Search

Abstract: Aims: The purpose of this study was to evaluate the therapeutic potential of the helenalin in Toll-like receptor (TLR) signaling pathways. Main methods: RAW264.7 cells were transfected with a NF-κB, IFNβ PRDIII-I, or IP-10 luciferase plasmid and then luciferase enzyme activities were determined by luciferase assay. The expression of iNOS, COX-2, and IP-10 and phosphorylation of IRF3 were determined by Western blotting. The levels of IP-10 were determined with culture medium by using IP-10 ELISA kit. TBK1 kinase activity was determined by MBP assay kit. Key findings: Helenalin inhibited transcription factor NF-κB and IRF3 activation, which was induced by TLR agonists as well as its target genes, such as COX-2, iNOS, and IP-10. Helenalin attenuated ligand-independent activation of NF-κB induced by MyD88, IKKβ, and p65, and IRF3 induced by TRIF, TBK1, or IRF3. Furthermore, helenalin inhibited TBK1 kinase activity in vitro. Significance: TLRs are primary sensors that detect a wide variety of microbial components and play an important role in the induction of innate immune. To evaluate the therapeutic potential of helenalin, we examined its effect on signal transduction via the TLR signaling pathways. Our results suggest that beneficial effects of helenalin on chronic inflammatory diseases are mediated through modulation of TLR signaling pathways by targeting TBK1. [Copyright &y& Elsevier]

Nuclear factor-κB (NF-κB) is a transcription factor that mediates the inducible expression of a variety of genes involved in immune and inflammatory responses. NF-κB activation induces numerous proinflammatory gene products including cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). The divalent heavy metal mercury has been used for thousands of years. Although mercury is clearly toxic to most mammalian organ systems, especially the immune system, exposure has still increased in some areas of the world. However, the underlying toxic mechanism is not clearly identified. Here, we report biochemical evidence that mercury alone induces NF-κB activation, resulting in the induced expression of COX-2 and iNOS. The results suggest that mercury can induce inflammatory diseases by lowering host defense. [ABSTRACT FROM AUTHOR]

Abstract: A 3-dimensional alumina (Al203) implant consisting of a continuous porous structure was fabricated using a fibrous monolithic process and its biocompatibility was evaluated through in vitro procedures and in vivo angiogenesis. In vitro experiments were carried out using human osteoblast like cells, MG-63 and osteoclast-like cells, Raw-264.7. Cellular proliferation and growth behavior were examined on the specimen surfaces by SEM. Highly condensed, circular cells with three-dimensional network like growth pattern was observed inside the pore surfaces using MG-63 cells. In contrast, the osteoclast-like Raw 264.7 cells had a multi-layered pebblestone appearance with interconnections. Moreover, the crystalline-like nodules generated by osteoblasts cultured on an Al2O3 porous body were shown to have resulted from the in vitro mineralization of calcium-phosphate deposits. To investigate the in vivo angiogenesis, 3-dimensional Al2O3 porous bodies were implanted into the subcutaneous tissues of rats. The porous bodies were completely filled with fibroblasts at 4weeks and the formation of new blood vessels inside the porous body was observed at 6weeks. [Copyright &y& Elsevier]

Abstract: Toll-like receptors (TLRs) play important inductive roles in innate immune responses for host defense against invading microbial pathogens. Activation of TLR4 by lipopolysaccharide (LPS) induces dimerization of TLR4 and, subsequently, activation of downstream signaling pathways including nuclear factor-kappa B and interferon regulatory factor 3. TLR4 dimerization may be an early regulatory event in activating signaling pathways induced by LPS. Here, biochemical evidence is reported that isoliquiritigenin, one of the major ingredients derived from licorice root, inhibits LPS-induced TLR4 dimerization resulting in inhibition of nuclear factor-kappa B and interferon regulatory factor 3 activation, and cyclooxygenase-2 and inducible nitric oxide synthase expression. These results suggest that isoliquiritigenin modulates TLR-mediated signaling pathways at the receptor level. Furthermore, these results suggest that TLRs themselves may be important targets for the prevention of chronic inflammatory diseases. [Copyright &y& Elsevier]

