Lupeol inhibits LPS-induced NF-kappa B signaling in intestinal epithelial cells and macrophages, and attenuates acute and chronic murine colitis

Abstract

AimsLupeol, a natural pentacyclic triterpene, exhibits anti-inflammatory effects. However, its role in colitis has not been investigated. In the present study, we evaluated the effect of lupeol on the NF-κB signaling pathway and experimental colitis in mice. Main methodsThe human intestinal epithelial cells (IECs) COLO 205 and the murine macrophages RAW 264.7 were pretreated with lupeol and then stimulated with lipopolysaccharide (LPS). The production of inflammatory cytokines (IL-8 from COLO 205; IL-6, IL-12 and TNF-α from RAW 264.7) was determined by ELISA. The effect of lupeol on NF-κB pathway was examined by Western blot analysis of IκBα phosphorylation/degradation and an electrophoretic mobility shift assay (EMSA). For in vivo studies, dextran sulfate sodium (DSS)-induced acute colitis model and chronic colitis model in IL-10−/− mice were used. Colitis was quantified by disease activity index, colon length and histologic evaluation. Key findingsLupeol strongly suppressed pro-inflammatory cytokine production in IECs and murine macrophages. It also inhibited LPS-induced IκBα phosphorylation/degradation and the DNA binding activity of NF-κB. The oral administration of lupeol significantly reduced the colitis activity and histologic scores in both acute and chronic murine colitis models. Furthermore, the up-regulation of IκBα phosphorylation in the colonic mucosa was attenuated in lupeol-treated mice. SignificanceLupeol blocks the NF-κB signaling in IECs and murine macrophages, and attenuate experimental murine colitis. These findings suggest that lupeol is a potential therapeutic agent for inflammatory bowel disease.