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.

Superoxide Dismutase Isoenzymes Gene Expression in Peripheral Blood Mononuclear Cells in Patients with Coronary Artery Disease

Background

Coronary artery disease (CAD) is one of the most important causes of mortality and morbidity in wide world population. Dyslipidemia, inflammation and oxidative stress may contribute to disruption of endothelium structure and function, atherosclerosis and CAD. Our study was aimed to determine whether Cu/Zn superoxide dismutase (Cu/Zn SOD) and Mn superoxide dismutase (Mn SOD) gene expression could be modulated by oxidative stress in CAD patients.

Methods

This study included 77 CAD patients and 31 apparently healthy persons. Serum lipid levels, high sensitivity C-reactive protein (hsCRP), total antioxidant status (TAS) and thiobarbituric acid-reacting substances (TBARS) were measured. SOD isoenzymes gene expression was determined in peripheral blood mononuclear cells using quantitative polymerase chain reaction.

Results

Mn SOD messenger ribonucleic acid (mRNA) levels were significantly lower in CAD patients than in controls (p=0.011), while Cu/Zn SOD mRNA levels did not change significantly between tested groups (p=0.091). We found significantly lower high-density lipoprotein-cholesterol (HDL-c) (p<0.001) and TAS (p<0.001) levels and significantly higher hsCRP (p=0.002) and TBARS (p<0.001) in CAD patients than in controls. There were significant positive correlations between TAS and Mn SOD mRNA (ρ=0.243, p=0.020) and TAS and Cu/Zn SOD mRNA (r=0.359, p<0.001). TBARS negatively correlated only with Cu/Zn SOD mRNA (ρ=-0.215, p=0.040). TAS levels remained independent predictor for Mn SOD mRNA levels (OR=2.995, p=0.034).

Conclusions

Results of this study showed that Mn SOD gene expression were decreased in CAD patients compared to controls and can be modulated by non-enzymatic antioxidant status in blood.

Overexpressing the Sedum alfredii Cu/Zn Superoxide Dismutase Increased Resistance to Oxidative Stress in Transgenic Arabidopsis

Superoxide dismutase (SOD) is a very important reactive oxygen species (ROS)-scavenging enzyme. In this study, the functions of a Cu/Zn SOD gene (SaCu/Zn SOD), from Sedum alfredii, a cadmium (Cd)/zinc/lead co-hyperaccumulator of the Crassulaceae, was characterized. The expression of SaCu/Zn SOD was induced by Cd stress. Compared with wild-type (WT) plants, overexpression of SaCu/Zn SOD gene in transgenic Arabidopsis plants enhanced the antioxidative defense capacity, including SOD and peroxidase activities. Additionally, it reduced the damage associated with the overproduction of hydrogen peroxide (H2O2) and superoxide radicals (O2•-). The influence of Cd stress on ion flux across the root surface showed that overexpressing SaCu/Zn SOD in transgenic Arabidopsis plants has greater Cd uptake capacity existed in roots. A co-expression network based on microarray data showed possible oxidative regulation in Arabidopsis after Cd-induced oxidative stress, suggesting that SaCu/Zn SOD may participate in this network and enhance ROS-scavenging capability under Cd stress. Taken together, these results suggest that overexpressing SaCu/Zn SOD increased oxidative stress resistance in transgenic Arabidopsis and provide useful information for understanding the role of SaCu/Zn SOD in response to abiotic stress.

TLR-7 agonist attenuates airway reactivity and inflammation through Nrf2-mediated antioxidant protection in a murine model of allergic asthma

