UNIPROT:P04179 - FACTA Search

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Query: UNIPROT:P04179 (MnSOD)
2,777 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proinflammatory cytokines (interleukin-1beta [IL-1beta], tumor necrosis factor-alpha [TNF-alpha], and gamma-interferon [IFN-gamma]) initiate a variety of signal cascades in pancreatic beta-cells that affect the expression level of genes involved in both the destruction and the protection of the beta-cell. The generation of nitric oxide (NO) via the inducible NO synthase (iNOS) and oxygen free radicals play a key role in cytokine-mediated beta-cell destruction. Within these signal cascades, the activation of the transcription factor nuclear factor-kappaB (NF-kappaB) is crucial, and many cytokine-sensitive genes contain binding sites for this transcription factor in their promoter regions. The aim of this study was to characterize the cytokine-mediated activation of NF-kappaB and the subsequent expression of iNOS protein in insulin-producing RINm5F cells with an improved antioxidant defense status by overexpression of the cytoprotective enzymes catalase (Cat), glutathione peroxidase (Gpx), and the cytoplasmic Cu/Zn superoxide dismutase (Cu/ZnSOD). RINm5F cells with diverse mitochondrial antioxidative defense status were generated by stable overexpression of MnSOD constructs in sense (MnSOD sense) and antisense orientation (MnSOD antisense). Cytokine-induced (IL-1beta or cytokine mix consisting of IL-1beta + TNF-alpha + IFN-gamma) activation of NF-kappaB in RINm5F cells was reduced by >80% through overexpression of MnSOD. The activity of the iNOS promoter remained at basal levels in cytokine-stimulated MnSOD sense cells. In contrast, the suppression of MnSOD gene expression in cytokine-stimulated MnSOD antisense cells resulted in a threefold higher activation of NF-kappaB and a twofold higher activation of the iNOS promoter as compared with control cells. The iNOS protein expression was significantly reduced after a 6- and 8-h cytokine incubation of MnSOD sense cells. The low activity level of MnSOD in RINm5F MnSOD antisense cells increased the iNOS protein expression in particular during the early phase of cytokine-mediated toxicity. Cat, Gpx, and the cytoplasmic Cu/ZnSOD did not affect the activation of NF-kappaB and the iNOS promoter. In conclusion, the overexpression of MnSOD, which inactivates specifically mitochondrially derived oxygen free radicals, significantly reduced the activation of NF-kappaB in insulin-producing cells. As a consequence of this protective effect in the early cytokine signaling pathways, the induction of iNOS, an important event in the beta-cell destruction process, was also significantly reduced. The results provide evidence that mitochondrially derived reactive oxygen species (ROS) play a critical role in the activation of the cytokine-sensitive transcription factor NF-kappaB. Overexpression of MnSOD may thus be beneficial for beta-cell survival through suppression of oxygen free radical formation, prevention of NF-kappaB activation, and iNOS expression.
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PMID:Improvement of the mitochondrial antioxidant defense status prevents cytokine-induced nuclear factor-kappaB activation in insulin-producing cells. 1250 98

The markers of the bioavailability of NO (endothelium-dependent relaxation to acetylcholine and cyclic GMP content) in the thoracic aorta of apolipoprotein-E-deficient (ApoE KO) mice, 20 weeks old with enriched cholesterol diet or 35 weeks old on regular chow, are not decreased, in contrast with other models of atherosclerosis. However, severe hypercholesterolemia, the presence of atherosclerotic lesions and increased NADPH oxidase activity have been reported as early as at 20 weeks of age. The present experiments were designed to test if an increased capacity of NO production in these mice explains this paradox. The expressions of the 3 isoforms of NO synthase (NOS) were compared in ApoE KO and C57Bl/6J mice using Western blot and localized by immunohistochemistry. No adaptive increase in the expression of NOS was detected in ApoE KO mice. NO bioavailability could also be preserved by upregulation of enzymes involved in redox status such as CuZn or Mn superoxide dismutase and catalase. However, these enzymes were less expressed in ApoE KO mice than in control mice. These results highlight that ApoE KO mice represent an atypical model of atherosclerosis.
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PMID:Persistence of the nitric oxide pathway in the aorta of hypercholesterolemic apolipoprotein-E-deficient mice. 1280 44

