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Gómez Toledo A, Sorrentino JT, Sandoval DR, Malmström J, Lewis NE, Esko JD. A Systems View of the Heparan Sulfate Interactome. J Histochem Cytochem 2021; 69:105-119. [PMID: 33494649 PMCID: PMC7841697 DOI: 10.1369/0022155420988661] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/28/2022] Open
Abstract
Heparan sulfate proteoglycans consist of a small family of proteins decorated with one or more covalently attached heparan sulfate glycosaminoglycan chains. These chains have intricate structural patterns based on the position of sulfate groups and uronic acid epimers, which dictate their ability to engage a large repertoire of heparan sulfate-binding proteins, including extracellular matrix proteins, growth factors and morphogens, cytokines and chemokines, apolipoproteins and lipases, adhesion and growth factor receptors, and components of the complement and coagulation system. This review highlights recent progress in the characterization of the so-called "heparan sulfate interactome," with a major focus on systems-wide strategies as a tool for discovery and characterization of this subproteome. In addition, we compiled all heparan sulfate-binding proteins reported in the literature to date and grouped them into a few major functional classes by applying a networking approach.
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Affiliation(s)
- Alejandro Gómez Toledo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California
- Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, Lund, Sweden
| | - James T Sorrentino
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, California
- Department of Bioengineering, University of California, San Diego, La Jolla, California
| | - Daniel R Sandoval
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California
| | - Johan Malmström
- Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Nathan E Lewis
- Department of Bioengineering, University of California, San Diego, La Jolla, California
- Department of Pediatrics, University of California, San Diego, La Jolla, California
| | - Jeffrey D Esko
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California
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2
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Intrinsic and extrinsic regulation of cardiac lipoprotein lipase following diabetes. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:163-71. [PMID: 25463481 DOI: 10.1016/j.bbalip.2014.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 02/07/2023]
Abstract
Cardiac lipoprotein lipase (LPL) is a pivotal enzyme controlling heart metabolism by providing the majority of fatty acids required by this organ. From activation in cardiomyocytes to secretion to the vascular lumen, cardiac LPL is regulated by multiple pathways, which are altered during diabetes. Hence, dimerization/activation of LPL is modified following diabetes, a process controlled by lipase maturation factor 1. The role of AMP-activated protein kinase, protein kinase D, and heparan sulfate proteoglycans, intrinsic factors that regulate the intracellular transport of LPL is also shifted, and is discussed. More recent studies have identified several exogenous factors released from endothelial cells (EC) and adipose tissue that are required for proper functioning of LPL. In response to hyperglycemia, both active and latent heparanase are released from EC to facilitate LPL secretion. Diabetes also increased the expression of glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) in EC, which mediates the transport of LPL across EC. Angiopoietin-like protein 4 secreted from the adipose tissue has the potential to reduce coronary LPL activity. Knowledge of these intrinsic and extrinsic factors could be used develop therapeutic targets to normalize LPL function, and maintain cardiac energy homeostasis after diabetes.
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3
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Bouvy-Liivrand M, Heinäniemi M, John E, Schneider JG, Sauter T, Sinkkonen L. Combinatorial regulation of lipoprotein lipase by microRNAs during mouse adipogenesis. RNA Biol 2014; 11:76-91. [PMID: 24457907 PMCID: PMC3929427 DOI: 10.4161/rna.27655] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 12/20/2013] [Accepted: 12/23/2013] [Indexed: 11/19/2022] Open
Abstract
MicroRNAs (miRNAs) regulate gene expression directly through base pairing to their targets or indirectly through participating in multi-scale regulatory networks. Often miRNAs take part in feed-forward motifs where a miRNA and a transcription factor act on shared targets to achieve accurate regulation of processes such as cell differentiation. Here we show that the expression levels of miR-27a and miR-29a inversely correlate with the mRNA levels of lipoprotein lipase (Lpl), their predicted combinatorial target, and its key transcriptional regulator peroxisome proliferator-activated receptor gamma (Pparg) during 3T3-L1 adipocyte differentiation. More importantly, we show that Lpl, a key lipogenic enzyme, can be negatively regulated by the two miRNA families in a combinatorial fashion on the mRNA and functional level in maturing adipocytes. This regulation is mediated through the Lpl 3'UTR as confirmed by reporter gene assays. In addition, a small mathematical model captures the dynamics of this feed-forward motif and predicts the changes in Lpl mRNA levels upon network perturbations. The obtained results might offer an explanation to the dysregulation of LPL in diabetic conditions and could be extended to quantitative modeling of regulation of other metabolic genes under similar regulatory network motifs.
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Affiliation(s)
- Maria Bouvy-Liivrand
- Life Sciences Research Unit; University of Luxembourg; Luxembourg, Luxembourg
- Luxembourg Centre for Systems Biomedicine; University of Luxembourg; Esch-Sur-Alzette, Luxembourg
| | - Merja Heinäniemi
- Life Sciences Research Unit; University of Luxembourg; Luxembourg, Luxembourg
- Institute of Biomedicine; School of Medicine; University of Eastern Finland; Kuopio, Finland
| | - Elisabeth John
- Life Sciences Research Unit; University of Luxembourg; Luxembourg, Luxembourg
| | - Jochen G Schneider
- Luxembourg Centre for Systems Biomedicine; University of Luxembourg; Esch-Sur-Alzette, Luxembourg
- Saarland University Medical Center; Department of Medicine II; Homburg, Saar, Germany
| | - Thomas Sauter
- Life Sciences Research Unit; University of Luxembourg; Luxembourg, Luxembourg
| | - Lasse Sinkkonen
- Life Sciences Research Unit; University of Luxembourg; Luxembourg, Luxembourg
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4
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Tasdelen I, Berger R, Kalkhoven E. PPARγ regulates expression of carbohydrate sulfotransferase 11 (CHST11/C4ST1), a regulator of LPL cell surface binding. PLoS One 2013; 8:e64284. [PMID: 23696875 PMCID: PMC3655946 DOI: 10.1371/journal.pone.0064284] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 04/12/2013] [Indexed: 01/09/2023] Open
Abstract
The transcription factor PPARγ is the key regulator of adipocyte differentiation, function and maintenance, and the cellular target of the insulin-sensitizing thiazolidinediones. Identification and functional characterization of genes regulated by PPARγ will therefore lead to a better understanding of adipocyte biology and may also contribute to the development of new anti-diabetic drugs. Here, we report carbohydrate sulfotransferase 11 (Chst11/C4st1) as a novel PPARγ target gene. Chst11 can sulphate chondroitin, a major glycosaminoglycan involved in development and disease. The Chst11 gene contains two functional intronic PPARγ binding sites, and is up-regulated at the mRNA and protein level during 3T3-L1 adipogenesis. Chst11 knockdown reduced intracellular lipid accumulation in mature adipocytes, which is due to a lowered activity of lipoprotein lipase, which may associate with the adipocyte cell surface through Chst11-mediated sulfation of chondroitin, rather than impaired adipogenesis. Besides directly inducing Lpl expression, PPARγ may therefore control lipid accumulation by elevating the levels of Chst11-mediated proteoglycan sulfation and thereby increasing the binding capacity for Lpl on the adipocyte cell surface.
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Affiliation(s)
- Ismayil Tasdelen
- Department of Metabolic Diseases and The Netherlands Metabolomics Center, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Ruud Berger
- Department of Metabolic Diseases and The Netherlands Metabolomics Center, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Eric Kalkhoven
- Department of Metabolic Diseases and The Netherlands Metabolomics Center, University Medical Centre Utrecht, Utrecht, The Netherlands
- * E-mail:
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Deletion of the basement membrane heparan sulfate proteoglycan type XVIII collagen causes hypertriglyceridemia in mice and humans. PLoS One 2010; 5:e13919. [PMID: 21085708 PMCID: PMC2978080 DOI: 10.1371/journal.pone.0013919] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 10/15/2010] [Indexed: 01/15/2023] Open
Abstract
Background Lipoprotein lipase (Lpl) acts on triglyceride-rich lipoproteins in the peripheral circulation, liberating free fatty acids for energy metabolism or storage. This essential enzyme is synthesized in parenchymal cells of adipose tissue, heart, and skeletal muscle and migrates to the luminal side of the vascular endothelium where it acts upon circulating lipoproteins. Prior studies suggested that Lpl is immobilized by way of heparan sulfate proteoglycans on the endothelium, but genetically altering endothelial cell heparan sulfate had no effect on Lpl localization or lipolysis. The objective of this study was to determine if extracellular matrix proteoglycans affect Lpl distribution and triglyceride metabolism. Methods and Findings We examined mutant mice defective in collagen XVIII (Col18), a heparan sulfate proteoglycan present in vascular basement membranes. Loss of Col18 reduces plasma levels of Lpl enzyme and activity, which results in mild fasting hypertriglyceridemia and diet-induced hyperchylomicronemia. Humans with Knobloch Syndrome caused by a null mutation in the vascular form of Col18 also present lower than normal plasma Lpl mass and activity and exhibit fasting hypertriglyceridemia. Conclusions This is the first report demonstrating that Lpl presentation on the lumenal side of the endothelium depends on a basement membrane proteoglycan and demonstrates a previously unrecognized phenotype in patients lacking Col18.
