital, Hengyang, Hunan 421001, China.
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Cui HK, Tang CJ, Gao Y, Li ZA, Zhang J, Li YD. An integrative analysis of single-cell and bulk transcriptome and bidirectional mendelian randomization analysis identified C1Q as a novel stimulated risk gene for Atherosclerosis. Front Immunol 2023; 14:1289223. [PMID: 38179058 PMCID: PMC10764496 DOI: 10.3389/fimmu.2023.1289223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Background The role of complement component 1q (C1Q) related genes on human atherosclerotic plaques (HAP) is less known. Our aim is to establish C1Q associated hub genes using single-cell RNA sequencing (scRNA-seq) and bulk RNA analysis to diagnose and predict HAP patients more effectively and investigate the association between C1Q and HAP (ischemic stroke) using bidirectional Mendelian randomization (MR) analysis. Methods HAP scRNA-seq and bulk-RNA data were download from the Gene Expression Omnibus (GEO) database. The C1Q-related hub genes was screened using the GBM, LASSO and XGBoost algorithms. We built machine learning models to diagnose and distinguish between types of atherosclerosis using generalized linear models and receiver operating characteristics (ROC) analyses. Further, we scored the HALLMARK_COMPLEMENT signaling pathway using ssGSEA and confirmed hub gene expression through qRT-PCR in RAW264.7 macrophages and apoE-/- mice. Furthermore, the risk association between C1Q and HAP was assessed through bidirectional MR analysis, with C1Q as exposure and ischemic stroke (IS, large artery atherosclerosis) as outcomes. Inverse variance weighting (IVW) was used as the main method. Results We utilized scRNA-seq dataset (GSE159677) to identify 24 cell clusters and 12 cell types, and revealed seven C1Q associated DEGs in both the scRNA-seq and GEO datasets. We then used GBM, LASSO and XGBoost to select C1QA and C1QC from the seven DEGs. Our findings indicated that both training and validation cohorts had satisfactory diagnostic accuracy for identifying patients with HPAs. Additionally, we confirmed SPI1 as a potential TF responsible for regulating the two hub genes in HAP. Our analysis further revealed that the HALLMARK_COMPLEMENT signaling pathway was correlated and activated with C1QA and C1QC. We confirmed high expression levels of C1QA, C1QC and SPI1 in ox-LDL-treated RAW264.7 macrophages and apoE-/- mice using qPCR. The results of MR indicated that there was a positive association between the genetic risk of C1Q and IS, as evidenced by an odds ratio (OR) of 1.118 (95%CI: 1.013-1.234, P = 0.027). Conclusion The authors have effectively developed and validated a novel diagnostic signature comprising two genes for HAP, while MR analysis has provided evidence supporting a favorable association of C1Q on IS.
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Affiliation(s)
- Hong-Kai Cui
- Department of Neurological Intervention, The First Affiliated Hospital, Xinxiang Medical University, Xinxiang, Henan, China
| | - Chao-Jie Tang
- Institute of Diagnostic and Interventional Radiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yu Gao
- Department of Neurological Intervention, The First Affiliated Hospital, Xinxiang Medical University, Xinxiang, Henan, China
| | - Zi-Ang Li
- Department of Neurological Intervention, The First Affiliated Hospital, Xinxiang Medical University, Xinxiang, Henan, China
| | - Jian Zhang
- Department of Neurological Intervention, The First Affiliated Hospital, Xinxiang Medical University, Xinxiang, Henan, China
| | - Yong-Dong Li
- Department of Neurological Intervention, The First Affiliated Hospital, Xinxiang Medical University, Xinxiang, Henan, China
- Institute of Diagnostic and Interventional Radiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Arias A, Quiroz A, Santander N, Morselli E, Busso D. Implications of High-Density Cholesterol Metabolism for Oocyte Biology and Female Fertility. Front Cell Dev Biol 2022; 10:941539. [PMID: 36187480 PMCID: PMC9518216 DOI: 10.3389/fcell.2022.941539] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/01/2022] [Indexed: 11/28/2022] Open
Abstract
Cholesterol is an essential component of animal cells. Different regulatory mechanisms converge to maintain adequate levels of this lipid because both its deficiency and excess are unfavorable. Low cell cholesterol content promotes its synthesis and uptake from circulating lipoproteins. In contrast, its excess induces the efflux to high-density lipoproteins (HDL) and their transport to the liver for excretion, a process known as reverse cholesterol transport. Different studies suggest that an abnormal HDL metabolism hinders female fertility. HDL are the only lipoproteins detected in substantial amounts in follicular fluid (FF), and their size and composition correlate with embryo quality. Oocytes obtain cholesterol from cumulus cells via gap junctions because they cannot synthesize cholesterol de novo and lack HDL receptors. Recent evidence has supported the possibility that FF HDL play a major role in taking up excess unesterified cholesterol (UC) from the oocyte. Indeed, genetically modified mouse models with disruptions in reverse cholesterol transport, some of which show excessive circulating UC levels, exhibit female infertility. Cholesterol accumulation can affect the egg´s viability, as reported in other cell types, and activate the plasma membrane structure and activity of membrane proteins. Indeed, in mice deficient for the HDL receptor Scavenger Class B Type I (SR-B1), excess circulating HDL cholesterol and UC accumulation in oocytes impairs meiosis arrest and hinders the developmental capacity of the egg. In other cells, the addition of cholesterol activates calcium channels and dysregulates cell death/survival signaling pathways, suggesting that these mechanisms may link altered HDL cholesterol metabolism and infertility. Although cholesterol, and lipids in general, are usually not evaluated in infertile patients, one study reported high circulating UC levels in women showing longer time to pregnancy as an outcome of fertility. Based on the evidence described above, we propose the existence of a well-regulated and largely unexplored system of cholesterol homeostasis controlling traffic between FF HDL and oocytes, with significant implications for female fertility.
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Affiliation(s)
- Andreina Arias
- Laboratory of Nutrition, Metabolism and Reproduction, Research and Innovation Center, Program of Reproductive Biology, Universidad de Los Andes, Santiago, Chile
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alonso Quiroz
- Laboratory of Nutrition, Metabolism and Reproduction, Research and Innovation Center, Program of Reproductive Biology, Universidad de Los Andes, Santiago, Chile
- School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolás Santander
- Instituto de Ciencias de la Salud, Universidad de O’Higgins, Rancagua, Chile
| | - Eugenia Morselli
- Department of Basic Sciences, Faculty of Medicine and Sciences, Universidad San Sebastián, Santiago, Chile
| | - Dolores Busso
- Laboratory of Nutrition, Metabolism and Reproduction, Research and Innovation Center, Program of Reproductive Biology, Universidad de Los Andes, Santiago, Chile
- IMPACT, Center of Interventional Medicine for Precision and Advanced Cellular Therapy, Santiago, Chile
- *Correspondence: Dolores Busso,
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Yang S, Jia J, Liu Y, Li Z, Li Z, Zhang Z, Zhou B, Luan Y, Huang Y, Peng Y, Han T, Xu Y, He Y, Zheng H. Genetic variations in ABCA1/G1 associated with plasma lipid levels and risk of ischemic stroke. Gene 2022; 823:146343. [PMID: 35219812 DOI: 10.1016/j.gene.2022.146343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/08/2022] [Accepted: 02/14/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND ATP binding cassette transporters ABCA1 and ABCG1 play a crucial role in cholesterol efflux and reverse cholesterol transport (RCT), thereby rendering ischemic stroke (IS) susceptibility. Variants of ABCA1/G1 have been implicated in etiology of IS. This study aimed to investigate the association between single-nucleotide polymorphisms (SNPs) of ABCA1/G1 with plasma lipid variability and the risk of IS in Chinese Han Population. METHODS Totally 249 IS patients and 226 healthy controls were enrolled and 10 SNPs of ABCA1/G1 were screened for genotyping by kompetitive allele-specific polymerase chain reaction (KASP) and validated by sanger sequencing. The logistic regression analysis was performed to identify risk alleles of IS and appropriate genetic model. The genetic risk scores (GRS) and predicted risks for all individuals was computed. Based on different plasma lipid levels, we applied stratified analyses for subgroups. Linkage disequilibrium (LD) test was used to explore different functional haplotype combinations. Association between specific allele or genotype of the SNPs of ABCA1/G1 and plasma lipid or lipoproteins levels were also investigated. RESULTS Besides total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), significant differences of clinical data were observed between IS and control group. The rare GG genotype frequencies of rs4149338 on ABCA1 was higher in IS patients than those in controls (11.4%, 4.6%, respectively, P = 0.037). Frequencies of rs57137919 on ABCG1 for rare AA genotype was lower in IS group than those in control group (4.6%, 13.3%, respectively, P = 0.030). GRS showed ability to discriminate IS patients and controls (AUC = 0.633, P < 0.001). Haplotype A-A (rs4149339-rs4149338) was correlated with reduced risk of IS (P = 0.023). Association analysis showed that subjects with rare AA genotype of rs57137919 had the lowest LDL-C levels while rare GG genotype of rs4149338 had lower TC level than those with AA genotype. The mRNA expression of ABCG1 was higher in IS patients, especially in the patients with frequent GG genotype of rs57137919, and was positively correlated with higher ABCG1 expression level and plasma LDL-C level. CONCLUSIONS Polymorphisms of ABCA1/G1 associated with varieties of plasma lipid levels and risk of IS.
