Effects of bone morphogenetic protein-2 and transforming growth factor-beta1 on gene expression of decorin and biglycan by cultured osteoblastic cells.
The influence of bone morphogenetic protein-2 (BMP-2) and transforming growth factor beta (TGF-beta) on the expression of small proteoglycans, decorin and biglycan was investigated in a clonal rat osteoblastic cell line, ROS-C26 (C26) cells, which is a potential osteoblast precursor cell line and capable of differentiating into mature osteoblasts after treatment with recombinant BMP-2 (rhBMP-2). Following the culture of C26 cells for 3, 6, and 9 days in the presence or absence of rhBMP-2, alkaline phosphatase activity increased in the rhBMP-2 treated cells in direct proportion to their differentiation into more mature osteoblastic cells, whereas decorin mRNA decreased in the cells, when compared to control cells without rhBMP-2 treatment. These results were evident 6 days after treatment. However, rhBMP-2 treatment had no effect on biglycan mRNA expression in the cells. Subsequently, after removal of rhBMP-2 from the culture media, the cells were further cultured for 24 h with graded concentrations of TGF-beta1 (0, 0.1, 1.0, 5.0, and 10 ng/ml). TGF-beta1 decreased decorin mRNA expression in the cells dose dependently, but did not affect their biglycan mRNA expression. Furthermore, either removal of rhBMP-2 from the culture media or addition of TGF-beta1 significantly decreased alkaline phosphatase activity of rhBMP-2-induced cells. These results indicate that osteoblastic differentiation is accompanied by increased alkaline phosphatase activity and decreased expression of decorin mRNA, but continuous expression of biglycan mRNA. Both rhBMP-2 and TGF-beta1 inhibit decorin mRNA expression in osteoblasts at varying stages of differentiation, but their effects on biglycan mRNA expression and alkaline phosphatase are different.
Takagi
M
M
Department of Anatomy, Nihon University School of Dentistry, Tokyo, Japan.
Yamada
T
T
Kamiya
N
N
Kumagai
T
T
Yamaguchi
A
A
D000469:Alkaline Phosphatase / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D058578:Biglycan; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D002460:Cell Line; D002999:Clone Cells; D058575:Decorin; D016326:Extracellular Matrix Proteins; D015870:Gene Expression / Q000187:drug effects; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*; D011509:Proteoglycans / Q000187:drug effects / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D015291:Transforming Growth Factors / Q000037:antagonists & inhibitors
C546886:Bgn protein, rat; D058578:Biglycan; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; C546880:Dcn protein, rat; D058575:Decorin; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D012333:RNA, Messenger; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D015291:Transforming Growth Factors; D000469:Alkaline Phosphatase