• BMB Reports
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• v.42 no.7
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• pp.421-426
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• 2009

Glucocorticoids regulate multiple physiological processes such as metabolic homeostasis and immune response. Mouse Pon2 (mPon2) acts as an antioxidant to reduce cellular oxidative stress in cells. In this present study, we investigated the transcriptional regulation of mPon2 by glucocorticoids. In the presence of glucocorticoid analogue dexamethasone, the expression of mPon2 mRNA in cells was increased, whereas the expression was inhibited by a transcription inhibitor actinomycin D. Glucocorticoid receptors bound to the putative glucocorticoid response elements located between -593 bp and -575 bp of the mPon2 promoter. Transcriptional activity was completely blocked when the putative element was mutated. Taken together, these results suggest that the expression of the mPon2 gene is directly regulated by glucocorticoid-glucocorticoid receptor complexes.

• 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.

• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.390-399
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• 2014

Chalcones (1,3-diaryl-2-propen-1-ones), a flavonoid subfamily, are widely known for their anti-inflammatory properties. Propenone moiety in chalcones is known to play an important role in generating biological responses by chalcones. In the present study, we synthesized chalcone derivatives structurally modified in propenone moiety and examined inhibitory effect on nitric oxide (NO) production and its potential mechanisms. Among the chalcone derivatives used for this study, TI-I-174 (3-(2-Hydroxyphenyl)-1-(thiophen-3-yl)prop-2-en-1-one) most potently inhibited lipopolysaccharide (LPS)-stimulated nitrite production in RAW 264.7 macrophages. TI-I-174 treatment also markedly inhibited inducible nitric oxide synthase (iNOS) expression. However, TI-I-174 did not significantly affect production of IL-6, cyclooxygenase-2 (COX-2) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), implying that TI-I-174 inhibits production of inflammatory mediators in a selective manner. Treatment of macrophages with TI-I-174 significantly inhibited transcriptional activity of activator protein-1 (AP-1) as determined by luciferase reporter gene assay, whereas nuclear factor-${\kappa}B$ (NF-${\kappa}B$) activity was not affected by TI-I-1744. In addition, TI-I-174 significantly inhibited activation of c-Jun-N-Terminal kinase (JNK) without affecting ERK1/2 and p38MAPK, indicating that down-regulation of iNOS gene expression by TI-I-174 is mainly attributed by blockade of JNK/AP-1 activation. We also demonstrated that TI-I-174 treatment led to an increase in heme oxygenase-1 (HO-1) expression both at mRNA and protein level. Transfection of siRNA targeting HO-1 reversed TI-I-174-mediated inhibition of nitrite production. Taken together, these results indicate that TI-I-174 suppresses NO production in LPS-stimulated RAW 264.7 macrophages via induction of HO-1 and blockade of AP-1 activation.

• Fisheries and Aquatic Sciences
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• v.20 no.7
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• pp.9.1-9.13
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• 2017

Background: Metal-responsive transcription factor-1 (MTF-1) is a key transcriptional regulator playing crucial roles in metal homeostasis and cellular adaptation to diverse oxidative stresses. In order to understand cellular pathways associated with metal regulation and stress responses in Pacific abalone (Haliotis discus hannai), this study was aimed to isolate the genetic determinant of abalone MTF-1 and to examine its expression characteristics under basal and experimentally stimulated conditions. Results: The abalone MTF-1 shared conserved features in zinc-finger DNA binding domain with its orthologs; however, it represented a non-conservative shape in presumed transactivation domain region with the lack of typical motifs for nuclear export signal (NES) and Cys-cluster. Abalone MTF-1 promoter exhibited various transcription factor binding motifs that would be potentially related with metal regulation, stress responses, and development. The highest messenger RNA (mRNA) expression level of MTF-1 was observed in the testes, and MTF-1 transcripts were detected during the entire period of embryonic and early ontogenic developments. Abalone MTF-1 was found to be Cd inducible and highly modulated by heat shock treatment. Conclusion: Abalone MTF-1 possesses a non-consensus structure of activation domains and represents distinct features for its activation mechanism in response to metal overload and heat stress. The activation mechanism of abalone MTF-1 might include both indirect zinc sensing and direct de novo synthesis of transcripts. Taken together, results from this study could be a useful basis for future researches on stress physiology of this abalone species, particularly with regard to heavy metal detoxification and thermal adaptation.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.481-492
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• 2020

