Abstract P487: Impact Of Oxidative Dna Damage On Heart Health

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Kaitlin Lowran ◽  
Colin Wu ◽  
Ingrid Petersen
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Cardiovascular Diseases ◽  
Oxidative Dna Damage ◽  
Contractile Function ◽  
Heart Health ◽  
Dna Breaks ◽  
Human Cardiomyocytes ◽  
Double Stranded Dna

The accumulation of DNA damage in human cardiomyocytes causes apoptosis which can lead to heart failure or other cardiovascular diseases. Although the effects of oxidative stress on heart health and on the DNA Damage Response network are well-known, the two fields have evolved as separate areas of research. The precise impact of oxidative DNA damage on cardiomyocyte contractile function still remains poorly understood. The human FANCJ helicase participates in multiple DNA repair pathways, including interstrand crosslink repair and double-stranded break repair. We have shown previously that FANCJ targets and unfolds 8-oxoguanine modified DNA secondary structures that arise from oxidative damage. We predict that human cardiomyocytes expressing mutations of FANCJ would be more susceptible to oxidative DNA damage and will negatively influence their contractile motion. To test this, hiPSC-CMs were treated with hydrogen peroxide, camptothecin, or bleomycin to induce different forms of DNA damage. The relative abundance of single-stranded DNA breaks and double-stranded DNA breaks were determined by modified comet assays, while contractile function was monitored using video-based detection methods. Cells that overexpress FANCJ protein were able to overcome the chemical stress from hydrogen peroxide. On the contrary, cells that produce a FANCJ K141/K142AA variant, which was previously characterized in the lab, resulted in a hypersensitivity to double-stranded DNA breaks. Based on this evidence, FANCJ plays a vital role in alleviating the effects of oxidative stress. Our long-term goal is to use the established methods to develop functional assays that characterize the cardiovascular risks of other FANCJ variants. These assays can be used to develop screening methods to identify patients who may be predisposed to FANCJ-associated cardiovascular diseases.

scholarly journals Inhibition of the activin receptor improves cardiac remodelling in the ercc1 mouse model of accelerated ageing

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N Clavere ◽  
K Patel ◽  
E Kevei ◽  
S.Y Boateng
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Signalling Pathway ◽  
Heart Weight ◽  
Accelerated Ageing ◽  
Dna Breaks ◽  
Activin Receptor ◽  
Beneficial Effects ◽  
Cardiac Phenotype ◽  
Double Stranded Dna

Abstract Introduction In the heart, ageing is associated with pathological remodelling due to an increase of DNA damage, oxidative stress and fibrosis that impairs function, often leading to heart failure. Ageing is also associated with activation of the activin signalling pathway which contributes to cardiac dysfunction. Previous studies have shown that inhibition of the activin signalling pathway preserves cardiac function during aging. However, the beneficial effects of this inhibition in cardiac disorders such as accelerated ageing remain unknown. Purpose We hypothesized that inhibition of the activin receptor would be beneficial for the pathological cardiac phenotype of the Ercc1Δ/− mouse model of accelerated ageing. We aimed to determine the cardiac phenotype of the Ercc1 mouse, and how inhibition of activin signalling affects cardiac remodelling using immunological and biochemical analysis. Methods Using immunohistochemical staining, we investigated the cardiac phenotype in 16 week old Ercc1Δ/− progeric and Ercc1+/+ wildtype mice (n=4–6) with or without soluble activin receptor injections from the week 7 (sActRIIB, 10mg/kg). The Ercc1Δ/− mouse displays a deficiency in DNA repair, leading to an accelerated ageing phenotype. Experimentally, injections of the myostatin /activin antagonist called the soluble ActRIIB receptor trap (sActRIIB) can be used to pharmacologically target the activin signalling pathway. Results In Ercc1Δ/− mice at 16 weeks there was a 50% decrease in the heart weight in comparison to Ercc1+/+ wildtype mice (175±13 vs 85±4), (p<0.001). Activin inhibition did not have any effect on the heart weight. To determine the extent of DNA damage, cardiac tissue was stained for γH2Ax. γH2Ax accumulates at double stranded DNA breaks where histone 2A becomes phosphorylated. Ercc1Δ/− mice displayed a 20% increase in double stranded DNA breaks in comparison to the Ercc1+/+ wildtype (0.6±0.5 vs 22.5±2.5 vs 15.8±0.7), (p<0.01). Activin inhibition led to a significant 5% decrease (p<0.05). Oxidative stress was determined by dihydroethidium staining. Ercc1Δ/− mice showed a 30% increase in oxidative stress (33.33±3 vs 49.98±3 vs 36.19±3), (p<0.05). Activin inhibition reversed this increase of oxidative stress in Ercc1Δ/− mice (p<0.05). Finally, cardiac fibrosis was assessed using picrosirius red staining. No differences were observed between the Ercc1Δ/− progerics and Ercc1+/+ wildtype mice, while activin inhibition led to a 50% decrease (4.9±0.3 vs 7.7±1.3 vs 2.9±0.1), (p<0.01). Interestingly, Ercc1Δ/− mice display thicker cardiac interstitial collagen I (1.3±0.01 vs 1.4±0.05 vs 1.3±0.01), (p<0.05). Activin inhibition also reversed this increased interstitial collagen (p<0.05). Conclusion Inhibition of activin receptor signalling brings beneficial effects to the Ercc1Δ/− cardiac phenotype by attenuating oxidative stress, DNA damage and fibrosis. Funding Acknowledgement Type of funding source: None