We hypothesized that aging is characterized by a reduced release of nitric oxide (NO) in response to shear stress in resistance vessels. Mesenteric arterioles and arteries of young (6 mo) and aged (24 mo) male Fischer 344 rats were isolated and cannulated. Shear stress (15 dyn/cm(2))-induced dilation was significantly reduced and shear stress (1, 5, 10, and 15 dyn/cm(2))-induced increases in perfusate nitrite were significantly smaller at all shear stress levels in vessels of aged rats. Inhibition of NO synthesis abolished shear stress-induced release of nitrite. Furthermore, shear stress (15 dyn/cm(2))-induced release of nitrate was significantly higher and total nitrite (nitrite plus nitrate) was significantly lower in vessels of aged rats. Tiron or SOD significantly increased nitrite released from vessels of aged rats, but this was still significantly less than that in young rats. Superoxide production was increased and the activity of SOD was decreased in vessels of aged rats. There were no differences in endothelial NO synthase (eNOS) protein and basal activity or in Cu/Zn-SOD and Mn-SOD proteins in vessels of the two groups, but extracellular SOD was significantly reduced in vessels of aged rats. Maximal release of NO induced by shear stress plus ACh (10(-5) M) was comparable in the two groups, but phospho-eNOS in response to shear stress (15 dyn/cm(2)) was significantly reduced in vessels of aged rats. These data suggest that an increased production of superoxide, a reduced activity of SOD, and an impaired shear stress-induced activation of eNOS are the causes of the decreased shear stress-induced release of NO in vessels of aged rats.
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PMID:Reduced release of nitric oxide to shear stress in mesenteric arteries of aged rats. 1475 61

The early phase of preconditioning (PC) lasts 2 to 3 hours and protects against myocardial infarction, but not against stunning. In contrast, the late phase of PC lasts for 3 to 4 days and protects against both myocardial stunning and infarction, making this phenomenon more clinically relevant. Late PC is a genetic reprogramming of the heart that involves the activation of several stress-responsive genes, which ultimately results in the development of a cardioprotective phenotype. Sublethal ischemic insults release chemical signals (nitric oxide [NO], adenosine, and reactive oxygen species) that trigger a series of signaling events (eg, activation of protein kinase C, Src protein tyrosine kinases, Janus kinases 1/2, and nuclear factor-kappaB) and culminates in increased synthesis of inducible NO synthase, cyclooxygenase-2, heme oxygenase-1, aldose reductase, Mn superoxide dismutase, and probably other cardioprotective proteins. In addition to ischemia, heat stress, exercise, and cytokines can also induce a similar series of events. Perhaps most importantly, many pharmacologic agents (eg, NO donors, adenosine receptor agonists, endotoxin derivatives, or opioid receptor agonists) can mimic the effects of ischemia in inducing the late phase of PC, suggesting that this phenomenon might be exploited therapeutically. The purpose of this review is to summarize the mechanisms that underlie the late phase of ischemic PC.
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PMID:Delayed adaptation of the heart to stress: late preconditioning. 1545 41

Reactive oxygen species (ROS) and nitric oxide (NO) have a role in the development of pulmonary fibrosis after bleomycin administration. The ROS production induces an antioxidant response, involving superoxide dismutases (SODs), catalase, and glutathione peroxidases. We compared in situ oxidative burden and antioxidant enzyme activity in bleomycin-injured rat lungs and normal controls. ROS expression and catalase, glucose-6-phosphate-dehydrogenase (G6PHD), and NOS/NADPH-diaphorase activity were investigated by using histochemical reactions. Nitric oxide synthase (e-NOS and i-NOS) and SOD (MnSOD, Cu/ZnSOD, ECSOD) expression was investigated immunohistochemically. After treatment ROS production was enhanced in both phagocytes and in type II alveolar epithelial cells. Mn, Cu/Zn, and ECSOD were overexpressed in parenchymal cells, whereas interstitium expressed ECSOD. Catalase and G6PHD activity was moderately increased in parenchymal and inflammatory cells. NOS/NADPH-d activity and i-NOS expression increased in alveolar and bronchiolar epithelia and in inflammatory cells. It can be suggested that the concomitant activation of antioxidant enzymes is not adequate to scavenge the oxidant burden induced by bleomycin lung damage. Inflammatory cells and also epithelial cells are responsible of ROS and NO production. This oxidative and nitrosative stress may be a substantial trigger in TGF-beta1 overexpression by activated type II pneumocytes, leading to fibrotic lesions.
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PMID:In situ assessment of oxidant and nitrogenic stress in bleomycin pulmonary fibrosis. 1630 78

