The intestinal anti-inflammatory effects of the novel agent UR-1505 in the TNBS model of rat colitis are mediated by T-lymphocyte inhibition

UR-1505 is a novel pentafluoropropoxy derivative of salicylic acid, selected from a series of salicylate derivatives, according to their activity as inhibitors of T-lymphocyte activation. This study describes the anti-inflammatory activity of UR-1505 on trinitrobenzenesulphonic acid-induced colitis in rat, an experimental model that resembles to Crohn's disease (CD), as well as its in vitro effects on T-cells and bone marrow-derived macrophages (BMDM) activation. UR-1505 showed intestinal anti-inflammatory effect, associated with reduced colonic levels of TNFα and LTB4, inhibition of the expression of IFNγ and iNOS, and lower colonic leukocyte infiltration. The in vitro assays revealed that UR-1505 also inhibited T-lymphocyte proliferation and IL-12/IFNγ production, two of the main pro-inflammatory cytokines involved in the pathogenesis of CD. However, UR-1505 did not modify LPS- nor IFNγ-induced activation in BMDM. Thus, UR-1505 specifically affects T-cells without modifying the activation of BMDM. In conclusion, the intestinal anti-inflammatory activity of UR-1505 seems to be mediated by a reduction in the recruitment of immune cells to the inflammatory foci, together with the inhibition of T-cell activation. These results suggest that UR-1505 may be an interesting candidate to be explored for the treatment of CD.