趋化因子CCL2-CCR2轴调控环形泰勒虫感染的牛淋巴细胞迁移的作用机制

环形泰勒虫感染的牛淋巴细胞(TaLCs)具有肿瘤样细胞特性，可无限繁殖且迁移和侵袭能力增强。趋化因子是一类参与调控细胞迁移和细胞骨架重塑的小分子分泌蛋白。本课题组前期研究发现趋化因子CCL2及其受体CCR2在不同时期的TaLCs细胞中表达变化明显，推测CCL2-CCR2轴在调控TaLCs细胞迁移中发挥重要作用。因此，本项目从两个方面进行解析：(1)构建稳定过表达/沉默CCR2的TaLCs细胞株，通过CCL2重组蛋白刺激细胞，研究感染细胞迁移率和侵袭率的变化，明确CCL2-CCR2轴在感染细胞迁移中的生物学功能；(2)对TaLCs细胞进行处理，通过CCL2重组蛋白刺激，研究细胞骨架结构变化和细胞骨架相关蛋白磷酸化水平变化，明确CCL2-CCR2轴在感染细胞骨架重塑中的作用。预期结果将阐明CCL2-CCR2轴在TaLCs细胞迁移中的作用机制，为进一步理解环形泰勒虫在宿主体内扩散提供理论支撑。

Bovine lymphocytes infected by Theileria annulata (TaLCs) have the characteristics of tumor-like cells, which showed uncontrolled proliferation and increased motility and invasiveness. Chemokines are a family of small and secreted proteins involved in the regulation of cell migration and actin cytoskeleton rearrangement. In the preliminary study, we found that the expression of chemokine CCL2 and its receptor CCR2 were significantly changed during the early and late stages of TaLCs. It is predicted that CCL2-CCR2 axis could play important roles in the regulation of TaLCs cell migration. Therefore, in this project, we will focus on TaLCs and analyze it in two ways. Firstly, the CCR2 stable overexpression or interference TaLCs cell lines were constructed, and the recombinant protein CCL2 were added to stimulate cell lines to study the changes in the migration and invasion rates of infected cells. It will elucidate the biological functions of CCL2-CCR2 axis in infected cells migration. Secondly, TaLCs cells were treated with CCR2 antagonists or ROCK inhibitor, then the recombinant protein CCL2 were added to study the changes in cytoskeletal structure and phosphorylation of cytoskeleton-related proteins. It will elucidate the effects of CCL2-CCR2 axis on actin cytoskeleton reorganization of infected cells. These results will illuminate the mechanism of CCL2-CCR2 axis in TaLCs cell migration, and provide the theoretical foundation for further understanding the dissemination of Theileria annulata in the host.