[Over-expression of CXCR4 promotes homing and proliferation of mouse bone marrow mesenchymal stem cells]

Objective To explore the effects of over-expression of C-X-C motif chemokine receptor 4 (CXCR4) on the homing capacity of bone marrow mesenchymal stem cells (BMMSCs) in vivo and in vitro, and the proliferation activity of BMMSCs. Methods The CXCR4-BMMSCs were constructed by the lentiviral vector-mediated BMMSC over-expressing the CXCR4 gene. The effect of chemokine SDF-1 on the migration ability of BMMSCs was detected by Transwell^TM migration assay; and MTT assay was used to detect cell proliferation. The BALB/c mice were randomly divided into two groups after receiving total body irradiation (TBI), 10 mice in each group. BMMSCs control group: mice were infused with BMMSCs (5×10⁵) transducted by EGFP via tail vein after TBI; CXCR4-BMMSC group: mice were infused with BMMSCs (5×10⁵) simultaneously transducted by GFP and CXCR4 gene via tail vein after TBI. The thymus of mice was frozen and sectioned, and fluorescence microscopy was used to observe the homing of BMMSCs into thymus tissue. Furthermore, flow cytometry was performed to detect the homing efficiency of BMMSCs to thymus in recipient mice. Results Transwell assay showed that over-expresion of CXCR4 could promote the migration and recruitment of BMMSCs to chemokine SDF-1; the proliferation activity of CXCR4-BMMSCs increased significantly compared with BMMSC control group. Compared with the control group, the frozen section showed that over-expression of CXCR4 could significantly improve the efficiency of BMMSC homing to thymus tissue. Flow cytometry suggested that CXCR4-BMMSCs homing to thymus were more than those in the control group. Conclusion Over-expression of CXCR4 gene mediated by lentivirus vector can enhance the migration and recruitment of BMMSCs by SDF-1, and promote BMMSCs homing to damaged thymus in vivo. In addition, CXCR4 also promotes the proliferation of BMMSCs.