从海马-杏仁核神经元PI3K/Akt/mTOR信号通路与细胞骨架关系探讨抑郁症发病机制

Depression is one of the most typical stress disorders, and has progressively increased incidence, but its pathogenesis has not been clarified yet. It has been documented that significant reduced of hippocampus and amygdala volumes, one symptom of this disease, may be due to the enhanced neuronal apopotosis of these parts. It's well known that PI3K/Akt/mTOR signal pathway is one of the important ways to adjust apoptosis, and cytoskeleton is the foundation of cellular structure and function. Then we speculate that the cytoskeletonal changes of neuron in hippocampus and amygdala may be adjusted by PI3K/Akt/mTOR signal pathway. In this research, we will establish depression rat model by giving rats chronic unpredictable mild stress (CUMS), and observe the neuronal ultrastructure by using transmission electron microscope, detect the relationship between the cytoskeletonal changes and PI3K/Akt/mTOR signal pathway using immunohistochemistry, confocal laser scanning microscope (CLSM), Western-blotting and fluorescence in situ hybridization. In order to explore the role of PTEN, a key gene regulating cell proliferation and apoptosis, in this process, we attempt to construct the virus over-expressing PTEN, and transfect it to depression rat, and observe the effect of PTEN over-expression on cytoskeletion and signal pathway. Investigating the role of PTEN on neuronal cytoskeletion and signal pathway in this project, may help to provide experimental evidence for the pathogenesis of depression.

抑郁症发病率越来越高，已成为目前一个研究热点，但其具体发病机制尚未明确。研究提示海马和杏仁核体积结构异常是抑郁患者的典型症状之一，其原因可能与这些部位存在明显的神经细胞凋亡有关。PI3K/Akt/mTOR信号通路是调节凋亡的重要途径之一，细胞骨架是细胞功能和结构的基础，因此我们推测在抑郁症发病中海马、杏仁核神经元细胞骨架改变受PI3K/Akt/mTOR信号通路调控。本研究利用慢性不可预见性温和应激建立大鼠抑郁症模型，采用透射电镜等技术观察海马、杏仁核神经元超微结构变化；采用免疫组织化学、激光扫描共聚焦、免疫印迹及荧光原位杂交等技术检测海马、杏仁核神经元细胞骨架和PI3K/Akt/mTOR信号通路改变的关系。同时构建PTEN腺病毒，活体转染至抑郁症动物模型，观察过表达PTEN基因对细胞骨架和信号通路的影响，从而为揭示抑郁症发病过程中海马和杏仁核的结构变化及抑郁症发病机制研究提供实验依据。

抑郁症具体发病机制尚未明确。海马和杏仁核体积结构异常是抑郁患者的典型症状之一，其原因可能与这些部位存在明显的神经细胞凋亡有关。PI3K/Akt/mTOR信号通路是调节凋亡的重要途径之一，细胞骨架是细胞功能和结构的基础。为检测抑郁症发病中海马、杏仁核细胞骨架改变及PI3K/Akt/mTOR信号通路调节作用，本研究利用慢性不可预见性温和应激建立大鼠抑郁症模型，观察海马、杏仁核神经元凋亡、自噬现象和神经元形态结构的改变；定量检测海马、杏仁核神经元细胞骨架蛋白和PI3K/Akt/mTOR信号通路的改变，以及PI3K/Akt/mTOR信号通路对细胞骨架蛋白表达的关系。同时构建PTEN腺病毒，活体转染至抑郁症动物模型，观察过表达PTEN基因对细胞骨架和信号通路的影响。研究结果表明，（1）CUMS能够使大鼠表现出典型的抑郁症症状；（2）抑郁症大鼠海马、杏仁核部位存在明显的神经元凋亡，自噬也增强，凋亡相关蛋白和自噬相关蛋白表达均增高，电镜下有明显的形态结构改变；（3）抑郁症发生过程中海马、杏仁核神经元主要细胞骨架蛋白MAP、Tau表达异常，呈现出磷酸化程度先降低后逐渐增高的趋势，并且有共定位；（4）抑郁症海马、杏仁核神经元PI3K/Akt/mTOR信号通路关键蛋白PTEN、p-Akt、p-mTOR磷酸化降低；（5）转染PTEN后，PI3K/Akt/mTOR信号通路主要蛋白p-Akt和p-mTOR表达进一步降低。本项目结果从形态学和分子水平探讨了抑郁症海马、杏仁核结构改变的原因，阐述抑郁症发病过程中海马、杏仁核神经细胞PI3K/Akt/mTOR信号通路和细胞骨架改变的关系，揭示PTEN基因在海马和杏仁核中对PI3K/Akt/mTOR信号通路的调节作用以及对细胞骨架的影响，为揭示抑郁症发病过程中海马和杏仁核的结构变化及抑郁症发病机制研究提供实验依据。.项目共发表论文27篇，其中SCI收录3篇，核心期刊17篇。培养研究生4名，获得市级以上奖励2项。