Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, we have used the rat model of hyperoxia to examine the molecular responses to oxidative stress in lung. We show that in addition to the antioxidant enzyme manganese superoxide dismutase, expression of a variety of stress-responsive genes including heme oxygenase-1, c-fos, c-jun, CAAT-enhancer binding protein (C/EBP)-beta, and C/EBP-delta were increased after hyperoxia. Increased c-fos, c-jun, C/EBP-beta, and C/EBP-delta mRNA expression was correlated with increased DNA binding activity of the transcription factor complexes activator protein 1 and C/EBP in tissue lysates. Because oxidative damage plays an important role in the aging process and little is known about the susceptibility of aged rats to hyperoxia, we also examined the relative tolerance of old rats to hyperoxia. Surprisingly, we observed that aged rats exhibit greater tolerance to hyperoxic stress than young rats. Old rats exhibited decreased arterial oxygen tension when compared to young rats after hyperoxia exposure. This increased tolerance coincided with decreased albumin levels in bronchoalveolar lavage and the delayed onset of activation of transcription factors and expression of oxidative stress-inducible genes in old rats. Transcription factor and stress-response gene activation may serve as useful molecular markers for oxidant lung injury.
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PMID:Molecular responses to hyperoxia in vivo: relationship to increased tolerance in aged rats. 759 40

Reactive oxygen species (ROS) are important second messengers for the induction of several genes in a variety of physiological and pathological conditions. Here we addressed the question of whether isolated, unbalanced overexpression of the antioxidant enzyme manganese superoxide dismutase (Mn-SOD) may modulate signal transduction cascades, finally leading to connective tissue degradation, a hallmark in carcinogenesis and aging. Therefore, we generated stably Mn-SOD-overexpressing fibroblasts with an up to 4. 6-fold increase in Mn-SOD activity. The Mn-SOD-overexpressing cells revealed specific resistance to the superoxide anion (O-(2))-generating agent paraquat, whereas no resistance to UVA-generated oxidative stress was found. Treatment of the Mn-SOD-overexpressing cells with various ROS-generating systems resulted (due to the enhanced dismutation of superoxide anion to hydrogen peroxide) in an up to 9.5-fold increase in matrix-degrading metalloprotease-1 (MMP-1) mRNA levels. A similar increase in MMP-1 mRNA was also seen when the intracellular H(2)O(2) concentration was increased by the inhibition of different H(2)O(2)-detoxifying pathways. Furthermore, prooxidant conditions led to a strong induction of c-jun and c-fos mRNA levels resulting in a 4-fold higher transactivation of the transcription factor AP-1 in the Mn-SOD-overexpressing cells. Collectively, we have found that enhanced Mn-SOD activity, via an unbalanced H(2)O(2) overproduction and detoxification, induces MMP-1 mRNA levels, and this effect is at least partly mediated by the DNA recognition sequence AP-1.
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PMID:Stable overexpression of manganese superoxide dismutase in mitochondria identifies hydrogen peroxide as a major oxidant in the AP-1-mediated induction of matrix-degrading metalloprotease-1. 1046 29

There is now increasing evidence that an oxidant/antioxidant imbalance, in favor of oxidants, occurs in chronic obstructive pulmonary disease (COPD). Evidence is also accumulating that oxidative stress is a critical event in the pathogenesis of this condition. A large number of studies have demonstrated an increased oxidant burden and consequently increased markers of oxidative stress in the airspaces, breath, blood, and urine of smokers and of patients with COPD. There are several events related to oxidative stress, which are important in the pathogenesis of COPD. These include oxidative inactivation of antiproteinases, airspace epithelial injury, increased sequestration of neutrophils in the pulmonary microvasculature, and gene expression of proinflammatory mediators. Oxidative processes have a fundamental role in the inflammation of smokers and patients with COPD, through redox-sensitive transcription factors such as NF-kappaB and AP-1, which regulate the genes for proinflammatory mediators and protective mechanisms, such as antioxidant gene expression. In addition to the oxidative stress produced by cigarette smoking, dietary deficiency in antioxidants is related to the development of airflow limitation, and hence dietary supplementation may be a beneficial therapeutic intervention in this condition. The use of antioxidants with good bioavailability or molecules that have antioxidant enzyme activity may be treatments that not only protect against the direct injurious effects of oxidants, but may fundamentally alter the inflammatory events that are thought to play an important part in the pathogenesis of COPD. MacNee W, Rahman I. Oxidants and antioxidants as therapeutic targets in chronic obstructive pulmonary disease.
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PMID:Oxidants and antioxidants as therapeutic targets in chronic obstructive pulmonary disease. 1055 72

