Manganese Superoxide Dismutase Activity Research Articles

Silver nanoparticle-induced cell damage via impaired mtROS-JNK/MnSOD signaling pathway

This study investigated the mechanism of silver nanoparticle (AgNP) cytotoxicity from a mitochondrial perspective. The effect of AgNP on manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant enzyme, against oxidative stress has not been studied in detail. We demonstrated that AgNP decreased MnSOD mRNA level, protein expression, and activity in human Chang liver cells in a time-dependent manner. AgNP induced the production of mitochondrial reactive oxygen species (mtROS), particularly superoxide anion. AgNP was found to increase mitochondrial calcium level and disrupt mitochondrial function, leading to reduced ATP level, succinate dehydrogenase activity, and mitochondrial permeability. AgNP induced cytochrome c release from the mitochondria into the cytoplasm, attenuated the expression of the anti-apoptotic proteins phospho Bcl-2 and Mcl-1, and induced the expression of the pro-apoptotic proteins Bim and Bax. In addition, c-Jun N-terminal kinase (JNK) phosphorylation was significantly increased by AgNP. Treatment with elamipretide (a mitochondria-targeted antioxidant) and SP600125 (a JNK inhibitor) showed the involvement of MnSOD and JNK in these processes. These results indicated that AgNP damaged human Chang liver cells by destroying mitochondrial function through the accumulation of mtROS.

Moringa oleifera fruit extract as a potential antioxidant against liver injury by 2-Nitropropane induction in obese male mice model: pre-clinical study

Background: Moringa oleifera fruit extract contains beneficial chemical compounds. This study was conducted to observed the power of antioxidant against liver injury by 2-Nitropropane induction in an obese male mice model. Methods: This research was in vivo laboratory experimental study with a post-test control design group only. The population was obese male mice models, Swiss strain, aged 6–8 weeks, weighing between 60–80 gr. The research sample was determined by Federer's formula for a complete randomized design experimental test, group N (control), O1 (induced by 2-Nitropropane intraperitoneal (i.p) once), O2 (induced by 2-Nitropropane i.p twice), P1 (induced by 2-Nitropropane i.p. once and gavage with M. oleifera fruit extract 500mg/kg bodyweight (BW) once a day), P2 (induced by 2-Nitropropane i.p. twice and gavage of M. oleifera fruit extract 500mg/kg BW once a day), and P3 (induced by 2-Nitropropane i.p. twice and gavage of vitamin C 500mg/kg BW once a day). Antioxidant potential parameters were measured by levels of malondialdehide (MDA), glutation (GSH), 8-hydroxy-2'-deoxyguanosine (8-OHdG), catalase activity, manganese superoxide dismutase (MnSOD), serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT). This research was held at the Biochemistry laboratory of Medicine Faculty, UPN Veteran Jakarta in May–September 2020. Analysis was carried out using SPSS version 20.0. The parameters were tested using ANOVA. Results: MDA levels decreased, GSH increased, 8-OHdG decreased, catalase activity increased, MnSOD activity increased and SGOT, SGPT levels decreased. M. oleifera fruit extract was statistically proven to be a candidate for potential antioxidant against liver injury of 2-Nitropropane induction in obese male mice model. Conclusions: M. oleifera fruit extract was statistically evident as an antioxidant substance that reduces oxidative stress in acute liver injury caused by 2-Nitropropane induction.

Hfe Permease and Haemophilus influenzae Manganese Homeostasis.

Haemophilus influenzae is a commensal of the human upper respiratory tract that can infect diverse host niches due, at least in part, to its ability to withstand both endogenous and host-mediated oxidative stresses. Here, we show that hfeA, a gene previously linked to iron import, is essential for H. influenzae manganese recruitment via the HfeBCD transporter. Structural analyses show that metal binding in HfeA uses a unique mechanism that involves substantial rotation of the C-terminal lobe of the protein. Disruption of hfeA reduced H. influenzae manganese acquisition and was associated with decreased growth under aerobic conditions, impaired manganese-superoxide dismutase activity, reduced survival in macrophages, and changes in biofilm production in the presence of superoxide. Collectively, this work shows that HfeA contributes to H. influenzae manganese acquisition and virulence attributes. High conservation of the hfeABCD permease in Haemophilus species suggests that it may serve similar roles in other pathogenic Pasteurellaceae.

