51
|
Chen HH, Hosken BD, Huang M, Gaubatz JW, Myers CL, Macfarlane RD, Pownall HJ, Yang CY. Electronegative LDLs from familial hypercholesterolemic patients are physicochemically heterogeneous but uniformly proapoptotic. J Lipid Res 2007; 48:177-84. [PMID: 17015886 DOI: 10.1194/jlr.m500481-jlr200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A highly electronegative fraction of human plasma LDLs, designated L5, has distinctive biological activity that includes induction of apoptosis in bovine aortic endothelial cells (BAECs). This study was performed to identify a relationship between LDL density, electronegativity, and biological activity, namely, the induction of apoptosis in BAECs. Plasma LDLs from normolipidemic subjects and homozygotic familial hypercholesterolemia subjects were separated into five subfractions, with increasing electronegativity from L1 to L5, and into seven subfractions according to increasing density, D1 to D7. L1 to L5 were also separated according to density, and D1 to D7 were separated according to charge. The density profiles of L1 to L5 were similar (maximum density = 1.030 +/- 0.002 g/ml). Induction of apoptosis by all seven density subfractions was confined to the highly electronegative fraction, L5, and within each density subfraction the magnitude of apoptosis correlated with the L5 content. Electronegative LDL is heterogeneous with respect to density and composition, and induction of apoptosis is more strongly associated with LDL electronegativity than with LDL size or density.
Collapse
Affiliation(s)
- Hsin-hung Chen
- Section of Atherosclerosis and Lipoprotein Research, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | | | | | |
Collapse
|
52
|
Gloerich J, van den Brink DM, Ruiter JPN, van Vlies N, Vaz FM, Wanders RJA, Ferdinandusse S. Metabolism of phytol to phytanic acid in the mouse, and the role of PPARα in its regulation. J Lipid Res 2007; 48:77-85. [PMID: 17015885 DOI: 10.1194/jlr.m600050-jlr200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phytol, a branched-chain fatty alcohol, is the naturally occurring precursor of phytanic and pristanic acid, branched-chain fatty acids that are both ligands for the nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha). To investigate the metabolism of phytol and the role of PPARalpha in its regulation, wild-type and PPARalpha knockout (PPARalpha-/-) mice were fed a phytol-enriched diet or, for comparison, a diet enriched with Wy-14,643, a synthetic PPARalpha agonist. After the phytol-enriched diet, phytol could only be detected in small intestine, the site of uptake, and liver. Upon longer duration of the diet, the level of the (E)-isomer of phytol increased significantly in the liver of PPARalpha-/- mice compared with wild-type mice. Activity measurements of the enzymes involved in phytol metabolism showed that treatment with a PPARalpha agonist resulted in a PPARalpha-dependent induction of at least two steps of the phytol degradation pathway in liver. Furthermore, the enzymes involved showed a higher activity toward the (E)-isomer than the (Z)-isomer of their respective substrates, indicating a stereospecificity toward the metabolism of (E)-phytol. In conclusion, the results described here show that the conversion of phytol to phytanic acid is regulated via PPARalpha and is specific for the breakdown of (E)-phytol.
Collapse
Affiliation(s)
- J Gloerich
- Laboratory of Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma's Children's Hospital, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
53
|
Zhang B, Katafuchi R, Arishima H, Matsunaga A, Rye KA, Saku K. Effects of atorvastatin and apoA-I/phosphatidylcholine discs on triglyceride-rich lipoprotein subfractions as characterized by capillary isotachophoresis. Clin Chim Acta 2006; 373:55-61. [PMID: 16806136 DOI: 10.1016/j.cca.2006.04.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 04/27/2006] [Accepted: 04/30/2006] [Indexed: 12/31/2022]
Abstract
BACKGROUND The present study examined the effects of atorvastatin and the in vitro effect of apolipoprotein (apo) A-I/phosphatidylcholine (POPC) discs on charge-based triglyceride-rich lipoprotein (TRL) subfractions in a patient with type III hyperlipoproteinemia (HLP) and the apoE2/2 phenotype. METHODS Charge-based lipoprotein subfractions were characterized by capillary isotachophoresis (cITP). cITP analysis was performed using plasma that had been prestained with a lipophilic dye on a Beckman P/ACE MDQ system. RESULTS Treatment with atorvastatin for 4 weeks markedly decreased the slow (s)-migrating TRL subfraction and both fast- and slow-migrating low-density lipoprotein (LDL) subfractions, but did not affect the fast (f)-migrating TRL subfraction in this patient. ApoA-I/POPC discs consisted of two major charge-based subfractions that had the mobility of cITP fTRL and sTRL. Incubation of plasma from this patient in the presence of apoA-I/POPC discs caused not only a reduction in cITP fast- and intermediate-migrating HDL and an increase in cITP sHDL but also a reduction in fTRL and sTRL and an increase in sLDL. CONCLUSION Atorvastatin and apoA-I/POPC discs decreased cITP TRL subfractions in a complementary manner, suggesting that the combination of apoA-I/POPC discs and atorvastatin could be a promising therapeutic approach for hypertriglyceridemia.
