A Human Amelogenin-Derived Oligopeptide Enhances Osteogenic Differentiation of Human Periodontal Ligament Stem Cells

Abstract

We have found newly synthesized peptide derived from commercially available Emdogain® for periodontal tissue regeneration therapies in our previous study. That synthesized peptide consisted of seven amino acid sequence, WYQNMIR, which is exon 5 of porcine amelogenin and had the same effects as Emdogain®. The amino acid sequence of human amelogenin exon 5 is WYQSIR which both N (asparagine) and M (methionine) in porcine amelogenin are replaced by S (serine). In the present study, we investigated the effect of a synthetic human amelogenin-derived peptide (HAP) consisting of WYQSIR on human periodontal ligament stem cells (PDLSCs) to be useful or not for the tissue regeneration. PDLSCs were isolated from third molars of adult donors. The effect of HAP on PDLSCs was investigated by culturing them in normal or osteogenic medium with and without HAP. Proliferation of the PDLSCs was evaluated using a cell proliferation assay after they had been treated with HAP (ranging from 1 ng/ml to 10,000 ng/ml) for 1, 3, 5, and 7 days. Osteogenic differentiation was evaluated by measuring alkaline phosphatase (ALP) activity, calcium deposition, osteocalcin production, and mRNA expression of Runx2 and osteonectin after the PDLSCs had been treated with HAP (1,000 ng/ml) for 1, 7, 14, and 21 days. The number of viable cells was significantly increased in the presence of HAP in normal medium. Compared to cells cultured without HAP in osteogenic medium, cells cultured with HAP showed significantly increased ALP activity, calcium deposition, osteocalcin production, and Runx2 mRNA expression. The results show that HAP enhances proliferation and osteogenic differentiation of PDLSCs. The present study suggests that HAP may be a useful material for periodontal tissue regeneration.