• Clinical and Experimental Reproductive Medicine
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• 제28권2호
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• pp.111-120
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• 2001

Objective: To verify the expression of leptin receptor (OB-R) in oocytes and preimplantation embryos, the involvement of mitogen activated protein kinase (MAPK or Erk1/2) in the leptin signaling, and effect of leptin on the oocyte maturation in mice. Method: RT-PCR analysis of OB-R was conducted in germinal vesicle (GV)-intact and MII stage oocytes, and 1, 2, 8-cell embryos and blastocysts. Germinal vesicle breakdown (GVB), polar body extrusion, monitored in the presence or absence of leptin ($1{\mu}M$). Following the leptin treatment, temporal changes in MAPK activity were verified by immunoprecipitation and in vitro kinase assay in MII oocytes. Results: The expression of OB-R mRNA was found in GV and MII oocyte but not in the embryos. MAPK activity of the MII oocytes was significantly increased by brief incubation in the HTF supplemented with leptin ($1{\mu}M$). Priming of PD098059, a MEK inhibitor to leptin treatment attenuated the activation of MAPK by leptin in MII oocytes. Following 24 hrs of culture of the GV oocytes, leptin significant increased the GVB and 1 st polar body extrusion. Conclusion: This result suggested that functional interaction between leptin and OB-R resulted in potentiation of MAPK (Erk1/2) activity in MII oocytes through MEK activation and that leptin might be a local regulator of meiotic maturation of the mouse oocytes.

• Journal of Life Science
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• 제16권7호
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• pp.1229-1234
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• 2006

This study investigated whether matrix metalloproteinases (MMPs) can be modified in apoptotic smooth muscle cell (SMC) using the SMC that undergoes apoptotic death by expressing Fas-associated death domain containing protein (FADD) when they are grown without tetracycline in culture medium. In the absence of tetracycline, FADD-SMC lost adherence and showed the fragmentation of the nuclei. In proportion to duration of tetracycline removal, phosphorylated form of p38 MAPK and of ERK increased, whereas phosphorylation of protein kinase B (PKB) was not changed very much in response to tetracycline The levels of cyclin A and cyclin D were also decreased in a time dependent manner. Up-regulation of MMP-9 expression and activity was observed when the SMC were grown without tetracycline. Immunoreactivity of MMP-9 was detected from both attached and floating FADD-SMCs grown without tetracycline. An inhibitor of MAPK kinase, PD098059, and an inhibitor of p38 MAPK, SB203580, inhibited the up-regulation of MMP-9. Treatment of the SMC with a synthetic MMP inhibitor, BB94, attenuated death occurring in the absence of tetracycline. These results indicate that SMC undergoing death is able to up-regulate MMP-9 and that the enzyme can affect cell viability.

• Korean Journal of Pharmacognosy
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• 제44권3호
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• pp.269-274
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• 2013

In this study, we investigated the anticancer effect of rice bran extract in HL-60 human promyelocytic leukemia cells. The extract of rice bran inhibited the proliferation of HL-60 cells. When treated with the rice bran extract, we could observe the apoptotic characteristics such as apoptotic bodies and the increase of sub-G1 hypodiploid cell population, increase of Bax level, decrease of Bcl-2 expression, cleavage of procaspase-3, cleavage of procaspase-9 and cleavage of poly(ADP-ribose) polymerase(PARP) in HL-60 cells. Furthermore, the apoptosis induction of HL-60 cells treated with the rice bran extract was also accompanied by the inactivation of mitogen-activated protein kinases (MAPK) such as ERK1/2 MAPK and p38 MAPK. In addition, the rice bran extract induced the down-regulation of c-myc. These data suggested that the rice bran extract could induce the apoptosis via the inactivation of ERK1/2 MAPK and p38 MAPK, and the down-regulation of c-myc in HL-60 acute pomyelocytic leukemia cells. The results support that the rice bran extract might have potential for the treatment of acute promyelocytic leukemia.

