• 한국식품영양학회지
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• 제30권2호
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• pp.312-318
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• 2017

Aloe-emodin (AE) is the major bioactive component in aloe and known to exhibit anti-inflammatory activities. However, it has not been elucidated whether its anti-inflammatory potency can contribute to the elimination of obesity. The aim of the current study is to investigate the effect of AE on toll-like receptor 4 (TLR4) pathways in the presence of lipopolysaccharide (LPS) in 3T3-L1 adipocytes. 3T3-L1 adipocytes were treated with AE ($0-20{\mu}M$) for one hour, followed by LPS treatment for 30 min and then, adipokine mRNA expression levels were measured. Next, TLR4-related molecules were measured in LPS-stimulated 3T3-L1 adipocytes. AE significantly decreased the mRNA expression of the tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) in a dose-dependent manner. Moreover, AE suppressed TLR4 mRNA expression. Further study showed that AE could suppress the nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) and phosphorylation of extracellular receptor-activated kinase (pERK). The results of this study suggest that AE directly inhibits $TLR4/NF-{\kappa}B/ERK$ signaling pathways and decreases the inflammatory response in adipocytes.

• Archives of Pharmacal Research
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• 제26권12호
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• pp.1055-1060
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• 2003

Lysophosphatidic acid (LPA) is a well-known mitogen in various cell types. However, we found that LPA inhibits melanocyte proliferation. Thus, we further investigated the possible signaling pathways involved in melanocyte growth inhibition. We first examined the regulation of the three major subfamilies of mitogen-activated protein (MAP) kinases and of the Akt pathway by LPA. The activations of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) were observed in concert with the inhibition of melanocyte proliferation by LPA, whereas p38 MAP kinase and Akt were not influenced by LPA. However, the specific inhibition of the ERK or JNK pathways by PD98059 or D-JNKI1, respectively, did not restore the antiproliferative effect. We next examined changes in the expression of cell cycle related proteins. LPA decreased cyclin $D_1 and cyclin D_2$ levels but increased $p21^{WAF1/CIP1}$ (p21) and $p27^{KIP1}$ (p27) levels, which are known inhibitors of cyclin-dependent kinase. Flow cytometric analysis showed the inhibition of DNA synthesis by a reduction in the S phase and an increase in the $G_0/G_1$ phase of the cell cycle. Our results suggest that LPA induces cell cycle arrest by regulating the expressions of cell cycle related proteins.

• Biomolecules & Therapeutics
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• 제29권6호
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• pp.615-629
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• 2021

An active compound, triterpene saponin, astersaponin I (AKNS-2) was isolated from Aster koraiensis Nakai (AKNS) and the autophagy activation and neuroprotective effect was investigated on in vitro and in vivo Parkinson's disease (PD) models. The autophagy-regulating effect of AKNS-2 was monitored by analyzing the expression of autophagy-related protein markers in SH-SY5Y cells using Western blot and fluorescent protein quenching assays. The neuroprotection of AKNS-2 was tested by using a 1-methyl-4-phenyl-2,3-dihydropyridium ion (MPP⁺)-induced in vitro PD model in SH-SY5Y cells and an MPTP-induced in vivo PD model in mice. The compound-treated SH-SY5Y cells not only showed enhanced microtubule-associated protein 1A/1B-light chain 3-II (LC3-II) and decreased sequestosome 1 (p62) expression but also showed increased phosphorylated extracellular signal-regulated kinases (p-Erk), phosphorylated AMP-activated protein kinase (p-AMPK) and phosphorylated unc-51-like kinase (p-ULK) and decreased phosphorylated mammalian target of rapamycin (p-mTOR) expression. AKNS-2-activated autophagy could be inhibited by the Erk inhibitor U0126 and by AMPK siRNA. In the MPP⁺-induced in vitro PD model, AKNS-2 reversed the reduced cell viability and tyrosine hydroxylase (TH) levels and reduced the induced α-synuclein level. In an MPTP-induced in vivo PD model, AKNS-2 improved mice behavioral performance, and it restored dopamine synthesis and TH and α-synuclein expression in mouse brain tissues. Consistently, AKNS-2 also modulated the expressions of autophagy related markers in mouse brain tissue. Thus, AKNS-2 upregulates autophagy by activating the Erk/mTOR and AMPK/mTOR pathways. AKNS-2 exerts its neuroprotective effect through autophagy activation and may serve as a potential candidate for PD therapy.

