There is extensive evidence that osteogenic cell differentiation is a multistep series of events mediated by an integrated cascade of gene expression. Retinoic acid has been reported as a potent regulator of cell proliferation and differentiation. Indeed, our preliminary data reveals that treatment of osteoblast-like PDL fibroblasts with retinoic acid increases the synthesis of EGF-receptor, which is only expressed in preosteoblast. This indicates that retinoic acid may act as a negative regulator for osteogenic cell differentiation. In this study, we have found that transcription factor Ets1 can be induced in MC3T3E1 cells by retinoic acid. Thus, the multiple functions of retinoic acid in bone cells are likely to be mediated in part by Ets1.
