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

虽然牙釉质基质衍生物（EMD）可以刺激人牙周韧带（HPDL）细胞与根表面的附着，但这一现象的生物学机制尚不清楚。因此，我们确定了EMD中的哪些分子参与了HPDL细胞的附着，以及细胞表面哪种类型的整合素介导了细胞与EMD之间的相互作用。我们的研究结果表明HPDL细胞对EMD的附着可以通过骨唾液蛋白样分子和细胞表面整合素αvβ3的相互作用介导（J Periodontol, 2001;72:1520-1526）。虽然EMD通过刺激和诱导牙周韧带间充质细胞的分化来启动牙骨质和骨的新生形成，但这一现象的分子机制尚不完全清楚。因此，我们确定了EMD对多能间充质细胞（C2C12细胞）分化的影响。在未添加EMD的分化培养基中培养C2C12细胞，其表型发生改变，更倾向于成肌细胞，免疫分析显示对desmin和myosin重链有阳性反应。然而，在EMD存在下培养的细胞被强烈抑制成肌细胞的发育，并且显示出高碱性磷酸酶（ALPase）活性，大约是载体的2至4倍。emd刺激后，ALPase、骨钙素和X型胶原mRNA表达显著升高，而desmin、MyoD和脂蛋白脂肪酶mRNA表达显著降低。这些结果表明。EMD将C2C12细胞的分化途径转化为成骨细胞和/或成软骨细胞谱系（J牙周病杂志2002；73:543.550）。测定β-丙烯酰- l-组氨酸锌（AHZ）和β-丙烯酰- l-组氨酸（肌肽）对HPDL细胞分化的影响。在AHZ培养的细胞中，RUNX2/Cbfa1的表达明显增加，而Sox9的表达略有增加。相比之下，RUNX2/Cbfa1和Sox9的表达随着肌肽的增加而显著增加。骨形态发生蛋白-2 （BMP-2）和BMP-7的表达在AHZ和肌肽的培养中明显高于对照组。在AHZand肌肽培养的细胞中，BMP受体的表达明显增加。Smad1是BMP-2和BMP-7的信号转导分子，在AHZ和camosine的培养中，Smad1的磷酸化显著增加。这些结果表明AHZ和肌肽通过细胞产生的BMP-2或BMP-7的自分泌作用将HPDL细胞分化为成骨细胞和/或成软骨细胞（Dent Jpn 2003;39:114-118, Life Sciences 2004;74:2493-2504, J Periodontol Res 2004;39:in press）

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