• Archives of Pharmacal Research
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• 제26권11호
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• pp.937-942
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• 2003

Nitric oxide(NO) induces apoptosis in human osteoblasts. Treatment with exogenous NO donors, SNAP (S-Nitroso-N-acelylpenicillamine) and SNP (sodium nitroprusside), to MG-63 osteoblasts resulted in apoptotic morphological changes, as shown by a bright blue-fluorescent condensed nuclei and chromatin fragmentation by fluorescence microscope of Hoechst 33258-staining. The activities of caspase-9 and the subsequent caspase-3-like cysteine proteases were increased during NO-induced cell death. Pretreatment with Z-VAD-FMK (a pancaspase inhibitor) or Ac-DEVD-CHO (a specific caspase-3 inhibitor) abrogated the NO-induced cell death. The NO donor markedly activated JNK, a stress-activated protein kinase in the human osteoblasts. This study showed that the inhibition of the JNK pathway markedly reduced NO-induced cell death. But neither PD98059 (MEK inhibitor) nor SB203580 (p38 MAPK inhibitor) had any effect on NO-induced death. Taken together, these results suggest that JNK/SAPK may be related to NO-induced apoptosis in MG-63 human osteoblasts.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1170-1178
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• 2008

The cyclopentenone prostaglandins (cyPGs) prostaglandin $A_1$ ($PGA_1$) and 15-deoxy-${\Delta}^{12,14}$-prostaglandin $J_2$ (15d-$PGJ_2$) have been reported to exhibit antiinflammatory activity in activated monocytes/macrophages. However, the effects of these two cyPGs on the expression of cytokine genes may differ. In this study, we investigated the mechanism of action of $PGA_1$ in lipopolysaccharide (LPS)-induced expression of inter leu kin (IL)-10 mRNA in mouse peritoneal macrophages. 15d-$PGJ_2$ inhibited expression of LPS-induced IL-10, whereas $PGA_1$ increased LPS-induced IL-10 expression. This synergistic effect of $PGA_1$ on LPS-induced IL-10 expression reached a maximum as early as 2 h after simultaneous $PGA_1$ and LPS treatment ($PGA_1$/LPS), and did not require new protein synthesis. The synergistic effect of $PGA_1$ was inhibited by GW9662, a specific peroxisome proliferator-activated receptor ${\gamma}(PPAR{\gamma})$ antagonist, and Bay-11-7082, a NF-${\kappa}B$ inhibitor. The extracellular signal-regulated kinases (ERK) inhibitor PD98059 increased the expression of $PGA_1$/LPS-induced IL-10 mRNA, rather than inhibiting the IL-10 expression. Moreover, $PGA_1$ inhibited LPS-induced ERK phosphorylation. The synergistic effect of $PGA_1$ on LPS-induced IL-10 mRNA and protein production was inhibited by p38 inhibitor PD169316, and $PGA_1$ increased LPS-induced p38 phosphorylation. In the case of stress-activated protein kinase/c-Jun $NH_2$-terminal kinase (SAPK/JNK), the SAPK/JNK inhibitor SP600125 did not inhibit IL-10 mRNA synthesis but inhibited the production of IL-10 protein remarkably. These results suggest that the synergistic effect of $PGA_1$ on LPS-induced IL-10 expression is NF-${\kappa}B$-dependent and mediated by mitogen-activated protein (MAP) kinases, p38, and SAPK/JNK signaling pathways, and also associated with the $PPAR{\gamma}$ pathway. Our data may provide more insight into the diverse mechanisms of $PGA_1$ effects on the expression of cytokine genes.

