• Asian-Australasian Journal of Animal Sciences
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• 제30권5호
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• pp.728-735
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• 2017

Objective: This study was performed to reveal the molecular structure and expression patterns of horse glutamate-cysteine ligase catalytic subunit (GCLC) and glutamate-cysteine ligase modifier subunit (GCLM) genes whose products form glutamate cysteine ligase, which were identified as differentially expressed genes in the previous study. Methods: We performed bioinformatics analyses, and gene expression assay with quantitative polymerase chain reaction (qPCR) for horse GCLC and GCLM genes in muscle and blood leukocytes of Thoroughbred horses Results: Expression of GCLC showed the same pattern in both blood and muscle tissues after exercise. Expression of GCLC increased in the muscle and blood of Thoroughbreds, suggesting a tissue-specific regulatory mechanism for the expression of GCLC. In addition, expression of the GCLM gene increased after exercise in both the blood and muscle of Thoroughbreds. Conclusion: We established the expression patterns of GCLC and GCLM in the skeletal muscle and blood of Thoroughbred horses in response to exercise. Further study is now warranted to uncover the functional importance of these genes in exercise and recovery in racehorses.

• Toxicological Research
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• 제22권1호
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• pp.39-45
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• 2006

As the antioxidant and free radical scavenger, glutathione (GSH) participates in the preservation of cellular redox status and defense against reactive oxygen species and xenobiotics. Glutamate-cysteine ligase (GCL; also known as ${\gamma}$-glutamylcysteine synthetase, EC 6.3.2.2) is the rate limiting enzyme in GSH synthesis. In the present study, the accurate method for determination of GCL activity in crude liver extracts was developed by measuring both ${\gamma}$-glutamylcysteine and GSH from cysteine in the presence of glutamate, glycine and an ATP-generating system. We added glycine to promote the conversion of ${\gamma}$-glutamylcysteine to GSH, and to minimize the possibility of ${\gamma}$-glutamylcysteine metabolism to cysteine and oxoproline by ${\gamma}$-glutamylcyclotransferase. We established optimal conditions and substrate concentrations for the enzyme assay, and verified that inhibition of GCL by GSH did not interfere with this assay. Therefore, this assay of hepatic GCL under optimal conditions could provide a more accurate measurement of this enzyme activity in the crude liver extracts.

• Biomolecules & Therapeutics
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• 제25권4호
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• pp.427-433
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• 2017

Previously, we demonstrated that galangin (3,5,7-trihydroxyflavone) protects human keratinocytes against ultraviolet B (UVB)-induced oxidative damage. In this study, we investigated the effect of galangin on induction of antioxidant enzymes involved in synthesis of reduced glutathione (GSH), and investigated the associated upstream signaling cascades. By activating nuclear factor-erythroid 2-related factor (Nrf2), galangin treatment significantly increased expression of glutamate-cysteine ligase catalytic subunit (GCLC) and glutathione synthetase (GSS). This activation of Nrf2 depended on extracellular signal-regulated kinases (ERKs) and protein kinase B (AKT) signaling. Inhibition of GSH in galangin-treated cells attenuated the protective effect of galangin against the deleterious effects of UVB. Our results reveal that galangin protects human keratinocytes by activating ERK/AKT-Nrf2, leading to elevated expression of GSH-synthesizing enzymes.

• Animal Bioscience
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• 제35권2호
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• pp.166-176
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• 2022

Objective: Sperm is particularly susceptible to reactive oxygen species (ROS) stress. Glutathione (GSH) is an endogenous antioxidant that regulates sperm redox homeostasis. However, it is not clear whether boar sperm could utilize cysteine for synthesis GSH to protect sperm quality from ROS damage. Therefore, the present study was undertaken to elucidate the mechanism of how cysteine is involved in protecting boar sperm quality during liquid storage. Methods: Sperm motility, membrane integrity, lipid peroxidation, 4-hydroxyIlonenal (4-HNE) modifications, mitochondrial membrane potential, as well as the levels of ROS, GSH, and, ATP were evaluated. Moreover, the enzymes (GCLC: glutamate cysteine ligase; GSS: glutathione synthetase) that are involved in glutathione synthesis from cysteine precursor were detected by western blotting. Results: Compared to the control, addition of 1.25 mM cysteine to the liquid storage significantly increased boar sperm progressive motility, straight-line velocity, curvilinear velocity, beat-cross frequency, membrane integrity, mitochondrial membrane potential, ATP level, acrosome integrity, activities of superoxide dismutase and catalase, and GSH level, while reducing the ROS level, lipid peroxidation and 4-HNE modifications. It was also observed that the GCLC and GSS were expressed in boar sperm. Interestingly, when we used menadione to induce sperm with ROS stress, the menadione associated damages were observed to be reduced by the cysteine supplementation. Moreover, compared to the cysteine treatment, the γ-glutamylcysteine synthetase (γ-GCS) activity, GSH level, mitochondrial membrane potential, ATP level, membrane integrity and progressive motility in boar sperm were decreased by supplementing with an inhibitor of GSH synthesis, buthionine sulfoximine. Conclusion: These data suggest that boar sperm could biosynthesize the GSH from cysteine in vitro. Therefore, during storage, addition of cysteine improves boar sperm quality via enhancing the GSH synthesis to resist ROS stress.

