Human copper-containing superoxide dismutase of high molecular weight

Anti-Inflammatory, Antioxidant and Antibacterial Properties of Tomato Skin and Pomegranate Peel Extracts: A Sustainable Approach for Oral Health Care

Agricultural food waste and by-products could provide high-value compounds that positively affect human and environmental health, thus representing promising ingredients for cosmeceutical products. This study explores the biological activities of tomato skin (HP) and pomegranate peel (PPE) extracts on oral mucosa to evaluate their possible use in mouthwashes. The biological activities of the extracts and the mouthwash (MW) containing them were evaluated in Human Primary Gingival Epithelial cells (HGECs). The antioxidant and anti-inflammatory activities were analyzed in HGECs injured with lipopolysaccharides. After 24 h of treatment with PPE, HP, and MW, significant antioxidant activity and an increased Superoxide Dismutase 1 expression (p < 0.01) were observed. Additionally, the extracts significantly reduced the expression of tumor necrosis factor α (p < 0.05) and Monocyte Chemoattractant Protein 1 (p < 0.001), suggesting an anti-inflammatory role. Lastly, the antibacterial activity was assessed against Streptococcus mutans and Streptococcus sanguinis by the broth microdilution method and agar cup diffusion test for the extracts and the mouthwash, respectively, demonstrating strong effectiveness against both oral streptococcus species. Results demonstrate the potential of HP and PPE in reducing oxidative stress, inflammation, and bacterial proliferation within oral mucosa, highlighting food waste up-cycling as a resource for human health.

Specific analysis of SOD1 enzymatic activity in CSF from ALS patients with and without SOD1 mutations

Mutations in superoxide dismutase-1 (SOD1) are a cause of hereditary amyotrophic lateral sclerosis (ALS) through a gain-of-function mechanism involving unfolded mutant SOD1. Intrathecal gene therapy using the antisense-oligo-nucleotide drug tofersen to reduce SOD1 expression delays disease progression and has recently been approved in the United States and the European Union. However, the discovery of children homozygous for inactivating SOD1 mutations developing the SOD1 Deficiency Syndrome (ISODDES) with injury to the motor system suggests that a too low SOD1 antioxidant activity may be deleterious in humans. Measuring SOD1 activity in cerebrospinal fluid (CSF) in tofersen-treated patients is recommended but difficult due to low concentration and the presence of the isoenzyme SOD3. We here present a sensitive method to assess SOD1 activity by removing SOD3 from CSF samples using highly specific immobilized antibodies and subsequent measurement of the SOD activity. We validated the method on 171 CSF samples from ALS patients with and without mutations and controls and used paired erythrocyte samples for comparison. We found that in ALS patients with wildtype SOD1, the SOD1 activity in CSF was equal to controls, but patients with mutant SOD1 show lower activity in CSF, even for patients with mutants previously reported to have full activity in erythrocytes. Activity variation in CSF was large among patients carrying the same SOD1 mutation and larger than in erythrocytes and in post-mortem nervous tissue. Additionally, we identified a discrepancy between the SOD1 activity and protein level measured with ELISA in both CSF and erythrocytes. Since antibodies used for SOD1 ELISA-quantification are raised against the natively folded wildtype SOD1, the concentration of mutant SOD1s may be underestimated. Analysis of SOD1 enzymatic activity in CSF is therefore a more reliable way to monitor the effect of SOD1-lowering drugs.

Current potential pathogenic mechanisms of copper-zinc superoxide dismutase 1 (SOD1) in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease which damages upper and lower motor neurons (UMN and LMN) innervating the muscles of the trunk, extremities, head, neck and face in cerebrum, brain stem and spinal cord, which results in the progressive weakness, atrophy and fasciculation of muscle innervated by the related UMN and LMN, accompanying with the pathological signs leaded by the cortical spinal lateral tract lesion. The pathogenesis about ALS is not fully understood, and no specific drugs are available to cure and prevent the progression of this disease at present. In this review, we reviewed the structure and associated functions of copper-zinc superoxide dismutase 1 (SOD1), discuss why SOD1 is crucial to the pathogenesis of ALS, and outline the pathogenic mechanisms of SOD1 in ALS that have been identified at recent years, including glutamate-related excitotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, oxidative stress, axonal transport disruption, prion-like propagation, and the non-cytologic toxicity of glial cells. This review will help us to deeply understand the current progression in this field of SOD1 pathogenic mechanisms in ALS.

Role of copper and SOD3-mediated extracellular redox regulation in tumor progression

Copper (Cu), an essential micronutrient, participates in several physiological processes, including cell proliferation and development. Notably, the disturbance of Cu homeostasis promotes tumor progression through the generation of oxidative stress. Chronic or excessive accumulation of reactive oxygen species (ROS) causes lipid peroxidation, protein denaturation, and enzyme inactivation, which leads to a breakdown of intracellular homeostasis and exacerbates tumor progression. The disruption of the ROS scavenging mechanism also reduces resistance to oxidative stress, leading to further deterioration in a disease state, and maintenance of redox homeostasis is thought to inhibit the onset and progression of various diseases. Superoxide dismutase 3 (SOD3), a Cu-containing secretory antioxidative enzyme, plays a key role in extracellular redox regulation, and the significant reduction in SOD3 facilitates tumor progression. Furthermore, the significant induction of SOD3 participates in tumor metastasis. This review focuses on the role of Cu homeostasis and antioxidative enzymes, including SOD3, in tumor progression, to help clarify the role of redox regulation.

Advances in metal-organic framework-based nanozymes in ROS scavenging medicine

Reactive oxygen species (ROS) play important roles in regulating various physiological functions in the human body, however, excessive ROS can cause serious damage to the human body, considering the various limitations of natural enzymes as scavengers of ROS in the body, the development of better materials for the scavenging of ROS is of great significance to the biomedical field, and nanozymes, as a kind of nanomaterials which can show the activity of natural enzymes. Have a good potential for the development in the area of ROS scavenging. Metal-organic frameworks (MOFs), which are porous crystalline materials with a periodic network structure composed of metal nodes and organic ligands, have been developed with a variety of active nanozymes including catalase-like, superoxide dismutase-like, and glutathione peroxidase-like enzymes due to the adjustability of active sites, structural diversity, excellent biocompatibility, and they have shown a wide range of applications and prospects. In the present review, we first introduce three representative natural enzymes for ROS scavenging in the human body, methods for the detection of relevant enzyme-like activities and mechanisms of enzyme-like clearance are discussed, meanwhile, we systematically summarize the progress of the research on MOF-based nanozymes, including the design strategy, mechanism of action, and medical application, etc. Finally, the current challenges of MOF-based nanozymes are summarized, and the future development direction is anticipated. We hope that this review can contribute to the research of MOF-based nanozymes in the medical field related to the scavenging of ROS.

Orthologs of NOX5 and EC-SOD/SOD3: dNox and dSod3 Impact Egg Hardening Process and Egg Laying in Reproductive Function of Drosophila melanogaster

The occurrence of ovarian dysfunction is often due to the imbalance between the formation of reactive oxygen species (ROS) and the ineffectiveness of the antioxidative defense mechanisms. Primary sources of ROS are respiratory electron transfer and the activity of NADPH oxidases (NOX) while superoxide dismutases (SOD) are the main key regulators that control the levels of ROS and reactive nitrogen species intra- and extracellularly. Because of their central role SODs are the subject of research on human ovarian dysfunction but sample acquisition is low. The high degree of cellular and molecular similarity between Drosophila melanogaster ovaries and human ovaries provides this model organism with the best conditions for analyzing the role of ROS during ovarian function. In this study we clarify the localization of the ROS-producing enzyme dNox within the ovaries of Drosophila melanogaster and by a tissue-specific knockdown we show that dNox-derived ROS are involved in the chorion hardening process. Furthermore, we analyze the dSod3 localization and show that reduced activity of dSod3 impacts egg-laying behavior but not the chorion hardening process.

