• The Korean Journal of Physiology and Pharmacology
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• 제21권3호
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• pp.293-300
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• 2017

Prostaglandin $D_2$ ($PGD_2$) may act against myocardial ischemia-reperfusion (I/R) injury and play an anti-inflammatory role in the heart. Although the effect of $PGD_2$ in regulation of ANP secretion of the atrium was reported, the mechanisms involved are not clearly identified. The aim of the present study was to investigate whether $PGD_2$ can regulate ANP secretion in the isolated perfused beating rat atrium, and its underlying mechanisms. $PGD_2$ (0.1 to $10{\mu}M$) significantly increased atrial ANP secretion concomitantly with positive inotropy in a dose-dependent manner. Effects of $PGD_2$ on atrial ANP secretion and mechanical dynamics were abolished by AH-6809 ($1.0{\mu}M$) and AL-8810 ($1.0{\mu}M$), $PGD_2$ and prostaglandin $F2{\alpha}$ ($PGF2{\alpha}$) receptor antagonists, respectively. Moreover, $PGD_2$ clearly upregulated atrial peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) and the $PGD_2$ metabolite 15-deoxy-${\Delta}12$, 14-$PGJ_2$ (15d-$PGJ_2$, $0.1{\mu}M$) dramatically increased atrial ANP secretion. Increased ANP secretions induced by $PGD_2$ and 15d-$PGJ_2$ were completely blocked by the $PPAR{\gamma}$ antagonist GW9662 ($0.1{\mu}M$). PD98059 ($10.0{\mu}M$) and LY294002 ($1.0{\mu}M$), antagonists of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signaling, respectively, significantly attenuated the increase of atrial ANP secretion by $PGD_2$. These results indicated that $PGD_2$ stimulated atrial ANP secretion and promoted positive inotropy by activating $PPAR{\gamma}$ in beating rat atria. MAPK/ERK and PI3K/Akt signaling pathways were each partially involved in regulating $PGD_2$-induced atrial ANP secretion.

• Molecules and Cells
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• 제39권1호
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• pp.40-45
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• 2016

Peroxiredoxins are highly conserved and abundant peroxidases. Although the thioredoxin peroxidase activity of peroxiredoxin (Prx) is important to maintain low levels of endogenous hydrogen peroxide, Prx have also been shown to promote hydrogen peroxide-mediated signalling. Mitogen activated protein kinase (MAPK) signalling pathways mediate cellular responses to a variety of stimuli, including reactive oxygen species (ROS). Here we review the evidence that Prx can act as both sensors and barriers to the activation of MAPK and discuss the underlying mechanisms involved, focusing in particular on the relationship with thioredoxin.

• Journal of Applied Biological Chemistry
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• 제64권3호
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• pp.277-284
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• 2021

The emergence and rapid spread of the potentially fatal coronavirus disease 2019, caused due to infection by severe acute respiratory syndrome coronavirus-2, has led to worldwide interest in developing functional bioactive ingredients that act as immunomodulatory agents. In this study, we aimed to characterize Carica papaya extract and explore its potential as an immunomodulator by performing in vitro cell screening. Papaya leaf water extract (PLW) was found to significantly increase the levels of nitric oxide (NO) and prostaglandin E₂ (PGE₂) by upregulating inducible nitric oxide synthase and cyclo-oxygenase-2 activity, respectively. Additionally, PLW increased the production of tumor necrosis factor-α and interleukin 1β in RAW 264.7 cells. Furthermore, PLW activated the expression of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) but not that of p38 mitogen-activated protein kinase. These results indicate that PLW increased the production of NO, PGE₂, and pro-inflammatory cytokines by activating the JNK and ERK pathways in macrophages, thus demonstrating immunomodulatory properties. Finally, high-performance liquid chromatography fingerprint analysis indicated the presence of rutin, narirutin, and ρ-coumaric acid in PLW (6.30, 119.76, and 47.25 ppm, respectively). Treating cells with these compounds at non-toxic concentrations had no effect on NO production. Taken together, these results suggest that PLW may have potential as an immunity-enhancing supplement.

