• Toxicological Research
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• 제17권
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• pp.251-256
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• 2001

The expression of phase II detoxifying enzymes is affected by a variety of compounds and the induction of the enzymes plays an essential role in chemoprevention. A variety of phytochemicals such as sulfur-containing chemoprotective agents (SCC) may trigger cellular signals and activate phase II gene expression through ARE activation. see induces glutathione S-transferases. Studies were conducted to investigate the role of mitogen-activated protein (MAP) kinase and phosphatidylinositol 3-kinase (PI3-kinase) in the induction of GST (e.g. rGSTA2) by sec. We also studied the MAP kinase pathway responsible for the GST expression by see and compared that with the pathway activated by oxidative stress as a result of sulfur amino acids deprivation (SAAD). see inhibited phosphorylation of ERK1/2 although the effect of see on JNK and p38 MAP kinase was minimal. Wortmannin and LY294002. PI3-kinase inhibitors. abolished the increases in rGSTA2 mRNA and protein levels by SCC. Deprivation of cystine and methionine caused oxidative stress in H4IIE cells. as evidenced by a decrease in the reduced glutathione and an increase in prooxidant production. Electrophoretic mobility shift assay revealed that the ARE complex consisting of Nrf-1/2 and Maf proteins was activated 12~48 h. The rGSTA2 mRNA and protein levels were increased by SAAD. Activation of ARE and induction of rGSTA2 were both completely inhibited by PI3-kinase inhibitors. Inhibition of p38 MAP kinase by SB203580 prevented the ARE-mediated rGSTA2 induction. The results of this study showed that PI3-kinase might play an essential role in the ARE-mediated rGSTA2 induction by see or SAAD and that the dual MAP kinase pathways were responsible for the enzyme induction.

• 대한물리치료과학회지
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• 제11권1호
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• pp.20-27
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• 2004

It is widely accepted that smooth muscle contraction is triggered by intracellular $Ca^{2+}$ ($[Ca^{2+}]_i$) released from intracellular $Ca^{2+}$ stores such as sarcoplasmic reticulum (SR) and from the extracellular space, The increased $[Ca^{2+}]_i$ can phosphorylate the 20-kDa myosin light chain ($MLC_{20}$) by activating MLC kinase (MLCK), and this initiates smooth muscle contraction. In addition to the $[Ca^{2+}]_i$-MLCK-tension pathway, a number of intracellular signal molecules, including mitogen-activated protein kinase (MAPK), protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K), and Rho-associated coiled coil-forming protein kinase (ROCK), play important roles in the regulation of smooth muscle contraction. However, the mechanisms regulating contraction of caldesmon (CaD), actin-binding protein, are not entirely elucidated in the presence of $Ca^{2+}$. It is known that CaD tightly interacts with actin and inhibits actomyosin ATPase activity. Therefore, the purpose of the present study was to investigate the roles of $Ca^{2+}$-dependent CaD in smooth muscle contraction. Endothelin-1 (ET-1), G-protein coupled receptor agonist and vasoconstrictor, increased both vascular smooth contraction and phosphorylation of CaD in the presence of $Ca^{2+}$. These results suggest that ET-1 induces contraction and phosphorylation of CaD in rat aortic smooth muscle, which may he mediated by the increase of $[Ca^{2+}]_i$.

• International Journal of Oral Biology
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• 제46권1호
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• pp.51-59
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• 2021

Periodontal disease is an inflammatory disease that affects the destruction of the bone supporting the tooth and connective tissues surrounding it. Periodontal ligament fibroblasts (PDLFs) induce overexpression of matrix metalloproteinase (MMP) involved in periodontal disease's inflammatory destruction. Osteoclasts take part in physiological bone remodeling, but they are also involved in bone destruction in many kinds of bone diseases, including osteoporosis and periodontal disease. This study examined the effect of baicalin on proteolytic enzymes' production and secretion of inflammatory cytokines in PDLFs and RAW 264.7 cells under the lipopolysaccharide (LPS)-induced inflammatory conditions. Baicalin inhibited the expression of the protein, MMP-1 and MMP-2, without affecting PDLFs' cell viability, suggesting its possibility because of the inhibition of phosphorylation activation of mitogen-activated protein kinase's p38, and the signal transduction process of nuclear factor κB (NFκB)-related protein. Also, baicalin reduced the expression of MMP-8 and MMP-9 in RAW 264.7 cells. This reduction is thought to be due to the inhibition of the signal transduction process of NFκB-related proteins affected by inhibiting p65RelA phosphorylation. Also, baicalin inhibited the secretion of nitric oxide and interleukin-6 induced by LPS in RAW 264.7 cells. These results suggest that baicalin inhibits connective tissue destruction in periodontal disease. The inhibition of periodontal tissue destruction may be a therapeutic strategy for treating inflammatory periodontal-diseased patients.

