ABSTRACT
Objective To investigate the role of transcriptional-coactivator with PDZ-binding motif( TAZ) in genistein-induced osteoblastogenic differentiation of mouse bone marrow-derived mesenchymal stem cells ( BMSCs) .Methods Mouse BMSCs were cultured in phenol red-freeα-MEM containing osteogenic supplements for inducing osteogenic differentiation.BMSCs were transfected with siRNA-TAZ and treated with genistein.The temporal sequence of osteoblastic differentiation in BMSCs cultures was assayed by measuring alkaline phosphatase activity (ALP) and calcium deposition.The mRNA expression of bone sialoprotein ( BSP) and osteocalcin ( OC) were detected by reverse transcription-polymerase chain reaction(RT-PCR).The binding interaction between TAZ and cbfa1 was identified by co-immunoprecipitation.Results TAZ expression was detected during the induction of osteogenic differentiation, the ALP activity and calcium deposition were significantly decreased in BMSCs which were transfected with siRNA-TAZ.Genistein(0.01-1 μmol/L) exhibited a dose-dependent effect on TAZ expression in mouse BMSCs cultures.Treatment with genistein ( 1 μmol/L ) resulted in increased ALP avtivity and calcium deposition of BMSC cultures as function of time.Genistein(1μmol/L) also promoted the nuclear localization of TAZ and augmented the interaction between TAZ and cbfa1, and by which upregulated cbfa1-mediated gene expression such as BSP and OC.However, the ALP avtivity and calcium deposition, as well as the expression of BSP and OC were not promoted by genistein in BMSCs transfected with siRNA-TAZ.Conclusion These data suggest that the TAZ plays an important role in genistein-induced osteoblastic differentiation of mouse BMSCs cultures.