A common gene variant of human extracellular superoxide dismutase (ecSOD), in approximately 5% of humans, is associated with increased risk of ischemic heart disease. The purpose of this study was to examine vascular effects of ecSOD with effects of the ecSOD variant (ecSOD(R213G)) in rats with heart failure. Seven weeks after coronary artery ligation, we studied rats with heart failure and sham-operated rats. Adenoviral vectors expressing human ecSOD, ecSOD(R213G), or a control virus were injected intravenously. In the aorta from rats with heart failure, responses to acetylcholine (69 +/- 4% relaxation, means +/- SE) and basal levels of nitric oxide (NO) (vasoconstrictor responses to a NO synthase inhibitor) were greatly impaired, and levels of superoxide and peroxynitrite were increased. Gene transfer of ecSOD restored responses to acetylcholine (92 +/- 2% relaxation) and basal levels of NO to normal and reduced levels of superoxide [from 2.3 +/- 0.2 to 0.9 +/- 0.2 relative light units per second per millimeter squared (RLU x s(-1) x mm(-2))] and peroxynitrite (from 2.4 +/- 0.2 to 0.9 +/- 0.1 RLU x s(-1) x mm(-2)) in the aorta from rats with heart failure. Gene transfer of ecSOD(R213G) produced little or no improvement. Responses to nitroprusside were not different among the groups. Expression of endogenous mRNA for SODs (CuZnSOD, MnSOD, and ecSOD) and endothelial NOS in the aorta was not different among the groups. In contrast to ecSOD, gene transfer of ecSOD(R213G) in rats with heart failure has minimal beneficial effect on oxidative stress, endothelial function, or basal bioavailability of NO. We speculate that greatly diminished efficacy of ecSOD(R213G) in protection against oxidative stress and endothelial dysfunction may contribute to increased risk of cardiovascular disease in humans with ecSOD(R213G).
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PMID:Vascular effects of a common gene variant of extracellular superoxide dismutase in heart failure. 1684 Jul 38

We previously found that angiotensin II-induced hypertension increases vascular extracellular superoxide dismutase (ecSOD), and proposed that this is a compensatory mechanism that blunts the hypertensive response and preserves endothelium-dependent vasodilatation. To test this hypothesis, we studied ecSOD-deficient mice. ecSOD(-/-) and C57Blk/6 mice had similar blood pressure at baseline; however, the hypertension caused by angiotensin II was greater in ecSOD(-/-) compared with wild-type mice (168 versus 147 mm Hg, respectively; P<0.01). In keeping with this, angiotensin II increased superoxide and reduced endothelium-dependent vasodilatation in small mesenteric arterioles to a greater extent in ecSOD(-/-) than in wild-type mice. In contrast to these findings in resistance vessels, angiotensin II paradoxically improved endothelium-dependent vasodilatation, reduced intracellular and extracellular superoxide, and increased NO production in aortas of ecSOD(-/-) mice. Whereas aortic expression of endothelial NO synthase, Cu/ZnSOD, and MnSOD were not altered in ecSOD(-/-) mice, the activity of Cu/ZnSOD was increased by 80% after angiotensin II infusion. This was associated with a concomitant increase in expression of the copper chaperone for Cu/ZnSOD in the aorta but not in the mesenteric arteries. Moreover, the angiotensin II-induced increase in aortic reduced nicotinamide-adenine dinucleotide phosphate oxidase activity was diminished in ecSOD(-/-) mice as compared with controls. Thus, during angiotensin II infusion, ecSOD reduces hypertension, minimizes vascular superoxide production, and preserves endothelial function in resistance arterioles. We also identified novel compensatory mechanisms involving upregulation of copper chaperone for Cu/ZnSOD, increased Cu/ZnSOD activity, and decreased reduced nicotinamide-adenine dinucleotide phosphate oxidase activity in larger vessels. These compensatory mechanisms preserve large vessel function when ecSOD is absent in hypertension.
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PMID:Role of extracellular superoxide dismutase in hypertension. 1689 57

