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Sample records for dna damage oxidative

  1. Oxidative DNA damage & repair: An introduction.

    Science.gov (United States)

    Cadet, Jean; Davies, Kelvin J A

    2017-06-01

    This introductory article should be viewed as a prologue to the Free Radical Biology & Medicine Special Issue devoted to the important topic of Oxidatively Damaged DNA and its Repair. This special issue is dedicated to Professor Tomas Lindahl, co-winner of the 2015 Nobel Prize in Chemistry for his seminal discoveries in the area repair of oxidatively damaged DNA. In the past several years it has become abundantly clear that DNA oxidation is a major consequence of life in an oxygen-rich environment. Concomitantly, survival in the presence of oxygen, with the constant threat of deleterious DNA mutations and deletions, has largely been made possible through the evolution of a vast array of DNA repair enzymes. The articles in this Oxidatively Damaged DNA & Repair special issue detail the reactions by which intracellular DNA is oxidatively damaged, and the enzymatic reactions and pathways by which living organisms survive such assaults by repair processes. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Aging and oxidatively damaged nuclear DNA in animal organs

    DEFF Research Database (Denmark)

    Møller, Peter; Løhr, Mille; Folkmann, Janne K

    2010-01-01

    Oxidative stress is considered to contribute to aging and is associated with the generation of oxidatively damaged DNA, including 8-oxo-7,8-dihydroguanine. We have identified 69 studies that have measured the level of oxidatively damaged DNA in organs of animals at various ages. In general, organs...... with limited cell proliferation, i.e., liver, kidney, brain, heart, pancreas, and muscle, tended to show accumulation of DNA damage with age, whereas organs with highly proliferating cells, such as intestine, spleen, and testis, showed more equivocal or no effect of age. A restricted analysis of studies...... evidence for aging-associated accumulation of oxidatively damaged DNA in organs with limited cell proliferation....

  3. Oxidative DNA damage and oxidative stress in lead-exposed workers.

    Science.gov (United States)

    Dobrakowski, M; Pawlas, N; Kasperczyk, A; Kozłowska, A; Olewińska, E; Machoń-Grecka, A; Kasperczyk, S

    2017-07-01

    There are many discrepancies among the results of studies on the genotoxicity of lead. The aim of the study was to explore lead-induced DNA damage, including oxidative damage, in relation to oxidative stress intensity parameters and the antioxidant defense system in human leukocytes. The study population consisted of 100 male workers exposed to lead. According to the blood lead (PbB) levels, they were divided into the following three subgroups: a group with PbB of 20-35 μg/dL (low exposure to lead (LE) group), a group with a PbB of 35-50 µg/dL (medium exposure to lead (ME) group), and a group with a PbB of >50 μg/dL (high exposure to lead (HE) group). The control group consisted of 42 healthy males environmentally exposed to lead (PbB lead exposure induces DNA damage, including oxidative damage, in human leukocytes. The increase in DNA damage was accompanied by an elevated intensity of oxidative stress.

  4. Measurement of oxidative damage to DNA in nanomaterial exposed cells and animals

    DEFF Research Database (Denmark)

    Møller, Peter; Jensen, Ditte Marie; Christophersen, Daniel Vest

    2015-01-01

    -reactivity with other molecules in cells. This review provides an overview of efforts to reliably detect oxidatively damaged DNA and a critical assessment of the published studies on DNA damage levels. Animal studies with high baseline levels of oxidatively damaged DNA are more likely to show positive associations...... of oxidatively damaged DNA in lung tissue. Oral exposure to nanosized carbon black, TiO2 , carbon nanotubes and ZnO is associated with elevated levels of oxidatively damaged DNA in tissues. These observations are supported by cell culture studies showing concentration-dependent associations between ENM exposure...... and oxidatively damaged DNA measured by the comet assay. Cell culture studies show relatively high variation in the ability of ENMs to oxidatively damage DNA; hence, it is currently impossible to group ENMs according to their DNA damaging potential. Environ. Mol. Mutagen., 2014. © 2014 Wiley Periodicals, Inc....

  5. Increased oxidative DNA damage in mononuclear leukocytes in vitiligo

    Energy Technology Data Exchange (ETDEWEB)

    Giovannelli, Lisa [Department of Preclinical and Clinical Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence (Italy)]. E-mail: lisag@pharm.unifi.it; Bellandi, Serena [Department of Dermatological Sciences, University of Florence, Viale Pieraccini 6, 50139 Florence (Italy); Pitozzi, Vanessa [Department of Preclinical and Clinical Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence (Italy); Fabbri, Paolo [Department of Dermatological Sciences, University of Florence, Viale Pieraccini 6, 50139 Florence (Italy); Dolara, Piero [Department of Preclinical and Clinical Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence (Italy); Moretti, Silvia [Department of Dermatological Sciences, University of Florence, Viale Pieraccini 6, 50139 Florence (Italy)

    2004-11-22

    Vitiligo is an acquired pigmentary disorder of the skin of unknown aetiology. The autocytotoxic hypothesis suggests that melanocyte impairment could be related to increased oxidative stress. Evidences have been reported that in vitiligo oxidative stress might also be present systemically. We used the comet assay (single cell alkaline gel electrophoresis) to evaluate DNA strand breaks and DNA base oxidation, measured as formamidopyrimidine DNA glycosylase (FPG)-sensitive sites, in peripheral blood cells from patients with active vitiligo and healthy controls. The basal level of oxidative DNA damage in mononuclear leukocytes was increased in vitiligo compared to normal subjects, whereas DNA strand breaks (SBs) were not changed. This alteration was not accompanied by a different capability to respond to in vitro oxidative challenge. No differences in the basal levels of DNA damage in polymorphonuclear leukocytes were found between patients and healthy subjects. Thus, this study supports the hypothesis that in vitiligo a systemic oxidative stress exists, and demonstrates for the first time the presence of oxidative alterations at the nuclear level. The increase in oxidative DNA damage shown in the mononuclear component of peripheral blood leukocytes from vitiligo patients was not particularly severe. However, these findings support an adjuvant role of antioxidant treatment in vitiligo.

  6. Increased oxidative DNA damage in mononuclear leukocytes in vitiligo

    International Nuclear Information System (INIS)

    Giovannelli, Lisa; Bellandi, Serena; Pitozzi, Vanessa; Fabbri, Paolo; Dolara, Piero; Moretti, Silvia

    2004-01-01

    Vitiligo is an acquired pigmentary disorder of the skin of unknown aetiology. The autocytotoxic hypothesis suggests that melanocyte impairment could be related to increased oxidative stress. Evidences have been reported that in vitiligo oxidative stress might also be present systemically. We used the comet assay (single cell alkaline gel electrophoresis) to evaluate DNA strand breaks and DNA base oxidation, measured as formamidopyrimidine DNA glycosylase (FPG)-sensitive sites, in peripheral blood cells from patients with active vitiligo and healthy controls. The basal level of oxidative DNA damage in mononuclear leukocytes was increased in vitiligo compared to normal subjects, whereas DNA strand breaks (SBs) were not changed. This alteration was not accompanied by a different capability to respond to in vitro oxidative challenge. No differences in the basal levels of DNA damage in polymorphonuclear leukocytes were found between patients and healthy subjects. Thus, this study supports the hypothesis that in vitiligo a systemic oxidative stress exists, and demonstrates for the first time the presence of oxidative alterations at the nuclear level. The increase in oxidative DNA damage shown in the mononuclear component of peripheral blood leukocytes from vitiligo patients was not particularly severe. However, these findings support an adjuvant role of antioxidant treatment in vitiligo

  7. Oxidative DNA damage during sleep periods among nightshift workers.

    Science.gov (United States)

    Bhatti, Parveen; Mirick, Dana K; Randolph, Timothy W; Gong, Jicheng; Buchanan, Diana Taibi; Zhang, Junfeng Jim; Davis, Scott

    2016-08-01

    Oxidative DNA damage may be increased among nightshift workers because of suppression of melatonin, a cellular antioxidant, and/or inflammation related to sleep disruption. However, oxidative DNA damage has received limited attention in previous studies of nightshift work. From two previous cross-sectional studies, urine samples collected during a night sleep period for 217 dayshift workers and during day and night sleep (on their first day off) periods for 223 nightshift workers were assayed for 8-hydroxydeoxyguanosine (8-OH-dG), a marker of oxidative DNA damage, using high-performance liquid chromatography with electrochemical detection. Urinary measures of 6-sulfatoxymelatonin (aMT6s), a marker of circulating melatonin levels, and actigraphy-based sleep quality data were also available. Nightshift workers during their day sleep periods excreted 83% (p=0.2) and 77% (p=0.03) of the 8-OH-dG that dayshift workers and they themselves, respectively, excreted during their night sleep periods. Among nightshift workers, higher aMT6s levels were associated with higher urinary 8-OH-dG levels, and an inverse U-shaped trend was observed between 8-OH-dG levels and sleep efficiency and sleep duration. Reduced excretion of 8-OH-dG among nightshift workers during day sleep may reflect reduced functioning of DNA repair machinery, which could potentially lead to increased cellular levels of oxidative DNA damage. Melatonin disruption among nightshift workers may be responsible for the observed effect, as melatonin is known to enhance repair of oxidative DNA damage. Quality of sleep may similarly impact DNA repair. Cellular levels of DNA damage will need to be evaluated in future studies to help interpret these findings. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  8. Preterm newborns show slower repair of oxidative damage and paternal smoking associated DNA damage.

    Science.gov (United States)

    Vande Loock, Kim; Ciardelli, Roberta; Decordier, Ilse; Plas, Gina; Haumont, Dominique; Kirsch-Volders, Micheline

    2012-09-01

    Newborns have to cope with hypoxia during delivery and a sudden increase in oxygen at birth. Oxygen will partly be released as reactive oxygen species having the potential to cause damage to DNA and proteins. In utero, increase of most (non)-enzymatic antioxidants occurs during last weeks of gestation, making preterm neonates probably more sensitive to oxidative stress. Moreover, it has been hypothesized that oxidative stress might be the common etiological factor for certain neonatal diseases in preterm infants. The aim of this study was to assess background DNA damage; in vitro H(2)O(2) induced oxidative DNA damage and repair capacity (residual DNA damage) in peripheral blood mononucleated cells from 25 preterm newborns and their mothers. In addition, demographic data were taken into account and repair capacity of preterm was compared with full-term newborns. Multivariate linear regression analysis revealed that preterm infants from smoking fathers have higher background DNA damage levels than those from non-smoking fathers, emphasizing the risk of paternal smoking behaviour for the progeny. Significantly higher residual DNA damage found after 15-min repair in preterm children compared to their mothers and higher residual DNA damage after 2 h compared to full-term newborns suggest a slower DNA repair capacity in preterm children. In comparison with preterm infants born by caesarean delivery, preterm infants born by vaginal delivery do repair more slowly the in vitro induced oxidative DNA damage. Final impact of passive smoking and of the slower DNA repair activity of preterm infants need to be confirmed in a larger study population combining transgenerational genetic and/or epigenetic effects, antioxidant levels, genotypes, repair enzyme efficiency/levels and infant morbidity.

  9. DNA Mismatch Repair and Oxidative DNA Damage: Implications for Cancer Biology and Treatment

    International Nuclear Information System (INIS)

    Bridge, Gemma; Rashid, Sukaina; Martin, Sarah A.

    2014-01-01

    Many components of the cell, including lipids, proteins and both nuclear and mitochondrial DNA, are vulnerable to deleterious modifications caused by reactive oxygen species. If not repaired, oxidative DNA damage can lead to disease-causing mutations, such as in cancer. Base excision repair and nucleotide excision repair are the two DNA repair pathways believed to orchestrate the removal of oxidative lesions. However, recent findings suggest that the mismatch repair pathway may also be important for the response to oxidative DNA damage. This is particularly relevant in cancer where mismatch repair genes are frequently mutated or epigenetically silenced. In this review we explore how the regulation of oxidative DNA damage by mismatch repair proteins may impact on carcinogenesis. We discuss recent studies that identify potential new treatments for mismatch repair deficient tumours, which exploit this non-canonical role of mismatch repair using synthetic lethal targeting

  10. DNA Mismatch Repair and Oxidative DNA Damage: Implications for Cancer Biology and Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Bridge, Gemma; Rashid, Sukaina; Martin, Sarah A., E-mail: sarah.martin@qmul.ac.uk [Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ (United Kingdom)

    2014-08-05

    Many components of the cell, including lipids, proteins and both nuclear and mitochondrial DNA, are vulnerable to deleterious modifications caused by reactive oxygen species. If not repaired, oxidative DNA damage can lead to disease-causing mutations, such as in cancer. Base excision repair and nucleotide excision repair are the two DNA repair pathways believed to orchestrate the removal of oxidative lesions. However, recent findings suggest that the mismatch repair pathway may also be important for the response to oxidative DNA damage. This is particularly relevant in cancer where mismatch repair genes are frequently mutated or epigenetically silenced. In this review we explore how the regulation of oxidative DNA damage by mismatch repair proteins may impact on carcinogenesis. We discuss recent studies that identify potential new treatments for mismatch repair deficient tumours, which exploit this non-canonical role of mismatch repair using synthetic lethal targeting.

  11. Lymphocyte DNA damage and oxidative stress in patients with iron deficiency anemia.

    Science.gov (United States)

    Aslan, Mehmet; Horoz, Mehmet; Kocyigit, Abdurrahim; Ozgonül, Saadet; Celik, Hakim; Celik, Metin; Erel, Ozcan

    2006-10-10

    Oxidant stress has been shown to play an important role in the pathogenesis of iron deficiency anemia. The aim of this study was to investigate the association between lymphocyte DNA damage, total antioxidant capacity and the degree of anemia in patients with iron deficiency anemia. Twenty-two female with iron deficiency anemia and 22 healthy females were enrolled in the study. Peripheral DNA damage was assessed using alkaline comet assay and plasma total antioxidant capacity was determined using an automated measurement method. Lymphocyte DNA damage of patients with iron deficiency anemia was significantly higher than controls (ptotal antioxidant capacity was significantly lower (ptotal antioxidant capacity and hemoglobin levels (r=0.706, ptotal antioxidant capacity and hemoglobin levels were negatively correlated with DNA damage (r=-0.330, p<0.05 and r=-0.323, p<0.05, respectively). In conclusion, both oxidative stress and DNA damage are increased in IDA patients. Increased oxidative stress seems as an important factor that inducing DNA damage in those IDA patients. The relationships of oxidative stress and DNA damage with the severity of anemia suggest that both oxidative stress and DNA damage may, in part, have a role in the pathogenesis of IDA.

  12. Oxidative DNA damage causes mitochondrial genomic instability in Saccharomyces cerevisiae.

    Science.gov (United States)

    Doudican, Nicole A; Song, Binwei; Shadel, Gerald S; Doetsch, Paul W

    2005-06-01

    Mitochondria contain their own genome, the integrity of which is required for normal cellular energy metabolism. Reactive oxygen species (ROS) produced by normal mitochondrial respiration can damage cellular macromolecules, including mitochondrial DNA (mtDNA), and have been implicated in degenerative diseases, cancer, and aging. We developed strategies to elevate mitochondrial oxidative stress by exposure to antimycin and H(2)O(2) or utilizing mutants lacking mitochondrial superoxide dismutase (sod2Delta). Experiments were conducted with strains compromised in mitochondrial base excision repair (ntg1Delta) and oxidative damage resistance (pif1Delta) in order to delineate the relationship between these pathways. We observed enhanced ROS production, resulting in a direct increase in oxidative mtDNA damage and mutagenesis. Repair-deficient mutants exposed to oxidative stress conditions exhibited profound genomic instability. Elimination of Ntg1p and Pif1p resulted in a synergistic corruption of respiratory competency upon exposure to antimycin and H(2)O(2). Mitochondrial genomic integrity was substantially compromised in ntg1Delta pif1Delta sod2Delta strains, since these cells exhibit a total loss of mtDNA. A stable respiration-defective strain, possessing a normal complement of mtDNA damage resistance pathways, exhibited a complete loss of mtDNA upon exposure to antimycin and H(2)O(2). This loss was preventable by Sod2p overexpression. These results provide direct evidence that oxidative mtDNA damage can be a major contributor to mitochondrial genomic instability and demonstrate cooperation of Ntg1p and Pif1p to resist the introduction of lesions into the mitochondrial genome.

  13. Oxidatively generated DNA/RNA damage in psychological stress states

    DEFF Research Database (Denmark)

    Jørgensen, Anders

    2013-01-01

    age-related somatic disorders. The overall aim of the PhD project was to investigate the relation between psychopathology, psychological stress, stress hormone secretion and oxidatively generated DNA and RNA damage, as measured by the urinary excretion of markers of whole-body DNA/RNA oxidation (8...... between the 24 h urinary cortisol excretion and the excretion of 8-oxodG/8-oxoGuo, determined in the same samples. Collectively, the studies could not confirm an association between psychological stress and oxidative stress on nucleic acids. Systemic oxidatively generated DNA/RNA damage was increased......Both non-pathological psychological stress states and mental disorders are associated with molecular, cellular and epidemiological signs of accelerated aging. Oxidative stress on nucleic acids is a critical component of cellular and organismal aging, and a suggested pathogenic mechanism in several...

  14. Thyroid hormone-induced oxidative damage on lipids, glutathione and DNA in the mouse heart.

    Science.gov (United States)

    Gredilla, R; Barja, G; López-Torres, M

    2001-10-01

    Oxygen radicals of mitochondrial origin are involved in oxidative damage. In order to analyze the possible relationship between metabolic rate, oxidative stress and oxidative damage, OF1 female mice were rendered hyper- and hypothyroid by chronic administration of 0.0012% L-thyroxine (T4) and 0.05% 6-n-propyl-2-thiouracil (PTU), respectively, in their drinking water for 5 weeks. Hyperthyroidism significantly increased the sensitivity to lipid peroxidation in the heart, although the endogenous levels of lipid peroxidation were not altered. Thyroid hormone-induced oxidative stress also resulted in higher levels of GSSG and GSSG/GSH ratio. Oxidative damage to mitochondrial DNA was greater than that to genomic DNA. Hyperthyroidism decreased oxidative damage to genomic DNA. Hypothyroidism did not modify oxidative damage in the lipid fraction but significantly decreased GSSG and GSSG/GSH ratio and oxidative damage to mitochondrial DNA. These results indicate that thyroid hormones modulate oxidative damage to lipids and DNA, and cellular redox potential in the mouse heart. A higher oxidative stress in the hyperthyroid group is presumably neutralized in the case of nuclear DNA by an increase in repair activity, thus protecting this key molecule. Treatment with PTU, a thyroid hormone inhibitor, reduced oxidative damage in the different cell compartments.

  15. Detection of DNA damage by using hairpin molecular beacon probes and graphene oxide.

    Science.gov (United States)

    Zhou, Jie; Lu, Qian; Tong, Ying; Wei, Wei; Liu, Songqin

    2012-09-15

    A hairpin molecular beacon tagged with carboxyfluorescein in combination with graphene oxide as a quencher reagent was used to detect the DNA damage by chemical reagents. The fluorescence of molecular beacon was quenched sharply by graphene oxide; while in the presence of its complementary DNA the quenching efficiency decreased because their hybridization prevented the strong adsorbability of molecular beacon on graphene oxide. If the complementary DNA was damaged by a chemical reagent and could not form intact duplex structure with molecular beacon, more molecular beacon would adsorb on graphene oxide increasing the quenching efficiency. Thus, damaged DNA could be detected based on different quenching efficiencies afforded by damaged and intact complementary DNA. The damage effects of chlorpyrifos-methyl and three metabolites of styrene such as mandelieaeids, phenylglyoxylieaeids and epoxystyrene on DNA were studied as models. The method for detection of DNA damage was reliable, rapid and simple compared to the biological methods. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. The Inhibition Effect of Cell DNA Oxidative Damage and LDL Oxidation by Bovine Colostrums

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    Chih-Wei Chen

    2016-10-01

    Full Text Available In the present study, we investigated the effect of bovine colostrums on inhibition of DNA oxidative damage and low density lipoprotein (LDL oxidation in vitro. Results showed that whey and skimmed milk exhibited not only higher inhibitory activities of oxidative damage of deoxyribose but also an inhibitory effect on the breakdown of supercoiled DNA into open circular DNA and linear DNA. The quantities of 8-OH-2′-dG formed under whey, caseins and skimmed milk treatment were 0.24, 0.24 and 1.24 μg/mL, respectively. The quantity of malondialdehyde formed through LDL oxidation induced by copprous ion was significantly decreased as colostrums protein solutions were added, in which whey and caseins led to a more significant decrease than skimmed milk. The formation of conjugated dienes could be inhibited by treatment with colostrums protein solutions. Whey exhibited the longest lag time of conjugated dienes formation among the colostrums proteins. The lag time of the whey was 2.33 times that of the control. From the results of foregoing, the bovine colostrums protein has potential value in the inhibition of DNA oxidation damage and LDL oxidation.

  17. Inflammation, oxidative DNA damage, and carcinogenesis

    International Nuclear Information System (INIS)

    Lewis, J.G.; Adams, D.O.

    1987-01-01

    Inflammation has long been associated with carcinogenesis, especially in the promotion phase. The mechanism of action of the potent inflammatory agent and skin promoter 12-tetradecanoyl phorbol-13-acetate (TPA) is unknown. It is though that TPA selectively enhances the growth of initiated cells, and during this process, initiated cells progress to the preneoplastic state and eventually to the malignant phenotype. The authors and others have proposed that TPA may work, in part, by inciting inflammation and stimulating inflammatory cells to release powerful oxidants which then induce DNA damage in epidermal cells. Macrophages cocultured with target cells and TPA induce oxidized thymine bases in the target cells. This process is inhibited by both catalase and inhibitors of lipoxygenases, suggesting the involvement of both H 2 O 2 and oxidized lipid products. In vivo studies demonstrated that SENCAR mice, which are sensitive to promotion by TPA, have a more intense inflammatory reaction in skin that C57LB/6 mice, which are resistant to promotion by TPA. In addition, macrophages from SENCAR mice release more H 2 O 2 and metabolites of AA, and induce more oxidative DNA damage in cocultured cells than macrophages from C57LB/6 mice. These data support the hypothesis that inflammation and the release of genotoxic oxidants may be one mechanism whereby initiated cells receive further genetic insults. They also further complicate risk assessment by suggesting that some environmental agents may work indirectly by subverting host systems to induce damage rather than maintaining homeostasis

  18. Experimental study of oxidative DNA damage

    DEFF Research Database (Denmark)

    Loft, Steffen; Deng, Xin-Sheng; Tuo, Jingsheng

    1998-01-01

    Animal experiments allow the study of oxidative DNA damage in target organs and the elucidation of dose-response relationships of carcinogenic and other harmful chemicals and conditions as well as the study of interactions of several factors. So far the effects of more than 50 different chemical ...

  19. Oxidative damage of DNA in subjects occupationally exposed to lead.

    Science.gov (United States)

    Pawlas, Natalia; Olewińska, Elżbieta; Markiewicz-Górka, Iwona; Kozłowska, Agnieszka; Januszewska, Lidia; Lundh, Thomas; Januszewska, Ewa; Pawlas, Krystyna

    2017-09-01

    Exposure to lead (Pb) in environmental and occupational settings continues to be a serious public health problem and may pose an elevated risk of genetic damage. The aim of this study was to assess the level of oxidative stress and DNA damage in subjects occupationally exposed to lead. We studied a population of 78 male workers exposed to lead in a lead and zinc smelter and battery recycling plant and 38 men from a control group. Blood lead levels were detected by graphite furnace atomic absorption spectrophotometry and plasma lead levels by inductively coupled plasma-mass spectrometry. The following assays were performed to assess the DNA damage and oxidative stress: comet assay, determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG), lipid peroxidation and total antioxidant status (TAS). The mean concentration of lead in the blood of the exposed group was 392 ± 103 μg/L and was significantly higher than in the control group (30.3 ± 29.4 μg/L, p lead exposure [lead in blood, lead in plasma, zinc protoporphyrin (ZPP)] and urine concentration of 8-OHdG. The level of oxidative damage of DNA was positively correlated with the level of lipid peroxidation (TBARS) and negatively with total anti-oxidative status (TAS). Our study suggests that occupational exposure causes an increase in oxidative damage to DNA, even in subjects with relatively short length of service (average length of about 10 years). 8-OHdG concentration in the urine proved to be a sensitive and non-invasive marker of lead induced genotoxic damage.

  20. Endogenous melatonin and oxidatively damaged guanine in DNA

    DEFF Research Database (Denmark)

    Davanipour, Zoreh; Poulsen, Henrik E; Weimann, Allan

    2009-01-01

    overnight guanine DNA damage. 8-oxodG and 8-oxoGua were measured using a high-performance liquid chromatography-electrospray ionization tandem mass spectrometry assay. The mother, father, and oldest sampled daughter were used for these analyses. Comparisons between the mothers, fathers, and daughters were...... attack and increase the rate of repair of that damage. This paper reports the results of a study relating the level of overnight melatonin production to the overnight excretion of the two primary urinary metabolites of the repair of oxidatively damaged guanine in DNA. METHODS: Mother...

  1. Biomarkers of oxidative stress and DNA damage in agricultural workers: A pilot study

    International Nuclear Information System (INIS)

    Muniz, Juan F.; McCauley, Linda; Scherer, J.; Lasarev, M.; Koshy, M.; Kow, Y.W.; Nazar-Stewart, Valle; Kisby, G.E.

    2008-01-01

    Oxidative stress and DNA damage have been proposed as mechanisms linking pesticide exposure to health effects such as cancer and neurological diseases. A study of pesticide applicators and farmworkers was conducted to examine the relationship between organophosphate pesticide exposure and biomarkers of oxidative stress and DNA damage. Urine samples were analyzed for OP metabolites and 8-hydroxy-2'-deoxyguanosine (8-OH-dG). Lymphocytes were analyzed for oxidative DNA repair activity and DNA damage (Comet assay), and serum was analyzed for lipid peroxides (i.e., malondialdehyde, MDA). Cellular damage in agricultural workers was validated using lymphocyte cell cultures. Urinary OP metabolites were significantly higher in farmworkers and applicators (p < 0.001) when compared to controls. 8-OH-dG levels were 8.5 times and 2.3 times higher in farmworkers or applicators (respectively) than in controls. Serum MDA levels were 4.9 times and 24 times higher in farmworkers or applicators (respectively) than in controls. DNA damage (Comet assay) and oxidative DNA repair were significantly greater in lymphocytes from applicators and farmworkers when compared with controls. Markers of oxidative stress (i.e., increased reactive oxygen species and reduced glutathione levels) and DNA damage were also observed in lymphocyte cell cultures treated with an OP. The findings from these in vivo and in vitro studies indicate that organophosphate pesticides induce oxidative stress and DNA damage in agricultural workers. These biomarkers may be useful for increasing our understanding of the link between pesticides and a number of health effects

  2. Endogenous melatonin and oxidatively damaged guanine in DNA

    Directory of Open Access Journals (Sweden)

    Poulsen Henrik E

    2009-10-01

    Full Text Available Abstract Background A significant body of literature indicates that melatonin, a hormone primarily produced nocturnally by the pineal gland, is an important scavenger of hydroxyl radicals and other reactive oxygen species. Melatonin may also lower the rate of DNA base damage resulting from hydroxyl radical attack and increase the rate of repair of that damage. This paper reports the results of a study relating the level of overnight melatonin production to the overnight excretion of the two primary urinary metabolites of the repair of oxidatively damaged guanine in DNA. Methods Mother-father-daughter(s families (n = 55 were recruited and provided complete overnight urine samples. Total overnight creatinine-adjusted 6-sulphatoxymelatonin (aMT6s/Cr has been shown to be highly correlated with total overnight melatonin production. Urinary 8-oxo-7,8-dihydro-guanine (8-oxoGua results from the repair of DNA or RNA guanine via the nucleobase excision repair pathway, while urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG may possibly result from the repair of DNA guanine via the nucleotide excision repair pathway. Total overnight urinary levels of 8-oxodG and 8-oxoGua are therefore a measure of total overnight guanine DNA damage. 8-oxodG and 8-oxoGua were measured using a high-performance liquid chromatography-electrospray ionization tandem mass spectrometry assay. The mother, father, and oldest sampled daughter were used for these analyses. Comparisons between the mothers, fathers, and daughters were calculated for aMT6s/Cr, 8-oxodG, and 8-oxoGua. Regression analyses of 8-oxodG and 8-oxoGua on aMT6s/Cr were conducted for mothers, fathers, and daughters separately, adjusting for age and BMI (or weight. Results Among the mothers, age range 42-80, lower melatonin production (as measured by aMT6s/CR was associated with significantly higher levels of 8-oxodG (p Conclusion Low levels of endogenous melatonin production among older individuals may lead to

  3. Oxidative Stress, DNA Damage and DNA Repair in Female Patients with Diabetes Mellitus Type 2.

    Directory of Open Access Journals (Sweden)

    Annemarie Grindel

    Full Text Available Diabetes mellitus type 2 (T2DM is associated with oxidative stress which in turn can lead to DNA damage. The aim of the present study was to analyze oxidative stress, DNA damage and DNA repair in regard to hyperglycemic state and diabetes duration.Female T2DM patients (n = 146 were enrolled in the MIKRODIAB study and allocated in two groups regarding their glycated hemoglobin (HbA1c level (HbA1c≤7.5%, n = 74; HbA1c>7.5%, n = 72. In addition, tertiles according to diabetes duration (DD were created (DDI = 6.94±3.1 y, n = 49; DDII = 13.35±1.1 y, n = 48; DDIII = 22.90±7.3 y, n = 49. Oxidative stress parameters, including ferric reducing ability potential, malondialdehyde, oxidized and reduced glutathione, reduced thiols, oxidized LDL and F2-Isoprostane as well as the activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase were measured. Damage to DNA was analyzed in peripheral blood mononuclear cells and whole blood with single cell gel electrophoresis. DNA base excision repair capacity was tested with the modified comet repair assay. Additionally, mRNA expressions of nine genes related to base excision repair were analyzed in a subset of 46 matched individuals.No significant differences in oxidative stress parameters, antioxidant enzyme activities, damage to DNA and base excision repair capacity, neither between a HbA1c cut off />7.5%, nor between diabetes duration was found. A significant up-regulation in mRNA expression was found for APEX1, LIG3 and XRCC1 in patients with >7.5% HbA1c. Additionally, we observed higher total cholesterol, LDL-cholesterol, LDL/HDL-cholesterol, triglycerides, Framingham risk score, systolic blood pressure, BMI and lower HDL-cholesterol in the hyperglycemic group.BMI, blood pressure and blood lipid status were worse in hyperglycemic individuals. However, no major disparities regarding oxidative stress, damage to DNA and DNA repair were present which might be due to good medical

  4. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Juanjuan; Zhang, Yu [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); Xu, Wentao, E-mail: xuwentaoboy@sina.com [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Luo, YunBo [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Hao, Junran [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); Shen, Xiao Li [The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Yang, Xuan [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); Li, Xiaohong [The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Huang, Kunlun, E-mail: hkl009@163.com [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China)

    2013-04-15

    Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψ{sub m}). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. - Highlights: ► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by

  5. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A

    International Nuclear Information System (INIS)

    Zheng, Juanjuan; Zhang, Yu; Xu, Wentao; Luo, YunBo; Hao, Junran; Shen, Xiao Li; Yang, Xuan; Li, Xiaohong; Huang, Kunlun

    2013-01-01

    Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψ m ). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. - Highlights: ► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by OTA in

  6. Bisphenol a promotes cell survival following oxidative DNA damage in mouse fibroblasts.

    Directory of Open Access Journals (Sweden)

    Natalie R Gassman

    Full Text Available Bisphenol A (BPA is a biologically active industrial chemical used in production of consumer products. BPA has become a target of intense public scrutiny following concerns about its association with human diseases such as obesity, diabetes, reproductive disorders, and cancer. Recent studies link BPA with the generation of reactive oxygen species, and base excision repair (BER is responsible for removing oxidatively induced DNA lesions. Yet, the relationship between BPA and BER has yet to be examined. Further, the ubiquitous nature of BPA allows continuous exposure of the human genome concurrent with the normal endogenous and exogenous insults to the genome, and this co-exposure may impact the DNA damage response and repair. To determine the effect of BPA exposure on base excision repair of oxidatively induced DNA damage, cells compromised in double-strand break repair were treated with BPA alone or co-exposed with either potassium bromate (KBrO3 or laser irradiation as oxidative damaging agents. In experiments with KBrO3, co-treatment with BPA partially reversed the KBrO3-induced cytotoxicity observed in these cells, and this was coincident with an increase in guanine base lesions in genomic DNA. The improvement in cell survival and the increase in oxidatively induced DNA base lesions were reminiscent of previous results with alkyl adenine DNA glycosylase-deficient cells, suggesting that BPA may prevent initiation of repair of oxidized base lesions. With laser irradiation-induced DNA damage, treatment with BPA suppressed DNA repair as revealed by several indicators. These results are consistent with the hypothesis that BPA can induce a suppression of oxidized base lesion DNA repair by the base excision repair pathway.

  7. Single Molecule Scanning of DNA Radiation Oxidative Damage, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal will develop an assay to map genomic DNA, at the single molecule level and in a nanodevice, for oxidative DNA damage arising from radiation exposure;...

  8. Repair of oxidative DNA damage by amino acids.

    Science.gov (United States)

    Milligan, J R; Aguilera, J A; Ly, A; Tran, N Q; Hoang, O; Ward, J F

    2003-11-01

    Guanyl radicals, the product of the removal of a single electron from guanine, are produced in DNA by the direct effect of ionizing radiation. We have produced guanyl radicals in DNA by using the single electron oxidizing agent (SCN)2-, itself derived from the indirect effect of ionizing radiation via thiocyanate scavenging of OH. We have examined the reactivity of guanyl radicals in plasmid DNA with the six most easily oxidized amino acids cysteine, cystine, histidine, methionine, tryptophan and tyrosine and also simple ester and amide derivatives of them. Cystine and histidine derivatives are unreactive. Cysteine, methionine, tyrosine and particularly tryptophan derivatives react to repair guanyl radicals in plasmid DNA with rate constants in the region of approximately 10(5), 10(5), 10(6) and 10(7) dm3 mol(-1) s(-1), respectively. The implication is that amino acid residues in DNA binding proteins such as histones might be able to repair by an electron transfer reaction the DNA damage produced by the direct effect of ionizing radiation or by other oxidative insults.

  9. Dietary Berries and Ellagic Acid Prevent Oxidative DNA Damage and Modulate Expression of DNA Repair Genes

    Directory of Open Access Journals (Sweden)

    Ramesh C. Gupta

    2008-03-01

    Full Text Available DNA damage is a pre-requisite for the initiation of cancer and agents that reduce this damage are useful in cancer prevention. In this study, we evaluated the ability of whole berries and berry phytochemical, ellagic acid to reduce endogenous oxidative DNA damage. Ellagic acid was selected based on > 95% inhibition of 8-oxodeoxyguosine (8-oxodG and other unidentified oxidative DNA adducts induced by 4-hydroxy-17B;-estradiol and CuCl2 in vitro. Inhibition of the latter occurred at lower concentrations (10 u(microM than that for 8-oxodG (100 u(microM. In the in vivo study, female CD-1 mice (n=6 were fed either a control diet or diet supplemented with ellagic acid (400 ppm and dehydrated berries (5% w/w with varying ellagic acid contents -- blueberry (low, strawberry (medium and red raspberry (high, for 3 weeks. Blueberry and strawberry diets showed moderate reductions in endogenous DNA adducts (25%. However, both red raspberry and ellagic acid diets showed a significant reduction of 59% (p < 0.001 and 48% (p < 0.01, respectively. Both diets also resulted in a 3-8 fold over-expression of genes involved in DNA repair such as xeroderma pigmentosum group A complementing protein (XPA, DNA excision repair protein (ERCC5 and DNA ligase III (DNL3. These results suggest that red raspberry and ellagic acid reduce endogenous oxidative DNA damage by mechanisms which may involve increase in DNA repair.

  10. Immunochemical detection of oxidatively damaged DNA

    Czech Academy of Sciences Publication Activity Database

    Rössner ml., Pavel; Šrám, Radim

    2012-01-01

    Roč. 46, č. 4 (2012), s. 492-522 ISSN 1071-5762 R&D Projects: GA MŽP(CZ) SP/1B3/50/07; GA MŠk 2B08005; GA ČR GAP503/11/0084 Institutional research plan: CEZ:AV0Z50390703 Institutional support: RVO:68378041 Keywords : oxidative DNA damage * ELISA * immunohistochemistry Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 3.279, year: 2012

  11. The basic chemistry of exercise-induced DNA oxidation: oxidative damage, redox signalling and their interplay

    Directory of Open Access Journals (Sweden)

    James Nathan Cobley

    2015-06-01

    Full Text Available Acute exercise increases reactive oxygen and nitrogen species generation. This phenomenon is associated with two major outcomes: (1 redox signalling and (2 macromolecule damage. Mechanistic knowledge of how exercise-induced redox signalling and macromolecule damage are interlinked is limited. This review focuses on the interplay between exercise-induced redox signalling and DNA damage, using hydroxyl radical (·OH and hydrogen peroxide (H2O2 as exemplars. It is postulated that the biological fate of H2O2 links the two processes and thus represents a bifurcation point between redox signalling and damage. Indeed, H2O2 can participate in two electron signalling reactions but its diffusion and chemical properties permit DNA oxidation following reaction with transition metals and ·OH generation. It is also considered that the sensing of DNA oxidation by repair proteins constitutes a non-canonical redox signalling mechanism. Further layers of interaction are provided by the redox regulation of DNA repair proteins and their capacity to modulate intracellular H2O2 levels. Overall, exercise-induced redox signalling and DNA damage may be interlinked to a greater extent than was previously thought but this requires further investigation.

  12. Assessment of evidence for nanosized titanium dioxide-generated DNA strand breaks and oxidatively damaged DNA in cells and animal models

    DEFF Research Database (Denmark)

    Møller, Peter; Jensen, Ditte Marie; Wils, Regitze Sølling

    2017-01-01

    Nanosized titanium dioxide (TiO2) has been investigated in numerous studies on genotoxicity, including comet assay endpoints and oxidatively damaged DNA in cell cultures and animal models. The results have been surprisingly mixed, which might be attributed to physico-chemical differences...... culture studies also demonstrate increased levels of oxidatively damaged DNA after exposure to TiO2. There are relatively few studies on animal models where DNA strand breaks and oxidatively damaged DNA have been tested with reliable methods. Collectively, this review shows that exposure to nanosized TiO2...... of the tested TiO2. In the present review, we assess the role of certain methodological issues and publication bias. The analysis shows that studies on DNA strand breaks without proper assay controls or very low intra-group variation tend to show statistically significant effects. Levels of oxidatively damaged...

  13. Cancer risk and oxidative DNA damage in man

    DEFF Research Database (Denmark)

    Loft, S; Poulsen, H E

    1996-01-01

    with a mechanistically based increased risk of cancer, including Fanconi anemia, chronic hepatitis, cystic fibrosis, and various autoimmune diseases, the biomarker studies indicate an increased rate of oxidative DNA damage or in some instances deficient repair. Human studies support the experimentally based notion...

  14. The effect of obstructive sleep apnea on DNA damage and oxidative stress.

    Science.gov (United States)

    Kang, Il Gyu; Jung, Joo Hyun; Kim, Seon Tae

    2013-06-01

    Obstructive sleep apnea syndrome (OSAS) is associated with repeated hypoxia and re-oxygenation. This characteristic of OSAS may cause oxidative stress and DNA damage. However, the link of OSAS with oxidative stress and DNA damage is still controversial. In the current study, we investigated whether OSAS causes DNA damage using alkaline single-cell gel electrophoresis (comet assay) and measuring oxidative stress by monitoring serum malondialdehyde (MDA) levels. From March 2009 to August 2010, 51 patients who underwent polysomnography (PSG) during the night were enrolled in this study. We obtained serum from the patients at 6 AM. DNA damage and oxidative stress were evaluated using a comet assay and measuring serum MDA, respectively. We divided the patients into two groups according to the existence of comets appearing in the comet assay. Group 1 included 44 patients with negative assay results and group 2 consisted of seven patients with positive comet assay findings. We compared the age, gender proportion, PSG data (respiratory disturbance index [RDI], lowest O2 saturation level, and arousal index [AI]), time of disease onset, smoking habits, and serum MDA levels between the two groups. The average age and gender proportion of the two groups were not statistically different (P>0.05). The average of RDI for group 1 was 30.4±18.4 and 8.0±7.7 (P0.05). No relationship between positive comet assay results and OSAS severity was identified. Results of the current study showed that OSAS was not associated with DNA damage as measured by comet assays or oxidative stress according to serum MDA levels.

  15. DNA damage in neurodegenerative diseases

    Energy Technology Data Exchange (ETDEWEB)

    Coppedè, Fabio, E-mail: fabio.coppede@med.unipi.it; Migliore, Lucia, E-mail: lucia.migliore@med.unipi.it

    2015-06-15

    Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

  16. DNA damage in neurodegenerative diseases

    International Nuclear Information System (INIS)

    Coppedè, Fabio; Migliore, Lucia

    2015-01-01

    Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

  17. Peroxiredoxin 1 Protects Telomeres from Oxidative Damage and Preserves Telomeric DNA for Extension by Telomerase

    Directory of Open Access Journals (Sweden)

    Eric Aeby

    2016-12-01

    Full Text Available Oxidative damage of telomeres can promote cancer, cardiac failure, and muscular dystrophy. Specific mechanisms protecting telomeres from oxidative damage have not been described. We analyzed telomeric chromatin composition during the cell cycle and show that the antioxidant enzyme peroxiredoxin 1 (PRDX1 is enriched at telomeres during S phase. Deletion of the PRDX1 gene leads to damage of telomeric DNA upon oxidative stress, revealing a protective function of PRDX1 against oxidative damage at telomeres. We also show that the oxidized nucleotide 8-oxo-2′deoxyguanosine-5′-triphosphate (8oxodGTP causes premature chain termination when incorporated by telomerase and that some DNA substrates terminating in 8oxoG prevent extension by telomerase. Thus, PRDX1 safeguards telomeres from oxygen radicals to counteract telomere damage and preserve telomeric DNA for elongation by telomerase.

  18. An ECVAG trial on assessment of oxidative damage to DNA measured by the comet assay

    DEFF Research Database (Denmark)

    Johansson, Clara; Møller, Peter; Forchhammer, Lykke

    2010-01-01

    The increasing use of single cell gel electrophoresis (the comet assay) highlights its popularity as a method for detecting DNA damage, including the use of enzymes for assessment of oxidatively damaged DNA. However, comparison of DNA damage levels between laboratories can be difficult due...... to differences in assay protocols (e.g. lysis conditions, enzyme treatment, the duration of the alkaline treatment and electrophoresis) and in the end points used for reporting results (e.g. %DNA in tail, arbitrary units, tail moment and tail length). One way to facilitate comparisons is to convert primary comet...... assay end points to number of lesions/10(6) bp by calibration with ionizing radiation. The aim of this study was to investigate the inter-laboratory variation in assessment of oxidatively damaged DNA by the comet assay in terms of oxidized purines converted to strand breaks with formamidopyrimidine DNA...

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

    Science.gov (United States)

    Berger, N Daniel; Stanley, Fintan K T; Moore, Shaun; Goodarzi, Aaron A

    2017-10-05

    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'. © 2017 The Author(s).

  20. Biomarkers of oxidative damage to DNA and repair

    DEFF Research Database (Denmark)

    Loft, Steffen; Høgh Danielsen, Pernille; Mikkelsen, Lone

    2008-01-01

    environmental factors, including particulate air pollution, cause oxidative damage to DNA, whereas diets rich in fruit and vegetables or antioxidant supplements may reduce the levels and enhance repair. Urinary excretion of 8-oxodG, genotype and expression of OGG1 have been associated with risk of cancer...

  1. Oxidative stress and inflammation generated DNA damage by exposure to air pollution particles

    DEFF Research Database (Denmark)

    Møller, Peter; Danielsen, Pernille Høgh; Karottki, Dorina Gabriela

    2014-01-01

    at different locations (spatial variability), times (temporal variability) or particle size fraction across different experimental systems of acellular conditions, cultured cells, animals and humans. Nevertheless, there is substantial variation in the genotoxic, inflammation and oxidative stress potential......Generation of oxidatively damaged DNA by particulate matter (PM) is hypothesized to occur via production of reactive oxygen species (ROS) and inflammation. We investigated this hypothesis by comparing ROS production, inflammation and oxidatively damaged DNA in different experimental systems...... investigating air pollution particles. There is substantial evidence indicating that exposure to air pollution particles was associated with elevated levels of oxidatively damaged nucleobases in circulating blood cells and urine from humans, which is supported by observations of elevated levels of genotoxicity...

  2. Age-dependent oxidative stress-induced DNA damage in Down's lymphocytes

    International Nuclear Information System (INIS)

    Zana, Marianna; Szecsenyi, Anita; Czibula, Agnes; Bjelik, Annamaria; Juhasz, Anna; Rimanoczy, Agnes; Szabo, Krisztina; Vetro, Agnes; Szucs, Peter; Varkonyi, Agnes; Pakaski, Magdolna; Boda, Krisztina; Rasko, Istvan; Janka, Zoltan; Kalman, Janos

    2006-01-01

    The aim of the present study was to investigate the oxidative status of lymphocytes from children (n = 7) and adults (n = 18) with Down's syndrome (DS). The basal oxidative condition, the vulnerability to in vitro hydrogen peroxide exposure, and the repair capacity were measured by means of the damage-specific alkaline comet assay. Significantly and age-independently elevated numbers of single strand breaks and oxidized bases (pyrimidines and purines) were found in the nuclear DNA of the lymphocytes in the DS group in the basal condition. These results may support the role of an increased level of endogenous oxidative stress in DS and are similar to those previously demonstrated in Alzheimer's disease. In the in vitro oxidative stress-induced state, a markedly higher extent of DNA damage was observed in DS children as compared with age- and gender-matched healthy controls, suggesting that young trisomic lymphocytes are more sensitive to oxidative stress than normal ones. However, the repair ability itself was not found to be deteriorated in either DS children or DS adults

  3. Oxidative damage to DNA and lipids as biomarkers of exposure to air pollution

    DEFF Research Database (Denmark)

    Møller, Peter; Loft, Steffen

    2010-01-01

    BACKGROUND: Air pollution is thought to exert health effects through oxidative stress, which causes damage to DNA and lipids. OBJECTIVE: We determined whether levels of oxidatively damaged DNA and lipid peroxidation products in cells or bodily fluids from humans are useful biomarkers...... of biologically effective dose in studies of the health effects of exposure to particulate matter (PM) from combustion processes. DATA SOURCES: We identified publications that reported estimated associations between environmental exposure to PM and oxidative damage to DNA and lipids in PubMed and EMBASE. We also...... identified publications from reference lists and articles cited in the Web of Science. DATA EXTRACTION: For each study, we obtained information on the estimated effect size to calculate the standardized mean difference (unitless) and determined the potential for errors in exposure assessment and analysis...

  4. Oxidative DNA damage in lung tissue from patients with COPD is clustered in functionally significant sequences

    Directory of Open Access Journals (Sweden)

    Viktor M Pastukh

    2011-03-01

    Full Text Available Viktor M Pastukh1, Li Zhang2, Mykhaylo V Ruchko1, Olena Gorodnya1, Gina C Bardwell1, Rubin M Tuder2, Mark N Gillespie11Department of Pharmacology and Center for Lung Biology, University of South Alabama College of Medicine, Mobile, AL, USA; 2Program in Translational Lung Research, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado at Denver, Aurora, CO, USAAbstract: Lung tissue from COPD patients displays oxidative DNA damage. The present study determined whether oxidative DNA damage was randomly distributed or whether it was localized in specific sequences in either the nuclear or mitochondrial genomes. The DNA damage-specific histone, gamma-H2AX, was detected immunohistochemically in alveolar wall cells in lung tissue from COPD patients but not control subjects. A PCR-based method was used to search for oxidized purine base products in selected 200 bp sequences in promoters and coding regions of the VEGF, TGF-β1, HO-1, Egr1, and β-actin genes while quantitative Southern blot analysis was used to detect oxidative damage to the mitochondrial genome in lung tissue from control subjects and COPD patients. Among the nuclear genes examined, oxidative damage was detected in only 1 sequence in lung tissue from COPD patients: the hypoxic response element (HRE of the VEGF promoter. The content of VEGF mRNA also was reduced in COPD lung tissue. Mitochondrial DNA content was unaltered in COPD lung tissue, but there was a substantial increase in mitochondrial DNA strand breaks and/or abasic sites. These findings show that oxidative DNA damage in COPD lungs is prominent in the HRE of the VEGF promoter and in the mitochondrial genome and raise the intriguing possibility that genome and sequence-specific oxidative DNA damage could contribute to transcriptional dysregulation and cell fate decisions in COPD.Keywords: DNA damage, VEGF hypoxic response element, mtDNA, COPD

  5. Oxidative DNA damage and its repair in rat spleen following subchronic exposure to aniline

    International Nuclear Information System (INIS)

    Ma Huaxian; Wang Jianling; Abdel-Rahman, Sherif Z.; Boor, Paul J.; Khan, M. Firoze

    2008-01-01

    The mechanisms by which aniline exposure elicits splenotoxic response, especially the tumorigenic response, are not well-understood. Splenotoxicity of aniline is associated with iron overload and generation of reactive oxygen species (ROS) which can cause oxidative damage to DNA, proteins and lipids (oxidative stress). 8-Hydroxy-2'-deoxyguanosine (8-OHdG) is one of the most abundant oxidative DNA lesions resulting from ROS, and 8-oxoguanine glycosylase 1 (OGG1), a specific DNA glycosylase/lyase enzyme, plays a key role in the removal of 8-OHdG adducts. This study focused on examining DNA damage (8-OHdG) and repair (OGG1) in the spleen in an experimental condition preceding a tumorigenic response. To achieve that, male Sprague-Dawley rats were subchronically exposed to aniline (0.5 mmol/kg/day via drinking water for 30 days), while controls received drinking water only. Aniline treatment led to a significant increase in splenic oxidative DNA damage, manifested as a 2.8-fold increase in 8-OHdG levels. DNA repair activity, measured as OGG1 base excision repair (BER) activity, increased by ∼ 1.3 fold in the nuclear protein extracts (NE) and ∼ 1.2 fold in the mitochondrial protein extracts (ME) of spleens from aniline-treated rats as compared to the controls. Real-time PCR analysis for OGG1 mRNA expression in the spleen revealed a 2-fold increase in expression in aniline-treated rats than the controls. Likewise, OGG1 protein expression in the NEs of spleens from aniline-treated rats was ∼ 1.5 fold higher, whereas in the MEs it was ∼ 1.3 fold higher than the controls. Aniline treatment also led to stronger immunostaining for both 8-OHdG and OGG1 in the spleens, confined to the red pulp areas. It is thus evident from our studies that aniline-induced oxidative stress is associated with increased oxidative DNA damage. The BER pathway was also activated, but not enough to prevent the accumulation of oxidative DNA damage (8-OHdG). Accumulation of mutagenic oxidative

  6. Environmental ozone exposure and oxidative DNA damage in adult residents of Florence, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Palli, Domenico, E-mail: d.palli@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Sera, Francesco, E-mail: f.sera@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Giovannelli, Lisa, E-mail: lisag@pharm.unifi.i [Department of Pharmacology, University of Florence, Viale G.Pieraccini 6, 50139 Florence (Italy); Masala, Giovanna, E-mail: g.masala@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Grechi, Daniele [Regional Environmental Protection Agency of Tuscany (ARPAT), Via Porpora 22, 50144 Florence (Italy); Bendinelli, Benedetta, E-mail: b.bendinelli@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Caini, Saverio, E-mail: s.caini@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Dolara, Piero, E-mail: piero.dolara@unifi.i [Department of Pharmacology, University of Florence, Viale G.Pieraccini 6, 50139 Florence (Italy); Saieva, Calogero, E-mail: c.saieva@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy)

    2009-05-15

    In 71 adults residing in Florence, Italy, enrolled in a prospective study, we investigated the correlation between individual levels of oxidative DNA damage detected by the Comet assay in circulating lymphocytes, and a specific ozone exposure score calculated in 10 different time-windows (0-5 to 0-90 days) before blood drawing, based on daily measurements provided by the local environmental monitoring system. Overall, statistically significant positive correlations between average ozone concentrations and DNA damage emerged in almost all time-windows considered; correlations were more evident among males, non-smokers, and traffic-exposed workers. Multivariate regression analyses taking into account selected individual characteristics, showed an independent effect on DNA damage of average ozone concentrations in the last 60-90 days before blood drawing. Local residents showed a divergent pattern with correlations restricted to shorter time-windows. Our results suggest that ozone concentrations at ground levels modulate oxidative DNA damage in circulating lymphocytes of residents of polluted areas. - Ozone concentrations over the 60-90 days before blood drawing correlated with DNA damage in circulating lymphocytes of adults living in the metropolitan area of Florence, Italy.

  7. Environmental ozone exposure and oxidative DNA damage in adult residents of Florence, Italy

    International Nuclear Information System (INIS)

    Palli, Domenico; Sera, Francesco; Giovannelli, Lisa; Masala, Giovanna; Grechi, Daniele; Bendinelli, Benedetta; Caini, Saverio; Dolara, Piero; Saieva, Calogero

    2009-01-01

    In 71 adults residing in Florence, Italy, enrolled in a prospective study, we investigated the correlation between individual levels of oxidative DNA damage detected by the Comet assay in circulating lymphocytes, and a specific ozone exposure score calculated in 10 different time-windows (0-5 to 0-90 days) before blood drawing, based on daily measurements provided by the local environmental monitoring system. Overall, statistically significant positive correlations between average ozone concentrations and DNA damage emerged in almost all time-windows considered; correlations were more evident among males, non-smokers, and traffic-exposed workers. Multivariate regression analyses taking into account selected individual characteristics, showed an independent effect on DNA damage of average ozone concentrations in the last 60-90 days before blood drawing. Local residents showed a divergent pattern with correlations restricted to shorter time-windows. Our results suggest that ozone concentrations at ground levels modulate oxidative DNA damage in circulating lymphocytes of residents of polluted areas. - Ozone concentrations over the 60-90 days before blood drawing correlated with DNA damage in circulating lymphocytes of adults living in the metropolitan area of Florence, Italy.

  8. Acute hypoxia and hypoxic exercise induce DNA strand breaks and oxidative DNA damage in humans

    DEFF Research Database (Denmark)

    Møller, P; Loft, S; Lundby, C

    2001-01-01

    ; lymphocytes were isolated for analysis of DNA strand breaks and oxidatively altered nucleotides, detected by endonuclease III and formamidipyridine glycosylase (FPG) enzymes. Urine was collected for 24 h periods for analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a marker of oxidative DNA damage...... oxygen species, generated by leakage of the mitochondrial respiration or during a hypoxia-induced inflammation. Furthermore, the presence of DNA strand breaks may play an important role in maintaining hypoxia-induced inflammation processes. Hypoxia seems to deplete the antioxidant system of its capacity...

  9. Role of oxidative DNA damage in genome instability and cancer

    International Nuclear Information System (INIS)

    Bignami, M.; Kunkel, T.

    2009-01-01

    Inactivation of mismatch repair (MMR) is associated with a dramatic genomic instability that is observed experimentally as a mutator phenotype and micro satellite instability (MSI). It has been implicit that the massive genetic instability in MMR defective cells simply reflects the accumulation of spontaneous DNA polymerase errors during DNA replication. We recently identified oxidation damage, a common threat to DNA integrity to which purines are very susceptible, as an important cofactor in this genetic instability

  10. Enzymatic recognition of DNA damage induced by UVB-photosensitized titanium dioxide and biological consequences in Saccharomyces cerevisiae: Evidence for oxidatively DNA damage generation

    International Nuclear Information System (INIS)

    Pinto, A. Viviana; Deodato, Elder L.; Cardoso, Janine S.; Oliveira, Eliza F.; Machado, Sergio L.; Toma, Helena K.; Leitao, Alvaro C.; Padula, Marcelo de

    2010-01-01

    Although titanium dioxide (TiO 2 ) has been considered to be biologically inert, finding use in cosmetics, paints and food colorants, recent reports have demonstrated that when TiO 2 is attained by UVA radiation oxidative genotoxic and cytotoxic effects are observed in living cells. However, data concerning TiO 2 -UVB association is poor, even if UVB radiation represents a major environmental carcinogen. Herein, we investigated DNA damage, repair and mutagenesis induced by TiO 2 associated with UVB irradiation in vitro and in vivo using Saccharomyces cerevisiae model. It was found that TiO 2 plus UVB treatment in plasmid pUC18 generated, in addition to cyclobutane pyrimidine dimers (CPDs), specific damage to guanine residues, such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), which are characteristic oxidatively generated lesions. In vivo experiments showed that, although the presence of TiO 2 protects yeast cells from UVB cytotoxicity, high mutation frequencies are observed in the wild-type (WT) and in an ogg1 strain (deficient in 8-oxoG and FapyG repair). Indeed, after TiO 2 plus UVB treatment, induced mutagenesis was drastically enhanced in ogg1 cells, indicating that mutagenic DNA lesions are repaired by the Ogg1 protein. This effect could be attenuated by the presence of metallic ion chelators: neocuproine or dipyridyl, which partially block oxidatively generated damage occurring via Fenton reactions. Altogether, the results indicate that TiO 2 plus UVB potentates UVB oxidatively generated damage to DNA, possibly via Fenton reactions involving the production of DNA base damage, such as 8-oxo-7,8-dihydroguanine.

  11. Carnosine attenuates cyclophosphamide-induced bone marrow suppression by reducing oxidative DNA damage

    Directory of Open Access Journals (Sweden)

    Jie Deng

    2018-04-01

    Full Text Available Oxidative DNA damage in bone marrow cells is the main side effect of chemotherapy drugs including cyclophosphamide (CTX. However, not all antioxidants are effective in inhibiting oxidative DNA damage. In this study, we report the beneficial effect of carnosine (β-alanyl-l-histidine, a special antioxidant with acrolein-sequestering ability, on CTX-induced bone marrow cell suppression. Our results show that carnosine treatment (100 and 200 mg/kg, i.p. significantly inhibited the generation of reactive oxygen species (ROS and 8-hydroxy-2′-deoxyguanosine (8-oxo-dG, and decreased chromosomal abnormalities in the bone marrow cells of mice treated with CTX (20 mg/kg, i.v., 24 h. Furthermore, carnosine evidently mitigated CTX-induced G2/M arrest in murine bone marrow cells, accompanied by reduced ratios of p-Chk1/Chk1 and p-p53/p53 as well as decreased p21 expression. In addition, cell apoptosis caused by CTX was also suppressed by carnosine treatment, as assessed by decreased TUNEL-positive cell counts, down-regulated expressions of Bax and Cyt c, and reduced ratios of cleaved Caspase-3/Caspase-3. These results together suggest that carnosine can protect murine bone marrow cells from CTX-induced DNA damage via its antioxidant activity. Keywords: Carnosine, Cyclophosphamide, Oxidative DNA damage, Sister chromatid exchange, Apoptosis, Cell cycle arrest

  12. Enzymatic recognition of DNA damage induced by UVB-photosensitized titanium dioxide and biological consequences in Saccharomyces cerevisiae: evidence for oxidatively DNA damage generation.

    Science.gov (United States)

    Pinto, A Viviana; Deodato, Elder L; Cardoso, Janine S; Oliveira, Eliza F; Machado, Sérgio L; Toma, Helena K; Leitão, Alvaro C; de Pádula, Marcelo

    2010-06-01

    Although titanium dioxide (TiO(2)) has been considered to be biologically inert, finding use in cosmetics, paints and food colorants, recent reports have demonstrated that when TiO(2) is attained by UVA radiation oxidative genotoxic and cytotoxic effects are observed in living cells. However, data concerning TiO(2)-UVB association is poor, even if UVB radiation represents a major environmental carcinogen. Herein, we investigated DNA damage, repair and mutagenesis induced by TiO(2) associated with UVB irradiation in vitro and in vivo using Saccharomyces cerevisiae model. It was found that TiO(2) plus UVB treatment in plasmid pUC18 generated, in addition to cyclobutane pyrimidine dimers (CPDs), specific damage to guanine residues, such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), which are characteristic oxidatively generated lesions. In vivo experiments showed that, although the presence of TiO(2) protects yeast cells from UVB cytotoxicity, high mutation frequencies are observed in the wild-type (WT) and in an ogg1 strain (deficient in 8-oxoG and FapyG repair). Indeed, after TiO(2) plus UVB treatment, induced mutagenesis was drastically enhanced in ogg1 cells, indicating that mutagenic DNA lesions are repaired by the Ogg1 protein. This effect could be attenuated by the presence of metallic ion chelators: neocuproine or dipyridyl, which partially block oxidatively generated damage occurring via Fenton reactions. Altogether, the results indicate that TiO(2) plus UVB potentates UVB oxidatively generated damage to DNA, possibly via Fenton reactions involving the production of DNA base damage, such as 8-oxo-7,8-dihydroguanine. Copyright 2010 Elsevier B.V. All rights reserved.

  13. Enzymatic recognition of DNA damage induced by UVB-photosensitized titanium dioxide and biological consequences in Saccharomyces cerevisiae: Evidence for oxidatively DNA damage generation

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, A. Viviana, E-mail: alicia.pinto@incqs.fiocruz.br [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil); Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Deodato, Elder L. [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil); Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Cardoso, Janine S. [Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Oliveira, Eliza F.; Machado, Sergio L.; Toma, Helena K. [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil); Leitao, Alvaro C. [Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Padula, Marcelo de [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil)

    2010-06-01

    Although titanium dioxide (TiO{sub 2}) has been considered to be biologically inert, finding use in cosmetics, paints and food colorants, recent reports have demonstrated that when TiO{sub 2} is attained by UVA radiation oxidative genotoxic and cytotoxic effects are observed in living cells. However, data concerning TiO{sub 2}-UVB association is poor, even if UVB radiation represents a major environmental carcinogen. Herein, we investigated DNA damage, repair and mutagenesis induced by TiO{sub 2} associated with UVB irradiation in vitro and in vivo using Saccharomyces cerevisiae model. It was found that TiO{sub 2} plus UVB treatment in plasmid pUC18 generated, in addition to cyclobutane pyrimidine dimers (CPDs), specific damage to guanine residues, such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), which are characteristic oxidatively generated lesions. In vivo experiments showed that, although the presence of TiO{sub 2} protects yeast cells from UVB cytotoxicity, high mutation frequencies are observed in the wild-type (WT) and in an ogg1 strain (deficient in 8-oxoG and FapyG repair). Indeed, after TiO{sub 2} plus UVB treatment, induced mutagenesis was drastically enhanced in ogg1 cells, indicating that mutagenic DNA lesions are repaired by the Ogg1 protein. This effect could be attenuated by the presence of metallic ion chelators: neocuproine or dipyridyl, which partially block oxidatively generated damage occurring via Fenton reactions. Altogether, the results indicate that TiO{sub 2} plus UVB potentates UVB oxidatively generated damage to DNA, possibly via Fenton reactions involving the production of DNA base damage, such as 8-oxo-7,8-dihydroguanine.

  14. Nickel exposure induces oxidative damage to mitochondrial DNA in Neuro2a cells: the neuroprotective roles of melatonin.

    Science.gov (United States)

    Xu, Shang-Cheng; He, Min-Di; Lu, Yong-Hui; Li, Li; Zhong, Min; Zhang, Yan-Wen; Wang, Yuan; Yu, Zheng-Ping; Zhou, Zhou

    2011-11-01

    Recent studies suggest that oxidative stress and mitochondrial dysfunction play important roles in the neurotoxicity of nickel. Because mitochondrial DNA (mtDNA) is highly vulnerable to oxidative stress and melatonin can efficiently protect mtDNA against oxidative damage in various pathological conditions, the aims of this study were to determine whether mtDNA oxidative damage was involved in the neurotoxicity of nickel and to assay the neuroprotective effects of melatonin in mtDNA. In this study, we exposed mouse neuroblastoma cell lines (Neuro2a) to different concentrations of nickel chloride (NiCl(2), 0.125, 0.25, and 0.5 mm) for 24 hr. We found that nickel significantly increased reactive oxygen species (ROS) production and mitochondrial superoxide levels. In addition, nickel exposure increased mitochondrial 8-hydroxyguanine (8-OHdG) content and reduced mtDNA content and mtDNA transcript levels. Consistent with this finding, nickel was found to destroy mtDNA nucleoid structure and decrease protein levels of Tfam, a key protein component for nucleoid organization. However, all the oxidative damage to mtDNA induced by nickel was efficiently attenuated by melatonin pretreatment. Our results suggest that oxidative damage to mtDNA may account for the neurotoxicity of nickel. Melatonin has great pharmacological potential in protecting mtDNA against the adverse effects of nickel in the nervous system. © 2011 John Wiley & Sons A/S.

  15. Mitochondrial DNA damage and oxidative damage in HL-60 cells exposed to 900 MHz radiofrequency fields

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yulong; Zong, Lin; Gao, Zhen [School of Public Health, Soochow University, Suzhou, Jiangsu Province (China); Zhu, Shunxing [Laboratory Animal Center, Nantong University, Nantong, Jiangsu Province (China); Tong, Jian [School of Public Health, Soochow University, Suzhou, Jiangsu Province (China); Cao, Yi, E-mail: yicao@suda.edu.cn [School of Public Health, Soochow University, Suzhou, Jiangsu Province (China)

    2017-03-15

    Highlights: • Increased reactive oxygen species. • Decreased mitochondrial transcription Factor A and polymerase gamma. • Decreased mitochondrial transcripts (ND1 and 16S) and mtDNA copy number. • Increased 8-hydroxy-2′deoxyguanosine. • Decreased adenosine triphosphate. - Abstract: HL-60 cells, derived from human promyelocytic leukemia, were exposed to continuous wave 900 MHz radiofrequency fields (RF) at 120 μW/cm{sup 2} power intensity for 4 h/day for 5 consecutive days to examine whether such exposure is capable damaging the mitochondrial DNA (mtDNA) mediated through the production of reactive oxygen species (ROS). In addition, the effect of RF exposure was examined on 8-hydroxy-2′-dexoyguanosine (8-OHdG) which is a biomarker for oxidative damage and on the mitochondrial synthesis of adenosine triphosphate (ATP) which is the energy required for cellular functions. The results indicated a significant increase in ROS and significant decreases in mitochondrial transcription factor A, mtDNA polymerase gamma, mtDNA transcripts and mtDNA copy number in RF-exposed cells compared with those in sham-exposed control cells. In addition, there was a significant increase in 8-OHdG and a significant decrease in ATP in RF-exposed cells. The response in positive control cells exposed to gamma radiation (GR, which is also known to induce ROS) was similar to those in RF-exposed cells. Thus, the overall data indicated that RF exposure was capable of inducing mtDNA damage mediated through ROS pathway which also induced oxidative damage. Prior-treatment of RF- and GR-exposed the cells with melatonin, a well-known free radical scavenger, reversed the effects observed in RF-exposed cells.

  16. Replication stress and oxidative damage contribute to aberrant constitutive activation of DNA damage signalling in human gliomas

    DEFF Research Database (Denmark)

    Bartkova, J; Hamerlik, P; Stockhausen, Marie

    2010-01-01

    brain and grade II astrocytomas, despite the degree of DDR activation was higher in grade II tumors. Markers indicative of ongoing DNA replication stress (Chk1 activation, Rad17 phosphorylation, replication protein A foci and single-stranded DNA) were present in GBM cells under high- or low...... and indicate that replication stress, rather than oxidative stress, fuels the DNA damage signalling in early stages of astrocytoma development.......Malignant gliomas, the deadliest of brain neoplasms, show rampant genetic instability and resistance to genotoxic therapies, implicating potentially aberrant DNA damage response (DDR) in glioma pathogenesis and treatment failure. Here, we report on gross, aberrant constitutive activation of DNA...

  17. Oxidative DNA damage and repair in skeletal muscle of humans exposed to high-altitude hypoxia

    International Nuclear Information System (INIS)

    Lundby, Carsten; Pilegaard, Henriette; Hall, Gerrit van; Sander, Mikael; Calbet, Jose; Loft, Steffen; Moeller, Peter

    2003-01-01

    Recent research suggests that high-altitude hypoxia may serve as a model for prolonged oxidative stress in healthy humans. In this study, we investigated the consequences of prolonged high-altitude hypoxia on the basal level of oxidative damage to nuclear DNA in muscle cells, a major oxygen-consuming tissue. Muscle biopsies from seven healthy humans were obtained at sea level and after 2 and 8 weeks of hypoxia at 4100 m.a.s.l. We found increased levels of strand breaks and endonuclease III-sensitive sites after 2 weeks of hypoxia, whereas oxidative DNA damage detected by formamidopyrimidine DNA glycosylase (FPG) protein was unaltered. The expression of 8-oxoguanine DNA glycosylase 1 (OGG1), determined by quantitative RT-PCR of mRNA levels did not significantly change during high-altitude hypoxia, although the data could not exclude a minor upregulation. The expression of heme oxygenase-1 (HO-1) was unaltered by prolonged hypoxia, in accordance with the notion that HO-1 is an acute stress response protein. In conclusion, our data indicate high-altitude hypoxia may serve as a good model for oxidative stress and that antioxidant genes are not upregulated in muscle tissue by prolonged hypoxia despite increased generation of oxidative DNA damage

  18. [Endonuclease modified comet assay for oxidative DNA damage induced by detection of genetic toxicants].

    Science.gov (United States)

    Zhao, Jian; Li, Hongli; Zhai, Qingfeng; Qiu, Yugang; Niu, Yong; Dai, Yufei; Zheng, Yuxin; Duan, Huawei

    2014-03-01

    The aim of this study was to investigate the use of the lesion-specific endonucleases-modified comet assay for analysis of DNA oxidation in cell lines. DNA breaks and oxidative damage were evaluated by normal alkaline and formamidopyrimidine-DNA-glycosylase (FPG) modified comet assays. Cytotoxicity were assessed by MTT method. The human bronchial epithelial cell (16HBE) were treated with benzo (a) pyrene (B(a)P), methyl methanesulfonate (MMS), colchicine (COL) and vincristine (VCR) respectively, and the dose is 20 µmol/L, 25 mg/ml, 5 mg/L and 0.5 mg/L for 24 h, respectively. Oxidative damage was also detected by levels of reactive oxygen species in treated cells. Four genotoxicants give higher cytotoxicity and no significant changes on parameters of comet assay treated by enzyme buffer. Cell survival rate were (59.69 ± 2.60) %, (54.33 ± 2.81) %, (53.11 ± 4.00) %, (51.43 ± 3.92) % in four groups, respectively. There was the direct DNA damage induced by test genotoxicants presented by tail length, Olive tail moment (TM) and tail DNA (%) in the comet assay. The presence of FPG in the assays increased DNA migration in treated groups when compared to those without it, and the difference was statistically significant which indicated that the clastogen and aneugen could induce oxidative damage in DNA strand. In the three parameters, the Olive TM was changed most obviously after genotoxicants treatment. In the contrast group, the Olive TM of B(a) P,MMS, COL,VCR in the contrast groups were 22.99 ± 17.33, 31.65 ± 18.86, 19.86 ± 9.56 and 17.02 ± 9.39, respectively, after dealing with the FPG, the Olive TM were 34.50 ± 17.29, 43.80 ± 10.06, 33.10 ± 12.38, 28.60 ± 10.53, increased by 58.94%, 38.48%, 66.86% and 68.21%, respectively (t value was 3.91, 3.89, 6.66 and 3.87, respectively, and all P comet assay appears more specific for detecting oxidative DNA damage induced by genotoxicants exposure, and the application of comet assay will be expanded. The endonuclease

  19. Personal exposure to ultrafine particles and oxidative DNA damage

    DEFF Research Database (Denmark)

    Vinzents, Peter S; Møller, Peter; Sørensen, Mette

    2005-01-01

    10), nitrous oxide, nitrogen dioxide, carbon monoxide, and/or number concentration of UFPs at urban background or busy street monitoring stations was not a significant predictor of DNA damage, although personal UFP exposure was correlated with urban background concentrations of CO and NO2...... the morning after exposure measurement. Cumulated outdoor and cumulated indoor exposures to UFPs each were independent significant predictors of the level of purine oxidation in DNA but not of strand breaks. Ambient air concentrations of particulate matter with an aerodynamic diameter of ..., particularly during bicycling in traffic. The results indicate that biologic effects of UFPs occur at modest exposure, such as that occurring in traffic, which supports the relationship of UFPs and the adverse health effects of air pollution....

