Enamel with overexpressed ameloblastin

项目概要/摘要 牙釉质的发育缺陷包括臼齿-切牙矿化不足（MIH）。这种情况会影响 牙釉质的质量和数量，严重破坏儿童的口腔功能， 敏感性和增加的龋齿易感性。患有MIH的儿童更需要牙科治疗 并且经常表现出牙齿行为管理问题。在许多情况下， 全球不同人群的患病率范围为2.4%至40.2%。釉质器官 上皮细胞受到未知因素的影响，导致MIH。MIH的病理生理机制尚不清楚。 治疗选择仅限于使用氟化物的常规治疗， 保留和提取差。釉质基质促进釉质形成为最硬的矿物 proteins.成釉蛋白（Ameloblastin，Ambn）是釉蛋白中的一种，占釉蛋白的5%。在 在低矿化的釉质中，矿物质含量达不到必要的浓度。Ambn是 在拔牙的低矿化牙釉质中发现，但尚不清楚它是否在牙釉质中起作用。 MIH的发病机制。我们已经开发了一种小鼠模型来研究Ambn过表达在小鼠中的作用。 成釉器上皮中的MIH样釉质。当Ambn过度表达时，这些小鼠的牙釉质 显示白色，分界线的“斑块”，容易从牙本质断裂。MIH小鼠模型将用于 剖析釉质矿化不足的细胞和分子事件，以确定 低矿化牙釉质的诊断、预防和治疗。 我们已经开发出转基因小鼠与划界，MIH样病变的牙釉质。我们的初步结果 显示病变随着成釉蛋白（Ambn）浓度增加而扩大。一般来说，牙釉质基质 被成釉细胞快速加工、降解和内化，但当Ambn过表达时， 釉质基质残留，矿物质的积累受到阻碍，表现为矿化不足 搪瓷。我们已经开发出工具，可以通过microCT准确量化矿物质含量和釉质体积 方法.在釉质基质的釉质器官上皮途径的转录组分析中，酶促 降解、蛋白质运输和离子处理失调。我们的总体假设是 成釉蛋白过表达影响釉质形成的机制，导致MIH病变， 搪瓷。在SA 1中，我们将确定牙釉质阶段性形成中界限浑浊的开始。 过表达Ambn的小鼠在SA 2中，我们将确定釉质内吞作用的生物学途径 蛋白质在体内和体外作为成釉蛋白过度表达的结果。在SA 3中，我们将确定是否 在Ambn小鼠中，过表达的Ambn的内吞作用可以通过增加 釉质基质对于拟议中的研究，一个由临床科学家、定量成像专家组成的团队， 蛋白质组学和生物信息学已被组装为独特的相互作用和新的方法。

PROJECT SUMMARY/ABSTRACT Developmental defects of enamel include molar-incisor hypomineralization (MIH). This condition affects the quality and quantity of enamel and severely disrupts oral functions in children with loss of occlusion, tooth sensitivity and increased caries susceptibility. Children with MIH have greater needs for dental treatment throughout their life and often exhibit dental behavioral management problems. MIH is found in many different populations worldwide with a prevalence ranging from 2.4% to 40.2%. The enamel organ epithelium is affected by unknown factors resulting in MIH. The pathophysiology of MIH is not understood. Therapeutic options are limited to conventional therapy with fluoride applications, restorations often with poor retention and extractions. Enamel formation into the hardest mineral is promoted by enamel matrix proteins. One of the enamel proteins is ameloblastin (Ambn) accounting for 5% of the enamel proteins. In hypomineralized enamel, the mineral content does not reach the necessary concentration. Ambn was identified in hypomineralized enamel of extracted teeth, but it is not clear if it plays a role in the pathogenesis of MIH. We have developed a mouse model to study the effect of Ambn overexpression in MIH-like enamel in enamel organ epithelium. When Ambn is overexpressed, the enamel in these mice displays white, demarcated ‘patches’ that fracture easily from the dentin. The MIH mouse model will serve to dissect the cellular and molecular events in enamel hypomineralization to identify strategies for the diagnosis, prevention and therapy of hypomineralized enamel. We have developed transgenic mice with demarcated, MIH-like lesions in enamel. Our preliminary results show that the lesions enlarge as the ameloblastin (Ambn) concentration increases. Normally, enamel matrix is rapidly processed, degraded and internalized by ameloblasts, but when Ambn is overexpressed, the enamel matrix lingers on and the accumulation of mineral is hampered, manifesting as hypomineralized enamel. We have developed tools to accurately quantify mineral content and enamel volume with microCT methods. In a transcriptome analysis of enamel organ epithelium pathways for enamel matrix, enzymatic degradation, protein trafficking and ion handling were dysregulated. Our overall hypothesis is that overexpressed ameloblastin influences the mechanisms of enamel formation resulting in MIH lesions in enamel. In SA1 we will determine the onset of demarcated opacities within the phased formation of enamel in mice overexpressing Ambn. In SA2, we will determine the biological pathways of endocytosis of enamel proteins in vivo and in vitro as a consequence of ameloblastin overexpression. In SA3, we will determine if endocytosis of overexpressed Ambn can be promoted in Ambn mice by increasing the enzymatic activity in the enamel matrix. For the proposed studies a team of clinician scientists, experts in quantitative imaging, proteomics and bioinformatics has been assembled for unique interaction and novel approaches.