scholarly journals Gentiopicroside Ameliorates Oxidative Stress and Lipid Accumulation through Nuclear Factor Erythroid 2-Related Factor 2 Activation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Meiyu Jin ◽  
Haihua Feng ◽  
Yue Wang ◽  
Siru Yan ◽  
Bingyu Shen ◽  
...  

The activation of nuclear factor erythroid 2-related factor 2 (Nrf2) is closely related to the alleviation of nonalcoholic fatty liver disease (NAFLD) by regulating oxidative stress and lipid homeostasis. Gentiopicroside (GPS), an iridoid glycoside found in the Gentianaceae, possesses anti-inflammatory and antioxidant effects. However, the protective effects of GPS on lipid accumulation and oxidative damage have not been investigated thoroughly in free fatty acid- (FFA-) induced HepG2 cells and tyloxapol- (Ty-) induced hyperlipidemia mice. Cell counting kit-8 assays, Oil Red O staining, Western blotting analysis, extraction of nuclear and cytosolic proteins, and biochemical index assay were employed to explore the mechanisms by which GPS exerts a protective effect on FFA-induced HepG2 cells and Ty-induced hyperlipidemia mouse model. This paper demonstrates that GPS could effectively alleviate NAFLD by elevating cell viability, reducing fatty deposition, downregulating TG, and activating nucleus Nrf2 in FFA-induced HepG2 cells. Meanwhile, GPS significantly regulated the activation of phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway, Nrf2 antioxidant pathway, peroxisome proliferator-activated receptor α (PPARα), and GPS-inhibited sterol regulatory element-binding protein-1c (SREBP-1c) expression in FFA-stimulated lipid accumulation of HepG2 cells and Ty-treated mice. Interestingly, we highlight that PI3K/AKT inhibitor (LY294002) markedly increased the expression of Nrf2 antioxidant pathway, PPARα, and downregulated SREBP-1c in FFA-stimulated HepG2 cells. For these reasons, we found that the deletion of Nrf2 could lose the protective effects of GPS on the Nrf2 antioxidant pathway and PPARα activation and SREBP-1c inactivation in FFA-stimulated HepG2 cells and Ty-treated mice. GPS treatment had no effect on abnormal lipogenesis and antioxidant enzymes in Ty-induced Nrf2-/- mice. This work gives a new explanation that GPS may be a useful therapeutic strategy for NAFLD through upregulation of the Nrf2 antioxidant pathway, which can alleviate oxidative damage and lipid accumulation.

2018 ◽  
Vol 46 (02) ◽  
pp. 469-488 ◽  
Author(s):  
Ji Yun Jung ◽  
Sang Mi Park ◽  
Hae Li Ko ◽  
Jong Rok Lee ◽  
Chung A Park ◽  
...  

Oxidative stress induced by reactive oxygen species is the main cause of various liver diseases. This study investigated the hepatoprotective effect of Epimedium koreanum Nakai water extract (EKE) against arachidonic acid (AA)[Formula: see text][Formula: see text][Formula: see text]iron-mediated cytotoxicity in HepG2 cells and carbon tetrachloride (CCl4-)-mediated acute liver injury in mice. Pretreatment with EKE (30 and 100[Formula: see text][Formula: see text]g/mL) significantly inhibited AA[Formula: see text][Formula: see text][Formula: see text]iron-mediated cytotoxicity in HepG2 cells by preventing changes in the expression of cleaved caspase-3 and poly(ADP-ribose) polymerase. EKE attenuated hydrogen peroxide production, glutathione depletion, and mitochondrial membrane dysfunction. EKE also increased the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2), transactivated anti-oxidant response element harboring luciferase activity, and induced the expression of anti-oxidant genes. Furthermore, the cytoprotective effect of EKE against AA[Formula: see text][Formula: see text][Formula: see text]iron was blocked in Nrf2 knockout cells. Ultra-performance liquid chromatography analysis showed that EKE contained icariin, icaritin, and quercetin; icaritin and quercetin were both found to protect HepG2 cells from AA[Formula: see text][Formula: see text][Formula: see text]iron via Nrf2 activation. In a CCl4-induced mouse model of liver injury, pretreatment with EKE (300[Formula: see text]mg/kg) for four consecutive days ameliorated CCl4-mediated increases in serum aspartate aminotransferase activity, histological activity index, hepatic parenchyma degeneration, and inflammatory cell infiltration. EKE also decreased the number of nitrotyrosine-, 4-hydroxynonenal-, cleaved caspase-3-, and cleaved poly(ADP-ribose) polymerase-positive cells in hepatic tissues. These results suggest EKE is a promising candidate for the prevention or treatment of oxidative stress-related liver diseases via Nrf2 activation.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Chitra Basu ◽  
Runa Sur