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Bartosch B, Dubuisson J. Recent advances in hepatitis C virus cell entry. Viruses 2010; 2:692-709. [PMID: 21994653 PMCID: PMC3185649 DOI: 10.3390/v2030692] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 03/04/2010] [Accepted: 03/05/2010] [Indexed: 12/15/2022] Open
Abstract
More than 170 million patients worldwide are chronically infected with hepatitis C virus (HCV). Prevalence rates range from 0.5% in Northern European countries to 28% in some areas of Egypt. HCV is hepatotropic, and in many countries chronic hepatitis C is a leading cause of liver disease including fibrosis, cirrhosis and hepatocellular carcinoma. HCV persists in 50-85% of infected patients, and once chronic infection is established, spontaneous clearance is rare. HCV is a member of the Flaviviridae family, in which it forms its own genus. Many lines of evidence suggest that the HCV life cycle displays many differences to that of other Flaviviridae family members. Some of these differences may be due to the close interaction of HCV with its host's lipid and particular triglyceride metabolism in the liver, which may explain why the virus can be found in association with lipoproteins in serum of infected patients. This review focuses on the molecular events underlying the HCV cell entry process and the respective roles of cellular co-factors that have been implied in these events. These include, among others, the lipoprotein receptors low density lipoprotein receptor and scavenger receptor BI, the tight junction factors occludin and claudin-1 as well as the tetraspanin CD81. We discuss the roles of these cellular factors in HCV cell entry and how association of HCV with lipoproteins may modulate the cell entry process.
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Affiliation(s)
- Birke Bartosch
- INSERM, U871, 69003 Lyon, France
- Université Lyon 1, IFR62 Lyon-Est, 69008 Lyon, France
- Hospices Civils de Lyon, Hôtel Dieu, Service d’hépatologie et de gastroentérologie, 69002 Lyon, France
| | - Jean Dubuisson
- Université Lille Nord de France, F-59000 Lille, France; E-Mail: (J.D.)
- CNRS, Institut de Biologie de Lille (UMR8161), F-59021 Lille, France
- Institut Pasteur de Lille, F-59019 Lille, France
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7
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Abstract
The recent discovery of a dysfunctional mutation of GPIHBP1 in a man with chylomicronemia implicates this protein in human physiology. GPIHBP1 can be placed in the larger context of other molecular participants in chylomicron docking and hydrolysis on microvascular endothelium, caloric delivery, and remnant lipoprotein generation. Critical questions include the regulation—and dysregulation—of these processes in states of overnutrition, underexertion, obesity, insulin resistance, and diabetes.
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Affiliation(s)
- Kevin Jon Williams
- From the Section of Endocrinology, Diabetes, and Metabolism, Temple University School of Medicine, Philadelphia, Pa
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Weinstein MM, Yin L, Beigneux AP, Davies BSJ, Gin P, Estrada K, Melford K, Bishop JR, Esko JD, Dallinga-Thie GM, Fong LG, Bensadoun A, Young SG. Abnormal patterns of lipoprotein lipase release into the plasma in GPIHBP1-deficient mice. J Biol Chem 2008; 283:34511-8. [PMID: 18845532 DOI: 10.1074/jbc.m806067200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GPIHBP1-deficient mice (Gpihbp1(-/-)) exhibit severe chylomicronemia. GPIHBP1 is located within capillaries of muscle and adipose tissue, and expression of GPIHBP1 in Chinese hamster ovary cells confers upon those cells the ability to bind lipoprotein lipase (LPL). However, there has been absolutely no evidence that GPIHBP1 actually interacts with LPL in vivo. Heparin is known to release LPL from its in vivo binding sites, allowing it to enter the plasma. After an injection of heparin, we reasoned that LPL bound to GPIHBP1 in capillaries would be released very quickly, and we hypothesized that the kinetics of LPL entry into the plasma would differ in Gpihbp1(-/-) and control mice. Indeed, plasma LPL levels peaked very rapidly (within 1 min) after heparin in control mice. In contrast, plasma LPL levels in Gpihbp1(-/-) mice were much lower 1 min after heparin and increased slowly over 15 min. In keeping with that result, plasma triglycerides fell sharply within 10 min after heparin in wild-type mice, but were negligibly altered in the first 15 min after heparin in Gpihbp1(-/-) mice. Also, an injection of Intralipid released LPL into the plasma of wild-type mice but was ineffective in releasing LPL in Gpihbp1(-/-) mice. The observed differences in LPL release cannot be ascribed to different tissue stores of LPL, as LPL mass levels in tissues were similar in Gpihbp1(-/-) and control mice. The differences in LPL release after intravenous heparin and Intralipid strongly suggest that GPIHBP1 represents an important binding site for LPL in vivo.
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Affiliation(s)
- Michael M Weinstein
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
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9
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MacArthur JM, Bishop JR, Stanford KI, Wang L, Bensadoun A, Witztum JL, Esko JD. Liver heparan sulfate proteoglycans mediate clearance of triglyceride-rich lipoproteins independently of LDL receptor family members. J Clin Invest 2007; 117:153-64. [PMID: 17200715 PMCID: PMC1716206 DOI: 10.1172/jci29154] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Accepted: 10/03/2006] [Indexed: 12/17/2022] Open
Abstract
We examined the role of hepatic heparan sulfate in triglyceride-rich lipoprotein metabolism by inactivating the biosynthetic gene GlcNAc N-deacetylase/N-sulfotransferase 1 (Ndst1) in hepatocytes using the Cre-loxP system, which resulted in an approximately 50% reduction in sulfation of liver heparan sulfate. Mice were viable and healthy, but they accumulated triglyceride-rich lipoprotein particles containing apoB-100, apoB-48, apoE, and apoCI-IV. Compounding the mutation with LDL receptor deficiency caused enhanced accumulation of both cholesterol- and triglyceride-rich particles compared with mice lacking only LDL receptors, suggesting that heparan sulfate participates in the clearance of cholesterol-rich lipoproteins as well. Mutant mice synthesized VLDL normally but showed reduced plasma clearance of human VLDL and a corresponding reduction in hepatic VLDL uptake. Retinyl ester excursion studies revealed that clearance of intestinally derived lipoproteins also depended on hepatocyte heparan sulfate. These findings show that under normal physiological conditions, hepatic heparan sulfate proteoglycans play a crucial role in the clearance of both intestinally derived and hepatic lipoprotein particles.
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Affiliation(s)
- Jennifer M. MacArthur
- Biomedical Sciences Graduate Program and
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.
Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Joseph R. Bishop
- Biomedical Sciences Graduate Program and
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.
Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Kristin I. Stanford
- Biomedical Sciences Graduate Program and
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.
Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Lianchun Wang
- Biomedical Sciences Graduate Program and
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.
Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - André Bensadoun
- Biomedical Sciences Graduate Program and
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.
Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Joseph L. Witztum
- Biomedical Sciences Graduate Program and
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.
Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jeffrey D. Esko
- Biomedical Sciences Graduate Program and
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA.
Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.
Department of Medicine, University of California, San Diego, La Jolla, California, USA
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Kobayashi J, Nohara A, Kawashiri MA, Inazu A, Koizumi J, Nakajima K, Mabuchi H. Serum lipoprotein lipase mass: clinical significance of its measurement. Clin Chim Acta 2006; 378:7-12. [PMID: 17223095 DOI: 10.1016/j.cca.2006.12.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 11/24/2006] [Accepted: 12/05/2006] [Indexed: 11/24/2022]
Abstract
Lipoprotein lipase (LPL) is a lipolytic enzyme involved in catalyzing hydrolysis of triglycerides (TG) in chylomicrons and very low-density lipoprotein (VLDL) particles. Over the last decade, increasing attention has been paid to the clinical significance of measuring serum LPL protein mass without heparin injection to the study subjects. In earlier studies, this marker was utilized to classify LPL deficient subjects, which is an extremely rare metabolic disorder with a frequency of one in one million. Later, researchers paid more attention to the clinical significance of measuring this parameter in more common metabolic disorders. Studies have shown that pre-heparin plasma or serum LPL mass has significant relationships with serum lipids and lipoproteins, visceral fat area, insulin resistance, and even the development of coronary atherosclerosis in cross-sectional studies, although this might be a metabolic surrogate marker with almost no catalytic activities, which does not appear to be involved in catalyzing hydrolysis of TG in TG-rich lipoproteins. Recently, a prospective study has demonstrated that low serum LPL concentration predicts future coronary events. Taken together, we suggest that pre-heparin LPL mass in plasma or sera provide us with useful and important information on the development of metabolic disorders leading to atherosclerotic disease.
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Affiliation(s)
- Junji Kobayashi
- Department of Lipidology, Kanazawa University Graduate School of Medical Science Takara-machi 13-1, Kanazawa 920-8640, and Department of General Medicine, Kanazawa University Hospital, Japan.
