• Journal of Life Science
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• v.21 no.4
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• pp.486-493
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• 2011

Nitric oxide (NO) donors are a potent inducer of heme oxygenase-1 (HO-1). However, it is unclear whether or not HO-1 expression induced by NO donors is a direct consequence of NO released by NO donors. Here, we investigated the effects of NO donors on the expression of HO-1 in primary rat articular chondrocytes. NO donors (SIN-1, SNAP, and SNP) significantly induced the accumulation of HO-1 protein accompanied by an increase in HO-1 mRNA. NO donor-induced HO-1 expression exerted cytoprotection against NO and/or superoxide-induced cell death. Guanylate cyclase signaling was not associated with Nrf2 and HO-1 expression in NO donor-treated chondrocytes. Interestingly, NO scavenger carboxy-PTIO and SOD mimetic TEMPOL markedly inhibited NO donor-induced HO-1 expression in chondrocytes. In addition, NO donor-induced HO-1 expression was completely abrogated by the peroxynitrite scavenger MnTBAP. Since peroxynitrite can be physiologcally formed in the cell through reaction of NO with superoxide, we analyzed whether or not peroxynitrite could directly induce HO-1 expression in chondrocytes. Peroxynitrite treatment in chondrocytes evoked doseand time-dependent Nrf2 and HO-1 expression. These results indicate that HO-1 expression induced by NO donors in rat articular chondrocytes is due to NO-mediated peroxynitrite rather than NO.

• Molecules and Cells
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• v.42 no.9
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• pp.672-685
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• 2019

Currently, liver transplantation is the only available remedy for patients with end-stage liver disease. Conservation of transplanted liver graft is the most important issue as it directly related to patient survival. Carbonyl reductase 1 (CBR1) protects cells against oxidative stress and cell death by inactivating cellular membrane-derived lipid aldehydes. Ischemia-reperfusion (I/R) injury during living-donor liver transplantation is known to form reactive oxygen species. Thus, the objective of this study was to investigate whether CBR1 transcription might be increased during liver I/R injury and whether such increase might protect liver against I/R injury. Our results revealed that transcription factor Nrf2 could induce CBR1 transcription in liver of mice during I/R. Pre-treatment with sulforaphane, an activator of Nrf2, increased CBR1 expression, decreased liver enzymes such as aspartate aminotransferase and alanine transaminase, and reduced I/R-related pathological changes. Using oxygen-glucose deprivation and recovery model of human normal liver cell line, it was found that oxidative stress markers and lipid peroxidation products were significantly lowered in cells overexpressing CBR1. Conversely, CBR1 knockdown cells expressed elevated levels of oxidative stress proteins compared to the parental cell line. We also observed that Nrf2 and CBR1 were overexpressed during liver transplantation in clinical samples. These results suggest that CBR1 expression during liver I/R injury is regulated by transcription factor Nrf2. In addition, CBR1 can reduce free radicals and prevent lipid peroxidation. Taken together, CBR1 induction might be a therapeutic strategy for relieving liver I/R injury during liver transplantation.

• BMB Reports
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• v.45 no.6
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• pp.348-353
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• 2012

L-2-Oxothiazolidine-4-carboxylic acid (OTC) is a cysteine prodrug that maintains glutathione in tissues. The present study was designed to investigate anti-fibrotic and anti-oxidative effects of OTC via modulation of nuclear factor erythroid 2-related factor 2 (Nrf2) in an in vivo thioacetamide (TAA)-induced hepatic fibrosis model. Treatment with OTC (80 or 160 mg/kg) improved serum liver function parameters and significantly ameliorated liver fibrosis. The OTC treatment groups exhibited significantly lower expression of ${\alpha}$-smooth muscle actin, transforming growth factor-${\beta}1$, and collagen ${\alpha}1$ mRNA than that in the TAA model group. Furthermore, the OTC treatment groups showed a significant decrease in hepatic malondialdehyde level compared to that in the TAA model group. Nrf2 and heme oxygenase-1 expression increased significantly in the OTC treatment groups compared with that in the TAA model group. Taken together, these results suggest that OTC restores the anti-oxidative system by upregulating Nrf2; thus, ameliorating liver injury and a fibrotic reaction.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.236-245
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• 2018

Ingredients of soy and fermented soy products have been widely utilized as food supplements for health-enhancing properties. The aim of this study was to evaluate the effects of fermented soymilk (FSM) and soymilk (SM) on free fatty acid-induced lipogenesis in the hepatocellular steatosis model. HepG2 cells were incubated with palmitic acid (PA) for 24 h to induce lipogenesis and accumulation of intracellular lipid contents. The PA-treated cells were co-incubated with FSM, SM, genistein, and estrogen, respectively. Lipid accumulation in the PA-treated HpG2 cells was significantly decreased by co-incubation with FSM. Treatment of HepG2 cells with PA combined with genistein or estrogen significantly increased the expression of SREBP-1. However, FSM co-incubation significantly attenuated SREBP-1 expression in the PA-treated HepG2 cells; in addition, expression of NRF-2 and phosphorylation of ERK were significantly increased in the PA and FSM co-incubated cells. PA-induced ROS production was significantly reduced by FSM and SM. Our results suggested that the bioactive components of FSM could protect hepatocytes against the lipid accumulation and ROS production induced by free fatty acids. These effects may be mediated by the inhibition of SREBP-1 and the activation of NRF-2 via the ERK pathway in HepG2 cells.

