Identification and functional characterization of a superoxide dismutase (CuZnSOD) from Pinctada fucata martensii.

Copper/zinc superoxide dismutase (Cu/Zn-SOD) can effectively eliminate reactive oxygen species (ROS)，avoid damage from O2 to the body, and maintain O2 balance. In this study, multi-step high-performance liquid chromatography (HPLC), combined with Mass Spectrometry (MS), was used to isolate and identify Cu/Zn-SOD from the serum of Pinctada fucata martensii (P. f. martensii) and was designated as PmECSOD. With a length of 1864 bp and an open reading frame (ORF) of 1422 bp, the cDNA encodes a 473 amino acid protein. The PmECSOD transcript was detected in multiple tissues by quantitative real-time PCR (qRT-PCR), with its highest expression level being in the gills. Additionally, the temporal expression of PmECSOD mRNA in the hemolymph was highest at 48 h after in vivo stimulation with Escherichia coli and Micrococcus luteus. The results from this study provide a valuable base for further exploration of molluscan innate immunity and immune response.

Superoxide Dismutase and Clopidogrel: A Potential Role in Peripheral Arterial Disease Treatment.

Oxidative stress plays a crucial role in the pathogenesis of peripheral artery disease (PAD). This study aimed to investigate the effect of clopidogrel on oxidative stress in PAD patients. Seventy subjects were divided into three groups: PAD patients before treatment (B-PAD), PAD patients after treatment with clopidogrel (A-PAD), and healthy controls. Serum levels of superoxide dismutase (SOD), copper (Cu), zinc (Zn), manganese (Mn), and oxidized protein were measured. SOD activities were also determined. The results showed that SOD activities, and SOD specific activities were significantly decreased in PAD patients compared to healthy individuals. After treatment with clopidogrel, SOD activities, and SOD specific activities were continuously decrease in PAD patients. The SOD and oxidized protein concentrations were significantly increased in PAD patients compared to healthy individuals. After treatment with clopidogrel, the oxidized protein concentration was significantly decreased, while SOD concentration was significantly increased in PAD patients. These findings suggest that the treatment by clopidogrel stimulated the production of the enzyme but the ratio of active enzyme remained low. The decrease in oxidized protein can be explained by the treatment having antioxidant efficacy that may have compensated for the deficiency in enzyme activity and led to a decrease in oxidized protein. Additionally, the results of this study provide promising evidence that oxidative stress biomarkers including SOD concentration, T-SOD activity, Mn-SOD activity, and oxidized protein levels have potential utility in the diagnosis and management of PAD.

Potato Stu-miR398b-3p Negatively Regulates Cu/Zn-SOD Response to Drought Tolerance.

One of the main impacts of drought stress on plants is an excessive buildup of reactive oxygen species (ROS). A large number of ·OH, highly toxic to cells, will be produced if too much ROS is not quickly cleared. At the heart of antioxidant enzymes is superoxide dismutase (SOD), which is the first antioxidant enzyme to function in the active oxygen scavenging system. To shield cells from oxidative injury, SOD dismutation superoxide anion free radicals generate hydrogen peroxide and molecule oxygen. Cu/Zn SOD is a kind of SOD antioxidant enzyme that is mostly found in higher plants' cytoplasm and chloroplasts. Other studies have demonstrated the significance of the miR398s family of miRNAs in the response of plants to environmental stress. The cleavage location of potato stu-miR398b-3p on Cu/Zn SOD mRNA was verified using RLM-5'RACE. Using the potato variety 'Desiree', the stu-miR398b-3p overexpression mutant was created, and transgenic lines were raised. SOD activity in transgenic lines was discovered to be decreased during drought stress, although other antioxidant enzyme activities were mostly unaltered. Transgenic plants will wilt more quickly than wild-type plants without irrigation. Additionally, this demonstrates that the response of Cu/Zn SOD to drought stress is adversely regulated by potato stu-miR398b-3p.

An extracellular Cu/Zn superoxide dismutase from Neocaridina denticulata sinensis: cDNA cloning, mRNA expression and characterizations of recombinant protein.

