Overexpression Of CuZnSOD Research Articles

Cu-Zn SOD suppresses epilepsy in pilocarpine-treated rats and alters SCN2A/Nrf2/HO-1 expression

Copper-zinc superoxide dismutase (Cu-Zn SOD) is downregulated in epilepsy, however, the role of Cu-Zn SOD in epilepsy remains unclear. Based on the pilocarpine hydrochloride-induced rat model of epilepsy, cortical-striatum brain slices of rats were examined based on field excitatory post-synaptic potentials. Pathological changes were observed by transmission electron microscope. Also using SH-SY5Y cells, flow cytometry and TUNEL staining were applied to investigate cell apoptosis, and ELISA was applied to detect SOD activity. In addition, qRT-PCR and western blot were performed to detect SCN2A/Nrf2/HO-1 gene and protein expression levels, respectively. Cu-Zn SOD over-expression suppressed epilepsy in vivo. In addition, Cu-Zn SOD knockdown notably decreased SOD activity and induced apoptosis in SH-SY5Y cells. Moreover, Cu-Zn SOD silencing decreased the levels of SCN2A, Nrf2 and HO-1. Lastly, Cu-Zn SOD was shown to modulate the NaV1.2/Nrf2/HO-1 axis in rats. In this model, Cu-Zn SOD attenuated epilepsy and was shown to alter the expression level of proteins of the NaV1.2 /Nrf2/HO-1 signalling pathway, indicating that Cu-Zn SOD might be a target for the treatment of epilepsy.

Function of four mitochondrial genes in fumigation lethal mechanisms of Allyl Isothiocyanate against Sitophilus zeamais adults

Allyl isothiocyanate (AITC) is a promising alternative to chemical fumigants, and mitochondrial dysfunction has been proposed to play a crucial role in its lethal mechanisms; however, the specific lethal mechanisms of AITC remain unknown. Four mitochondrial electron transport chain genes, nd5, nd6, cox1, and cox5, were selected from adult Sitophilus zeamais and processed with RNA interference experiments. Then, the biochemical and biophysical effects were compared between double-stranded RNA (dsRNA)-mediated insects and wild-type insects after AITC fumigation at the concentration of LC50 values. The bioactivity of AITC against dsnd6-mediated insects increased, while the bioactivity against dcox1-mediated insects decreased. Compared with the wild-type insects, the increase of reactive oxygen species (ROS) levels by AITC in mitochondria from dsnd6-mediated insects increased by 18.95%, while that of dscox1-mediated insects decreased by 27.45%. The effects of AITC on mRNA expression levels of detoxifying enzymes including CAT (down-regulation effect) and CuZnSOD (overexpression effect) partly recovered in the dsnd5-mediated insects, while a greater effect was observed for dscox1-mediated insects. Molecular docking results indicated that ASN511 at the cox1 subunit was the binding site of AITC by one hydrogen bond, with a bond distance of 2.1 Å. These findings provide insight for further applications of AITC and could provide a novel strategy to investigate lethal mechanisms of insecticides.

Overexpression of Cu-Zn SOD in Brucella abortus suppresses bacterial intracellular replication via down-regulation of Sar1 activity.

Brucella Cu-Zn superoxide dismutase (Cu-Zn SOD) is a periplasmic protein, and immunization of mice with recombinant Cu-Zn SOD protein confers protection against Brucella abortus infection. However, the role of Cu-Zn SOD during the process of Brucella infection remains unknown. Here, we report that Cu-Zn SOD is secreted into culture medium and is translocated into host cells independent of type IV secretion systems (T4SS). Furthermore, co-immunoprecipitation and immunofluorescence studies reveal that Brucella abortus Cu-Zn SOD interacts with the small GTPase Sar1. Overexpression of Cu-Zn SOD in Brucella abortus inhibits bacterial intracellular growth by abolishing Sar1 activity in a manner independent of reactive oxygen species (ROS) production.

