• Title/Summary/Keyword: $NF-{\kappa}B$ activation

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The Shigella Flexneri Effector OspG Interferes with Innate Immune Responses by Targeting Ubiquitin-Conjugating Enzymes

  • Kim, Dong-Wook
    • Proceedings of the PSK Conference
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    • 2005.11a
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    • pp.231-232
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    • 2005
  • Bacteria of Shigella spp. are responsible for shigellosis in humans, a disease characterized by destruction of the colonic epithelium that is induced by the inflammatory response elicited by invasive bacteria. They use a type III secretion system injecting effector proteins into host cells to induce their entry into epithelial cells and triggers apoptosis in macrophages. We present evidence that the effector OspG is a protein kinase that binds various ubiquitinylated ubiquitin-conjugating enzymes (E2s) and blocks degradation of phospho-$I{\kappa}B{\alpha}$ induced upon entry of bacteria into epithelial cells. Transfection experiments confirmed that OspG interferes with the $NF-{\kappa}B$ activation patway by preventing phospho-$I{\kappa}B{\alpha}$ degradation, suggesting that OspG inactivates a component of the $SCF^{{\beta}-TrCP}$ ubiquitin ligase complex (E3) involved in phospho-$I{\kappa}B{\alpha}$ ubiquitination. Upon infection of ileal loops in rabbits, the ospG mutant induced a stronger inflammatory response compared with the wild-type strain, indicating that OspG down-regulates the host innate response induced by invasive bacteria.

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Inhibitory Effect of the Rodgersia podophylla Leave Extracts against Cell Proliferation through Activation of NF-κB in Human Colorectal Cancer Cells (도깨비부채 잎 추출물의 NF-κB 활성화를 통한 대장암 세포 HCT116에 대한 세포생육 억제활성)

  • Kim, Jeong Dong;Jeong, Jin Boo
    • Korean Journal of Plant Resources
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    • v.33 no.5
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    • pp.460-466
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    • 2020
  • In this study, we evaluated the anti-cancer activity and potential molecular mechanism of 70% ethanol extracts of leaves from Rodgersia podophylla against human colorectal cancer cells, HCT116. RPL dose-dependently decreased the cell viability through RPL-induced apoptosis in HCT116 cells. RPL induced inactivation the nuclear factor κB(NF-κB) through blocking IκB-α degradtion and P65 nuclear accumulation. The inhibition of GSK3β by LiCl attenuated RP-L-mediated NF-κB signaling inactivation. In addition, RP-L induced GSK3β activation. Based on these findings, RPL may be a potential candidate for the development of chemopreventive or therapeutic agents for human colorectal cancer.

The Effect of Silibinin Extracted from Cirsium Japonicum on Allergic Inflammation (대계(大薊)의 주성분인 Silibinin이 알레르기 염증반응에 미치는 효과(效果))

  • Kim, Beom-Rak;Kim, Koung-Jun
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.23 no.1
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    • pp.44-58
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    • 2010
  • Silibinin is the major active molecule of silymarin, the mixture of flavonolignans extracted from Cirsium japonicum (CJ). It has been used for treatment of hepatitis and inflammation related diseases. The aim of this study was to prove whether Silibinin has effectiveness for allergic inflammation. Silibinin processes the inflammatory reaction in phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187 (PMA plus A23187) stimulated human mast cell line (HMC-1). Its effect was examined by ELISA, RT-PCR, Western blot, and Luciferase assay. The results were Silibinin inhibited the expression of histamine, TNF-$\alpha$ (tumor necrosis factor-$\alpha$), IL-6 (interleukin-6), and IL-8 (interleukin-8). Silibinin suppressed NF-${\kappa}B$ (nuclear factor kappa B) activation in stimulated HMC-1 (human mast cell-1). This effect was mediated through inhibition of phosphorylation and degradation of $IkB{\alpha}$, an inhibitor of NF-kB. Silibinin significantly inhibited induction of NF-kB promoter mediated Luciferase assay. These results suggest that Silibinin has a potential molecule for therapy of mast cell-derived allergic inflammatory diseases.