• Toxicological Research
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• 제24권4호
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• pp.281-287
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• 2008

Impairment of hepatic metabolism of sulfur-containing amino acids has been known to be linked with induction of liver injury. We determined the early changes in the transsulfuration reactions in liver of rats challenged with a toxic dose of $CCl_4$ (2 mmol/kg, ip). Both hepatic methionine concentration and methionine adenosyltransferase activity were increased, but S-adenosylmethionine level did not change. Hepatic cysteine was increased significantly from 4 h after $CCl_4$ treatment. Glutathione (GSH) concentration in liver was elevated in $4{\sim}8$ h and then returned to normal in accordance with the changes in glutamate cysteine ligase activity. Cysteine dioxygenase activity and hypotaurine concentration were also elevated from 4 h after the treatment. However, plasma GSH concentration was increased progressively, reaching a level at least several fold greater than normal in 24 h. ${\gamma}$-Glutamyltransferase activity in kidney or liver was not altered by $CCl_4$, suggesting that the increase in plasma GSH could not be attributed to a failure of GSH cycling. The results indicate that acute liver injury induced by $CCl_4$ is accompanied with extensive alterations in the metabolomics of sulfurcontaining amino acids and related substances. The major metabolites and products of the transsulfuration pathway, including methionine, cysteine, hypotaurine, and GSH, are all increased in liver and plasma. The physiological significance of the change in the metabolomics of sulfur-containing substances and its role in the induction of liver injury need to be explored in future studies.

• Animal Bioscience
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• 제34권8호
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• pp.1403-1414
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• 2021

Objective: This study explored the mechanism of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway under conditions of zearalenone (ZEA)-induced oxidative stress in the duodenum of post-weaning gilts. Methods: Forty post-weaning gilts were randomly allocated to four groups and fed diets supplemented with 0, 0.5, 1.0, or 1.5 mg/kg ZEA. Results: The results showed significant reductions in the activity of the antioxidant enzymes total superoxide dismutase and glutathione peroxidase and increases the malondialdehyde content with increasing concentrations of dietary ZEA. Immunohistochemical analysis supported these findings by showing a significantly increased expression of Nrf2 and glutathione peroxidase 1 (GPX1) with increasing concentrations of ZEA. The relative mRNA and protein expression of Nrf2, GPX1 increased linearly (p<0.05) and quadratically (p<0.05), which was consistent with the immunohistochemical results. The relative mRNA expression of Keap1 decreased linearly (p<0.05) and quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet. The relative mRNA expression of modifier subunit of glutamate-cysteine ligase (GCLM) increased quadratically (p<0.05) in all ZEA treatment groups and the relative mRNA expression of quinone oxidoreductase 1 (NQO1) catalytic subunit of glutamate-cysteine ligase decreased linearly (p<0.05) and quadratically (p<0.05) in the ZEA1.0 group and ZEA1.5 group. The relative protein expression of Keap1 and GCLM decreased quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet, respectively. The relative protein expression of NQO1 increased linearly (p<0.05) and quadratically (p<0.05) in all ZEA treatment groups in the duodenum. Conclusion: These findings suggest that ZEA regulates the expression of key factors of the Keap1-Nrf2 signaling pathway in the duodenum, which enables resistance to ZEA-induced oxidative stress. Further studies are needed to examine the effects of ZEA induced oxidative stress on other tissues and organs in post-weaning gilts.

