Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Manganese superoxide dismutase (MnSOD) is an antioxidant enzyme essential for the survival of life. We have reported that NF-kappaB is essential but not sufficient for the synergistic induction of MnSOD by phorbol 12-myristate 13-acetate and cytokines. To further identify transcription factors and co-activators that participate in the induction of MnSOD, we used NF-kappaB affinity chromatography to isolate potential NF-kappaB interacting proteins. Proteins eluted from the NF-kappaB affinity column were subjected to proteomic analysis and verified by Western analysis. Nucleophosmin (NPM), a nucleolar phosphoprotein, is the most abundant single protein identified. Co-immunoprecipitation studies suggest a physical interaction between NPM and NF-kappaB proteins. To verify the role of NPM on MnSOD gene transcription, cells were transfected with constructs expressing NPM in sense or antisense orientation as well as interference RNA. The results indicate that an increase NPM expression leads to increased MnSOD gene transcription in a dose-dependent manner. Consistent with this, expression of small interfering RNA for NPM leads to inhibition of MnSOD gene transcription but does not have any effect on the expression of interleukin-8, suggesting that the effect of NPM is selective. These results identify NPM as a partner of the NF-kappaB transcription complex in the induction of MnSOD by phorbol 12-myristate 13-acetate and cytokines.
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PMID:Identification of nucleophosmin as an NF-kappaB co-activator for the induction of the human SOD2 gene. 1508 54

Manganese superoxide dismutase (Mn-SOD) is a key antioxidant enzyme that prevents reactive oxygen species (ROS) damage to biological tissues. Although Mn-SOD has been investigated for a variety of cells, little is known about its expression in the tendon, particularly in the stress-deprived condition. The present study demonstrated that Mn-SOD is excessively expressed in the cultured fibroblasts derived from the stress-deprived patellar tendon in the rat using subtractive hybridization analysis. In addition, we confirmed that the expression of Mn-SOD is up-regulated in the stress-deprived patellar tendon in vivo at both the mRNA and protein levels. These results suggest that Mn-SOD may play a role in regulating ROS and matrix degradation involving mechanical deterioration of the stress-deprived tendon tissue.
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PMID:Stress deprivation enhances manganese superoxide dismutase expression in the rat patellar tendon. 1537 79

Autocrine pathways of proliferative and anti-apoptotic growth factors represent a serious impediment to the treatment of many types of tumors. In particular, interleukin-6 (IL-6), a pleiotropic cytokine known to play a critical role in the survival and growth of multiple myeloma cells, participates in an autocrine stimulation loop that serves to inhibit the induction of apoptosis during chemotherapy. Manganese superoxide dismutase (MnSOD) is an important antioxidant enzyme encoded by the SOD2 gene that attenuates oxidative free radicals in the mitochondria by catalyzing the formation of hydrogen peroxide from superoxide radicals. Transcription factor activity and binding is influenced by the oxidative state of cells, and dysregulation of MnSOD levels can result in abnormal patterns of gene expression. In the human multiple myeloma cell line IM-9, an autocrine IL-6 loop exists, which enables the cell to resist the effects of dexamethasone, a common treatment for multiple myeloma. Here, we show that SOD2 expression is epigenetically silenced in IM-9 cells, and replacement of MnSOD reduces cell proliferation and partially restores susceptibility to dexamethasone. The restoration of MnSOD also serves to decrease the expression levels of IL-6 by reducing the ability of activator protein-1, an important mediator of IL-6 expression in multiple myeloma cells, to bind to its enhancer site. These results show the importance of free radical-mediated dysregulation of autocrine growth factor loops in tumor cells and their effect on cell growth and response to chemotherapy.
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PMID:Enforced expression of superoxide dismutase 2/manganese superoxide dismutase disrupts autocrine interleukin-6 stimulation in human multiple myeloma cells and enhances dexamethasone-induced apoptosis. 1602 27