Overexpression of CuZnSOD and APX enhance salt stress tolerance in sweet potato

Abiotic stresses cause accumulation of reactive oxygen species (ROS) in plants, CuZnSOD and APX are first line defenses against ROS caused by oxidative stress. In this study, CuZnSOD and APX were transferred into salt sensitive sweet potato (cv. Xushu 55–2) under control of stress inducible SWPA2 promoter and tolerance to salt stress was evaluated. When 100 mM NaCl was used to treat stem cuttings, transgenic plants showed enhanced tolerance compared to wild type (WT) plants. Rooting was significantly retarded in WT plants whereas all transgenic plants had significantly enhanced root growth under salt stress. Integration of SOD gene was confirmed by southern blot analysis, and the copy number ranged from 1 to 3. The expression levels of CuZnSOD and APX in transgenic plants were significantly increased up to 13.3 and 7.8 folds to WT under salinity conditions, respectively. SOD and APX activity and ROS staining showed enzyme activities of transgenic plants were increased under salt stress. These results show that CuZnSOD and APX have important roles in enhancing the salt tolerance of sweet potato.

Overexpression of copper/zinc superoxide dismutase in the median preoptic nucleus improves cardiac function after myocardial infarction in the rat.

Previous reports indicate that overexpression of copper/zinc superoxide dismutase (CuZnSOD), an intracellular superoxide (O2 (•-) ) scavenging enzyme, in the brain subfornical organ improves cardiac function in a mouse model of heart failure (HF). A downstream hypothalamic site, the MnPO, may act as a relay centre for O2 (•-) to serve as a mediator in the pathophysiology of HF. To test the hypothesis that elevated O2 (•-) in the MnPO contributes to the pathophysiology of HF and decreased cardiac function, we injected adenovirus encoding CuZnSOD (AdCuZnSOD, n=7) or control empty adenovirus vector (AdEmpty, n=7) into the MnPO of normal rats. Subsequently, rats were subjected to coronary artery ligation to create a myocardial infarct (MI) of the left ventricle. Cardiac function was monitored via echocardiography. Upon completion, rat brains were examined for CuZnSOD expression in MnPO via immunofluorescence and histopathological analyses of cardiac infarct size were conducted. Baseline (EF) ejection fractions (%) of AdCuZnSOD and AdEmpty rats were 73±1 and 71±1, respectively. Two weeks after MI, EF was significantly decreased in both groups of rats (AdCuZnSOD: 51±3, AdEmpty: 46±1). In contrast, by 4weeks post MI, EF had improved to 64±2 in AdCuZnSOD rats, yet was only 52±1 in AdEmpty rats, and this was accompanied by lower plasma noradrenaline levels in AdCuZnSOD rats (0.49±0.19ng/mL) compared to AdEmpty rats (1.20±0.32ng/mL). In conclusion, despite decreases in EF early after MI, overexpression of CuZnSOD in the MnPO was related to an improvement in left ventricular function and concomitant decreased plasma noradrenaline levels 4weeks post MI.

Intermittent local periodontal inflammation causes endothelial dysfunction of the systemic artery via increased levels of hydrogen peroxide concomitantly with overexpression of superoxide dismutase

BackgroundThe present study was designed to examine whether the intermittent local periodontal inflammation induces endothelial dysfunction of the systemic artery caused by oxidative stress and if increased levels of hydrogen peroxide coexisted with overexpression of superoxide dismutase (SOD) as well as NADPH oxidase contribute to the oxidative stress. MethodsThe rats in lipopolysaccharides (LPS) group received 1500μg LPS injection to bilateral gingiva of the lower jaw a week interval from eight- to eleven-week-old. Isolated mandibles or aortas were subjected to the evaluation of histopathological changes, isometric force recordings, reactive oxygen species using 2′,7′-dichlorofluorescin diacetate (10−5mol/L) and protein expression of NADPH oxidase subunits and SOD, respectively. ResultsMandible sections demonstrated the periodontal inflammation only in the LPS group at three days, but not seven days, after the LSP injection. Acetylcholine (10−9 to 10−5mol/L)-induced relaxation was reduced only in aortas from the LPS group. Gp91ds-tat and PEG-catalase restored the impaired dilation in arteries from the LPS group. Levels of reactive oxygen species were enhanced in aortas from the LPS group, whereas the increment was abolished by the treatment with gp91-ds-tat or PEG-catalase. Expression of a NADPH oxidase subunit p47phox and CuZn-SOD increased in the LPS group. ConclusionsThe intermittent local periodontal inflammation induces systemic endothelial dysfunction caused by overproduction of reactive oxygen species in the systemic artery of rats and that overexpression of CuZn-SOD as well as a NADPH oxidase cytosolic subunit contributes to increased levels of hydrogen peroxide in blood vessels of this animal model.

