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)

Lysophosphatidylcholine (lysoPC) evokes diverse biological responses in vascular cells including Ca(2+) mobilization, production of reactive oxygen species, and activation of the mitogen-activated protein kinases, but the mechanisms linking these events remain unclear. Here, we provide evidence that the response of mitochondria to the lysoPC-dependent increase in cytosolic Ca(2+) leads to activation of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase through a redox signaling mechanism in human umbilical vein endothelial cells. ERK activation was attenuated by inhibitors of the electron transport chain proton pumps (rotenone and antimycin A) and an uncoupler (carbonyl cyanide p-trifluoromethoxyphenylhydrazone), suggesting that mitochondrial inner membrane potential plays a key role in the signaling pathway. ERK activation was also selectively attenuated by chain-breaking antioxidants and by vitamin E targeted to mitochondria, suggesting that transduction of the mitochondrial hydrogen peroxide signal is mediated by a lipid peroxidation product. Inhibition of ERK activation with MEK inhibitors (PD98059 or U0126) diminished induction of the antioxidant enzyme heme oxygenase-1. Taken together, these data suggest a role for mitochondrially generated reactive oxygen species and Ca(2+) in the redox cell signaling path-ways, leading to ERK activation and adaptation of the pathological stress mediated by oxidized lipids such as lysoPC.
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PMID:Activation of mitogen-activated protein kinases by lysophosphatidylcholine-induced mitochondrial reactive oxygen species generation in endothelial cells. 1665 38

Rickettsiae, a diverse group of obligately intracellular gram-negative bacteria, include etiologic agents of the spotted fever and typhus groups of diseases. Rocky Mountain spotted fever and boutonneuse fever, due to Rickettsia rickettsii and R. conorii, respectively, are characterized by widespread infection of the vascular endothelium, microvascular injury, and vasculitis. Cultured human endothelial cells (EC) are highly susceptible to infection and respond by altering the expression of adhesion molecules, regulatory cytokines, and the antioxidant enzyme heme oxygenase (HO). In the vasculature, HO regulates the cyclooxygenase (COX) enzymes, among which the inducible isozyme COX-2 facilitates the synthesis of prostaglandins (PGs). Using in vitro and ex vivo models of infection, we demonstrate here that R. rickettsii infection of human EC causes robust induction of COX-2 mRNA and protein expression but has no apparent effect on the constitutive COX-1 isoform. Cells infected with viable rickettsiae consistently displayed significantly increased secretion of 6-keto-PGF(1alpha) and PGE(2). R. rickettsii-induced COX-2 was sensitive to inhibitors of de novo transcription and the pyridinylimidazole-based compound SB 203580, suggesting that this transcriptional host cell response involves signaling through p38 mitogen-activated protein kinase. PG production by infected cells was abrogated by NS 398 (a selective COX-2 inhibitor) and indomethacin (a pan-COX inhibitor). Immunohistochemical staining of sections of infected umbilical cords and corresponding uninfected controls revealed comparatively more intense and abundant staining for COX-2 in infected endothelia. Induction of the endothelial COX-2 system and the resultant enhanced release of vasoactive PGs may contribute to the regulation of inflammatory responses and vascular permeability changes during spotted fever rickettsioses.
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PMID:Infection of human endothelial cells with spotted Fever group rickettsiae stimulates cyclooxygenase 2 expression and release of vasoactive prostaglandins. 1692 98

NO is known to induce expression of heme oxygenase-1, an antioxidant enzyme in blood vessels. We tested whether NO might modulate the endothelial NADPH oxidase function via heme oxygenase-1. In human microvascular endothelial cells, the NO donor DETA-NONOate (0.1 to 1 mmol/L) strongly induced expression of heme oxygenase-1 but not Cu/Zn superoxide dismutase. This was associated with a reduction of the superoxide-generating capacity of NADPH oxidase, an effect that depended on de novo gene transcription and heme oxygenase-1 activity. Activation of NADPH oxidase by tumor necrosis factor (TNF) alpha increased generation of reactive oxygen species. DETA-NONOate alone had little effect on TNF-stimulated reactive oxygen species, but it enhanced the TNF response when: (1) heme oxygenase-1 expression was blocked with specific small-interfering RNA; (2) heme oxygenase-1 activity was blocked by zinc-protoporphyrin; or (3) NADPH oxidase activity was blocked by diphenyleneiodonium. Moreover, the heme oxygenase-1 end product bilirubin directly inhibited fully functional NADPH oxidase and seemed to interrupt the assembly and activation of the oxidase. In conclusion, NO may modulate superoxide production by NADPH oxidase in human vascular endothelial cells, at least partly by inducing heme oxygenase-1. Our results indicate that suppression of NADPH oxidase-dependent reactive oxygen species formation may represent a novel mechanism underlying the cardiovascular protective actions of heme oxygenase-1 and bilirubin.
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PMID:NO modulates NADPH oxidase function via heme oxygenase-1 in human endothelial cells. 1698 56

