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Rinninger F, Brundert M, Budzinski RM, Fruchart JC, Greten H, Castro GR. Scavenger receptor BI (SR-BI) mediates a higher selective cholesteryl ester uptake from LpA-I compared with LpA-I:A-II lipoprotein particles. Atherosclerosis 2003; 166:31-40. [PMID: 12482548 DOI: 10.1016/s0021-9150(02)00311-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Scavenger receptor class B, type I (SR-BI) mediates the selective uptake of high-density lipoprotein- (HDL-) associated cholesteryl esters (CE), i.e. lipid uptake independent from HDL holo-particle internalisation. This pathway contributes to the HDL-mediated CE delivery to the liver. From human plasma HDL, two major lipoprotein subfractions can be isolated: one contains apolipoprotein (apo) A-I and apo A-II (LpA-I:A-II) as dominant protein components, whereas in the other population apo A-II is absent (LpA-I). In this investigation the role of SR-BI in selective CE uptake from HDL, LpA-I and LpA-I:A-II was explored. HDL(3) (d=1.125-1.21 g/ml), LpA-I and LpA-I:A-II were isolated from human plasma and radiolabeled in the protein (125I) as well as in the CE moiety ([3H]). Baby hamster kidney (BHK) cells were stably transfected with the full-length human SR-BI cDNA and these cells demonstrate SR-BI expression in immunoblots. In contrast, no SR-BI protein was detectable in control BHK cells (vector). To investigate lipoprotein uptake, cells incubated (37 degrees C, 4 h) in medium containing radiolabeled HDL(3), LpA-I or LpA-I:A-II and finally cellular tracer content was determined. For both types of BHK cells, the rate of apparent lipoprotein particle uptake according to the lipid tracer ([3H]) was in substantial excess over that due to the protein tracer (125I) demonstrating selective CE uptake ([3H]-(125)I) from HDL(3), LpA-I and LpA-I:A-II. SR-BI expression increased cellular selective CE uptake from labeled HDL(3) up to 24-fold. In BHK cells without SR-BI expression, selective CE uptake was higher from LpA-I compared with LpA-I:A-II. Analogously, in BHK cells with SR-BI expression, the rate of selective CE uptake was higher from LpA-I compared with LpA-I:A-II. In summary, SR-BI significantly increases selective CE uptake from HDL(3), LpA-I and LpA-I:A-II. Concerning HDL subfractions, the rate of SR-BI-mediated selective CE uptake is greater from LpA-I compared with LpA-I:A-II and this result suggests that SR-BI preferentially facilitates the CE transfer from LpA-I lipoprotein particles to cells.
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Affiliation(s)
- Franz Rinninger
- Zentrum fuer Innere Medizin, Universitaetsklinikum Hamburg-Eppendorf, Universitaet Hamburg, Martinistrasse 52, 20246 Hamburg, Germany.
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2
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Hayat S, Raynes JG. Acute phase serum amyloid A protein increases high density lipoprotein binding to human peripheral blood mononuclear cells and an endothelial cell line. Scand J Immunol 2000; 51:141-6. [PMID: 10652160 DOI: 10.1046/j.1365-3083.2000.00661.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serum Amyloid A (SAA) is an acute-phase protein secreted mainly by hepatocytes and is largely associated with high-density lipoprotein (HDL) in plasma. It has been suggested that SAA alters HDL binding to the cell surface and that this in turn changes HDL-mediated cholesterol delivery to cells. Incorporation of SAA into HDL at concentrations equivalent to those found physiologically in moderate inflammation mediated a 1.5-fold increase in the binding of HDL to adherent peripheral blood mononuclear cells but had no effect on binding of the lipoprotein to the monocyte cell lines, U937 or THP-1. SAA incorporation also increased binding to an endothelial cell line, EA.hy.926. Hepatoma cells (HuH-7) showed no change in specific binding of the SAA-enriched HDL particle compared to normal HDL. These results suggest that a specific receptor for HDL-bound SAA is found on differentiated human macrophages and an endothelial cell line, which may have functional significance in lipid metabolism or other macrophage responses during inflammation.
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Affiliation(s)
- S Hayat
- Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St., London WC1E 7HT, UK
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3
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Abstract
High-density lipoprotein (HDL), the most abundant human plasma lipoprotein, plays a major role in reverse cholesterol transport, which recycles cholesterol from peripheral cells to the liver. HDL constitutes a heterogeneous group of particles differing in density, size, electrophoretic mobility, and apolipoprotein content. HDL can therefore be fractionated into discrete subclasses by different techniques according to their physicochemical properties. The clinical significance of HDL differs with the subclasses, especially with respect to coronary heart disease, alcohol intake, longevity, dyslipoproteinemia, dietary fat content, and hypolipidemic drugs. Because of their structural and functional diversity, HDL subclasses generate considerable hope that they may help to improve the identification of individuals at an increased risk of developing coronary heart disease.