Toll-like receptors (TLRs) through innate immune system recognize pathogen associated molecular patterns and play an important role in host defense against bacteria, fungi and viruses. TLR-7 is responsible for sensing single stranded nucleic acids of viruses but its activation has been shown to be protective in mouse models of asthma. The NADPH oxidase (NOX) enzymes family mainly produces reactive oxygen species (ROS) in the lung and is involved in regulation of airway inflammation in response to TLRs activation. However, NOX-4 mediated signaling in response to TLR-7 activation in a mouse model of allergic asthma has not been explored previously. Therefore, this study investigated the role TLR-7 activation and downstream oxidant-antioxidant signaling in a murine model of asthma. Mice were sensitized with ovalbumin (OVA) intraperitoneally and treated with TLR-7 agonist, resiquimod (RSQ) intranasally before each OVA challenge from days 14 to 16. Mice were then assessed for airway reactivity, inflammation, and NOX-4 and nuclear factor E2-related factor 2 (Nrf2) related signaling [inducible nitric oxide synthase (iNOS), nitrotyrosine, lipid peroxides and copper/zinc superoxide dismutase (Cu/Zn SOD)]. Treatment with RSQ reduced allergen induced airway reactivity and inflammation. This was paralleled by a decrease in ROS which was due to induction of Nrf2 and Cu/Zn SOD in RSQ treated group. Inhibition of MyD88 reversed RSQ-mediated protective effects on airway reactivity/inflammation due to reduction in Nrf2 signaling. SOD inhibition produced effects similar to MyD88 inhibition. The current study suggests that TLR-7 agonist is beneficial and may be developed into a therapeutic option in allergic asthma.

Nitric oxide triggers a concentration-dependent differential modulation of superoxide dismutase (FeSOD and Cu/ZnSOD) activity in sunflower seedling roots and cotyledons as an early and long distance signaling response to NaCl stress

Dark-grown sunflower (Helianthus annuus L.) seedlings exhibit modulation of total superoxide dismutase (SOD;EC 1.15.1.1) activity in roots and cotyledons (10,000g supernatant) in response to salt stress (NaCl; 120 mM) through a differential, zymographically detectable, whole tissue activity of FeSOD and Cu/ZnSOD. Confocal laser scanning microscopic imaging (CLSM) has further shown that NaCl stress significantly influences differential spatial distribution of Cu/ZnSOD and MnSOD isoforms in an inverse manner. Dual action of nitric oxide (NO) is evident in its crosstalk with FeSOD and Cu/ZnSOD in seedling roots and cotyledons in control and NaCl(-) stress conditions. Cu/ZnSOD activity in the roots of 2 d old NaCl(-) stressed seedlings is enhanced in the presence of 125-1000 µM of NO donor (sodium nitroprusside; SNP) indicating salt sensitivity of the enzyme activity. Quenching of endogenous NO by cPTIO treatment (500, 1000 µM) lowers FeSOD activity in roots (-NaCl). Cotyledons from control seedlings show an upregulation of FeSOD activity with increasing availability of SNP (125-1000 µM) in the Hoagland irrigation medium. Quenching of NO by cPTIO provides evidence for an inverse correlation between NO availability and FeSOD activity in seedling cotyledons irrespective of NaCl stress. Variable response due to NO on SOD isoforms in sunflower seedlings reflects its concentration-dependent biphasic (pro- and antioxidant) nature of action. Differential induction of SOD isoforms by NO indicates separate intracellular signaling pathways (associated with their respective functional separation) operative in seedling roots as an early salt stress mechanism and in cotyledons as an early long-distance NaCl stress sensing mechanism.

Reduced angiotensin II levels cause generalized vascular dysfunction via oxidant stress in hamster cheek pouch arterioles

OBJECTIVES

We investigated the effect of suppressing plasma angiotensin II (ANG II) levels on arteriolar relaxation in the hamster cheek pouch.

METHODS

Arteriolar diameters were measured via television microscopy during short-term (3-6days) high salt (HS; 4% NaCl) diet and angiotensin converting enzyme (ACE) inhibition with captopril (100mg/kg/day).

RESULTS

ACE inhibition and/or HS diet eliminated endothelium-dependent arteriolar dilation to acetylcholine, endothelium-independent dilation to the NO donor sodium nitroprusside, the prostacyclin analogs carbacyclin and iloprost, and the KATP channel opener cromakalim; and eliminated arteriolar constriction during KATP channel blockade with glibenclamide. Scavenging of superoxide radicals and low dose ANG II infusion (25ng/kg/min, subcutaneous) reduced oxidant stress and restored arteriolar dilation in arterioles of HS-fed hamsters. Vasoconstriction to topically-applied ANG II was unaffected by HS diet while arteriolar responses to elevation of superfusion solution PO2 were unaffected (5% O2, 10% O2) or reduced (21% O2) by HS diet.