Manganese superoxide dismutase (MnSOD) is a primary antioxidant enzyme necessary for the survival of aerobic life. Previously, we demonstrated that specificity protein 1 (Sp1) is essential for the basal transcription of the MnSOD gene. We also identified nucleophosmin (NPM), an RNA-binding protein, as an important co-activator of NF-kappaB in the induction of MnSOD by cytokine and tumor promoter. Here, using chromatin immunoprecipitation (ChIP) analysis, we demonstrate that Sp1 and NPM interact in vivo to enhance NF-kappaB-mediated MnSOD induction. Interaction between NPM and Sp1 or NF-kappaB at the promoter and enhancer of the MnSOD gene in vivo were verified by the presence of the PCR products from the promoter and enhancer elements in the ChIP assay. Unexpectedly, we also found p53, another transcription factor, to be a component of the complex detected by ChIP assay. The presence of p53 in this transcription complex was verified by immunoprecipitation of p53 proteins with antibody to Sp1 in nuclear extracts. Using a vector expressing full-length p53 cDNA, we demonstrated that p53 overexpression suppresses MnSOD mRNA and protein levels. Consistent with the negative role of p53 in the expression of the MnSOD gene, expression of small interfering RNA for p53 leads to an increase of MnSOD mRNA and protein levels. Using ChIP assays and immunoprecipitation, we further demonstrated that p53 interacts with Sp1 to suppress both the constitutive and 12-O-tetradecanoylphorbol-13-acetate-stimulated expression of the MnSOD gene. Inhibition of the MnSOD gene by p53 was abolished when Sp1 sites on the MnSOD promoter were mutated or when the Sp1 protein was reduced by siRNA approaches. Because expression of MnSOD protects against cell death, our findings reveal a previously unrecognized mechanism of p53-mediated cell death and demonstrate an intricate relationship between the positive and negative control of MnSOD expression.
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PMID:Specificity protein 1-dependent p53-mediated suppression of human manganese superoxide dismutase gene expression. 1674 Jun 34

Manganese superoxide dismutase (MnSOD, SOD2) is an essential primary antioxidant enzyme which converts superoxide radical to hydrogen peroxide within the mitochondrial matrix. MnSOD plays a prominent role in protection against many apoptotic stimuli. Its absence may therefore impair the cellular redox balance and enhance apoptosis. Our data show that in Jurkat T cells, following oligomerization of the Fas receptor, MnSOD is selectively degraded during apoptosis. In the presence of cycloheximide, an inhibitor of protein synthesis, the rates of cell death and MnSOD degradation were accelerated. Fas-induced MnSOD cleavage was partially inhibited in the presence of the pan-caspase inhibitor, z-VAD-fmk. MnSOD in the mitochondrial fractions was cleaved in vitro by treatment with the cytosolic fraction of Fas-activated cells. Moreover, two possible cleavage sites of recombinant hMnSOD by direct interaction with recombinant caspase-3 were noted. Cellular and mitochondrial factors were found to be necessary for the interaction. These factors include intracellular mobilization of calcium. Our data indicate that inactivation of MnSOD in receptor-mediated apoptosis by caspase-specific degradation would render the mitochondria sensitive to the steady-state production of superoxide, decrease the steady-state flux of H(2)O(2), expedite the loss of mitochondrial function, and potentiate apoptosis.
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PMID:Manganese superoxide dismutase inactivation during Fas (CD95)-mediated apoptosis in Jurkat T cells. 1715 82

Manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant enzyme, is necessary for survival of aerobic life. Previously, we demonstrated that a Sp1-based promoter is essential for constitutive transcription and a NF-kappaB-based intronic enhancer is responsible for cytokine-mediated induction. Here we show that nucleophosmin (NPM), a RNA-binding protein, binds to an 11G single-stranded loop in the promoter region and serves to integrate the Sp1 and NF-kappaB responses. Disruption of the loop structure causes a reduction of both constitutive and inductive transcription due to loss of the binding motif for NPM. Interaction of NF-kappaB.NPM.Sp1 facilitated by binding of NPM to the loop structure in the promoter region appears to comprise the basic complex for the transcriptional stimulation. These results suggest a novel molecular mechanism for communication between the enhancer and the GC-rich promoter.
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PMID:The role of a single-stranded nucleotide loop in transcriptional regulation of the human sod2 gene. 1742 24

Manganese superoxide dismutase (MnSOD) is the only primary antioxidant enzyme in mitochondria that scavenges superoxide radicals. Overexpressing MnSOD in cancer cells by cDNA transfection suppresses tumor formation and reverses malignant growth. In this study, we examined the effect of recombinant human manganese superoxide dismutase (rhMnSOD) alone and in combination with adriamycin (ADR) against solid tumors of sarcoma 180 in Institute of Cancer Research (ICR) mice. Administration of rhMnSOD alone and in combination with ADR significantly inhibited tumor growth in a dose-dependent manner. The use of rhMnSOD in combination with ADR enhanced ADR's anti-tumor potency without increasing toxicity. Histopathological examination provided evidence of the anti-tumor effect. In addition, we found lymphocyte infiltration of the tumors, with an increase in both CD4- and CD8-positive cells in the treated tumors. The expression of CD4 and CD8 was up-regulated with increasing dose of rhMnSOD, and the combination treatment with ADR further enhanced this up-regulation. Collectively, these data indicate that rhMnSOD may exhibit an anti-tumor effect by stimulating the immune system and promoting the recruitment of lymphocytes into the tumor to kill tumor cells. Thus MnSOD may constitute a potential new therapeutic agent to be exploited as an adjuvant in cancer therapy.
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PMID:Enhanced anti-tumor effects achieved in a murine tumor model using combination therapy of recombinant human manganese superoxide dismutase and adriamycin. 1841 39

