Dietary fats modulate methylmercury-mediated systemic oxidative stress and oxidative DNA damage in rats

2008 ◽  
Vol 46 (5) ◽  
pp. 1706-1720 ◽  
Author(s):  
Xiaolei Jin ◽  
Hing Man Chan ◽  
Eric Lok ◽  
Kamla Kapal ◽  
Marnie Taylor ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Dietary Fats ◽  
Systemic Oxidative Stress

scholarly journals Simultaneous Quantification of Mitochondrial DNA Damage and Copy Number in Circulating Blood: A Sensitive Approach to Systemic Oxidative Stress

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Sam W. Chan ◽  
Simone Chevalier ◽  
Armen Aprikian ◽  
Junjian Z. Chen
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Mitochondrial Dna ◽  
Copy Number ◽  
Structural Damage ◽  
Oxidative Dna Damage ◽  
Nuclear Dna ◽  
Blood Analysis ◽  
Systemic Oxidative Stress ◽  
Wide Range

Systemic oxidative stress is associated with a wide range of pathological conditions. Oxidative DNA damage is frequently measured in circulating lymphocytes. Mitochondrial DNA (mtDNA) is known to be more sensitive to oxidative damage than nuclear DNA but is rarely used for direct measurement of DNA damage in clinical studies. Based on the supercoiling-sensitive real-time PCR method, we propose a new approach for the noninvasive monitoring of systemic oxidative stress by quantifying the mtDNA structural damage and copy number change in isolated lymphocytes in a single test. We show that lymphocytes have significantly less mtDNA content and relatively lower baseline levels of damage than cancer cell lines. In anex vivochallenge experiment, we demonstrate, for the first time, that exogenous H2O2induces a significant increase in mtDNA damage in lymphocytes from healthy individuals, but no repair activity is observed after 1 h recovery. We further demonstrate that whole blood may serve as a convenient alternative to the isolated lymphocytes in mtDNA analysis. Thus, the blood analysis with the multiple mtDNA end-points proposed in the current study may provide a simple and sensitive test to interrogate the nature and extent of systemic oxidative stress for a broad spectrum of clinical investigations.

001. ORIGINS OF DNA DAMAGE IN SPERMATOZOA

2010 ◽  
Vol 22 (9) ◽  
pp. 1
Author(s):  
R. J. Aitken
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Sperm Nucleus ◽  
Human Spermatozoa ◽  
Environmental Toxicants ◽  
Apoptotic Pathway ◽  
Systemic Oxidative Stress ◽  
Risk Of Disease ◽  
Dna Strand

DNA damage is frequently encountered in the spermatozoa of sub-fertile male mammals and is correlated with a range of adverse clinical outcomes including impaired fertilization, disrupted embryonic development, increased rates of miscarriage and an enhanced risk of disease in the progeny. The etiology of DNA fragmentation in human spermatozoa is closely correlated with the appearance of oxidative base adducts and evidence of impaired chromatin remodelling during spermiogenesis. In light of these associations we propose a two step hypothesis for the origins of DNA damage in spermatozoa. In Step 1, a variety of intrinsic (diabetes, varicocele, testicular torsion, obesity) and extrinsic (radiofrequency electromagnetic radiation, heat, cigarette smoke, diet, environmental toxicants) factors collude to generate a state of oxidative stress in the testes. This stress impedes spermiogenesis resulting in the generation of spermatozoa with poorly remodelled chromatin. These defective cells readily default to an apoptotic pathway comprising motility loss, caspase activation, phosphatidylserine exteriorization and the production of reactive oxygen species (ROS) by the mitochondria. In Step 2, these mitochondrial ROS attack the spermatozoa inducing lipid peroxidation and oxidative DNA damage, which then leads to DNA strand breakage and cell death. Nucleases activated and released during the apoptotic process are denied access to the sperm nucleus because the unique physical architecture of this cell prevents it. For this reason, a majority of the DNA damage encountered in human spermatozoa is oxidative. Given the importance of oxidative stress in the etiology of DNA damage, there should be a significant therapeutic role for antioxidants in the treatment of this condition. Furthermore, if oxidative DNA damage in spermatozoa is providing a sensitive readout of systemic oxidative stress, the implications of these findings could stretch beyond our immediate goal of trying to minimize DNA damage in spermatozoa as a prelude to assisted conception therapy.

