CHEMISTRY AND PHARMACOLOGY OF GLYCERYL PROSTAGLANDINS

甘油基前列腺素的化学和药理学

• 批准号: 7209624
• 负责人: LAWRENCE J. MARNETT
• 金额: $ 15.96万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7209624
• 关键词: RNA interference; eicosanoid metabolism; eicosanoids; fatty acid biosynthesis; glycerol; inflammation; macrophage; pharmacokinetics; pharmacology; prostaglandin endoperoxide synthase; prostaglandins; toxicology

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.

环加氧酶-1和环加氧酶-2（考克斯-1和考克斯-2）催化花生四烯酸转化中的关键步骤， 酸对前列腺素（PGs）和血栓素的影响。考克斯-1在许多组织中组成性表达， COX-2似乎在体内平衡功能中起作用，而考克斯-2在响应一系列 激动剂，似乎有助于病理生理反应。选择性抑制考克斯-2已经被证明是一种有效的方法。 用于开发具有降低的胃肠道毒性的抗炎化合物。 然而，最近认识到心血管毒性与这些药物的临床使用 提示考克斯-2在正常生理学中的作用还没有被充分认识。三位主要机能 考克斯-1和考克斯-2之间的差异主要归因于它们的差异表达。 然而，我们已经表明，考克斯-2能够使花生四烯酸的一系列中性衍生物， 酸，包括内源性大麻素，2-花生四烯酸甘油（2-AG）。2-AG的考克斯-2依赖性氧合 导致形成一系列PGs的甘油酯（PG-Gs），其几乎与PGs一样多样 自己PG-G形成发生在对炎症刺激作出反应的巨噬细胞群中， PGE 2-G可诱导RAW264.7细胞内Ca 2+的流动，支持PG-Gs代表细胞内Ca 2+浓度的假说。 新一类脂质介质。在这里，我们建议进一步利用研究中心的资源， 药理学和药物毒理学，以回答有关可能的 PG-Gs在体内的生理作用。我们将1）应用脂质组学和RNAi技术监测总脂质 PG-G合成过程中巨噬细胞的变化，以鉴定产生2-AG的脂质池， 调节2-AG形成的特定酶。2)进行详细的动力学研究， 用考克斯-2的过氧化氢甘油酯，以确定PGG 2-G，考克斯-2的直接产物 2-AG的氧合，不同于PGG 2，在于其激活或抑制酶的能力; 3）表征PGG 形成的兔肾髓质间质细胞，这似乎是一个潜在的来源， 在高渗条件下可能对肾功能调节重要的PG-Gs的量; 4） 表征猴体内的PGE 2-G代谢，以鉴定可用于治疗的PG-G的独特代谢物。 用于定量这些化合物在人体内的体内生物合成。这些实验将提供关键的 信息的发展，更好地了解PG-Gs在体内的作用，并将有助于测试 PG-G合成代表考克斯-2独特生理功能的假设。