• The Journal of Korean Physical Therapy
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• 제20권3호
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• pp.61-68
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• 2008

Purpose: Protein kinase C (PKC) is a member of a family of serine/threonine kinases that are activated by diacylglycerol (DG) and PKC stimulants. PKC play a key role in signal transduction, including muscle contraction, cell migration, apoptosis, cell proliferation and differentiation. However, the mechanism relating mitogen-activated protein kinases (MAPKs) and PKC, especially in the volume-dependent hypertensive state, remains unclear. Methods: In the present study, I investigated the relationship between PKC and MAPKs for isometric contraction, PKC translocation, and enzymatic activity from normotensive sham-operated rats (NSR) and aldosterone-analogue deoxycorticosterone acetate (DOCA) hypertensive rats (ADHR). Results: Systolic blood pressure was significantly increased in ADHR than in NSR. Physiological salt solution (PSS)-induced resting tension and the intracellular $Ca^{2+}$ concentration ([$Ca^{2+}{_i}$]) were different in the ADHR and NSR. The expression of PKC$\alpha$, PKC$\beta$II, PKC$\delta$, PKC$\varepsilon$ and PKC$\xi$ were different between the cytoplasmic and membranous fractions. However, expression of the PKC isoforms did not differ for the ADHR and NSR. The use of 12-deoxyphorbol 13-isobutyrate (DPB, a PKC stimulant) induced isometric contraction in $Ca^{2+}$-free medium, which was diminished in muscle strips from ADHR as compared to NSR. Increased vasoconstriction and phosphorylation induced by the use of 1 ${\mu}$M DPB were inhibited by treatment with 10 ${\mu}$M PD098059 and 10 ${\mu}$M SB203580, inhibitors of extracellular-regulated protein kinase 1/2 (ERK1/2) and p38 MAPK from ADHR, respectively. Conclusion: These results suggest that the development of aldosterone analogue-induced hypertension is associated with an altered blood pressure, resting tension, [$Ca^{2+}{_i}$], and that the $Ca^{2+}$-independent contraction evoked by PKC stimulants is due to the activation of ERK1/2 and p38 MAPK in volume-dependent hypertension. Therefore, it is suggested that PKC activity affects volume-dependent hypertension and the need to develop cardiovascular disease-specialized physical therapy.

• BMB Reports
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• 제49권7호
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• pp.370-375
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• 2016

Ras oncoproteins are small molecular weight GTPases known for their involvement in oncogenesis, which operate in a complex signaling network with multiple effectors. Approximately 25% of human tumors possess mutations in a member of this family. The Raf1/MEK/Erk1/2 pathway is one of the most intensively studied signaling mechanisms. Different levels of regulation account for the inactivation of MAP kinases by MAPK phosphatases in a cell type- and stimuli-dependent manner. In the present study, using three inducible Ras-expressing NIH/3T3 cell lines, we demonstrated that MKP3 upregulation requires the activation of the Erk1/2 pathway, which correlates with the shutdown of this pathway. We also demonstrated, by applying pharmacological inhibitors and effector mutants of Ras, that induction of MKP3 at the protein level is positively regulated by the oncogenic Ras/Raf/MEK/Erk1/2 signaling pathway.

• Toxicological Research
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• 제20권3호
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• pp.233-239
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• 2004

The present study was designed to determine the impact of mercury on endotoxin-induced inflammatory cytokine expression and corresponding signal transduction in mouse kidney. Male BALB/c mice were exposed continuously to 0, 0.3, 1.5, 7.5, or 37.5 ppm of mercury in drink-ing water for 14 days and at the end of the treatment period, lipopolysaccharide (LPS, 0.5 mg/kg) was injected intraperitoneally 2 h prior to euthanasia. The doses of mercury and LPS did not cause hepatotoxicity or renal toxicity as indicated by unaltered plasma alanine aminotransferase and aspartate aminotransferase levels, and terminal UTP nucleotide end-labeling assay from kidney, respectively. Mercury decreased kidney glutathione (GSH) and with LPS, it additively decreased GSH. Mercury activated p38 mitogen-activated protein kinase (MAPK) and additively increased LPS-induced p38 MAPK phosphorylation. In contrast, mercury inhibited LPS-induced activation of extra-cellular signal-regulated kinase (ERK) but had no effect alone. Mercury increased the gene expression of tumor necrosis factor $\alpha$ (TN F$\alpha$) and potentiated LPS-induced TNF$\alpha$ expression. Mercury did not affect LPS-induced interleukin-1$\beta$ (IL-1$\beta$) expression but decreased LPS-induced IL-6 expression. These results suggest that low levels of mercury might augment LPS-induced TNF$\alpha$ expression by altering GSH and p38 MAPK. Mercury modulates LPS-induced p38 and ERK activation, and downstream TNF$\alpha$ and IL-6 expression in kidney, respectively.

