Anti-Inflammatory Activity of Glabralactone, a Coumarin Compound from Angelica sinensis, via Suppression of TRIF-Dependent IRF-3 Signaling and NF-κB Pathways.

The dried root of Angelica sinensis (A. sinensis) has been widely used in Chinese traditional medicine for various diseases such as inflammation, osteoarthritis, infections, mild anemia, fatigue, and high blood pressure. Searching for the secondary metabolites of A. sinensis has been mainly conducted. However, the bioactivity of coumarins in the plant remains unexplored. Therefore, this study was designed to evaluate the anti-inflammatory activity of glabralactone, a coumarin compound from A. sinensis, using in vitro and in vivo models, and to elucidate the underlying molecular mechanisms of action. Glabralactone effectively inhibited nitric oxide production in lipopolysaccharide- (LPS-) stimulated RAW264.7 macrophage cells. The downregulation of LPS-induced mRNA and protein expression of iNOS, TNF-α, IL-1ß, and miR-155 was found by glabralactone. The activation of NF-κB and TRIF-dependent IRF-3 pathway was also effectively suppressed by glabralactone in LPS-stimulated macrophages. Glabralactone (5 and 10 mg/kg) exhibited an in vivo anti-inflammatory activity with the reduction of paw edema volume in carrageenan-induced rat model, and the expressions of iNOS and IL-1ß proteins were suppressed by glabralactone in the paw soft tissues of the animal model. Taken together, glabralactone exhibited an anti-inflammatory activity in in vitro and in vivo models. These findings reveal that glabralactone might be one of the potential components for the anti-inflammatory activity of A. sinensis and may be prioritized in the development of a chemotherapeutic agent for the treatment of inflammatory diseases.

Caragana rosea Turcz Methanol Extract Inhibits Lipopolysaccharide-Induced Inflammatory Responses by Suppressing the TLR4/NF-κB/IRF3 Signaling Pathways.

Caragana rosea Turcz, which belongs to the Leguminosae family, is a small shrub found in Northern and Eastern China that is known to possess anti-inflammatory properties and is used to treat fever, asthma, and cough. However, the underlying molecular mechanisms of its anti-inflammatory effects are unknown. Therefore, we used lipopolysaccharide (LPS) in RAW264.7 macrophages to investigate the molecular mechanisms that underlie the anti-inflammatory activities of a methanol extract of Caragana rosea (Cr-ME). We showed that Cr-ME reduced the production of nitric oxide (NO) and mRNA levels of iNOS, TNF-α, and IL-6 in a concentration-dependent manner. We also found that Cr-ME blocked MyD88- and TBK1-induced NF-κB and IRF3 promoter activity, suggesting that it affects multiple targets. Moreover, Cr-ME reduced the phosphorylation levels of IκBα, IKKα/ß and IRF3 in a time-dependent manner and regulated the upstream NF-κB proteins Syk and Src, and the IRF3 protein TBK1. Upon overexpression of Src and TBK1, Cr-ME stimulation attenuated the phosphorylation of the NF-κB subunits p50 and p65 and IRF3 signaling. Together, our results suggest that the anti-inflammatory activity of Cr-ME occurs by inhibiting the NF-κB and IRF3 signaling pathways.

Dingchuan tang essential oil inhibits the production of inflammatory mediators via suppressing the IRAK/NF-κB, IRAK/AP-1, and TBK1/IRF3 pathways in lipopolysaccharide-stimulated RAW264.7 cells.

BACKGROUND: Dingchuan tang (asthma-relieving decoction), a formula of nine herbs, has been used for treating respiratory inflammatory diseases for >400 years in the People's Republic of China. However, the mechanisms underlying the anti-inflammatory action of dingchuan tang is not fully understood. This study aims to investigate the effects of Dingchuan tang essential oil (DCEO) on inflammatory mediators and the underlying mechanism of action. MATERIALS AND METHODS: DCEO was extracted by steam distillation. Lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were used as the cell model. Production of nitric oxide (NO) was determined by the Griess test. Protein secretion and mRNA levels of inflammatory mediators were measured by the enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. Protein levels were examined by Western blot. Nuclear localization of nuclear factor-kappa B (NF-κB) was detected using immunofluorescence analyses. RESULTS: DCEO significantly reduced LPS-triggered production of NO and prostaglandin E2 (PGE2) and decreased protein and mRNA levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). LPS induced upregulation of protein and mRNA levels of cytokines (interleukin-1ß [IL-1ß], interleukin-6 [IL-6], tumor necrosis factor-α [TNF-α]), and chemokines (monocyte chemoattractant protein-1 [MCP-1], chemokine [C-C motif] ligand 5 [CCL-5], and macrophage inflammatory protein [MIP]-1α) were suppressed by DCEO treatment. Phosphorylation and nuclear protein levels of transcription factors (activator protein-1 [AP-1], NF-κB, interferon regulatory factor 3 [IRF3]) were decreased by DCEO. Protein levels of phosphorylated IκB-α, IκB kinase α/ß (IKKα/ß), phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), TGF ß-activated kinase 1 (TAK1), TANK-binding kinase 1 (TBK1), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (p38), and c-Jun N-terminal kinase (JNK) were lowered by DCEO. Moreover, degradation of interleukin-1 receptor-associated kinase 1 (IRAK1) and IRAK4 induced by LPS was inhibited by DCEO treatment. CONCLUSION: Suppression of the interleukin-1 receptor-associated kinase (IRAK)/NF-κB, IRAK/AP-1 and TBK1/IRF3 pathways was associated with the inhibitory effects of DCEO on inflammatory mediators in LPS-stimulated RAW264.7 macrophages. This study provides a pharmacological justification for the use of dingchuan tang in managing inflammatory disorders.

