• BMB Reports
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• 제50권1호
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• pp.31-36
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• 2017

High-dose caffeine uptake is a developmental stressor and causes food-avoidance behavior (aversion phenotype) in C. elegans, but its mode of action is largely unknown. In this study, we investigated the molecular basis of the caffeine-induced aversion behavior in C. elegans. We found that aversion phenotype induced by 30 mM caffeine was mediated by JNK/MAPK pathway, serotonergic and dopaminergic neuroendocrine signals. In this process, the dopaminergic signaling appears to be the major pathway because the reduced aversion behavior in cat-2 mutants and mutants of JNK/MAPK pathway genes was significantly recovered by pretreatment with dopamine. RNAi depletion of hsp-16.2, a cytosolic chaperone, and cyp-35A family reduced the aversion phenotype, which was further reduced in cat-2 mutants, suggesting that dopaminergic signal is indeed dominantly required for the caffeine-induced food aversion. Our findings suggest that aversion behavior is a defense mechanism for worms to survive under the high-dose caffeine conditions.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2022년도 추계학술대회
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• pp.93-93
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• 2022

Hovenia dulcis, one of the traditional medicinal plants, is currently being used as a functional ingredient for the development of health functional foods that protects the liver from alcohol damage in Korea. A variety of pharmacological effects of Hovenia dulcis have been reported so far, but studies on immune-enhancing activity are insufficient. Thus, in this study, we report that Hovenia dulcis branches (HDB) induce the activation of macrophages. HDB increased the production of immunostimulatory factors and phagocytosis in RAW264.7 cells. TLR4 inhibition blocked HDB-mediated production of immunostimulatory factors. In addition, the JNK inhibition reduced the HDB-mediated production of immunostimulatory factors, and the HDB-mediated JNK activation was blocked by the TLR4 inhibition. HDB increased the level of LC3-II and p62/SQSTM1. TLR4 inhibition blocked HDB-mediated increase in the level of LC3-II and p62/SQSTM1. These findings indicate that HDB may induce TLR4/JNK-dependent macrophage activation and TLR4-dependent macrophage autophagy.

• 치위생과학회지
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• 제10권4호
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• pp.227-231
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• 2010

The purpose of this study was to examine the MAPK signaling pathways involved in regulation of HO-1 and the odontoblast differentiation markers during the odontoblastic differentiation for HDPCs. We evaluated cell growth by MTT assay and differentiation marker mRNA expression by RT-PCR. When the cells were treated with p38 inhibitor (SB203580, $10{\mu}M$), JNK inhibitor (SP600125, $10{\mu}M$), and ERK inhibitor (PD98059, $20{\mu}M$) for 7 days, cell growth and expression of HO-1 and differentiation makers were significantly decreased in HDPCs. Our results suggest that odontoblastic differentiation is positively regulated by HO-1 induction in HDPCs via ERK, JNK, and p38 signaling pathways. Thus, pharmacological HO-1 induction might represent a potent therapeutic approach for pulp capping and the regeneration of HDPCs.

• BMB Reports
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• 제35권4호
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• pp.371-376
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• 2002

The receptor activator of nuclear factor kappa B (RANK) is a member of the tumor necrosis factor (TNF) receptor superfamily. It plays a critical role in osteoclast differentiaion, lymph node organogenesis, and mammary gland development. The stimulation of RANK causes the activation of transcription factors NF-${\kappa}B$ and activator protein 1 (AP1), and the mitogen activated protein kinase (MAPK) c-Jun N-terminal kinase (JNK). In the signal transduction of RANK, the recruitment of the adaptor molecules, TNF receptor-associated factors (TRAFs), is and initial cytoplasmic event. Recently, the association of the MAPK kinase kinase, transforming growth factor-$\beta$-activated kinase 1 (TAK1), with TRAF6 was shown to mediate the IL-1 signaling to NF-${\kappa}B$ and JNK. We investigated whether or not TAK1 plays a role in RANK signaling. A dominant-negative form of TAK1 was discovered to abolish the RANK-induced activation of AP1 and JNK. The AP1 activation by TRAF2, TRAF5, and TRAF6 was also greatly suppressed by the dominant-negative TAK1. the inhibitory effect of the TAK1 mutant on RANK-and TRAF-induced NF-${\kappa}B$ activation was also observed, but less efficiently. Our findings indicate that TAK1 is involved in the MAPK cascade and NF-${\kappa}B$ pathway that is activated by RANK.