Diesel exhaust particles (DEP) contain organic chemicals that contribute to the adverse health effects of inhaled particulate matter. Because DEP induce oxidative stress in the lung and in macrophages, effective antioxidant defenses are required. One type of defense is through the expression of the antioxidant enzyme, heme oxygenase I (HO-1). HO-1 as well as phase II detoxifying enzymes are induced via antioxidant response elements (ARE) in their promoters of that gene. We show that a crude DEP total extract, aromatic and polar DEP fractions, a benzo(a)pyrene quinone, and a phenolic antioxidant induce HO-1 expression in RAW264.7 cells in an ARE-dependent manner. N-acetyl cysteine and the flavonoid, luteolin, inhibited HO-1 protein expression. We also demonstrate that the same stimuli induce HO-1 mRNA expression in parallel with the activation of the SX2 enhancer of that gene. Mutation of the ARE core, but not the overlapping AP-1 binding sequence, disrupted SX2 activation. Finally, we show that biological agents, such as oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, could also induce HO-1 expression via an ARE-dependent mechanism. Prior induction of HO-1 expression, using cobalt-protoporphyrin, protected RAW264.7 cells against DEP-induced toxicity. Taken together, these data show that HO-1 plays an important role in cytoprotection against redox-active DEP chemicals, including quinones.
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PMID:Induction of heme oxygenase-1 expression in macrophages by diesel exhaust particle chemicals and quinones via the antioxidant-responsive element. 1097 58

The mitochondrial antioxidant enzyme manganese-containing superoxide dismutase (MnSOD) functions as a tumor suppressor gene. Reconstitution of MnSOD expression in several human cancer cell lines leads to reversion of malignancy and induces a resistant phenotype to the cytotoxic effects of TNF and hyperthermia. The signaling pathways that underlie these phenotypic changes in MnSOD-overexpressing cells are unknown, although alterations in the activity of several redox-sensitive transcription factors, including AP-1 and NF-kappaB, have been observed. To determine the downstream signaling molecules involved in MnSOD-induced cell resistant phenotype, in the present study we analyzed the expression profile of several groups of genes related to stress response, DNA repair, and apoptosis, in a human breast cancer MCF-7 cell line overexpressing MnSOD (MCF+SOD). Of 588 genes examined, 5 (0.85%) were up-regulated (2-42-fold), and 11 (1.9%) were down-regulated (2-33-fold) in the MCF+SOD cells compared to the parental MCF-7 cells. The five up-regulated genes were MET, GADD153, CD9, alpha-catenin and plakoglobin. The genes with the most significant down-regulation included: vascular endothelial growth factor receptor 1, TNF-alpha converting enzyme, and interleukin-1beta. GADD153 (involved in the repair of DNA double strand breaks) showed a 33-fold increase in microarray analysis and these results were confirmed by RT-PCR. To further determine the specificity in MnSOD-induced gene regulation, MCF+SOD cells were stably transfected with an antisense MnSOD sequence whose expression was controlled by a tetracycline-inducible regulator. Expression of three up-regulated genes was measured after induction of antisense MnSOD expression. Interestingly, expression level of GADD153 but not MET or CD9 was reduced 24 h after antisense MnSOD induction. Together, these results suggest that reconstitution of MnSOD in tumor cells can specifically modulate the expression of down-stream effector genes. GADD153 and other elements observed in the MCF+SOD cells may play a key role in signaling the MnSOD-induced cell phenotypic change.
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PMID:Genes regulated in human breast cancer cells overexpressing manganese-containing superoxide dismutase. 1116 72

