Tokumura A, Moriyama T, Minamino H, Hayakawa T, Tsukatani H
Faculty of Pharmaceutical Sciences, University of Tokushima, Japan.
Biochim Biophys Acta. 1997 Jan 7;1344(1):87-102. doi: 10.1016/s0005-2760(96)00130-0.
Treatment of suspensions of guinea pig peritoneal polymorphonuclear leukocytes (PMN) with four species of phosphatidate (PA) containing short-chain fatty acids induced sustained superoxide anion (O2-) production after a lag time. The rank order of efficiency of these PAs in triggering O2- production was PA8:0 [1,2-dioctanoyl-sn-glycerol-3-phosphate (GP)] > PA10:0 (1,2-didecanoyl-GP) > PA6:0 (1,2-dicaproyl-GP) > > PA12:0 (1,2-dilauroyl-GP). The O2- release from PMN stimulated with PA10:0 or PA12:0, but not with PA6:0 or PA8:0, was lowered by the addition of 1 mM extracellular Ca2+. Studies with various inhibitors showed that the mechanism of multiphasic O2- production induced by PA8:0 depended on its concentration: 1 and 3 microM PA8:0 induced O2- production constantly after a lag time through a protein kinase-dependent mechanism that was inhibited by 100 nM staurosporine. With concentrations of PA of 10 microM or more, an additional mechanism that was independent of protein kinase became operative and predominant over the protein kinase-dependent one. This protein kinase-independent mechanism was inhibited selectively by 80 microM TMB-8. Concentrations of 30, 60 and 100 microM PA first elicited transient O2- production via another protein kinase-dependent mechanism that was more sensitive to H-7 than to staurosporine, and then sustained O2- production, mainly driven by the protein kinase-independent mechanism. Metabolism of exogenously added [14C]PA8:0 in intact PMN was examined in the presence and absence of propranolol. Results suggest that PA itself is more important rather than its degradation products such as diacylglycerol, in inducing O2- production via three different mechanisms described above.
用四种含有短链脂肪酸的磷脂酸（PA）处理豚鼠腹膜多形核白细胞（PMN）悬浮液，经过一段延迟时间后会诱导超氧阴离子（O₂⁻）持续产生。这些PA触发O₂⁻产生的效率排序为：PA8:0 [1,2 - 二辛酰 - sn - 甘油 - 3 - 磷酸（GP）] > PA10:0（1,2 - 二癸酰 - GP）> PA6:0（1,2 - 二己酰 - GP）>> PA12:0（1,2 - 二月桂酰 - GP）。添加1 mM细胞外Ca²⁺可降低PA10:0或PA12:0刺激PMN释放的O₂⁻，但PA6:0或PA8:0刺激的则不受影响。用各种抑制剂进行的研究表明，PA8:0诱导多相O₂⁻产生的机制取决于其浓度：1和3 μM的PA8:0经过一段延迟时间后通过蛋白激酶依赖性机制持续诱导O₂⁻产生，该机制可被100 nM的星形孢菌素抑制。当PA浓度为10 μM或更高时，一种独立于蛋白激酶的额外机制开始起作用并占主导地位。这种独立于蛋白激酶的机制可被80 μM的TMB - 8选择性抑制。30、60和100 μM的PA浓度首先通过另一种对H - 7比对星形孢菌素更敏感的蛋白激酶依赖性机制引发短暂的O₂⁻产生，然后主要由独立于蛋白激酶的机制驱动持续的O₂⁻产生。在有无普萘洛尔的情况下，研究了完整PMN中外源性添加的[¹⁴C]PA8:0的代谢。结果表明，在通过上述三种不同机制诱导O₂⁻产生方面，PA本身比其二酰甘油等降解产物更重要。
