Resveratrol inhibits LPS‑induced inflammation through suppressing the signaling cascades of TLR4‑NF‑κB/MAPKs/IRF3

Abstract

Resveratrol (Res) is a natural compound that possesses anti-inflammatory properties. However, the protective molecular mechanisms of Res against lipopolysaccharide (LPS)-induced inflammation have not been fully studied. In the present study, RAW264.7 cells were stimulated with LPS in the presence or absence of Res, and the subsequent modifications to the LPS-induced signaling pathways caused by Res treatment were examined. It was identified that Res decreased the mRNA levels of Toll-like receptor 4 (TLR4), myeloid differentiation primary response protein MyD88, TIR domain-containing adapter molecule 2, which suggested that Res may inhibit the activation of the TLR4 signaling pathway. It suppressed the expression levels of total and phosphorylated TLR4, NF-κB inhibitor, p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase, extracellular signal-regulated kinase 1/2 and interferon (IFN) regulatory factor 3 (IRF3) proteins. Following treatment with Res or specific inhibitors, the production of pro-inflammatory mediators including tumor necrosis factor-α, interleukin (IL)-6, IL-8 and IFN-β were decreased and the expression of anti-inflammatory mediator IL-10 was increased. These results suggested that Res may inhibit the signaling cascades of NF-κB, MAPKs and IRF3, which modulate pro-inflammatory cytokines. In conclusion, Res exhibited a therapeutic effect on LPS-induced inflammation through suppression of the TLR4-NF-κB/MAPKs/IRF3 signaling cascades.

A Highly Selective In Vitro JNK3 Inhibitor, FMU200, Restores Mitochondrial Membrane Potential and Reduces Oxidative Stress and Apoptosis in SH-SY5Y Cells

“…The cytotoxicity of different concentrations of LPS was evaluated in RAW264.7 cells by Tong et al According to their results, LPS at a maximum concentration of 1.25 µg/mL was not cytotoxic, (which provides support for the LPS concentration we used) and cytokine release (TNF-α and IL-6) was dose-dependent to LPS concentration. In this case, it should be mentioned that in our study cells were pretreated with LPS at higher concentrations compared to other studies (1 µg/mL vs. 0.5 µg/mL [ 103 , 106 ] vs. 0.1 µg/mL [ 104 , 105 ]. Furthermore, in these studies, LPS-stimulated RAW264.7 cells were exposed to concentrations of SP600125 of 10 µM [ 103 , 106 ] and 20 µM [ 104 ].…”

“…In this case, it should be mentioned that in our study cells were pretreated with LPS at higher concentrations compared to other studies (1 µg/mL vs. 0.5 µg/mL [ 103 , 106 ] vs. 0.1 µg/mL [ 104 , 105 ]. Furthermore, in these studies, LPS-stimulated RAW264.7 cells were exposed to concentrations of SP600125 of 10 µM [ 103 , 106 ] and 20 µM [ 104 ]. Since data from our initial screening with SH-SY5Y ( Figure 2 A) indicated increased cytotoxicity of SP60125 at 10 µM, we cannot perform a direct comparison.…”

“…The major contribution of JNK to neuroinflammation is via its transcription factor, AP-1, which regulates proinflammatory genes such as COX2 , NOS2 , TNF- α, CCL2 , and VCAM-1 [ 100 ], and evidence suggests that ROS production induced by TNF-α is JNK-dependent [ 101 , 102 ]. In this case, we identified that FMU200 decreased TNF-α release in RAW264.7 cells after a 3 h treatment, but there was a smaller reduction in TNF-α after 24 h. In general, authors report a decrease in proinflammatory cytokines along with an increase in anti-inflammatory cytokines in LPS-induced RAW264.7 cells treated with SP600125 [ 103 , 104 , 105 , 106 ]. The cytotoxicity of different concentrations of LPS was evaluated in RAW264.7 cells by Tong et al According to their results, LPS at a maximum concentration of 1.25 µg/mL was not cytotoxic, (which provides support for the LPS concentration we used) and cytokine release (TNF-α and IL-6) was dose-dependent to LPS concentration.…”

Tropomodulin1 Expression Increases Upon Maturation in Dendritic Cells and Promotes Their Maturation and Immune Functions

“…The TRIF/IRF3 pathway, activated when TLR4 is endocytosed into the endosomal compartments, promotes the expression of anti-inflammatory cytokines ( 9 , 60 , 61 ). The induction of IRF3 does not occur from plasma membrane-located TLR4 ( 62 ).…”

The Anti-Inflammatory Properties of Phytochemicals and Their Effects on Epigenetic Mechanisms Involved in TLR4/NF-κB-Mediated Inflammation

“…It inhibits TLR4 and MyD88 expression in activated RAW 264.7 macrophages (142, 143) (Table 1 and Figure 1). Going downstream, RES inhibits NF-kB, MAPK, IRF-3 and AP-1 transcription factors, as well as, iNOS, COX-2, and 5-LOX enzymes (124,(143)(144)(145)(146)(147) (Table 1 and Figures 1 and 2). This, in turn, reduces NF-kB-induced proinflammatory cytokines, including TNF-a, IL-6, and IL-1b, and the free radicals, NO and ROS, and LTs and PGs levels (124,132,140,142,147,148,301) (Table 1 and Figure 2).…”