HUMAN PHARMACOLOGY OF DOCOSAHEXAENOIC ACID OXIDATION

大量证据表明，omega-3多不饱和脂肪酸（PUFA）的摄入量增加， 特别是二十二碳六烯酸（DHA）在预防人类疾病如动脉粥样硬化中的用途。 DHA的保护机制尚不清楚，尽管研究表明， DHA的氧化产物具有抗炎作用。然而，这些化合物尚未被鉴定。 在上一轮的资助中，我们定义了自由基引发的胆固醇过氧化反应， 花生四烯酸在动脉粥样硬化的背景下，并提出了一个统一的机制，其氧化。 主要的过氧化产物是含有单环和连环过氧化物的新型化合物 和内过氧化物（异前列烷，IsoP）部分。这些化合物具有强效的促炎作用， 生物活性和可能介导各种生理和病理生理过程。与花生四烯酸不同， DHA的氧化被预测为明显更复杂，因为它含有两个额外的碳碳 不饱和键拟议的研究将检查DHA过氧化作用的人体药理学 在动脉粥样硬化的背景下。我们假设DHA的氧化可以被定义，并导致 形成有助于这种PUFA的抗炎特性的化合物。的结构和 机械工作将使用二十二碳六烯酰甘油磷脂酰乙醇胺（DHA-PE），因为它是一种 主要的生物学相关形式，并提供了一个独特的机会，以确定氧化的DHA， 生理相关的背景。此外，这将有助于制定方法， 表征复合磷脂氧化产物。详细研究了DHA的过氧化作用， 这件事的任何PUFA，甘油磷脂中的补充还没有进行。 在具体目标1和2中，我们将从机理上定义自由基引发的 使用新型色谱和质谱方法的DHA-PE。 在具体目标3中，我们将确定各种因素的影响，包括我们所研究的新型抗氧化剂。 已经开发，在体外和体内形成不同的DHA-PE过氧化产物。 在具体目标4中，我们将研究DHA的炎症介导特性，并选择 过氧化产物我们将研究DHA在多大程度上减少促炎因子的形成， 类花生酸在动物和人类中的作用，以及在小鼠模型中减少动脉粥样硬化的程度。 最后，我们将研究一种高活性DHA衍生的 在体内大量形成的含环戊烯酮的IsoP样化合物，4-A4 t-神经前列腺素。 我们认为，鉴定DHA-PE的新氧化产物和检查 这些化合物在体内形成的机制将使我们深入了解这种PUFA在以下方面的作用： 人类生理学和病理生理学。

Significant evidence implicates increased consumption of omega-3 polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA), in the prevention of human diseases such as atherosclerosis. The mechanism by which DHA is protective is unknown although studies suggest that non-enzymatic oxidation products of DHA are anti-inflammatory. Nonetheless, these compounds have not been identified. In the previous cycle of this grant, we defined the free radical-initiated peroxidation of cholesteryl arachidonate in the context of atherosclerosis and have proposed a unified mechanism for its oxidation. The major peroxidation products consist of novel compounds containing mono- and serial cyclic peroxide and endoperoxide (isoprostane, IsoP) moieties. These compounds possess potent pro-inflammatory bioactivity and likely mediate various physiological and pathophysiological processes. Unlike arachidonate, the oxidation of DHA is predicted to be significantly more complex since it contains two additional carboncarbon unsaturated bonds. Studies proposed will examine the human pharmacology of DHA peroxidation in the context of atherosclerosis. We hypothesize the oxidation of DHA can be defined and results in the formation of compounds that contribute to the anti-inflammatory properties of this PUFA. The structural and mechanistic work will use docosahexaenoyl-glycerophosphatidylethanolamine (DHA-PE), because it is a major biologically relevant form and offers a unique opportunity to define the peroxidation of DHA in a physiologically relevant context. In addition, this will allow for the development of approaches to accurately characterize complex phospholipid oxidation products. A detailed study of the peroxidation of DHA, or for that matter any PUFA, esterifed in glycerophospholipids has not been undertaken. In Specific Aims 1 and 2, we will define mechanistically the free radical-initiated peroxidation of DHA-PE using novel chromatographic and mass spectrometric approaches. In Specific Aim 3, we will determine the effect of various factors, including novel antioxidants that we have developed, on the formation of different DHA-PE peroxidation products in vitro and in vivo. In Specific Aim 4, we will examine the inflammatory-mediating properties of DHA and selected peroxidation products. We will study the extent to which DHA decreases the formation of pro-inflammatory eicosanoids in animals and humans and also to what degree it reduces atherosclerosis in mouse models. Finally, we will examine the anti-inflammatory properties of one highly reactive DHA-derived cyclopentenone-containing IsoP-like compound formed in abundance in vivo, 4-A4t-neuroprostane. We contend that studies identifying novel oxidation products of DHA-PE and examining mechanisms by which these compounds are formed in vivo will yield insights into the role of this PUFA in human physiology and pathophysiology.