TY  - JOUR
AU  - Metz, Philippe
AU  - Chiramel, Abhilash
AU  - Chatel-Chaix, Laurent
AU  - Alvisi, Gualtiero
AU  - Bankhead, Peter
AU  - Mora-Rodriguez, Rodrigo
AU  - Long, Gang
AU  - Hamacher-Brady, Anne
AU  - Brady, Nathan R
AU  - Bartenschlager, Ralf
TI  - Dengue Virus Inhibition of Autophagic Flux and Dependency of Viral Replication on Proteasomal Degradation of the Autophagy Receptor p62.
JO  - Journal of virology
VL  - 89
IS  - 15
SN  - 1098-5514
CY  - Baltimore, Md.
PB  - Soc.
M1  - DKFZ-2017-03152
SP  - 8026 - 8041
PY  - 2015
AB  - Autophagic flux involves formation of autophagosomes and their degradation by lysosomes. Autophagy can either promote or restrict viral replication. In the case of Dengue virus (DENV), several studies report that autophagy supports the viral replication cycle, and describe an increase of autophagic vesicles (AVs) following infection. However, it is unknown how autophagic flux is altered to result in increased AVs. To address this question and gain insight into the role of autophagy during DENV infection, we established an unbiased, image-based flow cytometry approach to quantify autophagic flux under normal growth conditions and in response to activation by nutrient deprivation or them TOR inhibitor Torin1.We found that DENV induced an initial activation of autophagic flux, followed by inhibition of general and specific autophagy. Early after infection, basal and activated autophagic flux was enhanced. However, during established replication, basal and Torin1-activated autophagic flux was blocked, while autophagic flux activated by nutrient deprivation was reduced, indicating a block to AV formation and reduced AV degradation capacity. During late infection AV levels increased as a result of inefficient fusion of autophagosomes with lysosomes. In addition, endolysosomal trafficking was suppressed, while lysosomal activities were increased.We further determined that DENV infection progressively reduced levels of the autophagy receptor SQSTM1/p62 via proteasomal degradation. Importantly, stable overexpression of p62 significantly suppressed DENV replication, suggesting a novel role for p62 as a viral restriction factor. Overall, our findings indicate that in the course of DENV infection, autophagy shifts from a supporting to an antiviral role, which is countered by DENV.Autophagic flux is a dynamic process starting with the formation of autophagosomes and ending with their degradation after fusion with lysosomes. Autophagy impacts the replication cycle of many viruses. However, thus far the dynamics of autophagy in case of Dengue virus (DENV) infections has not been systematically quantified. Therefore, we used high-content, imaging-based flow cytometry to quantify autophagic flux and endolysosomal trafficking in response to DENV infection. We report that DENV induced an initial activation of autophagic flux, followed by inhibition of general and specific autophagy. Further, lysosomal activity was increased, but endolysosomal trafficking was suppressed confirming the block of autophagic flux. Importantly, we provide evidence that p62, an autophagy receptor, restrict DENV replication and was specifically depleted in DENV-infected cells via increased proteasomal degradation. These results suggest that during DENV infection autophagy shifts from a proviral to an antiviral cellular process, which is counteracted by the virus.
KW  - Adaptor Proteins, Signal Transducing (NLM Chemicals)
KW  - SQSTM1 protein, human (NLM Chemicals)
KW  - Sequestosome-1 Protein (NLM Chemicals)
LB  - PUB:(DE-HGF)16
C6  - pmid:26018155
C2  - pmc:PMC4505648
DO  - DOI:10.1128/JVI.00787-15
UR  - https://inrepo02.dkfz.de/record/127126
ER  -