TRIP在抗病毒天然免疫中的作用及机制研究

Type I interferons, which play an essential role to eliminate viral infection, are mainly produced by the innate immune system through the recognition between pattern recognition receptors and viral RNA during viral infection. We have demonstrated that TRIP （TRAF-interacting protein）expression was substantially induced with stimulation of LPS (TLR4 ligand) and poly(I:C) (TLR3 ligand) in thioglycolate-elicited mouse primary peritoneal macrophages. siRNA knockdown of endogenous TRIP expression resulted in augmented expression of IFN-β in TLR3/4-activated and SeV-infected primary peritoneal macrophages, while overexpression of TRIP had opposite effects. These data suggest that TRIP may be involved in the regulation of TLR signaling and production of IFN-β. We propose that TRIP negatively regulates type I interferon production as a feedback molecule. However, the underlying molecular mechanisms and the functions of TRIP in antiviral infection are not clear. In this following proposal, we plan to use various of cells including MEFs from TRIP-deficient mice, macrophages and HEK293 cells combining with varieties of molecular techniques such as RT-PCR, Dual-Luciferase Reporter Assay, co-immunoprecipitation, in vitro and in vivo ubiquitination et al. to explore the functions of TRIP in the producton of IFN-β and antiviral immune responses. We will also identify the molecules that are targeted by TRIP in TLR and RLR signaling to reveal the possible molecular mechanims. Our study is the first to explore the functions of TRIP in the reguation of innate immune resonses and may provide a new approach for the prevention of viral diseases using gene transfection.

I型干扰素在抗病毒感染中发挥重要作用，其产生主要依赖于天然免疫系统的模式受体例如TLR3和RIG-I对病毒RNA的识别。我们前期工作发现，LPS和poly(I:C)可诱导巨噬细胞中TRIP的表达；siRNA干扰TRIP表达后，LPS、poly(I:C)和SeV诱导的IFN-β表达明显增强，提示TRIP可能参与病毒感染介导的IFN-β表达，但其分子调控机制及在抗病毒感染中的作用还不清楚。本研究拟利用细胞模型(TRIP缺陷鼠的MEF、巨噬细胞、HEK293等)和分子技术手段(报告基因分析、免疫共沉淀、体外泛素化等)探讨TRIP在IFN-β表达及其在抗病毒感染中的作用，并通过研究TRIP与MAVS、TBK1、IRF3等信号分子的相互作用，揭示其可能的分子机制。本研究首次提出TRIP的表达可能作为反馈信号调节I型干扰素的产生，可为寻找基因转染防治病毒性疾病免疫调节疗法提供新途径。

I型干扰素在抗病毒感染中发挥重要作用，其产生主要依赖于天然免疫系统的模式受体例如TLR3和RIG-I/MDA5对病毒RNA的识别，但其调控机制并不清楚。本研究发现了一个调控I型干扰素产生和抗病毒免疫反应的重要负向调控因子，并阐明了其作用机制。siRNA敲减泛素连接酶TRIP（TRAF-interacting protein）表达促进了TLR3/4及RLR信号通路所诱导的转录因子IRF3活化、I型干扰素（IFN-β）产生以及抗病毒免疫反应，而TRIP过表达则抑制了TLR3/4及RLR信号通路所诱导的IRF3活化、IFN-β产生和抗病毒免疫反应。进一步发现TRIP可与抗病毒信号转导通路中的关键激酶分子TBK1相互结合，进而促进TBK1进行K48连接的泛素化修饰，从而促进TBK1的降解，抑制抗病毒免疫反应。本课题首次发现了介导TBK1进行K48泛素化修饰和降解的泛素连接酶TRIP，并且揭示了一条新的病毒逃逸机制，为I型干扰素表达调控机制提出新的认识，为抗病毒感染药物研发提供了新的靶点。