• Biomolecules & Therapeutics
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• v.32 no.1
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• pp.77-83
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• 2024

Alzheimer's disease (AD) is a neurodegenerative disease characterized by neuronal cell death and memory impairment. Corticosterone (CORT) is a glucocorticoid hormone produced by the hypothalamic-pituitary-adrenal axis in response to a stressful condition. Excessive stress and high CORT levels are known to cause neurotoxicity and aggravate various diseases, whereas mild stress and low CORT levels exert beneficial actions under pathophysiological conditions. However, the effects of mild stress on AD have not been clearly elucidated yet. In this study, the effects of low (3 and 30 nM) CORT concentration on Aβ_25-35-induced neurotoxicity in SH-SY5Y cells and underlying molecular mechanisms have been investigated. Cytotoxicity caused by Aβ_25-35 was significantly inhibited by the low concentration of CORT treatment in the cells. Furthermore, CORT pretreatment significantly reduced Aβ_25-35-mediated pro-apoptotic signals, such as increased Bim/Bcl-2 ratio and caspase-3 cleavage. Moreover, low concentration of CORT treatment inhibited the Aβ_25-35-induced cyclooxygenase-2 and pro-inflammatory cytokine expressions, including tumor necrosis factor-α and interleukin-1β. Aβ_25-35 resulted in intracellular accumulation of reactive oxygen species and lipid peroxidation, which were effectively reduced by the low CORT concentration. As a molecular mechanism, low CORT concentration activated the nuclear factor-erythroid 2-related factor 2, a redox-sensitive transcription factor mediating cellular defense and upregulating the expression of antioxidant enzymes, such as NAD(P)H:quinone oxidoreductase, glutamylcysteine synthetase, and manganese superoxide dismutase. These findings suggest that low CORT concentration exerts protective actions against Aβ_25-35-induced neurotoxicity and might be used to treat and/or prevent AD.

• Molecules and Cells
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• v.38 no.5
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• pp.396-401
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• 2015

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important redox-sensitive transcription factor that regulates the expression of several cytoprotective genes. More recently, genetic analyses of human tumors have indicated that Nrf2 may cause resistance to chemotherapy. In this study, we found that the expression levels of Nrf2 and its target genes GCLC, HO-1, NQO1 were significantly higher in cisplatin-resistant A549 (A549/CDDP) cells than those in A549 cells, and this resistance was partially reversed by Nrf2 siRNA. 3,4,5,5,7-Pentamethoxyflavone (PMF), a natural flavon extracted from Rutaceae plants, sensitized A549/CDDP to CDDP and substantially induced apoptosis compared with that of CDDP alone treated group, and this reversal effect decreased when Nrf2 was downregulated by siRNA. Mechanistically, PMF reduced Nrf2 expression leading to a reduction of Nrf2 downstream genes, and in contrast, this effect was decreased by blocking Nrf2 with siRNA. Taken together, these results demonstrated that PMF could be used as an effective adjuvant sensitizer to increase the efficacy of chemotherapeutic drugs by downregulating Nrf2 signaling pathway.

• BMB Reports
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• v.53 no.4
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• pp.218-222
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• 2020

Excessive and hyperactive osteoclast activity causes bone diseases such as osteoporosis and periodontitis. Thus, the regulation of osteoclast differentiation has clinical implications. We recently reported that dehydrocostus lactone (DL) inhibits osteoclast differentiation by regulating a nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), but the underlying mechanism remains to be elucidated. Here we demonstrated that DL inhibits NFATc1 by regulating nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and nuclear factor-erythroid 2-related factor 2 (Nrf2). DL attenuated IκBα phosphorylation and p65 nuclear translocation as well as decreased the expression of NF-κB target genes and c-Fos. It also inhibited c-Jun N-terminal kinase (JNK) but not p38 or extracellular signal-regulated kinase. The reporter assay revealed that DL inhibits NF-κB and AP-1 activation. In addition, DL reduced reactive oxygen species either by scavenging them or by activating Nrf2. The DL inhibition of NFATc1 expression and osteoclast differentiation was less effective in Nrf2-deficient cells. Collectively, these results suggest that DL regulates NFATc1 by inhibiting NF-κB and AP-1 via down-regulation of IκB kinase and JNK as well as by activating Nrf2, and thereby attenuates osteoclast differentiation.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.3
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• pp.229-236
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• 2016