• The Korea Journal of Herbology
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• 제37권6호
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• pp.19-28
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• 2022

Objectives : To develop natural ingredients that help prevent or treat anti-inflammatory-related diseases and use themas basic data, we investigated anti-inflammatory activity of Cynanchi Atrati Radix Et Rhizoma water extracts(CWE) in lipopolysaccharide(LPS)-induced murine macrophage cell line, RAW 264.7 cells. Methods : The cell viabilities were evaluated with RAW 264.7 cells. The production of nitric oxide(NO), prostaglandin E2(PGE2), pro-inflammatory cytokines such tumor necrotic factor(TNF)-α and interleukin(IL)-6 were assessed in LPS-induced RAW 264.7 cell treated with CWE. Furthermore, the protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2(COX-2), and mitogen-activated protein kinase(MAPK) were assessed by western blotting. Results : In RAW 264.7 cell, the cell viability by CWE treatment was more than 98.4% at a concentration of 100-400 ㎍/mL. At a concentration of 800 ug/ml of CWE, the cell viability was as low as 86%. At doses of 100, 200 and 400 ㎍/mL, CWE inhibited the production of NO, PGE2, TNF-𝛼 and IL-6 in a dose-dependent manner and also decreased the expression of iNOS and COX-2 from LPS-induced RAW 264.7 cells. In addition, CWE significantly inhibited the MAPK pathway including decreased the phosphorylation of the p38, c-Jun N-terminal kinase(JNK) and extracellular signal-regulated kinase(ERK1/2). Conclusions : Our study provides evidence that CWE inhibits the production of main pro-inflammatory molecules in LPS-induced RAW 264.7 cells via expression of p38, JNK, and ERK1/2 MAPK signaling pathways. Therefore, CWE is expected to be widely used as a natural ingredient for anti-inflammatory functional foods or pharmaceuticals in the future.

• Biomolecules & Therapeutics
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• 제22권6호
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• pp.503-509
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• 2014

Paraquat has been suggested to induce apoptosis by generation of reactive oxygen species (ROS). However, little is known about the mechanism of paraquat-induced apoptosis. Here, we demonstrate that extracellular signal-regulated protein kinase (ERK) is required for paraquat-induced apoptosis in NIH3T3 cells. Paraquat treatment resulted in activation of ERK, and U0126, inhibitors of the MEK/ERK signaling pathway, prevented apoptosis. Moreover, paraquat-induced apoptosis was associated with cytochrome C release, which could be prevented by treatment with the MEK inhibitors. Taken together, our findings suggest that ERK activation plays an active role in mediating paraquat-induced apoptosis of NIH3T3 cells.

• Parasites, Hosts and Diseases
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• 제55권6호
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• pp.613-622
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• 2017

IL-12 and IL-23 are closely related in structure, and have been shown to play crucial roles in regulation of immune responses. However, little is known about the regulation of these cytokines in T cells. Here, we investigated the roles of PI3K and MAPK pathways in IL-12 and IL-23 production in human Jurkat T cells in response to Toxoplasma gondii and LPS. IL-12 and IL-23 production was significantly increased in T cells after stimulation with T. gondii or LPS. T. gondii and LPS increased the phosphorylation of AKT, ERK1/2, p38 MAPK, and JNK1/2 in T cells from 10 min post-stimulation, and peaked at 30-60 min. Inhibition of the PI3K pathway reduced IL-12 and IL-23 production in T. gondii-infected cells, but increased in LPS-stimulated cells. IL-12 and IL-23 production was significantly reduced by ERK1/2 and p38 MAPK inhibitors in T. gondii- and LPS-stimulated cells, but not in cells treated with a JNK1/2 inhibitor. Collectively, IL-12 and IL-23 production was positively regulated by PI3K and JNK1/2 in T. gondii-infected Jurkat cells, but negatively regulated in LPS-stimulated cells. And ERK1/2 and p38 MAPK positively regulated IL-12 and IL-23 production in Jurkat T cells. These data indicate that T. gondii and LPS induced IL-12 and IL-23 production in Jurkat T cells through the regulation of the PI3K and MAPK pathways; however, the mechanism underlying the stimulation of IL-12 and IL-23 production by T. gondii in Jurkat T cells is different from that of LPS.