Abstract: Toll-like receptors (TLRs) are vital in the induction of innate immune responses. The microbial components trigger the activation of the myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent downstream TLR signaling pathways. Guggulsterone, which has been used for centuries to treat many chronic diseases, inhibits the MyD88-dependent pathway by inhibiting the activity of inhibitor-κB kinase. However, it is not known whether guggulsterone inhibits the TRIF-dependent pathway. Presently, we sought to identify the molecular targets of guggulsterone in this pathway. Guggulsterone inhibited nuclear factor-κB and IRF3 activation induced by lipopolysaccharide or poly[I:C] and activation of IRF3 induced by the overexpression of TRIF, TBK1 or constitutively active IRF3. Guggulsterone also suppressed the lipopolysaccharide-induced phosphorylation of IRF3. These results suggest that guggulsterone can modulate both MyD88- and TRIF-dependent signaling pathways of TLRs leading to decreased inflammatory gene expression. [Copyright &y& Elsevier]

Abstract: 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-κB and IRF3 through the activation of IKK-β 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-κB activation induced by poly[I:C] (TLR3 agonist), LPS (TLR4 agonist) or overexpression of MyD88 or IKK-β 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 IFNβ 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. [Copyright &y& Elsevier]

Gremlin-1 (GREM1), one of the antagonists of bone morphogenetic proteins (BMPs), has recently been reported to be overexpressed in a variety of cancers including breast cancer. GREM1 is involved in tumor promotion, but little is known about its role in the glycolysis of cancer cells. In this study, we investigated the role of GREM1 in glycolysis of breast cancer cells and its underlying molecular mechanisms. We first observed that glucose uptake and lactate production were increased in GREM1-overexpressing breast cancer cells. GREM1 increased the expression of hexokinase-2 (HK2), which catalyzes the phosphorylation of glucose, the first step in glycolysis. In addition, GREM1 activated STAT3 transcription factor through the ROS-Akt signaling pathway. The ROS-Akt-STAT3 axis activated by GREM1 was involved in promoting glucose uptake by increasing the expression of HK2 in breast cancer cells. Therefore, our study suggested a new mechanism by which GREM1 is involved in breast cancer promotion by increasing glycolysis in breast cancer cells. • GREM1 promotes glycolysis in breast cancer cells. • GREM1 increases the expression of HK2, which catalyzes the phosphorylation of glucose, the first step in glycolysis. • GREM1 induces ROS production, leading to Akt and STAT3 activation. • The ROS-Akt-STAT3 axis contributes to the expression of HK2 induced by GREM1. [ABSTRACT FROM AUTHOR]

Abstract: Toll-like receptors (TLRs) play an important role by recognizing many pathogen-associated molecular patterns and inducing innate immunity. Dysregulated activation of TLR signaling pathways induces the activation of various transcription factors such as nuclear factor-κB, leading to the induction of pro-inflammatory gene products such as inducible nitric oxide synthase (iNOS). The present study investigated the effect of isobavachalcone (IBC), a natural chalcone component of Angelica keiskei, on inflammation by modulating iNOS expression induced by TLR agonists in murine macrophages. IBC suppressed iNOS expression induced by macrophage-activating lipopeptide 2-kDa, polyriboinosinic polyribocytidylic acid, or lipopolysaccharide. These results indicate the potential of IBC as a potent anti-inflammatory drug. [Copyright &y& Elsevier]