Effects of Particulate Matter Inhalation during Exercise on Oxidative Stress and Mitochondrial Function in Mouse Skeletal Muscle.

Particulate matter (PM) has deleterious consequences not only on the respiratory system but also on essential human organs, such as the heart, blood vessels, kidneys, and liver. However, the effects of PM inhalation on skeletal muscles have yet to be sufficiently elucidated. Female C57BL/6 or mt-Keima transgenic mice were randomly assigned to one of the following four groups: control (CON), PM exposure alone (PM), treadmill exercise (EX), or PM exposure and exercise (PME). Mice in the three-treatment group were subjected to treadmill running (20 m/min, 90 min/day for 1 week) and/or exposure to PM (100 μg/m3). The PM was found to exacerbate oxidative stress and inflammation, both at rest and during exercise, as assessed by the levels of proinflammatory cytokines, manganese-superoxide dismutase activity, and the glutathione/oxidized glutathione ratio. Furthermore, we detected significant increases in the levels of in vivo mitophagy, particularly in the PM group. Compared with the EX group, a significant reduction in the level of mitochondrial DNA was recorded in the PME group. Moreover, PM resulted in a reduction in cytochrome c oxidase activity and an increase in hydrogen peroxide generation. However, exposure to PM had no significant effect on mitochondrial respiration. Collectively, our findings in this study indicate that PM has adverse effects concerning both oxidative stress and inflammatory responses in skeletal muscle and mitochondria, both at rest and during exercise.

β-Asarone Alleviates High-Glucose-Induced Oxidative Damage via Inhibition of ROS Generation and Inactivation of the NF-κB/NLRP3 Inflammasome Pathway in Human Retinal Pigment Epithelial Cells.

Diabetic retinopathy (DR) is the leading cause of vision loss and a major complication of diabetes. Hyperglycemia-induced accumulation of reactive oxygen species (ROS) is an important risk factor for DR. β-asarone, a major component of volatile oil extracted from Acori graminei Rhizoma, exerts antioxidant effects; however, its efficacy in DR remains unknown. In this study, we investigated whether β-asarone inhibits high-glucose (HG)-induced oxidative damage in human retinal pigment epithelial (RPE) ARPE-19 cells. We found that β-asarone significantly alleviated cytotoxicity, apoptosis, and DNA damage in HG-treated ARPE-19 cells via scavenging of ROS generation. β-Asarone also significantly attenuated the excessive accumulation of lactate dehydrogenase and mitochondrial ROS by increasing the manganese superoxide dismutase and glutathione activities. HG conditions markedly increased the release of interleukin (IL)-1β and IL-18 and upregulated their protein expression and activation of the nuclear factor-kappa B (NF-κB) signaling pathway, whereas β-asarone reversed these effects. Moreover, expression levels of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome multiprotein complex molecules, including thioredoxin-interacting protein, NLRP3, apoptosis-associated speck-like protein containing a caspase-recruitment domain, and cysteinyl aspartate-specific proteinase-1, were increased in ARPE-19 cells under HG conditions. However, their expression levels remained similar to those in the control group in the presence of β-asarone. Therefore, β-asarone protects RPE cells from HG-induced injury by blocking ROS generation and NF-κB/NLRP3 inflammasome activation, indicating its potential as a therapeutic agent for DR treatment.

