Figure 6.
Ezh2-deficient chondrocytes exhibit enhanced expression of an osteogenic-program in vitro, but genetic inactivation does not result in osteoarthritis in vivo. A, expression of chondrogenic, osteogenic, cell–cell contact/extracellular matrix, and other genes by RNA-Seq. Ezh2-deficient IMCs exhibit up-regulation of osteogenic genes on day 14 compared with WT (Ezh2wt/wt; Col2a1-Cre+/−) IMC cultures. B, osteoblast-associated genes, including Sp7(Osx) and Bmp2, the osteocyte-associated extracellular matrix gene Mepe, as well as the WNT pathway inhibitors Sost and Dkk1 are up-regulated in cKOCol2 IMC cultures. C, protein levels of the transcription factor Sp7(Osx) were also enhanced in Ezh2-deficient IMC cultures. The numbers on the right indicate the location of molecular weight markers (kilodalton). D, WT and cKOCol2 mice were aged to 24 weeks, and micro-CT analysis was performed on the right knee joint. No changes in the subchondral bone were observed (n = 4/group).