Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
African Swine Fever Regional Laboratory of China (Guangzhou), Guangzhou, China.
Front Immunol. 2022 Mar 25;13:827709. doi: 10.3389/fimmu.2022.827709. eCollection 2022.
African swine fever virus (ASFV) causes an acute, hemorrhagic, and highly contagious disease in domestic swine, leading to significant economic losses to the global porcine industry. Restriction factors of innate immunity play a critical in host antiviral action. However, function of swine restriction factors of innate immunity on ASFV has been seldomly investigated. In this study, we determined five homologues of swine interferon-induced transmembrane proteins (SwIFITM [named SwIFITM1a, -1b, -2, -3, and -5]), and we found that they all exhibit potent antiviral activity against ASFV. Expression profile analysis indicated that these SwIFITMs are constitutively expressed in most porcine tissues. Whether infected with ASFV or treated with swine interferon, the expression levels of SwIFITMs were induced . The subcellular localization of SwIFITMs was similar to that of their human homologues. SwIFITM1a and -1b localized to the plasma membrane, SwIFITM2 and -3 focused on the cytoplasm and the perinuclear region, while SwIFITM5 accumulated in the cell surface and cytoplasm. The overexpression of SwIFITM1a, -1b, -2, -3, or -5 could significantly inhibit ASFV replication in Vero cells, whereas knockdown of these genes could enhance ASFV replication in PAMs. We blocked the constitutive expression of endogenous IFITMs in Vero cells using a CRISPR-Cas9 system and then infected them with ASFV. The results indicated that the knockout of endogenous IFITMs could enhance ASFV replication. Finally, we expressed five SwIFITMs in knockout Vero cell lines and then challenged them with ASFV. The results showed that all of the SwIFITMs had a strong antiviral effect on ASFV. This research will further expand the understanding of the anti-ASFV activity of porcine IFITMs.
非洲猪瘟病毒（ASFV）会导致家猪发生急性、出血性和高度传染性疾病，给全球养猪业造成巨大的经济损失。先天免疫的限制因素在宿主抗病毒作用中起着关键作用。然而，先天免疫限制因子在 ASFV 中的功能很少被研究。在这项研究中，我们确定了 5 种猪干扰素诱导的跨膜蛋白（SwIFITM [命名为 SwIFITM1a、-1b、-2、-3 和-5]）的同源物，发现它们都对 ASFV 表现出强大的抗病毒活性。表达谱分析表明，这些 SwIFITMs 在大多数猪组织中均呈组成性表达。无论是感染 ASFV 还是用猪干扰素处理，SwIFITMs 的表达水平均被诱导上调。SwIFITMs 的亚细胞定位与它们的人类同源物相似。SwIFITM1a 和-1b 定位于质膜，SwIFITM2 和-3 集中于细胞质和核周区域，而 SwIFITM5 则在细胞表面和细胞质中积累。SwIFITM1a、-1b、-2、-3 或-5 的过表达可显著抑制 Vero 细胞中的 ASFV 复制，而这些基因的敲低则可增强 PAMs 中的 ASFV 复制。我们使用 CRISPR-Cas9 系统阻断 Vero 细胞中内源性 IFITMs 的组成性表达，然后用 ASFV 感染它们。结果表明，内源性 IFITMs 的敲除可增强 ASFV 复制。最后，我们在敲除 Vero 细胞系中表达了 5 种 SwIFITMs，然后用 ASFV 对其进行了挑战。结果表明，所有 SwIFITMs 对 ASFV 均具有很强的抗病毒作用。这项研究将进一步扩展我们对猪 IFITMs 抗 ASFV 活性的认识。