Toll-like receptors (TLRs) play an important role in induction of innate immune responses for host defense against invading microbial pathogens. Microbial component engagement of TLRs can trigger the activation of myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent downstream signaling pathways. Parthenolide, an active ingredient of feverfew ( Tanacetum parthenium), has been used for centuries to treat many chronic diseases. Parthenolide inhibits the MyD88-dependent pathway by inhibiting the activity of inhibitor-κB kinase. However, it is not known whether parthenolide inhibits the TRIF-dependent pathway. To evaluate the therapeutic potential of parthenolide, its effect on signal transduction via the TRIF-dependent pathway of TLRs induced by lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly [I:C]) was examined. Parthenolide inhibited nuclear factor-κB and interferon regulatory factor 3 activation induced by LPS or poly[I:C], and the LPS-induced phosphorylation of interferon regulatory factor 3 as well as interferon-inducible genes such as interferon inducible protein-10. These results suggest that parthenolide can modulate TRIF-dependent signaling pathways of TLRs, and may be the basis of effective therapeutics for chronic inflammatory diseases. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) play an important role in host defense by sensing invading microbial pathogens and initiating innate immune responses. The stimulation of TLRs by microbial components triggers the activation of myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent downstream signaling pathways. Isoliquiritigen in (ILG), an active ingredient of Licorice, has been used for centuries to treat many chronic diseases. ILG inhibits the MyD88-dependent pathway by inhibiting the activity of inhibitor-κB kinase. However, it is not known whether ILG inhibits the TRIF-dependent pathway. To evaluate the therapeutic potential of ILG, we examined its effect on signal transduction via the TRIF-dependent pathway of TLRs induced by several agonists. ILG inhibited nuclear factor-κB and interferon regulatory factor 3 activation induced by lipopolysaccharide or polyinosinic-polycytidylic acid. ILG inhibited the lipopolysaccharide-induced phosphorylation of interferon regulatory factor 3 as well as interferon-inducible genes such as interferon inducible protein-10, and regulated activation of normal T-cell expressed and secreted (RANTES). These results suggest that ILG can modulate TRIF-dependent signaling pathways of TLRs, leading to decreased inflammatory gene expression. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) play a critical role in sensing microbial components and inducing innate immune and inflammatory responses by recognizing invading microbial pathogens. Lipopolysaccharide-induced dimerization of TLR4 is required for the activation of downstream signaling pathways including nuclear factor-kappa B (NF-κB). Therefore, TLR4 dimerization may be an early regulatory event in activating ligand-induced signaling pathways and induction of subsequent immune responses. Here, we report biochemical evidence that 6-shogaol, the most bioactive component of ginger, inhibits lipopolysaccharide-induced dimerization of TLR4 resulting in the inhibition of NF-κB activation and the expression of cyclooxygenase-2. Furthermore, we demonstrate that 6-shogaol can directly inhibit TLR-mediated signaling pathways at the receptor level. These results suggest that 6-shogaol can modulate TLR-mediated inflammatory responses, which may influence the risk of chronic inflammatory diseases. [ABSTRACT FROM AUTHOR]

Abstract Toll-like receptors (TLRs) play a crucial role in the induction of innate immune response against bacterial and viral infections. TLRs induce downstream signaling via MyD88- and TRIF-dependent pathways. Cardamonin is a naturally occurring chalcone from Alpinia species exhibiting anti-inflammatory effects. However, the principal molecular mechanisms remain unclear. The objective of this study was to investigate the role of cardamonin in TLR signaling pathways. Cardamonin inhibited NF-κB activation as well as COX-2 expression induced by TLR agonists. Cardamonin inhibited the activation of IRF3 and the expression of interferon-inducible protein-10 (IP-10) induced by TLR3 or TLR4 agonists. Cardamonin also inhibited ligand-independent NF-κB activation overexpressed by MyD88, IKKβ, or p65 and IRF3 activation overexpressed by TRIF, TBK1, or IRF3. However, cardamonin had no effect on TBK1 kinase activity in vitro. These results suggest that cardamonin modulates both the MyD88- and TRIF-dependent pathways of TLRs and represents a potentially new anti-inflammatory candidate. Highlights • Toll-like receptors (TLR) play a significant role in the induction of innate immune responses. • Cardamonin is a naturally occurring chalcone from Alpinia species exhibiting anti-inflammatory effects. • Cardamonin suppressed the activation of IRF3 and the expression of IP-10 induced by TLR3 or TLR4 agonists. • These results demonstrate that cardamonin is a potential therapeutic candidate in the treatment of inflammatory diseases. [ABSTRACT FROM AUTHOR]

