• The Korean Journal of Physiology and Pharmacology
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• v.5 no.6
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• pp.451-456
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• 2001

In rat hippocampus, kainic acid (KA; 10 mg/kg; i.p.) increased the phosphorylated forms of ERK1/2 (p-ERK1/2) and Jun kinase1 (p-JNK1), but not p-JNK2 and p38 (p-p38). The preadministration with cycloheximide (CHX; 5 mg/kg; i.p.) inhibited KA-induced increase of p-JNK1, but not p-ERK1/2. Surprisingly, the phosphorylated upstream MAP kinase kinases (p-MKKs) were not correlated with their downstream MAP kinases. The basal p-MKK1/2 levels were completely abolished by KA, which were reversed by CHX. In addition, p-MKK4 and p-MKK3/6 levels were enhanced by CHX alone, but were attenuated by KA. Thus, our results showed that KA increased the p-ERK and p-JNK levels in rat hippocampus, which were not parallel with their classical upstreamal kinases.

• YAKHAK HOEJI
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• v.52 no.3
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• pp.182-187
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• 2008

Salicylate (SA) was shown to alleviate insulin resistance. Here, we showed that SA inhibited Ser731 phosphorylation of insulin receptor substrate 1 (IRS1) and S6 kinase activation, and enhanced tyrosine phosphorylation of IRS1 in response to insulin or amino acid. Experiments using a cJun N-terminal kinase (JNK)-deficient cell and an IRS1 JNK-binding mutant showed that JNK is not required for Ser731 phosphorylation. A two-week treatment of obese mice with SA resulted in decreased Ser731 phosphorylation and enhanced insulin signaling. These results suggest that SA enhances insulin signaling by inhibiting Ser731 phosphorylation of IRS1.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.47-47
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• 2023

Paeonia lactiflora roots (PLR) are a medicinal plant widely used for treating inflammatory diseases. However, PLR has been recently reported to increase the production of proinflammatory mediators and activates phagocytosis in macrophages. Thus, in this study, we tried to verify the macrophage activation of PLR and elucidate its mechanism of action. PLR upregulated the production of proinflammatory mediators and activated phagocytosis in RAW264.7 cells. However, these effects were reversed by inhibition of TLR2/4. In addition, the inhibition of p38, JNK, and ERK1/2 reduced the PLR-mediated production of proinflammatory mediators, and the PLR-mediated activation of p38, JNK, and ERK1/2 was blocked by the TLR4 inhibition. These findings indicate that PLR may activate macrophages through TLR4-dependent activation of p38, JNK, and ERK1/2. These indicate that PLR has immunostimulatory activity. Thus, it is believed that PLR can be used as a functional food agent that enhances the immune system.

• Biomolecules & Therapeutics
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• v.21 no.5
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• pp.332-337
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• 2013

Microglial activation plays an important role in the development and progression of various neurological disorders such as cerebral ischemia, multiple sclerosis, and Alzheimer's disease. Thus, controlling microglial activation can serve as a promising therapeutic strategy for such brain diseases. In the present study, we showed that kalopanaxsaponin A, a triterpenoid saponin isolated from Kalopanax pictus, inhibited inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumor necrosis factor (TNF)-${\alpha}$ expression in lipopolysaccharide (LPS)-stimulated microglia, while kalopanaxsaponin A increased anti-inflammatory cytokine interleukin (IL)-10 expression. Subsequent mechanistic studies revealed that kalopanaxsaponin A inhibited LPS-induced DNA binding activities of NF-${\kappa}B$ and AP-1, and the phosphorylation of JNK without affecting other MAP kinases. Furthermore, kalopanaxsaponin A inhibited the intracellular ROS production with upregulation of anti-inflammatory hemeoxygenase-1 (HO-1) expression. Based on the previous reports that JNK pathway is largely involved in iNOS and proinflammatory cytokine gene expression via modulating NF-${\kappa}B$/AP-1 and ROS, our data collectively suggest that inhibition of JNK pathway plays a key role in anti-inflammatory effects of kalopanaxsaponin A in LPS-stimulated microglia.

