1
|
Abstract
The main lifestyle interventions to modify serum HDL cholesterol include physical exercise, weight loss with either caloric restriction or specific dietary approaches, and smoking cessation. Moderate alcohol consumption can be permitted in some cases. However, as these interventions exert multiple effects, it is often difficult to discern which is responsible for improvement in HDL outcomes. It is particularly noteworthy that recent data questions the use of HDL cholesterol as a risk factor and therapeutic target since randomised interventions and Mendelian randomisation studies failed to provide evidence for such an approach. Therefore, these current data should be considered when reading and interpreting this review. Further studies are needed to document the effect of lifestyle changes on HDL structure-function and health.
Collapse
|
2
|
Blatter Garin MC, Moren X, James RW. Paraoxonase-1 and serum concentrations of HDL-cholesterol and apoA-I. J Lipid Res 2006; 47:515-20. [PMID: 16327022 DOI: 10.1194/jlr.m500281-jlr200] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Paraoxonase-1 (PON1) and HDL are tightly associated in plasma, and this is generally assumed to reflect the need for the enzyme to associate with a hydrophobic complex. The association has been examined in coronary cases and age-matched controls. Highly significant (P < 0.0001), positive associations were observed between PON1 activities and concentrations and HDL-cholesterol and apolipoprotein A-I (apoA-I) concentrations in cases and controls. Corrected slopes were significantly different in cases (cases vs. controls: arylesterase, r = 0.19 vs. 0.38, P < 0.02 for apoA-I and r = 0.15 vs. 0.34, P < 0.02 for HDL-cholesterol) such that if PON1 should influence serum HDL, it would be less effective in coronary cases. When examined as a function of the PON1 gene promoter polymorphism C-107 T, highly significant differences (P < 0.001) in HDL-cholesterol and apoA-I were observed between genotypes for controls, with high expresser alleles having the highest HDL concentrations. This relationship was lost in cases with coronary disease. The coding region polymorphisms Q192R and L55M of the PON1 gene showed no association with HDL. The promoter polymorphism was an independent determinant of HDL concentrations in multivariate analyses. These data are consistent with an impact of PON1 on plasma concentrations of HDL, with detrimental modifications to the relationship in coronary cases.
Collapse
Affiliation(s)
- Marie-Claude Blatter Garin
- Clinical Diabetes Unit, Division of Endocrinology, Diabetes, and Nutrition, Medical Faculty, University Hospital, 1211 Geneva 14, Switzerland
| | | | | |
Collapse
|
3
|
Matsunaga T, Koyama I, Hokari S, Komoda T. Detection of oxidized high-density lipoprotein. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 781:331-43. [PMID: 12450667 DOI: 10.1016/s1570-0232(02)00556-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This paper reviews working procedures for the separation and detection of oxidized high-density lipoproteins (ox-HDL) and their constituents. It begins with an introductory overview of structural alterations of the HDL particle and its constituents generated during oxidation. The main body of the review delineates various procedures for the isolation and detection of ox-HDL as well as the purification and separation of phosphatidylcholine metabolites and denatured apolipoproteins in the particle. The useful methods published more recently are picked up and the utility of the separation techniques is described. The last section covers a clinical evaluation of changes in these factors in ox-HDL as well as future directions of ox-HDL research.
Collapse
Affiliation(s)
- Toshiyuki Matsunaga
- Department of Biochemistry, Saitama Medical School, 38 Morohongo, Moroyama, Iruma-gun, Saitama, 350-0495, Japan.
