Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Bilbao, Spain.
Am J Physiol Endocrinol Metab. 2013 Jun 1;304(11):E1213-26. doi: 10.1152/ajpendo.00480.2012. Epub 2013 Apr 2.
The bioactive sphingolipid ceramide 1-phosphate (C1P) is implicated in inflammatory responses and was recently shown to promote cell migration. However, the mechanisms involved in these actions are poorly described. Using J774A.1 macrophages, we have now discovered a new biological activity of C1P: stimulation of monocyte chemoattractant protein-1 (MCP-1) release. This novel effect of C1P was pertussis toxin (PTX) sensitive, suggesting the intervention of Gi protein-coupled receptors. Treatment of the macrophages with C1P caused activation of the phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase kinase (MEK)/extracellularly regulated kinases (ERK), and p38 pathways. Inhibition of these kinases using selective inhibitors or specific siRNA blocked the stimulation of MCP-1 release by C1P. C1P stimulated nuclear factor-κB activity, and blockade of this transcription factor also resulted in complete inhibition of MCP-1 release. Also, C1P stimulated MCP-1 release and cell migration in human THP-1 monocytes and 3T3-L1 preadipocytes. A key observation was that sequestration of MCP-1 with a neutralizing antibody or treatment with MCP-1 siRNA abolished C1P-stimulated cell migration. Also, inhibition of the pathways involved in C1P-stimulated MCP-1 release completely blocked the stimulation of cell migration by C1P. It can be concluded that C1P promotes MCP-1 release in different cell types and that this chemokine is a major mediator of C1P-stimulated cell migration. The PI3K/Akt, MEK/ERK, and p38 pathways are important downstream effectors in this action.
生物活性神经酰胺 1-磷酸（C1P）参与炎症反应，并被证明可促进细胞迁移。然而，这些作用的机制还描述得很差。使用 J774A.1 巨噬细胞，我们现在发现了 C1P 的一个新的生物学活性：刺激单核细胞趋化蛋白 1（MCP-1）释放。C1P 的这种新作用对百日咳毒素（PTX）敏感，表明 Gi 蛋白偶联受体的干预。用 C1P 处理巨噬细胞会导致磷脂酰肌醇 3-激酶（PI3K）/Akt、丝裂原激活蛋白激酶激酶（MEK）/细胞外调节激酶（ERK）和 p38 途径的激活。使用选择性抑制剂或特异性 siRNA 抑制这些激酶会阻断 C1P 对 MCP-1 释放的刺激。C1P 刺激核因子-κB 活性，阻断这种转录因子也会导致 MCP-1 释放的完全抑制。此外，C1P 刺激人 THP-1 单核细胞和 3T3-L1 前脂肪细胞中 MCP-1 的释放和细胞迁移。一个关键的观察结果是，用中和抗体隔离 MCP-1 或用 MCP-1 siRNA 处理会消除 C1P 刺激的细胞迁移。此外，抑制 C1P 刺激的 MCP-1 释放所涉及的途径完全阻断了 C1P 刺激的细胞迁移。可以得出结论，C1P 促进不同细胞类型中 MCP-1 的释放，并且这种趋化因子是 C1P 刺激的细胞迁移的主要介质。PI3K/Akt、MEK/ERK 和 p38 途径是这种作用的重要下游效应物。
