• Title/Summary/Keyword: Intracellular signaling

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Regulation of toll-like receptors expression in muscle cells by exercise-induced stress

  • Park, Jeong-Woong;Kim, Kyung-Hwan;Choi, Joong-Kook;Park, Tae Sub;Song, Ki-Duk;Cho, Byung-Wook
    • Animal Bioscience
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    • v.34 no.10
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    • pp.1590-1599
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    • 2021
  • Objective: This study investigates the expression patterns of toll-like receptors (TLRs) and intracellular mediators in horse muscle cells after exercise, and the relationship between TLRS expression in stressed horse muscle cells and immune cell migration toward them. Methods: The expression patterns of the TLRs (TLR2, TLR4, and TLR8) and downstream signaling pathway-related genes (myeloid differentiation primary response 88 [MYD88]; activating transcription factor 3 [ATF3]) are examined in horse tissues, and horse peripheral blood mononuclear cells (PBMCs), polymorphonuclear cells (PMNs) and muscles in response to exercise, using the quantitative reverse transcription-polymerase chain reaction (qPCR). Expressions of chemokine receptor genes, i.e., C-X-C motif chemokine receptor 2 (CXCR2) and C-C motif chemokine receptor 5 (CCR5), are studied in PBMCs and PMNs. A horse muscle cell line is developed by transfecting SV-T antigen into fetal muscle cells, followed by examination of muscle-specific genes. Horse muscle cells are treated with stressors, i.e., cortisol, hydrogen peroxide (H2O2), and heat, to mimic stress conditions in vitro, and the expression of TLR4 and TLR8 are examined in stressed muscle cells, in addition to migration activity of PBMCs toward stressed muscle cells. Results: The qPCR revealed that TLR4 message was expressed in cerebrum, cerebellum, thymus, lung, liver, kidney, and muscle, whereas TLR8 expressed in thymus, lung, and kidney, while TLR2 expressed in thymus, lung, and kidney. Expressions of TLRs, i.e., TLR4 and TLR8, and mediators, i.e., MYD88 and ATF3, were upregulated in muscle, PBMCs and PMNs in response to exercise. Expressions of CXCR2 and CCR5 were also upregulated in PBMCs and PMNs after exercise. In the muscle cell line, TLR4 and TLR8 expressions were upregulated when cells were treated with stressors such as cortisol, H2O2, and heat. Migration of PBMCs toward stressed muscle cells was increased by exercise and oxidative stresses, and combinations of these. Treatment with methylsulfonylmethane (MSM), an antioxidant on stressed muscle cells, reduced migration of PBMCs toward stressed muscle cells. Conclusion: In this study, we have successfully cultured horse skeletal muscle cells, isolated horse PBMCs, and established an in vitro system for studying stress-related gene expressions and function. Expression of TLR4, TLR8, CXCR2, and CCR5 in horse muscle cells was higher in response to stressors such as cortisol, H2O2, and heat, or combinations of these. In addition, migration of PBMCs toward muscle cells was increased when muscle cells were under stress, but inhibition of reactive oxygen species by MSM modulated migratory activity of PBMCs to stressed muscle cells. Further study is necessary to investigate the biological function(s) of the TLR gene family in horse muscle cells.

Protective Role of Transduced Tat-Thioredoxin1 (Trx1) against Oxidative Stress-Induced Neuronal Cell Death via ASK1-MAPK Signal Pathway

