• The Journal of Internal Korean Medicine
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• v.34 no.2
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• pp.204-214
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• 2013

Objectives : This study was designed to investigate the cellular and molecular mechanisms of anti-inflammatory activity of the water extract of Polygala tenuifolia Willd. (Pt-WE). Methods : Using lipopolysaccharide (LPS)-stimulated murine RAW264.7 cells, we examined inflammatory mediators such as nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase (COX)-2 and prostaglandin $E_2$ ($PGE_2$). Also, the inhibitory effect of Pt-WE on the activity of activator protein 1 (AP-1) and upstream signaling molecules was evaluated. To assess the protective effect of Pt-WE on hydrochloride/ethanol (HCl/EtOH)-induced gastric ulcer in mice, we compared Pt-WE (200 mg/kg) with ranitidine (50 mg/kg) treated mice's gastric mucosa, based on gross observations. Results : Pt-WE inhibited LPS-induced production of NO, $PGE_2$ in a dose-dependent manner, without causing cytotoxicity. Pt-WE suppressed AP-1 activation by reducing generations of both c-Jun and c-Fos. In addition, Pt-WE inhibited the p-MKK 4/7 (mitogen-activated protein kinase kinase 4/7) and p-JNK (c-Jun N-terminal kinase) 1 in LPS-stimulated RAW264.7 cells. HCl/EtOH-induced gastric ulcer lesions were inhibited by pre-treatment of Pt-WE based on gross observations. In addition, Pt-WE decreased the phosphorylation level of JNK. Conclusions : These results demonstrate that Pt-WE has anti-inflammatory and gastroprotective effects. Thus, Pt-WE may be used widely in treatment of not only neurodegenerative diseases but also inflammatory diseases.

• International Journal of Oral Biology
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• v.34 no.2
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• pp.115-121
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• 2009

Bone morphogenetic protein (BMP) 2 is a potent osteogenic factor. Although both Smad1/5 and mitogenactivated protein kinases (MAPKs) are activated by BMP2, the hierarchical relationship between them is unclear. In this study, we examined if BMP2-stimulated MAPK activation is regulated by Smad1/5 or vice versa. When C2C12 cells were treated with BMP2, the activation of extracellular signal-regulated kinase (ERK), p38 MAPK and c-Jun-N-terminal kinase was evident within 5 min. The knockdown of both Smad1 and Smad5 by small interfering RNA did not affect the activation of these MAPKs. In addition, neither the overexpression of Smad1 nor Smad5 induced ERK activation. When ERK activation was induced by constitutively active MEK1 expression, the protein level and activation of Smad1 increased. Furthermore, the inhibition of constitutively active BMP receptor type IB-induced ERK activation significantly suppressed Smad1 activation. These results indicate that Smad1/5 activation is not necessary for BMP2-induced MAPK activation and also that ERK positively regulates Smad1 activation.

• Molecular Medicine Reports
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• v.21 no.3
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• pp.1374-1382
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• 2020

Arctigenin is a natural lignan that is found in burdock with anti-viral, -oxidative, -inflammatory and anti-tumor activities. In the current study, the effect of arctigenin on metastatic potential was examined in 4T-1 mouse triple-negative breast cancer cells. The results indicated that arctigenin inhibited cell motility and invasiveness, which was determined using wound healing and transwell invasion assays. Arctigenin suppressed matrix metalloprotease-9 (MMP-9) activity via gelatin zymography, and protein expression of cyclooxygenase-2 (COX-2) and MMP-3. Furthermore, arctigenin attenuated the mRNA expression of metastatic factors, including MMP-9, MMP-3 and COX-2. Based on these results, the effect of arctigenin on the mitogen-activated protein kinase (MAPK)/activating protein-1 (AP-1) signaling pathway was assessed in an attempt to identify the regulatory mechanism responsible for its anti-metastatic effects. Arctigenin was demonstrated to inhibit the phosphorylation of extracellular signal-regulated protein kinase (ERK) and c-Jun N- terminal kinase (JNK), and the nuclear translocations of the AP-1 subunits, c-Jun and c-Fos. In summary, the present study demonstrated that in 4T-1 mouse triple-negative breast cancer cells the anti-metastatic effect of arctigenin is mediated by the inhibition of MMP-9 activity and by the inhibition of the metastasis-enhancing factors MMP-9, MMP-3 and COX-2, due to the suppression of the MAPK/AP-1 signaling pathway. The results of the current study demonstrated that arctigenin exhibits a potential for preventing cell migration and invasion in triple negative breast cancer.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1635-1644
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• 2018

