Katwal Pratik, Aftab Shamiq, Nelson Eric, Hildreth Michael, Li Shitao, Wang Xiuqing
Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD 57007, USA.
Microorganisms. 2025 Jul 25;13(8):1737. doi: 10.3390/microorganisms13081737.
Interferon-induced transmembrane protein 3 (IFITM3) is a member of the family of interferon-stimulated genes (ISGs) that inhibits a diverse array of enveloped viruses which enter host cells by endocytosis. Porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped RNA virus causing significant economic losses to the swine industry. Very little is known regarding how IFITM3 restricts PRRSV. In this study, the role of IFITM3 in PRRSV infection was studied in vitro using MARC-145 cells. IFITM3 over-expression reduced PRRSV replication, while the siRNA-induced knockdown of endogenous IFITM3 increased PRRSV RNA copies and virus titers. The colocalization of the virus with IFITM3 was observed at both 3 and 24 h post infection (hpi). Quantitative analysis of confocal microscopic images showed that an average of 73% of IFITM3-expressing cells were stained positive for PRRSV at 3 hpi, while only an average of 27% of IFITM3-expressing cells were stained positive for PRRSV at 24 hpi. These findings suggest that IFITM3 may restrict PRRSV at the post-entry steps. Future studies are needed to better understand the mechanisms by which this restriction factor inhibits PRRSV.
干扰素诱导跨膜蛋白3（IFITM3）是干扰素刺激基因（ISG）家族的成员，可抑制多种通过内吞作用进入宿主细胞的包膜病毒。猪繁殖与呼吸综合征病毒（PRRSV）是一种包膜RNA病毒，给养猪业造成了巨大的经济损失。关于IFITM3如何限制PRRSV的了解非常少。在本研究中，使用MARC-145细胞在体外研究了IFITM3在PRRSV感染中的作用。IFITM3的过表达降低了PRRSV的复制，而siRNA诱导的内源性IFITM3敲低增加了PRRSV RNA拷贝数和病毒滴度。在感染后3小时（hpi）和24小时均观察到病毒与IFITM3的共定位。共聚焦显微镜图像的定量分析显示，在3 hpi时，平均73%表达IFITM3的细胞被PRRSV染色呈阳性，而在24 hpi时，平均只有27%表达IFITM3的细胞被PRRSV染色呈阳性。这些发现表明，IFITM3可能在病毒进入后的步骤中限制PRRSV。需要进一步的研究来更好地理解这种限制因子抑制PRRSV的机制。
