The sphingosine kinase 1/sphingosine-1-phosphate pathway mediates COX-2 induction and PGE2 production in response to TNF-α
The sphingosine kinase 1/sphingosine-1-phosphate pathway mediates COX-2 induction and PGE2 production in response to TNF-α
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DOI：
10.1096/fj.02-1038com
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发表时间：
2003-08-01
期刊：
影响因子：
4.8
通讯作者：
Hannun, YA
中科院分区：
文献类型：
--
作者：
Pettus, BJ;Bielawski, J;Hannun, YA
在这项研究中，我们解决了鞘脂代谢在炎症反应中的作用。在L929成纤维细胞模型中，肿瘤坏死因子-α（TNF）在4 h诱导前列腺素E-2（PGE（2））产生，早在2 h诱导环氧合酶-2（考克斯-2）产生。考克斯-2选择性抑制剂NS 398可抑制TNF诱导的PGE（2）生成。GC-MS分析显示，只有考克斯-2产生的前列腺素类响应于TNF产生，从而提供了考克斯-2选择性的进一步证据。由于鞘脂参与介导TNF的几种作用，因此评价了它们在考克斯-2诱导和PGE（2）产生中的作用。1-磷酸鞘氨醇（S1 P）以剂量反应方式诱导考克斯-2和PGE（2），表观ED 50为100-300 nM。相关的鞘脂鞘氨醇也诱导PGE（2），尽管效果要小得多。TNF诱导鞘氨醇-1-磷酸水平增加3.5倍，在10分钟，迅速恢复到基线40分钟。小干扰RNA（siRNA）针对小鼠SK 1减少（通常为80%）SK 1蛋白和抑制TNF诱导的SK活性。用针对SK 1而非SK 2的RNAi处理细胞几乎完全消除了TNF诱导考克斯-2或产生PGE的能力（2）。相比之下，用针对S1 P裂解酶或S1 P磷酸酶的RNAi处理的细胞增强了考克斯-2的诱导，导致PGE的产生增强（2）。用SK 1 RNAi处理也消除了外源性鞘氨醇和神经酰胺对PGE的影响（2），揭示鞘氨醇和神经酰胺的作用是由于细胞内代谢成S1 P。总的来说，这些结果提供了新的证据，SK 1和S1 P是TNF诱导考克斯-2和PGE（2）产生所必需的。基于这些发现，这项研究表明SK 1和S1 P可能与病理性炎症性疾病和癌症有关。
In this study we addressed the role of sphingolipid metabolism in the inflammatory response. In a L929 fibroblast model, tumor necrosis factor-alpha (TNF) induced prostaglandin E-2 (PGE(2)) production by 4 h and cyclooxygenase-2 (COX-2) induction as early as 2 h. This TNF-induced PGE(2) production was inhibited by NS398, a COX-2 selective inhibitor. GC-MS analysis revealed that only COX-2-generated prostanoids were produced in response to TNF, thus providing further evidence of COX-2 selectivity. As sphingolipids have been implicated in mediating several actions of TNF, their role in COX-2 induction and PGE(2) production was evaluated. Sphingosine-1-phosphate (S1P) induced both COX-2 and PGE(2) in a dose-responsive manner with an apparent ED50 of 100-300 nM. The related sphingolipid sphingosine also induced PGE(2), though with much less efficacy. TNF induced a 3.5-fold increase in sphingosine-1-phosphate levels at 10 min that rapidly returned to baseline by 40 min. Small interfering RNAs (siRNAs) directed against mouse SK1 decreased (typically by 80%) SK1 protein and inhibited TNF-induced SK activity. Treatment of cells with RNAi to SK1 but not SK2 almost completely abolished the ability of TNF to induce COX-2 or generate PGE(2). By contrast, cells treated with RNAi to S1P lyase or S1P phosphatase enhanced COX-2 induction leading to enhanced generation of PGE(2). Treatment with SK1 RNAi also abolished the effects of exogenous sphingosine and ceramide on PGE(2), revealing that the action of sphingosine and ceramide are due to intracellular metabolism into S1P. Collectively, these results provide novel evidence that SK1 and S1P are necessary for TNF to induce COX-2 and PGE(2) production. Based on these findings, this study indicates that SK1 and S1P could be implicated in pathological inflammatory disorders and cancer.