• Molecules and Cells
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• 제40권4호
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• pp.299-306
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• 2017

The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level. In this study, we determine the crystal structure of the AphB RD from V. vulnificus under aerobic conditions without modification at the conserved cysteine residue of the RD, even in the presence of the oxidizing agent cumene hydroperoxide. A cysteine to serine amino acid residue mutant RD protein further confirmed that the cysteine residue is not involved in sensing oxidative stress in vitro. Interestingly, an unidentified small molecule was observed in the inter-subdomain cavity in the RD when the crystal was incubated with cumene hydroperoxide molecules, suggesting a new ligand-binding site. In addition, we confirmed the role of AphB in acid tolerance by observing an aphB-dependent increase in cadC transcript level when V. vulnificus was exposed to acidic pH. Our study contributes to the understanding of the AphB molecular mechanism in the process of recognizing the host environment.

• 생명과학회지
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• 제20권2호
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• pp.275-280
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• 2010

Sulforaphane은 십자가화 채소에 존재하는 화합물로 항염증, 항암 및 신생혈관 생성의 억제 효과가 알려짐으로써 최근 많은 연구가 활발히 이루어지고 있으나, LPS에 의한 MMP-9 활성 조절에 대한 연구는 매우 미흡한 편이다. 따라서 본 연구에서 sulforaphane이 LPS 유도에 의한 MMP-9 활성에 미치는 영향에 대해서 조사해 보았다. Raw 264.7 세포에 sulforaphane을 전처리 한 후 LPS를 처리하여 gelatin zymography를 실시해 본 결과, LPS에 의해 유도된 MMP-9 활성 증가가 sulforaphane 농도 의존적으로 감소됨을 확인 하였다. 또한 RT-PCR과 MMP-9의 luciferase assay를 통한 실험에서 sulforaphane의 MMP-9 억제효과가 전사단계에서 조절됨을 추측 할 수 있었다. MMP-9 promoter 부위에 여러 가지의 전사조절인자 결합부위가 존재한다. 특히 AP-1과 NF-${\kappa}B$가 중요 전사조절인자로 작용하여 MMP-9 발현조절에 관여한다. 본 실험에서 sulforaphane에 의한 MMP-9 억제효과 기전에 이들 전사조절인자들의 중요한 역할을 조사하였다. AP-1과 NF-${\kappa}B$ 결합부위를 변형 시킨 vector를 transfection하여 MMP-9의 promoter 활성을 측정한 결과, 정상 vector에 비해 그 활성도가 현저히 떨어짐을 확인하였고, LPS에 의해 증가되는 AP-1과 NF-${\kappa}B$의 basal promoter 활성 또한 sulforaphane에 의해 감소됨을 관찰 할 수 있었다. 이상의 결과에서 sulforaphane의 MMP-9 활성억제효과는 AP-1과 NF-${\kappa}B$와 같은 전사인자들이 MMP-9의 전사를 조절함으로써 일어나는 것임을 알 수 있었다. 그리고 sulforaphane은 세포의 invasion능력 또한 효과적으로 억제시킴을 관찰 할 수 있었는데 이는 MMP-9 활성억제효과와 밀접한 관련이 있음을 추측 할 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제5권5호
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• pp.397-405
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• 2001

