Sphingosine-1-phosphate inhibits H2O2-induced granulosa cell apoptosis via the PI3K/Akt signaling pathway

Objective: To investigate the protective effect of sphingosine-1-phosphate (S1P) against H2O2-induced apoptosis in human granulosa cell cultures with freshly harvested granulosa cells. Design: Experimental study. Setting: Academic medical center for reproductive medicine. Patient(s): Cultures of primary granulosa cells isolated from women undergoing in vitro fertilization (IVF). Intervention(s): None. Main Outcome Measure(s): Cell apoptosis and Western blot analysis of signaling pathway proteins. Result(s): We found that S1P (1 and 10 mM) statistically significantly decreased granulosa cell apoptosis after H2O2 treatment. The decreased cell apoptosis induced by S1P was abolished after treatment with VPC23019, an inhibitor of S1P1 and S1P3 receptors, W146, an inhibitor of S1P1 receptors, and CAY10444, an inhibitor of S1P3 receptors. A Western blot analysis revealed that the level of phospho-Akt increased and peaked at 10 minutes after 10 mM S1P exposure. Conclusion(s): Treatment with S1P can inhibit the apoptosis of granulosa cells in response to oxidative stress induced by H2O2. The protective effect of S1P is mediated by activating the PI3K/Akt pathway, and the antiapoptotic effect of S1P is mainly mediated through the S1P1 and S1P3 receptor. (Fertil Steril (R) 2012;98:1001-8. (C)2012 by American Society for Reproductive Medicine.)