Serum of 8-OHdG as a potential biomarker of oxidative DNA damage in workers exposed to harmful working environments

2020 ◽  
pp. 783-783
Author(s):  
I. A. Umnyagina ◽  
L. A. Strakhova ◽  
T. V. Blinova
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Blood Serum ◽  
Oxidative Dna Damage ◽  
Working Environment ◽  
Working Environments ◽  
Potential Biomarker ◽  
High Level ◽  
Damage Marker

In the blood serum of 70% individuals exposed to harmful factors of the working environment, a high level of oxidative stress and the DNA damage marker 8-Hydroxy-2’-Deoxyguanosine (8-OHdG) were detected.

Abstract 424: Vascular Smooth Muscle Cell Expression of S100a12 in Vivo Induces Enhanced Oxidative Stress & Vascular Remodeling

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Marion Hofmann Bowman ◽  
Jeannine Wilk ◽  
Gene Kim ◽  
Yanmin Zhang ◽  
Jalees Rehman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Smooth Muscle ◽  
Vascular Remodeling ◽  
Oxidative Dna Damage ◽  
Fold Increase ◽  
Brdu Incorporation ◽  
Elastic Fibers ◽  
Nuclear Staining

S100A12 is a small calcium binding protein that is a signal transduction ligand of the receptor for advance glycation endproducts (RAGE). S100A12, like RAGE, is expressed in the vessel wall of atherosclerotic vasculature, particularly in smooth muscle cells (SMC). While RAGE has been extensively implicated in inflammatory states such as atherosclerosis, the role of S100A12 is less clear. We tested the hypothesis that expression of human S100A12 directly exacerbates vascular inflammation. Several lines of Bl6/J transgenic mice (tg) expressing human S100A12 in SMC under control of the SM22a promoter were generated. Primary aortic SMC from tg and wild type (wt) littermates were isolated and analyzed for (i) proliferation using MTS/Formazan Assay and BrdU incorporation, (ii) oxidative stress using using flow cytometry with MitoSOX antibody, oxidative DNA damage using immunofluorescence microscopy with anti-8-oxo-dG antibody, and NF-kB activation measured by EMSA and (iii) cytokine expression measured by IL-6 ELISA. Furthermore, the aortas from tg and wt mice were examined. Results: Tg but not wt SMC expressed S100A12 protein. Tg SMC had a significant 1.9 to 2.7 fold increase in conversion of MTS into Formazan at 24–96 hours likely reflective of increased metabolic activity since BrdU incorporation into DNA was less in tg compared to wt SMC (4% vs 21% positive BrdU nuclei, p <0.05). Tg SMC showed significantly higher levels of mitochondrial generated ROS, nuclear staining for oxidative DNA damage which was not detected in the nuclei of wt SMC’s, and a 2.5 fold increase in NFkB activity. IL-6 production at baseline was higher in tg SMC’s (615 vs 213 pg/ml, p< 0.05) and increased dramatically after LPS treatment (10 ng/ml) in tg SMC’s (2130 vs 415 pg/ml). Histologic examination of the thoracic aorta at 10 weeks of age revealed increased collagen deposition in the aortic media with fragmentation and disarray of elastic fibers. In vivo ultrasound revealed a progressive dilation of the aortic arch from age 10 weeks to 16 weeks of age (1.27 to 1.60 mm, p<0.05) in tg but not in wt littermate mice (1.30 to 1.33 mm, p=0.1). These data reveal the novel finding that targeted expression of human S100A12 in SMC modulates oxidative stress, inflammation and vascular remodeling.

