Phytochemical Ginkgolide B Attenuates Amyloid-β1-42 Induced Oxidative Damage and Altered Cellular Responses in Human Neuroblastoma SH-SY5Y Cells.

PubMed

Gill, Iqbal; Kaur, Sukhchain; Kaur, Navrattan; Dhiman, Monisha; Mantha, Anil K

2017-01-01

Oxidative stress is an upsurge in reactive oxygen/nitrogen species (ROS/RNS), which aggravates damage to cellular components viz. lipids, proteins, and nucleic acids resulting in impaired cellular functions and neurological pathologies including Alzheimer's disease (AD). In the present study, we have examined amyloid-β (Aβ)-induced oxidative stress responses, a major cause for AD, in the undifferentiated and differentiated human neuroblastoma SH-SY5Y cells. Aβ1-42-induced oxidative damage was evaluated on lipids by lipid peroxidation; proteins by protein carbonyls; antioxidant status by SOD and GSH enzyme activities; and DNA and RNA damage levels by evaluating the number of AP sites and 8-OHG base damages produced. In addition, the neuro-protective role of the phytochemical ginkgolide B (GB) in countering Aβ1-42-induced oxidative stress was assessed. We report that the differentiated cells are highly vulnerable to Aβ1-42-induced oxidative stress events as exerted by the deposition of Aβ in AD. Results of the current study suggest that the pre-treatment of GB, followed by Aβ1-42 treatment for 24 h, displayed neuro-protective potential, which countered Aβ1-42-induced oxidative stress responses in both undifferentiated and differentiated SH-SY5Y neuronal cells by: 1) hampering production of ROS and RNS; 2) reducing lipid peroxidation; 3) decreasing protein carbonyl content; 4) restoring antioxidant activities of SOD and GSH enzymes; and 5) maintaining genome integrity by reducing the oxidative DNA and RNA base damages. In conclusion, Aβ1-42 induces oxidative damage to the cellular biomolecules, which are associated with AD pathology, and are protected by the pre-treatment of GB against Aβ-toxicity. Taken together, this study advocates for phytochemical-based therapeutic interventions against AD.

Parkin elimination of mitochondria is important for maintenance of lens epithelial cell ROS levels and survival upon oxidative stress exposure.

PubMed

Brennan, Lisa; Khoury, Josef; Kantorow, Marc

2017-01-01

Age-related cataract is associated with oxidative stress and death of lens epithelial cells (LECs) whose survival is dependent on functional mitochondrial populations. Oxidative stress-induced depolarization/damage of LEC mitochondria results in increased reactive oxygen species (ROS) levels and cell death suggesting the need for a LEC mechanism to remove mitochondria depolarized/damaged upon oxidative stress exposure to prevent ROS release and LEC death. To date, a mechanism(s) for removal of depolarized/damaged LEC mitochondria has yet to be identified and the importance of eliminating oxidative stress-damaged mitochondria to prevent LEC ROS release and death has not been established. Here, we demonstrate that Parkin levels increase in LECs exposed to H 2 O 2 -oxidative stress. We establish that Parkin translocates to LEC mitochondria depolarized upon oxidative stress exposure and that Parkin recruits p62/SQSTM1 to depolarized LEC mitochondria. We demonstrate that translocation of Parkin results in the elimination of depolarized/damaged mitochondria and that Parkin clearance of LEC mitochondria is dependent on its ubiquitin ligase activity. Importantly, we demonstrate that Parkin elimination of damaged LEC mitochondria results in reduced ROS levels and increased survival upon oxidative stress exposure. These results establish that Parkin functions to eliminate LEC mitochondria depolarized/damaged upon oxidative stress exposure and that elimination of damaged mitochondria by Parkin is important for LEC homeostasis and survival. The data also suggest that mitochondrial quality control by Parkin could play a role in lens transparency. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Protective effect of acetyl-L-carnitine on propofol-induced toxicity in embryonic neural stem cells.

PubMed

Liu, Fang; Rainosek, Shuo W; Sadovova, Natalya; Fogle, Charles M; Patterson, Tucker A; Hanig, Joseph P; Paule, Merle G; Slikker, William; Wang, Cheng

2014-05-01

Propofol is a widely used general anesthetic. A growing body of data suggests that perinatal exposure to general anesthetics can result in long-term deleterious effects on brain function. In the developing brain there is evidence that general anesthetics can cause cell death, synaptic remodeling, and altered brain cell morphology. Acetyl-L-carnitine (L-Ca), an anti-oxidant dietary supplement, has been reported to prevent neuronal damage from a variety of causes. To evaluate the ability of L-Ca to protect against propofol-induced neuronal toxicity, neural stem cells were isolated from gestational day 14 rat fetuses and on the eighth day in culture were exposed for 24h to propofol at 10, 50, 100, 300 and 600 μM, with or without L-Ca (10 μM). Markers of cellular proliferation, mitochondrial health, cell death/damage and oxidative damage were monitored to determine: (1) the effects of propofol on neural stem cell proliferation; (2) the nature of propofol-induced neurotoxicity; (3) the degree of protection afforded by L-Ca; and (4) to provide information regarding possible mechanisms underlying protection. After propofol exposure at a clinically relevant concentration (50 μM), the number of dividing cells was significantly decreased, oxidative DNA damage was increased and a significant dose-dependent reduction in mitochondrial function/health was observed. No significant effect on lactase dehydrogenase (LDH) release was observed at propofol concentrations up to 100 μM. The oxidative damage at 50 μM propofol was blocked by L-Ca. Thus, clinically relevant concentrations of propofol induce dose-dependent adverse effects on rat embryonic neural stem cells by slowing or stopping cell division/proliferation and causing cellular damage. Elevated levels of 8-oxoguanine suggest enhanced oxidative damage [reactive oxygen species (ROS) generation] and L-Ca effectively blocks at least some of the toxicity of propofol, presumably by scavenging oxidative species and/or reducing their production. Published by Elsevier B.V.

The mitochondria targeted antioxidant MitoQ protects against fluoroquinolone-induced oxidative stress and mitochondrial membrane damage in human Achilles tendon cells.

PubMed

Lowes, Damon A; Wallace, Carol; Murphy, Michael P; Webster, Nigel R; Galley, Helen F

2009-04-01

Tendinitis and tendon rupture during treatment with fluoroquinolone antibiotics is thought to be mediated via oxidative stress. This study investigated whether ciprofloxacin and moxifloxacin cause oxidative stress and mitochondrial damage in cultured normal human Achilles' tendon cells and whether an antioxidant targeted to mitochondria (MitoQ) would protect against such damage better than a non-mitochondria targeted antioxidant. Human tendon cells from normal Achilles' tendons were exposed to 0-0.3 mM antibiotic for 24 h and 7 days in the presence of 1 microM MitoQ or an untargeted form, idebenone. Both moxifloxacin and ciprofloxacin resulted in up to a 3-fold increase in the rate of oxidation of dichlorodihydrofluorescein, a marker of general oxidative stress in tenocytes (p<0.0001) and loss of mitochondrial membrane permeability (p<0.001). In cells treated with MitoQ the oxidative stress was less and mitochondrial membrane potential was maintained. Mitochondrial damage to tenocytes during fluoroquinolone treatment may be involved in tendinitis and tendon rupture.

Oxidation in the nucleotide pool, the DNA damage response and cellular senescence: Defective bricks build a defective house.

PubMed

Rai, Priyamvada

2010-11-28

Activation of persistent DNA damage response (DDR) signaling is associated with the induction of a permanent proliferative arrest known as cellular senescence, a phenomenon intrinsically linked to both tissue aging as well as tumor suppression. The DNA damage observed in senescent cells has been attributed to elevated levels of reactive oxygen species (ROS), failing DNA damage repair processes, and/or oncogenic activation. It is not clear how labile molecules such as ROS are able to damage chromatin-bound DNA to a sufficient extent to invoke persistent DNA damage and DDR signaling. Recent evidence suggests that the nucleotide pool is a significant target for oxidants and that oxidized nucleotides, once incorporated into genomic DNA, can lead to the induction of a DNA strand break-associated DDR that triggers senescence in normal cells and in cells sustaining oncogene activation. Evasion of this DDR and resulting senescence is a key step in tumor progression. This review will explore the role of oxidation in the nucleotide pool as a major effector of oxidative stress-induced genotoxic damage and DDR in the context of cellular senescence and tumorigenic transformation. 2010 Elsevier B.V. All rights reserved.

Effects of maternal subclinical hypothyroidism on amniotic fluid cells oxidative status.

PubMed

Novakovic, Tanja R; Dolicanin, Zana C; Djordjevic, Natasa Z

2018-06-01

In this study, we researched the effects of maternal subclinical hypothyroidism on the amniotic fluid cells oxidative metabolism during the first trimester of pregnancy. Oxidative stress and damage biomarkers were assayed in the amniotic fluid cells of healthy and pregnant women with subclinical hypothyroidism. Obtained results show that amniotic fluid cells of pregnant women with subclinical hypothyroidism have significantly higher concentrations of oxidative stress biomarkers (superoxide anion, nitric oxide, peroxynitrite) and oxidative damage (lipid peroxide and micronuclei frequency), but lower concentrations of hydrogen peroxide and oxidized glutathione in comparison to healthy pregnant women. We also showed that oxidative stress biomarkers were positively correlated with micronuclei frequency and lipid peroxide concentration in amniotic fluid cells of pregnant women with subclinical hypothyroidism. The present study provides the first evidence for prooxidative effects of maternal subclinical hypothyroidism on the fetus obtained by the estimating oxidative metabolism in the amniotic fluid cells. Copyright © 2018 Elsevier Inc. All rights reserved.

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

PubMed

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 our cell viability data indicates that targeting MTH1 will likely not be an across-the-board effective NSCLC therapeutic strategy; rather it induces non-cytotoxic DNA damage that could promote cancer heterogeneity and evolution.

Using digital flow cytometry to assess the degradation of three cyanobacteria species after oxidation processes.

PubMed

Wert, Eric C; Dong, Mei Mei; Rosario-Ortiz, Fernando L

2013-07-01

Depending on drinking water treatment conditions, oxidation processes may result in the degradation of cyanobacteria cells causing the release of toxic metabolites (microcystin), odorous metabolites (MIB, geosmin), or disinfection byproduct precursors. In this study, a digital flow cytometer (FlowCAM(®)) in combination with chlorophyll-a analysis was used to evaluate the ability of ozone, chlorine, chlorine dioxide, and chloramine to damage or lyse cyanobacteria cells added to Colorado River water. Microcystis aeruginosa (MA), Oscillatoria sp. (OSC) and Lyngbya sp. (LYN) were selected for the study due to their occurrence in surface water supplies, metabolite production, and morphology. Results showed that cell damage was observed without complete lysis or fragmentation of the cell membrane under many of the conditions tested. During ozone and chlorine experiments, the unicellular MA was more susceptible to oxidation than the filamentous OSC and LYN. Rate constants were developed based on the loss of chlorophyll-a and oxidant exposure, which showed the oxidants degraded MA, OSC, and LYN according to the order of ozone > chlorine ~ chlorine dioxide > chloramine. Digital and binary images taken by the digital flow cytometer provided qualitative insight regarding cell damage. When applying this information, drinking water utilities can better understand the risk of cell damage or lysis during oxidation processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Achieving the Balance between ROS and Antioxidants: When to Use the Synthetic Antioxidants

PubMed Central

Poljsak, Borut; Šuput, Dušan; Milisav, Irina

2013-01-01

Free radical damage is linked to formation of many degenerative diseases, including cancer, cardiovascular disease, cataracts, and aging. Excessive reactive oxygen species (ROS) formation can induce oxidative stress, leading to cell damage that can culminate in cell death. Therefore, cells have antioxidant networks to scavenge excessively produced ROS. The balance between the production and scavenging of ROS leads to homeostasis in general; however, the balance is somehow shifted towards the formation of free radicals, which results in accumulated cell damage in time. Antioxidants can attenuate the damaging effects of ROS in vitro and delay many events that contribute to cellular aging. The use of multivitamin/mineral supplements (MVMs) has grown rapidly over the past decades. Some recent studies demonstrated no effect of antioxidant therapy; sometimes the intake of antioxidants even increased mortality. Oxidative stress is damaging and beneficial for the organism, as some ROS are signaling molecules in cellular signaling pathways. Lowering the levels of oxidative stress by antioxidant supplements is not beneficial in such cases. The balance between ROS and antioxidants is optimal, as both extremes, oxidative and antioxidative stress, are damaging. Therefore, there is a need for accurate determination of individual's oxidative stress levels before prescribing the supplement antioxidants. PMID:23738047

Toxicity of nano- and micro-sized ZnO particles in human lung epithelial cells

NASA Astrophysics Data System (ADS)

Lin, Weisheng; Xu, Yi; Huang, Chuan-Chin; Ma, Yinfa; Shannon, Katie B.; Chen, Da-Ren; Huang, Yue-Wern

2009-01-01

This is the first comprehensive study to evaluate the cytotoxicity, biochemical mechanisms of toxicity, and oxidative DNA damage caused by exposing human bronchoalveolar carcinoma-derived cells (A549) to 70 and 420 nm ZnO particles. Particles of either size significantly reduced cell viability in a dose- and time-dependent manner within a rather narrow dosage range. Particle mass-based dosimetry and particle-specific surface area-based dosimetry yielded two distinct patterns of cytotoxicity in both 70 and 420 nm ZnO particles. Elevated levels of reactive oxygen species (ROS) resulted in intracellular oxidative stress, lipid peroxidation, cell membrane leakage, and oxidative DNA damage. The protective effect of N-acetylcysteine on ZnO-induced cytotoxicity further implicated oxidative stress in the cytotoxicity. Free Zn2+ and metal impurities were not major contributors of ROS induction as indicated by limited free Zn2+ cytotoxicity, extent of Zn2+ dissociation in the cell culture medium, and inductively-coupled plasma-mass spectrometry metal analysis. We conclude that (1) exposure to both sizes of ZnO particles leads to dose- and time-dependent cytotoxicity reflected in oxidative stress, lipid peroxidation, cell membrane damage, and oxidative DNA damage, (2) ZnO particles exhibit a much steeper dose-response pattern unseen in other metal oxides, and (3) neither free Zn2+ nor metal impurity in the ZnO particle samples is the cause of cytotoxicity.

Involvement of DNA polymerase beta in repairing oxidative damages induced by antitumor drug adriamycin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Shukun; Wu Mei; Zhang Zunzhen, E-mail: zhangzunzhen@163.co

2010-08-01

Adriamycin (ADM) is a widely used antineoplastic drug. However, the increasing cellular resistance has become a serious limitation to ADM clinical application. The most important mechanism related to ADM-induced cell death is oxidative DNA damage mediated by reactive oxygen species (ROS). Base excision repair (BER) is a major pathway in the repair of DNA single strand break (SSB) and oxidized base. In this study, we firstly applied the murine embryo fibroblasts wild-type (pol {beta} +/+) and homozygous pol {beta} null cell (pol {beta} -/-) as a model to investigate ADM DNA-damaging effects and the molecular basis underlying these effects. Here,more » cellular sensitivity to ADM was examined using colorimetric assay and colony forming assay. ADM-induced cellular ROS level and the alteration of superoxide dismutase (SOD) activity were measured by commercial kits. Further, DNA strand break, chromosomal damage and gene mutation were assessed by comet assay, micronucleus test and hprt gene mutation assay, respectively. The results showed that pol {beta} -/- cells were more sensitive to ADM compared with pol {beta} +/+ cells and more severe SSB and chromosomal damage as well as higher hprt gene mutation frequency were observed in pol {beta} -/- cells. ROS level in pol {beta} -/- cells increased along with decreased activity of SOD. These results demonstrated that pol {beta} deficiency could enable ROS accumulation with SOD activity decrease, further elevate oxidative DNA damage, and subsequently result in SSB, chromosome cleavage as well as gene mutation, which may be partly responsible for the cytotoxicity of ADM and the hypersensitivity of pol {beta} -/- cells to ADM. These findings suggested that pol {beta} is vital for repairing oxidative damage induced by ADM.« less

Bactericidal antibiotics induce mitochondrial dysfunction and oxidative damage in Mammalian cells.

PubMed

Kalghatgi, Sameer; Spina, Catherine S; Costello, James C; Liesa, Marc; Morones-Ramirez, J Ruben; Slomovic, Shimyn; Molina, Anthony; Shirihai, Orian S; Collins, James J

2013-07-03

Prolonged antibiotic treatment can lead to detrimental side effects in patients, including ototoxicity, nephrotoxicity, and tendinopathy, yet the mechanisms underlying the effects of antibiotics in mammalian systems remain unclear. It has been suggested that bactericidal antibiotics induce the formation of toxic reactive oxygen species (ROS) in bacteria. We show that clinically relevant doses of bactericidal antibiotics-quinolones, aminoglycosides, and β-lactams-cause mitochondrial dysfunction and ROS overproduction in mammalian cells. We demonstrate that these bactericidal antibiotic-induced effects lead to oxidative damage to DNA, proteins, and membrane lipids. Mice treated with bactericidal antibiotics exhibited elevated oxidative stress markers in the blood, oxidative tissue damage, and up-regulated expression of key genes involved in antioxidant defense mechanisms, which points to the potential physiological relevance of these antibiotic effects. The deleterious effects of bactericidal antibiotics were alleviated in cell culture and in mice by the administration of the antioxidant N-acetyl-l-cysteine or prevented by preferential use of bacteriostatic antibiotics. This work highlights the role of antibiotics in the production of oxidative tissue damage in mammalian cells and presents strategies to mitigate or prevent the resulting damage, with the goal of improving the safety of antibiotic treatment in people.

Bactericidal Antibiotics Induce Mitochondrial Dysfunction and Oxidative Damage in Mammalian Cells

PubMed Central

Costello, James C.; Liesa, Marc; Morones-Ramirez, J Ruben; Slomovic, Shimyn; Molina, Anthony; Shirihai, Orian S.; Collins, James J.

2013-01-01

Prolonged antibiotic treatment can lead to detrimental side effects in patients, including ototoxicity, nephrotoxicity, and tendinopathy, yet the mechanisms underlying the effects of antibiotics in mammalian systems remain unclear. It has been suggested that bactericidal antibiotics induce the formation of toxic reactive oxygen species (ROS) in bacteria. We show that clinically relevant doses of bactericidal antibiotics—quinolones, aminoglycosides, and β-lactams—cause mitochondrial dysfunction and ROS overproduction in mammalian cells. We demonstrate that these bactericidal antibiotic–induced effects lead to oxidative damage to DNA, proteins, and membrane lipids. Mice treated with bactericidal antibiotics exhibited elevated oxidative stress markers in the blood, oxidative tissue damage, and up-regulated expression of key genes involved in antioxidant defense mechanisms, which points to the potential physiological relevance of these antibiotic effects. The deleterious effects of bactericidal antibiotics were alleviated in cell culture and in mice by the administration of the antioxidant N-acetyl-L-cysteine or prevented by preferential use of bacteriostatic antibiotics. This work highlights the role of antibiotics in the production of oxidative tissue damage in mammalian cells and presents strategies to mitigate or prevent the resulting damage, with the goal of improving the safety of antibiotic treatment in people. PMID:23825301

Oligodendroglia are particularly vulnerable to oxidative damage after neurotrauma in vivo.

PubMed

Giacci, Marcus K; Bartlett, Carole A; Smith, Nicole M; Iyer, K Swaminathan; Toomey, Lillian M; Jiang, Haibo; Guagliardo, Paul; Kilburn, Matt R; Fitzgerald, Melinda

2018-06-18

Loss of function following injury to the central nervous system is worsened by secondary degeneration of neurons and glia surrounding the injury and initiated by oxidative damage. However, it is not yet known which cellular populations and structures are most vulnerable to oxidative damage in vivo Using Nanoscale secondary ion mass spectrometry (NanoSIMS), oxidative damage was semi-quantified within cellular subpopulations and structures of optic nerve vulnerable to secondary degeneration, following a partial transection of the optic nerve in adult female PVG rats. Simultaneous assessment of cellular subpopulations and structures revealed oligodendroglia as the most vulnerable to DNA oxidation following injury. 5-ethynyl-2'-deoxyuridine (EdU) was used to label cells that proliferated in the first 3 days after injury. Injury led to increases in DNA, protein and lipid damage in OPCs and mature oligodendrocytes at 3 days, regardless of proliferative state, associated with a decline in the numbers of OPCs at 7 days. O4+ pre-oligodendrocytes also exhibited increased lipid peroxidation. Interestingly, EdU+ mature oligodendrocytes derived after injury demonstrated increased early susceptibility to DNA damage and lipid peroxidation. However, EdU- mature oligodendrocytes with high 8OHdG immunoreactivity were more likely to be caspase3+. By day 28, newly derived mature oligodendrocytes had significantly reduced MYRF mRNA indicating that the myelination potential of these cells may be reduced. The proportion of caspase3+ oligodendrocytes remained higher in EdU- cells. Innovative use of NanoSIMS together with traditional immunohistochemistry and in situ hybridisation have enabled the first demonstration of subpopulation specific oligodendroglial vulnerability to oxidative damage, due to secondary degeneration in vivo. SIGNIFICANCE STATEMENT Injury to the central nervous system is characterised by oxidative damage in areas adjacent to the injury. However, the cellular subpopulations and structures most vulnerable to this damage remain to be elucidated. Here we use powerful NanoSIMS techniques to show increased oxidative damage in oligodendroglia and axons and to demonstrate that cells early in the oligodendroglial lineage are the most vulnerable to DNA oxidation. Further immunohistochemical and in situ hybridisation investigation reveals that mature oligodendrocytes derived after injury are more vulnerable to oxidative damage than their counterparts existing at the time of injury and have reduced MYRF mRNA, yet pre-existing oligodendrocytes are more likely to die. Copyright © 2018 the authors.

ROS-induced oxidative stress and apoptosis-like event directly affect the cell viability of cryopreserved embryogenic callus in Agapanthus praecox.

PubMed

Zhang, Di; Ren, Li; Chen, Guan-Qun; Zhang, Jie; Reed, Barbara M; Shen, Xiao-Hui

2015-09-01

Oxidative stress and apoptosis-like programmed cell death, induced in part by H 2 O 2 , are two key factors that damage cells during plant cryopreservation. Their inhibition can improve cell viability. We hypothesized that oxidative stress and apoptosis-like event induced by ROS seriously impact plant cell viability during cryopreservation. This study documented changes in cell morphology and ultrastructure, and detected dynamic changes in ROS components (O 2 (·-) , H2O2 and OH·), antioxidant systems, and programmed cell death (PCD) events during embryonic callus cryopreservation of Agapanthus praecox. Plasmolysis, organelle ultrastructure changes, and increases in malondialdehyde (a membrane lipid peroxidation product) suggested that oxidative damage and PCD events occurred at several early cryopreservation steps. PCD events including autophagy, apoptosis-like, and necrosis also occurred at later stages of cryopreservation, and most were apoptosis. H2O2 is the most important ROS molecule mediating oxidative damage and affecting cell viability, and catalase and AsA-GSH cycle are involved in scavenging the intracellular H2O2 and protecting the cells against stress damage in the whole process. Gene expression studies verified changes of antioxidant system and PCD-related genes at the main steps of the cryopreservation process that correlated with improved cell viability. Reducing oxidative stress or inhibition of apoptosis-like event by deactivating proteases improved cryopreserved cell viability from 49.14 to 86.85 % and 89.91 %, respectively. These results verify our model of ROS-induced oxidative stress and apoptosis-like event in plant cryopreservation. This study provided a novel insight into cell stress response mechanisms in cryopreservation.

Protective Effect of Edaravone Against Aβ25-35-Induced Mitochondrial Oxidative Damage in SH-SY5Y Cells.

PubMed

Zhang, G-L; Zhang, L; Guo, Y-Y; Ma, Z-L; Wang, H-Y; Li, T; Liu, J; Du, Y; Yao, L; Li, T-T; Du, J-M

2017-05-20

Amyloid-β (Aβ)-induced oxidative stress plays an important role in the pathogenesis of Alzheimer's disease (AD). Recent studies show that Aβ accumulation may lead to mitochondrial oxidative damage. In the present study, we investigated the protective effect of edaravone on mitochondrial damage in SH-SY5Y cells treated with Aβ25-35. SH-SY5Y cells were pre-treated with 20, 40 or 80 μM edaravone before treatment with 25 μM Aβ25-35. After 24h cell culture, cellular apoptosis, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm), ATP levels and mitochondrial morphology were evaluated. SH-SY5Y cells exposed to Aβ25-35 had high levels of apoptosis and ROS; loss of ΔΨm, decreased ATP levels and presence of mitochondrial swelling. However, these effects were significantly inhibited by edaravone pre-treatment. These results indicate that edaravone prevents mitochondria oxidative damage caused by Aβ in SH-SY5Y cells, which suggests that it may have potential clinical application in AD therapy.

Mechanisms of β-Cell Death in Response to Double-Stranded (ds) RNA and Interferon-γ

PubMed Central

Scarim, Anna L.; Arnush, Marc; Blair, Libby A.; Concepcion, Josephine; Heitmeier, Monique R.; Scheuner, Donalyn; Kaufman, Randal J.; Ryerse, Jan; Buller, R. Mark; Corbett, John A.

2001-01-01

Viral infection is one environmental factor that has been implicated as a precipitating event that may initiate β-cell damage during the development of diabetes. This study examines the mechanisms by which the viral replicative intermediate, double-stranded (ds) RNA impairs β-cell function and induces β-cell death. The synthetic dsRNA molecule polyinosinic-polycytidylic acid (poly IC) stimulates β-cell DNA damage and apoptosis without impairing islet secretory function. In contrast, the combination of poly IC and interferon (IFN)-γ stimulates DNA damage, apoptosis, and necrosis of islet cells, and this damage is associated with the inhibition of glucose-stimulated insulin secretion. Nitric oxide mediates the inhibitory and destructive actions of poly IC + IFN-γ on insulin secretion and islet cell necrosis. Inhibitors of nitric oxide synthase, aminoguanidine, and NG-monomethyl-l-arginine, attenuate poly IC + IFN-γ-induced DNA damage to levels observed in response to poly IC alone, prevent islet cell necrosis, and prevent the inhibitory actions on glucose-stimulated insulin secretion. NG-monomethyl-l-arginine fails to prevent poly IC- and poly IC + IFN-γ-induced islet cell apoptosis. PKR, the dsRNA-dependent protein kinase that mediates the antiviral response in infected cells, is required for poly IC- and poly IC + IFN-γ-induced islet cell apoptosis, but not nitric oxide-mediated islet cell necrosis. Alone, poly IC fails to stimulate DNA damage in islets isolated from PKR-deficient mice; however, nitric oxide-dependent DNA damage induced by the combination of poly IC + IFN-γ is not attenuated by the genetic absence of PKR. These findings indicate that dsRNA stimulates PKR-dependent islet cell apoptosis, an event that is associated with normal islet secretory function. In contrast, poly IC + IFN-γ-induced inhibition of glucose-stimulated insulin secretion and islet cell necrosis are events that are mediated by islet production of nitric oxide. These findings suggest that at least one IFN-γ-induced antiviral response (islet cell necrosis) is mediated through a PKR-independent pathway. PMID:11438474

Nanomaterial induction of oxidative stress in lung epithelial cells and macrophages

NASA Astrophysics Data System (ADS)

Wang, Lin; Pal, Anoop K.; Isaacs, Jacqueline A.; Bello, Dhimiter; Carrier, Rebecca L.

2014-09-01

Oxidative stress in the lung epithelial A549 cells and macrophages J774A.1 due to contact with commercially important nanomaterials [i.e., nano-silver (nAg), nano-alumina (nAl2O3), single-wall carbon nanotubes (CNT), and nano-titanium oxide anatase (nTiO2)] was evaluated. Nanomaterial-induced intracellular oxidative stress was analyzed by both H2DCFDA fluorescein probe and GSH depletion, extracellular oxidative stress was assessed by H2HFF fluorescein probes, and the secretion of chemokine IL-8 by A549 cells due to elevation of cellular oxidative stress was also monitored, in order to provide a comprehensive in vitro study on nanomaterial-induced oxidative stress in lung. In addition, results from this study were also compared with an acellular "ferric reducing ability of serum" (FRAS) assay and a prokaryotic cell-based assay in evaluating oxidative damage caused by the same set of nanomaterials, for comparison purposes. In general, it was found that nanomaterial-induced oxidative stress is highly cell-type dependent. In A549 lung epithelial cells, nAg appeared to induce highest level of oxidative stress and cell death followed by CNT, nTiO2, and nAl2O3. Different biological oxidative damage (BOD) assays' (i.e., H2DCFA, GSH, and IL-8 release) results generally agreed with each other, and the same trends of nanomaterial-induced BOD were also observed in acellular FRAS and prokaryotic E. coli K12-based assay. In macrophage J774A.1 cells, nAl2O3 and nTiO2 appeared to induce highest levels of oxidative stress. These results suggest that epithelial and macrophage cell models may provide complimentary information when conducting cell-based assays to evaluate nanomaterial-induced oxidative damage in lung.

Mitochondrial quality control: decommissioning power plants in neurodegenerative diseases.

PubMed

Mukherjee, Rukmini; Chakrabarti, Oishee

2013-01-01

The cell has an intricate quality control system to protect its mitochondria from oxidative stress. This surveillance system is multi-tiered and comprises molecules that are present inside the mitochondria, in the cytosol, and in other organelles like the nucleus and endoplasmic reticulum. These molecules cross talk with each other and protect the mitochondria from oxidative stress. Oxidative stress is a fundamental part of early disease pathogenesis of neurodegenerative diseases. These disorders also damage the cellular quality control machinery that protects the cell against oxidative stress. This exacerbates the oxidative damage and causes extensive neuronal cell death that is characteristic of neurodegeneration.

Protective activity of Panduratin A against Thioacetamide-induced oxidative damage: demonstration with in vitro experiments using WRL-68 liver cell line

PubMed Central

2013-01-01

Background Chalcone Panduratin A (PA) has been known for its antioxidant property, but its merits against oxidative damage in liver cells has yet to be investigated. Hence, the paper aimed at accomplishing this task with normal embryonic cell line WRL-68. Methods PA was isolated from Boesenbergia rotunda rhizomes and its 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and ferric reducing power (FRAP) activities were measured in comparison with that of the standard reference drug Silymarin (SI). Oxidative damage was induced by treating the cells with 0.04 g/ml of toxic thioacetamide for 60 minutes followed by treatment with 1, 10 and 100 μg/ml concentrations of either PA or SI. The severities of oxidative stress in the control and experimental groups of cells were measured by Malondialdehyde (MDA) levels, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. Results PA exhibited an acceptable DPPH scavenging and FRAP activities close to that of Silymarin. Treating the injured cells with PA significantly reduced the MDA level and increased the cell viability, comparable to SI. The activities of SOD, CAT and GPx were significantly elevated in the PA-treated cells in a dose dependent manner and again similar to SI. Conclusion Collectively, data suggested that PA has capacity to protect normal liver cells from oxidative damage, most likely via its antioxidant scavenging ability. PMID:24156366

DNA damage in cells exhibiting radiation-induced genomic instability

DOE PAGES

Keszenman, Deborah J.; Kolodiuk, Lucia; Baulch, Janet E.

2015-02-22

Cells exhibiting radiation induced genomic instability exhibit varied spectra of genetic and chromosomal aberrations. Even so, oxidative stress remains a common theme in the initiation and/or perpetuation of this phenomenon. Isolated oxidatively modified bases, abasic sites, DNA single strand breaks and clustered DNA damage are induced in normal mammalian cultured cells and tissues due to endogenous reactive oxygen species generated during normal cellular metabolism in an aerobic environment. While sparse DNA damage may be easily repaired, clustered DNA damage may lead to persistent cytotoxic or mutagenic events that can lead to genomic instability. In this study, we tested the hypothesismore » that DNA damage signatures characterised by altered levels of endogenous, potentially mutagenic, types of DNA damage and chromosomal breakage are related to radiation-induced genomic instability and persistent oxidative stress phenotypes observed in the chromosomally unstable progeny of irradiated cells. The measurement of oxypurine, oxypyrimidine and abasic site endogenous DNA damage showed differences in non-double-strand breaks (DSB) clusters among the three of the four unstable clones evaluated as compared to genomically stable clones and the parental cell line. These three unstable clones also had increased levels of DSB clusters. The results of this study demonstrate that each unstable cell line has a unique spectrum of persistent damage and lead us to speculate that alterations in DNA damage signaling and repair may be related to the perpetuation of genomic instability.« less

The effect of green, black and white tea on the level of alpha and gamma tocopherols in free radical-induced oxidative damage of human red blood cells.

PubMed

Gawlik, Małgorzata; Czajka, Aneta

2007-01-01

The present study was undertaken to investigate the effect of aqueous tea extracts on lipid peroxidation and alpha and gamma tocopherols concentration in the oxidative damage of human red blood cells (RBC). RBC was taken as the model for study of the oxidative damage was induced by cumene hydroperoxide (cumOOH). The antioxidative property of leaf green tea, leaf and granulate of black tea and white tea at levels 1, 2, 4 g/150 mL of water were evaluated. The correlation was observed between reducing power of tea extract and formation of malondialdehyde--MDA (an indicator of lipid peroxidation) in oxidative damage of RBC. All tea extracts at level of 4 g/150 mL of water significantly decreased concentration of MDA. The extract of green tea in comparison to black and white tea extracts at the same levels seems to be a better protective agent against oxidative stress. The antioxidant synergism between components extracted from leaves of green tea and endogenous alpha tocopherol in the oxidative damage of red blood cells was observed. The consumption of alpha tocopherol in oxidative damage of RBC was the lowest after treatment with the highest dose of green tea extract. All tea extracts did not protect against decrease of gamma tocopherol in human erythrocytes treated with cumOOH.

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.

PubMed

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.

Oxidative stress in bacteria (Pseudomonas putida) exposed to nanostructures of silicon carbide.

PubMed

Borkowski, Andrzej; Szala, Mateusz; Kowalczyk, Paweł; Cłapa, Tomasz; Narożna, Dorota; Selwet, Marek

2015-09-01

Silicon carbide (SiC) nanostructures produced by combustion synthesis can cause oxidative stress in the bacterium Pseudomonas putida. The results of this study showed that SiC nanostructures damaged the cell membrane, which can lead to oxidative stress in living cells and to the loss of cell viability. As a reference, micrometric SiC was also used, which did not exhibit toxicity toward cells. Oxidative stress was studied by analyzing the activity of peroxidases, and the expression of the glucose-6-phosphate dehydrogenase gene (zwf1) using real-time PCR and northern blot techniques. Damage to nucleic acid was studied by isolating and hydrolyzing plasmids with the formamidopyrimidine [fapy]-DNA glycosylase (also known as 8-oxoguanine DNA glycosylase) (Fpg), which is able to detect damaged DNA. The level of viable microbial cells was investigated by propidium iodide and acridine orange staining. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of HSPA1A promoter-driven luciferase reporter gene assays in human cells for assessing the oxidative damage induced by silver nanoparticles.

PubMed

Xin, Lili; Wang, Jianshu; Zhang, Leshuai W; Che, Bizhong; Dong, Guangzhu; Fan, Guoqiang; Cheng, Kaiming

2016-08-01

The exponential increase in the total number of engineered nanoparticles in consumer products requires novel tools for rapid and cost-effective toxicology screening. In order to assess the oxidative damage induced by nanoparticles, toxicity test systems based on a human HSPA1A promoter-driven luciferase reporter in HepG2, LO2, A549, and HBE cells were established. After treated with heat shock and a group of silver nanoparticles (AgNPs) with different primary particle sizes, the cell viability, oxidative damage, and luciferase activity were determined. The time-dependent Ag(+) ions release from AgNPs in cell medium was also evaluated. Our results showed that heat shock produced a strong time-dependent induction of relative luciferase activity in the four luciferase reporter cells. Surprisingly, at 4h of recovery, the relative luciferase activity was >98× the control level in HepG2-luciferase cells. Exposure to different sizes of AgNPs resulted in activation of the HSPA1A promoter in a dose-dependent manner, even at low cytotoxic or non-cytotoxic doses. The smaller (5nm) AgNPs were more potent in luciferase induction than the larger (50 and 75nm) AgNPs. These results were generally in accordance with the oxidative damage indicated by malondialdehyde concentration, reactive oxygen species induction and glutathione depletion, and Ag(+) ions release in cell medium. Compared with the other three luciferase reporter cells, the luciferase signal in HepG2-luciferase cells is obviously more sensitive and stable. We conclude that the luciferase reporter cells, especially the HepG2-luciferase cells, could provide a valuable tool for rapid screening of the oxidative damage induced by AgNPs. Copyright © 2016 Elsevier Inc. All rights reserved.

Antioxidative effects of fermented sesame sauce against hydrogen peroxide-induced oxidative damage in LLC-PK1 porcine renal tubule cells

PubMed Central

Song, Jia-Le; Choi, Jung-Ho; Seo, Jae-Hoon; Kil, Jeung-Ha

2014-01-01

BACKGROUND/OBJECTIVES This study was performed to investigate the in vitro antioxidant and cytoprotective effects of fermented sesame sauce (FSeS) against hydrogen peroxide (H2O2)-induced oxidative damage in renal proximal tubule LLC-PK1 cells. MATERIALS/METHODS 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (•OH), and H2O2 scavenging assay was used to evaluate the in vitro antioxidant activity of FSeS. To investigate the cytoprotective effect of FSeS against H2O2-induced oxidative damage in LLC-PK1 cells, the cellular levels of reactive oxygen species (ROS), lipid peroxidation, and endogenous antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) were measured. RESULTS The ability of FSeS to scavenge DPPH, •OH and H2O2 was greater than that of FSS and AHSS. FSeS also significantly inhibited H2O2-induced (500 µM) oxidative damage in the LLC-PK1 cells compared to FSS and AHSS (P < 0.05). Following treatment with 100 µg/mL of FSeS and FSS to prevent H2O2-induced oxidation, cell viability increased from 56.7% (control) to 83.7% and 75.6%, respectively. However, AHSS was not able to reduce H2O2-induced cell damage (viability of the AHSS-treated cells was 54.6%). FSeS more effectively suppressed H2O2-induced ROS generation and lipid peroxidation compared to FSS and AHSS (P < 0.05). Compared to the other sauces, FSeS also significantly increased cellular CAT, SOD, and GSH-px activities and mRNA expression (P < 0.05). CONCULUSIONS These results from the present study suggest that FSeS is an effective radical scavenger and protects against H2O2-induced oxidative damage in LLC-PK1 cells by reducing ROS levels, inhibiting lipid peroxidation, and stimulating antioxidant enzyme activity. PMID:24741396

MitoQ blunts mitochondrial and renal damage during cold preservation of porcine kidneys.

PubMed

Parajuli, Nirmala; Campbell, Lia H; Marine, Akira; Brockbank, Kelvin G M; Macmillan-Crow, Lee Ann

2012-01-01

Cold preservation has greatly facilitated the use of cadaveric kidneys for transplantation but damage occurs during the preservation episode. It is well established that oxidant production increases during cold renal preservation and mitochondria are a key target for injury. Our laboratory has demonstrated that cold storage of renal cells and rat kidneys leads to increased mitochondrial superoxide levels and mitochondrial electron transport chain damage, and that addition of Mitoquinone (MitoQ) to the preservation solutions blunted this injury. In order to better translate animal studies, the inclusion of large animal models is necessary to develop safe preclinical protocols. Therefore, we tested the hypothesis that addition of MitoQ to cold storage solution preserves mitochondrial function by decreasing oxidative stress, leading to less renal tubular damage during cold preservation of porcine kidneys employing a standard criteria donor model. Results showed that cold storage significantly induced oxidative stress (nitrotyrosine), renal tubular damage, and cell death. Using High Resolution Respirometry and fresh porcine kidney biopsies to assess mitochondrial function we showed that MitoQ significantly improved complex II/III respiration of the electron transport chain following 24 hours of cold storage. In addition, MitoQ blunted oxidative stress, renal tubular damage, and cell death after 48 hours. These results suggested that MitoQ decreased oxidative stress, tubular damage and cell death by improving mitochondrial function during cold storage. Therefore this compound should be considered as an integral part of organ preservation solution prior to transplantation.

MitoQ Blunts Mitochondrial and Renal Damage during Cold Preservation of Porcine Kidneys

PubMed Central

Parajuli, Nirmala; Campbell, Lia H.; Marine, Akira; Brockbank, Kelvin G. M.; MacMillan-Crow, Lee Ann

2012-01-01

Cold preservation has greatly facilitated the use of cadaveric kidneys for transplantation but damage occurs during the preservation episode. It is well established that oxidant production increases during cold renal preservation and mitochondria are a key target for injury. Our laboratory has demonstrated that cold storage of renal cells and rat kidneys leads to increased mitochondrial superoxide levels and mitochondrial electron transport chain damage, and that addition of Mitoquinone (MitoQ) to the preservation solutions blunted this injury. In order to better translate animal studies, the inclusion of large animal models is necessary to develop safe preclinical protocols. Therefore, we tested the hypothesis that addition of MitoQ to cold storage solution preserves mitochondrial function by decreasing oxidative stress, leading to less renal tubular damage during cold preservation of porcine kidneys employing a standard criteria donor model. Results showed that cold storage significantly induced oxidative stress (nitrotyrosine), renal tubular damage, and cell death. Using High Resolution Respirometry and fresh porcine kidney biopsies to assess mitochondrial function we showed that MitoQ significantly improved complex II/III respiration of the electron transport chain following 24 hours of cold storage. In addition, MitoQ blunted oxidative stress, renal tubular damage, and cell death after 48 hours. These results suggested that MitoQ decreased oxidative stress, tubular damage and cell death by improving mitochondrial function during cold storage. Therefore this compound should be considered as an integral part of organ preservation solution prior to transplantation. PMID:23139796

Carnitine prevents the early mitochondrial damage induced by methylglyoxal bis(guanylhydrazone) in L1210 leukaemia cells.

PubMed

Nikula, P; Ruohola, H; Alhonen-Hongisto, L; Jänne, J

1985-06-01

We previously found that the anti-cancer drug methylglyoxal bis(guanylhydrazone) (mitoguazone) depresses carnitine-dependent oxidation of long-chain fatty acids in cultured mouse leukaemia cells [Nikula, Alhonen-Hongisto, Seppänen & Jänne (1984) Biochem. Biophys. Res. Commun. 120, 9-14]. We have now investigated whether carnitine also influences the development of the well-known mitochondrial damage produced by the drug in L1210 leukaemia cells. Palmitate oxidation was distinctly inhibited in tumour cells exposed to 5 microM-methylglyoxal bis(guanylhydrazone) for only 7 h. Electron-microscopic examination of the drug-exposed cells revealed that more than half of the mitochondria were severely damaged. Similar exposure of the leukaemia cells to the drug in the presence of carnitine not only abolished the inhibition of fatty acid oxidation but almost completely prevented the drug-induced mitochondrial damage. The protection provided by carnitine appeared to depend on the intracellular concentration of methylglyoxal bis(guanylhydrazone), since the mitochondria-sparing effect disappeared at higher drug concentrations.

Cytosolic NADP(+)-dependent isocitrate dehydrogenase status modulates oxidative damage to cells.

PubMed

Lee, Su Min; Koh, Ho-Jin; Park, Dong-Chan; Song, Byoung J; Huh, Tae-Lin; Park, Jeen-Woo

2002-06-01

NADPH is an important cofactor in many biosynthesis pathways and the regeneration of reduced glutathione, critically important in cellular defense against oxidative damage. It is mainly produced by glucose 6-phosphate dehydrogenase (G6PD), malic enzyme, and the cytosolic form of NADP(+)-dependent isocitrate dehydrogenase (IDPc). Little information is available about the role of IDPc in antioxidant defense. In this study we investigated the role of IDPc against cytotoxicity induced by oxidative stress by comparing the relative degree of cellular responses in three different NIH3T3 cells with stable transfection with the cDNA for mouse IDPc in sense and antisense orientations, where IDPc activities were 3-4-fold higher and 35% lower, respectively, than that in the parental cells carrying the vector alone. Although the activities of other antioxidant enzymes, such as superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, and G6PD, were comparable in all transformed cells, the ratio of GSSG to total glutathione was significantly higher in the cells expressing the lower level of IDPc. This finding indicates that IDPc is essential for the efficient glutathione recycling. Upon transient exposure to increasing concentrations of H(2)O(2) or menadione, an intracellular source of free radicals and reactive oxygen species, the cells with low levels of IDPc became more sensitive to oxidative damage by H(2)O(2) or menadione. Lipid peroxidation, oxidative DNA damage, and intracellular peroxide generation were higher in the cell-line expressing the lower level of IDPc. However, the cells with the highly over-expressed IDPc exhibited enhanced resistance against oxidative stress, compared to the control cells. This study provides direct evidence correlating the activities of IDPc and the maintenance of the cellular redox state, suggesting that IDPc plays an important role in cellular defense against oxidative stress.

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

PubMed

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 Wiley Periodicals, Inc.

GSTP1 Loss Results in Accumulation of Oxidative DNA Base Damage and Promotes Prostate Cancer Cell Survival Following Exposure to Protracted Oxidative Stress

PubMed Central

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.

2016-01-01

BACKGROUND 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). METHODS 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. RESULTS 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. CONCLUSIONS 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. PMID:26447830

Edaravone protects osteoblastic cells from dexamethasone through inhibiting oxidative stress and mPTP opening.

PubMed

Sun, Wen-xiao; Zheng, Hai-ya; Lan, Jun

2015-11-01

Existing evidences have emphasized an important role of oxidative stress in dexamethasone (Dex)-induced osteoblastic cell damages. Here, we investigated the possible anti-Dex activity of edaravone in osteoblastic cells, and studied the underlying mechanisms. We showed that edaravone dose-dependently attenuated Dex-induced death and apoptosis of established human or murine osteoblastic cells. Further, Dex-mediated damages to primary murine osteoblasts were also alleviated by edaravone. In osteoblastic cells/osteoblasts, Dex induced significant oxidative stresses, tested by increased levels of reactive oxygen species and lipid peroxidation, which were remarkably inhibited by edaravone. Meanwhile, edaravone repressed Dex-induced mitochondrial permeability transition pore (mPTP) opening, or mitochondrial membrane potential reduction, in osteoblastic cells/osteoblasts. Significantly, edaravone-induced osteoblast-protective activity against Dex was alleviated with mPTP inhibition through cyclosporin A or cyclophilin-D siRNA. Together, we demonstrate that edaravone protects osteoblasts from Dex-induced damages probably through inhibiting oxidative stresses and following mPTP opening.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarwar, Tarique; Zafaryab, Md; Husain, Mohammed Amir

Ferulic acid (FA) is a plant polyphenol showing diverse therapeutic effects against cancer, diabetes, cardiovascular and neurodegenerative diseases. FA is a known antioxidant at lower concentrations, however at higher concentrations or in the presence of metal ions such as copper, it may act as a pro-oxidant. It has been reported that copper levels are significantly raised in different malignancies. Cancer cells are under increased oxidative stress as compared to normal cells. Certain therapeutic substances like polyphenols can further increase this oxidative stress and kill cancer cells without affecting the proliferation of normal cells. Through various in vitro experiments we havemore » shown that the pro-oxidant properties of FA are enhanced in the presence of copper. Comet assay demonstrated the ability of FA to cause oxidative DNA breakage in human peripheral lymphocytes which was ameliorated by specific copper-chelating agent such as neocuproine and scavengers of ROS. This suggested the mobilization of endogenous copper in ROS generation and consequent DNA damage. These results were further validated through cytotoxicity experiments involving different cell lines. Thus, we conclude that such a pro-oxidant mechanism involving endogenous copper better explains the anticancer activities of FA. This would be an alternate non-enzymatic, and copper-mediated pathway for the cytotoxic activities of FA where it can selectively target cancer cells with elevated levels of copper and ROS. - Highlights: • Pro-oxidant properties of ferulic acid are enhanced in presence of copper. • Ferulic acid causes oxidative DNA damage in lymphocytes as observed by comet assay. • DNA damage was ameliorated by copper chelating agent neocuproine and ROS scavengers. • Endogenous copper is involved in ROS generation causing DNA damage. • Ferulic acid exerts cancer cell specific cytotoxicity as observed by MTT assay.« less

Oxidative DNA damage induced by a hydroperoxide derivative of cyclophosphamide.

PubMed

Murata, Mariko; Suzuki, Toshinari; Midorikawa, Kaoru; Oikawa, Shinji; Kawanishi, Shosuke

2004-09-15

Interstrand DNA cross-linking has been considered to be the primary action mechanism of cyclophosphamide (CP) and its hydroperoxide derivative, 4-hydroperoxycyclophosphamide (4-HC). To clarify the mechanism of anti-tumor effects by 4-HC, we investigated DNA damage in a human leukemia cell line, HL-60, and its H(2)O(2)-resistant clone HP100. Apoptosis DNA ladder formation was detected in HL-60 cells treated with 4-HC, whereas it was not observed in HP100 cells. 4-HC significantly increased 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation, a marker of oxidative DNA damage, in HL-60 cells. On the other hand, CP did not significantly induce 8-oxodG formation and apoptosis in HL-60 cells under the same conditions as did 4-HC. Using (32)P-labeled DNA fragments from the human p53 tumor suppressor gene, 4-HC was found to cause Cu(II)-mediated oxidative DNA damage, but CP did not. Catalase inhibited 4-HC-induced DNA damage, including 8-oxodG formation, suggesting the involvement of H(2)O(2). The generation of H(2)O(2) during 4-HC degradation was ascertained by procedures using scopoletin and potassium iodide. We conclude that, in addition to DNA cross-linking, oxidative DNA damage through H(2)O(2) generation may participate in the anti-tumor effects of 4-HC.

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

PubMed

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.

Mangiferin attenuates oxidative stress induced renal cell damage through activation of PI3K induced Akt and Nrf-2 mediated signaling pathways.

PubMed

Saha, Sukanya; Sadhukhan, Pritam; Sinha, Krishnendu; Agarwal, Namrata; Sil, Parames C

2016-03-01

Mangiferin is a polyphenolic xanthonoid with remarkable antioxidant activity. Oxidative stress plays the key role in tert-butyl hydroperoxide (tBHP) induced renal cell damage. In this scenario, we consider mangiferin, as a safe agent in tBHP induced renal cell death and rationalize its action systematically, in normal human kidney epithelial cells (NKE). NKE cells were exposed to 20 µM mangiferin for 2 h followed by 50 µM tBHP for 18 h. The effect on endogenous ROS production, antioxidant status (antioxidant enzymes and thiols), mitochondrial membrane potential, apoptotic signaling molecules, PI3K mediated signaling cascades and cell cycle progression were examined using various biochemical assays, FACS and immunoblot analyses. tBHP exposure damaged the NKE cells and decreased its viability. It also elevated the intracellular ROS and other oxidative stress-related biomarkers within the cells. However, mangiferin dose dependently, exhibited significant protection against this oxidative cellular damage. Mangiferin inhibited tBHP induced activation of different pro-apoptotic signals and thus protected the renal cells against mitochondrial permeabilization. Further, mangiferin enhanced the expression of cell proliferative signaling cascade molecules, Cyclin d1, NFκB and antioxidant molecules HO-1, SOD2, by PI3K/Akt dependent pathway. However, the inhibitor of PI3K abolished mangiferin's protective activity. Results show Mangiferin maintains the intracellular anti-oxidant status, induces the expression of PI3K and its downstream molecules and shields NKE cells against the tBHP induced cytotoxicity. Mangiferin can be indicated as a therapeutic agent in oxidative stress-mediated renal toxicity. This protective action of mangiferin primarily attributes to its potent antioxidant and antiapoptotic nature.

Amelioration of oxidative DNA damage in mouse peritoneal macrophages by Hippophae salicifolia due to its proton (H+) donation capability: Ex vivo and in vivo studies

PubMed Central

Chakraborty, Mainak; Karmakar, Indrajit; Haldar, Sagnik; Das, Avratanu; Bala, Asis; Haldar, Pallab Kanti

2016-01-01

Introduction: The present study evaluates the antioxidant effect of methanol extract of Hippophae salicifolia (MEHS) bark with special emphasis on its role on oxidative DNA damage in mouse peritoneal macrophages. Material and Methods: In vitro antioxidant activity was estimated by standard antioxidant assays whereas the antioxidant activity concluded the H+ donating capacity. Mouse erythrocytes’ hemolysis and peritoneal macrophages’ DNA damage were determined spectrophotometrically. In vivo antioxidant activity of MEHS was determined in carbon tetrachloride-induced mice by studying its effect on superoxide anion production in macrophages cells, superoxide dismutase in the cell lysate, DNA damage, lipid peroxidation, and reduces glutathione. Results: The extract showed good in vitro antioxidant activities whereas the inhibitory concentrations values ranged from 5.80 to 106.5 μg/ml. MEHS significantly (P < 0.05) attenuated the oxidative DNA damage. It also attenuated the oxidative conversion of hemoglobin to methemoglobin and elevation of enzymatic and nonenzymatic antioxidant in cells. Conclusion: The result indicates MEHS has good in vitro-in vivo antioxidant property as well as the protective effect on DNA and red blood cell may be due to its H+ donating property. PMID:27413349

NEIL2 Protects against Oxidative DNA Damage Induced by Sidestream Smoke in Human Cells

PubMed Central

Sarker, Altaf H.; Chatterjee, Arpita; Williams, Monique; Lin, Sabrina; Havel, Christopher; Jacob III, Peyton; Boldogh, Istvan; Hazra, Tapas K.; Talbot, Prudence; Hang, Bo

2014-01-01

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. PMID:24595271

Nitric oxide ameliorates the damaging effects of oxidative stress induced by iron deficiency in cyanobacterium Anabaena 7120.