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Affiliation(s)
- Shangdong Yang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Jing Jia
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yang Liu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Zheng Li
- Department of Medical Laboratory, Henan Provincial Chest Hospital, Zhengzhou 450008, China
| | - Zhihao Li
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Zhaojing Zhang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Baixue Zhou
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yingying Luan
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yanyang Huang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yue Peng
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Tianyi Han
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yan Xu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Ying He
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China.
| | - Hong Zheng
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China.
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Wu Y, Chen L, Xie Z, Wang C, Zhang J, Yan X. Effects of ABCG1 knockout on proteomic composition of HDL in mice on a chow diet and a High-Fat Diet. Proteomics 2022; 22:e2100028. [PMID: 35234362 DOI: 10.1002/pmic.202100028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/18/2022] [Accepted: 02/18/2022] [Indexed: 11/09/2022]
Abstract
ATP-binding cassette transporter G1 (ABCG1) is a cellular transmembrane protein that transports oxysterol efflux from cells to high-density lipoprotein (HDL) particles in the plasma. Previous studies have demonstrated that an ABCG1 deficiency exerts an antiatherosclerotic function through the effects of oxysterol accumulation in cells to enhance apoptosis and regulate inflammatory processes. However, whether the deficiency of ABCG1 and the corresponding changes in the efflux of oxysterols could take a series of impacts on the proteomic composition of HDL remains unclear. Here, plasma HDL of ABCG1(-/-) mice and their wild-type controls on a normal chow diet (NCD) or a high-fat diet (HFD) were isolated by ultracentrifugation. The proportion of 7-ketocholesterol and the proteomic composition of samples were comparatively analyzed by LC-MS/MS. In NCD-fed mice, lipid metabolism-related protein (arachidonate 12-lipoxygenase) and antioxidative protein (pantetheinase) exhibited increased accumulation, and inflammatory response protein (alpha-1-antitrypsin) was decreased in accumulation in ABCG1(-/-) mice HDL. In HFD-fed mice, fewer proteins were detected than that of NCD-fed mice. The ABCG1(-/-) mice HDL exhibited increased accumulation of lipid metabolism-related proteins (e.g., carboxylesterase 1C, apolipoprotein (apo)C-4) and decreased accumulation of alpha-1-antitrypsin, as well as significantly reduced proportion of 7-ketocholesterol. Additionally, positive correlations were found between 7-ketocholesterol and some essential proteins on HDL, such as alpha-1-antitrypsin, apoA-4, apoB-100 and serum amyloid A. These results suggest a detrimental impact of oxysterols on HDL composition, which might affect the antiatherosclerotic properties of HDL. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Yanxiang Wu
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lianfeng Chen
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ziyan Xie
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chenyu Wang
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiahao Zhang
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaowei Yan
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Ouweneel AB, Reiche ME, Snip OSC, Wever R, van der Wel EJ, Schaftenaar FH, Kauerova S, Lutgens E, Van Eck M, Hoekstra M. Apolipoprotein A1 deficiency in mice primes bone marrow stem cells for T cell lymphopoiesis. J Cell Sci 2022; 135:272619. [PMID: 34698355 PMCID: PMC8645231 DOI: 10.1242/jcs.258901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 10/14/2021] [Indexed: 11/20/2022] Open
Abstract
The bone marrow has emerged as a potentially important target in cardiovascular disease as it generates all leukocytes involved in atherogenesis. In the current study, we evaluated whether a change in bone marrow functionality underlies the increased atherosclerosis susceptibility associated with high-density lipoprotein (HDL) deficiency. We found that HDL deficiency in mice due to the genetic lack of hepatocyte-derived apolipoprotein A1 (APOA1) was associated with an increase in the Lin−Sca-1+Kit+ (LSK) bone marrow stem cell population and lymphoid-primed multipotent progenitor numbers, which translated into a higher production and systemic flux of T cell subsets. In accordance with APOA1 deficiency-associated priming of stem cells to increase T lymphocyte production, atherogenic diet-fed low-density lipoprotein receptor knockout mice transplanted with bone marrow from APOA1-knockout mice displayed marked lymphocytosis as compared to wild-type bone marrow recipients. However, atherosclerotic lesion sizes and collagen contents were similar in the two groups of bone marrow recipients. In conclusion, systemic lack of APOA1 primes bone marrow stem cells for T cell lymphopoiesis. Our data provide novel evidence for a regulatory role of HDL in bone marrow functioning in normolipidemic mice. Summary: Changes in cholesterol metabolism, that is, in high-density lipoprotein levels, can significantly impact leukocyte numbers via modulating bone marrow functionality.
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Affiliation(s)
- Amber B Ouweneel
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333CC Leiden, The Netherlands
| | - Myrthe E Reiche
- Department of Medical Biochemistry, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, University of Amsterdam, 1105AZ Amsterdam, The Netherlands
| | - Olga S C Snip
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333CC Leiden, The Netherlands
| | - Robbert Wever
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333CC Leiden, The Netherlands
| | - Ezra J van der Wel
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333CC Leiden, The Netherlands
| | - Frank H Schaftenaar
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333CC Leiden, The Netherlands
| | - Soňa Kauerova
- Laboratory for Atherosclerosis Research, Institute for Clinical and Experimental Medicine, 12111 Prague, Czech Republic
| | - Esther Lutgens
- Department of Medical Biochemistry, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, University of Amsterdam, 1105AZ Amsterdam, The Netherlands
| | - Miranda Van Eck
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333CC Leiden, The Netherlands
| | - Menno Hoekstra
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333CC Leiden, The Netherlands
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8
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SR-BI deficiency disassociates obesity from hepatic steatosis and glucose intolerance development in high fat diet-fed mice. J Nutr Biochem 2021; 89:108564. [DOI: 10.1016/j.jnutbio.2020.108564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023]
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Mammalian ABCG-transporters, sterols and lipids: To bind perchance to transport? Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1866:158860. [PMID: 33309976 DOI: 10.1016/j.bbalip.2020.158860] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/15/2020] [Accepted: 12/08/2020] [Indexed: 02/08/2023]
Abstract
Members of the ATP binding cassette (ABC) transporter family perform a critical function in maintaining lipid homeostasis in cells as well as the transport of drugs. In this review, we provide an update on the ABCG-transporter subfamily member proteins, which include the homodimers ABCG1, ABCG2 and ABCG4 as well as the heterodimeric complex formed between ABCG5 and ABCG8. This review focusses on progress made in this field of research with respect to their function in health and disease and the recognised transporter substrates. We also provide an update on post-translational regulation, including by transporter substrates, and well as the involvement of microRNA as regulators of transporter expression and activity. In addition, we describe progress made in identifying structural elements that have been recognised as important for transport activity. We furthermore discuss the role of lipids such as cholesterol on the transport function of ABCG2, traditionally thought of as a drug transporter, and provide a model of potential cholesterol binding sites for ABCG2.
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Anastasius M, Luquain-Costaz C, Kockx M, Jessup W, Kritharides L. A critical appraisal of the measurement of serum 'cholesterol efflux capacity' and its use as surrogate marker of risk of cardiovascular disease. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1257-1273. [PMID: 30305243 DOI: 10.1016/j.bbalip.2018.08.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 12/15/2022]
Abstract
The 'cholesterol efflux capacity (CEC)' assay is a simple in vitro measure of the capacities of individual sera to promote the first step of the reverse cholesterol transport pathway, the delivery of cellular cholesterol to plasma HDL. This review describes the cell biology of this model and critically assesses its application as a marker of cardiovascular risk. We describe the pathways for cell cholesterol export, current cell models used in the CEC assay with their limitations and consider the contribution that measurement of serum CEC provides to our understanding of HDL function in vivo.
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Affiliation(s)
- Malcolm Anastasius
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia
| | | | - Maaike Kockx
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia
| | - Wendy Jessup
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia
| | - Leonard Kritharides
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia; Cardiology Department, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia.
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Collier TS, Jin Z, Topbas C, Bystrom C. Rapid Affinity Enrichment of Human Apolipoprotein A-I Associated Lipoproteins for Proteome Analysis. J Proteome Res 2018; 17:1183-1193. [PMID: 29411613 DOI: 10.1021/acs.jproteome.7b00816] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Isolation of high density lipoproteins (HDL) for structural and functional studies typically relies on ultracentrifugation techniques, which are time-consuming and difficult to scale. With emerging interest in the clinical relevance of HDL structure and function to cardiovascular disease, a significant gap exists between current and desirable sample preparation throughput. To enable proteomic studies of HDL with large clinical cohorts, we have developed an affinity enrichment approach that relies on the association of histidine-tagged, lipid free ApoA-I with HDL followed by standard metal chelate chromatography. Characterization of the resulting affinity-enriched ApoA-I associated lipoprotein (AALP) pool using biochemical, electrophoretic, and proteomic analysis demonstrates that the isolated material is closely related in structural features, lipid content, protein complement, and relative protein distribution to HDL isolated by ultracentrifugation using sequential density adjustment. The simplicity of the method provides avenues for high-throughput analysis of HDL associated proteins.
