Toll 样受体4（TLR4）在华支睾吸虫感染致肝纤维化中的作用及其分子机制

华支睾吸虫感染导致的肝纤维化或肝硬化严重威胁人类和动物的健康。研究表明TLR4 能促进肝星状细胞的活化，从而导致肝纤维化的发生。本课题组前期研究发现TLR4突变型小鼠能明显减轻华支睾吸虫感染所导致的肝纤维化，但其作用机制还未知。因此，本项目拟以TLR4识别华支睾吸虫有效虫体抗原并促进肝纤维化发生为切入点，利用相关基因缺陷型小鼠以及清除体内枯否细胞的小鼠建立华支睾吸虫感染模型，采用实时定量PCR、Western blot及流式细胞术等手段分析TLR4及其介导的信号通路在促肝纤维化中的作用机制。以此为基础，在细胞水平深入研究经华支睾吸虫有效抗原激活的TLR4及其介导的信号通路直接或间接促进TGF-β1/Smads信号通路活化肝星状细胞的作用机制。拟通过上述研究，揭示宿主细胞模式识别受体-TLR4促进华支睾吸虫致肝纤维化发生的分子机制，为防治华支睾吸虫致肝纤维化或肝硬化提供新的有效干预靶点。

Infection by Clonorchis sinensis can lead to liver fibrosis/cirrhosis, which poses great threatens to both humans and animals health. Accumulated lines of evidence indicate that Toll-like receptor 4 (TLR4) activated by pathogen-associated molecular patterns (PAMPs) plays a critical role in activation of hepatic stellate cells (HSCs), which causes hepatic fibrosis/cirrhosis ultimately. Our previous study showed that a significant reduction in hepatic fibrosis of TLR4 mutant mice was observed, compared with TLR4 wild mice with overt hepatic fibrosis in a mouse model of clonorchiasis. However，the mechanisms by which TLR4 signaling enhances HSC activation and liver fibrosis caused by C. sinensis remains unknown. The objective of the present project is to explore the underlying mechanisms of TLR4 signaling in promotion of liver fibrosis caused by C. sinensis. To achieve this goal, we established a mouse model of clonorchiasis; Based this mouse model, the roles of TLR4 signaling in the activation of HSC and promotion of liver fibrosis are to be analyzed by real-time PCR, Western-blot and Flow cytometry in TLR4 mutation and TLR4 wild mice, as well as in mice with Kupffer cell depletion. Furthermore, The roles of TLR4 activated by PAMPs from C. sinensis in TGF-β1- and Kupffer cell-mediated HSC activation are also to be explored in vivo. Our foundlings will dramatically advance our understanding of the interactions between Toll-like receptors of host cells and PAMPs sourced from C. sinensis, as well as provide novel therapeutic targets to treat this disease.