Neocaridina denticulata sinensis possesses characters of rapid growth, tenacious vitality, short growth cycle, transparent, and easy feeding. Therefore, it is gradually being developed into an animal model for basic research on decapod crustaceans. Herein, a Cu/Zn superoxide dismutase (Cu/Zn-SOD), named as Nd-ecCu/Zn-SOD, was identified and characterized from N. denticulata sinensis. The full-length cDNA sequence of Nd-ecCu/Zn-SOD is 829 bp containing a 684 bp open reading frame, which encodes a protein of 227 amino acid residues with a typical Sod_Cu domain. The quantitative real-time PCR analysis showed that Nd-ecCu/Zn-SOD mRNA was expressed in all the tested tissues. Under challenge with copper, the mRNA expression of Nd-ecCu/Zn-SOD reached the maximum at 6 h, and decreased until 24 h. After 24 h of exposure, its expression was up-regulated significantly at 36 h. After then its expression sharply decreased with a comeback at 48 h. The result indicated that Nd-ecCu/Zn-SOD might play an important role in the stress response of N. denticulata sinensis. The expression of Nd-ecCu/Zn-SOD in gills challenged with Vibrio parahaemolyticus changed in a time-dependent manner. Nd-ecCu/Zn-SOD was lowly expressed in early developmental stages by RNA-Seq technology, yet it showed that a cyclical rise and fall occurred between middle stages and late stages. In addition, Nd-ecCu/Zn-SOD was recombinantly expressed using E. coli and the recombinant protein was purified as a single band on SDS-PAGE. The recombinant Nd-ecCu/Zn-SOD (rNd-ecCu/Zn-SOD) existed enzymatic activity under a wide range of temperature and pH. The exposure of metal ions was found that Zn2+, Mg2+, Ca2+, Ba2+, and Cu2+ could inhibit the enzymatic activity of rNd-ecCu/Zn-SOD, and Mn2+ increased the enzymatic activity of rNd-ecCu/Zn-SOD. These results indicate that Nd-ecCu/Zn-SOD may play a pivotal role in resistant against oxidative damage and act as a biomarker under stressful environment.

Characterization of Copper/Zinc Superoxide Dismutase Activity on Phascolosoma esculenta (Sipuncula: Phascolosomatidea) and Its Protection from Oxidative Stress Induced by Cadmium.

Phascolosoma esculenta, an economically important species inhabiting the high tide areas of the intertidal zone, is particularly sensitive to water pollution. Considering its potential as a bioindicator, studies on the ecotoxicology of P. esculenta are imperative. The toxic effects of cadmium (Cd) were analyzed by exposing P. esculenta to different concentrations of Cd (6, 24, 96 mg/L). In this study, the changes in the antioxidative indexes of total superoxide dismutase (T-SOD), glutathione s-transferase (GST), reduced glutathione (GSH), and microscale malondialdehyde (MDA) were recorded. Copper/zinc superoxide dismutase (Cu/Zn SOD) is one of the most important free radical scavenging members. To reveal the antioxidative function of P. esculenta, an important member of the antioxidative system, designated Pe-Cu/Zn SOD, was cloned and analyzed. Phylogenic analysis revealed that Pe-Cu/Zn SOD was located in the invertebrate evolutionary branch of intracellular Cu/Zn SOD (icCu/Zn SOD). The quantitative real-time polymerase chain reaction results showed that Pe-Cu/Zn SOD messenger ribonucleic acid was widely expressed in all tissues examined. The highest expression levels in coelomic fluid after Cd exposure indicated its function in the stress response. Using a prokaryotic expression system, we obtained a Pe-Cu/Zn SOD recombinant protein, which enhanced the heavy metal tolerance of Escherichia coli. In vivo assays also confirmed that the Pe-Cu/Zn SOD recombinant protein had an antioxidative and free radical scavenging ability. A Cd toxicity experiment, in which purified Pe-Cu/Zn SOD protein was injected into the body cavities of P. esculenta, showed that the reactive oxygen species content in the coelomic fluid of the experimental group was significantly lower compared with the control group. These results suggest that Pe-Cu/Zn SOD played a role in Cd detoxification by chelating heavy metal ions and scavenging reactive oxygen free radicals, and that P. esculenta could be used as a bioindicator to evaluate heavy metal pollution.

