Figure of PPRV-induced reduction of Rab7 facilitates exosomes-mediated virus intercellular transmission via blocking MVBs degradation

Peste des petits ruminants virus (PPRV) is a significant pathogen that has a major impact on small ruminant productivity all over the world. Our prior research has shown that PPRV infection boosts the release of exosomes, which facilitates exosome-mediated viral replication. However, the regulatory mechanism of exosome biogenesis during virus infection remains largely unexplored. Here, we demonstrate that PPRV infection suppresses Rab7 expression, which inhibits multivesicular bodies (MVBs) from fusing with lysosomes and keeps intraluminal vesicles (ILVs) wrapped in MVBs from being degraded by lysosomes. Meanwhile, PPRV infection increases Rab27a expression in cells, which promotes the fusion of MVBs with the plasma membrane, and facilitates the secretion of ILVs carried viral infection components as exosomes. Taken together, our findings identify the mechanism by which PPRV promotes exosome secretion levels through the late endosomal maturation pathway and enhances viral infection by engaging the exosome pathway.