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Chang TY, Yamauchi Y, Hasan MT, Chang C. Cellular cholesterol homeostasis and Alzheimer's disease. J Lipid Res 2017; 58:2239-2254. [PMID: 28298292 DOI: 10.1194/jlr.r075630] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/14/2017] [Indexed: 01/12/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia in older adults. Currently, there is no cure for AD. The hallmark of AD is the accumulation of extracellular amyloid plaques composed of amyloid-β (Aβ) peptides (especially Aβ1-42) and neurofibrillary tangles, composed of hyperphosphorylated tau and accompanied by chronic neuroinflammation. Aβ peptides are derived from the amyloid precursor protein (APP). The oligomeric form of Aβ peptides is probably the most neurotoxic species; its accumulation eventually forms the insoluble and aggregated amyloid plaques. ApoE is the major apolipoprotein of the lipoprotein(s) present in the CNS. ApoE has three alleles, of which the Apoe4 allele constitutes the major risk factor for late-onset AD. Here we describe the complex relationship between ApoE4, oligomeric Aβ peptides, and cholesterol homeostasis. The review consists of four parts: 1) key elements involved in cellular cholesterol metabolism and regulation; 2) key elements involved in intracellular cholesterol trafficking; 3) links between ApoE4, Aβ peptides, and disturbance of cholesterol homeostasis in the CNS; 4) potential lipid-based therapeutic targets to treat AD. At the end, we recommend several research topics that we believe would help in better understanding the connection between cholesterol and AD for further investigations.
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Affiliation(s)
- Ta-Yuan Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Yoshio Yamauchi
- Nutri-Life Science Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Mazahir T Hasan
- Laboratory of Memory Circuits, Achucarro Basque Center for Neuroscience, Zamudio, Spain
| | - Catherine Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
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Bi X, Pashos EE, Cuchel M, Lyssenko NN, Hernandez M, Picataggi A, McParland J, Yang W, Liu Y, Yan R, Yu C, DerOhannessian SL, Phillips MC, Morrisey EE, Duncan SA, Rader DJ. ATP-Binding Cassette Transporter A1 Deficiency in Human Induced Pluripotent Stem Cell-Derived Hepatocytes Abrogates HDL Biogenesis and Enhances Triglyceride Secretion. EBioMedicine 2017; 18:139-145. [PMID: 28330813 PMCID: PMC5405159 DOI: 10.1016/j.ebiom.2017.03.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 11/05/2022] Open
Abstract
Despite the recognized role of the ATP-binding Cassette Transporter A1 (ABCA1) in high-density lipoprotein (HDL) metabolism, our understanding of ABCA1 deficiency in human hepatocytes is limited. To define the functional effects of human hepatocyte ABCA1 deficiency, we generated induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells (HLCs) from Tangier disease (TD) and matched control subjects. Control HLCs exhibited robust cholesterol efflux to apolipoprotein A-I (apoA-I) and formed nascent HDL particles. ABCA1-deficient HLCs failed to mediate lipid efflux or nascent HDL formation, but had elevated triglyceride (TG) secretion. Global transcriptome analysis revealed significantly increased ANGPTL3 expression in ABCA1-deficient HLCs. Angiopoietin-related protein 3 (ANGPTL3) was enriched in plasma of TD relative to control subjects. These results highlight the required role of ABCA1 in cholesterol efflux and nascent HDL formation by hepatocytes. Furthermore, our results suggest that hepatic ABCA1 deficiency results in increased hepatic TG and ANGPTL3 secretion, potentially underlying the elevated plasma TG levels in TD patients. ABCA1 deficiency in human hepatocytes abolishes nascent HDL formation, but elevates triglyceride secretion ABCA1 deficiency increases hepatic ANGPTL3 expression and secretion Tangier disease patients display higher plasma ANGPTL3 levels relative to normal HDL control subjects
ATP-Binding Cassette Transporter A1 (ABCA1) is a key regulator of high-density lipoprotein metabolism, but the intrinsic functional impact of human hepatocyte ABCA1 deficiency is yet to be defined. We generated hepatocyte-like cells (HLCs) from induced pluripotent stem cell (iPSC) of patients with Tangier disease (TD), a rare genetic disorder caused by mutations in ABCA1. ABCA1 deficiency in HLCs abrogates lipid efflux and nascent HDL formation but increases triglyceride secretion. ANGPTL3 has also been uncovered as a potential mediator of hypertriglyceridemia in TD. This study thus highlights the utility of iPSC-derived cells in disease modeling.
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Affiliation(s)
- Xin Bi
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Evanthia E Pashos
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marina Cuchel
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nicholas N Lyssenko
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mayda Hernandez
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Antonino Picataggi
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James McParland
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wenli Yang
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ying Liu
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ruilan Yan
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher Yu
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephanie L DerOhannessian
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael C Phillips
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Edward E Morrisey
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephen A Duncan
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, SC 29425, USA
| | - Daniel J Rader
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine of the University of Pennsylvania and Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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103
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Morris GE, Braund PS, Moore JS, Samani NJ, Codd V, Webb TR. Coronary Artery Disease-Associated LIPA Coding Variant rs1051338 Reduces Lysosomal Acid Lipase Levels and Activity in Lysosomes. Arterioscler Thromb Vasc Biol 2017; 37:1050-1057. [PMID: 28279971 PMCID: PMC5444428 DOI: 10.1161/atvbaha.116.308734] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/27/2017] [Indexed: 12/20/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— Genome-wide association studies have linked variants at chromosome 10q23 with increased coronary artery disease risk. The disease-associated variants fall in LIPA, which encodes lysosomal acid lipase (LAL), the enzyme responsible for lysosomal cholesteryl ester hydrolysis. Loss-of-function mutations in LIPA result in accelerated atherosclerosis. Surprisingly, the coronary artery disease variants are associated with increased LIPA expression in some cell types. In this study, we address this apparent contradiction. Approach and Results— We investigated a coding variant rs1051338, which is in high linkage disequilibrium (r2=0.89) with the genome-wide association study lead–associated variant rs2246833 and causes a nonsynonymous threonine to proline change within the signal peptide of LAL. Transfection of allele-specific expression constructs showed that the risk allele results in reduced lysosomal LAL protein (P=0.004) and activity (P=0.005). Investigation of LAL localization and turnover showed the risk LAL protein is degraded more quickly. This mechanism was confirmed in disease-relevant macrophages from individuals homozygous for either the nonrisk or risk allele. There was no difference in LAL protein or activity in whole macrophage extracts; however, we found reduced LAL protein (P=0.02) and activity (P=0.026) with the risk genotype in lysosomal extracts, suggesting that the risk genotype affects lysosomal LAL activity. Inhibition of the proteasome resulted in equal amounts of lysosomal LAL protein in risk and nonrisk macrophages. Conclusions— Our findings show that the coronary artery disease–associated coding variant rs1051338 causes reduced lysosomal LAL protein and activity because of increased LAL degradation, providing a plausible causal mechanism of increased coronary artery disease risk.
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Affiliation(s)
- Gavin E Morris
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Peter S Braund
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Jasbir S Moore
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Nilesh J Samani
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Veryan Codd
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Tom R Webb
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom.
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104
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Downing LE, Edgar D, Ellison PA, Ricketts ML. Mechanistic insight into nuclear receptor-mediated regulation of bile acid metabolism and lipid homeostasis by grape seed procyanidin extract (GSPE). Cell Biochem Funct 2017; 35:12-32. [DOI: 10.1002/cbf.3247] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Laura E. Downing
- Department of Agriculture, Nutrition and Veterinary Sciences; University of Nevada Reno; Reno Nevada USA
| | - Daniel Edgar
- Department of Biochemistry and Molecular Biology; University of Nevada Reno; Reno Nevada USA
| | - Patricia A. Ellison
- Department of Biochemistry and Molecular Biology; University of Nevada Reno; Reno Nevada USA
| | - Marie-Louise Ricketts
- Department of Agriculture, Nutrition and Veterinary Sciences; University of Nevada Reno; Reno Nevada USA
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105
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Oda MN. Lipid-free apoA-I structure - Origins of model diversity. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:221-233. [PMID: 27890580 DOI: 10.1016/j.bbalip.2016.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 10/20/2016] [Accepted: 11/20/2016] [Indexed: 01/22/2023]
Abstract
Apolipoprotein A-I (apoA-I) is a prominent member of the exchangeable apolipoprotein class of proteins, capable of transitioning between lipid-bound and lipid-free states. It is the primary structural and functional protein of high density lipoprotein (HDL). Lipid-free apoA-I is critical to de novo HDL formation as it is the preferred substrate of the lipid transporter, ATP Binding Cassette Transporter A1 (ABCA1) Remaley et al. (2001) [1]. Lipid-free apoA-I is an important element in reverse cholesterol transport and comprehension of its structure is a core issue in our understanding of cholesterol metabolism. However, lipid-free apoA-I is highly conformationally dynamic making it a challenging subject for structural analysis. Over the past 20years there have been significant advances in overcoming the dynamic nature of lipid-free apoA-I, which have resulted in a multitude of proposed conformational models.
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Affiliation(s)
- Michael N Oda
- Children's Hospital Oakland Research Institute, Oakland, CA 94609, United States.
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106
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Hirota T, Tanaka T, Takesue H, Ieiri I. Epigenetic regulation of drug transporter expression in human tissues. Expert Opin Drug Metab Toxicol 2016; 13:19-30. [DOI: 10.1080/17425255.2017.1230199] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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107
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Zhang T, Zhou L, Li CC, Shi H, Zhou X. TSH increases synthesis of hepatic ATP-binding cassette subfamily A member 1 in hypercholesterolemia. Biochem Biophys Res Commun 2016; 476:75-81. [PMID: 27179782 DOI: 10.1016/j.bbrc.2016.05.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/10/2016] [Indexed: 10/21/2022]
Abstract
Epidemiological evidence suggests that thyrotropin (TSH) levels are closely correlated with the severity of hypercholesterolemia. Reverse cholesterol transfer (RCT) plays an important role in regulating bloodcholesterol. However, the molecular mechanism of hypercholesterolemia in subclinical hypothyroidism (SCH) has not been fully clarified. The SCH mouse model, which is characterized by elevated serum TSH but not thyroid hormone levels, demonstrated a significant increase in plasma cholesterol compared with controls. Interestingly, Tshr KO mice, with normal thyroid hormone levels after thyroid hormone supplementation, showed lower plasma cholesterol levels compared with their wild-type littermates. ATP binding cassette subfamily A member 1(ABCA1) is a member of the ABC superfamily, which induces transfer of intracellular cholesterol to extracellular apolipoprotein. TSH upregulated hepatic ABCA1 to promote the efflux of intercellular cumulative cholesterol, resulting in increased plasma cholesterol. These data might partially explain the pathogenesis of hypercholesterolemia in SCH.
