Generation and metabolism of oxidized phospholipids which are active components in oxidized low density lipoprotein.

氧化低密度脂蛋白（OxLDL）被认为是动脉粥样硬化的关键因素。氧化磷脂酰胆碱（OxPC）在OxLDL中形成，是动脉粥样硬化的关键化合物，因为它们参与巨噬细胞的识别，并能够激活内皮细胞和其他血管细胞。我们利用抗OxPC单克隆抗体DLH3研究了OxPC-载脂蛋白ob复合物在泡沫细胞中的代谢命运以及OxPC在不同类型OxLDL制剂中的生成。同时用DLH3和抗载脂蛋白ob抗体对人动脉粥样硬化病变的泡沫细胞进行免疫组织化学染色，显示OxPC-apoB复合物的积累。仔细测量J774巨噬细胞中存在的OxPC-apoB复合物的数量，发现巨噬细胞吸收的一部分OxLDL在细胞中积累。当胞内细胞器在蔗糖上分离时，部分降解的OxLDL（小于100 kDa）在次级溶酶体中被回收。这些观察结果提供了oxldl相关抗原在动脉粥样硬化病变泡沫细胞中积累的代谢原理。近年来，在中等氧化条件下制备的最小修饰LDL （MM-LDL）被报道为生理OxLDL的良好模型。本文介绍了一种用1,4 -环己二酮处理后转化为荧光衍生物的方法，对含乙醛的游离OxPCs进行灵敏测定。用FeSO4在4℃下孵育LDL制备MM-LDL。虽然从TBARS值和琼脂糖凝胶上的电迁移率来看，MM-LDL的全颗粒修饰状态似乎非常温和，但MM-LDL中生成的游离和复杂形式的OxPC的数量要高于铜处理的OxLDL。当然，下一步需要测试MM-LDL制剂的生物学特性，但这一观察结果可能是阐明OxLDL中形成的OxPC对动脉粥样硬化的贡献的一个有趣的线索。少

Oxidized low density lipoprotein (OxLDL) is believed to be a cruicial factor for atherogenesis. Oxidized phosphatidylcholines (OxPC) formed in OxLDL should be key compounds for atherogenesis, since they are involved in recognition by macrophages and are capable of activating endothelial cells and other vascular cells. We investigated, by utilizing an anti-OxPC monoclonal antibody, DLH3, the metabolic fate of OxPC-apoB complex in foam cells and OxPC generation in various types of OxLDL preparations.Foam cells in human atherosclerotic lesions were simultaneously stained immunohistochemically with DLH3 and anti-apoB antibody, indicating accumulation of OxPC-apoB coomplex. Careful measurement of the amounts of OxPC-apoB coomplex present in J774 macrophages revealed that a part of OxLDL taken up by macrophages were accumulated in the cells. Partially degraded OxLDL (less than 100 kDa) were recovered in secondary lysosome fractions when intracellular organelles were fractionated on a sucrose … More density gradient. These observations provide a metabolic rationale why and how OxLDL-related antigens are accumulated in foam cells in atherosclerotic lesions.Recently, minimally modified LDL (MM-LDL), which is prepared by moderate oxidation contitions, is reported to be a good model for physiological OxLDL.We introduced a sensitve methos to measure free OxPCs containing aldehyde group by converting them to fluorescent derivertives after treatment with 1, 4-cyclohexanedione. MM-LDL was prepared by incubating LDL with FeSO4 at 4℃. Although modification status of whole particles for MM-LDL seemed to be very moderate judging by TBARS values and eleclromobility on agarose gel, the amounts of free and complex forms of OxPC generated in MM-LDL were rather higher than copper-treated OxLDL.It is certainly needed to test the biological properties of the MM-LDL preparations as the next step, but this observation might be a interesting clue to elucidate the contribution of OxPC formed in OxLDL for atherogenesis. Less