Chemerin is characterized by a chemoattractant protein present in various inflammatory sites. Several studies have suggested that chemerin plays an anti-inflammatory role in acute tissue inflammation by inhibiting the recruitment of inflammatory cells. It has been recently reported that chemerin is elevated in patients with inflammatory bowel disease (IBD), however, the role of chemerin in IBD remains unknown. In the present study, we examined a role for chemerin in the development DSS-induced experimental colitis. Chemerin expression was up-regulated on days 5 and 8 after continuous DSS exposure for 5 days. Administration of exogenous chemerin aggravated the severity of DSS-induced colitis, which was characterized by more severe clinical disease scores, extensive epithelial damage and significantly increased expression of inflammatory cytokines in the colon on days 5 and 8. The exacerbated colitis was associated with decreased early colonic infiltration of neutrophils and decreased colonic expression of M2 macrophage-associated genes. In vitro study further demonstrated that chemerin negatively regulated IL-4-induced M2 macrophage polarization from the peritoneal macrophages. Our results suggest that chemerin plays an inflammatory role in DSS-induced colitis by impairing the protective innate responses and the targeting of chemerin for anti-inflammatory treatment should be cautious.
- Copyright © 2013 by The American Association of Immunologists, Inc.