A New Anti-oxidized LDL Monoclonal Antibody that Recognizes Foam Cells

Itabe, Hiroyuki; Takeshima, Eiji; Iwasaki, Hitomi; Kimura, Junji; Yoshida, Yasuhiko; Imanaka, Tsuneo; Takano, Tatsuya

doi:10.5551/jat1973.22.4_275

Cited by 15 publications

(23 citation statements)

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“…In support of this, addition of 18:2 to LDL previously exposed to rhLO for 60 min failed to result in further accumulation of 13-(S)(Z,E)-H(P)ODE. 3 Earlier studies noted that LDL lipid oxidation induced by various 15-LO did not display this characteristic self-inactivation (11)(12)(13)(14). It is well established that FFA peroxyl radicals are released from the active site of 15-LO during enzymic formation of 13-(S)(Z,E)-HPODE (21,38) and that this can lead to the co-oxidation of various compounds, including phenolic antioxidants, PL, cholesterol, and proteins (37,39).…”

Section: -Lipoxygenase-induced Oxidation Of Ldl Fatty Acids and Estersmentioning

confidence: 99%

“…Oxidation of low density lipoprotein (LDL) 1 in the arterial intimal space, by an as yet undefined process, is widely believed to participate in the process of atherogenesis (1)(2)(3)(4)(5). 15-Lipoxygenase (15-LO) has been implicated as an in vivo oxidant of LDL based on the presence in human atherosclerotic lesion of its mRNA, protein (6), and stereospecific lipid oxidation products (7)(8)(9).…”

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confidence: 99%

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Oxidation of Free Fatty Acids in Low Density Lipoprotein by 15-Lipoxygenase Stimulates Nonenzymic, α-Tocopherol-mediated Peroxidation of Cholesteryl Esters

Upston

Neužil

Witting

et al. 1997

Journal of Biological Chemistry

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15-Lipoxygenase has been implicated in the in vivo oxidation of low density lipoprotein (LDL) a process thought to be important in the origin and/or progression of human atherogenesis. We have suggested previously that oxidation of LDL's cholesteryl esters (CE) and phospholipids by soybean (SLO) or human recombinant 15-lipoxygenase (rhLO) can be ascribed largely to ␣-tocopherol (␣-TOH)-mediated peroxidation (TMP). In this study we demonstrate that addition to LDL of unesterified linoleate (18:2), other free fatty acid (FFA) substrates, or phospholipase A 2 (PLA 2 ) significantly enhanced the accumulation of CE hydro(pero)xides (CE-O(O)H) induced by rhLO, whereas the corresponding CE and nonsubstrate FFA were without effect. The enhanced CE-O(O)H accumulation showed a dependence on the concentration of free 18:2 in LDL. In contrast, addition of 18:2 had little effect on LDL oxidation induced by aqueous peroxyl radicals or Cu 2؉ ions. Analyses of the regio-and stereoisomers of oxidized 18:2 in SLO-treated native LDL demonstrated that the small amounts of 18:2 associated with the lipoprotein were oxidized enzymically and within minutes, whereas cholesteryl linoleate (Ch18:2) was oxidized nonenzymically and continuously over hours. ␣-Tocopheroxyl radical (␣-TO ⅐ ) formed in LDL exposed to SLO was enhanced by addition of 18:2 or PLA 2 . With rhLO and 18:2-supplemented LDL, oxidation of 18:2 was entirely enzymic, whereas that of Ch18:2 was largely, though not completely, nonenzymic. The small extent of enzymic Ch18:2 oxidation increased with increasing enzyme to LDL ratios. Ascorbate and the reduced form of coenzyme Q, ubiquinol-10, which are both capable of reducing ␣-TO ⅐ and thereby preventing TMP, inhibited nonenzymic Ch18:2 oxidation induced by rhLO. Trolox and ascorbyl palmitate, which also inhibit TMP, ameliorated both enzymic and nonenzymic oxidation of LDL's lipids, whereas probucol, a radical scavenger not capable of preventing TMP, was ineffective. These results demonstrate that rhLO-induced oxidation of CE is largely nonenzymic and increases with LDL's content of FFA substrates. We propose that conditions which increase LDL's FFA content, such as the presence of lipases, increase 15-LO-induced LDL lipid peroxidation and that this process requires only an initial, transient enzymic activity.

