TLR4-mediated NF-κB Signaling Pathways Research Articles

Ugonin M, a Helminthostachys zeylanica Constituent, Prevents LPS-Induced Acute Lung Injury through TLR4-Mediated MAPK and NF-κB Signaling Pathways.

Helminthostachys zeylanica (L.) Hook. is plant that has been used in traditional Chinese medicine for centuries for the treatment of inflammation, fever, pneumonia, and various disorders. The aims of the present study are to figure out the possible effectiveness of the component Ugonin M, a unique flavonoid isolated from H. zeylanica, and to elucidate the mechanism(s) by which it works in the LPS-induced ALI model. In this study, Ugonin M not only inhibited the production of pro-inflammatory mediators such as NO, TNF-α, IL-1β, and IL-6, as well as infiltrated cellular counts and protein content in the bronchoalveolar lavage fluid (BALF) of lipopolysaccharides (LPS)-induced acute lung injury (ALI) mice, but also ameliorated the severity of pulmonary edemas through the score of a histological examination and the ratio of wet to dry weight of lung. Moreover, Ugonin M was observed to significantly suppress LPS-stimulated protein levels of iNOS and COX-2. In addition, we found that Ugonin M not only obviously suppressed NF-κB and MAPK activation via the degradation of NF-κB and IκB-α as well as ERK and p38MAPK active phosphorylation but also inhibited the protein expression level of TLR4. Further, Ugonin M treatment also suppressed the protein levels of MPO and enhanced the protein expressions of HO-1 and antioxidant enzymes (SOD, GPx, and CAT) in lung tissue of LPS-induced ALI mice. It is anticipated that through our findings, there is strong evidence that Ugonin M may exert a potential effect against LPS-induced ALI mice. Hence, Ugonin M could be one of the major effective components of H. zeylanica in the treatment of inflammatory disorders.

Calycosin Suppresses Epithelial Derived Initiative Key Factors and Maintains Epithelial Barrier in Allergic Inflammation via TLR4 Mediated NF-κB Pathway

Background/Aims: Calycosin is a bioactive component of Astragali Radix, a Chinese herb for treating allergy. We have previously demonstrated that calycosin effectively inhibited allergic inflammation efficiently. The aim of this study was to explore the mechanism of calycosin on epithelial cells in allergic inflammation. Methods: An initial stage of atopic dermatitis (AD) model in which mice were just sensitized with FITC, was established in vivo and immortalized human keratinocytes (HaCaT cells) were utilized in vitro. Initiative key cytokines, TSLP and IL-33, were measured by ELISA, qPCR, immunofluorescence and Western blot. The junctions in epithelial cells were observed by electron microscopy and tight junctions (TJs) (Occludin and ZO-1) were assessed by Western blot and immunofluorescence. TLR4, MyD88, TAK1, TIRAP and NF-κB were measured by qPCR or Western blot. Results: The results showed that TSLP and IL-33 were inhibited significantly by calycosin in the initial stage of AD model. Simultaneously, calycosin attenuated the separated gap among the epithelial cells and increased the expression of TJs. TSLP/IL-33 and TJs were similarly affected in LPS-stimulated HaCaT cells in vitro. Meanwhile, calycosin not only inhibited the expressions of TLR4, MyD88, TAK1 and TIRAP, but also reduced NF-κB activation in vitro and in vivo. An NF-κB inhibitor enhanced the expressions of TJs and reduced that of TSLP/IL-33 in LPS-stimulated HaCaT cells. Conclusion: These results indicated that calycosin reduced the secretion of TSLP/IL-33 and attenuated the disruption of epithelial TJs by inhibiting TLR4 mediated NF-κB signaling pathway. These findings help to understand the beneficial effects of calycosin on AD, and to develop effective preventive or therapeutic strategies to combat this disease and other epithelial barrier deletion-mediated allergic diseases.

