TOPK介导脑缺血中性粒细胞增殖和表型转化的机制研究

中性粒细胞增殖、迁移、表型转化参与脑缺血发生、发展及修复过程。我们前期发现：急性缺血性卒中患者血中性粒细胞TOPK表达显著升高，与中性粒细胞N2表型标记蛋白CD206成正相关且小鼠脑缺血组织中TOPK也与中性粒细胞标记蛋白有关；TOPK下游靶蛋白HDAC2表达显著减少，CHIP-sequence联合生物信息学分析显示与HDAC2结合的基因参与中性粒细胞转录调控、细胞裂解等；TOPK与转录因子Nrf2和PPARγ在小鼠模型都存在共定位；以上研究提示TOPK在脑缺血后可能靶向HDAC2、Nrf2和PPARγ参与中性粒细胞增殖和表型转化。因此，本课题拟验证假说：TOPK通过①调节Nrf2/cdc2/cyclinB通路参与中性粒细胞增殖；②靶向HDAC2，促使NF-κB核转移；③激活P38MAPK，提高PPARγ转录活性促进中性粒细胞向N2表型转化，从而抑制脑缺血炎性反应并促进神经功能恢复。

Neutrophil proliferation, migration and phenotypic transformation are involved in the occurrence, development and repair of cerebral ischemia. We found that the level of TOPK mRNA was significantly increased in peripheral neutrophils of patients with acute ischemic stroke, and positively correlated with CD206, a phenotypic marker of N2; moreover, TOPK was co-localized with neutrophil marker Ly6G in ischemic mouse brain. As a downstream target of TOPK, HDAC2 was significantly reduced in peripheral neutrophils and CHIP-sequence combined with bioinformatics analysis showed that genes targeted by HDAC2 involved in negative regulation of transcription, cytolysis and so on. Besides, TOPK was co-localized with transcription factors Nrf2 and PPARγ in mouse models. The above data all suggest that TOPK may participate in neutrophil proliferation and phenotypic transformation by targeting HDAC2, Nrf2 and PPARγ following cerebral ischemia. The project intends to verify the hypothesis that①TOPK participates in neutrophil proliferation by regulating Nrf2/cdc2/cyclin B pathway, ②targeting HDAC2 to increase nuclear translocation of NF-ΚB, ③activating P38MAPK, enhancing PPARγ transcriptional activity to promote the transformation of neutrophils to N2 phenotype, thereby inhibiting inflammatory response of cerebral ischemia and promoting neurological function recovery.