• Journal of information and communication convergence engineering
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• v.1 no.3
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• pp.139-142
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• 2003

In this paper, we consider the factors that affect a conversion loss performance in designing a single balanced diode mixer integrated with IRF(Image Reject Filter), based on the embedded electrical wavelength placed between the IRF and mixer, diode matching and LO drive amplifier. To evaluate the conversion loss performance, we suggest two types of a single balanced mixer using 90 degree branch line coupler, microstrip line and schottky diode. One is only mixer and the other is integrated with IRF and LO drive amplifier. The measured results of a single balance diode mixer integrated IRF show the conversion loss of 8.5 dB and the flatness of 1 dB p-p from 21.2 GHz to 22.6 GHz with 10 dBm LO. The measured input PI dB and IIP3 are 7 dBm and 15 dBm respectively under the nominal LO power level of 10dBm. The LO/RF and LO/IF isolation are 22 dB and 50 dB, respectively.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.310-315
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• 2020

Orostachys japonicus (O. japonicus) is known as a medicinal plant for the treatment of various symptoms. This study investigated the anti-inflammatory effect of the hexane fraction from O. japonicus (OJH) on the LPS-stimulated response in RAW 264.7 macrophage cells. This study was conducted to confirm the effect of cell cytotoxicity and production of reactive oxygen species (ROS) in OJH-treated macrophage cells. Additionally, pro-inflammatory cytokines and transcription factors were determined using RT-PCR and western blotting assay. OJH showed no change in lactate dehydrogenase (LDH) levels and exhibited reduced ROS levels in LPS-induced inflammatory cells. Moreover, OJH significantly suppressed the mRNA levels of proinflammatory cytokines, including IL-1β, IL-2, IL-6, TNF-α, and IP-10. Furthermore, OJH effectively inhibited the protein levels of AP-1 (p-c-Jun and p-c-Fos) and p-IRF3 in a dose-dependent manner. In conclusion, our results demonstrate that OJH exhibits strong anti-inflammatory activities via regulation of inflammatory factors.

• BMB Reports
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• v.52 no.7
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• pp.469-474
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• 2019

Kruppel-like factor 2 (KLF2) has been implicated in the regulation of cell proliferation, differentiation, and survival in a variety of cells. Recently, it has been reported that KLF2 regulates the p65-mediated transactivation of $NF-{\kappa}B$. Although the $NF-{\kappa}B$ pathway plays an important role in the differentiation of osteoclasts and osteoblasts, the role of KLF2 in these bone cells has not yet been fully elucidated. In this study, we demonstrated that KLF2 regulates osteoclast and osteoblast differentiation. The overexpression of KLF2 in osteoclast precursor cells inhibited osteoclast differentiation by downregulating c-Fos, NFATc1, and TRAP expression, while KLF2 overexpression in osteoblasts enhanced osteoblast differentiation and function by upregulating Runx2, ALP, and BSP expression. Conversely, the downregulation of KLF2 with KLF2-specific siRNA increased osteoclast differentiation and inhibited osteoblast differentiation. Moreover, the overexpression of interferon regulatory protein 2-binding protein 2 (IRF2BP2), a regulator of KLF2, suppressed osteoclast differentiation and enhanced osteoblast differentiation and function. These effects were reversed by downregulating KLF2. Collectively, our data provide new insights and evidence to suggest that the IRF2BP2/KLF2 axis mediates osteoclast and osteoblast differentiation, thereby affecting bone homeostasis.

