ENDOTHELIAL ACTIVATION BY AN ISOPROSTANE PHOSPHOLIPID

异前列腺素磷脂对内皮细胞的激活

• 批准号: 6537780
• 负责人: Judith Anne Berliner
• 金额: $ 22.95万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6537780
• 关键词: cell adhesion; epoxides; lipid structure; phospholipids; protein binding; receptor binding; vascular endothelium

The overall goal of this proposal is to synthesize and use for biologic studies a novel bioactive epoxy isoprostane phospholipid that may play an important role the development of atherosclerotic lesions. 1-Palmitoyl-2- (5,6-epoxyisoprostane E2)-sn-glycero-3-phosphocholine (PEIPC), mass 828.5, is present in minimally oxidized LDL (MM-LDL) and increased in atherosclerotic lesions. PEIPC is one of five 828.5 isomers in MM-LDL and in preliminary studies causes a strong activation (compared to the other relatively inactive isomers) of endothelial cell to bind monocytes in vitro. The proposed studies will test the hypothesis that PEIPC activates endothelial cells by interacting with a PAF-like receptor and will characterize binding to this receptor. Most of our preliminary studies of molecules of this mass have been done with mixed isomers. Isomers of 828.5 were shown to highly accumulate in HDL (compared to other bioactive phospholipids) probably because HDL enzymes less easily degrade isomers of 828.5 than other bioactive phospholipids. In preliminary studies we have demonstrated that HDL, shown by others to be less protective against endothelial activation, contained increased levels of 828.5. HDL has been shown to bind at least one of the scavenger receptors. Studies by the Witztum group have shown that l-Palmitoyl-2- (oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC), another bioactive phospholipid with antigenic similarity to PEIPC, also binds to macrophage scavenger receptors. We will test the hypothesis that, in endothelial cells, PEIPC binds to the major scavenger receptor LOX-l blocking its normal interaction with HDL. Finally there is evidence that some oxidized phospholipids may bind to proteins and interact with cells in this adducted form. The structure of PEIPC suggests that it may bind to proteins under physiological or pathophysiological conditions. Such adducted phospholipids may be more stable than free bioactive phospholipids. We will test the hypothesis that PEIPC forms adduct with proteins and peptides; and we will perform limited studies using these adducts. Key to carrying out these studies is the availability of a reliable supply of PEIPC and the ability to obtain radiolabeled molecules. This proposal is a combined submission from a chemist with extensive experience in the synthesis of epoxide containing molecules, a cell biologist experienced with testing lipid endothelial interactions and a coinvestigator experienced in both areas. In summary, this interdisciplinary proposal will provide important information about the receptor interactions of the novel epoxy isoprostane phospholipid PEIPC.

该提案的总体目标是合成一种新型生物活性环氧异前列烷磷脂并用于生物学研究，该磷脂可能在动脉粥样硬化病变的发展中发挥重要作用。 1-棕榈酰-2-（5,6-环氧异前列烷 E2）-sn-甘油-3-磷酸胆碱 (PEIPC)，质量为 828.5，存在于最低限度氧化的低密度脂蛋白 (MM-LDL) 中，并在动脉粥样硬化病变中增加。 PEIPC 是 MM-LDL 中的五种 828.5 异构体之一，初步研究表明，它会导致内皮细胞强烈激活（与其他相对不活跃的异构体相比），从而在体外结合单核细胞。拟议的研究将测试 PEIPC 通过与 PAF 样受体相互作用来激活内皮细胞的假设，并将表征与该受体的结合。我们对这种质量的分子的大部分初步研究都是使用混合异构体进行的。 828.5 的异构体被证明在 HDL 中高度积累（与其他生物活性磷脂相比），可能是因为 HDL 酶比其他生物活性磷脂更不易降解 828.5 的异构体。在初步研究中，我们已经证明 HDL 的 828.5 水平有所增加，而其他研究表明 HDL 对内皮激活的保护作用较小。 HDL 已被证明可以结合至少一种清道夫受体。 Witztum 小组的研究表明，l-棕榈酰-2-（氧代戊酰）-sn-甘油-3-磷酸胆碱 (POVPC) 是另一种与 PEIPC 具有抗原相似性的生物活性磷脂，也能与巨噬细胞清道夫受体结合。我们将测试以下假设：在内皮细胞中，PEIPC 与主要清道夫受体 LOX-1 结合，阻断其与 HDL 的正常相互作用。最后有证据表明，一些氧化磷脂可能与蛋白质结合，并以这种加合形式与细胞相互作用。 PEIPC 的结构表明它可以在生理或病理生理条件下与蛋白质结合。这种加合磷脂可能比游离生物活性磷脂更稳定。我们将检验 PEIPC 与蛋白质和肽形成加合物的假设；我们将使用这些加合物进行有限的研究。开展这些研究的关键是能否获得可靠的 PEIPC 供应以及获得放射性标记分子的能力。该提案是由一位在含环氧化物分子合成方面拥有丰富经验的化学家、一位在测试脂质内皮相互作用方面经验丰富的细胞生物学家以及一位在这两个领域都有丰富经验的共同研究人员共同提交的。总之，这一跨学科提案将提供有关新型环氧异前列烷磷脂 PEIPC 受体相互作用的重要信息。