• Biomolecules & Therapeutics
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• v.24 no.4
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• pp.387-394
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• 2016

Sepsis, a serious clinical problem, is characterized by a systemic inflammatory response to infection and leads to organ failure. Toll-like receptor (TLR) signaling is intimately implicated in hyper-inflammatory responses and tissue injury during sepsis. Histone deacetylase (HDAC) inhibitors have been reported to exhibit anti-inflammatory properties. The aim of this study was to investigate the hepatoprotective mechanisms of trichostatin A (TSA), a HDAC inhibitor, associated with TLR signaling pathway during sepsis. The anti-inflammatory properties of TSA were assayed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Polymicrobial sepsis was induced in mice by cecal ligation and puncture (CLP), a clinically relevant model of sepsis. The mice were intraperitoneally received TSA (1, 2 or 5 mg/kg) 30 min before CLP. The serum and liver samples were collected 6 and 24-h after CLP. TSA inhibited the increased production of tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-6 in LPS-stimulated RAW264.7 cells. TSA improved sepsis-induced mortality, attenuated liver injury and decreased serum TNF-${\alpha}$ and IL-6 levels. CLP increased the levels of TLR4, TLR2 and myeloid differentiation primary response protein 88 (MyD88) protein expression and association of MyD88 with TLR4 and TLR2, which were attenuated by TSA. CLP increased nuclear translocation of nuclear factor kappa B and decreased cytosolic inhibitor of kappa B ($I{\kappa}B$) protein expression, which were attenuated by TSA. Moreover, CLP decreased acetylation of $I{\kappa}B$ kinase (IKK) and increased association of IKK with $I{\kappa}B$ and TSA attenuated these alterations. Our findings suggest that TSA attenuates liver injury by inhibiting TLR-mediated inflammatory response during sepsis.

• Biomolecules & Therapeutics
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• v.24 no.1
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• pp.40-48
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• 2016

The pregnane X receptor (PXR), a liver and intestine specific receptor,, has been reported to be related with the repression of inflammation as well as activation of cytochromosome P450 3A (CYP3A) expression. We examined the effect of PXR on tetrachloromethane (CCl4)-induced mouse liver inflammation in this work. Ginkgolide A, one main component of Ginkgo biloba extracts (GBE), activated PXR and enhanced PXR expression level, displayed both significant therapeutic effect and preventive effect against $CCl_4$-induced mouse hepatitis. siRNA-mediated decrease of PXR expression significantly reduced the efficacy of Ginkgolide A in treating $CCl_4$-induced inflammation in mice. Flavonoids, another important components of GBE, were shown anti-inflammatory effect in a different way from Ginkgolide A which might be independent on PXR because flavonoids significantly inhibited CYP3A11 activities in mice. The results indicated that anti-inflammatory effect of PXR might be mediated by enhancing transcription level of $I{\kappa}B{\alpha}$ through binding of $I{\kappa}B{\alpha}$. Inhibition of NF-${\kappa}B$ activity by NF-${\kappa}B$-specific suppressor $I{\kappa}B{\alpha}$ is one of the potential mechanisms of Ginkgolide A against CCl4-induced liver inflammation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.267-272
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• 2017

Piceatannol (PIC) is a natural hydroxylated analog of resveratrol (RSV), which is a polyphenol known to extend lifespan by stimulating sirtuins. The aim of this study was to investigate the effects of PIC and RSV on the toll-like receptor 4 (TLR4)-nuclear factor kappa B ($NF-{\kappa}B$) pathway in mouse hepatocytes and an obese/diabetic KK/HlJ mouse model. AML12 mouse hepatocytes in the absence or presence of palmitic acids (PA) were treated with PIC ($50{\mu}M$) or RSV ($50{\mu}M$). Male KK/HlJ mice at 20 weeks of age were divided into three subgroups as follows: 1) obese and diabetic control (KK), 2) KK_PIC, and 3) KK_RSV. PIC and RSV were administered orally at a dose of 10 mg/kg/d for 4 weeks. Four weeks of PIC and RSV treatment did not affect body weight or food intake in KK mice. Serum fasting blood glucose was significantly reduced in KK_PIC, and 2 h oral glucose tolerance test area under the curve was significantly reduced by PIC and RSV treatment in KK mice. PIC tended to improve homeostasis model assessment of the insulin resistance index (HOMA-IR) and HOMA beta-cells in diabetic KK mice. TLR4 and $NF-{\kappa}B$ were down-regulated by PIC and RSV treatments in hepatocytes in the absence or presence of PA. Insulin receptor, AMP-activated protein kinase, peroxisome proliferator-activated receptor gamma, nucleotide oligomerization domain-like receptor family pyrin domain-containing 3, interleukin-1, and $NF-{\kappa}B$ were altered in PIC-treated livers. Collectively, PIC and RSV inhibited the $TLR4-NF-{\kappa}B$ pathway, and PIC seems to be more effective than RSV in the regulation of analyzed targets, which are involved in insulin signaling and inflammation in vivo.

