scholarly journals A multilayered repair system protects the mycobacterial chromosome from endogenous and antibiotic-induced oxidative damage

2020 ◽  
Vol 117 (32) ◽  
pp. 19517-19527
Author(s):  
Pierre Dupuy ◽  
Mir Howlader ◽  
Michael S. Glickman
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Dna Polymerases ◽  
Repair System ◽  
Genomic Integrity ◽  
Chromosomal Dna ◽  
Living Organisms ◽  
Oxidative Damage To Dna

Oxidative damage to DNA is a threat to the genomic integrity and coding accuracy of the chromosomes of all living organisms. Guanine is particularly susceptible to oxidation, and 8-oxo-dG (OG), when produced in situ or incorporated by DNA polymerases, is highly mutagenic due to mispairing with adenine. In many bacteria, defense against OG depends on MutT enzymes, which sanitize OG in the nucleotide pool, and the MutM/Y system, which counteracts OG in chromosomal DNA. InEscherichia coli, antibiotic lethality has been linked to oxidative stress and the downstream consequences of OG processing. However, in mycobacteria, the role of these systems in genomic integrity and antibiotic lethality is not understood, in part because mycobacteria encode four MutT enzymes and two MutMs, suggesting substantial redundancy. Here, we definitively probe the role of OG handling systems in mycobacteria. We find that, although MutT4 is the only MutT enzyme required for resistance to oxidative stress, this effect is not due to OG processing. We find that the dominant system that defends against OG-mediated mutagenesis is MutY/MutM1, and this system is dedicated to in situ chromosomal oxidation rather than correcting OG incorporated by accessory polymerases (DinB1/DinB2/DinB3/DnaE2). In addition, we uncover that mycobacteria resist antibiotic lethality through nucleotide sanitization by MutTs, and in the absence of this system, accessory DNA polymerases and MutY/M contribute to antibiotic-induced lethality. These results reveal a complex, multitiered system of OG handling in mycobacteria with roles in oxidative stress resistance, mutagenesis, and antibiotic lethality.

scholarly journals Influence of Metal-Resistant Staphylococcus aureus Strain K1 on the Alleviation of Chromium Stress in Wheat

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1354 ◽  
Author(s):  
Fanrong Zeng ◽  
Munazza Zahoor ◽  
Muhammad Waseem ◽  
Alia Anayat ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Anthropogenic Activities ◽  
Toxic Metal ◽  
Triticum Aestivum L ◽  
Aureus Strain ◽  
Peat Moss ◽  
Cr Toxicity ◽  
Living Organisms

Chromium (Cr) is recognized as a toxic metal that has detrimental effects on living organisms; notably, it is discharged into soil by various industries as a result of anthropogenic activities. Microbe-assisted phytoremediation is one of the most emergent and environmentally friendly methods used for the detoxification of pollutants. In this study, the alleviative role of Staphylococcus aureus strain K1 was evaluated in wheat (Triticum aestivum L.) under Cr stress. For this, various Cr concentrations (0, 25, 50 and 100 mg·kg−1) with and without peat-moss-based bacterial inoculum were applied in the soil. Results depicted that Cr stress reduced the plants’ growth by causing oxidative stress in the absence of S. aureus K1 inoculation. However, the application of S. aureus K1 regulated the plants’ growth and antioxidant enzymatic activities by reducing oxidative stress and Cr toxicity through conversion of Cr6+ to Cr3+. The Cr6+ uptake by wheat was significantly reduced in the S. aureus K1 inoculated plants. It can be concluded that the application of S. aureus K1 could be an effective approach to alleviate the Cr toxicity in wheat and probably in other cereals grown under Cr stress.

scholarly journals Effects of Caloric Restriction on Cardiac Oxidative Stress and Mitochondrial Bioenergetics: Potential Role of Cardiac Sirtuins

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ken Shinmura
Keyword(s):  
Oxidative Stress ◽  
Free Radical ◽  
Oxidative Damage ◽  
Caloric Restriction ◽  
Functional Decline ◽  
Cellular Damage ◽  
Free Radical Theory ◽  
Radical Theory ◽  
Stress Theory

