Journal Article

The effects of autophagy on the replication of Nelson Bay orthoreovirus

Hong-Yan Zhao, Xiaoli Tao, Yibo Zhang, Xiaofang Wang, Wei Tong, Nian Liu, Lili Dou, Wei Zhao, Xu-Peng Jin, Ying Lu, Hong Jin, Yanfei Shen, Yonggang Li, Jiangman Chen

2019

Overview

Background Nelson Bay orthoreovirus (NBV) was first isolated over 40 years ago from a fruit bat in Australia. Normally, NBV does not cause human diseases, but recently several NBV strains have been associated with human respiratory tract infections, thus attracting clinical attention. Autophagy, an evolutionarily conserved process in eukaryotic cells, degrades intracellular substrates, participates in multiple physiological processes, and maintains cellular homeostasis. In addition, autophagy is intimately involved in viral infection. Methods A new strain of NBV, isolated from a patient with a respiratory tract infection who returned to Japan from Bali, Indonesia, in 2007, was used in this study. NBV was rescued using a reverse genetics system involving cotransfection of BHK cells with 11 plasmids (pT7-L1 MB, pT7-L2 MB, pT7-L3 MB, pT7-M1 MB, pT7-M2 MB, pT7-M3 MB, pT7-S1 MB, pT7-S2 MB, pT7-S3 MB, pT7-S4 MB, and pcDNA3.1-T7), yielding NBV-MB. Recovered viruses were confirmed by immunofluorescence. The effect of NBV-MB on autophagy was evaluated by measuring the LC3-I/II proteins by immunoblot analysis after infection of BHK cells. Furthermore, after treatment with rapamycin (RAPA), 3-methyladenine (3-MA), chloroquine (CQ), or plasmid (GFP-LC3) transfection, the changes in expression of the LC3 gene and the amount of LC3-I/II protein were examined. In addition, variations in viral titer were assayed after treatment of BHK cells with drugs or after transfection with plasmids pCAGM3 and pCAGS3, which encode virus nonstructural proteins μNS and σNS, respectively. Results NBV-MB infection induced autophagy in host cells; however, the level of induction was dependent on viral replication. Induction of autophagy increased viral replication. By contrast, inhibiting autophagy suppressed NBV replication, albeit not significantly. The NBV-MB nonstructural protein μNS was involved in the induction of autophagy with viral infection. Conclusions NBV-MB infection triggered autophagy. Also, the NBV nonstructural protein μNS may contribute to augmentation of autophagy upon viral infection.

• Publisher: Springer Science and Business Media LLC,BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Apoptosis / Australia / Autophagy / Autophagy (Cytology) / Bats (Animals) / Biomedical and Life Sciences / Biomedicine / Cell Line / Chiroptera / Chloroquine / Development and progression / drugs / eukaryotic cells / Fluorescent antibody technique / Genes / Genetics / HEK293 Cells / Hepatitis / Homeostasis / Host Microbial Interactions / human diseases / Humans / Immunofluorescence / Indonesia / Infection / Infections / Infectious and parasitic diseases / Japan / Kinases / Mammals / Nelson Bay / Nelson Bay orthoreovirus / Nonstructural proteins / Orthoreovirus / Orthoreovirus - physiology / Orthoreovirus replication / Other viruses (e.g. pox / papilloma / parvo / Pathogenesis / patients / Phagocytosis / Physiological aspects / Plasmids / Proteins / Rapamycin / RC109-216 / reoviridae / Reoviridae Infections / Reoviridae Infections - virology / Reoviruses / Replication / Respiratory tract diseases / Reverse Genetics / Transfection / Viral infections / Viral Load / viral nonstructural proteins / Viral Proteins / Viral Proteins - genetics / Virology / Virus diseases / Virus Replication / Viruses / West Nile virus / μNS