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Affiliation(s)
- Tiantian Zhang
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Shandong Clinical Medical Center of Endocrinology and Metabolism, Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, China
| | - Lingyan Zhou
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Shandong Clinical Medical Center of Endocrinology and Metabolism, Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, China
| | - Cong Cong Li
- Jinan Central Hospital affiliated to Shandong University, Jinan, Shandong, 250021, China
| | - Hong Shi
- Department of Pediatrics, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, China
| | - Xinli Zhou
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Shandong Clinical Medical Center of Endocrinology and Metabolism, Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, China.
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108
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Miller NE, Olszewski WL, Miller IP, Nanjee MN. Mechanism and Physiologic Significance of the Suppression of Cholesterol Esterification in Human Interstitial Fluid. Front Pharmacol 2016; 7:216. [PMID: 27471469 PMCID: PMC4945636 DOI: 10.3389/fphar.2016.00216] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/05/2016] [Indexed: 11/13/2022] Open
Abstract
Cholesterol esterification in high density lipoproteins (HDLs) by lecithin:cholesterol acyltransferase (LCAT) promotes unesterified cholesterol (UC) transfer from red cell membranes to plasma in vitro. However, it does not explain the transfer of UC from most peripheral cells to interstitial fluid in vivo, as HDLs in afferent peripheral lymph are enriched in UC. Having already reported that the endogenous cholesterol esterification rate (ECER) in lymph is only 5% of that in plasma, we have now explored the underlying mechanism. In peripheral lymph from 20 healthy men, LCAT concentration, LCAT activity (assayed using an optimized substrate), and LCAT specific activity averaged, respectively, 11.8, 10.3, and 84.9% of plasma values. When recombinant human LCAT was added to lymph, the increments in enzyme activity were similar to those when LCAT was added to plasma. Addition of apolipoprotein AI (apo AI), fatty acid-free albumin, Intralipid, or the d < 1.006 g/ml plasma fraction had no effect on ECER. During incubation of lymph plus plasma, the ECER was similar to that observed with buffer plus plasma. When lymph was added to heat-inactivated plasma, the ECER was 11-fold greater than with lymph plus buffer. Addition of discoidal proteoliposomes of apo AI and phosphatidycholine (PC) to lymph increased ECER 10-fold, while addition of apo AI/PC/UC disks did so by only six-fold. We conclude that the low ECER in lymph is due to a property of the HDLs, seemingly substrate inhibition of LCAT by excess cell-derived UC. This is reversed when lymph enters plasma, consequent upon redistribution of UC from lymph HDLs to plasma lipoproteins.
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Affiliation(s)
| | - Waldemar L Olszewski
- Department of Surgical Research and Transplantology, Medical Research Centre, Polish Academy of Sciences, Warsaw Poland
| | - Irina P Miller
- Department of Cardiovascular Biochemistry, Queen Mary University of London, London UK
| | - Mahmud N Nanjee
- Cardiovascular Genetics Unit, School of Medicine, University of Utah, Salt Lake City, UT USA
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109
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Demina EP, Miroshnikova VV, Schwarzman AL. Role of the ABC transporters A1 and G1, key reverse cholesterol transport proteins, in atherosclerosis. Mol Biol 2016. [DOI: 10.1134/s0026893316020047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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110
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Fawzy MS, Alhadramy O, Hussein MH, Ismail HM, Ismail NM, Biomy NM, Toraih EA. Functional and Structural Impact of ATP-Binding Cassette Transporter A1 R219K and I883M Gene Polymorphisms in Obese Children and Adolescents. Mol Diagn Ther 2016; 19:221-34. [PMID: 26243156 DOI: 10.1007/s40291-015-0150-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Obesity is a serious medical condition that affects children and adolescents. ATP-binding cassette transporter A1 (ABCA1) protein is known to mediate the transport of intracellular cholesterol and phospholipids across the cell membranes. Thus, we aimed to investigate the association between ABCA1 gene polymorphisms and overweight/obesity risk, and to evaluate their relation to the lipid profile. MATERIALS AND METHODS The study included in silico analysis of ABCA1 gene and protein. Two genetic variants in ABCA1 gene-R219K (rs2230806; G/A) and I883M (rs2066714; A/G)-were genotyped in 128 normal weight and 128 overweight/obese subjects using polymerase chain reaction-restriction fragment length polymorphism technology. Anthropometric and biochemical assessments were performed. RESULTS Our findings suggest that the heterozygote GA genotype of R219K polymorphism increased susceptibility to obesity under the heterozygous model (odds ratio 2.75, 95 % CI 1.01-6.12; p = 0.014) compared with the control group. This susceptibility could be gender-specific, with higher risk among females. In addition, the A variant was associated with a higher degree of obesity (p < 0.001). On the other hand, individuals with the G variant of I883M polymorphism showed lower susceptibility to obesity under all genetic models (allelic, homozygote, heterozygote, dominant, and recessive models; p < 0.05), with no observed association with body mass index or degree of obesity. However, both single nucleotide polymorphisms (SNPs) showed significant differences in lipid levels among patients with different genotypes. CONCLUSIONS The study results suggest that R219K and I883M SNPs of the ABCA1 gene may play a role in susceptibility to obesity in our Egyptian population; the former increases susceptibility and phenotype severity, and the latter is protective. Larger epidemiological studies are needed for validation of the results.
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Affiliation(s)
- Manal S Fawzy
- Department of Medical Biochemistry, Faculty of Medicine, Suez Canal University, Ismailia, Egypt,
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111
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Apolipoprotein A-I Mimetic Peptide D-4F Reduces Cardiac Hypertrophy and Improves Apolipoprotein A-I–Mediated Reverse Cholesterol Transport From Cardiac Tissue in LDL Receptor-null Mice Fed a Western Diet. J Cardiovasc Pharmacol 2016; 67:412-7. [DOI: 10.1097/fjc.0000000000000365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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112
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The cholesterol transporter ABCA1 is expressed in stallion spermatozoa and reproductive tract tissues. Theriogenology 2016; 85:1080-9. [DOI: 10.1016/j.theriogenology.2015.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 10/30/2015] [Accepted: 11/24/2015] [Indexed: 11/20/2022]
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113
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Wen W, He M, Liang X, Gao SS, Zhou J, Yuan ZY. Accelerated transformation of macrophage-derived foam cells in the presence of collagen-induced arthritis mice serum is associated with dyslipidemia. Autoimmunity 2016; 49:115-23. [PMID: 26955845 DOI: 10.3109/08916934.2015.1118761] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Atherosclerosis characterized by accumulation of foam cells in the arterial intimal layer is accelerated in rheumatoid arthritis (RA) patients. We and others have previously demonstrated that serum from RA patients and collagen-induced arthritis (CIA) mice had proatherogenic features that might lead to progression of atherosclerosis. Here we further examined the effects of serum from CIA mice on the transformation of macrophage-derived foam cells, and investigated potential mechanism. METHODS DBA/1j mice were used to establish CIA model. Murine peritoneal macrophages and macrophage cell line RAW264.7 were treated with different dilute concentrations of mice serum. RESULTS CIA mice serum increased cholesterol influx and accumulation in murine macrophages, and markedly up-regulated scavenger receptor CD36 expression in the cells, but had no effect on intracellular lipid efflux. Neutralizing monocyte chemotactic protein (MCP)-1, the most significant altered cytokine we observed between normal and CIA mice serum to CIA mice could not reverse these effects. However, administering simvastatin to CIA mice could lower high-density lipoprotein-cholesterol (HDL-C) level and elevate oxidized low-density lipoprotein (ox-LDL) level in CIA mice serum, with attendant decreased lipid accumulation as well as CD36 expression in murine macrophages. CONCLUSION Accelerated transformation of macrophage-derived foam cells via up-regulated CD36 expression is related to dyslipidemia rather than elevated inflammatory factor MCP-1 level in CIA mice serum. Decreased HDL-C and higher ox-LDL levels in CIA mice serum may link RA to atherosclerosis.
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Affiliation(s)
- Wen Wen
- a Department of Cardiovascular Medicine and
| | - Ming He
- b Department of Rheumatology, First Affiliated Hospital of Medical School , Xi'an Jiaotong University , Shaanxi , PR China , and
| | - Xiao Liang
- a Department of Cardiovascular Medicine and
| | | | - Juan Zhou
- a Department of Cardiovascular Medicine and
| | - Zu-yi Yuan
- a Department of Cardiovascular Medicine and.,c Key Laboratory of Environment and Genes Related to Diseases , Xi'an Jiaotong University, Ministry of Education , Xi'an, Shaanxi , PR China
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114
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Update on Mechanisms of Renal Tubule Injury Caused by Advanced Glycation End Products. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5475120. [PMID: 27034941 PMCID: PMC4789391 DOI: 10.1155/2016/5475120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/08/2016] [Indexed: 01/26/2023]
Abstract
Diabetic nephropathy (DN) caused by advanced glycation end products (AGEs) may be associated with lipid accumulation in the kidneys. This study was designed to investigate whether Nε-(carboxymethyl) lysine (CML, a member of the AGEs family) increases lipid accumulation in a human renal tubular epithelial cell line (HK-2) via increasing cholesterol synthesis and uptake and reducing cholesterol efflux through endoplasmic reticulum stress (ERS). Our results showed that CML disrupts cholesterol metabolism in HK-2 cells by activating sterol regulatory element-binding protein 2 (SREBP-2) and liver X receptor (LXR), followed by an increase in 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR) mediated cholesterol synthesis and low density lipoprotein receptor (LDLr) mediated cholesterol uptake and a reduction in ATP-binding cassette transporter A1 (ABCA1) mediated cholesterol efflux, ultimately causing lipid accumulation in HK-2 cells. All of these responses could be suppressed by an ERS inhibitor, which suggests that CML causes lipid accumulation in renal tubule cells through ERS and that the inhibition of ERS is a potential novel approach to treating CML-induced renal tubular foam cell formation.