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Section: -Lipoxygenase-induced Oxidation Of Ldl Fatty Acids and Estersmentioning

confidence: 99%

mentioning

confidence: 99%

Oxidation of Free Fatty Acids in Low Density Lipoprotein by 15-Lipoxygenase Stimulates Nonenzymic, α-Tocopherol-mediated Peroxidation of Cholesteryl Esters

Upston

Neužil

Witting

et al. 1997

Journal of Biological Chemistry

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“…5) Mice were immunized with homogenates of human atheroma, and hybridomas were prepared by fusing myeloma cells and splenic cells from the immunized mice. Hybridomas were selected by the reactivity in the culture medium to copper-induced OxLDL on ELISA assay.…”

Section: Determination Of Oxldl In Plasmamentioning

confidence: 99%

“…We have developed a method to determine OxLDL in human plasma samples using a sandwich ELISA procedure with an anti-OxLDL monoclonal antibody. 5,6) Using this method, plasma OxLDL levels were found to increase in certain pathological conditions including acute myocardial infarction and carotid artery atherosclerosis. [6][7][8][9][10][11] Accumulation of OxLDL in atherosclerotic lesions was also demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Oxidized Low-density Lipoproteins: What Is Understood and What Remains to Be Clarified.

Itabe

2003

Biological & Pharmaceutical Bulletin

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127

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Oxidized low-density lipoprotein (OxLDL) has previously been thought to promote atherogenesis through foam cell formation. However, the actual nature of OxLDL present in vivo remained obscure until recently. We have produced a monoclonal antibody, DLH3, which specifically binds to OxLDL but not to native LDL. The presence of OxLDL in the LDL fraction of human plasma was demonstrated by introducing a sandwich ELISA procedure using DLH3 together with an anti-apoB antibody. Furthermore, OxLDL levels appeared to increase in certain pathological conditions including acute myocardial infarction and carotid artery atherosclerosis. Accumulation of OxLDL in atherosclerotic lesions has also been demonstrated by immunohistochemical and biochemical studies using the DLH3 antibody. This antibody recognizes oxidized phosphatidylcholines (OxPC) generated during oxidative modification of LDL, and OxPC-apoB adducts formed in OxLDL are the presumed antigens. Measuring OxLDL in plasma would be a useful diagnostic tool for cardiovascular diseases. However, there still remain some major questions related to OxLDL, the answers to which are crucial for understanding the mechanisms of atherogenesis.Key word atherosclerosis; oxidized low-density lipoprotein (LDL); foam cell; oxidized phosphatidylcholine; macrophage contact. A mesh-shaped sheet of elastin called elastic lamina lies between the endothelial cells and the layers of smooth muscle cells. There is accumulation of collagen fibers and lipids, and invasion of various cells including macrophages between the endothelial cells and the elastic lamina in the earliest stages of atherosclerotic lesions, which is referred as to as diffuse intimal thickening (Fig. 1b). Fatty streaks are macroscopic lumps on the vessel walls which coalesce to form long lesions. In this stage, there is massive acculumation of lipids in intimal areas and large numbers of macrophage-derived foam cells are found. Some foam cells are generated from smooth muscle cells (Fig. 1c). Fibrous caps are formed with smooth muscle cells and numerous fibrous proteins such as collagens are found in atheromata. In the deep regions of the atheroma, massive accumulations of macrophages, smooth muscle cells and extracellular matrix proteins are found (Fig. 1d).When the luminal surface of the atherosclerotic lesion is damaged or cracked, platelets immediately adhere and aggregate at the cracked sites and subsequently generate thrombi (Fig. 1e). Thrombus formation can lead to complete occlusion of the blood vessel, and is the primary cause of myocardial and cerebral infarction. From a number of research findings it has been presumed that atheromatous lesions enriched with lipids or foam cells become vulnerable and prone to rupture.Russel Ross proposed the so-called "modified injury-response hypothesis" as a possible mechanism of development of atheroslcerosis.22) When endothelial cells are injured or stressed, they respond to the injury by inducing various cytokines. Then, the cytokines activate other types of cells such as macr...

