Effect Of Manganese Superoxide Dismutase Research Articles

The protective effect of manganese superoxide dismutase from thermophilic bacterium HB27 on hydrochloric acid-induced chemical cystitis in rats

PurposeTo evaluate the effects of manganese superoxide dismutase (Mn-SOD) from thermophilic bacterium HB27 (name as Tt-SOD) on chemical cystitis.MethodsControl and experimental rats were infused by intravesical saline or hydrochloric acid (HCl) on the first day of the experiments. Saline, sodium hyaluronate (SH) or Tt-SOD were infused intravesically once a day for three consequent days. On the fifth day, the rats were weighted and sacrificed following a pain threshold test. The bladder was harvested for histological and biochemical analyses.ResultsTt-SOD could reduce the bladder index, infiltration of inflammatory cells in tissues, serum inflammatory factors and SOD levels, mRNA expression of inflammatory factors in tissues, and increase perineal mechanical pain threshold and serum MDA and ROS levels in HCl-induced chemical cystitis. Furthermore, Tt-SOD alleviated inflammation and oxidative stress by the negative regulation of the NF-κB p65 and p38 MAPK signaling pathway.ConclusionsIntravesical instillation of Tt-SOD provides protective effects against HCl-induced cystitis.

A role for Snail-MnSOD axis in regulating epithelial-to-mesenchymal transition markers expression in RPE cells

Age-related macular degeneration (AMD) is a common cause of vision loss. The epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells, accompanied by oxidative damage, plays a crucial role in AMD. It is well known that manganese superoxide dismutase (MnSOD) encoded by SOD2 is a critical molecule in fighting against oxidative stress, and Snail encoded by SNAI1 is the essential transcription factor for EMT. However, the effect of MnSOD on EMT and the underlying mechanism in RPE cells remains unknown. In this study, we found that MnSOD knockdown triggered the EMT by upregulating Snail, while MnSOD overexpression reversed EMT even with TGFβ treatment in RPE cells, and the anti-oxidative stress activity of MnSOD mediated this observation. In addition, Snail depletion increased both expression and activity of MnSOD while Snail overexpression decreased MnSOD expression and activity, and Dual-luciferase reporter and ChIP assays showed that Snail directly bound to E-box (CACCTG) in the SOD2 promoter. Moreover, MnSOD over-expression and Snail interference co-treatment strengthened the anti-oxidation and EMT reversing. Therefore, our findings demonstrate that MnSOD prevents EMT of RPE cells in AMD through inhibiting oxidative injury to RPE. Moreover, a critical EMT transcription factor, Snail, functions as a new negative transcriptional factor of SOD2. Herein, the Snail-MnSOD axis forms a mutual loop in the development of AMD, which may be a novel systemic treatment target for preventing AMD.

Manganese superoxide dismutase deficiency exacerbates the mitochondrial ROS production and oxidative damage in Chagas disease

In this study, we have investigated the effects of manganese superoxide dismutase (SOD2 or MnSOD) deficiency on mitochondrial function and oxidative stress during Chagas disease. For this, C57BL/6 wild type (WT) and MnSOD+/- mice were infected with Trypanosoma cruzi (Tc), and evaluated at 150 days’ post-infection that corresponded to chronic disease phase. Genetic deletion of SOD2 decreased the expression and activity of MnSOD, but it had no effect on the expression of other members of the SOD family. The myocardial expression and activity of MnSOD were significantly decreased in chronically infected WT mice, and it was further worsened in MnSOD+/- mice. Chronic T. cruzi infection led to a decline in mitochondrial complex I and complex II driven, ADP-coupled respiration and ATP synthesis in the myocardium of WT mice. The baseline oxidative phosphorylation (OXPHOS) capacity in MnSOD+/- mice was decreased, and it had an additive effect on mitochondrial dysregulation of ATP synthesis capacity in chagasic myocardium. Further, MnSOD deficiency exacerbated the mitochondrial rate of reactive oxygen species (ROS) production and myocardial oxidative stress (H2O2, protein carbonyls, malondialdehyde, and 4-hydroxynonenal) in Chagas disease. Peripheral and myocardial parasite burden and inflammatory response (myeloperoxidase, IL-6, lactate dehydrogenase, inflammatory infiltrate) were increased in all chagasic WT and MnSOD+/- mice. We conclude that MnSOD deficiency exacerbates the loss in mitochondrial function and OXPHOS capacity and enhances the myocardial oxidative damage in chagasic cardiomyopathy. Mitochondria targeted, small molecule mitigators of MnSOD deficiency will offer potential benefits in averting the mitochondrial dysfunction and chronic oxidative stress in Chagas disease.