Moringa oleifera fruit extract as a potential antioxidant against liver injury by 2-Nitropropane induction in obese male mice model: pre-clinical study

Background: Moringa oleifera fruit extract contains beneficial chemical compounds. This study was conducted to observed the power of antioxidant against liver injury by 2-Nitropropane induction in an obese male mice model. Methods: This research was in vivo laboratory experimental study with a post-test control design group only. The population was obese male mice models, Swiss strain, aged 6–8 weeks, weighing between 60–80 gr. The research sample was determined by Federer's formula for a complete randomized design experimental test, group N (control), O1 (induced by 2-Nitropropane intraperitoneal (i.p) once), O2 (induced by 2-Nitropropane i.p twice), P1 (induced by 2-Nitropropane i.p. once and gavage with M. oleifera fruit extract 500mg/kg bodyweight (BW) once a day), P2 (induced by 2-Nitropropane i.p. twice and gavage of M. oleifera fruit extract 500mg/kg BW once a day), and P3 (induced by 2-Nitropropane i.p. twice and gavage of vitamin C 500mg/kg BW once a day). Antioxidant potential parameters were measured by levels of malondialdehide (MDA), glutation (GSH), 8-hydroxy-2'-deoxyguanosine (8-OHdG), catalase activity, manganese superoxide dismutase (MnSOD), serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT). This research was held at the Biochemistry laboratory of Medicine Faculty, UPN Veteran Jakarta in May–September 2020. Analysis was carried out using SPSS version 20.0. The parameters were tested using ANOVA. Results: MDA levels decreased, GSH increased, 8-OHdG decreased, catalase activity increased, MnSOD activity increased and SGOT, SGPT levels decreased. M. oleifera fruit extract was statistically proven to be a candidate for potential antioxidant against liver injury of 2-Nitropropane induction in obese male mice model. Conclusions: M. oleifera fruit extract was statistically evident as an antioxidant substance that reduces oxidative stress in acute liver injury caused by 2-Nitropropane induction.

Mitochondrial oxidative damage by co-exposure to bisphenol A and acetaminophen in rat testes and its amelioration by melatonin.

Human exposure to multiple xenobiotics, over various developmental windows, results in adverse health effects arising from these concomitant exposures. Humans are widely exposed to bisphenol A, and acetaminophen is the most commonly used over-the-counter drug worldwide. Bisphenol A is a well-recognized male reproductive toxicant, and increasing evidence suggests that acetaminophen is also detrimental to the male reproductive system. The recent recognition of male reproductive system dysfunction in conditions of suboptimal reproductive outcomes makes it crucial to investigate the contributions of toxicant exposures to infertility and sub-fertility. We aimed to identify toxicity in the male reproductive system at the mitochondrial level in response to co-exposure to bisphenol A and acetaminophen, and we investigated whether melatonin ameliorated this toxicity. Male Wistar rats were divided into six groups (n=10 each): a control group and groups that received melatonin, bisphenol A, acetaminophen, bisphenol A and acetaminophen, and bisphenol A and acetaminophen with melatonin treatment. Significantly higher lipid peroxidation was observed in the testicular mitochondria and sperm in the treatment groups than in the control group. Levels of glutathione and the activities of catalase, glutathione peroxidase, glutathione reductase, and manganese superoxide dismutase decreased significantly in response to the toxicant treatments. Likewise, the toxicant treatments significantly decreased the sperm count and motility, while significantly increasing sperm mortality. Melatonin mitigated the adverse effects of bisphenol A and acetaminophen. Co-exposure to bisphenol A and acetaminophen elevated oxidative stress in the testicular mitochondria, and this effect was alleviated by melatonin.

Association of MnSOD Val16Ala (rs4880) Polymorphism with Staging, Grading, and Molecular Profile of Breast Cancer Patients at Prof. Dr. I.G.N.G. Ngoerah Hospital Denpasar Bali