Improved antioxidative defence protects insulin-producing cells against homocysteine toxicity

Homocysteine (HC) is considered to play an important role in the development of metabolic syndrome complications. Insulin-producing cells are prone to HC toxicity and this has been linked to oxidative stress. However, the exact mechanisms remain unknown. Therefore it was the aim of this study to determine the nature of reactive oxygen species responsible for HC toxicity.Chronic exposure of RINm5F and INS1E insulin-producing cells to HC decreased cell viability and glucose-induced insulin secretion in a concentration-dependent manner and led to a significant induction of hydrogen peroxide generation in the cytosolic, but not the mitochondrial compartment of the cell. Cytosolic overexpression of catalase, a hydrogen peroxide detoxifying enzyme, provided a significant protection against viability loss and hydrogen peroxide generation, while mitochondrial overexpression of catalase did not protect against HC toxicity. Overexpression of CuZnSOD, a cytosolic superoxide dismutating enzyme, also protected against HC toxicity. However, the best protection was achieved in the case of a combined overexpression of CuZnSOD and catalase. Incubation of cells in combination with alloxan resulted in a significant increase of HC toxicity and an increase of hydrogen peroxide generation. Overexpression of CuZnSOD or catalase protected against the toxicity of HC plus alloxan, with a superior protection achieved again by combined overexpression. The results indicate that HC induces oxidative stress in insulin-producing cells by stimulation of superoxide radical and hydrogen peroxide generation in the cytoplasm. The low antioxidative defence status makes the insulin-producing cells very vulnerable to HC toxicity.

Simultaneous overexpression of CuZnSOD and cAPX from Arachis hypogaea leads to salinity stress tolerance in tobacco

Stress leads to generation of reactive oxygen species in living cells, which are scavenged by antioxidant enzymes. In the present study, genes encoding for two different antioxidant enzymes, namely cytosolic superoxide dismutase and cytosolic ascorbate peroxidase isolated from salt-tolerant cell lines of Arachis hypogaea, were simultaneously overexpressed in tobacco (Nicotiana tabacum cv. Xanthi) and the effect of their overexpression on alleviation of salinity stress was evaluated. The co-expression of AhCuZnSOD and AhcAPX in tobacco plants helped the resulting transgenic plants in overcoming salt stress. Compared to the wild-type plants, transgenic plants survived longer periods of salinity stress and displayed improved recovery after removal of the stress. The transgenic tobacco plants exhibited better photosynthetic efficiency, higher germination rate, more chlorophyll content, higher levels of total antioxidant enzyme activities, greater water retention capacity, higher proline accumulation, lower level of malondialdehyde content, and reactive oxygen species accumulation under stress conditions in comparison to the WT plants. Our analysis revealed that combined overexpression of the two antioxidant enzymes improved the salinity tolerance in transgenic plants.

Overexpression of CuZnSOD from Arachis hypogaea alleviates salinity and drought stress in tobacco.

Overexpression of CuZnSOD gene from Arachis hypogaea demonstrating its involvement in abiotic stress tolerance. Abiotic stress is accompanied by the formation of reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, and hydroxyl radicals, causing extensive cellular damage and inhibition of photosynthesis that limit the plant productivity. The level of ROS in cells needs to be tightly regulated and the toxic effects of ROS are countered by enzymatic as well as non-enzymatic antioxidant systems. The superoxide dismutase is the first enzyme involved in the detoxification of ROS and converts superoxide (O2(·-)) radicals to H2O2. A full-length cDNA clone encoding a CuZnSOD, named AhCuZnSOD, was isolated from the salt tolerant cell lines of Arachis hypogaea, stably thriving at 200 mM NaCl. The cell line showed higher transcript accumulation under multiple abiotic stresses, including drought, salinity, cold and oxidative stress treatment. The functional role of AhCuZnSOD in alleviation of abiotic stress was assessed by its overexpression in transgenic tobacco plants. The T1 transgenic plants showed improved tolerance to salinity and dehydration stress as indicated by higher seed germination and better chlorophyll content. The transgenic plants survived under longer periods of water deficiency and salinity stress and displayed improved recovery after rehydration compared to the wild type (WT) plants. The enhanced level of the transgene correlated with higher relative water content, less electrolyte damage, less malondialdehyde, higher antioxidant enzyme activity, H2O2 and O2(·-) accumulation under stress conditions compared to WT plants. Our results substantiate that increased levels of SOD activity brought about by overexpression of AhCuZnSOD gene may play an important role in ameliorating oxidative injury induced by various environmental stresses.