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Affiliation(s)
- A Tailleux
- SERLIA-INSERM U325, Institut Pasteur, Lille
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4
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Huang Y, von Eckardstein A, Wu S, Assmann G. Cholesterol efflux, cholesterol esterification, and cholesteryl ester transfer by LpA-I and LpA-I/A-II in native plasma. Arterioscler Thromb Vasc Biol 1995; 15:1412-8. [PMID: 7670956 DOI: 10.1161/01.atv.15.9.1412] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
HDLs encompass structurally heterogeneous particles that fulfill specific functions in reverse cholesterol transport. Two-dimensional nondenaturing polyacrylamide gradient gel electrophoresis (2D-PAGGE) of normal plasma and subsequent immunoblotting with anti-apolipoprotein (apo) A-I antibodies differentiates an abundant particle with electrophoretic alpha-mobility and less abundant particles with electrophoretic pre-beta-mobility (pre beta 1-LpA-I, pre beta 2-LpA-I, pre beta 3-LpA-I). Immunodetection with anti-apoA-II antibodies identifies a single particle with alpha-mobility. To differentiate alpha-migrating HDL without apo A-II (alpha-LpA-I) from those with apoA-II (alpha-LpA-I/A-II), we combined 2D-PAGGE with immunoadsorption of apoA-II. Incubation of plasma with [3H]cholesterol-labeled fibroblasts in combination with immunosubtracting 2D-PAGGE allowed us to analyze the role of alpha-LpA-I and alpha-LpA-I/A-II in the uptake and esterification of cell-derived cholesterol in native plasma. Depending on the duration of incubations with cells, alpha-LpA-I took up two to four times more [3H]cholesterol than alpha-LpA-I/A-II. Irrespective of the duration of incubation, two to three times more [3H]cholesteryl esters accumulated in alpha-LpA-I than in alpha-LpA-I/A-II. Subsequent incubations in the presence of an inhibitor of lecithin:cholesterol acyltransferase led to preferential accumulation of [3H]cholesteryl esters in alpha-LpA-I/A-II. In conclusion, our data indicate that alpha-LpA-I is more effective than alpha-LpA-I/A-II in both uptake and esterification of cell-derived cholesterol. Moreover, alpha-LpA-I/A-II appears to accumulate cholesteryl esters, at least partially, from alpha-LpA-I.
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Affiliation(s)
- Y Huang
- Institut für Arterioskleroseforschung an der Universität Münster, Germany
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5
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Lagrost L, Dengremont C, Athias A, de Geitere C, Fruchart JC, Lallemant C, Gambert P, Castro G. Modulation of cholesterol efflux from Fu5AH hepatoma cells by the apolipoprotein content of high density lipoprotein particles. Particles containing various proportions of apolipoproteins A-I and A-II. J Biol Chem 1995; 270:13004-9. [PMID: 7768892 DOI: 10.1074/jbc.270.22.13004] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The influence of apolipoproteins (apo) A-I and A-II on the ability of high density lipoproteins (HDL) to remove cholesterol from cultured Fu5AH rat hepatoma cells was studied independently on alterations in the overall structure and lipid composition of the lipoprotein particles. To this end, apoA-I was progressively replaced by apoA-II in ultracentrifugally isolated HDL3 without inducing changes in other remaining lipoprotein components. As apoA-II was progressively substituted for apoA-I in HDL3 (A-II:A-I+A-II percentage mass: 29.5, 47.6, 71.5, 97.4, and 98.9%), the rate of cholesterol efflux from Fu5AH hepatoma gradually and significantly decreased after 2 or 4 h of incubation at 37 degrees C (cholesterol efflux: 30.4 +/- 0.8, 24.1 +/- 1.0, 19.8 +/- 1.2, 15.7 +/- 1.4, and 13.4 +/- 1.3%/2h, respectively; 38.4 +/- 1.5, 29.2 +/- 0.9, 27.0 +/- 0.2, 20.4 +/- 0.4, and 17.5 +/- 1.0%/4h, respectively) (p < 0.01 with all A-II-enriched HDL3 fractions as compared with non-enriched homologues). In agreement with data obtained with total HDL3, increasing the A-II:A-I+A-II percentage mass in HDL3 particles containing initially only apoA-I (HDL3-A-I) progressively reduced cellular cholesterol efflux. After 2 h of incubation, cholesterol efflux correlated negatively with A-II:A-I+A-II percentage mass (r = -0.86; p < 0.0001; n = 20), but not with either free cholesterol:phospholipid ratio, A-I+A-II:total lipid ratio or mean size of HDL3. As determined by using Spearman rank correlation analysis, the A-II:A-I+A-II% mass ratio correlated negatively with the apparent maximal efflux (Vmax(efflux)) (rho = -0.68; p < 0.05, n = 10), but not with the HDL3 concentration required to obtain 50% of maximal efflux (Km(efflux)) (rho = -0.08; not significant, n = 10). It was concluded that the apoA-I and apoA-II content of HDL3 is one determinant of its ability to promote cholesterol efflux from Fu5AH rat hepatoma cells.
