Anti-inflammatory effects of 6-formyl umbelliferone via the NF-?B and ERK/MAPK pathway on LPS-stimulated RAW 264.7 cells

Abstract

Inhibition of over-activated inflammation has been demonstrated as one of the most efficient strategies for treating inflammatory diseases. In the present study, 6-formyl umbelliferone (6FU) was used to evaluate its anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. 6FU inhibited chronic inflammatory processes, including increasing nitric oxide levels, and the expression of pro-inflammatory genes and producing cytokines was investigated by a nitrite assay and reverse transcription-polymerase chain reaction, respectively. Nitric oxide and pro-inflammatory cytokines, including tumor necrosis factor-a, interleukin (IL)-1ß a nd I L-6 were d ecreased by t reatment w ith 6 FU, without cell cytotoxicity in LPS-stimulated RAW 264.7 cells, which was measured by a WST-1 assay. In the western blot analysis, the expression levels of phosphorylated extracellular signal-regulated kinase (ERK)1/2 was downregulated in 6FU-treated cells. Furthermore, in the western blotting and immunofluorescence staining results, translocation activities of ERK1/2 and NF-?B from the cytoplasm to the nucleus were suppressed, which may inhibit translation of numerous proteins associated with pro-inflammation, including inducible nitric oxide synthase and cyclooxygenase-2. Therefore, based on these results, it was suggested that 6FU may be a potential candidate for the development of agents against chronic inflammation.