Background: Aging is the major risk factor for breast cancer. Aging and breast cancer are interrelated due to the accumulation of reactive oxygen species (ROS). Manganese superoxide dismutase (MnSOD) has a pivotal role to defense ROS. The MnSOD Val16Ala (rs4880) polymorphism affects the activity of MnSOD in ROS detoxification. This study aims to prove the association of MnSOD Val16Ala (rs4880) polymorphism with stage, grading, and molecular profile of breast cancer patients at Prof. Dr. I.G.N.G. Ngoerah Hospital Denpasar Bali. Methods: This study used a cross-sectional exploratory descriptive method. It was conducted at the Integrated Biomedical Laboratory Unit of the Faculty of Medicine, Udayana University from September to November 2022. The samples used in this study were 45 biological materials in the form of DNA from breast cancer patients who were treated at the Oncology Unit of Prof. Dr. I.G.N.G. Ngoerah Hospital from 2016 to 2018 which is stored in the Biochemistry Laboratory of the Faculty of Medicine, Udayana University. The MnSOD Val16Ala (rs4880) polymorphism was examined by DNA amplification using polymerase chain reaction (PCR) method and the identification of the polymorphism by sequencing. The results obtained were analyzed using descriptive analysis with SPSS program. Results: The sequencing results found 45 samples (100%) with homozygous wild-type T/T. The association between MnSOD Val16Ala (rs4880) polymorphism and staging, grading, and molecular profile was unable to analyze. Conclusions: The MnSOD Val16Ala (rs4880) polymorphism was not found in breast cancer patient in Prof. Dr. I.G.N.G. Ngoerah hospital, Denpasar, Bali. Further research is needed to understand the role of MnSOD Val16Ala (rs4880) polymorphism with breast cancer risk. Keywords: superoxide dismutase enzyme, polymorphism, breast cancer

GAT107-mediated α7 nicotinic acetylcholine receptor signaling attenuates inflammatory lung injury and mortality in a mouse model of ventilator-associated pneumonia by alleviating macrophage mitochondrial oxidative stress via reducing MnSOD-S-glutathionylation

Supraphysiological concentrations of oxygen (hyperoxia) can compromise host defense and increase susceptibility to bacterial and viral infections, causing ventilator-associated pneumonia (VAP). Compromised host defense and inflammatory lung injury are mediated, in part, by high extracellular concentrations of HMGB1, which can be decreased by GTS-21, a partial agonist of α7 nicotinic acetylcholine receptor (α7nAChR). Here, we report that a novel α7nAChR agonistic positive allosteric modulator (ago-PAM), GAT107, at 3.3 mg/kg, i.p., significantly decreased animal mortality and markers of inflammatory injury in mice exposed to hyperoxia and subsequently infected with Pseudomonas aeruginosa. The incubation of macrophages with 3.3 μM of GAT107 significantly decreased hyperoxia-induced extracellular HMGB1 accumulation and HMGB1-induced macrophage phagocytic dysfunction. Hyperoxia-compromised macrophage function was correlated with impaired mitochondrial membrane integrity, increased superoxide levels, and decreased manganese superoxide dismutase (MnSOD) activity. This compromised MnSOD activity is due to a significant increase in its level of glutathionylation. The incubation of hyperoxic macrophages with 3.3 μM of GAT107 significantly decreases the levels of glutathionylated MnSOD, and restores MnSOD activity and mitochondrial membrane integrity. Thus, GAT107 restored hyperoxia-compromised phagocytic functions by decreasing HMGB1 release, most likely via a mitochondrial-directed pathway. Overall, our results suggest that GAT107 may be a potential treatment to decrease acute inflammatory lung injury by increasing host defense in patients with VAP.

Oral supplementation of a cell preparation of Enterococcus faecalis strain EC-12 stimulates superoxide dismutase production in the livers of healthy and arthritis-induced mice.

Hepatitis, a major human chronic inflammation disease, has been linked to oxidative stress, which can be initiated by radicals produced during the oxidative metabolism. Oxidative damage has been also observed in arthritis-induced mice. Here we evaluated whether supplementation of a cell preparation of Enterococcus faecalis EC-12 could induce superoxide dismutase activity and/or damage in the livers of healthy mice or mice with arthritis. In Experiment 1, both healthy and arthritis-induced mice were orally given a saline solution, or a solution with a low (0.2 mg/mouse/day) or a high (2.0 mg/mouse/day) concentration of E. faecalis EC-12 for 49 consecutive days. Manganese superoxide dismutase activity increased in E. faecalis EC-12-supplemented mice but with no arthritis. In Experiment 2, mice received orally either a saline or an E. faecalis EC-12 suspension (10 mg/kg of body weight/day) for 28 consecutive days. No changes in tissues and levels of function markers and 8-hydroxy-2'-deoxyguanosine were observed in mouse livers, inferring that E. faecalis EC-12 supplementation caused no damage. While mRNA expression of copper/zinc superoxide dismutase remained unaltered, that of manganese superoxide dismutase increased in E. faecalis EC-12 administration mice. In conclusion, at least in healthy mice, E. faecalis EC-12 supplementation stimulated manganese superoxide dismutase activity in liver tissues with no side effects.

