Project 2: Biochemical Pharmacology of Eicosapentaenoic Acid Oxidation

-3多不饱和脂肪酸(PUFA)存在于鱼油中，特别是二十碳五烯酸(C20：5， ？-3，EPA)，用于预防和治疗许多疾病。它们所依据的机制 多不饱和脂肪酸具有保护性，尽管它们具有抗炎特性，但目前尚不清楚。我们的 假说认为？-3脂肪酸的抗炎作用部分归因于 我们在过去两年中产生的生物活性氧化产物和数据支持这一假设。 此前，我们定义了自由基引发的花生四烯酸过氧化反应，并提出了一种 其氧化的统一机理。主要的复合过氧化产物由新型化合物组成。 含有单环和系列环过氧化氢和内过氧物(异前列腺素，IsoP)部分。这些 化合物具有很强的促炎生物活性，可能介导多种病理生理过程 流程。与花生四烯酸不同，β-3多不饱和脂肪酸，特别是epa的氧化被预测为 要复杂得多，因为这些化合物含有额外的不饱和碳-碳键。 过去两年在这笔赠款中开展的工作确实证明了这一点。 在这次续签申请中提出的研究将扩展我们关于生物化学和 EPA过氧化的药理学。我们假设EPA的氧化可以被定义并导致 形成有助于多不饱和脂肪酸抗炎性能的化合物。结构和 提出的机理工作将使用二十碳五烯酰甘油磷脂酰胆碱(EPA-PC)，因为它是一种 这种多不饱和脂肪酸在体内的主要生物学相关形式，并提供了一个独特的机会来定义 EPA在生理上相关的过氧化作用。此外，这将允许开发 准确表征和定量复杂磷脂酰胆碱氧化产物的方法。一个 在磷脂酰胆碱中酯化的EPA的过氧化作用还没有进行详细的研究。， 在具体目标1和2中，我们将从机制上定义EPA-PC的自由基引发的过氧化 并使用我们将开发的质谱学方法来表征新的氧化产物。 在具体目标3中，我们将确定各种促进剂和抗氧化剂对EPA-PC形成的影响 过氧化产物。 在具体目标4中，我们将确定EPA抗炎特性的机制 及其过氧化产物。我们将研究EPA在多大程度上减少促炎性物质的形成 人和动物中花生四烯酸衍生的同工酶、前列腺素和白三烯。我们会 还要检查EPA衍生的体内形成的IsoP的抗炎和血管活性特性。 我们认为，识别EPA的新氧化产物并研究这些氧化产物的机制 化合物的形成将使人们对EPA在人类生物学中的作用有更深入的了解。

The ?-3 polyunsaturated fatty acids (PUFAs) present in fish oil, particularly eicosapentaenoic acid (C20:5, ?-3, EPA), are used in the prevention and treatment of many diseases. The mechanisms by which these PUFAs are protective are not understood although they possess anti-inflammatory properties. Our hypothesis is that the anti-inflammatory effects of ?-3 fatty acids are due, in part, to the generation of bioactive oxidation products and data we have generated in the past two years support this hypothesis. Previously, we defined the free radical-initiated peroxidation of arachidonic acid and have proposed a unified mechanism for its oxidation. The major complex 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 pathophysiological processes. Unlike arachidonate, the oxidation of ?-3 PUFAs, and in particular EPA, is predicted to be significantly more complex since these compounds contain additional unsaturated carbon-carbon bonds. Work carried out in this grant over the past two years has, indeed, shown this to be the case. Studies proposed in this renewal application will extend our knowledge regarding the biochemistry and pharmacology of EPA peroxidation. We hypothesize the oxidation of EPA can be defined and results in the formation of compounds that contribute to the anti-inflammatory properties of the PUFA. The structural and mechanistic work proposed will use eicosapentaenoyl-glycerophosphatidylcholine (EPA-PC), because it is a major biologically relevant form of this PUFA in vivo and offers a unique opportunity to define the peroxidation of EPA in a physiologically relevant form. In addition, this will allow for the development of approaches to accurately characterize and quantify complex phosphatidylcholine oxidation products. A detailed study of the peroxidation of EPA esterified in phosphatidylcholine has not been undertaken. , In Specific Aims 1 and 2, we will define mechanistically the free radical-initiated peroxidation of EPA-PC and characterize novel oxidation products using mass spectrometric approaches that we will develop. In Specific Aim 3, we will determine the effect of various pro- and antioxidants on the formation of EPA-PC peroxidation products. In Specific Aim 4, we will determine mechanisms that account for the anti-inflammatory properties of EPA and its peroxidation products. We will study the extent to which EPA decreases the formation of proinflammatory arachidonate-derived IsoPs, prostaglandins and leukotrienes in humans and animals. We will also examine the anti-inflammatory and vasoactive properties of EPA-derived IsoPs that are formed in vivo. We believe that identifying novel oxidation products of EPA and examining mechanisms by which these compounds are formed will yield insights into the role of EPA in human biology.