scholarly journals Baicalein Alleviates Liver Oxidative Stress and Apoptosis Induced by High-Level Glucose through the Activation of the PERK/Nrf2 Signaling Pathway

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 599
Author(s):  
Yuesheng Dong ◽  
Yan Xing ◽  
Jin Sun ◽  
Wenlong Sun ◽  
Yongbin Xu ◽  
...  

Baicalein, a widely-distributed natural flavonoid, exhibits antioxidative activity in mice with type-2 diabetes. However, the underlying mechanisms remain partially elucidated. In this study, we investigated the effect of baicalein on protein kinase R-like ER kinase (PERK)/nuclear factor erythroid-2-related factor 2 (Nrf2) pathway for the alleviation of oxidative stress and apoptosis. Human liver HL-7702 cells were stimulated with 60.5 mM of glucose to induce oxidative stress and treated with baicalein. The apoptosis was determined by fluorescence microscopy and flow cytometry. The regulation of the PERK/Nrf2 pathway by baicalein was determined by immunoblotting in both HL-7702 cells and liver tissues from diabetic mice. We found that baicalein significantly alleviated the oxidative stress and apoptosis in HL-7702 cells stimulated with glucose. Mechanistic studies showed that baicalein downregulated PERK and upregulated Nrf2, two key proteins involved in endoplasmic reticulum stress, in both HL-7702 cells and liver tissues from diabetic mice receiving baicalein treatment. Furthermore, the subcellular localization of Nrf2 and the regulation of downstream proteins including heme oxygenase-1 and CCAAT-enhancer-binding protein homologous protein (CHOP) by baicalein were also investigated. Our results suggest that the regulation of the PERK/Nrf2 pathway is one of the mechanisms contributing to the bioactivities of baicalein to improve diabetes-associated complications.

2020 ◽  
Vol 33 (7) ◽  
pp. 610-619 ◽  
Author(s):  
Peijian Wang ◽  
Yi Yang ◽  
Dan Wang ◽  
Qiyuan Yang ◽  
Jindong Wan ◽  
...  

Abstract BACKGROUND Oxidative stress is known to be associated with the development of diabetes. Cinnamaldehyde (CA) is a spice compound in cinnamon that enhances the antioxidant defense against reactive oxygen species (ROS) by activating nuclear factor erythroid-related factor 2 (Nrf2), which has been shown to have a cardioprotection effect. However, the relationship between CA and Nrf2 in diabetic vascular complications remains unclear. METHODS Leptin receptor-deficient (db/db) mice were fed normal chow or diet containing 0.02% CA for 12 weeks. The vascular tone, blood pressure, superoxide level, nitric oxide (NO) production, renal morphology, and function were measured in each group. RESULTS CA remarkably inhibited ROS generation, preserved NO production, increased phosphorylated endothelial nitric oxide synthase (p-eNOS), attenuated the upregulation of nitrotyrosine, P22 and P47 in aortas of db/db mice, and apparently ameliorated the elevation of type IV collagen, TGF-β1, P22, and P47 in kidney of db/db mice. Feeding with CA improved endothelium-dependent relaxation of aortas and mesenteric arteries, and alleviated the remodeling of mesenteric arteries in db/db mice. Additionally, dietary CA ameliorated glomerular fibrosis and renal dysfunction in diabetic mice. Nrf2 and its targeted genes heme oxygenase-1 (HO-1) and quinone oxidoreductase-1 (NQO-1) were slightly increased in db/db mice and further upregulated by CA. However, these protective effects of CA were reversed in Nrf2 downregulation mice. CONCLUSIONS A prolonged diet of CA protects against diabetic vascular dysfunction by inhibiting oxidative stress through activating of Nrf2 signaling pathway in db/db mice.


2018 ◽  
Vol 38 (2) ◽  
pp. 247-254 ◽  
Author(s):  
WX Zhang ◽  
XY Xiao ◽  
CG Peng ◽  
WL Chen ◽  
S Xie ◽  
...  