2-Bromopalmitate decreases spinal inflammation and attenuates oxaliplatin-induced neuropathic pain via reducing Drp1-mediated mitochondrial dysfunction.

Oxaliplatin (OXA) is a third-generation platinum compound with clinical activity in multiple solid tumors. Due to the repetition of chemotherapy cycle, OXA-induced chronic neuropathy presenting as paresthesia and pain. This study explored the neuropathy of chemotherapy pain and investigated the analgesic effect of 2-bromopalmitate (2-BP) on the pain behavior of OXA-induced rats. The chemotherapy pain rat model was established by the five consecutive administration of OXA (intraperitoneal, 4 mg/kg). After the establishment of OXA-induced rats, the pain behavior test, inflammatory signal analysis and mitochondrial function measurement were conducted. OXA-induced rats exhibited mechanical allodynia and spinal inflammatory infiltration. Our fluorescence and western blot analysis revealed spinal astrocytes were activated in OXA rats with up-regulation of astrocytic markers. In addition, NOD-, LRR- and pyrin domain-containing 3 (NLRP3) inflammasome mediated inflammatory signal cascade was also activated. Inflammation was triggered by dysfunctional mitochondria which represented by increase in cyclooxygenase-2 (COX-2) level and manganese superoxide dismutase (Mn-SOD) activity. Intrathecally injection of 2-BP significantly attenuated dynamin-related protein 1 (Drp1) mediated mitochondrial fission, recovered mitochondrial function, suppressed NLRP3 inflammasome cascade, and consequently decreased mechanical pain sensitivity. For cell research, 2-BP treatment significantly reversed tumor necrosis factor-α (TNF-α) induced mitochondria membrane potential deficiency and high reactive oxygen species (ROS) level. These findings indicate 2-BP decreases spinal inflammation and relieves OXA-induced neuropathic pain via reducing Drp1-mediated mitochondrial dysfunction.

The effect of varying dietary manganese and selenium levels on the growth performance and manganese-superoxide dismutase activity in nursery pigs

Antioxidant activity in the weaned piglet is important for the developing animal at a cellular level. This study examined the impact of varying dietary levels of manganese and selenium on piglet growth performance and plasma manganese superoxide-dismutase (MnSOD) specific activity. Weaned piglets were blocked by weight (N = 216; 5.21 ± 1.17 kg; 21 ± 3 d) and sex (2 barrows and 2 gilts/pen). Pens (n = 9 pens/treatment) within a block were randomly assigned to dietary treatments in a 2 × 3 factorial design to examine the effect of adding different levels of Mn (0, 12, and 24 mg/kg added Mn from MnSO4 when pigs were fed diets containing 2 levels of Se (0.1 and 0.3 mg/kg added Se from Na2SeO3). Diets were fed in three phases (P1 = d 1–7, P2 = d 8–21, P3 = d 22–35). Pigs and orts were weighed weekly and blood collected on d 0, 7, 21, and 35 for analysis of red blood cell MnSOD. Data were analyzed via the GLM procedure of SAS. No Mn x Se interactions were observed. There was a linear response (P < 0.05) in overall average daily gain across dietary Mn levels. There was a linear trend (P < 0.10) in overall average daily feed intake across Mn levels. Gain to feed ratio (d 0–35) was not impacted by Mn or Se (P > 0.10). MnSOD activity in RBC increased from d 0–7, peaked at d 7, and decreased until d 35. On d 7, diets with 12 mg/kg Mn significantly increased (P < 0.05) MnSOD specific activity (0.91 IU/mg) compared to diets with 24 mg/kg Mn (0.67 IU/mg) but did not differ from diets with 0 mg/kg Mn (0.87 IU/mg). The dietary treatment that maintained specific MnSOD activity was 12 mg/kg Mn and 0.1 mg/kg Se supplemented, while ADG was maximized in diets with 24 mg/kg Mn supplemented.