Enzymes for dermatological use

Skin is the ultimate barrier between body and environment and prevents water loss and penetration of pathogens and toxins. Internal and external stressors, such as ultraviolet radiation (UVR), can damage skin integrity and lead to disorders. Therefore, skin health and skin ageing are important concerns and increased research from cosmetic and pharmaceutical sectors aims to improve skin conditions and provide new anti-ageing treatments. Biomolecules, compared to low molecular weight drugs and cosmetic ingredients, can offer high levels of specificity. Topically applied enzymes have been investigated to treat the adverse effects of sunlight, pollution and other external agents. Enzymes, with a diverse range of targets, present potential for dermatological use such as antioxidant enzymes, proteases and repairing enzymes. In this review, we discuss enzymes for dermatological applications and the challenges associated in this growing field.

Cuproptosis: A novel therapeutic target for overcoming cancer drug resistance

Cuproptosis is a newly identified form of cell death driven by copper. Recently, the role of copper and copper triggered cell death in the pathogenesis of cancers have attracted attentions. Cuproptosis has garnered enormous interest in cancer research communities because of its great potential for cancer therapy. Copper-based treatment exerts an inhibiting role in tumor growth and may open the door for the treatment of chemotherapy-insensitive tumors. In this review, we provide a critical analysis on copper homeostasis and the role of copper dysregulation in the development and progression of cancers. Then the core molecular mechanisms of cuproptosis and its role in cancer is discussed, followed by summarizing the current understanding of copper-based agents (copper chelators, copper ionophores, and copper complexes-based dynamic therapy) for cancer treatment. Additionally, we summarize the emerging data on copper complexes-based agents and copper ionophores to subdue tumor chemotherapy resistance in different types of cancers. We also review the small-molecule compounds and nanoparticles (NPs) that may kill cancer cells by inducing cuproptosis, which will shed new light on the development of anticancer drugs through inducing cuproptosis in the future. Finally, the important concepts and pressing questions of cuproptosis in future research that should be focused on were discussed. This review article suggests that targeting cuproptosis could be a novel antitumor therapy and treatment strategy to overcome cancer drug resistance.

Extracellular SOD modulates canonical TNFα signaling and α5β1 integrin transactivation in vascular smooth muscle cells

TNFα activates NADPH oxidase 1 (Nox1) in vascular smooth muscle cells (VSMCs). The extracellular superoxide anion (O2•-) produced is essential for the pro-inflammatory effects of the cytokine but the specific contributions of O2•- to signal transduction remain obscure. Extracellular superoxide dismutase (ecSOD, SOD3 gene) is a secreted protein that binds to cell surface heparin sulfate proteoglycans or to Fibulin-5 (Fib-5, FBLN5 gene), an extracellular matrix protein that also associates with elastin and integrins. ecSOD converts O2•- to hydrogen peroxide (H2O2) which prevents NO• inactivation, limits generation of hydroxyl radical (OH•), and creates high local concentrations of H2O2. We hypothesized that ecSOD modifies TNFα signaling in VSMCs. Knockdown of ecSOD (siSOD3) suppressed downstream TNFα signals including MAPK (JNK and ERK phosphorylation) and NF-κB activation (luciferase reporter and IκB phosphorylation), interleukin-6 (IL-6) secretion, iNOS and VCAM expression, and proliferation (Sulforhodamine B assay, PCNA western blot). These effects were associated with significant reductions in the expression of both Type1 and 2 TNFα receptors. Reduced Fib-5 expression (siFBLN5) similarly impaired NF-κB activation by TNFα, but potentiated FAK phosphorylation at Y925. siSOD3 also increased both resting and TNFα-induced phosphorylation of FAK and of glycogen synthase kinase-3β (GSK3β), a downstream target of integrin linked kinase (ILK). These effects were dependent upon α5β1 integrins and siSOD3 increased resting sulfenylation (oxidation) of both integrin subunits, while preventing TNFα-induced increases in sulfenylation. To determine how ecSOD modified TNFα-induced inflammation in intact blood vessels, mesenteric arteries from VSMC-specific ecSOD knockout (KO) mice were exposed to TNFα (10 ng/ml) in culture for 48 h. Relaxation to acetylcholine and sodium nitroprusside was impaired in WT but not ecSOD KO vessels. Thus, ecSOD association with Fib-5 supports pro-inflammatory TNFα signaling while tonically inhibiting α5β1 integrin activation.

A tetranuclear Mn-diamond core complex as a functional mimic of both catechol oxidase and phenoxazinone synthase enzymes

Through dioxygen activation, a tetranuclear Mn(II,III,III,II) diamond core, [Mn4(HPTP*)2(μ-O)2(H2O)4](ClO4)4 (1) complex, has been synthesised using a suitably designed septadentate ligand framework (HPTP*H = 1,3-bis(bis((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)amino)propan-2-ol). The newly prepared complex 1 was characterised using multiple spectroscopic techniques and X-ray crystallography. 1 exhibits excellent catalytic oxidation reactivity for the model substrates, namely, 3,5-di-tert-butylcatechol (3,5-DTBC) and 2-aminophenol, efficiently mimicking the enzymes catechol oxidase and phenoxazinone synthase, respectively. Remarkably, we employed aerial oxygen to catalyze the oxidation of these model substrates, 3,5-DTBC and 2-aminophenol, with turnover numbers of 835 and 14, respectively. A tetranuclear Mn-diamond core complex that mimics both catechol oxidase and phenoxazinone synthase could pave the way for further research into its potential as a multi-enzymatic functional mimic.

Copper homeostasis and the ubiquitin proteasome system

Copper is involved in many physiological pathways and important biological processes as a cofactor of several copper-dependent enzymes. Given the requirement for copper and its potential toxicity, intracellular copper levels are tightly controlled. Disturbances of human copper homeostasis are characterized by disorders of copper overload (Wilson's disease) or copper deficiency (Menkes disease). The maintenance of cellular copper levels involves numerous copper transporters and copper chaperones. Recently, accumulating evidence has revealed that components of the ubiquitin proteasome system (UPS) participate in the posttranslational regulation of these proteins, suggesting that they might play a role in maintaining copper homeostasis. Cellular copper levels could also affect the activity of the UPS, indicating that copper homeostasis and the UPS are interdependent. Copper homeostasis and the UPS are essential to the integrity of normal brain function and while separate links between neurodegenerative diseases and UPS inhibition/copper dyshomeostasis have been extensively reported, there is growing evidence that these two networks might contribute synergistically to the occurrence of neurodegenerative diseases. Here, we review the role of copper and the UPS in the development of Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, and discuss the genetic interactions between copper transporters/chaperones and components of the UPS.

Core Fucosylation Is Required for the Secretion of and the Enzymatic Activity of SOD3 in Nonsmall-Cell Lung Cancer Cells

Aims: The anticancer function of superoxide dismutases (SODs) is still controversial. SOD3 is an extracellular superoxide dismutase and contains a single N-glycan chain. The role played by the N-glycosylation of SOD3, as it relates to lung cancer, is poorly understood. For this, we performed the structural and functional analyses of the N-glycan of SOD3 in lung cancer. Results: We report herein that the fucose structure of the N-glycan in SOD3 was increased in the sera of patients with lung cancer. In cell lines of non-small lung cancer cell (NSCLC), we also found a high level of the core fucose structure in the N-glycan of SOD3, as determined by lectin blotting and mass spectrometry analysis. To address the roles of the core fucose structure of SOD3, we generated FUT8 (α1,6-fucosyltransferase) gene knockout A549 cells. Using these cells, we found that the core fucose structure of SOD3 was required for its secretion and enzymatic activity, which contributes to the suppression of cell growth of NSCLC cells. Innovation: The core fucosylation is required for the secretion and enzymatic activity of SOD3, which contributes to anti-tumor functions such as the suppression of cell growth of NSCLC. Conclusion: The N-glycans, especially those with core fucose structures, regulate the anti-tumor functions of SOD3 against NSCLC.

