Project 2: Biochemical Pharmacology of Eicosapentaenoic Acid Oxidation

什么？- 3鱼油中存在的多不饱和脂肪酸（PUFA），特别是二十碳五烯酸（C20：5， ?- 3，EPA），用于预防和治疗许多疾病。这些机制 PUFA具有抗炎特性，但其保护作用尚不清楚。我们 一种假说是，3脂肪酸是由于，在某种程度上， 生物活性氧化产物和我们在过去两年中获得的数据支持这一假设。 以前，我们定义了自由基引发的花生四烯酸过氧化反应，并提出了一个 统一的氧化机制。主要的复杂过氧化产物由新化合物组成 含有单环和连环过氧化物和内过氧化物（异前列烷，IsoP）部分。这些 化合物具有有效的促炎生物活性， 流程.与花生四烯酸不同，3 PUFAs，特别是EPA，预计将 因为这些化合物含有额外的不饱和碳-碳键。 事实上，过去两年在这项赠款方面开展的工作表明情况确实如此。 在此更新申请中提出的研究将扩展我们关于生物化学的知识， EPA过氧化作用的药理学我们假设EPA的氧化可以被定义并导致 形成有助于PUFA抗炎特性的化合物。的结构和 提出的机制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PUFA在体内的主要生物相关形式，并提供了一个独特的机会来定义 以生理学相关形式的EPA的过氧化。此外，这将有助于开发 准确表征和定量复杂磷脂酰胆碱氧化产物的方法。一 对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，我们将从机理上定义EPA-PC的自由基引发的过氧化作用 并使用我们将开发的质谱方法来表征新的氧化产物。 在具体目标3中，我们将确定各种前体和抗氧化剂对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细胞因子的形成。 花生四烯酸衍生的IsoPs、白藜芦醇和白三烯。我们将 还检查了体内形成的EPA衍生的IsoPs的抗炎和血管活性特性。 我们认为，确定EPA的新氧化产物和研究这些氧化产物的机制， 化合物的形成将使人们深入了解EPA在人类生物学中的作用。

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.