• Development and Reproduction
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• v.15 no.1
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• pp.25-30
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• 2011

Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self renewal requires many factors such as Oct4, Sox2, FoxD3, and Nanog. NF-${\kappa}B$ is a transcription factor involved in many biological activities. Expression and activity of NF-${\kappa}B$ increase upon differentiation of ES cells. Reportedly, Nanog protein directly binds to NF-${\kappa}B$ protein and inhibits its activity in ES cells. Here, we found a potential binding site of NF-${\kappa}B$ in the human Nanog promoter and postulated that NF-${\kappa}B$ protein may regulate expression of the Nanog gene. We used human embryonic carcinoma (EC) cells as a model system of ES cells and confirmed decrease of Nanog and increase of NF-${\kappa}B$ upon differentiation induced by retinoic acid. Although deletion analysis on the DNA fragment including NF-${\kappa}B$ binding site suggested involvement of NF-${\kappa}B$ in the negative regulation of the promoter, site-directed mutation of NF-${\kappa}B$ binding site had no effect on the Nanog promoter activity. Furthermore, no direct association of NF-${\kappa}B$ with the Nanog promoter was detected during differentiation. Therefore, we conclude that NF-${\kappa}B$ protein may not be involved in transcriptional regulation of Nanog gene expression in EC cells and possibly in ES cells.

• Natural Product Sciences
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• v.20 no.4
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• pp.227-231
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• 2014

Cimicifuga heracleifolia extract (CHE) was investigated for its effects on the release of nitric oxide (NO) and at the level of inducible nitric oxide synthase (iNOS) gene expression in mouse macrophages. We found that C. heracleifolia elicited a dose-dependent increase in NO production and the level of iNOS mRNA. Since, iNOS transcription has been shown to be under the control of the transcription factor $NF-{\kappa}B$, the effects of CHE on $NF-{\kappa}B$ activation were examined. Transient expression assays with $NF-{\kappa}B$ binding sites linked to the luciferase gene revealed that the increased level of iNOS mRNA, induced by CHE, was mediated by the $NF-{\kappa}B$ transcription factor complex. By using DNA fragments containing the $NF-{\kappa}B$ binding sequence, CHE was shown to activate the protein/DNA binding of $NF-{\kappa}B$ to its cognate site, as measured by electrophoretic mobility shift assay. These results demonstrate that C. heracleifolia stimulates NO production and is able to up-regulate iNOS expression through $NF-{\kappa}B$ transactivation.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.64-68
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• 2013

Previous studies have shown that lactic acid bacteria can inhibit inflammatory responses, but the mechanisms are very little known. In this study, transaction and expression of three proinflammatory factors, iNOS, PTGS-2, and IL8, which are closely related to the inflammatory response, were investigated by luciferase reporter assay and RTPCR in HT-29 cells treated by Lactobacillus acidophilus. The results showed that the live L. acidophilus sharply down-regulated the transcription of these three genes. Because there was a NF-${\kappa}B$ binding site located at -265 bp, -225 bp, and -95 bp upstream of the iNOS, PTGS-2, and IL8 promoters, respectively, we further addressed the effects of NF-${\kappa}B$ on transaction of the three promoters by cotransfection. As was expected, NF-${\kappa}Bs$ remarkably upregulated the activity of the reporter gene and, no effect of NF-${\kappa}B$s on IL-8 promoter transaction was found after NF-${\kappa}B$ binding site mutation of the IL8 promoter in HT-29 cells. In conclusion, the live L. acidophilus decreased the transcriptional activity of NF-${\kappa}B$ and, in turn, inhibited the transaction of NF-${\kappa}B$ on the three proinflammatory factors mentioned above.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.6
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• pp.353-358
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• 2010

This study demonstrates the ability of magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, to inhibit LPS-induced expression of iNOS gene and activation of NF-${\kappa}B$/Rel in RAW 264.7 cells. Immunohisto-chemical staining of iNOS and Western blot analysis showed magnolol to inhibit iNOS gene expression. Reporter gene assay and electrophoretic mobility shift assay showed that magnolol inhibited NF-${\kappa}B$/Rel transcriptional activation and DNA binding, respectively. Since p38 is important in the regulation of iNOS gene expression, we investigated the possibility that magnolol to target p38 for its anti-inflammatory effects. A molecular modeling study proposed a binding position for magnolol that targets the ATP binding site of p38 kinase (3GC7). Direct interaction of magnolol and p38 was further confirmed by pull down assay using magnolol conjugated to Sepharose 4B beads. The specific p38 inhibitor SB203580 abrogated the LPS-induced NF-${\kappa}B$/Rel activation, whereas the selective MEK-1 inhibitor PD98059 did not affect the NF-${\kappa}B$/Rel. Collectively, the results of the series of experiments indicate that magnolol inhibits iNOS gene expression by blocking NF-${\kappa}B$/Rel and p38 kinase signaling.

