
<ArticleTitle>Interaction of <prot>TGF-beta1</prot> and <prot>rhBMP-2</prot> on human bone marrow stromal cells cultured in collagen gel matrix.</ArticleTitle>
<AbstractText><prot>Transforming growth factor-beta1</prot> (<prot>TGF-beta1</prot>) and <prot>bone morphogenetic protein-2</prot> (<prot>BMP-2</prot>) are abundant proteins in the bone matrix. However, their interaction in controlling osteoblast differentiation is not clearly understood. In this study, HBMSCs were cultured in collagen gel matrix with different condition of exogenous <prot>rhBMP-2</prot> and <prot>TGF-beta1</prot> in order to determine the interaction of <prot>BMP-2</prot> and <prot>TGF-beta1</prot> on human bone marrow stromal cells (HBMSCs) differentiation. The cultured cells were analyzed for cell proliferation, <prot>alkaline phophatase</prot> (<prot>ALP</prot>) activity and mineralization staining with Von-Kossa. The cells treated with <prot>TGF-beta1</prot> exhibited a higher rate of cell growth than those without. However, the cells cultured in <prot>collagen</prot> gel matrix showed a lower rate of cell growth than the cells cultured in a monolayer. To investigate the effects of both cytokines on osteoblast differentiation, the cells were treated with 0, 1, 5, 10 ng/ml of <prot>TGF-beta1</prot> for 2 days. This was followed by culturing with 0, 1, 5, and 10 ng/ml of <prot>TGF-beta1</prot> and 100 ng/ml of <prot>rhBMP-2</prot> together for 3 days with the <prot>alkaline phosphatase</prot> (<prot>ALP</prot>) activity measured. The cells treated with 1 ng/ml of <prot>TGF-beta1</prot> responded efficiently to <prot>rhBMP-2</prot> and expressed <prot>ALP</prot> activity with a level equivalent to that exhibited by cells that were not treated with <prot>TGF-beta1</prot>. The cells treated with 5 and 10 ng/ml of <prot>TGF-beta1</prot> showed a dramatic decrease in <prot>ALP</prot> activity. The cells treated with 10 ng/ml of <prot>TGF-beta1</prot> followed by <prot>rhBMP-2</prot> alone exhibited an intermediate <prot>ALP</prot> activity. The cells treated with 100 ng/ml of <prot>rhBMP-2</prot> demonstrated Von-Kossa positive solid deposits after 3 weeks, while there were few Von-Kossa positive solid deposits when the cells treated with 10 ng/ml of <prot>TGF-beta1</prot>. These results show that <prot>TGF-beta1</prot> inhibits the effects of <prot>rhBMP-2</prot> on the osteoblast differentiation of HBMSCs in a dose dependant manner. Furthermore, the effects of <prot>TGF-beta1</prot> on HBMSCs are reversible. This suggest that <prot>TGF-beta1</prot> and <prot>rhBMP-2</prot> are coordinately controlled during the osteoblast differentiation of HMBSCs.</AbstractText>