Objective: To investigate the therapeutic effect and mechanism of sodium tanshinone IIA sulfate (STS) on paraquat (PQ)-induced myocardial injuries in a rat model. Methods: Healthy adult Sprague Dawley rats were randomly divided into normal control, PQ, and PQ + STS groups. PQ group was given a single intragastric administration of PQ (80 mg/kg). PQ + STS group was intraperitoneally injected with STS (1 ml/kg) at 30 min following PQ exposure. Rats in control and PQ groups were injected with equal amount of saline. After 12, 24, 48, and 72 h, rats were killed, and the apoptosis of myocardial cells was detected. Myocardial expression of Bax and Bcl-2 was measured. The activity of the nuclear erythroid 2-related factor 2 (Nrf2) pathway was assessed by Western blot. Results: The apoptotic cells in PQ group were significantly increased in a time-dependent manner compared with the control group ( p < 0.01). The rats in PQ group exhibited significantly lower Bcl-2 expression, but notably higher Bax expression at 12, 24, 48, and 72 h after PQ exposure ( p < 0.05 or 0.01). STS intervention markedly reduced the proportion of apoptotic myocardial cells, increased Bcl-2 expression, and decreased Bax expression at 24, 48, and 72 h after treatment ( p < 0.05 or 0.01). The expression of phosphorylated Nrf2 and heme oxygenase 1 in PQ + STS group was significantly increased compared with PQ and control groups ( p < 0.05 or 0.01). Conclusion: STS effectively inhibits PQ-induced myocardial cell apoptosis in rats via modulating the Nrf2 pathway, suggesting its potential as a promising therapeutic agent for PQ-induced myocardium damage.


Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 380 ◽  
Author(s):  
Huang ◽  
Chang ◽  
Chau ◽  
Chiu

Hispidin, a polyphenol compound isolated from Phellinus linteus, has been reported to possess antioxidant activities. In this study, we aimed to investigate the mechanisms underlying the protective effect of hispidin against hydrogen peroxide (H2O2)-induced oxidative stress on Adult Retinal Pigment Epithelial cell line-19 (ARPE-19) cells. Hispidin was not cytotoxic to ARPE-19 cells at concentrations of less than 50 μM. The levels of intracellular reactive oxygen species (ROS) were analyzed by dichlorofluorescin diacetate (DCFDA) staining. Hispidin significantly restored H2O2-induced cell death and reduced the levels of intracellular ROS. The expression levels of antioxidant enzymes, such as NAD(P)H:Quinine oxidoreductase-1 (NQO-1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM) were examined using real-time PCR and Western blotting. Our results showed that hispidin markedly enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), HO-1, NQO-1, GCLM, and GCLC in a dose-dependent manner. Furthermore, knockdown experiments revealed that transfection with Nrf2 siRNA successfully suppresses the hispidin activated Nrf2 signaling in ARPE-19 cells. Moreover, activation of the c-Jun N-terminal kinase (JNK) pathway is involved in mediating the protective effects of hispidin on the ARPE-19 cells. Thus, the present study demonstrated that hispidin provides protection against H2O2-induced damage in ARPE-19 cells via activation of Nrf2 signaling and up-regulation of its downstream targets, including Phase II enzymes, which might be associated with the activation of the JNK pathway.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jiayi Chen ◽  
Fangting He ◽  
Sijing Liu ◽  
Tao Zhou ◽  
Saira Baloch ◽  
...  

