• Molecular & Cellular Toxicology
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• v.5 no.2
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• pp.120-125
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• 2009

Alaria esculenta is a brown seaweed found in the Arctic. This study investigated the protective effect of A. esculenta extract (AEE) against oxidant-mediated injury and its mode of action in RAW264.7 macrophages. The methyl thiazolyl tetrazolium (MTT) assay showed that $H_2O_2$ treatment reduced cell viability, whereas AEE protected cells from $H_2O_2$-mediated cytotoxicity in a dose-dependent manner. Because heme oxygenase-1 (HO-1) is known to protect cells against oxidative damage, we investigated the effect of AEE on HO-1 gene expression and HO enzyme activity. The protective effect of AEE against $H_2O_2$-induced injury was correlated with increased HO enzyme activity. AEE also induced HO-1 mRNA and protein expression, as determined RT-PCR and Western blotting, respectively. To characterize the mechanisms by which AEE induces HO-1 gene expression, we examined the effect of AEE on the nuclear translocation of NF-E2-related factor-2 (Nrf2) and Akt phosphorylation. AEE treatment activated upstream signaling for HO-1 gene expression, including the nuclear translocation of Nrf2 and Akt phosphorylation. Collectively, these results suggest that AEE has anti-oxidant activity that is mediated, at least in part, via the activation of Nrf2 and Akt and the subsequent induction of HO-1 gene expression.

• Biomedical Science Letters
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• v.9 no.2
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• pp.59-65
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• 2003

When cells are exposed to proteotoxic stresses such as heat shock, amino acid analogs, and heavy metals, they increase the synthesis of the heat shock proteins (HSPs) by activating the heat shock transcription factor 1 (HSF1), whose activity is controlled via multiple steps including homotrimerization, nuclear translocation, DNA binding, and hyperphosphorylation. Under unstressed conditions, the HSF1 activity is repressed through its constitutive phosphorylation by glycogen synthase kinase 3$\beta$ (GSK3$\beta$), extracellular regulated kinase 1/2 (ERK1/2), and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK). However, the protein kinase (s) responsible for HSF1 hyperphosphorylation and activation is not yet identified. In the present study, we observed that profile of p38 mitogen-activated protein kinase (p38MAPK) activation in response to heat shock was very similar to those of HSF1 hyperphosphorylation and nuclear translocation. Therefore, we investigated whether p38MAPK is involved in the heat shock-induced HSF1 activation and HSP expression. Here we show that the p38MAPK inhibitors, SB202190 and SB203580, but not other inhibitors including the MEK1/2 inhibitor PD98059 and the PI3-K inhibitor LY294002 and wortmannin, suppress HSF1 hyperphosphorylation in response to heat shock and L-azetidine 2-carboxylic acid (Azc), but not to heavy metals. Furthermore, heat shock-induced HSF1-DNA binding and HSP72 expression was specifically prevented by the p38MAPK inhibitors, but not by the MEK1/2 inhibitor and the PI3-K inhibitors. These results suggest that SB202190- and SB203580-sensitive p38MAPK may positively regulate HSP gene regulation in response to heat shock and amino acid analogs.

• Biomolecules & Therapeutics
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• v.19 no.4
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• pp.431-437
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• 2011

Aberrant activation of microglia has been reported to cause neuronal damages by releasing a variety of pro-inflammatory cytokines. Besides where microglia become active, damages have been also observed in remote places, which is considered due to the migration of activated microglia. Therefore, an agent that could suppress abnormal activation of microglia and their subsequent migration might be valuable in activated microglia-related brain pathologies. The objective of the present study was to evaluate anti-inflammatory effects of betulinic acid on lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Pretreatment of betulinic acid significantly attenuated LPS-induced NO production and protein expression of iNOS. Betulinic acid also significantly suppressed LPS-induced release and expression of cytokines such as TNF-${\alpha}$ and IL-$1{\beta}$. Furthermore, betulinic acid significantly uppressed LPS-induced MMP-9 expression, which has been suggested to play an important role in the migration of activated microglia. In order to understand the possible mechanism by which betulinic acid suppresses LPS-induced cytokine production and migration of microglia, the role of NF-kB, a major pro-inflammatory transcription factor, was examined. Betulinic acid significantly suppressed LPS-induced degradation of IKB, which retains NF-kB in the cytoplasm. Therefore, nuclear translocation of NF-kB upon LPS stimulation was significantly suppressed with betulinic acid. Taken together, the present study for the first time demonstrates that betulinic acid possesses anti-inflammatory activity through the suppression of nuclear translocation of NF-kB in BV2 microglial cells.