• Journal of Animal Science and Technology
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• v.62 no.3
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• pp.385-395
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• 2020

Polyinosinic:polycytidylic acid (poly[I:C]) can stimulate Toll-like receptor 3 (TLR3) signaling pathways. In this study, DF-1 cells were treated with poly(I:C) at various concentrations and time points to examine the comparative expression patterns of innate immune response genes. The viability of DF-1 cells decreased from 77.41% to 38.68% when cells were treated different dose of poly(I:C) from 0.1 ㎍/mL to 100 ㎍/mL for 24 h respectively. The expressions of TLR3, TLR4, TLR7, TLR15, TLR21, IL1B, and IL10 were increased in dose- and time-dependent manners by poly(I:C) treatment. On the contrary, the expression patterns of interferon regulatory factors 7 (IRF7), Jun proto-oncogene, AP-1 transcription factor subunit (JUN), Nuclear Factor Kappa B Subunit 1 (NF-κB1), and IL8L2 were varied; IRF7 and IL8L2 were increasingly expressed whereas the expressions of JUN and NF-κB1 were decreased in a dose-dependent manner after they were early induced. In time-dependent analysis, IRF7 expression was significantly upregulated from 3 h to 24 h, whereas JUN and NF-κB1 expressions settled down from 6 h to 24 h after poly(I:C) treatment although they were induced at early time from 1 h to 3 h. Poly(I:C) treatment rapidly increased the expression of IL8L2 from 3 h to 6 h with a plateau at 6 h and then the expression of IL8L2 was dramatically decreased until 24 h after poly(I:C) treatment although the expression level was still higher than the non-treated control. These results may provide the basis for understanding host response to viral infection and its mimicry system in chickens.

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.32-32
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• 1999

No Abstract, See Full Text

• Natural Product Sciences
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• v.28 no.3
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• pp.121-129
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• 2022

Despite considerable efforts, cancer remains an aggressive killer worldwide. Chemotherapeutic drugs that are currently in use lead to destructive side effects and have not succeeded in fulfilling expectations. For centuries, medicinal plants are used for treating various diseases and are also known to have anticancer activity. The main aim of this research was to evaluate antiproliferative activity of saffron, clove, fenugreek, and green tea on Vero and MDA-MB-231 cell lines and to subsequently analyze the effect of these extracts on IRAK-4, TAK1, IKK-alpha, IKK-beta, NF-Kappa B, IRF3, IRF7 genes in Toll Like Receptors (TLRs) pathway. Antiproliferative assay was done by Neutral Red Dye uptake assay. Methanolic extract of green tea was found to be most effective against both cell lines as IC₅₀ was achieved at least concentration of the extract. For molecular studies, MDAMB-231 cells were sensitized with methanolic extract of green tea at same IC₅₀, and RT-PCR was performed to determine the relative expression of genes. Expression of IRAK-4, TAK1, IKK-beta, NF-Kappa B, IRF3 genes was down regulated and IRF7 and IKKalpha was upregulated. Green tea has a potential cytotoxic effect on both cell lines which was demonstrated by its effect on the expression of (TLRs) pathway genes.

• Parasites, Hosts and Diseases
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• v.62 no.1
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• pp.30-41
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• 2024

The dense granule protein of Toxoplasma gondii, inhibitor of signal transducer and activator of transcription 1 (IST) is an inhibitor of signal transducer and activator of transcription 1 (STAT1) transcriptional activity that binds to STAT1 and regulates the expression of inflammatory molecules in host cells. A sterile inflammatory liver injury in pathological acute liver failures occurs when excessive innate immune function, such as the massive release of IFN-γ and TNF-α, is activated without infection. In relation to inflammatory liver injury, we hypothesized that Toxoplasma gondii inhibitor of STAT1 transcription (TgIST) can inhibit the inflammatory response induced by activating the STAT1/IRF-1 mechanism in liver inflammation. This study used IFN-γ and TNF-α as inflammatory inducers at the cellular level of murine hepatocytes (Hepa-1c1c7) to determine whether TgIST inhibits the STAT1/IRF-1 axis. In stable cells transfected with TgIST, STAT1 expression decreased with a decrease in interferon regulatory factor (IRF)-1 levels. Furthermore, STAT1 inhibition of TgIST resulted in lower levels of NF-κB and COX2, as well as significantly lower levels of class II transactivator (CIITA), iNOS, and chemokines (CLXCL9/10/11). TgIST also significantly reduced the expression of hepatocyte proapoptotic markers (Caspase3/8/9, P53, and BAX), which are linked to sterile inflammatory liver injury. TgIST also reduced the expression of adhesion (ICAM-1 and VCAM-1) and infiltration markers of programmed death-ligand 1 (PD-L1) induced by hepatocyte and tissue damage. TgIST restored the cell apoptosis induced by IFN-γ/TNF-α stimulation. These results suggest that TgIST can inhibit STAT1-mediated inflammatory and apoptotic responses in hepatocytes stimulated with proinflammatory cytokines.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.5
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• pp.986-992
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• 2009

