泛素连接酶TRIM26调控TLRs介导炎症反应的分子机制研究

TLRs-mediated inflammatory response plays a key role in the innate immune resistance to bacterial and other pathogenic microorganisms. Excessive activation of TLRs will lead to injury of the body, so it is particularly important to study the regulation mechanism of TLRs inflammatory response signal pathway. We found that TNF-α, IL-6, IL-12 and other inflammatory factors induced by LPS in macrophages were significantly reduced after TRIM26 gene knockdown or knockout, and the phosphorylation of NF-kB and MAPK was also significantly reduced. Using the TRIM26 knockout gene mouse model, it was found that the response of TRIM26-/- mice to colitis and endotoxin was significantly weaker than that of WT mice. Immunoprecipation technology was used to preliminarily demonstrate that TRIM26 can bind to TAB1, TAK1 and other adaptor proteins. In this study, the molecular mechanism of TRIM26 regulating TLRs-mediated inflammatory response will be further studied using TRIM26-/-, TRIM26 Tg mice and molecular and cellular biological methods, so as to find the target of TRIM26 and its ubiquitination modification. This study will provide a new understanding of TLRs signal transduction mechanism, and provide a theoretical basis for finding gene transfection for the prevention and treatment of bacterial infection and endotoxin shock.

TLRs介导的炎症反应在固有免疫抵抗细菌等病原微生物感染过程中发挥着关键作用，TLRs的过度活化会导致机体出现损伤，因此研究TLRs炎症反应信号通路的调控机制显得尤为重要。我们发现TRIM26基因敲减或敲除后，LPS介导巨噬细胞产生的TNF-α、IL-6、IL-12等炎症因子降低，NF-kB、MAPK的磷酸化也降低；利用TRIM26敲基因小鼠模型，发现TRIM26-/-小鼠的结肠炎反应明显弱于野生型小鼠。利用免疫共沉淀技术初步探明TRIM26可以与TAB1、TAK1等接头蛋白发生结合。本课题将利用TRIM26敲基因小鼠及TRIM26转基因小鼠、分子细胞生物学手段深入研究TRIM26调控TLRs介导的炎症反应的分子机制，寻找TRIM26的作用靶点及对靶点的泛素化修饰形式。本研究将进一步完善TLRs介导炎症反应的泛素化调控机制，为研发天然免疫抵抗细菌感染的泛素化类药物供理论靶点

细菌感染是危害人类健康重要因素，细菌感染机体后，其产生的毒素和其他代谢产物可直接或者间接导致组织细胞损害或坏死，甚至引起机体的败血症或脓毒血症。研究机体自身抗细菌天然免疫信号转导的调控机制尤为重要，TAK1-TABs 复合体在TLRs介导的信号通路活化中发挥重要作用。本研究发现E3泛素连接酶TRIM26特异性结合蛋白TAB1，并催化TAB1第294、319和335位赖氨酸位点发生新型K11位泛素化修饰，进而正向调控TAK1的激活。TRIM26缺失抑制脂多糖LPS、TNF-α和IL-1β诱导的促炎细胞因子的产生，并改善LPS诱导的小鼠内毒素休克和DSS诱导的结肠炎的严重程度。这些发现为如何通过TRIM26介导的TAB1泛素化调控TAK1激活提供了一个新的视角，并揭示了TRIM26在炎症性先天免疫反应调控中的新功能。上述研究结果已发表在国际权威期刊Cell Death Differ，申请人为该论文的并列通讯作者。在本项目的资助下，申请人围绕“天然免疫信号转导的调控机制”进行开拓创新，探索性研究了精氨酸甲基转移酶PRMT9、去泛素化酶USP5、m6A甲基转移酶METTL14在抗感染固有免疫应答反应中的作用和机制，相关成果以并列通讯作者身份发表在国际权威期刊Nat Commun、Autophagy、Adv Sci杂志上。申请人作为项目负责人获得国家自然基金优秀青年科学基金项目1项，国家自然基金面上项目1项，山东省优秀青年科学基金项目1项。