• Biomedical Science Letters
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• v.20 no.2
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• pp.56-61
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• 2014

This study attempted to confirm the antioxidative potential of luteolin against tert-butyl hydroperoxide (t-BHP) induced oxidative damage and to investigate its molecular mechanism related to glutathione (GSH)-dependent enzymes in HepG2 cells. Treatment with luteolin resulted in attenuation of t-BHP induced generation of reactive oxygen species (ROS) and oxidative stress-mediated cell death. In addition, accelerated expression of GSH-dependent antioxidative enzymes, glutathione peroxidase (GPx) and glutathione reductase (GR), and heme oxygenase (HO)-1, as well as strengthened GSH content was induced by treatment with luteolin, which was in accordance with increased nuclear translocation of nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), a transcription factor for phase 2 enzymes, in a dose-dependent manner. These results suggest that the cytoprotective potential of luteolin against oxidative damage can be attributed to fortified GSH-mediated antioxidative pathway and HO-1 expression through regulation of Nrf2 in HepG2 cells.

• Tuberculosis and Respiratory Diseases
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• v.75 no.5
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• pp.205-209
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• 2013

Background: We investigated whether prunetin significantly affects tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$)-induced MUC5AC mucin gene expression, production, inhibitory kappa B ($I{\kappa}B$) degradation and nuclear factor kappa B (NF-kB) p65 translocation in human airway epithelial cells. Methods: Confluent NCI-H292 cells were pretreated with prunetin for 30 minutes and then stimulated with TNF-${\alpha}$ for 24 hours or the indicated periods. MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The effect of prunetin on TNF-${\alpha}$-induced degradation of $I{\kappa}B$ and translocation of NF-${\kappa}B$ p65 was investigated by western blot analysis. Results: We found that incubation of NCI-H292 cells with prunetin significantly inhibited mucin production and down-regulated the MUC5AC gene expression induced by TNF-${\alpha}$. Prunetin inhibited TNF-${\alpha}$-induced degradation of $I{\kappa}B$ and translocation of NF-${\kappa}B$ p65. Conclusion: This result suggests that prunetin inhibits the NF-${\kappa}B$ signaling pathway, which may explain its role in the inhibition of MUC5AC mucin gene expression and production regulated by the NF-${\kappa}B$ signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.345-351
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• 2011

High glucose leads to physio/pathological alterations in diabetes patients. We investigated collagen production in human gingival cells that were cultured in high concentrations of glucose. Collagen synthesis and secretion were increased when the cells were exposed to high concentrations of glucose. We examined endoplasmic reticulum (ER) stress response because glucose metabolism is related to ER functional status. An ER stress response including the expression of glucose regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), inositol requiring enzyme alpha (IRE-$1{\alpha}$) and phosphoreukaryotic initiation factor alpha (p-eIF-$2{\alpha}$) was activated in the presence of high glucose. Activating transcription factor 4 (ATF-4), a downstream protein of p-eIF-$2{\alpha}$ as well as a transcription factor for collagen, was also phosphorylated and translocalized into the nucleus. The chemical chaperone 4-PBA inhibited the ER stress response and ATF-4 phosphorylation as well as nuclear translocation. Our results suggest that high concentrations of glucose-induced collagen are linked to ER stress and the associated phosphorylation and nuclear translocation of ATF-4.

• Journal of Periodontal and Implant Science
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• v.48 no.5
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• pp.284-294
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• 2018

Purpose: Epithelial barrier dysfunction is involved in the pathophysiology of periodontitis and oral lichen planus. Estrogens have been shown to enhance the physical barrier function of intestinal and esophageal epithelia, and we aimed to investigate the effect of estradiol (E2) on the regulation of physical barrier and tight junction (TJ) proteins in human oral epithelial cell monolayers. Methods: HOK-16B cell monolayers cultured on transwells were treated with E2, an estrogen receptor (ER) antagonist (ICI 182,780), tumor necrosis factor alpha ($TNF{\alpha}$), or dexamethasone (Dexa), and the transepithelial electrical resistance (TER) was then measured. Cell proliferation was measured by the cell counting kit (CCK)-8 assay. The levels of TJ proteins and nuclear translocation of nuclear factor $(NF)-{\kappa}B$ were examined by confocal microscopy. Results: E2 treatment increased the TER and the levels of junctional adhesion molecule (JAM)-A and zonula occludens (ZO)-1 in a dose-dependent manner, without affecting cell proliferation during barrier formation. Treatment of the tight-junctioned cell monolayers with $TNF{\alpha}$ induced decreases in the TER and the levels of ZO-1 and nuclear translocation of $NF-{\kappa}B$. These $TNF{\alpha}-induced$ changes were inhibited by E2, and this effect was completely reversed by co-treatment with ICI 182,780. Furthermore, E2 and Dexa presented an additive effect on the epithelial barrier function. Conclusions: E2 reinforces the physical barrier of oral epithelial cells through the nuclear ER-dependent upregulation of TJ proteins. The protective effect of E2 on the $TNF{\alpha}-induced$ impairment of the epithelial barrier and its additive effect with Dexa suggest its potential use to treat oral inflammatory diseases involving epithelial barrier dysfunction.