• Biomolecules & Therapeutics
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• 제20권1호
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• pp.57-61
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• 2012

The matrix metalloproteinase (MMP) family is involved in the breakdown of the extracellular matrix during normal physiological processes such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes such as pathological aging, arthritis, and metastasis. Oxidative conditions generate reactive oxygen species (ROS) (e.g., hydrogen peroxide [$H_2O_2$]) in cells, which subsequently induce the synthesis of matrix metalloproteinase-1 (MMP-1). MMP-1, an interstitial collagenase, in turn stimulates an aging phenomenon. In this study, baicalein (5,6,7-trihydroxyfl avone) was investigated for its in vitro activity against $H_2O_2$-induced damage using a human skin keratinocyte model. Baicalein pretreatment signifi cantly inhibited $H_2O_2$-induced up-regulation of MMP-1 mRNA, MMP-1 protein expression and MMP-1 activity in cultured HaCaT keratinocytes. In addition, baicalein decreased the transcriptional activity of activator protein-1 (AP-1) and the expression of c-Fos and c-Jun, both components of the heterodimeric AP-1 transcription factor. Furthermore, baicalein reduced phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun-N-terminal kinase (JNK), which are upstream of the AP-1 transcription factor. The results of this study suggest that baicalein is involved in the inhibition of oxidative stress-induced expression of MMP-1 via inactivation of the ERK/JNK/AP-1 signaling pathway.

• Biomolecules & Therapeutics
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• 제29권2호
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• pp.175-183
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• 2021

The mitogen-activated protein kinase (MAPK) pathway controls intestinal epithelial barrier permeability by regulating tight junctions (TJs) and epithelial cells damage. Heme oxygenase-1 (HO-1) and carbon monoxide (CO) protect the intestinal epithelial barrier function, but the molecular mechanism is not yet clarified. MAPK activation and barrier permeability were studied using monolayers of Caco-2 cells treated with tissue necrosis factor α (TNF-α) transfected with FUGW-HO-1 or pLKO.1-sh-HO-1 plasmid. Intestinal mucosal barrier permeability and MAPK activation were also investigated using carbon tetrachloride (CCl4) administration with CoPP (a HO-1 inducer), ZnPP (a HO-1 inhibitor), CO releasing molecule 2 (CORM-2), or inactived-CORM-2-treated wild-type mice and mice with HO-1 deficiency in intestinal epithelial cells. TNF-α increased epithelial TJ disruption and cleaved caspase-3 expression, induced ERK, p38, and JNK phosphorylation. In addition, HO-1 blocked TNF-α-induced increase in epithelial TJs disruption, cleaved caspase-3 expression, as well as ERK, p38, and JNK phosphorylation in an HO-1-dependent manner. CoPP and CORM-2 directly ameliorated intestinal mucosal injury, attenuated TJ disruption and cleaved caspase-3 expression, and inhibited epithelial ERK, p38, and JNK phosphorylation after chronic CCl4 injection. Conversely, ZnPP completely reversed these effects. Furthermore, mice with intestinal epithelial HO-1 deficient exhibited a robust increase in mucosal TJs disruption, cleaved caspase-3 expression, and MAPKs activation as compared to the control group mice. These data demonstrated that HO-1-dependent MAPK signaling inhibition preserves the intestinal mucosal barrier integrity by abrogating TJ dysregulation and epithelial cell damage. The differential targeting of gut HO-1-MAPK axis leads to improved intestinal disease therapy.