| | | | | | | |
Collapse
|
4
|
Garner B, Witting PK, Waldeck AR, Christison JK, Raftery M, Stocker R. Oxidation of high density lipoproteins. I. Formation of methionine sulfoxide in apolipoproteins AI and AII is an early event that accompanies lipid peroxidation and can be enhanced by alpha-tocopherol. J Biol Chem 1998; 273:6080-7. [PMID: 9497325 DOI: 10.1074/jbc.273.11.6080] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The lipids of high density lipoproteins (HDL) are initially oxidized in preference to those in low density lipoprotein when human plasma is exposed to aqueous peroxyl radicals. In this work we report on the relative susceptibility of HDL protein and lipid to oxidation and on the role HDL's alpha-tocopherol (alpha-TOH) plays in modulating protein oxidation. Exposure of isolated HDL to either low fluxes of aqueous peroxyl radicals, Cu2+ ions, or soybean lipoxygenase resulted in the oxidation of apoAI and apoAII during the earliest stages of the reaction, i.e. after consumption of ubiquinol-10 and in the presence of alpha-TOH. Hydro(pero)xides of cholesteryl esters and phospholipids initially accumulated together with specific oxidized forms of apoAI and apoAII, separated by high pressure liquid chromatography. The specific oxidized forms of apoAI were 16 and 32 mass units heavier than those of the native apolipoproteins and contained 1 and 2 methionine sulfoxide residues per protein, respectively. The third methionine residue in apoAI, as well as Trp residues, remained unoxidized during the earliest stages of HDL oxidation examined. Exposure of isolated apoAI to peroxyl radicals, Cu2+, or soybean lipoxygenase resulted in nonspecific (for peroxyl radicals) or no discernible protein oxidation (Cu2+ and soybean lipoxygenase). This indicated that the formation of the specific oxidized forms of apoAI observed with native HDL was not the result of direct reaction of these oxidants with the apolipoprotein. In vitro and in vivo enrichment of HDL with alpha-TOH resulted in a dose-dependent increase in the extent of peroxyl radical-induced formation of HDL cholesteryl ester hydroperoxides (r = 0.96) and cholesteryl ester hydroxides (r = 0. 92), as well as the loss of apoAI (r = 0.96) and apoAII (r = 0.94). alpha-TOH enrichment also enhanced HDL lipid and protein oxidation induced by Cu2+ or soybean lipoxygenase. These results indicate that the earliest stages of HDL oxidation are accompanied by the oxidation of specific methionine residues in apoAI and apoAII and that in the absence of co-antioxidants, alpha-TOH can promote this process.
Collapse
Affiliation(s)
- B Garner
- Biochemistry, The Heart Research Institute, Sydney New South Wales 2050, Australia
| | | | | | | | | | | |
Collapse
|
5
|
Bielicki JK, Forte TM, McCall MR. Minimally oxidized LDL is a potent inhibitor of lecithin:cholesterol acyltransferase activity. J Lipid Res 1996. [DOI: 10.1016/s0022-2275(20)42011-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
6
|
Bielicki JK, Forte TM, McCall MR. Gas-phase cigarette smoke inhibits plasma lecithin-cholesterol acyltransferase activity by modification of the enzyme's free thiols. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1258:35-40. [PMID: 7654778 DOI: 10.1016/0005-2760(95)00092-q] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cigarette smoking is associated with an increased risk of premature atherosclerosis. The underlying mechanisms responsible for this association are unknown. Recent work from this laboratory has shown that ex vivo exposure to plasma to gas-phase cigarette smoke (CS) produces a rapid inhibition of lecithin-cholesterol acyltransferase (LCAT) activity and crosslinking of HDL-apolipoproteins. The goal of the present study was to investigate the mechanism(s) by which CS inhibited LCAT and modified HDL. When dialyzed human plasma (12 ml) was exposed to the gas-phase of an equivalent of 1/8 of a cigarette (one 'puff') at 15 min intervals for 3 h, LCAT activity was reduced by 76 +/- 1% compared to controls; supplementation of plasma with glutathione produced a dose-dependent protection of LCAT activity where at the highest concentration (1 mM) 78% protection was observed. A similar protection was obtained with N-acetyl cysteine (1 mM). In addition to LCAT inhibition, HDL-apolipoproteins were crosslinked after 3 h exposure of plasma to CS; crosslinking was reduced by the addition of either glutathione or N-acetyl cysteine to plasma. The amino compounds N-acetyl lysine, N-acetyl arginine, and aminoguanidine failed to protect LCAT and HDL indicating a specificity with regard to the ability of free thiols to buffer the deleterious components of CS which inhibited LCAT and crosslinked HDL-apolipoproteins. Since LCAT contains two free cysteine residues (Cys-31 and -184) near the active site of the enzyme, we tested whether pretreatment of plasma with the reversible sulfhydryl modifying compound, 5,5'-dithiobis-2-nitrobenzoic acid (DTNB), could protect LCAT from CS-induced inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J K Bielicki
- Department of Molecular and Nuclear Medicine, University of California, Berkeley 94720, USA