The present study aimed to examine the effect of allyl isothiocyanate (AITC) on chronic obstructive pulmonary disease and to investigate whether upregulation of multidrug resistance-associated protein 1 (MRP1) associated with the activation of the PARK7 (DJ-1)/nuclear factor erythroid 2-related factor 2 (Nrf2) axis. Lung function indexes and histopathological changes in mice were assessed by lung function detection and H&E staining. The expression levels of Nrf2, MRP1, heme oxygenase-1 (HO-1), and DJ-1 were determined by immunohistochemistry, Western blotting and reverse transcription-quantitative polymerase chain reaction. Next, the expression of DJ-1 in human bronchial epithelial (16HBE) cells was silenced by siRNA, and the effect of DJ-1 expression level on cigarette smoke extract (CSE)-stimulated protein degradation and AITC-induced protein expression was examined. The expression of DJ-1, Nrf2, HO-1, and MRP1 was significantly decreased in the wild type model group, while the expression of each protein was significantly increased after administration of AITC. Silencing the expression of DJ-1 in 16HBE cells accelerated CSE-induced protein degradation, and significantly attenuated the AITC-induced mRNA and protein expression of Nrf2 and MRP1. The present study describes a novel mechanism by which AITC induces MRP1 expression by protecting against CS/CSE-mediated DJ-1 protein degradation via activation of the DJ-1/Nrf2 axis.

• The Journal of Korean Medicine
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• v.29 no.1
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• pp.47-59
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• 2008

Objective : Anti-inflammatory effects of the extract of Lycii Fructus on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophage cells were investigated. Method : In order to assess the cytotoxic effect of Lycii Fructus on the raw 264.7 macrophages 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay was performed. Reverse transcription-polymerase chain reaction(RT-PCR) analysis of the mRNA levels of tumor necrosis factor-$\alpha$(TNF-$\alpha$) and inducible nitric oxide synthase(iNOS) was performed in order to provide an estimate of the relative level of expression of these genes. The protein level of the inhibitor of nuclear factor-${\kappa}B(I{\kappa}B)$ and nuclear factor-${\kappa}B$(NF-${\kappa}B$) activity was investigated by Western blot assay. NO production was investigated by NO detection. Result : Lycii Fructus suppressed NO production by inhibiting the LPS-induced expressions of iNOS and TNF-$^-\alpha$ mRNA and iNOS protein in RAW 264.7 macrophage cells. Also, Lycii Fructus suppressed activation of NF-${\kappa}B$ in the nucleus. Conclusion : These results show that the extract of Lycii Fructus has anti-inflammatory effect probably by suppressing iNOS expressions through the down-regulation of NF-${\kappa}B$ binding activity.

• Toxicological Research
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• v.17
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• pp.251-256
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• 2001

The expression of phase II detoxifying enzymes is affected by a variety of compounds and the induction of the enzymes plays an essential role in chemoprevention. A variety of phytochemicals such as sulfur-containing chemoprotective agents (SCC) may trigger cellular signals and activate phase II gene expression through ARE activation. see induces glutathione S-transferases. Studies were conducted to investigate the role of mitogen-activated protein (MAP) kinase and phosphatidylinositol 3-kinase (PI3-kinase) in the induction of GST (e.g. rGSTA2) by sec. We also studied the MAP kinase pathway responsible for the GST expression by see and compared that with the pathway activated by oxidative stress as a result of sulfur amino acids deprivation (SAAD). see inhibited phosphorylation of ERK1/2 although the effect of see on JNK and p38 MAP kinase was minimal. Wortmannin and LY294002. PI3-kinase inhibitors. abolished the increases in rGSTA2 mRNA and protein levels by SCC. Deprivation of cystine and methionine caused oxidative stress in H4IIE cells. as evidenced by a decrease in the reduced glutathione and an increase in prooxidant production. Electrophoretic mobility shift assay revealed that the ARE complex consisting of Nrf-1/2 and Maf proteins was activated 12~48 h. The rGSTA2 mRNA and protein levels were increased by SAAD. Activation of ARE and induction of rGSTA2 were both completely inhibited by PI3-kinase inhibitors. Inhibition of p38 MAP kinase by SB203580 prevented the ARE-mediated rGSTA2 induction. The results of this study showed that PI3-kinase might play an essential role in the ARE-mediated rGSTA2 induction by see or SAAD and that the dual MAP kinase pathways were responsible for the enzyme induction.

