Transforming growth factor beta 1 stimulates type II collagen expression in cultured periosteum-derived cells.
Chondrogenesis can occur during a bone repair process, which is related to several growth factors. Transforming growth factor beta 1 (TGF-beta 1) downregulates the expression of type II collagen by chondrocytes in vitro, but injection of TGF-beta 1 into the periosteum in vivo increases type II collagen mRNA levels and initiates chondrogenesis. We examined the effect of TGF-beta 1 on collagen gene expression in a bovine periosteum-derived cell culture system to evaluate its direct effect on the periosteum. Cultured cells expressed alkaline phosphatase and collagen pro alpha 1(I) and pro alpha 1(II) mRNAs. A low level of type II collagen synthesis was demonstrated by immunoprecipitation. TGF-beta 1 had no effect on periosteal cell proliferation. Expression of collagen pro alpha 1(I) mRNA did not change with TGF-beta 1 treatment, but alkaline phosphatase mRNA showed a dose-dependent decrease. Expression of collagen pro alpha 1(II) mRNA was stimulated 2.7-fold by TGF-beta 1. TGF-beta 1 also caused a 2.6-fold increase in type II collagen synthesis by immunoprecipitation. These findings indicate that TGF-beta 1 is an enhancer of the expression of the chondrocyte phenotype of the periosteal cells and suggest that TGF-beta 1 is important in initiating and promoting cartilage formation in vivo.
Izumi
T
T
Orthopaedic Research Unit, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, Maryland.
Scully
S P
SP
Heydemann
A
A
Bolander
M E
ME
D000469:Alkaline Phosphatase / Q000235:genetics; D000818:Animals; D015152:Blotting, Northern; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects*; D010521:Periosteum / Q000166:cytology / Q000187:drug effects*; D011233:Precipitin Tests; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D016212:Transforming Growth Factor beta; D003094:Collagen; D000469:Alkaline Phosphatase