• 대한한의학회지
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• 제29권1호
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• pp.95-105
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• 2008

Objectives : Although herbal medicines containing flavonoids have been reported to exert anti-tumor activities, it has not been explored whether Hwang-Jeong (Polygonati sibirici Rhizoma, PsR) exerts anti-tumor activity in human glioma. The present study was therefore undertaken to examine the effect of PsR on cell viability and to determine its underlying mechanism in A172 human glioma cells. Methods : Cell viability was estimated by MTT assay. Reactive oxygen species generation and mitochondrial membrane potential were measured by the fluorescence dyes. The phosphorylation of kinases was evaluated by western blot analysis and caspase activity was estimated using colorimetric assay kit. Results : PsR resulted in loss of cell viability in a dose- and time-dependent manner. PsR did not increase reactive oxygen species (ROS) generation and the PsR-induced cell death was also not affected by antioxidants, suggesting that ROS generation is not involved in loss of cell viability. Western blot analysis showed that PsR treatment caused rapid reduction in phosphorylation of extracellular signal-regulated kinase (ERK) without changes in p38 and Jun-NH2-terminal kinase (JNK). U0126, an inhibitor of ERK, increased the PsR-induced cell death, but inhibitors of p38 and JNK did not affect the cell death. PsR induced depolarization of mitochondrial membrane potential. Caspase activity was not stimulated by PsR and caspase inhibitors did not prevent the PsR-induced cell death. Conclusion : Taken together, these findings suggest that PsR results in human glioma cell death through caspaseindependent mechanisms involving down-regulation of ERK.

• IMMUNE NETWORK
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• 제5권4호
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• pp.193-198
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• 2005

Background: Protease-activated receptor 2 (PAR2) belongs to a family of G protein coupled receptors activated by proteolytic cleavage. Trypsin-like serine proteases interact with PAR2 expressed by a variety of tissues and immune cells. The aim of our study was to investigate whether PAR2 stimulation can lead to the activation of human mac rophages. Methods: PAR2-mediated proliferation of human macrophage cell line THP-1 was measured with MTT assay. We also examined the extracellular regulated kinase (ERK) phosphorylation and cytokine production induced by trypsin and PAR2-agonist using western blot and enzyme-linked immunosorbent assay (ELISA), respectively. Results: Treatment of trypsin or PAR2-activating peptide increased cell proliferation in a dose-dependent manner, and induced the activation of ERK1/2 in THP-1 cells. In addition, trypsin-induced cell proliferation was inhibited by pretreatment of an ERK inhibitor (pD98059) or trypsin inhibitor (SBTI). Moreover, PAR2 activation by trypsin increased the secretion of TNF-${\alpha}$ in THP-1 cells. Conclusion: There results suggest that P AR2 activation by trypsin-like serine proteases can induce cell proliferation through the activation of ERK in human macrophage and that PAR2 may playa crucial role in the cell proliferation and cytokine secretion induced by trypsin-like serine proteases.

• The Korean Journal of Physiology and Pharmacology
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• 제20권4호
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• pp.347-355
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• 2016

Cryptotanshinone (CPT) is a natural compound isolated from traditional Chinese medicine Salvia miltiorrhiza Bunge. In the present study, the regulatory effect and potential mechanisms of CPT on tumor necrosis factor alpha ($TNF-{\alpha}$) induced lectin-like receptor for oxidized low density lipoprotein (LOX-1) were investigated. Human umbilical vein endothelial cells (HUVECs) were cultured and the effect of $TNF-{\alpha}$ on LOX-1 expression at mRNA and protein levels was determined by Real-time PCR and Western blotting respectively. The formation of intracellular ROS was determined with fluorescence probe $CM-DCFH_2-DA$. The endothelial ox-LDL uptake was evaluated with DiI-ox-LDL. The effect of CPT on LOX-1 expression was also evaluated with SD rats. $TNF-{\alpha}$ induced LOX-1 expression in a dose- and time- dependent manner in endothelial cells. $TNF-{\alpha}$ induced ROS formation, phosphorylation of $NF-{\kappa}B$ p65 and ERK, and LOX-1 expression, which were suppressed by rotenone, DPI, NAC, and CPT. $NF-{\kappa}B$ inhibitor BAY11-7082 and ERK inhibitor PD98059 inhibited $TNF-{\alpha}-induced$ LOX-1 expression. CPT and NAC suppressed $TNF-{\alpha}-induced$ LOX-1 expression and phosphorylation of $NF-{\kappa}B$ p65 and ERK in rat aorta. These data suggested that $TNF-{\alpha}$ induced LOX-1 expression via ROS activated $NF-{\kappa}B/ERK$ pathway, which could be inhibited by CPT. This study provides new insights for the anti-atherosclerotic effect of CPT.

