TREM2/DAP12信号通路调控神经胶质细胞表型转变及交互作用在运动训练改善脑卒中后认知障碍中的作用机制

White matter damage has received great attention for its roles in the development of post-stroke cognitive impairment (PSCI). The phenotype transformation and crosstalk of microglia and astrocyte are crucial for white matter damage and repair, The TREM2/DAP12 pathway regulates the response of both glial cells. It is demonstrated that physical exercise could improve PSCI, but the underlying mechanism is unclear. We found that physical exercise can promote the transformation of microglia to neuroprotective phenotype and the repair of white matter damage, then improve the cognitive impairment of chronic cerebral ischemia. Our preliminary experiment showed that physical exercise can also promote the transformation of astrocyte to neuroprotective phenotype and increase the expression of TREM2 in the brain of rats with cerebral infarction. We hypothesized that physical exercise could promote the neuroprotective phenotype transformation and crosstalk of microglia and astrocyte by activating the TREM2/DAP12 pathway, thereby promoting the improvement of white matter damage and PSCI. The physical exercise intervention model of transient focal cerebral ischemia by left transient middle cerebral artery occlusion are used in this experiment, the proteomics, immunoelectron microscopy and other methods were used to explore whether physical exercise can improve PSCI through regulating the phenotype transformation and crosstalk of neuroglia cell, and clarify the role of TREM2/DAP12 pathway, the results will provide experimental evidence for understanding the mechanism of PSCI and optimizing its intervention strategy.

脑白质损伤与卒中后认知障碍（PSCI）的发生密切相关，小胶质细胞和星形胶质细胞的表型转变及交互作用是脑白质损伤与修复的重要机制，TREM2/DAP12通路可调控两种胶质细胞的应答。运动训练能改善PSCI，但机制未明。我们发现，运动训练能促进小胶质细胞向神经保护型转变，修复脑白质损伤，改善慢性脑缺血所致的认知障碍；预实验显示，运动训练还可调节星形胶质细胞向神经保护型转变，增加脑梗死大鼠脑内TREM2的表达。因此我们假设，运动训练可能通过激活TREM2/DAP12通路，促进小胶质细胞和星形胶质细胞向神经保护型转变，增强两者的交互作用，修复脑白质损伤，进而改善PSCI。本研究拟构建tMCAO运动训练模型，采用蛋白修饰组学、免疫电镜等方法，探讨运动训练是否通过调节神经胶质细胞应答改善PSCI，并明确TREM2/DAP12通路的作用，研究结果为深入了解PSCI的发病机制及优化其干预策略提供实验依据。

脑白质损伤与卒中后认知障碍（post-stroke cognitive impairment, PSCI）的发生密切相关，小胶质细胞和星形胶质细胞的表型转变及交互作用是脑白质损伤与修复的重要机制。然而，脑梗死后少突胶质细胞的分化明显受限。运动训练虽然能改善PSCI，但机制未明，近来研究认为调节神经胶质细胞应答可能是其中的重要机制，且TREM2/DAP12通路可通过调控胶质细胞改善脑白质损伤。本项目在前期研究的基础上，进一步探究运动训练是否通过激活TREM2/DAP12 信号通路，调节小胶质细胞和星形胶质细胞向神经保护型转变，并增强两者的交互作用，促进少突胶质细胞增殖分化，修复脑白质损伤，进而改善脑梗死大鼠的认知功能。.本研究通过构建大鼠大脑中动脉栓塞再灌注（transient middle cerebral artery occlusion，tMCAO）运动训练模型，运用 Morris 水迷宫、新物体识别实验等进行认知功能评估；进行在体及离体实验，通过 LFB 染色、免疫荧光、透射电镜、磁共振DTI成像等观察少突胶质细胞增殖分化及白质完整性，采用免疫荧光、ELISA、 RT-PCR、shRNA、Western blotting等全面观察小胶质细胞和星形胶质细胞的表型转变及交互作用，并探讨TREM2/DAP12 等信号通路在其中的作用。研究发现：运动训练通过促进脑梗死大鼠少突胶质前体细胞分化，修复髓鞘损伤，进而改善其认知功能障碍；运动训练可调控小胶质细胞向神经保护表型转变，并通过激活 Activin-A/Acvr 2B 信号通路促进少突胶质前体细胞分化；其潜在机制可能是运动训练上调 TREM2表达调控脑梗死大鼠小胶质细胞向神经保护表型转变，并通过TREM2/DAP12 信号通路介导小胶质细胞与星形胶质细胞的交互作用，修复髓鞘损伤。.本项目研究结果与预期结果基本相符，达到了本项目的研究目的，本研究发现了运动训练调控脑梗死后胶质细胞功能转变的潜在靶点，为优化脑梗死康复治疗策略进一步提供了科学依据和实验证据。