• The Korean Journal of Pain
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• v.33 no.3
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• pp.216-225
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• 2020

Background: Garlic oil is a rich source of organosulfur compounds including diallyl disulfide and diallyl trisulfide. There have been studies showing the neuroprotective actions of these organosulfur compounds. However, the potential of these organosulfur compounds in neuropathic pain has not been explored. The present study was aimed at investigating the pain attenuating potential of diallyl disulfide and diallyl trisulfide in chronic constriction injury (CCI)-induced neuropathic pain in rats. The study also explored their pain-attenuating mechanisms through modulation of H₂S, brain-derived neurotrophin factor (BDNF) and nuclear factor erythroid 2-related factor 2 (Nrf2). Methods: The rats were subjected to CCI injury by ligating the sciatic nerve in four places. The development of neuropathic pain was measured by assessing mechanical hyperalgesia (Randall-Selittotest), mechanical allodynia (Von Frey test), and cold allodynia (acetone drop test) on 14th day after surgery. Results: Administration of diallyl disulfide (25 and 50 mg/kg) and diallyl trisulfide (20 and 40 mg/kg) for 14 days led to a significant reduction in pain in CCI-subjected rats. Moreover, treatment with these organosulfur compounds led to the restoration of H₂S, BDNF and Nrf2 levels in the sciatic nerve and dorsal root ganglia. Co-administration of ANA-12 (BDNF blocker) abolished pain attenuating actions as well as BDNF and the Nrf2 restorative actions of diallyl disulfide and diallyl trisulfide, without modulating H₂S levels. Conclusions: Diallyl disulfide and diallyl trisulfide have the potential to attenuate neuropathic pain in CCI-subjected rats possibly through activation of H₂S-BDNF-Nrf2 signaling pathway.

• Journal of Life Science
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• v.21 no.7
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• pp.997-1003
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• 2011

Menopause and obesity are associated with metabolism. The purpose of this study was to examine the changes of PPAR${\gamma}$, PGC-1(${\alpha},\;{\beta}$), NRf-1 and TFAM mRNA and mitochondria biogenesis in adipocytes and investigate the effect of swimming exercise for 6weeks on ovariectomized rats. Rats were randomly assigned to 3 groups: (1) ovariectomized rats fed with a control diet (C, n=4), (2) ovariectomized rats fed with high fat diet (H, n=4), and (3) ovariectomized rats trained to exercise and fed with high fat diet (H+EX, n=4). Exercise was performed by swimming for 5 days/wk, with a progressive increase in exercise over the course of 6 weeks. Results showed that the fat tissue weight in the H group was markedly increased (p<0.01) compared to other groups, however, regular exercise significantly decreased fat weight. The PPAR-${\gamma}$ (p<0.05), PGC-$1{\alpha}$ (p<0.01), -$1{\beta}$ (p<0.05), NRf-1 (p<0.01) and TFAM (p<0.05) mRNA expression in the adipocytes of H+EX were higher than in the H group. These results suggest that regular exercise for 6 weeks might exert positive effects by increasing PPAR-${\gamma}$, PGC-1 (${\alpha},\;{\beta}$), NRf-1 and TFAM mRNA expression and mitochondria in adipocytes. Thus, regular exercise may be helpful in the improvement of mitochondria biogenesis function in obese, ovariectomized rats.

• Animal Bioscience
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• v.34 no.4
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• pp.652-661
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• 2021

Objective: Wooden breast (WB) is a novel myopathy affecting modern broiler chickens, which causes substantial economic losses in the poultry industry. The objective of this study was to evaluate the effect of WB abnormality on meat quality, redox status, as well as the expression of genes of the nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway. Methods: A total of 80 broilers (Ross 308, 42 days of age, about 2.6 kg body weight) raised at Jiujin farm (Suqian, Jiangsu, China) were used. Twelve unaffected (no detectable hardness of the breast area) and twelve WB-affected (diffuse remarkable hardness in the breast muscle) birds were selected from the commercial broiler farm according to the criteria proposed by previous studies. Results: The results indicated that WB showed histological lesions characterized by fiber degeneration and fibrosis, along with an increase of muscle fiber diameter (p<0.05). Moreover, higher pH value, lightness, yellowness, drip loss and cooking loss were observed in the WB group (p<0.05). Compared with the normal breast (NOR) group, the WB group showed higher formation of reactive oxygen species (p<0.05), increased level of oxidation products and antioxidant activities (p<0.05), accompanied with mitochondrial damages and lower mitochondrial membrane potential (p<0.05). Meanwhile, the relative mRNA expressions of Nrf2 and its downstream antioxidant genes including heme oxygenase-1, NAD(P)H qui none dehydrogenase 1, glutathione peroxidase, superoxide dismutase, and glutamate-cysteine ligase were higher than those of the NOR group (p<0.05). Conclusion: In conclusion, WB myopathy impairs meat quality by causing oxidative damages and mitochondrial dysfunction in broilers, even though the activated Nrf2/antioxidant response element pathway provides protection for the birds.

