scholarly journals Accumulation of manganese superoxide dismutase under metal-depleted conditions: proposed role for zinc ions in cellular redox balance

2004 ◽  
Vol 377 (1) ◽  
pp. 241-248 ◽  
Author(s):  
Kaoru OTSU ◽  
Yoshitaka IKEDA ◽  
Junichi FUJII
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Dna Binding ◽  
Manganese Superoxide Dismutase ◽  
Binding Activity ◽  
Rat Liver Mitochondria ◽  
Zinc Ions ◽  
Dna Binding Activity ◽  
Manganese Superoxide ◽  
In Cells

A diet low in copper results in increased levels of MnSOD (manganese superoxide dismutase), a critical antioxidative enzyme conferring protection against oxidative stress, in rat liver mitochondria. The mechanism for this was investigated using cultured HepG2 cells, a human hepatocellular carcinoma-derived line. MnSOD activity increased 5–7-fold during incubation in a medium supplemented with metal-depleted fetal bovine serum, with a corresponding elevation of its mRNA levels. Metal depletion also decreased CuZnSOD and glutathione peroxidase levels to approx. 70–80% of baseline. When zinc ions were added to the medium at micromolar levels, MnSOD accumulation was suppressed; however, copper ions had essentially no effect on MnSOD expression. Since the intracellular redox status was shifted to a more oxidized state by metal depletion, we examined the DNA-binding activity of NF-κB (nuclear factor-κB), an oxidative stress-sensitive transactivating factor that plays a primary role in MnSOD induction. A gel shift assay indicated that the DNA-binding activity of NF-κB was increased in cells maintained in metal-depleted culture, suggesting the involvement of the transactivating function of NF-κB in this induction. This was further supported by the observation that curcumin suppressed both the DNA-binding activity of NF-κB and the induction of MnSOD mRNA in cells cultivated under metal-depleted conditions. These results suggest that the level of zinc, rather than copper, is a critical regulatory factor in MnSOD expression. It is possible that a deficiency of zinc in the low-copper diet may be primarily involved in MnSOD induction.

Abstract 357: Manganese Superoxide Dismutase: a Novel Mediator of Heart Failure Development and Progression

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Sumitra Miriyala ◽  
Mini Chandra ◽  
Benjamin Maxey ◽  
Daret K St. Clair ◽  
Manikandan Panchatcharam
Keyword(s):  
Superoxide Dismutase ◽  
Oxygen Consumption ◽  
Manganese Superoxide Dismutase ◽  
Consumption Rate ◽  
Primary Source ◽  
Wild Type ◽  
Membrane Pore ◽  
Manganese Superoxide ◽  
Rate Of Oxygen Consumption ◽  
In Cells

Manganese Superoxide Dismutase (MnSOD), an antioxidant enzyme that catalyzes the conversion of superoxide radicals (O 2 •-) in mitochondria. Constitutive activation mitochondrial reactive oxygen species (ROS) has been implicated in both the pathogenesis and the progression of cardiovascular disease. Absence of SOD2 (gene that encodes MnSOD) is found to be embryonic lethal in animal models due to impairment of mitochondrial function, most noticeably in the heart. In our earlier investigation, we have shown that the MnSOD mimetic, MnTnBuOE-2-PyP 5+ distributes 3-fold more in mitochondria than in cytosol. The exceptional ability of MnTnBuOE-2-PyP 5+ to dismute O 2 •- parallels its ability to reduce ONOO– and CO3–. Based on our earlier reports, we have generated mice that specifically lack MnSOD in cardiomyocytes (Mhy6-SOD2 Δ ). These mice showed early mortality ~4 months due to cardiac mitochondrial dysfunction. Oxidative phosphorylation (OXPHOS) in mitochondria is the predominant mode for O 2 consumption in cells, and the mitochondria are the primary source of ROS in cells due to leaked electrons. FACS analyses using Mito-Tracker Green indicated that the mass of mitochondria per cell was slightly decreased in the Mhy6-SOD2 Δ to the wild type. We then examined OXPHOS levels in Mhy6-SOD2 Δ v.s. wild type using a Seahorse XF analyzer. The rate of oxygen consumption per cells was signi[[Unable to Display Character: fi]]cantly lower in Mhy6-SOD2 Δ cardiomyocytes than that in wild type. The most noticeable difference in the O 2 consumption was found in the presence of FCCP (H+ ionophore / uncoupler). FCCP is an inner membrane pore opener which resets the proton gradient between the mitochondrial matrix and the interspace, resulting in continuous transport of protons and consuming O 2 at the maximum potential. Remarkably, while the FCCP treatment increased O 2 consumption in wild type, the treatment showed no effect on the O 2 consumption in the Mhy6-SOD2 Δ cardiomyocytes. The result indicated that the low basal OXPHOS activity in Mhy6-SOD2 Δ was due to unusually low OXPHOS potential. We examined glycolysis in these cells by measuring extracellular acidi[[Unable to Display Character: fi]]cation (ECAR) and the pattern exactly opposite to that of oxygen consumption rate (OCR) was observed for glycolysis rates between Mhy6-SOD2 Δ and wild type.

