Effect of Platelet Releasate on uPA and uPAR Gene Expression in Mesenchymal Stem Cells

Background: Mesenchymal stem cells (MSCs) as pluripotent stem cells are able to migrate toward tumor cells and inflammation due to uPA and uPAR expression in these cells and tumor cells. Platelet relesate (PR) contains different growth factors can be used for FBS replacement in cell culture medium for in vitro expansion of MSCs in cell therapy. In this study Mesenchymal cells were exposed to PR and the expression of uPA and uPAR gene and protein was investigated. Methods and Materials: Bone marrow derived MSCs were characterized by flow cytometric analysis of specific surface markers and osteoblastic differentiation ability.  These cells were cultured in the complete medium supplemented with (10% FBS), (10% PR) and (5% FBS - 5% PR) for 7 days. The PR was prepared by adding thrombin to random donor platelets derived PRP. Expression of uPA and uPAR genes was examined by Real time PCR. uPA and uPAR protein expression was assessed by Western blot. Results: The results showed that uPA and uPAR gene expression was increased significantly in two culture conditions including (5% FBS - 5% PR) and (10% PR) compared to 10% FBS (P<0.01). The highest uPA and uPAR gene expression was observed in (10% PR) and there were significant differences between (10% PR) and (5%FBS -5%releasate) (P<0.01). uPA and uPAR protein expression was detected in (5% FBS - 5 % releasate) and (10% releasate) culture condition. Conclusion: Our results was stated that use of PR in MSCs culture medium enhance expression of uPA and uPAR molecules on MSCs, and probably can be increased tropism ability to tumor cells.