The motor system is exceptionally vulnerable to absence of the ubiquitously expressed superoxide dismutase-1

Superoxide dismutase-1 is a ubiquitously expressed antioxidant enzyme. Mutations in SOD1 can cause amyotrophic lateral sclerosis, probably via a toxic gain-of-function involving protein aggregation and prion-like mechanisms. Recently, homozygosity for loss-of-function mutations in SOD1 has been reported in patients presenting with infantile-onset motor neuron disease. We explored the bodily effects of superoxide dismutase-1 enzymatic deficiency in eight children homozygous for the p.C112Wfs*11 truncating mutation. In addition to physical and imaging examinations, we collected blood, urine and skin fibroblast samples. We used a comprehensive panel of clinically established analyses to assess organ function and analysed oxidative stress markers, antioxidant compounds, and the characteristics of the mutant Superoxide dismutase-1. From around 8 months of age, all patients exhibited progressive signs of both upper and lower motor neuron dysfunction, cerebellar, brain stem, and frontal lobe atrophy and elevated plasma neurofilament concentration indicating ongoing axonal damage. The disease progression seemed to slow down over the following years. The p.C112Wfs*11 gene product is unstable, rapidly degraded and no aggregates were found in fibroblast. Most laboratory tests indicated normal organ integrity and only a few modest deviations were found. The patients displayed anaemia with shortened survival of erythrocytes containing decreased levels of reduced glutathione. A variety of other antioxidants and oxidant damage markers were within normal range. In conclusion, non-neuronal organs in humans show a remarkable tolerance to absence of Superoxide dismutase-1 enzymatic activity. The study highlights the enigmatic specific vulnerability of the motor system to both gain-of-function mutations in SOD1 and loss of the enzyme as in the here depicted infantile superoxide dismutase-1 deficiency syndrome.

Characterization of ancestral Fe/Mn superoxide dismutases indicates their cambialistic origin

Superoxide dismutases (SODs) are critical metalloenzymes mitigating the damages of the modern oxygenated world. However, the emergence of one family of SODs, the Fe/Mn SOD, has been recurrently proposed to predate the great oxygenation event (GOE). This ancient family lacks metal binding selectivity, but displays strong catalytic selectivity. Therefore, some homologues would only be active when bound to Fe or Mn, although others, dubbed cambialistic, would function when loaded with either ion. This posed the longstanding question about the identity of the cognate metal ion of the first SODs to emerge. In this work, we utilize ancestral sequence reconstruction techniques to infer the earliest SODs. We show that the "ancestors" are active in vivo and in vitro. Further, we test their metal specificity and demonstrate that they are cambialistic in nature. Our findings shed light on how the predicted Last Common Universal Ancestor was capable of dealing with decomposition of the superoxide anion, and the early relationship between life, oxygen, and metal ion availability.

Pooled resequencing of larvae and adults reveals genomic variations associated with Ostreid herpesvirus 1 resistance in the Pacific oyster Crassostrea gigas

The Ostreid herpesvirus 1 (OsHV-1) is a lethal pathogen of the Pacific oyster (Crassostrea gigas), an important aquaculture species. To understand the genetic architecture of the defense against the pathogen, we studied genomic variations associated with herpesvirus-caused mortalities by pooled whole-genome resequencing of before and after-mortality larval samples as well as dead and surviving adults from a viral challenge. Analysis of the resequencing data identified 5,271 SNPs and 1,883 genomic regions covering 3,111 genes in larvae, and 18,692 SNPs and 28,314 regions covering 4,863 genes in adults that were significantly associated with herpesvirus-caused mortalities. Only 1,653 of the implicated genes were shared by larvae and adults, suggesting that the antiviral response or resistance in larvae and adults involves different sets of genes or differentiated members of expanded gene families. Combined analyses with previous transcriptomic data from challenge experiments revealed that transcription of many mortality-associated genes was also significantly upregulated by herpesvirus infection confirming their importance in antiviral response. Key immune response genes especially those encoding antiviral receptors such as TLRs and RLRs displayed strong association between variation in regulatory region and herpesvirus-caused mortality, suggesting they may confer resistance through transcriptional modulation. These results point to previously undescribed genetic mechanisms for disease resistance at different developmental stages and provide candidate polymorphisms and genes that are valuable for understanding antiviral immune responses and breeding for herpesvirus resistance.

Antioxidant Systems, lncRNAs, and Tunneling Nanotubes in Cell Death Rescue from Cigarette Smoke Exposure

Cigarette smoke is a rich source of carcinogens and reactive oxygen species (ROS) that can damage macromolecules including DNA. Repair systems can restore DNA integrity. Depending on the duration or intensity of stress signals, cells may utilize various survival and adaptive mechanisms. ROS levels are kept in check through redundant detoxification processes controlled largely by antioxidant systems. This review covers and expands on the mechanisms available to cigarette smoke-exposed cancer cells for restoring the redox balance. These include multiple layers of transcriptional control, each of which is posited to be activated upon reaching a particular stress threshold, among them the NRF2 pathway, the AP-1 and NF-kB pathways, and, finally, TP53, which triggers apoptosis if extreme toxicity is reached. The review also discusses long noncoding RNAs, which have been implicated recently in regulating oxidative stress-with roles in ROS detoxification, the inflammatory response, oxidative stress-induced apoptosis, and mitochondrial oxidative phosphorylation. Lastly, the emerging roles of tunneling nanotubes in providing additional mechanisms for metabolic rescue and the regulation of redox imbalance are considered, further highlighting the expanded redox reset arsenal available to cells.

Polyphenols in Ruminant Nutrition and Their Effects on Reproduction

The feeding of domestic animals with diets in which polyphenols are present is increasingly attracting the attention of nutritionists and scientists. This review summarizes the knowledge regarding polyphenols' possible positive and negative effects and their bioavailability. The bioavailability of substances is a prerequisite for any postabsorption effect in vivo. Positive and negative properties have been confirmed in previous studies on the diets of domestic animals rich in polyphenols, such as secondary metabolites of plants. Free radicals are formed in every organism, leading to oxidative stress. Free radicals are highly reactive molecules and can react in cells with macromolecules and can cause damage, including in reproductive cells. Some polyphenols at specific concentrations have antioxidant properties that positively affect animal reproduction by improving the quality of male and female gametes. The intake of phytoestrogens that mimic estrogen function can induce various pathological conditions in the female reproductive tract, including ovarian, fallopian, and uterine dysfunction. The metabolism of genistein and daidzein yields the metabolites equol and p-phenyl-phenol, leading to a decline in cow fertilization. The findings so far confirm that numerous questions still need to be answered. This review points out the importance of using polyphenols that have both benificial and some unfavorable properties in specific diets.

Protective Effects of N-Acetylcysteine on Lipopolysaccharide-Induced Respiratory Inflammation and Oxidative Stress

As the leading cause of bovine respiratory disease (BRD), bacterial pneumonia can result in tremendous losses in the herd farming industry worldwide. N-acetylcysteine (NAC), an acetylated precursor of the amino acid L-cysteine, has been reported to have anti-inflammatory and antioxidant properties. To explore the protective effect and underlying mechanisms of NAC in ALI, we investigated its role in lipopolysaccharide (LPS)-induced bovine embryo tracheal cells (EBTr) and mouse lung injury models. We found that NAC pretreatment attenuated LPS-induced inflammation in EBTr and mouse models. Moreover, LPS suppressed the expression of oxidative-related factors in EBTr and promoted gene expression and the secretion of inflammatory cytokines. Conversely, the pretreatment of NAC alleviated the secretion of inflammatory cytokines and decreased their mRNA levels, maintaining stable levels of antioxidative gene expression. In vivo, NAC helped LPS-induced inflammatory responses and lung injury in ALI mice. The relative protein concentration, total cells, and percentage of neutrophils in BALF; the level of secretion of IL-6, IL-8, TNF-α, and IL-1β; MPO activity; lung injury score; and the expression level of inflammatory-related genes were decreased significantly in the NAC group compared with the LPS group. NAC also ameliorated LPS-induced mRNA level changes in antioxidative genes. In conclusion, our findings suggest that NAC affects the inflammatory and oxidative response, alleviating LPS-induced EBTr inflammation and mouse lung injury, which offers a natural therapeutic strategy for BRD.

