• Journal of Nutrition and Health
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• v.49 no.4
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• pp.241-246
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• 2016

Purpose: Aloe-emodin (AE), an ingredient of aloe, is known to exhibit anti-inflammatory activities. However, little is known about the underlying molecular mechanisms of its inflammatory modulatory activity in vitro. In the present study, we investigated the anti-inflammatory potential of AE using $Pam_3CSK_4$-stimulated macrophages. Methods: RAW 264.7 macrophages were treated with AE (0~20 mM) for 1 h, followed by treatment with $Pam_3CSK_4$ for 1 h. After incubation, mRNA expression levels of cytokines were measured. The effect of AE on TLR2-related molecules was also investigated in $Pam_3CSK_4$-stimulated RAW 264.7 macrophages. Results: AE attenuated $Pam_3CSK_4$-stimulated expression of proinflammatory cytokines, including tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-6 (IL-6), and interleukin-$1{\beta}$ ($IL-1{\beta}$) in RAW 264.7 macrophages. Two concentrations of AE ($10{\mu}M$ and $20{\mu}M$) effectively reduced mRNA expression of TLR2 by 41.18% and 54.43%, respectively, compared to that in control cells (p < 0.05). AE also decreased nuclear factor-kappa B ($NF-{\kappa}B$) activation and mitogen-activated protein kinase (MAPK) phosphorylation. Phosphorylation levels of ERK1/2, p38, and JNK were markedly reduced by $20{\mu}M$ AE. In particular, AE decreased phosphorylation of ERK in a dose-dependent manner in $Pam_3CSK_4$-stimulated RAW 264.7 macrophages. Conclusion: Our data indicate that AE exerts its anti-inflammatory effect by suppressing TLR2-mediated activation of $NF-{\kappa}B$ and MAPK signaling pathways in macrophages.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.315-323
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• 2008

In the previous studies, we isolated the compound K rich fractions (CKRF) and showed that CKRF inhibited Toll-like receptor (TLR) 4- or TLR9-induced inflammatory signaling. To extend our previous studies,1) we investigated the molecular mechanisms of CKRF in the TLR4-associated signaling via nuclear factor (NF)-${\kappa}B$, and in vivo role of CKRF for induction of tolerance in lipopolysaccharide (LPS)-induced septic shock. In murine bone marrow-dervied macrophages, CKRF significantly inhibited the induction of mRNA expression of proinflammatory mediators such as tumor necrosis factor-${\alpha}$, interleukin-6, cyclooxygenase-2, and inducible nitric oxide synthase. In addition, CKRF significantly attenuated the transcriptional activities of TLR4/LPS-induced NF-${\kappa}B$. Nuclear translocation of NF-${\kappa}B$ in response to LPS stimulation was significantly abrogated by pre-treatment with CKRF. Furthermore, CKRF inhibited the recruitment of p65 to the interferon-sensitive response element flanking region in response to LPS. Finally, oral administration of CKRF significantly protected mice from Gram-negative bacterial LPS-induced lethal shock and inhibited systemic inflammatory cytokine levels. Together, these results demonstrate that CKRF modulates the TLR4-dependent NF-${\kappa}B$ activation, and suggest a therapeutic role for Gram-negative septic shock.

• Biomedical Science Letters
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• v.21 no.3
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• pp.152-159
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• 2015

Der p 2, which is a major allergen of house dust mite, plays an important role in the pathogenesis of allergic disease. There is controversy regarding whether Der p 2 binds to Toll-like receptor 4 (TLR4), and its inflammatory effect has not yet been elucidated. In the current study, we examined the interaction of Der p 2 with TLR4 and the effect of Der p 2 on cytokine release in THP-1 cells and lymphocytes. Among house dust mite extracts, recombinant TLR4 protein interacted with Der p 2. The overall structure of Der p 2 is characteristic of the immunoglobulin superfamily and contains ten ${\beta}-strands$, forming a ${\beta}-cup$ fold with two anti-parallel ${\beta}-sheets$, and a short 310 helix. The two sheets can be separated, further allowing the formation of a large internal pocket, which is narrow and suitable for binding large flat molecules such as lipid-like molecules. Der p 2 caused increased secretion of IL-6, IL-8, and MCP-1, which are neutrophil survival factors, in human monocytic THP-1 cells in a time-dependent manner. Der p 2 also induces the release of cytokines in normal and allergic lymphocytes. Supernatant after treatment with Der p 2 inhibited neutrophil apoptosis. In coculture of lymphocytes with neutrophils, Der p 2 inhibited spontaneous apoptosis of allergic neutrophils. In summary, Der p 2 binds to TLR4 and induces an inflammatory response such as cytokine secretion in immune cells. These findings may enable elucidation of allergy pathogenesis by specific allergen of house dust mite.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5867-5872
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• 2014