  • Yeo, Eun Ji;Eum, Won Sik;Yeo, Hyeon Ji;Choi, Yeon Joo;Sohn, Eun Jeong;Kwon, Hyun Jung;Kim, Dae Won;Kim, Duk-Soo;Cho, Sung-Woo;Park, Jinseu;Han, Kyu Hyung;Lee, Keun Wook;Park, Jong Kook;Shin, Min Jea;Choi, Soo Young
    • Biomolecules & Therapeutics
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    • v.29 no.3
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    • pp.321-330
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    • 2021
  • Oxidative stress plays a crucial role in the development of neuronal disorders including brain ischemic injury. Thioredoxin 1 (Trx1), a 12 kDa oxidoreductase, has anti-oxidant and anti-apoptotic functions in various cells. It has been highly implicated in brain ischemic injury. However, the protective mechanism of Trx1 against hippocampal neuronal cell death is not identified yet. Using a cell permeable Tat-Trx1 protein, protective mechanism of Trx1 against hydrogen peroxide-induced cell death was examined using HT-22 cells and an ischemic animal model. Transduced Tat-Trx1 markedly inhibited intracellular ROS levels, DNA fragmentation, and cell death in H2O2-treatment HT-22 cells. Tat-Trx1 also significantly inhibited phosphorylation of ASK1 and MAPKs in signaling pathways of HT-22 cells. In addition, Tat-Trx1 regulated expression levels of Akt, NF-κB, and apoptosis related proteins. In an ischemia animal model, Tat-Trx1 markedly protected hippocampal neuronal cell death and reduced astrocytes and microglia activation. These findings indicate that transduced Tat-Trx1 might be a potential therapeutic agent for treating ischemic injury.

Anti-oxidant and Anti-inflammatory Effects of Ethanol Extracts from Leonurus japonicus Houtt. on LPS-induced RAW 264.7 Cells (익모초 에탄올 추출물의 항산화 및 항염증 활성)

  • Choi, You-Na;Choi, Yu-Kyung;Nan, Li;Choo, Byung-Kil
    • Korean Journal of Organic Agriculture
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    • v.28 no.4
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    • pp.659-677
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    • 2020
  • Leonurus japonicus (L. japonicus) Houtt., a biennial plant in the Lamiaceae family is broadly distributed in Asia such as Korea, China, Japan. The aerial part of L. japonicus is used as a traditional medicine to treat uterine disease including dysmenorrhea, amenorrhea, sterility. In this study, we examined the antioxidant and anti-inflammatory effects of L. japonicus ethanol extracts. The antioxidant activity of L. japonicus was measured by total polyphenol and flavonoid content, and DPPH, ABTS scavenging, reducing power activity, and intracellular ROS expression assay. The anti-inflammatory effects were measured by nitric oxide (NO), cytokines (TNF-α and IL-1β) production and inflammatory protein expression in LPS-induced RAW 264.7 cells. Total polyphenol and flavonoid content of L. japonicus were 51.40 ± 0.47 mg of gallic acid equivalents/g and 73.28 ± 0.10 mg of rutin equivalents/g respectively. DPPH, ABTS radical scavenging activity and reducing power activity tended to increase concentration-dependent and treatment L. japonicus with 400 ㎍/mL reduced ROS production by 69.5%. Furthermore, L. japonicus inhibited NO, TNF-α and IL-1β production in a concentration-dependant manner and reduced the expression levels of inflammatory proteins via regulating NF-κB, MAPK pathway. Therefore, we suggest that L. japonicus could be a natural antioxidants and medicinal source to treat oxidative stress and inflammation-related disease.

Red ginseng-derived saponin fraction inhibits lipid accumulation and reactive oxygen species production by activating nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) pathway (홍삼 사포닌 분획의 Nrf2 Keap1 신호전달체계 조절을 통한 지방축적 및 활성산소종 억제효과)