Over-expressed copper/zinc superoxide dismutase localizes to mitochondria in neurons inhibiting the angiotensin II-mediated increase in mitochondrial superoxide

Angiotensin II (AngII) is the main effector peptide of the renin–angiotensin system (RAS), and contributes to the pathogenesis of cardiovascular disease by exerting its effects on an array of different cell types, including central neurons. AngII intra-neuronal signaling is mediated, at least in part, by reactive oxygen species, particularly superoxide (O2−). Recently, it has been discovered that mitochondria are a major subcellular source of AngII-induced O2−. We have previously reported that over-expression of manganese superoxide dismutase (MnSOD), a mitochondrial matrix-localized O2− scavenging enzyme, inhibits AngII intra-neuronal signaling. Interestingly, over-expression of copper/zinc superoxide dismutase (CuZnSOD), which is believed to be primarily localized to the cytoplasm, similarly inhibits AngII intra-neuronal signaling and provides protection against AngII-mediated neurogenic hypertension. Herein, we tested the hypothesis that CuZnSOD over-expression in central neurons localizes to mitochondria and inhibits AngII intra-neuronal signaling by scavenging mitochondrial O2−. Using a neuronal cell culture model (CATH.a neurons), we demonstrate that both endogenous and adenovirus-mediated over-expressed CuZnSOD (AdCuZnSOD) are present in mitochondria. Furthermore, we show that over-expression of CuZnSOD attenuates the AngII-mediated increase in mitochondrial O2− levels and the AngII-induced inhibition of neuronal potassium current. Taken together, these data clearly show that over-expressed CuZnSOD in neurons localizes in mitochondria, scavenges AngII-induced mitochondrial O2−, and inhibits AngII intra-neuronal signaling.

Overexpression of CuZnSOD in median preoptic nucleus improves cardiac function after myocardial infarction in the rat

It has been shown that central overexpression of the superoxide scavenging enzyme, Cu/Zn superoxide dismutase (SOD), in the subfornical organ improves cardiac function in a mouse model of heart failure (HF). A downstream hypothalamic site, the median preoptic nucleus (MnPO), may act as a relay center for reactive oxygen species to act as mediators in the pathophysiology of HF. To test the hypothesis that elevated superoxide in the MnPO is related to the pathophysiology of HF and decreased cardiac function, we injected adenovirus encoding CuZnSOD (AdSOD, n=2) or control empty vector (AdE, n=3) into the MnPO of normal rats. Subsequently, rats were subjected to coronary artery ligation to create a myocardial infarct (MI) of the left ventricle. Cardiac function was monitored at 2 week intervals via echocardiography. Upon completion, rat brains were examined for SOD expression in MnPO via immunofluorescence and histopathological analyses of cardiac infarct size were conducted. Baseline (EF) ejection fractions (%) of AdSOD and AdE rats were 62±4 and 67±2, respectively. Two weeks after MI, EF was significantly decreased in both groups of rats (AdSOD: 38±3, AdE: 48±4). In contrast by 6 weeks post MI, EF had improved to 52±1 in AdSOD rats yet was only 41±6 in AdE rats. In conclusion, despite decreases in EF early after MI, overexpression of SOD in the MnPO was related to an improvement in left ventricular function 6 weeks post MI.