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Affiliation(s)
- L Lagrost
- Laboratoire de Biochimie des Lipoprotéines, INSERM CJF 93-10, Faculté de Médecine, Dijon, France
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6
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7
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Duverger N, Rader D, Ikewaki K, Nishiwaki M, Sakamoto T, Ishikawa T, Nagano M, Nakamura H, Brewer HB. Characterization of high-density apolipoprotein particles A-I and A-I:A-II isolated from humans with cholesteryl ester transfer protein deficiency. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 227:123-9. [PMID: 7851377 DOI: 10.1111/j.1432-1033.1995.tb20367.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The cholesteryl ester transfer protein (CETP) plays an important role in metabolism of high-density lipoprotein and reverse cholesterol transport in humans. The two major classes of high-density lipoprotein particles are those containing apolipoprotein A-I (LpA-I) and those containing both apoA-I and apoA-II (LpA-I:A-II). We isolated and characterized the apoA-I-containing lipoprotein particles from three subjects with homozygous CETP deficiency (CETP-D) and compared the results with those from normolipidemic control subjects. Plasma concentrations of apoA-I in both LpA-I and LpA-I:A-II were significantly elevated in CETP-D subjects. Both LpA-I and LpA-I:A-II from these subjects were larger and contained more cholesteryl ester per particle than control particles. In CETP-D, subpopulations of LpA-I and LpA-I:A-II with an unusually large size (Stokes diameters 13.8 nm and 12.6 nm, respectively) not detected in normal subjects were isolated. The molar ratio of apoA-I to apoA-II in LpA-I:A-II isolated from CETP-D subjects was higher (mean 2.4) than those of controls (mean 1.4). ApoE was primarily associated with LpA-I:A-II in CETP-D subjects. A subclass of LpA-I with pre-beta migration on agarose electrophoresis was increased in CETP-D subjects. Both LpA-I and LpA-I:A-II from CETP-D subjects bound with higher affinity but less capacity to HepG2 cells compared with control particles, and were internalized to a lesser extent than control particles. These data suggest that the absence of CETP in humans significantly affects the plasma concentration, size, composition, and cellular interaction of both major classes of apoA-I-containing lipoprotein particles.
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Affiliation(s)
- N Duverger
- Molecular Disease Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
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8
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Vallance DT, Byrne DJ, Winder AF. Precipitation procedures used to isolate high density lipoprotein with particular reference to effects on apo A-I-only particles and lipoprotein(a). Clin Chim Acta 1994; 229:77-85. [PMID: 7988057 DOI: 10.1016/0009-8981(94)90230-5] [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: 01/28/2023]
Abstract
Analysis of high density lipoprotein (HDL) isolated from serum without major hypertriglyceridaemia and by five different precipitation methods showed that there were no significant differences in total cholesterol and triglyceride concentrations in the HDL supernatants prepared by the different methods but that free cholesterol, phospholipid, apolipoprotein (apo) A-I and HDL particles containing apo A-I but not apo A-II (LpAI) concentrations were significantly lower for heparin-manganese chloride method 2 (final manganese chloride concentration 92 mmol/l) compared with the other methods. Modest differences in HDL cholesterol, apo A-I and LpAI were observed between heparin-manganese chloride method 1 (final magnesium concentration 46 mmol/l) and the dextran sulphate, phosphotungstate and polyethylene glycol 6000 methods. Lipoprotein(a) (Lp(a)) and apo B were undetectable in the HDL supernatants, indicating that apo B-containing lipoproteins including Lp(a) were essentially completely removed by all the precipitation procedures.