  • Kim, Chae-Young;Kang, Bobin;Hwang, Jisu;Choi, Hyeon-Son
    • Korean Journal of Food Science and Technology
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    • v.50 no.6
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    • pp.688-696
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    • 2018
  • This study aimed to investigate the effects of red ginseng-derived saponin fraction (SF) on lipid accumulation, reactive oxygen species (ROS) production, and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) signaling during adipocyte differentiation. SF effectively inhibited lipid accumulation, with the downregulation of adipogenic factors such as peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) and CCAAT/enhancer-binding protein alpha ($C/EBP{\alpha}$). A high dose of SF decreased the protein levels of $PPAR{\gamma}$ and $C/EBP{\alpha}$ by over 90% compared to the control. SF-mediated downregulation of adipogenic factors was due to the regulation of early adipogenic factors including $C/EBP{\beta}$ and $Kr{\ddot{u}}ppel$-like Factor 2 (KLF2). In addition, SF ($200{\mu}g/mg$) decreased intracellular ROS generation by 40% during adipocyte differentiation. However, the SF significantly upregulated Nrf2 and its target proteins, hemoxygenase-1 (HO-1) and NADPH dehydrogenase quinone 1 (NQO1). Furthermore, SF ($200{\mu}g/mg$) promoted the nuclear translocation of Nrf2. The SF-mediated reduction of lipid accumulation was associated with the regulation of the Nrf2/Keap1 pathway.

Effects of Piperine on Insulin Resistance and Lipid Accumulation in Palmitate-treated HepG2 Cells (Palmitate처리된 인간 간세포주 HepG2 세포에서 piperine의 지질 축적과 인슐린 저항성 기전에 대한 연구)

  • Jung, Hee Jin;Bang, EunJin;Jeong, Seong Ho;Kim, Byeong Moo;Chung, Hae Young
    • Journal of Life Science
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    • v.29 no.9
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    • pp.964-971
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    • 2019
  • Hepatic lipid accumulation and insulin resistance increases in patients with non-alcoholic fatty liver disease. Piperine is a major compound found in black pepper (Piper nigrum) and long pepper (P. longum). Piperine has been used in fine chemical for its anti-cancer, anti-obesity, anti-diabetic, anti-inflammatory and anti-oxidant properties. However, the signaling-based mechanism of piperine and its role as an inhibitor of lipogenesis and insulin resistance in human hepatocyte cells remains ill-defined. In the present study, we explored the effects of piperine on lipid accumulation and insulin resistance, and explored the potential underlying molecular mechanisms in palmitate-treated HepG2 cells. Piperine treatment resulted in a significant reduction of triglyceride content. Furthermore, piperine treatment decreased palmitate-treated intracellular lipid deposition by inhibiting the lipogenic target genes, sterol-regulatory-element-binding protein 1c (SREBP-1c) and fatty acid synthase (FAS); whereas the expression of carnitine palmitoyl transferase (CPT-1) and phosphorylation of acetyl coenzyme A carboxylase (ACC) gene involved in fatty acid oxidation was increased. Moreover, piperine also inhibited the phosphorylation of insulin receptor substrate (IRS)-1 (Ser307). Piperine treatment modulated palmitate-treated lipid accumulation and insulin resistance in HepG2 cells with concomitant reduction of lipogenic target genes, such as SREBP-1 and FAS, and induction of CPT-1-ACC and phosphorylation of IRS-1 (Tyr632)-Akt pathways. Therefore, piperine represents a promising treatment for the prevention of lipid accumulation and insulin resistance.

Cudrania tricuspidata Fruit Extract Ameliorates Free Fatty Acid-induced Lipid Accumulation in HepG2 Cells (유리지방산으로 지방축적을 유도한 HepG2 cells 대한 꾸지뽕 열매 추출물의 개선 효과)

  • Lee, Hyo-Jeong;Park, Se-Eun;Kim, Seung
    • Journal of Life Science
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    • v.29 no.10
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    • pp.1144-1151
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    • 2019
  • Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease associated with various metabolic syndromes, such as obesity, dyslipidemia, hypertension, and diabetes. Cudrania tricuspidata is a medicinal plant distributed widely in Asia and has been used in clinical practice to treat various diseases. The aim of this study is to determine the lipid-lowering effects of C. tricuspidata fruit extract (CTE) using a cell model induced by free fatty acids (FFAs). HepG2 cells were exposed to 1mM FFAs (palmitic acid:oleic acid = 2:1) for 24 hr to simulate the conditions of NAFLD in vitro. CTE attenuated the increases of lipid accumulation, intracellular triglyceride, and cholesterol content and inhibited 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) activity in the HepG2 cells in a dose-dependent manner. Also, CTE inhibited the protein expression of lipogenesis-related genes, such as sterol regulatory element-binding protein-1/-2 (SREBP-1/-2), fatty acid synthase (FAS), and stearoyl CoA desaturase-1 (SCD-1) in FFAs-induced lipid accumulation in HepG2 cells. In addition, CTE-induced adenosine monophosphate-activated protein kinase (AMPK) phosphorylation in HepG2 cells. These results suggest that CTE attenuates hepatic lipid accumulation by inhibiting lipogenesis through the modulation of the AMPK signaling pathway on FFAs-induced lipogenesis in HepG2 cells and may potentially prevent NAFLD.