• The Korean Journal of Physiology and Pharmacology
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• 제8권6호
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• pp.339-344
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• 2004

Recent data have shown the importance of oxidative stresses in the pathogenesis of inflammatory bowel disease, crohn's disease and ulcerative colitis. $H_2O_2$, reactive oxygen species (ROS) donor, has been reported to act as a signaling molecule involved in a variety of cellular functions such as apo/ptosis and proliferation. In the present study, we investigated viability of cultured ileal smooth muscle cells (ISMC) after stimulation with $H_2O_2$. Trypan blue method revealed that the cell viability of ISMC treated with 1 mM $H_2O_2$ was not different from that of controls at up to 2 h time point, while treatment of ISMC with 1 mM $H_2O_2$ for 48 h finally induced significant decrease in the cell viability. Therefore, we evaluated whether $H_2O_2$ was capable of ERKs activation in ISMC for the short-term exposure and examined whether tyrosine kinase was involved in the process of ERK activation by $H_2O_2$ in ISMC. We also investigated the effects of $H_2O_2$ on activation of SAPK/JNK and p38 MAP kinase in ISMC. Thus, ISMC were cultured and exposed to $H_2O_2$, and western blot analysis was performed with phosphospecific MAP kinase antibodies. Robust activation of ERK occurred within 30 min of 1 mM $H_2O_2$ treatment. $H_2O_2-induced$ ERK activation was attenuated by a tyrosine kinase inhibitor, genistein, indicating that tyrosine kinase was probably involved in the ERK activation by $H_2O_2$. $H_2O_2$ was a moderate activator of SAPK/JNK, while p38 MAP kinase was not activated by $H_2O_2$. We suggest that ERK activation induced by short-term $H_2O_2$ treatment plays a critical role in cellular protection in the early stage of response to oxidative stress. The present study suggests the necessity of identification of MAPK signaling pathways affected by ROS, since it could ultimately elucidate cellular consequences involved in initiation and perpetuation of intestinal tissue damage in the diseases such as crohn's disease and ulcerative colitis, resulted from excessive ROS.

• Molecules and Cells
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• 제24권1호
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• pp.95-104
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• 2007

The mechanism of acacetin-induced apoptosis of human breast cancer MCF-7 cells was investigated. Acacetin caused 50% growth inhibition ($IC_{50}$) of MCF-7 cells at $26.4{\pm}0.7{\mu}M$ over 24 h in the MTT assay. Apoptosis was characterized by DNA fragmentation and an increase of sub-G1 cells and involved activation of caspase-7 and PARP (poly-ADP-ribose polymerase). Maximum caspase 7 activity was observed with $100{\mu}M$ acacetin for 24 h. Caspase 8 and 9 activation cascades mediated the activation of caspase 7. Acacetin caused a reduction of Bcl-2 expression leading to an increase of the Bax:Bcl-2 ratio. It also caused a loss of mitochondrial membrane potential that induced release of cytochrome c and apoptosis inducing factor (AIF) into the cytoplasm, enhancing ROS generation and subsequently resulting in apoptosis. Pretreatment of cells with N-acetylcysteine (NAC) reduced ROS generation and cell growth inhibition, and pretreatment with NAC or a caspase 8 inhibitor (Z-IETD-FMK) inhibited the acacetin-induced loss of mitochondrial membrane potential and release of cytochrome c and AIF. Stress-activated protein kinase/c-Jun $NH_4$-terminal kinase 1/2 (SAPK/JNK1/2) and c-Jun were activated by acacetin but extracellular-regulated kinase 1/2 (Erk1/2) nor p38 mitogen-activated protein kinase (MAPK) were not. Our results show that acacetin-induced apoptosis of MCF-7 cells is mediated by caspase activation cascades, ROS generation, mitochondria-mediated cell death signaling and the SAPK/JNK1/2-c-Jun signaling pathway, activated by acacetin-induced ROS generation.

