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Zhang Y, Cui L. Discovery and development of small-molecule heparanase inhibitors. Bioorg Med Chem 2023; 90:117335. [PMID: 37257254 PMCID: PMC10884955 DOI: 10.1016/j.bmc.2023.117335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/08/2023] [Accepted: 05/12/2023] [Indexed: 06/02/2023]
Abstract
Heparanase-1 (HPSE) is a promising yet challenging therapeutic target. It is the only known enzyme that is responsible for cleavage of heparan sulfate (HS) side chains from heparan sulfate proteoglycans (HSPGs), and is the key enzyme involved in the remodeling and degradation of the extracellular matrix (ECM). Overexpression of HPSE is found in various types of diseases, including cancers, inflammations, diabetes, and viral infections. Inhibiting HPSE can restore ECM functions and integrity, making the development of HPSE inhibitors a highly sought-after topic. So far, all HPSE inhibitors that have entered clinical trials belong to the category of HS mimetics, and no small-molecule or drug-like HPSE inhibitors have made similar progress. None of the HS mimetics have been approved as drugs, with some clinical trials discontinued due to poor bioavailability, side effects, and unfavorable pharmacokinetics characteristics. Small-molecule HPSE inhibitors are, therefore, particularly appealing due to their drug-like characteristics. Advances in the chemical spaces and drug design technologies, including the increasing use of in vitro and in silico screening methods, have provided new opportunities in drug discovery. This article aims to review the discovery and development of small-molecule HPSE inhibitors via screening strategies to shed light on the future endeavors in the development of novel HPSE inhibitors.
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Affiliation(s)
- Yuzhao Zhang
- Department of Medicinal Chemistry, College of Pharmacy, UF Health Science Center, UF Health Cancer Center, University of Florida, Gainesville, FL 32610, USA
| | - Lina Cui
- Department of Medicinal Chemistry, College of Pharmacy, UF Health Science Center, UF Health Cancer Center, University of Florida, Gainesville, FL 32610, USA.
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Hsieh LTH, Hall BS, Newcombe J, Mendum TA, Umrania Y, Deery MJ, Shi WQ, Salguero FJ, Simmonds RE. Mycolactone causes catastrophic Sec61-dependent loss of the endothelial glycocalyx and basement membrane: a new indirect mechanism driving tissue necrosis in Mycobacterium ulcerans infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.529382. [PMID: 36865118 PMCID: PMC9980099 DOI: 10.1101/2023.02.21.529382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The drivers of tissue necrosis in Mycobacterium ulcerans infection (Buruli ulcer disease) have historically been ascribed solely to the directly cytotoxic action of the diffusible exotoxin, mycolactone. However, its role in the clinically-evident vascular component of disease aetiology remains poorly explained. We have now dissected mycolactone's effects on primary vascular endothelial cells in vitro and in vivo. We show that mycolactone-induced changes in endothelial morphology, adhesion, migration, and permeability are dependent on its action at the Sec61 translocon. Unbiased quantitative proteomics identified a profound effect on proteoglycans, driven by rapid loss of type II transmembrane proteins of the Golgi, including enzymes required for glycosaminoglycan (GAG) synthesis, combined with a reduction in the core proteins themselves. Loss of the glycocalyx is likely to be of particular mechanistic importance, since knockdown of galactosyltransferase II (beta-1,3-galactotransferase 6; B3Galt6), the GAG linker-building enzyme, phenocopied the permeability and phenotypic changes induced by mycolactone. Additionally, mycolactone depleted many secreted basement membrane components and microvascular basement membranes were disrupted in vivo. Remarkably, exogenous addition of laminin-511 reduced endothelial cell rounding, restored cell attachment and reversed the defective migration caused by mycolactone. Hence supplementing mycolactone-depleted extracellular matrix may be a future therapeutic avenue, to improve wound healing rates.
