Correction: Caveolin-1 inhibits expression of antioxidant enzymes through direct interaction with nuclear erythroid 2 p45-related factor-2 (Nrf2).

Background: Alveolar macrophages (AMs) are resident inflammatory cells in the lung that serve as early sentinels of infection or injury. We have identified thioredoxin reductase 1 inhibition by gold compounds increases activation of nuclear factor erythroid 2-related factor 2 (NRF2)-dependent pathways to attenuate inflammatory responses. The present studies utilized murine alveolar macrophages (MH-S) to test the hypothesis that the gold compound, auranofin (AFN), decreases interleukin (IL)-1β expression through NRF2-mediated interactions with nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway genes and/or increases in glutathione synthesis. Methods: MH-S cells were treated with AFN and lipopolysaccharide (LPS) and analyzed at 6 and 24 h. The Il1b promoter was analyzed by chromatin immunoprecipitation for direct interaction with NRF2. Results: Expression of IL-1β, p-IκBα, p-p65 NF-kB, and NOD-, LRR-, and pyrin domain-containing protein 3 were elevated by LPS exposure, but only IL-1β expression was suppressed by AFN treatment. Both AFN and LPS treatments increased cellular glutathione levels, but attenuation of glutathione synthesis by buthionine sulfoximine (BSO) did not alter expression of Il-1β. Analysis revealed direct NRF2 binding to the Il1b promoter which was enhanced by AFN and inhibited the transcriptional activity of DNA polymerase II. Conclusions: Our data demonstrate that AFN-induced NRF2 activation directly suppresses IL-1β synthesis independent of NFκB and glutathione-mediated antioxidant mechanisms. NRF2 binding to the promoter region of IL1β directly inhibits transcription of the IL1β gene. Collectively, our research suggests that gold compounds elicit NRF2-dependent pulmonary protection by suppressing macrophage-mediated inflammation.

Download Full-text

Clostridium butyricum Protects IPEC-J2 Cells from ETEC K88-Induced Oxidative Damage by Activating the Nrf2/ARE Signaling Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/4464002 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Caixia Dou ◽

Zhiyuan Shang ◽

Jiayun Qiao ◽

Yimeng Wang ◽

Haihua Li

Keyword(s):

Antioxidant Enzymes ◽

Oxidative Damage ◽

Signaling Pathway ◽

Antioxidant Response ◽

Clostridium Butyricum ◽

Enterotoxigenic Escherichia Coli ◽

Multiple Infection ◽

Control Group ◽

Related Factor ◽

Viable Bacteria

Clostridium butyricum (CB) is a naturally occurring probiotic compound that can alleviate the oxidative damage induced by enterotoxigenic Escherichia coli K88 (ETEC K88) in porcine intestinal epithelial (IPEC-J2) cells. In this study, we investigate the molecular mechanism underlying this effect. Based on cell viability, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPX) assessments, the optimal concentration of ETEC K88 was determined to be 1 × 10 3 cfu/mL. Viable bacteria counts in cells pretreated with CB and then infected with ETEC K88 show that CB can adhere to IPEC-J2 cells and that optimal adhesion is achieved at the multiple infection index (MOI) of 50 at 3 h of pretreatment. The results of qPCR indicate that although ETEC significantly decreases the expression levels of antioxidant enzymes regulated by NF-E2-related factor 2 (Nrf2) compared to the control group, CB reverses this effect. To confirm that Nrf2 is directly involved in the mechanism by which CB alleviates oxidative stress, siRNA was used to silence the expression of Nrf2 gene in IPEC-J2 cells. Compared to the NC+ETEC and siRNA+ETEC groups, the expressions of SOD1, SOD2, GPX1, and GPX2 in the NC+CB+ETEC and siRNA+CB+ETEC groups are significantly increased at 12 h and 24 h. This shows that CB can reduce ETEC K88-induced oxidative damage in IPEC-J2 cells by activating the expression of antioxidant enzymes implicated in the Kelch-like ECH-associated protein-1- (Keap1-) Nrf2/antioxidant response element (ARE) signaling pathway.

Download Full-text

Increased placental expressions of nuclear factor erythroid 2–related factor 2 and antioxidant enzymes in gestational diabetes: Protective mechanisms against the placental oxidative stress?

European Journal of Obstetrics & Gynecology and Reproductive Biology ◽

10.1016/j.ejogrb.2019.05.016 ◽

2019 ◽

Vol 238 ◽

pp. 78-85 ◽

Cited By ~ 3

Author(s):

Balachandiran Manoharan ◽

Zachariah Bobby ◽

Gowri Dorairajan ◽

Sajini Elizabeth Jacob ◽

Victorraj Gladwin ◽

...