The biology of aging has not been fully clarified, but the free radical theory of aging is one of the strongest aging theories proposed to date. The free radical theory has been expanded to the oxidative stress theory, in which mitochondria play a central role in the development of the aging process because of their critical roles in bioenergetics, oxidant production, and regulation of cell death. A decline in cardiac mitochondrial function associated with the accumulation of oxidative damage might be responsible, at least in part, for the decline in cardiac performance with age. In contrast, lifelong caloric restriction can attenuate functional decline with age, delay the onset of morbidity, and extend lifespan in various species. The effect of caloric restriction appears to be related to a reduction in cellular damage induced by reactive oxygen species. There is increasing evidence that sirtuins play an essential role in the reduction of mitochondrial oxidative stress during caloric restriction. We speculate that cardiac sirtuins attenuate the accumulation of oxidative damage associated with age by modifying specific mitochondrial proteins posttranscriptionally. Therefore, the distinct role of each sirtuin in the heart subjected to caloric restriction should be clarified to translate sirtuin biology into clinical practice.

scholarly journals Melatonin reduces oxidative damage in mouse granulosa cells via restraining JNK-dependent autophagy

Reproduction ◽  
2018 ◽  
Vol 155 (3) ◽  
pp. 307-319 ◽  
Author(s):  
Yan Cao ◽  
Ming Shen ◽  
Yi Jiang ◽  
Shao-chen Sun ◽  
Honglin Liu
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Mammalian Cells ◽  
Therapeutic Strategies ◽  
Oxygen Species ◽  
Protective Effects ◽  
Follicular Atresia ◽  
Direct Role ◽  
Jnk Pathway

Oxidative stress-induced granulosa cell (GCs) injury is believed to be a common trigger for follicular atresia. Emerging evidence indicates that excessive autophagy occurs in mammalian cells with oxidative damage. N-acetyl-5-methoxytrypamine (melatonin) has been shown to prevent GCs from oxidative injury, although the exact mechanism remains to be elucidated. Here, we first demonstrated that the suppression of autophagy through the JNK/BCL-2/BECN1 signaling is engaged in melatonin-mediated GCs protection against oxidative damage. Melatonin inhibited the loss of GCs viability, formation of GFP-MAP1LC3B puncta, accumulation of MAP1LC3B-II blots, degradation of SQSTM1 and the expression of BECN1, which was correlated with impaired activation of JNK during oxidative stress. On the other hand, blocking of autophagy and/or JNK also reduced the level of H2O2-induced GCs death, but failed to further restore GCs viability in the presence of melatonin. Particularly, the suppression of autophagy provided no additional protective effects when GCs were pretreated with JNK inhibitor and/or melatonin. Importantly, we found that the enhanced interaction between BCL-2 and BECN1 might be a responsive mechanism for autophagy suppression via the melatonin/JNK pathway. Moreover, blocking the downstream antioxidant system of melatonin using specific inhibitors further confirmed a direct role of melatonin/JNK/autophagy axis in preserving GCs survival without scavenging reactive oxygen species (ROS). Taken together, our findings uncover a novel function of melatonin in preventing GCs from oxidative damage by targeting JNK-mediated autophagy, which might contribute to develop therapeutic strategies for patients with ovulation failure-related disorders.

scholarly journals The Protective Role of Prenatal Alpha Lipoic Acid Supplementation against Pancreatic Oxidative Damage in Offspring of Valproic Acid-Treated Rats: Histological and Molecular Study

Biology ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 239
Author(s):  
Fatma M. Ghoneim ◽  
Hani Alrefai ◽  
Ayman Z. Elsamanoudy ◽  
Salwa M. Abo El-khair ◽  
Hanaa A. Khalaf
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Lipoic Acid ◽  
Caspase 3 ◽  
Protective Role ◽  
Alpha Lipoic Acid ◽  
Group Iii ◽  
Rat Offspring ◽  
Group I

Background: Sodium valproate (VPA) is an antiepileptic drug (AED) licensed for epilepsy and used during pregnancy in various indications. Alpha-lipoic acid (ALA) is a natural compound inducing endogenous antioxidant production. Our study aimed to investigate the effect of prenatal administration of VPA on the pancreas of rat offspring and assess the potential protective role of ALA co-administration during pregnancy. Methods: Twenty-eight pregnant female albino rats were divided into four groups: group I (negative control), group II (positive control, ALA treated), group III (VPA-treated), and group IV (VPA-ALA-treated). The pancreases of the rat offspring were removed at the fourth week postpartum and prepared for histological, immune-histochemical, morphometric, molecular, and oxidative stress marker studies. Results: In group III, there were pyknotic nuclei, vacuolated cytoplasm with ballooning of acinar, α, and β cells of the pancreas. Ultrastructural degeneration of cytoplasmic organelles was detected. Additionally, there was a significant increase in oxidative stress, a decrease in insulin-positive cell percentage, and an increase in glucagon positive cells in comparison to control groups. Moreover, VPA increased the gene expression of an apoptotic marker, caspase-3, with a decrease in anti-apoptotic Bcl2 and nuclear factor erythroid 2-related factor 2 (Nrf2) transcriptional factor. Conversely, ALA improved oxidative stress and apoptosis in group VI, and a consequent improvement of the histological and ultrastructure picture was detected. Conclusion: ALA co-administration with VPA significantly improved the oxidative stress condition, histological and morphometric picture of the pancreas, and restored normal expression of related genes, including Nrf2, caspase-3, and Bcl-2. Administration of α-lipoic acid has a protective effect against VPA-induced pancreatic oxidative damage via its cytoprotective antioxidant effect.

