Catarzi Serena, Giannoni Elisa, Favilli Fabio, Meacci Elisabetta, Iantomasi Teresa, Vincenzini Maria T
Department of Biochemical Science, University of Florence, Viale Morgagni 50, 50134, Florence, Italy.
Biochim Biophys Acta. 2007 Jun;1770(6):872-83. doi: 10.1016/j.bbagen.2007.01.008. Epub 2007 Feb 1.
This study demonstrates for the first time that sphingosine 1-phosphate (S1P) increases H2O2 production in NIH3T3 fibroblasts through NADPH oxidase activation, confirming the involvement of phosphoinositide-3-kinase and protein kinase C in the activation of this enzyme in non-phagocyte mammalian cells. The results demonstrate also that both platelet-derived growth factor (PDGF) and S1P-mediated NADPH oxidase activation and H2O2 production by Gi-protein coupled receptors (GPCRs) and c-Src kinase. Moreover, both PDGF and S1P activate c-Src kinase through GPCRs, indicating that this kinase can constitute a connection factor between PDGF and S1P signaling, confirming the cross-talk previously found between their receptors. Thus, Gi-protein-mediated NADPH oxidase activation with the consequent H2O2 increase constitutes an early event in the PDGF and S1P pathways. However, a different time course of H2O2 production in S1P-stimulated cells compared to that obtained in PDGF-stimulated cells has been observed, and this seems to be related to the different activation behavior of c-Src kinase induced after S1P or PDGF stimulation. Finally, these data demonstrate that S1P-induced H2O2 production is necessary to maximize c-Src kinase activation, confirming that this is a redox regulated kinase. After which, c-Src plays an important role both upstream and downstream from NADPH oxidase activation.
本研究首次证明，1-磷酸鞘氨醇（S1P）通过激活NADPH氧化酶增加NIH3T3成纤维细胞中H2O2的产生，证实了磷酸肌醇-3-激酶和蛋白激酶C参与非吞噬性哺乳动物细胞中该酶的激活。结果还表明，血小板衍生生长因子（PDGF）和S1P均通过Gi蛋白偶联受体（GPCRs）和c-Src激酶介导NADPH氧化酶激活和H2O2产生。此外，PDGF和S1P均通过GPCRs激活c-Src激酶，表明该激酶可构成PDGF和S1P信号传导之间的连接因子，证实了先前在其受体之间发现的相互作用。因此，Gi蛋白介导的NADPH氧化酶激活以及随之而来的H2O2增加是PDGF和S1P途径中的早期事件。然而，已观察到S1P刺激的细胞与PDGF刺激的细胞中H2O2产生的时间进程不同，这似乎与S1P或PDGF刺激后诱导的c-Src激酶的不同激活行为有关。最后，这些数据表明，S1P诱导的H2O2产生对于最大化c-Src激酶激活是必要的，证实了这是一种氧化还原调节激酶。此后，c-Src在NADPH氧化酶激活的上游和下游均发挥重要作用。
