[The effects of transforming growth factor beta 1 on mouse osteoblastic cell line MC3T3-E1--especially on gene expression of differentiation markers].
Regulation of alpha 2(I) collagen and osteonectin/SPARC gene expressions in mouse osteoblastic MC3T3-E1 cells by TGF-beta 1 was studied. TGF-beta 1 regulated those differentiation markers of osteoblast phenotypes, although the effects were inconsistent depending on serum concentrations. Exposure of MC3T3-E1 cells to TGF-beta 1 in low serum culture caused stimulation of alpha 2(I) collagen and osteonectin expressions but no stimulation in high serum culture. These inconsistent responses may be due to the presence of some component(s) in serum. bFGF also suppressed stimulation by TGF-beta 1 on alpha 2(I) collagen and osteonectin expressions. Serum factors as well as locally derived growth factors may interact with TGF-beta 1 and modulate the actions of TGF-beta 1 in osteoblastic cells. The present result explains the complexity of TGF-beta 1 actions on bone cells in vitro and also suggests that the actions on bone formation are modified by other factors in vivo.
Nifuji
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First Department of Oral Surgery, Faculty of Dentistry, Tokyo Medical and Dental University.
D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D003094:Collagen / Q000235:genetics*; D015870:Gene Expression; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D015676:Osteonectin / Q000235:genetics*; D015291:Transforming Growth Factors / Q000494:pharmacology*
D015676:Osteonectin; D015291:Transforming Growth Factors; D003094:Collagen