• Preventive Nutrition and Food Science
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• 제22권2호
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• pp.118-123
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• 2017

This study was conducted to investigate the anti-adipogenic activity of esculetin (ECT) which is reported to be attributable to the modulation of antioxidant enzymes during adipogenesis. After six days of ECT treatment of 3T3-L1 cells, lipid accumulation was determined by Oil red O staining. The levels of glutathione (GSH) and reactive oxygen species (ROS), and the activities of antioxidant enzymes including glutathione reductase, glutathione peroxidase (GPx), and catalase were examined. In addition, the protein expression of glutamate-cysteine ligase catalytic subunit (GCLC) and heme oxygenase-1 (HO-1) was measured by Western blot. ECT significantly inhibited lipid accumulation by approximately 80% and ROS production in a concentration-dependent manner. GSH level and GPx activity were increased by ECT by approximately 1.3-fold and 1.7-fold compared to the control group, respectively. GCLC and HO-1 expression were elevated by ECT. These results showed that ECT treatments strongly inhibit adipogenesis, increase GSH level, and upregulate the expression of GCLC and HO-1, possibly by decreasing ROS production in 3T3-L1 cells during adipogenesis.

• Environmental Analysis Health and Toxicology
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• 제24권1호
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• pp.53-61
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• 2009

사람 기관지상피세포주인 BEAS-2B에 담배연기농축액(CSC)을 처리하여 유도된 1198 세포주는 대조군 세포주인 1799에 비해 현저하게 낮은 glutathione 농도와 낮은 glutamate-cysteine ligase(GCL), glutathione peroxidase(GPx), glucose-6-phosphate dehydrogenase(G6PD), catalase 효소활성을 보였다. 두 세포주를 포도당 존재 하에서 4시간 hypoxia 처리 후 reoxygenation 하면서 시간에 따른 세포의 항산화계 활성을 측정한 결과, 1799 세포주에서는 의미 있는 변화가 관찰되지 않은 반면, 1198 세포주에서는 hypoxia 처리에 의해 glutathione의 농도 및 GSH/GSSG 비와 G6PD 활성이 감소되었고, reoxygenation 기에는 GPx, glutathione reductase(GRd), G6PD, superoxide dismutase 활성이 감소되었다. 그러나 reoxygenation 2시간 이후에는 GRd와 G6PD 활성의 회복이 관찰되었으며, 그 결과 GSH/GSSG 비율이 회복되었다. 이 실험 결과는 CSC가 능력을 현저히 저하시킬 수 있음을 보여준다. Glutathione은 hypoxia-reoxygenation에 의한 산화적 스트레스 하에서 항산화제로서의 역할뿐 아니라, 세포 내 GSH/GSSG 비의 변화를 통해 산화적 스트레스에 대한 항산화계의 적응 반응 여부를 결정하는 중요한 인자로 작용할 것으로 보여진다.

• 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.

• Nutrition Research and Practice
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• 제8권3호
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• pp.272-277
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• 2014

BACKGROUND/OBJECTIVES: This study investigated the antioxidant activities and hepatoprotective effects of Schisandra chinensis Baillon extract (SCE) against tert-butyl hydroperoxide (t-BHP)-induced oxidative hepatic damage in rats. MATERIALS/METHODS: Sprague-Dawley (SD) rats were pretreated with SCE (300, 600, and 1,200 mg/kg BW) or saline once daily for 14 consecutive days. On day 14, each animal, except those belonging to the normal control group, were injected with t-BHP (0.8 mmol/kg BW/i.p.), and all of the rats were sacrificed 16 h after t-BHP injection. RESULTS: Although no significant differences in AST and ALT levels were observed among the TC and SCE groups, the high-dose SCE group showed a decreasing tendency compared to the TC group. However, erythrocyte SOD activity showed a significant increase in the low-dose SCE group compared with the TC group. On the other hand, no significant differences in hepatic total glutathione (GSH) level, glutathione reductase (GR), and glutathione peroxidase (GSH-Px) activities were observed among the TC and SCE groups. Hepatic histopathological evaluation revealed that pretreatment with SCE resulted in reduced t-BHP-induced incidence of lesions, such as neutrophil infiltration, swelling of liver cells, and necrosis. In particular, treatment with a high dose of SCE resulted in induction of phase II antioxidant/detoxifying enzyme expression, such as glutathione S-transferase (GST) and glutamate-cysteine ligase catalytic subunit (GCLC). CONCLUSIONS: Based on these results, we conclude that SCE exerts protective effects against t-BHP induced oxidative hepatic damage through the reduction of neutrophil infiltration, swelling of liver cells, and necrosis. In addition, SCE regulates the gene expression of phase II antioxidant/detoxifying enzymes independent of hepatic antioxidant enzyme activity.