Osteogenic differentiation of human umbilical cordderived mesenchymal stem cells promoted byoverexpression of osterix

Background: Umbilical cord-derived mesenchymal stem cells (UC-MSCs) are considered to be multipotent mesenchymal stem cells that are easily induced to differentiate into functional osteoblasts both in vitro and in vivo. Osterix (Osx), a novel zinc-finger-containing transcription factor of the Sp family, is required for osteoblast differentiation and bone formation. Objective: We investigated the effect of Osx on the proliferation and osteogenic differentiation of the UC-MSCs. Method: The primary UC-MSCs were isolated and cultured. An Osx-expressing plasmid (pEGFP-Osx) was constructed and transfected into UC-MSCs. Then expression of bone morphogenesis-related genes, proliferation rate, alkaline phosphatase activity, and mineralization were examined to evaluate the osteogenic potential of the Osx gene-modified UC-MSCs. Result: UC-MSCs transfected with pEGFP-Osx exhibited apparent osteogenic differentiation as determined by increased activity of alkaline phosphatase, the formation of mineralized nodules and the expression of related osteoblastic genes. Conclusion: These results confirmed the ability of Osx to enhance osteoblast differentiation of UC-MSCs in vitro, and the Osx gene-modified UC-MSCs are potential as novel cell resources of bone tissue engineering.