The ryanodine receptor, a $Ca^{2+}$ release channel of the sarcoplasmic reticulum (SR), is responsible for the rapid release of $Ca^{2+}$ that activates cardiac muscle contraction. In the excitation-contraction coupling cascade, activation of SR $Ca^{2+}$ release channel is initiated by the activity of sarcolemmal $Ca^{2+}$ channels, the dihydropyridine receptors. Previous study showed that the relaxation defect of diabetic heart was due to the changes of the expressional levels of SR $Ca^{2+}$ATPase and phospholamban. In the diabetic heart contractile abnormalities were also observed, and one of the mechanisms for these changes could include alterations in the expression and/or activity levels of various $Ca^{2+}$ regulatory proteins involving cardiac contraction. In the present study, underlying mechanisms for the functional derangement of the diabetic cardiomyopathy were investigated with respect to ryanodine receptor, and dihydropyridine receptor at the transcriptional and translational levels. Quantitative changes of ryanodine receptors and the dihydropyridine receptors, and the functional consequences of those changes in diabetic heart were investigated. The levels of protein and mRNA of the ryanodine receptor in diabetic rats were comparable to these of the control. However, the binding capacity of ryanodine was significantly decreased in diabetic rat hearts. Furthermore, the reduction in the binding capacity of ryanodine receptor was completely restored by insulin. This result suggests that there were no transcriptional and translational changes but functional changes, such as conformational changes of the $Ca^{2+}$ release channel, which might be regulated by insulin. The protein level of the dihydropyridine receptor and the binding capacity of nitrendipine in the sarcolemmal membranes of diabetic rats were not different as compared to these of the control. In conclusion, in diabetic hearts, $Ca^{2+}$ release processes are impaired, which are likely to lead to functional derangement of contraction of heart. This dysregulation of intracellular $Ca^{2+}$ concentration could explain for clinical findings of diabetic cardiomyopathy and provide the scientific basis for more effective treatments of diabetic patients. In view of these results, insulin may be involved in the control of intracellular $Ca^{2+}$ in the cardiomyocyte via unknown mechanism, which needs further study.

• 생명과학회지
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• 제20권6호
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• pp.853-860
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• 2010

DevSR two-component system은 Mycobacterium smegmatis의 redox sensing에 관련된 주요한 regulatory system이다. DevSR system은 DevS histidine kinase와 DevR response regulator로 구성되어 있다. 저산소 조건에서 DevS histidine kinase는 활성화되어 DevR response regulator를 인산화 시키고, 인산화된 DevR response regulator는 DevR regulon의 transcriptional activator로 작용한다. DevS의 kinase activity는 DevS의 N-terminal에 위치한 GAF domain에 존재하는 heme의 ligand-binding state에 의해 결정된다. 본 연구에서는 C-terminal kinase domain의 redox-responsive cysteine (C547)이 DevS kinase activity의 redox-dependent control과 연관이 있음을 밝혔다. 산소가 존재할 때, C547 residue 사이의 disulfide bond의 형성은 DevS kinase activity를 불활성화 시킨다. $\beta$-mercaptoethanol과 dithiothreitol과 같은 환원제를 이용하여 산화된 DevS를 환원시켰을 때, DevS kinase activity가 복원된 것이 관찰되었다. 또한, C547을 alanine으로 치환했을 때, M. smegmatis의 DevS의 sensory 기능을 부분적으로 손상되는 것이 complementation 실험을 통해 in vivo 상에서 증명되었다.

• 한국양식학회지
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• 제19권3호
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• pp.157-165
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• 2006

우리나라 주요 담수 어종인 미꾸라지를 ecotoxicogenomic 연구 모델 어류로 개발하기 위한 연구의 일환으로 본 어종이 고온 스트레스 자극에 노출되었을때 야기되는 산화성 스트레스를 검출하고자 항산화 효소(antioxidant enzyme; AOE) 유전자의 발현 양상을 분석하였다. 주요 항산화 효소인 superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) 및 glutathione peroxidases (GPXs)의 transcript들을 특이적으로 정량화할 수 있는 semi-quantitative RT-PCR, real-time PCR 또는 northern blot분석을 통해 $23^{\circ}C$에서 $32^{\circ}C$까지 설정된 실험어의 간 조직내 AOE유전자들의 mRNA level을 분석하였다. 고온에 노출되었을 때 본 어종의 AOE들은 일반적으로 증가된 유전자 발현 양상을 나타내었고, 특히 SOD (2배)와 plasma GPX (3배) 유전자가 가장 유의적인 mRNA 증가를 나타내었다. GST의 경우 상대적으로 적은 증가량을 나타내었고 CAT의 경우 고온자극에 반응하지 않았다. 본 어종은 $29^{\circ}C$ 이상에서 AOE 유전자의 발현 증가를 나타내었고 $32^{\circ}C$에 노출되었을 때 1일째부터 SOD와 plasma GPX mRNA의 증가가 관찰되었다.

