Abstract:

Objective To understand whether Bmi-1(B cell specific moloney murine leukemia virus insertion site 1) gene participates the proliferation and senescence of mesenchymal stem cells isolated from human fetal bone marrow.
Methods Mesenchymal stem cells were transfected by lentiviral vectors encoding human-Bmi-1 or GFP. At 0, 72, 120 and 168 h after transfection, the Bmi-1 mRNA transcription level was measured by Real-time PCR and the relative expression level was calculated by the formula:(Bmi-1/GAPDH of RNAi group)/(Bmi-1/GAPDH of GFP control). The cell number of BrdU incorporation and senescence were observed under microscope.
Results The transfection efficiency, identified by GFP fluorescence, was more than 90% in both human-Bmi-1 RNAi group and GFP control group. At 0 h, 72 h, 120 h, and 168 h after transfection, the relative expression level of Bmi-1 was(100±21)%, (28±18)%, (55±21)% and (58±22)%. Compared with 0 h, the relative expression level of Bmi-1 at 72 h, 120 h and 168 h was significantly decreased. Furthermore, the number of senescent cells increased significantly after Bmi-1 knockout.
Conclusion Bmi-1 participates in the maintenance of proliferation and juvenescence of MSCs, which is isolated from human fetal bone marrow.

Key words: mesenchymal stem cells, Bmi-1, senescence, proliferation