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115
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Yao MH, He J, Ma RL, Ding YS, Guo H, Yan YZ, Zhang JY, Liu JM, Zhang M, Rui DS, Niu Q, Guo SX. Association between Polymorphisms and Haplotype in the ABCA1 Gene and Overweight/Obesity Patients in the Uyghur Population of China. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:220. [PMID: 26891315 PMCID: PMC4772240 DOI: 10.3390/ijerph13020220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/13/2016] [Accepted: 01/27/2016] [Indexed: 12/20/2022]
Abstract
OBJECTIVE This study aimed to detect the association between polymorphisms and haplotype in the ATP-binding cassette transporter A1 (ABCA1) gene and overweight/obese Uyghur patients in China. METHODS A total of 259 overweight/obese patients and 276 normal weight subjects, which were randomly selected from among 3049 adult Uyghurs, were matched for age. We genotyped ABCA1 single nucleotide polymorphisms of rs2515602, rs3890182, rs2275542, rs2230806, rs1800976, and rs4149313. RESULTS (1) The genotypic and allelic frequencies of rs2515602 and rs4149313 differed between the control group and case group. The genotypic frequency of rs2275542 also differed between the control group and case group (p < 0.05); (2) rs2515602, rs2230806, and rs4149313 polymorphisms were significantly related to risk of overweight/obese; (3) a significant linkage disequilibrium (LD) was observed between the ABCA1 gene rs2275542 with rs3890182 and rs2515602 with rs4149313. (4) the C-C-C-A-G-G, T-C-G-A-G-G, and T-T-G-G-G-A haplotypes were significant in normal weight and overweight/obese subjects (p < 0.05); (5) the levels of HDL-C (rs2515602, rs2275542, rs4149313) in normal weight subjects were different among the genotypes (p < 0.05); the levels of TC, LDL-C and TG (rs1800976) in overweight/obese subjects were different among the genotypes (p < 0.05). CONCLUSIONS The rs2515602, rs4149313, and rs2275542 polymorphisms were associated with overweight/obese conditions among Uyghurs. Strong LD was noted between rs2275542 with rs3890182 and rs2515602 with rs4149313. The C-C-C-A-G-G and T-C-G-A-G-G haplotypes may serve as risk factors of overweight/obesity among Uyghurs. The T-T-G-G-G-A haplotype may serve as a protective factor of overweight/obesity among Uyghurs. Rs2515602, rs2275542, rs4149313, and rs1800976 polymorphisms in the ABCA1 gene may influence lipid profiles.
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Affiliation(s)
- Ming-Hong Yao
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Jia He
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Ru-Lin Ma
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Yu-Song Ding
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Heng Guo
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Yi-Zhong Yan
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Jing-Yu Zhang
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Jia-Ming Liu
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Mei Zhang
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Dong-Shen Rui
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Qiang Niu
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
| | - Shu-Xia Guo
- Department of Public Health and Key Laboratory of Xinjiang Endemic and Ethnic Diseases of the Ministry of Education, Shihezi University School of Medicine, Shihezi 832002, China.
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Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
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Lv O, Wang L, Li J, Ma Q, Zhao W. Effects of pomegranate peel polyphenols on lipid accumulation and cholesterol metabolic transformation in L-02 human hepatic cells via the PPARγ-ABCA1/CYP7A1 pathway. Food Funct 2016; 7:4976-4983. [DOI: 10.1039/c6fo01261b] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PPPs, PC and PEA in different concentrations were found to decrease the total cholesterol (TC) content and increase the total bile acid (TBA) content of a human hepatic cell model, and so possess a lipid-lowering effect.
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Affiliation(s)
- Ou Lv
- College of Food Engineering and Nutritional Science
- Shaanxi Normal University
- Xi'an
- P. R. China
| | - Lifang Wang
- College of Food Engineering and Nutritional Science
- Shaanxi Normal University
- Xi'an
- P. R. China
| | - Jianke Li
- College of Food Engineering and Nutritional Science
- Shaanxi Normal University
- Xi'an
- P. R. China
- University Key Laboratory of Food Processing Byproducts for Advanced Development and High Value Utilization
| | - Qianqian Ma
- College of Food Engineering and Nutritional Science
- Shaanxi Normal University
- Xi'an
- P. R. China
| | - Wei Zhao
- College of Food Engineering and Nutritional Science
- Shaanxi Normal University
- Xi'an
- P. R. China
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118
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Ronsein GE, Hutchins PM, Isquith D, Vaisar T, Zhao XQ, Heinecke JW. Niacin Therapy Increases High-Density Lipoprotein Particles and Total Cholesterol Efflux Capacity But Not ABCA1-Specific Cholesterol Efflux in Statin-Treated Subjects. Arterioscler Thromb Vasc Biol 2015; 36:404-11. [PMID: 26681752 DOI: 10.1161/atvbaha.115.306268] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 12/09/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We investigated relationships between statin and niacin/statin combination therapy and the concentration of high-density lipoprotein particles (HDL-P) and cholesterol efflux capacity, 2 HDL metrics that might better assess cardiovascular disease risk than HDL-cholesterol (HDL-C) levels. APPROACH In the Carotid Plaque Composition Study, 126 subjects with a history of cardiovascular disease were randomized to atorvastatin or combination therapy (atorvastatin/niacin). At baseline and after 1 year of treatment, the concentration of HDL and its 3 subclasses (small, medium, and large) were quantified by calibrated ion mobility analysis (HDL-PIMA). We also measured total cholesterol efflux from macrophages and ATP-binding cassette transporter A1 (ABCA1)-specific cholesterol efflux capacity. RESULTS Atorvastatin decreased low-density lipoprotein cholesterol by 39% and raised HDL-C by 11% (P=0.0001) but did not increase HDL-PIMA or macrophage cholesterol efflux. Combination therapy raised HDL-C by 39% (P<0.0001) but increased HDL-PIMA by only 14%. Triglyceride levels did not correlate with HDL-PIMA (P=0.39), in contrast to their strongly negative correlation with HDL-C (P<0.0001). Combination therapy increased macrophage cholesterol efflux capacity (16%, P<0.0001) but not ABCA1-specific efflux. ABCA1-specific cholesterol efflux capacity decreased significantly (P=0.013) in statin-treated subjects, with or without niacin therapy. CONCLUSIONS Statin therapy increased HDL-C levels but failed to increase HDL-PIMA. It also reduced ABCA1-specific cholesterol efflux capacity. Adding niacin to statin therapy increased HDL-C and macrophage efflux, but had much less effect on HDL-PIMA. It also failed to improve ABCA1-specific efflux, a key cholesterol exporter in macrophages. Our observations raise the possibility that niacin might not target the relevant atheroprotective population of HDL.
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Affiliation(s)
| | | | - Daniel Isquith
- From the Department of Medicine, University of Washington, Seattle
| | - Tomas Vaisar
- From the Department of Medicine, University of Washington, Seattle
| | - Xue-Qiao Zhao
- From the Department of Medicine, University of Washington, Seattle
| | - Jay W Heinecke
- From the Department of Medicine, University of Washington, Seattle.
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Pamir N, Hutchins P, Ronsein G, Vaisar T, Reardon CA, Getz GS, Lusis AJ, Heinecke JW. Proteomic analysis of HDL from inbred mouse strains implicates APOE associated with HDL in reduced cholesterol efflux capacity via the ABCA1 pathway. J Lipid Res 2015; 57:246-57. [PMID: 26673204 PMCID: PMC4727420 DOI: 10.1194/jlr.m063701] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 12/15/2022] Open
Abstract
Cholesterol efflux capacity associates strongly and negatively with the incidence and prevalence of human CVD. We investigated the relationships of HDL’s size and protein cargo with its cholesterol efflux capacity using APOB-depleted serum and HDLs isolated from five inbred mouse strains with different susceptibilities to atherosclerosis. Like humans, mouse HDL carried >70 proteins linked to lipid metabolism, the acute-phase response, proteinase inhibition, and the immune system. HDL’s content of specific proteins strongly correlated with its size and cholesterol efflux capacity, suggesting that its protein cargo regulates its function. Cholesterol efflux capacity with macrophages strongly and positively correlated with retinol binding protein 4 (RBP4) and PLTP, but not APOA1. In contrast, ABCA1-specific cholesterol efflux correlated strongly with HDL’s content of APOA1, APOC3, and APOD, but not RBP4 and PLTP. Unexpectedly, APOE had a strong negative correlation with ABCA1-specific cholesterol efflux capacity. Moreover, the ABCA1-specific cholesterol efflux capacity of HDL isolated from APOE-deficient mice was significantly greater than that of HDL from wild-type mice. Our observations demonstrate that the HDL-associated APOE regulates HDL’s ABCA1-specific cholesterol efflux capacity. These findings may be clinically relevant because HDL’s APOE content associates with CVD risk and ABCA1 deficiency promotes unregulated cholesterol accumulation in human macrophages.