Effects of troxerutin on vascular inflammatory mediators and expression of microRNA-146a/NF-κB signaling pathway in aorta of healthy and diabetic rats

  • Che, Xing;Dai, Xiang;Li, Caiying
    • The Korean Journal of Physiology and Pharmacology
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    • v.24 no.5
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    • pp.395-402
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    • 2020
  • This study has investigated the effect of a potent bioflavonoid, troxerutin, on diabetes-induced changes in pro-inflammatory mediators and expression of microRNA-146a and nuclear factor-kappa-B (NF-κB) signaling pathway in aortic tissue of type-I diabetic rats. Male Wistar rats were randomly divided into four groups (n = 6/each): healthy, healthy-troxerutin, diabetic, and diabetic-troxerutin. Diabetes was induced by streptozotocin injection (60 mg/kg; intraperitoneally) and lasted 10 weeks. Troxerutin (150 mg/kg/day) was administered orally for last month of experiment. Inflammatory cytokines IL-1β, IL-6, and TNF-α, as well as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule (VCAM), cyclooxygenase-II (COX-II), and inducible-nitric oxide synthase (iNOS) were measured on aortic samples by enzyme-linked immunosorbent assay. Gene expressions for transcription factor NF-κB, interleukin-1 receptor-associated kinase-1 (IRAK-1), TNF receptor-associated factor-6 (TRAF-6), and microRNA-146a were determined using real-time polymerase chain reaction. Ten-week diabetes significantly increased mRNA levels of IRAK-1, TRAF-6, NF-κB, and protein levels of cytokines IL-1β, IL-6, TNF-α, adhesion molecules ICAM-1, VCAM, and iNOS, COX-II, and decreased expression of microRNA-146a as compared with healthy rats (p < 0.05 to p < 0.01). However, one month treatment of diabetic rats with troxerutin restored glucose and insulin levels, significantly decreased expression of inflammatory genes and pro-inflammatory mediators and increased microRNA level in comparison to diabetic group (p < 0.05 to p < 0.01). In healthy rats, troxerutin had significant reducing effect only on NF-κB, TNF-α and COX-II levels (p < 0.05). Beside slight improvement of hyperglycemia, troxerutin prevented the activation of NF-κB-dependent inflammatory signaling in the aorta of diabetic rats, and this response may be regulated by microRNA-146a.

Triptolide improves myocardial fibrosis in rats through inhibition of nuclear factor kappa B and NLR family pyrin domain containing 3 inflammasome pathway

  • Shen, Jianyao;Ma, Hailiang;Wang, Chaoquan
    • The Korean Journal of Physiology and Pharmacology
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    • v.25 no.6
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    • pp.533-543
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    • 2021
  • Myocardial fibrosis (MF) is the result of persistent and repeated aggravation of myocardial ischemia and hypoxia, leading to the gradual development of heart failure of chronic ischemic heart disease. Triptolide (TPL) is identified to be involved in the treatment for MF. This study aims to explore the mechanism of TPL in the treatment of MF. The MF rat model was established, subcutaneously injected with isoproterenol and treated by subcutaneous injection of TPL. The cardiac function of each group was evaluated, including LVEF, LVFS, LVES, and LVED. The expressions of ANP, BNP, inflammatory related factors (IL-1β, IL-18, TNF-α, MCP-1, VCAM1), NLRP3 inflammasome factors (NLRP3, ASC) and fibrosis related factors (TGF-β1, COL1, and COL3) in rats were dete cted. H&E staining and Masson staining were used to observe myocardial cell inflammation and fibrosis of rats. Western blot was used to detect the p-P65 and t-P65 levels in nucleoprotein of rat myocardial tissues. LVED and LVES of MF group were significantly upregulated, LVEF and LVFS were significantly downregulated, while TPL treatment reversed these trends; TPL treatment downregulated the tissue injury and improved the pathological damage of MF rats. TPL treatment downregulated the levels of inflammatory factors and fibrosis factors, and inhibited the activation of NLRP3 inflammasome. Activation of NLRP3 inflammasome or NF-κB pathway reversed the effect of TPL on MF. Collectively, TPL inhibited the activation of NLRP3 inflammasome by inhibiting NF-κB pathway, and improved MF in MF rats.

Radio-sensitivity of Human Colorectal Cancer Cell is Regulated by Potassium Cyanate (Potassium cyanate에 의해 조절되는 사람 대장암 세포의 방사선 감수성 변화)