  20. Oxidative stress generated damage to DNA by gastrointestinal exposure to insoluble particles

    DEFF Research Database (Denmark)

    Møller, Peter; Folkmann, J K; Danielsen, P H

    2012-01-01

    that gastrointestinal exposure to single-walled carbon nanotubes (SWCNT), fullerenes C60, carbon black, titanium dioxide and diesel exhaust particles generates oxidized DNA base lesions in organs such as the bone marrow, liver and lung. Oral exposure to nanosized carbon black has also been associated with increased...... level of lipid peroxidation derived exocyclic DNA adducts in the liver, suggesting multiple pathways of oxidative stress for particle-generated damage to DNA. At equal dose, diesel exhaust particles (SRM2975) generated larger levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine in rat liver than carbon black...

  1. Effect of complex polyphenols and tannins from red wine (WCPT) on chemically induced oxidative DNA damage in the rat.

    Science.gov (United States)

    Casalini, C; Lodovici, M; Briani, C; Paganelli, G; Remy, S; Cheynier, V; Dolara, P

    1999-08-01

    Flavonoids are polyphenolic antioxidants occurring in vegetables and fruits as well as beverages such as tea and wine which have been thought to influence oxidative damage. We wanted to verify whether a complex mixture of wine tannins (wine complex polyphenols and tannins, WCPT) prevent chemically-induced oxidative DNA damage in vivo. Oxidative DNA damage was evaluated by measuring the ratio of 8-hydroxy-2'-deoxyguanosine (80HdG)/ 2-deoxyguanosine (2dG) x 10(-6) in hydrolyzed DNA using HPLC coupled with electrochemical and UV detectors. We treated rats with WCPT (57 mg/kg p.o.) for 14 d, a dose 10-fold higher than what a moderate wine drinker would be exposed to. WCPT administration significantly reduced the ratio of 80HdG/2dG x 10(-6) in liver DNA obtained from rats treated with 2-nitropropane (2NP) relative to controls administered 2NP only (33. 3 +/- 2.5 vs. 44.9 +/- 3.2 x 10(-6) 2dG; micro +/- SE; p<0.05). On the contrary, pretreatment with WCPT for 10 d did not protect the colon mucosa from oxidative DNA damage induced by 1, 2-dimethylhydrazine (DMH). 2NP and DMH are hepatic and colon carcinogens, respectively, capable of inducing oxidative DNA damage. WCPT have protective action against some types of chemically-induced oxidative DNA damage in vivo.

  2. Processing of free radical damaged DNA bases

    International Nuclear Information System (INIS)

    Wallace, S.

    2003-01-01

    Free radicals produced during the radiolysis of water gives rise to a plethora of DNA damages including single strand breaks, sites of base loss and a wide variety of purine and pyrimidine base lesions. All these damages are processed in cells by base excision repair. The oxidative DNA glycosylases which catalyze the first step in the removal of a base damage during base excision repair evolved primarily to protect the cells from the deleterious mutagenic effects of single free radical-induced DNA lesions arising during oxidative metabolism. This is evidenced by the high spontaneous mutation rate in bacterial mutants lacking the oxidative DNA glycosylases. However, when a low LET photon transverses the DNA molecule, a burst of free radicals is produced during the radiolysis of water that leads to the formation of clustered damages in the DNA molecule, that are recognized by the oxidative DNA glycosylases. When substrates containing two closely opposed sugar damages or base and sugar damages are incubated with the oxidative DNA glycosylases in vitro, one strand is readily incised by the lyase activity of the DNA glycosylase. Whether or not the second strand is incised depends on the distance between the strand break resulting from the incised first strand and the remaining DNA lesion on the other strand. If the lesions are more than two or three base pairs apart, the second strand is readily cleaved by the DNA glycosylase, giving rise to a double strand break. Even if the entire base excision repair system is reconstituted in vitro, whether or not a double strand break ensues depends solely upon the ability of the DNA glycosylase to cleave the second strand. These data predicted that cells deficient in the oxidative DNA glycosylases would be radioresistant while those that overproduce an oxidative DNA glycosylase would be radiosensitive. This prediction was indeed borne in Escherichia coli that is, mutants lacking the oxidative DNA glycosylases are radioresistant

  3. NEIL2 protects against oxidative DNA damage induced by sidestream smoke in human cells.

    Directory of Open Access Journals (Sweden)

    Altaf H Sarker

    Full Text Available Secondhand smoke (SHS is a confirmed lung carcinogen that introduces thousands of toxic chemicals into the lungs. SHS contains chemicals that have been implicated in causing oxidative DNA damage in the airway epithelium. Although DNA repair is considered a key defensive mechanism against various environmental attacks, such as cigarette smoking, the associations of individual repair enzymes with susceptibility to lung cancer are largely unknown. This study investigated the role of NEIL2, a DNA glycosylase excising oxidative base lesions, in human lung cells treated with sidestream smoke (SSS, the main component of SHS. To do so, we generated NEIL2 knockdown cells using siRNA-technology and exposed them to SSS-laden medium. Representative SSS chemical compounds in the medium were analyzed by mass spectrometry. An increased production of reactive oxygen species (ROS in SSS-exposed cells was detected through the fluorescent detection and the induction of HIF-1α. The long amplicon-quantitative PCR (LA-QPCR assay detected significant dose-dependent increases of oxidative DNA damage in the HPRT gene of cultured human pulmonary fibroblasts (hPF and BEAS-2B epithelial cells exposed to SSS for 24 h. These data suggest that SSS exposure increased oxidative stress, which could contribute to SSS-mediated toxicity. siRNA knockdown of NEIL2 in hPF and HEK 293 cells exposed to SSS for 24 h resulted in significantly more oxidative DNA damage in HPRT and POLB than in cells with control siRNA. Taken together, our data strongly suggest that decreased repair of oxidative DNA base lesions due to an impaired NEIL2 expression in non-smokers exposed to SSS would lead to accumulation of mutations in genomic DNA of lung cells over time, thus contributing to the onset of SSS-induced lung cancer.

  4. Three job stress models/concepts and oxidative DNA damage in a sample of workers in Japan.

    Science.gov (United States)

    Inoue, Akiomi; Kawakami, Norito; Ishizaki, Masao; Tabata, Masaji; Tsuchiya, Masao; Akiyama, Miki; Kitazume, Akiko; Kuroda, Mitsuyo; Shimazu, Akihito

    2009-04-01

    Three job stress models/concepts (the job demands-control [DC] model, the effort-reward imbalance [ERI] model, and organizational justice) have been linked to coronary heart disease (CHD) at work. In recent years, oxidative DNA damage has been identified as a new risk factor for CHD. However, evidence for the association between these job stressors and oxidative DNA damage is limited. The present cross-sectional study investigated the association between these job stress models/concepts and oxidative DNA damage as a possible mediator of the adverse health effects of job stress. A total of 166 male and 51 female workers of a manufacturing factory in Japan were surveyed using a mailed questionnaire regarding job stressors and demographic, occupational, and lifestyle variables. Urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage, were also measured. In male subjects, the urinary concentrations of 8-OHdG were significantly higher among the group with lower interactional justice, one of the two components of organizational justice; however, no association was observed with the DC model or the ERI model. In female subjects, high job demands/control ratio was significantly and positively associated with the urinary concentrations of 8-OHdG. Interactional justice among male workers and the DC model-based strain among female workers may be associated with increased urinary concentrations of 8-OHdG which possibly reflects oxidative DNA damage.

  5. Increased urinary excretion of 8-oxo-2'-deoxyguanosine, a biomarker of oxidative DNA damage, in urban bus drivers

    DEFF Research Database (Denmark)

    Loft, S; Poulsen, H E; Vistisen, K

    1999-01-01

    Oxidative damage to DNA could be involved in the increased risk of cancer associated with exposure to polluted urban air, which contains a number of oxidants. CYP1A2 is induced by and metabolizes polyaromatic hydrocarbons (PAH) and aromatic amines and could modify effects of exposure to ambient air...... pollution. Similarly, DNA repair may be influenced by occupational and other exposures as well as modify the effect of DNA damaging agents. As part of a large investigation of the genotoxic burden to diesel exposed workers in transport sectors we studied oxidative DNA damage in 57 non-smoking bus drivers...... from the greater Copenhagen area. The drivers were studied on a workday and on a day off work. Comparisons were made between drivers from the central (n=30) and rural/suburban (n=27) areas of Copenhagen. The rate of oxidative DNA damage was estimated from 24 h urinary excretion of 8-oxo-2...

  6. 2- and 4-Aminobiphenyls induce oxidative DNA damage in human hepatoma (Hep G2) cells via different mechanisms

    International Nuclear Information System (INIS)

    Wang Shuchi; Chung, Jing-Gung; Chen, C.-H.; Chen, S.-C.

    2006-01-01

    4-Aminobiphenyl (4-ABP) and its analogue, 2-aminobiphenyl (2-ABP), were examined for their ability to induce oxidative DNA damage in Hep G2 cells. Using the alkaline comet assay, we showed that 2-ABP and 4-ABP (25-200 μM) were able to induce the DNA damage in Hep G2 cells. With both compounds, formation of intracellular reactive oxygen species (ROS) was detected using flow cytometry analysis. Post-treatment of 2-ABP and 4-ABP-treated cells by endonuclease III (Endo III) or formamidopyrimidine-DNA glycosylase (Fpg) to determine the formation of oxidized pyrimidines or oxidized purines showed a significant increase of the extent of DNA migration. This indicated that oxidative DNA damage occurs in Hep G2 cells after exposure to 2-ABP and 4-ABP. This assumption was further substantiated by the fact that the spin traps, 5,5-dimethyl-pyrroline-N-oxide (DMPO) and N-tert-butyl-α-phenylnitrone (PBN), decreased DNA damage significantly. Furthermore, addition of the catalase (100 U/ml) caused a decrease in the DNA damage induced by 2-ABP or 4-ABP, indicating that H 2 O 2 is involved in ABP-induced DNA damage. Pre-incubation of the cells with the iron chelator desferrioxamine (DFO) (1 mM) and with the copper chelator neocupronine (NC) (100 μM) also decreased DNA damage in cells treated with 200 μM 2-ABP or 200 μM 4-ABP, while the calcium chelator {1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester}(BAPTA/AM) (10 μM) decreased only DNA strand breaks in cells exposed to 4-ABP. This suggested that ions are involved in the formation of DNA strand breaks. Using RT-PCR and Western blotting, lower inhibition of the expression of the OGG1 gene and of the OGG1 protein was observed in cells treated with 4-ABP, and 2-ABP-treated cells showed a marked reduction in the expression of OGG1 gene and OGG1 protein. Taken together, our finding indicated the mechanisms of induced oxidative DNA damage in Hep G2 cell by 2-ABP and 4-ABP are different, although both

  7. Hide and seek: How do DNA glycosylases locate oxidatively damaged DNA bases amidst a sea of undamaged bases?

    Science.gov (United States)

    Lee, Andrea J; Wallace, Susan S

    2017-06-01

    The first step of the base excision repair (BER) pathway responsible for removing oxidative DNA damage utilizes DNA glycosylases to find and remove the damaged DNA base. How glycosylases find the damaged base amidst a sea of undamaged bases has long been a question in the BER field. Single molecule total internal reflection fluorescence microscopy (SM TIRFM) experiments have allowed for an exciting look into this search mechanism and have found that DNA glycosylases scan along the DNA backbone in a bidirectional and random fashion. By comparing the search behavior of bacterial glycosylases from different structural families and with varying substrate specificities, it was found that glycosylases search for damage by periodically inserting a wedge residue into the DNA stack as they redundantly search tracks of DNA that are 450-600bp in length. These studies open up a wealth of possibilities for further study in real time of the interactions of DNA glycosylases and other BER enzymes with various DNA substrates. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Lack of association of colonic epithelium telomere length and oxidative DNA damage in Type 2 diabetes under good metabolic control

    Directory of Open Access Journals (Sweden)

    Kennedy Hugh

    2008-10-01

    Full Text Available Abstract Background Telomeres are DNA repeat sequences necessary for DNA replication which shorten at cell division at a rate directly related to levels of oxidative stress. Critical telomere shortening predisposes to cell senescence and to epithelial malignancies. Type 2 diabetes is characterised by increased oxidative DNA damage, telomere attrition, and an increased risk of colonic malignancy. We hypothesised that the colonic mucosa in Type 2 diabetes would be characterised by increased DNA damage and telomere shortening. Methods We examined telomere length (by flow fluorescent in situ hybridization and oxidative DNA damage (flow cytometry of 8 – oxoguanosine in the colonic mucosal cells of subjects with type 2 diabetes (n = 10; mean age 62.2 years, mean HbA1c 6.9% and 22 matched control subjects. No colonic pathology was apparent in these subjects at routine gastrointestinal investigations. Results Mean colonic epithelial telomere length in the diabetes group was not significantly different from controls (10.6 [3.6] vs. 12.1 [3.4] Molecular Equivalent of Soluble Fluorochrome Units [MESF]; P = 0.5. Levels of oxidative DNA damage were similar in both T2DM and control groups (2.6 [0.6] vs. 2.5 [0.6] Mean Fluorescent Intensity [MFI]; P = 0.7. There was no significant relationship between oxidative DNA damage and telomere length in either group (both p > 0.1. Conclusion Colonic epithelium in Type 2 diabetes does not differ significantly from control colonic epithelium in oxidative DNA damage or telomere length. There is no evidence in this study for increased oxidative DNA damage or significant telomere attrition in colonic mucosa as a carcinogenic mechanism.

  9. Fisetin Protects DNA Against Oxidative Damage and Its Possible Mechanism.

    Science.gov (United States)

    Wang, Tingting; Lin, Huajuan; Tu, Qian; Liu, Jingjing; Li, Xican

    2016-06-01

    The paper tries to assess the protective effect of fisetin against •OH-induced DNA damage, then to investigate the possible mechanism. The protective effect was evaluated based on the content of malondialdehyde (MDA). The possible mechanism was analyzed using various antioxidant methods in vitro, including •OH scavenging (deoxyribose degradation), •O2 (-) scavenging (pyrogallol autoxidation), DPPH• scavenging, ABTS•(+) scavenging, and Cu(2+)-reducing power assays. Fisetin increased dose-dependently its protective percentages against •OH-induced DNA damage (IC50 value =1535.00±29.60 µM). It also increased its radical-scavenging percentages in a dose-dependent manner in various antioxidants assays. Its IC50 values in •OH scavenging, •O2(-) scavenging, DPPH• scavenging, ABTS•(+) scavenging, and Cu(2+)-reducing power assays, were 47.41±4.50 µM, 34.05±0.87 µM, 9.69±0.53 µM, 2.43±0.14 µM, and 1.49±0.16 µM, respectively. Fisetin can effectively protect DNA against •OH-induced oxidative damage possibly via reactive oxygen species (ROS) scavenging approach, which is assumed to be hydrogen atom (H•) and/or single electron (e) donation (HAT/SET) pathways. In the HAT pathway, the 3',4'-dihydroxyl moiety in B ring of fisetin is thought to play an important role, because it can be ultimately oxidized to a stable ortho-benzoquinone form.

  10. Oxidatively-induced DNA damage and base excision repair in euthymic patients with bipolar disorder.

    Science.gov (United States)

    Ceylan, Deniz; Tuna, Gamze; Kirkali, Güldal; Tunca, Zeliha; Can, Güneş; Arat, Hidayet Ece; Kant, Melis; Dizdaroglu, Miral; Özerdem, Ayşegül

    2018-05-01

    Oxidatively-induced DNA damage has previously been associated with bipolar disorder. More recently, impairments in DNA repair mechanisms have also been reported. We aimed to investigate oxidatively-induced DNA lesions and expression of DNA glycosylases involved in base excision repair in euthymic patients with bipolar disorder compared to healthy individuals. DNA base lesions including both base and nucleoside modifications were measured using gas chromatography-tandem mass spectrometry and liquid chromatography-tandem mass spectrometry with isotope-dilution in DNA samples isolated from leukocytes of euthymic patients with bipolar disorder (n = 32) and healthy individuals (n = 51). The expression of DNA repair enzymes OGG1 and NEIL1 were measured using quantitative real-time polymerase chain reaction. The levels of malondialdehyde were measured using high performance liquid chromatography. Seven DNA base lesions in DNA of leukocytes of patients and healthy individuals were identified and quantified. Three of them had significantly elevated levels in bipolar patients when compared to healthy individuals. No elevation of lipid peroxidation marker malondialdehyde was observed. The level of OGG1 expression was significantly reduced in bipolar patients compared to healthy individuals, whereas the two groups exhibited similar levels of NEIL1 expression. Our results suggest that oxidatively-induced DNA damage occurs and base excision repair capacity may be decreased in bipolar patients when compared to healthy individuals. Measurement of oxidatively-induced DNA base lesions and the expression of DNA repair enzymes may be of great importance for large scale basic research and clinical studies of bipolar disorder. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Protection by quercetin and quercetin-rich fruit juice against induction of oxidative DNA damage and formation of BPDE-DNA adducts in human lymphocytes

    NARCIS (Netherlands)

    Wilms, L.C.; Hollman, P.C.H.; Boots, A.W.; Kleinjans, J.C.S.

    2005-01-01

    Flavonoids are claimed to protect against cardiovascular disease, certain forms of cancer and ageing, possibly by preventing initial DNA damage. Therefore, we investigated the protective effects of the flavonoid quercetin against the formation of oxidative DNA damage and bulky DNA adducts in human

  12. In Vivo Alkaline Comet Assay and Enzyme-modified Alkaline Comet Assay for Measuring DNA Strand Breaks and Oxidative DNA Damage in Rat Liver.

    Science.gov (United States)

    Ding, Wei; Bishop, Michelle E; Lyn-Cook, Lascelles E; Davis, Kelly J; Manjanatha, Mugimane G

    2016-05-04

    Unrepaired DNA damage can lead to genetic instability, which in turn may enhance cancer development. Therefore, identifying potential DNA damaging agents is important for protecting public health. The in vivo alkaline comet assay, which detects DNA damage as strand breaks, is especially relevant for assessing the genotoxic hazards of xenobiotics, as its responses reflect the in vivo absorption, tissue distribution, metabolism and excretion (ADME) of chemicals, as well as DNA repair process. Compared to other in vivo DNA damage assays, the assay is rapid, sensitive, visual and inexpensive, and, by converting oxidative DNA damage into strand breaks using specific repair enzymes, the assay can measure oxidative DNA damage in an efficient and relatively artifact-free manner. Measurement of DNA damage with the comet assay can be performed using both acute and subchronic toxicology study designs, and by integrating the comet assay with other toxicological assessments, the assay addresses animal welfare requirements by making maximum use of animal resources. Another major advantage of the assays is that they only require a small amount of cells, and the cells do not have to be derived from proliferating cell populations. The assays also can be performed with a variety of human samples obtained from clinically or occupationally exposed individuals.

  13. Grape (Vitis vinifera) extracts protect against radiation-induced oxidative stress and DNA damage

    International Nuclear Information System (INIS)

    Singha, Indrani; Das, Subir Kumar; Saxena, S.; Gautam, S.

    2016-01-01

    Ionizing radiation (IR) causes oxidative stress through the overwhelming generation of reactive oxygen species (ROS) in the living cells leading further to the oxidative damage to biomolecules. Grapes (Vitis vinifera) contain several bioactive phytochemicals and are the richest source of antioxidant. In this study, we investigated and compared in vitro antioxidant activity and DNA damage protective property of the grape extracts of four different cultivars, including the Thompson seedless, Flame seedless, Kishmish chorni and Red globe. The activities of ascorbic acid oxidase and catalase significantly (p<0.01) differed among extracts within the same cultivar, while that of peroxidase and polyphenol oxidase did not differ significantly among extracts of any cultivar. In vitro antioxidant activities were assessed by ferric-reducing antioxidant power (FRAP) assay and ABTS. The superoxide radical-scavenging activity was higher in the seed as compared to the skin or pulp of the same cultivar. DNA damage was evaluated in acellular system using pBR322 plasmid relaxation. Grape extract was able to effectively scavenge free radicals in vitro. It could significantly prevent radiation-induced DNA damage. Furthermore, the protective action of grape depends on the source of extract and type of the cultivars. (author)

  14. Effects of a Brussels sprouts extract on oxidative DNA damage and metabolising enzymes in rat liver

    DEFF Research Database (Denmark)

    Sørensen, Mette; Jensen, B.R.; Poulsen, Henrik E.

    2001-01-01

    and catalase activity was also assessed in the kidneys. In order to examine a possible effect of the Brussels sprouts related to oxidative stress, we measured oxidative DNA damage in terms of 7-hydro-8-oxo-2'-deoxyguanosine (8-oxodG) and lipid peroxidation in terms of malondialdehyde (MDA) formation...... on MDA levels were found. The present results support the data obtained in several studies that consumption of cruciferous vegetables is capable of inducing various phase II enzyme systems. However, the observed increase in oxidative DNA damage raises the question of whether greatly increased ingestion...

  15. 4β-Hydroxywithanolide E selectively induces oxidative DNA damage for selective killing of oral cancer cells.

    Science.gov (United States)

    Tang, Jen-Yang; Huang, Hurng-Wern; Wang, Hui-Ru; Chan, Ya-Ching; Haung, Jo-Wen; Shu, Chih-Wen; Wu, Yang-Chang; Chang, Hsueh-Wei

    2018-03-01

    Reactive oxygen species (ROS) induction had been previously reported in 4β-hydroxywithanolide (4βHWE)-induced selective killing of oral cancer cells, but the mechanism involving ROS and the DNA damage effect remain unclear. This study explores the role of ROS and oxidative DNA damage of 4βHWE in the selective killing of oral cancer cells. Changes in cell viability, morphology, ROS, DNA double strand break (DSB) signaling (γH2AX foci in immunofluorescence and DSB signaling in western blotting), and oxidative DNA damage (8-oxo-2'deoxyguanosine [8-oxodG]) were detected in 4βHWE-treated oral cancer (Ca9-22) and/or normal (HGF-1) cells. 4βHWE decreased cell viability, changed cell morphology and induced ROS generation in oral cancer cells rather than oral normal cells, which were recovered by a free radical scavenger N-acetylcysteine (NAC). For immunofluorescence, 4βHWE also accumulated more of the DSB marker, γH2AX foci, in oral cancer cells than in oral normal cells. For western blotting, DSB signaling proteins such as γH2AX and MRN complex (MRE11, RAD50, and NBS1) were overexpressed in 4βHWE-treated oral cancer cells in different concentrations and treatment time. In the formamidopyrimidine-DNA glycolyase (Fpg)-based comet assay and 8-oxodG-based flow cytometry, the 8-oxodG expressions were higher in 4βHWE-treated oral cancer cells than in oral normal cells. All the 4βHWE-induced DSB and oxidative DNA damage to oral cancer cells were recovered by NAC pretreatment. Taken together, the 4βHWE selectively induced DSB and oxidative DNA damage for the ROS-mediated selective killing of oral cancer cells. © 2017 Wiley Periodicals, Inc.

  16. Oxidative DNA damage in vitamin C-supplemented guinea pigs after intratracheal instillation of diesel exhaust particles

    DEFF Research Database (Denmark)

    Moller, P.; Daneshvar, B.; Loft, S.

    2003-01-01

    . The concentrations of ascorbate in liver, lung, and plasma were unaltered by the DEP exposure. The results indicate that in guinea pigs DEP causes oxidative DNA damage rather than bulky DNA adducts in the lung. Guinea pigs, which are similar to humans with respect to vitamin C metabolism, may serve as a new model...... for the study of oxidative damage induced by particulate matter. (C) 2003 Elsevier Science (USA). All rights reserved....

  17. Oxidative damage to DNA by diesel exhaust particle exposure in co-cultures of human lung epithelial cells and macrophages

    DEFF Research Database (Denmark)

    Jantzen, Kim; Roursgaard, Martin; Madsen, Claus Desler

    2012-01-01

    Studies in mono-culture of cells have shown that diesel exhaust particles (DEPs) increase the production of reactive oxygen species (ROS) and oxidative stress-related damage to DNA. However, the level of particle-generated genotoxicity may depend on interplay between different cell types, e.g. lung...... treatment with standard reference DEPs, SRM2975 and SRM1650b. The exposure to DEPs did not affect the colony-forming ability of A549 cells in co-culture with THP-1a cells. The DEPs generated DNA strand breaks and oxidatively damaged DNA, measured using the alkaline comet assay as formamidopyrimidine...... relationship between levels of respiration and ROS production. In conclusion, exposure of mono-cultured cells to DEPs generated oxidative stress to DNA, whereas co-cultures with macrophages had lower levels of oxidatively damaged DNA than A549 epithelial cells....

  18. Elevated levels of urinary markers of oxidatively generated DNA and RNA damage in bipolar disorder

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Poulsen, Henrik Enghusen; Kessing, Lars Vedel

    2015-01-01

    OBJECTIVES: The pathophysiological mechanisms underlying bipolar disorder and its multi-system nature are unclear. Oxidatively generated damage to nucleosides has been demonstrated in metabolic disorders; however, the extent to which this occurs in bipolar disorder in vivo is unknown. We...... investigated oxidatively generated damage to DNA and RNA in patients with bipolar disorder and its relationship with the affective phase compared with healthy control subjects. METHODS: Urinary excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), markers...... of oxidatively generated DNA and RNA damage, respectively, was measured in 37 rapid cycling patients with bipolar disorder and in 40 age- and gender-matched healthy control subjects. Employing a longitudinal design, repeated measurements of both markers were evaluated in various affective phases in patients...

  19. Evaluating Metabolite-Related DNA Oxidation and Adduct Damage from Aryl Amines Using a Microfluidic ECL Array.

    Science.gov (United States)

    Bist, Itti; Bhakta, Snehasis; Jiang, Di; Keyes, Tia E; Martin, Aaron; Forster, Robert J; Rusling, James F

    2017-11-21

    Damage to DNA from the metabolites of drugs and pollutants constitutes a major human toxicity pathway known as genotoxicity. Metabolites can react with metal ions and NADPH to oxidize DNA or participate in S N 2 reactions to form covalently linked adducts with DNA bases. Guanines are the main DNA oxidation sites, and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is the initial product. Here we describe a novel electrochemiluminescent (ECL) microwell array that produces metabolites from test compounds and measures relative rates of DNA oxidation and DNA adduct damage. In this new array, films of DNA, metabolic enzymes, and an ECL metallopolymer or complex assembled in microwells on a pyrolytic graphite wafer are housed in dual microfluidic chambers. As reactant solution passes over the wells, metabolites form and can react with DNA in the films to form DNA adducts. These adducts are detected by ECL from a RuPVP polymer that uses DNA as a coreactant. Aryl amines also combine with Cu 2+ and NADPH to form reactive oxygen species (ROS) that oxidize DNA. The resulting 8-oxodG was detected selectively by ECL-generating bis(2,2'-bipyridine)-(4-(1,10-phenanthrolin-6-yl)-benzoic acid)Os(II). DNA/enzyme films on magnetic beads were oxidized similarly, and 8-oxodG determined by LC/MS/MS enabled array standardization. The array limit of detection for oxidation was 720 8-oxodG per 10 6 nucleobases. For a series of aryl amines, metabolite-generated DNA oxidation and adduct formation turnover rates from the array correlated very well with rodent 1/TD 50 and Comet assay results.

  20. FOXO3 Transcription Factor Is Essential for Protecting Hematopoietic Stem and Progenitor Cells from Oxidative DNA Damage.

    Science.gov (United States)

    Bigarella, Carolina L; Li, Jianfeng; Rimmelé, Pauline; Liang, Raymond; Sobol, Robert W; Ghaffari, Saghi

    2017-02-17

    Accumulation of damaged DNA in hematopoietic stem cells (HSC) is associated with chromosomal abnormalities, genomic instability, and HSC aging and might promote hematological malignancies with age. Despite this, the regulatory pathways implicated in the HSC DNA damage response have not been fully elucidated. One of the sources of DNA damage is reactive oxygen species (ROS) generated by both exogenous and endogenous insults. Balancing ROS levels in HSC requires FOXO3, which is an essential transcription factor for HSC maintenance implicated in HSC aging. Elevated ROS levels result in defective Foxo3 -/- HSC cycling, among many other deficiencies. Here, we show that loss of FOXO3 leads to the accumulation of DNA damage in primitive hematopoietic stem and progenitor cells (HSPC), associated specifically with reduced expression of genes implicated in the repair of oxidative DNA damage. We provide further evidence that Foxo3 -/- HSPC are defective in DNA damage repair. Specifically, we show that the base excision repair pathway, the main pathway utilized for the repair of oxidative DNA damage, is compromised in Foxo3 -/- primitive hematopoietic cells. Treating mice in vivo with N -acetylcysteine reduces ROS levels, rescues HSC cycling defects, and partially mitigates HSPC DNA damage. These results indicate that DNA damage accrued as a result of elevated ROS in Foxo3 -/- mutant HSPC is at least partially reversible. Collectively, our findings suggest that FOXO3 serves as a protector of HSC genomic stability and health. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. DNA damage and defence gene expression after oxidative stress induced by x-rays and diesel exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Risom, Lotte

    2004-07-01

    Particulate air pollution is one the most important environmental health factors for people living in cities. Especially the exhaust particles from traffic are possible causes for cancer and cardiopulmonary diseases. The aim of this thesis was to characterize the health effects of diesel exhaust particles (DEP) by inducing oxidative stress and analyse the underlying mechanisms. Methods for determining oxidative stress, DNA damage, and gene expression were validated and calibrated in lung tissue by studying the dose response relations after ionizing radiation. The study showed the feasibility of partial-body x-ray irradiation as an in vivo model for induction and repair of oxidative DNA damage, of DNA repair enzymes expression, and antioxidant defense genes. A 'nose-only' mouse model for inhalation of ultra-fine particles showed that particles induce oxidative DNA damage in lung tissue and in bronchoalveolar lavage cells. The exposure increased the expression of HO-1 mRNA and oxoguanine DNA glycosylase OGG1 mRNA. The levels of 8-oxodG and OGG1 mRNA were mirror images. Colon and liver were analysed after administration of DEP in the diet with or without increasing doses of sucrose. This study indicated that DEP induces DNA adducts and oxidative stress through formation of DNA strand breaks, DNA repair enzyme expression, apoptosis, and protein oxidisation in colon and liver at relatively low exposure doses. The thesis is based on four published journal articles. (ln)

  2. DNA damage and defence gene expression after oxidative stress induced by x-rays and diesel exhaust particles

    International Nuclear Information System (INIS)

    Risom, Lotte

    2004-01-01

    Particulate air pollution is one the most important environmental health factors for people living in cities. Especially the exhaust particles from traffic are possible causes for cancer and cardiopulmonary diseases. The aim of this thesis was to characterize the health effects of diesel exhaust particles (DEP) by inducing oxidative stress and analyse the underlying mechanisms. Methods for determining oxidative stress, DNA damage, and gene expression were validated and calibrated in lung tissue by studying the dose response relations after ionizing radiation. The study showed the feasibility of partial-body x-ray irradiation as an in vivo model for induction and repair of oxidative DNA damage, of DNA repair enzymes expression, and antioxidant defense genes. A 'nose-only' mouse model for inhalation of ultra-fine particles showed that particles induce oxidative DNA damage in lung tissue and in bronchoalveolar lavage cells. The exposure increased the expression of HO-1 mRNA and oxoguanine DNA glycosylase OGG1 mRNA. The levels of 8-oxodG and OGG1 mRNA were mirror images. Colon and liver were analysed after administration of DEP in the diet with or without increasing doses of sucrose. This study indicated that DEP induces DNA adducts and oxidative stress through formation of DNA strand breaks, DNA repair enzyme expression, apoptosis, and protein oxidisation in colon and liver at relatively low exposure doses. The thesis is based on four published journal articles. (ln)

  3. Oxidatively damaged DNA in animals exposed to particles

    DEFF Research Database (Denmark)

    Møller, Peter; Danielsen, Pernille Høgh; Jantzen, Kim

    2013-01-01

    on optimal methods. The majority of studies have used single intracavitary administration or inhalation with dose rates exceeding the pulmonary overload threshold, resulting in cytotoxicity and inflammation. It is unclear whether this is relevant for the much lower human exposure levels. Still...... not be equivocally determined. Roles of cytotoxicity or inflammation for oxidatively induced DNA damage could not be documented or refuted. Studies on exposure to particles in the gastrointestinal tract showed consistently increased levels of 8-oxo-7,8-dihydroguanine in the liver. Collectively, there is evidence...

  4. Ochratoxin A: induction of (oxidative) DNA damage, cytotoxicity and apoptosis in mammalian cell lines and primary cells

    International Nuclear Information System (INIS)

    Kamp, Hennicke G.; Eisenbrand, Gerhard; Schlatter, Josef; Wuerth, Kirsten; Janzowski, Christine

    2005-01-01

    Ochratoxin A (OTA) is a nephrotoxic/-carcinogenic mycotoxin, produced by several Aspergillus- and Penicillium-strains. Humans are exposed to OTA via food contamination, a causal relationship of OTA to human endemic Balkan nephropathy is still under debate. Since DNA-adducts of OTA or its metabolites could not be identified unambiguously, its carcinogenic effectiveness might be related to secondary effects, such as oxidative cell damage or cell proliferation. In this study, OTA mediated induction of (oxidative) DNA damage, cytotoxicity (necrosis, growth inhibition, apoptosis) and modulation of glutathione were investigated in cell lines (V79, CV-1) and primary rat kidney cells. After 24 h incubation, viability of V79 cells was strongly decreased by OTA concentrations >2.5 μmol/L, whereas CV-1 cells were clearly less sensitive. Strong growth inhibition occurred in both cell lines (IC 50 ∼2 μmol/L). Apoptosis, detected with an immunochemical test and with flow cytometry, was induced by >1 μmol/L OTA. Oxidative DNA damage, detected by comet assay after additional treatment with repair enzymes, was induced in all cell systems already at five-fold lower concentrations. Glutathione in CV-1 cells was depleted after 1 h incubation (>100 μmol/L). In contrast, an increase was measured after 24 h incubation (>0.5 μmol/L). In conclusion, OTA induces oxidative DNA damage at low, not yet cytotoxic concentrations. Oxidative DNA damage might initiate cell transformation eventually in connection with proliferative response following cytotoxic cell death. Both events might represent pivotal factors in the chain of cellular events leading into nephro-carcinogenicity of OTA

  5. Age and metabolic risk factors associated with oxidatively damaged DNA in human peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Løhr, Mille; Jensen, Annie; Eriksen, Louise

    2015-01-01

    Aging is associated with oxidative stress-generated damage to DNA and this could be related to metabolic disturbances. This study investigated the association between levels of oxidatively damaged DNA in peripheral blood mononuclear cells (PBMCs) and metabolic risk factors in 1,019 subjects, aged...... 18-93 years. DNA damage was analyzed as strand breaks by the comet assay and levels of formamidopyrimidine (FPG-) and human 8-oxoguanine DNA glycosylase 1 (hOGG1)-sensitive sites There was an association between age and levels of FPG-sensitive sites for women, but not for men. The same tendency......, cholesterol and glycosylated hemoglobin (HbA1c). In the group of men, there were significant positive associations between alcohol intake, HbA1c and FPG-sensitive sites in multivariate analysis. The levels of metabolic risk factors were positively associated with age, yet only few subjects fulfilled all...

  6. Repair of oxidative DNA base damage in the host genome influences the HIV integration site sequence preference.

    Directory of Open Access Journals (Sweden)

    Geoffrey R Bennett

    Full Text Available Host base excision repair (BER proteins that repair oxidative damage enhance HIV infection. These proteins include the oxidative DNA damage glycosylases 8-oxo-guanine DNA glycosylase (OGG1 and mutY homolog (MYH as well as DNA polymerase beta (Polβ. While deletion of oxidative BER genes leads to decreased HIV infection and integration efficiency, the mechanism remains unknown. One hypothesis is that BER proteins repair the DNA gapped integration intermediate. An alternative hypothesis considers that the most common oxidative DNA base damages occur on guanines. The subtle consensus sequence preference at HIV integration sites includes multiple G:C base pairs surrounding the points of joining. These observations suggest a role for oxidative BER during integration targeting at the nucleotide level. We examined the hypothesis that BER repairs a gapped integration intermediate by measuring HIV infection efficiency in Polβ null cell lines complemented with active site point mutants of Polβ. A DNA synthesis defective mutant, but not a 5'dRP lyase mutant, rescued HIV infection efficiency to wild type levels; this suggested Polβ DNA synthesis activity is not necessary while 5'dRP lyase activity is required for efficient HIV infection. An alternate hypothesis that BER events in the host genome influence HIV integration site selection was examined by sequencing integration sites in OGG1 and MYH null cells. In the absence of these 8-oxo-guanine specific glycosylases the chromatin elements of HIV integration site selection remain the same as in wild type cells. However, the HIV integration site sequence preference at G:C base pairs is altered at several positions in OGG1 and MYH null cells. Inefficient HIV infection in the absence of oxidative BER proteins does not appear related to repair of the gapped integration intermediate; instead oxidative damage repair may participate in HIV integration site preference at the sequence level.

  7. DNA repair is responsible for the presence of oxidatively damaged DNA lesions in urine

    International Nuclear Information System (INIS)

    Cooke, Marcus S.; Evans, Mark D.; Dove, Rosamund; Rozalski, Rafal; Gackowski, Daniel; Siomek, Agnieszka; Lunec, Joseph; Olinski, Ryszard

    2005-01-01

    The repair of oxidatively damaged DNA is integral to the maintenance of genomic stability, and hence prevention of a wide variety of pathological conditions, such as aging, cancer and cardiovascular disease. The ability to non-invasively assess DNA repair may provide information regarding repair pathways, variability in repair capacity, and susceptibility to disease. The development of assays to measure urinary DNA lesions offered this potential, although it rapidly became clear that possible contribution from diet and cell turnover may influence urinary lesion levels. Whilst early studies attempted to address these issues, up until now, much of the data appears conflicting. However, recent work from our laboratories, in which human volunteers were fed highly oxidatively modified 15 N-labelled DNA demonstrates that diet does not appear to contribute to urinary levels of 8-hydroxyguanine and 7,8-dihydro-8-oxo-2'-deoxyguanosine. Furthermore, we propose that a number of literature reports form an argument against a contribution from cell death. Indeed we, and others, have presented evidence, which strongly suggests the involvement of cell death to be minimal. Taken together, these data would appear to rule out various confounding factors, leaving DNA repair pathways as the principal source of urinary purine, if not DNA, lesions enabling such measurements to be used as indicators of repair

  8. An anthocyanin/polyphenolic-rich fruit juice reduces oxidative DNA damage and increases glutathione level in healthy probands.

    Science.gov (United States)

    Weisel, Tamara; Baum, Matthias; Eisenbrand, Gerhard; Dietrich, Helmut; Will, Frank; Stockis, Jean-Pierre; Kulling, Sabine; Rüfer, Corinna; Johannes, Christian; Janzowski, Christine

    2006-04-01

    Oxidative cell damage is involved in the pathogenesis of atherosclerosis, cancer, diabetes and other diseases. Uptake of fruit juice with especially high content of antioxidant flavonoids/polyphenols, might reduce oxidative cell damage. Therefore, an intervention study was performed with a red mixed berry juice [trolox equivalent antioxidative capacity (TEAC): 19.1 mmol/L trolox] and a corresponding polyphenol-depleted juice (polyphenols largely removed, TEAC 2.4 mmol/L trolox), serving as control. After a 3-week run-in period, 18 male probands daily consumed 700 mL juice, and 9 consumed control juice, in a 4-week intervention, followed by a 3-week wash-out. Samples were collected weekly to analyze DNA damage (comet assay), lipid peroxidation (plasma malondialdehyde: HPLC/fluorescence; urinary isoprostanes: GC-MS), blood glutathione (photometrically), DNA-binding activity of nuclear factor-kappaB (ELISA) and plasma carotenoid/alpha-tocopherol levels (HPLC-DAD). During intervention with the fruit juice, a decrease of oxidative DNA damage (p<5x10(-4)) and an increase of reduced glutathione (p<5x10(-4)) and of glutathione status (p<0.05) were observed, which returned to the run-in levels in the subsequent wash-out phase. The other biomarkers were not significantly modulated by the juice supplement. Intervention with the control juice did not result in reduction of oxidative damage. In conclusion, the fruit juice clearly reduces oxidative cell damage in healthy probands.

  9. The Intertwined Roles of DNA Damage and Transcription

    OpenAIRE

    Di Palo, Giacomo

    2016-01-01

    DNA damage and transcription are two interconnected events. Transcription can induce damage and scheduled DNA damage can be required for transcription. Here, we analyzed genome-wide distribution of 8oxodG-marked oxidative DNA damage obtained by OxiDIP-Seq, and we found a correlation with transcription of protein coding genes.

  10. [Occupational hazards, DNA damage, and oxidative stress on exposure to waste anesthetic gases].

    Science.gov (United States)

    Lucio, Lorena M C; Braz, Mariana G; do Nascimento Junior, Paulo; Braz, José Reinaldo C; Braz, Leandro G

    The waste anesthetic gases (WAGs) present in the ambient air of operating rooms (OR), are associated with various occupational hazards. This paper intends to discuss occupational exposure to WAGs and its impact on exposed professionals, with emphasis on genetic damage and oxidative stress. Despite the emergence of safer inhaled anesthetics, occupational exposure to WAGs remains a current concern. Factors related to anesthetic techniques and anesthesia workstations, in addition to the absence of a scavenging system in the OR, contribute to anesthetic pollution. In order to minimize the health risks of exposed professionals, several countries have recommended legislation with maximum exposure limits. However, developing countries still require measurement of WAGs and regulation for occupational exposure to WAGs. WAGs are capable of inducing damage to the genetic material, such as DNA damage assessed using the comet assay and increased frequency of micronucleus in professionals with long-term exposure. Oxidative stress is also associated with WAGs exposure, as it induces lipid peroxidation, oxidative damage in DNA, and impairment of the antioxidant defense system in exposed professionals. The occupational hazards related to WAGs including genotoxicity, mutagenicity and oxidative stress, stand as a public health issue and must be acknowledged by exposed personnel and responsible authorities, especially in developing countries. Thus, it is urgent to stablish maximum safe limits of concentration of WAGs in ORs and educational practices and protocols for exposed professionals. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  11. Effect of complex polyphenols and tannins from red wine on DNA oxidative damage of rat colon mucosa in vivo.

    Science.gov (United States)

    Giovannelli, L; Testa, G; De Filippo, C; Cheynier, V; Clifford, M N; Dolara, P

    2000-10-01

    Dietary polyphenols have been reported to have a variety of biological actions, including anti-carcinogenic, antioxidant and anti-inflammatory activities. In the present study we have evaluated the effect of an oral treatment with complex polyphenols and tannins from red wine and tea on DNA oxidative damage in the rat colon mucosa. Isolated colonocytes were prepared from the colon mucosa of rats treated for ten days with either wine complex polyphenols (57.2 mg/kg/d) or thearubigin (40 mg/kg/d) by oral gavage. Colonocyte oxidative DNA damage was analysed at the single cell level using a modification of the comet assay technique. The results show that wine complex polyphenols and tannins induce a significant decrease (-62% for pyrimidine and -57% for purine oxidation) in basal DNA oxidative damage in colon mucosal cells without affecting the basal level of single-strand breaks. On the other hand, tea polyphenols, namely a crude extract of thearubigin, did not affect either strand breaks or pyrimidine oxidation in colon mucosal cells. Our experiments are the first demonstration that dietary polyphenols can modulate in vivo oxidative damage in the gastrointestinal tract of rodents. These data support the hypothesis that dietary polyphenols might have both a protective and a therapeutic potential in oxidative damage-related pathologies.

  12. Oxidative DNA damage and mammary cell proliferation by alcohol-derived salsolinol.

    Science.gov (United States)

    Murata, Mariko; Midorikawa, Kaoru; Kawanishi, Shosuke

    2013-10-21

    Drinking alcohol is a risk factor for breast cancer. Salsolinol (SAL) is endogenously formed by a condensation reaction of dopamine with acetaldehyde, a major ethanol metabolite, and SAL is detected in blood and urine after alcohol intake. We investigated the possibility that SAL can participate in tumor initiation and promotion by causing DNA damage and cell proliferation, leading to alcohol-associated mammary carcinogenesis. SAL caused oxidative DNA damage including 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), in the presence of transition metal ions, such as Cu(II) and Fe(III)EDTA. Inhibitory effects of scavengers on SAL-induced DNA damage and the electron spin resonance study indicated the involvement of H₂O₂, which is generated via the SAL radical. Experiments on scavengers and site specificity of DNA damage suggested ·OH generation via a Fenton reaction and copper-peroxide complexes in the presence of Fe(III)EDTA and Cu(II), respectively. SAL significantly increased 8-oxodG formation in normal mammary epithelial MCF-10A cells. In addition, SAL induced cell proliferation in estrogen receptor (ER)-negative MCF-10A cells, and the proliferation was inhibited by an antioxidant N-acetylcysteine and an epidermal growth factor receptor (EGFR) inhibitor AG1478, suggesting that reactive oxygen species may participate in the proliferation of MCF-10A cells via EGFR activation. Furthermore, SAL induced proliferation in estrogen-sensitive breast cancer MCF-7 cells, and a surface plasmon resonance sensor revealed that SAL significantly increased the binding activity of ERα to the estrogen response element but not ERβ. In conclusion, SAL-induced DNA damage and cell proliferation may play a role in tumor initiation and promotion of multistage mammary carcinogenesis in relation to drinking alcohol.

  13. Oxidative Stress Measures of Lipid and DNA Damage in Human Tears.

    Science.gov (United States)

    Haworth, Kristina M; Chandler, Heather L

    2017-05-01

    We evaluate feasibility and repeatability of measures for lipid peroxidation and DNA oxidation in human tears, as well as relationships between outcome variables, and compared our findings to previously reported methods of evaluation for ocular sun exposure. A total of 50 volunteers were seen for 2 visits 14 ± 2 days apart. Tear samples were collected from the inferior tear meniscus using a glass microcapillary tube. Oxidative stress biomarkers were quantified using enzyme-linked immunosorbent assay (ELISA): lipid peroxidation by measurement of hexanoyl-lysine (HEL) expression; DNA oxidation by measurement of 8-oxo-2'-deoxyguinosone (8OHdG) expression. Descriptive statistics were generated. Repeatability estimates were made using Bland-Altman plots with mean differences and 95% limits of agreement were calculated. Linear regression was conducted to evaluate relationships between measures. Mean (±SD) values for tear HEL and 8OHdG expression were 17368.02 (±9878.42) nmol/L and 66.13 (±19.99) ng/mL, respectively. Repeatability was found to be acceptable for both HEL and 8OHdG expression. Univariate linear regression supported tear 8OHdG expression and spring season of collection to be predictors of higher tear HEL expression; tear HEL expression was confirmed as a predictor of higher tear 8OHdG expression. We demonstrate feasibility and repeatability of estimating previously unreported tear 8OHdG expression. Seasonal temperature variation and other factors may influence tear lipid peroxidation. Support is demonstrated to suggest lipid damage and DNA damage occur concurrently on the human ocular surface.

  14. Daily grape juice consumption reduces oxidative DNA damage and plasma free radical levels in healthy Koreans

    International Nuclear Information System (INIS)

    Park, Yoo Kyoung; Park, Eunju; Kim, Jung-Shin; Kang, Myung-Hee

    2003-01-01

    Grape contains flavonoids with antioxidant properties which are believed to be protective against various types of cancer. This antioxidative protection is possibly provided by the effective scavenging of reactive oxygen species (ROS), thus defending cellular DNA from oxidative damage and potential mutations. This study of healthy adults tested whether a daily regimen of grape juice supplementation could reduce cellular DNA damage in peripheral lymphocytes and reduce the amount of free radicals released. Sixty-seven healthy volunteers (16 women and 51 men) aged 19-57 years were given 480 ml of grape juice daily for 8 weeks in addition to their normal diet, and blood samples were drawn before and after the intervention. The DNA damage was determined by using the single cell gel (comet) assay with alkaline electrophoresis and was quantified by measuring tail length (TL). Levels of free radicals were determined by reading the lucigenin-perborate ROS generating source, using the Ultra-Weak Chemiluminescence Analyzer System. Grape juice consumption resulted in a significant decrease in lymphocyte DNA damage expressed by TL (before supplementation: 88.75±1.55 μm versus after supplementation: 70.25±1.31 μm; P=0.000 by paired t-test). Additionally, grape juice consumption for 8 weeks reduced the ROS/photon count by 15%, compared to the beginning of the study. The preventive effect of grape juice against DNA damage was simultaneously shown in both sexes. These results indicate that the consumption of grape juice may increase plasma antioxidant capacity, resulting in reduced DNA damage in peripheral lymphocytes achieved at least partially by a reduced release of ROS. Our findings support the hypothesis that polyphenolic compounds contained in grape juice exert cancer-protective effects on lymphocytes, limiting oxidative DNA damage possibly via a decrease in free radical levels

  15. Daily grape juice consumption reduces oxidative DNA damage and plasma free radical levels in healthy Koreans

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yoo Kyoung; Park, Eunju; Kim, Jung-Shin; Kang, Myung-Hee

    2003-08-28

    Grape contains flavonoids with antioxidant properties which are believed to be protective against various types of cancer. This antioxidative protection is possibly provided by the effective scavenging of reactive oxygen species (ROS), thus defending cellular DNA from oxidative damage and potential mutations. This study of healthy adults tested whether a daily regimen of grape juice supplementation could reduce cellular DNA damage in peripheral lymphocytes and reduce the amount of free radicals released. Sixty-seven healthy volunteers (16 women and 51 men) aged 19-57 years were given 480 ml of grape juice daily for 8 weeks in addition to their normal diet, and blood samples were drawn before and after the intervention. The DNA damage was determined by using the single cell gel (comet) assay with alkaline electrophoresis and was quantified by measuring tail length (TL). Levels of free radicals were determined by reading the lucigenin-perborate ROS generating source, using the Ultra-Weak Chemiluminescence Analyzer System. Grape juice consumption resulted in a significant decrease in lymphocyte DNA damage expressed by TL (before supplementation: 88.75{+-}1.55 {mu}m versus after supplementation: 70.25{+-}1.31 {mu}m; P=0.000 by paired t-test). Additionally, grape juice consumption for 8 weeks reduced the ROS/photon count by 15%, compared to the beginning of the study. The preventive effect of grape juice against DNA damage was simultaneously shown in both sexes. These results indicate that the consumption of grape juice may increase plasma antioxidant capacity, resulting in reduced DNA damage in peripheral lymphocytes achieved at least partially by a reduced release of ROS. Our findings support the hypothesis that polyphenolic compounds contained in grape juice exert cancer-protective effects on lymphocytes, limiting oxidative DNA damage possibly via a decrease in free radical levels.

  16. Evaluation of Cassia tora Linn. against oxidative stress-induced DNA and cell membrane damage

    Directory of Open Access Journals (Sweden)

    R Sunil Kumar

    2017-01-01

    Full Text Available Objective: The present study aims to evaluate antioxidants and protective role of Cassia tora Linn. against oxidative stress-induced DNA and cell membrane damage. Materials and Methods: The total and profiles of flavonoids were identified and quantified through reversed-phase high-performance liquid chromatography. In vitro antioxidant activity was determined using standard antioxidant assays. The protective role of C. tora extracts against oxidative stress-induced DNA and cell membrane damage was examined by electrophoretic and scanning electron microscopic studies, respectively. Results: The total flavonoid content of CtEA was 106.8 ± 2.8 mg/g d.w.QE, CtME was 72.4 ± 1.12 mg/g d.w.QE, and CtWE was 30.4 ± 0.8 mg/g d.w.QE. The concentration of flavonoids present in CtEA in decreasing order: quercetin >kaempferol >epicatechin; in CtME: quercetin >rutin >kaempferol; whereas, in CtWE: quercetin >rutin >kaempferol. The CtEA inhibited free radical-induced red blood cell hemolysis and cell membrane morphology better than CtME as confirmed by a scanning electron micrograph. CtEA also showed better protection than CtME and CtWE against free radical-induced DNA damage as confirmed by electrophoresis. Conclusion: C. tora contains flavonoids and inhibits oxidative stress and can be used for many health benefits and pharmacotherapy.

  17. Alpha-Lipoic acid counteracts the promoted oxidative DNA damage in the liver of septic rats

    International Nuclear Information System (INIS)

    Abd-Allah, Adel R.A.

    2006-01-01

    Viral, parasitic infections and chemical carcinogens are among the etiological factors of liver cancer. It seems important to study the initiating and promoting agents to evaluate the etiology and prevention of such life threatening disease. Intestine-derived bacteria product, lipopolysaccharide (LPS), is mainly detoxified by the liver. It has shown to induce a state of oxidative DNA damage is not fully investigated. Increased oxidative DNA damage and rate of cell proliferation may initiate or even promote cancer. In the present work, the capability of LPS to induce 8-hydroxydeoxyguanosine (8-HDG), a specific DNA adduct for oxidative DNA damage, in rat livers is tested. Furthermore, a possible protective effect of alpha lipoic acid (ALA) is also assessed. Investigated parameters are liver contents of glutathione (GSH), lipid peroxides (MDA), nitric oxide (NO) and 8-HDG in the liver-extracted DNA. Serum activities of ALT, AST and GGT as liver-function markers as well as IL2 are assessed. Moreover, liver histology is examined. LPS was given doses of 1, 3, 5, 7 and 9 mg/kg once i.p. while, the rat mortality was examined 24 hours later. ALA was given in doses of 50, 100 and 200 mg/kg once i.p. 3h before LPS is found to be 5mg/kg. LPS increased the level of 8-HDG, MDA and NO in the liver. It also induced acute liver necrosis and inflammatory cell infiltration as shown in liver-histopathology and in the significant increase in the activities of ALT, AST and GGT. LPS increased the serum level of IL2 as well. The dose 200mg/kg of ALA revealed a 100% protection against LPS-induced lethality. It also, prevented the LPS-induced increase in 8-HDG in liver extracted DNA, the liver contents of MDA and NO. ALA also rescued the LPS-induced GSH depletion. It corrected the liver function as shown by the prevention of increases in the activity of ALT, AST and GGT with a remarkable improvement in the liver histology. Moreover, it prevented the increase in serum level of IL2. These

  18. Shape-dependent bactericidal activity of copper oxide nanoparticle mediated by DNA and membrane damage

    International Nuclear Information System (INIS)

    Laha, Dipranjan; Pramanik, Arindam; Laskar, Aparna; Jana, Madhurya; Pramanik, Panchanan; Karmakar, Parimal

    2014-01-01

    Highlights: • Spherical and sheet shaped copper oxide nanoparticles were synthesized. • Physical characterizations of these nanoparticles were done by TEM, DLS, XRD, FTIR. • They showed shape dependent antibacterial activity on different bacterial strain. • They induced both membrane damage and ROS mediated DNA damage in bacteria. - Abstract: In this work, we synthesized spherical and sheet shaped copper oxide nanoparticles and their physical characterizations were done by the X-ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering. The antibacterial activity of these nanoparticles was determined on both gram positive and gram negative bacterial. Spherical shaped copper oxide nanoparticles showed more antibacterial property on gram positive bacteria where as sheet shaped copper oxide nanoparticles are more active on gram negative bacteria. We also demonstrated that copper oxide nanoparticles produced reactive oxygen species in both gram negative and gram positive bacteria. Furthermore, they induced membrane damage as determined by atomic force microscopy and scanning electron microscopy. Thus production of and membrane damage are major mechanisms of the bactericidal activity of these copper oxide nanoparticles. Finally it was concluded that antibacterial activity of nanoparticles depend on physicochemical properties of copper oxide nanoparticles and bacterial strain

  19. Shape-dependent bactericidal activity of copper oxide nanoparticle mediated by DNA and membrane damage

    Energy Technology Data Exchange (ETDEWEB)

    Laha, Dipranjan; Pramanik, Arindam [Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S C Mallick Road, Kolkata 700032 (India); Laskar, Aparna [CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Jana, Madhurya [Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S C Mallick Road, Kolkata 700032 (India); Pramanik, Panchanan [Department of Chemistry, Indian Institute of Technology, Kharagpur 721302 (India); Karmakar, Parimal, E-mail: pkarmakar_28@yahoo.co.in [Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S C Mallick Road, Kolkata 700032 (India)

    2014-11-15

    Highlights: • Spherical and sheet shaped copper oxide nanoparticles were synthesized. • Physical characterizations of these nanoparticles were done by TEM, DLS, XRD, FTIR. • They showed shape dependent antibacterial activity on different bacterial strain. • They induced both membrane damage and ROS mediated DNA damage in bacteria. - Abstract: In this work, we synthesized spherical and sheet shaped copper oxide nanoparticles and their physical characterizations were done by the X-ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering. The antibacterial activity of these nanoparticles was determined on both gram positive and gram negative bacterial. Spherical shaped copper oxide nanoparticles showed more antibacterial property on gram positive bacteria where as sheet shaped copper oxide nanoparticles are more active on gram negative bacteria. We also demonstrated that copper oxide nanoparticles produced reactive oxygen species in both gram negative and gram positive bacteria. Furthermore, they induced membrane damage as determined by atomic force microscopy and scanning electron microscopy. Thus production of and membrane damage are major mechanisms of the bactericidal activity of these copper oxide nanoparticles. Finally it was concluded that antibacterial activity of nanoparticles depend on physicochemical properties of copper oxide nanoparticles and bacterial strain.

  20. Oxidative stress and DNA damage induced by imidacloprid in zebrafish (Danio rerio).

    Science.gov (United States)

    Ge, Weili; Yan, Saihong; Wang, Jinhua; Zhu, Lusheng; Chen, Aimei; Wang, Jun

    2015-02-18

    Imidacloprid is a neonicotinoid insecticide that can have negative effects on nontarget animals. The present study was conducted to assess the toxicity of various imidacloprid doses (0.3, 1.25, and 5 mg/mL) on zebrafish sampled after 7, 14, 21, and 28 days of exposure. The levels of catalase (CAT), superoxide dismutase (SOD), reactive oxygen species (ROS), glutathione-S-transferase (GST), and malondialdehyde (MDA) and the extent of DNA damage were measured to evaluate the toxicity of imidacloprid on zebrafish. SOD and GST activities were noticeably increased during early exposure but were inhibited toward the end of the exposure period. In addition, the CAT levels decreased to the control level following their elevation during early exposure. High concentrations of imidacloprid (1.25 and 5 mg/L) induced excessive ROS production and markedly increased MDA content on the 21st day of exposure. DNA damage was dose- and time-dependent. In conclusion, the present study showed that imidacloprid can induce oxidative stress and DNA damage in zebrafish.

  1. Base excision repair of oxidative DNA damage and association with cancer and aging

    DEFF Research Database (Denmark)

    Maynard, Scott; Schurman, Shepherd H; Harboe, Charlotte

    2009-01-01

    Aging has been associated with damage accumulation in the genome and with increased cancer incidence. Reactive oxygen species (ROS) are produced from endogenous sources, most notably the oxidative metabolism in the mitochondria, and from exogenous sources, such as ionizing radiation. ROS attack DNA...

  2. Green Synthesized Zinc Oxide (ZnO) Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System.

    Science.gov (United States)

    Panda, Kamal K; Golari, Dambaru; Venugopal, A; Achary, V Mohan M; Phaomei, Ganngam; Parinandi, Narasimham L; Sahu, Hrushi K; Panda, Brahma B

    2017-05-18

    Zinc oxide nanoparticles (ZnONP-GS) were synthesised from the precursor zinc acetate (Zn(CH₃COO)₂) through the green route using the milky latex from milk weed ( Calotropis gigantea L. R. Br) by alkaline precipitation. Formation of the ZnONP-GS was monitored by UV-visible spectroscopy followed by characterization and confirmation by energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Both the ZnONP-GS and the commercially available ZnONP-S (Sigma-Aldrich) and cationic Zn 2+ from Zn(CH₃COO)₂ were tested in a dose range of 0-100 mg·L -1 for their potency (i) to induce oxidative stress as measured by the generation reactive oxygen species (ROS: O₂ •- , H₂O₂ and • OH), cell death, and lipid peroxidation; (ii) to modulate the activities of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), guaiacol peroxidase (GPX), and ascorbate peroxidase (APX); and (iii) to cause DNA damage as determined by Comet assay in Lathyrus sativus L. root bioassay system. Antioxidants such as Tiron and dimethylthiourea significantly attenuated the ZnONP-induced oxidative and DNA damage, suggesting the involvement of ROS therein. Our study demonstrated that both ZnONP-GS and ZnONP-S induced oxidative stress and DNA damage to a similar extent but were significantly less potent than Zn 2+ alone.

  3. Evidence that OGG1 glycosylase protects neurons against oxidative DNA damage and cell death under ischemic conditions

    DEFF Research Database (Denmark)

    Liu, Dong; Croteau, Deborah L; Souza-Pinto, Nadja

    2011-01-01

    to ischemic and oxidative stress. After exposure of cultured neurons to oxidative and metabolic stress levels of OGG1 in the nucleus were elevated and mitochondria exhibited fragmentation and increased levels of the mitochondrial fission protein dynamin-related protein 1 (Drp1) and reduced membrane potential......7,8-Dihydro-8-oxoguanine DNA glycosylase (OGG1) is a major DNA glycosylase involved in base-excision repair (BER) of oxidative DNA damage to nuclear and mitochondrial DNA (mtDNA). We used OGG1-deficient (OGG1(-/-)) mice to examine the possible roles of OGG1 in the vulnerability of neurons....... Cortical neurons isolated from OGG1(-/-) mice were more vulnerable to oxidative insults than were OGG1(+/+) neurons, and OGG1(-/-) mice developed larger cortical infarcts and behavioral deficits after permanent middle cerebral artery occlusion compared with OGG1(+/+) mice. Accumulations of oxidative DNA...

  4. Ellipticine induces apoptosis in T-cell lymphoma via oxidative DNA damage

    DEFF Research Database (Denmark)

    Savorani, Cecilia; Manfé, Valentina; Biskup, Edyta

    2015-01-01

    (CTCL), a disease that is progressive, chemoresistant and refractory to treatment. We tested the effect of ellipticine in three cell lines with different p53 status: MyLa2000 (p53(wt/wt)), SeAx ((G245S)p53) and Hut-78 ((R196Stop)p53). Ellipticine caused apoptosis in MyLa2000 and SeAx and restored...... the transcriptional activity of (G245S)p53 in SeAx. However, p53 siRNA knockdown experiments revealed that p53 was not required for ellipticine-induced apoptosis in CTCL. The lipophilic antioxidant α-tocopherol inhibited ellipticine-dependent apoptosis and we linked the apoptotic response to the oxidative DNA damage....... Our results provide evidence that ellipticine-induced apoptosis is exerted through DNA damage and does not require p53 activation in T-cell lymphoma....

  5. Association between Urinary Excretion of Cortisol and Markers of Oxidatively Damaged DNA and RNA in Humans

    DEFF Research Database (Denmark)

    Joergensen, Anders; Broedbaek, Kasper; Weimann, Allan

    2011-01-01

    Chronic psychological stress is associated with accelerated aging, but the underlying biological mechanisms are not known. Prolonged elevations of the stress hormone cortisol is suspected to play a critical role. Through its actions, cortisol may potentially induce oxidatively generated damage...... to cellular constituents such as DNA and RNA, a phenomenon which has been implicated in aging processes. We investigated the relationship between 24 h excretion of urinary cortisol and markers of oxidatively generated DNA and RNA damage, 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydroguanosine......, in a sample of 220 elderly men and women (age 65 - 83 years). We found a robust association between the excretion of cortisol and the oxidation markers (R(2)¿=¿0.15, P...

  6. Vitamin C for DNA damage prevention

    International Nuclear Information System (INIS)

    Sram, Radim J.; Binkova, Blanka; Rossner, Pavel

    2012-01-01

    The ability of vitamin C to affect genetic damage was reviewed in human studies that used molecular epidemiology methods, including analysis of DNA adducts, DNA strand breakage (using the Comet assay), oxidative damage measured as levels of 8-oxo-7,8-dihydroxy-2′-deoxyguanosine (8-oxodG), cytogenetic analysis of chromosomal aberrations and micronuclei, and the induction of DNA repair proteins. The protective effect of vitamin C was observed at plasma levels > 50 μmol/l. Vitamin C supplementation decreased the frequency of chromosomal aberrations in groups with insufficient dietary intake who were occupationally exposed to mutagens, and also decreased the sensitivity to mutagens as assessed using the bleomycin assay. High vitamin C levels in plasma decreased the frequency of genomic translocations in groups exposed to ionizing radiation or c-PAHs in polluted air. The frequency of micronuclei was decreased by vitamin C supplementation in smokers challenged with γ-irradiation, and higher vitamin C levels in plasma counteracted the damage induced by air pollution. The prevalence of DNA adducts inversely correlated with vitamin C levels in groups environmentally exposed to high concentrations of c-PAHs. Increased vitamin C levels decreased DNA strand breakage induced by air pollution. Oxidative damage (8-oxodG levels) was decreased by vitamin C supplementation in groups with plasma levels > 50 μmol/l exposed to PM2.5 and c-PAHs. Modulation of DNA repair by vitamin C supplementation was observed both in poorly nourished subjects and in groups with vitamin C plasma levels > 50 μmol/l exposed to higher concentrations of c-PAHs. It is possible that the impact of vitamin C on DNA damage depends both on background values of vitamin C in the individual as well as on the level of exposure to xenobiotics or oxidative stress.

  7. Vitamin C for DNA damage prevention

    Energy Technology Data Exchange (ETDEWEB)

    Sram, Radim J., E-mail: sram@biomed.cas.cz [Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220 Prague 4 (Czech Republic); Binkova, Blanka; Rossner, Pavel [Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220 Prague 4 (Czech Republic)

    2012-05-01

    The ability of vitamin C to affect genetic damage was reviewed in human studies that used molecular epidemiology methods, including analysis of DNA adducts, DNA strand breakage (using the Comet assay), oxidative damage measured as levels of 8-oxo-7,8-dihydroxy-2 Prime -deoxyguanosine (8-oxodG), cytogenetic analysis of chromosomal aberrations and micronuclei, and the induction of DNA repair proteins. The protective effect of vitamin C was observed at plasma levels > 50 {mu}mol/l. Vitamin C supplementation decreased the frequency of chromosomal aberrations in groups with insufficient dietary intake who were occupationally exposed to mutagens, and also decreased the sensitivity to mutagens as assessed using the bleomycin assay. High vitamin C levels in plasma decreased the frequency of genomic translocations in groups exposed to ionizing radiation or c-PAHs in polluted air. The frequency of micronuclei was decreased by vitamin C supplementation in smokers challenged with {gamma}-irradiation, and higher vitamin C levels in plasma counteracted the damage induced by air pollution. The prevalence of DNA adducts inversely correlated with vitamin C levels in groups environmentally exposed to high concentrations of c-PAHs. Increased vitamin C levels decreased DNA strand breakage induced by air pollution. Oxidative damage (8-oxodG levels) was decreased by vitamin C supplementation in groups with plasma levels > 50 {mu}mol/l exposed to PM2.5 and c-PAHs. Modulation of DNA repair by vitamin C supplementation was observed both in poorly nourished subjects and in groups with vitamin C plasma levels > 50 {mu}mol/l exposed to higher concentrations of c-PAHs. It is possible that the impact of vitamin C on DNA damage depends both on background values of vitamin C in the individual as well as on the level of exposure to xenobiotics or oxidative stress.

  8. Oxidative DNA damage and repair in skeletal muscle of humans exposed to high-altitude hypoxia

    DEFF Research Database (Denmark)

    Lundby, Carsten; Pilegaard, Henriette; van Hall, Gerrit

    2003-01-01

    Recent research suggests that high-altitude hypoxia may serve as a model for prolonged oxidative stress in healthy humans. In this study, we investigated the consequences of prolonged high-altitude hypoxia on the basal level of oxidative damage to nuclear DNA in muscle cells, a major oxygen-consuming...

  9. Hydroxytyrosol Protects against Oxidative DNA Damage in Human Breast Cells

    Directory of Open Access Journals (Sweden)

    José J. Gaforio

    2011-10-01

    Full Text Available Over recent years, several studies have related olive oil ingestion to a low incidence of several diseases, including breast cancer. Hydroxytyrosol and tyrosol are two of the major phenols present in virgin olive oils. Despite the fact that they have been linked to cancer prevention, there is no evidence that clarifies their effect in human breast tumor and non-tumor cells. In the present work, we present hydroxytyrosol and tyrosol’s effects in human breast cell lines. Our results show that hydroxytyrosol acts as a more efficient free radical scavenger than tyrosol, but both fail to affect cell proliferation rates, cell cycle profile or cell apoptosis in human mammary epithelial cells (MCF10A or breast cancer cells (MDA-MB-231 and MCF7. We found that hydroxytyrosol decreases the intracellular reactive oxygen species (ROS level in MCF10A cells but not in MCF7 or MDA-MB-231 cells while very high amounts of tyrosol is needed to decrease the ROS level in MCF10A cells. Interestingly, hydroxytyrosol prevents oxidative DNA damage in the three breast cell lines. Therefore, our data suggest that simple phenol hydroxytyrosol could contribute to a lower incidence of breast cancer in populations that consume virgin olive oil due to its antioxidant activity and its protection against oxidative DNA damage in mammary cells.

  10. The single-strand DNA binding activity of human PC4 preventsmutagenesis and killing by oxidative DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jen-Yeu; Sarker, Altaf Hossain; Cooper, Priscilla K.; Volkert, Michael R.