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Affiliation(s)
- Nathalie Pamir
- Department of Medicine, University of Washington, Seattle, WA
| | | | | | - Tomas Vaisar
- Department of Medicine, University of Washington, Seattle, WA
| | | | - Godfrey S Getz
- Department of Pathology, University of Chicago, Chicago, IL
| | - Aldons J Lusis
- Department of Genetics, University of California at Los Angeles, Los Angeles, CA
| | - Jay W Heinecke
- Department of Medicine, University of Washington, Seattle, WA
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Cholesterol Transporters ABCA1 and ABCG1 Gene Expression in Peripheral Blood Mononuclear Cells in Patients with Metabolic Syndrome. CHOLESTEROL 2015; 2015:682904. [PMID: 26788366 PMCID: PMC4692991 DOI: 10.1155/2015/682904] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 10/24/2015] [Accepted: 11/17/2015] [Indexed: 01/09/2023]
Abstract
ABCA1 and ABCG1 genes encode the cholesterol transporter proteins that play a key role in cholesterol and phospholipids homeostasis. This study was aimed at evaluating and comparing ABCA1 and ABCG1 genes expression in metabolic syndrome patients and healthy individuals. This case-control study was performed on 36 patients with metabolic syndrome and the same number of healthy individuals in Hamadan (west of Iran) during 2013-2014. Total RNA was extracted from mononuclear cells and purified using RNeasy Mini Kit column. The expression of ABCA1 and ABCG1 genes was performed by qRT-PCR. Lipid profile and fasting blood glucose were measured using colorimetric procedures. ABCG1 expression in metabolic syndrome patients was significantly lower (about 75%) compared to that of control group, while for ABCA1 expression, there was no significant difference between the two studied groups. Comparison of other parameters such as HDL-C, FBS, BMI, waist circumference, and systolic and diastolic blood pressure between metabolic syndrome patients and healthy individuals showed significant differences (P < 0.05). Decrease in ABCG1 expression in metabolic syndrome patients compared to healthy individuals suggests that hyperglycemia, related metabolites, and hyperlipidemia over the transporter capacity resulted in decreased expression of ABCG1. Absence of a significant change in ABCA1 gene expression between two groups can indicate a different regulation mechanism for ABCA1 expression.
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121
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Structural analysis of APOB variants, p.(Arg3527Gln), p.(Arg1164Thr) and p.(Gln4494del), causing Familial Hypercholesterolaemia provides novel insights into variant pathogenicity. Sci Rep 2015; 5:18184. [PMID: 26643808 PMCID: PMC4672294 DOI: 10.1038/srep18184] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 11/13/2015] [Indexed: 12/27/2022] Open
Abstract
Familial hypercholesterolaemia (FH) is an inherited autosomal dominant disorder resulting from defects in the low-density lipoprotein receptor (LDLR), in the apolipoprotein B (APOB) or in the proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. In the majority of the cases FH is caused by mutations occurring within LDLR, while only few mutations in APOB and PCSK9 have been proved to cause disease. p.(Arg3527Gln) was the first mutation in APOB being identified and characterized. Recently two novel pathogenic APOB variants have been described: p.(Arg1164Thr) and p.(Gln4494del) showing impaired LDLR binding capacity, and diminished LDL uptake. The objective of this work was to analyse the structure of p.(Arg1164Thr) and p.(Gln4494del) variants to gain insight into their pathogenicity. Secondary structure of the human ApoB100 has been investigated by infrared spectroscopy (IR) and LDL particle size both by dynamic light scattering (DLS) and electron microscopy. The results show differences in secondary structure and/or in particle size of p.(Arg1164Thr) and p.(Gln4494del) variants compared with wild type. We conclude that these changes underlie the defective binding and uptake of p.(Arg1164Thr) and p.(Gln4494del) variants. Our study reveals that structural studies on pathogenic variants of APOB may provide very useful information to understand their role in FH disease.
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122
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Gonadal Transcriptome Analysis in Sterile Double Haploid Japanese Flounder. PLoS One 2015; 10:e0143204. [PMID: 26580217 PMCID: PMC4651314 DOI: 10.1371/journal.pone.0143204] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 11/02/2015] [Indexed: 11/25/2022] Open
Abstract
Sterility is a serious problem that can affect all bionts. In teleosts, double haploids (DHs) induced by mitogynogenesis are often sterile. This sterility severely restricts the further application of DHs for production of clones, genetic analysis, and breeding. However, sterile DH individuals are good source materials for investigation of the molecular mechanisms of gonad development, especially for studies into the role of genes that are indispensable for fish reproduction. Here, we used the Illumina sequencing platform to analyze the transcriptome of sterile female DH Japanese flounder in order to identify major genes that cause sterility and to provide a molecular basis for an intensive study of gonadal development in teleosts. Through sequencing, assembly, and annotation, we obtained 52,474 contigs and found that 60.7% of these shared homologies with existing sequences. A total of 1225 differentially expressed unigenes were found, including 492 upregulated and 733 downregulated genes. Gene Ontology and KEGG analyses showed that genes showing significant upregulation, such as CYP11A1, CYP11B2, CYP17, CYP21, HSD3β, bcl2l1, and PRLR, principally correlated with sterol metabolic process, steroid biosynthetic process, and the Jak-stat signaling pathway. The significantly downregulated genes were primarily associated with immune response, antigen processing and presentation, cytokine–cytokine receptor interaction, and protein digestion and absorption. Using a co-expression network analysis, we conducted a comprehensive comparison of gene expression in the gonads of fertile and sterile female DH Japanese flounder. Identification of genes showing significantly different expression will provide further insights into DH reproductive dysfunction and oocyte maturation processes in teleosts.
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123
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Jacobo-Albavera L, Posadas-Romero C, Vargas-Alarcón G, Romero-Hidalgo S, Posadas-Sánchez R, González-Salazar MDC, Carnevale A, Canizales-Quinteros S, Medina-Urrutia A, Antúnez-Argüelles E, Villarreal-Molina T. Dietary fat and carbohydrate modulate the effect of the ATP-binding cassette A1 (ABCA1) R230C variant on metabolic risk parameters in premenopausal women from the Genetics of Atherosclerotic Disease (GEA) Study. Nutr Metab (Lond) 2015; 12:45. [PMID: 26579206 PMCID: PMC4647664 DOI: 10.1186/s12986-015-0040-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/09/2015] [Indexed: 12/16/2022] Open
Abstract
Background Although the R230C-ATP-binding cassette A1 (ABCA1) variant has been consistently associated with HDL-C levels, its association with diabetes and other metabolic parameters is unclear. Estrogen and dietary factors are known to regulate ABCA1 expression in different tissues. Thus, we aimed to explore whether gender, menopausal status and macronutrient proportions of diet modulate the effect of this variant on various metabolic parameters. Methods One thousand five hundred ninety-eight controls from the GEA study were included (787 men, 363 premenopausal women and 448 menopausal women), previously assessed for anthropometric and biochemical measurements and visceral to subcutaneous abdominal fat (VAT/SAT) ratio on computed tomography. Taqman assays were performed for genotyping. Diet macronutrient proportions were assessed using a food frequency questionnaire validated for the Mexican population. Multivariate regression models were constructed to assess the interaction between the proportion of dietary macronutrients and the R230C polymorphism on metabolic parameters. Results All significant interactions were observed in premenopausal women. Those carrying the risk allele and consuming higher carbohydrate/lower fat diets showed an unfavorable metabolic pattern [lower HDL-C and adiponectin levels, higher VAT/SAT ratio, homeostasis model assessment for insulin resistance (HOMA-IR) and higher gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP) levels]. Conversely, premenopausal women carrying the risk allele and consuming lower carbohydrate/higher fat diets showed a more favorable metabolic pattern (higher HDL-C and adiponectin levels, and lower VAT/SAT ratio, HOMA-IR, GGT and ALP levels). Conclusion This is the first study reporting a gender-specific interaction between ABCA1/R230C variant and dietary carbohydrate and fat percentages affecting VAT/SAT ratio, GGT, ALP, adiponectin levels and HOMA index. Our study confirmed the previously reported gender-specific ABCA1-diet interaction affecting HDL-C levels observed in an independent study. Our results show how gene-environment interactions may help further understand how certain gene variants confer metabolic risk, and may provide information useful to design diet intervention studies. Electronic supplementary material The online version of this article (doi:10.1186/s12986-015-0040-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leonor Jacobo-Albavera
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Carlos Posadas-Romero
- Departamento de Endocrinología, Instituto Nacional de Cardiología "Ignacio Chávez", Mexico City, Mexico
| | - Gilberto Vargas-Alarcón
- Departamento de Biología Molecular, Instituto Nacional de Cardiología "Ignacio Chávez", Mexico City, Mexico
| | - Sandra Romero-Hidalgo
- Departamento de Genómica Computacional, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Rosalinda Posadas-Sánchez
- Departamento de Endocrinología, Instituto Nacional de Cardiología "Ignacio Chávez", Mexico City, Mexico
| | | | - Alessandra Carnevale
- Laboratorio de Enfermedades Mendelianas, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Samuel Canizales-Quinteros
- Unidad de Genómica de Poblaciones Aplicada a la Salud, Facultad de Química UNAM-INMEGEN, Mexico City, Mexico
| | - Aida Medina-Urrutia
- Departamento de Endocrinología, Instituto Nacional de Cardiología "Ignacio Chávez", Mexico City, Mexico
| | - Erika Antúnez-Argüelles
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Periférico Sur 4809 Colonia Arenal Tepepan, CP 14610 México, D.F. Mexico
| | - Teresa Villarreal-Molina
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Periférico Sur 4809 Colonia Arenal Tepepan, CP 14610 México, D.F. Mexico
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124
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Phagocytosis of apoptotic cells in homeostasis. Nat Immunol 2015; 16:907-17. [PMID: 26287597 DOI: 10.1038/ni.3253] [Citation(s) in RCA: 534] [Impact Index Per Article: 59.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/17/2015] [Indexed: 02/07/2023]
Abstract
Human bodies collectively turn over about 200 billion to 300 billion cells every day. Such turnover is an integral part of embryonic and postnatal development, as well as routine tissue homeostasis. This process involves the induction of programmed cell death in specific cells within the tissues and the specific recognition and removal of dying cells by a clearance 'crew' composed of professional, non-professional and specialized phagocytes. In the past few years, considerable progress has been made in identifying many features of apoptotic cell clearance. Some of these new observations challenge the way dying cells themselves are viewed, as well as how healthy cells interact with and respond to dying cells. Here we focus on the homeostatic removal of apoptotic cells in tissues.