Caffeic acid phenethyl ester attenuates lipopolysaccharide-stimulated proinflammatory responses in human gingival fibroblasts via NF-κB and PI3K/Akt signaling pathway

Periodontal diseases often begin with chronic gingival inflammation, which causes the destruction of periodontal tissues. Inflammatory immune responses from host cells to bacteria, such as Porphyromonas gingivalis (P. gingivalis), cause periodontal degradation. Human gingival fibroblasts (HGFs) are the major cells in periodontal soft tissues. When stimulated by lipopolysaccharide (LPS), HGFs could secrete several pro-inflammatory cytokines and chemokines, such as interleukins (ILs) IL-6, IL-8, inducible nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX-2). Caffeic acid phenethyl ester (CAPE) is the main active component of propolis, which is collected by honeybees from different plants and known for its anti-inflammatory effects. The anti-inflammatory effects of CAPE on the LPS-induced HGFs were demonstrated in this study. HGFs were pretreated with CAPE (10, 20, and 30µm) for 1h, followed by LPS stimulation (1μg/ml) for 24h. Enzyme-linked immunosorbent assay, Western blot analysis, and immunofluorescence staining were used to evaluate the production of IL-6, IL-8, iNOS, and COX-2, as well as the activation of TLR4-mediated NF-κB, PI3K/AKT, and MAPK signaling pathways. The results indicated that CAPE inhibits LPS-induced IL-6, IL-8, iNOS, and COX-2 production in a dose-dependent manner. Moreover, CAPE suppresses LPS-induced TLR4/MyD88 and nuclear factor kappa B (NF-κB) activation. In addition, phosphatidylinositol 3 kinase (PI3K) and protein kinase B (AKT) phosphorylation was inhibited by CAPE. These results demonstrated that CAPE could be effective for treating of periodontal diseases.

Oleoylethanolamide exerts anti-inflammatory effects on LPS-induced THP-1 cells by enhancing PPARα signaling and inhibiting the NF-κB and ERK1/2/AP-1/STAT3 pathways.

The present study aimed to examine the anti-inflammatory actions of oleoylethanolamide (OEA) in lipopolysaccharide (LPS)-induced THP-1 cells. The cells were stimulated with LPS (1 μg/ml) in the presence or absence of OEA (10, 20 and 40 μM). The pro-inflammatory cytokines were evaluated by qRT-PCR and ELISA. The THP-1 cells were transiently transfected with PPARα small-interfering RNA, and TLR4 activity was determined with a blocking test using anti-TLR4 antibody. Additionally, a special inhibitor was used to analyse the intracellular signaling pathway. OEA exerted a potent anti-inflammatory effect by reducing the production of pro-inflammatory cytokines and TLR4 expression, and by enhancing PPARα expression. The modulatory effects of OEA on LPS-induced inflammation depended on PPARα and TLR4. Importantly, OEA inhibited LPS-induced NF-κB activation, IκBα degradation, expression of AP-1, and the phosphorylation of ERK1/2 and STAT3. In summary, our results demonstrated that OEA exerts anti-inflammatory effects by enhancing PPARα signaling, inhibiting the TLR4-mediated NF-κB signaling pathway, and interfering with the ERK1/2-dependent signaling cascade (TLR4/ERK1/2/AP-1/STAT3), which suggests that OEA may be a therapeutic agent for inflammatory diseases.

Corrigendum] TLR4-mediated NF-κB signaling pathway mediates HMGB1-induced pancreatic injury in mice with severe acute pancreatitis.

Following the publication of the article, the authors noted that there were certain errors in Fig.5. In particular, the published Fig.5A-a contains an image of H&E-stained micrographs from wild-type mice after the administration of a low dose of rhHMGB1, and not after the administration of a high dose of rhHMGB1, as should be shown. In addition, the data in the published graph of Fig.5C-a is not correct and in Fig. 5C‑b, the significance marker is merged with the error bars and is not evident. [the original article was published in the International Journal of Molecular Medicine 37: 99-107, 2016; DOI: 10.3892/ijmm.2015.2410].

Protective effect of the essential oil of Zanthoxylum myriacanthum var. pubescens against dextran sulfate sodium-induced intestinal inflammation in mice

