Effect of Fluoride on Cell Signaling in Amelogenesis

氟化物对釉质生成中细胞信号传导的影响

• 批准号: 7118635
• 负责人: TRACIE L FERREIRA
• 金额: $ 7.26万
• 依托单位: UNIVERSITY OF MASSACHUSETTS DARTMOUTH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7118635
• 关键词: ameloblasts; apoptosis; biological signal transduction; dental development; developmental genetics; fluoride ion; gene expression; genetically modified animals; growth factor receptors; in situ hybridization; laser capture microdissection; light microscopy; microarray technology; odontoblasts; polymerase chain reaction; scanning electron microscopy; transforming growth factors; transmission electron microscopy; zebrafish

Enamel is the hardest substance in the human body. Fluoride is commonly used in caries prevention, but high levels of fluoride result in fluorosis and enamel defects. Over several decades researchers have defined the biochemical and structural biology behind fluorotic enamel, however, a gap exists in relating these changes to the molecular signaling events that direct amelogenesis. The goal of these studies is to identify signaling pathways that are altered upon exposure to fluoride thereby resulting in amelognesis defects using a novel fluorosis model: the zebrafish. The zebrafish offers a unique opportunity to answer some of the molecular signaling questions relevant to the mechanism of human fluorosis because they mature rapidly, replace their teeth continuously and possess many of the same signaling pathways as described for human tooth development. Zebrafish teeth display similar fluorotic defects to those seen in mammals and compositional analysis reveals that zebrafish fluorosis is concomitant with decreased mineral content, and increased protein levels similar to that seen in humans. Furthermore, the elevated level of apoptosis in the tooth buds of the fluoride treated animals, correspond with altered cell signaling events indicated by decreased TGF-beta signaling pathway components. Specific Aim 1 will utilize microarray technology to identify genes whose expression is altered in fluorotic teeth. Specific Aim 2 will localize the changes in gene expression in subpopulations of tooth bud cells using laser microdissection and Real Time- PCR. Specific Aim 3 will further characterize the structural changes in fluorotic zebrafish enameloid. Our hypothesis is that fluoride alters growth factor receptor signaling, which perturbs ameloblast activities, resulting in increased programmed cell death and defective mineralization of the enameloid-matrix. The studies performed in this work will provide a foundation for our long-term goals, which include analysis of molecular signaling events regulating enamel formation in mammals.

搪瓷是人体中最难的物质。氟化物通常用于预防龋齿，但高水平的氟化物会导致氟中毒和搪瓷缺陷。数十年来，研究人员已经定义了荧光搪瓷背后的生化和结构生物学，但是，将这些变化与直接降解的分子信号事件联系起来存在差距。这些研究的目的是鉴定暴露于氟化物后改变的信号通路，从而使用新型的氟中毒模型：斑马鱼。斑马鱼提供了一个独特的机会，可以回答与人类氟中毒机制相关的某些分子信号问题，因为它们迅速成熟，连续更换牙齿，并具有与人牙齿发育所描述的许多相同的信号通路。斑马鱼的牙齿与哺乳动物中发现的荧光缺陷相似，成分分析表明斑马鱼氟中毒与矿物质含量的降低相关，并且蛋白质水平与人类相似。此外，氟化物处理动物的牙齿芽中凋亡水平升高，与TGF-β信号通路途径降低所指示的细胞信号事件相对应。 特定的目标1将利用微阵列技术来识别其表达在荧光牙齿中改变的基因。特定的目标2将使用激光显微解剖和实时P​​CR将基因表达的变化定位在牙齿芽细胞亚群中。具体的目标3将进一步表征荧光斑马鱼磁蛋白酶的结构变化。我们的假设是，氟化物改变了生长因子受体信号传导，这种传导会导致蛋白细胞活性，从而导致编程细胞死亡增加和搪瓷 - 基质的矿化缺陷。在这项工作中进行的研究将为我们的长期目标提供基础，其中包括对调节哺乳动物牙釉质形成的分子信号事件的分析。