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125
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Dysfunctional High-Density Lipoprotein: An Innovative Target for Proteomics and Lipidomics. CHOLESTEROL 2015; 2015:296417. [PMID: 26634153 PMCID: PMC4655037 DOI: 10.1155/2015/296417] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 10/12/2015] [Accepted: 10/12/2015] [Indexed: 02/02/2023]
Abstract
High-Density Lipoprotein-Cholesterol (HDL-C) is regarded as an important protective factor against cardiovascular disease, with abundant evidence of an inverse relationship between its serum levels and risk of cardiovascular disease, as well as various antiatherogenic, antioxidant, and anti-inflammatory properties. Nevertheless, observations of hereditary syndromes featuring scant HDL-C concentration in absence of premature atherosclerotic disease suggest HDL-C levels may not be the best predictor of cardiovascular disease. Indeed, the beneficial effects of HDL may not depend solely on their concentration, but also on their quality. Distinct subfractions of this lipoprotein appear to be constituted by specific protein-lipid conglomerates necessary for different physiologic and pathophysiologic functions. However, in a chronic inflammatory microenvironment, diverse components of the HDL proteome and lipid core suffer alterations, which propel a shift towards a dysfunctional state, where HDL-C becomes proatherogenic, prooxidant, and proinflammatory. This heterogeneity highlights the need for further specialized molecular studies in this aspect, in order to achieve a better understanding of this dysfunctional state; with an emphasis on the potential role for proteomics and lipidomics as valuable methods in the search of novel therapeutic approaches for cardiovascular disease.
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Tang C, Liu Y, Yang W, Storey C, McMillen TS, Houston BA, Heinecke JW, LeBoeuf RC. Hematopoietic ABCA1 deletion promotes monocytosis and worsens diet-induced insulin resistance in mice. J Lipid Res 2015; 57:100-8. [PMID: 26531812 DOI: 10.1194/jlr.m064303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Indexed: 12/20/2022] Open
Abstract
Low-grade chronic inflammation plays an important role in the pathogenesis of obesity-induced insulin resistance. ABCA1 is essential for reverse cholesterol transport and HDL synthesis, and protects against macrophage inflammation. In the present study, the effects of ABCA1 deficiency in hematopoietic cells on diet-induced inflammation and insulin resistance were tested in vivo using bone marrow transplanted (BMT)-WT and BMT-ABCA1(-/-) mice. When challenged with a high-fat high-carbohydrate diabetogenic diet with added cholesterol (HFHSC), BMT-ABCA1(-/-) mice displayed enhanced insulin resistance and impaired glucose tolerance as compared with BMT-WT mice. The worsened insulin resistance and impaired glucose tolerance in BMT-ABCA1(-/-) mice were accompanied by increased macrophage accumulation and inflammation in adipose tissue and liver. Moreover, BMT-ABCA1(-/-) mice had significantly higher hematopoietic stem cell proliferation, myeloid cell expansion, and monocytosis when challenged with the HFHSC diet. In vitro studies indicated that macrophages from ABCA1(-/-) mice showed significantly increased inflammatory responses induced by saturated fatty acids. Taken together, these studies point to an important role for hematopoietic ABCA1 in modulating a feed-forward mechanism in obesity such that inflamed tissue macrophages stimulate the production of more monocytes, leading to an exacerbation of inflammation and associated disease processes.
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Affiliation(s)
- Chongren Tang
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
| | - Yuhua Liu
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
| | - Wendy Yang
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
| | - Carl Storey
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
| | - Tim S McMillen
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
| | - Barbara A Houston
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
| | - Jay W Heinecke
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
| | - Renee C LeBoeuf
- Diabetes Obesity Center for Excellence, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109
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Jeon BH, Lee YH, Yun MR, Kim SH, Lee BW, Kang ES, Lee HC, Cha BS. Increased expression of ATP-binding cassette transporter A1 (ABCA1) as a possible mechanism for the protective effect of cilostazol against hepatic steatosis. Metabolism 2015; 64:1444-53. [PMID: 26362727 DOI: 10.1016/j.metabol.2015.07.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/24/2015] [Accepted: 07/15/2015] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Cilostazol, a phosphodiesterase 3, has been widely used in patients with arterial disease and is known to have additional beneficial effects on dyslipidemia. However, the effect of cilostazol on hepatic steatosis has not been fully elucidated. We investigated the effect of cilostazol on hepatic ABCA1 expression and hepatic steatosis in diet-induced obesity mice model. METHODS Hepatic ABCA1 expression and lipid accumulation were analyzed in HepG2 cell lines treated with cilostazol. Male C57BL/6 mice were randomly divided into three groups: (1) fed normal chow diet with vehicle; (2) fed high-fat diet (HFD) with vehicle; (3) fed HFD with cilostazol. Cilostazol (30 mg/kg) was orally administered once daily for 9 weeks. RESULTS Cilostazol significantly enhanced ABCA1 expression and restored ABCA1 expression reduced by palmitate in HepG2 cells. Cilostazol treatment ameliorated lipid accumulation induced by palmitate, and this effect was diminished when ABCA1 or LRP1 was silenced by small interference RNA. After silencing of LRP1, ABCA1 expression was decreased in HepG2 cells. Cilostazol significantly enhanced hepatic ABCA1 expression and decreased hepatic fat in HFD-fed mice. Hepatic expression of cleaved caspase-3 and PARP1 was also decreased in HFD-fed mice treated with cilostazol. CONCLUSIONS Cilostazol ameliorated hepatic steatosis and increased ABCA1 expression in the hepatocytes. Enhancing ABCA1 expression with cilostazol represents a potential therapeutic avenue for treatment of hepatic steatosis.
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Affiliation(s)
- Byung Hun Jeon
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Yong-ho Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Mi Ra Yun
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Soo Hyun Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Byung Wan Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Eun Seok Kang
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Hyun Chul Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Bong-Soo Cha
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea; Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
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Yamauchi Y, Yokoyama S, Chang TY. ABCA1-dependent sterol release: sterol molecule specificity and potential membrane domain for HDL biogenesis. J Lipid Res 2015; 57:77-88. [PMID: 26497474 DOI: 10.1194/jlr.m063784] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 01/28/2023] Open
Abstract
Mammalian cells synthesize various sterol molecules, including the C30 sterol, lanosterol, as cholesterol precursors in the endoplasmic reticulum. The build-up of precursor sterols, including lanosterol, displays cellular toxicity. Precursor sterols are found in plasma HDL. How these structurally different sterols are released from cells is poorly understood. Here, we show that newly synthesized precursor sterols arriving at the plasma membrane (PM) are removed by extracellular apoA-I in a manner dependent on ABCA1, a key macromolecule for HDL biogenesis. Analysis of sterol molecules by GC-MS and tracing the fate of radiolabeled acetate-derived sterols in normal and mutant Niemann-Pick type C cells reveal that ABCA1 prefers newly synthesized sterols, especially lanosterol, as the substrates before they are internalized from the PM. We also show that ABCA1 resides in a cholesterol-rich membrane domain resistant to the mild detergent, Brij 98. Blocking ACAT activity increases the cholesterol contents of this domain. Newly synthesized C29/C30 sterols are transiently enriched within this domain, but rapidly disappear from this domain with a half-life of less than 1 h. Our work shows that substantial amounts of precursor sterols are transported to a certain PM domain and are removed by the ABCA1-dependent pathway.
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Affiliation(s)
- Yoshio Yamauchi
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Shinji Yokoyama
- Nutritional Health Science Research Center and Department of Food and Nutritional Sciences, Chubu University, Kasugai 487-8501, Japan
| | - Ta-Yuan Chang
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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129
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Abstract
PURPOSE OF REVIEW Randomized clinical trials provide strong evidence that pharmacological elevation of HDL-cholesterol (HDL-C) fails to reduce cardiovascular disease (CVD) risk in statin-treated humans. It is thus critical to identify new metrics that capture HDL's cardioprotective effects. RECENT FINDINGS We review recent evidence that HDL's cholesterol efflux capacity is a strong inverse predictor of incident and prevalent CVD in humans. In light of those findings, we assess the proposal that impaired macrophage cholesterol efflux to HDL contributes to disease risk. We also discuss recent studies implicating small HDL particles in cholesterol efflux from macrophages. SUMMARY These observations lay the foundation for a new approach to understanding mechanistically how HDL's functional properties help reduce CVD risk.
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Affiliation(s)
- Patrick M Hutchins
- Department of Medicine, University of Washington, Seattle, Washington, USA
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130
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Marcantoni E, Dovizio M, O′Gaora P, Di Francesco L, Bendaya I, Schiavone S, Trenti A, Guillem-Llobat P, Zambon A, Nardelli GB, Trevisi L, Patrignani P, Belton O. Dysregulation of gene expression in human fetal endothelial cells from gestational diabetes in response to TGF-β1. Prostaglandins Other Lipid Mediat 2015; 120:103-14. [DOI: 10.1016/j.prostaglandins.2015.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/11/2015] [Accepted: 03/16/2015] [Indexed: 11/24/2022]
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131
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Shao B, de Boer I, Tang C, Mayer PS, Zelnick L, Afkarian M, Heinecke JW, Himmelfarb J. A Cluster of Proteins Implicated in Kidney Disease Is Increased in High-Density Lipoprotein Isolated from Hemodialysis Subjects. J Proteome Res 2015; 14:2792-806. [PMID: 26011469 DOI: 10.1021/acs.jproteome.5b00060] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cardiovascular disease is the leading cause of death in end-stage renal disease (ESRD) patients treated with hemodialysis. An important contributor might be a decline in the cardioprotective effects of high-density lipoprotein (HDL). One important factor affecting HDL's cardioprotective properties may involve the alterations of protein composition in HDL. In the current study, we used complementary proteomics approaches to detect and quantify relative levels of proteins in HDL isolated from control and ESRD subjects. Shotgun proteomics analysis of HDL isolated from 20 control and 40 ESRD subjects identified 63 proteins in HDL. Targeted quantitative proteomics by isotope-dilution selective reaction monitoring revealed that 22 proteins were significantly enriched and 6 proteins were significantly decreased in ESRD patients. Strikingly, six proteins implicated in renal disease, including B2M, CST3, and PTGDS, were markedly increased in HDL of uremic subjects. Moreover, several of these proteins (SAA1, apoC-III, PON1, etc.) have been associated with atherosclerosis. Our observations indicate that the HDL proteome is extensively remodeled in uremic subjects. Alterations of the protein cargo of HDL might impact HDL's proposed cardioprotective properties. Quantifying proteins in HDL may be useful in the assessment of cardiovascular risk in patients with ESRD and in assessing response to therapeutic interventions.
