JUNV virus exploits host's cellular autophagy machinery

ARRÍAS, PAULA N.; ROMANOWSKI, VICTOR; GOMEZ, RICARDO M.; PEREZ VIDAKOVICS, MARIA LAURA A.; URE, AGUSTÍN E.; ARRÍAS, PAULA N.; GOMEZ, RICARDO M.; URE, AGUSTÍN E.; ROMANOWSKI, VICTOR; PEREZ VIDAKOVICS, MARIA LAURA A.

Madison, Wisconsin

Congreso; 36th Anual Meeting American Society for Virology; 2017

The American Society for Virology

As an integral part of the immune system, autophagy participates in virus detection and induction of antiviral defenses. Viruses have developed strategies that directly or indirectly alter autophagy and promote various stages of the viral cycle. Arenaviruses are enveloped viruses with two segments of an ambisense single-stranded RNA genome. Some of these viruses cause severe hemorrhagic fever in humans, including the New World arenavirus Junin virus (JUNV). JUNV, classified as a category A priority pathogen, is the causative agent of the Argentine hemorrhagic fever (AHF). There are currently no FDA-approved vaccines to prevent AHF. Recent studies suggest that arenaviruses can takeover host autophagic machinery to promote viral replication and budding. In individuals with AHF, the severity and prognosis of the disease correlates with high levels of IFN. The crosstalk between the IFN response and autophagic machinery would impact viral replication. In the present study, we investigated the role of autophagy in JUNV replication. We have observed that JUNV infection significantly enhanced accumulation of LC3-positive punctate pattern (a hallmarks of cellular autophagosome formation) in human A549 cells transfected with a RFP-LC3 plasmid. Protein samples from experiments performed in parallel and analyzed by Western blot showed an increase of the LC3-II/LC3-I ratio in cells infected with JUNV after 24 h post-infection. We also found that inhibition of autophagy with Bafilomicin A1, Chloroquine or 3-Methyladenine reduce virus replication. Conversely, induction of autophagy by treatment of A549 cells with rapamycin or nutrient deprivation resulted in increased JUNV replication. Finally, we observed that siRNA targeting key autophagy genes (Atg5, Atg7, Beclin1) altered JUNV replication. Our results suggest that the host´s autophagy machinery is activated during JUNV infection to enhance the efficiency of viral replication. Studying and understanding these mechanisms will enable the development of preventive and therapeutic strategies against HFA and other arenaviral hemorrhagic fevers.p { margin-bottom: 0.1in; line-height: 120%; }a:link { }Asan integral part of the immune system,autophagy participates in virus detection and induction of antiviraldefenses. Viruseshave developed strategies that directly or indirectly alter autophagyand promote various stages of the viral cycle. Arenaviruses areenveloped viruses with two segments of an ambisense single-strandedRNA genome. Some of these viruses cause severehemorrhagic fever in humans, including the New World arenavirus Juninvirus (JUNV). JUNV,classifiedas a category A priority pathogen,isthecausative agent of the Argentinehemorrhagic fever (AHF).Thereare currently no FDA-approvedvaccines to prevent AHF.Recentstudies suggest that arenaviruses can takeoverhostautophagicmachinerytopromote viral replication and budding. In individuals with AHF,the severityandprognosis of the disease correlates with high levels of IFN. Thecrosstalkbetweenthe IFNresponse and autophagicmachinery wouldimpactviral replication. Inthe present study, we investigated the role of autophagy in JUNVreplication. Wehave observed that JUNV infection significantlyenhanced accumulationof LC3-positivepunctatepattern (ahallmarks of cellular autophagosome formation)in human A549 cells transfected with a RFP-LC3 plasmid. Proteinsamples from experiments performed in parallel and analyzed byWestern blot showed an increase of the LC3-II/LC3-I ratio in cellsinfected with JUNV after 24 h post-infection. Wealsofound thatinhibitionof autophagywith BafilomicinA1, Chloroquineor 3-Methyladeninereduce virus replication.Conversely, induction of autophagy by treatmentof A549 cells with rapamycinor nutrient deprivation resulted in increased JUNVreplication. Finally,we observed that siRNAtargeting keyautophagy genes(Atg5,Atg7,Beclin1)alteredJUNVreplication.Ourresults suggest that the host´s autophagy machinery is activatedduring JUNV infection to enhance the efficiency of viral replication.Studyingand understanding these mechanisms will enable the development ofpreventive and therapeutic strategies against HFA and otherarenaviralhemorrhagic fever