• Toxicological Research
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• 제31권1호
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• pp.11-16
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• 2015

Our body's immune system has defense mechanisms against pathogens such as viruses and bacteria. Immune responses are primarily initiated by the activation of toll-like receptors (TLRs). In particular, TLR4 is well-characterized and is known to be activated by gram-negative bacteria and tissue damage signals. TLR4 requires myeloid differentiation factor 2 (MD2) as a co-receptor to recognize its ligand, lipopolysaccharides (LPS), which is an extracellular membrane component of gram-negative bacteria. Gambogic acid is a xanthonoid isolated from brownish or orange resin extracted from Garcinia hanburyi. Its primary effect is tumor suppression. Since inflammatory responses are related to the development of cancer, we hypothesized that gambogic acid may regulate TLR4 activation. Our results demonstrated that gambogic acid decreased the expression of pro-inflammatory cytokines ($TNF-{\alpha}$, IL-6, IL-12, and $IL-1{\beta}$) in both mRNA and protein levels in bone marrow-derived primary macrophages after stimulation with LPS. Gambogic acid did not inhibit the activation of Interferon regulatory factor 3 (IRF3) induced by TBK1 overexpression in a luciferase reporter gene assay using IFN-${\beta}$-PRD III-I-luc. An in vitro kinase assay using recombinant TBK1 revealed that gambogic acid did not directly inhibit TBK1 kinase activity, and instead suppressed the binding of LPS to MD2, as determined by an in vitro binding assay and confocal microscopy analysis. Together, our results demonstrate that gambogic acid disrupts LPS interaction with the TLR4/MD2 complex, the novel mechanism by which it suppresses TLR4 activation.

• 동의생리병리학회지
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• 제33권4호
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• pp.191-197
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• 2019

This study aims to evaluate the effects of the root bark of Morus alba (RMA) on the regulation of the Hippo-YAP pathway. Hippo-YAP signaling is a critical regulator in controlling organ size and tissue homeostasis. Hippo, the serine/threonine kinase phosphorylate the LATS. Phosphorylated LATS then phosphorylates and inactivates the YAP and TAZ, which are two closely related transcriptional co-activator. Here we report RMA activates the Hippo signaling, thereby inhibits the YAP/TAZ activity. First, we examine the cytotoxic effects of RMA by MTT assay. RMA was cytotoxic at concentrations higher than $50{\mu}g/ml$ in HEK293A cells. The reporter gene assay was performed to measure the activity of TEAD, a key transcription factor that controls cell growth and proliferation. RMA significantly suppressed the luciferase activity. By phos-taq gel shift assay, and western blotting, we showed that RMA enhanced the phosphorylation of YAP in wild type cells, but not in LATS1/2 knock out cells, which means RMA activates classical Hippo pathway. RMA induced the cytoplasmic sequestration of YAP. RMA also suppressed the mRNA expression of CTGF and CYR61; the two major YAP dependent genes. Taken together, RMA is considered to be a good candidate for proliferative disease such as cancer, by facilitating cell death through activating the Hippo signaling pathway.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.64-68
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• 2013

Previous studies have shown that lactic acid bacteria can inhibit inflammatory responses, but the mechanisms are very little known. In this study, transaction and expression of three proinflammatory factors, iNOS, PTGS-2, and IL8, which are closely related to the inflammatory response, were investigated by luciferase reporter assay and RTPCR in HT-29 cells treated by Lactobacillus acidophilus. The results showed that the live L. acidophilus sharply down-regulated the transcription of these three genes. Because there was a NF-${\kappa}B$ binding site located at -265 bp, -225 bp, and -95 bp upstream of the iNOS, PTGS-2, and IL8 promoters, respectively, we further addressed the effects of NF-${\kappa}B$ on transaction of the three promoters by cotransfection. As was expected, NF-${\kappa}Bs$ remarkably upregulated the activity of the reporter gene and, no effect of NF-${\kappa}B$s on IL-8 promoter transaction was found after NF-${\kappa}B$ binding site mutation of the IL8 promoter in HT-29 cells. In conclusion, the live L. acidophilus decreased the transcriptional activity of NF-${\kappa}B$ and, in turn, inhibited the transaction of NF-${\kappa}B$ on the three proinflammatory factors mentioned above.

