牙乳头细胞极性分化是其向成牙本质细胞转变的标志之一，也是成牙本质细胞发挥功能的最终状态，对牙髓损伤修复具有关键意义。然而，决定牙乳头细胞极性分化的关键基因尚不明确。课题组前期研究发现：Foxq1在成牙本质细胞中高表达；干扰Foxq1后牙乳头发育形成的成牙本质细胞层极性紊乱，牙本质发育异常；平面细胞极性通路蛋白Wnt5a可挽救Foxq1干扰后对牙胚的影响。本课题拟采用极性研究模型，明确Foxq1对牙乳头细胞极性分化的作用；构建Foxq/Wnt5a突变细胞株，利用免疫共沉淀和双荧光素酶实验剖析Foxq1对Wnt5a的相互作用方式及结合位点，探索Foxq1通过Wnt5a通路影响牙乳头细胞极性分化的分子机制及通路。本研究将以极性分化这一形态学角度为切入点，揭示Foxq1对牙本质发育的影响，阐明其对牙乳头细胞极性分化为成牙本质细胞的调控机制，为牙髓的损伤修复提供新的研究靶点。

Polarized differentiation of dental papilla cell is a key event in odontoblast differentiation. Polarization of odontoblast is also crucial for its proper function, which is important for dental pulp repairing. The key regulator for polarized differentiation of dental papilla cell, however, is still unclear. Result of our previous studies shown an increased expression of Foxq1 in odontoblast cell, while inhibition of Foxq1 could disrupt polarity in odontoblast layer and lead to abnormal development. We also found that wnt5a, a key factor in planar cell polarization pathway could salvage the influence on tooth germ caused by inhibition of Foxq1. The current study aim to achieve the following goals: firstly, establish cell polarization model and study Foxq1's effect on polarized differentiation of dental papilla cell; secondly, establish dental papilla cells with manipulated expression level of Foxq1 or Wnt5a, explore the relation between Foxq1 and Wnt5a with ChIP and dual luciferase assays, clarified the molecular pathway in which Foxq1 regulate polarized differentiation of dental papilla cell via regulating Wnt5a expression. Starting from Foxq1's involvement in dental papilla cell polarization, its influence on dentinogenesis and the underlying mechanisms will be studied, providing novel target for further study in dental pulp repairing.