The MMP-9 promoter genetic variant rs3918242, mRNA and protein expression in advanced carotid plaque tissue.

BACKGROUND: The MMP-9 is a known player in atherosclerosis, yet associations of the MMP-9 -1562 C/T variant (rs3918242) with various atherosclerotic phenotypes and tissue mRNA expression are still contradictory. This study aimed to investigate the MMP-9 -1562 C/T variant, its mRNA and protein expression in carotid plaque (CP) tissue, as a risk factor for CP presence and as a marker of different plaque phenotypes (hyperechoic and hypoechoic) in patients undergoing carotid endarterectomy. The MnSOD as an MMP-9 negative regulator was also studied in relation to CP phenotypes. METHODS AND RESULTS: Genotyping of 770 participants (285 controls/485 patients) was done by tetra-primer ARMS PCR. The MMP-9 mRNA expression in 88 human CP tissues was detected by TaqMan® technology. The protein levels of MMP-9 and MnSOD were assessed by Western blot analysis. The MMP-9 -1562 C/T variant was not recognized as a risk factor for plaque presence or in predisposing MMP-9 mRNA and protein levels in plaque tissue. Patients with hypoechoic plaques had significantly lower MMP-9 mRNA and protein levels than those with hyperechoic plaque (p = 0.008, p = 0.003, respectively). MnSOD protein level was significantly higher in hypoechoic plaque compared to hyperechoic (p = 0.039). MMP-9 protein expression in CP tissue was significantly affected by sex and plaque type interaction (p = 0.009). CONCLUSIONS: Considering the differences of MMP-9 mRNA and protein expression in CP tissue regarding different plaque phenotypes and the observed sex-specific effect, the role of MMP-9 in human atherosclerotic plaques should be further elucidated.

Association of MnSOD, CAT, and GPx1 Gene Polymorphism with Risk of Diabetic Nephropathy in South Indian Patients: A Case-Control Study.

Diabetic nephropathy (DN) is one of the common complications of type 2 diabetes mellitus (T2DM), and oxidative stress plays a key role in the pathogenesis of DN. Studies have demonstrated that antioxidants (MnSOD, CAT, and GPx1) may reduce the complications associated with T2DM. The purpose of the study is to correlate the role of antioxidant gene polymorphisms in the pathogenesis of DN among T2DM individuals in the South Indian population. It clarifies the importance of early manifestation and reliable genetic indicators modulating the oxidative stress mechanism in DN. The study participants were divided and grouped as Group 1: Control, Group 2: T2DM without DN, and Group 3: T2DM with DN (n = 100 in each group). The levels of plasma glucose, HbA1c, renal profile, SOD, CAT, GPx1, MDA, and TAS were assessed. MnSOD (rs4880), CAT (rs1049982), and GPx1 (rs1050450) polymorphisms were genotyped via Tetra-arms PCR. The genotypes of GPx1 depict a significant role in the progression of DN in T2DM patients (co-dominant [OR: 2.134; 95% CI (1.202-3.788), p < 0.01], dominant [OR: 2.015; 95% CI (1.117-3.634), p = 0.02], and recessive model [OR: 2.215; 95% CI (1.235-3.972), p = 0.008]); whereas rs4880 and rs1049982 polymorphisms are not associated with DN progression. As a result, GPx1 (rs1050450) polymorphism could be a diagnostic risk factor for developing DN in T2DM patients. Moreover, the genotypes of rs4880 and rs1049982 polymorphism show significant difference in the antioxidant parameters compared to the genotypes of rs1050450. In contradiction to earlier studies, the current study demonstrates that the genotypes of rs1050450 (GPx1) can be considered as an influential component for higher susceptibility and risk of developing DN in T2DM patients among the South Indian population.

Disclosing the Novel Protective Mechanisms of Ocrelizumab in Multiple Sclerosis: The Role of PKC Beta and Its Down-Stream Targets.