Enhanced DNA-binding activity of a Stat3-related protein in cells transformed by the Src oncoprotein

Science ◽  
1995 ◽  
Vol 269 (5220) ◽  
pp. 81-83 ◽  
Author(s):  
C. Yu ◽  
D. Meyer ◽  
G. Campbell ◽  
A. Larner ◽  
C Carter-Su ◽  
...  
Keyword(s):  
Dna Binding ◽  
Binding Activity ◽  
Related Protein ◽  
Dna Binding Activity ◽  
In Cells

Calorie restriction attenuates inflammatory responses to myocardial ischemia-reperfusion injury

2001 ◽  
Vol 280 (5) ◽  
pp. H2094-H2102 ◽  
Author(s):  
B. Chandrasekar ◽  
J. F. Nelson ◽  
J. T. Colston ◽  
G. L. Freeman
Keyword(s):  
Oxidative Stress ◽  
Dna Binding ◽  
Antioxidant Enzyme ◽  
Calorie Restriction ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Myocardial Oxidative Stress

The life-prolonging effects of calorie restriction (CR) may be due to reduced damage from cumulative oxidative stress. Our goal was to determine the long-term effects of moderate dietary CR on the myocardial response to reperfusion after a single episode of sublethal ischemia. Male Fisher 344 rats were fed either an ad libitum (AL) or CR (40% less calories) diet. At age 12 mo the animals were anaesthetized and subjected to thoracotomy and a 15-min left-anterior descending coronary artery occlusion. The hearts were reperfused for various periods. GSH and GSSG levels, nuclear factor-κB (NF-κB) DNA binding activity, cytokine, and antioxidant enzyme expression were assessed in the ischemic zones. Sham-operated animals served as controls. Compared with the AL diet, chronic CR limited oxidative stress as seen by rapid recovery in GSH levels in previously ischemic myocardium. CR reduced DNA binding activity of NF-κB. The κB-responsive cytokines interleukin-1β and tumor necrosis factor-α were transiently expressed in the CR group but persisted longer in the AL group. Furthermore, expression of manganese superoxide dismutase, a key antioxidant enzyme, was significantly delayed in the AL group. Collectively these data indicate that CR significantly attenuates myocardial oxidative stress and the postischemic inflammatory response.

scholarly journals Role of reduced manganese superoxide dismutase in ischemia-reperfusion injury: a possible trigger for autophagy and mitochondrial biogenesis?