Hydrogen peroxide (H2O2) mediated oxidative stress leading to hepatocyte apoptosis plays a pivotal role in the pathophysiology of several chronic liver diseases. This study demonstrates that S-allyl cysteine (SAC) renders cytoprotective effects on H2O2 induced oxidative damage and apoptosis in HepG2 cells. Cell viability assay showed that SAC protected HepG2 cells from H2O2 induced cytotoxicity. Further, SAC treatment dose dependently inhibited H2O2 induced apoptosis via decreasing the Bax/Bcl-2 ratio, restoring mitochondrial membrane potential (∆Ψm), inhibiting mitochondrial cytochrome c release, and inhibiting proteolytic cleavage of caspase-3. SAC protected cells from H2O2 induced oxidative damage by inhibiting reactive oxygen species accumulation and lipid peroxidation. The mechanism underlying the antiapoptotic and antioxidative role of SAC is the induction of the heme oxygenase-1 (HO-1) gene in an NF-E2-related factor-2 (Nrf-2) and Akt dependent manner. Specifically SAC was found to induce the phosphorylation of Akt and enhance the nuclear localization of Nrf-2 in cells. Our results were further confirmed by specific HO-1 gene knockdown studies which clearly demonstrated that HO-1 induction indeed played a key role in SAC mediated inhibition of apoptosis and ROS production in HepG2 cells, thus suggesting a hepatoprotective role of SAC in combating oxidative stress mediated liver diseases.


Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1314
Author(s):  
Seung-Cheol Lee ◽  
Seung-Cheol Jee ◽  
Min Kim ◽  
Soee Kim ◽  
Min Kyoung Shin ◽  
...  

Benzo[a]pyrene (B[a]P) is a potentially hepatotoxic group-1 carcinogen taken up by the body through ingestion of daily foods. B[a]P is widely known to cause DNA and protein damages, which are closely related to cell transformation. Accordingly, studies on natural bioactive compounds that attenuate such chemical-induced toxicities have significant impacts on public health. This study aimed to uncover the mechanism of curcumin, the major curcuminoid in turmeric (Curcuma longa), in modulating the lipid accumulation and oxidative stress mediated by B[a]P cytotoxicity in HepG2 cells. Curcumin treatment reduced the B[a]P-induced lipid accumulation and reactive oxygen spicies (ROS) upregulation and recovered the cell viability. Cytochrome P450 family 1 subfamily A polypeptide 1 (CYP1A1) and Cytochrome P450 subfamily B polypeptide 1 (CYP1B1) downregulation resulting from decreased aryl hydrocarbon receptor (AhR) translocation into nuclei attenuated the effects of B[a]P-induced lipid accumulation and repressed cell viability, respectively. Moreover, the curcumin-induced reduction in ROS generation decreased the nuclear translocation of Nuclear factor erythroid-2-related factor 2 (Nrf2) and the expression of phase-II detoxifying enzymes. These results indicate that curcumin suppresses B[a]P-induced lipid accumulation and ROS generation which can potentially induce nonalcoholic fatty liver disease (NAFLD) and can shed a light on the detoxifying effect of curcumin.


2020 ◽  
Vol 148 ◽  
pp. 112-121 ◽  
Author(s):  
Jin Feng ◽  
Yuxuan He ◽  
Yulong Shen ◽  
Guanglin Zhang ◽  
Shaotao Ma ◽  
...  

Nutrients ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 382 ◽  
Author(s):  
Hwa-Young Lee ◽  
Geum-Hwa Lee ◽  
Young Yoon ◽  
Han-Jung Chae