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Affiliation(s)
- Timothy S Collier
- Cleveland HeartLab, Inc. 6701 Carnegie Avenue, Suite 500 Cleveland, Ohio 44103, United States
| | - Zhicheng Jin
- Cleveland HeartLab, Inc. 6701 Carnegie Avenue, Suite 500 Cleveland, Ohio 44103, United States
| | - Celalettin Topbas
- Cleveland HeartLab, Inc. 6701 Carnegie Avenue, Suite 500 Cleveland, Ohio 44103, United States
| | - Cory Bystrom
- Cleveland HeartLab, Inc. 6701 Carnegie Avenue, Suite 500 Cleveland, Ohio 44103, United States
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12
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Critical Role of the Human ATP-Binding Cassette G1 Transporter in Cardiometabolic Diseases. Int J Mol Sci 2017; 18:ijms18091892. [PMID: 28869506 PMCID: PMC5618541 DOI: 10.3390/ijms18091892] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 12/15/2022] Open
Abstract
ATP-binding cassette G1 (ABCG1) is a member of the large family of ABC transporters which are involved in the active transport of many amphiphilic and lipophilic molecules including lipids, drugs or endogenous metabolites. It is now well established that ABCG1 promotes the export of lipids, including cholesterol, phospholipids, sphingomyelin and oxysterols, and plays a key role in the maintenance of tissue lipid homeostasis. Although ABCG1 was initially proposed to mediate cholesterol efflux from macrophages and then to protect against atherosclerosis and cardiovascular diseases (CVD), it becomes now clear that ABCG1 exerts a larger spectrum of actions which are of major importance in cardiometabolic diseases (CMD). Beyond a role in cellular lipid homeostasis, ABCG1 equally participates to glucose and lipid metabolism by controlling the secretion and activity of insulin and lipoprotein lipase. Moreover, there is now a growing body of evidence suggesting that modulation of ABCG1 expression might contribute to the development of diabetes and obesity, which are major risk factors of CVD. In order to provide the current understanding of the action of ABCG1 in CMD, we here reviewed major findings obtained from studies in mice together with data from the genetic and epigenetic analysis of ABCG1 in the context of CMD.
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13
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van der Sluis RJ, Van Eck M, Hoekstra M. Adrenocortical LDL receptor function negatively influences glucocorticoid output. J Endocrinol 2015; 226:145-54. [PMID: 26136384 DOI: 10.1530/joe-15-0023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/01/2015] [Indexed: 12/17/2022]
Abstract
Over 50% of the cholesterol needed by adrenocortical cells for the production of glucocorticoids is derived from lipoproteins. However, the overall contribution of the different lipoproteins and associated uptake pathways to steroidogenesis remains to be determined. Here we aimed to show the importance of LDL receptor (LDLR)-mediated cholesterol acquisition for adrenal steroidogenesis in vivo. Female total body LDLR knockout mice with a human-like lipoprotein profile were bilaterally adrenalectomized and subsequently provided with one adrenal either expressing or genetically lacking the LDLR under their renal capsule to solely modulate adrenocortical LDLR function. Plasma total cholesterol levels and basal plasma corticosterone levels were identical in the two types of adrenal transplanted mice. Strikingly, restoration of adrenal LDLR function significantly reduced the ACTH-mediated stimulation of adrenal steroidogenesis (P<0.001), with plasma corticosterone levels that were respectively 44-59% lower (P<0.01) as compared to adrenal LDLR negative controls. In addition, LDLR positive adrenal transplanted mice exhibited a significant decrease (-39%; P<0.001) in their plasma corticosterone level under fasting stress conditions. Biochemical analysis did not show changes in the expression of genes involved in cholesterol mobilization. However, LDLR expressing adrenal transplants displayed a marked 62% reduction (P<0.05) in the transcript level of the key steroidogenic enzyme HSD3B2. In conclusion, our studies in a mouse model with a human-like lipoprotein profile provide the first in vivo evidence for a novel inhibitory role of the LDLR in the control of adrenal glucocorticoid production.
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Affiliation(s)
- Ronald J van der Sluis
- Division of BiopharmaceuticsCluster BioTherapeutics, Gorlaeus Laboratories, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Miranda Van Eck
- Division of BiopharmaceuticsCluster BioTherapeutics, Gorlaeus Laboratories, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Menno Hoekstra
- Division of BiopharmaceuticsCluster BioTherapeutics, Gorlaeus Laboratories, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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14
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Frisdal E, Le Lay S, Hooton H, Poupel L, Olivier M, Alili R, Plengpanich W, Villard EF, Gilibert S, Lhomme M, Superville A, Miftah-Alkhair L, Chapman MJ, Dallinga-Thie GM, Venteclef N, Poitou C, Tordjman J, Lesnik P, Kontush A, Huby T, Dugail I, Clement K, Guerin M, Le Goff W. Adipocyte ATP-binding cassette G1 promotes triglyceride storage, fat mass growth, and human obesity. Diabetes 2015; 64:840-55. [PMID: 25249572 DOI: 10.2337/db14-0245] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The role of the ATP-binding cassette G1 (ABCG1) transporter in human pathophysiology is still largely unknown. Indeed, beyond its role in mediating free cholesterol efflux to HDL, the ABCG1 transporter equally promotes lipid accumulation in a triglyceride (TG)-rich environment through regulation of the bioavailability of lipoprotein lipase (LPL). Because both ABCG1 and LPL are expressed in adipose tissue, we hypothesized that ABCG1 is implicated in adipocyte TG storage and therefore could be a major actor in adipose tissue fat accumulation. Silencing of Abcg1 expression by RNA interference in 3T3-L1 preadipocytes compromised LPL-dependent TG accumulation during the initial phase of differentiation. Generation of stable Abcg1 knockdown 3T3-L1 adipocytes revealed that Abcg1 deficiency reduces TG storage and diminishes lipid droplet size through inhibition of Pparγ expression. Strikingly, local inhibition of adipocyte Abcg1 in adipose tissue from mice fed a high-fat diet led to a rapid decrease of adiposity and weight gain. Analysis of two frequent ABCG1 single nucleotide polymorphisms (rs1893590 [A/C] and rs1378577 [T/G]) in morbidly obese individuals indicated that elevated ABCG1 expression in adipose tissue was associated with increased PPARγ expression and adiposity concomitant to increased fat mass and BMI (haplotype AT>GC). The critical role of ABCG1 in obesity was further confirmed in independent populations of severe obese and diabetic obese individuals. This study identifies for the first time a major role of adipocyte ABCG1 in adiposity and fat mass growth and suggests that adipose ABCG1 might represent a potential therapeutic target in obesity.
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Affiliation(s)
- Eric Frisdal
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | | | - Henri Hooton
- Université Pierre et Marie Curie-Paris 6, Paris, France INSERM, U872, Nutriomique Team 7, Cordeliers Research Center, Paris, France
| | - Lucie Poupel
- Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Maryline Olivier
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Rohia Alili
- Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France INSERM, U872, Nutriomique Team 7, Cordeliers Research Center, Paris, France
| | - Wanee Plengpanich
- INSERM, UMR_S1166, Team 4, Paris, France King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Patumwan, Bangkok, Thailand
| | - Elise F Villard
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Sophie Gilibert
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Marie Lhomme
- Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Alexandre Superville
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | | | - M John Chapman
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France
| | | | - Nicolas Venteclef
- Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France INSERM, U872, Nutriomique Team 7, Cordeliers Research Center, Paris, France
| | - Christine Poitou
- Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France INSERM, U872, Nutriomique Team 7, Cordeliers Research Center, Paris, France Heart and Metabolism, Assistance-Publique Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris, France
| | - Joan Tordjman
- Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France INSERM, U872, Nutriomique Team 7, Cordeliers Research Center, Paris, France
| | - Philippe Lesnik
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Anatol Kontush
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Thierry Huby
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Isabelle Dugail
- Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France INSERM, U872, Nutriomique Team 7, Cordeliers Research Center, Paris, France
| | - Karine Clement
- Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France INSERM, U872, Nutriomique Team 7, Cordeliers Research Center, Paris, France Heart and Metabolism, Assistance-Publique Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris, France
| | - Maryse Guerin
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Wilfried Le Goff
- INSERM, UMR_S1166, Team 4, Paris, France Université Pierre et Marie Curie-Paris 6, Paris, France Institute of Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
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15
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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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16
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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: 71] [Impact Index Per Article: 7.9] [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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17
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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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18
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Uehara Y, Saku K. High-density lipoprotein and atherosclerosis: Roles of lipid transporters. World J Cardiol 2014; 6:1049-1059. [PMID: 25349649 PMCID: PMC4209431 DOI: 10.4330/wjc.v6.i10.1049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 02/10/2014] [Accepted: 08/31/2014] [Indexed: 02/06/2023] Open
Abstract
Various previous studies have found a negative correlation between the risk of cardiovascular events and serum high-density lipoprotein (HDL) cholesterol levels. The reverse cholesterol transport, a pathway of cholesterol from peripheral tissue to liver which has several potent antiatherogenic properties. For instance, the particles of HDL mediate to transport cholesterol from cells in arterial tissues, particularly from atherosclerotic plaques, to the liver. Both ATP-binding cassette transporters (ABC) A1 and ABCG1 are membrane cholesterol transporters and have been implicated in mediating cholesterol effluxes from cells in the presence of HDL and apolipoprotein A-I, a major protein constituent of HDL. Previous studies demonstrated that ABCA1 and ABCG1 or the interaction between ABCA1 and ABCG1 exerted antiatherosclerotic effects. As a therapeutic approach for increasing HDL cholesterol levels, much focus has been placed on increasing HDL cholesterol levels as well as enhancing HDL biochemical functions. HDL therapies that use injections of reconstituted HDL, apoA-I mimetics, or full-length apoA-I have shown dramatic effectiveness. In particular, a novel apoA-I mimetic peptide, Fukuoka University ApoA-I Mimetic Peptide, effectively removes cholesterol via specific ABCA1 and other transporters, such as ABCG1, and has an antiatherosclerotic effect by enhancing the biological functions of HDL without changing circulating HDL cholesterol levels. Thus, HDL-targeting therapy has significant atheroprotective potential, as it uses lipid transporter-targeting agents, and may prove to be a therapeutic tool for atherosclerotic cardiovascular diseases.
