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Ossoli A, Simonelli S, Varrenti M, Morici N, Oliva F, Stucchi M, Gomaraschi M, Strazzella A, Arnaboldi L, Thomas MJ, Sorci-Thomas MG, Corsini A, Veglia F, Franceschini G, Karathanasis SK, Calabresi L. Recombinant LCAT (Lecithin:Cholesterol Acyltransferase) Rescues Defective HDL (High-Density Lipoprotein)-Mediated Endothelial Protection in Acute Coronary Syndrome. Arterioscler Thromb Vasc Biol 2020; 39:915-924. [PMID: 30894011 DOI: 10.1161/atvbaha.118.311987] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Objective- Aim of this study was to evaluate changes in LCAT (lecithin:cholesterol acyltransferase) concentration and activity in patients with an acute coronary syndrome, to investigate if these changes are related to the compromised capacity of HDL (high-density lipoprotein) to promote endothelial nitric oxide (NO) production, and to assess if rhLCAT (recombinant human LCAT) can rescue the defective vasoprotective HDL function. Approach and Results- Thirty ST-segment-elevation myocardial infarction (STEMI) patients were enrolled, and plasma was collected at hospital admission, 48 and 72 hours thereafter, at hospital discharge, and at 30-day follow-up. Plasma LCAT concentration and activity were measured and related to the capacity of HDL to promote NO production in cultured endothelial cells. In vitro studies were performed in which STEMI patients' plasma was added with rhLCAT and HDL vasoprotective activity assessed by measuring NO production in endothelial cells. The plasma concentration of the LCAT enzyme significantly decreases during STEMI with a parallel significant reduction in LCAT activity. HDL isolated from STEMI patients progressively lose the capacity to promote NO production by endothelial cells, and the reduction is related to decreased LCAT concentration. In vitro incubation of STEMI patients' plasma with rhLCAT restores HDL ability to promote endothelial NO production, possibly related to significant modification in HDL phospholipid classes. Conclusions- Impairment of cholesterol esterification may be a major factor in the HDL dysfunction observed during acute coronary syndrome. rhLCAT is able to restore HDL-mediated NO production in vitro, suggesting LCAT as potential therapeutic target for restoring HDL functionality in acute coronary syndrome.
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Affiliation(s)
- Alice Ossoli
- From the Centro E. Grossi Paoletti (A.O., S.S., M.G., A.S., G.F., L.C.), Università degli Studi di Milano, Italy
| | - Sara Simonelli
- From the Centro E. Grossi Paoletti (A.O., S.S., M.G., A.S., G.F., L.C.), Università degli Studi di Milano, Italy
| | - Marisa Varrenti
- Cardiologia 1-Emodinamica, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy (M.V., N.M., F.O., M.S.).,Università degli Studi di Milano-Bicocca, Italy (M.V.)
| | - Nuccia Morici
- Department of Clinical Sciences and Community Health (N.M.), Università degli Studi di Milano, Italy.,Cardiologia 1-Emodinamica, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy (M.V., N.M., F.O., M.S.)
| | - Fabrizio Oliva
- Cardiologia 1-Emodinamica, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy (M.V., N.M., F.O., M.S.)
| | - Miriam Stucchi
- Cardiologia 1-Emodinamica, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy (M.V., N.M., F.O., M.S.)