Resveratrol (RSV) may provide numerous protective effects against chronic inflammatory diseases. Due to local hypoxia and hypertonicity, the renal medulla is subject to extreme oxidative stress, and aldehyde products formed during lipid peroxidation, such as 4-hydroxy-2-hexenal (HHE), might be responsible for tubular injury. This study aimed at investigating the effects of RSV on renal and its signaling mechanisms. While HHE treatment resulted in decreased expression of Sirt1, AQP2, and nuclear factor erythroid 2-related factor 2 (Nrf2), mouse cortical collecting duct cells (M1) cells treated with HHE exhibited increased activation of p38 MAPK, extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and increased expression of NOX4, $p47^{phox}$, Kelch ECH associating protein 1 (Keap1) and COX2. HHE treatment also induced $NF-{\kappa}B$ activation by promoting $I{\kappa}B-{\alpha}$ degradation. Meanwhile, the observed increases in nuclear $NF-{\kappa}B$, NOX4, $p47^{phox}$, and COX2 expression were attenuated by treatment with Bay 117082, N-acetyl-l-cysteine (NAC), or RSV. Our findings indicate that RSV inhibits the expression of inflammatory proteins and the production of reactive oxygen species in M1 cells by inhibiting $NF-{\kappa}B$ activation.

• Nutrition Research and Practice
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• v.13 no.3
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• pp.205-213
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• 2019

BACKGROUND/OBJECTIVES: Myocardial infarction (MI) is caused by extensive myocardial damage attributed to the occlusion of coronary arteries. Our previous study in a rat model of ischemia/reperfusion (I/R) demonstrated that administration of arabinoxylan (AX), comprising arabinose and xylose, protects against myocardial injury. In this study, we undertook to investigate whether psyllium seed husk (PSH), a safe dietary fiber containing a high level of AX (> 50%), also imparts protection against myocardial injury in the same rat model. MATERIALS/METHODS: Rats were fed diets supplemented with PSH (1, 10, or 100 mg/kg/d) for 3 d. The rats were then subjected to 30 min ischemia through ligation of the left anterior descending coronary artery, followed by 3 h reperfusion through release of the ligation. The hearts were harvested and cut into four slices. To assess infarct size (IS), an index representing heart damage, the slices were stained with 2,3,5-triphenyltetrazolium chloride (TTC). To elucidate underlying mechanisms, Western blotting was performed for the slices. RESULTS: Supplementation with 10 or 100 mg/kg/d of PSH significantly reduces the IS. PSH supplementation (100 mg/kg/d) tends to reduce caspase-3 generation and increase BCL-2/BAX ratio. PSH supplementation also upregulates the expression of nuclear factor erythroid 2-related factor 2 (NRF2), and its target genes including antioxidant enzymes such as glutathione S-transferase mu 2 (GSTM2) and superoxide dismutase 2 (SOD2). PSH supplementation upregulates some sirtuins ($NAD^+$-dependent deacetylases) including SIRT5 (a mitochondrial sirtuin) and SIRT6 and SIRT7 (nuclear sirtuins). Finally, PSH supplementation upregulates the expression of protein kinase A (PKA), and increases phosphorylated cAMP response element-binding protein (CREB) (pCREB), a target protein of PKA. CONCLUSIONS: The results from this study indicate that PSH consumption reduces myocardial I/R injury in rats by inhibiting the apoptotic cascades through modulation of gene expression of several genes located upstream of apoptosis. Therefore, we believe that PSH can be developed as a functional food that would be beneficial in the prevention of MI.

• The Journal of Korean Medicine
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• v.40 no.3
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• pp.35-58
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• 2019