Background: Cervical cancer is listed as one of high-incidence endemic diseases in Xinjiang. Our study aimed to evaluate the expression of TLR9 in uterine cervical tissues of Uyghur women and examine associations with clinicopathological variables. We further characterized the direct effects of TLR9 upon the selective silencing of human papillomavirus (HPV) E6 and E7 oncoprotein expression in HPV 16-positive human cervical carcinoma cells treated with siRNA in vitro. Materials and Methods: Immunohistochemistry was applied to evaluate TLR9 expression in 97 formalin-fixed paraffin-embedded cervical samples from Uyghur women; 32 diagnosed with cervical squamous cell carcinomas (CSCC), 14 with low-grade cervical intraepithelial neoplasias (CINI), 10 medium-grade (CINII), 24 high-grade (CINIII), and 17 chronic cervicitis. $BLOCK-iT^{TM}$ U6 RNAi Entry Vector $pENTR^{TM}$/U6-E6 and E7 was constructed and transfected the entry clone directly into the mammalian cell line 293FT. Then the HPV 16-positive SiHa human cervical carcinoma cell line was infected with RNAi recombinant lentivirus. RT-PCR and Western blotting were used to determine the expression of TLR9 in both SiHa and HPV 16 E6 and E7 silenced SiHa cells. Results: Immunohistochemical staining showed that TLR9 expression was undetectable (88.2%) or weak (11.8%) in chronic cervicitis tissues. However, variable staining was observed in the basal layer of all normal endocervical glands. TLR9 expression, which was mainly observed as cytoplasmic staining, gradually increased in accordance with the histopathological grade in the following order: chronic cervicitis (2/17, 11.8%)

• The Korea Journal of Herbology
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• v.21 no.3
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• pp.103-109
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• 2006

Objectives : The purpose of this study was to investigate the TLR-4 mediated anti-inflammatory effects of extract from Xanthii Fructus(XF) on the peritoneal macrophage. Methods : To evaluate of TLR-4 mediated inflammatory of XF, we examined NO and cytokine production in TRL-4 ligand(LPS-lipopolysacchride) induced macrophages. Furthermore, we checked molecular mechanism using western blot. Results : l.Extract from XF reduced LPS-induced Nitric oxide (NO), tumor necrosis factor-a (TNF-a), interleukin (IL)-6 and IL-12 production in peritoneal macrophages 2.Extract from XF itself does not have any cytotoxic effect.XS inhibited degradation of IkBa in the TLR-4 mediated peritoneal macrophages Conclusion : XF down-regulated TLR4 ligand(LPS)-induced NO and cytokine productions.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.1
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• pp.29-39
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• 2020

In this study, we investigated the inhibitory potential of an ethanol extract of Carpomitra costata (EECC) (Stackhouse) Batters, a brown alga, against neuroinflammatory responses in lipopolysaccharide (LPS)-stimulated BV2 microglia. Our results showed that EECC significantly suppressed the LPS-induced secretion of pro-inflammatory mediators, including nitric oxide (NO) and prostaglandin E₂, with no significant cytotoxic effects. EECC also inhibited the LPS-induced expression of their regulatory enzymes, such as inducible NO synthase and cyclooxygenase-2. In addition, EECC downregulated the LPS-induced expression and production of the proinflammatory cytokines, tumor necrosis factor-α and interleukin-1β. In the mechanistic assessment of the antineuroinflammatory effects, EECC was found to inhibit the nuclear translocation and DNA binding of nuclear factor-kappa B (NF-κB) by disrupting the degradation of the κB-α inhibitor in the cytoplasm. Moreover, EECC effectively suppressed the enhanced expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88, as well as the binding of LPS to TLR4 in LPS-treated BV2 cells. Furthermore, EECC markedly reduced the LPS-induced generation of reactive oxygen species (ROS), demonstrating a strong antioxidative effect. Collectively, these results suggest that EECC repressed LPS-mediated inflammatory action in the BV2 microglia through the inactivation of NF-κB signaling by antagonizing TLR4 and/or preventing ROS accumulation. While further studies are needed to fully understand the anti-inflammatory effects associated with the antioxidant activity of EECC, the current findings suggest that EECC has a potential advantage in inhibiting the onset and treatment of neuroinflammatory diseases.

• Molecules and Cells
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• v.25 no.2
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• pp.253-257
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• 2008

