TNF-α and INF-γ primed canine stem cell-derived extracellular vesicles alleviate experimental murine colitis.

The inflammatory bowel diseases (IBD) are characterized by relapsing inflammation and immune activation diseases of the gastrointestinal tract. Extracellular vesicles, which elicit similar biological activity to the stem cell themselves, have been used experimentally to treat dextran sulfate sodium (DSS)-induced colitis in murine models though immunosuppressive potential. In this study, we investigated whether the Extracellular vesicles (EVs) obtained by stimulating inflammatory cytokine on canine adipose mesenchymal stem cells (cASC) improved anti-inflammatory and/or immunosuppressive potential of EVs, and/or their ability to alleviate inflammation in colitis. We also explored the correlation between immune cells and the inflammatory repressive effect of primed EVs. Pro-inflammatory cytokines such as TNF-α and IFN-γ increased immunosuppressive protein such as HGF, TSG-6, PGE2 and TGF-β in EVs. Moreover, the anti-inflammatory effect of EVs was improved through pretreatment with inflammatory cytokines. Importantly, EVs obtained from primed stem cells effectively induced macrophage polarization toward an anti-inflammatory M2 phenotype and suppressed activated immunity by enhancing regulatory T cells in inflamed colon in mice. Our results provide a new and effective therapy for the EVs obtained from ASC stimulated with TNF-α and IFN-γ against not only IBD, but also immune-mediated disease.