Exosomes are 30-150 nm small membrane vesicles that are released into the extracellular medium via cells that function as a mode of intercellular communication. Dendritic cell (DC)-derived exosomes modulate immune responses and prevent the development of
autoimmune diseases. Moreover, Schistosoma japonicum eggs show modulatory effects in a mouse model of
colitis. Therefore, we hypothesized that exosomes derived from DCs treated with S. japonicum soluble eggs
antigen (SEA; SEA-treated DC exosomes) would be useful for treating
inflammatory bowel disease (IBD). Exosomes were purified from the supernatant of DCs treated or untreated with SEA and identified via transmission electron microscopy, western blotting and NanoSight. Acute
colitis was induced via the administration of
dextran sulfate sodium (DSS) in
drinking water (5.0%, wt/vol). Treatment with exosomes was conducted via
intraperitoneal injection (i.p.; 50 μg per mouse) from day 0 to day 6. Clinical scores were calculated based on
weight loss, stool type, and
bleeding. Colon length was measured as an indirect marker of
inflammation, and colon macroscopic characteristics were determined.
Body weight loss and the disease activity index of DSS-induced
colitis mice decreased significantly following treatment with SEA-treated DC exosomes. Moreover, the colon lengths of SEA-treated DC exosomes treated
colitis mice improved, and their mean colon macroscopic scores decreased. In addition, histologic examinations and histological scores showed that SEA-treated DC exosomes prevented colon damage in acute DSS-induced
colitis mice. These results indicate that SEA-treated DC exosomes attenuate the severity of acute DSS-induced
colitis mice more effectively than DC exosomes. The current work suggests that SEA-treated DC exosomes may be useful as a new approach to treat IBD.