• BMB Reports
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• v.40 no.1
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• pp.88-94
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• 2007

Matrix metalloproteinase-9 (MMP-9) plays a pivotal role in the turnover of extracellular matrix (ECM) and in the migration of normal and tumor cells in response to normal physiologic and numerous pathologic conditions. Here, we show that the transcription of the MMP-9 gene is induced by lipopolysaccharide (LPS) stimulation in cells of a macrophage lineage (RAW 264.7 cells). We provide evidence that the NF-$\kappa$B binding site of the MMP-9 gene contributes to its expression in the LPS-signaling pathway, since mutation of NF-$\kappa$B binding site of MMP-9 promoter leads to a dramatic reduction in MMP-9 promoter activation. In addition, the degradation of l$\kappa$B$\alpha$;, and the presences of myeloid differentiation protein (MyD88) and tumor necrosis factor receptor-associated kinase 6 (TRAF6) were found to be required for LPS-activated MMP-9 expression. Chromatin immunoprecipitation (ChIP) assays showed that functional interaction between NF-$\kappa$B and the MMP-9 promoter element is necessary for LPS-activated MMP-9 induction in RAW 264.7 cells. In conclusion, our observations demonstrate that NF-$\kappa$B contributes to LPS-induced MMP-9 gene expression in a mouse macrophage cell line.

• Archives of Pharmacal Research
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• v.28 no.3
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• pp.274-279
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• 2005

Pharmacological inhibition of interleukin-12 (IL-12) production may be a therapeutic strategy for preventing the development and progression of disease in experimental models of autoimmunity. In this study, the effects of myricetin, a naturally occurring flavonoid present in fruits, vegetables and medicinal herbs, on the production of IL-12 were investigated in mouse macrophages stimulated with lipopolysaccharide (LPS). Myricetin significantly inhibited the LPS­induced IL-12 production from both primary macrophages and the RAW264.7 monocytic cell-line in a dose-dependent manner. The effect of myricetin on IL-12 gene promoter activation was analyzed by transfecting RAW264.7 cells with IL-12 gene promoter/luciferase constructs. The repressive effect was mapped to a region in the IL-12 gene promoter containing a binding site for NF-${\kappa}B$. Furthermore, activation of macrophages by LPS resulted in markedly enhanced binding activity to the NF-${\kappa}B$ site, which significantly decreased upon addition of myricetin, indicating that myricetin inhibited IL-12 production in LPS-activated macrophages via the down­regulation of NF-KB binding activity.

• The Journal of Korean Medicine
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• v.23 no.1
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• pp.50-60
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• 2002

Objectives: Sunghyangjunggisan (SHJS) is a commonly prescribed drug with a wide neuropharmacological spectrum. The water extracts of SHJS were found to be protective against neurotoxicity elicited by deprivation of serum and glucose. Methods: The morphological examination and Hoechst staining of nucleus also clearly showed that the extracts attenuated the cell shrinkage, membrane blebbing, representing typical neuronal apoptotic phenomena and nucleosome-sized fragmentation under the microscope in PC 12 rat pheochromocytoma cells. Results: Activation of protein kinase A (PKA) with dibutyl-cAMP and forskolin also protected during glucose deprivation, although it was not additive with the effect provided by phorbol ester. Interestingly, treatment with the protein kinase A inhibitor, KT5720, was not neuroprotective in the presence of SHJS. Electrophoretic mobility shift assays were used to characterize the neuroprotective binding of nuclear proteins to consensus sequences for AP-l, nuclear factor kappa B ($NF-{\kappa}B$) after glucose deprivation. When PC 12 cells are induced to undergo apoptosis by serum deprivation, AP-l and $NF-{\kappa}B$ DNA binding activity transiently increases to a slight degree. This stimulation is blocked by the water extracts of SHJS. The site of action of the drugs appeared to involve specific inhibition of AP-1 and nuclear factor kB binding activity. Conclusions: Taken together, these results suggested the possibility that the extracts of SHJS might provide a neurotrophic-like activity in PC 12 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.1
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• pp.55-63
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• 2001