• BMB Reports
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• v.46 no.12
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• pp.594-599
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• 2013

The anti-inflammatory activity of eriodictyol and its mode of action were investigated. Eriodictyol suppressed tumor necrosis factor (mTNF)-${\alpha}$, inducible nitric oxide synthase (miNOS), interleukin (mIL)-6, macrophage inflammatory protein (mMIP)-1, and mMIP-2 cytokine release in LPS-stimulated macrophages. We found that the anti-inflammatory cascade of eriodictyol is mediated through the Toll-like Receptor (TLR)4/CD14, p38 mitogen-activated protein kinases (MAPK), extracellular-signal-regulated kinase (ERK), Jun-N terminal kinase (JNK), and cyclooxygenase (COX)-2 pathway. Fluorescence quenching and saturation-transfer difference (STD) NMR experiments showed that eriodictyol exhibits good binding affinity to JNK, $8.79{\times}10^5M^{-1}$. Based on a docking study, we propose a model of eriodictyol and JNK binding, in which eriodictyol forms 3 hydrogen bonds with the side chains of Lys55, Met111, and Asp169 in JNK, and in which the hydroxyl groups of the B ring play key roles in binding interactions with JNK. Therefore, eriodictyol may be a potent anti-inflammatory inhibitor of JNK.

• Animal cells and systems
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• v.10 no.2
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• pp.79-83
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• 2006

Tissue plasminogen activator (tPA) is used to lyse clots and reperfuse brain in ischemic stroke. However, sideeffects of intracerebral hemorrhage (ICH) and edema limit their clinical application. In part, these phenomena has been linked with elevations in matrix metalloproteinase-9 (MMP-9) in neurovascular unit. However little is known about their regulatory signaling pathways in brain cells. Here, I examine the role of MAP kinase pathways in tPA-induced MMP-9 regulation in rat cortical astrocytes. tPA $(1-10\;{\mu}g/ml)$ induced dose-dependent elevations in MMP-9 and MMP-2 in conditioned media. Although tPA increased phosphorylation in two MAP kinases (ERK, JNK), only inhibition of the JNK pathway by the JNK inhibitor SP600126 significantly reduced MMP-9 upregulation. Neither ERK inhibition with U0126 nor p38 inhibition with SB203580 had any significant effects. Taken together, these results suggest that c-jun N-terminal kinase (JNK) plays an essential role for tPA-induced MMP-9 upregulation.

• Biomolecules & Therapeutics
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• v.28 no.1
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• pp.104-109
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• 2020

Probenecid is a representative drug used in the treatment of gout. A recent study showed that probenecid effectively inhibits oxidative stress in neural cells. In the present study, we investigated whether probenecid can affect osteoclast formation through the inhibition of reactive oxygen species (ROS) formation in RAW264.7 cells. Lipopolysaccharide (LPS)-induced ROS levels were dose-dependently reduced by probenecid. Fluorescence microscopy analysis clearly showed that probenecid inhibits the generation of ROS. Western blot analysis indicated that probenecid affects two downstream signaling molecules of ROS, cyclooxygenase 2 (COX-2) and c-Jun N-terminal kinase (JNK). These results indicate that probenecid inhibits ROS generation and exerts antiosteoclastogenic activity by inhibiting the COX-2 and JNK pathways. These results suggest that probenecid could potentially be used as a therapeutic agent to prevent bone resorption.

• Biomolecules & Therapeutics
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• v.26 no.2
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• pp.191-200
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• 2018

