Junín Virus Promotes Autophagy to Facilitate its Viral Life Cycle

ROLDAN, J. S.; DELGUI, L. R.; COLOMBO, M. I.; CANDURRA, N. A.

Mendoza

Simposio; Second International Symposium on Traslational Medicine; 2019

Junín virus (JUNV) is the etiological agent of the Argentine Haemorrhagic Fever (AHF), a potentially deadly, endemic-epidemic disease affecting the population of the most fertile farming land of Argentina. Autophagy is an intracellular degradative pathway with a crucial anti-viral role; however, several viruses subvert this pathway in their own benefit. We studied the role of autophagy in JUNV-infected cells analysing LC3, a cytoplasmic protein (LC3-I) which becomes vesicle membrane-associated (LC3-II) upon induction of autophagy. Cells overexpressing EGFP-LC3 and infected with JUNV showed an increased number of LC3 puncta structures, similar to that obtained after starvation- or Bafilomycin A1- treatment, which leads to autophagosome induction or accumulation, respectively. We also monitored the conversion of LC3-I to LC3-II by western blot analysis, observing LC3-II levels in JUNV-infected cells similar to that observed in starved cells. Additionally, we kinetically studied the conversion of LC3 after JUNV infection by confocal microscopy and western blot and found that the virus activated the pathway as early as 2 h p.i. whereas the UV-inactivated virus did not induce the pathway. Cells subjected to starvation or pre-treated with rapamycin, a pharmacological autophagy inductor, enhanced virus yield. In addition, we assayed the replication capacity of JUNV in Atg 5 knock-out or Beclin-1 knock-down cells both key components of the autophagic pathway and found a significant hamper of JUNV replication.Taken together, our results constitute the first study indicating that JUNV infection triggers the autophagic response, which is functionally required by the virus for its efficient propagation. Moreover, we showed, for a member of the Arenaviridae family, a pro-viral role of autophagy in JUNV infection, providing novel knowledge in the edge of host-virus interaction. Therefore, modulation of virus-induced autophagy could be used as a strategy to block arenaviruses infections.