Collapse
Affiliation(s)
- Bo Zhang
- Department of Cardiology, Fukuoka University School of Medicine, 7-45-1 Nanakuma Jonan-ku, Fukuoka 814-0180, Japan
| | | | | | | | | | | |
Collapse
|
54
|
Zhang B, Maeda N, Okada K, Tatsukawa M, Sawayama Y, Matsunaga A, Kumagai K, Miura SI, Nagao T, Hayashi J, Saku K. Association between fast-migrating low-density lipoprotein subfraction as characterized by capillary isotachophoresis and intima-media thickness of carotid artery. Atherosclerosis 2006; 187:205-12. [PMID: 16236285 DOI: 10.1016/j.atherosclerosis.2005.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2005] [Revised: 08/10/2005] [Accepted: 09/10/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND A mildly modified LDL subfraction that is characterized by an increased negative charge exists in plasma. This electronegative LDL separated by ion-exchange chromatography has been shown to be inflammatory and its proportion is increased in patients with hyperlipidemia and diabetes mellitus. The present study examined the association between the level of fast (f)-migrating LDL subfraction characterized by capillary isotachophoresis (cITP) and carotid-artery intima-media thickness (CA-IMT). METHODS AND RESULTS This study included 469 subjects who underwent a physical examination. CA-IMT was determined by high-resolution B-model ultrasonoraphy. Levels of charge-based LDL subfractions were measured by cITP on a Beckman P/ACE MDQ system. An increased serum LDL-C level and cITP fLDL level were associated with increased CA-IMT after adjusting for age. The extent of the associations between cITP fLDL and CA-IMT and between LDL-C and CA-IMT were similar as assessed by a receiver-operating characteristic curve analysis. LDL-C, triglyceride, and remnant-like particle cholesterol levels were independently correlated with cITP fLDL, and the LDL-C level had the strongest correlation with cITP fLDL. The association between the cITP fLDL level and CA-IMT was significant in the high LDL-C stratum but not in the low stratum, indicating that it is modified by the LDL-C level. The high-LDL-C-high-fLDL group had the highest relative risk for a high CA-IMT among the groups with each combination of LDL-C and cITP fLDL level. CONCLUSION The cITP fLDL level was associated with CA-IMT and its combination with the LDL-C level is a stronger indicator for a high CA-IMT.
Collapse
Affiliation(s)
- Bo Zhang
- Department of Cardiology, Fukuoka University School of Medicine, 7-45-1 Nanakuma Jonan-ku, Fukuoka 814-0180, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
55
|
Zhang B, Böttcher A, Imaizumi S, Noda K, Schmitz G, Saku K. Relation between charge-based apolipoprotein B-containing lipoprotein subfractions and remnant-like particle cholesterol levels. Atherosclerosis 2006; 191:153-61. [PMID: 16620837 DOI: 10.1016/j.atherosclerosis.2006.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 02/03/2006] [Accepted: 03/04/2006] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Both mildly modified LDL subfraction that carries a more-negative electric charge and remnant-like particles (RLP) are closely related to triglyceride (TG) levels. We examined the relation between the RLP-cholesterol (C) level and charge-based apolipoprotein (apo) B-containing lipoprotein subfractions as determined by capillary isotachophoresis (cITP) in patients with hypercholesterolemia. METHODS AND RESULTS cITP apo B lipoprotein subfractions were identified by analyzing plasma depleted of the related lipoproteins. While fast-migrating triglyceride-rich lipoprotein (fTRL) subfraction contained both chylomicrons and VLDL fraction, slow TRL (sTRL) only contained VLDL. cITP fLDL also contained VLDL fraction, i.e., beta-VLDL. Levels of cITP fTRL and sTRL were significantly correlated with serum levels of TG, RLP-C, apo C-II, and C-III. Levels of cITP sTRL were also correlated with apo E. Levels of cITP fLDL were positively correlated with not only LDL-C levels but also levels of TG, RLP-C, apo C-II, C-III, and E. CONCLUSION cITP fast LDL correlated with RLP-C levels and modified the relation between RLP-C and TG levels.
