• The Korean Journal of Physiology and Pharmacology
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• 제17권5호
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• pp.447-453
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• 2013

Osteoblastic activity of nectandrin A was examined in C2C12 cells. Nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization, manifested by the up-regulation of differentiation markers (alkaline phosphatase and osteogenic genes) and increased calcium contents. In C2C12 cells co-transfected with expression vector encoding Smad4 and Id1-Luc reporter, nectandrin A increased Id1 luciferase activity in a concentration-dependent manner, when compared to that in BMP-2 treated cells, indicating that Smad signaling pathway is associated with nectandrin A-enhanced osteoblastic differentiation in C2C12 cells. In addition, nectandrin A activated p38 mitogen-activated protein kinase (MAPK) in time- and concentration-dependent manners, and phosphorylated form of pSmad1/5/8 and alkaline phosphatase activity were both decreased when the cells were pretreated with SB203580, a p38 MAPK inhibitor, suggesting that p38 MAPK might be an upstream kinase for Smad signaling pathway. Taken together, nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization of C2C12 cells via activation of p38 MAPK-Smad signaling pathway, and it has a therapeutic potential for osteoporosis by promoting bone formation.

• 통합자연과학논문집
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• 제11권2호
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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.

• 한국임상수의학회지
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• 제25권5호
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• pp.355-358
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• 2008

본 연구는 trophic factor supplementation (TFS)이 cold ischemic storage와 rewarming 동안에 신장 세포의 생존에 미치는 효과를 알아보기 위해 실시했다. p44/42와 p38 mitogen activated protein kinases (MAPK) 활성이 TFS에 의해 영향을 받는지를 Western blot을 통해 알아보았다. Apoptotic changes를 알아보기 위해 4',6'-diamino-2-phenylindole (DAPI) 염색을 실시했다. 세포생존도를 알아보기 위해 live assay를 실시하였다. 그 결과, TFS는 cold ischemic storage와 rewarming 동안 증가된 44/42와 p38 MAPK activity를 유의성 있게 감소시켰다 (p<0.05). 또한, cold ischemic storage와 rewarming에 의한 apoptotic cell 수가 TFS에 의해 감소함을 관찰했다. 마지막으로 TFS는 유의성 있게 세포 생존도를 증가시켰다 (p<0.05). 따라서, TFS는 p44/42와 p38 MAPK 활성을 감소시키고 apoptotic change를 억제함으로써 cold ischemia와 rewarming injury로부터 신장 세포를 보호하는 것으로 생각된다.

• 대한의생명과학회지
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• 제9권4호
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• pp.241-248
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• 2003

Sodium salicylate, a plant stress hormone that plays an important role(s) in defenses against pathogenic microbial and herbivore attack, has been shown to induce a variety of cell responses such as anti-inflammation, cell cycle arrest and apoptosis in animal cells. p38MAPK plays a critical role(s) in the cell regulation by sodium salicylate. However, the signal pathway for sodium salicylate-induced p38MAPK activation is yet unclear. In this study, we show that although sodium salicylate enhances reactive oxygen species (ROS) production, N-acetyl-L-cysteine, a general ROS scavenger, did not prevent sodium salicylate-induced p38MAPK, indicating ROS-independent activation of p38MAPK by sodium salicylate. Sodium salicylate-activated p38MAPK appeared to be very rapidly down-regulated 2 min after removal of sodium salicylate. Interestingly, sodium salicylate-pretreated cells remained fully responsive to re-induction of p38MAPK activity by a second sodium salicylate stimulation or by other stresses, $H_2O$$_2$ and methyl jasmonate (MeJA), thereby indicating that sodium salicylate does not exhibit both homologous and heterologous desensitization. In contrast, pre-exposure to MeJA, $H_2O$$_2$, heat shock, or hyperosmotic stress reduced the responsiveness to subsequent homologous stimulation. Sodium salicylate was able to activate p38MAPK in cells desensitized by other heterologous p38MAPK activators. These results indicate that there is a sensing mechanism highly specific to sodium salicylate for activation of p38MAPK, distinct trom pathways used by other stressors such as MeJA, $H_2O$$_2$ heat shock, and hyperosmotic stress.

