Role of ameloblastin for ameloblasts and enamel formation

描述（由申请人提供）：NIDCR的指导临床科学家研究职业发展奖（K08）将为申请人提供成功的学术生涯和科学独立的牙科科学家培训。牙釉质的形成是人体最坚硬的生物矿物。牙釉质形成的紊乱导致牙釉质层发育不全或矿化程度低或遗传或环境原因。为了培养成为牙釉质病理生理学专家，提出了由教学课程和实验技术组成的培养计划。本实验计划旨在通过反馈机制研究釉质基质蛋白在成釉细胞分化和釉质形成中的作用。我之前对釉质基质成釉蛋白（Ambn）的研究已经确定了产生具有相反定位和相反命运的片段的主要切割位点。Ambn对牙釉质的形成至关重要，因为在缺乏Ambn的小鼠中牙釉质缺失，但当作为Ambn转基因提供时，牙釉质会以剂量依赖的方式恢复。这些发现导致了成釉细胞接受来自釉质基质的反馈信号来调节其功能和釉质矿化的假设。在Aim 1中，确定了Ambn在体内成釉细胞分化中的作用。在Aim 2中，Ambn切割的相关性是通过突变主要切割位点来确定的。在Aim 3中，探讨了通过去除牙釉质蛋白的潜在反馈机制。长期目标是了解牙釉质基质和成釉细胞之间的信号通路，为新的牙科诊断和治疗策略提供途径。这些针对牙釉质矿化的细胞机制的研究对日常牙科实践产生了影响。

DESCRIPTION (provided by applicant): The Mentored Clinical Scientist Research Career Development Award (K08) from NIDCR will provide the applicant with training for a successful, academic career and scientific independence as a dentist-scientist. Enamel formation results in the hardest biomineral of the human body. Disturbances of enamel formation result in a hypoplastic or hypomineralized enamel layer or inherited or environmental origin. To develop into an expert in enamel pathophysiology, a training plan consisting of didactic courses and experimental techniques is proposed. The experimental plan aims to study the role of enamel matrix proteins for ameloblast cell differentiation and enamel formation though feedback mechanism. My previous work on the enamel matrix protein ameloblastin (Ambn) has identified the major cleavage site that generates fragments with opposing localizations and opposing fates. Ambn is essential to proper enamel formation, as enamel is absent in mice null for Ambn, but is regained in a dose-dependent manner when supplied as an Ambn transgene. These findings lead to the hypothesis that ameloblasts receive feedback signal from the enamel matrix to regulate their function and enamel mineralization. In Aim 1 the role of Ambn in ameloblasts differentiation is defined in vivo. In Aim 2 the relevance of Ambn cleavage is determined by mutating the major cleavage site. In Aim 3 potential feedback mechanisms via removal of enamel proteins are explored. The long-term goal is to understand the signaling pathways between enamel matrix and ameloblasts as an approach to new diagnostic and therapeutic strategies in dentistry. These studies directed at cellular mechanisms for enamel mineralization have impact on the daily dental practice.