Oxidation of Apolipoprotein B-100 in LDL

描述（由申请人提供）：有大量证据 表明低密度脂蛋白（LDL）的氧化修饰 显著有助于启动和/或进展 动脉粥样硬化尽管许多关于LDL脂质氧化的研究 虽然已经发表，但对氧化修饰的了解要少得多。 脱辅基蛋白载脂蛋白的化学多样性大于LDL 脂质提供了更大的生物标志物特异性的机会， 特殊氧化机制的独特贡献。第一 本提案的具体目的是检验氧化 LDL体外氧化的候选机制 在体内产生脱辅基蛋白（apo B-100）的修饰， 足够可区分，可用作LDL氧化的生物标志物 在体内通过各自的机制。在迄今为止的研究中，我们观察到 在LDL氧化中形成的apoB-100氧化产物的明显差异 在体外通过Cu 2+、HOCl和髓过氧化物酶（MPO）。我们建议调查 类似地，通过Fe 2+催化的氧化、硝化、还原和还原， (NO和ONOO供体，MPO或嗜酸性粒细胞过氧化物酶约PO]+ NO2-），和 由培养的细胞介导的氧化，包括内皮细胞、血管内皮细胞、 平滑肌细胞和单核细胞。这些研究将采用隔离方法 基于高效液相色谱法（HPLC）和结构 基于质谱的表征方法。第二个具体目标 这项建议是为了检验循环LDL的亚组分 从某些个体分离的基因组DNA将表现出特异性修饰apoB-100 氧化，这将反映有限的子集的氧化产物， LDL在体外的特征在于具体目标1。第三个具体目标 一项提议是检验从动脉粥样硬化物质中分离的LDL 将显示出有限的载脂蛋白氧化产物子集， 具体目标是i。我们迄今为止的结果提供了非常强大的 支持我们基于此应用程序的工作假设。的 提出的研究目标是开发一种区分 LDL氧化的特定机制，被怀疑有助于 LDL在体内的氧化和动脉粥样硬化形成。长期目标是 研究是为了创造更具体的治疗机制的基础， 努力延缓动脉粥样硬化的发生和发展， 开发这些不同氧化机制的生物标志物， 这些治疗措施的效果。最后，我们提出的研究 不限于与动脉粥样硬化或甚至与LDL氧化的相关性， 但这些研究中提出的概念和方法很容易应用， 与多种重要的人类疾病有关， 建议进程作出贡献。

DESCRIPTION (provided by the applicant): There is a large body of evidence suggesting that oxidative modifications of low-density lipoproteins (LDL) contribute significantly to the initiation and/or progression of atherosclerosis. Although numerous studies of the oxidation of LDL lipids have been published, far less is known about the oxidative modification of the apoprotein. The greater chemical diversity of the apoprotein than of the LDL lipids offers the opportunity for greater biomarker specificity for distinguishing contributions of specific mechanisms of oxidation. The first Specific Aim of the present proposal is to test the hypothesis that oxidations of LDL in vitro by methods that are candidate mechanisms for oxidation of LDL in vivo produce modifications of the apoprotein (apo B-100) that are sufficiently distinguishable to be empIoyed as biomarkers for oxidation of LDL in vivo by the respective mechanisms. In our studies to date we have observed clear differences in products of apoB-1 00 oxidation formed in oxidation of LDL in vitro by Cu2+, HOCl, and myeloperoxidase (MPO). We propose to investigate similarly the oxidation of LDL in vitro by Fe2+-catalyzed oxidation, nitration (NO and ONOOdonors, MPO or eosinophil peroxidase aboutPO] plus NO2-), and oxidation mediated by cultured cells, including endothelial cells, vascular smooth muscle cells and monocytes. These studies will employ isolation methods based on high performance liquid chromatography (HPLC) and structural characterization methods based on mass spectrometry. The second Specific Aim of this proposal is to test the hypothesis that subfractions of circulating LDL isolated from some individuals will exhibit specific modifications apoB-1 00 oxidation that will reflect a limited subset of the products of oxidation of LDL in vitro characterized in Specific Aim 1. The third Specific Aim of this proposal is to test the hypothesis that LDL isolated from atheromatous material will exhibit a limited subset of the products of apoprotein oxidation that were characterized in Specific Aim i. Our results to date provide very strong support for the working hypotheses upon which we base this application. The goal of the studies proposed is to develop a means of distinguishing the specific mechanisms of LDL oxidation that are suspected to contribute to the oxidation of LDL in vivo and to atherogenesis. The longer-term goals of this research are to create the basis for more mechanistically specific therapeutic efforts to retard the initiation and progression of atherosclerosis and to develop biomarkers of these distinct mechanisms of oxidation to monitor efficacies of these therapeutic interventions. Finally, the studies we propose are not limited in relevance to atherosclerosis or even to oxidation of LDL, but the concepts and methods developed in these studies are readily applicable to a wide range of important human diseases for which unspecified oxidative processes are proposed to contribute.