Collapse
Affiliation(s)
- Bo Zhang
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | | | | | | | | | | |
Collapse
|
56
|
Benítez S, Camacho M, Bancells C, Vila L, Sánchez-Quesada JL, Ordóñez-Llanos J. Wide proinflammatory effect of electronegative low-density lipoprotein on human endothelial cells assayed by a protein array. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1014-21. [PMID: 16753331 DOI: 10.1016/j.bbalip.2006.03.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 03/17/2006] [Accepted: 03/27/2006] [Indexed: 02/08/2023]
Abstract
Electronegative low-density lipoprotein (LDL(-)) is a modified subfraction of LDL present in plasma able to induce the release of interleukin 8 (IL-8) and monocyte chemotactic protein 1 (MCP-1) by human umbilical vein endothelial cells (HUVEC). To ascertain whether further inflammation mediator release could be induced by LDL(-), a protein array system was used to measure 42 cytokines and related compounds. Native LDL and LDL(-) isolated from normolipemic subjects were incubated for 24 h with HUVEC and culture supernatants were used to measure inflammation mediator release. The protein array revealed that IL-6, granulocyte/monocyte colony-stimulating factor (GM-CSF) and growth-related oncogene (GRO) release were increased by cultured HUVEC in response to LDL(-). LDL(-) enhanced production of IL-6 (4-fold vs. LDL(+)), GM-CSF (4-fold), GRObeta (2-fold) and GROgamma (7-fold) was confirmed by ELISA. Time-course experiments revealed that IL-6 was released earlier than the other inflammation mediators, suggesting a first-wave cytokine action. However, the addition of IL-6 alone did not stimulate the production of IL-8, MCP-1 or GM-CSF. Moreover, IL-8, MCP-1 or GM-CSF alone did not promote the release of the other inflammatory molecules. Modification of LDL(+) by phospholipase A(2)-mediated lipolysis or by loading with non-esterified fatty acids (NEFA) reproduced the action of LDL(-), thereby suggesting the involvement of NEFA and/or lysophosphatidylcholine in the release of these molecules. Our results indicate that LDL(-) promotes a proinflammatory phenotype in endothelial cells through the production of cytokines, chemokines and growth factors.
Collapse
Affiliation(s)
- Sònia Benítez
- Department of Biochemistry and Institut de Recerca, Hospital de la Santa Creu i Sant Pau, C/Antoni Maria Claret 167, 08025 Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
57
|
Saito T, Matsunaga A, Oikawa S. Impact of Lipoprotein Glomerulopathy on the Relationship Between Lipids and Renal Diseases. Am J Kidney Dis 2006; 47:199-211. [PMID: 16431249 DOI: 10.1053/j.ajkd.2005.10.017] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 10/05/2005] [Indexed: 12/18/2022]
Abstract
Lipoprotein glomerulopathy (LPG) is a unique entity of renal lipidosis characterized by peculiar histopathologic characteristics of lipoprotein thrombi and an abnormal plasma lipoprotein profile resembling type III hyperlipoproteinemia, with a marked increase in serum apolipoprotein E (apoE) concentrations. At present, 65 cases have been reported worldwide, although most patients are found in Japan and east Asian countries. Recently, we identified 4 types of novel apoE mutations associated with LPG. In particular, a mutation designated apoE Sendai, in which arginine 145 is substituted with proline, occurs in the majority of Japanese patients. The virus-mediated transduction of apoE Sendai resulting in the development of LPG in apoE-deficient mice confirms the etiologic role of apoE mutation in LPG. Conversely, experimental graft-versus-host disease induced in Fc receptor gamma-chain-deficient mice showed LPG-like lesions in glomeruli without apoE mutations. Considered together, we believe that intrinsic factors in the kidney also contribute to the induction of LPG. Today, apoE and related lipid abnormalities are reported to have an important role in the development of various renal diseases, eg, diabetic nephropathy and immunoglobulin A nephropathy. In this article, we review clinical and histopathologic features of LPG, describe the etiologic role of apoE variants and intrinsic renal factors, and discuss the impact of LPG on mechanisms of other renal diseases.
Collapse
Affiliation(s)
- Takao Saito
- Division of Nephrology and Rheumatology, Department of Internal Medicine, Fukuoka University School of Medicine, Fukuoka, Japan.
| | | | | |
Collapse
|
58
|
Damasceno NRT, Sevanian A, Apolinário E, Oliveira JMA, Fernandes I, Abdalla DSP. Detection of electronegative low density lipoprotein (LDL-) in plasma and atherosclerotic lesions by monoclonal antibody-based immunoassays. Clin Biochem 2005; 39:28-38. [PMID: 16310760 DOI: 10.1016/j.clinbiochem.2005.09.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 09/06/2005] [Accepted: 09/06/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES To produce a monoclonal antibody (MAb) against electronegative LDL (LDL-) for detecting this modified lipoprotein in blood plasma and tissues. DESIGN AND METHODS LDL- was isolated from human blood plasma and used as an antigen for immunization of Balb/c mice. Lymphocytes of immunized mice were fused with myeloma cells (SP2/0) to obtain the hybridomas. LDL- was detected in blood plasma and atherosclerotic lesions of humans and rabbits by MAb-based ELISA and immunohistochemistry, respectively. RESULTS LDL- concentrations were higher (P < 0.05) in the blood plasma of hypercholesterolemic subjects (HC, 248 +/- 77 mg/dL of total cholesterol) than in normolipidemic subjects (NL, 173 +/- 82 mg/dL of total cholesterol) and rabbits (HC, 250 +/- 15 mg/dL of cholesterol versus NL, 81 +/- 12 mg/dL of cholesterol). Moreover, LDL- was detected in the atherosclerotic lesions of humans and rabbits. CONCLUSION These MAb-based immunoassays are adequate to detect LDL- in biological samples and represent an important tool for investigating the role of LDL- in atherosclerosis.
