Elucidating Molecular Mechanism For Lysophospholipids Induced Proliferation Of Human Umbilical Cord Mesenchymal Stem Cells And Its The Effects On Expression Of The Cell Surface Markers

Mesenchymal stem cells (MSCs) are sorts of somatic stem cells with the ability of self-renewal and multi-differentiation, these cells were able to also differentiate into the osteogenic, chondrogenic and adipogenic lineages under various culture conditions. MSCs may have a significant applied in the field of cell therapy and tissue engineering. HUC-MSCs avoid the ethical and technical issues involved in the use of cells from other origins. However, hUC-MSCs have many problems in the clinical treatment. The most significant problem is thought to obtain enough of cells to use in the clinical requirements.Sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) are two molecular species of LPs. Although some studies indicate that LPs stimulate cell proliferation, the molecular mechanism by which S1P and LPA induced proliferation and differentiation of hUC-MSCs remains largely unknown. The aim of this study is to clear the action of SIP and LPA in hUC-MSC proliferation and its signaling pathways and the effects on expression of the cell surface markers.MTT assay was used to measure the proliferation rate of hUC-MSCs stimulated by S1P and LPA. Real time PCR was used to detect the level of LPs receptors expresed in hUC-MSCs. The effects of S1PR1/3antagonist, S1PR2antagonist, S1PR3antagonist, Gi inhibitor, ERK inhibitor, PI3K inhibitor on proliferation of hUC-MSCs induced by S1P, LPA were performed. Then we checked the level of ERK1/2phosphorylation by western blot. Flow cytometer used to be detected the cell surface markers of hUC-MSCs.Our results showed that SIP, LPA stimulates hUC-MSCs proliferation with a dose dependent manner. S1PR1-3mainly expresesd in hUC-MSCs. S1PR1/3antagonist completely and S1PR3antagonist partly inhibited SIP induced hUC-MSCs proliferation and ERK1/2phosphorylation. LPAR1/3antagonist completely inhibited LPA induced hUC-MSCs proliferation and ERK1/2phosphorylation. Gi inhibitor, ERK inhibitor completely inhibited SIP, LPA induced hUC-MSCs proliferation and ERK1/2phosphorylation. S1PR2antagonist, PI3K inhibitor has no significant effects. No influence was observed the changes of the cell surface markers with S1P and LPA treatment.Conclusion:S1P stimulates the proliferation of hUC-MSCs through S1PR1/3/Gi/ERK1/2signaling pathway. LPA stimulates the proliferation of hUC-MSCs through LPAR1/Gi/ERK1/2signaling pathway. The cell surface markers (multipotency) are not effected by S1P either LPA. The study provides the new strategies of the clinical requirements of hUC-MSCs, our findings are also useful to develop the serum-free culture system for hUC-MSCs culture.