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Mikołajczyk-Stecyna J, Zuk E, Chmurzynska A, Blatkiewicz M, Jopek K, Rucinski M. The effects of exposure to and timing of a choline-deficient diet during pregnancy and early postnatal life on the skeletal muscle transcriptome of the offspring. Clin Nutr 2024; 43:1503-1515. [PMID: 38729079 DOI: 10.1016/j.clnu.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/09/2024] [Accepted: 05/02/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND & AIMS Nonalcoholic fatty liver disease (NAFLD) is related to muscle loss, but the precise mechanism underlying this association remains unclear. The aim of the present study was thus to determine the influence of maternal fatty liver and dietary choline deficiency during pregnancy and/or lactation periods on the skeletal muscle gene expression profile among 24-day-old male rat offspring. METHODS Histological examination of skeletal muscle tissue specimens obtained from offspring of dams suffering from fatty liver, provided with proper choline intake during pregnancy and lactation (NN), fed a choline-deficient diet during both periods (DD), deprived of choline only during pregnancy (DN), or only during lactation (ND), was performed. The global transcriptome pattern was assessed using a microarray approach (Affymetrix® Rat Gene 2.1 ST Array Strip). The relative expression of selected genes was validated by real-time PCR (qPCR). RESULTS Morphological differences in fat accumulation in skeletal muscle related to choline supply were observed. The global gene expression profile was consistent with abnormal morphological changes. Mettl21c gene was overexpressed in all choline-deficient groups compared to the NN group, while two genes, Cdkn1a and S100a4, were downregulated. Processes of protein biosynthesis were upregulated, and processes related to cell proliferation and lipid metabolism were inhibited in DD, DN, and ND groups compared to the NN group. CONCLUSIONS Prenatal and early postnatal exposure to fatty liver and dietary choline deficiency leads to changes in the transcriptome profile in skeletal muscle of 24-day old male rat offspring and is associated with muscle damage, but the mechanism of it seems to be different at different developmental stages of life. Adequate choline intake during pregnancy and lactation can prevent severe muscle disturbance in the progeny of females suffering from fatty liver.
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Affiliation(s)
| | - Ewelina Zuk
- Poznań University of Life Sciences, Department of Human Nutrition and Dietetics, Poznań, Poland
| | - Agata Chmurzynska
- Poznań University of Life Sciences, Department of Human Nutrition and Dietetics, Poznań, Poland
| | - Malgorzata Blatkiewicz
- Poznań University of Medical Sciences, Department of Histology and Embryology, Poznań, Poland
| | - Karol Jopek
- Poznań University of Medical Sciences, Department of Histology and Embryology, Poznań, Poland
| | - Marcin Rucinski
- Poznań University of Medical Sciences, Department of Histology and Embryology, Poznań, Poland
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2
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Abstract
PURPOSE To investigate the associations of Single Nucleotide Polymorphisms (SNPs) in the SNTB1 gene with high myopia in a Han Chinese population. MATERIALS AND METHODS Based on previous studies, four SNPs from the SNTB1 gene were chosen for genotyping. This is a case-control genetic association study comprising 193 high myopia participants and 135 normal emmetropic controls from a Han Chinese population. Allelic frequencies of the SNPs and haplotypes were compared to assess the associations of the SNPs with high myopia and axial length (AL). RESULTS The SNPs rs7839488 (effect allele: A; OR = 0.685), rs4395927 (effect allele: T; OR = 0.692), and rs6469937 (effect allele: A; OR = 0.683) displayed significant associations with high myopia initially (P = .044, 0.049, and 0.035, respectively), but did not withstand permutation testing (all Ppermutation>0.05). rs6469937 displayed associations with high myopia in the dominant model (AG+AA: OR = 0.609) against GG (reference). rs6469937 was also associated with AL in the dominant model (AG+AA: Beta = -0.58) against GG (reference). The haplotype analysis demonstrated ATGA as the protective haplotype against high myopia, which remained statistically significant in permutation testing (Ppermutation = 0.045). CONCLUSIONS Our findings are suggestive that SNTB1 is associated with high myopia in a Han Chinese population.
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Affiliation(s)
- Kai Xiong Cheong
- Singapore Eye Research Institute, Singapore National Eye Centre , Singapore.,Vision Performance Centre, Military Medicine Institute, Singapore Armed Forces , Singapore
| | - Rita Yu Yin Yong
- DSO National Laboratories, Defence Medical and Environmental Research Institute , Singapore
| | - Mellisa Mei Hui Tan
- Vision Performance Centre, Military Medicine Institute, Singapore Armed Forces , Singapore
| | | | - Bryan Chin Hou Ang
- Vision Performance Centre, Military Medicine Institute, Singapore Armed Forces , Singapore.,National Healthcare Group Eye Institute, Tan Tock Seng Hospital , Singapore
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3
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Wang D, Hiebl V, Xu T, Ladurner A, Atanasov AG, Heiss EH, Dirsch VM. Impact of natural products on the cholesterol transporter ABCA1. JOURNAL OF ETHNOPHARMACOLOGY 2020; 249:112444. [PMID: 31805338 DOI: 10.1016/j.jep.2019.112444] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 11/13/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE In different countries and areas of the world, traditional medicine has been and is still used for the treatment of various disorders, including chest pain or liver complaints, of which we now know that they can be linked with altered lipid and cholesterol homeostasis. As ATP-binding cassette transporter A1 (ABCA1) plays an essential role in cholesterol metabolism, its modulation may be one of the molecular mechanisms responsible for the experienced benefit of traditional recipes. Intense research activity has been dedicated to the identification of natural products from traditional medicine that regulate ABCA1 expression. AIMS OF THE REVIEW This review surveys natural products, originating from ethnopharmacologically used plants, fungi or marine sources, which influence ABCA1 expression, providing a reference for future study. MATERIALS AND METHODS Information on regulation of ABCA1 expression by natural compounds from traditional medicine was extracted from ancient and modern books, materia medica, and electronic databases (PubMed, Google Scholar, Science Direct, and ResearchGate). RESULTS More than 60 natural compounds from traditional medicine, especially traditional Chinese medicine (TCM), are reported to regulate ABCA1 expression in different in vitro and in vivo models (such as cholesterol efflux and atherosclerotic animal models). These active compounds belong to the classes of polyketides, terpenoids, phenylpropanoids, tannins, alkaloids, steroids, amino acids and others. Several compounds appear very promising in vivo, which need to be further investigated in animal models of diseases related to ABCA1 or in clinical studies. CONCLUSION Natural products from traditional medicine constitute a large promising pool for compounds that regulate ABCA1 expression, and thus may prevent/treat diseases related to cholesterol metabolism, like atherosclerosis or Alzheimer's disease. In many cases, the molecular mechanisms of these natural products remain to be investigated.
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Affiliation(s)
- Dongdong Wang
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria; The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Fei Shan Jie 32, 550003, Guiyang, China
| | - Verena Hiebl
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Tao Xu
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Fei Shan Jie 32, 550003, Guiyang, China
| | - Angela Ladurner
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Atanas G Atanasov
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria; Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, ul. Postepu 36A, 05-552, Jastrzębiec, Poland; Institute of Neurobiology, Bulgarian Academy of Sciences, 23 Acad. G. Bonchevstr., 1113, Sofia, Bulgaria
| | - Elke H Heiss
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Verena M Dirsch
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
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4
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Abstract
Atherosclerosis is a vascular disease responsible for acute heart attacks and stroke, which are leading causes of death not only in industrialized countries but also worldwide, and the number of patients afflicted by this disease has been increasing in Japan. High-density lipoprotein (HDL) is the plasma lipoprotein that carries what is often called your "good cholesterol" through the blood. This good cholesterol moniker is associated with HDL because higher circulating levels of this lipoprotein are associated with a well-known reduction in the risk of arteriosclerosis. Moreover, many protective mechanisms by which HDL could reduce atherosclerosis are described, including reverse cholesterol transport, along with anti-oxidant, anti-inflammatory and anti-thrombosis activities. However, HDL-modulating therapies to lower cardiovascular risk are not yet available. It has recently been proposed that apolipoprotein A-I (apoA-I) binding protein (AIBP) enhances HDL function by accelerating lipid release from cells and reducing associated inflammatory processes. In this context, our research is focused on the function of HDL-related proteins, such as proteins that regulate HDL production (ATP-binding cassette transporters), and HDL-binding proteins. We expect that these studies could eventually help in the development of HDL-related prognostic and therapeutic strategies to reduce the burden of cardiovascular disease in the future.
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Affiliation(s)
- Keiichiro Okuhira
- Department of Molecular Physical Pharmaceutics, Institute of Biomedical Sciences, Tokushima University Graduate School
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5
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Okamoto Y, Tomioka M, Ogasawara F, Nagaiwa K, Kimura Y, Kioka N, Ueda K. C-terminal of ABCA1 separately regulates cholesterol floppase activity and cholesterol efflux activity. Biosci Biotechnol Biochem 2019; 84:764-773. [PMID: 31814539 DOI: 10.1080/09168451.2019.1700775] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
ATP-Binding Cassette A1 (ABCA1) is a key lipid transporter for cholesterol homeostasis. We recently reported that ABCA1 not only exports excess cholesterol in an apoA-I dependent manner, but that it also flops cholesterol from the inner to the outer leaflet of the plasma membrane. However, the relationship between these two activities of ABCA1 is still unclear. In this study, we analyzed the subcellular localization of ABCA1 by using a newly generated monoclonal antibody against its extracellular domain and the functions of eleven chimera proteins, in which the C-terminal domain of ABCA1 was replaced with those of the other ABCA subfamily members. We identified two motifs important for the functions of ABCA1. Three periodically repeated leucine residues were necessary for the cholesterol floppase activity but not the cholesterol efflux activity, while a VFVNFA motif was essential for both activities of ABCA1. These results suggest that the C-terminal of ABCA1 separately regulates the cholesterol floppase activity and the cholesterol efflux activity.
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Affiliation(s)
- Yusuke Okamoto
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Maiko Tomioka
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Fumihiko Ogasawara
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
| | - Kota Nagaiwa
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yasuhisa Kimura
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Noriyuki Kioka
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.,Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
| | - Kazumitsu Ueda
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
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6
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Su S, Li H, Du F, Zhang C, Li X, Jing X, Liu L, Li Z, Yang X, Xu P, Yuan X, Zhu J, Bouzoualegh R. Combined QTL and Genome Scan Analyses With the Help of 2b-RAD Identify Growth-Associated Genetic Markers in a New Fast-Growing Carp Strain. Front Genet 2018; 9:592. [PMID: 30581452 PMCID: PMC6293859 DOI: 10.3389/fgene.2018.00592] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 11/15/2018] [Indexed: 11/17/2022] Open
Abstract
Common carp is one of the oldest and most popular cultured freshwater fish species both globally and in China. In a previous study, we used a carp strain with a long breeding tradition in China, named Huanghe, to create a new fast-growing strain by selection for fast growth for 6 years. The growth performance at 8 months of age has been improved by 20.84%. To achieve this, we combined the best linear unbiased prediction with marker-assisted selection techniques. Recent progress in genome-wide association studies and genomic selection in livestock breeding inspired common carp breeders to consider genome-based breeding approaches. In this study, we developed a 2b-RAD sequence assay as a means of investigating the quantitative trait loci in common carp. A total of 4,953,017,786 clean reads were generated for 250 specimens (average reads/specimen = 19,812,071) with BsaXI Restriction Enzyme. From these, 56,663 SNPs were identified, covering 50 chromosomes and 3,377 scaffolds. Principal component analysis indicated that selection and control groups are relatively clearly distinct. Top 1% of Fst values was selected as the threshold signature of artificial selection. Among the 244 identified loci, genes associated with sex-related factors and nutritional metabolism (especially fat metabolism) were annotated. Eighteen QTL were associated with growth parameters. Body length at 3 months of age and body weight (both at 3 and 8 months) were controlled by polygenic effects, but body size (length, depth, width) at 8 months of age was controlled mainly by several loci with major effects. Importantly, a single shared QTL (IGF2 gene) partially controlled the body length, depth, and width. By merging the above results, we concluded that mainly the genes related to neural pathways, sex and fatty acid metabolism contributed to the improved growth performance of the new Huanghe carp strain. These findings are one of the first investigations into the potential use of genomic selection in the breeding of common carp. Moreover, our results show that combining the Fst, QTL mapping and CRISPR–Cas9 methods can be an effective way to identify important novel candidate molecular markers in economic breeding programs.
