• BMB Reports
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• 제37권2호
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• pp.139-143
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• 2004

The antioxidant responsive element (ARE) is a cis-acting regulatory element of genes encoding phase II detoxification enzymes and antioxidant proteins, such as NAD(P)H: quinone oxidoreductase 1, glutathione S-transferases, and glutamate-cysteine ligase. Interestingly, it has been reported that Nrf2 (NF-E2-related factor 2) regulates a wide array of ARE-driven genes in various cell types. Nrf2 is a basic leucine zipper transcription factor, which was originally identified as a binding protein of locus control region of ss-globin gene. The DNA binding sequence of Nrf2 and ARE sequence are very similar, and many studies demonstrated that Nrf2 binds to the ARE sites leading to up-regulation of downstream genes. The function of Nrf2 and its downstream target genes suggests that the Nrf2-ARE pathway is important in the cellular antioxidant defense system. In support of this, many studies showed a critical role of Nrf2 in cellular protection and anti-carcinogenicity, implying that the Nrf2-ARE pathway may serve as a therapeutic target for neurodegenerative diseases and cancers, in which oxidative stress is closely implicated.

• Journal of Veterinary Science
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• 제21권3호
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• pp.46.1-46.18
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• 2020

Background: High concentrations of particulate matter less than 2.5 ㎛ in diameter (PM2.5) in poultry houses is an important cause of respiratory disease in animals and humans. Pseudomonas aeruginosa is an opportunistic pathogen that can induce severe respiratory disease in animals under stress or with abnormal immune functions. When excessively high concentrations of PM2.5 in poultry houses damage the respiratory system and impair host immunity, secondary infections with P. aeruginosa can occur and produce a more intense inflammatory response, resulting in more severe lung injury. Objectives: In this study, we focused on the synergistic induction of inflammatory injury in the respiratory system and the related molecular mechanisms induced by PM2.5 and P. aeruginosa in poultry houses. Methods: High-throughput 16S rDNA sequence analysis was used for characterizing the bacterial diversity and relative abundance of the PM2.5 samples, and the effects of PM2.5 and P. aeruginosa stimulation on inflammation were detected by in vitro and in vivo. Results: Sequencing results indicated that the PM2.5 in poultry houses contained a high abundance of potentially pathogenic genera, such as Pseudomonas (2.94%). The lung tissues of mice had more significant pathological damage when co-stimulated by PM2.5 and P. aeruginosa, and it can increase the expression levels of interleukin (IL)-6, IL-8, and tumor necrosis factor-α through nuclear factor (NF)-κB pathway in vivo and in vitro. Conclusions: The results confirmed that poultry house PM2.5 in combination with P. aeruginosa could aggravate the inflammatory response and cause more severe respiratory system injuries through a process closely related to the activation of the NF-κB pathway.

• BMB Reports
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• 제39권5호
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• pp.479-491
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• 2006

Heme oxygenase (HO), the rate limiting enzyme in the breakdown of heme into carbon monoxide (CO), iron and bilirubin, has recently received overwhelming research attention. To date three mammalian HO isozymes have been identified, and the only inducible form is HO-1 while HO-2 and HO-3 are constitutively expressed. Advances in unveiling signal transduction network indicate that a battery of redox-sensitive transcription factors, such as activator protein-1 (AP-1), nuclear factor-kappa B (NF-${\kappa}B$) and nuclear factor E2-related factor-2 (Nrf2), and their upstream kinases including mitogen-activated protein kinases play an important regulatory role in HO-1 gene induction. The products of the HO-catalyzed reaction, particularly CO and biliverdin/bilirubin have been shown to exert protective effects in several organs against oxidative and other noxious stimuli. In this context, it is interesting to note that induction of HO-1 expression contributes to protection against liver damage induced by several chemical compounds such as acetaminophen, carbon tetrachloride and heavy metals, suggesting HO-1 induction as an important cellular endeavor for hepatoprotection. The focus of this review is on the significance of targeted induction of HO-1 as a potential therapeutic strategy to protect against chemically-induced liver injury as well as hepatocarcinogenesis.

