• The Korean Journal of Physiology and Pharmacology
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• 제5권6호
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• pp.451-456
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• 2001

In rat hippocampus, kainic acid (KA; 10 mg/kg; i.p.) increased the phosphorylated forms of ERK1/2 (p-ERK1/2) and Jun kinase1 (p-JNK1), but not p-JNK2 and p38 (p-p38). The preadministration with cycloheximide (CHX; 5 mg/kg; i.p.) inhibited KA-induced increase of p-JNK1, but not p-ERK1/2. Surprisingly, the phosphorylated upstream MAP kinase kinases (p-MKKs) were not correlated with their downstream MAP kinases. The basal p-MKK1/2 levels were completely abolished by KA, which were reversed by CHX. In addition, p-MKK4 and p-MKK3/6 levels were enhanced by CHX alone, but were attenuated by KA. Thus, our results showed that KA increased the p-ERK and p-JNK levels in rat hippocampus, which were not parallel with their classical upstreamal kinases.

• 동의생리병리학회지
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• 제20권5호
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• pp.1211-1216
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• 2006

The effect of a chronic programme of either low- or moderate-to-high-intensity treadmill running on the activation of the Extracellular-signal regulated protein kinase (ERK1/2), Phosphorylated ERK 1/2(pERK1/2) and the Phosphorylated c-Jun N-terminal kinase(pJNK) pathways was determined in rat Back skin Hair follicle. Sprague-Dawley rats were assigned to one of three groups: (i) sedentary group(NE; n=10); (ii) low-intensity exercise group (Bm/min; LIE; n=10); and (iii) moderate-high-intensity exercise group(28m1min; HIE; n=10). The training regimens were planned so that animals covered the same distance and had similar utilization for both LIE and HIE exercise sessions. The report runs as follows; A single bout of LIE or HIE following 4 weeks of exercise led to a twofold increase in the phosphorylation of ERK2, pERK2 and a threefold increase in pJNKl, pERKl. ERKI phosphorylation in LIE Back skin sampled and pJNK2 in HIE Back skin sampled 48h after the last exercise bout was similar to sedentary values, while pJNK2 phosphorylation in LIE Back skin sampled was 70-80% lower than sedentary. 48h after the last exercise bout of LIE or HIE increased ERK2, pERKl and pJNKl expression, with the magnitude of this increase being independent of prior exercise intensity or duration. PERK1/2, pJNKl expression was increased Three- to fourfold in Back skin Hair follicle sampled 48h after the last exercise bout irrespective of the prior exercise programme, but ERKI expression in HIE Back skin sampled was approximately 90% lower than sedentary values. In conclusion, exercise-training of different jntensities/durations results in selective postexercise activation of intracellular signal pathways, which may be one mechanism regulating specific adaptations induced by diverse training programmes.

• 생명과학회지
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• 제21권2호
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• pp.242-250
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• 2011

본 연구에서는 C2C12 근육 세포에서 IGF-I이 리간드 비의존적으로 엔드로젠 수용체 coactivator 유전자 발현에 미치는 영향에 대해 알아보았다. 그 결과 IGF-I 이 리간드 비의존적으로 엔드로젠 수용체의 coactivator인 GRIP-1, SRC-1, ARA70 유전자들의 단백질과 mRNA 발현을 증가시켰으며, p38 MAPK와 ERK1/2 신호전달 경로 억제제인 SB203580과 PD98059를 IGF-I과 함께 처리한 결과 IGF-I에 의한 엔드로젠 수용체 coactivator 유전자 발현의 증가를 감소시켰음을 알 수 있었다. 엔드로젠 수용체 coactivator가 엔드로젠 물질이 없이도 IGF-I에 의해 발현이 증가하였다는 사실은 운동에 의해 근육에서 분비가 증가하는 IGF-I이 리간드 비의존적으로 근육 세포에서 엔드로젠 수용체 활성화 안정에 기여하는 엔드로젠 수용체 coactivator를 활성화 시킬 수 있다는 사실을 증명 하였다는데 의의가 있다고 사료된다. 또한, IGF-I의 하부신호전달 경로로 잘 알려진 p38 MAPK와 ERK1/2 신호전달 경로를 차단하였을 때는 발현이 억제되었는데 이를 통해 IGF-I이 근육세포 내에서 p38 MAPK, ERK1/2 경로를 통해 엔드로젠 수용체 coactivator 발현에 중요한 역할을 한다는 사실을 확인할 수 있었다. 이러한 결과는 근육에서 중요한 기능을 담당하는 IGF-I이 엔드로젠 수용체 coactivator 유전자 발현을 조절하는 기능이 있으며 이러한 IGF-I에 의한 리간드 비의존적인 엔드로젠 수용체 coactivator 유전자 발현 조절에 있어 p38 MAPK와 ERK1/2는 필수적인 신호전달 경로임을 확인하였다는 데서 그 의의가 있다고 할 수 있겠다. 향후 다양한 성장인자들에 의한 coactivator 발현에 관한 연구를 비롯하여, corepressor의 발현 억제 기능 및 신호전달 경로에 관한 연구가 추가적으로 이루어져야 할 것이다.

