In Vitro Effects of EMD-derived Oligopeptides on Human Epithelial Cells

Objectives: Enamel matrix derivative (EMD) extracted from the tooth germ of young pigs has been used clinically as a convenient material for periodontal tissue regeneration. However, EMD might be rejected by patients, because it is an animal-derived material and may carry unknown pathogenic organisms. Development of a newly synthesized oligopeptide with the same function as EMD is desirable. The aim of the present study was to examine the effects on human gingival epithelial cells of the newly synthesized oligopeptide by using matrix-assisted laser-desorption ionization time-of-flight mass spectrometry analysis of eosinophilic round bodies formed after subcutaneous injection of EMD into the backs of rats. Methods: Human gingival epithelial cell lines (HGECs) known as epi4 was obtained from Prof. Murakami, Osaka University. The in vitro effects of the oligopeptides on HGECs at three concentrations (5, 100, 500 ng/mL) and control (0 ng/mL) were determined by examining cell proliferation/viability, adhesion and chemotaxis. Cell proliferation/viability, cell adhesion and cell chemotaxis were determined using MTS assay reagent, PicoGreen® dsDNA Quantitation Assay Reagent Kit and BD FALCON Fluoroblok Insert System by Boyden chamber method, respectively. Results: The proliferative response was enhanced by the oligopeptides at all concentrations with time. In cell proliferation/viability and adhesion assays, the fluorescent intensities at 100 ng/mL were significantly lower than at the other concentrations and control. In cell chemotaxis assay, HGEC chemotaxis at 100 ng/mL was significantly greater than the other concentrations and for the control. Conclusions: These findings suggest that the oligopeptide may not upregulate cell proliferation/viability, adhesion, or chemotaxis in a dose-dependent manner. Therefore, further investigation is needed to determine the optimal concentration of the oligopeptide to enhance wound healing responses by HGEC throughout the process of periodontal regeneration.