Functional diversification of five superoxide dismutase genes in Aspergillus nidulans against oxidative stress: distinct cellular roles of SodA and SodB.

Breast cancer (BC) is the primary cause of cancer-related death among women globally, highlighting the importance of the identification of novel biomarkers for early detection and prognosis. This study investigates the impact of NOS3 (endothelial nitric oxide synthase) and SOD1 (superoxide dismutase 1) gene polymorphisms on BC development, focusing on their associations with oxidative stress and tumor progression. A case-control study involving 30 BC patients and 30 healthy controls was conducted. Mutations in NOS3 and SOD1 genes were identified using sanger sequencing. ELISA was used to measure oxidative stress markers such peroxynitrite (ONOO-) and superoxide dismutase (SOD). To investigate functional associations, protein-protein interaction networks were examined using the GENEMANIA database. The study identified 32 polymorphisms in the NOS3 gene and 16 polymorphisms in the SOD1 gene, as well as nine amino acids alterations predicted in SOD1 gene. In comparison to controls, BC patients had higher levels of ONOO- (0.095 ± 0.048 ng/L vs. 0.048 ± 0.057 ng/L, p < 0.0001) and SOD (0.074 ± 0.033 ng/ml vs. 0.043 ± 0.045 ng/ml, p < 0.001). GENEMANIA analysis showed the interactions among NOS3, SOD1, and oxidative stress-related genes, highlighting their significance in cellular redox balance. These findings suggest that NOS3 and SOD1 polymorphisms may contribute to BC pathogenesis, as supported by the observed oxidative stress alterations (ONOO- and SOD levels). Additional validation in larger cohorts is needed to confirm their potential as biomarkers for risk evaluation and clinical advancement. The study enhances understanding of the genetic and oxidative stress mechanisms in cancer biology and identifies potential therapeutic targets for further investigation.

Elucidating the mode of action of fungicides and the mechanism of fungicide resistance is a promising scientific approach to plant protection. However, the fungicidal mode of action or the mechanism of fungicide resistance has not been elucidated for all new fungicides. Furthermore, the mode of the action has not been fully elucidated for some fungicides that have long been on the market. Dicarboximide fungicides, one of the classes of fungicides dealt with in this paper, have also commercially available for a long time. Several theories have been proposed regarding their mode of action, but their bona fide fungicidal mechanism has not been fully elucidated. Fungi, including phytopathogenic fungi, usually develop thalli and their cells are directly exposed to the environment. The cells inevitably experience several kinds of environmental stresses throughout their life cycles. These stresses include water activity (osmotic) stress and oxidative stress caused by the host response in a host-parasite interaction. To sense and respond to these stresses, fungi possess signal transduction systems and adaptation mechanisms. In the last 10 years, information obtained in the field of genome science on budding yeast (Saccharomyces cerevisiae, a leading model organism in fungal science) has enabled us to elucidate signal transduction systems and adaptation mechanisms in filamentous fungi, and further progress led to the clarification of the mode of action of dicarboximide and phenylpyrrole fungicides. These fungicides are closely involved in an osmotic signaling system in filamentous fungi. The fungicides now constitute an essential tool for studying this system. And as a result, this system has attracted great attention as a target of new antifungal agents. Furthermore, in some fungi, this system is involved in the pathogenicity of their hosts. In this paper, we introduce researches on the mode of action of these fungicides, which lead to the identification of the osmotic signaling system in pathogenic filamentous fungi, and related findings.