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Affiliation(s)
| | - Belinda S Hall
- Dept of Microbial Sciences, School of Bioscience and Medicine, University of Surrey
| | - Jane Newcombe
- Dept of Microbial Sciences, School of Bioscience and Medicine, University of Surrey
| | - Tom A Mendum
- Dept of Microbial Sciences, School of Bioscience and Medicine, University of Surrey
| | - Yagnesh Umrania
- Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK
| | - Michael J Deery
- Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK
| | - Wei Q Shi
- Department of Chemistry, Ball State University, Muncie, IN 47306, USA
| | | | - Rachel E Simmonds
- Dept of Microbial Sciences, School of Bioscience and Medicine, University of Surrey
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Maccarana M, Tykesson E, Pera EM, Gouignard N, Fang J, Malmström A, Ghiselli G, Li JP. Inhibition of iduronic acid biosynthesis by ebselen reduces glycosaminoglycan accumulation in mucopolysaccharidosis type I fibroblasts. Glycobiology 2021; 31:1319-1329. [PMID: 34192316 PMCID: PMC8600295 DOI: 10.1093/glycob/cwab066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/08/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
Mucopolysaccharidosis type I (MPS-I) is a rare lysosomal storage disorder caused by deficiency of the enzyme alpha-L-iduronidase, which removes iduronic acid in both chondroitin/dermatan sulfate (CS/DS) and heparan sulfate (HS) and thereby contributes to the catabolism of glycosaminoglycans (GAGs). To ameliorate this genetic defect, the patients are currently treated by enzyme replacement and bone marrow transplantation, which have a number of drawbacks. This study was designed to develop an alternative treatment by inhibition of iduronic acid formation. By screening the Prestwick drug library, we identified ebselen as a potent inhibitor of enzymes that produce iduronic acid in CS/DS and HS. Ebselen efficiently inhibited iduronic acid formation during CS/DS synthesis in cultured fibroblasts. Treatment of MPS-I fibroblasts with ebselen not only reduced accumulation of CS/DS but also promoted GAG degradation. In early Xenopus embryos, this drug phenocopied the effect of downregulation of DS-epimerase 1, the main enzyme responsible for iduronic production in CS/DS, suggesting that ebselen inhibits iduronic acid production in vivo. However, ebselen failed to ameliorate the CS/DS and GAG burden in MPS-I mice. Nevertheless, the results propose a potential of iduronic acid substrate reduction therapy for MPS-I patients.
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Affiliation(s)
- Marco Maccarana
- Department of Medical Biochemistry and Microbiology, BMC B11, Uppsala University, Husargatan 3 Box 582 751 23 Uppsala, Sweden
- Department of Experimental Medical Science, BMC C12, Lund University, BMC H11, 221 84 Lund, Sweden
| | - Emil Tykesson
- Department of Experimental Medical Science, BMC C12, Lund University, BMC H11, 221 84 Lund, Sweden
| | - Edgar M Pera
- Department of Laboratory Medicine, Lund Stem Cell Center, Lund University, BMC H11, 221 84 Lund, Sweden
| | - Nadège Gouignard
- Department of Laboratory Medicine, Lund Stem Cell Center, Lund University, BMC H11, 221 84 Lund, Sweden
| | - Jianping Fang
- GlycoNovo Technologies Co., Ltd., Shanghai 201203, China
| | - Anders Malmström
- Department of Experimental Medical Science, BMC C12, Lund University, BMC H11, 221 84 Lund, Sweden
| | - Giancarlo Ghiselli
- Glyconova Srl, Parco Scientifico Silvano Fumero, Bioindustry Park Silvano Fumero S.p.A Via Ribes, 5 - 10010 - Colleretto Giacosa (TO), Italy
| | - Jin-ping Li
- Department of Medical Biochemistry and Microbiology, BMC B11, Uppsala University, Husargatan 3 Box 582 751 23 Uppsala, Sweden
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Ulaganathan T, Shi R, Yao D, Gu RX, Garron ML, Cherney M, Tieleman DP, Sterner E, Li G, Li L, Linhardt RJ, Cygler M. Conformational flexibility of PL12 family heparinases: structure and substrate specificity of heparinase III from Bacteroides thetaiotaomicron (BT4657). Glycobiology 2016; 27:176-187. [PMID: 27621378 DOI: 10.1093/glycob/cww096] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/05/2016] [Accepted: 09/06/2016] [Indexed: 01/19/2023] Open
Abstract