• KSBB Journal
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• 제20권1호
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• pp.21-25
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• 2005

흔하게 사용되어온 제초제인 paraquat는 파킨슨병의 원인이 될 수 있는 유력한 위험 요소이다. 헴산화효소-1(HO-1)은 산화적 스트레스와 소포체 스트레스의 marker인데, 여러 가지 자극에 의해 heme을 분해하여 biliverdin, 일산화탄소, 철 성분으로 전환시킨다 본 연구에서는 뇌의 흑색질 유래의 도파민 세포주 SN4741에서 paraquat가 시간별, 농도별로 HO-1을 활성화시키는 기작을 조사하였다. HO-1이 Paraquat에 의해 활성화되는 것은 주로 유전자 전사 수준에서 조절되었다. HO-1 유전자의 promoter와 5' enhancer인 El, E2를 결실시킨 실험에서, E2 enhancer가 도파민 세포에서 paraquat에 의한 HO-1 유전자 발현을 유도하는 핵심 부위로 판명되었다 E2 enhancer 부위를 돌연변이 시킨 실험 결과는 전사인자 활성 단백질-1 (AP-1) 결합부위를 통해 HO-1 발현이 유도됨을 밝히게 되었다. 또한, 도파민 세포에서 HO-1 유전자 발현의 조절과 신호전달 과정의 관계를 조사하기 위해 MAP kinase들의 특이적 저해제를 처리하고 paraquat로 자극을 준 결과, JNK 저해제인 SP600125가 가장 현저하게 paraquat에 의한 HO-1 발현을 억제하였다. 결론적으로, 도파민 세포에서 paraquat가 HO-1을 유도하는 데는 E2 enhancer가 중요하게 작용하고, AP-1과 JNK 경로를 통해 HO-1 발현이 조절된다는 사실을 처음으로 밝히게 되었다.

• 한국임상수의학회지
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• 제28권6호
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• pp.549-554
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• 2011

FK506은 말기 간암환자의 간이식 후 널리 사용되는 면역억제제이다. Dexamethasone은 세포독성 암 치료에서 오심 방지, 정상세포의 보호와 기타 이유 등의로 빈번하게 병용처치된다. 본 연구의 목적은 간암세포주(Hep3B)에서 FK506의 항암효과와 FK506에 의한 항암효과에 대한 dexamethasone의 억제효과를 알아보기 위함이다. 세포의 손상은 세포 생존성 평가와 LDH 및 세포내 ROS 양의 측정으로 평가 하였다. 세포내 칼슘 농도([$Ca^{2+}$]i)와 JNK, Bax 단백질의 발현 정도도 평가하였다. FK506의 처치는 Hep3B의 세포사를 유도하였으며 세포생존성의 감소와 LDH, ROS 및 [$Ca^{2+}$]i 를 증가시켰다. FK506은 Bax와 JNK 의 활성을 증가시켰으며 Bcl-2의 활성을 억제하였다. Dexamethasone 처치 그 자체는 세포생존성, LDH와 ROS에 영향을 주지 않았다. 그러나 dexamethasone과 FK506의 병용처치는 FK506에 의한 LDH 방출, ROS 생성 및 JNK의 활성을 감소시켰다. 이 결과는 간암세포주에서 FK506은 항암효과를 가지지만 dexamethasone의 병용처치는 FK506에 의한 항암효과를 길항한다.

• Clinical and Experimental Reproductive Medicine
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• 제36권3호
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• pp.187-197
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• 2009