Ligustrum robustum is a traditional herbal tea that is widely distributed in southwest China. The health effects of L. robustum are characteristics of clearing heat, antioxidant, inducing resurgence, and improving digestion. However, the molecular mechanisms related to these effects, particularly the antioxidant mechanism, have been seldom reported. The objective of this study was to assess antioxidative capacity of L. robustum, and its protective effects and mechanisms against hydrogen peroxide (H2O2) - induced toxicity in Caco-2 cells. Total phenolic contents, free radical scavenging activity, and reducing capacity of L. robustum were measured. The effects of L. robustum on the cell viability and antioxidant defense system were explored. The expression of nuclear factor E2 related factor 2 (Nrf2) and antioxidant genes: quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and glutamate cysteine ligase (GCL) were analyzed by western blot and qPCR. Pretreatment of L. robustum could significantly reduce H2O2-induced toxicity, decrease the level of reactive oxygen species (ROS) and malondialdehyde (MDA), and increase the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GR). By activating the expression of Nrf2 and antioxidant genes (NQO1, HO-1, and GCL), L. robustum exerts cytoprotective effect in Caco-2 cells dealt with H2O2. Therefore, the well-established model of Caco-2 cells demonstrates that L. robustum may modulate the cytoprotective effect against the H2O2-induced oxidative stress through the Nrf2 signaling pathway.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Dingfu Xiao ◽  
Daixiu Yuan ◽  
Bihui Tan ◽  
Jing Wang ◽  
Yanhong Liu ◽  
...  

Eucommia ulmoides flavones (EUF) have been demonstrated to alleviate oxidative stress and intestinal damage in piglets, but their effect target is still poorly understood. NF-E2-related factor 2 (Nrf2) pathway plays a very important role in the defense mechanism. This study was designed to investigate the regulation of EUF on the Nrf2 pathway and inhibition of Nrf2 on oxidative stress in the intestine of piglets. An in vivo study was conducted in weaned piglets treated with basal diet, basal diet+diquat, and 100 mg/kg EUF diet+diquat for 14 d to determine Nrf2 and Keap1 protein expressions, as well as downstream antioxidant gene mRNA expression. An in vitro study was performed in a porcine jejunal epithelial cell line to investigate the effect of inhibiting Nrf2 on cell growth and intracellular oxidative stress parameters. The results showed that the supplementation of EUF decreased the oxidized glutathione (GSSG) concentration and the ratio of GSSG to glutathione (GSH) but increased the protein expressions of nuclear Nrf2 and Kelch-like ECH-associated protein 1 (Keap1) as well as mRNA expression of heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1), and glutamate cysteine ligase catalytic subunit (GCLC) in the small intestinal mucosa of diquat-challenged piglets. When Nrf2 was inhibited by using ML385, cell viability, cellular antioxidant activities, expressions of nuclear Nrf2 and Keap1 protein, and downstream antioxidant enzyme (HO-1, NQO-1, and GCLC) mRNA were decreased in paraquat-treated enterocytes. These results showed that the Nrf2 signaling pathway played an important role in EUF-regulating oxidative stress in the intestine of piglets.


2020 ◽  
Vol 15 (8) ◽  
pp. 1934578X2094723
Author(s):  
Pan Chen ◽  
Ziting Xiao ◽  
Hao Wu ◽  
Yonggang Wang ◽  
Weiwei Su ◽  
...  

Naringin possesses strong antioxidative activity and can protect against some respiratory diseases. Oxidative stress is thought to be a major factor in the development of many tobacco-caused diseases. The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a critical role in the regulation of oxidative stress. The dynamic changes in the antioxidant system in the lung that are induced by cigarette smoke (CS) are not well investigated, and how naringin affects these changes remains unknown. This study aimed to investigate the dynamic changes between the oxidation and antioxidant systems resulting from CS exposure and the effects of naringin on these changes in mice. Mice were chronically exposed to CS for 30 days. The levels of malondialdehyde (MDA), glutathione (GSH), interleukin (IL)-6, and tumor necrosis factor-alpha (TNF-α); the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px); and the expressions of Nrf2, heme oxygenase-1 (HO-1), and nicotinamide adenine dinucleotide phosphate quinone dehydrogenase 1 (NQO1) in lung tissue were measured on days 2, 7, and 30. The levels of MDA, GSH, IL-6, and TNF-α in the lung were found to increase throughout the exposure. SOD and GSH-Px activities showed an increase on day 2 and a decrease on days 7 and 30. The messenger ribonucleic acid expressions of Nrf2, HO-1, and NQO1 were elevated on day 2 and decreased on day 7; Nrf2 and HO-1 expressions were continually decreased, but NQO1 expression was increased again, on day 30. Naringin restored the levels of these biochemical indices to normal throughout the experiment, suggesting that naringin protected against the CS-induced oxidative damage by suppressing the increase of antioxidants resulting from the early stage of CS exposure, as well as inhibiting the depletion of antioxidants due to long-term oxidative stress. Naringin also suppressed lung inflammation by inhibiting IL-6 and TNF-α. These results indicate that naringin possesses a powerful ability to maintain the balance of the oxidation/antioxidant system in the lung when subjected to CS exposure, probably by regulating the Nrf2 signaling pathway.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Golbarg Rahimi ◽  
Salime Heydari ◽  
Bahareh Rahimi ◽  
Navid Abedpoor ◽  
Iman Niktab ◽  
...  