PubMed

Kaushik, Manish Singh; Srivastava, Meenakshi; Srivastava, Alka; Singh, Anumeha; Mishra, Arun Kumar

2016-11-01

In cyanobacterium Anabaena 7120, iron deficiency leads to oxidative stress with unavoidable consequences. Nitric oxide reduces pigment damage and supported the growth of Anabaena 7120 in iron-deficient conditions. Elevation in nitric oxide accumulation and reduced superoxide radical production justified the role of nitric oxide in alleviating oxidative stress in iron deficiency. Increased activities of antioxidative enzymes and higher levels of ROS scavengers (ascorbate, glutathione and thiol) in iron deficiency were also observed in the presence of nitric oxide. Nitric oxide also supported the membrane integrity of Anabaena cells and reduces protein and DNA damage caused by oxidative stress induced by iron deficiency. Results suggested that nitric oxide alleviates the damaging effects of oxidative stress induced by iron deficiency in cyanobacterium Anabaena 7120.

Predicting storage-dependent damage to red blood cells using nitrite oxidation kinetics, peroxiredoxin-2 oxidation, and hemoglobin and free heme measurements.

PubMed

Oh, Joo-Yeun; Stapley, Ryan; Harper, Victoria; Marques, Marisa B; Patel, Rakesh P

2015-12-01

Storage-dependent damage to red blood cells (RBCs) varies significantly. Identifying RBC units that will undergo higher levels of hemolysis during storage may allow for more efficient inventory management decision-making. Oxidative-stress mediates storage-dependent damage to RBCs and will depend on the oxidant:antioxidant balance. We reasoned that this balance or redox tone will serve as a determinant of how a given RBC unit stores and that its assessment in "young" RBCs will predict storage-dependent hemolysis. RBCs were sampled from bags and segments stored for 7 to 42 days. Redox tone was assessed by nitrite oxidation kinetics and peroxiredoxin-2 (Prx-2) oxidation. In parallel, hemolysis was assessed by measuring cell-free hemoglobin (Hb) and free heme (hemin). Correlation analyses were performed to determine if Day 7 measurements predicted either the level of hemolysis at Day 35 or the increase in hemolysis during storage. Higher Day 7 Prx-2 oxidation was associated with higher Day 35 Prx-2 oxidation, suggesting that early assessment of this variable may identify RBCs that will incur the most oxidative damage during storage. RBCs that oxidized nitrite faster on Day 7 were associated with the greatest levels of storage-dependent hemolysis and increases in Prx-2 oxidation. An inverse relationship between storage-dependent changes in oxyhemoglobin and free heme was observed underscoring an unappreciated reciprocity between these molecular species. Moreover, free heme was higher in the bag compared to paired segments, with opposite trends observed for free Hb. Measurement of Prx-2 oxidation and nitrite oxidation kinetics early during RBC storage may predict storage-dependent damage to RBC including hemolysis-dependent formation of free Hb and heme. © 2015 AABB.

Cellular defense against singlet oxygen-induced oxidative damage by cytosolic NADP+-dependent isocitrate dehydrogenase.

PubMed

Kim, Sun Yee; Park, Jeen-Woo

2003-03-01

Singlet oxygen (1O2) is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules. Recently, we have shown that NADP+-dependent isocitrate dehydrogenase is involved in the supply of NADPH needed for GSH production against cellular oxidative damage. In this study, we investigated the role of cytosolic form of NADP+-dependent isocitrate dehydrogenase (IDPc) against singlet oxygen-induced cytotoxicity by comparing the relative degree of cellular responses in three different NIH3T3 cells with stable transfection with the cDNA for mouse IDPc in sense and antisense orientations, where IDPc activities were 2.3-fold higher and 39% lower, respectively, than that in the parental cells carrying the vector alone. Upon exposure to singlet oxygen generated from photoactivated dye, the cells with low levels of IDPc became more sensitive to cell killing. Lipid peroxidation, protein oxidation, oxidative DNA damage and intracellular peroxide generation were higher in the cell-line expressing the lower level of IDPc. However, the cells with the highly over-expressed IDPc exhibited enhanced resistance against singlet oxygen, compared to the control cells. The data indicate that IDPc plays an important role in cellular defense against singlet oxygen-induced oxidative injury.

Increased oxidative phosphorylation in response to acute and chronic DNA damage

PubMed Central

Brace, Lear E; Vose, Sarah C; Stanya, Kristopher; Gathungu, Rose M; Marur, Vasant R; Longchamp, Alban; Treviño-Villarreal, Humberto; Mejia, Pedro; Vargas, Dorathy; Inouye, Karen; Bronson, Roderick T; Lee, Chih-Hao; Neilan, Edward; Kristal, Bruce S; Mitchell, James R

2016-01-01

Accumulation of DNA damage is intricately linked to aging, aging-related diseases and progeroid syndromes such as Cockayne syndrome (CS). Free radicals from endogenous oxidative energy metabolism can damage DNA, however the potential of acute or chronic DNA damage to modulate cellular and/or organismal energy metabolism remains largely unexplored. We modeled chronic endogenous genotoxic stress using a DNA repair-deficient Csa−/−|Xpa−/− mouse model of CS. Exogenous genotoxic stress was modeled in mice in vivo and primary cells in vitro treated with different genotoxins giving rise to diverse spectrums of lesions, including ultraviolet radiation, intrastrand crosslinking agents and ionizing radiation. Both chronic endogenous and acute exogenous genotoxic stress increased mitochondrial fatty acid oxidation (FAO) on the organismal level, manifested by increased oxygen consumption, reduced respiratory exchange ratio, progressive adipose loss and increased FAO in tissues ex vivo. In multiple primary cell types, the metabolic response to different genotoxins manifested as a cell-autonomous increase in oxidative phosphorylation (OXPHOS) subsequent to a transient decline in steady-state NAD+ and ATP levels, and required the DNA damage sensor PARP-1 and energy-sensing kinase AMPK. We conclude that increased FAO/OXPHOS is a general, beneficial, adaptive response to DNA damage on cellular and organismal levels, illustrating a fundamental link between genotoxic stress and energy metabolism driven by the energetic cost of DNA damage. Our study points to therapeutic opportunities to mitigate detrimental effects of DNA damage on primary cells in the context of radio/chemotherapy or progeroid syndromes. PMID:28721274

ATM directs DNA damage responses and proteostasis via genetically separable pathways

PubMed Central

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

2018-01-01

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. Here, we genetically separated DNA damage activation of ATM from oxidative activation using separation-of-function mutations. We found that deficiency in ATM activation by Mre11-Rad50-Nbs1 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 ATM lacking oxidative activation generates 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 implicates ATM in the control of protein homeostasis. PMID:29317520

Bisphenol A Promotes Cell Survival Following Oxidative DNA Damage in Mouse Fibroblasts

PubMed Central

Gassman, Natalie R.; Coskun, Erdem; Stefanick, Donna F.; Horton, Julie K.; Jaruga, Pawel; Dizdaroglu, Miral; Wilson, Samuel H.

2015-01-01

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. PMID:25693136

Measuring reactive species and oxidative damage in vivo and in cell culture: how should you do it and what do the results mean?

PubMed Central

Halliwell, Barry; Whiteman, Matthew

2004-01-01

Free radicals and other reactive species (RS) are thought to play an important role in many human diseases. Establishing their precise role requires the ability to measure them and the oxidative damage that they cause. This article first reviews what is meant by the terms free radical, RS, antioxidant, oxidative damage and oxidative stress. It then critically examines methods used to trap RS, including spin trapping and aromatic hydroxylation, with a particular emphasis on those methods applicable to human studies. Methods used to measure oxidative damage to DNA, lipids and proteins and methods used to detect RS in cell culture, especially the various fluorescent ‘probes' of RS, are also critically reviewed. The emphasis throughout is on the caution that is needed in applying these methods in view of possible errors and artifacts in interpreting the results. PMID:15155533

Endothelial and smooth muscle cells from abdominal aortic aneurysm have increased oxidative stress and telomere attrition.

PubMed

Cafueri, Giuseppe; Parodi, Federica; Pistorio, Angela; Bertolotto, Maria; Ventura, Francesco; Gambini, Claudio; Bianco, Paolo; Dallegri, Franco; Pistoia, Vito; Pezzolo, Annalisa; Palombo, Domenico

2012-01-01

Abdominal aortic aneurysm (AAA) is a complex multi-factorial disease with life-threatening complications. AAA is typically asymptomatic and its rupture is associated with high mortality rate. Both environmental and genetic risk factors are involved in AAA pathogenesis. Aim of this study was to investigate telomere length (TL) and oxidative DNA damage in paired blood lymphocytes, aortic endothelial cells (EC), vascular smooth muscle cells (VSMC), and epidermal cells from patients with AAA in comparison with matched controls. TL was assessed using a modification of quantitative (Q)-FISH in combination with immunofluorescence for CD31 or α-smooth muscle actin to detect EC and VSMC, respectively. Oxidative DNA damage was investigated by immunofluorescence staining for 7, 8-dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG). Telomeres were found to be significantly shortened in EC, VSMC, keratinocytes and blood lymphocytes from AAA patients compared to matched controls. 8-oxo-dG immunoreactivity, indicative of oxidative DNA damage, was detected at higher levels in all of the above cell types from AAA patients compared to matched controls. Increased DNA double strand breaks were detected in AAA patients vs controls by nuclear staining for γ-H2AX histone. There was statistically significant inverse correlation between TL and accumulation of oxidative DNA damage in blood lymphocytes from AAA patients. This study shows for the first time that EC and VSMC from AAA have shortened telomeres and oxidative DNA damage. Similar findings were obtained with circulating lymphocytes and keratinocytes, indicating the systemic nature of the disease. Potential translational implications of these findings are discussed.

Dysregulation of mitochondrial calcium signaling and superoxide flashes cause mitochondrial genomic DNA damage in Huntington disease.

PubMed

Wang, Jiu-Qiang; Chen, Qian; Wang, Xianhua; Wang, Qiao-Chu; Wang, Yun; Cheng, He-Ping; Guo, Caixia; Sun, Qinmiao; Chen, Quan; Tang, Tie-Shan

2013-02-01

Huntington disease (HD) is an inherited, fatal neurodegenerative disorder characterized by the progressive loss of striatal medium spiny neurons. Indications of oxidative stress are apparent in brain tissues from both HD patients and HD mouse models; however, the origin of this oxidant stress remains a mystery. Here, we used a yeast artificial chromosome transgenic mouse model of HD (YAC128) to investigate the potential connections between dysregulation of cytosolic Ca(2+) signaling and mitochondrial oxidative damage in HD cells. We found that YAC128 mouse embryonic fibroblasts exhibit a strikingly higher level of mitochondrial matrix Ca(2+) loading and elevated superoxide generation compared with WT cells, indicating that both mitochondrial Ca(2+) signaling and superoxide generation are dysregulated in HD cells. The excessive mitochondrial oxidant stress is critically dependent on mitochondrial Ca(2+) loading in HD cells, because blocking mitochondrial Ca(2+) uptake abolished elevated superoxide generation. Similar results were obtained using neurons from HD model mice and fibroblast cells from HD patients. More importantly, mitochondrial Ca(2+) loading in HD cells caused a 2-fold higher level of mitochondrial genomic DNA (mtDNA) damage due to the excessive oxidant generation. This study provides strong evidence to support a new causal link between dysregulated mitochondrial Ca(2+) signaling, elevated mitochondrial oxidant stress, and mtDNA damage in HD. Our results also indicate that reducing mitochondrial Ca(2+) uptake could be a therapeutic strategy for HD.

Toxicity of nano- and micro-sized silver particles in human hepatocyte cell line L02

NASA Astrophysics Data System (ADS)

Liu, Pengpeng; Guan, Rongfa; Ye, Xingqian; Jiang, Jiaxin; Liu, Mingqi; Huang, Guangrong; Chen, Xiaoting

2011-07-01

Silver nanoparticles (Ag NPs) previously classified as antimicrobial agents have been widely used in consumers and industrial products, especially food storage material. Ag NPs used as antimicrobial agents may be found in liver. Thus, examination of the ability of Ag NPs to penetrate the liver is warranted. The aim of the study was to determine the optimal viability assay for using with Ag NPs in order to assess their toxicity to liver cells. For toxicity evaluations, cellular morphology, mitochondrial function (3-(4, 5-dimethylazol-2-yl)-2, 5-diphenyl-tetrazolium bromide, MTT assay), membrane leakage of lactate dehydrogenase (lactate dehydrogenase, LDH release assay), Oxidative stress markers (malonaldehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD)), DNA damage (single cell gel eletrophoresis, SCGE assay), and protein damage were assessed under control and exposed conditions (24 h of exposure). The results showed that mitochondrial function decreased significantly in cells exposed to Ag NPs at 25 μg·mL-1. LDH leakage significantly increased in cells exposed to Ag NPs (>= 25 μg mL-1) while micro-sized silver particles tested displayed LDH leakage only at higher doses (100 μg·mL-1). The microscopic studies demonstrated that nanoparticle-exposed cells at higher doses became abnormal in size, displaying cellular shrinkage, and an acquisition of an irregular shape. Due to toxicity of silver, further study conducted with reference to its oxidative stress. The results exhibited significant depletion of GSH level, increase in SOD levels and lead to lipid peroxidation, which suggested that cytotoxicity of Ag NPs in liver cells might be mediated through oxidative stress. The results demonstrates that Ag NPs lead to cellular morphological modifications, LDH leakage, mitochondrial dysfunction, and cause increased generation of ROS, depletion of GSH, lipid peroxidation, oxidative DNA damage and protein damage. Though the exact mechanism behind Ag NPs toxicity is suggested oxidative stress and lipid peroxidation playing an important role in Ag NPs elicited cell membrane disruption, DNA damage, protein damage and subsequent cell death. Our preliminary data suggest that oxidative stress might contribute to Ag NPs cytotoxicity. To reveal whether apoptosis involved in Ag NPs toxicity, further studies are underway.

Cell type-specific hypersensitivity to oxidative damage in CSB and XPA mice.

PubMed

de Waard, Harm; de Wit, Jan; Gorgels, Theo G M F; van den Aardweg, Gerard; Andressoo, Jaan Olle; Vermeij, Marcel; van Steeg, Harry; Hoeijmakers, Jan H J; van der Horst, Gijsbertus T J

2003-01-02

Mutations in the CSB gene cause Cockayne syndrome (CS), a rare inherited disorder, characterized by UV-sensitivity, severe neurodevelopmental and progeroid symptoms. CSB functions in the transcription-coupled repair (TCR) sub-pathway of nucleotide excision repair (NER), responsible for the removal of UV-induced and other helix-distorting lesions from the transcribed strand of active genes. Several lines of evidence support the notion that the CSB TCR defect extends to other non-NER type transcription-blocking lesions, notably various kinds of oxidative damage, which may provide an explanation for part of the severe CS phenotype. We used genetically defined mouse models to examine the relationship between the CSB defect and sensitivity to oxidative damage in different cell types and at the level of the intact organism. The main conclusions are: (1) CSB(-/-) mouse embryo fibroblasts (MEFs) exhibit a clear hypersensitivity to ionizing radiation, extending the findings in genetically heterogeneous human CSB fibroblasts to another species. (2) CSB(-/-) MEFs are highly sensitive to paraquat, strongly indicating that the increased cytotoxicity is due to oxidative damage. (3) The hypersenstivity is independent of genetic background and directly related to the CSB defect and is not observed in totally NER-deficient XPA MEFs. (4) Wild type embryonic stem (ES) cells display an increased sensitivity to ionizing radiation compared to fibroblasts. Surprisingly, the CSB deficiency has only a very minor additional effect on ES cell sensitivity to oxidative damage and is comparable to that of an XPA defect, indicating cell type-specific differences in the contribution of TCR and NER to cellular survival. (5) Similar to ES cells, CSB and XPA mice both display a minor sensitivity to whole-body X-ray exposure. This suggests that the response of an intact organism to radiation is largely determined by the sensitivity of stem cells, rather than differentiated cells. These findings establish the role of transcription-coupled repair in resistance to oxidative damage and reveal a cell- and organ-specific impact of this repair pathway to the clinical phenotype of CS and XP.

An investigation of the effects of MitoQ on human peripheral mononuclear cells.

PubMed

Marthandan, Shiva; Murphy, Michael P; Billett, Ellen; Barnett, Yvonne

2011-03-01

MitoQ is a ubiquinone derivative targeted to mitochondria which is known to have both antioxidant and anti-apoptotic properties within mammalian cells. Previous research has suggested that the age-related increase in oxidative DNA damage in T lymphocytes might contribute to their functional decline with age. This paper describes the impact of mitoQ on unchallenged or oxidatively challenged ex vivo human peripheral blood mononuclear cells from healthy 25-30 or 55-60 year old volunteers. When cells were challenged with hydrogen peroxide (H(2)O(2)), following mitoQ treatment (0.1-1.0 μM), the ratio of reduced to oxidized forms of glutathione increased, the levels of oxidative DNA damage decreased and there was an increase in the mitochondrial membrane potential. Low levels of mitoQ (0.1 or 0.25 μM) had no impact on endogenous DNA damage, whilst higher levels (0.5 and 1.0 μM) of mitoQ significantly reduced endogenous levels of DNA damage. The results of this investigation suggest that mitoQ may have anti-immunosenescent potential.

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

PubMed

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 <1 microm to 1 mm. An organic extract of BDS is both cytotoxic and genotoxic to normal human bronchial epithelial (NHBE) cells. Based on the oxidizing potential of BDS, we hypothesized that an organic extract of this particulate matter would (1) cause 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.

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

PubMed Central

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

2012-01-01

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 polyaromatic hydrocarbons in particulates ranging in size from <1μm to 1 mm. An organic extract of BDS is both cytotoxic and genotoxic to normal human bronchial epithelial (NHBE) cells. Based on the oxidizing potential of BDS, we hypothesized that an organic extract of this particulate matter would: 1) cause 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 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 (α-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 proteins may partially explain the extranuclear fluorescence that is detected when NHBE cells are treated with an organic extract of BDS. Overexpression of both α-hOGG1 and APE-1 proteins following treatment of NHBE cells with BSEE suggests that this mixture causes oxidative DNA damage. PMID:18685817

A role for MHR1, a gene required for mitochondrial genetic recombination, in the repair of damage spontaneously introduced in yeast mtDNA.

PubMed

Ling, F; Morioka, H; Ohtsuka, E; Shibata, T

2000-12-15

A nuclear recessive mutant in Saccharomyces cerevisiae, mhr1-1, is defective in mitochondrial genetic recombination at 30 degrees C and shows extensive vegetative petite induction by UV irradiation at 30 degrees C or when cultivated at a higher temperature (37 degrees C). It has been postulated that mitochondrial DNA (mtDNA) is oxidatively damaged by by-products of oxidative respiration. Since genetic recombination plays a critical role in DNA repair in various organisms, we tested the possibility that MHR1 plays a role in the repair of oxidatively damaged mtDNA using an enzyme assay. mtDNA isolated from cells grown under standard (aerobic) conditions contained a much higher level of DNA lesions compared with mtDNA isolated from anaerobically grown cells. Soon after a temperature shift from 30 to 37 degrees C the number of mtDNA lesions increased 2-fold in mhr1-1 mutant cells but not in MHR1 cells. Malonic acid, which decreased the oxidative stress in mitochondria, partially suppressed both petite induction and the temperature-induced increase in the amount of mtDNA damage in mhr1-1 cells at 37 degrees C. Thus, functional mitochondria require active MHR1, which keeps the extent of spontaneous oxidative damage in mtDNA within a tolerable level. These observations are consistent with MHR1 having a possible role in mtDNA repair.

Apn1 AP-endonuclease is essential for the repair of oxidatively damaged DNA bases in yeast frataxin-deficient cells.

PubMed

Lefevre, Sophie; Brossas, Caroline; Auchère, Françoise; Boggetto, Nicole; Camadro, Jean-Michel; Santos, Renata

2012-09-15

Frataxin deficiency results in mitochondrial dysfunction and oxidative stress and it is the cause of the hereditary neurodegenerative disease Friedreich ataxia (FA). Here, we present evidence that one of the pleiotropic effects of oxidative stress in frataxin-deficient yeast cells (Δyfh1 mutant) is damage to nuclear DNA and that repair requires the Apn1 AP-endonuclease of the base excision repair pathway. Major phenotypes of Δyfh1 cells are respiratory deficit, disturbed iron homeostasis and sensitivity to oxidants. These phenotypes are weak or absent under anaerobiosis. We show here that exposure of anaerobically grown Δyfh1 cells to oxygen leads to down-regulation of antioxidant defenses, increase in reactive oxygen species, delay in G1- and S-phases of the cell cycle and damage to mitochondrial and nuclear DNA. Nuclear DNA lesions in Δyfh1 cells are primarily caused by oxidized bases and single-strand breaks that can be detected 15-30 min after oxygen exposition. The Apn1 enzyme is essential for the repair of the DNA lesions in Δyfh1 cells. Compared with Δyfh1, the double Δyfh1Δapn1 mutant shows growth impairment, increased mutagenesis and extreme sensitivity to H(2)O(2). On the contrary, overexpression of the APN1 gene in Δyfh1 cells decreases spontaneous and induced mutagenesis. Our results show that frataxin deficiency in yeast cells leads to increased DNA base oxidation and requirement of Apn1 for repair, suggesting that DNA damage and repair could be important features in FA disease progression.

Ultraviolet Radiation-Induced Skin Aging: The Role of DNA Damage and Oxidative Stress in Epidermal Stem Cell Damage Mediated Skin Aging

PubMed Central

Panich, Uraiwan; Sittithumcharee, Gunya; Rathviboon, Natwarath

2016-01-01

Skin is the largest human organ. Skin continually reconstructs itself to ensure its viability, integrity, and ability to provide protection for the body. Some areas of skin are continuously exposed to a variety of environmental stressors that can inflict direct and indirect damage to skin cell DNA. Skin homeostasis is maintained by mesenchymal stem cells in inner layer dermis and epidermal stem cells (ESCs) in the outer layer epidermis. Reduction of skin stem cell number and function has been linked to impaired skin homeostasis (e.g., skin premature aging and skin cancers). Skin stem cells, with self-renewal capability and multipotency, are frequently affected by environment. Ultraviolet radiation (UVR), a major cause of stem cell DNA damage, can contribute to depletion of stem cells (ESCs and mesenchymal stem cells) and damage of stem cell niche, eventually leading to photoinduced skin aging. In this review, we discuss the role of UV-induced DNA damage and oxidative stress in the skin stem cell aging in order to gain insights into the pathogenesis and develop a way to reduce photoaging of skin cells. PMID:27148370

Development of HSPA1A promoter-driven luciferase reporter gene assays in human cells for assessing the oxidative damage induced by silver nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xin, Lili, E-mail: llxin@suda.edu.cn

The exponential increase in the total number of engineered nanoparticles in consumer products requires novel tools for rapid and cost-effective toxicology screening. In order to assess the oxidative damage induced by nanoparticles, toxicity test systems based on a human HSPA1A promoter-driven luciferase reporter in HepG2, LO2, A549, and HBE cells were established. After treated with heat shock and a group of silver nanoparticles (AgNPs) with different primary particle sizes, the cell viability, oxidative damage, and luciferase activity were determined. The time-dependent Ag{sup +} ions release from AgNPs in cell medium was also evaluated. Our results showed that heat shock producedmore » a strong time-dependent induction of relative luciferase activity in the four luciferase reporter cells. Surprisingly, at 4 h of recovery, the relative luciferase activity was > 98 × the control level in HepG2-luciferase cells. Exposure to different sizes of AgNPs resulted in activation of the HSPA1A promoter in a dose-dependent manner, even at low cytotoxic or non-cytotoxic doses. The smaller (5 nm) AgNPs were more potent in luciferase induction than the larger (50 and 75 nm) AgNPs. These results were generally in accordance with the oxidative damage indicated by malondialdehyde concentration, reactive oxygen species induction and glutathione depletion, and Ag{sup +} ions release in cell medium. Compared with the other three luciferase reporter cells, the luciferase signal in HepG2-luciferase cells is obviously more sensitive and stable. We conclude that the luciferase reporter cells, especially the HepG2-luciferase cells, could provide a valuable tool for rapid screening of the oxidative damage induced by AgNPs. - Highlights: • We established the stable HSPA1A promoter-driven luciferase reporter cells. • Silver nanoparticles induced dose-dependent increases in luciferase activity. • HSPA1A promoter activity is a sensitive and responsive indicator of oxidative stress. • HepG2-luciferase cells can be used to assess the toxicity of silver nanoparticles.« less

Clustered DNA damages induced in human hematopoietic cells by low doses of ionizing radiation

NASA Technical Reports Server (NTRS)

Sutherland, Betsy M.; Bennett, Paula V.; Cintron-Torres, Nela; Hada, Megumi; Trunk, John; Monteleone, Denise; Sutherland, John C.; Laval, Jacques; Stanislaus, Marisha; Gewirtz, Alan

2002-01-01

Ionizing radiation induces clusters of DNA damages--oxidized bases, abasic sites and strand breaks--on opposing strands within a few helical turns. Such damages have been postulated to be difficult to repair, as are double strand breaks (one type of cluster). We have shown that low doses of low and high linear energy transfer (LET) radiation induce such damage clusters in human cells. In human cells, DSB are about 30% of the total of complex damages, and the levels of DSBs and oxidized pyrimidine clusters are similar. The dose responses for cluster induction in cells can be described by a linear relationship, implying that even low doses of ionizing radiation can produce clustered damages. Studies are in progress to determine whether clusters can be produced by mechanisms other than ionizing radiation, as well as the levels of various cluster types formed by low and high LET radiation.

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

NASA Technical Reports Server (NTRS)

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.

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

PubMed

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.

Magnolol protects against oxidative stress-mediated neural cell damage by modulating mitochondrial dysfunction and PI3K/Akt signaling.

PubMed

Dong, Liqun; Zhou, Shu; Yang, Xiaohua; Chen, Qianming; He, Yang; Huang, Wen

2013-07-01

Magnolol, an orally available compound from Magnolia officinalis used widely in traditional herbal medicine against a variety of neuronal diseases, possesses potent antioxidant properties and protects the brain against oxidative damage. The aim of the work is to examine the protective mechanisms of magnolol on human neuroblastoma SH-SY5Y cells against apoptosis induced by the neurotoxin acrolein, which can cause neurodegenerative disorders by inducing oxidative stress. By investigating the effect of magnolol on neural cell damage induced by the neurotoxin acrolein, we found that magnolol pretreatment significantly attenuated acrolein-induced oxidative stress through inhibiting reactive oxygen species accumulation caused by intracellular glutathione depletion and nicotinamide adenine dinucleotide phosphate oxidase activation. We next examined the signaling cascade(s) involved in magnolol-mediated antiapoptotic effects. The results showed that acrolein induced SH-SY5Y cell apoptosis by activating mitochondria/caspase and MEK/ERK signaling pathways. Our findings provide the first evidence that magnolol protects SH-SY5Y cells against acrolein-induced oxidative stress and prolongs SH-SY5Y cell survival through regulating JNK/mitochondria/caspase, PI3K/MEK/ERK, and PI3K/Akt/FoxO1 signaling pathways.

Carnitine prevents the early mitochondrial damage induced by methylglyoxal bis(guanylhydrazone) in L1210 leukaemia cells.

PubMed Central

Nikula, P; Ruohola, H; Alhonen-Hongisto, L; Jänne, J

1985-01-01

We previously found that the anti-cancer drug methylglyoxal bis(guanylhydrazone) (mitoguazone) depresses carnitine-dependent oxidation of long-chain fatty acids in cultured mouse leukaemia cells [Nikula, Alhonen-Hongisto, Seppänen & Jänne (1984) Biochem. Biophys. Res. Commun. 120, 9-14]. We have now investigated whether carnitine also influences the development of the well-known mitochondrial damage produced by the drug in L1210 leukaemia cells. Palmitate oxidation was distinctly inhibited in tumour cells exposed to 5 microM-methylglyoxal bis(guanylhydrazone) for only 7 h. Electron-microscopic examination of the drug-exposed cells revealed that more than half of the mitochondria were severely damaged. Similar exposure of the leukaemia cells to the drug in the presence of carnitine not only abolished the inhibition of fatty acid oxidation but almost completely prevented the drug-induced mitochondrial damage. The protection provided by carnitine appeared to depend on the intracellular concentration of methylglyoxal bis(guanylhydrazone), since the mitochondria-sparing effect disappeared at higher drug concentrations. Images Fig. 1. PMID:3837667

Copper toxicity, oxidative stress, and antioxidant nutrients.

PubMed

Gaetke, Lisa M; Chow, Ching Kuang

2003-07-15

Copper (Cu) is an integral part of many important enzymes involved in a number of vital biological processes. Although normally bound to proteins, Cu may be released and become free to catalyze the formation of highly reactive hydroxyl radicals. Data obtained from in vitro and cell culture studies are largely supportive of Cu's capacity to initiate oxidative damage and interfere with important cellular events. Oxidative damage has been linked to chronic Cu-overload and/or exposure to excess Cu caused by accidents, occupational hazards, and environmental contamination. Additionally, Cu-induced oxidative damage has been implicated in disorders associated with abnormal Cu metabolism and neurodegenerative changes. Interestingly, a deficiency in dietary Cu also increases cellular susceptibility to oxidative damage. A number of nutrients have been shown to interact with Cu and alter its cellular effects. Vitamin E is generally protective against Cu-induced oxidative damage. While most in vitro or cell culture studies show that ascorbic acid aggravates Cu-induced oxidative damage, results obtained from available animal studies suggest that the compound is protective. High intakes of ascorbic acid and zinc may provide protection against Cu toxicity by preventing excess Cu uptake. Zinc also removes Cu from its binding site, where it may cause free radical formation. Beta-carotene, alpha-lipoic acid and polyphenols have also been shown to attenuate Cu-induced oxidative damage. Further studies are needed to better understand the cellular effects of this essential, but potentially toxic, trace mineral and its functional interaction with other nutrients.

Effect of radiation on red cell membrane and intracellular oxidative defense systems.

PubMed

Katz, D; Mazor, D; Dvilansky, A; Meyerstein, N

1996-03-01

Ionizing radiation is currently used for prevention of transfusion associated graft versus host disease (TAGVHD). As radiation damage is associated with the production of activated oxygen species, the aim of this study was to observe the immediate effect of ionizing radiation on red cell membrane and intracellular oxidative defense systems. Neonatal and iron deficiency (IDA) cells, known for their increased sensitivity to oxidative stress, were chosen and compared with normal cells. Irradiation was performed in doses of 1500 cGy, 3000 cGy and 5000 cGy. GSH and methemoglobin levels and the activity of different antioxidant enzymes, measured under optimal in vitro conditions, were preserved in all cells after irradiation. Only radiation at the highest does of 5000 cGy, caused significant potassium leakage in neonatal cells and insignificant increase in IDA cells. Thus, cells with increased sensitivity to oxidative stress are more susceptible to damage by ionizing radiation than normal cells.

A study of oxidative stress induced by non-thermal plasma-activated water for bacterial damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Qian; Ma, Ruonan; Tian, Ying

2013-05-20

Ar/O{sub 2} (2%) cold plasma microjet was used to create plasma-activated water (PAW). The disinfection efficacy of PAW against Staphylococcus aureus showed that PAW can effectively disinfect bacteria. Optical emission spectra and oxidation reduction potential results demonstrated the inactivation is attributed to oxidative stress induced by reactive oxygen species in PAW. Moreover, the results of X-ray photoelectron spectroscopy, atomic absorption spectrometry, and transmission electron microscopy suggested that the chemical state of cell surface, the integrity of cell membrane, as well as the cell internal components and structure were damaged by the oxidative stress.

Genome-wide map of Apn1 binding sites under oxidative stress in Saccharomyces cerevisiae.

PubMed

Morris, Lydia P; Conley, Andrew B; Degtyareva, Natalya; Jordan, I King; Doetsch, Paul W

2017-11-01

The DNA is cells is continuously exposed to reactive oxygen species resulting in toxic and mutagenic DNA damage. Although the repair of oxidative DNA damage occurs primarily through the base excision repair (BER) pathway, the nucleotide excision repair (NER) pathway processes some of the same lesions. In addition, damage tolerance mechanisms, such as recombination and translesion synthesis, enable cells to tolerate oxidative DNA damage, especially when BER and NER capacities are exceeded. Thus, disruption of BER alone or disruption of BER and NER in Saccharomyces cerevisiae leads to increased mutations as well as large-scale genomic rearrangements. Previous studies demonstrated that a particular region of chromosome II is susceptible to chronic oxidative stress-induced chromosomal rearrangements, suggesting the existence of DNA damage and/or DNA repair hotspots. Here we investigated the relationship between oxidative damage and genomic instability utilizing chromatin immunoprecipitation combined with DNA microarray technology to profile DNA repair sites along yeast chromosomes under different oxidative stress conditions. We targeted the major yeast AP endonuclease Apn1 as a representative BER protein. Our results indicate that Apn1 target sequences are enriched for cytosine and guanine nucleotides. We predict that BER protects these sites in the genome because guanines and cytosines are thought to be especially susceptible to oxidative attack, thereby preventing large-scale genome destabilization from chronic accumulation of DNA damage. Information from our studies should provide insight into how regional deployment of oxidative DNA damage management systems along chromosomes protects against large-scale rearrangements. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Protection against oxidative DNA damage and stress in human prostate by glutathione S-transferase P1

PubMed Central

Kanwal, Rajnee; Pandey, Mitali; Bhaskaran, Natarajan; MacLennan, Gregory T; Fu, Pingfu; Ponsky, Lee E; Gupta, Sanjay

2014-01-01

The pi-class glutathione S-transferase (GSTP1) actively protect cells from carcinogens and electrophilic compounds. Loss of GSTP1 expression via promoter hypermethylation is the most common epigenetic alteration observed in human prostate cancer. Silencing of GSTP1 can increase generation of reactive oxygen species (ROS) and DNA damage in cells. In this study we investigated whether loss of GSTP1 contributes to increased DNA damage that may predispose men to a higher risk of prostate cancer. We found significantly elevated (103%; P<0.0001) levels of 8-oxo-2′-deoxogunosine (8-OHdG), an oxidative DNA damage marker, in adenocarcinomas, compared to benign counterparts, which positively correlated (r=0.2) with loss of GSTP1 activity (34%; P<0.0001). Silencing of GSTP1 using siRNA approach in normal human prostate epithelial RWPE1 cells caused increased intracellular production of ROS and higher susceptibility of cells to H2O2-mediated oxidative stress. Additionally, human prostate carcinoma LNCaP cells, which contain a silenced GSTP1 gene, were genetically modified to constitutively express high levels of GSTP1. Induction of GSTP1 activity lowered endogenous ROS levels in LNCaP-pLPCX-GSTP1 cells, and when exposed to H2O2, these cells exhibited significantly reduced production of ROS and 8-OHdG levels, compared to vector control LNCaP-pLPCX cells. Furthermore, exposure of LNCaP cells to green tea polyphenols caused re-expression of GSTP1, which protected the cells from H2O2-mediated DNA damage through decreased ROS production compared to non-exposed cells. These results suggest that loss of GSTP1 expression in human prostate cells, a process that increases their susceptibility to oxidative stress-induced DNA damage, may be an important target for primary prevention of prostate cancer. PMID:22833520

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

PubMed

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.

Magnetic Hyperthermia and Oxidative Damage to DNA of Human Hepatocarcinoma Cells

PubMed Central

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.

2017-01-01

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(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. PMID:28468256

Identifying initial molecular targets of PDT: protein and lipid oxidation products

NASA Astrophysics Data System (ADS)

Oleinick, Nancy L.; Kim, Junhwan; Rodriguez, Myriam E.; Xue, Liang-yan; Kenney, Malcolm E.; Anderson, Vernon E.

2009-06-01

Photodynamic Therapy (PDT) generates singlet oxygen (1O2) which oxidizes biomolecules in the immediate vicinity of its formation. The phthalocyanine photosensitizer Pc 4 localizes to mitochondria and endoplasmic reticulum, and the primary targets of Pc 4-PDT are expected to be lipids and proteins of those membranes. The initial damage then causes apoptosis in cancer cells via the release of cytochrome c (Cyt-c) from mitochondria into the cytosol, followed by the activation of caspases. That damage also triggers the induction of autophagy, an attempt by the cells to eliminate damaged organelles, or when damage is too extensive, to promote cell death. Cyt-c is bound to the cytosolic side of the mitochondrial inner membrane through association with cardiolipin (CL), a phospholipid containing four unsaturated fatty acids and thus easily oxidized by 1O2 or by other oxidizing agents. Increasing evidence suggests that oxidation of CL loosens its association with Cyt-c, and that the peroxidase activity of Cyt-c can oxidize CL. In earlier studies of Cyt-c in homogeneous medium by MALDI-TOF-MS and LC-ESI-MS, we showed that 1O2 generated by Pc 4-PDT oxidized histidine, methionine, tryptophan, and unexpectedly phenylalanine but not tyrosine. Most of the oxidation products were known to be formed by other oxidizing agents, such as hydroxyl radical, superoxide radical anion, and peroxynitrite. However, two products of histidine were unique to 1O2 and may be useful for reporting the action of 1O2 in cells and tissues. These products, as well as CL oxidation products, have now been identified in liposomes and mitochondria after Pc 4-PDT. In mitochondria, the PDT dose-dependent oxidations can be related to specific changes in mitochondrial function, Bcl-2 photodamage, and Cyt-c release. Thus, the role of PDT-generated 1O2 in oxidizing Cyt-c and CL and the interplay between protein and lipid targets may be highly relevant to understanding one mechanism for cell killing by PDT.

Effects of tempol and redox-cycling nitroxides in models of oxidative stress

PubMed Central

Wilcox, Christopher S.

2010-01-01

Tempol is a redox cycling nitroxide that promotes the metabolism of many reactive oxygen species (ROS) and improves nitric oxide bioavailability. It has been studied extensively in animal models of oxidative stress. Tempol has been shown to preserve mitochondria against oxidative damage and improve tissue oxygenation. Tempol improved insulin responsiveness in models of diabetes mellitus and improved the dyslipidemia, reduced the weight gain and prevented diastolic dysfunction and heart failure in fat-fed models of the metabolic syndrome. Tempol protected many organs, including the heart and brain, from ischemia/reperfusion damage. Tempol prevented podocyte damage, glomerulosclerosis, proteinuria and progressive loss of renal function in models of salt and mineralocorticosteroid excess. It reduced brain or spinal cord damage after ischemia or trauma and exerted a spinal analgesic action. Tempol improved survival in several models of shock. It protected normal cells from radiation while maintaining radiation sensitivity of tumor cells. Its paradoxical pro-oxidant action in tumor cells accounted for a reduction in spontaneous tumor formation. Tempol was effective in some models of neurodegeneration. Thus, tempol has been effective in preventing several of the adverse consequences of oxidative stress and inflammation that underlie radiation damage and many of the diseases associated with aging. Indeed, tempol given from birth prolonged the life span of normal mice. However, presently tempol has been used only in human subjects as a topical agent to prevent radiation-induced alopecia. PMID:20153367

Genotoxic and oxidative effects induced on A549 cells by extract of PM10 collected in an electric steel plant.

PubMed

Cavallo, Delia; Ursini, Cinzia L; Maiello, Raffaele; Apostoli, Pietro; Catalani, Simona; Ciervo, Aureliano; Iavicoli, Sergio

2008-01-01

The present study was aimed at assessing the carcinogenic risk of occupational exposure to PM10 in electric steel plants. PM10 was collected on cellulose filter respectively outside (site 1) and inside (site 2) the furnace area, was measured, extracted and its metal content was analysed by ICP-MS. Cells were exposed for 30 min, 2 and 4 hours to extract of filter from each site diluted at 0.004, 0.008 and 0.02%. The direct/oxidative DNA damage caused by PM10 was evaluated on A549 cells by Fpg-modified comet assay, analysing Tail moment (TM) and comet percentage. Air samples contained 1.08 mg/m3 of PM10 in site 1 and 5.54 mg/m3in site 2 and different amounts of metals with higher levels of Zn, Al, Ni, Pb, Cd, Cr, Ba in site 2 and of Fe, Mn, Sb in site 1. In cells exposed for 2h to PM10 from both sites, an oxidative DNA damage was found concentrations of 0.008% and 0.02%. For site 2, a direct DNA damage at 0.02% was also found. After 4h a direct/oxidative DNA damage was detected at 0.02% for site 2 and an oxidative DNA damage for site 1. The results indicate a moderate DNA damage induction by used diluitions of PM10 extracts with higher extent for more polluted site 2. These findings show the suitability of this experimental model to evaluate early DNA damage induced by complex mixtures containing metals on target organ, suggesting its use to study biological effects of occupational exposure to such substances.

XPD localizes in mitochondria and protects the mitochondrial genome from oxidative DNA damage.

PubMed

Liu, Jing; Fang, Hongbo; Chi, Zhenfen; Wu, Zan; Wei, Di; Mo, Dongliang; Niu, Kaifeng; Balajee, Adayabalam S; Hei, Tom K; Nie, Linghu; Zhao, Yongliang

2015-06-23

Xeroderma pigmentosum group D (XPD/ERCC2) encodes an ATP-dependent helicase that plays essential roles in both transcription and nucleotide excision repair of nuclear DNA, however, whether or not XPD exerts similar functions in mitochondria remains elusive. In this study, we provide the first evidence that XPD is localized in the inner membrane of mitochondria, and cells under oxidative stress showed an enhanced recruitment of XPD into mitochondrial compartment. Furthermore, mitochondrial reactive oxygen species production and levels of oxidative stress-induced mitochondrial DNA (mtDNA) common deletion were significantly elevated, whereas capacity for oxidative damage repair of mtDNA was markedly reduced in both XPD-suppressed human osteosarcoma (U2OS) cells and XPD-deficient human fibroblasts. Immunoprecipitation-mass spectrometry analysis was used to identify interacting factor(s) with XPD and TUFM, a mitochondrial Tu translation elongation factor was detected to be physically interacted with XPD. Similar to the findings in XPD-deficient cells, mitochondrial common deletion and oxidative damage repair capacity in U2OS cells were found to be significantly altered after TUFM knock-down. Our findings clearly demonstrate that XPD plays crucial role(s) in protecting mitochondrial genome stability by facilitating an efficient repair of oxidative DNA damage in mitochondria. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Wild Raspberry Subjected to Simulated Gastrointestinal Digestion Improves the Protective Capacity against Ethyl Carbamate-Induced Oxidative Damage in Caco-2 Cells

PubMed Central

Chen, Wei; Xu, Yang; Zhang, Lingxia; Li, Ya; Zheng, Xiaodong

2016-01-01

Ethyl carbamate (EC), a probable human carcinogen, occurs widely in many fermented foods. Previous studies indicated that EC-induced cytotoxicity was associated with oxidative stress. Wild raspberries are rich in polyphenolic compounds, which possess potent antioxidant activity. This study was conducted to investigate the protective effect of wild raspberry extracts produced before (RE) and after in vitro simulated gastrointestinal digestion (RD) on EC-induced oxidative damage in Caco-2 cells. Our primary data showed that ethyl carbamate could result in cytotoxicity and genotoxicity in Caco-2 cells and raspberry extract after digestion (RD) may be more effective than that before digestion (RE) in attenuating toxicity caused by ethyl carbamate. Further investigation by fluorescence microscope revealed that RD may significantly ameliorate EC-induced oxidative damage by scavenging the overproduction of intracellular reactive oxygen species (ROS), maintaining mitochondrial function and preventing glutathione (GSH) depletion. In addition, HPLC-ESI-MS results showed that the contents of identified polyphenolic compounds (esculin, kaempferol O-hexoside, and pelargonidin O-hexoside) were remarkably increased after digestion, which might be related to the better protective effect of RD. Overall, our results demonstrated that raspberry extract undergoing simulated gastrointestinal digestion may improve the protective effect against EC-induced oxidative damage in Caco-2 cells. PMID:26788245

Antibiotic tigecycline enhances cisplatin activity against human hepatocellular carcinoma through inducing mitochondrial dysfunction and oxidative damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jun; Song, Meijun; Zhou, Mi

Targeting mitochondrial metabolism has been recently demonstrated to be a promising therapeutic strategy for the treatment of various cancer. In this work, we demonstrate that antibiotic tigecycline is selectively against hepatocellular carcinoma (HCC) through inducing mitochondrial dysfunction and oxidative damage. Tigecycline is more effective in inhibiting proliferation and inducing apoptosis of HCC than normal liver cells. Importantly, tigecycline significantly enhances the inhibitory effects of chemotherapeutic drug cisplatin in HCC in vitro and in vivo. Mechanistically, tigecycline specifically inhibits mitochondrial translation as shown by the decreased protein levels of Cox-1 and -2 but not Cox-4 or Grp78, and increased mRNA levels of Cox-1more » and -2 but not Cox-4 in HCC cells exposed to tigecycline. In addition, tigecycline significantly induces mitochondrial dysfunction in HCC cells via decreasing mitochondrial membrane potential, complex I and IV activities, mitochondrial respiration and ATP levels. Tigecycline also increases levels of mitochondrial superoxide, hydrogen peroxide and ROS levels. Consistent with oxidative stress, oxidative damage on DNA, protein and lipid are also observed in tigecycline-treated cells. Importantly, antioxidant N-acetyl-L-cysteine (NAC) reverses the effects of tigecycline, suggesting that oxidative stress is required for the action of tigecycline in HCC cells. We further show that HCC cells have higher level of mitochondrial biogenesis than normal liver cells which might explain the different sensitivity to tigecycline between HCC and normal liver cells. Our work is the first to demonstrate that tigecycline is a promising candidate for HCC treatment and highlight the therapeutic value of targeting mitochondrial metabolism in HCC. - Highlights: • Tigecycline selectively targets HCC in vitro and in vivo. • Tigecycline enhances HCC cell response to chemotherapeutic drug. • Tigecycline inhibits mitochondrial translation and functions in HCC cells. • Tigecycline induces oxidative stress and damage in HCC cells. • Mitochondrial biogenesis and respiration is higher in HCC than normal liver cells.« less

Quercitrin protects skin from UVB-induced oxidative damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Yuanqin; Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY; Li, Wenqi

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 oxidativemore » 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.« less

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

PubMed

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.

Nutrition and muscle catabolism in maintenance hemodialysis: does feeding make muscle cells selective self-eaters?

PubMed

Franch, Harold A

2009-01-01

Efforts to build muscle by increased protein feeding in hemodialysis patients have been thwarted by parallel increases in both muscle protein synthesis and degradation. The evidence suggests that muscle cells replace older proteins in response to feeding rather than using new proteins to drive muscle cell hypertrophy. This review presents the hypothesis that protein feeding provides an opportunity for muscle to accelerate proteolysis of proteins that have been damaged by oxidation, nitrosylation, and/or glycosylation and to replace damaged mitochondria that contribute to oxidative stress. Increases in proteolysis with feeding are driven by insulin resistance and the increased oxidative stress of mitochondrial respiration. Oxidized proteins and organelles are excellent substrates for degradation by the proteasome, macroautophagy, and chaperone-mediated autophagy: these systems of proteolysis seem to be activated by oxydatiative stress. Replacement of oxidized and other damaged proteins may be a benefit of protein feeding in hemodialysis, but alternative strategies, including exercise, will be required to build muscle.

Nutrition and Muscle Catabolism in Maintenance Hemodialysis: Does Feeding Make Muscle Cells Selective Self-Eaters?

PubMed Central

Franch, Harold A.

2009-01-01

Efforts to build muscle by increased protein feeding in hemodialysis patients have been thwarted by parallel increases in both muscle protein synthesis and degradation. The evidence suggests that muscle cells replace older proteins in response to feeding rather than using new proteins to drive muscle cell hypertrophy. This review presents the hypothesis that protein feeding provides an opportunity for muscle to accelerate proteolysis of proteins which have been damaged by oxidation, nitrosylation and/or glycosylation and to replace damaged mitochondria that contribute to oxidative stress. Increases in proteolysis with feeding are driven by insulin resistance and the increased oxidative stress of mitochondrial respiration. Oxidized proteins and organelles are excellent substrates for degradation by the proteasome, macroautophagy, and chaperone-mediated autophagy: these systems of proteolysis seem to be activated by oxydatiative stress. Replacement of oxidized and other damaged proteins may be a benefit of protein feeding in hemodialysis, but alternative strategies, including exercise, will be required to build muscle. PMID:19121779

Role of NADP+-dependent isocitrate dehydrogenase (NADP+-ICDH) on cellular defence against oxidative injury by gamma-rays.

PubMed

Lee, S H; Jo, S H; Lee, S M; Koh, H J; Song, H; Park, J W; Lee, W H; Huh, T L

2004-09-01

To investigate the regulation of NADPH-producing isocitrate dehydrogenase (ICDH) in cytosol (IDPc) and mitochondria (IDPm) upon gamma-ray irradiation, and the roles of IDPc and IDPm in the protection against cellular damage induced by gamma-ray irradiation. Changes of IDPc and IDPm proteins upon gamma-ray irradiation to NIH3T3 cells were analysed by immunoblotting. To increase or decrease the expression of IDPc or IDPm, NIH3T3 cells were stably transfected with mouse IDPc or IDPm cDNA in either the sense or the antisense direction. The transfected cells with either increased or decreased IDPc or IDPm were exposed to gamma-rays, and the levels of reactive oxygen species generation, protein oxidation and lipid peroxidation were measured. Both IDPc and IDPm activities were induced by gamma-ray in NIH3T3 cells. Cells with decreased expression of IDPc or IDPm had elevated reactive oxygen species generation, lipid peroxidation and protein oxidation. Conversely, overproduction of IDPc or IDPm protein partially protected the cells from oxidative damage induced by gamma-ray irradiation. The protective role of IDPc and IDPm against gamma-ray-induced cellular damage can be attributed to elevated NADPH, reducing equivalents needed for recycling reduced glutathione in the cytosol and mitochondria. Thus, a primary biological function of the ICDHs may be production of NADPH, which is a prerequisite for some cellular defence systems against oxidative damage.

The Role of Gap Junction Communication and Oxidative Stress in the Propagation of Toxic Effects among High-Dose α-Particle-Irradiated Human Cells

PubMed Central

Autsavapromporn, Narongchai; de Toledo, Sonia M.; Little, John B.; Jay-Gerin, Jean-Paul; Harris, Andrew L.; Azzam, Edouard I.

2011-01-01

We investigated the roles of gap junction communication and oxidative stress in modulating potentially lethal damage repair in human fibroblast cultures exposed to doses of α particles or γ rays that targeted all cells in the cultures. As expected, α particles were more effective than γ rays at inducing cell killing; further, holding γ-irradiated cells in the confluent state for several hours after irradiation promoted increased survival and decreased chromosomal damage. However, maintaining α-particle-irradiated cells in the confluent state for various times prior to subculture resulted in increased rather than decreased lethality and was associated with persistent DNA damage and increased protein oxidation and lipid peroxidation. Inhibiting gap junction communication with 18-α-glycyrrhetinic acid or by knockdown of connexin43, a constitutive protein of junctional channels in these cells, protected against the toxic effects in α-particle-irradiated cell cultures during confluent holding. Upregulation of antioxidant defense by ectopic overexpression of glutathione peroxidase protected against cell killing by α particles when cells were analyzed shortly after exposure. However, it did not attenuate the decrease in survival during confluent holding. Together, these findings indicate that the damaging effect of α particles results in oxidative stress, and the toxic effects in the hours after irradiation are amplified by intercellular communication, but the communicated molecule(s) is unlikely to be a substrate of glutathione peroxidase. PMID:21388278

Resveratrol protects against arsenic trioxide-induced oxidative damage through maintenance of glutathione homeostasis and inhibition of apoptotic progression

PubMed Central

Chen, Chengzhi; Jiang, Xuejun; Lai, Yanhao; Liu, Yuan; Zhang, Zunzhen

2014-01-01

Arsenic trioxide (As2O3) is commonly used to treat acute promyelocytic leukemia and solid tumors. However, the clinical application of the agent is limited by its cyto- and genotoxic effects on normal cells. Thus, relief of As2O3 toxicity in normal cells is essentially necessary for improvement of As2O3-mediated chemotherapy. In this study, we have identified a series of protective effects of resveratrol against As2O3-induced oxidative damage in normal human bronchial epithelial (HBE) cells. We showed that treatment of HBE cells with resveratrol significantly reduced cellular levels of DNA damage, chromosomal breakage and apoptosis induced by As2O3. The effect of resveratrol against DNA damage was associated with a decreased level of reactive oxygen species and lipid peroxidation in cells treated by As2O3, suggesting that resveratrol protects against As2O3 toxicity via a cellular anti-oxidative stress pathway. Further analysis of the roles of resveratrol demonstrated that it modulated biosynthesis, recycling and consumption of glutathione (GSH), thereby promoting GSH homeostasis in HBE cells treated by As2O3. This was further supported by results showing that resveratrol prevented an increase in the activities and levels of caspases, Fas, Fas-L and cytochrome c proteins induced by As2O3. Our study indicates that resveratrol relieves As2O3-induced oxidative damage in normal human lung cells via maintenance of GSH homeostasis and suppression of apoptosis. PMID:25339131

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muniz, Juan F.; McCauley, Linda; Scherer, J.