CONCLUSIONS

These findings indicate that sustained exposure to low levels of circulating ANG II leads to widespread dysfunction in endothelium-dependent and independent vascular relaxation mechanisms in cheek pouch arterioles by increasing vascular oxidant stress, but does not potentiate O2- or ANG II-induced constriction of arterioles in the distal microcirculation of normotensive hamsters.

Increased Serum Cu/Zn SOD in Individuals with Clinical Depression Normalizes After Zinc and Anti-oxidant Therapy

AIM

To assess serum Cu/Zn SOD (Superoxide Dismutase) concentration in individuals with clinical depression.

SUBJECTS AND METHODS

Serum from 36 individuals diagnosed with clinical depression and 18 healthy controls were tested for Cu/Zn SOD serum concentration using ELISAs.

RESULTS

Serum Cu/Zn SOD levels of depressed individuals (both with and without secondary anxiety) were significantly higher than age and gender similar controls. We also found that, post anti-oxidant therapy, Cu/Zn SOD levels normalized to the level of normal healthy controls.

DISCUSSION

These results suggest an association between Cu/Zn SOD serum levels and clinical depression.

Decreased Serum Cu/Zn SOD Associated with High Copper in Children with Attention Deficit Hyperactivity Disorder (ADHD)

Aim

To assess serum Cu/Zn SOD (Superoxide Dismutase) concentration in children with ADHD and evaluate its possible relationship to Cu and Zn levels.

Subjects and methods

Serum from 22 children with ADHD and 20 healthy control children without ADHD and 19 autistic children without ADHD were tested for Cu/Zn SOD using ELISAs and levels of serum Cu and Zn using inductively-coupled plasma-mass spectrometry.

Results

Serum Cu/Zn SOD levels of ADHD children were significantly lower than age and gender matched healthy non-ADHD controls (P < 0.001). Serum Cu/Zn SOD of ADHD children was significantly lower in individuals with high serum copper (P = 0.024). There was no significant correlation between Cu/Zn SOD levels and Zinc or Cu/Zn in ADHD individuals.

Discussion

These results suggest an association between Cu/Zn SOD serum levels and ADHD, particularly ADHD children with high serum copper.

Purification and characterization of thermostable monomeric chloroplastic Cu/Zn superoxide dismutase from Chenopodium murale

Superoxide dismutase is the first line of defense against oxidative stress and thus helps in maintaining the cellular integrity. Chenopodium murale, a weed species adapted to widely varying climatic conditions faces extremes of temperatures ranging from 4 °C to 45 °C (Tmax) during growth and development. From this plant, we have purified a thermostable chloroplastic Cu/Zn superoxide dismutase (Chl Cu/Zn SOD) to homogeneity using minimal steps. Incubation of lysed chloroplasts at 70 °C for 1h reduced the interference of cytosolic SOD isoforms and reduced the protein content by 75 %. Chloroplastic SOD was purified from the heat stable fraction by gel filtration chromatography. The purified enzyme had a native molecular weight of 24 kDa, a half-life of 47.9 min at 80 °C and showed a single band at 24 kDa on SDS-PAGE. The N-terminus contained the conserved amino acids of chl Cu-Zn SOD. The Chl Cu/Zn SOD protein and its activity were enhanced under very high temperatures, high light intensities and in water stress/recovered C. murale plants under controlled environment conditions. Chl Cu/Zn SOD was also one of the predominant isoforms throughout growing period in field grown plants and declined during senescence. The Chl Cu/Zn SOD activity increased with the increase in ambient temperature and peaked in April with a 45 °C Tmax. These results clearly indicate that the chloroplastic Cu/Zn SOD is stably expressed at extreme environmental conditions. The presence of stable monomeric chloroplastic Cu/Zn SOD might help the plants to maintain the cellular homeostatis against adverse environmental conditions.