Effects of experimentally induced maternal hypothyroidism and hyperthyroidism on the development of rat offspring: II—The developmental pattern of neurons in relation to oxidative stress and antioxidant defense system

Calorie Restriction Reduces Oxidative Stress by SIRT3-Mediated SOD2 Activation

5-Fluorouracil induces inflammation and oxidative stress in the major salivary glands affecting salivary flow and saliva composition

Background: Superoxide dismutase 1 (SOD1), the ubiquitously expressed and predominant superoxide dismutase, catalyzes the conversion of superoxide ions into hydrogen peroxide which will be further detoxified by catalase or glutathione peroxidase. The SOD1 gene has been reported to be over-expressed in human cancer cells, and targeting SOD1 has been proposed as a new strategy for cancer therapy. While the transcriptional regulation of the SOD1 gene has been well-characterized, the contribution of the SOD1 3′-UTR to SOD1 gene expression has not been previously examined in any model systems. Methods: The full length (325 bases) and different fragments of the SOD1 3′UTR were amplified from human cancer cells. Each of the amplified products was inserted into a pGL3-promoter reporter vector downstream of the luciferase cDNA. The reporter constructs were transfected into Panc-1 (pancreatic cancer), A2780 (ovarian cancer), and HepG2 (liver cancer) cells and luciferase activity was analyzed. The wild type pGL3-promoter vector and the antisense orientation of the SOD1 3′-UTR reporter construct served as controls. Luciferase mRNA stability was examined by reverse transcriptase real-time PCR. Western blot was performed to examine endogenous SOD1 protein expression levels. Results: The luciferase activity was 10 (HepG2) and 70 (A2780 and Panc-1) fold higher in cells transfected with the full-length SOD1 3′-UTR compared with those in control cells. The dramatically increased luciferase activity was likely attributed to enhanced luciferase mRNA stability as analyzed by real-time RT-PCR. Significantly reduced luciferase activities were found in cells transfected with the reporter constructs bearing different fragments of the SOD1 3′-UTR. Most noticeably, transfection with the reporter construct bearing a deletion of the first 200 bases of the SOD1 3′-UTR brought the reporter activity down to a level similar to that in controls. Further deletion analysis showed that the secondary structure of the SOD1 3′-UTR may also play a key role in SOD1 3′-UTR-mediated gene expression and the putative AU-rich elements are unlikely to confer the sustained SOD1 gene expression. Moreover, we found that the full-length SOD1 3′-UTR can serve as a decoy or competitor to attenuate endogenous SOD1 protein expression, indicating the involvement of trans-acting RNA binding factors in maintaining high expression of the SOD1 gene. Summary: The SOD1 3′-UTR maintains the high expression of the SOD1 gene in human cancer cells likely through increasing SOD1 mRNA stability. The interaction of the SOD1 3′-UTR with the trans-acting RNA binding proteins is required to maintain SOD1 gene expression. We are actively working on identifying these RNA binding proteins and their interacting cis-elements in the SOD1 3′-UTR in our model systems. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4194. doi:1538-7445.AM2012-4194

During their life cycle, proteins are subject to different modifications involving reactive oxygen species. Such oxidative damage to proteins may lead to the formation of insoluble aggregates and cytotoxicity and is associated with age-related disorders including neurodegenerative diseases, cancer, and diabetes. Superoxide dismutase 1 (SOD1), a key antioxidant enzyme in human cells, is particularly susceptible to such modifications. Moreover, this homodimeric metalloenzyme has been directly linked to both familial and sporadic amyotrophic lateral sclerosis (ALS), a devastating, late-onset motor neuronal disease, with more than 150 ALS-related mutations in the SOD1 gene. Importantly, oxidatively damaged SOD1 aggregates have been observed in both familial and sporadic forms of the disease. However, the molecular mechanisms as well as potential implications of oxidative stress in SOD1-induced cytotoxicity remain elusive. In this study, we examine the effects of oxidative modification on SOD1 monomer and homodimer stability, the key molecular properties related to SOD1 aggregation. We use molecular dynamics simulations in combination with thermodynamic integration to study microscopic-level site-specific effects of oxidative “mutations” at the dimer interface, including lysine, arginine, proline and threonine carbonylation, and cysteine oxidation. Our results show that oxidative damage of even single residues at the interface may drastically destabilize the SOD1 homodimer, with several modifications exhibiting a comparable effect to that of the most drastic ALS-causing mutations known. Additionally, we show that the SOD1 monomer stability decreases upon oxidative stress, which may lead to partial local unfolding and consequently to increased aggregation propensity. Importantly, these results suggest that oxidative stress may play a key role in development of ALS, with the mutations in the SOD1 gene being an additional factor.