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11
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Lindegaard MLS, Damm P, Mathiesen ER, Nielsen LB. Placental triglyceride accumulation in maternal type 1 diabetes is associated with increased lipase gene expression. J Lipid Res 2006; 47:2581-8. [PMID: 16940551 DOI: 10.1194/jlr.m600236-jlr200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Maternal diabetes can cause fetal macrosomia and increased risk of obesity, diabetes, and cardiovascular disease in adulthood of the offspring. Although increased transplacental lipid transport could be involved, the impact of maternal type 1 diabetes on molecular mechanisms for lipid transport in placenta is largely unknown. To examine whether maternal type 1 diabetes affects placental lipid metabolism, we measured lipids and mRNA expression of lipase-encoding genes in placentas from women with type 1 diabetes (n = 27) and a control group (n = 21). The placental triglyceride (TG) concentration and mRNA expression of endothelial lipase (EL) and hormone-sensitive lipase (HSL) were increased in placentas from women with diabetes. The differences were more pronounced in women with diabetes and suboptimal metabolic control than in women with diabetes and good metabolic control. Placental mRNA expression of lipoprotein lipase and lysosomal lipase were similar in women with diabetes and the control group. Immunohistochemistry showed EL protein in syncytiotrophoblasts facing the maternal blood and endothelial cells facing the fetal blood in placentas from both normal women and women with diabetes. These results suggest that maternal type 1 diabetes is associated with TG accumulation and increased EL and HSL gene expression in placenta and that optimal metabolic control reduces these effects.
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Affiliation(s)
- Marie L S Lindegaard
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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12
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Hishikawa K, Marumo T, Miura S, Nakanishi A, Matsuzaki Y, Shibata K, Kohike H, Komori T, Hayashi M, Nakaki T, Nakauchi H, Okano H, Fujita T. Leukemia inhibitory factor induces multi-lineage differentiation of adult stem-like cells in kidney via kidney-specific cadherin 16. Biochem Biophys Res Commun 2005; 328:288-91. [PMID: 15670782 DOI: 10.1016/j.bbrc.2004.12.167] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Indexed: 10/26/2022]
Abstract
Side population (SP) is reported to be a stem cell-rich population. In the presence of leukemia inhibitory factor (LIF), cultured kidney SP cells differentiated into multi-lineage in collagen gel but not in synthesized polymer that has no cell adhesion factor. In cultured kidney SP cells, gene expression of kidney-specific cadherin 16 was specifically upregulated in collagen gel but not in synthesized polymer. Moreover, decreasing cadherin 16 expression using siRNA abolished LIF-induced multi-lineage differentiation of kidney SP in collagen gel. These results indicated that LIF induced multi-lineage differentiation of adult stem-like cells in kidney via cadherin 16.
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Affiliation(s)
- Keiichi Hishikawa
- Department of Clinical Renal Regeneration, Graduate School of Medicine, University of Tokyo, Japan.
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13
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Chiba T, Nakazawa T, Yui K, Kaneko E, Shimokado K. VLDL induces adipocyte differentiation in ApoE-dependent manner. Arterioscler Thromb Vasc Biol 2003; 23:1423-9. [PMID: 12842848 DOI: 10.1161/01.atv.0000085040.58340.36] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To clarify the role of very low density lipoprotein (VLDL) and apolipoprotein E (apoE) in adipogenesis, we studied newly developed hyperlipidemic obese (ob/ob;apoE-/-) mice. Because hydrolysis of VLDL is believed to be the major source of adipogenic free fatty acids, a higher plasma level of VLDL in these mice should exaggerate obesity. METHODS AND RESULTS When fed a high-fat, high-cholesterol diet, ob/ob;apoE-/- mice did not show increased body weight or an increased amount of adipose tissue in spite of increased plasma VLDL levels, whereas ob/ob mice showed an increased body weight and amount of adipose tissue, suggesting that there is a novel apoE-dependent pathway for adipogenesis. In vitro experiments using bone marrow stromal cells and 3T3-L1 cells confirmed this notion. ApoE-deficient VLDL did not induce adipogenesis, whereas normal VLDL induced adipogenesis in these cells. The incubation of apoE-deficient VLDL with recombinant human apoE restored its adipogenic activity. Tetrahydrolipstatin, a lipoprotein lipase inhibitor, did not affect the adipogenic activity of VLDL, suggesting that hydrolysis of VLDL did not play a major role in its effects. In fact, lipid components of VLDL or free fatty acids induced only partial adipogenesis. CONCLUSIONS Our findings indicate that VLDL induces adipogenesis in an apoE-dependent manner both in vitro and in vivo.
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Affiliation(s)
- Tsuyoshi Chiba
- Tokyo Medical and Dental University Graduate School, Vascular Medicine and Geriatrics, Tokyo, Japan
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14
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Nasstrom B, Stegmayr BG, Olivecrona G, Olivecrona T. Lower plasma levels of lipoprotein lipase after infusion of low molecular weight heparin than after administration of conventional heparin indicate more rapid catabolism of the enzyme. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 2003; 142:90-9. [PMID: 12960955 DOI: 10.1016/s0022-2143(03)00059-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The functional pool of lipoprotein lipase (LPL) is anchored to heparan sulfate at the vascular endothelium. Injection of heparin releases the enzyme into the circulating blood. Animal experiments have shown that the enzyme is then extracted and degraded by the liver. Low molecular weight (LMW) heparin preparations are widely used in the clinic and are supposed to release less LPL. In this study, we infused a LMW heparin into healthy volunteers for 8 hours. The peak of LPL activity was only about 30% and the subsequent plateau of LPL activity only about 40% compared with those seen with conventional heparin. When a bolus of heparin was given after 4 hours' infusion of LMW or conventional heparin, only relatively small, and similar, amounts of LPL entered plasma. This suggests that the difference between LMW and conventional heparin lay in the ability to retain LPL in the circulating blood, not in the ability to release the lipase. Triglycerides (TGs) decreased when the heparin infusion was started, as expected from the high circulating LPL activities. After 1 to 2 hours, TG levels increased again, and after 8 hours they were about twice as high as before the heparin infusion. This indicates that the amount of LPL available for lipoprotein metabolism had become critically low in relation to TG transport rates. This study indicates that LMW heparin compared with conventional heparin causes as much or more depletion of LPL and subsequent impairment of TG clearing.
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Affiliation(s)
- Birgit Nasstrom
- Division of Nephrology, Department of Internal Medicine, Umeå University, Umeå, Sweden
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15
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Sekiya N, Kogure T, Kita T, Kasahara Y, Sakakibara I, Goto H, Shibahara N, Shimada Y, Terasawa K. Reduction of plasma triglyceride level and enhancement of plasma albumin concentration by Oren-gedoku-to administration. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2002; 9:455-460. [PMID: 12222668 DOI: 10.1078/09447110260571724] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Oren-gedoku-to (Huanglian-Jie-Du-Tang, OGT) has been used for the treatment of cerebrovascular disease, hypertension, gastritis and liver disease in Japan. The present study was to test whether ingestion of OGT extract (TJ-15) would affect the metabolism of fatty acids and the usual antioxidant molecule (such as albumin, uric acid and bilirubin) levels in human plasma. After the administration of TJ-15, plasma total cholesterol and the triglyceride level significantly decreased, and lipoprotein lipase mass increased. Significant enhancement of plasma albumin level and reduction of the total plasma protein level resulted in an increment of the albumin/globulin ratio. Plasma fibrinogen, an independent risk factor for cerebrovascular disease, declined considerably, but the reduction was not statistically significant. The findings of this study suggest that ingestion of TJ-15 improves the microcirculation through lipid and protein metabolisms, and is useful for the treatment of cerebral vascular attack in human.
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Affiliation(s)
- N Sekiya
- Department of Japanese Oriental Medicine, Faculty of Medicine, Toyama Medical and Pharmaceutical University.
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16
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Ginsberg HN, Goldberg IJ. The Pancreas and Lipoprotein Metabolism. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Park K, Verchere CB. Identification of a heparin binding domain in the N-terminal cleavage site of pro-islet amyloid polypeptide. Implications for islet amyloid formation. J Biol Chem 2001; 276:16611-6. [PMID: 11145957 DOI: 10.1074/jbc.m008423200] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Islet amyloid deposits are a characteristic pathologic lesion of the pancreas in type 2 diabetes and are composed primarily of the islet beta cell peptide islet amyloid polypeptide (IAPP or amylin) as well as the basement membrane heparan sulfate proteoglycan perlecan. Impaired processing of the IAPP precursor has been implicated in the mechanism of islet amyloid formation. The N- and C-terminal cleavage sites where pro-IAPP is processed by prohormone convertases contain a series of basic amino acid residues that we hypothesized may interact with heparan sulfate proteoglycans. This possibility was tested using affinity chromatography by applying synthetic fragments of pro-IAPP to heparin-agarose and heparan sulfate-Sepharose. An N-terminal human pro-IAPP fragment (residues 1-30) was retained by both heparin-agarose and heparan sulfate-Sepharose, eluting at 0.18 m NaCl at pH 7.5. Substitution of alanine residues for two basic residues in the N-terminal cleavage site abolished heparin and heparan sulfate binding activity. At pH 5.5, the affinity of the wild-type peptide for heparin/heparan sulfate was increased, implying a role for histidine residues at positions 6 and 28 of pro-IAPP. A C-terminal pro-IAPP fragment (residues 41-67) had no specific affinity for either heparin or heparan sulfate, and the N- or C-terminal fragments had only weak affinity for chondroitin sulfate. These data suggest that monomeric N-terminal human pro-IAPP contains a heparin binding domain that is lost during normal processing of pro-IAPP.