Acrolein is a highly electrophilic ${\alpha},{\beta}$-unsaturated aldehyde present in a number of environmental sources, especially cigarette smoke. It reacts strongly with the thiol groups of cysteine residues by Michael addition and has been reported to inhibit nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) activation by lipopolysaccharide (LPS). The mechanism by which it inhibits $NF-{\kappa}B$ is not clear. Toll-like receptors (TLRs) play a key role in sensing microbial components and inducing innate immune responses, and LPS-induced dimerization of TLR4 is required for activation of downstream signaling pathways. Thus, dimerization of TLR4 may be one of the first events involved in activating TLR4-mediated signaling pathways. Stimulation of TLR4 by LPS activates both myeloid differential factor 88 (MyD88)- and TIR domain-containing adapter inducing $IFN{\beta}$ (TRIF)-dependent signaling pathways leading to activation of $NF-{\kappa}B$ and IFN-regulatory factor 3 (IRF3). Acrolein inhibited $NF-{\kappa}B$ and IRF3 activation by LPS, but it did not inhibit $NF-{\kappa}B$ or IRF3 activation by MyD88, inhibitor ${\kappa}B$ kinase $(IKK){\beta}$, TRIF, or TNF-receptor-associated factor family member-associated $NF-{\kappa}B$ activator (TANK)-binding kinase 1 (TBK1). Acrolein inhibited LPS-induced dimerization of TLR4, which resulted in the down-regulation of $NF-{\kappa}B$ and IRF3 activation. These results suggest that activation of TLRs and subsequent immune/inflammatory responses induced by endogenous molecules or chronic infection can be modulated by certain chemicals with a structural motif that enables Michael addition.

• Toxicological Research
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• v.31 no.1
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• pp.11-16
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• 2015

Our body's immune system has defense mechanisms against pathogens such as viruses and bacteria. Immune responses are primarily initiated by the activation of toll-like receptors (TLRs). In particular, TLR4 is well-characterized and is known to be activated by gram-negative bacteria and tissue damage signals. TLR4 requires myeloid differentiation factor 2 (MD2) as a co-receptor to recognize its ligand, lipopolysaccharides (LPS), which is an extracellular membrane component of gram-negative bacteria. Gambogic acid is a xanthonoid isolated from brownish or orange resin extracted from Garcinia hanburyi. Its primary effect is tumor suppression. Since inflammatory responses are related to the development of cancer, we hypothesized that gambogic acid may regulate TLR4 activation. Our results demonstrated that gambogic acid decreased the expression of pro-inflammatory cytokines ($TNF-{\alpha}$, IL-6, IL-12, and $IL-1{\beta}$) in both mRNA and protein levels in bone marrow-derived primary macrophages after stimulation with LPS. Gambogic acid did not inhibit the activation of Interferon regulatory factor 3 (IRF3) induced by TBK1 overexpression in a luciferase reporter gene assay using IFN-${\beta}$-PRD III-I-luc. An in vitro kinase assay using recombinant TBK1 revealed that gambogic acid did not directly inhibit TBK1 kinase activity, and instead suppressed the binding of LPS to MD2, as determined by an in vitro binding assay and confocal microscopy analysis. Together, our results demonstrate that gambogic acid disrupts LPS interaction with the TLR4/MD2 complex, the novel mechanism by which it suppresses TLR4 activation.

• IMMUNE NETWORK
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• v.11 no.6
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• pp.420-423
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• 2011

Since CKD-712 has been developed as an anti-inflammatory agent, we examined the effect of CKD-712 during TLR4 signaling. Using HEK293 cells expressing TLR4, CKD-712 was pre-treated 1 hr before LPS stimulation. Activation of NF-${\kappa}B$ was assessed by promoter assay. The activation of ERK, JNK, p38, IRF3 and Akt was measured by western blotting. CKD-712 inhibited the NF-${\kappa}B$ signaling triggered by LPS. The activation of ERK, JNK, p38 or IRF3 was not inhibited by CKD-712. On the contrary the activation of these molecules was augmented slightly. The activation of Akt with stimulation of LPS was also enhanced with CKD-712 pre-treatment at lower concentration, but was inhibited at higher concentration. We suggest that during TLR4 signaling CKD-712 inhibits NF-${\kappa}B$ activation. However, CKD-712 augmented the activation of Akt as well as Map kinases. Therefore, we suggest that CKD-712 might have a role as an immunomodulator.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.3
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• pp.217-225
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• 2021

Neuropathic pain (NP) that contributes to the comorbidity between pain and depression is a clinical dilemma. Neuroinflammatory responses are known to have potentially important roles in the initiation of NP and depressive mood. In this study, we aimed to investigate the effects of paeoniflorin (PF) on NP-induced depression-like behaviors by targeting the hippocampal neuroinflammation through the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway. We used a murine model of NP caused by unilateral sciatic nerve cuffing (Cuff). PF was injected intraperitoneally once a day for a total of 14 days. Pain and depression-like behavior changes were evaluated via behavioral tests. Pathological changes in the hippocampus of mice were observed by H&E staining. The levels of proinflammatory cytokines in the hippocampus were detected using ELISA. Activated microglia were measured by immunohistochemical staining. The TLR4/NF-κB signaling pathway-associated protein expression in the hippocampus was detected by western blotting. We found that the PF could significantly alleviate Cuff-induced hyperalgesia and depressive behaviors, lessen the pathological damage to the hippocampal cell, reduce proinflammatory cytokines levels, and inhibit microglial over-activation. Furthermore, PF downregulated the expression levels of TLR4/NF-κB signaling pathway-related proteins in the hippocampus. These results indicate that PF is an effective drug for improving the comorbidity between NP and depression.