CHEMISTRY AND PHARMACOLOGY OF GLYCERYL PROSTAGLANDINS

环氧合酶-1和环氧合酶-2(COX-1和COX-2)催化花生四烯酸转化的关键步骤 酸转化为前列腺素(PGs)和血栓素A。COX-1在许多组织中有结构性表达， COX-2似乎在体内平衡功能中发挥作用，而COX-2受到高度调控，以响应一系列 激动剂，似乎有助于病理生理反应。选择性抑制COX-2的研究进展 用于开发降低胃肠道毒性的抗炎化合物。 然而，最近对与临床使用这些药物相关的心血管毒性的认识 提示COX-2在正常生理中的作用尚未得到充分认识。主要功能 COX-1和COX-2之间的差异主要归因于它们表达的差异。 然而，我们已经证明，COX-2能够氧化一系列花生四烯酸的中性衍生物。 酸，包括内源性大麻素，2-花生四烯基甘油(2-AG)。COX-2依赖的2-氨基酚的氧合作用 导致形成一系列PG甘油酯(PG-Gs)，其种类几乎与PG相同 他们自己。PG-G的形成发生在对炎症刺激有反应的巨噬细胞群中，并且 前列腺素E_2-G诱导RAW264.7细胞钙动员，支持PG-G代表 新一类脂类介体。在这里，我们建议进一步开发研究中心的资源，以 药理学和药物毒理学回答关于可能存在的关键问题 PG-Gs在体内的生理作用。我们将1)应用脂质组学和RNAi技术来监测总脂质 巨噬细胞在PG-G合成过程中的变化，以确定导致2-AG和 调节2-氨基糖形成的特定酶。2)对相互作用进行详细的动力学研究 过氧化氢甘油酯与环氧合酶-2联合检测环氧合酶-2直接产物PGG2-G 2-AG的氧合作用，与PGG2的激活或失活能力不同；3)PGG的特性 兔肾髓质间质细胞的形成，这似乎是一个潜在的来源 在高渗条件下可能对调节肾功能起重要作用的PG-Gs的数量；4) 研究前列腺素E_2-G在猴子体内的代谢特征，以确定PG-G的独特代谢物 用于量化这些化合物在人体内的生物合成。这些实验将提供关键的 信息有助于更好地了解PG-Gs在体内的作用，并将有助于测试 PG-G合成代表COX-2独特生理功能的假说。

Cyclooxygenases-1 and -2 (COX-1 and COX-2) catalyze the committed step in the conversion of arachidonic acid to prostaglandins (PGs) and thromboxane. COX-1 is constitutively expressed in many tissues and appears to play a role in homeostatic functions whereas COX-2 is highly regulated in response to a range of agonists and appears to contribute to pathophysiological responses. Selective inhibition of COX-2 has been exploited for the development of anti-inflammatory compounds with reduced gastrointestinal toxicities. However, the recent recognition of cardiovascular toxicity associated with the clinical use of these agents suggests that the role of COX-2 in normal physiology has not been fully appreciated. The major functional differences between COX-1 and COX-2 have primarily been attributed to their differential expression. However, we have shown that COX-2 is able to oxygenate a range of neutral derivatives of arachidonic acids, including the endocannabinoid, 2-arachidonylglycerol (2-AG). COX-2-dependent oxygenation of 2-AG leads to the formation of a range of glyceryl esters of PGs (PG-Gs) that is nearly as diverse as the PGs themselves. PG-G formation occurs in macrophage populations responding to inflammatory stimuli, and PGE2-G induces Ca2+ mobilization in RAW264.7 cells, supporting the hypothesis that PG-Gs represent a new class of lipid mediators. Here we propose to further exploit the resources of the Research Center for Pharmacology and Drug Toxicology to answer key remaining questions concerning the possible physiological roles of PG-Gs in vivo. We will 1) apply lipidomics and RNAi technology to monitor total lipid changes in macrophages during PG-G synthesis in order to identify the lipid pools that give rise to 2-AG and the specific enzymes that regulate 2-AG formation. 2) perform detailed kinetic studies of the interaction of hydroperoxy glyceryl esters with COX-2 in order to determine if PGG2-G, the immediate product of COX-2 oxygenation of 2-AG, differs from PGG2 in its ability to activate or inactivate the enzyme; 3) characterize PGG formation by rabbit renal medullary interstitial cells, which appear to be a potential source of large quantities of PG-Gs that may be important in the regulation of renal function under hypertonic conditions; 4) characterize PGE2-G metabolism in the monkey in vivo to identify unique metabolites of PG-Gs that can be used to quantify in vivo biosynthesis of these compounds in humans. These experiments will provide critical information toward the development of a better understanding of the role of PG-Gs in vivo, and will help test the hypothesis that PG-G synthesis represents a unique physiologic function of COX-2.