Glycosaminoglycans (GAGs) are linear polysaccharides comprised of disaccharide repeat units, a hexuronic acid, glucuronic acid or iduronic acid, linked to a hexosamine, N-acetylglucosamine (GlcNAc) or N-acetylgalactosamine. GAGs undergo further modification such as epimerization and sulfation. These polysaccharides are abundant in the extracellular matrix and connective tissues. GAGs function in stabilization of the fibrillar extracellular matrix, control of hydration, regulation of tissue, organism development by controlling cell cycle, cell behavior and differentiation. Niche adapted bacteria express enzymes called polysaccharide lyases (PL), which degrade GAGs for their nutrient content. PL have been classified into 24 sequence-related families. Comparison of 3D structures of the prototypic members of these families allowed identification of distant evolutionary relationships between lyases that were unrecognized at the sequence level, and identified occurrences of convergent evolution. We have characterized structurally and enzymatically heparinase III from Bacteroides thetaiotaomicron (BtHepIII; gene BT4657), which is classified within the PL12 family. BtHepIII is a 72.5 kDa protein. We present the X-ray structures of two crystal forms of BtHepIII at resolution 1.8 and 2.4 Å. BtHepIII contains two domains, the N-terminal α-helical domain forming a toroid and the C-terminal β-sheet domain. Comparison with recently determined structures of two other heparinases from the same PL12 family allowed us to identify structural flexibility in the arrangement of the domains indicating open-close movement. Based on comparison with other GAG lyases, we identified Tyr301 as the main catalytic residue and confirmed this by site-directed mutagenesis. We have characterized substrate preference of BtHepIII toward sulfate-poor heparan sulfate substrate.
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Affiliation(s)
| | - Rong Shi
- Département de Biochimie, de Microbiologie et de Bio-informatique, PROTEO, and Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Pavillon Charles-Eugène-Marchand, Québec City, QC G1V 0A6, Canada
| | - Deqiang Yao
- National Center for Protein Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai 201204, China
| | - Ruo-Xu Gu
- Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4, Canada H4P 2R2, Canada
| | - Marie-Line Garron
- the Architecture et Fonction des Macromolécules Biologiques, UMR7257 CNRS, Aix-Marseille University, F-13288 Marseille, France, the INRA, USC1408 Architecture et Fonction des Macromolécules Biologiques, F-13288 Marseille, France
| | - Maia Cherney
- Department of Biochemistry, University of Saskatchewan, Saskatoon, S7N 5E5 Saskatchewan, Canada
| | - D Peter Tieleman
- Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4, Canada H4P 2R2, Canada
| | - Eric Sterner
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Guoyun Li
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Lingyun Li
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Robert J Linhardt
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, Saskatoon, S7N 5E5 Saskatchewan, Canada
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Catalytic and substrate promiscuity: distinct multiple chemistries catalysed by the phosphatase domain of receptor protein tyrosine phosphatase. Biochem J 2016; 473:2165-77. [PMID: 27208174 DOI: 10.1042/bcj20160289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/16/2016] [Indexed: 02/04/2023]
Abstract
The presence of latent activities in enzymes is posited to underlie the natural evolution of new catalytic functions. However, the prevalence and extent of such substrate and catalytic ambiguity in evolved enzymes is difficult to address experimentally given the order-of-magnitude difference in the activities for native and, sometimes, promiscuous substrate/s. Further, such latent functions are of special interest when the activities concerned do not fall into the domain of substrate promiscuity. In the present study, we show a special case of such latent enzyme activity by demonstrating the presence of two mechanistically distinct reactions catalysed by the catalytic domain of receptor protein tyrosine phosphatase isoform δ (PTPRδ). The primary catalytic activity involves the hydrolysis of a phosphomonoester bond (C─O─P) with high catalytic efficiency, whereas the secondary activity is the hydrolysis of a glycosidic bond (C─O─C) with poorer catalytic efficiency. This enzyme also displays substrate promiscuity by hydrolysing diester bonds while being highly discriminative for its monoester substrates. To confirm these activities, we also demonstrated their presence on the catalytic domain of protein tyrosine phosphatase Ω (PTPRΩ), a homologue of PTPRδ. Studies on the rate, metal-ion dependence, pH dependence and inhibition of the respective activities showed that they are markedly different. This is the first study that demonstrates a novel sugar hydrolase and diesterase activity for the phosphatase domain (PD) of PTPRδ and PTPRΩ. This work has significant implications for both understanding the evolution of enzymatic activity and the possible physiological role of this new chemistry. Our findings suggest that the genome might harbour a wealth of such alternative latent enzyme activities in the same protein domain that renders our knowledge of metabolic networks incomplete.
