• The Korean Journal of Physiology and Pharmacology
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• v.13 no.3
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• pp.161-168
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• 2009

In the peripheral nerves, injury-induced cytokines and growth factors perform critical functions in the activation of both the MEK/ERK and JAK/STAT3 pathways. In this study, we determined that nerve injury-induced ERK activation was temporally correlated with STAT3 phosphorylation at the serine 727 residue. In cultured Schwann cells, we noted that ERK activation is required for the serine phosphorylation of STAT3 by neuropoietic cytokine interleukin-6 (IL-6). Serine phosphorylated STAT3 by IL-6 was transported into Schwann cell nuclei, thereby indicating that ERK may regulate the transcriptional activity of STAT3 via the induction of serine phosphorylation of STAT3. Neuregulin-1 (NRG) also induced the serine phosphorylation of STAT3 in an ERK-dependent fashion. In contrast with the IL-6 response, serine phosphorylated STAT3 induced by NRG was not detected in the nucleus, thus indicating the non-nuclear function of serine phosphorylated STAT3 in response to NRG. Finally, we determined that the inhibition of ERK prevented injury-induced serine phosphorylation of STAT3 in an ex-vivo explants culture of the sciatic nerves. Collectively, the results of this study show that ERK may be an upstream kinase for the serine phosphorylation of STAT3 induced by multiple stimuli in Schwann cells after peripheral nerve injury.

• The Korean Journal of Pain
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• v.33 no.4
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• pp.335-343
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• 2020

Background: Zhongyi paste is a traditional Chinese medicine herbal paste that is externally applied to reduce inflammation and relieve pain. Methods: An acute foot swelling inflammation model in C57BL/6J mice was established by carrageenan-induced pathogenesis. Zhongyi paste raised the pain threshold and also reduced the degree of swelling in mice with carrageenan-induced foot swelling. Results: Analysis indicated that serum tumor necrosis factor-alpha, interleukin-1 beta, and prostaglandin E₂ (PGE₂) cytokine levels and PGE₂ levels in the paw tissue of the mice were decreased by Zhongyi paste treatment. The quantitative polymerase chain reaction and western blot results showed that Zhongyi paste downregulated the mRNA and protein expression of extracellular signal-regulated kinase 1/2 (ERK1/2), and cyclooxygenase-2 (COX-2), and also downregulated the mRNA expression of PGE₂. At the same time, the Zhongyi paste exerted a stronger effect as an external drug than that of indomethacin, which is an oral drug, and voltaren, which is an externally applied drug. Conclusions: Our results indicated that Zhongyi paste is a very effective drug to reduce inflammatory swelling of the foot, and its mechanism of action is related to regulation of the ERK1/2-COX-2-PGE₂ pathway.

• BMB Reports
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• v.50 no.11
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• pp.560-565
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• 2017

Geraniin, a hydrolysable tannin, used in traditional medicine in Southeast Asia, is known to exhibit various biological activities. As an antioxidant it is known to up-regulate phase II enzyme Heme oxygenase-1 (HO-1). However its mechanism is not clearly understood. Nuclear factor erythroid-derived 2 related factor 2 (Nrf-2) is transcriptionally up-regulated by Extracellular signal-regulated kinase (ERK) 1/2 and retained in nucleus due to inactivated Glycogen synthase kinase 3 beta ($GSK-3{\beta}$). Geraniin additionally down-regulates expression of microRNA 217 and 377 (miR-217 and miR-377) which target HO-1 mRNA. Expression of BTB and CNC homolog 1 (BACH-1), another regulator of HO-1, is also down-regulated by up-regulating microRNA 98 (miR-98), a negative regulator of BACH-1. Thus, geraniin up-regulates HO-1 expression both through activating its positive regulator Nrf-2 and by down-regulating its negative regulator BACH-1. Up-regulation of HO-1 also confers protection to HepG2 cells from tertiary butyl hydroperoxide (TBH) induced cytotoxicity.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.58-65
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• 2021

As aging progresses, reactive oxygen species (ROS) reduces skin moisturization and collapses skin barrier function. In this study, we evaluated the efficacy of skin moisturizing and skin barrier function enhancement by extracts from halophytes using HaCaT cells. Spartina anglica (S. anglica; SAE) and Calystegia soldanella (C. soldanella; CSE), a kind of halophytes, were collected from Dongmak beach in Incheon, and extracted with 70% ethanol. At the first, we evaluated the cytotoxicity of extracts in HaCaT cell using WST-8 Kit. As a result, the other experiment was conducted by setting the concentration at which the cell viability was 90% or more. SAE and CSE showed high radical scavenging activity through ABTS assay. Expression levels of genes related to skin moisturizing and skin barrier functions, were analyzed by real-time qPCR. As a result, it showed that the expression of aquaporin 3, hyaluronan synthase 2, and transglutaminase 1 was increased by SAE treatment but not changed by CSE. Activation of extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen activated protein kinase was induced by SAE. These results suggest that SAE can be used as functional materials for cosmetics for skin moisturizing and barrier function enhancement.

