Studies on functional roles of crystal-matrix protein interaction in developmental enamel mineralization

牙釉质形成是一个复杂的生物矿化过程，它包括时空协调的事件，例如，通过连续的上皮-间充质相互作用的细胞增殖和分化、组织特异性基质蛋白的分泌和它们在细胞外空间中的寡聚分子结构的构建、以及通过有机和无机分子之间的多重相互作用的体内最大的碳磷灰石的沉淀/生长和三维定向排列。与牙本质发生和骨发生相比，釉质形成的特征在于几个独特的特征：（a）大多数分泌的蛋白质被多种蛋白酶原位降解并从组织中去除，（B）釉质晶体的生长在所有发育阶段中逐渐进行，和（c）矿化过程不受形成的组织的任何重塑的干扰。这些独特的生物资本化过程是前 ...更多信息 切割，至少部分取决于细胞对物质运输的严格调节，例如，普通离子（例如，Ca 2+和磷酸盐）和杂质（例如，碳酸盐）从血液循环进入细胞外空间。为了研究生物矿化的调节机制，我们在当前阶段的工作重点是通过修改商业上可获得的透析室来开发实验沉淀模型。在设计实验装置时，我们考虑到的关键因素是：（a）利用过饱和溶液作为原位液相，（B）用分泌性釉质中发现的釉质蛋白涂覆磷灰石种子，和（c）限制Ca供应到种子晶体周围的介质中，如先前放射自显影工作所假设的原位。所获得的结果支持的假设，即在钙供应的情况下，在整个过程中成为一个速率detormining步骤，（i）相对于常见离子的稳态条件是可实现的矿化环境和（ii）所得到的液体组合物依赖于在一个敏感的方式对磷灰石沉淀，即，釉质蛋白和F-的调节剂的存在。特别是，在有关了解的发病机制的氟牙釉质症，这是现在的特点是组织成熟的延迟所造成的过量纳入氟到细胞外环境，目前的工作提供了证据，氟对钙浓度的影响，在矿化环境。少

Enamel formation is a complex biomineralization process, which comprises temporo-spatially orchestrated events, e.g., cellular proliferation and differentiation through the sequential epithelial-mesenchymal interactions, secretion of the tissue-specific matrix proteins and construction of their oligomeric molecular structures in the extracellular space, and precipitation/growth and three-dimonsionally oriented alignment of the largest carbonatoapatites in the body through the multiple interactions between organic and inorganic molecules. In comparison with dentinogenesis and osteogenesis, enamel formation is characterized by several unique features : (a) most of the secreted proteins are degraded in situ by multiple proteases and are removed from the tissue, (b) the growth of enamel crystals proceeds gradually through all the developmental stages, and (c) the mineralization process is not intervened by any remodeling of the formed tissue. These unique biominoralization processes are ex … More ecuted, at least in part depending on the tight cellular regulation of mass transport, e.g., transport of common ions (e.g, , Ca^<2+> and phosphate) and impurities (e.g., carbonate) from blood circulation into the extracellular space. In order to investinate the regulatory mechanism of biomineralization, our effort during the current period was focused on development of an experimental precipitation model by modifying a commercially available dialysis chamber. In designing the experimental apparatus, key considerations we took into account are : (a) utilizing a supersaturated solution as prodicted in in situ fluid phase, (b) coating apatite seeds with enamel proteins as found in the secretory enamel, and (c) limiting Ca supply into media surrounding the seed crystals as supposed in situ by previous autoradiographic work. The results obtained support the hypothesis that, under the situation where Ca supply becomes a rate-detormining step in the whole process, (i) the steady state condition with respect to the common ions is achievable in the mineralizing milieu and (ii) the resulting liquid composition depends in a sensitive manner on the presence of regulators for apatite precipitation, namely, enamel proteins and F-. Particularly, in relation to understanding of the pathogenosis of enamel fluorosis, which is now characterized by the delay of tissue maturation caused by excess incorporation of fluoride into the extracellular environment, the current work provided evidence for the effects of fluoride on Ca concentration in the mineralizing milieu. Less