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Affiliation(s)
- Shengyan Su
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.,Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Hengde Li
- Ministry of Agriculture Key Laboratory of Aquatic Genomics, CAFS Key Laboratory of Aquatic Genomics and Beijing Key Laboratory of Fishery Biotechnology, Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Fukuan Du
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
| | - Chengfeng Zhang
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.,Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Xinyuan Li
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Xiaojun Jing
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.,Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Liyue Liu
- China Zebrafish Resource Center, Wuhan, China
| | - Zhixun Li
- Henan Academy of Fishery Sciences, Zhengzhou, China
| | - Xingli Yang
- Henan Academy of Fishery Sciences, Zhengzhou, China
| | - Pao Xu
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.,Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Xinhua Yuan
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.,Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Jian Zhu
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.,Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Raouf Bouzoualegh
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
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7
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Liu M, Mei X, Herscovitz H, Atkinson D. N-terminal mutation of apoA-I and interaction with ABCA1 reveal mechanisms of nascent HDL biogenesis. J Lipid Res 2018; 60:44-57. [PMID: 30249788 DOI: 10.1194/jlr.m084376] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 09/21/2018] [Indexed: 12/25/2022] Open
Abstract
ApoA-I and ABCA1 play important roles in nascent HDL (nHDL) biogenesis, the first step in the pathway of reverse cholesterol transport that protects against cardiovascular disease. On the basis of the crystal structure of a C-terminally truncated form of apoA-I[Δ(185-243)] determined in our laboratory, we hypothesized that opening the N-terminal helix bundle would facilitate lipid binding. To that end, we structurally designed a mutant (L38G/K40G) to destabilize the N-terminal helical bundle at the first hinge region. Conformational characterization of this mutant in solution revealed minimally reduced α-helical content, a less-compact overall structure, and increased lipid-binding ability. In solution-binding studies, apoA-I and purified ABCA1 also showed direct binding between them. In ABCA1-transfected HEK293 cells, L38G/K40G had a significantly enhanced ability to form nHDL, which suggests that a destabilized N-terminal bundle facilitates nHDL formation. The total cholesterol efflux from ABCA1-transfected HEK293 cells was unchanged in mutant versus WT apoA-I, though, which suggests that cholesterol efflux and nHDL particle formation might be uncoupled events. Analysis of the particles in the efflux media revealed a population of apoA-I-free lipid particles along with nHDL. This model improves knowledge of nHDL formation for future research.
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Affiliation(s)
- Minjing Liu
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Xiaohu Mei
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | | | - David Atkinson
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
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8
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Intracellular and Plasma Membrane Events in Cholesterol Transport and Homeostasis. J Lipids 2018; 2018:3965054. [PMID: 30174957 PMCID: PMC6106919 DOI: 10.1155/2018/3965054] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/26/2018] [Indexed: 12/13/2022] Open
Abstract
Cholesterol transport between intracellular compartments proceeds by both energy- and non-energy-dependent processes. Energy-dependent vesicular traffic partly contributes to cholesterol flux between endoplasmic reticulum, plasma membrane, and endocytic vesicles. Membrane contact sites and lipid transfer proteins are involved in nonvesicular lipid traffic. Only “active" cholesterol molecules outside of cholesterol-rich regions and partially exposed in water phase are able to fast transfer. The dissociation of partially exposed cholesterol molecules in water determines the rate of passive aqueous diffusion of cholesterol out of plasma membrane. ATP hydrolysis with concomitant conformational transition is required to cholesterol efflux by ABCA1 and ABCG1 transporters. Besides, scavenger receptor SR-B1 is involved also in cholesterol efflux by facilitated diffusion via hydrophobic tunnel within the molecule. Direct interaction of ABCA1 with apolipoprotein A-I (apoA-I) or apoA-I binding to high capacity binding sites in plasma membrane is important in cholesterol escape to free apoA-I. ABCG1-mediated efflux to fully lipidated apoA-I within high density lipoprotein particle proceeds more likely through the increase of “active” cholesterol level. Putative cholesterol-binding linear motifs within the structure of all three proteins ABCA1, ABCG1, and SR-B1 are suggested to contribute to the binding and transfer of cholesterol molecules from cytoplasmic to outer leaflets of lipid bilayer. Together, plasma membrane events and intracellular cholesterol metabolism and traffic determine the capacity of the cell for cholesterol efflux.
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9
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Yamauchi Y, Rogers MA. Sterol Metabolism and Transport in Atherosclerosis and Cancer. Front Endocrinol (Lausanne) 2018; 9:509. [PMID: 30283400 PMCID: PMC6157400 DOI: 10.3389/fendo.2018.00509] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/14/2018] [Indexed: 01/22/2023] Open
Abstract
Cholesterol is a vital lipid molecule for mammalian cells, regulating fluidity of biological membranes, and serving as an essential constituent of lipid rafts. Mammalian cells acquire cholesterol from extracellular lipoproteins and from de novo synthesis. Cholesterol biosynthesis generates various precursor sterols. Cholesterol undergoes metabolic conversion into oxygenated sterols (oxysterols), bile acids, and steroid hormones. Cholesterol intermediates and metabolites have diverse and important cellular functions. A network of molecular machineries including transcription factors, protein modifiers, sterol transporters/carriers, and sterol sensors regulate sterol homeostasis in mammalian cells and tissues. Dysfunction in metabolism and transport of cholesterol, sterol intermediates, and oxysterols occurs in various pathophysiological settings such as atherosclerosis, cancers, and neurodegenerative diseases. Here we review the cholesterol, intermediate sterol, and oxysterol regulatory mechanisms and intracellular transport machineries, and discuss the roles of sterols and sterol metabolism in human diseases.
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Affiliation(s)
- Yoshio Yamauchi
- Nutri-Life Science Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
- *Correspondence: Yoshio Yamauchi
| | - Maximillian A. Rogers
- Division of Cardiovascular Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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10
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Spracklen CN, Chen P, Kim YJ, Wang X, Cai H, Li S, Long J, Wu Y, Wang YX, Takeuchi F, Wu JY, Jung KJ, Hu C, Akiyama K, Zhang Y, Moon S, Johnson TA, Li H, Dorajoo R, He M, Cannon ME, Roman TS, Salfati E, Lin KH, Guo X, Sheu WHH, Absher D, Adair LS, Assimes TL, Aung T, Cai Q, Chang LC, Chen CH, Chien LH, Chuang LM, Chuang SC, Du S, Fan Q, Fann CSJ, Feranil AB, Friedlander Y, Gordon-Larsen P, Gu D, Gui L, Guo Z, Heng CK, Hixson J, Hou X, Hsiung CA, Hu Y, Hwang MY, Hwu CM, Isono M, Juang JMJ, Khor CC, Kim YK, Koh WP, Kubo M, Lee IT, Lee SJ, Lee WJ, Liang KW, Lim B, Lim SH, Liu J, Nabika T, Pan WH, Peng H, Quertermous T, Sabanayagam C, Sandow K, Shi J, Sun L, Tan PC, Tan SP, Taylor KD, Teo YY, Toh SA, Tsunoda T, van Dam RM, Wang A, Wang F, Wang J, Wei WB, Xiang YB, Yao J, Yuan JM, Zhang R, Zhao W, Chen YDI, Rich SS, Rotter JI, Wang TD, Wu T, Lin X, Han BG, Tanaka T, Cho YS, Katsuya T, Jia W, Jee SH, Chen YT, Kato N, Jonas JB, Cheng CY, Shu XO, He J, Zheng W, Wong TY, Huang W, Kim BJ, Tai ES, Mohlke KL, Sim X. Association analyses of East Asian individuals and trans-ancestry analyses with European individuals reveal new loci associated with cholesterol and triglyceride levels. Hum Mol Genet 2017; 26:1770-1784. [PMID: 28334899 DOI: 10.1093/hmg/ddx062] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 02/16/2017] [Indexed: 12/28/2022] Open
Abstract
Large-scale meta-analyses of genome-wide association studies (GWAS) have identified >175 loci associated with fasting cholesterol levels, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). With differences in linkage disequilibrium (LD) structure and allele frequencies between ancestry groups, studies in additional large samples may detect new associations. We conducted staged GWAS meta-analyses in up to 69,414 East Asian individuals from 24 studies with participants from Japan, the Philippines, Korea, China, Singapore, and Taiwan. These meta-analyses identified (P < 5 × 10-8) three novel loci associated with HDL-C near CD163-APOBEC1 (P = 7.4 × 10-9), NCOA2 (P = 1.6 × 10-8), and NID2-PTGDR (P = 4.2 × 10-8), and one novel locus associated with TG near WDR11-FGFR2 (P = 2.7 × 10-10). Conditional analyses identified a second signal near CD163-APOBEC1. We then combined results from the East Asian meta-analysis with association results from up to 187,365 European individuals from the Global Lipids Genetics Consortium in a trans-ancestry meta-analysis. This analysis identified (log10Bayes Factor ≥6.1) eight additional novel lipid loci. Among the twelve total loci identified, the index variants at eight loci have demonstrated at least nominal significance with other metabolic traits in prior studies, and two loci exhibited coincident eQTLs (P < 1 × 10-5) in subcutaneous adipose tissue for BPTF and PDGFC. Taken together, these analyses identified multiple novel lipid loci, providing new potential therapeutic targets.