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Affiliation(s)
- Baohai Shao
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
| | - Ian de Boer
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
| | - Chongren Tang
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
| | - Philip S Mayer
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
| | - Leila Zelnick
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
| | - Maryam Afkarian
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
| | - Jay W Heinecke
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
| | - Jonathan Himmelfarb
- †Diabetes and Obesity Center of Excellence and ‡Kidney Research Institute, Department of Medicine, University of Washington, 850 Republican Street, Seattle, Washington 98195, United States
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132
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Fond AM, Lee CS, Schulman IG, Kiss RS, Ravichandran KS. Apoptotic cells trigger a membrane-initiated pathway to increase ABCA1. J Clin Invest 2015; 125:2748-58. [PMID: 26075824 DOI: 10.1172/jci80300] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 05/12/2015] [Indexed: 01/15/2023] Open
Abstract
Macrophages clear millions of apoptotic cells daily and, during this process, take up large quantities of cholesterol. The membrane transporter ABCA1 is a key player in cholesterol efflux from macrophages and has been shown via human genetic studies to provide protection against cardiovascular disease. How the apoptotic cell clearance process is linked to macrophage ABCA1 expression is not known. Here, we identified a plasma membrane-initiated signaling pathway that drives a rapid upregulation of ABCA1 mRNA and protein. This pathway involves the phagocytic receptor brain-specific angiogenesis inhibitor 1 (BAI1), which recognizes phosphatidylserine on apoptotic cells, and the intracellular signaling intermediates engulfment cell motility 1 (ELMO1) and Rac1, as ABCA1 induction was attenuated in primary macrophages from mice lacking these molecules. Moreover, this apoptotic cell-initiated pathway functioned independently of the liver X receptor (LXR) sterol-sensing machinery that is known to regulate ABCA1 expression and cholesterol efflux. When placed on a high-fat diet, mice lacking BAI1 had increased numbers of apoptotic cells in their aortic roots, which correlated with altered lipid profiles. In contrast, macrophages from engineered mice with transgenic BAI1 overexpression showed greater ABCA1 induction in response to apoptotic cells compared with those from control animals. Collectively, these data identify a membrane-initiated pathway that is triggered by apoptotic cells to enhance ABCA1 within engulfing phagocytes and with functional consequences in vivo.
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133
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Louros NN, Tsiolaki PL, Griffin MDW, Howlett GJ, Hamodrakas SJ, Iconomidou VA. Chameleon 'aggregation-prone' segments of apoA-I: A model of amyloid fibrils formed in apoA-I amyloidosis. Int J Biol Macromol 2015; 79:711-8. [PMID: 26049118 DOI: 10.1016/j.ijbiomac.2015.05.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/20/2015] [Accepted: 05/22/2015] [Indexed: 11/18/2022]
Abstract
Apolipoprotein A-I (apoA-I) is the major component of high density lipoproteins and plays a vital role in reverse cholesterol transport. Lipid-free apoA-I is the main constituent of amyloid deposits found in atherosclerotic plaques, an acquired type of amyloidosis, whereas its N-terminal fragments have been associated with a hereditary form, known as familial apoA-I amyloidosis. Here, we identified and verified four "aggregation-prone" segments of apoA-I with amyloidogenic properties, utilizing electron microscopy, X-ray fiber diffraction, ATR FT-IR spectroscopy and polarized light microscopy. These segments may act as conformational switches, possibly controlling the transition of the α-helical apoA-I content into the "cross-β" architecture of amyloid fibrils. A structural model illuminating the structure of amyloid fibrils formed by the N-terminal fragments of apoA-I is proposed, indicating that two of the identified chameleon segments may play a vital part in the formation of amyloid fibrils in familial apoA-I amyloidosis.
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Affiliation(s)
- Nikolaos N Louros
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | - Paraskevi L Tsiolaki
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Geoffrey J Howlett
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Stavros J Hamodrakas
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | - Vassiliki A Iconomidou
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece.
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134
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Abstract
Cholesterol is an essential component for neuronal physiology not only during development stage but also in the adult life. Cholesterol metabolism in brain is independent from that in peripheral tissues due to blood-brain barrier. The content of cholesterol in brain must be accurately maintained in order to keep brain function well. Defects in brain cholesterol metabolism has been shown to be implicated in neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), and some cognitive deficits typical of the old age. The brain contains large amount of cholesterol, but the cholesterol metabolism and its complex homeostasis regulation are currently poorly understood. This review will seek to integrate current knowledge about the brain cholesterol metabolism with molecular mechanisms.
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Affiliation(s)
- Juan Zhang
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China, Hefei, 230026 China
| | - Qiang Liu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China, Hefei, 230026 China
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135
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ABCA1 expression in macrophages of allogeneic hematopoietic stem cell transplantation patients with severe infection undergoing continuous blood purification. Int J Artif Organs 2015; 38:83-8. [PMID: 25744199 DOI: 10.5301/ijao.5000388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2015] [Indexed: 11/20/2022]
Abstract
BACKGROUND Excessive activation of the inflammatory mediator cascade after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients is associated with high mortality. Many studies have shown that continuous blood purification (CBP) could improve the prognosis of allo-HSCT patients with severe infection. However, the exact mechanism remains unclear. The aim of this study was to observe the effect of CBP on the expression of ATP-binding cassette transporter A1 (ABCA1) in macrophages, and to investigate the interventional effects of CBP on serum cytokine in allo-HSCT patients with severe infection. METHODS A total of 26 allo-HSCT patients with severe infection were included in this study. Before CBP and after CBP, blood samples were collected to observe hepatic and renal function, and the serum levels of TNF-α, IL-1, IL-6, and IL-10 were detected via ELISA. The THP-1 macrophages were exposed to serum samples obtained from patients at specific time points during CBP to test the changes of ABCA1 in macrophages by real-timePCR and Western blotting. RESULTS Serum creatinine, alanine aminotransferase, and C reaction protein (CRP) levels decreased significantly after CBP. Moreover, TNF-α, IL-1, and IL-6 serum levels decreased significantly, but IL-10 level increased significantly after CBP (P<.05). After CBP, ABCA1 expression levels were higher than those before CBP, and ABCA1 expression was significantly increased with the supplementation of CBP (P<.05). CONCLUSIONS CBP improved the condition of allo-HSCT patients with severe infection. CBP may be a potent up-regulator of the ABCA1 levels in macrophages of allo-HSCT patients with severe infection.
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136
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Diosgenin inhibits atherosclerosis via suppressing the MiR-19b-induced downregulation of ATP-binding cassette transporter A1. Atherosclerosis 2015; 240:80-9. [PMID: 25765596 DOI: 10.1016/j.atherosclerosis.2015.02.044] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/02/2015] [Accepted: 02/23/2015] [Indexed: 12/20/2022]
Abstract
RATIONALE Diosgenin (Dgn), a structural analogue of cholesterol, has been reported to have the hypolipidemic and antiatherogenic properties, but the underlying mechanisms are not fully understood. Given the key roles of macrophages in cholesterol metabolism and atherogenesis, it is critical to investigate macrophage cholesterol efflux and development of atherosclerotic lesion after Dgn treatment. OBJECTIVE This study was designed to evaluate the potential effects of Dgn on macrophage cholesterol metabolism and the development of aortic atherosclerosis, and to explore its underlying mechanisms. METHODS AND RESULTS Dgn significantly up-regulated the expression of ATP-binding cassette transporter A1 (ABCA1) protein, but didn't affect liver X receptor α levels in foam cells derived from human THP-1 macrophages and mouse peritoneal macrophages (MPMs) as determined by western blotting. The miR-19b levels were markedly down-regulated in Dgn-treated THP-1 macrophages/MPM-derived foam cells. Cholesterol transport assays revealed that treatment with Dgn alone or together with miR-19b inhibitor notably enhanced ABCA1-dependent cholesterol efflux, resulting in the reduced levels of total cholesterol, free cholesterol and cholesterol ester as determined by high-performance liquid chromatography. The fecal 3H-sterol originating from cholesterol-laden MPMs was increased in apolipoprotein E knockout mice treated with Dgn or both Dgn and antagomiR-19b. Treatment with Dgn alone or together with antagomiR-19b elevated plasma high-density lipoprotein levels, but reduced plasma low-density lipoprotein levels. Accordingly, aortic lipid deposition and plaque area were reduced, and collagen content and ABCA1 expression were increased in mice treated with Dgn alone or together with antagomiR-19b. However, miR-19b overexpression abrogated the lipid-lowering and atheroprotective effects induced by Dgn. CONCLUSION The present study demonstrates that Dgn enhances ABCA1-dependent cholesterol efflux and inhibits aortic atherosclerosis progression by suppressing macrophage miR-19b expression.
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137
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Dubland JA, Francis GA. Lysosomal acid lipase: at the crossroads of normal and atherogenic cholesterol metabolism. Front Cell Dev Biol 2015; 3:3. [PMID: 25699256 PMCID: PMC4313778 DOI: 10.3389/fcell.2015.00003] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/07/2015] [Indexed: 01/01/2023] Open
Abstract
Unregulated cellular uptake of apolipoprotein B-containing lipoproteins in the arterial intima leads to the formation of foam cells in atherosclerosis. Lysosomal acid lipase (LAL) plays a crucial role in both lipoprotein lipid catabolism and excess lipid accumulation as it is the primary enzyme that hydrolyzes cholesteryl esters derived from both low density lipoprotein (LDL) and modified forms of LDL. Evidence suggests that as atherosclerosis progresses, accumulation of excess free cholesterol in lysosomes leads to impairment of LAL activity, resulting in accumulation of cholesteryl esters in the lysosome as well as the cytosol in foam cells. Impaired metabolism and release of cholesterol from lysosomes can lead to downstream defects in ATP-binding cassette transporter A1 regulation, needed to offload excess cholesterol from plaque foam cells. This review focuses on the role LAL plays in normal cholesterol metabolism and how the associated changes in its enzymatic activity may ultimately contribute to atherosclerosis progression.