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Affiliation(s)
- D T Vallance
- Department of Chemical Pathology and Human Metabolism, Royal Free Hospital School of Medicine, University of London, UK
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9
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The influence of apolipoproteins on the structure and function of spheroidal, reconstituted high density lipoproteins. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)34060-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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10
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Duverger N, Ghalim N, Theret N, Fruchart JC, Castro G. Lipoproteins containing apolipoprotein A-IV: composition and relation to cholesterol esterification. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1211:23-8. [PMID: 8123678 DOI: 10.1016/0005-2760(94)90134-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In order to investigate the relationship of lipid and apolipoprotein composition to cholesterol esterification in lipoproteins containing apolipoprotein (apo) A-IV, apo A-containing lipoprotein particles were isolated from fresh human plasma using a system of sequential immunoaffinity chromatography. Plasma was first depleted of apo B- and apo E-containing lipoproteins. Four major subpopulations of apo A-containing lipoprotein particles were separated: Lp A-I, Lp A-I: A-II, Lp A-IV and Lp A-I: A-IV: A-II. Lp A-IV and Lp A-I: A-IV: A-II contained less total lipid, less cholesterol and more triacylglycerol than Lp A-I and Lp A-I: A-II. Lp A-IV and Lp A-I: A-IV: A-II contained more sphingomyelin and less phosphatidylcholine than Lp A-I and Lp A-I: A-II and were richer in (16:0 + 18:0) saturated fatty acids. Among these isolated lipoprotein particles, Lp A-IV contained the highest lecithin: cholesterol acyltransferase (LCAT) activity per micrograms of protein. Cholesterol esterification rates were 2.6 +/- 0.5, 5.3 +/- 0.4 and 0.8 +/- 0.2 mumol of cholesterol per hour per mg of lipoproteins for Lp A-IV, Lp A-I and Lp A-I: A-II, respectively. The apolipoprotein and lipid composition and LCAT activity of Lp A-IV suggest that this lipoprotein may be a source of cholesterol esterification in plasma.
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Affiliation(s)
- N Duverger
- Institut Pasteur, INSERM U325, Lille, France
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11
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Lagrost L, Perségol L, Lallemant C, Gambert P. Influence of apolipoprotein composition of high density lipoprotein particles on cholesteryl ester transfer protein activity. Particles containing various proportions of apolipoproteins AI and AII. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)41847-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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12
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Pieters MN, Schouten D, Van Berkel TJ. In vitro and in vivo evidence for the role of HDL in reverse cholesterol transport. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1225:125-34. [PMID: 8280780 DOI: 10.1016/0925-4439(94)90069-8] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- M N Pieters
- Division of Biopharmaceutics, Leiden-Amsterdam Center for Drug Research, Sylvius Laboratories, University of Leiden, The Netherlands
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13
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Duverger N, Rader D, Duchateau P, Fruchart JC, Castro G, Brewer HB. Biochemical characterization of the three major subclasses of lipoprotein A-I preparatively isolated from human plasma. Biochemistry 1993; 32:12372-9. [PMID: 8241125 DOI: 10.1021/bi00097a014] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Apolipoprotein (apo) A-I is the major protein constituent of plasma high-density lipoproteins (HDL). HDL consist of two major classes of apoA-I-containing lipoproteins: LpA-I and LpA-I:A-II. LpA-I includes heterogeneous lipoprotein particles that differ in size and hydrated density. LpA-I was isolated by immunoaffinity chromatography from the fasting plasma of 24 normal human subjects and separated by gel filtration chromatography. Three major subclasses of LpA-I were eluted: large (Lg-LpA-I), medium (Md-LpA-I), and small LpA-I (Sm-LpA-I). By nondenaturing gradient PAGE, Lg-LpA-I, Md-LpA-I, and Sm-LpA-I had mean Strokes diameters of 10.8 +/- 0.5, 8.9 +/- 0.5, and 7.5 +/- 0.3 nm, respectively. The lipid/protein ratios were 1.25 +/- 0.12 for Lg-LpA-I, 0.75 +/- 0.10 for Md-LpA-I, and 0.38 +/- 0.08 for Sm-LpA-I. Lg-LpA-I was relatively lipid and cholesteryl ester rich compared with Md-LpA-I and Sm-LpA-I. Sm-LpA-I contained phospholipids as the major lipid component. ApoA-I was the major apolipoprotein in all LpA-I subfractions, whereas apoE was present only in Lg-LpA-I and apoA-IV was associated with both Md-LpA-I and Sm-LpA-I. All three LpA-I subclasses exhibited predominantly alpha mobility on agarose electrophoresis. Lg-LpA-I migrated as a diffuse band in the fast alpha position, whereas Md-LpA-I and Sm-LpA-I migrated to the slow alpha position.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- N Duverger
