201
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Rentero C, Evans R, Wood P, Tebar F, Vilà de Muga S, Cubells L, de Diego I, Hayes TE, Hughes WE, Pol A, Rye KA, Enrich C, Grewal T. Inhibition of H-Ras and MAPK is compensated by PKC-dependent pathways in annexin A6 expressing cells. Cell Signal 2005; 18:1006-16. [PMID: 16183252 DOI: 10.1016/j.cellsig.2005.08.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 08/22/2005] [Accepted: 08/22/2005] [Indexed: 01/06/2023]
Abstract
High-density lipoprotein (HDL)-induced activation of the Ras/MAPK pathway can be mediated by protein kinase C (PKC)-dependent and independent pathways. Although both pathways co-exist in cells, we showed that binding of HDL to scavenger receptor BI (SR-BI) in CHO cells activates Ras and MAPK in a PKC-independent manner. We have recently identified that HDL-induced activation of Ras and Raf-1 is reduced in annexin A6 expressing CHO cells (CHOanx6). In the present study we demonstrate that despite the loss of Ras and Raf-1 activity, HDL induces MAPK phosphorylation in CHOanx6 cells. Since annexin A6 is a PKCalpha-binding protein we therefore investigated the possible involvement of PKC in HDL-induced Ras and MAPK activation in CHOanx6 cells. Taken together our findings demonstrate that HDL-induced H-Ras and MAPK activation is PKC-dependent in cells expressing annexin A6 to compensate for the loss of PKC-independent activation of H-Ras and MAPK.
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Affiliation(s)
- Carles Rentero
- Departament de Biologia Cellular, Facultat de Medicina, Universitat de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, and Centre for Immunology, St. Vincent's Hospital, Sydney, NSW, Australia
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202
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Navarro MA, Carpintero R, Acín S, Arbonés-Mainar JM, Calleja L, Carnicer R, Surra JC, Guzmán-García MA, González-Ramón N, Iturralde M, Lampreave F, Piñeiro A, Osada J. Immune-regulation of the apolipoprotein A-I/C-III/A-IV gene cluster in experimental inflammation. Cytokine 2005; 31:52-63. [PMID: 15878672 DOI: 10.1016/j.cyto.2005.03.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2004] [Revised: 03/04/2005] [Accepted: 03/23/2005] [Indexed: 01/26/2023]
Abstract
Apolipoprotein A-IV is a member of the apo A-I/C-III/A-IV gene cluster. In order to investigate its hypothetical coordinated regulation, an acute phase was induced in pigs by turpentine oil injection. The hepatic expression of the gene cluster as well as the plasma levels of apolipoproteins were monitored at different time periods. Furthermore, the involvement of the inflammatory mediators' interleukins 1 and 6 and tumor necrosis factor in the regulation of this gene cluster was tested in cultured pig hepatocytes, incubated with those mediators and apo A-I/C-III/A-IV gene cluster expression at the mRNA level was measured. In response to turpentine oil-induced inflammation, a decreased hepatic apo A-IV mRNA expression was observed (independent of apo A-I and apo C-III mRNA) not correlating with the plasma protein levels. The distribution of plasma apo A-IV experienced a shift from HDL to larger particles. In contrast, the changes in apo A-I and apo C-III mRNA were reflected in their corresponding plasma levels. Addition of cytokines to cultured pig hepatocytes also decreased apo A-IV and apo A-I mRNA levels. All these results show that the down-regulation of apolipoprotein A-I and A-IV messages in the liver may be mediated by interleukin 6 and TNF-alpha. The well-known HDL decrease found in many different acute-phase responses also appears in the pig due to the decreased expression of apolipoprotein A-I and the enlargement of the apolipoprotein A-IV-containing HDL.
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Affiliation(s)
- María A Navarro
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Facultad de Veterinaria, Universidad de Zaragoza, Miguel Servet 177, E-50013 Zaragoza, Spain
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203
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Robbesyn F, Augé N, Vindis C, Cantero AV, Barbaras R, Negre-Salvayre A, Salvayre R. High-density lipoproteins prevent the oxidized low-density lipoprotein-induced epidermal [corrected] growth factor receptor activation and subsequent matrix metalloproteinase-2 upregulation. Arterioscler Thromb Vasc Biol 2005; 25:1206-12. [PMID: 15817880 DOI: 10.1161/01.atv.0000164805.73558.80] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The atherogenic oxidized low-density lipoprotein (oxLDL) induces the formation of carbonyl-protein adducts and activates the epidermal [corrected] growth factor receptor (EGFR) signaling pathway, which is now regarded as a central element for signal transduction. We aimed to investigate whether and by which mechanism the anti-atherogenic high-density lipoprotein (HDL) prevents these effects of oxLDL. METHODS AND RESULTS In vascular cultured cells, HDL and apolipoprotein A-I inhibit oxLDL-induced EGFR activation and subsequent signaling by acting through 2 separate mechanisms. First, HDL, like the aldehyde scavenger dinitrophenyl hydrazine, prevented the formation of oxLDL-induced carbonyl-protein adducts and 4-hydroxynonenal (HNE)-EGFR adducts. Secondly, HDL enhanced the cellular antioxidant defenses by preventing (through a scavenger receptor class B-1 (SR-BI)-dependent mechanism) the increase of intracellular reactive oxygen species (ROS) and subsequent EGFR activation triggered by oxLDL or H2O2. A pharmacological approach suggests that this protective effect of HDL is independent of cellular glutathione level and glutathione peroxidase activity, but it requires catalase activity. Finally, we report that oxLDL upregulates both membrane type 1 (MT1)-matrix metalloproteinase-1 (MT1-MMP) and MMP-2 through an EGFR-dependent mechanism and that HDL inhibits these events. CONCLUSIONS HDLs block in vitro oxLDL-induced EGFR signaling and subsequent MMP-2 activation by inhibiting carbonyl adducts formation and cellular oxidative stress. These effects of HDL may participate to reduce cell activation, excessive remodeling, and alteration of the vascular wall.