| | - Monica Gomaraschi
- From the Centro E. Grossi Paoletti (A.O., S.S., M.G., A.S., G.F., L.C.), Università degli Studi di Milano, Italy
| | - Arianna Strazzella
- From the Centro E. Grossi Paoletti (A.O., S.S., M.G., A.S., G.F., L.C.), Università degli Studi di Milano, Italy
| | - Lorenzo Arnaboldi
- Dipartimento di Scienze Farmacologiche e Biomolecolari (L.A., A.C.), Università degli Studi di Milano, Italy
| | - Michael J Thomas
- Department of Pharmacology and Toxicology (M.J.T.), Medical College of Wisconsin, Milwaukee
| | - Mary G Sorci-Thomas
- Division of Endocrinology, Metabolism and Clinical Nutrition, Department of Medicine (M.G.S.-T.), Medical College of Wisconsin, Milwaukee
| | - Alberto Corsini
- Dipartimento di Scienze Farmacologiche e Biomolecolari (L.A., A.C.), Università degli Studi di Milano, Italy
| | | | - Guido Franceschini
- From the Centro E. Grossi Paoletti (A.O., S.S., M.G., A.S., G.F., L.C.), Università degli Studi di Milano, Italy
| | | | - Laura Calabresi
- From the Centro E. Grossi Paoletti (A.O., S.S., M.G., A.S., G.F., L.C.), Università degli Studi di Milano, Italy
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Dal Magro R, Simonelli S, Cox A, Formicola B, Corti R, Cassina V, Nardo L, Mantegazza F, Salerno D, Grasso G, Deriu MA, Danani A, Calabresi L, Re F. The Extent of Human Apolipoprotein A-I Lipidation Strongly Affects the β-Amyloid Efflux Across the Blood-Brain Barrier in vitro. Front Neurosci 2019; 13:419. [PMID: 31156358 PMCID: PMC6532439 DOI: 10.3389/fnins.2019.00419] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/11/2019] [Indexed: 12/20/2022] Open
Abstract
Much evidence suggests a protective role of high-density lipoprotein (HDL) and its major apolipoprotein apoA-I, in Alzheimer’s disease (AD). The biogenesis of nascent HDL derived from a first lipidation of apoA-I, which is synthesized by the liver and intestine but not in the brain, in a process mediated by ABCA1. The maturation of nascent HDL in mature spherical HDL is due to a subsequent lipidation step, LCAT-mediated cholesterol esterification, and the change of apoA-I conformation. Therefore, different subclasses of apoA-I-HDL simultaneously exist in the blood circulation. Here, we investigated if and how the lipidation state affects the ability of apoA-I-HDL to target and modulate the cerebral β-amyloid (Aβ) content from the periphery, that is thus far unclear. In particular, different subclasses of HDL, each with different apoA-I lipidation state, were purified from human plasma and their ability to cross the blood-brain barrier (BBB), to interact with Aβ aggregates, and to affect Aβ efflux across the BBB was assessed in vitro using a transwell system. The results showed that discoidal HDL displayed a superior capability to promote Aβ efflux in vitro (9 × 10-5 cm/min), when compared to apoA-I in other lipidation states. In particular, no effect on Aβ efflux was detected when apoA-I was in mature spherical HDL, suggesting that apoA-I conformation, and lipidation could play a role in Aβ clearance from the brain. Finally, when apoA-I folded its structure in discoidal HDL, rather than in spherical ones, it was able to cross the BBB in vitro and strongly destabilize the conformation of Aβ fibrils by decreasing the order of the fibril structure (-24%) and the β-sheet content (-14%). These data suggest that the extent of apoA-I lipidation, and consequently its conformation, may represent crucial features that could exert their protective role in AD pathogenesis.