    2004-02-01

    Human positive cofactor 4 (PC4) is a transcriptional coactivator with a highly conserved single-strand DNA (ssDNA) binding domain of unknown function. We identified PC4 as a suppressor of the oxidative mutator phenotype of the Escherichia coli fpg mutY mutant and demonstrate that this suppression requires its ssDNA binding activity. Yeast mutants lacking their PC4 ortholog Sub1 are sensitive to hydrogen peroxide and exhibit spontaneous and peroxide induced hypermutability. PC4 expression suppresses the peroxide sensitivity of the yeast sub l{Delta} mutant, suggesting that the human protein has a similar function. A role for yeast and human proteins in DNA repair is suggested by the demonstration that Sub1 acts in a peroxide-resistance pathway involving Rad2 and by the physical interaction of PC4 with the human Rad2 homolog XPG. We show XPG recruits PC4 to a bubble-containing DNA substrate with resulting displacement of XPG and formation of a PC4-DNA complex. We discuss the possible requirement for PC4 in either global or transcription-coupled repair of oxidative DNA damage to mediate the release of XPG bound to its substrate.

  11. Effects of environmental pollution on endogenous oxidative DNA damage in humans

    Czech Academy of Sciences Publication Activity Database

    Singh, R.; Kaur, B.; Kalina, I.; Popov, T. A.; Georgieva, T.; Garte, S.; Binková, Blanka; Šrám, Radim; Taioli, E.; Farmer, P. B.

    2007-01-01

    Roč. 620, - (2007), s. 71-82 ISSN 0027-5107 Grant - others:EU(NO) 2000 -00091; EU(NO) G0100873 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK ; R - rámcový projekt EK Keywords : oxidative DNA damage * polycyclic aromatic hydrocarbons * -oxo-deoxyguanosine Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

  12. Systemic oxidatively generated DNA/RNA damage in clinical depression

    DEFF Research Database (Denmark)

    Jorgensen, Anders; Krogh, Jesper; Miskowiak, Kamilla

    2013-01-01

    oxidatively generated DNA and RNA damage, 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), respectively, were determined in healthy controls (N=28), moderately depressed, non-medicated patients (N=26) and severely depressed patients eligible for electroconvulsive therapy...... for trend=0.004). The 8-oxoGuo excretion was further increased after clinically effective ECT compared with pre-ECT values (P=0.006). There were no differences in 8-oxodG excretion between the groups or pre- vs. post-ECT. LIMITATIONS: Small sample size and the inclusion of both unipolar and bipolar patients...

  13. Green Synthesized Zinc Oxide (ZnO Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System

    Directory of Open Access Journals (Sweden)

    Kamal K. Panda

    2017-05-01

    Full Text Available Zinc oxide nanoparticles (ZnONP-GS were synthesised from the precursor zinc acetate (Zn(CH3COO2 through the green route using the milky latex from milk weed (Calotropis gigantea L. R. Br by alkaline precipitation. Formation of the ZnONP-GS was monitored by UV-visible spectroscopy followed by characterization and confirmation by energy-dispersive X-ray spectroscopy (EDX, transmission electron microscopy (TEM, and X-ray diffraction (XRD. Both the ZnONP-GS and the commercially available ZnONP-S (Sigma-Aldrich and cationic Zn2+ from Zn(CH3COO2 were tested in a dose range of 0–100 mg·L−1 for their potency (i to induce oxidative stress as measured by the generation reactive oxygen species (ROS: O2•−, H2O2 and •OH, cell death, and lipid peroxidation; (ii to modulate the activities of antioxidant enzymes: catalase (CAT, superoxide dismutase (SOD, guaiacol peroxidase (GPX, and ascorbate peroxidase (APX; and (iii to cause DNA damage as determined by Comet assay in Lathyrus sativus L. root bioassay system. Antioxidants such as Tiron and dimethylthiourea significantly attenuated the ZnONP-induced oxidative and DNA damage, suggesting the involvement of ROS therein. Our study demonstrated that both ZnONP-GS and ZnONP-S induced oxidative stress and DNA damage to a similar extent but were significantly less potent than Zn2+ alone.

  14. Parental exposure to the herbicide diuron results in oxidative DNA damage to germinal cells of the Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Barranger, Audrey; Heude-Berthelin, Clothilde; Rouxel, Julien; Adeline, Béatrice; Benabdelmouna, Abdellah; Burgeot, Thierry; Akcha, Farida

    2016-02-01

    Chemical pollution by pesticides has been identified as a possible contributing factor to the massive mortality outbreaks observed in Crassostrea gigas for several years. A previous study demonstrated the vertical transmission of DNA damage by subjecting oyster genitors to the herbicide diuron at environmental concentrations during gametogenesis. This trans-generational effect occurs through damage to genitor-exposed gametes, as measured by the comet-assay. The presence of DNA damage in gametes could be linked to the formation of DNA damage in other germ cells. In order to explore this question, the levels and cell distribution of the oxidized base lesion 8-oxodGuo were studied in the gonads of exposed genitors. High-performance liquid chromatography coupled with UV and electrochemical detection analysis showed an increase in 8-oxodGuo levels in both male and female gonads after exposure to diuron. Immunohistochemistry analysis showed the presence of 8-oxodGuo at all stages of male germ cells, from early to mature stages. Conversely, the oxidized base was only present in early germ cell stages in female gonads. These results indicate that male and female genitors underwent oxidative stress following exposure to diuron, resulting in DNA oxidation in both early germ cells and gametes, such as spermatozoa, which could explain the transmission of diuron-induced DNA damage to offspring. Furthermore, immunostaining of early germ cells seems indicates that damages caused by exposure to diuron on germ line not only affect the current sexual cycle but also could affect future gametogenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Pulmonary dysfunctions, oxidative stress and DNA damage in brick kiln workers.

    Science.gov (United States)

    Kaushik, R; Khaliq, F; Subramaneyaan, M; Ahmed, R S

    2012-11-01

    Brick kilns in the suburban areas in developing countries pose a big threat to the environment and hence the health of their workers and people residing around them. The present study was planned to assess the lung functions, oxidative stress parameters and DNA damage in brick kiln workers. A total of 31 male subjects working in brick kiln, and 32 age, sex and socioeconomic status matched controls were included in the study. The lung volumes, capacities and flow rates, namely, forced expiratory volume in first second (FEV(1)), forced vital capacity (FVC), FEV(1)/FVC, expiratory reserve volume, inspiratory capacity (IC), maximal expiratory flow when 50% of FVC is remaining to be expired, maximum voluntary ventilation, peak expiratory flow rate and vital capacity were significantly decreased in the brick kiln workers. Increased oxidative stress as evidenced by increased malonedialdehyde levels and reduced glutathione content, glutathione S-transferase activity and ferric reducing ability of plasma were observed in the study group when compared with controls. Our results indicate a significant correlation between oxidative stress parameters and pulmonary dysfunction, which may be due to silica-induced oxidative stress and resulting lung damage.

  16. Replication stress and oxidative damage contribute to aberrant constitutive activation of DNA damage signalling in human gliomas

    DEFF Research Database (Denmark)

    Bartkova, J; Hamerlik, P; Stockhausen, Marie

    2010-01-01

    damage signalling in low- and high-grade human gliomas, and analyze the sources of such endogenous genotoxic stress. Based on analyses of human glioblastoma multiforme (GBM) cell lines, normal astrocytes and clinical specimens from grade II astrocytomas (n=41) and grade IV GBM (n=60), we conclude...... that the DDR machinery is constitutively activated in gliomas, as documented by phosphorylated histone H2AX (gammaH2AX), activation of the ATM-Chk2-p53 pathway, 53BP1 foci and other markers. Oxidative DNA damage (8-oxoguanine) was high in some GBM cell lines and many GBM tumors, while it was low in normal...... brain and grade II astrocytomas, despite the degree of DDR activation was higher in grade II tumors. Markers indicative of ongoing DNA replication stress (Chk1 activation, Rad17 phosphorylation, replication protein A foci and single-stranded DNA) were present in GBM cells under high- or low...

  17. Micronutrients intake associated with DNA damage assessed by in a human biomonitoring study

    Directory of Open Access Journals (Sweden)

    Carina Ladeira

    2015-05-01

    Retinol was positively correlated with oxidative DNA damage in controls. The study by van Helden et al. (2009 demonstrated that vitamin A enhances OH radical formation in the Fenton reaction, showing that vitamin A can act as pro-oxidant or antioxidant, depending on the type of radicals involved, and may lead to DNA oxidative damage (Alakhras et al., 2011. Azqueta & Collins (2012 clearly distinguished between effects of vitamin A, pro-vitamin A carotenoids, and non-vitamin A carotenoids; being the latter group almost invariably reported to protect against DNA damage, whether endogenous or induced by exogenous agents, the pro-vitamin A carotenoids show a wider spectrum of effects, sometimes protecting and sometimes enhancing DNA damage. Vitamin E was found to be positively correlated with % DNA in tail. Watters et al. (2007 also found a positive association of vitamin E and oxidative DNA damage in a healthy, non-smoking population of young adults. A possible explanation for this result stems from some evidence that in the presence of copper or in smokers with a fat rich diet, vitamin E can act as a strong pro-oxidant, nevertheless it remains an unexpected result. Results found a positive correlation between iron and % DNA in tail, meaning that higher intake of iron associates with higher DNA damage. Oxidative lesions, and more specifically 8-OHdG, is one of the most prevalent lesions induced by iron containing substances (Prá et al., 2012, however the FPG biomarker was not statistically associated with iron. There is sound evidence that iron deficiency increases genome instability, among other mechanisms, by impairing enzymes involved in antioxidant and nuclei acid metabolism (Prá et al., 2012. Results presented herein found that the amount of calories ingested was negatively correlated with both biomarkers assessed by comet assay. This was somewhat unexpected, as calories restriction reduces metabolic rate and oxidative stress, meaning that lower calories

  18. Oxidative DNA Damage in Neurons: Implication of Ku in Neuronal Homeostasis and Survival

    Directory of Open Access Journals (Sweden)

    Daniela De Zio

    2012-01-01

    Full Text Available Oxidative DNA damage is produced by reactive oxygen species (ROS which are generated by exogenous and endogenous sources and continuously challenge the cell. One of the most severe DNA lesions is the double-strand break (DSB, which is mainly repaired by nonhomologous end joining (NHEJ pathway in mammals. NHEJ directly joins the broken ends, without using the homologous template. Ku70/86 heterodimer, also known as Ku, is the first component of NHEJ as it directly binds DNA and recruits other NHEJ factors to promote the repair of the broken ends. Neurons are particularly metabolically active, displaying high rates of transcription and translation, which are associated with high metabolic and mitochondrial activity as well as oxygen consumption. In such a way, excessive oxygen radicals can be generated and constantly attack DNA, thereby producing several lesions. This condition, together with defective DNA repair systems, can lead to a high accumulation of DNA damage resulting in neurodegenerative processes and defects in neurodevelopment. In light of recent findings, in this paper, we will discuss the possible implication of Ku in neurodevelopment and in mediating the DNA repair dysfunction observed in certain neurodegenerations.

  19. Evaluation of oxidative DNA damage promoted by storage in sperm from sex-reversed rainbow trout.

    Science.gov (United States)

    Pérez-Cerezales, S; Martínez-Páramo, S; Cabrita, E; Martínez-Pastor, F; de Paz, P; Herráez, M P

    2009-03-01

    Short-term storage and cryopreservation of sperm are two common procedures in aquaculture, used for routine practices in artificial insemination reproduction and gene banking, respectively. Nevertheless, both procedures cause injuries affecting sperm motility, viability, cell structure and DNA stability, which diminish reproductive success. DNA modification is considered extremely important, especially when sperm storage is carried out with gene banking purposes. DNA damage caused by sperm storage is not well characterized and previous studies have reported simple and double strand breaks that have been attributed to oxidative events promoted by the generation of free radicals during storage. The objective of this study was to reveal DNA fragmentation and to explore the presence of oxidized bases that could be produced by oxidative events during short-term storage and cryopreservation in sex-reversed rainbow trout (Oncorhynchus mykiss) spermatozoa. Sperm from six males was analyzed separately. Different aliquots of the samples were stored 2h (fresh) or 5 days at 4 degrees C or were cryopreserved. Then spermatozoa were analyzed using the Comet assay, as well as combining this method with digestion with two endonucleases from Escherichia coli (Endonuclease III, that cut in oxidized cytosines, and FPG, cutting in oxidized guanosines). Both storage procedures yielded DNA fragmentation, but only short-term storage oxidative events were clearly detected, showing that oxidative processes affect guanosines rather than cytosines. Cryopreservation increases DNA fragmentation but the presence of oxidized bases was not noticed, suggesting that mechanisms other than oxidative stress could be involved in DNA fragmentation promoted by freezing.

  20. Fructose-Rich Diet Affects Mitochondrial DNA Damage and Repair in Rats.

    Science.gov (United States)

    Cioffi, Federica; Senese, Rosalba; Lasala, Pasquale; Ziello, Angela; Mazzoli, Arianna; Crescenzo, Raffaella; Liverini, Giovanna; Lanni, Antonia; Goglia, Fernando; Iossa, Susanna

    2017-03-24

    Evidence indicates that many forms of fructose-induced metabolic disturbance are associated with oxidative stress and mitochondrial dysfunction. Mitochondria are prominent targets of oxidative damage; however, it is not clear whether mitochondrial DNA (mtDNA) damage and/or its lack of repair are events involved in metabolic disease resulting from a fructose-rich diet. In the present study, we evaluated the degree of oxidative damage to liver mtDNA and its repair, in addition to the state of oxidative stress and antioxidant defense in the liver of rats fed a high-fructose diet. We used male rats feeding on a high-fructose or control diet for eight weeks. Our results showed an increase in mtDNA damage in the liver of rats fed a high-fructose diet and this damage, as evaluated by the expression of DNA polymerase γ, was not repaired; in addition, the mtDNA copy number was found to be significantly reduced. A reduction in the mtDNA copy number is indicative of impaired mitochondrial biogenesis, as is the finding of a reduction in the expression of genes involved in mitochondrial biogenesis. In conclusion, a fructose-rich diet leads to mitochondrial and mtDNA damage, which consequently may have a role in liver dysfunction and metabolic diseases.

  1. DNA Damage, Repair, and Cancer Metabolism

    Science.gov (United States)

    Turgeon, Marc-Olivier; Perry, Nicholas J. S.; Poulogiannis, George

    2018-01-01

    Although there has been a renewed interest in the field of cancer metabolism in the last decade, the link between metabolism and DNA damage/DNA repair in cancer has yet to be appreciably explored. In this review, we examine the evidence connecting DNA damage and repair mechanisms with cell metabolism through three principal links. (1) Regulation of methyl- and acetyl-group donors through different metabolic pathways can impact DNA folding and remodeling, an essential part of accurate double strand break repair. (2) Glutamine, aspartate, and other nutrients are essential for de novo nucleotide synthesis, which dictates the availability of the nucleotide pool, and thereby influences DNA repair and replication. (3) Reactive oxygen species, which can increase oxidative DNA damage and hence the load of the DNA-repair machinery, are regulated through different metabolic pathways. Interestingly, while metabolism affects DNA repair, DNA damage can also induce metabolic rewiring. Activation of the DNA damage response (DDR) triggers an increase in nucleotide synthesis and anabolic glucose metabolism, while also reducing glutamine anaplerosis. Furthermore, mutations in genes involved in the DDR and DNA repair also lead to metabolic rewiring. Links between cancer metabolism and DNA damage/DNA repair are increasingly apparent, yielding opportunities to investigate the mechanistic basis behind potential metabolic vulnerabilities of a substantial fraction of tumors. PMID:29459886

  2. Radiation-induced oxidative damage to the DNA-binding domain of the lactose repressor

    Czech Academy of Sciences Publication Activity Database

    Gillard, N.; Goffinont, S.; Buré, C.; Davídková, Marie; Maurizot, J. C.; Cadene, M.; Spotheim-Maurizot, M.

    2007-01-01

    Roč. 403, part 3 (2007), s. 463-472 ISSN 0264-6021 R&D Projects: GA MŠk 1P05OC085 Institutional research plan: CEZ:AV0Z10480505 Keywords : ionizing radiation * oxidative damage * DNA binding domain * lac repressor Subject RIV: CE - Biochemistry Impact factor: 4.009, year: 2007

  3. ATM directs DNA damage responses and proteostasis via genetically separable pathways.

    Science.gov (United States)

    Lee, Ji-Hoon; Mand, Michael R; Kao, Chung-Hsuan; Zhou, Yi; Ryu, Seung W; Richards, Alicia L; Coon, Joshua J; Paull, Tanya T

    2018-01-09

    The protein kinase ATM is a master regulator of the DNA damage response but also responds directly to oxidative stress. Loss of ATM causes ataxia telangiectasia, a neurodegenerative disorder with pleiotropic symptoms that include cerebellar dysfunction, cancer, diabetes, and premature aging. We genetically separated the activation of ATM by DNA damage from that by oxidative stress using separation-of-function mutations. We found that deficient activation of ATM by the Mre11-Rad50-Nbs1 complex and DNA double-strand breaks resulted in loss of cell viability, checkpoint activation, and DNA end resection in response to DNA damage. In contrast, loss of oxidative activation of ATM had minimal effects on DNA damage-related outcomes but blocked ATM-mediated initiation of checkpoint responses after oxidative stress and resulted in deficiencies in mitochondrial function and autophagy. In addition, expression of a variant ATM incapable of activation by oxidative stress resulted in widespread protein aggregation. These results indicate a direct relationship between the mechanism of ATM activation and its effects on cellular metabolism and DNA damage responses in human cells and implicate ATM in the control of protein homeostasis. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  4. Clustered DNA damages induced in isolated DNA and in human cells by low doses of ionizing radiation

    Science.gov (United States)

    Sutherland, B. M.; Bennett, P. V.; Sidorkina, O.; Laval, J.; Lowenstein, D. I. (Principal Investigator)

    2000-01-01

    Clustered DNA damages-two or more closely spaced damages (strand breaks, abasic sites, or oxidized bases) on opposing strands-are suspects as critical lesions producing lethal and mutagenic effects of ionizing radiation. However, as a result of the lack of methods for measuring damage clusters induced by ionizing radiation in genomic DNA, neither the frequencies of their production by physiological doses of radiation, nor their repairability, nor their biological effects are known. On the basis of methods that we developed for quantitating damages in large DNAs, we have devised and validated a way of measuring ionizing radiation-induced clustered lesions in genomic DNA, including DNA from human cells. DNA is treated with an endonuclease that induces a single-strand cleavage at an oxidized base or abasic site. If there are two closely spaced damages on opposing strands, such cleavage will reduce the size of the DNA on a nondenaturing gel. We show that ionizing radiation does induce clustered DNA damages containing abasic sites, oxidized purines, or oxidized pyrimidines. Further, the frequency of each of these cluster classes is comparable to that of frank double-strand breaks; among all complex damages induced by ionizing radiation, double-strand breaks are only about 20%, with other clustered damage constituting some 80%. We also show that even low doses (0.1-1 Gy) of high linear energy transfer ionizing radiation induce clustered damages in human cells.

  5. The 2100MHz radiofrequency radiation of a 3G-mobile phone and the DNA oxidative damage in brain.

    Science.gov (United States)

    Sahin, Duygu; Ozgur, Elcin; Guler, Goknur; Tomruk, Arın; Unlu, Ilhan; Sepici-Dinçel, Aylin; Seyhan, Nesrin

    2016-09-01

    We aimed to evaluate the effect of 2100MHz radiofrequency radiation emitted by a generator, simulating a 3G-mobile phone on the brain of rats during 10 and 40 days of exposure. The female rats were randomly divided into four groups. Group I; exposed to 3G modulated 2100MHz RFR signal for 6h/day, 5 consecutive days/wk for 2 weeks, group II; control 10 days, were kept in an inactive exposure set-up for 6h/day, 5 consecutive days/wk for 2 weeks, group III; exposed to 3G modulated 2100MHz RFR signal for 6h/day, 5 consecutive days/wk for 8 weeks and group IV; control 40 days, were kept in an inactive exposure set-up for 6h/day, 5 consecutive days/wk for 8 weeks. After the genomic DNA content of brain was extracted, oxidative DNA damage (8-hydroxy-2'deoxyguanosine, pg/mL) and malondialdehyde (MDA, nmoL/g tissue) levels were determined. Our main finding was the increased oxidative DNA damage to brain after 10 days of exposure with the decreased oxidative DNA damage following 40 days of exposure compared to their control groups. Besides decreased lipid peroxidation end product, MDA, was observed after 40 days of exposure. The measured decreased quantities of damage during the 40 days of exposure could be the means of adapted and increased DNA repair mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Magnetic Hyperthermia and Oxidative Damage to DNA of Human Hepatocarcinoma Cells.

    Science.gov (United States)

    Cellai, Filippo; Munnia, Armelle; Viti, Jessica; Doumett, Saer; Ravagli, Costanza; Ceni, Elisabetta; Mello, Tommaso; Polvani, Simone; Giese, Roger W; Baldi, Giovanni; Galli, Andrea; Peluso, Marco E M

    2017-04-29

    Nanotechnology is addressing major urgent needs for cancer treatment. We conducted a study to compare the frequency of 3-(2-deoxy-β-d-erythro-pentafuranosyl)pyrimido[1,2-α]purin-10(3 H )-one deoxyguanosine (M₁dG) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) adducts, biomarkers of oxidative stress and/or lipid peroxidation, on human hepatocarcinoma HepG2 cells exposed to increasing levels of Fe₃O₄-nanoparticles (NPs) versus untreated cells at different lengths of incubations, and in the presence of increasing exposures to an alternating magnetic field (AMF) of 186 kHz using 32 P-postlabeling. The levels of oxidative damage tended to increase significantly after ≥24 h of incubations compared to controls. The oxidative DNA damage tended to reach a steady-state after treatment with 60 μg/mL of Fe₃O₄-NPs. Significant dose-response relationships were observed. A greater adduct production was observed after magnetic hyperthermia, with the highest amounts of oxidative lesions after 40 min exposure to AMF. The effects of magnetic hyperthermia were significantly increased with exposure and incubation times. Most important, the levels of oxidative lesions in AMF exposed NP treated cells were up to 20-fold greater relative to those observed in nonexposed NP treated cells. Generation of oxidative lesions may be a mechanism by which magnetic hyperthermia induces cancer cell death.

  7. Cadmium Chloride Induces DNA Damage and Apoptosis of Human Liver Carcinoma Cells via Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Anthony Skipper

    2016-01-01

    Full Text Available Cadmium is a heavy metal that has been shown to cause its toxicity in humans and animals. Many documented studies have shown that cadmium produces various genotoxic effects such as DNA damage and chromosomal aberrations. Ailments such as bone disease, renal damage, and several forms of cancer are attributed to overexposure to cadmium.  Although there have been numerous studies examining the effects of cadmium in animal models and a few case studies involving communities where cadmium contamination has occurred, its molecular mechanisms of action are not fully elucidated. In this research, we hypothesized that oxidative stress plays a key role in cadmium chloride-induced toxicity, DNA damage, and apoptosis of human liver carcinoma (HepG2 cells. To test our hypothesis, cell viability was determined by MTT assay. Lipid hydroperoxide content stress was estimated by lipid peroxidation assay. Genotoxic damage was tested by the means of alkaline single cell gel electrophoresis (Comet assay. Cell apoptosis was measured by flow cytometry assessment (Annexin-V/PI assay. The result of MTT assay indicated that cadmium chloride induces toxicity to HepG2 cells in a concentration-dependent manner, showing a 48 hr-LD50 of 3.6 µg/mL. Data generated from lipid peroxidation assay resulted in a significant (p < 0.05 increase of hydroperoxide production, specifically at the highest concentration tested. Data obtained from the Comet assay indicated that cadmium chloride causes DNA damage in HepG2 cells in a concentration-dependent manner. A strong concentration-response relationship (p < 0.05 was recorded between annexin V positive cells and cadmium chloride exposure. In summary, these in vitro studies provide clear evidence that cadmium chloride induces oxidative stress, DNA damage, and programmed cell death in human liver carcinoma (HepG2 cells.

  8. GSTP1 Loss results in accumulation of oxidative DNA base damage and promotes prostate cancer cell survival following exposure to protracted oxidative stress.

    Science.gov (United States)

    Mian, Omar Y; Khattab, Mohamed H; Hedayati, Mohammad; Coulter, Jonathan; Abubaker-Sharif, Budri; Schwaninger, Julie M; Veeraswamy, Ravi K; Brooks, James D; Hopkins, Lisa; Shinohara, Debika Biswal; Cornblatt, Brian; Nelson, William G; Yegnasubramanian, Srinivasan; DeWeese, Theodore L

    2016-02-01

    Epigenetic silencing of glutathione S-transferase π (GSTP1) is a hallmark of transformation from normal prostatic epithelium to adenocarcinoma of the prostate. The functional significance of this loss is incompletely understood. The present study explores the effects of restored GSTP1 expression on glutathione levels, accumulation of oxidative DNA damage, and prostate cancer cell survival following oxidative stress induced by protracted, low dose rate ionizing radiation (LDR). GSTP1 protein expression was stably restored in LNCaP prostate cancer cells. The effect of GSTP1 restoration on protracted LDR-induced oxidative DNA damage was measured by GC-MS quantitation of modified bases. Reduced and oxidized glutathione levels were measured in control and GSTP1 expressing populations. Clonogenic survival studies of GSTP1- transfected LNCaP cells after exposure to protracted LDR were performed. Global gene expression profiling and pathway analysis were performed. GSTP1 expressing cells accumulated less oxidized DNA base damage and exhibited decreased survival compared to control LNCaP-Neo cells following oxidative injury induced by protracted LDR. Restoration of GSTP1 expression resulted in changes in modified glutathione levels that correlated with GSTP1 protein levels in response to protracted LDR-induced oxidative stress. Survival differences were not attributable to depletion of cellular glutathione stores. Gene expression profiling and pathway analysis following GSTP1 restoration suggests this protein plays a key role in regulating prostate cancer cell survival. The ubiquitous epigenetic silencing of GSTP1 in prostate cancer results in enhanced survival and accumulation of potentially promutagenic DNA adducts following exposure of cells to protracted oxidative injury suggesting a protective, anti-neoplastic function of GSTP1. The present work provides mechanistic backing to the tumor suppressor function of GSTP1 and its role in prostate carcinogenesis. © 2015

  9. Echinacoside Induces Apoptosis in Human SW480 Colorectal Cancer Cells by Induction of Oxidative DNA Damages

    Directory of Open Access Journals (Sweden)

    Liwei Dong

    2015-06-01

    Full Text Available Echinacoside is a natural compound with potent reactive oxygen species (ROS-scavenging and anti-oxidative bioactivities, which protect cells from oxidative damages. As cancer cells are often under intense oxidative stress, we therefore tested if Echinacoside treatment would promote cancer development. Surprisingly, we found that Echinacoside significantly inhibited the growth and proliferation of a panel of cancer cell lines. Treatment of the human SW480 cancer cells with Echinacoside resulted in marked apoptosis and cell cycle arrest, together with a significant increase in active caspase 3 and cleaved PARP, and upregulation of the G1/S-CDK blocker CDKN1B (p21. Interestingly, immunocytochemistry examination of drug-treated cancer cells revealed that Echinacoside caused a significant increase of intracellular oxidized guanine, 8-oxoG, and dramatic upregulation of the double-strand DNA break (DSB-binding protein 53BP1, suggesting that Echinacoside induced cell cycle arrest and apoptosis in SW480 cancer cells via induction of oxidative DNA damages. These results establish Echinacoside as a novel chemical scaffold for development of anticancer drugs.

  10. Oxidative DNA damage in bone marrow cells of patients with low-risk myelodysplastic syndrome

    Czech Academy of Sciences Publication Activity Database

    Novotná, Božena; Bagryantseva, Yana; Šišková, M.; Neuwirtová, R.

    2009-01-01

    Roč. 33, č. 2 (2009), s. 340-343 ISSN 0145-2126 R&D Projects: GA MZd NR8265 Institutional research plan: CEZ:AV0Z50390512 Keywords : Myelodysplastic syndrome * Refractory anemia * Oxidative DNA damage Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.358, year: 2009

  11. Accumulation of premutagenic DNA lesions in mice defective in removal of oxidative base damage

    Science.gov (United States)

    Klungland, Arne; Rosewell, Ian; Hollenbach, Stephan; Larsen, Elisabeth; Daly, Graham; Epe, Bernd; Seeberg, Erling; Lindahl, Tomas; Barnes, Deborah E.

    1999-01-01

    DNA damage generated by oxidant byproducts of cellular metabolism has been proposed as a key factor in cancer and aging. Oxygen free radicals cause predominantly base damage in DNA, and the most frequent mutagenic base lesion is 7,8-dihydro-8-oxoguanine (8-oxoG). This altered base can pair with A as well as C residues, leading to a greatly increased frequency of spontaneous G·C→T·A transversion mutations in repair-deficient bacterial and yeast cells. Eukaryotic cells use a specific DNA glycosylase, the product of the OGG1 gene, to excise 8-oxoG from DNA. To assess the role of the mammalian enzyme in repair of DNA damage and prevention of carcinogenesis, we have generated homozygous ogg1−/− null mice. These animals are viable but accumulate abnormal levels of 8-oxoG in their genomes. Despite this increase in potentially miscoding DNA lesions, OGG1-deficient mice exhibit only a moderately, but significantly, elevated spontaneous mutation rate in nonproliferative tissues, do not develop malignancies, and show no marked pathological changes. Extracts of ogg1 null mouse tissues cannot excise the damaged base, but there is significant slow removal in vivo from proliferating cells. These findings suggest that in the absence of the DNA glycosylase, and in apparent contrast to bacterial and yeast cells, an alternative repair pathway functions to minimize the effects of an increased load of 8-oxoG in the genome and maintain a low endogenous mutation frequency. PMID:10557315

  12. Oxidatively damaged DNA in rats exposed by oral gavage to C60 fullerenes and single-walled carbon nanotubes

    DEFF Research Database (Denmark)

    Folkmann, Janne K; Risom, Lotte; Jacobsen, Nicklas R

    2009-01-01

    BACKGROUND: C60 fullerenes and single-walled carbon nanotubes (SWCNT) are projected to be used in medicine and consumer products with potential human exposure. The hazardous effects of these particles are expected to involve oxidative stress with generation of oxidatively damaged DNA that might...... be the initiating event in the development of cancer. OBJECTIVE: In this study we investigated the effect of a single oral administration of C60 fullerenes and SWCNT. METHODS: We measured the level of oxidative damage to DNA as the premutagenic 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in the colon mucosa...... of genotoxicity, whereas corn oil per se generated more genotoxicity than the particles. Although there was increased mRNA expression of 8-oxoguanine DNA glycosylase in the liver of C60 fullerene-treated rats, we found no significant increase in repair activity. CONCLUSIONS: Oral exposure to low doses of C60...

  13. Metallothionein blocks oxidative DNA damage induced by acute inorganic arsenic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Wei, E-mail: qu@niehs.nih.gov; Waalkes, Michael P.

    2015-02-01

    We studied how protein metallothionein (MT) impacts arsenic-induced oxidative DNA damage (ODD) using cells that poorly express MT (MT-I/II double knockout embryonic cells; called MT-null cells) and wild-type (WT) MT competent cells. Arsenic (as NaAsO{sub 2}) was less cytolethal over 24 h in WT cells (LC{sub 50} = 11.0 ± 1.3 μM; mean ± SEM) than in MT-null cells (LC{sub 50} = 5.6 ± 1.2 μM). ODD was measured by the immuno-spin trapping method. Arsenic (1 or 5 μM; 24 h) induced much less ODD in WT cells (121% and 141% of control, respectively) than in MT-null cells (202% and 260%). In WT cells arsenic caused concentration-dependent increases in MT expression (transcript and protein), and in the metal-responsive transcription factor-1 (MTF-1), which is required to induce the MT gene. In contrast, basal MT levels were not detectable in MT-null cells and unaltered by arsenic exposure. Transfection of MT-I gene into the MT-null cells markedly reduced arsenic-induced ODD levels. The transport genes, Abcc1 and Abcc2 were increased by arsenic in WT cells but either showed no or very limited increases in MT-null cells. Arsenic caused increases in oxidant stress defense genes HO-1 and GSTα2 in both WT and MT-null cells, but to much higher levels in WT cells. WT cells appear more adept at activating metal transport systems and oxidant response genes, although the role of MT in these responses is unclear. Overall, MT protects against arsenic-induced ODD in MT competent cells by potential sequestration of scavenging oxidant radicals and/or arsenic. - Highlights: • Metallothionein blocks arsenic toxicity. • Metallothionein reduces arsenic-induced DNA damage. • Metallothionein may bind arsenic or radicals produced by arsenic.

  14. Low intensity microwave radiation induced oxidative stress, inflammatory response and DNA damage in rat brain.

    Science.gov (United States)

    Megha, Kanu; Deshmukh, Pravin Suryakantrao; Banerjee, Basu Dev; Tripathi, Ashok Kumar; Ahmed, Rafat; Abegaonkar, Mahesh Pandurang

    2015-12-01

    Over the past decade people have been constantly exposed to microwave radiation mainly from wireless communication devices used in day to day life. Therefore, the concerns over potential adverse effects of microwave radiation on human health are increasing. Until now no study has been proposed to investigate the underlying causes of genotoxic effects induced by low intensity microwave exposure. Thus, the present study was undertaken to determine the influence of low intensity microwave radiation on oxidative stress, inflammatory response and DNA damage in rat brain. The study was carried out on 24 male Fischer 344 rats, randomly divided into four groups (n=6 in each group): group I consisted of sham exposed (control) rats, group II-IV consisted of rats exposed to microwave radiation at frequencies 900, 1800 and 2450 MHz, specific absorption rates (SARs) 0.59, 0.58 and 0.66 mW/kg, respectively in gigahertz transverse electromagnetic (GTEM) cell for 60 days (2h/day, 5 days/week). Rats were sacrificed and decapitated to isolate hippocampus at the end of the exposure duration. Low intensity microwave exposure resulted in a frequency dependent significant increase in oxidative stress markers viz. malondialdehyde (MDA), protein carbonyl (PCO) and catalase (CAT) in microwave exposed groups in comparison to sham exposed group (pmicrowave exposed groups (pmicrowave exposed animal (pmicrowave exposed groups as compared to their corresponding values in sham exposed group (pmicrowave radiation induces oxidative stress, inflammatory response and DNA damage in brain by exerting a frequency dependent effect. The study also indicates that increased oxidative stress and inflammatory response might be the factors involved in DNA damage following low intensity microwave exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Increased Chromosomal and Oxidative DNA Damage in Patients with Multinodular Goiter and Their Association with Cancer

    Directory of Open Access Journals (Sweden)

    Hamiyet Donmez-Altuntas

    2017-01-01

    Full Text Available Thyroid nodules are a common clinical problem worldwide. Although thyroid cancer accounts for a small percentage of thyroid nodules, the majority are benign. 8-Hydroxy-2′-deoxyguanosine (8-OHdG levels are a marker of oxidative stress and play a key role in the initiation and development of a range of diseases and cancer types. This study evaluates cytokinesis-block micronucleus cytome (CBMN-cyt assay parameters and plasma 8-OHdG levels and their association with thyroid nodule size and thyroid hormones in patients with multinodular goiter. The study included 32 patients with multinodular goiter and 18 age- and sex-matched healthy controls. CBMN-cyt assay parameters in peripheral blood lymphocytes of patients with multinodular goiter and controls were evaluated, and plasma 8-OHdG levels were measured. The micronucleus (MN frequency (chromosomal DNA damage, apoptotic and necrotic cells (cytotoxicity, and plasma 8-OHdG levels (oxidative DNA damage were significantly higher among patients with multinodular goiter. Our study is the first report of increased chromosomal and oxidative DNA damage in patients with multinodular goiter, which may predict an increased risk of thyroid cancer in these patients. MN frequency and plasma 8-OHdG levels may be markers of the carcinogenic potential of multinodular goiters and could be used for early detection of different cancer types, including thyroid cancer.

  16. Magnetic Hyperthermia and Oxidative Damage to DNA of Human Hepatocarcinoma Cells

    Directory of Open Access Journals (Sweden)

    Filippo Cellai

    2017-04-01

    Full Text Available Nanotechnology is addressing major urgent needs for cancer treatment. We conducted a study to compare the frequency of 3-(2-deoxy-β-d-erythro-pentafuranosylpyrimido[1,2-α]purin-10(3H-one deoxyguanosine (M1dG and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG adducts, biomarkers of oxidative stress and/or lipid peroxidation, on human hepatocarcinoma HepG2 cells exposed to increasing levels of Fe3O4-nanoparticles (NPs versus untreated cells at different lengths of incubations, and in the presence of increasing exposures to an alternating magnetic field (AMF of 186 kHz using 32P-postlabeling. The levels of oxidative damage tended to increase significantly after ≥24 h of incubations compared to controls. The oxidative DNA damage tended to reach a steady-state after treatment with 60 μg/mL of Fe3O4-NPs. Significant dose–response relationships were observed. A greater adduct production was observed after magnetic hyperthermia, with the highest amounts of oxidative lesions after 40 min exposure to AMF. The effects of magnetic hyperthermia were significantly increased with exposure and incubation times. Most important, the levels of oxidative lesions in AMF exposed NP treated cells were up to 20-fold greater relative to those observed in nonexposed NP treated cells. Generation of oxidative lesions may be a mechanism by which magnetic hyperthermia induces cancer cell death.

  17. MTH1 deficiency selectively increases non-cytotoxic oxidative DNA damage in lung cancer cells: more bad news than good?

    Science.gov (United States)

    Abbas, Hussein H K; Alhamoudi, Kheloud M H; Evans, Mark D; Jones, George D D; Foster, Steven S

    2018-04-16

    Targeted therapies are based on exploiting cancer-cell-specific genetic features or phenotypic traits to selectively kill cancer cells while leaving normal cells unaffected. Oxidative stress is a cancer hallmark phenotype. Given that free nucleotide pools are particularly vulnerable to oxidation, the nucleotide pool sanitising enzyme, MTH1, is potentially conditionally essential in cancer cells. However, findings from previous MTH1 studies have been contradictory, meaning the relevance of MTH1 in cancer is still to be determined. Here we ascertained the role of MTH1 specifically in lung cancer cell maintenance, and the potential of MTH1 inhibition as a targeted therapy strategy to improve lung cancer treatments. Using siRNA-mediated knockdown or small-molecule inhibition, we tested the genotoxic and cytotoxic effects of MTH1 deficiency on H23 (p53-mutated), H522 (p53-mutated) and A549 (wildtype p53) non-small cell lung cancer cell lines relative to normal MRC-5 lung fibroblasts. We also assessed if MTH1 inhibition augments current therapies. MTH1 knockdown increased levels of oxidatively damaged DNA and DNA damage signaling alterations in all lung cancer cell lines but not normal fibroblasts, despite no detectable differences in reactive oxygen species levels between any cell lines. Furthermore, MTH1 knockdown reduced H23 cell proliferation. However, unexpectedly, it did not induce apoptosis in any cell line or enhance the effects of gemcitabine, cisplatin or radiation in combination treatments. Contrastingly, TH287 and TH588 MTH1 inhibitors induced apoptosis in H23 and H522 cells, but only increased oxidative DNA damage levels in H23, indicating that they kill cells independently of DNA oxidation and seemingly via MTH1-distinct mechanisms. MTH1 has a NSCLC-specific p53-independent role for suppressing DNA oxidation and genomic instability, though surprisingly the basis of this may not be reactive-oxygen-species-associated oxidative stress. Despite this, overall

  18. Phototherapy causes DNA damage in peripheral mononuclear leukocytes in term infants.

    Science.gov (United States)

    Aycicek, Ali; Kocyigit, Abdurrahim; Erel, Ozcan; Senturk, Hakan

    2008-01-01

    Our aim was to determine whether endogenous mononuclear leukocyte DNA strand is a target of phototherapy. The study included 65 term infants aged between 3-10 days that had been exposed to intensive (n = 23) or conventional (n = 23) phototherapy for at least 48 hours due to neonatal jaundice, and a control group (n = 19). DNA damage was assayed by single-cell alkaline gel electrophoresis (comet assay). Plasma total antioxidant capacity and total oxidant status levels were also measured, and correlation between DNA damage and oxidative stress was investigated. Mean values of DNA damage scores in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p Total oxidant status levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.005). Mean (standard deviation) values were 18.1 (4.2), 16.9 (4.4), 13.5 (4.2) micromol H2O2 equivalent/L, respectively. Similarly, oxidative stress index levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.041). Plasma total antioxidant capacity and total bilirubin levels did not differ between the groups (p > 0.05). There were no significant correlations between DNA damage scores and bilirubin, total oxidant status and oxidative stress levels in either phototherapy group (p > 0.05). Both conventional phototherapy and intensive phototherapy cause endogenous mononuclear leukocyte DNA damage in jaundiced term infants.

  19. Heavy Metal-Induced Oxidative DNA Damage in Earthworms: A Review

    Directory of Open Access Journals (Sweden)

    Takeshi Hirano

    2010-01-01

    Full Text Available Earthworms can be used as a bio-indicator of metal contamination in soil, Earlier reports claimed the bioaccumulation of heavy metals in earthworm tissues, while the metal-induced mutagenicity reared in contaminated soils for long duration. But we examined the metal-induced mutagenicity in earthworms reared in metal containing culture beddings. In this experiment we observed the generation of 8-oxoguanine (8-oxo-Gua in earthworms exposed to cadmium and nickel in soil. 8-oxo-Gua is a major premutagenic form of oxidative DNA damage that induces GC-to-TA point mutations, leading to carcinogenesis.

  20. DNA damage and repair in age-related macular degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Szaflik, Jacek P. [Department of Ophthalmology, Medical University of Warsaw and Samodzielny Publiczny Szpital Okulistyczny, Sierakowskiego 13, 03-710 Warsaw (Poland); Janik-Papis, Katarzyna; Synowiec, Ewelina; Ksiazek, Dominika [Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland); Zaras, Magdalena [Department of Ophthalmology, Medical University of Warsaw and Samodzielny Publiczny Szpital Okulistyczny, Sierakowskiego 13, 03-710 Warsaw (Poland); Wozniak, Katarzyna [Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland); Szaflik, Jerzy [Department of Ophthalmology, Medical University of Warsaw and Samodzielny Publiczny Szpital Okulistyczny, Sierakowskiego 13, 03-710 Warsaw (Poland); Blasiak, Janusz, E-mail: januszb@biol.uni.lodz.pl [Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland)

    2009-10-02

    Age-related macular degeneration (AMD) is a retinal degenerative disease that is the main cause of vision loss in individuals over the age of 55 in the Western world. Clinically relevant AMD results from damage to the retinal pigment epithelial (RPE) cells thought to be mainly caused by oxidative stress. The stress also affects the DNA of RPE cells, which promotes genome instability in these cells. These effects may coincide with the decrease in the efficacy of DNA repair with age. Therefore individuals with DNA repair impaired more than average for a given age may be more susceptible to AMD if oxidative stress affects their RPE cells. This may be helpful in AMD risk assessment. In the present work we determined the level of basal (measured in the alkaline comet assay) endogenous and endogenous oxidative DNA damage, the susceptibility to exogenous mutagens and the efficacy of DNA repair in lymphocytes of 100 AMD patients and 110 age-matched individuals without visual disturbances. The cells taken from AMD patients displayed a higher extent of basal endogenous DNA damage without differences between patients of dry and wet forms of the disease. DNA double-strand breaks did not contribute to the observed DNA damage as checked by the neutral comet assay and pulsed field gel electrophoresis. The extent of oxidative modification to DNA bases was grater in AMD patients than in the controls, as probed by DNA repair enzymes NTH1 and Fpg. Lymphocytes from AMD patients displayed a higher sensitivity to hydrogen peroxide and UV radiation and repaired lesions induced by these factors less effectively than the cells from the control individuals. We postulate that the impaired efficacy of DNA repair may combine with enhanced sensitivity of RPE cells to blue and UV lights, contributing to the pathogenesis of AMD.

  1. DNA damage and repair in age-related macular degeneration

    International Nuclear Information System (INIS)

    Szaflik, Jacek P.; Janik-Papis, Katarzyna; Synowiec, Ewelina; Ksiazek, Dominika; Zaras, Magdalena; Wozniak, Katarzyna; Szaflik, Jerzy; Blasiak, Janusz

    2009-01-01

    Age-related macular degeneration (AMD) is a retinal degenerative disease that is the main cause of vision loss in individuals over the age of 55 in the Western world. Clinically relevant AMD results from damage to the retinal pigment epithelial (RPE) cells thought to be mainly caused by oxidative stress. The stress also affects the DNA of RPE cells, which promotes genome instability in these cells. These effects may coincide with the decrease in the efficacy of DNA repair with age. Therefore individuals with DNA repair impaired more than average for a given age may be more susceptible to AMD if oxidative stress affects their RPE cells. This may be helpful in AMD risk assessment. In the present work we determined the level of basal (measured in the alkaline comet assay) endogenous and endogenous oxidative DNA damage, the susceptibility to exogenous mutagens and the efficacy of DNA repair in lymphocytes of 100 AMD patients and 110 age-matched individuals without visual disturbances. The cells taken from AMD patients displayed a higher extent of basal endogenous DNA damage without differences between patients of dry and wet forms of the disease. DNA double-strand breaks did not contribute to the observed DNA damage as checked by the neutral comet assay and pulsed field gel electrophoresis. The extent of oxidative modification to DNA bases was grater in AMD patients than in the controls, as probed by DNA repair enzymes NTH1 and Fpg. Lymphocytes from AMD patients displayed a higher sensitivity to hydrogen peroxide and UV radiation and repaired lesions induced by these factors less effectively than the cells from the control individuals. We postulate that the impaired efficacy of DNA repair may combine with enhanced sensitivity of RPE cells to blue and UV lights, contributing to the pathogenesis of AMD.

  2. APE2 Zf-GRF facilitates 3'-5' resection of DNA damage following oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, Bret D.; Berman, Zachary; Mueller, Geoffrey A.; Lin, Yunfeng; Chang, Timothy; Andres, Sara N.; Wojtaszek, Jessica L.; DeRose, Eugene F.; Appel, C. Denise; London, Robert E.; Yan, Shan; Williams, R. Scott

    2016-12-27

    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.

  3. Photoelectrochemical Sensors for the Rapid Detection of DNA Damage Induced by Some Nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Jamaluddin Ahmed

    2010-06-01

    Full Text Available Photoelectrochemcal sensors were developed for the rapid detection of oxidative DNA damage induced by titanium dioxide and polystyrene nanoparticles. Each sensor is a multilayer film prepared on a tin oxide nanoparticle electrode using layer- by-layer self assembly and is composed of separate layer of a photoelectrochemical indicator, DNA. The organic compound and heavy metals represent genotoxic chemicals leading two major damaging mechanisms, DNA adduct formation and DNA oxidation. The DNA damage is detected by monitoring the change of photocurrent of the indicator. In one sensor configuration, a DNA intercalator, Ru(bpy2 (dppz2+ [bpy=2, 2′ -bipyridine, dppz=dipyrido( 3, 2-a: 2′ 3′-c phenazine], was employed as the photoelectrochemical indicator. The damaged DNA on the sensor bound lesser Ru(bpy2 (dppz2+ than the intact DNA, resulting in a drop in photocurrent. In another configuration, ruthenium tris(bipyridine was used as the indicator and was immobilized on the electrode underneath the DNA layer. After oxidative damage, the DNA bases became more accessible to photoelectrochemical oxidation than the intact DNA, producing a rise in photocurrent. Both sensors displayed substantial photocurrent change after incubation in titanium dioxide / polystyrene solution in a time – dependent manner. According to the data, damage of the DNA film was completed in 1h in titanium dioxide / polystyrene solution. In addition, the titanium dioxide induced much more sever damage than polysterene. The results were verified independently by gel electrophoresis and UV-Vis absorbance experiments. The photoelectrochemical reaction can be employed as a new and inexpensive screening tool for the rapid assessment of the genotoxicity of existing and new chemicals.

  4. Photoelectrochemical sensors for the rapid detection of DNA damage Induced by some nanoparticles

    International Nuclear Information System (INIS)

    Ahmed, M.J.; Zhang, B.T.; Guo, L.H.

    2010-01-01

    Photoelectrochemical sensors were developed for the rapid detection of oxidative DNA damage induced by titanium dioxide and polystyrene nanoparticles. Each sensor is a multilayer film prepared on a tin oxide nanoparticle electrode using layer- by-layer self assembly and is composed of separate layer of a photoelectrochemical indicator, DNA. The organic compound and heavy metals represent genotoxic chemicals leading two major damaging mechanisms, DNA adduct formation and DNA oxidation. The DNA damage is detected by monitoring the change of photocurrent of the indicator. In one sensor configuration, a DNA intercalator, Ru(bpy)2 (dppz)2+ [bpy=2, 2' -bipyridine, dppz=dipyrido (3, 2-a: 2' 3'-c) phenazine], was employed as the photoelectrochemical indicator. The damaged DNA on the sensor bound lesser Ru(bpy)2 (dppz)2+ than the intact DNA, resulting in a drop in photocurrent. In another configuration, ruthenium tris(bipyridine) was used as the indicator and was immobilized on the electrode underneath the DNA layer. After oxidative damage, the DNA bases became more accessible to photoelectrochemical oxidation than the intact DNA, producing a rise in photocurrent. Both sensors displayed substantial photocurrent change after incubation in titanium dioxide / polystyrene solution in a time . dependent manner. According to the data, damage of the DNA film was completed in 1h in titanium dioxide / polystyrene solution. In addition, the titanium dioxide induced much more sever damage than polystyrene. The results were verified independently by gel electrophoresis and UV-Vis absorbance experiments. The photoelectrochemical reaction can be employed as a new and inexpensive screening tool for the rapid assessment of the genotoxicity of existing and new chemicals. (author)

  5. GC-Rich Extracellular DNA Induces Oxidative Stress, Double-Strand DNA Breaks, and DNA Damage Response in Human Adipose-Derived Mesenchymal Stem Cells.

    Science.gov (United States)

    Kostyuk, Svetlana; Smirnova, Tatiana; Kameneva, Larisa; Porokhovnik, Lev; Speranskij, Anatolij; Ershova, Elizaveta; Stukalov, Sergey; Izevskaya, Vera; Veiko, Natalia

    2015-01-01

    Cell free DNA (cfDNA) circulates throughout the bloodstream of both healthy people and patients with various diseases. CfDNA is substantially enriched in its GC-content as compared with human genomic DNA. Exposure of haMSCs to GC-DNA induces short-term oxidative stress (determined with H2DCFH-DA) and results in both single- and double-strand DNA breaks (comet assay and γH2AX, foci). As a result in the cells significantly increases the expression of repair genes (BRCA1 (RT-PCR), PCNA (FACS)) and antiapoptotic genes (BCL2 (RT-PCR and FACS), BCL2A1, BCL2L1, BIRC3, and BIRC2 (RT-PCR)). Under the action of GC-DNA the potential of mitochondria was increased. Here we show that GC-rich extracellular DNA stimulates adipocyte differentiation of human adipose-derived mesenchymal stem cells (haMSCs). Exposure to GC-DNA leads to an increase in the level of RNAPPARG2 and LPL (RT-PCR), in the level of fatty acid binding protein FABP4 (FACS analysis) and in the level of fat (Oil Red O). GC-rich fragments in the pool of cfDNA can potentially induce oxidative stress and DNA damage response and affect the direction of mesenchymal stem cells differentiation in human adipose-derived mesenchymal stem cells. Such a response may be one of the causes of obesity or osteoporosis.

  6. Is the Oxidative DNA Damage Level of Human Lymphocyte Correlated with the Antioxidant Capacity of Serum or the Base Excision Repair Activity of Lymphocyte?

    Directory of Open Access Journals (Sweden)

    Yi-Chih Tsai

    2013-01-01

    Full Text Available A random screening of human blood samples from 24 individuals of nonsmoker was conducted to examine the correlation between the oxidative DNA damage level of lymphocytes and the antioxidant capacity of serum or the base excision repair (BER activity of lymphocytes. The oxidative DNA damage level was measured with comet assay containing Fpg/Endo III cleavage, and the BER activity was estimated with a modified comet assay including nuclear extract of lymphocytes for enzymatic cleavage. Antioxidant capacity was determined with trolox equivalent antioxidant capacity assay. We found that though the endogenous DNA oxidation levels varied among the individuals, each individual level appeared to be steady for at least 1 month. Our results indicate that the oxidative DNA damage level is insignificantly or weakly correlated with antioxidant capacity or BER activity, respectively. However, lymphocytes from carriers of Helicobacter pylori (HP or Hepatitis B virus (HBV tend to give higher levels of oxidative DNA damage (P<0.05. Though sera of this group of individuals show no particular tendency with reduced antioxidant capacity, the respective BER activities of lymphocytes are lower in average (P<0.05. Thus, reduction of repair activity may be associated with the genotoxic effect of HP or HBV infection.

  7. Assessment of DNA damage and oxidative stress induced by radiation in Eisenia fetida

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2012-04-15

    Exposure of eukaryotic cells to ionizing radiation results in the immediate formation of free radicals and the occurrence of oxidative cell damage. Recently International Commission on Radiological Protection (ICRP) requires the effect data of ionizing radiation on non-human biota for the radiological protection of the environment. Based on their radioecological properties and their important role in the soil ecosystem, earthworms have been identified by the ICRP as one of the reference animals and plants (RAPs) to be used in environmental radiation protection. The investigation shows that oxidative stress is closely related to the exposed dose of radiation in the environment. To evaluate oxidative stress by ionizing radiation in the earthworm, we performed several experiments. The comet assay is known as a measurement which is one of the best techniques in assessing the DNA damage by oxidative stress. The SOD is a key enzyme in protecting cells against oxidative stress. An increase in the level of antioxidant enzyme such as SOD indicated that the exposure to radiation caused stress responses. Glutathione oxidation is considered as a maker for detection of reactive oxygen species (ROS). The GSSG levels increased progressively with increased exposure dose of ionizing radiation, which suggested a dose-dependent ROS generation.

  8. Oxidative DNA as related to cancer and aging

    International Nuclear Information System (INIS)

    Ames, B.N.

    1987-01-01

    DNA damage in man can result from a variety of endogenous processes. Of particular importance as endogenous processes may be metabolic pathways that generate oxygen radicals and other reactive oxygen species. Oxygen radicals have been shown to produce DNA base damage and strand breaks. Two products that are formed in DNA in vitro by chemical oxidation or ionizing radiation (and oxidative mutagen) are thymine glycol and hydroxymethyl-uracil, both oxidation products of thymine. Specific mammalian DNA repair systems are known to excise these lesions from DNA in vitro. The authors' laboratory has recently reported the identification, in both human and rat urine, of thymine glycol, thymidine glycol, and hydroxymethyluracil. They now have considerable evidence that these products are derived from the repair of oxidized DNA. The total output of these three compounds represents the formation of about 1,000 oxidized thymine residues per cell per day in man. Since these products are only three of a considerable number of types of oxidative DNA damage products described by radiobiologists, there are likely to be several thousand oxidative DNA hits per cell per day in man. Rats, which have a higher specific metabolic rate and a shorter life span, excrete about 15 times more thymine glycol, thymidine glycol, and hydroxymethyluracil per kilogram body weight. The authors also describe new methods for measuring the levels, which are considerable, of hydrogen peroxide and lipid hydroperoxides in normal plasma and tissues. These non-invasive assays of DNA and other oxidation products may allow the direct testing of current theories that relate oxidative metabolism to the processes of cancer and aging in man

  9. Cytogenetic status and oxidative DNA-damage induced by atorvastatin in human peripheral blood lymphocytes: Standard and Fpg-modified comet assay

    International Nuclear Information System (INIS)

    Gajski, Goran; Garaj-Vrhovac, Vera; Orescanin, Visnja

    2008-01-01

    To investigate the genotoxic potential of atorvastatin on human lymphocytes in vitro standard comet assay was used in the evaluation of basal DNA damage and to investigate possible oxidative DNA damage produced by reactive oxygen species (ROS) Fpg-modified version of comet assay was also conducted. In addition to these techniques the new criteria for scoring micronucleus test were applied for more complete detection of baseline damage in binuclear lymphocytes exposed to atorvastatin 80 mg/day in different time periods by virtue of measuring the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. All parameters obtained with the standard comet assay and Fpg-modified comet assay were significantly higher in the treated than in control lymphocytes. The Fpg-modified comet assay showed a significantly greater tail length, tail intensity, and tail moment in all treated lymphocytes than did the standard comet assay, which suggests that oxidative stress is likely to be responsible for DNA damage. DNA damage detected by the standard comet assay indicates that some other mechanism is also involved. In addition to the comet assay, a total number of micronuclei, nucleoplasmic bridges and nuclear buds were significantly higher in the exposed than in controlled lymphocytes. Regression analyses showed a positive correlation between the results obtained by the comet (Fpg-modified and standard) and micronucleus assay. Overall, the study demonstrated that atorvastatin in its highest dose is capable of producing damage on the level of DNA molecule and cell

  10. Cytogenetic status and oxidative DNA-damage induced by atorvastatin in human peripheral blood lymphocytes: Standard and Fpg-modified comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Gajski, Goran [Institute for Medical Research and Occupational Health, Mutagenesis Unit, 10000 Zagreb (Croatia); Garaj-Vrhovac, Vera [Institute for Medical Research and Occupational Health, Mutagenesis Unit, 10000 Zagreb (Croatia); Orescanin, Visnja [Ruder Boskovic Institute, 10000 Zagreb (Croatia)

    2008-08-15

    To investigate the genotoxic potential of atorvastatin on human lymphocytes in vitro standard comet assay was used in the evaluation of basal DNA damage and to investigate possible oxidative DNA damage produced by reactive oxygen species (ROS) Fpg-modified version of comet assay was also conducted. In addition to these techniques the new criteria for scoring micronucleus test were applied for more complete detection of baseline damage in binuclear lymphocytes exposed to atorvastatin 80 mg/day in different time periods by virtue of measuring the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. All parameters obtained with the standard comet assay and Fpg-modified comet assay were significantly higher in the treated than in control lymphocytes. The Fpg-modified comet assay showed a significantly greater tail length, tail intensity, and tail moment in all treated lymphocytes than did the standard comet assay, which suggests that oxidative stress is likely to be responsible for DNA damage. DNA damage detected by the standard comet assay indicates that some other mechanism is also involved. In addition to the comet assay, a total number of micronuclei, nucleoplasmic bridges and nuclear buds were significantly higher in the exposed than in controlled lymphocytes. Regression analyses showed a positive correlation between the results obtained by the comet (Fpg-modified and standard) and micronucleus assay. Overall, the study demonstrated that atorvastatin in its highest dose is capable of producing damage on the level of DNA molecule and cell.

  11. GC-Rich Extracellular DNA Induces Oxidative Stress, Double-Strand DNA Breaks, and DNA Damage Response in Human Adipose-Derived Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Svetlana Kostyuk

    2015-01-01

    Full Text Available Background. Cell free DNA (cfDNA circulates throughout the bloodstream of both healthy people and patients with various diseases. CfDNA is substantially enriched in its GC-content as compared with human genomic DNA. Principal Findings. Exposure of haMSCs to GC-DNA induces short-term oxidative stress (determined with H2DCFH-DA and results in both single- and double-strand DNA breaks (comet assay and γH2AX, foci. As a result in the cells significantly increases the expression of repair genes (BRCA1 (RT-PCR, PCNA (FACS and antiapoptotic genes (BCL2 (RT-PCR and FACS, BCL2A1, BCL2L1, BIRC3, and BIRC2 (RT-PCR. Under the action of GC-DNA the potential of mitochondria was increased. Here we show that GC-rich extracellular DNA stimulates adipocyte differentiation of human adipose-derived mesenchymal stem cells (haMSCs. Exposure to GC-DNA leads to an increase in the level of RNAPPARG2 and LPL (RT-PCR, in the level of fatty acid binding protein FABP4 (FACS analysis and in the level of fat (Oil Red O. Conclusions. GC-rich fragments in the pool of cfDNA can potentially induce oxidative stress and DNA damage response and affect the direction of mesenchymal stem cells differentiation in human adipose—derived mesenchymal stem cells. Such a response may be one of the causes of obesity or osteoporosis.

  12. Personal exposure to ultrafine particles and oxidative DNA damage

    DEFF Research Database (Denmark)

    Vinzents, Peter S; Møller, Peter; Sørensen, Mette

    2005-01-01

    Exposure to ultrafine particles (UFPs) from vehicle exhaust has been related to risk of cardiovascular and pulmonary disease and cancer, even though exposure assessment is difficult. We studied personal exposure in terms of number concentrations of UFPs in the breathing zone, using portable instr......, particularly during bicycling in traffic. The results indicate that biologic effects of UFPs occur at modest exposure, such as that occurring in traffic, which supports the relationship of UFPs and the adverse health effects of air pollution.......Exposure to ultrafine particles (UFPs) from vehicle exhaust has been related to risk of cardiovascular and pulmonary disease and cancer, even though exposure assessment is difficult. We studied personal exposure in terms of number concentrations of UFPs in the breathing zone, using portable...... instruments in six 18-hr periods in 15 healthy nonsmoking subjects. Exposure contrasts of outdoor pollution were achieved by bicycling in traffic for 5 days and in the laboratory for 1 day. Oxidative DNA damage was assessed as strand breaks and oxidized purines in mononuclear cells isolated from venous blood...

  13. Single Nucleotide Polymorphisms in Noncoding Regions of Rad51C Do Not Change the Risk of Unselected Breast Cancer but They Modulate the Level of Oxidative Stress and the DNA Damage Characteristics

    DEFF Research Database (Denmark)

    Gresner, Peter; Gromadzinska, Jolanta; Jablonska, Ewa

    2014-01-01

    affect the unselected BrC risk. Contrary to this, carriers of rs12946522, rs16943176, rs12946397 and rs17222691 rare-alleles were found to present significantly increased level of blood plasma TBARS compared to respective wild-type homozygotes (p... decreased fraction of oxidatively generated DNA damage (34% of total damaged DNA) in favor of DNA strand breakage, with no effect on total DNA damage, unlike respective wild-types, among which more evenly distributed proportions between oxidatively damaged DNA (48% of total DNA damage) and DNA strand...

  14. Hydroxyl radical formation and oxidative DNA damage induced by areca quid in vivo.

    Science.gov (United States)

    Chen, Chiu-Lan; Chi, Chin-Wen; Liu, Tsung-Yun

    2002-02-01

    Chewing areca quid (AQ) has been implicated as a major risk factor for the development of oral squamous-cell carcinoma (OSCC). Recent studies have suggested that AQ-generated reactive oxygen species (ROS) is one of the contributing factors for oral carcinogenesis. However, the AQ used in Taiwan is different from that used in other countries. This study is designed to test whether ROS are generated and the consequent effects in locally prepared AQ in vivo. We measured the hydroxyl radical formation, as represented by the presence of o- and m-tyrosine in saliva from volunteers who chewed AQ containing 20 mg phenylalanine. Their saliva contained significantly higher amounts (p betel leaf. We further tested the oxidative DNA damaging effect of the reconstituted AQ, as evidenced by the elevation of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels, in hamster buccal pouch. Following daily painting for 14 d, the 8-OH-dG level in hamster buccal pouch is significantly elevated (p < .05) in the AQ-treated group versus the controls. These findings demonstrate that ROS, such as hydroxyl radical, are formed in the human oral cavity during AQ chewing, and chewing such prepared AQ might cause oxidative DNA damage to the surrounding tissues.

  15. Oxidative DNA damage during night shift work.

    Science.gov (United States)

    Bhatti, Parveen; Mirick, Dana K; Randolph, Timothy W; Gong, Jicheng; Buchanan, Diana Taibi; Zhang, Junfeng Jim; Davis, Scott

    2017-09-01

    We previously reported that compared with night sleep, day sleep among shift workers was associated with reduced urinary excretion of 8-hydroxydeoxyguanosine (8-OH-dG), potentially reflecting a reduced ability to repair 8-OH-dG lesions in DNA. We identified the absence of melatonin during day sleep as the likely causative factor. We now investigate whether night work is also associated with reduced urinary excretion of 8-OH-dG. For this cross-sectional study, 50 shift workers with the largest negative differences in night work versus night sleep circulating melatonin levels (measured as 6-sulfatoxymelatonin in urine) were selected from among the 223 shift workers included in our previous study. 8-OH-dG concentrations were measured in stored urine samples using high performance liquid chromatography with electrochemical detection. Mixed effects models were used to compare night work versus night sleep 8-OH-dG levels. Circulating melatonin levels during night work (mean=17.1 ng/mg creatinine/mg creatinine) were much lower than during night sleep (mean=51.7 ng/mg creatinine). In adjusted analyses, average urinary 8-OH-dG levels during the night work period were only 20% of those observed during the night sleep period (95% CI 10% to 30%; psleep, is associated with reduced repair of 8-OH-dG lesions in DNA and that the effect is likely driven by melatonin suppression occurring during night work relative to night sleep. If confirmed, future studies should evaluate melatonin supplementation as a means to restore oxidative DNA damage repair capacity among shift workers. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  16. Global DNA methylation and oxidative stress biomarkers in workers exposed to metal oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Saou-Hsing; Wu, Wei-Te; Liao, Hui-Yi [National Institute of Environmental Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan (China); Chen, Chao-Yu; Tsai, Cheng-Yen; Jung, Wei-Ting [Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan (China); Lee, Hui-Ling, E-mail: huilinglee3573@gmail.com [Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan (China)

    2017-06-05

    Highlights: • Global methylation and oxidative DNA damage levels in nanomaterial handling workers were assessed. • 8-isoprostane in exhaled breath condensate of workers exposed to nanoparticles was higher. • 8-OHdG was negatively correlated with global methylation. • Exposure to metal oxide nanoparticles may lead to global methylation and DNA oxidative damage. - Abstract: This is the first study to assess global methylation, oxidative DNA damage, and lipid peroxidation in workers with occupational exposure to metal oxide nanomaterials (NMs). Urinary and white blood cell (WBC) 8-hydroxydeoxyguanosine (8-OHdG), and exhaled breath condensate (EBC) 8-isoprostane were measured as oxidative stress biomarkers. WBC global methylation was measured as an epigenetic alteration. Exposure to TiO{sub 2}, SiO{sub 2,} and indium tin oxide (ITO) resulted in significantly higher oxidative biomarkers such as urinary 8-OHdG and EBC 8-isoprostane. However, significantly higher WBC 8-OHdG and lower global methylation were only observed in ITO handling workers. Significant positive correlations were noted between WBC and urinary 8-OHdG (Spearman correlation r = 0.256, p = 0.003). Furthermore, a significant negative correlation was found between WBC 8-OHdG and global methylation (r = −0.272, p = 0.002). These results suggest that exposure to metal oxide NMs may lead to global methylation, DNA oxidative damage, and lipid peroxidation.

  17. Repair activity of oxidatively damaged DNA and telomere length in human lung epithelial cells after exposure to multi-walled carbon nanotubes

    DEFF Research Database (Denmark)

    Borghini, Andrea; Roursgaard, Martin; Andreassi, Maria Grazia

    2017-01-01

    One type of carbon nanotubes (CNTs) (MWCNT-7, from Mitsui) has been classified as probably carcinogenic to humans, however insufficient data does not warrant the same classification for other types of CNTs. Experimental data indicate that CNT exposure can result in oxidative stress and DNA damage...... the cells toward replicative senescence, assessed by attrition of telomeres. To investigate this, H2O2 and KBrO3 were used to induce DNA damage in the cells and the effect of pre-exposure to MWCNT tested for a change in repair activity inside the cells or in the extract of treated cells. The effect of MWCNT...... in cultured cells, whereas these materials appear to induce low or no mutagenicity. Therefore, the present study aimed to investigate whether in vitro exposure of cultured airway epithelial cells (A549) to multi-walled CNTs (MWCNTs) could increase the DNA repair activity of oxidatively damaged DNA and drive...

  18. Targeting Oxidatively Induced DNA Damage Response in Cancer: Opportunities for Novel Cancer Therapies

    Directory of Open Access Journals (Sweden)

    Pierpaola Davalli

    2018-01-01

    Full Text Available Cancer is a death cause in economically developed countries that results growing also in developing countries. Improved outcome through targeted interventions faces the scarce selectivity of the therapies and the development of resistance to them that compromise the therapeutic effects. Genomic instability is a typical cancer hallmark due to DNA damage by genetic mutations, reactive oxygen and nitrogen species, ionizing radiation, and chemotherapeutic agents. DNA lesions can induce and/or support various diseases, including cancer. The DNA damage response (DDR is a crucial signaling-transduction network that promotes cell cycle arrest or cell death to repair DNA lesions. DDR dysregulation favors tumor growth as downregulated or defective DDR generates genomic instability, while upregulated DDR may confer treatment resistance. Redox homeostasis deeply and capillary affects DDR as ROS activate/inhibit proteins and enzymes integral to DDR both in healthy and cancer cells, although by different routes. DDR regulation through modulating ROS homeostasis is under investigation as anticancer opportunity, also in combination with other treatments since ROS affect DDR differently in the patients during cancer development and treatment. Here, we highlight ROS-sensitive proteins whose regulation in oxidatively induced DDR might allow for selective strategies against cancer that are better tailored to the patients.

  19. Characterization of protein interactomes of DNA damages: application to oxidation injuries

    International Nuclear Information System (INIS)

    Pietras-Barbier, Ewa

    2013-01-01

    Cyclo-nucleosides are complex DNA damages implying both bases and sugar residues. They are generated by free radicals, in particular by the effect of ionizing radiations, and are not easily covered by cellular mechanisms. Using a protein trapping technique on probes containing these injuries, the negative influence of cyclo-nucleosides on the recognition of its target sequence by a DREF transcription factor and on the interactions of PARP1 with DNA have been identified. Interactions between Fpg bacterial glycosylase and cyclo-nucleosides have been analysed and it has been found that this enzyme has an affinity for them, without excision activity. Finally, a Thermococcus gammatolerans radiation resistant archae has been studied: the formation of simple and complex oxidation injuries at strong radiation doses has been measured and the action mechanism of two new glycosylases has been explained. (author) [fr

  20. Repair of Clustered Damage and DNA Polymerase Iota.

    Science.gov (United States)

    Belousova, E A; Lavrik, O I

    2015-08-01

    Multiple DNA lesions occurring within one or two turns of the DNA helix known as clustered damage are a source of double-stranded DNA breaks, which represent a serious threat to the cells. Repair of clustered lesions is accomplished in several steps. If a clustered lesion contains oxidized bases, an individual DNA lesion is repaired by the base excision repair (BER) mechanism involving a specialized DNA polymerase after excising DNA damage. Here, we investigated DNA synthesis catalyzed by DNA polymerase iota using damaged DNA templates. Two types of DNA substrates were used as model DNAs: partial DNA duplexes containing breaks of different length, and DNA duplexes containing 5-formyluracil (5-foU) and uracil as a precursor of apurinic/apyrimidinic sites (AP) in opposite DNA strands. For the first time, we showed that DNA polymerase iota is able to catalyze DNA synthesis using partial DNA duplexes having breaks of different length as substrates. In addition, we found that DNA polymerase iota could catalyze DNA synthesis during repair of clustered damage via the BER system by using both undamaged and 5-foU-containing templates. We found that hPCNA (human proliferating cell nuclear antigen) increased efficacy of DNA synthesis catalyzed by DNA polymerase iota.