A High Content Screen in Macrophages Identifies Small Molecule Modulators of STING-IRF3 and NFkB Signaling.

We screened a library of bioactive small molecules for activators and inhibitors of innate immune signaling through IRF3 and NFkB pathways with the goals of advancing pathway understanding and discovering probes for immunology research. We used high content screening to measure the translocation from the cytoplasm to nucleus of IRF3 and NFkB in primary human macrophages; these transcription factors play a critical role in the activation of STING and other pro-inflammatory pathways. Our pathway activator screen yielded a diverse set of hits that promoted nuclear translocation of IRF3 and/or NFkB, but the majority of these compounds did not cause activation of downstream pathways. Screening for antagonists of the STING pathway yielded multiple kinase inhibitors, some of which inhibit kinases not previously known to regulate the activity of this pathway. Structure-activity relationships (SARs) and subsequent chemical proteomics experiments suggested that MAPKAPK5 (PRAK) is a kinase that regulates IRF3 translocation in human macrophages. Our work establishes a high content screening approach for measuring pro-inflammatory pathways in human macrophages and identifies novel ways to inhibit such pathways; among the targets of the screen are several molecules that may merit further development as anti-inflammatory drugs.

In Vitro and In Vivo Anti-Allergic and Anti-Inflammatory Effects of eBV, a Newly Developed Derivative of Bee Venom, through Modulation of IRF3 Signaling Pathway in a Carrageenan-Induced Edema Model.

BACKGROUND: Bee venom (BV), a type of toxin extracted from honeybees (Apis mellifera), has been empirically and widely used to treat inflammatory diseases throughout Asia. Essential BV (eBV) was developed by removing phospholipase A2 (PLA2) and histamine to lower occurrence of allergic reaction. This study investigated the anti-allergic and anti-inflammatory activities of eBV in vitro and in vivo and its underlying mechanism of action. METHODS: The anti-inflammatory potential of eBV was assessed in vivo using a carrageenan-induced paw edema model. To further investigate the mechanism by which eBV exerts anti-allergic and anti-inflammatory effects, compound 48/80-stimulated RBL-2H3 cells and lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophage cells were studied in vitro. RESULTS: Release of ß-hexosaminidase and histamine was increased by eBV in a dose-dependent manner, but these levels were lower in eBV compared to original BV at the same concentration. In addition, eBV suppressed compound 48/80-induced expression of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) in RBL-2H3 cells. eBV was also shown to suppress nitric oxide (NO) production by down-regulating mRNA expression and subsequent protein expression of inflammatory mediators in LPS-induced RAW 264.7 cells. Phosphorylation of activators and signal transducers of transcription 1/interferon regulatory factor 3 (STAT1/IRF3) was attenuated by eBV treatment. eBV significantly inhibited carrageenan-induced acute edema in vivo. Serum levels of prostaglandin E2 (PGE2), TNF-α, and IL-1ß were also down-regulated by eBV. CONCLUSIONS: These results demonstrate that eBV inhibits allergic and inflammatory response by reducing inflammatory mediator production via regulation of the STAT1/IRF3 signaling pathway, suggesting that eBV is a feasible candidate for regulation of allergic-inflammatory response in complementary and alternative medicine.

A herbal formula comprising Rosae Multiflorae Fructus and Lonicerae Japonicae Flos inhibits the production of inflammatory mediators and the IRAK-1/TAK1 and TBK1/IRF3 pathways in RAW 264.7 and THP-1 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: As documented in the Chinese Materia Medica Grand Dictionary (), a herbal formula (RL) consisting of Rosae Multiflorae Fructus (multiflora rose hips) and Lonicerae Japonicae Flos (Japanese honeysuckle flowers) has traditionally been used in treating inflammatory disorders. RL was previously reported to inhibit the expression of various inflammatory mediators regulated by NF-κB and MAPKs that are components of the TLR4 signalling pathways. AIM OF THE STUDY: This study aims to provide further justification for clinical application of RL in treating inflammatory disorders by further delineating the involvement of the TLR4 signalling cascades in the effects of RL on inflammatory mediators. MATERIALS AND METHODS: RL consisting of Rosae Multiflorae Fructus and Lonicerae Japonicae Flos (in 5:3 ratio) was extracted using absolute ethanol. We investigated the effect of RL on the production of cytokines and chemokines that are regulated by three key transcription factors of the TLR4 signalling pathways AP-1, NF-κB and IRF3 in LPS-stimulated RAW264.7 cells using the multiplex biometric immunoassay. Phosphorylation of AP-1, NF-κB, IRF3, IκB-α, IKKα/ß, Akt, TAK1, TBK1, IRAK-1 and IRAK-4 were examined in LPS-stimulated RAW264.7 cells and THP-1 cells using Western blotting. Nuclear localizations of AP-1, NF-κB and IRF3 were also examined using Western blotting. RESULTS: RL reduced the secretion of various pro-inflammatory cytokines and chemokines regulated by transcription factors AP-1, NF-κB and IRF3. Phosphorylation and nuclear protein levels of these transcription factors were decreased by RL treatment. Moreover, RL inhibited the activation/phosphorylation of IκB-α, IKKα/ß, TAK1, TBK1 and IRAK-1. CONCLUSIONS: Suppression of the IRAK-1/TAK1 and TBK1/IRF3 signalling pathways was associated with the effect of RL on inflammatory mediators in LPS-stimulated RAW264.7 and THP-1 cells. This provides further pharmacological basis for the clinical application of RL in the treatment of inflammatory disorders.