Asterias amurensis (starfish) is a marine organism that is harmful to the fishing industry, but is also a potential source of functional materials. The present study was conducted to analyze the profiles of fatty acids extracted from A. amurensis tissues and their anti-inflammatory effects on RAW264.7 macrophage cells. In different tissues, the component ratios of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids differed; particularly, polyunsaturated fatty acids such as dihomo-gamma-linolenic acid (20:3n-6) and eicosapentaenoic acid (20:5n-3) were considerably different. In lipopolysaccharide-stimulated RAW264.7 cells, fatty acids from A. amurensis skin, gonads, and digestive glands exhibited anti-inflammatory activities by reducing nitric oxide production and inducing nitric oxide synthase gene expression. Asterias amurensis fatty acids effectively suppressed the expression of inflammatory cytokines such as tumor necrosis $factor-{\alpha}$, interleukin-$1{\beta}$, and interleukin-6 in lipopolysaccharide-stimulated cells. Cyclooxygenase-2 and prostaglandin $E_2$, which are critical inflammation biomarkers, were also significantly suppressed. Furthermore, A. amurensis fatty acids reduced the phosphorylation of nuclear $factor-{\kappa}B$ p-65, p38, extracellular signal-related kinase 1/2, and c-Jun N-terminal kinase, indicating that these fatty acids ameliorated inflammation through the nuclear $factor-{\kappa}B$ and mitogen-activated protein kinase pathways. These results provide insight into the anti-inflammatory mechanism of A. amurensis fatty acids on immune cells and suggest that the species is a potential source of anti-inflammatory molecules.

• 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.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3169-3174
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• 2014

Numerous studies have examined the role of flavonoids in modulating inflammatory responses in vitro. In this study, we found a novel flavonoid, 3,6,3'-trihydroxyflavone (1), with anti-inflammatory effects. Anti-inflammatory activity and mechanism of action were examined in mouse macrophages stimulated with lipopolysaccharide (LPS). Our results showed that the anti-inflammatory effects of 1 are mediated via p38 mitogen-activated protein kinase (p38 MAPK), Jun-N terminal kinase (JNK), and the extracellular-signal-regulated kinase (ERK) pathway in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Binding studies revealed that 1 had a high binding affinity to JNK1 ($1.568{\times}10^8M^{-1}$) and that the 3- and 6-hydroxyl groups of the C-ring and A-ring of 1 participated in hydrogen bonding interactions with the side chains of Asn114 and Lys55, respectively. The oxygen at the 3' position of the B-ring formed a hydrogen bond with side chain of Met111. Therefore, 1 could be a potential inhibitor of JNKs, with potent anti-inflammatory activity.

• BMB Reports
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• v.50 no.3
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• pp.150-155
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• 2017

Non-small-cell lung cancer (NSCLC) is the third most common cancer that spreads to the bone, resulting in osteolytic lesions caused by hyperactivation of osteoclasts. Activating mutations in epidermal growth factor receptor-tyrosine kinase (EGF-TK) are frequently associated with NSCLC, and afatinib is a first-line therapeutic drug, irreversibly targeting EGF-TK. However, the effects of afatinib on osteoclast differentiation and activation as well as the underlying mechanism remain unclear. In this study, afatinib significantly suppressed receptor activator of nuclear factor ${\kappa}B$ (RANK) ligand (RANKL)-induced osteoclast formation in bone marrow macrophages (BMMs). Consistently, afatinib inhibited the expression of osteoclast marker genes, whereas, it upregulated the expression of negative modulator genes. The bone resorbing activity of osteoclasts was also abrogated by afatinib. In addition, afatinib significantly inhibited RANKL-mediated Akt/protein kinase B and c-Jun N-terminal kinase phosphorylation. These results suggest that afatinib substantially suppresses osteoclastogenesis by downregulating RANK signaling pathways, and thus may reduce osteolysis after bone metastasis.

