MOLECULAR BASIS OF OXIDATIVE MODIFICATION OF LDL

大量证据表明，过度积累的氧化- 巨噬细胞修饰的低密度脂蛋白 壁有助于动脉粥样硬化斑块的发病机制。 LDL的氧化修饰涉及其衍生化， 通过脂质过氧化的分解产物的成分载脂蛋白B， 在很大程度上由反式-4-羟基-2-壬烯醛（HNE）引起。的许多性质 ox-LDL，如脂褐素样荧光的发展和 聚集倾向，可通过直接处理LDL 关于HNE HNE-蛋白加合的化学过程是高度复杂的， 不均匀的，部分受可逆平衡，和相关的 具有时间依赖性和自氧化依赖性加合物“老化”， 分子间交联势我们的总体工作假设是 HNE加合物结构中这种演变可以被识别 免疫化学上通过表位表达的变化，以及部分地通过 使用组特异性试剂和氚化HNE的生物化学研究 probes. 已经被巨噬细胞内化的Ox-LDL似乎 在HNE加合物结构中经历类似的转变，如存在于 人动脉粥样硬化病变的细胞外间隙。 拟议的工作反映了汇集的多学科专门知识， 附近研究机构的三名高级研究员 涉及模型中HNE加合化学的详细表征 仿生学研究，然后是抗体的开发， 识别HNE-LDL修饰的个别类型。 这些抗体 然后将用于免疫化学检测特定的HNE加合物， HNE-LDL。和ox-LDL在体外，对ox-LDL已内化， 培养的巨噬细胞和在手术中获得的动脉粥样硬化病变中。 HNE-LDL加合物出现的时空模式将是相关的 低密度脂蛋白修饰在积累方面的功能后果 在巨噬细胞中通过特异性受体摄取和对 其中的溶酶体降解。（一）明确的主要特点 加合物结构的测定和（ii）抗体特异性， 被视为澄清哪些修改的关键要求 氧化低密度脂蛋白中发生的与致动脉粥样硬化性质最相关， 这是HNE特有的。

Substantial evidence suggests that the over-accumulation of oxidatively- modified low density lipoprotein (ox-LDL) by macrophages in the arterial wall contributes to the pathogenesis of atherosclerotic.plaques. Oxidative modification of LDL involves the derivatization of its constituent apolipoprotein B by breakdown products of lipid peroxidation, to a large degree by trans-4-hydroxy-2-nonenal (HNE). Many properties of ox-LDL, 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-dependent and autoxidation-dependent adduct "aging" and intermolecular crosslinking potential. Our overall working hypothesis is that such evolution in HNE adduct structure can be identified immunochemically by changes in epitope expression and, in part, through biochemical studies using group-specific reagents and tritiated HNE probes. Ox-LDL which has been internalized by macrophages appears to undergo a similar shift in HNE adduct structure, as does ox-LDL present in the extracellular space of human atherosclerotic lesions. The work proposed, which reflects the pooled multi-disciplinary expertise of three senior investigators at neighboring research institutions, involves a detailed characterization of HNE adduction chemistry in model physiomimetic studies, followed by the development of antibodies which recognize individual types of HNE-LDL modifications. These antibodies will then be used for immunochemical detection of specific HNE adducts on HNE-LDL. arid ox-LDL in vitro, on ox-LDL which has been internalized in cultured macrophages, and in atherosclerotic lesions obtained at surgery. The spatiotemporal pattern of HNE-LDL adduct appearance will be correlated with functional consequences of LDL modification in terms of accumulation in macrophages via specific receptor uptake and susceptibility to lysosomal degradation therein. The key features of (i) unambiguous determination of adduct structure and (ii) antibody specificity, are viewed as crucial requirements for clarifying which modifications occurring in ox-LDL are most associated with atherogenic properties, and which are specific to HNE.