• Journal of Acupuncture Research
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• v.29 no.1
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• pp.25-35
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• 2012

목적 : 이 연구는 $Vipera$ $lebetina$ $turanica$ 사독(蛇毒)이 인간 대장암 세포주인 HCT116 세포에서 세포주기진행, death receptor 의존적 세포자멸사 경로 관련단백질 발현 및 NK-${\kappa}B$와 STAT3 활성에 미치는 영향을 규명함으로써 대장암 세포 성장에 대한 억제와 그 기전에 대하여 살펴보고자 하였다. 방법 : 사독을 처리한 후 HCT116의 세포주기를 분석하기 위해서 FACS analysis를 시행하였고, apoptosis 평가에는 TUNEL assay를 시행하였으며 death receptor 의존적 세포자멸사 경로 관련단백질 및 NF-${\kappa}B$와 STAT3 활성 변동 관찰에는 RT-PCR 및 western blot analysis를 시행하였다. 결과 : 1. 0.1, 0.5 및 $1{\mu}g/m{\ell}$ 등의 사독을 처리한 결과 농도 의존적으로 HCT116 대장암 세포활성의 억제가 나타났다. 2. 0.1, 0.5 및 $1{\mu}g/m{\ell}$ 등의 사독을 처리한 결과 농도의존적으로 세포자멸사 활성세포의 증가가 나타났고, SVT $1{\mu}g/m{\ell}$에서는 60-70%의 대장암세포 억제 효과가 나타났다. 3. 0.1, 0.5 및 $1{\mu}g/m{\ell}$ 등의 사독을 처리한 결과 약한 G1 arrest와 강한 G2/M arrest가 나타났고, G0/G1 또는 G2/M 관련 cyclin D, E 및 B1의 증가가 나타났다. 4. 0.1, 0.5 및 $1{\mu}g/m{\ell}$ 등의 사독을 처리한 결과 death receptor4, 5의 발현증가와 그에 따른 세포자멸사 촉진 Bax, PARP, caspase-3, -8, -9 발현 증가 및 세포자멸사 억제의 Bcl-2의 발현 감소 등이 나타났다. 6. 0.1, 0.5 및 $1{\mu}g/m{\ell}$ 등의 사독을 처리한 결과 NF-${\kappa}B$와 STAT3의 활성변동은 관찰되지 않았다. 결론 : 이상의 연구에서 사독은 death receptor 의존적인 세포자멸사를 촉진하여 대장암의 화학치료 내성을 극복할 수 있는 하나의 대안이 될 것으로 생각되지만 보다 심화된 연구가 필요할 것으로 사료된다.

• Journal of Microbiology
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• v.37 no.4
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• pp.256-262
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• 1999

Latent membrane protein 1 (LMP1) of the Epstein-Barr virus (EBV) is an integral membrane protein with six transmembrane domains, which is essential for EBV-induced B cell transformation. LMP1 functions as a constitutively active tumor necrosis factor receptor (TNFR) like membrane receptor, whose signaling requires recruitment of TNFR-associated factors (TRAFs) and leads to NF-${\kappa}B$ activation. NF-${\kappa}B$ activation by LMP1 is critical for B cell transformation and has been linked to many phenotypic changes associated with EBV-induced B cell transformation. Deletion analysis has identified two NF-${\kappa}B$ activation regions in the carboxy terminal cytoplasmic domains of LMP1, termed CTAR1 (residues 194-232) and CTAR2 (351-386). The membrane proximal C-terminal domain was precisely mapped to a PXQXT motif (residues 204-208) involved in TRAF binding as well as NF-${\kappa}B$ activation. In this study, we dissected the CTAR2 region, which is the major NF-${\kappa}B$ signaling effector of LMP1, to determine a minimal functional sequence. A series of LMP1 mutant constructs systematically deleted for the CTAR2 region were prepared, and NF-${\kappa}B$ activation activity of these mutants were assessed by transiently expressing them in 293 cells and Jurkat T cells. The NF-${\kappa}B$ activation domain of CTAR2 appears to reside in a stretch of 6 amino acids (residues 379-384) at the end of the carboxy terminus.