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Affiliation(s)
- Fanny Robbesyn
- INSERM U-466 and Biochimie IFR-31, Faculty of Medicine, University Paul Sabatier, Toulouse, France
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204
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Wolfrum C, Poy MN, Stoffel M. Apolipoprotein M is required for prebeta-HDL formation and cholesterol efflux to HDL and protects against atherosclerosis. Nat Med 2005; 11:418-22. [PMID: 15793583 DOI: 10.1038/nm1211] [Citation(s) in RCA: 242] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Accepted: 01/19/2005] [Indexed: 11/09/2022]
Abstract
High-density lipoproteins (HDLs) are considered antiatherogenic because they mediate reverse cholesterol transport from the periphery to the liver for excretion and degradation. Here we show that mice deficient in apolipoprotein M (apoM), a component of the HDL particle, accumulated cholesterol in large HDL particles (HDL(1)) while the conversion of HDL to prebeta-HDL was impaired. Accordingly, apoM-deficient mice lacked prebeta-HDL, a subclass of lipid-poor apolipoproteins that serves as a key acceptor of peripheral cellular cholesterol. This deficiency led to a markedly reduced cholesterol efflux from macrophages to apoM-deficient HDL compared to normal HDL in vitro. Overexpression of apoM in Ldlr(-/-) mice protected against atherosclerosis when the mice were challenged with a cholesterol-enriched diet, showing that apoM is important for the formation of prebeta-HDL and cholesterol efflux to HDL, and thereby inhibits formation of atherosclerotic lesions.
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Affiliation(s)
- Christian Wolfrum
- The Laboratory of Metabolic Diseases, The Rockefeller University, 1230 York Avenue, New York, New York 10021, USA
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205
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von Eckardstein A, Hersberger M, Rohrer L. Current understanding of the metabolism and biological actions of HDL. Curr Opin Clin Nutr Metab Care 2005; 8:147-52. [PMID: 15716792 DOI: 10.1097/00075197-200503000-00007] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW A low concentration of HDL-cholesterol is an important risk factor for coronary heart disease. The purpose of this review is to summarize the novel functions of HDL that may protect not only from atherosclerosis, but also from inflammation-induced organ damage. RECENT FINDINGS HDL interacts with several cellular receptors and lipid transporters. The interactions of HDL or apolipoprotein A-I with the scavenger receptor BI or adenosine triphosphate binding cassette transporters A1, G1 and G4 induce cholesterol efflux. Apolipoproteins and enzymes carried by HDL exert antioxidative functions. Some oxidative modifications of apolipoprotein A-I, for example of tyrosine residues, may however interfere with anti-atherosclerotic activities. The interactions of HDL and lysosphingolipids therein with scavenger receptor BI and sphingolipid receptors, respectively, elicit signals activating the protein kinase Akt, which in turn is a regulator of apoptosis in beta, endothelial and smooth muscle cells as well as a regulator of nitric oxide production and adhesion molecule expression in endothelial cells. Other signal transduction cascades are also elicited by HDL, some of which induce cholesterol efflux or activate mitogen-activated protein kinases. SUMMARY Properties with respect to cytokine production, lipid oxidation, cholesterol efflux and reverse cholesterol transport make HDL a protective agent and thus an interesting therapeutic target in atherosclerosis and inflammation-induced organ damage.
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Affiliation(s)
- Arnold von Eckardstein
- Institute of Clinical Chemistry, University Hospital Zurich, Rämistrasse 100, CH 8091 Zurich, Switzerland.
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206
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Abstract
Amyloid-beta (Abeta) has for a long time been thought to play a central role in the pathogenesis of Alzheimer disease (AD). Analysis of available data indicates that Abeta possesses properties of a metal-binding apolipoprotein influencing lipid transport and metabolism. Protection of lipoproteins from oxidation by transition metals, synaptic activity and role in the acute phase response represent plausible physiological functions of Abeta. However, these important biochemical qualities which may critically influence the development of AD, have been largely ignored by mainstream AD researchers, making Abeta appear to be a "black sheep" in a "good apolipoprotein" family. New studies are needed to shed further light on the physiological role of Abeta in lipid metabolism in the brain.
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Affiliation(s)
- Anatol Kontush
- INSERM Unité 551, Hôpital de la Pitié, Pavilion Benjamin Delessert, 83, Bd de l'Hôpital, 75651 Paris Cedex 13, France.
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207
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Turk JR, Laughlin MH. Physical activity and atherosclerosis: which animal model? ACTA ACUST UNITED AC 2005; 29:657-83. [PMID: 15536667 DOI: 10.1139/h04-042] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Atherosclerosis is a progressive disease that is the most important single contributor to human cardiovascular morbidity and mortality. Epidemiologic studies show that physical activity, or routine exercise, reduces the risk of developing cardiovascular disease. The mechanisms through which exercise may function in primary or secondary prevention of atherosclerosis remain largely to be established. Most studies in humans are performed after the onset of clinical signs when disease is well advanced and the prescription of exercise is based on empirical evidence of benefit in secondary prevention. Animal models per-mit the study of the initiation and progression of preclinical stages of atherosclerosis. In order to provide information relevant to treatment and prevention, these models should mimic human disease and interactions of physical activity with disease processes as closely as possible. The purpose of this review is to compare animal models of atherosclerosis and to summarize the available data in those models in regard to the effects of exercise.
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Affiliation(s)
- James R Turk
- Dept. of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia 65211, USA
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208
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Wierzbicki AS. Have we forgotten the pivotal role of high-density lipoprotein cholesterol in atherosclerosis prevention? Curr Med Res Opin 2005; 21:299-306. [PMID: 15802001 DOI: 10.1185/030079905x26216] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The critical importance of high-density lipoprotein cholesterol (HDL-C) as an independent and predictive factor for coronary heart disease (CHD) has been increasingly recognised in treatment guidelines for prevention and treatment of cardiovascular disease. The association of low HDL-C with an increased incidence of CHD implies a critical role for raising HDL-C in protection against atherosclerotic disease. HDL-C appears to exert this effect via a number of mechanisms. HDL-C is involved in reverse cholesterol transport, prevents endothelial dysfunction and has anti-inflammatory, anti-oxidant and antithrombotic properties. Therapeutic interventions that increase HDL-C include statins, fibrates and nicotinic acid. Of these, nicotinic acid raises HDL-C more effectively than either statin or fibrate therapy and has been proven to reduce cardiovascular events in monotherapy studies. Preliminary clinical studies have shown that addition of nicotinic acid to primary statin therapy is safe, has proven beneficial effects on atherosclerosis and may also reduce the incidence of major coronary events. The available clinical evidence suggests that addition of nicotinic acid to primary lipid-lowering therapy has an important atheroprotective role in patients with or at risk of developing CHD.
