Effects of transforming growth factor-beta1 on the gene expression of decorin, biglycan, and alkaline phosphatase in osteoblast precursor cells and more differentiated osteoblast cells.
In this study, the effects of incubating two clonal rat osteoblastic cell lines at different stages of differentiation, ROB-C26 (C26) and ROB-C20 (C20), with transforming growth factor-beta1 (TGF-beta1) on the gene expression of decorin, biglycan, and alkaline phosphatase were examined. C26 cells are a potential osteoblast precursor cell line that is also capable of differentiating into muscle cells and adipocytes and is differentiated into osteoblasts after treatment with bone morphogenetic protein-2. C20 cells are a more differentiated osteoblastic cell line. Our Northern blot studies demonstrated that after treatment with TGF-beta1 (0, 0.1, 1.0, 5.0, and 10 ng/ml), a dose- and time-dependent decrease in decorin mRNA expression was found in C26 cells. In contrast, the effect of decorin mRNA with TGF-beta1 was not determined in C20 cells, since decorin mRNA expression was extremely low in this cell line even in the absence or presence of TGF-beta1. Although TGF-beta1 treatment resulted in no appreciable effect on biglycan mRNA expression in both cell lines in a dose- and time-dependent manner, it decreased significantly the expression of alkaline phosphatase in both cell lines at the gene and protein level. Reverse transcriptase-polymerase chain reaction analysis revealed the gene expression of decorin, and TGF-beta type I and type II receptors in both cell lines. These results indicate that osteoblasts progenitor cells express both decorin and biglycan mRNAs. In contrast, more differentiated and mature osteoblastic cells express preferentially biglycan mRNA. TGF-beta1 exerts different effects on the expression of decorin and biglycan mRNAs, and is a potent inhibitor of the gene expression of alkaline phosphatase during osteoblast differentiation.
Yamada
T
T
Department of Anatomy, Nihon University School of Dentistry, Tokyo, Japan.
Kamiya
N
N
Harada
D
D
Takagi
M
M
D000469:Alkaline Phosphatase / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D058578:Biglycan; D002454:Cell Differentiation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003470:Culture Media; D058575:Decorin; D016326:Extracellular Matrix Proteins; D015870:Gene Expression / Q000187:drug effects; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D011509:Proteoglycans / Q000235:genetics*; D051381:Rats; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology
C546886:Bgn protein, rat; D058578:Biglycan; D003470:Culture Media; C546880:Dcn protein, rat; D058575:Decorin; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D000469:Alkaline Phosphatase