• BMB Reports
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• 제37권4호
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• pp.480-486
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• 2004

Brain ischemia brings about hypoxic insults. Hypoxia is one of the major pathological factors inducing neuronal injury and central nervous system infection. We studied the involvement of mitogen-activated protein (MAP) kinase in hypoxia-induced apoptosis using cobalt chloride in C6 glioma cells. In vitro cytotoxicity of cobalt chloride was tested by MTT assay. Its $IC_{50}$ value was $400\;{\mu}M$. The DNA fragment became evident after incubation of the cells with $300\;{\mu}M$ cobalt chloride for 24 h. We also evidenced nuclear cleavage with morphological changes of the cells undergoing apoptosis with electron microscopy. Next, we examined the signal pathway of cobalt chloride-induced apoptosis in C6 cells. The activation of extracellular signal-regulated protein kinase 1/2 (ERK 1/2) started to increase at 1 h and was activated further at 6 h after treatment of 400 M cobalt chloride. In addition, pretreatment of PD98059 inhibited cobalt chloride-induced apoptotic cell morphology in Electron Microscopy. These results suggest that cobalt chloride is able to induce the apoptotic activity in C6 glioma cells, and its apoptotic mechanism may be associated with signal transduction via MAP kinase (ERK 1/2).

• BMB Reports
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• 제42권3호
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• pp.148-153
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• 2009

Pyrrolidine dithiocarbamate (PDTC) is a stable anti-oxidant or pro-oxidant, depending on the situation, and it is widely used to inhibit the activation of NF-${\kappa}B$. We recently reported that PDTC activates the MIP-2 gene in a NF-${\kappa}B$-independent and c-Jun-dependent manner in macrophage cells. In this work, we found that PDTC activates signal transduction pathways in mouse ES cells. Among the three different mitogen-activated protein kinase (MAPK) pathways, including the extracellular-signal-regulated kinase (ERK), p38 MAP kinase, and stress-activated protein kinase (SAPK)/Jun N-terminal kinase (JNK) pathways, only the ERK pathway was significantly activated in mouse ES cells after stimulation with PDTC. Additionally, we observed a synergistic activation of ERK and induction of c-Fos after stimulation with PDTC in the presence of mouse embryonic fibroblast (MEF) conditioned medium. In contrast, another NF-${\kappa}B$ inhibitor, BMS-345541, did not activate the MAP kinase pathways or induce expression of c-Fos. These results suggest that changes in the presence of the NF-${\kappa}B$ inhibitor PDTC should be carefully considered when it used with mouse ES cells.

• 한국컴퓨터정보학회논문지
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• 제14권3호
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• pp.193-207
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• 2009

세포 내에서 일어나는 단백질 신호 전달 과정은 단백질간의 상호작용을 통해 수행되고 조절된다. Yeast 상호작용 정보와 녹색형광단백질(GFP)을 이용하여 밝혀진 약 5,000여 개의 Yeast 단백질 위치정보를 이용하여 가중치를 부여하고 신호 전달경로 추출 및 예측을 위한 고성능 LocSPF 알고리즘을 최초로 제안하였다. 가중치 알고리즘에 의해 산출된 결과 중 의미 상관도가 높은 것을 채택한 후 KEGG에서 제공하는 신호전달 경로와 같은 신호전달 경로를 추출하는지 유사도 비교를 하였다. 한편 더 나아가 아직 실험을 통해 밝혀지지 않은 단백질 신호전달 경로를 예측하여 결과를 제시함으로써 본 연구를 통해서 알려지지 않은 새로운 신호전달 경로를 발견하거나 이전 경로에 참여하지 않은 단백질들을 발견할 수 있는 가능성을 제시 하였다.

• 대한화장품학회지
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• 제28권1호
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• pp.31-41
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• 2002

The production of matrix matalloproteinases(MMPs) by the UV irradiated skin fibroblast and the degradation of extracellular matrix(ECM) by these enzymes is known as one of the main reasons of photoaging. Recently, Fisher group showed that the MMP expression is mainly regulated by the mitogen-activated protein(MAP) kinas family, such as extracellular signal-regulated kinase(ERK), c-Jun amino-terminal kinase(JNK) and p38, each of which forms a signaling pathway. In this work we first examined the effect of nitric oxide (NO) on the production of MMP-1 and MMP-2 by the human dermal fibroblasts (HDFs). NO is a multifunctional messenger molecule generated from L-arginine and involved in many kinds of signaling pathway. We found that the treatment of HDF with NO donor, sodium nitroprusside (SNP) enhanced the expression of MMPs with or without UV irradiation and the treatment with nitric oxide synthase (NOS) inhibitors resulted in the significant decrease of MMPs production. From these results, we concluded that the production of MMPs by the UV irradiated HDF is regulated through the signaling pathway involving NO and cyclic GMP.