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Affiliation(s)
- K Park
- Department of Pathology and Laboratory Medicine and the British Columbia Research Institute for Children's and Women's Health, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
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18
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Lutz EP, Merkel M, Kako Y, Melford K, Radner H, Breslow JL, Bensadoun A, Goldberg IJ. Heparin-binding defective lipoprotein lipase is unstable and causes abnormalities in lipid delivery to tissues. J Clin Invest 2001; 107:1183-92. [PMID: 11342582 PMCID: PMC209279 DOI: 10.1172/jci11774] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Lipoprotein lipase (LpL) binding to heparan sulfate proteoglycans (HSPGs) is hypothesized to stabilize the enzyme, localize LpL in specific capillary beds, and route lipoprotein lipids to the underlying tissues. To test these hypotheses in vivo, we created mice expressing a human LpL minigene (hLpL(HBM)) carrying a mutated heparin-binding site. Three basic amino acids in the carboxyl terminal region of LpL were mutated, yielding an active enzyme with reduced heparin binding. Mice expressing hLpL(HBM) accumulated inactive human LpL (hLpL) protein in preheparin blood. hLpL(HBM) rapidly lost activity during a 37 degrees C incubation, confirming a requirement for heparin binding to stabilize LPL: Nevertheless, expression of hLpL(HBM) prevented the neonatal demise of LpL knockout mice. On the LpL-deficient background hLpL(HBM) expression led to defective targeting of lipids to tissues. Compared with mice expressing native hLpL in the muscle, hLpL(HBM) transgenic mice had increased postprandial FFAs, decreased lipid uptake in muscle tissue, and increased lipid uptake in kidneys. Thus, heparin association is required for LpL stability and normal physiologic functions. These experiments confirm in vivo that association with HSPGs can provide a means to maintain proteins in their stable conformations and to anchor them at sites where their activity is required.
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Affiliation(s)
- E P Lutz
- Department of Medicine, Columbia University, New York, New York 10032, USA
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19
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Park K, Verchere CB. Identification of a Heparin Binding Domain in the N-terminal Cleavage Site of Pro-islet Amyloid Polypeptide. J Biol Chem 2001. [DOI: 10.1074/jbc.m008423200%20m008423200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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20
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Obunike JC, Lutz EP, Li Z, Paka L, Katopodis T, Strickland DK, Kozarsky KF, Pillarisetti S, Goldberg IJ. Transcytosis of lipoprotein lipase across cultured endothelial cells requires both heparan sulfate proteoglycans and the very low density lipoprotein receptor. J Biol Chem 2001; 276:8934-41. [PMID: 11121409 DOI: 10.1074/jbc.m008813200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipoprotein lipase (LPL), the major enzyme responsible for the hydrolysis of circulating lipoprotein triglyceride molecules, is synthesized in myocytes and adipocytes but functions while bound to heparan sulfate proteoglycans (HSPGs) on the luminal surface of vascular endothelial cells. This requires transfer of LPL from the abluminal side to the luminal side of endothelial cells. Studies were performed to investigate the mechanisms of LPL transcytosis using cultured monolayers of bovine aortic endothelial cells. We tested whether HSPGs and members of the low density lipoprotein (LDL) receptor superfamily were involved in transfer of LPL from the basolateral to the apical side of cultured endothelial cells. Heparinase/heparinitase treatment of the basolateral cell surface or addition of heparin to the basolateral medium decreased the movement of LPL. This suggested a requirement for HSPGs. To assess the role of receptors, we used either receptor-associated protein, the 39-kDa inhibitor of ligand binding to the LDL receptor-related protein and the very low density lipoprotein (VLDL) receptor, or specific receptor antibodies. Receptor-associated protein reduced (125)I-LPL and LPL activity transfer across the monolayers. When the basolateral surface of the cells was treated with antibodies, only anti-VLDL receptor antibodies inhibited transcytosis. Moreover, overexpression of the VLDL receptor using adenoviral-mediated gene transfer increased LPL transcytosis. Thus, movement of active LPL across endothelial cells involves both HSPGs and VLDL receptor.
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Affiliation(s)
- J C Obunike
- Department of Medicine, Division of Preventive Medicine and Nutrition, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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21
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Totsuka M, Miyashita Y, Ito Y, Watanabe H, Murano T, Shirai K. Enhancement of preheparin serum lipoprotein lipase mass by bezafibrate administration. Atherosclerosis 2000; 153:175-9. [PMID: 11058713 DOI: 10.1016/s0021-9150(00)00394-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
To clarify the clinical implication of preheparin serum lipoprotein lipase mass (preheparin LpL mass), we studied the relationships between preheparin LpL mass and serum lipids, including midband lipoproteins, which migrate between very low density lipoproteins and low density lipoproteins on polyacrylamide gel disc electrophoresis, in hyperlipidemias. And we also studied the changes of preheparin LpL mass in hypertriglyceridemic patients during bezafibrate administration, which is known to enhance LpL activity in postheparin plasma. Preheparin LpL mass correlated positively with high-density lipoprotein-cholesterol (HDL-C) (r=0.418, P<0.01) and negatively with triglyceride (TG) (r=-0.256, P<0.01), but did not correlate with total cholesterol (TC) in 64 hyperlipidemic (type IIa, IIb and IV) patients. The midband lipoproteins were observed in 80% of hypertriglyceridemic patients (32/40). Preheparin LpL mass in midband lipoprotein-positive subjects was lower significantly than that in midband-negative subjects. When bezafibrate (400 mg/day) was administrated to 40 hypertriglyceridemic patients for 4 months, TG level significantly decreased (-49+/-7%, P<0.01), TC levels decreased (-11+/-4%, not significant), and HDL-C levels increased (+27+/-4%, P<0.01). The midband lipoproteins disappeared in 95% of patients. Preheparin LpL mass significantly increased (+25+/-6%, P<0. 0005). In nine patients who stopped bezafibrate, TG levels significantly increased (+49+/-7%, P<0.01) and HDL-C levels decreased (-27+/-4%, P<0.01). Preheparin LPL mass significantly decreased (-25+/-6%, P<0.0005). These results suggested that bezafibrate administration enhanced preheparin LpL mass. And it might be implicated that enhanced LpL production by bezafibrate could reflect an increase of preheparin LpL mass.
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Affiliation(s)
- M Totsuka
- Department of Internal Medicine, Sakura Hospital, School of Medicine, Toho University, 564-1, Shimoshizu, Sakura-shi, 285-8741, Chiba, Japan
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22
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Babaev VR, Patel MB, Semenkovich CF, Fazio S, Linton MF. Macrophage lipoprotein lipase promotes foam cell formation and atherosclerosis in low density lipoprotein receptor-deficient mice. J Biol Chem 2000; 275:26293-9. [PMID: 10858435 DOI: 10.1074/jbc.m002423200] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The role of macrophage lipoprotein lipase (LPL) expression in atherosclerotic lesion formation was examined in low density lipoprotein receptor (LDLR(-/-)) mice using dietary conditions designed to induce either fatty streak lesions or complex atherosclerotic lesions. First, LDLR(-/-) mice chimeric for macrophage LPL expression were created by transplantation of lethally irradiated female LDLR(-/-) mice with LPL(-/-) (n = 12) or LPL(+/+) (n = 14) fetal liver cells as a source of hematopoietic cells. To induce fatty streak lesions, these mice were fed a Western diet for 8 weeks, resulting in severe hypercholesterolemia. There were no differences in plasma post-heparin LPL activity, serum lipid levels, or lipoprotein distribution between these two groups. The mean lesion area in the proximal aorta in LPL(-/-) --> LDLR(-/-) mice was significantly reduced by 33% compared with LPL(+/+) --> LDLR(-/-) mice, and a similar reduction (38%) in lesion area was found by en face analysis of the aortae. To induce complex atherosclerotic lesions, female LDLR(-/-) mice were lethally irradiated, transplanted with LPL(-/-) (n = 14), LPL(+/-) (n = 13), or LPL(+/+) (n = 14) fetal liver cells, and fed the Western diet for 19 weeks. Serum cholesterol and triglyceride levels did not differ between the three groups. After 19 weeks of diet, the lesions in the proximal aorta were complex with relatively few macrophages expressing LPL protein and mRNA in LPL(+/+) --> LDLR(-/-) mice. Analysis of cross-sections of the proximal aorta demonstrated no differences in the extent of lesion area between the groups, whereas en face analysis of the aortae revealed a dose-dependent effect of macrophage LPL on mean aortic lesion area in LPL(-/-) --> LDLR(-/-), LPL(-/+) --> LDLR(-/-), and LPL(+/+) --> LDLR(-/-) mice (1.8 +/- 0. 2%, 3.5 +/- 0.5% and 5.9 +/- 0.8%, respectively). Taken together, these data indicate that macrophage LPL expression in the artery wall promotes atherogenesis during foam cell lesion formation, but this impact may be limited to macrophage-rich lesions.