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 andmore » 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.« less

Genetic damage induced by organic extract of coke oven emissions on human bronchial epithelial cells.

PubMed

Zhai, Qingfeng; Duan, Huawei; Wang, Yadong; Huang, Chuanfeng; Niu, Yong; Dai, Yufei; Bin, Ping; Liu, Qingjun; Chen, Wen; Ma, Junxiang; Zheng, Yuxin

2012-08-01

Coke oven emissions are known as human carcinogen, which is a complex mixture of polycyclic aromatic hydrocarbon. In this study, we aimed to clarify the mechanism of action of coke oven emissions induced carcinogenesis and to identify biomarkers of early biological effects in a human bronchial epithelial cell line with CYP1A1 activity (HBE-CYP1A1). Particulate matter was collected in the oven area on glass filter, extracted and analyzed by GC/MS. DNA breaks and oxidative damage were evaluated by alkaline and endonucleases (FPG, hOGG1 and ENDO III)-modified comet assays. Cytotoxicity and chromosomal damage were assessed by the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. The cells were treated with organic extract of coke oven emissions (OE-COE) representing 5, 10, 20, 40μg/mL extract for 24h. We found that there was a dose-effect relationship between the OE-COE and the direct DNA damage presented by tail length, tail intensity and Olive tail moment in the comet assay. The presence of lesion-specific endonucleases in the assays increased DNA migration after OE-COE treatment when compared to those without enzymes, which indicated that OE-COE produced oxidative damage at the level of pyrimidine and purine bases. The dose-dependent increase of micronuclei, nucleoplasmic bridges and nuclear buds in exposed cells was significant, indicating chromosomal and genomic damage induced by OE-COE. Based on the cytotoxic biomarkers in CBMN-Cyt assay, OE-COE may inhibit nuclear division, interfere with apoptosis, or induce cell necrosis. This study indicates that OE-COE exposure can induce DNA breaks/oxidative damage and genomic instability in HBE-CYP1A1 cells. The FPG-comet assay appears more specific for detecting oxidative DNA damage induced by complex mixtures of genotoxic substances. Copyright © 2012 Elsevier Ltd. All rights reserved.

Reduction in plasma total homocysteine through increasing folate intake in healthy individuals is not associated with changes in measures of antioxidant activity or oxidant damage.

PubMed

Moat, S J; Hill, M H; McDowell, I F W; Pullin, C H; Ashfield-Watt, P A L; Clark, Z E; Whiting, J M; Newcombe, R G; Lewis, M J; Powers, H J

2003-03-01

Various mechanisms have been proposed to explain the association between plasma total homocysteine (tHcy) and risk of cardiovascular disease, including oxidative activity of homocysteine. To explore the putative role of reactive oxygen species in the association between plasma tHcy and risk of cardiovascular disease in healthy individuals. A double-blind, placebo-controlled crossover intervention to increase folate intake through diet (increased consumption of folate-rich foods) and supplement (400 micro g folic acid) was carried out in 126 healthy men and women. Measurements were made of antioxidant activity in red blood cells and plasma, and products of oxidant damage in plasma. Diet and supplement-based interventions led to an increase in measures of folate status and a reduction in plasma tHcy. This was not associated with any significant change in measures of antioxidant activity (plasma and red blood cell glutathione peroxidase activity and red blood cell superoxide dismutase activity) or oxidant damage (plasma malondialdehyde), although an improvement in plasma total antioxidant capacity just failed to reach significance. In healthy individuals lowering plasma tHcy does not have any functional implications regarding oxidative damage.

Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response

PubMed Central

Busch, Andrea W.U.; Montgomery, Beronda L.

2015-01-01

Tetrapyrroles are involved in light harvesting and light perception, electron-transfer reactions, and as co-factors for key enzymes and sensory proteins. Under conditions in which cells exhibit stress-induced imbalances of photosynthetic reactions, or light absorption exceeds the ability of the cell to use photoexcitation energy in synthesis reactions, redox imbalance can occur in photosynthetic cells. Such conditions can lead to the generation of reactive oxygen species (ROS) associated with alterations in tetrapyrrole homeostasis. ROS accumulation can result in cellular damage and detrimental effects on organismal fitness, or ROS molecules can serve as signals to induce a protective or damage-mitigating oxidative stress signaling response in cells. Induced oxidative stress responses include tetrapyrrole-dependent and -independent mechanisms for mitigating ROS generation and/or accumulation. Thus, tetrapyrroles can be contributors to oxidative stress, but are also essential in the oxidative stress response to protect cells by contributing to detoxification of ROS. In this review, we highlight the interconnection and interdependence of tetrapyrrole metabolism with the occurrence of oxidative stress and protective oxidative stress signaling responses in photosynthetic organisms. PMID:25618582

The Polyphenol Chlorogenic Acid Attenuates UVB-mediated Oxidative Stress in Human HaCaT Keratinocytes

PubMed Central

Cha, Ji Won; Piao, Mei Jing; Kim, Ki Cheon; Yao, Cheng Wen; Zheng, Jian; Kim, Seong Min; Hyun, Chang Lim; Ahn, Yong Seok; Hyun, Jin Won

2014-01-01

We investigated the protective effects of chlorogenic acid (CGA), a polyphenol compound, on oxidative damage induced by UVB exposure on human HaCaT cells. In a cell-free system, CGA scavenged 1,1-diphenyl-2-picrylhydrazyl radicals, superoxide anions, hydroxyl radicals, and intracellular reactive oxygen species (ROS) generated by hydrogen peroxide and ultraviolet B (UVB). Furthermore, CGA absorbed electromagnetic radiation in the UVB range (280–320 nm). UVB exposure resulted in damage to cellular DNA, as demonstrated in a comet assay; pre-treatment of cells with CGA prior to UVB irradiation prevented DNA damage and increased cell viability. Furthermore, CGA pre-treatment prevented or ameliorated apoptosis-related changes in UVB-exposed cells, including the formation of apoptotic bodies, disruption of mitochondrial membrane potential, and alterations in the levels of the apoptosis-related proteins Bcl-2, Bax, and caspase-3. Our findings suggest that CGA protects cells from oxidative stress induced by UVB radiation. PMID:24753819

Protective effects of total saponins from stem and leaf of Panax ginseng against cyclophosphamide-induced genotoxicity and apoptosis in mouse bone marrow cells and peripheral lymphocyte cells.

PubMed

Zhang, Qiu Hua; Wu, Chun Fu; Duan, Lian; Yang, Jing Yu

2008-01-01

Cyclophosphamide (CP), commonly used anti-cancer, induces oxidative stress and is cytotoxic to normal cells. It is very important to choice the protective agent combined CP to reduce the side effects in cancer treatment. Ginsenosides are biological active constituents of Panax ginseng C.A. Meyer that acts as the tonic agent for the cancer patients to reduce the side effects in the clinic application. Because CP is a pro-oxidant agent and induces oxidative stress by the generation of free radicals to decrease the activities of anti-oxidant enzymes, the protective effects of the total saponins from stem and leaf of P. ginseng C.A. Meyer (TSPG) act as an anti-oxidant agent against the decreased anti-oxidant enzymes, the genotoxicity and apoptosis induced by CP was carried out. The alkaline single cell gel electrophoresis was employed to detect DNA damage; flow cytometry assay and AO/EB staining assay were employed to measure cell apoptosis; the enzymatic anti-oxidants (T-SOD, CAT and GPx) and non-enzymatic anti-oxidant (GSH) were measured by the various colorimetric methods. CP induced the significant DNA damage in mouse peripheral lymphocytes in time- and dose-dependent manners, inhibited the activities of T-SOD, GPx and CAT, and decreased the contents of GSH in mouse blood, triggered bone marrow cell apoptosis at 6 and 12h. TSPG significantly reduced CP-induced DNA damages in bone marrow cells and peripheral lymphocyte cells, antagonized CP-induced reduction of T-SOD, GPx, CAT activities and the GSH contents, decreased the bone marrow cell apoptosis induced by CP. TSPG, significantly reduced the genotoxicity of CP in bone marrow cells and peripheral lymphocyte cells, and decreased the apoptotic cell number induced by CP in bone marrow cells. The effects of TSPG on T-SOD, GPx, CAT activities and GSH contents might partially contribute to its protective effects on CP-induced cell toxicities.

The Role of Pyruvate in Protecting 661W Photoreceptor-Like Cells Against Light-Induced Cell Death.

PubMed

Natoli, Riccardo; Rutar, Matt; Lu, Yen-Zhen; Chu-Tan, Joshua A; Chen, Yuwei; Saxena, Kartik; Madigan, Michele; Valter, Krisztina; Provis, Jan M

2016-11-01

Light is a requirement for the function of photoreceptors in visual processing. However, prolonged light exposure can be toxic to photoreceptors, leading to increased reactive oxygen species (ROS), lipid peroxidation, and photoreceptor cell death. We used the 661W mouse cone photoreceptor-like cell line to study the effects of pyruvate in protecting these cells from light-induced toxicity. 661W cells were exposed to 15,000 lux continuous bright light for 5 hours and incubated in Dulbecco's modified eagle medium (DMEM) with various concentrations of pyruvate. Following light damage, cells were assessed for changes in morphology, cell toxicity, viability, and ROS production. Mitochondrial respiration and anaerobic glycolysis were also assessed using a Seahorse Xfe96 extracellular flux analyzer. We found that cell death caused by light damage in 661W cells was dramatically reduced in the presence of pyruvate. Cells with pyruvate-supplemented media also showed attenuation of oxidative stress and maintained normal levels of ATP. We also found that alterations in the concentrations of pyruvate had no effect on mitochondrial respiration or glycolysis in light-damaged cells. Taken together, the results show that pyruvate is protective against light damage but does not alter the metabolic output of the cells, indicating an alternative role for pyruvate in reducing oxidative stress. Thus, sodium pyruvate is a possible candidate for the treatment against the oxidative stress component of retinal degenerations.

Nitric oxide alleviates oxidative damage induced by enhanced ultraviolet-B radiation in cyanobacterium.

PubMed

Xue, Lingui; Li, Shiweng; Sheng, Hongmei; Feng, Huyuan; Xu, Shijian; An, Lizhe

2007-10-01

To study the role of nitric oxide (NO) on enhanced ultraviolet-B (UV-B) radiation (280-320 nm)-induced damage of Cyanobacterium, the growth, pigment content, and antioxidative activity of Spirulina platensis-794 cells were investigated under enhanced UV-B radiation and under different chemical treatments with or without UV-B radiation for 6 h. The changes in chlorophyll-a, malondialdehyde content, and biomass confirmed that 0.5 mM: sodium nitroprusside (SNP), a donor of nitric oxide (NO), could markedly alleviate the damage caused by enhanced UV-B. Specifically, the biomass and the chlorophyll-a content in S. platensis-794 cells decreased 40% and 42%, respectively under enhanced UV-B stress alone, but they only decreased 10% and 18% in the cells treated with UV-B irradiation and 0.5 mM: SNP. Further experiments suggested that NO treatment significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT), and decreased the accumulation of O (2)(-) in enhanced UV-B-irradiated cells. SOD and CAT activity increased 0.95- and 6.73-fold, respectively. The accumulation of reduced glutathione (GSH) increased during treatment with 0.5 mM: SNP in normal S. platensis cells, but SNP treatment could inhibit the increase of GSH in enhanced UV-B-stressed S. platensis cells. Thus, these results suggest that NO can strongly alleviate oxidative damage caused by UV-B stress by increasing the activities of SOD, peroxidase, CAT, and the accumulation of GSH, and by eliminating O (2)(-) in S. platensis-794 cells. In addition, the difference of NO origin between plants and cyanobacteria are discussed.

HPV16 E6 and E7 proteins induce a chronic oxidative stress response via NOX2 that causes genomic instability and increased susceptibility to DNA damage in head and neck cancer cells

PubMed Central

Marullo, Rossella; Werner, Erica; Zhang, Hongzheng; Chen, Georgia Z.; Shin, Dong M.; Doetsch, Paul W.

2015-01-01

Human papillomavirus (HPV) is the causative agent of a subgroup of head and neck cancer characterized by an intrinsic radiosensitivity. HPV initiates cellular transformation through the activity of E6 and E7 proteins. E6 and E7 expression is necessary but not sufficient to transform the host cell, as genomic instability is required to acquire the malignant phenotype in HPV-initiated cells. This study reveals a key role played by oxidative stress in promoting genomic instability and radiosensitivity in HPV-positive head and neck cancer. By employing an isogenic human cell model, we observed that expression of E6 and E7 is sufficient to induce reactive oxygen species (ROS) generation in head and neck cancer cells. E6/E7-induced oxidative stress is mediated by nicotinamide adenine dinucleotide phosphate oxidases (NOXs) and causes DNA damage and chromosomal aberrations. This mechanism for genomic instability distinguishes HPV-positive from HPV-negative tumors, as we observed NOX-induced oxidative stress in HPV-positive but not HPV-negative head and neck cancer cells. We identified NOX2 as the source of HPV-induced oxidative stress as NOX2 silencing significantly reduced ROS generation, DNA damage and chromosomal aberrations in HPV-positive cells. Due to their state of chronic oxidative stress, HPV-positive cells are more susceptible to DNA damage induced by ROS and ionizing radiation (IR). Furthermore, exposure to IR results in the formation of complex lesions in HPV-positive cells as indicated by the higher amount of chromosomal breakage observed in this group of cells. These results reveal a novel mechanism for sustaining genomic instability in HPV-positive head and neck tumors and elucidate its contribution to their intrinsic radiosensitivity. PMID:26354779

Protective Role of Nuclear Factor E2-Related Factor 2 against Acute Oxidative Stress-Induced Pancreatic β-Cell Damage

PubMed Central

Fu, Jingqi; Zheng, Hongzhi; Wang, Huihui; Yang, Bei; Zhao, Rui; Lu, Chunwei; Liu, Zhiyuan; Hou, Yongyong; Xu, Yuanyuan; Zhang, Qiang; Qu, Weidong; Pi, Jingbo

2015-01-01

Oxidative stress is implicated in the pathogenesis of pancreatic β-cell dysfunction that occurs in both type 1 and type 2 diabetes. Nuclear factor E2-related factor 2 (NRF2) is a master regulator in the cellular adaptive response to oxidative stress. The present study found that MIN6 β-cells with stable knockdown of Nrf2 (Nrf2-KD) and islets isolated from Nrf2-knockout mice expressed substantially reduced levels of antioxidant enzymes in response to a variety of stressors. In scramble MIN6 cells or wild-type islets, acute exposure to oxidative stressors, including hydrogen peroxide (H2O2) and S-nitroso-N-acetylpenicillamine, resulted in cell damage as determined by decrease in cell viability, reduced ATP content, morphology changes of islets, and/or alterations of apoptotic biomarkers in a concentration- and/or time-dependent manner. In contrast, silencing of Nrf2 sensitized MIN6 cells or islets to the damage. In addition, pretreatment of MIN6 β-cells with NRF2 activators, including CDDO-Im, dimethyl fumarate (DMF), and tert-butylhydroquinone (tBHQ), protected the cells from high levels of H2O2-induced cell damage. Given that reactive oxygen species (ROS) are involved in regulating glucose-stimulated insulin secretion (GSIS) and persistent activation of NRF2 blunts glucose-triggered ROS signaling and GSIS, the present study highlights the distinct roles that NRF2 may play in pancreatic β-cell dysfunction that occurs in different stages of diabetes. PMID:25949772

Oxidant-induced DNA damage of target cells.

PubMed Central

Schraufstätter, I; Hyslop, P A; Jackson, J H; Cochrane, C G

1988-01-01

In this study we examined the leukocytic oxidant species that induce oxidant damage of DNA in whole cells. H2O2 added extracellularly in micromolar concentrations (10-100 microM) induced DNA strand breaks in various target cells. The sensitivity of a specific target cell was inversely correlated to its catalase content and the rate of removal of H2O2 by the target cell. Oxidant species produced by xanthine oxidase/purine or phorbol myristate acetate-stimulated monocytes induced DNA breakage of target cells in proportion to the amount of H2O2 generated. These DNA strand breaks were prevented by extracellular catalase, but not by superoxide dismutase. Cytotoxic doses of HOCl, added to target cells, did not induce DNA strand breakage, and myeloperoxidase added extracellularly in the presence of an H2O2-generating system, prevented the formation of DNA strand breaks in proportion to its H2O2 degrading capacity. The studies also indicated that H2O2 formed hydroxyl radical (.OH) intracellularly, which appeared to be the most likely free radical responsible for DNA damage: .OH was detected in cells exposed to H2O2; the DNA base, deoxyguanosine, was hydroxylated in cells exposed to H2O2; and intracellular iron was essential for induction of DNA strand breaks. PMID:2843565

5-s-Cysteinyl-conjugates of catecholamines induce cell damage, extensive DNA base modification and increases in caspase-3 activity in neurons.

PubMed

Spencer, Jeremy P E; Whiteman, Matthew; Jenner, Peter; Halliwell, Barry

2002-04-01

A decrease in reduced glutathione levels in dopamine containing nigral cells in Parkinson's disease may result from the formation of cysteinyl-adducts of catecholamines, which in turn exert toxicity on nigral cells. We show that exposure of neurons (CSM 14.1) to 5-S-cysteinyl conjugates of dopamine, L-DOPA, DOPAC or DHMA causes neuronal damage, increases in oxidative DNA base modification and an elevation of caspase-3 activity in cells. Damage to neurons was apparent 12-48 h of post-exposure and there were increases in caspase-3 activity in neurons after 6 h. These changes were paralleled by large increases in pyrimidine and purine base oxidation products, such as 8-OH-guanine suggesting that 5-S-cysteinyl conjugates of catecholamines are capable of diffusing into cells and stimulating the formation of reactive oxygen species (ROS), which may then lead to a mechanism of cell damage involving caspase-3. Indeed, intracellular ROS were observed to rise sharply on exposure to the conjugates. These results suggest one mechanism by which oxidative stress may occur in the substantia nigra in Parkinson's disease.

Oxidative Damage and Cellular Defense Mechanisms in Sea Urchin Models of Aging

PubMed Central

Du, Colin; Anderson, Arielle; Lortie, Mae; Parsons, Rachel; Bodnar, Andrea

2013-01-01

The free radical or oxidative stress theory of aging proposes that the accumulation of oxidative cellular damage is a major contributor to the aging process and a key determinant of species longevity. This study investigates the oxidative stress theory in a novel model for aging research, the sea urchin. Sea urchins present a unique model for the study of aging due to the existence of species with tremendously different natural life spans including some species with extraordinary longevity and negligible senescence. Cellular oxidative damage, antioxidant capacity and proteasome enzyme activities were measured in the tissues of three sea urchin species: short-lived Lytechinus variegatus, long-lived Strongylocentrotus franciscanus and Strongylocentrotus purpuratus which has an intermediate lifespan. Levels of protein carbonyls and 4-hydroxynonenal (HNE) measured in tissues (muscle, nerve, esophagus, gonad, coelomocytes, ampullae) and 8-hydroxy-2’-deoxyguanosine (8-OHdG) measured in cell-free coelomic fluid showed no general increase with age. The fluorescent age-pigment lipofuscin measured in muscle, nerve and esophagus, increased with age however it appeared to be predominantly extracellular. Antioxidant mechanisms (total antioxidant capacity, superoxide dismutase) and proteasome enzyme activities were maintained with age. In some instances, levels of oxidative damage were lower and antioxidant activity higher in cells or tissues of the long-lived species compared to the short-lived species, however further studies are required to determine the relationship between oxidative damage and longevity in these animals. Consistent with the predictions of the oxidative stress theory of aging, the results suggest that negligible senescence is accompanied by a lack of accumulation of cellular oxidative damage with age and maintenance of antioxidant capacity and proteasome enzyme activities may be important mechanisms to mitigate damage. PMID:23707327

Oxidative damage and cellular defense mechanisms in sea urchin models of aging.

PubMed

Du, Colin; Anderson, Arielle; Lortie, Mae; Parsons, Rachel; Bodnar, Andrea

2013-10-01

The free radical, or oxidative stress, theory of aging proposes that the accumulation of oxidative cellular damage is a major contributor to the aging process and a key determinant of species longevity. This study investigates the oxidative stress theory in a novel model for aging research, the sea urchin. Sea urchins present a unique model for the study of aging because of the existence of species with tremendously different natural life spans, including some species with extraordinary longevity and negligible senescence. Cellular oxidative damage, antioxidant capacity, and proteasome enzyme activities were measured in the tissues of three sea urchin species: short-lived Lytechinus variegatus, long-lived Strongylocentrotus franciscanus, and Strongylocentrotus purpuratus, which has an intermediate life span. Levels of protein carbonyls and 4-hydroxynonenal measured in tissues (muscle, nerve, esophagus, gonad, coelomocytes, ampullae) and 8-hydroxy-2'-deoxyguanosine measured in cell-free coelomic fluid showed no general increase with age. The fluorescent age pigment lipofuscin, measured in muscle, nerve, and esophagus, increased with age; however, it appeared to be predominantly extracellular. Antioxidant mechanisms (total antioxidant capacity, superoxide dismutase) and proteasome enzyme activities were maintained with age. In some instances, levels of oxidative damage were lower and antioxidant activity higher in cells or tissues of the long-lived species compared to the short-lived species; however, further studies are required to determine the relationship between oxidative damage and longevity in these animals. Consistent with the predictions of the oxidative stress theory of aging, the results suggest that negligible senescence is accompanied by a lack of accumulation of cellular oxidative damage with age, and maintenance of antioxidant capacity and proteasome enzyme activities may be important mechanisms to mitigate damage. Copyright © 2013 Elsevier Inc. All rights reserved.

Low molecular weight guluronate prevents TNF-α-induced oxidative damage and mitochondrial dysfunction in C2C12 skeletal muscle cells.

PubMed

Dun, Yun-lou; Zhou, Xiao-lin; Guan, Hua-shi; Yu, Guang-li; Li, Chun-xia; Hu, Ting; Zhao, Xia; Cheng, Xiao-lei; He, Xiao-xi; Hao, Jie-jie

2015-09-01

Muscle wasting is associated with a variety of chronic or inflammatory disorders. Evidence suggests that inflammatory cytokines play a vital role in muscle inflammatory pathology and this may result in oxidative damage and mitochondrial dysfunction in skeletal muscle. In our study, we used microwave degradation to prepare a water-soluble low molecular weight guluronate (LMG) of 3000 Da from Fucus vesiculosus obtained from Canada, the Atlantic Ocean. We demonstrated the structural characteristics, using HPLC, FTIR and NMR of LMG and investigated its effects on oxidative damage and mitochondrial dysfunction in C2C12 skeletal muscle cells induced by tumor necrosis factor alpha (TNF-α), a cell inflammatory cytokine. The results indicated that LMG could alleviate mitochondrial reactive oxygen species (ROS) production, increase the activities of antioxidant enzymes (GSH and SOD), promote mitochondrial membrane potential (MMP) and upregulate the expression of mitochondrial respiratory chain protein in TNF-α-induced C2C12 cells. LMG supplement also increased the mitochondrial DNA copy number and mitochondrial biogenesis related genes in TNF-α-induced C2C12 cells. LMG may exert these protective effects through the nuclear factor kappa B (NF-κB) signaling pathway. These suggest that LMG is capable of protecting TNF-α-induced C2C12 cells against oxidative damage and mitochondrial dysfunction.

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

PubMed Central

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

2016-01-01

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. PMID:27166647

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

PubMed

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.

Knockdown of cytosolic NADP(+) -dependent isocitrate dehydrogenase enhances MPP(+) -induced oxidative injury in PC12 cells.

PubMed

Yang, Eun Sun; Park, Jeen-Woo

2011-05-01

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its toxic metabolite 1-methyl-4-phenylpyridium ion (MPP(+)) have been shown to induce Parkinson's disease-like symptoms as well as neurotoxicity in humans and animal species. Recently, we reported that maintenance of redox balance and cellular defense against oxidative damage are primary functions of the novel antioxidant enzyme cytosolic NADP(+) -dependent isocitrate dehydrogenase (IDPc). In this study, we examined the role of IDPc in cellular defense against MPP(+) -induced oxidative injury using PC12 cells transfected with IDPc small interfering RNA (siRNA). Our results demonstrate that MPP(+) -mediated disruption of cellular redox status, oxidative damage to cells, and apoptotic cell death were significantly enhanced by knockdown of IDPc.

Prophylaxis with Bacopa monnieri attenuates acrylamide induced neurotoxicity and oxidative damage via elevated antioxidant function.

PubMed

Shinomol, George Kunnel; Raghunath, Narayanareddy; Bharath, Muchukunte Mukunda Srinivas; Muralidhara

2013-03-01

Acrylamide (ACR) is a water-soluble, vinyl monomer that has multiple chemical and industrial applications. Exposure to ACR causes neuropathy and associated neurological defects including gait abnormalities and skeletal muscle weakness, due to impaired neurotransmitter release and eventual neurodegeneration. Using in vivo and in vitro models, we examined whether oxidative events are involved in ACR-mediated neurotoxicity and whether these could be prevented by natural plant extracts. Administration (i.p.) of ACR in mice (40 mg/kg bw/ d for 5d) induced significant oxidative damage in the brain cortex and liver as evidenced by elevated lipid peroxidation, reactive oxygen species and protein carbonyls. This was associated with lowered antioxidant activities including antioxidant enzymes (catalase, glutathione-s-transferase) and reduced glutathione (GSH) compared to untreated controls. Similarly, exposure of N27 neuronal cells in culture to ACR (1-5 mM) caused dose-dependent neuronal death and lowered GSH. Interestingly, dietary supplementation with the leaf powder of Bacopa monnieri (BM) (which possesses neuroprotective properties and nootropic activity) in mice for 30 days offered significant protection against ACR toxicity and oxidative damage in vivo. Similarly, pretreatment with BM protected the N27 cells against ACR-induced cell death and associated oxidative damage. Co-treatment and pre-treatment of Drosophila melanogaster with BM extract protected against ACR-induced locomotor dysfunction and GSH depletion. We infer that BM displays prophylactic effects against ACR induced oxidative damage and neurotoxicity with potential therapeutic application in human pathology associated with neuropathy.

Autophagy protects gastric mucosal epithelial cells from ethanol-induced oxidative damage via mTOR signaling pathway

PubMed Central

Chang, Weilong; Bai, Jie; Tian, Shaobo; Ma, Muyuan; Li, Wei; Yin, Yuping; Deng, Rui; Cui, Jinyuan; Li, Jinjin; Wang, Guobin; Tao, Kaixiong

2017-01-01

Alcohol abuse is an important cause of gastric mucosal epithelial cell injury and gastric ulcers. A number of studies have demonstrated that autophagy, an evolutionarily conserved cellular mechanism, has a protective effect on cell survival. However, it is not known whether autophagy can protect gastric mucosal epithelial cells against the toxic effects of ethanol. In the present study, gastric mucosal epithelial cells (GES-1 cells) and Wistar rats were treated with ethanol to detect the adaptive response of autophagy. Our results demonstrated that ethanol exposure induced gastric mucosal epithelial cell damage, which was accompanied by the downregulation of mTOR signaling pathway and activation of autophagy. Suppression of autophagy with pharmacological agents resulted in a significant increase of GES-1 cell apoptosis and gastric mucosa injury, suggesting that autophagy could protect cells from ethanol toxicity. Furthermore, we evaluated the cellular oxidative stress response following ethanol treatment and found that autophagy induced by ethanol inhibited generation of reactive oxygen species and degradation of antioxidant and lipid peroxidation. In conclusion, these findings provide evidence that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate oxidative damage induced by ethanol in gastric mucosal epithelial cells. Therefore, modifying autophagy may provide a therapeutic strategy against alcoholic gastric mucosa injury. Impact statement The effect and mechanism of autophagy on ethanol-induced cell damage remain controversial. In this manuscript, we report the results of our study demonstrating that autophagy can protect gastric mucosal epithelial cells against ethanol toxicity in vitro and in vivo. We have shown that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate ethanol-induced oxidative damage in gastric mucosal epithelial cells. This study brings new and important insights into the mechanism of alcoholic gastric mucosal injury and may provide an avenue for future therapeutic strategies. PMID:28056554

Ebselen by modulating oxidative stress improves hypoxia-induced macroglial Müller cell and vascular injury in the retina.

PubMed

Tan, Sih Min; Deliyanti, Devy; Figgett, William A; Talia, Dean M; de Haan, Judy B; Wilkinson-Berka, Jennifer L

2015-07-01

Oxidative stress is an important contributor to glial and vascular cell damage in ischemic retinopathies. We hypothesized that ebselen via its ability to reduce reactive oxygen species (ROS) and augment nuclear factor-like 2 (Nrf2) anti-oxidants would attenuate hypoxia-induced damage to macroglial Müller cells and also lessen retinal vasculopathy. Primary cultures of rat Müller cells were exposed to normoxia (21% O2), hypoxia (0.5% O2) and ebselen (2.5 μM) for up to 72 h. Oxygen-induced retinopathy (OIR) was induced in C57BL/6J mice while control mice were housed in room air. Mice received vehicle (saline, 5% dimethyl sulfoxide) or ebselen (10 mg/kg) each day between postnatal days 6-18. In cultured Müller cells, flow cytometry for dihydroethidium revealed that ebselen reduced the hypoxia-induced increase in ROS levels, whilst increasing the expression of Nrf2-regulated anti-oxidant genes, heme oxygenase 1, glutathione peroxidase-1, NAD(P)H dehydrogenase quinone oxidoreductase 1 and glutamate-cysteine ligase. Moreover, in Müller cells, ebselen reduced the hypoxia-induced increase in protein levels of pro-angiogenic and pro-inflammatory factors including vascular endothelial growth factor, interleukin-6, monocyte chemoattractant-protein 1 and intercellular adhesion molecule-1, and the mRNA levels of glial fibrillary acidic protein (GFAP), a marker of Müller cell injury. Ebselen improved OIR by attenuating capillary vaso-obliteration and neovascularization and a concomitant reduction in Müller cell gliosis and GFAP. We conclude that ebselen protects against hypoxia-induced injury of retinal Müller cells and the microvasculature, which is linked to its ability to reduce oxidative stress, vascular damaging factors and inflammation. Agents such as ebselen may be potential treatments for retinopathies that feature oxidative stress-mediated damage to glia and the microvasculature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Citral, A Monoterpene Protect Against High Glucose Induced Oxidative Injury in HepG2 Cell In Vitro-An Experimental Study.

PubMed

Subramaniyan, Sri Devi; Natarajan, Ashok Kumar

2017-08-01

Diabetes mellitus, a major metabolic disorder associated with hyperglycaemia is one of the leading cause of death in many developed countries. However, use of natural phytochemicals have been proved to have a protective effect against oxidative damage. To investigate the effect of citral, a monoterpene on high glucose induced cytotoxicity and oxidative stress in human hepatocellular liver carcinoma (Hep G2) cell line. Cells were treated with 50 mM concentration of glucose for 24 hours incubation following citral (30 μM) was added to confluent HepG2 cells. Cell viability, Reactive Oxygen Species (ROS) generation, DNA damage, lipid peroxidation, antioxidants and Mitogen Activated Protein Kinases (MAPKs) signaling were assessed in citral and/or high glucose induced HepG2 cells. Cells treated with glucose (50 mM), resulted in increased cytotoxicity, ROS generation, DNA damage, lipid peroxidation and depletion of enzymatic and non enzymatic antioxidants. In contrast, treatment with citral (30 μM) significantly decreased cell cytotoxicity, ROS generation, DNA damage, lipid peroxidation and increased antioxidants enzymes in high glucose induced HepG2 cells. In addition, the present study highlighted that high glucose treated cells showed increased expression of Extracellular Signal Regulated Protein Kinase-1 (ERK-1), c-Jun N-terminal Kinase (JNK) and p38 in HepG2 cells. On the other hand treatment with citral significantly suppressed the expression of ERK-1, JNK and p38 in high glucose induced HepG2 cells. Citral protects against high glucose induced oxidative stress through inhibiting ROS activated MAPK signaling pathway in HepG2 cells.

Menadione reduction by pharmacological doses of ascorbate induces an oxidative stress that kills breast cancer cells.

PubMed

Beck, Raphaël; Verrax, Julien; Dejeans, Nicolas; Taper, Henryk; Calderon, Pedro Buc

2009-01-01

Oxidative stress generated by ascorbate-driven menadione redox cycling kills MCF7 cells by a concerted mechanism including glycolysis inhibition, loss of calcium homeostasis, DNA damage and changes in mitogen activated protein kinases (MAPK) activities. Cell death is mediated by necrosis rather than apoptosis or macroautophagy. Neither 3-methyladenine nor Z-VAD affects cytotoxicity by ascorbate/menadione (Asc/Men). BAPTA-AM, by restoring cellular capacity to reduce MTT, underlines the role of calcium in the necrotic process. Oxidative stress-mediated cell death is shown by the opposite effects of N-acetylcysteine and 3-aminotriazole. Moreover, oxidative stress induces DNA damage (protein poly-ADP-ribosylation and gamma-H2AX phosphorylation) and inhibits glycolysis. Asc/Men deactivates extracellular signal-regulated kinase (ERK) while activating p38, suggesting an additional mechanism to kill MCF7 cells. Since ascorbate is taken up by cancer cells and, due to their antioxidant enzyme deficiency, oxidative stress should affect cancer cells to a greater extent than normal cells. This differential sensitivity may have clinical applications.

Diminution of Oxidative Damage to Human Erythrocytes and Lymphocytes by Creatine: Possible Role of Creatine in Blood.

PubMed

Qasim, Neha; Mahmood, Riaz

2015-01-01

Creatine (Cr) is naturally produced in the body and stored in muscles where it is involved in energy generation. It is widely used, especially by athletes, as a staple supplement for improving physical performance. Recent reports have shown that Cr displays antioxidant activity which could explain its beneficial cellular effects. We have evaluated the ability of Cr to protect human erythrocytes and lymphocytes against oxidative damage. Erythrocytes were challenged with model oxidants, 2, 2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H2O2) in the presence and absence of Cr. Incubation of erythrocytes with oxidant alone increased hemolysis, methemoglobin levels, lipid peroxidation and protein carbonyl content. This was accompanied by decrease in glutathione levels. Antioxidant enzymes and antioxidant power of the cell were compromised while the activity of membrane bound enzyme was lowered. This suggests induction of oxidative stress in erythrocytes by AAPH and H2O2. However, Cr protected the erythrocytes by ameliorating the AAPH and H2O2 induced changes in these parameters. This protective effect was confirmed by electron microscopic analysis which showed that oxidant-induced cell damage was attenuated by Cr. No cellular alterations were induced by Cr alone even at 20 mM, the highest concentration used. Creatinine, a by-product of Cr metabolism, was also shown to exert protective effects, although it was slightly less effective than Cr. Human lymphocytes were similarly treated with H2O2 in absence and presence of different concentrations of Cr. Lymphocytes incubated with oxidant alone had alterations in various biochemical and antioxidant parameters including decrease in cell viability and induction of DNA damage. The presence of Cr attenuated all these H2O2-induced changes in lymphocytes. Thus, Cr can function as a blood antioxidant, protecting cells from oxidative damage, genotoxicity and can potentially increase their lifespan.

Diminution of Oxidative Damage to Human Erythrocytes and Lymphocytes by Creatine: Possible Role of Creatine in Blood

PubMed Central

Qasim, Neha; Mahmood, Riaz

2015-01-01

Creatine (Cr) is naturally produced in the body and stored in muscles where it is involved in energy generation. It is widely used, especially by athletes, as a staple supplement for improving physical performance. Recent reports have shown that Cr displays antioxidant activity which could explain its beneficial cellular effects. We have evaluated the ability of Cr to protect human erythrocytes and lymphocytes against oxidative damage. Erythrocytes were challenged with model oxidants, 2, 2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H2O2) in the presence and absence of Cr. Incubation of erythrocytes with oxidant alone increased hemolysis, methemoglobin levels, lipid peroxidation and protein carbonyl content. This was accompanied by decrease in glutathione levels. Antioxidant enzymes and antioxidant power of the cell were compromised while the activity of membrane bound enzyme was lowered. This suggests induction of oxidative stress in erythrocytes by AAPH and H2O2. However, Cr protected the erythrocytes by ameliorating the AAPH and H2O2 induced changes in these parameters. This protective effect was confirmed by electron microscopic analysis which showed that oxidant-induced cell damage was attenuated by Cr. No cellular alterations were induced by Cr alone even at 20 mM, the highest concentration used. Creatinine, a by-product of Cr metabolism, was also shown to exert protective effects, although it was slightly less effective than Cr. Human lymphocytes were similarly treated with H2O2 in absence and presence of different concentrations of Cr. Lymphocytes incubated with oxidant alone had alterations in various biochemical and antioxidant parameters including decrease in cell viability and induction of DNA damage. The presence of Cr attenuated all these H2O2-induced changes in lymphocytes. Thus, Cr can function as a blood antioxidant, protecting cells from oxidative damage, genotoxicity and can potentially increase their lifespan. PMID:26555819

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

PubMed

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.

The mitochondria-targeted antioxidant MitoQ protects against organ damage in a lipopolysaccharide-peptidoglycan model of sepsis.

PubMed

Lowes, Damon A; Thottakam, Bensita M V; Webster, Nigel R; Murphy, Michael P; Galley, Helen F

2008-12-01

Sepsis is characterised by a systemic dysregulated inflammatory response and oxidative stress, often leading to organ failure and death. Development of organ dysfunction associated with sepsis is now accepted to be due at least in part to oxidative damage to mitochondria. MitoQ is an antioxidant selectively targeted to mitochondria that protects mitochondria from oxidative damage and which has been shown to decrease mitochondrial damage in animal models of oxidative stress. We hypothesised that if oxidative damage to mitochondria does play a significant role in sepsis-induced organ failure, then MitoQ should modulate inflammatory responses, reduce mitochondrial oxidative damage, and thereby ameliorate organ damage. To assess this, we investigated the effects of MitoQ in vitro in an endothelial cell model of sepsis and in vivo in a rat model of sepsis. In vitro MitoQ decreased oxidative stress and protected mitochondria from damage as indicated by a lower rate of reactive oxygen species formation (P=0.01) and by maintenance of the mitochondrial membrane potential (P<0.005). MitoQ also suppressed proinflammatory cytokine release from the cells (P<0.05) while the production of the anti-inflammatory cytokine interleukin-10 was increased by MitoQ (P<0.001). In a lipopolysaccharide-peptidoglycan rat model of the organ dysfunction that occurs during sepsis, MitoQ treatment resulted in lower levels of biochemical markers of acute liver and renal dysfunction (P<0.05), and mitochondrial membrane potential was augmented (P<0.01) in most organs. These findings suggest that the use of mitochondria-targeted antioxidants such as MitoQ may be beneficial in sepsis.

Spermidine rescues proximal tubular cells from oxidative stress and necrosis after ischemic acute kidney injury.

PubMed

Kim, Jinu

2017-10-01

Kidney ischemia and reperfusion injury (IRI) is associated with a high mortality rate, which is attributed to tubular oxidative stress and necrosis; however, an effective approach to limit IRI remains elusive. Spermidine, a naturally occurring polyamine, protects yeast cells against aging through the inhibition of oxidative stress and necrosis. In the present study, spermidine supplementation markedly attenuated increases in plasma creatinine concentration and tubular injury score after IRI. In addition, exogenous spermidine potently inhibited oxidative stress, especially lipid peroxidation after IRI in kidneys and exposure to hydrogen peroxide in kidney proximal tubular cells, suppressing plasma membrane disruption and necrosis. Consistent with spermidine supplementation, upregulation of ornithine decarboxylase (ODC) in human kidney proximal tubular cells significantly diminished lipid peroxidation and necrosis induced by hydrogen peroxide-induced injury. Conversely, ODC deficiency significantly enhanced lipid peroxidation and necrosis after exposure to hydrogen peroxide. Finally, small interfering RNA-mediated ODC inhibition induced functional and histological damage in kidneys as well as it increased lipid hydroperoxide levels after IRI. In conclusion, these data suggest that spermidine level determines kidney proximal tubular damage through oxidative stress and necrosis induced by IRI, and this finding provides a novel target for prevention of tubular damage induced by IRI.

Cell cycle stage-specific roles of Rad18 in tolerance and repair of oxidative DNA damage

PubMed Central

Yang, Yang; Durando, Michael; Smith-Roe, Stephanie L.; Sproul, Chris; Greenwalt, Alicia M.; Kaufmann, William; Oh, Sehyun; Hendrickson, Eric A.; Vaziri, Cyrus

2013-01-01

The E3 ubiquitin ligase Rad18 mediates tolerance of replication fork-stalling bulky DNA lesions, but whether Rad18 mediates tolerance of bulky DNA lesions acquired outside S-phase is unclear. Using synchronized cultures of primary human cells, we defined cell cycle stage-specific contributions of Rad18 to genome maintenance in response to ultraviolet C (UVC) and H2O2-induced DNA damage. UVC and H2O2 treatments both induced Rad18-mediated proliferating cell nuclear antigen mono-ubiquitination during G0, G1 and S-phase. Rad18 was important for repressing H2O2-induced (but not ultraviolet-induced) double strand break (DSB) accumulation and ATM S1981 phosphorylation only during G1, indicating a specific role for Rad18 in processing of oxidative DNA lesions outside S-phase. However, H2O2-induced DSB formation in Rad18-depleted G1 cells was not associated with increased genotoxin sensitivity, indicating that back-up DSB repair mechanisms compensate for Rad18 deficiency. Indeed, in DNA LigIV-deficient cells Rad18-depletion conferred H2O2-sensitivity, demonstrating functional redundancy between Rad18 and non-homologous end joining for tolerance of oxidative DNA damage acquired during G1. In contrast with G1-synchronized cultures, S-phase cells were H2O2-sensitive following Rad18-depletion. We conclude that although Rad18 pathway activation by oxidative lesions is not restricted to S-phase, Rad18-mediated trans-lesion synthesis by Polη is dispensable for damage-tolerance in G1 (because of back-up non-homologous end joining-mediated DSB repair), yet Rad18 is necessary for damage tolerance during S-phase. PMID:23295675

Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

ERIC Educational Resources Information Center

Yip, Cheng-Wai

2007-01-01

Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

Studies of protein oxidation as a product quality attribute on a scale-down model for cell culture process development.

PubMed

Lee, Nacole D; Kondragunta, Bhargavi; Uplekar, Shaunak; Vallejos, Jose; Moreira, Antonio; Rao, Govind

2015-01-01

Of importance to the biological properties of proteins produced in cell culture systems are the complex post-translational modifications that are affected by variations in process conditions. Protein oxidation, oxidative modification to intracellular proteins that involves cleavage of the polypeptide chain, and modifications of the amino acid side chains can be affected by such process variations. Dissolved oxygen is a parameter of increasing interest since studies have shown that despite the necessity of oxygen for respiration, there may also be some detrimental effects of oxygen to the cell. Production and accumulation of reactive oxygen species can cause damage to proteins as a result of oxidation of the cell and cellular components. Variation, or changes to cell culture products, can affect function, clearance rate, immunogenicity, and specific activity, which translates into clinical implications. The effect of increasing dissolved oxygen on protein oxidation in immunoglobulin G3-producing mouse hybridoma cells was studied using 50 mL high-throughput mini-bioreactors that employ non-invasive optical sensor technology for monitoring and closed feedback control of pH and dissolved oxygen. Relative protein carbonyl concentration of proteins produced under varying levels of dissolved oxygen was measured by enzyme-linked immunosorbent assay and used as an indicator of oxidative damage. A trend of increasing protein carbonyl content in response to increasing dissolved oxygen levels under controlled conditions was observed. Protein oxidation, oxidative modification to intracellular proteins that involves cleavage of the polypeptide chain, and modifications of the amino acid side chains can be affected by variations in dissolved oxygen levels in cell culture systems. Studies have shown that despite the necessity of oxygen for respiration, there may be detrimental effects of oxygen to the cell. Production and accumulation of reactive oxygen species can cause damage to proteins as a result of oxidation of the cell and cellular components, affecting function, clearance rate, immunogenicity, and specific activity, which translates into clinical implications. The effect of increasing dissolved oxygen on protein oxidation in immunoglobulin G3-producing mouse hybridoma cells was studied using 50 mL high-throughput mini-bioreactors that employ non-invasive optical sensor technology for monitoring and closed feedback control of pH and dissolved oxygen. Protein carbonyl concentration of proteins produced under varying levels of dissolved oxygen was measured by enzyme-linked immunosorbent assay and used as an indicator of oxidative damage. A trend of increasing protein carbonyl content in response to increasing dissolved oxygen levels under controlled conditions was observed. © PDA, Inc. 2015.

Oxidative stress damages rRNA inside the ribosome and differentially affects the catalytic center

PubMed Central

Willi, Jessica; Küpfer, Pascal; Evéquoz, Damien; Fernandez, Guillermo; Polacek, Norbert

2018-01-01

Abstract Intracellular levels of reactive oxygen species (ROS) increase as a consequence of oxidative stress and represent a major source of damage to biomolecules. Due to its high cellular abundance RNA is more frequently the target for oxidative damage than DNA. Nevertheless the functional consequences of damage on stable RNA are poorly understood. Using a genome-wide approach, based on 8-oxo-guanosine immunoprecipitation, we present evidence that the most abundant non-coding RNA in a cell, the ribosomal RNA (rRNA), is target for oxidative nucleobase damage by ROS. Subjecting ribosomes to oxidative stress, we demonstrate that oxidized 23S rRNA inhibits the ribosome during protein biosynthesis. Placing single oxidized nucleobases at specific position within the ribosome's catalytic center by atomic mutagenesis resulted in markedly different functional outcomes. While some active site nucleobases tolerated oxidative damage well, oxidation at others had detrimental effects on protein synthesis by inhibiting different sub-steps of the ribosomal elongation cycle. Our data provide molecular insight into the biological consequences of RNA oxidation in one of the most central cellular enzymes and reveal mechanistic insight on the role of individual active site nucleobases during translation. PMID:29309687

The Role of Thyroid Hormones as Inductors of Oxidative Stress and Neurodegeneration

PubMed Central

Villanueva, I.; Alva-Sánchez, C.; Pacheco-Rosado, J.

2013-01-01

Reactive oxygen species (ROS) are oxidizing agents amply implicated in tissue damage. ROS production is inevitably linked to ATP synthesis in most cells, and the rate of production is related to the rate of cell respiration. Multiple antioxidant mechanisms limit ROS dispersion and interaction with cell components, but, when the balance between ROS production and scavenging is lost, oxidative damage develops. Many traits of aging are related to oxidative damage by ROS, including neurodegenerative diseases. Thyroid hormones (THs) are a major factor controlling metabolic and respiratory rates in virtually all cell types in mammals. The general metabolic effect of THs is a relative acceleration of the basal metabolism that includes an increase of the rate of both catabolic and anabolic reactions. THs are related to oxidative stress not only by their stimulation of metabolism but also by their effects on antioxidant mechanisms. Thyroid dysfunction increases with age, so changes in THs levels in the elderly could be a factor affecting the development of neurodegenerative diseases. However, the relationship is not always clear. In this review, we analyze the participation of thyroid hormones on ROS production and oxidative stress, and the way the changes in thyroid status in aging are involved in neurodegenerative diseases. PMID:24386502

Cancer cells recovering from damage exhibit mitochondrial restructuring and increased aerobic glycolysis.

PubMed

Akakura, Shin; Ostrakhovitch, Elena; Sanokawa-Akakura, Reiko; Tabibzadeh, Siamak

2014-06-13

Instead of relying on mitochondrial oxidative phosphorylation, most cancer cells rely heavily on aerobic glycolysis, a phenomenon termed as "the Warburg effect". We considered that this effect is a direct consequence of damage which persists in cancer cells that recover from damage. To this end, we studied glycolysis and rate of cell proliferation in cancer cells that recovered from severe damage. We show that in vitro Damage-Recovered (DR) cells exhibit mitochondrial structural remodeling, display Warburg effect, and show increased in vitro and in vivo proliferation and tolerance to damage. To test whether cancer cells derived from tumor microenvironment can show similar properties, we isolated Damage-Recovered (T(DR)) cells from tumors. We demonstrate that T(DR) cells also show increased aerobic glycolysis and a high proliferation rate. These findings show that Warburg effect and its consequences are induced in cancer cells that survive severe damage. Copyright © 2014 Elsevier Inc. All rights reserved.

Pharmacological activities of an eye drop containing Matricaria chamomilla and Euphrasia officinalis extracts in UVB-induced oxidative stress and inflammation of human corneal cells.

PubMed

Bigagli, Elisabetta; Cinci, Lorenzo; D'Ambrosio, Mario; Luceri, Cristina

2017-08-01

Ultraviolet B (UVB) exposure is a risk factor for corneal damage resulting in oxidative stress, inflammation and cell death. The aim of this study was to investigate the potential protective effects of a commercial eye drop (Dacriovis™) containing Matricaria chamomilla and Euphrasia officinalis extracts on human corneal epithelial cells (HCEC-12) against UVB radiation-induced oxidative stress and inflammation as well as the underlying mechanisms. The antioxidant potential of the eye drops was evaluated by measuring the ferric reducing antioxidant power and the total phenolic content by Folin-Ciocalteu reagent. HCEC-12 cells were exposed to UVB radiation and treated with the eye drops at various concentrations. Cell viability, wound healing assay, reactive oxygen species (ROS) levels, protein and lipid oxidative damage and COX-2, IL-1β, iNOS, SOD-2, HO-1 and GSS gene expression, were assessed. Eye drops were able to protect corneal epithelial cells from UVB-induced cell death and ameliorated the wound healing; the eye drops exhibited a strong antioxidant activity, decreasing ROS levels and protein and lipid oxidative damage. Eye drops also exerted anti-inflammatory activities by decreasing COX-2, IL-1β, iNOS expression, counteracted UVB-induced GSS and SOD-2 expression and restored HO-1 expression to control levels. These findings suggest that an eye drop containing Matricaria chamomilla and Euphrasia officinalis extracts exerts positive effects against UVB induced oxidative stress and inflammation and may be useful in protecting corneal epithelial cells from UVB exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

A single portion of blueberry (Vaccinium corymbosum L) improves protection against DNA damage but not vascular function in healthy male volunteers.

PubMed

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.

Evaluation of Both Free Radical Scavenging Capacity and Antioxidative Damage Effect of Polydatin.

PubMed

Jin, Ju; Li, Yan; Zhang, Xiuli; Chen, Tongsheng; Wang, Yifei; Wang, Zhiping

Cellular damage such as oxidation and lipid peroxidation, and DNA damage induced by free-radicals like reactive oxygen species, has been implicated in several diseases. Radicals generated by 2,2-azobis (2-amidino-propane) dihydrochloride (AAPH) are similar to physiologically active ones. In this study we found that polydatin, a resveratrol natural precursor derived from many sources, has the capacity of free radical scavenging and antioxidative damage. Using free radical scavenging assays, the IC50 values of polydatin were 19.25 and 5.29 μg/ml with the DPPH and the ABTS assay, respectively, and 0.125 mg ferrous sulfate/1 mg polydatin with the FRAP assay. With the AAPH-induced oxidative injury cell model assay, polydatin showed a strong protective effect against the human liver tumor HepG2 cell oxidative stress damage. These results indicate that the antioxidant properties of polydatin have great potential for use as an alternative to more toxic synthetic antioxidants as an additive in food, cosmetics and pharmaceutical preparations for the treatment of oxidative diseases.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Juanjuan; Zhang, Yu; Xu, Wentao, E-mail: xuwentaoboy@sina.com

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 notmore » 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 OTA in vitro.« less

Magmas functions as a ROS regulator and provides cytoprotection against oxidative stress-mediated damages

PubMed Central

Srivastava, S; Sinha, D; Saha, P P; Marthala, H; D'Silva, P

2014-01-01

Redox imbalance generates multiple cellular damages leading to oxidative stress-mediated pathological conditions such as neurodegenerative diseases and cancer progression. Therefore, maintenance of reactive oxygen species (ROS) homeostasis is most important that involves well-defined antioxidant machinery. In the present study, we have identified for the first time a component of mammalian protein translocation machinery Magmas to perform a critical ROS regulatory function. Magmas overexpression has been reported in highly metabolically active tissues and cancer cells that are prone to oxidative damage. We found that Magmas regulates cellular ROS levels by controlling its production as well as scavenging. Magmas promotes cellular tolerance toward oxidative stress by enhancing antioxidant enzyme activity, thus preventing induction of apoptosis and damage to cellular components. Magmas enhances the activity of electron transport chain (ETC) complexes, causing reduced ROS production. Our results suggest that J-like domain of Magmas is essential for maintenance of redox balance. The function of Magmas as a ROS sensor was found to be independent of its role in protein import. The unique ROS modulatory role of Magmas is highlighted by its ability to increase cell tolerance to oxidative stress even in yeast model organism. The cytoprotective capability of Magmas against oxidative damage makes it an important candidate for future investigation in therapeutics of oxidative stress-related diseases. PMID:25165880

In vivo reduction of erythrocyte oxidant stress in a murine model of beta-thalassemia.

