• Animal cells and systems
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• v.13 no.4
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• pp.391-397
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• 2009

The house dust mite (Dermatophagoides pteronissinus) is an important factor in triggering allergic diseases. The function of eosinophils, particularly in the production of cytokine or chemokine, is critical in understanding the pathogenesis of inflammatory diseases. In this study, we examined whether D. pteronissinus extract (DpE) induces the expression of monocyte chemotactic protein 1 (MCP-1)/CCL2, IL-8/CXCL8, and IL-6 that mediate in the infiltration and activation of immune cells and in its signaling mechanism in the human eosinophilic cell line, EoL-1. DpE increased the mRNA and protein expression of MCP-1, IL-8, and IL-6 in a time- and dose-dependent course in EoL-1 cells. In our experiments using signal-specific inhibitors, we found that the increased expression of MCP-1, IL-8, and IL-6 due to DpE is associated with Src family tyrosine kinase and protein kinase C $\delta$ (PKC $\delta$). In addition, the activation of extracellular signal-regulated kinase (ERK) is required for MCP-1 and IL-8 expression while p38 mitogen-activated protein kinase (MAPK) is involved in IL-6 expression. DpE induced the phosphorylation of ERK and p38 MAPK. PP2, an inhibitor of Src family tyrosine kinase, and rottlerin, an inhibitor of PKC $\delta$, blocked the activation of ERK and p38 MAPK. DpE induces the activation of ERK and p38 MAPK via Src family tyrosine kinase and PKC $\delta$ for MCP-1, IL-8, or IL-6 production. Increased cytokine release due to the house dust mite and the characterization of its signal transduction may be valuable in understanding the eosinophil-related pathogenic mechanism of inflammatory diseases.

• 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.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.589-597
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• 2015

It has been reported that overexpression of MUC5AC induced by excessive inflammation leads to airway obstruction in respiratory diseases such as chronic obstructive pulmonary disease and asthma. 15-Hydroxyeicosatetraenoic acid (15-HETE) has been reported to have anti-inflammatory effects, but the role of 15-HETE in respiratory inflammation has not been determined. Therefore, the aim of this study was to investigate the effects of 15-HETE on MUC5AC expression and related pathways. In this study, phorbol-12-myristate-13-acetate (PMA) was used to stimulate NCI-H292 bronchial epithelial cells in order to examine the effects of 15-HETE. 15-HETE inhibited PMA-induced expression of MUC5AC mRNA and secretion of MUC5AC protein. Moreover, 15-HETE regulated matrix metallopeptidase 9 (MMP-9), mitogen-activated protein kinase kinase (MEK), and extracellular signal-regulated kinase (ERK). In addition, 15-HETE decreased the nuclear translocation of specificity protein-1 (Sp-1) transcription factor and nuclear factor κB (NF-κB). Furthermore, 15-HETE enhanced the transcriptional activity of peroxisome proliferator-activated receptor gamma (PPARγ) as a PPARγ agonist. This activity reduced the phosphorylation of protein kinase B (PΚB/Akt) by increasing the expression of phosphatase and tensin homolog (PTEN). In conclusion, 15-HETE regulated MUC5AC expression via modulating MMP-9, MEK/ERK/Sp-1, and PPARγ/PTEN/Akt signaling pathways in PMA-treated respiratory epithelial cells.

• Journal of Life Science
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• v.28 no.1
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• pp.43-49
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• 2018