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Affiliation(s)
- Roberta Dal Magro
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Sara Simonelli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro Grossi Paoletti, Università degli Studi di Milano, Milan, Italy
| | - Alysia Cox
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Beatrice Formicola
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Roberta Corti
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Valeria Cassina
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Luca Nardo
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Francesco Mantegazza
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Domenico Salerno
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Gianvito Grasso
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale, Scuola Universitaria Professionale della Svizzera Italiana, Università della Svizzera Italiana, Manno, Switzerland
| | - Marco Agostino Deriu
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale, Scuola Universitaria Professionale della Svizzera Italiana, Università della Svizzera Italiana, Manno, Switzerland
| | - Andrea Danani
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale, Scuola Universitaria Professionale della Svizzera Italiana, Università della Svizzera Italiana, Manno, Switzerland
| | - Laura Calabresi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro Grossi Paoletti, Università degli Studi di Milano, Milan, Italy
| | - Francesca Re
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
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Gomaraschi M, Ossoli A, Castelnuovo S, Simonelli S, Pavanello C, Balzarotti G, Arca M, Di Costanzo A, Sampietro T, Vaudo G, Baldassarre D, Veglia F, Franceschini G, Calabresi L. Depletion in LpA-I:A-II particles enhances HDL-mediated endothelial protection in familial LCAT deficiency. J Lipid Res 2017; 58:994-1001. [PMID: 28351888 DOI: 10.1194/jlr.p072371] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 03/04/2017] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to evaluate the vasoprotective effects of HDL isolated from carriers of LCAT deficiency, which are characterized by a selective depletion of LpA-I:A-II particles and predominance of preβ migrating HDL. HDLs were isolated from LCAT-deficient carriers and tested in vitro for their capacity to promote NO production and to inhibit vascular cell adhesion molecule-1 (VCAM-1) expression in cultured endothelial cells. HDLs from carriers were more effective than control HDLs in promoting eNOS activation with a gene-dose-dependent effect (PTrend = 0.048). As a consequence, NO production induced by HDL from carriers was significantly higher than that promoted by control HDL (1.63 ± 0.24-fold vs. 1.34 ± 0.07-fold, P = 0.031). HDLs from carriers were also more effective than control HDLs in inhibiting the expression of VCAM-1 (homozygotes, 65.0 ± 8.6%; heterozygotes, 53.1 ± 7.2%; controls, 44.4 ± 4.1%; PTrend = 0.0003). The increased efficiency of carrier HDL was likely due to the depletion in LpA-I:A-II particles. The in vitro findings might explain why carriers of LCAT deficiency showed flow-mediated vasodilation and plasma-soluble cell adhesion molecule concentrations comparable to controls, despite low HDL-cholesterol levels. These results indicate that selective depletion of apoA-II-containing HDL, as observed in carriers of LCAT deficiency, leads to an increased capacity of HDL to stimulate endothelial NO production, suggesting that changes in HDL apolipoprotein composition may be the target of therapeutic interventions designed to improve HDL functionality.
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Affiliation(s)
- Monica Gomaraschi
- Centro E. Grossi Paoletti, Dipartimento di Scienze Farmacologiche e Biomolecolari Università degli Studi di Milano, Milano, Italy
| | - Alice Ossoli
- Centro E. Grossi Paoletti, Dipartimento di Scienze Farmacologiche e Biomolecolari Università degli Studi di Milano, Milano, Italy
| | - Samuela Castelnuovo
- Centro Dislipidemie, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Sara Simonelli
- Centro E. Grossi Paoletti, Dipartimento di Scienze Farmacologiche e Biomolecolari Università degli Studi di Milano, Milano, Italy
| | - Chiara Pavanello
