Novel Pathways of Eicosanoid Metabolism

前列腺素和其他类二十烷化合物是由环加氧酶、脂加氧酶和细胞色素P450氧化花生四烯酸而产生的。二十烷酸作为重要的脂质类自身激素（局部激素），信号传导和调节炎症、发热、疼痛和其他生理和病理生理过程。前列腺素和其他类二十烷类在体内的短暂性，在大多数情况下阻碍了它们在形成部位的直接定量测量。相反，尿液代谢物已被确立为生理和病理生理事件中类二十烷醇形成的方便、可靠和非侵入性标记物。同样，这些标记物也用于评估抗炎药物和其他用于调节其生物合成的药物的效果和功效。在这里，我们将验证前列腺素D2 （PGD2）在形成异常高的量时，部分代谢为11-脱氢血栓素B2 （11d-TxB2）的假设。这一假设是基于对已发表数据和初步研究的重新解释，这些研究表明PGD2、PGD- M和11d-TxB2的尿代谢产物平行形成，并在小鼠中将标记的PGD2代谢为标记的11d-TxB2。假设同样的代谢途径也参与了其他二十烷类物质的代谢，包括PGE2和15-deoxy-∆- pgj2。我们将在三个具体目标中检验这一假设。在12,14目的1中，我们将分析尿代谢产物PGD-M， 11d-TxB2和2,3-dino - txb2在PGD2形成增加的人类模型中的形成时间过程。在具体目标2中，我们将使用药理学和遗传学小鼠模型来提供PGD2向11d-TxB2转化的机制分析。在具体目标3中，我们将使用重组酶和肝组织组分来确定参与新代谢途径的酶。总之，这些研究将导致重新评估尿液代谢物对其母体前列腺素和类二十烷酸的定量分析的效用。这些标志物在抗血小板治疗评估中的有效性具有直接的临床和翻译相关性。

Prostaglandins and other eicosanoids are derived from cyclooxygenase, lipoxygenase, and cytochrome P450 oxygenation of arachidonic acid. Eicosanoids serve as important lipid autacoids (local hormones) to signal and regulate inflammation, fever, pain, and other physiological and pathophysiological processes. The fleeting nature of prostaglandins and other eicosanoids in vivo precludes in most cases their direct quantitative measurement at the sites of their formation. Instead, urinary metabolites have been established as convenient, reliable, and non-invasive markers for the formation of eicosanoids during physiological and pathophysiological events. Likewise, these markers are used to assess the effects and efficacy of anti-inflammatory drugs and other medications used to modulate their biosynthesis. Here, we will test the hypothesis that prostaglandin D2 (PGD2), when formed in unusually high amounts, is metabolized in part to 11- dehydro-thromboxane B2 (11d-TxB2). This hypothesis is based on re-interpretation of published data and preliminary studies that show parallel formation of a urinary metabolite of PGD2, PGD- M, and 11d-TxB2, and metabolism of labeled PGD2 to labeled 11d-TxB2 in mice. The same metabolic pathway is hypothesized to be involved in the metabolism of other eicosanoids, including PGE2 and 15-deoxy-∆ -PGJ2. We will test the hypothesis in three specific aims. In 12,14 aim 1 we will analyze the time course of formation of the urinary metabolites PGD-M, 11d-TxB2, and 2,3-dinor-TxB2 in human models of increased formation of PGD2. In specific aim 2 we will use pharmacologic and genetic mouse models to provide a mechanistic analysis of the transformation of PGD2 to 11d-TxB2. In specific aim 3 we will use recombinant enzymes and liver tissue fractions to identify the enzyme(s) involved in the novel metabolic pathway. Together, these studies will lead to a re-evaluation of the utility of urinary metabolites for the quantitative analysis of their parent prostaglandins and eicosanoids. There is immediate clinical and translational relevance for the usefulness of these markers in the assessment of anti-platelet therapy.