p38 MAPK - PPARγ/NF-κB信号通路在脑缺血预处理上调GLT-1表达诱导脑缺血耐受中的机制

研究发现脑缺血预处理(CIP)通过上调GLT-1表达诱导脑缺血耐受，但其信号机制尚不清楚。深入研究其机制，可为阐明脑缺血耐受诱导机制提供实验依据，为脑缺血性疾病的治疗提供新思路，具有重要意义。我们在2011年科学部主任基金资助下，初步探讨了在体情况下p38 MAPK-PPARγ/NF-κB信号通路在CIP上调GLT-1表达诱导脑缺血耐受过程中的作用。发现CIP上调p38 MAPK、PPARγ及NF-κB的表达，分别预先应用其特异性抑制剂SB203580、GW9662、BAY11-7082均可抑制CIP的脑保护作用。据此，本课题应用免疫组化、Western blot、免疫共沉淀、EMSA、PCR、siRNA、微透析、高效液相色谱等技术，进一步在整体水平和细胞水平、从表达和功能两方面深入研究CIP通过p38 MAPK-PPARγ/NF-κB信号通路引起GLT-1表达上调而发挥脑保护作用的机制。

It has been found that the up-regulation of glial glutamate transporter-1 (GLT-1) participates in the induction of brain ischemic tolerance induced by cerebral ischemic preconditioning (CIP). However, the underlying mechanisms are not clear until now. It is very important to clarify the mechanism, because it will provide experiment fundament for clarifying the mechanisms of brain ischemic tolerance and new clue for treatment of brain ischemia. Under the financial assistance of The Director Foundation of Science Ministry, the role of p38 MAPK - PPARγ/NF-κB signaling path way in the induction of brain ischemic tolerance via the up-regulation of GLT-1 induced by CIP in vivo was studied by us. Our recent findings showed that CIP increased the expression of p38 MAPK, PPARγ as well as NF-κB in hippocampus. Meanwhile, SB203580 (an inhibitor of p38 MAPK), GW9662 (an inhibitor of PPARγ) or BAY 11-7082 (an inhibitor of NF-κB) attenuated the protective effect of CIP. Thus, we presume that p38 MAPK may play a role in the GLT-1 up-regulation via PPARγ/NF-κB signaling pathway during the induction of brain ischemic tolerance induced by CIP. The present project was designed to prove the hypothesis in vivo and in vitro experiments, by determination of changes in the expression and function of GLT-1 and the signaling pathway using immunohistochemistry, western blot, coimmunoprecipitation, electrophoretic mobility shift assay (EMSA), real time-PCR, siRNA, microdialysis and high-performance liquid chromatography.