PubMed

de Franceschi, Lucia; Turrini, Franco; Honczarenko, Marek; Ayi, Kojio; Rivera, Alicia; Fleming, Mark D; Law, Terry; Mannu, Franca; Kuypers, Frans A; Bast, Aalt; van der Vijgh, Wim J F; Brugnara, Carlo

2004-11-01

Oxidant damage is an important contributor to the premature destruction of erythrocytes and anemia in thalassemias. To assess the extent of oxidant damage of circulating erythrocytes and the effects of antioxidant therapy on erythrocyte characteristics and anemia, we used a mouse model of human beta-thalassemia intermedia (b1/b2 deletion). Several parameters indicative of oxidant damage were measured at baseline and following administration of the semi-synthetic flavonoid antioxidant, 7-monohydroxyethylrutoside (monoHER), to beta-thalassemic mice at a dose of either 500 mg/kg i.p. once a day (n=6) or 250 mg/kg i.p. twice a day (n=6) for 21 days. Significant erythrocyte oxidant damage at baseline was indicated by: (i) dehydration, reduced cell K content, and up-regulated K-Cl co-transport; (ii) marked membrane externalization of phosphatidylserine; (iii) reduced plasma and membrane content of vitamin E; and (iv) increased membrane bound IgG. MonoHER treatment increased erythrocyte K content, and markedly improved all cellular indicators of oxidant stress and of lipid membrane peroxidation. While anemia did not improve, monoHER therapy reduced reticulocyte counts, improved survival of a fraction of red cells, and reduced ineffective erythropoiesis with decreased total bilirubin, lactate dehydrogenase and plasma iron. Antioxidant therapy reverses several indicators of oxidant damage in vivo. These promising antioxidant effects of monoHER should be investigated further.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Yang; Kojima, Chikara; Chignell, Colin

2011-09-15

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{supmore » 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.« less

Evaluation of Cassia tora Linn. against Oxidative Stress-induced DNA and Cell Membrane Damage

PubMed Central

Kumar, R Sunil; Narasingappa, Ramesh Balenahalli; Joshi, Chandrashekar G; Girish, Talakatta K; Prasada Rao, Ummiti JS; Danagoudar, Ananda

2017-01-01

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. PMID:28584491

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

PubMed

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.

Oxidative Stress and Nucleic Acid Oxidation in Patients with Chronic Kidney Disease

PubMed Central

Sung, Chih-Chien; Hsu, Yu-Chuan; Lin, Yuh-Feng

2013-01-01

Patients with chronic kidney disease (CKD) have high cardiovascular mortality and morbidity and a high risk for developing malignancy. Excessive oxidative stress is thought to play a major role in elevating these risks by increasing oxidative nucleic acid damage. Oxidative stress results from an imbalance between reactive oxygen/nitrogen species (RONS) production and antioxidant defense mechanisms and can cause vascular and tissue injuries as well as nucleic acid damage in CKD patients. The increased production of RONS, impaired nonenzymatic or enzymatic antioxidant defense mechanisms, and other risk factors including gene polymorphisms, uremic toxins (indoxyl sulfate), deficiency of arylesterase/paraoxonase, hyperhomocysteinemia, dialysis-associated membrane bioincompatibility, and endotoxin in patients with CKD can inhibit normal cell function by damaging cell lipids, arachidonic acid derivatives, carbohydrates, proteins, amino acids, and nucleic acids. Several clinical biomarkers and techniques have been used to detect the antioxidant status and oxidative stress/oxidative nucleic acid damage associated with long-term complications such as inflammation, atherosclerosis, amyloidosis, and malignancy in CKD patients. Antioxidant therapies have been studied to reduce the oxidative stress and nucleic acid oxidation in patients with CKD, including alpha-tocopherol, N-acetylcysteine, ascorbic acid, glutathione, folic acid, bardoxolone methyl, angiotensin-converting enzyme inhibitor, and providing better dialysis strategies. This paper provides an overview of radical production, antioxidant defence, pathogenesis and biomarkers of oxidative stress in patients with CKD, and possible antioxidant therapies. PMID:24058721

Evaluation of imazethapyr-induced DNA oxidative damage by alkaline Endo III- and Fpg-modified single-cell gel electrophoresis assay in Hypsiboas pulchellus tadpoles (Anura, Hylidae).

PubMed

Pérez-Iglesias, Juan Manuel; Ruiz de Arcaute, Celeste; Natale, Guillermo S; Soloneski, S; Larramendy, Marcelo L

2017-08-01

Imazethapyr (IMZT) is a selective postemergent herbicide with residual action. Available data analyzing its effects in aquatic vertebrates are scarce. In previous studies, we demonstrated that IMZT induces lesions into the DNA of Hypsiboas pulchellus tadpoles using the single-cell gel electrophoresis (SCGE) assay as a biomarker for genotoxicity. Currently, this assay can be modified by including incubation with lesion-specific endonucleases, e.g., endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg), which detect oxidized pyrimidine and purine bases, respectively. The aim of this study was to evaluate the role of oxidative stress in the genotoxic damage in circulating blood cells of H. pulchellus tadpoles exposed to the IMZT-based Pivot H ® formulation (10.59% IMZT) at a concentration equivalent to 25% of the LC 50 (96h) value (0.39mg/L IMZT) during 48 and 96h. Our results demonstrate that the herbicide induces oxidative DNA damage on H. pulchellus tadpoles at purines bases but not at pyrimidines. Our findings represent the first evidence of oxidative damage caused by IMZT on anuran DNA using the alkaline restriction enzyme-modified SCGE assay. Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of iron and vitamin C-containing supplements on preterm human milk: in vitro.

PubMed

Friel, James K; Diehl-Jones, William L; Suh, Miyoung; Tsopmo, Apollinaire; Shirwadkar, Vaibhav P

2007-05-15

Stress due to reactive oxygen species (ROS) may lead to neonatal diseases, such as necrotizing enterocolitis and respiratory distress. Enteral supplements for premature infants (PREM) added to human milk (HM) to increase nutrient content may induce lipid oxidation due to free radical formation via Fenton chemistry. We hypothesized that ferrous iron and vitamin C-containing supplements added to HM in vitro cause oxidation of milk fats, affect intracellular redox balance, and induce DNA damage. Lipid peroxidation in HM was measured by FOX-2 and TBARS assays; fatty acid composition of supplemented HM was measured by gas chromatography. Two cell culture bioassays were used for assessing either intracellular oxidative stress or DNA damage: the former involved Caco-2BBe cells, a secondary differentiated cell line, and the latter utilized FHS-74 Int cells, a primary fetal small intestinal culture. Lipid oxidation products of HM increased after the addition of iron alone, iron and vitamin C, or iron and a vitamin C-containing supplement (Trivisol, TVS). A reduced content of mono and polyunsaturated fatty acids in HM was also observed. Iron, not iron+vitamin C, but iron+TVS induced significant intracellular oxidative stress in FHS-74 Int cells. In contrast, iron, either alone or in combination with TVS or vitamin C, increased DNA damage in Caco-2BBE cells. Iron supplementation may increase oxidative stress in PREM infants and should be given separately from vitamin C-containing supplements.

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

PubMed

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.

Over-expression of heme oxygenase-1 promotes oxidative mitochondrial damage in rat astroglia.

PubMed

Song, Wei; Su, Haixiang; Song, Sisi; Paudel, Hemant K; Schipper, Hyman M

2006-03-01

Glial heme oxygenase-1 is over-expressed in the CNS of subjects with Alzheimer disease (AD), Parkinson disease (PD) and multiple sclerosis (MS). Up-regulation of HO-1 in rat astroglia has been shown to facilitate iron sequestration by the mitochondrial compartment. To determine whether HO-1 induction promotes mitochondrial oxidative stress, assays for 8-epiPGF(2alpha) (ELISA), protein carbonyls (ELISA) and 8-OHdG (HPLC-EC) were used to quantify oxidative damage to lipids, proteins, and nucleic acids, respectively, in mitochondrial fractions and whole-cell compartments derived from cultured rat astroglia engineered to over-express human (h) HO-1 by transient transfection. Cell viability was assessed by trypan blue exclusion and the MTT assay, and cell proliferation was determined by [3H] thymidine incorporation and total cell counts. In rat astrocytes, hHO-1 over-expression (x 3 days) resulted in significant oxidative damage to mitochondrial lipids, proteins, and nucleic acids, partial growth arrest, and increased cell death. These effects were attenuated by incubation with 1 microM tin mesoporphyrin, a competitive HO inhibitor, or the iron chelator, deferoxamine. Up-regulation of HO-1 engenders oxidative mitochondrial injury in cultured rat astroglia. Heme-derived ferrous iron and carbon monoxide (CO) may mediate the oxidative modification of mitochondrial lipids, proteins and nucleic acids in these cells. Glial HO-1 hyperactivity may contribute to cellular oxidative stress, pathological iron deposition, and bioenergetic failure characteristic of degenerating and inflamed neural tissues and may constitute a rational target for therapeutic intervention in these conditions. Copyright 2005 Wiley-Liss, Inc.

ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function

PubMed Central

Pi, Jingbo; Zhang, Qiang; Fu, Jingqi; Woods, Courtney G.; Hou, Yongyong; Corkey, Barbara E; Collins, Sheila; Andersen, Melvin E.

2009-01-01

This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H2O2, act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function. PMID:19501608

Repair of oxidative DNA damage, cell-cycle regulation and neuronal death may influence the clinical manifestation of Alzheimer's disease.

PubMed

Silva, Aderbal R T; Santos, Ana Cecília Feio; Farfel, Jose M; Grinberg, Lea T; Ferretti, Renata E L; Campos, Antonio Hugo Jose Froes Marques; Cunha, Isabela Werneck; Begnami, Maria Dirlei; Rocha, Rafael M; Carraro, Dirce M; de Bragança Pereira, Carlos Alberto; Jacob-Filho, Wilson; Brentani, Helena

2014-01-01

Alzheimer's disease (AD) is characterized by progressive cognitive decline associated with a featured neuropathology (neuritic plaques and neurofibrillary tangles). Several studies have implicated oxidative damage to DNA, DNA repair, and altered cell-cycle regulation in addition to cell death in AD post-mitotic neurons. However, there is a lack of studies that systematically assess those biological processes in patients with AD neuropathology but with no evidence of cognitive impairment. We evaluated markers of oxidative DNA damage (8-OHdG, H2AX), DNA repair (p53, BRCA1, PTEN), and cell-cycle (Cdk1, Cdk4, Cdk5, Cyclin B1, Cyclin D1, p27Kip1, phospho-Rb and E2F1) through immunohistochemistry and cell death through TUNEL in autopsy hippocampal tissue samples arrayed in a tissue microarray (TMA) composed of three groups: I) "clinical-pathological AD" (CP-AD)--subjects with neuropathological AD (Braak ≥ IV and CERAD = B or C) and clinical dementia (CDR ≥ 2, IQCODE>3.8); II) "pathological AD" (P-AD)--subjects with neuropathological AD (Braak ≥ IV and CERAD = B or C) and without cognitive impairment (CDR 0, IQCODE<3.2); and III) "normal aging" (N)--subjects without neuropathological AD (Braak ≤ II and CERAD 0 or A) and with normal cognitive function (CDR 0, IQCODE<3.2). Our results show that high levels of oxidative DNA damage are present in all groups. However, significant reductions in DNA repair and cell-cycle inhibition markers and increases in cell-cycle progression and cell death markers in subjects with CP-AD were detected when compared to both P-AD and N groups, whereas there were no significant differences in the studied markers between P-AD individuals and N subjects. This study indicates that, even in the setting of pathological AD, healthy cognition may be associated with a preserved repair to DNA damage, cell-cycle regulation, and cell death in post-mitotic neurons.

Chromium (VI)-induced oxidative stress, apoptotic cell death and modulation of p53 tumor suppressor gene.

PubMed

Bagchi, D; Bagchi, M; Stohs, S J

2001-06-01

Chromium (VI) is a widely used industrial chemical, extensively used in paints, metal finishes, steel including stainless steel manufacturing, alloy cast irons, chrome, and wood treatment. On the contrary, chromium (III) salts such as chromium polynicotinate, chromium chloride and chromium picolinate, are used as micronutrients and nutritional supplements, and have been demonstrated to exhibit a significant number of health benefits in rodents and humans. However, the cause for the hexavalent chromium to induce cytotoxicity is not entirely understood. A series of in vitro and in vivo studies have demonstrated that chromium (VI) induces an oxidative stress through enhanced production of reactive oxygen species (ROS) leading to genomic DNA damage and oxidative deterioration of lipids and proteins. A cascade of cellular events occur following chromium (VI)-induced oxidative stress including enhanced production of superoxide anion and hydroxyl radicals, increased lipid peroxidation and genomic DNA fragmentation, modulation of intracellular oxidized states, activation of protein kinase C, apoptotic cell death and altered gene expression. In this paper, we have demonstrated concentration- and time-dependent effects of sodium dichromate (chromium (VI) or Cr (VI)) on enhanced production of superoxide anion and hydroxyl radicals, changes in intracellular oxidized states as determined by laser scanning confocal microscopy, DNA fragmentation and apoptotic cell death (by flow cytometry) in human peripheral blood mononuclear cells. These results were compared with the concentration-dependent effects of chromium (VI) on chronic myelogenous leukemic K562 cells and J774A.1 murine macrophage cells. Chromium (VI)-induced enhanced production of ROS, as well as oxidative tissue and DNA damage were observed in these cells. More pronounced effect was observed on chronic myelogenous leukemic K562 cells and J774A.1 murine macrophage cells. Furthermore, we have assessed the effect of a single oral LD50 dose of chromium (VI) on female C57BL/6Ntac and p53-deficient C57BL/6TSG p53 mice on enhanced production of superoxide anion, lipid peroxidation and DNA fragmentation in the hepatic and brain tissues. Chromium (VI)-induced more pronounced oxidative damage in p53 deficient mice. This in vivo study highlighted that apoptotic regulatory protein p53 may play a major role in chromium (VI)-induced oxidative stress and toxicity. Taken together, oxidative stress and oxidative tissue damage, and a cascade of cellular events including modulation of apoptotic regulatory gene p53 are involved in chromium (VI)-induced toxicity and carcinogenesis.

Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

NASA Astrophysics Data System (ADS)

Caputo, Fanny; de Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

2015-09-01

Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

CONCENTRATED AMBIENT AIR POLLUTION CREATES OXIDATIVE STRESS IN CNS MICROGLIA.

EPA Science Inventory

Nanometer size particles carry free radical activity on their surface and can produce oxidative stress (OS)-mediated damage upon impact to target cells. The initiating event of phage cell activation (i.e., the oxidative burst) is unknown, although many proximal events have been i...

The RNA surveillance protein SMG1 activates p53 in response to DNA double-strand breaks but not exogenously oxidized mRNA

PubMed Central

Gewandter, Jennifer S; Bambara, Robert A

2011-01-01

DNA damage, stalled replication forks, errors in mRNA splicing and availability of nutrients activate specific phosphatidylinositiol-3-kinase-like kinases (PIKKs) that in turn phosphorylate downstream targets such as p53 on serine 15. While the PIKK proteins ATM and ATR respond to specific DNA lesions, SMG1 responds to errors in mRNA splicing and when cells are exposed to genotoxic stress. Yet, whether genotoxic stress activates SMG1 through specific types of DNA lesions or RNA damage remains poorly understood. Here, we demonstrate that siRNA oligonucleotides targeting the mRNA surveillance proteins SMG1, Upf1, Upf2 or the PIKK protein ATM attenuated p53 (ser15) phosphorylation in cells damaged by high oxygen (hyperoxia), a model of persistent oxidative stress that damages nucleotides. In contrast, loss of SMG1 or ATM, but not Upf1 or Upf2 reduced p53 (ser15) phosphorylation in response to DNA double strand breaks produced by expression of the endonuclease I-PpoI. To determine whether SMG1-dependent activation of p53 was in response to oxidative mRNA damage, mRNA encoding green fluorescence protein (GFP) transcribed in vitro was oxidized by Fenton chemistry and transfected into cells. Although oxidation of GFP mRNA resulted in dose-dependent fragmentation of the mRNA and reduced expression of GFP, it did not stimulate p53 or the p53-target gene p21. These findings establish SMG1 activates p53 in response to DNA double strand breaks independent of the RNA surveillance proteins Upf1 or Upf2; however, these proteins can stimulate p53 in response to oxidative stress but not necessarily oxidized RNA. PMID:21701263

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Hui; Shi, Qiong; Song, Xiufang

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 observedmore » 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.« less

Concentration effects of grape seed extracts in anti-oral cancer cells involving differential apoptosis, oxidative stress, and DNA damage.

PubMed

Yen, Ching-Yu; Hou, Ming-Feng; Yang, Zhi-Wen; Tang, Jen-Yang; Li, Kun-Tzu; Huang, Hurng-Wern; Huang, Yu-Hsuan; Lee, Sheng-Yang; Fu, Tzu-Fun; Hsieh, Che-Yu; Chen, Bing-Hung; Chang, Hsueh-Wei

2015-03-29

Grape seeds extract (GSE) is a famous health food supplement for its antioxidant property. Different concentrations of GSE may have different impacts on cellular oxidative/reduction homeostasis. Antiproliferative effect of GSE has been reported in many cancers but rarely in oral cancer. The aim of this study is to examine the antioral cancer effects of different concentrations of GSE in terms of cell viability, apoptosis, reactive oxygen species (ROS), mitochondrial function, and DNA damage. High concentrations (50-400 μg/ml) of GSE dose-responsively inhibited proliferation of oral cancer Ca9-22 cells but low concentrations (1-10 μg/ml) of GSE showed a mild effect in a MTS assay. For apoptosis analyses, subG1 population and annexin V intensity in high concentrations of GSE-treated Ca9-22 cells was increased but less so at low concentrations. ROS generation and mitochondrial depolarization increased dose-responsively at high concentrations but showed minor changes at low concentrations of GSE in Ca9-22 cells. Additionally, high concentrations of GSE dose-responsively induced more γH2AX-based DNA damage than low concentrations. Differential concentrations of GSE may have a differentially antiproliferative function against oral cancer cells via differential apoptosis, oxidative stress and DNA damage.

Oxidative stress-induced protein damage inhibits DNA repair and determines mutation risk and anticancer drug effectiveness

PubMed Central

McAdam, Elizabeth; Brem, Reto; Karran, Peter

2016-01-01

The relationship between sun exposure and non-melanoma skin cancer risk is well established. Solar ultraviolet radiation (UV; wavelengths 280-400 nm) is firmly implicated in skin cancer development. Nucleotide excision repair (NER) protects against cancer by removing potentially mutagenic DNA lesions induced by UVB (280-320 nm). How the 20-fold more abundant UVA (320-400 mn) component of solar UV radiation increases skin cancer risk is not understood. We demonstrate here that the contribution of UVA to the effects of UV radiation on cultured human cells is largely independent of its ability to damage DNA. Instead, the effects of UVA reflect the induction of oxidative stress that causes extensive protein oxidation. Because NER proteins are among those damaged, UVA irradiation inhibits NER and increases the cells’ susceptibility to mutation by UVB. NER inhibition is a common consequence of oxidative stress. Exposure to chemical oxidants, treatment with drugs that deplete cellular antioxidants, and interventions that interfere with glucose metabolism to disrupt the supply of cellular reducing power all inhibit NER. Tumor cells are often in a condition of oxidative stress and one effect of the NER inhibition that results from stress-induced protein oxidation is an increased sensitivity to the anticancer drug cisplatin. Statement of implication: Since NER is both a defence against cancer a significant determinant of cell survival after treatment with anticancer drugs, its attenuation by protein damage under conditions of oxidative-stress has implications for both cancer risk and for the effectiveness of anticancer therapy. PMID:27106867

Pro-oxidant Induced DNA Damage in Human Lymphoblastoid Cells: Homeostatic Mechanisms of Genotoxic Tolerance

PubMed Central

Seager, Anna L.

2012-01-01

Oxidative stress contributes to many disease etiologies including ageing, neurodegeneration, and cancer, partly through DNA damage induction (genotoxicity). Understanding the i nteractions of free radicals with DNA is fundamental to discern mutation risks. In genetic toxicology, regulatory authorities consider that most genotoxins exhibit a linear relationship between dose and mutagenic response. Yet, homeostatic mechanisms, including DNA repair, that allow cells to tolerate low levels of genotoxic exposure exist. Acceptance of thresholds for genotoxicity has widespread consequences in terms of understanding cancer risk and regulating human exposure to chemicals/drugs. Three pro-oxidant chemicals, hydrogen peroxide (H2O2), potassium bromate (KBrO3), and menadione, were examined for low dose-response curves in human lymphoblastoid cells. DNA repair and antioxidant capacity were assessed as possible threshold mechanisms. H2O2 and KBrO3, but not menadione, exhibited thresholded responses, containing a range of nongenotoxic low doses. Levels of the DNA glycosylase 8-oxoguanine glycosylase were unchanged in response to pro- oxidant stress. DNA repair–focused gene expression arrays reported changes in ATM and BRCA1, involved in double-strand break repair, in response to low-dose pro-oxidant exposure; however, these alterations were not substantiated at the protein level. Determination of oxidatively induced DNA damage in H2O2-treated AHH-1 cells reported accumulation of thymine glycol above the genotoxic threshold. Further, the H2O2 dose-response curve was shifted by modulating the antioxidant glutathione. Hence, observed pro- oxidant thresholds were due to protective capacities of base excision repair enzymes and antioxidants against DNA damage, highlighting the importance of homeostatic mechanisms in “genotoxic tolerance.” PMID:22539617

Evaluation of free radical scavenging capacity and antioxidative damage effect of resveratrol-nanostructured lipid carriers

NASA Astrophysics Data System (ADS)

Jin, Ju; Shi, Fan; Li, Qiu-wen; Li, Pei-shan; Chen, Tong-sheng; Wang, Yi-fei; Wang, Zhi-ping

2016-03-01

Cellular damage induced by free-radicals like reactive oxygen species has been implicated in several diseases. 2, 2-azobis(2-amidino-propane) dihydrochloride(AAPH) generates two potent ROS capable of inducing lipid peroxidation: alkoxy radical(RO-) and peroxy radical(ROO-). These radicals are similar to those that are physiologically active and thus might initiate a cascade of intracellular toxic events leading to oxidation, lipid peroxidation, DNA damage and subsequent cell death. Hence naturally anti-oxidant play a vital role in combating these conditions. In this study, resveratrol loaded nanostructured lipid carriers (Res-NLC) was prepared by hot melting and then high pressure homogenization technique. The effects of Res-NLC on free radical scavenging capacity and antioxidative damage is investigated. The particle size and zeta potential of Res-NLC were 139.3 ± 1.7 nm and -11.21 ± 0.41 mV, respectively. By free radical scavenging assays, the IC50 value of Res-NLC were 19.25, 5.29 μg/mL with DPPH, ABTS assay respectively, and 0.161 mg ferrous sulfate/1 mg Res-NLC with FRAP assay; and by AAPH-induced oxidative injury cell model assay, Res-NLC showed the strong protective effect against the human liver tumor HepG2 cell oxidative stress damage. These results indicated that the antioxidant properties of Res-NLC hold great potential used as an alternative to more toxic synthetic antioxidants as an additive in food, cosmetic and pharmaceutical preparations for the oxidative diseases treatment.

On the possible origins of DNA damage in human spermatozoa.

PubMed

Aitken, R J; De Iuliis, G N

2010-01-01

DNA damage in the male germ line has been linked with a variety of adverse clinical outcomes including impaired fertility, an increased incidence of miscarriage and an enhanced risk of disease in the offspring. The origins of this DNA damage could, in principle, involve: (i) abortive apoptosis initiated post meiotically when the ability to drive this process to completion is in decline (ii) unresolved strand breaks created during spermiogenesis to relieve the torsional stresses associated with chromatin remodelling and (iii) oxidative stress. In this article, we present a two-step hypothesis for the origins of DNA damage in human spermatozoa that highlights the significance of oxidative stress acting on vulnerable, poorly protaminated cells generated as a result of defective spermiogenesis. We further propose that these defective cells are characterized by several hallmarks of 'dysmaturity' including the retention of excess residual cytoplasm, persistent nuclear histones, poor zona binding and disrupted chaperone content. The oxidative stress experienced by these cells may originate from infiltrating leukocytes or, possibly, the entry of spermatozoa into an apoptosis-like cascade characterized by the mitochondrial generation of reactive oxygen species. This oxidative stress may be exacerbated by a decline in local antioxidant protection, particularly during epididymal maturation. Finally, if oxidative stress is a major cause of sperm DNA damage then antioxidants should have an important therapeutic role to play in the clinical management of male infertility. Carefully controlled studies are now needed to critically examine this possibility.

Oxidative mechanisms contributing to the developmental neurotoxicity of nicotine and chlorpyrifos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, Dan; Seidler, Frederic J.; Slotkin, Theodore A.

Nicotine and chlorpyrifos are developmental neurotoxicants that, despite their differences in structure and mechanism of action, share many aspects for damage to the developing brain. Both are thought to generate oxidative radicals; in the current study, we evaluated their ability to produce lipid peroxidation in two in vitro models of neural cell development (PC12 and SH-SY5Y cells) and for nicotine, with treatment of adolescent rats in vivo. Nicotine and chlorpyrifos, in concentrations relevant to human exposures, elicited an increase in thiobarbituric-acid-reactive species (TBARS) in undifferentiated cells, an effect that was prevented by addition of the antioxidant, Vitamin E. Initiating differentiationmore » with nerve growth factor, which enhances nicotinic acetylcholine receptor expression, increased the TBARS response to nicotine but not chlorpyrifos, suggesting that the two agents act by different originating mechanisms to converge on the endpoint of oxidative damage. Furthermore, nicotine protected the cells from oxidative damage evoked by chlorpyrifos and similarly blocked the antimitotic effect of chlorpyrifos. Treatment of adolescent rats with nicotine elicited increases in TBARS in multiple brain regions when given in doses that simulate plasma nicotine concentrations found in smokers or at one-tenth the dose. Our results indicate that nicotine and chlorpyrifos elicit oxidative damage to developing neural cells both in vitro and in vivo, a mechanism that explains some of the neurodevelopmental endpoints that are common to the two agents. The balance between neuroprotectant and neurotoxicant actions of nicotine may be particularly important in situations where exposure to tobacco smoke is combined with other prooxidant insults.« less

Photooxidative damage in retinal pigment epithelial cells via GRP78 and the protective role of grape skin polyphenols.

PubMed

Zhao, Zhao; Sun, Tao; Jiang, Yun; Wu, Lijiang; Cai, Xiangzhong; Sun, Xiaodong; Sun, Xiangjun

2014-12-01

Blue light induced oxidative damage and ER stress are related to the pathogenesis of age-related macular degeneration (AMD). However, the mechanism of blue light-induced damage remained obscure. The objective of this work is to assess the photooxidative damage to retinal pigment epithelial cells (RPE) and oxidation-induced changes in expression of ER stress associated apoptotic proteins, and investigate the mechanism underlying the protective effects of grape skin extracts. To mimic lipofuscin-mediated photooxidation in vivo, ARPE-19 cells that accumulated A2E, one of lipofuscin fluorophores, were used as a model system to investigate the mechanism of photooxidative damage and the protective effects of grape skin polyphenols. Exposure of A2E containing ARPE-19 cells to blue light resulted in significant apoptosis and increases in levels of GRP78, CHOP, p-JNK, Bax, cleaved caspase-9, and cleaved caspase-3, indicating that photooxidative damage to RPE cells is mediated by the ER-stress-induced intrinsic apoptotic pathway. Cells in which GRP78 had been knocked down with shRNA were more vulnerable to photooxidative damage. Pre-treatment of blue-light-exposed A2E containing ARPE-19 cells, with grape skin extracts, inhibited apoptosis, in a dose dependent manner. Knockdown GRP78 blocked the protective effect of grape skin extracts.

Linalool prevents oxidative stress activated protein kinases in single UVB-exposed human skin cells

PubMed Central

Govindasamy, Kanimozhi; Ramasamy, Karthikeyan; Muthusamy, Ganesan; Shanmugam, Mohana; Thangaiyan, Radhiga; Robert, Beaulah Mary; Ponniresan, Veeramani kandan; Rathinaraj, Pierson

2017-01-01

Ultraviolet-B radiation (285–320 nm) elicits a number of cellular signaling elements. We investigated the preventive effect of linalool, a natural monoterpene, against UVB-induced oxidative imbalance, activation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling in HDFa cells. We observed that linalool treatment (30 μM) prevented acute UVB-irradiation (20 mJ/cm2) mediated loss of activities of antioxidant enzymes in HDFa cells. The comet assay results illustrate that linalool significantly prevents UVB-mediated 8-deoxy guanosine formation (oxidative DNA damage) rather than UVB-induced cyclobutane pyrimidine (CPD) formation. This might be due to its ability to prevent UVB-induced ROS formation and to restore the oxidative imbalance of cells. This has been reflected in UVB-induced overexpression of MAPK and NF-κB signaling. We observed that linalool inhibited UVB-induced phosphorylation of ERK1, JNK and p38 proteins of MAPK family. Linalool inhibited UVB-induced activation of NF-κB/p65 by activating IκBa. We further observed that UVB-induced expression of TNF-α, IL6, IL-10, MMP-2 and MMP-9 was modulated by linalool treatment in HDFa cells. Thus, linalool protects the human skin cells from the oxidative damages of UVB radiation and modulates MAPK and NF-κB signaling in HDFa cells. The present findings substantiate that linalool may act as a photoprotective agent against UVB-induced skin damages. PMID:28467450

Nitric oxide-mediated oxidative damage and the progressive demise of motor neurons in ALS.

PubMed

Drechsel, Derek A; Estévez, Alvaro G; Barbeito, Luis; Beckman, Joseph S

2012-11-01

Oxidative damage is a common and early feature of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS), and other neurodegenerative disorders. Dr. Mark Smith and his colleagues have built the case for oxidative stress being a primary progenitor rather than a secondary end-stage epiphenomenon of neurodegeneration. They proposed that reactive oxygen species contribute to the "age-related cascade of neurodegeneration," whereby accumulative oxidative damage with age promotes other characteristic pathological changes in afflicted brain regions, including protein aggregation, metabolic deficiencies, and inflammation. Nitric oxide (NO) likely plays a critical role in this age-related cascade. NO is a major signaling molecule produced in the central nervous system to modulate neurological activity through stimulating cyclic GMP synthesis. However, the same physiological concentrations of NO, relevant in cellular signaling, may also initiate and amplify oxidative damage by diffusion-limited reactions with superoxide (O(2)(•-)) to produce peroxynitrite (ONOO(-)). This is perhaps best illustrated in ALS where physiological levels of NO promote survival of motor neurons, but the same concentrations can stimulate motor neuron apoptosis and glial cell activation under pathological conditions. While these changes represent a complex mechanism involving multiple cell types in the pathogenesis of ALS, they also reveal general processes underlying neurodegeneration.

Higher levels of oxidative DNA damage in cervical cells are correlated with the grade of dysplasia and HPV infection.

PubMed

Visalli, Giuseppa; Riso, Romana; Facciolà, Alessio; Mondello, Placido; Caruso, Carmela; Picerno, Isa; Di Pietro, Angela; Spataro, Pasquale; Bertuccio, Maria Paola

2016-02-01

The Human papillomavirus is responsible for the most common sexually transmitted infection and is also known to be an oncogenic virus that is associated with cervical, anogenital, and head-neck cancers. The present study aims to assess whether oxidative DNA damage is correlated with the grade of HPV-related lesions. Moreover, we evaluated clinical data and unhealthy lifestyles to verify their possible influence on the genesis of oxidative DNA damage in cervical cells. We quantified the amount of 8-Oxo-2'-deoxyguanosine in DNA as a biomarker of oxidative damage in women with and without HPV infection. We also correlated oxidative damage with different stages of cervical lesions and available clinical data (e.g., HPV genotypes). To identify HPV infections, in which proteins with a transforming potential are produced, we performed a qualitative detection of HPV E6/E7 mRNA. Our results showed greater oxidative damage in HPV-related dysplastic cervical lesions compared to samples with normal cytology, especially in women with high-grade squamous intraepithelial lesions. The latter showed a closed link with high-risk HPV genotypes. Reactive oxygen species can induce DNA double-strand breaks in both the host DNA and in the circular viral episome; this could facilitate the integration of the virus, promoting HPV carcinogenesis. Therefore, in HPV-infected women, it could be useful to reduce additional resources of reactive oxygen/nitrogen species (RONS) with a healthy lifestyle. © 2015 Wiley Periodicals, Inc.

The molecular chaperone Hsp70 promotes the proteolytic removal of oxidatively damaged proteins by the proteasome

PubMed Central

Reeg, Sandra; Jung, Tobias; Castro, José P.; Davies, Kelvin J.A.; Henze, Andrea; Grune, Tilman

2016-01-01

One hallmark of aging is the accumulation of protein aggregates, promoted by the unfolding of oxidized proteins. Unraveling the mechanism by which oxidized proteins are degraded may provide a basis to delay the early onset of features, such as protein aggregate formation, that contribute to the aging phenotype. In order to prevent aggregation of oxidized proteins, cells recur to the 20S proteasome, an efficient turnover proteolysis complex. It has previously been shown that upon oxidative stress the 26S proteasome, another form, dissociates into the 20S form. A critical player implicated in its dissociation is the Heat Shock Protein 70 (Hsp70), which promotes an increase in free 20S proteasome and, therefore, an increased capability to degrade oxidized proteins. The aim of this study was to test whether or not Hsp70 is involved in cooperating with the 20S proteasome for a selective degradation of oxidatively damaged proteins. Our results demonstrate that Hsp70 expression is induced in HT22 cells as a result of mild oxidative stress conditions. Furthermore, Hsp70 prevents the accumulation of oxidized proteins and directly promotes their degradation by the 20S proteasome. In contrast the expression of the Heat shock cognate protein 70 (Hsc70) was not changed in recovery after oxidative stress and Hsc70 has no influence on the removal of oxidatively damaged proteins. We were able to demonstrate in HT22 cells, in brain homogenates from 129/SV mice and in vitro, that there is an increased interaction of Hsp70 with oxidized proteins, but also with the 20S proteasome, indicating a role of Hsp70 in mediating the interaction of oxidized proteins with the 20S proteasome. Thus, our data clearly implicate an involvement of Hsp70 oxidatively damaged protein degradation by the 20S proteasome. PMID:27498116

The molecular chaperone Hsp70 promotes the proteolytic removal of oxidatively damaged proteins by the proteasome.

PubMed

Reeg, Sandra; Jung, Tobias; Castro, José P; Davies, Kelvin J A; Henze, Andrea; Grune, Tilman

2016-10-01

One hallmark of aging is the accumulation of protein aggregates, promoted by the unfolding of oxidized proteins. Unraveling the mechanism by which oxidized proteins are degraded may provide a basis to delay the early onset of features, such as protein aggregate formation, that contribute to the aging phenotype. In order to prevent aggregation of oxidized proteins, cells recur to the 20S proteasome, an efficient turnover proteolysis complex. It has previously been shown that upon oxidative stress the 26S proteasome, another form, dissociates into the 20S form. A critical player implicated in its dissociation is the Heat Shock Protein 70 (Hsp70), which promotes an increase in free 20S proteasome and, therefore, an increased capability to degrade oxidized proteins. The aim of this study was to test whether or not Hsp70 is involved in cooperating with the 20S proteasome for a selective degradation of oxidatively damaged proteins. Our results demonstrate that Hsp70 expression is induced in HT22 cells as a result of mild oxidative stress conditions. Furthermore, Hsp70 prevents the accumulation of oxidized proteins and directly promotes their degradation by the 20S proteasome. In contrast the expression of the Heat shock cognate protein 70 (Hsc70) was not changed in recovery after oxidative stress and Hsc70 has no influence on the removal of oxidatively damaged proteins. We were able to demonstrate in HT22 cells, in brain homogenates from 129/SV mice and in vitro, that there is an increased interaction of Hsp70 with oxidized proteins, but also with the 20S proteasome, indicating a role of Hsp70 in mediating the interaction of oxidized proteins with the 20S proteasome. Thus, our data clearly implicate an involvement of Hsp70 oxidatively damaged protein degradation by the 20S proteasome. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

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

PubMed

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.

Cell signaling by reactive nitrogen and oxygen species in atherosclerosis

NASA Technical Reports Server (NTRS)

Patel, R. P.; Moellering, D.; Murphy-Ullrich, J.; Jo, H.; Beckman, J. S.; Darley-Usmar, V. M.

2000-01-01

The production of reactive oxygen and nitrogen species has been implicated in atherosclerosis principally as means of damaging low-density lipoprotein that in turn initiates the accumulation of cholesterol in macrophages. The diversity of novel oxidative modifications to lipids and proteins recently identified in atherosclerotic lesions has revealed surprising complexity in the mechanisms of oxidative damage and their potential role in atherosclerosis. Oxidative or nitrosative stress does not completely consume intracellular antioxidants leading to cell death as previously thought. Rather, oxidative and nitrosative stress have a more subtle impact on the atherogenic process by modulating intracellular signaling pathways in vascular tissues to affect inflammatory cell adhesion, migration, proliferation, and differentiation. Furthermore, cellular responses can affect the production of nitric oxide, which in turn can strongly influence the nature of oxidative modifications occurring in atherosclerosis. The dynamic interactions between endogenous low concentrations of oxidants or reactive nitrogen species with intracellular signaling pathways may have a general role in processes affecting wound healing to apoptosis, which can provide novel insights into the pathogenesis of atherosclerosis.

Polymyxin B Nephrotoxicity: From Organ to Cell Damage

PubMed Central

Pessoa, Edson Andrade

2016-01-01

Polymyxins have a long history of dose-limiting toxicity, but the underlying mechanism of polymyxin B-induced nephrotoxicity is unclear. This study investigated the link between the nephrotoxic effects of polymyxin B on renal metabolic functions and mitochondrial morphology in rats and on the structural integrity of LLC-PK1 cells. Fifteen Wistar rats were divided into two groups: Saline group, rats received 3 mL/kg of 0.9% NaCl intraperitoneally (i.p.) once a day for 5 days; Polymyxin B group, rats received 4 mg/kg/day of polymyxin B i.p. once a day for 5 days. Renal function, renal hemodynamics, oxidative stress, mitochondrial injury and histological characteristics were assessed. Cell membrane damage was evaluated via lactate dehydrogenase and nitric oxide levels, cell viability, and apoptosis in cells exposed to 12.5 μM, 75 μM and 375 μM polymyxin B. Polymyxin B was immunolocated using Lissamine rhodamine-polymyxin B in LLC-PK1 cells. Polymyxin B administration in rats reduced creatinine clearance and increased renal vascular resistance and oxidative damage. Mitochondrial damage was confirmed by electron microscopy and cytosolic localization of cytochrome c. Histological analysis revealed tubular dilatation and necrosis in the renal cortex. The reduction in cell viability and the increase in apoptosis, lactate dehydrogenase levels and nitric oxide levels confirmed the cytotoxicity of polymyxin B. The incubation of LLC-PK1 cells resulted in mitochondrial localization of polymyxin B. This study demonstrates that polymyxin B nephrotoxicity is characterized by mitochondrial dysfunction and free radical generation in both LLC-PK1 cells and rat kidneys. These data also provide support for clinical studies on the side effects of polymyxin B. PMID:27532263

Study of the Genes and Mechanism Involved in the Radioadaptive Response

NASA Technical Reports Server (NTRS)

Dasgupta, Pushan R.

2009-01-01

The radioadaptive response is a phenomenon where exposure to a prior low dose of radiation reduces the level of damage induced by a subsequent high radiation dose. The molecular mechanism behind this is still not well understood. Learning more about the radioadaptive response is critical for long duration spaceflight since astronauts are exposed to low levels of cosmic radiation. The micronucleus assay was used to measure the level of damage caused by radiation. Although cells which were not washed with phosphate buffered saline (PBS) after a low priming dose of 5cGy did not show adaptation to the challenge dose, washing the cells with PBS and giving the cells fresh media after the low dose did allow radioadaptation to occur. This is consistent with the results of a previous publication by another research group. In the present study, genes involved in DNA damage signaling and the oxidative stress response were studied using RT PCR techniques in order to look at changes in expression level after the low dose with or without washing. Our preliminary results indicate that upregulation of oxidative stress response genes ANGPTL7, NCF2, TTN, and SRXN1 may be involved in the radioadaptive response. The low dose of radiation alone was found to activate the oxidative stress response genes GPR156 and MTL5, whereas, washing the cells alone caused relatively robust upregulation of the oxidative stress response genes DUSP1 and PTGS2. Washing after the priming dose showed some changes in the expression level of several DNA damage signaling genes. In addition, we studied whether washing the cells after the priming dose has an effect on the level of nitric oxide in both the media and cells, since nitric oxide levels are known to increase in the media of the cells after a high dose of radiation only if the cells were already exposed to a low priming dose. Based on this preliminary study, we propose that washing the cells after priming exposure actually eliminates some factor secreted by the cells that inhibits radioadaptation leading to the upregulation of some genes which initiates the response.

Protective Effects of Resveratrol against UVA-Induced Damage in ARPE19 Cells

PubMed Central

Chan, Chi-Ming; Huang, Cheng-Hua; Li, Hsin-Ju; Hsiao, Chien-Yu; Su, Ching-Chieh; Lee, Pei-Lan; Hung, Chi-Feng

2015-01-01

Ultraviolet radiation, especially UVA, can penetrate the lens, reach the retina, and induce oxidative stress to retinal pigment epithelial (RPE) cells. Even though it is weakly absorbed by protein and DNA, it may trigger the production of reactive oxygen species (ROS) and generate oxidative injury; oxidative injury to the retinal pigment epithelium has been implicated to play a contributory role in age-related macular degeneration (AMD). Studies showed that resveratrol, an abundant and active component of red grapes, can protect several cell types from oxidative stress. In this study, adult RPE cells being treated with different concentrations of resveratrol were used to evaluate the protective effect of resveratrol on RPE cells against UVA-induced damage. Cell viability assay showed that resveratrol reduced the UVA-induced decrease in RPE cell viability. Through flow cytometry analysis, we found that the generation of intracellular H2O2 induced by UVA irradiation in RPE cells could be suppressed by resveratrol in a concentration-dependent manner. Results of Western blot analysis demonstrated that resveratrol lowered the activation of UVA-induced extracellular signal-regulated kinase, c-jun-NH2 terminal kinase and p38 kinase in RPE cells. In addition, there was also a reduction in UVA-induced cyclooxygenase-2 (COX-2) expression in RPE cells pretreated with resveratrol. Our observations suggest that resveratrol is effective in preventing RPE cells from being damaged by UVA radiation, and is worth considering for further development as a chemoprotective agent for the prevention of early AMD. PMID:25775159

Protective effects of resveratrol against UVA-induced damage in ARPE19 cells.

PubMed

Chan, Chi-Ming; Huang, Cheng-Hua; Li, Hsin-Ju; Hsiao, Chien-Yu; Su, Ching-Chieh; Lee, Pei-Lan; Hung, Chi-Feng

2015-03-12

Ultraviolet radiation, especially UVA, can penetrate the lens, reach the retina, and induce oxidative stress to retinal pigment epithelial (RPE) cells. Even though it is weakly absorbed by protein and DNA, it may trigger the production of reactive oxygen species (ROS) and generate oxidative injury; oxidative injury to the retinal pigment epithelium has been implicated to play a contributory role in age-related macular degeneration (AMD). Studies showed that resveratrol, an abundant and active component of red grapes, can protect several cell types from oxidative stress. In this study, adult RPE cells being treated with different concentrations of resveratrol were used to evaluate the protective effect of resveratrol on RPE cells against UVA-induced damage. Cell viability assay showed that resveratrol reduced the UVA-induced decrease in RPE cell viability. Through flow cytometry analysis, we found that the generation of intracellular H2O2 induced by UVA irradiation in RPE cells could be suppressed by resveratrol in a concentration-dependent manner. Results of Western blot analysis demonstrated that resveratrol lowered the activation of UVA-induced extracellular signal-regulated kinase, c-jun-NH2 terminal kinase and p38 kinase in RPE cells. In addition, there was also a reduction in UVA-induced cyclooxygenase-2 (COX-2) expression in RPE cells pretreated with resveratrol. Our observations suggest that resveratrol is effective in preventing RPE cells from being damaged by UVA radiation, and is worth considering for further development as a chemoprotective agent for the prevention of early AMD.

Oxidative damage and cell-programmed death induced in Zea mays L. by allelochemical stress.

PubMed

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.

Cryopreservation of human blood for alkaline and Fpg-modified comet assay.

PubMed

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

2016-01-01

The Comet assay is a reproducible and sensitive assay for the detection of DNA damage in eukaryotic cells and tissues. Incorporation of lesion specific, oxidative DNA damage repair enzymes (for example, Fpg, OGG1 and EndoIII) in the standard alkaline Comet assay procedure allows for the detection and measurement of oxidative DNA damage. The Comet assay using white blood cells (WBC) has proven useful in monitoring DNA damage from environmental agents in humans. However, it is often impractical to performance Comet assay immediately after blood sampling. Thus, storage of blood sample is required. In this study, we developed and tested a simple storage method for very small amount of whole blood for standard and Fpg-modified modified Comet assay. Whole blood was stored in RPMI 1640 media containing 10% FBS, 10% DMSO and 1 mM deferoxamine at a sample to media ratio of 1:50. Samples were stored at -20 °C and -80 °C for 1, 7, 14 and 28 days. Isolated lymphocytes from the same subjects were also stored under the same conditions for comparison. Direct DNA strand breakage and oxidative DNA damage in WBC and lymphocytes were analyzed using standard and Fpg-modified alkaline Comet assay and compared with freshly analyzed samples. No significant changes in either direct DNA strand breakage or oxidative DNA damage was seen in WBC and lymphocytes stored at -20 °C for 1 and 7 days compared to fresh samples. However, significant increases in both direct and oxidative DNA damage were seen in samples stored at -20 °C for 14 and 28 days. No changes in direct and oxidative DNA damage were observed in WBC and lymphocytes stored at -80 °C for up to 28 days. These results identified the proper storage conditions for storing whole blood or isolated lymphocytes to evaluate direct and oxidative DNA damage using standard and Fpg-modified alkaline Comet assay.

Withaferin A Induces Oxidative Stress-Mediated Apoptosis and DNA Damage in Oral Cancer Cells.

PubMed

Chang, Hsueh-Wei; Li, Ruei-Nian; Wang, Hui-Ru; Liu, Jing-Ru; Tang, Jen-Yang; Huang, Hurng-Wern; Chan, Yu-Hsuan; Yen, Ching-Yu

2017-01-01

Withaferin A (WFA) is one of the most active steroidal lactones with reactive oxygen species (ROS) modulating effects against several types of cancer. ROS regulation involves selective killing. However, the anticancer and selective killing effects of WFA against oral cancer cells remain unclear. We evaluated whether the killing ability of WFA is selective, and we explored its mechanism against oral cancer cells. An MTS tetrazolium cell proliferation assay confirmed that WFA selectively killed two oral cancer cells (Ca9-22 and CAL 27) rather than normal oral cells (HGF-1). WFA also induced apoptosis of Ca9-22 cells, which was measured by flow cytometry for subG1 percentage, annexin V expression, and pan-caspase activity, as well as western blotting for caspases 1, 8, and 9 activations. Flow cytometry analysis shows that WFA-treated Ca9-22 oral cancer cells induced G2/M cell cycle arrest, ROS production, mitochondrial membrane depolarization, and phosphorylated histone H2A.X (γH2AX)-based DNA damage. Moreover, pretreating Ca9-22 cells with N -acetylcysteine (NAC) rescued WFA-induced selective killing, apoptosis, G2/M arrest, oxidative stress, and DNA damage. We conclude that WFA induced oxidative stress-mediated selective killing of oral cancer cells.

Withaferin A Induces Oxidative Stress-Mediated Apoptosis and DNA Damage in Oral Cancer Cells

PubMed Central

Chang, Hsueh-Wei; Li, Ruei-Nian; Wang, Hui-Ru; Liu, Jing-Ru; Tang, Jen-Yang; Huang, Hurng-Wern; Chan, Yu-Hsuan; Yen, Ching-Yu

2017-01-01

Withaferin A (WFA) is one of the most active steroidal lactones with reactive oxygen species (ROS) modulating effects against several types of cancer. ROS regulation involves selective killing. However, the anticancer and selective killing effects of WFA against oral cancer cells remain unclear. We evaluated whether the killing ability of WFA is selective, and we explored its mechanism against oral cancer cells. An MTS tetrazolium cell proliferation assay confirmed that WFA selectively killed two oral cancer cells (Ca9-22 and CAL 27) rather than normal oral cells (HGF-1). WFA also induced apoptosis of Ca9-22 cells, which was measured by flow cytometry for subG1 percentage, annexin V expression, and pan-caspase activity, as well as western blotting for caspases 1, 8, and 9 activations. Flow cytometry analysis shows that WFA-treated Ca9-22 oral cancer cells induced G2/M cell cycle arrest, ROS production, mitochondrial membrane depolarization, and phosphorylated histone H2A.X (γH2AX)-based DNA damage. Moreover, pretreating Ca9-22 cells with N-acetylcysteine (NAC) rescued WFA-induced selective killing, apoptosis, G2/M arrest, oxidative stress, and DNA damage. We conclude that WFA induced oxidative stress-mediated selective killing of oral cancer cells. PMID:28936177

SC79 protects retinal pigment epithelium cells from UV radiation via activating Akt-Nrf2 signaling

PubMed Central

Cao, Guo-fan; Cao, Cong; Jiang, Qin

2016-01-01

Excessive Ultra-violet (UV) radiation causes oxidative damages and apoptosis in retinal pigment epithelium (RPE) cells. Here we tested the potential activity of SC79, a novel small molecule activator of Akt, against the process. We showed that SC79 activated Akt in primary and established (ARPE-19 line) RPE cells. It protected RPE cells from UV damages possibly via inhibiting cell apoptosis. Akt inhibition, via an Akt specific inhibitor (MK-2206) or Akt1 shRNA silence, almost abolished SC79-induced RPE cytoprotection. Further studies showed that SC79 activated Akt-dependent NF-E2-related factor 2 (Nrf2) signaling and inhibited UV-induced oxidative stress in RPE cells. Reversely, Nrf2 shRNA knockdown or S40T mutation attenuated SC79-induced anti-UV activity. For the in vivo studies, we showed that intravitreal injection of SC79 significantly protected mouse retina from light damages. Based on these results, we suggest that SC79 protects RPE cells from UV damages possibly via activating Akt-Nrf2 signaling axis. PMID:27517753

Effects of oxidative stress-induced changes in the actin cytoskeletal structure on myoblast damage under compressive stress: confocal-based cell-specific finite element analysis.

PubMed

Yao, Yifei; Lacroix, Damien; Mak, Arthur F T

2016-12-01

Muscle cells are frequently subjected to both mechanical and oxidative stresses in various physiological and pathological situations. To explore the mechanical mechanism of muscle cell damage under loading and oxidative stresses, we experimentally studied the effects of extrinsic hydrogen peroxides on the actin cytoskeletal structure in C2C12 myoblasts and presented a finite element (FE) analysis of how such changes in the actin cytoskeletal structure affected a myoblast's capability to resist damage under compression. A confocal-based cell-specific FE model was built to parametrically study the effects of stress fiber density, fiber cross-sectional area, fiber tensile prestrain, as well as the elastic moduli of the stress fibers, actin cortex, nucleus and cytoplasm. The results showed that a decrease in the elastic moduli of both the stress fibers and actin cortex could increase the average tensile strain on the actin cortex-membrane structure and reduce the apparent cell elastic modulus. Assuming the cell would die when a certain percentage of membrane elements were strained beyond a threshold, a lower elastic modulus of actin cytoskeleton would compromise the compressive resistance of a myoblast and lead to cell death more readily. This model was used with a Weibull distribution function to successfully describe the extent of myoblasts damaged in a monolayer under compression.

Oxidative DNA Base Damage in MCF-10A Breast Epithelial Cells at Clinically Achievable Concentrations of Doxorubicin

PubMed Central

Gajewski, Ewa; Gaur, Shikha; Akman, Steven A.; Matsumoto, Linda; van Balgooy, Josephus N.A.; Doroshow, James H.