- Centro E. Grossi Paoletti, Dipartimento di Scienze Farmacologiche e Biomolecolari Università degli Studi di Milano, Milano, Italy
| | - Gloria Balzarotti
- Centro E. Grossi Paoletti, Dipartimento di Scienze Farmacologiche e Biomolecolari Università degli Studi di Milano, Milano, Italy
| | - Marcello Arca
- Atherosclerosis Center, Department of Internal Medicine and Allied Sciences, Sapienza University of Rome, Rome, Italy
| | - Alessia Di Costanzo
- Atherosclerosis Center, Department of Internal Medicine and Allied Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Gaetano Vaudo
- Department of Medicine, University of Perugia, Perugia, Italy
| | | | | | - Guido Franceschini
- Section of Chemical and Biomolecular Sciences, DeFENS, Università degli Studi di Milano, Milano, Italy
| | - Laura Calabresi
- Centro E. Grossi Paoletti, Dipartimento di Scienze Farmacologiche e Biomolecolari Università degli Studi di Milano, Milano, Italy
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4
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Significance of Determining Levels of Apolipoproteins A-I and B in the Diagnostics and Assessment of Lipid-Related Atherogenic Risk in Hyperalpha-Lipoproteinemia, Hypocholesterolemia and Hypo-Hdl-Cholesterolemia. J Med Biochem 2007. [DOI: 10.2478/v10011-007-0024-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Significance of Determining Levels of Apolipoproteins A-I and B in the Diagnostics and Assessment of Lipid-Related Atherogenic Risk in Hyperalpha-Lipoproteinemia, Hypocholesterolemia and Hypo-Hdl-CholesterolemiaThe significance of determining apolipoproteins apoB and apoA-I and their correlation with lipid status parameters were tested in hyperalpha-lipoproteinemia (30 women), hypocholesterolemia (10 men) and hypo-HDL-cholesterolemia (15 women and 21 men). Control groups were 20 normolipidemic men and women, each. ApoA-I showed positive correlation with HDL-cholesterol in hyperalpha-lipoproteinemia, with total and HDL-cholesterol in hypocholesterolemia, and with total and LDL-cholesterol in females with hypo-HDL-cholesterolemia, and negative correlation with cholesterol ratios only in hypocholesterolemia. ApoB showed a positive correlation with total and LDL-cholesterol in all groups, and with cholesterol ratios in hyperalpha-lipoproteinemia and hypo-HDL-cholesterolemia. The apoB/apoA-I ratio, correlating with the majority of lipid parameters, and with the highest percentage of pathological values in all tested groups, was singled out as the most sensitive parameter for the evaluation of lipid-related atherogenic risks.
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Favari E, Zanotti I, Zimetti F, Ronda N, Bernini F, Rothblat GH. Probucol inhibits ABCA1-mediated cellular lipid efflux. Arterioscler Thromb Vasc Biol 2004; 24:2345-50. [PMID: 15514211 DOI: 10.1161/01.atv.0000148706.15947.8a] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE ATP-binding cassette transporter A1 (ABCA1) mediates the efflux of lipids from cells to lipid-poor apolipoproteins. In this article, we characterize the effect of probucol on cellular ABCA1-mediated lipid efflux. METHODS AND RESULTS Probucol inhibited cholesterol efflux up to 80% in J774 macrophages expressing ABCA1. In Fu5AH hepatoma cells that contain scavenger receptor class B, type I, but not functional ABCA1, we observed no effect of probucol on cholesterol efflux. Probucol inhibited cholesterol efflux from normal human skin fibroblasts but not from fibroblasts from a Tangier patient. Fluorescent confocal microscopy and biotinylation assay demonstrated that in J774 cells probucol impaired the translocation of ABCA1 from intracellular compartments to the plasma membrane. Probucol also inhibited the formation of an ABCA1-linked cholesterol oxidase sensitive plasma membrane domain. Consistent with the inhibitory effect on ABCA1 translocation to the plasma membrane, probucol reduced cell surface-specific [125I]-labeled apolipoprotein-AI binding. CONCLUSIONS We conclude that probucol is an effective inhibitor of ABCA1-mediated cholesterol efflux without influencing scavenger receptor class B type I-mediated efflux. The inhibition of ABCA1 translocation to the plasma membrane may in part explain the reported in vivo high-density lipoprotein-lowering action of probucol.
