DSPP signaling in dentinogenesis

项目摘要 牙科和NIDCR/NIH最重要的目标之一是生成一个完整的“生物- 牙”。牙本质是牙齿的重要组成部分。虽然它已经取得了很大的进步， 牙本质发育有益于许多遗传综合征和染色体异常， 仍然存在许多差距。了解牙齿间充质细胞的信号通路 谱系和牙本质的形成将为牙本质的修复和再生提供途径。 牙本质涎磷蛋白（Dspp）在成牙本质细胞和牙本质中高度表达， 牙本质涎蛋白（Dsp）和牙本质磷蛋白（Dpp）。Dsp和Dpp突变是 与牙本质发育不全（DGI）相关，这是最常见的牙本质遗传病 disorder. 我们的长期目标是阐明控制牙本质形成的生物学机制， 将填补导致牙本质再生的知识空白。这里的目标是定义 信号通路对牙本质形成至关重要。我们的中心假设是， Bmp 2-pAkt-pErk-Dlx 3-Sp 7-Gcn 5-Dspp之间的几种信号以及 Dsp-整合素β6和Dsp-封闭素在牙本质形成中起协同作用。的 假设是基于我们使用全局敲除（KO）和 条件性KO（cKO）小鼠模型以及体外细胞和分子方法。三 具体目的是提出来检验这一假设：1）。为了确定Dspp中的Bmp 2信号传导， 表达和牙本质形成。Bmp 2信号发挥功能作用：Dspp表达通过上调- Bmp 2-pAkt-Erk-Dlx 3-Sp 7-Gcn 5G信号通路的调节。2）。挽救牙本质的形成， 通过过表达Dspp基因的Bmp 2 KO小鼠。由于Dspp表达显著降低， 和牙本质缺陷，假设在Bmp 2 KO小鼠中Dspp过表达 能够挽救牙本质的形成。3）。为了确定Dsp信号在牙间充质细胞中的作用， 分化和牙本质形成。Dsp被MMP 9处理成活性片段，作为 配体与细胞膜受体、整联蛋白β6和闭合蛋白结合。Dsp-β6复合物呈阳性 通过上调Smad 1/5/8刺激Dspp表达和成牙本质细胞稳态 发信号。Dsp-闭合蛋白信号增强粘着斑激酶（FAK）的磷酸化， 促进牙齿间充质细胞分化。这项研究具有创新性，因为 Dsp/Dspp的转录、翻译后加工和信号转导的每一步都是 这是形成健康牙本质所必需的。这些知识将促进我们对 遗传性疾病的发病机制，威胁牙本质的结构完整性，并提供了一个 治疗牙病和牙本质再生的潜在线索。

Project summary One of the most important goals of dentistry and the NIDCR/NIH is to generate a whole “Bio- Tooth”. Dentin is a critical structural component of tooth. Although it has made great progress of dentin development benefit for numerous hereditary syndromes and chromosomal anomalies, many gaps have been remained. Understanding signaling pathways of dental mesenchymal lineages and dentin formation would provide an avenue for repair and regeneration of dentin. Dentin sialophosphoprotein (Dspp) is highly expressed in odontoblasts and dentin and processed in to dentin sialoprotein (Dsp) and dentin phosphoprotein (Dpp). Dsp and Dpp mutations are associated with dentinogenesis imperfecta (DGI), which is the most common dentin genetic disorder. Our long-ranged goal is to elucidate the biological mechanisms controlling dentin formation, which will fill a key gap of knowledge leading to dentin regenerating. The objective here is to define the signaling pathways essential for dentinogenesis. Our central hypothesis is that the novel control mechanisms, in which the several signals among Bmp2-pAkt-pErk-Dlx3-Sp7-Gcn5-Dspp as well as Dsp-integrin β6 and Dsp-occludin play synergic roles in controlling dentin formation. The hypothesis is based on our strong preliminary data produced using both global knockout (KO) and conditional KO (cKO) mouse models as well as in vitro cellular and molecule approaches. Three Specific Aims are proposed to test this hypothesis: 1). to determine Bmp2 signaling in Dspp expression and dentin formation. Bmp2 signal plays functional roles: Dspp expression via up- regulation of Bmp2-pAkt-Erk-Dlx3-Sp7-Gcn5G signaling pathways. 2). to rescue dentin formation in Bmp2 KO mice by overexpression of Dspp gene. Due to dramatically decrease of Dspp expression and dentin defect in Bmp2 KO mice, the hypothesis is that Dspp overexpression in Bmp2 KO mice is able to rescue dentin formation. 3). to determine Dsp signaling in dental mesenchymal cell differentiation and dentin formation. Dsp is processed by MMP9 into active fragments, which as ligands bind to cell membrane receptors, integrin β6 and occludin. The Dsp-β6 complex positively stimulates Dspp expression and odontoblast homeostasis through up-regulation of Smad1/5/8 signaling. Dsp-occludin signal enhances phosphorylation of focal adhesion kinase (FAK), promoting dental mesenchymal cell differentiation. The proposed research is innovative because each step of transcription, posttranslational processing and signaling transduction of Dsp/Dspp is necessary for the formation of healthy dentin. Such knowledge will advance our understanding of the pathogenesis of inherited disorders that threaten the structural integrity of dentin and provide a potential clue for treating dental diseases and dentin regeneration.