Ocrelizumab (OCR) is a humanized anti-CD20 monoclonal antibody approved for both Relapsing and Primary Progressive forms of Multiple Sclerosis (MS) treatment. OCR is postulated to act via rapid B cell depletion; however, by analogy with other anti-CD20 agents, additional effects can be envisaged, such as on Protein Kinase C (PKC). Hence, this work aims to explore novel potential mechanisms of action of OCR in peripheral blood mononuclear cells from MS patients before and after 12 months of OCR treatment. We first assessed, up-stream, PKCßII and subsequently explored two down-stream pathways: hypoxia-inducible factor 1 alpha (HIF-1α)/vascular endothelial growth factor (VEGF), and human antigen R (HuR)/manganese-dependent superoxide dismutase (MnSOD) and heat shock proteins 70 (HSP70). At baseline, higher levels of PKCßII, HIF-1α, and VEGF were found in MS patients compared to healthy controls (HC); interestingly, the overexpression of this inflammatory cascade was counteracted by OCR treatment. Conversely, at baseline, the content of HuR, MnSOD, and HSP70 was significantly lower in MS patients compared to HC, while OCR administration induced the up-regulation of these neuroprotective pathways. These results enable us to disclose the dual positive action of OCR: anti-inflammatory and neuroprotective. Therefore, in addition to B cell depletion, the effect of OCR on these molecular cascades can contribute to counteracting disease progression.

Manganese- and Platinum-Driven Oxidative and Nitrosative Stress in Oxaliplatin-Associated CIPN with Special Reference to Ca4Mn(DPDP)5, MnDPDP and DPDP.

Platinum-containing chemotherapeutic drugs are efficacious in many forms of cancer but are dose-restricted by serious side effects, of which peripheral neuropathy induced by oxidative-nitrosative-stress-mediated chain reactions is most disturbing. Recently, hope has been raised regarding the catalytic antioxidants mangafodipir (MnDPDP) and calmangafodipir [Ca4Mn(DPDP)5; PledOx®], which by mimicking mitochondrial manganese superoxide dismutase (MnSOD) may be expected to overcome oxaliplatin-associated chemotherapy-induced peripheral neuropathy (CIPN). Unfortunately, two recent phase III studies (POLAR A and M trials) applying Ca4Mn(DPDP)5 in colorectal cancer (CRC) patients receiving multiple cycles of FOLFOX6 (5-FU + oxaliplatin) failed to demonstrate efficacy. Instead of an anticipated 50% reduction in the incidence of CIPN in patients co-treated with Ca4Mn(DPDP)5, a statistically significant increase of about 50% was seen. The current article deals with confusing differences between early and positive findings with MnDPDP in comparison to the recent findings with Ca4Mn(DPDP)5. The POLAR failure may also reveal important mechanisms behind oxaliplatin-associated CIPN itself. Thus, exacerbated neurotoxicity in patients receiving Ca4Mn(DPDP)5 may be explained by redox interactions between Pt2+ and Mn2+ and subtle oxidative-nitrosative chain reactions. In peripheral sensory nerves, Pt2+ presumably leads to oxidation of the Mn2+ from Ca4Mn(DPDP)5 as well as from Mn2+ in MnSOD and other endogenous sources. Thereafter, Mn3+ may be oxidized by peroxynitrite (ONOO-) into Mn4+, which drives site-specific nitration of tyrosine (Tyr) 34 in the MnSOD enzyme. Conformational changes of MnSOD then lead to the closure of the superoxide (O2•-) access channel. A similar metal-driven nitration of Tyr74 in cytochrome c will cause an irreversible disruption of electron transport. Altogether, these events may uncover important steps in the mechanism behind Pt2+-associated CIPN. There is little doubt that the efficacy of MnDPDP and its therapeutic improved counterpart Ca4Mn(DPDP)5 mainly depends on their MnSOD-mimetic activity when it comes to their potential use as rescue medicines during, e.g., acute myocardial infarction. However, pharmacokinetic considerations suggest that the efficacy of MnDPDP on Pt2+-associated neurotoxicity depends on another action of this drug. Electron paramagnetic resonance (EPR) studies have demonstrated that Pt2+ outcompetes Mn2+ and endogenous Zn2+ in binding to fodipir (DPDP), hence suggesting that the previously reported protective efficacy of MnDPDP against CIPN is a result of chelation and elimination of Pt2+ by DPDP, which in turn suggests that Mn2+ is unnecessary for efficacy when it comes to oxaliplatin-associated CIPN.