• BMB Reports
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• v.33 no.6
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• pp.525-530
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• 2000

The nerve growth factor (NGF) induces neuronal differentiation and neurite outgrowth of PC12 cells, whereas epidermal growth factors (EGF) stimulate growth and proliferation of the cells. In spite of this difference, NGF-or EGF-treated PC12 cells share various properties in cellular-signaling pathways. These include the activation of the phosphoinositide (PI)-3 kinase, 70 kDa S6 kinase, and in the mitogen-activated protein (MAP) kinase pathway, following the binding of these growth factors to intrinsic receptor tyrosine kinases (RTKs). Therefore, many studies have been attempted to access the critical signaling events in determining the differentiation and proliferation of PC12 cells. In this study, we investigated the cytosolic phospholipase $A_2$ ($cPLA_2$) in neurite behavior in order to identify the differences of signaling pathways between the NGF-induced differentiation and the EGF-induced proliferation of PC12 cells. We have showed here that the $cPLA_2$ was translocated from cytosol to membrane only in NGF-treated cells. We also demonstrated that this translocation is associated with NGF-induced activation of phospholipase $C-{\gamma}(PLC-{\gamma})$, which elevates intracellular $Ca^{2+}$ concentration. These results reveal that the translocation of $cPLA_2$ may be a requisite event in the neuronal differentiation of PC12 cells. Various phospholipase inhibitors were used to confirm the importance of these enzymes in the differentiation of PC12 cells. Neomycin B, a PLC inhibitor, dramatically inhibited the neurite outgrowth, and two distinct $PLA_2$ inhibitors, 4-bromophenacyl bromide (BPB) and arachidonyltrifluoro-methyl ketone ($AACOCF_3$) also suppressed the neurite outgrowth of the cells, as well Taken together, these data indicated that $cPLA_2$ is involved in NGF-induced neuronal differentiation and neurite outgrowth of PC12 cells.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.221-234
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• 2019

Cancer is genetically, metabolically and infectiously induced life threatening disorder showing aggressive growing pattern with invasive tendency. In order to prevent this global menace from jeopardizing human life, enormous studies on carcinogenesis and treatment for chemotherapy resistance have been intensively researched. Hinokitiol (${\beta}$-thujaplicin) extracted from heart wood of cupressaceous is a well-known bioactive compound demonstrating anti-inflammation, anti-bacteria and anti-cancer effects on several cancer types via apoptosis and autophagy. This study proposed that hinokitiol activates transcription factor EB (TFEB) nuclear translocation for autophagy and lysosomal biogenesis regardless of nutrient condition in cancer cells. Mitophagy and ${\beta}$-catenin translocation into the nucleus under treatment of hinokitiol on non-small cell lung cancer (NSCLC) cells and HeLa cells were investigated. Hinokitiol exerted cytotoxicity on HeLa and HCC827 cells; moreover, artificially induced autophagy by overexpression of TFEB granted imperfect sustainability onto HeLa cells. Taken together, hinokitiol is the prominent autophagy inducer and activator of TFEB nuclear translocation. Alternative cancer therapy via autophagy is pros and cons since the autophagy in cancer cells is related to prevention and survival mechanism depending on nutrition. To avoid paradox of autophagy in cancer therapy, fine-tuned regulation and application of hinokitiol in due course for successful suppressing cancer cells are recommended.