Abstract: Toll‐like receptors (TLRs) induce an innate immune system. In general, there are two main pathways in TLRs: the myeloid differentiation primary response protein 88 (MyD88)‐dependent and toll‐interleukin‐1 receptor domain‐containing adapter‐inducing interferon‐β (TRIF)‐dependent pathways. In this study, it has been investigated whether eicosapentaenoic acid (EPA), a polyunsaturated fatty acid (PUFA), and arachidic acid (ACA), a saturated fatty acid (SFA), can modulate the TLR signaling pathways. EPA suppressed the activation of interferon regulatory factor 3 (IRF3) and the expression of Interferon gamma‐induced protein (IP‐10) induced by Toll‐like receptor 3 (TLR3) or TLR4 agonists by targeting TANK‐binding kinase 1 (TBK1); however, ACA did not. These results demonstrate that EPA inhibits the TRIF‐dependent signaling in the TLR3 and TLR4 pathways. The results raise the possibility that certain dietary PUFAs can modulate TLR‐derived signaling and inflammatory target gene expression and can alter the susceptibility to microbial infection and chronic inflammatory diseases. Practical application: Eicosapentaenoic acid (EPA) is a bioactive lipid that modulates inflammation and immunity. TLRs play a central role as initiators of the innate immune responses. EPA regulates TRIF‐dependent pathways of TLRs by targeting TBK1. EPA may be a useful strategy to understand the mechanism of antiinflammatory activities. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) play a crucial role in danger recognition and induction of innate immune response against bacterial and viral infections. The TLR adaptor molecule, toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF), facilitates TLR3 and TLR4 signaling, leading to the activation of the transcription factor, NF-κB and interferon regulatory factor 3 (IRF3). Andrographolide, the active component of Andrographis paniculata , exerts anti-inflammatory effects; however, the principal molecular mechanisms remain unclear. The objective of this study was to investigate the role of andrographolide in TLR signaling pathways. Andrographolide suppressed NF-κB activation as well as COX-2 expression induced by TLR3 or TLR4 agonists. Andrographolide also suppressed the activation of IRF3 and the expression of interferon inducible protein-10 (IP-10) induced by TLR3 or TLR4 agonists. Andrographolide attenuated ligand-independent activation of IRF3 following overexpression of TRIF, TBK1, or IRF3. Furthermore, andrographolide inhibited TBK1 kinase activity in vitro . These results indicate that andrographolide modulates the TRIF-dependent pathway of TLRs by targeting TBK1 and represents a potential new anti-inflammatory candidate. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) play critical roles in the induction of immune and inflammatory responses by recognizing invading microbial pathogens. One of the most important proteins for inflammatory responses is inducible nitric oxide synthase (iNOS). The dysregulated iNOS activation play important roles in the development of certain inflammatory diseases. The present study investigated the effects of arachidic acid (ACA), which is a saturated fatty acid (SFA), and eicosapentanoic acid (EPA), which is polyunsaturated fatty acid (PUFA), on inflammation by modulating NF-κB activation and iNOS expression induced by TLRs agonists in murine macrophages. EPA suppressed NF-κB activation and iNOS expression induced by a lipopolysaccharide, macrophage-activating lipopeptide 2-kDa, and polyriboinosinic polyribocytidylic acid, but ACA did not. These results suggested that EPA can modulate TLR signaling pathways and subsequent chronic inflammatory responses, but ACA did not mediate these effects. All the results suggest that EPA is a promising novel agent for the treatment of inflammatory diseases. [ABSTRACT FROM AUTHOR]

Inflammation is a pathological process that is known to be involved in numerous diseases. Microbial infection or tissue injury activates inflammatory responses, resulting in the induction of proinflammatory proteins including cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS).Aster yomenais used in traditional Korean remedies to treat cough, asthma, and insect bites. Here, we investigated the effects ofA. yomenaextract (EAY) on the expression of COX-2 and iNOS induced by LPS. EAY inhibited NF-κB activation and IκBα degradation induced by LPS. EAY suppressed LPS-induced COX-2 and iNOS expression which are the target genes regulated through NF-κB activation in macrophages. EAY also suppressed LPS-induced nitrite production. These results suggest that EAY has the potential to be developed as a potent anti-inflammatory drug. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) play significant roles in recognizing the pathogen-associated molecular patterns that induce innate immunity, and subsequently, acquired immunity. In general, TLRs have two downstream signaling pathways, the myeloid differential factor 88 (MyD88)-dependent and toll-interleukin-1 receptor domain-containing adapter-inducing interferon-β (TRIF)-dependent pathways, which lead to the activation of nuclear factor-kappa B (NF-κB) and interferon regulatory factor 3 (IRF3). 1-[5-methoxy-2-(2-nitrovinyl)phenyl]pyrrolidine (MNP) has been previously synthesized in our laboratory. To evaluate the therapeutic potential of MNP, its effect on signal transduction via the TLR signaling pathways was examined. MNP was shown to inhibit the activation of NF-κB and IRF3 induced by TLR agonists, as well as to inhibit the expression of cyclooxygenase-2, inducible nitric oxide synthase, and interferon inducible protein-10. MNP also inhibited the activation of NF-κB and IRF3 induced by the overexpression of downstream signaling components of the MyD88- or TRIF-dependent signaling pathways. These results suggest that MNP can modulate MyD88- and TRIF-dependent signaling pathways of TLRs, leading to decreased inflammatory gene expression. [ABSTRACT FROM AUTHOR]

