Foot-and-mouth disease virus degrades Rab27a to suppress the exosome-mediated antiviral immune response.

Foot-and-mouth disease (FMD) is a highly contagious infection caused by foot-and-mouth disease virus (FMDV). Exosomes are extracellular vesicles that mediate antiviral immune responses in host cells and could be used by pathogens to evade host cell immune responses. Whether FMDV affects exosome secretion or whether exosomes derived from FMDV-infected cells mediate host cell antiviral immune responses is not yet clarified. In this study, the exosomes were identified and extracted from FMDV-infected PK-15 cells, and it was found that FMDV inhibits exosome secretion. Further investigation revealed that FMDV suppresses exosomes by degrading Rab27a via the autophagy-lysosome pathway. Also, microRNA (miRNA) differential analysis was performed in exosomes, which revealed that miRNA-136 was highly differentially expressed in exosomes and may be the key miRNA that inhibits the proliferation of FMDV. In summary, these results showed that host cells take advantage of exosomes to mediate their antiviral immune response, while FMDV evades exosome-mediated immune responses by degrading the exosome molecular switch, Rab27a.