2009-01-01

The cellular metabolism of doxorubicin generates reactive oxygen species with significant potential to damage DNA. Such DNA damage can result in mutations if not adequately repaired by cellular DNA repair pathways. Secondary malignancies have been reported in patients who have received doxorubicin-containing chemotherapeutic regimens; however, the underlying molecular mechanism(s) to explain the development of these tumors remains under active investigation. We have previously demonstrated the presence of DNA bases modified by oxidation in the peripheral blood mononuclear cells of patients with breast cancer following treatment with doxorubicin. In those studies, doxorubicin was administered by continuous infusion over 96 hours to minimize the risk of cardiac toxicity. To evaluate potential mechanisms underlying doxorubicin-induced DNA base oxidation in non-malignant tissues, MCF-10A breast epithelial cells were cultured for 96 hours with the same doxorubicin concentration achieved in vivo (0.1 μM). During doxorubicin exposure, MCF-10A cells underwent growth arrest and apoptosis, developed elevated levels of reactive oxygen species, and demonstrated a time-dependent and significant increase in the levels of 11 oxidized DNA bases, as determined by gas chromatography/mass spectroscopy. Diminished expression of DNA repair enzymes was also observed over the same time course. Thus, clinically achievable concentrations of doxorubicin induce a level of oxidative stress in MCF-10A cells that is capable of oxidizing DNA bases and significantly altering cellular proliferation. PMID:17445777

Oxidative DNA damage background estimated by a system model of base excision repair

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sokhansanj, B A; Wilson, III, D M

Human DNA can be damaged by natural metabolism through free radical production. It has been suggested that the equilibrium between innate damage and cellular DNA repair results in an oxidative DNA damage background that potentially contributes to disease and aging. Efforts to quantitatively characterize the human oxidative DNA damage background level based on measuring 8-oxoguanine lesions as a biomarker have led to estimates varying over 3-4 orders of magnitude, depending on the method of measurement. We applied a previously developed and validated quantitative pathway model of human DNA base excision repair, integrating experimentally determined endogenous damage rates and model parametersmore » from multiple sources. Our estimates of at most 100 8-oxoguanine lesions per cell are consistent with the low end of data from biochemical and cell biology experiments, a result robust to model limitations and parameter variation. Our results show the power of quantitative system modeling to interpret composite experimental data and make biologically and physiologically relevant predictions for complex human DNA repair pathway mechanisms and capacity.« less

Modification of smoke toxicant yields alters the effects of cigarette smoke extracts on endothelial migration: an in vitro study using a cardiovascular disease model.

PubMed

Fearon, Ian M; Acheampong, Daniel O; Bishop, Emma

2012-01-01

Endothelial damage plays a key role in atherosclerosis and this is impacted upon by numerous risk factors including cigarette smoking. A potential measure to reduce the cardiovascular burden associated with smoking is to reduce smoke toxicant exposure. In an in vitro endothelial damage repair assay, endothelial cell migration was inhibited by cigarette smoke particulate matter (PM) generated from several cigarette types. This inhibition was reduced when cells were exposed to PM from an experimental cigarette with reduced smoke toxicant levels. As a number of toxicants induce oxidative stress and since oxidative stress may link cigarette smoke and endothelial damage, we hypothesized that PM effects were dependent on elevated cellular oxidants. However, although PM-induced cellular oxidant production could be inhibited by ascorbic acid or n-acetylcysteine, both these antioxidants were without effect on migration responses to PM. Furthermore, reactive oxygen species production, as indicated by dihydroethidium fluorescence, was not different in cells exposed to smoke from cigarettes with different toxicant levels. In summary, our data demonstrate that a cardiovascular disease-related biological response may be modified when cells are exposed to smoke containing different levels of toxicants. This appeared independent of the induction of oxidative stress.

Telomere attrition and genomic instability in xeroderma pigmentosum type-b deficient fibroblasts under oxidative stress

PubMed Central

Ting, Aloysius Poh Leong; Low, Grace Kah Mun; Gopalakrishnan, Kalpana; Hande, M Prakash

2010-01-01

Abstract Xeroderma pigmentosum B (XPB/ERCC3/p89) is an ATP-dependent 3′→5′ directed DNA helicase involved in basal RNA transcription and the nucleotide excision repair (NER) pathway. While the role of NER in alleviating oxidative DNA damage has been acknowledged it remains poorly understood. To study the involvement of XPB in repair of oxidative DNA damage, we utilized primary fibroblasts from a patient suffering from XP with Cockayne syndrome and hydrogen peroxide (H2O2) to induce oxidative stress. Mutant cells retained higher viability and cell cycle dysfunction after H2O2 exposure. Cytokinesis blocked micronucleus assay revealed increased genome instability induced by H2O2. Single cell gel electrophoresis (comet) assay showed that the missense mutation caused a reduced repair capacity for oxidative DNA damage. Mutant fibroblasts also displayed decreased population doubling rate, increased telomere attrition rate and early emergence of senescent characteristics under chronic low dose exposure to H2O2. Fibroblasts from a heterozygous individual displayed intermediate traits in some assays and normal traits in others, indicating possible copy number dependence. The results show that a deficiency in functional XPB paradoxically renders cells more sensitive to the genotoxic effects of oxidative stress while reducing the cytotoxic effects. These findings have implications in the mechanisms of DNA repair, mutagenesis and carcinogenesis and ageing in normal physiological systems. PMID:19840190

RECQL4-deficient cells are hypersensitive to oxidative stress/damage: Insights for osteosarcoma prevalence and heterogeneity in Rothmund-Thomson syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Werner, Sean R.; Prahalad, Agasanur K.; Yang Jieping

2006-06-23

Rothmund-Thomson syndrome (RTS) is a heterogeneous disease, associated with increased prevalence of osteosarcoma in very young patients with a mutated RECQL4 gene. In this study, we tested the ability of RECQL4 deficient fibroblasts, derived from a RTS patient to recover from hydrogen peroxide (H{sub 2}O{sub 2})-induced oxidative stress/damage. Immunoperoxidase staining for 8-oxo-deoxyguanosine (8-oxo-dG) formation in RTS and normal human fibroblasts were compared to assess DNA damage. We determined DNA synthesis, cell growth, cell cycle distribution, and viability in RTS and normal human fibroblasts before and after H{sub 2}O{sub 2} treatment. H{sub 2}O{sub 2} induces 8-oxo-dG formation in both RTS andmore » normal fibroblasts. In normal human fibroblasts, RECQL4 was predominantly localized to cytoplasm; nuclear translocation and foci formation occurred in response to oxidant stimulation. After recovery from oxidant exposure, viable RTS fibroblasts showed irreversible growth arrest compared to normal fibroblasts. DNA synthesis decreased significantly in treated RTS cells, with concomitant reduction of cells in the S-phase. These results suggest that enhanced oxidant sensitivity in RECQL4 deficient fibroblasts derived from RTS patients could be attributed to abnormal DNA metabolism and proliferation failure. The ramifications of these findings on osteosarcoma prevalence and heterogeneity in RTS are discussed.« less

Evaluation of Toxic Effects of Aeration and Trichloroethylene Oxidation on Methanotrophic Bacteria Grown with Different Nitrogen Sources

PubMed Central

Chu, Kung-Hui; Alvarez-Cohen, Lisa

1999-01-01

In this study we evaluated specific and nonspecific toxic effects of aeration and trichloroethylene (TCE) oxidation on methanotrophic bacteria grown with different nitrogen sources (nitrate, ammonia, and molecular nitrogen). The specific toxic effects, exerted directly on soluble methane monooxygenase (sMMO), were evaluated by comparing changes in methane uptake rates and naphthalene oxidation rates following aeration and/or TCE oxidation. Nonspecific toxic effects, defined as general cellular damage, were examined by using a combination of epifluorescent cellular stains to measure viable cell numbers based on respiratory activity and measuring formate oxidation activities following aeration and TCE transformation. Our results suggest that aeration damages predominantly sMMO rather than other general cellular components, whereas TCE oxidation exerts a broad range of toxic effects that damage both specific and nonspecific cellular functions. TCE oxidation caused sMMO-catalyzed activity and respiratory activity to decrease linearly with the amount of substrate degraded. Severe TCE oxidation toxicity resulted in total cessation of the methane, naphthalene, and formate oxidation activities and a 95% decrease in the respiratory activity of methanotrophs. The failure of cells to recover even after 7 days of incubation with methane suggests that cellular recovery following severe TCE product toxicity is not always possible. Our evidence suggests that generation of greater amounts of sMMO per cell due to nitrogen fixation may be responsible for enhanced TCE oxidation activities of nitrogen-fixing methanotrophs rather than enzymatic protection mechanisms associated with the nitrogenase enzymes. PMID:9925614

Sublethal Total Body Irradiation Leads to Early Cerebellar Damage and Oxidative Stress

DTIC Science & Technology

2010-01-01

mice: protective effect of alpha - lipoic acid . Behav Brain Res 2007b; 177(1): 7-14. [8] Manda K, Ueno M, Anzai K. Melatonin mitigates oxidative...Memory impairment, oxidative damage and apoptosis induced by space radiation: ameliorative potential of alpha - lipoic acid . Behav Brain Res 2008b...1977; 171(1): 39-50. [6] Manda K, Ueno M, Moritake T, Anzai K. - Lipoic acid attenuates x-irradiation-induced oxidative stress in mice. Cell Biol

Oxidative Stress Mechanisms Do Not Discriminate between Genotoxic and Nongenotoxic Liver Carcinogens.

PubMed

Deferme, Lize; Wolters, Jarno; Claessen, Sandra; Briedé, Jacco; Kleinjans, Jos

2015-08-17

It is widely accepted that in chemical carcinogenesis different modes-of-action exist, e.g., genotoxic (GTX) versus nongenotoxic (NGTX) carcinogenesis. In this context, it has been suggested that oxidative stress response pathways are typical for NGTX carcinogenesis. To evaluate this, we examined oxidative stress-related changes in gene expression, cell cycle distribution, and (oxidative) DNA damage in human hepatoma cells (HepG2) exposed to GTX-, NGTX-, and noncarcinogens, at multiple time points (4-8-24-48-72 h). Two GTX (azathriopine (AZA) and furan) and two NGTX (tetradecanoyl-phorbol-acetate, (TPA) and tetrachloroethylene (TCE)) carcinogens as well as two noncarcinogens (diazinon (DZN, d-mannitol (Dman)) were selected, while per class one compound was deemed to induce oxidative stress and the other not. Oxidative stressors AZA, TPA, and DZN induced a 10-fold higher number of gene expression changes over time compared to those of furan, TCE, or Dman treatment. Genes commonly expressed among AZA, TPA, and DZN were specifically involved in oxidative stress, DNA damage, and immune responses. However, differences in gene expression between GTX and NGTX carcinogens did not correlate to oxidative stress or DNA damage but could instead be assigned to compound-specific characteristics. This conclusion was underlined by results from functional readouts on ROS formation and (oxidative) DNA damage. Therefore, oxidative stress may represent the underlying cause for increased risk of liver toxicity and even carcinogenesis; however, it does not discriminate between GTX and NGTX carcinogens.

Oxidation of DNA bases, deoxyribonucleosides and homopolymers by peroxyl radicals.

PubMed Central

Simandan, T; Sun, J; Dix, T A

1998-01-01

DNA base oxidation is considered to be a key event associated with disease initiation and progression in humans. Peroxyl radicals (ROO. ) are important oxidants found in cells whose ability to react with the DNA bases has not been characterized extensively. In this paper, the products resulting from ROO. oxidation of the DNA bases are determined by gas chromatography/MS in comparison with authentic standards. ROO. radicals oxidize adenine and guanine to their 8-hydroxy derivatives, which are considered biomarkers of hydroxyl radical (HO.) oxidations in cells. ROO. radicals also oxidize adenine to its hydroxylamine, a previously unidentified product. ROO. radicals oxidize cytosine and thymine to the monohydroxy and dihydroxy derivatives that are formed by oxidative damage in cells. Identical ROO. oxidation profiles are observed for each base when exposed as deoxyribonucleosides, monohomopolymers and base-paired dihomopolymers. These results have significance for the development, utilization and interpretation of DNA base-derived biomarkers of oxidative damage associated with disease initiation and propagation, and support the idea that the mutagenic potential of N-oxidized bases, when generated in cellular DNA, will require careful evaluation. Adenine hydroxylamine is proposed as a specific molecular probe for the activity of ROO. in cellular systems. PMID:9761719

H2S protects against methionine-induced oxidative stress in brain endothelial cells.

PubMed

Tyagi, Neetu; Moshal, Karni S; Sen, Utpal; Vacek, Thomas P; Kumar, Munish; Hughes, William M; Kundu, Soumi; Tyagi, Suresh C

2009-01-01

Homocysteine (Hcy) causes cerebrovascular dysfunction by inducing oxidative stress. However, to date, there are no strategies to prevent Hcy-induced oxidative damage. Hcy is an H2S precursor formed from methionine (Met) metabolism. We aimed to investigate whether H2S ameliorated Met-induced oxidative stress in mouse brain endothelial cells (bEnd3). The bEnd3 cells were exposed to Met treatment in the presence or absence of NaHS (donor of H2S). Met-induced cell toxicity increased the levels of free radicals in a concentration-dependent manner. Met increased NADPH-oxidase-4 (NOX-4) expression and mitigated thioredxion-1(Trx-1) expression. Pretreatment of bEnd3 with NaHS (0.05 mM) attenuated the production of free radicals in the presence of Met and protected the cells from oxidative damage. Furthermore, NaHS enhanced inhibitory effects of apocynin, N-acetyl-l-cysteine (NAC), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), Nomega-nitro-l-arginine methyl ester (L-NAME) on ROS production and redox enzymes levels induced by Met. In conclusion, the administration of H2S protected the cells from oxidative stress induced by hyperhomocysteinemia (HHcy), which suggested that NaHS/H2S may have therapeutic potential against Met-induced oxidative stress.

Novel Double-Hit Model of Radiation and Hyperoxia-Induced Oxidative Cell Damage Relevant to Space Travel

PubMed Central

Pietrofesa, Ralph A.; Velalopoulou, Anastasia; Lehman, Stacey L.; Arguiri, Evguenia; Solomides, Pantelis; Koch, Cameron J.; Mishra, Om P.; Koumenis, Constantinos; Goodwin, Thomas J.; Christofidou-Solomidou, Melpo

2016-01-01

Spaceflight occasionally requires multiple extravehicular activities (EVA) that potentially subject astronauts to repeated changes in ambient oxygen superimposed on those of space radiation exposure. We thus developed a novel in vitro model system to test lung cell damage following repeated exposure to radiation and hyperoxia. Non-tumorigenic murine alveolar type II epithelial cells (C10) were exposed to >95% O2 for 8 h only (O2), 0.25 Gy ionizing γ-radiation (IR) only, or a double-hit combination of both challenges (O2 + IR) followed by 16 h of normoxia (ambient air containing 21% O2 and 5% CO2) (1 cycle = 24 h, 2 cycles = 48 h). Cell survival, DNA damage, apoptosis, and indicators of oxidative stress were evaluated after 1 and 2 cycles of exposure. We observed a significant (p < 0.05) decrease in cell survival across all challenge conditions along with an increase in DNA damage, determined by Comet analysis and H2AX phosphorylation, and apoptosis, determined by Annexin-V staining, relative to cells unexposed to hyperoxia or radiation. DNA damage (GADD45α and cleaved-PARP), apoptotic (cleaved caspase-3 and BAX), and antioxidant (HO-1 and Nqo1) proteins were increased following radiation and hyperoxia exposure after 1 and 2 cycles of exposure. Importantly, exposure to combination challenge O2 + IR exacerbated cell death and DNA damage compared to individual exposures O2 or IR alone. Additionally levels of cell cycle proteins phospho-p53 and p21 were significantly increased, while levels of CDK1 and Cyclin B1 were decreased at both time points for all exposure groups. Similarly, proteins involved in cell cycle arrest was more profoundly changed with the combination challenges as compared to each stressor alone. These results correlate with a significant 4- to 6-fold increase in the ratio of cells in G2/G1 after 2 cycles of exposure to hyperoxic conditions. We have characterized a novel in vitro model of double-hit, low-level radiation and hyperoxia exposure that leads to oxidative lung cell injury, DNA damage, apoptosis, and cell cycle arrest. PMID:27322243

Novel Double-Hit Model of Radiation and Hyperoxia-Induced Oxidative Cell Damage Relevant to Space Travel.

PubMed

Pietrofesa, Ralph A; Velalopoulou, Anastasia; Lehman, Stacey L; Arguiri, Evguenia; Solomides, Pantelis; Koch, Cameron J; Mishra, Om P; Koumenis, Constantinos; Goodwin, Thomas J; Christofidou-Solomidou, Melpo

2016-06-16

Spaceflight occasionally requires multiple extravehicular activities (EVA) that potentially subject astronauts to repeated changes in ambient oxygen superimposed on those of space radiation exposure. We thus developed a novel in vitro model system to test lung cell damage following repeated exposure to radiation and hyperoxia. Non-tumorigenic murine alveolar type II epithelial cells (C10) were exposed to >95% O₂ for 8 h only (O₂), 0.25 Gy ionizing γ-radiation (IR) only, or a double-hit combination of both challenges (O₂ + IR) followed by 16 h of normoxia (ambient air containing 21% O₂ and 5% CO₂) (1 cycle = 24 h, 2 cycles = 48 h). Cell survival, DNA damage, apoptosis, and indicators of oxidative stress were evaluated after 1 and 2 cycles of exposure. We observed a significant (p < 0.05) decrease in cell survival across all challenge conditions along with an increase in DNA damage, determined by Comet analysis and H2AX phosphorylation, and apoptosis, determined by Annexin-V staining, relative to cells unexposed to hyperoxia or radiation. DNA damage (GADD45α and cleaved-PARP), apoptotic (cleaved caspase-3 and BAX), and antioxidant (HO-1 and Nqo1) proteins were increased following radiation and hyperoxia exposure after 1 and 2 cycles of exposure. Importantly, exposure to combination challenge O₂ + IR exacerbated cell death and DNA damage compared to individual exposures O₂ or IR alone. Additionally levels of cell cycle proteins phospho-p53 and p21 were significantly increased, while levels of CDK1 and Cyclin B1 were decreased at both time points for all exposure groups. Similarly, proteins involved in cell cycle arrest was more profoundly changed with the combination challenges as compared to each stressor alone. These results correlate with a significant 4- to 6-fold increase in the ratio of cells in G2/G1 after 2 cycles of exposure to hyperoxic conditions. We have characterized a novel in vitro model of double-hit, low-level radiation and hyperoxia exposure that leads to oxidative lung cell injury, DNA damage, apoptosis, and cell cycle arrest.

Regulation of replicative senescence by NADP+ -dependent isocitrate dehydrogenase.

PubMed

Kil, In Sup; Huh, Tae Lin; Lee, Young Sup; Lee, You Mie; Park, Jeen-Woo

2006-01-01

The free radical hypothesis of aging postulates that senescence is due to an accumulation of cellular oxidative damage, caused largely by reactive oxygen species that are produced as by-products of normal metabolic processes. Recently, we demonstrated that the control of cytosolic and mitochondrial redox balance and the cellular defense against oxidative damage is one of the primary functions of cytosolic (IDPc) and mitochondrial NADP+ -dependent isocitrate dehydrogenase (IDPm) by supplying NADPH for antioxidant systems. In this paper, we demonstrate that modulation of IDPc or IDPm activity in IMR-90 cells regulates cellular redox status and replicative senescence. When we examined the regulatory role of IDPc and IDPm against the aging process with IMR-90 cells transfected with cDNA for IDPc or IDPm in sense and antisense orientations, a clear inverse relationship was observed between the amount of IDPc or IDPm expressed in target cells and their susceptibility to senescence, which was reflected by changes in replicative potential, cell cycle, senescence-associated beta-galactosidase activity, expression of p21 and p53, and morphology of cells. Furthermore, lipid peroxidation, oxidative DNA damage, and intracellular peroxide generation were higher and cellular redox status shifted to a prooxidant condition in the cell lines expressing the lower level of IDPc or IDPm. The results suggest that IDPc and IDPm play an important regulatory role in cellular defense against oxidative stress and in the senescence of IMR-90 cells.

Ozone Inhalation Leads to a Dose-Dependent Increase of Cytogenetic Damage in Human Lymphocytes

PubMed Central

Holland, Nina; Davé, Veronica; Venkat, Subha; Wong, Hofer; Donde, Aneesh; Balmes, John R; Arjomandi, Mehrdad

2014-01-01

Ozone is an important constituent of ambient air pollution and represents a major public health concern. Oxidative injury due to ozone inhalation causes the generation of reactive oxygen species and can be genotoxic. To determine whether ozone exposure causes genetic damage in peripheral blood lymphocytes, we employed a well-validated cytokinesis-block micronucleus Cytome assay. Frequencies of micronuclei (MN) and nucleoplasmic bridges (NB) were used as indicators of cytogenetic damage. Samples were obtained from 22 non-smoking healthy subjects immediately before and 24-hr after controlled 4-hr exposures to filtered air, 100 ppb, and 200 ppb ozone while exercising in a repeated-measure study design. Inhalation of ozone at different exposure levels was associated with a significant dose-dependent increase in MN frequency (P < 0.0001) and in the number of cells with more than 1 MN per cell (P < 0.0005). Inhalation of ozone also caused an increase in the number of apoptotic cells (P = 0.002). Airway neutrophilia was associated with an increase in MN frequency (P = 0.033) independent of the direct effects of ozone exposure (P < 0.0001). We also observed significant increases in both MN and NB frequencies after exercise in filtered air, suggesting that physical activity is also an important inducer of oxidative stress. These results corroborate our previous findings that cytogenetic damage is associated with ozone exposure, and show that damage is dose-dependent. Further study of ozone-induced cytogenetic damage in airway epithelial cells could provide evidence for the role of oxidative injury in lung carcinogenesis, and help to address the potential public health implications of exposures to oxidant environments. PMID:25451016

Effects of individual and combined toxicity of bisphenol A, dibutyl phthalate and cadmium on oxidative stress and genotoxicity in HepG 2 cells.

PubMed

Li, Xiaohui; Yin, Pinghe; Zhao, Ling

2017-07-01

Bisphenol A, dibutyl phthalate and cadmium can be found in environment simultaneously. Several studies suggested that they had genotoxic effect. In this study, mono-exposure and co-exposure treatments, designed by 3 × 3 full factorial, were established to determine the individual toxicity and binary mixtures' combined effects on the oxidative stress and genotoxicity in HepG 2 cells. The highest oxidative damage was observed in the Cd treatments groups. Compared with control groups, the maximum level of reactive oxygen species and malondialdehyde were ∼1.4 fold and ∼2.22 fold respectively. And a minimum level of superoxide dismutase activity was found with the decrease of 43%. The mechanism that excessive oxidative stress led to the DNA damage was inferred. However, cells treated with BPA showed the worst DNA damage rather than Cd, which may because Cd mainly damages DNA repairing mechanism. For the joint effect, different interactions can be found in different biological endpoints for different combinations since different mechanisms have been clarified in mixture toxicity studies. It is sure that the co-exposure groups enhanced cytotoxicity, oxidative stress and genotoxicity compared to the mono-exposures. Synergistic and additive interactions were considered, which means greater threat to organisms when exposed to multiple estrogenic endocrine disruptors. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Hui; Berlo, Damien van; Shi Tingming

2008-02-15

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 reducesmore » 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-1{beta}) and tumour necrosis factor-alpha (TNF{alpha}). 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.« less

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

PubMed

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.

Kinetics of membrane damage to high (HNA) and low (LNA) nucleic acid bacterial clusters in drinking water by ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate.

PubMed

Ramseier, Maaike K; von Gunten, Urs; Freihofer, Pietro; Hammes, Frederik

2011-01-01

Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of membrane damage of native drinking water bacterial cells. Membrane damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the membrane damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell membranes of high nucleic acid (HNA) content bacteria were damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell membranes have a different chemical constitution. Copyright © 2010 Elsevier Ltd. All rights reserved.

Cancer cells recovering from damage exhibit mitochondrial restructuring and increased aerobic glycolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akakura, Shin; Ostrakhovitch, Elena; Sanokawa-Akakura, Reiko

2014-06-13

Highlights: • Some cancer cells recover from severe damage that causes cell death in majority of cells. • Damage-Recovered (DR) cancer cells show reduced mitochondria, mDNA and mitochondrial enzymes. • DR cells show increased aerobic glycolysis, ATP, cell proliferation, and resistance to damage. • DR cells recovered from in vivo damage also show increased glycolysis and proliferation rate. - Abstract: Instead of relying on mitochondrial oxidative phosphorylation, most cancer cells rely heavily on aerobic glycolysis, a phenomenon termed as “the Warburg effect”. We considered that this effect is a direct consequence of damage which persists in cancer cells that recovermore » from damage. To this end, we studied glycolysis and rate of cell proliferation in cancer cells that recovered from severe damage. We show that in vitro Damage-Recovered (DR) cells exhibit mitochondrial structural remodeling, display Warburg effect, and show increased in vitro and in vivo proliferation and tolerance to damage. To test whether cancer cells derived from tumor microenvironment can show similar properties, we isolated Damage-Recovered (T{sup DR}) cells from tumors. We demonstrate that T{sup DR} cells also show increased aerobic glycolysis and a high proliferation rate. These findings show that Warburg effect and its consequences are induced in cancer cells that survive severe damage.« less

Evaluation of whole cigarette smoke induced oxidative stress in A549 and BEAS-2B cells.

PubMed

Zhang, Shimin; Li, Xiang; Xie, Fuwei; Liu, Kejian; Liu, Huimin; Xie, Jianping

2017-09-01

Cigarette smoke is a complex and oxidative aerosol. Previous researches on the hazards of cigarette smoke mainly focused on the adverse bioeffects induced by its condensates or gas vapor phase, which ignored the dynamic processes of smoking and the cigarette smoke aging. To overcome these disadvantages, we performed air-liquid interface exposure of whole smoke, which used native and unmodified smoke and ensured the exposure similar to physiological inhalation. Our results indicated that whole cigarette smoke induced lung epithelial cells (A549) and bronchial epithelial cells (BEAS-2B) damages in cytotoxicity assays (methyl thiazoly tetrazolium and neutral red uptake assays). In addition, A549 and BEAS-2B cells showed oxidative damages in whole smoke exposure, with concentration change of several biomarkers (reduced and oxidized glutathione, malondialdehyde, 4-hydroxyhydroxy-2-nonenal, extracellular superoxide dismutase, and 8-hydroxyl deoxyguanosine). These results indicate that whole smoke-induced oxidative stress occurs in two different kinds of cells at air-liquid interface. Copyright © 2017 Elsevier B.V. All rights reserved.

Lipids and Oxidative Stress Associated with Ethanol-Induced Neurological Damage

PubMed Central

2016-01-01

The excessive intake of alcohol is a serious public health problem, especially given the severe damage provoked by chronic or prenatal exposure to alcohol that affects many physiological processes, such as memory, motor function, and cognitive abilities. This damage is related to the ethanol oxidation in the brain. The metabolism of ethanol to acetaldehyde and then to acetate is associated with the production of reactive oxygen species that accentuate the oxidative state of cells. This metabolism of ethanol can induce the oxidation of the fatty acids in phospholipids, and the bioactive aldehydes produced are known to be associated with neurotoxicity and neurodegeneration. As such, here we will review the role of lipids in the neuronal damage induced by ethanol-related oxidative stress and the role that lipids play in the related compensatory or defense mechanisms. PMID:26949445

Tankyrase1-mediated poly(ADP-ribosyl)ation of TRF1 maintains cell survival after telomeric DNA damage

PubMed Central

Yang, Lu; Sun, Luxi; Teng, Yaqun; Chen, Hao; Gao, Ying; Levine, Arthur S.; Nakajima, Satoshi

2017-01-01

Abstract Oxidative DNA damage triggers telomere erosion and cellular senescence. However, how repair is initiated at telomeres is largely unknown. Here, we found unlike PARP1-mediated Poly-ADP-Ribosylation (PARylation) at genomic damage sites, PARylation at telomeres is mainly dependent on tankyrase1 (TNKS1). TNKS1 is recruited to damaged telomeres via its interaction with TRF1, which subsequently facilitates the PARylation of TRF1 after damage. TNKS inhibition abolishes the recruitment of the repair proteins XRCC1 and polymerase β at damaged telomeres, while the PARP1/2 inhibitor only has such an effect at non-telomeric damage sites. The ANK domain of TNKS1 is essential for the telomeric damage response and TRF1 interaction. Mutation of the tankyrase-binding motif (TBM) on TRF1 (13R/18G to AA) disrupts its interaction with TNKS1 concomitant recruitment of TNKS1 and repair proteins after damage. Either TNKS1 inhibition or TBM mutated TRF1 expression markedly sensitizes cells to telomere oxidative damage as well as XRCC1 inhibition. Together, our data reveal a novel role of TNKS1 in facilitating SSBR at damaged telomeres through PARylation of TRF1, thereby protecting genome stability and cell viability. PMID:28160604

Omega-3 and omega-6 fatty acids suppress ER- and oxidative stress in cultured neurons and neuronal progenitor cells from mice lacking PPT1.

PubMed

Kim, Sung-Jo; Zhang, Zhongjian; Saha, Arjun; Sarkar, Chinmoy; Zhao, Zhenwen; Xu, Yan; Mukherjee, Anil B

2010-08-02

Reactive oxygen species (ROS) damage brain lipids, carbohydrates, proteins, as well as DNA and may contribute to neurodegeneration. We previously reported that ER- and oxidative stress cause neuronal apoptosis in infantile neuronal ceroid lipofuscinosis (INCL), a lethal neurodegenerative storage disease, caused by palmitoyl-protein thioesterase-1 (PPT1) deficiency. Polyunsaturated fatty acids (PUFA) are essential components of cell membrane phospholipids in the brain and excessive ROS may cause oxidative damage of PUFA leading to neuronal death. Using cultured neurons and neuroprogenitor cells from mice lacking Ppt1, which mimic INCL, we demonstrate that Ppt1-deficient neurons and neuroprogenitor cells contain high levels of ROS, which may cause peroxidation of PUFA and render them incapable of providing protection against oxidative stress. We tested whether treatment of these cells with omega-3 or omega-6 PUFA protects the neurons and neuroprogenitor cells from oxidative stress and suppress apoptosis. We report here that both omega-3 and omega-6 fatty acids protect the Ppt1-deficient cells from ER- as well as oxidative stress and suppress apoptosis. Our results suggest that PUFA supplementation may have neuroprotective effects in INCL. Published by Elsevier Ireland Ltd.

Intracellular Copper Does Not Catalyze the Formation of Oxidative DNA Damage in Escherichia coli▿

PubMed Central

Macomber, Lee; Rensing, Christopher; Imlay, James A.

2007-01-01

Because copper catalyzes the conversion of H2O2 to hydroxyl radicals in vitro, it has been proposed that oxidative DNA damage may be an important component of copper toxicity. Elimination of the copper export genes, copA, cueO, and cusCFBA, rendered Escherichia coli sensitive to growth inhibition by copper and provided forcing circumstances in which this hypothesis could be tested. When the cells were grown in medium supplemented with copper, the intracellular copper content increased 20-fold. However, the copper-loaded mutants were actually less sensitive to killing by H2O2 than cells grown without copper supplementation. The kinetics of cell death showed that excessive intracellular copper eliminated iron-mediated oxidative killing without contributing a copper-mediated component. Measurements of mutagenesis and quantitative PCR analysis confirmed that copper decreased the rate at which H2O2 damaged DNA. Electron paramagnetic resonance (EPR) spin trapping showed that the copper-dependent H2O2 resistance was not caused by inhibition of the Fenton reaction, for copper-supplemented cells exhibited substantial hydroxyl radical formation. However, copper EPR spectroscopy suggested that the majority of H2O2-oxidizable copper is located in the periplasm; therefore, most of the copper-mediated hydroxyl radical formation occurs in this compartment and away from the DNA. Indeed, while E. coli responds to H2O2 stress by inducing iron sequestration proteins, H2O2-stressed cells do not induce proteins that control copper levels. These observations do not explain how copper suppresses iron-mediated damage. However, it is clear that copper does not catalyze significant oxidative DNA damage in vivo; therefore, copper toxicity must occur by a different mechanism. PMID:17189367

Herbal Formulation C168 Attenuates Proliferation and Induces Apoptosis in HCT 116 Human Colorectal Carcinoma Cells: Role of Oxidative Stress and DNA Damage

PubMed Central

Leong, Lek Mun; Chan, Kok Meng; Hamid, Asmah; Latip, Jalifah; Rajab, Nor Fadilah

2016-01-01

The use of herbal formulations has gained scientific interest, particularly in cancer treatment. In this study, the herbal formulation of interest, denoted as C168, is a mixture of eight genera of plants. This study aims to investigate the antiproliferative effect of C168 methanol extract (CME) on various cancer cells and its underlying mechanism of action on the most responsive cell line, namely, HCT 116 cells. CME exerted antiproliferative activities on HCT 116 colorectal carcinoma cells and HepG2 hepatocellular carcinoma cells but not on CCD-841-CoN normal colon epithelial cells, Jurkat E6.1 lymphoblastic leukemic cells, and V79-4 Chinese hamster lung fibroblasts. Further investigation on HCT 116 cells showed that CME induced G2/M cell-cycle arrest and apoptosis. Treatment of CME induced oxidative stress in HCT 116 cells by increasing the superoxide anion level and decreasing the intracellular glutathione. CME also increased tail moment value and H2AX phosphorylation in HCT 116 cells, suggesting DNA damage as an early signal of CME induced apoptosis. Loss of mitochondrial membrane potential in CME-treated cells also indicated the involvement of mitochondria in CME induced apoptosis. This study indicated the selectivity of CME toward colon cancer cells with the involvement of oxidative damage as its possible mechanism of action. PMID:26884792

Effect of oxygen tension on bioenergetics and proteostasis in young and old myoblast precursor cells.

PubMed

Konigsberg, M; Pérez, V I; Ríos, C; Liu, Y; Lee, S; Shi, Y; Van Remmen, H

2013-01-01

In the majority of studies using primary cultures of myoblasts, the cells are maintained at ambient oxygen tension (21% O2), despite the fact that physiological O2 at the tissue level in vivo is much lower (~1-5% O2). We hypothesized that the cellular response in presence of high oxygen concentration might be particularly important in studies comparing energetic function or oxidative stress in cells isolated from young versus old animals. To test this, we asked whether oxygen tension plays a role in mitochondrial bioenergetics (oxygen consumption, glycolysis and fatty acid oxidation) or oxidative damage to proteins (protein disulfides, carbonyls and aggregates) in myoblast precursor cells (MPCs) isolated from young (3-4 m) and old (29-30 m) C57BL/6 mice. MPCs were grown under physiological (3%) or ambient (21%) O2 for two weeks prior to exposure to an acute oxidative insult (H2O2). Our results show significantly higher basal mitochondrial respiration in young versus old MPCs, an increase in basal respiration in young MPCs maintained at 3% O2 compared to cells maintained at 21% O2, and a shift toward glycolytic metabolism in old MPCs grown at 21% O2. H2O2 treatment significantly reduced respiration in old MPCs grown at 3% O2 but did not further repress respiration at 21% O2 in old MPCs. Oxidative damage to protein was higher in cells maintained at 21% O2 and increased in response to H2O2 in old MPCs. These data underscore the importance of understanding the effect of ambient oxygen tension in cell culture studies, in particular studies measuring oxidative damage and mitochondrial function.

Nickel-Refining Fumes Induced DNA Damage and Apoptosis of NIH/3T3 Cells via Oxidative Stress

PubMed Central

Wang, Yue; Wang, Sheng-Yuan; Jia, Li; Zhang, Lin; Ba, Jing-Chong; Han, Dan; Yu, Cui-Ping; Wu, Yong-Hui

2016-01-01

Although there have been numerous studies examining the toxicity and carcinogenicity of nickel compounds in humans and animals, its molecular mechanisms of action are not fully elucidated. In our research, NIH/3T3 cells were exposed to nickel-refining fumes at the concentrations of 0, 6.25, 12.50, 25, 50 and 100 μg/mL for 24 h. Cell viability, cell apoptosis, reactive oxygen species (ROS) level, lactate dehydrogenase (LDH) assay, the level of glutathione (GSH), activities of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) level were detected. The exposure of NIH/3T3 cells to nickel-refining fumes significantly reduced cell viability and induced cell apoptotic death in a dose-dependent manner. Nickel-refining fumes significantly increased ROS levels and induced DNA damage. Nickel-refining fumes may induce the changes in the state of ROS, which may eventually initiate oxidative stress, DNA damage and apoptosis of NIH/3T3 cells. PMID:27347984

The endoperoxide ascaridol shows strong differential cytotoxicity in nucleotide excision repair-deficient cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbasi, Rashda; Efferth, Thomas; Kuhmann, Christine

2012-03-15

Targeting synthetic lethality in DNA repair pathways has become a promising anti-cancer strategy. However little is known about such interactions with regard to the nucleotide excision repair (NER) pathway. Therefore, cell lines with a defect in the NER genes ERCC6 or XPC and their normal counterparts were screened with 53 chemically defined phytochemicals isolated from plants used in traditional Chinese medicine for differential cytotoxic effects. The screening revealed 12 drugs that killed NER-deficient cells more efficiently than proficient cells. Five drugs were further analyzed for IC{sub 50} values, effects on cell cycle distribution, and induction of DNA damage. Ascaridol wasmore » the most effective compound with a difference of > 1000-fold in resistance between normal and NER-deficient cells (IC{sub 50} values for cells with deficiency in ERCC6: 0.15 μM, XPC: 0.18 μM, and normal cells: > 180 μM). NER-deficiency combined with ascaridol treatment led to G2/M-phase arrest, an increased percentage of subG1 cells, and a substantially higher DNA damage induction. These results were confirmed in a second set of NER-deficient and -proficient cell lines with isogenic background. Finally, ascaridol was characterized for its ability to generate oxidative DNA damage. The drug led to a dose-dependent increase in intracellular levels of reactive oxygen species at cytotoxic concentrations, but only NER-deficient cells showed a strongly induced amount of 8-oxodG sites. In summary, ascaridol is a cytotoxic and DNA-damaging compound which generates intracellular reactive oxidative intermediates and which selectively affects NER-deficient cells. This could provide a new therapeutic option to treat cancer cells with mutations in NER genes. -- Highlights: ► Thousand-fold higher Ascaridol activity in NER-deficient versus proficient cells. ► Impaired repair of Ascaridol-induced oxidative DNA damage in NER-deficient cells. ► Selective activity of Ascaridol opens new therapy options in NER-deficient tumors.« less

Induction and repair of DNA damage measured by the comet assay in human T lymphocytes separated by immunomagnetic cell sorting.

PubMed

Bausinger, Julia; Speit, Günter

2014-11-01

The comet assay is widely used in human biomonitoring to measure DNA damage in whole blood or isolated peripheral blood mononuclear cells (PBMC) as a marker of exposure to genotoxic agents. Cytogenetic assays with phytohemagglutinin (PHA)-stimulated cultured T lymphocytes are also frequently performed in human biomonitoring. Cytogenetic effects (micronuclei, chromosome aberrations, sister chromatid exchanges) may be induced in vivo but also occur ex vivo during the cultivation of lymphocytes as a consequence of DNA damage present in lymphocytes at the time of sampling. To better understand whether DNA damage measured by the comet assay in PBMC is representative for DNA damage in T cells, we comparatively investigated DNA damage and its repair in PBMC and T cells obtained by immunomagnetic cell sorting. PBMC cultures and T cell cultures were exposed to mutagens with different modes of genotoxic action and DNA damage was measured by the comet assay after the end of a 2h exposure and after 18h post-incubation. The mutagens tested were methyl methanesulfonate (MMS), (±)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), 4-nitroquinoline-1-oxide (4NQO), styrene oxide and potassium bromate. MMS and potassium bromate were also tested by the modified comet assay with formamido pyrimidine glycosylase (FPG) protein. The results indicate that the mutagens tested induce DNA damage in PBMC and T cells in the same range of concentrations and removal of induced DNA lesions occurs to a comparable extent. Based on these results, we conclude that the comet assay with PBMC is suited to predict DNA damage and its removal in T cells. Copyright © 2014 Elsevier B.V. All rights reserved.

Oxidative stress contributes to the tamoxifen-induced killing of breast cancer cells: implications for tamoxifen therapy and resistance

PubMed Central

Bekele, Raie T.; Venkatraman, Ganesh; Liu, Rong-Zong; Tang, Xiaoyun; Mi, Si; Benesch, Matthew G. K.; Mackey, John R.; Godbout, Roseline; Curtis, Jonathan M.; McMullen, Todd P. W.; Brindley, David N.

2016-01-01

Tamoxifen is the accepted therapy for patients with estrogen receptor-α (ERα)-positive breast cancer. However, clinical resistance to tamoxifen, as demonstrated by recurrence or progression on therapy, is frequent and precedes death from metastases. To improve breast cancer treatment it is vital to understand the mechanisms that result in tamoxifen resistance. This study shows that concentrations of tamoxifen and its metabolites, which accumulate in tumors of patients, killed both ERα-positive and ERα-negative breast cancer cells. This depended on oxidative damage and anti-oxidants rescued the cancer cells from tamoxifen-induced apoptosis. Breast cancer cells responded to tamoxifen-induced oxidation by increasing Nrf2 expression and subsequent activation of the anti-oxidant response element (ARE). This increased the transcription of anti-oxidant genes and multidrug resistance transporters. As a result, breast cancer cells are able to destroy or export toxic oxidation products leading to increased survival from tamoxifen-induced oxidative damage. These responses in cancer cells also occur in breast tumors of tamoxifen-treated mice. Additionally, high levels of expression of Nrf2, ABCC1, ABCC3 plus NAD(P)H dehydrogenase quinone-1 in breast tumors of patients at the time of diagnosis were prognostic of poor survival after tamoxifen therapy. Therefore, overcoming tamoxifen-induced activation of the ARE could increase the efficacy of tamoxifen in treating breast cancer. PMID:26883574

Menadione-Induced DNA Damage Leads to Mitochondrial Dysfunction and Fragmentation During Rosette Formation in Fuchs Endothelial Corneal Dystrophy

PubMed Central

Halilovic, Adna; Schmedt, Thore; Benischke, Anne-Sophie; Hamill, Cecily; Chen, Yuming; Santos, Janine Hertzog

2016-01-01

Abstract Aims: 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. Results: 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. Innovation: 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. Conclusion: 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. PMID:26935406

Menadione-Induced DNA Damage Leads to Mitochondrial Dysfunction and Fragmentation During Rosette Formation in Fuchs Endothelial Corneal Dystrophy.

PubMed

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.

Hydroxytyrosol Protects against Oxidative DNA Damage in Human Breast Cells

PubMed Central

Warleta, Fernando; Quesada, Cristina Sánchez; Campos, María; Allouche, Yosra; Beltrán, Gabriel; Gaforio, José J.

2011-01-01

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. PMID:22254082

[The correlations between aging of the human body, oxidative stress and reduced efficiency of repair systems].

PubMed

Michalak, Aleksandra; Krzeszowiak, Jakub; Markiewicz-Górka, Iwona

2014-12-15

The article presents an current knowledge overview about the importance of oxidative stress and reduced efficiency of repair processes during the aging process of the human body. Oxidative damage to cellular macromolecules (proteins, lipids, nucleic acids), are formed under the influence of reactive oxygen species (ROS). They are the part of important mechanism which is responsible for the process of aging and the development of many diseases. The most important effects result from DNA damage, due to the mutations formation, which can lead to the development of tumors. However, a well-functioning repair systems (i.a. homologous recombination) remove the damage and prevent harmful changes in the cells. Lipid peroxidation products also cause oxidative modification of nucleic acids (and proteins). Proteins and fats also have repair systems, but much simpler than those responsible for the repair of nucleic acids. Unfortunately, with increasing age, they are more weakened, which contributes to increase numbers of cell damage, and consequently development of diseases specific to old age: cancer, neurodegenerative diseases or atherosclerosis.

Melittin induced cytogenetic damage, oxidative stress and changes in gene expression in human peripheral blood lymphocytes.

PubMed

Gajski, Goran; Domijan, Ana-Marija; Žegura, Bojana; Štern, Alja; Gerić, Marko; Novak Jovanović, Ivana; Vrhovac, Ivana; Madunić, Josip; Breljak, Davorka; Filipič, Metka; Garaj-Vrhovac, Vera

2016-02-01

Melittin (MEL) is the main constituent and principal toxin of bee venom. It is a small basic peptide, consisting of a known amino acid sequence, with powerful haemolytic activity. Since MEL is a nonspecific cytolytic peptide that attacks lipid membranes thus leading to toxicity, the presumption is that it could have significant therapeutic benefits. The aim was to evaluate the cyto/genotoxic effects of MEL in human peripheral blood lymphocytes (HPBLs) and the molecular mechanisms involved using a multi-biomarker approach. We found that MEL was cytotoxic for HPBLs in a dose- and time-dependent manner. It also induced morphological changes in the cell membrane, granulation and lysis of exposed cells. After treating HPBLs with non-cytotoxic concentrations of MEL, we observed increased DNA damage including oxidative DNA damage as well as increased formation of micronuclei and nuclear buds, and decreased lymphocyte proliferation determined by comet and micronucleus assays. The observed genotoxicity coincided with increased formation of reactive oxygen species, reduction of glutathione level, increased lipid peroxidation and phospholipase C activity, showing the induction of oxidative stress. MEL also modulated the expression of selected genes involved in DNA damage response (TP53, CDKN1A, GADD45α, MDM), oxidative stress (CAT, SOD1, GPX1, GSR and GCLC) and apoptosis (BAX, BCL-2, CAS-3 and CAS-7). Results indicate that MEL is genotoxic to HPBLs and provide evidence that oxidative stress is involved in its DNA damaging effects. MEL toxicity towards normal cells has to be considered if used for potential therapeutic purposes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mitochondrial dependent oxidative stress in cell culture induced by laser radiation at 1265 nm.

PubMed

Saenko, Yury V; Glushchenko, Eugenia S; Zolotovskii, Igor O; Sholokhov, Evgeny; Kurkov, Andrey

2016-04-01

Photodynamic therapy is the main technique applied for surface carcinoma treatment. This technique employs singlet oxygen generated via a laser excited photosensitizer as a main damaging agent. However, prolonged sensitivity to intensive light, relatively low tissue penetration by activating light the cost of photosensitizer (PS) administration can limit photodynamic therapy applications. Early was reported singlet oxygen generation without photosensitizer induced by a laser irradiation at the wavelength of 1250-1270 nm. Here, we study the dynamics of oxidative stress, DNA damage, changes of mitochondrial potential, and mitochondrial mass induced by a laser at 1265 nm have been studied in HCT-116 and CHO-K cells. Laser irradiation of HCT-116 and CHO-K cells has induced a dose-dependent cell death via increasing intracellular reactive oxygen species (ROS) concentration, increase of DNA damage, decrease of mitochondrial potential, and reduced glutathione. It has been shown that, along with singlet oxygen generation, the increase of the intracellular ROS concentration induced by mitochondrial damage contributes to the damaging effect of the laser irradiation at 1265 nm.

Sargassum horneri methanol extract rescues C2C12 murine skeletal muscle cells from oxidative stress-induced cytotoxicity through Nrf2-mediated upregulation of heme oxygenase-1.

PubMed

Kang, Ji Sook; Choi, Il-Whan; Han, Min Ho; Hong, Su Hyun; Kim, Sung Ok; Kim, Gi-Young; Hwang, Hye Jin; Kim, Byung Woo; Choi, Byung Tae; Kim, Cheol Min; Choi, Yung Hyun

2015-02-05

Sargassum horneri, an edible marine brown alga, is typically distributed along the coastal seas of Korea and Japan. Although several studies have demonstrated the anti-oxidative activity of this alga, the regulatory mechanisms have not yet been defined. The aim of the present study was to examine the cytoprotective effects of S. horneri against oxidative stress-induced cell damage in C2C12 myoblasts. We demonstrated the anti-oxidative effects of a methanol extract of S. horneri (SHME) in a hydrogen peroxide (H2O2)-stimulated C2C12 myoblast model. Cytotoxicity was determined using the 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyl-tetrazolium assay and mode of cell death by cell cycle analysis. DNA damage was measured using a comet assay and expression of phospho-histone γH2A.X (p-γH2A.X). Levels of cellular oxidative stress as reactive oxygen species (ROS) accumulation were measured using 2',7'-dichlorofluorescein diacetate. The involvement of selected genes in the oxidative stress-mediated signaling pathway was explored using Western blot analysis. SHME attenuated H2O2-induced growth inhibition and exhibited scavenging activity against intracellular ROS that were induced by H2O2. The SHME also inhibited comet tail formation, p-γH2A.X expression, and the number of sub-G1 hypodiploid cells, suggesting that it prevents H2O2-induced cellular DNA damage and apoptotic cell death. Furthermore, the SHME significantly enhanced the expression of heme oxygenase-1 (HO-1) associated with induction of nuclear factor-erythroid 2 related factor 2 (Nrf2) in a time- and concentration-dependent manner. Moreover, the protective effect of the SHME on H2O2-induced C2C12 cell damage was significantly abolished by zinc protoporphyrin IX, a HO-1 competitive inhibitor, in C2C12 cells. These findings suggest that the SHME augments cellular antioxidant defense capacity through both intrinsic free radical scavenging activity and activation of the Nrf2/HO-1 pathway, protecting C2C12 cells from H2O2-induced oxidative cytotoxicity.

Metallothionein blocks oxidative DNA damage induced by acute inorganic arsenic exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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% andmore » 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.« less

Replicative stress and alterations in cell cycle checkpoint controls following acetaminophen hepatotoxicity restrict liver regeneration.

PubMed

Viswanathan, Preeti; Sharma, Yogeshwar; Gupta, Priya; Gupta, Sanjeev

2018-03-05

Acetaminophen hepatotoxicity is a leading cause of hepatic failure with impairments in liver regeneration producing significant mortality. Multiple intracellular events, including oxidative stress, mitochondrial damage, inflammation, etc., signify acetaminophen toxicity, although how these may alter cell cycle controls has been unknown and was studied for its significance in liver regeneration. Assays were performed in HuH-7 human hepatocellular carcinoma cells, primary human hepatocytes and tissue samples from people with acetaminophen-induced acute liver failure. Cellular oxidative stress, DNA damage and cell proliferation events were investigated by mitochondrial membrane potential assays, flow cytometry, fluorescence staining, comet assays and spotted arrays for protein expression after acetaminophen exposures. In experimental groups with acetaminophen toxicity, impaired mitochondrial viability and substantial DNA damage were observed with rapid loss of cells in S and G2/M and cell cycle restrictions or even exit in the remainder. This resulted from altered expression of the DNA damage regulator, ATM and downstream transducers, which imposed G1/S checkpoint arrest, delayed entry into S and restricted G2 transit. Tissues from people with acute liver failure confirmed hepatic DNA damage and cell cycle-related lesions, including restrictions of hepatocytes in aneuploid states. Remarkably, treatment of cells with a cytoprotective cytokine reversed acetaminophen-induced restrictions to restore cycling. Cell cycle lesions following mitochondrial and DNA damage led to failure of hepatic regeneration in acetaminophen toxicity but their reversibility offers molecular targets for treating acute liver failure. © 2018 John Wiley & Sons Ltd.

Heat shock proteins and proteasomal degradation in normal and tumor cells.

PubMed

Karademir, Betul; Bozaykut, Perinur; Kartal Ozer, Nesrin

2014-10-01

Proteasomal degradation of oxidized proteins is a crucial mechanism to prevent the accumulation of cellular damage. The removal of the damage is generally a required process for healthy organisms to keep the integrity while in cancer cells the situation may be different. In normal conditions, cancer cells have higher proteasome activity compared to normal cells. During cancer treatment, cellular damage by chemotherapy is an expected process to be able to kill the tumor cells. And the accumulation of this damage accompanied by the decrease in protein repair and removal systems may increase the efficacy of the cancer therapy. Heat shock proteins (Hsp) as molecular chaperones are involved in the folding, activation and assembly of a variety of proteins. Among these Hsp40, Hsp70 and Hsp90 are believed to act as a chaperone system to regulate the proteasomal degradation. In this study, we tested the role of heat stress response on the proteasomal degradation of oxidized proteins. We used two different cell lines to observe the difference in normal and tumor cells. First the effect of heat stress (42°C, 1h) were tested in terms of protein oxidation tested by protein carbonyl formation and proteasomal degradation. The results were extremely different in normal fibroblast cells and hippocampal tumor cells. In the same direction, the expressions of Hsp40, Hsp70 and Hsp90 were affected in a different manner in two cell lines, will be discussed in detail. Supported by TUBITAK COST-CM1001-110S281. Copyright © 2014. Published by Elsevier Inc.

Chronic Oxidative Damage together with Genome Repair Deficiency in the Neurons is a Double Whammy for Neurodegeneration: Is Damage Response Signaling a Potential Therapeutic Target?

PubMed Central

Wang, Haibo; Dharmalingam, Prakash; Vasquez, Velmarini; Mitra, Joy; Boldogh, Istvan; Rao, K. S.; Kent, Thomas A.; Mitra, Sankar; Hegde, Muralidhar L.

2016-01-01

A foremost challenge for the neurons, which are among the most oxygenated cells, is the genome damage caused by chronic exposure to endogenous reactive oxygen species (ROS), formed as cellular respiratory byproducts. Strong metabolic activity associated with high transcriptional levels in these long lived post-mitotic cells render them vulnerable to oxidative genome damage, including DNA strand breaks and mutagenic base lesions. There is growing evidence for the accumulation of unrepaired DNA lesions in the central nervous system (CNS) during accelerated ageing and progressive neurodegeneration. Several germ line mutations in DNA repair or DNA damage response (DDR) signaling genes are uniquely manifested in the phenotype of neuronal dysfunction and are etiologically linked to many neurodegenerative disorders. Studies in our lab and elsewhere revealed that pro-oxidant metals, ROS and misfolded amyloidogenic proteins not only contribute to genome damage in CNS, but also impede their repair/DDR signaling leading to persistent damage accumulation, a common feature in sporadic neurodegeneration. Here, we have reviewed recent advances in our understanding of the etiological implications of DNA damage vs. repair imbalance, abnormal DDR signaling in triggering neurodegeneration and potential of DDR as a target for the amelioration of neurodegenerative diseases. PMID:27663141

Doxorubicin-induced necrosis is mediated by poly-(ADP-ribose) polymerase 1 (PARP1) but is independent of p53.