• Journal of Nutrition and Health
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• 제44권3호
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• pp.196-202
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• 2011

본 연구는 EGCG의 항 당뇨 활성기전으로 췌장종양 선세포 AR42J의 분화 및 내분비기능 개선에 미치는 영향과 그 세포 신호전달 기전을 확인하였다. 그 결과 첫째, AR42J 세포에 EGCG 처리 시 췌장종양 선세포의 세포증식이 농도 의존적으로 감소되었다. 둘째, 세포사멸 유도가 유의적으로 일어나지 않는 농도인 1uM EGCG를 AR42J 세포에 처리한 결과 ngn 3, ${\alpha}$-amylase, insulin은 EGCG처리 24시간에 mRNA, 단백질 발현증가를 나타내었고 48시간에 유의적 증가를 나타내었다. 셋째, EGCG 처리 시 ERK, JNK MAP Kinase 기전은 인산화 억제를 나타내었고 반면에 p38 기전의 인산화는 48시간에 유의적 증가를 하였다. 넷째, p38기전 저해제인 SB203580을 처리하여 EGCG가 MAP Kinase 기전중의 하나인 p38 기전 인산화 활성의 회복을 나타내어 ngn 3 발현을 위한 전사 신호전달 기전임을 다시 확인하였다. 따라서 녹차 생리활성 성분인 EGCG의 췌장종양 선 세포 AR42J 처리 결과 EGCG는 p38 MAP Kinase 기전 활성을 통해 췌장 선세포의 분화지표인 ngn 3 발현을 증가시키며 췌장내분비 기능 지표인 ${\alpha}$-amylase, insulin 발현증가를 나타내어 세포의 내분비기능 개선에도 영향을 미치는 것으로 사료된다.

• Clinical and Experimental Reproductive Medicine
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• 제48권3호
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• pp.211-220
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• 2021

Objective: The present study aimed to investigate the possibility that curcumin (CMN) protects against methotrexate (MTX)-induced testicular damage by affecting the phospho-p38 (p-p38) mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways. Methods: Eighteen male Wistar albino rats were randomly divided into three groups. The control group was given an intragastric administration of dimethyl sulfoxide (DMSO) daily for 14 days, the MTX group was given a single intraperitoneal dose of MTX (20 mg/kg) on the 11th day, and the MTX+CMN group was given intragastric CMN (100 mg/kg/day, dissolved in DMSO) for 14 days and a single intraperitoneal dose of MTX (20 mg/kg) on the 11th day. At the end of the experiment, all animals were sacrificed and the testicular tissues were removed for morphometry, histology, and immunohistochemistry. Body and testicular weights were measured. Results: Body weights, seminiferous tubule diameter, and germinal epithelium height significantly decreased in the MTX group compared to the control group. Whereas, the number of histologically damaged seminiferous tubules and interstitial space width significantly increased in the MTX group. In addition, the number of p-p38 MAPK immunopositive cells and the immunoreactivity of NF-κB also increased in the MTX group compared to the control group. CMN improved loss of body weight, morphometric values, and histological damage due to MTX. CMN also reduced the number of p-p38 MAPK immunopositive cells and the NF-κB immunoreactivity. Conclusion: CMN may reduce MTX-induced testicular damage by suppressing the p38 MAPK and NF-κB signaling pathways.

• Asian Pacific Journal of Cancer Prevention
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• 제15권11호
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• pp.4519-4525
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• 2014

Oleanolic acid (OA) is a nutritional component widely distributed in various vegetables. Although it has been well recognized for decades that OA exerts certain anti-tumor activity by inducing mitochondria-dependent apoptosis, it is still unclear that what molecular signaling is responsible for this effect. In this study, we employed cancer cell lines, A549, BXPC-3, PANC-1 and U2OS to elucidate the molecular mechanisms underlying OA anti-tumor activity. We found that activation of MAPK pathways, including p-38 MAPK, JNK and ERK, was triggered by OA in both a dose and time-dependent fashion in all the tested cancer cells. Activation was accompanied by cleavage of caspases and PARP as well as cytochrome C release. SB203580 (p38 MAPK inhibitor), but not SP600125 (JNK inhibitor) and U0126 (ERK inhibitor), rescued the pro-apoptotic effect of OA on A549 and BXPC-3 cells. OA induced p38 MAPK activation promoted mitochondrial translocation of Bax and Bim, and inhibited Bcl-2 function by enhancing their phosphorylation. OA can induce reactive oxygen species (ROS)-dependent ASK1 activation, and this event was indispensable for p38 MAPK-dependent apoptosis in cancer cells. In vivo, p38 MAPK knockdown A549 tumors proved resistant to the growth-inhibitory effect of OA. Collectively, we elucidated that activation of ROS/ASK1/p38 MAPK pathways is responsible for the apoptosis stimulated by OA in cancer cells. Our finding can contribute to a better understanding of molecular mechanisms underlying the antitumor activity of nutritional components.