BackgroundZanthoxylum myriacanthum var. pubescens is an ethnic medicine for digestive disease known as Maqian. A previous report showed that the Maqian fruits essential oil (MQEO) exhibited an NO inhibitory effect on RAW 264.7 cells, but the effect on inflammatory disease in vivo remains unknown. PurposeTo investigate the anti-inflammatory effect of Z. myriacanthum var. pubescens as potential candidate for the treatment of intestinal inflammation. Study designEvaluation of anti-inflammatory effect of MQEO using dextran sulfate sodium (DSS)-induced intestinal inflammation in mice and exploration of the mechanisms with THP-1 cells. MethodsC57BL/6 mice were provided drinking water containing 3% DSS for 10 days followed by normal drinking water for 3 days. MQEO (35 and 70mg/kg) were given 5 days before experiments and continued for another 13 days. At the end of experiments, mice were euthanized and colonic tissue was collected to be analyzed by H&E staining, RT-PCR and immunohistochemistry for evaluating the damage of colons, the mRNA levels of IL-1β, IL-6, IL-12p35 and TNF-α, and the expressions of myeloperoxidase (MPO) and matrix metalloproteinase-9 (MMP-9). The LPS-stimulated THP-1 cell line was used for exploring the role of inflammatory markers using ELISA, western blot and flow cytometry methods. ResultsOral administration of MQEO (35 and 70mg/kg) markedly attenuated the symptoms of intestinal inflammation, including diarrhea, rectal bleeding, and loss of body weight. It also reduced the shortening of colon length and histopathological damage. The expressions of MPO and MMP-9 and the mRNA levels of pro-inflammatory cytokines (IL-1β, IL-6 and IL-12p35) in colonic tissue significantly decreased after MQEQ treatment. The activation of NF-κB p65 in colonic mucosa was also markedly suppressed. In addition, MQEO significantly suppressed LPS-stimulated production of TNF-α and IL-1β, effectively blocked phosphorylation of IKK and IκB, and dose-dependently reduced LPS-stimulated expression of TLR4 in THP-1 cells at concentrations ranging from 0.01‰ to 0.05‰ (v/v). ConclusionMQEO exhibited protective effect against DSS-induced intestinal inflammation and the anti-inflammatory activity may be associated with TLR4 mediated NF-κB signaling pathway, suggesting it might be used as an anti-inflammatory agent.

Kegan Liyan oral liquid ameliorates lipopolysaccharide-induced acute lung injury through inhibition of TLR4-mediated NF-κB signaling pathway and MMP-9 expression

Ethnopharmacological relevanceKegan Liyan oral liquid (KGLY), a Chinese prescription modified from classic formulas Yin-Qiao-San (from TCM classic Wenbing Tiaobian) and Shen-Jie-San (first mentioned in Shanghan Wenyi Tiaobian), has been reported to exert heat-clearing and detoxifying effects and used extensively for the treatment of severe pulmonary diseases in clinics including influenza, cough and pneumonia. Aim of this studyThe purpose of this study was to investigate the protective effect of KGLY on lipopolysaccharide (LPS) induced acute lung injury (ALI) in mice and to illuminate the underlying mechanisms. Materials and methodsMice were orally administrated with KGLY (50, 100 and 150mg/kg) before intratracheal instillation of LPS. 24h post LPS challenge, lung tissues and the bronchoalveolar lavage fluid (BALF) were collected for lung wet/dry (W/D) weight ratio, histopathological examinations and biochemical analyses. The cell counts, protein concentration, interleukin-1β (IL-1β), interleukin-6 (IL-6), necrosis factor-α (TNF-α), macrophage inflammatory protein-2 (MIP-2) in BALF, superoxide dismutase (SOD), glutathione (GSH), myeloperoxidase (MPO) and malondialdehyde (MDA) levels were detected. Meanwhile, the activation of toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), as well as matrix metalloproteinases 9 (MMP-9) were determined by western blot assay. ResultsKGLY significantly prolonged mice survival time and ameliorated LPS-induced edema, thickening of alveolar septa and inflammatory cell infiltration in a dose-dependent manner. Additionally, KGLY markedly attenuated LPS-induced acute pulmonary inflammation via decreasing the expressions of cytokines and chemokines (IL-1β, IL-6, TNF-α, and MIP-2), enhanced the activities of anti-oxidative indicators (SOD and GSH), suppressed the levels of MPO and MDA, and down-regulated the expressions of TLR4, NF-κB and MMP9. ConclusionsThe results suggested that the relieving effect of KGLY against LPS-induced ALI might be partially due to suppression of oxidative stress and inflammatory response, inhibition of TLR4-mediated NF-κB activation, and down-regulation of MMP9 expression, indicating it may be a potential therapeutic agent for ALI.