Toll-like receptor 4 (TLR4) recognizes LPS and triggers the activation of the myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter, inducing interferon-β (TRIF)-dependent major downstream signaling pathways. Previously, we presented biochemical evidence that 1-[4-Fluoro-2-(2-nitrovinyl)phenyl]pyrrolidine (FPP), which was synthesized in our laboratory, inhibits NF-κB activation induced by LPS. Here, we investigated whether FPP modulates the TLR4 downstream signaling pathways and what anti-inflammatory target in TLR4 signaling is regulated by FPP. FPP inhibited LPS-induced NF-κB activation by targeting TLR4 dimerization. These results suggest that FPP can modulate the TLR4 signaling pathway at the receptor level to decrease inflammatory gene expression. [ABSTRACT FROM PUBLISHER]

Toll-like receptors (TLRs) recognize microbial molecules that are widely presented by pathogens and initiate the innate immune system. TLR signaling is divided into two different signaling pathways, the myeloid differential factor 88 (MyD88)- and Toll/interleukin-1 receptor domain-containing adapter inducing interferon-β(TRIF)-dependent pathways.Eupatorium makinoi, a plant species inAsteraceae, is used for medicinal purposes in China, Korea, and Japan. Through our previous research, we found that an ethanol extract ofE. makinoi(EEM) suppresses inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. In this study, we investigated the effect of EEM on TLRs signaling pathways. EEM suppresses NF-κB activation and iNOS and COX-2 expressions induced by TLR2 or TLR4 agonists. Also, EEM suppresses the activation of interferon (IFNs) regulatory factor 3 (IRF3) induced by TLR3 or TLR4 agonists. All results indicate that EEM suppresses myeloid differentiation primary-response protein 88 (MyD88) and TRIF-dependent signaling pathways of TLRs and the expressions of target genes derived from the activation of TLRs [ABSTRACT FROM PUBLISHER]

Toll-like receptors (TLRs) recognize distinct pathogen-associated molecular patterns and play a critical role in innate immune responses. TLR signaling pathways can be largely classified as either myeloid differential factor 88 (MyD88)- or toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent pathways. C ompound of Designation red 10 binding ( CDr10b ) was synthesized to investigate its role in neuroinflammatory diseases. This study was conducted to determine whether CDr10b can affect TLR signaling pathways. CDr10b suppressed NF-κB activation as well as COX-2 and iNOS expression induced by TLR3 or TLR4 agonists. CDr10b also suppressed the activation of interferon regulatory factor 3 (IRF3) and the expression of interferon inducible protein-10 (IP-10) induced by TLR3 or TLR4 agonists. These results indicate that CDr10b can modulate the TRIF-dependent pathway of TLRs and has the potential to become a new therapeutic drug for chronic inflammatory diseases. [ABSTRACT FROM AUTHOR]

Inflammation is involved in numerous diseases including cancer. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) play important roles in the development of certain inflammatory diseases.Eupatorium makinoi, which belongs to a family ofAsteraceaeplants, is used medicinally in East Asia. We investigated the effects of an ethanol extract ofE. makinoi(EEM) on nuclear factor-kappa B (NF-κB) activation and the expression of iNOS and COX-2 with lipopolysaccharide (TLR4 agonist) in murine macrophages. EEM suppressed NF-κB activation and iNOS and COX-2 expression induced by LPS. These results suggest that EEM may regulate TLR4 signalling pathways and this may be a useful strategy for anti-inflammatory therapies. [ABSTRACT FROM PUBLISHER]

The pathophysiological processes of inflammation can lead to a host of diseases, such as periodontitis, atherosclerosis, rheumatoid arthritis, and even cancer. The dysregulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) activation play important roles in the development of certain inflammatory diseases. Here, we investigated the effects of CDr10b which is originally developed for a microglia staining probe on inflammation, by modulating NF-κB activation and iNOS and COX-2 expression induced by lipopolysaccharide (LPS) in murine macrophages. The CDr10b suppressed NF-κB activation and iNOS and COX-2 expression induced by LPS. All the results suggest that CDr10b is a promising novel agent for the treatment of inflammatory diseases. [ABSTRACT FROM AUTHOR]

