The effects of Sp7/Osterix gene silencing in the chondroprogenitor cell line, ATDC5

► ATDC5 cells express Osx that is an essential regulator of osteoblast differentiation. ► Osx gene silencing down-regulated expression of chondrogenic factors such Sox9, Dlx5 and ALP. ► BMP2 stimulation rescued Osx expression accompanied by up-regulation of ALP and Dlx5 in Osx gene silencing cells. ► Osx gene silencing inhibited the expression of the hypertrophic chondrocyte marker gene, type X collagen in insulin treated cells.