title: Coxsackievirus B3 infection induces autophagic flux, and autophagosomes are critical for efficient viral replication.
abstract: Autophagy is an intrinsic cellular process that can degrade cytoplasmic components. It has been reported that several pathogens hijack this process to facilitate their replication. Coxsackievirus B3 (CVB3), a member of the family Picornaviridae, induces autophagy upon infection. However, the details of CVB3-induced autophagy remain a subject of debate. This study applied a combination of multiple assays for the measurement of autophagy and demonstrated that CVB3 induces a complete autophagic flux. Experiments with infected HEK293A cells revealed that autophagosomes were induced upon CVB3 infection. Most of these autophagosomes were mCherry positive in mCherry-GFP-LC3 cells. Conversely, mCherry-positive autophagosomes were rescued to green positive when treated with the acidification inhibitors chloroquine (CQ) and bafilomycin A1 (BAF), suggesting that autophagosomes fused with late endosomes or lysosomes. The co-localization of LC3-positive puncta with lysosome-associated membrane protein 1 (LAMP1) or LysoTracker confirmed that the autophagosomes fused primarily with lysosomes. Interestingly, the disruption of autophagosome formation by 3-methyladenine (3-MA) or ATG5 siRNA treatment during viral infection significantly decreased CVB3 replication. However, inhibitors of lysosomal acidification, fusion, or degradation did not affect viral replication. Therefore, autolysosomes may not be critical for viral replication in vitro.
authors.affiliation: Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, People's Republic of China.
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Shi
authors.affiliation: Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, People's Republic of China.
authors.forename: Zijian
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, People's Republic of China.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Tang
authors.affiliation: Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wu
authors.affiliation: Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, People's Republic of China. sdxiongfd@126.com.
authors.forename: Sidong
authors.initials: S
authors.lastname: Xiong
authors.affiliation: Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, People's Republic of China. chunshengdong@suda.edu.cn.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Dong
mesh_terms: D000071182:Autophagosomes / Q000378:metabolism / Q000821:virology*; D001343:Autophagy; D003384:Coxsackievirus Infections / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology* / Q000821:virology; D029822:Enterovirus B, Human / Q000235:genetics / Q000502:physiology*; D057809:HEK293 Cells; D006801:Humans; D052118:Lysosomal-Associated Membrane Protein 1 / Q000235:genetics / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism / Q000821:virology; D014779:Virus Replication
chemical_list: D052118:Lysosomal-Associated Membrane Protein 1