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“…[5][6][7][8][9][10] We have found that macrophages bind oxidatively damaged erythrocytes, [11][12][13][14] polymorphonuclear leukocytes, 15) and T-lymphoid cell line Jurkat cells, [16][17][18] and this recognition is due to the lectin-like receptors on the macrophage cell surface for sialylated poly-N-acetyllactosaminyl sugar chains on the oxidized cells. 13,[15][16][17][18][19][20] Upon oxidation of these cells, band 3 or CD43 glycoproteins bearing sialylated poly-N-acetyllactosaminyl sugar chains on the cell surface aggregate and the sugar chains in a higher density are more readily recognized by macrophages in the absence of serum.…”

mentioning

confidence: 99%

Water-soluble Antioxidants Inhibit Macrophage Recognition of Oxidized Erythrocytes.

Beppu¹,

Watanabe²,

Yokota³

et al. 2001

Biological & Pharmaceutical Bulletin

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Oxidative damage of cells and components in living bodies is one of the possible means of damage that can take place in vivo. [1][2][3] Recognition and phagocytic removal of damaged components or cells is an important function of macrophages in maintaining homeostasis.4) It is known that macrophages avidly bind and take up oxidized low density lipoprotein through the scavenger receptors on the cell surface, which may lead to the accumulation of lipid-laden foam cells in the artery wall in atherosclerotic lesions. [5][6][7][8][9][10] We have found that macrophages bind oxidatively damaged erythrocytes, [11][12][13][14] polymorphonuclear leukocytes, 15) and T-lymphoid cell line Jurkat cells, [16][17][18] and this recognition is due to the lectin-like receptors on the macrophage cell surface for sialylated poly-N-acetyllactosaminyl sugar chains on the oxidized cells. 13,[15][16][17][18][19][20] Upon oxidation of these cells, band 3 or CD43 glycoproteins bearing sialylated poly-N-acetyllactosaminyl sugar chains on the cell surface aggregate and the sugar chains in a higher density are more readily recognized by macrophages in the absence of serum. The presence of the lectin-like receptors on macrophages has been demonstrated. 14,16,18) In the previous study, we have demonstrated that antioxidants at relatively high concentrations inhibited macrophage functions, i.e., binding of oxidized low density lipoprotein, foam cell formation and accumulation of cholesterol, and suggested that the scavenger receptor activity of macrophages is exerted by oxidative mechanisms. 21) In the present study, whether oxidative mechanisms were also involved in macrophage recognition of oxidized erythrocytes through the lectin-like receptors was examined by preincubation of macrophages with water-soluble antioxidants. It was found that the recognition of macrophages for oxidized erythrocytes was inhibited by ascorbic acid-related compounds, catechin compounds and thiol-related compounds, suggesting the involvement of oxidative mechanisms in the macrophage lectin-like receptor recognition for these erythrocytes. MATERIALS AND METHODSMaterials Hanks' balanced salt solution (HBSS) and N-2-hyroxyethyl-piperazine-NЈ-2-ethanesulfonic acid (HEPES) (pH 7.2) were obtained from Nissui Pharmaceutical Co., Tokyo, and Dojindo Laboratories, Kumamoto, respectively. Thioglycollate medium was obtained from Difco Laboratories, Detroit, MI, U.S.A. RPMI 1640 medium and penicillinstreptomycin solution were obtained from Gibco Laboratories, Grand Island, NY, U.S.A. Glutathione (GSH), oxidized glutathione (GSSG) and L-buthionine-[S,R]-sulfoximine (buthionine sulfoximine, BSO) were obtained from Sigma Chemical Company, St. Louis, MO, U.S.A. Epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECg), and epigallocatechin gallate (EGCg) were obtained from Funakoshi, Tokyo. Dehydroascorbic acid (DHA) was from Aldrich Chemical, Milwaukee, MI, U.S.A. N-Acetylcysteine (NAC), L-ascorbic acid (ascorbic acid, ASA), erythorbic acid (ERA), Mayer's hematoxylin solu...

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A New Anti-oxidized LDL Monoclonal Antibody that Recognizes Foam Cells

Cited by 15 publications

References 0 publications

Oxidation of Free Fatty Acids in Low Density Lipoprotein by 15-Lipoxygenase Stimulates Nonenzymic, α-Tocopherol-mediated Peroxidation of Cholesteryl Esters

Oxidation of Free Fatty Acids in Low Density Lipoprotein by 15-Lipoxygenase Stimulates Nonenzymic, α-Tocopherol-mediated Peroxidation of Cholesteryl Esters

Oxidized Low-density Lipoproteins: What Is Understood and What Remains to Be Clarified.

Water-soluble Antioxidants Inhibit Macrophage Recognition of Oxidized Erythrocytes.

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