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Affiliation(s)
- Joshua A Dubland
- Department of Medicine, Centre for Heart Lung Innovation, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia Vancouver, BC, Canada
| | - Gordon A Francis
- Department of Medicine, Centre for Heart Lung Innovation, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia Vancouver, BC, Canada
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138
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Du XM, Kim MJ, Hou L, Le Goff W, Chapman MJ, Van Eck M, Curtiss LK, Burnett JR, Cartland SP, Quinn CM, Kockx M, Kontush A, Rye KA, Kritharides L, Jessup W. HDL particle size is a critical determinant of ABCA1-mediated macrophage cellular cholesterol export. Circ Res 2015; 116:1133-42. [PMID: 25589556 DOI: 10.1161/circresaha.116.305485] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE High-density lipoprotein (HDL) is a heterogeneous population of particles. Differences in the capacities of HDL subfractions to remove cellular cholesterol may explain variable correlations between HDL-cholesterol and cardiovascular risk and inform future targets for HDL-related therapies. The ATP binding cassette transporter A1 (ABCA1) facilitates cholesterol efflux to lipid-free apolipoprotein A-I, but the majority of apolipoprotein A-I in the circulation is transported in a lipidated state and ABCA1-dependent efflux to individual HDL subfractions has not been systematically studied. OBJECTIVE Our aims were to determine which HDL particle subfractions are most efficient in mediating cellular cholesterol efflux from foam cell macrophages and to identify the cellular cholesterol transporters involved in this process. METHODS AND RESULTS We used reconstituted HDL particles of defined size and composition, isolated subfractions of human plasma HDL, cell lines stably expressing ABCA1 or ABCG1, and both mouse and human macrophages in which ABCA1 or ABCG1 expression was deleted. We show that ABCA1 is the major mediator of macrophage cholesterol efflux to HDL, demonstrating most marked efficiency with small, dense HDL subfractions (HDL3b and HDL3c). ABCG1 has a lesser role in cholesterol efflux and a negligible role in efflux to HDL3b and HDL3c subfractions. CONCLUSIONS Small, dense HDL subfractions are the most efficient mediators of cholesterol efflux, and ABCA1 mediates cholesterol efflux to small dense HDL and to lipid-free apolipoprotein A-I. HDL-directed therapies should target increasing the concentrations or the cholesterol efflux capacity of small, dense HDL species in vivo.
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Affiliation(s)
- Xian-Ming Du
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Mi-Jurng Kim
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Liming Hou
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Wilfried Le Goff
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - M John Chapman
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Miranda Van Eck
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Linda K Curtiss
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - John R Burnett
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Sian P Cartland
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Carmel M Quinn
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Maaike Kockx
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Anatol Kontush
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Kerry-Anne Rye
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Leonard Kritharides
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.)
| | - Wendy Jessup
- From the Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia (X.-M.D., M.-J.K., L.H., S.P.C., C.M.Q., K.-A.R); INSERM, UMR_1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Pitié-Salpétrière University Hospital, Paris, France (W.L.G., M.J.C., A.K.); Université Pierre et Marie Curie-Paris 6, Paris, France (W.L.G., M.J.C., A.K.); Division of Biopharmaceutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands (M.V.E.); Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA (L.K.C.); Department of Clinical Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia (J.R.B.); School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia (J.R.B.); Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia (M.K., L.K., W.J.); and Department of Cardiology, Concord Hospital, Sydney, New South Wales, Australia (L.K.).
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139
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Abstract
During development, stress, infection, or normal homeostasis, billions of cells die on a daily basis, and the responsibility of clearing these cellular corpses lies with the phagocytes of innate immune system. This process, termed efferocytosis , is critical for the prevention of inflammation and autoimmunity , as well as modulation of the adaptive immune response. Defective clearance of dead cells is characteristic of many human autoimmune or autoinflammatory disorders, such as systemic lupus erythematosus (SLE), atherosclerosis, and diabetes. The mechanisms that phagocytes employ to sense, engulf, and process dead cells for an appropriate immune response have been an area of great interest. However, insight into novel mechanisms of programmed cell death , such as necroptosis, has shed light on the fact that while the diner (or phagocyte) is important, the meal itself (the type of dead cell) can play a crucial role in shaping the pursuant immune response.
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Affiliation(s)
- Jennifer Martinez
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
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140
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Wang X, Cao K, Sun X, Chen Y, Duan Z, Sun L, Guo L, Bai P, Sun D, Fan J, He X, Young W, Ren Y. Macrophages in spinal cord injury: phenotypic and functional change from exposure to myelin debris. Glia 2014; 63:635-51. [PMID: 25452166 DOI: 10.1002/glia.22774] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 11/05/2014] [Accepted: 11/12/2014] [Indexed: 01/14/2023]
Abstract
Macrophage activation and persistent inflammation contribute to the pathological process of spinal cord injury (SCI). It was reported that M2 macrophages were induced at 3-7 days after SCI but M2 markers were reduced or eliminated after 1 week. By contrast, M1 macrophage response is rapidly induced and then maintained at injured spinal cord. However, factors that modulate macrophage phenotype and function are poorly understood. We developed a model to distinguish bone-marrow derived macrophages (BMDMs) from residential microglia and explored how BMDMs change their phenotype and functions in response to the lesion-related factors in injured spinal cord. Infiltrating BMDMs expressing higher Mac-2 and lower CX3CR1 migrate to the epicenter of injury, while microglia expressing lower Mac-2 but higher CX3CR1 distribute to the edges of lesion. Myelin debris at the lesion site switches BMDMs from M2 phenotype towards M1-like phenotype. Myelin debris activates ATP-binding cassette transporter A1 (ABCA1) for cholesterol efflux in response to myelin debris loading in vitro. However, this homeostatic mechanism in injured site is overwhelmed, leading to the development of foamy macrophages and lipid plaque in the lesion site. The persistence of these cells indicates a pro-inflammatory environment, associated with enhanced neurotoxicity and impaired wound healing. These foamy macrophages have poor capacity to phagocytose apoptotic neutrophils resulting in uningested neutrophils releasing their toxic contents and further tissue damage. In conclusion, these data demonstrate for the first time that myelin debris generated in injured spinal cord modulates macrophage activation. Lipid accumulation following macrophage phenotype switch contributes to SCI pathology.
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Affiliation(s)
- Xi Wang
- W. M. Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey, New Jersey; Institute of Neurosciences, the Fourth Military Medical University, Xian, China
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141
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Campos-Bedolla P, Walter FR, Veszelka S, Deli MA. Role of the Blood–Brain Barrier in the Nutrition of the Central Nervous System. Arch Med Res 2014; 45:610-38. [DOI: 10.1016/j.arcmed.2014.11.018] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 11/24/2014] [Indexed: 12/22/2022]
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142
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Taylor JMW, Allen AM, Graham A. Targeting mitochondrial 18 kDa translocator protein (TSPO) regulates macrophage cholesterol efflux and lipid phenotype. Clin Sci (Lond) 2014; 127:603-13. [PMID: 24814875 DOI: 10.1042/cs20140047] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The aim of the present study was to establish mitochondrial cholesterol trafficking 18 kDa translocator protein (TSPO) as a potential therapeutic target, capable of increasing macrophage cholesterol efflux to (apo)lipoprotein acceptors. Expression and activity of TSPO in human (THP-1) macrophages were manipulated genetically and by the use of selective TSPO ligands. Cellular responses were analysed by quantitative PCR (Q-PCR), immunoblotting and radiolabelling, including [3H]cholesterol efflux to (apo)lipoprotein A-I (apoA-I), high-density lipoprotein (HDL) and human serum. Induction of macrophage cholesterol deposition by acetylated low-density lipoprotein (AcLDL) increased expression of TSPO mRNA and protein, reflecting findings in human carotid atherosclerosis. Transient overexpression of TSPO enhanced efflux (E%) of [3H]cholesterol to apoA-I, HDL and human serum compared with empty vector (EV) controls, whereas gene knockdown of TSPO achieved the converse. Ligation of TSPO (using PK11195, FGIN-1-27 and flunitrazepam) triggered increases in [3H]cholesterol efflux, an effect that was amplified in TSPO-overexpressing macrophages. Overexpression of TSPO induced the expression of genes [PPARA (peroxisome-proliferator-activated receptor α), NR1H3 (nuclear receptor 1H3/liver X receptor α), ABCA1 (ATP-binding cassette A1), ABCG4 (ATP-binding cassette G4) and APOE (apolipoprotein E)] and proteins (ABCA1 and PPARα) involved in cholesterol efflux, reduced macrophage neutral lipid mass and lipogenesis and limited cholesterol esterification following exposure to AcLDL. Thus, targeting TSPO reduces macrophage lipid content and prevents macrophage foam cell formation, via enhanced cholesterol efflux to (apo)lipoprotein acceptors.
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Affiliation(s)
- Janice M W Taylor
- *Department of Life Sciences and the Diabetes Research Group, Institute for Applied Health Research, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, U.K
| | - Anne-Marie Allen
- *Department of Life Sciences and the Diabetes Research Group, Institute for Applied Health Research, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, U.K
| | - Annette Graham
- *Department of Life Sciences and the Diabetes Research Group, Institute for Applied Health Research, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, U.K
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143
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Nambiar SS, Shetty NP. Antioxidant and Atherogenic Foam cell Prevention Ability of Methanol and Aqueous Extract of E
mblica Officinalis
Fruits and Its Effect on CD36
and ABCA1
Gene Expression in RAW 264.7 Macrophage Cell Line. J Food Biochem 2014. [DOI: 10.1111/jfbc.12089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sinjitha S. Nambiar
- Plant Cell Biotechnology Department; CSIR - Central Food Technological Research Institute (CFTRI); Mysore 570 020 India
| | - Nandini Prasad Shetty
- Plant Cell Biotechnology Department; CSIR - Central Food Technological Research Institute (CFTRI); Mysore 570 020 India
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144
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Liu L, Zhang M, Li L, Li C, Min X, Zheng M. Expression and clinical significance of ATP-binding cassette transporter 1 in serum and placental tissue in Chinese patients with preeclampsia. Gynecol Obstet Invest 2014; 78:194-200. [PMID: 25139615 DOI: 10.1159/000362551] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 03/24/2014] [Indexed: 11/19/2022]
Abstract
AIM To investigate the expression and clinical significance of ATP-binding cassette transporter 1 (ABCA1) in pregnant women with preeclampsia (PE). METHODS 52 pregnant women with PE who were admitted for delivery were enrolled in the study, while 30 normal pregnant inpatients were chosen as controls. Blood lipid and serum ABCA1 concentrations were assayed by enzymatic analysis and ELISA, respectively, and the expression of the ABCA1 gene and its encoded protein were detected and quantified by RT-PCR and Western blotting. RESULTS In the study group, blood lipid levels were significantly higher than those in the control group (p < 0.01), while the ABCA1 gene and its encoded protein expression in both serum and placental tissue were lower than that of controls. These differences were highly correlated with disease severity (p < 0.05). In PE patients, serum ABCA1 concentration was positively correlated with ABCA1 protein expression in placental tissue (r = 0.384, p < 0.01) and high-density lipoprotein level (r = 0.318, p < 0.05), but negatively correlated with low-density lipoprotein level (r = -0.279, p < 0.05). CONCLUSION In PE women, expression of ABCA1 was decreased, suggesting that ABCA1 may play an important role in onset of PE by altering blood lipid metabolism.
