• KSBB Journal
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• v.28 no.1
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• pp.7-12
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• 2013

Thromboxane $A_2$ ($TXA_2$) is one of major proinflammatory mediators, plays an important role in the development of vascular inflammatory diseases. $TXA_2$ acting through the thromboxane receptor regulates multiple pathways and genes in a variety of cells. In this study, we report that the activation of thromboxane receptor with U46619 increases the interleukin-8 (IL-8) mRNA in vascular endothelial cells. We also demonstrated that U46619 produces the activations of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK), which is required for endothelial IL-8 production. And U46619 enhanced mRNA stability of IL-8 transcripts in endothelial cells. Moreover, inhibition of ERK1/2 or p38MAPK reduced monocyte adhesion to aortic endothelium stimulated by U46619. Therefore, these results suggest that activation of thromboxane receptor promotes the expression of IL-8 via ERK1/2 and p38MAPK activation in endothelial cells.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.35 no.1
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• pp.1-10
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• 2022

Objectives : This study was conducted to confirm the anti-inflammatory effects of Aster glehni Water extracts. Methods : In this study, MTT assay was performed to detect cell viability. To evaluate the anti-inflammatory effects of Aster glehni Water extracts, we examined NO production in LPS-induced macrophages. Expressions of iNOS, COX-2, ERK, p38, JNK were also investigated by using western blot assay. Results : Aster glehni Water extracts have no cytotoxicity at 15.625-1,000㎍/㎖ in RAW 264.7 cells. Aster glehni Extracts inhibited the NO production in a dose-dependent manner in RAW 264.7 cells treated with LPS. Pretreated 250, 500, 1,000㎍/㎖ of Aster glehni water extracts had significantly suppressed expression levels of iNOS, COX-2, p-ERK, p-p38, p-JNK. Conclusions : These results suggest that Aster glehni Water extracts have anti-inflammatory effects and can be used for various inflammatory skin diseases.

• Molecules and Cells
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• v.38 no.3
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• pp.279-284
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• 2015

Obatoclax, a pan-Bcl2 inhibitor, shows antitumor activities in various solid malignancies. Bcl2-deficient mice have shown the importance of Bcl2 in osteoclasts, as the bone mass of the mice was increased by the induced apoptosis of osteoclasts. Despite the importance of Bcl2, the effects of obatoclax on the proliferation and differentiation of osteoclast precursors have not been studied extensively. Here, we describe the anti-proliferative effects of obatoclax on osteoclast precursors and its negative role on fusion of the cells. Stimulation with low doses of obatoclax significantly suppressed the proliferation of osteoclast precursors in a dose-dependent manner while the apoptosis was markedly increased. Its stimulation was sufficient to block the activation of ERK MAP kinase by RANKL. The same was true when PD98059, an ERK inhibitor, was administered to osteoclast precursors. The activation of JNK1/2 and p38 MAP kinase, necessary for osteoclast differentiation, by RANKL was not affected by obatoclax. Interestingly, whereas the number of TRAP-positive mononuclear cells was increased by both obatoclax and PD98059, fused, multinucleated cells larger than $100{\pm}m$ in diameter containing more than 20 nuclei were completely reduced. Consistently, obatoclax failed to regulate the expression of osteoclast marker genes, including c-Fos, TRAP, RANK and CtsK. Instead, the expression of DC-STAMP and Atp6v0d2, genes that regulate osteoclast fusion, by RANKL was significantly abrogated by both obatoclax and PD98059. Taken together, these results suggest that obatoclax down-regulates the proliferation and fusion of osteoclast precursors through the inhibition of the ERK1/2 MAP kinase pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.4
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• pp.187-194
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• 2004

Middle cerebral artery occlusion (MCAO) results in cell death by activation of complex signal pathways for cell death and survival. Hypothermia is a robust neuroprotectant, and its effect has often been attributed to various mechanisms, but it is not yet clear. Upstream from the cell death promoters and executioners are several enzymes that may activate several transcription factors involved in cell death and survival. In this study, we immunohistochemically examined the phosphorylation of mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 kinase during early period of the ischemic injury, following 2 hours (h) of transient MCAO. Increased phosphorylation of ERK and p38 was observed in the vessels at 3 h, neuron-like cells at 6 and 12 h and glia-like cells at 12 h. Activation of JNK was not remarkable, and a few cells showed active JNK following ischemia. Phosphorylation of Elk-1, a transcription factor, was reduced by ischemic insult. Hypothermia attenuated the activation of ERK, p38 and JNK, and inhibited reduction of Elk-1. These data suggest that signals via different MAPK family members converge on the cell damage process and hypothermia protects the brain by interfering with these pathways.

• Biomolecules & Therapeutics
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• v.19 no.4
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• pp.460-465
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• 2011

The present study was undertaken to investigate the influence of quercetin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Quercetin at a low concentration (0.01-0.03 mM) directly and more significantly relaxed fluoride or thromboxane $A_2$-induced vascular contraction than phorbol ester-induced contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, quercetin more significantly inhibited thromboxane $A_2$-induced increases in pMYPT1 levels than phorbol ester-induced increases. It also more significantly inhibited thromboxane $A_2$-induced increases in pMYPT1 levels than pERK1/2 levels suggesting the mechanism involving the primarily inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1. This study provides evidence regarding the mechanism underlying the relaxation effect of quercetin on agonist-induced vascular contraction regardless of endothelial function.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.35 no.2
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• pp.1-12
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• 2022