Chrysoeriol is a widespread flavone, and it is usually found in alfalfa, which has been used as a traditional medicine to treat dyspepsia, asthma, and urinary system disorders. Recently, analysis has been conducted on the anti-inflammatory activity of chrysoeriol, but information on its antioxidative capacity is limited. In this study, the antioxidative potential of chrysoeriol against oxidative damage and its molecular mechanisms were evaluated by analysis of the cell viability, reactive oxygen species (ROS) formation, and Western blots in the RAW 264.7 cell line. Chrysoeriol significantly scavenged lipopolysaccharide (LPS)-induced intracellular ROS formation in a dose-dependent manner, without any cytotoxicity. Heme oxygenase-1 (HO-1), a phase II enzyme that exerts antioxidative activity, was also potently induced by chrysoeriol treatment, which corresponded to the translocation of nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) into the nucleus. Moreover, mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) were analyzed due to their important role in maintaining cellular redox homeostasis against oxidative stress. As a result, chrysoeriol-induced HO-1 upregulation was mediated by extracellular signal - regulated kinase (ERK), c-Jun $NH_2$-terminal kinase (JNK), and p38 phosphorylation. To identify the antioxidative potential exerted by HO-1, tert-butyl hydroperoxide (t-BHP)-induced oxidative damage was applied and mitigated by chrysoeriol treatment, which was confirmed by the HO-1 selective inhibitor and inducer, respectively. Consequently, chrysoeriol strongly strengthened the HO-1-mediated antioxidative potential through the regulation of the Nrf2/MAPK signaling pathways.

• Journal of Life Science
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• v.33 no.6
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• pp.463-470
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• 2023

Desmarestia tabacoides Okamura is a brown macroalgae that is found worldwide. Although several genera of Desmarestia have been reported as having anti-tumorigenic, anti-melanogenic, and photoprotective properties, the anti-inflammatory activity of D. tabacoides Okamura has not yet been evaluated. In this study, we analyzed the anti-inflammatory mechanisms of D. tabacoides Okamura ethanol extract (DTEE) via the inhibition of nitric oxide (NO) and prostaglandin (PG) E₂ production and the expression of their corresponding enzymes, inducible NO synthase (iNOS), and cyclooxygenase (COX)-2. In addition, their upstream signaling molecules were evaluated by Western blot analysis, such as nuclear factor (NF)-κB, mitogen-activated protein kinase (MAPK), and phosphoinositide-3-kinase (PI3K)/Akt, in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The DTEE treatment significantly inhibited LPS-induced NO and PGE₂ production as well as the expression of their corresponding enzymes, iNOS, and COX-2 without cytotoxicity. The stimulated transcription factor NF-κB and upstream signaling molecules extracellular signal-regulated kinase (ERK), c-Jun NH₂-terminal kinase (JNK), and p38 were attenuated by the DTEE treatment, which was statistically significant, while Akt did not provide any inhibitory effect. Moreover, the DTEE treatment significantly mitigated the LPS-activated adaptor molecules, toll-like receptor 4 (TLR4), and myeloid differentiation primary response 88 (MyD88) in the RAW 264.7 cells. These results suggest that DTEE attenuates TLR4-mediated inflammatory responses by inhibiting NF-κB activation and suppressing MAPK phosphorylation in LPS-stimulated RAW 264.7 cells.

• BMB Reports
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• v.36 no.5
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• pp.468-474
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• 2003

The molecular mechanism of hypoxia-induced apoptosis has not been clearly elucidated. In this study, we investigated the involvement of extracellular signal-regulated protein kinase (ERK 1/2) in hypoxia-induced apoptosis using cobalt chloride in HeLa human cervical cancer cells. The cobalt chloride was used for the induction of hypoxia, and its $IC_{50}$ was $471.4\;{\mu}M$. We demonstrated the DNA fragmentation after incubation with concentrations more than $50\;{\mu}M$ cobalt chloride for 24 h, and also evidenced the morphological changes of the cells undergoing apoptosis with electron microscopy. Next, we examined the signaling pathway of cobalt chloride-induced apoptosis in HeLa cells. ERK1/2 activation occurred 6 and 9 h after treatment with $600\;{\mu}M$ cobalt chloride. Meanwhile, the pretreatment of the MEK 1 inhibitor (PD98059) completely blocked the cobalt chloride-induced ERK 1/2 activation. At the same time, the activated ERK 1/2 translocated into the nucleus and phosphorylated its transcriptional factor, c-Jun. In addition, the pretreatment of PD98059 inhibited the cobalt chloride-induced DNA fragmentation and apoptotic cell death. These results suggest that cobalt chloride is able to induce apoptotic activity in HeLa cells, and its apoptotic mechanism may be associated with signal transduction via ERK 1/2.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.147.3-148
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• 2003