Collapse
Affiliation(s)
- Nágila R T Damasceno
- Department of Nutrition, School of Public Health, University of São Paulo, SP, Brazil
| | | | | | | | | | | |
Collapse
|
59
|
Sánchez-Quesada JL, Benítez S, Pérez A, Wagner AM, Rigla M, Carreras G, Vila L, Camacho M, Arcelus R, Ordóñez-Llanos J. The inflammatory properties of electronegative low-density lipoprotein from type 1 diabetic patients are related to increased platelet-activating factor acetylhydrolase activity. Diabetologia 2005; 48:2162-9. [PMID: 16132957 DOI: 10.1007/s00125-005-1899-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Accepted: 05/31/2005] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS Chemical and biological characteristics of LDL(-) from type 1 diabetic subjects were analysed. The diabetic patients were studied during poor and optimised glycaemic control. MATERIALS AND METHODS Total LDL was subfractionated into electropositive LDL(+) and electronegative LDL(-) by anion exchange chromatography and the lipid and protein composition of the two determined. RESULTS LDL(-) differed from LDL(+) in that it had higher triglyceride, non-esterified fatty acids, apoE, apoC-III and platelet-activating factor acetylhydrolase (PAF-AH), as well as lower apoB relative content. No evidence of increased oxidation was observed in LDL(-). LDL(-) increased two-fold the release of interleukin 8 (IL-8) and monocyte chemotactic protein 1 (MCP-1) in endothelial cells, suggesting an inflammatory role. Optimisation of glycaemic control after insulin therapy decreased the proportion of LDL(-), but did not modify the composition of LDL subfractions, except for a decrease in PAF-AH activity in LDL(-). The possibility that LDL(-) could be generated by non-enzymatic glycosylation was studied. Fructosamine and glycated LDL content in LDL subfractions from type 1 diabetic patients was greater than in LDL subfractions isolated from normoglycaemic subjects, and decreased after glycaemic optimisation in both subfractions. However, no difference was observed between LDL(+) and LDL(-) before and after insulin therapy. CONCLUSIONS/INTERPRETATION These results provide evidence that LDL(-) is not produced by glycosylation. Nevertheless, LDL(-) from diabetic patients displays inflammatory potential reflected by the induction of chemokine release in endothelial cells. This proatherogenic effect could be related to the high PAF-AH activity in LDL(-).
Collapse
Affiliation(s)
- J L Sánchez-Quesada
- Department of Biochemistry, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
60
|
Zhang B, Kaneshi T, Ohta T, Saku K. Relation between insulin resistance and fast-migrating LDL subfraction as characterized by capillary isotachophoresis. J Lipid Res 2005; 46:2265-77. [PMID: 16061945 DOI: 10.1194/jlr.m500192-jlr200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The proportion of the electronegative low density lipoprotein [LDL(-)] subfraction, which is atherogenic, is increased in type 2 diabetes but is not reduced by glycemic control. Therefore, we evaluated the ability of a new technique, capillary isotachophoresis (cITP), to quantify charge-based LDL subfractions and examined the relation between insulin resistance and the cITP fast-migrating (f) LDL levels. Seventy-five 10-year-old boys were included. The two cITP LDL subfractions, fLDL and major LDL subfractions, were proportional to the LDL protein content within the range of 0.1-0.8 mg/ml LDL protein. Levels of cITP fLDL were positively correlated with triglyceride (TG) levels and negatively correlated with LDL size. Insulin resistance as assessed by the homeostasis model assessment (HOMA-IR) was positively correlated (P < 0.01) with cITP fLDL levels (r = 0.41). The relation between HOMA-IR and cITP fLDL levels depended on TG levels but was independent of body mass index and LDL size. cITP lipoprotein analysis is an accurate and sensitive method for quantifying charge-based LDL subfractions in human plasma, and insulin resistance is related to cITP fLDL independent of LDL size.