Gene Expression Profiling by Ginsenoside Rb1 in Keratinocyte HaCaT Cells (피부각질세포 HaCaT에서 진세노사이드 Rb1에 의한 유전자 발현 양상)

  • Lee, Dong Woo;Kim, Jung Min;Bang, In Seok
    • Journal of Life Science
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    • v.29 no.5
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    • pp.514-523
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    • 2019
  • We investigated the gene expression patterns and the mechanisms of action of the apoptotic response by microarray analysis of human keratinocyte HaCaT cells treated with ginsenoside Rb1, a saponin of Panax ginseng C. A. Meyer. Genes related to apoptosis, the G2/M transition of the mitotic cell cycle, cell division, mitotic nuclear division, and intracellular protein transport were 2-fold up-regulated in HaCaT cells treated with the ginsenoside Rb1, whereas genes related to DNA repair, regeneration fission, and extracellular matrix organization were 2-fold down-regulated. Apoptosis signaling may be mediated by FAS and PLA2G4A, and pathway analysis indicated that STAT3 might be an upstream regulator of these genes. The activity of FAS and PLA2G4A was verified by qPCR, which showed that FAS was increased about 2-fold in HaCaT cells treated with $10{\mu}g/ml$ of ginsenoside Rb1 for 24 hr, PLA2G4A was increased about twice after 6 hours, and gene expression was increased more than 2-fold after 24 hr. Knockdown of STAT3 with siRNA decreased FAS expression and increased PLA2G4A expression but only FAS was passed from the upstream regulator STAT3. These results indicate that STAT3, which is an upstream regulator, induces apoptosis via FAS during treatment with ginsenoside Rb1.

Gintonin-mediated release of astrocytic vascular endothelial growth factor protects cortical astrocytes from hypoxia-induced cell damages

  • Choi, Sun-Hye;Kim, Hyeon-Joong;Cho, Hee-Jung;Park, Sang-Deuk;Lee, Na-Eun;Hwang, Sung-Hee;Rhim, Hyewon;Kim, Hyoung-Chun;Cho, Ik-Hyun;Nah, Seung-Yeol
    • Journal of Ginseng Research
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    • v.43 no.2
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    • pp.305-311
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    • 2019
  • Background: Gintonin is a ginseng-derived exogenous ligand of the G protein-coupled lysophosphatidic acid (LPA) receptor. We previously reported that gintonin stimulates gliotransmitter release in primary cortical astrocytes. Astrocytes play key roles in the functions of neurovascular systems. Although vascular endothelial growth factor (VEGF) is known to influence the normal growth and maintenance of cranial blood vessels and the nervous system, there is little information about the effect of gintonin on VEGF regulation in primary astrocytes, under normal and hypoxic conditions. Methods: Using primary cortical astrocytes of mice, the effects of gintonin on the release, expression, and distribution of VEGF were examined. We further investigated whether the gintonin-mediated VEGF release protects astrocytes from hypoxia. Results: Gintonin administration stimulated the release and expression of VEGF from astrocytes in a concentration- and time-dependent manner. The gintonin-mediated increase in the release of VEGF was inhibited by the LPA1/3 receptor antagonist, Ki16425; phospholipase C inhibitor, U73122; inositol 1,4,5- triphosphate receptor antagonist, 2-APB; and intracellular $Ca^{2+}$ chelator, BAPTA. Hypoxia further stimulated astrocytic VEGF release. Gintonin treatment stimulated additional VEGF release and restored cell viability that had decreased due to hypoxia, via the VEGF receptor pathway. Altogether, the regulation of VEGF release and expression and astrocytic protection mediated by gintonin under hypoxia are achieved via the LPA receptor-VEGF signaling pathways. Conclusion: The present study shows that the gintonin-mediated regulation of VEGF in cortical astrocytes might be neuroprotective against hypoxic insults and could explain the molecular basis of the beneficial effects of ginseng on the central nervous system.