• Archives of Pharmacal Research
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• 제29권7호
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• pp.591-597
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• 2006

Aerial parts of Artemisia asiatica (Compositae) have been traditionally used as an oriental medicine for the treatment of inflammatory and ulcerogenic diseases. In the present study, artemisolide was isolated as a nuclear factor $(NF)-{\kappa}B$ inhibitor from A. asiatica by activity-guided fractionation. Artemisolide inhibited $NF-{\kappa}B$ transcriptional activity in lipopolysaccharide (LPS)-stimulated macrophages RAW 264.7 with an $IC_{50}$ value of $5.8\;{\mu}M$. The compound was also effective in blocking $NF-{\kappa}B$ transcriptional activities elicited by the expression vector encoding the $NF-{\kappa}B$ p65 or p50 subunits bypassing the inhibitory kB degradation signaling $NF-{\kappa}B$ activation. The macrophages markedly increased their $PGE_2$ and NO production upon exposure to LPS alone. Artemisolide inhibited LPS-induced $PGE_2$ and NO production with $IC_{50}$ values of $8.7\;{\mu}M$ and $6.4\;{\mu}M$, respectively, but also suppressed LPS-induced synthesis of cyclooxygenase (COX)-2 or inducible NO synthase (iNOS). Taken together, artemisolide is a $NF-{\kappa}B$ inhibitor that attenuates LPS-induced production of $PGE_2$ or NO via down-regulation of COX-2 or iNOS expression in macrophages RAW 264.7. Therefore, artemisolide could represent and provide the anti-inflammatory principle associated with the traditional medicine, A. asiatica.

• Animal Bioscience
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• 제37권6호
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• pp.1021-1030
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• 2024

Objective: R-loops are DNA:RNA triplex hybrids, and their metabolism is tightly regulated by transcriptional regulation, DNA damage response, and chromatin structure dynamics. R-loop homeostasis is dynamically regulated and closely associated with gene transcription in mouse zygotes. However, the factors responsible for regulating these dynamic changes in the R-loops of fertilized mouse eggs have not yet been investigated. This study examined the functions of candidate factors that interact with R-loops during zygotic gene activation. Methods: In this study, we used publicly available next-generation sequencing datasets, including low-input ribosome profiling analysis and polymerase II chromatin immunoprecipitation-sequencing (ChIP-seq), to identify potential regulators of R-loop dynamics in zygotes. These datasets were downloaded, reanalyzed, and compared with mass spectrometry data to identify candidate factors involved in regulating R-loop dynamics. To validate the functions of these candidate factors, we treated mouse zygotes with chemical inhibitors using in vitro fertilization. Immunofluorescence with an anti-R-loop antibody was then performed to quantify changes in R-loop metabolism. Results: We identified DEAD-box-5 (DDX5) and histone deacetylase-2 (HDAC2) as candidates that potentially regulate R-loop metabolism in oocytes, zygotes and two-cell embryos based on change of their gene translation. Our analysis revealed that the DDX5 inhibition of activity led to decreased R-loop accumulation in pronuclei, indicating its involvement in regulating R-loop dynamics. However, the inhibition of histone deacetylase-2 activity did not significantly affect R-loop levels in pronuclei. Conclusion: These findings suggest that dynamic changes in R-loops during mouse zygote development are likely regulated by RNA helicases, particularly DDX5, in conjunction with transcriptional processes. Our study provides compelling evidence for the involvement of these factors in regulating R-loop dynamics during early embryonic development.