There is now considerable evidence for an increased oxidant burden in smokers, particularly in those smokers who develop chronic obstructive pulmonary disease (COPD), as shown by increased markers of oxidative stress in the airspaces, breath, blood and urine. The presence of increased oxidative stress is a critical feature in the pathogenesis of COPD, since it results in inactivation of antiproteinases, airspace epithelial injury, mucus hypersecretion, increased sequestration of neutrophils in the pulmonary microvasculature, and gene expression of pro-inflammatory mediators. The sources of the increased oxidative stress in patients with COPD derive from the increased burden of oxidants present in cigarette smoke, or from the increased amounts of reactive oxygen species released from leukocytes, both in the airspaces and in the blood. Antioxidant depletion or deficiency in antioxidants also contributes to oxidative stress. The development of airflow limitation is related to dietary deficiency of antioxidants and hence dietary supplementation may be a beneficial therapeutic intervention in this condition. Oxidative stress also has a role in enhancing the airspace inflammation, which occurs in smokers and patients with COPD through the activation of redox-sensitive transcriptions factors such as NF-kappa B and AP-1, which regulate the genes for pro-inflammatory mediators and protective antioxidant gene expression. Antioxidants that have good bioavailability or molecules that have antioxidant enzyme activity are therefore therapies that not only protect against the direct injurious effects of oxidants, but also may fundamentally alter the inflammatory events which have a central role in the pathogenesis of COPD.
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PMID:Oxidants/antioxidants and chronic obstructive pulmonary disease: pathogenesis to therapy. 1119 95

Manganese-superoxide dismutase (Sod2) removes mitochondrially derived superoxide (O(2)) at near-diffusion limiting rates and is the only antioxidant enzyme whose expression is regulated by numerous stimuli. Here it is shown that Sod2 also serves as a source of the intracellular signaling molecule H(2)O(2). Sod2-dependent increases in the steady-state levels of H(2)O(2) led to ERK1/2 activation and subsequent downstream transcriptional increases in matrix metalloproteinase-1 (MMP-1) expression, which were reversed by expression of the H(2)O(2)-detoxifying enzyme, catalase. In addition, a single nucleotide polymorphism has recently been identified (1G/2G) at base pair--1607 that creates an Ets site adjacent to an AP-1 site at base pair --1602 and has been shown to dramatically enhance transcription of the MMP-1 promoter. Luciferase promoter constructs containing either the 1G or 2G variation were 25- or 1000-fold more active when transiently transfected into Sod2-overexpressing cell lines, respectively. The levels of MMP-2, -3, and -7 were also increased in the Sod2-overexpressing cell lines, suggesting that Sod2 may function as a "global" redox regulator of MMP expression. In addition, Sod2(-/+) mouse embryonic fibroblasts failed to respond to the cytokine-mediated induction of the murine functional analog of MMP-1, MMP-13. This study provides evidence that the modulation of Sod2 activity by a wide array of pathogenic and inflammatory stimuli may be utilized by the cell as a primary signaling mechanism leading to matrix metalloproteinase expression.
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PMID:Manganese superoxide dismutase signals matrix metalloproteinase expression via H2O2-dependent ERK1/2 activation. 1129 30

Maintaining mobility is a critical element for the quality of life. Skeletal muscle, the primary organ for locomotion, undergoes age-associated deterioration in size, structure, and function. Recent research suggests that oxidative stress is an important etiology for sarcopenia. The level of oxidative stress imposed on aging muscle is influenced by two fundamental biological processes: the increased generation of reactive oxygen species (ROS) and age-associated changes in antioxidant defense. It appears that despite increased ROS production, aging muscle has a decreased gene expression of antioxidant enzymes possibly due to a diminished ability for cell signaling. A major benefit of nonexhaustive exercise is to induce a mild oxidative stress that stimulates the expression of certain antioxidant enzymes. This is mediated by the activation of redox-sensitive signaling pathways. For example, gene expression of muscle mitochondrial (Mn) superoxide dismutase is enhanced after an acute bout of exercise preceded by an elevated level of NF-kappaB and AP-1 binding. An increase in de novo protein synthesis of an antioxidant enzyme usually requires repeated bouts of exercise. Aging does not abolish but seems to attenuate training adaptations of antioxidant enzymes. Thus, for senescent muscle, training should be assisted with supplementation of exogenous antioxidants to research the optimal level of defense.
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PMID:Exercise-induced modulation of antioxidant defense. 1197 88

