• Molecules and Cells
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• 제41권8호
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• pp.753-761
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• 2018

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is identified as a signaling adaptor protein that regulates bone metabolism, immunity, and the development of several tissues. Therefore, its functions are closely associated with multiple diseases. TRAF6 is also involved in the regulation of hematopoiesis under steady-state conditions, but the role of TRAF6 in modulating hematopoietic stem and progenitor cells (HSPCs) during the developmental stages remains unknown. Here, we report that the deletion of TRAF6 in hematopoietic lineage cells resulted in the upregulation of HSPCs in the fetal liver at the prenatal period. However, in the early postnatal period, deletion of TRAF6 drastically diminished HSPCs in the bone marrow (BM), with severe defects in BM development and extramedullary hematopoiesis in the spleen being identified. In the analysis of adult HSPCs in a BM reconstitution setting, TRAF6 played no significant role in HSPC homeostasis, albeit it affected the development of T cells. Taken together, our results suggest that the role of TRAF6 in regulating HSPCs is altered in a spatial and temporal manner during the developmental course of mice.

• The Korean journal of internal medicine
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• 제33권6호
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• pp.1103-1110
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• 2018

Background/Aims: Several epidemiological studies have validated the association of interleukin gene polymorphisms with acute pancreatitis (AP) in different populations. However, there have been few studies in Asian ethnic groups. We aimed to investigate the relationships between inflammatory cytokine polymorphisms and AP as pilot research in a Korean ethnic group. Methods: Patients who had been diagnosed with AP were prospectively enrolled. DNA was extracted from whole blood, and DNA sequencing was subsequently performed. Single-nucleotide polymorphisms (SNPs) of the interleukin $1{\beta}$ (IL1B), interleukin 1 receptor antagonist (IL1RN), and tumor necrosis factor ${\alpha}$ (TNFA) genes of patients with AP were compared to those of normal controls. Results: Between January 2011 and January 2013, a total of 65 subjects were enrolled (40 patients with AP vs. 25 healthy controls). One intronic SNP (IL1RN -1129T>C, rs4251961) was significantly associated with the risk of AP (odds ratio, 0.304; 95% confidence interval, 0.095 to 0.967; p = 0.043). However, in our study, AP was not found to be associated with polymorphisms in the promoter regions of inflammatory cytokine genes, including IL1B (-118C>T, c47+242C>T, +3954C/T, and -598T>C) and TNFA (-1211T>C, -1043C>A, -1037C>T, -488G>A, and -418G>A). Conclusions: IL1RN -1129T>C (rs4251961) genotypes might be associated with a significant increase of AP risk in a Korean ethnic group.

• BMB Reports
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• 제53권8호
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• pp.425-430
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• 2020

Tumor necrosis factor-inducible gene 6 protein (TSG-6) is a cytokine secreted by mesenchymal stem cells (MSCs) and regulates MSC stemness. We previously reported that TSG-6 changes primary human hepatic stellate cells (pHSCs) into stem-like cells by activating yes-associated protein-1 (YAP-1). However, the molecular mechanism behind the reprogramming action of TSG-6 in pHSCs remains unknown. Cluster of differentiation 44 (CD44) is a transmembrane protein that has multiple functions depending on the ligand it is binding, and it is involved in various signaling pathways, including the Wnt/β-catenin pathway. Given that β-catenin influences stemness and acts downstream of CD44, we hypothesized that TSG-6 interacts with the CD44 receptor and stimulates β-catenin to activate YAP-1 during TSG-6-mediated transdifferentiation of HSCs. Immunoprecipitation assays showed the interaction of TSG-6 with CD44, and immunofluorescence staining analyses revealed the colocalization of TSG-6 and CD44 at the plasma membrane of TSG-6-treated pHSCs. In addition, TSG-6 treatment upregulated the inactive form of phosphorylated glycogen synthase kinase (GSK)-3β, which is a negative regulator of β-catenin, and promoted nuclear accumulation of active/nonphosphorylated β-catenin, eventually leading to the activation of YAP-1. However, CD44 suppression in pHSCs following CD44 siRNA treatment blocked the activation of β-catenin and YAP-1, which inhibited the transition of TSG-6-treated HSCs into stem-like cells. Therefore, these findings demonstrate that TSG-6 interacts with CD44 and activates β-catenin and YAP-1 during the conversion of TSG-6-treated pHSCs into stem-like cells, suggesting that this novel pathway is an effective therapeutic target for controlling liver disease.

• Biomolecules & Therapeutics
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• 제24권4호
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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.