Association between MnSOD Activity and Cognitive Impairment in Unmedicated First-Episode Schizophrenia: Regulated by MnSOD Ala-9Val Gene Polymorphism.

The imbalance between pro-oxidants and antioxidants is thought to be responsible for aging and cognitive impairment in many degenerative diseases, including schizophrenia (SZ). As the first antioxidant enzyme to detoxify superoxide radicals in mitochondria, manganese superoxide dismutase (MnSOD) activity and its functional polymorphism of Ala-9Val have been found to be associated with SZ. In this study, we explored the association between MnSOD activity, MnSOD Ala-9Val polymorphism and cognitive dysfunction in unmedicated first-episode (UMFE) SZ patients, which has not been examined. We recruited 234 UMFE SZ patients and 232 healthy controls (HC) and evaluated them with Repeated Battery for the Assessment of Neuropsychological Status (RBANS), plasma MnSOD activity and MnSOD Ala-9Val (rs4880) polymorphism. In addition, we used the Positive and Negative Syndrome Scale (PANSS) to assess the severity of patients’ psychopathological symptoms. Compared with HC, UMFE patients showed extensive cognitive impairment on RBANS, and had higher MnSOD activity. MnSOD Ala-9Val polymorphism was not associated with SZ susceptibility and cognitive impairment, but only affected MnSOD activity in patients. Moreover, only in SZ patients with Val homozygotes, MnSOD activity was significantly correlated with cognitive impairment, especially in RBANS total score, visuospatial/constructional and attention index scores. Our results suggest that cognitive impairment is associated with MnSOD activity in patients with first-episode SZ, which may be regulated by MnSOD Ala-9Val polymorphism.

Depletion of serum-derived exosomes aggravates heat stress-induced damage of bovine mammary epithelial cells.

Exosomes are involved in intercellular communication, affecting many physiological and pathological process. The present study evaluated the effects of serum exosomes on the function of bovine mammary epithelial cells (BMECs) and milk synthesis under heat stress. We cultured the BMECs in fetal bovine serum (FBS) or exosome-free FBS medium and examined, their viability using CCK-8 kit. The results showed that culturing the cells in an exosome-free medium decreased viability and increased the levels of reactive oxygen species. The BMECs cultured in the exosome-free medium had reduced mitochondrial membrane potential, decreased manganese superoxide dismutase activity, and disrupted mitochondrial dynamics. They exhibited apoptosis due to upregulated Drp1, Fis1, Bax and HSP70. Lastly, we observed downregulation of milk fat and lactoprotein-related genes: mTOR, PPARγ, p-mTOR and ADD1 and SREBP1, ELF5, and CSN2, respectively, after culturing the cells in an exosome-free medium. These negative effects of the exosome-free medium on the BMECs could be further reinforced under heat stress. Our results demonstrated that exosomes from serum are critical for maintaining the normal function of BMECs.

Punicalagin Protects against Diabetic Liver Injury by Upregulating Mitophagy and Antioxidant Enzyme Activities.