ID: 140: KLOTHO, AN ANTI-AGING MOLECULE, REGULATES ALVEOLAR EPITHELIAL CELL MTDNA DAMAGE AND APOPTOSIS

2016 ◽  
Vol 64 (4) ◽  
pp. 961.1-961
Author(s):  
S Kim ◽  
P Cheresh ◽  
RP Jablonski ◽  
DW Kamp ◽  
M Eren ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Epithelial Cell ◽  
Pulmonary Fibrosis ◽  
Oxidative Dna Damage ◽  
Alveolar Epithelial Cell ◽  
Premature Aging ◽  
Protective Effects ◽  
Mtdna Damage ◽  
Alveolar Epithelial

RationaleConvincing evidence has emerged that impaired alveolar epithelial cell (AEC) injury and repair resulting from ‘exaggerated’ lung aging and mitochondrial dysfunction are critical determinants of the lung fibrogenic potential of toxic agents, including asbestos fibers, but the mechanisms underlying these findings is unknown. We showed that the extent of AEC mitochondrial DNA (mtDNA) damage and apoptosis are critical determinants of asbestos-induced pulmonary fibrosis (Cheresh et al AJRCMB 2014, Kim et al JBC 2014). Klotho is an age-inhibiting gene and Klotho-deficient mice demonstrate a premature aging phenotype that includes a reduced lifespan, arteriosclerosis, and lung oxidative DNA damage, and that Klotho attenuates hyperoxic-induced AEC DNA damage and apoptosis (Ravikumar et al AJP-Lung 2014). We reason that Klotho has an important role in limiting pulmonary fibrosis by protecting the AECs from oxidative stress.MethodsQuantitative PCR-based measurement of mtDNA damage was assessed following transient transfection with wild-type Klotho, Klotho siRNA or AKT siRNA in A549 and/or MLE-12 cells for 48 hrs followed by exposure to either amosite asbestos (25 µg/cm2) or H2O2 (200 µM) for 24 hrs. Apoptosis was assessed by cleaved caspase-9/3 levels and DNA fragmentation assay. Murine pulmonary fibrosis was analyzed in male 8–10 week old WT (C3H/C57B6J) mice or Klotho heterozygous knockout (Kl+/−) mice following intratracheal instillation of a single dose of 100 µg crocidolite asbestos or titanium dioxide (negative control) using histology (fibrosis score by Masson's trichrome staining) and lung collagen (Sircoll assay).ResultsCompared to control, amosite asbestos or H2O2 reduces Klotho mRNA/protein expression. Notably, silencing of Klotho promotes oxidative stress-induced AEC mtDNA damage and apoptosis whereas Klotho-enforced expression (EE) and Euk-134, a mitochondrial ROS scavenger, are protective. Interestingly, Kl+/− mice have increased asbestos-induced lung fibrosis. Also, we find that inhibition or silencing of AKT augments oxidant-induced AEC mtDNA damage and apoptosis.ConclusionsOur data demonstrate a crucial role for AEC AKT signaling in mediating the mtDNA damage protective effects of Klotho. Given the importance of AEC aging and apoptosis in pulmonary fibrosis, we reason that Klotho/AKT axis is an innovative therapeutic target for preventing common lung diseases of aging (i.e. IPF, COPD, lung cancer, etc.) for which more effective management regimens are clearly needed.FundingNIH-RO1 ES020357-01A1 (DK) and VA Merit (DK).

scholarly journals Small molecule inhibitor of OGG1 blocks oxidative DNA damage repair at telomeres and potentiates Methotrexate anticancer effects

2020 ◽  
Author(s):  
Juan Miguel Baquero ◽  
Carlos Benítez-Buelga ◽  
Varshni Rajagopal ◽  
Zhao Zhenjun ◽  
Raúl Torres-Ruiz ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Cell Lines ◽  
Small Molecule ◽  
Oxidative Dna Damage ◽  
Genome Instability ◽  
Excision Repair ◽  
Small Molecule Inhibitor ◽  
Osteosarcoma Cell ◽  
Molecule Inhibitor

Abstract Background: The most common oxidative DNA lesion is 8-oxoguanine (8-oxoG) which is mainly recognized and excised by the glycosylase OGG1, initiating the Base Excision Repair (BER) pathway. Telomeres are particularly sensitive to oxidative stress which disrupts telomere homeostasis triggering genome instability. Methods: We used U2OS OGG1-GFP osteosarcoma cell line to study the role of OGG1 at the telomeres in response to oxidative stress. Next, we investigated the effects of inactivating pharmacologically the BER during oxidative stress (OS) conditions by using a specific small molecule inhibitor of OGG1 (TH5487) in different human cell lines. Results: We have found that during OS, TH5487 effectively blocks BER initiation at telomeres causing accumulation of oxidized bases at this region, correlating with other phenotypes such as telomere losses, micronuclei formation and mild proliferation defects. Besides, the antimetabolite Methotrexate synergizes with TH5487 through induction of intracellular ROS formation, which potentiates TH5487 mediated telomere and genome instability in different cell lines. Conclusions: Our findings demonstrate that OGG1 is required to protect telomeres from OS and present OGG1 inhibitors as a tool to induce oxidative DNA damage at telomeres, with the potential for developing new combination therapies for cancer treatment.

