Characterization of factors controlling the differentiation of periodontal ligament cells

本研究的目的是表征控制牙周膜（PDL）细胞分化和功能的分子。我们构建了牛PDL组织的cDNA文库，克隆了钙结合蛋白S100 A4的cDNA。我们观察到S100 A4 mRNA在萌出牙的PDL中表达水平很高，PDL细胞分泌这种蛋白，其定位于胶原纤维附近。成骨细胞培养中加入重组S100 A4蛋白抑制矿化。在培养过程中，PDL细胞在机械应力下增加S100 A4的mRNA表达连同细胞骨架蛋白。尽管该蛋白在MC 3 T3-E1细胞（成骨细胞）中的表达水平较低，但抑制MC 3 T3-E1细胞中的S100 A4表达可刺激培养物中的矿化。这些结果有力地表明S100 A4是PDL组织中meranization的抑制剂。另一方面，猪釉基质衍生物（EMD）刺激牛PDL细胞和Kusa细胞（源自小鼠骨髓）的生长和分化，导致这些培养物中矿化的刺激。对成骨细胞的刺激作用也有助于牙周组织再生。因此，明确EMD和Kusa细胞中的有效分子是非常重要的。猪重组釉原蛋白刺激Kusa细胞分化，提示釉原蛋白可能是促进牙周组织再生的有效分子。

The purpose of this research was to characterize molecules which control the differentiation and function of periodontal ligament (PDL) cells. We constructed cDNA library of bovine PDL tissue and cloned cDNA of S100A4, one of the calcium binding proteins. We observed that mRNA expression level of S100A4 in PDL of erupted teeth was high and that PDL cells secreted this protein, which localized adjacent to collagen fibers. Addition of recombinant S100A4 protein to oseteoblastic culture inhibited mineralization. In culture, PDL cells under mechanical stress inceased mRNA expression of S100A4 together with cytoskeletal proteins. Although the expression level of this protein in MC3T3-E1 cells (osteoblastic cells) was low, inhibition of S100A4 expression in MC3T3-E1 cells stimulated mineraliztion in culture. These results strongly indicate that S100A4 is an inhibitor of meranlization in PDL tissue. On the other hand, porcine enamel matrix derivative (EMD) stimulated growth and differentiation of bovine PDL cells and Kusa cells (derived from mouse bone marrow), resulting the stimulation of mineralization in these culture. The stimulatory effects on osteoblastic cells could also contribute to periodontal tissue regeneration. It is important to clarify effective molecule (s) in EMD and Kusa cells are useful for this investigation. Porcine recombinant amelogenin stimulated the differentiation of Kusa cells indicating the possibility that amelogenin is the effective molecule.Although further studies are necessary, we could apply recombinant amelogenin to periodontal tissue regeneration.