목 적: 단백질 인산화는 세포신호전달에 매우 중요한 현상으로서, 수많은 조절인자들이 난자성숙에 관여하게 된다. 그러나 이들 중에서 어떤 단백질이 인산화되어 난자성숙을 조절하는지는 잘 알려져 있지 않다. 따라서 체세포의 신호전달과정에서 인산화를 통해 중요한 기능을 한다고 알려져 있는 일곱 가지 단백질들이 생쥐의 난자성숙과정에서 어떻게 인산화 되고 있는지 알아보고자 한 개 샘플에서 일곱 개의 변화를 한꺼번에 측정할 수 있는 bead-based multiplex phosphorylation assay를 이용하여 본 연구를 수행하였다. 연구방법: ICR 생쥐에 PMSG를 주사하고 46시간 후에 cumulus-oocyte complex (COCs) 형태로 미성숙 난자를 채취한 후 체외배양 하면서, 배양 2시간 후에 GVBD를, 배양 8시간 후에 MI을, 배양 16시간 후에 MII 단계의 난자를 얻었고 체내에서 배란한 MII 단계의 난자는 수란관에서 얻었다. 각 단계의 난자를 100개씩 모아서 mitogen-activated protein kinase (MAPK)에 속하는 세가지 단백질인 ERK1/2, JNK, p38 MAPK와 Akt, GSK-$3{\alpha}/{\beta}$, $I{\kapa}B{\alpha}$, STAT3 등 총 일곱 단백질의 인산화를 Bio-Plex System을 이용하여 같은 시료에서 동시에 측정하였으며 세 번의 반복실험을 통하여 얻어진 결과를 통계적으로 분석하였다. 결 과: 생쥐의 난자성숙과정에서 측정된 일곱 가지 단백질 중에서 인산화가 현저히 증가하는 단백질로는 ERK1/2, JNK, p38 MAPK와 STAT3로서 미성숙 난자에 비해서 3배에서 20배까지 인산화되는 결과를 보였다. 반면에 GSK-$3{\alpha}/{\beta}$, $I{\kappa}B{\alpha}$의 인산화의 변화는 미약하였으며, Akt의 경우에는 변화가 전혀 없었다. 난자성숙 과정에서 분석 대상 단백질들의 인산화는 GVBD 단계에서 활성화되기 시작하여 MI에서 현저히 높게 증가하며 MII까지 높게 유지되었다. 결 론: 본 연구는 난자성숙과정에서 일곱 가지 단백질의 인산화를 동시에 측정한 최초의 보고로서 이 방법은 난자와 같이 적은 양의 시료에서의 여러 개의 단백질 인산화를 동시에 분석하는데 유용할 것으로 생각된다. 본 연구결과, 세 가지 MAPK 단백질인 ERK1/2, JNK, p38 MAPK 외에도 STAT3가 난자성숙에 있어서 매우 중요한 조절자로 생각되었다. 또한 Akt의 473번 serine기의 인산화는 난자성숙에 관여하지 않음을 알 수 있었다.

• Biomolecules & Therapeutics
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• 제28권5호
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• pp.423-430
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• 2020

Telmisartan is an angiotensin-II receptor blocker and acts as a selective modulator of peroxisome proliferator-activated receptor gamma (PPARγ). Several studies have demonstrated that telmisartan ameliorates depression and memory dysfunction and reduces brain inflammation. We hypothesized that the beneficial effects of telmisartan on brain could be due to modulation of the blood-brain barrier (BBB) function. Here, we examined the effect of telmisartan on tumor necrosis factor alpha (TNF-α)-induced expression of intercellular adhesion molecule 1 (ICAM-1) which plays an important role in leukocyte transcytosis through the BBB. Telmisartan blocked TNF-α-induced ICAM-1 expression and leukocyte adhesion in U87MG human glioma cells but showed no effect on human brain microvascular endothelial cells. In U87MG cells, a PPAR antagonist, GW9662 did not block the effect of telmisartan on ICAM1 expression but rather potentiated. Moreover, GW9662 caused no change in TNF-α-induced ICAM-1 expression, suggesting no implication of PPARγ in the telmisartan effect. Further studies showed that telmisartan blocked TNF-α-induced activation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and nuclear factorkappa B (NF-κB). In contrast, inhibitors of JNK, ERK1/2 and NF-κB but not p38, blocked ICAM-1 expression induced by TNF-α. Thus, our findings suggest that the beneficial effect of telmisartan is likely due to the reduction of astrocytic ICAM1 expression and leukocytes adhesion to astrocytes, and that this response was mediated by the inhibition of JNK/ERK1/2/NF-κB activation and in the PPAR-independent manner. In conclusion, this study enhances our understanding of the mechanism by which telmisartan exerts the beneficial brain function.