• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.311-323
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• 2007

Receptor activation of nuclear factor ${\kappa}$ B ligand (RANKL)은 파골세포의 분화와 기능에 중요한 역할을 하는 단백질로 이들 물질의 조절에는 p38 MAP kinase가 관여한다. 그러나 치주인대 섬유모세포에서 RANKL 발현 시 p38 MAP kinase의 역할은 잘 알려져 있지 않다. 이에 이번 연구는 마우스 치주인대 섬유모세포의 $IL-1{\beta}-induced$ RANKL 발현과정에서 p38의 역할을 규명하고자 하여 다음과 같은 결과를 얻었다. 마우스 치주인대 섬유모세포에 $IL-1{\beta}$ (1ng/ml)의 자극은 수용성 RANKL의 합성을 증가시켰다. 수용성 RANKL의 합성은 p38 MAP kinase 억제제인 SB203580에 의해 농도 의존적으로 억제되었으나 다른 MAP kinase 억제제인 SP600125, JNK 억제제와 PD98059, ERK 억제제에 의해서는 수용성 RANKL의 합성이 조절되지 않았다. NF-kB 억제제에 의해서도 수용성 RANKL의 합성이 억제되지 않았다. RANKL 유전자의 발현은 $IL-1{\beta}$로 자극 시에는 대조군에 비해 약 5배의 발현 증가를 보였으나 SB203580으로 전처치 시 $IL-1{\beta}$ (1ng/ml)로 자극시보다 약 1.5배의 감소를 보였다. 그러나 SP600125, PD98059, 및 NF-kB 억제제로 전처치한 경우에는 $IL-1{\beta}$로 자극한 경우와 비슷한 수준을 보였다. $IL-1{\beta}$로 자극 시 RANKL 유전자의 반감기가 90분 이었으나 SB203580로 전처치 후 $IL-1{\beta}$로 자극 시 RANKL 유전자의 반감기는 60분으로 감소하였다. Cycloheximide 전처리 시 SB203580에 의한 RANKL 유전자 발현 억제가 관찰되지 않았다. 단백질 분석결과 p38 MAP kinase의 인산화 활성은 30분까지 증가하였으나 그 이후 감소하여 2시간째에는 그 발현이 미약하였다. SB203580로 전처치 후 $IL-1{\beta}$로 자극 시 p38 MAP kinase의 인산화 활성이 감소하였다. 이상의 결과는 p38 MAP kinase가 RANKL 유전자 조절에 중요한 역할을 담당하고 있음을 시사한다.

• Journal of Integrative Natural Science
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• v.11 no.2
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• pp.107-112
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• 2018

p38 MAP kinase belongs to the Mitogen-activated protein (MAP) kinase family; a serine/threonine kinase. It plays an important role in intracellular signal transduction pathways. It is associated with the development and progression of various cancer types making it a crucial drug target. Present study involves the HQSAR analysis of recently reported imidazo[1,2-b]pyridazine derivatives as p38 MAP kinase antagonists. The model was generated with Atom (A), bond (B), chirality (Ch), and hydrogen (H) parameters and with different set of atom counts to improve the model. An acceptable HQSAR model ($q^2=0.522$, SDEP=0.479, NOC=5, $r^2=0.703$, SEE=0.378, BHL=97) was developed which exhibits good predictive ability. A contribution map for the most active compound (compound 17) illustrated that hydrogen and nitrogen atoms in the ring A and ring B, as well as nitrogen atom in ring C and the hydrogen atom in the ring D provided positive activity in inhibitory effect while, the least active compound (compound 05) possessed negative contribution to inhibitory effect. Hence, analysis of produced HQSAR model can provide insights in the designing potent and selective p38 MAP kinase antagonists.