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Wu L, Viola CM, Brzozowski AM, Davies GJ. Structural characterization of human heparanase reveals insights into substrate recognition. Nat Struct Mol Biol 2015; 22:1016-22. [PMID: 26575439 PMCID: PMC5008439 DOI: 10.1038/nsmb.3136] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 11/09/2015] [Indexed: 12/13/2022]
Abstract
Heparan sulfate (HS) is a glycosaminoglycan that forms a key component of the extracellular matrix (ECM). Breakdown of HS is carried out by heparanase (HPSE), an endo-β-glucuronidase of the glycoside hydrolase 79 (GH79) family. Overexpression of HPSE results in breakdown of extracellular HS and release of stored growth factors and hence is strongly linked to cancer metastasis. Here we present crystal structures of human HPSE at 1.6-Å to 1.9-Å resolution that reveal how an endo-acting binding cleft is exposed by proteolytic activation of latent proHPSE. We used oligosaccharide complexes to map the substrate-binding and sulfate-recognition motifs. These data shed light on the structure and interactions of a key enzyme involved in ECM maintenance and provide a starting point for the design of HPSE inhibitors for use as biochemical tools and anticancer therapeutics.
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Affiliation(s)
- Liang Wu
- Department of Chemistry, University of York, York, UK
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7
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Abstract
Dengue viruses (DEN) cause a broad spectrum of clinical manifestations including potentially life-threatening conditions such as hemorrhagic shock syndrome and less frequently acute hepatitis with liver failure and encephalopathy. In addition, dengue viruses provide a potential model to understand the initiation of hepatocyte infection by the structurally closely related hepatitis C virus (HCV), because this virus at present cannot be grown in cell culture. Although the initial steps of viral infection are a critical determinant of tissue tropism and therefore pathogenesis, little is known about the molecular basis of binding and endocytic trafficking of DEN or of any other flavivirus. Our studies revealed that binding of radiolabeled DEN to the human hepatoma cell line HuH-7 was strictly pH dependent and substantially inhibitable by the glycosaminoglycan heparin. Ligand-blot analysis, performed as a viral overlay assay, showed two heparan sulfate (HS) containing cell-surface binding proteins resolving at 33 and 37 kd. Based on the sensitivity of unprotected virus and the viral binding site on the cell surface to trypsin, viral internalization was quantified as an increase in trypsin protected virus over time. Virus trafficking to the site of degradation was inhibited by pH dissociation of the clathrin coat and dependent on IP(3)-mediated homotypic endosomal fusion. These findings confirm the hypothesis that binding and internalization of DEN by hepatocytes are mediated primarily by HS containing proteoglycans and suggest that flaviviruses traffic the major clathrin-dependent endocytic pathway during infection.
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Affiliation(s)
- P Hilgard
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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9
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Miller JD, Cummings J, Maresh GA, Walker DG, Castillo GM, Ngo C, Kimata K, Kinsella MG, Wight TN, Snow AD. Localization of perlecan (or a perlecan-related macromolecule) to isolated microglia in vitro and to microglia/macrophages following infusion of beta-amyloid protein into rodent hippocampus. Glia 1997; 21:228-43. [PMID: 9336237 DOI: 10.1002/(sici)1098-1136(199710)21:2<228::aid-glia6>3.0.co;2-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The origin of the heparan sulfate proteoglycan (PG), perlecan, in beta-amyloid protein (A beta)-containing amyloid deposits in Alzheimer's disease (AD) brain is not known. In the present investigation we used indirect immunofluorescence, SDS-PAGE, and Western blotting with a specific perlecan core protein antibody to identify possible cell candidates of perlecan production in both primary cell cultures and in a rat infusion model. Double and triple-labeled indirect immunofluorescence was performed on dissociated primary rat septal cultures using antibodies for specific identification of cell types and for perlecan core protein. In mixed cultures of both embryonic day 18 (containing neurons and glia) and postnatal day 2-3 (devoid of neurons), microglia identified by labeling with OX-42 or anti-ED1 were the only cell type also double labeled with an affinity-purified polyclonal antibody against perlecan core protein. Similar immunolabeling of microglia with the anti-perlecan antibody was also observed in purified cultures of post-natal rat microglia. Analyses of PGs from cultured postnatal rat microglia by Western blotting using a polyclonal antibody against perlecan core protein revealed an approximately 400 kDa band in cell layer, which was intensified following heparitinase/heparinase digestion, suggestive of perlecan core protein. Other lower Mr bands were also found implicating either degradation of the 400 kDa core protein or the presence of separate and distinct gene products immunologically related to perlecan. Reverse transcription followed by polymerase chain reaction using human perlecan domain I specific primers demonstrated perlecan mRNA in cultured human microglia derived from postmortem normal aged and AD brain. Following a 1-week continuous infusion of A beta (1-40) into rodent hippocampus, immunoperoxidase immunocytochemistry and double-labeled immunofluorescent studies revealed perlecan accumulation primarily localized to microglia/macrophages within the A beta infusion site. These studies have identified microglia/macrophages as one potential source of perlecan (or a perlecan-related macromolecule) which may be important for the ongoing accumulation of both perlecan and A beta in the amyloid deposits of AD.