Combined action of FOXO1 and superoxide dismutase 3 promotes MDA-MB-231 cell migration

Superoxide dismutase 3 (SOD3), one of SOD isozymes, maintains extracellular redox homeostasis through the dismutation reaction of superoxide. Loss of SOD3 in tumor cells induces oxidative stress and exacerbates tumor progression; however, interestingly, overexpression of SOD3 also promotes cell proliferation through the production of hydrogen peroxide. In this study, we investigated the functional role of SOD3 in human breast cancer MDA-MB-231 cell migration and the molecular mechanisms involved in high expression of SOD3 in MDA-MB-231 cells and human monocytic THP-1 cells. The level of histone H3 trimethylation at lysine 27 (H3K27me3), a marker of gene silencing, was decreased in 12-O-tetra-decanoylphorbol-13-acetate (TPA)-treated THP-1 cells. Also, that reduction was observed within the SOD3 promoter region. We then investigated the involvement of H3K27 demethylase JMJD3 in SOD3 induction. The induction of SOD3 and the reduction of H3K27me3 were inhibited in the presence of JMJD3 inhibitor, GSK-J4. Additionally, it was first determined that the knockdown of the transcription factor forkhead box O1 (FOXO1) significantly suppressed TPA-elicited SOD3 induction. FOXO1-mediated SOD3 downregulation was also observed in MDA-MB-231 cells, and knockdown of FOXO1 and SOD3 suppressed cell migration. Our results provide a novel insight into epigenetic regulation of SOD3 expression in tumor-associated cells, and high expression of FOXO1 and SOD3 would participate in the migration of MDA-MB-231 cells.

The Interconnected Mechanisms of Oxidative Stress and Neuroinflammation in Epilepsy

One of the most important characteristics of the brain compared to other organs is its elevated metabolic demand. Consequently, neurons consume high quantities of oxygen, generating significant amounts of reactive oxygen species (ROS) as a by-product. These potentially toxic molecules cause oxidative stress (OS) and are associated with many disorders of the nervous system, where pathological processes such as aberrant protein oxidation can ultimately lead to cellular dysfunction and death. Epilepsy, characterized by a long-term predisposition to epileptic seizures, is one of the most common of the neurological disorders associated with OS. Evidence shows that increased neuronal excitability—the hallmark of epilepsy—is accompanied by neuroinflammation and an excessive production of ROS; together, these factors are likely key features of seizure initiation and propagation. This review discusses the role of OS in epilepsy, its connection to neuroinflammation and the impact on synaptic function. Considering that the pharmacological treatment options for epilepsy are limited by the heterogeneity of these disorders, we also introduce the latest advances in anti-epileptic drugs (AEDs) and how they interact with OS. We conclude that OS is intertwined with numerous physiological and molecular mechanisms in epilepsy, although a causal relationship is yet to be established.

Copper in the tumor microenvironment and tumor metastasis

Copper (Cu), an essential micronutrient, plays an essential role in several physiological processes, including cell proliferation and angiogenesis; however, its dysregulation induces oxidative stress and inflammatory responses. Significant Cu accumulation is observed in several tumor tissues. The bioavailability of intracellular Cu is tightly controlled by Cu transporters, including Cu transporter 1 (CTR1) and Cu-transporting P-type ATPase α and β (ATP7A and ATP7B), and Cu chaperones, including Cu chaperone for superoxide dismutase 1 (CCS) and antioxidant-1 (Atox-1). In several tumor tissues, these abnormalities that induce intra­cellular Cu accumulation are involved in tumor progression. In addition, functional disturbance in Cu-containing secretory enzymes, such as superoxide dismutase 3 (SOD3), and lysyl oxidase enzymes (LOX and LOXL1–4) with abnormal Cu dynamics plays a key role in tumor metastasis. For example, the loss of SOD3 in tumor tissues induces oxidative stress, which promotes neovascularization and epithelial-to-mesenchymal transition (EMT). LOX promotes collagen crosslinking, which functions in the metastatic niche formation. Accordingly, restricted Cu regulation may be a novel strategy for the inhibition of tumor metastasis. However, it is unclear how these Cu disturbances occur in tumor tissues and the exact molecular mechanisms underlying Cu secretory enzymes. In this review article, I discuss the role of Cu transporters, Cu chaperones, and Cu-containing secretory enzymes in tumor progression to better understand the role of Cu homeostasis in tumor tissues.

Interchangeable utilization of metals: New perspectives on the impacts of metal ions employed in ancient and extant biomolecules

Metal ions provide considerable functionality across biological systems, and their utilization within biomolecules has adapted through changes in the chemical environment to maintain the activity they facilitate. While ancient earth's atmosphere was rich in iron and manganese and low in oxygen, periods of atmospheric oxygenation significantly altered the availability of certain metal ions, resulting in ion replacement within biomolecules. This adaptation mechanism has given rise to the phenomenon of metal cofactor interchangeability, whereby contemporary proteins and nucleic acids interact with multiple metal ions interchangeably, with different coordinated metals influencing biological activity, stability, and toxic potential. The ability of extant organisms to adapt to fluctuating metal availability remains relevant in a number of crucial biomolecules, including the superoxide dismutases of the antioxidant defense systems and ribonucleotide reductases. These well-studied and ancient enzymes illustrate the potential for metal interchangeability and adaptive utilization. More recently, the ribosome has also been demonstrated to exhibit interchangeable interactions with metal ions with impacts on function, stability, and stress adaptation. Using these and other examples, here we review the biological significance of interchangeable metal ions from a new angle that combines both biochemical and evolutionary viewpoints. The geochemical pressures and chemical properties that underlie biological metal utilization are discussed in the context of their impact on modern disease states and treatments.

Infantile SOD1 deficiency syndrome caused by a homozygous SOD1 variant with absence of enzyme activity

Pathogenic variants in SOD1, encoding superoxide dismutase 1, are responsible for about 20% of all familial amyotrophic lateral sclerosis cases, through a gain-of-function mechanism. Recently, two reports showed that a specific homozygous SOD1 loss-of-function variant is associated with an infantile progressive motor-neurological syndrome. Exome sequencing followed by molecular studies, including cDNA analysis, SOD1 protein levels and enzymatic activity, and plasma neurofilament light chain levels, were undertaken in an infant with severe global developmental delay, axial hypotonia and limb spasticity. We identified a homozygous 3-bp in-frame deletion in SOD1. cDNA analysis predicted the loss of a single valine residue from a tandem pair (p.Val119/Val120) in the wild-type protein, yet expression levels and splicing were preserved. Analysis of SOD1 activity and protein levels in erythrocyte lysates showed essentially no enzymatic activity and undetectable SOD1 protein in the child, whereas the parents had ∼50% protein expression and activity relative to controls. Neurofilament light chain levels in plasma were elevated, implying ongoing axonal injury and neurodegeneration. Thus, we provide confirmatory evidence of a second biallelic variant in an infant with a severe neurological syndrome and suggest that the in-frame deletion causes instability and subsequent degeneration of SOD1. We highlight the importance of the valine residues at positions V119-120, and suggest possible implications for future therapeutics research.

ROS as Regulators of Cellular Processes in Melanoma

In this review, we examine the multiple roles of ROS in the pathogenesis of melanoma, focusing on signal transduction and regulation of gene expression. In recent years, different studies have analyzed the dual role of ROS in regulating the redox system, with both negative and positive consequences on human health, depending on cell concentration of these agents. High ROS levels can result from an altered balance between oxidant generation and intracellular antioxidant activity and can produce harmful effects. In contrast, low amounts of ROS are considered beneficial, since they trigger signaling pathways involved in physiological activities and programmed cell death, with protective effects against melanoma. Here, we examine these beneficial roles, which could have interesting implications in melanoma treatment.

