scholarly journals APE2 Zf-GRF facilitates 3′-5′ resection of DNA damage following oxidative stress

2016 ◽  
Vol 114 (2) ◽  
pp. 304-309 ◽  
Author(s):  
Bret D. Wallace ◽  
Zachary Berman ◽  
Geoffrey A. Mueller ◽  
Yunfeng Lin ◽  
Timothy Chang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Nucleic Acid ◽  
Oxidative Dna Damage ◽  
Strand Break ◽  
Binding Activity ◽  
Nucleic Acid Binding ◽  
Catalytic Core ◽  
Single Strand Break ◽  
X Ray

The Xenopus laevis APE2 (apurinic/apyrimidinic endonuclease 2) nuclease participates in 3′-5′ nucleolytic resection of oxidative DNA damage and activation of the ATR-Chk1 DNA damage response (DDR) pathway via ill-defined mechanisms. Here we report that APE2 resection activity is regulated by DNA interactions in its Zf-GRF domain, a region sharing high homology with DDR proteins Topoisomerase 3α (TOP3α) and NEIL3 (Nei-like DNA glycosylase 3), as well as transcription and RNA regulatory proteins, such as TTF2 (transcription termination factor 2), TFIIS, and RPB9. Biochemical and NMR results establish the nucleic acid-binding activity of the Zf-GRF domain. Moreover, an APE2 Zf-GRF X-ray structure and small-angle X-ray scattering analyses show that the Zf-GRF fold is typified by a crescent-shaped ssDNA binding claw that is flexibly appended to an APE2 endonuclease/exonuclease/phosphatase (EEP) catalytic core. Structure-guided Zf-GRF mutations impact APE2 DNA binding and 3′-5′ exonuclease processing, and also prevent efficient APE2-dependent RPA recruitment to damaged chromatin and activation of the ATR-Chk1 DDR pathway in response to oxidative stress in Xenopus egg extracts. Collectively, our data unveil the APE2 Zf-GRF domain as a nucleic acid interaction module in the regulation of a key single-strand break resection function of APE2, and also reveal topologic similarity of the Zf-GRF to the zinc ribbon domains of TFIIS and RPB9.

scholarly journals Metal Ions Modify in Vitro DNA Damage Yields With High-LET Radiation

2021 ◽  
Author(s):  
Dylan Buglewicz ◽  
Cathy Su ◽  
Austin Banks ◽  
Jazmine Strenger-smith ◽  
Suad Elmegerhi ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Strand Break ◽  
Single Strand ◽  
Iron Ion ◽  
Single Strand Break ◽  
Carbon Ion ◽  
X Ray ◽  
High Let ◽  
Break Formation

Abstract Cu2+ and Co2+ are metals known to increase DNA damage in the presence of hydrogen peroxide through a Fenton type reaction. We hypothesized that these metals could increase DNA damage following irradiations of increasing LET values as hydrogen peroxide is a product of the radiolysis of water. The reaction mixtures contain either double- or single-stranded DNA in solution with Cu2+ or Co2+ and was irradiated either with X-ray, carbon-ion or iron-ion beams or was treated with hydrogen peroxide or bleomycin at increasing radiation dosages or chemical concentrations. DNA damage was then assessed by gel electrophoresis followed by band intensity analysis. DNA in solution with metals demonstrated the most DNA damage when treated with hydrogen peroxide followed by irradiation with low-LET (X-Ray), high-LET (carbon-ion and iron-ion), respectively, and demonstrated the least damage with treatment of bleomycin. Cu2+ portrayed greater DNA damage than Co2+ following all experimental conditions. The metals effect caused more DNA damage and was observed to be LET dependent for single-strand break formation but inversely dependent for double-strand break formation. These results suggest that Cu2+ is more efficient than Co2+ at inducing both DNA single-strand and double-strand breaks following all irradiations and chemical treatments.

scholarly journals Senataxin, defective in ataxia oculomotor apraxia type 2, is involved in the defense against oxidative DNA damage

2007 ◽  
Vol 177 (6) ◽  
pp. 969-979 ◽  
Author(s):  
Amila Suraweera ◽  
Olivier J. Becherel ◽  
Philip Chen ◽  
Natalie Rundle ◽  
Rick Woods ◽  
...  
Keyword(s):  
Dna Damage ◽  
Autosomal Recessive ◽  
Oxidative Dna Damage ◽  
Strand Break ◽  
Full Length ◽  
Dna Double Strand Breaks ◽  
Single Strand Break ◽  
Oculomotor Apraxia ◽  
Single Strand Break Repair

Adefective response to DNA damage is observed in several human autosomal recessive ataxias with oculomotor apraxia, including ataxia-telangiectasia. We report that senataxin, defective in ataxia oculomotor apraxia (AOA) type 2, is a nuclear protein involved in the DNA damage response. AOA2 cells are sensitive to H2O2, camptothecin, and mitomycin C, but not to ionizing radiation, and sensitivity was rescued with full-length SETX cDNA. AOA2 cells exhibited constitutive oxidative DNA damage and enhanced chromosomal instability in response to H2O2. Rejoining of H2O2-induced DNA double-strand breaks (DSBs) was significantly reduced in AOA2 cells compared to controls, and there was no evidence for a defect in DNA single-strand break repair. This defect in DSB repair was corrected by full-length SETX cDNA. These results provide evidence that an additional member of the autosomal recessive AOA is also characterized by a defective response to DNA damage, which may contribute to the neurodegeneration seen in this syndrome.

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 ATM-dependent pathways of chromatin remodelling and oxidative DNA damage responses

2017 ◽  
Vol 372 (1731) ◽  
pp. 20160283 ◽  
Author(s):  
N. Daniel Berger ◽  
Fintan K. T. Stanley ◽  
Shaun Moore ◽  
Aaron A. Goodarzi
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Strand Break ◽  
Chromatin Remodelling ◽  
Double Strand Breaks ◽  
Biochemical Network ◽  
Regulatory Function ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
The Impact

Ataxia-telangiectasia mutated (ATM) is a serine/threonine protein kinase with a master regulatory function in the DNA damage response. In this role, ATM commands a complex biochemical network that signals the presence of oxidative DNA damage, including the dangerous DNA double-strand break, and facilitates subsequent repair. Here, we review the current state of knowledge regarding ATM-dependent chromatin remodelling and epigenomic alterations that are required to maintain genomic integrity in the presence of DNA double-strand breaks and/or oxidative stress. We will focus particularly on the roles of ATM in adjusting nucleosome spacing at sites of unresolved DNA double-strand breaks within complex chromatin environments, and the impact of ATM on preserving the health of cells within the mammalian central nervous system. This article is part of the themed issue ‘Chromatin modifiers and remodellers in DNA repair and signalling’.

End-damage-specific proteins facilitate recruitment or stability of X-ray cross-complementing protein 1 at the sites of DNA single-strand break repair

FEBS Journal ◽  
2005 ◽  
Vol 272 (22) ◽  
pp. 5753-5763 ◽  
Author(s):  
Jason L. Parsons ◽  
Irina I. Dianova ◽  
Emma Boswell ◽  
Michael Weinfeld ◽  
Grigory L. Dianov
Keyword(s):  
Strand Break ◽  
Single Strand ◽  
Single Strand Break ◽  
X Ray ◽  
Single Strand Break Repair ◽  
Specific Proteins ◽  
Break Repair

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.

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