Extracellular superoxide dismutase (ECSOD) is a major extracellular antioxidant enzyme that protects organs from damage by reactive oxygen species (ROS). We cloned a novel ECSOD from the bay scallop Argopecten irradians (AiECSOD) by 3' and 5' RACE. The full-length cDNA of AiECSOD was 893bp with a 657bp open reading frame encoding 218 amino acids. The deduced amino acid sequence contained a putative signal peptide of 20 amino acids, and sequence comparison showed that AiECSOD had low degree of homology to ECSODs of other organisms. The genomic length of the AiECSOD gene was about 5276bp containing five exons and six introns. The promoter region contained many putative transcription factor binding sites such as c-Myb, Oct-1, Sp1, Kruppel-like, c-ETS, NFkappaB, GATA-1, AP-1, and Ubx binding sites. Furthermore, tissue-specific expressions of AiECSOD and temporal expressions of AiECSOD in haemocytes of bay scallops challenged with bacteria Vibrio anguillarum were quantified using qRT-PCR. High levels of expression were detected in haemocytes, but not in gonad and mantle. The expression of AiECSOD reached the highest level at 12h post-injection with V. anguillarum and then returned to normal between 24h and 48h post-injection. These results indicated that AiECSOD was an inducible protein and that it may play an important role in the immune responses against V. anguillarum.
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PMID:Cloning, characterization, and expression analysis of extracellular copper/zinc superoxide dismutase gene from bay scallop Argopecten irradians. 1908 69

Oxidative stress plays an important role in the pathogenesis of pulmonary fibrosis. Heme oxygenase-1 (HO-1) is a key antioxidant enzyme, and overexpression of HO-1 significantly decreases lung inflammation and fibrosis in animal models. Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a transcription factor that regulates adipogenesis, insulin sensitization, and inflammation. We report here that the PPARgamma ligands 15d-PGJ2 and 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), which have potent antifibrotic effects in vitro, also strongly induce HO-1 expression in primary human lung fibroblasts. Pharmacological and genetic approaches are used to demonstrate that induction of HO-1 is PPARgamma independent. Upregulation of HO-1 coincides with decreased intracellular glutathione (GSH) levels and can be inhibited by N-acetyl cysteine (NAC), a thiol antioxidant and GSH precursor. Upregulation of HO-1 is not inhibited by Trolox, a non-thiol antioxidant, and does not involve the transcription factors AP-1 or Nrf2. CDDO and 15d-PGJ2 contain an alpha/beta unsaturated ketone that acts as an electrophilic center that can form covalent bonds with free reduced thiols. Rosiglitazone, a PPARgamma ligand that lacks an electrophilic center, does not induce HO-1. These data suggest that in human lung fibroblasts, 15d-PGJ2 and CDDO induce HO-1 via a GSH-dependent mechanism involving the formation of covalent bonds between 15d-PGJ2 or CDDO and GSH. Inhibiting HO-1 upregulation with NAC has only a small effect on the antifibrotic properties of 15d-PGJ2 and CDDO in vitro. These results suggest that CDDO and similar electrophilic PPARgamma ligands may have great clinical potential as antifibrotic agents, not only through direct effects on fibroblast differentiation and function, but indirectly by bolstering antioxidant defenses.
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PMID:Peroxisome proliferator-activated receptor-gamma ligands induce heme oxygenase-1 in lung fibroblasts by a PPARgamma-independent, glutathione-dependent mechanism. 1973 19


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