Modeling the chondrocyte-derived osteoblasts formation process reveals its molecular signature and regulation network

Endochondral ossification is a physiological process related to the development of long bones, not only on the embryo phase, but also during postnatal development. Mouse cell lineage tracking studies and histology techniques focused on the metaphysis and growth plate area of long bones have described a phenotype transition from chondrocytes to bone cells. However, the molecular events involved in this phenotype transition is still undescribed. Aiming to reproduce this phenotype transition in in vitro cell culture context, primary mesenchymal progenitor cells have been isolated from femur heads, characterized, and cultured following a serial differentiation protocol, first using chondrogenic media and then osteogenic media. RNA samples were obtained at different cell culture time points and processed for RNAseq studies. Time points are: D7 corresponding to 7 days culture in chondrogenic media, D8 corresponding to samples obtained one day after switching to osteogenic media, D10 corresponding to samples obtained three days after switching to osteogenic media, and, D28 corresponding to samples obtained osteogenic terminal end point, compiling 7 days in chondrogenic media and 21 days in osteogenic media.