Evaluation of Zn2+- and Cu2+-Binding Affinities of Native Cu,Zn-SOD1 and Its G93A Mutant by LC-ICP MS.

The tight binding of Cu and Zn ions to superoxide dismutase 1 (SOD1) maintains the protein stability, associated with amyotrophic lateral sclerosis (ALS). Yet, the quantitative studies remain to be explored for the metal-binding affinity of wild-type SOD1 and its mutants. We have investigated the demetallation of Cu,Zn-SOD1 and its ALS-related G93A mutant in the presence of different standard metal ion chelators at varying temperatures by using an LC-ICP MS-based approach and fast size-exclusion chromatography. Our results showed that from the slow first-order kinetics both metal ions Zn2+ and Cu2+ were released simultaneously from the protein at elevated temperatures. The rate of the release depends on the concentration of chelating ligands but is almost independent of their metal-binding affinities. Similar studies with the G93A mutant of Cu,Zn-SOD1 revealed slightly faster metal-release. The demetallation of Cu,Zn-SOD1 comes always to completion, which hindered the calculation of the KD values. From the Arrhenius plots of the demetallation in the absence of chelators ΔH‡ = 173 kJ/mol for wt and 191 kJ/mol for G93A mutant Cu,Zn-SOD1 was estimated. Obtained high ΔH values are indicative of the occurrence of protein conformational changes before demetallation and we concluded that Cu,Zn-SOD1 complex is in native conditions kinetically inert. The fibrillization of both forms of SOD1 was similar.

Superoxide dismutase (SOD) as a selection criterion for triticale grain yield under drought stress: a comprehensive study on genomics and expression profiling, bioinformatics, heritability, and phenotypic variability.

BACKGROUND: The main objectives of this study were to find the possible structural association between the activity of enzymatic antioxidants and the grain yield of triticale plants as well as identifying the genotypic variability which might be effective on this association. Accordingly, expression levels of superoxide dismutase (SOD) isozymes (Mn-SOD, Cu/Zn-SOD, and Fe-SOD) were appraised to distinguish any possible relationship between SOD expression and drought resistance of triticale. A novel analytical method for distinguishing elite genotypes based on measured features was proposed. Additionally, a new programing based on SAS-language (IML) was introduced to estimate the genetic parameters rooted from combined ANOVA model (linear mixed model), which is capable of being used in any field study other than the current one. METHODS: Thirty genotypes of triticale were studied under normal and drought stress conditions during 6 years (three different locations). Accordingly, based on the results of genetic variability, heatmap analysis, biplot graph, and clustering technique, two genotypes with the highest genetic distance were selected to appraise the differential expression profiling of three SOD isozyme in shoot and root organs. RESULTS: Field experiments and bioinformatics results showed that superoxide dismutase (SOD) was the most influential antioxidant in resistance of triticale to drought stress; therefore, it could be used as an indirect selection index in early stages to distinguish resistant genotypes to drought stress. Additionally, Mn-SOD and Fe-SOD showed roughly similar expression levels for both genotypes under drought stress. However, Cu/Zn-SOD expression level was higher in root and shoot of the tolerant genotype than the susceptible genotype. CONCLUSION: Heatmap analysis that is applied for the first time to screen suitable genotypes, showed to be highly capable of distinguishing elite genotypes and pointing out the proper features for selection criteria. Bioinformatics results indicated that SOD is more important than other enzymatic antioxidant for being considered as selection criteria or candidate gene for transgenic purposes. Based on expressional results, Mn-SOD announced as a general isozyme that is probably highly expressed in most of the species, while, Cu/Zn-SOD was introduced as a genotype specific isozyme that is likely more expressed in tolerant genotypes.

Acute dietary zinc deficiency in rats exacerbates myocardial ischaemia-reperfusion injury through depletion of glutathione.