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Affiliation(s)
- V R Babaev
- Departments of Medicine, Pathology, and Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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23
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Babaev VR, Fazio S, Gleaves LA, Carter KJ, Semenkovich CF, Linton MF. Macrophage lipoprotein lipase promotes foam cell formation and atherosclerosis in vivo. J Clin Invest 1999; 103:1697-705. [PMID: 10377176 PMCID: PMC408384 DOI: 10.1172/jci6117] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Expression of lipoprotein lipase (LPL) by the macrophage has been proposed to promote foam cell formation and atherosclerosis, primarily on the basis of in vitro studies. LPL-deficient mice might provide a model for testing the role of LPL secretion by the macrophage in an in vivo system. Unfortunately, homozygous deficiency of LPL in the mouse is lethal shortly after birth. Because the fetal liver is the major site of hematopoiesis in the developing fetus, transplantation of C57BL/6 mice with LPL-/- fetal liver cells (FLCs) was used to investigate the physiologic role of macrophage LPL expression in vivo. Thirty-four female C57BL/6 mice were lethally irradiated and reconstituted with FLCs from day 14 LPL+/+, LPL+/-, and LPL-/- donors. No significant differences were detected in plasma levels of post-heparin LPL activity or in serum cholesterol or triglyceride levels between the 3 groups on either a chow diet or an atherogenic diet. After 19 weeks on the atherogenic diet, aortae were collected for quantitative analysis of the extent of aortic atherosclerosis. LPL expression was detected by immunocytochemistry and in situ hybridization in macrophages of aortic atherosclerotic lesions of LPL+/+-->C57BL/6 and LPL+/--->C57BL/6 mice, but not in LPL-/--->C57BL/6 mice, whereas myocardial cells expressed LPL in all groups. The mean aortic lesion area was reduced by 55% in LPL-/--->C57BL/6 mice compared with LPL+/+-->C57BL/6 mice and by 45% compared with LPL+/--->C57BL/6 mice, respectively. These data demonstrate in vivo that LPL expression by macrophages in the artery wall promotes foam cell formation and atherosclerosis. off
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Affiliation(s)
- V R Babaev
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37323, USA
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24
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Antohe F, Poznansky MJ, Simionescu M. Low density lipoprotein binding induces asymmetric redistribution of the low density lipoprotein receptors in endothelial cells. Eur J Cell Biol 1999; 78:407-15. [PMID: 10430022 DOI: 10.1016/s0171-9335(99)80083-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The uptake and transport of cholesterol-carrying low density lipoprotein (LDL) by the arterial wall is a continuous dynamic process, contributing to the cholesterol homeostasis in the plasma and in the cellular components of the vessel wall. Upon exposure to endothelial cells (EC), LDL interacts in part, with specific surface receptors (LDL-R). In this study we questioned: (i) the distribution of LDL receptors on the apical and basal cell membranes in endothelial cells; (ii) the role of LDL receptors in the control of cholesterol homeostasis and (iii) the translocation of LDL receptor across the EC. To this purpose bovine aortic EC were cultured on filters in a double-chamber system, in Dulbecco's medium supplemented either with 10% fetal calf serum (FCS) or with 10% lipoprotein-deficient serum (LPDS). The cells were exposed for 3h to 13H]acetate (40 microCi) added to both compartments of the cell culture inserts. The newly synthesized [3H]cholesterol was detected by thin layer chromatography and quantified by liquid scintillation counting. The LDL-R were detected in EC protein homogenates by immunoblotting using a monoclonal antibody against LDL-R (IgG-C7); the intracellular pathway of LDL-R was examined by electron microscopy using a complex made of protein A 5 nm or 20 nm colloidal gold particles and an anti-LDL receptor antibody (Au-PA-C7). To evaluate the distribution and the transport of LDL-R from one cell surface to the other, EC grown in LPDS were radioiodinated either on the apical or on the basolateral surface, incubated on the same surface with LDL, and subsequently biotinylated on the opposite non-radiolabeled surface. The EC were further solubilized and the protein extract immunoprecipitated with anti-LDL-R antibody or with mouse IgG (as control). The eluted antigen-antibody complexes were precipitated with streptavidin-agarose beads, solubilized, and subjected to SDS-PAGE. The results showed that: (a) the LDL-R were present on both endothelial cell fronts; (b) using the complex Au-PA-C7, the LDL-R were localized in endothelial plasmalemmal vesicles as well as coated pits and coated vesicles in multivesicular bodies and lysosomes, irrespective of the cell surface exposed to the complex; (c) biochemical assays indicated that upon ligand binding, the LDL-R were translocated preferentially from the apical to the basal plasma membrane.
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Affiliation(s)
- F Antohe
- Institute of Cellular Biology and Pathology Nicolae Simionescu, Bucharest, Romania
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25
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Mamputu JC, Renier G. Differentiation of human monocytes to monocyte-derived macrophages is associated with increased lipoprotein lipase-induced tumor necrosis factor-alpha expression and production: a process involving cell surface proteoglycans and protein kinase C. Arterioscler Thromb Vasc Biol 1999; 19:1405-11. [PMID: 10364070 DOI: 10.1161/01.atv.19.6.1405] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The aim of the present study was to (1) evaluate the responsiveness of human mononuclear cells to lipoprotein lipase (LPL), as assessed by tumor necrosis factor-alpha (TNFalpha) production, during the process of differentiation of monocytes to macrophages, and (2) determine the mechanisms by which LPL exerts its effect on these cells. Treatment of human monocytes with purified endotoxin-free bovine LPL (1 microgram/mL) resulted in a 161+/-15% increase in TNFalpha production over control values (P<0.01). A further increase in TNFalpha production was observed after treatment of monocyte-derived macrophages (MDMs) with LPL (490+/-81% over control values, P<0.01). Increased TNFalpha mRNA expression and protein kinase C activity were also observed in LPL-treated human monocytes and MDMs. These LPL effects were abrogated by the specific protein kinase C inhibitor calphostin C (1 micromol/L). Although heparinase totally abolished LPL-induced TNFalpha production in human monocytes, this agent did not significantly inhibit LPL effect in human MDMs. In contrast, treatment of MDMs with chondroitinase suppressed LPL-induced TNFalpha production. Taken together, these data suggest that (1) differentiation of human monocytes to MDMs is associated with increased LPL-induced TNFalpha mRNA expression and production, (2) a protein kinase C-dependent pathway is involved in the induction of TNFalpha by LPL in these cells, and (3) LPL effect is mediated by cell surface proteoglycans. As MDMs secrete LPL in the vascular wall, we propose that LPL, by acting as an autocrine activator of MDM function, may contribute to the high level of TNFalpha found in the atheromatous lesion.
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Affiliation(s)
- J C Mamputu
- CHUM Research Center, Notre-Dame Campus, Department of Nutrition, University of Montreal, Montreal, Quebec, Canada
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26
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Mamputu JC, Desfaits AC, Renier G. Lipoprotein lipase enhances human monocyte adhesion to aortic endothelial cells. J Lipid Res 1997. [DOI: 10.1016/s0022-2275(20)37147-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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27
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Petitou M, Duchaussoy P, Bernat A, Hoffmann P, Herbert J. A synthetic heparin/heparan sulfate-like decasaccharide releases lipase activity in vivo. Chemical synthesis and biological activity. Bioorg Med Chem Lett 1997. [DOI: 10.1016/s0960-894x(97)00361-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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28
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Lucas M, Iverius PH, Strickland DK, Mazzone T. Lipoprotein lipase reduces secretion of apolipoprotein E from macrophages. J Biol Chem 1997; 272:13000-5. [PMID: 9148908 DOI: 10.1074/jbc.272.20.13000] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Macrophages are a significant source of lipoprotein lipase (LPL) and apolipoprotein E (apo E) in the developing arterial wall lesion, and each of these proteins can importantly modulate lipid and lipoprotein metabolism by arterial wall cells. LPL and apo E share a number of cell surface binding sites, including proteoglycans, and we have previously shown that proteoglycans are important for modulating net secretion of apoprotein E from macrophages. We therefore evaluated a potential role for LPL in modulating net secretion of macrophage-derived apo E. In pulse-chase experiments, addition of LPL during the chase period produced a decrease in secretion of apoprotein E from human monocyte-derived macrophages, from the human monocytic THP1 cell line, and from J774 cells transfected to constitutively express a human apo E cDNA. LPL similarly reduced apo E secretion when it was prebound to the macrophage cell surface at 4 degrees C. A native LPL particle was required to modulate apo E secretion; addition of monomers and aggregates did not produce the same effect. Depletion of cell surface proteoglycans by a 72-h incubation in 4-methylumbelliferyl-beta-D-xyloside did not attenuate the ability of LPL to reduce apo E secretion. However, addition of receptor-associated protein attenuated the effect of LPL on apo E secretion. Although LPL could mediate removal of exogenously added apo E from the culture medium, detailed pulse-chase analysis suggested that it primarily prevented release of newly synthesized apo E from the cell layer. Cholesterol loading of cells or antibodies to the low density lipoprotein receptor attenuated LPL effects on apo E secretion. We postulate that LPL sequesters endogenously synthesized apo E at the cell surface by a low density lipoprotein receptor-dependent mechanism. Such post-translational regulation of macrophage apo E secretion by LPL could significantly influence apo E accumulation in arterial vessel wall lesions.