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Affiliation(s)
- J D Miller
- Department of Pathology, University of Washington, Seattle 98195-6480, USA
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11
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Hendriks WL, van der Boom H, van Vark LC, Havekes LM. Lipoprotein lipase stimulates the binding and uptake of moderately oxidized low-density lipoprotein by J774 macrophages. Biochem J 1996; 314 ( Pt 2):563-8. [PMID: 8670071 PMCID: PMC1217086 DOI: 10.1042/bj3140563] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Lipoprotein lipase (LPL) stimulates the uptake of low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) in different cell types, including macrophages, through bridging of LPL between lipoproteins and extracellular heparan sulphate proteoglycans (HSPG). Because macrophages produce LPL and because modified lipoproteins are present in the arterial wall in vivo, we wondered whether LPL also enhances the uptake of oxidized LDL by J774 macrophages. LDL samples with different degrees of oxidation, as evaluated by relative electrophoretic mobility (REM) as compared with native LDL are used as well as native and acetylated LDL. Addition of 5 microg/ml LPL to the J774 cell culture medium stimulated the binding of both native LDL and moderately oxidized LDL (REM < 3.5) 50-100-fold, and their uptake was stimulated approx. 20-fold. The LPL-mediated binding of native LDL and moderately oxidized LDL was dose-dependent. Preincubation of the cells with heparinase (2.4 units/ml) inhibited the stimulatory effect of LPL, indicating that this LPL-mediated stimulation was due to bridging between the lipoproteins and HSPG. The binding to J774 macrophages of severely oxidized LDL (REM=4.3) was stimulated less than 3-fold by LPL, whereas its uptake was not stimulated significantly. The binding and uptake of acetylated LDL (AcLDL) were not stimulated by LPL, although the LPL-molecule itself does bind to AcLDL. Measurements of the cellular lipid content showed that addition of LPL also stimulated the accumulation in the cells of cholesteryl ester derived from both native LDL and moderately oxidized LDL in a dose-dependent manner. We conclude that our results present experimental evidence for the hypothesis that LPL serves as an atherogenic component in the vessel wall.