Effects of MnSOD silence on in vitro tumorigenicity in NCI-H446 cells

To investigate the effect of manganese superoxide dismutase (MnSOD) silence on the in vitro tumorigenicity in human small cell lung cancer NCI-H446 cells and the underlying mechanisms. Methods: Sphere formation cells from NCI-H446 cells were obtained by suspension culture, while the expression of MnSOD and urokinase type plasminogen activator (uPAR) was analyzed by Western blot. Silence of MnSOD was performed by adenovirus infection in the second passage formation cells, and the effect of MnSOD silence on tumorigenicity in NCI-H446 cells was evaluated by sphere formation assay and soft-agar colony formation assay, while the expression of uPAR was analyzed by Western blot. Results: Compared with NCI-H446 cells, the sphere formation rate, colony formation rate, and the expression of MnSOD and uPAR were significantly increased in the second passage sphere formation cells in NCI-H446 cells (P<0.05). Silence of MnSOD inhibited the sphere formation rate, colony formation rate, and the expression level of uPAR in the second passage sphere formation cells in NCI-H446 cells. Conclusion: MnSOD may promote tumorigenicity in NCI-H446 cells by up-regulation of uPAR expression in vitro.

Manganese Superoxide Dismutase Gene-Modified Mesenchymal Stem Cells Attenuate Acute Radiation-Induced Lung Injury.

Radiation-induced lung injury (RILI) is a major clinical complication for radiotherapy in thoracic tumors. An immediate effect of lung irradiation is the generation of reactive oxygen that can produce oxidative damage to DNA, lipids, and proteins resulting in lung cell injury or death. Currently, the medical management of RILI remains supportive. Therefore, there is an urgent need for the development of countermeasures. The present study aimed to evaluate the protective effect of manganese superoxide dismutase (MnSOD) gene-modified mesenchymal stem cells (MSCs) to facilitate the improved recovery of RILI. Here, nonobese diabetic/severe combined immunodeficiency mice received a 13 Gy dose of whole-thorax irradiation, and were then transfused intravenously with MnSOD-MSCs and monitored for 30 days. Lung histopathologic analysis, plasma levels of inflammatory cytokines (interleukin [IL]-1, IL-6, IL-10, and tumor necrosis factor-α), profibrotic factor transforming growth factor-β1, and the oxidative stress factor (hydroxyproline) were evaluated after MnSOD-MSC transplant. Apoptotic rates were evaluated by terminal deoxynucleotidyl transferase-mediated nick-end labeling immunohistochemical method. Colonization and differentiation of MnSOD-MSCs in the irradiated lung were analyzed by immunofluorescence staining. Consequently, systemic administration of MnSOD-MSCs significantly attenuated lung inflammation, ameliorated lung damage, and protected the lung cells from apoptosis. MnSOD-MSCs could differentiate into epithelial-like cells in vivo. MnSOD-MSCs were effective in modulating RILI in mice and had great potential for accelerating from bench to bedside.

Effects of manganese superoxide dismutase (MnSOD) expression on regulation of esophageal cancer cell growth and apoptosis in vitro and in nude mice

Manganese superoxide dismutase (MnSOD) catalyzes superoxide radical (O2 (-)) into hydrogen peroxide (H2O2), which is further catalyzed by the combined action of glutathione peroxidase (GPx) and catalase (CAT) into water and oxygen. MnSOD plays a role in cell protection from superoxide damage. This study aimed to investigate the effects of MnSOD on regulation of esophageal squamous cell carcinoma cell growth, apoptosis, and cell cycle distribution in vitro and tumor formation and growth in nude mouse xenografts. The data showed that differential levels of MnSOD expression had different effects on tumor cell proliferation, apoptosis, plating efficiency (PE), and cell cycle distribution in vitro and tumor formation and growth in nude mice. In particular, high levels of MnSOD expression promoted TE-1 cell growth and PE rate in vitro and in nude mice, whereas moderate MnSOD expression suppressed tumor cell growth and PE rate but induced more cell apoptosis. Thus, these data demonstrated the dual effects of MnSOD protein in esophageal squamous cell carcinoma and further study will confirm these current data.