Allelic variations in superoxide dismutase-1 (SOD1) gene and renal and cardiovascular morbidity and mortality in type 2 diabetic subjects

Agrobacterium-mediated transformation (AMT) was used to identify potential virulence factors in Sclerotinia sclerotiorum. Screening AMT transformants identified two mutants showing significantly reduced virulence. The mutants showed growth rate, sclerotial formation, and oxalate production similar to that of the wild type. The mutation was due to a single T-DNA insertion at 212 bp downstream of the Cu/Zn superoxide dismutase (SOD) gene (SsSOD1, SS1G_00699). Expression levels of SsSOD1 were significantly increased under oxidative stresses or during plant infection in the wild-type strain but could not be detected in the mutant. SsSOD1 functionally complemented the Cu/Zn SOD gene in a Δsod1 Saccharomyces cerevisiae mutant. The SOD mutant had increased sensitivity to heavy metal toxicity and oxidative stress in culture and reduced ability to detoxify superoxide in infected leaves. The mutant also had reduced expression levels of other known pathogenicity genes such as endo-polygalacturanases sspg1 and sspg3. The functions of SsSOD1 were further confirmed by SsSOD1-deletion mutation. Like the AMT insertion mutant, the SsSOD1-deletion mutant exhibited normal growth rate, sclerotial formation, oxalate production, increased sensitivity to metal and oxidative stress, and reduced virulence. These results suggest that SsSOD1, while not being required for saprophytic growth and completion of the life cycle, plays critical roles in detoxification of reactive oxygen species during host-pathogen interactions and is an important virulence factor of Sclerotinia sclerotiorum.

Although much progress has been made in the study of cell wall biosynthetic genes in the model filamentous fungus Aspergillus nidulans, there are still targets awaiting characterization. An example is the gene celA (ANIA_08444) encoding a putative mixed linkage glucan synthase. To characterize the role of celA, we deleted it in A. nidulans, analyzed the phenotype of the mycelium and performed RNA-Seq. The strain shows a very strong phenotype, namely “balloons” along the hyphae and aberrant conidiophores, as well as an altered susceptibility to cell wall drugs. These data suggest a potential role of the gene in cell wall-related processes. The Gene Ontology term Enrichment analysis shows increased expression of secondary metabolite biosynthetic genes (sterigmatocystin in particular) in the deleted strain. Our results show that the deletion of celA triggers a strong phenotype reminiscent of cell wall-related aberrations and the upregulation of some secondary metabolite gene clusters in A. nidulans.

The cytochrome c gene (cycA) of the filamentous fungus Aspergillus nidulans has been isolated and sequenced. The gene is present in a single copy per haploid genome and encodes a polypeptide of 112 amino acid residues. The nucleotide sequence of the A. nidulans cycA gene shows 87% identity to the DNA sequence of the Neurospora crassa cytochrome c gene, and approximately 72% identity to the sequence of the Saccharomyces cerevisiae iso-1-cytochrome c gene (CYC1). The S. cerevisiae CYC1 gene was used as a heterologous probe to isolate the homologous gene in A. nidulans. The A. nidulans cytochrome c sequence contains two small introns. One of these is highly conserved in terms of position, but the other has not been reported in any of the cytochrome c genes so far sequenced. Expression of the cycA gene is not affected by glucose repression, but has been shown to be induced approximately tenfold in the presence of oxygen and three- to fourfold under heat-shock conditions.

