病原诱导鱼类DC表面共刺激分子表达的表观遗传调控机制

Dendritic cells (DCs) are among the most important professional antigen-presenting cells (APCs) that participate in various biological activities in mammals. However, the activation mechanism of DC, especially the regulation mechanism of expression of co-stimulatory molecules on DC remains poorly defined. This study focuses on the regulation of co-stimulatory molecules expression on the surface of dendritic cells in teleost fish, and explores the correlative mechanism between innate immune signaling pathway and epigenetic regulation pathway under pathogen induction. By establishing a fish DC isolation culture system, using real-time quantitative PCR and flow cytometry, we detect the difference in expression distribution of representative costimulatory molecules on the DC surface. Furthermore, CpG-ODN and recombinant HMGB1 protein treatment experiments, combined with immunosuppressive pathway inhibitor experiments, are used to elucidate the status and mechanism of infection and injury signaling pathways in the expression of co-stimulatory signals induced by pathogen infection. With ChIP-PCR technology, the intrinsic relationship between DNA methylation modification and histone methylation/acetylation modification during the formation of representative costimulatory signals are investigated to elucidate its epigenetic mechanism and reveal the personality and common characteristics of the expression regulation of costimulatory molecules. This study will deepen people's understanding of the regulation mechanism of co-stimulatory signal molecule expression and enrich the content of fish immunology.

本项目拟在鱼类中开展树突状细胞表面共刺激分子表达调控的研究，探索病原诱导下先天免疫信号通路与表观遗传调节途径间的偶联机制。通过建立鱼类DC分离培养体系，利用实时荧光定量PCR技术、流式细胞术检测代表性共刺激分子在DC表面的表达分布差异。利用CpG-ODN和重组HMGB1蛋白处理实验，结合免疫信号通路抑制剂实验，阐明感染和损伤信号途径在机体应对病原菌感染启动共刺激信号表达中的地位和机制。利用CHIP-qPCR技术，研究代表性共刺激信号形成过程中DNA甲基化修饰和组蛋白甲基化/乙酰化修饰间的内在联系，阐明其表观遗传学机制，揭示共刺激分子表达调控的个性与共性特征。相关研究成果将加深人们对共刺激信号分子表达调节机制的认识，丰富鱼类免疫学内容。同时也为鱼类疫苗及免疫佐剂的开发应用提供新的思路和策略。

本项目在斑马鱼和大黄鱼中开展了树突状细胞表面共刺激分子CD80/86、CD40和CD83表达调控的研究，探索了病原诱导下TLR9/NF-kB和mapk/p38先天免疫通路与表观遗传调节途径间的偶联机制。建立了鱼类DC分离培养体系，并利用实时荧光定量PCR技术、流式细胞术检测共刺激分子CD80/86、CD40和CD83在DC表面的表达分布差异。利用CpG-ODN处理实验，结合免疫信号通路抑制剂实验，阐明感染信号途径TLR9/NF-kB和mapk/p38在机体应对病原菌感染启动共刺激信号表达中的地位和机制。利用CHIP-qPCR等技术，揭示了稳态下DC特异性转录因子ZBTB46通过与启动子结合，招募Mdb3/NuRD和Hdac3/NCoR1复合物，建立抑制性组蛋白表观遗传修饰模式的机制，并发现了在感染条件下，Cullin1/Fbxw11复合体介导了ZBTB46的降解及共刺激分子启动子区的表观遗传重编程机制。相关研究成果将加深了人们对共刺激信号分子表达调节机制的认识，丰富鱼类免疫学内容。同时也为鱼类疫苗及免疫佐剂的开发应用、建立正确和适度地调控特异性免疫应答新技术，提供新的思路和策略。