• 대한본초학회지
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• 제22권2호
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• pp.155-161
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• 2007

Objectives: Evidences suggests that Ginkgo biloba, a widely used traditional medicine, shows a hypoglycemic effect. Thus, we investigatd the effect of G. biloba extract (GB) on glucose uptake in L6 rat skeletal muscle cells. Method : Effect of GB on glucose uptake and phosphatidylinositol (PI) 3-kinase activity were assessed using Glucose uptake assay and PI 3-kinase assay, respectively. Also, AMP-activated protein kinase (AMPK), p38 mitogen activated protein kinase (p38 MAPK) expression were identified by Western blot. Results : Glucose uptake assay revealed that GB increased glucose uptake about 2.5-fold compared to thecontrol. GB stimulated the activity of PI 3-kinase which is a major switch element on the glucose uptake pathway. About a 6.5-fold increase in activity of PI 3-kinase was observed with GB. We then assessed the activity of AMPK, another regulatory molecule on the glucose uptake pathway. The result was that GB increased the phosphorylation level of both AMPK ${\alpha}$l and ${\alpha}$2. The activity of p38 MAPK, a downstream mediator of AMPK, was also increased by CB. Conclusion : These results suggest that GB may stimulate glucose uptake through both PI 3-kinase and AMPK mediated pathways in L6 skeletal muscle cells thereby contributing to glucose homeostasis.

• Mycobiology
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• 제37권3호
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• pp.161-170
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• 2009

Cryptococcus neoformans is a basidiomycete human fungal pathogen that causes meningoencephalitis in both immunocompromised and immunocompetent individuals. The ability to sense and respond to diverse extracellular signals is essential for the pathogen to infect and cause disease in the host. Four major stress-activated signaling (SAS) pathways have been characterized in C. neoformans, including the HOG (high osmolarity glycerol response), PKC/Mpk1 MAPK (mitogen-activated protein kinase), calcium-dependent calcineurin, and RAS signaling pathways. The HOG pathway in C. neoformans not only controls responses to diverse environmental stresses, including osmotic shock, UV irradiation, oxidative stress, heavy metal stress, antifungal drugs, toxic metabolites, and high temperature, but also regulates ergosterol biosynthesis. The PKC(protein kinase C)/Mpk1 pathway in C. neoformans is involved in a variety of stress responses, including osmotic, oxidative, and nitrosative stresses and breaches of cell wall integrity. The $Ca^{2+}$/calmodulin- and Ras-signaling pathways also play critical roles in adaptation to certain environmental stresses, such as high temperature and sexual differentiation. Perturbation of the SAS pathways not only impairs the ability of C. neoformans to resist a variety of environmental stresses during host infection, but also affects production of virulence factors, such as capsule and melanin. A drug(s) capable of targeting signaling components of the SAS pathway will be effective for treatment of cryptococcosis.

• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.277-286
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• 2022

Schizophragma hydrangeoides (S. hydrangeoides) is a vine endogenous to Jeju Island and Ulleungdo, where it grows attached to the foothills and rock surfaces. Previous research has mostly focused on the whitening effect of S. hydrangeoides leaf extract. In this study, we investigated S. hydrangeoides leaf extract further, and detected four phytochemicals in the extract: chlorogenic acid, quercetin-3-O-glucosyl-(1-2)-rhamnoside, quercetin-3-O-xylosyl-(1-2)-rhamnoside, and quercitrin. We pretreated human dermal fibroblast (HDFn) cells with previously established concentrations of the four compounds for 1 h before ultraviolet A (UVA) irradiation. Among the four compounds, quercetin-3-O-glucosyl-(1-2)-rhamnoside (Q-3-GR) best inhibited matrix metalloproteinase-1 (MMP-1) levels. Thus, we investigated the protective effects of Q-3-GR on photoaging and its underlying mechanisms. Q-3-GR significantly reduced MMP-1 production and inhibited MMP-1 protein expression in UVA-irradiated HDFn cells. Furthermore, Q-3-GR increased procollagen type I production and protein expression. Q-3-GR exerted its anti-photoaging effects by downregulating the mitogen-activated protein kinase/ activator protein-1 signaling pathway, and upregulating the transforming growth factor-β/Smad signaling pathway. Thus, S. hydrangeoides leaf-derived Q-3-GR is a potential potent cosmetic ingredient for UV-induced skin aging.

• Biomolecules & Therapeutics
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• 제21권6호
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• pp.435-441
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• 2013

Emodin, a naturally occurring anthraquinone derivative isolated from Polygoni cuspidati radix, has several beneficial pharmacologic effects, which include anti-cancer, anti-diabetic, and anti-inflammatory activities. In this study, the authors examined the effect of emodin on the production of proinflammatory cytokines, such as, tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-6, in mouse bone marrow-derived mast cells (BMMCs) stimulated with phorbol 12-myristate 13-acetate (PMA) plus the calcium ionophore A23187. To investigate the mechanism responsible for the regulation of pro-inflammatory cytokine production by emodin, the authors assessed its effects on the activations of transcriptional factor nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and mitogen-activated protein kinases (MAPKs). Emodin attenuated the nuclear translocation of (NF)-${\kappa}B$ p65 and its DNA-binding activity by reducing the phosphorylation and degradation of $I{\kappa}B{\alpha}$ and the phosphorylation of $I{\kappa}B$ kinase B (IKK). Furthermore, emodin dose-dependently attenuated the phosphorylations of MAPKs, such as, extracellular signal-regulated kinase 1/2 (ERK1/2), p38 MAP kinase, and the stress-activated protein kinases (SAPK)/c-Jun-N-terminal kinase (JNK). Taken together, the findings of this study suggest that the anti-inflammatory effects of emodin on PMA plus A23187-stimulated BMMCs are mediated via the inhibition of NF-${\kappa}B$ activation and of the MAPK pathway.