• Animal cells and systems
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• v.9 no.3
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• pp.173-179
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• 2005

Cyclic-AMP-dependent protein kinase (PKA) seems to function as a negative regulator of the c-Jun $NH_2-terminal$ kinase (JNK) signaling pathway. We demonstrate here that the activity of the PKA catalytic subunit (PKAc) is reduced in apoptotic PC12 pheochromocytoma cells. Apoptotic progress was inhibited by dibutyryl cyclic AMP (dbcAMP), an analog of cAMP. The rescue by dbcAMP was attributable to inhibition of the JNK but not of the p38 signaling pathway, due to the induction of PKA activity. JNK was present in immunocomplexes of PKAc, and PKAc phosphorylated JNK in vitro. Presence of p38 kinase, however, was not prominent in immunocomplexes of PKAc. Our data suggest that JNK is a target point of negative regulation by PKAc in the JNK signaling pathway.

• IMMUNE NETWORK
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• v.6 no.4
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• pp.204-210
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• 2006

Background: Nitric oxide (NO) in articular chondrocytes regulates dedifferentiation and inflammatory responses by modulating MAP kinases. In this study, we investigated whether the Src kinase in chondrocytes regulates NO-induced dedifferentiation and cyclooxygenase-2 (COX-2) expression. Methods: Primary chondrocytes were treated with various concentrations of SNP for 24 h. The COX-2 and type II collagen expression levels were determined by immunoblot analysis, and prostaglandin $E_2\;(PGE_2)$ was determined by using a $PGE_2$ assay kit. Expression and distribution of p-Caveolin and COX-2 in rabbit articular chondrocytes and cartilage explants were determined by immunohistochemical staining and immunocytochemical staining, respectively. Results: SNP treatment stimulated Src kinase activation in a dose-dependent manner in articular chondrocytes. The Src kinase inhibitors PP2 [4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine], a significantly blocked SNP-induced p38 kinase and caveolin-1 activation in a dose-dependent manner. Therefore, to determine whether Src kinase activation is associated with dedifferentiation and/or COX-2 expression and $PGE_2$ production. As expected, PP2 potentiated SNP-stimulated dedifferentiation, but completely blocked both COX-2 expression and $PGE_2$ production. And also, levels of p-Caveolin and COX-2 protein expression were increased in SNP-treated primary chondrocytes and osteoarthritic and rheumatoid arthritic cartilage, suggesting that p-Caveolin may playa role in the inflammatory responses of arthritic cartilage. Conclusion: Our previously studies indicated that NO caused dedifferentiation and COX-2 expression is regulated by p38 kinase through caveolin-1 (1). Therefore, our results collectively suggest that Src kinase regulates NO-induced dedifferentiation and COX-2 expression in chondrocytes via p38 kinase in association with caveolin-1.

• Journal of Nutrition and Health
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• v.44 no.3
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• pp.196-202
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• 2011

Epigallocatechin gallate (EGCG), or epigallocatechin 3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin. EGCG may be therapeutic for many disorders including diabetics and some types of cancer. However it is unknown whether EGCG can induce transdifferentiation of pancreatic cells in pancreatitis. The aim of this study was to investigate the effects of EGCG on the expression of pancreatic regenerating related markers in pancreatic AR42J cells, a model of pancreatic progenitor cells. AR42J cells, differentiated with betacellulin and activin A, were cultured with/without EGCG in a time-dependent manner. Cell growth rate, levels of mRNA, and protein expression were examined with the MTT assay, quantitative PCR, and Western blots, respectively. The results showed that AR42J cell growth rates were inhibited by EGCG in a dose-dependent manner. mRNA and protein expression of amylase, insulin and neurogenin 3 (ngn 3) increased in AR42J cells treated with EGCG. Additionally, we demonstrated that the signal transduction pathway of mitogen-activated protein (MAP) kinase is active in EGCG-treated AR42J cells. ERK and JNK phosphorylation decreased in cells treated with EGCG but not p38 phosphorylation. Activation of the p38 MAP kinase pathway was confirmed by specific MAP kinase pathways inhibitors: U0126 for ERK, SP600126 for JNK, and SB203580 for p38. Activated p38 phosphorylation was inhibited by the specific p38 inhibitor SB203580 but p38 phosphorylation was inhibited with increased EGCG treatment. The ERK and JNK MAP kinase pathways were not affected by EGCG treatment. Although further studies are needed, these results suggest that EGCG affects the induction of pancreatic cell regeneration by increasing the ngn 3 protein and mRNA expression and activating the p38 MAP kinase pathway.