Effects of antioxidant gene therapy on retinal neurons and oxidative stress in a model of retinal ischemia/reperfusion

Retinal ischemia/reperfusion (I/R) results in neuronal death and generation of reactive oxygen species. The aim of this study was to investigate the neuroprotective effect of manganese superoxide dismutase (SOD2) on retinal ganglion cells (RGCs) in an I/R-induced retinal injury model. One eye of each Wistar rat was pretreated with recombinant adeno-associated virus containing the SOD2 gene (AAV-SOD2) or recombinant AAV containing the GFP gene (AAV-GFP) by intravitreal injection 21days before initiation of I/R injury. Retinal I/R injury was induced by elevating intraocular pressure for 1h, and reperfusion was established immediately afterward. The number of RGCs and the inner plexiform layer (IPL) thickness were measured by Fluorogold retrograde labeling and hematoxylin and eosin staining at 6h, 24h, 72h, and 5days after injury. Superoxide anion, the number of RGCs, IPL thickness, malondialdehyde (MDA) level, 8-hydroxy-2-deoxyguanosine (8-OHdG) level, MnSOD (manganese superoxide dismutase) activity, and nitrotyrosine level were measured by fluorescence staining, immunohistochemistry, and enzyme-linked immunosorbent analysis at 5days after I/R injury. Severe RGC loss, reduced IPL thickness, reduced MnSOD activity, and increased superoxide ion, MDA, 8-OHdG, and nitrotyrosine production were observed after I/R injury. Administration of AAV-SOD2 significantly reduced the levels of superoxide ion, MDA, 8-OHdG, and nitrotyrosine and prevented the damage to RGCs and IPL. Delivery of the antioxidant gene inhibited I/R-induced RGC and IPL damage by reducing oxidative stress and nitrative stress, suggesting that MnSOD may be relevant for the neuroprotection of the inner retina from I/R-related diseases.

Elevated risk of hypertension induced by arsenic exposure in Taiwanese rural residents: possible effects of manganese superoxide dismutase (MnSOD) and 8-oxoguanine DNA glycosylase (OGG1) genes

Heavy metals, including arsenic and lead, may lead to cellular oxidative damage that is linked to hypertension. Manganese superoxide dismutase (MnSOD) is a scavenger of reactive oxygen species, and 8-oxoguanine DNA glycosylase (OGG1) is the major glycosylase that repairs DNA lesions. Interestingly, whether there is an elevated risk of hypertension with arsenic or lead exposure in individuals with genetic variations in MnSOD or OGG1 has not yet been investigated. Questionnaires were administered to 240 Taiwanese rural residents. Blood pressure and biochemical indicators were assessed in each subject. Urinary levels of arsenic and lead were measured with atomic absorption spectrometry; and MnSOD and OGG1 genotypes were identified via polymerase chain reaction. There was a dose-response relationship between urinary arsenic levels and risk of hypertension (P = 0.021, test for trend). However, there was no association between urinary lead levels and hypertension risk. Individuals with high urinary arsenic levels and the MnSOD Val-Ala/Ala-Ala genotypes had a greater risk of hypertension than those with low urinary arsenic levels and the MnSOD Val-Val genotype (odds ratio [OR] = 4.2, 95% confidence interval [CI] = 1.7-10.3). Subjects with a high urinary arsenic level and the OGG1 Cys-Cys genotype also had a greater risk of hypertension than those with a low urinary arsenic level and the OGG1 Ser-Ser/Ser-Cys genotypes (OR = 3.4, 95% CI = 1.1-10.7). Thus, both MnSOD and OGG1 genotypes may be prone to an increased risk of hypertension associated with arsenic exposure.