Diabetic liver injury has received increasing attention as a serious complication of type 2 diabetes. Punicalagin (PU), a major component of pomegranate polyphenols, has various biological activities such as antioxidant, anti-inflammatory, and lipid metabolism regulation. In this study, we observed the protective effect of punicalagin on a high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic liver injury in mice and revealed the underlying mechanism. The results showed that fasting blood glucose (FBG), fasting serum insulin (FINS), and homeostasis model assessment for insulin resistance (HOMA-IR) in diabetic liver injury mice were significantly decreased after punicalagin intervention. Simultaneously, the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), free fatty acids (FFA), malondialdehyde (MDA), and total superoxide dismutase (T-SOD) in the serum and liver were significantly decreased, with reductions in fat lesions and inflammatory cells. Mitophagy is a selective autophagy that maintains a balance between the quality and quantity of intracellular mitochondria. Studies have shown that mitophagy is closely related to the occurrence and development of diabetic liver injury. In our study, the mitochondrial membrane potential (MMP) was significantly increased in mice with diabetic liver injury after punicalagin intervention; the protein expression of Pink1, Parkin, Bnip3, LC3b, P62, manganese superoxide dismutase (MnSOD), and catalase (CAT) was significantly increased in the liver; and the activities of MnSOD and CAT in the serum and liver were significantly increased, which is consistent with the results of in vitro experiments. In summary, our study provided evidence that punicalagin could reduce the level of oxidative stress in the liver by upregulating mitophagy and the activities of antioxidant enzymes, thus having a certain protective effect against diabetic liver injury.

Antioxidant Capacity Is Decreased in Wilson's Disease and Correlates to Liver Function.

The metabolic disorder Wilson's disease (WD) is caused by copper accumulation in the tissues due to a biallelic pathogenic mutation of the gene ATP7B, encoding intracellular copper transporter ATPase-7B. As copper is a redox active metal; aberrations in its homeostasis may create favourable conditions for superoxide-yielding redox cycling and oxidative damage to the cells. We tried to characterise antioxidant defence in WD patients and to evaluate whether it is related to liver function.The blood glutathione concentration, the activity of manganese-SOD (MnSOD), catalase (Cat), glutathione peroxidase, and glutathione S-transferase glutathione (GST), and serum antioxidant potential (AOP-450) were measured in WD treatment-naive patients and healthy controls and correlated with clinical data.The blood glutathione concentration, the activity of MnSOD, Cat, glutathione peroxidase, and GST and AOP-450 are significantly decreased in WD patients. There was a positive correlation of AOP-450 with AST. Moreover, the Cat and GST activity as well as AOP-450 strongly correlated with parameters of synthetic liver function. MnSOD activity correlated positively with ALT and AST.The blood glutathione concentration, the activity of MnSOD, Cat, glutathione peroxidase, and GST and AOP-450 are significantly decreased in WD patients. There was a positive correlation of AOP-450 with AST. Moreover, the Cat and GST activity as well as AOP-450 strongly correlated with parameters of synthetic liver function. MnSOD activity correlated positively with ALT and AST.Liver injury in course of WD is linked with decreased antioxidant capacity.

Polydatin Attenuates Intra-Uterine Growth Retardation-Induced Liver Injury and Mitochondrial Dysfunction in Weanling Piglets by Improving Energy Metabolism and Redox Balance.

The present study investigated the potential of polydatin to protect against liver injury and the mitochondrial dysfunction of weanling piglets suffering from intra-uterine growth retardation (IUGR). Thirty-six normal birth weight weanling piglets and an equal number of IUGR littermates were given a basal diet with or without polydatin (250 mg/kg) from 21 to 35 d of age. Plasma and liver samples were collected to measure biochemistry parameters at 35 d of age. IUGR caused hepatic apoptosis, mitochondrial dysfunction, and oxidative damage, along with a lower efficiency of energy metabolism and inferior antioxidant ability. Polydatin decreased apoptotic rate, improved the features of mitochondrial damage, inhibited mitochondrial swelling and superoxide anion formation, and preserved mitochondrial membrane potential in the liver. Concurrently, polydatin promoted mitochondrial biogenesis, increased sirtuin 1 activity, and upregulated the expression levels of several genes related to mitochondrial function and fitness. Polydatin also facilitated mitochondrial oxidative metabolism with a beneficial outcome of increased energy production. Furthermore, polydatin mitigated the IUGR-induced reduction in manganese superoxide dismutase activity and prevented the excessive accumulation of oxidative damaging products in the liver. These findings indicate that polydatin confers protection against hepatic injury and mitochondrial dysfunction in the IUGR piglets by improving energy metabolism and redox balance.