Cooperation between CYB5R3 and NOX4 via coenzyme Q mitigates endothelial inflammation

NADPH oxidase 4 (NOX4) regulates endothelial inflammation by producing hydrogen peroxide (H₂O₂) and to a lesser extent O₂^•-. The ratio of NOX4-derived H₂O₂ and O₂^•- can be altered by coenzyme Q (CoQ) mimics. Therefore, we hypothesize that cytochrome b5 reductase 3 (CYB5R3), a CoQ reductase abundant in vascular endothelial cells, regulates inflammatory activation. To examine endothelial CYB5R3 in vivo, we created tamoxifen-inducible endothelium-specific Cyb5r3 knockout mice (R3 KO). Radiotelemetry measurements of systolic blood pressure showed systemic hypotension in lipopolysaccharides (LPS) challenged mice, which was exacerbated in R3 KO mice. Meanwhile, LPS treatment caused greater endothelial dysfunction in R3 KO mice, evaluated by acetylcholine-induced vasodilation in the isolated aorta, accompanied by elevated mRNA expression of vascular adhesion molecule 1 (Vcam-1). Similarly, in cultured human aortic endothelial cells (HAEC), LPS and tumor necrosis factor α (TNF-α) induced VCAM-1 protein expression was enhanced by Cyb5r3 siRNA, which was ablated by silencing the Nox4 gene simultaneously. Moreover, super-resolution confocal microscopy indicated mitochondrial co-localization of CYB5R3 and NOX4 in HAECs. APEX2-based electron microscopy and proximity biotinylation also demonstrated CYB5R3's localization on the mitochondrial outer membrane and its interaction with NOX4, which was further confirmed by the proximity ligation assay. Notably, Cyb5r3 knockdown HAECs showed less total H₂O₂ but more mitochondrial O₂^•-. Using inactive or non-membrane bound active CYB5R3, we found that CYB5R3 activity and membrane translocation are needed for optimal generation of H₂O₂ by NOX4. Lastly, cells lacking the CoQ synthesizing enzyme COQ6 showed decreased NOX4-derived H₂O₂, indicating a requirement for endogenous CoQ in NOX4 activity. In conclusion, CYB5R3 mitigates endothelial inflammatory activation by assisting in NOX4-dependent H₂O₂ generation via CoQ.

Neonatal Extracellular Superoxide Dismutase Knockout Mice Increase Total Superoxide Dismutase Activity and VEGF Expression after Chronic Hyperoxia

Bronchopulmonary dysplasia (BPD) is a common lung disease affecting premature infants that develops after exposure to supplemental oxygen and reactive oxygen intermediates. Extracellular superoxide dismutase (SOD3) is an enzyme that processes superoxide radicals and has been shown to facilitate vascular endothelial growth factor (VEGF) and nitric oxide (NO) signaling in vascular endothelium. We utilized a mouse model of neonatal hyperoxic lung injury and SOD3 knockout (KO) mice to evaluate its function during chronic hyperoxia exposure. Wild-type age-matched neonatal C57Bl/6 (WT) and SOD3^−/− (KO) mice were placed in normoxia (21% FiO₂, RA) or chronic hyperoxia (75% FiO₂, O₂) within 24 h of birth for 14 days continuously and then euthanized. Lungs were harvested for histologic evaluation, as well as comparison of antioxidant enzyme expression, SOD activity, VEGF expression, and portions of the NO signaling pathway. Surprisingly, KO-O₂ mice survived without additional alveolar simplification, microvascular remodeling, or nuclear oxidation when compared to WT-O₂ mice. KO-O₂ mice had increased total SOD activity and increased VEGF expression when compared to WT-O₂ mice. No genotype differences were noted in intracellular antioxidant enzyme expression or the NO signaling pathway. These results demonstrate that SOD3 KO mice can survive prolonged hyperoxia without exacerbation of alveolar or vascular phenotype.

Expanding the link between circadian rhythms and redox metabolism of epigenetic control

Circadian rhythms play a central role in physiological and metabolic processes. This is mostly achieved through rhythmic regulation of myriad genes via dynamic epigenome changes. Accumulating evidence indicates that oxidative stress and redox balance are under circadian control and feedback on the clock system. Circadian perturbations induce oxidative stress accumulation and disturb redox balance. Along with these changes, epigenomic landscape changes are a remarkable hallmark of clock disruption. This review aims to summarize evidence supporting the link between the circadian clock and redox metabolism, focusing on possible connections through epigenetic mechanisms.

SOD3 deficiency induces liver fibrosis by promoting hepatic stellate cell activation and epithelial-mesenchymal transition

Hepatic stellate cell (HSC) activation plays an important role in the pathogenesis of liver fibrosis, and epithelial-mesenchymal transition (EMT) is suggested to potentially promote HSC activation. Superoxide dismutase 3 (SOD3) is an extracellular antioxidant defense against oxidative damage. Here, we found downregulation of SOD3 in a mouse model of liver fibrosis induced by carbon tetrachloride (CCl4 ). SOD3 deficiency induced spontaneous liver injury and fibrosis with increased collagen deposition, and further aggravated CCl4 -induced liver injury in mice. Depletion of SOD3 enhanced HSC activation marked by increased α-smooth muscle actin and subsequent collagen synthesis primarily collagen type I in vivo, and promoted transforming growth factor-β1 (TGF-β1)-induced HSC activation in vitro. SOD3 deficiency accelerated EMT process in the liver and TGF-β1-induced EMT of AML12 hepatocytes, as evidenced by loss of E-cadherin and gain of N-cadherin and vimentin. Notably, SOD3 expression and its pro-fibrogenic effect were positively associated with sirtuin 1 (SIRT1) expression. SOD3 deficiency inhibited adenosine monophosphate-activated protein kinase (AMPK) signaling to downregulate SIRT1 expression and thus involving in liver fibrosis. Enforced expression of SIRT1 inhibited SOD3 deficiency-induced HSC activation and EMT, whereas depletion of SIRT1 counteracted the inhibitory effect of SOD3 in vitro. These findings demonstrate that SOD3 deficiency contributes to liver fibrogenesis by promoting HSC activation and EMT process, and suggest a possibility that SOD3 may function through modulating SIRT1 via the AMPK pathway in liver fibrosis.

Bacterial evolutionary precursors of eukaryotic copper-zinc superoxide dismutases

Internalization of a bacteria by an archaeal cell expedited eukaryotic evolution. An important feature of the species that diversified into the great variety of eukaryotic life visible today was the ability to combat oxidative stress with a copper–zinc superoxide dismutase (CuZnSOD) enzyme activated by a specific, high-affinity copper chaperone. Adoption of a single protein interface that facilitates homodimerization and heterodimerization was essential; however, its evolution has been difficult to rationalize given the structural differences between bacterial and eukaryotic enzymes. In contrast, no consistent strategy for the maturation of periplasmic bacterial CuZnSODs has emerged. Here, 34 CuZnSODs are described that closely resemble the eukaryotic form but originate predominantly from aquatic bacteria. Crystal structures of a Bacteroidetes bacterium CuZnSOD portray both prokaryotic and eukaryotic characteristics and propose a mechanism for self-catalyzed disulfide maturation. Unification of a bacterial but eukaryotic-like CuZnSOD along with a ferredoxin-fold MXCXXC copper-binding domain within a single polypeptide created the advanced copper delivery system for CuZnSODs exemplified by the human copper chaperone for superoxide dismutase-1. The development of this system facilitated evolution of large and compartmentalized cells following endosymbiotic eukaryogenesis.

Novel and Converging Ways of NOX2 and SOD3 in Trafficking and Redox Signaling in Macrophages

Macrophages and related tissue macrophage populations use the classical NADPH oxidase (NOX2) for the regulated production of superoxide and derived oxidants for pathogen combat and redox signaling. With an emphasis on macrophages, we discuss how sorting into secretory storage vesicles, agonist-responsive membrane trafficking, and segregation into sphingolipid and cholesterol-enriched microdomains (lipid rafts) determine the subcellular distribution and spatial organization of NOX2 and superoxide dismutase-3 (SOD3). We discuss how inflammatory activation of macrophages, in part through small GTPase Rab27A/B regulation of the secretory compartments, mediates the coalescence of these two proteins on the cell surface to deliver a focalized hydrogen peroxide output. In interplay with membrane-embedded oxidant transporters and redox sensitive target proteins, this arrangement allows for the autocrine and paracrine signaling, which govern macrophage activation states and transcriptional programs. By discussing examples of autocrine and paracrine redox signaling, we highlight why formation of spatiotemporal microenvironments where produced superoxide is rapidly converted to hydrogen peroxide and conveyed immediately to reach redox targets in proximal vicinity is required for efficient redox signaling. Finally, we discuss the recent discovery of macrophage-derived exosomes as vehicles of NOX2 holoenzyme export to other cells.