• BMB Reports
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• 제52권6호
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• pp.373-378
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• 2019

The nucleotide-binding and oligomerization domain (NOD) is an innate pattern recognition receptor that recognizes pathogen- and damage-associated molecular patterns. The 29-kDa amino-terminal fibronectin fragment (29-kDa FN-f) is a matrix degradation product found in the synovial fluids of patients with osteoarthritis (OA). We investigated whether NOD2 was involved in 29-kDa FN-f-induced pro-catabolic gene expression in human chondrocytes. The expression of mRNA and protein was measured using quantitative real-time polymerase chain reaction (qrt-PCR) and Western blot analysis. Small interfering RNAs were used for knockdown of NOD2 and toll-like receptor 2 (TLR-2). An immunoprecipitation assay was performed to examine protein interactions. The NOD2 levels in human OA cartilage were much higher than in normal cartilage. NOD1 and NOD2 expression, as well as pro-inflammatory cytokines, including interleukin-1beta (IL-$1{\beta}$) and tumor necrosis factor-alpha (TNF-${\alpha}$), were upregulated by 29-kDa FN-f in human chondrocytes. NOD2 silencing showed that NOD2 was involved in the 29-kDa FN-f-induced expression of TLR-2. Expressions of IL-6, IL-8, matrix metalloproteinase (MMP)-1, -3, and -13 were also suppressed by TLR-2 knockdown. Furthermore, NOD2 and TLR-2 knockdown data demonstrated that both NOD2 and TLR-2 modulated the expressions of their adaptors, receptorinteracting protein 2 (RIP2) and myeloid differentiation 88, in 29-kDa FN-f-treated chondrocytes. 29-kDa FN-f enhanced the interaction of NOD2, RIP2 and transforming growth factor beta-activated kinase 1 (TAK1), an indispensable signaling intermediate in the TLR-2 signaling pathway, and activated nuclear factor-${\kappa}B$ (NF-${\kappa}B$), subsequently leading to increased expressions of pro-inflammatory cytokines and cartilage-degrading enzymes. These results demonstrate that 29-kDa FN-f modulated pro-catabolic responses via cross-regulation of NOD2 and TLR-2 signaling pathways.

• Asian-Australasian Journal of Animal Sciences
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• 제29권1호
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• pp.134-141
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• 2016

To investigate the role of polysaccharide from Acanthopanax senticosus (ASPS) in preventing lipopolysaccharide (LPS)-induced intestinal injury, 18 mice (at 5 wk of age) were assigned to three groups with 6 replicates of one mouse each. Mice were administrated by oral gavage with or without ASPS (300 mg/kg body weight) for 14 days and were injected with saline or LPS at 15 days. Intestinal samples were collected at 4 h post-challenge. The results showed that ASPS ameliorated LPS-induced deterioration of digestive ability of LPS-challenged mice, indicated by an increase in intestinal lactase activity (45%, p<0.05), and the intestinal morphology, as proved by improved villus height (20.84%, p<0.05) and villus height:crypt depth ratio (42%, p<0.05), and lower crypt depth in jejunum (15.55%, p<0.05), as well as enhanced intestinal tight junction proteins expression involving occludin-1 (71.43%, p<0.05). ASPS also prevented intestinal inflammation response, supported by decrease in intestinal inflammatory mediators including tumor necrosis factor ${\alpha}$ (22.28%, p<0.05) and heat shock protein (HSP70) (77.42%, p<0.05). In addition, intestinal mucus layers were also improved by ASPS, as indicated by the increase in number of goblet cells (24.89%, p<0.05) and intestinal trefoil peptide (17.75%, p<0.05). Finally, ASPS facilitated mRNA expression of epidermal growth factor (100%, p<0.05) and its receptor (200%, p<0.05) gene. These results indicate that ASPS can prevent intestinal mucosal barrier injury under inflammatory conditions, which may be associated with up-regulating gene mRNA expression of epidermal growth factor and its receptor.

• Journal of Veterinary Science
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• 제24권1호
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• pp.2.1-2.14
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• 2023

Background: Hypothermia is a crucial environmental factor that elevates the risk of cardiovascular disease, but the underlying effect is unclear. Objectives: This study examined the role of cold stress (CS) in cardiac injury and its underlying mechanisms. Methods: In this study, a chronic CS-induced myocardial injury model was used; mice were subjected to chronic CS (4℃) for three hours per day for three weeks. Results: CS could result in myocardial injury by inducing the levels of heat shock proteins 70 (HSP70), enhancing the generation of creatine phosphokinase-isoenzyme (CKMB) and malondialdehyde (MDA), increasing the contents of tumor necrosis factor-α (TNF-α), high mobility group box 1 (HMGB1) interleukin1b (IL-1β), IL-18, IL-6, and triggering the depletion of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). Multiple signaling pathways were activated by cold exposure, including pyroptosis-associated NOD-like receptor 3 (NLRP3)-regulated caspase-1-dependent/Gasdermin D (GSDMD), inflammation-related toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)-mediated nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK), as well as oxidative stressinvolved thioredoxin-1/thioredoxin-interacting protein (Txnip) signaling pathways, which play a pivotal role in myocardial injury resulting from hypothermia. Conclusions: These findings provide new insights into the increased risk of cardiovascular disease at extremely low temperatures.