• Biomolecules & Therapeutics
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• 제24권5호
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• pp.482-488
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• 2016

Cancer stem cells (CSCs) are a subset of tumor cells, which are characterized by resistance against chemotherapy and environmental stress, and are known to cause tumor relapse after therapy. A number of molecular mechanisms underlie the chemoresistance of CSCs, including high expression levels of drug efflux transporters. We investigated the role of the antioxidant transcription factor NF-E2-related factor 2 (NRF2) in chemoresistance development, using a CSC-enriched colonosphere system. HCT116 colonospheres were more resistant to doxorubicin-induced cell death and expressed higher levels of drug efflux transporters such as P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) compared to HCT116 monolayers. Notably, levels of NRF2 and expression of its target genes were substantially elevated in colonospheres, and these increases were linked to doxorubicin resistance. When NRF2 expression was silenced in colonospheres, Pgp and BCRP expression was downregulated, and doxorubicin resistance was diminished. Collectively, these results indicate that NRF2 activation contributes to chemoresistance acquisition in CSC-enriched colonospheres through the upregulation of drug efflux transporters.

• The Korean Journal of Physiology and Pharmacology
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• 제18권4호
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• pp.313-320
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• 2014

The study was conducted to investigate the role of vitamin E in the high altitude hypoxia-induced damage to the intestinal barrier in rats. Sprague-Dawley rats were divided into control (Control), high altitude hypoxia (HH), and high altitude hypoxia + vitamin E (250 mg/kg $BW^*d$) (HV) groups. After the third day, the HH and HV groups were placed in a hypobaric chamber at a stimulated elevation of 7000 m for 5 days. The rats in the HV group were given vitamin E by gavage daily for 8 days. The other rats were given equal volume saline. The results showed that high altitude hypoxia caused the enlargement of heart, liver, lung and kidney, and intestinal villi damage. Supplementation with vitamin E significantly alleviated hypoxia-caused damage to the main organs including intestine, increased the serum superoxide dismutase (SOD) (p< 0.05), diamino oxidase (DAO) (p< 0.01) levels, and decreased the serum levels of interleukin-2 (IL-2) (p< 0.01), interleukin-4 (IL-4) (p<0.001), interferon-gamma ($IFN-{\gamma}$) (p<0.01) and malondialdehyde (MDA) (p<0.001), and decreased the serum erythropoietin (EPO) activity (p<0.05). Administration of vitamin E significantly increased the S-IgA (p<0.001) in ileum and significantly improved the expression levels of occludin and $I{\kappa}B{\alpha}$, and decreased the expression levels of hypoxia-inducible factor 1 alpha and 2 alpha ($HIF-1{\alpha}$ and $HIF-2{\alpha}$), Toll-like receptors (TLR4), P-$I{\kappa}B{\alpha}$ and nuclear factor-${\kappa}B$ p65(NF-${\kappa}B$ P65) in ileum compared to the HH group. This study suggested that vitamin E protectis from intestinal injury caused by high altitude hypoxia environment. These effects may be related to the HIF and TLR4/NF-${\kappa}B$ signaling pathway.

• Biomolecules & Therapeutics
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• 제29권1호
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• pp.90-97
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• 2021