Abstract: Toll-like receptors (TLRs) play an important role in the recognition of microbial pathogens and induce innate immune responses. The recognition of microbial components by TLRs triggers the activation of myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent downstream signaling pathways. Previously, we synthesized (E)-1-(2-(2-nitrovinyl)phenyl)pyrrolidine (NVPP), which contains a nitrovinyl-phenyl and pyrrolidine. To evaluate the therapeutic potential of NVPP, its effect on signal transduction via the TRIF-dependent pathway of TLRs induced by lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly[I:C]) was examined. NVPP inhibited LPS or poly[I:C]-induced activation of nuclear factor-κB (NF-κB) and interferon regulatory factor 3 (IRF3), and the phosphorylation of IRF3, as well as inhibiting the activation of interferon-inducible genes such as interferon inducible protein-10 (IP-10). These results suggest that NVPP can modulate TRIF-dependent signaling pathways of TLRs, potentially resulting in effective therapeutics for chronic inflammatory diseases. [Copyright &y& Elsevier]

Abstract: Toll-like receptors (TLRs) recognize many pathogen-associated molecular patterns and induce innate immunity. TLR signaling pathways induce the activation of various transcription factors, such as nuclear factor-κB (NF-κB), leading to the induction of pro-inflammatory gene products, such as inducible nitric oxide synthase (iNOS). Here, we investigated the effect of an (E)-1-(2-(2-nitrovinyl)phenyl)pyrrolidine (NVPP), previously synthesized in our laboratory, on inflammation by modulating NF-κB activation and iNOS expression induced by TLR agonists in murine macrophages. NVPP suppressed NF-κB activation and iNOS expression induced by lipopolysaccharide (TLR4 agonist), polyriboinosinic polyribocytidylic acid (TLR3 agonist), and macrophage-activating lipopeptide 2kDa (TLR2 and TLR6 agonist). All the results suggest that NVPP is suitable for development as a new anti-inflammatory drug. [Copyright &y& Elsevier]

Abstract: Aims: The aim of this study was to evaluate the therapeutic potential of the phenethyl isothiocyanate (PEITC) in Toll-like receptor (TLR) signaling pathways. Main methods: To evaluate the cytotoxic nature of PEITC in RAW 264.7 cells, cytotoxicity was determined using the MTS cell viability assay. RAW264.7 cells were transfected with a nuclear factor-κB (NF-κB), interferon β (IFNβ) PRDIII-I, or interferon inducible protein-10 (IP-10) luciferase plasmid and then luciferase enzyme activities were determined by luciferase assay. The expression of inducible nitric oxide synthase (iNOS) and phosphorylation of interferon regulatory factor 3 (IRF3) were determined by Western blotting. The levels of IP-10 were determined with culture medium by using an IP-10 enzyme-linked immunosorbent assay (ELISA) kit. Key findings: PEITC suppressed the activation of IRF3 and the expression of IP-10 induced by lipopolysaccharide (LPS) or polyinosinic–polycytidylic acid (poly[I:C]). Significance: TLRs play an important role in the induction of innate immune responses for host defense against invading microbial pathogens. PEITC found in cruciferous vegetables has an effect on treatment of many chronic diseases. Our results suggest that beneficial effects of PEITC on chronic inflammatory diseases are mediated through modulation of Toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent signaling pathway of TLRs. [Copyright &y& Elsevier]

Abstract: Toll-like receptors (TLR) play a significant role in the induction of innate immune responses that are essential for host defense against invading microbial pathogens. In general, TLRs have two major downstream signaling pathways: myeloid differential factor 88 (MyD88)-dependent and toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent pathways. Allyl isothiocyanate (AITC) found in cruciferous vegetables has an effect on treatment of many chronic diseases. However, the exact molecular targets of AITC are still unidentified. Here, it was investigated whether AITC can modulate TLR signaling pathways and what is the molecular target of AITC in TLRs signaling pathways. AITC suppressed the activation of nuclear factor-κB by lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly[I:C]), but not by macrophage-activating lipopeptide of 2kDa (MALP-2) or cytosine-phosphate-guanine dinucleotide (CpG DNA). AITC also suppressed the activation of interferon regulatory factor 3 (IRF3) and the expression of interferon inducible protein-10 (IP-10) induced by LPS or poly[I:C]. These results suggest that AITC can modulate TRIF-dependent signaling pathways of TLRs leading to decreased inflammatory gene expression. [Copyright &y& Elsevier]

