J Korean Orthop Assoc.  2002 Feb;37(1):145-151.

The Influence of Fibronectin and/or RGDS Tetrapeptide on Osteopontin Expression in Cultures of Rat Calvarial Osteoblasts

• Han SK
• Kim HM
• Choi NY
• Kim HG
• Ha JD

Abstract

PURPOSE: To investigate the effect of fibronectin (FN) and/or RGDS tetrapeptide on osteoblastic proliferation and osteopontin expression.
MATERIALS AND METHODS
Osteoblasts were cultured on tissue culture polystyrene (TCPS) and apatite-wallastonite glass ceramics (AW-GC) with or without FN and RGDS synthetic tetrapeptide. Osteoblastic proliferation and differentiation were measured after cultivation, by determining the number of attached cells, by [3H]-thymidine assay, and by measuring the activity of alkaline phosphatase. The expression of osteopontin (OPN) was determined by RT-PCR and western blotting.
RESULTS
Cellular proliferation was more increased by FN than the other variables examined (P<0.03). OPN mRNA expression by RT-PCR was induced two-fold, 24-hour after FN treatment (P<0.05). The expression of OPN by western blotting showed a five-fold increase in cells treated with FN compared with the controls. The synthetic RGDS peptides partially blocked the growth of cells induced by FN (P<0.05). RGDS tetrapeptide alone increased the OPN expression induced by cultured osteoblasts (P<0.05).
CONCLUSION
FN enhanced osteoblastic proliferation on glass ceramics and induced OPN expression. Integrin occupancy by RGD-containing molecules may play a role in the process of osteoblastic proliferation rather than in osteoblastic differentiation.

Keyword

Osteoblast; Fibronectin; RGDS synthetic tetrapeptide; AW-GC; Osteopontin

MeSH Terms

Alkaline Phosphatase
Animals
Blotting, Western
Cell Proliferation
Ceramics
Fibronectins*
Glass
Osteoblasts*
Osteopontin*
Peptides
Polystyrenes
Rats*
RNA, Messenger
Alkaline Phosphatase
Ceramics
Fibronectins
Osteopontin
Peptides
Polystyrenes
RNA, Messenger