15-Deoxy-△(12,14)-Prostaglandin J(2) Promotes Resolution of Experimentally Induced Colitis

Uncontrolled macrophage functions cause failure to resolve gut inflammation and has been implicated in the pathogenesis of inflammatory bowel disease (IBD). 15-Deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ(2)), one of endogenous lipid mediators formed from arachidonic acid during the inflammatory process, has been reported to terminate inflammation. However, the pro-resolving effect of 15d-PGJ(2) on intestinal inflammation and underlying molecular mechanisms remain largely unknown. In the present study, we examined the effects of 15d-PGJ(2) on the resolution of dextran sulfate sodium (DSS)-induced murine colitis that mimics human IBD. Pharmacologic inhibition of prostaglandin D synthase (PGDS) responsible for the synthesis of 15d-PGJ(2) hampered resolution of inflammation in the colonic mucosa of mice treated with DSS. Notably, intraperitoneal injection of 15d-PGJ(2) accelerated the resolution of experimentally induced colitis. 15d-PGJ(2) treatment reduced the number of neutrophils and M1 macrophages, while it increased the proportion of M2 macrophages. Moreover, 15d-PGJ(2) treated mice exhibited the significantly reduced proportion of macrophages expressing the pro-inflammatory cytokine, IL-6 with concomitant suppression of STAT3 phosphorylation in the colonic mucosa of mice administered 2.5% DSS in drinking water. Taken together, these findings clearly indicate that 15d-PGJ(2), endogenously generated from arachidonic acid by cyclooxygenase-2 and PGDS activities in inflamed tissue, promotes resolution of intestinal colitis.