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Affiliation(s)
- Lixing Liu
- Department of Anatomy, Fujian Medical University, Fuzhou, China
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145
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Hottman DA, Chernick D, Cheng S, Wang Z, Li L. HDL and cognition in neurodegenerative disorders. Neurobiol Dis 2014; 72 Pt A:22-36. [PMID: 25131449 DOI: 10.1016/j.nbd.2014.07.015] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 06/26/2014] [Accepted: 07/28/2014] [Indexed: 12/12/2022] Open
Abstract
High-density lipoproteins (HDLs) are a heterogeneous group of lipoproteins composed of various lipids and proteins. HDL is formed both in the systemic circulation and in the brain. In addition to being a crucial player in the reverse cholesterol transport pathway, HDL possesses a wide range of other functions including anti-oxidation, anti-inflammation, pro-endothelial function, anti-thrombosis, and modulation of immune function. It has been firmly established that high plasma levels of HDL protect against cardiovascular disease. Accumulating evidence indicates that the beneficial role of HDL extends to many other systems including the central nervous system. Cognition is a complex brain function that includes all aspects of perception, thought, and memory. Cognitive function often declines during aging and this decline manifests as cognitive impairment/dementia in age-related and progressive neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. A growing concern is that no effective therapy is currently available to prevent or treat these devastating diseases. Emerging evidence suggests that HDL may play a pivotal role in preserving cognitive function under normal and pathological conditions. This review attempts to summarize recent genetic, clinical and experimental evidence for the impact of HDL on cognition in aging and in neurodegenerative disorders as well as the potential of HDL-enhancing approaches to improve cognitive function.
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Affiliation(s)
- David A Hottman
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Dustin Chernick
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Shaowu Cheng
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Zhe Wang
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Ling Li
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA; Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA.
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146
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Ma D, Liu W, Wang Y. ApoA-I or ABCA1 expression suppresses fatty acid synthesis by reducing 27-hydroxycholesterol levels. Biochimie 2014; 103:101-8. [DOI: 10.1016/j.biochi.2014.04.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 04/22/2014] [Indexed: 11/29/2022]
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147
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Zhou C, Chen J, Zhang X, Costa LG, Guizzetti M. Prenatal Ethanol Exposure Up-Regulates the Cholesterol Transporters ATP-Binding Cassette A1 and G1 and Reduces Cholesterol Levels in the Developing Rat Brain. Alcohol Alcohol 2014; 49:626-34. [PMID: 25081040 DOI: 10.1093/alcalc/agu049] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 06/17/2014] [Indexed: 01/24/2023] Open
Abstract
AIMS Cholesterol plays a pivotal role in many aspects of brain development; reduced cholesterol levels during brain development, as a consequence of genetic defects in cholesterol biosynthesis, leads to severe brain damage, including microcephaly and mental retardation, both of which are also hallmarks of the fetal alcohol syndrome. We had previously shown that ethanol up-regulates the levels of two cholesterol transporters, ABCA1 (ATP binding cassette-A1) and ABCG1, leading to increased cholesterol efflux and decreased cholesterol content in astrocytes in vitro. In the present study we investigated whether similar effects could be seen in vivo. METHODS Pregnant Sprague-Dawley rats were fed liquid diets containing 36% of the calories from ethanol from gestational day (GD) 6 to GD 21. A pair-fed control groups and an ad libitum control group were included in the study. ABCA1 and ABCG1 protein expression and cholesterol and phospholipid levels were measured in the neocortex of female and male fetuses at GD 21. RESULTS Body weights were decreased in female fetuses as a consequence of ethanol treatments. ABCA1 and ABCG1 protein levels were increased, and cholesterol levels were decreased, in the neocortex of ethanol-exposed female, but not male, fetuses. Levels of phospholipids were unchanged. Control female fetuses fed ad libitum displayed an up-regulation of ABCA1 and a decrease in cholesterol content compared with pair-fed controls, suggesting that a compensatory up-regulation of cholesterol levels may occur during food restriction. CONCLUSION Maternal ethanol consumption may affect fetal brain development by increasing cholesterol transporters' expression and reducing brain cholesterol levels.
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Affiliation(s)
- Chunyan Zhou
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Jing Chen
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Xiaolu Zhang
- Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Jesse Brown VA Medical Center, Chicago, IL, USA
| | - Lucio G Costa
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA Department of Neuroscience, University of Parma, Parma, Italy
| | - Marina Guizzetti
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Jesse Brown VA Medical Center, Chicago, IL, USA
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148
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Abstract
Most types of cells in the body do not express the capability of catabolizing cholesterol, so cholesterol efflux is essential for homeostasis. For instance, macrophages possess four pathways for exporting free (unesterified) cholesterol to extracellular high density lipoprotein (HDL). The passive processes include simple diffusion via the aqueous phase and facilitated diffusion mediated by scavenger receptor class B, type 1 (SR-BI). Active pathways are mediated by the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1, which are membrane lipid translocases. The efflux of cellular phospholipid and free cholesterol to apolipoprotein A-I promoted by ABCA1 is essential for HDL biogenesis. Current understanding of the molecular mechanisms involved in these four efflux pathways is presented in this minireview.
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Affiliation(s)
- Michael C Phillips
- From the Division of Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-5158
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149
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MicroRNA-19b promotes macrophage cholesterol accumulation and aortic atherosclerosis by targeting ATP-binding cassette transporter A1. Atherosclerosis 2014; 236:215-26. [PMID: 25084135 DOI: 10.1016/j.atherosclerosis.2014.07.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 06/19/2014] [Accepted: 07/07/2014] [Indexed: 12/20/2022]
Abstract
RATIONALE Macrophage accumulation of cholesterol leads to foam cell formation which is a major pathological event of atherosclerosis. Recent studies have shown that microRNA (miR)-19b might play an important role in cholesterol metabolism and atherosclerotic diseases. Here, we have identified miR-19b binding to the 3'UTR of ATP-binding cassette transporter A1 (ABCA1) transporters, and further determined the potential roles of this novel interaction in atherogenesis. OBJECTIVE To investigate the molecular mechanisms involved in a miR-19b promotion of macrophage cholesterol accumulation and the development of aortic atherosclerosis. METHODS AND RESULTS We performed bioinformatics analysis using online websites, and found that miR-19b was highly conserved during evolution and directly bound to ABCA1 mRNA with very low binding free energy. Luciferase reporter assay confirmed that miR-19b bound to 3110-3116 sites within ABCA1 3'UTR. MiR-19b directly regulated the expression levels of endogenous ABCA1 in foam cells derived from human THP-1 macrophages and mouse peritoneal macrophages (MPMs) as determined by qRT-PCR and western blot. Cholesterol transport assays revealed that miR-19b dramatically suppressed apolipoprotein AI-mediated ABCA1-dependent cholesterol efflux, resulting in the increased levels of total cholesterol (TC), free cholesterol (FC) and cholesterol ester (CE) as revealed by HPLC. The excretion of (3)H-cholesterol originating from cholesterol-laden MPMs into feces was decreased in mice overexpressing miR-19b. Finally, we evaluated the proatherosclerotic role of miR-19b in apolipoprotein E deficient (apoE(-/-)) mice. Treatment with miR-19b precursor reduced plasma high-density lipoprotein (HDL) levels, but increased plasma low-density lipoprotein (LDL) levels. Consistently, miR-19b precursor treatment increased aortic plaque size and lipid content, but reduced collagen content and ABCA1 expression. In contrast, treatment with the inhibitory miR-19b antisense oligonucleotides (ASO) prevented or reversed these effects. CONCLUSION MiR-19b promotes macrophage cholesterol accumulation, foam cell formation and aortic atherosclerotic development by targeting ABCA1.
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150
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Harrington JM, Nishanova T, Pena SR, Hess M, Scelsi CL, Widener J, Hajduk SL. A retained secretory signal peptide mediates high density lipoprotein (HDL) assembly and function of haptoglobin-related protein. J Biol Chem 2014; 289:24811-20. [PMID: 25037218 DOI: 10.1074/jbc.m114.567578] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Haptoglobin-related protein (Hpr) is a component of a minor subspecies of high density lipoproteins (HDL) that function in innate immunity. Here we show that assembly of Hpr into HDL is mediated by its retained N-terminal signal peptide, an unusual feature for a secreted protein and the major difference between Hpr and the soluble acute phase protein haptoglobin (Hp). The 18-amino acid signal peptide is necessary for binding to HDL and interacts directly with the hydrocarbon region of lipids. Utilizing model liposomes, we show that the rate of assembly and steady-state distribution of Hpr in lipid particles is mediated by the physical property of lipid fluidity. Dye release assays reveal that Hpr interacts more rapidly with fluid liposomes. Conversely, steady-state binding assays indicate that more rigid lipid compositions stabilize Hpr association. Lipid association also plays a role in facilitating hemoglobin binding by Hpr. Our data may offer an explanation for the distinct distribution of Hpr among HDL subspecies. Rather than protein-protein interactions mediating localization, direct interaction with phospholipids and sensitivity to lipid fluidity may be sufficient for localization of Hpr and may represent a mechanism of HDL subspeciation.
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Affiliation(s)
- John M Harrington
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Tuiumkan Nishanova
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Savannah Rose Pena
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Matthew Hess
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Chris L Scelsi
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Justin Widener
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Stephen L Hajduk
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
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