Effects of C-terminal amelogenin peptides on the metabolism of osteoblasts

Objectives: Amelogenins, enamel matrix proteins secreted by ameloblasts, comprise 90% of the developing extracellular enamel matrix. Recent evidence suggests that amelogenins might induce the proliferation of various cells. However, the residues comprising the active site of amelogenin remain unclear. Therefore, this study aimed to examine the effects of a human amelogenin C-terminal peptide (amgCP) on the metabolism of osteoblasts. Materials and methods: Mouse calvarial osteoblastic cells (MC3T3-E1) were cultured and treated with amgCP. Cell proliferation was measured using MTS and BrdU assays. After confluence was reached, the cells were cultured in osteogenic differentiation medium and treated with 0, 100, or 1000 ng/ml amgCP. Cell differentiation activity was examined by real-time PCR, western blotting, and ALP activity. Mineralization was evaluated by Alizarin red staining. Results: Cell numbers of MC3T3-E1 were significantly (P < 0.05) increased by treatment with 1000 ng/ml amgCP as compared to the control group at 4 and 6 days. In addition, the proliferative activity of MC3T3-E1 was significantly enhanced by treatment with 100 or 1000 ng/ml amgCP. The mRNA levels and protein expressions of ALP and BSP were not changed by treatment with amgCP as compared to the non-treated controls on days 7 and 14. The osteogenic differentiation of MC3T3-E1 cells was not affected by treatment with amgCP as compared with untreated controls. Conclusion: The C-terminus of amelogenin promotes the proliferation of MC3T3-E1 cells, indicating the possible utility of the C11 peptide in bone-tissue regeneration. (C) 2016 Elsevier Inc. All rights reserved.