Schisandra Chinensis Lignans Suppresses the Production of Inflammatory Mediators Regulated by NF-κB, AP-1, and IRF3 in Lipopolysaccharide-Stimulated RAW264.7 Cells

Abstract

Schisandra Fructus (SF) is a traditional Chinese herb used in the treatment of inflammatory disorders like hepatitis. One of the main anti-inflammatory components of SF is the lignans. However, the underlying anti-inflammatory mechanism of Schisandra Chinensis lignans (SCL) remains unclear. This study aims to investigate the effects of SCL on inflammatory mediators in lipopolysaccharide-stimulated RAW264.7 cells and explore the underlying mechanism. The production of nitric oxide (NO) was determined by Griess reaction. ELISA was used to determine cytokine levels and chemokines secretion. To estimate protein levels and enzyme activities, we employed Western blotting. Nuclear localization of NF-κB, AP-1, and IRF3 was detected using immunofluorescence analyses. The results showed that SCL significantly reduced the release of inflammatory mediators, including NO and PGE2, which may be related to down-regulation of iNOS and COX-2 expression. The production of cytokines and chemokines was suppressed by SCL treatment. SCL also decreased the phosphorylation of IKKα/β, IκB-α, Akt, TBK1, ERK, p38, JNK, NF-κB (p65), AP-1 (c-Jun), and IRF3 in RAW264.7 macrophages activated with LPS. The nuclear protein levels and nuclear translocation of AP-1, NF-κB and IRF3 were suppressed by SCL. These results indicated that SCL suppressed the IKKα/β/NF-κB, MAPKs/AP-1 and TBK1/IRF3 signaling pathways in LPS-stimulated RAW264.7 macrophages.

Re-Du-Ning inhalation solution exerts suppressive effect on the secretion of inflammatory mediators via inhibiting IKKα/β/IκBα/NF-κB, MAPKs/AP-1, and TBK1/IRF3 signaling pathways in lipopolysaccharide stimulated RAW 264.7 macrophages

“…It has been reported that LPS activates the TLR4 signaling pathway and subsequently produces pro-inammatory cytokines and chemokines in the macrophage cells. 15,26,27 In line with the previous studies, we observed that LPS remarkably promoted the release of pro-inammatory cytokines (see Following LPS stimulation, NF-kB, AP-1, and IRF3 are activated by post-translational modications, and translocate into the nucleus to induce the transcription of the pro-inammatory cytokines and chemokines. 28,29 Therefore, we rstly investigated the nuclear translocation of these three transcription factors by Western blot analysis.…”

“…47 TBK1 can phosphorylate IRF3 and promotes it nuclear translocation, leading to the expression of IFN-b and CCL-5. 27 Our data represent that the nuclear and phosphorylation levels of IRF3 as well as the phosphorylated TBK1 were decreased by the RIS treatment, indicating that RIS impeded the LPS-induced TBK1/IRF3 axis.…”

“…Effect of RIS on the IKKa/b/IkBa/NF-kB, MAPKs/AP-1, and TBK1/IRF3 signaling pathways LPS binds to TLR4 and leads to the activation of NF-kB, AP-1, and IRF3 through the recruitment and activation of the upstream proteins. 24,27 Therefore, we examined the expression of molecular components of TLR4 related pathways in the RAW 264.7 cells. As shown in Fig.…”

Xiao Qing Long Tang essential oil exhibits inhibitory effects on the release of pro-inflammatory mediators by suppressing NF-κB, AP-1, and IRF3 signalling in the lipopolysaccharide-stimulated RAW264.7 cells

“…Subsequently, the secretion of these cytokines and chemokines were increased, which was necessary to activate the inammatory response. 23 To examine the inhibitory effect of XQEO on the gene expression of pro-inammatory cytokines Effects of the XQEO on the LPS-induced overproduction of pro-inammatory cytokines and chemokines in the RAW264.7 macrophages…”

“…The nuclear translocation of transcription factors, such as NF-kB, AP-1, and IRF3, is considered a prerequisite for the transcription of genes associated with inammatory processes. 23 Therefore, in the present study, we also explored the effect of XQEO on the nuclear translocation of these transcription factors in the RAW264.7 cells. As shown in Fig.…”