Objectives : This study was conducted to verify the anti-inflammatory effects of Aster glehni water extracts in HaCaT keratinocytes. Methods : In this study, cell viability was confirmed by MTT assay. Production of TNF-α and IL-6 was determined by ELISA. mRNA expression of TARC and MDC were measusred by qRT-PCR. Also, expressions of p-JNK, JNK, p-ERK, ERK, p-p38, and p-38 were investigated by using western blot assay. Results : Aster glehni water extracts were not shown any significant cytotoxicity at 15.625-500㎍/㎖ in HaCaT keratinocytes. Aster glehni extracts inhibited the TNF-α and IL-6 production in HaCaT keratinocytes treated with TNF-α and IFN-γ. Also, expression of TARC, MDC, p-ERK, and p-STAT1 was decreased. Conclusions : These results suggest that Aster glehni water extracts have anti-inflammatory effects in HaCaT keratinocytes and can be applied to the development of anti-inflammatory treatment substances.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.7
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• pp.896-902
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• 2017

In this study, we investigated citrus Kombucha (CK) produced by three different bacteria strains (Gluconacetobacter xylinus, Gluconacetobacter medellinensis, and Gluconobacter oxydans; named as CK-MOX) identified from traditional Kombucha. During fermentation, the pH level of CK-MOX was gradually reduced, and total acidity slightly increased. Antioxidant activity, measured by DPPH, ABTS, and oxygen radical absorbance capacity assays, markedly increased after fermentation. Moreover, fermented CK-MOX (Day15) exhibited anti-proliferative and anti-migratory activities against EJ human bladder carcinoma cells. Western immunoblot assays showed that treatment with CK-MOX significantly up-regulated phospho-extracellular signaling kinase (ERK) levels. To distinguish whether or not up-regulation of phospho-ERK is the cause or effect, we investigated the viability of EJ cells in the presence of U0126, a mitogen activated protein kinase/ERK kinase 1/2 inhibitor. Pre-treatment with U0126 rescued cells from CK-MOX-induced cell death, which indicates phospho-ERK may be a key regulator in the mechanism of CK-MOX-induced apoptosis of EJ bladder cancer cells. In conclusion, CK-MOX, fermented by a defined composition of bacterial starters, shows antioxidant capacity and anti-cancer activity against EJ bladder cancer cells.

• Journal of Life Science
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• v.19 no.10
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• pp.1438-1443
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• 2009

Renal fibrosis is a final common manifestation of every type of chronic kidney disease. Plasminogen activator inhibitor (PAI)-1 is induced by lipopolysaccharide (LPS) and is known to play an essential role in the progress of renal fibrosis. In this paper, we found that an isoprenoid antibiotic, ascofuranone (AF), suppresses expression of profibrotic factors, PAI-1 and promoter activity of PAI-1 induced by LPS in rat kidney fibroblast cells. We therefore investigated signaling pathway mediated inhibitory effects of LPS-induced PAI-1 by AF in rNRK-49F cells. PAI-1 expression is suppressed by treatment with kinase inhibitors for MEK-1/2, as it isin inhibition of PAI-1 expression by AF, and AF inhibits phosphorylation of ERK-1/2. This study suggest that AF suppresses expression of PAI-1 through the inhibition of an ERK-1/2-dependent signal transduction pathway. The data indicates the possibility that AF can be used to prevent the development and progression of renal fibrosis.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.56-56
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• 2021

Nypa fruticans Wurmb is a mangrove plant belonging to Araceae family. N. fruticans is typically found in Southeast Asia, and in some parts of Queensland, Australia. N. fruticans has phytochemicals, phenolics, and flavonoids. In this study, we investigated the anti-inflammatory effects of the ethyl acetate fraction of N. fruticans (ENF) on the production and expression of cytokines and inflammatory mediators through the major signal transduction pathways. ENF attenuated the level of cytokines in a dose-dependent manner and decreased the production of nitric oxide (NO). ENF decreased the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) via alleviating transcription of nuclear factor-kappa B (NF-κB) by an inhibitor of nuclear factor-kappa B (IκB) degradation. Furthermore, mitogen-activated protein kinase (MAPK) signaling pathways (ERK1/2, JNK1/2, and p38) are known to be involved in the inflammatory response. Phosphorylations of ERK1/2, JNK1/2, and p38 were significantly decreased compared with the ENF-untreated control. Conclusively, ENF was related to alleviating various pro-inflammatory mediators through IκB/NF-κB and MAPK signaling pathways, including p65 translocation to the nucleus.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.4
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• pp.199-205
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• 2006

The functional expression of potassium $(K^+)$ channels has electrophysiologically been studied in bone cells from several species, however, their identity and regulation of gene expressions in bone cells are not well known. In the present study, to investigate how $K^+$ channel expressions are regulated by estrogen, we measured changes of transcript levels of various $Ca^{2+}$-activated ($K_{Ca}$) and ATP-sensitive $K^+$ channels in rat osteoblastic ROS 17/2.8 cells after treatment with estrogen. Application of 17${\beta}$-estradiol $(E_2)$ for 24 h and 48 h increased mRNA and protein expressions of inwardly rectifying $K^+$ channel (Kir) 6.2 and type 2 small conductance $K_{Ca}$ channel (SK2), respectively. Combined treatment of cells with 17${\beta}-E_2$ and ICI 182,780, a pure antiestrogen, suppressed 17${\beta}-E_2$-induced alterations of SK2 and Kir6.2 mRNA levels. In addition, treatment of cells with U0126, a specific inhibitor of extracellular receptor kinases (ERK)1/2, and SP600125, a specific inhibitor of c-jun N-terminal kinase (JNK) blocked the enhancing effects of 17${\beta}-E_2$ on SK2 and Kir6.2 protein expressions. On the other hand, blocking of p38 mitogen-activated protein kinase had no effect. Taken together, these results indicate that 17${\beta}-E_2$ modulates SK2 and Kir6.2 expressions through the estrogen receptor, involving ERK1/2 and JNK activations.