• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1651-1658
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• 2020

Since Zika virus (ZIKV) was first detected in Uganda in 1947, serious outbreaks have occurred globally in Yap Island, French Polynesia and Brazil. Even though the number of infections and spread of ZIKV have risen sharply, the pathogenesis and replication mechanisms of ZIKV have not been well studied. ZIKV, a recently highlighted Flavivirus, is a mosquito-borne emerging virus causing microcephaly and the Guillain-Barre syndrome in fetuses and adults, respectively. ZIKV polyprotein consists of three structural proteins named C, prM and E and seven nonstructural proteins named NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5 in an 11-kb single-stranded positive sense RNA genome. The function of individual ZIKV genes on the host innate immune response has barely been studied. In this study, we investigated the modulations of the NF-κB promoter activity induced by the MDA5/RIG-I signaling pathway. According to our results, two nonstructural proteins, NS2A and NS4A, dramatically suppressed the NF-κB promoter activity by inhibiting signaling factors involved in the MDA5/RIG-I signaling pathway. Interestingly, NS2A suppressed all components of MDA5/RIG-I signaling pathway, but NS4A inhibited most signaling molecules, except IKKε and IRF3-5D. In addition, both NS2A and NS4A downregulated MDA5-induced NF-κB promoter activity in a dosedependent manner. Taken together, our results suggest that NS2A and NS4A signifcantly antagonize MDA5/RIG-I-mediated NF-κB production, and these proteins seem to be controlled by different mechanisms. This study could help understand the mechanisms of how ZIKV controls innate immune responses and may also assist in the development of ZIKV-specific therapeutics.

• Journal of Ginseng Research
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• 제35권2호
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• pp.200-208
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• 2011

Ginsenoside (G) $Rp_1$ is a ginseng saponin derivative with anti-cancer and anti-inflammatory activities. In this study, we examined the mechanism by which G-$Rp_1$ inhibits inflammatory responses of cells. We did this using a strategy in which DNA constructs containing cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) promoters were transfected into HEK293 cells. G-$Rp_1$ strongly inhibited the promoter activities of COX-2 and iNOS; it also inhibited lipopolysaccharide induced upregulation of COX-2 and iNOS mRNA levels in RAW264.7 cells. In HEK293 cells G-$Rp_1$ did not suppress TANK binding kinase 1-, Toll-interleukin-1 receptor-domain-containing adapter-inducing interferon-${\beta}$ (TRIF)-, TRIF-related adaptor molecule (TRAM)-, or activation of interferon regulatory factor (IRF)-3 and nuclear factor (NF)-${\kappa}$B by the myeloid differentiation primary response gene (MyD88)-induced. However, G-$Rp_1$ strongly suppressed NF-${\kappa}$B activation induced by I${\kappa}$B kinase (IKK)${\beta}$ in HEK293 cells. Consistent with these results, G-$Rp_1$ substantially inhibited IKK${\beta}$-induced phosphorylation of $I{\kappa}B{\alpha}$ and p65. These results suggest that G-$Rp_1$ is a novel anti-inflammatory ginsenoside analog that can be used to treat IKK${\beta}$/NF-${\kappa}$B-mediated inflammatory diseases.

• 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.

• 미생물학회지
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• 제42권4호
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• pp.319-325
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• 2006