Objectives: The aim of this study was to investigate the anti-inflammatory effects of Curcuma longa rhizoma extract in an experimental rat model of osteoarthritis. Methods: Osteoarthritis was induced in rats by injecting monosodium iodoacetate (MIA) into the knee joint cavity of rats. The rats were divided into 5 groups (Normal, Control, positive comparison, low (CL) and high (CH) concentration groups). Rats in the low concentration (CL) group had MIA-induced osteoarthritis; they were treated with Curcuma longa rhizoma extract at a dose of 50mg/kg body weight. Rats in the high concentration (CH) group had MIA-induced osteoarthritis; they were treated with Curcuma longa rhizoma extract at a dose of 100mg/kg body weight. Hind paw weight distribution and ROS levels were measured. At the end of all treatments, changes in alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine levels were analyzed. In addition, inflammatory protein levels were evaluated by western blot analysis. Results: In this study, hind paw weight distribution significantly improved in the CL and CH groups, while. Reactive oxygen species (ROS) production significantly decreased in both. The levels of ALT, AST, BUN, and creatinine did not significantly change in either group. The production of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4), $p47^{phox}$, and Ras-related C3 botulinum toxin substrate 1 (RAC1) decreased in both. Catalase, heme oxygenase-1 (HO-1) and superoxide dismutase (SOD) significantly increased in the CL and CH groups, respectively. Nuclear factor erythroid 2 (Nrf2) increased, but there were no significant differences between the experimental and control groups. Inflammatory cytokines, including nuclear factor-kappa Bp65 (NF-${\kappa}Bp65$), interleukin-1beta (IL-$1{\beta}$), and tumor necrosis factor-alpha (TNF-${\alpha}$), decreased significantly in both the CL and CH groups. Conclusions: Our results showed that Curcuma longa rhizoma extract has anti-inflammatory effects. Anti-inflammatory activity is regulated by the inhibition of inflammatory cytokines and mediators, such as NF-${\kappa}B$, therefore, it suppresses cartilage damage as well.

• The Journal of Korean Obstetrics and Gynecology
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• v.35 no.3
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• pp.1-23
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• 2022

Objectives: The purpose of this study is to evaluate anti-breast cancer and anti-inflammatory effects of Chungganhaewool-tang and Shipyeukmiyeugi-eum. Methods: MDA-MB-231 cells were used to measure cytotoxicity, Reactive oxygen species (ROS) production, protein expression amounts of Bcl-2-associated X protein (Bax), B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xl), Cytochrome C Caspase-3, Caspase-7, Caspase-9, Poly ADP-ribose polymerase (PARP), Nuclear factor erythroid-2-related factor 2 (Nrf2), Heme oxygenase-1 (HO-1) and NAD (P) H Quinone Oxidoreductase 1 (NQO1) to evaluate the anti-breast cancer effects of Chungganhaewool-tang (CHT) and Shipyeukmiyeugi-eum (SYE), and THP-1 cells, differentiated into macrophage and induced inflammation with Lipopolysaccharide (LPS), were used to measure production amounts of ROS, Nitric oxide (NO), and protein expression amounts of Inducible nitric oxide synthase (iNOS), Cyclooxygenase (COX-2), Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6) and Tumor necrosis factor-alpha (TNF-α) to evaluate the anti-inflammatory effects of CHT and SYE. Results: CHT and SYE reduced MDA-MB-231 cell counts, increased protein expression of Bax and Cytochrome C, and decreased protein expression of Bcl-2, Bcl-xl. The protein expression amounts of Caspase-3, 7, and 9 decreased, but amounts of the active form, cleaved Caspase-3, 7, and 9, increased. In addition, PARP protein expression decreased, the amount of PARP protein in the cleaved form increased, and the amount of protein expressions of Nrf2 and HO-1 decreased, but NQO1 showed no significant difference. In THP-1 cells CHT and SYE reduced ROS and NO, and reduced protein expressions of iNOS, COX-2, IL-1, and TNF-α, but only SYE groups reduced IL-6. Conclusions: This study suggests that CHT and SYE have potential to be used as treatments for breast cancer.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.277-286
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• 2016

Makgeolli lees (ML) has several physiological effects such as antioxidant, antidiabetic, and anticancer properties, but its biological functions have not been determined definitively. Here, we tested whether ML has a cytoprotective effect on paraquat (PQ)-induced oxidative stress in the human lung carcinoma cell line A549. At 0.1 mg/ml ML, viability of PQ-exposed A549 cells was restored by 12.4%, 18.5%, and 48.6% after 24, 48, and 72 h, respectively. ML also reduced production of the intracellular reactive oxygen species (ROS) that were generated by PQ treatment. Further experiments revealed that ML treatment enhanced the expression and nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2) as well as ARE-GFP reporter activity. ML treatment also effectively increased the expression of NRF2's target genes NAD(P)H dehydrogenase quinone 1 (NQO1) and heme oxygenase 1 (HO-1). Moreover, we found that expression of cytoprotective genes, including glutathione peroxidases (GPXs), superoxide dismutase (SOD1), catalase (CAT), peroxiredoxin 3 (PRDX3), and peroxiredoxin 4 (PRDX4), was greatly enhanced by treatment with ML during PQ exposure. Taken together, the data suggest that treatment of PQ-exposed A549 cells with ML ameliorates cytotoxicity through induction of NRF2 expression and its target genes HO-1, NQO1, and other antioxidant genes. Thus, ML may serve as a functional food applicable to ROS-mediated human diseases.