  • Yang, Eun Ju;Chang, Jeong Hyun
    • Journal of the Korean Society of Radiology
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    • v.13 no.1
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    • pp.125-132
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    • 2019
  • Potassium cyanate (KCN) is an inorganic reagent and can induce the post-translation carbamylation of proteins. The carbamylated reaction in the body is involved in cell death in various diseases. According the results in our previous study, KCN enhances the radiosensitivity of human colorectal cancer cell line, HCT 116 cells. However, it was not enough to confirm the mechanism that KCN works in these cells. To determinated the mechanisms of KCN in the cells with increased radiosensitivity, HCT 116 cells were treated KCN with low-dose gamma-radiation. And then, we examined alteration of the cell cycle, cell proliferation, cytokine level and the activation of cell signaling protein. As a result, cell cycle arrest and cell death were induced by the activation of caspase-3 and PARP in the irradiated cells with KCN treatment. These changes of the irradiated cell with KCN treatment were induced by the release of $TNF-{\alpha}$ via $NF-{\kappa}B$ activation. In conclusions, enhanced radio-sensitivity mediated by KCN induced cell death and it occurs by $NF-{\kappa}B$-dependent $TNF-{\alpha}$ production.

Effects and Efficacy of Natural Product on Infectious Diseases of pseudomonas aeruginosa (천연물 유래 물질이 감염성 질환에 미치는 영향과 효능)

  • Ji-Won Park
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2020.12a
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    • pp.3-13
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    • 2020
  • Pseudomonas aeruginosa is a ubiquitous gram-negative bacterium causing serious infections. The P. aeruginosa T3SS is a syringe-like apparatus on the bacterial surface, with 4 effector toxins: ExoS, ExoT, ExoY, and ExoU. Here, we investigated the effect of ExoS and ExoT of the T3SS of P. aeruginosa K strain (PAK). The type three secretion system (T3SS) is a major virulence system of Pseudomonas aeruginosa (P. aeruginosa). The effector protein Exotoxin S (ExoS) produced by P. aeruginosa is secreted into the host cells via the T3SS. For the purpose of screening the inhibitors with regard to ExoS secretion, we developed the sandwich-type enzyme-linked immunosorbent assay (ELISA) system. PAK clinical strains induce proinflammatory cytokine production through the T3SS, and this involves NF-κB activation in pneumonia mouse models. We tried to confirm the role of the NF-κB transcription factor in ExoS- and ExoT-induced pneumonia mouse models. pro-inflammatory cytokines induction in response to ExoS and ExoT infection relied on NF-κB activation. Our findings highlight the roles of natural poduct in inhibiting proinflammatory cytokine expression during ExoS and ExoT exposure in PAK infections, paving the way for a novel therapeutic approach for the treatment of pulmonary infections.

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IL-12 Regulates B7-H1 Expression in Ovarian Cancer-associated Macrophages by Effects on NF-κB Signalling

  • Xiong, Hai-Yu;Ma, Ting-Ting;Wu, Bi-Tao;Lin, Yan;Tu, Zhi-Guang
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.14
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    • pp.5767-5772
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    • 2014
  • Background and Aim: B7-H1, a co-inhibitory molecule of the B7 family, is found aberrantly expressed in ovarian cancer cells and infiltrating macrophage/dendritic-like cells, and plays a critical role in immune evasion by ovarian cancer. IL-12, an inducer of Th1 cell development, exerts immunomodulatory effects on ovarian cancer. However, whether IL-12 regulates B7-H1 expression in human ovarian cancer associated-macrophages has not been clarified. Therefore, we investigated the effects of IL-12 on the expression of B7-H1 in ovarian cancer-associated macrophages and possible mechanisms. Methods: PMA induced THP-1-derived macrophages or human monocyte-derived macrophages were treated with recombinant IL-12 (rIL-12) or infected with adenovirus carrying human IL-12 gene (Ad-IL-12-GFP) for 24 h, then cocultured with the SKOV3 ovarian cancer cell line for another 24 h. Macrophages were collected for real-time PCR and Western blot to detect the expression of B7-H1, and activation of the NF-${\kappa}B$ signaling pathway. Moreover, supernatants were collected to assay for IL-12, IFN-${\gamma}$ and IL-10 by ELISA. In addition, monocyte-derived macrophages treated with IFN-${\gamma}$ were cocultured with SKOV3 and determined for the expression of B7-H1. Furthermore, the expression of B7-H1 in monocyte-derived macrophages was also evaluated after blocking NF-${\kappa}B$ signaling. Results: The expression of B7-H1 was significantly upregulated in monocyte-derived macrophages treated with rIL-12 or Ad-IL-12-GFP compared with the control groups (p<0.05), accompanied by a remarkable upregulation of IFN-${\gamma}$ (p<0.05), a marked downregulation of IL-10 (p<0.05) and activation of NF-${\kappa}B$ signaling. However, the upregulation of B7-H1 was inhibited by blocking the NF-${\kappa}B$ signaling pathway (p<0.05). Expression of B7-H1 was also increased (p<0.05) in monocyte-derived macrophages treated with IFN-${\gamma}$ and cocultured with SKOV3. By contrast, the expression of B7-H1 in THP-1-derived macrophages was significantly decreased when treated in the same way as monocyte-derived macrophages (p<0.05), and IL-10 was also significantly decreased but IFN-${\gamma}$ was almost absent. Conclusions: IL-12 upregulates the expression of B7-H1 in monocyte-derived macrophages, which is possible though inducing the secretion of IFN-${\gamma}$ and further activating the NF-${\kappa}B$ signal pathway. However, IL-12 downregulates the expression of B7-H1 in THP-1-derived macrophages, associated with a lack of IFN-${\gamma}$ and inhibition of expression of IL-10.

