Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural Universitygrid.22935.3f, Beijing, China.
College of Veterinary Medicine, China Agricultural Universitygrid.22935.3f, Beijing, China.
J Virol. 2022 Jul 27;96(14):e0075922. doi: 10.1128/jvi.00759-22. Epub 2022 Jul 6.
Avian reovirus (ARV) causes viral arthritis, chronic respiratory diseases, retarded growth, and malabsorption syndrome. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression posttranscriptionally by silencing or degrading their targets, thus playing important roles in the host response to pathogenic infection. However, the role of miRNAs in host response to ARV infection is still not clear. In this study, we show that ARV infection markedly increased gga-miR-30c-5p expression in DF-1 cells and that transfection of cells with gga-miR-30c-5p inhibited ARV replication while knockdown of endogenous gga-miR-30c-5p enhanced viral growth in cells. Importantly, we identified the autophagy related 5 (ATG5), an important proautophagic protein, as a bona fide target of gga-miR-30c-5p. Transfection of DF-1 cells with gga-miR-30c-5p markedly reduced ATG5 expression accompanied with reduced conversion of ARV-induced-microtubule-associated protein 1 light chain 3 II (LC3-II) from LC3-I, an indicator of autophagy in host cell, while knockdown of endogenous gga-miR-30c-5p enhanced ATG5 expression as well as ARV-induced conversion of LC3-II, facilitating viral growth in cells. Furthermore, knockdown of ATG5 by RNA interference (RNAi) or treatment of cells with autophagy inhibitors (3-MA and wortmannin) markedly reduced ARV-induced LC3-II and syncytium formation, suppressing viral growth in cells, while overexpression of ATG5 increased ARV-induced LC3-II and syncytium formation, promoting viral growth in cells. Thus, gga-miR-30c-5p suppressed viral replication by inhibition of ARV-induced autophagy via targeting ATG5. These findings unraveled the mechanism of how host cells combat against ARV infection by self-encoded small RNA and furthered our understanding of the role of microRNAs in host response to pathogenic infection. Avian reovirus (ARV) is an important poultry pathogen causing viral arthritis, chronic respiratory diseases, and retarded growth, leading to considerable economic losses to the poultry industry across the globe. Elucidation of the pathogenesis of ARV infection is crucial to guiding the development of novel vaccines or drugs for the effective control of these diseases. Here, we investigated the role of miRNAs in host response to ARV infection. We found that infection of host cells by ARV remarkably upregulated gga-miR-30c-5p expression. Importantly, gga-miR-30c-5p suppressed ARV replication by inhibition of ARV-induced autophagy via targeting autophagy related 5 (ATG5) accompanied by suppression of virus-induced syncytium formation, thus serving as an important antivirus factor in host response against ARV infection. These findings will further our understanding of how host cells combat against ARV infection by self-encoded small RNAs and may be used as a potential target for intervening ARV infection.
禽呼肠孤病毒（ARV）可引起病毒性关节炎、慢性呼吸道疾病、生长迟缓以及吸收不良综合征。微小 RNA（miRNA）是一类小的非编码 RNA，可通过沉默或降解其靶标来实现基因表达的转录后调控，因此在宿主对病原感染的反应中发挥着重要作用。然而，miRNA 在宿主对 ARV 感染反应中的作用尚不清楚。在本研究中，我们发现 ARV 感染可显著增加 DF-1 细胞中gga-miR-30c-5p 的表达，而用gga-miR-30c-5p 转染细胞可抑制 ARV 复制，而内源性 gga-miR-30c-5p 的敲低则增强了病毒在细胞中的生长。重要的是，我们鉴定出自噬相关蛋白 5（ATG5）是 gga-miR-30c-5p 的一个真正的靶标。用 gga-miR-30c-5p 转染 DF-1 细胞可显著降低 ATG5 的表达，同时 ARV 诱导的微管相关蛋白 1 轻链 3 II（LC3-II）从 LC3-I 的转化减少，LC3-I 是宿主细胞中自噬的一个指标，而内源性 gga-miR-30c-5p 的敲低则增强了 ATG5 的表达和 ARV 诱导的 LC3-II 的转化，促进了病毒在细胞中的生长。此外，用 RNA 干扰（RNAi）敲低 ATG5 或用自噬抑制剂（3-MA 和渥曼青霉素）处理细胞，可显著降低 ARV 诱导的 LC3-II 和合胞体的形成，从而抑制病毒在细胞中的生长，而 ATG5 的过表达则增加了 ARV 诱导的 LC3-II 和合胞体的形成，促进了病毒在细胞中的生长。因此，gga-miR-30c-5p 通过靶向 ATG5 抑制 ARV 诱导的自噬来抑制病毒复制。这些发现揭示了宿主细胞通过自身编码的小 RNA 来对抗 ARV 感染的机制，并进一步加深了我们对 miRNA 在宿主对病原感染反应中的作用的理解。
禽呼肠孤病毒（ARV）是一种重要的家禽病原体，可引起病毒性关节炎、慢性呼吸道疾病和生长迟缓，给全球家禽业造成了巨大的经济损失。阐明 ARV 感染的发病机制对于指导新型疫苗或药物的开发以有效控制这些疾病至关重要。在这里，我们研究了 miRNA 在宿主对 ARV 感染反应中的作用。我们发现，宿主细胞感染 ARV 可显著上调 gga-miR-30c-5p 的表达。重要的是，gga-miR-30c-5p 通过靶向自噬相关蛋白 5（ATG5）抑制 ARV 诱导的自噬，从而抑制 ARV 复制，并抑制病毒诱导的合胞体形成，因此在宿主对 ARV 感染的反应中作为一种重要的抗病毒因子发挥作用。这些发现将进一步加深我们对宿主细胞通过自身编码的小 RNA 来对抗 ARV 感染的理解，并可能成为干预 ARV 感染的潜在靶点。