• Archives of Pharmacal Research
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• 제29권11호
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• pp.1024-1031
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• 2006

The role of mitogen-activated protein kinase (MAPK) in the decreased contractile response to phorbol ester in aortic smooth muscle strips from deoxycorticosterone acetate (DOCA)-salt hypertensive rats was examined. Norepinephrine (NE) evoked greater contractility in aortic strips from DOCA rats than in those of sham-operated rats. 12-Deoxyphorbol 13-isobutyrate (DPB) induced contraction in $Ca^{2+}-free$ medium, which was diminished in strips from DOCA rats compared to sham-operated rats. Vasoconstrictions induced by these stimulants were inhibited by SB203580 and PD098059, inhibitors of p38 MAPK and extracellular signal-regulated kinase (ERK) 1/2, respectively, in both strips. The phosphorylation of p38 MAPK and ERK1/2 induced by NE was greater in strips from DOCA rats compared to those from sham-operated rats, and this phosphorylation was inhibited by the kinase inhibitors. DPB increased the phosphorylation of p38 MAPK and ERK1/2 in strips from both animals, and the increment of p38 MAPK phosphorylation by the stimulant was diminished in strips from DOCA rats compared to sham-operated rats. These findings suggest that the $Ca^{2+}-independent$ contraction evoked by DPB results from the activation of MAPKs in rat aortic smooth muscle and that the attenuated contractility by DPB in DOCA rat appears to be associated with diminished p38 MAPK activity.

• 대한통합의학회지
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• 제11권3호
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• pp.159-169
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• 2023

Purpose : Though other Citrus spp. have reported their anti-inflammatory and antioxidative activities in previous studies, the biological activity of Kiyomi (Citrus unshiu × C. sinensis) has not been reported yet. Therefore, this study attempted to analyze the anti-inflammatory mechanisms of Kiyomi leaf ethanol extract (KLEE) in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Methods : The cytotoxic effect of KLEE in RAW 264.7 cells was determined by WST-1 assay. Bacterial endotoxin, the concentration of nitric oxide (NO) was analyzed by the Griess reaction. In addition, Western blot analysis was applied to measure the protein expression level of inducible NO synthase (iNOS). The phosphorylated status of the critical inflammatory transcription factor, nuclear factor (NF)-𝜅B, and its upstream signaling molecules, phosphoinositide 3-kinase (PI3K)/Akt as well as mitogen-activated protein kinases (MAPKs), were also measured by Western blot analysis. Results : KLEE was not cytotoxic up to a concentration of 200 ㎍/㎖, and protein expression levels of iNOS and cyclooxygenase (COX)-2, enzymes that counteract NO and prostaglandin (PG) E2 production, were inhibited by KLEE treatment. The phosphorylated status of PI3K/Akt as well as MAPKs including extracellular regulated kinase (ERK), c-jun NH2kinase (JNK), and p38, were significantly attenuated by KLEE treatment in LPS stimulated RAW 264.7 cells. Moreover, one of phase II enzymes, heme oxygenase (HO)-1 which has known for its anti-inflammatory capacity, was strongly induced by KLEE treatment. Conclusion : Consequently, KLEE treatment significantly attenuated the production of NO as well as the expression levels of iNOS and COX-2 in LPS-stimulated RAW 264.7 cells. The inflammatory transcription factor, NF-𝜅B, as well as its upstream signaling molecules, PI3K/Akt and MAPKs, were also diminished by KLEE treatment with statistical significance in LPS-stimulated RAW 264.7 cells. These results suggest that KLEE might be a promising candidate for the attenuation of inflammatory disorders.

• Journal of Nutrition and Health
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• 제53권5호
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• pp.452-463
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• 2020

본 연구는 AT의 뿌리를 제외한 전체 AT의 에탄올 및 물 추출물의 면역 조절 효과를 비교하고 THP-1의 cytokine 분비를 조절하는 분자 메커니즘을 조사하였다. AT의 물 추출물 및 에탄올 추출물은 THP-1 세포에 독성이 없으며 세포 증식을 증가키는 것을 확인하였다. 에탄올 추출물은 영향이 없는데 반해, 물 추출물은 THP-1의 IL-1β의 분비를 증가시켰으며 COX-2 및 iNOS 단백질의 발현을 증가시켰다. 또한, MAPK 및 Akt의 인산화와 IkBα의 분해를 유도하는 것을 확인하였다. AT에 의한 IL-1β 분비는 ERK 및 JNK 억제제에 의해 감소되었으며, TNF-α의 분비는 ERK, p38 MAPK 및 JNK 억제제에 의해 감소되었다. 흥미롭게도, p38 MAPK 억제제는 AT에 의한 IL-1β의 생성을 추가로 증가시켰다. 이 결과는 AT 지상부의 물 추출물에 MAPK 신호 전달 경로를 통해 면역 세포를 자극하여 cytokine의 생산을 유도하는 생리활성물질이 존재한다는 것을 의미한다. 따라서, AT 지상부는 면역력 강화제의 천연 소재로써 이용될 수 있을 것으로 사료된다.

