• Preventive Nutrition and Food Science
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• v.8 no.2
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• pp.124-129
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• 2003

This study was designed to investigate whether a methanol extract of chlorella can suppress oxidative stress and nuclear factor kB (NFkB) activation in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophage cells. Treatment of RAW 264.7 cells with chlorella methanol extract (25, 50, and 100 $\mu$g/mL) significantly reduced LPS-stimulated nitric oxide production in a dose-dependent manner. Treatments with chlorella methanol extract at all concentrations also reduced thiobarbituric acid-reactive substances accumulation and enhanced glutathione level at 50 and 100 $\mu$g/mL levels. The specific DNA binding activities of NFkB on nuclear extracts in cells treated with 50 $\mu$g/mL and 100 $\mu$g/mL chlorella methanol extracts were significantly suppressed. These results suggest that chlorella methanol extract has mild antioxidative activity and the ability to suppress intracellular oxidative stress and NFkB activation.

• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.62-68
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• 2005

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.479-491
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• 1998

In order to know the pathogenesis of adult respiratory distress syndrome (ARDS) in association with the oxidative stress by neutrophils, the role of platelet activating factor (1-0-alkyl-2-acetyl-snglycero-3-phosphocholine, PAF) was investigated during acute lung injury induced by interleukin- $1{\alpha}$ (IL-1) in rats. An insufflation of IL-1 into the rat's trachea increased the acetyltransferase activity in the lung and the increase of PAF content was followed. As evidences of acute lung injury by neutrophilic respiratory burst, lung leak index, myeloperoxidase activity, numbers of neutrophils in the bronchoalveolar lavage fluid, neutrophilic adhesions to endothelial cells and NBT positive neutrophils were increased after IL-1 treatment. In addition, a direct instillation of PAF into the trachea caused acute lung leak and the experimental results showed a similar pattern in comparison with IL-1 induced acute lung injury. For the confirmation of oxidative stress during acute lung leak by IL-1 and PAF, a histochemical electron microscopy was performed. In IL-1 and PAF treated lungs of rats, the deposits of cerrous perhydroxide were found. To elucidate the role of PAF, an intravenous injection of PAF receptor antagonist, WEB 2086 was given immediately after IL-1 or PAF treatment. WEB 2086 decreased the production of hydrogen peroxide and the acute lung leak. In ultrastructural study, WEB 2086 mitigated the pathological changes induced by IL-1 or PAF. The nuclear factor kappa B (NFkB) was activated by PAF and this activation was inhibited by WEB 2086 almost completely. Based on these experimental results, it is suggested that the PAF produced in response to IL-1 through the remodeling pathway has the major role for acute lung injury by neutrophilic respiratory burst. In an additional experiment, we can also come to conclude that the activation of the NFkB by PAF is thought to be the fundamental mechanism to initiate the oxidative stress by neutrophils causing release of proinflammatory cytokines and activation of phospholipase $A_2$.

• Korean journal of applied entomology
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• v.45 no.1 s.142
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• pp.15-24
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• 2006

Inhibitor kB (IkB)-like gene has been found in the genome of Cotesia plutellae bracovirus (CpBV), which is the obligatory symbiont of an endoparsitoid wasp, C. plutellae. The open reading frame of CpBV-IkB was 417 bp and encoded 138 amino acids. Four ankyrin repeat domains were found in CpBV-IkB, which shared high homology with other known polydnavirus IkBs. Considering a presumptive cellular IkB based on Drosophila Cactus, CpBV-IkB exhibited a truncated structure with deletion of signal-receiving domains, which suggested its irreversible inhibitory role in NFkB signal transduction pathway of the parasitized host in response to the wasp parasitization. CpBV-IkB was expressed only in the parasitized diamondback moth, Plutella flostella. Its expression was estimated by quantitative RT-PCR during parasitization period, showing a constitutive expression pattern from the first day of parasitization. An indirect functional analysis of CpBV-IkB was conducted and suggested a hypothesis of host antivirus inhibition.