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19
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Abstract
Low plasma levels of HDL-cholesterol (HDL-C) represent a strong and independent risk factor for cardiovascular disease. HDL particles display a wide spectrum of atheroprotective activities, which include effluxing cellular cholesterol, diminishing cellular death, decreasing vascular constriction, reducing inflammatory response, protecting from pathological oxidation, combating bacterial infection, lessening platelet activation, regulating gene expression by virtue of microRNAs, and improving glucose metabolism. It remains presently indeterminate as to whether some biological activities of HDL are more relevant for the protection of the endothelium from atherogenesis when compared with others. The multitude of such activities raises the question of a proper assay to assess HDL functionality ex vivo. Together with clear understanding of molecular mechanisms underlying atheroprotective properties of HDL, such assay will provide a basis to resolve the ultimate question of the HDL field to allow the development of efficient HDL-targeting therapies.
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Affiliation(s)
- Anatol Kontush
- National Institute for Health and Medical Research (INSERM), UMR-ICAN 1166, University of Pierre and Marie Curie - Paris 6, Pitié - Salpétrière University Hospital, ICAN, 75651 Paris Cedex 13, France
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20
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Hsieh V, Kim MJ, Gelissen IC, Brown AJ, Sandoval C, Hallab JC, Kockx M, Traini M, Jessup W, Kritharides L. Cellular cholesterol regulates ubiquitination and degradation of the cholesterol export proteins ABCA1 and ABCG1. J Biol Chem 2014; 289:7524-36. [PMID: 24500716 DOI: 10.1074/jbc.m113.515890] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The objective of this study was to examine the influence of cholesterol in post-translational control of ABCA1 and ABCG1 protein expression. Using CHO cell lines stably expressing human ABCA1 or ABCG1, we observed that the abundance of these proteins is increased by cell cholesterol loading. The response to increased cholesterol is rapid, is independent of transcription, and appears to be specific for these membrane proteins. The effect is mediated through cholesterol-dependent inhibition of transporter protein degradation. Cell cholesterol loading similarly regulates degradation of endogenously expressed ABCA1 and ABCG1 in human THP-1 macrophages. Turnover of ABCA1 and ABCG1 is strongly inhibited by proteasomal inhibitors and is unresponsive to inhibitors of lysosomal proteolysis. Furthermore, cell cholesterol loading inhibits ubiquitination of ABCA1 and ABCG1. Our findings provide evidence for a rapid, cholesterol-dependent, post-translational control of ABCA1 and ABCG1 protein levels, mediated through a specific and sterol-sensitive mechanism for suppression of transporter protein ubiquitination, which in turn decreases proteasomal degradation. This provides a mechanism for acute fine-tuning of cholesterol transporter activity in response to fluctuations in cell cholesterol levels, in addition to the longer term cholesterol-dependent transcriptional regulation of these genes.
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Affiliation(s)
- Victar Hsieh
- From the Atherosclerosis Laboratory, ANZAC Research Institute and
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21
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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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22
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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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23
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Characterization of palmitoylation of ATP binding cassette transporter G1: effect on protein trafficking and function. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1067-78. [PMID: 23388354 DOI: 10.1016/j.bbalip.2013.01.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/14/2013] [Accepted: 01/25/2013] [Indexed: 12/12/2022]
Abstract
ATP-binding cassette transporter G1 (ABCG1) mediates cholesterol efflux onto lipidated apolipoprotein A-I and HDL and plays a role in various important physiological functions. However, the mechanism by which ABCG1 mediates cholesterol translocation is unclear. Protein palmitoylation regulates many functions of proteins such as ABCA1. Here we investigated if ABCG1 is palmitoylated and the subsequent effects on ABCG1-mediated cholesterol efflux. We demonstrated that ABCG1 is palmitoylated in both human embryonic kidney 293 cells and in mouse macrophage, J774. Five cysteine residues located at positions 26, 150, 311, 390 and 402 in the NH2-terminal cytoplasmic region of ABCG1 were palmitoylated. Removal of palmitoylation at Cys311 by mutating the residue to Ala (C311A) or Ser significantly decreased ABCG1-mediated cholesterol efflux. On the other hand, removal of palmitoylation at sites 26, 150, 390 and 402 had no significant effect. We further demonstrated that mutations of Cys311 affected ABCG1 trafficking from the endoplasmic reticulum. Therefore, our data suggest that palmitoylation plays a critical role in ABCG1-mediated cholesterol efflux through the regulation of trafficking.
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Gelissen IC, Sharpe LJ, Sandoval C, Rao G, Kockx M, Kritharides L, Jessup W, Brown AJ. Protein kinase A modulates the activity of a major human isoform of ABCG1. J Lipid Res 2012; 53:2133-2140. [PMID: 22872754 DOI: 10.1194/jlr.m028795] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABCG1 is an ABC half-transporter that exports cholesterol from cells to HDL. This study set out to investigate differences in posttranslational processing of two human ABCG1 protein isoforms, termed ABCG1(+12) and ABCG1(-12), that differ by the presence or absence of a 12 amino acid peptide. ABCG1(+12) is expressed in human cells and tissues, but not in mice. We identified two protein kinase A (PKA) consensus sites in ABCG1(+12), absent from ABCG1(-12). Inhibition of PKA with either of two structurally unrelated inhibitors resulted in a dose-dependent increase in cholesterol export from cells expressing ABCG1(+12), whereas ABCG1(-12)-expressing cells were unaffected. This was associated with stabilization of the ABCG1(+12) protein, and ABCG1(+12)-S389 was necessary to mediate these effects. Mutation of this serine to aspartic acid, simulating a constitutively phosphorylated state, resulted in accelerated degradation of ABCG1(+12) and reduced cholesterol export. Engineering an equivalent PKA site into ABCG1(-12) rendered this isoform responsive to PKA inhibition, confirming the relevance of this sequence. Together, these results demonstrate an additional level of complexity to the posttranslational control of this human ABCG1 isoform that is absent from ABCG1(-12) and the murine ABCG1 homolog.
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Affiliation(s)
| | - Laura J Sharpe
- Faculty of Pharmacy, University of Sydney, Sydney, Australia; School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Cecilia Sandoval
- Centre for Vascular Research, University of New South Wales, Sydney, Australia; Department of Haematology, Prince of Wales Hospital, Sydney, Australia
| | - Geetha Rao
- Faculty of Pharmacy, University of Sydney, Sydney, Australia
| | - Maaike Kockx
- Centre for Vascular Research, University of New South Wales, Sydney, Australia; Department of Haematology, Prince of Wales Hospital, Sydney, Australia
| | - Leonard Kritharides
- Centre for Vascular Research, University of New South Wales, Sydney, Australia; Department of Haematology, Prince of Wales Hospital, Sydney, Australia; Department of Cardiology, Concord Repatriation General Hospital, Sydney, Australia
| | - Wendy Jessup
- Centre for Vascular Research, University of New South Wales, Sydney, Australia; Department of Haematology, Prince of Wales Hospital, Sydney, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
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Olivier M, Tanck MW, Out R, Villard EF, Lammers B, Bouchareychas L, Frisdal E, Superville A, Van Berkel T, Kastelein JJ, Eck MV, Jukema JW, Chapman MJ, Dallinga-Thie GM, Guerin M, Le Goff W. Human ATP-binding cassette G1 controls macrophage lipoprotein lipase bioavailability and promotes foam cell formation. Arterioscler Thromb Vasc Biol 2012; 32:2223-31. [PMID: 22772754 DOI: 10.1161/atvbaha.111.243519] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE The physiological function of the ATP-binding cassette G1 (ABCG1) transporter in humans is not yet elucidated, as no genetic disease caused by ABCG1 mutations has been documented. The goal of our study was, therefore, to investigate the potential role(s) of ABCG1 in lipid metabolism in humans. METHODS AND RESULTS Here we report that among the 104 polymorphisms present in the ABCG1 gene, the analysis of the frequent functional rs1893590 and rs1378577 single nucleotide polymorphisms located in the regulatory region of ABCG1 in the Regression Growth Evaluation Statin Study population revealed that both ABCG1 single nucleotide polymorphisms were significantly associated with plasma lipoprotein lipase (LPL) activity. Moreover, we observed that plasma LPL activity was modestly reduced in Abcg1(-/-) mice as compared with control mice. Adipose tissue and skeletal muscle are the major tissues accounting for levels and activity of plasma LPL in the body. However, beyond its lipolytic action in the plasma compartment, LPL was also described to act locally at the cellular level. Thus, macrophage LPL was reported to promote foam cell formation and atherosclerosis in vivo. Analysis of the relationship between ABCG1 and LPL in macrophages revealed that the knockdown of ABCG1 expression (ABCG1 knockdown) in primary cultures of human monocyte-derived macrophages using small interfering RNAs led to a marked reduction of both the secretion and activity of LPL. Indeed, LPL was trapped at the cell surface of ABCG1 knockdown human monocyte-derived macrophages, likely in cholesterol-rich domains, thereby reducing the bioavailability and activity of LPL. As a consequence, LPL-mediated lipid accumulation in human macrophage foam cells in the presence of triglyceride-rich lipoproteins was abolished when ABCG1 expression was repressed. CONCLUSIONS We presently report that ABCG1 controls LPL activity and promotes lipid accumulation in human macrophages in the presence of triglyceride-rich lipoproteins, thereby suggesting a potential deleterious role of macrophage ABCG1 in metabolic situations associated with high levels of circulating triglyceride-rich lipoproteins together with the presence of macrophages in the arterial wall.