Chalcone, (2E)-1,3-Diphenylprop-2-en-1-one, and its synthetic derivatives are known to possess anti-oxidative and anti-inflammatory properties. In the present study, we prepared a novel synthetic chalcone compound, (E)-1-(4-hydroxyphenyl)-3-(2-(trifluoromethoxy)phenyl)prop-2-en-1-one name (YJI-7), and investigated its inhibitory effects on endotoxin-stimulated production of reactive oxygen species (ROS) and expression of inflammatory mediators in macrophages. We demonstrated that treatment of RAW 264.7 macrophages with YJI-7 significantly suppressed lipopolysaccharide (LPS)-stimulated ROS production. We also found that YJI-7 substantially decreased NADPH oxidase activity stimulated by LPS, indicating that YJI-7 regulates ROS production via modulation of NADPH oxidase in macrophages. Furthermore, YJI-7 strongly inhibited the expression of a number of inflammatory mediators in a gene-selective manner, suggesting that YJI-7 possesses potent anti-inflammatory properties, as well as anti-oxidative activity. In continuing experiments to investigate the mechanisms that could underlie such biological effects, we revealed that YJI-7 suppressed phosphorylation of p38MAPK and JNK stimulated by LPS, whereas no significant effect on ERK was observed. Furthermore, LPS-stimulated production of ROS, activation of NADPH oxidase and expression of inflammatory mediators were markedly suppressed by treatment with selective inhibitor of p38MAPK (SB203580) and JNK (SP600125). Taken together, these results demonstrated that YJI-7, a novel synthetic chalcone derivative, suppressed LPS-stimulated ROS production via modulation of NADPH oxidase and diminished expression of inflammatory mediators, at least in part, via down-regulation of p38MAPK and JNK signaling in macrophages.

• Journal of Sasang Constitutional Medicine
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• v.21 no.1
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• pp.139-149
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• 2009

1. Objectives The roots of Sophora flavescens Aiton (SFA) are widely used as a herbal remedy for allergic inflammation. In this study, we invested the effect of SFA on passive cutaneous anaphylaxis reaction and histamin releas and we demonstrated that SFA suppressed the production of pro-inflammatory cytokines, such as tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin- 6 (IL-6), and interleukin -8 (IL-8), through inhibition of the $NF{\kappa}B$, JNK and p38 pathway in the human mast cell line, HMC-1. 2. Methods To accomplish this, we invested passive cutaneous anaphylaxis reaction and histamin release at an animal experiment. In addition, we investigated the effect of SFA on the production of inflammation-related cytokines in HMC-1 cells that were co-treated with PMA and A23187, which can induce production of pro-inflammatory cytokines. 3. Results and Conclusions SFA induced passive cutaneous anaphylaxis reaction and histamin releas and supressed the expression of TNF-${\alpha}$, IL-6, and IL-8. In addition, the protein levels of TNF-${\alpha}$ were also decreased by SFA treatment. Furthermore, SFA inhibited the nuclear translocation of nuclear factor $NF{\kappa}B$ through inhibition of the phosphorylation and degradation of $I{\kappa}B-{\alpha}$, which is an inhibitor of $NF{\kappa}B$. Moreover, SFA also inhibited induction of MAPKs (JNK, p38) and $NF{\kappa}B$ promoter-mediated luciferase activity. Taken together, these results suggest that SFA could be used as a treatment for mast cell-derived allergic inflammatory diseases.

• Biomolecules & Therapeutics
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• v.30 no.5
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• pp.455-464
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• 2022

Efonidipine, a calcium channel blocker, is widely used for the treatment of hypertension and cardiovascular diseases. In our preliminary study using structure-based virtual screening, efonidipine was identified as a potential inhibitor of c-Jun N-terminal kinase 3 (JNK3). Although its antihypertensive effect is widely known, the role of efonidipine in the central nervous system has remained elusive. The present study investigated the effects of efonidipine on the inflammation and cell migration induced by lipopolysaccharide (LPS) using murine BV2 and human HMC3 microglial cell lines and elucidated signaling molecules mediating its effects. We found that the phosphorylations of JNK and its downstream molecule c-Jun in LPS-treated BV2 cells were declined by efonidipine, confirming the finding from virtual screening. In addition, efonidipine inhibited the LPS-induced production of pro-inflammatory factors, including interleukin-1β (IL-1β) and nitric oxide. Similarly, the IL-1β production in LPS-treated HMC3 cells was also inhibited by efonidipine. Efonidipine markedly impeded cell migration stimulated by LPS in both cells. Furthermore, it inhibited the phosphorylation of inhibitor kappa B, thereby suppressing nuclear translocation of nuclear factor-κB (NF-κB) in LPS-treated BV2 cells. Taken together, efonidipine exerts anti-inflammatory and anti-migratory effects in LPS-treated microglial cells through inhibition of the JNK/NF-κB pathway. These findings imply that efonidipine may be a potential candidate for drug repositioning, with beneficial impacts on brain disorders associated with neuroinflammation.