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209
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Abstract
Plasma high-density lipoprotein cholesterol (HDL-C) concentrations are genetically determined to a great extent, and quantitative trait locus (QTL) analysis has been used to identify chromosomal regions containing genes regulating HDL-C levels. We discuss new genes found to participate in HDL metabolism. We also summarize 37 mouse and 30 human QTLs for plasma HDL-C levels, finding that all but three of the mouse QTLs have been confirmed by a second cross or a homologous human QTL, that the mouse QTL map is almost saturated because 92% of recently reported QTLs are repeats of those already found, and that 28 of the 30 human QTLs are located in regions homologous to mouse QTLs. This high degree of concordance between mouse and human QTLs suggests that the underlying genes may be the same. Strategies to more rapidly identify genes underlying mouse and human QTLs for HDL-C include focusing on the mouse and using mouse–human homologies, combining crosses, and haplotyping to narrow the region. Sequence analysis and expression studies can distinguish candidate genes consistent across multiple mouse crosses, and testing the candidate genes in human association studies can provide additional evidence for the candidacy of a gene. Together these strategies can accelerate the pace of finding genes that regulate HDL.
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Affiliation(s)
- Xiaosong Wang
- Jackson Laboratory, 600 Main St, Bar Harbor, ME 04609, USA.
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210
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Wardle EN. Cellular oxidative processes in relation to renal disease. Am J Nephrol 2005; 25:13-22. [PMID: 15668522 DOI: 10.1159/000083477] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Accepted: 12/03/2004] [Indexed: 12/24/2022]
Abstract
This article summarizes the biochemical processes that produce reactive oxygen species (ROS) and other mediators that account for 'oxidative stress'. Formation of ROS in signal transduction cascades is illustrated from studies of kidney cell systems. The pathophysiological implications for the nephrologist are then reviewed.
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211
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Mauger JF, Couture P, Paradis ME, Lamarche B. Comparison of the impact of atorvastatin and simvastatin on apoA-I kinetics in men. Atherosclerosis 2005; 178:157-63. [PMID: 15585213 DOI: 10.1016/j.atherosclerosis.2004.06.022] [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: 01/20/2004] [Revised: 06/01/2004] [Accepted: 06/03/2004] [Indexed: 11/27/2022]
Abstract
BACKGROUND The impact of simvastatin and atorvastatin, two HMG-CoA inhibitors, on plasma HDL-C concentrations has been shown to be inconsistent, simvastatin being reported to induce greater increases in HDL-C than atorvastatin. The physiological mechanisms underlying this diverging effect are still unknown. OBJECTIVES To compare the impact of simvastatin and atorvastatin on apoA-I kinetics in vivo. METHODS In this double-blind, cross-over study, seven men with relatively low baseline HDL-C were assigned in random order to one of two experimental 8-week treatments (atorvastatin 40 mg or simvastatin 80 mg), each separated by a 6-week washout period. After each phase, apoA-I kinetics were measured using a primed-constant infusion of l-(5,5,5-D3) leucine for 12 h with patients being kept in constant fed, steady state. Isotopic enrichment of apoA-I over time was assessed by gas chromatography-mass spectrometry and kinetic parameters were calculated by multicompartmental modeling. RESULTS Both treatments reduced plasma LDL-C levels to a similar extent while HDL-C levels remained statistically unchanged after both experimental phases. However, compared to atorvastatin, plasma apoA-I concentrations were significantly higher after treatment with simvastatin (1.33 +/- 0.07 g/L versus 1.23 +/- 0.07 g/L, P = 0.05). Treatment with simvastatin also induced a significant increase in apoA-I production rate compared to atorvastatin (15.2 +/- 3.0 mg/kg/d versus 13.2 +/- 2.6 mg/kg/d, P = 0.05). There was no statistical difference in apoA-1 fractional catabolic rate between simvastatin and atorvastatin (0.26 +/- 0.05 pool/d versus 0.24 +/- 0.04 pool/d). CONCLUSIONS These results suggest that the diverging impact of simvastatin and atorvastatin on plasma HDL-C levels in humans may be attributable, at least partly, to a greater production rate of apoA-I with simvastatin.
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Affiliation(s)
- Jean-François Mauger
- Institute on Nutraceuticals and Functional Foods, 2440 Boul Hochelaga, Local 2742, Laval University, Que., Canada G1K 7P4
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212
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Abstract
Atherosclerosis and related diseases are the leading cause of death in Western world. The disease process begins with the formation of fatty streaks already during the first decade of life but does not manifest clinically until several decades later. Gene therapy is a potential new way to target multiple factors playing a role in the development and progression of atherosclerosis. A great number of genes involved in the development of atherosclerosis have been identified and have been tested both in vitro and in vivo as potential new targets for therapy. Pre-clinical experiments have shown the feasibility and safety of several gene therapy applications for the treatment of atherosclerosis and clinical trials have also provided evidence for the applicability of gene therapy for the treatment of cardiovascular diseases. In this review we discuss vectors and potential gene therapy approaches for intervention and therapy of atherosclerosis.
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Affiliation(s)
- E Vähäkangas
- Department of Biotechnology and Molecular Medicine, AI Virtanen Institute for Molecular Sciences, Kuopio, Finland
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213
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Abstract
Many current treatment guidelines aimed at the prevention of cardiovascular events focus on low-density lipoprotein cholesterol (LDL-C) targets when addressing dyslipidaemia, and hence, indirectly at least, encourage the use of statin therapy. While this strategy shows marked clinical benefit, reducing cardiovascular risk by approximately 30%, there remains scope for greater treatment success. Recent analyses of data from epidemiological studies such as the Prospective Cardiovascular Münster (PROCAM) highlighted the importance of other lipid parameters of risk, such as a deficit of plasma high-density lipoprotein cholesterol (HDL-C) or an excess of lipoprotein (a) [Lp(a)]. HDL has been shown to be operative in a wide range of atheroprotective mechanisms beyond its well known role in reverse cholesterol transport, while Lp(a) is known to increase atherothrombotic responses. Both HDL and Lp(a) levels interact with other parameters of risk, including LDL-C, such as to greatly influence an individual's global risk. As a consequence, the International Task Force for Prevention of Coronary Heart Disease has recently produced guidelines that consider an individual's risk to result from both classical and emerging risk factors. HDL-C raising is advocated as a treatment strategy for at-risk patients with fasting triglyceride levels > or = 200 mg/dL (> or = 2.3 mmol/L) and HDL-C levels < 35 mg/dL (< 0.9 mmol/L). This strategy is supported by prospective epidemiological evidence. Lp(a) has not been specifically tested as a target for intervention, but it is included in the new guidelines where it is regarded as an important modifier of global risk.
