Study of osteopontin synthesis and the expression during dentinogenesis

我们发现大鼠克隆牙髓细胞RDP4-1和RPC-C2a分泌骨桥蛋白(OPN)。牙髓OPN被高度磷酸化，并通过凝血酶敏感性和大鼠OPN单抗的免疫沉淀进行鉴定。1，25-二羟基维生素D3(1，25D3)可促进OPN的表达和合成。据报道，这种1，25D3的增加模式在许多成骨细胞中都观察到，如头盖骨和骨髓。磷酸化骨桥蛋白的合成在10^&lt；-10&gt；-10^&lt；-7&gt；M水平呈剂量依赖性增加，并在加入12，5D3后48h达到最大水平。Northern杂交结果显示，1，25D3能显著提高两种克隆牙髓细胞系OPN基因的表达水平。本研究表明这些细胞能够产生骨桥蛋白，1，25D3通过从头合成和转录调控的机制刺激骨桥蛋白的表达。

We found that rat clonal dental pulp cells, RDP4-1 and RPC-C2A eclls, produce and secrete osteopontin(OPN). The dental pulp OPN was highly phosphorylated and identified by thrombin susceptibility and immunoprecipitation with rat monoclonal OPN antibody. OPN expression and synthesis were increased by 1,25-dihydroxyvitamin D3(1,25D3). This increase pattern by 1,25D3 was reportedly observed in many osteoblastic cells such as calvaria and bone marrow. Phosphorylated OPN synthesis increased dose-dependently at 10^<-10>-10^<-7> M levels and showed maximum level at 48 h after addition of 12,5D3. Northern hybridization analysis revealed that 1,25D3 greatly increased the level of OPN mRNA in both clonal dental pulp cell lines. This study indicates that these cells can produce OPN and that 1,25D3 stimulate the OPN expression by a mechanism which involves de novo synthesis and transcriptional control.