Molecular biological study of the function of matrix proteins in the early stage of tooth development, with special reference to cytodifferentiation and initial calcification

牙齿发育早期基质蛋白功能的分子生物学研究，特别是细胞分化和初始钙化

基本信息

批准号：
18592002
负责人：
UCHIDA Takashi
金额：
$ 2.57万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Sheath protein (ameloblastin), one of the main constituent of the enamel matrix protein, is expressed not only in the secretory ameloblast but also in other cell types such as immature odontoblasts and epithelial cell rest of Malassez. In order to understand the role of Sheath protein in the epithelial-mesenchymal interaction, we have attempted to demonstrate the expression of sheathe protein and the relation of cement blast differentiation of the earliest stage of the cementgenesis in the rat moral tooth germs and incisors. The results are summarized as follows.1. A part of cells in the Hertwig's epithelial root sheath and the epithelial cell rest of Malassez expressed sheath protein whose molecular form is identical to that expressed in the secretory ameloblast. Electron microscopic immunocytochemitry revealed that sheath protein is contained in the Golgi apparatus located periodontal side of the epithelial cell rest of Malassez. Cement matrix itself did not contain sheath protein.2. Mesenchymal cells located near the surface of the root dentin expressed osteopontin, one of the marker of initial cementum, and have processes extending to the surface of the root dentin. Thses cells are usually attached to the epithelial cell rest of Malassez.3. After the administration of Monesin, one of the inhibitor of the cell secretory activity, osteopontin are clearly localized in the cytoplasmic processes extending from these mesenchynal cells.4. Expression of sheath protein was always prior to that of osteopontin.These results suggested that sheath protein secreted from the cells of Hertwig's epithelial root sheath and the epithelial cell rest of Malassez induced differentiation of mesenchymal cells to odontoblasts which extend cytoplasmmic processes to the surface of calcified dentin and form initial cement layer.

鞘蛋白（成釉细胞蛋白）是釉质基质蛋白的主要成分之一，不仅在分泌性成釉细胞中表达，而且在其他细胞类型中表达，例如未成熟的成牙本质细胞和马拉色上皮细胞其余部分。为了了解鞘蛋白在上皮-间质相互作用中的作用，我们试图证明鞘蛋白的表达与大鼠牙胚和门牙牙骨质形成早期阶段牙骨质分化的关系。研究结果如下： 1． Hertwig上皮根鞘的部分细胞和Malassez的上皮细胞其余部分表达鞘蛋白，其分子形式与分泌性成釉细胞中表达的鞘蛋白相同。电镜免疫细胞化学显示鞘蛋白包含在位于马拉塞上皮细胞其余部分牙周侧的高尔基体中。水泥基质本身不含鞘蛋白。2．位于牙根牙本质表面附近的间充质细胞表达骨桥蛋白，这是初始牙骨质的标志物之一，并且具有延伸至牙根牙本质表面的突起。这些细胞通常附着在 Malassez 的上皮细胞其余部分。3。给予细胞分泌活性抑制剂之一莫尼辛后，骨桥蛋白明显定位于从这些间充质细胞延伸的细胞质突起中。4．鞘蛋白的表达始终先于骨桥蛋白的表达。这些结果表明，Hertwig's上皮根鞘细胞和Malassez上皮细胞其余部分分泌的鞘蛋白诱导间充质细胞向成牙本质细胞分化，从而将细胞质过程延伸至钙化表面牙本质并形成初始水泥层。