Jin Ke, Dai Yan, Ouyang Ke, Huang Huaying, Jiang Zhengyi, Yang Zhan, Zhou Tingting, Lin Hong, Wang Chunhui, Wang Chunyan, Sun Xuewei, Lu Dafeng, Liu Xiaoguang, Hu Nannan, Zhu Chuanlong, Zhu Jin, Li Jun
Department of Infectious Disease, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China.
Front Microbiol. 2023 Jul 14;14:1209870. doi: 10.3389/fmicb.2023.1209870. eCollection 2023.
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was caused by the (DBV), and it has become a global public health threat. Cytokine storm is considered to be an important pathogenesis of critical SFTS. Tripartite motif-containing 3 (TRIM3), as a member of the TRIM protein family, may contribute to the regulation of the immune and inflammatory responses after viral infection. However, whether TRIM3 plays a major role in the pathogenesis of SFTS has not yet been investigated.
TRIM3 mRNA levels were detected in PBMCs between 29 SFTS patients and 29 healthy controls by qRT-PCR. We established the pathogenic IFNAR SFTS mouse model successfully by inoculating subcutaneously with DBV and testing the expression levels of TRIM3 mRNA and protein by qRT-PCR and immunofluorescence in the livers, spleens, lungs, and kidneys. TRIM3 THP-1 cells and peritoneal macrophages extracted from TRIM3 mice were infected with DBV. The effect of TRIM3 on cytokines was detected by qRT-PCR and ELISA. Then we examined Toll-like receptor 3 (TLR3) and protein phosphorylation in the MAPK pathway after DBV infection using Western blot. Flow cytometry was used to verify TLR3 expression on peripheral blood monocytes in SFTS patients. We further explored the interaction between TRIM3 and TLR3 using CO-IP and Western blot.
Compared to healthy controls, TRIM3 mRNA expression in PBMCs is decreased in SFTS patients, especially in severe cases. TRIM3 mRNA and protein were synchronously reduced in the livers, spleens, lungs, and kidney tissues of the IFNAR SFTS mice model. In the DBV-infected cell model, TRIM3 overexpression can inhibit the DBV-induced release of IL-1β, IL-6, and TNF-α, the expression of TLR3, and protein phosphorylation in the MAPK pathway, which plays an anti-inflammatory role, while TRIM3 deficiency exacerbates the pro-inflammatory effects. We further found that TRIM3 can promote TLR3 degradation through K48-linked ubiquitination.
TRIM3 can inhibit the production of cytokines by regulating the degradation of TLR3 through K48-linked ubiquitination, which can be a therapeutic target for improving the prognosis of SFTS.
发热伴血小板减少综合征（SFTS）是一种由白蛉病毒属（DBV）引起的新发传染病，已成为全球公共卫生威胁。细胞因子风暴被认为是重症SFTS的重要发病机制。含三联基序蛋白3（TRIM3）作为TRIM蛋白家族成员，可能参与病毒感染后免疫和炎症反应的调节。然而，TRIM3在SFTS发病机制中是否起主要作用尚未见研究报道。
采用qRT-PCR检测29例SFTS患者和29例健康对照外周血单个核细胞（PBMCs）中TRIM3 mRNA水平。通过皮下接种DBV成功建立IFNAR SFTS小鼠致病模型，采用qRT-PCR和免疫荧光法检测肝脏、脾脏、肺脏和肾脏中TRIM3 mRNA和蛋白表达水平。用DBV感染从TRIM3小鼠提取的THP-1细胞和腹腔巨噬细胞。采用qRT-PCR和ELISA检测TRIM3对细胞因子的影响。然后用蛋白质印迹法检测DBV感染后Toll样受体3（TLR3）和丝裂原活化蛋白激酶（MAPK）途径中的蛋白磷酸化情况。采用流式细胞术验证SFTS患者外周血单核细胞上TLR3的表达。我们进一步通过免疫共沉淀和蛋白质印迹法探讨TRIM3与TLR3之间的相互作用。
与健康对照相比，SFTS患者PBMCs中TRIM3 mRNA表达降低，尤其是重症患者。在IFNAR SFTS小鼠模型的肝脏、脾脏、肺脏和肾脏组织中，TRIM3 mRNA和蛋白同步降低。在DBV感染的细胞模型中，TRIM3过表达可抑制DBV诱导的IL-1β、IL-6和TNF-α释放、TLR3表达及MAPK途径中的蛋白磷酸化，发挥抗炎作用，而TRIM3缺陷则加剧促炎效应。我们进一步发现TRIM3可通过K48连接的泛素化促进TLR3降解。
TRIM3可通过K48连接的泛素化调节TLR3降解来抑制细胞因子产生，这可能是改善SFTS预后的治疗靶点。