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.

Hippocampus mitochondrial MnSOD activation by a SIRT3 activator, honokiol, correlates with its deacetylation and upregulation of FoxO3a and PGC1α in a rat model of ammonia neurotoxicity.

We have recently reported that honokiol (HKL), by activating mitochondrial SIRT3, normalizes reactive oxygen species level and mitochondrial integrity in hippocampus of the moderate grade hepatic encephalopathy (MoHE) rat model of ammonia neurotoxicity. To delineate the mechanism by which HKL does so, the present study describes activity versus level of the deacetylated mitochondrial Mn-superoxide dismutase (MnSOD) and expression of MnSOD versus levels of its main transcription regulators, FoxO3a and PGC1α, in the hippocampus of the MoHE rats. MoHE in rat was developed by administration of 100 mg/kg bw thioacetamide i.p. for 10 days. The study parameters were compared between the control, the MoHE rats and the MoHE rats treated with HKL (10 mg/Kg b.w.) for 7 days. As compared to control, the hippocampus mitochondria from MoHE rats showed a significantly declined activity of MnSOD vs enhanced lipid peroxidation coinciding with the increased level of its acetylated form. The HKL treatment could, however, normalize all these parameters in those MoHE rats. Also, a significantly reduced expression of MnSOD in the hippocampus of the MoHE rats coincided with a similar decline in transcript level of Foxo3a and Pgc1α. This was consistent with the reduced level of immuno-stained Foxo3a and Pgc1α proteins in hippocampus DG, CA1 and CA3 regions of those MoHE rats. However, all these factors were observed to be restored back to their normal levels due to the treatment with HKL. As HKL is a specific activator of mitochondrial SIRT3, these findings suggest involvement of Sirt3 activation led deacetylation of MnSOD and upregulation of its transcription activators, FoxO3a and PGC1α, in restoring mitochondrial MnSOD level in the hippocampus of the MoHE rat model of ammonia neurotoxicity.

Reduction in mitochondrial ROS improves oxidative phosphorylation and provides resilience to coronary endothelium in non-reperfused myocardial infarction.

Recent studies demonstrated that mitochondrial antioxidant MnSOD that reduces mitochondrial (mito) reactive oxygen species (ROS) helps maintain an optimal balance between sub-cellular ROS levels in coronary vascular endothelial cells (ECs). However, it is not known whether EC-specific mito-ROS modulation provides resilience to coronary ECs after a non-reperfused acute myocardial infarction (MI). This study examined whether a reduction in endothelium-specific mito-ROS improves the survival and proliferation of coronary ECs in vivo. We generated a novel conditional binary transgenic animal model that overexpresses (OE) mitochondrial antioxidant MnSOD in an EC-specific manner (MnSOD-OE). EC-specific MnSOD-OE was validated in heart sections and mouse heart ECs (MHECs). Mitosox and mito-roGFP assays demonstrated that MnSOD-OE resulted in a 50% reduction in mito-ROS in MHEC. Control and MnSOD-OE mice were subject to non-reperfusion MI surgery, echocardiography, and heart harvest. In post-MI hearts, MnSOD-OE promoted EC proliferation (by 2.4 ± 0.9 fold) and coronary angiogenesis (by 3.4 ± 0.9 fold), reduced myocardial infarct size (by 27%), and improved left ventricle ejection fraction (by 16%) and fractional shortening (by 20%). Interestingly, proteomic and Western blot analyses demonstrated upregulation in mitochondrial complex I and oxidative phosphorylation (OXPHOS) proteins in MnSOD-OE MHECs. These MHECs also showed increased mitochondrial oxygen consumption rate (OCR) and membrane potential. These findings suggest that mito-ROS reduction in EC improves coronary angiogenesis and cardiac function in non-reperfused MI, which are associated with increased activation of OXPHOS in EC-mitochondria. Activation of an energy-efficient mechanism in EC may be a novel mechanism to confer resilience to coronary EC during MI.