Zn plays an important role in maintaining the anti-oxidant status within the heart and helps to counter the acute redox stress that occurs during myocardial ischaemia and reperfusion. Individuals with low Zn levels are at greater risk of developing an acute myocardial infarction; however, the impact of this on the extent of myocardial injury is unknown. The present study aimed to compare the effects of dietary Zn depletion with in vitro removal of Zn (N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN)) on the outcome of acute myocardial infarction and vascular function. Male Sprague-Dawley rats were fed either a Zn-adequate (35 mg Zn/kg diet) or Zn-deficient (<1 mg Zn/kg diet) diet for 2 weeks before heart isolation. Perfused hearts were subjected to a 30 min ischaemia/2 h reperfusion (I/R) protocol, during which time ventricular arrhythmias were recorded and after which infarct size was measured, along with markers of anti-oxidant status. In separate experiments, hearts were challenged with the Zn chelator TPEN (10 µm) before ischaemia onset. Both dietary and TPEN-induced Zn depletion significantly extended infarct size; dietary Zn depletion was associated with reduced total cardiac glutathione (GSH) levels, while TPEN decreased cardiac superoxide dismutase 1 levels. TPEN, but not dietary Zn depletion, also suppressed ventricular arrhythmias and depressed vascular responses to nitric oxide. These findings demonstrate that both modes of Zn depletion worsen the outcome from I/R but through different mechanisms. Dietary Zn deficiency, resulting in reduced cardiac GSH, is the most appropriate model for determining the role of endogenous Zn in I/R injury.

The distribution, expression of the Cu/Zn superoxide dismutase in Apostichopus japonicus and its function for sea cucumber immunity.

Cu/Zn superoxide dismutases (SODs) are antioxidative metalloenzymes that exist ubiquitously in different species and are distributed widely in various tissues and cell types. In this study, the distribution and biological function of the Cu/Zn superoxide dismutase in Apostichopus japonicus (AjSOD1) is first characterized. The AjSOD1 cDNA is 1219 bp in length and contains an open reading frame (ORF) of 459 bp that encodes a protein of 152 amino acids with a deduced molecular weight of 15.47 kDa and a predicted isoelectric point of 5.65. The Cu2+/Zn2+ binding domain and conserved residues were found in the AjSOD1 amino acid sequence. A quantitative reverse transcriptase real-time PCR (qRT-PCR) assay was developed to assess the expression of AjSOD1 in different tissues. Spatial distribution analysis showed that AjSOD1 was constitutively expressed in all tested tissues, with strong expression in the intestine and weak expression in the respiratory tree. mRNA Expression of AjSOD1 was significantly upregulated when challenged with the pathogen Vibrio splendidus. Functional investigation revealed that recombinant AjSOD1 displayed good antioxidant activity. More importantly, the addition of AjSOD1 resulted in a significant decrease in coelomocyte apoptosis by LPS/H2O2 challenge in vitro. The results indicate that sea cucumber SOD1 may play critical roles not only in the defense against oxidative stress but also in the innate immune defense against bacterial infections.

Identification of novel superoxide dismutase isoenzymes in the olive (Olea europaea L.) pollen.

BACKGROUND: Among antioxidant enzymes, the superoxide dismutase (SOD) family is a major actor in catalysing the disproportionation of superoxide. Apart from its role as antioxidant, these enzymes have a role in cell signalling, and Cu,Zn-SOD proteins are also major pollen allergens. In order to deepen our understanding of the SOD isoenzymes present in olive pollen and to analyse the molecular variability of the pollen Cu,Zn-SOD family, we carried out biochemical, transcriptomic and localization studies of pollen grains from different olive cultivars and other allergenic species. RESULTS: Olive pollen showed a high rate of total SOD activity in all cultivars assayed, which did not correlate with pollen viability. Mass spectrometry analysis together with activity assays and Western blotting experiments enabled us to identify new forms of Cu,Zn-SOD enzyme (including chloroplastidic and peroxisomal forms) as well as differentially expressed Mn-, Fe- and Cu,Zn-SOD isoenzymes among the pollen of different olive cultivars and allergenic species. Ultrastructural localization of Cu,Zn-SOD revealed its plastidial localization in the pollen grain. We also identified the occurrence of a shorter form of one of the cytosolic Cu,Zn-SOD enzymes, likely as the result of alternative splicing. This shorter enzyme showed lower SOD activity as compared to the full length form. CONCLUSIONS: The presence of multiple SOD isoenzymes in the olive pollen could be related to the need of finely tuning the ROS metabolism during the transition from its quiescent condition at maturity to a highly metabolically active state at germination.