  1. Radiation damage to DNA-binding proteins

    International Nuclear Information System (INIS)

    Culard, G.; Eon, S.; DeVuyst, G.; Charlier, M.; Spotheim-Maurizot, M.

    2003-01-01

    The DNA-binding properties of proteins are strongly affected upon irradiation. The tetrameric lactose repressor (a dimer of dimers) losses its ability to bind operator DNA as soon as at least two damages per protomer of each dimer occur. The monomeric MC1 protein losses its ability to bind DNA in two steps : i) at low doses only the specific binding is abolished, whereas the non-specific one is still possible; ii) at high doses all binding vanishes. Moreover, the DNA bending induced by MC1 binding is less pronounced for a protein that underwent the low dose irradiation. When the entire DNA-protein complexes are irradiated, the observed disruption of the complexes is mainly due to the damage of the proteins and not to that of DNA. The doses necessary for complex disruption are higher than those inactivating the free protein. This difference, larger for MC1 than for lactose repressor, is due to the protection of the protein by the bound DNA. The oxidation of the protein side chains that are accessible to the radiation-induced hydroxyl radicals seems to represent the inactivating damage

  2. Mitochondrial and Nuclear DNA Damage and Repair in Age-Related Macular Degeneration

    Directory of Open Access Journals (Sweden)

    Janusz Blasiak

    2013-01-01

    Full Text Available Aging and oxidative stress seem to be the most important factors in the pathogenesis of age-related macular degeneration (AMD, a condition affecting many elderly people in the developed world. However, aging is associated with the accumulation of oxidative damage in many biomolecules, including DNA. Furthermore, mitochondria may be especially important in this process because the reactive oxygen species produced in their electron transport chain can damage cellular components. Therefore, the cellular response to DNA damage, expressed mainly through DNA repair, may play an important role in AMD etiology. In several studies the increase in mitochondrial DNA (mtDNA damage and mutations, and the decrease in the efficacy of DNA repair have been correlated with the occurrence and the stage of AMD. It has also been shown that mitochondrial DNA accumulates more DNA lesions than nuclear DNA in AMD. However, the DNA damage response in mitochondria is executed by nucleus-encoded proteins, and thus mutagenesis in nuclear DNA (nDNA may affect the ability to respond to mutagenesis in its mitochondrial counterpart. We reported that lymphocytes from AMD patients displayed a higher amount of total endogenous basal and oxidative DNA damage, exhibited a higher sensitivity to hydrogen peroxide and UV radiation, and repaired the lesions induced by these factors less effectively than did cells from control individuals. We postulate that poor efficacy of DNA repair (i.e., is impaired above average for a particular age when combined with the enhanced sensitivity of retinal pigment epithelium cells to environmental stress factors, contributes to the pathogenesis of AMD. Collectively, these data suggest that the cellular response to both mitochondrial and nuclear DNA damage may play an important role in AMD pathogenesis.

  3. Radiation and non-radiation damage to DNA. Onset of molecular instability and carcinogenesis. Theoretical explorations on DNA damage and repair

    International Nuclear Information System (INIS)

    Pinak, Miroslay; Bunta, J.K.

    2006-01-01

    The current work is focused on results of molecular dynamics simulations performed on two DNA damages: 8-oxoguanine as the most significant oxidative damage leading to transversion mutation cytosine-guanine→adenine-thymine', which is common mutation found in human cancer cells; and on the DNA strand break, the type of damage that is considered to be one of the most significant damage leading to genetic instability that may result in enhanced cell proliferation or carcinogenesis. Except the structural changes induced by these two lesions the role and importance of electrostatic energy in recognition process in which a respective repair enzyme recognizes damaged DNA site is also described. Among the significant results can be included the fact, that most of the damages on DNA alternate locally electronic state by modifying chemical and electron orbital configuration. This modified configuration may be represented outside DNA molecule as an enhanced electrostatic interaction with surrounding environment, that may signal the presence of the damaged site toward the repair enzyme. Work on the DNA strand break shows that open valences at broken strand ends are quickly filled by the electrons generated during radiolysis. Results of simulation indicate a local instability of hydrogen bonds between complementary bases. (author)

  4. Radiation damage of DNA. Model for direct ionization of DNA

    International Nuclear Information System (INIS)

    Kobayashi, Kazuo; Tagawa, Seiichi

    2004-01-01

    Current aspects of radiation damage of DNA, particularly induced by the direct effect of radiation, and author's method of pulse radiolysis are described in relation to behavior of ions formed by radiation and active principles to induce the strand break. In irradiation of DNA solution in water, the direct effect of radiation is derived from ionization of DNA itself and indirect one, from the reaction between DNA and radicals generated from water molecules and the former direct one has been scarcely investigated due to difficulty of experimental approach. Radicals generated in sugar moiety of DNA are shown important in the strand break by recent studies on crystalline DNA irradiated by X-ray, DNA solution by electron and photon beams, hydrated DNA by γ-ray and by high linear energy transfer (LET) ion. Author's pulse radiolysis studies have revealed behaviors of guanine and adenine radical cations in dynamics of DNA oxidation. Since reactions described are the model, the experimental approach is thought necessary for elucidation of the actually occurring DNA damage in living cells. (N.I.)

  5. Characterization of coal fly ash nanoparticles and induced oxidative DNA damage in human peripheral blood mononuclear cells

    International Nuclear Information System (INIS)

    Dwivedi, Sourabh; Saquib, Quaiser; Al-Khedhairy, Abdulaziz A.; Ali, Al-Yousef Sulaiman; Musarrat, Javed

    2012-01-01

    The nano-sized particles present in coal fly ash (CFA) were characterized through the X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) analyses. The XRD data revealed the average crystallite size of the CFA nanoparticles (CFA-NPs) as 14 nm. TEM and SEM imaging demonstrated predominantly spherical and some polymorphic structures in the size range of 11 to 25 nm. The amount of heavy metal associated with CFA particles (μg/g) were determined as Fe (34160.0 ± 1.38), Ni (150.8 ± 0.78), Cu (99.3 ± 0.56) and Cr (64.0 ± 0.86). However, the bioavailability of heavy metals in terms of percent release was in the order as Cr > Ni > Cu > Fe in CFA-dimethyl sulfoxide (DMSO) extract. The comet and cytokinesis blocked micronucleus (CBMN) assays revealed substantial genomic DNA damage in peripheral blood mononuclear (PBMN) cells treated with CFA-NPs in Aq and DMSO extracts. About 1.8 and 3.6 strand breaks per unit of DNA were estimated through alkaline unwinding assay at 1:100 DNA nucleotide/CFA ppm ratios with the Aq and DMSO extracts, respectively. The DNA and mitochondrial damage was invariably greater with CFA-DMSO extract vis-à-vis -Aq extract. Generation of superoxide anions (O 2 • − ) and intracellular reactive oxygen species (ROS) through metal redox-cycling, alteration in mitochondrial potential and 8-oxodG production elucidated CFA-NPs induced oxidative stress as a plausible mechanism for CFA-induced genotoxicity. -- Highlights: ► CFA consists of spherical crystalline nanoparticles in size range of 11–25 nm. ► Alkaline unwinding assay revealed single-strandedness in CFA treated ctDNA. ► CFA nanoparticles exhibited the ability to induce ROS and oxidative DNA damage. ► Comet and CBMN assays revealed DNA and chromosomal breakage in PBMN cells. ► CFA-NPs resulted in mitochondrial membrane damage in PBMN cells.

  6. Characterization of coal fly ash nanoparticles and induced oxidative DNA damage in human peripheral blood mononuclear cells

    Energy Technology Data Exchange (ETDEWEB)

    Dwivedi, Sourabh; Saquib, Quaiser; Al-Khedhairy, Abdulaziz A. [Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Ali, Al-Yousef Sulaiman [Department of Medical Laboratory Sciences, College of Applied Medical Science, University of Dammam, P.O. Box 1683, Hafr Al Batin-31991 (Saudi Arabia); Musarrat, Javed, E-mail: musarratj1@yahoo.com [Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Department of Agricultural Microbiology, Faculty of Agricultural Sciences, AMU, Aligarh202002 (India)

    2012-10-15

    The nano-sized particles present in coal fly ash (CFA) were characterized through the X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) analyses. The XRD data revealed the average crystallite size of the CFA nanoparticles (CFA-NPs) as 14 nm. TEM and SEM imaging demonstrated predominantly spherical and some polymorphic structures in the size range of 11 to 25 nm. The amount of heavy metal associated with CFA particles ({mu}g/g) were determined as Fe (34160.0 {+-} 1.38), Ni (150.8 {+-} 0.78), Cu (99.3 {+-} 0.56) and Cr (64.0 {+-} 0.86). However, the bioavailability of heavy metals in terms of percent release was in the order as Cr > Ni > Cu > Fe in CFA-dimethyl sulfoxide (DMSO) extract. The comet and cytokinesis blocked micronucleus (CBMN) assays revealed substantial genomic DNA damage in peripheral blood mononuclear (PBMN) cells treated with CFA-NPs in Aq and DMSO extracts. About 1.8 and 3.6 strand breaks per unit of DNA were estimated through alkaline unwinding assay at 1:100 DNA nucleotide/CFA ppm ratios with the Aq and DMSO extracts, respectively. The DNA and mitochondrial damage was invariably greater with CFA-DMSO extract vis-a-vis -Aq extract. Generation of superoxide anions (O{sub 2} Bullet {sup -}) and intracellular reactive oxygen species (ROS) through metal redox-cycling, alteration in mitochondrial potential and 8-oxodG production elucidated CFA-NPs induced oxidative stress as a plausible mechanism for CFA-induced genotoxicity. -- Highlights: Black-Right-Pointing-Pointer CFA consists of spherical crystalline nanoparticles in size range of 11-25 nm. Black-Right-Pointing-Pointer Alkaline unwinding assay revealed single-strandedness in CFA treated ctDNA. Black-Right-Pointing-Pointer CFA nanoparticles exhibited the ability to induce ROS and oxidative DNA damage. Black-Right-Pointing-Pointer Comet and CBMN assays revealed DNA and chromosomal

  7. Changes in markers of oxidative stress and DNA damage in human visceral adipose tissue from subjects with obesity and type 2 diabetes.

    Science.gov (United States)

    Jones, D A; Prior, S L; Barry, J D; Caplin, S; Baxter, J N; Stephens, J W

    2014-12-01

    In the past 30 years, prevalence of obesity has almost trebled resulting in an increased incidence of type 2 diabetes mellitus and other co-morbidities. Visceral adipose tissue is believed to play a vital role, but underlying mechanisms remain unclear. Our aim was to investigate changes in markers of oxidative damage in human visceral adipose tissue to determine levels of oxidative burden that may be attributed to obesity and/or diabetes. Visceral adipose tissue samples from 61 subjects undergoing abdominal surgery grouped as lean, obese and obese with type 2 diabetes mellitus, were examined using 3 different markers of oxidative stress. Malondialdehyde (MDA) concentration was measured as a marker of lipid peroxidation, telomere length and Comet assay as markers of oxidative DNA damage. No significant difference in MDA concentration, telomere length and DNA damage was observed between groups, although longer telomere lengths were seen in the obese with diabetes group compared to the obese group (Pstress and DNA damage was observed in samples from subjects with type 2 diabetes mellitus. Further work is required to investigate this further, however this phenomenon may be due to an up regulation of antioxidant defences in adipose tissue. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. Diphenylmethyl selenocyanate attenuates malachite green induced oxidative injury through antioxidation & inhibition of DNA damage in mice

    Science.gov (United States)

    Das, Jayanta Kumar; Sarkar, Sibani; Hossain, Sk Ugir; Chakraborty, Pramita; Das, Rajat Kumar; Bhattacharya, Sudin

    2013-01-01

    Background & objectives: Malachite green (MG), an environmentally hazardous material, is used as a non permitted food colouring agent, especially in India. Selenium (Se) is an essential nutritional trace element required for animals and humans to guard against oxidative stress induced by xenobiotic compounds of diverse nature. In the present study, the role of the selenium compound diphenylmethyl selenocyanate (DMSE) was assessed on the oxidative stress (OS) induced by a food colouring agent, malachite green (MG) in vivo in mice. Methods: Swiss albino mice (Mus musculus) were intraperitoneally injected with MG at a standardized dose of 100 μg/ mouse for 30 days. DMSE was given orally at an optimum dose of 3 mg/kg b.w. in pre (15 days) and concomitant treatment schedule throughout the experimental period. The parameters viz. ALT, AST, LPO, GSH, GST, SOD, CAT, GPx, TrxR, CA, MN, MI and DNA damage have been evaluated. Results: The DMSE showed its potential to protect against MG induced hepatotoxicity by controlling the serum alanine aminotransferase and aspartate amino transferase (ALT and AST) levels and also ameliorated oxidative stress by modulating hepatic lipid peroxidation and different detoxifying and antioxidative enzymes such as glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and also the selenoenzymes such as glutathione peroxidase (GPx) and thioredoxin reductase (TrxR) and reduced glutathione level which in turn reduced DNA damage. Interpretation & conclusions: The organo-selenium compound DMSE showed significant protection against MG induced heptotoxicity and DNA damage in murine model. Better protection was observed in pretreatment group than in the concomitant group. Further studies need to be done to understand the mechanism of action. PMID:23852297

  9. Quercitrin protects skin from UVB-induced oxidative damage

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yuanqin [Cancer Institute, The First Affiliated Hospital, China Medical University, Shenyang (China); Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Li, Wenqi; Son, Young-Ok; Sun, Lijuan; Lu, Jian; Kim, Donghern; Wang, Xin [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Yao, Hua [Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang (China); Wang, Lei; Pratheeshkumar, Poyil; Hitron, Andrew J. [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Luo, Jia [Department of Internal Medicine, University of Kentucky, 800 Rose Street, Lexington, KY (United States); Gao, Ning [Department of Pharmacognos, College of Pharmacy, 3rd Military Medical University, Chongqing (China); Shi, Xianglin [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Zhang, Zhuo, E-mail: zhuo.zhang@uky.edu [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States)

    2013-06-01

    Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin. - Highlights: • Oxidative stress plays a key role in UV-induced cell and tissue injuries. • Quercitrin decreases ROS generation and restores antioxidants irradiated by UVB. • Quercitrin reduces UVB-irradiated oxidative DNA damage, apoptosis, and inflammation. • Quercitrin functions as an antioxidant against UVB-induced skin injuries.

  10. Quercitrin protects skin from UVB-induced oxidative damage

    International Nuclear Information System (INIS)

    Yin, Yuanqin; Li, Wenqi; Son, Young-Ok; Sun, Lijuan; Lu, Jian; Kim, Donghern; Wang, Xin; Yao, Hua; Wang, Lei; Pratheeshkumar, Poyil; Hitron, Andrew J.; Luo, Jia; Gao, Ning; Shi, Xianglin; Zhang, Zhuo

    2013-01-01

    Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin. - Highlights: • Oxidative stress plays a key role in UV-induced cell and tissue injuries. • Quercitrin decreases ROS generation and restores antioxidants irradiated by UVB. • Quercitrin reduces UVB-irradiated oxidative DNA damage, apoptosis, and inflammation. • Quercitrin functions as an antioxidant against UVB-induced skin injuries

  11. Combustion products of 1,3-butadiene inhibit catalase activity and induce expression of oxidative DNA damage repair enzymes in human bronchial epithelial cells.

    Science.gov (United States)

    Kennedy, Christopher H; Catallo, W James; Wilson, Vincent L; Mitchell, James B

    2009-10-01

    1,3-Butadiene, an important petrochemical, is commonly burned off when excess amounts need to be destroyed. This combustion process produces butadiene soot (BDS), which is composed of a complex mixture of polycyclic aromatic hydrocarbons in particulates ranging in size from enzyme inactivation due to protein amino acid oxidation and (2) induce oxidative DNA damage in NHBE cells. Thus, our aims were to determine the effect of butadiene soot ethanol extract (BSEE) on both enzyme activity and the expression of proteins involved in the repair of oxidative DNA damage. Catalase was found to be sensitive to BDS as catalase activity was potently diminished in the presence of BSEE. Using Western analysis, both the alpha isoform of human 8-oxoguanine DNA glycosylase (alpha-hOGG1) and human apurinic/apyrimidinic endonuclease (APE-1) were shown to be significantly overexpressed as compared to untreated controls after exposure of NHBE cells to BSEE. Our results indicate that BSEE is capable of effectively inactivating the antioxidant enzyme catalase, presumably via oxidation of protein amino acids. The presence of oxidized biomolecules may partially explain the extranuclear fluorescence that is detected when NHBE cells are treated with an organic extract of BDS. Overexpression of both alpha-hOGG1 and APE-1 proteins following treatment of NHBE cells with BSEE suggests that this mixture causes oxidative DNA damage.

  12. FIBER OPTIC BIOSENSOR FOR DNA DAMAGE

    Science.gov (United States)

    This paper describes a fiber optic biosensor for the rapid and sensitive detection of radiation-induced or chemically-induced oxidative DNA damage. The assay is based on the hybridization and temperature-induced dissociation (melting curves) of synthetic oligonucleotides. The...

  13. DNA Damage and Pulmonary Hypertension

    Science.gov (United States)

    Ranchoux, Benoît; Meloche, Jolyane; Paulin, Roxane; Boucherat, Olivier; Provencher, Steeve; Bonnet, Sébastien

    2016-01-01

    Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis. PMID:27338373

  14. Measuring oxidative damage to DNA and its repair with the comet assay.

    Science.gov (United States)

    Collins, Andrew R

    2014-02-01

    Single cell gel electrophoresis, or the comet assay, was devised as a sensitive method for detecting DNA strand breaks, at the level of individual cells. A simple modification, incorporating a digestion of DNA with a lesion-specific endonuclease, makes it possible to measure oxidised bases. With the inclusion of formamidopyrimidine DNA glycosylase to recognise oxidised purines, or Nth (endonuclease III) to detect oxidised pyrimidines, the comet assay has been used extensively in human biomonitoring to monitor oxidative stress, usually in peripheral blood mononuclear cells. There is evidence to suggest that the enzymic approach is more accurate than chromatographic methods, when applied to low background levels of base oxidation. However, there are potential problems of over-estimation (because the enzymes are not completely specific) or under-estimation (failure to detect lesions that are close together). Attempts have been made to improve the inter-laboratory reproducibility of the comet assay. In addition to measuring DNA damage, the assay can be used to monitor the cellular or in vitro repair of strand breaks or oxidised bases. It also has applications in assessing the antioxidant status of cells. In its various forms, the comet assay is now an invaluable tool in human biomonitoring and genotoxicity testing. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Poly(GR) in C9ORF72-Related ALS/FTD Compromises Mitochondrial Function and Increases Oxidative Stress and DNA Damage in iPSC-Derived Motor Neurons.

    Science.gov (United States)

    Lopez-Gonzalez, Rodrigo; Lu, Yubing; Gendron, Tania F; Karydas, Anna; Tran, Helene; Yang, Dejun; Petrucelli, Leonard; Miller, Bruce L; Almeida, Sandra; Gao, Fen-Biao

    2016-10-19

    GGGGCC repeat expansions in C9ORF72 are the most common genetic cause of both ALS and FTD. To uncover underlying pathogenic mechanisms, we found that DNA damage was greater, in an age-dependent manner, in motor neurons differentiated from iPSCs of multiple C9ORF72 patients than control neurons. Ectopic expression of the dipeptide repeat (DPR) protein (GR) 80 in iPSC-derived control neurons increased DNA damage, suggesting poly(GR) contributes to DNA damage in aged C9ORF72 neurons. Oxidative stress was also increased in C9ORF72 neurons in an age-dependent manner. Pharmacological or genetic reduction of oxidative stress partially rescued DNA damage in C9ORF72 neurons and control neurons expressing (GR) 80 or (GR) 80 -induced cellular toxicity in flies. Moreover, interactome analysis revealed that (GR) 80 preferentially bound to mitochondrial ribosomal proteins and caused mitochondrial dysfunction. Thus, poly(GR) in C9ORF72 neurons compromises mitochondrial function and causes DNA damage in part by increasing oxidative stress, revealing another pathogenic mechanism in C9ORF72-related ALS and FTD. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Oxidative stress induction by T-2 toxin causes DNA damage and triggers apoptosis via caspase pathway in human cervical cancer cells

    International Nuclear Information System (INIS)

    Chaudhari, Manjari; Jayaraj, R.; Bhaskar, A.S.B.; Lakshmana Rao, P.V.

    2009-01-01

    T-2 toxin is the most toxic trichothecene and both humans and animals suffer from several pathological conditions after consumption of foodstuffs contaminated with trichothecenes. We investigated the molecular mechanism of T-2 toxin induced cytotoxicity and cell death in HeLa cells. T-2 toxin at LC50 of 10 ng/ml caused time dependent increase in cytotoxicity as assessed by dye uptake, lactatedehydrogenase leakage and MTT assay. The toxin caused generation of reactive oxygen species as early as 30 min followed by significant depletion of glutathione levels and increased lipid peroxidation. The results indicate oxidative stress as underlying mechanism of cytotoxicity. Single stranded DNA damage after T-2 treatment was observed as early as 2 and 4 h by DNA diffusion assay. The cells exhibited apoptotic morphology like condensed chromatin and nuclear fragmentation after 4 h of treatment. Downstream of T-2 induced oxidative stress and DNA damage a time dependent increase in expression level of p53 protein was observed. The increase in Bax/Bcl2 ratio indicated shift in response, in favour of apoptotic process in T-2 toxin treated cells. Western blot analysis showed increase in levels of mitochondrial apoptogenic factors Bax, Bcl-2, cytochrome-c followed by activation of caspases-9, -3 and -7 leading to DNA fragmentation and apoptosis. In addition to caspase-dependent pathway, our results showed involvement of caspase-independent AIF pathway in T-2 induced apoptosis. Broad spectrum caspase inhibitor z-VAD-fmk could partially protect the cells from DNA damage but could not inhibit AIF induced oligonucleosomal DNA fragmentation beyond 4 h. Results of the study clearly show that oxidative stress is the underlying mechanism by which T-2 toxin causes DNA damage and apoptosis.

  17. DNA damage in lens epithelium of cataract patients in vivo and ex vivo.

    Science.gov (United States)

    Øsnes-Ringen, Oyvind; Azqueta, Amaia O; Moe, Morten C; Zetterström, Charlotta; Røger, Magnus; Nicolaissen, Bjørn; Collins, Andrew R

    2013-11-01

    DNA damage has been described in the human cataractous lens epithelium, and oxidative stress generated by UV radiation and endogenous metabolic processes has been suggested to play a significant role in the pathogenesis of cataract. In this study, the aim was to explore the quality and relative quantity of DNA damage in lens epithelium of cataract patients in vivo and after incubation in a cell culture system. Capsulotomy specimens were analysed, before and after 1 week of ex vivo cultivation, using the comet assay to measure DNA strand breaks, oxidized purine and pyrimidine bases and UV-induced cyclobutane pyrimidine dimers. DNA strand breaks were barely detectable, oxidized pyrimidines and pyrimidine dimers were present at low levels, whereas there was a relatively high level of oxidized purines, which further increased after cultivation. The observed levels of oxidized purines in cataractous lens epithelium may support a theory consistent with light damage and oxidative stress as mediators of molecular damage to the human lens epithelium. Damage commonly associated with UV-B irradiation was relatively low. The levels of oxidized purines increased further in a commonly used culture system. This is of interest considering the importance and versatility of ex vivo systems in studies exploring the pathogenesis of cataract. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  18. Polychlorinated biphenyl quinone induces oxidative DNA damage and repair responses: The activations of NHEJ, BER and NER via ATM-p53 signaling axis

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Hui; Shi, Qiong; Song, Xiufang; Fu, Juanli; Hu, Lihua; Xu, Demei; Su, Chuanyang; Xia, Xiaomin; Song, Erqun; Song, Yang, E-mail: songyangwenrong@hotmail.com

    2015-07-01

    Our previous studies demonstrated that polychlorinated biphenyl (PCB) quinone induced oxidative DNA damage in HepG2 cells. To promote genomic integrity, DNA damage response (DDR) coordinates cell-cycle transitions, DNA repair and apoptosis. PCB quinone-induced cell cycle arrest and apoptosis have been documented, however, whether PCB quinone insult induce DNA repair signaling is still unknown. In this study, we identified the activation of DDR and corresponding signaling events in HepG2 cells upon the exposure to a synthetic PCB quinone, PCB29-pQ. Our data illustrated that PCB29-pQ induces the phosphorylation of p53, which was mediated by ataxia telangiectasia mutated (ATM) protein kinase. The observed phosphorylated histone H2AX (γ-H2AX) foci and the elevation of 8-hydroxy-2′-deoxyguanosine (8-OHdG) indicated that DDR was stimulated by PCB29-pQ treatment. Additionally, we found PCB29-pQ activates non-homologous end joining (NHEJ), base excision repair (BER) and nucleotide excision repair (NER) signalings. However, these repair pathways are not error-free processes and aberrant repair of DNA damage may cause the potential risk of carcinogenesis and mutagenesis. - Highlights: • Polychlorinated biphenyl quinone induces oxidative DNA damage in HepG2 cells. • The elevation of γ-H2AX and 8-OHdG indicates the activation of DNA damage response. • ATM-p53 signaling acts as the DNA damage sensor and effector. • Polychlorinated biphenyl quinone activates NHEJ, BER and NER signalings.

  19. DNA damage and autophagy

    International Nuclear Information System (INIS)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Panayiotidis, Mihalis I.; Franco, Rodrigo

    2011-01-01

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  20. Grape juice concentrate prevents oxidative DNA damage in peripheral blood cells of rats subjected to a high-cholesterol diet.

    Science.gov (United States)

    Aguiar, Odair; Gollücke, Andréa Pittelli Boiago; de Moraes, Bárbara Bueno; Pasquini, Gabriela; Catharino, Rodrigo Ramos; Riccio, Maria Francesca; Ihara, Silvia Saiuli Miki; Ribeiro, Daniel Araki

    2011-03-01

    The goal of the present study was to investigate whether subchronic treatment with grape juice concentrate is able to protect liver and peripheral blood cells against cholesterol-induced injury in rats. The effects of the grape juice concentrate treatment on histopathological changes, immunohistochemistry for cyclo-oxygenase-2 (COX-2), and basal and oxidative DNA damage induced by H2O2 using a single-cell gel (comet) assay were evaluated. Male Wistar rats (n 18) were divided into three groups: group 1--negative control; group 2--cholesterol at 1 % (w/w) in their diet, treated for 5 weeks; group 3--cholesterol at 1 % in their chow, treated for 5 weeks, and grape juice concentrate at 222 mg/d in their drinking-water in the final week only. The results indicated that the treatment with grape juice concentrate did not show remarkable differences regarding liver tissue in group 3 compared with group 2. However, grape juice concentrate was able to decrease oxidative DNA damage induced by H2O2 in peripheral blood cells, as depicted by the tail moment results. COX-2 expression in the liver did not show statistically significant differences (P>0·05) between groups. Taken together, the present results suggest that the administration of subchronic grape juice concentrate prevents oxidative DNA damage in peripheral blood cells.

  1. Characterization of oxidative guanine damage and repair in mammalian telomeres.

    Directory of Open Access Journals (Sweden)

    Zhilong Wang

    2010-05-01

    Full Text Available 8-oxo-7,8-dihydroguanine (8-oxoG and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG are among the most common oxidative DNA lesions and are substrates for 8-oxoguanine DNA glycosylase (OGG1-initiated DNA base excision repair (BER. Mammalian telomeres consist of triple guanine repeats and are subject to oxidative guanine damage. Here, we investigated the impact of oxidative guanine damage and its repair by OGG1 on telomere integrity in mice. The mouse cells were analyzed for telomere integrity by telomere quantitative fluorescence in situ hybridization (telomere-FISH, by chromosome orientation-FISH (CO-FISH, and by indirect immunofluorescence in combination with telomere-FISH and for oxidative base lesions by Fpg-incision/Southern blot assay. In comparison to the wild type, telomere lengthening was observed in Ogg1 null (Ogg1(-/- mouse tissues and primary embryonic fibroblasts (MEFs cultivated in hypoxia condition (3% oxygen, whereas telomere shortening was detected in Ogg1(-/- mouse hematopoietic cells and primary MEFs cultivated in normoxia condition (20% oxygen or in the presence of an oxidant. In addition, telomere length abnormalities were accompanied by altered telomere sister chromatid exchanges, increased telomere single- and double-strand breaks, and preferential telomere lagging- or G-strand losses in Ogg1(-/- mouse cells. Oxidative guanine lesions were increased in telomeres in Ogg1(-/- mice with aging and primary MEFs cultivated in 20% oxygen. Furthermore, oxidative guanine lesions persisted at high level in Ogg1(-/- MEFs after acute exposure to hydrogen peroxide, while they rapidly returned to basal level in wild-type MEFs. These findings indicate that oxidative guanine damage can arise in telomeres where it affects length homeostasis, recombination, DNA replication, and DNA breakage repair. Our studies demonstrate that BER pathway is required in repairing oxidative guanine damage in telomeres and maintaining telomere integrity

  2. Quantitative analysis of gene-specific DNA damage in human spermatozoa

    International Nuclear Information System (INIS)

    Sawyer, Dennis E.; Mercer, Belinda G.; Wiklendt, Agnieszka M.; Aitken, R. John

    2003-01-01

    Recent studies have suggested that human spermatozoa are highly susceptible to DNA damage induced by oxidative stress. However, a detailed analysis of the precise nature of this damage and the extent to which it affects the mitochondrial and nuclear genomes has not been reported. To induce DNA damage, human spermatozoa were treated in vitro with hydrogen peroxide (H 2 O 2 ; 0-5 mM) or iron (as Fe(II)SO 4 , 0-500 μM). Quantitative PCR (QPCR) was used to measure DNA damage in individual nuclear genes (hprt, β-pol and β-globin) and mitochondrial DNA. Single strand breaks were also assessed by alkaline gel electrophoresis. H 2 O 2 was found to be genotoxic toward spermatozoa at concentrations as high as 1.25 mM, but DNA damage was not detected in these cells with lower concentrations of H 2 O 2 . The mitochondrial genome of human spermatozoa was significantly (P 2 O 2 -induced DNA damage than the nuclear genome. However, both nDNA and mtDNA in human spermatozoa were significantly (P<0.001) more resistant to damage than DNA from a variety of cell lines of germ cell and myoblastoid origin. Interestingly, significant DNA damage was also not detected in human spermatozoa treated with iron. These studies report, for the first time, quantitative measurements of DNA damage in specific genes of male germ cells, and challenge the commonly held belief that human spermatozoa are particularly vulnerable to DNA damage

  3. Associations of neonatal lead, cadmium, chromium and nickel co-exposure with DNA oxidative damage in an electronic waste recycling town

    International Nuclear Information System (INIS)

    Ni, Wenqing; Huang, Yue; Wang, Xiaoling; Zhang, Jingwen; Wu, Kusheng

    2014-01-01

    Objective: This study aimed to evaluate the effects of toxic heavy metal co-exposure on DNA oxidative damage in neonates from a primitive e-waste recycling region, Guiyu town, China. Methods: Our participants included 201 pregnant women: 126 from Guiyu town and 75 from Jinping district of Shantou city, where no e-waste recycling and dismantling activities existed. Structured interview questionnaires were administered to the pregnant women and umbilical cord blood (UCB) samples were collected after delivery. The UCB concentrations of lead, cadmium, chromium, and nickel were analyzed by graphite furnace atomic absorption spectrometry (GFAAS). Levels of UCB plasma 8-hydroxydeoxyguanosine (8-OHdG, a DNA oxidative damage biomarker) were determined by enzyme-linked immunosorbent assay. Results: Our results suggested that UCB lead and cadmium concentrations in neonates of Guiyu were significantly higher than those of Jinping (lead: median 110.45 ng/mL vs. 57.31 ng/mL; cadmium: median 2.50 ng/mL vs. 0.33 ng/mL, both P < 0.001). Parents' residence in Guiyu, and parents' work related to e-waste recycling were the risk factors associated with neonate's UCB lead and cadmium levels. No significant difference of UCB plasma 8-OHdG levels was found between Guiyu and the control area. After adjusting for potential confounders, cord plasma 8-OHdG concentrations (ng/mL) were positively associated with blood cadmium (β = 0.126 ng/mL, 95% CI: 0.055 to 0.198 ng/mL), chromium (β = 0.086 ng/mL, 95% CI: 0.014 to 0.158 ng/mL) and nickel (β = 0.215 ng/mL, 95% CI: 0.113 to 0.317 ng/mL) concentrations. Conclusions: The primitive e-waste recycling and dismantling activities may contribute to the elevated umbilical cord blood toxic heavy metal levels in neonates born in Guiyu. Exposures to cadmium, chromium and nickel were associated with increased oxidative DNA damage in neonates. - Highlights: • DNA oxidative damage levels (8-OHdG) in neonates from Guiyu were assessed. • Neonatal lead

  4. Associations of neonatal lead, cadmium, chromium and nickel co-exposure with DNA oxidative damage in an electronic waste recycling town

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Wenqing; Huang, Yue; Wang, Xiaoling; Zhang, Jingwen; Wu, Kusheng, E-mail: kswu@stu.edu.cn

    2014-02-01

    Objective: This study aimed to evaluate the effects of toxic heavy metal co-exposure on DNA oxidative damage in neonates from a primitive e-waste recycling region, Guiyu town, China. Methods: Our participants included 201 pregnant women: 126 from Guiyu town and 75 from Jinping district of Shantou city, where no e-waste recycling and dismantling activities existed. Structured interview questionnaires were administered to the pregnant women and umbilical cord blood (UCB) samples were collected after delivery. The UCB concentrations of lead, cadmium, chromium, and nickel were analyzed by graphite furnace atomic absorption spectrometry (GFAAS). Levels of UCB plasma 8-hydroxydeoxyguanosine (8-OHdG, a DNA oxidative damage biomarker) were determined by enzyme-linked immunosorbent assay. Results: Our results suggested that UCB lead and cadmium concentrations in neonates of Guiyu were significantly higher than those of Jinping (lead: median 110.45 ng/mL vs. 57.31 ng/mL; cadmium: median 2.50 ng/mL vs. 0.33 ng/mL, both P < 0.001). Parents' residence in Guiyu, and parents' work related to e-waste recycling were the risk factors associated with neonate's UCB lead and cadmium levels. No significant difference of UCB plasma 8-OHdG levels was found between Guiyu and the control area. After adjusting for potential confounders, cord plasma 8-OHdG concentrations (ng/mL) were positively associated with blood cadmium (β = 0.126 ng/mL, 95% CI: 0.055 to 0.198 ng/mL), chromium (β = 0.086 ng/mL, 95% CI: 0.014 to 0.158 ng/mL) and nickel (β = 0.215 ng/mL, 95% CI: 0.113 to 0.317 ng/mL) concentrations. Conclusions: The primitive e-waste recycling and dismantling activities may contribute to the elevated umbilical cord blood toxic heavy metal levels in neonates born in Guiyu. Exposures to cadmium, chromium and nickel were associated with increased oxidative DNA damage in neonates. - Highlights: • DNA oxidative damage levels (8-OHdG) in neonates from Guiyu were assessed.

  5. Alkaline Comet Assay for Assessing DNA Damage in Individual Cells.

    Science.gov (United States)

    Pu, Xinzhu; Wang, Zemin; Klaunig, James E

    2015-08-06

    Single-cell gel electrophoresis, commonly called a comet assay, is a simple and sensitive method for assessing DNA damage at the single-cell level. It is an important technique in genetic toxicological studies. The comet assay performed under alkaline conditions (pH >13) is considered the optimal version for identifying agents with genotoxic activity. The alkaline comet assay is capable of detecting DNA double-strand breaks, single-strand breaks, alkali-labile sites, DNA-DNA/DNA-protein cross-linking, and incomplete excision repair sites. The inclusion of digestion of lesion-specific DNA repair enzymes in the procedure allows the detection of various DNA base alterations, such as oxidative base damage. This unit describes alkaline comet assay procedures for assessing DNA strand breaks and oxidative base alterations. These methods can be applied in a variety of cells from in vitro and in vivo experiments, as well as human studies. Copyright © 2015 John Wiley & Sons, Inc.

  6. PARP-1: Friend or Foe of DNA Damage and Repair in Tumorigenesis?

    Energy Technology Data Exchange (ETDEWEB)

    Swindall, Amanda F.; Stanley, Jennifer A. [Department of Radiation Oncology Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, 176F HSROC Suite 2232B, 1700 6th Avenue South, Birmingham, AL 35249 (United States); Yang, Eddy S., E-mail: eyang@uab.edu [Department of Radiation Oncology Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, 176F HSROC Suite 2232B, 1700 6th Avenue South, Birmingham, AL 35249 (United States); Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35249 (United States); Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35249 (United States)

    2013-07-26

    Oxidative stress induced by reactive oxygen species can result in DNA damage within cells and subsequently increase risk for carcinogenesis. This may be averted by repair of DNA damage through the base or nucleotide excision repair (BER/NER) pathways. PARP, a BER protein, is known for its role in DNA-repair. However, multiple lesions can occur within a small range of DNA, known as oxidative clustered DNA lesions (OCDLs), which are difficult to repair and may lead to the more severe DNA double-strand break (DSB). Inefficient DSB repair can then result in increased mutagenesis and neoplastic transformation. OCDLs occur more frequently within a variety of tumor tissues. Interestingly, PARP is highly expressed in several human cancers. Additionally, chronic inflammation may contribute to tumorigenesis through ROS-induced DNA damage. Furthermore, PARP can modulate inflammation through interaction with NFκB and regulating the expression of inflammatory signaling molecules. Thus, the upregulation of PARP may present a double-edged sword. PARP is needed to repair ROS-induced DNA lesions, but PARP expression may lead to increased inflammation via upregulation of NFκB signaling. Here, we discuss the role of PARP in the repair of oxidative damage versus the formation of OCDLs and speculate on the feasibility of PARP inhibition for the treatment and prevention of cancers by exploiting its role in inflammation.

  7. PARP-1: Friend or Foe of DNA Damage and Repair in Tumorigenesis?

    International Nuclear Information System (INIS)

    Swindall, Amanda F.; Stanley, Jennifer A.; Yang, Eddy S.

    2013-01-01

    Oxidative stress induced by reactive oxygen species can result in DNA damage within cells and subsequently increase risk for carcinogenesis. This may be averted by repair of DNA damage through the base or nucleotide excision repair (BER/NER) pathways. PARP, a BER protein, is known for its role in DNA-repair. However, multiple lesions can occur within a small range of DNA, known as oxidative clustered DNA lesions (OCDLs), which are difficult to repair and may lead to the more severe DNA double-strand break (DSB). Inefficient DSB repair can then result in increased mutagenesis and neoplastic transformation. OCDLs occur more frequently within a variety of tumor tissues. Interestingly, PARP is highly expressed in several human cancers. Additionally, chronic inflammation may contribute to tumorigenesis through ROS-induced DNA damage. Furthermore, PARP can modulate inflammation through interaction with NFκB and regulating the expression of inflammatory signaling molecules. Thus, the upregulation of PARP may present a double-edged sword. PARP is needed to repair ROS-induced DNA lesions, but PARP expression may lead to increased inflammation via upregulation of NFκB signaling. Here, we discuss the role of PARP in the repair of oxidative damage versus the formation of OCDLs and speculate on the feasibility of PARP inhibition for the treatment and prevention of cancers by exploiting its role in inflammation

  8. Antioxidant-mediated up-regulation of OGG1 via NRF2 induction is associated with inhibition of oxidative DNA damage in estrogen-induced breast cancer

    International Nuclear Information System (INIS)

    Singh, Bhupendra; Chatterjee, Anwesha; Ronghe, Amruta M; Bhat, Nimee K; Bhat, Hari K

    2013-01-01

    Estrogen metabolism-mediated oxidative stress is suggested to play an important role in estrogen-induced breast carcinogenesis. We have earlier demonstrated that antioxidants, vitamin C (Vit C) and butylated hydroxyanisole (BHA) inhibit 17β-estradiol (E2)-mediated oxidative stress and oxidative DNA damage, and breast carcinogenesis in female August Copenhagen Irish (ACI) rats. The objective of the present study was to characterize the mechanism by which above antioxidants prevent DNA damage during breast carcinogenesis. Female ACI rats were treated with E2; Vit C; Vit C + E2; BHA; and BHA + E2 for up to 240 days. mRNA and protein levels of a DNA repair enzyme 8-Oxoguanine DNA glycosylase (OGG1) and a transcription factor NRF2 were quantified in the mammary and mammary tumor tissues of rats after treatment with E2 and compared with that of rats treated with antioxidants either alone or in combination with E2. The expression of OGG1 was suppressed in mammary tissues and in mammary tumors of rats treated with E2. Expression of NRF2 was also significantly suppressed in E2-treated mammary tissues and in mammary tumors. Vitamin C or BHA treatment prevented E2-mediated decrease in OGG1 and NRF2 levels in the mammary tissues. Chromatin immunoprecipitation analysis confirmed that antioxidant-mediated induction of OGG1 was through increased direct binding of NRF2 to the promoter region of OGG1. Studies using silencer RNA confirmed the role of OGG1 in inhibition of oxidative DNA damage. Our studies suggest that antioxidants Vit C and BHA provide protection against oxidative DNA damage and E2-induced mammary carcinogenesis, at least in part, through NRF2-mediated induction of OGG1

  9. Induction of oxidative DNA damage by mesalamine in the presence of copper: A potential mechanism for mesalamine anticancer activity

    International Nuclear Information System (INIS)

    Zimmerman, Ryan P.; Jia, Zhenquan; Zhu, Hong; Vandjelovic, Nathan; Misra, Hara P.; Wang, Jianmin; Li, Yunbo

    2011-01-01

    Mesalamine is the first line pharmacologic intervention for patients with ulcerative colitis, and recent epidemiologic studies have demonstrated a protective association between therapeutic use of the drug and colorectal carcinoma. However, the mechanism by which this protection is afforded has yet to be elucidated. Because copper is found at higher than normal concentrations in neoplastic cell nuclei and is known to interact with phenolic compounds to generate reactive oxygen species, we investigated whether the reaction of mesalamine/copper was able to induce oxidative DNA strand breaks in φX-174 RF I plasmid DNA, and the various components of the mechanism by which the reaction occurred. Plasmid DNA strand breaks were induced by pharmacologically relevant concentrations of mesalamine in the presence of a micromolar concentration of Cu(II), and damage was inhibited by bathocuproinedisulfonic acid (BCS) and catalase. Further, we showed that the reaction of copper with mesalamine consumed molecular oxygen, which was inhibited by BCS. Electron paramagnetic resonance spectral analysis of the reaction of copper/mesalamine indicated the presence of the hydroxyl radical, which was inhibited by both BCS and catalase. This study demonstrates for the first time that through a copper-redox cycling mechanism, the copper-mediated oxidation of mesalamine is a pro-oxidant interaction that generates hydroxyl radicals which may participate in oxidative DNA damage. These results demonstrate a potential mechanism of the anticancer effects of mesalamine in patients with ulcerative colitis.

  10. Modification of lymphocyte DNA damage by carotenoid supplementation in postmenopausal women.

    Science.gov (United States)

    Zhao, Xianfeng; Aldini, Giancarlo; Johnson, Elizabeth J; Rasmussen, Helen; Kraemer, Klaus; Woolf, Herb; Musaeus, Nina; Krinsky, Norman I; Russell, Robert M; Yeum, Kyung-Jin

    2006-01-01

    Oxidative stress has been implicated in the pathogenesis of chronic diseases related to aging such as cancer and cardiovascular disease. Carotenoids could be a part of a protective strategy to minimize oxidative damage in vulnerable populations, such as the elderly. Our aim was to determine the protective effect of carotenoids against DNA damage. A randomized, double-blind, placebo-controlled intervention study was conducted. Thirty-seven healthy, nonsmoking postmenopausal women aged 50-70 y were randomly assigned to 1 of 5 groups and were instructed to consume a daily dose of mixed carotenoids (beta-carotene, lutein, and lycopene; 4 mg each), 12 mg of a single carotenoid (beta-carotene, lutein, or lycopene), or placebo for 56 d. Plasma carotenoid concentrations were analyzed by using HPLC, and lymphocyte DNA damage was measured by using a single-cell gel electrophoresis (comet) assay. At day 57, all carotenoid-supplemented groups showed significantly lower endogenous DNA damage than at baseline (P lutein, beta-carotene, and lycopene), an intake that can be achieved by diet, or a larger dose (12 mg) of individual carotenoids exerts protection against DNA damage.

  11. The results of the lipids peroxidation products on the DNA bases as biological markers of the oxidative stress

    International Nuclear Information System (INIS)

    Falletti, O.

    2007-10-01

    Different ways of DNA damages have been studied, among these ones the direct way of DNA damages formation by the reactive oxygen species (R.O.S.). This way leads to the formation of oxidative DNA damages. In 1990, works have suggested an indirect way of DNA damages formation, the lipids peroxidation. Instead of oxidizing directly DNA, the R.O.S. oxide the lipids present in the cells and their membranes; The products coming from this degradation are able to provoke DNA damages. This way has not been studied very much. The work of this thesis is axed on this DNA theme and lipids peroxidation. In the first chapter, we begin by presenting DNA and the direct way of oxidative damages formation by the R.O.S.Then, we speak about the cell lipids suffering oxidation reactions and the different ways of lipids oxidation. Then, we present how the lipid peroxidation is a source of damages for DNA. (N.C.)

  12. MAP kinase-signaling controls nuclear translocation of tripeptidyl-peptidase II in response to DNA damage and oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Preta, Giulio; Klark, Rainier de; Chakraborti, Shankhamala [Center for Molecular Medicine (CMM), Department of Medicine, Karolinska Institutet, Karolinska University Hospital, 171 76 Stockholm (Sweden); Glas, Rickard, E-mail: rickard.glas@ki.se [Center for Molecular Medicine (CMM), Department of Medicine, Karolinska Institutet, Karolinska University Hospital, 171 76 Stockholm (Sweden)

    2010-08-27

    Research highlights: {yields} Nuclear translocation of TPPII occurs in response to different DNA damage inducers. {yields} Nuclear accumulation of TPPII is linked to ROS and anti-oxidant enzyme levels. {yields} MAPKs control nuclear accumulation of TPPII. {yields} Inhibited nuclear accumulation of TPPII decreases DNA damage-induced {gamma}-H2AX expression. -- Abstract: Reactive oxygen species (ROS) are a continuous hazard in eukaroytic cells by their ability to cause damage to biomolecules, in particular to DNA. Previous data indicated that the cytosolic serine peptidase tripeptidyl-peptidase II (TPPII) translocates into the nucleus of most tumor cell lines in response to {gamma}-irradiation and ROS production; an event that promoted p53 expression as well as caspase-activation. We here observed that nuclear translocation of TPPII was dependent on signaling by MAP kinases, including p38MAPK. Further, this was caused by several types of DNA-damaging drugs, a DNA cross-linker (cisplatinum), an inhibitor of topoisomerase II (etoposide), and to some extent also by nucleoside-analogues (5-fluorouracil, hydroxyurea). In the minority of tumor cell lines where TPPII was not translocated into the nucleus in response to DNA damage we observed reduced intracellular ROS levels, and the expression levels of redox defense systems were increased. Further, treatment with the ROS-inducer {gamma}-hexa-chloro-cyclohexane ({gamma}-HCH, lindane), an inhibitor of GAP junctions, restored nuclear translocation of TPPII in these cell lines upon {gamma}-irradiation. Moreover, blocking nuclear translocation of TPPII in etoposide-treated cells, by using a peptide-derived inhibitor (Z-Gly-Leu-Ala-OH), attenuated expression of {gamma}-H2AX in {gamma}-irradiated melanoma cells. Our results indicated a role for TPPII in MAPK-dependent DNA damage signaling.

  13. Analysis of the relationships between oxidative stress, DNA damage and sperm vitality in a patient population: development of diagnostic criteria.

    Science.gov (United States)

    Aitken, R John; De Iuliis, Geoffry N; Finnie, Jane M; Hedges, Andrew; McLachlan, Robert I

    2010-10-01

    DNA damage in human spermatozoa is known to be associated with a variety of adverse clinical outcomes affecting both reproductive efficiency and the health and wellbeing of the offspring. However, the origin of this damage, its biochemical nature and strategies for its amelioration, still await resolution. Using novel methods to simultaneously assess DNA fragmentation (modified TUNEL assay), DNA-base adduct formation (8-hydroxy-2'-deoxyguanosine [8OHdG]) and cell vitality, spermatozoa from a cohort of 50 assisted conception patients were examined and compared with a group of donors. Receiver operating characteristic (ROC) curve analysis was then used to examine the frequency distribution of the data and to determine optimized thresholds for identifying patients exhibiting abnormally high levels of DNA damage. 8OHdG formation and DNA fragmentation were highly correlated with each other and frequently associated with cell death. Percoll centrifugation improved sperm quality but, unexpectedly, increased 8OHdG formation in live cells, as did sperm fractionation using Puresperm gradients. ROC analysis indicated that the frequency distribution of 8OHdG and DNA fragmentation data were significantly different between patients and donors (P live cells. However, the development of novel methods and optimized thresholds for diagnosing oxidative DNA damage in human spermatozoa should assist in the clinical management of this pathology.

  14. Butachlor induced dissipation of mitochondrial membrane potential, oxidative DNA damage and necrosis in human peripheral blood mononuclear cells

    International Nuclear Information System (INIS)

    Dwivedi, Sourabh; Saquib, Quaiser; Al-Khedhairy, Abdulaziz A.; Musarrat, Javed

    2012-01-01

    Highlights: ► Butachlor exhibited strong binding affinity with DNA and produced 8-oxodG adducts. ► Butachlor induced DNA strand breaks and micronuclei formation in PBMN cells. ► Butachlor induced ROS and dissipation of mitochondrial membrane potential in cells. ► Butachlor resulted in cell cycle arrest and eventually caused cellular necrosis. -- Abstract: Butachlor is a systemic herbicide widely applied on rice, tea, wheat, beans and other crops; however, it concurrently exerts toxic effects on beneficial organisms like earthworms, aquatic invertebrates and other non-target animals including humans. Owing to the associated risk to humans, this chloroacetanilide class of herbicide was investigated with the aim to assess its potential for the (i) interaction with DNA, (ii) mitochondria membrane damage and DNA strand breaks and (iii) cell cycle arrest and necrosis in butachlor treated human peripheral blood mononuclear (PBMN) cells. Fluorescence quenching data revealed the binding constant (Ka = 1.2 × 10 4 M −1 ) and binding capacity (n = 1.02) of butachlor with ctDNA. The oxidative potential of butachlor was ascertained based on its capacity of inducing reactive oxygen species (ROS) and substantial amounts of promutagenic 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) adducts in DNA. Also, the discernible butachlor dose-dependent reduction in fluorescence intensity of a cationic dye rhodamine (Rh-123) and increased fluorescence intensity of 2′,7′-dichlorodihydro fluorescein diacetate (DCFH-DA) in treated cells signifies decreased mitochondrial membrane potential (ΔΨm) due to intracellular ROS generation. The comet data revealed significantly greater Olive tail moment (OTM) values in butachlor treated PBMN cells vs untreated and DMSO controls. Treatment of cultured PBMN cells for 24 h resulted in significantly increased number of binucleated micronucleated (BNMN) cells with a dose dependent reduction in the nuclear division index (NDI). The flow

  15. No effect of 600 grams fruit and vegetables per day on oxidative DNA damage and repair in healthy nonsmokers

    DEFF Research Database (Denmark)

    Moller, P.; Vogel, Ulla Birgitte; Pedersen, A.

    2003-01-01

    In several epidemiological studies, high intakes of fruits and vegetables have been associated with a lower incidence of cancer. Theoretically, intake of antioxidants by consumption of fruits and vegetables should protect against reactive oxygen species and decrease the formation of oxidative DNA...... consumed. Our results show that after 24 days of complete depletion of fruits and vegetables, or daily ingestion of 600 g of fruit and vegetables, or the corresponding amount of vitamins and minerals, the level of oxidative DNA damage was unchanged. This suggests that the inherent antioxidant defense...... damage. We set up a parallel 24-day dietary placebo-controlled intervention study in which 43 subjects were randomized into three groups receiving an antioxidant-free basal diet and 600 g of fruits and vegetables, or a supplement containing the corresponding amounts of vitamins and minerals, or placebo...

  16. Associations of neonatal lead, cadmium, chromium and nickel co-exposure with DNA oxidative damage in an electronic waste recycling town.

    Science.gov (United States)

    Ni, Wenqing; Huang, Yue; Wang, Xiaoling; Zhang, Jingwen; Wu, Kusheng

    2014-02-15

    This study aimed to evaluate the effects of toxic heavy metal co-exposure on DNA oxidative damage in neonates from a primitive e-waste recycling region, Guiyu town, China. Our participants included 201 pregnant women: 126 from Guiyu town and 75 from Jinping district of Shantou city, where no e-waste recycling and dismantling activities existed. Structured interview questionnaires were administered to the pregnant women and umbilical cord blood (UCB) samples were collected after delivery. The UCB concentrations of lead, cadmium, chromium, and nickel were analyzed by graphite furnace atomic absorption spectrometry (GFAAS). Levels of UCB plasma 8-hydroxydeoxyguanosine (8-OHdG, a DNA oxidative damage biomarker) were determined by enzyme-linked immunosorbent assay. Our results suggested that UCB lead and cadmium concentrations in neonates of Guiyu were significantly higher than those of Jinping (lead: median 110.45 ng/mL vs. 57.31 ng/mL; cadmium: median 2.50 ng/mL vs. 0.33 ng/mL, both Pnickel (β=0.215 ng/mL, 95% CI: 0.113 to 0.317 ng/mL) concentrations. The primitive e-waste recycling and dismantling activities may contribute to the elevated umbilical cord blood toxic heavy metal levels in neonates born in Guiyu. Exposures to cadmium, chromium and nickel were associated with increased oxidative DNA damage in neonates. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Ursolic Acid-Regulated Energy Metabolism—Reliever or Propeller of Ultraviolet-Induced Oxidative Stress and DNA Damage?

    Directory of Open Access Journals (Sweden)

    Yuan-Hao Lee

    2014-08-01

    sensitizer, ursolic acid (UA, which results in the metabolic adaptation of normal cells against UV-induced ROS, and the metabolic switch of tumor cells subject to UV-induced damage. The multifaceted natural compound, UA, specifically inhibits photo-oxidative DNA damage in retinal pigment epithelial cells while enhancing that in skin melanoma. Considering the UA-mediated differential effects on cell bioenergetics, this article reviews the disparities in glucose metabolism between tumor and normal cells, along with (peroxisome proliferator-activated receptor-γ coactivator 1α-dependent mitochondrial metabolism and redox (reduction-oxidation control to demonstrate UA-induced synthetic lethality in tumor cells.

  18. Bisphenol A induces oxidative stress and DNA damage in hepatic tissue of female rat offspring

    Directory of Open Access Journals (Sweden)

    Jehane I. Eid

    2015-08-01

    Full Text Available Bisphenol A (BPA is an endocrine disrupting compound widely spread in our living environment. It is a contaminant with increasing exposure to it and exerts both toxic and estrogenic effects on mammalian cells. Due to the limited information concerning the effect of BPA on the liver, the present study was designed to assess hepatic tissue injury induced by early life exposure to BPA in female rat offspring. Rat dams (n = 9 were gavaged with 0.5 and 50 mg of BPA/kg b.w./day throughout lactation until weaning. The sham group received olive oil for the same duration while the control group did not receive any injection. The liver tissue was collected from female pups at different pubertal periods (PND50, 90 and 110 to evaluate oxidative stress biomarkers, extent of DNA damage and histopathological changes. Our results indicated that early life exposure to BPA significantly increased oxidative/nitrosative stress, decreased antioxidant enzyme activities, induced DNA damage and chronic severe inflammation in the hepatic tissue in a time dependent manner. These data suggested that BPA causes long-term adverse effects on the liver, which leads to deleterious effects in the liver of female rat offspring.

  19. Glutathione-deficient Plasmodium berghei parasites exhibit growth delay and nuclear DNA damage.

    Science.gov (United States)

    Padín-Irizarry, Vivian; Colón-Lorenzo, Emilee E; Vega-Rodríguez, Joel; Castro, María Del R; González-Méndez, Ricardo; Ayala-Peña, Sylvette; Serrano, Adelfa E

    2016-06-01

    Plasmodium parasites are exposed to endogenous and exogenous oxidative stress during their complex life cycle. To minimize oxidative damage, the parasites use glutathione (GSH) and thioredoxin (Trx) as primary antioxidants. We previously showed that disruption of the Plasmodium berghei gamma-glutamylcysteine synthetase (pbggcs-ko) or the glutathione reductase (pbgr-ko) genes resulted in a significant reduction of GSH in intraerythrocytic stages, and a defect in growth in the pbggcs-ko parasites. In this report, time course experiments of parasite intraerythrocytic development and morphological studies showed a growth delay during the ring to schizont progression. Morphological analysis shows a significant reduction in size (diameter) of trophozoites and schizonts with increased number of cytoplasmic vacuoles in the pbggcs-ko parasites in comparison to the wild type (WT). Furthermore, the pbggcs-ko mutants exhibited an impaired response to oxidative stress and increased levels of nuclear DNA (nDNA) damage. Reduced GSH levels did not result in mitochondrial DNA (mtDNA) damage or protein carbonylations in neither pbggcs-ko nor pbgr-ko parasites. In addition, the pbggcs-ko mutant parasites showed an increase in mRNA expression of genes involved in oxidative stress detoxification and DNA synthesis, suggesting a potential compensatory mechanism to allow for parasite proliferation. These results reveal that low GSH levels affect parasite development through the impairment of oxidative stress reduction systems and damage to the nDNA. Our studies provide new insights into the role of the GSH antioxidant system in the intraerythrocytic development of Plasmodium parasites, with potential translation into novel pharmacological interventions. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Mgm101p is a novel component of the mitochondrial nucleoid that binds DNA and is required for the repair of oxidatively damaged mitochondrial DNA

    International Nuclear Information System (INIS)

    Meeusen, S.; Tieu, Q.; Wong, E.; Weiss, E.; Schieltz, D.; Yates, J.R.; Nunnari, J.

    1999-01-01

    Maintenance of mitochondrial DNA (mtDNA) during cell division is required for progeny to be respiratory competent. Maintenance involves the replication, repair, assembly, segregation, and partitioning of the mitochondrial nucleoid. MGM101 has been identified as a gene essential for mtDNA maintenance in S. cerevisiae, but its role is unknown. Using liquid chromatography coupled with tandem mass spectrometry, we identified Mgm101p as a component of highly enriched nucleoids, suggesting that it plays a nucleoid-specific role in maintenance. Subcellular fractionation, indirect immunofluorescence and GFP tagging show that Mgm101p is exclusively associated with the mitochondrial nucleoid structure in cells. Furthermore, DNA affinity chromatography of nucleoid extracts indicates that Mgm101p binds to DNA, suggesting that its nucleoid localization is in part due to this activity. Phenotypic analysis of cells containing a temperature sensitive mgm101 allele suggests that Mgm101p is not involved in mtDNA packaging, segregation, partitioning or required for ongoing mtDNA replication. We examined Mgm101p's role in mtDNA repair. As compared with wild-type cells, mgm101 cells were more sensitive to mtDNA damage induced by UV irradiation and were hypersensitive to mtDNA damage induced by gamma rays and H2O2 treatment. Thus, we propose that Mgm101p performs an essential function in the repair of oxidatively damaged mtDNA that is required for the maintenance of the mitochondrial genome. (author)

  1. Oxidative Stress and DNA Methylation in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Krishna Vanaja Donkena

    2010-01-01

    Full Text Available The protective effects of fruits, vegetables, and other foods on prostate cancer may be due to their antioxidant properties. An imbalance in the oxidative stress/antioxidant status is observed in prostate cancer patients. Genome oxidative damage in prostate cancer patients is associated with higher lipid peroxidation and lower antioxidant levels. Oxygen radicals are associated with different steps of carcinogenesis, including structural DNA damage, epigenetic changes, and protein and lipid alterations. Epigenetics affects genetic regulation, cellular differentiation, embryology, aging, cancer, and other diseases. DNA methylation is perhaps the most extensively studied epigenetic modification, which plays an important role in the regulation of gene expression and chromatin architecture, in association with histone modification and other chromatin-associated proteins. This review will provide a broad overview of the interplay of oxidative stress and DNA methylation, DNA methylation changes in regulation of gene expression, lifestyle changes for prostate cancer prevention, DNA methylation as biomarkers for prostate cancer, methods for detection of methylation, and clinical application of DNA methylation inhibitors for epigenetic therapy.

  2. Caryocar brasiliense camb protects against genomic and oxidative damage in urethane-induced lung carcinogenesis

    Directory of Open Access Journals (Sweden)

    N.B.R. Colombo

    2015-01-01

    Full Text Available The antioxidant effects of Caryocar brasiliense Camb, commonly known as the pequi fruit, have not been evaluated to determine their protective effects against oxidative damage in lung carcinogenesis. In the present study, we evaluated the role of pequi fruit against urethane-induced DNA damage and oxidative stress in forty 8-12 week old male BALB/C mice. An in vivo comet assay was performed to assess DNA damage in lung tissues and changes in lipid peroxidation and redox cycle antioxidants were monitored for oxidative stress. Prior supplementation with pequi oil or its extract (15 µL, 60 days significantly reduced urethane-induced oxidative stress. A protective effect against DNA damage was associated with the modulation of lipid peroxidation and low protein and gene expression of nitric oxide synthase. These findings suggest that the intake of pequi fruit might protect against in vivo genotoxicity and oxidative stress.

  3. Colorimetric detection of DNA damage by using hemin-graphene nanocomposites

    Science.gov (United States)

    Wei, W.; Zhang, D. M.; Yin, L. H.; Pu, Y. P.; Liu, S. Q.

    2013-04-01

    A colorimetric method for detection of DNA damage was developed by using hemin-graphene nanosheets (H-GNs). H-GNs were skillfully synthesized by adsorping of hemin on graphene through π-π interactions. The as-prepared H-GNs possessed both the ability of graphene to differentiate the damage DNA from intact DNA and the catalytic action of hemin. The damaged DNA made H-GNs coagulated to different degrees from the intact DNA because there were different amount of negative charge exposed on their surface, which made a great impact on the solubility of H-GNs. As a result, the corresponding centrifugal supernatant of H-GNs solution showed different color in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2, which could be discriminated by naked eyes or by ultraviolet (UV)-visible spectrometer. Based on this, the damaged effects of styrene oxide (SO), NaAsO2 and UV radiation on DNA were studied. Results showed that SO exerted most serious damage effect on DNA although all of them damaged DNA seriously. The new method for detection of DNA damage showed good prospect in the evaluation of genotoxicity of new compounds, the maximum limit of pesticide residue, food additives, and so on, which is important in the fields of food science, pharmaceutical science and pesticide science.

  4. Investigation of the induction of oxidative DNA damage by means of an enzyme-linked immunosorbent assay (ELISA) for thymine glycol containing DNA

    International Nuclear Information System (INIS)

    Pohlenz-Michel, C.

    1988-01-01

    The report explains an ELISA test system for the detection and quantification of toxic effects on genes, induced by mutagenic or carcinogenic chemicals introduced by way of reactive oxygen species. Sensitivity and reproducibility are defined, and the system's applicability to the detection of oxidative DNA damage as a result of the metabolism of chemicals in cellular systems is discussed. (TRV) [de

  5. DNA Oncogenic Virus-Induced Oxidative Stress, Genomic Damage, and Aberrant Epigenetic Alterations

    Directory of Open Access Journals (Sweden)

    Mankgopo Magdeline Kgatle

    2017-01-01

    Full Text Available Approximately 20% of human cancers is attributable to DNA oncogenic viruses such as human papillomavirus (HPV, hepatitis B virus (HBV, and Epstein-Barr virus (EBV. Unrepaired DNA damage is the most common and overlapping feature of these DNA oncogenic viruses and a source of genomic instability and tumour development. Sustained DNA damage results from unceasing production of reactive oxygen species and activation of inflammasome cascades that trigger genomic changes and increased propensity of epigenetic alterations. Accumulation of epigenetic alterations may interfere with genome-wide cellular signalling machineries and promote malignant transformation leading to cancer development. Untangling and understanding the underlying mechanisms that promote these detrimental effects remain the major objectives for ongoing research and hope for effective virus-induced cancer therapy. Here, we review current literature with an emphasis on how DNA damage influences HPV, HVB, and EBV replication and epigenetic alterations that are associated with carcinogenesis.

  6. Smoking modify the effects of polycyclic aromatic hydrocarbons exposure on oxidative damage to DNA in coke oven workers.

    Science.gov (United States)

    Yang, Jin; Zhang, Hongjie; Zhang, Huitao; Wang, Wubin; Liu, Yanli; Fan, Yanfeng

    2017-07-01

    Coke oven emissions containing polycyclic aromatic hydrocarbons (PAHs) are predominant toxic constituents of particulate air pollution that have been linked to increased risk of lung cancer. Numerous epidemiological studies have suggested that oxidative DNA damage may play a pivotal role in the carcinogenic mechanism of lung cancer. Little is known about the effect of interaction between PAHs exposure and lifestyle on DNA oxidative damage. The study population is composed by coke oven workers (365) and water treatment workers (144), and their urinary levels of four PAH metabolites and 8-hydroxydeoxyguanosine (8-OHdG) were determined. Airborne samples of exposed sites (4) and control sites (3) were collected, and eight carcinogenic PAHs were detected by high-performance liquid chromatography. The median values of the sum of eight carcinogenic PAHs and BaP in exposed sites were significantly higher than control sites (P < 0.01). The study found that the urinary PAH metabolites were significantly elevated in coke oven workers (P < 0.01). Multivariate logistic regression analysis revealed that the risk of high levels of urinary 8-OHdG will increase with increasing age, cigarette consumption, and levels of urinary 1-hydroxypyrene, and P for trend were all <0.05. Smoking can significantly modify the effects of urinary 1-hydroxypyrene on high concentrations urinary 8-OHdG, during co-exposure to both light or heavy smoking and high 1-hydroxypyrene levels (OR 4.28, 95% CI 1.32-13.86 and OR 5.05, 95% CI 1.63-15.67, respectively). Our findings quantitatively demonstrate that workers exposed to coke oven fumes and smoking will cause more serious DNA oxidative damage.

  7. Role of GSTT1 deletion in DNA oxidative damage by exposure to polycyclic aromatic hydrocarbons in humans

    Czech Academy of Sciences Publication Activity Database

    Garte, S.; Taioli, E.; Popov, T.; Kalina, I.; Šrám, Radim; Farmer, P.

    2007-01-01

    Roč. 120, - (2007), s. 2499-2503 ISSN 0020-7136 Grant - others:EU(GB) 2000-00091 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK Keywords : metabolic polymorphism * GSTT1 genotype * oxidative DNA damage Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.555, year: 2007

  8. Measurement and protection of the oxidative damage induced by high-LET carbon-ion irradiation in salmon sperm DNA solution

    International Nuclear Information System (INIS)

    Moritake, T.; Nose, T.; Tsuboi, K.; Anzai, K.; Ikota, N.; Ozawa, T.; Ando, K.

    2003-01-01

    The aims of this study are to quantify the yield of hydroxyl radicals (OH) , and to evaluate the oxidative damage on DNA after high-linear energy transfer (LET) carbon-ion beams and x-rays. For this purpose, the relationship between the radiolytic yield of OH in aqueous solution and 8-hydroxydeoxyguanosine (8-OHdG) level in DNA solution were assessed after radiation. In addition, the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazonline-5-one (edaravone) on DNA was evaluated. Culture medium containing 200 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was irradiated with doses of 0 to 20 Gy with an LET of 20 to 90 keV/μm, and the yields of OH were measured using an electron spin resonance (ESR) spectrometer. Salmon sperm DNA solution at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-rays or 290 MeV/nucleon carbon-ion beams with an LET range of 20-80 keV/μm. 8-OHdG levels in the DNA solution were measured by HPLC with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations of 10 μM to 1 mM and 8-OHdG levels were measured by the same method after irradiation. The yield of OH by carbon-ion radiolysis increased in proportion to the absorbed dose over the range of 0 to 20 Gy, and the yield of OH decreased as LET increased logarithmically from 20 to 90 keV/μm. The level of 8-OHdG increased dose-dependently after x-ray irradiation, and it was significantly suppressed by edaravone. Furthermore, the yield of 8-OHdG and the protection efficiency by edaravone decreased as LET value increased. These unique findings provide further understanding of the indirect effect of high-LET radiation, and chemical protection of oxidative damage on DNA is important for clinical application of high-LET radiation

  9. Measurement and protection of the oxidative damage induced by high-LET carbon-ion irradiation in salmon sperm DNA solution

    Energy Technology Data Exchange (ETDEWEB)

    Moritake, T; Nose, T [University of Tsukuba, (Japan); Tsuboi, K [Institute of Clinical Medical Center, (Japan); Anzai, K; Ikota, N [National Institute of Radiological Sciences, (Japan); Ozawa, T [Redox Regulation Research Group, (Japan); Ando, K [Research Center of Charged Particle Therapy, (Japan). National Institution

    2003-07-01

    The aims of this study are to quantify the yield of hydroxyl radicals (OH) , and to evaluate the oxidative damage on DNA after high-linear energy transfer (LET) carbon-ion beams and x-rays. For this purpose, the relationship between the radiolytic yield of OH in aqueous solution and 8-hydroxydeoxyguanosine (8-OHdG) level in DNA solution were assessed after radiation. In addition, the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazonline-5-one (edaravone) on DNA was evaluated. Culture medium containing 200 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was irradiated with doses of 0 to 20 Gy with an LET of 20 to 90 keV/{mu}m, and the yields of OH were measured using an electron spin resonance (ESR) spectrometer. Salmon sperm DNA solution at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-rays or 290 MeV/nucleon carbon-ion beams with an LET range of 20-80 keV/{mu}m. 8-OHdG levels in the DNA solution were measured by HPLC with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations of 10 {mu}M to 1 mM and 8-OHdG levels were measured by the same method after irradiation. The yield of OH by carbon-ion radiolysis increased in proportion to the absorbed dose over the range of 0 to 20 Gy, and the yield of OH decreased as LET increased logarithmically from 20 to 90 keV/{mu}m. The level of 8-OHdG increased dose-dependently after x-ray irradiation, and it was significantly suppressed by edaravone. Furthermore, the yield of 8-OHdG and the protection efficiency by edaravone decreased as LET value increased. These unique findings provide further understanding of the indirect effect of high-LET radiation, and chemical protection of oxidative damage on DNA is important for clinical application of high-LET radiation.