In macrophages, lipopolysaccharide (LPS) alone or in combination with $interferon-{\gamma}\;(IFN-{\gamma})$ has been shown to release a nitric oxide (NO) through the increase of the transcription of the inducible nitric oxide synthase (iNOS) gene. To investigate the exact intracellular signaling pathway of the regulation of iNOS gene transcription by LPS plus $IFN-{\gamma},$ the effects of protein tyrosine kinase (PTK) inhibitor and protein kinase C (PKC) inhibitors on NO production, iNOS mRNA expression, nuclear $factor-_{\kappa}B\;(NF-_{\kappa}B)$ binding activity and the promoter activity of iNOS gene containing two $NF-_{\kappa}B$ sites have been examined in a mouse macrophage RAW 264.7 cells. LPS or $IFN-{\gamma}$ stimulated NO production, and their effect was enhanced synergistically by mixture of LPS and $IFN-{\gamma}.$ The PTK inhibitor such as tyrphostin reduced LPS plus $IFN-{\gamma}-induced$ NO production, iNOS mRNA expression and $NF-_{\kappa}B$ binding activity. In contrast, PKC inhibitors such as H-7, Ro-318220 and staurosporine did not show any effect on them. In addition, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that tyrphostin inhibited the iNOS promoter activity through the $NF-_{\kappa}B$ binding site, whereas PKC inhibitors did not. Taken together, these suggest that PTK, but not PKC pathway, is involved in the regulation of the iNOS gene transcription through the $NF-_{\kappa}B$ sites of iNOS promoter in RAW 264.7 macrophages by LPS plus $IFN-{\gamma}$.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.208-213
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• 2018

Activation of nuclear factor kappa B ($NF{\kappa}B$) leads to the inflammatory process. During this $NF{\kappa}B$-dependent inflammation process, inducible nitric oxide synthase (iNOS) are expressed in the inflammatory cells. Our previous data indicated that a specific septapeptide (GVAWWMY) from the soybean extract fermented by Bacillus licheniformis B1 inhibited iNOS mRNA expression and NO production in cultured macrophage cells. Our further experiments revealed that treatment of same septapeptide resulted in inhibition of LPS-induced $NF{\kappa}B$ activation by reversing degradation of $I{\kappa}B{\alpha}$, an inhibitory protein for $NF{\kappa}B$. The molecular docking indicated that the septapeptide binds to $I{\kappa}B$ kinase ${\beta}$ ($IKK{\beta}$), and thus it can inhibit phosphorylation of $I{\kappa}B{\alpha}$. Supporting this, the binding site for the septapeptide has the highest affinity (-8.7 kcal/mol) and the site was located at the kinase domain (KD) of $IKK{\beta}$, which can significantly affect the kinase activity of $IKK{\beta}$.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.6
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• pp.521-527
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• 2001

Diclofenac, a phenylacetic acid derivative, is a widely used non-steroidal anti-inflammatory drug (NSAID) to provide effective relief of inflammation and pain. Nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been implicated as a mediator of inflammation. We examined the inhibitory effects of diclofenac on the induction of iNOS in RAW 264.7 macrophages which were activated with lipopolysaccharide (LPS) plus interferon-gamma $(IFN-{\gamma}).$ Treatment of RAW 264.7 cells with diclofenac and other NSAIDs (aspirin and indomethacin) significantly inhibited NO production and iNOS protein expression induced by LPS plus $IFN-{\gamma}.$ Also, diclofenac but not aspirin and indomethacin, inhibited iNOS mRNA expression and nuclear factor-kappa B $(NF-{\kappa}B)$ binding activity concentration-dependently. Furthermore, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that only diclofenac inhibited the iNOS promoter activity induced by LPS plus $IFN-{\gamma}$ through the $NF-{\kappa}B$ sites of iNOS promoter. Taken together, these suggest that diclofenac may exert its anti-inflammatory effect by inhibiting iNOS gene expression at the transcriptional level through suppression of $NF-{\kappa}B$ activation.