• 대한본초학회지
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• 제22권2호
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• pp.147-153
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• 2007

Objectives : Sophora flavescens (SF) is widely used in traditional herbal medicine in Korea and is well recognized for its anti-inflammatory effect. However, its effect on Tumornecrosis factor alpha (Tnf) production in BV2 microglial cell is not yet known. Methods : We investigated the effect of SF on the production and expression of Tnf, a well known inflammatory mediator, in lipopolysaccaride (LPS)-activated BV2 microglial cells. Results : The LPS-induced Tnf production was markedly reduced by treatment with SF (50 ${\mu}g/ml$). In reverse transcription polymerase chain reaction (RT-PCR) analysis, SF suppressed the LPS activated expression of Tnf mRNA. In addition, Western blot analysis confirmed that SF suppressed the expression of Tnf. Sophora flavescens also inhibited the LPS-induced phosphylation of extracellular signal-regulated kinases (ERK), which mediate the Tnfproduction signaling pathway whereas LPS-induced phosphylation of p38 mitogen activated protein kinase (p38 MAPK), and c-Jun NH2-terminal kinases (JNK) was not inhibited by SF, which implies that SF suppresses LPS-induced Tnf production via the ERK mediated pathway. Conclusion : Taken together, these findings indicated that SF inhibits LPS-induce Tnf production, and that this inhibitory effect is mediated via the ERK pathway.

• Animal Bioscience
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• 제35권7호
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• pp.964-974
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• 2022

Objective: The highly pathogenic avian influenza virus (HPAIV) is a threat to the poultry industry and economy and remains a potential source of pandemic infection in humans. Antiviral genes are considered a potential factor for studies on HPAIV resistance. Therefore, in this study, we investigated gene expression related to the mitogen-activated protein kinase (MAPK) signaling pathway by comparing non-infected, HPAI-infected resistant, and susceptible Ri chicken lines. Methods: Resistant (Mx/A; BF2/B21) and susceptible Ri chickens (Mx/G; BF2/B13) were selected by genotyping the Mx and BF2 genes. Then, the tracheal tissues of non-infected and HPAIV H5N1 infected chickens were collected for RNA sequencing. Results: A gene set overlapping test between the analyzed differentially expressed genes (DEGs) and functionally categorized genes was performed, including biological processes of the gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathways. A total of 1,794 DEGs were observed between control and H5N1-infected resistant Ri chickens, 432 DEGs between control and infected susceptible Ri chickens, and 1,202 DEGs between infected susceptible and infected resistant Ri chickens. The expression levels of MAPK signaling pathway-related genes (including MyD88, NF-κB, AP-1, c-fos, Jun, JunD, MAX, c-Myc), cytokines (IL-1β, IL-6, IL-8), type I interferons (IFN-α, IFN-β), and IFN-stimulated genes (Mx1, CCL19, OASL, and PRK) were higher in H5N1-infected than in non-infected resistant Ri chickens. MyD88, Jun, JunD, MAX, cytokines, chemokines, IFNs, and IFN-stimulated expressed genes were higher in resistant-infected than in susceptible-infected Ri chickens. Conclusion: Resistant Ri chickens showed higher antiviral activity compared to susceptible Ri chickens, and H5N1-infected resistant Ri chickens had immune responses and antiviral activity (cytokines, chemokines, interferons, and IFN-stimulated genes), which may have been induced through the MAPK signaling pathway in response to H5N1 infection.

• 셀메드
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• 제13권6호
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• pp.7.1-7.6
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• 2023

Raphanus sativus L. has been reported to have anti-inflammatory and anti-tumor activity. However, the anti-inflammatory effect and mechanism of action of the Raphanus sativus L. seeds (RSS) with or without oil are still unknown. This study was undertaken to investigate the in-vitro anti-inflammatory effect with or without oil in the RSS on RAW 264.7 cells stimulated by lipopolysaccharide (LPS). Results showed the suppressed LPS-induced secretion of pro-inflammatory mediators such as nitric oxide (NO), inflammatory cytokine (IL-6, TNF-α). Additionally, a decrease in protein expression of iNOS was observed, but nuclear translocation of NF-κB p65 was not inhibited. To elucidate the underlying mechanism of the anti-inflammatory effect of RSS, the involvement of mitogen-activated protein kinase (MAPK) signaling pathways was examined. We also found that RSS blocked LPS-induced phosphorylation of c-Jun N-terminal kinase/stress-activated protein kinase (JNK) signaling but did not affect the phosphorylation of p38 MAPK and extracellular signal-regulated kinase (ERK) 1/2. These results suggest that RSS may have potential as an anti-inflammatory agent through the inhibition of LPS-induced inflammatory cytokine production via regulation of the JNK pathway.