Rheb-mTOR信号通路启动细胞周期在神经炎症中的意义

Cell cycle re-entry causes neuronal apoptosis and astrocytic activation induced by neuroinflammation. Activation of the Rheb-mTOR signal pathway can promote cell cycle procession in tumor cells. Our previous study has found that the Rheb-mTOR signal pathway plays an important role in neuroinflammation. Therefore, we hypothesized that the Rheb-mTOR signal pathway participates in neuronal apoptosis and astrocytic activation induced by neuroinflammation via cell cycle re-entry. In this study, we will first analyze the connection between the Rheb-mTOR signal pathway and cell cycle by detecting the time-space expression of molecules in the Rheb-mTOR signal pathway; then, analyze the relationship upon by intervening the Rheb-mTOR signal pathway in the cell model of astrocytic activation induced by LPS and neuronal apoptosis induced by conditional medium, respectively; finally, to intervene the Rheb-mTOR signal pathway at gene and medicine levels, the common animal model of neuroinflammation- LPS injection of lateral ventricle was established. We aim to clarify the molecular mechanisms among the three above mentioned in neuroinflammation, which might provide a new sight for the prevention and treatment of neurologic diseases.

细胞周期启动参与神经炎症诱导的星形胶质细胞活化和神经元凋亡。肿瘤细胞中Rheb-mTOR信号通路的激活可以促进细胞周期启动。课题组前期研究发现：Rheb-mTOR信号通路在神经炎症中发挥重要作用，因此提出Rheb-mTOR信号通路通过激活细胞周期参与神经炎症诱导的星形胶质细胞活化和神经元凋亡的假说。课题组拟首先在神经炎症模型中分析Rheb-mTOR信号通路相关分子的时空表达变化及与细胞周期的相关性；接着分别在LPS刺激星形胶质细胞炎性模型及条件培养基刺激神经元凋亡模型中干预Rheb-mTOR信号通路，分析其与细胞周期相关分子的相关性及对星形胶质细胞激活与神经元凋亡的影响；最后在整体神经炎症模型中在基因或药物水平干预Rheb-mTOR信号通路，阐明上述三者间的相互调节关系，藉此为临床上CNS疾病的预防和治疗提供新的视角。

神经炎症的病理生理机制主要为星形胶质细胞增生和神经元凋亡；Rheb-mTOR信号通路在介导细胞增殖、凋亡过程中发挥重要作用。本研究从Rheb-mTOR信号通路与细胞周期启动相关蛋白相互作用的角度探究其在神经炎症中的作用。本研究首先通过蛋白质印迹法和免疫组织化学染色法在大鼠侧脑室注射LPS的神经炎症模型中检测到Rheb在大鼠大脑皮层中表达上调。免疫荧光染色证实Rheb主要定位于活化的星形胶质细胞及神经元。同时细胞增殖标记物PCNA及细胞凋亡标记物活化的caspase-3与Rheb有共定位，提示Rheb参与星形胶质细胞活化及神经元凋亡。此外，细胞周期启动相关蛋白cyclinD1和CDK4与Rheb存在时空定位。最后，通过siRNA敲低Rheb表达及药物雷帕霉素或洛伐沙汀阻断Rheb-mTOR通路后出现星形胶质细胞增殖被减弱和保护神经元保护现象。综上所述，本研究首次发现了Rheb-mTOR信号通路与细胞周期启动蛋白相互作用，并促进神经炎症中星形胶质细胞增殖和神经元凋亡的生物学功能。该研究为深入理解神经炎症疾病提供了新的线索，对于进一步揭示Rheb-mTOR的生物学功能具有重要的科学意义。