PubMed

Shin, Hyeon-Jun; Kwon, Hyuk-Kwon; Lee, Jae-Hyeok; Gui, Xiangai; Achek, Asma; Kim, Jae-Ho; Choi, Sangdun

2015-11-02

Necrosis, unregulated cell death, is characterized by plasma membrane rupture as well as nuclear and cellular swelling. However, it has recently been reported that necrosis is a regulated form of cell death mediated by poly-(ADP-ribose) polymerase 1 (PARP1). PARP1 is thought to mediate necrosis by inducing DNA damage, although this remains unconfirmed. In this study, we examined the mechanisms of PARP1-mediated necrosis following doxorubicin (DOX)-induced DNA damage in human kidney proximal tubular (HK-2) cells. DOX initiated DNA damage response (DDR) and upregulated PARP1 and p53 expression, resulting in morphological changes similar to those observed during necrosis. Additionally, DOX induced mitochondrial hyper-activation, as evidenced by increased mitochondrial respiration and cytosolic ATP (cATP) production. However, DOX affected mitochondrial mass. DOX-induced DNA damage, cytosolic reactive oxygen species (cROS) generation, and mitochondrial hyper-activation decreased in cells with inhibited PARP1 expression, while generation of nitric oxide (NO) and mitochondrial ROS (mROS) remained unaffected. Moreover, DOX-induced DNA damage, cell cycle changes, and oxidative stress were not affected by p53 inhibition. These findings suggest that DNA damage induced necrosis through a PARP1-dependent and p53-independent pathway.

Doxorubicin-induced necrosis is mediated by poly-(ADP-ribose) polymerase 1 (PARP1) but is independent of p53

PubMed Central

Shin, Hyeon-Jun; Kwon, Hyuk-Kwon; Lee, Jae-Hyeok; Gui, Xiangai; Achek, Asma; Kim, Jae-Ho; Choi, Sangdun

2015-01-01

Necrosis, unregulated cell death, is characterized by plasma membrane rupture as well as nuclear and cellular swelling. However, it has recently been reported that necrosis is a regulated form of cell death mediated by poly-(ADP-ribose) polymerase 1 (PARP1). PARP1 is thought to mediate necrosis by inducing DNA damage, although this remains unconfirmed. In this study, we examined the mechanisms of PARP1-mediated necrosis following doxorubicin (DOX)-induced DNA damage in human kidney proximal tubular (HK-2) cells. DOX initiated DNA damage response (DDR) and upregulated PARP1 and p53 expression, resulting in morphological changes similar to those observed during necrosis. Additionally, DOX induced mitochondrial hyper-activation, as evidenced by increased mitochondrial respiration and cytosolic ATP (cATP) production. However, DOX affected mitochondrial mass. DOX-induced DNA damage, cytosolic reactive oxygen species (cROS) generation, and mitochondrial hyper-activation decreased in cells with inhibited PARP1 expression, while generation of nitric oxide (NO) and mitochondrial ROS (mROS) remained unaffected. Moreover, DOX-induced DNA damage, cell cycle changes, and oxidative stress were not affected by p53 inhibition. These findings suggest that DNA damage induced necrosis through a PARP1-dependent and p53-independent pathway. PMID:26522181

Flavonoid Fraction of Orange and Bergamot Juices Protect Human Lung Epithelial Cells from Hydrogen Peroxide-Induced Oxidative Stress

PubMed Central

Ferlazzo, Nadia; Visalli, Giuseppa; Smeriglio, Antonella; Cirmi, Santa; Lombardo, Giovanni Enrico; Campiglia, Pietro; Di Pietro, Angela

2015-01-01

It has been reported that oxidant/antioxidant imbalance triggers cell damage that in turn causes a number of lung diseases. Flavonoids are known for their health benefits, and Citrus fruits juices are one of the main food sources of these secondary plant metabolites. The present study was designed to evaluate the effect of the flavonoid fraction of bergamot and orange juices, on H2O2-induced oxidative stress in human lung epithelial A549 cells. First we tested the antioxidant properties of both extracts in cell-free experimental models and then we assayed their capability to prevent the cytotoxic effects induced by H2O2. Our results demonstrated that both Citrus juice extracts reduce the generation of reactive oxygen species and membrane lipid peroxidation, improve mitochondrial functionality, and prevent DNA-oxidative damage in A549 cells incubated with H2O2. Our data indicate that the mix of flavonoids present in both bergamot and orange juices may be of use in preventing oxidative cell injury and pave the way for further research into a novel healthy approach to avoid lung disorders. PMID:26221182

Flavonoid Fraction of Orange and Bergamot Juices Protect Human Lung Epithelial Cells from Hydrogen Peroxide-Induced Oxidative Stress.

PubMed

Ferlazzo, Nadia; Visalli, Giuseppa; Smeriglio, Antonella; Cirmi, Santa; Lombardo, Giovanni Enrico; Campiglia, Pietro; Di Pietro, Angela; Navarra, Michele

2015-01-01

It has been reported that oxidant/antioxidant imbalance triggers cell damage that in turn causes a number of lung diseases. Flavonoids are known for their health benefits, and Citrus fruits juices are one of the main food sources of these secondary plant metabolites. The present study was designed to evaluate the effect of the flavonoid fraction of bergamot and orange juices, on H2O2-induced oxidative stress in human lung epithelial A549 cells. First we tested the antioxidant properties of both extracts in cell-free experimental models and then we assayed their capability to prevent the cytotoxic effects induced by H2O2. Our results demonstrated that both Citrus juice extracts reduce the generation of reactive oxygen species and membrane lipid peroxidation, improve mitochondrial functionality, and prevent DNA-oxidative damage in A549 cells incubated with H2O2. Our data indicate that the mix of flavonoids present in both bergamot and orange juices may be of use in preventing oxidative cell injury and pave the way for further research into a novel healthy approach to avoid lung disorders.

Protection by sulforaphane from type 1 diabetes-induced testicular apoptosis is associated with the up-regulation of Nrf2 expression and function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Xin; Bai, Yang; Zhang, Zhiguo

Diabetes-induced testicular apoptosis is predominantly due to increased oxidative stress. The nuclear factor-erythroid 2-related factor 2 (Nrf2), as a master transcription factor in controlling anti-oxidative systems, is able to be induced by sulforaphane (SFN). To examine whether SFN prevents testicular apoptosis, type 1 diabetic mouse model was induced with multiple low-dose streptozotocin. Diabetic and age-matched control mice were treated with and without SFN at 0.5 mg/kg daily in five days of each week for 3 months and then kept until 6 months. Diabetes significantly increased testicular apoptosis that was associated with endoplasmic reticulum stress and mitochondrial cell death pathways, shownmore » by the increased expression of C/EBP homologous protein (CHOP), cleaved caspase-12, Bax to Bcl2 expression ratio, and cleaved caspase-3. Diabetes also significantly increased testicular oxidative damage, inflammation and fibrosis, and decreased germ cell proliferation. All these diabetic effects were significantly prevented by SFN treatment for the first 3 months, and the protective effect could be sustained at 3 months after SFN treatment. SFN was able to up-regulate Nrf2 expression and function. The latter was reflected by the increased phosphorylation of Nrf2 at Ser40 and expression of Nrf2 downstream antioxidants at mRNA and protein levels. These results suggest that type 1 diabetes significantly induced testicular apoptosis and damage along with increasing oxidative stress and cell death and suppressing Nrf2 expression and function. SFN is able to prevent testicular oxidative damage and apoptosis in type 1 diabetes mice, which may be associated with the preservation of testicular Nrf2 expression and function under diabetic condition. - Highlights: • Sulforaphane (SFN) could attenuate diabetes-induced germ cell apoptosis. • SFN could preserve germ cell proliferation under diabetic conditions. • SFN testicular protection was sustained until 3 months after administration. • SFN prevents testicular oxidative damage and inflammation in diabetic mice. • SFN testicular protection from diabetic damage is associated with Nrf2 activation.« less

Hydrocaffeic and p-coumaric acids, natural phenolic compounds, inhibit UV-B damage in WKD human conjunctival cells in vitro and rabbit eye in vivo.

PubMed

Larrosa, Mar; Lodovici, Maura; Morbidelli, Lucia; Dolara, Piero

2008-10-01

This paper studied the effect on UV-B ocular damage of 10microM hydrocaffeic acid (HCAF) alone and as a mixture (MIX) (5 microM HCAF+5 microM p-coumaric acid). Since ocular UV-B damage is mediated by reactive oxygen species, the aim was to test if HCAF and MIX could reduce oxidation damage in human conjunctival cells (WKD) in vitro and in cornea and sclera of rabbits in vivo. After UVB irradiation (44 J/m(2)) of WKD cells, 8-oxodG levels in DNA were markedly increased and this effect was attenuated by HCAF and MIX. Rabbit eyes were treated by application of HCAF and MIX drops before UV-B exposure (79 J/m(2)). Corneal and scleral DNA oxidation damage, xanthine-oxidase (XO) activity and malondialdehyde levels (MDA) in corneal tissue and prostaglandin E(2) (PGE(2)) in the aqueous humour were reduced by HCAF alone and in combination with p-coumaric acid, showing their potential as a topical treatment against UV-B damage.

Reactive oxygen-mediated damage to a human DNA replication and repair protein.

PubMed

Montaner, Beatriz; O'Donovan, Peter; Reelfs, Olivier; Perrett, Conal M; Zhang, Xiaohong; Xu, Yao-Zhong; Ren, Xiaolin; Macpherson, Peter; Frith, David; Karran, Peter

2007-11-01

Ultraviolet A (UVA) makes up more than 90% of incident terrestrial ultraviolet radiation. Unlike shorter wavelength UVB, which damages DNA directly, UVA is absorbed poorly by DNA and is therefore considered to be less hazardous. Organ transplant patients treated with the immunosuppressant azathioprine frequently develop skin cancer. Their DNA contains 6-thioguanine-a base analogue that generates DNA-damaging singlet oxygen ((1)O(2)) when exposed to UVA. Here, we show that this (1)O(2) damages proliferating cell nuclear antigen (PCNA), the homotrimeric DNA polymerase sliding clamp. It causes covalent oxidative crosslinking between the PCNA subunits through a histidine residue in the intersubunit domain. Crosslinking also occurs after treatment with higher-although still moderate-doses of UVA alone or with chemical oxidants. Chronic accumulation of oxidized proteins is linked to neurodegenerative disorders and ageing. Our findings identify oxidative damage to an important DNA replication and repair protein as a previously unrecognized hazard of acute oxidative stress.

Oxidative stress in the pathology and treatment of systemic lupus erythematosus.

PubMed

Perl, Andras

2013-11-01

Oxidative stress is increased in systemic lupus erythematosus (SLE), and it contributes to immune system dysregulation, abnormal activation and processing of cell-death signals, autoantibody production and fatal comorbidities. Mitochondrial dysfunction in T cells promotes the release of highly diffusible inflammatory lipid hydroperoxides, which spread oxidative stress to other intracellular organelles and through the bloodstream. Oxidative modification of self antigens triggers autoimmunity, and the degree of such modification of serum proteins shows striking correlation with disease activity and organ damage in SLE. In T cells from patients with SLE and animal models of the disease, glutathione, the main intracellular antioxidant, is depleted and serine/threonine-protein kinase mTOR undergoes redox-dependent activation. In turn, reversal of glutathione depletion by application of its amino acid precursor, N-acetylcysteine, improves disease activity in lupus-prone mice; pilot studies in patients with SLE have yielded positive results that warrant further research. Blocking mTOR activation in T cells could conceivably provide a well-tolerated and inexpensive alternative approach to B-cell blockade and traditional immunosuppressive treatments. Nevertheless, compartmentalized oxidative stress in self-reactive T cells, B cells and phagocytic cells might serve to limit autoimmunity and its inhibition could be detrimental. Antioxidant therapy might also be useful in ameliorating damage caused by other treatments. This Review thus seeks to critically evaluate the complexity of oxidative stress and its relevance to the pathogenesis and treatment of SLE.

Dexamethasone attenuates oxidation of extracellular matrix proteins by human monocytes.

PubMed

Ahmed, Shahid; Adamidis, Ananea; Jan, Louis C; Gibbons, Nora; Mattana, Joseph

2003-10-01

In response to infection or in immune complex-mediated diseases, inflammatory cells may oxidatively damage extracellular matrix (ECM) proteins. In this study we evaluated whether human monocytes could oxidize ECM and whether this could be modulated by exposure to LPS, IgG complexes, and dexamethasone (DEX). Wells in tissue culture plates were coated with the ECM preparation Matrigel. Porous inserts with or without the human monocyte cell line THP-1 were placed into ECM-containing wells and cells were exposed to control conditions or to LPS (10 ng/ml), IgG complexes (200 and 500 microg/ml), or DEX (10(-7) and 10(-6) M). ECM was then subjected to Western blot analysis using an antibody to oxidized protein. In addition, Western blot analysis was carried out on DEX-treated cells to evaluate expression of the NADPH oxidase components p67-phox and gp91-phox. THP-1 cells enhanced ECM oxidation and this effect was augmented by LPS and by IgG aggregates. Preincubation of cells with DEX attenuated ECM oxidation and was also associated with decreased expression of p67-phox and gp91-phox. These findings suggest that human monocytes can oxidize ECM proteins and that this may be modulated by IgG complexes and LPS. Dexamethasone appears to attenuate ECM oxidation and a better understanding of this mechanism might allow for interventions to minimize oxidative damage to ECM proteins by monocytes in infectious and inflammatory states.

11th International Conference of Radiation Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1999-07-18

Topics discussed in the conference included the following: Radiation Physics, Radiation Chemistry and modelling--Radiation physics and dosimetry; Electron transfer in biological media; Radiation chemistry; Biophysical and biochemical modelling; Mechanisms of DNA damage; Assays of DNA damage; Energy deposition in micro volumes; Photo-effects; Special techniques and technologies; Oxidative damage. Molecular and cellular effects-- Photobiology; Cell cycle effects; DNA damage: Strand breaks; DNA damage: Bases; DNA damage Non-targeted; DNA damage: other; Chromosome aberrations: clonal; Chromosomal aberrations: non-clonal; Interactions: Heat/Radiation/Drugs; Biochemical effects; Protein expression; Gene induction; Co-operative effects; ``Bystander'' effects; Oxidative stress effects; Recovery from radiation damage. DNA damage and repair -- DNAmore » repair genes; DNA repair deficient diseases; DNA repair enzymology; Epigenetic effects on repair; and Ataxia and ATM.« less

Exposure to nano-size titanium dioxide causes oxidative damages in human mesothelial cells: The crystal form rather than size of particle contributes to cytotoxicity.

PubMed

Hattori, Kenji; Nakadate, Kazuhiko; Morii, Akane; Noguchi, Takumi; Ogasawara, Yuki; Ishii, Kazuyuki

2017-10-14

Exposure to nanoparticles such as carbon nanotubes has been shown to cause pleural mesothelioma similar to that caused by asbestos, and has become an environmental health issue. Not only is the percutaneous absorption of nano-size titanium dioxide particles frequently considered problematic, but the possibility of absorption into the body through the pulmonary route is also a concern. Nevertheless, there are few reports of nano-size titanium dioxide particles on respiratory organ exposure and dynamics or on the mechanism of toxicity. In this study, we focused on the morphology as well as the size of titanium dioxide particles. In comparing the effects between nano-size anatase and rutile titanium dioxide on human-derived pleural mesothelial cells, the anatase form was shown to be actively absorbed into cells, producing reactive oxygen species and causing oxidative damage to DNA. In contrast, we showed for the first time that the rutile form is not easily absorbed by cells and, therefore, does not cause oxidative DNA damage and is significantly less damaging to cells. These results suggest that with respect to the toxicity of titanium dioxide particles on human-derived mesothelial cells, the crystal form rather than the particle size has a greater effect on cellular absorption. Also, it was indicated that the difference in absorption is the primary cause of the difference in the toxicity against mesothelial cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Antioxidants and the Integrity of Ocular Tissues

PubMed Central

Cabrera, Marcela P.; Chihuailaf, Ricardo H.

2011-01-01

Oxygen-derived free radicals are normally generated in many pathways. These radicals can interact with various cellular components and induce cell injury. When free radicals exceed the antioxidant capacity, cell injury causes diverse pathologic changes in the organs. The imbalance between the generation of free radicals and antioxidant defence is known as oxidative stress. The eye can suffer the effect of oxidative damage due to the etiopathogenesis of some pathological changes related to oxidative stress. This paper reviews the role of oxidative stress in the onset and progression of damage in different eye structures, the involvement of the antioxidant network in protecting and maintaining the homeostasis of this organ, and the potential assessment methodologies used in research and in some cases in clinical practice. PMID:21789267

Size-dependent cytotoxicity of yttrium oxide nanoparticles on primary osteoblasts in vitro

NASA Astrophysics Data System (ADS)

Zhou, Guoqiang; Li, Yunfei; Ma, Yanyan; Liu, Zhu; Cao, Lili; Wang, Da; Liu, Sudan; Xu, Wenshi; Wang, Wenying

2016-05-01

Yttrium oxide nanoparticles are an excellent host material for the rare earth metals and have high luminescence efficiency providing a potential application in photodynamic therapy and biological imaging. In this study, the effects of yttrium oxide nanoparticles with four different sizes were investigated using primary osteoblasts in vitro. The results demonstrated that the cytotoxicity generated by yttrium oxide nanoparticles depended on the particle size, and smaller particles possessed higher toxicological effects. For the purpose to elucidate the relationship between reactive oxygen species generation and cell damage, cytomembrane integrity, intracellular reactive oxygen species level, mitochondrial membrane potential, cell apoptosis rate, and activity of caspase-3 in cells were then measured. Increased reactive oxygen species level was also observed in a size-dependent way. Thus, our data demonstrated that exposure to yttrium oxide nanoparticles resulted in a size-dependent cytotoxicity in cultured primary osteoblasts, and reactive oxygen species generation should be one possible damage pathway for the toxicological effects produced by yttrium oxide particles. The results may provide useful information for more rational applications of yttrium oxide nanoparticles in the future.

Oxidative stress as a damage mechanism in porcine cumulus-oocyte complexes exposed to malathion during in vitro maturation.

PubMed

Flores, Diana; Souza, Verónica; Betancourt, Miguel; Teteltitla, Mario; González-Márquez, Humberto; Casas, Eduardo; Bonilla, Edmundo; Ramírez-Noguera, Patricia; Gutiérrez-Ruíz, María Concepción; Ducolomb, Yvonne

2017-06-01

Malathion is one of the most commonly used insecticides. Recent findings have demonstrated that it induces oxidative stress in somatic cells, but there are not enough studies that have demonstrated this effect in germ cells. Malathion impairs porcine oocyte viability and maturation, but studies have not shown how oxidative stress damages maturation and which biochemical mechanisms are affected in this process in cumulus-oocyte complexes (COCs). The aims of the present study were to determine the amount of oxidative stress produced by malathion in porcine COCs matured in vitro, to define how biochemical mechanisms affect this process, and determine whether trolox can attenuate oxidative damage. Sublethal concentrations 0, 750, and 1000 µM were used to evaluate antioxidant enzyme expressions, reactive oxygen species (ROS production), protein oxidation, and lipid peroxidation, among other oxidation products. COCs viability and oocyte maturation decreased in a concentration-dependent manner. Malathion increased Cu, Zn superoxide dismutase (SOD1), glutathione-S-transferase (GST), and glucose 6 phosphate dehydrogenase (G6PD) protein level and decreased glutathione peroxidase (GSH-Px) and catalase (CAT) protein level. Species reactives of oxygen (ROS), protein oxidation and Thiobarbituric acid reactive substances (TBARS) levels increased in COCs exposed to the insecticide, but when COCs were pre-treated with the trolox (50 µM) 30 min before and during malathion exposure, these parameters decreased down to control levels. This study showed that malathion has a detrimental effect on COCs during in vitro maturation, inducing oxidative stress, while trolox attenuated malathion toxicity by decreasing oxidative damage. © 2017 Wiley Periodicals, Inc.

Rebamipide, a novel antiulcer agent, attenuates Helicobacter pylori induced gastric mucosal cell injury associated with neutrophil derived oxidants.

PubMed Central

Suzuki, M; Miura, S; Mori, M; Kai, A; Suzuki, H; Fukumura, D; Suematsu, M; Tsuchiya, M

1994-01-01

The effect of rebamipide, a novel antiulcer compound, on Helicobacter pylori activated neutrophil dependent in vitro gastric epithelial cell injury was investigated. Luminol dependent chemiluminescence (ChL), which detects toxic oxidants from neutrophils exhibited a 12-fold increase when the bacterial suspension of H pylori was added to the isolated human neutrophils. This change was significantly attenuated by rebamipide at a concentration less than 1 mM, showing that rebamipide may inhibit oxidant production from H pylori elicited neutrophils. To assess whether rebamipide attenuates gastric mucosal injury, we tested its inhibitory action on H pylori induced gastric mucosal damage associated with neutrophils in vitro. Rabbit gastric mucosal cells were monolayered in culture wells and coincubated with human neutrophils and H pylori, and the cytotoxicity index was then calculated. Cultured gastric cells were significantly damaged when they were incubated with human neutrophils activated by H pylori. This cellular damage was attenuated by rebamipide in a dose-dependent manner. Furthermore, spectrophotometrical measurement showed that rebamipide (1 mM) inhibits urease activity by 21.7%. As monochloramine (an oxidant yielded by reaction of neutrophil derived chlorinated oxidant and ammonia) is proposed as an important toxic molecule in this model, the current findings suggest that the preventive effect of rebamipide on H pylori elicited neutrophil induced gastric mucosal injury may result from its inhibitory actions on the neutrophilic oxidative burst as well as H pylori derived urease activity. PMID:7959190

Quercitrin Protects Skin from UVB-induced Oxidative Damage

PubMed Central

Yin, Yuanqin; Li, Wenqi; Son, Yong-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. PMID:23545178

Quercitrin protects skin from UVB-induced oxidative damage.

PubMed

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

2013-06-01

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. Copyright © 2013 Elsevier Inc. All rights reserved.

Scavenging of reactive oxygen species and prevention of oxidative neuronal cell damage by a novel gallotannin, pistafolia A.

PubMed

Wei, Taotao; Sun, Handong; Zhao, Xingyu; Hou, Jingwu; Hou, Aijun; Zhao, Qinshi; Xin, Wenjuan

2002-03-08

Pistafolia A is a novel gallotannin isolated from the leaf extract of Pistacia weinmannifolia. In the present investigation, the ability of Pistafolia A to scavenge reactive oxygen species including hydroxyl radicals and superoxide anion was measured by ESR spin trapping technique. The inhibition effect on iron-induced lipid peroxidaiton in liposomes was studied. The protective effects of Pistafolia A against oxidative neuronal cell damage and apoptosis induced by peroxynitrite were also assessed. The results showed that Pistafolia A could scavenge both hydroxyl radicals and superoxide anion dose-dependently and inhibit lipid peroxidation effectively. In cerebellar granule cells pretreated with Pistafolia A, peroxynitrite-induced oxidative neuronal damage and apoptosis were prevented markedly. The antioxidant capacity of Pistafolia A was much more potent then that of the water-soluble analog of vitamin E, Trolox. The results suggested that Pistafolia A might be used as an effective natural antioxidant for the prevention and cure of neuronal diseases associated with the production of peroxynitrite and related reactive oxygen species.

The role of the iron catalyst in the toxicity of multi-walled carbon nanotubes (MWCNTs).

PubMed

Visalli, Giuseppa; Facciolà, Alessio; Iannazzo, Daniela; Piperno, Anna; Pistone, Alessandro; Di Pietro, Angela

2017-09-01

This study aimed to investigate the role of iron, used as a catalyst, in the biological response to pristine and functionalized multi-walled carbon nanotubes (p/fMWCNTs) with an iron content of 2.5-2.8%. Preliminarily, we assessed the pro-oxidant activity of MWCNTs-associated iron by an abiotic test. To evaluate iron bioavailability, we measured intracellular redox-active iron in A549 cells exposed to both MWCNT suspensions and to the cell medium preconditioned by MWCNTs, in order to assess the iron dissolution rate under physiological conditions. Moreover, in exposed cells, we detected ROS levels, 8-oxo-dG and mitochondrial function. The results clearly highlighted that MWCNTs- associated iron was not redox-active and that iron leakage did not occur under physiological conditions, including the oxidative burst of specialized cells. Despite this, in MWCNTs exposed cells, higher level of intracellular redox-active iron was measured in comparison to control and a significant time-dependent ROS increase was observed (P<0.01). Higher levels of 8-oxo-dG, a marker of oxidative DNA damage, and decreased mitochondrial function, confirmed the oxidative stress induced by MWCNTs. Based on the results we believe that oxidative damage could be attributable to the release of endogenous redox-active iron. This was due to the damage of acidic vacuolar compartment caused by endocytosis-mediated MWCNT internalization. Copyright © 2017 Elsevier GmbH. All rights reserved.

Comparative analysis of the relative potential of silver, zinc-oxide and titanium-dioxide nanoparticles against UVB-induced DNA damage for the prevention of skin carcinogenesis

PubMed Central

Arora, Sumit; Omar, Yousef; Ijaz, Zohaib Mohammad; AL-Ghadhban, Ahmed; Deshmukh, Sachin K.; Carter, James E.; Singh, Ajay P.; Singh, Seema

2016-01-01

Sunscreen formulations containing UVB filters, such as Zinc-oxide (ZnO) and titanium-dioxide (TiO2) nanoparticles (NPs) have been developed to limit the exposure of human skin to UV-radiations. Unfortunately, these UVB protective agents have failed in controlling the skin cancer incidence. We recently demonstrated that silver nanoparticles (Ag-NPs) could serve as novel protective agents against UVB-radiations. Here our goal was to perform comparative analysis of direct and indirect UVB-protection efficacy of ZnO-, TiO2- and Ag-NPs. Sun-protection-factor calculated based on their UVB-reflective/absorption abilities was the highest for TiO2-NPs followed by Ag- and ZnO-NPs. This was further confirmed by studying indirect protection of UVB radiation-induced death of HaCaT cells. However, only Ag-NPs were active in protecting HaCaT cells against direct UVB-induced DNA-damage by repairing bulky-DNA lesions through nucleotide-excision-repair mechanism. Moreover, Ag-NPs were also effective in protecting HaCaT cells from UVB-induced oxidative DNA damage by enhancing SOD/CAT/GPx activity. In contrast, ZnO- and TiO2-NPs not only failed in providing any direct protection from DNA-damage, but rather enhanced oxidative DNA-damage by increasing ROS production. Together, these findings raise concerns about safety of ZnO- and TiO2-NPs and establish superior protective efficacy of Ag-NPs. PMID:27693632

Antidiabetics and diuretics show phototoxicity in HaCaT cells

NASA Astrophysics Data System (ADS)

Selvaag, Edgar; Petersen, Anita B.; Gniadecki, Robert; Thorn, Tine; Wulf, Hans Christian

2001-10-01

The antidiabetics tolbutamide, glibenclamide, and glipizide, and the diuretics bendroflumethiazide, butizide, furosemide, hydrochlorothiazide, and trichlormethiazide were investigated for potential phototoxicity in the HaCaT cell line. The cells were incubated with the drugs and then exposed to UVA1 irradiation. The effects of the antioxidants L-ascorbic acid, and (alpha) -tocopherol on oxidative DNA damage were assessed. Bendroflumethiazide, furosemide, hydrochlorothiazide, trichlormethiazide, or tolbutamide induced dose-dependent phototoxicity. Cells incubated with bendroflumethiazide, tolbutamide, and glibenclamide, and irradiated with UVA1 demonstrated an increased oxidative DNA damage. Pre-treatment with L-ascorbic acid, or (alpha) -tocopherol, suppressed the UVA-induced DNA damage in cells incubated with 1 mM of bendroflumethiazide, furosemide, glibenclamide, glipizide, tolbutamide, and trichloromethiazide, further implying the involvement of reactive oxygen species in the phototoxic DNA damage. These results may indicate a link between phototoxic and photocancerogenic potential of the sulfonamide-derived oral antidiabetic and diuretic drugs, as it has previously been recognized for psoralen, chlorpromazine, and fluoroquinolones. Excessive exposure to UV light may be deleterious for patients treated with these drugs.

Lutein and zeaxanthin supplementation reduces photo-oxidative damage and modulates the expression of inflammation related genes in retinal pigment epithelial cells

USDA-ARS?s Scientific Manuscript database

Oxidative damage and inflammation are related to the pathogenesis of age-related macular degeneration (AMD). Epidemiologic studies suggest that insufficient dietary lutein and zeaxanthin intake or lower serum zeaxanthin levels are associated with increased risk for AMD. The objective of this work w...

H2S Protects Against Methionine–Induced Oxidative Stress in Brain Endothelial Cells

PubMed Central

Tyagi, Neetu; Moshal, Karni S.; Sen, Utpal; Vacek, Thomas P.; Kumar, Munish; Hughes, William M.; Kundu, Soumi

2009-01-01

Abstract Homocysteine (Hcy) causes cerebrovascular dysfunction by inducing oxidative stress. However, to date, there are no strategies to prevent Hcy-induced oxidative damage. Hcy is an H2S precursor formed from methionine (Met) metabolism. We aimed to investigate whether H2S ameliorated Met-induced oxidative stress in mouse brain endothelial cells (bEnd3). The bEnd3 cells were exposed to Met treatment in the presence or absence of NaHS (donor of H2S). Met-induced cell toxicity increased the levels of free radicals in a concentration-dependent manner. Met increased NADPH-oxidase-4 (NOX-4) expression and mitigated thioredxion-1(Trx-1) expression. Pretreatment of bEnd3 with NaHS (0.05 mM) attenuated the production of free radicals in the presence of Met and protected the cells from oxidative damage. Furthermore, NaHS enhanced inhibitory effects of apocynin, N-acetyl-l-cysteine (NAC), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), Nω-nitro-l-arginine methyl ester (L-NAME) on ROS production and redox enzymes levels induced by Met. In conclusion, the administration of H2S protected the cells from oxidative stress induced by hyperhomocysteinemia (HHcy), which suggested that NaHS/H2S may have therapeutic potential against Met-induced oxidative stress. Antioxid. Redox Signal. 11, 25–33. PMID:18837652

SOD2 deficiency in hematopoietic cells in mice results in reduced red blood cell deformability and increased heme degradation

PubMed Central

Mohanty, Joy G.; Nagababu, Enika; Friedman, Jeffrey S.; Rifkind, Joseph M.

2013-01-01

Among the three types of super oxide dismutases (SODs) known, SOD2 deficiency is lethal in neonatal mice owing to cardiomyopathy caused by severe oxidative damage. SOD2 is found in red blood cell (RBC) precursors, but not in mature RBCs. To investigate the potential damage to mature RBCs resulting from SOD2 deficiency in precursor cells, we studied RBCs from mice in which fetal liver stem cells deficient in SOD2 were capable of efficiently rescuing lethally irradiated host animals. These transplanted animals lack SOD2 only in hematopoietically generated cells and live longer than SOD2 knockouts. In these mice, approximately 2.8% of their total RBCs in circulation are iron-laden reticulocytes, with numerous siderocytic granules and increased protein oxidation similar to that seen in sideroblastic anemia. We have studied the RBC deformability and oxidative stress in these animals and the control group by measuring them with a microfluidic ektacytometer and assaying fluorescent heme degradation products with a fluorimeter, respectively. In addition, the rate of hemoglobin oxidation in RBCs from these mice and the control group were measured spectrophotometrically. The results show that RBCs from these SOD2-deficient mice have reduced deformability, increased heme degradation products, and an increased rate of hemoglobin oxidation compared with control animals, indicative of increased RBC oxidative stress. PMID:23142655

Oxidative stress damage as a detrimental factor in preterm birth pathology.

PubMed

Menon, Ramkumar

2014-01-01

Normal term and spontaneous preterm births (PTB) are documented to be associated with oxidative stress (OS), and imbalances in the redox system (balance between pro- and antioxidant) have been reported in the maternal-fetal intrauterine compartments. The exact mechanism of labor initiation either at term or preterm by OS is still unclear, and this lack of understanding can partially be blamed for failure of antioxidant supplementation trials in PTB prevention. Based on recent findings from our laboratory, we postulate heterogeneity in host OS response. The physiologic (at term) and pathophysiologic (preterm) pathways of labor are not mediated by OS alone but by OS-induced damage to intrauterine tissues, especially fetal membranes of the placenta. OS damage affects all major cellular elements in the fetal cells, and this damage promotes fetal cell senescence (aging). The aging of the fetal cells is predominated by p38 mitogen activated kinase (p38MAPK) pathways. Senescing cells generate biomolecular signals that are uterotonic, triggering labor process. The aging of fetal cells is normal at term. However, aging is premature in PTB, especially in those PTBs complicated by preterm premature rupture of the membranes, where elements of redox imbalances and OS damage are more dominant. We postulate that fetal cell senescence signals generated by OS damage are likely triggers for labor. This review highlights the mechanisms involved in senescence development at term and preterm by OS damage and provides insight into novel fetal signals of labor initiation pathways.

Oxidative Stress Damage as a Detrimental Factor in Preterm Birth Pathology

PubMed Central

Menon, Ramkumar

2014-01-01

Normal term and spontaneous preterm births (PTB) are documented to be associated with oxidative stress (OS), and imbalances in the redox system (balance between pro- and antioxidant) have been reported in the maternal–fetal intrauterine compartments. The exact mechanism of labor initiation either at term or preterm by OS is still unclear, and this lack of understanding can partially be blamed for failure of antioxidant supplementation trials in PTB prevention. Based on recent findings from our laboratory, we postulate heterogeneity in host OS response. The physiologic (at term) and pathophysiologic (preterm) pathways of labor are not mediated by OS alone but by OS-induced damage to intrauterine tissues, especially fetal membranes of the placenta. OS damage affects all major cellular elements in the fetal cells, and this damage promotes fetal cell senescence (aging). The aging of the fetal cells is predominated by p38 mitogen activated kinase (p38MAPK) pathways. Senescing cells generate biomolecular signals that are uterotonic, triggering labor process. The aging of fetal cells is normal at term. However, aging is premature in PTB, especially in those PTBs complicated by preterm premature rupture of the membranes, where elements of redox imbalances and OS damage are more dominant. We postulate that fetal cell senescence signals generated by OS damage are likely triggers for labor. This review highlights the mechanisms involved in senescence development at term and preterm by OS damage and provides insight into novel fetal signals of labor initiation pathways. PMID:25429290

Role of Oxidative Stress in Transformation Induced by Metal Mixture

PubMed Central

Martín, Silva-Aguilar; Emilio, Rojas; Mahara, Valverde

2011-01-01

Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity. PMID:22191014

Expression of the genetic suppressor element 24.2 (GSE24.2) decreases DNA damage and oxidative stress in X-linked dyskeratosis congenita cells.

PubMed

Manguan-Garcia, Cristina; Pintado-Berninches, Laura; Carrillo, Jaime; Machado-Pinilla, Rosario; Sastre, Leandro; Pérez-Quilis, Carme; Esmoris, Isabel; Gimeno, Amparo; García-Giménez, Jose Luis; Pallardó, Federico V; Perona, Rosario

2014-01-01

The predominant X-linked form of Dyskeratosis congenita results from mutations in DKC1, which encodes dyskerin, a protein required for ribosomal RNA modification that is also a component of the telomerase complex. We have previously found that expression of an internal fragment of dyskerin (GSE24.2) rescues telomerase activity in X-linked dyskeratosis congenita (X-DC) patient cells. Here we have found that an increased basal and induced DNA damage response occurred in X-DC cells in comparison with normal cells. DNA damage that is also localized in telomeres results in increased heterochromatin formation and senescence. Expression of a cDNA coding for GSE24.2 rescues both global and telomeric DNA damage. Furthermore, transfection of bacterial purified or a chemically synthesized GSE24.2 peptide is able to rescue basal DNA damage in X-DC cells. We have also observed an increase in oxidative stress in X-DC cells and expression of GSE24.2 was able to diminish it. Altogether our data indicated that supplying GSE24.2, either from a cDNA vector or as a peptide reduces the pathogenic effects of Dkc1 mutations and suggests a novel therapeutic approach.

ELECTROSTATIC CHARGE ON NANO-PARTICLES ACTIVATES CNS MACROPHAGES (MICROGLIA).

EPA Science Inventory

Nanometer size particles carry free radical activity on their surface and can produce oxidative stress (OS)-mediated damage upon impact to target cells. The initiating event of phage cell activation (i.e., the oxidative burst) is unknown, although many proximal events have been i...

Interspecific correlation between red blood cell mitochondrial ROS production, cardiolipin content and longevity in birds.

PubMed

Delhaye, Jessica; Salamin, Nicolas; Roulin, Alexandre; Criscuolo, François; Bize, Pierre; Christe, Philippe

2016-12-01

Mitochondrial respiration releases reactive oxygen species (ROS) as by-products that can damage the soma and may in turn accelerate ageing. Hence, according to "the oxidative stress theory of ageing", longer-lived organisms may have evolved mechanisms that improve mitochondrial function, reduce ROS production and/or increase cell resistance to oxidative damage. Cardiolipin, an important mitochondrial inner-membrane phospholipid, has these properties by binding and stabilizing mitochondrial inner-membrane proteins. Here, we investigated whether ROS production, cardiolipin content and cell membrane resistance to oxidative attack in freshly collected red blood cells (RBCs) are associated with longevity (range 5-35 years) in 21 bird species belonging to seven Orders. After controlling for phylogeny, body size and oxygen consumption, variation in maximum longevity was significantly explained by mitochondrial ROS production and cardiolipin content, but not by membrane resistance to oxidative attack. RBCs of longer-lived species produced less ROS and contained more cardiolipin than RBCs of shorter-lived species did. These results support the oxidative stress theory of ageing and shed light on mitochondrial cardiolipin as an important factor linking ROS production to longevity.

Protection by the flavonoids quercetin and luteolin against peroxide- or menadione-induced oxidative stress in MC3T3-E1 osteoblast cells.

PubMed

Fatokun, Amos A; Tome, Mercedes; Smith, Robert A; Darlington, L Gail; Stone, Trevor W

2015-01-01

Potential protective effects of the flavonoids quercetin and luteolin have been examined against the oxidative stress of MC3T3-E1 osteoblast-like cells. Although hydrogen peroxide and menadione reduced cell viability, the toxicity was prevented by desferrioxamine or catalase but not superoxide dismutase, suggesting the involvement of hydrogen peroxide in both cases. Quercetin and luteolin reduced the oxidative damage, especially that caused by hydrogen peroxide. When cultures were pre-incubated with quercetin or luteolin, protection was reduced or lost. Protection was also reduced when a 24 h pre-incubation with the flavonoids was followed by exposure to menadione alone. Pretreating cultures with luteolin impaired protection by quercetin, whereas quercetin pretreatment did not affect protection by luteolin. It is concluded that quercetin and luteolin suppress oxidative damage to MC3T3-E1 cells, especially caused by peroxide. The reduction in protection by pretreatment implies a down-regulation of part of the toxic transduction pathway.

Optimization of the C11-BODIPY(581/591) dye for the determination of lipid oxidation in Chlamydomonas reinhardtii by flow cytometry.

PubMed

Cheloni, Giulia; Slaveykova, Vera I

2013-10-01

Lipid oxidation is a recognized end point for the study of oxidative stress and is an important parameter to describe the mode of micropollutant action on aquatic microorganisms. Therefore, the development of quick and reliable methodologies probing the oxidative stress and damage in living cells is highly sought. In the present proof-of-concept work, we examined the potential of the fluorescent dye C11-BODIPY(591/581) to probe lipid oxidation in the green microalga Chlamydomonas reinhardtii. C11-BODIPY(591/581) staining was combined with flow cytometry measurements to obtain multiparameter information on cellular features and oxidative stress damage within single cells. First, staining conditions were optimized by exploring the capability of the dye to stain algal cells under increasing cell and dye concentrations and different staining procedures. Then lipid oxidation in algae induced by short- and long-term exposures to the three metallic micropollutants, copper, mercury, and nanoparticulate copper oxide, and the two organic contaminants, diethyldithiocarbamate (DDC) and diuron was determined. In this work we pointed out C11-BODIPY(591/581) applicability in a wide range of exposure conditions, including studies of oxidation as a function of time and that it is suitable for in vivo measurements of lipid oxidation due to its high permeation and stability in cells and its low interference with algal autofluorescence. © 2013 International Society for Advancement of Cytometry. Copyright © 2013 International Society for Advancement of Cytometry.

CD44-targeted hyaluronic acid-curcumin prodrug protects renal tubular epithelial cell survival from oxidative stress damage.

PubMed

Hu, Jing-Bo; Li, Shu-Juan; Kang, Xu-Qi; Qi, Jing; Wu, Jia-Hui; Wang, Xiao-Juan; Xu, Xiao-Ling; Ying, Xiao-Ying; Jiang, Sai-Ping; You, Jian; Du, Yong-Zhong

2018-08-01

Based on the abnormally increased expression of CD44 receptors on renal tubule epithelial cells during ischemia/reperfusion-induced acute kidney injury (AKI), we developed a hyaluronic acid-curcumin (HA-CUR) polymeric prodrug targeting to epithelial cells and then relieving oxidative stress damages. The water solubility of HA-CUR was significantly enhanced and approximately 27-fold higher than that of CUR. Cellular uptake test showed HA-CUR was preferably internalized by H 2 O 2 -pretreated tubular epithelial (HK-2) cells compared with free CUR benefiting from the specific binding between HA and CD44 receptors. Biodistribution results further demonstrated the increased accumulation of HA-CUR in kidneys with 13.9-fold higher than that of free CUR. Pharmacodynamic studies indicated HA-CUR effectively ameliorated AKI, and the exact mechanism was that HA-CUR protected renal tubule epithelial cells from oxidative stress damage via inhibiting PtdIns3K-AKT-mTOR signaling pathway. Taken together, this study provides a new therapeutic strategy for the treatment of AKI based on the pathogenesis of the disease. Copyright © 2018 Elsevier Ltd. All rights reserved.

Disruption of Redox Homeostasis in Tumor Necrosis Factor-Induced Apoptosis in a Murine Hepatocyte Cell Line

PubMed Central

Pierce, Robert H.; Campbell, Jean S.; Stephenson, Alyssa B.; Franklin, Christopher C.; Chaisson, Michelle; Poot, Martin; Kavanagh, Terrance J.; Rabinovitch, Peter S.; Fausto, Nelson

2000-01-01

Tumor necrosis factor (TNF) is a mediator of the acute phase response in the liver and can initiate proliferation and cause cell death in hepatocytes. We investigated the mechanisms by which TNF causes apoptosis in hepatocytes focusing on the role of oxidative stress, antioxidant defenses, and mitochondrial damage. The studies were conducted in cultured AML12 cells, a line of differentiated murine hepatocytes. As is the case for hepatocytes in vivo, AML12 cells were not sensitive to cell death by TNF alone, but died by apoptosis when exposed to TNF and a small dose of actinomycin D (Act D). Morphological signs of apoptosis were not detected until 6 hours after the treatment and by 18 hours ∼50% of the cells had died. Exposure of the cells to TNF+Act D did not block NFκB nuclear translocation, DNA binding, or its overall transactivation capacity. Induction of apoptosis was characterized by oxidative stress indicated by the loss of NAD(P)H and glutathione followed by mitochondrial damage that included loss of mitochondrial membrane potential, inner membrane structural damage, and mitochondrial condensation. These changes coincided with cytochrome C release and the activation of caspases-8, -9, and -3. TNF-induced apoptosis was dependent on glutathione levels. In cells with decreased levels of glutathione, TNF by itself in the absence of transcriptional blocking acted as an apoptotic agent. Conversely, the antioxidant α-lipoic acid, that protected against the loss of glutathione in cells exposed to TNF+Act D completely prevented mitochondrial damage, caspase activation, cytochrome C release, and apoptosis. The results demonstrate that apoptosis induced by TNF+Act D in AML12 cells involves oxidative injury and mitochondrial damage. As injury was regulated to a larger extent by the glutathione content of the cells, we suggest that the combination of TNF+Act D causes apoptosis because Act D blocks the transcription of genes required for antioxidant defenses. PMID:10880392

Protection against UVB-induced oxidative stress in human skin cells and skin models by methionine sulfoxide reductase A.

PubMed

Pelle, Edward; Maes, Daniel; Huang, Xi; Frenkel, Krystyna; Pernodet, Nadine; Yarosh, Daniel B; Zhang, Qi

2012-01-01

Environmental trauma to human skin can lead to oxidative damage of proteins and affect their activity and structure. When methionine becomes oxidized to its sulfoxide form, methionine sulfoxide reductase A (MSRA) reduces it back to methionine. We report here the increase in MSRA in normal human epidermal keratinocytes (NHEK) after ultraviolet B (UVB) radiation, as well as the reduction in hydrogen peroxide levels in NHEK pre-treated with MSRA after exposure. Further, when NHEK were pre-treated with a non-cytotoxic pentapeptide containing methionine sulfoxide (metSO), MSRA expression increased by 18.2%. Additionally, when the media of skin models were supplemented with the metSO pentapeptide and then exposed to UVB, a 31.1% reduction in sunburn cells was evident. We conclude that the presence of MSRA or an externally applied peptide reduces oxidative damage in NHEK and skin models and that MSRA contributes to the protection of proteins against UVB-induced damage in skin.

Copper-mediated DNA damage by the neurotransmitter dopamine and L-DOPA: A pro-oxidant mechanism.

PubMed

Rehmani, Nida; Zafar, Atif; Arif, Hussain; Hadi, Sheikh Mumtaz; Wani, Altaf A

2017-04-01

Oxidative DNA damage has been implicated in the pathogenesis of neurological disorders, cancer and ageing. Owing to the established link between labile copper concentrations and neurological diseases, it is critical to explore the interactions of neurotransmitters and drug supplements with copper. Herein, we investigate the pro-oxidant DNA damage induced by the interaction of L-DOPA and dopamine (DA) with copper. The DNA binding affinity order of the compounds has been determined by in silico molecular docking. Agarose gel electrophoresis reveals that L-DOPA and DA are able to induce strand scission in plasmid pcDNA3.1 (+/-) in a copper dependent reaction. These metabolites also cause cellular DNA breakage in human lymphocytes by mobilizing endogenous copper, as assessed by comet assay. Further, L-DOPA and DA-mediated DNA breaks were detected by the appearance of post-DNA damage sensitive marker γH2AX in cancer cell lines accumulating high copper. Immunofluorescence demonstrated the co-localization of downstream repair factor 53BP1 at the damaged induced γH2AX foci in cancer cells. The present study corroborates and provides a mechanism to the hypothesis that suggests metal-mediated oxidation of catecholamines contributes to the pathogenesis of neurodegenerative diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transgenic Mouse Model for Reducing Oxidative Damage in Bone

NASA Technical Reports Server (NTRS)

Schreurs, Ann-Sofie; Torres, S.; Truong, T.; Moyer, E. L.; Kumar, A.; Tahimic, Candice C. G.; Alwood, J. S.; Limoli, C. L.; Globus, R. K.

2016-01-01

Bone loss can occur due to many challenges such age, radiation, microgravity, and Reactive Oxygen Species (ROS) play a critical role in bone resorption by osteoclasts (Bartell et al. 2014). We hypothesize that suppression of excess ROS in skeletal cells, both osteoblasts and osteoclasts, regulates skeletal growth and remodeling. To test our hypothesis, we used transgenic mCAT mice which overexpress the human anti-oxidant catalase gene targeted to the mitochondria, the main site for endogenous ROS production. mCAT mice have a longer life-span than wildtype controls and have been used to study various age-related disorders. To stimulate remodeling, 16 week old mCAT mice or wildtype mice were exposed to treatment (hindlimb-unloading and total body-irradiation) or sham treatment conditions (control). Tissues were harvested 2 weeks later for skeletal analysis (microcomputed tomography), biochemical analysis (gene expression and oxidative damage measurements), and ex vivo bone marrow derived cell culture (osteoblastogenesis and osteoclastogenesis). mCAT mice expressed the transgene and displayed elevated catalase activity in skeletal tissue and marrow-derived osteoblasts and osteoclasts grown ex vivo. In addition, when challenged with treatment, bone tissues from wildtype mice showed elevated levels of malondialdehyde (MDA), indicating oxidative damage) whereas mCAT mice did not. Correlation analysis revealed that increased catalase activity significantly correlated with decreased MDA levels and that increased oxidative damage correlated with decreased percent bone volume (BVTV). In addition, ex-vivo cultured osteoblast colony growth correlated with catalase activity in the osteoblasts. Thus, we showed that these transgenic mice can be used as a model to study the relationship between markers of oxidative damage and skeletal properties. mCAT mice displayed reduced BVTV and trabecular number relative to wildtype mice, as well as increased structural model index in the cancellous tibia. Treatment caused bone loss in wildtype mice, as expected. Treatment also caused deficits in microarchitecture of mCAT mice, although less severe than wildtype mice in some parameters (percent bone volume, structural model index and cortical area). In conclusion, our results indicate that endogenous ROS signaling in both osteoblast and osteoclast lineage cells contributes to skeletal growth and remodeling, and quenching oxidative damage could play a role in bone loss prevention.

Comparative DNA damage and transcriptomic effects of engineered nanoparticles in human lung cells in vitro

EPA Science Inventory

A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), various types of DNA damage, and transcriptional changes in human respiratory BEAS-2B cells exposed in vitro at se...

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

PubMed

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.

Induction of oxidative stress, DNA damage, and apoptosis in a malignant human skin melanoma cell line after exposure to zinc oxide nanoparticles

PubMed Central

Alarifi, Saud; Ali, Daoud; Alkahtani, Saad; Verma, Ankit; Ahamed, Maqusood; Ahmed, Mukhtar; Alhadlaq, Hisham A

2013-01-01

The widespread use of zinc oxide (ZnO) nanoparticles worldwide exposes humans to their adverse effects, so it is important to understand their biological effects and any associated risks. This study was designed to investigate the cytotoxicity, oxidative stress, and apoptosis caused by ZnO nanoparticles in human skin melanoma (A375) cells. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] and lactate dehydrogenase-based cell viability assays showed a significant decrease in cell viability after exposure to ZnO nanoparticles, and phase contrast images revealed that cells treated with these nanoparticles had a lower density and a rounded morphology. ZnO nanoparticles were also found to induce oxidative stress, evidenced by generation of reactive oxygen species and depletion of the antioxidant, glutathione. Induction of apoptosis was confirmed by chromosomal condensation assay and caspase-3 activation. Further, more DNA damage was observed in cells exposed to the highest concentration of ZnO nanoparticles. These results demonstrate that ZnO nanoparticles have genotoxic potential in A375 cells, which may be mediated via oxidative stress. Our short-term exposure study showing induction of a genotoxic and apoptotic response to ZnO nanoparticles needs further investigation to determine whether there may be consequences of long-term exposure to ZnO nanoparticles. PMID:23493450

Alkaline Comet Assay for Assessing DNA Damage in Individual Cells.

PubMed

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.

Modulation of proteostasis counteracts oxidative stress and affects DNA base excision repair capacity in ATM-deficient cells

PubMed Central

Yang, Di; Fletcher, Sally C.; Vendrell, Iolanda; Fischer, Roman; Legrand, Arnaud J.

2017-01-01

Abstract Ataxia telangiectasia (A-T) is a syndrome associated with loss of ATM protein function. Neurodegeneration and cancer predisposition, both hallmarks of A-T, are likely to emerge as a consequence of the persistent oxidative stress and DNA damage observed in this disease. Surprisingly however, despite these severe features, a lack of functional ATM is still compatible with early life, suggesting that adaptation mechanisms contributing to cell survival must be in place. Here we address this gap in our knowledge by analysing the process of human fibroblast adaptation to the lack of ATM. We identify profound rearrangement in cellular proteostasis occurring very early on after loss of ATM in order to counter protein damage originating from oxidative stress. Change in proteostasis, however, is not without repercussions. Modulating protein turnover in ATM-depleted cells also has an adverse effect on the DNA base excision repair pathway, the major DNA repair system that deals with oxidative DNA damage. As a consequence, the burden of unrepaired endogenous DNA lesions intensifies, progressively leading to genomic instability. Our study provides a glimpse at the cellular consequences of loss of ATM and highlights a previously overlooked role for proteostasis in maintaining cell survival in the absence of ATM function. PMID:28973444

SIRT3 mediates decrease of oxidative damage and prevention of ageing in porcine fetal fibroblasts.