Ageing is an important risk factor for the development of cardiovascular diseases. Vascular ageing is mainly characterized by endothelial dysfunction, an alteration of endothelium-dependent signalling processes and vascular remodelling. The underlying mechanisms comprise increased production of reactive oxygen species (ROS), inactivation of nitric oxide (.NO) and subsequent formation of peroxynitrite (ONOO(-)). Elevated ONOO(-) may exhibit new messenger functions by post-translational oxidative modification of intracellular regulatory proteins. Mitochondria are a major source of age-associated superoxide formation, as electrons are misdirected from the respiratory chain. Manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant enzyme, is an integral part of the nucleoids and may protect mitochondrial DNA from ROS. A model linking .NO, mitochondria, MnSOD and its acetylation/deacetylation by sirtuins (NAD+-dependent class III histone deacetylases) may be the basis for a potentially new powerful therapeutic intervention in the ageing process.
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PMID:Signalling processes in endothelial ageing in relation to chronic oxidative stress and their potential therapeutic implications in humans. 1899 49

Cerebral ischemia and reperfusion increase superoxide anions (O(2)(*-)) in brain mitochondria. Manganese superoxide dismutase (Mn-SOD; SOD2), a primary mitochondrial antioxidant enzyme, scavenges superoxide radicals and its overexpression provides neuroprotection. However, the regulatory mechanism of Mn-SOD expression during cerebral ischemia and reperfusion is still unclear. In this study, we identified the signal transducer and activator of transcription 3 (STAT3) as a transcription factor of the mouse Mn-SOD gene, and elucidated the mechanism of O(2)(*-) overproduction after transient focal cerebral ischemia (tFCI). We found that Mn-SOD expression is significantly reduced by reperfusion in the cerebral ischemic brain. We also found that activated STAT3 is usually recruited into the mouse Mn-SOD promoter and upregulates transcription of the mouse Mn-SOD gene in the normal brain. However, at early postreperfusion periods after tFCI, STAT3 was rapidly downregulated, and its recruitment into the Mn-SOD promoter was completely blocked. In addition, transcriptional activity of the mouse Mn-SOD gene was significantly reduced by STAT3 inhibition in primary cortical neurons. Moreover, we found that STAT3 deactivated by reperfusion induces accumulation of O(2)(*-) in mitochondria. The loss of STAT3 activity induced neuronal cell death by reducing Mn-SOD expression. Using SOD2-/+ heterozygous knock-out mice, we found that Mn-SOD is a direct target of STAT3 in reperfusion-induced neuronal cell death. Our study demonstrates that STAT3 is a novel transcription factor of the mouse Mn-SOD gene and plays a crucial role as a neuroprotectant in regulating levels of reactive oxygen species in the mouse brain.
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PMID:Regulation of Mn-superoxide dismutase activity and neuroprotection by STAT3 in mice after cerebral ischemia. 1947 27

Manganese superoxide dismutase (Mn-SOD or SOD2) is a key antioxidant enzyme and was assigned several roles in tumor biology. Working on medulloblastoma cell line DAOY, we identified two spots as Mn-SODs. Because of the proposed pivotal role of this enzyme in oncobiology, we decided to completely sequence the proteins and to determine PTMs. Proteins extracted from DAOY cells were run on 2-DE, multienzyme digestions were carried out and peptides were analyzed by MALDI-TOF/TOF, Qq-TOF and the ion trap using both the CID and ETD principles. Both protein expression forms were completely sequenced and revealed identical protein sequences. Histidines His30 and His31 were oxidized in one protein, whereas tryptophan oxidation (Trp-186) was observed in both. Histidine oxidation was not only indicated by the mass shift of the peptide but also by specific spectra of 2-oxo-histidine and a previously described intermediate (His+14). Complete sequencing of the two Mn-SOD expression forms unambiguously characterizes this enzyme from a tumor cell line providing evidence that can be used for generation of antibodies and allowing conformational studies. The findings of different PTMs in the same gel represent Mn-SOD oxidative states, while oxidative modification of His30 and 31 may even reflect decreased Mn-SOD activity.
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PMID:Complete sequencing and oxidative modification of manganese superoxide dismutase in medulloblastoma cells. 1967 86


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