Porcine enamel protein fractions contain transforming growth factor-beta1.
BACKGROUND
Enamel extracts are biologically active and capable of inducing osteogenesis and cementogenesis, but the specific molecules carrying these activities have not been ascertained. The purpose of this study was to identify osteogenic factors in porcine enamel extracts.


METHODS
Enamel proteins were separated by size-exclusion chromatography into four fractions, which were tested for their osteogenic activity on osteoblast-like cells (ST2) and human periodontal ligament (HPDL) cells.


RESULTS
Fraction 3 (Fr.3) and a transforming growth factor-beta 1 (TGF-beta1) control reduced alkaline phosphatase (ALP) activity in ST2 but enhanced ALP activity in HPDL cells. The enhanced ALP activity was blocked by anti-TGF-beta antibodies. Furthermore, using a dual-luciferase reporter assay, we demonstrated that Fr.3 can induce the promoter activity of the plasminogen activator inhibitor type 1 (PAI-1) gene.


CONCLUSIONS
These results show that the osteoinductive activity of enamel extracts on HPDL cells is mediated by TGF-beta1.
Nagano
Takatoshi
T
Department of Periodontics and Endodontics, School of Dental Medicine, Tsurumi University, Yokohama, Japan. nagano-takatoshi@tsurumi-u.ac.jp
Oida
Shinichiro
S
Suzuki
Shinichi
S
Iwata
Takanori
T
Yamakoshi
Yasuo
Y
Ogata
Yorimasa
Y
Gomi
Kazuhiro
K
Arai
Takashi
T
Fukae
Makoto
M
D000469:Alkaline Phosphatase / Q000187:drug effects; D000818:Animals; D002478:Cells, Cultured; D003746:Dental Enamel Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D006801:Humans; D008934:Mitogens / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects; D013552:Swine; D014020:Tissue Extracts; D053773:Transforming Growth Factor beta1 / Q000302:isolation & purification* / Q000494:pharmacology
D003746:Dental Enamel Proteins; D008934:Mitogens; D017395:Plasminogen Activator Inhibitor 1; D014020:Tissue Extracts; D053773:Transforming Growth Factor beta1; D000469:Alkaline Phosphatase