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Affiliation(s)
- Gerd Assmann
- Institute of Clinical Chemistry and Laboratory Medicine, Westphalian Wilhelms-University, Muenster, Germany.
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214
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Marcil M, O'Connell B, Krimbou L, Genest J. High-density lipoproteins: multifunctional vanguards of the cardiovascular system. Expert Rev Cardiovasc Ther 2004; 2:417-30. [PMID: 15151487 DOI: 10.1586/14779072.2.3.417] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The plasma level of high-density lipoprotein (HDL)-cholesterol is inversely correlated with coronary artery disease, the leading cause of death worldwide. HDL particles are thought to mediate the uptake of peripheral cholesterol and, through exchange of core lipids with other lipoproteins or selective uptake by specific receptors, return this cholesterol to the liver for bile acid secretion or hormone synthesis in steroidogenic tissues. HDL particles also act on vascular processes by modulating vasomotor function, thrombosis, cell-adhesion molecule expression, platelet function, nitric oxide release, endothelial cell apoptosis and proliferation. Many of these effects involve signal transduction pathways and gene transcription. Several genetic disorders of HDLs have been characterized at the molecular level. The study of naturally occurring mutations has considerably enhanced understanding of the role of HDL particles. Some mutations causing HDL deficiency are associated with premature coronary artery disease, while others, paradoxically, may be associated with longevity. Modulation of HDL metabolism for therapeutic purposes must take into account, not only the cholesterol content of a particle but its lipid (especially phospholipid) composition, apolipoprotein content, size and charge. Current therapeutic strategies include the use of peroxisome proliferating activator receptor-alpha agonists (fibrates) that increase apolipoprotein AI production and increase lipoprotein lipase activity, statins that have a small effect on HDL-cholesterol but markedly reduce low-density lipoprotein-cholesterol, the cholesterol/HDL-cholesterol ratio and niacin that increases HDL-cholesterol. Potential therapeutic targets include inhibition of cholesteryl ester transfer protein, modulating the ATP-binding cassette A1 transporter, and decreasing HDL uptake by scavenger receptor-B1. Novel therapies include injection of purified apolipoprotien AI and short peptides taken orally, mimicking some of the biological effects of apolipoprotein AI.
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Affiliation(s)
- Michel Marcil
- McGill University Health Center, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, H3A 1A1 QC, Canada.
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215
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216
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Abstract
A low level of high-density lipoprotein cholesterol (HDL-C) is an important risk factor for cardiovascular disease. Epidemiological and clinical studies provide evidence that HDL-C levels are linked to rates of coronary events. The cardioprotective effects of HDL-C have been attributed to its role in reverse cholesterol transport, its effects on endothelial cells, and its antioxidant activity. Although some clinical trials suggest a benefit of raising HDL-C to reduce risk, further studies are needed, and HDL-C is still not considered a primary target of therapy in the National Cholesterol Education Program guidelines. However, HDL-C should be considered as part of the patient's overall profile of established risk factors in determining treatment strategies.
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Affiliation(s)
- Gerd Assmann
- Institute of Clinical Chemistry and Laboratory Medicine, Central Laboratory, Westphalian Wilhelms-University, Munster, Germany.
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217
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Hansel B, Giral P, Nobecourt E, Chantepie S, Bruckert E, Chapman MJ, Kontush A. Metabolic syndrome is associated with elevated oxidative stress and dysfunctional dense high-density lipoprotein particles displaying impaired antioxidative activity. J Clin Endocrinol Metab 2004; 89:4963-71. [PMID: 15472192 DOI: 10.1210/jc.2004-0305] [Citation(s) in RCA: 303] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A metabolic syndrome (MetS) phenotype is characterized by insulin-resistance, atherogenic dyslipidemia, oxidative stress, and elevated cardiovascular risk and frequently involves subnormal levels of high-density lipoprotein (HDL) cholesterol. We evaluated the capacity of physicochemically distinct HDL subfractions from MetS subjects to protect low-density lipoprotein against oxidative stress.MetS subjects presented an insulin-resistant phenotype, with central obesity and elevation in systolic blood pressure and plasma triglyceride, LDL-cholesterol, apolipoprotein B, glucose, and insulin levels. Systemic oxidative stress, assessed as plasma 8-isoprostanes, was significantly higher (3.7-fold) in MetS subjects (n = 10) compared with nonobese normolipidemic controls (n = 11). In MetS, small, dense HDL3a, 3b, and 3c subfractions possessed significantly lower specific antioxidative activity (up to -23%, on a unit particle mass basis) than their counterparts in controls. In addition, HDL2a and 3a subfractions from MetS patients possessed lower total antioxidative activity (up to -41%, at equivalent plasma concentrations). The attenuated antioxidative activity of small, dense HDL subfractions correlated with systemic oxidative stress and insulin resistance and was associated with HDL particles exhibiting altered physicochemical properties (core triglyceride enrichment and cholesteryl ester depletion). We conclude that antioxidative activity of small, dense HDL subfractions of altered chemical composition is impaired in MetS and associated with elevated oxidative stress and insulin resistance. Induction of selective increase in the circulating concentrations of dense HDL subfractions may represent an innovative therapeutic approach for the attenuation of high cardiovascular risk in MetS.
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Affiliation(s)
- Boris Hansel
- Dyslipoproteinemia and Atherosclerosis Research Unit, National Institute for Health and Medical Research, Institut National de la Santé et de la Recherche Médicale, Hôpital de la Pitié, 75013 Paris, France
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218
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Asztalos BF. High-density lipoprotein metabolism and progression of atherosclerosis: new insights from the HDL Atherosclerosis Treatment Study. Curr Opin Cardiol 2004; 19:385-91. [PMID: 15218401 DOI: 10.1097/01.hco.0000126979.41946.7e] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize the current understanding of the potentially antiatherogenic properties of high-density lipoprotein related to its different components. RECENT FINDINGS Recent findings on the role of the different high-density lipoprotein subspecies in reverse cholesterol transport, inflammation, endothelial dysfunction, and low-density lipoprotein oxidation are covered. Special emphasis is put on the heterogeneity of high-density lipoprotein and functional changes related to specific high-density lipoprotein particles with the potential therapeutic alterations of high-density lipoprotein metabolism. SUMMARY The diverse action of high-density lipoprotein observed could be explained by the heterogeneity of high-density lipoprotein particles with completely different composition and properties. The modification of specific high-density lipoprotein subpopulations to reach the maximum atheroprotective effects under various pathologic conditions bears great potential in lipid research.