• The Korean Journal of Physiology and Pharmacology
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• 제7권4호
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• pp.199-205
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• 2003

Osteoblasts are affected by TNF-${\alpha}$ overproduction by immune cells during inflammation. It has been suggested that functional $NF-{\kappa}B$ sites are involved in TNF-${\alpha}$-induced bone resorption. Thus, we explored the effect of pyrrolidine dithiocarbamate (PDTC), which potently blocks the activation of nuclear factor $(NF-{\kappa}B)$, on the induction of TNF-${\alpha}$-induced activation of JNK/SAPK, AP-1, cytochrome c, caspase and apoptosis in MC3T3E1 osteoblasts. Pretreatment of the cells with PDTC blocked TNF-${\alpha}$-induced $NF-{\kappa}B$ activation. TNF-${\alpha}$-induced activation of AP-1, another nuclear transcription factor, was suppressed by PDTC. The activation of c-Jun N-terminal kinase, implicated in the regulation of AP-1, was also down regulated by PDTC. TNF-${\alpha}$-induced apoptosis, release of cytochrome c and subsequent activation of caspase-3 were abolished by PDTC. TNF-${\alpha}$-induced apoptosis was partially blocked by Ac-DEVD-CHO, a caspase-3 inhibitor, suggesting that caspase-3 is involved in TNF-${\alpha}$-mediated signaling through $NF-{\kappa}B$ in MC3T3E1 osteoblasts. Thus, these results demonstrate that PDTC, has an inhibitory effect on TNF-${\alpha}$-mediated activation of JNK/SAPK, AP-1, cytochrome c release and subsequent caspase-3, leading to the inhibition of apoptosis. Our study may contribute to the treatment of TNF-${\alpha}$-associated immune and inflammatory diseases such as rheumatoid arthritis and periodontal diseases.

• 대한물리치료과학회지
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• 제10권2호
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• pp.199-207
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• 2003

The present study examined that in vivo/vitro test is investigated in normotensive sham-operated rats(NSR) and aldosterone-analogue deoxycorticosterone acetate (DOCA)-salt hypertensive rats(ADHR) and that the antiliypertensive effect was induced by silver spike point(SSP) electrical stimulation at meridian points(CV-3, -4, Ki-12, SP-6, LR-3, BL-25, -28, -32, -52), specifically, such as aldosterone in 24 hour urine analysis from normal volunteer. The heart weight, the tickness of vascular wall, collagen fiber and the systolic blood pressure were significantly increased in ADHR than that in NSR. The required time of PSS-induced resting tone and the phosphorylation of stress-activated protein kinase/c-Jun N-terminal protein kinase(SAPK/JNK) were significantly increased in ADHR than that in NSR. However, the Kv currents were significantly decreased in ADHR than that in NSR. The current of 1 Hz continue type of SSP electrical stimulation significantly decreased in excretion of urine aldosterone from normal volunteer. These results suggest that the development of aldosterone analogue-induced hypertension is associated with changed heart weight, content of collagen fiber, tickness of vascular wall, blood pressure, resting tone, voltage-dependent K+ current(Kv) and phosphorylation of SAPK/JNK, which directly affects blood pressure. Therefore the hypertension is a risk factor on cerebrovascular disease. Moreover, These results suggest that the SSP electrical stimulation, especially current of 1 Hz continue type, significantly regulates excretion of urine aldosterone from volunteer.

• Archives of Pharmacal Research
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• 제28권8호
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• pp.942-947
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• 2005

Peroxynitrite is a potent neurotoxic molecule produced from a reaction between NO and super-oxide and induces NO-mediated inflammation under neuropathological conditions. Previously, we reported that glucose deprivation induced ATP depletion and cell death in immunostimulated astrocytes, which was mainly due to peroxynitrite. In this study, the role of MAPKs (ERK1/2, p38MAPK, and JNK/SAPK) signal pathway in the SIN-1/glucose deprivation-induced death of astrocytes was examined. A combined treatment with glucose deprivation and $50 {\mu}M$ SIN-1, an endogenous peroxynitrite generator, rapidly and markedly increased the death in rat primary astrocytes. Also, SIN-1/glucose deprivation resulted in the activation of MAPKs, which was significantly blocked by the treatment with $20{\mu}M$ MAPKs inhibitors (ERK1/2, PD98059; p38MAPK, SB203580; JNK/SAPK, SP600125). Interestingly, SIN-1/glucose deprivation caused the loss of intracellular ATP level, which was significantly reversed by MAPKs inhibitors. These results suggest that the activation of MAPKs plays an important role in SIN-1/glucose deprivation-induced cell death by regulating the intracellular ATP level.

