Effects of Sphingosine-1-phosphate on Proliferation and Cell-surface Markers of Human Umbilical Cord Mesenchymal Stem Cells

Sphingosine-1-phosphate(S1P) is a bioactive phospholipid molecule with multiple biological functions,such as cell proliferation,apoptosis,migration.In the present study,we found that S1P stimulated proliferation of human umbilical cord mesenchymal stem cells(hUC-MSCs).In order to clarify the signaling pathway of hUC-MSCs proliferation in response to S1P and it's effect on cell-surface markers of hUC-MSCs,we detected the level of the S1P receptors(S1PRs) mRNA by real-time PCR.MTT assay was used to measure the effects of VPC23019(S1P1/3 receptor antagonist),JTE013(S1P2 receptor antagonist),CAY10444(S1P3 receptor antagonist),PTX(Gi inhibitor) and PD98059(ERK inhibitor) on proliferation of hUC-MSCs induced by S1P.Then we checked the level of p-ERK by Western blotting.Flow cytometry was used to detect the cell-surface markers.The results showed that S1P stimulates hUC-MSCs proliferation in a dose dependent manner.S1PR1-3 mRNA was mainly expressed in hUC-MSCs and S1PR4,S1PR5 levels were low.VPC23019 completely and CAY10444 partly inhibited S1P-induced hUC-MSCs proliferation,but JTE013 had no significant effects.PTX and PD98059 inhibited S1P-induced hUC-MSCs proliferation and ERK1/2 phosphorylation.In conclusion,S1P stimulated the proliferation of hUC-MSCs through S1PR1/3,Gi and ERK1/2 signal pathway,but no effect was observed on the cell-surface markers of hUC-MSCs.