scholarly journals S-Allyl Cysteine Alleviates Hydrogen Peroxide Induced Oxidative Injury and Apoptosis through Upregulation of Akt/Nrf-2/HO-1 Signaling Pathway in HepG2 Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Chitra Basu ◽  
Runa Sur
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Oxidative Damage ◽  
Hepg2 Cells ◽  
Liver Diseases ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Dependent Manner ◽  
Cell Viability Assay

Hydrogen peroxide (H2O2) mediated oxidative stress leading to hepatocyte apoptosis plays a pivotal role in the pathophysiology of several chronic liver diseases. This study demonstrates that S-allyl cysteine (SAC) renders cytoprotective effects on H2O2 induced oxidative damage and apoptosis in HepG2 cells. Cell viability assay showed that SAC protected HepG2 cells from H2O2 induced cytotoxicity. Further, SAC treatment dose dependently inhibited H2O2 induced apoptosis via decreasing the Bax/Bcl-2 ratio, restoring mitochondrial membrane potential (∆Ψm), inhibiting mitochondrial cytochrome c release, and inhibiting proteolytic cleavage of caspase-3. SAC protected cells from H2O2 induced oxidative damage by inhibiting reactive oxygen species accumulation and lipid peroxidation. The mechanism underlying the antiapoptotic and antioxidative role of SAC is the induction of the heme oxygenase-1 (HO-1) gene in an NF-E2-related factor-2 (Nrf-2) and Akt dependent manner. Specifically SAC was found to induce the phosphorylation of Akt and enhance the nuclear localization of Nrf-2 in cells. Our results were further confirmed by specific HO-1 gene knockdown studies which clearly demonstrated that HO-1 induction indeed played a key role in SAC mediated inhibition of apoptosis and ROS production in HepG2 cells, thus suggesting a hepatoprotective role of SAC in combating oxidative stress mediated liver diseases.

scholarly journals PARK7 Diminishes Oxidative Stress-Induced Mucosal Damage in Celiac Disease

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Apor Veres-Székely ◽  
Mária Bernáth ◽  
Domonkos Pap ◽  
Réka Rokonay ◽  
Beáta Szebeni ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Adhesion ◽  
Epithelial Cells ◽  
Oxidative Damage ◽  
Duodenal Mucosa ◽  
Immunofluorescent Staining ◽  
Intracellular Accumulation ◽  
Mucosal Integrity ◽  
Small Intestinal

Coeliac disease (CD) is a chronic, immune-mediated small intestinal enteropathy, accompanied with gluten-triggered oxidative damage of duodenal mucosa. Previously, our research group reported an increased mucosal level of the antioxidant protein Parkinson’s disease 7 (PARK7) in children with CD. In the present study, we investigated the role of increased PARK7 level on the epithelial cell and mucosal integrity of the small intestine. The presence of PARK7 was investigated using immunofluorescent staining on duodenal mucosa of children with CD and on FHs74Int duodenal epithelial cells. To investigate the role of oxidative stress, FHs74Int cells were treated with H2O2 in the absence or presence of Comp23, a PARK7-binding compound. Intracellular accumulation of reactive oxygen species (ROS) was determined by DCFDA-based assay. Cell viability was measured by MTT, LDH, and Annexin V apoptosis assays. Disruption of cytoskeleton and cell adhesion was investigated by immunofluorescence staining and by real-time RT PCR. Effect of PARK7 on mucosal permeability was investigated ex vivo using intestinal sacs derived from control and Comp-23-pretreated mice. Comp23 treatment reduced the H2O2-induced intracellular accumulation of ROS, thus preserving the integrity of the cytoskeleton and also the viability of the FHs74Int cells. Accordingly, Comp23 treatment increased the expression of antioxidants (NRF2, TRX1, GCLC, HMOX1, NQO1), cell-cycle regulators (TP53, CDKN1A, PCNA, BCL2, BAX), and cell adhesion molecules (ZO1, CDH1, VCL, ITGB5) of H2O2-treated cells. Pretreatment with Comp23 considerably decreased the small intestinal permeability. In this study, we demonstrate that PARK7-binding Comp23 reduces the oxidative damage of duodenal epithelial cells, via increased expression of NRF2- and P53-regulated genes. Our results suggest that PARK7 plays a significant role in the maintenance of mucosal integrity in CD.