• 동의생리병리학회지
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• 제20권5호
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• pp.1315-1320
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• 2006

The root and rhizomes of Nardostachys chinensis belonging to the family Valerianaceae has been used for medicinal therapy in Korean traditional medicine. The parts have been especially used to elicit stomachic and sedative effects. Our previous studies reported that the water extract of N. chinensis has induced granulocytic differentiation inhuman promyelocytic leukemia (HL-60) cells. The Mitogen-activated protein kinases (MAPKs) are serine/threonine kinases involved in the regulation of various cellular responses, such as cell proliferation, differentiation and apoptosis. In this study, we investigated the signaling pathways on the HL-60 cell differentiation induced by N. chinensis. Activation of extracellular signal-regulated kinase (ERK) increased time-dependently in differentiation of HL-60 cells induced by N. chinersis. Activation of p38 increased slightly at 24 h after N. chinensis treatment, but activation of c-jun N-terminal kinase (JNK) was unaffected. Inhibitor of ERK (PD98059) significantly reduced NBT reduction activity induced by N. chinensis in HL-60 cells. In contrast, p38 inhibitor (SB203580) did not inhibit the cell differentiation. These results indicated that activaiton of ERK may De involved in HL-60 cell differentiation induced by N. chinensis.

• Animal cells and systems
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• 제16권3호
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• pp.190-197
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• 2012

Depression is one of the most prevalent diseases of alcohol abuse. Brain-derived neurotrophic factor (BDNF) plays a critical role in cell survival in the hippocampus. Phosphorylation of extracellular signal-regulated kinase 1/2 (p-ERK1/2) is induced by BDNF, and it regulates cell proliferation and differentiation in the brain. We investigated the effects of alcohol intake on depression-like behavior, cell proliferation, expressions of BDNF and its downstream molecules in the hippocampus using Mongolian gerbils. The gerbils were divided into four groups: control group, 0.5 g/kg alcohol-treated group, 1 g/kg alcohol-treated group, 2 g/kg alcohol-treated group. Each dose of alcohol was orally administered for 3 weeks. The present results demonstrated that alcohol intake induced depression-like behavior. Both 5-hydroxytryptamine synthesis and its synthesizing enzyme tryptophan hydroxylase expression in the dorsal raphe and cell proliferation in the hippocampal dentate gyrus were decreased by alcohol intake. Alcohol intake suppressed BDNF expression, and resulted in the decrease of its downstream molecules, pERK1/2 and Bcl-2, in the hippocampus. We showed that alcohol intake may lead to a depressed-like state with reduced hippocampal cell proliferation through inhibition of the BDNF-ERK signaling pathway.

• 한방안이비인후피부과학회지
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• 제31권1호
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• pp.12-21
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• 2018

Objectives : Inflammation is one of the self-protective abilities against tissue injury, and it has clinical symptoms like redness, heat, swelling, pain, and loss of function. The purpose of this study is to examine inhibitory effects of Naetakchunkeum-san (NTCKS) on nitric oxide (NO), Prostaglandin E2 (PGE2), inducible NOS (iNOS), cyclooxygenase-2 (COX-2), and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), which play a major role in inflammatory response. Methods : The experiment was performed using Raw 264.7 cells pretreated with NTCKS extracts. Cell viability was determined by MTT assay. To evaluate anti-inflammatory effects of NTCKS, we examined NO and $PGE_2$ production in LPS-induced macrophages. We also investigated effects of NTCKS on iNOS, Cox-2, and ERK1/2 expression using western blot. Results : In MTT assay, no cytotoxicity of NTCKS (50, 100, 150, $200{\mu}g/ml$) on RAW 264.7 cell was found. LPS-induced NO production was decreased after treatment with NTCKS (150, $200{\mu}g/ml$)(p<0.05). $PGE_2$ was decreased after treatment with NTCKS (150, $200{\mu}g/ml$)(p<0.05). NTCKS inhibited LPS-induced expressions of iNOS and COX-2 in a dose-dependent manner. Increased phosphorylation of ERK1/2 by LPS was decreased by NTCKS in a dose-dependent manner. Conclusions : According to above experiments, NTCKS may be applied to inflammatory diseases such as atopic dermatitis, rheumatoid arthritis, and inflammatory bowel disease.

• BMB Reports
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• 제46권7호
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• pp.352-357
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• 2013

Atherosclerosis, which manifests as acute coronary syndrome, stroke, and peripheral arterial diseases, is a chronic inflammatory disease of the arterial wall. Prunella vulgaris, a perennial herb with a worldwide distribution, has been used as a traditional medicine in inflammatory disease. Here, we investigated the effects of P. vulgaris ethanol extract on TNF-${\alpha}$-induced inflammatory responses in human aortic smooth muscle cells (HASMCs). We found that P. vulgaris ethanol extract inhibited adhesion of monocyte/macrophage-like THP-1 cells to activated HASMCs. It also decreased expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin and ROS, No production in TNF-${\alpha}$-induced HASMCs and reduced NF-${\kappa}B$ activation. Furthermore, P. vulgaris extract suppressed TNF-${\alpha}$-induced phosphorylation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK). These results demonstrate that P. vulgaris possesses anti-inflammatory properties and can regulate TNF-${\alpha}$-induced expression of adhesion molecules by inhibiting the p38 MAPK/ERK signaling pathway.