scholarly journals Oxidative lipid, protein, and DNA damage as oxidative stress markers in vascular complications of diabetes mellitus

2011 ◽  
Vol 34 (3) ◽  
pp. 163 ◽  
Author(s):  
Omur Tabak ◽  
Remise Gelisgen ◽  
Hayriye Erman ◽  
Fusun Erdenen ◽  
Cüneyt Muderrisoglu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetes Mellitus ◽  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Vascular Complications ◽  
Diabetic Group ◽  
Control Group ◽  
Diabetic Patients ◽  
Serum Samples ◽  
Type 2 Diabetic Patients

Purpose: The purpose of this study was to determine the effects of diabetic complications on oxidation of proteins, lipids, and DNA and to investigate the relationship between oxidative damage markers and clinical parameters. Methods: The study group consisted of 69 type 2 diabetic patients (20 patients without complication, 49 patients with complication) who attended internal medicine outpatient clinics of Istanbul Education and Research Hospital and 19 healthy control subjects. In serum samples of both diabetic patients and healthy subjects, 8-hydroxy-2’deoxyguanosine (8-OHdG), as a marker of oxidative DNA damage, Nε-(hexanoyl)lysine (HEL) and 15-F2t-iso-prostaglandin (15-F2t-IsoP). as products of lipooxidative damage, advanced oxidation protein products (AOPP), as markers of protein damage, and paraoxonase1 (PON1) as antioxidant were studied. Results: 15-F2t-IsoP (p < 0.005) and AOPP (p < 0.001) levels were significantly higher in diabetic group than control group while there were no significant differences in levels of 8-OHdG and HEL between the two groups. AOPP (p < 0.001) and 8-OHdG (p < 0.001) were significantly higher in diabetic group with complications compared to diabetic group without complications. Conclusions: Increased formation of free radicals and oxidative stress, under conditions of hyperglycaemia, is one of the probable causes for evolution of complications in diabetes mellitus. Our study supports the hypothesis that oxidant/antioxidant balance is disturbed in diabetic patients.

Paternal impacts on development: identification of genomic regions vulnerable to oxidative DNA damage in human spermatozoa

2019 ◽  
Vol 34 (10) ◽  
pp. 1876-1890 ◽  
Author(s):  
M J Xavier ◽  
B Nixon ◽  
S D Roman ◽  
R J Scott ◽  
J R Drevet ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Male Infertility ◽  
Oxidative Damage ◽  
Oxidative Dna Damage ◽  
Human Spermatozoa ◽  
Research Centre ◽  
Environmental Toxicants ◽  
Next Generation ◽  
Genomic Regions