Antioxidant and drought-acclimation responses in UV-B-exposed transgenic Nicotiana tabacum displaying constitutive overproduction of H2O2.

Hydrogen peroxide (H2O2) is an important molecule that regulates antioxidant responses that are crucial for plant stress resistance. Exposure to low levels of ultraviolet-B radiation (UV-B, 280-315 nm) can also activate antioxidant defenses and acclimation responses. However, how H2O2 and UV-B interact to promote stress acclimation remains poorly understood. In this work, a transgenic model of Nicotiana tabacum cv Xanthi nc, with elevated Mn-superoxide dismutase (Mn-SOD) activity, was used to study the interaction between the constitutive overproduction of H2O2 and a 14-day UV-B treatment (1.75 kJ m-2 d-1 biologically effective UV-B). Subsequently, these plants were subjected to a 7-day moderate drought treatment to evaluate the impact on drought resistance of H2O2- and UV-dependent stimulation of the plants' antioxidant system. The UV-B treatment enhanced H2O2 levels and altered the antioxidant status by increasing the epidermal flavonol index, Trolox Equivalent Antioxidant Capacity, and catalase, peroxidase and phenylalanine ammonia lyase activities in the leaves. UV-B also retarded growth and suppressed acclimation responses in highly H2O2-overproducing transgenic plants. Plants not exposed to UV-B had a higher drought resistance in the form of higher relative water content of leaves. Our data associate the interaction between Mn-SOD transgene overexpression and the UV-B treatment with a stress response. Finally, we propose a hormetic biphasic drought resistance response curve as a function of leaf H2O2 content in N. tabacum cv Xanthi.

MCD Diet Modulates HuR and Oxidative Stress-Related HuR Targets in Rats.

The endogenous antioxidant defense plays a big part in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), a common metabolic disorder that can lead to serious complications such as cirrhosis and cancer. HuR, an RNA-binding protein of the ELAV family, controls, among others, the stability of MnSOD and HO-1 mRNA. These two enzymes protect the liver cells from oxidative damage caused by excessive fat accumulation. Our aim was to investigate the expression of HuR and its targets in a methionine-choline deficient (MCD) model of NAFLD. To this aim, we fed male Wistar rats with an MCD diet for 3 and 6 weeks to induce NAFLD; then, we evaluated the expression of HuR, MnSOD, and HO-1. The MCD diet induced fat accumulation, hepatic injury, oxidative stress, and mitochondrial dysfunction. A HuR downregulation was also observed in association with a reduced expression of MnSOD and HO-1. Moreover, the changes in the expression of HuR and its targets were significantly correlated with oxidative stress and mitochondrial injury. Since HuR plays a protective role against oxidative stress, targeting this protein could be a therapeutic strategy to both prevent and counteract NAFLD.

Interferon Gamma Enhances Cytoprotective Pathways via Nrf2 and MnSOD Induction in Friedreich's Ataxia Cells.

Friedreich's ataxia (FRDA) is a rare monogenic disease characterized by multisystem, slowly progressive degeneration. Because of the genetic defect in a non-coding region of FXN gene, FRDA cells exhibit severe deficit of frataxin protein levels. Hence, FRDA pathophysiology is characterized by a plethora of metabolic disruptions related to iron metabolism, mitochondrial homeostasis and oxidative stress. Importantly, an impairment of the antioxidant defences exacerbates the oxidative damage. This appears closely associated with the disablement of key antioxidant proteins, such as the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and the mitochondrial superoxide dismutase (MnSOD). The cytokine interferon gamma (IFN-γ) has been shown to increase frataxin expression in FRDA cells and to improve functional deficits in FRDA mice. Currently, IFN-γ represents a potential therapy under clinical evaluation in FRDA patients. Here, we show that IFN-γ induces a rapid expression of Nrf2 and MnSOD in different cell types, including FRDA patient-derived fibroblasts. Our data indicate that IFN-γ signals two separate pathways to enhance Nrf2 and MnSOD levels in FRDA fibroblasts. MnSOD expression increased through an early transcriptional regulation, whereas the levels of Nrf2 are induced by a post-transcriptional mechanism. We demonstrate that the treatment of FRDA fibroblasts with IFN-γ stimulates a non-canonical Nrf2 activation pathway through p21 and potentiates antioxidant responses under exposure to hydrogen peroxide. Moreover, IFN-γ significantly reduced the sensitivity to hydrogen peroxide-induced cell death in FRDA fibroblasts. Collectively, these results indicate the presence of multiple pathways triggered by IFN-γ with therapeutic relevance to FRDA.