• Molecules and Cells
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• v.44 no.1
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• pp.38-49
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• 2021

Airway mucus secretion is an essential innate immune response for host protection. However, overproduction and hypersecretion of mucus, mainly composed of the gel-forming MUC5AC protein, are significant risk factors for patients with asthma and chronic obstructive pulmonary disease (COPD). The transforming growth factor β (TGFβ) signaling pathway negatively regulates MUC5AC expression; however, the underlying molecular mechanism is not fully understood. Here, we showed that TGFβ significantly reduces the expression of MUC5AC mRNA and its protein in NCI-H292 cells, a human mucoepidermoid carcinoma cell line. This reduced MUC5AC expression was restored by a TGFβ receptor inhibitor (SB431542), but not by the inhibition of NF-κB (BAY11-7082 or Triptolide) or PI3K (LY294002) activities. TGFβ-activated Smad3 dose-dependently bound to MUC5AC promoter. Notably, TGFβ-activated Smad3 recruited HDAC2 and facilitated nuclear translocation of HDAC2, thereby inducing the deacetylation of NF-κB at K310, which is essential for a reduction in NF-κB transcriptional activity. Both TGFβ-induced nuclear translocation of Smad3/HDAC2 and deacetylation of NF-κB at K310 were suppressed by a Smad3 inhibitor (SIS3). These results suggest that the TGFβ-activated Smad3/HDAC2 complex is an essential negative regulator for MUC5AC expression and an epigenetic regulator for NF-κB acetylation. Therefore, these results collectively suggest that modulation of the TGFβ1/Smad3/HDAC2/NF-κB pathway axis can be a promising way to improve lung function as a treatment strategy for asthma and COPD.

• Reproductive and Developmental Biology
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• v.36 no.4
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• pp.237-241
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• 2012

Embryonic genome activation (EGA) is the first major transition that occurs after fertilization, and entails a dramatic reprogramming of gene expression that is essential for continued development. Although it has been suggested that EGA in porcine embryos starts at the four-cell stage, recent evidence indicates that EGA may commence even earlier; however, the molecular details of EGA remain incompletely understood. The RNA polymerase II of eukaryotes transcribes mRNAs and most small nuclear RNAs. The largest subunit of RNA polymerase II can become phosphorylated in the C-terminal domain. The unphosphorylated form of the RNA polymerase II largest subunit C-terminal domain (IIa) plays a role in initiation of transcription, and the phosphorylated form (IIo) is required for transcriptional elongation and mRNA splicing. In the present study, we explored the nuclear translocation, nuclear localization, and phosphorylation dynamics of the RNA polymerase II C-terminal domain in immature pig oocytes, mature oocytes, two-, four-, and eight-cell embryos, and the morula and blastocyst. To this end, we used antibodies specific for the IIa and IIo forms of RNA polymerase II to stain the proteins. Unphosphorylated RNA polymerase II stained strongly in the nuclei of germinal vesicle oocytes, whereas the phosphorylated form of the enzyme was confined to the chromatin of prophase I oocytes. After fertilization, both unphosphorylated and phosphorylated RNA polymerase II began to accumulate in the nuclei of early stage one-cell embryos, and this pattern was maintained through to the blastocyst stage. The results suggest that both porcine oocytes and early embryos are transcriptionally competent, and that transcription of embryonic genes during the first three cell cycles parallels expression of phosphorylated RNA polymerase II.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.6
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• pp.1825-1831
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• 2004