Gene Disruption in Scedosporium aurantiacum: Proof of Concept with the Disruption of SODC Gene Encoding a Cytosolic Cu,Zn-Superoxide Dismutase.

Scedosporium species are opportunistic pathogens responsible for a large variety of infections in humans. An increasing occurrence was observed in patients with underlying conditions such as immunosuppression or cystic fibrosis. Indeed, the genus Scedosporium ranks the second among the filamentous fungi colonizing the respiratory tracts of the CF patients. To date, there is very scarce information on the pathogenic mechanisms, at least in part because of the limited genetic tools available. In the present study, we successfully developed an efficient transformation and targeted gene disruption approach on the species Scedosporium aurantiacum. The disruption cassette was constructed using double-joint PCR procedure, and resistance to hygromycin B as the selection marker. This proof of concept was performed on the functional gene SODC encoding the Cu,Zn-superoxide dismutase. Disruption of the SODC gene improved susceptibility of the fungus to oxidative stress. This technical advance should open new research areas and help to better understand the biology of Scedosporium species.

Recombinant protein transduction domain-Cu/Zn superoxide dismutase alleviates bone cancer pain via peroxiredoxin 4 modulation and antioxidation.

Bone cancer pain (BCP) is a serious chronic clinical condition and reactive oxygen species (ROS) were considered to be involved in its development and persistency. Normally, superoxide dismutase (SOD) converts superoxide anions to hydrogen peroxide (H2O2) and H2O2 is then naturalized to be water by peroxiredoxin 4. We reported previously that recombinant protein transduction domain (PTD)-Cu/Zn SOD effectively scavenged excessive ROS and prevented cardiomyocytes from hypoxia-reoxygenation damage. However, whether PTD-Cu/Zn SOD would prevent BCP development is unknown. In the current study, we found that an implanted carcinoma in the rat tibia induced remarkable hyperalgesia, increased H2O2 levels and decreased SOD and peroxiredoxin 4 levels. After administration of recombinant PTD-Cu/Zn SOD to these tumor-burden rats, their hyperalgesia was significantly attenuated and peroxiredoxin 4 expression was significantly increased. In addition, an increased expression of N-methyl-d-aspartic acid (NMDA) receptors and a decreased expression of γ-aminobutyric acid (GABA) receptors in this cancer pain were prevented by PTD-Cu/Zn SOD administration or peroxiredoxin 4 overexpression. Our data suggested that reactive oxygen species, at least in part, play a role in cancer metastatic pain development and persistency which can be attenuated by the adminstration of recombinant PTD-Cu/Zn SOD via the peroxiredoxin 4 modulation from oxidative stress.

Antioxidant defenses of Onychostoma macrolepis in response to thermal stress: Insight from mRNA expression and activity of superoxide dismutase and catalase.

Onychostoma macrolepis has becoming an endangered fish species in China, which population gradually declined in the past few decades due to the changing environment including elevated water temperature resulted from adverse weather events. The present study determined antioxidant defenses of O. macrolepis in response to thermal stress, aiming to understand the role of antioxidant system in adaptation of thermal stress for O. macrolepis. Experimental fish which were acclimated at 24 °C were stressed at 30 °C for 0 h, 1 h, 3 h, 6 h, 12 h, 24 h and 48 h, respectively. Change in mRNA expression of Cu/Zn superoxide dismutase (Cu/Zn-SOD) and catalase (CAT) and activity of SOD and CAT of the experimental fish with different stress time were determined. We cloned the full-length cDNA of Cu/Zn-SOD and CAT by means of RACE method, and analyzed their molecular characterization and tissue distribution. We discovered that the mRNA expression of the Cu/Zn-SOD in heart, liver, spleen, gill, intestine and the CAT in heart, liver, spleen, kidney, intestine and muscle of O. macrolepis significantly increased when water temperature increased from 24 °C to 30 °C, indicating a sensitive response of mRNA expression of Cu/Zn-SOD and CAT to the thermal stress. Moreover, the mRNA expression of the Cu/Zn-SOD and CAT were varied in different tissues, indicating different sensitivity of the tissues in response to thermal stress. Activity of the SOD in serum of O. macrolepis gradually increased from 1 h to 12 h sampling time, but significantly decreased at 24 h sampling time, compared to that of 0 h sampling time. And activity of the CAT in serum of O. macrolepis significantly decreased from 1 h to 12 h sampling time, and did not changed significantly at 24 h and 48 h sampling time, compared to that of 0 h sampling time. As such, MDA contents in the serum of O. macrolepis significantly decreased from 1 h to 6 h sampling time, but significantly increased at 12 h and 24 h sampling time, compared to that of 0 h sampling time. In summary, antioxidant system of the O. macrolepis can quickly response to short term thermal stress at 30 °C in form of both the mRNA expression of Cu/Zn-SOD and CAT and the activity of SOD and CAT, and consequently enhance the antioxidant defenses of O. macrolepis. However, thermal stress at 30 °C for 12 h-24 h seems to lead to oxidative damage of the O. macrolepis.