Abstract: IS2, a soluble β-glucan isolated from the cell wall of mutated Saccharomyces cerevisiae (S. cerevisiae) enhances the immune response compared to the wild type (WT) β-glucan. In the present investigation we report that Toll-like receptor (TLR)/MyD88 signaling pathway was responsible in IS2 β-glucan-mediated cellular response in RAW264.7 murine macrophages. Data revealed that IS2 β-glucan significantly up-regulated the TLR2/TLR4 expression. Moreover, TLR2/TLR4 responds to IS2 resulting in murine macrophage activation. In addition, the IS2 signal led to cytokine secretions of IL-6 and TNF-α. In the case of thioglycolate-elicited peritoneal macrophages from MyD88-deficient mice, the decrease in cytokines was observed. Further the mitogen-activated protein kinases (MAPKs) phosphorylation was evident and degradation of IκB-α was increased after stimulation with IS2 β-glucan. Further examination with MyD88-deficient mice revealed that the MyD88 pathway might play an important role for IS2 β-glucan-mediated activation of macrophages. [Copyright &y& Elsevier]

Abstract: Toll-like receptors (TLRs) recognize molecular structures derived from microbes and initiate innate immunity. The stimulation of TLR4 by lipopolysaccharide (LPS) triggers the activation of the myeloid differential factor 88 (MyD88)-dependent and toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent major downstream signaling pathways. Previously, we synthesized a fumaryl oxazolidinone derivative, 4-oxo-4-(2-oxo-oxazolidin-3-yl)-but-2-enoic acid ethyl ester (OSL07) and demonstrated that it inhibits activation of nuclear factor kappa B (NF-κB) by inhibiting the MyD88-dependent pathway of TLRs. TLR4 and the downstream signaling components are good therapeutic targets for many chronic inflammatory diseases. Here, it is investigated whether OSL07 modulates TLR4 downstream signaling pathways and what anti-inflammatory target in TLR4 signaling is regulated by OSL07. OSL07 inhibited LPS-induced NF-κB and interferon regulatory factor 3 activation by targeting TLR4 dimerization. These results suggest that OSL07 can modulate TLR4 signaling pathway leading to decreased inflammatory gene expression. [ABSTRACT FROM AUTHOR]

Abstract: Toll-like receptors (TLRs) recognize molecular structures derived from microbes including bacteria, viruses, yeast, and fungi, and regulate the activation of innate immunity. All TLR signaling pathways culminate in the activation of nuclear factor-κB (NF-κB) transcription factor leading to the induction of inflammatory gene products including cytokines and cyclooxygenase-2 (COX-2). In the present report, we demonstrate biochemical evidence that the fumaryl oxazolidinone derivative 4-Oxo-4-(2-oxo-oxazolidin-3-yl)-but-2-enoic acid ethyl ester (OSL07), which was previously synthesized in our laboratory, inhibits the NF-κB activation induced by TLR agonists and overexpression of downstream signaling components of TLRs, MyD88 and IKKβ. OSL07 also inhibits TLR agonist-induced COX-2 expression. These results indicate that the anti-inflammatory effects of OSL07 are caused by the modulation of the immune responses regulated by TLR signaling pathways. [Copyright &y& Elsevier]

• TLRs play a significant role in the induction of innate immune responses. • DHL, a natural sesquiterpene lactone, modulates TLR signaling pathways. • DHL is a potential therapeutic candidate in the treatment of inflammatory diseases. Toll-like receptors (TLRs) are a group of pattern-recognition receptors (PRRs) that are at the core of innate and adaptive immune responses. TLRs activation triggers the activation of two downstream signaling pathways, the myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent pathways. To evaluate the therapeutic potential of DHL, a natural sesquiterpene lactone derived from Inulahelenium L. and Saussurea lappa, we examined its effect on signal transduction via the TLR signaling pathways. DHL inhibited the activation of nuclear factor-κB (NF-κB) and interferon regulatory factor 3 (IRF3), the representative transcription factors involved in the inflammatory response, induced by TLR agonists, as well as the expression of cyclooxygenase-2 and interferon inducible protein-10. DHL also inhibited the activation of NF-κB and IRF3 induced by the overexpression of downstream signaling components of the TLRs signaling pathways. All results suggest that DHL might become a new therapeutic drug for a variety of inflammatory diseases. [ABSTRACT FROM AUTHOR]