The anti-inflammatory effect of TR6 on LPS-induced mastitis in mice

[TRIAP]-derived decoy peptides have anti-inflammatory properties. In this study, we synthesized a TRIAP-derived decoy peptide (TR6) containing, the N-terminal portion of the third helical region of the [TIRAP] TIR domain (sequence “N”-RQIKIWFQNRRMKWK and -KPGFLRDPWCKYQML-“C”). We evaluated the effects of TR6 on lipopolysaccharide-induced mastitis in mice. In vivo, the mastitis model was induced by LPS administration for 24h, and TR6 treatment was initiated 1h before or after induction of LPS. In vitro, primary mouse mammary epithelial cells and neutrophils were used to investigate the effects of TR6 on LPS-induced inflammatory responses. The results showed that TR6 significantly inhibited mammary gland hisopathologic changes, MPO activity, and LPS-induced production of TNF-α, IL-1β and IL-6. In vitro, TR6 significantly inhibited LPS-induced TNF-α and IL-6 production and phosphorylation of NF-κB and MAPKs. In conclusion, this study demonstrated that the anti-inflammatory effect of TR6 against LPS-induced mastitis may be due to its ability to inhibit TLR4-mediated NF-κB and MAPK signaling pathways. TR6 may be a promising therapeutic reagent for mastitis treatment.

TLR4-mediated NF-κB signaling pathway mediates HMGB1-induced pancreatic injury in mice with severe acute pancreatitis.

Severe acute pancreatitis (SAP) is an extremely dangerous acute abdominal disorder which causes multiple complications and has a high mortality rate. Previous research has suggested that high-mobility group box 1 (HMGB1) plays an important role in the pathogenesis of SAP; however, the mechanisms underlying this strong correlation remain unclear. In this study, to further investigate whether HMGB1 acts as a stimulating factor, and whether Toll-like receptor 4 (TLR4) acts as its major mediator in the development of pancreatic injury during SAP, recombinant human HMGB1 (rhHMGB1) and TLR4-deficient mice were used. We found that HMGB1 and TLR4 were highly expressed, and nuclear factor-κB (NF-κB) was activated in our mouse model of SAP. We noted that the rhHMGB1 pancreas-targeted injection activated the TLR4-mediated NF-κB signaling pathway and induced pancreatic injury in wild-type mice. In TLR4-deficient mice, the rhHMGB1-induced activation of NF-κB and pathological changes in the pancreas were less evident than in wild-type mice. Therefore, this study provides evidence that HMGB1 promotes the pathogenesis of pancreatitis, and its downstream TLR4-mediated NF-κB signaling pathway is a potential important mediator in the development of this form of pancreatic injury.

Fisetin Alleviates Lipopolysaccharide-Induced Acute Lung Injury via TLR4-Mediated NF-κB Signaling Pathway in Rats.

Acute lung injury (ALI), a common component of systemic inflammatory disease, is a life-threatening condition without many effective treatments. Fisetin, a natural flavonoid from fruits and vegetables, was reported to have wide pharmacological properties such as anti-inflammatory, antioxidant, and anticancer activities. The aim of this study was to detect the effects of fisetin on lipopolysaccharide (LPS)-induced acute lung injury and investigate the potential mechanism. Fisetin was injected (1, 2, and 4mg/kg, i.v.) 30min before LPS administration (5mg/kg, i.v.). Our results showed that fisetin effectively reduced the inflammatory cytokine release and total protein in bronchoalveolar lavage fluids (BALF), decreased the lung wet/dry ratios, and obviously improved the pulmonary histology in LPS-induced ALI. Furthermore, fisetin inhibited LPS-induced increases of neutrophils and macrophage infiltration and attenuated MPO activity in lung tissues. Additionally, fisetin could significantly inhibit the Toll-like receptor 4 (TLR4) expression and the activation of NF-κB in lung tissues. Our data indicates that fisetin has a protective effect against LPS-induced ALI via suppression of TLR4-mediated NF-κB signaling pathways, and fisetin may be a promising candidate for LPS-induced ALI treatment.

Protocatechuic Acid Inhibits Inflammatory Responses in LPS-Stimulated BV2 Microglia via NF-κB and MAPKs Signaling Pathways.