• Tuberculosis and Respiratory Diseases
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• 제48권5호
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• pp.682-698
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• 2000

Glucocorticoid receptor (GR) functions as a suppressor of inflammation by inhibiting the expression of many cytokine genes activated by NF-${\kappa}B$. The goal of this study is to investigate the mechanism by which GR repress NF-${\kappa}B$ activation in lung epithelial cells. We used A549 and BEAS-2B lung epithelia! cell lines. Using Ig$G{\kappa}$-NF-${\kappa}B$ luciferase reporter gene construct, we found that dexamethasone significantly suppressed TNF-$\alpha$-induced NF-${\kappa}B$ activation and the overexpression of GR showed dose-dependent reduction of TNF-$\alpha$-induced NF-${\kappa}B$ activity in both cell lines. However, DNA binding of NF-${\kappa}B$ induced by TNF-$\alpha$ in electromobility shift assay was not inhibited by dexamethasone. Super shift assay with anti-p65 antibody demonstrated the existence of p65 in NF-${\kappa}B$ complex induced by $\alpha$ Western blot showed that $I{\kappa}B{\alpha}$ degradation induced by TNF-$\alpha$ was not affected by dexamethasone and $I{\kappa}B{\kappa}$ was not induced by dexamethasone, neither. To evaluate p65 specific transactivation, we adopted co-transfection study of Gal4-p65TA1 or TA2 fusion protein expression system together with 5xGal4-luciferase vector. Co-transfection of GR with Gal4-p65TA1 or TA2 repressed luciferase activity profoundly to the level of 10-20% of p65TA1- or TA2-induced transcriptional activity. And this transrepressional effect was abolished by co-transfection of CBP of SRC-1 expression vectors. These results suggest that GR-mediated transrepression of NF-${\kappa}B$ in lung epithelial cells is through competing for binding to limiting amounts of transcriptional coactivators, CBP or SRC-1.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권2호
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• pp.169-174
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• 2004

Bombyx mori nucleopolyhedrovirus(BmNPV) ecdysteroid UDP-glucosyltransferase gene (egt) promoter fragments of different lengths were amplified from BmNPV ZJ-8 genomic DNA by PCR. Reporter plasmids pBmegt542-luc, pBmegt309-luc and pBmegtl59-luc with luciferase (lue) driven by egt promoters were constructed. Both in vitro and in vivo expressions showed that BmNPV egt promoter activity requires the transactivation of viral factor(s), and expression of luc was detected earliest at 24 hrs post infection (pi). BmNPV ZJ-8 homologous region 3 (hr3) increased the expression of luc by over 1,600-fold. Molting hormone of 1.0 - 2.0 $\mu\textrm{g}$/$m\ell$ can dramatically down regulate expression of luc. Juvenile hormone analogue of 0.5-2.0 ${\mu}g$/$m\ell$ increased expression of luc by 145.8% to 75.7%. Deletion assay revealed that the promoter fragment of 159 bp contains the basal promoter structure; Promoter fragments of 309 bp and 542 bp showed similar but much higher transcriptional activities than that of 159 bp, suggesting that nucleotide from -159 to -309 nt upstream the translation initiation site harbors the main cis-acting elements.

• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1331-1342
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• 2021

