Instruction of mesenchymal cell fate by the transcription factor C/EBPβ.

The transcription factor CCAAT/enhancer binding protein beta (C/EBPβ) plays a role in the differentiation of a large variety of cell types. C/EBPβ was initially described as an early inducer of adipocyte differentiation, however, recent data have shown that this is not the only mesenchymal cell lineage where C/EBPβ has an instructive function. Mouse models and tissue culture studies have now established a regulatory role of C/EBPβ in osteoblast and in chondrocyte differentiation. These three different cell lineages are derived from the same precursor, the mesenchymal stem cell (MSC). This review will focus on the emerging role of C/EBPβ and its different protein isoforms in various mesenchymal cell lineages and its function in adipocyte, chondrocyte and osteoblast differentiation. Moreover, the mesenchymal stem cell has attracted the attention of regenerative medicine in recent years, and the possible role of C/EBPβ in this respect will be discussed.