ABSTRACT
Core binding factor ß (Cbfß) is a non-DNA binding cofactor of Runx2 that potentiates DNA binding. Previously, it has been reported that Cbfß plays an essential role in osteogenic differentiation and skeletal development by inhibition adipogenesis. Here, we delivered the recombinant Cbfß protein into human mesenchymal stem cells (MSCs) and triggered osteogenic lineage commitment. The efficient delivery of Cbfß was achieved by fusing 30Kc19 protein, which is a cell-penetrating protein derived from the silkworm. After the production of the recombinant Cbfß-30Kc19 protein in the Escherichia coli expression system, and confirmation of its intracellular delivery, MSCs were treated with the Cbfß-30Kc19 once or twice up to 300 µg/ml. By investigating the upregulation of osteoblast-specific genes and phenotypical changes, such as calcium mineralization, we demonstrated that Cbfß-30Kc19 efficiently induced osteogenic differentiation in MSCs. At the same time, Cbfß-30Kc19 suppressed adipocyte formation and downregulated the expression of adipocyte-specific genes. Our results demonstrate that the intracellularly delivered Cbfß-30Kc19 enhances osteogenesis in MSCs, whereas it suppresses adipogenesis by altering the transcriptional regulatory network involved in osteoblast-adipocyte lineage commitment. Cbfß-30Kc19 holds great potential for the treatment of bone-related diseases, such as osteoporosis, by allowing transcriptional regulation in MSCs, and overcoming the limitations of current therapies.