Keyword(s):

Oxidative Stress ◽

Antioxidant Enzymes ◽

Gestational Diabetes ◽

Related Factor ◽

Nuclear Factor ◽

Protective Mechanisms ◽

Placental Oxidative Stress

Download Full-text

Quercetin protects the buffalo rat liver (BRL-3A) cells from aflatoxin B1-induced cytotoxicity via activation of Nrf2-ARE pathway

World Mycotoxin Journal ◽

10.3920/wmj2019.2465 ◽

2020 ◽

Vol 13 (2) ◽

pp. 299-312

Author(s):

X. Wang ◽

L. Li ◽

G. Zhang

Keyword(s):

Oxidative Stress ◽

Antioxidant Enzymes ◽

Rat Liver ◽

Chromatin Condensation ◽

Dna Integrity ◽

Related Factor ◽

Mitochondria Membrane Potential ◽

Lactate Dehydrogenase Release ◽

Phosphorylated Akt ◽

Pre Treatment

Aflatoxin B1 (AFB1) is the most toxic mycotoxin widely presented in agricultural products, and the protective effect of quercetin (QUE), a natural antioxidant, against AFB1-induced cytotoxicity to the buffalo rat liver (BRL-3A) cells was investigated. With an IC50 of 23 μM, AFB1 induced a significant oxidative stress to BRL-3A cells evidenced by a dose-dependent reduction of mitochondria membrane potential (MMP), ATP content, and activities of endogenous antioxidant enzymes along with increased levels of reactive oxygen species (ROS) and lipid peroxidation biomarker of malondialdehyde (MDA). The activity of CYP1A2, the key enzyme to convert AFB1 to reactive AFB1 exo-8,9- epoxide, was also increased, which, probably in together with ROS, led to cell apoptosis with DNA fragmentation, chromatin condensation and increased lactate dehydrogenase release. After the BRL cells were pre-treated by low level QUE (2.5 and/or 5 μM) for 24 h and then exposed to AFB1, the activities of antioxidant enzymes including haeme oxygenase-1, glutathione S-transferase, superoxide dismutase, and the ratio of reduced to oxidised glutathione were significantly increased whereas the levels of intracellular ROS and MDA were reduced. The QUE pre-treatment also increased the levels of MMP, ATP and DNA integrity, and reduced the expression of apoptosis related genes of Bax and Caspase-3. The Western blotting study revealed increased content of phosphorylated Akt and nuclear NF-E2-related factor 2 (Nrf2), indicating an activation of Nrf2-ARE pathway in counteracting oxidative stress and cytotoxicity of AFB1. Thus, the QUE pre-treatment enhanced the anti-stress capacity of the cells through the activation of the Nrf2-ARE pathway, and QUE-based measures could be developed to ameliorate the toxicity caused by AFB1.

Download Full-text

Melatonin prevents the decreased activity of antioxidant enzymes and activates nuclear erythroid 2-related factor 2 signaling in an animal model of fulminant hepatic failure of viral origin

Journal of Pineal Research ◽

10.1111/j.1600-079x.2010.00787.x ◽

2010 ◽

pp. no-no ◽

Cited By ~ 13

Author(s):

Irene Crespo ◽

Beatriz S. Miguel ◽

Almudena Laliena ◽

Marcelino Álvarez ◽

Jesús M. Culebras ◽

...

Keyword(s):

Animal Model ◽

Antioxidant Enzymes ◽

Fulminant Hepatic Failure ◽

Hepatic Failure ◽

Related Factor ◽

Viral Origin

Download Full-text

Association of Vibrio parahaemolyticus Thermostable Direct Hemolysin with Lipid Rafts Is Essential for Cytotoxicity but Not Hemolytic Activity

Infection and Immunity ◽

10.1128/iai.00946-09 ◽

2009 ◽

Vol 78 (2) ◽

pp. 603-610 ◽

Cited By ~ 38

Author(s):

Shigeaki Matsuda ◽

Toshio Kodama ◽

Natsumi Okada ◽

Kanna Okayama ◽

Takeshi Honda ◽

...

Keyword(s):

Lipid Rafts ◽

Hemolytic Activity ◽

Vibrio Parahaemolyticus ◽

Cultured Cells ◽

Direct Interaction ◽

Caveolin 1 ◽

Marker Proteins ◽

Thermostable Direct Hemolysin ◽

Target Molecules

ABSTRACT Thermostable direct hemolysin (TDH), a major virulence factor of Vibrio parahaemolyticus, induces cytotoxicity in cultured cells. However, the mechanism of TDH's cytotoxic effect including its target molecules on the plasma membrane of eukaryotic cells remains unclear. In this study, we identified the role of lipid rafts, cholesterol- and sphingolipid-enriched microdomains, in TDH cytotoxicity. Treatment of cells with methyl-β-cyclodextrin (MβCD), a raft-disrupting agent, inhibited TDH cytotoxicity. TDH was associated with detergent-resistant membranes (DRMs), and MβCD eliminated this association. In contrast, there was no such association between a nontoxic TDH mutant and DRMs. The disruption of lipid rafts neither affected hemolysis nor inhibited Ca2+ influx into HeLa cells induced by TDH. These findings indicate that the cytotoxicity but not the hemolytic activity of TDH is dependent on lipid rafts. The exogenous and endogenous depletion of cellular sphingomyelin also prevented TDH cytotoxicity, but a direct interaction between TDH and sphingomyelin was not detected with either a lipid overlay assay or a liposome absorption test. Treatment with sphingomyelinase (SMase) at 100 mU/ml disrupted the association of TDH with DRMs but did not affect the localization of lipid raft marker proteins (caveolin-1 and flotillin-1) with DRMs. These results suggest that sphingomyelin is important for the association of TDH with lipid rafts but is not a molecular target of TDH. We hypothesize that TDH may target a certain group of rafts that are sensitive to SMase at a certain concentration, which does not affect other types of rafts.