Collapse
Affiliation(s)
- Bo Zhang
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan. bozhang @fukuoka-u.ac.jp
| | | | | | | |
Collapse
|
61
|
Benítez S, Camacho M, Arcelus R, Vila L, Bancells C, Ordóñez-Llanos J, Sánchez-Quesada JL. Increased lysophosphatidylcholine and non-esterified fatty acid content in LDL induces chemokine release in endothelial cells. Relationship with electronegative LDL. Atherosclerosis 2005; 177:299-305. [PMID: 15530903 DOI: 10.1016/j.atherosclerosis.2004.07.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 06/17/2004] [Accepted: 07/22/2004] [Indexed: 10/26/2022]
Abstract
Electronegative low-density lipoprotein (LDL(-)) is a plasma-circulating LDL subfraction with proinflammatory properties that induces the production of chemokines in cultured endothelial cells. However, the specific mechanism of LDL(-)-mediated chemokine release is presently unknown. A characteristic feature of LDL(-) is an increased content of lysophosphatidylcholine (LPC) and non-esterified fatty acids (NEFA). The effect of increasing amounts of LPC and NEFA associated with LDL on the release of chemokines by endothelial cells was studied. Total LDL was subfractionated by anion-exchange chromatography in electropositive (LDL(+)) and LDL(-). LDL(-) contained two-fold more LPC and NEFA than LDL(+) and induced two- to four-fold more (p < 0.05) interleukin-8 (IL-8, 11.5 +/- 8.2 ng/10(5) cells) and monocyte chemotactic protein-1 (MCP-1, 10.8 +/- 3.8 ng/10(5) cells) release by human umbilical vein endothelial cells (HUVEC) than LDL(+) (IL-8: 3.4 +/- 1.5 ng/10(5) cells, MCP-1: 5.8 +/- 2.9 ng/10(5) cells). The content of LPC and NEFA in LDL(+) was increased by enzymatic treatment with secretory phospholipase A(2) (sPLA(2)) at 5 ng/mL or 20 ng/mL or by incubation with NEFA at 2 mmol/L. Modification of LDL(+) by both methods did not result in oxidative modification as demonstrated by the lack of change in antioxidants, conjugated dienes and malondialdehyde content. sPLA(2) treatment resulted in an increase in LPC and NEFA in LDL(+) which enhanced its ability to release IL-8 and MCP-1 by HUVEC in a concentration-dependent manner (sPLA(2)(5)-LDL; IL-8: 7.1 +/- 3.8ng/10(5) cells, MCP-1: 8.0 +/- 5.1 ng/10(5) cells; sPLA(2)(20)-LDL; IL-8: 20.8 +/- 11.2 ng/10(5) cells, MCP-1: 15.0 +/- 7.5 ng/10(5) cells). NEFA loading of LDL(+) also favored the release of IL-8 and MCP-1 (IL-8: 7.8 +/- 6.1 ng/10(5) cells, MCP-1: 8.4 +/- 2.7 ng/10(5) cells, p < 0.05 versus LDL(+)). These effects were observed when modified LDL(+) reached a content of LPC and/or NEFA similar that of LDL(-). These data indicate that non-oxidized polar lipids associated with LDL promote an inflammatory response in endothelial cells and suggest that increased NEFA and LPC could be involved in the inflammatory activity of LDL(-).
Collapse
Affiliation(s)
- Sònia Benítez
- Department of Biochemistry and Inflammation Mediators Laboratory, Institut de Recerca, Hospital de la Santa Creu i Sant Pau, C/ Antoni Maria Claret 167, Barcelona 08025, Spain
| | | | | | | | | | | | | |
Collapse
|
62
|
Benítez S, Villegas V, Bancells C, Jorba O, González-Sastre F, Ordóñez-Llanos J, Sánchez-Quesada JL. Impaired Binding Affinity of Electronegative Low-Density Lipoprotein (LDL) to the LDL Receptor Is Related to Nonesterified Fatty Acids and Lysophosphatidylcholine Content†. Biochemistry 2004; 43:15863-72. [PMID: 15595841 DOI: 10.1021/bi048825z] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The binding characteristics of electropositive [LDL(+)] and electronegative LDL [LDL(-)] subfractions to the LDL receptor (LDLr) were studied. Saturation kinetic studies in cultured human fibroblasts demonstrated that LDL(-) from normolipemic (NL) and familial hypercholesterolemic (FH) subjects had lower binding affinity than their respective LDL(+) fractions (P < 0.05), as indicated by higher dissociation constant (K(D)) values. FH-LDL(+) also showed lower binding affinity (P < 0.05) than NL-LDL(+) (K(D), sorted from lower to higher affinity: NL-LDL(-), 33.0 +/- 24.4 nM; FH-LDL(-), 24.4 +/- 7.1 nM; FH-LDL(+), 16.6 +/- 7.0 nM; NL-LDL(+), 10.9 +/- 5.7 nM). These results were confirmed by binding displacement studies. The impaired affinity binding of LDL(-) could be attributed to altered secondary and tertiary structure of apolipoprotein B, but circular dichroism (CD) and tryptophan fluorescence (TrpF) studies revealed no structural differences between LDL(+) and LDL(-). To ascertain the role of increased nonesterified fatty acids (NEFA) and lysophosphatidylcholine (LPC) content in LDL(-), LDL(+) was enriched in NEFA or hydrolyzed with secretory phospholipase A(2). Modification of LDL gradually decreased the affinity to LDLr in parallel to the increasing content of NEFA and/or LPC. Modified LDLs with a NEFA content similar to that of LDL(-) displayed similar affinity. ApoB structure studies of modified LDLs by CD and TrpF showed no difference compared to LDL(+) or LDL(-). Our results indicate that NEFA loading or phospholipase A(2) lipolysis of LDL leads to changes that affect the affinity of LDL to LDLr with no major effect on apoB structure. Impaired affinity to the LDLr shown by LDL(-) is related to NEFA and/or LPC content rather than to structural differences in apolipoprotein B.
