Background: Triggering receptor expressed on myeloid cells (TREM)-1 constitutively expressed in macrophage, and upregulated by bacterial components, such as lipopolysaccharide (LPS), and functions as an amplifying molecule in infi ammatory responses. ...
Background: Triggering receptor expressed on myeloid cells (TREM)-1 constitutively expressed in macrophage, and upregulated by bacterial components, such as lipopolysaccharide (LPS), and functions as an amplifying molecule in infi ammatory responses. Recent studies have reported that TREM-1 expression is up-regulated in patients with infi ammatory bowel disease (IBD). In this study, we expected that guggulsterone (GGS) functions as reducer of TREM-1 in macrophage and investigated the anti-infi ammatory effects of GGS via the inhibition of NF-κB/TREM-1 in mononuclear cells using RAW264.7 activated by LPS and TNBS-induced colitis model of knockout mice. Methods: We are checked the mRNA level of TREM-1 and toll like receptor 4 (TLR4) using real time RT-PCR and the protein level of IκBa and phospho-IκBa using western blotting and ELISA, and nuclear translocation of NF-κB using immunofi uorescence. MG132 and TREM-1 antibody were used to determine the interaction of NF-κ B and TREM-1 signaling. Mouse colitis is induced by the administration of TNBS into the colon. Results: GGS treatment decreased the mRNA and protein levels of TREM-1, TLR4, TNF-a, IL-6, IL17, COX-2, and MMP-9 by blocking the phosphorylation and degradation of IκBa as well as nuclear translocation of NF-κB in RAW264.7 macrophage activated by LPS. In the TNBS-induced colitis model, GGS reduced disease activity index (DAI), and infi ammation related protein expressions by suppressing NF-κB and TREM- 1 activation in colon mucosa. Conclusions: GGS blocks the NF-κB signaling pathway by targeting the TREM-1 in RAW264.7 macrophage activated by LPS and TNBS-induced mouse colitis model. Ourresults provide an insight into the mutual relationship NF-κB and TREM-1 signaling pathway. Eventually, these fi ndings shows that GGS has a anti-infi ammatory effects in macrophage cells through the regulation of the TREM-1 and NF-κB signaling, which suggests that GGS is a potential therapeutic agent for the treatment of IBD.