  10. Oxidative damage and antioxidant defense in thymus of malnourished lactating rats.

    Science.gov (United States)

    Gavia-García, Graciela; González-Martínez, Haydeé; Miliar-García, Ángel; Bonilla-González, Edmundo; Rosas-Trejo, María de Los Ángeles; Königsberg, Mina; Nájera-Medina, Oralia; Luna-López, Armando; González-Torres, María Cristina

    2015-01-01

    Malnutrition has been associated with oxidative damage by altered antioxidant protection mechanisms. Specifically, the aim of this study was to evaluate oxidative damage (DNA and lipid) and antioxidant status (superoxide dismutase [SOD], glutathione peroxidase [GPx], and catalase [CAT] mRNA, and protein expression) in thymus from malnourished rat pups. Malnutrition was induced during the lactation period by the food competition method. Oxidative DNA damage was determined quantifying 8-oxo-7, 8-dihydro-2'-deoxyguanosine adduct by high-performance liquid chromatography. Lipid peroxidation was assessed by the formation of thiobarbituric acid-reactive substances. Levels of gene and protein expression of SOD, GPx, and CAT were evaluated by real-time polymerase chain reaction and Western blot, respectively. Antioxidant enzyme activities were measured spectrophotometrically. Oxidative DNA damage and lipid peroxidation significantly increased in second-degree (MN-2) and third-degree malnourished (MN-3) rats compared with well-nourished rats. Higher amounts of oxidative damage, lower mRNA expression, and lower relative concentrations of protein, as well as decreased antioxidant activity of SOD, GPx, and CAT were associated with the MN-2 and MN-3 groups. The results of this study demonstrated that higher body-weight deficits were related to alterations in antioxidant protection, which contribute to increased levels of damage in the thymus. To our knowledge, this study demonstrated for the first time that early in life, malnutrition leads to increased DNA and lipid oxidative damage, attributable to damaged antioxidant mechanisms including transcriptional and enzymatic activity alterations. These findings may contribute to the elucidation of the causes of previously reported thymus dysfunction, and might explain partially why children and adults who have overcome child undernourishment experience immunologic deficiencies. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Oxidative Damage to RPA Limits the Nucleotide Excision Repair Capacity of Human Cells.

    Science.gov (United States)

    Guven, Melisa; Brem, Reto; Macpherson, Peter; Peacock, Matthew; Karran, Peter

    2015-11-01

    Nucleotide excision repair (NER) protects against sunlight-induced skin cancer. Defective NER is associated with photosensitivity and a high skin cancer incidence. Some clinical treatments that cause photosensitivity can also increase skin cancer risk. Among these, the immunosuppressant azathioprine and the fluoroquinolone antibiotics ciprofloxacin and ofloxacin interact with UVA radiation to generate reactive oxygen species that diminish NER capacity by causing protein damage. The replication protein A (RPA) DNA-binding protein has a pivotal role in DNA metabolism and is an essential component of NER. The relationship between protein oxidation and NER inhibition was investigated in cultured human cells expressing different levels of RPA. We show here that RPA is limiting for NER and that oxidative damage to RPA compromises NER capability. Our findings reveal that cellular RPA is surprisingly vulnerable to oxidation, and we identify oxidized forms of RPA that are associated with impaired NER. The vulnerability of NER to inhibition by oxidation provides a connection between cutaneous photosensitivity, protein damage, and increased skin cancer risk. Our findings emphasize that damage to DNA repair proteins, as well as to DNA itself, is likely to be an important contributor to skin cancer risk.

  12. DNA damage and polyploidization.

    Science.gov (United States)

    Chow, Jeremy; Poon, Randy Y C

    2010-01-01

    A growing body of evidence indicates that polyploidization triggers chromosomal instability and contributes to tumorigenesis. DNA damage is increasingly being recognized for its roles in promoting polyploidization. Although elegant mechanisms known as the DNA damage checkpoints are responsible for halting the cell cycle after DNA damage, agents that uncouple the checkpoints can induce unscheduled entry into mitosis. Likewise, defects of the checkpoints in several disorders permit mitotic entry even in the presence of DNA damage. Forcing cells with damaged DNA into mitosis causes severe chromosome segregation defects, including lagging chromosomes, chromosomal fragments and chromosomal bridges. The presence of these lesions in the cleavage plane is believed to abort cytokinesis. It is postulated that if cytokinesis failure is coupled with defects of the p53-dependent postmitotic checkpoint pathway, cells can enter S phase and become polyploids. Progress in the past several years has unraveled some of the underlying principles of these pathways and underscored the important role of DNA damage in polyploidization. Furthermore, polyploidization per se may also be an important determinant of sensitivity to DNA damage, thereby may offer an opportunity for novel therapies.

  13. Assessment of DNA damage induced by terrestrial UV irradiation of dried bloodstains: forensic implications.

    Science.gov (United States)

    Hall, Ashley; Sims, Lynn M; Ballantyne, Jack

    2014-01-01

    Few publications have detailed the nature of DNA damage in contemporary (i.e. non-ancient) dried biological stains. The chief concern, from a forensic standpoint, is that the damage can inhibit polymerase-mediated primer extension, ultimately resulting in DNA typing failure. In the work described here, we analyzed the effects of UVA and UVB irradiation on cell-free solubilized DNA, cell-free dehydrated DNA and dehydrated cellular DNA (from bloodstains). After UV exposure ranging from 25 J cm(-2) to 1236 J cm(-2), we assayed for the presence of bipyrimidine photoproducts (BPPPs), oxidative lesions and strand breaks, correlating the damage with the inhibition of STR profiling. Subsequent to irradiation with either UVA and UVB, the incidence of BPPPs, oxidative products and strand breaks were observed in decreasing quantities as follows: cell-free solubilized DNA>cell-free dehydrated DNA>bloodstain DNA. UVA irradiation did not result in even the partial loss of a STR profile in any sample tested. Somewhat different results were observed after genetic analysis of UVB exposed samples, in that the ability to produce a complete STR profile was affected earliest in bloodstain DNA, next in cell-free solubilized DNA and not at all in cell-free dehydrated DNA. Therefore, it is likely that other types of damage contributed to allele-drop-out in these samples but remained undetected by our assays, whereby the endonucleases did not react with the lesions or the presence of the lesions was masked by strand breaks. Under the conditions of the study, strand breaks appeared to be the predominant types of damage that ultimately resulted in DNA typing failure from physiological stains, although some evidence suggested oxidative damage may have played a role as well. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. Increased DNA damage in blood cells of rat treated with lead as assessed by comet assay

    Directory of Open Access Journals (Sweden)

    Mohammad Arif

    2008-06-01

    Full Text Available A growing body of evidence suggests that oxidative stress is the key player in the pathogenesis of lead-induced toxicity. The present study investigated lead induced oxidative DNA damage, if any in rat blood cells by alkaline comet assay. Lead was administered intraperitoneally to rats at doses of 25, 50 and 100 mg/kg body weight for 5 days consecutively. Blood collected on day six from sacrificed lead-treated rats was used to assess the extent of DNA damage by comet assay which entailed measurement of comet length, olive tail moment, tail DNA (% and tail length. The results showed that treatment with lead significantly increased DNA damage in a dose-dependent manner. Therefore, our data suggests that lead treatment is associated with oxidative stress-induced DNA damage in rat blood cells which could be used as an early bio-marker of lead-toxicity.

  15. OGG1 Involvement in High Glucose-Mediated Enhancement of Bupivacaine-Induced Oxidative DNA Damage in SH-SY5Y Cells

    Science.gov (United States)

    Liu, Zhong-Jie; Zhao, Wei; Zhang, Qing-Guo; Li, Le; Lai, Lu-Ying; Jiang, Shan; Xu, Shi-Yuan

    2015-01-01

    Hyperglycemia can inhibit expression of the 8-oxoG-DNA glycosylase (OGG1) which is one of the key repair enzymes for DNA oxidative damage. The effect of hyperglycemia on OGG1 expression in response to local anesthetics-induced DNA damage is unknown. This study was designed to determine whether high glucose inhibits OGG1 expression and aggravates bupivacaine-induced DNA damage via reactive oxygen species (ROS). SH-SY5Y cells were cultured with or without 50 mM glucose for 8 days before they were treated with 1.5 mM bupivacaine for 24 h. OGG1 expression was measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. ROS was estimated using the redox-sensitive fluorescent dye DCFH-DA. DNA damage was investigated with immunostaining for 8-oxodG and comet assays. OGG1 expression was inhibited in cells exposed to high glucose with concomitant increase in ROS production and more severe DNA damage as compared to control culture conditions, and these changes were further exacerbated by bupivacaine. Treatment with the antioxidant N-acetyl-L-cysteine (NAC) prevented high glucose and bupivacaine mediated increase in ROS production and restored functional expression of OGG1, which lead to attenuated high glucose-mediated exacerbation of bupivacaine neurotoxicity. Our findings indicate that subjects with diabetes may experience more detrimental effects following bupivacaine use. PMID:26161242

  16. OGG1 Involvement in High Glucose-Mediated Enhancement of Bupivacaine-Induced Oxidative DNA Damage in SH-SY5Y Cells

    Directory of Open Access Journals (Sweden)

    Zhong-Jie Liu

    2015-01-01

    Full Text Available Hyperglycemia can inhibit expression of the 8-oxoG-DNA glycosylase (OGG1 which is one of the key repair enzymes for DNA oxidative damage. The effect of hyperglycemia on OGG1 expression in response to local anesthetics-induced DNA damage is unknown. This study was designed to determine whether high glucose inhibits OGG1 expression and aggravates bupivacaine-induced DNA damage via reactive oxygen species (ROS. SH-SY5Y cells were cultured with or without 50 mM glucose for 8 days before they were treated with 1.5 mM bupivacaine for 24 h. OGG1 expression was measured by quantitative real-time polymerase chain reaction (qRT-PCR and western blot. ROS was estimated using the redox-sensitive fluorescent dye DCFH-DA. DNA damage was investigated with immunostaining for 8-oxodG and comet assays. OGG1 expression was inhibited in cells exposed to high glucose with concomitant increase in ROS production and more severe DNA damage as compared to control culture conditions, and these changes were further exacerbated by bupivacaine. Treatment with the antioxidant N-acetyl-L-cysteine (NAC prevented high glucose and bupivacaine mediated increase in ROS production and restored functional expression of OGG1, which lead to attenuated high glucose-mediated exacerbation of bupivacaine neurotoxicity. Our findings indicate that subjects with diabetes may experience more detrimental effects following bupivacaine use.

  17. DNA damage by ethylbenzenehydroperoxide formed from carcinogenic ethylbenzene by sunlight irradiation

    International Nuclear Information System (INIS)

    Toda, Chitose; Uchida, Takafumi; Midorikawa, Kaoru; Murata, Mariko; Hiraku, Yusuke; Okamoto, Yoshinori; Ueda, Koji; Kojima, Nakao; Kawanishi, Shosuke

    2003-01-01

    Ethylbenzene, widely used in human life, is a non-mutagenic carcinogen. Sunlight-irradiated ethylbenzene caused DNA damage in the presence of Cu 2+ , but unirradiated ethylbenzene did not. A Cu + -specific chelator bathocuproine inhibited DNA damage and catalase showed a little inhibitory effect. The scopoletin assay revealed that peroxides and H 2 O 2 were formed in ethylbenzene exposed to sunlight. These results suggest that Cu + and alkoxyl radical mainly participate in DNA damage, and H 2 O 2 partially does. When catalase was added, DNA damage at thymine and cytosine was inhibited. Ethylbenzenehydroperoxide, identified by GC/MS analysis, induced the formation of 8-oxo-7,8-dihydro-2 ' -deoxyguanosine and caused DNA damage at consecutive guanines, as observed with cumenehydroperoxide. Equimolar concentrations of H 2 O 2 and acetophenone were produced by the sunlight-irradiation of 1-phenylethanol, a further degraded product of ethylbenzene. These results indicate a novel pathway that oxidative DNA damage induced by the peroxide and H 2 O 2 derived from sunlight-irradiated ethylbenzene may lead to expression of the carcinogenicity

  18. Chemoprotective Effect of Taurine on Potassium Bromate-Induced DNA Damage, DNA-Protein Cross-Linking and Oxidative Stress in Rat Intestine

    Science.gov (United States)

    Ahmad, Mir Kaisar; Khan, Aijaz Ahmed; Ali, Shaikh Nisar; Mahmood, Riaz

    2015-01-01

    Potassium bromate (KBrO3) is widely used as a food additive and is a major water disinfection by-product. It induces multiple organ toxicity in humans and experimental animals and is a probable human carcinogen. The present study reports the protective effect of dietary antioxidant taurine on KBrO3-induced damage to the rat intestine. Animals were randomly divided into four groups: control, KBrO3 alone, taurine alone and taurine+ KBrO3. Administration of KBrO3 alone led to decrease in the activities of intestinal brush border membrane enzymes while those of antioxidant defence and carbohydrate metabolism were also severely altered. There was increase in DNA damage and DNA-protein cross-linking. Treatment with taurine, prior to administration of KBrO3, resulted in significant attenuation in all these parameters but the administration of taurine alone had no effect. Histological studies supported these biochemical results showing extensive intestinal damage in KBrO3-treated animals and greatly reduced tissue injury in the taurine+ KBrO3 group. These results show that taurine ameliorates bromate induced tissue toxicity and oxidative damage by improving the antioxidant defence, tissue integrity and energy metabolism. Taurine can, therefore, be potentially used as a therapeutic/protective agent against toxicity of KBrO3 and related compounds. PMID:25748174

  19. Watson-Crick Base Pair Radical Cation as a Model for Oxidative Damage in DNA.

    Science.gov (United States)

    Feketeová, Linda; Chan, Bun; Khairallah, George N; Steinmetz, Vincent; Maitre, Philippe; Radom, Leo; O'Hair, Richard A J

    2017-07-06

    The deleterious cellular effects of ionizing radiation are well-known, but the mechanisms causing DNA damage are poorly understood. The accepted molecular events involve initial oxidation and deprotonation at guanine sites, triggering hydrogen atom abstraction reactions from the sugar moieties, causing DNA strand breaks. Probing the chemistry of the initially formed radical cation has been challenging. Here, we generate, spectroscopically characterize, and examine the reactivity of the Watson-Crick nucleobase pair radical cation in the gas phase. We observe rich chemistry, including proton transfer between the bases and propagation of the radical site in deoxyguanosine from the base to the sugar, thus rupturing the sugar. This first example of a gas-phase model system providing molecular-level details on the chemistry of an ionized DNA base pair paves the way toward a more complete understanding of molecular processes induced by radiation. It also highlights the role of radical propagation in chemistry, biology, and nanotechnology.

  20. Micronutrient special issue: Coenzyme Q10 requirements for DNA damage prevention

    International Nuclear Information System (INIS)

    Schmelzer, Constance; Döring, Frank

    2012-01-01

    Coenzyme Q 10 (CoQ 10 ) is an essential component for electron transport in the mitochondrial respiratory chain and serves as cofactor in several biological processes. The reduced form of CoQ 10 (ubiquinol, Q 10 H 2 ) is an effective antioxidant in biological membranes. During the last years, particular interest has been grown on molecular effects of CoQ 10 supplementation on mechanisms related to DNA damage prevention. This review describes recent advances in our understanding about the impact of CoQ 10 on genomic stability in cells, animals and humans. With regard to several in vitro and in vivo studies, CoQ 10 provides protective effects on several markers of oxidative DNA damage and genomic stability. In comparison to the number of studies reporting preventive effects of CoQ 10 on oxidative stress biomarkers, CoQ 10 intervention studies in humans with a direct focus on markers of DNA damage are limited. Thus, more well-designed studies in healthy and disease populations with long-term follow up results are needed to substantiate the reported beneficial effects of CoQ 10 on prevention of DNA damage.

  1. Mitochondrial DNA Damage and Diseases [version 1; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    Gyanesh Singh

    2015-07-01

    Full Text Available Various endogenous and environmental factors can cause mitochondrial DNA (mtDNA damage.  One of the reasons for enhanced mtDNA damage could be its proximity to the source of oxidants, and lack of histone-like protective proteins. Moreover, mitochondria contain inadequate DNA repair pathways, and, diminished DNA repair capacity may be one of the factors responsible for high mutation frequency of the mtDNA. mtDNA damage might cause impaired mitochondrial function, and, unrepaired mtDNA damage has been frequently linked with several diseases. Exploration of mitochondrial perspective of diseases might lead to a better understanding of several diseases, and will certainly open new avenues for detection, cure, and prevention of ailments.

  2. Oxidative damage of mitochondrial and nuclear DNA induced by ionizing radiation in human hepatoblastoma cells

    International Nuclear Information System (INIS)

    Morales, Albert; Miranda, Merce; Sanchez-Reyes, Alberto; Biete, Alberto; Fernandez-Checa, Jose C.

    1998-01-01

    Purpose: Since reactive oxygen species (ROS) act as mediators of radiation-induced cellular damage, the aim of our studies was to determine the effects of ionizing radiation on the regulation of hepatocellular reduced glutathione (GSH), survival and integrity of nuclear and mitochondrial DNA (mtDNA) in human hepatoblastoma cells (Hep G2) depleted of GSH prior to radiation. Methods and Materials: GSH, oxidized glutathione (GSSG), and generation of ROS were determined in irradiated (50-500 cGy) Hep G2 cells. Clonogenic survival, nuclear DNA fragmentation, and integrity of mtDNA were assessed in cells depleted of GSH prior to radiation. Results: Radiation of Hep G2 cells (50-400 cGy) resulted in a dose-dependent generation of ROS, an effect accompanied by a decrease of reduced GSH, ranging from a 15% decrease for 50 cGy to a 25% decrease for 400 cGy and decreased GSH/GSSG from a ratio of 17 to a ratio of 7 for controls and from 16 to 6 for diethyl maleate (DEM)-treated cells. Depletion of GSH prior to radiation accentuated the increase of ROS by 40-50%. The depletion of GSH by radiation was apparent in different subcellular sites, being particularly significant in mitochondria. Furthermore, depletion of nuclear GSH to 50-60% of initial values prior to irradiation (400 cGy) resulted in DNA fragmentation and apoptosis. Consequently, the survival of Hep G2 to radiation was reduced from 25% of cells not depleted of GSH to 10% of GSH-depleted cells. Fitting the survival rate of cells as a function of GSH using a theoretical model confirmed cellular GSH as a key factor in determining intrinsic sensitivity of Hep G2 cells to radiation. mtDNA displayed an increased susceptibility to the radiation-induced loss of integrity compared to nuclear DNA, an effect that was potentiated by GSH depletion in mitochondria (10-15% intact mtDNA in GSH-depleted cells vs. 25-30% of repleted cells). Conclusion: GSH plays a critical protective role in maintaining nuclear and mtDNA functional

  3. Radioprotection against DNA damage by an extract of Indian green mussel, Perna viridis (L.)

    Digital Repository Service at National Institute of Oceanography (India)

    Kumaran, S.P.; Kutty, B.C.; Chatterji, A.; Parameswaran, P.S.; Mishra, K.P.

    -irradiation Prevention of DNA damage both in plasmid and lymphocytes and cell death in lymphocytes appears correlated with reduction of oxidatively generated free radicals It is concluded that protection against radiation-induced cell death and DNA damage by MH...

  4. Replication stress, DNA damage signalling, and cytomegalovirus infection in human medulloblastomas

    DEFF Research Database (Denmark)

    Bartek, Jiri; Fornara, Olesja; Merchut-Maya, Joanna Maria

    2017-01-01

    suppressor activation, across our medulloblastoma cohort. Most tumours showed high proliferation (Ki67 marker), variable oxidative DNA damage (8-oxoguanine lesions) and formation of 53BP1 nuclear 'bodies', the latter indicating (along with ATR-Chk1 signalling) endogenous replication stress. The bulk...... cell replication stress and DNA repair. Collectively, the scenario we report here likely fuels genomic instability and evolution of medulloblastoma resistance to standard-of-care genotoxic treatments....... eight established immunohistochemical markers to assess the status of the DDR machinery, we found pronounced endogenous DNA damage signalling (γH2AX marker) and robust constitutive activation of both the ATM-Chk2 and ATR-Chk1 DNA damage checkpoint kinase cascades, yet unexpectedly modest p53 tumour...

  5. Ultrasensitive determination of DNA oxidation products by gas chromatography-tandem mass spectrometry and the role of antioxidants in the prevention of oxidative damage.

    Science.gov (United States)

    Dawbaa, Sam; Aybastıer, Önder; Demir, Cevdet

    2017-04-15

    Oxidative stress is considered as one of the significant causes of DNA damage which in turn contributes to cell death through a series of intermediate processes such as cancer formation, mutation, and aging. Natural sources such as plant and fruit products have provided us with interesting substances of antioxidant activity that could be recruited in protecting the genetic materials of the cells. This study is an effort to discover some of those antioxidants effects in their standard and natural forms by performing an ultrasensitive determination of the products of DNA oxidation using GC-MS/MS. Experiments were used to determine the direct antioxidant activity of the substances contained in the tendrils of Vitis vinifera (var. alphonse) by extracting them and achieving Folin-Ciocalteau and CHROMAC analyses to determine the total phenolic content (TPC) and the antioxidant capacity of the extract, respectively; results revealed a phenolic content of 11.39±0.30mg Gallic Acid Equivalent (GAE)/g of the plant's fresh weight (FW) by Folin-Ciocalteau and 8.17±0.49mg Trolox Equivalent (TE)/g FW by CHROMAC assays. The qualitative analysis of the plant extract by HPLC-DAD technique revealed that two flavonoid glycosides namely rutin and isoquercitrin in addition to chlorogenic acid were contained in the extract. The determination of the DNA oxidation products was performed after putting DNA, rutin and isoquercitrin standard samples with different concentration, and the extract's sample under oxidative stress. Eighteen DNA oxidation products were traced using GC-MS/MS with ultra-sensitivity and the experiments proved a significant decrease in the concentration of the DNA oxidation products when the extract was used as a protectant against the oxidative stress. It is believed by conclusion that the extract of V. vinifera's (var. alphonse) tendrils has a good antioxidant activity; hence it is recommended to be used as a part of the daily healthy food list if possible

  6. Parkinson's disease brain mitochondria have impaired respirasome assembly, age-related increases in distribution of oxidative damage to mtDNA and no differences in heteroplasmic mtDNA mutation abundance

    Directory of Open Access Journals (Sweden)

    Keeney Paula M

    2009-09-01

    Full Text Available Abstract Background Sporadic Parkinson's disease (sPD is a nervous system-wide disease that presents with a bradykinetic movement disorder and is frequently complicated by depression and cognitive impairment. sPD likely has multiple interacting causes that include increased oxidative stress damage to mitochondrial components and reduced mitochondrial bioenergetic capacity. We analyzed mitochondria from postmortem sPD and CTL brains for evidence of oxidative damage to mitochondrial DNA (mtDNA, heteroplasmic mtDNA point mutations and levels of electron transport chain proteins. We sought to determine if sPD brains possess any mtDNA genotype-respiratory phenotype relationships. Results Treatment of sPD brain mtDNA with the mitochondrial base-excision repair enzyme 8-oxyguanosine glycosylase-1 (hOGG1 inhibited, in an age-dependent manner, qPCR amplification of overlapping ~2 kbase products; amplification of CTL brain mtDNA showed moderate sensitivity to hOGG1 not dependent on donor age. hOGG1 mRNA expression was not different between sPD and CTL brains. Heteroplasmy analysis of brain mtDNA using Surveyor nuclease® showed asymmetric distributions and levels of heteroplasmic mutations across mtDNA but no patterns that statistically distinguished sPD from CTL. sPD brain mitochondria displayed reductions of nine respirasome proteins (respiratory complexes I-V. Reduced levels of sPD brain mitochondrial complex II, III and V, but not complex I or IV proteins, correlated closely with rates of NADH-driven electron flow. mtDNA levels and PGC-1α expression did not differ between sPD and CTL brains. Conclusion PD brain mitochondria have reduced mitochondrial respiratory protein levels in complexes I-V, implying a generalized defect in respirasome assembly. These deficiencies do not appear to arise from altered point mutational burden in mtDNA or reduction of nuclear signaling for mitochondrial biogenesis, implying downstream etiologies. The origin of age

  7. No association between alcohol supplementation and autoantibodies to DNA damage in postmenopausal women in a controlled feeding study.

    Science.gov (United States)

    Mahabir, S; Baer, D J; Johnson, L L; Frenkel, K; Dorgan, J F; Cambell, W; Hartman, T J; Clevidence, B; Albanes, D; Judd, J T; Taylor, P R

    2005-08-01

    Alcohol consumption is linked to increased breast cancer risk. Since oestrogens increase breast cancer risk, possibly through oxidative damage, and we have shown that alcohol consumption increases serum oestrogens, we tested whether moderate alcohol supplementation increased oxidative DNA damage among healthy postmenopausal women not on hormone replacement therapy in a randomized controlled crossover study. We used serum 5-hydroxymethyl-2-deoxyuridine (5-HMdU) autoantibodies (aAbs) as a marker of oxidative DNA damage. The results showed no evidence for increased or decreased levels of oxidative DNA damage among women who consumed 15 g or 30 g alcohol per day for 8 weeks compared with women in the 0 g alcohol group. We conclude that among healthy women, it is possible that an 8-week trial of moderate alcohol supplementation might be too short to make enough 5-HMdU aAbs to compare differences by alcohol dose. In future studies, a panel of biomarkers for DNA damage should be used.

  8. DNA Damage Observed in Unaffected Individuals with Family History of T2DM

    Science.gov (United States)

    Ramesh, Nikhila; Abilash, V. G.

    2017-11-01

    Diabetes has been documented to cause high levels of DNA fragmentation in some cases. As diabetes is inheritable and influenced by both genetic and environmental factors, an investigation into the genomic stability of individuals who are strongly at risk of inheriting diabetes was conducted by inducing oxidative stress, as DNA damage in unaffected individuals could be a sign of onset of the disease or the presence of genetic alterations that reduce cellular defences against reactive oxygen species. In this study, alkaline comet assay was performed on isolated human leukocytes to determine whether individuals with a family history of Type 2 Diabetes Mellitus (T2DM) are more prone to DNA damage under oxidative stress. Visual scoring of comets showed that these individuals have higher degree of DNA damage compared to a control individual with no family history of Type 2 Diabetes Mellitus. Further studies with large sample could determine the presence of disabled cellular defences against oxidative stress in unaffected individuals and intervention with antioxidants could prevent or manage Type 2 Diabetes Mellitus and its complications.

  9. Analysis of oxidative DNA damage, Part II: Synthesis of the internal standard 8-[18O]hydroxy-2'-deoxyguanosine

    NARCIS (Netherlands)

    Hermanns RCA; Zomer G; Stavenuiter JFC; Westra G; Visser T; van de Werken G

    1993-01-01

    In the project 'Oxidative DNA Damage' the first aim is to develop a mass spectrometric method for the quantification of 8-hydroxy-2'- deoxyguanosine (oh8dG). The required precision of the method requires the application of a labeled analogue as an internal standard. This report

  10. Eccentric localization of catalase to protect chromosomes from oxidative damages during meiotic maturation in mouse oocytes.

    Science.gov (United States)

    Park, Yong Seok; You, Seung Yeop; Cho, Sungrae; Jeon, Hyuk-Joon; Lee, Sukchan; Cho, Dong-Hyung; Kim, Jae-Sung; Oh, Jeong Su

    2016-09-01

    The maintenance of genomic integrity and stability is essential for the survival of every organism. Unfortunately, DNA is vulnerable to attack by a variety of damaging agents. Oxidative stress is a major cause of DNA damage because reactive oxygen species (ROS) are produced as by-products of normal cellular metabolism. Cells have developed eloquent antioxidant defense systems to protect themselves from oxidative damage along with aerobic metabolism. Here, we show that catalase (CAT) is present in mouse oocytes to protect the genome from oxidative damage during meiotic maturation. CAT was expressed in the nucleus to form unique vesicular structures. However, after nuclear envelope breakdown, CAT was redistributed in the cytoplasm with particular focus at the chromosomes. Inhibition of CAT activity increased endogenous ROS levels, but did not perturb meiotic maturation. In addition, CAT inhibition produced chromosomal defects, including chromosome misalignment and DNA damage. Therefore, our data suggest that CAT is required not only to scavenge ROS, but also to protect DNA from oxidative damage during meiotic maturation in mouse oocytes.

  11. [Association of cooking oil fumes exposure and oxidative DNA damage among occupational exposed populations].

    Science.gov (United States)

    Ke, Yue-bin; Xu, Xin-yun; Yuan, Jian-hui; Fang, Shi-song; Liu, Yi-min; Wu, Tang-chun

    2010-08-01

    Previous investigations indicate that cooks are exposed to polycyclic aromatic hydrocarbons (PAH) from cooking oil fumes (COF). However, Emission of PAH and their carcinogenic potencies from cooking oil fumes sources have not been investigated among cooks. To investigate the urinary excretion of a marker for oxidative DNA damage, 8-hydroxydeoxyguanosine (8-OHdG), in different groups of cooks and different exposure groups, and to study the association between 8-OHdG and 1-hydroxypyrene (1-OHP), a biological marker for PAH exposure. Urine samples were collected from different groups of cooks (n = 86) and from unexposed controls (n = 36), all are male with similar age and smoking habits. The health status, occupational history, smoking, and alcohol consumption 24 hours prior to sampling was estimated from questionnaires. The urinary samples were frozen for later analyses of 8-OHdG and 1-OHP by high performance liquid chromatography. Excretion in urine of 8-OHdG were similar for controls (mean 1.2 µmol/mol creatinine, n = 36), and for those who had been in the kitchen room with exhaust hood operation (mean 1.5 µmol/mol creatinine, n = 45). COF exposed cooks without exhaust hood operation had increased excretion of 8-OHdG (mean 2.3 µmol/mol creatinine, n = 18). The difference between this group and the unexposed controls was significant. The urinary levels of ln 1-OHP and ln 8-OHdG were still significantly correlated in a multiple regression analysis. Results indicate that exposure to PAH or possibly other compounds in COF may cause oxidative DNA damage.

  12. Increased levels of oxidative DNA damage attributable to cooking-oil fumes exposure among cooks.

    Science.gov (United States)

    Ke, Yuebin; Cheng, Jinquan; Zhang, Zhicheng; Zhang, Renli; Zhang, Zhunzhen; Shuai, Zhihong; Wu, Tangchun

    2009-07-01

    Previous investigations have indicated that cooks are exposed to polycyclic aromatic hydrocarbons (PAHs) from cooking-oil fumes. However, Emission of PAH and their carcinogenic potencies from cooking oil fumes sources have not been investigated among cooks. To investigate the urinary excretion of a marker for oxidative DNA damage, 8-hydroxydeoxyguanosine (8-OHdG), in different groups of cooks and different exposure groups, and to study the association between 8-OHdG and 1-hydroxypyrene(1-OHP), a biological marker for PAH exposure. Urine samples were collected from different groups of cooks (n = 86) and from unexposed controls (n = 36); all were male with similar age and smoking habits. The health status, occupational history, smoking, and alcohol consumption 24 h prior to sampling was estimated from questionnaires. The urine samples were frozen for later analyses of 8-OHdG and 1-OHP levels by high-performance liquid chromatography. Excretion in urine of 8-OHdG was similar for controls (mean 1.2micromol/mol creatinine, n = 36), and for those who had been in the kitchen with an exhaust-hood operating (mean 1.5micromol/mol creatinine, n = 45). Cooks exposed to cooking-oil fumes without exhaust-hood operation had significantly increased excretion of 8-OHdG (mean 2.3micromol/mol creatinine, n = 18), compared with controls. The urinary levels of ln 1-OHP and ln 8-OHdG were still significantly correlated in a multiple regression analysis. The results indicate that exposure to PAH or possibly other compounds in cooking-oil fumes may cause oxidative DNA damage.

  13. DNA Damage, Fruits and Vegetables and Breast Cancer Prevention

    National Research Council Canada - National Science Library

    Thompson, Henry

    2002-01-01

    The purpose of this project is to evaluate the effect(s) of increasing fruit and vegetable intake on oxidative DNA damage and lipid peroxidation in a population of women at elevated risk for breast cancer...

  14. DNA Damage, Fruits and Vegetables and Breast Cancer Prevention

    National Research Council Canada - National Science Library

    Thompson, Henry

    2001-01-01

    The purpose of this project is to evaluate the effect(s) of increasing fruit and vegetable intake on oxidative DNA damage and lipid peroxidation in a population of women at elevated risk for breast cancer...

  15. DNA Damage, Fruits and Vegetables and Breast Cancer Prevention

    National Research Council Canada - National Science Library

    Thompson, Henry

    2003-01-01

    The purpose of this project was to evaluate the effect(s) of increasing fruit and vegetable intake on oxidative DNA damage and lipid peroxidation in a population of women at elevated risk for breast cancer...

  16. DNA Damage, Fruits and Vegetables and Breast Cancer Prevention

    National Research Council Canada - National Science Library

    Thompson, Henry

    2000-01-01

    The purpose of this project is to evaluate the effect(s) of increasing fruit and vegetable intake on oxidative DNA damage and lipid peroxidation in a population of women at elevated risk for breast cancer...

  17. UV and ionizing radiations induced DNA damage, differences and similarities

    Science.gov (United States)

    Ravanat, Jean-Luc; Douki, Thierry

    2016-11-01

    Both UV and ionizing radiations damage DNA. Two main mechanisms, so-called direct and indirect pathways, are involved in the degradation of DNA induced by ionizing radiations. The direct effect of radiation corresponds to direct ionization of DNA (one electron ejection) whereas indirect effects are produced by reactive oxygen species generated through water radiolysis, including the highly reactive hydroxyl radicals, which damage DNA. UV (and visible) light damages DNA by again two distinct mechanisms. UVC and to a lesser extend UVB photons are directly absorbed by DNA bases, generating their excited states that are at the origin of the formation of pyrimidine dimers. UVA (and visible) light by interaction with endogenous or exogenous photosensitizers induce the formation of DNA damage through photosensitization reactions. The excited photosensitizer is able to induce either a one-electron oxidation of DNA (type I) or to produce singlet oxygen (type II) that reacts with DNA. In addition, through an energy transfer from the excited photosensitizer to DNA bases (sometime called type III mechanism) formation of pyrimidine dimers could be produced. Interestingly it has been shown recently that pyrimidine dimers are also produced by direct absorption of UVA light by DNA, even if absorption of DNA bases at these wavelengths is very low. It should be stressed that some excited photosensitizers (such as psoralens) could add directly to DNA bases to generate adducts. The review will described the differences and similarities in terms of damage formation (structure and mechanisms) between these two physical genotoxic agents.

  18. The current state of eukaryotic DNA base damage and repair.

    Science.gov (United States)

    Bauer, Nicholas C; Corbett, Anita H; Doetsch, Paul W

    2015-12-02

    DNA damage is a natural hazard of life. The most common DNA lesions are base, sugar, and single-strand break damage resulting from oxidation, alkylation, deamination, and spontaneous hydrolysis. If left unrepaired, such lesions can become fixed in the genome as permanent mutations. Thus, evolution has led to the creation of several highly conserved, partially redundant pathways to repair or mitigate the effects of DNA base damage. The biochemical mechanisms of these pathways have been well characterized and the impact of this work was recently highlighted by the selection of Tomas Lindahl, Aziz Sancar and Paul Modrich as the recipients of the 2015 Nobel Prize in Chemistry for their seminal work in defining DNA repair pathways. However, how these repair pathways are regulated and interconnected is still being elucidated. This review focuses on the classical base excision repair and strand incision pathways in eukaryotes, considering both Saccharomyces cerevisiae and humans, and extends to some important questions and challenges facing the field of DNA base damage repair. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  19. Hyperactivation of Akt/mTOR and deficiency in tuberin increased the oxidative DNA damage in kidney cancer patients with diabetes.

    Science.gov (United States)

    Habib, Samy L; Liang, Sitai

    2014-05-15

    Recent study from our laboratory showed that patients with diabetes are at a higher risk of developing kidney cancer. In the current study, we have explored one of the mechanisms by which diabetes accelerates tumorigenesis in the kidney. Kidney cancer tissue from patients with diabetes showed a higher activity of Akt and decreased in total protein of tuberin compared to kidney cancer patient without diabetes or diabetes alone. In addition, a significant increase in phospho-Akt/tuberin expression was associated with an increase in Ki67 expression and activation of mTOR in kidney tumor with or without diabetes compared to diabetes alone. In addition, decrease in tuberin expression resulted in a significant decrease in protein expression of OGG1 and increased in oxidative DNA damage, 8-oxodG in kidney tissues from patients with cancer or cancer+diabetes. Importantly, these data showed that the majority of the staining of Akt/tuberin/p70S6K phosphorylation was more prominently in the tubular cells. In addition, accumulation of oxidative DNA damage is localized only in the nucleus of tubular cells within the cortex region. These data suggest that Akt/tuberin/mTOR pathway plays an important role in the regulation DNA damage and repair pathways that may predispose diabetic kidneys to pathogenesis of renal cell carcinoma.

  20. Genetic damage caused by methyl-parathion in mouse spermatozoa is related to oxidative stress

    International Nuclear Information System (INIS)

    Pina-Guzman, B.; Solis-Heredia, M.J.; Rojas-Garcia, A.E.; Uriostegui-Acosta, M.; Quintanilla-Vega, B.

    2006-01-01

    Organophosphorous (OP) pesticides are considered genotoxic mainly to somatic cells, but results are not conclusive. Few studies have reported OP alterations on sperm chromatin and DNA, and oxidative stress has been related to their toxicity. Sperm cells are very sensitive to oxidative damage which has been associated with reproductive dysfunctions. We evaluated the effects of methyl-parathion (Me-Pa; a widely used OP) on sperm DNA, exploring the sensitive stage(s) of spermatogenesis and the relationship with oxidative stress. Male mice (10-12-weeks old) were administered Me-Pa (3-20 mg/kg bw/i.p.) and euthanized at 7- or 28-days post-treatment. Mature spermatozoa were obtained and evaluated for chromatin structure through SCSA (Sperm Chromatin Structure Assay; DNA Fragmentation Index parameters: Mean DFI and DFI%) and chromomycin-A 3 (CMA 3 )-staining, for DNA damage through in situ-nick translation (NT-positive) and for oxidative stress through lipid peroxidation (LPO; malondialdehyde production). At 7-days post-treatment (mature spermatozoa when Me-Pa exposure), dose-dependent alterations in chromatin structure (Mean DFI and CMA 3 -staining) were observed, as well as increased DNA damage, from 2-5-fold in DFI% and NT-positive cells. Chromatin alterations and DNA damage were also observed at 28-days post-treatment (cells at meiosis at the time of exposure); suggesting that the damage induced in spermatocytes was not repaired. Positive correlations were observed between LPO and sperm DNA-related parameters. These data suggest that oxidative stress is related to Me-Pa alterations on sperm DNA integrity and cells at meiosis (28-days post-treatment) and epididymal maturation (7-days post-treatment) are Me-Pa targets. These findings suggest a potential risk of Me-Pa to the offspring after transmission

  1. Repair of endogenous and ionizing radiation-induced DNA damages: mechanisms and biological functions

    International Nuclear Information System (INIS)

    Boiteux, S.

    2002-01-01

    The cellular DNA is continuously exposed to endogenous and exogenous stress. Oxidative stress due to cellular metabolism is the major cause of endogenous DNA damage. On the other hand, ionizing radiation (IR) is an important exogenous stress. Both induce similar DNA damages: damaged bases, abasic sites and strand breakage. Most of these lesions are lethal and/or mutagenic. The survival of the cell is managed by efficient and accurate DNA repair mechanisms that remove lesions before their replication or transcription. DNA repair pathways involved in the removal of IR-induced lesions are briefly described. Base excision repair (BER) is mostly involved in the removal of base damage, abasic sites and single strand breaks. In contrast, DNA double strand breaks are mostly repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). How DNA repair pathways prevent cancer process is also discussed. (author)

  2. Micronutrient special issue: Coenzyme Q{sub 10} requirements for DNA damage prevention

    Energy Technology Data Exchange (ETDEWEB)

    Schmelzer, Constance, E-mail: schmelzer@fbn-dummerstorf.de [Leibniz Institute for Farm Animal Biology (FBN), Nutritional Physiology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf (Germany); Doering, Frank [University of Kiel, Institute of Human Nutrition and Food Science, Molecular Prevention, Heinrich-Hecht-Platz 10, 24118 Kiel (Germany)

    2012-05-01

    Coenzyme Q{sub 10} (CoQ{sub 10}) is an essential component for electron transport in the mitochondrial respiratory chain and serves as cofactor in several biological processes. The reduced form of CoQ{sub 10} (ubiquinol, Q{sub 10}H{sub 2}) is an effective antioxidant in biological membranes. During the last years, particular interest has been grown on molecular effects of CoQ{sub 10} supplementation on mechanisms related to DNA damage prevention. This review describes recent advances in our understanding about the impact of CoQ{sub 10} on genomic stability in cells, animals and humans. With regard to several in vitro and in vivo studies, CoQ{sub 10} provides protective effects on several markers of oxidative DNA damage and genomic stability. In comparison to the number of studies reporting preventive effects of CoQ{sub 10} on oxidative stress biomarkers, CoQ{sub 10} intervention studies in humans with a direct focus on markers of DNA damage are limited. Thus, more well-designed studies in healthy and disease populations with long-term follow up results are needed to substantiate the reported beneficial effects of CoQ{sub 10} on prevention of DNA damage.

  3. Phorate-induced oxidative stress, DNA damage and transcriptional activation of p53 and caspase genes in male Wistar rats

    Energy Technology Data Exchange (ETDEWEB)

    Saquib, Quaiser [Department of Zoology, College of Science, King Saud University, Riyadh (Saudi Arabia); Attia, Sabry M. [Department of Pharmacology, College of Pharmacy, King Saud University, Riyadh (Saudi Arabia); Siddiqui, Maqsood A. [Department of Zoology, College of Science, King Saud University, Riyadh (Saudi Arabia); Aboul-Soud, Mourad A.M. [Department of Zoology, College of Science, King Saud University, Riyadh (Saudi Arabia); Biochemistry Department, Faculty of Agriculture, Cairo University, 12613 Giza (Egypt); Al-Khedhairy, Abdulaziz A. [Department of Zoology, College of Science, King Saud University, Riyadh (Saudi Arabia); Giesy, John P. [Department of Zoology, College of Science, King Saud University, Riyadh (Saudi Arabia); Department of Biomedical and Veterinary Biosciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Canada S7N 5B3 (Canada); Zoology Department and Center for Integrative Toxicology, Michigan State University, East Lansing 48824 (United States); Musarrat, Javed, E-mail: musarratj1@yahoo.com [Department of Zoology, College of Science, King Saud University, Riyadh (Saudi Arabia); Department of Microbiology, Faculty of Agricultural Sciences, AMU, Aligarh (India)

    2012-02-15

    Male Wistar rats exposed to a systemic organophosphorus insecticide, phorate [O,O-diethyl S-[(ethylthio) methyl] phosphorothioate] at varying oral doses of 0.046, 0.092 or 0.184 mg phorate/kg bw for 14 days, exhibited substantial oxidative stress, cellular DNA damage and activation of apoptosis-related p53, caspase 3 and 9 genes. The histopathological changes including the pyknotic nuclei, inflammatory leukocyte infiltrations, renal necrosis, and cardiac myofiber degeneration were observed in the liver, kidney and heart tissues. Biochemical analysis of catalase and glutathione revealed significantly lesser activities of antioxidative enzymes and lipid peroxidation in tissues of phorate exposed rats. Furthermore, generation of intracellular reactive oxygen species and reduced mitochondrial membrane potential in bone marrow cells confirmed phorate-induced oxidative stress. Significant DNA damage was measured through comet assay in terms of the Olive tail moment in bone marrow cells of treated animals as compared to control. Cell cycle analysis also demonstrated the G{sub 2}/M arrest and appearance of a distinctive SubG{sub 1} peak, which signified induction of apoptosis. Up-regulation of tumor suppressor p53 and caspase 3 and 9 genes, determined by quantitative real-time PCR and enzyme-linked immunosorbent assay, elucidated the activation of intrinsic apoptotic pathways in response to cellular stress. Overall, the results suggest that phorate induces genetic alterations and cellular toxicity, which can adversely affect the normal cellular functioning in rats. -- Highlights: ► This is the first report on molecular toxicity of phorate in an in vivo test system. ► Phorate induces biochemical and histological changes in liver, kidney and heart. ► Rats treated with phorate exhibited DNA damage in bone marrow cells. ► Phorate induces apoptosis, oxidative stress and alters mitochondrial fluorescence. ► Phorate induces transcriptional changes and enhanced

  4. Phorate-induced oxidative stress, DNA damage and transcriptional activation of p53 and caspase genes in male Wistar rats

    International Nuclear Information System (INIS)

    Saquib, Quaiser; Attia, Sabry M.; Siddiqui, Maqsood A.; Aboul-Soud, Mourad A.M.; Al-Khedhairy, Abdulaziz A.; Giesy, John P.; Musarrat, Javed

    2012-01-01

    Male Wistar rats exposed to a systemic organophosphorus insecticide, phorate [O,O-diethyl S-[(ethylthio) methyl] phosphorothioate] at varying oral doses of 0.046, 0.092 or 0.184 mg phorate/kg bw for 14 days, exhibited substantial oxidative stress, cellular DNA damage and activation of apoptosis-related p53, caspase 3 and 9 genes. The histopathological changes including the pyknotic nuclei, inflammatory leukocyte infiltrations, renal necrosis, and cardiac myofiber degeneration were observed in the liver, kidney and heart tissues. Biochemical analysis of catalase and glutathione revealed significantly lesser activities of antioxidative enzymes and lipid peroxidation in tissues of phorate exposed rats. Furthermore, generation of intracellular reactive oxygen species and reduced mitochondrial membrane potential in bone marrow cells confirmed phorate-induced oxidative stress. Significant DNA damage was measured through comet assay in terms of the Olive tail moment in bone marrow cells of treated animals as compared to control. Cell cycle analysis also demonstrated the G 2 /M arrest and appearance of a distinctive SubG 1 peak, which signified induction of apoptosis. Up-regulation of tumor suppressor p53 and caspase 3 and 9 genes, determined by quantitative real-time PCR and enzyme-linked immunosorbent assay, elucidated the activation of intrinsic apoptotic pathways in response to cellular stress. Overall, the results suggest that phorate induces genetic alterations and cellular toxicity, which can adversely affect the normal cellular functioning in rats. -- Highlights: ► This is the first report on molecular toxicity of phorate in an in vivo test system. ► Phorate induces biochemical and histological changes in liver, kidney and heart. ► Rats treated with phorate exhibited DNA damage in bone marrow cells. ► Phorate induces apoptosis, oxidative stress and alters mitochondrial fluorescence. ► Phorate induces transcriptional changes and enhanced activities of

  5. A chronic increase of corticosterone age-dependently reduces systemic DNA damage from oxidation in rats

    DEFF Research Database (Denmark)

    Jorgensen, Anders; Kalliokoski, Otto; Forsberg, Kristin

    2017-01-01

    Stress and depression are associated with an acceleration of brain and bodily aging; effects which have been attributed to chronic elevations of glucocorticoids. We tested the hypothesis that a three week administration of stress-associated levels of corticosterone (CORT, the principal rodent...... glucocorticoid) would increase systemic and CNS DNA and RNA damage from oxidation; a phenomenon known to be centrally involved in the aging process. We also hypothesized that older individuals would be more sensitive to this effect and that the chronic CORT administration would exacerbate age-related memory...

  6. Oxidative Stress Induced Lipid Peroxidation And DNA Adduct Formation In The Pathogenesis Of Multiple Myeloma And Lymphoma

    Directory of Open Access Journals (Sweden)

    Tandon, Ravi

    2013-02-01

    Full Text Available Objective: To access the oxidative stress status by quantification of byproducts generated during lipid peroxidation and DNA breakdown products generated during DNA damage in the blood serum of multiple myeloma and lymphoma patients.Material & Methods: Case control study comprised of 40 patients of multiple myeloma and 20 patients of lymphoma along with 20 age and sex-matched healthy subjects as controls. Levels of Malondialdehyde and 8-hydroxy-2-deoxy-Guanosine were measured to study the oxidative stress status in the study subjects.Results: The level of markers of DNA damage and lipid peroxidation were found to be raised significantly in the study subjects in comparison to healthy controls. The results indicate oxidative stress and DNA damage activity increase progressively with the progression of disease.Conclusion: Oxidative stress causes DNA damage and Lipid peroxidation which results in the formation of DNA adducts leading to mutations thereby indicate the role of oxidative stress in the pathogenesis of multiple myeloma and lymphoma.

  7. Sinularin Selectively Kills Breast Cancer Cells Showing G2/M Arrest, Apoptosis, and Oxidative DNA Damage

    Directory of Open Access Journals (Sweden)

    Hurng-Wern Huang

    2018-04-01

    Full Text Available The natural compound sinularin, isolated from marine soft corals, is antiproliferative against several cancers, but its possible selective killing effect has rarely been investigated. This study investigates the selective killing potential and mechanisms of sinularin-treated breast cancer cells. In 3-(4,5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H- tetrazolium, inner salt (MTS assay, sinularin dose-responsively decreased the cell viability of two breast cancer (SKBR3 and MDA-MB-231 cells, but showed less effect on breast normal (M10 cells after a 24 h treatment. According to 7-aminoactinomycin D (7AAD flow cytometry, sinularin dose-responsively induced the G2/M cycle arrest of SKBR3 cells. Sinularin dose-responsively induced apoptosis on SKBR3 cells in terms of a flow cytometry-based annexin V/7AAD assay and pancaspase activity, as well as Western blotting for cleaved forms of poly(ADP-ribose polymerase (PARP, caspases 3, 8, and 9. These caspases and PARP activations were suppressed by N-acetylcysteine (NAC pretreatment. Moreover, sinularin dose-responsively induced oxidative stress and DNA damage according to flow cytometry analyses of reactive oxygen species (ROS, mitochondrial membrane potential (MitoMP, mitochondrial superoxide, and 8-oxo-2′-deoxyguanosine (8-oxodG. In conclusion, sinularin induces selective killing, G2/M arrest, apoptosis, and oxidative DNA damage of breast cancer cells.

  8. Voltammetric Detection of Damage to DNA by Arsenic Compounds at a DNA Biosensor

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    R. Wennrich

    2005-11-01

    Full Text Available DNA biosensor can serve as a powerfull tool for simple in vitro tests of chemicaltoxicity. In this paper, damage to DNA attached to the surface of screen-printed carbonelectrode by arsenic compounds in solution is described. Using the Co(III complex with1,10-phenanthroline, [Co(phen3]3+ , as an electrochemical DNA marker and the Ru(IIcomplex with bipyridyne, [Ru(bipy3]2+ , as a DNA oxidation catalyst, the portion of originaldsDNA which survives an incubation of the biosensor in the cleavage medium was evaluated.The model cleavage mixture was composed of an arsenic compound at 10-3 mol/Lconcentration corresponding to real contaminated water, 2x10-4 mol/L Fe(II or Cu(II ions asthe redox catalyst, and 1.5x10-2 mol/L hydrogen peroxide. DNA damage by arsenite,dimethylarsinic acid as the metabolic product of inorganic arsenic and widely used herbicide,as well as phenylarsonic acid and p-arsanilic acid as the representatives of feed additives wasfound in difference to arsenate.

  9. Vorinostat induces reactive oxygen species and DNA damage in acute myeloid leukemia cells.

    Directory of Open Access Journals (Sweden)

    Luca A Petruccelli

    Full Text Available Histone deacetylase inhibitors (HDACi are promising anti-cancer agents, however, their mechanisms of action remain unclear. In acute myeloid leukemia (AML cells, HDACi have been reported to arrest growth and induce apoptosis. In this study, we elucidate details of the DNA damage induced by the HDACi vorinostat in AML cells. At clinically relevant concentrations, vorinostat induces double-strand breaks and oxidative DNA damage in AML cell lines. Additionally, AML patient blasts treated with vorinostat display increased DNA damage, followed by an increase in caspase-3/7 activity and a reduction in cell viability. Vorinostat-induced DNA damage is followed by a G2-M arrest and eventually apoptosis. We found that pre-treatment with the antioxidant N-acetyl cysteine (NAC reduces vorinostat-induced DNA double strand breaks, G2-M arrest and apoptosis. These data implicate DNA damage as an important mechanism in vorinostat-induced growth arrest and apoptosis in both AML cell lines and patient-derived blasts. This supports the continued study and development of vorinostat in AMLs that may be sensitive to DNA-damaging agents and as a combination therapy with ionizing radiation and/or other DNA damaging agents.

  10. Vorinostat Induces Reactive Oxygen Species and DNA Damage in Acute Myeloid Leukemia Cells

    Science.gov (United States)

    Pettersson, Filippa; Retrouvey, Hélène; Skoulikas, Sophia; Miller, Wilson H.

    2011-01-01

    Histone deacetylase inhibitors (HDACi) are promising anti-cancer agents, however, their mechanisms of action remain unclear. In acute myeloid leukemia (AML) cells, HDACi have been reported to arrest growth and induce apoptosis. In this study, we elucidate details of the DNA damage induced by the HDACi vorinostat in AML cells. At clinically relevant concentrations, vorinostat induces double-strand breaks and oxidative DNA damage in AML cell lines. Additionally, AML patient blasts treated with vorinostat display increased DNA damage, followed by an increase in caspase-3/7 activity and a reduction in cell viability. Vorinostat-induced DNA damage is followed by a G2-M arrest and eventually apoptosis. We found that pre-treatment with the antioxidant N-acetyl cysteine (NAC) reduces vorinostat-induced DNA double strand breaks, G2-M arrest and apoptosis. These data implicate DNA damage as an important mechanism in vorinostat-induced growth arrest and apoptosis in both AML cell lines and patient-derived blasts. This supports the continued study and development of vorinostat in AMLs that may be sensitive to DNA-damaging agents and as a combination therapy with ionizing radiation and/or other DNA damaging agents. PMID:21695163

  11. DNA damage and radical reactions: Mechanistic aspects, formation in cells and repair studies

    International Nuclear Information System (INIS)

    Cadet, J.; Ravanat, J.L.; Carell, T.; Cellai, L.; Chatgilialoglu, Ch.; Gimisis, Th.; Miranda, M.; O'Neill, P.; Robert, M.

    2008-01-01

    Several examples of oxidative and reductive reactions of DNA components that lead to single and tandem modifications are discussed in this review. These include nucleophilic addition reactions of the one-electron oxidation-mediated guanine radical cation and the one-electron reduced intermediate of 8-bromo-purine 2'-de-oxy-ribo-nucleosides that give rise to either an oxidizing guanine radical or related 5',8-cyclo-purine nucleosides. In addition, mechanistic insights into the reductive pathways involved in the photolyase induced reversal of cyclo-buta-cli-pyrimidine and pyrimidine (6-4) pyrimidone photoproducts are provided. Evidence for the occurrence and validation in cellular DNA of (OH) · radical degradation pathways of guanine that have been established in model systems has been gained from the accurate measurement of degradation products. Relevant information on biochemical aspects of the repair of single and clustered oxidatively generated damage to DNA has been gained from detailed investigations that rely on the synthesis of suitable modified probes. Thus the preparation of stable carbocyclic derivatives of purine nucleoside containing defined sequence oligonucleotides has allowed detailed crystallographic studies of the recognition step of the base damage by enzymes implicated in the base excision repair (BER) pathway. Detailed insights are provided on the BER processing of non-double strand break bi-stranded clustered damage that may consist of base lesions, a single strand break or abasic sites and represent one of the main deleterious classes of radiation-induced DNA damage. (authors)

  12. An investigation of the effects of Cinnamomum cassia bark extracts on oxidative DNA damage and possible cytotoxic and apoptotic activities in transformed/untransformed cell lines from Type 1 diabetic patients, in vitro.

    Directory of Open Access Journals (Sweden)

    Ferzan Lermioglu Erciyas

    2015-05-01

    Full Text Available It was shown that patients with Type 1 diabetes mellitus (T1DM had increased level of oxidative DNA damage and decreased efficacy of DNA repair. These changes were implicated in the increased cancer risk in patients with diabetes mellitus. Cinnamon bark extracts have diverse biological activities including antidiabetic and anti-tumor properties. Cinnamomum cassia (C. cassia is a common used cinnamon species present in commercial cinnamon preparations. We aimed to investigate the effects of cinnamon extracts prepared from C. cassia bark on endogenous and hydrogen peroxide (H2O2-induced oxidative DNA damage, as well as cytotoxic and apoptotic activities in this study. Type 1 diabetic (T1DM lymphocytes (GM02765, GM01838 and fibroblasts (GM01837 were obtained from NIGMS Human Genetic Cell Repository of Coriell Institute, New Jersey, USA. Cytotoxicity analysis were performed by using a tetrazolium salt, 4-[3-(4-iodophenyl 2-(4-nitrophenyl 2H-5-tetrazolio] 1,3-benzene disulfonate (WST-1. The effects of extracts on endogenous and H2O2-induced oxidative DNA damage were studied using the single cell gel electrophoresis (SCGE; Comet Assay, a technique allowing DNA damage in a single cell. Apoptotic activities of extracts were investigated by TUNEL and Annexin V/PI assays. using flow cytometry. IC50 and IC20 values of the extracts varied and the effects on endogenous and H2O2-induced DNA damage were different regarding cell lines and extracts. Although their protective effects at some doses against to H2O2-induced oxidative damage, our results suggested DNA damaging and apoptotic potential of cinnamon bark extracts on Type 1 diabetic cell lines, in vitro.

  13. Genomics and radical mediated DNA damage: major differences between ionizing radiation and DNA-cleaving enediynes

    International Nuclear Information System (INIS)

    Cosgrove, J.P.; Begley, T.J.; Samson, L.D.; Dedon, P.C.

    2003-01-01

    While the evidence is strong for radical-mediated oxidative processes in the pathophysiology of cancer and aging, the mechanisms by which cells respond to oxidative stress have eluded definition. To this end, we have undertaken genomic studies comparing the response of S. cerevisiae to DNA-specific oxidizing agents, the enediynes calicheamicin (CAL), esperamicin (ESP), and neocarzinostatin (NCS), and the non-specific gamma-radiation (RAD). While RAD results in relatively indiscriminate oxidation of cellular molecules, the enediynes are highly specific to DNA and produce damage by a common mechanism involving radical-mediated oxidation of deoxyribose. Transcriptional profiling in response to these agents (80% survival; 15 min exposure; Affymetrix) revealed unexpected differences between RAD and the enediynes and among the three enediynes. Only 2 genes responded in common to all agents, while 9 genes were regulated in common for the 3 enediynes (no DNA repair genes altered in common). The limited common gene expression changes for the 3 enediynes may result from differences in deoxyribose oxidation chemistry, DNA and chromatin targets or the proportions of single- and double-strand DNA lesions. RAD produced a more robust response than the enediynes, altering expression of 195 and 52 genes by more than 2- and 5-fold, respectively, compared to 16-44 and *2 genes, respectively, for the enediynes. This suggests that the transcriptional response varies in intensity according to the number of cellular features affected by the toxin. Genes showing the strongest up-regulation with RAD: ribonucleotide reductase, multidrug resistance, DS break repair/RAD51, GSH transferase; strongly reduced gene expression: TEL1 (damage signaling), NAT2 (acetyltransferase). Genomic phenotyping studies, using a subset of the Research Genetics deletion library, revealed that loss of apn1, the major AP endonuclease, caused resistance to NCS, possibly due to reduced formation of protein-DNA cross

  14. Umbelliferone arrest cell cycle at G0/G1 phase and induces apoptosis in human oral carcinoma (KB) cells possibly via oxidative DNA damage.

    Science.gov (United States)

    Vijayalakshmi, Annamalai; Sindhu, Ganapathy

    2017-08-01

    Umbelliferone (UMB) has widespread pharmacological activity, comprising anti-inflammatory, anti-oxidant, anti-genotoxic and anti-immunomodulatory but the anticancer activity remains unknown in human oral carcinoma (HOC) KB cells. MTT assay determinations was revealed that treatment of KB cells with UMB, prevent and reduce the cell proliferation with the IC 50 - 200μM as well as induces loss of cell viability, morphology change and internucleosomal DNA fragmentation in a concentration dependent manner. Acridine orange and ethidium bromide dual staining assay established that UMB induced apoptosis in KB cells in a dose dependent manner. Alkaline comet assay determination revealed UMB has the potential to increase oxidative DNA damage in KB cells through DNA tail formation significantly (pKB cells. Similarly, we observed increased DNA damage stimulated apoptotic morphological changes in UMB treated cells. Taken together, the present study suggests that UMB exhibits anticancer effect on KB cell line with the increased generation of intracellular ROS, triggered oxidative stress mediated depolarization of mitochondria, which contributes cell death via DNA damage as well as cell cycle arrest at G0/G1 phase. The results have also provided us insight in the pharmacological backgrounds for the potential use of UMB, to target divergent pathways of cell survival and cell death. To conclude UMB could develop as a novel candidate for cancer chemoprevention and therapy, which is our future focus and to develop a connectivity map between in vivo and in vitro activity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. The effects of lycopene on DNA damage and oxidative stress on indomethacin-induced gastric ulcer in rats.

    Science.gov (United States)

    Boyacioglu, Murat; Kum, Cavit; Sekkin, Selim; Yalinkilinc, Hande Sultan; Avci, Hamdi; Epikmen, Erkmen Tugrul; Karademir, Umit

    2016-04-01

    Lycopene, the main antioxidant compound present in tomatoes, has high singlet oxygen- and peroxyl radicals-quenching ability, resulting in protection against oxidative damage in aerobic cell. Indomethacin is a nonsteroidal anti-inflammatory drug, and can promote oxidative damage in gastric tissue. The aim of this study was to investigate the protective effects of lycopene on an indomethacin-induced gastric ulcer model. A total of 42 adult male Wistar rats were divided into six groups of seven animals as follows: control, indomethacin, lansoprazole, lycopene 10 mg/kg, lycopene 50 mg/kg and lycopene 100 mg/kg. Gastric ulcers were induced by oral administration of indomethacin, after which the differing doses of lycopene were administered by oral gavage. The efficacy of lycopene was compared with lansoprazole. DNA damage of lymphocytes was measured by comet assay. Activities of superoxide dismutase, catalase and myeloperoxidase, as well as malondialdehyde and glutathione levels were determined in stomach tissue. This tissue was also taken for pathological investigations. The TUNEL method was used to detect apoptotic cells in paraffin sections. The results showed that 100 mg/kg lycopene administration significantly decreased % Tail DNA and Mean Tail Moment in the gastric ulcer group, compared with the other treatment groups. This same dose of lycopene also significantly decreased high malondialdehyde level and myeloperoxidase activity, and increased the activity of antioxidant enzymes (with the exception of catalase) in tissue. Apoptosis rates in the stomachs of the rats correlated with the biochemical and histopathological findings. These results indicated that lycopene might have a protective effect against indomethacin-induced gastric ulcer and oxidative stress in rats. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  16. In vitro Repair of Oxidative DNA Damage by Human Nucleotide Excision Repair System: Possible Explanation for Neurodegeneration in Xeroderma Pigmentosum Patients

    Science.gov (United States)

    Reardon, Joyce T.; Bessho, Tadayoshi; Kung, Hsiang Chuan; Bolton, Philip H.; Sancar, Aziz

    1997-08-01

    Xeroderma pigmentosum (XP) patients fail to remove pyrimidine dimers caused by sunlight and, as a consequence, develop multiple cancers in areas exposed to light. The second most common sign, present in 20-30% of XP patients, is a set of neurological abnormalities caused by neuronal death in the central and peripheral nervous systems. Neural tissue is shielded from sunlight-induced DNA damage, so the cause of neurodegeneration in XP patients remains unexplained. In this study, we show that two major oxidative DNA lesions, 8-oxoguanine and thymine glycol, are excised from DNA in vitro by the same enzyme system responsible for removing pyrimidine dimers and other bulky DNA adducts. Our results suggest that XP neurological disease may be caused by defective repair of lesions that are produced in nerve cells by reactive oxygen species generated as by-products of an active oxidative metabolism.

  17. Curcumin protects against cytotoxic and inflammatory effects of quartz particles but causes oxidative DNA damage in a rat lung epithelial cell line

    International Nuclear Information System (INIS)

    Li Hui; Berlo, Damien van; Shi Tingming; Speit, Guenter; Knaapen, Ad M.; Borm, Paul J.A.; Albrecht, Catrin; Schins, Roel P.F.

    2008-01-01

    Chronic inhalation of high concentrations of respirable quartz particles has been implicated in various lung diseases including lung fibrosis and cancer. Generation of reactive oxygen species (ROS) and oxidative stress is considered a major mechanism of quartz toxicity. Curcumin, a yellow pigment from Curcuma longa, has been considered as nutraceutical because of its strong anti-inflammatory, antitumour and antioxidant properties. The aim of our present study was to investigate whether curcumin can protect lung epithelial cells from the cytotoxic, genotoxic and inflammatory effects associated with quartz (DQ12) exposure. Electron paramagnetic resonance (EPR) measurements using the spin-trap DMPO demonstrated that curcumin reduces hydrogen peroxide-dependent hydroxyl-radical formation by quartz. Curcumin was also found to reduce quartz-induced cytotoxicity and cyclooxygenase 2 (COX-2) mRNA expression in RLE-6TN rat lung epithelial cells (RLE). Curcumin also inhibited the release of macrophage inflammatory protein-2 (MIP-2) from RLE cells as observed upon treatment with interleukin-1 beta (IL-1β) and tumour necrosis factor-alpha (TNFα). However, curcumin failed to protect the RLE cells from oxidative DNA damage induced by quartz, as shown by formamidopyrimidine glycosylase (FPG)-modified comet assay and by immunocytochemistry for 8-hydroxydeoxyguanosine. In contrast, curcumin was found to be a strong inducer of oxidative DNA damage itself at non-cytotoxic and anti-inflammatory concentrations. In line with this, curcumin also enhanced the mRNA expression of the oxidative stress response gene heme oxygenase-1 (ho-1). Curcumin also caused oxidative DNA damage in NR8383 rat alveolar macrophages and A549 human lung epithelial cells. Taken together, these observations indicate that one should be cautious in considering the potential use of curcumin in the prevention or treatment of lung diseases associated with quartz exposure

  18. OXIDATIVE STRESS AND VASCULAR DAMAGE IN HYPOXIA PROCESSES. MALONDIALDEHYDE (MDA AS BIOMARKER FOR OXIDATIVE DAMAGE

    Directory of Open Access Journals (Sweden)

    Muñiz P

    2014-05-01

    Full Text Available Changes in the levels oxidative stress biomarkers are related with different diseases such as ischemia/reperfusion, cardiovascular, renal, aging, etc. One of these biomarkers is the malondialdehyde (MDA generated as resulted of the process of lipid peroxidation. This biomarker is increased under conditions of the oxidative stress. Their levels, have been frequently used to measure plasma oxidative damage to lipids by their atherogenic potential. Its half-life high and their reactivity allows it to act both inside and outside of cells and interaction with proteins and DNA involve their role in different pathophysiological processes. This paper presents an analysis of the use of MDA as a biomarker of oxidative stress and its implications associated pathologies such as cardiovascular diseases ago.

  19. Cobalt oxide nanoparticles aggravate DNA damage and cell death in eggplant via mitochondrial swelling and NO signaling pathway.

    Science.gov (United States)

    Faisal, Mohammad; Saquib, Quaiser; Alatar, Abdulrahman A; Al-Khedhairy, Abdulaziz A; Ahmed, Mukhtar; Ansari, Sabiha M; Alwathnani, Hend A; Dwivedi, Sourabh; Musarrat, Javed; Praveen, Shelly

    2016-03-18

    Despite manifold benefits of nanoparticles (NPs), less information on the risks of NPs to human health and environment has been studied. Cobalt oxide nanoparticles (Co3O4-NPs) have been reported to cause toxicity in several organisms. In this study, we have investigated the role of Co3O4-NPs in inducing phytotoxicity, cellular DNA damage and apoptosis in eggplant (Solanum melongena L. cv. Violetta lunga 2). To the best of our knowledge, this is the first report on Co3O4-NPs showing phytotoxicity in eggplant. The data revealed that eggplant seeds treated with Co3O4-NPs for 2 h at a concentration of 1.0 mg/ml retarded root length by 81.5 % upon 7 days incubation in a moist chamber. Ultrastructural analysis by transmission electron microscopy (TEM) demonstrated the uptake and translocation of Co3O4-NPs into the cytoplasm. Intracellular presence of Co3O4-NPs triggered subcellular changes such as degeneration of mitochondrial cristae, abundance of peroxisomes and excessive vacuolization. Flow cytometric analysis of Co3O4-NPs (1.0 mg/ml) treated root protoplasts revealed 157, 282 and 178 % increase in reactive oxygen species (ROS), membrane potential (ΔΨm) and nitric oxide (NO), respectively. Besides, the esterase activity in treated protoplasts was also found compromised. About 2.4-fold greater level of DNA damage, as compared to untreated control was observed in Comet assay, and 73.2 % of Co3O4-NPs treated cells appeared apoptotic in flow cytometry based cell cycle analysis. This study demonstrate the phytotoxic potential of Co3O4-NPs in terms of reduction in seed germination, root growth, greater level of DNA and mitochondrial damage, oxidative stress and cell death in eggplant. The data generated from this study will provide a strong background to draw attention on Co3O4-NPs environmental hazards to vegetable crops.