This study aimed to characterize the protective effects of R. verniciflua extract (ILF-R) and E. ulmoides extract (ILF-E), the combination called ILF-RE, against chronic CCl4-induced liver oxidative injury in rats, as well as to investigate the mechanism underlying hepatoprotection by ILF-RE against CCl4-induced hepatic dysfunction. Chronic hepatic stress was induced via intraperitoneal (IP) administration of a mixture of CCl4 (0.2 mL/100 g body weight) and olive oil [1:1(v/v)] twice a week for 4 weeks to rats. ILF-RE was administered orally at 40, 80, and 120 mg/kg to rats for 4 weeks. Alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transpeptidase (GGT), and lipid peroxidation assays were performed, and total triglyceride, cholesterol, and LDL-cholesterol levels were quantified. Furthermore, ER stress and lipogenesis-related gene expression including sterol regulatory element-binding transcription factor 1 (SREBP-1), fatty acid synthase (FAS), and P-AMPK were assessed. ILF-RE markedly protected against liver damage by inhibiting oxidative stress and increasing antioxidant enzyme activity including glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase. Furthermore, hepatic dyslipidemia was regulated after ILF-RE administration. Moreover, hepatic lipid accumulation and its associated lipogenic genes, including those encoding SREBP-1 and FAS, were regulated after ILF-RE administration. This was accompanied by regulation of ER stress response signaling, suggesting a mechanism underlying ILF-RE-mediated hepatoprotection against lipid accumulation. The present results indicate that ILF-RE exerts hepatoprotective effects against chronic CCl4-induced dysfunction by suppressing hepatic oxidative stress and lipogenesis, suggesting that ILF-RE is a potential preventive/therapeutic natural product in treating hepatoxicity and associated dysfunction.


Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 464
Author(s):  
Alessio Filippo Peritore ◽  
Ramona D’Amico ◽  
Marika Cordaro ◽  
Rosalba Siracusa ◽  
Roberta Fusco ◽  
...  

Palmitoylethanolamide (PEA) has well-known anti-inflammatory effects. However, PEA does not possess an antioxidant ability. A comicronized formulation of ultramicronized PEA (um-PEA) and polydatin (Pol) PEA/Pol, a biological precursor of resveratrol with antioxidant activity, could have protective effects on oxidative stress produced by inflammatory processes. We evaluated the effects of a comicronized PEA/Pol 10 mg/kg (9 mg of um-PEA+1 mg of polydatin) in a model of Dinitrobenzene sulfonic acid (DNBS)-induced colitis. Ulcerative colitis was induced in mice by intrarectally injection of DNBS (4 mg in 100 µL of 50% ethanol per mouse). Macroscopic and histologic colon alterations and marked clinical signs were observed four days after DNBS and elevated cytokine production. The myeloperoxidase (MPO) activity assessed for neutrophil infiltration was associated with ICAM-1 and P-selectin adhesion controls in colons. Oxidative stress was detected with increased poly ADP-ribose polymerase (PARP) and nitrotyrosine positive staining and malondialdehyde (MDA) levels in inflamed colons. Macroscopic and histologic alterations minimized by oral PEA/Pol, as well as neutrophil infiltration, inflammatory cytokine release, MDA, nitrotyrosine, PARP and ICAM-1, and P-selectin expressions. The mechanism of action of PEA/Pol could be related to the sirtuin 1/nuclear factor erythroid 2-related factor 2 (SIRT-1/Nrf2) pathway and nuclear factor (NF)-κB. PEA/Pol administration inhibited NF-κB and increased SIRT-1/Nrf2 expressions. Our results show that PEA/Pol is capable of decreasing inflammatory bowel disease (IBD) DNBS-induced in mice.


Antioxidants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 465 ◽  
Author(s):  
Victor Udo Nna ◽  
Ainul Bahiyah Abu Bakar ◽  
Azlina Ahmad ◽  
Chinedum Ogbonnaya Eleazu ◽  
Mahaneem Mohamed