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Affiliation(s)
- W L Hendriks
- TNO-Prevention and Health, Gaubius Laboratory, Leiden, The Netherlands, USA
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Williams KJ, Tabas I. The response-to-retention hypothesis of early atherogenesis. Arterioscler Thromb Vasc Biol 1995; 15:551-61. [PMID: 7749869 PMCID: PMC2924812 DOI: 10.1161/01.atv.15.5.551] [Citation(s) in RCA: 922] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- K J Williams
- Division of Endocrinology and Metabolic Diseases, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA
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Stein O, Ben-Naim M, Dabach Y, Hollander G, Stein Y. Murine macrophages secrete factors that enhance uptake of non-lipoprotein [3H]cholesteryl ester by aortic smooth muscle cells. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1212:305-10. [PMID: 8199201 DOI: 10.1016/0005-2760(94)90204-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have recently demonstrated that macrophage conditioned medium (MP medium) and beta VLDL enhance cholesterol esterification in cultured aortic smooth muscle cells by LDL receptor mediated and other pathways (Stein, O. et al. (1993) Arteroscl. Thromb. 13, 1350-1358). In view of the presence of extracellular non-lipoprotein cholesteryl ester (in the form of lipid droplets) in the atheroma, the effect of MP medium on the cellular uptake of liposomal cholesteryl linoleyl ether (CLE) or cholesteryl ester (CE) was studied. After 4 h incubation in MP medium, the uptake of liposomal [3H]CLE was up to 10-fold higher than in the presence of control medium of the same composition but not conditioned with macrophages (DV medium). Similar results were seen also with HSF derived from LDL receptor negative donors. The MP medium-stimulated uptake of liposomal [3H]CE resulted also in hydrolysis of 70-90% of the labeled compound, indicating that the [3H]CE was intracellular. While the MP medium effect on liposomal [3H]CLE uptake was evident after 4 h, its effect on [3H]cholesterol esterification by SMC in the presence of beta VLDL could be demonstrated only after 24 h. Addition of apoE to MP medium resulted in a small (30-40%) increase in the uptake of liposomal [3H]CLE; however, it was augmented more than 4-fold when apoE was added to DV medium. The MP medium effect on the uptake of liposomal [3H]CLE was interfered with by heparin, anti-LPL antibody or heparinase, while these treatments did not affect [3H]cholesterol esterification in the presence of beta VLDL. These results suggest that the interaction between SMC and two potential sources of lipids in atheroma, i.e., lipoproteins and non-lipoprotein lipid droplets, could be governed by different components of the MP medium. In the case of the lipid droplets, as modeled here in the form of liposomes, macrophage-derived lipoprotein lipase could play a major role in cholesteryl ester transfer into SMC.
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Affiliation(s)
- O Stein
- Department of Experimental Medicine and Cancer Research, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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14
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Secretion-capture role for apolipoprotein E in remnant lipoprotein metabolism involving cell surface heparan sulfate proteoglycans. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42009-6] [Citation(s) in RCA: 156] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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15
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Snow AD, Sekiguchi R, Nochlin D, Fraser P, Kimata K, Mizutani A, Arai M, Schreier WA, Morgan DG. An important role of heparan sulfate proteoglycan (Perlecan) in a model system for the deposition and persistence of fibrillar A beta-amyloid in rat brain. Neuron 1994; 12:219-34. [PMID: 8292358 DOI: 10.1016/0896-6273(94)90165-1] [Citation(s) in RCA: 249] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A consistent rat model for the study of the consequences of congophilic and fibrillar A beta-amyloid in brain has been developed. One hundred percent of animals receiving infusions of synthetic beta-amyloid protein (A beta 1-40) plus a specific heparan sulfate proteoglycan (HSPG) for 1 week or 7 weeks (following 2 week infusions) demonstrated Congo red and thioflavin S-positive deposits adjacent to the infusion site. Extracellular amyloid fibrils were identified by electron microscopy and were immunogold decorated with A beta antibody. Significant increases in Congo red staining were observed in animals infused with A beta plus HSPG versus those infused with only A beta. Infusion of A beta alone was variable with respect to congophilic amyloid persistence, which occurred in 50% of animals and only when endogenous HSPGs accumulated at A beta deposition sites. By 7 weeks, only animals infused with A beta plus HSPG demonstrated compaction of the Congo red material from amorphous, wispy deposits (at 1 week) to stellate deposits resembling a Maltese cross. These spherical amyloid deposits were very similar to Congo red-stained amyloid plaques in human Alzheimer's disease brain, and in vitro data suggest that they were probably formed in vivo following interactions with endogenous brain components.