Phellinus linteus is known as a medicinal mushroom, which has the pharmaceutical activity on tumors and inflammatory diseases in traditional Oriental medicine. However, despite extensive pharmacological studies on P. linteus, the liquor of fermentation using mycelium of P. linteus(LFMP) has not been investigated. In the present study, it was examined the effect of the evaporating extract from LFMP(E-LFMP) on the expression of inflammatory proteins and the generation of reactive oxygen species in human hepatocarcinoma HepG2 cells. E-LFMP inhibited acetaldehyde-induced morphological change in HepG2 cells. Also, E-LFMP inhibits expression of inflammatory proteins including cyclooxygenase(COX)-1 and COX-2 through suppressing nuclear translocation of nuclear factor κB(NF-κB) and degradation of inhibitory κBα(IκBα). In addition, E-LFMP inhibits generation of reactive oxygen species(ROS) by hydrogen peroxide(H₂O₂) in HepG2 cells. These results suggest that LFMP has the pharmaceutical, especially anti-inflammatory, activity similar to P. linteus mushroom.

• Biomolecules & Therapeutics
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• v.24 no.4
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• pp.387-394
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• 2016

Sepsis, a serious clinical problem, is characterized by a systemic inflammatory response to infection and leads to organ failure. Toll-like receptor (TLR) signaling is intimately implicated in hyper-inflammatory responses and tissue injury during sepsis. Histone deacetylase (HDAC) inhibitors have been reported to exhibit anti-inflammatory properties. The aim of this study was to investigate the hepatoprotective mechanisms of trichostatin A (TSA), a HDAC inhibitor, associated with TLR signaling pathway during sepsis. The anti-inflammatory properties of TSA were assayed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Polymicrobial sepsis was induced in mice by cecal ligation and puncture (CLP), a clinically relevant model of sepsis. The mice were intraperitoneally received TSA (1, 2 or 5 mg/kg) 30 min before CLP. The serum and liver samples were collected 6 and 24-h after CLP. TSA inhibited the increased production of tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-6 in LPS-stimulated RAW264.7 cells. TSA improved sepsis-induced mortality, attenuated liver injury and decreased serum TNF-${\alpha}$ and IL-6 levels. CLP increased the levels of TLR4, TLR2 and myeloid differentiation primary response protein 88 (MyD88) protein expression and association of MyD88 with TLR4 and TLR2, which were attenuated by TSA. CLP increased nuclear translocation of nuclear factor kappa B and decreased cytosolic inhibitor of kappa B ($I{\kappa}B$) protein expression, which were attenuated by TSA. Moreover, CLP decreased acetylation of $I{\kappa}B$ kinase (IKK) and increased association of IKK with $I{\kappa}B$ and TSA attenuated these alterations. Our findings suggest that TSA attenuates liver injury by inhibiting TLR-mediated inflammatory response during sepsis.

• Biomolecules & Therapeutics
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• v.26 no.6
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• pp.560-567
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• 2018