- Molecular Disease Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
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14
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Sattler W, Stocker R. Greater selective uptake by Hep G2 cells of high-density lipoprotein cholesteryl ester hydroperoxides than of unoxidized cholesteryl esters. Biochem J 1993; 294 ( Pt 3):771-8. [PMID: 8379932 PMCID: PMC1134528 DOI: 10.1042/bj2940771] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have observed recently that high-density lipoproteins (HDL) are the predominant carriers of cholesteryl ester hydroperoxides (CEOOH), the major class of lipid hydroperoxides detectable at nanomolar concentrations in the plasma of healthy fasting humans. The present study investigates the effect of such very low levels of CEOOH in apolipoprotein E-free HDL3 on lipoprotein particle metabolism and 'selective uptake' of its CE by human Hep G2 cells. Minimal oxidation with aqueous peroxyl radicals had a negligible effect on the binding, internalization and degradation of 125I-labelled HDL3. In contrast, with an increasing degree of radical-mediated oxidation of labelled HDL3, [3H]cholesteryl linoleate ([3H]Ch18:2) was taken up at an increasingly greater rate than were 125I-apoproteins. When [3H]cholesteryl linoleate hydroperoxide ([3H]Ch18:2-OOH was incorporated into unoxidized HDL3 by exchange from donor liposomes, it was taken up at a more than 8-fold higher rate than was incorporated [3H]Ch18:2. The same degree of preferential uptake of oxidized CE was observed when HDL3 was used that was doubly labelled with [3H]Ch18:2-OOH and cholesteryl [14C]oleate ([14C]Ch18:1). In both situations, uptake of [3H]Ch18:2-OOH exceeded that of 125I-apolipoprotein A-I some 40-fold. This increased selective uptake of [3H]Ch18:2-OOH from very mildly oxidized HDL3 was accompanied by a parallel increase in the intracellular levels of labelled free cholesterol. In contrast, lipid hydroperoxides were not detectable within Hep G2 cells, suggesting efficient detoxification of CEOOH by these cells. Neither the increased selective uptake of Ch18:2-OOHs nor the levels of intracellular free cholesterol were influenced by the presence of 50 microM chloroquine, suggesting extralysosomal hydrolysis of oxidized CEs. These results show that the selective uptake of HDL CEOOH by Hep G2 cells is more efficient than that of unoxidized CE, and support a protective role for rapid selective uptake in the removal of circulating HDL CEOOH.
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Affiliation(s)
- W Sattler
- Biochemistry Group, Heart Research Institute, Campertown, N.S.W., Australia
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15
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Duchateau P, Rader D, Duverger N, Theret N, De Geitere C, Brewer HB, Fruchart JC, Castro GR. Tangier disease: isolation and characterization of LpA-I, LpA-II, LpA-I: A-II and LpA-IV particles from plasma. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1182:30-6. [PMID: 8347683 DOI: 10.1016/0925-4439(93)90149-u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Tangier disease (TD) is characterized by extremely low plasma levels of HDL, apoA-I and apoA-II due to very rapid catabolism. However, the risk of premature coronary heart disease (CHD) is not markedly increased in TD. In order to gain insight into reverse cholesterol transport in TD, we isolated LpA-I, LpA-I:A-II, LpA-II and LpA-IV particles from fasting plasma of 5 TD patients. LpA-I composition was similar to control LpA-I, but TD LpA-I had more LCAT and CETP activity (respectively, 0.35 +/- 0.14 and 0.14 +/- 0.04 mumol of cholesterol esterified/h/micrograms of protein, and 7 +/- 2.5 and 1.4 +/- 0.3 mumol of cholesteryl ester transferred/h/micrograms of protein). In contrast, TD LpA-I:A-II had abnormal composition, with a low molar ratio of apoA-I to apoA-II (0.2-1.33). In addition, LpA-I:A-II in TD contained a substantial amount of apoA-IV compared with control, making this particle an LpA-I:A-II:A-IV complex. LpA-I:A-II from normal plasma do not promote cholesterol efflux from adipocytes cells, whereas TD LpA-I:A-II:A-IV complexes promoted cholesterol efflux from these cells. Moreover LpA-I:A-II:A-IV complexes have more LCAT and CETP activity than control (respectively 1.2 +/- 0.16 and 0.05 +/- 0.01 mumol of cholesterol esterified/h/micrograms of protein and, 41 +/- 3.7 and 1 +/- 0.4 mumol of cholesteryl ester transferred/h/micrograms of protein). The LpA-II particle in TD represented in fact an LpA-II:A-IV complex (75% mol apoA-II and 22% mol apoA-IV).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P Duchateau
- Institut Pasteur, INSERM U. 325, Lille, France
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16