Inflammation accelerates copper-mediated cytotoxicity through induction of six-transmembrane epithelial antigens of prostate 4 expression

Copper is an essential trace metal, but imbalance in copper homeostasis can induce oxidative damage. Inflammation is a fundamental element of various pulmonary diseases. Although a positive relationship between copper and chronic pulmonary diseases has been reported, the underlying reasons are still not clear. The copper level in the sputum of patients with various pulmonary diseases was measured. An inflammatory model was established to evaluate the impact of inflammation on copper uptake in the lung. We found that the level of sputum copper was increased in patients with various pulmonary diseases, especially chronic obstructive pulmonary disease and asthma. Then, we confirmed that mice with pulmonary inflammation were susceptible to copper-mediated oxidative damage because of copper overload in lung tissue. Further investigation demonstrated that interleukin (IL)-17 and tumor necrosis factor (TNF)-α exerted synergistic effects in airway epithelial cells by upregulating the expression of six-transmembrane epithelial antigens of prostate 4 (STEAP4), a metalloreductase that reduces extracellular copper ions from the cupric state to the cuprous state and facilitates copper uptake. Inhibition of STEAP4 decreased the copper uptake of cells and inhibited copper-mediated oxidative damage. Moreover, we demonstrated that the upregulation of STEAP4 by IL-17 and TNF-α was largely dependent on TNF receptor-associated factor 4 (TRAF4). Traf4^-/- mice were resistant to copper-mediated oxidative damage. Our data suggest a novel IL-17/TNF-α-TRAF4-STEAP4 axis that regulates copper homeostasis.

Molecular cloning, expression, and characterization of BmSOD3 in silkworm (Bombyx mori)

Superoxide dismutases (SODs) play an essential role in eliminating excess reactive oxygen species and maintaining the redox balance of the immune system. To study the function of BmSOD3 in silkworm, 543-bp full-length complementary DNA-encoding BmSOD3 was cloned from silkworm. The BmSOD3 amino acids were compared to their homologs, and several highly conserved regions were analyzed. We also carried out phylogenetic analyses of the SOD gene. Our results showed that the BmSOD3 gene belonged with the ecCu/Zn SOD gene. The BmSOD3 gene was transformed into the pET28a vector for functional expression in Escherichia coli. The sodium salt-polyacrylamide gel electrophoresis results showed that the molecular weight of recombinant BmSOD3 was about 22 kDa. The recombinant protein BmSOD3 was purified to detect its properties. After purification analyses, the enzyme activity showed Cu/Zn SOD activity, and the specific activity of the purified enzyme was 0.51 U/mg. The BmSOD3 transcripts showed tissue-specific expression in the midgut and malpighian tubule. The immune microarray data for BmSOD3 showed an expression signal that had a strong response to the induction of four pathogens (Bacillus bombyseptieus, Beauveria bassiana, E. coli, and nuclear polyhedrosis virus), particularly after infection for 24 h, which indicates that the BmSOD3 gene plays a key role in response to bacterial, fungal, and viral invasion. The fusion protein also showed antibacterial activity against E. coli in vitro. Thus, the fusion protein BmSOD3 exhibits antibacterial activity and may be used in production to combat diseases caused by bacteria in silkworm.

Fused Nickel(II) Porphyrins-Sensing of Toxic Anions and Selected Metal Ions Through Supramolecular Interactions

Ni(II) porphyrins having fused -NH group were synthesized and characterized by various spectroscopic techniques. The fused porphyrins 1 and 2 were used to detect species of opposite polarity. 1 was used to sense toxic anions viz. cyanide and fluoride ions whereas 2 was used for detecting some selective metal ions including toxic mercury(II) ions. 1 is having acidic -NH proton, which detects anions via hydrogen bonding interactions followed by anion-induced deprotonation. On the other hand, 2 senses the metal species via weak charge transfer interactions from oxygen atom of the formyl group to the added metal ions. The limit of detection was calculated in case of 1 as 2.13 and 3.15 ppm for cyanide and fluoride ions, respectively. Similarly, the detection limit was found to be 0.930, 2.231, and 0.718 ppm for Cu(II), Fe(III), and Hg(II) ions, respectively, for probe 2. The probes were recovered and reused for several cycles.

Metabolism Regulation and Redox State: Insight into the Role of Superoxide Dismutase 1

Energy metabolism and redox state are strictly linked; energy metabolism is a source of reactive oxygen species (ROS) that, in turn, regulate the flux of metabolic pathways. Moreover, to assure redox homeostasis, metabolic pathways and antioxidant systems are often coordinately regulated. Several findings show that superoxide dismutase 1 (SOD1) enzyme has effects that go beyond its superoxide dismutase activity and that its functions are not limited to the intracellular compartment. Indeed, SOD1 is secreted through unconventional secretory pathways, carries out paracrine functions and circulates in the blood bound to lipoproteins. Striking experimental evidence links SOD1 to the redox regulation of metabolism. Important clues are provided by the systemic effects on energy metabolism observed in mutant SOD1-mediated amyotrophic lateral sclerosis (ALS). The purpose of this review is to analyze in detail the involvement of SOD1 in redox regulation of metabolism, nutrient sensing, cholesterol metabolism and regulation of mitochondrial respiration. The scientific literature on the relationship between ALS, mutated SOD1 and metabolism will also be explored, in order to highlight the metabolic functions of SOD1 whose biological role still presents numerous unexplored aspects that deserve further investigation.

Serum Total Antioxidant Capacity and Enzymatic Defence of Dogs with Chronic Heart Failure and Atrial Fibrillation: A Preliminary Study

Introduction

Atrial fibrillation may potentially contribute to oxidative stress to a greater extent than chronic heart failure. The aim of the study was to compare the serum total antioxidant capacity and enzymatic antioxidant defence of dogs with chronic heart failure and atrial fibrillation with those of subjects with chronic heart failure and sinus rhythm and healthy controls.

Material and Methods

A total of 33 dogs were divided into three groups: dogs with chronic heart failure and atrial fibrillation (CHF + AF; n = 12), chronic heart failure and sinus rhythm (CHF + SR; n = 9), and healthy controls (n = 12). Serum total antioxidant capacity (TAC), serum CuZn-superoxide dismutase (SOD) and catalase, and plasma glutathione peroxidase (GPx) activity were determined.

Results

SOD activity and serum TAC were significantly lower in the study groups than in control animals. Catalase activity was significantly higher and plasma GPx activity significantly lower in dogs with CHF + AF compared with the CHF + SR and control dogs.

Conclusion

The results suggest that chronic heart failure in dogs significantly impacts the serum TAC and the antioxidant enzymatic defence, while plasma GPx activity is markedly lower in dogs with chronic heart failure and atrial fibrillation. The role of that imbalance needs further investigation.

Copper/Zinc Superoxide Dismutase in Human Skin: Current Knowledge

Superoxide dismutase is widespread in the human body, including skin and its appendages. Here, we focus on human skin copper/zinc superoxide dismutase, the enzyme that protects skin and its appendages against reactive oxygen species. Human skin copper/zinc superoxide dismutase resides in the cytoplasm of keratinocytes, where up to 90% of cellular reactive oxygen species is produced. Factors other than cell type, such as gender, age and diseased state influence its location in skin tissues. We review current knowledge of skin copper/zinc superoxide dismutase including recent studies in an attempt to contribute to solving the question of its remaining unexplained functions. The research described here may be applicable to pathologies associated with oxidative stress. However, recent studies on copper/zinc superoxide dismutase in yeast reveal that its predominant function may be in signaling pathways rather than in scavenging superoxide ions. If confirmed in the skin, novel approaches might be developed to unravel the enzyme's remaining mysteries.

