The elucidation of action mechanism of enamel matrix derivative on the reconstruction of alveolar bone.

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Although enamel matrix derivative (EMD) can stimulate attachment of human periodontal ligament (HPDL) cells to the root surface, the biological mechanism of this phenomenon is unclear. Therefore, we determined which molecules in EMD are involved in the attachment of HPDL cells, and which types of integrins on the cell surface mediatethe interaction between the cells and EMD. Our results suggest that the attachment of HPDL cells to EMD can be mediated by interaction between a bone sialoprotein-like molecule and integrin αvβ3 on the cell surface (J Periodontol 2001;72:1520-1526).Although EMD initiate de novo cementum and bone formation by stimulating and inducing differentiation of mesenchymal cells in the periodontal ligament, the molecular mechanism of this phenomenon is not fully understood. Therefore, we determined the effect of EMD on the differentiation of pluripotential mesenchymal cells(C2C12 cells). C2C12 cells cultured in differentiation medium without EMD altered their phenoty … More pe to myoblasts, exhibiting positive reactions to desmin and myosin heavy chains by immunological analysis. However, the cells cultured in the presence of EMD were strongly inhibited from developing into myoblasts, and showed high alkaline phosphatase (ALPase) avtivity that was approximately 2 to 4 times greater than that of the vehicle. The mRNA expression of ALPase, osteocalcin, and type X collagen was increased markedly by the EMD-stimulated medium, whereas the expression of desmin, MyoD, and lipoprotein lipase was drastically decreased. These results suggest that. EMD converts the differentiation pathway of C2C12 cells into the osteoblast and/or chondroblast lineage (J Periodontol 2002;73:543.550).We determined the effect of β-alanyl-L-histidinato zinc (AHZ) and β-alanyl-L-histidine (carnosine) on the differentiation of HPDL cells. RUNX2/Cbfa1 expression increased markedly in cells cultured with AHZ, while Sox9 expression increased slightly. By contrast, RUNX2/Cbfa1 and Sox9 expressions increased markedly with carnosine. Bone morphogenetic protein-2 (BMP-2) and BMP-7 expressions was much higher than that of controls in cultures with AHZ and carnosine. The expression of BMP receptors increased markedly in cells cultured with AHZand carnosine. The phosphorylation of Smad1, a signal-transducing molecule for BMP-2 and BMP-7, was increased markedly in cultures with AHZ and camosine. These results suggest that AHZ and carnosine divert the differentiation pathway of HPDL cells into the osteoblast and/or chondroblast line age via the autocrine action of BMP-2 or BMP-7 produced by the cells (Dent Jpn 2003;39:114-118, Life Sciences 2004;74:2493-2504, J Periodontol Res 2004;39:in press) Less