  20. Accumulation of lipids and oxidatively damaged DNA in hepatocytes exposed to particles

    International Nuclear Information System (INIS)

    Vesterdal, Lise K.; Danielsen, Pernille H.; Folkmann, Janne K.; Jespersen, Line F.; Aguilar-Pelaez, Karin; Roursgaard, Martin; Loft, Steffen; Møller, Peter

    2014-01-01

    Exposure to particles has been suggested to generate hepatosteatosis by oxidative stress mechanisms. We investigated lipid accumulation in cultured human hepatocytes (HepG2) and rat liver after exposure to four different carbon-based particles. HepG2 cells were exposed to particles for 3 h and subsequently incubated for another 18 h to manifest lipid accumulation. In an animal model of metabolic syndrome we investigated the association between intake of carbon black (CB, 14 nm) particles and hepatic lipid accumulation, inflammation and gene expression of Srebp-1, Fasn and Scd-1 involved in lipid synthesis. There was a concentration-dependent increase in intracellular lipid content after exposure to CB in HepG2 cells, which was only observed after co-exposure to oleic/palmitic acid. Similar results were observed in HepG2 cells after exposure to diesel exhaust particles, fullerenes C 60 or pristine single-walled carbon nanotubes. All four types of particles also generated oxidatively damaged DNA, assessed as formamidopyrimidine DNA glycosylase (FPG) sensitive sites, in HepG2 cells after 3 h exposure. The animal model of metabolic syndrome showed increased lipid load in the liver after one oral exposure to 6.4 mg/kg of CB in lean Zucker rats. This was not associated with increased iNOS staining in the liver, indicating that the oral CB exposure was associated with hepatic steatosis rather than steatohepatitis. The lipid accumulation did not seem to be related to increased lipogenesis because there were unaltered gene expression levels in both the HepG2 cells and rat livers. Collectively, exposure to particles is associated with oxidative stress and steatosis in hepatocytes. - Highlights: • Oral exposure to nanosized carbon black was associated with hepatosteatosis in rats. • In vitro studies included carbon black, C 60 , diesel exhaust particles and SWCNTs. • Exposure to particles and free fatty acids increased lipid load in HepG2 cells. • Unaltered expression

  1. Accumulation of lipids and oxidatively damaged DNA in hepatocytes exposed to particles

    Energy Technology Data Exchange (ETDEWEB)

    Vesterdal, Lise K.; Danielsen, Pernille H.; Folkmann, Janne K.; Jespersen, Line F.; Aguilar-Pelaez, Karin; Roursgaard, Martin; Loft, Steffen; Møller, Peter, E-mail: pemo@sund.ku.dk

    2014-01-15

    Exposure to particles has been suggested to generate hepatosteatosis by oxidative stress mechanisms. We investigated lipid accumulation in cultured human hepatocytes (HepG2) and rat liver after exposure to four different carbon-based particles. HepG2 cells were exposed to particles for 3 h and subsequently incubated for another 18 h to manifest lipid accumulation. In an animal model of metabolic syndrome we investigated the association between intake of carbon black (CB, 14 nm) particles and hepatic lipid accumulation, inflammation and gene expression of Srebp-1, Fasn and Scd-1 involved in lipid synthesis. There was a concentration-dependent increase in intracellular lipid content after exposure to CB in HepG2 cells, which was only observed after co-exposure to oleic/palmitic acid. Similar results were observed in HepG2 cells after exposure to diesel exhaust particles, fullerenes C{sub 60} or pristine single-walled carbon nanotubes. All four types of particles also generated oxidatively damaged DNA, assessed as formamidopyrimidine DNA glycosylase (FPG) sensitive sites, in HepG2 cells after 3 h exposure. The animal model of metabolic syndrome showed increased lipid load in the liver after one oral exposure to 6.4 mg/kg of CB in lean Zucker rats. This was not associated with increased iNOS staining in the liver, indicating that the oral CB exposure was associated with hepatic steatosis rather than steatohepatitis. The lipid accumulation did not seem to be related to increased lipogenesis because there were unaltered gene expression levels in both the HepG2 cells and rat livers. Collectively, exposure to particles is associated with oxidative stress and steatosis in hepatocytes. - Highlights: • Oral exposure to nanosized carbon black was associated with hepatosteatosis in rats. • In vitro studies included carbon black, C{sub 60}, diesel exhaust particles and SWCNTs. • Exposure to particles and free fatty acids increased lipid load in HepG2 cells. • Unaltered

  2. Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies

    International Nuclear Information System (INIS)

    Dusinska, Maria; Staruchova, Marta; Horska, Alexandra; Smolkova, Bozena; Collins, Andrew; Bonassi, Stefano; Volkovova, Katarina

    2012-01-01

    Glutathione S-transferases (GSTs) are members of a multigene family of isoenzymes that are important in the control of oxidative stress and in phase II metabolism. Acting non-enzymically, GSTs can modulate signalling pathways of cell proliferation, cell differentiation and apoptosis. Using a molecular epidemiology approach, we have investigated a potential involvement of GSTs in DNA damage processing, specifically the modulation of DNA repair in a group of 388 healthy adult volunteers; 239 with at least 5 years of occupational exposure to asbestos, stone wool or glass fibre, and 149 reference subjects. We measured DNA damage in lymphocytes using the comet assay (alkaline single cell gel electrophoresis): strand breaks (SBs) and alkali-labile sites, oxidised pyrimidines with endonuclease III, and oxidised purines with formamidopyrimidine DNA glycosylase. We also measured GST activity in erythrocytes, and the capacity for base excision repair (BER) in a lymphocyte extract. Polymorphisms in genes encoding three GST isoenzymes were determined, namely deletion of GSTM1 and GSTT1 and single nucleotide polymorphism Ile105Val in GSTP1. Consumption of vegetables and wine correlated negatively with DNA damage and modulated BER. GST activity correlated with oxidised bases and with BER capacity, and differed depending on polymorphisms in GSTP1, GSTT1 and GSTM1. A significantly lower BER rate was associated with the homozygous GSTT1 deletion in all asbestos site subjects and in the corresponding reference group. Multifactorial analysis revealed effects of sex and exposure in GSTP1 Ile/Val heterozygotes but not in Ile/Ile homozygotes. These variants affected also SBs levels, mainly by interactions of GSTP1 genotype with exposure, with sex, and with smoking habit; and by an interaction between sex and smoking. Our results show that GST polymorphisms and GST activity can apparently influence DNA stability and repair of oxidised bases, suggesting a potential new role for these

  3. Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies

    Energy Technology Data Exchange (ETDEWEB)

    Dusinska, Maria, E-mail: Maria.DUSINSKA@nilu.no [CEE-Health Effects Group, NILU - Norwegian Institute for Air Research, Kjeller (Norway); Staruchova, Marta; Horska, Alexandra [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia); Smolkova, Bozena [Laboratory of Cancer Genetics, Cancer Research Institute of the Slovak Academy of Sciences, Bratislava (Slovakia); Collins, Andrew [Department of Nutrition, Faculty of Medicine, University of Oslo (Norway); Bonassi, Stefano [Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Rome (Italy); Volkovova, Katarina [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia)

    2012-08-01

    Glutathione S-transferases (GSTs) are members of a multigene family of isoenzymes that are important in the control of oxidative stress and in phase II metabolism. Acting non-enzymically, GSTs can modulate signalling pathways of cell proliferation, cell differentiation and apoptosis. Using a molecular epidemiology approach, we have investigated a potential involvement of GSTs in DNA damage processing, specifically the modulation of DNA repair in a group of 388 healthy adult volunteers; 239 with at least 5 years of occupational exposure to asbestos, stone wool or glass fibre, and 149 reference subjects. We measured DNA damage in lymphocytes using the comet assay (alkaline single cell gel electrophoresis): strand breaks (SBs) and alkali-labile sites, oxidised pyrimidines with endonuclease III, and oxidised purines with formamidopyrimidine DNA glycosylase. We also measured GST activity in erythrocytes, and the capacity for base excision repair (BER) in a lymphocyte extract. Polymorphisms in genes encoding three GST isoenzymes were determined, namely deletion of GSTM1 and GSTT1 and single nucleotide polymorphism Ile105Val in GSTP1. Consumption of vegetables and wine correlated negatively with DNA damage and modulated BER. GST activity correlated with oxidised bases and with BER capacity, and differed depending on polymorphisms in GSTP1, GSTT1 and GSTM1. A significantly lower BER rate was associated with the homozygous GSTT1 deletion in all asbestos site subjects and in the corresponding reference group. Multifactorial analysis revealed effects of sex and exposure in GSTP1 Ile/Val heterozygotes but not in Ile/Ile homozygotes. These variants affected also SBs levels, mainly by interactions of GSTP1 genotype with exposure, with sex, and with smoking habit; and by an interaction between sex and smoking. Our results show that GST polymorphisms and GST activity can apparently influence DNA stability and repair of oxidised bases, suggesting a potential new role for these

  4. DNA damage in Populus tremuloides clones exposed to elevated O3

    International Nuclear Information System (INIS)

    Tai, Helen H.; Percy, Kevin E.; Karnosky, David F.

    2010-01-01

    The effects of elevated concentrations of atmospheric tropospheric ozone (O 3 ) on DNA damage in five trembling aspen (Populus tremuloides Michx.) clones growing in a free-air enrichment experiment in the presence and absence of elevated concentrations of carbon dioxide (CO 2 ) were examined. Growing season mean hourly O 3 concentrations were 36.3 and 47.3 ppb for ambient and elevated O 3 plots, respectively. The 4th highest daily maximum 8-h ambient and elevated O 3 concentrations were 79 and 89 ppb, respectively. Elevated CO 2 averaged 524 ppm (+150 ppm) over the growing season. Exposure to O 3 and CO 2 in combination with O 3 increased DNA damage levels above background as measured by the comet assay. Ozone-tolerant clones 271 and 8L showed the highest levels of DNA damage under elevated O 3 compared with ambient air; whereas less tolerant clone 216 and sensitive clones 42E and 259 had comparably lower levels of DNA damage with no significant differences between elevated O 3 and ambient air. Clone 8L was demonstrated to have the highest level of excision DNA repair. In addition, clone 271 had the highest level of oxidative damage as measured by lipid peroxidation. The results suggest that variation in cellular responses to DNA damage between aspen clones may contribute to O 3 tolerance or sensitivity. - Ozone tolerant clones and sensitive Populus tremuloides clones show differences in DNA damage and repair.

  5. Oxidative damage to biological macromolecules in Prague bus drivers and garagemen: impact of air pollution and genetic polymorphisms.

    Science.gov (United States)

    Bagryantseva, Yana; Novotna, Bozena; Rossner, Pavel; Chvatalova, Irena; Milcova, Alena; Svecova, Vlasta; Lnenickova, Zdena; Solansky, Ivo; Sram, Radim J

    2010-11-10

    DNA integrity was investigated in the lymphocytes of 50 bus drivers, 20 garagemen and 50 controls using the comet assay with excision repair enzymes. In parallel, 8-oxo-7,8-dihydro-2'-deoxyguanosine and 15-F(2t)-isoprostane levels in the urine and protein carbonyl levels in the plasma were assessed as markers of oxidative damage to DNA, lipids and proteins. Exposure to carcinogenic polycyclic aromatic hydrocarbons (cPAHs) and volatile compounds was measured by personal samplers for 48 and 24h, respectively, before the collection of biological specimens. Both exposed groups exhibited a higher levels of DNA instability and oxidative damage to biological macromolecules than the controls. The incidence of oxidized lesions in lymphocyte DNA, but not the urinary levels of 8-oxodG, correlated with exposure to benzene and triglycerides increased this damage. Oxidative damage to lipids and proteins was associated with exposure to cPAHs and the lipid peroxidation levels positively correlated with age and LDL cholesterol, and negatively with vitamin C. The carriers of at least one variant hOGG1 (Cys) allele tended to higher oxidative damage to lymphocyte DNA than those with the wild genotype, while XPD23 (Gln/Gln) homozygotes were more susceptible to the induction of DNA strand breaks. In contrast, GSTM1 null variant seemed to protect DNA integrity. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  6. The role of mitochondrial DNA damage at skeletal muscle oxidative stress on the development of type 2 diabetes.

    Science.gov (United States)

    Dos Santos, Julia Matzenbacher; de Oliveira, Denise Silva; Moreli, Marcos Lazaro; Benite-Ribeiro, Sandra Aparecida

    2018-04-20

    Reduced cellular response to insulin in skeletal muscle is one of the major components of the development of type 2 diabetes (T2D). Mitochondrial dysfunction involves in the accumulation of toxic reactive oxygen species (ROS) that leads to insulin resistance. The aim of this study was to verify the involvement of mitochondrial DNA damage at ROS generation in skeletal muscle during development of T2D. Wistar rats were fed a diet containing 60% fat over 8 weeks and at day 14 a single injection of STZ (25 mg/kg) was administered (T2D-induced). Control rats received standard food and an injection of citrate buffer. Blood and soleus muscle were collected. Abdominal fat was quantified as well as glucose, triglyceride, LDL, HDL, and total cholesterol in plasma and mtDNA copy number, cytochrome b (cytb) mRNA, 8-hydroxyguanosine, and 8-isoprostane (a marker of ROS) in soleus muscle. T2D-induced animal presented similar characteristics to humans that develop T2D such as changes in blood glucose, abdominal fat, LDL, HDL and cholesterol total. In soleus muscle 8-isoprostane, mtDNA copy number and 8-hydroxyguanosine were increased, while cytb mRNA was decreased in T2D. Our results suggest that in the development of T2D, when risks factors of T2D are present, intracellular oxidative stress increases in skeletal muscle and is associated with a decrease in cytb transcription. To overcome this process mtDNA increased but due to the proximity of ROS generation, mtDNA remains damaged by oxidation leading to an increase in ROS in a vicious cycle accounting to the development of insulin resistance and further T2D.

  7. Metabolic Imbalance Associated with Methylation Dysregulation and Oxidative Damage in Children with Autism

    Science.gov (United States)

    Melnyk, Stepan; Fuchs, George J.; Schulz, Eldon; Lopez, Maya; Kahler, Stephen G.; Fussell, Jill J.; Bellando, Jayne; Pavliv, Oleksandra; Rose, Shannon; Seidel, Lisa; Gaylor, David W.

    2012-01-01

    Oxidative stress and abnormal DNA methylation have been implicated in the pathophysiology of autism. We investigated the dynamics of an integrated metabolic pathway essential for cellular antioxidant and methylation capacity in 68 children with autism, 54 age-matched control children and 40 unaffected siblings. The metabolic profile of unaffected siblings differed significantly from case siblings but not from controls. Oxidative protein/DNA damage and DNA hypomethylation (epigenetic alteration) were found in autistic children but not paired siblings or controls. These data indicate that the deficit in antioxidant and methylation capacity is specific for autism and may promote cellular damage and altered epigenetic gene expression. Further, these results suggest a plausible mechanism by which pro-oxidant environmental stressors may modulate genetic predisposition to autism. PMID:21519954

  8. RPA physically interacts with the human DNA glycosylase NEIL1 to regulate excision of oxidative DNA base damage in primer-template structures.

    Science.gov (United States)

    Theriot, Corey A; Hegde, Muralidhar L; Hazra, Tapas K; Mitra, Sankar

    2010-06-04

    The human DNA glycosylase NEIL1, activated during the S-phase, has been shown to excise oxidized base lesions in single-strand DNA substrates. Furthermore, our previous work demonstrating functional interaction of NEIL1 with PCNA and flap endonuclease 1 (FEN1) suggested its involvement in replication-associated repair. Here we show interaction of NEIL1 with replication protein A (RPA), the heterotrimeric single-strand DNA binding protein that is essential for replication and other DNA transactions. The NEIL1 immunocomplex isolated from human cells contains RPA, and its abundance in the complex increases after exposure to oxidative stress. NEIL1 directly interacts with the large subunit of RPA (K(d) approximately 20 nM) via the common interacting interface (residues 312-349) in NEIL1's disordered C-terminal region. RPA inhibits the base excision activity of both wild-type NEIL1 (389 residues) and its C-terminal deletion CDelta78 mutant (lacking the interaction domain) for repairing 5-hydroxyuracil (5-OHU) in a primer-template structure mimicking the DNA replication fork. This inhibition is reduced when the damage is located near the primer-template junction. Contrarily, RPA moderately stimulates wild-type NEIL1 but not the CDelta78 mutant when 5-OHU is located within the duplex region. While NEIL1 is inhibited by both RPA and Escherichia coli single-strand DNA binding protein, only inhibition by RPA is relieved by PCNA. These results showing modulation of NEIL1's activity on single-stranded DNA substrate by RPA and PCNA support NEIL1's involvement in repairing the replicating genome. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Association between iron level, glucose impairment and increased DNA damage during pregnancy.

    Science.gov (United States)

    Zein, Salam; Rachidi, Samar; Shami, Nadine; Sharara, Iman; Cheikh-Ali, Khawla; Gauchez, Anne-Sophie; Moulis, Jean-Marc; Ayoubi, Jean-Marc; Salameh, Pascale; Hininger-Favier, Isabelle

    2017-09-01

    Elevated circulating ferritin has been reported to increase the risk of gestational diabetes mellitus (GDM). When high ferritin translates into high iron stores, iron excess is also a condition leading to free radical damage. We aimed to evaluate the relationship between oxidative stress (OS) induced by iron status and GDM risk in non iron-supplemented pregnant women. This was a pilot observational study conducted on 93 non-anemic pregnant women. Iron status was assessed at the first trimester of gestation. Blood sampling was done at 24-28 weeks' gestation for oral glucose tolerance test (OGTT), insulin and biological markers of oxidative damage tests. A significant increase in DNA damage was found in patients who developed GDM. Women with elevated DNA damage had a six-fold increased risk of developing GDM (Exp (B)=6.851, P=0.038; 95% CI [1.108-42.375]). The serum ferritin levels at first trimester were significantly correlated to lipid peroxidation (rho=0.24, p=0.012). The stratified analysis suggests that ferritin is a modifying factor for the correlation of oxidative stress (OS) and glucose intolerance. Moderate ferritin levels due to iron intake without iron-supplement, at early pregnancy is a modifying factor for the correlation of oxidative damage and glucose intolerance in pregnant women. Larger studies to evaluate the risk of food iron intake induced increased oxidative damage in offspring are warranted to propose nutrition advice regarding iron intake in women with a high risk of GDM. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Exposure to 1800 MHz radiofrequency electromagnetic radiation induces oxidative DNA base damage in a mouse spermatocyte-derived cell line.

    Science.gov (United States)

    Liu, Chuan; Duan, Weixia; Xu, Shangcheng; Chen, Chunhai; He, Mindi; Zhang, Lei; Yu, Zhengping; Zhou, Zhou

    2013-03-27

    Whether exposure to radiofrequency electromagnetic radiation (RF-EMR) emitted from mobile phones can induce DNA damage in male germ cells remains unclear. In this study, we conducted a 24h intermittent exposure (5 min on and 10 min off) of a mouse spermatocyte-derived GC-2 cell line to 1800 MHz Global System for Mobile Communication (GSM) signals in GSM-Talk mode at specific absorption rates (SAR) of 1 W/kg, 2 W/kg or 4 W/kg. Subsequently, through the use of formamidopyrimidine DNA glycosylase (FPG) in a modified comet assay, we determined that the extent of DNA migration was significantly increased at a SAR of 4 W/kg. Flow cytometry analysis demonstrated that levels of the DNA adduct 8-oxoguanine (8-oxoG) were also increased at a SAR of 4 W/kg. These increases were concomitant with similar increases in the generation of reactive oxygen species (ROS); these phenomena were mitigated by co-treatment with the antioxidant α-tocopherol. However, no detectable DNA strand breakage was observed by the alkaline comet assay. Taking together, these findings may imply the novel possibility that RF-EMR with insufficient energy for the direct induction of DNA strand breaks may produce genotoxicity through oxidative DNA base damage in male germ cells. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Oxidative stress and DNA damage caused by the urban air pollutant 3-NBA and its isomer 2-NBA in human lung cells analyzed with three independent methods.

    Science.gov (United States)

    Nagy, Eszter; Johansson, Clara; Zeisig, Magnus; Möller, Lennart

    2005-11-15

    The air pollutant 3-nitrobenzanthrone (3-NBA), emitted in diesel exhaust, is a potent mutagen and genotoxin. 3-NBA can isomerise to 2-nitrobenzanthrone (2-NBA), which can become more than 70-fold higher in concentration in ambient air. In this study, three independent methods have been employed to evaluate the oxidative stress and genotoxicity of 2-NBA compared to 3-NBA in the human A549 lung cell line. HPLC-EC/UV was applied for measurements of oxidative damage in the form of 8-oxo-2'-deoxyguanosine (8-oxodG), (32)P-HPLC for measurements of lipophilic DNA-adducts, and the Comet assay to measure a variety of DNA lesions, including oxidative stress. No significant oxidative damage from either isomer was found regarding formation of 8-oxodG analysed using HPLC-EC/UV. However, the Comet assay (with FPG-treatment), which is more sensitive and detects more types of damages compared to HPLC-EC/UV, showed a significant effect from both 3-NBA and 2-NBA. (32)P-HPLC revealed a strong DNA-adduct formation from both 3-NBA and 2-NBA, and also a significant difference between both isomers compared to negative control. These results clearly show that 2-NBA has a genotoxic potential. Even if the DNA-adduct forming capacity and the amount of DNA lesions measured with the (32)P-HPLC and Comet assay is about one third of 3-NBA, the high abundance of 2-NBA in ambient air calls for further investigation and evaluation of its health hazard.

  12. Histone peptide AKRHRK enhances H2O2-induced DNA damage and alters its site specificity

    International Nuclear Information System (INIS)

    Midorikawa, Kaoru; Murata, Mariko; Kawanishi, Shosuke

    2005-01-01

    Histone proteins are involved in compaction of DNA and the protection of cells from oxygen toxicity. However, several studies have demonstrated that the metal-binding histone reacts with H 2 O 2 , leading to oxidative damage to a nucleobase. We investigated whether histone can accelerate oxidative DNA damage, using a minimal model for the N-terminal tail of histone H4, CH 3 CO-AKRHRK-CONH 2 , which has a metal-binding site. This histone peptide enhanced DNA damage induced by H 2 O 2 and Cu(II), especially at cytosine residues, and induced additional DNA cleavage at the 5'-guanine of GGG sequences. The peptide also enhanced the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine and ESR spin-trapping signal from H 2 O 2 and Cu(II). Cyclic redox reactions involving histone-bound Cu(II) and H 2 O 2 , may give rise to multiple production of radicals leading to multiple hits in DNA. It is noteworthy that the histone H4 peptide with specific sequence AKRHRK can cause DNA damage rather than protection under metal-overloaded condition

  13. Cross-Talk between Carbon Metabolism and the DNA Damage Response in S. cerevisiae

    Directory of Open Access Journals (Sweden)

    Kobi J. Simpson-Lavy

    2015-09-01

    Full Text Available Yeast cells with DNA damage avoid respiration, presumably because products of oxidative metabolism can be harmful to DNA. We show that DNA damage inhibits the activity of the Snf1 (AMP-activated protein kinase (AMPK, which activates expression of genes required for respiration. Glucose and DNA damage upregulate SUMOylation of Snf1, catalyzed by the SUMO E3 ligase Mms21, which inhibits SNF1 activity. The DNA damage checkpoint kinases Mec1/ATR and Tel1/ATM, as well as the nutrient-sensing protein kinase A (PKA, regulate Mms21 activity toward Snf1. Mec1 and Tel1 are required for two SNF1-regulated processes—glucose sensing and ADH2 gene expression—even without exogenous genotoxic stress. Our results imply that inhibition of Snf1 by SUMOylation is a mechanism by which cells lower their respiration in response to DNA damage. This raises the possibility that activation of DNA damage checkpoint mechanisms could contribute to aerobic fermentation (Warburg effect, a hallmark of cancer cells.

  14. The influence of selenium status on body composition, oxidative DNA damage and total antioxidant capacity in newly diagnosed type 2 diabetes mellitus: A case-control study.

    Science.gov (United States)

    Othman, Fatimah Binti; Mohamed, Hamid Jan Bin Jan; Sirajudeen, K N S; Noh, Mohd Fairulnizal B Md; Rajab, Nor Fadilah

    2017-09-01

    Selenium is involved in the complex system of defense against oxidative stress in diabetes through its biological function of selenoproteins and the antioxidant enzyme. A case-control study was carried out to determine the association of plasma selenium with oxidative stress and body composition status presented in Type 2 Diabetes Mellitus (T2DM) patient and healthy control. This study involved 82 newly diagnosed T2DM patients and 82 healthy controls. Plasma selenium status was determined with Graphite Furnace Atomic Absorption Spectrometry. Body Mass Index, total body fat and visceral fat was assessed for body composition using Body Composition Analyzer (TANITA). Oxidative DNA damage and total antioxidant capacity were determined for oxidative stress biomarker status. In age, gender and BMI adjustment, no significant difference of plasma selenium level between T2DM and healthy controls was observed. There was as a significant difference of Oxidative DNA damage and total antioxidant capacity between T2DM patients and healthy controls with tail DNA% 20.62 [95% CI: 19.71,21.49] (T2DM), 17.67 [95% CI: 16.87,18.56] (control); log tail moment 0.41[95% CI: 0.30,0.52] (T2DM), 0.41[95% CI: 0.30,0.52] (control); total antioxidant capacity 0.56 [95% CI: 0.54,0.58] (T2DM), 0.60 [95% CI: 0.57,0.62] (control). Waist circumference, BMI, visceral fat, body fat and oxidative DNA damage in the T2DM group were significantly lower in the first plasma selenium tertile (38.65-80.90μg/L) compared to the second (80.91-98.20μg/L) and the third selenium tertiles (98.21-158.20μg/L). A similar trend, but not statistically significant, was observed in the control group. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Weight increase and overweight are associated with DNA oxidative damage in skeletal muscle.

    Science.gov (United States)

    de la Maza, María-Pía; Olivares, Daniela; Hirsch, Sandra; Sierralta, Walter; Gattás, Vivien; Barrera, Gladys; Bunout, Daniel; Leiva, Laura; Fernández, Mireya

    2006-12-01

    Weight maintenance within normal standards is recommended for prevention of conditions associated with oxidative injury. To compare oxidative damage in a post mitotic tissue, between adults differing in long-term energy balance. During hernia surgery, a sample of skeletal muscle was obtained in 17 non-obese adults. Subjects were divided into two groups according to their self-reported weight change: weight maintainers (WM) reported 5kg increment. Muscle immunohistochemistry for 8-hydroxy-deoxyguanosine (8OHdG), 4-Hydroxy-2-nonenal (4HNE), and TNF-alpha, as markers of oxidative injury and inflammation, were performed. As known positive controls for oxidative injury, we included 10 elderly subjects (66-101yr). Anthropometric measures and blood samples for clinical laboratory and serum cytokines (TNF-alpha and IL-6) were obtained. 8OHdG was higher in WG compared with WM (149.1+/-16.2 versus 117.8+/-29.5, P=0.03), and was associated with anthropometric indicators of fat accumulation. 4HNE was similar in WG compared with WM (10.9+/-7.6 versus 9.8+/-6.3) but noticeably higher in elderly subjects (21.5+/-15.3, P=0.059). TNF-alpha protein in WG was higher compared with WM (114.0+/-41.7 versus 70.1+/-23.3, P=0.025), and was associated with weight increase. Moderate self-reported weight increase, and body fat accumulation, suggesting long-term positive energy balance is associated with muscle DNA oxidative injury and inflammation.

  16. Apple Flavonoids Suppress Carcinogen-Induced DNA Damage in Normal Human Bronchial Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Vazhappilly Cijo George

    2017-01-01

    Full Text Available Scope. Human neoplastic transformation due to DNA damage poses an increasing global healthcare concern. Maintaining genomic integrity is crucial for avoiding tumor initiation and progression. The present study aimed to investigate the efficacy of an apple flavonoid fraction (AF4 against various carcinogen-induced toxicity in normal human bronchial epithelial cells and its mechanism of DNA damage response and repair processes. Methods and Results. AF4-pretreated cells were exposed to nicotine-derived nitrosamine ketones (NNK, NNK acetate (NNK-Ae, methotrexate (MTX, and cisplatin to validate cytotoxicity, total reactive oxygen species, intracellular antioxidants, DNA fragmentation, and DNA tail damage. Furthermore, phosphorylated histone (γ-H2AX and proteins involved in DNA damage (ATM/ATR, Chk1, Chk2, and p53 and repair (DNA-PKcs and Ku80 mechanisms were evaluated by immunofluorescence and western blotting, respectively. The results revealed that AF4-pretreated cells showed lower cytotoxicity, total ROS generation, and DNA fragmentation along with consequent inhibition of DNA tail moment. An increased level of γ-H2AX and DNA damage proteins was observed in carcinogen-treated cells and that was significantly (p≤0.05 inhibited in AF4-pretreated cells, in an ATR-dependent manner. AF4 pretreatment also facilitated the phosphorylation of DNA-PKcs and thus initiation of repair mechanisms. Conclusion. Apple flavonoids can protect in vitro oxidative DNA damage and facilitate repair mechanisms.

  17. Melanin photosensitizes ultraviolet light (UVC) DNA damage in pigmented cells

    International Nuclear Information System (INIS)

    Huselton, C.A.; Hill, H.Z.

    1990-01-01

    Melanins, pigments of photoprotection and camouflage, are very photoreactive and can both absorb and emit active oxygen species. Nevertheless, black skinned individuals rarely develop skin cancer and melanin is assumed to act as a solar screen. Since DNA is the target for solar carcinogenesis, the effect of melanin on Ultraviolet (UV)-induced thymine lesions was examined in mouse melanoma and carcinoma cells that varied in melanin content. Cells prelabeled with 14C-dThd were irradiated with UVC; DNA was isolated, purified, degraded to bases by acid hydrolysis and analyzed by HPLC. Thymine dimers were detected in all of the extracts of irradiated cells. Melanotic and hypomelanotic but not mammary carcinoma cell DNA from irradiated cells contained hydrophilic thymine derivatives. The quantity of these damaged bases was a function of both the UVC dose and the cellular melanin content. One such derivative was identified by gas chromatography-mass spectroscopy as thymine glycol. The other appears to be derived from thymine glycol by further oxidation during acid hydrolysis of the DNA. The finding of oxidative DNA damage in melanin-containing cells suggests that melanin may be implicated in the etiology of caucasian skin cancer, particularly melanoma. Furthermore, the projected decrease in stratospheric ozone could impact in an unanticipated deleterious manner on dark-skinned individuals

  18. Angiotensin II type 1a receptor-deficient mice develop angiotensin II-induced oxidative stress and DNA damage without blood pressure increase.

    Science.gov (United States)

    Zimnol, Anna; Amann, Kerstin; Mandel, Philipp; Hartmann, Christina; Schupp, Nicole

    2017-12-01

    Hypertensive patients have an increased risk of developing kidney cancer. We have shown in vivo that besides elevating blood pressure, angiotensin II causes DNA damage dose dependently. Here, the role of blood pressure in the formation of DNA damage is studied. Mice lacking one of the two murine angiotensin II type 1 receptor (AT1R) subtypes, AT1aR, were equipped with osmotic minipumps, delivering angiotensin II during 28 days. Parameters of oxidative stress and DNA damage of kidneys and hearts of AT1aR-knockout mice were compared with wild-type (C57BL/6) mice receiving angiotensin II, and additionally, with wild-type mice treated with candesartan, an antagonist of both AT1R subtypes. In wild-type mice, angiotensin II induced hypertension, reduced kidney function, and led to a significant formation of reactive oxygen species (ROS). Furthermore, genomic damage was markedly increased in this group. All these responses to angiotensin II could be attenuated by concurrent administration of candesartan. In AT1aR-deficient mice treated with angiotensin II, systolic pressure was not increased, and renal function was not affected. However, angiotensin II still led to an increase of ROS in kidneys and hearts of these animals. Additionally, genomic damage in the form of double-strand breaks was significantly induced in kidneys of AT1aR-deficient mice. Our results show that angiotensin II induced ROS production and DNA damage even without the presence of AT1aR and independently of blood pressure changes. Copyright © 2017 the American Physiological Society.

  19. DNA damage by Auger emitters

    International Nuclear Information System (INIS)

    Martin, R.F.; d'Cunha, Glenn; Gibbs, Richard; Murray, Vincent; Pardee, Marshall; Allen, B.J.

    1988-01-01

    125 I atoms can be introduced at specific locations along a defined DNA target molecule, either by site-directed incorporation of an 125 I-labelled deoxynucleotide or by binding of an 125 I-labelled sequence-selective DNA ligand. After allowing accumulation of 125 I decay-induced damage to the DNA, application of DNA sequencing techniques enables positions of strand breaks to be located relative to the site of decay, at a resolution corresponding to the distance between adjacent nucleotides [0.34 nm]. Thus, DNA provides a molecular framework to analyse the extent of damage following [averaged] individual decay events. Results can be compared with energy deposition data generated by computer-simulation methods developed by Charlton et al. The DNA sequencing technique also provides information about the chemical nature of the termini of the DNA chains produced following Auger decay-induced damage. In addition to reviewing the application of this approach to the analysis of 125 I decay induced DNA damage, some more recent results obtained by using 67 Ga are also presented. (author)

  20. Reduction of DNA damage induced by titanium dioxide nanoparticles through Nrf2 in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhiqin [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Department of Laboratory Diagnosis, Hebei Medical University, Shijiazhuang (China); Niu, Yujie [Department of Occupational Health and Environmental Health, Hebei Medical University, Shijiazhuang (China); Wang, Qian [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Shi, Lei [Department of Occupational Health and Environmental Health, Hebei Medical University, Shijiazhuang (China); Guo, Huicai; Liu, Yi; Zhu, Yue [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Liu, Shufeng; Liu, Chao [Hebei Keylab of Laboratory Animal Science, Shijiazhuang (China); Chen, Xin [Xiumen Community Health Service Centre, Shijiazhuang (China); Zhang, Rong, E-mail: rongzhang@hebmu.edu.cn [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Hebei Keylab of Laboratory Animal Science, Shijiazhuang (China)

    2015-11-15

    Highlights: • Nrf2 signals were partly responsible for the DNA damage induced by Nano-TiO{sub 2}. • Nrf2 loss could aggravate the DNA damage induced by Nano-TiO{sub 2}. • Acquired Nrf2 decreased the susceptibility to DNA damage induced by Nano-TiO{sub 2}. - Abstract: Titanium dioxide nanoparticles (Nano-TiO{sub 2}) are widely used to additives in cosmetics, pharmaceutical, paints and foods. Recent studies have demonstrated that Nano-TiO{sub 2} induces DNA damage and increased the risk of cancer and the mechanism might relate with oxidative stress. The aim of this study was to evaluate the effects of Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), an anti-oxidative mediator, on DNA damage induced by Nano-TiO{sub 2}. Wildtype, Nrf2 knockout (Nrf2(-/-)) and tert-butylhydroquinone (tBHQ) pre-treated HepG2 cells and mice were treated with Nano-TiO{sub 2}. And then the oxidative stress and DNA damage were evaluated. Our data showed that DNA damage, reactive oxygen species (ROS) generation and MDA content in Nano-TiO{sub 2} exposed cells were significantly increased than those of control in dose dependent manners. Nrf2/ARE droved the downstream genes including NAD(P)H dehydrogenase [quinine] 1(NQO1), heme oxygenase 1 (HO-1) and glutamate-cysteine ligase catalytic subunit (GCLC) expression were significantly higher in wildtype HepG2 cells after Nano-TiO{sub 2} treatment. After treatment with Nano-TiO{sub 2}, the DNA damages were significantly increased in Nrf(-/-) cells and mice whereas significantly decreased in tBHQ pre-treatment cells and mice, compared with the wildtype HepG2 cells and mice, respectively. Our results indicated that the acquired of Nrf2 leads to a decreased susceptibility to DNA damages induction by Nano-TiO{sub 2} and decreasing of risk of cancer which would provide a strategy for a more efficacious sensitization of against of Nano-TiO{sub 2} toxication.

  1. The DNA damage response during mitosis

    International Nuclear Information System (INIS)

    Heijink, Anne Margriet; Krajewska, Małgorzata; Vugt, Marcel A.T.M. van

    2013-01-01

    Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed

  2. The DNA damage response during mitosis

    Energy Technology Data Exchange (ETDEWEB)

    Heijink, Anne Margriet; Krajewska, Małgorzata; Vugt, Marcel A.T.M. van, E-mail: m.vugt@umcg.nl

    2013-10-15

    Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed.

  3. Complex DNA Damage: A Route to Radiation-Induced Genomic Instability and Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Ifigeneia V. Mavragani

    2017-07-01

    Full Text Available Cellular effects of ionizing radiation (IR are of great variety and level, but they are mainly damaging since radiation can perturb all important components of the cell, from the membrane to the nucleus, due to alteration of different biological molecules ranging from lipids to proteins or DNA. Regarding DNA damage, which is the main focus of this review, as well as its repair, all current knowledge indicates that IR-induced DNA damage is always more complex than the corresponding endogenous damage resulting from endogenous oxidative stress. Specifically, it is expected that IR will create clusters of damage comprised of a diversity of DNA lesions like double strand breaks (DSBs, single strand breaks (SSBs and base lesions within a short DNA region of up to 15–20 bp. Recent data from our groups and others support two main notions, that these damaged clusters are: (1 repair resistant, increasing genomic instability (GI and malignant transformation and (2 can be considered as persistent “danger” signals promoting chronic inflammation and immune response, causing detrimental effects to the organism (like radiation toxicity. Last but not least, the paradigm shift for the role of radiation-induced systemic effects is also incorporated in this picture of IR-effects and consequences of complex DNA damage induction and its erroneous repair.

  4. Recruitment of RNA polymerase II cofactor PC4 to DNA damage sites

    Science.gov (United States)

    Mortusewicz, Oliver; Roth, Wera; Li, Na; Cardoso, M. Cristina; Meisterernst, Michael; Leonhardt, Heinrich

    2008-01-01

    The multifunctional nuclear protein positive cofactor 4 (PC4) is involved in various cellular processes including transcription, replication, and chromatin organization. Recently, PC4 has been identified as a suppressor of oxidative mutagenesis in Escherichia coli and Saccharomyces cerevisiae. To investigate a potential role of PC4 in mammalian DNA repair, we used a combination of live cell microscopy, microirradiation, and fluorescence recovery after photobleaching analysis. We found a clear accumulation of endogenous PC4 at DNA damage sites introduced by either chemical agents or laser microirradiation. Using fluorescent fusion proteins and specific mutants, we demonstrated that the rapid recruitment of PC4 to laser-induced DNA damage sites is independent of poly(ADP-ribosyl)ation and γH2AX but depends on its single strand binding capacity. Furthermore, PC4 showed a high turnover at DNA damages sites compared with the repair factors replication protein A and proliferating cell nuclear antigen. We propose that PC4 plays a role in the early response to DNA damage by recognizing single-stranded DNA and may thus initiate or facilitate the subsequent steps of DNA repair. PMID:19047459

  5. Radiation-induced DNA damage as a function of DNA hydration

    International Nuclear Information System (INIS)

    Swarts, S.G.; Miao, L.; Wheeler, K.T.; Sevilla, M.D.; Becker, D.

    1995-01-01

    Radiation-induced DNA damage is produced from the sum of the radicals generated by the direct ionization of the DNA (direct effect) and by the reactions of the DNA with free radicals formed in the surrounding environment (indirect effect). The indirect effect has been believed to be the predominant contributor to radiation-induced intracellular DNA damage, mainly as the result of reactions of bulk water radicals (e.g., OH·) with DNA. However, recent evidence suggests that DNA damage, derived from the irradiation of water molecules that are tightly bound in the hydration layer, may occur as the result of the transfer of electron-loss centers (e.g. holes) and electrons from these water molecules to the DNA. Since this mechanism for damaging DNA more closely parallels that of the direct effect, the irradiation of these tightly bound water molecules may contribute to a quasi-direct effect. These water molecules comprise a large fraction of the water surrounding intracellular DNA and could account for a significant proportion of intracellular radiation-induced DNA damage. Consequently, the authors have attempted to characterize this quasi-direct effect to determine: (1) the extent of the DNA hydration layer that is involved with this effect, and (2) what influence this effect has on the types and quantities of radiation-induced DNA damage

  6. The Protective Effect of Whole Honey and Phenolic Extract on Oxidative DNA Damage in Mice Lymphocytes Using Comet Assay.

    Science.gov (United States)

    Cheng, Ni; Wang, Yuan; Cao, Wei

    2017-12-01

    In this study, the antioxidant activity and the protective effect against hydrogen peroxide-induced DNA damage were assessed for five honeys of different botanical origin. Seven phenolic acids were detected in the honey samples. Ferulic acid was the most abundant phenolic acid detected in longan honey, jujube honey and buckwheat honey. Ellagic acid, p-hydroxybenzoic acid and protocatechuic acid were the main phenolic acids detected in vitex honey. Of all honey samples tested, the highest total phenolic content and antioxidant activity were found in buckwheat honey, whereas the lowest total phenolic content and antioxidant activity were found in locust honey. Treatment with hydrogen peroxide induced a 62% increase in tail DNA in mice lymphocytes, and all studied honeys significantly inhibited this effect (P Phenolic extracts of honey displayed greater protective effects than whole honey in comet assay. The hydrogen peroxide-generated increase in 8-hydroxy-2-deoxyguanosine (8-OHdG) was effectively inhibited by the honeys studied (P phenolic acids of honey can penetrate into lymphocytes and protect DNA from oxidative damage by scavenging hydrogen peroxide and/or chelating ferrous ions.

  7. DNA Damage Protecting Activity and Antioxidant Potential of Launaea taraxacifolia Leaves Extract.

    Science.gov (United States)

    Adinortey, Michael Buenor; Ansah, Charles; Weremfo, Alexander; Adinortey, Cynthia Ayefoumi; Adukpo, Genevieve Etornam; Ameyaw, Elvis Ofori; Nyarko, Alexander Kwadwo

    2018-01-01

    The leaf extract of Launaea taraxacifolia commonly known as African Lettuce is used locally to treat dyslipidemia and liver diseases, which are associated with oxidative stress. Methanol extract from L. taraxacifolia leaves was tested for its antioxidant activity and its ability to protect DNA from oxidative damage. In vitro antioxidant potential of the leaf extract was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO), and hydroxyl (OH) radical scavenging assays. Ferric reducing power, total antioxidant capacity (TAC), metal chelating, and anti-lipid peroxidation ability of the extract were also examined using gallic acid, ascorbic acid, citric acid, and ethylenediaminetetraacetic acid as standards. L. taraxacifolia leaves extract showed antioxidant activity with IC 50 values of 16.18 μg/ml (DPPH), 123.3 μg/ml (NO), 128.2 μg/ml (OH radical), 97.94 μg/ml (metal chelating), 80.28 μg/ml (TAC), and 23 μg/ml (anti-lipid peroxidation activity). L. taraxacifolia leaves extract exhibited a strong capability for DNA damage protection at 20 mg/ml concentration. These findings suggest that the methanolic leaf extract of L. taraxacifolia could be used as a natural antioxidant and also as a preventive therapy against diseases such as arteriosclerosis associated with DNA damage.

  8. Antiretroviral therapy-induced insulin resistance and oxidative deoxy nucleic acid damage in human immunodeficiency virus-1 patients

    Directory of Open Access Journals (Sweden)

    Vaishali Kolgiri Honnapurmath

    2017-01-01

    Full Text Available Background and Objectives: Insulin resistance (IR is frequent in human immunodeficiency virus (HIV infection and may be related to antiretroviral therapy (ART. Increased oxidative stress parameters and carbonyl protein are linked to insulin sensitivity. The present study is aimed to determine IR, its association with oxidative deoxy nucleic acid (DNA damage in HIV-1-infected patients with different ART status. Materials and Methods: In this case–control study, a total 600 subjects were included. We used plasma levels of the oxidized base, 8-hydroxy-2-deoxyguanosine (8-OHdG, as our biomarker of oxidative DNA damage. 8-OHdG was measured with the highly sensitive 8-OHdG check enzyme-linked immunosorbent assay kit. IR was determined using homeostasis model assessment. Results: All subjects were randomly selected and grouped as HIV-negative (control group (n = 300, HIV-positive without ART (n = 100, HIV-positive with ART first line (n = 100, and HIV-positive with ART second line (n = 100. IR and oxidative DNA damage were significantly higher in HIV-positive patients with second-line ART and HIV-positive patients with first-line ART than ART-naive patients. In a linear regression analysis, increased IR was positively associated with the increased DNA damage (odds ratio: 3.052, 95% confidence interval: 2.595–3.509 P < 0.001. Interpretation and Conclusions: In this study, we observed that ART plays a significant role in the development of IR and oxidative DNA damage in HIV-positive patients taking ART. Awareness and knowledge of these biomarkers may prove helpful to clinicians while prescribing ART to HIV/AIDS patients. Larger studies are warranted to determine the exact role of ART in the induction of IR and DNA damage.

  9. Dissociation of DNA damage and mitochondrial injury caused by hydrogen peroxide in SV-40 transformed lung epithelial cells

    Directory of Open Access Journals (Sweden)

    Adcock Ian M

    2002-11-01

    Full Text Available Abstract Background Since lung epithelial cells are constantly being exposed to reactive oxygen intermediates (ROIs, the alveolar surface is a major site of oxidative stress, and each cell type may respond differently to oxidative stress. We compared the extent of oxidative DNA damage with that of mitochondrial injury in lung epithelial cells at the single cell level. Result DNA damage and mitochondrial injury were measured after oxidative stress in the SV-40 transformed lung epithelial cell line challenged with hydrogen peroxide (H2O2. Single cell analysis of DNA damage was determined by assessing the number of 8-oxo-2-deoxyguanosine (8-oxo-dG positive cells, a marker of DNA modification, and the length of a comet tail. Mitochondrial membrane potential, ΔΨm, was determined using JC-1. A 1 h pulse of H2O2 induced small amounts of apoptosis (3%. 8-oxo-dG-positive cells and the length of the comet tail increased within 1 h of exposure to H2O2. The number of cells with reduced ΔΨm increased after the addition of H2O2 in a concentration-dependent manner. In spite of a continual loss of ΔΨm, DNA fragmentation was reduced 2 h after exposure to H2O2. Conclusion The data suggest that SV-40 transformed lung epithelial cells are resistant to oxidative stress, showing that DNA damage can be dissociated from mitochondrial injury.

  10. Urinary 8-hydroxy-deoxyguanosine as a biomarker of oxidative DNA damage in employees of subway system.

    Science.gov (United States)

    Mehrdad, Ramin; Aghdaei, Sara; Pouryaghoub, Gholamreza

    2015-01-01

    Exposure to air pollutants, steel dust or other occupational and environmental hazards as oxidative stress have adverse effects on subway workers' health. Oxidative stress generates an excessive amount of reactive oxygen species (ROS) and Oxygen Free Radicals during their work time in the tunnels. Once DNA is repaired, Urinary 8-hydroxy-deoxyguanosine (8-OHdG) is excreted in the urine. Therefore, urinary level of 8-OHdG can reflect the extent of oxidative DNA damage. The aim of this study was to document the oxidative stress caused by exposure to these hazards by measuring 8-OHdG in workers urine. We collected urine samples of 81 male subway workers after their working shift. The concentration of urinary 8-OHdG was measured by ELISA method. We used linear regression analysis to compare the level of urinary 8-OHdG as a biomarker of oxidative stress between workers in tunnels and other staff. The mean concentration of urinary 8-OHdG for workers in the tunnel was 58.05 (SD=28.83) ng/mg creatinine and for another staff was 54.16 (SD =26.98) ng/mg creatinine.  After adjustment for age, smoking, driving and a second job in a linear regression model, the concentration of 8-OHdG for the exposed group was significantly higher than unexposed group (P=0.038). These findings confirm that the concentration of urinary 8-OHdG for workers who work in tunnels was significantly higher than the other staff. Additional investigations should be performed to understand that which ones of occupational exposures are more important to cause oxidative stress.

  11. The DNA damage response during mitosis.

    Science.gov (United States)

    Heijink, Anne Margriet; Krajewska, Małgorzata; van Vugt, Marcel A T M

    2013-10-01

    Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Close encounters for the first time: Helicase interactions with DNA damage.

    Science.gov (United States)

    Khan, Irfan; Sommers, Joshua A; Brosh, Robert M

    2015-09-01

    DNA helicases are molecular motors that harness the energy of nucleoside triphosphate hydrolysis to unwinding structured DNA molecules that must be resolved during cellular replication, DNA repair, recombination, and transcription. In vivo, DNA helicases are expected to encounter a wide spectrum of covalent DNA modifications to the sugar phosphate backbone or the nitrogenous bases; these modifications can be induced by endogenous biochemical processes or exposure to environmental agents. The frequency of lesion abundance can vary depending on the lesion type. Certain adducts such as oxidative base modifications can be quite numerous, and their effects can be helix-distorting or subtle perturbations to DNA structure. Helicase encounters with specific DNA lesions and more novel forms of DNA damage will be discussed. We will also review the battery of assays that have been used to characterize helicase-catalyzed unwinding of damaged DNA substrates. Characterization of the effects of specific DNA adducts on unwinding by various DNA repair and replication helicases has proven to be insightful for understanding mechanistic and biological aspects of helicase function in cellular DNA metabolism. Published by Elsevier B.V.

  13. The relationship between biomarkers of oxidative DNA damage, polycyclic aromatic hydrocarbon DNA adducts, antioxidant status and genetic susceptibility following exposure to environmental air pollution in humans

    Czech Academy of Sciences Publication Activity Database

    Shing, R.; Šrám, Radim; Binková, Blanka; Kalina, I.; Popov, T. A.; Georgieva, T.; Garte, S.; Taioli, E.; Farmer, P. B.

    2007-01-01

    Roč. 620, - (2007), s. 83-92 ISSN 0027-5107 Grant - others:EU(GB) 2000-00091; EU(GB) G0100873 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK ; R - rámcový projekt EK Keywords : air pollution * PAHs * oxidative DNA damage Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

  14. DNA Damage, Mutagenesis and Cancer

    Directory of Open Access Journals (Sweden)

    Ashis K. Basu

    2018-03-01

    Full Text Available A large number of chemicals and several physical agents, such as UV light and γ-radiation, have been associated with the etiology of human cancer. Generation of DNA damage (also known as DNA adducts or lesions induced by these agents is an important first step in the process of carcinogenesis. Evolutionary processes gave rise to DNA repair tools that are efficient in repairing damaged DNA; yet replication of damaged DNA may take place prior to repair, particularly when they are induced at a high frequency. Damaged DNA replication may lead to gene mutations, which in turn may give rise to altered proteins. Mutations in an oncogene, a tumor-suppressor gene, or a gene that controls the cell cycle can generate a clonal cell population with a distinct advantage in proliferation. Many such events, broadly divided into the stages of initiation, promotion, and progression, which may occur over a long period of time and transpire in the context of chronic exposure to carcinogens, can lead to the induction of human cancer. This is exemplified in the long-term use of tobacco being responsible for an increased risk of lung cancer. This mini-review attempts to summarize this wide area that centers on DNA damage as it relates to the development of human cancer.

  15. Association between age and repair of oxidatively damaged DNA in human peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Løhr, Mille; Jensen, Annie; Eriksen, Louise

    2015-01-01

    damaged DNA in peripheral blood mononuclear cells (PBMCs). We isolated PBMCs from subjects aged 18-83 years, as part of a health survey of the Danish population that focussed on lifestyle factors. The level of DNA repair activity was measured as incisions on potassium bromate-damaged DNA by the comet...... assay. There was an inverse association between age and DNA repair activity with a 0.65% decline in activity per year from age 18 to 83 (95% confidence interval: 0.16-1.14% per year). Univariate regression analysis also indicated inverse associations between DNA repair activity and waist-hip ratio (P...

  16. Damages induced in lambda phage DNA by enzyme-generated triplet acetone

    International Nuclear Information System (INIS)

    Menck, C.F.; Cabral Neto, J.B.; Gomes, R.A.; Faljoni-Alario, A.

    1985-01-01

    Exposure of lambda phage to triplet acetone, generated during the aerobic oxidation of isobutanal by peroxidase, leads to genome lesions. The majority of these lesions are detected as DNA single-strand breaks only in alkaline conditions, so true breaks were not observed. Also, no sites sensitive to UV-endonuclease from Micrococcus luteus were found in DNA from treated phage. The participation of triplet acetone in the generation of such DNA damage is discussed. (Author) [pt

  17. DNA Damage and Base Excision Repair in Mitochondria and Their Role in Aging

    Directory of Open Access Journals (Sweden)

    Ricardo Gredilla

    2011-01-01

    Full Text Available During the last decades, our knowledge about the processes involved in the aging process has exponentially increased. However, further investigation will be still required to globally understand the complexity of aging. Aging is a multifactorial phenomenon characterized by increased susceptibility to cellular loss and functional decline, where mitochondrial DNA mutations and mitochondrial DNA damage response are thought to play important roles. Due to the proximity of mitochondrial DNA to the main sites of mitochondrial-free radical generation, oxidative stress is a major source of mitochondrial DNA mutations. Mitochondrial DNA repair mechanisms, in particular the base excision repair pathway, constitute an important mechanism for maintenance of mitochondrial DNA integrity. The results reviewed here support that mitochondrial DNA damage plays an important role in aging.

  18. Electrochemical behavior of antioxidants: Part 3. Electrochemical studies of caffeic Acid–DNA interaction and DNA/carbon nanotube biosensor for DNA damage and protection

    Directory of Open Access Journals (Sweden)

    Refat Abdel-Hamid

    2016-05-01

    Full Text Available Multi-walled carbon nanotubes-modified glassy carbon electrode biosensor was used for electrochemical studies of caffeic acid–dsDNA interaction in phosphate buffer solution at pH 2.12. Caffeic acid, CAF, shows a well-defined cyclic voltammetric wave. Its anodic peak current decreases and the peak potential shifts positively on the addition of dsDNA. This behavior was ascribed to an interaction of CAF with dsDNA giving CAF–dsDNA complex by intercalative binding mode. The apparent binding constant of CAF–dsDNA complex was determined using amperometric titrations. The oxidative damage caused to DNA was detected using the biosensor. The damage caused by the reactive oxygen species, hydroxyl radical (·−OH generated by the Fenton system on the DNA-biosensor was detected. It was found that CAF has the capability of scavenging the hydroxide radical and protecting the DNA immobilized on the GCE surface.

  19. Oxidized DNA induces an adaptive response in human fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Kostyuk, Svetlana V., E-mail: svet.kostyuk@gmail.com [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Tabakov, Viacheslav J.; Chestkov, Valerij V.; Konkova, Marina S.; Glebova, Kristina V.; Baydakova, Galina V.; Ershova, Elizaveta S.; Izhevskaya, Vera L. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Baranova, Ancha, E-mail: abaranov@gmu.edu [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Center for the Study of Chronic Metabolic Diseases, School of System Biology, George Mason University, Fairfax, VA 22030 (United States); Veiko, Natalia N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2013-07-15

    Highlights: • We describe the effects of gDNAOX on human fibroblasts cultivated in serum withdrawal conditions. • gDNAOX evokes an adaptive response in human fibroblasts. • gDNAOX increases the survival rates in serum starving cell populations. • gDNAOX enhances the survival rates in cell populations irradiated at 1.2 Gy dose. • gDNAOX up-regulates NRF2 and inhibits NF-kappaB-signaling. - Abstract: Cell-free DNA (cfDNA) released from dying cells contains a substantial proportion of oxidized nucleotides, thus, forming cfDNA{sup OX}. The levels of cfDNA{sup OX} are increased in the serum of patients with chronic diseases. Oxidation of DNA turns it into a stress signal. The samples of genomic DNA (gDNA) oxidized by H{sub 2}O{sub 2}in vitro (gDNA{sup OX}) induce effects similar to that of DNA released from damaged cells. Here we describe the effects of gDNA{sup OX} on human fibroblasts cultivated in the stressful conditions of serum withdrawal. In these cells, gDNA{sup OX} evokes an adaptive response that leads to an increase in the rates of survival in serum starving cell populations as well as in populations irradiated at the dose of 1.2 Gy. These effects are not seen in control populations of fibroblasts treated with non-modified gDNA. In particular, the exposure to gDNA{sup OX} leads to a decrease in the expression of the proliferation marker Ki-67 and an increase in levels of PSNA, a decrease in the proportion of subG1- and G2/M cells, a decrease in proportion of cells with double strand breaks (DSBs). Both gDNA{sup OX} and gDNA suppress the expression of DNA sensors TLR9 and AIM2 and up-regulate nuclear factor-erythroid 2 p45-related factor 2 (NRF2), while only gDNA{sup OX} inhibits NF-κB signaling. gDNA{sup OX} is a model for oxidized cfDNA{sup OX} that is released from the dying tumor cells and being carried to the distant organs. The systemic effects of oxidized DNA have to be taken into account when treating tumors. In particular, the damaged DNA

  20. DNA damage in plant herbarium tissue.

    Science.gov (United States)

    Staats, Martijn; Cuenca, Argelia; Richardson, James E; Vrielink-van Ginkel, Ria; Petersen, Gitte; Seberg, Ole; Bakker, Freek T

    2011-01-01

    Dried plant herbarium specimens are potentially a valuable source of DNA. Efforts to obtain genetic information from this source are often hindered by an inability to obtain amplifiable DNA as herbarium DNA is typically highly degraded. DNA post-mortem damage may not only reduce the number of amplifiable template molecules, but may also lead to the generation of erroneous sequence information. A qualitative and quantitative assessment of DNA post-mortem damage is essential to determine the accuracy of molecular data from herbarium specimens. In this study we present an assessment of DNA damage as miscoding lesions in herbarium specimens using 454-sequencing of amplicons derived from plastid, mitochondrial, and nuclear DNA. In addition, we assess DNA degradation as a result of strand breaks and other types of polymerase non-bypassable damage by quantitative real-time PCR. Comparing four pairs of fresh and herbarium specimens of the same individuals we quantitatively assess post-mortem DNA damage, directly after specimen preparation, as well as after long-term herbarium storage. After specimen preparation we estimate the proportion of gene copy numbers of plastid, mitochondrial, and nuclear DNA to be 2.4-3.8% of fresh control DNA and 1.0-1.3% after long-term herbarium storage, indicating that nearly all DNA damage occurs on specimen preparation. In addition, there is no evidence of preferential degradation of organelle versus nuclear genomes. Increased levels of C→T/G→A transitions were observed in old herbarium plastid DNA, representing 21.8% of observed miscoding lesions. We interpret this type of post-mortem DNA damage-derived modification to have arisen from the hydrolytic deamination of cytosine during long-term herbarium storage. Our results suggest that reliable sequence data can be obtained from herbarium specimens.

  1. JNK Phosphorylates SIRT6 to Stimulate DNA Double-Strand Break Repair in Response to Oxidative Stress by Recruiting PARP1 to DNA Breaks

    Directory of Open Access Journals (Sweden)

    Michael Van Meter

    2016-09-01

    Full Text Available The accumulation of damage caused by oxidative stress has been linked to aging and to the etiology of numerous age-related diseases. The longevity gene, sirtuin 6 (SIRT6, promotes genome stability by facilitating DNA repair, especially under oxidative stress conditions. Here we uncover the mechanism by which SIRT6 is activated by oxidative stress to promote DNA double-strand break (DSB repair. We show that the stress-activated protein kinase, c-Jun N-terminal kinase (JNK, phosphorylates SIRT6 on serine 10 in response to oxidative stress. This post-translational modification facilitates the mobilization of SIRT6 to DNA damage sites and is required for efficient recruitment of poly (ADP-ribose polymerase 1 (PARP1 to DNA break sites and for efficient repair of DSBs. Our results demonstrate a post-translational mechanism regulating SIRT6, and they provide the link between oxidative stress signaling and DNA repair pathways that may be critical for hormetic response and longevity assurance.

  2. Arsenic transformation predisposes human skin keratinocytes to UV-induced DNA damage yet enhances their survival apparently by diminishing oxidant response

    International Nuclear Information System (INIS)

    Sun Yang; Kojima, Chikara; Chignell, Colin; Mason, Ronald; Waalkes, Michael P.

    2011-01-01

    Inorganic arsenic and UV, both human skin carcinogens, may act together as skin co-carcinogens. We find human skin keratinocytes (HaCaT cells) are malignantly transformed by low-level arsenite (100 nM, 30 weeks; termed As-TM cells) and with transformation concurrently undergo full adaptation to arsenic toxicity involving reduced apoptosis and oxidative stress response to high arsenite concentrations. Oxidative DNA damage (ODD) is a possible mechanism in arsenic carcinogenesis and a hallmark of UV-induced skin cancer. In the current work, inorganic arsenite exposure (100 nM) did not induce ODD during the 30 weeks required for malignant transformation. Although acute UV-treatment (UVA, 25 J/cm 2 ) increased ODD in passage-matched control cells, once transformed by arsenic to As-TM cells, acute UV actually further increased ODD (> 50%). Despite enhanced ODD, As-TM cells were resistant to UV-induced apoptosis. The response of apoptotic factors and oxidative stress genes was strongly mitigated in As-TM cells after UV exposure including increased Bcl2/Bax ratio and reduced Caspase-3, Nrf2, and Keap1 expression. Several Nrf2-related genes (HO-1, GCLs, SOD) showed diminished responses in As-TM cells after UV exposure consistent with reduced oxidant stress response. UV-exposed As-TM cells showed increased expression of cyclin D1 (proliferation gene) and decreased p16 (tumor suppressor). UV exposure enhanced the malignant phenotype of As-TM cells. Thus, the co-carcinogenicity between UV and arsenic in skin cancer might involve adaptation to chronic arsenic exposure generally mitigating the oxidative stress response, allowing apoptotic by-pass after UV and enhanced cell survival even in the face of increased UV-induced oxidative stress and increased ODD. - Highlights: → Arsenic transformation adapted to UV-induced apoptosis. → Arsenic transformation diminished oxidant response. → Arsenic transformation enhanced UV-induced DNA damage.

  3. DNA damage response in a radiation resistant bacterium Deinococcus radiodurans: a paradigm shift

    International Nuclear Information System (INIS)

    Misra, H.S.

    2015-01-01

    Deinococcusradiodurans is best known for its extraordinary resistance to gamma radiation with its D 10 12kGy, and several other DNA damaging agents including desiccation to less than 5% humidity and chemical xenotoxicants. An efficient DNA double strand break (DSB) repair and its ability to protect biomolecules from oxidative damage are a few mechanisms attributed to these phenotypes in this bacterium. Although it regulates its proteome and transcriptome in response to DNA damage for its growth and survival, it lacks LexA mediated classical SOS response mechanism. Since LexA mediated damages response mechanism is highly and perhaps only, characterized DNA damage response processes in prokaryotes, this bacterium keeps us guessing how it responds to extreme doses of DNA damage. Interestingly, this bacterium encodes a large number of eukaryotic type serine threonine/tyrosine protein kinases (eST/YPK), phosphatases and response regulators and roles of eST/YPKs in cellular response to DNA damage and cell cycle regulations are well established in eukaryotes. Here, we characterized an antioxidant and DNA damage inducible eST/YPK (RqkA) and established its role in extraordinary radioresistance and DSB repair in this bacterium. We identified native phosphoprotein substrates for this kinase and demonstrated the involvement of some of these proteins phosphorylation in the regulation of DSB repair and growth under radiation stress. Findings suggesting the possible existence of eST/YPK mediated DNA damage response mechanism as an alternate to classical SOS response in this prokaryote would be discussed. (author)

  4. Fertilization capacity with rainbow trout DNA-damaged sperm and embryo developmental success.

    Science.gov (United States)

    Pérez-Cerezales, S; Martínez-Páramo, S; Beirão, J; Herráez, M P

    2010-06-01

    Mammalian spermatozoa undergo a strong selection process along the female tract to guarantee fertilization by good quality cells, but risks of fertilization with DNA-damaged spermatozoa have been reported. In contrast, most external fertilizers such as fish seem to have weaker selection procedures. This fact, together with their high prolificacy and external embryo development, indicates that fish could be useful for the study of the effects of sperm DNA damage on embryo development. We cryopreserved sperm from rainbow trout using egg yolk and low-density lipoprotein as additives to promote different rates of DNA damage. DNA fragmentation and oxidization were analyzed using comet assay with and without digestion with restriction enzymes, and fertilization trials were performed. Some embryo batches were treated with 3-aminobenzamide (3AB) to inhibit DNA repair by the poly (ADP-ribose) polymerase, which is an enzyme of the base excision repair pathway. Results showed that all the spermatozoa cryopreserved with egg yolk carried more than 10% fragmented DNA, maintaining fertilization rates of 61.1+/-2.3 but a high rate of abortions, especially during gastrulation, and only 14.5+/-4.4 hatching success. Furthermore, after 3AB treatment, hatching dropped to 3.2+/-2.2, showing that at least 10% DNA fragmentation was repaired. We conclude that trout sperm maintains its ability to fertilize in spite of having DNA damage, but that embryo survival is affected. Damage is partially repaired by the oocyte during the first cleavage. Important advantages of using rainbow trout for the study of processes related to DNA damage and repair during development have been reported.

  5. Piper nigrum ethanolic extract rich in piperamides causes ROS overproduction, oxidative damage in DNA leading to cell cycle arrest and apoptosis in cancer cells.

    Science.gov (United States)

    de Souza Grinevicius, Valdelúcia Maria Alves; Kviecinski, Maicon Roberto; Santos Mota, Nádia Sandrini Ramos; Ourique, Fabiana; Porfirio Will Castro, Luiza Sheyla Evenni; Andreguetti, Rafaela Rafognato; Gomes Correia, João Francisco; Filho, Danilo Wilhem; Pich, Claus Tröger; Pedrosa, Rozangela Curi

    2016-08-02

    Ayurvedic and Chinese traditional medicine and tribal people use herbal preparations containing Piper nigrum fruits for the treatment of many health disorders like inflammation, fever, asthma and cancer. In Brazil, traditional maroon culture associates the spice Piper nigrum to health recovery and inflammation attenuation. The aim of the current work was to evaluate the relationship between reactive oxygen species (ROS) overproduction, DNA fragmentation, cell cycle arrest and apoptosis induced by Piper nigrum ethanolic extract and its antitumor activity. The plant was macerated in ethanol. Extract constitution was assessed by TLC, UV-vis and ESI-IT-MS/MS spectrometry. The cytotoxicity, proliferation and intracellular ROS generation was evaluated in MCF-7 cells. DNA damage effects were evaluated through intercalation into CT-DNA, plasmid DNA cleavage and oxidative damage in CT-DNA. Tumor growth inhibition, survival time increase, apoptosis, cell cycle arrest and oxidative stress were assessed in Ehrlich ascites carcinoma-bearing mice. Extraction yielded 64mg/g (36% piperine and 4.2% piperyline). Treatments caused DNA damage and reduced cell viability (EC50=27.1±2.0 and 80.5±6.6µg/ml in MCF-7 and HT-29 cells, respectively), inhibiting cell proliferation by 57% and increased ROS generation in MCF-7 cells (65%). Ehrlich carcinoma was inhibited by the extract, which caused reduction of tumor growth (60%), elevated survival time (76%), cell cycle arrest and induced apoptosis. The treatment with extract increased Bax and p53 and inhibited Bcl-xL and cyclin A expression. It also induced an oxidative stress in vivo verified as enhanced lipid peroxidation and carbonyl proteins content and increased activities of glutathione reductase, superoxide dismutase and catalase. GSH concentration was decreased in tumor tissue from mice. The ethanolic extract has cytotoxic and antiproliferative effect on MCF-7 cells and antitumor effect in vivo probably due to ROS overproduction

  6. DNA damage and repair in plants

    International Nuclear Information System (INIS)

    Britt, A.B.

    1996-01-01

    The biological impact of any DNA damaging agent is a combined function of the chemical nature of the induced lesions and the efficiency and accuracy of their repair. Although much has been learned frommicrobes and mammals about both the repair of DNA damage and the biological effects of the persistence of these lesions, much remains to be learned about the mechanism and tissue-specificity of repair in plants. This review focuses on recent work on the induction and repair of DNA damage in higher plants, with special emphasis on UV-induced DNA damage products. (author)

  7. Hypoxia and oxidation levels of DNA and lipids in humans and animal experimental models

    DEFF Research Database (Denmark)

    Møller, Peter; Risom, Lotte; Lundby, Carsten

    2008-01-01

    The objective of this review was to evaluate the association between hypoxia and oxidative damage to DNA and lipids. Evaluation criteria encompassed specificity and validation status of the biomarkers, study design, strength of the association, dose-response relationship, biological plausibility......, analogous exposures, and effect modification by intervention. The collective interpretation indicates persuasive evidence from the studies in humans for an association between hypoxia and elevated levels of oxidative damage to DNA and lipids. The levels of oxidatively generated DNA lesions and lipid...... in subjects at high altitude. Most of the animal experimental models should be interpreted with caution because the assays for assessment of lipid peroxidation products have suboptimal validity....

  8. Immunoassay of DNA damage

    International Nuclear Information System (INIS)

    Gasparro, F.P.; Santella, R.M.

    1988-01-01

    The direct photomodification of DNA by ultraviolet light or the photo-induced addition of exogenous compounds to DNA components results in alterations of DNA structure ranging from subtle to profound. There are two consequences of these conformational changes. First, cells in which the DNA has been damaged are capable of executing repair steps. Second, the DNA which is usually of very low immunogenicity now becomes highly antigenic. This latter property has allowed the production of a series of monoclonal antibodies that recognize photo-induced DNA damage. Monoclonal antibodies have been generated that recognize the 4',5'-monoadduct and the crosslink of 8-methoxypsoralen in DNA. In addition, another antibody has been prepared which recognizes the furan-side monoadduct of 6,4,4'-trimethylangelicin in DNA. These monoclonal antibodies have been characterized as to sensitivity and specificity using non-competitive and competitive enzyme-linked-immunosorbent assays (ELISA). (author)

  9. Immunoassay of DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Gasparro, F P; Santella, R M

    1988-09-01

    The direct photomodification of DNA by ultraviolet light or the photo-induced addition of exogenous compounds to DNA components results in alterations of DNA structure ranging from subtle to profound. There are two consequences of these conformational changes. First, cells in which the DNA has been damaged are capable of executing repair steps. Second, the DNA which is usually of very low immunogenicity now becomes highly antigenic. This latter property has allowed the production of a series of monoclonal antibodies that recognize photo-induced DNA damage. Monoclonal antibodies have been generated that recognize the 4',5'-monoadduct and the crosslink of 8-methoxypsoralen in DNA. In addition, another antibody has been prepared which recognizes the furan-side monoadduct of 6,4,4'-trimethylangelicin in DNA. These monoclonal antibodies have been characterized as to sensitivity and specificity using non-competitive and competitive enzyme-linked-immunosorbent assays (ELISA).

  10. Oxidative stress/damage induces multimerization and interaction of Fanconi anemia proteins.

    Science.gov (United States)

    Park, Su-Jung; Ciccone, Samantha L M; Beck, Brian D; Hwang, Byounghoon; Freie, Brian; Clapp, D Wade; Lee, Suk-Hee

    2004-07-16

    Fanconi anemia (FANC) is a heterogeneous genetic disorder characterized by a hypersensitivity to DNA-damaging agents, chromosomal instability, and defective DNA repair. Eight FANC genes have been identified so far, and five of them (FANCA, -C, -E, -F, and -G) assemble in a multinuclear complex and function at least in part in a complex to activate FANCD2 by monoubiquitination. Here we show that FANCA and FANCG are redox-sensitive proteins that are multimerized and/or form a nuclear complex in response to oxidative stress/damage. Both FANCA and FANCG proteins exist as monomers under non-oxidizing conditions, whereas they become multimers following H2O2 treatment. Treatment of cells with oxidizing agent not only triggers the multimeric complex of FANCA and FANCG in vivo but also induces the interaction between FANCA and FANCG. N-Ethylmaleimide treatment abolishes multimerization and interaction of FANCA and FANCG in vitro. Taken together, our results lead us to conclude that FANCA and FANCG uniquely respond to oxidative damage by forming complex(es) via intermolecular disulfide linkage(s), which may be crucial in forming such complexes and in determining their function.

  11. Molecular epidemiology studies of carcinogenic environmental pollutants. Effects of polycyclic aromatic hydrocarbons (PAHs) in environmental pollution on exogenous and oxidative DNA damage.