• Journal of Ginseng Research
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• 제46권3호
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• pp.426-434
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• 2022

Aim: This study investigates the effects of ginsenoside Rb1 (GsRb1) on methamphetamine (METH)-induced toxicity in SH-SY5Y neuroblastoma cells and METH-induced conditioned place preference (CPP) in adult Sprague-Dawley rats. It also examines whether GsRb1 can regulate these effects through the NR2B/ERK/CREB/BDNF signaling pathways. Methods: SH-SY5Y cells were pretreated with GsRb1 (20 mM and 40 mM) for 1 h, followed by METH treatment (2 mM) for 24 h. Rats were treated with METH (2 mg/kg) or saline on alternating days for 10 days to allow CPP to be examined. GsRb1 (5, 10, and 20 mg/kg) was injected intraperitoneally 1 h before METH or saline. Western blot was used to examine the protein expression of NR2B, ERK, P-ERK, CREB, P-CREB, and BDNF in the SH-SY5Y cells and the rats' hippocampus, nucleus accumbens (NAc), and prefrontal cortex (PFC). Results: METH dose-dependently reduced the viability of SH-SY5Y cells. Pretreatment of cells with 40 µM of GsRb1 increased cell viability and reduced the expression of METH-induced NR2B, p-ERK, p-CREB and BDNF. GsRb1 also attenuated the expression of METH CPP in a dose-dependent manner in rats. Further, GsRb1 dose-dependently reduced the expression of METH-induced NR2B, p-ERK, p-CREB, and BDNF in the PFC, hippocampus, and NAc of rats. Conclusion: GsRb1 regulated METH-induced neurotoxicity in vitro and METH-induced CPP through the NR2B/ERK/CREB/BDNF regulatory pathway. GsRb1 could be a therapeutic target for treating METH-induced neurotoxicity or METH addiction.

• International Journal of Oral Biology
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• 제31권1호
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• pp.21-26
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• 2006

Periodontopathogens including Porphyromonas gingivalis interact with host periodontal cells and the excessive subsequent host responses contribute a major part to the development of periodontal diseases. Cyclooxygenase(COX)-2-synthesized $PGE_2$ has detrimental activities in terms of periodontal pathogenesis. The present study investigated induction of COX-2 expression by P. gingivalis in human monocytic THP-1 cells. Live P. gingivalis increased expression of COX-2, but not that of COX-1, which was demonstrated at both mRNA and protein levels. Elevated levels of $PGE_2$ were released from P. gingivalis-infected THP-1 cells. Pharma-cological inhibition of p38 mitogen-activated protein kinase(MAPK) and extracellular signal-regulated kinase(ERK) substantially attenuated P. gingivalis-induced COX-2 mRNA expression. Indeed, activation of p38 MAPK and ERK was observed in P. gingivalis-infected THP-1 cells. Also, P. gingivalis induced activation of nuclear $factor-{\kappa}B\;(NF-{\kappa}B)$ which is an important transcription factor for COX-2. These results suggest that COX-2 expression is up regulated in P. gingivalis-infected monocytic cells, at least in part, via p38 MAPK, ERK, and $NF-{\kappa}B$.

• The Korean Journal of Physiology and Pharmacology
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• 제20권6호
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• pp.595-603
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• 2016

Ribosomal S6 kinase is a family of serine/threonine protein kinases involved in the regulation of cell viability. There are two subfamilies of ribosomal s6 kinase, (p90rsk, p70rsk). Especially, p90rsk is known to be an important downstream kinase of p44/42 MAPK. We investigated the role of p90rsk on ethanol-induced cell proliferation of HepG2 cells. HepG2 cells were treated with 10~50 mM of ethanol with or without ERK and p90rsk inhibitors. Cell viability was measured by MTT assay. The expression of pERK1, NHE1 was measured by Western blots. The phosphorylation of p90rsk was measured by ELISA kits. The expression of Bcl-2 was measured by qRT-PCR. When the cells were treated with 10~30 mM of ethanol for 24 hour, it showed significant increase in cell viability versus control group. Besides, 10~30 mM of ethanol induced increased expression of pERK1, p-p90rsk, NHE1 and Bcl-2. Moreover treatment of p90rsk inhibitor attenuated the ethanol-induced increase in cell viability and NHE1 and Bcl-2 expression. In summary, these results suggest that p90rsk, a downstream kinase of ERK, plays a stimulatory role on ethanol-induced hepatocellular carcinoma progression by activating anti-apoptotic factor Bcl-2 and NHE1 known to regulate cell survival.

