CELL AND GENETIC APPROACHES TO ENAMEL BIOMIMETICS

牙齿是组织复合体，其中每个组织产生独特的 其蛋白质成分指导生物矿化的基质。 的 牙齿的外覆层是高度有序的非细胞生物陶瓷 叫做搪瓷。 牙釉质是建立在牙本质上的，类似但独特 从骨头。 我们预测，牙齿的分级基因表达， 蛋白质导致结构层次。 在本申请中，我们 将获得所需的牙釉质结构层次的信息， 产生釉质仿生物。 蛋白质模板指导 无机相将在体外使用重组产生的 釉质蛋白质。 牙釉质和牙本质之间的独特界面， 牙本质釉质连接（DEJ）在牙本质的形成中起着关键作用。 牙齿的生物力学功能。 目前， 关于DEJ发展的信息， 这些蛋白质的形成和组织产生了一种 这种不同生物力学的材料之间的界面 特性. 为了生产釉质仿生物， 概括一下DEJ。 我们将检验DEJ的形成 依赖于特定基因的表达， 在界面处经历混合的结构蛋白， 在界面处的混合物，这种混合物是必不可少的结合 牙釉质到牙本质 我们将调制DEJ界面和体 在转基因动物中使用组织特异性启动子 在DEJ和釉质内表达选定的蛋白质。 的 将使用靶基因缺失的互补方法， 消除选定的结构蛋白的贡献。 基因 将建立稳定的小鼠品系， 形态和结构特征。 第一代珐琅 组织替代品，与DEJ完成，将使用 永生的成釉细胞样细胞组织成一个组织样的三个 三维支架产生具有DEJ的完整的釉质仿生。 与贝尔博士和萨里卡亚博士的合作研究将确定 对照小鼠牙齿的生物力学性能以及 ~获得或丧失功能~小鼠。 提出了四个具体目标： 确定选定的牙齿特异性蛋白质对牙齿生长的影响。 体外矿物质沉积和组成; 2）使用转基因 动物作为获得功能测试的一部分，确定 牙齿上过量的选定牙齿特异性蛋白质 体内生物矿化; 3）改变牙本质釉质连接和/或 使用同源重组来减少或消除 作为功能丧失测试的一部分的体内牙齿特异性蛋白; 4） 通过提供三维框架来生产人造牙釉质 用于在重构的控制下釉质生物矿化 釉器上皮 这些实验，加上合作 与华盛顿大学材料科学家的互动， 凯斯西储大学将使一个合理的设计， 人牙釉质仿生装置

Teeth are tissue composites in which each tissue produces a unique matrix whose protein component(s) direct biomineralization. The outer covering of teeth is a highly ordered, acellular bioceramic called enamel. Enamel is built upon dentin, similar but distinctive from bone. We predict that hierarchical gene expression for dental proteins results in a structural hierarchy. In this application we will acquire information about enamel structural hierarchy needed to produce an enamel biomimetic. The protein template directing the inorganic phase will be analyzed in vitro using recombinant produced an enamel proteins. The unique interface between enamel and dentin, the dentin enamel junction (DEJ), plays a critical role in the biomechanical function of the tooth. Presently there is a paucity of information about DEJ development, the proteins contributing to formation and the organization of these proteins yielding an interface between materials of such dissimilar biomechanical properties. To produce an enamel biomimetic requires the ability to recapitulate the DEJ. We will test the hypothesis that DEJ formation is dependent upon the expression of specific genes encoding structural proteins that undergo admixture at the interface and this mixture at the interface and this mixture is essential to bonding enamel to dentin. We will modulate the DEJ interface and the bulk enamel in transgenic animal using tissue specific promoters to express selected protein at the DEJ and within enamel. The complementary approach of targeted gene deletion will be used to ablate the contribution of selected structural proteins. Genetically stable lines of mice will be created whose teeth will reflect novel morphologic and structural features. A first generation enamel tissue replacement, complete with DEJ, will be produced using immortal ameloblast-like cells organized into a tissue-like three dimensional scaffold yielding an enamel biomimetic complete wit DEJ. Collaborative research with Dr. Baer and Dr. Sarikaya will identify biomechanical properties of teeth from control mice as well as from ~gain or loss of function~ mice. Four specific aims are proposed: 1) Determine the effect(s) of selected tooth specific proteins on mineral deposition and composition in vitro; 2) Using transgenic animals as part of a gain of function test, determine the effects of excessive amounts of selected tooth specific proteins on tooth biomineralization in vivo; 3) Alter the dentin enamel junction and/or bulk enamel using homologous recombination to reduce or eliminate a tooth specific protein in vivo as part of a loss of function test; 4) Produce artificial enamel by providing a three-dimensional framework for enamel biomineralization under the control of reconstituted enamel organ epithelia. These experiments, coupled to collaborative interactions with material scientist at University of Washington and Case Western Reserve University will enable a rational design for a human enamel biomimetic device.