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Affiliation(s)
| | - Peng Chen
- Saw Swee Hock School of Public Health, National University Health System, National University of Singapore, Singapore, Singapore.,Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, China
| | - Young Jin Kim
- Division of Structural and Functional Genomics, Center for Genome Science, Korean National Institute of Health, Osong, Chungchungbuk-do, South Korea
| | - Xu Wang
- Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Hui Cai
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Shengxu Li
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Jirong Long
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ying Wu
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Ya Xing Wang
- Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | | | - Jer-Yuarn Wu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Keum-Ji Jung
- Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, South Korea
| | - Cheng Hu
- Shanghai Diabetes Institute, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Koichi Akiyama
- National Center for Global Health and Medicine, Tokyo, Japan
| | - Yonghong Zhang
- Department of Epidemiology, School of Public Health and Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Medical College of Soochow University, Suzhou, China
| | - Sanghoon Moon
- Division of Structural and Functional Genomics, Center for Genome Science, Korean National Institute of Health, Osong, Chungchungbuk-do, South Korea
| | - Todd A Johnson
- Laboratory for Medical Science Mathematics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Huaixing Li
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, China
| | - Rajkumar Dorajoo
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Meian He
- Department of Occupational and Environmental Health and State Key Laboratory of Environmental Health for Incubating, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Maren E Cannon
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Tamara S Roman
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Elias Salfati
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Keng-Hung Lin
- Department of Ophthalmology, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Xiuqing Guo
- Department of Pediatrics, Institute for Translational Genomics and Population Sciences, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Wayne H H Sheu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan.,School of Medicine, National Defense Medical Center, Taipei, Taiwan.,Institute of Medical Technology, National Chung-Hsing University, Taichung, Taiwan
| | - Devin Absher
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - Linda S Adair
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | | | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Duke-NUS Medical School Singapore, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Qiuyin Cai
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Li-Ching Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chien-Hsiun Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Li-Hsin Chien
- Institute of Population Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Lee-Ming Chuang
- Division of Endocrinology & Metabolism, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.,College of Medicine, National Taiwan University, Taipei, Taiwan.,Institute of Preventive Medicine, School of Public Health, National Taiwan University, Taipei, Taiwan
| | - Shu-Chun Chuang
- Institute of Population Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Shufa Du
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.,Carolina Population Center, University of North Carolina, Chapel Hill, NC, USA
| | - Qiao Fan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Cathy S J Fann
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Alan B Feranil
- USC-Office of Population Studies Foundation, Inc, University of San Carlos, Cebu City, Philippines.,Department of Anthropology, Sociology, and History, University of San Carlos, Cebu City, Philippines
| | - Yechiel Friedlander
- Unit of Epidemiology, Hebrew University-Hadassah Braun School of Public Health, Jerusalem, Israel
| | - Penny Gordon-Larsen
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.,Carolina Population Center, University of North Carolina, Chapel Hill, NC, USA
| | - Dongfeng Gu
- Department of Epidemiology and Population Genetics, Fuwai Hospital, Beijing, China
| | - Lixuan Gui
- Department of Occupational and Environmental Health and State Key Laboratory of Environmental Health for Incubating, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhirong Guo
- Department of Epidemiology, School of Public Health and Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Medical College of Soochow University, Suzhou, China
| | - Chew-Kiat Heng
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore, Singapore
| | - James Hixson
- Human Genetics Center, University of Texas School of Public Health, Houston, TX, USA
| | - Xuhong Hou
- Shanghai Diabetes Institute, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Chao Agnes Hsiung
- Institute of Population Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Yao Hu
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, China
| | - Mi Yeong Hwang
- Division of Structural and Functional Genomics, Center for Genome Science, Korean National Institute of Health, Osong, Chungchungbuk-do, South Korea
| | - Chii-Min Hwu
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Section of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Masato Isono
- National Center for Global Health and Medicine, Tokyo, Japan
| | - Jyh-Ming Jimmy Juang
- College of Medicine, National Taiwan University, Taipei, Taiwan.,Cardiovascular Center and Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Chiea-Chuen Khor
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore.,Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Yun Kyoung Kim
- Division of Structural and Functional Genomics, Center for Genome Science, Korean National Institute of Health, Osong, Chungchungbuk-do, South Korea
| | - Woon-Puay Koh
- Saw Swee Hock School of Public Health, National University Health System, National University of Singapore, Singapore, Singapore.,Duke-NUS Medical School Singapore, Singapore, Singapore
| | - Michiaki Kubo
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - I-Te Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan.,School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Sun-Ju Lee
- Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, South Korea
| | - Wen-Jane Lee
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan.,Department of Social Work, Tunghai University, Taichung, Taiwan
| | - Kae-Woei Liang
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan.,Department of Medicine, China Medical University, Taichung, Taiwan
| | - Blanche Lim
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Sing-Hui Lim
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Jianjun Liu
- Saw Swee Hock School of Public Health, National University Health System, National University of Singapore, Singapore, Singapore.,Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Toru Nabika
- Department of Functional Pathology, Shimane University School of Medicine, Izumo, Japan
| | - Wen-Harn Pan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hao Peng
- Department of Epidemiology, School of Public Health and Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Medical College of Soochow University, Suzhou, China
| | - Thomas Quertermous
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Charumathi Sabanayagam
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Duke-NUS Medical School Singapore, Singapore, Singapore
| | - Kevin Sandow
- Department of Pediatrics, Institute for Translational Genomics and Population Sciences, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Jinxiu Shi
- Department of Genetics, Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center and Shanghai Industrial Technology Institute, Shanghai, China
| | - Liang Sun
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, China
| | - Pok Chien Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Shu-Pei Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Kent D Taylor
- Department of Pediatrics, Institute for Translational Genomics and Population Sciences, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Yik-Ying Teo
- Saw Swee Hock School of Public Health, National University Health System, National University of Singapore, Singapore, Singapore.,Life Sciences Institute, National University of Singapore, Singapore, Singapore.,Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore.,NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, Singapore.,Department of Statistics and Applied Probability, National University of Singapore, Singapore, Singapore
| | - Sue-Anne Toh
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Tatsuhiko Tsunoda
- Laboratory for Medical Science Mathematics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Department of Medical Science Mathematics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Rob M van Dam
- Saw Swee Hock School of Public Health, National University Health System, National University of Singapore, Singapore, Singapore
| | - Aili Wang
- Department of Epidemiology, School of Public Health and Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Medical College of Soochow University, Suzhou, China
| | - Feijie Wang
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, China
| | - Jie Wang
- Shanghai Diabetes Institute, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Wen Bin Wei
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Visual Science Key Lab, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Capital Medical University, Beijing, China
| | - Yong-Bing Xiang
- Department of Epidemiology, Shanghai Cancer Institute, Shanghai, China
| | - Jie Yao
- Department of Pediatrics, Institute for Translational Genomics and Population Sciences, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Jian-Min Yuan
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.,Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
| | - Rong Zhang
- Shanghai Diabetes Institute, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Wanting Zhao
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Duke-NUS Medical School Singapore, Singapore, Singapore
| | - Yii-Der Ida Chen
- Department of Pediatrics, Institute for Translational Genomics and Population Sciences, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Stephen S Rich
- Center for Public Health Genomics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jerome I Rotter
- Department of Pediatrics, Institute for Translational Genomics and Population Sciences, LABioMed at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Tzung-Dau Wang
- College of Medicine, National Taiwan University, Taipei, Taiwan.,Cardiovascular Center and Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Tangchun Wu
- Department of Occupational and Environmental Health and State Key Laboratory of Environmental Health for Incubating, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xu Lin
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, China
| | - Bok-Ghee Han
- Center for Genome Science, Korean National Institute of Health, Osong, Chungchungbuk-do, South Korea
| | - Toshihiro Tanaka
- Laboratory for Cardiovascular Diseases, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoon Shin Cho
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Tomohiro Katsuya
- Department of Clinical Gene Therapy, Osaka University Graduate School of Medicine, Suita, Japan
| | - Weiping Jia
- Shanghai Diabetes Institute, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Sun-Ha Jee
- Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, South Korea
| | - Yuan-Tsong Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Norihiro Kato
- National Center for Global Health and Medicine, Tokyo, Japan
| | - Jost B Jonas
- Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Department of Ophthalmology, Medical Faculty Mannheim of the Ruprecht-Karls-University of Heidelberg, Mannheim, Germany
| | - Ching-Yu Cheng
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Duke-NUS Medical School Singapore, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Xiao-Ou Shu
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jiang He
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Wei Zheng
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Tien-Yin Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Duke-NUS Medical School Singapore, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Wei Huang
- Department of Genetics, Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center and Shanghai Industrial Technology Institute, Shanghai, China
| | - Bong-Jo Kim
- Division of Structural and Functional Genomics, Center for Genome Science, Korean National Institute of Health, Osong, Chungchungbuk-do, South Korea
| | - E-Shyong Tai
- Saw Swee Hock School of Public Health, National University Health System, National University of Singapore, Singapore, Singapore.,Duke-NUS Medical School Singapore, Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Karen L Mohlke
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Xueling Sim
- Saw Swee Hock School of Public Health, National University Health System, National University of Singapore, Singapore, Singapore
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11
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Hunegnaw R, Vassylyeva M, Dubrovsky L, Pushkarsky T, Sviridov D, Anashkina AA, Üren A, Brichacek B, Vassylyev DG, Adzhubei AA, Bukrinsky M. Interaction Between HIV-1 Nef and Calnexin: From Modeling to Small Molecule Inhibitors Reversing HIV-Induced Lipid Accumulation. Arterioscler Thromb Vasc Biol 2016; 36:1758-71. [PMID: 27470515 DOI: 10.1161/atvbaha.116.307997] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/13/2016] [Indexed: 01/22/2023]
Abstract
OBJECTIVE HIV-infected patients are at an increased risk of developing atherosclerosis, in part because of downmodulation and functional impairment of ATP-binding cassette A1 (ABCA1) cholesterol transporter by the HIV-1 protein Nef. The mechanism of this effect involves Nef interacting with an ER chaperone calnexin and disrupting calnexin binding to ABCA1, leading to ABCA1 retention in ER, its degradation and resulting suppression of cholesterol efflux. However, molecular details of Nef-calnexin interaction remained unknown, limiting the translational impact of this finding. APPROACH AND RESULTS Here, we used molecular modeling and mutagenesis to characterize Nef-calnexin interaction and to identify small molecule compounds that could block it. We demonstrated that the interaction between Nef and calnexin is direct and can be reconstituted using recombinant proteins in vitro with a binding affinity of 89.1 nmol/L measured by surface plasmon resonance. The cytoplasmic tail of calnexin is essential and sufficient for interaction with Nef, and binds Nef with an affinity of 9.4 nmol/L. Replacing lysine residues in positions 4 and 7 of Nef with alanines abrogates Nef-calnexin interaction, prevents ABCA1 downregulation by Nef, and preserves cholesterol efflux from HIV-infected cells. Through virtual screening of the National Cancer Institute library of compounds, we identified a compound, 1[(7-oxo-7H-benz[de]anthracene-3-yl)amino]anthraquinone, which blocked Nef-calnexin interaction, partially restored ABCA1 activity in HIV-infected cells, and reduced foam cell formation in a culture of HIV-infected macrophages. CONCLUSION This study identifies potential targets that can be exploited to block the pathogenic effect of HIV infection on cholesterol metabolism and prevent atherosclerosis in HIV-infected subjects.
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Affiliation(s)
- Ruth Hunegnaw
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Marina Vassylyeva
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Larisa Dubrovsky
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Tatiana Pushkarsky
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Dmitri Sviridov
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Anastasia A Anashkina
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Aykut Üren
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Beda Brichacek
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Dmitry G Vassylyev
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Alexei A Adzhubei
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü).
| | - Michael Bukrinsky
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü).
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12
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Allen DG, Whitehead NP, Froehner SC. Absence of Dystrophin Disrupts Skeletal Muscle Signaling: Roles of Ca2+, Reactive Oxygen Species, and Nitric Oxide in the Development of Muscular Dystrophy. Physiol Rev 2016; 96:253-305. [PMID: 26676145 DOI: 10.1152/physrev.00007.2015] [Citation(s) in RCA: 272] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dystrophin is a long rod-shaped protein that connects the subsarcolemmal cytoskeleton to a complex of proteins in the surface membrane (dystrophin protein complex, DPC), with further connections via laminin to other extracellular matrix proteins. Initially considered a structural complex that protected the sarcolemma from mechanical damage, the DPC is now known to serve as a scaffold for numerous signaling proteins. Absence or reduced expression of dystrophin or many of the DPC components cause the muscular dystrophies, a group of inherited diseases in which repeated bouts of muscle damage lead to atrophy and fibrosis, and eventually muscle degeneration. The normal function of dystrophin is poorly defined. In its absence a complex series of changes occur with multiple muscle proteins showing reduced or increased expression or being modified in various ways. In this review, we will consider the various proteins whose expression and function is changed in muscular dystrophies, focusing on Ca(2+)-permeable channels, nitric oxide synthase, NADPH oxidase, and caveolins. Excessive Ca(2+) entry, increased membrane permeability, disordered caveolar function, and increased levels of reactive oxygen species are early changes in the disease, and the hypotheses for these phenomena will be critically considered. The aim of the review is to define the early damage pathways in muscular dystrophy which might be appropriate targets for therapy designed to minimize the muscle degeneration and slow the progression of the disease.