In this study, we evaluated the mechanism of long non-coding RNA MIR22 host gene (LncRNA MIR22HG) in osteosarcoma cells. Forty-eight paired osteosarcoma and adjacent tissues samples were collected and the bioinformatic analyses were performed. Target genes and potential binding sites of MIR22HG, microRNA (miR)-629-5p and tet methylcytosine dioxygenase 3 (TET3) were predicted by Starbase and TargetScan V7.2 and confirmed by dual-luciferase reporter assay. Cell Counting Kit-8, colony formation and flow cytometry assays were utilized to determine the viability, proliferation and apoptosis of transfected osteosarcoma cells. Pearson's analysis was introduced for the correlation analysis between MIR22HG and miR-629-5p in osteosarcoma tissue. Relative expressions of MIR22HG, miR-629-5p and TET3 were measured by quantitative real-time polymerase chain reaction or Western blot. MiR-629-5p could competitively bind with and was negatively correlated with MIR22HG, the latter of which was evidenced by the high expression of miR-629-5p and low expression of MIR22HG in osteosarcoma tissues. Overexpressed MIR22HG repressed the viability and proliferation but enhanced apoptosis of osteosarcoma cells, which was reversed by miR-629-5p upregulation. TET3 was the target gene of miR-629-5p, and the promotive effects of upregulated miR-629-5p on the viability and proliferation as well as its repressive effect on apoptosis were abrogated via overexpressed TET3. To sum up, overexpressed MIR22HG inhibits the viability and proliferation of osteosarcoma cells, which was achieved via regulation of the miR-629-5p/TET3 axis.

• Tuberculosis and Respiratory Diseases
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• 제51권4호
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• pp.315-324
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• 2001

연구배경 : IL-8은 강력한 화학주성인자로서 결핵감염 부위로 염증세포들을 동원함으로서 결핵균에 대한 숙주의 방어기전에 있어서 중요한 역할을 한다. IL-8의 유전자의 발현에 있어서 NF-${\kappa}B$가 중요한 역할을 한다. 저자들은 결핵 감염시 폐상피세포가 NF-${\kappa}B$ 의존성으로 IL-8을 분비하는지 알아보고자 하였다. 방 법 : 말초혈액단핵구에 결핵균을 감염시키고 24시간 배양 후 배양상층액(CoMTB)을 얻었다. 결핵균, CoMTB로 자극한 A549 세포주의 IL-8 분비 정도를 ELISA 방법으로 측정하였다. CoMTB로 자극한 A549 세포주의 IL-8 mRNA 의 발현 정도를 RT-PCR로, $I{\kappa}B{\alpha}$의 분해를 western blot 분석으로, NF-${\kappa}B$의 핵이동과 DNA 결합은 electrophoretic mobility shift assay(EMSA)를 이용하여, 그리고 NF-${\kappa}B$ 의존성 IL-8 유전자의 전사활성은 luciferase reporter gene assay를 이용하여 측정하였다. 결 과 : A549 세포주를 CoMTB로 24시간 자극하여 얻은 배양액의 IL-8 농도는 $46.8{\pm}4.8\;ng/ml$로 분비하여 결핵균으로 직접 자극하였을 때의 $6.8{\pm}2.9\;ng/ml$보다 높았다. CoMTB로 A549 세포주를 자극하였을 때 IL-8 mRNA의 발현이 증가하였고, $I{\kappa}B{\alpha}$의 분해가 일어났으며, NF-${\kappa}B$의 핵이동과 DNA 결합이 일어났으며, NF-${\kappa}B$ 의존성 IL-8 유전자의 전사활성이 증가하였다. 결 론 : 결핵병변에서 폐상피세포는 결핵균을 탐식한 단핵식 세포와의 상호작용에 의해 NF-${\kappa}B$ 의존성으로 IL-8을 분비한다.

• The Korean Journal of Physiology and Pharmacology
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• 제19권5호
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• pp.441-449
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• 2015

Flavonoids are plant pigments that have been demonstrated to exert various pharmacological effects including anti-cancer, anti-diabetic, anti-atherosclerotic, anti-bacterial, and anti-inflammatory activities. However, the molecular mechanisms in terms of exact target proteins of flavonoids are not fully elucidated yet. In this study, we aimed to evaluate the anti-inflammatory mechanism of scutellarein (SCT), a flavonoid isolated from Erigeron breviscapus, Clerodendrum phlomidis and Oroxylum indicum Vent that have been traditionally used to treat various inflammatory diseases in China and Brazil. For this purpose, a nitric oxide (NO) assay, polymerase chain reaction (PCR), nuclear fractionation, immunoblot analysis, a kinase assay, and an overexpression strategy were employed. Scutellarein significantly inhibited NO production in a dose-dependent manner and reduced the mRNA expression levels of inducible NO synthase (iNOS) and tumor necrosis factor (TNF)-${\alpha}$ in lipopolysaccharide (LPS)-activated RAW264.7 cells. In addition, SCT also dampened nuclear factor (NF)-${\kappa}B$-driven expression of a luciferase reporter gene upon transfection of a TIR-domain-containing adapter-inducing interferon-${\beta}$ (TRIF) construct into Human embryonic kidney 293 (HEK 293) cells; similarly, NF-${\kappa}B$ nuclear translocation was inhibited by SCT. Moreover, the phosphorylation levels of various upstream signaling enzymes involved in NF-${\kappa}B$ activation were decreased by SCT treatment in LPS-treated RAW264.7 cells. Finally, SCT strongly inhibited Src kinase activity and also inhibited the autophosphorylation of overexpressed Src. Therefore, our data suggest that SCT can block the inflammatory response by directly inhibiting Src kinase activity linked to NF-${\kappa}B$ activation.