• Journal of Ginseng Research
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• 제43권4호
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• pp.527-538
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• 2019

Background: Ginsenoside Rg1 was shown to exert ligand-independent activation of estrogen receptor (ER) via mitogen-activated protein kinase-mediated pathway. Our study aimed to delineate the mechanisms by which Rg1 activates the rapid ER signaling pathways. Methods: ER-positive human breast cancer MCF-7 cells and ER-negative human embryonic kidney HEK293 cells were treated with Rg1 ($10^{-12}M$, $10^{-8}M$), $17{\beta}$-estradiol ($10^{-8}M$), or vehicle. Immunoprecipitation was conducted to investigate the interactions between signaling protein and ER in MCF-7 cells. To determine the roles of these signaling proteins in the actions of Rg1, small interfering RNA or their inhibitors were applied. Results: Rg1 rapidly induced $ER{\alpha}$ translocation to plasma membrane via caveolin-1 and the formation of signaling complex involving linker protein (Shc), insulin-like growth factor-I receptor, modulator of nongenomic activity of ER (MNAR), $ER{\alpha}$, and cellular nonreceptor tyrosine kinase (c-Src) in MCF-7 cells. The induction of extracellular signal-regulated protein kinase and mitogen-activated protein kinase kinase (MEK) phosphorylation in MCF-7 cells by Rg1 was suppressed by cotreatment with small interfering RNA against these signaling proteins. The stimulatory effects of Rg1 on MEK phosphorylation in these cells were suppressed by both PP2 (Src kinase inhibitor) and AG1478 [epidermal growth factor receptor (EGFR) inhibitor]. In addition, Rg1-induced estrogenic activities, EGFR and MEK phosphorylation in MCF-7 cells were abolished by cotreatment with G15 (G protein-coupled estrogen receptor-1 antagonist). The increase in intracellular cyclic AMP accumulation, but not Ca mobilization, in MCF-7 cells by Rg1 could be abolished by G15. Conclusion: Ginsenoside Rg1 exerted estrogenic actions by rapidly inducing the formation of ER containing signalosome in MCF-7 cells. Additionally, Rg1 could activate EGFR and c-Src ER-independently and exert estrogenic effects via rapid activation of membrane-associated ER and G protein-coupled estrogen receptor.

• 생명과학회지
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• 제33권6호
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• pp.463-470
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• 2023

Desmarestia tabacoides Okamura는 전 세계적으로 널리 분포하는 갈조류 중 하나이다. 몇몇 산말류의 항종양, 멜라닌 생성 억제 및 광보호 활성에 대한 연구는 있었으나 D. tabacoides Okamura의 항염증 기전에 대해서는 보고되지 않아 본 연구에서는 LPS (lipopolysaccharide)로 자극된 RAW 264.7 세포에서 D. tabacoides Okamura 에탄올 추출물(DTEE)의 항염증 기전을 inducible nitric oxide synthase (iNOS)와 cyclooxygenase (COX)-2의 발현 및 이들의 상위신호전달물질인 nuclear factor (NF)-κB, mitogen-activated protein kinase (MAPK) 그리고 phosphoinositide-3-kinase (PI3K)/Akt의 인산화 조절 정도를 통해 분석하였다. DTEE의 처리는 세포 독성 없이 LPS로 유도된 NO와 prostaglandin (PG) E₂의 생성과 이들의 생성 효소인 iNOS 및 COX-2의 발현을 유의하게 억제하였다. 그리고 LPS에 의해 활성화된 NF-κB 및 상위 신호 전달 물질인 extracellular signal-regulated kinase (ERK), c-Jun NH₂-terminal kinase (JNK) 및 p38은 DTEE 처리에 의해 유의적으로 억제되었다. DTEE의 처리는 RAW 264.7 세포에서 LPS에 의해 활성화되는 adaptor molecule인 Toll-like receptor (TLR) 4 및 myeloid differentiation primary response (MyD) 88 또한 유의적으로 억제하였다. 이 결과를 통해 DTEE는 LPS에 의해 유도된 TLR4와 NF-κB 및 MAPK의 활성을 억제함으로써 염증 매개인자의 발현을 조절하였고, 이는 DTEE가 염증을 완화할 수 있는 기능성 식품의 소재로써 유용하게 사용될 수 있음을 시사한다.

• BMB Reports
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• 제49권8호
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• pp.437-442
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• 2016

We aimed to study the role of protein L-isoaspartyl methyltransferase (PIMT) in neuronal differentiation using basic fibroblast growth factor (bFGF)-induced neuronal differentiation, characterized by cell-body shrinkage, long neurite outgrowth, and expression of neuronal differentiation markers light and medium neurofilaments (NF). The bFGF-mediated neuronal differentiation of PC12 cells was induced through activation of mitogen-activated protein kinase (MAPK) signaling molecules [MAPK kinase 1/2 (MEK1/2), extracellular signal-regulated kinase 1/2 (ERK1/2), and p90RSK], and phosphatidylinositide 3-kinase (PI3K)/Akt signaling molecules PI3Kp110β, PI3Kp110γ, Akt, and mTOR. Inhibitors (adenosine dialdehyde and S-adenosylhomocysteine) of protein methylation suppressed bFGF-mediated neuronal differentiation of PC12 cells. PIMT-eficiency caused by PIMT-specific siRNA inhibited neuronal differentiation of PC12 cells by suppressing phosphorylation of MEK1/2 and ERK1/2 in the MAPK signaling pathway and Akt and mTOR in the PI3K/Akt signaling pathway. Therefore, these results suggested that PIMT was critical for bFGF-mediated neuronal differentiation of PC12 cells and regulated the MAPK and Akt signaling pathways.