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Naohiko S, Shizuya Y, Yuhya U, Toshiharu K, Tadashi N, Tohru F, Kaoru KT, Sumio K, Masaharu K, Katsuto T, Seiichiro T, Yuji M. Extralysosomal degradation of high-density lipoproteins in a human hepatoma cell line, Mahlavu. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0005-2760(93)90202-k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Pieters MN, Castro GR, Schouten D, Duchateau P, Fruchart JC, Van Berkel TJ. Cholesterol esters selectively delivered in vivo by high-density-lipoprotein subclass LpA-I to rat liver are processed faster into bile acids than are LpA-I/A-II-derived cholesterol esters. Biochem J 1993; 292 ( Pt 3):819-23. [PMID: 8318010 PMCID: PMC1134187 DOI: 10.1042/bj2920819] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
High-density lipoprotein (HDL) subclass LpA-I has been reported to promote cholesterol efflux from mouse adipose cells in vitro, whereas subclass LpA-I/A-II has no effect. To investigate whether the apolipoprotein composition of HDL plays a role in the selective delivery of cholesterol esters to the liver in vivo, we labelled HDL in its cholesterol ester moiety and separated [3H]cholesterol oleate-labelled HDL into subclasses LpA-I and LpA-I/A-II by immuno-affinity chromatography. Serum decay and liver association of LpA-I and LpA-I/A-II were compared for the apoprotein and cholesterol ester moieties. Both LpA-I and LpA-I/A-II selectively delivered cholesterol esters to the liver with similar kinetics. The kinetics of biliary secretion of processed cholesterol esters, initially associated with LpA-I or LpA-I/A-II, were studied in rats equipped with permanent catheters in bile, duodenum and heart. For both LpA-I and LpA-I/A-II, liver association was coupled to bile acid synthesis, with an increase in secretion rate during the night. During the first night period, the biliary secretion of LpA-I-derived radio-activity was significantly greater than for LpA-I/A-II. The data indicate that with both LpA-I and LpA-I/A-II selective delivery of cholesterol esters from HDL to the liver occurs, but that cholesterol esters delivered by LpA-I are more efficiently coupled to bile acid synthesis.
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Affiliation(s)
- M N Pieters
- Division of Biopharmaceutics, Sylvius Laboratory, University of Leiden, The Netherlands
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18
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Abstract
High-density lipoprotein (HDL) consists of a heterogeneous group of particles defined either by size or by apolipoprotein content. Subfractions of HDL appear to have distinct but interrelated metabolic functions, including facilitation of cholesteryl ester transfer to low- and very-low-density lipoproteins, modulation of triglyceride-rich particle catabolism, and, possibly, removal of cholesterol from peripheral tissues. Like HDL cholesterol, HDL subfractions are widely affected by a variety of factors. Subfractions also are markers for epidemiologic risk for coronary artery disease. Because they provide information about the physiologic processes of cholesterol metabolism, HDL subfractions are emerging as an increasingly important tool in the study of the relationship between lipids and cardiovascular disease.
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Affiliation(s)
- D I Silverman
- University of Connecticut Health Center, Farmington 06030
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19
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Rye KA, Garrety KH, Barter PJ. Preparation and characterization of spheroidal, reconstituted high-density lipoproteins with apolipoprotein A-I only or with apolipoprotein A-I and A-II. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1167:316-25. [PMID: 8481394 DOI: 10.1016/0005-2760(93)90235-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study describes the preparation of spheroidal reconstituted HDL which contain apolipoprotein (apo) A-I only, (A-I w/o A-II) r-HDL, or apo A-I and apo A-II, (A-I w A-II) r-HDL. Spheroidal (A-I w/o A-II) r-HDL with diameters of 8.0, 9.2 and 11.2 nm were prepared by incubating discoidal (A-I w/o A-II) r-HDL with lecithin-cholesterol acyltransferase and low-density lipoproteins. Spheroidal (A-I w A-II) r-HDL were prepared by displacing apo A-I from spheroidal (A-I w/o A-II) r-HDL with apo A-II. Modification with apo A-II did not significantly affect the diameters of the 8.0 and 9.2 nm (A-I w/o A-II) r-HDL. When, however, apo A-II was added to the (A-I w/o A-II) r-HDL of diameter 11.2 nm, the size of the particles decreased to 9.4 nm. To determine whether modification of (A-I w/o A-II) r-HDL with apo A-II altered the structure of the r-HDL, the packing of phospholipids in the modified and unmodified particles was compared by steady state fluorescence polarization and the environments of the apo A-I tryptophan residues in (A-I w/o A-II) and (A-I w A-II) r-HDL were compared by fluorescence spectroscopy. The results of these studies suggested that modification of spheroidal (A-I w/o A-II) r-HDL with apo A-II alters the environment of apo A-I tryptophan residues in small, but not large, r-HDL and does not affect the packing of phospholipids.
