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）参与血浆氧化磷脂酰胆碱（PC）代谢的可能性。低密度脂蛋白（LDL）氧化后，PC形成多种氧化产物。在家族性LCAT缺乏症（FLD）患者中LDL氧化水平的显著增加先前已通过使用识别PC氧化产物的单克隆抗体DLH 3对氧化LDL进行灵敏的夹心ELISA证明。在本研究中，我们发现LCAT从氧化PC产生各种代谢产物，LDL颗粒中的氧化PC分子作为底物。将氧化的1-棕榈酰-2-[1 $>イD114 D1 C]亚油酰PC与人血浆孵育后，通过TLC分离中性脂质部分时，除胆固醇酯外，还形成了许多放射性条带。这些产物不是由天然1-棕榈酰-2-[1-棕榈酰D114-棕榈酰D1C]亚油酰PC形成的。FLD患者血浆 ...更多信息 nts也不能从氧化的PC形成另外的产物。加入二硫代-双（硝基苯甲酸酯）（DTNB），一种LCAT抑制剂，或通过在56 ℃下处理血浆30分钟使LCAT活性失活，消除了氧化PC产生这些产物。在高密度脂蛋白（HDL）组分中恢复活性，但在从正常血浆中分离的LDL组分中未恢复活性。当1-棕榈酰-2-[1-异戊酰D114异戊酰D1C]（9-氧代壬酰）PC和1-硬脂酰-2-[1-异戊酰D114异戊酰D1C]（5-氧代戊酰）PC（含有短链醛的PC氧化产物）与人血浆孵育时，在TLC上观察到中性脂质组分中的放射性产物。用抗载脂蛋白B抗体和DLH 3夹心ELISA法测定了氧化PC-LDL的含量。发现氧化PC-LDL与HDL孵育后失去了与DLH 3的结合能力，而与DTN B孵育后氧化PC-LDL的反应性保持不变。这些结果表明，LCAT能够代谢PC的各种氧化产物，并防止氧化PC在循环LDL颗粒中的积累。少

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