Genetic polymorphism impact superoxide dismutase and glutathione peroxidase activity in charcoal workers.

BACKGROUND: Incomplete combustion of wood releases toxic chemicals. Exposure to these chemicals during charcoal production can modulate redox status of cellular system which may further lead to genomic instability and of antioxidant enzymes. Genetic polymorphism may alter the functioning properties of these enzymes and modulate the response to oxidative stress. METHODS: In this study, we analyzed the link between genetic polymorphism and enzyme activity for antioxidant enzymes: MnSOD and GPx-1 in charcoal workers and control population. This study included 77 charcoal workers and 79 demographically matched healthy control subjects. This association was studied using multiple linear regression, adjusted for confounding factors viz. age, consumption habits and exposure duration. RESULTS: SOD activity was lower for TT genotype (3.47 ± 0.66; 5.92 ± 1.08) versus CC genotype (3.47 ± 0.66; 6.67 ± 1.60) in control and charcoal workers respectively. Significant lower GPx-1 activity was found in leu/leu genotype (7.25 ± 0.38; 3.59 ± 0.57) when compared to pro/pro genotype (7.78 ± 0.59; 4.28 ± 0.71) and pro/leu genotype (8.48 ± 0.34; 4.30 ± 0.76) in control population and charcoal workers respectively. A significant difference in the levels of 1-Hydroxypyrene (biomarker of exposure) and SOD and GPx-1 activity (biomarkers of oxidative stress) was evident in exposed group in comparison to the control one. CONCLUSION: Collectively, our findings suggested that PAH influenced the mode of action of SOD and GPx-1 which were impacted by polymorphism in SOD and GPx-1 gene. Hence, polymorphism of MnSOD and GPx-1 genes were found to play a modulatory role in human susceptibility to oxidative damage induced by wood smoke in charcoal workers.

SOD2 acetylation on lysine 68 promotes stem cell reprogramming in breast cancer.

Mitochondrial superoxide dismutase (SOD2) suppresses tumor initiation but promotes invasion and dissemination of tumor cells at later stages of the disease. The mechanism of this functional switch remains poorly defined. Our results indicate that as SOD2 expression increases acetylation of lysine 68 ensues. Acetylated SOD2 promotes hypoxic signaling via increased mitochondrial reactive oxygen species (mtROS). mtROS, in turn, stabilize hypoxia-induced factor 2α (HIF2α), a transcription factor upstream of "stemness" genes such as Oct4, Sox2, and Nanog. In this sense, our findings indicate that SOD2K68Ac and mtROS are linked to stemness reprogramming in breast cancer cells via HIF2α signaling. Based on these findings we propose that, as tumors evolve, the accumulation of SOD2K68Ac turns on a mitochondrial pathway to stemness that depends on HIF2α and may be relevant for the progression of breast cancer toward poor outcomes.

Insights into Manganese Superoxide Dismutase and Human Diseases.