Impacts of Mn, Fe, and Oxidative Stressors on MnSOD Activation by AtMTM1 and AtMTM2 in Arabidopsis.

It has been reported that the mitochondrial carrier family proteins of AtMTM1 and AtMTM2 are necessary for manganese superoxide dismutase (MnSOD) activation in Arabidopsis, and are responsive to methyl viologen (MV)-induced oxidative stress. In this study, we showed that MnSOD activity was enhanced specifically by Mn treatments. By using AtMnSOD-overexpressing and AtMnSOD-knockdown mutant plants treated with the widely used oxidative stressors including MV, NaCl, H2O2, and tert-butyl hydroperoxide (t-BH), we revealed that Arabidopsis MnSOD was crucial for root-growth control and superoxide scavenging ability. In addition, it has been reported that E. coli MnSOD activity is inhibited by Fe and that MTM1-mutated yeast cells exhibit elevated Fe content and decreased MnSOD activity, which can be restored by the Fe2+-specific chelator, bathophenanthroline disulfonate (BPS). However, we showed that BPS inhibited MnSOD activity in AtMTM1 and AtMTM2 single- and double-mutant protoplasts, implying that altered Fe homeostasis affected MnSOD activation through AtMTM1 and AtMTM2. Notably, we used inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis to reveal an abnormal Fe/Mn ratio in the roots and shoots of AtMTM1 and AtMTM2 mutants under MV stress, indicating the importance of AtMTM1 in roots and AtMTM2 in shoots for maintaining Fe/Mn balance.

MnSOD functions as a thermoreceptor activated by low temperature

A conservative characteristic of manganese superoxide dismutase is the rapid formation of product inhibition at high temperatures. At lower temperatures, the enzyme is less inhibited and undergoes more catalytic fast cycles before being product-inhibited. The temperature-dependent kinetics could be rationalized by the temperature-dependent coordination in the conserved center of manganese superoxide dismutase. As temperature decreases, a water molecule (WAT2) approaches or even coordinates Mn as the sixth ligand to interfere with O2•--Mn coordination and reduce product inhibition, so the dismutation should mainly proceed in the fast outer-sphere pathway at low temperatures. Cold-activation is an adaptive response to low temperature rather than a passive adaptation to excess superoxide levels since the cold-activated dismutase activity significantly exceeds the amount of superoxide in the cell or mitochondria. Physiologically speaking, cold activation of manganese superoxide dismutase mediates cold stress signaling and transduces temperature (physical signal) degree into H2O2 fluxes (chemical signal), which in turn may act as a second messenger to induce a series of physiological responses such as cold shock.

The relationship between cognitive impairment and superoxide dismutase activity in untreated first-episode patients with schizophrenia

Objectives : Cognitive decline is an essential characteristic of schizophrenia and may be due to the disturbance between reactive oxygen species generation and antioxidant capacity. The study aimed to explore the association between cognitive deficits and antioxidant defence parameters in untreated first-episode patients with schizophrenia. Methods : We determined important antioxidant enzymes, total superoxide dismutase (SOD) and manganese SOD (MnSOD), and their relationship with cognitive impairment in 168 untreated patients with first-episode schizophrenia and 168 age- and sex-matched healthy controls. The evaluation of psychopathological symptoms of all patients was based on the Positive and Negative Syndrome Scale (PANSS). We measured cognitive function by the Repeated Battery for the Assessment of Neuropsychological Status (RBANS) and activities of total SOD and MnSOD in all participants. Results : The results showed that untreated patients with first-episode schizophrenia had deficient cognitive functioning in four RBANS indices and total scores, except for the visuospatial/constructional index, as well as higher plasma total SOD activity compared with the control subjects. In addition, significant negative correlations were identified between MnSOD activity and attention index or RBANS total score in patients. Conclusions : Our results suggest that oxidative stress may be partly responsible for cognitive dysfunction in the early course of schizophrenia.