• Molecules and Cells
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• v.45 no.7
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• pp.435-443
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• 2022

In response to environmental changes, signaling pathways rewire gene expression programs through transcription factors. Epigenetic modification of the transcribed RNA can be another layer of gene expression regulation. N⁶-adenosine methylation (m⁶A) is one of the most common modifications on mRNA. It is a reversible chemical mark catalyzed by the enzymes that deposit and remove methyl groups. m⁶A recruits effector proteins that determine the fate of mRNAs through changes in splicing, cellular localization, stability, and translation efficiency. Emerging evidence shows that key signal transduction pathways including TGFβ (transforming growth factor-β), ERK (extracellular signal-regulated kinase), and mTORC1 (mechanistic target of rapamycin complex 1) regulate downstream gene expression through m⁶A processing. Conversely, m⁶A can modulate the activity of signal transduction networks via m⁶A modification of signaling pathway genes or by acting as a ligand for receptors. In this review, we discuss the current understanding of the crosstalk between m⁶A and signaling pathways and its implication for biological systems.

• Korean Journal of Veterinary Research
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• v.58 no.1
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• pp.1-7
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• 2018

Genus Artemisia occurs as a hardy plant and has a wide range of culinary and medicinal features. In this study, we aimed to describe the melanin inhibitory activity of one Artemisia species, i.e., Artemisia capillaris Thunb. Ethanol extracts of fermented Artemisia capillaris (Art.EtOH.FT) and non-fermented Artemisia capillaris (Art.EtOH.CT) were tested for their ability to inhibit tyrosinase activity and melanin pigmentation. Both extracts showed dose-dependent inhibition against ${\alpha}$-melanocyte stimulating hormone-stimulated melanin formation and tyrosinase activity, without cytotoxicity. At $100{\mu}g/mL$, both extracts showed greater inhibition than kojic acid, the positive control. Protein expressions of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2) at the transcriptional level were determined by using real-time and semi-quantitative polymerase chain reaction. To complete the mechanistic study, presences of upstream elements of MITF, the phosphorylated-extracellular signal-regulated kinase (p-ERK), and phosphorylated-mitogen-activated protein kinase kinase (p-MEK) were confirmed by using western blot analysis. Expressions of p-TYR, p-TRP-1 and p-TRP-2, downstream factors for p-ERK and p-MITF, were translationally inhibited by both extracts. Art.EtOH.FT induced more potent effects than Art.EtOH.CT, especially signal transduction effects. In summary, Artemisia capillaris extracts appear to act as potent hypopigmentation agents.

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.447-451
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• 2021

In this study, we discovered for the first time that linarin, a flavonoid compound, enhances melanin biosynthesis in B16F10 cells, and subsequently elucidated the underlying mechanism of linarin-induced melanogenesis. Linarin showed no cytotoxicity at a concentration of 42 μM and significantly increased intracellular tyrosinase activity and melanin content in B16F10 cells. Mechanistic analysis showed that linarin increased the expression of tyrosinase, tyrosinase-related protein 1 (TRP-1), and microphthalmia-associated transcription factor (MITF) that are related to melanogenesis. Moreover, linarin decreased the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (AKT). Finally, we evaluated the effect of the structure-activity relationship of linarin and its aglycone on melanogenesis. The results indicated that linarin enhances the expression of melanogenic proteins by activating MITF expression via the modulation of mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and protein kinase B signaling pathways in B16F10 cells, thereby enhancing melanogenesis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.1
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• pp.59-62
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• 2014

Glucose uptake plays a pivotal role in maintaining whole body glucose homeostasis in adipocytes and skeletal muscles. In the present study we have shown that Fructus Piperis Longi Extracts (FPLE) can stimulate glucose uptake in OP9 adipocytes. The increasing effects of FPLE on glucose uptake were inhibited by compound C pretreatment, which means that the glucose uptake effects by FPLE were carried out by AMP-activated protein kinase (AMPK) activation. Further studies revealed that FPLE stimulated glucose transport occurs through a mechanism involving extracellular signal-regulated kinase (ERK1/2) activation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1363-1369
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• 2005

Previously we have shown that shikonin has strong anti-tumor activities via inducing apoptosis and suppressing metastasis on LLC cells in vivo and in vitro. Here we have investigated anti-angiogenic potential of shikonin and its possible mechanism of action in HSE cells. Shikonin inhibited the proliferation of HSE cells in a concentration-dependent manner. It was shown that this proliferation inhibition was caused by apoptosis induced by shikonin via BrdU incorporation and Western blotting analysis. Shikonin treatment was caused that decrease of activation of caspases and cleavage of PARP. And shikonin induced that the activation of mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38. Moreover, shikonin showed anti-angiogenic activities inhibiting tube-like formation of HSE cells in vitro and vascular formation of LLC cells in vivo. These findings suggest that shikonin may a possible candidate not only anti-metastatic agent but also anti-angiogenic agent.

• YAKHAK HOEJI
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• v.54 no.5
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• pp.410-415
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• 2010

We explored the role of phosphodiesterase 4 (PDE4) on parathyroid (PTH)-induced signaling in osteoblasts. PTH was shown to increase the activity of PDE, mainly PDE4, in osteoblasts, which is partly attributable to elevated PDE4B and PDE4D mRNA expression. The use of PDE4 inhibitor strengthened the PTH-induced extracellular signal-regulated kinase (ERK) and p38 MAP kinase (MAPK) activation. Furthermore, the PDE4 inhibitor stimulated PTH-induced receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL) expression in osteoblasts, which in turn increased osteoclast formation. Taken together, these data suggest the negative role of PDE4 on PTH-induced signaling in osteoblasts.