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Kerr ID, Haider AJ, Gelissen IC. The ABCG family of membrane-associated transporters: you don't have to be big to be mighty. Br J Pharmacol 2012; 164:1767-79. [PMID: 21175590 DOI: 10.1111/j.1476-5381.2010.01177.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Along with many other mammalian ATP-binding cassette (ABC) transporters, members of the ABCG group are involved in the regulated transport of hydrophobic compounds across cellular membranes. In humans, five ABCG family members have been identified, encoding proteins ranging from 638 to 678 amino acids in length. All five have been the subject of intensive investigation to better understand their physiological roles, expression patterns, interactions with substrates and inhibitors, and regulation at both the transcript and protein level. The principal substrates for at least four of the ABCG proteins are endogenous and dietary lipids, with ABCG1 implicated in particular in the export of cholesterol, and ABCG5 and G8 forming a functional heterodimer responsible for plant sterol elimination from the body. ABCG2 has a much broader substrate specificity and its ability to transport numerous diverse pharmaceuticals has implications for the absorption, distribution, metabolism, excretion and toxicity (ADMETOx) profile of these compounds. ABCG2 is one of at least three so-called multidrug resistant ABC transporters expressed in humans, and its activity is associated with decreased efficacy of anti-cancer agents in several carcinomas. In addition to its role in cancer, ABCG2 also plays a role in the normal physiological transport of urate and haem, the implications of which are described. We summarize here data on all five human ABCG transporters and provide a current perspective on their roles in human health and disease.
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Affiliation(s)
- Ian D Kerr
- School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham.
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Meurs I, Lammers B, Zhao Y, Out R, Hildebrand RB, Hoekstra M, Van Berkel TJ, Van Eck M. The effect of ABCG1 deficiency on atherosclerotic lesion development in LDL receptor knockout mice depends on the stage of atherogenesis. Atherosclerosis 2012; 221:41-7. [DOI: 10.1016/j.atherosclerosis.2011.11.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 10/25/2011] [Accepted: 11/17/2011] [Indexed: 01/01/2023]
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Ji A, Wroblewski JM, Cai L, de Beer MC, Webb NR, van der Westhuyzen DR. Nascent HDL formation in hepatocytes and role of ABCA1, ABCG1, and SR-BI. J Lipid Res 2011; 53:446-455. [PMID: 22190590 DOI: 10.1194/jlr.m017079] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
To study the mechanisms of hepatic HDL formation, we investigated the roles of ABCA1, ABCG1, and SR-BI in nascent HDL formation in primary hepatocytes isolated from mice deficient in ABCA1, ABCG1, or SR-BI and from wild-type (WT) mice. Under basal conditions, in WT hepatocytes, cholesterol efflux to exogenous apoA-I was accompanied by conversion of apoA-I to HDL-sized particles. LXR activation by T0901317 markedly enhanced the formation of larger HDL-sized particles as well as cellular cholesterol efflux to apoA-I. Glyburide treatment completely abolished the formation of 7.4 nm diameter and greater particles but led to the formation of novel 7.2 nm-sized particles. However, cells lacking ABCA1 failed to form such particles. ABCG1-deficient cells showed similar capacity to efflux cholesterol to apoA-I and to form nascent HDL particles compared with WT cells. Cholesterol efflux to apoA-I and nascent HDL formation were slightly but significantly enhanced in SR-BI-deficient cells compared with WT cells under basal but not LXR activated conditions. As in WT but not in ABCA1-deficient hepatocytes, 7.2 nm-sized particles generated by glyburide treatment were also detected in ABCG1-deficient and SR-BI-deficient hepatocytes. Our data indicate that hepatic nascent HDL formation is highly dependent on ABCA1 but not on ABCG1 or SR-BI.
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Affiliation(s)
- Ailing Ji
- Departments of Internal Medicine, University of Kentucky, Lexington, KY; Cardiovascular Research Center, University of Kentucky, Lexington, KY; Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
| | - Joanne M Wroblewski
- Departments of Internal Medicine, University of Kentucky, Lexington, KY; Cardiovascular Research Center, University of Kentucky, Lexington, KY; Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
| | - Lei Cai
- Departments of Internal Medicine, University of Kentucky, Lexington, KY; Cardiovascular Research Center, University of Kentucky, Lexington, KY; Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
| | - Maria C de Beer
- Physiology, University of Kentucky, Lexington, KY; Cardiovascular Research Center, University of Kentucky, Lexington, KY; Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
| | - Nancy R Webb
- Departments of Internal Medicine, University of Kentucky, Lexington, KY; Cardiovascular Research Center, University of Kentucky, Lexington, KY; Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
| | - Deneys R van der Westhuyzen
- Departments of Internal Medicine, University of Kentucky, Lexington, KY; Cardiovascular Research Center, University of Kentucky, Lexington, KY; Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY; Molecular and Cellular Biochemistry and Physiology, University of Kentucky, Lexington, KY; Department of Veterans Affairs Medical Center, Lexington, KY.
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Schou J, Frikke-Schmidt R, Kardassis D, Thymiakou E, Nordestgaard BG, Jensen G, Grande P, Tybjærg-Hansen A. Genetic variation in ABCG1 and risk of myocardial infarction and ischemic heart disease. Arterioscler Thromb Vasc Biol 2011; 32:506-15. [PMID: 22155456 DOI: 10.1161/atvbaha.111.234872] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE ATP binding cassette transporter G1 (ABCG1) facilitates cholesterol efflux from macrophages to mature high-density lipoprotein particles. Whether genetic variation in ABCG1 affects risk of atherosclerosis in humans remains to be determined. METHODS AND RESULTS We resequenced the core promoter and coding regions of ABCG1 in 380 individuals from the general population. Next, we genotyped 10 237 individuals from the Copenhagen City Heart Study for the identified variants and determined the effect on lipid and lipoprotein levels and on risk of myocardial infarction (MI) and ischemic heart disease (IHD). g.-376C>T, g.-311T>A, and Ser630Leu predicted risk of MI in the Copenhagen City Heart Study, with hazard ratios of 2.2 (95% confidence interval: 1.2-4.3), 1.7 (1.0-2.9), and 7.5 (1.9-30), respectively. These results were confirmed for g.-376C>T in a case-control study comprising 4983 independently ascertained IHD cases and 7489 controls. Expression levels of ABCG1 mRNA were decreased by approximately 40% in g.-376C>T heterozygotes versus noncarriers (probability values: 0.005-0.009). Finally, in vitro specificity protein 1 (Sp1) bound specifically to a putative Sp1 binding site at position -382 to -373 in the ABCG1 promoter, and the presence of the -376 T allele reduced binding and transactivation of the promoter by Sp1. CONCLUSIONS This is the first report of a functional variant in ABCG1 that associates with increased risk of MI and IHD in the general population.
