Identification of osteo-adipo co-progenitors from adipose tissues

Objectives: Recent research findings postulate that adipocytes and osteocytes may share a common progenitor. However, the interlinking pathways between adipose tissue and bone, and the differentiation potential of cells to convert from one tissue into the other via progenitor cells have not been elucidated and are therefore the focus of this study. Methods: We identified that a few of cells derived from the adipose stromal cells express both osteo and adipo petential differentiation abilities. Results: The cells that can be enriched in the Sca-1- population contained cytoplasm Runx2 and PPAR-ã proteins and the mRNAs specifically exprssing in the oesteo or adipo lineage. After induced into adipogenesis, PPAR-ã enters the nucleus and the cells differentiate into adipocytes. The Runx2 remained in the cytoplasm and decreased during adipogenesis. In contrast, when the cells were induced into osteogenesis, the Runx2 got into the nucleus and the cells turned to the osteocytes. Conclusions: Our results indicate that there are osteo-adipo progenitors in the fat tissue and suggest that the osteogenic, adipogenic differentiations of mesenchymal stem cells come from the same progenitors.