• Animal cells and systems
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• v.16 no.2
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• pp.87-94
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• 2012

Nur77 is a member of the nuclear receptor 4A (NR4A) subgroup, which has been implicated in energy metabolism. Although Nur77 is found in adipose tissue, where TR4 plays a key role in lipid homeostasis, the role of Nur77 in adipogenesis is still controversial. Although the Nur77 responsive element (AAAGGTCA) is partially overlapped with TR4-binding sites (AGGTCA $n$ AGGTCA: $n$=0-6), the regulatory role of Nur77 in TR4 function associated with adipocyte biology remains unclear. Here, we found that Nur77 inhibits adipogenesis and TR4 transcriptional activity. Treatment with a Nur77 agonist, 1,1-bis(3'-indolyl)-1-($p$-anisyl)-methane, during 3T3-L1 adipocyte differentiation reduced adipogenesis. In reporter gene analysis, Nur77 specifically suppressed TR4 transcription activity but had little effect on $PPAR{\gamma}$ transcription activity. Consistently, Nur77 also suppressed TR4-induced promoter activity of the TR4 target gene PEPCK, which is known to be important for glyceroneogenesis in adipose tissue. Furthermore, Nur77 suppressed TR4 binding to TR4 response elements without direct interaction with TR4, suggesting that Nur77 may inhibit TR4 transcription activity via binding competition for TR4-binding sites. Furthermore, DIM-C-$pPhOCH_3$ substantially suppressed TR4-induced PEPCK expression in 3T3-L1 adipocytes. Together, our data demonstrate that Nur77 plays an inhibitory role in TR4-induced PEPCK expression in 3T3-L1 adipocytes.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.107-107
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• 2003

The heavy metal cadmium is a xenobiotic toxicant of environmental and occupational concern and it has been classified as a human carcinogen. Inhalation of cadmium has been implicated in the development of emphysema and pulmonary fibrosis, but, the detailed mechanism by which cadmium induces adverse biological effects is not yet known. Therefore, we undertook the investigation of genes that are induced after cadmium exposure to illustrate the mechanism of cadmium toxicity For this purpose, we employed the polymerase chain reaction-based suppression subtractive hybridization technique. We identified 29 different cadmium-inducible genes in human peripheral mononuclear cells, such as macrophage migration inhibitory factor, lysophosphatidic acid acyltransferase-${\alpha}$, enolase-1${\alpha}$, VEGF, Bax, neuron-derived orphan receptor-1, and Nur77, which are known to be associated with inflammation, cell survival, and apoptosis. Induction of these genes by cadmium treatment was further confirmed by semi-quantitative reverse-transcription polymerase chain reaction. Further, we found that these genes were also induced after cadmium exposure in normal human lung fibroblast cell line, WI-38, suggesting potential use of this induction profile to monitor cadmium toxicity in the lung. Next, Nur77, one of cadmium-inducible genes, was further studied since the products of Nur77 are known to be involved in the apoptotic process of lung cells. Following cadmium treatment, Nur77 gene expression was increased at protein-level in A549 cells. Consistently, the reporter containing Nur77 binding sequence was activated by 2.5-fold after exposure to cadmium in reporter gene analysis by transient transfection experiments. When the plasmid encoding dominant negative Nur77 that represses the transcriptional function of wild-type Nur77 was transfected into A549 cells, the expression of Bax was significantly reduced, suggesting that induction of Nur77 was an important process in cadmium-induced apoptosis in the cells. Cadmium induced the expression of Nur77 in vivo, confirming the relevance of the data obtained in viro. Together our results suggest that Nur77 gene expression in exposure to cadmium leads apoptosis of lung cells which may cause pathological changes in lung.

• Molecules and Cells
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• v.26 no.1
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• pp.74-80
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• 2008

Bisphenol A bis (2,3-dihydroxypropyl) ether ($BADGE.2H_2O$) is a component of commercial liquid epoxy resins commonly used in the food-packing industry and in dental sealants. There is evidence that it has significant estrogenic activity. Nur77 plays a crucial role in the regulation of certain genes involved in LH-mediated steroidogenesis in testicular Leydig cells. It was previously demonstrated that Bisphenol A (BPA) stimulates Nur77 gene induction and steroidogenesis. In this study, we investigated the effects of $BADGE.2H_2O$ on Nur77 gene expression and steroidogenesis. Northern blot analysis showed that it increased the expression of Nur77 mRNA and protein, and transient transfection assays demonstrated that it increased the promoter activity and transactivation of Nur77. It also increased the expression of certain steroidogenic genes, such as StAR and $3{\beta}$-HSD. Finally, over-expression of a dominant negative Nur77 cDNA via adenoviral infection reduced $BADGE.2H_2O$-mediated progesterone biosynthesis. These results indicate that $BADGE.2H_2O$ disrupts testicular steroidogenesis by increasing Nur77 gene expression.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.3
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• pp.109-116
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• 2018

SSDs that are not allowed in-place update within the allocated page cause another allocation of a new page that will replace the previous page at the moment data modification occurs. This intrinsic characteristic of SSDs requires many changes to the existing HDD-based IO theory. In this paper, we conduct a performance comparison of FTL caching strategy in perspective of cache hashing (Global vs. grouped) and caching algorithm (LRU vs. NUR) through a simulation. Experimental results show that in terms of energy consumption for flash operation the grouped management of cache is not suitable and NUR algorithm is superior to LRU algorithm. In particular, we found that the cache hit ratio of LRU algorithm is about 10% point higher than that of NUR algorithm while the energy consumption of LRU algorithm is about 32% high.

