Abstract
The protective effects of G protein-coupled receptor 39 (GPR39) on concanavalin A (Con A)-induced hepatitis in mice was examined. In a dose dependent manner and at 24 h after the elicitation by Con A, oral administration of TC-G 1008, a GPR39 agonist, reduced both, the glutamic-pyruvic transaminase levels (a marker for liver injury) and the necrosis area, as revealed by the histological analysis of tissues from mice with Con A-induced hepatitis. TC-G 1008 also suppressed serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α significantly at 6 h after the elicitation, suggesting that the cells producing IL-6 and/or TNF-α are the targets of TC-G 1008. One potential target cell appears to be a monocyte-derived macrophages because TC-G 1008 treatment suppressed lipopolysaccharide-induced IL-6 production from U937 macrophages in vitro. Taken together, GPR39 agonist TC-G 1008 ameliorates liver injury in the Con A model by blocking pro-inflammatory cytokine production. Use of GPR39 agonists for monotherapy or in combination with immunosuppressants might prove to be beneficial in the treatment of autoimmune hepatitis.