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Affiliation(s)
- David G Allen
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Nicholas P Whitehead
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Stanley C Froehner
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
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13
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Tamehiro N, Park MH, Hawxhurst V, Nagpal K, Adams ME, Zannis VI, Golenbock DT, Fitzgerald ML. LXR Agonism Upregulates the Macrophage ABCA1/Syntrophin Protein Complex That Can Bind ApoA-I and Stabilized ABCA1 Protein, but Complex Loss Does Not Inhibit Lipid Efflux. Biochemistry 2015; 54:6931-41. [PMID: 26506427 DOI: 10.1021/acs.biochem.5b00894] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Macrophage ABCA1 effluxes lipid and has anti-inflammatory activity. The syntrophins, which are cytoplasmic PDZ protein scaffolding factors, can bind ABCA1 and modulate its activity. However, many of the data assessing the function of the ABCA1-syntrophin interaction are based on overexpression in nonmacrophage cells. To assess endogenous complex function in macrophages, we derived immortalized macrophages from Abca1(+/+) and Abca1(-/-) mice and show their phenotype recapitulates primary macrophages. Abca1(+/+) lines express the CD11B and F4/80 macrophage markers and markedly upregulate cholesterol efflux in response to LXR nuclear hormone agonists. In contrast, immortalized Abca1(-/-) macrophages show no efflux to apoA-I. In response to LPS, Abca1(-/-) macrophages display pro-inflammatory changes, including an increased level of expression of cell surface CD14, and 11-26-fold higher levels of IL-6 and IL-12 mRNA. Given recapitulation of phenotype, we show with these lines that the ABCA1-syntrophin protein complex is upregulated by LXR agonists and can bind apoA-I. Moreover, in immortalized macrophages, combined α1/β2-syntrophin loss modulated ABCA1 cell surface levels and induced pro-inflammatory gene expression. However, loss of all three syntrophin isoforms known to bind ABCA1 did not impair lipid efflux in immortalized or primary macrophages. Thus, the ABCA1-syntrophin protein complex is not essential for ABCA1 macrophage lipid efflux but does directly interact with apoA-I and can modulate the pool of cell surface ABCA1 stabilized by apoA-I.
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Affiliation(s)
- Norimasa Tamehiro
- Lipid Metabolism Unit, Massachusetts General Hospital (MGH), Center for Computational & Integrative Biology (CCIB), Richard B. Simches Research Center , 185 Cambridge Street, 7th Floor #7150, Boston, Massachusetts 02114, United States
| | - Min Hi Park
- Lipid Metabolism Unit, Massachusetts General Hospital (MGH), Center for Computational & Integrative Biology (CCIB), Richard B. Simches Research Center , 185 Cambridge Street, 7th Floor #7150, Boston, Massachusetts 02114, United States
| | - Victoria Hawxhurst
- Lipid Metabolism Unit, Massachusetts General Hospital (MGH), Center for Computational & Integrative Biology (CCIB), Richard B. Simches Research Center , 185 Cambridge Street, 7th Floor #7150, Boston, Massachusetts 02114, United States
| | - Kamalpreet Nagpal
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States
| | - Marv E Adams
- University of Washington , 1705 Northeast Pacific Street, H-418 HSB Campus Box 357290, Seattle, Washington 98195, United States
| | - Vassilis I Zannis
- Whitaker Cardiovascular Institute, Boston University School of Medicine , 700 Albany Street, W509, Boston, Massachusetts 02118, United States
| | - Douglas T Golenbock
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States
| | - Michael L Fitzgerald
- Lipid Metabolism Unit, Massachusetts General Hospital (MGH), Center for Computational & Integrative Biology (CCIB), Richard B. Simches Research Center , 185 Cambridge Street, 7th Floor #7150, Boston, Massachusetts 02114, United States
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14
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Cellular Cholesterol Accumulation Facilitates Ubiquitination and Lysosomal Degradation of Cell Surface–Resident ABCA1. Arterioscler Thromb Vasc Biol 2015; 35:1347-56. [DOI: 10.1161/atvbaha.114.305182] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 03/24/2015] [Indexed: 11/16/2022]
Abstract
Objective—
By excreting cellular cholesterol to apolipoprotein A-I, ATP-binding cassette transporter A1 (ABCA1) mediates the biogenesis of high-density lipoprotein in hepatocytes and prevents foam cell formation from macrophages. We recently showed that cell surface–resident ABCA1 (csABCA1) undergoes ubiquitination and later lysosomal degradation through the endosomal sorting complex required for transport system. Herein, we investigated the relevance of this degradation pathway to the turnover of csABCA1 in hypercholesterolemia.
Approach and Results—
Immunoprecipitation and cell surface-biotinylation studies with HepG2 cells and mouse peritoneal macrophages showed that the ubiquitination level and degradation of csABCA1 were facilitated by treatment with a liver X receptor (LXR) agonist and acetylated low-density lipoprotein. The effects of an LXR agonist and acetylated low-density lipoprotein on the degradation of csABCA1 were repressed completely by treatment with bafilomycin, an inhibitor of lysosomal degradation, and by depletion of tumor susceptibility gene 101, a major component of endosomal sorting complex required for transport-I. RNAi analysis indicated that LXRβ inhibited the accelerated lysosomal degradation of csABCA1 by the LXR agonist, regardless of its transcriptional activity. Cell surface coimmunoprecipitation with COS1 cells expressing extracellularly hemagglutinin-tagged ABCA1 showed that LXRβ interacted with csABCA1 and inhibited the ubiquitination of csABCA1. Immunoprecipitates with anti-ABCA1 antibodies from the liver plasma membranes showed less LXRβ and a higher ubiquitination level of ABCA1 in high-fat diet–fed mice than in normal chow-fed mice.
Conclusions—
Under conditions of high cellular cholesterol content, csABCA1 became susceptible to ubiquitination by dissociation of LXRβ from csABCA1, which facilitated the lysosomal degradation of csABCA1 through the endosomal sorting complex required for transport system.
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15
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Olsson M, Tintle L, Kierczak M, Perloski M, Tonomura N, Lundquist A, Murén E, Fels M, Tengvall K, Pielberg G, Dufaure de Citres C, Dorso L, Abadie J, Hanson J, Thomas A, Leegwater P, Hedhammar Å, Lindblad-Toh K, Meadows JRS. Thorough investigation of a canine autoinflammatory disease (AID) confirms one main risk locus and suggests a modifier locus for amyloidosis. PLoS One 2013; 8:e75242. [PMID: 24130694 PMCID: PMC3793984 DOI: 10.1371/journal.pone.0075242] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 08/13/2013] [Indexed: 12/04/2022] Open
Abstract
Autoinflammatory disease (AID) manifests from the dysregulation of the innate immune system and is characterised by systemic and persistent inflammation. Clinical heterogeneity leads to patients presenting with one or a spectrum of phenotypic signs, leading to difficult diagnoses in the absence of a clear genetic cause. We used separate genome-wide SNP analyses to investigate five signs of AID (recurrent fever, arthritis, breed specific secondary dermatitis, otitis and systemic reactive amyloidosis) in a canine comparative model, the pure bred Chinese Shar-Pei. Analysis of 255 DNA samples revealed a shared locus on chromosome 13 spanning two peaks of association. A three-marker haplotype based on the most significant SNP (p<2.6×10−8) from each analysis showed that one haplotypic pair (H13-11) was present in the majority of AID individuals, implicating this as a shared risk factor for all phenotypes. We also noted that a genetic signature (FST) distinguishing the phenotypic extremes of the breed specific Chinese Shar-Pei thick and wrinkled skin, flanked the chromosome 13 AID locus; suggesting that breed development and differentiation has played a parallel role in the genetics of breed fitness. Intriguingly, a potential modifier locus for amyloidosis was revealed on chromosome 14, and an investigation of candidate genes from both this and the chromosome 13 regions revealed significant (p<0.05) renal differential expression in four genes previously implicated in kidney or immune health (AOAH, ELMO1, HAS2 and IL6). These results illustrate that phenotypic heterogeneity need not be a reflection of genetic heterogeneity, and that genetic modifiers of disease could be masked if syndromes were not first considered as individual clinical signs and then as a sum of their component parts.
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Affiliation(s)
- Mia Olsson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- * E-mail: (MO); (KL-T); (JRSM)
| | - Linda Tintle
- Wurtsboro Veterinary Clinic, Wurtsboro, New York, United States of America
| | - Marcin Kierczak
- Computational Genetics Section, Department of Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Michele Perloski
- Broad Institute of Harvard and Massachusetts Institute of Technology (MIT), Cambridge, MA, United States of America
| | - Noriko Tonomura
- Broad Institute of Harvard and Massachusetts Institute of Technology (MIT), Cambridge, MA, United States of America
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, United States of America
| | - Andrew Lundquist
- Broad Institute of Harvard and Massachusetts Institute of Technology (MIT), Cambridge, MA, United States of America
| | - Eva Murén
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Max Fels
- Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Katarina Tengvall
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Gerli Pielberg
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | | | - Laetitia Dorso
- LUNAM University, Oniris, AMaROC Unit, Nantes, F-44307, France
| | - Jérôme Abadie
- LUNAM University, Oniris, AMaROC Unit, Nantes, F-44307, France
| | - Jeanette Hanson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Anne Thomas
- ANTAGENE Animal Genetics Laboratory, La Tour de Salvagny (69 Lyon), France
| | - Peter Leegwater
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands
| | - Åke Hedhammar
- Department of Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Kerstin Lindblad-Toh
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Broad Institute of Harvard and Massachusetts Institute of Technology (MIT), Cambridge, MA, United States of America
- * E-mail: (MO); (KL-T); (JRSM)
| | - Jennifer R. S. Meadows
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- * E-mail: (MO); (KL-T); (JRSM)
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16
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Khor CC, Miyake M, Chen LJ, Shi Y, Barathi VA, Qiao F, Nakata I, Yamashiro K, Zhou X, Tam POS, Cheng CY, Tai ES, Vithana EN, Aung T, Teo YY, Wong TY, Moriyama M, Ohno-Matsui K, Mochizuki M, Matsuda F, Yong RYY, Yap EPH, Yang Z, Pang CP, Saw SM, Yoshimura N. Genome-wide association study identifies ZFHX1B as a susceptibility locus for severe myopia. Hum Mol Genet 2013; 22:5288-94. [PMID: 23933737 DOI: 10.1093/hmg/ddt385] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Severe myopia (defined as spherical equivalent < -6.0 D) is a predominant problem in Asian countries, resulting in substantial morbidity. We performed a meta-analysis of four genome-wide association studies (GWAS), all of East Asian descent totaling 1603 cases and 3427 controls. Two single nucleotide polymorphisms (SNPs) (rs13382811 from ZFHX1B [encoding for ZEB2] and rs6469937 from SNTB1) showed highly suggestive evidence of association with disease (P < 1 × 10(-7)) and were brought forward for replication analysis in a further 1241 severe myopia cases and 3559 controls from a further three independent sample collections. Significant evidence of replication was observed, and both SNP markers surpassed the formal threshold for genome-wide significance upon meta-analysis of both discovery and replication stages (P = 5.79 × 10(-10), per-allele odds ratio (OR) = 1.26 for rs13382811 and P = 2.01 × 10(-9), per-allele OR = 0.79 for rs6469937). The observation at SNTB1 is confirmatory of a very recent GWAS on severe myopia. Both genes were expressed in the human retina, sclera, as well as the retinal pigmented epithelium. In an experimental mouse model for myopia, we observed significant alterations to gene and protein expression in the retina and sclera of the unilateral induced myopic eyes for Zfhx1b and Sntb1. These new data advance our understanding of the molecular pathogenesis of severe myopia.
