Cadherins作为细胞粘附分子在神经系统中介导细胞粘附，影响神经细胞的分选、迁移、定位和轴突生长、路径选择等。我们的前期研究结果显示R-cadherin(Rcdh)在鸡胚脊髓发育中表达受腹背轴形成信号分子调控、抑制Rcdh表达导致神经细胞迁移紊乱、轴突生长和路径选择发生障碍，数字基因表达谱分析显示Rcdh与beta-catenin信号通路相关联。然而，Rcdh在脊髓发育中调控神经元迁移定位和轴突路径选择的作用和其是否参与脊髓至脑上行神经回路的形成还缺乏研究，其调控机制全然不知。据此，本研究将在发育脊髓中通过改变Rcdh表达，采用OpenBook、脊髓片和神经元分离培养以及实时观察等技术，从活体-组织-细胞不同层次研究Rcdh在神经元迁移定位、轴突生长和路径选择中的功能，并探索其发挥作用的分子机制。本项目的实施将揭示Rcdh在脊髓发育中的作用机理,为临床治疗相关神经系统疾病提供理论依据。

Cadherins, as cell adhesion molecules, mediate cell and cell adhesion, and further affect neural cell sorting, migration and localization, as well as axon growth and pathway finding. Our previous study showed that the spinal cord ventral and dorsal signal molecules regulate the expression of R-cadherin(Rcdh), Rcdh expression inhibition results in disorders of neuronal migration as well as axon growth and pathway finding during chicken embryonic spinal cord development. Digital gene expression profile analysis explored that Rcdh is related to beta-catenin signaling pathway. However, it is lack of study that how Rcdh regulates neuronal migration and localization, axon pathway finding, or if Rcdh is involved in the upstream neural circuit formation from the spinal cord to the brain, and its regulatory mechanisms are completely unaware. Accordingly, we will change the expression of Rcdh in the developing chicken spinal cord, use spinal cord OpenBook, spinal cord slice culture, neuron isoltion and culture, real-time observation, etc. to investigate the function of Rcdh on the neuronal migration and localization, and the axon growth and pathway finding, at three levels, living embryo - spinal cord slice - neuron, during the spinal cord development. Furthermore, we will explore the molecular mechanism of Rcdh function. This project will reveal functional mechanisms of Rcdh during the spinal cord development, and provide theoretical basis for the clinical treatment of Rcdh related nervous system diseases.

Cadherins作为细胞粘附分子在神经系统中介导细胞粘附，影响神经细胞的分选、迁移、定位和轴突生长、路径选择等。本课题通过分子克隆、原位杂交、免疫组化、细胞培养、活体电转基因、openbook、神经元分离培养、脊髓组织培养和神经纤维示踪等技术从活体-组织-细胞不同层次研究Rcdh及转录因子Pax3和Pax7在神经元迁移定位、轴突生长和路径选择中的功能，并探索其发挥作用的分子机制。进一步证实R-cadherin (Rcdh)在鸡胚脊髓发育中表达受腹背轴形成信号分子调控、抑制Rcdh表达导致神经细胞迁移紊乱、轴突生长和路径选择发生障碍。本研究分析了Rcdh在脊髓发育中调控神经元迁移定位和轴突路径选择的作用。首次发现：（1）转录因子Pax3和Pax7调控Rcdh的表达；（2）Pax3过表达抑制Pax7表达，但Pax7过表达诱导Pax3表达，说明二者存在反向调控关系；（3）Pax3和Pax7过表达强诱导Cadherin-7异位表达，但对Rcdh表达调控较弱；（4）Pax3和Pax7过表达促进了神经上皮细胞向神经细胞的分化过程，同时造成轴突生长及路径选择紊乱；（5）Rcdh过表达促进了神经细胞的聚集。上述结果部分证明了Rcdh在脊髓发育过程中的功能及调控，以及转录因子Pax3和Pax7对不同Cadherin表达与功能的影响，为进一步研究Cadherin和Pax3/Pax7在神经系统网络形成中的作用奠定了基础。