• Biomolecules & Therapeutics
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• v.31 no.6
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• pp.648-654
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• 2023

Oxidative stress-induced melanocyte apoptosis is linked to the immune system and plays a critical role in the pathogenesis of vitiligo. Aquaporin-3 (AQP3), which is downregulated in vitiligo keratinocytes, regulates intracellular H₂O₂ accumulation. However, the role of AQP3 in oxidative stress is uncertain in vitiligo. This study investigated the effect of downregulated AQP3 on oxidative stress in vitiligo using lesional and non-lesional skin specimen sets from vitiligo patients and primary cultured adult normal human epidermal keratinocytes, with or without downregulation and overexpression of AQP3 in the presence or absence of H₂O₂ treatment. The levels of nuclear factor E2-related factor 2 (NRF2) and/or its main target, NAD(P)H quinone dehydrogenase 1 (NQO-1), were lower in the lesional keratinocytes and cultured keratinocytes with AQP3 knockdown, but were increased in keratinocytes upon AQP3 overexpression. Ratios of NRF2 nuclear translocation and NQO-1 expression levels were further reduced in AQP3-knockdown keratinocytes following H₂O₂ treatment. The conditioned media from AQP3-knockdown keratinocytes treated with H₂O₂ contained higher concentrations of reactive oxygen species (ROS). Moreover, the number of viable melanocytes was reduced when the conditioned media were added to the culture media. Overall, AQP3 downregulation in the keratinocytes of patients with vitiligo can induce oxidative stress in neighboring melanocytes, leading to melanocyte death.

• Biomolecules & Therapeutics
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• v.28 no.2
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• pp.163-171
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• 2020

Silibinin exhibits antidiabetic potential by preserving the mass and function of pancreatic β-cells through up-regulation of estrogen receptor-α (ERα) expression. However, the underlying protective mechanism of silibinin in pancreatic β-cells is still unclear. In the current study, we sought to determine whether ERα acts as the target of silibinin for the modulation of antioxidative response in pancreatic β-cells under high glucose and high fat conditions. Our in vivo study revealed that a 4-week oral administration of silibinin (100 mg/kg/day) decreased fasting blood glucose with a concurrent increase in levels of serum insulin in high-fat diet/streptozotocin-induced type 2 diabetic rats. Moreover, expression of ERα, NF-E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in pancreatic β-cells in pancreatic islets was increased by silibinin treatment. Accordingly, silibinin (10 μM) elevated viability, insulin biosynthesis, and insulin secretion of high glucose/palmitate-treated INS-1 cells accompanied by increased expression of ERα, Nrf2, and HO-1 as well as decreased reactive oxygen species production in vitro. Treatment using an ERα antagonist (MPP) in INS-1 cells or silencing ERα expression in INS-1 and NIT-1 cells with siRNA abolished the protective effects of silibinin. Our study suggests that silibinin activates the Nrf2-antioxidative pathways in pancreatic β-cells through regulation of ERα expression.

• Journal of Ginseng Research
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• v.35 no.3
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• pp.352-359
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• 2011

Korean red ginseng (KRG) is used worldwide as a popular traditional herbal medicine. KRG has shown beneficial effects on cardiovascular diseases, such as atherosclerosis, diabetes, and hypertension. Up-regulation of a cytoprotective protein, heme oxygenase (HO)-1, is considered to augment the cellular defense against various agents that may induce cytotoxic injury. In the present study, we demonstrate that KRG water extract induces HO-1 expression in human umbilical vein endothelial cells (HUVECs) and possible involvement of the anti-oxidant transcription factor nuclear factor-eythroid 2-related factor 2 (Nrf2). KRG-induced HO-1 expression was examined by western blots, reverse transcriptase polymerase chain reaction and immunofluorescence staining. Specific silencing of Nrf2 genes with Nrf2-siRNA in HUVECs abolished HO-1 expression. In addition, the HO inhibitor zinc protoporphyrin blunted the preventive effect of KRG on $H_2O_2$-induced cell death, as demonstrated by terminal transferase dUTP nick end labeling assay. Taken together, these results suggest that KRG may exert a vasculoprotective effect through Nrf2-mediated HO-1 induction in human endothelial cell by inhibition of cell death.