The copper-containing superoxide dismutases (SODs) represent a large family of enzymes that participate in the metabolism of reactive oxygen species by disproportionating superoxide anion radical to oxygen and hydrogen peroxide. Catalysis is driven by the redox-active copper ion, and in most cases, SODs also harbor a zinc at the active site that enhances copper catalysis and stabilizes the protein. Such bimetallic Cu,Zn-SODs are widespread, from the periplasm of bacteria to virtually every organelle in the human cell. However, a new class of copper-containing SODs has recently emerged that function without zinc. These copper-only enzymes serve as extracellular SODs in specific bacteria (i.e. Mycobacteria), throughout the fungal kingdom, and in the fungus-like oomycetes. The eukaryotic copper-only SODs are particularly unique in that they lack an electrostatic loop for substrate guidance and have an unusual open-access copper site, yet they can still react with superoxide at rates limited only by diffusion. Copper-only SOD sequences similar to those seen in fungi and oomycetes are also found in the animal kingdom, but rather than single-domain enzymes, they appear as tandem repeats in large polypeptides we refer to as CSRPs (copper-only SOD-repeat proteins). Here, we compare and contrast the Cu,Zn versus copper-only SODs and discuss the evolution of copper-only SOD protein domains in animals and fungi.

ABSTRACTThe evolution of oxygenic photosynthesis during the Archean (4–2.5 Ga) required the presence of complementary reducing pathways to maintain the cellular redox balance. While the timing of the evolution of superoxide dismutases (SODs), enzymes that convert superoxide to hydrogen peroxide and O2, within bacteria and archaea is not resolved, the first SODs appearing in cyanobacteria contained copper and zinc in the reaction center (CuZnSOD). Here, we analyse growth characteristics, SOD gene expression (qRT‐PCR) and cellular enzyme activity in the deep branching strain, Pseudanabaena sp. PCC7367, previously demonstrated to release significantly more O2 under anoxic conditions. The observed significantly higher growth rates (p < 0.001) and protein and glycogen contents (p < 0.05) in anoxically cultured Pseudanabaena PCC7367 compared to control cultures grown under present‐day oxygen‐rich conditions prompted the following question: Is the growth of Pseudanabaena sp. PCC7367 correlated to atmospheric pO2 and cellular SOD activity? Expression of sodB (encoding FeSOD) and sodC (encoding CuZnSOD) strongly correlated with medium O2 levels (p < 0.001). Expression of sodA (encoding MnSOD) correlated significantly to SOD activity during the day (p = 0.019) when medium O2 concentrations were the highest. The cellular SOD enzyme activity of anoxically grown cultures was significantly higher (p < 0.001) 2 h before the onset of the dark phase compared to O2‐rich growth conditions. The expression of SOD encoding genes was significantly reduced (p < 0.05) under anoxic conditions in stirred cultures, as were medium O2 levels (p ≤ 0.001), compared to oxic‐grown cultures, whereas total cellular SOD activity remained comparable. Our data suggest that increasing pO2 negatively impacts the viability of early cyanobacteria, possibly by increasing photorespiration. Additionally, the increased expression of superoxide‐inactivating genes during the dark phase suggests the increased replacement rates of SODs under modern‐day conditions compared to those on early Earth.

The regulation of oxidative stress is an effective strategy for treating cancers. Therapeutic strategies for modulating an undesirable redox balance against cancers have included the enhancement of oxidative components, reducing the action of antioxidant systems, and the combined application of radiation and redox-modulating drugs. A precise understanding of redox regulation is required to treat different kinds of cancer. This review focuses on the redox regulation and oxidative stress defense systems of lung cancers. Thus, we highlighted several enzymatic antioxidant components, such as superoxide dismutase, catalase, heme oxygenase-1, peroxiredoxin, glutaredoxin, thioredoxin, thioredoxin reductase, glutathione peroxidase, and antioxidant components, including glutathione, nuclear factor erythroid 2-related factor 2, 8-oxo-7,8-dihydro-2'-deoxyguanosine, and mitochondrial citrate carrier SLC25A1, based on PubMed and Scopus-indexed literature. Understanding the oxidative stress defense system in lung cancer would be beneficial for developing and expanding therapeutic strategies, such as drug development, drug design, and advanced delivery platforms.

Protective effect of exopolysaccharides from lactic acid bacteria against amyloid beta1-42induced oxidative stress in SH-SY5Y cells: Involvement of the AKT, MAPK, and NF-κB signaling pathway