• Journal of Veterinary Clinics
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• 제30권5호
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• pp.339-345
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• 2013

Mitogen-activated protein kinases (MAPKs) are a family of central signaling molecules that respond to numerous stimuli and are known to participate in processes of cell survival and death. However, it is not clear on data for cell-type specific activation of MAPKs in the progression of gastric ulcer. In the present study, we assessed how MAPKs localized at various cell types during the progression of gastric ulcer induced by ibuprofen. Gastric ulcer was induced by the repeated treatment of 200 mg/kg ibuprofen with 8 hrs interval in a day. Animals were sacrificed at 24 hrs, 48 hrs, and 72 hrs after oral treatment of ibuprofen and gastric tissues were subjected to immunohistochemical and immunoblotting evaluation. Immunoreactivity of phospho-extracellular signal-regulated kinase (p-ERK) was mainly expressed at the proliferating zone of gastric mucosa in control rats. But, these signals for p-ERK were highly shifted from cells of proliferating zone to parietal cells of the basal regions 24 hrs after treatment of ibuprofen. p-ERK signal was strongly expressed in epithelial cells adjacent to ulcer margin and new capillary and infiltrated inflammatory cells within granulation tissue of the ulcer base above 48 hrs after treatment of ibuprofen. While, phospho-c-Jun $NH_2$ terminal kinase (p-JNK) was mainly localized to the nuclei of the surface epithelial cells and the glandular epithelial cells in early gastric injury. Also, p-JNK was often observed as a scattered pattern in different regions of gastric mucosa with early gastric injury. Gradually, signal of p-JNK was strongly stained in infiltrated inflammatory cells and fibroblasts within severe ulcer base. Phospho-p38 (p-p38) MAPK was observed as scattered pattern within connective tissues of gastric mucosa. Especially, p-p38 MAPK showed strong signal in infiltrated macrophages within ulcer base. These results show that each MAPK has a specific role in various cell types during the progression of gastric ulcer.

• The Korea Journal of Herbology
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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.

• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.389-396
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• 2009

Objective : Triptolide (TP) has been reported to suppress the expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1), of which main function is to inactivate the extracellular signal-regulated kinase-1/2 (ERK-1/2), the p38 MAPK and the c-Jun N-terminal kinase-1/2 (JNK-1/2), and to exert antiproliferative and pro-apoptotic activities. However, the mechanisms underlying antiproliferative and pro-apoptotic activities of TP are not fully understood. The purpose of this study was to examine whether the down-regulation of MKP-1 expression by TP would account for antiproliferative activity of TP in immortalized HT22 hippocampal cells. Methods : MKP-1 expression and MAPK phosphorylation were analyzed by Western blot. Cell proliferation was assessed by $^3H$-thymidine incorporation. Small interfering RNA (siRNA) against MKP-1, vanadate (a phosphatase inhibitor), U0126 (a specific inhibitor for ERK-1/2), SB203580 (a specific inhibitor for p38 MAPK), and SP600125 (a specific inhibitor for JNK-1/2) were employed to evaluate a possible mechanism of antiproliferative action of TP. Results : At its non-cytotoxic dose, TP suppressed MKP-1 expression, reduced cell growth, and induced persistent ERK-1/2 activation. Similar growth inhibition and ERK-1/2 activation were observed when MKP-1 expression was blocked by MKP-1 siRNA and its activity was inhibited by vanadate. The antiproliferative effects of TP, MKP-1 siRNA, and vanadate were significantly abolished by U0126, but not by SB203580 or SP600125. Conclusion : Our findings suggest that TP inhibits the growth of immortalized HT22 hippocampal cells via persistent ERK-1/2 activation by suppressing MKP-1 expression. Additionally, this study provides evidence supporting that MKP-1 may play an important role in regulation of neuronal cell growth.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 한국발생생물학회 2001년도 후기 제12차 학술대회 논문집
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• pp.45-47
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• 2001

생쥐 착상전 초기배아에서 insulin과 tumor necrosis factor $\alpha$ (TNF$\alpha$)에 의한 배아의 형태 발생, 세포증식, apoptosis 및 MAPK활성의 변화를 조사하였다. Insulin에 의해 형태발생 및 포배당 세포수가 증가되었으며 TNF $\alpha$ 처리시 유의하게 감소하였다. TNT$\alpha$ 전처리시 insulin에 의한 발생 및 세포수 증가 촉진효과가 상쇄되었으며 TNF$\alpha$는 배아내 caspase-3의 활성을 증가시켰다. Insulin은 단시간내에 포배에서 mitogen activated protein kinase (MAPK or Erk1/2)의 활성을 증가시켰다. TNF$\alpha$는 포배내 MAPK의 활성을 감소시켰다. Insulin 처리 전 TNF $\alpha$를 전처리한 경우 insulin에 의한 MAPK 활성의 증가가 상쇄되었다. 배발생을 촉진하는 인슐린 신호전달 과정은 MAPK cascade를 경유하며 TNF $\alpha$를 경유한 신호전달과 Crosstalk이 존재하는 것으로 사료된다.