以多靶点调控为特征的转录因子Blimp-1抑制炎性因子表达的机制研究

“Cytokine storm” is an important reason of death of sepsis. Clinical research found that single-cytokine-targeting therapies have limitations, therefore, looking for novel molecular “switch” for regulation of a variety of pro-inflammatory factor become the breakthrough and hope for sepsis in the future. Based on the previous NSFC program, we found a transcription factor Blimp-1, which is a downstream repressor of TLR signaling pathway. We also identified one or more binding sites of Blimp-1 in the promoter region of many pro-inflammatory cytokines and chemokines through bioinformatics analysis. Thus, we proposed the hypothesis that Blimp-1 could suppress expression and secretion of a variety of pro-inflammatory cytokines and chemokines through the way of “one-to-many”, it might be the multi-targeting molecular “switch” for regulating on many pro-inflammatory cytokines and chemokines. We will confirm the roles of Blimp-1 on immune injury of sepsis through cell and mouse models in vivo and in vitro. Furthermore, we will illustrate the regulatory mechanisms of Blimp-1 on cytokine/chemokine expression through technology of ChIP, co-IP, immunofluorescence, RNAi and dual-luciferase reporter gene assay, combined with genomics high-throughput sequencing analysis. Our program will expanded the research on Blimp-1 from adaptive immune system to innate immune system and provide new target for alleviate the immune injury caused by “cytokine storm” and treatment of sepsis.

“细胞因子风暴”是脓毒症患者死亡的重要因素，但是临床研究发现：针对单一细胞因子的靶向治疗具有局限性。因此，寻找能够调控多种炎性因子的“开关”分子成为今后临床的突破点和希望。申请人在前一项国自然项目研究中发现：Blimp-1是TLR下游的转录抑制因子，生物信息学分析多种炎性因子启动子区域，均发现一至多个Blimp-1结合位点，提出：Blimp-1可能通过“单对多”的方式，抑制多种炎性因子转录，可能是多靶点调控炎性因子表达的“开关”分子。申请人拟采用细胞模型和脓毒症小鼠模型，体内、体外证实Blimp-1对脓毒症免疫损伤的影响；在ChIP-seq的基础上，采用ChIP-PCR、co-IP、免疫荧光、RNAi和双荧光报告等实验，阐明Blimp-1多靶点调控炎性因子表达的分子机制，将Blimp-1的研究由适应性免疫系统拓展到天然免疫，为减轻“细胞因子风暴”造成的免疫损伤、治疗脓毒症提供新靶点。

细胞因子风暴是脓毒症患者死亡的重要因素，但既往针对单一细胞因子的靶向治疗具有局限性。本研究发现转录因子Blimp-1能抑制多种炎性细胞因子分泌。我们采用CLP脓毒症小鼠模型，证实感染后Blimp-1在单核细胞、中性粒细胞等髓系细胞中的表达显著上调，并在急性期达到高峰。我们在单核巨噬细胞的体外研究中，采用shRNA技术结合转录组测序、代谢组学高通量分析，证实Blimp-1通过调控嘌呤合成途径和谷氨酰胺分解途径促进M2型巨噬细胞极化，从而抑制IL-12，TNF-α，IL-1β等多种炎性细胞因子分泌。此外，Blimp-1还能通过上调PD-1和TIGIT的转录表达，抑制T淋巴细胞分泌IFN-γ和IL-2，引起T细胞耗竭。综上，本研究初步揭示了Blimp-1发挥多靶点抑炎作用的免疫代谢调控机制，为减轻细胞因子风暴介导的脓毒症免疫损伤提供了新的分子靶点，也将为其他过度炎症反应相关疾病如自身免疫病提供新的研究思路。