DSPP signaling in dentinogenesis

项目总结 牙科和NIDCR/NIH最重要的目标之一是产生一个完整的“生物-- 牙齿“。牙本质是牙齿的重要结构成分。虽然它已经取得了很大的进步 牙本质发育有利于许多遗传性综合征和染色体异常， 许多差距仍然存在。了解牙间充质的信号转导途径 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表达 包括牙本质唾液蛋白(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，DGI是最常见的牙本质遗传 无序。 我们的长期目标是阐明控制牙本质形成的生物学机制，即 将填补导致牙本质再生的关键知识空白。这里的目标是定义 牙本质形成所必需的信号通路。我们的中心假设是，新的控制 其中BMP2-pakt-perk-DLX3-SP7-Gcn5-Dspp之间的几种信号以及 数字信号处理器-整合素β-6和数字信号处理器-闭锁蛋白在牙本质形成过程中发挥协同作用。这个 假设基于我们使用全局基因敲除(KO)和 条件性KO(CKO)小鼠模型以及体外细胞和分子方法。三 提出了检验这一假说的具体目标：1)。确定DSPP中的BMP2信令 表达和牙本质形成。BMP2信号发挥功能：Dspp通过Up-2表达 BMP2-PACK-ERK-DLX3-SP7-Gcn5G信号通路的调控。2)。挽救牙本质形成 Dspp基因过表达的BMP2KO小鼠。由于Dspp表达大幅下降 和BMP2 KO小鼠的牙本质缺陷，假说是Dspp在BMP2 KO小鼠中过表达 能够挽救牙本质的形成。3)。牙本质间充质细胞中DSP信号的检测 分化和牙本质形成。MMP9将DSP处理成活性片段，作为 配体与细胞膜受体、整合素β6和阻滞素结合。数字信号处理器-β-6络合物的正性 上调Smad1/5/8促进DSPP表达和成牙本质细胞动态平衡 发信号。DSP-occludin信号增强粘着斑激酶(FAK)的磷酸化， 促进牙间充质细胞分化。这项拟议的研究具有创新性，因为 DSP/DSPP的转录、翻译后处理和信号转导的每个步骤都是 是形成健康牙本质所必需的。这样的知识将促进我们对 遗传性疾病的发病机制威胁到牙本质的结构完整性，并提供 治疗牙科疾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.