Ren Haojie, Shi Lan-Fang, Wang Yanjin, Pan Xiao-Ya, Li Su, Ma Yu-He, Fan Jun-Hao, Chen Xing, Yang Zhong-Yuan, Fan Shuai, Zhang Yuhang, Han Shichong, He Wen-Rui, Wan Bo, Qiu Hua-Ji, Zhang Gai-Ping
International Joint Research Centre of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China.
State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-Reference Laboratory, National High-Containment Facilities for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, Heilongjiang, China.
J Virol. 2025 May 20;99(5):e0222524. doi: 10.1128/jvi.02225-24. Epub 2025 Mar 31.
African swine fever virus (ASFV) is a large double-stranded DNA virus, which is the causative agent of African swine fever (ASF), a devastating disease of suids epidemic in many countries. The virus has developed multiple strategies to evade surveillance from the host immune system. Inflammatory responses, especially the NF-B signaling pathway, play central roles in ASFV pathogenesis and immunoevasion. In this study, we identified the ASFV S273R protein (pS273R) as an antagonist of the canonical NF-B signaling pathway independently of its protease activity. The ectopically expressed pS273R markedly inhibited the tumor necrosis factor-alpha or interleukin-1 beta-triggered NF-B signaling pathway in HEK293T and PK-15 cells. Silencing pS273R by RNA interference led to elevated expression levels of proinflammatory cytokines in the ASFV-infected primary porcine alveolar macrophages. Mechanistically, pS273R functioned independently of its protease activity. pS273R was associated with the NF-B complex and interrupted the translocation of IB into the proteasome, resulting in the increased stability of IB and subsequently impaired nuclear translocation of p65. Furthermore, the core domain (amino acids 83-273) of pS273R was essential for the pS273R-mediated inhibition of the NF-B signaling pathway. These findings demonstrate the immunosuppressive role of pS273R and provide novel insights into ASFV biological characteristics.IMPORTANCEAfrican swine fever (ASF) is a hemorrhagic disease of suids caused by African swine fever virus (ASFV), with morbidity and mortality rates of up to 100%. The disease has led to significant economic losses to the global swine industry. In this study, we identify the ASFV S273R protein (pS273R) as an antagonist of the canonical NF-B signaling pathway. Our findings demonstrate the immunosuppressive role of pS273R, which will contribute to a better understanding of the pathogenesis of ASFV and may contribute to the development of antiviral therapies against ASF.
非洲猪瘟病毒（ASFV）是一种大型双链DNA病毒，它是非洲猪瘟（ASF）的病原体，ASF是一种在许多国家流行的猪的毁灭性疾病。该病毒已发展出多种策略来逃避宿主免疫系统的监测。炎症反应，尤其是NF-κB信号通路，在ASFV发病机制和免疫逃避中起核心作用。在本研究中，我们鉴定出ASFV S273R蛋白（pS273R）是经典NF-κB信号通路的拮抗剂，与其蛋白酶活性无关。异位表达的pS273R显著抑制了肿瘤坏死因子-α或白细胞介素-1β触发的HEK293T和PK-15细胞中的NF-κB信号通路。通过RNA干扰沉默pS273R导致ASFV感染的原代猪肺泡巨噬细胞中促炎细胞因子表达水平升高。从机制上讲，pS273R的功能与其蛋白酶活性无关。pS273R与NF-κB复合物相关，并阻断IκB向蛋白酶体的转运，导致IκB稳定性增加，随后p65的核转运受损。此外，pS273R的核心结构域（氨基酸83-273）对于pS273R介导的NF-κB信号通路抑制至关重要。这些发现证明了pS273R的免疫抑制作用，并为ASFV生物学特性提供了新的见解。重要性非洲猪瘟（ASF）是由非洲猪瘟病毒（ASFV）引起的猪的出血性疾病，发病率和死亡率高达100%。该疾病给全球养猪业带来了巨大的经济损失。在本研究中，我们鉴定出ASFV S273R蛋白（pS273R）是经典NF-κB信号通路的拮抗剂。我们的发现证明了pS273R的免疫抑制作用，这将有助于更好地理解ASFV的发病机制，并可能有助于开发针对ASF的抗病毒疗法。