scholarly journals The Redox System inC. elegans, a Phylogenetic Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Andrew D. Johnston ◽  
Paul R. Ebert
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Cellular Damage ◽  
Future Research ◽  
Homologous Proteins ◽  
Redox Biology ◽  
Redox Signalling ◽  
C Elegans ◽  
Age Related

Oxidative stress is a toxic state caused by an imbalance between the production and elimination of reactive oxygen species (ROS). ROS cause oxidative damage to cellular components such as proteins, lipids, and nucleic acids. While the role of ROS in cellular damage is frequently all that is noted, ROS are also important in redox signalling. The “Redox Hypothesis" has been proposed to emphasize a dual role of ROS. This hypothesis suggests that the primary effect of changes to the redox state is modified cellular signalling rather than simply oxidative damage. In extreme cases, alteration of redox signalling can contribute to the toxicity of ROS, as well as to ageing and age-related diseases. The nematode speciesCaenorhabditis elegansprovides an excellent model for the study of oxidative stress and redox signalling in animals. We use protein sequences from central redox systems inHomo sapiens,Drosophila melanogaster, andSaccharomyces cerevisiaeto query Genbank for homologous proteins inC. elegans. We then use maximum likelihood phylogenetic analysis to compare protein families betweenC. elegansand the other organisms to facilitate future research into the genetics of redox biology.

Acute and severe hypobaric hypoxia-induced muscle oxidative stress in mice: the role of glutathione against oxidative damage

2004 ◽  
Vol 91 (2-3) ◽  
pp. 185-191 ◽  
Author(s):  
Jos� Magalh�es ◽  
Jos� M. C. Soares ◽  
Maria J. Neuparth ◽  
Rita Ferreira ◽  
Jos� Oliveira ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Hypobaric Hypoxia ◽  
Severe Hypobaric Hypoxia

scholarly journals Lycopene Treatment Ameliorates Amyloid Plaque Deposition and Memory Impairment in the APP/PS1 Mice

2021 ◽  
Author(s):  
Shanshan Ou ◽  
Yinchao Fang ◽  
Tong Wu ◽  
Jie Xu ◽  
Kaihua Guo
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Western Blot ◽  
Chronic Inflammation ◽  
Signal Pathway ◽  
Qualitative Assessment ◽  
Cell Cytotoxicity ◽  
Rt Pcr

Abstract Alzheimer’s disease (AD) is a neurodegenerative condition associated with oxidative stress and neuroinflammation. Lycopene has previously been shown to ameliorate neuroinflammation and exert protection against oxidative damage in neuroblastoma cells. The role of this compound in reversing cognitive dysfunction in AD has yet to be determined. The present study investigates the role of lycopene in AD with an in vitro Aβ1-42-induced cell cytotoxicity model as well as the in vivo APP/PS1 mouse model. The activation of Nrf2 signal pathway was assessed using western blot and RT-PCR. MDA, 8-OHdG, ROS, SOD, GHS and GSSG measurements were carried out using the specialized assay kits. The Morris water maze was used to examine qualitative assessment of memory and spatial learning. Immunofluorescence was used to visualize astrocytes and microglia activation as well as brain β-amyloid (Aβ) deposition. The NeuN positive cells were detected by immunofluorescence and western blot. Levels of cerebral cytokines were quantified using RT-PCR. Lycopene ameliorates oxidative damage in the Aβ1-42-triggered cell cytotoxicity model via Nrf2-ARE signal pathway activation, which is regulated by AKT-GSK3β pathway. In addition, lycopene improves the cognitive impairment and reduces the Aβ deposition. Mechanistically, lycopene attenuates neuron loss, decreases chronic inflammation and activates cerebral Nrf2-ARE signaling pathway in APP/PS1 mice. The results suggest that lycopene alleviates oxidative stress via AKT- Nrf2-ARE pathway. And early administration of lycopene improves cognitive deficits by reducing Aβ deposition, neuronal loss and decreasing the degree of chronic inflammation.

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