A cytoplasmic Cu-Zn superoxide dismutase SOD1 contributes to hyphal growth and virulence of Fusarium graminearum.

Superoxide dismutases (SODs) are scavengers of superoxide radicals, one of the main reactive oxygen species (ROS) in the cell. SOD-based ROS scavenging system constitutes the frontline defense against intra- and extracellular ROS, but the roles of SODs in the important cereal pathogen Fusarium graminearum are not very clear. There are five SOD genes in F. graminearum genome, encoding cytoplasmic Cu-Zn SOD1 and MnSOD3, mitochondrial MnSOD2 and FeSOD4, and extracellular CuSOD5. Previous studies reported that the expression of SOD1 increased during infection of wheat coleoptiles and florets. In this work we showed that the recombinant SOD1 protein had the superoxide dismutase activity in vitro, and that the SOD1-mRFP fusion protein localized in the cytoplasm of F. graminearum. The Δsod1 mutants had slightly reduced hyphal growth and markedly increased sensitivity to the intracellular ROS generator menadione. The conidial germination under extracellular oxidative stress was significantly delayed in the mutants. Wheat floret infection assay showed that the Δsod1 mutants had a reduced pathogenicity. Furthermore, the Δsod1 mutants had a significant reduction in production of deoxynivalenol mycotoxin. Our results indicate that the cytoplasmic Cu-Zn SOD1 affects fungal growth probably depending on detoxification of intracellular superoxide radicals, and that SOD1-mediated deoxynivalenol production contributes to the virulence of F. graminearum in wheat head infection.

Glycation vs. glycosylation: a tale of two different chemistries and biology in Alzheimer's disease.

In our previous studies, we reported that the activity of an anti-oxidant enzyme, Cu,Zn-superoxide dismutase (Cu,Zn-SOD) became decreased as the result of glycation in vitro and in vivo. Glycated Cu,Zn-SOD produces hydroxyl radicals in the presence of transition metals due to the formation of a Schiff base adduct and a subsequent Amadori product. This results in the site-specific cleavage of the molecule, followed by random fragmentation. The glycation of other anti-oxidant enzymes such as glutathione peroxidase and thioredoxin reductase results in a loss or decrease in enzyme activity under pathological conditions, resulting in oxidative stress. The inactivation of anti-oxidant enzymes induces oxidative stress in aging, diabetes and neurodegenerative disorders. It is well known that the levels of Amadori products and N(e)-(carboxylmethyl)lysine (CML) and other carbonyl compounds are increased in diabetes, a situation that will be discussed by the other authors in this special issue. We and others, reported that the glycation products accumulate in the brains of patients with Alzheimer's disease (AD) patients as well as in cerebrospinal fluid (CSF), suggesting that glycation plays a pivotal role in the development of AD. We also showed that enzymatic glycosylation is implicated in the pathogenesis of AD and that oxidative stress is also important in this process. Specific types of glycosylation reactions were found to be up- or downregulated in AD patients, and key AD-related molecules including the amyloid-precursor protein (APP), tau, and APP-cleaving enzymes were shown to be functionally modified as the result of glycosylation. These results suggest that glycation as well as glycosylation are involved in oxidative stress that is associated with aging, diabetes and neurodegenerative diseases such as AD.