Photodynamic therapy (PDT) is an established anticancer modality utilizing the photogeneration of reactive oxygen species (ROS) to kill the cancer cells and hypericin is a promising photosensitizer for the treatment of bladder tumors. In this paper we characterize the signaling pathways and the mechanisms leading to the up-regulation of the antioxidant enzyme heme oxygenase (HO-1) in PDT treated cancer cells. We show that PDT engages the p38(MAPK) and PI3K signaling cascades for HO-1 induction. p38(MAPK) inhibitors or small interfering RNA (siRNA) for p38(MAPK) suppress HO-1 induction after PDT and complete repression is attained when p38 and PI3K antagonists are combined. Blocking these signaling pathways increases additively the propensity of the cells to undergo PDT-induced apoptosis, mirroring the effect of HO-1 silencing. Conversely, increasing HO-1 protein level by hemin prior to irradiation is cytoprotective. HO-1 stimulation by PDT is dependent on transcription and de novo protein synthesis and it is preceded by the nuclear accumulation of the Nrf2 transcription factor, which is reduced by inhibitors of p38(MAPK) and PI3K. Altogether these results indicate that stimulation of HO-1 expression by hypericin-PDT is a cytoprotective mechanism governed by the p38(MAPK) and PI3K pathways, likely through the control of the nuclear availability of the Nrf2 pool.
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PMID:Induction of heme-oxygenase 1 requires the p38MAPK and PI3K pathways and suppresses apoptotic cell death following hypericin-mediated photodynamic therapy. 1721 54

Increased production of reactive oxygen species (ROS) and loss of endothelial NO bioavailability are key features of vascular disease in diabetes mellitus. The p66(Shc) adaptor protein controls cellular responses to oxidative stress. Mice lacking p66(Shc) (p66(Shc-/-)) have increased resistance to ROS and prolonged life span. The present work was designed to investigate hyperglycemia-associated changes in endothelial function in a model of insulin-dependent diabetes mellitus p66(Shc-/-) mouse. p66(Shc-/-) and wild-type (WT) mice were injected with citrate buffer (control) or made diabetic by an i.p. injection of 200 mg of streptozotocin per kg of body weight. Streptozotocin-treated p66(Shc-/-) and WT mice showed a similar increase in blood glucose. However, significant differences arose with respect to endothelial dysfunction and oxidative stress. WT diabetic mice displayed marked impairment of endothelium-dependent relaxations, increased peroxynitrite (ONOO(-)) generation, nitrotyrosine expression, and lipid peroxidation as measured in the aortic tissue. In contrast, p66(Shc-/-) diabetic mice did not develop these high-glucose-mediated abnormalities. Furthermore, protein expression of the antioxidant enzyme heme oxygenase 1 and endothelial NO synthase were up-regulated in p66(Shc-/-) but not in WT mice. We report that p66(Shc-/-) mice are resistant to hyperglycemia-induced, ROS-dependent endothelial dysfunction. These data suggest that p66(Shc) adaptor protein is part of a signal transduction pathway relevant to hyperglycemia vascular damage and, hence, may represent a novel therapeutic target against diabetic vascular complications.
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PMID:Genetic deletion of p66(Shc) adaptor protein prevents hyperglycemia-induced endothelial dysfunction and oxidative stress. 1736 Mar 81

Oxidative stress is thought to play a major role in the pathogenesis of chronic obstructive pulmonary disease, characterized by impaired lung function. A large number (> or =33) of GT repeats (L-allele) in the gene of the powerful antioxidant enzyme heme oxygenase-1 has been associated with susceptibility to accelerated lung function decline. In contrast, beta-carotene may help to protect against accelerated decline. To determine whether high serum levels of beta-carotene might counterbalance the greater susceptibility of L-allele carriers, the authors analyzed the annual decline in forced expiratory volume in 1 second (FEV1) in a general population sample of 523 French subjects (20-44 years, 50% men) examined in 1992 and 2000 as part of the European Community Respiratory Health Survey. Analysis of covariance, adjusted for sex as well as baseline age, body mass index, smoking, and FEV1, showed that, among subjects with low beta-carotene levels, L-allele carriers experienced a steeper mean FEV1 decline than did noncarriers (mean = -58.8, 95% confidence interval: -73.2, -44.5 vs. mean = -34.7, 95% confidence interval: -38.9, -29.8 ml/year) (p = 0.009), whereas among subjects with high beta-carotene levels, the FEV1 decline was not different in L-allele carriers and noncarriers (two-sided p = 0.9). The results suggest that high levels of beta-carotene might counterbalance the effects on FEV1 decline of a genetically determined deficiency in antioxidant response.
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PMID:Interaction between a heme oxygenase-1 gene promoter polymorphism and serum beta-carotene levels on 8-year lung function decline in a general population: the European Community Respiratory Health Survey (France). 1797 38

