College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China.
International Joint Research Center for National Animal Immunology, Zhengzhou, Henan, China.
J Virol. 2024 Mar 19;98(3):e0168623. doi: 10.1128/jvi.01686-23. Epub 2024 Feb 20.
The porcine reproductive and respiratory syndrome virus (PRRSV) can lead to severe reproductive problems in sows, pneumonia in weaned piglets, and increased mortality, significantly negatively impacting the economy. Post-translational changes are essential for the host-dependent replication and long-term infection of PRRSV. Uncertainty surrounds the function of the ubiquitin network in PRRSV infection. Here, we screened 10 deubiquitinating enzyme inhibitors and found that the ubiquitin-specific proteinase 1 (USP1) inhibitor ML323 significantly inhibited PRRSV replication . Importantly, we found that USP1 interacts with nonstructural protein 1β (Nsp1β) and deubiquitinates its K48 to increase protein stability, thereby improving PRRSV replication and viral titer. Among them, lysine at position 45 is essential for Nsp1β protein stability. In addition, deficiency of USP1 significantly reduced viral replication. Moreover, ML323 loses antagonism to PRRSV rSD16-K45R. This study reveals the mechanism by which PRRSV recruits the host factor USP1 to promote viral replication, providing a new target for PRRSV defense.IMPORTANCEDeubiquitinating enzymes are critical factors in regulating host innate immunity. The porcine reproductive and respiratory syndrome virus (PRRSV) nonstructural protein 1β (Nsp1β) is essential for producing viral subgenomic mRNA and controlling the host immune system. The host inhibits PRRSV proliferation by ubiquitinating Nsp1β, and conversely, PRRSV recruits the host protein ubiquitin-specific proteinase 1 (USP1) to remove this restriction. Our results demonstrate the binding of USP1 to Nsp1β, revealing a balance of antagonism between PRRSV and the host. Our research identifies a brand-new PRRSV escape mechanism from the immune response.
猪繁殖与呼吸综合征病毒（PRRSV）可导致母猪严重繁殖问题、断奶仔猪肺炎和死亡率增加，对经济造成重大负面影响。翻译后修饰对于 PRRSV 的宿主依赖性复制和长期感染至关重要。泛素网络在 PRRSV 感染中的功能尚不清楚。在这里，我们筛选了 10 种去泛素化酶抑制剂，发现泛素特异性蛋白酶 1（USP1）抑制剂 ML323 可显著抑制 PRRSV 复制。重要的是，我们发现 USP1 与非结构蛋白 1β（Nsp1β）相互作用，并去泛素化其 K48 以增加蛋白稳定性，从而改善 PRRSV 复制和病毒滴度。其中，位置 45 的赖氨酸对于 Nsp1β蛋白稳定性至关重要。此外，USP1 缺乏显著降低病毒复制。此外，ML323 对 PRRSV rSD16-K45R 失去拮抗作用。本研究揭示了 PRRSV 招募宿主因子 USP1 促进病毒复制的机制，为 PRRSV 防御提供了新的靶点。
去泛素化酶是调节宿主固有免疫的关键因素。猪繁殖与呼吸综合征病毒（PRRSV）非结构蛋白 1β（Nsp1β）对于产生病毒亚基因组 mRNA 和控制宿主免疫系统至关重要。宿主通过泛素化 Nsp1β 抑制 PRRSV 增殖，反之，PRRSV 招募宿主蛋白泛素特异性蛋白酶 1（USP1）去除这种限制。我们的结果表明 USP1 与 Nsp1β 的结合，揭示了 PRRSV 与宿主之间拮抗作用的平衡。我们的研究确定了 PRRSV 逃避免疫反应的全新机制。