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Affiliation(s)
- Bela F Asztalos
- Lipid Metabolism Laboratory, Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111, USA.
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219
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Rohrer L, Hersberger M, von Eckardstein A. High density lipoproteins in the intersection of diabetes mellitus, inflammation and cardiovascular disease. Curr Opin Lipidol 2004; 15:269-78. [PMID: 15166782 DOI: 10.1097/00041433-200406000-00006] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Low HDL-cholesterol, diabetes mellitus and elevated C-reactive protein as well as various inflammatory diseases are risk factors for coronary heart disease. Both diabetes mellitus and inflammation decrease HDL-cholesterol. We summarize recent findings on the mechanisms underlying low HDL-cholesterol in diabetes and inflammation, as well as on novel functions of HDL that may protect not only from atherosclerosis but also from diabetes mellitus and inflammation-induced organ damage. RECENT FINDINGS Elevated levels of non-esterified fatty acids and disturbed insulin action contribute to low HDL-cholesterol in diabetes mellitus by modifying lipolysis, apolipoprotein A-I production, as well as the activities of adenosine triphosphate-binding cassette transporter A1 and lipid transfer. Inflammation causes low HDL-cholesterol by increasing the activities of endothelial lipase and soluble phospholipase A2 and by replacing apolipoprotein A-I in HDL with serum amyloid A. HDL and lysosphingolipids therein have been identified as activators of the protein kinase Akt, which in turn is a regulator of apoptosis in beta-cells, endothelial cells, and smooth muscle cells, as well as a regulator of nitric oxide production and adhesion molecule expression in endothelial cells. SUMMARY The protective properties of HDL in cytokine production, lipid oxidation, cholesterol efflux and reverse cholesterol transport make HDL a protective agent in inflammation-induced organ damage including diabetes mellitus. However, inflammation and diabetes cause a decrease in HDL-cholesterol concentrations and impair HDL function, placing HDL into the centre of a vicious cycle that may escalate into diabetes mellitus, inflammation-induced organ damage and atherosclerosis.
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Affiliation(s)
- Lucia Rohrer
- Institute of Clinical Chemistry, University Hospital Zurich, Rämistrasse 100, CH-8091 Zurich, Switzerland
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220
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Martínez-González J, Escudero I, Badimon L. Simvastatin potenciates PGI2 release induced by HDL in human VSMC: effect on Cox-2 up-regulation and MAPK signalling pathways activated by HDL. Atherosclerosis 2004; 174:305-13. [PMID: 15136060 DOI: 10.1016/j.atherosclerosis.2004.01.037] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Revised: 01/26/2004] [Accepted: 01/28/2004] [Indexed: 10/26/2022]
Abstract
High density lipoproteins (HDL) induce prostacyclin (PGI(2)) release in vascular smooth muscle cells (VSMC) by up-regulation of cyclooxygenase-2 (Cox-2). Our goal was to analyse the mechanisms underlying this effect, and its potential modulation by HMG-CoA reductase inhibition in human VSMC. The contribution of mitogen-activated protein kinase (MAPK) signalling pathways was assessed by Western blot analysis and using specific inhibitors [PD098059 for p42/44 MAPK kinase (MEK); SB203580 for p38 MAPK or L-JNKI1 for c-Jun N-terminal kinase-1 (JNK-1)]. HDL-induced PGI(2) release was inhibited by rofecoxib (a specific Cox-2 inhibitor, 5 microM). HDL induced the early activation of p42 MAPK, p38 MAPK and JNK-1. p42/44 MAPK was the major pathway involved in both Cox-2 up-regulation and PGI(2) synthesis; p38 MAPK was also involved in both processes while JNK inhibition only affected PGI(2) synthesis. Pertussis toxin (an inhibitor of Galphai/Galphao proteins) prevented MAPK activation and inhibited both Cox-2 up-regulation and PGI(2) release. Genistein (a tyrosine kinase inhibitor) inhibited PGI(2) release without affecting MAPK activation or Cox-2 up-regulation. Simvastatin (0.1-1 microM) increased HDL-induced PGI(2) release ( approximately 45% at 1 microM) but did not significantly modify early MAPK activation or Cox-2 expression. Simvastatin alone did not significantly affect PGI(2) release. Our results suggest that mechanisms associated with G protein-coupled receptor activation, trigger Cox-2 up-regulation and PGI(2) release via multiple MAPK signalling pathways in VSMC. The mechanism is independent of tyrosine kinase receptors, although cytosolic tyrosine kinases could activate Cox-2 post-translationally. The potential contribution of HDL to vascular homeostasis, via increases in PGI(2) synthesis, could be enhanced by HMG-CoA reductase inhibitors.
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MESH Headings
- Analysis of Variance
- Blotting, Northern
- Blotting, Western
- Cells, Cultured
- Cyclooxygenase 2
- Drug Interactions
- Enzyme Activation/drug effects
- Epoprostenol/metabolism
- Humans
- Isoenzymes/drug effects
- Isoenzymes/metabolism
- Lipoproteins, HDL/pharmacology
- Membrane Proteins
- Mitogen-Activated Protein Kinase 1/drug effects
- Mitogen-Activated Protein Kinase 1/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Prostaglandin-Endoperoxide Synthases/drug effects
- Prostaglandin-Endoperoxide Synthases/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sensitivity and Specificity
- Signal Transduction
- Simvastatin/pharmacology
- Up-Regulation/drug effects
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Affiliation(s)
- José Martínez-González
- Centro de Investigación Cardiovascular, CSIC/ICCC-Hospital de la Santa Creu i Sant Pau, Avda. Sant Antoni Maria Claret #167, 08025 Barcelona, Spain
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221
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Faber K, Axler O, Dahlbäck B, Nielsen LB. Characterization of apoM in normal and genetically modified mice. J Lipid Res 2004; 45:1272-8. [PMID: 15102887 DOI: 10.1194/jlr.m300451-jlr200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel human apolipoprotein [apolipoprotein M (apoM)] was recently described and demonstrated to be a lipocalin. We have now examined apoM in wild-type mice and mice with genetically altered lipoprotein metabolism. Liver and kidney showed high mRNA expression, whereas spleen, heart, brain, and testis demonstrated low expression. ApoM gene expression was initiated on embryonic day 10. Western blot analysis of plasma suggested that mouse apoM, like its human counterpart, is secreted with a retained signal peptide, but unlike human apoM it is not glycosylated. Gel filtration of plasma showed apoM to be associated with HDL-sized particles in wild-type and apoA-I-deficient mice and with HDL- and LDL-sized particles in LDL receptor-deficient mice, whereas apoM was mainly found in VLDL-sized particles in high-fat, high-cholesterol-fed apoE-deficient mice. The plasma concentration of apoM was similar in wild-type, LDL receptor-deficient, and apoE-deficient mice but was reduced to 33% in apoA-I-deficient compared with wild-type mice (P = 0.007). These data suggest that apoM mainly associates with HDL in normal mice but also with the pathologically increased lipoprotein fraction in genetically modified mice. The substantially decreased apoM levels in apoA-I-deficient mice suggest a connection between apoM and apoA-I metabolism.