• The Korean Journal of Physiology and Pharmacology
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• 제14권6호
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• pp.353-358
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• 2010

This study demonstrates the ability of magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, to inhibit LPS-induced expression of iNOS gene and activation of NF-${\kappa}B$/Rel in RAW 264.7 cells. Immunohisto-chemical staining of iNOS and Western blot analysis showed magnolol to inhibit iNOS gene expression. Reporter gene assay and electrophoretic mobility shift assay showed that magnolol inhibited NF-${\kappa}B$/Rel transcriptional activation and DNA binding, respectively. Since p38 is important in the regulation of iNOS gene expression, we investigated the possibility that magnolol to target p38 for its anti-inflammatory effects. A molecular modeling study proposed a binding position for magnolol that targets the ATP binding site of p38 kinase (3GC7). Direct interaction of magnolol and p38 was further confirmed by pull down assay using magnolol conjugated to Sepharose 4B beads. The specific p38 inhibitor SB203580 abrogated the LPS-induced NF-${\kappa}B$/Rel activation, whereas the selective MEK-1 inhibitor PD98059 did not affect the NF-${\kappa}B$/Rel. Collectively, the results of the series of experiments indicate that magnolol inhibits iNOS gene expression by blocking NF-${\kappa}B$/Rel and p38 kinase signaling.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권3호
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• pp.227-237
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• 2007

Microglial cell activation is known to contribute to neuropathic pain following spinal sensory nerve injuries. In this study, I investigated its mechanisms in the case of trigeminal sensory nerve injuries by which microglial cell and p38 mitogen-activated protein kinase (p38 MAPK) activation in the medullary dorsal horn (MDH) would contribute to the facial pain hypersensitivity following mandibular nerve transection (MNT). And also investigated the changes of trigeminal ganglion neurons and ERK, p38 MAPK manifestations. Activation of microglial cells was monitored at 1, 3, 7, 14, 28 and 60 day using immunohistochemical analyses. Microglial cell activation was primarily observed in the superficial laminae of the MDH. Microglial cell activation was initiated at postoperative 1 day, maximal at 3 day, maintained until 14 day and gradually reduced and returned to the basal level by 60 days after MNT. Pain hypersensitivity was also initiated and attenuated almost in parallel with microglial cell activation pattern. To investigate the contribution of the microglial cell activation to the pain hypersensitivity, minocycline, an inhibitor of microglial cell activation by means of p38 MAPK inhibition, was administered. Minocycline dose-dependently attenuated the development of the pain hypersensitivity in parallel with inhibition of microglial cell and p38 MAPK activation following MNT. Mandibular nerve transection induced the activation of ERK, but did not p38 MAPK in the trigeminal ganglion. These results suggest that microglial cell activation in the MDH and p38 MAPK activation in the hyperactive microglial cells play an important role in the development of facial neuropathic pain following MNT. The results also suggest that ERK activation in the trigeminal ganglion contributes microglial cell activation and facial neuropathic pain.

• Molecules and Cells
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• 제22권1호
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• pp.44-50
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• 2006

We investigated the possible role of p38 MAPK and $ET_B$ receptors in ET-1 induction of cyclooxygenase-2 (COX-2) and prostaglandin $E_2$ ($PGE_2$) in cultured feline esophageal smooth muscle cells (ESMC). Confluent layers of ESMC were stimulated with 10 nM ET-1 and expression of COX-1 and COX-2, involvement of receptors, and activation of p38 MAPK, were examined by Western blot analysis. Levels of $PGE_2$ induced by ET-1 were measured by Elisa. Using $ET_A$and $ET_B$ antagonists (BQ-123 and BQ-788, respectively), the contribution of the ET receptors to COX-1 and COX-2 expression induced by ET-1 was determined. Western blot analysis revealed that treatment of ESMC with ET-1 resulted in transient expression of COX-2 and activation of p38 MAPK. Activation of p38 MAPK was maximal after 1 h. SB202190, a p38 MAPK inhibitor, reduced expression of COX-2, but not COX-1. ET-1-induced release of $PGE_2$ was also blocked by SB202190. COX-2 expression was upregulated only via the $ET_B$ receptor, and COX-1 expression was not affected by either antagonist. Taken together, our data suggest that ET-1 causes p38 MAPK-dependent expression of COX-2 by interacting with $ET_B$ receptors on ESMC.