Antioxidant defence and oxidative stress markers in cats with asymptomatic and symptomatic hypertrophic cardiomyopathy: a pilot study

Background

Hypertrophic cardiomyopathy is the most common cardiovascular cause of death in cats. Although the majority of cats remain asymptomatic, some may develop signs of chronic heart failure due to diastolic failure, arterial thromboembolism (ATE) or sudden cardiac death. Therefore, it is crucial to identify individuals that are in high risk of developing cardiac complications before the onset of life-threatening signs. Oxidative stress is the imbalance between the production and neutralisation of reactive oxygen species. Uncontrolled reactive oxygen species overproduction leads to protein and lipid peroxidation and damages the DNA strands, injuring the cells and leading to their death. The aim of the study was to evaluate the oxidative state in cats with hypertrophic cardiomyopathy and healthy controls.

Results

In total, 30 cats divided into three groups were assessed: animals with clinically evident hypertrophic cardiomyopathy (HCM; n = 8), subclinical hypertrophic cardiomyopathy (SUB-HCM; n = 11) and healthy controls (n = 11). The activity of superoxide dismutase was statistically significantly lower in animals with symptomatic and asymptomatic hypertrophic cardiomyopathy (HCM 0.99 ± 0.35 U/mL; SUB-HCM 1.39 ± 0.4 U/mL) compared to healthy cats (2.07 ± 0.76 U/mL, p < 0.01). The activity of catalase was significantly lower in the SUB-HCM group (19.4 ± 4.2 nmol/min/mL) compared to the HCM (23.6 ± 5.9 nmol/min/mL) and the control (30 ± 7.5 nmol/min/mL, p < 0.01) group. The activity of glutathione peroxidase was 4196 ± 353 nmol/min/mL in the HCM group, 4331 ± 451 nmol/min/mL in the SUB-HCM group and 4037 ± 341 nmol/min/mL in the control group and did not differ significantly between groups. The total antioxidant capacity of plasma was 602 ± 65.5 copper reducing equivalents (CRE) in the HCM group, 605.9 ± 39.9 CRE in the SUB-HCM group and 629 ± 77.5 CRE in the healthy cats and did not differ significantly between the groups.

Conclusions

Activities of superoxide dismutase and catalase differed in cats with hypertrophic cardiomyopathy, however the activity of the latter was only significantly lower in asymptomatic stage of the disease. The potentially beneficial effect of antioxidative substances on the disease progression in the asymptomatic and symptomatic stage of this disease should also be examined.

Vitreous Antioxidants, Degeneration, and Vitreo-Retinopathy: Exploring the Links

The transparent vitreous body, which occupies about 80% of the eye’s volume, is laden with numerous enzymatic and non-enzymatic antioxidants that could protect the eye from oxidative stress and disease. Aging is associated with degeneration of vitreous structure as well as a reduction in its antioxidant capacity. A growing body of evidence suggests these age-related changes may be the precursor of numerous oxidative stress-induced vitreo-retinopathies, including vision degrading myodesopsia, the clinically significant entoptic phenomena that can result from advanced vitreous degeneration. Adequate intravitreal antioxidant levels may be protective against vitreous degeneration, possibly preventing and even improving vision degrading myodesopsia as well as mitigating various other vitreo-retinopathies. The present article is, therefore, a review of the different antioxidant molecules within vitreous and the inter-relationships between vitreous antioxidant capacity and degeneration.

Anti-oxidative effects of superoxide dismutase 3 on inflammatory diseases

Free radicals and other oxidants are critical determinants of the cellular signaling pathways involved in the pathogenesis of several human diseases including inflammatory diseases. Numerous studies have demonstrated the protective effects of antioxidant enzymes during inflammation by elimination of free radicals. The superoxide dismutase (SOD), an antioxidant enzyme, plays an essential pathogenic role in the inflammatory diseases by not only catalyzing the conversion of the superoxide to hydrogen peroxide and oxygen but also affecting immune responses. There are three distinct isoforms of SOD, which distribute in different cellular compartments such as cytosolic SOD1, mitochondrial SOD2, and extracellular SOD3. Many studies have investigated the anti-oxidative effects of SOD3 in the inflammatory diseases. Herein, in this review, we focus on the current understanding of SOD3 as a therapeutic protein in inflammatory diseases such as skin, autoimmune, lung, and cardiovascular inflammatory diseases. Moreover, the mechanism(s) by which SOD3 modulates immune responses and signal initiation in the pathogenesis of the diseases will be further discussed.

[Regulation of Extracellular Redox Homeostasis in Tumor Microenvironment]

Excessive generation of reactive oxygen species (ROS) has been implicated in the progression of tumors. Superoxide dismutase 3 (SOD3) is a copper-containing secretory antioxidative enzyme that plays a critical role in redox homeostasis, particularly in extracellular spaces. Considerable evidence suggests that SOD3 protein expression is significantly decreased or lost in several tumor tissues, and this loss results in tumor metastasis. On the other hand, epigenetic disturbances, including DNA hyper-/hypomethylation, histone de/acetylation, and histone de/methylation, may be involved in tumorigenesis and the progression of metastasis. However, regulation of SOD3 in the tumor microenvironment and the involvement of epigenetics in its expression remain unclear. To elucidate the molecular mechanisms underlying SOD3 expression, we investigated the involvement of epigenetics, including DNA methylation and histone modifications, in its regulation in tumor cells and macrophages. SOD3 expression in human monocytic THP-1 cells and human lung cancer A549 cells was silenced by DNA hypermethylation within the SOD3 promoter region. Furthermore, the DNA demethylase, ten-eleven translocation 1, was shown for the first time to play a key role in regulation of DNA methylation within that region. We also demonstrated that myocyte enhancer factor 2 functioned as one of the transcription factors of SOD3 expression in THP-1 cells. Collectively, these novel results will contribute to the elucidation of epigenetic redox regulation, and may provide important insights into tumorigenesis and tumor metastasis.

Dual Role of Reactive Oxygen Species in Muscle Function: Can Antioxidant Dietary Supplements Counteract Age-Related Sarcopenia?

Sarcopenia is characterized by the progressive loss of skeletal muscle mass and strength. In older people, malnutrition and physical inactivity are often associated with sarcopenia, and, therefore, dietary interventions and exercise must be considered to prevent, delay, or treat it. Among the pathophysiological mechanisms leading to sarcopenia, a key role is played by an increase in reactive oxygen and nitrogen species (ROS/RNS) levels and a decrease in enzymatic antioxidant protection leading to oxidative stress. Many studies have evaluated, in addition to the effects of exercise, the effects of antioxidant dietary supplements in limiting age-related muscle mass and performance, but the data which have been reported are conflicting. In skeletal muscle, ROS/RNS have a dual function: at low levels they increase muscle force and adaptation to exercise, while at high levels they lead to a decline of muscle performance. Controversial results obtained with antioxidant supplementation in older persons could in part reflect the lack of univocal effects of ROS on muscle mass and function. The purpose of this review is to examine the molecular mechanisms underlying the dual effects of ROS in skeletal muscle function and the analysis of literature data on dietary antioxidant supplementation associated with exercise in normal and sarcopenic subjects.