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Affiliation(s)
- Kirsten Faber
- Division of Clinical Chemistry, Department of Laboratory Medicine, University of Lund, University Hospital Malmo, S-20502 Malmo, Sweden
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222
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Fontana L, Meyer TE, Klein S, Holloszy JO. Long-term calorie restriction is highly effective in reducing the risk for atherosclerosis in humans. Proc Natl Acad Sci U S A 2004; 101:6659-63. [PMID: 15096581 PMCID: PMC404101 DOI: 10.1073/pnas.0308291101] [Citation(s) in RCA: 621] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Little is known regarding the long-term effects of caloric restriction (CR) on the risk for atherosclerosis. We evaluated the effect of CR on risk factors for atherosclerosis in individuals who are restricting food intake to slow aging. We studied 18 individuals who had been on CR for an average of 6 years and 18 age-matched healthy individuals on typical American diets. We measured serum lipids and lipoproteins, fasting plasma glucose and insulin, blood pressure (BP), high-sensitivity C-reactive protein (CRP), platelet-derived growth factor AB (PDGF-AB), body composition, and carotid artery intima-media thickness (IMT). The CR group were leaner than the comparison group (body mass index, 19.6 +/- 1.9 vs. 25.9 +/- 3.2 kg/m(2); percent body fat, 8.7 +/- 7% vs. 24 +/- 8%). Serum total cholesterol (Tchol), low-density lipoprotein cholesterol, ratio of Tchol to high-density lipoprotein cholesterol (HDL-C), triglycerides, fasting glucose, fasting insulin, CRP, PDFG-AB, and systolic and diastolic BP were all markedly lower, whereas HDL-C was higher, in the CR than in the American diet group. Medical records indicated that the CR group had serum lipid-lipoprotein and BP levels in the usual range for individuals on typical American diets, and similar to those of the comparison group, before they began CR. Carotid artery IMT was approximately 40% less in the CR group than in the comparison group. Based on a range of risk factors, it appears that long-term CR has a powerful protective effect against atherosclerosis. This interpretation is supported by the finding of a low carotid artery IMT.
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Affiliation(s)
- Luigi Fontana
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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223
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Viswambharan H, Ming XF, Zhu S, Hubsch A, Lerch P, Vergères G, Rusconi S, Yang Z. Reconstituted high-density lipoprotein inhibits thrombin-induced endothelial tissue factor expression through inhibition of RhoA and stimulation of phosphatidylinositol 3-kinase but not Akt/endothelial nitric oxide synthase. Circ Res 2004; 94:918-25. [PMID: 14988229 DOI: 10.1161/01.res.0000124302.20396.b7] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endothelial cells express negligible amounts of tissue factor (TF) that can be induced by thrombin, which is important for acute coronary syndromes. Recent research suggests that endothelial TF expression is positively regulated by RhoA and p38mapk, but negatively by Akt/endothelial nitric oxide synthase (eNOS) pathway. High-density lipoprotein (HDL) is atheroprotective and exerts antiatherothrombotic effect. This study investigated the effect of a reconstituted HDL (rHDL) on endothelial TF expression induced by thrombin and the underlying mechanisms. In cultured human umbilical vein and aortic endothelial cells, thrombin (4 U/mL, 4 hours) increased TF protein level, which was reduced by rHDL (0.1 mg/mL, 43% inhibition, n=3 to 7, P<0.01). Activation of RhoA but not p38mapk by thrombin was prevented by rHDL. rHDL stimulated Akt/eNOS pathway. The phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin or LY294002 abolished the activation of Akt/eNOS and reversed the inhibitory effect of rHDL on TF expression. Adenoviral expression of the active PI3K mutant (p110) reduced TF expression stimulated by thrombin without inhibiting RhoA activation, whereas expression of the active Akt mutant (m/p) further facilitated TF upregulation by thrombin. Moreover, a dominant-negative Akt mutant (KA) reduced thrombin's effect and did not reverse the rHDL's inhibitory effect on TF expression. Inhibition of eNOS by N(omega)-nitro-L-arginine methyl ester (100 micromol/L) did not affect the rHDL's effect. In conclusion, rHDL inhibits thrombin-induced human endothelial TF expression through inhibition of RhoA and activation of PI3K but not Akt/eNOS. These findings implicate a novel mechanism of antiatherothrombotic effects of HDL.
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Affiliation(s)
- Hema Viswambharan
- Department of Medicine, Divisions of Physiology, University of Fribourg, Fribourg, Switzerland
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224
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Ivanov GS, Kater JM, Jha SH, Stutius EA, Sabharwal R, Tricarico MD, Ginsburg GS, Ozer JS. Sp and GATA factors are critical for Apolipoprotein AI downstream enhancer activity in human HepG2 cells. Gene 2004; 323:31-42. [PMID: 14659877 DOI: 10.1016/j.gene.2003.08.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The factors that bind to the hepatic-specific human apolipoprotein AI (apoAI) 48-bp downstream enhancer (DSE) were identified and characterized by electrophoretic mobility shift assays. A significant homology was shown between the histone 4 (H4) promoters and the hepatic-specific human apoAI DSE at Sp1 and H4TF2 binding sites. Human HepG2 nuclear extracts were used to form four specific complexes with the DSE (referred to as apoAI DSE-1, -2, -3, and -4). The apoAI DSE-1 and -2 complexes showed similar binding specificity to the Sp/H4TF1 consensus site within the apoAI DSE. The apoAI DSE-1 complex was predominantly recognized by anti-Sp1 and Sp3 sera in gel shift assays, indicating that the DSE was recognized by multiple Sp family members. Nuclear extracts that were prepared from retinoic acid treated HepG2 cells showed increased levels of Sp factors in gel shift and Western blot assays. The apoAI DSE-2 complex was identified as H4TF1 and formed in the absence of magnesium chloride. The apoAI DSE-3 complex bound to a consensus GATA element within the DSE that was recognized by recombinant human GATA-6 as well. The apoAI DSE-3 complex was completely disrupted by a GATA-4 antibody in EMSA. GATA-4 and -6 were detected in nuclear extracts prepared from retinoic acid treated HepG2 cells using Western blot assays. The highest apoAI DSE-3 levels were observed with retinoic acid treated HepG2 cell nuclear extracts in EMSA. ApoAI DSE-4 is a multi-factor complex that includes an Sp/H4TF1 factor and either H4TF2 or apoAI DSE-3. Because apoAI DSE mutations revealed transcription defects in transient transfection assays, we conclude that the entire DSE sequence is required for full apoAI transcriptional activity in HepG2 cells.