• 동의생리병리학회지
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• 제28권5호
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• pp.494-498
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• 2014

It is well known that Desomodii Herba (DH) has an effect to eliminate dampness, relieve jaundice and to clear away toxic material, relieve swelling in Korean Medicine. However, the effect of DH on breast cancer invasion is unknown. In this study, we investigated the inhibitory effect of DH extracts (DHE) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced matrix metalloproteinase-9 (MMP-9) expression and cell invasion, as well as the molecular mechanisms involved in MCF-7, human breast cancer cells. DHE inhibits TPA-induced MMP-9 protein and mRNA expressions in a dose-dependent fashion. DHE also inhibited the TPA-induced transcriptional activation of nuclear factor-kappa B (NF-${\kappa}B$). These results indicate that DHE-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of NF-${\kappa}B$ pathway in MCF-7 cells.

• Preventive Nutrition and Food Science
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• 제21권1호
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• pp.62-67
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• 2016

Green tea (Camellia sinensis) is one of the most popular beverages in the world and has been acknowledged for centuries as having significant health benefits. (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant catechin in green tea, and it has been reported to have health benefit effects. Peroxisome proliferator-activated receptor ${\gamma}$ coactivator $(PGC)-1{\alpha}$ is a crucial regulator of mitochondrial biogenesis and hepatic gluconeogenesis. The objective of this study was to investigate whether EGCG from green tea can affect the ability of transcriptional regulation on $PGC-1{\alpha}$ mRNA expression in HepG2 cells and 3T3-L1 adipocytes. To study the molecular mechanism that allows EGCG to control $PGC-1{\alpha}$ expression, the promoter activity levels of $PGC-1{\alpha}$ were examined. The $PGC-1{\alpha}$ mRNA level was measured using quantitative real-time PCR. The -970/+412 bp of $PGC-1{\alpha}$ promoter was subcloned into the pGL3-Basic vector that includes luciferase as a reporter gene. EGCG was found to up-regulate the $PGC-1{\alpha}$ mRNA levels significantly with $10{\mu}mol/L$ of EGCG in HepG2 cells and differentiated 3T3-L1 adipocytes. $PGC-1{\alpha}$ promoter activity was also increased by treatment with $10{\mu}mol/L$ of EGCG in both cells. These results suggest that EGCG may induce $PGC-1{\alpha}$ gene expression, potentially through promoter activation.

• Biomolecules & Therapeutics
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• 제23권1호
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• pp.39-44
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• 2015

Tolfenamic acid (TA) is a traditional non-steroid anti-inflammatory drug (NSAID) and has been broadly used for the treatment of migraines. Nuclear factor kappa B (NF-${\kappa}B$) is a sequence-specific transcription factor and plays a key role in the development and progression of inflammation and cancer. We performed the current study to investigate the underlying mechanisms by which TA suppresses inflammation focusing on NF-${\kappa}B$ pathway in TNF-${\alpha}$ stimulated human normal and cancer cell lines and lipopolysaccharide (LPS)-stimulated mouse macrophages. Different types of human cells (HCT116, HT-29 and HEK293) and mouse macrophages (RAW264.7) were pre-treated with different concentrations of TA and then exposed to inflammatory stimuli such as TNF-${\alpha}$ and LPS. Transcriptional activity of NF-${\kappa}B$, $l{\kappa}B-{\alpha}$-degradation, p65 translocation and mitogen-activated protein kinase (MAPK) activations were measured using luciferase assay and Western blots. Pre-treatment of TA repressed TNF-${\alpha}$- or LPS-stimulated NF-${\kappa}B$ transactivation in a dose-dependent manner. TA treatment reduced degradation of $l{\kappa}B-{\alpha}$ and subsequent translocation of p65 into nucleus. TA significantly down-regulated the phosphorylation of c-Jun N-terminal kinase (JNK). However, TA had no effect on NF-${\kappa}B$ signaling and JNK phosphorylation in HT-29 human colorectal cancer cells. TA possesses anti-inflammatory activities through suppression of JNK/NF-${\kappa}B$ pathway in different types of cells.