• BMB Reports
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• 제39권5호
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• pp.469-478
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• 2006

Vascular endothelial growth factor (VEGF)-A, a major regulator for angiogenesis, binds and activates two tyrosine kinase receptors, VEGFR1 (Flt-1) and VEGFR2 (KDR/Flk-1). These receptors regulate physiological as well as pathological angiogenesis. VEGFR2 has strong tyrosine kinase activity, and transduces the major signals for angiogenesis. However, unlike other representative tyrosine kinase receptors which use the Ras pathway, VEGFR2 mostly uses the Phospholipase-$C{\gamma}$-Protein kinase-C pathway to activate MAP-kinase and DNA synthesis. VEGFR2 is a direct signal transducer for pathological angiogenesis including cancer and diabetic retinopathy, thus, VEGFR2 itself and the signaling appear to be critical targets for the suppression of these diseases. VEGFR1 plays dual role, a negative role in angiogenesis in the embryo most likely by trapping VEGF-A, and a positive role in adulthood in a tyrosine kinase-dependent manner. VEGFR1 is expressed not only in endothelial cells but also in macrophage-lineage cells, and promotes tumor growth, metastasis, and inflammation. Furthermore, a soluble form of VEGFR1 was found to be present at abnormally high levels in the serum of preeclampsia patients, and induces proteinurea and renal dysfunction. Therefore, VEGFR1 is also an important target in the treatment of human diseases. Recently, the VEGFR2-specific ligand VEGF-E (Orf-VEGF) was extensively characterized. Interestingly, the activation of VEGFR2 via VEGF-E in vivo results in a strong angiogenic response in mice with minor side effects such as inflammation compared with VEGF-A, suggesting VEGF-E to be a novel material for pro-angiogenic therapy.

• 대한치과교정학회지
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• 제33권3호
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• pp.199-210
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• 2003

치아이동 시 발생하는 골흡수에서 이미 여러 cytokine의 중요성이 강조된 바 있으며 이 가운데 interleukin-6는 구강 및 연골조직 등에서 많은 연구의 초점이 되어 왔으나 확실한 기전은 아직까지 정확히 확립되어 있지 못하다 골흡수 시 조골세포에서 유리되는 interleukin-6 (IL-6)와 nitric oxide (NO) 등이 골흡수의 조절자로 최근 대두되고 있으며 Mitogen-activated Protein kinase (MAPK)의 활성화로 인해 염증성 cytokine등이 유리될 수 있음이 최근 macrophage 등에서 증명된 바 있다. 그러므로 치아이동을 비롯한 구강 내 여러 염증의 조건에서 골흡수의 대표인자인 IL-6및 NO유리가 MAPK등의 활성 등을 통해 조절될 수 있는 가능성을 시사하고 있다. 본 연구에서 조골세포 특징을 대부분 가지고 있는 조골세포주 MC3T3El에서 p-38 MAP kinase을 매개로 NO와 IL-6가 유리됨을 확인하고자 하였다. $10\%$ Fetal Bovine Serum이 첨가된 -MEM 배양액으로 배양한 조골세포주인 MC3T3El 세포에 tumor necrosis $factor-\alpha(TNF-\alpha)$, $interferon-\gamma(IFN-\gamma)$ 및 lipopolysacchalide(LPS) 등의 단독처리 시 NO와 IL-6의 증가는 확인되지 않았으나 $TNF-\alpha/IFN-\gamma$ 혹은 $LPS/IFN-\gamma$ 등의 처치시 NO와 IL-6의 유의한 증가를 보였으며, NO발현에 직접 관여하는 inducible nitric oxide synthase (iNOS)와 IL-6 단백질 및 mRNA의 발현을 관찰하였다. 또한 specific p-38 MAP kinase inhibitor인 SB203580의 NO와 IL-6의 생성 억제를 관찰하고 단백질과 mRNA발현억제를 통해서도 확인함으로써 SB203580은 transcription 단계에서 NO와 IL-6의 생성을 조절하고 있음을 시사하여 주고 있다. $TNF-\alpha/IFN-\gamma$ 혹은 $LPS/IFN-\gamma$ 처치 시 p-38 MAP Kinase의 활성을 관찰하였으나 단독 처치 시 역시 P-38 MAP Kinase의 활성을 확인함으로써 NO와 IL-6생성기전에는 p-38 MAP Kinase이외에 다른 인자 역시 관여하고 있음을 보여주고 있다. 본 연구에서는 치아 등의 골조직의 구성 세포인 조골세포에서 NO와 IL-6유리를 확인하였으며, 또한 이들의 생성기전중의 하나로 p-38 MAP Kinase가 transcription 단계에서 관여하고 있음을 확인하였다.