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Affiliation(s)
- M Lucas
- Department of Medicine, Rush Medical College, Chicago, Illinois 60612, USA
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29
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Park JW, Lee SY, Yang JY, Rho HW, Park BH, Lim SN, Kim JS, Kim HR. Effect of carbonyl cyanide m-chlorophenylhydrazone (CCCP) on the dimerization of lipoprotein lipase. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1344:132-8. [PMID: 9030190 DOI: 10.1016/s0005-2760(96)00146-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lipoprotein lipase (LPL), an enzyme playing the central role in triglyceride metabolism, is a glycoprotein and a homodimer of identical subunits. Dimerization and proper processing of oligosaccharide chains are important maturation steps in post-translational regulation of enzyme activity. Indirect evidences suggest that dimerization of LPL occurs in endoplasmic reticulum (ER) or Golgi. In this study, we investigated the dimerization status of LPL in 3T3-L1 adipocytes, using sucrose density gradient ultracentrifugation and carbonyl cyanide m-chlorophenylhydrazone (CCCP), an inhibitor of ER-Golgi protein transport. In the presence of CCCP, no increase of cellular LPL activity was detected during 2 b of recovery period after the depletion of LPL, with heparin and cycloheximide. Only endoglycosidase H (endo H)-sensitive subunits were found in CCCP-treated cells after endo H digestion, suggesting that inactive LPL was retained in ER. In the presence of castanospermine, an inhibitor of ER glucosidase I, LPL subunits of both control and CCCP-treated cells had same molecular weight, indicating that complete oligosaccharides were transferred to LPL subunits in the presence of CCCP. In sucrose density gradient ultracentrifugation, all the LPL protein synthesized in the presence of CCCP was found at the dimeric fractions as in control cells. Most of LPL protein in control cells showed high affinity for heparin, and there was no difference between the control and CCCP-treated cells. These results suggest that dimerization and acquisition of high affinity for heparin of LPL can occur in ER of CCCP-treated cells without acquisition of catalytic activity.
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Affiliation(s)
- J W Park
- Department of Biochemistry, Chonbuk National University, Medical School, Chonju, South Korea.
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30
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Okamoto M, Mori S, Ishimaru M, Tohge H, Nakata Y, Endo H. An enzyme- linked immunosorbent assay for heparan sulfate proteoglycans. Life Sci 1997; 60:1811-9. [PMID: 9150421 DOI: 10.1016/s0024-3205(97)00141-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An enzyme- linked immunosorbent assay (ELISA) for heparan sulfate proteoglycan (HSPG) was developed based on the high affinity binding profile of HSPG to lipoprotein lipase (LPL). LPL was shown to bind to precoated HSPG in dose dependent manner and was determined spectrophotometrically using specific anti- LPL antibody. This ELISA allowed to evaluate HSPG produced by PC12 cell with clear linearity at range of 10 - 500 ng/ml. Soluble chondroitin sulfate proteoglycan (CSPG) from rat brain, which was not detectable by this method, did not exhibit any inhibitory effects on affinity binding of HSPG to LPL, even if 8 times higher concentrations of CSPG to HSPG was added. The sensitivity of this ELISA was about 100 times higher than that of conventional carbazole reaction method. These findings indicated its potential usefulness of this method for measuring small amounts of HSPG capable of binding to LPL and for studying biological implications of HSPG - LPL interaction.
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Affiliation(s)
- M Okamoto
- School of Health Sciences, Okayama University, Shikata-cho, Japan
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31
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Pang L, Sivaram P, Goldberg IJ. Cell-surface expression of an amino-terminal fragment of apolipoprotein B increases lipoprotein lipase binding to cells. J Biol Chem 1996; 271:19518-23. [PMID: 8702644 DOI: 10.1074/jbc.271.32.19518] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Previous studies (Sivaram, P., Choi, S. Y., Curtiss, L. K., and Goldberg, I. J.(1994) J. Biol. Chem. 269, 9409-9412) from this laboratory showed that the NH2-terminal region of apoB (NTAB) has binding domains for lipoprotein lipase (LPL). LPL binding to endothelial cells, we hypothesize, involves interaction both with heparan sulfate proteoglycans and with a protein that has homology to NTAB. To test whether cell-surface NTAB would increase the amount and affinity of LPL binding to cells, we produced stable Chinese hamster ovary cell lines that have NTAB anchored to the cell surface. A cDNA encoding the amino-terminal 17% of apoB (apoB17) was fused to a cDNA coding for the last 37 amino acids of decay-accelerating factor (DAF), which contains the signal for glycosylphosphatidylinositol anchor attachment. The fused construct was sequence-verified and cloned into expression vector pCMV5. The pCMV5-apoB17-DAF plasmid was cotransfected with a neomycin resistance gene into wild-type (WT) cells and mutant heparan sulfate proteoglycan-deficient Chinese hamster ovary cells (745 cells), and stable cell lines were established. Expression of apoB17 on the cell surface was confirmed by the release of apoB17 by phosphatidylinositol-specific phospholipase C. LPL binding to WT and apoB17-DAF-transfected cells was determined. Using 0.8-6 microg of LPL, 1.3-2.2-fold more LPL associated with apoB17-DAF WT cells compared with WT cells; apoB17-DAF also increased LPL binding to 745 cells. After heparinase treatment, LPL binding to apoB17-DAF cells was still greater than to treated WT cells. This increased binding to apoB17-DAF cells was almost abolished by treatment of cells with phosphatidylinositol-specific phospholipase C or anti-apoB monoclonal antibody. LPL dissociated from WT cells with k-1 = 2.55 x 10(-2) min-1, whereas LPL dissociated more slowly from apoB17-DAF-containing cells with k-1 = 1.08 x 10(-2) min-1. Furthermore, almost 95% of the LPL on WT cells was dissociated by 1 M NaCl, while only 65% of the LPL dissociated from apoB17-DAF cells at the same high salt concentration. Similarly, in high salt, more LPL remained associated with apoB17-DAF cells than with nontransfected 745 cells. These data show that NTAB on cell surfaces can function as a LPL-binding protein. Moreover, they demonstrate that LPL association with cells can be increased by simultaneously binding to both proteoglycan and non-proteoglycan binding sites.
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Affiliation(s)
- L Pang
- Division of Preventive Medicine and Nutrition, Department of Medicine, Columbia University, New York, New York 10032, USA
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32
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Medh JD, Bowen SL, Fry GL, Ruben S, Andracki M, Inoue I, Lalouel JM, Strickland DK, Chappell DA. Lipoprotein lipase binds to low density lipoprotein receptors and induces receptor-mediated catabolism of very low density lipoproteins in vitro. J Biol Chem 1996; 271:17073-80. [PMID: 8663292 DOI: 10.1074/jbc.271.29.17073] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Lipoprotein lipase (LPL), the major enzyme responsible for the hydrolysis of plasma triglycerides, promotes binding and catabolism of triglyceride-rich lipoproteins by various cultured cells. Recent studies demonstrate that LPL binds to three members of the low density lipoprotein (LDL) receptor family, including the LDL receptor-related protein (LRP), GP330/LRP-2, and very low density lipoprotein (VLDL) receptors and induces receptor-mediated lipoprotein catabolism. We show here that LDL receptors also bind LPL and mediate LPL-dependent catabolism of large VLDL with Sf 100-400. Up-regulation of LDL receptors by lovastatin treatment of normal human foreskin fibroblasts (FSF cells) resulted in an increase in LPL-induced VLDL binding and catabolism to a level that was 10-15-fold greater than in LDL receptor-negative fibroblasts, despite similar LRP activity in both cell lines. This indicates that the contribution of LRP to LPL-dependent degradation of VLDL is small when LDL receptors are maximally up-regulated. Furthermore studies in LRP-deficient murine embryonic fibroblasts showed that the level of LPL-dependent degradation of VLDL was similar to that in normal murine embryonic fibroblasts. LPL also promoted the internalization of protein-free triglyceride emulsions; lovastatin-treatment resulted in 2-fold higher uptake in FSF cells, indicating that LPL itself could bind to LDL receptors. However, the lower induction of emulsion catabolism as compared with native VLDL suggests that LPL-induced catabolism via LDL receptors is only partially dependent on receptor binding by LPL and instead is primarily due to activation of apolipoproteins such as apoE. A fusion protein between glutathione S-transferase and the catalytically inactive carboxyl-terminal domain of LPL (GST-LPLC) also induced binding and catabolism of VLDL. However GST-LPLC was not as active as native LPL, indicating that lipolysis is required for a maximal LPL effect. Mutations of critical tryptophan residues in GST-LPLC that abolished binding to VLDL converted the protein to an inhibitor of lipoprotein binding to LDL receptors. In solid-phase assays using immobilized receptors, LDL receptors bound to LPL in a dose-dependent manner. Both LPL and GST-LPLC promoted binding of VLDL to LDL receptor-coated wells. These results indicate that LPL binds to LDL receptors and suggest that the carboxyl-terminal domain of LPL contributes to this interaction.