Enhanced tolerance to methyl viologen-induced oxidative stress and high temperature in transgenic potato plants overexpressing the CuZnSOD, APX and NDPK2 genes

Oxidative stress is a major threat for plants exposed to various environmental stresses. Previous studies found that transgenic potato plants expressing both copper zinc superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) (referred to as SSA plants), or nucleoside diphosphate kinase 2 (NDPK2) (SN plants), showed enhanced tolerance to methyl viologen (MV)-induced oxidative stress and high temperature. This study aimed to develop transgenic plants that were more tolerant of oxidative stress by introducing the NDPK2 gene into SSA potato plants under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter to create SSAN plants. SSAN leaf discs and whole plants showed enhanced tolerance to MV, as compared to SSA, SN or non-transgenic (NT) plants. SSAN plants sprayed with 400 µM MV exhibited about 53 and 83% less visible damage than did SSA and SN plants, respectively. The expression levels of the CuZnSOD, APX and NDPK2 genes in SSAN plants following MV treatment correlated well with MV tolerance. SOD, APX, NDPK and catalase antioxidant enzyme activities were also increased in MV-treated SSAN plants. In addition, SSAN plants were more tolerant to high temperature stress at 42°C, exhibiting a 6.2% reduction in photosynthetic activity as compared to plants grown at 25°C. In contrast, the photosynthetic activities of SN and SSA plants decreased by 50 and 18%, respectively. These results indicate that the simultaneous overexpression of CuZnSOD, APX and NDPK2 is more effective than single or double transgene expression for developing plants with enhanced tolerance to various environmental stresses.

CuZnSOD and MnSOD inhibit metabolic stress-induced necrosis and multicellular tumour spheroid growth

CuZnSOD and MnSOD have been shown to exert tumour suppressive activities; however, their exact molecular mechanism is still unclear. We investigated the molecular mechanism underlying the tumour suppressive activities of CuZnSOD and MnSOD using multicellular tumour spheroid (MTS), an in vitro tumour model. Overexpression of CuZnSOD and MnSOD significantly suppressed the growth of A549 and MCF-7 MTS, supporting a critical role(s) of reactive oxygen species (ROS) in tumour growth. In solid tumours, ROS is produced by metabolic stress due to insufficient oxygen and glucose supply and induces necrosis that is known to promote tumour progression by releasing the proinflammatory cytokine HMGB1. We observed that CuZnSOD and MnSOD overexpression prevents metabolic stress-induced necrosis and HMGB1 release by inhibiting mitochondrial ROS and intracellular O2- production in response to glucose depletion in two dimensional cell culture. CuZnSOD and MnSOD overexpression also significantly repressed the occurrence of necrosis that was observed during MTS culture. In human tumour tissues including lung pulmonary adenocarcinoma, CuZnSOD and MnSOD expression was detected in the para-necrotic region that was identified by the expression of a hypoxic marker carbonic anhydrase (CA) IX. These results suggest that CuZnSOD and MnSOD may suppress tumour growth through inhibiting metabolic stress-induced necrosis and HMGB1 release via inhibiting metabolic stress-induced mitochondrial ROS production.

Radioprotektion des Normalgewebes durch Überexpression der Kupfer-Zink- und Mangan-Superoxiddismutase-Gene

Protection of normal tissue against radiation-induced damage may increase the therapeutic ratio of radiotherapy. A promising strategy for testing this approach is gene therapy-mediated overexpression of the copper-zinc (CuZnSOD) or manganese superoxide dismutase (MnSOD) using recombinant adeno-associated viral (rAAV2) vectors. The purpose of this study was to test the modulating effects of the SOD genes on human primary lung fibroblasts (HPLF) after irradiation. HPLF were transduced with rAAV2 vectors containing cDNA for the CuZnSOD, MnSOD or a control gene. The cells were irradiated (1-6 Gy), and gene transfer efficiency, apoptosis, protein expression/activity, and radiosensitivity measured by the colony-forming assay determined. After transduction, 90.0% +/- 6.4% of the cells expressed the transgene. A significant fivefold overexpression of both SOD was confirmed by an SOD activity assay (control: 21.1 +/- 12.6, CuZnSOD: 95.1 +/- 17.1, MnSOD: 108.5 +/- 36.0 U SOD/mg protein) and immunohistochemistry. CuZnSOD and MnSOD overexpression resulted in a significant radioprotection of HPLF compared to controls (surviving fraction [SF] ratio SOD/control > 1): CuZnSOD: 1.18-fold (95% confidence interval [CI]: 1.06-1.32; p = 0.005), MnSOD: 1.23-fold (95% CI: 1.07-1.43; p = 0.01). Overexpression of CuZnSOD and MnSOD in HPLF mediated an increase in clonogenic survival after irradiation compared to controls. In previous works, a lack of radioprotection in SOD-overexpressing tumor cells was observed. Therefore, the present results suggest that rAAV2 vectors are promising tools for the delivery of radioprotective genes in normal tissue.