• 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.

• Archives of Pharmacal Research
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• 제25권6호
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• pp.747-758
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• 2002

The skin displays a highly active metabolism of polyunsaturated fatty acids (PUFA). Dietary deficiency of linoleic acid (LA), an 18-carbon (n-6) PUFA, results in characteristic scaly skin disorder and excessive epidermal water loss. Although arachidonic acid (AA), a 20-carbon (n6) PUFA, is metabolized via cyclooxygenase pathway into predominantly prostaglandin $E_2(PGE_2)$ and $PGF_{2{\alpha}}$, the metabolism of AA via the 15-lipoxygenase (15-LOX) pathway, which is very active in skin epidermis and catalyzes the transformation of M into predominantly 15S-hydroxyeicosatetraenoic acid (15S-HETE). Additionally, the 15-LOX also metabolizes the 18-carbon LA into 13S-hydroxyoctadecadienoic acid (13S-HODE), respectively. Interestingly, 15-LOX catalyzes the transformation of $dihomo-{\gamma}-linolenic$ acid (DGLA), derived from dietary gamma-linolenic acid, to 15S-hydroxyeicosatrienoic acid (15S-HETrE). These monohydroxy fatty acids are incorporated into the membrane inositol phospholipids which undergo hydrolytic cleavage to yield substituted-diacylglycerols such as 13S-HODE-DAG from 13S-HODE and 15S-HETrE-DAG from 15S-HETrE. These substituted-monohydroxy fatty acids seemingly exert anti-inflammatory/antiproliferative effects via the modulation of selective protein kinase C as well as on the upstream/down-stream nuclear MAP-kinase/AP-1/apoptotic signaling events.

• Mycobiology
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• 제38권4호
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• pp.302-309
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• 2010

Formic acid is a representative carboxylic acid that inhibits bacterial cell growth, and thus it is generally considered to constitute an obstacle to the reuse of renewable biomass. In this study, Saccharomyces cerevisiae was used to elucidate changes in protein levels in response to formic acid. Fifty-seven differentially expressed proteins in response to formic acid toxicity in S. cerevisiae were identified by 1D-PAGE and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analyses. Among the 28 proteins increased in expression, four were involved in the MAP kinase signal transduction pathway and one in the oxidative stress-induced pathway. A dramatic increase was observed in the number of ion transporters related to maintenance of acid-base balance. Regarding the 29 proteins decreased in expression, they were found to participate in transcription during cell division. Heat shock protein 70, glutathione reductase, and cytochrome c oxidase were measured by LC-MS/MS analysis. Taken together, the inhibitory action of formic acid on S. cerevisiae cells might disrupt the acidbase balance across the cell membrane and generate oxidative stress, leading to repressed cell division and death. S. cerevisiae also induced expression of ion transporters, which may be required to maintain the acid-base balance when yeast cells are exposed to high concentrations of formic acid in growth medium.

• Archives of Pharmacal Research
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• 제26권12호
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• pp.1055-1060
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• 2003

Lysophosphatidic acid (LPA) is a well-known mitogen in various cell types. However, we found that LPA inhibits melanocyte proliferation. Thus, we further investigated the possible signaling pathways involved in melanocyte growth inhibition. We first examined the regulation of the three major subfamilies of mitogen-activated protein (MAP) kinases and of the Akt pathway by LPA. The activations of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) were observed in concert with the inhibition of melanocyte proliferation by LPA, whereas p38 MAP kinase and Akt were not influenced by LPA. However, the specific inhibition of the ERK or JNK pathways by PD98059 or D-JNKI1, respectively, did not restore the antiproliferative effect. We next examined changes in the expression of cell cycle related proteins. LPA decreased cyclin $D_1 and cyclin D_2$ levels but increased $p21^{WAF1/CIP1}$ (p21) and $p27^{KIP1}$ (p27) levels, which are known inhibitors of cyclin-dependent kinase. Flow cytometric analysis showed the inhibition of DNA synthesis by a reduction in the S phase and an increase in the $G_0/G_1$ phase of the cell cycle. Our results suggest that LPA induces cell cycle arrest by regulating the expressions of cell cycle related proteins.