脾源性Tregs迁移至肝脏参与纤维化进展的机制研究

Treg cells play important roles in the progression of liver fibrosis by affecting the liver immune microenvironment, but the source of Tregs has been inconclusive. The spleen and liver are closely related in structure which can affect the liver microenvironment. The previous study found that the number of Tregs was significantly increased in spleen and liver of fibrosis mice. The splenectomy can reduce the number of Tregs and release the liver fibrosis, suggesting that liver Tregs may be partially derived from the spleen, but the mechanism is still unknown. This study intends to use liver fibrosis mouse model, spleen transplantation and Tregs adoptive transfer to detect the migration of spleen-derived Tregs to the fibrosis liver; Then use the chip technology to screen out the chemokines and receptors related to the migration of spleen-derived Tregs. The in vivo antibody blockade and in vitro cell co-culture will be used to verify the mechanism of spleen-derived Tregs migration. Then analyze the correlation between chemokines induced Tregs migration and disease characteristics. The results of this study will clarify the source of Tregs in the liver during fibrosis and may provide a new theoretical basis for the prevention and treatment of liver fibrosis.

Tregs可通过影响肝脏免疫微环境参与肝纤维化进展，但Tregs的来源尚不明确。脾脏与肝脏在结构及功能上联系密切，可影响肝脏免疫微环境。本课题前期研究发现，肝纤维化小鼠脾脏及肝脏中Tregs数量显著升高；脾脏切除可降低肝脏中Tregs的数量，纤维化程度亦得到缓解。故此推测，肝纤维化时，脾源性Tregs可在肝脏趋化因子募集作用下迁移至肝脏改变免疫微环境，进而促进肝纤维化进展。本课题拟利用CCl4诱导的肝纤维化小鼠模型，通过脾脏移植、脾源性Tregs过继回输技术明确脾源性Tregs迁移至肝脏以及对纤维化进展的影响；然后通过液相抗体芯片技术筛选与脾源性Tregs迁移相关的趋化因子及受体，利用体内抗体阻断及体外细胞共培养等技术进一步解析脾源性Tregs迁移至肝脏的分子机制；并在临床病例中分析脾源性Tregs及趋化因子与疾病特征的相关性。本课题有望为肝纤维化的防治提供新的实验与理论依据。

Tregs可通过影响肝脏免疫微环境参与肝纤维化进展，脾脏与肝脏在结构及功能上联系密切，可影响肝脏免疫微环境。本课题前期研究发现，肝纤维化小鼠脾脏及肝脏中Tregs数量显著升高；脾脏切除可降低肝脏中Tregs的数量，纤维化程度亦得到缓解。本项目旨在进一步分析肝纤维化时，脾源性Tregs在肝脏趋化因子募集作用下迁移至肝脏改变免疫微环境促进肝纤维化进展的具体作用机制。目前本项目已经顺利完成，目前正在投稿中，主要的实验结论：1 成功构建脾脏移植小鼠模型，对脾脏来源免疫细胞的迁移进行了检测，发现脾脏中Treg及DC细胞可以迁移至肝脏；2脾脏中的DC细胞表面CCR5及CCR7表达增高促进其向肝脏的迁移；3 脾脏DC呈现耐受表型，回输脾脏来源tolDC可以通过诱导肝脏T细胞向Treg细胞转化，发挥免疫抑制作用进而促进肝脏纤维化。