Inhibition of Neointima Hyperplasia, Inflammation, and Reactive Oxygen Species in Balloon-Injured Arteries by HVJ Envelope Vector-Mediated Delivery of Superoxide Dismutase Gene

Extracellular superoxide dismutase (EC-SOD) has been implicated in regulation of vascular function but its underlying molecular mechanism is largely unknown. These two-step experiments investigate whether hemagglutinating virus of Japan envelope (HVJ-E) vector-mediated EC-SOD gene delivery might protect against neointima formation, vascular inflammation, and reactive oxygen species (ROS) generation, and also explore cell growth signaling pathways. The first in-vitro experiment was performed to assess the transfection efficacy and safety of HVJ-E compared to lipofectamine®. Results revealed that HVJ-E has higher transfection efficiency and lower cytotoxicity than those of lipofectamine®. Another in-vivo study initially used balloon denudation to rat carotid artery, then delivered EC-SOD cDNA through the vector of HVJ-E. Arterial section with H&E staining from the animals 14 days after balloon injury showed a significant reduction of intima-to-media area ratio in EC-SOD transfected arteries when compared with control (empty vector-transfected arteries) (p < 0.05). Arterial tissue with EC-SOD gene delivery also exhibited lower levels of ROS, as assessed by fluorescent microphotography with dihydroethidium staining. Quantitative RT-PCR revealed that EC-SOD gene delivery significantly diminished mRNA expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β (p < 0.05 in all comparisons). An immunoblotting assay from vascular smooth muscle cell (VSMC) cultures showed that the EC-SOD transfected group attenuated the activation of MEK1/2, ERK1/2, and Akt signaling significantly. In conclusion, EC-SOD overexpression by HVJ-E vector inhibits neointima hyperplasia, inflammation, and ROS level triggered by balloon injury. The modulation of cell growth-signaling pathways by EC-SOD in VSMCs might play an important role in these inhibitory effects.

Redox Mechanisms in Neurodegeneration: From Disease Outcomes to Therapeutic Opportunities

SIGNIFICANCE

Once considered to be mere by-products of metabolism, reactive oxygen, nitrogen and sulfur species are now recognized to play important roles in diverse cellular processes such as response to pathogens and regulation of cellular differentiation. It is becoming increasingly evident that redox imbalance can impact several signaling pathways. For instance, disturbances of redox regulation in the brain mediate neurodegeneration and alter normal cytoprotective responses to stress. Very often small disturbances in redox signaling processes, which are reversible, precede damage in neurodegeneration. Recent Advances: The identification of redox-regulated processes, such as regulation of biochemical pathways involved in the maintenance of redox homeostasis in the brain has provided deeper insights into mechanisms of neuroprotection and neurodegeneration. Recent studies have also identified several post-translational modifications involving reactive cysteine residues, such as nitrosylation and sulfhydration, which fine-tune redox regulation. Thus, the study of mechanisms via which cell death occurs in several neurodegenerative disorders, reveal several similarities and dissimilarities. Here, we review redox regulated events that are disrupted in neurodegenerative disorders and whose modulation affords therapeutic opportunities.

CRITICAL ISSUES

Although accumulating evidence suggests that redox imbalance plays a significant role in progression of several neurodegenerative diseases, precise understanding of redox regulated events is lacking. Probes and methodologies that can precisely detect and quantify in vivo levels of reactive oxygen, nitrogen and sulfur species are not available.

FUTURE DIRECTIONS

Due to the importance of redox control in physiologic processes, organisms have evolved multiple pathways to counteract redox imbalance and maintain homeostasis. Cells and tissues address stress by harnessing an array of both endogenous and exogenous redox active substances. Targeting these pathways can help mitigate symptoms associated with neurodegeneration and may provide avenues for novel therapeutics. Antioxid. Redox Signal. 30, 1450-1499.

Secretion of IL-1β From Monocytes in Gout Is Redox Independent

The pro-inflammatory cytokine interleukin-1β (IL-1β) plays important roles in immunity but is also implicated in autoimmune disease. The most well-established mechanism of IL-1β secretion is via activation of the NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome which requires an initial priming signal followed by an activating signal. However, the precise mechanism by which the inflammasome is activated remains unclear. The role of reactive oxygen species (ROS) in this process is contradictory, with some studies suggesting that ROS are crucial while others describe opposite effects. In this study, we evaluated the effects of oxidative stress on IL-1β secretion. Gout is a disease driven solely by IL-1β secretion in response to monosodium urate (MSU) crystals which form during periods of hyperuricemia and thus presents an opportunity to study factors contributing to IL-1β secretion. Sera and monocytes were isolated from patients with gout to determine whether differences in antioxidant status could explain the susceptibility of these individuals to gout attacks. In addition, sera and monocytes were collected from patients with chronic kidney disease (CKD) for comparison as this condition is associated with high levels of oxidative stress and disturbances in serum uric acid levels. There were differences in some aspects of antioxidant defenses in gout patients and these were mainly due to higher serum uric acid. Monocytes from gout patients were more responsive to priming, but not activation, of the NLRP3 inflammasome. However, expression of the components of the NLRP3 inflammasome were unaffected by priming or activation of the inflammasome, nor were these expression levels differentially regulated in gout patients. Inhibition of ROS by N-Acetyl Cysteine inhibited TLR2-induced priming of the NLRP3 inflammasome, but had no effect on MSU-induced activation. Together these findings demonstrate that oxidative stress only affects priming of the NLRP3 inflammasome but does not influence activation.

Carcinogenesis and Reactive Oxygen Species Signaling: Interaction of the NADPH Oxidase NOX1-5 and Superoxide Dismutase 1-3 Signal Transduction Pathways

SIGNIFICANCE

Reduction/oxidation (redox) balance could be defined as an even distribution of reduction and oxidation complementary processes and their reaction end products. There is a consensus that aberrant levels of reactive oxygen species (ROS), commonly observed in cancer, stimulate primary cell immortalization and progression of carcinogenesis. However, the mechanism how different ROS regulate redox balance is not completely understood. Recent Advances: In the current review, we have summarized the main signaling cascades inducing NADPH oxidase NOX1-5 and superoxide dismutase (SOD) 1-3 expression and their connection to cell proliferation, immortalization, transformation, and CD34+ cell differentiation in thyroid, colon, lung, breast, and hematological cancers.

CRITICAL ISSUES

Interestingly, many of the signaling pathways activating redox enzymes or mediating the effect of ROS are common, such as pathways initiated from G protein-coupled receptors and tyrosine kinase receptors involving protein kinase A, phospholipase C, calcium, and small GTPase signaling molecules.

FUTURE DIRECTIONS

The clarification of interaction of signal transduction pathways could explain how cells regulate redox balance and may even provide means to inhibit the accumulation of harmful levels of ROS in human pathologies.

Implications of plasma thiol redox in disease

Thiol groups are crucially involved in signaling/homeostasis through oxidation, reduction, and disulphide exchange. The overall thiol pool is the resultant of several individual pools of small compounds (e.g. cysteine), peptides (e.g. glutathione), and thiol proteins (e.g. thioredoxin (Trx)), which are not in equilibrium and present specific oxidized/reduced ratios. This review addresses mechanisms and implications of circulating plasma thiol/disulphide redox pools, which are involved in several physiologic processes and explored as disease biomarkers. Thiol pools are regulated by mechanisms linked to their intrinsic reactivity against oxidants, concentration of antioxidants, thiol-disulphide exchange rates, and their dynamic release/removal from plasma. Major thiol couples determining plasma redox potential (Eh) are reduced cysteine (CyS)/cystine (the disulphide form of cysteine) (CySS), followed by GSH/disulphide-oxidized glutathione (GSSG). Hydrogen peroxide and hypohalous acids are the main plasma oxidants, while water-soluble and lipid-soluble small molecules are the main antioxidants. The thiol proteome and thiol-oxidoreductases are emerging investigative areas given their specific disease-related responses (e.g. protein disulphide isomerases (PDIs) in thrombosis). Plasma cysteine and glutathione redox couples exhibit pro-oxidant changes directly correlated with ageing/age-related diseases. We further discuss changes in thiol-disulphide redox state in specific groups of diseases: cardiovascular, cancer, and neurodegenerative. These results indicate association with the disease states, although not yet clear-cut to yield specific biomarkers. We also highlight mechanisms whereby thiol pools affect atherosclerosis pathophysiology. Overall, it is unlikely that a single measurement provides global assessment of plasma oxidative stress. Rather, assessment of individual thiol pools and thiol-proteins specific to any given condition has more solid and logical perspective to yield novel relevant information on disease risk and prognosis.