Albuminuria, serum antioxidant enzyme levels and markers of hemolysis and inflammation in steady state children with sickle cell anemia.

BACKGROUND: Oxidative stress is thought to be involved in the pathogenesis of microalbuminuria in Sickle cell anemia (SCA). Antioxidant enzymes such as glutathione peroxidase (GPx) and Cu-Zn superoxide dismutase (SOD) may play an important protective role. This study aimed to evaluate the association between albuminuria and these two antioxidant enzymes. METHODS: We consecutively recruited Steady state children aged between 2 and 18 years old with established diagnosis of homozygous SCA in two hospitals of Kinshasa/DR Congo. The relationship between Urinary Albumin Creatinine Ratio (UACR) and other variables of interest (age, systolic blood pressure, diastolic blood pressure, plasma GPx and Cu-Zn SOD, free plasmatic hemoglobin, LDH, indirect bilirubin, white blood cells (WBC), percentage of fetal hemoglobin, serum iron, ferritin, CRP) was analyzed by Bivariate correlation (Pearson's correlation coefficient). Microalbuminuria was defined by urine albumin/creatinine ratio between 30 and 299 mg/g. RESULTS: Seventy Steady state Black African children with SCA (56% boys; average age 9.9 ± 4.3 years; 53% receiving hydroxyurea) were selected. Prevalence of microalbuminuria was 11.8%. LDH (r = 0.260; p = 0.033) and WBC count (r = 0.264; p = 0.033) were positively correlated with UACR whereas GPx (- 0.328; p = 0.007) and Cu-Zn SOD (- 0.210; p = 0.091) were negatively correlated with UACR. CONCLUSIONS: Albuminuria is associated with decreased antioxidant capacity and increased levels of markers of hemolysis and inflammation. Therefore, strategies targeting the reduction of sickling and subsequent hemolysis, oxidative stress and inflammation could help preventing or at least delaying the progression of kidney disease in SCA children.

The role of Cu/Zn-SOD and Mn-SOD in the immune response to oxidative stress and pathogen challenge in the clam Meretrix meretrix.

The copper/zinc superoxide dismutase (Cu/Zn-SOD) and manganese superoxide dismutase (Mn-SOD) could effectively eliminate reactive oxygen species (ROS) and maintain the redox balance of immune system. In the present study, the potential synergy of Cu/Zn-SOD and Mn-SOD in immune system was investigated in the clam Meretrix meretrix. The expression of Cu/Zn-SOD mainly distributed in hepatopancreas and that of Mn-SOD was higher in gill of M. meretrix, and their mRNA and protein activity paralleled with each other. In response to H2O2 challenge, Cu/Zn-SOD mRNA showed significantly higher level at 24 h post-challenge and Mn-SOD mRNA was significantly higher at 12 and 24 h post-challenge in the experimental clams than in the control clams (P<0.05). After injection with Vibrio-parahaemolyticus-related bacterium (MM21), the Cu/Zn-SOD mRNA was significantly up-regulated at 24 h and 48 h post-injection and Mn-SOD mRNA was significantly higher at 24 h post-injection in MM21-injected clams than in control clams (P<0.05), suggesting that both of them might involve in the immune defense to Vibrio challenge. The mRNA expression of Cu/Zn-SOD and Mn-SOD was examined in a Vibrio-resistant population and a control population after MM21 immersion challenge. The increased transcription of Cu/Zn-SOD and Mn-SOD in the resistant population suggested both of them could benefit the immune system to defend against pathogen infection. As expression of Mn-SOD mRNA depended on stimuli and was more easily inducible, its response to H2O2 and Vibrio challenge was earlier than Cu/Zn-SOD. Our study suggested the redox balance might play an important role in M. meretrix to resist pathogen infection.

Investigation on the interaction of nanoAg with Cu-Zn SOD.

