AUTHOR=Ding Ning , Zhao Kui , Lan Yungang , Li Zi , Lv Xiaoling , Su Jingjing , Lu Huijun , Gao Feng , He Wenqi 

TITLE=Induction of Atypical Autophagy by Porcine Hemagglutinating Encephalomyelitis Virus Contributes to Viral Replication

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=Volume 7 - 2017

YEAR=2017

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2017.00056

DOI=10.3389/fcimb.2017.00056

ISSN=2235-2988

ABSTRACT=Autophagy is a cellular degradation process involving in intracellular membrane transport pathways that recycle cellular components and eliminate intracellular microorganisms within the lysosome. Autophagy also plays an important role in virus infection and propagation. However, some viruses have evolved unique strategies to escape or exploit autophagy. This study explores the mechanism of autophagy induction by porcine hemagglutinating encephalomyelitis virus (PHEV) in Neuro-2a cells, and examines the role of autophagy in PHEV replication. PHEV triggered autophagy in Neuro-2a cells is based on the appearance of abundant double- and single-membrane vesicles, the accumulation of LC3 fluorescent puncta, and the enhancement of LC3-I/II conversion. In addition, PHEV induced an incomplete autophagic effect because the degradation level of p62 did not change in PHEV-infected cells. Similar results were obtained using LysoTracker and lysosome-associated membrane protein by indirect immunofluorescence labeling in PHEV-infected cells. We also investigated the change in viral replication by pharmacological experiments with the autophagy inducer rapamycin or the autophagy inhibitor 3-MA, and the lysosomal inhibitor chloroquine (CQ). Compared with the mock treatment, inhibition of autophagy by 3-MA increased, whereas induction of autophagy by rapamycin reduced PHEV replication. CQ treatment increased the conversion of LC3-I to LC3-II in PHEV-infected Neuro-2a cells but decreased PHEV replication. These results show that PHEV infection induces atypical autophagy and causes the accumulation of autophagosomes but blocks the fusion of autophagosomes with lysosomes, which is necessary for the replication of PHEV in nerve cells.