IL-22调控kupffer细胞抑制肝纤维化的机制研究

Our previous study indicated that Th22/ IL-22 could alleviate liver fibrosis by inhibiting hepatic stellate cells (HSC) activity. Inherent liver macrophage, that is kupffer cells (KCs) has dual-direction regulation on the liver injury and repair, which implemented by the dynamic balance of M1/M2 KCs. Our preliminary results also demonstrated that the quantity of M1 KCs was more than M2 KCs in the liver fibrosis tissue and IL-22 could promote the differentiation of M2 KCs, and the activation of STAT3 during this process. We hypothesis that IL-22 may influence liver fibrosis via regulation of kupffer cells through STAT3 pathway. Therefore, in this study, we will extend our previous works and: clarify the effects and the of IL-22 on the regulation of KCs through STAT3 signal pathway; illustrate the mechanisms of macrophage migrating from peripheral blood to liver tissue and the influence of IL-22 on this process; elucidate the effects of KCs on the HSC, and the influence of IL-22 on the cross-talk of KCs and HSC, as well as the role of STAT3 signal pathway; expound the impact of IL-22 on the development and prognosis of liver fibrosis in mice model. Our study will give a new insight into the mechanism of IL-22 regulating KCs, and provide new idea for the prevention and treatment of liver fibrosis.

本项目前期研究表明Th22/IL-22通过抑制肝星状细胞(HSC)活性来影响肝纤维化进程。肝内巨噬细胞，即kupffer细胞(KCs)对肝脏的损伤修复有双向调节作用，这种作用通过M1/M2型KCs动态平衡实现。我们预实验结果提示肝纤维化组织中M1较M2型KCs多，IL-22可促进M0型KCs向M2型KCs分化，并上调STAT3表达水平，推测IL-22可能经STAT3通路调控KCs来抑制肝纤维化发生发展。因此，本项目将通过临床、细胞、动物三方面进行研究：阐明IL-22经STAT3通路调控KCs作用和机制；阐明巨噬细胞从外周血迁移至肝组织的机制和IL-22对迁移作用的影响；阐明KCs对HSC的作用以及IL-22经调控KCs影响HSC活性作用及其机制；在小鼠肝纤维化模型阐明IL-22经调控KCs活性抑制肝纤维化发生、发展及转归。本项目将从IL-22调控KCs这个新视点为肝纤维化防治提供新的思路。

本课题组前期研究证实白介素(IL)-22可抑制肝星状细胞(HSC)活性进而影响肝纤维化的转归。肝内kupffer细胞(KCs)通过M1/M2型的KCs动态平衡实现对肝脏的修复作用。我们预实验结果提示肝纤维化组织中M1型KCs较M2型多，且IL-22可促进M0型KCs向M2型KCs分化、上调STAT3因子表达水平，推测IL-22可能经STAT3通路诱导KCs分化来影响肝纤维化进程。因此，本项目将通过临床组织、细胞和动物模型研究：阐明STAT3通路在M1型和M2型KCs分化中的作用、IL-22经STAT3通路调控KCs机制；阐明IL-22经调控KCs影响HSC活性作用及其机制；建立小鼠肝纤维化模型，检测KCs的表型改变和STAT3的表达水平，在动物模型上阐明IL-22经调控KCs活性抑制肝纤维化进程。体内外研究表明，IL-22可通过上调STAT3/IL10R2通路抑制M1-KCs极化，并下调Erk1/2及Akt通路促进M2-KCs极化，改变M1/M2-KCs的极化平衡，减少促炎症因子的产生。此外，基于体内模型基础上构建体外共培养的实验证实，M2/M1-KCs比值升高，可显著抑制HSC的分泌活性。人体研究表明，IL-22, M1/M2-KCs主要分布于肝血窦及肝小叶中央静脉或汇管区域，其数量在纤维化早期逐渐增多，纤维化晚期则逐渐减少；在肝纤维化进展过程中，IL-22的表达与M1/M2-KCs存在显著的正相关。体内研究发现，IL-22在CCl4诱导肝纤维化小鼠模型中起着抑制肝纤维化的作用，其可能机制是经激活STAT3/IL-10R2信号通路，促进M2-KCs极化，进而抑制KCs促炎因子的分泌，其体内微环境改变，抑制肝纤维化进展。本项目将从IL-22调控KCs这个新视点为肝纤维化防治提供新的思路。项目整体研究已完成。