Collapse
Affiliation(s)
- Sonia Benítez
- Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
63
|
Pereira EC, Bertolami MC, Faludi AA, Sevanian A, Abdalla DSP. Antioxidant effect of simvastatin is not enhanced by its association with alpha-tocopherol in hypercholesterolemic patients. Free Radic Biol Med 2004; 37:1440-8. [PMID: 15454283 DOI: 10.1016/j.freeradbiomed.2004.07.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Revised: 07/13/2004] [Accepted: 07/15/2004] [Indexed: 11/30/2022]
Abstract
Among the pleiotropic effects of statins, their antioxidant action may be involved in their protective effects. Thus, we investigated the antioxidant effect of simvastatin, associated or not with alpha-tocopherol, on levels of electronegative low-density lipoprotein (LDL-), nitrotyrosine, thiols (homocysteine, glutathione, cysteine, methionine), and lipid-soluble antioxidants in blood plasma of hypercholesterolemic subjects. In this study, 25 hypercholesterolemic subjects were treated for 2 months with simvastatin (20 mg/day) and with simvastatin (20 mg/day) + alpha-tocopherol (400 IU/day). Concentrations of thiols were determined by high-performance capillary electrophoresis-laser-induced fluorescene. Lipid-soluble antioxidants were determined by HPLC, and LDL-, and nitrotyrosine by ELISA. Simvastatin, independent of its association with alpha-tocopherol, reduced plasma concentrations of LDL-, nitrotyrosine, total cholesterol, and LDL cholesterol and the LDL cholesterol/HDL cholesterol ratio. Neither simvastatin nor simvastatin plus alpha-tocopherol altered plasma levels of the thiols analyzed. alpha-Tocopherol did not change the antioxidant effect of simvastatin on the levels of LDL- and nitrotyrosine in hypercholesterolemic subjects. The reduction of LDL- and nitrotyrosine by simvastatin seems to be related to the pleiotropic effects of this statin, and it may have an important protective effect against endothelial dysfunction and atherosclerosis.
Collapse
Affiliation(s)
- Edimar C Pereira
- Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Brazil
| | | | | | | | | |
Collapse
|
64
|
Abstract
PURPOSE OF REVIEW The occurrence in blood of an electronegatively charged LDL was described in 1988. During the 1990s reports studying electronegative LDL (LDL(-)) were scant and its atherogenic role controversial. Nevertheless, recent reports have provided new evidence on a putative atherogenic role of LDL(-). This review focuses on and discusses these new findings. RECENT FINDINGS In recent years, LDL(-) has been found to be involved in several atherogenic features through its action on cultured endothelial cells. LDL(-) induces the production of chemokines, such as IL-8 and monocyte chemotactic protein 1, and increases tumor necrosis factor-alpha-induced production of vascular cell adhesion molecule 1, with these molecules being involved in early phases of leukocyte recruitment. LDL(-) from familial hypercholesterolemic patients also decreases DNA synthesis and intracellular fibroblast growth factor 2 production, which may contribute to impaired angiogenesis and increased apoptosis. In addition, the preferential association of platelet-activating factor acetylhydrolase with LDL(-) has been reported, suggesting a proinflammatory role of this enzyme in LDL(-). SUMMARY Recent findings suggest that LDL(-) could contribute to atherogenesis via several mechanisms, including proinflammatory, proapoptotic and anti-angiogenesis properties. Further studies are required to define the role of LDL(-) in atherogenesis more precisely and to clarify mechanisms involved in endothelial cell activation.