Effects of overexpression of antioxidants on the release of cytochrome c and apoptosis-inducing factor in the model of ischemia

Apoptosis arises from neuronal damage following an ischemic insult. Apoptosis-inducing factor (AIF) is a protein released from mitochondria in response to pro-apoptotic signals which then translocates to the nucleus and triggers DNA fragmentation. In parallel with this, pro-apoptotic signals cause the release of cytochrome c from mitochondria, activating caspase-dependent apoptosis. During post-ischemic reperfusion, reactive oxygen species (ROS) are formed in excess in mitochondria and can play a role in initiating apoptosis. In cultures, ROS are formed during post oxygen glucose deprivation (OGD) normoxia/normoglycemia that is used as a model for ischemia. In this study, we delivered viral vectors to overexpress antioxidants (GPX, catalase, CuZnSOD, or MnSOD) in mixed cortical cultures, in order to investigate the effects of ROS-reduction on the release of cytochrome c and AIF. Overexpression of MnSOD, CuZnSOD, catalase or GPX all prevented AIF translocation from mitochondria to the nucleus. Potentially, this could reflect broadly non-specific protection due to reducing ROS load. Arguing against this, overexpression of the same antioxidants did not inhibit cytochrome c release. These findings suggest a specific interaction between ROS formation and the caspase-independent route of apoptosis.

Superoxide dismutase attenuates hyperoxia-induced interleukin-8 induction via AP-1

Exposure of lung epithelial cells to hyperoxia results in the generation of excess reactive oxygen species (ROS), cell damage, and production of proinflammatory cytokines (interleukin-8; IL-8). Although activation of the NF-κB and c-Jun N-terminal kinase (JNK)/activator protein (AP)-1 transcription pathways occurs in hyperoxia, it is unclear whether activation of the AP-1 pathway has a direct impact on IL-8 production and whether overexpression of superoxide dismutase (SOD) can mitigate these proinflammatory processes. A549 cells were exposed to 95% O 2, and ROS production, AP-1 activation, and IL-8 levels were determined. Experimental groups included cells transduced with a recombinant adenovirus encoding CuZnSOD or MnSOD (two- to threefold increased activity) or transfected with a JNK1 small interfering RNA (RNAi). Hyperoxia resulted in significant increases in ROS generation, AP-1 activation, and IL-8 production, which were significantly attenuated by overexpression of either MnSOD or CuZnSOD. JNK1 RNAi also moderated IL-8 induction. The data indicate that activation of JNK1/AP-1 and subsequent IL-8 induction in hyperoxia are mediated by intracellular ROS, with SOD having significant protective effects.

Adaptation to chronic MG132 reduces oxidative toxicity by a CuZnSOD‐dependent mechanism

