Sindbis virus is suppressed in the yellow fever mosquito Aedes aegypti by Atg6/BECN1 (autophagy-related 6)-mediated activation of autophagy

Macroautophagy/autophagy is a critical modulator of pathogen invasion response in vertebrates and invertebrates. However, how it affects mosquito-borne viral pathogens that significantly burden public health remains relatively underexplored. To address this gap, we use a genetic approach to activate autophagy in the yellow fever mosquito (Aedes aegypti) infected with a recombinant Sindbis virus (SINV) expressing an autophagy activator. We first demonstrate a 17-amino acid peptide (“AaBec-1”) derived from the Ae. aegypti Atg6/BECN1 (Autophagy-related 6) gene is sufficient to induce autophagy in C6/36 mosquito cells, as marked by lipidation of Atg8 and puncta formation. Next, we engineered a recombinant SINV expressing the AaBec-1 peptide and used it to infect and induce autophagy in adult mosquitoes. We find that modulation of autophagy using this recombinant SINV negatively regulates production of infectious virus. The results from this study improve our understanding of the role of autophagy in regulating arbovirus infection in invertebrate hosts and highlight the potential for the autophagy pathway to be exploited for arbovirus control. Abberviation: C6/36– Aedesalbopictuscell line; dpi–days post-infection; FFA–focus-forming assay;MOI–multiplicity of infection; MTOR–Mechanistic target ofrapamycin kinase; PBS–phosphate-buffered saline; PCR–polymerase chain reaction; RT-PCR–reversetranscription-polymerase chain reaction; RNA–ribonucleic acid;SINV–Sindbis virus; Vero–African green monkey kidneyepithelial cells.