Ultraviolet B (UVB) radiation causes DNA base modifications. One of these changes leads to the generation of 8-oxoguanine (8-oxoG) due to oxidative stress. In human skin, this modification may induce sunburn, inflammation, and aging and may ultimately result in cancer. We investigated whether phloroglucinol (1,3,5-trihydroxybenzene), by enhancing the expression and activity of 8-oxoG DNA glycosylase 1 (Ogg1), had an effect on the capacity of UVB-exposed human HaCaT keratinocytes to repair oxidative DNA damage. Here, the effects of phloroglucinol were investigated using a luciferase activity assay, reverse transcription-polymerase chain reactions, western blot analysis, and a chromatin immunoprecipitation assay. Phloroglucinol restored Ogg1 activity and decreased the formation of 8-oxoG in UVB-exposed cells. Moreover, phloroglucinol increased Ogg1 transcription and protein expression, counteracting the UVB-induced reduction in Ogg1 levels. Phloroglucinol also enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) as well as Nrf2 binding to an antioxidant response element located in the Ogg1 gene promoter. UVB exposure inhibited the phosphorylation of protein kinase B (PKB or Akt) and extracellular signal-regulated kinase (Erk), two major enzymes involved in cell protection against oxidative stress, regulating the activity of Nrf2. Akt and Erk phosphorylation was restored by phloroglucinol in the UVB-exposed keratinocytes. These results indicated that phloroglucinol attenuated UVB-induced 8-oxoG formation in keratinocytes via an Akt/Erk-dependent, Nrf2/Ogg1-mediated signaling pathway.

• Archives of Plastic Surgery
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• 제41권6호
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• pp.654-660
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• 2014

Background Reactive oxygen species (ROS) damages cell molecules, and modifies cell signaling. The nuclear factor E2-related factor (Nrf2) is a critical transcription regulator, which protects cells against oxidative damage. Nrf2 expression is increased in a large number of cancers. However, little information has been reported regarding the expression of Nrf2 in skin cancers. Hence, we explored the expression of Nrf2 protein in skin cancers. Methods The Nrf2 protein expression in 24 specimens, including 6 malignant melanomas (MM), 6 squamous cell carcinomas (SCC), 6 basal cell carcinomas (BCC), and 6 normal skin tissues, was evaluated by western blotting. Immunohistochemical staining was performed. The expression of Kelch-like ECH-associated protein 1 (Keap1), the key regulator of Nrf2, was also analyzed by western blotting. Results Small interfering RNA transfection to the melanoma cell line G361 confirmed that an approximately 66 kDa band was the true Nrf2 band. The western blot revealed that the Nrf2 protein was definitely expressed in normal skin tissues, but the Nrf2 expression was decreased in MM, SCC, and BCC. Immunohistochemical examination showed that expression of Nrf2 was decreased in all skin cancer tissues compared to the normal skin tissues. Keap1 was not expressed in all malignant skin tumors and normal skin tissues by western blot. Conclusions ROS was increased in various types of cancers which proteins were highly expressed or underexpressed. This study demonstrated that the expression of Nrf2 protein was down-regulated in human malignant skin tumors. We suggest that decreased expression of Nrf2 is related to skin cancers.

• 한국식품영양과학회지
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• 제44권1호
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• pp.7-13
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• 2015

본 연구에서는 아로니아 열매 추출물(AF-H)의 항염증 활성을 조사하기 위하여 LPS 자극에 의해 유도된 RAW 264.7 macrophage의 염증반응에서 AF-H의 염증매개인자 및 염증성 사이토카인 분비 억제활성과 이에 관련된 세포 내 작용기전 해석을 수행하였다. LPS($1{\mu}g/mL$)로 RAW 264.7 세포를 24시간 자극하는 염증모델에서 세포독성을 나타내지 않는 안전한 농도의 AF-H($0{\sim}500{\mu}g/mL$)를 LPS 처리 12시간 전에 처리하여 NO 및 PGE2의 분비 억제활성을 측정하였다. 그 결과 AF-H 처리에 의해 NO와 PGE2의 생성이 처리 농도에 의존하여 유의하게 억제되었으며, 이들 염증매개인자의 생합성 효소인 iNOS 및 COX-2의 세포 내 발현도 현저하게 억제되는 것으로 관찰되었다. 또한 AF-H의 처리에 의해 염증성 사이토카인인 $TNF-{\alpha}$와 IL-6의 분비도 유의하게 억제되는 것으로 확인하였다. 이러한 AF-H에 의한 항염증 활성의 세포 내 기전을 해석하기 위하여 LPS 자극에 의해 유도되는 MAPK와 $NF-{\kappa}B$ 전사인자의 활성화에 대한 억제 효과를 조사하였다. 그 결과 AF-H는 MAPK의 인산화에는 별다른 영향을 미치지 않고 $NF-{\kappa}B$의 활성화($I{\kappa}B$ 인산화)를 효과적으로 억제하는 것으로 확인되었다. 한편 LPS에 의한 in vivo 패혈증 모델에서 AF-H에 의한 패혈증 억제활성을 측정한 결과 비록 통계학적으로 유의하지는 않으나 AF-H 투여에 의해 생존율과 50% 사망률의 연장 효과가 관찰되었다. 이들 결과를 종합해 보면 아로니아 열매 열수추출물은 $NF-{\kappa}B$의 활성화 억제를 통해 NO, PGE2, $TNF-{\alpha}$ 및 IL-6 등의 염증매개인자와 사이토카인의 생성을 억제하는 항염증 활성을 지니는 것으로 확인되었다.