• YAKHAK HOEJI
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• v.47 no.1
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• pp.31-36
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• 2003

To investigate the effect of protein kinase on melanin production via cAMP-dependent pathway, we measured the melanin amount and tyrosinase activity in B16 melanoma cells stimulated by alpha-melanocyte stimulating hormone (MSH), forskolin and 8-Br-cAMP. MSH, forskolin and 8-Br-cAMP significantly increased both melanin production and tyrosinase activity in B16 cells. Melanin production and tyrosinase activity by MSH are significantly inhibited by cyclic AMP-dependent protein kinase inhibitor (KT5720) and protein kinase C down-regulation treated with PMA. Bisindolmaleimide (1$\mu$M), protein kinase C inhibitor, significantly inhibited melanin production and tyrosinase activity stimulated by MSH, forskolin and 8-Br-cAMP with the following order of potency: MSH＞forskolin＞8-Br-cAMP. Tyrosine kinase inhibitor, genistein and DHC, significantly inhibited both, but the inhibitory effect was more potent in 8-Br-cAMP-stimulated B16 cells than MSH-stimulated cells. NFkB inhibitor (parthenolide) significantly inhibited melanin production and tyrosinase activity. Neither melanin production nor tyrosinase activity induced by MSH, forskolin and 8-Br-cAMP were affected by KN-62 (calmodulin-dependent protein kinase II inhibitor), PD098059 (mitogen-activated protein kinase inhibitor, MAPKK) and worthmannin (phosphatidylinositol 3-kinase inhibitor). These results suggest that both protein kinase C and tyrosine kinase are involved in melanin production by cyclic AMP-dependent pathway and NFkB pathway may play an important role in cyclic AMP-dependent melanin production in B16 melanoma cells.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.205-211
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• 2007

This study was designed to investigate the suppressive effect of chlorophyll a on nitric oxide (NO) production and intracellular oxidative stress. In addition, chlorophyll a regulation of nuclear factor (NF) ${\kappa}B$ activation and inducible NO synthase (iNOS) expression were explored as potential mechanisms of NO suppression in a lipopolysaccharide (LPS)-stimulated macrophage cell line. RAW 264.7 murine macrophages were preincubated with various concentrations ($0-10\;{\mu}g/ mL$) of chlorophyll a and stimulated with LPS to induce oxidative stress and inflammatory response. Treatment with chlorophyll a reduced the accumulation of thiobarbituric acid-reactive substances (TBARS), enhancing glutathione level and the activities of antioxidative enzymes including superoxide dismutase, catalase, glutathione peroxidase (GSH-px), and glutathione reductase in LPS-stimulated macrophages compared to LPS-only treated cells. NO production was significantly suppressed in a dose-dependent manner (p<0.05) with an $IC_{50}$ of $12.8\;{\mu}g/mL$. Treatment with chlorophyll a suppressed the levels of iNOS protein and its mRNA expression. The specific DNA binding activities of NFkB on nuclear extracts from chlorophyll a treated cells were significantly suppressed in a dose-dependent manner with an $IC_{50}$ of $10.7\;{\mu}g/mL$. Chlorophyll a ameliorates NO production and iNOS expression through the down-regulation of NFkB activity, which may be mediated by attenuated oxidative stress in RAW 264.7 macrophages.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.75-75
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• 2003

Silica has been known to be a factor in acute cell injury and chronic pulmonary fibrosis. In Rat2 fibroblasts, silica induced the activation of NFkB, which plays a crucial role in regulating the expression of many genes involved in the subsequent inflammatory response. In addition, we observed that TAK1 and NIK were involved in silica-mediated NF-kB activation in Rat2 cells. (omitted)

• The Journal of Internal Korean Medicine
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• v.25 no.1
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• pp.59-70
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• 2004