• Journal of Ginseng Research
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• 제32권4호
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• pp.315-323
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• 2008

In the previous studies, we isolated the compound K rich fractions (CKRF) and showed that CKRF inhibited Toll-like receptor (TLR) 4- or TLR9-induced inflammatory signaling. To extend our previous studies,1) we investigated the molecular mechanisms of CKRF in the TLR4-associated signaling via nuclear factor (NF)-${\kappa}B$, and in vivo role of CKRF for induction of tolerance in lipopolysaccharide (LPS)-induced septic shock. In murine bone marrow-dervied macrophages, CKRF significantly inhibited the induction of mRNA expression of proinflammatory mediators such as tumor necrosis factor-${\alpha}$, interleukin-6, cyclooxygenase-2, and inducible nitric oxide synthase. In addition, CKRF significantly attenuated the transcriptional activities of TLR4/LPS-induced NF-${\kappa}B$. Nuclear translocation of NF-${\kappa}B$ in response to LPS stimulation was significantly abrogated by pre-treatment with CKRF. Furthermore, CKRF inhibited the recruitment of p65 to the interferon-sensitive response element flanking region in response to LPS. Finally, oral administration of CKRF significantly protected mice from Gram-negative bacterial LPS-induced lethal shock and inhibited systemic inflammatory cytokine levels. Together, these results demonstrate that CKRF modulates the TLR4-dependent NF-${\kappa}B$ activation, and suggest a therapeutic role for Gram-negative septic shock.

• 대한의생명과학회지
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• 제25권1호
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• pp.92-98
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• 2019

Metformin is a drug used for the treatment of diabetes and is associated with anti-inflammatory reaction, but the underlying mechanism is unclear. In this study, we investigated the effect of metformin on the inflammatory response in BV-2 microglial cells induced by lipopolysaccharide (LPS) and S100 calcium-binding protein A8 (S100A8). The results revealed that metformin significantly attenuated several inflammatory responses in BV-2 microglial cells, including the secretion of pro-inflammatory cytokines, such as tumor necrosis factor-${\alpha}$ and interleukin (IL)-6, involved in the activation of Beclin-1, a crucial regulator of autophagy. In addition, metformin inhibited the LPS-induced phosphorylation of ERK. Metformin also suppressed the activation of NOD-like receptor pyrin domain containing 3 inflammasomes composed of NLRP3, caspase-1, and apoptosis-associated speck like protein containing a caspase recruitment domain, which are involved in the innate immune response. Notably, metformin decreased the secretion of S100A8-induced IL-6 production. These findings suggest that metformin alleviates the neuroinflammatory response via autophagy activation.

• 한국균학회지
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• 제46권2호
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• pp.161-176
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• 2018

진균류 유래의 ${\beta}$-glucan은 pathogen-associated molecular patterns의 일종이기도 하며 면역촉진과 항암작용을 나타냄이 알려져 있지만 세포 내 신호전달에 관해서는 알려진 바가 많지 않다. 대식세포주인 RAW264.7 세포에 불로초에서 추출한 ${\beta}$-glucan을 처리하였을 때 세포막에서는 덱틴-1, toll-like receptor 2, 4, 6의 발현이 증가되었으며, 세포 내에서는 macrophage inflammatory protein (MIP)-1a, MIP-$1{\beta}$, MIP-$1{\gamma}$, IL-$1{\beta}$ 그리고 tumor necrosis factor (TNF)-${\alpha}$의 발현이 증가되었다. 또한 대식세포주에 불로초의 ${\beta}$-glucan과 PI3K 또는 MEK1/MEK2 억제제를 각각 처리하였을 때에 세포 내의 MIP-1a, MIP-$1{\beta}$, MIP-$1{\gamma}$, interleukin-$1{\beta}$, TNF-${\alpha}$의 발현이 감소되었다. 따라서 불로초의 ${\beta}$-glucan은 대식세포에서 MyD88의 경로인 PI3K/Akt를 경유할 뿐만 아니라 MEK 경로를 활성화시킴으로써 다양한 면역조절작용이 가능한 것으로 여겨진다.