• 생명과학회지
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• 제24권7호
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• pp.713-720
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• 2014

본 연구에서는 Ardisia arborescens 에탄올 추출물(AAEE)의 항산화능과 항염증 생리활성을 in vitro assay system 및 cell culture model system을 이용하여 분석하였다. 먼저 AAEE의 항산화능을 DPPH radical 소거능으로 분석한 결과 양성 대조군으로 사용한 ascorbic acid와 유사한 정도의 높은 활성을 보여 매우 강한 항산화능을 보유함을 확인하였다. 또한 RAW 264.7 세포주를 이용한 $H_2O_2$ 및 LPS의 유도에 의해 생성된 ROS에 대한 소거능을 분석한 결과에서도 농도의존적인 강한 소거능을 보였다. 뿐만 아니라 대표적인 항산화효소로 천연물에 의한 항산화능 활성에 의해 발현이 유도되는 HO-1, TrxR1 및 그 전사 인자인 Nrf2의 단백질 발현이 AAEE의 처리에 의해 농도의존적으로 증가됨을 보였으며 이러한 HO-1, TrxR1 및 Nrf2의 발현 변화는 상위신호전달계인 MAPKs에 의해 조절될 가능성을 보였다. 한편 AAEE가 LPS에 의해 유도된 NO 생성에 미치는 영향을 분석한 결과 세포독성 없이 농도의존적인 NO 생성 저해능을 보였으며 이는 NO 생성 단백질인 iNOS의 발현 저해에서 기인함을 확인하였다. 이와 같은 AAEE의 NO 생성 억제 효과는 염증 상위신호전달계인 NF-${\kappa}B$ 및 AP-1의 조절을 통해 일어날 가능성을 보였다. 이러한 결과를 통해 AAEE의 높은 항산화능과 항염증 활성을 처음으로 확인하였으며 향후 기능성 소재로서 유용하게 활용될 수 있을 것으로 판단된다.

• 대한본초학회지
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• 제26권1호
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• pp.87-96
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• 2011

Objectives : The aerial parts of Rumex japonicus Houtt. (RF) is used by traditional clinics to treat parasite infection in East asia. This study aims a verification of anti-oxidative and anti-inflammatory effects of RF methanol extract. Methods : Anti-oxidative effects of RF were measured by scavenging activities of DPPH, superoxide, nitric oxide (NO) and peroxynitrite radicals. And also scavenging activities of anti-oxidation in lipopolysaccharide (LPS)-treated RAW 264.7 cells were measured. The inhibitory effects against the production of inflammatory mediators including NO, prostaglandin $E_2$ ($PGE_2$), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-$1{\beta}$ (IL-$1{\beta}$), IL-6, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and the translocation of nuclear factor (NF)-${\kappa}B$ in LPS-stimulated RAW 264.7 cells by RF were tested. Results : RF scavenged DPPH, superoxide, NO and peroxynitrite radicals, and RF (at $200{\mu}g/m{\ell}$) reduced the inflammatory mediators definitely. Conclusions : These results indicate that RF may be a potential drug source for oxidative stress related inflammatory diseases.