• Journal of Ginseng Research
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• v.45 no.3
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• pp.408-419
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• 2021

Background: The decreased renal function is known to be associated with biological aging, of which the main pathological features are chronic inflammation and renal interstitial fibrosis. In previous studies, we reported that total saponins from Panax japonicus (SPJs) can availably protect acute myocardial ischemia. We proposed that SPJs might have similar protective effects for aging-associated renal interstitial fibrosis. Thus, in the present study, we evaluated the overall effect of SPJs on renal fibrosis. Methods: Sprague-Dawley (SD) aging rats were given SPJs by gavage beginning from 18 months old, at 10 mg/kg/d and 60 mg/kg/d, up to 24 months old. After the experiment, changes in morphology, function and fibrosis of their kidneys were detected. The levels of serum uric acid (UA), β2-microglobulin (β2-MG) and cystatin C (Cys C) were assayed with ELISA kits. The levels of extracellular matrix (ECM), matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), inflammatory factors and changes of oxidative stress parameters were examined. Results: After SPJs treatment, SD rats showed significantly histopathological changes in kidneys accompanied by decreased renal fibrosis and increased renal function; As compared with those in 3-month group, the levels of serum UA, Cys C and β2-MG in 24-month group were significantly increased (p < 0.05). Compared with those in the 24-month group, the levels of serum UA, Cys C and β2-MG in the SPJ-H group were significantly decreased. While ECM was reduced and the levels of MMP-2 and MMP-9 were increased, the levels of TIMP-1, TIMP-2 and transforming growth factor-β1 (TGF-β1)/Smad signaling were decreased; the expression level of phosphorylated nuclear factor kappa-B (NF-κB) was down-regulated with reduced inflammatory factors; meanwhile, the expression of nuclear factor erythroid 2-related factor 2-antioxidant response element (Nrf2-ARE) signaling was aggrandized. Conclusion: These results suggest that SPJs treatment can improve age-associated renal fibrosis by inhibiting TGF-β1/Smad, NFκB signaling pathways and activating Nrf2-ARE signaling pathways and that SPJs can be a potentially valuable anti-renal fibrosis drug.

• Molecules and Cells
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• v.27 no.3
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• pp.279-282
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• 2009

"Two-cysteine" peroxiredoxins are antioxidant enzymes that exert a cytoprotective effect in many models of oxidative stress. However, under highly oxidizing conditions they can be inactivated through hyperoxidation of their peroxidatic active site cysteine residue. Sulfiredoxin can reverse this hyperoxidation, thus reactivating peroxiredoxins. Here we review recent investigations that have shed further light on sulfiredoxin's role and regulation. Studies have revealed sulfiredoxin to be a dynamically regulated gene whose transcription is induced by a variety of signals and stimuli. Sulfiredoxin expression is regulated by the transcription factor AP-1, which mediates its up-regulation by synaptic activity in neurons, resulting in protection against oxidative stress. Furthermore, sulfiredoxin has been identified as a new member of the family of genes regulated by Nuclear factor erythroid 2-related factor (Nrf2) via a conserved cis-acting antioxidant response element (ARE). As such, sulfiredoxin is likely to contribute to the net antioxidative effect of small molecule activators of Nrf2. As discussed here, the proximal AP-1 site of the sulfiredoxin promoter is embedded within the ARE, as is common with Nrf2 target genes. Other recent studies have shown that sulfiredoxin induction via Nrf2 may form an important part of the protective response to oxidative stress in the lung, preventing peroxiredoxin hyperoxidation and, in certain cases, subsequent degradation. We illustrate here that sulfiredoxin can be rapidly induced in vivo by administration of CDDO-TFEA, a synthetic triterpenoid inducer of endogenous Nrf2, which may offer a way of reversing peroxiredoxin hyperoxidation in vivo following chronic or acute oxidative stress.