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Affiliation(s)
- Chiea Chuen Khor
- Division of Human Genetics, Genome Institute of Singapore, Singapore, Singapore
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17
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Neumeier M, Krautbauer S, Schmidhofer S, Hader Y, Eisinger K, Eggenhofer E, Froehner SC, Adams ME, Mages W, Buechler C. Adiponectin receptor 1 C-terminus interacts with PDZ-domain proteins such as syntrophins. Exp Mol Pathol 2013; 95:180-6. [PMID: 23860432 DOI: 10.1016/j.yexmp.2013.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 07/02/2013] [Indexed: 01/22/2023]
Abstract
Adiponectin receptor 1 (AdipoR1) is one of the two signaling receptors of adiponectin with multiple beneficial effects in metabolic diseases. AdipoR1 C-terminal peptide is concordant with the consensus sequence of class I PSD-95, disc large, ZO-1 (PDZ) proteins, and screening of a liver yeast two hybrid library identified binding to β2-syntrophin (SNTB2). Hybridization of a PDZ-domain array with AdipoR1 C-terminal peptide shows association with PDZ-domains of further proteins including β1- and α-syntrophin (SNTA). Interaction of PDZ proteins and C-terminal peptides requires a free carboxy terminus next to the PDZ-binding region and is blocked by carboxy terminal added tags. N-terminal tagged AdipoR1 is more highly expressed than C-terminal tagged receptor suggesting that the free carboxy terminus may form a complex with PDZ proteins to regulate cellular AdipoR1 levels. The C- and N-terminal tagged AdipoR1 proteins are mainly localized in the cytoplasma. N-terminal but not C-terminal tagged AdipoR1 colocalizes with syntrophins in adiponectin incubated Huh7 cells. Adiponectin induced hepatic phosphorylation of AMPK and p38 MAPK which are targets of AdipoR1 is, however, not blocked in SNTA and SNTB2 deficient mice. Further, AdipoR1 protein is similarly abundant in the liver of knock-out and wild type mice when kept on a standard chow or a high fat diet. In summary these data suggest that AdipoR1 protein levels are regulated by so far uncharacterized class I PDZ proteins which are distinct from SNTA and SNTB2.
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Affiliation(s)
- Markus Neumeier
- Department of Internal Medicine I, University of Regensburg, Regensburg, Germany
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18
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Lv YC, Yin K, Fu YC, Zhang DW, Chen WJ, Tang CK. Posttranscriptional Regulation ofATP-Binding Cassette Transporter A1in Lipid Metabolism. DNA Cell Biol 2013; 32:348-58. [DOI: 10.1089/dna.2012.1940] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- Yun-cheng Lv
- Key Laboratory for Atherosclerology of Hunan Province, Institute of Cardiovascular Research, Life Science Research Center, University of South China, Hengyang, China
- Laboratory of Clinical Anatomy, University of South China, Hengyang, China
| | - Kai Yin
- Key Laboratory for Atherosclerology of Hunan Province, Institute of Cardiovascular Research, Life Science Research Center, University of South China, Hengyang, China
| | - Yu-chang Fu
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Da-wei Zhang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Canada
| | - Wu-jun Chen
- Key Laboratory for Atherosclerology of Hunan Province, Institute of Cardiovascular Research, Life Science Research Center, University of South China, Hengyang, China
| | - Chao-ke Tang
- Key Laboratory for Atherosclerology of Hunan Province, Institute of Cardiovascular Research, Life Science Research Center, University of South China, Hengyang, China
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19
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Bhat HF, Adams ME, Khanday FA. Syntrophin proteins as Santa Claus: role(s) in cell signal transduction. Cell Mol Life Sci 2013; 70:2533-54. [PMID: 23263165 PMCID: PMC11113789 DOI: 10.1007/s00018-012-1233-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 11/21/2012] [Accepted: 12/03/2012] [Indexed: 11/30/2022]
Abstract
Syntrophins are a family of cytoplasmic membrane-associated adaptor proteins, characterized by the presence of a unique domain organization comprised of a C-terminal syntrophin unique (SU) domain and an N-terminal pleckstrin homology (PH) domain that is split by insertion of a PDZ domain. Syntrophins have been recognized as an important component of many signaling events, and they seem to function more like the cell's own personal 'Santa Claus' that serves to 'gift' various signaling complexes with precise proteins that they 'wish for', and at the same time care enough for the spatial, temporal control of these signaling events, maintaining overall smooth functioning and general happiness of the cell. Syntrophins not only associate various ion channels and signaling proteins to the dystrophin-associated protein complex (DAPC), via a direct interaction with dystrophin protein but also serve as a link between the extracellular matrix and the intracellular downstream targets and cell cytoskeleton by interacting with F-actin. They play an important role in regulating the postsynaptic signal transduction, sarcolemmal localization of nNOS, EphA4 signaling at the neuromuscular junction, and G-protein mediated signaling. In our previous work, we reported a differential expression pattern of alpha-1-syntrophin (SNTA1) protein in esophageal and breast carcinomas. Implicated in several other pathologies, like cardiac dys-functioning, muscular dystrophies, diabetes, etc., these proteins provide a lot of scope for further studies. The present review focuses on the role of syntrophins in membrane targeting and regulation of cellular proteins, while highlighting their relevance in possible development and/or progression of pathologies including cancer which we have recently demonstrated.
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Affiliation(s)
- Hina F Bhat
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India.
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20
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Shi Y, Gong B, Chen L, Zuo X, Liu X, Tam POS, Zhou X, Zhao P, Lu F, Qu J, Sun L, Zhao F, Chen H, Zhang Y, Zhang D, Lin Y, Lin H, Ma S, Cheng J, Yang J, Huang L, Zhang M, Zhang X, Pang CP, Yang Z. A genome-wide meta-analysis identifies two novel loci associated with high myopia in the Han Chinese population. Hum Mol Genet 2013; 22:2325-33. [PMID: 23406873 DOI: 10.1093/hmg/ddt066] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
High myopia, highly prevalent in the Chinese population, is a leading cause of visual impairment worldwide. Genetic factors play a critical role in the development of this visual disorder. Genome-wide association studies in recent years have revealed several chromosomal regions that contribute to its progression. To identify additional genetic variants for high myopia susceptibility, we used a genome-wide meta-analysis to examine the associations between the disease and 286 031 single-nucleotide polymorphisms (SNPs) in a combined cohort of 665 cases and 960 controls. The most significant SNPs (n = 61) were genotyped in a replication cohort (850 cases and 1197 controls), and 14 SNPs were further tested through genotyping in two additional validation cohorts (combined 1278 cases and 2486 controls). As a result of this analysis, four SNPs reached genome-wide significance (P < 2.0 × 10(-7)). The most significantly associated SNP, rs2730260 [overall P = 8.95 × 10(-14); odds ratio (95% CI) =1.33 (1.23-1.44)], is located in the VIPR2 gene, which is located in the MYP4 locus. The other three SNPs (rs7839488, rs4395927 and rs4455882) in the same linkage disequilibrium block are located in the SNTB1 gene, with -P values ranging from 1.13 × 10(-8) to 2.13 × 10(-11). The VIPR2 and SNTB1 genes are expressed in the retina and the retinal pigment epithelium and have been previously reported to have potential functions for the pathogenesis of myopia. Our results suggest that variants of the VIPR2 and SNTB1 genes increase susceptibility to high myopia in Han Chinese.
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Affiliation(s)
- Yi Shi
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People’s Hospital, Chengdu, Sichuan 610072, China
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21
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Nagao K, Maeda M, Mañucat NB, Ueda K. Cyclosporine A and PSC833 inhibit ABCA1 function via direct binding. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:398-406. [PMID: 23153588 DOI: 10.1016/j.bbalip.2012.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/06/2012] [Accepted: 11/05/2012] [Indexed: 10/27/2022]
Abstract
ATP-binding cassette protein A1 (ABCA1) plays a key role in generating high-density lipoprotein (HDL). However, the detailed mechanism of HDL formation remains unclear; in order to reveal it, chemicals that specifically block each step of HDL formation would be useful. Cyclosporine A inhibits ABCA1-mediated cholesterol efflux, but it is not clear whether this is mediated via inhibition of calcineurin. We analyzed the effects of cyclosporine A and related compounds on ABCA1 function in BHK/ABCA1 cells. Cyclosporine A, FK506, and pimecrolimus inhibited ABCA1-mediated cholesterol efflux in a concentration-dependent manner, with IC(50) of 7.6, 13.6, and 7.0μM, respectively. An mTOR inhibitor, rapamycin also inhibited ABCA1, with IC(50) of 18.8μM. The primary targets for these drugs were inhibited at much lower concentrations in BHK/ABCA1 cells, suggesting that they were not involved. Binding of [(3)H] cyclosporine A to purified ABCA1 could be clearly detected. Furthermore, a non-immunosuppressive cyclosporine, PSC833, inhibited ABCA1-mediated cholesterol efflux with IC(50) of 1.9μM, and efficiently competed with [(3)H] cyclosporine A binding to ABCA1. These results indicate that cyclosporine A and PSC833 inhibit ABCA1 via direct binding, and that the ABCA1 inhibitor PSC833 is an excellent candidate for further investigations of the detailed mechanisms underlying formation of HDL.
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Affiliation(s)
- Kohjiro Nagao
- Institute for integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto 606-8502, Japan
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22
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Sanhueza J, Valenzuela R, Valenzuela A. El metabolismo del colesterol: cada vez más complejo. GRASAS Y ACEITES 2012. [DOI: 10.3989/gya.035512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Mizuno T, Hayashi H, Naoi S, Sugiyama Y. Ubiquitination is associated with lysosomal degradation of cell surface-resident ATP-binding cassette transporter A1 (ABCA1) through the endosomal sorting complex required for transport (ESCRT) pathway. Hepatology 2011; 54:631-43. [PMID: 21520210 DOI: 10.1002/hep.24387] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 04/14/2011] [Indexed: 12/31/2022]
Abstract
UNLABELLED ATP-binding cassette transporter A1 (ABCA1) plays an essential role in the biogenesis of high-density lipoprotein in liver and in the prevention of foam cell formation in macrophages by mediating the efflux of cellular cholesterol and phospholipids to apolipoprotein A-I (apoA-I). Our current study investigated the mechanism of degradation of cell surface-resident ABCA1, focusing on ubiquitination. A coimmunoprecipitation study indicated the presence of ubiquitinated ABCA1 in the plasma membrane of the human hepatoma cell line, HuH-7, of cells from mouse liver, and of macrophages differentiated from the human acute monocytic leukemia cell line, THP-1 (THP-1 macrophages). In HuH-7 cells, degradation of cell surface-resident ABCA1 was inhibited by the overexpression of a dominant-negative form of ubiquitin. Moreover, the disruption of the endosomal sorting complex required for transport (ESCRT) pathway, a dominant mechanism for ubiquitination-mediated lysosomal degradation, by the knockdown of hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), significantly delayed the degradation of cell surface-resident ABCA1. This was accompanied by an increase in ABCA1 expression as well as in apoA-I-mediated [3H]-cholesterol efflux function. The effect of HRS knockdown was also observed after calpain inhibitor treatment, which is reported to retard ABCA1 degradation. The induction of ABCA1 by HRS knockdown was confirmed in THP-1 macrophages. CONCLUSION Together with the fact that lysosomal inhibitor treatments increased ABCA1 expression in HuH-7 and THP-1 macrophages, these results suggest that ubiquitination mediates the lysosomal degradation of cell surface-resident ABCA1 through the ESCRT pathway, and thereby controls the expression and cholesterol efflux function of ABCA1. This mechanism seems to mediate ABCA1 degradation independently of the calpain-involving pathway. The modulation of ABCA1 ubiquitination could thus be a potential new therapeutic target for antiatherogenic drugs.