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Affiliation(s)
- Gleb S Ivanov
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, 715 Albany Street, Building R-618, Boston, MA 02118, USA
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225
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Formato M, Farina M, Spirito R, Maggioni M, Guarino A, Cherchi GM, Biglioli P, Edelstein C, Scanu AM. Evidence for a Proinflammatory and Proteolytic Environment in Plaques From Endarterectomy Segments of Human Carotid Arteries. Arterioscler Thromb Vasc Biol 2004; 24:129-35. [PMID: 14592849 DOI: 10.1161/01.atv.0000104013.71118.53] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives
Based on previous observations on apolipoprotein(a), apo(a), in human unstable carotid plaques, we explored whether in the inflammatory environment of human atheroma, proteolytic events affect other hepatic and topically generated proteins in relation to the issue of plaque stability.
Methods and Results
Forty unstable and 24 stable plaques from endarterectomy segments of affected human carotid arteries were extracted with buffered saline (PBS) and then 6 mol/L guanidine-hydrochloride (GdHCl) to identify loosely and tightly bound products, respectively. The extracts were studied before and after ultracentrifugation at d 1.21 g/mL. In the extracts, the concentrations of interleukin (IL)-6, −8, and −18 were significantly higher in the unstable plaques and correlated to those of MMP-2 and MMP-9. By Western blots, both apoB and apo(a) were highly fragmented and mostly present in the d 1.21 bottom that also contained fragments of apoE (10 and 22 kDa), decorin, biglycan, and versican. Fragmentation was higher in the unstable plaques. In baseline plasmas, concentrations of lipids, lipoproteins, and ILs did not differ between patients with unstable and stable plaques.
Conclusions
In unstable and to a lesser extent in stable plaques, there is a proinflammatory and proteolytic microenvironment with the generation of fragments with potential pathobiological significance that requires investigation.
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Affiliation(s)
- Marilena Formato
- Dipartimento di Scienze Fisiologiche, Biochimiche e Cellulari, University of Sassari, Italy
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226
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Nofer JR, Feuerborn R, Levkau B, Sokoll A, Seedorf U, Assmann G. Involvement of Cdc42 signaling in apoA-I-induced cholesterol efflux. J Biol Chem 2003; 278:53055-62. [PMID: 14563854 DOI: 10.1074/jbc.m305673200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cholesterol efflux, an important mechanism by which high density lipoproteins (HDL) protect against atherosclerosis, is initiated by docking of apolipoprotein A-I (apoA-I), a major HDL protein, to specific binding sites followed by activation of ATP-binding cassette transporter A1 (ABCA1) and translocation of cholesterol from intracellular compartments to the exofacial monolayer of the plasma membrane where it is accessible to HDL. In this report, we investigated potential signal transduction pathways that may link apoA-I binding to cholesterol translocation to the plasma membrane and cholesterol efflux. By using pull-down assays we found that apoA-I substantially increased the amount of activated Cdc42, Rac1, and Rho in human fibroblasts. Moreover, apoA-I induced actin polymerization, which is known to be controlled by Rho family G proteins. Inhibition of Cdc42 and Rac1 with Clostridium difficile toxin B inhibited apoA-I-induced cholesterol efflux, whereas inhibition of Rho with Clostridium botulinum C3-exoenzyme exerted opposite effects. Adenoviral expression of a Cdc42(T17N) dominant negative mutant substantially reduced apoA-I-induced cholesterol efflux, whereas dominant negative Rac1(T17N) had no effect. We further found that two downstream effectors of Cdc42/Rac1 signaling, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK), are activated by apoA-I. Pharmacological inhibition of JNK but not p38 MAPK decreased apoA-I-induced cholesterol efflux, whereas anisomycin and hydrogen peroxide, two direct JNK activators, could partially substitute for apoA-I in its ability to induce cholesterol efflux. These results for the first time demonstrate activation of Rho family G proteins and stress kinases by apoA-I and implicate the involvement of Cdc42 and JNK in the apoA-I-induced cholesterol efflux.
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Affiliation(s)
- Jerzy-Roch Nofer
- Institut für Klinische Chemie und Laboratoriumsmedizin, Westfälische Wilhelms-Universität, D-48129 Münster, Germany.
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227
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Nofer JR, Geigenmüller S, Göpfert C, Assmann G, Buddecke E, Schmidt A. High density lipoprotein-associated lysosphingolipids reduce E-selectin expression in human endothelial cells. Biochem Biophys Res Commun 2003; 310:98-103. [PMID: 14511654 DOI: 10.1016/j.bbrc.2003.08.126] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adhesion and recruitment of blood monocytes, processes mediated by cell adhesion molecules including E-selectin, represent an early event in atherogenesis. High density lipoproteins (HDLs) were shown to inhibit cytokine-induced expression of adhesion molecules, but mechanisms underlying this effect are not fully understood. We here investigated the effects of sphingosylphosphorylcholine (SPC) and lysosulfatide (LSF), two lysosphingolipids associated with HDL, on TNF-alpha-induced E-selectin expression in human umbilical endothelial cells. We found that HDL, SPC, and LSF inhibited E-selectin expression both on mRNA and protein level. In addition, all three agents reduced the number of E-selectin molecules present on endothelial cell surface. The inhibitory effects of HDL, SPC, and LSF on TNF-alpha-induced E-selectin expression were partially reverted in the presence of suramin, an antagonist of lysosphingolipid receptor EDG-3, or pertussis toxin, an inhibitor of trimeric G proteins. In addition, inhibition of activation of protein kinase Akt with LY294002 but not inhibition of phosphatidylinositol-specific phospholipase C (PI-PLC) with U73122 abolished the restrictive effects of HDL-, SPC-, or LSF on E-selectin expression. We conclude that HDL-associated lysosphingolipids may at least partially account for the inhibitory effects of HDL on cytokine-induced expression of adhesion molecules, and that activations of G-protein-coupled receptors and protein kinase Akt are involved in this process.