Collapse
Affiliation(s)
- José Luis Sánchez-Quesada
- Biochemistry Department and Research Institute, Hospital de la Santa Creu i Sant Pau, C/Antoni Maria Claret 167, 08025 Barcelona, Spain
| | | | | |
Collapse
|
65
|
Benítez S, Ordóñez-Llanos J, Franco M, Marín C, Paz E, López-Miranda J, Otal C, Pérez-Jiménez F, Sánchez-Quesada JL. Effect of simvastatin in familial hypercholesterolemia on the affinity of electronegative low-density lipoprotein subfractions to the low-density lipoprotein receptor. Am J Cardiol 2004; 93:414-20. [PMID: 14969613 DOI: 10.1016/j.amjcard.2003.10.034] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2003] [Revised: 10/23/2003] [Accepted: 10/23/2003] [Indexed: 11/18/2022]
Abstract
The effect of simvastatin therapy on the biologic characteristics of the electronegative low-density lipoprotein (LDL) subfraction of patients with familial hypercholesterolemia (FH) was studied. Total LDL, isolated from FH plasma at 0, 3 and 6 months of simvastatin treatment, was subfractionated into electropositive LDL (LDL[+]) and electronegative LDL (LDL[-]) by anion exchange chromatography. LDL isolated from healthy normolipemic (NL) subjects was used as a control. The LDL(-) proportion was twofold higher in patients with FH than in NL subjects (17.6 +/- 1.6% vs 7.8 +/- 1.5%, respectively; p <0.05) and was progressively reduced by simvastatin therapy (15.7 +/- 1.6% at 3 months; 13.8 +/- 2.5% at 6 months; p <0.05). Both LDL subfractions from patients with FH had a higher relative cholesterol content and decreased apolipoprotein B and triglycerides than NL subfractions. Simvastatin progressively induced changes in lipid content of both LDL subfractions in patients with FH, and lipid composition was closer to these subfractions in NL subjects after 6 months of therapy. Binding displacement experiments in human fibroblasts demonstrated that LDL(-) from both groups of subjects had a lower affinity of binding to the LDL receptor that LDL(+). In addition, LDL(+) in patients with FH presented an intermediate binding affinity between LDL(-) and LDL(+) in NL subjects. Simvastatin-induced changes in LDL composition were accompanied by a progressive increase in affinity of LDL(+) and LDL(-) in patients with FH. After 6 months of therapy, LDL(+) in FH had an affinity similar to that of LDL(+) in NL subjects. The LDL(-)-induced release of chemokines interleukin-8 and monocyte chemotactic protein-1 from cultured endothelial cells was twofold higher compared with that of LDL(+). No difference in chemokine release between patients with FH and NL subjects or the effect of simvastatin were observed. We conclude that simvastatin therapy was able to modify LDL subfraction composition in subjects with FH and increase their affinity to the LDL receptor. This improvement could contribute to the observed reduction in LDL(-) proportion induced by simvastatin.
Collapse
Affiliation(s)
- Sonia Benítez
- Department of Biochemistry, Hospital de la Santa Creu i Sant Pau, and Department of Biochemisty and Molecular Biology, University Autònoma de Barcelona, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
66
|
Ziouzenkova O, Asatryan L, Sahady D, Orasanu G, Perrey S, Cutak B, Hassell T, Akiyama TE, Berger JP, Sevanian A, Plutzky J. Dual roles for lipolysis and oxidation in peroxisome proliferation-activator receptor responses to electronegative low density lipoprotein. J Biol Chem 2003; 278:39874-81. [PMID: 12878589 PMCID: PMC4231711 DOI: 10.1074/jbc.m306786200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Low density lipoprotein (LDL) exists in various forms that possess unique characteristics, including particle content and metabolism. One circulating subfraction, electronegative LDL (LDL(-)), which is increased in familial hypercholesterolemia and diabetes, is implicated in accelerated atherosclerosis. Cellular responses to LDL(-) remain poorly described. Here we demonstrate that LDL(-) increases tumor necrosis factor alpha (TNFalpha)-induced inflammatory responses through NF kappa B and AP-1 activation with corresponding increases in vascular cell adhesion molecule-1 (VCAM1) expression. LDL receptor overexpression increased these effects. In contrast, exposing LDL(-) to the key lipolytic enzyme lipoprotein lipase (LPL) reversed these responses, inhibiting VCAM1 below levels seen with TNFalpha alone. LPL is known to act on lipoproteins to generate endogenous peroxisomal proliferator-activated receptor alpha (PPAR alpha) ligand, thus limiting inflammation. These responses varied according to the lipoprotein substrate triglyceride content (very low density lipoprotein >> LDL > high density lipoprotein). The PPAR alpha activation seen with LDL, however, was disproportionately high. We show here that MUT LDL activates PPAR alpha to an extent proportional to its LDL(-) content. As compared with LDL(-) alone, LPL-treated LDL(-) increased PPAR alpha activation 20-fold in either cell-based transfection or radioligand displacement assays. LPL-treated LDL(-) suppressed NF kappa B and AP-1 activation, increasing expression of the PPAR alpha target gene I kappa B alpha, although only in the genetic presence of PPAR alpha and with intact LPL hydrolysis. Mass spectrometry reveals that LPL-treatment of either LDL or LDL(-) releases hydroxy-octadecadienoic acids (HODEs), potent PPAR alpha activators. These findings suggest LPL-mediated PPAR alpha activation as an alternative catabolic pathway that may limit inflammatory responses to LDL(-).
