We have demonstrated that R()WIN55,212-2, a synthetic cannabinoid that possesses cannabimimetic properties, acts as a novel regulator of Toll-like receptor 3 (TLR3) signaling to interferon (IFN) regulatory factor 3 (IRF3) activation and IFN- expression, and this is critical for manifesting its protective effects in a murine multiple sclerosis model. Here we investigated the role of peroxisome proliferator-activated receptor- (PPAR) in mediating the effects of R()WIN55,212-2 on this pathway. Data herein demonstrate that the TLR3 agonist poly(I:C) promotes IFN- expression and R()WIN55,212-2 enhances TLR3-induced IFN- expression in a stereoselective manner via PPAR. R()WIN55,212-2 promotes increased transactivation and expression of PPAR. Using the PPAR antagonist GW6471, we demonstrate that R()WIN55,212-2 acts via PPAR to activate JNK, activator protein-1, and positive regulatory domain IV to transcriptionally regulate the IFN- promoter. Furthermore, GW6471 ameliorated the protective effects of R()WIN55,212-2 during the initial phase of experimental autoimmune encephalomyelitis. Overall, these findings define PPAR as an important mediator in manifesting the effects of R()WIN55,212-2 on the signaling cascade regulating IFN- expression. The study adds to our molecular appreciation of potential therapeutic effects of R()WIN55,212-2 in multiple sclerosis.