Inhibition of LPS-induced Inflammatory Biomarkers by Fraction of Citrus hassaku pericarp through Suppression of NF-${\kappa}B$ Activation in RAW264.7 Cells (재래감귤 팔삭의 과피 추출물이 LPS로 활성화 된 RAW264.7 대식세포에서 염증매개물질 억제에 미치는 효과)

  • Kim, Chul-Won;Kim, Sung-Moo;Jeong, Seung-Weon;K., So-Mi Cho;Ahn, Kwang-Seok
    • Journal of Korean Traditional Oncology
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    • v.16 no.2
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    • pp.25-34
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    • 2011
  • Objectives : Citrus is the fruit that is readily available around us. Therefore, we investigated the anti-inflammatory effects of fraction isolated from the Citrus hassaku pericarp in RAW264.7 macrophage cells. Methods : The effects of fraction from Citrus hassaku pericarp on cell viability on RAW264.7 cells were measured by the MTT assay. The mRNA levels of iNOS and COX-2, its protein level by fraction of Citrus hassaku pericarp treatment in RAW264.7 macrophage cells were investigated by RT-PCR and immunoblots. Nitrite accumulation in the culture was measured colorimetrically by the Griess reaction using a Griess reagent. The amount of IL-6 and TNF-${\alpha}$ production was determined using an enzyme-linked immunosorbent assay (ELISA) kit. Results : The results indicated that the fraction of Citrus hassaku pericarp concentration highly suppressed lipopolysaccharide (LPS)-induced nitric oxide (NO) and IL-6 productions without a cytotoxic effect on RAW264.7 cells. fraction of Citrus hassaku pericarp inhibited the expressions of LPS-induced iNOS and COX-2 protein and their mRNA in a dose-dependent manner. Particularly, fraction of Citrus hassaku pericarp suppressed the level of nuclear factor-${\kappa}B$ (NF-${\kappa}B$) activity, which was linked with the suppression of LPS-induced phosphorylation of p65 at serine 276 and p65 translocation into nuclei, but not MAPK signaling. In addition, treatment with fraction of Citrus hassaku pericarp inhibited the production of IL-6 and TNF-${\alpha}$ in LPS-stimulated RAW264.7 cells. Conclusion : Our results indicate that fraction of Citrus hassaku pericarp potentially inhibits the biomarkers related to inflammation through the blocking of NF-${\kappa}B$ p65 activation, and it may be a potential therapeutic candidate for the treatment of inflammatory diseases.

Anti-Inflammatory Effects of Annona muricata Leaf Ethanol Extracts (그라비올라(Annona muricata) 잎 에탄올 추출물의 항염증 효과)

  • Cho, Eun-Ji;Lee, Joeng Hee;Sung, Nak-Yun;Byun, Eui-Hong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.6
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    • pp.681-687
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    • 2017
  • This study was focused on the anti-inflammatory activities of Annona muricata leaf ethanol extracts (AME). Inflammation of macrophages was induced by lipopolysaccharide (LPS) treatment, and various inflammation-mediated factors [cytokines and nitric oxide (NO)] were measured. AME treatment significantly reduced LPS-induced NO, cytokine levels [interleukin (IL)-6, tumor necrosis $factor-{\alpha}$ and $IL-1{\beta}$], and expression of inducible NO synthase and cyclooxygenase-2 in a dose-dependent manner. Mechanical studies showed that AME treatment inhibited activation of mitogen-activated protein kinase and nuclear factor $(NF)-{\kappa}B$ in macrophages treated with LPS. From these results, AME treatment strongly inhibits LPS-induced inflammation through inhibition of $NF-{\kappa}B$ activation, suggesting AME could be a potential candidate for treatment of inflammatory disease as a nutraceutical drug.