2009 Volume 7 Issue 3 Pages 152-158
It is known that coating a titanium surface with fibronectin or functional domain peptide, Arg-Gly-Asp (RGD), improves initial cell attachment and supports osteoblastic cell differentiation. However, the differences in gene expression in osteoblasts grown on fibronectin-coated titanium (FN-Ti) disks and titanium disks coated with Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) peptide (GRGDSP-Ti) have not been elucidated. Thus, such coated disks were prepared and MC3T3-E1 osteoblastic cells were cultured on their surfaces. After 15 days, the levels of gene expression in the cells were examined. Most of the expression levels were similar between the two cultures ; however, the mRNA level of otoraplin (OTOR) was significantly greater in cells cultured on the FN-Ti disks compared to those cultured on the GRGDSP-Ti disks. The elevated OTOR mRNA levels were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR. Because OTOR is known to support cartilage development and maintenance, the elevated gene expression of OTOR in osteoblast precursor cells grown on fibronectin may play a role in osteoblastic differentiation and matrix bone mineralization. Fibronectin possesses the binding domain not only for RGD but also for fibrin, proteoglycan, and collagen, so higher OTOR gene expression may be induced by later ligands. For the future development of biomaterial-modified titanium implants using synthetic peptides, binding domains other than the RGD domain in fibronectin may be useful and important.
