Autophagy enhances the replication of classical swine fever virus in vitro.
Autophagy plays an important role in cellular responses to pathogens. However, the impact of the autophagy machinery on classical swine fever virus (CSFV) infection is not yet confirmed. In this study, we showed that CSFV infection significantly increases the number of autophagy-like vesicles in the cytoplasm of host cells at the ultrastructural level. We also found the formation of 2 ubiquitin-like conjugation systems upon virus infection, including LC3-I/LC3-II conversion and ATG12-ATG5 conjugation, which are considered important indicators of autophagy. Meanwhile, high expression of ATG5 and BECN1 was detected in CSFV-infected cells; conversely, degradation of SQSTM1 was observed by immunoblotting, suggesting that CSFV infection triggered a complete autophagic response, most likely by the NS5A protein. Furthermore, by confocal immunofluorescence analysis, we discovered that both envelope protein E2 and nonstructural protein NS5A colocalized with LC3 and CD63 during CSFV infection. Examination by immunoelectron microscopy further confirmed the colocalization of both E2 and NS5A proteins with autophagosome-like vesicles, indicating that CSFV utilizes the membranes of these vesicles for replication. Finally, we demonstrated that alteration of cellular autophagy by autophagy regulators and shRNAs affects progeny virus production. Collectively, these findings provide strong evidence that CSFV infection needs an autophagy pathway to enhance viral replication and maturity in host cells.
['Pei|Jingjing|J|', 'Zhao|Mingqiu|M|', 'Ye|Zuodong|Z|', 'Gou|Hongchao|H|', 'Wang|Jiaying|J|', 'Yi|Lin|L|', 'Dong|Xiaoying|X|', 'Liu|Wenjun|W|', 'Luo|Yongwen|Y|', 'Liao|Ming|M|', 'Chen|Jinding|J|']
D000225:Adenine D000818:Animals D001343:Autophagy D015415:Biomarkers D002460:Cell Line D002470:Cell Survival D006691:Classical Swine Fever D006692:Classical Swine Fever Virus D007425:Intracellular Membranes D008565:Membrane Proteins D008869:Microtubule-Associated Proteins D010588:Phagosomes D034741:RNA, Small Interfering D012367:RNA, Viral D020123:Sirolimus D013552:Swine D014764:Viral Proteins D014779:Virus Replication
autophagy replication classical swine fever virus (CSFV) BECN1 LC3