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Affiliation(s)
- Jesper Schou
- Department of Clinical Biochemistry KB3011, Section for Molecular Genetics, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
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Identification of an amino acid residue in ATP-binding cassette transport G1 critical for mediating cholesterol efflux. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:552-9. [PMID: 21821149 DOI: 10.1016/j.bbalip.2011.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 07/07/2011] [Accepted: 07/15/2011] [Indexed: 01/31/2023]
Abstract
The ATP-binding cassette transporter G1 (ABCG1) mediates free cholesterol efflux onto lipidated apolipoprotein A-I (apoA-I) and plays an important role in macrophage reverse cholesterol transport thereby reducing atherosclerosis. However, how ABCG1 mediates the efflux of cholesterol onto lipidated apoA-I is unclear. Since the crystal structure of ABCG family is not available, other approaches such as site-directed mutagenesis have been widely used to identify amino acid residues important for protein functions. We noticed that ABCG1 contains a single cysteine residue in its putative transmembrane domains. This cysteine residue locates at position 514 (Cys(514)) within the third putative transmembrane domain and is highly conserved. Replacement of Cys(514) with Ala (C514A) essentially abolished ABCG1-mediated cholesterol efflux onto lipidated apoA-I. Substitution of Cys(514) with more conserved amino acid residues, Ser or Thr, also significantly decreased cholesterol efflux. However, mutation C514A had no detectable effect on protein stability and trafficking. Mutation C514A also did not affect the dimerization of ABCG1. Our findings demonstrated that the sulfhydryl group of Cys residue located at position 514 plays a critical role in ABCG1-mediated cholesterol efflux. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Lin CY, Lee TS, Chen CC, Chang CA, Lin YJ, Hsu YP, Ho LT. Endothelin-1 exacerbates lipid accumulation by increasing the protein degradation of the ATP-binding cassette transporter G1 in macrophages. J Cell Physiol 2011; 226:2198-205. [PMID: 21520072 DOI: 10.1002/jcp.22556] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Endothelin-1 (ET-1), a potent proatherogenic vasoconstrictive peptide, is known to promote macrophage foam cell formation via mechanisms that are not fully understood. Excessive lipid accumulation in macrophages is a major hallmark during the early stages of atherosclerotic lesions. Cholesterol homeostasis is tightly regulated by scavenger receptors (SRs) and ATP-binding cassette (ABC) transporters during the transformation of macrophage foam cells. The aim of this study was to investigate the possible mechanisms by which ET-1 affects lipid accumulation in macrophages. Our results demonstrate that oxidized low-density lipoprotein (oxLDL) treatment increases lipid accumulation in rat bone marrow-derived macrophages. Combined treatment with ET-1 and oxLDL significantly exacerbated lipid accumulation in macrophages as compared to treatment with oxLDL alone. The results of Western blotting show that ET-1 markedly decreased the ABCG1 levels via ET type A and B receptors and activation of the phosphatidylinositol 3-kinase pathway; however, ET-1 had no effect on the protein expression of CD36, SR-BI, SR-A, or ABCA1. In addition, real-time PCR analysis showed that ET-1 treatment did not affect ABCG1 mRNA expression. We also found that ET-1 decreases ABCG1 possibly due to the enhancement of the proteosome/calpain pathway-dependent degradation of ABCG1. Moreover, ET-1 significantly reduced the efficiency of the cholesterol efflux in macrophages. Taken together, these findings suggest that ET-1 may impair cholesterol efflux and further exacerbate lipid accumulation during the transformation of macrophage foam cells.
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Affiliation(s)
- Chun-Yueh Lin
- Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
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Hori N, Hayashi H, Sugiyama Y. Calpain-mediated cleavage negatively regulates the expression level of ABCG1. Atherosclerosis 2011; 215:383-91. [DOI: 10.1016/j.atherosclerosis.2010.12.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Revised: 12/16/2010] [Accepted: 12/28/2010] [Indexed: 11/29/2022]
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James RW, Brulhart-Meynet MC, Singh AK, Riederer B, Seidler U, Out R, Van Berkel TJ, Deakin S. The Scavenger Receptor Class B, Type I Is a Primary Determinant of Paraoxonase-1 Association With High-Density Lipoproteins. Arterioscler Thromb Vasc Biol 2010; 30:2121-7. [DOI: 10.1161/atvbaha.110.209122] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Objective—
To examine the contribution of the scavenger receptor (SR) BI to the mechanism by which high-density lipoprotein (HDL) acquires paraoxonase-1 (PON1).
Methods and Results—
Serum PON1 activity contributes to the antioxidant capacity of HDLs and is suggested to be an independent risk factor for atherosclerosis. The association of PON1 with HDL is a major determinant of its serum activity levels. PON1 secretion was studied in stably transfected Chinese hamster ovary and HepG2 models. Complementary analyses were performed in transgenic models. Modulation of SR-BI expression, by SR-BI small and interfering RNA knockdown and pharmacologically, correlated with significant changes (
P
<0.01) in PON1 secretion to HDLs and very-low-density lipoproteins. Block lipid transport-1 (BLT1), which increases the affinity of HDL for SR-BI without modulating its expression, was associated with significant increases in secretion. Downregulating postsynaptic density 95/disc-large/zona occludens kinase in HepG2 reduced cell SR-BI protein and lowered enzyme secretion. Serum PON1 activity was significantly reduced in postsynaptic density 95/disc-large/zona occludens kinase knockout mice.
Conclusion—
The present study identifies SR-BI as a major determinant of the capacity of HDL to acquire PON1. It reinforces the concept of the receptor as a docking molecule, allowing communication between HDL and the cell, and extends the importance of SR-BI to HDL metabolism and function.
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Affiliation(s)
- Richard W. James
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Marie-Claude Brulhart-Meynet
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Anurag Kumar Singh
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Brigitte Riederer
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Ursula Seidler
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Ruud Out
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Theo J.C. Van Berkel
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Sara Deakin
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
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Westerterp M, Koetsveld J, Yu S, Han S, Li R, Goldberg IJ, Welch CL, Tall AR. Increased atherosclerosis in mice with vascular ATP-binding cassette transporter G1 deficiency--brief report. Arterioscler Thromb Vasc Biol 2010; 30:2103-5. [PMID: 20705913 DOI: 10.1161/atvbaha.110.212985] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The objective of this study was to investigate the role of vascular ATP-binding cassette transporter G1 (ABCG1) in atherogenesis without a confounding difference in macrophage ABCG1 expression. ABCG1 is highly expressed in macrophages and endothelial cells. ABCG1 preserves endothelial function by maintaining endothelial NO synthase activity and by reducing adhesion molecule expression and monocyte adhesion. METHODS AND RESULTS To investigate the role of vascular ABCG1 in atherosclerosis in vivo Abcg1(-/-)/Ldlr(-/-) and Ldlr(-/-) mice were transplanted with wild-type bone marrow and fed a Western-type diet for 12 or 23 weeks. The atherosclerotic lesion area was similar in both groups after 12 weeks but was increased in Abcg1(-/-)/Ldlr(-/-) recipients after 23 weeks, especially in the aortic arch (2.2-fold; P<0.01). Endothelial NO synthase-mediated vascular relaxation was impaired in male Abcg1(-/-)/Ldlr(-/-) recipients. CONCLUSIONS Our data show an atheroprotective role of vascular ABCG1, especially in the aortic arch, likely related to its role in the preservation of endothelial NO synthase activity.
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Affiliation(s)
- Marit Westerterp
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY 10032, USA
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Tarling EJ, Bojanic DD, Tangirala RK, Wang X, Lovgren-Sandblom A, Lusis AJ, Bjorkhem I, Edwards PA. Impaired development of atherosclerosis in Abcg1-/- Apoe-/- mice: identification of specific oxysterols that both accumulate in Abcg1-/- Apoe-/- tissues and induce apoptosis. Arterioscler Thromb Vasc Biol 2010; 30:1174-80. [PMID: 20299684 DOI: 10.1161/atvbaha.110.205617] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To generate Abcg1(-/-) Apoe(-/-) mice to understand the mechanism and cell types involved in changes in atherosclerosis after loss of ABCG1. METHODS AND RESULTS ABCG1 is highly expressed in macrophages and endothelial cells, 2 cell types that play important roles in the development of atherosclerosis. Abcg1(-/-) Apoe(-/-) and Apoe(-/-) mice and recipient Apoe(-/-) mice that had undergone transplantation with bone marrow from Apoe(-/-) or Abcg1(-/-) Apoe(-/-) mice were fed a Western diet for 12 or 16 weeks before quantification of atherosclerotic lesions. These studies demonstrated that loss of ABCG1 from all tissues, or from only hematopoietic cells, was associated with significantly smaller lesions that contained increased numbers of TUNEL- and cleaved caspase 3-positive apoptotic Abcg1(-/-) macrophages. We also identified specific oxysterols that accumulate in the brains and macrophages of the Abcg1(-/-) Apoe(-/-) mice. These oxysterols promoted apoptosis and altered the expression of proapoptotic genes when added to macrophages in vitro. CONCLUSIONS Loss of ABCG1 from all tissues or from only hematopoietic cells results in smaller atherosclerotic lesions populated with increased apoptotic macrophages, by processes independent of ApoE. Specific oxysterols identified in tissues of Abcg1(-/-) Apoe(-/-) mice may be critical because they induce macrophage apoptosis and the expression of proapoptotic genes.
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Affiliation(s)
- Elizabeth J Tarling
- Department of Biological Chemistry, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA 90095-1737, USA
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Bojanic DD, Tarr PT, Gale GD, Smith DJ, Bok D, Chen B, Nusinowitz S, Lövgren-Sandblom A, Björkhem I, Edwards PA. Differential expression and function of ABCG1 and ABCG4 during development and aging. J Lipid Res 2010. [PMID: 19633360 DOI: 10.1194/jlr.m900250-jlr200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABCG1 and ABCG4 are highly homologous members of the ATP binding cassette (ABC) transporter family that regulate cellular cholesterol homeostasis. In adult mice, ABCG1 is known to be expressed in numerous cell types and tissues, whereas ABCG4 expression is limited to the central nervous system (CNS). Here, we show significant differences in expression of these two transporters during development. Examination of beta-galactosidase-stained tissue sections from Abcg1(-/-)LacZ and Abcg4(-/-)LacZ knockin mice shows that ABCG4 is highly but transiently expressed both in hematopoietic cells and in enterocytes during development. In contrast, ABCG1 is expressed in macrophages and in endothelial cells of both embryonic and adult liver. We also show that ABCG1 and ABCG4 are both expressed as early as E12.5 in the embryonic eye and developing CNS. Loss of both ABCG1 and ABCG4 results in accumulation in the retina and/or brain of oxysterols, in altered expression of liver X receptor and sterol-regulatory element binding protein-2 target genes, and in a stress response gene. Finally, behavioral tests show that Abcg4(-/-) mice have a general deficit in associative fear memory. Together, these data indicate that loss of ABCG1 and/or ABCG4 from the CNS results in changes in metabolic pathways and in behavior.