Protocatechuic acid (PA), a major metabolite of anthocyanins, has been reported to possess antioxidant and anti-inflammatory activities. However, the effects of PA on LPS-induced inflammatory responses in microglia have not been reported. The aim of this study was to investigate the anti-inflammatory effects and molecular mechanisms of PA on LPS-stimulated BV2 microglia. The production of inflammatory mediators TNF-α, IL-6, IL-1β, and PGE2 were detected by ELISA. TLR4, NF-κB and MAPKs activation were detected by western blotting. Our results demonstrated that PA dose-dependently inhibited LPS-induced TNF-α, IL-6, IL-1β, and PGE2 production. In addition, PA suppressed LPS-induced TLR4 expression, NF-κB and MAPKs activation, which resulted in the inhibition of inflammatory mediators. In conclusion, these results suggested that PA exhibited anti-inflammatory effects on LPS-stimulated BV2 microglia and the mechanisms were involved in the inhibition of TLR4-mediated NF-κB and MAPKs signaling pathways.

S100A9-induced release of interleukin (IL)-6 and IL-8 through toll-like receptor 4 (TLR4) in human periodontal ligament cells.

S100A8, S100A9, and calprotectin (the S100A8/S100A9 complex) are calcium-binding proteins that promote extracellular pro-inflammatory functions and may play an important role in periodontal disease. Both toll-like receptor 4 (TLR4) and the receptor for advanced glycation end-products (RAGE) are thought to be important receptors for S100A8, S100A9, and calprotectin, but the specific pathways in periodontal ligament (PDL) cells are not yet clear. Our study was designed to identify the specific receptors for S100A9 in human PDL cells. Additionally, we investigated the specific pathways that activate the secretion of pro-inflammatory cytokines interleukins (IL)-6 and IL-8 in PDL cells. The role of nuclear factor (NF)-κB, mitogen-activated protein kinase (MAPK) and reactive oxygen species (ROS) in S100A9-induced pro-inflammatory cytokines were investigated through western blot analysis, dichlorodihydrofluorescein diacetate (H2DCFDA) probe and the application of specific pathway inhibitors. Our results suggest that the S100A9-induced release of IL-6 and IL-8 from human PDL cells is dependent on TLR4, but not RAGE. We provide evidence that S100A9 promotes the secretion of IL-6 and IL-8 through different pathways. Specifically, S100A9 up-regulates the secretion of IL-6 from human PDL cells through NF-κB and p38 pathways and up-regulates the release of IL-8 from human PDL cells through the NF-κB, extracellular-regulated kinase (ERK) 1/2, c-Jun amino-terminal kinase (JNK) 1/2, and p38 signaling pathways. In addition, the release of both cytokines depends on ROS production. The release of both cytokines depends on ROS production. These results suggest that S100A9 promotes pro-inflammatory responses in PDL cells through the TLR4-mediated NF-κB and MAPK signaling pathways.

Parthenolide inhibits LPS-induced inflammatory cytokines through the toll-like receptor 4 signal pathway in THP-1 cells.

Parthenolide (PTL) shows potent anti-inflammatory and anti-cancer activities. In the present study, the molecular mechanisms of PTL's activities were explored in lipopolysaccharide (LPS)-induced human leukemia monocytic THP-1 cells and human primary monocytes. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt (MTS) assay was used to analyze the effect of PTL on THP-1 cell viability. Enzyme-linked immunosorbent assay was used to determine the effect of PTL on LPS-induced inflammatory cytokine secretion. Flow cytometry and quantitative real-time polymerase chain reaction were used to assess the effect of PTL on LPS-induced toll-like receptor 4 (TLR4) expression. Phosphorylation levels of signaling molecules were determined by western blot analysis. Results showed that PTL <12.5 μM did not significantly affect THP-1 cells viability. LPS treatment led to a marked up-regulation of interleukin (IL)-6, IL-1β, IL-8, IL-12p40, tumor necrosis factor-α, IL-18, and NO in THP-1 cells. However, PTL inhibited the expression of these cytokines in a dose-dependent manner, with IC50 values of 1.091-2.620 μM. PTL blocked TLR4 expression with an IC50 value of 1.373 μM as determined by the flow cytometry analysis, and this blocking effect was verified at both protein and mRNA levels. Up-regulation of phosphorylation levels of extracellular signal-regulated kinase 1/2, Jun N-terminal kinase, p38, nuclear factor κB (NF-κB) p65, and IκBα and up-regulation of expressions of other molecules (inducible nitric oxide synthase, TLR4, and TNF receptor-associated factor 6) induced by LPS were abolished by PTL in a dose-dependent manner. The anti-inflammatory mechanisms of PTL operate partly through the TLR4-mediated mitogen-activated protein kinase and NF-κB signaling pathways. Therefore, TLR4 may be a new target for anti-inflammation therapies.