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Affiliation(s)
- J D Medh
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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Rensen PC, van Berkel TJ. Apolipoprotein E effectively inhibits lipoprotein lipase-mediated lipolysis of chylomicron-like triglyceride-rich lipid emulsions in vitro and in vivo. J Biol Chem 1996; 271:14791-9. [PMID: 8662966 DOI: 10.1074/jbc.271.25.14791] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Apolipoprotein E (apoE) is an important determinant for the liver uptake of triglyceride-rich lipoproteins and emulsions by the remnant receptor. In the current study, we assessed an additional role of apoE as modulator of the metabolism of triglyceride-rich lipoproteins in vitro and in vivo. Glycerol tri[3H]oleate [14C]cholesteryl oleate double-labeled triglyceride-rich emulsions were injected into fasted rats. The serum half-life of glycerol tri[3H]oleate was 3-fold faster (5.4 min) than that of [14C]cholesteryl oleate (16.7 min), confirming lipoprotein lipase (LPL)-mediated processing. To establish a specific effect of apoE on emulsion lipolysis rather than liver uptake, rats were functionally hepatectomized, and hypo(apo)lipoproteinemia was induced by 17alpha-ethinyl estradiol treatment. An apoE concentration-dependent inhibition of emulsion-triglyceride hydrolysis was observed, reaching a 14.8-fold increased half-life of glycerol tri[3H]oleate as compared with that in the absence of exogenous apoE. The mechanism and specificity of the effect of apoE on emulsion lipolysis by purified LPL was assessed in vitro. Addition of apoE to glycerol tri[3H]oleate-labeled emulsions led to a concentration-dependent inhibition of [3H]oleate release (9.5% residual LPL activity at 60 microg/ml apoE), while apoA-I was ineffective. The inhibitory effect of apoE was not abolished by reductive methylation of lysine residues, whereas selective modification of arginine residues by 1,2-cyclohexadione completely cancelled the inhibitory effect of apoE. It is concluded that apoE can specifically inhibit the LPL-mediated hydrolysis of emulsion triglycerides both in vitro and in vivo, and that arginine residues in apoE are essential for this effect. We suggest that in addition to its role in receptor recognition, apoE also modulates the LPL-mediated processing of triglyceride-rich lipoproteins.
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Affiliation(s)
- P C Rensen
- Division of Biopharmaceutics, Leiden-Amsterdam Center for Drug Research, University of Leiden, Sylvius Laboratories, 2300 RA Leiden, The Netherlands
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34
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Goldberg IJ. Lipoprotein lipase and lipolysis: central roles in lipoprotein metabolism and atherogenesis. J Lipid Res 1996. [DOI: 10.1016/s0022-2275(20)37569-6] [Citation(s) in RCA: 323] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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35
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David G, Danneels A, Duerr J, Grootjans J, Mertens G, Nackaerts K, Romaris M, Schrurs B, Steinfeld R, Vekemans S. Heparan sulfate proteoglycans. Essential co-factors in receptor-mediated processes with relevance to the biology of the vascular wall. Atherosclerosis 1995. [DOI: 10.1016/0021-9150(95)90074-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Kofoed-Enevoldsen A. Heparan sulphate in the pathogenesis of diabetic nephropathy. DIABETES/METABOLISM REVIEWS 1995; 11:137-60. [PMID: 7555565 DOI: 10.1002/dmr.5610110205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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37
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Choi SY, Sivaram P, Walker DE, Curtiss LK, Gretch DG, Sturley SL, Attie AD, Deckelbaum RJ, Goldberg IJ. Lipoprotein lipase association with lipoproteins involves protein-protein interaction with apolipoprotein B. J Biol Chem 1995; 270:8081-6. [PMID: 7713910 DOI: 10.1074/jbc.270.14.8081] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Lipoprotein lipase (LPL) hydrolyzes chylomicron and very low density lipoprotein (VLDL) triglycerides and potentiates the cellular uptake of lipoproteins. These LPL-lipoprotein associations could involve only protein-lipid interaction, or they could be modulated by apolipoproteins (apo). ApoB is the major protein component of chylomicrons, VLDL, and low density lipoprotein (LDL). ApoB100, a large glycoprotein with a molecular mass of 550 kDa, is composed of several functional domains. A carboxyl-terminal region of the protein is the ligand for the LDL receptor. There are several hydrophobic domains that are believed to be important in lipid binding. The relatively hydrophilic amino-terminal region of apoB, however, has no known function. Using solid phase assays we quantified LPL-lipoprotein complex formation. On a molar basis, severalfold greater amounts of LPL bound to LDL and VLDL than to high density lipoprotein at all the concentrations of LPL tested (0.9-55 nM). To assess the roles of LDL protein versus lipid, we performed competition and ligand blotting experiments. LDL and an amino-terminal fragment of apoB competed better for 125I-LPL binding to LDL than did lipid emulsion particles. Delipidation of LDL-coated plates did not alter LPL binding. On ligand blots, LPL bound to amino-terminal fragments of apoB generated by thrombin digestion but not to apoA1, apoE, or carboxyl-terminal fragments of apoB. Further evidence for LPL interaction with the amino-terminal region of apoB was obtained using anti-apoB monoclonal antibodies. Antibodies directed against the amino-terminal regions of apoB blocked LPL interaction with LDL, whereas those against the carboxyl-terminal region of apoB did not inhibit LPL interaction with LDL. Thus, we conclude that a specific interaction between LPL and the amino-terminal region of apoB may facilitate LPL association with circulating lipoproteins.
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Affiliation(s)
- S Y Choi
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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38
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Edwards IJ, Xu H, Obunike JC, Goldberg IJ, Wagner WD. Differentiated macrophages synthesize a heparan sulfate proteoglycan and an oversulfated chondroitin sulfate proteoglycan that bind lipoprotein lipase. Arterioscler Thromb Vasc Biol 1995; 15:400-9. [PMID: 7749850 DOI: 10.1161/01.atv.15.3.400] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Lipoprotein lipase (LpL), which facilitates lipoprotein uptake by macrophages, associates with the cell surface by binding to proteoglycans (PGs). Studies were designed to identify and characterize specific PGs that serve as receptors for LpL and to examine effects of cell differentiation on LpL binding. PG synthesis was examined by radiolabeling THP-1 monocytes and macrophages (a cell line originally derived from a patient with acute monocytic leukemia) with [35S]sodium sulfate and [3H]serine or [3H]glucosamine. Radiolabeled PGs isolated from the cell surface were purified by chromatography and identified as chondroitin-4-sulfate (CS) PG and heparan sulfate (HS) PG. A sixfold increase in CSPG and an 11-fold increase in HSPG accompanied cell differentiation. Whereas HS glycosaminoglycan chains from both monocytes and macrophages were 7.5 kD in size, CS chains increased in size from 17 kD to 36 kD with cell differentiation, and contained hexuronyl N-acetylgalactosamine-4,6-di-O sulfate disaccharides. LpL binding was sevenfold higher to differentiated cells, and affinity chromatography demonstrated that two cell surface PGs bound to LpL: HSPG and the oversulfated CSPG produced only by differentiated cells. We conclude that differentiation-associated changes in cell surface PG of human macrophages have functional consequences that could increase the atherogenic potential of the cells.
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Affiliation(s)
- I J Edwards
- Wake Forest University, Department of Comparative Medicine, Bowman Gray School of Medicine, Winston-Salem, NC 27157-1040, USA
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39
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Park JW, Oh MS, Yang JY, Park BH, Rho HW, Lim SN, Jhee EC, Kim HR. Glycosylation, dimerization, and heparin affinity of lipoprotein lipase in 3T3-L1 adipocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1254:45-50. [PMID: 7811745 DOI: 10.1016/0005-2760(94)00161-q] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The relationship between glycosylation, dimerization, and heparin affinity of lipoprotein lipase (LPL) was studied in 3T3-L1 adipocytes. Three forms of LPL subunits were found in normal cells; totally endo H-resistant (57 kDa), partially sensitive (54 kDa), and totally sensitive (51 kDa) forms. LPL in normal cells was active, dimeric, and showed high affinity for heparin. LPL in cells treated with tunicamycin, preventing the transfer of N-linked oligosaccharide chain, was unglycosylated (51 kDa) and inactive. LPL proteins were found as an aggregate, and had low affinity for heparin. After treatment with castanospermine, an inhibitor of ER glucosidase I, 80% of LPL activity was inhibited. Most of LPL proteins were totally endo H-sensitive, present as an aggregate, and had low affinity for heparin. LPL in cells treated with deoxymannojirimycin, an inhibitor of Golgi mannosidase I, was active, dimeric, and had high affinity for heparin as in normal cells. But LPL subunits were all endo H-sensitive. These results suggest that core glycosylation and subsequent removal of glucose residue is required, but processing after Golgi mannosidase I is not necessary for dimerization and acquisition of high heparin affinity of LPL.
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Affiliation(s)
- J W Park
- Department of Biochemistry, Chonbuk National University Medical School, Chonju, South Korea
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40
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Fernández-Borja M, Bellido D, Makiya R, David G, Olivecrona G, Reina M, Vilaró S. Actin cytoskeleton of fibroblasts organizes surface proteoglycans that bind basic fibroblast growth factor and lipoprotein lipase. CELL MOTILITY AND THE CYTOSKELETON 1995; 30:89-107. [PMID: 7606810 DOI: 10.1002/cm.970300202] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cell surface proteoglycans participate in molecular events that regulate cell adhesion, migration, and proliferation. To investigate the organization of these molecules at the cell surface, the distribution of two well-known proteoglycan ligands has been studied. These ligands, lipoprotein lipase and basic fibroblast growth factor, showed a characteristic binding pattern consisting of highly organized parallel arrays that crossed the upper surface of human skin fibroblasts. The proteoglycan nature of the binding sites was evident from their susceptibility to heparinases, and from ligand displacement by heparin. Parallel localization of the ligands and actin, and treatment of the cells with cytochalasin, showed that the binding proteoglycans are organized by the actin cytoskeleton. The ligands induced a different behaviour of the binding sites on incubation of the cells at 37 degrees C. Lipoprotein lipase produced a movement of the binding proteoglycans along the actin filaments towards the cell center. In contrast, after binding of basic fibroblast growth factor the binding proteoglycans remained spread over the cell surface and actin depolymerization was induced. Since an increasing number of ligands appear to depend on proteoglycans for their interactions with their high affinity receptors, distribution and movement of proteoglycans at the cell surface that is organized by the actin cytoskeleton could direct and enhance the encounters between the ligands and their specific receptors.