The renal and cardiac benefits of renin-angiotensin system (RAS) inhibition in hypertension exceed those attributable to blood pressure reduction, and seem to involve mitochondrial function changes. To investigate whether mitochondrial changes associated with RAS inhibition are related to changes in nitric oxide (NO) metabolism, four groups of male Wistar rats were treated during 2 wk with a RAS inhibitor, enalapril (10 mg x kg(-1) x day(-1); Enal), or a NO synthase (NOS) inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME) (1 mg x kg(-1) x day(-1)), or both (Enal+L-NAME), or were untreated (control). Blood pressure and body weight were lower in Enal than in control. Electron transfer through complexes I to III and cytochrome oxidase activity were significantly lower, and uncoupling protein-2 content was significantly higher in kidney mitochondria isolated from Enal than in those from control. All of these changes were prevented by L-NAME cotreatment and were accompanied by a higher production/bioavailability of kidney NO. L-NAME abolished mitochondrial NOS activity but failed to inhibit extra-mitochondrial kidney NOS, underscoring the relevance of mitochondrial NO in those effects of enalapril that were suppressed by L-NAME cotreatment. In Enal, kidney mitochondria H(2)O(2) production rate and MnSOD activity were significantly lower than in control, and these effects were not prevented by L-NAME cotreatment. These findings may clarify the role of NO in the interactions between RAS and mitochondrial metabolism and can help to unravel the mechanisms involved in renal protection by RAS inhibitors.
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PMID:Mitochondrial function and nitric oxide metabolism are modified by enalapril treatment in rat kidney. 1718 9

The naked mole rat (NMR; Heterocephalus glaber) is the longest-living rodent known [maximum lifespan potential (MLSP): >28 yr] and is a unique model of successful aging showing attenuated declines in most physiological function. This study addresses age-related changes in endothelial function and production of reactive oxygen species in NMR arteries and vessels of shorter-living Fischer 344 rats (MLSP: approximately 3 yr). Rats exhibit a significant age-dependent decline in acetylcholine-induced responses in carotid arteries over a 2-yr age range. In contrast, over a 10-yr age range nitric oxide (NO)-mediated relaxation responses to acetylcholine and to the NO donor S-nitrosopencillamine (SNAP) were unaltered in NMRs. Cellular superoxide anion (O(2)(*-)) and H(2)O(2) production significantly increased with age in rat arteries, whereas they did not change substantially with age in NMR vessels. Indicators of apoptotic cell death (DNA fragmentation rate, caspase 3/7 activity) were significantly enhanced ( approximately 250-300%) in arteries of 2-yr-old rats. In contrast, vessels from 12-yr-old NMRs exhibited only a approximately 50% increase in apoptotic cell death. In the hearts of NMRs (2 to 26 yr old), expression of endothelial NO synthase, antioxidant enzymes (Cu,Zn-SOD, Mn-SOD, catalase, and glutathione peroxidase), the NAD(P)H oxidase subunit gp91(phox), and mitochondrial proteins (COX-IV, ATP synthase, and porin, an indicator of mitochondrial mass) did not change significantly with age. Thus long-living NMRs can maintain a youthful vascular function and cellular oxidant-antioxidant phenotype relatively longer and are better protected against aging-induced oxidative stress than shorter-living rats.
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PMID:Vascular aging in the longest-living rodent, the naked mole rat. 1746 32

To clarify the mechanism underlying the antioxidant properties of l-carnitine (LC) and propionyl-l-carnitine (PLC) on spontaneously hypertensive (SHR) and normotensive WKY, animals were treated with either PLC or LC (200 mg kg(- 1)). Aorta was dissected and contraction to (R)-( - )-phenylephrine (Phe) and relaxation to carbachol (CCh) were assessed in the presence or not of the NO synthase (NOS) inhibitor, l-NAME. [image omitted] production was evaluated by lucigenin-enhanced chemiluminescence and its participation on relaxation was observed after incubation with superoxide dismutase (SOD) plus catalase. Protein expressions of eNOS, Cu/Zn-SOD and Mn-SOD were studied by western blot. Both LC and PLC treatments improved endothelial function of SHR through increasing NO participation and decreasing [image omitted] probably involving higher Cu/Zn-SOD expression. PLC treatment augmented eNOS expression in SHR. Surprisingly, LC increased [image omitted] produced by aorta from WKY and thus diminished NO and damaged endothelial function. Conversely, PLC did not affect CCh-induced relaxation in WKY. These results demonstrate that LC and PLC prevent endothelial dysfunction in SHR through an antioxidant effect.
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PMID:l-carnitine and its propionate: improvement of endothelial function in SHR through superoxide dismutase-dependent mechanisms. 1765 45

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