PubMed

Xie, Xiaoxian; Wang, Liangliang; Zhao, Binggong; Chen, Yangyang; Li, Jiaqi

2017-05-15

Sirtuin 3 (SIRT3) is a mitochondria-specific protein required for the deacetylation of metabolic enzymes and the action of oxidative phosphorylation by acting as a nicotinamide adenine dinucleotide (NAD + )-dependent deacetylase. SIRT3 increases oxidative stress resistance and prevents mitochondrial decay associated with ageing in response to caloric restriction. However, the effects of SIRT3 on oxidative damage and ageing are not well understood. We investigated the physiological functions of porcine SIRT3 on the damage and ageing in porcine fetal fibroblasts (PFFs). Overexpression and knockdown of SIRT3 were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis, respectively. All cells were treated with three different stress reagents 12-o-tetradecanoylphorbol-13-acetate (TPA), methanesulfonic acid methylester (MMS), and tert-butylhydroperoxide (t-BHP), respectively, and then examined by flow cytometry following JC-1 (5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethylbenzimidazol-carbocyanine iodide) staining. SIRT3 overexpression enhanced the ability of superoxide dismutase 2 (SOD2) to reduce cellular reactive oxygen species (ROS), which further decreased the damage to the membranes and the organelles of the cells, especially to mitochondria. It inhibited the initial decrease of mitochondrial membrane potential, and prevented the decrease of adenosine triphosphate (ATP) production and activity of Nampt. In contrast, SIRT3 knockdown reduced the ability of SOD2 to increase cellular ROS which was directly correlated with stress-induced oxidative damage and ageing in PFFs. Our findings identify one function of SIRT3 in PFFs was to dampen cytotoxicity, and, therefore, to decrease oxidative damage and attenuate ageing possibly by enhancing the activity of SOD2. Copyright © 2017 Elsevier Inc. All rights reserved.

Clustered DNA damages induced by high and low LET radiation, including heavy ions

NASA Technical Reports Server (NTRS)

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

2001-01-01

Clustered DNA damages--here defined as two or more lesions (strand breaks, oxidized purines, oxidized pyrimidines or abasic sites) within a few helical turns--have been postulated as difficult to repair accurately, and thus highly significant biological lesions. Further, attempted repair of clusters may produce double strand breaks (DSBs). However, until recently, there was no way to measure ionizing radiation-induced clustered damages, except DSB. We recently described an approach for measuring classes of clustered damages (oxidized purine clusters, oxidized pyrimidine clusters, abasic clusters, along with DSB). We showed that ionizing radiation (gamma rays and Fe ions, 1 GeV/amu) does induce such clusters in genomic DNA in solution and in human cells. These studies also showed that each damage cluster results from one radiation hit (and its track), thus indicating that they can be induced by very low doses of radiation, i.e. two independent hits are not required for cluster induction. Further, among all complex damages, double strand breaks comprise--at most-- 20%, with the other clustered damages being at least 80%.

Radical-scavenging abilities and antioxidant properties of theaflavins and their gallate esters in H2O2-mediated oxidative damage system in the HPF-1 cells.

PubMed

Yang, Ziyin; Jie, Guoliang; Dong, Fang; Xu, Yi; Watanabe, Naoharu; Tu, Youying

2008-08-01

The antioxidant properties of theaflavins and their gallate esters, namely theaflavin (TF1), theaflavin-3(3')-gallate (TF2) and theaflavin-3,3'-digallate (TF3) were investigated by comparing with epigallocatechin gallate (EGCG). The order of hydroxyl radicals-scavenging ability was TF3>TF2>TF1>EGCG. The order of 2,2-diphenyl-1-picrylhydrazyl scavenging ability was TF3>TF2>EGCG>TF1. TF1, TF2, and TF3 showed more effective effects than EGCG in protection against H2O2-mediated damage in HPF-1 cells. TF2 was the most potent accelerant of HPF-1 cell proliferation. TF1, TF2 and TF3 suppressed the accumulation of intracellular reactive species in H2O2-mediated damage HPF-1 cells. Pre-treated for 2h and eliminated from the cells, TF1 and TF3 still showed protective effects against H2O2-mediated damage in HPF-1 cells. This suggests that the protective effects of TF1 and TF3 on oxidative damage HPF-1 cells may be responsible for other mechanisms, rather than only scavenging the already formed reactive species. It remains to be determined whether TF1 and TF3 improved the normal HPF-1 cell resistive abilities toward radical-damage in pre-treatment. Further studies of the effects of theaflavins on some enzymes or signal transduction in the normal HPF-1 cells are underway.

Involvement of oxidatively damaged DNA and repair in cancer development and aging

PubMed Central

Tudek, Barbara; Winczura, Alicja; Janik, Justyna; Siomek, Agnieszka; Foksinski, Marek; Oliński, Ryszard

2010-01-01

DNA damage and DNA repair may mediate several cellular processes, like replication and transcription, mutagenesis and apoptosis and thus may be important factors in the development and pathology of an organism, including cancer. DNA is constantly damaged by reactive oxygen species (ROS) and reactive nitrogen species (RNS) directly and also by products of lipid peroxidation (LPO), which form exocyclic adducts to DNA bases. A wide variety of oxidatively-generated DNA lesions are present in living cells. 8-oxoguanine (8-oxoGua) is one of the best known DNA lesions due to its mutagenic properties. Among LPO-derived DNA base modifications the most intensively studied are ethenoadenine and ethenocytosine, highly miscoding DNA lesions considered as markers of oxidative stress and promutagenic DNA damage. Although at present it is impossible to directly answer the question concerning involvement of oxidatively damaged DNA in cancer etiology, it is likely that oxidatively modified DNA bases may serve as a source of mutations that initiate carcinogenesis and are involved in aging (i.e. they may be causal factors responsible for these processes). To counteract the deleterious effect of oxidatively damaged DNA, all organisms have developed several DNA repair mechanisms. The efficiency of oxidatively damaged DNA repair was frequently found to be decreased in cancer patients. The present work reviews the basis for the biological significance of DNA damage, particularly effects of 8-oxoGua and ethenoadduct occurrence in DNA in the aspect of cancer development, drawing attention to the multiplicity of proteins with repair activities. PMID:20589166

Protective effect of hydroxytyrosol and its metabolite homovanillic alcohol on H(2)O(2) induced lipid peroxidation in renal tubular epithelial cells.

PubMed

Deiana, Monica; Incani, Alessandra; Rosa, Antonella; Corona, Giulia; Atzeri, Angela; Loru, Debora; Paola Melis, M; Assunta Dessì, M

2008-09-01

We investigated the capacity of hydroxytyrosol (HT), 3,4-dihydroxyphenylethanol, and homovanillic alcohol (HVA), 4-hydroxy-3-methoxy-phenylethanol, to inhibit H(2)O(2) induced oxidative damage in LLC-PK1, a porcine kidney epithelial cell line, studying the effect of H(2)O(2) on specific cell membrane lipid targets, unsaturated fatty acids and cholesterol. Exposure to H(2)O(2) induced a significant increase of the level of MDA together with a disruption of the membrane structure, with the loss of unsaturated fatty acids, cholesterol and alpha-tocopherol, and the formation of fatty acids hydroperoxides and 7-ketocholesterol. Pretreatment with HT protected renal cells from oxidative damage: the level of membrane lipids was preserved and there was no significant detection of oxidation products. HVA exerted a comparable activity, thus both HT and HVA were able to prevent in renal cells the lipid peroxidation process that plays a central role in tubular cell injury.

Ceruloplasmin copper induces oxidant damage by a redox process utilizing cell-derived superoxide as reductant

NASA Technical Reports Server (NTRS)

Mukhopadhyay, C. K.; Fox, P. L.

1998-01-01

Oxidative damage by transition metals bound to proteins may be an important pathogenic mechanism. Ceruloplasmin (Cp) is a Cu-containing plasma protein thought to be involved in oxidative modification of lipoproteins. We have previously shown that Cp increased cell-mediated low-density lipoprotein (LDL) oxidation by a process requiring cell-derived superoxide, but the underlying chemical mechanism(s) is (are) unknown. We now show that superoxide reduction of Cp Cu is a critical reaction in cellular LDL oxidation. By bathocuproine disulfonate (BCS) binding and by superoxide utilization, we showed that exogenous superoxide reduces a single Cp Cu atom, the same Cu required for LDL oxidation. The Cu atom remained bound to Cp during the redox cycle. Three avenues of evidence showed that vascular cells reduce Cp Cu by a superoxide-dependent process. The 2-fold higher rate of Cp Cu reduction by smooth muscle cells (SMC) compared to endothelial cells (EC) was consistent with their relative rates of superoxide release. Furthermore, Cp Cu reduction by cells was blocked by Cu,Zn superoxide dismutase (SOD1). Finally, the level of superoxide produced by EC and SMC was sufficient to cause the amount of Cu reduction observed. An important role of Cp Cu reduction in LDL oxidation was suggested by results showing that SOD1 inhibited Cp Cu reduction and LDL oxidation by SMC with equal potency, while tumor necrosis factor-alpha stimulated both processes. In summary, these results show that superoxide is a critical cellular reductant of divalent transition metals involved in oxidation, and that protein-bound Cu is a substrate for this reaction. The role of these mechanisms in oxidative processes in vivo has yet to be defined.

Effect of heat stress and recovery on viability, oxidative damage, and heat shock protein expression in hepatic cells of grass carp (Ctenopharyngodon idellus).

PubMed

Cui, Yanting; Liu, Bo; Xie, Jun; Xu, Pao; Habte-Tsion, H-Michael; Zhang, Yuanyuan

2014-06-01

In this study, we investigated the effects of hyperthermia and recovery on cell viability, lactate dehydrogenase (LDH) activity, superoxide dismutase (SOD) activity, malondialdehyde (MDA), total antioxidant capacity (T-AOC), and heat shock protein (HSP60, 70, and 90) mRNA expression in the hepatic cells of the grass carp, Ctenopharyngodon idellus. Triplicate groups of cultured cells were exposed to 30, 32, or 34 °C for 0.5 h and then immediately incubated at 27 °C in 5 % CO2 for 6, 12, 24, or 48 h. Hyperthermia stress greatly reduced cell viability and increased LDH release. Cell damage declined after recovery. Hyperthermia stress increased the lipid peroxide levels and reduced the antioxidant capacity (e.g., reduced SOD and T-AOC) of the cells. However, oxidative damage declined as the recovery period increased, and the levels of MDA, SOD, and T-AOC were restored. After cells were exposed to 32 °C, the expression of HSP60 after recovery for 1, 2, and 4 h (P < 0.05), the expression of HSP70 after recovery for 0.5 and 1 h (P < 0.01), and the expression of HSP90 throughout recovery were significantly higher (P < 0.01) than the prestress levels. During the recovery period, the variations in HSP gene expression reflected the transition period from a state of cellular growth to one of the cellular repairs. In conclusion, hyperthermia depresses cell viability, induces oxidative damage, and increases HSP expression, which plays an important role during hyperthermic stress in grass carp hepatic cells.

Cells-nano interactions and molecular toxicity after delayed hypersensitivity, in guinea pigs on exposure to hydroxyapatite nanoparticles.

PubMed

Geetha, C S; Remya, N S; Leji, K B; Syama, S; Reshma, S C; Sreekanth, P J; Varma, H K; Mohanan, P V

2013-12-01

The aim of the study was to evaluate the cells-nanoparticle interactions and molecular toxicity after delayed hypersensitivity in Guinea pigs, exposed to hydroxyapatite nanoparticles (HANP). The study focuses on synthesizing and characterizing HANPs and gaining an insight into the cytotoxicity, molecular toxicity, hypersensitivity and oxidative stress caused by them in vitro and in vivo. HANP was synthesized by chemical method and characterized by standard methods. Cytotoxicity was assessed on L929 cells by MTT assay and in vitro studies were carried out on rat liver homogenate. In vivo study was carried out by topical exposure of Guinea pigs with HANP, repeatedly, and evaluating the skin sensitization potential, blood parameters, oxidative stress in liver and brain and DNA damage (8-hydroxyl-2-deoxyguanosine: 8-OHdG) in liver. The results of the study indicated that there was no cytotoxicity (up to 600μg/mL) and oxidative damage (up to 100μg/mL), when exposed to HANPs. It was also evident that, there was no skin sensitization and oxidative damage when HANP were exposed to Guinea pigs. Copyright © 2013 Elsevier B.V. All rights reserved.

Role of Mitochondrial Oxidative Stress in Spaceflight-Induced Tissue Degeneration

NASA Technical Reports Server (NTRS)

Torres, Samantha M.; Schreurs, Ann-Sofie; Truong, Tiffany A.; Tahimic, Candice; Globus, Ruth

2017-01-01

Microgravity and ionizing radiation in the spaceflight environment poses multiple challenges to homeostasis and may contribute to cellular stress. Effects may include increased generation of reactive oxygen species (ROS), DNA damage and repair error, cell cycle arrest, cell senescence or death. Our central hypothesis is that prolonged exposure to the spaceflight environment leads to the excess production of ROS and oxidative damage, culminating in accelerated tissue degeneration. The main goal of this project is to determine the importance of cellular redox defense for physiological adaptations and tissue degeneration in the space environment.

Water-soluble fractions from defatted sesame seeds protect human neuroblast cells against peroxyl radicals and hydrogen peroxide-induced oxidative stress.

PubMed

Ben Othman, Sana; Katsuno, Nakako; Kitayama, Akemi; Fujimura, Makoto; Kitaguchi, Kohji; Yabe, Tomio

2016-09-01

Oxidative stress is involved in the development of aging-related diseases, such as neurodegenerative diseases. Dietary antioxidants that can protect neuronal cells from oxidative damage play an important role in preventing such diseases. Previously, we reported that water-soluble fractions purified from defatted sesame seed flour exhibit good antioxidant activity in vitro. In the present study, we investigated the protective effects of white and gold sesame seed water-soluble fractions (WS-wsf and GS-wsf, respectively) against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H2O2) induced oxidative stress in human neuroblast SH-SY5Y cells. Pretreatment with WS-wsf and GS-wsf did not protect cells against AAPH-induced cytotoxicity, while simultaneous co-treatment with AAPH significantly improved cell viability and inhibited membrane lipid peroxidation. These results suggest that WS-wsf and GS-wsf protect cells from AAPH-induced extracellular oxidative damage via direct scavenging of peroxyl radicals. When oxidative stress was induced by H2O2, pretreatment WS-wsf and GS-wsf significantly enhanced cell viability. These results suggest that in addition to radical scavenging, WS-wsf and GS-wsf enhance cellular resistance to intracellular oxidative stress by activation of the Nrf-2/ARE pathway as confirmed by the increased Nrf2 protein level in the nucleus and increased heme oxygenase 1 (HO-1) mRNA expression. The roles of ferulic and vanillic acids as bioactive antioxidants in these fractions were also confirmed. In conclusion, our results indicated that WS-wsf and GS-wsf, which showed antioxidant activity in vitro, are also efficient antioxidants in a cell system protecting SH-SY5Y cells against both extracellular and intracellular oxidative stress.

Exogenous calcium improves viability of biocontrol yeasts under heat stress by reducing ROS accumulation and oxidative damage of cellular protein.

PubMed

An, Bang; Li, Boqiang; Qin, Guozheng; Tian, Shiping

2012-08-01

In this article, we investigated the effect of exogenous calcium on improving viability of Debaryomyces hansenii and Pichia membranaefaciens under heat stress, and evaluated the role of calcium in reducing oxidant damage of proteins in the yeast cells. The results indicated that high concentration of exogenous calcium in culture medium was beneficial for enhancing the tolerance of the biocontrol yeasts to heat stress. The possible mechanism of calcium improving the viability of yeasts was attributed to enhancement of antioxidant enzyme activities, decrease in ROS accumulation and reduction of oxidative damage of intracellular protein in yeast cells under heat stress. D. hansenii is more sensitive to calcium as compared to P. membranaefaciens. Our results suggest that application of exogenous calcium combined with biocontrol yeasts is a practical approach for the control of postharvest disease in fruit.

Environmental factors and unhealthy lifestyle influence oxidative stress in humans--an overview.

PubMed

Aseervatham, G Smilin Bell; Sivasudha, T; Jeyadevi, R; Arul Ananth, D

2013-07-01

Oxygen is the most essential molecule for life; since it is a strong oxidizing agent, it can aggravate the damage within the cell by a series of oxidative events including the generation of free radicals. Antioxidative agents are the only defense mechanism to neutralize these free radicals. Free radicals are not only generated internally in our body system but also trough external sources like environmental pollution, toxic metals, cigarette smoke, pesticides, etc., which add damage to our body system. Inhaling these toxic chemicals in the environment has become unavoidable in modern civilization. Antioxidants of plant origin with free radical scavenging properties could have great importance as therapeutic agents in several diseases caused by environmental pollution. This review summarizes the generation of reactive oxygen species and damage to cells by exposure to external factors, unhealthy lifestyle, and role of herbal plants in scavenging these reactive oxygen species.

Reproductive Benefit of Oxidative Damage: An Oxidative Stress “Malevolence”?

PubMed Central

Poljsak, B.; Milisav, I.; Lampe, T.; Ostan, I.

2011-01-01

High levels of reactive oxygen species (ROS) compared to antioxidant defenses are considered to play a major role in diverse chronic age-related diseases and aging. Here we present an attempt to synthesize information about proximate oxidative processes in aging (relevant to free radical or oxidative damage hypotheses of aging) with an evolutionary scenario (credited here to Dawkins hypotheses) involving tradeoffs between the costs and benefits of oxidative stress to reproducing organisms. Oxidative stress may be considered a biological imperfection; therefore, the Dawkins' theory of imperfect adaptation of beings to environment was applied to the role of oxidative stress in processes like famine and infectious diseases and their consequences at the molecular level such as mutations and cell signaling. Arguments are presented that oxidative damage is not necessarily an evolutionary mistake but may be beneficial for reproduction; this may prevail over its harmfulness to health and longevity in evolution. Thus, Dawkins' principle of biological “malevolence” may be an additional biological paradigm for explaining the consequences of oxidative stress. PMID:21969876

Multiple protective effect of peptides released from Olea europaea and Prunus persica seeds against oxidative damage and cancer cell proliferation.

PubMed

Hernández-Corroto, Ester; Marina, María Luisa; García, María Concepción

2018-04-01

The long exposition to reactive species results in oxidative stress which has been related with the development of cancer and other serious diseases. Olea europaea and Prunus persica seeds present a high protein content and preliminary results demonstrated their high potency to obtain bioactive peptides. The protective effect against oxidative damage exerted by peptides released from Olea europaea and Prunus persica seeds has been evaluated in this work. Seed hydrolysates showed protection against oxidation through four different mechanisms: inhibition of the formation of hydroxyl radicals, scavenging of free radicals, reduction of oxidizing compounds, and inhibition of lipid peroxidation. Moreover, seed hydrolysates also reduced the oxidative stress induced by an oxidizing agent on human cancer cells. Despite protection evaluated by individual mechanisms seemed to be significantly affected by the seed genotype, overall protection of seed hydrolysates was not so different. Seeds hydrolysates were not cytotoxic on normal cells but they demonstrated antiproliferative effect on human cancer cells (HeLa, PC-3, and HT-29). Peptides in all seed hydrolysates were sequenced by RP-HPLC-ESI-Q-TOF. Eighteen common peptides were observed among olive seed hydrolysates while a wider variability was observed among Prunus seed hydrolysates. Copyright © 2018 Elsevier Ltd. All rights reserved.

Acute and long-term in vitro effects of zinc oxide nanoparticles.

PubMed

Annangi, Balasubramanyam; Rubio, Laura; Alaraby, Mohamed; Bach, Jordi; Marcos, Ricard; Hernández, Alba

2016-09-01

Since most of the toxic studies of zinc oxide nanoparticles (ZnO NPs) focused on acute and high-dose exposure conditions, the aim of the present study was to fill the existing knowledge gap of long-term effects of ZnO NPs at sub-toxic doses. To overcome this point, we have evaluated the toxic, genotoxic, and carcinogenic effects of ZnO NPs under long-term treatments (12 weeks), using a sub-toxic dose (1 µg/mL) according to acute 48-h exposure. Preliminarily, oxidative stress and genotoxic/oxidative DNA damage were determined under acute exposure and high-dose conditions. To determine the role of oxidative DNA damage, a wild-type mouse embryonic fibroblast (MEF Ogg1 (+/+)) and its isogenic 8-oxo-guanine DNA glycosylase 1 (Ogg1) knockout partner (MEF Ogg1 (-/-)) cell lines were used. Although short-term exposure (24-h) experiments demonstrated that ZnO NPs were able to induce ROS, genotoxicity, and oxidative DNA damage in both cell lines, no effects were obtained under long-term exposure scenario. Thus, 1 µg/mL exposure over 12 weeks was unable to induce genotoxicity as well as cellular transformation in both cell types, as indicated by the lack of observed morphological cell changes, variations in the secretion of matrix metalloproteinases, and anchorage-independent cell growth ability, regarded as cancer-like phenotypic hallmarks. Our results indicate that short-term effects of ZnO NP exposure are not replicated under long-term and sub-toxic dose conditions. All together, the lack of genotoxic/carcinogenic effects after chronic treatments seem to indicate a reduced risk associated with ZnO NP exposure.

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

PubMed

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 that induced oxidative stress affecting key proteins involved in cell cycle arrest at G1/S and triggering apoptosis. Finally, the overall data from this study are well in line with the traditional claims for the antitumor effect of Piper nigrum fruits. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Ischemia-induced endothelial cell swelling and mitochondrial dysfunction are attenuated by dietary polyphenols in vitro

USDA-ARS?s Scientific Manuscript database

Polyphenols possess anti-oxidant and anti-inflammatory properties. Oxidative stress (OS) and inflammation have been implicated in the pathogenesis of cytotoxic brain edema in cerebral ischemia. In addition, OS and pro-inflammatory cytokines also damage the endothelial cells and the neurovascular uni...

Consequences of acute oxidative stress in Leishmania amazonensis: From telomere shortening to the selection of the fittest parasites.

PubMed

da Silva, Marcelo Santos; Segatto, Marcela; Pavani, Raphael Souza; Gutierrez-Rodrigues, Fernanda; Bispo, Vanderson da Silva; de Medeiros, Marisa Helena Gennari; Calado, Rodrigo Tocantins; Elias, Maria Carolina; Cano, Maria Isabel Nogueira

2017-01-01

Leishmaniasis is a spectrum of diseases caused by parasites of the genus Leishmania that affects millions of people around the world. During infection, the parasites use different strategies to survive the host's defenses, including overcoming exposure to reactive oxidant species (ROS), responsible for causing damage to lipids, proteins and DNA. This damage especially affects telomeres, which frequently results in genome instability, senescence and cell death. Telomeres are the physical ends of the chromosomes composed of repetitive DNA coupled with proteins, whose function is to protect the chromosomes termini and avoid end-fusion and nucleolytic degradation. In this work, we induced acute oxidative stress in promastigote forms of Leishmania amazonensis by treating parasites with 2mM hydrogen peroxide (H 2 O 2 ) for 1h, which was able to increase intracellular ROS levels. In addition, oxidative stress induced DNA damage, as confirmed by 8-oxodGuo quantification and TUNEL assays and the dissociation of LaRPA-1 from the 3' G-overhang, leading to telomere shortening. Moreover, LaRPA-1 was observed to interact with newly formed C-rich single-stranded telomeric DNA, probably as a consequence of the DNA damage response. Nonetheless, acute oxidative stress caused the death of some of the L. amazonensis population and induced cell cycle arrest at the G2/M phase in survivor parasites, which were able to continue proliferating and replicating DNA and became more resistant to oxidative stress. Taken together, these results suggest that adaptation occurs through the selection of the fittest parasites in terms of repairing oxidative DNA damage at telomeres and maintaining genome stability in a stressful environment. Copyright © 2016 Elsevier B.V. All rights reserved.

A mosquito 2-Cys peroxiredoxin protects against nitrosative and oxidative stresses associated with malaria parasite infection

PubMed Central

Peterson, Tina M.L.; Luckhart, Shirley

2008-01-01

Malaria parasite infection in anopheline mosquitoes induces nitrosative and oxidative stresses that limit parasite development, but also damage mosquito tissues in proximity to the response. Based on these observations, we proposed that cellular defenses in the mosquito may be induced to minimize self-damage. Specifically, we hypothesized that peroxiredoxins (Prxs), enzymes known to detoxify reactive oxygen species (ROS) and reactive nitrogen oxide species (RNOS), protect mosquito cells. We identified an Anopheles stephensi 2-Cys Prx ortholog of Drosophila melanogaster Prx-4783, which protects fly cells against oxidative stresses. To assess function, AsPrx-4783 was overexpressed in D. melanogaster (S2) and in A. stephensi (MSQ43) cells and silenced in MSQ43 cells with RNA interference before treatment with various ROS and RNOS. Our data revealed that AsPrx-4783 and DmPrx-4783 differ in host cell protection and that AsPrx-4783 protects A. stephensi cells against stresses that are relevant to malaria parasite infection in vivo, namely nitric oxide (NO), hydrogen peroxide, nitroxyl, and peroxynitrite. Further, AsPrx-4783 expression is induced in the mosquito midgut by parasite infection at times associated with peak nitrosative and oxidative stresses. Hence, whereas the NO-mediated defense response is toxic to both host and parasite, AsPrx-4783 may shift the balance in favor of the mosquito. PMID:16540402

Aldehyde dehydrogenase 2 protects human umbilical vein endothelial cells against oxidative damage and increases endothelial nitric oxide production to reverse nitroglycerin tolerance.

PubMed

Hu, X Y; Fang, Q; Ma, D; Jiang, L; Yang, Y; Sun, J; Yang, C; Wang, J S

2016-06-10

Medical nitroglycerin (glyceryl trinitrate, GTN) use is limited principally by tolerance typified by a decrease in nitric oxide (NO) produced by biotransformation. Such tolerance may lead to endothelial dysfunction by inducing oxidative stress. In vivo studies have demonstrated that aldehyde dehydrogenase 2 (ALDH2) plays important roles in GTN biotransformation and tolerance. Thus, modification of ALDH2 expression represents a potentially effective strategy to prevent and reverse GTN tolerance and endothelial dysfunction. In this study, a eukaryotic expression vector containing the ALDH2 gene was introduced into human umbilical vein endothelial cells (HUVECs) by liposome-mediated transfection. An indirect immunofluorescence assay showed that ALDH2 expression increased 24 h after transfection. Moreover, real-time polymerase chain reaction and western blotting revealed significantly higher ALDH2 mRNA and protein expression in the gene-transfected group than in the two control groups. GTN tolerance was induced by treating HUVECs with 10 mM GTN for 16 h + 10 min, which significantly decreased NO levels in control cells, but not in those transfected with ALDH2. Overexpression of ALDH2 increased cell survival against GTN-induced cytotoxicity and conferred protection from oxidative damage resulting from nitrate tolerance, accompanied by decreased production of intracellular reactive oxygen species and reduced expression of heme oxygenase 1. Furthermore, ALDH2 overexpression promoted Akt phosphorylation under GTN tolerance conditions. ALDH2 gene transfection can reverse and prevent tolerance to GTN through its bioactivation and protect against oxidative damage, preventing the development of endothelial dysfunction.

Protective effect of grape seed extracts on human lymphocytes: a preliminary study.

PubMed

Szeto, Yim Tong; Lee, Kit Yee; Kalle, Wouter; Pak, Sok Cheon

2013-03-01

Grape seed extracts (GSEs) possess a broad spectrum of antioxidative properties that protects various cells from free radicals and oxidative stress. In this study, the genoprotective effect of GSE on human lymphocytic DNA was studied using standard and lysed cell comet assays. Lymphocytes from 5 healthy subjects were pretreated with GSE in different concentrations. The standard and lysed cell comet assays were performed on treated, untreated, challenged, and unchallenged cells in parallel. Cells were then subjected to an oxidant challenge induced with 5-min exposures to hydrogen peroxide. In the standard comet assay, GSE significantly diminished hydrogen-peroxide-induced DNA damage in a dose-dependent manner. In the lysed cell assay, however, the antioxidant effect was diminished at a higher GSE concentration. Data indicate that the cell membrane might play a role in limiting cellular access to antioxidants, which directly affects the genoprotective or potential pro-oxidant effect of antioxidants on human DNA. Using both standard and lysed cell comet assays in parallel could be a useful way to elucidate the mechanism of protection or damage by antioxidants.

Interactions between muscle and the immune system during modified musculoskeletal loading

NASA Technical Reports Server (NTRS)

Tidball, James G.

2002-01-01

Interactions between the immune system and skeletal muscle may play a significant role in modulating the course of muscle injury and repair after modified musculoskeletal loading. Current evidence indicates that activation of the complement system is an early event during modified loading, which then leads to inflammatory cell invasion. However, the functions of those inflammatory cells are complex and they seem to be capable of promoting additional injury and repair. Recent findings implicate an early invading neutrophil population in increasing muscle damage that is detected by the presence of muscle membrane lesions. Macrophages that invade subsequently serve to remove cellular debris, and seem to promote repair. However, macrophages also have the ability to increase damage in muscle in which there is an impaired capacity to generate nitric oxide. In vivo and in vitro evidence indicates that muscle-derived nitric oxide can serve an important role in protecting muscle from membrane damage by invading inflammatory cells. Collectively, these findings indicate that the dynamic balance between inflammatory cells, the complement system, and muscle-derived free radicals can play important roles in the secondary damage of muscle during modified musculoskeletal loading.

Protein methylation as a marker of aspartate damage in glucose-6-phosphate dehydrogenase-deficient erythrocytes: role of oxidative stress.

PubMed

Ingrosso, Diego; Cimmino, Amelia; D'Angelo, Stefania; Alfinito, Fiorella; Zappia, Vincenzo; Galletti, Patrizia

2002-04-01

The 'Mediterranean' variant of glucose-6-phosphate dehydrogenase (G6PD) deficiency is due to the C563CT point mutation, leading to replacement of Ser with Phe at position 188, resulting in acute haemolysis triggered by oxidants. Previous work has shown increased formation of altered aspartate residues in membrane proteins during cell ageing and in response to oxidative stress in normal erythrocytes. These abnormal residues are specifically recognized by the repair enzyme L-isoaspartate (d-aspartate) protein O-methyltransferase (PCMT; EC 2.1.1.77). The aim of this work was to study the possible involvement of protein aspartate damage in the mechanism linking the G6PD defect and erythrocyte injury, through oxidative stress. Patients affected by G6PD deficiency (Mediterranean variant) were selected. In situ methylation assays were performed by incubating intact erythrocytes in the presence of methyl-labelled methionine. Altered aspartate residues were detected in membrane proteins by methyl ester quantification. We present here evidence that, in G6PD-deficient erythrocytes, damaged residues are significantly increased in membrane proteins, in parallel with the decay of pyruvate kinase activity, used as a cell age marker. Erythrocytes from patients were subjected to oxidative stress in vitro, by treatment with t-butylhydroperoxide, monitored by a rise in concentration of both methaemoglobin and thiobarbituric acid-reactive substances. L-Isoaspartate residues increased dramatically in G6PD-deficient erythrocytes in response to such treatment, compared with baseline conditions. The increased susceptibility of G6PD-deficient erythrocytes to membrane protein aspartate damage in response to oxidative stress suggests the involvement of protein deamidation/isomerization in the mechanisms of cell injury and haemolysis.

Aldosterone Activates Transcription Factor Nrf2 in Kidney Cells Both In Vitro and In Vivo

PubMed Central

Oteiza, Patricia I.; Link, Samuel; Hey, Valentin; Stopper, Helga; Schupp, Nicole

2014-01-01

Abstract Aims: An increased kidney cancer risk was found in hypertensive patients, who frequently exhibit hyperaldosteronism, known to contribute to kidney injury, with oxidative stress playing an important role. The capacity of kidney cells to up-regulate transcription factor nuclear factor-erythroid-2-related factor 2 (Nrf2), a key regulator of the cellular antioxidative defense, as a prevention of aldosterone-induced oxidative damage was investigated both in vitro and in vivo. Results: Aldosterone activated Nrf2 and increased the expression of enzymes involved in glutathione (GSH) synthesis and detoxification. This activation depended on the mineralocorticoid receptor (MR) and oxidative stress. In vitro, Nrf2 activation, GSH amounts, and target gene levels decreased after 24 h, while oxidant levels remained high. Nrf2 activation could not protect cells against oxidative DNA damage, as aldosterone-induced double-strand breaks and 7,8-dihydro-8-oxo-guanine (8-oxodG) lesions steadily rose. The Nrf2 activator sulforaphane enhanced the Nrf2 response both in vitro and in vivo, thereby preventing aldosterone-induced DNA damage. In vivo, Nrf2 activation further had beneficial effects on the aldosterone-caused blood pressure increase and loss of kidney function. Innovation: This is the first study showing the activation of Nrf2 by aldosterone. Moreover, the results identify sulforaphane as a substance that is capable of preventing aldosterone-induced damage both in vivo and in vitro. Conclusion: Aldosterone-induced Nrf2 adaptive response cannot neutralize oxidative actions of chronically increased aldosterone, which, therefore could be causally involved in the increased cancer incidence of hypertensive individuals. Enhancing the cellular antioxidative defense with sulforaphane might exhibit beneficial effects. Antioxid. Redox Signal. 21, 2126–2142. PMID:24512358

Changes in oxidative stress parameters in relation to age, growth and reproduction in the short-lived catarina scallop Argopecten ventricosus reared in its natural environment.

PubMed

Guerra, C; Zenteno-Savín, T; Maeda-Martínez, A N; Philipp, E E R; Abele, D

2012-08-01

Increase in oxidative damage and decrease in cellular maintenance is often associated with aging, but, in marine ectotherms, both processes are also strongly influenced by somatic growth, maturation and reproduction. In this study, we used a single cohort of the short-lived catarina scallop Argopecten ventricosus, to investigate the effects of somatic growth, reproduction and aging on oxidative damage parameters (protein carbonyls, TBARS and lipofuscin) and cellular maintenance mechanisms (antioxidant activity and apoptosis) in scallops, caged in their natural environment. The concentrations of protein carbonyls and TBARS increased steeply during the early period of fast growth and during reproduction in one-year-old scallops. However, oxidative damage was transient, and apoptotic cell death played a pivotal role in eliminating damage in gill, mantle and muscle tissues of young scallops. Animals were able to reproduce again in the second year, but the reduced intensity of apoptosis impaired subsequent removal of damaged cells. In late survivors low antioxidant capacity and apoptotic activity together with a fast accumulation of the age pigment lipofuscin was observed. Rates of oxygen consumption and oxidative stress markers were strongly dependent on somatic growth and reproductive state but not on temperature. Compared to longer-lived bivalves, A. ventricosus seems more susceptible to oxidative stress with higher tissue-specific protein carbonyl levels and fast accumulation of lipofuscin in animals surviving the second spawning. Superoxide dismutase activity and apoptotic cell death intensity were however higher in this short-lived scallop than in longer-lived bivalves. The life strategy of this short-lived and intensely predated scallop supports rapid somatic growth and fitness as well as early maturation at young age at the cost of fast cellular degradation in second year scallops. Copyright © 2012 Elsevier Inc. All rights reserved.

Comparative analysis of the relative potential of silver, Zinc-oxide and titanium-dioxide nanoparticles against UVB-induced DNA damage for the prevention of skin carcinogenesis.

PubMed

Tyagi, Nikhil; Srivastava, Sanjeev K; Arora, Sumit; Omar, Yousef; Ijaz, Zohaib Mohammad; Al-Ghadhban, Ahmed; Deshmukh, Sachin K; Carter, James E; Singh, Ajay P; Singh, Seema

2016-12-01

Sunscreen formulations containing UVB filters, such as Zinc-oxide (ZnO) and titanium-dioxide (TiO 2 ) nanoparticles (NPs) have been developed to limit the exposure of human skin to UV-radiations. Unfortunately, these UVB protective agents have failed in controlling the skin cancer incidence. We recently demonstrated that silver nanoparticles (Ag-NPs) could serve as novel protective agents against UVB-radiations. Here our goal was to perform comparative analysis of direct and indirect UVB-protection efficacy of ZnO-, TiO 2 - and Ag-NPs. Sun-protection-factor calculated based on their UVB-reflective/absorption abilities was the highest for TiO 2 -NPs followed by Ag- and ZnO-NPs. This was further confirmed by studying indirect protection of UVB radiation-induced death of HaCaT cells. However, only Ag-NPs were active in protecting HaCaT cells against direct UVB-induced DNA-damage by repairing bulky-DNA lesions through nucleotide-excision-repair mechanism. Moreover, Ag-NPs were also effective in protecting HaCaT cells from UVB-induced oxidative DNA damage by enhancing SOD/CAT/GPx activity. In contrast, ZnO- and TiO 2 -NPs not only failed in providing any direct protection from DNA-damage, but rather enhanced oxidative DNA-damage by increasing ROS production. Together, these findings raise concerns about safety of ZnO- and TiO 2 -NPs and establish superior protective efficacy of Ag-NPs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Oxidative stress and mitochondrial adaptive shift during pituitary tumoral growth.

PubMed

Sabatino, Maria Eugenia; Grondona, Ezequiel; Sosa, Liliana D V; Mongi Bragato, Bethania; Carreño, Lucia; Juarez, Virginia; da Silva, Rodrigo A; Remor, Aline; de Bortoli, Lucila; de Paula Martins, Roberta; Pérez, Pablo A; Petiti, Juan Pablo; Gutiérrez, Silvina; Torres, Alicia I; Latini, Alexandra; De Paul, Ana L

2018-05-20

The cellular transformation of normal functional cells to neoplastic ones implies alterations in the cellular metabolism and mitochondrial function in order to provide the bioenergetics and growth requirements for tumour growth progression. Currently, the mitochondrial physiology and dynamic shift during pituitary tumour development are not well understood. Pituitary tumours present endocrine neoplastic benign growth which, in previous reports, we had shown that in addition to increased proliferation, these tumours were also characterized by cellular senescence signs with no indication of apoptosis. Here, we show clear evidence of oxidative stress in pituitary cells, accompanied by bigger and round mitochondria during tumour development, associated with augmented biogenesis and an increased fusion process. An activation of the Nrf2 stress response pathway together with the attenuation of the oxidative damage signs occurring during tumour development were also observed which will probably provide survival advantages to the pituitary cells. These neoplasms also presented a progressive increase in lactate production, suggesting a metabolic shift towards glycolysis metabolism. These findings might imply an oxidative stress state that could impact on the pathogenesis of pituitary tumours. These data may also reflect that pituitary cells can modulate their metabolism to adapt to different energy requirements and signalling events in a pathophysiological situation to obtain protection from damage and enhance their survival chances. Thus, we suggest that mitochondria function, oxidative stress or damage might play a critical role in pituitary tumour progression. Copyright © 2018 Elsevier Inc. All rights reserved.

Targeting an antioxidant to mitochondria decreases cardiac ischemia-reperfusion injury.

PubMed

Adlam, Victoria J; Harrison, Joanne C; Porteous, Carolyn M; James, Andrew M; Smith, Robin A J; Murphy, Michael P; Sammut, Ivan A

2005-07-01

Mitochondrial oxidative damage contributes to a wide range of pathologies, including cardiovascular disorders and neurodegenerative diseases. Therefore, protecting mitochondria from oxidative damage should be an effective therapeutic strategy. However, conventional antioxidants have limited efficacy due to the difficulty of delivering them to mitochondria in situ. To overcome this problem, we developed mitochondria-targeted antioxidants, typified by MitoQ, which comprises a lipophilic triphenylphosphonium (TPP) cation covalently attached to a ubiquinol antioxidant. Driven by the large mitochondrial membrane potential, the TPP cation concentrates MitoQ several hundred-fold within mitochondria, selectively preventing mitochondrial oxidative damage. To test whether MitoQ was active in vivo, we chose a clinically relevant form of mitochondrial oxidative damage: cardiac ischemia-reperfusion injury. Feeding MitoQ to rats significantly decreased heart dysfunction, cell death, and mitochondrial damage after ischemia-reperfusion. This protection was due to the antioxidant activity of MitoQ within mitochondria, as an untargeted antioxidant was ineffective and accumulation of the TPP cation alone gave no protection. Therefore, targeting antioxidants to mitochondria in vivo is a promising new therapeutic strategy in the wide range of human diseases such as Parkinson's disease, diabetes, and Friedreich's ataxia where mitochondrial oxidative damage underlies the pathology.

Cell injury and repair resulting from sleep loss and sleep recovery in laboratory rats.

PubMed

Everson, Carol A; Henchen, Christopher J; Szabo, Aniko; Hogg, Neil

2014-12-01

Increased cell injury would provide the type of change in constitution that would underlie sleep disruption as a risk factor for multiple diseases. The current study was undertaken to investigate cell injury and altered cell fate as consequences of sleep deprivation, which were predicted from systemic clues. Partial (35% sleep reduction) and total sleep deprivation were produced in rats for 10 days, which was tolerated and without overtly deteriorated health. Recovery rats were similarly sleep deprived for 10 days, then allowed undisturbed sleep for 2 days. The plasma, liver, lung, intestine, heart, and spleen were analyzed and compared to control values for damage to DNA, proteins, and lipids; apoptotic cell signaling and death; cell proliferation; and concentrations of glutathione peroxidase and catalase. Oxidative DNA damage in totally sleep deprived rats was 139% of control values, with organ-specific effects in the liver (247%), lung (166%), and small intestine (145%). Overall and organ-specific DNA damage was also increased in partially sleep deprived rats. In the intestinal epithelium, total sleep deprivation resulted in 5.3-fold increases in dying cells and 1.5-fold increases in proliferating cells, compared with control. Recovery sleep restored the balance between DNA damage and repair, and resulted in normal or below-normal metabolic burdens and oxidative damage. These findings provide physical evidence that sleep loss causes cell damage, and in a manner expected to predispose to replication errors and metabolic abnormalities; thereby providing linkage between sleep loss and disease risk observed in epidemiological findings. Properties of recovery sleep include biochemical and molecular events that restore balance and decrease cell injury. © 2014 Associated Professional Sleep Societies, LLC.

Beta-carotene and lutein protect HepG2 human liver cells against oxidant-induced damage.

PubMed

Martin, K R; Failla, M L; Smith, J C

1996-09-01

Numerous epidemiological studies support a strong inverse relationship between consumption of carotenoid-rich fruits and vegetables and the incidence of some degenerative diseases. One proposed mechanism of protection by carotenoids centers on their putative antioxidant activity, although direct evidence in support of this contention is limited at the cellular level. The antioxidant potential of beta-carotene (BC) and lutein (LUT), carotenoids with or without provitamin A activity, respectively, was evaluated using the human liver cell line HepG2. Pilot studies showed that a 90-min exposure of confluent cultures to 500 mumol/L tert-butylhydroperoxide (TBHP) at 37 degrees C significantly (P < 0.05) increased lipid peroxidation and cellular leakage of lactate dehydrogenase (LDH), and decreased the uptake of 3H-alpha-aminoisobutyric acid and 3H-2-deoxyglucose. Protein synthesis, mitochondrial activity and glucose oxidation were not affected by TBHP treatment, suggesting that the plasma membrane was the primary site of TBHP-induced damage. Overnight incubation of cultures with > or = 1 mumol/L dl-alpha-tocopherol protected cells against oxidant-induced changes. In parallel studies, overnight incubation of HepG2 in medium containing micelles with either BC or LUT (final concentrations of 1.1 and 10.9 mumol/L, respectively), the cell content of the carotenoids increased from < 0.04 to 0.32 and 3.39 nmol/mg protein, respectively. Carotenoid-loaded cells were partially or completely protected against oxidant-induced changes in lipid peroxidation, LDH release and amino acid and deoxyglucose transport. These data demonstrate that BC and LUT or their metabolites protect HepG2 cells against oxidant-induced damage and that the protective effect is independent of provitamin A activity.

Allicin enhances the oxidative damage effect of amphotericin B against Candida albicans.

PubMed

An, MaoMao; Shen, Hui; Cao, YongBing; Zhang, JunDong; Cai, Yun; Wang, Rui; Jiang, YuanYing

2009-03-01

Amphotericin B (AmB) is the gold standard of antifungal treatment for the most severe invasive mycoses. In addition to the interaction of AmB with ergosterol in the fungi cell membrane, several studies have demonstrated oxidative damage involved in the fungicidal activity of AmB. In this study, allicin, an allyl sulphur compound from garlic, was shown to enhance significantly the effect of AmB against Candida albicans in vitro and in vivo, although allicin did not exert a fungicidal effect. Further study first demonstrated that allicin-mediated oxidative damage, such as phospholipid peroxidation in the plasma membrane, via influencing the defence of C. albicans against oxidative damage may be the cause of the synergistic interaction between allicin and AmB. We envision that a combination of AmB with allicin may prove to be a promising strategy for the therapy of disseminated candidiasis.

Wavelength dependence of biological damage induced by UV radiation on bacteria.

PubMed

Santos, Ana L; Oliveira, Vanessa; Baptista, Inês; Henriques, Isabel; Gomes, Newton C M; Almeida, Adelaide; Correia, António; Cunha, Ângela

2013-01-01

The biological effects of UV radiation of different wavelengths (UVA, UVB and UVC) were assessed in nine bacterial isolates displaying different UV sensitivities. Biological effects (survival and activity) and molecular markers of oxidative stress [DNA strand breakage (DSB), generation of reactive oxygen species (ROS), oxidative damage to proteins and lipids, and the activity of antioxidant enzymes catalase and superoxide dismutase] were quantified and statistically analyzed in order to identify the major determinants of cell inactivation under the different spectral regions. Survival and activity followed a clear wavelength dependence, being highest under UVA and lowest under UVC. The generation of ROS, as well as protein and lipid oxidation, followed the same pattern. DNA damage (DSB) showed the inverse trend. Multiple stepwise regression analysis revealed that survival under UVA, UVB and UVC wavelengths was best explained by DSB, oxidative damage to lipids, and intracellular ROS levels, respectively.

Electronic cigarette aerosols suppress cellular antioxidant defenses and induce significant oxidative DNA damage

PubMed Central

Ganapathy, Vengatesh; Manyanga, Jimmy; Brame, Lacy; McGuire, Dehra; Sadhasivam, Balaji; Floyd, Evan; Rubenstein, David A.; Ramachandran, Ilangovan; Wagener, Theodore

2017-01-01

Background Electronic cigarette (EC) aerosols contain unique compounds in addition to toxicants and carcinogens traditionally found in tobacco smoke. Studies are warranted to understand the public health risks of ECs. Objective The aim of this study was to determine the genotoxicity and the mechanisms induced by EC aerosol extracts on human oral and lung epithelial cells. Methods Cells were exposed to EC aerosol or mainstream smoke extracts and DNA damage was measured using the primer anchored DNA damage detection assay (q-PADDA) and 8-oxo-dG ELISA assay. Cell viability, reactive oxygen species (ROS) and total antioxidant capacity (TAC) were measured using standard methods. mRNA and protein expression were evaluated by RT-PCR and western blot, respectively. Results EC aerosol extracts induced DNA damage in a dose-dependent manner, but independently of nicotine concentration. Overall, EC aerosol extracts induced significantly less DNA damage than mainstream smoke extracts, as measured by q-PADDA. However, the levels of oxidative DNA damage, as indicated by the presence of 8-oxo-dG, a highly mutagenic DNA lesion, were similar or slightly higher after exposure to EC aerosol compared to mainstream smoke extracts. Mechanistically, while exposure to EC extracts significantly increased ROS, it decreased TAC as well as the expression of 8-oxoguanine DNA glycosylase (OGG1), an enzyme essential for the removal of oxidative DNA damage. Conclusions Exposure to EC aerosol extracts suppressed the cellular antioxidant defenses and led to significant DNA damage. These findings emphasize the urgent need to investigate the potential long-term cancer risk of exposure to EC aerosol for vapers and the general public. PMID:28542301

Alkylation Damage by Lipid Electrophiles Targets Functional Protein Systems*

PubMed Central

Codreanu, Simona G.; Ullery, Jody C.; Zhu, Jing; Tallman, Keri A.; Beavers, William N.; Porter, Ned A.; Marnett, Lawrence J.; Zhang, Bing; Liebler, Daniel C.

2014-01-01

Protein alkylation by reactive electrophiles contributes to chemical toxicities and oxidative stress, but the functional impact of alkylation damage across proteomes is poorly understood. We used Click chemistry and shotgun proteomics to profile the accumulation of proteome damage in human cells treated with lipid electrophile probes. Protein target profiles revealed three damage susceptibility classes, as well as proteins that were highly resistant to alkylation. Damage occurred selectively across functional protein interaction networks, with the most highly alkylation-susceptible proteins mapping to networks involved in cytoskeletal regulation. Proteins with lower damage susceptibility mapped to networks involved in protein synthesis and turnover and were alkylated only at electrophile concentrations that caused significant toxicity. Hierarchical susceptibility of proteome systems to alkylation may allow cells to survive sublethal damage while protecting critical cell functions. PMID:24429493

Hemin causes mitochondrial dysfunction in endothelial cells through promoting lipid peroxidation: the protective role of autophagy

PubMed Central

Higdon, Ashlee N.; Benavides, Gloria A.; Chacko, Balu K.; Ouyang, Xiaosen; Johnson, Michelle S.; Landar, Aimee; Zhang, Jianhua

2012-01-01

The hemolysis of red blood cells and muscle damage results in the release of the heme proteins myoglobin, hemoglobin, and free heme into the vasculature. The mechanisms of heme toxicity are not clear but may involve lipid peroxidation, which we hypothesized would result in mitochondrial damage in endothelial cells. To test this, we used bovine aortic endothelial cells (BAEC) in culture and exposed them to hemin. Hemin led to mitochondrial dysfunction, activation of autophagy, mitophagy, and, at high concentrations, apoptosis. To detect whether hemin induced lipid peroxidation and damaged proteins, we used derivatives of arachidonic acid tagged with biotin or Bodipy (Bt-AA, BD-AA). We found that in cells treated with hemin, Bt-AA was oxidized and formed adducts with proteins, which were inhibited by α-tocopherol. Hemin-dependent mitochondrial dysfunction was also attenuated by α-tocopherol. Protein thiol modification and carbonyl formation occurred on exposure and was not inhibited by α-tocopherol. Supporting a protective role of autophagy, the inhibitor 3-methyladenine potentiated cell death. These data demonstrate that hemin mediates cytotoxicity through a mechanism which involves protein modification by oxidized lipids and other oxidants, decreased respiratory capacity, and a protective role for the autophagic process. Attenuation of lipid peroxidation may be able to preserve mitochondrial function in the endothelium and protect cells from heme-dependent toxicity. PMID:22245770

Magnesium Supplementation Diminishes Peripheral Blood Lymphocyte DNA Oxidative Damage in Athletes and Sedentary Young Man

PubMed Central

Petrović, Jelena; Stanić, Dušanka; Dmitrašinović, Gordana; Plećaš-Solarović, Bosiljka; Ignjatović, Svetlana; Batinić, Bojan; Popović, Dejana

2016-01-01

Sedentary lifestyle is highly associated with increased risk of cardiovascular disease, obesity, and type 2 diabetes. It is known that regular physical activity has positive effects on health; however several studies have shown that acute and strenuous exercise can induce oxidative stress and lead to DNA damage. As magnesium is essential in maintaining DNA integrity, the aim of this study was to determine whether four-week-long magnesium supplementation in students with sedentary lifestyle and rugby players could prevent or diminish impairment of DNA. By using the comet assay, our study demonstrated that the number of peripheral blood lymphocytes (PBL) with basal endogenous DNA damage is significantly higher in rugby players compared to students with sedentary lifestyle. On the other hand, magnesium supplementation significantly decreased the number of cells with high DNA damage, in the presence of exogenous H2O2, in PBL from both students and rugby players, and markedly reduced the number of cells with medium DNA damage in rugby players compared to corresponding control nonsupplemented group. Accordingly, the results of our study suggest that four-week-long magnesium supplementation has marked effects in protecting the DNA from oxidative damage in both rugby players and in young men with sedentary lifestyle. Clinical trial is registered at ANZCTR Trial Id: ACTRN12615001237572. PMID:27042258

Effect of oxidative stress from nanoscale TiO2 particles on a Physarum polycephalum macroplasmodium under dark conditions.

PubMed

Zhang, Zhi; Zhang, Jianhua; Shi, Caixia; Guo, Heng; Ni, RuiYang; Qu, Junle; Tang, Jiaoning; Liu, Shide

2017-07-01

Information regarding the effect of nanoscale titanium dioxide particles (nTiO 2 ) on the environment under dark conditions is scarce, and the effect of nTiO 2 on fungi is largely unknown. Due to its huge size and high sensitivity to external stimuli, the slime mold fungi cell, Physarum polycephalum macroplasmodium, was utilized as a novel subject for the toxicity investigations in the present study, and oxidative stress from nTiO 2 on the macroplasmodium was assessed under dark conditions. Short exposure (2-3 h) caused an intracellular reactive oxygen species (ROS) imbalance, and an anti-oxidative mechanism was activated from intermediate doses of nTiO 2 (5-18 mg/mL). At long exposure times (~3 days), relatively low doses of nTiO 2 (≤9 mg/mL) stimulated the growth of macroplasmodium and oxidative stress without DNA damage, whereas higher doses of nTiO 2 (≥15 mg/mL) led to growth inhibition, significant DNA oxidative damage, and activation of the DNA single-strand repairing system. Although DNA oxidative damage was decreased to the same level as the control group by the supplementation of the anti-oxidant vitamin C, growth of the macroplasmodium failed to be completely restored. We inferred that nTiO 2 induced a complicated toxicity effect on P. polycephalum in addition to DNA oxidative damage. Taken as a whole, the present study implied the probability of using P. polycephalum macroplasmodium for toxicity studies at the single-cell level, indicating that nTiO 2 could induce oxidative stress or damage in P. polycephalum even under dark conditions and suggesting that the release of nTiO 2 could lead to a growth imbalance of slime molds in the environment.