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Affiliation(s)
- Elda Favari
- Department of Pharmacological and Biological Sciences and Applied Chemistry, University of Parma, Parma, Italy
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6
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Puppione DL, Fischer WH, Park M, Whitelegge JP, Schumaker VN, Golfeiz S, MacDonald MH. Sequence of horse (Equus caballus) apoA-II. Another example of a dimer forming apolipoprotein. Comp Biochem Physiol B Biochem Mol Biol 2004; 138:213-20. [PMID: 15253869 DOI: 10.1016/j.cbpc.2004.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Revised: 02/09/2004] [Accepted: 02/11/2004] [Indexed: 01/07/2023]
Abstract
Apolipoprotein A-II, the second major apolipoprotein of human HDL, also has been observed in a variety of mammals; however, it is either present in trace amounts or absent in other mammals. In humans and chimpanzee, and probably in other great apes, apoA-II with a cysteine at residue 6 is able to form a homodimer. In other primates as well as other mammals, apoA-II, lacking a cysteine residue, is monomeric. However, horse HDL has been reported to contain dimeric apoA-II that following reduction forms monomers. In this report, we extend these observations by reporting on the first complete sequence for a horse apolipoprotein and by demonstrating that horse apoA-II also contains a cysteine residue at position 6. Both the intact protein and its enzymatic fragments were analyzed by chemical sequence analysis and time-of-flight MALDI-MS (matrix assisted laser desorption ionization mass spectrometry). We also obtained molecular mass data on dimeric and monomeric apoA-II using electrospray-ionization mass spectrometry (ESI-MS). The data are compared with other mammalian sequences of apoA-II and are discussed in terms of resulting similarities and variations in the primary sequences.
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Affiliation(s)
- Donald L Puppione
- Boyer Hall, The Molecular Biology Institute and The Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA 90095, USA.
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7
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Favari E, Lee M, Calabresi L, Franceschini G, Zimetti F, Bernini F, Kovanen PT. Depletion of pre-beta-high density lipoprotein by human chymase impairs ATP-binding cassette transporter A1- but not scavenger receptor class B type I-mediated lipid efflux to high density lipoprotein. J Biol Chem 2003; 279:9930-6. [PMID: 14701812 DOI: 10.1074/jbc.m312476200] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ATP-binding cassette transporter A1 (ABCA1) mediates the efflux of cellular unesterified cholesterol and phospholipid to lipid-poor apolipoprotein A-I. Chymase, a protease secreted by mast cells, selectively cleaves pre-beta-migrating particles from high density lipoprotein (HDL)(3) and reduces the efflux of cholesterol from macrophages. To evaluate whether this effect is the result of reduction of ABCA1-dependent or -independent pathways of cholesterol efflux, in this study we examined the efflux of cholesterol to preparations of chymase-treated HDL(3) in two types of cell: 1) in J774 murine macrophages endogenously expressing low levels of scavenger receptor class B, type I (SR-BI), and high levels of ABCA1 upon treatment with cAMP; and 2) in Fu5AH rat hepatoma cells endogenously expressing high levels of the SR-BI and low levels of ABCA1. Treatment of HDL(3) with the human chymase resulted in rapid depletion of pre-beta-HDL and a concomitant decrease in the efflux of cholesterol and phospholipid (2-fold and 3-fold, respectively) from the ABCA1-expressing J774 cells. In contrast, efflux of free cholesterol from Fu5AH to chymase-treated and to untreated HDL(3) was similar. Incubation of HDL(3) with phospholipid transfer protein led to an increase in pre-beta-HDL contents as well as in ABCA1-mediated cholesterol efflux. A decreased cholesterol efflux to untreated HDL(3) but not to chymase-treated HDL(3) was observed in ABCA1-expressing J774 with probucol, an inhibitor of cholesterol efflux to lipid-poor apoA-I. Similar results were obtained using brefeldin and gliburide, two inhibitors of ABCA1-mediated efflux. These results indicate that chymase treatment of HDL(3) specifically impairs the ABCA1-dependent pathway without influencing either aqueous or SR-BI-facilitated diffusion and that this effect is caused by depletion of lipid-poor pre-beta-migrating particles in HDL(3). Our results are compatible with the view that HDL(3) promotes ABCA1-mediated lipid efflux entirely through its lipid-poor fraction with pre-beta mobility.