Objectives : Previous studies showed that treatment with Chungganhaeju-tang prevents hepatic inflammation and apoptosis in alcoholic liver disease. The purpose of our study is to determine if any relations exsists between the transcription factor $NF{\kappa}B$, an orchestrating expression of a large number of genes and inhibitory effects of Chungganhaeju-tang on ethanol induced apoptosis. Materials and Methods : To assess the role of $NF{\kappa}B$, we blocked NFkB activation by delivering to the kupffer cells $I{\kappa}B{\Delta}N$, a dominant negative $NF{\kappa}B$ inhibitor, and investigated if Chungganhaeju-tang still prevented apoptosis. Results : When $NF{\kappa}B$ activation was blocked, there was no inhibitory effect of Chungganhaeju-tang on ethanol induced apoptosis of kupffer cells. Conclusion : This result suggests that Chungganhaeju-tang protects the liver from ethanol induced apoptosis by activating the $NF{\kappa}B$ that plays a key role in porotecting mechanism and reducing inflammatory cytokine gene expression.

• Proceedings of the SCSK Conference
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• 1996.07a
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• pp.10-14
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• 1996

최근 오존층의 파괴로 인한 지구 자외선량의 증가로 피부암 및 광노화의 발생가능성이 증가되고있다. 광노화의 주요한 현상중의 하나는 탄력섬유상 물질이 축적되는 일광탄력 섬유증이다. 자외선은 탄력소 유전자의 전사과정증가를 유도하며 결국 비정상적인 탄력소의 증가를 유발한다는 보고가 있다. 본 연구에서는 피부 섬유아세포 및 각질형성세포를 배양하여 자외선이 탄력소 유전자발현에 미치는 영향 및 전사조절인자에 미치는 영향을 알아보고자 하였다. 피부섬유아세포에 UVB를 30mJ-200J/m 조사하여 nothern blotting한 결과 UV양이 증가함에 따라 탄력소 전사물이 증가되었고, 1001/$m^2$ 에서 최대의 증가를 보였다. 탄력소 promoter와 CAT을 접합시킨 pEP62 vector을 섬유아세포에 형질전환 시키고 UV에 의한 Promoter 활성을 본 결과 UV조사량이 증가할수록 활성이 증가되었고 200J/$m^2$ 에서 대조군에 비해 5배의 활성 증가를 보였다. 이 system에 광노화 억제물질로 알려진 retinoid를 5 $\times$ $10^{-6}$M처리하였을 때 UV에 의한 탄력소 promoter활성을 약 1/3로 감소시켰다. 각질 형성세포에서 UVB에 의한 transcription factor의 활성을 mobility shift assay에 의해 조사한 결과 AP-1 및 NFkB가 활성화됨을 볼 수 있었다.

• Toxicological Research
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• v.17
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• pp.83-88
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• 2001

Most reactive oxygen species (ROS) are free radicals and implicated in the development of a number of disease processes including artherosclerosis, neurodegenerative disorders, aging and cancer. ROS are byproducts of a number of in vivo metabolic processes and are formed deliberately as part of nor-mal inflammatory response. On the other hand, ROS are generated either as by products of oxygen reduction during xenobiotic metabolism or are liberated as the result of the futile redox cycling of the chemical agents including several chemical carcinogens. A better understanding of the mechanisms of free radical toxicity may yield valuable clue to risks associated with chemical exposures that leading to the development of chronic diseases including cancer. The molecular biology of ROS-mediated alterations in gene expression, signal transduction and carcinognesis is one of the important subjects in free radical toxicology. Epidemiological studies suggest that high intake of vegetables and fruits are associated with the low incidence of human cancer. Many phytopolyphenols such as tea polyphenols, curcumin, resveratrol, apigenin, genistein and other flavonoids have been shown to be cancer chemopreventive agents. Most of these compounds are strong antioxidant and ROS scavengers in vitro and effective inducers of antioxidant enzymes such as superoxide dismutatse, catalase and glutathione peroxidase in vivo. Several cellular transducers namely receptor tyrosine kinase, protein kinase C, MAPK, PI3K, c-jun, c-fos, c-myc, NFkB, IkB kinase, iNOS, COX-2, Bcl-2, Bax, etc have been shown to be actively modulated by phyto-polyphenols. Recent development in free radical toxicology have provided strong basis for understanding the action mechanisms of cancer chemoprevention.