Small molecule inhibits activity of scavenger receptor A: Lead identification and preliminary studies.

Scavenger receptor A (SRA) has been implicated in the processes of tumor invasion and acts as an immunosuppressor during therapeutic cancer vaccination. Pharmacological inhibition of SRA function thus holds a great potential to improve treatment outcome of cancer therapy. Macromolecular natural product sennoside B was recently shown to block SRA function. Here we report the identification and characterization of a small molecule SRA inhibitor rhein. Rhein, a deconstructed analog of sennoside B, reversed the suppressive activity of SRA in dendritic cell-primed T cell activation, indicated by transcription activation of il2 gene and production of IL-2. Rhein also inhibited SRA ligand polyinosinic:polycytidylic acid (poly(I:C)) induced activation of transcriptional factors, including interferon regulatory factor 3 (IRF3) and signal transducer and activator of transcription 1 (STAT1). Additionally, this newly identified lead compound was docked into the homology models of the SRA cysteine rich domain to gain insights into its interaction with the receptor. It was then found that rhein can favorably interact with SRA cysteine rich domain. Collectively, rhein, being the first identified small molecule inhibitors for SRA, warrants further structure-activity relationship studies, which may lead to development of novel pharmacological intervention for cancer therapy.

Anti-inflammatory activity of a water extract of Acorus calamus L. leaves on keratinocyte HaCaT cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Acorus calamus L., sweet flag, is a well-known medicinal plant that grows worldwide wildly along swamps, rivers, and lakes. AIM OF THE STUDY: The aim of this study was to evaluate the anti-inflammatory activity of Acorus calamus leaf (ACL) extract and to explore its mechanism of action on human keratinocyte HaCaT cells. MATERIALS AND METHODS: HaCaT cells treated with polyinosinic:polycytidylic acid (polyI:C) and peptidoglycan (PGN) induced the inflammatory reactions. The anti-inflammatory activities of ACL were investigated using RT-PCR, ELISA assay, immunoblotting, and immunofluorescence staining. RESULTS: HaCaT cells induced the pro-inflammatory cytokines, interleukin-8 (IL-8) and/or interleukin-6 (IL-6) expressions after treatment with polyI:C or PGN. ACL inhibited the expression of IL-8 and IL-6 RNA and protein levels, and attenuated the activation of NF-kappaB and IRF3 after polyI:C treatment. ACL also inhibited expression of IL-8 and activation of NF-kappaB following PGN induction. CONCLUSIONS: These results suggest that ACL inhibits the production of pro-inflammatory cytokines through multiple mechanisms and may be a novel and effective anti-inflammatory agent for the treatment of skin diseases.

Selenium suppresses the activation of transcription factor NF-kappa B and IRF3 induced by TLR3 or TLR4 agonists.

Toll-like receptors (TLRs) play an important role in recognition of microbial components and induce innate immune responses by recognizing invading microbial pathogens leading to the activation of the adaptive immune responses. The microbial components trigger the activation of two downstream signaling pathways of TLRs; MyD88- and TRIF-dependent pathways leading to the expression of pro-inflammatory cytokines and type I interferons (IFNs). The MyD88- and TRIF-dependent pathways lead to the activation of NF-kappa B and IRF3 through the activation of IKK-beta and TBK1, respectively. Selenium is an essential trace element nutrient possessing anticarcinogenic properties. Here, we attempted to identify the molecular targets of selenium in TLR signaling pathways. Selenium inhibited NF-kappaB activation induced by poly[I:C] (TLR3 agonist), LPS (TLR4 agonist) or overexpression of MyD88 or IKK-beta which is the key kinase of MyD88-dependent signaling pathway. Selenium inhibited IRF3 activation induced by poly[I:C], LPS or the overexpression of TRIF or TBK1. Selenium also suppressed the expression of COX-2 and iNOS and the endogenous IFN beta mRNA induced by poly[I:C] or LPS. Therefore, our results suggest that selenium can modulate both MyD88- and TRIF-dependent signaling pathways of TLRs leading to decreased inflammatory gene expression.