Silver nanoparticles (nanoAg) are used more and more widely, particularly because of their antimicrobial properties. The effect of exposure to nanoAg on the structure of superoxide dismutase (SOD) was thoroughly investigated using fluorescence measurements, synchronous fluorescence spectroscopy, steady-state and time-resolved fluorescence quenching measurements, UV/Vis absorption spectroscopy, resonance light scattering (RLS), circular dichroism (CD), isothermal titration calorimetry (ITC) and high-resolution transmission electron microscopy (HRTEM). Through van der Waal's force, nanoAg interacted with Cu-Zn SOD and influenced the active site by inducing structural changes, which influenced the function of SOD. The fluorescence studies show that both static and dynamic quenching processes occur. This paper provides reference data for toxicological studies of nanoAg, which are important in the future development of nanotechnology.

Mitochondria-derived hydrogen peroxide selectively enhances T cell receptor-initiated signal transduction.

T cell receptor (TCR)-initiated signal transduction is reported to increase production of intracellular reactive oxygen species, such as superoxide (O2˙(-)) and hydrogen peroxide (H2O2), as second messengers. Although H2O2 can modulate signal transduction by inactivating protein phosphatases, the mechanism and the subcellular localization of intracellular H2O2 as a second messenger of the TCR are not known. The antioxidant enzyme superoxide dismutase (SOD) catalyzes the dismutation of highly reactive O2˙(-) into H2O2 and thus acts as an intracellular generator of H2O2. As charged O2˙(-) is unable to diffuse through intracellular membranes, cells express distinct SOD isoforms in the cytosol (Cu,Zn-SOD) and mitochondria (Mn-SOD), where they locally scavenge O2˙(-) leading to production of H2O2. A 2-fold organelle-specific overexpression of either SOD in Jurkat T cell lines increases intracellular production of H2O2 but does not alter the levels of intracellular H2O2 scavenging enzymes such as catalase, membrane-bound peroxiredoxin1 (Prx1), and cytosolic Prx2. We report that overexpression of Mn-SOD enhances tyrosine phosphorylation of TCR-associated membrane proximal signal transduction molecules Lck, LAT, ZAP70, PLCγ1, and SLP76 within 1 min of TCR cross-linking. This increase in mitochondrial H2O2 specifically modulates MAPK signaling through the JNK/cJun pathway, whereas overexpressing Cu,Zn-SOD had no effect on any of these TCR-mediated signaling molecules. As mitochondria translocate to the immunological synapse during TCR activation, we hypothesize this translocation provides the effective concentration of H2O2 required to selectively modulate downstream signal transduction pathways.

Hydrogen peroxide production regulates the mitochondrial function in insulin resistant muscle cells: effect of catalase overexpression.

The mitochondrial redox state plays a central role in the link between mitochondrial overloading and insulin resistance. However, the mechanism by which the ROS induce insulin resistance in skeletal muscle cells is not completely understood. We examined the association between mitochondrial function and H2O2 production in insulin resistant cells. Our hypothesis is that the low mitochondrial oxygen consumption leads to elevated ROS production by a mechanism associated with reduced PGC1α transcription and low content of phosphorylated CREB. The cells were transfected with either the encoded sequence for catalase overexpression or the specific siRNA for catalase inhibition. After transfection, myotubes were incubated with palmitic acid (500µM) and the insulin response, as well as mitochondrial function and fatty acid metabolism, was determined. The low mitochondrial oxygen consumption led to elevated ROS production by a mechanism associated with ß-oxidation of fatty acids. Rotenone was observed to reduce the ratio of ROS production. The elevated H2O2 production markedly decreased the PGC1α transcription, an effect that was accompanied by a reduced phosphorylation of Akt and CREB. The catalase transfection prevented the reduction in the phosphorylated level of Akt and upregulated the levels of phosphorylated CREB. The mitochondrial function was elevated and H2O2 production reduced, thus increasing the insulin sensitivity. The catalase overexpression improved mitochondrial respiration protecting the cells from fatty acid-induced, insulin resistance. This effect indicates that control of hydrogen peroxide production regulates the mitochondrial respiration preventing the insulin resistance in skeletal muscle cells by a mechanism associated with CREB phosphorylation and ß-oxidation of fatty acids.