Type I interferons (IFNs) are critical mediators of the innate immune system to defend viral infection. Interferon regulatory factor (IRF) and signal transducer and activator of transcription (STAT) play critical roles in type I IFN production in response to viral infection. Luteolin is natural polyphenolic compounds that have anti-inflammatory, cytoprotective and anti-carcinogenic effects. However, the mechanism of action and impact of luteolin on innate immunity is still unknown. In this study, we examined the effects of luteolin on the lipopolysacchride (LPS)-induced inflammatory responses. Luteolin inhibited Type I IFNs expression of mRNA and increased interleukin(IL)-10 expression of mRNA. Next, we examined the protective effects of IL-10 using IL-10 neutralizing antibody (IL-10NA). Blockade of IL-10 action didn't cause a significant reduction of Type I IFNs than LPS-induced luteolin pretreatment. Pretreatment of luteolin inhibited the level of IRF-1, and IRF-7 mRNA and the nuclear translocation of IRF-3. Also, luteolin reduced the activation of STAT - 1, 3. Theses results suggest that luteolin inhibits LPS-induced the production of Type I IFNS by both IRFs and STATs not IL-10 and may be a beneficial drug for the treatment of inflammatory disease.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.435-438
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• 2002

A design of Ku-band(11.7~12.20Hz) monolithic microwave integrated circuit(MMIC) low noise block(LNB) downconverter using self oscillating mixer (SOM) for direct broadcast satellite(DBS) application is presented The proposed LNB downconverter is composed of low noise amplifier(LNA), image reject filter(IRF), SOM , low pass filter(LPF). The conversion gain is 30dB , VSn is less than 1.7: 1 and overall noise figure is less than 1.2dB.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.187-192
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• 2009

Toll-like receptors (TLRs) play an important role in host defense by sensing invading microbial pathogens. The stimulation of TLRs by microbial components triggers the activation of the myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter inducing interferon-$\beta$ (TRIF)-dependent downstream signaling pathways. TLR/MyD88 signaling pathway induces the activation of nuclear factor-kappa B (NF-${\kappa}B$) and the expression of inflammatory cytokine genes, including tumor necrosis factor-alpha, interleukin (IL)-6, IL-12, and IL-$1{\beta}$. On the other hand, TLR/TRIF signaling pathway induces the delayed-activation of NF-${\kappa}B$ and interferon regulatory factor 3 (IRF3), and the expression of type I interferons (IFNs) and IFN-inducible genes. The divalent heavy metal cadmium (Cd) is clearly toxic to most mammalian organ systems, especially the immune system. Yet, the underlying toxic mechanism(s) remain unclear. Cd inhibits the MyD88-dependent pathway by ceasing the activity of inhibitor-${\kappa}B$ kinase. However, it is not known whether Cd inhibits the TRIF-dependent pathway. Presently, Cd inhibited NF-${\kappa}B$ and IRF3 activation induced by lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid. Cd inhibited LPS-induced IRF3 phosphorylation and IFN-inducible genes such as interferon inducible protein-10 and regulated on activation normal T-cell expressed and secreted (RANTES). These results suggest that Cd can modulate TRIF-dependent signaling pathways of TLRs.