ENAMEL FLUOROSIS: MECHANISMS OF ACTION

描述：氟牙釉质症是暴露于过量氟化物后发生的牙釉质发育缺陷。氟牙釉质比健康牙釉质更多孔，并且含有更多的蛋白质。氟化物改变牙釉质形成的机制仍不清楚。在这种竞争性的更新，我们建议研究开始，以探索氟的间接影响所造成的变化，形成釉质基质，其次氟掺入釉质晶体的生长。我们还将继续探索氟对形成釉质的细胞、基质蛋白和蛋白酶的直接影响。我们假设氟化物对釉质形成的这两种影响是氟化物改变釉质形成的机制，并提出以下具体目标： 1）。确定氟化物对釉质形成和生物矿化的间接影响，包括釉质间隙的酸化，从而间接影响细胞和基质功能。 2）。目的：探讨氟离子与釉质蛋白质（包括釉原蛋白和蛋白酶）的相互作用对釉原蛋白加工和晶体生长的影响。 3)探讨氟对成釉细胞分化的直接影响，包括基质蛋白和蛋白酶表达的改变及细胞凋亡。 将测量氟化物暴露导致的pH变化，并在釉原蛋白敲除小鼠和HCO37C1（Ae2）交换敲除小鼠中确定釉原蛋白和碳酸氢盐缓冲在釉质基质和成釉细胞中的作用。将在体外晶体生长系统中测量氟化物与釉原蛋白和基质蛋白酶的直接相互作用以及对晶体生长的影响。我们将使用成釉细胞培养来鉴定与细胞增殖、凋亡相关的基因表达的氟相关变化，并测量与矿化相关的基质酶活性的变化。 这些研究对于了解氟中毒如何在牙釉质中形成具有重要意义。通过了解氟中毒发生的机制，我们将能够识别可能对氟更敏感或受氟影响的个体和条件，并能够更好地预防氟牙釉质症的形成。

DESCRIPTION: Enamel fluorosis is a defect in enamel development that occurs after exposure to excess fluoride. Fluorotic enamel is more porous, and contains more proteins than sound enamel. The mechanisms by which fluoride alters enamel formation remain not well understood. In this competing renewal, we propose studies to begin to explore the indirect effects of fluoride resulting from changes in the forming enamel matrix, secondary to fluoride incorporation in the growth of enamel crystals. We will also continue to explore the direct effects of fluoride on the cells, matrix proteins, and proteinases that form enamel. We hypothesize that both of these effects of fluoride on enamel formation are mechanisms by which fluoride alters enamel formation, and propose the following Specific Aims: 1). To determine the indirect effects of fluoride on enamel formation and biomineralization, including acidification of the enamel space that indirectly affects cell and matrix function. 2). To determine how fluoride interacts with enamel proteins including amelogenins and proteinases resulting in changes of amelogenin processing and crystal growth. 3) To determine how fluoride directly affects ameloblast differentiation, including altered expression of matrix proteins and proteinases, and apoptosis. The changes in pH resulting from fluoride exposure will be measured, and the effect of amelogenin and bicarbonate buffering in the enamel matrix and in the ameloblasts will be determined in amelogenin knockout mice and HCO37C1 (Ae2) exchange knockout mice. The direct interactions of fluoride with amelogenins and matrix proteinases, and the effect on crystal growth will be measured in an in vitro crystal growth system. We will use ameloblast cell culture to identify fluoride related changes in gene expression related to cell proliferation, apoptosis, and measure changes in activity of matrix enzymes that are related to mineralization. These studies are important to understand how fluorosis forms in enamel. By understanding the mechanisms by which fluorosis occurs, we will be able to identify individuals and conditions which may be more sensitive to or affected by fluoride, and will be better able to prevent the formation of enamel fluorosis.