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Affiliation(s)
- A D Snow
- Department of Pathology, University of Washington, Seattle 98195
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Tabas I, Li Y, Brocia R, Xu S, Swenson T, Williams K. Lipoprotein lipase and sphingomyelinase synergistically enhance the association of atherogenic lipoproteins with smooth muscle cells and extracellular matrix. A possible mechanism for low density lipoprotein and lipoprotein(a) retention and macrophage foam cell formation. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80745-5] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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17
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Vijayagopal P. Enhanced synthesis and accumulation of proteoglycans in cholesterol-enriched arterial smooth muscle cells. Biochem J 1993; 294 ( Pt 2):603-11. [PMID: 8373376 PMCID: PMC1134498 DOI: 10.1042/bj2940603] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To determine the effects of lipid accumulation on proteoglycan synthesis, we studied proteoglycan biosynthesis in rabbit aortic smooth muscle cells in culture. Cholesterol-enrichment was accomplished by incubating confluent smooth muscle cells with cationized low-density lipoprotein. Control and cholesterol-enriched cells were incubated with [35S]sulphate, [3H]glucosamine, or [3H]serine. Metabolically labelled proteoglycans in the cell layer and medium were quantified. During a 20 h incubation period, proteoglycan synthesis in cholesterol-enriched cells increased by 40-50% above that in control cells. A similar increase in precursor incorporation into proteoglycans was also noted following a short 15 min pulse. The cholesterol-enriched cells also showed a 45-50% increase over control rates in the intralysosomal accumulation of a large chondroitin sulphate proteoglycan and a small dermatan sulphate proteoglycan. The enhanced synthesis of proteoglycans in cholesterol-enriched cultures was inhibited by cycloheximide and actinomycin D, which are inhibitors of protein synthesis and transcription respectively. Proteoglycan turnover was investigated by pulse-chase analysis. Following a 2-h pulse, intracellular proteoglycans in cholesterol-enriched cells disappeared, having a half-life of 26.5 h compared with 2.8 h for those in the control cells. The amount of trypsin-releasable proteoglycan was significantly reduced in cholesterol-enriched cells. In addition, the degradation of proteoglycans was severely retarded in cholesterol-enriched cultures. The activities of three acid hydrolases, N-acetyl-beta-hexosaminidase, beta-glucuronidase and cathepsin C, were significantly reduced in cholesterol-enriched cells compared with activities in control cells. The results indicate that proteoglycan metabolism is altered in cholesterol-enriched smooth muscle cells.
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Affiliation(s)
- P Vijayagopal
- Department of Medicine and Anatomy, Louisiana State University Medical Center, New Orleans
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Mulder M, Lombardi P, Jansen H, van Berkel T, Frants R, Havekes L. Low density lipoprotein receptor internalizes low density and very low density lipoproteins that are bound to heparan sulfate proteoglycans via lipoprotein lipase. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)98359-6] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Rumsey SC, Obunike JC, Arad Y, Deckelbaum RJ, Goldberg IJ. Lipoprotein lipase-mediated uptake and degradation of low density lipoproteins by fibroblasts and macrophages. J Clin Invest 1992; 90:1504-12. [PMID: 1401083 PMCID: PMC443197 DOI: 10.1172/jci116018] [Citation(s) in RCA: 153] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Lipoprotein lipase (LPL), the rate limiting enzyme for hydrolysis of lipoprotein triglyceride, also mediates nonenzymatic interactions between lipoproteins and heparan sulfate proteoglycans. To determine whether cell surface LPL increases LDL binding to cells, bovine milk LPL was added to upregulated and nonupregulated human fibroblasts along with media containing LDL. LDL binding to cells was increased 2-10-fold, in a dose-dependent manner, by the addition of 0.5-10 micrograms/ml of LPL. The amount of LDL bound to the cells in the presence of LPL far exceeded the capacity for LDL binding via the LDL receptor. Treatment of fibroblasts with heparinase and heparitinase resulted in a 64% decrease in LPL-mediated LDL binding. Compared to studies performed without LPL, more LDL was internalized and degraded in the presence of LPL, but the time course was slower than that of classical lipoprotein receptor mediated pathways. In LDL receptor negative fibroblasts, LPL increased surface bound LDL > 140-fold, intracellular LDL > 40-fold, and LDL degradation > 6-fold. These effects were almost completely inhibited by heparin and anti-LPL monoclonal antibody. LPL also increased the binding and uptake by fibroblasts of apolipoprotein-free triglyceride emulsions; binding was increased > 8-fold and cellular uptake was increased > 40-fold with LPL. LPL increased LDL binding to THP-1 monocytes, and increased LDL uptake (4.5-fold) and LDL degradation (2.5-fold) by THP-1 macrophages. In the absence of added LPL, heparin and anti-LPL monoclonal antibodies decreased LDL degradation by > 40%, and triglyceride emulsion uptake by > 50%, suggesting that endogenously produced LPL mediated lipid particle uptake and degradation. We conclude that LPL increases lipid and lipoprotein uptake by cells via a pathway not involving the LDL receptor. This pathway may be important for lipid accumulation in LPL synthesizing cells.
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Affiliation(s)
- S C Rumsey
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York 10032
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