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.

Antioxidative Effect of Rhus javanica Linne Extract Against Hydrogen Peroxide or Menadione Induced Oxidative Stress and DNA Damage in HepG2Cells

2004 ◽  
Vol 9 (2) ◽  
pp. 150-155 ◽  
Author(s):  
Chi-Sung Chun ◽  
Ji-Hyun Kim ◽  
Hyun-Ae Lim ◽  
Ho-Yong Sohn ◽  
Kun-Ho Son ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Antioxidative Effect

scholarly journals The Use of Coenzyme Q10 in Cardiovascular Diseases

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 755
Author(s):  
Yoana Rabanal-Ruiz ◽  
Emilio Llanos-González ◽  
Francisco J. Alcain
Keyword(s):  
Oxidative Stress ◽  
Cardiovascular Diseases ◽  
Endothelial Dysfunction ◽  
Vascular System ◽  
Contractile Function ◽  
Artery Bypass ◽  
Bypass Graft ◽  
No Bioavailability ◽  
Coq10 Supplementation ◽  
Endogenous Antioxidant

CoQ10 is an endogenous antioxidant produced in all cells that plays an essential role in energy metabolism and antioxidant protection. CoQ10 distribution is not uniform among different organs, and the highest concentration is observed in the heart, though its levels decrease with age. Advanced age is the major risk factor for cardiovascular disease and endothelial dysfunction triggered by oxidative stress that impairs mitochondrial bioenergetic and reduces NO bioavailability, thus affecting vasodilatation. The rationale of the use of CoQ10 in cardiovascular diseases is that the loss of contractile function due to an energy depletion status in the mitochondria and reduced levels of NO for vasodilatation has been associated with low endogenous CoQ10 levels. Clinical evidence shows that CoQ10 supplementation for prolonged periods is safe, well-tolerated and significantly increases the concentration of CoQ10 in plasma up to 3–5 µg/mL. CoQ10 supplementation reduces oxidative stress and mortality from cardiovascular causes and improves clinical outcome in patients undergoing coronary artery bypass graft surgery, prevents the accumulation of oxLDL in arteries, decreases vascular stiffness and hypertension, improves endothelial dysfunction by reducing the source of ROS in the vascular system and increases the NO levels for vasodilation.

scholarly journals Escherichia coli MutM Suppresses Illegitimate Recombination Induced by Oxidative Stress

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 439-446 ◽  
Author(s):  
Masaaki Onda ◽  
Katsuhiro Hanada ◽  
Hirokazu Kawachi ◽  
Hideo Ikeda
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Double Strand Breaks ◽  
Illegitimate Recombination ◽  
Recombination Analysis ◽  
Wild Type ◽  
Strand Breaks ◽  
In The Wild