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Affiliation(s)
- K A Rye
- Graduate School of Health and Medical Sciences, University of Wollongong, Australia
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20
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Leroy A, Toohill K, Fruchart J, Jonas A. Structural properties of high density lipoprotein subclasses homogeneous in protein composition and size. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53467-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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21
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Zannis VI, Kardassis D, Zanni EE. Genetic mutations affecting human lipoproteins, their receptors, and their enzymes. ADVANCES IN HUMAN GENETICS 1993; 21:145-319. [PMID: 8391199 DOI: 10.1007/978-1-4615-3010-7_3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- V I Zannis
- Department of Medicine, Housman Medical Research Center, Boston University Medical Center, Massachusetts 02118
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22
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Hagiage M, Marti C, Rigaud D, Senault C, Fumeron F, Apfelbaum M, Girard-Globa A. Effect of a moderate alcohol intake on the lipoproteins of normotriglyceridemic obese subjects compared with normoponderal controls. Metabolism 1992; 41:856-61. [PMID: 1640863 DOI: 10.1016/0026-0495(92)90167-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Moderate alcohol intake is frequently associated with an elevated concentration of high-density lipoprotein (HDL), which is one of the potential causes for the relative decrease in cardiovascular risk reported in moderate drinkers. Conversely, low HDL concentrations, particularly HDL2, in obese subjects may be a risk factor. The effect of 30 g alcohol daily (wine) during 14 days following a period of abstinence was studied in seven normolipidemic obese subjects (body mass index [BMI], 30 +/- 1.7 kg/m2) compared with seven normoponderal controls (BMI, 22 +/- 1.2 kg/m2). Alcohol caused apolipoprotein (apo) AI and apo AII concentrations to increase in all controls by 12% and 16% (P less than .05), but not in obese subjects. Lipoprotein (Lp) AI HDL particles (without AII) were initially in the same proportions in the two groups. Their increase in controls only (P less than .03) was not matched by an increase in HDL2 in all subjects. In obese subjects, neither Lp AI nor HDL2 were increased by alcohol, but their HDL-triglyceride (TG) contents, initially elevated, were normalized. Cholesterol ester (CE) transfer activity was not different in controls and obese subjects during abstinence (105.7 +/- 40.8 v 104.8 +/- 34.5 mmol/mg protein/h). It was notably depressed by alcohol in controls (74.2 +/- 27.4, P less than .002), but not in obese subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Hagiage
- INSERM U-286, Faculté Xavier Bichat, Paris, France
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23
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Vadiveloo PK, Fidge NH. The role of apoproteins AI and AII in binding of high-density lipoprotein3 to membranes derived from bovine aortic endothelial cells. Biochem J 1992; 284 ( Pt 1):145-51. [PMID: 1599393 PMCID: PMC1132709 DOI: 10.1042/bj2840145] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Although binding of high-density lipoproteins (HDL) to a variety of cells in culture has been widely reported, the mechanism of this binding has yet to be fully elucidated. The aim of the current studies was to explore the roles of apoproteins (apo) AI and AII in HDL3 binding to membranes derived from bovine aortic endothelial cells. Binding studies showed that HDL3 (which contains both apo AI and apo AII) and AII-HDL3 (which contain only apo AII) bound to membranes with similar affinity (44 +/- 6 and 41 +/- 9 micrograms/ml respectively) and capacity (673 +/- 97 and 969 +/- 101 ng bound/mg of membrane protein respectively). In contrast with these results, HDL3 [AI w/o AII] (which contain apo AI, but not apo AII) bound to the membranes with a significantly higher capacity (2228 +/- 206 ng bound/mg of membrane protein) and lower affinity (65 +/- 3 micrograms/ml) as compared with HDL3 or AII-HDL3. Therefore, although both apo AI and apo AII appear capable of facilitating HDL3 binding, the mechanisms involved probably differ. A model which fits the data postulates that a common receptor exists which binds both apo AI and apo AII, and that a particle containing AII can occupy up to four receptors (partly owing to each AII molecule containing two binding domains), whereas an HDL3 [AI w/o AII] particle can occupy only one.