A Novel Heptapeptide that Promotes Cellular Activity and Inhibits Photoaging in Fibroblasts (섬유아세포에서 세포 활성 촉진 및 광노화 억제 효능을 보이는 신규 헵타펩타이드)

  • Lee, Eung Ji;Kang, Hana;Hwang, Bo Byeol;Chung, Yong Ji;Kim, Eun Mi
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.48 no.2
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    • pp.157-167
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    • 2022
  • In this study, we investigated the effects of heptapeptide on cellular activation and inhibition of cellular damage induced by photoaging condition in NIH3T3 fibroblasts. Cell proliferation and extracellular matrix (ECM) expression were induced by heptapeptide. The reduced cell viability under photoaging condition through ultraviolet A (UVA) irradiation was increased by heptapeptide. And UVA-induced apoptosis, matrix metalloproteinases-1 (MMP-1) expression, and reactive oxygen species (ROS) level were decreased by heptapeptide. In addition, the inhibition of transforming growth factor-β (TGF-β)/smad signaling under UVA irradiation which resulting in reduction of ECM expression was also recovered by heptapeptide. We also tested the effect of heptapeptide under another photoaging condition through heat shock, and pre-treatment of heptapeptide prevented the phosphorylation of mitogen-activated protein kinase (MAPK) and MMP-1 expression induced by heat shock. From these results, it has been shown that the heptapeptide has protective effects on fibroblasts through the up-regulation of cellular activity and through the decreasing of intracellular ROS level induced by UVA irradiation or heat shock. It is expected that the dermal protection effect of heptapeptide can be applied as a new cosmetic material in the future.

The TGFβ→TAK1→LATS→YAP1 Pathway Regulates the Spatiotemporal Dynamics of YAP1

  • Min-Kyu Kim;Sang-Hyun Han;Tae-Geun Park;Soo-Hyun Song;Ja-Youl Lee;You-Soub Lee;Seo-Yeong Yoo;Xin-Zi Chi;Eung-Gook Kim;Ju-Won Jang;Dae Sik Lim;Andre J. van Wijnen;Jung-Won Lee;Suk-Chul Bae
    • Molecules and Cells
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    • v.46 no.10
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    • pp.592-610
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    • 2023
  • The Hippo kinase cascade functions as a central hub that relays input from the "outside world" of the cell and translates it into specific cellular responses by regulating the activity of Yes-associated protein 1 (YAP1). How Hippo translates input from the extracellular signals into specific intracellular responses remains unclear. Here, we show that transforming growth factor β (TGFβ)-activated TAK1 activates LATS1/2, which then phosphorylates YAP1. Phosphorylated YAP1 (p-YAP1) associates with RUNX3, but not with TEAD4, to form a TGFβ-stimulated restriction (R)-point-associated complex which activates target chromatin loci in the nucleus. Soon after, p-YAP1 is exported to the cytoplasm. Attenuation of TGFβ signaling results in re-localization of unphosphorylated YAP1 to the nucleus, where it forms a YAP1/TEAD4/SMAD3/AP1/p300 complex. The TGFβ-stimulated spatiotemporal dynamics of YAP1 are abrogated in many cancer cells. These results identify a new pathway that integrates TGFβ signals and the Hippo pathway (TGFβ→TAK1→LATS1/2→YAP1 cascade) with a novel dynamic nuclear role for p-YAP1.