Recently, there have been considerable efforts to search for naturally occurring substances for the intervention of carcinogenesis. Curcumin, a yellow coloring ingredient of turmeric (Curcuma longa L., Zingiberaceae), has been shown to inhibit experimental carcinogenesis and mutagenesis, but molecular mechanisms underlying its chemopreventive activities remain unclear. In the present work, we found that curcumin inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced expression of CPX-2 in female ICR mouse skin when applied topically 30 min prior to TPA as determined by both immunoblot and immunohistochemical analyses. (omitted)

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.339-346
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• 2000

Using murine immortalized microglial cells (BV-2), we examined the regulation of RANTES production stimulated by lipopolysaccharide (LPS), focusing on the role of mitogen-activated protein kinase (MAPK) and nuclear factor $(NF)-{\kappa}B.$ The result showed that RANTES (regulated upon activation of normal T cell expressed and secreted) was induced at the mRNA and protein levels in a dose- and time-dependent manner in response to LPS. From investigations of second messenger pathways involved in regulating the secretion of RANTES, we found that LPS induced phosphorylation of extracellular signal-regulated kinase (Erk), p38 MAPK and c-Jun-N-terminal kinase (JNK), and activated $(NF)-{\kappa}B.$ To determine whether this MAPK phosphorylation is involved in LPS-stimulated RANTES production, we used specific inhibitors for p38 MAPK and Erk, SB 203580 and PD 98059, respectively. LPS-induced RANTES production was reduced approximately 80% at $25\;{\mu}M$ of SB 203580 treatment. But PD 98059 did not affect RANTES production. Pyrrolidine-dithiocarbamate (PDTC), $(NF)-{\kappa}B$ inhibitor, reduced RANTES secretion. These results suggest that LPS-induced RANTES production in microglial cells (BV-2) is mainly mediated by the coordination of p38 MAPK and $(NF)-{\kappa}B$ cascade.

• International Journal of Oral Biology
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• v.44 no.2
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• pp.43-49
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• 2019

Tannic acid (TA) is a water-soluble polyphenol compound found in various herbal plants. We investigated the chemopreventive effects of TA on FaDu hypopharyngeal squamous carcinoma cells. In an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, TA showed dose-dependent cytotoxicity with a half maximal inhibitory concentration (IC50) of 50 ?M. Cell cycle analysis and immunofluorescence imaging demonstrated that under low-dose ($25{\mu}M$) treatment, FaDu cells were arrested in G2/M phase, and as the dose of TA was increased, apoptosis was induced with the increase of cell population at sub-G1 phase. The expressions of various cyclins, including cyclin D1 and cyclin-dependent kinases (CDK-1 and CDK-2), were down-regulated at low doses of TA, whereas apoptotic effectors such as cleaved caspase 3, cleaved caspase 7, and poly (ADP-ribose) polymerase (PARP) were expressed in a dose-dependent manner in Western blotting. In addition, TA-induced apoptosis of FaDu cells might be mediated by the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase pathway, with the upregulation of p-AKT/p-PKB (phosphorylated protein kinase B) and p-ERK. Overall, our data support the hypothesis that TA is a potential candidate agent for the treatment of hypopharyngeal cancer.

• Food Science of Animal Resources
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• v.44 no.4
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• pp.885-898
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• 2024

Ovomucin (OM), which has insoluble fractions is a viscous glycoprotein, found in egg albumin. Enzymatic hydrolysates of OM have water solubility and bioactive properties. This study investigated that the immunostimulatory effects of OM hydrolysates (OMHs) obtained by using various proteolytic enzymes (Alcalase^®, bromelain, α-chymotrypsin, Neutrase^®, pancreatin, papain, Protamax^®, and trypsin) in RAW 264.7 cells. The results showed that OMH prepared with pancreatin (OMPA) produced the highest levels of nitrite oxide in RAW 264.7 cells, through upregulation of inducible nitric oxide synthase mRNA expression. The production of pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin-6 were increased with the cytokines mRNA expression. The effect of OMPA on mitogen-activated protein kinase signaling pathway was increased the phosphorylation of p38, c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase in a concentration-dependent manner. Therefore, OMPA could be used as a potential immune-stimulating agent in the functional food industry.