| | | | | |
Collapse
|
7
|
McCall MR, van den Berg JJ, Kuypers FA, Tribble DL, Krauss RM, Knoff LJ, Forte TM. Modification of LCAT activity and HDL structure. New links between cigarette smoke and coronary heart disease risk. ARTERIOSCLEROSIS AND THROMBOSIS : A JOURNAL OF VASCULAR BIOLOGY 1994; 14:248-53. [PMID: 8305416 DOI: 10.1161/01.atv.14.2.248] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The mechanism(s) through which smoking influences the progression of atherosclerosis is poorly understood. Recent evidence suggests that oxidants present in the gas phase of cigarette smoke are involved. We exposed human plasma to the filtered gas phase of cigarette smoke to assess its effects on plasma components involved in the antiatherogenic reverse cholesterol transport pathway. In our model, freshly isolated plasma (24 mL) was exposed to filtered air or gas-phase cigarette smoke for up to 6 hours at 37 degrees C. Lecithin-cholesterol acyltransferase (LCAT) activity was dramatically inhibited by cigarette smoke. A single 15-minute exposure to the smoke from an eighth of a cigarette was sufficient to reduce LCAT activity by 7%; additional exposures resulted in further decreases in activity. At 6 hours, only 22% of control LCAT activity remained in plasma exposed to smoke. Compared with control, gas-phase cigarette smoke-exposed plasma possessed high-density lipoprotein (HDL) with increased (16%) negative charge and with cross-linked apolipoproteins AI and AII. These data demonstrate that gas-phase cigarette smoke can inhibit a key enzyme (LCAT) and modify an integral lipid transport particle (HDL) that are essential components for the normal function of the reverse cholesterol transport pathway. Gas-phase cigarette smoke-induced modification of the reverse cholesterol transport pathway may provide a new mechanistic link between cigarette smoke and coronary heart disease risk.
Collapse
Affiliation(s)
- M R McCall
- Department of Molecular and Nuclear Medicine, Lawrence Berkeley Laboratory, University of California, Berkeley 94720
| | | | | | | | | | | | | |
Collapse
|
8
|
|
9
|
Leblond L, Marcel Y. Uptake of high density lipoprotein cholesterol ester by HepG2 cells involves apolipoprotein E localized on the cell surface. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53904-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
10
|
Kilsdonk EP, van Gent T, Dorsman AN, van Tol A. Binding of modified high density lipoproteins to endothelial cells: relation with cellular cholesterol efflux? Atherosclerosis 1992; 97:131-42. [PMID: 1466659 DOI: 10.1016/0021-9150(92)90126-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Human endothelial cells (EA.hy 926 line) were enriched with cholesterol using cationized low density lipoprotein (LDL). Cholesterol-loaded cells interacted with native apolipoprotein (apo) E-free high density lipoprotein3 (HDL)3 as well as with dimethyl suberimidate-modified HDL3 (DMS-HDL3). At 4 degrees C both HDL preparations showed a saturable high affinity binding with a KD of 31 and 50 micrograms of protein/ml and a Bmax of 226 and 436 ng/mg cell protein for native HDL3 and DMS-HDL3 particles, respectively. Competition of binding of 5 micrograms apo E-free 125I-labelled HDL3/ml by unlabelled DMS-HDL3 and tetranitromethane-treated HDL3 (TNM-HDL3) was very poor, whereas unlabelled native HDL3 competed very effectively with 125I-labelled HDL3 binding. Thus, both types of modified HDL did not compete for the high affinity binding sites for native HDL. Unlabelled native HDL3 and unlabelled DMS-HDL3 both competed for the binding of 125I-labelled DMS-HDL3 very effectively. These experiments indicate that there are two distinct high affinity binding sites for HDL on cationized LDL-loaded EA.hy 926 cells: one specific HDL binding site, which only binds native HDL, and a second binding site for both native HDL and DMS-HDL. The modified HDL fractions were used to study the relation between HDL binding and HDL-mediated efflux. Efflux of cell cholesterol was measured as the increase of cholesterol mass in the medium after 24 h of incubation with 0.2 mg native HDL3/ml, or the same amount of modified HDL3. DMS-HDL3-mediated efflux was identical to efflux mediated by native HDL3. TNM-HDL3 also induced efflux of cell cholesterol; however, efflux induced by TNM-HDL3 was only 45-50% of the amount obtained with native HDL3. So both DMS- and TNM-modified HDL3 induced efflux of cholesterol, although these particles do not bind to the specific high affinity sites for native HDL. These results do not indicate a link between binding of HDL to specific receptors for native HDL and HDL-mediated efflux of cholesterol from loaded endothelial cells.
Collapse
Affiliation(s)
- E P Kilsdonk
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, The Netherlands
| | | | | | | |
Collapse
|
11
|
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)
Collapse
Affiliation(s)
- W J Johnson
- Department of Physiology and Biochemistry, Medical College of Pennsylvania, Philadelphia 19129
| | | | | | | |
Collapse
|
12
|
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
|