• International Journal of Oral Biology
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• v.38 no.3
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• pp.121-126
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• 2013

Tumor necrosis factor alpha ($TNF{\alpha}$) is a multifunctional inflammatory cytokine that regulates various cellular and biological processes. Increased levels of $TNF{\alpha}$ have been implicated in a number of human diseases including diabetes and arthritis. Sympathetic nervous system stimulation via the beta2-adrenergic receptor (${\beta}2AR$) in osteoblasts suppresses osteogenic activity. We previously reported that $TNF{\alpha}$ upregulates ${\beta}2AR$ expression in murine osteoblastic cells and that this modulation is associated with $TNF{\alpha}$ inhibition of osteoblast differentiation. In our present study, we explored whether $TNF{\alpha}$ induces ${\beta}2AR$ expression in human osteoblasts and then identified the downstream signaling pathway. Our results indicated that ${\beta}2AR$ expression was increased in Saos-2 and C2C12 cells by $TNF{\alpha}$ treatment, and that this increase was blocked by the inhibition of NF-${\kappa}B$ activation. Chromatin immunoprecipitation and luciferase reporter assay results indicated that NF-${\kappa}B$ directly binds to its cognate elements on the ${\beta}2AR$ promoter and thereby stimulates ${\beta}2AR$ expression. These findings suggest that the activation of $TNF{\alpha}$ signaling in osteoblastic cells leads to an upregulation of ${\beta}2AR$ and also that $TNF{\alpha}$ induces ${\beta}2AR$ expression in an NF-${\kappa}B$-dependent manner.

• Biomedical Science Letters
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• v.23 no.4
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• pp.295-302
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• 2017

Mononuclear osteoclast precursors derived from hematopoietic progenitors fuse together and then become multinucleated mature osteoclasts by macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL). Especially, the binding of RANKL to its receptor RANK provides key signals for osteoclast differentiation and bone-resorbing function. RANK transduces intracellular signals by recruiting adaptor molecules such as TNFR-associated factors (TRAFs), which then activate mitogen activated protein kinases (MAPKs), Src/PI3K/Akt pathway, nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and finally amplify NFATc1 activation for the transcription and activation of osteoclast marker genes. This review will briefly describe RANKL-RANK signaling pathways and key molecules critical for osteoclast differentiation.

• Journal of Ginseng Research
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• v.37 no.3
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• pp.261-268
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• 2013

The ginseng plant (Panax ginseng Meyer) has a large number of active ingredients including steroidal saponins with a dammarane skeleton as well as protopanaxadiol and protopanaxatriol, commonly known as ginsenosides, which have antioxidant, anticancer, antidiabetic, anti-adipocyte, and sexual enhancing effects. Though several discoveries have demonstrated that ginseng saponins (ginsenosides) as the most important therapeutic agent for the treatment of osteoporosis, yet the molecular mechanism of its active metabolites is unknown. In this review, we summarize the evidence supporting the therapeutic properties of ginsenosides both in vivo and in vitro, with an emphasis on the different molecular agents comprising receptor activator of nuclear factor kappa-B ligand, receptor activator of nuclear factor kappa-B, and matrix metallopeptidase-9, as well as the bone morphogenetic protein-2 and Smad signaling pathways.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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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.

• Molecules and Cells
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• v.26 no.5
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• pp.486-489
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• 2008

Curcumin (diferuloylmethane), a pigment derived from turmeric, has anti-oxidant and anti-inflammatory activities. Accumulating evidence points to a biochemical link between increased oxidative stress and reduced bone density. Osteoclast formation was evaluated in co-cultures of bone marrow stromal cells (BMSC) and whole bone marrow cells (BMC). Expression of receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL) was analyzed at the mRNA and protein levels. Exposure to curcumin led to dose-dependent suppression of osteoclastogenesis in the co-culture system, and to reduced expression of RANKL in $IL-1{\alpha}$-stimulated BMSCs. Addition of RANKL abolished the inhibition of osteoclastogenesis by curcumin, whereas the addition of prostaglandin $E_2$ ($PGE_2$) did not. The decreased osteoclastogenesis induced by curcumin may reduce bone loss and be of potential benefit in preventing and/or attenuating osteoporosis.