Cholesterol is an essential component of
lipid rafts in cellular plasma membranes. Although
lipid rafts have been reported to have several functions in multiple stages of the life cycles of many different enveloped viruses, the mechanisms by which non-enveloped viruses, which lack outer
lipid membranes, infect host cells remain unclear. In this study, to investigate the dependence of non-enveloped avian reovirus (ARV)
infection on the integrity of
cholesterol-rich membrane rafts, methyl-β-
cyclodextrin (MβCD) was used to deplete cellular membrane
cholesterol at the ARV attachment, entry, and post-entry stages. Treatment with MβCD significantly inhibited ARV replication at both the entry and post-entry stages in a dose-dependent manner, but MβCD had a statistically insignificant effect when it was added at the attachment stage. Moreover, MβCD treatment markedly reduced syncytium formation, which occurs at a relatively late stage of the ARV life cycle and is involved in cell-cell transmission and release. Furthermore, the addition of exogenous
cholesterol reversed the effects mentioned above. Colocalization data also showed that the ARV
proteins σC, μNS, and p10 prefer to localize to
cholesterol-rich
lipid raft regions during ARV
infection. Altogether, these results suggest that cellular
cholesterol in
lipid rafts plays a critical role in ARV replication.