Regulation of osteogenic function of periodontal ligament fibroblast by 1d, 25-dihydroxy vitamin D3 receptor inducing factor.

1 α，25-二羟维生素D_3受体诱导因子对牙周膜成纤维细胞成骨功能的调控牙周膜成纤维细胞（PLF）的细胞功能不仅受外源性因子如激素和细胞因子的调节，而且还受PLF衍生的内源性因子的调节。25-二羟维生素D3受体（VDR）以自分泌方式。在本研究中，我们首先检测了已知的生长因子是否也能诱导PLF中VDR的表达，VDR mRNA的表达被IGF-I、IGF-II和EGF诱导，而不被TGF-β诱导。这表明VDR在PLF中的表达可能受到包括这些生长因子在内的多种自分泌因子的调节。因此，我们试图鉴定出PLF的特异性基因，并从该特异性基因的特性的角度来研究PLF的功能。利用融合的PLF和牙龈成纤维细胞（GF）构建了一个可能含有PLF特异性基因的消减cDNA文库，经Southern杂交鉴定出34个克隆，其中5个为未知基因，另1个与部分已知基因高度同源。在已知的基因中，包括与细胞分化和增殖相关的nm 23蛋白或v-fos转化效应蛋白。这些特异性基因的获得可能与PLF的细胞分化或成骨功能以外的其他重要功能有关，因为它们是与同一个体的GF比较获得的。有必要将这些基因在PLF的功能中进行分类，并检查特定基因的表达模式在PLF的分化阶段之间是否不同。

Regulation of osteogenic function of periodontal ligament fibroblast by 1alpha, 25-dihydroxyvitamin D3 receptor inducing factorCellular function of periodontal ligament fibroblasts (PLF) is regulated not only by exogenous factors such as hormones and cytokines, but also by endogenous factors derived from PLF.We have previously demonstrated that multilayred PLF produce a factor (s) which can induce the expression of 1alpha, 25-dihydroxyvitamin D3 receptor (VDR) in an autocrine manner. In this study, we first examined whether known growth factors could also induce the expression of VDR in PLF.The expression of VDR mRNA was induced by IGF-I,-II and EGF,but not by TGF-beta. This indicated that the expression of VDR in PLF could be regulated by several autocrine factors including these growth factors. We, therefore, tried to identify a gene (s) which is specific for PLF,and aimed to study the functions of PLF from a view point of the charactaristics of specific gene. Using confluent PLF and gingival fibroblasts (GF), we constructed a subtraction cDNA library which possibly contained several specific genes for PLF.34 clones were identified by Southern hybridization ; 5 were unknown genes and the other were highly homologous with a part of some known genes. Among the known genes, nm 23 protein or v-fos transformation effector protein, which were related to cell differentiation and proliferation, were included. These specific genes we obtained also might be related to some other important functions of PLF besides cell differentiation or osteogenic function, because they were obtained in comparison with GF from a same individual. It is necessary to classify these genes in the functions of PLF,and to examine whether the expression pattern of the specific gene is different among the differentiation stages of PLF.