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Affiliation(s)
- M Fernández-Borja
- Department of Biochemistry and Physiology, University of Barcelona, Spain
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41
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Parthasarathy N, Goldberg I, Sivaram P, Mulloy B, Flory D, Wagner W. Oligosaccharide sequences of endothelial cell surface heparan sulfate proteoglycan with affinity for lipoprotein lipase. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31802-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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42
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Transgenic mice expressing human lipoprotein lipase driven by the mouse metallothionein promoter. A phenotype associated with increased perinatal mortality and reduced plasma very low density lipoprotein of normal size. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32233-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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43
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Nevin DN, Brunzell JD, Deeb SS. The LPL gene in individuals with familial combined hyperlipidemia and decreased LPL activity. ARTERIOSCLEROSIS AND THROMBOSIS : A JOURNAL OF VASCULAR BIOLOGY 1994; 14:869-73. [PMID: 8199176 DOI: 10.1161/01.atv.14.6.869] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Familial combined hyperlipidemia (FCHL) is an oligogenic disorder, with family members having elevated apolipoprotein B-100 levels and either elevated plasma cholesterol or triglyceride levels or both. Obligate heterozygous parents of children with lipoprotein lipase (LPL) deficiency express a mild FCHL phenotype. Of patients with FCHL, 36% have diminished postheparin LPL activity and mass values that are comparable with those of obligate heterozygotes for LPL deficiency. It is hypothesized that heterozygosity for mutations in the LPL gene could contribute to FCHL in this subset of patients. Single-strand conformation polymorphism (SSCP) analysis, direct DNA sequencing, and Southern blot analysis were used to examine exons 1 through 9 and exon-intron junctions of the LPL gene in 20 patients with FCHL and low LPL activity and mass. One subject had a substitution (GAC-->AAC) in exon 2, changing Asp9 to Asn. Two subjects had a previously undescribed "silent" substitution (GTG-->GTA) in exon 3 at Val108. Three patients had a premature termination at codon 447 in exon 9 resulting in truncation of the mature protein by two amino acids. In addition to SSCP analysis, exons 4, 5, and 6, where almost all mutations in LPL-deficient patients have been found, were sequenced and no additional mutations were found. Southern blot analysis of the LPL gene revealed one subject with heterozygous loss of an EcoRI site but without an abnormality in Stu I restriction fragments; this mutation is therefore unlikely to be functionally significant. The substitutions identified at codons 9 and 447 have previously been found not to affect lipolytic activity when expressed in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D N Nevin
- Department of Medicine, University of Washington, Seattle 98195
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44
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Patsch W, Sharrett AR, Chen IY, Lin-Lee YC, Brown SA, Gotto AM, Boerwinkle E. Associations of allelic differences at the A-I/C-III/A-IV gene cluster with carotid artery intima-media thickness and plasma lipid transport in hypercholesterolemic-hypertriglyceridemic humans. ARTERIOSCLEROSIS AND THROMBOSIS : A JOURNAL OF VASCULAR BIOLOGY 1994; 14:874-83. [PMID: 8199177 DOI: 10.1161/01.atv.14.6.874] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Individuals with elevated levels of plasma cholesterol and triglyceride may be at higher risk for coronary artery disease than those with isolated elevations of either cholesterol or triglyceride. Sequence variation in the A-I/C-III/A-IV gene cluster has been implicated in the etiology of some disorders associated with premature atherosclerosis and/or hypertriglyceridemias with or without elevations of cholesterol. This led to the hypothesis that allelic variation at this gene locus alters plasma lipid transport and affects susceptibility for atherosclerosis. The study population, from the Atherosclerosis Risk in Communities (ARIC) Study, consisted of 50 normolipidemic individuals, 48 subjects with elevated plasma cholesterol, 47 subjects with elevated plasma triglyceride, and 123 subjects with both elevated plasma cholesterol and triglyceride who were used to evaluate associations between an Xmn I polymorphic site 2.5 kilobase pairs (kbp) upstream of the structural gene for apolipoprotein (apo) A-I, intimal-medial thickening of the extracranial carotid arteries, and several plasma lipid factors. The relative allele frequencies of the 8.3-kbp allele and the 6.6-kbp allele were .86 and .14, respectively, in the entire study population and did not differ among the lipid phenotypes. In the group with elevated plasma cholesterol and triglyceride, subjects possessing the 6.6-kbp allele exhibited a greater carotid artery intimal-medial thickness (P = .034) and higher plasma levels of apoA-I, high-density lipoprotein (HDL) cholesterol, and HDL3 cholesterol (P < .02) than subjects homozygous for the 8.3-kbp allele. In contrast, subjects with the 6.6-kbp allele displayed lower mean ratios of apolipoproteins C-II to C-III, C-II to A-IV and E to A-IV in plasma (P < .05) and a lower mean ratio of apolipoprotein C-II to C-III in the triglyceride-rich lipoproteins (P = .026). Sequence variation in or near the genes encoding apolipoproteins A-I, C-III, and A-IV may therefore identify a group of hypercholesterolemic-hypertriglyceridemic persons who are at higher risk for atherosclerosis than others with the same lipoprotein phenotype.
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Affiliation(s)
- W Patsch
- Department of Medicine, Baylor College of Medicine, Houston, Tex
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45
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Sivaram P, Choi S, Curtiss L, Goldberg I. An amino-terminal fragment of apolipoprotein B binds to lipoprotein lipase and may facilitate its binding to endothelial cells. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36894-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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46
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Williamson DH, Lund P. Cellular mechanisms for the regulation of adipose tissue lipid metabolism in pregnancy and lactation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 352:45-70. [PMID: 7832059 DOI: 10.1007/978-1-4899-2575-6_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- D H Williamson
- Metabolic Research Laboratory, Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford, United Kingdom
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47
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Sasaki A, Sivaram P, Goldberg IJ. Lipoprotein lipase binding to adipocytes: evidence for the presence of a heparin-sensitive binding protein. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 265:E880-8. [PMID: 8279543 DOI: 10.1152/ajpendo.1993.265.6.e880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lipoprotein lipase (LPL) is synthesized by adipocytes, associated with the cell surface, and released from the cells when they are treated with heparin. Release of LPL from the adipocyte is required for LPL to migrate to its physiological site of action on the luminal surface of capillary endothelial cells. To better understand this process, we studied the interaction of LPL with adipocyte cell membrane proteins. With the use of a ligand blot method, LPL specifically bound to a heparin-releasable, 116-kDa protein on mouse-derived brown fat adipose cell (BFC-1 beta) and rat adipocyte membranes. A 116-kDa cell surface protein was metabolically labeled with [35S]methionine and bound to LPL-Sepharose. This suggested that the LPL-binding protein was synthesized by the cells. When BFC-1 beta were treated with heparin to eliminate heparin-sensitive cell surface binding sites, LPL binding to the cells decreased and release of newly synthesized LPL activity increased. 125I-labeled LPL binding to control cells was reduced (> 70%) by a 50-fold excess of unlabeled LPL. The residual LPL binding to heparin-treated cells was, however, not decreased by the addition of unlabeled LPL. These data imply that specific adipocyte surface LPL binding involves heparin-sensitive sites. We hypothesize that the heparin-releasable, 116-kDa LPL-binding protein mediates specific LPL binding to adipocytes and that LPL activity within adipose tissue is regulated, in part, by the interaction of LPL with this binding protein.
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Affiliation(s)
- A Sasaki
- Department of Medicine and Specialized Center of Research in Arteriosclerosis, Columbia University College of Physicians and Surgeons, New York, New York 10032
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48
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Stins MF, Sivaram P, Sasaki A, Goldberg IJ. Specificity of lipoprotein lipase binding to endothelial cells. J Lipid Res 1993. [DOI: 10.1016/s0022-2275(20)35103-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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49
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Ihrcke NS, Wrenshall LE, Lindman BJ, Platt JL. Role of heparan sulfate in immune system-blood vessel interactions. IMMUNOLOGY TODAY 1993; 14:500-5. [PMID: 8274190 DOI: 10.1016/0167-5699(93)90265-m] [Citation(s) in RCA: 151] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Heparan sulfate proteoglycan, a component of endothelial cell membranes and extracellular matrices, is involved in a number of the critical functions of endothelium and of antigen-presenting cells. This review discusses how heparan sulfate is released from endothelial cells during inflammation, how the loss of heparan sulfate potentially alters endothelial cell physiology, and how the presence of heparan sulfate in a soluble form might regulate the functioning of lymphocytes at sites of inflammation.
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Affiliation(s)
- N S Ihrcke
- Dept of Surgery, Duke University, Durham, NC 27710
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50
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Enerbäck S, Gimble JM. Lipoprotein lipase gene expression: physiological regulators at the transcriptional and post-transcriptional level. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1169:107-25. [PMID: 8343535 DOI: 10.1016/0005-2760(93)90196-g] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- S Enerbäck
- Department of Molecular Biology, University of Göteborg, Sweden
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