Angiotensin II (Ang II) is a peptide hormone able to elicit a strong production of reactive oxygen species by human neutrophils. In this work, we have addressed whether expression of heme oxygenase-1 (HO-1), an antioxidant enzyme, becomes altered in these cells upon Ang II treatment or under hypertension conditions. In neutrophils from healthy and hypertensive subjects, induction of HO-1 mRNA and protein expression with a parallel increase in enzyme activity took place upon treatment with 15-deoxy-Delta12,14-PGJ2 (15dPGJ2). However, Ang II prevented HO-1 synthesis by normal neutrophils in vitro, and HO-1 expression was depressed in neutrophils from hypertensive patients in comparison with cells from healthy subjects. In addition, Ang II treatment led to a reduced HO-1 enzyme activity to levels similar to those found in neutrophils from hypertensive patients. NO donors reversed the inhibition of 15dPGJ2-dependent HO-1 expression in neutrophils from hypertensive patients, and conversely, inhibition of inducible NO synthase (NOS2) activity counteracted the stimulatory effect of 15dPGJ2 on HO-1 expression in normal human neutrophils. Moreover, Ang II canceled 15dPGJ2-dependent induction of NOS2 mRNA synthesis. Present findings indicate that down-regulation of HO-1 expression in neutrophils from hypertensive subjects is likely exerted through the inhibition of NOS2 expression. Additionally, they underscore the potential usefulness of NO donors as new, therapeutic agents against hypertension.
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PMID:Heme oxygenase-1 expression is down-regulated by angiotensin II and under hypertension in human neutrophils. 1851 25

An increase in oxidative stress is suggested to be intimately involved in the pathogenesis of heart failure. Phenolic acids are widespread in plant foods; they contain important biological and pharmacological properties. This study evaluated the role of phenolic acids on the expression of antioxidant enzymes in the heart of male Sprague-Dawley rats. Gallic acid, ferulic acid and p-coumaric acid at a dosage of 100 mg kg(-1) body weight significantly increased the activities of cardiac superoxide dismutase, glutathione peroxidase (GPx) and catalase (CAT) as compared with control rats (P<.05). The changes in cardiac CuZnSOD, GPx and CAT mRNA levels induced by phenolic acids were similar to those noted in the enzyme activity levels. A significant (P<.05) increase in the GSH/GSSG ratio was observed in the heart of phenolic acid-treated rats. The heart homogenates obtained from rats that were administered phenolic acids displayed significant (P<.05) increases in capacity for oxygen radical absorbance compared with control rats. Immunoblot analysis revealed the increased cardiac total level of Nrf2 in phenolic acid-treated rats. Interestingly, phenolic acid-mediated antioxidant enzyme expression was accompanied by up-regulation of heme oxygenase-1. This study demonstrates that antioxidant enzymes in rat cardiac tissue can be significantly induced by phenolic acids following oral administration.
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PMID:Inducing gene expression of cardiac antioxidant enzymes by dietary phenolic acids in rats. 1854 98

The zinc-binding protein metallothionein-III (MT-III) is associated with resistance to neuronal injury. However, the underlying mechanism for its effects is unclear. In this study, we demonstrate that MT-III prevents the accumulation of reactive oxygen species (ROS) in dopaminergic SH-SY5Y cells challenged with the Parkinson's disease-related neurotoxin 6-hydroxydopamine (6-OHDA) by a mechanism that involves phosphatidylinositol 3-kinase (PI3K) and ERK kinase/NF-E2-related factor 2 (Nrf2) dependent induction of the stress response protein heme oxygenase-1 (HO-1). Pretreatment of SH-SY5Y cells with MT-III significantly reduced 6-OHDA-induced generation of ROS, caspase-3 activation, and subsequent cell death. Also, MT-III up-regulates HO-1 expression and this expression confers neuroprotection against oxidative injury induced by 6-OHDA. Moreover, MT-III induces Nrf2 nuclear translocation, which is upstream of MT-III-induced HO-1 expression, and PI3K and ERK1/2 activation, a pathway that is involved in induced Nrf2 nuclear translocation, HO-1 expression and neuroprotection. Taken together, these results suggest that the PI3K and ERK/Nrf2 signaling pathway controls the intracellular levels of ROS by regulating the expression of the antioxidant enzyme HO-1.
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PMID:Metallothionein-III protects against 6-hydroxydopamine-induced oxidative stress by increasing expression of heme oxygenase-1 in a PI3K and ERK/Nrf2-dependent manner. 1855 77

The peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a regulator of anti-inflammatory genes. One of its agonists, rosiglitazone-widely used in the treatment of type 2 diabetes mellitus-has recently been reported to increase the risk for myocardial infarction. In contrast, various studies provide evidence for a rosiglitazone-induced cardioprotection in different models of acute myocardial I/R. Here, we report that this protection can still be observed after 28 days of reperfusion in a murine model even when treatment commenced after the period of ischemia (reperfusion therapy). In vitro, cells from the rat cardiomyoblast cell line H9c2(2-1) are protected against oxidative stress by incubation with rosiglitazone, which can be abrogated by dexamethasone or cycloheximide. The antioxidant enzyme heme oxygenase 1 is up-regulated in these cells after rosiglitazone treatment. Our data provide further evidence that rosiglitazone exerts protective effects during myocardial I/R and might contribute to the reevaluation of the approved drug rosiglitazone.
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PMID:Rosiglitazone is cardioprotective in a murine model of myocardial I/R. 1856 25


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