In the present study, we tried to examine whether resveratrol regulates the expression of matrix metalloproteinases (MMPs) through affecting nuclear factor-kappa B ($NF-{\kappa}B$) in articular chondrocytes. Rabbit articular chondrocytes were cultured in a monolayer, and reverse transcription-polymerase chain reaction (RT-PCR) was used to measure interleukin-${\beta}$ ($IL-1{\beta}$)-induced gene expression of MMP-3, MMP-1, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4), ADAMTS-5 and type II collagen. Effect of resveratrol on $IL-1{\beta}$-induced secretion of MMP-3 was investigated in rabbit articular chondrocytes using western blot analysis. To elucidate the action mechanism of resveratrol, effect of resveratrol on $IL-1{\beta}$-induced $NF-{\kappa}B$ signaling pathway was investigated in SW1353, a human chondrosarcoma cell line, by western blot analysis. The results were as follows: (1) resveratrol inhibited the gene expression of MMP-3, MMP-1, MMP-13, ADAMTS-4, and ADAMTS-5, but increased the gene expression of type II collagen; (2) resveratrol reduced the secretion of MMP-3; (3) resveratrol inhibited $IL-1{\beta}$induced activation (phosphorylation) of inhibitory kappa B kinase (IKK), and thus phosphorylation and degradation of inhibitory kappa $B{\alpha}$ ($I{\kappa}B{\alpha}$); (4) resveratrol inhibited $IL-1{\beta}$-induced phosphorylation and nuclear translocation of $NF-{\kappa}B$ p65. This, in turn, led to the down-regulation of gene expression of MMPs in SW1353 cells. These results suggest that resveratrol can regulate the expression of MMPs through affecting $NF-{\kappa}B$ by directly acting on articular chondrocytes.

• Natural Product Sciences
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• v.10 no.6
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• pp.315-320
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• 2004

Alpha-viniferin was previously isolated as a cyclooxygenase (COX)-2 inhibitor from Carex humilis (Cyperaceae) and is an oligomeric stilbene compound with benzofuran (BF) moieties in its chemical structure. In the present study, a chemically synthetic BF compound, named as 3,3-dimethyl-2,3,4,6,7,8,9,10,11,12,13,14,15,16,17,18-hexadecahydro-1H-benzo[b] cyclopentadeca[d]furan-1-one, was discovered to inhibit bacterial lipo polysaccharide (LPS)-induced prostaglandin $E_2$ $(PGE_2)$ production in macrophages RAW 264.7. The BF compound exhibited a selectively preferred inhibitory effect on COX-2 activity over COX-1 activity. Furthermore, BF compound inhibited LPS-induced COX-2 expression at transcription level. As a down-regulatory mechanism of COX-2 expression shown by BF compound, suppression of nuclear factor $(NF)-{\kappa}B$ activation has been demonstrated. BF compound inhibited LPS-induced $NF-{\kappa}B$ transcriptional activity and nuclear translocation of $NF-{\kappa}B$ p65, in parallel, but did not affect LPS-induced degradation of inhibitory ${\kappa}B{\alpha}$ protein $(I{\kappa}B{\alpha})$. Taken together, anti-inflammatory effect of BF compound on $PGE_2$ production was ascribed by its down-regulatory action on LPS-induced COX-2 synthesis in addition to inhibitory action on enzyme activity of COX-2.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.6
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• pp.671-677
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• 2018

In the present study, we investigated whether tussilagone, a natural product derived from Tussilago farfara, significantly affects the production and gene expression of airway MUC5AC mucin. Confluent NCI-H292 cells were pretreated with tussilagone for 30 min and then stimulated with EGF (epidermal growth factor) or PMA (phorbol 12-myristate 13-acetate) for 24 h or the indicated periods. The MUC5AC mucin gene expression was measured by RT-PCR. Production of MUC5AC mucin protein was measured by ELISA. To elucidate the action mechanism of tussilagone, effect of tussilagone on PMA-induced $NF-{\kappa}B$ signaling pathway was investigated by western blot analysis. Tussilagone significantly inhibited the production of MUC5AC mucin protein and down-regulated the expression of MUC5AC mucin gene, induced by EGF or PMA. Tussilagone inhibited PMA-induced activation (phosphorylation) of inhibitory kappa B kinase (IKK), and thus phosphorylation and degradation of inhibitory kappa Ba ($I{\kappa}B{\alpha}$). Tussilagone inhibited PMA-induced phosphorylation and nuclear translocation of nuclear factor kappa B ($NF-{\kappa}B$) p65. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. These results suggest that tussilagone can regulate the production and gene expression of mucin by acting on airway epithelial cells through regulation of $NF-{\kappa}B$ signaling pathway.