• Biomolecules & Therapeutics
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• v.21 no.3
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• pp.216-221
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• 2013

Aromadendrin, a flavonol, has been reported to possess a variety of pharmacological activities such as anti-inflammatory, antioxidant, and anti-diabetic properties. However, the underlying mechanism by which aromadendrin exerts its biological activity has not been extensively demonstrated. The objective of this study is to elucidate the anti-inflammatory mechanism of aromadedrin in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Aromadendrin significantly suppressed LPS-induced excessive production of pro-inflammatory mediators such as nitric oxide (NO) and $PGE_2$. In accordance, aromadendrin attenuated LPS-induced overexpression iNOS and COX-2. In addition, aromadendrin significantly suppressed LPS-induced degradation of $I{\kappa}B$, which sequesters NF-${\kappa}B$ in cytoplasm, consequently inhibiting the nuclear translocation of pro-inflammatory transcription factor NF-${\kappa}B$. To elucidate the underlying signaling mechanism of anti-inflammatory activity of aromadendrin, MAPK signaling pathway was examined. Aromadendrin significantly attenuated LPS-induced activation of JNK, but not ERK and p38, in a concentration-dependent manner. Taken together, the present study clearly demonstrates that aromadendrin exhibits anti-inflammatory activity through the suppression of nuclear translocation of NF-${\kappa}B$ and phosphorylation of JNK in LPS-stimulated RAW 264.7 macrophage cells.

• YAKHAK HOEJI
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• v.58 no.1
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• pp.1-6
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• 2014

We examined whether silibinin and resveratrol affect airway mucin production, degradation of $I{\kappa}B$ and translocation of NF-${\kappa}B$ p65 induced by TNF-${\alpha}$ in NCI-H292 cells. Cells were pretreated with each agent for 30 min and then stimulated with TNF-${\alpha}$ for 24 h or the indicated periods. The two compounds suppressed TNF-${\alpha}$-induced airway mucin production, degradation of $I{\kappa}B$ and translocation of NF-${\kappa}B$ p65. This result suggests that silibinin and resveratrol can regulate the production of mucin induced by TNF-${\alpha}$ through the inactivation of NF-${\kappa}B$ pathway in airway epithelial cells.

• BMB Reports
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• v.42 no.11
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• pp.764-768
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• 2009

The tandem ubiquitin-interacting motif (UIM) domain located at the N-terminus of Receptor Associated Protein 80 (RAP80) plays a crucial role in ionizing radiation (IR)-induced DNA damage response. RAP80 translocates to sites of IR-induced DNA damage through interaction of its UIM domain with ubiquitinated H2A and Lys63-linked polyubiquitin chains. The exact mechanism, however, through which RAP80 associates with Lys63-linked polyubiquitin chains is not clear. Here, we show by in vitro GST-pull down assays that modifying the linker region between the tandem ubiquitin binding domains of RAP80 changes the binding affinity for Lys63-linked polyubiquitin chains and affects translocation to sites of DNA breaks. Based on these findings, we suggest that the length of the linker region between the tandem ubiquitin binding domains of RAP80 may be a key factor in the binding of RAP80 with Lys63-linked polyubiquitin chains as well as in the translocation of RAP80 to DNA break sites.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.2
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• pp.57-68
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• 2010

Objective : This study was performed to evaluate the effect of Lithospermum erythrorhizon extracts on the inflammatory cytokines gene expression by the bacteria of Propionibacterium acnes (P. acnes) which elicits acne in human monocytes, THP-1 cell line. Experiment : Cytotoxicity of Lithospermum erythrorhizon extracts was analyzed by XTT assay. Real time RT-PCR was applied to analyze the cytokines gene expressions of IL-8, MCP-1 and TNF-$\alpha$. Translocation of transcription factor NF-${\kappa}B$ from cytoplasm into nucleus was observed using immunocytochemistry and confocal microscopy. Results : Lithospermum erythrorhizon extracts did not show cytotoxicity as high as in $1,000\;{\mu}g/ml$ of concentration. Transcription levels of inflammatory cytokines, IL-8, MCP-1 and TNF-$\alpha$ were increased by P. acnes in THP-1 and Lithospermum erythrorhizon extracts decreased the upregulated transcription levels. Lithospermum erythrorhizon extracts significantly inhibited the translocation of NF-${\kappa}B$ into nucleus by P. acnes. Conclusion : This study suggests that Lithospermum erythrorhizon extracts have anti-inflammatory effects on P. acnes treated THP-1 as decreasing the mRNA expressions of IL-8, MCP-1 and TNF-$\alpha$. This anti-inflammatory effect of Lithospermum erythrorhizon extracts may be useful in therapeutic treatments for acne vulgaris.