Abstract DNA damage by oxidative stress is one of the causes of mutagenesis. However, whether or not DNA damage induces illegitimate recombination has not been determined. To study the effect of oxidative stress on illegitimate recombination, we examined the frequency of λbio transducing phage in the presence of hydrogen peroxide and found that this reagent enhances illegitimate recombination. To clarify the types of illegitimate recombination, we examined the effect of mutations in mutM and related genes on the process. The frequency of λbio transducing phage was 5- to 12-fold higher in the mutM mutant than in the wild type, while the frequency in the mutY and mutT mutants was comparable to that of the wild type. Because 7,8-dihydro-8-oxoguanine (8-oxoG) and formamido pyrimidine (Fapy) lesions can be removed from DNA by MutM protein, these lesions are thought to induce illegitimate recombination. Analysis of recombination junctions showed that the recombination at Hotspot I accounts for 22 or 4% of total λbio transducing phages in the wild type or in the mutM mutant, respectively. The preferential increase of recombination at nonhotspot sites with hydrogen peroxide in the mutM mutant was discussed on the basis of a new model, in which 8-oxoG and/or Fapy residues may introduce double-strand breaks into DNA.

scholarly journals DHX9-dependent recruitment of BRCA1 to RNA promotes DNA end resection in homologous recombination

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Prasun Chakraborty ◽  
Kevin Hiom
Keyword(s):  
Dna Damage ◽  
Homologous Recombination ◽  
Rna Polymerase Ii ◽  
Critical Role ◽  
Dna Breaks ◽  
Double Stranded Dna ◽  
Recombination Repair ◽  
Dna End Resection ◽  
End Resection ◽  
Rna Polymerase Ii Transcription

AbstractDouble stranded DNA Breaks (DSB) that occur in highly transcribed regions of the genome are preferentially repaired by homologous recombination repair (HR). However, the mechanisms that link transcription with HR are unknown. Here we identify a critical role for DHX9, a RNA helicase involved in the processing of pre-mRNA during transcription, in the initiation of HR. Cells that are deficient in DHX9 are impaired in the recruitment of RPA and RAD51 to sites of DNA damage and fail to repair DSB by HR. Consequently, these cells are hypersensitive to treatment with agents such as camptothecin and Olaparib that block transcription and generate DSB that specifically require HR for their repair. We show that DHX9 plays a critical role in HR by promoting the recruitment of BRCA1 to RNA as part of the RNA Polymerase II transcription complex, where it facilitates the resection of DSB. Moreover, defects in DHX9 also lead to impaired ATR-mediated damage signalling and an inability to restart DNA replication at camptothecin-induced DSB. Together, our data reveal a previously unknown role for DHX9 in the DNA Damage Response that provides a critical link between RNA, RNA Pol II and the repair of DNA damage by homologous recombination.

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 Labile iron pool correlates with iron content in the nucleus and the formation of oxidative DNA damage in mouse lymphoma L5178Y cell lines.

2003 ◽  
Vol 50 (1) ◽  
pp. 211-215 ◽  
Author(s):  
Marcin Kruszewski ◽  
Teresa Iwaneńko
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Cell Lines ◽  
Oxidative Dna Damage ◽  
Transition Metal Ions ◽  
Dna Lesions ◽  
Labile Iron Pool ◽  
Labile Iron ◽  
Iron Pool ◽  
Mouse Lymphoma

Labile iron pool (LIP) constitutes a crossroad of metabolic pathways of iron-containing compounds and is midway between the cellular need for iron, its uptake and storage. In this study we investigated oxidative DNA damage in relation to the labile iron pool in a pair of mouse lymphoma L5178Y (LY) sublines (LY-R and LY-S) differing in sensitivity to hydrogen peroxide. The LY-R cells, which are hydrogen peroxide-sensitive, contain 3 times more labile iron than the hydrogen peroxide-resistant LY-S cells. Using the comet assay, we compared total DNA breakage in the studied cell lines treated with hydrogen peroxide (25 microM for 30 min at 4 degrees C). More DNA damage was found in LY-R cells than in LY-S cells. We also compared the levels of DNA lesions sensitive to specific DNA repair enzymes in both cell lines treated with H(2)O(2). The levels of endonuclease III-sensitive sites and Fapy-DNA glycosylase-sensitive sites were found to be higher in LY-R cells than in LY-S cells. Our data suggest that the sensitivity of LY-R cells to H(2)O(2) is partially caused by the higher yield of oxidative DNA damage, as compared to that in LY-S cells. The critical factor appears to be the availability of transition metal ions that take part in the OH radical-generating Fenton reaction (very likely in the form of LIP).

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.

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