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Affiliation(s)
- Tadahaya Mizuno
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
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24
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Nagao K, Tomioka M, Ueda K. Function and regulation of ABCA1 - membrane meso-domain organization and reorganization. FEBS J 2011; 278:3190-203. [DOI: 10.1111/j.1742-4658.2011.08170.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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25
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Hozoji-Inada M, Munehira Y, Nagao K, Kioka N, Ueda K. Liver X receptor beta (LXRbeta) interacts directly with ATP-binding cassette A1 (ABCA1) to promote high density lipoprotein formation during acute cholesterol accumulation. J Biol Chem 2011; 286:20117-24. [PMID: 21507939 DOI: 10.1074/jbc.m111.235846] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cells have evolved multiple mechanisms for maintaining cholesterol homeostasis, and, among these, ATP-binding cassette protein A1 (ABCA1)-mediated cholesterol efflux is highly regulated at the transcriptional level through the activity of the nuclear receptor liver X receptor (LXR). Here, we show that in addition to its well defined role in transcription, LXRβ directly binds to the C-terminal region ((2247)LTSFL(2251)) of ABCA1 to mediate its post-translational regulation. In the absence of cholesterol accumulation in the macrophage-like cell line THP-1, the ABCA1-LXRβ complex stably localizes to the plasma membrane, but apolipoprotein A-I (apoA-I) binding or cholesterol efflux does not occur. Exogenously added LXR ligands, which mimic cholesterol accumulation, cause LXRβ to dissociate from ABCA1, thus freeing ABCA1 for apoA-I binding and subsequent cholesterol efflux. Photoaffinity labeling experiments with 8-azido-[α-(32)P]ATP showed that the interaction of LXRβ with ABCA1 inhibits ATP binding by ABCA1. This is the first study to show that a protein-protein interaction with the endogenous protein suppresses the function of ABC proteins by inhibiting ATP binding. LXRβ can cause a post-translational response by binding directly to ABCA1, as well as a transcriptional response, to maintain cholesterol homeostasis.
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Affiliation(s)
- Masako Hozoji-Inada
- Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan
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26
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Abstract
Human MDR1, a multi-drug transporter gene, was isolated as the first of the eukaryote ATP Binding Cassette (ABC) proteins from a multidrug-resistant carcinoma cell line in 1986. To date, over 25 years, many ABC proteins have been found to play important physiological roles by transporting hydrophobic compounds. Defects in their functions cause various diseases, indicating that endogenous hydrophobic compounds, as well as water-soluble compounds, are properly transported by transmembrane proteins. MDR1 transports a large number of structurally unrelated drugs and is involved in their pharmacokinetics, and thus is a key factor in drug interaction. ABCA1, an ABC protein, eliminates excess cholesterol in peripheral cells by generating HDL. Because ABCA1 is a key molecule in cholesterol homeostasis, its function and expression are highly regulated. Eukaryote ABC proteins function on the body surface facing the outside and in organ pathways to adapt to the extracellular environment and protect the body to maintain optimal health.
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27
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De Arcangelis V, Serra F, Cogoni C, Vivarelli E, Monaco L, Naro F. β1-syntrophin modulation by miR-222 in mdx mice. PLoS One 2010; 5:e12098. [PMID: 20856896 PMCID: PMC2938373 DOI: 10.1371/journal.pone.0012098] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 07/18/2010] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND In mdx mice, the absence of dystrophin leads to the deficiency of other components of the dystrophin-glycoprotein complex (DAPC), making skeletal muscle fibers more susceptible to necrosis. The mechanisms involved in the disappearance of the DAPC are not completely understood. The muscles of mdx mice express normal amounts of mRNA for the DAPC components, thus suggesting post-transcriptional regulation. METHODOLOGY/PRINCIPAL FINDINGS We investigated the hypothesis that DAPC reduction could be associated with the microRNA system. Among the possible microRNAs (miRs) found to be upregulated in the skeletal muscle tissue of mdx compared to wt mice, we demonstrated that miR-222 specifically binds to the 3'-UTR of β1-syntrophin and participates in the downregulation of β1-syntrophin. In addition, we documented an altered regulation of the 3'-UTR of β1-syntrophin in muscle tissue from dystrophic mice. CONCLUSION/SIGNIFICANCE These results show the importance of the microRNA system in the regulation of DAPC components in dystrophic muscle, and suggest a potential role of miRs in the pathophysiology of dystrophy.
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Affiliation(s)
| | - Filippo Serra
- Department of Histology and Medical Embryology, University Sapienza, Rome, Italy
| | - Carlo Cogoni
- Department of Cellular Biotechnology and Ematology, University Sapienza, Rome, Italy
| | - Elisabetta Vivarelli
- Department of Histology and Medical Embryology, University Sapienza, Rome, Italy
| | - Lucia Monaco
- Department of Physiology and Pharmacology, University Sapienza, Rome, Italy
| | - Fabio Naro
- Department of Histology and Medical Embryology, University Sapienza, Rome, Italy
- IIM, Pavia, Italy
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28
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Nagao K, Kimura Y, Mastuo M, Ueda K. Lipid outward translocation by ABC proteins. FEBS Lett 2010; 584:2717-23. [PMID: 20412807 DOI: 10.1016/j.febslet.2010.04.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 04/13/2010] [Accepted: 04/14/2010] [Indexed: 11/18/2022]
Abstract
In humans, about 50 ABC proteins play physiologically important roles. Many ABC proteins are involved in lipid outward translocation and lipid homeostasis in the body, and defects in their functions cause various diseases. However, the precise mechanisms of substrate transport remain unclear. In bacteria, several ABC proteins are involved in the transport of lipoproteins and lipopolysaccharides from the inner to outer membrane, and their functioning is a prerequisite for survival. Their functions can be divided into "flip-flop" and "projection". In this review, human ABC proteins are compared to bacterial proteins to elucidate their mechanisms.
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Affiliation(s)
- Kohjiro Nagao
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, Japan
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29
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Okuhira K, Fitzgerald ML, Tamehiro N, Ohoka N, Suzuki K, Sawada JI, Naito M, Nishimaki-Mogami T. Binding of PDZ-RhoGEF to ATP-binding cassette transporter A1 (ABCA1) induces cholesterol efflux through RhoA activation and prevention of transporter degradation. J Biol Chem 2010; 285:16369-77. [PMID: 20348106 DOI: 10.1074/jbc.m109.061424] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP-binding cassette transporter A1 (ABCA1)-mediated lipid efflux to apolipoprotein A1 (apoA-I) initiates the biogenesis of high density lipoprotein. Here we show that the Rho guanine nucleotide exchange factors PDZ-RhoGEF and LARG bind to the C terminus of ABCA1 by a PDZ-PDZ interaction and prevent ABCA1 protein degradation by activating RhoA. ABCA1 is a protein with a short half-life, and apoA-I stabilizes ABCA1 protein; however, depletion of PDZ-RhoGEF/LARG by RNA interference suppressed the apoA-I stabilization of ABCA1 protein in human primary fibroblasts. Exogenous PDZ-RhoGEF expression activated RhoA and increased ABCA1 protein levels and cholesterol efflux activity. Likewise, forced expression of a constitutively active RhoA mutant significantly increased ABCA1 protein levels, whereas a dominant negative RhoA mutant decreased them. The constitutively active RhoA retarded ABCA1 degradation, thus accounting for its ability to increase ABCA1 protein. Moreover, stimulation with apoA-I transiently activated RhoA, and the pharmacological inhibition of RhoA or the dominant negative RhoA blocked the ability of apoA-I to stabilize ABCA1. Finally, depletion of RhoA or RhoGEFs/RhoA reduces the cholesterol efflux when transcriptional regulation via PPARgamma is eliminated. Taken together, our results have identified a novel physical and functional interaction between ABCA1 and PDZ-RhoGEF/LARG, which activates RhoA, resulting in ABCA1 stabilization and cholesterol efflux activity.
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Affiliation(s)
- Keiichiro Okuhira
- National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8511, Japan
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Fitzgerald ML, Mujawar Z, Tamehiro N. ABC transporters, atherosclerosis and inflammation. Atherosclerosis 2010; 211:361-70. [PMID: 20138281 DOI: 10.1016/j.atherosclerosis.2010.01.011] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 01/06/2010] [Accepted: 01/07/2010] [Indexed: 10/19/2022]
Abstract
Atherosclerosis, driven by inflamed lipid-laden lesions, can occlude the coronary arteries and lead to myocardial infarction. This chronic disease is a major and expensive health burden. However, the body is able to mobilize and excrete cholesterol and other lipids, thus preventing atherosclerosis by a process termed reverse cholesterol transport (RCT). Insight into the mechanism of RCT has been gained by the study of two rare syndromes caused by the mutation of ABC transporter loci. In Tangier disease, loss of ABCA1 prevents cells from exporting cholesterol and phospholipid, thus resulting in the build-up of cholesterol in the peripheral tissues and a loss of circulating HDL. Consistent with HDL being an athero-protective particle, Tangier patients are more prone to develop atherosclerosis. Likewise, sitosterolemia is another inherited syndrome associated with premature atherosclerosis. Here mutations in either the ABCG5 or G8 loci, prevents hepatocytes and enterocytes from excreting cholesterol and plant sterols, including sitosterol, into the bile and intestinal lumen. Thus, ABCG5 and G8, which from a heterodimer, constitute a transporter that excretes cholesterol and dietary sterols back into the gut, while ABCA1 functions to export excess cell cholesterol and phospholipid during the biogenesis of HDL. Interestingly, a third protein, ABCG1, that has been shown to have anti-atherosclerotic activity in mice, may also act to transfer cholesterol to mature HDL particles. Here we review the relationship between the lipid transport activities of these proteins and their anti-atherosclerotic effect, particularly how they may reduce inflammatory signaling pathways. Of particular interest are recent reports that indicate both ABCA1 and ABCG1 modulate cell surface cholesterol levels and inhibit its partitioning into lipid rafts. Given lipid rafts may provide platforms for innate immune receptors to respond to inflammatory signals, it follows that loss of ABCA1 and ABCG1 by increasing raft content will increase signaling through these receptors, as has been experimentally demonstrated. Moreover, additional reports indicate ABCA1, and possibly SR-BI, another HDL receptor, may directly act as anti-inflammatory receptors independent of their lipid transport activities. Finally, we give an update on the progress and pitfalls of therapeutic approaches that seek to stimulate the flux of lipids through the RCT pathway.
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Affiliation(s)
- Michael L Fitzgerald
- Lipid Metabolism Unit, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA.