• Toxicological Research
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• v.23 no.2
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• pp.135-142
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• 2007

Formononetin is an isoflavonoid phytoestrogen found in certain foodstuffs such as soy and red clover. In this study, we examined the action of formononetin with the carcinogen activation pathway mediated through the aryl hydrocarbon receptor (AhR) in MCF-7 breast carcinoma cells. Treating the cells with formononetin alone caused the accumulation of CYP1A1 mRNA as well as elevation in CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity in a dose dependent manner. However, a concomitant treatment with 7,12-dimethylbenz[a]anthracene (DMBA) and formononetin markedly reduced both the DMBA-inducible EROD activity and CYP1A1 mRNA level. Under the same conditions, formononetin inhibited the DMBA-induced AhR transactivation, as shown by reporter gene analysis using a xenobiotic responsive element (XRE). Additionally, formononetin inhibited both DMBA-inducible nuclear localization of the aryl hydrocarbon receptor (AhR) and metabolic activation of DMBA, as measured by the formation of the DMBA-DNA adducts. Furthermore, formononetin competed with the prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), for binding to the AhR in an isolated rat cytosol. These results suggest that formononetin might be considered as a natural ligand to bind on AhR and consequently produces a potent protective effect against DMBA-induced genotoxicity. Therefore, that's the potential to act as a chemopreventive agent that is related to its effect on AhR pathway as antagonist/agonist.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.6
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• pp.491-497
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• 2015

Traumatic brain injury (TBI) is a major cause of mortality and long-term disability, which can decrease quality of life. In spite of numerous studies suggesting that Epigallocatechin-3- gallate (EGCG) has been used as a therapeutic agent for a broad range of disorders, the effect of EGCG on TBI remains unknown. In this study, a weight drop model was established to evaluate the therapeutic potential of EGCG on TBI. Rats were administered with 100 mg/kg EGCG or PBS intraperitoneally. At different times following trauma, rats were sacrificed for analysis. It was found that EGCG (100 mg/kg, i.p.) treatment significantly reduced brain water content and vascular permeability at 12, 24, 48, 72 hour after TBI. Real-time PCR results revealed that EGCG inhibited TBI-induced IL-$1{\beta}$ and TNF-${\alpha}$ mRNA expression. Importantly, CD68 mRNA expression decreasing in the brain suggested that EGCG inhibited microglia activation. Western blotting and immunohistochemistry results showed that administering of EGCG significantly inhibited the levels of aquaporin-4 (AQP4) and glial fibrillary acidic protein (GFAP) expression. TBI-induced oxidative stress was remarkably impaired by EGCG treatment, which elevated the activities of SOD and GSH-PX. Conversely, EGCG significantly reduced the contents of MDA after TBI. In addition, EGCG decreased TBI-induced NADPH oxidase activation through inhibition of $p47^{phox}$ translocation from cytoplasm to plasma membrane. These data demonstrate that EGCG treatment may be an effective therapeutic strategy for TBI and the underlying mechanism involves inhibition of oxidative stress.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.636-642
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• 2007

Background: CpG DNA plays an important role in immune cell function. This study examined whether the temporal control of toll-like receptor (TLR)9 by CpG DNA can regulate the expression of matrix metalloproteinase-9(MMP-9). Methods and materials: Macrophages were cultured in the presence of 10% FBS. For the various MMP genes analysis, RT-PCR and real-time PCR were performed. In addition, zymography assay performed for the MMP activity. The phosphorylation assay did for the ERK1/2 and NF${\kappa}B$ activation, and luciferase promoter assay was for the NF${\kappa}B$ activity. Results: CpG DNA induced the mRNA expression of MMP-2, MMP-9, and MMP-13, but not of MMP-7, MMP-8, and MMP-12, in a time-dependent manner. Especially, the mRNA expression of MMP-9 was strongly induced by CpG DNA using real-time RT-PCR. The TLR9 inhibitor, chloroquine, suppressed CpG DNA-induced MMP-9 expression and its activity. Moreover, CpG DNA induced the phosphorylation of ERK and the inhibition of ERK by U0126 suppressed CpG DNA-induced MMP-9 expression and its activity. CpG DNA stimulated $I{\kappa}B-{\alpha}$ degradation and luciferase activity. In addition, pretreatment of SN-50, the inhibitor of NF${\kappa}B$, strongly blocked the CpG DNA-induced MMP-9 expression and activity. Conclusion: These observations suggest that CpG DNA may play important roles in the activation of macrophages by regulating the production of MMP-9 via the sequential TLR9-ERK-NF${\kappa}B$ signaling pathway.