Characterization of sodium dependent phosphate transporter 2 signaling in hard tissue mineralization

项目摘要 骨骼的生长和体内平衡需要钙和无机磷（Pi）。数百万美国人 患有骨矿化障碍，需要了解控制硬组织的过程。 组织矿化Pi不仅参与形成羟基磷灰石，这是赋予骨骼其 抗压强度，而且还调节成骨细胞和软骨细胞的分化和功能。PiT-2（基因： Slc 20 a2）是矿化组织中钠依赖性Pi转运蛋白的主要形式。我们的实验室是 这是第一个发现它在调节骨骼发育和矿化中的有效作用的人。敲除 PiT-2基因在小鼠中导致牙齿和骨矿化异常，如成骨细胞减少所证明的 数量，骨密度和体积，以及受损的切牙发育和釉质形成。的重点 研究旨在进一步探索PiT-2在控制骨骼发生的细胞和细胞外过程中的作用， 牙本质形成和釉质形成。具体而言，目标1将确认并扩展我们的初步研究结果， 确定PiT-2是否是调节成牙本质细胞和成釉细胞数量、分化和/或 矿化活性缺乏导致牙本质形成和釉质形成受损。PiT-2的作用 还将使用磨牙损伤小鼠模型研究牙本质修复和三级牙本质形成。具体目标 2，我们将以成骨细胞为例，明确PiT-2在矿化细胞中的作用机制。的Pi PiT-2的转运和传感/信号传导功能将通过工程化的PiT-2转运缺陷来剖析。 变种人我们希望这些研究能够更好地了解Pi如何影响硬组织的功能 形成细胞，作为基础开发新的治疗方法，用于患有矿化的患者 疾病，如骨质疏松症和骨质减少症。该项目将在华盛顿大学进行， 生物工程和口腔健康科学部门之间的合作在DDS-博士培训 的PI。PI将培养批判性思维技能，学习最先进的细胞和分子技术， 体内转基因小鼠模型和数据分析，这将为他的独立研究做好准备。最终将其识别为 强大的导师团队，多学科的合作努力，以及华盛顿大学的资源， 通过该奖项的支持将为学员未来的终身教职职位做好准备， 生物矿化过程

Project Summary Growth and homeostasis of bones require calcium and inorganic phosphorus (Pi). With millions of Americans suffering from bone mineralization disorders, there exists a need for understanding processes governing hard tissue mineralization. Pi is implicated in not only forming hydroxyapatite, the main crystal giving bone its compressive strength, but also regulating osteoblast and chondrocyte differentiation and function. PiT-2 (gene: Slc20a2) is the major form of sodium-dependent Pi transporters in mineralized tissue. Our laboratory is one of the first to have identified its potent role in regulating skeleton development and mineralization. Knockout of the PiT-2 gene in mice resulted in tooth and bone mineralization abnormalities, as evidenced by reduced osteoblast numbers, bone density and volume, and impaired incisor development and amelogenesis. The focus of this research is to explore further the role of PiT-2 in cellular and extracellular processes governing skeletogenesis, dentinogenesis, and amelogenesis. Specifically, Aim 1 will confirm and extend our preliminary findings to determine whether PiT-2 is required for regulation of odontoblast and ameloblast numbers, differentiation, and/or mineralizing activity with deficiencies leading to impaired dentinogenesis and amelogenesis. A role of PiT-2 in dentin repair and tertiary dentin formation will also be studied using a molar injury mouse model. In Specific Aim 2, we will define the mechanisms of action of PiT-2 in mineralizing cells using osteoblasts as an example. A Pi transport and sensing/signaling function of PiT-2 will be dissected through engineered PiT-2 transport deficient mutants. We expect these studies to provide a better understanding of how Pi influences functions of hard tissue forming cells, serving as a basis to develop novel therapeutics for patients suffering from mineralization disorders, such as osteoporosis and osteopenia. This project will take place at the University of Washington with collaborations between the Departments of Bioengineering and Oral Health Sciences during DDS-PhD training of the PI. The PI will develop critical thinking skills, learn state-of-the-art cellular and molecular techniques, in vivo transgenic mouse models, and data analysis that will prepare him for independent research. Ultimately, a strong mentorship team, multidisciplinary collaborative effort, and resources at the University of Washington with support through this award will prepare the trainee for a future tenure-track faculty position to study biomineralization processes.