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32
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Tamehiro N, Mujawar Z, Zhou S, Zhuang DZ, Hornemann T, von Eckardstein A, Fitzgerald ML. Cell polarity factor Par3 binds SPTLC1 and modulates monocyte serine palmitoyltransferase activity and chemotaxis. J Biol Chem 2009; 284:24881-90. [PMID: 19592499 DOI: 10.1074/jbc.m109.014365] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Elevated sphingolipids have been associated with increased cardiovascular disease. Conversely, atherosclerosis is reduced in mice by blocking de novo synthesis of sphingolipids catalyzed by serine palmitoyltransferase (SPT). The SPT enzyme is composed of the SPTLC1 and -2 subunits, and here we describe a novel protein-protein interaction between SPTLC1 and the PDZ protein Par3 (partitioning defective protein 3). Mammalian SPTLC1 orthologs have a highly conserved C terminus that conforms to a type II PDZ protein interaction motif, and by screening PDZ domain protein arrays with an SPTLC1 C-terminal peptide, we found it bound the third PDZ domain of Par3. Overlay and immunoprecipitation assays confirmed this interaction and indicate Par3 is able to associate with the SPTLC1/2 holoenzyme by binding the C-terminal SPTLC1 PDZ motif. The physiologic existence of the SPTLC1/2-Par3 complex was detected in mouse liver and macrophages, and short interfering RNA inhibition of Par3 in human THP-1 monocytes significantly reduced SPT activity and de novo ceramide synthesis by nearly 40%. Given monocyte recruitment into inflamed vessels is thought to promote atherosclerosis, and because Par3 and sphingolipids have been associated with polarized cell migration, we tested whether the ability of THP-1 monocytes to migrate toward MCP-1 (monocyte chemoattractant protein 1) depended upon Par3 and SPTLC1 expression. Knockdown of Par3 significantly reduced MCP1-induced chemotaxis of THP-1 monocytes, as did knockdown of SPTLC1, and this Par3 effect depended upon SPT activity and was blunted by ceramide treatment. In conclusion, protein arrays were used to identify a novel SPTLC1-Par3 interaction that associates with increased monocyte serine palmitoyltransferase activity and chemotaxis toward inflammatory signals.
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Affiliation(s)
- Norimasa Tamehiro
- Lipid Metabolism Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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33
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Rashid S, Marcil M, Ruel I, Genest J. Identification of a novel human cellular HDL biosynthesis defect. Eur Heart J 2009; 30:2204-12. [DOI: 10.1093/eurheartj/ehp250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wei J, Yerokun T, Leipelt M, Haynes CA, Radhakrishna H, Momin A, Kelly S, Park H, Wang E, Carton JM, Uhlinger DJ, Merrill AH. Serine palmitoyltransferase subunit 1 is present in the endoplasmic reticulum, nucleus and focal adhesions, and functions in cell morphology. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:746-56. [PMID: 19362163 DOI: 10.1016/j.bbalip.2009.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 03/27/2009] [Accepted: 03/31/2009] [Indexed: 10/20/2022]
Abstract
Serine palmitoyltransferase (SPT) has been localized to the endoplasmic reticulum (ER) by subcellular fractionation and enzymatic assays, and fluorescence microscopy of epitope-tagged SPT; however, our studies have suggested that SPT subunit 1 might be present also in focal adhesions and the nucleus. These additional locations have been confirmed by confocal microscopy using HEK293 and HeLa cells, and for focal adhesions by the demonstration that SPT1 co-immunoprecipitates with vinculin, a focal adhesion marker protein. The focal adhesion localization of SPT1 is associated with cell morphology, and possibly cell migration, because it is seen in most cells before they reach confluence but disappears when they become confluent, and is restored by a standard scratch-wound healing assay. Conversely, elimination of SPT1 using SPTLC1 siRNA causes cell rounding. Thus, in addition to its "traditional" localization in the ER for de novo sphingolipid biosynthesis, SPT1 is present in other cellular compartments, including focal adhesions where it is associated with cell morphology.
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Affiliation(s)
- Jia Wei
- Petit Institute for Bioengineering and Bioscience, Atlanta, GA 30332, USA
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35
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Azuma Y, Takada M, Maeda M, Kioka N, Ueda K. The COP9 signalosome controls ubiquitinylation of ABCA1. Biochem Biophys Res Commun 2009; 382:145-8. [DOI: 10.1016/j.bbrc.2009.02.161] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 02/27/2009] [Indexed: 11/25/2022]
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36
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Linder MD, Mäyränpää MI, Peränen J, Pietilä TE, Pietiäinen VM, Uronen RL, Olkkonen VM, Kovanen PT, Ikonen E. Rab8 regulates ABCA1 cell surface expression and facilitates cholesterol efflux in primary human macrophages. Arterioscler Thromb Vasc Biol 2009; 29:883-8. [PMID: 19304576 DOI: 10.1161/atvbaha.108.179481] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE ATP-binding cassette transporter A1 (ABCA1) is thought to lipidate apolipoprotein A-I (apoA-I) at the plasma membrane, with endosomal cholesterol contributing as substrate. The mechanisms of ABCA1 surface delivery are not well understood. We have shown that Rab8 regulates endosomal cholesterol removal to apoA-I in human fibroblasts. Here, we investigated whether Rab8 plays a role in ABCA1 plasma membrane expression and cholesterol removal in primary human macrophages. METHODS AND RESULTS We found that Rab8 was abundantly expressed in human atherosclerotic lesional macrophages and upregulated on lipid loading of macrophages in vitro. Adenoviral overexpression of Rab8 increased ABCA1 protein levels and reduced cholesterol deposition in macrophage foam cells incubated with apoA-I. Depletion of Rab8 decreased the fraction of ABCA1 at the plasma membrane and inhibited the efflux of lipoprotein-derived endosomal cholesterol to apoA-I. In Rab8-depleted cells, ABCA1-GFP localized in beta1 integrin and transferrin receptor containing recycling organelles. CONCLUSIONS Rab8 reduces foam cell formation by facilitating ABCA1 surface expression and stimulating endosomal cholesterol efflux to apoA-I in primary human macrophages.
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Affiliation(s)
- Matts D Linder
- Institute of Biomedicine/Anatomy, Haartmaninkatu 8, 00014 University of Helsinki, Finland
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Lu R, Arakawa R, Ito-Osumi C, Iwamoto N, Yokoyama S. ApoA-I facilitates ABCA1 recycle/accumulation to cell surface by inhibiting its intracellular degradation and increases HDL generation. Arterioscler Thromb Vasc Biol 2008; 28:1820-4. [PMID: 18617649 DOI: 10.1161/atvbaha.108.169482] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Calpain-mediated proteolysis is one of the major regulatory factors for activity of ATP-binding cassette transporter (ABC) A1. Helical apolipoproteins protect ABCA1 against this degradation and increase generation of HDL. We investigated the mechanism for this reaction focusing on roles of endocytotic internalization of ABCA1. METHODS AND RESULTS Surface ABCA1 was labeled with biotin and traced for its internalization and degradation. ABCA1 in the cell surface was internalized within 10 minutes regardless of the presence of apoA-I. ABCA1 was intracellularly degraded and was protected against this only when exposed to extracellular apoA-I before its endocytosis. Consequently, recycle of ABCA1 to the surface was enhanced, and surface ABCA1 was increased by apoA-I. Direct inhibition of ABCA1 endocytosis led to decrease of its degradation and increase of surface ABCA1. Generation of HDL increased in parallel with surface ABCA1. CONCLUSIONS Surface ABCA1 is internalized and degraded, and apoA-I interferes with only the latter step to recycle ABCA1 to the surface. Increase of surface ABCA1 results in the increase of generation of HDL.
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Affiliation(s)
- Rui Lu
- Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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38
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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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Hozoji M, Munehira Y, Ikeda Y, Makishima M, Matsuo M, Kioka N, Ueda K. Direct interaction of nuclear liver X receptor-beta with ABCA1 modulates cholesterol efflux. J Biol Chem 2008; 283:30057-63. [PMID: 18782758 DOI: 10.1074/jbc.m804599200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cholesterol is an essential component of eukaryotic cells; at the same time, however, hyperaccumulation of cholesterol is harmful. Therefore, the ABCA1 gene, the product of which mediates secretion of cholesterol, is highly regulated at both the transcriptional and post-transcriptional levels. The transcription of ABCA1 is regulated by intracellular oxysterol concentration via the nuclear liver X receptor (LXR)/retinoid X receptor (RXR); once synthesized, ABCA1 protein turns over rapidly with a half-life of 1-2 h. Here, we show that the LXRbeta/RXR complex binds directly to ABCA1 on the plasma membrane of macrophages and modulates cholesterol secretion. When cholesterol does not accumulate, ABCA1-LXRbeta/RXR localizes on the plasma membrane, but is inert. When cholesterol accumulates, oxysterols bind to LXRbeta, and the LXRbeta/RXR complex dissociates from ABCA1, restoring ABCA1 activity and allowing apoA-I-dependent cholesterol secretion. LXRbeta can exert an immediate post-translational response, as well as a rather slow transcriptional response, to changes in cellular cholesterol accumulation. Thus, we provide the first demonstration that protein-protein interaction suppresses ABCA1 function. Furthermore, we show that LXRbeta is involved in both the transcriptional and post-transcriptional regulation of the ABCA1 transporter.
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Affiliation(s)
- Masako Hozoji
- Laboratory of Cellular Biochemistry, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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40
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Tamehiro N, Zhou S, Okuhira K, Benita Y, Brown CE, Zhuang DZ, Latz E, Hornemann T, von Eckardstein A, Xavier RJ, Freeman MW, Fitzgerald ML. SPTLC1 binds ABCA1 to negatively regulate trafficking and cholesterol efflux activity of the transporter. Biochemistry 2008; 47:6138-47. [PMID: 18484747 DOI: 10.1021/bi800182t] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ABCA1 transport of cholesterol and phospholipids to nascent HDL particles plays a central role in lipoprotein metabolism and macrophage cholesterol homeostasis. ABCA1 activity is regulated both at the transcriptional level and at the post-translational level. To explore mechanisms involved in the post-translational regulation of the transporter, we have used affinity purification and mass spectrometry to identify proteins that bind ABCA1 and influence its activity. Previously, we demonstrated that an interaction between beta1-syntrophin stimulated ABCA1 activity, at least in part, be slowing the degradation of the transporter. This work demonstrates that one subunit of the serine palmitoyltransferase enzyme, SPTLC1, but not subunit 2 (SPTLC2), is copurified with ABCA1 and negatively regulates its function. In human THP-I macrophages and in mouse liver, the ABCA1-SPTLC1 complex was detected by co-immunoprecipitation, demonstrating that the interaction occurs in cellular settings where ABCA1 activity is critical for HDL genesis. Pharmacologic inhibition of SPTLC1 with myriocin, which resulted in the disruption of the SPTLC1-ABCA1 complex, and siRNA knockdown of SPTLC1 expression both stimulated ABCA1 efflux by nearly 60% ( p < 0.05). In contrast, dominant-negative mutants of SPTLC1 inhibited ABCA1 efflux, indicating that a reduced level of sphingomyelin synthesis could not explain the effect of myriocin on ABCA1 activity. In 293 cells, the SPTLC1 inhibition of ABCA1 activity led to the blockade of the exit of ABCA1 from the endoplasmic reticulum. In contrast, myriocin treatment of macrophages increased the level of cell surface ABCA1. In composite, these results indicate that the physical interaction of ABCA1 and SPTLC1 results in reduction of ABCA1 activity and that inhibition of this interaction produces enhanced cholesterol efflux.
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Affiliation(s)
- Norimasa Tamehiro
- Lipid Metabolism Unit and Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, Massachusetts 02114, USA
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41
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Abstract
Oxysterol binding to liver X receptors (LXR) increases the transcription of genes involved in cholesterol efflux and disposal, such as ABCA1 (ATP-binding cassette transporter A1). Other cytoplasmic sterol-binding proteins could interact with this pathway by sequestering or delivering substrates and ligands. One potential regulator is OSBP (oxysterol-binding protein), which is implicated in the integration of sterol sensing/transport with sphingomyelin synthesis and cell signaling. Since these activities could impact the cholesterol efflux pathway, we examined whether OSBP was involved in LXR regulation and in expression and activity of ABCA1. Suppression of OSBP in Chinese hamster ovary cells by RNA interference resulted in increased ABCA1 protein expression and cholesterol efflux activity following induction with oxysterols or the synthetic LXR agonist TO901317. OSBP knockdown in J774 macrophages also increased ABCA1 expression in the presence and absence of LXR agonists. OSBP depletion did not affect ABCA1 mRNA levels or LXR activity. Rather, OSBP silencing increased the half-life of ABCA1 protein by 3-fold. Sphingomyelin synthesis was suppressed in OSBP-depleted cells treated with 25-hydroxycholesterol but not TO901317 or 22-hydroxycholesterol and did not correlate with ABCA1 stabilization. Moreover, co-transfection experiments revealed that reduction of ABCA1 protein by OSBP was prevented by a mutation in the sterol-binding domain but not by mutations that abrogated interaction with the Golgi apparatus or endoplasmic reticulum. Thus, OSBP opposes the activity of LXR by negatively regulating ABCA1 activity in the cytoplasm by sterol-binding domain-dependent protein destabilization.