    Science.gov (United States)

    Farmer, Peter B; Singh, Rajinder; Kaur, Balvinder; Sram, Radim J; Binkova, Blanka; Kalina, Ivan; Popov, Todor A; Garte, Seymour; Taioli, Emanuela; Gabelova, Alena; Cebulska-Wasilewska, Antonina

    2003-11-01

    Exposure to high levels of environmental air pollution is known to be associated with an increased carcinogenic risk. The individual contribution to this risk derived from specific carcinogenic chemicals within the complex mixture of air pollution is less certain, but may be explored by the use of molecular epidemiological techniques. Measurements of biomarkers of exposure, of effect and of susceptibility provide information of potential benefit for epidemiological and cancer risk assessment. The application of such techniques has been mostly concerned in the past with the carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) that are associated with particulate matter in air pollution, and has showed clear evidence of genotoxic effects, such as DNA adducts, chromosome aberrations (CA) and ras oncogene overexpression, in environmentally exposed Czech and Polish populations. We are currently extending these studies by an investigation of populations exposed to environmental pollution in three European countries, Czech Republic, Slovak Republic and Bulgaria. This pays particular attention to PAHs, but also investigates the extent of radically induced (oxidative) DNA damage in the exposed populations. Policemen, bus drivers and controls, who carried personal monitors to determine their exposures to PAHs have been studied, and blood and urine were collected. Antioxidant and dietary status were assessed in these populations. Stationary monitors were also used for ambient air monitoring. Amongst the parameters studied in the biological samples were: (a) exposure biomarkers, such as PAH adducts with DNA, p53 and p21(WAF1) protein levels, (b) oxidative DNA damage, (c) the biological effect of the exposure by measurement of chromosome damage by fluorescence in situ hybridisation (FISH) or conventional methods, and (d) polymorphisms in carcinogen metabolising and DNA repair enzymes. Repair ability was also measured by the Comet assay. In vitro systems are being evaluated to

  12. Base Flip in DNA Studied by Molecular Dynamics Simulationsof Differently-Oxidized Forms of Methyl-Cytosine

    Directory of Open Access Journals (Sweden)

    Mahdi Bagherpoor Helabad

    2014-07-01

    Full Text Available Distortions in the DNA sequence, such as damage or mispairs, are specifically recognized and processed by DNA repair enzymes. Many repair proteins and, in particular, glycosylases flip the target base out of the DNA helix into the enzyme’s active site. Our molecular dynamics simulations of DNA with intact and damaged (oxidized methyl-cytosine show that the probability of being flipped is similar for damaged and intact methyl-cytosine. However, the accessibility of the different 5-methyl groups allows direct discrimination of the oxidized forms. Hydrogen-bonded patterns that vary between methyl-cytosine forms carrying a carbonyl oxygen atom are likely to be detected by the repair enzymes and may thus help target site recognition.

  13. Mechanisms of mutagenesis: DNA replication in the presence of DNA damage.

    Science.gov (United States)

    Liu, Binyan; Xue, Qizhen; Tang, Yong; Cao, Jia; Guengerich, F Peter; Zhang, Huidong

    2016-01-01

    Environmental mutagens cause DNA damage that disturbs replication and produces mutations, leading to cancer and other diseases. We discuss mechanisms of mutagenesis resulting from DNA damage, from the level of DNA replication by a single polymerase to the complex DNA replisome of some typical model organisms (including bacteriophage T7, T4, Sulfolobus solfataricus, Escherichia coli, yeast and human). For a single DNA polymerase, DNA damage can affect replication in three major ways: reducing replication fidelity, causing frameshift mutations, and blocking replication. For the DNA replisome, protein interactions and the functions of accessory proteins can yield rather different results even with a single DNA polymerase. The mechanism of mutation during replication performed by the DNA replisome is a long-standing question. Using new methods and techniques, the replisomes of certain organisms and human cell extracts can now be investigated with regard to the bypass of DNA damage. In this review, we consider the molecular mechanism of mutagenesis resulting from DNA damage in replication at the levels of single DNA polymerases and complex DNA replisomes, including translesion DNA synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Resveratrol induces membrane and DNA disruption via pro-oxidant activity against Salmonella typhimurium.

    Science.gov (United States)

    Lee, Wonjong; Lee, Dong Gun

    2017-07-22

    Resveratrol is a flavonoid found in various plants including grapes, which has been reported to be active against various pathogenic bacteria. However, antibacterial effects and mechanisms via pro-oxidant property of resveratrol remain unknown and speculative. This research investigated antibacterial mechanism of resveratrol against a food-borne human pathogen Salmonella typhimurium, and confirmed the cell death associated oxidative damage. Resveratrol increased outer membrane permeability and membrane depolarization. It also was observed DNA injury responses such as DNA fragmentation, increasing DNA contents and cell division inhibition. Intracellular ROS accumulation, GSH depletion and significant increased malondialdehyde levels were confirmed, which indicated pro-oxidant activity of resveratrol and oxidative stress. Furthermore, the observed lethal damages were reduced by antioxidant N-acetylcysteine treatment supported the view that resveratrol-induced oxidative stress stimulated S. typhimurium cell death. In conclusion, this study expands understanding on role of pro-oxidant property and insight into previously unrecognized oxygen-dependent anti-Salmonella mechanism on resveratrol. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Pregnancy induces transcriptional activation of the peripheral innate immune system and increases oxidative DNA damage among healthy third trimester pregnant women.

    Directory of Open Access Journals (Sweden)

    Xinyin Jiang

    Full Text Available BACKGROUND: Pregnancy induces physiological adaptations that may involve, or contribute to, alterations in the genomic landscape. Pregnancy also increases the nutritional demand for choline, an essential nutrient that can modulate epigenomic and transcriptomic readouts secondary to its role as a methyl donor. Nevertheless, the interplay between human pregnancy, choline and the human genome is largely unexplored. METHODOLOGY/PRINCIPAL FINDINGS: As part of a controlled feeding study, we assessed the influence of pregnancy and choline intake on maternal genomic markers. Healthy third trimester pregnant (n = 26, wk 26-29 gestation and nonpregnant (n = 21 women were randomized to choline intakes of 480 mg/day, approximating the Adequate Intake level, or 930 mg/day for 12-weeks. Blood leukocytes were acquired at study week 0 and study week 12 for microarray, DNA damage and global DNA/histone methylation measurements. A main effect of pregnancy that was independent of choline intake was detected on several of the maternal leukocyte genomic markers. Compared to nonpregnant women, third trimester pregnant women exhibited higher (P<0.05 transcript abundance of defense response genes associated with the innate immune system including pattern recognition molecules, neutrophil granule proteins and oxidases, complement proteins, cytokines and chemokines. Pregnant women also exhibited higher (P<0.001 levels of DNA damage in blood leukocytes, a genomic marker of oxidative stress. No effect of choline intake was detected on the maternal leukocyte genomic markers with the exception of histone 3 lysine 4 di-methylation which was lower among pregnant women in the 930 versus 480 mg/d choline intake group. CONCLUSIONS: Pregnancy induces transcriptional activation of the peripheral innate immune system and increases oxidative DNA damage among healthy third trimester pregnant women.

  16. Ultraviolet radiation-mediated damage to cellular DNA

    International Nuclear Information System (INIS)

    Cadet, Jean; Sage, Evelyne; Douki, Thierry

    2005-01-01

    Emphasis is placed in this review article on recent aspects of the photochemistry of cellular DNA in which both the UVB and UVA components of solar radiation are implicated individually or synergistically. Interestingly, further mechanistic insights into the UV-induced formation of DNA photoproducts were gained from the application of new accurate and sensitive chromatographic and enzymic assays aimed at measuring base damage. Thus, each of the twelve possible dimeric photoproducts that are produced at the four main bipyrimidine sites can now be singled out as dinucleoside monophosphates that are enzymatically released from UV-irradiated DNA. This was achieved using a recently developed high-performance liquid chromatography-tandem mass spectrometry assay (HPLC-MS/MS) assay after DNA extraction and appropriate enzymic digestion. Interestingly, a similar photoproduct distribution pattern is observed in both isolated and cellular DNA upon exposure to low doses of either UVC or UVB radiation. This applies more specifically to the DNA of rodent and human cells, the cis-syn cyclobutadithymine being predominant over the two other main photolesions, namely thymine-cytosine pyrimidine (6-4) pyrimidone adduct and the related cyclobutyl dimer. UVA-irradiation was found to generate cyclobutane dimers at TT and to a lower extent at TC sites as a likely result of energy transfer mechanism involving still unknown photoexcited chromophore(s). Oxidative damage to DNA is also induced although less efficiently by UVA-mediated photosensitization processes that mostly involved 1 O 2 together with a smaller contribution of hydroxyl radical-mediated reactions through initially generated superoxide radicals

  17. Environmental exposure to human carcinogens in teenagers and the association with DNA damage

    International Nuclear Information System (INIS)

    Franken, Carmen; Koppen, Gudrun; Lambrechts, Nathalie; Govarts, Eva; Bruckers, Liesbeth; Den Hond, Elly; Loots, Ilse; Nelen, Vera; Sioen, Isabelle; Nawrot, Tim S.; Baeyens, Willy; Van Larebeke, Nicolas; Boonen, Francis; Ooms, Daniëlla; Wevers, Mai; Jacobs, Griet; Covaci, Adrian; Schettgen, Thomas; Schoeters, Greet

    2017-01-01

    Background: We investigated whether human environmental exposure to chemicals that are labeled as (potential) carcinogens leads to increased (oxidative) damage to DNA in adolescents. Material and methods: Six hundred 14–15-year-old youngsters were recruited all over Flanders (Belgium) and in two areas with important industrial activities. DNA damage was assessed by alkaline and formamidopyrimidine DNA glycosylase (Fpg) modified comet assays in peripheral blood cells and analysis of urinary 8-hydroxydeoxyguanosine (8-OHdG) levels. Personal exposure to potentially carcinogenic compounds was measured in urine, namely: chromium, cadmium, nickel, 1-hydroxypyrene as a proxy for exposure to other carcinogenic polycyclic aromatic hydrocarbons (PAHs), t,t-muconic acid as a metabolite of benzene, 2,5-dichlorophenol (2,5-DCP), organophosphate pesticide metabolites, and di(2-ethylhexyl) phthalate (DEHP) metabolites. In blood, arsenic, polychlorinated biphenyl (PCB) congeners 118 and 156, hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) and perfluorooctanoic acid (PFOA) were analyzed. Levels of methylmercury (MeHg) were measured in hair. Multiple linear regression models were used to establish exposure-response relationships. Results: Biomarkers of exposure to PAHs and urinary chromium were associated with higher levels of both 8-OHdG in urine and DNA damage detected by the alkaline comet assay. Concentrations of 8-OHdG in urine increased in relation with increasing concentrations of urinary t,t-muconic acid, cadmium, nickel, 2,5-DCP, and DEHP metabolites. Increased concentrations of PFOA in blood were associated with higher levels of DNA damage measured by the alkaline comet assay, whereas DDT was associated in the same direction with the Fpg-modified comet assay. Inverse associations were observed between blood arsenic, hair MeHg, PCB 156 and HCB, and urinary 8-OHdG. The latter exposure biomarkers were also associated with higher fish intake. Urinary nickel

  18. Environmental exposure to human carcinogens in teenagers and the association with DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Franken, Carmen, E-mail: carmen.franken@vito.be [Flemish Institute for Technological Research (VITO), Mol (Belgium); Department of Biomedical Sciences, University of Antwerp, Antwerp (Belgium); Koppen, Gudrun; Lambrechts, Nathalie; Govarts, Eva [Flemish Institute for Technological Research (VITO), Mol (Belgium); Bruckers, Liesbeth [Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Hasselt (Belgium); Den Hond, Elly [Flemish Institute for Technological Research (VITO), Mol (Belgium); Loots, Ilse [Political and Social Sciences, University of Antwerp, Antwerp (Belgium); Nelen, Vera [Provincial Institute for Hygiene, Antwerp (Belgium); Sioen, Isabelle [Department of Public Health, Ghent University, Ghent (Belgium); Department of Food Safety and Food Quality, Ghent University, Ghent (Belgium); Nawrot, Tim S. [Centre for Environmental Sciences, Hasselt University, Diepenbeek (Belgium); Department of Public Health & Primary Care, Leuven University, Leuven (Belgium); Baeyens, Willy [Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Brussels (Belgium); Van Larebeke, Nicolas [Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Brussels (Belgium); Department of Radiotherapy and Experimental Cancerology, Ghent University, Ghent (Belgium); Boonen, Francis; Ooms, Daniëlla; Wevers, Mai; Jacobs, Griet [Flemish Institute for Technological Research (VITO), Mol (Belgium); Covaci, Adrian [Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp (Belgium); Schettgen, Thomas [Department of Occupational and Social Medicine, RWTH Aachen University, Aachen (Germany); Schoeters, Greet [Flemish Institute for Technological Research (VITO), Mol (Belgium); Department of Biomedical Sciences, University of Antwerp, Antwerp (Belgium); University of Southern Denmark, Institute of Public Health, Department of Environmental Medicine, Odense (Denmark)

    2017-01-15

    Background: We investigated whether human environmental exposure to chemicals that are labeled as (potential) carcinogens leads to increased (oxidative) damage to DNA in adolescents. Material and methods: Six hundred 14–15-year-old youngsters were recruited all over Flanders (Belgium) and in two areas with important industrial activities. DNA damage was assessed by alkaline and formamidopyrimidine DNA glycosylase (Fpg) modified comet assays in peripheral blood cells and analysis of urinary 8-hydroxydeoxyguanosine (8-OHdG) levels. Personal exposure to potentially carcinogenic compounds was measured in urine, namely: chromium, cadmium, nickel, 1-hydroxypyrene as a proxy for exposure to other carcinogenic polycyclic aromatic hydrocarbons (PAHs), t,t-muconic acid as a metabolite of benzene, 2,5-dichlorophenol (2,5-DCP), organophosphate pesticide metabolites, and di(2-ethylhexyl) phthalate (DEHP) metabolites. In blood, arsenic, polychlorinated biphenyl (PCB) congeners 118 and 156, hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) and perfluorooctanoic acid (PFOA) were analyzed. Levels of methylmercury (MeHg) were measured in hair. Multiple linear regression models were used to establish exposure-response relationships. Results: Biomarkers of exposure to PAHs and urinary chromium were associated with higher levels of both 8-OHdG in urine and DNA damage detected by the alkaline comet assay. Concentrations of 8-OHdG in urine increased in relation with increasing concentrations of urinary t,t-muconic acid, cadmium, nickel, 2,5-DCP, and DEHP metabolites. Increased concentrations of PFOA in blood were associated with higher levels of DNA damage measured by the alkaline comet assay, whereas DDT was associated in the same direction with the Fpg-modified comet assay. Inverse associations were observed between blood arsenic, hair MeHg, PCB 156 and HCB, and urinary 8-OHdG. The latter exposure biomarkers were also associated with higher fish intake. Urinary nickel

  19. Microfabricated electrochemical sensor for the detection of radiation-induced DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Rivas, G.; Ozsoz, M.; Grant, D.H.; Cai, X.; Parrado, C. [New Mexico State Univ., Las Cruces, NM (United States)

    1997-04-01

    An electrochemical biosensor protocol for the detection of radiation-induced DNA damage is described. The procedure employs a dsDNA-coated screen-printed electrode and relies on changes in the guanine-DNA oxidation signal upon exposure to ultraviolet radiation. The decreased signal is ascribed primarily to conformational changes in the DNA and to the photoconversion of the guanine-DNA moiety to a nonelectroactive monomeric base product. Factors influencing the response of these microfabricated DNA sensors, such as irradiation time, wavelength, and distance, are explored, and future prospects are discussed. Similar results are given for the use of bare strip electrodes in connection with irradiated DNA solutions. 8 refs., 4 figs.

  20. One-electron oxidation of DNA: mechanism and consequences.

    Science.gov (United States)

    Schuster, Gary B

    2009-01-01

    All living organisms store the information necessary to maintain life in their DNA. Any process that damages DNA and causes loss or corruption of that information threatens the viability of the organism. One-electron oxidation is such a process. Loss of an electron from DNA generates a radical cation that is located primarily on its nucleobases. The radical cation migrates reversibly through duplex DNA by hopping until it is eventually trapped in an irreversible chemical reaction. The particular sequence of nucleobases in a DNA oligomer determines both the efficiency of hopping and the specific location and nature of the damaging chemical reaction. In its normal aqueous solutions, DNA is a polyanion because of the negative charge carried by its phosphate groups. Counter ions (typically Na(+)) to the phosphate groups play an important role in facilitating both the migration of the radical cation and in its eventual reaction with H(2)O. Irreversible reaction of a radical cation with H(2)O in duplex DNA occurs preferentially at the most reactive site. In normal DNA that is comprised of the four common DNA nucleobases, reaction occurs most commonly at a guanine and results in its conversion primarily to 8-oxo-7,8-dihydroguanine (8-OxoG). Both electronic and steric effects control the outcome of this process. If the DNA oligomer does not contain a suitable guanine, then reaction of the radical cation occurs at the thymine of a TT step primarily by a tandem process. The general outcomes revealed in the one-electron oxidation of DNA oligomers in solution appear to be generally valid also for more complex DNA structures and for the cellular DNA of living organisms.

  1. Potentiometric sensing of nuclease activities and oxidative damage of single-stranded DNA using a polycation-sensitive membrane electrode.

    Science.gov (United States)

    Ding, Jiawang; Qin, Wei

    2013-09-15

    A simple, general and label-free potentiometric method to measure nuclease activities and oxidative DNA damage in a homogeneous solution using a polycation-sensitive membrane electrode is reported. Protamine, a linear polyionic species, is used as an indicator to report the cleavage of DNA by nucleases such as restriction and nonspecific nucleases, and the damage of DNA induced by hydroxyl radicals. Measurements can be done with a titration mode or a direct detection mode. For the potentiometric titration mode, the enzymatic cleavage dramatically affects the electrostatical interaction between DNA and protamine and thus shifts the response curve for the potentiometric titration of the DNA with protamine. Under the optimized conditions, the enzyme activities can be sensed potentiometrically with detection limits of 2.7×10(-4)U/µL for S1 nuclease, and of 3.9×10(-4)U/µL for DNase I. For the direct detection mode, a biocomplex between protamine and DNA is used as a substrate. The nuclease of interest cleaves the DNA from the protamine/DNA complex into smaller fragments, so that free protamine is generated and can be detected potentiometrically via the polycation-sensitive membrane electrode. Using a direct measurement, the nuclease activities could be rapidly detected with detection limits of 3.2×10(-4)U/µL for S1 nuclease, and of 4.5×10(-4)U/µL for DNase I. Moreover, the proposed potentiometric assays demonstrate the potential applications in the detection of hydroxyl radicals. It is anticipated that the present potentiometric strategy will provide a promising platform for high-throughput screening of nucleases, reactive oxygen species and the drugs with potential inhibition abilities. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Ex-vivo and in vitro protective effects of kolaviron against oxygen-derived radical-induced DNA damage and oxidative stress in human lymphocytes and rat liver cells

    DEFF Research Database (Denmark)

    Farombi, E.O.; Moller, P.; Dragsted, L.O.

    2004-01-01

    at concentrations between 30-90 mumol/L and decreased H2O2-induced DNA strand breaks and oxidized bases. Neither alpha-tocopherol nor curcumin decreased H2O2-induced DNA damage in this assay. In lymphocytes incubated with Fe3+ /GSH, Fe3+ was reduced to Fe2+ by GSH initiating a free radical generating reaction which...

  3. Mechanism of metformin action in MCF-7 and MDA-MB-231 human breast cancer cells involves oxidative stress generation, DNA damage, and transforming growth factor β1 induction.

    Science.gov (United States)

    Marinello, Poliana Camila; da Silva, Thamara Nishida Xavier; Panis, Carolina; Neves, Amanda Fouto; Machado, Kaliana Larissa; Borges, Fernando Henrique; Guarnier, Flávia Alessandra; Bernardes, Sara Santos; de-Freitas-Junior, Júlio Cesar Madureira; Morgado-Díaz, José Andrés; Luiz, Rodrigo Cabral; Cecchini, Rubens; Cecchini, Alessandra Lourenço

    2016-04-01

    The participation of oxidative stress in the mechanism of metformin action in breast cancer remains unclear. We investigated the effects of clinical (6 and 30 μM) and experimental concentrations of metformin (1000 and 5000 μM) in MCF-7 and in MDA-MB-231 cells, verifying cytotoxicity, oxidative stress, DNA damage, and intracellular pathways related to cell growth and survival after 24 h of drug exposure. Clinical concentrations of metformin decreased metabolic activity of MCF-7 cells in the MTT assay, which showed increased oxidative stress and DNA damage, although cell death and impairment in the proliferative capacity were observed only at higher concentrations. The reduction in metabolic activity and proliferation in MDA-MB-231 cells was present only at experimental concentrations after 24 h of drug exposition. Oxidative stress and DNA damage were induced in this cell line at experimental concentrations. The drug decreased cytoplasmic extracellular signal-regulated kinases 1 and 2 (ERK1/2) and AKT and increased nuclear p53 and cytoplasmic transforming growth factor β1 (TGF-β1) in both cell lines. These findings suggest that metformin reduces cell survival by increasing reactive oxygen species, which induce DNA damage and apoptosis. A relationship between the increase in TGF-β1 and p53 levels and the decrease in ERK1/2 and AKT was also observed. These findings suggest the mechanism of action of metformin in both breast cancer cell lineages, whereas cell line specific undergoes redox changes in the cells in which proliferation and survival signaling are modified. Taken together, these results highlight the potential clinical utility of metformin as an adjuvant during the treatment of luminal and triple-negative breast cancer.

  4. Hydroxyl radicals (·OH) are associated with titanium dioxide (TiO2) nanoparticle-induced cytotoxicity and oxidative DNA damage in fish cells

    International Nuclear Information System (INIS)

    Reeves, James F.; Davies, Simon J.; Dodd, Nicholas J.F.; Jha, Awadhesh N.

    2008-01-01

    TiO 2 nanoparticles ( 2 nanoparticles on goldfish skin cells (GFSk-S1), either alone or in combination with UVA. Whilst neutral red retention (NRR) assay (a measure of lysosomal membrane integrity) was used to evaluate cell viability, a modified Comet assay using bacterial lesion-specific repair endonucleases (Endo-III, Fpg) was employed to specifically target oxidative DNA damage. Additionally, electron spin resonance (ESR) studies with different spin traps were carried out for qualitative analysis of free radical generation. For cell viability, TiO 2 alone (0.1-1000 μg ml -1 ) had little effect whereas co-exposure with UVA (0.5-2.0 kJ m -2 ) caused a significant dose-dependent decrease which was dependent on both the concentration of TiO 2 and the dose of UVA administered. For the Comet assay, doses of 1, 10 and 100 μg ml -1 in the absence of UVA caused elevated levels of Fpg-sensitive sites, indicating the oxidation of purine DNA bases (i.e. guanine) by TiO 2 . UVA irradiation of TiO 2 -treated cells caused further increases in DNA damage. ESR studies revealed that the observed toxic effects of nanoparticulate TiO 2 were most likely due to hydroxyl radical (·OH) formation

  5. Menadione-Induced DNA Damage Leads to Mitochondrial Dysfunction and Fragmentation During Rosette Formation in Fuchs Endothelial Corneal Dystrophy.

    Science.gov (United States)

    Halilovic, Adna; Schmedt, Thore; Benischke, Anne-Sophie; Hamill, Cecily; Chen, Yuming; Santos, Janine Hertzog; Jurkunas, Ula V

    2016-06-20

    Fuchs endothelial corneal dystrophy (FECD), a leading cause of age-related corneal edema requiring transplantation, is characterized by rosette formation of corneal endothelium with ensuing apoptosis. We sought to determine whether excess of mitochondrial reactive oxygen species leads to chronic accumulation of oxidative DNA damage and mitochondrial dysfunction, instigating cell death. We modeled the pathognomonic rosette formation of postmitotic corneal cells by increasing endogenous cellular oxidative stress with menadione (MN) and performed a temporal analysis of its effect in normal (HCEnC, HCECi) and FECD (FECDi) cells and ex vivo specimens. FECDi and FECD ex vivo specimens exhibited extensive mtDNA and nDNA damage as detected by quantitative PCR. Exposure to MN triggered an increase in mitochondrial superoxide levels and led to mtDNA and nDNA damage, while DNA amplification was restored with NAC pretreatment. Furthermore, MN exposure led to a decrease in ΔΨm and adenosine triphosphate levels in normal cells, while FECDi exhibited mitochondrial dysfunction at baseline. Mitochondrial fragmentation and cytochrome c release were detected in FECD tissue and after MN treatment of HCEnCs. Furthermore, cleavage of caspase-9 and caspase-3 followed MN-induced cytochrome c release in HCEnCs. This study provides the first line of evidence that accumulation of oxidative DNA damage leads to rosette formation, loss of functionally intact mitochondria via fragmentation, and subsequent cell death during postmitotic cell degeneration of ocular tissue. MN induced rosette formation, along with mtDNA and nDNA damage, mitochondrial dysfunction, and fragmentation, leading to activation of the intrinsic apoptosis via caspase cleavage and cytochrome c release. Antioxid. Redox Signal. 24, 1072-1083.

  6. Evaluation of DNA damage and antioxidant system induced by di-n-butyl phthalates exposure in earthworms (Eisenia fetida).

    Science.gov (United States)

    Du, Li; Li, Guangde; Liu, Mingming; Li, Yanqiang; Yin, Suzhen; Zhao, Jie; Zhang, Xinyi

    2015-05-01

    Di-n-butyl phthalates (DBP) are recognized as ubiquitous contaminants in soil and adversely impact the health of organisms. The effect of DBP on the activity of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT), malondialdehyde (MDA) content and DNA damage were used as biomarkers to analyze the relationship between DNA damage and oxidative stress and to evaluate the genotoxic effect of DBP on earthworms (Eisenia fetida). DBP was added to artificial soil in the amounts of 0, 5, 10, 50 and 100mg per kg of soil. Earthworm tissues exposed to each treatment were collected on the 7th, 14th, 21st, and 28th day of the treatment. The results showed that SOD and CAT levels were significantly inhibited in the 100mgkg(-1) treatment group on day 28. MDA content in treatment groups was higher than in the control group throughout the exposure time, suggesting that DBP may lead to oxidative stress in cells. A dose-response relationship existed between DNA damage and total soil DBP levels. The comet assay showed that increasing concentrations of DBP resulted in a gradual increase in the OTM, Comet Tail Length and Tail DNA %. The degree of DNA damage was increased with increasing concentration of DBP. These results suggested that DBP induced serious oxidative damage on earthworms and induced the formation of reactive oxygen species (ROS) in earthworms. The excessive generation of ROS caused damage to vital macromolecules including lipids and DNA. DBP in the soils were responsible for the exerting genotoxic effects on earthworms. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Radiation damage in DNA

    International Nuclear Information System (INIS)

    Lafleur, V.

    1978-01-01

    A number of experiments are described with the purpose to obtain a better insight in the chemical nature and the biological significance of radiation-induced damage in DNA, with some emphasis on the significance of alkali-labile sites. It is shown that not only reactions of OH radicals but also of H radicals introduce breaks and other inactivating damage in single-standed phiX174 DNA. It is found that phosphate buffer is very suitable for the study of the reactions of H radicals with DNA, as the H 2 PO 4 - ions convert the hydrated electrons into H radicals. The hydrated electron, which does react with DNA, does not cause a detectable inactivation. (Auth.)

  8. Oxidative damage and cell-programmed death induced in Zea mays L. by allelochemical stress.

    Science.gov (United States)

    Ciniglia, Claudia; Mastrobuoni, Francesco; Scortichini, Marco; Petriccione, Milena

    2015-05-01

    The allelochemical stress on Zea mays was analyzed by using walnut husk washing waters (WHWW), a by-product of Juglans regia post-harvest process, which possesses strong allelopathic potential and phytotoxic effects. Oxidative damage and cell-programmed death were induced by WHWW in roots of maize seedlings. Treatment induced ROS burst, with excess of H2O2 content. Enzymatic activities of catalase were strongly increased during the first hours of exposure. The excess in malonildialdehyde following exposure to WHWW confirmed that oxidative stress severely damaged maize roots. Membrane alteration caused a decrease in NADPH oxidase activity along with DNA damage as confirmed by DNA laddering. The DNA instability was also assessed through sequence-related amplified polymorphism assay, thus suggesting the danger of walnut processing by-product and focusing the attention on the necessity of an efficient treatment of WHWW.

  9. The DNA damage response in mammalian oocytes

    Directory of Open Access Journals (Sweden)

    John eCarroll

    2013-06-01

    Full Text Available DNA damage is one of the most common insults that challenge all cells. To cope, an elaborate molecular and cellular response has evolved to sense, respond to and correct the damage. This allows the maintenance of DNA fidelity essential for normal cell viability and the prevention of genomic instability that can lead to tumour formation. In the context of oocytes, the impact of DNA damage is not one of tumour formation but of the maintenance of fertility. Mammalian oocytes are particularly vulnerable to DNA damage because physiologically they may lie dormant in the ovary for many years (>40 in humans until they receive the stimulus to grow and acquire the competence to become fertilized. The implication of this is that in some organisms, such as humans, oocytes face the danger of cumulative genetic damage for decades. Thus, the ability to detect and repair DNA damage is essential to maintain the supply of oocytes necessary for reproduction. Therefore, failure to confront DNA damage in oocytes could cause serious anomalies in the embryo that may be propagated in the form of mutations to the next generation allowing the appearance of hereditary disease. Despite the potential impact of DNA damage on reproductive capacity and genetic fidelity of embryos, the mechanisms available to the oocyte for monitoring and repairing such insults have remained largely unexplored until recently. Here, we review the different aspects of the response to DNA damage in mammalian oocytes. Specifically, we address the oocyte DNA damage response from embryonic life to adulthood and throughout oocyte development.

  10. Gene polymorphisms against DNA damage induced by hydrogen peroxide in leukocytes of healthy humans through comet assay: a quasi-experimental study

    Directory of Open Access Journals (Sweden)

    Klautau-Guimarães Maria N

    2010-05-01

    Full Text Available Abstract Background Normal cellular metabolism is well established as the source of endogenous reactive oxygen species which account for the background levels of oxidative DNA damage detected in normal tissue. Hydrogen peroxide imposes an oxidative stress condition on cells that can result in DNA damage, leading to mutagenesis and cell death. Several potentially significant genetic variants related to oxidative stress have already been identified, and angiotensin I-converting enzyme (ACE inhibitors have been reported as possible antioxidant agents that can reduce vascular oxidative stress in cardiovascular events. Methods We investigate the influences of haptoglobin, manganese superoxide dismutase (MnSOD Val9Ala, catalase (CAT -21A/T, glutathione peroxidase 1 (GPx-1 Pro198Leu, ACE (I/D and gluthatione S-transferases GSTM1 and GSTT1 gene polymorphisms against DNA damage and oxidative stress. These were induced by exposing leukocytes from peripheral blood of healthy humans (N = 135 to hydrogen peroxide (H2O2, and the effects were tested by comet assay. Blood samples were submitted to genotyping and comet assay (before and after treatment with H2O2 at 250 μM and 1 mM. Results After treatment with H2O2 at 250 μM, the GPx-1 polymorphism significantly influenced results of comet assay and a possible association of the Pro/Leu genotype with higher DNA damage was found. The highest or lowest DNA damage also depended on interaction between GPX-1/ACE and Hp/GSTM1T1 polymorphisms when hydrogen peroxide treatment increased oxidative stress. Conclusions The GPx-1 polymorphism and the interactions between GPX-1/ACE and Hp/GSTM1T1 can be determining factors for DNA oxidation provoked by hydrogen peroxide, and thus for higher susceptibility to or protection against oxidative stress suffered by healthy individuals.

  11. Progress on clustered DNA damage in radiation research

    International Nuclear Information System (INIS)

    Yang Li'na; Zhang Hong; Di Cuixia; Zhang Qiuning; Wang Xiaohu

    2012-01-01

    Clustered DNA damage which caused by high LET heavy ion radiation can lead to mutation, tumorigenesis and apoptosis. Promoting apoptosis of cancer cells is always the basis of cancer treatment. Clustered DNA damage has been the hot topic in radiobiology. The detect method is diversity, but there is not a detail and complete protocol to analyze clustered DNA damage. In order to provide reference for clustered DNA damage in the radiotherapy study, the clustered DNA damage characteristics, the latest progresses on clustered DNA damage and the detecting methods are reviewed and discussed in detail in this paper. (authors)

  12. MicroRNAs, the DNA damage response and cancer

    International Nuclear Information System (INIS)

    Wouters, Maikel D.; Gent, Dik C. van; Hoeijmakers, Jan H.J.; Pothof, Joris

    2011-01-01

    Many carcinogenic agents such as ultra-violet light from the sun and various natural and man-made chemicals act by damaging the DNA. To deal with these potentially detrimental effects of DNA damage, cells induce a complex DNA damage response (DDR) that includes DNA repair, cell cycle checkpoints, damage tolerance systems and apoptosis. This DDR is a potent barrier against carcinogenesis and defects within this response are observed in many, if not all, human tumors. DDR defects fuel the evolution of precancerous cells to malignant tumors, but can also induce sensitivity to DNA damaging agents in cancer cells, which can be therapeutically exploited by the use of DNA damaging treatment modalities. Regulation of and coordination between sub-pathways within the DDR is important for maintaining genome stability. Although regulation of the DDR has been extensively studied at the transcriptional and post-translational level, less is known about post-transcriptional gene regulation by microRNAs, the topic of this review. More specifically, we highlight current knowledge about DNA damage responsive microRNAs and microRNAs that regulate DNA damage response genes. We end by discussing the role of DNA damage response microRNAs in cancer etiology and sensitivity to ionizing radiation and other DNA damaging therapeutic agents.

  13. Specific transcripts are elevated in Saccharomyces cerevisiae in response to DNA damage

    International Nuclear Information System (INIS)

    McClanahan, T.; McEntee, K.

    1984-01-01

    Differential hybridization has been used to identify genes in Saccharomyces cerevisiae displaying increased transcript levels after treatment of cells with UV irradiation or with the mutagen/carcinogen 4-nitroquinoline-1-oxide (NQO). The authors describe the isolation and characterization of four DNA damage responsive genes obtained from screening ca. 9000 yeast genomic clones. Two of these clones, lambda 78A and pBR178C, contain repetitive elements in the yeast genome as shown by Southern hybridization analysis. Although the genomic hybridization pattern is distinct for each of these two clones, both of these sequences hybridize to large polyadenylated transcripts ca. 5 kilobases in length. Two other DNA damage responsive sequences, pBRA2 and pBR3016B, are single-copy genes and hybridize to 0.5- and 3.2-kilobase transcripts, respectively. Kinetic analysis of the 0.5-kilobase transcript homologous to pBRA2 indicates that the level of this RNA increases more than 15-fold within 20 min after exposure to 4-nitroquinoline-1-oxide. Moreover, the level of this transcript is significantly elevated in cells containing the rad52-1 mutation which are deficient in DNA strand break repair and gene conversion. These results provide some of the first evidence that DNA damage stimulates transcription of specific genes in eucaryotic cells

  14. The DNA damage response during mitosis

    NARCIS (Netherlands)

    Heijink, Anne Margriet; Krajewska, Malgorzata; van Vugt, Marcel A. T. M.

    2013-01-01

    Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance

  15. Increased levels of oxidative DNA damage in pesticide sprayers in Thessaly Region (Greece). Implications of pesticide exposure.

    Science.gov (United States)

    Koureas, Michalis; Tsezou, Aspasia; Tsakalof, Andreas; Orfanidou, Timoklia; Hadjichristodoulou, Christos

    2014-10-15

    The widespread use of pesticides substances nowadays largely guarantees the protection of crops and people from undesired pests. However, exposure to pesticides was related to a variety of human health effects. The present study was conducted in the region of Thessaly which is characterized by intensive agricultural activities and wide use of pesticides. The study aimed at estimating the oxidative damage to DNA in different subpopulations in Thessaly region (Greece) and investigating its correlation with exposure to pesticides and other potential risk factors. In total, the study involved 80 pesticide sprayers, 85 rural residents and 121 individuals, inhabitants of the city of Larissa. Demographic characteristics, habits, medical history and exposure history of the participants to pesticides were recorded by personal interviews. Blood and urine samples were collected from all participants. For the measurement of exposure to organophosphorus insecticides, dialkylphosphate (DAP) metabolites were quantified in urine, by gas chromatography-mass spectrometry. Genomic DNA was extracted from peripheral blood samples and the oxidation by-product 8-hydroxydeoxyguanosine (8-OHdG) was determined by Enzyme Immuno-Assay. Urinary metabolite concentrations were not associated with 8-OHdG levels but it was found that pesticide sprayers had significantly higher levels of 8-OHdG (p=0.007) in comparison to the control group. Last season's exposure to insecticides and fungicides, expressed as total area treated multiplied by the number of applications, showed a statistically significant association with the risk of having high 8-OHdG levels [RR: 2.19 (95%CI:1.09-4.38) and RR: 2.32 (95% CI:1.16-4.64) respectively]. Additionally, from the subgroups of pesticides examined, seasonal exposure to neonicotinoid insecticides [RR: 2.22 (95% CI:1.07-4.63)] and glufosinate ammonium [RR: 3.26 (95% CI:1.38-7.69)] was found to have the greater impact on 8-OHdG levels. This study produced findings

  16. Early models of DNA damage formation

    International Nuclear Information System (INIS)

    Śmiałek, Małgorzata A

    2012-01-01

    Quantification of DNA damage, induced by various types of incident radiation as well as chemical agents, has been the subject of many theoretical and experimental studies, supporting the development of modern cancer therapy. The primary observations showed that many factors can lead to damage of DNA molecules. It became clear that the development of experimental techniques for exploring this phenomenon is required. Another problem was simultaneously dealt with, anticipating on how the damage is distributed within the double helix of the DNA molecule and how the single strand break formation and accumulation can influence the lethal double strand break formation. In this work the most important probabilistic models for DNA strand breakage and damage propagation are summarized and compared.

  17. The thyroid hormone receptor β induces DNA damage and premature senescence.

    Science.gov (United States)

    Zambrano, Alberto; García-Carpizo, Verónica; Gallardo, María Esther; Villamuera, Raquel; Gómez-Ferrería, Maria Ana; Pascual, Angel; Buisine, Nicolas; Sachs, Laurent M; Garesse, Rafael; Aranda, Ana

    2014-01-06

    There is increasing evidence that the thyroid hormone (TH) receptors (THRs) can play a role in aging, cancer and degenerative diseases. In this paper, we demonstrate that binding of TH T3 (triiodothyronine) to THRB induces senescence and deoxyribonucleic acid (DNA) damage in cultured cells and in tissues of young hyperthyroid mice. T3 induces a rapid activation of ATM (ataxia telangiectasia mutated)/PRKAA (adenosine monophosphate-activated protein kinase) signal transduction and recruitment of the NRF1 (nuclear respiratory factor 1) and THRB to the promoters of genes with a key role on mitochondrial respiration. Increased respiration leads to production of mitochondrial reactive oxygen species, which in turn causes oxidative stress and DNA double-strand breaks and triggers a DNA damage response that ultimately leads to premature senescence of susceptible cells. Our findings provide a mechanism for integrating metabolic effects of THs with the tumor suppressor activity of THRB, the effect of thyroidal status on longevity, and the occurrence of tissue damage in hyperthyroidism.

  18. Oxidative DNA base modifications as factors in carcinogenesis

    International Nuclear Information System (INIS)

    Olinski, R.; Jaruga, P.; Zastawny, T.H.

    1998-01-01

    Reactive oxygen species can cause extensive DNA modifications including modified bases. Some of the DNA base damage has been found to possess premutagenic properties. Therefore, if not repaired, it can contribute to carcinogenesis. We have found elevated amounts of modified bases in cancerous and precancerous tissues as compared with normal tissues. Most of the agents used in anticancer therapy are paradoxically responsible for induction of secondary malignancies and some of them may generate free radicals. The results of our experiments provide evidence that exposure of cancer patients to therapeutic doses of ionizing radiation and anticancer drugs cause base modifications in genomic DNA of lymphocytes. Some of these base damages could lead to mutagenesis in critical genes and ultimately to secondary cancers such as leukemias. This may point to an important role of oxidative base damage in cancer initiation. Alternatively, the increased level of the modified base products may contribute to genetic instability and metastatic potential of tumor cells. (author)

  19. Increased systemic oxidatively generated DNA and RNA damage in schizophrenia

    DEFF Research Database (Denmark)

    Jørgensen, Anders; Brødbæk, Kasper; Fink-Jensen, Anders

    2013-01-01

    such as cardiovascular disease, type 2 diabetes and dementia. We determined the urinary excretion of markers of systemic Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) oxidation, 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydroguanosine, respectively, in 40 schizophrenia patients and 40 age- and sex...

  20. Damage to cellular and isolated DNA induced by a metabolite of aspirin

    Energy Technology Data Exchange (ETDEWEB)

    Oikawa, Shinji [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514-8507 (Japan)], E-mail: s-oikawa@doc.medic.mie-u.ac.jp; Kobayashi, Hatasu; Tada-Oikawa, Saeko [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514-8507 (Japan); JSPS Research Fellow (Japan); Isono, Yoshiaki [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514-8507 (Japan); Kawanishi, Shosuke [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514-8507 (Japan); Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Mie 513-8670 (Japan)

    2009-02-10

    Aspirin has been proposed as a possible chemopreventive agent. On the other hand, a recent cohort study showed that aspirin may increase the risk for pancreatic cancer. To clarify whether aspirin is potentially carcinogenic, we investigated the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), which is correlated with the incidence of cancer, in cultured cells treated with 2,3-dihydroxybenzoic acid (2,3-DHBA), a metabolite of aspirin. 2,3-DHBA induced 8-oxodG formation in the PANC-1 human pancreatic cancer cell line. 2,3-DHBA-induced DNA single-strand breaks were also revealed by comet assay using PANC-1 cells. Flow cytometric analyses showed that 2,3-DHBA increased the levels of intracellular reactive oxygen species (ROS) in PANC-1 cells. The 8-oxodG formation and ROS generation were also observed in the HL-60 leukemia cell line, but not in the hydrogen peroxide (H{sub 2}O{sub 2})-resistant clone HP100 cells, suggesting the involvement of H{sub 2}O{sub 2}. In addition, an hprt mutation assay supported the mutagenicity of 2,3-DHBA. We investigated the mechanism underlying the 2,3-DHBA-induced DNA damage using {sup 32}P-labeled DNA fragments of human tumor suppressor genes. 2,3-DHBA induced DNA damage in the presence of Cu(II) and NADH. DNA damage induced by 2,3-DHBA was enhanced by the addition of histone peptide-6 [AKRHRK]. Interestingly, 2,3-DHBA and histone peptide-6 caused base damage in the 5'-ACG-3' and 5'-CCG-3' sequences, hotspots of the p53 gene. Bathocuproine, a Cu(I) chelator, and catalase inhibited the DNA damage. Typical hydroxyl radical scavengers did not inhibit the DNA damage. These results suggest that ROS derived from the reaction of H{sub 2}O{sub 2} with Cu(I) participate in the DNA damage. In conclusion, 2,3-DHBA induces oxidative DNA damage and mutations, which may result in carcinogenesis.

  1. Damage to cellular and isolated DNA induced by a metabolite of aspirin

    International Nuclear Information System (INIS)

    Oikawa, Shinji; Kobayashi, Hatasu; Tada-Oikawa, Saeko; Isono, Yoshiaki; Kawanishi, Shosuke

    2009-01-01

    Aspirin has been proposed as a possible chemopreventive agent. On the other hand, a recent cohort study showed that aspirin may increase the risk for pancreatic cancer. To clarify whether aspirin is potentially carcinogenic, we investigated the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), which is correlated with the incidence of cancer, in cultured cells treated with 2,3-dihydroxybenzoic acid (2,3-DHBA), a metabolite of aspirin. 2,3-DHBA induced 8-oxodG formation in the PANC-1 human pancreatic cancer cell line. 2,3-DHBA-induced DNA single-strand breaks were also revealed by comet assay using PANC-1 cells. Flow cytometric analyses showed that 2,3-DHBA increased the levels of intracellular reactive oxygen species (ROS) in PANC-1 cells. The 8-oxodG formation and ROS generation were also observed in the HL-60 leukemia cell line, but not in the hydrogen peroxide (H 2 O 2 )-resistant clone HP100 cells, suggesting the involvement of H 2 O 2 . In addition, an hprt mutation assay supported the mutagenicity of 2,3-DHBA. We investigated the mechanism underlying the 2,3-DHBA-induced DNA damage using 32 P-labeled DNA fragments of human tumor suppressor genes. 2,3-DHBA induced DNA damage in the presence of Cu(II) and NADH. DNA damage induced by 2,3-DHBA was enhanced by the addition of histone peptide-6 [AKRHRK]. Interestingly, 2,3-DHBA and histone peptide-6 caused base damage in the 5'-ACG-3' and 5'-CCG-3' sequences, hotspots of the p53 gene. Bathocuproine, a Cu(I) chelator, and catalase inhibited the DNA damage. Typical hydroxyl radical scavengers did not inhibit the DNA damage. These results suggest that ROS derived from the reaction of H 2 O 2 with Cu(I) participate in the DNA damage. In conclusion, 2,3-DHBA induces oxidative DNA damage and mutations, which may result in carcinogenesis

  2. Antioxidant effect of naturally occurring xanthines on the oxidative damage of DNA bases

    International Nuclear Information System (INIS)

    Vieira, A.J.S.C.; Telo, J.P.; Pereira, H.F.; Patrocinio, P.F.; Dias, R.M.B.

    1999-01-01

    The repair of the oxidised radicals of adenine and guanosine by several naturally occurring xanthines was studied. Each pair of DNA purine/xanthine was made to react with the sulphate radical and the decrease of the concentration of both compounds was measured by HPLC as a function of irradiation time. The results show that xanthine efficiently prevents the oxidation of the two DNA purines. Theophylline and para-xanthine repair the oxidizes radical of adenine but not the one from guanosine. Theobromine and caffeine to do not show any protecting effect. An order of the oxidation potentials of all the purines studied is proposed. (authors)

  3. Cytoprotective effect against UV-induced DNA damage and oxidative stress: role of new biological UV filter.

    Science.gov (United States)

    Said, T; Dutot, M; Martin, C; Beaudeux, J-L; Boucher, C; Enee, E; Baudouin, C; Warnet, J-M; Rat, P

    2007-03-01

    The majority of chemical solar filters are cytotoxic, particularly on sensitive ocular cells (corneal and conjunctival cells). Consequently, a non-cytotoxic UV filter would be interesting in dermatology, but more especially in ophthalmology. In fact, light damage to the eye can be avoided thanks to a very efficient ocular antioxidant system; indeed, the chromophores absorb light and dissipate its energy. After middle age, a decrease in the production of antioxidants and antioxidative enzymes appears with accumulation of endogenous molecules that are phototoxic. UV radiations can induce reactive oxygen species formation, leading to various ocular diseases. Because most UV filters are cytotoxic for the eye, we investigated the anti-UV properties of Calophyllum inophyllum oil in order to propose it as a potential vehicle, free of toxicity, with a natural UV filter action in ophthalmic formulation. Calophyllum inophyllum oil, even at low concentration (1/10,000, v/v), exhibited significant UV absorption properties (maximum at 300nm) and was associated with an important sun protection factor (18-22). Oil concentrations up to 1% were not cytotoxic on human conjunctival epithelial cells, and Calophyllum inophyllum oil appeared to act as a cytoprotective agent against oxidative stress and DNA damage (85% of the DNA damage induced by UV radiations were inhibited with 1% Calophyllum oil) and did not induce in vivo ocular irritation (Draize test on New Zealand rabbits). Calophyllum inophyllum oil thus exhibited antioxidant and cytoprotective properties, and therefore might serve, for the first time, as a natural UV filter in ophthalmic preparations.

  4. Scavenging of peroxynitrite by phycocyanin and phycocyanobilin from Spirulina platensis: protection against oxidative damage to DNA.

    Science.gov (United States)

    Bhat, V B; Madyastha, K M

    2001-07-13

    Peroxynitrite (ONOO(-)) is known to inactivate important cellular targets and also mediate oxidative damage in DNA. The present study has demonstrated that phycocyanin, a biliprotein from spirulina platensis and its chromophore, phycocyanobilin (PCB), efficiently scavenge ONOO(-), a potent physiological inorganic toxin. Scavenging of ONOO(-) by phycocyanin and PCB was established by studying their interaction with ONOO(-) and quantified by using competition kinetics of pyrogallol red bleaching assay. The relative antioxidant ratio and IC(50) value clearly indicate that phycocyanin is a more efficient ONOO(-) scavenger than PCB. The present study has also shown that PCB significantly inhibits the ONOO(-)-mediated single-strand breaks in supercoiled plasmid DNA in a dose-dependent manner with an IC(50) value of 2.9 +/- 0.6 microM. These results suggest that phycocyanin, has the ability to inhibit the ONOO(-)-mediated deleterious biological effects and hence has the potential to be used as a therapeutic agent. Copyright 2001 Academic Press.

  5. Haloperidol-loaded lipid-core polymeric nanocapsules reduce DNA damage in blood and oxidative stress in liver and kidneys of rats

    International Nuclear Information System (INIS)

    Roversi, Katiane; Benvegnú, Dalila M.; Roversi, Karine; Trevizol, Fabíola; Vey, Luciana T.; Elias, Fabiana; Fracasso, Rafael

    2015-01-01

    Haloperidol (HP) nanoencapsulation improves therapeutic efficacy, prolongs the drug action time, and reduces its motor side effects. However, in a view of HP toxicity in organs like liver and kidneys in addition to the lack of knowledge regarding the toxicity of polymeric nanocapsules, our aim was to verify the influence of HP-nanoformulation on toxicity and oxidative stress markers in the liver and kidneys of rats, also observing the damage caused in the blood. For such, 28 adult male Wistar rats were designated in four experimental groups (n = 7) and treated with vehicle (C group), free haloperidol suspension (FH group), blank nanocapsules suspension (B-Nc group), and haloperidol-loaded lipid-core nanocapsules suspension (H-Nc group). The nanocapsules formulation presented the size of approximately 250 nm. All suspensions were administered to the animals (0.5 mg/kg/day-i.p.) for a period of 28 days. Our results showed that FH caused damage in the liver, evidenced by increased lipid peroxidation, plasma levels of aspartate aminotransferase, and alanine aminotransferase, as well as decreased cellular integrity and vitamin C levels. In kidneys, FH treatment caused damage to a lesser extent, observed by decreased activity of δ-aminolevulinate dehydratase (ALA-D) and levels of VIT C. In addition, FH treatment was also related to a higher DNA damage index in blood. On the other hand, animals treated with H-Nc and B-Nc did not show damage in liver, kidneys, and DNA. Our study indicates that the nanoencapsulation of haloperidol was able to prevent the sub-chronic toxicity commonly observed in liver, kidneys, and DNA, thus reflecting a pharmacological superiority in relation to free drug

  6. Haloperidol-loaded lipid-core polymeric nanocapsules reduce DNA damage in blood and oxidative stress in liver and kidneys of rats

    Science.gov (United States)

    Roversi, Katiane; Benvegnú, Dalila M.; Roversi, Karine; Trevizol, Fabíola; Vey, Luciana T.; Elias, Fabiana; Fracasso, Rafael; Motta, Mariana H.; Ribeiro, Roseane F.; dos S. Hausen, Bruna; Moresco, Rafael N.; Garcia, Solange C.; da Silva, Cristiane B.; Burger, Marilise E.

    2015-04-01

    Haloperidol (HP) nanoencapsulation improves therapeutic efficacy, prolongs the drug action time, and reduces its motor side effects. However, in a view of HP toxicity in organs like liver and kidneys in addition to the lack of knowledge regarding the toxicity of polymeric nanocapsules, our aim was to verify the influence of HP-nanoformulation on toxicity and oxidative stress markers in the liver and kidneys of rats, also observing the damage caused in the blood. For such, 28 adult male Wistar rats were designated in four experimental groups ( n = 7) and treated with vehicle (C group), free haloperidol suspension (FH group), blank nanocapsules suspension (B-Nc group), and haloperidol-loaded lipid-core nanocapsules suspension (H-Nc group). The nanocapsules formulation presented the size of approximately 250 nm. All suspensions were administered to the animals (0.5 mg/kg/day-i.p.) for a period of 28 days. Our results showed that FH caused damage in the liver, evidenced by increased lipid peroxidation, plasma levels of aspartate aminotransferase, and alanine aminotransferase, as well as decreased cellular integrity and vitamin C levels. In kidneys, FH treatment caused damage to a lesser extent, observed by decreased activity of δ-aminolevulinate dehydratase (ALA-D) and levels of VIT C. In addition, FH treatment was also related to a higher DNA damage index in blood. On the other hand, animals treated with H-Nc and B-Nc did not show damage in liver, kidneys, and DNA. Our study indicates that the nanoencapsulation of haloperidol was able to prevent the sub-chronic toxicity commonly observed in liver, kidneys, and DNA, thus reflecting a pharmacological superiority in relation to free drug.

  7. Haloperidol-loaded lipid-core polymeric nanocapsules reduce DNA damage in blood and oxidative stress in liver and kidneys of rats

    Energy Technology Data Exchange (ETDEWEB)

    Roversi, Katiane, E-mail: katianeroversi@gmail.com [Universidade Federal de Santa Maria, Programa de Pós-Graduação em Farmacologia (Brazil); Benvegnú, Dalila M., E-mail: dalilabenvegnu@yahoo.com.br [Universidade Federal da Fronteira Sul (UFFS), Bioquímica e Farmacologia (Brazil); Roversi, Karine, E-mail: karineroversi-@hotmail.com [Universidade Federal de Santa Maria (UFSM), Departamento de Fisiologia e Farmacologia, Centro de Ciências da Saúde (Brazil); Trevizol, Fabíola, E-mail: fatrevizol@yahoo.com.br [Universidade Federal de Santa Maria, Programa de Pós-Graduação em Farmacologia (Brazil); Vey, Luciana T., E-mail: luciana.taschetto@hotmail.com [Universidade Federal de Santa Maria (UFSM), Departamento de Fisiologia e Farmacologia, Centro de Ciências da Saúde (Brazil); Elias, Fabiana, E-mail: fabiana.elias@uffs.edu.br [Universidade Federal da Fronteira Sul (UFFS), Bioquímica e Farmacologia (Brazil); Fracasso, Rafael, E-mail: rafael.fra@hotmail.com [Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Ciências Farmacêuticas (Brazil); and others

    2015-04-15

    Haloperidol (HP) nanoencapsulation improves therapeutic efficacy, prolongs the drug action time, and reduces its motor side effects. However, in a view of HP toxicity in organs like liver and kidneys in addition to the lack of knowledge regarding the toxicity of polymeric nanocapsules, our aim was to verify the influence of HP-nanoformulation on toxicity and oxidative stress markers in the liver and kidneys of rats, also observing the damage caused in the blood. For such, 28 adult male Wistar rats were designated in four experimental groups (n = 7) and treated with vehicle (C group), free haloperidol suspension (FH group), blank nanocapsules suspension (B-Nc group), and haloperidol-loaded lipid-core nanocapsules suspension (H-Nc group). The nanocapsules formulation presented the size of approximately 250 nm. All suspensions were administered to the animals (0.5 mg/kg/day-i.p.) for a period of 28 days. Our results showed that FH caused damage in the liver, evidenced by increased lipid peroxidation, plasma levels of aspartate aminotransferase, and alanine aminotransferase, as well as decreased cellular integrity and vitamin C levels. In kidneys, FH treatment caused damage to a lesser extent, observed by decreased activity of δ-aminolevulinate dehydratase (ALA-D) and levels of VIT C. In addition, FH treatment was also related to a higher DNA damage index in blood. On the other hand, animals treated with H-Nc and B-Nc did not show damage in liver, kidneys, and DNA. Our study indicates that the nanoencapsulation of haloperidol was able to prevent the sub-chronic toxicity commonly observed in liver, kidneys, and DNA, thus reflecting a pharmacological superiority in relation to free drug.

  8. Role of oxidative damage in toxicity of particulates

    DEFF Research Database (Denmark)

    Møller, Peter; Jacobsen, Nicklas R; Folkmann, Janne K

    2010-01-01

    composition play important roles in the oxidative potential of particulates. Studies in animal models indicate that particles from combustion processes (generated by combustion of wood or diesel oil), silicate, titanium dioxide and nanoparticles (C60 fullerenes and carbon nanotubes) produce elevated levels......Particulates are small particles of solid or liquid suspended in liquid or air. In vitro studies show that particles generate reactive oxygen species, deplete endogenous antioxidants, alter mitochondrial function and produce oxidative damage to lipids and DNA. Surface area, reactivity and chemical...

  9. Detection of DNA damage based on metal-mediated molecular beacon and DNA strands displacement reaction

    Science.gov (United States)

    Xiong, Yanxiang; Wei, Min; Wei, Wei; Yin, Lihong; Pu, Yuepu; Liu, Songqin

    2014-01-01

    DNA hairpin structure probes are usually designed by forming intra-molecular duplex based on Watson-Crick hydrogen bonds. In this paper, a molecular beacon based on silver ions-mediated cytosine-Ag+-cytosine base pairs was used to detect DNA. The inherent characteristic of the metal ligation facilitated the design of functional probe and the adjustment of its binding strength compared to traditional DNA hairpin structure probes, which make it be used to detect DNA in a simple, rapid and easy way with the help of DNA strands displacement reaction. The method was sensitive and also possesses the good specificity to differentiate the single base mismatched DNA from the complementary DNA. It was also successfully applied to study the damage effect of classic genotoxicity chemicals such as styrene oxide and sodium arsenite on DNA, which was significant in food science, environmental science and pharmaceutical science.

  10. Recent Advancements in DNA Damage-Transcription Crosstalk and High-Resolution Mapping of DNA Breaks.

    Science.gov (United States)

    Vitelli, Valerio; Galbiati, Alessandro; Iannelli, Fabio; Pessina, Fabio; Sharma, Sheetal; d'Adda di Fagagna, Fabrizio

    2017-08-31

    Until recently, DNA damage arising from physiological DNA metabolism was considered a detrimental by-product for cells. However, an increasing amount of evidence has shown that DNA damage could have a positive role in transcription activation. In particular, DNA damage has been detected in transcriptional elements following different stimuli. These physiological DNA breaks are thought to be instrumental for the correct expression of genomic loci through different mechanisms. In this regard, although a plethora of methods are available to precisely map transcribed regions and transcription start sites, commonly used techniques for mapping DNA breaks lack sufficient resolution and sensitivity to draw a robust correlation between DNA damage generation and transcription. Recently, however, several methods have been developed to map DNA damage at single-nucleotide resolution, thus providing a new set of tools to correlate DNA damage and transcription. Here, we review how DNA damage can positively regulate transcription initiation, the current techniques for mapping DNA breaks at high resolution, and how these techniques can benefit future studies of DNA damage and transcription.

  11. Pristanic acid provokes lipid, protein, and DNA oxidative damage and reduces the antioxidant defenses in cerebellum of young rats.

    Science.gov (United States)

    Busanello, Estela Natacha Brandt; Lobato, Vannessa Gonçalves Araujo; Zanatta, Ângela; Borges, Clarissa Günther; Tonin, Anelise Miotti; Viegas, Carolina Maso; Manfredini, Vanusa; Ribeiro, César Augusto João; Vargas, Carmen Regla; de Souza, Diogo Onofre Gomes; Wajner, Moacir

    2014-12-01

    Zellweger syndrome (ZS) and some peroxisomal diseases are severe inherited disorders mainly characterized by neurological symptoms and cerebellum abnormalities, whose pathogenesis is poorly understood. Biochemically, these diseases are mainly characterized by accumulation of pristanic acid (Prist) and other fatty acids in the brain and other tissues. In this work, we evaluated the in vitro influence of Prist on redox homeostasis by measuring lipid, protein, and DNA damage, as well as the antioxidant defenses and the activities of aconitase and α-ketoglutarate dehydrogenase in cerebellum of 30-day-old rats. The effect of Prist on DNA damage was also evaluated in blood of these animals. Some parameters were also evaluated in cerebellum from neonatal rats and in cerebellum neuronal cultures. Prist significantly increased malondialdehyde (MDA) levels and carbonyl formation and reduced sulfhydryl content and glutathione (GSH) concentrations in cerebellum of young rats. It also caused DNA strand damage in cerebellum and induced a high micronuclei frequency in blood. On the other hand, this fatty acid significantly reduced α-ketoglutarate dehydrogenase and aconitase activities in rat cerebellum. We also verified that Prist-induced increase of MDA levels was totally prevented by melatonin and attenuated by α-tocopherol but not by the nitric oxide synthase inhibitor N(ω)-nitro-L-arginine methyl ester, indicating the involvement of reactive oxygen species in this effect. Cerebellum from neonate rats also showed marked alterations of redox homeostasis, including an increase of MDA levels and a decrease of sulfhydryl content and GSH concentrations elicited by Prist. Finally, Prist provoked an increase of dichlorofluorescein (DCFH) oxidation in cerebellum-cultivated neurons. Our present data indicate that Prist compromises redox homeostasis in rat cerebellum and blood and inhibits critical enzymes of the citric acid cycle that are susceptible to free radical attack. The

  12. Oxidative stress damage-associated molecular signaling pathways differentiate spontaneous preterm birth and preterm premature rupture of the membranes.

    Science.gov (United States)

    Dutta, Eryn H; Behnia, Faranak; Boldogh, Istvan; Saade, George R; Taylor, Brandie D; Kacerovský, Marian; Menon, Ramkumar

    2016-02-01

    In women with preterm premature rupture of the membranes (PPROM), increased oxidative stress may accelerate premature cellular senescence, senescence-associated inflammation and proteolysis, which may predispose them to rupture. We demonstrate mechanistic differences between preterm birth (PTB) and PPROM by revealing differences in fetal membrane redox status, oxidative stress-induced damage, distinct signaling pathways and senescence activation. Oxidative stress-associated fetal membrane damage and cell cycle arrest determine adverse pregnancy outcomes, such as spontaneous PTB and PPROM. Fetal membranes and amniotic fluid samples were collected from women with PTB and PPROM. Molecular, biochemical and histologic markers were used to document differences in oxidative stress and antioxidant enzyme status, DNA damage, secondary signaling activation by Ras-GTPase and mitogen-activated protein kinases, and activation of senescence between membranes from the two groups. Oxidative stress was higher and antioxidant enzymes were lower in PPROM compared with PTB. PTB membranes had minimal DNA damage and showed activation of Ras-GTPase and ERK/JNK signaling pathway with minimal signs of senescence. PPROM had higher numbers of cells with DNA damage, prosenescence stress kinase (p38 MAPK) activation and signs of senescence. Samples were obtained retrospectively after delivery. The markers of senescence that we tested are specific but are not sufficient to confirm senescence as the pathology in PPROM. Oxidative stress-induced DNA damage and senescence are characteristics of fetal membranes from PPROM, compared with PTB with intact membranes. PTB and PPROM arise from distinct pathophysiologic pathways. Oxidative stress and oxidative stress-induced cellular damages are likely determinants of the mechanistic signaling pathways and phenotypic outcome. This study is supported by developmental funds to Dr R. Menon from the Department of Obstetrics and Gynecology at The University of

  13. Carcinogen-induced damage to DNA

    International Nuclear Information System (INIS)

    Strauss, B.; Altamirano, M.; Bose, K.; Sklar, R.; Tatsumi, K.

    1979-01-01

    Human cells respond to carcinogen-induced damage in their DNA in at least two ways. The first response, excision repair, proceeds by at least three variations, depending on the nature of the damage. Nucleotide excision results in relatively large repair patches but few free DNA breaks, since the endonuclease step is limiting. Apurinic repair is characterized by the appearance of numerous breaks in the DNA and by short repair patches. The pathways behave as though they function independently. Lymphoic cells derived from a xeroderma pigmentosum complementation group C patient are deficient in their ability to perform nucleotide excision and also to excise 6 methoxyguanine adducts, but they are apurinic repair competent. Organisms may bypass damage in their DNA. Lymphoblastoid cells, including those derived from xeroderma pigmentosum treated with 3 H-anti-BPDE, can replicate their DNA at low doses of carcinogen. Unexcised 3 H is found in the light or parental strand of the resulting hybrid DNA when replication occurs in medium with BrdUrd. This observation indicates a bypass reaction occurring by a mechanism involving branch migration at DNA growing points. Branch migration in DNA preparations have been observed, but the evidence is that most occurs in BrdUrd-containing DNA during cell lysis. The measurement of the bifilarly substituted DNA resulting from branch migration is a convenient method of estimating the proportion of new synthesis remaining in the vicinity of the DNA growing point. Treatment with carcinogens or caffeine results in accumulation of DNA growing points accompanied by the synthesis of shortened pieces of daughter DNA

  14. Repair of DNA damage in Deinococcus radiodurans

    International Nuclear Information System (INIS)

    Evans, D.M.

    1984-01-01

    The repair of DNA lesions in Deinococcus radiodurans was examined with particular reference to DNA excision repair of ultraviolet light (UV) induced pyrimidine dimers. The characteristics of excision repair via UV endonucleases α and β in vivo varied with respect to (a) the substrate range of the enzymes, (b) the rate of repair of DNA damage (c) the requirement for a protein synthesised in response to DNA damage to attenuate exonuclease action at repairing regions. UV endonuclease α is postulated to incise DNA in a different manner from UV endonuclease β thus defining the method of subsequent repair. Several DNA damage specific endonuclease activities independent of α and β are described. Mutations of the uvsA, uvsF and uvsG genes resulted in an increase in single-strand breaks in response to DNA damage producing uncontrolled DNA degradation. Evidence is presented that these genes have a role in limiting the access of UV endonuclease β to DNA lesions. uvsF and uvsG are also shown to be linked to the mtoA gene. Mutation of uvsH and reo-1 produces further distinct phenotypes which are discussed. An overall model of excision repair of DNA damage in Deinococcus radiodurans is presented. (author)

  15. Molecular mechanisms in radiation damage to DNA

    International Nuclear Information System (INIS)

    Osman, R.

    1991-01-01

    The objectives of this work are to elucidate the molecular mechanisms that are responsible for radiation-induced DNA damage. The overall goal is to understand the relationship between the chemical and structural changes produced by ionizing radiation in DNA and the resulting impairment of biological function expressed as carcinogenesis or cell death. The studies are based on theoretical explorations of possible mechanisms that link initial radiation damage in the form of base and sugar damage to conformational changes in DNA. These mechanistic explorations should lead to the formulation of testable hypothesis regarding the processes of impairment of regulation of gene expression, alternation in DNA repair, and damage to DNA structure involved in cell death or cancer

  16. Autophagy in DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Piotr Czarny

    2015-01-01

    Full Text Available DNA damage response (DDR involves DNA repair, cell cycle regulation and apoptosis, but autophagy is also suggested to play a role in DDR. Autophagy can be activated in response to DNA-damaging agents, but the exact mechanism underlying this activation is not fully understood, although it is suggested that it involves the inhibition of mammalian target of rapamycin complex 1 (mTORC1. mTORC1 represses autophagy via phosphorylation of the ULK1/2–Atg13–FIP200 complex thus preventing maturation of pre-autophagosomal structures. When DNA damage occurs, it is recognized by some proteins or their complexes, such as poly(ADPribose polymerase 1 (PARP-1, Mre11–Rad50–Nbs1 (MRN complex or FOXO3, which activate repressors of mTORC1. SQSTM1/p62 is one of the proteins whose levels are regulated via autophagic degradation. Inhibition of autophagy by knockout of FIP200 results in upregulation of SQSTM1/p62, enhanced DNA damage and less efficient damage repair. Mitophagy, one form of autophagy involved in the selective degradation of mitochondria, may also play role in DDR. It degrades abnormal mitochondria and can either repress or activate apoptosis, but the exact mechanism remains unknown. There is a need to clarify the role of autophagy in DDR, as this process may possess several important biomedical applications, involving also cancer therapy.

  17. Bioactivation of carboxylic acid compounds by UDP-Glucuronosyltransferases to DNA-damaging intermediates: role of glycoxidation and oxidative stress in genotoxicity.

    Science.gov (United States)

    Sallustio, Benedetta C; Degraaf, Yvette C; Weekley, Josephine S; Burcham, Philip C

    2006-05-01

    Nonenzymatic modification of proteins by acyl glucuronides is well documented; however, little is known about their potential to damage DNA. We have previously reported that clofibric acid undergoes glucuronidation-dependent bioactivation to DNA-damaging species in cultured mouse hepatocytes. The aim of this study was to investigate the mechanisms underlying such DNA damage, and to screen chemically diverse carboxylic acid drugs for their DNA-damaging potential in glucuronidation proficient murine hepatocytes. Cells were incubated with each aglycone for 18 h, followed by assessment of compound cytotoxicity using the MTT assay and evaluation of DNA damage using the Comet assay. Relative cytotoxic potencies were ketoprofen > diclofenac, benoxaprofen, nafenopin > gemfibrozil, probenecid > bezafibrate > clofibric acid. At a noncytotoxic (0.1 mM) concentration, only benoxaprofen, nafenopin, clofibric acid, and probenecid significantly increased Comet moments (P Clofibric acid and probenecid exhibited the greatest DNA-damaging potency, producing significant DNA damage at 0.01 mM concentrations. The two drugs produced maximal increases in Comet moment of 4.51 x and 2.57 x control, respectively. The glucuronidation inhibitor borneol (1 mM) abolished the induction of DNA damage by 0.5 mM concentrations of clofibric acid and probenecid. In an in vitro cell-free system, clofibric acid glucuronide was 10 x more potent than glucuronic acid in causing DNA strand-nicking, although both compounds showed similar rates of autoxidation to generate hydroxyl radicals. In cultured hepatocytes, the glycation inhibitor, aminoguanidine, and the iron chelator, desferrioxamine mesylate, inhibited DNA damage by clofibric acid, whereas the free radical scavengers Trolox and butylated hydroxytoluene, and the superoxide dismutase mimetic bis-3,5-diisopropylsalicylate had no effect. In conclusion, clinically relevant concentrations of two structurally unrelated carboxylic acids, probenecid and

  18. Measurement of spontaneous DNA damage and DNA repair capacity in healthy adult individuals from high and normal level natural radiation areas of Kerala, India

    International Nuclear Information System (INIS)

    Vivek Kumar, P.R.; Jaikrishan, G.; Das, Birajalaxmi

    2014-01-01

    Inhabitants of the south west coastal areas of Kerala receive high level natural radiation due to the presence of monazite ( 232 Th) in the beach sand. This provides a unique opportunity to investigate the biological effects of high level natural radiation on humans. This study evaluate basal DNA damage in 149 healthy adult male subjects (104 from high level natural radiation areas (HLNRA, > 1mSv year -1 ) and 45 from normal level natural radiation area (NLNRA, d''1mSv year -1 ) by the alkaline comet assay. Oxidative DNA damage (ENDO III, FPG and hOGG1-sensitive sites) was measured by the enzyme modified comet assay. Induction and rejoining of DNA strand breaks was measured after irradiating peripheral blood lymphocytes with 2 Gy or 4 Gy gamma radiation. Basal damage due to age and residential area of the donors showed significant interaction (P=0.001), when all subjects were analyzed using a general linear model (GLM). In subgroup analysis, basal damage increased with age in subjects from the NLNRA (P=0.007), while a significant negative correlation (P=0.01) was observed in subjects from HLNRA. Oxidative DNA damage was not influenced by age, smoking habit or residential area in the entire sample. Subjects of high dose group from HLNRA (>5.75 mSv/y, N=34) showed a significant reduction in the induction of DNA damage after 2 Gy (P=0.03) and 4 Gy (P=0.05) compared to subjects form NLNRA. The study showed increased rejoining of DNA strand breaks in subjects from HLNRA when measured at 7 minutes after irradiation (P=0.04). In this pilot study, a low basal damage in elderly subjects from HLNRA and a reduced induction of DNA damage after 2 Gy and 4 Gy irradiation in high dose group subjects from HLNRA might suggest a possible role of chronic low dose natural radiation on the induction of an in vivo radio adaptive response. However, our findings need more validation in a larger study population. (author)

  19. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1993-12-01

    In this project the author has proposed several mechanisms for radiation damage to DNA and its constituents, and has detailed a series of experiments utilizing electron spin resonance spectroscopy, HPLC, GC-mass spectroscopy and ab initio molecular orbital calculations to test the proposed mechanisms. In this years work he has completed several experiments on the role of hydration water on DNA radiation damage, continued the investigation of the localization of the initial charges and their reactions on DNA, investigated protonation reactions in DNA base anions, and employed ab initio molecular orbital theory to gain insight into the initial events of radiation damage to DNA. Ab initio calculations have provided an understanding of the energetics evolved in anion and cation formation, ion radical transfer in DNA as well as proton transfer with DNA base pair radical ions. This has been extended in this years work to a consideration of ionization energies of various components of the DNA deoxyribose backbone and resulting neutral sugar radicals. This information has aided the formation of new radiation models for the effect of radiation on DNA. During this fiscal year four articles have been published, four are in press, one is submitted and several more are in preparation. Four papers have been presented at scientific meetings. This years effort will include another review article on the open-quotes Electron Spin Resonance of Radiation Damage to DNAclose quotes

  20. A single portion of blueberry (Vaccinium corymbosum L) improves protection against DNA damage but not vascular function in healthy male volunteers.