Oxidative stress, inflammation and apoptosis are major complications that trigger organ failure in diabetes mellitus (DM), and are proven to adversely affect the male reproductive system. Clinical and experimental studies have demonstrated the promising protective effects of propolis in DM and its associated systemic effects. Herein, we investigated the effect of Malaysian propolis (MP) on testicular oxidative stress, inflammation and apoptosis in diabetic rats. Further, the possibility of a complementary effect of MP with the anti-hyperglycaemic agent, metformin (Met), was studied with the idea of recommending its use in the event that Met alone is unable to contain the negative effects of DM on the male reproductive system in mind. Male Sprague-Dawley rats were either gavaged distilled water (normoglycaemic control and diabetic control groups), MP (diabetic rats on MP), Met (diabetic rats on Met) or MP+Met (diabetic rats on MP+Met), for 4 weeks. MP decreased oxidative stress by up-regulating (p < 0.05) testicular mRNA levels of nuclear factor erythroid 2-related factor 2, superoxide dismutase, catalase and glutathione peroxidase; increasing (p < 0.05) the activities of antioxidant enzymes; and decreasing (p < 0.05) lipid peroxidation in the testes and epididymis of diabetic rats. Further, MP down-regulated (p < 0.05) testicular mRNA and protein levels of pro-inflammatory mediators (nuclear factor kappa B, inducible nitric oxide synthase, tumour necrosis factor-α and interleukin (IL)-1β), decreased (p < 0.05) the nitric oxide level, and increased (p < 0.05) IL-10 mRNA and protein levels. MP also down-regulated (p < 0.05) Bax/Bcl-2, p53, casapase-8, caspase-9 and caspase-3 genes, and increased (p < 0.05) testicular germ cell proliferation. MP’s effects were comparable to Met. However, the best results were achieved following co-administration of MP and Met. Therefore, we concluded that administration of the MP+Met combination better attenuates testicular oxidative stress, inflammation and apoptosis in DM, relative to MP or Met monotherapy, and may improve the fertility of males with DM.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 375
Author(s):  
Hai Jia ◽  
Yunchang Zhang ◽  
Xuemeng Si ◽  
Yuhang Jin ◽  
Da Jiang ◽  
...  

Oxidative stress has been implicated in the etiology of multiple gastrointestinal disorders, such as irritable bowel syndrome and inflammatory bowel disease. This study was conducted to evaluate effects of natural product quercetin on diquat-induced oxidative stress in porcine enterocytes and underlying mechanisms. Intestinal porcine epithelial cell line 1 (IPEC-1) cells pretreated with or without quercetin (5 μM, 24 h) were incubated with vehicle or diquat (100 μM) for 6 h. The results showed that diquat treatment induced apoptosis in a caspase-3-dependent manner, as accompanied by elevated reactive oxygen species (ROS) production, increased mitochondrial depolarization, and reduced the abundance of tight junction proteins. These adverse effects of diquat were remarkably abrogated by quercetin administration. Further study indicated that the protective effect of quercetin was associated with elevated protein abundance of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased intracellular glutathione (GSH) content. Interestingly, the beneficial effects of quercetin on diquat-induced oxidative damage were abolished by all-trans-retinoic acid (Atra), a specific inhibitor of Nrf2, indicating a Nrf2-dependent regulation manner. The results show that quercetin attenuates diquat-induced cell injury by promoting protein abundance of Nrf2 and regulating GSH-related redox homeostasis in enterocytes. These findings provide new insights into a function role of quercetin in maintaining intestinal homeostasis.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Zengxin Jiang ◽  
Mengxuan Bian ◽  
Jingping Wu ◽  
Defang Li ◽  
Lei Ding ◽  
...  

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus (DM). Schwann cell (SC) apoptosis contributes to the occurrence and development of DPN. Effective drugs to prevent SC apoptosis are required to relieve and reverse peripheral nerve injury caused by DM. Oltipraz [4-methyl-5-(2-pyrazinyl)-1,2-dithiole-3-thione], an agonist of nuclear factor erythroid derived-2-related factor 2 (Nrf2), exerts strong effect against oxidative stress in animal models or clinical patients in certain diseases, including heart failure, acute kidney injury, and liver injury. The aim of the present study was to determine the effectiveness of oltipraz in preventing SC apoptosis induced by high glucose levels. RSC96 cells pretreated with oltipraz were cultured in high-glucose medium (50 mM glucose) for 24 h, and cells cultured in medium containing 5 mM glucose were used as the control. Flow cytometry was used to evaluate the degree of apoptosis. A Cell Counting Kit-8 assay was used to assess cell viability. The mitochondrial membrane potential was assessed using JC-1 staining, and reactive oxygen species (ROS) generation was measured using 20,70-dichlorodihydrofluorescein diacetate staining. In addition, the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) levels were also evaluated using the corresponding kits. Flow cytometry was subsequently used to detect apoptosis, and western blotting was used to measure the expression levels of nuclear factor erythroid derived-2-related factor 2 and NADPH quinone oxidoreductase 1. The results showed that high glucose concentration increased oxidative stress and apoptosis in RSC96 cells. Oltipraz improved cell viability and reduced apoptosis of RSC96 cells in the high glucose environment. Additionally, oltipraz exhibited a significant antioxidative effect, as shown by the decrease in MDA levels, increased SOD levels, and reduced ROS generation in RSC96 cells. The results of the present study suggest that oltipraz exhibits potential as an effective drug for treatment with DPN.


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