MOLECULAR BASIS OF OXIDATIVE MODIFICATION OF LDL

大量证据表明，动脉壁中的巨噬细胞对氧化修饰的低密度脂蛋白（oxLDL）的积累和随后的不良处理有助于动脉粥样硬化形成的初始阶段。 LDL的氧化修饰涉及其组分载脂蛋白B和氨基磷脂被脂质过氧化的降解产物，特别是4-羟基-2-壬烯醛（HNE）衍生化。 oxLDL的许多性质，如脂褐素样荧光的发展和聚集的趋势，可以通过直接处理LDL与HNE再现。 HNE-蛋白质加合的化学性质是高度复杂的，是异质的，部分地受到可逆平衡的影响，并且与时间和氧化依赖性加合物“老化”和交联反应相关，其中的一个子集在过去的授权期间被阐明。 我们的总体工作假设是，随着时间的推移和oxLDL进入巨噬细胞后，脂氧化依赖性加合物的性质发生变化，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（例如，CD 36），这是至关重要的，以确定氧化低密度脂蛋白加合物最引起这种受体的识别。 我们已经开发了免疫化学工具来监测加合物化学的进展，在体外氧化和巨噬细胞的细胞内积累，相对于在手术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的脂氧化依赖性变化的进展。这项新的工作继续利用邻近研究机构三位高级研究人员的多学科专业知识，进一步发展了新型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。 明确的结构确定的关键特征被认为是一个至关重要的优势，澄清发生在oxLDL的修饰是最相关的致动脉粥样硬化特性和环境因素促进生产这些有毒的修改。 这些研究将为设计治疗对策提供依据。

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.