Runx2在成牙本质细胞极化过程中作用机制的研究

Stem cell differentiate into matured odontoblast is an essential isuue in dental tissue engineering, where Runx2 plays a key role according to former researches. With differentiation and polarization of odontoblast changes, Runx2 signals is downregulated obviously. Odontoblasts of Runx2 overexpressing mice lost their cellular polarity and arrangement as a sheet of cells. Odontoblasts of Runx2 overexpressing mice lost their cellular polarity and arrangement as a sheet of cells. However, few research concerns on the role of polarization molecules in odontoblast differentiation and the regulation mechanism of that Runx2 influence the function..With Runx2 overexpressing mice model, this project explore the differential gene expression of polarity related molecules between the model and wild type mice in teeth morphology progress by some methods like immuno-electron microscopy. Some key molecules will be found after bioinformatics analysis. Applying EMSA,reporter gene, in vitro three-dimensional cell culture technique, the scheme how Runx2 control odontoblast polaritization through the target molecules will be clarified and verifies in two laser induced dental-pulp injury and wound healing mouse models. .This project aims at cell polarity, and contributes to clarifying the role of polarity related molecules in dental pulp stem cell differentiation and regulation mechanism, laying the fondation of further research about some key elements in DPSC(dental pulp stem cell) odontogenic differentiation, and initialing the reseach on dental tissue engineering and dental-pulp regeneration.

干细胞分化为成熟的成牙本质细胞是牙齿组织工程和牙髓损伤修复的核心问题，有报道和前期工作表明Runx2在其中起关键作用，成牙本质细胞分化成熟过程伴随着Runx2表达显著下调并发生极性化改变，Runx2过表达小鼠成牙本质细胞失去栅栏状排列和极性,而极化分子在成牙本质细胞分化中的作用及Runx2在其中的分子调控机制研究报道甚少。本项目利用课题组建立的Runx2过表达小鼠模型，采用免疫电镜等手段观察其与正常小鼠牙齿发育中极化分子表达差异，运用EMSA、报告基因、三维培养技术和激光诱导的两种可控牙髓损伤修复模型，结合生物信息学探寻参与极性化过程的关键分子并在体内外阐明Runx2通过其调控成牙本质细胞极化的分子机制。本研究首次围绕极性化的核心问题，探寻其在成牙本质细胞分化成熟中的作用和机制，为进一步探讨牙髓干细胞牙向分化的关键因素奠定理论基础，为牙齿组织工程和牙髓损伤修复研究和临床转化应用提供新的思路

研究背景：牙髓损伤的愈合过程包含一系列生物学和分子学的过程，包括细胞迁移、细胞粘附、细胞增殖、和细胞外基质的分泌。在损伤修复的过程中发挥关键作用的是牙髓干细胞，并且需要其最终分化成为具有极性的成牙本质细胞。为了对此过程进行初步的研究和探讨，我们选择了与细胞的极性化密切相关的极性分子作为研究对象，并通过细胞因子作为细胞极性化的诱导分子来诱导细胞极性的发生。.研究内容：1. 极性分子cdc42 在小鼠牙齿发育过程中的动态表达及相关研究；2. 极性分子cdc42在牙髓干细胞极性化迁移过程中的表达及影响；3. SDF-1诱导牙髓干细胞极性化迁移的机制分析.研究结果：1. Cdc42在牙齿发育的各个阶段都有明确的表达并参与成牙本质细胞对炎症的反应过程。2. cdc42的表达变化能够影响牙髓干细胞的极性化迁移。3.牙髓干细胞受到SDF-1的刺激后，能够通过极性分子进行信号传递并促使发生极性化的迁移。.研究结论：通过本课题的研究，我们确认了与细胞极性化密切相关的cdc42在成牙本质细胞发育过程中的表达，并通过敲除实验证实cdc42是牙髓干细胞极性化迁移必需的极性分子。同时，牙髓损伤过程中产生的sdf-1对牙髓干细胞的极性化迁移起到诱导的作用。