2013 ◽  
Vol 304 (3) ◽  
pp. F257-F267 ◽  
Author(s):  
Nirmala Parajuli ◽  
Lee Ann MacMillan-Crow
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Renal Function ◽  
Mitochondrial Biogenesis ◽  
Renal Damage ◽  
Manganese Superoxide Dismutase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Manganese Superoxide ◽  
Oxidant Production

Excessive generation of superoxide and mitochondrial dysfunction has been described as being important events during ischemia-reperfusion (I/R) injury. Our laboratory has demonstrated that manganese superoxide dismutase (MnSOD), a major mitochondrial antioxidant that eliminates superoxide, is inactivated during renal transplantation and renal I/R and precedes development of renal failure. We hypothesized that MnSOD knockdown in the kidney augments renal damage during renal I/R. Using newly characterized kidney-specific MnSOD knockout (KO) mice the extent of renal damage and oxidant production after I/R was evaluated. These KO mice (without I/R) exhibited low expression and activity of MnSOD in the distal nephrons, had altered renal morphology, increased oxidant production, but surprisingly showed no alteration in renal function. After I/R the MnSOD KO mice showed similar levels of injury to the distal nephrons when compared with wild-type mice. Moreover, renal function, MnSOD activity, and tubular cell death were not significantly altered between the two genotypes after I/R. Interestingly, MnSOD KO alone increased autophagosome formation, mitochondrial biogenesis, and DNA replication/repair within the distal nephrons. These findings suggest that the chronic oxidative stress as a result of MnSOD knockdown induced multiple coordinated cell survival signals including autophagy and mitochondrial biogenesis, which protected the kidney against the acute oxidative stress following I/R.

scholarly journals Redox Regulation of Adenovirus-Induced AP-1 Activation by Overexpression of Manganese-Containing Superoxide Dismutase

2002 ◽  
Vol 76 (1) ◽  
pp. 355-363 ◽  
Author(s):  
Hannah J. Zhang ◽  
Victoria J. Drake ◽  
Linjing Xu ◽  
Jianfang Hu ◽  
Frederick E. Domann ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Dna Binding ◽  
Redox Regulation ◽  
Recombinant Adenovirus ◽  
Redox Status ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Promising Tool ◽  
Gel Shift Assay ◽  
Intracellular Redox Status

ABSTRACT Adenovirus gene therapy is a promising tool in the clinical treatment of many genetic and acquired diseases. However, it has also caused pathogenic effects in organs such as the liver. The redox-sensitive transcription factors AP-1 and NF-κB have been implicated in these effects. To study the mechanisms of adenovirus-mediated AP-1 and NF-κB activation and the possible involvement of oxidative stress in adenovirus transduction, rats were injected with either replication-defective recombinant adenovirus with DNA containing the cytomegalovirus promoter region only (AdCMV), adenovirus containing human manganese-containing superoxide dismutase (MnSOD) cDNA (AdMnSOD), or vehicle. Compared to vehicle and AdCMV transduction, MnSOD gene transfer yielded a fivefold increase in liver MnSOD activity 7 days postinjection. Gel shift assay showed that AdCMV transduction induced DNA binding activity for AP-1 but not NF-κB. MnSOD overexpression abolished this activation. Western blotting analysis of c-Fos and c-Jun suggested that up-regulation of c-fos and c-jun gene expression does not directly contribute to the induction of AP-1 activation. Glutathione/glutathione disulfide ratios were decreased by adenovirus transduction and restored by MnSOD overexpression. The AP-1 binding activity that was induced by AdCMV was decreased by immunoprecipitation of Ref-1 protein. Ref-1 involvement was confirmed by restoration of AP-1 binding activity after the immunoprecipitated Ref-1 protein had been added back. AP-1 DNA binding activity was also elevated in control and AdMnSOD-injected rats after addition of the immunoprecipitated Ref-1 protein. These data indicate that cellular transduction by recombinant adenovirus stimulates AP-1 DNA binding activity. Furthermore, our results suggest that MnSOD overexpression decreases AP-1 DNA binding activity by regulating intracellular redox status, with the possible involvement of Ref-1 in this redox-sensitive pathway.

Sign in / Sign up

Export Citation Format

Share Document