Enhancement of bone formation by genetically engineered human umbilical cord-derived mesenchymal stem cells expressing osterix

Objectives. The aim of this study was to investigate if overexpression of osterix (Osx) in human umbilical cord-derived mesenchymal stem cells (UC-MSCs) would facilitate osteogenic differentiation in bone regeneration. Study Design. UC-MSCs were isolated from UCs. A pEGFP-Osx plasmid was constructed and applied to transfect UC-MSCs. Cell proliferation, alkaline phosphatase (ALP) activity, and expression of bone-related genes were examined to evaluate the osteogenic potential of UC-MSCs. Bone regeneration in vivo was evaluated in nude mice using PLGA as a carrier. Results. Reverse-transcription polymerase chain reaction showed that pEGFP-Osx transfection enhanced expression of bone matrix proteins. Overexpression of Osx in UC-MSCs enhanced ALP activity, while not inhibited their proliferation rate. The Osx-transduced group formed significantly more bone at 4 weeks. Conclusions. Concerning their simple isolation and proliferation, it is believed that genetically engineered UC-MSCs could play important roles in the study and application of bone tissue engineering.