• Archives of Pharmacal Research
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• v.26 no.9
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• pp.739-746
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• 2003

Ultraviolet B (UVB) is known to induce apoptosis in human melanocytes. Here we show the cytoprotective effect of sphingosine-1-phosphate (S1P) against UVB-induced apoptosis. We also show that UVB-induced apoptosis of melanocytes is mediated by caspase-3 activation and poly(ADP-ribose) polymerase (PARP) cleavage, and that S1P prevents apoptosis by inhibiting this apoptotic pathway. We further investigated three major mitogen-activated protein (MAP) kinases after UVB irradiation. UVB gradually activated c-Jun N-terminal kinase (JNK) and p38 MAP kinase, while extracellular signal-regulated protein kinase (ERK) was inactivated transiently. Blocking of the p38 MAP kinase pathway using SB203580 promoted cell survival and inhibited the activation of caspase-3 and PARP cleavage. These results suggest that p38 MAP kinase activation may play an important role in the UVB-induced apoptosis of human melanocytes. To explain this cytoprotective effect, we next examined whether S1P could inhibit UVB-induced JNK and p38 MAP kinase activation. However, S1P was not found to have any influence on UVB-induced JNK or p38 MAP kinase activation. In contrast, S1P clearly stimulated the phosphorylation of ERK, and the specific inhibition of the ERK pathway using PD98059 abolished the cytoprotective effect of S1P. Based on these results, we conclude that the activation of p38 MAP kinase plays an important role in UVB-induced apoptosis, and that S1P may show its cytoprotective effect through ERK activation in human melanocytes.

• Childhood Kidney Diseases
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• v.21 no.1
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• pp.1-7
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• 2017

Mitogen-activated protein kinases (MAPKs) play important roles in various cellular functions including proliferation, differentiation, and apoptosis. We showed that MAPKs are developmentally regulated in the rat kidney. p38 MAPK (p38) and extracellular signal-regulated kinase (ERK) were strongly expressed in the fetal kidney, whereas c-Jun N-terminal kinase (JNK) was detected predominantly in the adult kidney. The inhibition of p38 or ERK in organ culture resulted in reduced nephron formation with or without reduced kidney size. On the other hand, persistent fetal expression pattern of MAPKs, i.e., upregulation of p38 and ERK and downregulation of JNK, was observed in the cyst epithelium of human renal dysplasia, ovine fetal obstructive uropathy, and pcy mice, a model of polycystic kidney disease. Furthermore, activated p38 and ERK induced by cyclic stretch mediated proliferation and $TGF-{\beta}1$ expression in ureteric bud cells, probably leading to cyst formation and dysplastic changes. Inhibition of ERK slowed the disease progression in pcy mice. Finally, ERK and p38 were inactivated in the early embryonic kidney subjected to maternal nutrient restriction, characterized by reduced ureteric branching and nephron number. Thus, MAPKs mediate the development of normal and diseased kidney. Their modulation may result in novel therapeutic strategies against developmental abnormalities of the kidney.