칡을 첨가하여 배양한 아가리쿠스버섯(Agaricus blaxei Murill)으로 부터 열수추출, gel filtration chromatography, DEAE ion exchange chromatography를 통하여 아가리쿠스 $\beta$-glucan (AG)을 추출하였다. 추출한 아가리쿠스 $\beta$-glucan에 Bacillus megaterium 유래의 endo-$\beta$-(1$\rightarrow$6)-glucanase를 처리하여 올리고당류(AO)를 얻었다. 이렇게 얻은 AG와 AO를 이용하여 HT-29 인체 대장암 세포에 대한 항암 활성을 조사한 결과, 암세포의 성장 억제 효과는 시료의 처리 농도에 의존적으로 증가하였으며, apoptosis assay에서 암세포의 apoptosis 유발이 농도에 의존적으로 증가되었다. 또한, 암세포의 세포 주기를 분석한 결과, apoptosis 발생을 뜻하는 G0 (sub-G1)기와 G1기의 비율이 증가한 반면 S기와 G2/M기는 대조군에 비해 감소되었다. 이러한 결과를 바탕으로 암세포의 apoptosis 증가에 대한 AO의 작용이 어떤 유전자와 연관이 있는지를 알아보기 위하여 cDNA microarray를 통해 유전자의 발현율을 검색한 결과, apoptosis의 내부 외부 경로에 영향을 주는 유전자(TNESE9, TNFRSF9, FADD, CASP8, BAD, CRADD, CASP9 등)의 발현이 증가되었고 세포 분열 주기의 진행과 관련된 유전자(CCND2와 CDK2)의 발현이 감소되었으며, 세포 분열 주기를 지체시키는 유전자 (CDKN2A)의 발현은 증가되었다. 또한, 사이토카인을 암호하는 유전자 (IL6, IL18, IL6R 등)와 tumor suppressor와 관련된 유전자 (CEACAM1, TP53BP2, IRF1및 PHB)의 발현이 2배 이상 증가된 것을 확인할 수 있었다. 따라서 HT-29 인체 대장암세포에 대한 AO의 성장 억제 작용은 G0/Gl기를 지체시켜 암세포 증식을 억제하고 apoptosis에 의해 암세포를 사멸시키는 항암 활성을 나타내는 것으로 확인되었으며, 특허 AO가 AG보다 현저한 활성을 보였다. 더 나아가 아가리쿠스 $\beta$-glucan (AG)과 올리고당류 (AO)는 항암 활성을 가진 대체 의약 소재로 개발될 수 있을 것으로 기대된다.

• Archives of Pharmacal Research
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• 제25권6호
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• pp.946-953
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• 2002

Bisphenol A [2, 2 bis (4-hydoxyphenyl) propane; BPA] is a widely used endocrine disruptors and has estrogenic: activities. Although interests on biological effect of BPA are rising, evidences of its effect on immune system are lacking. We investigated that the effect of BPA on immune parameters to postulate the mechanism, and BPA interruptions between neuroendocrine and immune system. BPA was administrated to mice by p.o. (as a drinking water) dose on 0.015, 1.5 and 30 mg/ml for 4 weeks. The BPA treatment did not result in any change in body weight, spleen weight and distribution of lymphocyte subpopulation collected from spleen. BPA induced prolactin production in spleen, and exposure of SPA increased the activity of splenocyte proliferation in response to Con A (p<0.001). The production of a strong Th-1 type cytokine ($IFN-{\gamma}$) was induced while Th-2 type (IL-4) was suppressed by SPA treatment. These were consistent with RT-PCR results of transcription factor GATA-3 and IRF-1. These findings suggested that stimulation of prolactin production by estrogenic effects of SPA would affect cytokine profiles, and lead to imbalanced cellular immune response. In addition, we could speculate that prolactin and cytokine is important mediator involved in network between neuroendocrine and immune system by BPA.

• Molecules and Cells
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• 제38권6호
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• pp.548-561
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• 2015

By combining conventional single cell analysis with flow cytometry and public database searches with bioinformatics tools, we extended the expression profiling of thymic stromal cotransporter (TSCOT), Slc46A2/Ly110, that was shown to be expressed in bipotent precursor and cortical thymic epithelial cells. Genome scale analysis verified TSCOT expression in thymic tissue- and cell type- specific fashion and is also expressed in some other epithelial tissues including skin and lung. Coexpression profiling with genes, Foxn1 and Hoxa3, revealed the role of TSCOT during the organogenesis. TSCOT expression was detected in all thymic epithelial cells (TECs), but not in the $CD31^+$endothelial cell lineage in fetal thymus. In addition, ABC transporter-dependent side population and Sca-$1^+$ fetal TEC populations both contain TSCOT-expressing cells, indicating TEC stem cells express TSCOT. TSCOT expression was identified as early as in differentiating embryonic stem cells. TSCOT expression is not under the control of Foxn1 since TSCOT is present in the thymic rudiment of nude mice. By searching variations in the expression levels, TSCOT is positively associated with Grhl3 and Irf6. Cytokines such as IL1b, IL22 and IL24 are the potential regulators of the TSCOT expression. Surprisingly, we found TSCOT expression in the lung is diminished in lung cancers, suggesting TSCOT may be involved in the suppression of lung tumor development. Based on these results, a model for TEC differentiation from the stem cells was proposed in context of multiple epithelial organ formation.