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Affiliation(s)
- Elda Favari
- Department of Pharmacological and Biological Sciences, and Applied Chemistry, University of Parma, Italy
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Lee M, Kovanen PT, Tedeschi G, Oungre E, Franceschini G, Calabresi L. Apolipoprotein composition and particle size affect HDL degradation by chymase: effect on cellular cholesterol efflux. J Lipid Res 2003; 44:539-46. [PMID: 12562834 DOI: 10.1194/jlr.m200420-jlr200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mast cell chymase, a chymotrypsin-like neutral protease, can proteolyze HDL3. Here we studied the ability of rat and human chymase to proteolyze discoidal pre beta-migrating reconstituted HDL particles (rHDLs) containing either apolipoprotein A-I (apoA-I) or apoA-II. Both chymases cleaved apoA-I in rHDL at identical sites, either at the N-terminus (Tyr18 or Phe33) or at the C-terminus (Phe225), so generating three major truncated polypeptides that remained bound to the rHDL. The cleavage sites were independent of the size of the rHDL particles, but small particles were more susceptible to degradation than bigger ones. Chymase-induced truncation of apoA-I yielded functionally compromised rHDL with reduced ability to promote cellular cholesterol efflux. In sharp contrast to apoA-I, apoA-II was resistant to degradation. However, when apoA-II was present in rHDL that also contained apoA-I, it was degraded by chymase. We conclude that chymase reduces the ability of apoA-I in discoidal rHDL particles to induce cholesterol efflux by cleaving off either its amino- or carboxy-terminal portion. This observation supports the concept that limited extracellular proteolysis of apoA-I is one pathophysiologic mechanism leading to the generation and maintenance of foam cells in atherosclerotic lesions.
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Affiliation(s)
- Miriam Lee
- Wihuri Research Institute, Helsinki, Finland
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9
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Favari E, Bernini F, Tarugi P, Franceschini G, Calabresi L. The C-terminal domain of apolipoprotein A-I is involved in ABCA1-driven phospholipid and cholesterol efflux. Biochem Biophys Res Commun 2002; 299:801-5. [PMID: 12470649 DOI: 10.1016/s0006-291x(02)02745-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ABCA1, a member of the ATP-binding cassette family, mediates the efflux of cellular lipids to free apolipoproteins, mainly apoA-I. The role of the C-terminal domain of apoA-I in this process has been evaluated by measuring the efflux capacity of a truncated form (apoA-I-(1-192)) versus intact apoA-I in different cellular models. In stimulated J774 macrophages, cholesterol efflux to apoA-I-(1-192) was remarkably lower than that to the intact apoA-I. The truncated apoA-I, lacking an important lipid-binding domain, was also significantly less efficient in removing phospholipids from stimulated macrophages. No difference was detected with stimulated Tangier fibroblasts that do not express functional ABCA1. The C-terminal domain of apoA-I is clearly involved in ABCA1-driven lipid efflux. Independent of the interaction with the cell surface, it may be the decreased ability of the truncated apoA-I to recruit membrane phospholipids that impairs its capacity to promote cell cholesterol efflux.
