Characterisation of the signalling mechanisms involved in the induction of cyclooxygenase-2 by interleukin-4

Historically cyclooxygenase (COX)-2 has been associated with the pro-inflammatory phase of inflammation; recently there is evidence to suggest the protein also has an anti-inflammatory role. A number of research groups have given in vivo evidence showing inhibition of COX-2 in the late stages of the inflammatory response to exacerbate inflammation suggesting COX-2 to also play a pro-resolution role1. If proven, this phenomena may open new doors for research as this late phase COX-2 could be considered a target for the early resolution of inflammation. In comparison to lipopolysaccharide (LPS)-stimulated macrophages, we showed diclofenac induced COX-2 was associated with anti-inflammatory cytokine release and required activation of peroxisome proliferator-activated receptor-g (PPAR-g)2. In the current study, we sought to investigate a potential endogenous inducer for the PPAR-g-dependent COX-2 enzyme and to elucidate the molecular pathway associated with induction of this protein.