Stable Down-regulation Of Osterix By RNA Interference In Mesenchymal Stem Cells Delayed Osteogenesis, Compared To BMP-2 Stimuli, And Overtly Affect Chondrogenesis

Objective:To investigate effects of stable down-regulation of gene osterix upon osteogenesis and chondrogenesis in mesenchymal stem cells, compared to inducement of BMP-2,Materials and methods:We generated a lentivirus carrying an osterix-specific shRNA to infect MSCs and led to deficiency of endogenous osterix, and the other group was stimulated by routine osteogenic medium for inducement. Samples were isolated and collected at different time points and underwent the analysis of ELISA, real-time PCR and western blot, targeting osteogenic and chondrogenic typical marks.Results:Osterix silencing augmented expression of chondrogenic marks Sox9 and Aggrecan at early periods but repressed Runx2 and collagen X from the list of osteogenic marks, opposing to promotion of BMP-2.Conclusions: Down-regulation of osterix apparently suppressed expression levels of osteogenesis in MSCs, and definitely increased chondrogenesis over the past 21 days. Furthermore, phenomenon of hypertrophy from chondrogenic cell lines may also be eliminated via osterix silencing.