Modulation of in utero total body irradiation induced newborn mouse growth retardation by maternal manganese superoxide dismutase-plasmid liposome (MnSOD-PL) gene therapy

To determine the effects of Manganese superoxide dismutase (MnSOD) plasmid liposome (PL) maternal radioprotection on fetal mice, timed pregnant female mice (E14 gestation) were irradiated to 3.0 Gy total body irradiation (TBI) dose, and the number, weight, and growth and development over 6 months after birth of newborn mice was quantitated compared to irradiated controls. Maternal MnSOD-PL treatment at E13 improved pup survival at birth (5.4 ± 0.9/litter compared to irradiated 3.0 Gy controls 4.9 ± 1.1. There was no statistically significant difference in newborn abnormalities, male to female ratio in newborn litters, or other evidence of teratogenesis in surviving newborn mice from MnSOD-PL treated compared to irradiated controls. However, E13 3Gy irradiated pups from gene therapy treated mothers showed a significant increase in both growth and overall survival over 6 months after birth (p = 0.0022).To determine if transgene product crossed the placenta pregnant E13 mice were injected I.V. with hemagglutinin-epitope-tagged MnSOD (100 μgm plasmid in 100 μl liposomes), then 24 hours later fetal mice, placentas, and maternal tissues were removed and tested by both immunohistochemistry and RTPCR for transgene and product. There was no evidence of transgene or product in placenta or any fetal tissue while maternal liver was positive by both assays. The data provide evidence for fetal radioprotection by maternal MnSOD-PL gene therapy before irradiation which is mediated by an indirect bystander effect and is associated with a significant improvement in both survival at birth and growth and development of newborn mice.

Abstract 965: Mechanistic studies of a dietary combination in cancer prevention: The effects of manganese superoxide dismutase on tumor suppressor gene activation

Abstract Mechanistic Studies of a Dietary Combination in Cancer Prevention: The Effects of MnSOD on Tumor Suppressor Gene Activation Reactive oxygen species can act as signaling transduction molecules modulating various pathways, such as the PI3K/Akt pathway. It is known that this pathway is constitutively activated in tumorigenesis contributing to protein synthesis, cell cycle progression, migration and survival. However, the PI3K/Akt pathway is negatively regulated by the major tumor suppressor protein PTEN. PTEN has dual specificity phosphatase activity regulating Akt phosphorylation as a lipid phosphatase; as well as, regulating cyclin D1 expression as a protein phosphotase. However, these are the roles of cytoplasmic PTEN. Recently, the nuclear roles of PTEN have received significant attention. Nuclear PTEN plays a major role in maintaining cellular homeostasis and stability by contributing to chromosome stability, DNA repair and cell cycle arrest. Previous studies have shown that PTEN nuclear localization is mediated by oxidative stress and may play a role in p53 stabilization. Nevertheless, MnSOD is considered to be a novel tumor suppressor gene. MnSOD has been defined as a nuclear encoded primary antioxidant enzyme localized in the mitochondria. We have shown in previous studies that the dietary combination Protandim reduced tumor incidence and multiplicity via the synergistic induction of superoxide dismutase enzymes. It has been shown that overexpression of MnSOD in in vivo models can suppress tumor formation via modulation of AP-1 binding. Therefore, it is imperative to look at how MnSOD may affect the process of apoptosis and the activation of tumor suppressor genes involved (i.e. PTEN and p53). Using our in vivo models (wildtype, MnSOD knockout, non-transgenic and MnSOD transgenic mice), we investigated how modulation of MnSOD expression may affect PTEN-mediated p53 stabilization, and how this contributes to chemoprevention. In addition, we explored how mutations in p53 may affect the PTEN-p53 interaction and its effects on tumor promotion via a gene transfection approach. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 965.