• IMMUNE NETWORK
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• v.6 no.3
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• pp.117-122
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• 2006

Background: Caveolin, a family of integral membrane proteins are a principal component of caveolae membranes. In this study, we investigated the effect of p38 kinase on differentiation and on inflammatory responses in sodium nitroprusside (SNP)-treated chondrocytes. Methods: Rabbit articular chondrocytes were prepared from cartilage slices of 2-week-old New Zealand white rabbits by enzymatic digestion. SNP was used as a nitric oxide (NO) donor. In this experiments measuring SNP dose response, primary chondrocytes were treated with various concentrations of SNP for 24h. The time course of the SNP response was determined by incubating cells with 1mM SNP for the indicated time period $(0{\sim}24h)$. The cyclooxygenase-2 (COX-2) and type II collagen expression levels were determined by immunoblot analysis, and prostaglandin $E_2\;(PGE_2)$ assay was used to measure the COX-2 activity. The tyrosine phosphorylation of caveolin-1 was determined by immunoblot analysis and immunostaining. Results: SNP treatment stimulated tyrosine phosphorylation of caveolin-1 and activation of p38 kinase. SNP additionally caused dedifferentiation and inflammatory response. We showed previously that SNP treatment stimulated activation of p38 kinase and ERK-1/-2. Inhibition of p38 kinase with SB203580 reduced caveolin-1 tyrosine phosphorylation and COX-2 expression but enhanced dedifferentiation, whereas inhibition of ERK with PD98059 did not affect caveolin-1 tyrosine phosphorylation levels, suggesting that ERK at least is not related to dedifferentiation and COX-2 expression through caveolin-1 tyrosine phosphorylation. Conclusion: Our results indicate that SNP in articular chondrocytes stimulates dedifferentiation and inflammatory response via p38 kinase signaling in association with caveolin-1 phosphorylation.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.42-42
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• 2003

The contamination of the environment with pollutants is one of the main problems of modern life, and the levels pollution in industrialized regions are giving raise to increased public concern. The mitogen-activated protein kinase (MAP kinase) are playa pivotal role in the regulation of important cellular functions by activation of specific signal transduction pathways from cell the surface to the nuclei. Three major subgroups of MAP kinases have been identified, and these comprise the extracellular signal-regulated kinase (ERK), the c-Jun amino-terminal kinase (JNK), and the p38 MAP kinases [1-3]. Herein, we investigated the effect of regulation of phospho-JNK (p-JNK), phospho-p38 (p-p38) and phospho-ERK (p-ERK) by TCDD. (omitted)

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.85-96
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• 2006

Matrix metalloproteinases (MMPs)는 치주조직내에 존재하는 세포외기질의 유지와 분해에 중요한 역할을 담당하고 있으며 이중 MMP-13은 치주질환의 진행과 깊은 관계가 있다고 알려져 있다. 이번 연구는 치주질환의 진행에 있어서 MMP-13의 활성에 대한 mitogen activated protein(MAP) Kinase의 역할을 구명하기 위해 시행되었다. 백서 치주인대세포에서의 MMP-13 mRNA의 발현은 RT-PCR에 의하여, 그리고 MAP Kinase의 발현은 Western blot에 의하여 측정하였다. $Interleukin-1{\beta}$(IL $-1{\beta}$), Tumor necrosis $factora(TNF-{\alpha})$와 parathyroid hormon(PTH)는 MMP- 13 mRNA 발현을 각각 320%, 180%, 380% 증가시켰으나 bone morphogenetic protein-7(BMP-7)은 MMP-13 mRNA의 발현을 증가시키지 않았다. p38 MAP Kinase 억제제인 SB203580은 IL $-1{\beta}$ 유도 MMP-13의 발현을 약 40% 정도 억제시켰으나, PTH-유도 MMP-13 mRNA의 발현은 억제하지 못했다. IL $-1{\beta}$는 MMP- 13 mRNA의 반감기를 약 2시간 정도로 증가시켰으나, p38 MAP Kinase 억제제로 전처치한 경우에는 반감기가 60분으로 줄어들었다. $IL-1{\beta}$는 p38 MAP kinase와 JNK의 인산화 활성을 증가시켰으나 PTH, $TNF-{\alpha}$와 BMP-7은 p38, JNK, ERK의 활성을 증가시키지 못했다. 이상의 연구결과는 p38 MAP Kinase가 백서 치주인대세포에서의 MMP-13 mRNA 발현을 조절하는데 중요한 역할을 담당함을 시사하였다.