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Affiliation(s)
- Elda Favari
- Department of Pharmacological and Biological Sciences, and Applied Chemistry, University of Parma, Parco Area delle Scienze 27/A, 43100 Parma, Italy
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Lee M, Calabresi L, Chiesa G, Franceschini G, Kovanen PT. Mast cell chymase degrades apoE and apoA-II in apoA-I-knockout mouse plasma and reduces its ability to promote cellular cholesterol efflux. Arterioscler Thromb Vasc Biol 2002; 22:1475-81. [PMID: 12231569 DOI: 10.1161/01.atv.0000029782.84357.68] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Mast cell chymase is a chymotryptic heparin proteoglycan-bound neutral protease that exerts its activity in extracellular fluids. We studied the effect of chymase on the apolipoprotein compositions and the abilities of plasmas from apolipoprotein (apo)A-I-knockout (A-I-KO) and wild-type (C57BL/6J) mice to stimulate efflux of cellular cholesterol from mouse macrophage foam cells. METHODS AND RESULTS The A-I-KO apolipoproteins compared with the wild-type (apoA-I, apoA-II, apoA-IV, and apoE) showed total lack of apoA-I, unaltered apoA-II, an absence of apoA-IV, and an increase of apoE. Despite these major differences, the 2 plasmas induced similar high-affinity efflux of cholesterol from the foam cells. Quantitative analysis of chymase-treated plasmas revealed (1) in A-I-KO plasma, complete loss of apoE and apoA-II, and (2) in wild-type plasma, slight reduction of apoA-I associated with complete depletion of the minor pre-beta-high density lipoprotein fraction, strong reduction of apoA-II, and complete depletion of apoA-IV and apoE. Both proteolyzed plasmas had lost the ability to induce cellular cholesterol efflux with high affinity. Addition of discoidal pre-beta-migrating reconstituted high density lipoprotein particles containing human apoA-I or apoA-II to the chymase-treated A-I-KO plasma fully restored its cholesterol efflux-inducing ability, indicating functional replacement of the proteolyzed apoE and apoA-II. Thus, chymase degraded all the nondeleted apolipoproteins of the A-I-KO plasma involved in the high-affinity efflux of cellular cholesterol. CONCLUSIONS This is the first indication that genetically engineered mice could be used as models for examining the hypothesis that extracellular proteases are involved in the development of atherosclerosis by inhibiting the apolipoprotein-mediated removal of macrophage cholesterol.
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Affiliation(s)
- Miriam Lee
- Wihuri Research Institute, Helsinki, Finland
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Abstract
Apolipoprotein (Apo) A-I and apo A-II are the major apolipoproteins of HDL. It is clearly demonstrated that there are inverse relationships between HDL-cholesterol and apo A-I plasma levels and the risk of coronary heart disease (CHD) in the general population. On the other hand, it is still not clearly demonstrated whether apo A-II plasma levels are associated with CHD risk. A recent prospective epidemiological (PRIME) study suggests that Lp A-I (HDL containing apo A-I but not apo A-II) and Lp A-I:A-II (HDL containing apo A-I and apo A-II) were both reduced in survivors of myocardial infarction, suggesting that both particles are risk markers of CHD. Apo A-II and Lp A-I:A-II plasma levels should be rather related to apo A-II production rate than to apo A-II catabolism. Mice transgenic for both human apo A-I and apo A-II are less protected against atherosclerosis development than mice transgenic for human apo A-I only, but the results of the effects of trangenesis of human apo A-II (in the absence of a co-transgenesis of human apo A-I) are controversial. It is highly suggested that HDL reduce CHD risk by promoting the transfer of peripherical free cholesterol to the liver through the so-called 'reverse cholesterol transfer'. Apo A-II modulates different steps of HDL metabolism and therefore probably alters reverse cholesterol transport. Nevertheless, some effects of apo A-II on intermediate HDL metabolism might improve reverse cholesterol transport and might reduce atherosclerosis development while some other effects might be deleterious. In different in vitro models of cell cultures, Lp A-I:A-II induce either a lower or a similar cellular cholesterol efflux (the first step of reverse cholesterol transport) than Lp A-I. Results depend on numerous factors such as cultured cell types and experimental conditions. Furthermore, the effects of apo A-II on HDL metabolism, beyond cellular cholesterol efflux, are also complex and controversial: apo A-II may inhibit lecithin-cholesterol acyltransferase (LCAT) (potential deleterious effect) and cholesteryl-ester-transfer protein (CETP) (potential beneficial effect) activities, but may increase the hepatic lipase (HL) activity (potential beneficial effect). Apo A-II may also inhibit the hepatic cholesteryl uptake from HDL (potential deleterious effect) probably through the SR-BI depending pathway. Therefore, in terms of atherogenesis, apo A-II alters the intermediate HDL metabolism in opposing ways by increasing (LCAT, SR-BI) or decreasing (HL, CETP) the atherogenicity of lipid metabolism. Effects of apo A-II on atherogenesis are controversial in humans and in transgenic animals and probably depend on the complex effects of apo A-II on these different intermediate metabolic steps which are in weak equilibrium with each other and which can be modified by both endogenous and environmental factors. It can be suggested that apo A-II is not a strong determinant of lipid metabolism, but is rather a modulator of reverse cholesterol transport.