• 대한한의학회지
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• 제39권4호
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• pp.158-170
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• 2018

Objectives: The objective of this study is Korean mistletoe lectin (Viscum album coloratum agglutinin, VCA) and bee venom (BV) to experimental prove comparative study of VCA and BV on the anti-cancer effect and mechanisms of action. Methods: In this study, it was examined in a human hepatocellular carcinoma cell line, Hep G2 cells. Cytotoxic effects of VCA and BV on Hep G2 cells were determined by 3- (4, 5-dimethylthiazol-2-yl) -2, 5-diphenyltetrazolium bromide (MTT) assay in vitro. VCA and BV killed Hep G2 cells in a time- and dose-dependent manner. Results: The apoptotic cell death was then confirmed by propidium iodide staining and DNA fragmentation analysis. The mechanisms of action was examined by the expression of anti-apoptotic proteins and activation of mitogen-activated protein kinases. Treatment of Hep G2 cells with VCA activated poly (ADP-ribose) polymerase-1 (PARP-1) known as a marker of apoptosis, and mitogen-activated protein kinases signaling pathways including SAPK/JNK, MAPK and p38. BV also activated PARP-1, MAPK, p38 but not JNK. The expression level of anti-apoptotic molecule, Bcl-X, was decreased by VCA treatment but not BV. Finally, the phosphorylation level of ERM proteins involved in the cytoskeleton homeostasis was decreased by both stimuli. Conclusion: We examined the involvement of kinase in VCA or BV - induced apoptosis by using kinase inhibitors. VCA-induced apoptosis was partially inhibited by in the presence.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.242.1-242.1
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• 2002

H$_2$O$_2$ has been shown to act as a signaling molecule involved in many cellular functions such as oxidant-induced stress, apoptosis, proliferation. In this study, we investigated the action mechanisms of H$_2$O$_2$ on activation of Extracellular Signal-Regulated Protein Kinase(ERK) in cultured feline ileal smooth muscle cells(ISMC). Western blot analysis done with phospho-specific MAP kinases antibodies demonstrated that potent activation of ERK and moderate activation of SAPK/JNK occurred within 30 min of H$_2$O$_2$ treatment. (omitted)

• 한국식품영양과학회지
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• 제41권9호
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• pp.1226-1234
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• 2012

본 연구에서는 염증반응을 조절하는 다양한 신호전달체계를 중심으로 분자생물학적 방법을 통해 piceatannol의 항염증 기전을 규명하였다. LPS로 염증반응을 유도한 Raw 264.7 대식세포에서 piceatannol은 iNOS의 발현 억제를 통해 NO의 생성을 감소시키고 염증성 사이토카인(TNF-${\alpha}$, IL-6, IL-$1{\beta}$)의 생성을 감소시켰다. 염증반응을 조절하는 신호전달체계 중 piceatannol은 LPS에 의해 유도된 $I{\kappa}B$의 분해와 p65의 핵으로의 이동을 억제하고, LPS에 의해 유도된 SAPK/JNK의 인산화를 억제하였다. 또한 piceatannol은 LPS와 IL-6(LPS에 의해 증가됨)에 의한 STAT3의 활성화를 억제하였다. 뿐만 아니라 piceatannol은 Nrf2의 핵 내 축적을 야기하고 ARE의 transcriptional activity를 증가시켜 HO-1의 발현을 증가시켰다. 본 연구의 결과, piceatannol은 NF-${\kappa}B$와 AP-1, STAT3 신호전달의 억제를 통해, 그리고 HO-1의 발현 증가를 통해 항염증 효과를 나타내었다(Fig. 8).