Protective signalling effect of manganese superoxide dismutase in hypoxia-reoxygenation of hepatocytes

This study investigates the mechanism by which MnSOD exerts its protective effect in hypoxia-reoxygenation (H/R) injury in hepatocytes. Following induction of H/R, MnSOD expression and activity levels increased and remained high for over 24 h. Hepatocytes silenced for MnSOD (siMnSOD) demonstrated increased susceptibility to H/R-induced apoptotic cell death and a lower capacity to generate mitochondrial reactive oxygen species. Microarray and real time PCR analysis of gene expression from siMnSOD cells revealed a number of down-regulated protective genes, including hemeoxygenase-1, glutamate-cysteine ligase and Nrf2, a master regulator of cellular adaptation to stress. Decreased Nrf2 protein expression and nuclear translocation were also confirmed in siMnSOD cells. siMnSOD cells showed low glutathione (GSH) content with no oxidation to GSSG, lower lipid peroxidation levels than their controls and lower mitochondrial membrane potential, which all were even more salient after H/R. Therefore, MnSOD appears to act as a signalling mediator for the activation of survival genes following H/R injury in hepatocytes.

Protective signalling effect of manganese superoxide dismutase in hypoxia-reoxygenation of hepatocytes

Protective signalling effect of manganese superoxide dismutase in hypoxia-reoxygenation of hepatocytes

Protective and determining factors for the overall lipid peroxidation in ultraviolet A1-irradiated fibroblasts: in vitro and in vivo investigations.

Lipid peroxidation (LPO) is one major effector mechanism by which ultraviolet (UV) A contributes to photoageing and the promotion of skin cancer. It is a fingerprint of photo-oxidative stress within the skin, and is initiated by several pathways, with different reactive oxygen species (ROS) and iron ions being involved. To elucidate factors involved in UVA1-induced LPO in human dermal fibroblasts and mouse dermis, and the role of antioxidant enzymes in protecting cells against LPO. Using a highly sensitive high-performance liquid chromatography procedure, we measured malondialdehyde (MDA), a specific metabolic tracer molecule for LPO, to determine the overall LPO produced by a given UVA1 dose in vitro and in vivo. By using the iron chelator desferrioxamine (DFO), the hydroxyl radical scavenger dimethylsulphoxide (DMSO) and fibroblasts that specifically overexpress single antioxidant enzymes, we further indirectly assessed the protective effect of manganese superoxide dismutase (MnSOD), catalase and phospholipid hydroperoxide glutathione peroxidase (PHGPx) as well as the relative importance of different ROS and the role of transitional iron for the total amount of LPO induced by a distinct UVA dose. UVA1 irradiation resulted in a time- and dose-dependent increase in MDA levels in vitro, and the in vitro results were shown to have in vivo relevance. Fibroblasts incubated with DFO or DMSO produced lower levels of MDA than controls, as did fibroblasts overexpressing MnSOD, catalase or PHGPx. The cellular iron pool and hydroxyl radicals were the most important determining factors for the total amount of MDA produced after a given UVA1 dose, and PHGPx overexpression had the greatest protective effect against LPO.

Detection of the content and activity of the transcription factor AP-1 in a multistage skin carcinogenesis model.

Investigation of transcription factor activity in animal tissue during the early stage of cancer development can be difficult because of a low number of affected cells in a background of a large number of normal cells. We have used a well-established multistage skin carcinogenesis model to study the effect of manganese superoxide dismutase on the activity of AP-1 during an early stage of mouse skin carcinogenesis. The DNA binding activity of AP-1 proteins to a concensus DNA regulatory binding element known as TRE (TPA Responsive Element) is used as an in vitro assay for AP-1 activity in the nucleus of skin cells. This activity is detected by electrophoretic mobility shift assay (EMSA) which is based on the ability of specific proteins to bind and retard the migration of radioactive labeled oligonucleotides on a native gel. The presence of a specific protein in the complex can be identified by adding to EMSA an antibody specific for that protein, which will result in supershift complexes on the gel. The presence of the proteins in question can be further verified by standard Western analysis of the nuclear proteins.

Effects of manganese superoxide dismutase, when given after inhalation injury has been established.