• 대한물리치료과학회지
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• 제13권2호
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• pp.129-135
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• 2006

Vascular smooth muscle contraction is mediated by activation of extracellular signal-regulated kinase (ERK) 1/2, an isoform of mitogen-activated protein kinase (MAPK). However, the role of stress-activated protein kinase/c-Jun N-terminal kinase (JNK) in vascular smooth muscle contraction has not been defined. We investigated the role of JNK in the contractile response to norepinephrine (NE) in rat aortic smooth muscle. NE evoked contraction in a dose-dependent manner, and this effect was inhibited by the JNK inhibitor SP600125. NE increased the phosphorylation of JNK, which was greater in aortic smooth muscle from hypertensive rats than from normotensive rats. NE-induced JNK phosphorylation was significantly inhibited by SP600125 and the conventional-type PKC (cPKC) inhibitor Go6976, but not by the Rho kinase inhibitor Y27632 or the phosphatidylinositol 3-kinase inhibitor LY294002. Thymeleatoxin, a selective activator of cPKC, increased JNK phosphorylation, which was inhibited by $G{\ddot{o}}6976$. SP600125 attenuated the phosphorylation of caldesmon, an actin-binding protein whose phosphorylation is increased by NE. These results show that JNK contributes to NE-mediated contraction through phosphorylation of caldesmon in rat aortic smooth muscle, and that this effect is regulated by the PKC pathway, especially cPKC.

• Journal of Photoscience
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• 제9권2호
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• pp.25-28
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• 2002

The chicken pineal gland has been used for studies on the circadian clock, because it retains an intracellular phototransduction pathway regulating the phase of the intrinsic clock oscillator. Previously, we identified chicken clock genes expressed in the gland (cPer2, cPer3, cBmal1, cBmal2, cCry1, cCry2, and cClock), and showed that a cBMALl/2-cCLOCK heteromer acts as a regulator transactivating cPer2 gene through the CACGTG E-box element found in its promoter. Notably, mRNA expression of cPer2 gene is up-regulated by light as well as is driven by the circadian clock, implying that light-dependent clock resetting may involve the up-regulation of cPer2 gene. To explore the mechanism of light-dependent gene expression unidentified in animals, we first focused on pinopsin gene whose mRNA level is also up-regulated by light. A pinopsin promoter was isolated and analyzed by transcriptional assays using cultured chicken pineal cells, resulting in identification of an 18-bp light-responsive element that includes a CACGTG E-box sequence. We also investigated a role of mitogen-activated protein kinase (MAPK) in the clock resetting, especially in the E-box-dependent transcriptional regulation, because MAPK is phospholylated (activated) in a circadian manner and is rapidly dephosphorylated by light in the gland. Both pulldown analysis and kinase assay revealed that MAPK directly associates with BMAL1 to phosphorylate it at several Ser/Thr residues. Transcriptional analyses implied that the MAPK-mediated phosphorylation may negatively regulate the BMAL-CLOCK-dependent transactivation through the E-box. These results suggest that the CACGTG E-box serves not only as a clock-controlled element but also as a light-responsive element.

• 약학회지
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• 제47권1호
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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.

• BMB Reports
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• 제42권11호
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• pp.758-763
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• 2009

Cancer-associated antigen (CAGE) induces the expression of matrix metalloproteinase-2 (MMP-2) by activating Akt, which in turn interacts with inhibitory kappa kinase $\beta$ ($I{\kappa}K{\beta}$) to activate nuclear factor ${\kappa}B$ (NF-${\kappa}B$). Akt and p38 mitogen activated protein kinase (p38 MAPK) are necessary for CAGE-mediated induction of the AP-1 subunit JunB, whereas extracellular regulated kinase (ERK) is necessary for the induction of fos-related antigen-1 (Fra-1). Induction of MMP-2 by CAGE requires activator of protein-1 (AP-1) to be bound. Specific binding of JunB to MMP-2 promoter sequences was shown by chromatin immunoprecipitation (ChIP) analysis.