State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China.
J Virol. 2023 May 31;97(5):e0037523. doi: 10.1128/jvi.00375-23. Epub 2023 May 3.
Porcine deltacoronavirus (PDCoV) is an emerging swine enteropathogenic coronavirus that has the potential to infect humans. Histone deacetylase 6 (HDAC6) is a unique type IIb cytoplasmic deacetylase with both deacetylase activity and ubiquitin E3 ligase activity, which mediates a variety of cellular processes by deacetylating histone and nonhistone substrates. In this study, we found that ectopic expression of HDAC6 significantly inhibited PDCoV replication, while the reverse effects could be observed after treatment with an HDAC6-specific inhibitor (tubacin) or knockdown of HDAC6 expression by specific small interfering RNA. Furthermore, we demonstrated that HDAC6 interacted with viral nonstructural protein 8 (nsp8) in the context of PDCoV infection, resulting in its proteasomal degradation, which was dependent on the deacetylation activity of HDAC6. We further identified the key amino acid residues lysine 46 (K46) and K58 of nsp8 as acetylation and ubiquitination sites, respectively, which were required for HDAC6-mediated degradation. Through a PDCoV reverse genetics system, we confirmed that recombinant PDCoV with a mutation at either K46 or K58 exhibited resistance to the antiviral activity of HDAC6, thereby exhibiting higher replication compared with wild-type PDCoV. Collectively, these findings contribute to a better understanding of the function of HDAC6 in regulating PDCoV infection and provide new strategies for the development of anti-PDCoV drugs. As an emerging enteropathogenic coronavirus with zoonotic potential, porcine deltacoronavirus (PDCoV) has sparked tremendous attention. Histone deacetylase 6 (HDAC6) is a critical deacetylase with both deacetylase activity and ubiquitin E3 ligase activity and is extensively involved in many important physiological processes. However, little is known about the role of HDAC6 in the infection and pathogenesis of coronaviruses. Our present study demonstrates that HDAC6 targets PDCoV-encoded nonstructural protein 8 (nsp8) for proteasomal degradation through the deacetylation at the lysine 46 (K46) and the ubiquitination at K58, suppressing viral replication. Recombinant PDCoV with a mutation at K46 and/or K58 of nsp8 displayed resistance to the antiviral activity of HDAC6. Our work provides significant insights into the role of HDAC6 in regulating PDCoV infection, opening avenues for the development of novel anti-PDCoV drugs.
猪德尔塔冠状病毒（PDCoV）是一种新兴的猪肠道致病性冠状病毒，具有感染人类的潜力。组蛋白去乙酰化酶 6（HDAC6）是一种独特的 IIb 型细胞质去乙酰化酶，具有去乙酰化酶活性和泛素 E3 连接酶活性，通过去乙酰化组蛋白和非组蛋白底物来介导多种细胞过程。在本研究中，我们发现过表达 HDAC6 可显著抑制 PDCoV 复制，而在用 HDAC6 特异性抑制剂（tubacin）处理或通过特异性小干扰 RNA 敲低 HDAC6 表达后则可观察到相反的效果。此外，我们证明了 HDAC6 在 PDCoV 感染的情况下与病毒非结构蛋白 8（nsp8）相互作用，导致其被蛋白酶体降解，这依赖于 HDAC6 的去乙酰化活性。我们进一步鉴定出 nsp8 的关键氨基酸残基赖氨酸 46（K46）和 K58 分别为乙酰化和泛素化位点，这是 HDAC6 介导的降解所必需的。通过 PDCoV 反向遗传学系统，我们证实了在 K46 或 K58 处发生突变的重组 PDCoV 对 HDAC6 的抗病毒活性具有抗性，因此与野生型 PDCoV 相比，其复制能力更高。总之，这些发现有助于更好地理解 HDAC6 在调节 PDCoV 感染中的作用，并为开发抗 PDCoV 药物提供了新策略。 作为一种具有潜在人畜共患性的新兴肠道致病性冠状病毒，猪德尔塔冠状病毒（PDCoV）引起了极大的关注。组蛋白去乙酰化酶 6（HDAC6）是一种关键的去乙酰化酶，具有去乙酰化酶活性和泛素 E3 连接酶活性，广泛参与许多重要的生理过程。然而，关于 HDAC6 在冠状病毒感染和发病机制中的作用知之甚少。我们的研究表明，HDAC6 通过赖氨酸 46（K46）的去乙酰化和 K58 的泛素化靶向 PDCoV 编码的非结构蛋白 8（nsp8）进行蛋白酶体降解，从而抑制病毒复制。在 nsp8 的 K46 和/或 K58 处发生突变的重组 PDCoV 对 HDAC6 的抗病毒活性具有抗性。我们的工作为 HDAC6 在调节 PDCoV 感染中的作用提供了重要的见解，为开发新型抗 PDCoV 药物开辟了新的途径。