Acanthoic acid inhibits LPS-induced inflammatory response in human gingival fibroblasts.

Periodontitis is a chronic disease that affects the gums and destroys connective tissue. Acanthoic acid (AA), a diterpene in Acanthopanax koreanum, has been reported to have anti-inflammatory activities. The aim of this study was to investigate the anti-inflammatory effects of AA on lipopolysaccharide (LPS)-induced inflammatory response in human gingival fibroblasts (HGFs). HGFs were treated with Porphyromonas gingivalis LPS in the presence or absence of AA. The production of inflammatory cytokines IL-8 and IL-6 were measured by ELISA. The expression of NF-κB and TLR4 were detected by Western blotting. The results showed that AA inhibited LPS-induced IL-8 and IL-6 production in a dose-dependent manner. In addition, AA inhibited LPS-induced TLR4 expression and NF-κB activation. In conclusion, AA inhibits LPS-induced inflammatory response in HGFs through inhibition TLR4-mediated NF-κB signaling pathway.

Protective effects of scoparone against lipopolysaccharide-induced acute lung injury.

The purpose of this study was to investigate the protective effects and molecular mechanisms of scoparone on lipopolysaccharide (LPS)-induced acute lung injury in mice. Mice model of acute lung injury (ALI), induced by intranasal instillation of LPS, was used to investigate the protective effects of scoparone in vivo. The alveolar macrophages were used to investigate the molecular mechanisms of scoparone in vitro. The results showed that scoparone treatment remarkably attenuated LPS-induced pulmonary edema, histological severities, myeloperoxidase activity, and TNF-α, IL-6 and IL-1β production in vivo. We also found that scoparone inhibited LPS-induced TLR4 expression, NF-κB activation, TNF-α, IL-6 and IL-1β production in alveolar macrophages in vitro. In conclusion, our results suggest that scoparone has a protective effect on LPS-induced ALI via suppression of TLR4-mediated NF-κB signaling pathways.

Protective effect of catalpol on lipopolysaccharide-induced acute lung injury in mice.

Catalpol, an iridiod glucoside isolated from Rehmannia glutinosa, has been reported to have anti-inflammatory properties. Although anti-inflammatory activity of catalpol already reported, its involvement in lung protection has not been reported. Thus, we investigated the role of catalpol on lipopolysaccharide (LPS)-induced acute lung injury in this study. Mice acute lung injury model was induced by intranasal instillation of LPS. Catalpol was administrated 1h prior to or after LPS exposure. The severity of pulmonary injury was evaluated 12h after LPS administration. The results showed that catalpol inhibited lung W/D ratio, myeloperoxidase activity of lung samples, the amounts of inflammatory cells and TNF-α, IL-6, IL-4 and IL-1β in BALF induced by LPS. The production of IL-10 in BALF was up-regulated by catalpol. In vitro, catalpol inhibited TNF-α, IL-6, IL-4 and IL-1β production and up-regulated IL-10 expression in LPS-stimulated alveolar macrophages. Moreover, western blot analysis showed that the activation of NF-κB and MAPK signaling pathways was inhibited by catalpol. Furthermore, catalpol was found to inhibit TLR4 expression induced by LPS. In conclusion, catalpol potently protected against LPS-induced ALI. The protective effect may attribute to the inhibition of TLR4-mediated NF-κB and MAPK signaling pathways.

Punicalagin ameliorates lipopolysaccharide-induced acute respiratory distress syndrome in mice.

Punicalagin, a bioactive ellagitannin isolated from pomegranate, has been reported to have anti-inflammatory property. In the present study, we analyzed the role of punicalagin against acute respiratory distress syndrome (ARDS) induced by lipopolysaccharide (LPS) in mice. Male BALB/c mice with ARDS, induced by intranasal instillation of LPS, were treated with punicalagin 1 h prior to LPS exposure. The effects of punicalagin on pro-inflammatory cytokines, myeloperoxidase activity, nuclear factor kappa B (NF-κB) activation, and the histopathological changes were evaluated. The results showed that punicalagin treatment attenuated LPS-induced lung edema, elevating TNF-α, IL-6, and IL-1β levels in the bronchoalveolar lavage fluid (BALF). Meanwhile, punicalagin significantly inhibited LPS-induced increases in the macrophage and neutrophil infiltration of lung tissues and myeloperoxidase activity. Furthermore, punicalagin inhibits Toll-like receptor 4 (TLR4) expression and NF-κB activation induced by LPS. In conclusion, this is the first study to demonstrate that punicalagin protects against LPS-induced ARDS in mice. The underlying mechanisms may include inhibition of TLR4-mediated NF-κB signaling pathways.