• Journal of the Korean Chemical Society
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• v.66 no.4
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• pp.298-304
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• 2022

The present study was designed to investigate the molecular mechanisms of DK-5-62, a novel (-)-catechin derivative on HCT116 human colorectal cancer cells. DK-5-62 inhibited the proliferation in dose- and time-dependent manner accompanied by the morphological changes. Effects of DK-5-62 appeared to be mediated by the induction of apoptosis, as manifested through DNA-binding dye Hoechst 33258 staining. Analysis of the mechanism of these events indicated that DK-5-62-treated cells exhibited an increased ratio of Bax/Bcl-2, resulting in the activation of caspase-9, caspase-3, and poly-ADP-ribose polymerase in a dose-dependent manner. Moreover, DK-5-62-induced apoptosis was accompanied by phosphorylation of the mitogen-activated protein kinase family, c-Jun N-terminal kinase, p38, and extracellular signal-regulated kinase. These results suggest that HCT116 cells are moderately sensitive to growth inhibition by DK-5-62 via apoptosis, as evidenced by activation of ERK/p38/Bcl-2 family signaling, as well as alteration in caspase-9 and caspase-3.

• Archives of Pharmacal Research
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• v.26 no.9
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• pp.739-746
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• 2003

Ultraviolet B (UVB) is known to induce apoptosis in human melanocytes. Here we show the cytoprotective effect of sphingosine-1-phosphate (S1P) against UVB-induced apoptosis. We also show that UVB-induced apoptosis of melanocytes is mediated by caspase-3 activation and poly(ADP-ribose) polymerase (PARP) cleavage, and that S1P prevents apoptosis by inhibiting this apoptotic pathway. We further investigated three major mitogen-activated protein (MAP) kinases after UVB irradiation. UVB gradually activated c-Jun N-terminal kinase (JNK) and p38 MAP kinase, while extracellular signal-regulated protein kinase (ERK) was inactivated transiently. Blocking of the p38 MAP kinase pathway using SB203580 promoted cell survival and inhibited the activation of caspase-3 and PARP cleavage. These results suggest that p38 MAP kinase activation may play an important role in the UVB-induced apoptosis of human melanocytes. To explain this cytoprotective effect, we next examined whether S1P could inhibit UVB-induced JNK and p38 MAP kinase activation. However, S1P was not found to have any influence on UVB-induced JNK or p38 MAP kinase activation. In contrast, S1P clearly stimulated the phosphorylation of ERK, and the specific inhibition of the ERK pathway using PD98059 abolished the cytoprotective effect of S1P. Based on these results, we conclude that the activation of p38 MAP kinase plays an important role in UVB-induced apoptosis, and that S1P may show its cytoprotective effect through ERK activation in human melanocytes.

• BMB Reports
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• v.52 no.8
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• pp.502-507
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• 2019

Translation is a costly, but inevitable, cell maintenance process. To reduce unnecessary ATP consumption in cells, a fine-tuning mechanism is needed for both ribosome biogenesis and translation. Previous studies have suggested that the ribosome functions as a hub for many cellular signals such as ribotoxic stress response, mammalian target of rapamycin (mTOR), and ribosomal S6 kinase (RSK) signaling. Therefore, we investigated the relationship between ribosomes and mitogen-activated protein kinase (MAPK) activation under ribotoxic stress conditions and found that the activation of c-Jun N-terminal kinases (JNKs) was suppressed by ribosomal protein knockdown but that of p38 was not. In addition, we found that JNK activation is driven by the association of inactive JNK in the 80S monosomes rather than the polysomes. Overall, these data suggest that the activation of JNKs by ribotoxic stress is attributable to 80S monosomes. These 80S monosomes are active ribosomes that are ready to initiate protein translation, rather than polysomes that are already acting ribosomes involved in translation elongation.