Institute of Virology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany.
Marinomed Biotech AG, A-2100 Korneuburg, Austria.
Viruses. 2022 Jun 27;14(7):1404. doi: 10.3390/v14071404.
The ubiquitin proteasome system (UPS), particularly its deubiquitinating enzymes (DUBs), play a key role in the replication cycle of coronaviruses. The SARS-CoV-2 papain-like protease (Plpro) is known to process the viral polyproteins to form the replicase transcriptase complex and to counteract the host viral response. Recently, it was shown that this viral protease can also act as a deubiquitinating enzyme. In this study, we demonstrate that certain DUB-Inhibitors (DIs) interfere with SARS-CoV-2 replication. The DIs PR-619 and HBX41108 restrict SARS-CoV-2 in both Vero B4 and human Calu-3 lung cells where cells were infected with a Multiplicity of Infection (MOI) of 0.02. An in vitro protease assay using recombinant Plpro and Amido-4-methylcoumarin (AMC)-conjugated substrate revealed that PR-619 and HBX41108 are able to block the protease at concentrations where the interventions restricted virus replication. In contrast, DIs that do not inhibit Plpro had no influence on virus replication, which indicated that the protease might be at least one major target. Future vertical studies that would gain more insights into the mechanisms of how DUBs effect the replication of SARS-CoV-2 will further validate them as a potential therapeutic target.
泛素蛋白酶体系统（UPS），特别是其去泛素化酶（DUBs），在冠状病毒的复制周期中发挥着关键作用。已知 SARS-CoV-2 的木瓜蛋白酶样蛋白酶（Plpro）可加工病毒多聚蛋白以形成复制酶转录酶复合物，并抵抗宿主的病毒反应。最近，研究表明这种病毒蛋白酶也可以作为去泛素化酶。在这项研究中，我们证明了某些 DUB 抑制剂（DIs）可干扰 SARS-CoV-2 的复制。DIs PR-619 和 HBX41108 在感染 MOI 为 0.02 的 Vero B4 和人 Calu-3 肺细胞中均能限制 SARS-CoV-2 的复制。使用重组 Plpro 和 Amido-4-methylcoumarin（AMC）缀合的底物进行的体外蛋白酶测定表明，PR-619 和 HBX41108 能够在抑制病毒复制的浓度下阻断蛋白酶。相比之下，不抑制 Plpro 的 DIs 对病毒复制没有影响，这表明蛋白酶可能是至少一个主要靶标。未来的纵向研究将更深入地了解 DUBs 如何影响 SARS-CoV-2 复制的机制，从而进一步验证它们作为潜在治疗靶标的可能性。