• Environmental Engineering Research
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• v.11 no.3
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• pp.156-163
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• 2006

In this study, substrate removal characteristics were analyzed to reduce the cost of external carbon dosage at Sudokwon Landfill Site Management Corporation in Korea by utilizing oxygen uptake rate (OUR) and nitrate uptake rate (NUR) tests. To estimate and evaluate the substrate removal characteristics obtained by the batch tests, the lab-scale MLE process was operated. By-products of J Co. (sugar manufactory) and S Co. (fine chemical industry) were selected as the concerned carbon sources through a comparison of carbon and nitrogen contents. MeOH was tested as a control experiment. Until the steady state, the fraction of $RBDCOD_{OUR}$ concentration to COD concentration of J Co., S Co. by-products and MeOH increased and reached levels of 98%, 82%, and 100%, respectively. During the 20th operating day, the fraction of $RBDCOD_{NUR}$ concentration to COD concentration was 95%, 81%, and 83%, respectively. These fractions of $RBDCOD_{NUR}$ concentration to $RBDCOD_{OUR}$ concentration increased according to acclimation periods and reached levels of 99%, 97%, and 81%, respectively, on the 20th day. The results obtained from the lab-scale MLE process operation using the concerned carbon sources as external carbon were similar to that observed by OUR and NUR tests.

• Journal of the Korean GEO-environmental Society
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• v.5 no.4
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• pp.25-31
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• 2004

In conventional activated sludge process, COD fractions in wastewater are important parameters, significantly. Depending on characteristics of influent COD fractionation, activated sludge process requires a major change of a process operation to ensure meeting a stricter standards. In order to validate and evaluate the accuracy of the traditional COD fractionation methodologies, readily and slowly biodegradable COD was mixed using glucose and peptone as a sole carbon source in a synthetic wastewater, respectively. In this research, prediction of the COD fraction was made using the OUR(Oxygen Utilization Rate) and the NUR(Nitrate Utilization Rate) experiments. The result showed that COD fractions calculated by OUR experiment were similar to the composition of synthetic wastewater. On the other hand, it was found that an error was generated during the NUR experiment. This error was due to the intracellular storage period for storage microorganisms such as PAOs, and the error in COD fraction was observed about 8-14 % in terms of Total COD.

• Toxicological Research
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• v.23 no.3
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• pp.231-238
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• 2007

Evaluation of potentials of chemicals to alter expression of genes that are involved in carcinogenesis may serve useful tools in toxicological research. In this investigation, we developed reporter cell lines that expressed luciferase in response to transactivation of hypoxia inducible factor-1, P53 tumor suppressor and Nur77 of which roles have been well established in cancer development and progression. Whereas these reporter cell lines displayed low constitutive backgrounds, the reporter activities were significantly enhanced in response to $desferriosamine/CoCl_2$, adriamycin or 6-mercaptopurine, which are hypoxia mimicking chemicals, P53 activator or Nur77 inducer, respectively. The activation of the reporter was time- and dose-dependent. Known tumor initiators and promoters, such as phorbol 12-myristate 13-acetate and phorbol 12, 13-dicaprinate induced the reporter activity at as low as 10nM in these stable cell lines. Further, known anti-tumor promoters, such as ascorbic acid and ${\beta}-carotene$ repressed the reporter activities. These results indicate that our stable reporter cell lines could serve as a useful system for rapid assessment of carcinogenicity of toxic chemicals.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.138-138
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• 2003

Tributyltin (TBT) is also recognized as an endocrine disrupter. Organotin compounds such as TBT are widely used as agricultural biocides, and for antifouling paint of ship bottoms and of fishing nets. In this study, we investigated the role of nur 77 in induction of apoptosis in TBT-induced leydig cells.(omitted)

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.282-283
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• 2012

가상메모리 시스템에서 페이지 부재(page fault)를 최소화하기 위해서는 미래에 사용될 페이지를 미리 예측하는 것이 중요하다. 미래에 사용될 페이지는 이미 입력된 페이지들의 패턴 분석을 통해 예측 가능하며 이를 통해 시스템 성능을 최대화 할 수 있는 페이지 교체 정책(page replacement policy)에 대한 연구가 필요하다. 본 논문에서는 동일한 교체 우선권을 가지는 페이지들 간의 예측 적중률을 높이기 위하여 기존의 NUR(not used recently) 정책에 참조횟수 비트를 추가하여 우선 순위를 판단하는 방법을 제안한다. 제안하는 정책은 C 언어를 기반으로 모델링 되었으며 시뮬레이션 결과 페이지 프레임의 크기와 무관하게 기존의 정책들에 비해 성능이 향상됨을 확인하였다.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.11a
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• pp.168-168
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• 2002