• The Korean Journal of Physiology and Pharmacology
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• 제26권2호
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• pp.87-94
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• 2022

Myocardial infarction promotes cardiac remodeling and myocardial fibrosis, thus leading to cardiac dysfunction or heart failure. Peiminine has been regarded as a traditional anti-fibrotic Chinese medicine in pulmonary fibrosis. However, the role of peiminine in myocardial infarction-induced myocardial injury and fibrosis remained elusive. Firstly, rat model of myocardial infarction was established using ligation of the left coronary artery, which were then intraperitoneally injected with 2 or 5 mg/kg peiminine once a day for 4 weeks. Echocardiography and haemodynamic evaluation results showed that peiminine treatment reduced left ventricular end-diastolic pressure, and enhanced maximum rate of increase/decrease of left ventricle pressure (± dP/dt max) and left ventricular systolic pressure, which ameliorate the cardiac function. Secondly, myocardial infarction-induced myocardial injury and infarct size were also attenuated by peiminine. Moreover, peiminine inhibited myocardial infarction-induced increase of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α production, as well as the myocardial cell apoptosis, in the rats. Thirdly, peiminine also decreased the myocardial fibrosis related protein expression including collagen I and collagen III. Lastly, peiminine reduced the expression of p38 and phosphorylation of extracellular signal-regulated kinase 1/2 in rat model of myocardial infarction. In conclusion, peiminine has a cardioprotective effect against myocardial infarction-induced myocardial injury and fibrosis, which can be attributed to the inactivation of mitogen-activated protein kinase pathway.

• Biomolecules & Therapeutics
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• 제21권6호
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• pp.435-441
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• 2013

Emodin, a naturally occurring anthraquinone derivative isolated from Polygoni cuspidati radix, has several beneficial pharmacologic effects, which include anti-cancer, anti-diabetic, and anti-inflammatory activities. In this study, the authors examined the effect of emodin on the production of proinflammatory cytokines, such as, tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-6, in mouse bone marrow-derived mast cells (BMMCs) stimulated with phorbol 12-myristate 13-acetate (PMA) plus the calcium ionophore A23187. To investigate the mechanism responsible for the regulation of pro-inflammatory cytokine production by emodin, the authors assessed its effects on the activations of transcriptional factor nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and mitogen-activated protein kinases (MAPKs). Emodin attenuated the nuclear translocation of (NF)-${\kappa}B$ p65 and its DNA-binding activity by reducing the phosphorylation and degradation of $I{\kappa}B{\alpha}$ and the phosphorylation of $I{\kappa}B$ kinase B (IKK). Furthermore, emodin dose-dependently attenuated the phosphorylations of MAPKs, such as, extracellular signal-regulated kinase 1/2 (ERK1/2), p38 MAP kinase, and the stress-activated protein kinases (SAPK)/c-Jun-N-terminal kinase (JNK). Taken together, the findings of this study suggest that the anti-inflammatory effects of emodin on PMA plus A23187-stimulated BMMCs are mediated via the inhibition of NF-${\kappa}B$ activation and of the MAPK pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제6권6호
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• pp.319-325
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• 2002

The induction of interleukin-6 (IL-6) using combined proinflammatory agents $(LPS/IFN-{\gamma}\;or\;TNF-{\alpha}/IFN-{\gamma})$ was studied in relation to p38 mitogen-activated protein kinase (MAPK) and $NF-{\kappa}B$ transcriptional factor in primary neonatal cardiomyocytes. When added to cultures of cardiomyocytes, the combined agents $(LPS/IFN-[\gamma}\;or\;TNF-{\alpha}/IFN-{\gamma})$ had stimulatory effect on the production of IL-6 and the elevation was significantly reduced by SB203580, a specific p38 MAPK inhibitor. SB203580 inhibited protein production and gene expression of IL-6 in a concentration-dependent manner. In this study, $IFN-{\gamma}$ enhancement of $TNF-{\alpha}-induced\;NF-{\kappa}B$ binding affinity as well as p38 MAP kinase activation was observed. However, a specific inhibitor of p38 MAPK, SB203580, had no effect on $TNF-{\alpha}/IFN-{\gamma}\;or\;LPS/IFN-{\gamma}-induced\;NF-{\kappa}B$ activation. This study strongly suggests that these pathways about $TNF-{\alpha}/IFN-{\gamma}$ or $LPS/IFN-{\gamma}-activated$ IL-6 release can be primarily dissociated in primary neonatal cardiomyocytes.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2006년도 Grop Science and Biotechnology in the 21st Century
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• pp.22-22
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• 2006