Redox equilibria and the modulation of redox signalling play crucial roles in physiological processes. Overproduction of reactive oxygen species (ROS) disrupts the body's antioxidant defence, compromising redox homeostasis and increasing oxidative stress, leading to the development of several diseases. Manganese superoxide dismutase (MnSOD) is a principal antioxidant enzyme that protects cells from oxidative damage by converting superoxide anion radicals to hydrogen peroxide and oxygen in mitochondria. Systematic studies have demonstrated that MnSOD plays an indispensable role in multiple diseases. This review focuses on preclinical evidence that describes the mechanisms of MnSOD in diseases accompanied with an imbalanced redox status, including fibrotic diseases, inflammation, diabetes, vascular diseases, neurodegenerative diseases, and cancer. The potential therapeutic effects of MnSOD activators and MnSOD mimetics are also discussed. Targeting this specific superoxide anion radical scavenger may be a clinically beneficial strategy, and understanding the therapeutic role of MnSOD may provide a positive insight into preventing and treating related diseases.

Potential Application of Leelamine as a Novel Regulator of Chemokine-Induced Epithelial-to-Mesenchymal Transition in Breast Cancer Cells.

CXCR7 and CXCR4 are G protein-coupled receptors (GPCRs) that can be stimulated by CXCL12 in various human cancers. CXCR7/4-CXCL12 binding can initiate activation of multiple pathways including JAK/STAT and manganese superoxide dismutase (MnSOD) signaling, and initiate epithelial-mesenchymal transition (EMT) process. It is established that cancer cell invasion and migration are caused because of these events. In particular, the EMT process is an important process that can determine the prognosis for cancer. Since the antitumor effect of leelamine (LEE) has been reported in various previous studies, here, we have evaluated the influence of LEE on the CXCR7/4 signaling axis and EMT processes. We first found that LEE suppressed expression of CXCR7 and CXCR4 both at the protein and mRNA levels, and showed inhibitory effects on these chemokines even after stimulation by CXCL12 ligand. In addition, LEE also reduced the level of MnSOD and inhibited the EMT process to attenuate the invasion and migration of breast cancer cells. In addition, phosphorylation of the JAK/STAT pathway, which acts down-stream of these chemokines, was also abrogated by LEE. It was also confirmed that LEE can induce an imbalance of GSH/GSSG and increases ROS, thereby resulting in antitumor activity. Thus, we establish that targeting CXCR7/4 in breast cancer cells can not only inhibit the invasion and migration of cancer cells but also can affect JAK/STAT, EMT process, and production of ROS. Overall, the findings suggest that LEE can function as a novel agent affecting the breast cancer.

Angiopoietin-Like Protein 4 Is Involved in Manganese Superoxide Dismutase-Mediated Suppression of Breast Cancer Cell Growth.

This study aims to understand the molecular basis of manganese superoxide dismutase (MnSOD) impacts on breast cancer cell growth. Modulation of the level of MnSOD by genetic engineering led significant changes in the expression of angiopoietin-like protein 4 (ANGPTL4) and activity of peroxisome proliferator-activated receptor α (PPARα) in MCF7 cells. PPARα agonist increased ANGPTL4 expression inhibited by MnSOD. Proliferation of MCF7 cells was inhibited by MnSOD, however, ANGPTL4 transduction into MCF7 cells with MnSOD overexpression significantly stimulated cell proliferation. MnSOD induced G0/G1 cell cycle arrest, nevertheless, ANGPTL4 transduction significantly reduced the percentage of cells in G0/G1 phase overexpressing MnSOD. In conclusion, MnSOD suppressed the expression of ANGPTL4 in breast cancer cells via the PPARα signaling pathway, and ANGPTL4 was involved in MnSOD-mediated proliferation inhibition and cell cycle arrest.

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

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

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.

Molecular and functional characterization of mitochondrial manganese superoxide dismutase from Macrobrachium rosenbergii during bacterial infection.

Superoxide dismutases (SODs) are the main antioxidant enzymes involved in alleviating oxidative stress. Although mitochondrial manganese SOD (mMnSOD) has been reported to be correlated with the immune response in crustaceans, its biological properties and role in the immune response remain unclear. Here, we cloned the Macrobrachium rosenbergii mMnSOD (MrmMnSOD), analyzed its activity and expression pattern under Staphylococcus aureus and Vibrio parahaemolyticus infection, and further explored its possible mechanism during antibacterial immune response. The results showed that both enzyme activity and the expression of MrmMnSOD were significantly up-regulated by bacterial infection. MrmMnSOD knockdown made the prawn susceptible to Vibrio infection, which increased the mortality rate and the number of bacteria in haemocytes. The bacterial agglutination assay confirmed that MrmMnSOD decreases bacterial abundance via agglutination. Overall, this work identified antibacterial function of MrmMnSOD in the immune response. In addition to contributing to immunological theory, these findings aid disease prevention and control in crustacean aquaculture.