• 한국군사과학기술학회지
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• 제21권2호
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• pp.166-172
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• 2018

To develop and evaluate the real-time SAR(Synthetic Aperture Radar) motion measurement system, true antenna phase center(APC) positions during SAT(Synthetic Aperture Time) are needed. In this paper, CDGPS(Carrier phase Differential Global Positioning System) post processing method is proposed to get the true APC position for spotlight SAR image formation. The CDGPS position is smoothed to remove high frequency noise which exists inherently in the carrier phase measurement. This paper shows smoothed CDGPS data is enough to provide the true APC for high-quality SAR image formation through motion measurement result, phase error estimation and IRF(Impulse Response Function) analysis.

• Nutrition Research and Practice
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• 제17권5호
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• pp.827-843
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• 2023

BACKGROUND/OBJECTIVES: Mitochondrial DNA leakage leads to inflammatory responses via endosome activation. This study aims to evaluate whether the perennial grass water extract (Pogonatherum panicum) ameliorate mitochondrial DNA (mtDNA) leakage. MATERIALS/METHODS: The major bioactive constituents of P. paniceum (PPW) were investigated by high-performance liquid chromatography, after which their antioxidant activities were assessed. In addition, RAW 264.7 macrophages were stimulated with lipopolysaccharide, resulting in mitochondrial damage. Quantitative polymerase chain reaction and enzyme-linked immunosorbent assay were used to examine the gene expression and cytokines. RESULTS: Our results showed that PPW extract-treated activated cells significantly decrease reactive oxygen species and nitric oxide levels by reducing the p2^phox and iNOS expression and lowering cytokine-encoding genes, including IL-6, TNF-α, IL-1β, PG-E2 and IFN-γ relative to the lipopolysaccharide (LPS)-activated macrophages. Furthermore, we observed that LPS enhanced the mtDNA leaked into the cytoplasm, increasing the transcription of Tlr9 and signaling both MyD88/Irf7-dependent interferon and MyD88/NF-κb p65-dependent inflammatory cytokine mRNA expression but which was alleviated in the presence of PPW extract. CONCLUSIONS: Our data show that PPW extract has antioxidant and anti-inflammatory activities by facilitating mtDNA leakage and lowering the Tlr9 expression and signaling activation.

• Molecules and Cells
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• 제41권3호
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• pp.214-223
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• 2018

Oligoadenylate synthetase (OAS) protein family is the major interferon (IFN)-stimulated genes responsible for the activation of RNase L pathway upon viral infection. OAS-like (OASL) is also required for inhibition of viral growth in human cells, but the loss of one of its mouse homolog, OASL1, causes a severe defect in termination of type I interferon production. To further investigate the antiviral activity of OASL1, we examined its subcellular localization and regulatory roles in IFN production in the early and late stages of viral infection. We found OASL1, but not OASL2, formed stress granules trapping viral RNAs and promoted efficient RLR signaling in early stages of infection. Stress granule formation was dependent on RNA binding activity of OASL1. But in the late stages of infection, OASL1 interacted with IRF7 transcripts to inhibit translation resulting in down regulation of IFN production. These results implicate that OASL1 plays context dependent functions in the antiviral response for the clearance and resolution of viral infections.

• 조명전기설비학회논문지
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• 제20권2호
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• pp.16-23
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• 2006

본 논문에서는 고역률을 가지고 영전압 스위칭으로 동작되는 새로운 단일 전력단 고주파 공진 인버터 링크형 DC-DC 컨버터 회로에 관하여 기술하고 있다. 제안된 토폴로지는 역률 교정기로써 하프 브리지형 부스트 컨버터와 하프 브리지 고주파 공진 컨버터를 단일 전력단으로 일체화 시켰다. 역률 보상용 부스트 컨버터의 부스트 인덕터 전류를 가변 스위칭 주파수와 일정 듀티비를 가지고 불연속 전류 모드(DCM)로 동작시킴으로써 부가적인 입력 전류제어기 없이 높은 입력 역률을 얻을 수 있다. 또 제안한 토폴로지의 이론해석을 무차원화 파라미터를 도입하여 범용성 있게 하여 회로 설계 전단계에서 필요한 특성값을 도식적으로 표현하다. 첨가해, 제안한 토폴로지의 상용화 가능성과 이론해석의 정당성을 입증하기 위해 스위칭 소자로 Power-MOSFET IRF 740을 제안회로 토폴로지의 스위칭 소자로 채용해 실험 장치를 구성하여 검토를 행하였다. 제안된 컨버터는 향후 통신용 DC/DC 컨버터의 전원장치, 방전등용 진원장치 등의 전원시스템에 유용히 사용될 것으로 사료된다.