• BMB Reports
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• 제49권4호
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• pp.220-225
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• 2016

Cancer cells have different characteristics due to the genetic differences where these unique features may strongly influence the effectiveness of therapeutic interventions. Here, we show that the spontaneous reactivation of extracellular signalregulated kinase (ERK), distinct from conventional ERK activation, represents a potent mechanism for cancer cell survival. We studied ERK1/2 activation in vitro in SW480 colorectal cancer cells. Although ERK signaling tends to be transiently activated, we observed the delayed reactivation of ERK1/2 in epidermal growth factor (EGF)-stimulated SW480 cells. This effect was observed even after EGF withdrawal. While phosphorylated ERK1/2 translocated into the nucleus following its primary activation, it remained in the cytoplasm during late-phase activation. The inhibition of primary ERK1/2 activation or protein trafficking, blocked reactivation and concurrently increased caspase 3 activity. Our results suggest that the biphasic activation of ERK1/2 plays a role in cancer cell survival; thus, regulation of ERK1/2 activation may improve the efficacy of cancer therapies that target ERK signaling.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.903-913
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• 2011

Vibrio parahaemolyticus, which causes gastroenteritis, wound infection, and septicemia, has two sets of type III secretion systems (TTSS), TTSS1 and TTSS2. A TTSS1-deficient vcrD1 mutant of V. parahaemolyticus showed an attenuated cytotoxicity against HEp-2 cells, and a significant reduction in mouse lethality, which were both restored by complementation with the intact vcrD1 gene. V. parahaemolyticus also triggered phosphorylation of mitogen-activated protein kinases (MAPKs) including p38 and ERK1/2 in HEp-2 cells. The ability to activate p38 and ERK1/2 was significantly affected in a TTSS1-deficient vcrD1 mutant. Experiments using MAPK inhibitors showed that p38 and ERK1/2 MAPKs are involved in V. parahaemolyticus-induced death of HEp-2 cells. In addition, caspase-3 and caspase-9 were processed into active forms in V. parahaemolyticus-exposed HEp-2 cells, but activation of caspases was not essential for V. parahaemolyticus-induced death of HEp-2 cells, as shown by both annexin V staining and lactate dehydrogenase release assays. We conclude that secreted protein(s) of TTSS1 play an important role in activation of p38 and ERK1/2 in HEp-2 cells that eventually leads to cell death via a caspase-independent mechanism.

• 생명과학회지
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• 제29권1호
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• pp.129-134
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• 2019

이전 연구에서 전통주 주박 ethyl acetate 분획물로부터 11개의 순수물질을 분리 동정하였다. 11개의 순수물질은 caffeic acid, coumaric acid, D-mannitol, ferulic acid, hesperetin, hesperidin, naringenin, naringin, sinapic acid, syringic acid, 그리고 vanilic acid로 동정되었다. 이번 연구에서는 그들의 항염증 활성을 연구하기 위하여 LPS로 활성화된 RAW 264.7 세포에서 nitric oxide (NO) 생산을 측정하였다. 11개의 순수물질 중 hesperetin과 naringenin이 가장 높은 NO 생성 억제를 보여주었다. 또한, hesperetin은 세포 생존율에 영향 없이 농도의존적으로 NO 생산을 저해하였다. 그리고, hesperetin은 농도의존적으로 염증유전자인 iNOS의 발현을 농도의존적으로 억제한 반면, COX-2 단백질의 발현에는 영향을 주지 않았다. 게다가, hesperetin은 p38 MAPK와 ERK1/2의 인산화를 억제한 반면 JNK의 인산화에는 영향을 주지 못했다. 이러한 결과는 hesperetin은 항염증 활성을 가지며, 이러한 항염증 활성은 p38 MAPK와 ERK1/2 경로를 억제함으로써 일어난다는 것을 나타낸다.

• 동의생리병리학회지
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• 제21권1호
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• pp.76-81
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• 2007

The effect of either low or high intensity four weeks exercise treadmill running on the activation of the extracellular-signal regulated protein kinase (ERK1/2) and the c-Jun N-terminal kinase(JNK) pathways was determined in rat tibialis muscle. Sprague-Dawley rats were assigned to one of three groups: (i) sedentary group(NE; n=10); (ii) low intensity exercise group (8m/min; LIE; n=10); and (iii) high intensity exercise group(28m/min; HIE; n=10). The training regimens were planned so that animals covered the same distance and had similar glycogenutilization for both LIE and HIE exercise sessions. After four weeks exercise, 48 h after the last exercise bout obtained samples. pERK1 increased 1.5 times comparing with the sedentary group in the low intensity group while it increased 11.7 times in high intensity group, in the tibialis of rats. In the low intensity group, pERK2 increased 1.4 times comparing with the sedentary group while it increased 3.3 times in high intensity group. While pJNK1 decreased 0.9 times, comparing with the sedentary group, pJNK2 was increased to 0.5 times in the low intensity group. But in high intensity group, pJNK2 decreased 0.7 times while pJNK1 didn't show any change. In conclusion, Four weeks exercise of different intensities results in tibialis muscle activation of intracellular signal pathways, which may be one mechanism regulating specific adaptations induced by different exercise intensities.