Abstract STUDY QUESTION Do all regions of the paternal genome within the gamete display equivalent vulnerability to oxidative DNA damage? SUMMARY ANSWER Oxidative DNA damage is not randomly distributed in mature human spermatozoa but is instead targeted, with particular chromosomes being especially vulnerable to oxidative stress. WHAT IS KNOWN ALREADY Oxidative DNA damage is frequently encountered in the spermatozoa of male infertility patients. Such lesions can influence the incidence of de novo mutations in children, yet it remains to be established whether all regions of the sperm genome display equivalent susceptibility to attack by reactive oxygen species. STUDY DESIGN, SIZE, DURATION Human spermatozoa obtained from normozoospermic males (n = 8) were split into equivalent samples and subjected to either hydrogen peroxide (H2O2) treatment or vehicle controls before extraction of oxidized DNA using a modified DNA immunoprecipitation (MoDIP) protocol. Specific regions of the genome susceptible to oxidative damage were identified by next-generation sequencing and validated in the spermatozoa of normozoospermic males (n = 18) and in patients undergoing infertility evaluation (n = 14). PARTICIPANTS/MATERIALS, SETTING, METHODS Human spermatozoa were obtained from normozoospermic males and divided into two identical samples prior to being incubated with either H2O2 (5 mm, 1 h) to elicit oxidative stress or an equal volume of vehicle (untreated controls). Alternatively, spermatozoa were obtained from fertility patients assessed as having high basal levels of oxidative stress within their spermatozoa. All semen samples were subjected to MoDIP to selectively isolate oxidized DNA, prior to sequencing of the resultant DNA fragments using a next-generation whole-genomic sequencing platform. Bioinformatic analysis was then employed to identify genomic regions vulnerable to oxidative damage, several of which were selected for real-time quantitative PCR (qPCR) validation. MAIN RESULTS AND THE ROLE OF CHANCE Approximately 9000 genomic regions, 150–1000 bp in size, were identified as highly vulnerable to oxidative damage in human spermatozoa. Specific chromosomes showed differential susceptibility to damage, with chromosome 15 being particularly sensitive to oxidative attack while the sex chromosomes were protected. Susceptible regions generally lay outside protamine- and histone-packaged domains. Furthermore, we confirmed that these susceptible genomic sites experienced a dramatic (2–15-fold) increase in their burden of oxidative DNA damage in patients undergoing infertility evaluation compared to normal healthy donors. LIMITATIONS, REASONS FOR CAUTION The limited number of samples analysed in this study warrants external validation, as do the implications of our findings. Selection of male fertility patients was based on high basal levels of oxidative stress within their spermatozoa as opposed to specific sub-classes of male factor infertility. WIDER IMPLICATIONS OF THE FINDINGS The identification of genomic regions susceptible to oxidation in the male germ line will be of value in focusing future analyses into the mutational load carried by children in response to paternal factors such as age, the treatment of male infertility using ART and paternal exposure to environmental toxicants. STUDY FUNDING/COMPETING INTEREST(S) Project support was provided by the University of Newcastle’s (UoN) Priority Research Centre for Reproductive Science. M.J.X. was a recipient of a UoN International Postgraduate Research Scholarship. B.N. is the recipient of a National Health and Medical Research Council of Australia Senior Research Fellowship. Authors declare no conflict of interest.

scholarly journals The Radiosensitizing Effect of Zinc Oxide Nanoparticles in Sub-Cytotoxic Dosing Is Associated with Oxidative Stress In Vitro

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4062
Author(s):  
Till Jasper Meyer ◽  
Agmal Scherzad ◽  
Helena Moratin ◽  
Thomas Eckert Gehrke ◽  
Julian Killisperger ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Oxidative Dna Damage ◽  
Clonogenic Survival ◽  
Oxide Nanoparticles ◽  
Radiosensitizing Effect ◽  
Primary Fibroblasts

Radioresistance is an important cause of head and neck cancer therapy failure. Zinc oxide nanoparticles (ZnO-NP) mediate tumor-selective toxic effects. The aim of this study was to evaluate the potential for radiosensitization of ZnO-NP. The dose-dependent cytotoxicity of ZnO-NP20 nm and ZnO-NP100 nm was investigated in FaDu and primary fibroblasts (FB) by an MTT assay. The clonogenic survival assay was used to evaluate the effects of ZnO-NP alone and in combination with irradiation on FB and FaDu. A formamidopyrimidine-DNA glycosylase (FPG)-modified single-cell microgel electrophoresis (comet) assay was applied to detect oxidative DNA damage in FB as a function of ZnO-NP and irradiation exposure. A significantly increased cytotoxicity after FaDu exposure to ZnO-NP20 nm or ZnO-NP100 nm was observed in a concentration of 10 µg/mL or 1 µg/mL respectively in 30 µg/mL of ZnO-NP20 nm or 20 µg/mL of ZnO-NP100 nm in FB. The addition of 1, 5, or 10 µg/mL ZnO-NP20 nm or ZnO-NP100 nm significantly reduced the clonogenic survival of FaDu after irradiation. The sub-cytotoxic dosage of ZnO-NP100 nm increased the oxidative DNA damage compared to the irradiated control. This effect was not significant for ZnO-NP20 nm. ZnO-NP showed radiosensitizing properties in the sub-cytotoxic dosage. At least for the ZnO-NP100 nm, an increased level of oxidative stress is a possible mechanism of the radiosensitizing effect.

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