Download Full-text

Inhibition of nuclear factor-erythroid 2–related factor (Nrf2) by caveolin-1 promotes stress-induced premature senescence

Molecular Biology of the Cell ◽

10.1091/mbc.e12-09-0666 ◽

2013 ◽

Vol 24 (12) ◽

pp. 1852-1862 ◽

Cited By ~ 68

Author(s):

Daniela Volonte ◽

Zhongmin Liu ◽

Paul M. Musille ◽

Elena Stoppani ◽

Nobunao Wakabayashi ◽

...

Keyword(s):

Oxidative Stress ◽

Amino Acids ◽

Null Mouse ◽

Related Factor ◽

Mutant Form ◽

Premature Senescence ◽

Caveolin 1 ◽

Functional Studies ◽

Age Related ◽

Nrf2 Target Gene

Reactive oxygen species (ROS) can induce premature cellular senescence, which is believed to contribute to aging and age-related diseases. The nuclear erythroid 2 p45–related factor-2 (Nrf2) is a transcription factor that mediates cytoprotective responses against stress. We demonstrate that caveolin-1 is a direct binding partner of Nrf2, as shown by the binding of the scaffolding domain of caveolin-1 (amino acids 82–101) to the caveolin-binding domain of Nrf2 (amino acids 281–289). Biochemical studies show that Nrf2 is concentrated into caveolar membranes in human and mouse fibroblasts, where it colocalizes with caveolin-1, under resting conditions. After oxidative stress, caveolin-1 limits the movement of Nrf2 from caveolar membranes to the nucleus. In contrast, Nrf2 is constitutively localized to the nucleus before and after oxidative stress in caveolin-1–null mouse embryonic fibroblasts (MEFs), which do not express caveolin-1. Functional studies demonstrate that caveolin-1 acts as an endogenous inhibitor of Nrf2, as shown by the enhanced up-regulation of NQO1, an Nrf2 target gene, in caveolin-1–null MEFs and the activation or inhibition of a luciferase construct carrying an antioxidant responsive element (ARE) after down-regulation of caveolin-1 by small interfering RNA or overexpression of caveolin-1, respectively. Expression of a mutant form of Nrf2 that cannot bind to caveolin-1 (Φ→A-Nrf2) hyperactivates ARE and inhibits oxidative stress–induced activation of the p53/p21Waf1/Cip1 pathway and induction of premature senescence in fibroblasts. Finally, we show that overexpression of caveolin-1 in colon cancer cells inhibits oxidant-induced activation of Nrf2-dependent signaling, promotes premature senescence, and inhibits their transformed phenotype. Thus, by inhibiting Nrf2-mediated signaling, caveolin-1 links free radicals to the activation of the p53/senescence pathway.

Download Full-text

Endothelial Nitric Oxide Synthase and Its Negative Regulator Caveolin-1 Localize to Distinct Perinuclear Organelles

Journal of Histochemistry & Cytochemistry ◽

10.1177/002215540205000604 ◽

2002 ◽

Vol 50 (6) ◽

pp. 779-788 ◽

Cited By ~ 36

Author(s):

Roland Govers ◽

Peter van der Sluijs ◽

Elly van Donselaar ◽

Jan-Willem Slot ◽

Ton J. Rabelink

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Golgi Complex ◽

Endothelial Nitric Oxide Synthase ◽

Direct Interaction ◽

Negative Regulator ◽

Caveolin 1 ◽

Enos Activity ◽

Oxide Synthase ◽

Endothelial Nitric Oxide

Caveolin-1 is a member of a subset of intracellular proteins that regulate endothelial nitric oxide synthase (eNOS) activity. In caveolae, caveolin-1 inhibits eNOS activity via a direct interaction with the enzyme. Previous work has indicated that both eNOS and caveolin-1 are also localized at the perinuclear Golgi complex. Whether caveolin-1 is involved in eNOS regulation in this cell compartment is unknown. Here we studied the localization of eNOS and caveolin-1 in the perinuclear region of primary bovine aortic endothelial cells. By immunofluorescence microscopy we show that both eNOS and caveolin-1 co-localize with Golgi markers. On treatment of the cells with the microtubule-depolymerizing drug nocodazole, the Golgi complex is scattered and caveolin-1 is found in vesicles at the periphery of the cell, while eNOS is localized at large structures near the nucleus. The nocodazole-induced redistribution of eNOS is similar to that of cis-, medial-, and trans-Golgi markers, while the caveolin-1 redistribution resembles that of sec22, a marker for the intermediate compartment. The localization of eNOS and caveolin-1 at distinct perinuclear compartments that behave differently in the presence of nocodazole indicates that eNOS activity is not regulated by caveolin-1 in the Golgi complex.

Download Full-text