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Affiliation(s)
- Dragana D Bojanic
- Department of Biological Chemistry at UCLA Los Angeles, CA 90095, USA
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Armstrong AJ, Gebre AK, Parks JS, Hedrick CC. ATP-binding cassette transporter G1 negatively regulates thymocyte and peripheral lymphocyte proliferation. THE JOURNAL OF IMMUNOLOGY 2009; 184:173-83. [PMID: 19949102 DOI: 10.4049/jimmunol.0902372] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cholesterol is a key component of cell membranes and is essential for cell growth and proliferation. How the accumulation of cellular cholesterol affects lymphocyte development and function is not well understood. We demonstrate that ATP-binding cassette transporter G1 (ABCG1) regulates cholesterol homeostasis in thymocytes and peripheral CD4 T cells. Our work is the first to describe a cell type in Abcg1-deficient mice with such a robust change in cholesterol content and the expression of cholesterol metabolism genes. Abcg1-deficient mice display increased thymocyte cellularity and enhanced proliferation of thymocytes and peripheral T lymphocytes in vivo. The absence of ABCG1 in CD4 T cells results in hyperproliferation in vitro, but only when cells are stimulated through the TCR. We hypothesize that cholesterol accumulation in Abcg1(-/-) T cells alters the plasma membrane structure, resulting in enhanced TCR signaling for proliferation. Supporting this idea, we demonstrate that B6 T cells pretreated with soluble cholesterol have a significant increase in proliferation. Cholesterol accumulation in Abcg1(-/-) CD4 T cells results in enhanced basal phosphorylation levels of ZAP70 and ERK1/2. Furthermore, inhibition of ERK phosphorylation in TCR-stimulated Abcg1(-/-) T cells rescues the hyperproliferative phenotype. We describe a novel mechanism by which cholesterol can alter signaling from the plasma membrane to affect downstream signaling pathways and proliferation. These results implicate ABCG1 as an important negative regulator of lymphocyte proliferation through the maintenance of cellular cholesterol homeostasis.
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Affiliation(s)
- Allison J Armstrong
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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Yvan-Charvet L, Wang N, Tall AR. Role of HDL, ABCA1, and ABCG1 transporters in cholesterol efflux and immune responses. Arterioscler Thromb Vasc Biol 2009; 30:139-43. [PMID: 19797709 DOI: 10.1161/atvbaha.108.179283] [Citation(s) in RCA: 492] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Atherosclerosis has been characterized as a chronic inflammatory response to cholesterol deposition in arteries, but the mechanisms linking cholesterol accumulation in macrophage foam cells to inflammation are poorly understood. Macrophage cholesterol efflux occurs at all stages of atherosclerosis and protects cells from free cholesterol and oxysterol-induced toxicity. The ATP-binding cassette transporters ABCA1 and ABCG1 are responsible for the major part of macrophage cholesterol efflux to serum or HDL in macrophage foam cells, but other less efficient pathways such as passive efflux are also involved. Recent studies have shown that the sterol efflux activities of ABCA1 and ABCG1 modulate macrophage expression of inflammatory cytokines and chemokines as well as lymphocyte proliferative responses. In macrophages, transporter deficiency causes increased signaling via various Toll-like receptors including TLR4. These studies have shown that the traditional roles of HDL and ABC transporters in cholesterol efflux and reverse cholesterol transport are mechanistically linked to antiinflammatory and immunosuppressive functions of HDL. The underlying mechanisms may involve modulation of sterol levels and lipid organization in cell membranes.
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Affiliation(s)
- Laurent Yvan-Charvet
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 W 168th St, New York, NY 10032, USA.
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40
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Lack of Abcg1 results in decreased plasma HDL cholesterol levels and increased biliary cholesterol secretion in mice fed a high cholesterol diet. Atherosclerosis 2009; 206:141-7. [DOI: 10.1016/j.atherosclerosis.2009.02.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 02/12/2009] [Accepted: 02/16/2009] [Indexed: 01/26/2023]
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41
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Gelissen IC, Cartland S, Brown AJ, Sandoval C, Kim M, Dinnes DL, Lee Y, Hsieh V, Gaus K, Kritharides L, Jessup W. Expression and stability of two isoforms of ABCG1 in human vascular cells. Atherosclerosis 2009; 208:75-82. [PMID: 19651406 DOI: 10.1016/j.atherosclerosis.2009.06.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 06/12/2009] [Accepted: 06/28/2009] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate the expression of two ABCG1 isoforms that differ in the presence or absence of a 12 amino acid (AA) peptide between the ABC cassette and the transmembrane region, termed ABCG1(+12) and ABCG1(-12), respectively, in human vascular cells and tissues. METHODS AND RESULTS mRNA for both isoforms was expressed in human macrophages, vascular endothelial and smooth muscle cells as well as whole human spleen, lung, liver and brain tissue. However, ABCG1(+12) was not expressed in mouse tissues. 2D gel electrophoresis of ABCG1 protein indicated that both protein isoforms were expressed in human macrophages. Furthermore the half-lives of the two ABCG1 protein isoforms, stably expressed in CHOK1 cells, measured under basal conditions were different, suggesting the presence of a degradation or stabilising signal in or near the 12AA region of ABCG1(+12). CONCLUSION ABCG1(+12) is an isoform of ABCG1 exclusively expressed in human cells at the RNA and protein level. As ABCG1(+12) is not expressed in mice, although mouse models are widely used to elucidate the function of ABCG1, further investigations into the importance of this human ABCG1 isoform are warranted.
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Affiliation(s)
- Ingrid C Gelissen
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
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42
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Tarr PT, Tarling EJ, Bojanic DD, Edwards PA, Baldán Á. Emerging new paradigms for ABCG transporters. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1791:584-93. [PMID: 19416657 PMCID: PMC2698934 DOI: 10.1016/j.bbalip.2009.01.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 01/13/2009] [Accepted: 01/13/2009] [Indexed: 12/14/2022]
Abstract
Every cell is separated from its external environment by a lipid membrane. Survival depends on the regulated and selective transport of nutrients, waste products and regulatory molecules across these membranes, a process that is often mediated by integral membrane proteins. The largest and most diverse of these membrane transport systems is the ATP binding cassette (ABC) family of membrane transport proteins. The ABC family is a large evolutionary conserved family of transmembrane proteins (>250 members) present in all phyla, from bacteria to Homo sapiens, which require energy in the form of ATP hydrolysis to transport substrates against concentration gradients. In prokaryotes the majority of ABC transporters are involved in the transport of nutrients and other macromolecules into the cell. In eukaryotes, with the exception of the cystic fibrosis transmembrane conductance regulator (CFTR/ABCC7), ABC transporters mobilize substrates from the cytoplasm out of the cell or into specific intracellular organelles. This review focuses on the members of the ABCG subfamily of transporters, which are conserved through evolution in multiple taxa. As discussed below, these proteins participate in multiple cellular homeostatic processes, and functional mutations in some of them have clinical relevance in humans.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily G
- ATP Binding Cassette Transporter, Subfamily G, Member 1
- ATP Binding Cassette Transporter, Subfamily G, Member 2
- ATP Binding Cassette Transporter, Subfamily G, Member 5
- ATP Binding Cassette Transporter, Subfamily G, Member 8
- ATP-Binding Cassette Transporters/classification
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- ATP-Binding Cassette Transporters/physiology
- Animals
- Biological Transport
- Lipoproteins/genetics
- Lipoproteins/metabolism
- Lipoproteins/physiology
- Mice
- Mice, Knockout
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Affiliation(s)
- Paul T. Tarr
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - Elizabeth J. Tarling
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Dragana D. Bojanic
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Peter A. Edwards
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
| | - Ángel Baldán
- Edward A. Doisy Department of Biochemistry and Molecular Biology, DRC 321, Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, USA
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Pazienza V, Clément S, Pugnale P, Conzelmann S, Pascarella S, Mangia A, Negro F. Gene expression profile of Huh-7 cells expressing hepatitis C virus genotype 1b or 3a core proteins. Liver Int 2009; 29:661-9. [PMID: 18803589 DOI: 10.1111/j.1478-3231.2008.01866.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The liver disease expression in chronic hepatitis C patients is variable and may partially depend on the sequence of the infecting viral genotype. AIM To identify some hepatitis C virus (HCV) genotype-specific virus-host interactions potentially leading to clinically significant consequences. METHODS We compared the gene expression profile of Huh-7 cells transiently expressing the core protein of HCV genotype 1b and 3a using microarray technology. RESULTS Thirty-two genes were overexpressed in Huh-7 transfected with the HCV genotype 1b core protein and 57 genes in cells transfected with the genotype 3a core protein. On the other hand, we found 20 genes downregulated by core 1b and 31 genes by core 3a. These included genes involved in lipid transport and metabolism, cell cycle, immune response and insulin signalling. CONCLUSION The expression of HCV core proteins of different genotypes leads to a specific gene expression profile. This may account for the variable disease expression associated with HCV infection.
