Anti-Inflammatory and Antioxidant Actions of N-Arachidonoyl Serotonin in RAW264.7 Cells.

The purpose of this study is to evaluate the effect of N-arachidonoyl serotonin (NA-5HT) on inflammatory response or oxidative stress in RAW264.7 cells exposed to lipopolysaccharide (LPS). When RAW264.7 cells were pre-incubated with NA-5HT before LPS treatment, NA-5HT was found to suppress LPS-induced formation of nitric oxide (NO), tumor necrosis factor-α or interleukins as well as expression of inducible NO synthase and cyclooxygenase-2 at non-cytotoxic concentrations. Consistent with this, NA-5HT efficiently reversed LPS-induced phosphorylative activation of nuclear factor-κB pathway probably through the suppression of mitogen-activated protein kinases (MAPKs) pathway or phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. Separately, NA-5HT enhanced the antioxidant capacity accompanied by nuclear translocation of nuclear factor-E2-related factor-2 (Nrf2) in RAW264.7 cells. Additionally, NA-5HT-induced nuclear translocation of Nrf2 was suppressed significantly by the inhibition of c-Jun N-terminal kinase1/2 or PI3K/Akt pathways, although NA-5HT phosphorylated signal molecules in MAPKs and PI3K/Akt pathways. Taken together, NA-5HT is proposed to exert anti-inflammatory and antioxidant actions in RAW264.7 cells.