MOLECULAR BASIS OF OXIDATIVE MODIFICATION OF LDL

LDL 氧化修饰的分子基础

• 批准号: 6389390
• 负责人: LAWRENCE M SAYRE
• 金额: $ 30.99万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6389390
• 关键词: adduct; apolipoprotein B; atherosclerosis; autooxidation; chemical condensation; covalent bond; crosslink; cyclization; enzyme linked immunosorbent assay; epitope mapping; high performance liquid chromatography; human subject; immunochemistry; laboratory mouse; laboratory rabbit; low density lipoprotein; macrophage; peroxidation; proteolysis

Substantial evidence suggests that the accumulation and subsequent poor processing of oxidatively modified low density lipoprotein (oxLDL) by macrophages in the arterial wall contributes to the initial stages of atherogenesis. Oxidative modification of LDL involves the derivatization of its constituent apolipoprotein B and aminophospholipids by aldehydic breakdown products of lipid peroxidation, especially 4-hydroxy-2- nonenal (HNE). Many properties of oxLDL, such as development of lipofuscin-like fluorescence and the tendency toward aggregation, can be reproduced by direct treatment of LDL with HNE. The chemistry of HNE-protein adduction is highly complex, being heterogeneous, in part subject to reversible equilibria, and associated with time- and oxidation-dependent adduct "aging" and crosslinking reactions, a subset of which was elucidated during the past grant period. Our overall working hypothesis is that changes in the nature of lipoxidation-dependent adducts over time and following uptake of oxLDL into macrophages, are important determinants of foam cell formation. Moreover, since deficient intracellular processing may be tied more to one oxLDL scavenger receptor (e.g., CD36) than another, it is critically important to ascertain which oxLDL adducts most elicit recognition by this receptor. We have developed immunochemical tools to monitor the progression of adduct chemistry during in vitro oxidation and following intracellular accumulation in macrophage cells, relative to the end-stage adducts detected in atherosclerotic lesions obtained at surgery. The antibodies are also useful for monitoring the progression of lipoxidation-dependent changes on blood proteins in patients with cardiovascular and renal disease. The new work proposed, which continues to take advantage of the pooled multi-disciplinary expertise of three senior investigators at neighboring research institutions, furthers the development of novel structurally-specific analytical tools (immunochemical, mass spectroscopic, and isotopic) and their application to cell biological studies. The key feature of unambiguous structural determination is viewed as a crucial advantage for clarifying which modifications occurring in oxLDL are most associated with atherogenic properties and what environmental factors foster production of those toxic modifications. These studies will provide a basis for designing therapeutic countermeasures.

大量证据表明，动脉壁上巨噬细胞氧化修饰的低密度脂蛋白（oxLDL）的积累和随后的不良加工有助于动脉粥样硬化的初始阶段。LDL的氧化修饰包括脂质过氧化的醛解分解产物，特别是4-羟基-2-壬烯醛（HNE），使其组成的载脂蛋白B和氨基磷脂衍生化。oxLDL的许多特性，如脂褐素样荧光的发展和聚集倾向，可以通过HNE直接处理LDL来重现。hne -蛋白内合的化学反应是高度复杂的，是多相的，部分受可逆平衡的影响，并与时间和氧化依赖的加合物“老化”和交联反应有关，其中一部分在过去的资助期间得到了阐明。我们的总体工作假设是，随着时间的推移和巨噬细胞对oxLDL的摄取，脂氧化依赖加合物的性质发生了变化，这是泡沫细胞形成的重要决定因素。此外，由于细胞内加工缺陷可能更多地与一种oxLDL清道夫受体（如CD36）结合，因此确定哪种oxLDL加合物最能引起该受体的识别是至关重要的。我们开发了免疫化学工具来监测体外氧化过程中加合物化学的进展，以及巨噬细胞细胞内积聚，相对于在手术中获得的动脉粥样硬化病变中检测到的终末期加合物。该抗体还可用于监测心血管和肾脏疾病患者血液蛋白脂氧化依赖性变化的进展。新提出的工作继续利用邻近研究机构的三位高级研究员汇集的多学科专业知识，进一步发展新的结构特异性分析工具（免疫化学，质谱和同位素）及其在细胞生物学研究中的应用。明确的结构测定的关键特征被认为是澄清oxLDL中发生的哪些修饰与动脉粥样硬化特性最相关以及哪些环境因素促进了这些毒性修饰的产生的关键优势。这些研究将为设计治疗对策提供依据。