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Affiliation(s)
- Kristin Bowden
- Department of Pediatrics and Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS, Canada
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Albrecht DE, Sherman DL, Brophy PJ, Froehner SC. The ABCA1 cholesterol transporter associates with one of two distinct dystrophin-based scaffolds in Schwann cells. Glia 2008; 56:611-8. [PMID: 18286648 PMCID: PMC4335170 DOI: 10.1002/glia.20636] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cytoskeletal scaffolding complexes help organize specialized membrane domains with unique functions on the surface of cells. In this study, we define the scaffolding potential of the Schwann cell dystrophin glycoprotein complex (DGC) by establishing the presence of four syntrophin isoforms, (alpha1, beta1, beta2, and gamma2), and one dystrobrevin isoform, (alpha-dystrobrevin-1), in the abaxonal membrane. Furthermore, we demonstrate the existence of two separate DGCs in Schwann cells that divide the abaxonal membrane into spatially distinct domains, the DRP2/periaxin rich plaques and the Cajal bands that contain Dp116, utrophin, alpha-dystrobrevin-1 and four syntrophin isoforms. Finally, we show that the two different DGCs can scaffold unique accessory molecules in distinct areas of the Schwann cell membrane. Specifically, the cholesterol transporter ABCA1, associates with the Dp116/syntrophin complex in Cajal bands and is excluded from the DRP2/periaxin rich plaques.
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Affiliation(s)
- Douglas E Albrecht
- Department of Physiology and Biophysics, University of Washington, 1959 NE Pacific St, Box 357290, Seattle WA 98195-7290, USA
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Wang MD, Franklin V, Sundaram M, Kiss RS, Ho K, Gallant M, Marcel YL. Differential Regulation of ATP Binding Cassette Protein A1 Expression and ApoA-I Lipidation by Niemann-Pick Type C1 in Murine Hepatocytes and Macrophages. J Biol Chem 2007; 282:22525-33. [PMID: 17553802 DOI: 10.1074/jbc.m700326200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Niemann-Pick type C1 (Npc1) protein inactivation results in lipid accumulation in late endosomes and lysosomes, leading to a defect of ATP binding cassette protein A1 (Abca1)-mediated lipid efflux to apolipoprotein A-I (apoA-I) in macrophages and fibroblasts. However, the role of Npc1 in Abca1-mediated lipid efflux to apoA-I in hepatocytes, the major cells contributing to HDL formation, is still unknown. Here we show that, whereas lipid efflux to apoA-I in Npc1-null macrophages is impaired, the lipidation of endogenously synthesized apoA-I by low density lipoprotein-derived cholesterol or de novo synthesized cholesterol or phospholipids in Npc1-null hepatocytes is significantly increased by about 1-, 3-, and 8-fold, respectively. The increased cholesterol efflux reflects a major increase of Abca1 protein in Npc1-null hepatocytes, which contrasts with the decrease observed in Npc1-null macrophages. The increased Abca1 expression is largely post-transcriptional, because Abca1 mRNA is only slightly increased and Lxr alpha mRNA is not changed, and Lxr alpha target genes are reduced. This differs from the regulation of Abcg1 expression, which is up-regulated at both mRNA and protein levels in Npc1-null cells. Abca1 protein translation rate is higher in Npc1-null hepatocytes, compared with wild type hepatocytes as measured by [(35)S]methionine incorporation, whereas there is no difference for the degradation of newly synthesized Abca1 in these two types of hepatocytes. Cathepsin D, which we recently identified as a positive modulator of Abca1, is markedly increased at both mRNA and protein levels by Npc1 inactivation in hepatocytes but not in macrophages. Consistent with this, inhibition of cathepsin D with pepstatin A reduced the Abca1 protein level in both Npc1-inactivated and WT hepatocytes. Therefore, Abca1 expression is specifically regulated in hepatocytes, where Npc1 activity modulates cathepsin D expression and Abca1 protein translation rate.
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Affiliation(s)
- Ming-Dong Wang
- Lipoprotein and Atherosclerosis Research Group, University of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7, Canada
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44
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Orlowski S, Coméra C, Tercé F, Collet X. Lipid rafts: dream or reality for cholesterol transporters? EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:869-85. [PMID: 17576551 DOI: 10.1007/s00249-007-0193-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 05/11/2007] [Accepted: 05/15/2007] [Indexed: 01/12/2023]
Abstract
As a key constituent of the cell membranes, cholesterol is an endogenous component of mammalian cells of primary importance, and is thus subjected to highly regulated homeostasis at the cellular level as well as at the level of the whole body. This regulation requires adapted mechanisms favoring the handling of cholesterol in aqueous compartments, as well as its transfer into or out of membranes, involving membrane proteins. A membrane exhibits functional properties largely depending on its lipid composition and on its structural organization, which very often involves cholesterol-rich microdomains. Then there is the appealing possibility that cholesterol may regulate its own transmembrane transport at a purely functional level, independently of any transcriptional regulation based on cholesterol-sensitive nuclear factors controling the expression level of lipid transport proteins. Indeed, the main cholesterol "transporters" presently believed to mediate for instance the intestinal absorption of cholesterol, that are SR-BI, NPC1L1, ABCA1, ABCG1, ABCG5/G8 and even P-glycoprotein, all present privileged functional relationships with membrane cholesterol-containing microdomains. In particular, they all more or less clearly induce membrane disorganization, supposed to facilitate cholesterol exchanges with the close aqueous medium. The actual lipid substrates handled by these transporters are not yet unambiguously determined, but they likely concern the components of membrane microdomains. Conversely, raft alterations may provide specific modulations of the transporter activities, as well as they can induce indirect effects via local perturbations of the membrane. Finally, these cholesterol transporters undergo regulated intracellular trafficking, with presumably some relationships to rafts which remain to be clarified.
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Affiliation(s)
- Stéphane Orlowski
- SB2SM/IBTS and URA 2096 CNRS, CEA, Centre de Saclay, 91191, Gif-sur-Yvette cedex, France.
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45
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Cavelier C, Lorenzi I, Rohrer L, von Eckardstein A. Lipid efflux by the ATP-binding cassette transporters ABCA1 and ABCG1. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:655-66. [PMID: 16798073 DOI: 10.1016/j.bbalip.2006.04.012] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 04/05/2006] [Accepted: 04/28/2006] [Indexed: 11/23/2022]
Abstract
Plasma levels of high-density lipoproteins (HDL) and apolipoprotein A-I (apoA-I) are inversely correlated with the risk of cardiovascular disease. One major atheroprotective mechanism of HDL and apoA-I is their role in reverse cholesterol transport, i.e., the transport of excess cholesterol from foam cells to the liver for secretion. The ATP-binding cassette transporters ABCA1 and ABCG1 play a pivotal role in this process by effluxing lipids from foam cells to apoA-I and HDL, respectively. In the liver, ABCA1 activity is one rate-limiting step in the formation of HDL. In macrophages, ABCA1 and ABCG1 prevent the excessive accumulation of lipids and thereby protect the arteries from developing atherosclerotic lesions. However, the mechanisms by which ABCA1 and ABCG1 mediate lipid removal are still unclear. Particularly, three questions remain controversial and are discussed in this review: (1) Do apoA-I and HDL directly interact with ABCA1 and ABCG1, respectively? (2) Does cholesterol efflux involve retroendocytosis of apoA-I or HDL? (3) Which lipids are directly transported by ABCA1 and ABCG1?
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Affiliation(s)
- Clara Cavelier
- Institute of Clinical Chemistry, University Hospital Zurich, University Zurich, Rämistrasse 100, CH 8091 Zurich, Switzerland
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46
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Kaminski WE, Piehler A, Wenzel JJ. ABC A-subfamily transporters: Structure, function and disease. Biochim Biophys Acta Mol Basis Dis 2006; 1762:510-24. [PMID: 16540294 DOI: 10.1016/j.bbadis.2006.01.011] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 01/30/2006] [Accepted: 01/31/2006] [Indexed: 12/01/2022]
Abstract
ABC transporters constitute a family of evolutionarily highly conserved multispan proteins that mediate the translocation of defined substrates across membrane barriers. Evidence has accumulated during the past years to suggest that a subgroup of 12 structurally related "full-size" transporters, referred to as ABC A-subfamily transporters, mediates the transport of a variety of physiologic lipid compounds. The emerging importance of ABC A-transporters in human disease is reflected by the fact that as yet four members of this protein family (ABCA1, ABCA3, ABCR/ABCA4, ABCA12) have been causatively linked to completely unrelated groups of monogenetic disorders including familial high-density lipoprotein (HDL) deficiency, neonatal surfactant deficiency, degenerative retinopathies and congenital keratinization disorders. Although the biological function of the remaining 8 ABC A-transporters currently awaits clarification, they represent promising candidate genes for a presumably equally heterogenous group of Mendelian diseases associated with perturbed cellular lipid transport. This review summarizes our current knowledge on the role of ABC A-subfamily transporters in physiology and disease and explores clinical entities which may be potentially associated with dysfunctional members of this gene subfamily.
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Affiliation(s)
- Wolfgang E Kaminski
- Institute for Clinical Chemistry, Faculty for Clinical Medicine Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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47
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Nofer JR, Remaley AT, Feuerborn R, Wolinnska I, Engel T, von Eckardstein A, Assmann G. Apolipoprotein A-I activates Cdc42 signaling through the ABCA1 transporter. J Lipid Res 2006; 47:794-803. [PMID: 16443932 DOI: 10.1194/jlr.m500502-jlr200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It has been suggested that the signal transduction initiated by apolipoprotein A-I (apoA-I) activates key proteins involved in cholesterol efflux. ABCA1 serves as a binding partner for apoA-I, but its participation in apoA-I-induced signaling remains uncertain. We show that the exposure of human fibroblasts to ABCA1 ligands (apolipoproteins and amphipathic helical peptides) results in the generation of intracellular signals, including activation of the small G-protein Cdc42, protein kinases (PAK-1 and p54JNK), and actin polymerization. ApoA-I-induced signaling was abrogated by glyburide, an inhibitor of the ABC transporter family, and in fibroblasts from patients with Tangier disease, which do not express ABCA1. Conversely, induction of ABCA1 expression with the liver X receptor agonist, T0901317, and the retinoid X receptor agonist, R0264456, potentiated apoA-I-induced signaling. Similar effects were observed in HEK293 cells overexpressing ABCA1-green fluorescent protein (GFP) fusion protein, but not ABCA1-GFP (K939M), which fails to hydrolyze ATP, or a nonfunctional ABCA1-GFP with a truncated C terminus. We further found that Cdc42 coimmunoprecipitates with ABCA1 in ABCA1-GFP-expressing HEK293 cells exposed to apoA-I but not in cells expressing ABCA1 mutants. We conclude that ABCA1 transduces signals from apoA-I by complexing and activating Cdc42 and downstream kinases and, therefore, acts as a full apoA-I receptor.
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Affiliation(s)
- Jerzy-Roch Nofer
- Institut für Klinische Chemie und Laboratoriumsmedizin, Westfälische Wilhelms-Universität, Münster, Germany.
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