Differences in positional esterification of 14,15-epoxyelcosatrienoic acid in phosphatidylcholine of porcine coronary artery endothelial and smooth muscle cells
Differences in positional esterification of 14,15-epoxyelcosatrienoic acid in phosphatidylcholine of porcine coronary artery endothelial and smooth muscle cells
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DOI：
10.1016/s0090-6980(03)00002-9
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发表时间：
2003-04-01
影响因子：
2.9
通讯作者：
Spector, AA
中科院分区：
文献类型：
--
作者：
Fang, X;Weintraub, NL;Spector, AA
环氧二十碳三烯酸(EETs)很容易被结合到血管内皮细胞(EC)和平滑肌细胞(SMC)的磷脂中。将EETs掺入完整的猪冠状动脉可增强EC依赖的松弛，但不能增强仅作用于SMC的药物所引起的血管松弛。为了探讨这种差异的可能机制，用钙离子载体A23187处理预先负载了[H-3]14，15-EET的猪冠状动脉SMC和EC。虽然EET掺入EC和SMC的量相似，但A23187刺激EC释放的放射性增加了5倍，而SMC的释放仅增加了21%。细胞脂薄层层析(TLC)分析表明，在SMC和EC中，70%的结合放射性存在于磷脂酰胆碱(PC)中。用聚乳酸(2)处理EC PC后，TLC分析表明，75%的放射性以游离EET形式存在，25%的放射性以Lyso-PC形式存在。因此，在EC中，大部分14，15-EET被酯化成PC的sn-2位置。然而，在SMC中，在PLA2处理后，70%的放射性以lyso-PC的形式存在，这表明EET主要被酯化到sn-1位置。相反，在EC和SMC中，所有的14，15-EET都被酯化到PI的sn-2位。这些结果表明，14，15-EET优先掺入SMC中PC的sn-1位可能有助于解释化合物在SMC中的较大保留，而掺入EC中PC的sn-2位可能促进激动剂诱导的14，15-EET的释放和增强EC依赖的猪冠状动脉松弛。(C)2003 Elsevier Science Inc.保留所有权利。
Epoxyeicosatrienoic acids (EETs) are readily incorporated into phospholipids of smooth muscle cells (SMC) and endothelial cells (EC). Incorporation of EETs into intact porcine coronary arteries potentiates EC-dependent relaxation, but not vasorelaxation induced by agents that act solely on SMC. To explore the potential mechanisms responsible for this difference, porcine coronary artery SMC and EC preloaded with [H-3]14,15-EET were treated with calcium ionophore A23187. Although the amount of EET incorporated into EC and SMC was similar, A23187 stimulated a five-fold increase in release of radioactivity from EC, but only a 21% increase in release from SMC. Thin layer chromatography (TLC) examination of cell lipids demonstrated that >70% of the incorporated radioactivity was present in phosphatidylcholine (PC) in both SMC and EC. After treatment of EC PC with PLA(2), TLC analysis indicated that congruent to75% of radioactivity was present as free EET, and 25% of radioactivity was present as lyso-PC. Therefore, most of the 14,15-EET was esterified into the sn-2 position of PC in EC. However, in SMC, congruent to70% of radioactivity was present as lyso-PC after PLA2 treatment, indicating that the EET was predominately esterified into the sn-1 position. In contrast, all of the 14,15-EET was esterified into the sn-2 position of PI in both EC and SMC. These results suggest that the preferential incorporation of 14,15-EET into the sn-1 position of PC in SMC may help to explain the greater retention of the compound in SMC, while incorporation into the sn-2 position of PC in EC may facilitate agonist-induced 14,15-EET release and potentiation of EC-dependent porcine coronary artery relaxation. (C) 2003 Elsevier Science Inc. All rights reserved.