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Affiliation(s)
- P K Vadiveloo
- Baker Medical Research Institute, Prahran, Victoria, Australia
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24
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Kraft HG, Demosky SJ, Schumacher K, Brewer HB, Hoeg JM. Regulation of LDL receptor, apoB, and apoE protein and mRNA in Hep G2 cells. DNA Cell Biol 1992; 11:291-300. [PMID: 1605852 DOI: 10.1089/dna.1992.11.291] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The regulation of low-density lipoprotein (LDL) receptor activity, protein synthesis, and cellular mRNA content was evaluated in the human hepatoma cell line Hep G2. Incubation of the cells with LDL led to a complete downregulation of LDL receptor mRNA and LDL receptor protein synthesis. This LDL regulation of the LDL receptor and its mRNA was both time- and concentration-dependent. In contrast to protein synthesis and cellular mRNA concentrations of the LDL receptor, which were reduced to undetectable levels by prolonged incubation in the presence of LDL, LDL receptor activity was reduced to only 44% of preincubation levels. These findings support the presence of a second metabolic pathway for LDL uptake in human hepatocytic cells. The effect of LDL on cellular LDL receptor expression was specific for LDL because incubation in the presence of HDL did not affect any of these study end points. The potential coordinate regulation of the expression of the LDL receptor with its principal ligands, apolipoproteins (apo) B and E, was also investigated. In contrast to the LDL receptor mRNA downregulation with LDL incubation, cellular apoB and apoE mRNA concentrations were not affected by either LDL or HDL. Secretion of apoB, however, was significantly increased by incubating Hep G2 cells with LDL. These findings indicate that, in contrast to LDL receptor which is regulated at the mRNA level, the ligands for the LDL receptor are regulated either co- or post-translationally.
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Affiliation(s)
- H G Kraft
- Molecular Disease Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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25
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Cardot P, Chambaz J, Cladaras C, Zannis V. Regulation of the human ApoA-II gene by the synergistic action of factors binding to the proximal and distal regulatory elements. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54251-4] [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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26
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Cholesterol efflux from cells to immunopurified subfractions of human high density lipoprotein: LP-AI and LP-AI/AII. J Lipid Res 1991. [DOI: 10.1016/s0022-2275(20)41902-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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27
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Rader DJ, Castro G, Zech LA, Fruchart JC, Brewer HB. In vivo metabolism of apolipoprotein A-I on high density lipoprotein particles LpA-I and LpA-I,A-II. J Lipid Res 1991. [DOI: 10.1016/s0022-2275(20)41639-6] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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28
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Johnson WJ, Mahlberg FH, Rothblat GH, Phillips MC. Cholesterol transport between cells and high-density lipoproteins. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1085:273-98. [PMID: 1911862 DOI: 10.1016/0005-2760(91)90132-2] [Citation(s) in RCA: 379] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Various types of studies in humans and animals suggest strongly that HDL is anti-atherogenic. The anti-atherogenic potential of HDL is thought to be due to its participation in reverse cholesterol transport, the process by which cholesterol is removed from non-hepatic cells and transported to the liver for elimination from the body. Extensive studies in cell culture systems have demonstrated that HDL is an important mediator of sterol transport between cells and the plasma compartment. The topic of this review is the mechanisms that account for sterol movement between HDL and cells. The most prominent and easily measured aspect of sterol movement between HDL and cells is the rapid bidirectional transfer of cholesterol between the lipoprotein and the plasma membrane. This movement occurs by unmediated diffusion, and in most situations its rate in each direction is limited by the rate of desorption of sterol molecules from the donor surface into the adjacent water phase. The net transfer of sterol mass out of cells occurs when there is either a relative enrichment of sterol within the plasma membrane or a depletion of sterol in HDL. Recent studies suggest that certain minor subfractions of HDL (with pre-beta mobility on agarose gel electrophoresis and containing apoprotein A-I but no apo A-II) are unusually efficient at promoting efflux of cell sterol. To what extent efflux to these HDL fractions is balanced by influx from the lipoprotein has not yet been established clearly. The prevention and reversal of atherosclerosis require the mobilization of cholesterol from internal (non-plasma membrane) cellular locations. To some extent, this may involve the retroendocytosis of HDL. However, most mobilization probably involves the transport of internal sterol to the plasma membrane, followed by desorption to extracellular HDL. Several laboratories are investigating the transport of sterol from intracellular locations to the plasma membrane. Studies on biosynthetic sterol (probably originating mostly in the smooth endoplasmic reticulum) suggest that there is rapid transport to the plasma membrane in lipid-rich vesicles. Important features of this transport are that it bypasses the Golgi apparatus and may be positively regulated by the specific binding of HDL to the plasma membrane.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- W J Johnson
- Department of Physiology and Biochemistry, Medical College of Pennsylvania, Philadelphia 19129
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29
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Mahlberg F, Glick J, Lund-Katz S, Rothblat G. Influence of apolipoproteins AI, AII, and Cs on the metabolism of membrane and lysosomal cholesterol in macrophages. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54872-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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