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Affiliation(s)
- Anne Tailleux
- Faculté de Pharmacie, Département d'athérosclérose et INSERM U 545, Institut Pasteur, Université Lille 2, 1, rue du Professeur Calmette, 59019 Cedex, Lille, France.
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Calabresi L, Franceschini G, Sirtori CR, De Palma A, Saresella M, Ferrante P, Taramelli D. Inhibition of VCAM-1 expression in endothelial cells by reconstituted high density lipoproteins. Biochem Biophys Res Commun 1997; 238:61-5. [PMID: 9299452 DOI: 10.1006/bbrc.1997.7236] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Plasma-derived high density lipoproteins (HDL) were found to inhibit cytokine-induced expression of endothelial cell adhesion molecules. Here we used apolipoprotein-specific reconstituted HDL (rHDL) made with phosphatidylcholine (PC) and three different apolipoproteins to identify the HDL components involved in this effect. rHDL containing apolipoprotein A-I (apoA-I), the disulfide-linked form of the apoA-IMilano variant, or apoA-II, were all effective in inhibiting the expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 in TNF alpha- or LPS-stimulated HUVEC. The inhibition was concentration dependent in the range of 0.1-1.0 mg/ml (protein). PC liposomes slightly depressed TNF alpha-induced VCAM-1 expression (16% vs 43-50% for the various rHDL), whereas the lipid-free apolipoproteins had no effect. The protein component of HDL is involved in the inhibition of VCAM-1 expression in HUVEC through a rather unspecific mechanism, as three apolipoproteins with remarkably different primary structure display very similar activity.
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Affiliation(s)
- L Calabresi
- Center E. Grossi Paoletti, Institute of Pharmacological Sciences, Milan, Italy
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Calabresi L, Lucchini A, Vecchio G, Sirtori CR, Franceschini G. Human apolipoprotein A-II inhibits the formation of pre-beta high density lipoproteins. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1304:32-42. [PMID: 8944748 DOI: 10.1016/s0005-2760(96)00102-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The role of human apolipoprotein A-II (apoA-II) in the remodeling of human high density lipoproteins (HDL) was investigated during incubation of native and reduced-carboxamidomethylated (RCM) HDL3 with a lipoprotein-depleted plasma fraction (LPDP) in the presence of triglyceride-rich particles (TGRP) isolated from Intralipid. Reduction-carboxamidomethylation of HDL3 entirely converts the disulfide-linked apoA-II dimers into monomers, without affecting the structure, composition and particle size distribution of HDL3. Following incubation with LPDP and TGRP, unmodified HDL3 are mainly converted into large, HDL2 particles (diameter: 9.90 +/- 0.07 nm), enriched in triglycerides and depleted of cholesteryl esters. RCM-HDL3 are converted into both large HDL2 (9.86 +/- 0.07 nm) and small (7.53 +/- 0.06 nm) HDL3. The small products are protein-rich and cholesterol-poor, and consist of two different particles: a component with pre-beta mobility, containing only apoA-I, and a component with alpha mobility, containing both apoA-I and apoA-II. Kinetic studies suggest that a two-step process is involved in the formation of small, pre beta-HDL3, by which changes in lipid composition cause alterations in lipoprotein structure/stability, favoring the dissociation of apolipoproteins and reduction of particle size. These findings indicate that apolipoprotein structure is a major determinant of HDL remodeling, apoA-II potentially counteracting the anti-atherogenic properties of apoA-I by inhibiting the formation of small, pre-beta-migrating HDL.
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Affiliation(s)
- L Calabresi
- Center E. Grossi Paoletti, Institute of Pharmacological Sciences, University of Milano, Italy
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