To study whether and how cells adapt to chronic cellular stress, we exposed PC12 cells to the proteasome inhibitor MG132 (0.1 microM) for 2 weeks and longer. This treatment reduced chymotrypsin-like proteasome activity by 47% and was associated with protection against both 6-hydroxydopamine (6-OHDA; 100 microM) and higher dose MG132 (40 microM). Protection developed slowly over the course of the first 2 weeks of exposure and was chronic thereafter. There was no change in total GSH levels after MG132. Buthionine sulfoximine (100 microM) reduced GSH levels by 60%, but exacerbated 6-OHDA toxicity to the same extent in both MG132-treated and control cells and failed to reduce MG132-induced protection. Chronic MG132 resulted in elevated antioxidant proteins CuZn superoxide dismutase (SOD; +55%), MnSOD (+21%), and catalase (+15%), as well as chaperone heat-shock protein 70 (+42%). Examination of SOD enzyme activity revealed higher levels of CuZnSOD (+40%), with no change in MnSOD. We further assessed the mechanism of protection by reducing CuZnSOD levels with two independent siRNA sequences, both of which successfully attenuated protection against 6-OHDA. Previous reports suggested that artificial over-expression of CuZnSOD in dopaminergic cells is protective. Our data complement such observations, revealing that dopaminergic cells are also able to use endogenous CuZnSOD in self-defensive adaptations to chronic stress, and that they can even do so in the face of extensive GSH loss.

Superoxide scavenging in the paraventricular nucleus (PVN) reduces sympathoexcitation and improves cardiac function following myocardial infarction

We have shown that forebrain oxidative stress is involved in the increased sympathetic output that accompanies myocardial infarction (MI)‐induced heart failure in mice. Here we hypothesized that removal of superoxide from the PVN, a brain region controlling neurohumoral drive, would normalize sympathetic output and improve cardiac function following MI. Male C57BL/6 mice received dual PVN injections (200nL) of adenovirus encoding copper‐zinc superoxide dismutase (CuZnSOD, 1×1011 pfu/mL) or control β‐gal (0.9×1011 pfu/mL), followed by ligation of the left anterior descending artery to cause MI. Heart function was assessed by high resolution echocardiography and sympathetic output by norepinephrine (NE) ELISA 14 days later. MI elevated PVN superoxide levels (DHE fluorescence 1.98 fold sham ± 0.21, p<0.01, n=10) which were normalized by CuZnSOD overexpression (1.09 ± 0.14, p<0.01, n=10). MI decreased ejection fraction (29.1 ± 4.2% vs sham 54.8 ± 3.7%, p<0.01, n=16) and increased left ventricle end‐volume (87.7±6.5 vs sham 48.1±2.9 μL3, p<0.01, n=16) which were restored by CuZnSOD (52.3 ± 4.3%, 50.7±3.3 μL3, p<0.01, n=11). NE levels were normalized in CuZnSOD‐treated mice (sham 200±24, MI 491±42, MI CuZnSOD 354±37 ng/mL, p<0.05, n=10–11), implicating oxidative stress in PVN in increasing sympathetic drive after MI. These data support that ROS scavenging in the PVN can improve cardiac function following MI.

Overexpression of CuZnSOD or MnSOD protects satellite cells from doxorubicin‐induced apoptosis

Overexpression of CuZnSOD or MnSOD protects satellite cells from doxorubicin‐induced apoptosis

Induction of Oxidative Stress Response by the Mycotoxin Patulin in Mammalian Cells

Patulin (PAT), a mycotoxin mainly produced by Penicillium and Aspergillus, is found in various foods and feeds. In the present study, its effects on oxidative stress in various mammalian cell lines were investigated. When cell-permeating fluorescent dyes were used as indicators of the generation of reactive oxygen species (ROS), we found that PAT treatment directly increased intracellular oxidative stress in human embryonic kidney (HEK293) and human promyelocytic leukemia (HL-60) cells. Lipid peroxidation levels were also significantly increased in HL-60 cells and mouse kidney homogenates treated with PAT. Suppression of CuZn-superoxide dismutase (SOD) expression in mammalian cells by small interfering RNA resulted in an increase in PAT-mediated membrane damage, while overexpression of human CuZn-SOD or catalase led to a reduction in damage, indicating the involvement of ROS in PAT toxicity. Pretreatment of HEK293 cells with Tiron, a free radical scavenger, reduced the phosphorylation levels of extracellular signal-regulated kinase (ERK) 1/2 elicited by PAT. The ERK1/2 signaling pathway inhibitor, U0126, also significantly decreased the levels of ROS associated with PAT treatment. These findings indicate that PAT treatment results in the ROS production in mammalian cells, and ROS partially contributes to PAT-induced cytotoxicity. Activation of ERK1/2 signaling pathway is correlated with PAT-mediated ROS.