Collapse
Affiliation(s)
- Ouliana Ziouzenkova
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachussetts 02115
| | - Liana Asatryan
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Deanna Sahady
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachussetts 02115
| | - Gabriela Orasanu
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachussetts 02115
| | - Stephan Perrey
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachussetts 02115
| | | | | | | | | | - Alex Sevanian
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Jorge Plutzky
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachussetts 02115
- To whom correspondence should be addressed: Brigham and Women’s Hospital, 77 Av. Louis Pasteur, NRB 740, Boston, MA 02115. Tel.: 617-525-4361; Fax: 617-525-4380;
| |
Collapse
|
67
|
Benítez S, Sánchez-Quesada JL, Ribas V, Jorba O, Blanco-Vaca F, González-Sastre F, Ordóñez-Llanos J. Platelet-activating factor acetylhydrolase is mainly associated with electronegative low-density lipoprotein subfraction. Circulation 2003; 108:92-6. [PMID: 12821559 DOI: 10.1161/01.cir.0000072791.40232.8f] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Electronegative LDL [LDL(-)], a modified subfraction of LDL present in plasma, induces the release of interleukin-8 and monocyte chemotactic protein-1 from cultured endothelial cells. METHODS AND RESULTS We demonstrate that platelet-activating factor acetylhydrolase (PAF-AH) is mainly associated with LDL(-). LDL(-) had 5-fold higher PAF-AH activity than the nonelectronegative LDL subfraction [LDL(+)] in both normolipemic and familial hypercholesterolemic subjects. Western blot analysis after SDS-PAGE confirmed these results, because a single band of 44 kDa corresponding to PAF-AH appeared in LDL(-) but not in LDL(+). Nondenaturing polyacrylamide gradient gel electrophoresis demonstrated that PAF-AH was bound to LDL(-) regardless of LDL size. In accordance with the above findings, nonesterified fatty acids, a cleavage product of PAF-AH, were increased in LDL(-) compared with LDL(+). CONCLUSIONS The high PAF-AH activity observed in LDL(-) could be related to the proinflammatory activity of these lipoproteins toward cultured endothelial cells.
Collapse
Affiliation(s)
- Sonia Benítez
- Servei de Bioquímica and Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
68
|
Hwang J, Wang J, Morazzoni P, Hodis HN, Sevanian A. The phytoestrogen equol increases nitric oxide availability by inhibiting superoxide production: an antioxidant mechanism for cell-mediated LDL modification. Free Radic Biol Med 2003; 34:1271-82. [PMID: 12726915 DOI: 10.1016/s0891-5849(03)00104-7] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Estrogen replacement therapy (ERT) is reported to lower the incidence of cardiovascular disease in postmenopausal women. ERT also lowers the levels of oxidatively modified low-density lipoprotein (LDL). Because modified LDL can mediate the development of atherosclerosis by inflammatory processes, ERT may exert its LDL protective effect through enhanced antioxidant activity in vascular tissues. Plant sources of estrogenic compounds have been used as alternatives for ERT because they avoid a number of negative health effects produced by estrogen. In this study, the antioxidant properties of the soy isoflavone metabolite, equol (an estrogenic metabolite of daidzein) were studied. Equol has a greater antioxidant activity than the parent isoflavone compounds genistein and daidzein, found in high concentration in soy. Equol inhibits LDL oxidation in vitro and LDL oxidative modification by J774 monocyte/macrophages to LDL(-), an electronegative modified LDL found in human plasma. An antioxidant effect of equol was found to be mediated by inhibition of superoxide radical (O(2)(-*)) production and manifested through enhanced levels of free nitric oxide (NO) that prevents LDL modification. Thus, when NO levels were increased by donor agents, generators, or compounds that facilitate nitric oxide synthase activity, LDL(-) formation by J774 cells was strongly inhibited. Conversely, inhibition of NO production enhanced LDL(-) formation, and the combination of reduced NO and increased O(2)(-*) production yielded maximum LDL(-) formation. Pretreatment of cells with equol inhibited production of O(2)(-*) by J774 cells apparently via the inactivation of the reduced nicotinamide adenine dinucleotide phosphate oxidase complex. Decreased O(2)(-*) production resulted in increased free NO levels (but not total NO production) indicating that decreased reactions between O(2)(-*) and NO are an outcome of equol's antioxidant activity in cell culture.
Collapse
Affiliation(s)
- Juliana Hwang
- School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA.
| | | | | | | | | |
Collapse
|
69
|
Young IS, Nicholls DP. Lipid metabolism. Curr Opin Lipidol 2002; 13:693-5. [PMID: 12441894 DOI: 10.1097/00041433-200212000-00014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|