To determine whether treatment with manganese superoxide dismutase (MnSOD), given intravenously after inhalation injury has been established, improves oxygenation and lung fluid balance. Randomized, controlled intervention trial. University research laboratory. Twenty-four chronically instrumented awake ewes with lung lymph fistulas. After smoke inhalation with 48 breaths of cotton smoke, the animals were assigned randomly to a control group (n = 6) or a treatment group, receiving 1000 units of MnSOD/kg (n = 6), 3000 units of MnSOD/kg (n = 6), or 9000 units of MnSOD/kg (n = 6) intravenously 1 hr after smoke inhalation. Different from the other three groups, in the group that received 3000 units of MnSOD, cardiac output and Pao2/Fio2 ratio did not significantly decrease throughout the experimental period. Apart from higher oxygen consumption in the group receiving 3000 units of MnSOD 24 hrs after smoke inhalation (263 +/- 44 mL/min vs. 182 +/- 36 mL/min; p < 0.05), no significant differences between treatment groups and control group were observed. Treatment with MnSOD given after smoke inhalation seems to be less effective then pretreatment with MnSOD, which was reported in previous studies to reduce the degree of inhalation injury.

Mitochondrial catalase potentiates the antitumor effects of manganese superoxide dismutase: [formula omitted] Ana M. Rodriguez, Pauline. M. Carrico, James. A. Bennett and Kelvin J. A. Davies. Albany Medical College, Albany, NY 12208

Mitochondrial catalase potentiates the antitumor effects of manganese superoxide dismutase: [formula omitted] Ana M. Rodriguez, Pauline. M. Carrico, James. A. Bennett and Kelvin J. A. Davies. Albany Medical College, Albany, NY 12208

Overexpression of MnSOD Protects Against Myocardial Ischemia/reperfusion Injury in Transgenic Mice

Generation of free radicals upon reperfusion has been cited as one of the major causes of ischaemia/reperfusion injury. The following series of experiments was designed to study the effect of manganese superoxide dismutase (MnSOD) overexpression in transgenic mice on ischemia/reperfusion injury. A species of 1.4 kb human MnSOD mRNA was expressed, and a 325% increase in MnSOD activity was detected in the hearts of transgenic mice with no changes in the other antioxidant enzymes or heat shock proteins. Immunocytochemical study indicated an increased labeling of MnSOD mainly in the heart mitochondria of the transgenic mice. When these hearts were perfused as Langendorff preparations for 45 min after 35 min of global ischemia, the functional recovery of the hearts, expressed as heart rate×left ventricular developed pressure, was 52±4% in the transgenic hearts as compared to 31±4% in the non-transgenic hearts. This protection was accompanied by a significant decrease in lactate dehydrogenase release from the transgenic hearts. Overexpression of MnSOD limited the infarct sizein vivoin a left coronary artery ligation model. Our results demonstrate that overexpression of MnSOD renders the heart more resistant to ischemia/reperfusion injury.

Effects of manganese superoxide dismutase on lung fluid balance after smoke inhalation.

There is evidence of increased oxygen free radical activity after smoke inhalation with and without concomitant burn injury. We determined the effects of manganese superoxide dismutase (Mn SOD) on lung fluid balance as measured by lung microvascular permeability coefficient (sigma), filtration coefficient (Kf), and lymph flow. Merino breed ewes (n = 6/group) were surgically prepared. The SOD group (SOD) received Mn SOD (9,000 U/kg) as an intravenous bolus and was insufflated with smoke. The control group (CON) received saline and smoke. sigma and Kf were determined 24 h before and 24 h after smoke injury. Lymph flow, arterial O2-to-inspired O2 fraction ratio, systemic hemodynamics, and pulmonary arterial and capillary pressures were measured. The sigma was significantly (P < 0.05) higher after smoke insufflation in SOD compared with CON (0.71 +/- 0.03 vs. 0.53 +/- 0.05). Kf was significantly lower after smoke insufflation in SOD compared with CON (0.038 +/- 0.010 vs. 0.061 +/- 0.010). Lymph flows were significantly lower during the 24 h after smoke insufflation in SOD compared with CON (33 +/- 7 vs. 55 +/- 8 ml/h at 24 h). Arterial O2-to-inspired O2 fraction ratio was significantly improved at 6 and 12 h after smoke insufflation in SOD compared with CON at the same time points. Mn SOD meliorates the lung microvascular permeability changes associated with smoke inhalation injury.