Abstract Background SPTC is a mix of four herbal components (Salvia officinalis, Panax ginseng, Trigonella foenum-graeceum, and Cinnamomum zeylanicum) which might be prevented the development of AGE rich diet-induced diabetic complication and liver injury through activated the nuclear factor erythroid-2-related-factor-2 (Nrf2) pathway. Nrf2, as a master regulator of antioxidant response elements by activating cytoprotective genes expression, is decreased oxidative stress that associated with hyperglycemia and increases insulin sensitivity. the aim of this study was to assess whether the combination therapy of SPTC along with exercise or metformin moderate oxidative stress related liver injurie with more favorable effects in the treatment of AGE rich diet-induced type 2 diabetic mice. Methods We induced diabetes in C57BL/6 mice by AGE using a diet supplementation and limitation of physical activity. After 16 weeks of intervention, AGE fed mice were compared to control mice. Diabetic mice were assigned into seven experimental groups (each group; n = 5): diabetic mice, diabetic mice treated with SPTC (130 mg/kg), diabetic mice treated with Salvia Officinalis (65 mg/kg), diabetic mice treated with metformin (300 mg/kg), diabetic mice with endurance exercise training, diabetic mice treated with SPTC + metformin (130/300 mg/kg), diabetic mice treated with SPTC + exercise training. Results SPTC + exercise and SPTC + metformin reduced diabetic complications like gain weight, water and calorie intake, blood glucose, insulin, and GLUT4 content more efficiently than each treatment. These combinations improved oxidative stress hemostasis by activating the Nrf2 signaling pathway and attenuating keap1 protein more significantly. Conclusion Eventually, combined treatment of SPTC with exercise or metformin as a novel approach had more beneficial effects to prevent the development of diabetes and oxidative stress associated with hyperglycemia.


Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 496 ◽  
Author(s):  
Yawang Sun ◽  
Yongjiang Wu ◽  
Zili Wang ◽  
Juncai Chen ◽  
You Yang ◽  
...  

In practical dairy production, cows are frequently subjected to inflammatory diseases, such as high-grain diet-induced subacute ruminal acidosis (SARA) as well as mastitis and metritis. Under the circumstances, lipopolysaccharide (LPS) induces oxidative stress within the cow and in the mammary epithelial cells. It has implications in practical production to alleviate oxidative stress and to optimize the lactational function of the mammary epithelial cells. This study thus aimed to investigate the antioxidative effects of dandelion aqueous extract (DAE) on LPS-induced oxidative stress and the mechanism of DAE as an antioxidant to alleviate oxidative stress through the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the bovine mammary epithelial cell line MAC-T cells. The cells were cultured for 48 h in six treatments including control (without LPS and DAE), LPS (100 ng/mL), DAE10 (100 ng/mL LPS and 10 μg/mL DAE), DAE50 (100 ng/mL LPS and 50 μg/mL DAE), DAE100 (100 ng/mL LPS and 100 μg/mL DAE), and DAE200 (100 ng/mL LPS and 200 μg/mL DAE), respectively. The results showed that cell viability was reduced by LPS, and the adverse effect of LPS was suppressed with the supplementation of DAE. Lipopolysaccharide-induced oxidative stress through enhancing reactive oxygen species (ROS) production, resulted in increases in oxidative damage marker concentrations, while 10 and 50 μg/mL DAE alleviated the LPS-induced oxidative stress via scavenging cellular ROS and improving antioxidant enzyme activity. The upregulation of antioxidative gene expression in DAE treatments was promoted through activating the Nrf2 signaling pathway, with DAE at a concentration of 50 μg/mL exhibiting the highest effect. Overall, DAE acted as an effective antioxidant to inhibit LPS-induced oxidative stress and as a potential inducer of the Nrf2 signaling pathway.