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Affiliation(s)
- Valerio Pazienza
- Division of Clinical Pathology, University Hospitals and University of Geneva, Geneva, Switzerland
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Furuyama S, Uehara Y, Zhang B, Baba Y, Abe S, Iwamoto T, Miura SI, Saku K. Genotypic Effect of ABCG1 Gene Promoter -257T>G Polymorphism on Coronary Artery Disease Severity in Japanese Men. J Atheroscler Thromb 2009; 16:194-200. [DOI: 10.5551/jat.e380] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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45
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Hirsch-Reinshagen V, Burgess BL, Wellington CL. Why lipids are important for Alzheimer disease? Mol Cell Biochem 2008; 326:121-9. [DOI: 10.1007/s11010-008-0012-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Accepted: 07/16/2008] [Indexed: 10/21/2022]
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Abstract
Mammalian cells have developed various responses to minimize accumulation of unesterified cholesterol, as the latter can result in cell toxicity and death [reviewed in this edition by Björkhem (Björkhem, I. 2009. Are side-chain oxidized oxysterols regulators also in vivo? J. Lipid Res. In press)]. These responses include esterification to sequester excess sterol in intracellular lipid droplets, repression of both cholesterol synthesis and LDL receptor expression (thus reducing endocytosis of LDL), and induction of a panoply of genes that promote sterol efflux and affect lipid metabolism. The nuclear receptor liver-X-receptor (LXR) functions as a cellular "sterol sensor" and plays a critical role in these latter transcriptional changes [reviewed in this edition by Glass (Shibata, N., and Glass C, K. 2009. Regulation of macrophage function in inflammation and atherosclerosis. J. Lipid Res. In press)]. Activation of LXR by either endogenous oxysterols or synthetic agonists induces the expression of many genes, including those encoding ATP-binding cassette (ABC) transporters ABCA1, ABCG1, ABCG5, and ABCG8. As discussed below, these four proteins function to promote sterol efflux from cells.
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Affiliation(s)
- Angel Baldán
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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47
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Burgess B, Naus K, Chan J, Hirsch-Reinshagen V, Tansley G, Matzke L, Chan B, Wilkinson A, Fan J, Donkin J, Balik D, Tanaka T, Ou G, Dyer R, Innis S, McManus B, Lütjohann D, Wellington C. Overexpression of Human ABCG1 Does Not Affect Atherosclerosis in Fat-Fed ApoE-Deficient Mice. Arterioscler Thromb Vasc Biol 2008; 28:1731-7. [DOI: 10.1161/atvbaha.108.168542] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
The purpose of this study was to evaluate the effects of whole body overexpression of human ABCG1 on atherosclerosis in apoE
−/−
mice.
Methods and Results—
We generated BAC transgenic mice in which human ABCG1 is expressed from endogenous regulatory signals, leading to a 3- to 7-fold increase in ABCG1 protein across various tissues. Although the ABCG1 BAC transgene rescued lung lipid accumulation in ABCG1
−/−
mice, it did not affect plasma lipid levels, macrophage cholesterol efflux to HDL, atherosclerotic lesion area in apoE
−/−
mice, or levels of tissue cholesterol, cholesterol ester, phospholipids, or triglycerides. Subtle changes in sterol biosynthetic intermediate levels were observed in liver, with chow-fed ABCG1 BAC Tg mice showing a nonsignificant trend toward decreased levels of lathosterol, lanosterol, and desmosterol, and fat-fed mice exhibiting significantly elevated levels of each intermediate. These changes were insufficient to alter ABCA1 expression in liver.
Conclusions—
Transgenic human ABCG1 does not influence atherosclerosis in apoE
−/−
mice but may participate in the regulation of tissue cholesterol biosynthesis.
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Affiliation(s)
- Braydon Burgess
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Kathryn Naus
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Jeniffer Chan
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Veronica Hirsch-Reinshagen
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Gavin Tansley
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Lisa Matzke
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Benny Chan
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Anna Wilkinson
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Jianjia Fan
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - James Donkin
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Danielle Balik
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Tracie Tanaka
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - George Ou
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Roger Dyer
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Sheila Innis
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Bruce McManus
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Dieter Lütjohann
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
| | - Cheryl Wellington
- From the Department of Pathology and Laboratory Medicine (B.B., K.N., J.C., V.H.-R., G.T., A.W., J.F., J.D., D.B., T.T., G.O., C.W.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; ICapture Centre (L.M., B.M.), University of British Columbia, Vancouver, Canada; the Department of Pediatrics (B.C., R.D., S.I.), Child and Family Research Institute, University of British Columbia, Vancouver, Canada; and the Department of Clinical Pharmacology (D.L.), University
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48
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Abstract
PURPOSE OF REVIEW The lipid efflux pathway is important for both HDL formation and the reverse cholesterol transport pathway. This review is focused on recent findings on the mechanism of lipid efflux and its regulation, particularly in macrophages. RECENT FINDINGS Significant progress has been made on understanding the sequence of events that accompany the interaction of apolipoproteins A-I with cell surface ATP-binding cassette transporter A1 and its subsequent lipidation. Continued research on the regulation of ATP-binding cassette transporter A1 and ATP-binding cassette transporter G1 expression and traffic has also generated new paradigms for the control of lipid efflux from macrophages and its contribution to reverse cholesterol transport. In addition, the mobilization of cholesteryl esters from lipid droplets represents a new step in the control of cholesterol efflux. SUMMARY The synergy between lipid transporters is a work in progress, but its importance in reverse cholesterol transport is clear. The regulation of efflux implies both the regulation of relevant transporters and the cellular trafficking of cholesterol.
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Affiliation(s)
- Yves L Marcel
- Lipoprotein and Atherosclerosis Research Group, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
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49
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Mukhamedova N, Escher G, D'Souza W, Tchoua U, Grant A, Krozowski Z, Bukrinsky M, Sviridov D. Enhancing apolipoprotein A-I-dependent cholesterol efflux elevates cholesterol export from macrophages in vivo. J Lipid Res 2008; 49:2312-22. [PMID: 18622028 DOI: 10.1194/jlr.m800095-jlr200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eight proteins potentially involved in cholesterol efflux [ABCA1, ABCG1, CYP27A1, phospholipid transfer protein (PLTP), scavenger receptor type BI (SR-BI), caveolin-1, cholesteryl ester transfer protein, and apolipoprotein A-I (apoA-I)] were overexpressed alone or in combination in RAW 264.7 macrophages. When apoA-I was used as an acceptor, overexpression of the combination of ABCA1, CYP27A1, PLTP, and SR-BI (Combination I) enhanced the efflux by 4.3-fold. It was established that the stimulation of efflux was due to increased abundance of ABCA1 and increased apoA-I binding to non-ABCA1 sites on macrophages. This combination caused only a small increase of the efflux to isolated HDL. When HDL was used as an acceptor, overexpression of caveolin-1 or a combination of caveolin-1 and SR-BI (Combination II) was the most active, doubling the efflux to HDL, without affecting the efflux to apoA-I. When tested in the in vivo mouse model of cholesterol efflux, overexpression of ABCA1 and Combination I elevated cholesterol export from macrophages to plasma, liver, and feces, whereas overexpression of caveolin-1 or Combination II did not have an effect. We conclude that pathways of cholesterol efflux using apoA-I as an acceptor make a predominant contribution to cholesterol export from macrophages in vivo.
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50
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Zhang JR, Coleman T, Langmade SJ, Scherrer DE, Lane L, Lanier MH, Feng C, Sands MS, Schaffer JE, Semenkovich CF, Ory DS. Niemann-Pick C1 protects against atherosclerosis in mice via regulation of macrophage intracellular cholesterol trafficking. J Clin Invest 2008; 118:2281-90. [PMID: 18483620 DOI: 10.1172/jci32561] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 04/09/2008] [Indexed: 11/17/2022] Open
Abstract
Niemann-Pick C1 (NPC1) is a key participant in cellular cholesterol trafficking. Loss of NPC1 function leads to defective suppression of SREBP-dependent gene expression and failure to appropriately activate liver X receptor-mediated (LXR-mediated) pathways, ultimately resulting in intracellular cholesterol accumulation. To determine whether NPC1 contributes to regulation of macrophage sterol homeostasis in vivo, we examined the effect of NPC1 deletion in BM-derived cells on atherosclerotic lesion development in the Ldlr-/- mouse model of atherosclerosis. High-fat diet-fed chimeric Npc1-/- mice reconstituted with Ldlr-/-Npc1-/- macrophages exhibited accelerated atherosclerosis despite lower serum cholesterol compared with mice reconstituted with wild-type macrophages. The discordance between the low serum lipoprotein levels and the presence of aortic atherosclerosis suggested that intrinsic alterations in macrophage sterol metabolism in the chimeric Npc1-/- mice played a greater role in atherosclerotic lesion formation than did serum lipoprotein levels. Macrophages from chimeric Npc1-/- mice showed decreased synthesis of 27-hydroxycholesterol (27-HC), an endogenous LXR ligand; decreased expression of LXR-regulated cholesterol transporters; and impaired cholesterol efflux. Lower 27-HC levels were associated with elevated cholesterol oxidation products in macrophages and plasma of chimeric Npc1-/- mice and with increased oxidative stress. Our results demonstrate that NPC1 serves an atheroprotective role in mice through regulation of LXR-dependent cholesterol efflux and mitigation of cholesterol-induced oxidative stress in macrophages.
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Affiliation(s)
- Jessie R Zhang
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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