    Science.gov (United States)

    Del Bó, Cristian; Riso, Patrizia; Campolo, Jonica; Møller, Peter; Loft, Steffen; Klimis-Zacas, Dorothy; Brambilla, Ada; Rizzolo, Anna; Porrini, Marisa

    2013-03-01

    It has been suggested that anthocyanin-rich foods may exert antioxidant effects and improve vascular function as demonstrated mainly in vitro and in the animal model. Blueberries are rich sources of anthocyanins and we hypothesized that their intake could improve cell protection against oxidative stress and affect endothelial function in humans. The aim of the study was to investigate the effect of one portion (300 g) of blueberries on selected markers of oxidative stress and antioxidant protection (endogenous and oxidatively induced DNA damage) and of vascular function (changes in peripheral arterial tone and plasma nitric oxide levels) in male subjects. In a randomized cross-over design, separated by a wash out period ten young volunteers received one portion of blueberries ground by blender or one portion of a control jelly. Before and after consumption (at 1, 2, and 24 hours), blood samples were collected and used to evaluate anthocyanin absorption (through mass spectrometry), endogenous and H(2)O(2)-induced DNA damage in blood mononuclear cells (through the comet assay), and plasma nitric oxide concentrations (through a fluorometric assay). Peripheral arterial function was assessed by means of Endo-PAT 2000. Blueberries significantly reduced (P < .01) H(2)O(2)-induced DNA damage (-18%) 1 hour after blueberry consumption compared to control. No significant differences were observed for endogenous DNA damage, peripheral arterial function and nitric oxide levels after blueberry intake. In conclusion, one portion of blueberries seems sufficient to improve cell antioxidant defense against DNA damage, but further studies are necessary to understand their role on vascular function. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Assessment of Radiation-Attenuated Vaccine or Thyme Oil Treatment on Controlling DNA Damage and Nitric Oxide Synthesis in Brain of Rat Infected with Toxocara canis

    International Nuclear Information System (INIS)

    Amin, M.M.; Hafez, E.N.; Abd Raboo, M.A.

    2016-01-01

    Toxocara canis is a worldwide zoonotic roundworm that infects a number of hosts including humans. It exhibits marked affinity to the nervous tissues. This study deals with the changes in the brain of Toxocara canis infected rats regarding parasitological, nitric oxide (NO) level and DNA damage compared to the effect of vaccination with gamma radiation-attenuated embryonated egg or thyme oil treatment. Eighty rats were classified into four groups (twenty each): GI (normal control); GII infected with 2500 T. canis infective eggs/ml/rat (infected control); GIII vaccinated with 800 Gy gamma-attenuated embryonated eggs (vaccinated group) and GIV infected with 2500 T. canis eggs and treated with thyme oil (thyme treated group). At the 14th day post-infection, ten rats from each group were sacrificed and the remaining were re-infected (challenged) with the same number of eggs. At the 14th days post challenge, brain tissues were taken for larval recovery, nitric oxide level evaluation and DNA damage using fragmentation and comet assay. The results exhibited a significant decrease in larval count and nitric oxide level with less damage in brain cells in thyme treated and gamma radiation-attenuated vaccinated groups compared to control infected group. It is also, concluded that vaccination using γ- rays is more effective in protection compared to using thyme oil.

  2. Lactation Affects Isolated Mitochondria and Its Fatty Acid Composition but Has No Effect on Tissue Protein Oxidation, Lipid Peroxidation or DNA-Damage in Laboratory Mice

    Directory of Open Access Journals (Sweden)

    Teresa G. Valencak

    2016-01-01

    Full Text Available Linking peak energy metabolism to lifespan and aging remains a major question especially when focusing on lactation in females. We studied, if and how lactation affects in vitro mitochondrial oxygen consumption and mitochondrial fatty acid composition. In addition, we assessed DNA damage, lipid peroxidation and protein carbonyls to extrapolate on oxidative stress in mothers. As model system we used C57BL/6NCrl mice and exposed lactating females to two ambient temperatures (15 °C and 22 °C while they nursed their offspring until weaning. We found that state II and state IV respiration rates of liver mitochondria were significantly higher in the lactating animals than in non-lactating mice. Fatty acid composition of isolated liver and heart mitochondria differed between lactating and non-lactating mice with higher n-6, and lower n-3 polyunsaturated fatty acids in the lactating females. Surprisingly, lactation did not affect protein carbonyls, lipid peroxidation and DNA damage, nor did moderate cold exposure of 15 °C. We conclude that lactation increases rates of mitochondrial uncoupling and alters mitochondrial fatty acid composition thus supporting the “uncoupling to survive” hypothesis. Regarding oxidative stress, we found no impact of lactation and lower ambient temperature and contribute to growing evidence that there is no linear relationship between oxidative damage and lactation.

  3. Quantification of cell-free DNA in blood plasma and DNA damage degree in lymphocytes to evaluate dysregulation of apoptosis in schizophrenia patients.

    Science.gov (United States)

    Ershova, E S; Jestkova, E M; Chestkov, I V; Porokhovnik, L N; Izevskaya, V L; Kutsev, S I; Veiko, N N; Shmarina, G; Dolgikh, O; Kostyuk, S V

    2017-04-01

    Oxidative DNA damage has been proposed as one of the causes of schizophrenia (SZ), and post mortem data indicate a dysregulation of apoptosis in SZ patients. To evaluate apoptosis in vivo we quantified the concentration of plasma cell-free DNA (cfDNA index, determined using fluorescence), the levels of 8-oxodG in cfDNA (immunoassay) and lymphocytes (FL1-8-oxodG index, flow cytometry) of male patients with acute psychotic disorders: paranoid SZ (total N = 58), schizophreniform (N = 11) and alcohol-induced (N = 14) psychotic disorder, and 30 healthy males. CfDNA in SZ (N = 58) does not change compared with controls. In SZ patients. Elevated levels of 8-oxodG were found in cfDNA (N = 58) and lymphocytes (n = 45). The main sources of cfDNA are dying cells with oxidized DNA. Thus, the cfDNA/FL1-8-oxodG ratio shows the level of apoptosis in damaged cells. Two subgroups were identified among the SZ patients (n = 45). For SZ-1 (31%) and SZ-2 (69%) median values of cfDNA/FL1-8-oxodG index are related as 1:6 (p DNA in the patient's body tissues and may be a contributing cause of acute psychotic disorder. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. SIRT participates at DNA damage response

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Mi Yong; Joeng, Jae Min; Lee, Kee Ho [Korea Cancer Center Hospital, Seoul (Korea, Republic of); Park, Gil Hong [College of Medicine, Korea University, Seoul (Korea, Republic of)

    2009-05-15

    Sir2 maintains genomic stability in multiple ways in yeast. As a NAD{sup +}-dependent histone deacetylase, Sir2 has been reported to control chromatin silencing. In both budding yeast and Drosophila, overexpression of Sir2 extends life span. Previous reports have also demonstrated that Sir2 participate at DNA damage repair. A protein complex containing Sir2 has been reported to translocate to DNA double-strand breaks. Following DNA damage response, SIRT1 deacetylates p53 protein and attenuates its ability as a transcription factor. Consequently, SIRT1 over-expression increases cell survival under DNA damage inducing conditions. These previous observations mean a possibility that signals generated during the process of DNA repair are delivered through SIRT1 to acetylated p53. We present herein functional evidence for the involvement of SIRT1 in DNA repair response to radiation. In addition, this modulation of DNA repair activity may be connected to deacetylation of MRN proteins.

  5. Effect of deregulation of Sonic Hedgehog pathway on responses to DNA damage and cancer predisposition

    International Nuclear Information System (INIS)

    Charazac, Aurelie

    2015-01-01

    The Gorlin syndrome is a rare genetic disorder characterized by several developmental abnormalities. Due to mutations in PTCH1, a key player of the sonic hedgehog signaling pathway, clinical manifestations also includes hyper-radiosensitivity and an increased predisposition to the development of basal cell carcinomas. Given the implication of DNA repair system defects in hyper-radiosensitivity pathologies, we decided to study the effect of PTCH1 mutations on the DNA damage response in order to better understand the cellular and molecular mechanisms leading to Gorlin's phenotype.This study demonstrate a global failure of the DNA damage repair systems in Gorlin fibroblasts with respect to controls. It highlights in particular the collapse of the base excision repair pathway (BER) responsible for the repair of oxidative DNA damage. (author) [fr

  6. Evaluation of DNA damage in patients with arsenic poisoning: urinary 8-hydroxydeoxyguanine

    International Nuclear Information System (INIS)

    Yamauchi, Hiroshi; Aminaka, Yoshito; Yoshida, Katsumi; Sun Guifan; Pi Jingbo; Waalkes, Michael P.

    2004-01-01

    The relationship between arsenic exposure and DNA damage in patients with acute or chronic arsenic poisoning was analyzed. Urinary 8-hydroxydeoxyguanine (8-OHdG) concentrations were measured as an indication of oxidative DNA damage. A remarkable increase in 8-OHdG in the urine was observed in 60% of 52 patients with acute arsenic poisoning from the accidental oral intake of the arsenic trioxide. This was two- to threefold higher than levels in normal healthy subjects (n = 248). There was a clear relationship between arsenic concentrations in urine after acute poisoning and elevated levels of 8-OHdG. Levels of urinary 8-OHdG returned to normal within 180 days after the acute arsenic poisoning event. In patients chronically poisoned by the consumption of well water with elevated levels of arsenate [As(V)], elevated 8-OHdG concentrations in urine were also observed. A significant correlation between the 8-OHdG levels and arsenic levels in the urine was observed in 82 patients with chronic poisoning. Thus, evidence of oxidative DNA damage occurred in acute arsenic poisoning by arsenite [As(III)] and in chronic arsenic poisoning by As(V). In chronic poisoning patients provided low-arsenic drinking water, evidence of DNA damage subsided between 9 months and 1 year after the high levels of arsenic intake were reduced. The initial level of arsenic exposure appeared to dictate the length of this recovery period. These data indicate that some aspects of chronic and acute arsenic poisoning may be reversible with the cessation of exposure. This knowledge may contribute to our understanding of the risk elevation from arsenic carcinogenesis and perhaps be used in a prospective fashion to assess individual risk

  7. Oxidants and not alkylating agents induce rapid mtDNA loss and mitochondrial dysfunction

    Science.gov (United States)

    Furda, Amy M.; Marrangoni, Adele M.; Lokshin, Anna; Van Houten, Bennett

    2013-01-01

    Mitochondrial DNA (mtDNA) is essential for proper mitochondrial function and encodes 22 tRNAs, 2 rRNAs and 13 polypeptides that make up subunits of complex I, III, IV, in the electron transport chain and complex V, the ATP synthase. Although mitochondrial dysfunction has been implicated in processes such as premature aging, neurodegeneration, and cancer, it has not been shown whether persistent mtDNA damage causes a loss of oxidative phosphorylation. We addressed this question by treating mouse embryonic fibroblasts with either hydrogen peroxide (H2O2) or the alkylating agent methyl methanesulfonate (MMS) and measuring several endpoints, including mtDNA damage and repair rates using QPCR, levels of mitochondrial- and nuclear-encoded proteins using antibody analysis, and a pharmacologic profile of mitochondria using the Seahorse Extracellular Flux Analyzer. We show that a 60 min treatment with H2O2 causes persistent mtDNA lesions, mtDNA loss, decreased levels of a nuclear-encoded mitochondrial subunit, a loss of ATP-linked oxidative phosphorylation and a loss of total reserve capacity. Conversely, a 60 min treatment with 2 mM MMS causes persistent mtDNA lesions but no mtDNA loss, no decrease in levels of a nuclear-encoded mitochondrial subunit, and no mitochondrial dysfunction. These results suggest that persistent mtDNA damage is not sufficient to cause mitochondrial dysfunction. PMID:22766155

  8. Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues

    International Nuclear Information System (INIS)

    Curtis, Carol D; Thorngren, Daniel L; Nardulli, Ann M

    2010-01-01

    During the course of normal cellular metabolism, oxygen is consumed and reactive oxygen species (ROS) are produced. If not effectively dissipated, ROS can accumulate and damage resident proteins, lipids, and DNA. Enzymes involved in redox regulation and DNA repair dissipate ROS and repair the resulting damage in order to preserve a functional cellular environment. Because increased ROS accumulation and/or unrepaired DNA damage can lead to initiation and progression of cancer and we had identified a number of oxidative stress and DNA repair proteins that influence estrogen responsiveness of MCF-7 breast cancer cells, it seemed possible that these proteins might be differentially expressed in normal mammary tissue, benign hyperplasia (BH), ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC). Immunohistochemistry was used to examine the expression of a number of oxidative stress proteins, DNA repair proteins, and damage markers in 60 human mammary tissues which were classified as BH, DCIS or IBC. The relative mean intensity was determined for each tissue section and ANOVA was used to detect statistical differences in the relative expression of BH, DCIS and IBC compared to normal mammary tissue. We found that a number of these proteins were overexpressed and that the cellular localization was altered in human breast cancer tissue. Our studies suggest that oxidative stress and DNA repair proteins not only protect normal cells from the damaging effects of ROS, but may also promote survival of mammary tumor cells

  9. DNA damage-induced inflammation and nuclear architecture.

    Science.gov (United States)

    Stratigi, Kalliopi; Chatzidoukaki, Ourania; Garinis, George A

    2017-07-01

    Nuclear architecture and the chromatin state affect most-if not all- DNA-dependent transactions, including the ability of cells to sense DNA lesions and restore damaged DNA back to its native form. Recent evidence points to functional links between DNA damage sensors, DNA repair mechanisms and the innate immune responses. The latter raises the question of how such seemingly disparate processes operate within the intrinsically complex nuclear landscape and the chromatin environment. Here, we discuss how DNA damage-induced immune responses operate within chromatin and the distinct sub-nuclear compartments highlighting their relevance to chronic inflammation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Miscoding and mutagenic properties of 8-oxoguanine and abasic sites: Ubiquitous lesions in damaged DNA

    International Nuclear Information System (INIS)

    Grollman, A.P.; Takeshita, Masaru

    1995-01-01

    More than twenty oxidatively-damaged bases, including 8-oxoguanine, have been found to occur in genomic DNA. Some of these lesions block DNA replication and are potentially lethal; others generate mutations which can initiate carcinogenesis and promote cellular aging. In this report, the authors focus attention on the mutagenicity and repair of 8-oxoguanine. Kasai and Nishimura's discovery that hydroxyl radicals react with guanine residues in DNA to form 8-oxoguanine and the development of sensitive methods for the detection and quantitation of this modified base led to the observation that approximately 1 in 10 5 guanine residues in mammalian DNA are oxidized at the C-8 position. DNA containing 8-oxoguanine and synthetic analogs of the abasic site have been used to investigate the miscoding and mutagenic potential of these ubiquitous lesions. Studies in the laboratory were facilitated by the development of solid state synthetic methods by which these lesions could be introduced at defined positions in DNA. In this paper, the authors review studies in which 8-oxoguanine and abasic sites have been used in model systems to explore various early events in the replication of selectively damaged DNA

  11. UVA activation of N-dialkylnitrosamines releasing nitric oxide, producing strand breaks as well as oxidative damages in DNA, and inducing mutations in the Ames test

    International Nuclear Information System (INIS)

    Arimoto-Kobayashi, Sakae; Sano, Kayoko; Machida, Masaki; Kaji, Keiko; Yakushi, Keiko

    2010-01-01

    We investigated the photo-mutagenicity and photo-genotoxicity of N-dialkylnitrosamines and its mechanisms of UVA activation. With simultaneous irradiation of UVA, photo-mutagenicity of seven N-dialkylnitrosamines was observed in Ames bacteria (Salmonella typhimurium TA1535) in the absence of metabolic activation. Mutagenicity of pre-irradiated N-dialkylnitrosamines was also observed with S. typhimurium hisG46, TA100, TA102 and YG7108 in the absence of metabolic activation. UVA-mediated mutation with N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) decreased by adding either the NO or OH radical scavenger. When superhelical DNA was irradiated with N-dialkylnitrosamines, nicked circular DNA appeared. Ten N-dialkylnitrosamines examined produced strand breaks in the treated DNA in the presence of UVA. The level of single-strand breaks in φX174 DNA mediated by N-nitrosomorpholine (NMOR) and UVA decreased by adding either a radical scavenger or superoxide dismutase. When calf thymus DNA was treated with N-dialkylnitrosamines (NDMA, NDEA, NMOR, N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP)) and UVA, the ratio of 8-oxodG/dG in the DNA increased. Action spectra were obtained to determine if nitrosamine acts as a sensitizer of UVA. Both mutation frequency and NO formation were highest at the absorption maximum of nitrosamines, approximately 340 nm. The plots of NO formation and mutation frequency align with the absorption curve of NPYR, NMOR and NDMA. A significant linear correlation between the optical density of N-dialkynitrosamines at 340 nm and NO formation in each irradiated solution was revealed by ANOVA. We would like to propose the hypothesis that the N-nitroso moiety of N-dialkylnitrosamines absorbs UVA photons, UVA-photolysis of N-dialkylnitrosamines brings release of nitric oxide, and subsequent production of alkyl radical cations and active oxygen species follow as secondary events, which cause DNA strand breaks, oxidative and

  12. UVA activation of N-dialkylnitrosamines releasing nitric oxide, producing strand breaks as well as oxidative damages in DNA, and inducing mutations in the Ames test

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto-Kobayashi, Sakae [Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima, Okayama 700-8530 (Japan); Sano, Kayoko; Machida, Masaki; Kaji, Keiko; Yakushi, Keiko [Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima, Okayama 700-8530 (Japan)

    2010-09-10

    We investigated the photo-mutagenicity and photo-genotoxicity of N-dialkylnitrosamines and its mechanisms of UVA activation. With simultaneous irradiation of UVA, photo-mutagenicity of seven N-dialkylnitrosamines was observed in Ames bacteria (Salmonella typhimurium TA1535) in the absence of metabolic activation. Mutagenicity of pre-irradiated N-dialkylnitrosamines was also observed with S. typhimurium hisG46, TA100, TA102 and YG7108 in the absence of metabolic activation. UVA-mediated mutation with N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) decreased by adding either the NO or OH radical scavenger. When superhelical DNA was irradiated with N-dialkylnitrosamines, nicked circular DNA appeared. Ten N-dialkylnitrosamines examined produced strand breaks in the treated DNA in the presence of UVA. The level of single-strand breaks in {phi}X174 DNA mediated by N-nitrosomorpholine (NMOR) and UVA decreased by adding either a radical scavenger or superoxide dismutase. When calf thymus DNA was treated with N-dialkylnitrosamines (NDMA, NDEA, NMOR, N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP)) and UVA, the ratio of 8-oxodG/dG in the DNA increased. Action spectra were obtained to determine if nitrosamine acts as a sensitizer of UVA. Both mutation frequency and NO formation were highest at the absorption maximum of nitrosamines, approximately 340 nm. The plots of NO formation and mutation frequency align with the absorption curve of NPYR, NMOR and NDMA. A significant linear correlation between the optical density of N-dialkynitrosamines at 340 nm and NO formation in each irradiated solution was revealed by ANOVA. We would like to propose the hypothesis that the N-nitroso moiety of N-dialkylnitrosamines absorbs UVA photons, UVA-photolysis of N-dialkylnitrosamines brings release of nitric oxide, and subsequent production of alkyl radical cations and active oxygen species follow as secondary events, which cause DNA strand breaks, oxidative and

  13. Accelerated repair and reduced mutagenicity of DNA damage induced by cigarette smoke in human bronchial cells transfected with E.coli formamidopyrimidine DNA glycosylase.

    Directory of Open Access Journals (Sweden)

    Mara Foresta

    Full Text Available Cigarette smoke (CS is associated to a number of pathologies including lung cancer. Its mutagenic and carcinogenic effects are partially linked to the presence of reactive oxygen species and polycyclic aromatic hydrocarbons (PAH inducing DNA damage. The bacterial DNA repair enzyme formamidopyrimidine DNA glycosylase (FPG repairs both oxidized bases and different types of bulky DNA adducts. We investigated in vitro whether FPG expression may enhance DNA repair of CS-damaged DNA and counteract the mutagenic effects of CS in human lung cells. NCI-H727 non small cell lung carcinoma cells were transfected with a plasmid vector expressing FPG fused to the Enhanced Green Fluorescent Protein (EGFP. Cells expressing the fusion protein EGFP-FPG displayed accelerated repair of adducts and DNA breaks induced by CS condensate. The mutant frequencies induced by low concentrations of CS condensate to the Na(+K(+-ATPase locus (oua(r were significantly reduced in cells expressing EGFP-FPG. Hence, expression of the bacterial DNA repair protein FPG stably protects human lung cells from the mutagenic effects of CS by improving cells' capacity to repair damaged DNA.

  14. Cellular Responses to Cisplatin-Induced DNA Damage

    Directory of Open Access Journals (Sweden)

    Alakananda Basu

    2010-01-01

    Full Text Available Cisplatin is one of the most effective anticancer agents widely used in the treatment of solid tumors. It is generally considered as a cytotoxic drug which kills cancer cells by damaging DNA and inhibiting DNA synthesis. How cells respond to cisplatin-induced DNA damage plays a critical role in deciding cisplatin sensitivity. Cisplatin-induced DNA damage activates various signaling pathways to prevent or promote cell death. This paper summarizes our current understandings regarding the mechanisms by which cisplatin induces cell death and the bases of cisplatin resistance. We have discussed various steps, including the entry of cisplatin inside cells, DNA repair, drug detoxification, DNA damage response, and regulation of cisplatin-induced apoptosis by protein kinases. An understanding of how various signaling pathways regulate cisplatin-induced cell death should aid in the development of more effective therapeutic strategies for the treatment of cancer.

  15. Role of DNA repair in repair of cytogenetic damages. Slowly repaired DNA injuries involved in cytogenetic damages repair

    International Nuclear Information System (INIS)

    Zaichkina, S.I.; Rozanova, O.M.; Aptikaev, G.F.; Ganassi, E.Eh.

    1989-01-01

    Caffeine was used to study the kinetics of cytogenetic damages repair in Chinese hamster fibroblasts. Its half-time (90 min) was shown to correlate with that of repair of slowly repaired DNA damages. The caffeine-induced increase in the number of irreparable DNA damages, attributed to inhibition of double-strand break repair, is in a quantitative correlation with the effect of the cytogenetic damage modification

  16. Inflammation, gene mutation and photoimmunosuppression in response to UVR-induced oxidative damage contributes to photocarcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, Gary M. [Dermatology Research Laboratories, Division of Medicine, Melanoma and Skin Cancer Research Institute, Royal Prince Alfred Hospital at the University of Sydney, Sydney, NSW (Australia)]. E-mail: garyh@med.usyd.edu.au

    2005-04-01

    Ultraviolet (UV) radiation causes inflammation, gene mutation and immunosuppression in the skin. These biological changes are responsible for photocarcinogenesis. UV radiation in sunlight is divided into two wavebands, UVB and UVA, both of which contribute to these biological changes, and therefore probably to skin cancer in humans and animal models. Oxidative damage caused by UV contributes to inflammation, gene mutation and immunosuppression. This article reviews evidence for the hypothesis that UV oxidative damage to these processes contributes to photocarcinogenesis. UVA makes a larger impact on oxidative stress in the skin than UVB by inducing reactive oxygen and nitrogen species which damage DNA, protein and lipids and which also lead to NAD+ depletion, and therefore energy loss from the cell. Lipid peroxidation induces prostaglandin production that in association with UV-induced nitric oxide production causes inflammation. Inflammation drives benign human solar keratosis (SK) to undergo malignant conversion into squamous cell carcinoma (SCC) probably because the inflammatory cells produce reactive oxygen species, thus increasing oxidative damage to DNA and the immune system. Reactive oxygen or nitrogen appears to cause the increase in mutational burden as SK progress into SCC in humans. UVA is particularly important in causing immunosuppression in both humans and mice, and UV lipid peroxidation induced prostaglandin production and UV activation of nitric oxide synthase is important mediators of this event. Other immunosuppressive events are likely to be initiated by UV oxidative stress. Antioxidants have also been shown to reduce photocarcinogenesis. While most of this evidence comes from studies in mice, there is supporting evidence in humans that UV-induced oxidative damage contributes to inflammation, gene mutation and immunosuppression. Available evidence implicates oxidative damage as an important contributor to sunlight-induced carcinogenesis in humans.

  17. Inflammation, gene mutation and photoimmunosuppression in response to UVR-induced oxidative damage contributes to photocarcinogenesis

    International Nuclear Information System (INIS)

    Halliday, Gary M.

    2005-01-01

    Ultraviolet (UV) radiation causes inflammation, gene mutation and immunosuppression in the skin. These biological changes are responsible for photocarcinogenesis. UV radiation in sunlight is divided into two wavebands, UVB and UVA, both of which contribute to these biological changes, and therefore probably to skin cancer in humans and animal models. Oxidative damage caused by UV contributes to inflammation, gene mutation and immunosuppression. This article reviews evidence for the hypothesis that UV oxidative damage to these processes contributes to photocarcinogenesis. UVA makes a larger impact on oxidative stress in the skin than UVB by inducing reactive oxygen and nitrogen species which damage DNA, protein and lipids and which also lead to NAD+ depletion, and therefore energy loss from the cell. Lipid peroxidation induces prostaglandin production that in association with UV-induced nitric oxide production causes inflammation. Inflammation drives benign human solar keratosis (SK) to undergo malignant conversion into squamous cell carcinoma (SCC) probably because the inflammatory cells produce reactive oxygen species, thus increasing oxidative damage to DNA and the immune system. Reactive oxygen or nitrogen appears to cause the increase in mutational burden as SK progress into SCC in humans. UVA is particularly important in causing immunosuppression in both humans and mice, and UV lipid peroxidation induced prostaglandin production and UV activation of nitric oxide synthase is important mediators of this event. Other immunosuppressive events are likely to be initiated by UV oxidative stress. Antioxidants have also been shown to reduce photocarcinogenesis. While most of this evidence comes from studies in mice, there is supporting evidence in humans that UV-induced oxidative damage contributes to inflammation, gene mutation and immunosuppression. Available evidence implicates oxidative damage as an important contributor to sunlight-induced carcinogenesis in humans

  18. DNA damage in lung after oral exposure to diesel exhaust particles in Big Blue (R) rats

    DEFF Research Database (Denmark)

    Müller, Anne Kirstine; Farombi, E.O.; Møller, P.

    2004-01-01

    Several chemical mutagens and carcinogens, including polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs, are adsorbed to the surface of diesel exhaust particles (DEP). DEP can induce formation of reactive oxygen species and cause oxidative DNA damage as well as bulky carcinogen DNA adducts....... Lung tissue is a target organ for DEP induced cancer following inhalation. Recent studies have provided evidence that the lung is also a target organ for DNA damage and cancer after oral exposure to other complex mixtures of PAHs. The genotoxic effect of oral administration of DEP was investigated...

  19. DNA damage in the oligodendrocyte lineage and its role in brain aging.

    Science.gov (United States)

    Tse, Kai-Hei; Herrup, Karl

    2017-01-01

    Myelination is a recent evolutionary addition that significantly enhances the speed of transmission in the neural network. Even slight defects in myelin integrity impair performance and enhance the risk of neurological disorders. Indeed, myelin degeneration is an early and well-recognized neuropathology that is age associated, but appears before cognitive decline. Myelin is only formed by fully differentiated oligodendrocytes, but the entire oligodendrocyte lineage are clear targets of the altered chemistry of the aging brain. As in neurons, unrepaired DNA damage accumulates in the postmitotic oligodendrocyte genome during normal aging, and indeed may be one of the upstream causes of cellular aging - a fact well illustrated by myelin co-morbidity in premature aging syndromes arising from deficits in DNA repair enzymes. The clinical and experimental evidence from Alzheimer's disease, progeroid syndromes, ataxia-telangiectasia and other conditions strongly suggest that oligodendrocytes may in fact be uniquely vulnerable to oxidative DNA damage. If this damage remains unrepaired, as is increasingly true in the aging brain, myelin gene transcription and oligodendrocyte differentiation is impaired. Delineating the relationships between early myelin loss and DNA damage in brain aging will offer an additional dimension outside the neurocentric view of neurodegenerative disease. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Role of DNA repair in repair of cytogenetic damages. Contribution of repair of single-strand DNA breaks to cytogenetic damages repair

    International Nuclear Information System (INIS)

    Rozanova, O.M.; Zaichkina, S.I.; Aptikaev, G.F.; Ganassi, E.Eh.

    1989-01-01

    The comparison was made between the results of the effect of poly(ADP-ribosylation) ingibitors (e.g. nicotinamide and 3-aminobenzamide) and a chromatin proteinase ingibitor, phenylmethylsulfonylfluoride, on the cytogenetic damages repair, by a micronuclear test, and DNA repair in Chinese hamster fibroblasts. The values of the repair half-periods (5-7 min for the cytogenetic damages and 5 min for the rapidly repaired DNA damages) and a similar modyfying effect with regard to radiation cytogenetic damages and kynetics of DNA damages repair were found to be close. This confirms the contribution of repair of DNA single-strand breaks in the initiation of structural damages to chromosomes

  1. Transcription and DNA Damage: Holding Hands or Crossing Swords?

    Science.gov (United States)

    D'Alessandro, Giuseppina; d'Adda di Fagagna, Fabrizio

    2017-10-27

    Transcription has classically been considered a potential threat to genome integrity. Collision between transcription and DNA replication machinery, and retention of DNA:RNA hybrids, may result in genome instability. On the other hand, it has been proposed that active genes repair faster and preferentially via homologous recombination. Moreover, while canonical transcription is inhibited in the proximity of DNA double-strand breaks, a growing body of evidence supports active non-canonical transcription at DNA damage sites. Small non-coding RNAs accumulate at DNA double-strand break sites in mammals and other organisms, and are involved in DNA damage signaling and repair. Furthermore, RNA binding proteins are recruited to DNA damage sites and participate in the DNA damage response. Here, we discuss the impact of transcription on genome stability, the role of RNA binding proteins at DNA damage sites, and the function of small non-coding RNAs generated upon damage in the signaling and repair of DNA lesions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Mechanisms for radiation damage in DNA

    International Nuclear Information System (INIS)

    Sevilla, M.D.

    1985-07-01

    Radiation damage to DNA results from the direct interaction of radiation with DNA where positive ions, electrons and excited states are formed in the DNA, and the indirect effect where radical species formed in the surrounding medium by the radiation attack the DNA. The primary mechanism proposed for radiation damage, by the direct effect, is that positive and negative ions formed within the DNA strand migrate through the stacked DNA bases. The ions can then recombine, react with the DNA bases most likely to react by protonation of the anion and deprotonation or hydroxylation of the cation or transfer out of the DNA chain to the surrounding histone protein. This work as aimed at understanding the possible reactions of the DNA base ion radicals, as well as their initial distribution in the DNA strand. 31 refs

  3. Lung Oxidative Stress, DNA Damage, Apoptosis, and Fibrosis in Adenine-Induced Chronic Kidney Disease in Mice

    Directory of Open Access Journals (Sweden)

    Abderrahim Nemmar

    2017-11-01

    Full Text Available It is well-established that there is a crosstalk between the lung and the kidney, and several studies have reported association between chronic kidney disease (CKD and pulmonary pathophysiological changes. Experimentally, CKD can be caused in mice by dietary intake of adenine. Nevertheless, the consequence of such intervention on the lung received only scant attention. Here, we assessed the pulmonary effects of adenine (0.2% w/w in feed for 4 weeks-induced CKD in mice by assessing various physiological histological and biochemical endpoints. Adenine treatment induced a significant increase in urine output, urea and creatinine concentrations, and it decreased the body weight and creatinine clearance. It also increased proteinuria and the urinary levels of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin. Compared with control group, the histopathological evaluation of lungs from adenine-treated mice showed polymorphonuclear leukocytes infiltration in alveolar and bronchial walls, injury, and fibrosis. Moreover, adenine caused a significant increase in lung lipid peroxidation and reactive oxygen species and decreased the antioxidant catalase. Adenine also induced DNA damage assessed by COMET assay. Similarly, adenine caused apoptosis in the lung characterized by a significant increase of cleaved caspase-3. Moreover, adenine induced a significant increase in the expression of nuclear factor erythroid 2–related factor 2 (Nrf2 in the lung. We conclude that administration of adenine in mice induced CKD is accompanied by lung oxidative stress, DNA damage, apoptosis, and Nrf2 expression and fibrosis.

  4. Metabolic activation of polycyclic and heterocyclic aromatic hydrocarbons and DNA damage: A review

    International Nuclear Information System (INIS)

    Xue Weiling; Warshawsky, David

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic compounds (HACs) constitute a major class of chemical carcinogens present in the environment. These compounds require activation to electrophilic metabolites to exert their mutagenic or carcinogenic effects. There are three principal pathways currently proposed for metabolic activation of PAH and HAC: the pathway via bay region dihydrodiol epoxide by cytochrome P450 enzymes (CYPs), the pathway via radical cation by one-electron oxidation, and the ortho-quinone pathway by dihydrodiol dehydrogenase (DD). In addition to these major pathways, a brief description of a minor metabolic activation pathway, sulfonation, for PAHs that contain a primary benzylic alcoholic group or secondary hydroxyl group(s) is included in this review. The DNA damages caused through the reactive metabolites of PAH/HAC are described involving the DNA covalent binding to form stable or depurinating adducts, the formation of apurinic sites, and the oxidative damage. The review emphasizes the chemical/biochemical reactions involved in the metabolic processes and the chemical structures of metabolites and DNA adducts

  5. Application of the CometChip platform to assess DNA damage in field-collected blood samples from turtles.

    Science.gov (United States)

    Sykora, Peter; Chiari, Ylenia; Heaton, Andrew; Moreno, Nickolas; Glaberman, Scott; Sobol, Robert W

    2018-05-01

    DNA damage has been linked to genomic instability and the progressive breakdown of cellular and organismal homeostasis, leading to the onset of disease and reduced longevity. Insults to DNA from endogenous sources include base deamination, base hydrolysis, base alkylation, and metabolism-induced oxidative damage that can lead to single-strand and double-strand DNA breaks. Alternatively, exposure to environmental pollutants, radiation or ultra-violet light, can also contribute to exogenously derived DNA damage. We previously validated a novel, high through-put approach to measure levels of DNA damage in cultured mammalian cells. This new CometChip Platform builds on the classical single cell gel electrophoresis or comet methodology used extensively in environmental toxicology and molecular biology. We asked whether the CometChip Platform could be used to measure DNA damage in samples derived from environmental field studies. To this end, we determined that nucleated erythrocytes from multiple species of turtle could be successfully evaluated in the CometChip Platform to quantify levels of DNA damage. In total, we compared levels of DNA damage in 40 animals from two species: the box turtle (Terrapene carolina) and the red-eared slider (Trachemys scripta elegans). Endogenous levels of DNA damage were identical between the two species, yet we did discover some sex-linked differences and changes in DNA damage accumulation. Based on these results, we confirm that the CometChip Platform allows for the measurement of DNA damage in a large number of samples quickly and accurately, and is particularly adaptable to environmental studies using field-collected samples. Environ. Mol. Mutagen. 59:322-333, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  6. Urinary excretion of biomarkers of oxidatively damaged DNA and RNA in hereditary hemochromatosis

    DEFF Research Database (Denmark)

    Broedbaek, Kasper; Poulsen, Henrik E; Weimann, Allan

    2009-01-01

    Oxidatively generated damage to nucleic acids is considered to play a significant role in carcinogenesis, and it has been shown that people with hereditary hemochromatosis are at increased risk of cancer. In this study we used a new refined liquid chromatography-tandem mass spectrometry method...... of the iron overload seen in this disease. By this mechanism cellular damage resulting in end organ damage, typically seen in the liver of such patients, may be mediated....

  7. Ultrafine titanium dioxide particles in the absence of photoactivation can induce oxidative damage to human bronchial epithelial cells

    International Nuclear Information System (INIS)

    Gurr, J.-R.; Wang, Alexander S.S.; Chen, C.-H.; Jan, K.-Y.

    2005-01-01

    Ultrafine titanium dioxide (TiO 2 ) particles have been shown to exhibit strong cytotoxicity when exposed to UVA radiation, but are regarded as a biocompatible material in the absence of photoactivation. In contrast to this concept, the present results indicate that anatase-sized (10 and 20 nm) TiO 2 particles in the absence of photoactivation induced oxidative DNA damage, lipid peroxidation, and micronuclei formation, and increased hydrogen peroxide and nitric oxide production in BEAS-2B cells, a human bronchial epithelial cell line. However, the treatment with anatase-sized (200 and >200 nm) particles did not induce oxidative stress in the absence of light irradiation; it seems that the smaller the particle, the easier it is for the particle to induce oxidative damage. The photocatalytic activity of the anatase form of TiO 2 was reported to be higher than that of the rutile form. In contrast to this notion, the present results indicate that rutile-sized 200 nm particles induced hydrogen peroxide and oxidative DNA damage in the absence of light but the anatase-sized 200 nm particles did not. In total darkness, a slightly higher level of oxidative DNA damage was also detected with treatment using an anatase-rutile mixture than with treatment using either the anatase or rutile forms alone. These results suggest that intratracheal instillation of ultrafine TiO 2 particles may cause an inflammatory response

  8. DNA damage and oxidative stress induced by imidacloprid exposure in the earthworm Eisenia fetida.

    Science.gov (United States)

    Wang, Juan; Wang, Jinhua; Wang, Guangchi; Zhu, Lusheng; Wang, Jun

    2016-02-01

    To investigate the soil ecological effect of imidacloprid, earthworm Eisenia fetida was exposed to various concentrations of imidacloprid (0.10, 0.50, and 1.00 mg kg(-1) soil) respectively after 7, 14, 21, and 28 d. The effect of imidacloprid on reactive oxygen species (ROS) generation, antioxidant enzymes activity [superoxide dismutase (SOD) and catalase (CAT), glutathione S-transferase enzyme (GST)], malondialdehyde (MDA) content and DNA damage of the E. fetida was investigated. Significant increase of the ROS level was observed. The SOD and GST activity were significantly induced at most exposure intervals. CAT activity was inhibited and reflected a dose-dependent relationship on days 7, 14 and 21. High MDA levels were observed and the olive tail moment (OTM) as well as the percentage of DNA in the comet tail (tail DNA%) in comet assay declined with increasing concentrations and exposure time after 7 d. Our results suggested that the sub-chronic exposure of imidacloprid caused DNA damage and lipid peroxidation (LPO) leading to antioxidant responses in earthworm E. fetida. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. DNA Damage Signals and Space Radiation Risk

    Science.gov (United States)

    Cucinotta, Francis A.

    2011-01-01

    Space radiation is comprised of high-energy and charge (HZE) nuclei and protons. The initial DNA damage from HZE nuclei is qualitatively different from X-rays or gamma rays due to the clustering of damage sites which increases their complexity. Clustering of DNA damage occurs on several scales. First there is clustering of single strand breaks (SSB), double strand breaks (DSB), and base damage within a few to several hundred base pairs (bp). A second form of damage clustering occurs on the scale of a few kbp where several DSB?s may be induced by single HZE nuclei. These forms of damage clusters do not occur at low to moderate doses of X-rays or gamma rays thus presenting new challenges to DNA repair systems. We review current knowledge of differences that occur in DNA repair pathways for different types of radiation and possible relationships to mutations, chromosomal aberrations and cancer risks.

  10. Oxidation of DNA, proteins and lipids by DOPA, protein-bound DOPA, and related catechol(amine)s

    DEFF Research Database (Denmark)

    Pattison, David I; Dean, Roger T; Davies, Michael Jonathan

    2002-01-01

    Incubation of free 3,4-dihydroxyphenylalanine (DOPA), protein-bound DOPA (PB-DOPA) and related catechols with DNA, proteins and lipids has been shown to result in oxidative damage to the target molecule. This article reviews these reactions with particular emphasis on those that occur in the pres......Incubation of free 3,4-dihydroxyphenylalanine (DOPA), protein-bound DOPA (PB-DOPA) and related catechols with DNA, proteins and lipids has been shown to result in oxidative damage to the target molecule. This article reviews these reactions with particular emphasis on those that occur...... in the presence of molecular O(2) and redox-active metal ions (e.g. Fe(3+), Cu(2+), Cr(6+)), which are known to increase the rate of DOPA oxidation. The majority of oxidative damage appears to be mediated by reactive oxygen species (ROS) such as superoxide and HO(.) radicals, though other DOPA oxidation products...

  11. DNA Damage by Ionizing Radiation: Tandem Double Lesions by Charged Particles

    Science.gov (United States)

    Huo, Winifred M.; Chaban, Galina M.; Wang, Dunyou; Dateo, Christopher E.

    2005-01-01

    Oxidative damages by ionizing radiation are the source of radiation-induced carcinogenesis, damage to the central nervous system, lowering of the immune response, as well as other radiation-induced damages to human health. Monte Carlo track simulations and kinetic modeling of radiation damages to the DNA employ available molecular and cellular data to simulate the biological effect of high and low LET radiation io the DNA. While the simulations predict single and double strand breaks and base damages, so far all complex lesions are the result of stochastic coincidence from independent processes. Tandem double lesions have not yet been taken into account. Unlike the standard double lesions that are produced by two separate attacks by charged particles or radicals, tandem double lesions are produced by one single attack. The standard double lesions dominate at the high dosage regime. On the other hand, tandem double lesions do not depend on stochastic coincidences and become important at the low dosage regime of particular interest to NASA. Tandem double lesions by hydroxyl radical attack of guanine in isolated DNA have been reported at a dosage of radiation as low as 10 Gy. The formation of two tandem base lesions was found to be linear with the applied doses, a characteristic of tandem lesions. However, tandem double lesions from attack by a charged particle have not been reported.

  12. A study to evaluate the effect of nootropic drug-piracetam on DNA damage in leukocytes and macrophages.

    Science.gov (United States)

    Singh, Sarika; Goswami, Poonam; Swarnkar, Supriya; Singh, Sheelendra Pratap; Wahajuddin; Nath, Chandishwar; Sharma, Sharad

    2011-11-27

    Piracetam is a nootropic drug that protects neurons in neuropathological and age-related diseases and the activation and modulation of peripheral blood cells in patients with neuropathological conditions is well known. Therefore, in the present study, in vivo, ex vivo, and in vitro tests were conducted to investigate the effect of piracetam on leukocytes and macrophages. Lipopolysaccharide (LPS) causes oxidative DNA damage; thus, in the present study, LPS was used as a tool to induce DNA damage. In vivo experiments were conducted on Sprague Dawley rats, and piracetam (600mg/kg, oral) was provided for five consecutive days. On the fifth day, a single injection of LPS (10mg/kg, i.p.) was administered. Three hours after LPS injection, blood leukocytes and peritoneal macrophages were collected and processed, and a variety of different assays were conducted. Ex vivo treatments were performed on isolated rat blood leukocytes, and in vitro experiments were conducted on rat macrophage cell line J774A.1. Cell viability and the level of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and DNA damage were estimated in untreated (control) and piracetam-, LPS- and LPS+piracetam-treated leukocytes and macrophages. In vivo experiments revealed that rats pretreated with piracetam were significantly protected against LPS-induced increases in ROS levels and DNA damage. Ex vivo isolated leukocytes and J774A.1 cells treated with LPS exhibited augmented ROS levels and DNA damage, which were attenuated with piracetam treatment. Thus, the present study revealed the salutary effect of piracetam against LPS-induced oxidative stress and DNA damage in leukocytes and macrophages. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Comparison between micro- and nanosized copper oxide and water soluble copper chloride: interrelationship between intracellular copper concentrations, oxidative stress and DNA damage response in human lung cells.

    Science.gov (United States)

    Strauch, Bettina Maria; Niemand, Rebecca Katharina; Winkelbeiner, Nicola Lisa; Hartwig, Andrea

    2017-08-01

    Nano- and microscale copper oxide particles (CuO NP, CuO MP) are applied for manifold purposes, enhancing exposure and thus the potential risk of adverse health effects. Based on the pronounced in vitro cytotoxicity of CuO NP, systematic investigations on the mode of action are required. Therefore, the impact of CuO NP, CuO MP and CuCl 2 on the DNA damage response on transcriptional level was investigated by quantitative gene expression profiling via high-throughput RT-qPCR. Cytotoxicity, copper uptake and the impact on the oxidative stress response, cell cycle regulation and apoptosis were further analysed on the functional level. Cytotoxicity of CuO NP was more pronounced when compared to CuO MP and CuCl 2 in human bronchial epithelial BEAS-2B cells. Uptake studies revealed an intracellular copper overload in the soluble fractions of both cytoplasm and nucleus, reaching up to millimolar concentrations in case of CuO NP and considerably lower levels in case of CuO MP and CuCl 2 . Moreover, CuCl 2 caused copper accumulation in the nucleus only at cytotoxic concentrations. Gene expression analysis in BEAS-2B and A549 cells revealed a strong induction of uptake-related metallothionein genes, oxidative stress-sensitive and pro-inflammatory genes, anti-oxidative defense-associated genes as well as those coding for the cell cycle inhibitor p21 and the pro-apoptotic Noxa and DR5. While DNA damage inducible genes were activated, genes coding for distinct DNA repair factors were down-regulated. Modulation of gene expression was most pronounced in case of CuO NP as compared to CuO MP and CuCl 2 and more distinct in BEAS-2B cells. GSH depletion and activation of Nrf2 in HeLa S3 cells confirmed oxidative stress induction, mainly restricted to CuO NP. Also, cell cycle arrest and apoptosis induction were most distinct for CuO NP. The high cytotoxicity and marked impact on gene expression by CuO NP can be ascribed to the strong intracellular copper ion release, with subsequent

  14. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  15. Differential effects of silver nanoparticles on DNA damage and DNA repair gene expression in Ogg1-deficient and wild type mice.

    Science.gov (United States)

    Nallanthighal, Sameera; Chan, Cadia; Murray, Thomas M; Mosier, Aaron P; Cady, Nathaniel C; Reliene, Ramune

    2017-10-01

    Due to extensive use in consumer goods, it is important to understand the genotoxicity of silver nanoparticles (AgNPs) and identify susceptible populations. 8-Oxoguanine DNA glycosylase 1 (OGG1) excises 8-oxo-7,8-dihydro-2-deoxyguanine (8-oxoG), a pro-mutagenic lesion induced by oxidative stress. To understand whether defects in OGG1 is a possible genetic factor increasing an individual's susceptibly to AgNPs, we determined DNA damage, genome rearrangements, and expression of DNA repair genes in Ogg1-deficient and wild type mice exposed orally to 4 mg/kg of citrate-coated AgNPs over a period of 7 d. DNA damage was examined at 3 and 7 d of exposure and 7 and 14 d post-exposure. AgNPs induced 8-oxoG, double strand breaks (DSBs), chromosomal damage, and DNA deletions in both genotypes. However, 8-oxoG was induced earlier in Ogg1-deficient mice and 8-oxoG levels were higher after 7-d treatment and persisted longer after exposure termination. AgNPs downregulated DNA glycosylases Ogg1, Neil1, and Neil2 in wild type mice, but upregulated Myh, Neil1, and Neil2 glycosylases in Ogg1-deficient mice. Neil1 and Neil2 can repair 8-oxoG. Thus, AgNP-mediated downregulation of DNA glycosylases in wild type mice may contribute to genotoxicity, while upregulation thereof in Ogg1-deficient mice could serve as an adaptive response to AgNP-induced DNA damage. However, our data show that Ogg1 is indispensable for the efficient repair of AgNP-induced damage. In summary, citrate-coated AgNPs are genotoxic in both genotypes and Ogg1 deficiency exacerbates the effect. These data suggest that humans with genetic polymorphisms and mutations in OGG1 may have increased susceptibility to AgNP-mediated DNA damage.

  16. Roles of diet, lifetime physical activity and oxidative DNA damage in the occurrence of prostate cancer among men in Klang Valley, Malaysia.

    Science.gov (United States)

    Shahar, Suzana; Shafurah, Siti; Hasan Shaari, Nur Suraiya Abu; Rajikan, Roslee; Rajab, Nor Fadilah; Golkhalkhali, Babak; Zainuddin, Zulkifli Md

    2011-01-01

    There is a paucity of information on risk factors of prostate cancer, especially those related to dietary and lifestyle among Asian populations. This study aimed to determine the relationship between dietary intake (macronutrients, fruits, vegetables and lycopene), lifetime physical activity and oxidative DNA damage with prostate cancer. A case control study was carried out among 105 subjects (case n=35, control n=70), matched for age and ethnicity. Data on sociodemographic, medical, dietary intake, consumption of lycopene rich food and lifetime physical activity were obtained through an interview based questionnaire. Anthropometric measurements including weight, height and waist hip circumferences were also carried out on subjects. A total of 3 mL fasting venous blood was drawn to assess lymphocyte oxidative DNA damage using the alkaline comet assay. Cases had a significantly higher intake of fat (27.7 ± 5.5%) as compared to controls (25.1 ± 5.9%) (p diet, high intake of fruits, vegetables and lycopene rich foods and being physical active at middle age were found to be protective. Thus, it is essential for Malaysian men to consume adequate fruits and vegetables, reduce fat intake and engage in physical activity in order to reduce prostate cancer risk.

  17. 32P-labeling test for DNA damage

    International Nuclear Information System (INIS)

    Randerath, K.; Reddy, M.V.; Gupta, R.C.

    1981-01-01

    Covalent adducts formed by the reaction of DNA with chemical carcinogens and mutagens may be detected by a 32 P-labeling test. DNA preparations exposed to chemicals known to bind covalently to DNA [N-methyl-N-nitrosourea, dimethyl sulfate, formaldehyde, β-propiolactone, propylene oxide, streptozotocin, nitrogen mustard, and 1,3-bis(2-chloroethyl)-1-nitrosourea] were digested to a mixture of deoxynucleoside 3'-monophosphates by incubation with micrococcal endonuclease (EC 3.1.31.1) and spleen exonuclease (EC 3.1.16.1). The digests were treated with [γ- 32 P]ATP and T4 polynucleotide kinase (ATP:5'-dephosphopolynucleotide 5'-phosphotransferase, EC 2.7.1.78) to convert the monophosphates to 5'- 32 P-labeled deoxynucleoside 3',5'-bis-phosphates. These compounds were then separated on polyethyl-eneimine-cellulose thin layers in ammonium formate and ammonium sulfate solutions. Autoradiograms of the chromatograms obtained by this high-resolution procedure showed the presence of nucleotides derived from chemically altered, as well as normal, DNA constituents. Maps from DNA exposed to any of the chemicals used exhibited a spot pattern typical for the particular chemical. This method detected a single adduct in 10 5 DNA nucleotides without requiring that the compound under investigation be radioactive and thus provides a useful test to screen chemicals for their capacity to damage DNA by covalent binding

  18. Effect of fenofibrate on oxidative DNA damage and on gene expression related to cell proliferation and apoptosis in rats.

    Science.gov (United States)

    Nishimura, Jihei; Dewa, Yasuaki; Muguruma, Masako; Kuroiwa, Yuichi; Yasuno, Hiroaki; Shima, Tomomi; Jin, Mailan; Takahashi, Miwa; Umemura, Takashi; Mitsumori, Kunitoshi

    2007-05-01

    To investigate the relationship between fenofibrate (FF) and oxidative stress, enzymatic, histopathological, and molecular biological analyses were performed in the liver of male F344 rats fed 2 doses of FF (Experiment 1; 0 and 6000 ppm) for 3 weeks and 3 doses (Experiment 2; 0, 3000, and 6000 ppm) for 9 weeks. FF treatment increased the activity of enzymes such as carnitine acetyltransferase, carnitine palmitoyltransferase, fatty acyl-CoA oxidizing system, and catalase in the liver. However, it decreased those of superoxide dismutase in the liver in both experiments. Increased 8-hydroxy-2'-deoxyguanosine levels in liver DNA and lipofuscin accumulation were observed in the treated rats of Experiment 2. In vitro measurement of reactive oxygen species (ROS) in rat liver microsomes revealed a dose-dependent increase due to FF treatment. Microarray (only Experiment 1) or real-time reverse transcription-polymerase chain reaction analyses revealed that the expression levels of metabolism and DNA repair-related genes such as Aco, Cyp4a1, Cat, Yc2, Gpx2, Apex1, Xrcc5, Mgmt, Mlh1, Gadd45a, and Nbn were increased in FF-treated rats. These results provide evidence of a direct or indirect relationship between oxidative stress and FF treatment. In addition, increases in the expression levels of cell cycle-related genes such as Chek1, Cdc25a, and Ccdn1; increases in the expression levels of cell proliferation-related genes such as Hdgfrp3 and Vegfb; and fluctuations in the expression levels of apoptosis-related genes such as Casp11 and Trp53inp1 were observed in these rats. This suggests that cell proliferation induction, apoptosis suppression, and DNA damage due to oxidative stresses are probably involved in the mechanism of hepatocarcinogenesis due to FF in rats.

  19. DNA damage in grasshopper Chorthippus brunneus (Orthoptera) hatchlings following paraquat exposure.

    Science.gov (United States)

    Augustyniak, M; Nocoń, Ł; Kędziorski, A; Łaszczyca, P; Sawczyn, T; Tarnawska, M; Zawisza-Raszka, A

    2015-04-01

    Comet assay was applied to study genotoxic damage induced by paraquat (PQ) in brain cells of Chorthippus brunneus (Insecta: Orthoptera) hatchlings. Percentage of the comet fluorescence in the tail (TDNA), length of the comet tail (TL) and Olive tail moment (OTM) were used for quantitative assessment of the DNA damage. Multiple regression analysis supplemented standard statistical elaboration of the results. Increasing PQ concentrations applied either directly to the brain cells suspension (10, 50, and 250 μM PQ final concentration--in vitro protocol) or indirectly (50, 250, and 1250 μM PQ final concentration--in vivo protocol) provoked significant increase of oxidative damage to DNA (higher median TDNA and OTM values). The damage increased with time of exposure (0, 5, 15, and 30 min) following in vitro application, but decreased in longer interval (3 vs 24 h) after in vivo administration of paraquat. On contrary, median TL values did not correlate with paraquat concentration irrespectively of the exposure protocol. Possible reason of this discrepancy in light of paraquat toxicity is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Cellular radiosensitivity and DNA damage in primary human fibroblasts

    International Nuclear Information System (INIS)

    Wurm, R.; Burnet, N.G.; Duggal, N.

    1994-01-01

    To evaluate the relationship between radiation-induced cell survival and DNA damage in primary human fibroblasts to decide whether the initial or residual DNA damage levels are more predictive of normal tissue cellular radiosensitivity. Five primary human nonsyndromic and two primary ataxia telangiectasia fibroblast strains grown in monolayer were studied. Cell survival was assessed by clonogenic assay. Irradiation was given at high dose rate (HDR) 1-2 Gy/min. DNA damage was measured in stationary phase cells and expressed as fraction released from the well by pulsed-field gel electrophoresis (PFGE). For initial damage, cells were embedded in agarose and irradiated at HDR on ice. Residual DNA damage was measured in monolayer by allowing a 4-h repair period after HDR irradiation. Following HDR irradiation, cell survival varied between SF 2 0.025 to 0.23. Measurement of initial DNA damage demonstrated linear induction up to 30 Gy, with small differences in the slope of the dose-response curve between strains. No correlation between cell survival and initial damage was found. Residual damage increased linearly up to 80 Gy with a variation in slope by a factor of 3.2. Cell survival correlated with the slope of the dose-response curves for residual damage of the different strains (p = 0.003). The relationship between radiation-induced cell survival and DNA damage in primary human fibroblasts of differing radiosensitivity is closest with the amount of DNA damage remaining after repair. If assays of DNA damage are to be used as predictors of normal tissue response to radiation, residual DNA damage provides the most likely correlation with cell survival. 52 refs., 5 figs., 2 tabs

  1. Mechanisms of dealing with DNA damage in terminally differentiated cells

    Energy Technology Data Exchange (ETDEWEB)

    Fortini, P. [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Rome (Italy); Dogliotti, E., E-mail: eugenia.dogliotti@iss.it [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Rome (Italy)

    2010-03-01

    To protect genomic integrity living cells that are continuously exposed to DNA-damaging insults are equipped with an efficient defence mechanism termed the DNA damage response. Its function is to eliminate DNA damage through DNA repair and to remove damaged cells by apoptosis. The DNA damage response has been investigated mainly in proliferating cells, in which the cell cycle machinery is integrated with the DNA damage signalling. The current knowledge of the mechanisms of DNA repair, DNA damage signalling and cell death of post-mitotic cells that have undergone irreversible cell cycle withdrawal will be reviewed. Evidence will be provided that the protection of the genome integrity in terminally differentiated cells is achieved by different strategies than in proliferating cells.

  2. Mechanisms of dealing with DNA damage in terminally differentiated cells

    International Nuclear Information System (INIS)

    Fortini, P.; Dogliotti, E.

    2010-01-01

    To protect genomic integrity living cells that are continuously exposed to DNA-damaging insults are equipped with an efficient defence mechanism termed the DNA damage response. Its function is to eliminate DNA damage through DNA repair and to remove damaged cells by apoptosis. The DNA damage response has been investigated mainly in proliferating cells, in which the cell cycle machinery is integrated with the DNA damage signalling. The current knowledge of the mechanisms of DNA repair, DNA damage signalling and cell death of post-mitotic cells that have undergone irreversible cell cycle withdrawal will be reviewed. Evidence will be provided that the protection of the genome integrity in terminally differentiated cells is achieved by different strategies than in proliferating cells.

  3. DNA damage assessment by visualization and quantification of DNA damage response

    International Nuclear Information System (INIS)

    Matsuda, Shun; Matsuda, Tomonari; Ikura, Tsuyoshi

    2017-01-01

    DNA damage response (DDR) carries out signal transduction for DNA repair, activation of cell cycle checkpoint, and apoptosis to maintain genome integrity, in response to DNA damage. Many proteins and their post-translational modifications participate in the process. Especially, S139-phosphorylated histone H2AX (γH2AX), which is formed by DNA double-strand breaks (DSBs), is an important factor to bring and retain other DDR proteins to DSB sites, Thus, γH2AX is used as a good indicator of DSBs in clinical study and pharmacology for efficacy evaluation of chemotherapy and radiotherapy, detection of precancerous regions, and others. In regulatory science, γH2AX is also a useful biomarker of genotoxicity of chemicals, since a wide range of genotoxic chemicals induce γH2AX. However, conventional detection methods of γH2AX absolutely require anti-γH2AX antibody whose staining is burdensome and time-consuming, and some of these methods are not so superior in quantitativity. In this review, we introduce two new methods to overcome these limitations, involving an easy-to-use genotoxicity assay using DDR-visualizing cells and an absolute quantification method of γH2AX using liquid chromatography-tandem mass spectrometry (LC/MS/MS). (author)

  4. DNA damage in rats after a single oral exposure to diesel exhaust particles

    DEFF Research Database (Denmark)

    Danielsen, Pernille Høgh; Risom, Lotte; Wallin, Håkan

    2008-01-01

    gavage of diesel exhaust particles (DEP) in terms of DNA damage, oxidative stress and DNA repair in colon epithelial cells, liver, and lung of rats. Eight rats per group were exposed to Standard Reference Material 2975 at 0.064 or 0.64 mg/kg bodyweight for 6 and 24 h. Increased levels of 8-oxo-7...... of DEP, but not in the colon and liver. A general response of the antioxidant defence system is further indicated by elevated levels of heme oxygenase 1 mRNA in the liver and lung 24 h after administration. The level of bulky DNA adducts was increased in liver and lung at both doses after 6 and 24h (DNA...... adducts in colon epithelium were not investigated). In summary, DEP administered via the gastrointestinal tract at low doses relative to ambient exposure generates DNA damage and increase the expression of defence mechanisms in organs such as the lung and liver. The oral exposure route should be taken...

  5. UVA-induced DNA double-strand breaks result from the repair of clustered oxidative DNA damages

    Science.gov (United States)

    Greinert, R.; Volkmer, B.; Henning, S.; Breitbart, E. W.; Greulich, K. O.; Cardoso, M. C.; Rapp, Alexander

    2012-01-01

    UVA (320–400 nm) represents the main spectral component of solar UV radiation, induces pre-mutagenic DNA lesions and is classified as Class I carcinogen. Recently, discussion arose whether UVA induces DNA double-strand breaks (dsbs). Only few reports link the induction of dsbs to UVA exposure and the underlying mechanisms are poorly understood. Using the Comet-assay and γH2AX as markers for dsb formation, we demonstrate the dose-dependent dsb induction by UVA in G1-synchronized human keratinocytes (HaCaT) and primary human skin fibroblasts. The number of γH2AX foci increases when a UVA dose is applied in fractions (split dose), with a 2-h recovery period between fractions. The presence of the anti-oxidant Naringin reduces dsb formation significantly. Using an FPG-modified Comet-assay as well as warm and cold repair incubation, we show that dsbs arise partially during repair of bi-stranded, oxidative, clustered DNA lesions. We also demonstrate that on stretched chromatin fibres, 8-oxo-G and abasic sites occur in clusters. This suggests a replication-independent formation of UVA-induced dsbs through clustered single-strand breaks via locally generated reactive oxygen species. Since UVA is the main component of solar UV exposure and is used for artificial UV exposure, our results shine new light on the aetiology of skin cancer. PMID:22941639

  6. Evaluation of Antioxidant and DNA Damage Protection Activity of the Hydroalcoholic Extract of Desmostachya bipinnata L. Stapf

    Directory of Open Access Journals (Sweden)

    Upendarrao Golla

    2014-01-01

    Full Text Available Desmostachya bipinnata Stapf (Poaceae/Gramineae is an official drug of ayurvedic pharmacopoeia. Various parts of this plant were used extensively in traditional and folklore medicine to cure various human ailments. The present study was aimed to evaluate the antioxidant and DNA damage protection activity of hydroalcoholic extract of Desmostachya bipinnata both in vitro and in vivo, to provide scientific basis for traditional usage of this plant. The extract showed significant antioxidant activity in a dose-dependent manner with an IC50 value of 264.18±3.47 μg/mL in H2O2 scavenging assay and prevented the oxidative damage to DNA in presence of DNA damaging agent (Fenton’s reagent at a concentration of 50 μg/mL. Also, the presence of extract protected yeast cells in a dose-dependent manner against DNA damaging agent (Hydroxyurea in spot assay. Moreover, the presence of extract exhibited significant antioxidant activity in vivo by protecting yeast cells against oxidative stressing agent (H2O2. Altogether, the results of current study revealed that Desmostachya bipinnata is a potential source of antioxidants and lends pharmacological credence to the ethnomedical use of this plant in traditional system of medicine, justifying its therapeutic application for free-radical-induced diseases.

  7. Lithium Chloride Dependent Glycogen Synthase Kinase 3 Inactivation Links Oxidative DNA Damage, Hypertrophy and Senescence in Human Articular Chondrocytes and Reproduces Chondrocyte Phenotype of Obese Osteoarthritis Patients.

    Directory of Open Access Journals (Sweden)

    Serena Guidotti

    Full Text Available Recent evidence suggests that GSK3 activity is chondroprotective in osteoarthritis (OA, but at the same time, its inactivation has been proposed as an anti-inflammatory therapeutic option. Here we evaluated the extent of GSK3β inactivation in vivo in OA knee cartilage and the molecular events downstream GSK3β inactivation in vitro to assess their contribution to cell senescence and hypertrophy.In vivo level of phosphorylated GSK3β was analyzed in cartilage and oxidative damage was assessed by 8-oxo-deoxyguanosine staining. The in vitro effects of GSK3β inactivation (using either LiCl or SB216763 were evaluated on proliferating primary human chondrocytes by combined confocal microscopy analysis of Mitotracker staining and reactive oxygen species (ROS production (2',7'-dichlorofluorescin diacetate staining. Downstream effects on DNA damage and senescence were investigated by western blot (γH2AX, GADD45β and p21, flow cytometric analysis of cell cycle and light scattering properties, quantitative assessment of senescence associated β galactosidase activity, and PAS staining.In vivo chondrocytes from obese OA patients showed higher levels of phosphorylated GSK3β, oxidative damage and expression of GADD45β and p21, in comparison with chondrocytes of nonobese OA patients. LiCl mediated GSK3β inactivation in vitro resulted in increased mitochondrial ROS production, responsible for reduced cell proliferation, S phase transient arrest, and increase in cell senescence, size and granularity. Collectively, western blot data supported the occurrence of a DNA damage response leading to cellular senescence with increase in γH2AX, GADD45β and p21. Moreover, LiCl boosted 8-oxo-dG staining, expression of IKKα and MMP-10.In articular chondrocytes, GSK3β activity is required for the maintenance of proliferative potential and phenotype. Conversely, GSK3β inactivation, although preserving chondrocyte survival, results in functional impairment via

  8. Lithium Chloride Dependent Glycogen Synthase Kinase 3 Inactivation Links Oxidative DNA Damage, Hypertrophy and Senescence in Human Articular Chondrocytes and Reproduces Chondrocyte Phenotype of Obese Osteoarthritis Patients.

    Science.gov (United States)

    Guidotti, Serena; Minguzzi, Manuela; Platano, Daniela; Cattini, Luca; Trisolino, Giovanni; Mariani, Erminia; Borzì, Rosa Maria

    2015-01-01

    Recent evidence suggests that GSK3 activity is chondroprotective in osteoarthritis (OA), but at the same time, its inactivation has been proposed as an anti-inflammatory therapeutic option. Here we evaluated the extent of GSK3β inactivation in vivo in OA knee cartilage and the molecular events downstream GSK3β inactivation in vitro to assess their contribution to cell senescence and hypertrophy. In vivo level of phosphorylated GSK3β was analyzed in cartilage and oxidative damage was assessed by 8-oxo-deoxyguanosine staining. The in vitro effects of GSK3β inactivation (using either LiCl or SB216763) were evaluated on proliferating primary human chondrocytes by combined confocal microscopy analysis of Mitotracker staining and reactive oxygen species (ROS) production (2',7'-dichlorofluorescin diacetate staining). Downstream effects on DNA damage and senescence were investigated by western blot (γH2AX, GADD45β and p21), flow cytometric analysis of cell cycle and light scattering properties, quantitative assessment of senescence associated β galactosidase activity, and PAS staining. In vivo chondrocytes from obese OA patients showed higher levels of phosphorylated GSK3β, oxidative damage and expression of GADD45β and p21, in comparison with chondrocytes of nonobese OA patients. LiCl mediated GSK3β inactivation in vitro resulted in increased mitochondrial ROS production, responsible for reduced cell proliferation, S phase transient arrest, and increase in cell senescence, size and granularity. Collectively, western blot data supported the occurrence of a DNA damage response leading to cellular senescence with increase in γH2AX, GADD45β and p21. Moreover, LiCl boosted 8-oxo-dG staining, expression of IKKα and MMP-10. In articular chondrocytes, GSK3β activity is required for the maintenance of proliferative potential and phenotype. Conversely, GSK3β inactivation, although preserving chondrocyte survival, results in functional impairment via induction of

  9. Effects of alcohol consumption on biomarkers of oxidative damage to DNA and lipids in ethanol-fed pigs.

    Science.gov (United States)

    Petitpas, F; Sichel, F; Hébert, B; Lagadu, S; Beljean, M; Pottier, D; Laurentie, M; Prevost, V

    2013-03-01

    Chronic alcohol consumption is known to result in tissue injury, particularly in the liver, and is considered a major risk factor for cancers of the upper respiratory tract. Here we assessed the oxidative effects of subchronic ethanol consumption on DNA and lipids by measuring biomarkers 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and malondialdehyde (MDA), respectively. Physiological responses of pigs (n = 4) administered ethanol in drinking water for 39 days were compared with those of water-fed pigs (n = 4). Alcoholisation resulted in serum ethanol concentration of 1.90 g L(-1) and in a moderate but significant increase in alanine aminotransferase activity, an index of liver injury. However, between the alcoholised and control groups there were no significant differences in the levels of 8-oxodG (8-oxodG per 10(6) 2'deoxyguanosine) from leucocytes (2.52 ± 0.42 Vs 2.39 ± 0.34) or from target organs, liver, cardia and oesophagus. Serum MDA levels were also similar in ethanol-fed pigs (0.33 ± 0.04 μM) and controls (0.28 ± 0.03 μM). Interestingly, levels of 8-oxodG in cardia were positively correlated with those in oesophagus (Spearman correlation coefficient R = 1, P alcohol consumption may not cause oxidative damage to DNA and lipids as measured by 8-oxodG and MDA, respectively. The duration of alcoholisation and the potential alcohol-induced nutritional deficiency may be critical determinants of ethanol toxicity. Relevant biomarkers, such as factors involved in sensitization to ethanol-induced oxidative stress are required to better elucidate the relationship between alcohol consumption, oxidative stress and carcinogenesis. Copyright © 2011 Elsevier GmbH. All rights reserved.

  10. DNA Damage Response and Immune Defence: Links and Mechanisms

    Directory of Open Access Journals (Sweden)

    Björn Schumacher

    2016-08-01

    Full Text Available DNA damage plays a causal role in numerous human pathologies including cancer, premature aging and chronic inflammatory conditions. In response to genotoxic insults, the DNA damage response (DDR orchestrates DNA damage checkpoint activation and facilitates the removal of DNA lesions. The DDR can also arouse the immune system by for example inducing the expression of antimicrobial peptides as well as ligands for receptors found on immune cells. The activation of immune signalling is triggered by different components of the DDR including DNA damage sensors, transducer kinases, and effectors. In this review, we describe recent advances on the understanding of the role of DDR in activating immune signalling. We highlight evidence gained into (i which molecular and cellular pathways of DDR ac