2021 ◽  
Author(s):  
Rui Ji ◽  
Fang-yuan Jia ◽  
Xin Chen ◽  
Ze-hao Wang ◽  
Wen-yi Jin ◽  
...  

Abstract Background: In the past few years, emerging evidence established persistent oxidative stress to be a key player in the pathogenesis of polycystic ovary syndrome (PCOS). Particularly, it damages the function of granulosa cells, and thus hinders the development of follicles. The present study aimed to explore and establish the protective effects of salidroside on dihydrotestosterone (DHT)‐induced Granulosa‐like tumor cell line (KGN), mediated via antioxidant mechanisms.Methods: KGN cells were treated with DHT as a PCOS cell model, and then incubated with salidroside in different concentrations. Apoptosis and reactive oxygen species (ROS) accumulation were assessed by flow cytometry, mitochondrial membrane potential depolarization and the nuclear translocation of Nrf2 were detected by immunofluorescence staining, and the level of apoptosis-related proteins and antioxidant proteins was assessed by western blotting.Results: Salidroside partly reversed DHT mediated effects, via stimulation of nuclear factor erythroid 2‐related factor 2 (Nrf2) signaling pathway and the downstream antioxidant proteins heme oxygenase‐1(HO‐1) and quinine oxidoreductase 1(NQO1). Additionally, knockdown of Nrf2 resulted in a deterioration in DHT‐induced oxidative stress and apoptosis. It partly moderated the protective effects of salidroside as well. Mechanistically, AMPK was identified to be the upstream signaling involved in salidroside‐induced Nrf2 activation, as silencing of AMPK partly prevented the upregulation of Nrf2 and the downstream proteins HO‐1 and NQO1. Conclusion: The present study is the first to effectively demonstrate the inhibitory effect of salidroside on DHT‐stimulated oxidative stress and apoptosis in KGN cells, which was dependent on Nrf2 activation that involved AMPK.


2020 ◽  
pp. 074823372097942
Author(s):  
Guangtao Yang ◽  
Yingping Xiang ◽  
Wei Zhou ◽  
Xiaohuan Zhong ◽  
Yanfang Zhang ◽  
...  

The bromoalkane, 1-bromopropane (1-BP), may damage the reproductive system though oxidative stress, while the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) plays an important role in regulating intracellular antioxidant levels against oxidative stress. This study explored the role of oxidative stress and the Nrf2 signaling pathway in mediating the reproductive toxicity of 1-BP using the ovarian carcinoma cell line OVCAR-3 as an in vitro model of the human ovary. OVCAR-3 cells were treated with 1, 5, 10 and 15 mM 1-BP. After 24 h, the cellular reactive oxygen species and malondialdehyde concentrations significantly increased, while the superoxide dismutase activity decreased; translocation of Nrf2 from the cytosol to the nucleus as well as downstream protein expression of Nrf2-regulated genes heme oxygenase-1 and Bcl-2 was inhibited. Apoptosis was also observed, accompanied by increased caspase-3 and caspase-9 activity. The antioxidant vitamin C alleviated 1-BP-induced apoptosis by inhibiting caspase activity activating the Nrf2 signaling pathway. These findings suggested that 1-BP induced oxidative stress and apoptosis in OVCAR-3 cells through inactivation of Nrf2 signaling.


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