• Biomolecules & Therapeutics
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• 제22권5호
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• pp.390-399
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• 2014

Chalcones (1,3-diaryl-2-propen-1-ones), a flavonoid subfamily, are widely known for their anti-inflammatory properties. Propenone moiety in chalcones is known to play an important role in generating biological responses by chalcones. In the present study, we synthesized chalcone derivatives structurally modified in propenone moiety and examined inhibitory effect on nitric oxide (NO) production and its potential mechanisms. Among the chalcone derivatives used for this study, TI-I-174 (3-(2-Hydroxyphenyl)-1-(thiophen-3-yl)prop-2-en-1-one) most potently inhibited lipopolysaccharide (LPS)-stimulated nitrite production in RAW 264.7 macrophages. TI-I-174 treatment also markedly inhibited inducible nitric oxide synthase (iNOS) expression. However, TI-I-174 did not significantly affect production of IL-6, cyclooxygenase-2 (COX-2) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), implying that TI-I-174 inhibits production of inflammatory mediators in a selective manner. Treatment of macrophages with TI-I-174 significantly inhibited transcriptional activity of activator protein-1 (AP-1) as determined by luciferase reporter gene assay, whereas nuclear factor-${\kappa}B$ (NF-${\kappa}B$) activity was not affected by TI-I-1744. In addition, TI-I-174 significantly inhibited activation of c-Jun-N-Terminal kinase (JNK) without affecting ERK1/2 and p38MAPK, indicating that down-regulation of iNOS gene expression by TI-I-174 is mainly attributed by blockade of JNK/AP-1 activation. We also demonstrated that TI-I-174 treatment led to an increase in heme oxygenase-1 (HO-1) expression both at mRNA and protein level. Transfection of siRNA targeting HO-1 reversed TI-I-174-mediated inhibition of nitrite production. Taken together, these results indicate that TI-I-174 suppresses NO production in LPS-stimulated RAW 264.7 macrophages via induction of HO-1 and blockade of AP-1 activation.

• Journal of Microbiology and Biotechnology
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• 제31권11호
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• pp.1508-1518
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• 2021

Hsa_circ_0001947 is associated with multiple cancers, but its function in non-small cell lung cancer (NSCLC) is ambiguous and needs further research. The targeting relationship among circ_0001947, miR-661, and downstream of tyrosine kinase 7 (DOK7) was predicted by database and further verified by dual-luciferase reporter assay, while their expressions in cancer tissues and cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). After transfection, cell biological behaviors and expressions of miRNAs, miR-661 and DOK7 were determined by cell function experiments and qRT-PCR, respectively. Circ_0001947 was low-expressed in NSCLC tissues and cells. Circ_0001947 knockdown intensified cell viability and proliferation, induced cell cycle arrest at S phase, suppressed apoptosis and evidently enhanced miR-510, miR-587, miR-661 and miR-942 levels, while circ_0001947 overexpression did the opposite. MiR-661 was a target gene of circ_0001947 that participated in the regulation of circ_0001947 on cell biological behaviors. Furthermore, DOK7, the target gene of miR-661, partly participated in the regulation of miR-661 on cell viability. Hsa_circ_0001947 acts as a sponge of miR-661 to repress NSCLC development by elevating the expression of DOK7.