Metabolism of Oxidized Low Density Lipoprotein by Lecithin-Colesterol Acyltransferse

卵磷脂-胆固醇酰基转移酶对氧化低密度脂蛋白的代谢

• 批准号: 10672056
• 负责人: TAKANO Tatsuya
• 金额: $ 1.73万
• 依托单位: Teikyo University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10672056/
• 关键词: atherosclerosis; oxidized LDL; lipoprotein; oxidized PC; monoclonal antibody; foam cell; LCAT; 過酸化脂質; マクロファージ

The possible involvement of lecithin-cholesterol acyltransferase (LCAT) in the metabolism of oxidized phosphatidylcholine (PC) in plasma was investigated. A variety of oxidized products are formed from PC following oxidation of low density lipoproteins (LDL). A significant increase in LDL oxidation levels in patients with familial LCAT deficiency (FLD) has been previously demonstrated by a sensitive sandwich ELISA for oxidized LDL using the monoclonal antibody DLH3 which recognizes oxidized products of PC. In the present study, we found that LCAT produces various metabolites from oxidized PC and that oxidized PC molecules in LDL particles serve as substrates. When the neutral lipid fraction was separated by TLC after the incubation of oxidized 1-palmitoyl-2-[1 ィイD114ィエD1C] linoleoyl PC with human plasma, a number of radioactive bands were formed in addition to cholesteryl ester. These products were not formed from native 1-palmitoyl-2-[1-ィイD114ィエD1C] linoleoyl PC. Plasma from FLD patie … More nts also failed to form the additional products from oxidized PC. The addition of dithio-bis(nitrobenzoate) (DTNB), an LCAT inhibitor, or the inactivation of LCAT activity by treating the plasma at 56 C for 30 min abolished the generation of these products from oxidized PC. The activity was recovered in the high density lipoprotein (HDL) fraction but not in the LDL fraction separated from normal plasma. When 1-palmitoyl-2-[1-ィイD114ィエD1C] (9-oxononanoyl) PC and 1-stearoyl-2-[1-ィイD114ィエD1C] (5-oxovaleroyl) PC, PC oxidation products that contain short chain aldehydes, were incubated with human plasma, radioactive products in the neutral lipid fraction were observed on TLC. LDL containing oxidized PC was measured by sandwich ELISA using an anti-apolipoprotein B antibody and DLH3.The reconstituted oxidized PC-LDL particles were found to have lost their ability to bind DLH3 upon incubation with HDL, while the reactivity of the reconstituted oxidized PC-LDL remained unchanged in the presence of DTNB. These results suggest that LCAT is capable of metabolizing a variety of oxidized products of PC and preventing the accumulation of oxidized PC in circulating LDL particles. Less

研究了卵磷脂胆固醇酰基转移酶（LCAT）可能参与血浆中氧化磷脂酰胆碱（PC）的代谢。低密度脂蛋白 (LDL) 氧化后，PC 会形成多种氧化产物。先前已通过使用识别 PC 氧化产物的单克隆抗体 DLH3 对氧化 LDL 进行敏感夹心 ELISA 证明，患有家族性 LCAT 缺陷 (FLD) 的患者 LDL 氧化水平显着增加。在本研究中，我们发现LCAT从氧化PC产生各种代谢物，并且LDL颗粒中的氧化PC分子作为底物。将氧化的1-棕榈酰-2-[1ィイD114ィエD1C]亚油酰PC与人血浆一起温育后，通过TLC分离中性脂质部分时，除了胆固醇酯之外，还形成了许多放射性条带。这些产品并非由天然 1-棕榈酰-2-[1-ィイD114ィエD1C] 亚油酰 PC 形成。来自 FLD 帕蒂的血浆也未能从氧化 PC 中形成附加产物。添加二硫代双（硝基苯甲酸酯）（DTNB）（一种 LCAT 抑制剂），或通过在 56°C 处理血浆 30 分钟来灭活 LCAT 活性，可以消除氧化 PC 中这些产物的生成。活性在高密度脂蛋白 (HDL) 组分中恢复，但在从正常血浆中分离的 LDL 组分中未恢复。当1-棕榈酰-2-[1-ィイD114ィエD1C]（9-氧壬酰）PC和1-硬脂酰-2-[1-ィイD114ィエD1C]（5-氧代戊酰）PC（含有短链醛的PC氧化产物）与人血浆一起孵育时，在TLC上观察到中性脂质部分中的放射性产物。使用抗载脂蛋白 B 抗体和 DLH3，通过夹心 ELISA 测量含有氧化 PC 的 LDL。发现重构的氧化 PC-LDL 颗粒在与 HDL 孵育后失去了结合 DLH3 的能力，而重构的氧化 PC-LDL 的反应性在 DTNB 存在下保持不变。这些结果表明，LCAT能够代谢PC的多种氧化产物，并防止循环LDL颗粒中氧化PC的积累。较少的

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