Cloning of Mn-SOD gene and its mRNA expression difference and antioxidant enzyme activities under hypoxia stress of cobia Rachycentron canadum.

BACKGROUND: Environmental hypoxia affects the survival and development of organisms. It is also an important environmental factor that leads to oxidative damage. Hypoxia is a condition in which tissues are deprived of oxygen; reoxygenation is the phenomenon in which hypoxic tissues are exposed to oxygen. Hypoxia-reoxygenation is vital in pathogenesis, where the production of reactive oxygen species and antioxidant disparity significantly contribute to disease progression, and it is one of the most common physiological stressors in the aquaculture industry. METHODS AND RESULTS: In this study, the full length of complementary DNA (cDNA) of the manganese superoxide dismutase (Mn-SOD) gene of healthy cobia Rachycentron canadum was analysed using rapid amplification of cDNA ends. The real-time quantitative Polymerase Chain Reaction was used to measure the expression levels of Mn-SOD mRNAs in various tissues (heart, muscle, brain, liver, kidney, gill, intestine, and spleen). The 2-ΔΔCT method was used to performed the expression analysis. The experimental data were analysed using SPSS ver. 19.0 ( https://spss.software.informer.com/19.0/ ). P < 0.05 and P < 0.01 were set as significant differences. The values were articulated as mean ± standard deviation. The Mn-SOD gene cDNA sequence was 1209 bp long, including a 684 bp open reading frame, 42 bp 5'UTR and 483 bp 3'UTR, encoding 227 amino acids. Under hypoxia-reoxygen stress, the expression of Mn-SOD in brain tissue was significantly lower than in the control group after 8 h of reoxygenation and higher than the control group after 24 h. Hypoxia and subsequent reoxygenation triggered a disturbance in antioxidant homeostasis, displayed in the modification of GPx expression/activity in the liver: GPx was improved. CONCLUSIONS: These results provide valuable information on the role of Mn-SOD regulation in oxidative stress caused by hypoxia.

Mitochondrial manganese superoxide dismutase knock-down increases oxidative stress and caspase-3 activity in the white shrimp Litopenaeus vannamei exposed to high temperature, hypoxia, and reoxygenation.

Shrimp are increasingly exposed to warmer temperatures and lower oxygen concentrations in their habitat due to climate change. These conditions may lead to oxidative stress and apoptosis. We studied the effects of high temperature, hypoxia, reoxygenation, and the combination of these factors on lipid peroxidation, protein carbonylation, and caspase-3 activity in gills of white shrimp Litopenaeus vannamei. Silencing of mitochondrial manganese superoxide dismutase (mMnSOD) was used to determine the role of this enzyme in response to the abiotic stressors described above, to avoid oxidative damage and apoptosis. In addition, mMnSOD gene expression and mitochondrial SOD activity were evaluated to determine the efficiency of silencing this enzyme. The results showed that there was no effect of the abiotic stress conditions on the thiobarbituric acid reactive substances (TBARS), but protein carbonylation increased in all the oxidative stress treatments and caspase-3 activity decreased in hypoxia at 28 °C. On the other hand, mMnSOD-silenced shrimp experienced higher oxidative stress, since TBARS, carbonylated proteins and caspase-3 activity increased in some silenced treatments. Unexpectedly, mitochondrial SOD activity increased in some of the silenced treatments as well. Altogether, these results suggest that mMnSOD has a key role in shrimp for the prevention of oxidative damage development and induction of apoptosis in response to hypoxia, reoxygenation, high temperature, and their interactions, as conditions derived from climate change.