Inhibitory effects of astragalin on lipopolysaccharide-induced inflammatory response in mouse mammary epithelial cells

BackgroundTea brewed from the leaves of persimmon or Rosa agrestis have several medical functions including treating allergy, antiatopic dermatitis, and anti-inflammatory effects. The objective of this study was to investigate the molecular mechanisms of astragalin, a main flavonoid component isolated from these herbs, in modifying lipopolysaccharide (LPS)-induced signaling pathways in primary cultured mouse mammary epithelial cells (mMECs). Materials and methodsThe mMECs were treated with LPS in the absence or presence of different concentrations of astragalin. The expression of proinflammatory cytokines tumor necrosis factor α, and interleukin 6, as well as nitric oxide production were determined by enzyme-linked immunosorbent assay and Griess reaction, respectively. Cyclooxygenase-2, inducible nitric oxide synthase, toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB), inhibitor protein of NF-κB (IκBα), P38, extracellular signal-regulated kinase, and c-Jun N-terminal kinase were measured by Western blot. ResultsThe results showed that astragalin suppressed the expression of tumor necrosis factor α, interleukin 6, and nitric oxide in a dose-dependent manner in mMECs. Western blot results showed that the expression of inducible nitric oxide synthase and cyclooxygenase-2 was inhibited by astragalin. Besides, astragalin efficiently decreased LPS-induced TLR4 expression, NF-κB activation, IκBα degradation, and the phosphorylation of p38, extracellular signal-regulated kinase in BMECs. ConclusionsOur results indicated that astragalin exerts anti-inflammatory properties possibly via the inactivation of TLR4-mediated NF-κB and mitogen-activated protein kinases signaling pathways in LPS-stimulated mMECs. Thus, astragalin may be a potential therapeutic agent for bovine mastitis.

Wogonoside ameliorates lipopolysaccharide-induced acute lung injury in mice.

Wogonoside has been reported to have anti-inflammatory properties. In this study, we evaluated the effect of wogonoside on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Male BALB/c mice with ALI, induced by intranasal instillation of LPS, were treated with wogonoside 1h prior to LPS exposure. Mice treated with LPS alone showed significantly increased TNF-α, IL-6, and IL-1β levels in the bronchoalveolar lavage fluid (BALF). When pretreated with wogonoside, the TNF-α, IL-6, and IL-1β levels were significantly decreased. Meanwhile, wogonoside significantly inhibited LPS-induced increases in the macrophage and neutrophil infiltration of lung tissues and markedly attenuated myeloperoxidase activity. Furthermore, wogonoside inhibited the TLR4 expression and the phosphorylation of NF-κB p65, and IκB induced by LPS. In conclusion, our results indicate that wogonoside exhibits a protective effect on LPS-induced ALI via suppression of TLR4-mediated NF-κB signaling pathways.

Curcumin attenuates inflammatory responses by suppressing TLR4-mediated NF-κB signaling pathway in lipopolysaccharide-induced mastitis in mice

Curcumin, the main constituent of the spice turmeric, has been reported to have potent anti-inflammatory properties. However, the effect of curcumin on lipopolysaccharide (LPS)-induced mice mastitis has not been investigated. The aim of this study was to investigate whether curcumin could ameliorate the inflammation response in LPS-induced mice mastitis and to clarify the possible mechanism. The mouse model of mastitis was induced by injection of LPS through the duct of the mammary gland. Curcumin was applied 1h before and 12h after LPS treatment. The results showed that curcumin attenuated the infiltration of inflammatory cells, the activity of myeloperoxidase (MPO), and the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in a dose-dependent manner. Additionally, Western blotting results showed that curcumin inhibited the phosphorylation of IκB-α and NF-κB p65 and the expression of TLR4. These results indicated that curcumin has protective effect on mice mastitis and the anti-inflammatory mechanism of curcumin on LPS-induced mastitis in mice may be due to its ability to inhibit TLR4-mediated NF-κB signaling pathways. Curcumin may be a potential therapeutic agent against mastitis.