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Affiliation(s)
- Jerzy-Roch Nofer
- Institut für Klinische Chemie und Laboratoriumsmedizin, Westfälische Wilhelms-Universität, Münster, Germany.
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228
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AbouGhalia AH, Khater LM, Abd El-Wahed MA, El-Badrawy MF. Lipoprotein (a) and lipid profile in neonates from mothers with three different types of diabetes mellitus. Clin Biochem 2003; 36:563-9. [PMID: 14563451 DOI: 10.1016/s0009-9120(03)00077-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The metabolic components in neonates may be affected by maternal diabetes mellitus. DESIGN AND METHODS To investigate the alterations in lipid metabolism and the possible atherogenic risk, the lipoprotein a (Lp a), apoproteins, lipid profile, glucose concentrations were measured (ELISA, immunodiffusion and enzymatic) in 77 cord blood samples from diabetic and healthy pregnant mothers. RESULTS The body weight, cord glucose and both apoproteins were increased in neonates of gestational and noninsulin dependent diabetic (GDM, NIDDM) than in neonates of nondiabetic mothers (NNDM). The Lp (a) was not correlated with the blood glucose and didn't significantly increase in the three neonates groups of diabetic mothers. The apo B/apo A1 and the LDL/HDL ratios were insignificantly increased in relation to the body weight. In neonates of diabetic mothers (NDM), only the blood glucose and Lp (a) differ between both sexes. CONCLUSION NDM may have disturbed lipid metabolism, which require special care to them and to their mothers during the prenatal period.
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Affiliation(s)
- Azza H AbouGhalia
- Biochemistry Department, Ain Shams Faculty Of Medicine, Cairo, Egypt.
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229
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Escudero I, Martínez-González J, Alonso R, Mata P, Badimon L. Experimental and interventional dietary study in humans on the role of HDL fatty acid composition in PGI2 release and Cox-2 expression by VSMC. Eur J Clin Invest 2003; 33:779-86. [PMID: 12925037 DOI: 10.1046/j.1365-2362.2003.01221.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND High-density lipoproteins (HDLs) induce prostacyclin (PGI2) release in vascular smooth muscle cells (VSMCs) by up-regulation of cyclooxygenase-2 (Cox-2). Our goal was to analyze the role of human HDL lipid moiety on Cox-2-dependent PGI2 synthesis in human VSMCs and to assess the impact that the intake of diets with different fatty acid composition exert on HDL-induced PGI2 release. MATERIALS AND METHODS Human VSMCs were treated with HDL or fatty acids in the presence or absence of different cell signalling inhibitors and PGI2 (by enzyme immunoassay) and Cox-2 protein levels (by Western blot) were analyzed. High-density lipoproteins were obtained from a plasma pool or from plasma of 12 volunteers subjected to a longitudinal dietary interventional study of three consecutive diets periods enriched in monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids n-6 (PUFA n-6) or n-3 (PUFA n-3). RESULTS High-density lipoprotein delipidation attenuated the effect of HDL on both PGI2 synthesis and Cox-2 up-regulation, while arachidonic acid (AA) but not other fatty acids mimicked the effects of HDL. Arachidonic acid induced PGI2 synthesis and Cox-2 expression through similar mechanisms to those activated by HDL [pertussis toxin-sensitive G proteins, p42/44 mitogen-activated protein kinase (MAPK), p38MAPK, and c-Jun N-terminal kinase-1 (JNK-1) pathways]. Finally, we observed that HDL from the PUFA n-3 dietary period induced lower PGI2 release than that from the PUFA n-6 period (64% vs. 100%). CONCLUSIONS Our results suggest that lipid moiety modulates HDL-induced PGI2 release/Cox-2 up-regulation in human VSMCs, and that changes in fatty acids as accomplished with the diet can modulate vascular PGI2 homeostasis.
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Affiliation(s)
- I Escudero
- Centro de Investigación Cardiovascular, CSIC/ICCC-Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
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230
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Ando Y, Shimizugawa T, Takeshita S, Ono M, Shimamura M, Koishi R, Furukawa H. A decreased expression of angiopoietin-like 3 is protective against atherosclerosis in apoE-deficient mice. J Lipid Res 2003; 44:1216-23. [PMID: 12671033 DOI: 10.1194/jlr.m300031-jlr200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
KK/Snk mice (previously KK/San) possessing a recessive mutation (hypl) of the angiopoietin-like 3 (Angptl3) gene homozygously exhibit a marked reduction of VLDL due to the decreased Angptl3 expression. Recently, we proposed that Angptl3 is a new class of lipid metabolism modulator regulating VLDL triglyceride (TG) levels through the inhibition of lipoprotein lipase (LPL) activity. In this study, to elucidate the role of Angptl3 in atherogenesis, we investigated the effects of hypl mutation against hyperlipidemia and atherosclerosis in apolipoprotein E knockout (apoEKO) mice. ApoEKO mice with hypl mutation (apoEKO-hypl) exhibited a significant reduction of VLDL TG, VLDL cholesterol, and plasma apoB levels compared with apoEKO mice. Hepatic VLDL TG secretion was comparable between both apoE-deficient mice. Turnover studies revealed that the clearance of both [3H]TG-labeled and 125I-labeled VLDL was significantly enhanced in apoEKO-hypl mice. Postprandial plasma TG levels also decreased in apoEKO-hypl mice. Both LPL and hepatic lipase activities in the postheparin plasma increased significantly in apoEKO-hypl mice, explaining the enhanced lipid metabolism. Furthermore, apoEKO-hypl mice developed 3-fold smaller atherogenic lesions in the aortic sinus compared with apoEKO mice. Taken together, the reduction of Angptl3 expression is protective against hyperlipidemia and atherosclerosis, even in the absence of apoE, owing to the enhanced catabolism and clearance of TG-rich lipoproteins.
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Affiliation(s)
- Yosuke Ando
- Medicinal Safety Research Laboratories, Sankyo Co., Ltd., 717, Horikoshi, Fukuroi, Shizuoka 437-0065, Japan.
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