DNA Damage Repair Factors have a Tumor Promoting Role in MLL-fusion Leukemia | Center for Cancer Research

Cancer.gov

Cancers develop when cells accumulate DNA mutations that allow them to grow and divide inappropriately. Thus, proteins involved in repairing DNA damage are generally suppressors of cancer formation, and their expression is often lost in the early stages of cancer initiation. In contrast, cancer stem cells, like their normal counterparts, must retain their ability to self-renew, which necessitates maintenance of DNA integrity. In hematopoietic stem cells (HSC), for example, double strand breaks and oxidative damage exhaust their regenerative ability. André Nussenzweig, Ph.D., Chief of CCR’s Laboratory of Genome Integrity and his colleagues wondered whether leukemic stem cells might be similarly constrained by DNA damage.

In vivo genotoxicity of furan in F344 rats at cancer bioassay doses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Wei, E-mail: Wei.Ding@fda.hhs.gov; Petibone, Dayton M.; Latendresse, John R.

2012-06-01

Furan, a potent rodent liver carcinogen, is found in many cooked food items and thus represents a human cancer risk. Mechanisms for furan carcinogenicity were investigated in male F344 rats using the in vivo Comet and micronucleus assays, combined with analysis of histopathological and gene expression changes. In addition, formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII)-sensitive DNA damage was monitored as a measure of oxidative DNA damage. Rats were treated by gavage on four consecutive days with 2, 4, and 8 mg/kg bw furan, doses that were tumorigenic in 2-year cancer bioassays, and with two higher doses, 12 andmore » 16 mg/kg. Rats were killed 3 h after the last dose, a time established as producing maximum levels of DNA damage in livers of furan-treated rats. Liver Comet assays indicated that both DNA strand breaks and oxidized purines and pyrimidines increased in a near-linear dose-responsive fashion, with statistically significant increases detected at cancer bioassay doses. No DNA damage was detected in bone marrow, a non-target tissue for cancer, and peripheral blood micronucleus assays were negative. Histopathological evaluation of liver from furan-exposed animals produced evidence of inflammation, single-cell necrosis, apoptosis, and cell proliferation. In addition, genes related to apoptosis, cell-cycle checkpoints, and DNA-repair were expressed at a slightly lower level in the furan-treated livers. Although a mixed mode of action involving direct DNA binding cannot be ruled out, the data suggest that furan induces cancer in rat livers mainly through a secondary genotoxic mechanism involving oxidative stress, accompanied by inflammation, cell proliferation, and toxicity. -- Highlights: ► Furan is a potent rodent liver carcinogen and represents a human cancer risk. ► Furan induces DNA damage in rat liver at cancer bioassay doses. ► Furan induces oxidative stress, inflammation and cell proliferation in rat liver. ► Expression of DNA damage repair-related genes is reduced in furan-treated rat livers. ► Furan induces rat liver cancer mainly through a secondary genotoxic mechanism.« less

Hydroxychavicol, a key ingredient of Piper betle induces bacterial cell death by DNA damage and inhibition of cell division.

PubMed

Singh, Deepti; Narayanamoorthy, Shwetha; Gamre, Sunita; Majumdar, Ananda Guha; Goswami, Manish; Gami, Umesh; Cherian, Susan; Subramanian, Mahesh

2018-05-20

Antibiotic resistance is a global problem and there is an urgent need to augment the arsenal against pathogenic bacteria. The emergence of different drug resistant bacteria is threatening human lives to be pushed towards the pre-antibiotic era. Botanical sources remain a vital source of diverse organic molecules that possess antibacterial property as well as augment existing antibacterial molecules. Piper betle, a climber, is widely used in south and south-east Asia whose leaves and nuts are consumed regularly. Hydroxychavicol (HC) isolated from Piper betle has been reported to possess antibacterial activity. It is currently not clear how the antibacterial activity of HC is manifested. In this investigation we show HC generates superoxide in E. coli cells. Antioxidants protected E. coli against HC induced cell death while gshA mutant was more sensitive to HC than wild type. DNA damage repair deficient mutants are hypersensitive to HC and HC induces the expression of DNA damage repair genes that repair oxidative DNA damage. HC treated E. coli cells are inhibited from growth and undergo DNA condensation. In vitro HC binds to DNA and cleaves it in presence of copper. Our data strongly indicates HC mediates bacterial cell death by ROS generation and DNA damage. Damage to iron sulfur proteins in the cells contribute to amplification of oxidative stress initiated by HC. Further HC is active against a number of Gram negative bacteria isolated from patients with a wide range of clinical symptoms and varied antibiotic resistance profiles. Copyright © 2018 Elsevier Inc. All rights reserved.

Emulsions Made of Oils from Seeds of GM Flax Protect V79 Cells against Oxidative Stress

PubMed Central

Skorkowska-Telichowska, Katarzyna; Hasiewicz-Derkacz, Karolina; Gębarowski, Tomasz; Kulma, Anna; Kostyn, Kamil; Gębczak, Katarzyna; Szyjka, Anna; Wojtasik, Wioleta; Gąsiorowski, Kazimierz

2016-01-01

Polyunsaturated fatty acids, sterols, and hydrophilic phenolic compounds are components of flax oil that act as antioxidants. We investigated the impact of flax oil from transgenic flax in the form of emulsions on stressed Chinese hamster pulmonary fibroblasts. We found that the emulsions protect V79 cells against the H2O2 and the effect is dose dependent. They reduced the level of intracellular reactive oxygen species and protected genomic DNA against damage. The rate of cell proliferation increased upon treatment with the emulsions at a low concentration, while at a high concentration it decreased significantly, accompanied by increased frequency of apoptotic cell death. Expression analysis of selected genes revealed the upregulatory impact of the emulsions on the histones, acetylases, and deacetylases. Expression of apoptotic, proinflammatory, and anti-inflammatory genes was also altered. It is thus suggested that flax oil emulsions might be useful as a basis for biomedical products that actively protect cells against inflammation and degeneration. The beneficial effect on fibroblast resistance to oxidative damage was superior in the emulsion made of oil from transgenic plants which was correlated with the quantity of antioxidants and squalene. The emulsions from transgenic flax are promising candidates for skin protection against oxidative damage. PMID:26779302

Activation of Poly(ADP-Ribose)Polymerase in rat hepatocytes does not contribute to their cell death by oxidative stress.

PubMed

Latour, I; Leunda-Casi, A; Denef, J F; Buc Calderon, P

2000-01-10

Oxidative stress induced by tert-butyl hydroperoxide (tBOOH) in freshly isolated rat hepatocytes caused DNA damage and loss of membrane integrity. Such DNA lesions are likely to be single strand breaks since neither caryolysis nor chromatine condensation was seen in electron micrographs from tBOOH-treated cells. In addition, pulsed field gel electrophoresis of genomic DNA from both control and tBOOH-treated hepatocytes showed similar profiles, indicating the absence of internucleosomal DNA cleavage, a classical reflection of apoptotic endonuclease activity. The activation of the repair enzyme poly(ADP-ribose)polymerase (PARP) following DNA damage by tBOOH induced a dramatic drop in both NAD(+) and ATP. The inhibition of PARP by 3-aminobenzamide enhanced DNA damage by tBOOH, restored NAD(+) and ATP levels, but did not result in better survival against cell killing by tBOOH. The lack of the protective effect of PARP inhibitor, therefore, does not implicate PARP in the mechanism of tBOOH-induced cytotoxicity. Electron micrographs also show no mitochondrial swelling in cells under oxidative stress, but such organelles were mainly located around the nucleus, a picture already observed in autoschizis, a new suggested kind of cell death which shows both apoptotic and necrotic morphological characteristics. Copyright 2000 Academic Press.

Dihydroartemisinin Exerts Its Anticancer Activity through Depleting Cellular Iron via Transferrin Receptor-1

PubMed Central

Ba, Qian; Zhou, Naiyuan; Duan, Juan; Chen, Tao; Hao, Miao; Yang, Xinying; Li, Junyang; Yin, Jun; Chu, Ruiai; Wang, Hui

2012-01-01

Artemisinin and its main active metabolite dihydroartemisinin, clinically used antimalarial agents with low host toxicity, have recently shown potent anticancer activities in a variety of human cancer models. Although iron mediated oxidative damage is involved, the mechanisms underlying these activities remain unclear. In the current study, we found that dihydroartemisinin caused cellular iron depletion in time- and concentration-dependent manners. It decreased iron uptake and disturbed iron homeostasis in cancer cells, which were independent of oxidative damage. Moreover, dihydroartemisinin reduced the level of transferrin receptor-1 associated with cell membrane. The regulation of dihydroartemisinin to transferrin receptor-1 could be reversed by nystatin, a cholesterol-sequestering agent but not the inhibitor of clathrin-dependent endocytosis. Dihydroartemisinin also induced transferrin receptor-1 palmitoylation and colocalization with caveolin-1, suggesting a lipid rafts mediated internalization pathway was involved in the process. Also, nystatin reversed the influences of dihydroartemisinin on cell cycle and apoptosis related genes and the siRNA induced downregulation of transferrin receptor-1 decreased the sensitivity to dihydroartemisinin efficiently in the cells. These results indicate that dihydroartemisinin can counteract cancer through regulating cell-surface transferrin receptor-1 in a non-classical endocytic pathway, which may be a new action mechanism of DHA independently of oxidative damage. PMID:22900042

Amphetamines promote mitochondrial dysfunction and DNA damage in pulmonary hypertension

PubMed Central

Chen, Pin-I; Cao, Aiqin; Miyagawa, Kazuya; Tojais, Nancy F.; Hennigs, Jan K.; Li, Caiyun G.; Sweeney, Nathaly M.; Inglis, Audrey S.; Wang, Lingli; Li, Dan; Ye, Matthew; Feldman, Brian J.

2017-01-01

Amphetamine (AMPH) or methamphetamine (METH) abuse can cause oxidative damage and is a risk factor for diseases including pulmonary arterial hypertension (PAH). Pulmonary artery endothelial cells (PAECs) from AMPH-associated-PAH patients show DNA damage as judged by γH2AX foci and DNA comet tails. We therefore hypothesized that AMPH induces DNA damage and vascular pathology by interfering with normal adaptation to an environmental perturbation causing oxidative stress. Consistent with this, we found that AMPH alone does not cause DNA damage in normoxic PAECs, but greatly amplifies DNA damage in hypoxic PAECs. The mechanism involves AMPH activation of protein phosphatase 2A, which potentiates inhibition of Akt. This increases sirtuin 1, causing deacetylation and degradation of HIF1α, thereby impairing its transcriptional activity, resulting in a reduction in pyruvate dehydrogenase kinase 1 and impaired cytochrome c oxidase 4 isoform switch. Mitochondrial oxidative phosphorylation is inappropriately enhanced and, as a result of impaired electron transport and mitochondrial ROS increase, caspase-3 is activated and DNA damage is induced. In mice given binge doses of METH followed by hypoxia, HIF1α is suppressed and pulmonary artery DNA damage foci are associated with worse pulmonary vascular remodeling. Thus, chronic AMPH/METH can induce DNA damage associated with vascular disease by subverting the adaptive responses to oxidative stress. PMID:28138562

Modulation of proteostasis counteracts oxidative stress and affects DNA base excision repair capacity in ATM-deficient cells.

PubMed

Poletto, Mattia; Yang, Di; Fletcher, Sally C; Vendrell, Iolanda; Fischer, Roman; Legrand, Arnaud J; Dianov, Grigory L

2017-09-29

Ataxia telangiectasia (A-T) is a syndrome associated with loss of ATM protein function. Neurodegeneration and cancer predisposition, both hallmarks of A-T, are likely to emerge as a consequence of the persistent oxidative stress and DNA damage observed in this disease. Surprisingly however, despite these severe features, a lack of functional ATM is still compatible with early life, suggesting that adaptation mechanisms contributing to cell survival must be in place. Here we address this gap in our knowledge by analysing the process of human fibroblast adaptation to the lack of ATM. We identify profound rearrangement in cellular proteostasis occurring very early on after loss of ATM in order to counter protein damage originating from oxidative stress. Change in proteostasis, however, is not without repercussions. Modulating protein turnover in ATM-depleted cells also has an adverse effect on the DNA base excision repair pathway, the major DNA repair system that deals with oxidative DNA damage. As a consequence, the burden of unrepaired endogenous DNA lesions intensifies, progressively leading to genomic instability. Our study provides a glimpse at the cellular consequences of loss of ATM and highlights a previously overlooked role for proteostasis in maintaining cell survival in the absence of ATM function. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Mitochondrial transfer of mesenchymal stem cells effectively protects corneal epithelial cells from mitochondrial damage.

PubMed

Jiang, Dan; Gao, Fei; Zhang, Yuelin; Wong, David Sai Hung; Li, Qing; Tse, Hung-Fat; Xu, Goufeng; Yu, Zhendong; Lian, Qizhou

2016-11-10

Recent studies have demonstrated that mesenchymal stem cells (MSCs) can donate mitochondria to airway epithelial cells and rescue mitochondrial damage in lung injury. We sought to determine whether MSCs could donate mitochondria and protect against oxidative stress-induced mitochondrial dysfunction in the cornea. Co-culturing of MSCs and corneal epithelial cells (CECs) indicated that the efficiency of mitochondrial transfer from MSCs to CECs was enhanced by Rotenone (Rot)-induced oxidative stress. The efficient mitochondrial transfer was associated with increased formation of tunneling nanotubes (TNTs) between MSCs and CECs, tubular connections that allowed direct intercellular communication. Separation of MSCs and CECs by a transwell culture system revealed no mitochiondrial transfer from MSCs to CECs and mitochondrial function was impaired when CECs were exposed to Rot challenge. CECs with or without mitochondrial transfer from MSCs displayed a distinct survival capacity and mitochondrial oxygen consumption rate. Mechanistically, increased filopodia outgrowth in CECs for TNT formation was associated with oxidative inflammation-activated NFκB/TNFαip2 signaling pathways that could be attenuated by reactive oxygen species scavenger N-acetylcysteine (NAC) treatment. Furthermore, MSCs grown on a decellularized porcine corneal scaffold were transplanted onto an alkali-injured eye in a rabbit model. Enhanced corneal wound healing was evident following healthy MSC scaffold transplantation. And transferred mitochondria was detected in corneal epithelium. In conclusion, mitochondrial transfer from MSCs provides novel protection for the cornea against oxidative stress-induced mitochondrial damage. This therapeutic strategy may prove relevant for a broad range of mitochondrial diseases.

Male Rat Germ Cells Display Age-Dependent and Cell-Specific Susceptibility in Response to Oxidative Stress Challenges1

PubMed Central

Selvaratnam, Johanna; Paul, Catriona; Robaire, Bernard

2015-01-01

For decades male germ cells were considered unaffected by aging, due to the fact that males continue to generate sperm into old age; however, evidence indicates that germ cells from aged males are of lower quality than those of young males. The current study examines the effects of aging on pachytene spermatocytes and round spermatids, and is the first study to culture these cells in isolation for an extended period. Our objective is to determine the cell-specific responses germ cells have to aging and oxidative insult. Culturing isolated germ cells from young and aged Brown Norway rats revealed that germ cells from aged males displayed an earlier decline in viability, elevated levels of reactive oxygen species (ROS), and increased spermatocyte DNA damage, compared to young males. Furthermore, oxidative insult by prooxidant 3-morpholinosydnonimine provides insight into how spermatocytes and spermatids manage excess ROS. Genome-wide microarray analyses revealed that several transcripts for antioxidants, Sod1, Cat, and Prdxs, were up-regulated in response to ROS in germ cells from young males while being expressed at lower levels in the aged. In contrast, the expression of DNA damage repair genes Rad50 and Atm were increased in the germ cells from aged animals. Our data indicate that as germ cells undergo spermatogenesis, they adapt and respond to oxidative stress differently, depending on their phase of development, and the process of aging results in redox dysfunction. Thus, even at early stages of spermatogenesis, germ cells from aged males are unable to mount an appropriate response to manage oxidative stress. PMID:26224006

An anthocyanin-rich strawberry extract protects against oxidative stress damage and improves mitochondrial functionality in human dermal fibroblasts exposed to an oxidizing agent.

PubMed

Giampieri, Francesca; Alvarez-Suarez, José M; Mazzoni, Luca; Forbes-Hernandez, Tamara Y; Gasparrini, Massimiliano; Gonzàlez-Paramàs, Ana M; Santos-Buelga, Celestino; Quiles, Josè L; Bompadre, Stefano; Mezzetti, Bruno; Battino, Maurizio

2014-08-01

This study investigates the protective effect of the Sveva strawberry polyphenol-rich extract on human dermal fibroblasts against AAPH-induced oxidative stress. The HPLC-DAD/ESI-MS analysis was used for evaluating the phenolic composition of the fruits. Sveva strawberry presented a high anthocyanin content (639.79 mg per kg fresh fruit), representing ∼86.08% of the total phenolic content, with Pg-3-glc as the most abundant representative (611.18 mg per kg fresh fruit). Only one ellagitannin (agrimoniin) was identified, while two quercetins, three kaempherol derivates, and three ellagic acid derivatives were detected and quantified. Strawberry pre-treatment (0.5 mg ml(-1)) markedly increased human dermal fibroblast viability, with a significant reduction of apoptotic and dead cells, and suppressed AAPH-induced ROS generation, after only 30 minutes of incubation with the oxidizing agent, and lipid peroxidation, against a range of AAPH concentrations tested. Notably, the strawberry extract also improved the mitochondrial functionality: the basal respiratory performance after treatment was ∼1.59-fold higher compared to control cells, while pre-treatment with strawberry extract before oxidative damage increased ∼2.70-fold compared to stressed cells. Our results confirm that the strawberry possesses antioxidant properties, and may be useful for the prevention of free radical-induced skin damage.

Thermosensitive hydrogel made of ferulic acid-gelatin and chitosan glycerophosphate.

PubMed

Cheng, Yung-Hsin; Yang, Shu-Hua; Liu, Chia-Ching; Gefen, Amit; Lin, Feng-Huei

2013-02-15

Reactive oxygen species-induced oxidative stress is involved in apoptosis of nucleus pulposus (NP) cells that can alter cellular phenotype and accelerate disc degeneration. Ferulic acid (FA) possesses an excellent antioxidant and anti-inflammatory properties. In the study, we developed the thermosensitive FA-gelatin/chitosan/glycerol phosphate (FA-G/C/GP) hydrogel which was applied as a sustained release system of FA to treat NP cells from the damage caused by oxidative stress. The gelation temperature of the FA-G/C/GP hydrogel was 32.17 °C. NP cells submitted to oxidative stress promoted by H(2)O(2), and post-treated with FA-G/C/GP exhibited down-regulation of MMP-3 and up-regulation aggrecan and type II collagen in mRNA level. The sulfated-glycosaminoglycan production was increased and the apoptosis was inhibited in the post-treatment group. The results suggest that the thermosensitive FA-G/C/GP hydrogel can treat NP cells from the damage caused by oxidative stress and may apply in minimally invasive surgery for NP regeneration. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inhibition property of green tea extract in relation to reserpine-induced ribosomal strips of rough endoplasmic reticulum (rER) of the rat kidney proximal tubule cells.

PubMed

Abdel-Majeed, Safer; Mohammad, Afzal; Shaima, Al-Bloushi; Mohammad, Rafique; Mousa, Shaker A

2009-12-01

The aim of this study was to evaluate the effect of green tea in inhibiting and reversing the nephrotoxicity of reserpine--a potent oxidative stress inducer--which induced cellular kidney damage. Serum biochemical parameters, antioxidant enzyme levels, thiobarbituric acid reactive substances (TBARS) and serum transaminases (glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT)) values and histopathology were systematically evaluated. Reserpine exposure led to increase the oxidative stress and organ injury was significantly observed through biochemical parameters and ultrastructural evaluation. Sprague-Dawely (S.D.) rats were intraperitonealy administered reserpine to induce oxidative kidney damage. Experimental rats were given green tea extract according to the protocol given below. Sixty rats were randomly divided into six groups, with 10 rats in each group. Reserpine was found to cause kidney proximal tubule damage, such as stripping and clustering of ribosomes from the rough endoplasmic reticulum (rER) and demolishing of mitochondrial christae with elevated level of oxidative stress markers, such as TBARS. While the ultrastructural study showed a revival of kidney proximal tubule cells as a result of the administration of green tea extract to rats. We suggest that green tea might elevate antioxidant defense system, clean up free radicals, lessen oxidative damages and protect kidney against reserpine-induced toxicity and thus had a potential protective effect.

Live-cell Imaging Approaches for the Investigation of Xenobiotic-Induced Oxidant Stress

EPA Science Inventory

BACKGROUND: Oxidant stress is arguably a universal feature in toxicology. Research studies on the role of oxidant stress induced by xenobiotic exposures have typically relied on the identification of damaged biomolecules using a variety of conventional biochemical and molecular t...

The Role of Oxidative Stress in Apoptosis of Breast Cancer.

DTIC Science & Technology

1995-09-27

supported by studies demonstrating that inappropriate expression of an oncogene, bcl - 2 , prevents cell death and thereby promotes Page _1L ANNUAL REPORT...see Appendix: Baker et al., "Decreased Antioxidant Defense and Increased Oxidant Stress During Dexamethasone-Induced Apoptosis: bcl - 2 Selectively...Alzheimer’s disease. The bcl - 2 oncogene blocks apoptosis in diverse systems and protects cells against oxidative stress- induced damage (Hockenbery et

Insulin is a potential antioxidant for diabetes-associated cognitive decline via regulating Nrf2 dependent antioxidant enzymes.

PubMed

Song, Ying; Ding, Wei; Bei, Yun; Xiao, Yan; Tong, Hai-Da; Wang, Li-Bo; Ai, Li-Yao

2018-05-21

To investigate the neuroprotective effects of insulin on diabetic encephalopathy and its mechanism. The diabetic model was established by injection of streptozotocin. Behavior examinations were conducted by the Morris water maze. Histopathological alterations were detected by HE staining. ROS, CAT levels and SOD activity were measured using a microplate reader. In vitro, the viability of wild type and knock-down PC12 cells was detected by MTT assay, the morphology of cells was monitored under a microscope. The subcellular distribution of Nrf2 was observed by western blotting and immunohistochemistry. Evident oxidative stress injury was observed in diabetic rats and H 2 O 2 -induced PC12 cells. Insulin not only protect diabetic rat from oxidative stress injury but also significantly inhibited H 2 O 2 -induced apoptosis and intracellular ROS in cells. In addition, the level of malondialdehyde was reduced, and the activities of superoxide dismutase, catalase and glutathione peroxidase were augmented in both diabetic rats and PC12 cells. Interestingly, insulin promoted the translocation of Nrf2 into the nucleus and activation of downstream antioxidant protein expression. Further, the Nrf2 knockdown cells suffered more serious H 2 O 2 -induced damage than the wild PC12 cells. Moreover, insulin had no significant protective effect on knockdown cells with H 2 O 2 -damage. Collectively, our results suggested that insulin significantly inhibited neuronal damage through the Nrf2 signaling pathway, which regulates endogenous oxidant-antioxidant balance, therefore, insulin may be a potential protective agent for the treatment of oxidative stress-induced diabetic encephalopathy. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Thermotolerance, oxidative stress, apoptosis, heat-shock proteins and damages to reproductive cells of insecticide-susceptible and -resistant strains of the diamondback moth Plutella xylostella.

PubMed

Zhang, L J; Chen, J L; Yang, B L; Kong, X G; Bourguet, D; Wu, G

2017-08-01

In this study, we investigated thermotolerance, several physiological responses and damage to reproductive cells in chlorpyrifos-resistant (Rc) and -susceptible (Sm) strains of the diamondback moth, Plutella xylostella subjected to heat stress. The chlorpyrifos resistance of these strains was mediated by a modified acetylcholinesterase encoded by an allele, ace1R, of the ace1 gene. Adults of the Rc strain were less heat resistant than those of the Sm strain; they also had lower levels of enzymatic activity against oxidative damage, higher reactive oxygen species contents, weaker upregulation of two heat shock protein (hsp) genes (hsp69s and hsp20), and stronger upregulation of two apoptotic genes (caspase-7 and -9). The damage to sperm and ovary cells was greater in Rc adults than in Sm adults and was temperature sensitive. The lower fitness of the resistant strain, compared with the susceptible strain, is probably due to higher levels of oxidative stress and apoptosis, which also have deleterious effects on several life history traits. The greater injury observed in conditions of heat stress may be due to both the stronger upregulation of caspase genes and weaker upregulation of hsp genes in resistant than in susceptible individuals.

Genetic disruption of SOD1 gene causes glucose intolerance and impairs β-cell function.

PubMed

Muscogiuri, Giovanna; Salmon, Adam B; Aguayo-Mazzucato, Cristina; Li, Mengyao; Balas, Bogdan; Guardado-Mendoza, Rodolfo; Giaccari, Andrea; Reddick, Robert L; Reyna, Sara M; Weir, Gordon; Defronzo, Ralph A; Van Remmen, Holly; Musi, Nicolas

2013-12-01

Oxidative stress has been associated with insulin resistance and type 2 diabetes. However, it is not clear whether oxidative damage is a cause or a consequence of the metabolic abnormalities present in diabetic subjects. The goal of this study was to determine whether inducing oxidative damage through genetic ablation of superoxide dismutase 1 (SOD1) leads to abnormalities in glucose homeostasis. We studied SOD1-null mice and wild-type (WT) littermates. Glucose tolerance was evaluated with intraperitoneal glucose tolerance tests. Peripheral and hepatic insulin sensitivity was quantitated with the euglycemic-hyperinsulinemic clamp. β-Cell function was determined with the hyperglycemic clamp and morphometric analysis of pancreatic islets. Genetic ablation of SOD1 caused glucose intolerance, which was associated with reduced in vivo β-cell insulin secretion and decreased β-cell volume. Peripheral and hepatic insulin sensitivity were not significantly altered in SOD1-null mice. High-fat diet caused glucose intolerance in WT mice but did not further worsen the glucose intolerance observed in standard chow-fed SOD1-null mice. Our findings suggest that oxidative stress per se does not play a major role in the pathogenesis of insulin resistance and demonstrate that oxidative stress caused by SOD1 ablation leads to glucose intolerance secondary to β-cell dysfunction.

Genetic Disruption of SOD1 Gene Causes Glucose Intolerance and Impairs β-Cell Function

PubMed Central

Muscogiuri, Giovanna; Salmon, Adam B.; Aguayo-Mazzucato, Cristina; Li, Mengyao; Balas, Bogdan; Guardado-Mendoza, Rodolfo; Giaccari, Andrea; Reddick, Robert L.; Reyna, Sara M.; Weir, Gordon; DeFronzo, Ralph A.; Van Remmen, Holly; Musi, Nicolas

2013-01-01

Oxidative stress has been associated with insulin resistance and type 2 diabetes. However, it is not clear whether oxidative damage is a cause or a consequence of the metabolic abnormalities present in diabetic subjects. The goal of this study was to determine whether inducing oxidative damage through genetic ablation of superoxide dismutase 1 (SOD1) leads to abnormalities in glucose homeostasis. We studied SOD1-null mice and wild-type (WT) littermates. Glucose tolerance was evaluated with intraperitoneal glucose tolerance tests. Peripheral and hepatic insulin sensitivity was quantitated with the euglycemic-hyperinsulinemic clamp. β-Cell function was determined with the hyperglycemic clamp and morphometric analysis of pancreatic islets. Genetic ablation of SOD1 caused glucose intolerance, which was associated with reduced in vivo β-cell insulin secretion and decreased β-cell volume. Peripheral and hepatic insulin sensitivity were not significantly altered in SOD1-null mice. High-fat diet caused glucose intolerance in WT mice but did not further worsen the glucose intolerance observed in standard chow–fed SOD1-null mice. Our findings suggest that oxidative stress per se does not play a major role in the pathogenesis of insulin resistance and demonstrate that oxidative stress caused by SOD1 ablation leads to glucose intolerance secondary to β-cell dysfunction. PMID:24009256

Oxidative Stress, Bone Marrow Failure, and Genome Instability in Hematopoietic Stem Cells

PubMed Central

Richardson, Christine; Yan, Shan; Vestal, C. Greer

2015-01-01

Reactive oxygen species (ROS) can be generated by defective endogenous reduction of oxygen by cellular enzymes or in the mitochondrial respiratory pathway, as well as by exogenous exposure to UV or environmental damaging agents. Regulation of intracellular ROS levels is critical since increases above normal concentrations lead to oxidative stress and DNA damage. A growing body of evidence indicates that the inability to regulate high levels of ROS leading to alteration of cellular homeostasis or defective repair of ROS-induced damage lies at the root of diseases characterized by both neurodegeneration and bone marrow failure as well as cancer. That these diseases may be reflective of the dynamic ability of cells to respond to ROS through developmental stages and aging lies in the similarities between phenotypes at the cellular level. This review summarizes work linking the ability to regulate intracellular ROS to the hematopoietic stem cell phenotype, aging, and disease. PMID:25622253

Role of Unfolded Protein Response Dysregulation in Oxidative Injury of Retinal Pigment Epithelial Cells

PubMed Central

Chen, Chen; Cano, Marisol; Wang, Joshua J.; Li, Jingming; Huang, Chuangxin; Yu, Qiang; Herbert, Terence P.; Handa, James T.

2014-01-01

Abstract Aims: Age-related macular degeneration (AMD), a major cause of legal blindness in the elderly, is associated with genetic and environmental risk factors, such as cigarette smoking. Recent evidence shows that cigarette smoke (CS) that contains high levels of potent oxidants preferably targets retinal pigment epithelium (RPE) leading to oxidative damage and apoptosis; however, the mechanisms are poorly understood. The present study aimed to investigate the role of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in CS-related RPE apoptosis. Results: ER stress and proapoptotic gene C/EBP homologous protein (CHOP) were induced in the RPE/choroid complex from mice exposed to CS for 2 weeks and in human RPE cells treated with hydroquinone, a potent oxidant found at high concentrations in CS. Suppressing ER stress or inhibiting CHOP activation by pharmacological chaperones or genetic approaches attenuated hydroquinone-induced RPE cell apoptosis. In contrast to enhanced CHOP activation, protein level of active X-box binding protein 1 (XBP1), a major regulator of the adaptive UPR, was reduced in hydroquinone-treated cells. Conditional knockout of XBP1 gene in the RPE resulted in caspase-12 activation, increased CHOP expression, and decreased antiapoptotic gene Bcl-2. Furthermore, XBP1-deficient RPE cells are more sensitive to oxidative damage induced by hydroquinone or NaIO3, a CS-unrelated chemical oxidant. Conversely, overexpressing XBP1 protected RPE cells and attenuated oxidative stress-induced RPE apoptosis. Innovation and Conclusion: These findings provide strong evidence suggesting an important role of ER stress and the UPR in CS-related oxidative injury of RPE cells. Thus, the modulation of the UPR signaling may provide a promising target for the treatment of AMD. Antioxid. Redox Signal. 20, 2091–2106. PMID:24053669

Plant Flavone Apigenin Binds to Nucleic Acid Bases and Reduces Oxidative DNA Damage in Prostate Epithelial Cells

PubMed Central

Bhaskaran, Natarajan; Gupta, Sanjay

2014-01-01

Oxidative stress has been linked to prostate carcinogenesis as human prostate tissue is vulnerable to oxidative DNA damage. Apigenin, a dietary plant flavone, possesses anti-proliferative and anticancer effects; however, its antioxidant properties have not been fully elucidated. We investigated sub-cellular distribution of apigenin, it’s binding to DNA and protective effects against H2O2-induced DNA damage using transformed human prostate epithelial RWPE-1 cells and prostate cancer LNCaP, PC-3 and DU145 cells. Exposure of cells to apigenin exhibited higher accumulation in RWPE-1 and LNCaP cells, compared to PC-3 and DU145 cells. The kinetics of apigenin uptake in LNCaP cells was estimated with a Km value of 5 µmole/L and Vmax of 190 pmoles/million cells/h. Sub-cellular fractionation demonstrated that nuclear matrix retains the highest concentration of apigenin (45.3%), followed by cytosol (23.9%), nuclear membranes (17.9%) and microsomes (12.9%), respectively. Spectroscopic analysis of apigenin with calf-thymus DNA exhibited intercalation as the dominant binding mode to DNA duplex. Apigenin exposure resulted in significant genoprotective effects in H2O2-stressed RWPE-1 cells by reduction in reactive oxygen species levels. In addition, apigenin exposure suppressed the formation of 8-hydroxy-2′ deoxyguanosine and protected exposed cells from apoptosis. Our studies demonstrate that apigenin is readily taken up by normal prostatic epithelial cells and prostate cancer cells, and is incorporated into their nuclei, where its intercalation with nucleic acid bases may account for its antioxidant and chemopreventive activities. PMID:24614817

Plant flavone apigenin binds to nucleic acid bases and reduces oxidative DNA damage in prostate epithelial cells.

PubMed

Sharma, Haripaul; Kanwal, Rajnee; Bhaskaran, Natarajan; Gupta, Sanjay

2014-01-01

Oxidative stress has been linked to prostate carcinogenesis as human prostate tissue is vulnerable to oxidative DNA damage. Apigenin, a dietary plant flavone, possesses anti-proliferative and anticancer effects; however, its antioxidant properties have not been fully elucidated. We investigated sub-cellular distribution of apigenin, it's binding to DNA and protective effects against H2O2-induced DNA damage using transformed human prostate epithelial RWPE-1 cells and prostate cancer LNCaP, PC-3 and DU145 cells. Exposure of cells to apigenin exhibited higher accumulation in RWPE-1 and LNCaP cells, compared to PC-3 and DU145 cells. The kinetics of apigenin uptake in LNCaP cells was estimated with a Km value of 5 µmole/L and Vmax of 190 pmoles/million cells/h. Sub-cellular fractionation demonstrated that nuclear matrix retains the highest concentration of apigenin (45.3%), followed by cytosol (23.9%), nuclear membranes (17.9%) and microsomes (12.9%), respectively. Spectroscopic analysis of apigenin with calf-thymus DNA exhibited intercalation as the dominant binding mode to DNA duplex. Apigenin exposure resulted in significant genoprotective effects in H2O2-stressed RWPE-1 cells by reduction in reactive oxygen species levels. In addition, apigenin exposure suppressed the formation of 8-hydroxy-2' deoxyguanosine and protected exposed cells from apoptosis. Our studies demonstrate that apigenin is readily taken up by normal prostatic epithelial cells and prostate cancer cells, and is incorporated into their nuclei, where its intercalation with nucleic acid bases may account for its antioxidant and chemopreventive activities.

Effects of dietary almond- and olive oil-based docosahexaenoic acid- and vitamin E-enriched beverage supplementation on athletic performance and oxidative stress markers.

PubMed

Capó, X; Martorell, M; Busquets-Cortés, C; Sureda, A; Riera, J; Drobnic, F; Tur, J A; Pons, A

2016-12-07

Functional beverages based on almonds and olive oil and enriched with α-tocopherol and docosahexaenoic acid (DHA) could be useful in modulating oxidative stress and enhancing physical performance in sportsmen. The aim of this work was to evaluate the effects of supplementation with functional beverages on physical performance, plasma and erythrocyte fatty acids' and polyphenol handling, oxidative and nitrative damage, and antioxidant and mitochondrial gene expression in young and senior athletes. Athletes performed maximal exercise tests before and after one month of dietary supplementation and blood samples were taken immediately before and one hour after each test. The beverages did not alter performance parameters during maximal exercise. Supplementation increased polyunsaturated and reduced saturated plasma fatty acids while increasing the DHA erythrocyte content; it maintained basal plasma and blood polyphenol levels, but increased the blood cell polyphenol concentration in senior athletes. Supplementation protects against oxidative damage although it enhances nitrative damage in young athletes. The beverages enhance the gene expression of antioxidant enzymes in peripheral blood mononuclear cells after exercise in young athletes.

Root Damage under Alkaline Stress Is Associated with Reactive Oxygen Species Accumulation in Rice (Oryza sativa L.)

PubMed Central

Zhang, Hui; Liu, Xiao-Long; Zhang, Rui-Xue; Yuan, Hai-Yan; Wang, Ming-Ming; Yang, Hao-Yu; Ma, Hong-Yuan; Liu, Duo; Jiang, Chang-Jie; Liang, Zheng-Wei

2017-01-01

Alkaline stress (high pH) severely damages root cells, and consequently, inhibits rice (Oryza sativa L.) seedling growth. In this study, we demonstrate the accumulation of reactive oxygen species (ROS) in root cells under alkaline stress. Seedlings of two rice cultivars with different alkaline tolerances, ‘Dongdao-4’ (moderately alkaline-tolerant) and ‘Jiudao-51’ (alkaline-sensitive), were subjected to alkaline stress simulated by 15 mM sodium carbonate (Na2CO3). Alkaline stress greatly reduced seedling survival rate, shoot and root growth, and root vigor. Moreover, severe root cell damage was observed under alkaline stress, as shown by increased membrane injury, malondialdehyde accumulation, and Evan’s Blue staining. The expression of the cell death-related genes OsKOD1, OsHsr203j, OsCP1, and OsNAC4 was consistently upregulated, while that of a cell death-suppressor gene, OsBI1, was downregulated. Analysis of the ROS contents revealed that alkaline stress induced a marked accumulation of superoxide anions (O2•-) and hydrogen peroxide (H2O2) in rice roots. The application of procyanidins (a potent antioxidant) to rice seedlings 24 h prior to alkaline treatment significantly alleviated alkalinity-induced root damage and promoted seedling growth inhibition, which were concomitant with reduced ROS accumulation. These results suggest that root cell damage, and consequently growth inhibition, of rice seedlings under alkaline stress is closely associated with ROS accumulation. The antioxidant activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase increased under alkaline stress in the roots, probably in response to the cellular damage induced by oxidative stress. However, this response mechanism may be overwhelmed by the excess ROS accumulation observed under stress, resulting in oxidative damage to root cells. Our findings provide physiological insights into the molecular mechanisms of alkalinity-induced damage to root cells, and will contribute to the improvement of alkaline stress tolerance in rice plants. PMID:28943882

Root Damage under Alkaline Stress Is Associated with Reactive Oxygen Species Accumulation in Rice (Oryza sativa L.).

PubMed

Zhang, Hui; Liu, Xiao-Long; Zhang, Rui-Xue; Yuan, Hai-Yan; Wang, Ming-Ming; Yang, Hao-Yu; Ma, Hong-Yuan; Liu, Duo; Jiang, Chang-Jie; Liang, Zheng-Wei

2017-01-01

Alkaline stress (high pH) severely damages root cells, and consequently, inhibits rice ( Oryza sativa L.) seedling growth. In this study, we demonstrate the accumulation of reactive oxygen species (ROS) in root cells under alkaline stress. Seedlings of two rice cultivars with different alkaline tolerances, 'Dongdao-4' (moderately alkaline-tolerant) and 'Jiudao-51' (alkaline-sensitive), were subjected to alkaline stress simulated by 15 mM sodium carbonate (Na 2 CO 3 ). Alkaline stress greatly reduced seedling survival rate, shoot and root growth, and root vigor. Moreover, severe root cell damage was observed under alkaline stress, as shown by increased membrane injury, malondialdehyde accumulation, and Evan's Blue staining. The expression of the cell death-related genes OsKOD1 , OsHsr203j , OsCP1 , and OsNAC4 was consistently upregulated, while that of a cell death-suppressor gene, OsBI1 , was downregulated. Analysis of the ROS contents revealed that alkaline stress induced a marked accumulation of superoxide anions ([Formula: see text]) and hydrogen peroxide (H 2 O 2 ) in rice roots. The application of procyanidins (a potent antioxidant) to rice seedlings 24 h prior to alkaline treatment significantly alleviated alkalinity-induced root damage and promoted seedling growth inhibition, which were concomitant with reduced ROS accumulation. These results suggest that root cell damage, and consequently growth inhibition, of rice seedlings under alkaline stress is closely associated with ROS accumulation. The antioxidant activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase increased under alkaline stress in the roots, probably in response to the cellular damage induced by oxidative stress. However, this response mechanism may be overwhelmed by the excess ROS accumulation observed under stress, resulting in oxidative damage to root cells. Our findings provide physiological insights into the molecular mechanisms of alkalinity-induced damage to root cells, and will contribute to the improvement of alkaline stress tolerance in rice plants.

DNA damage and apoptosis induction by the pesticide Mancozeb in rat cells: Involvement of the oxidative mechanism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calviello, Gabriella; Piccioni, Elisabetta; Boninsegna, Alma

The DNA damaging and proapoptotic effects of Mancozeb, a widely used fungicide of the ethylene-bis-dithiocarbamate (EBDC) group, were studied in RAT-1 fibroblasts cultured in vitro and in peripheral blood mononucleated cells (PBMC) isolated from Wistar rats. After 1 h exposition to Mancozeb (up to 500 ng/ml), cells produced a dose-dependent induction in DNA single strand break (SSB) formation, measured by single cell gel electrophoresis (SCGE). Concomitantly, a concentration-dependent increase in the levels of the oxidative markers of DNA oxidation, the DNA adduct 8-hydroxy-2'-deoxyguanosine (8-OHdG) and of reactive oxygen species (ROS) were observed, suggesting a prooxidant action of Mancozeb. PBMC weremore » less responsive than fibroblasts to the oxidative insult carried out by Mancozeb, as shown by the lower increase in the levels of ROS, 8-OHdG adducts and SSB measured in these cells after exposure to the pesticide. A 4-h treatment with Mancozeb induced also apoptosis in both PBMC and RAT-1 cells, even though leukocytes were less sensitive than fibroblasts to the proapoptotic action. This effect was dose-dependent and was inhibited by the action of the antioxidant {alpha}-tocopherol. The proapoptotic effect was accompanied by the altered expression of several proteins involved in the regulation of apoptosis, such as the prosurvival protein BCL-2 and the proapoptotic protein c-MYC. Exposition of cells to higher concentrations of Mancozeb or for longer periods (>4 h) caused post-apoptotic, necrotic alterations in cell membrane integrity. The data herein presented demonstrate the oxidative effect of Mancozeb and suggest that its prooxidant action may be involved in the proapoptotic effect exerted by this compound in rat cells. It appears possible that the observed oxidative and genotoxic damage may be involved in the pathogenesis of various pathologies associated with the chronic exposition to Mancozeb, including cancer. On the other hand, the proapoptotic effect of Mancozeb suggests its possible relevance in the pathogenesis of neurodegenerative diseases, often related to the exposition of pesticides.« less

Ultrastructural Interactions and Genotoxicity Assay of Cerium Dioxide Nanoparticles on Mouse Oocytes

PubMed Central

Courbiere, Blandine; Auffan, Mélanie; Rollais, Raphaël; Tassistro, Virginie; Bonnefoy, Aurélie; Botta, Alain; Rose, Jérôme; Orsière, Thierry; Perrin, Jeanne

2013-01-01

Cerium dioxide nanoparticles (CeO2 ENPs) are on the priority list of nanomaterials requiring evaluation. We performed in vitro assays on mature mouse oocytes incubated with CeO2 ENPs to study (1) physicochemical biotransformation of ENPs in culture medium; (2) ultrastructural interactions with follicular cells and oocytes using Transmission Electron Microscopy (TEM); (3) genotoxicity of CeO2 ENPs on follicular cells and oocytes using a comet assay. DNA damage was quantified as Olive Tail Moment. We show that ENPs aggregated, but their crystal structure remained stable in culture medium. TEM showed endocytosis of CeO2 ENP aggregates in follicular cells. In oocytes, CeO2 ENP aggregates were only observed around the zona pellucida (ZP). The comet assay revealed significant DNA damage in follicular cells. In oocytes, the comet assay showed a dose-related increase in DNA damage and a significant increase only at the highest concentrations. DNA damage decreased significantly both in follicular cells and in oocytes when an anti-oxidant agent was added in the culture medium. We hypothesise that at low concentrations of CeO2 ENPs oocytes could be protected against indirect oxidative stress due to a double defence system composed of follicular cells and ZP. PMID:24185910

Cellular defense against UVB-induced phototoxicity by cytosolic NADP(+)-dependent isocitrate dehydrogenase.

PubMed

Jo, Seung-Hee; Lee, So-Hyun; Chun, Hang Suk; Lee, Su Min; Koh, Ho-Jin; Lee, Sung-Eun; Chun, Jang-Soo; Park, Jeen-Woo; Huh, Tae-Lin

2002-03-29

Ultraviolet (UV) radiation is known as a major cause of skin photoaging and photocarcinogenesis. Many harmful effects of UV radiation are associated with the generation of reactive oxygen species. Recently, we have shown that NADP(+)-dependent isocitrate dehydrogenase is involved in the supply of NADPH needed for GSH production against cellular oxidative damage. In this study we investigated the role of cytosolic form of NADP(+)-dependent isocitrate dehydrogenase (IDPc) against UV radiation-induced cytotoxicity by comparing the relative degree of cellular responses in three different NIH3T3 cells with stable transfection with the cDNA for mouse IDPc in sense and antisense orientations, where IDPc activities were 2.3-fold higher and 39% lower, respectively, than that in the parental cells carrying the vector alone. Upon exposure to UVB (312 nm), the cells with low levels of IDPc became more sensitive to cell killing. Lipid peroxidation, protein oxidation, oxidative DNA damage, and intracellular peroxide generation were higher in the cell-line expressing the lower level of IDPc. However, the cells with the highly overexpressed IDPc exhibited enhanced resistance against UV radiation, compared to the control cells. The data indicate that IDPc plays an important role in cellular defense against UV radiation-induced oxidative injury. (c)2002 Elsevier Science (USA).

Antioxidant Protective Effect of Honey in Cigarette Smoke-Induced Testicular Damage in Rats

PubMed Central

Mohamed, Mahaneem; Sulaiman, Siti Amrah; Jaafar, Hasnan; Sirajudeen, Kuttulebbai Nainamohamed Salam

2011-01-01

Cigarette smoke (CS) can cause testicular damage and we investigated the possible protective effect of honey against CS-induced testicular damage and oxidative stress in rats. CS exposure (8 min, 3 times daily) and honey supplementation (1.2 g/kg daily) were given for 13 weeks. Rats exposed to CS significantly had smaller seminiferous tubules diameter and epithelial height, lower Leydig cell count and increased percentage of tubules with germ cell loss. CS also produced increased lipid peroxidation (TBARS) and glutathione peroxidase (GPx) activity, as well as reduced total antioxidant status (TAS) and activities of superoxide dismutase (SOD) and catalase (CAT). However, supplementation of honey significantly reduced histological changes and TBARS level, increased TAS level, as well as significantly restored activities of GPx, SOD and CAT in rat testis. These findings may suggest that honey has a protective effect against damage and oxidative stress induced by CS in rat testis. PMID:22016605

Antioxidant protective effect of honey in cigarette smoke-induced testicular damage in rats.

PubMed

Mohamed, Mahaneem; Sulaiman, Siti Amrah; Jaafar, Hasnan; Sirajudeen, Kuttulebbai Nainamohamed Salam

2011-01-01

Cigarette smoke (CS) can cause testicular damage and we investigated the possible protective effect of honey against CS-induced testicular damage and oxidative stress in rats. CS exposure (8 min, 3 times daily) and honey supplementation (1.2 g/kg daily) were given for 13 weeks. Rats exposed to CS significantly had smaller seminiferous tubules diameter and epithelial height, lower Leydig cell count and increased percentage of tubules with germ cell loss. CS also produced increased lipid peroxidation (TBARS) and glutathione peroxidase (GPx) activity, as well as reduced total antioxidant status (TAS) and activities of superoxide dismutase (SOD) and catalase (CAT). However, supplementation of honey significantly reduced histological changes and TBARS level, increased TAS level, as well as significantly restored activities of GPx, SOD and CAT in rat testis. These findings may suggest that honey has a protective effect against damage and oxidative stress induced by CS in rat testis.

House dust mite-induced asthma causes oxidative damage and DNA double-strand breaks in the lungs.

PubMed

Chan, Tze Khee; Loh, Xin Yi; Peh, Hong Yong; Tan, W N Felicia; Tan, W S Daniel; Li, Na; Tay, Ian J J; Wong, W S Fred; Engelward, Bevin P

2016-07-01

Asthma is related to airway inflammation and oxidative stress. High levels of reactive oxygen and nitrogen species can induce cytotoxic DNA damage. Nevertheless, little is known about the possible role of allergen-induced DNA damage and DNA repair as modulators of asthma-associated pathology. We sought to study DNA damage and DNA damage responses induced by house dust mite (HDM) in vivo and in vitro. We measured DNA double-strand breaks (DSBs), DNA repair proteins, and apoptosis in an HDM-induced allergic asthma model and in lung samples from asthmatic patients. To study DNA repair, we treated mice with the DSB repair inhibitor NU7441. To study the direct DNA-damaging effect of HDM on human bronchial epithelial cells, we exposed BEAS-2B cells to HDM and measured DNA damage and reactive oxygen species levels. HDM challenge increased lung levels of oxidative damage to proteins (3-nitrotyrosine), lipids (8-isoprostane), and nucleic acid (8-oxoguanine). Immunohistochemical evidence for HDM-induced DNA DSBs was revealed by increased levels of the DSB marker γ Histone 2AX (H2AX) foci in bronchial epithelium. BEAS-2B cells exposed to HDM showed enhanced DNA damage, as measured by using the comet assay and γH2AX staining. In lung tissue from human patients with asthma, we observed increased levels of DNA repair proteins and apoptosis, as shown by caspase-3 cleavage, caspase-activated DNase levels, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining. Notably, NU7441 augmented DNA damage and cytokine production in the bronchial epithelium and apoptosis in the allergic airway, implicating DSBs as an underlying driver of asthma pathophysiology. This work calls attention to reactive oxygen and nitrogen species and HDM-induced cytotoxicity and to a potential role for DNA repair as a modulator of asthma-associated pathophysiology. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

The apoptotic effect and the plausible mechanism of microwave radiation on rat myocardial cells.

PubMed

Zhu, Wenhe; Cui, Yan; Feng, Xianmin; Li, Yan; Zhang, Wei; Xu, Junjie; Wang, Huiyan; Lv, Shijie

2016-08-01

Microwaves may exert adverse biological effects on the cardiovascular system at the integrated system and cellular levels. However, the mechanism underlying such effects remains poorly understood. Here, we report a previously uncharacterized mechanism through which microwaves damage myocardial cells. Rats were treated with 2450 MHz microwave radiation at 50, 100, 150, or 200 mW/cm(2) for 6 min. Microwave treatment significantly enhanced the levels of various enzymes in serum. In addition, it increased the malondialdehyde content while decreasing the levels of antioxidative stress enzymes, activities of enzyme complexes I-IV, and ATP in myocardial tissues. Notably, irradiated myocardial cells exhibited structural damage and underwent apoptosis. Furthermore, Western blot analysis revealed significant changes in expression levels of proteins involved in oxidative stress regulation and apoptotic signaling pathways, indicating that microwave irradiation could induce myocardial cell apoptosis by interfering with oxidative stress and cardiac energy metabolism. Our findings provide useful insights into the mechanism of microwave-induced damage to the cardiovascular system.

Mitochondria are required for ATM activation by extranuclear oxidative stress in cultured human hepatoblastoma cell line Hep G2 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morita, Akinori, E-mail: morita@tokushima-u.ac.jp; Department of Radiological Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8509; Tanimoto, Keiji

2014-01-24

Highlights: • Oxidative ATM activation can occur in the absence of nuclear DNA damage response. • The oxidized Hep G2 cells were subjected to subcellular fractionation. • The obtained results suggest that the ATM activation occurs in mitochondria. • ATM failed to respond to oxidative stress in mitochondria-depleted Hep G2 cells. • Mitochondria are required for the oxidative activation of ATM. - Abstract: Ataxia–telangiectasia mutated (ATM) is a serine/threonine protein kinase that plays a central role in DNA damage response (DDR). A recent study reported that oxidized ATM can be active in the absence of DDR. However, the issue ofmore » where ATM is activated by oxidative stress remains unclear. Regarding the localization of ATM, two possible locations, namely, mitochondria and peroxisomes are possible. We report herein that ATM can be activated when exposed to hydrogen peroxide without inducing nuclear DDR in Hep G2 cells, and the oxidized cells could be subjected to subcellular fractionation. The first detergent-based fractionation experiment revealed that active, phosphorylated ATM was located in the second fraction, which also contained both mitochondria and peroxisomes. An alternative fractionation method involving homogenization and differential centrifugation, which permits the light membrane fraction containing peroxisomes to be produced, but not mitochondria, revealed that the light membrane fraction contained only traces of ATM. In contrast, the heavy membrane fraction, which mainly contained mitochondrial components, was enriched in ATM and active ATM, suggesting that the oxidative activation of ATM occurs in mitochondria and not in peroxisomes. In Rho 0-Hep G2 cells, which lack mitochondrial DNA and functional mitochondria, ATM failed to respond to hydrogen peroxide, indicating that mitochondria are required for the oxidative activation of ATM. These findings strongly suggest that ATM can be activated in response to oxidative stress in mitochondria and that this occurs in a DDR-independent manner.« less

Attenuation of Oxidative Stress-Induced Cell Apoptosis in Schwann RSC96 Cells by Ocimum Gratissimum Aqueous Extract

PubMed Central

Chao, Pei-Yu; Lin, James A.; Ye, Je-Chiuan; Hwang, Jin-Ming; Ting, Wei-Jen; Huang, Chih-Yang; Liu, Jer-Yuh

2017-01-01

Objectives:Cell transplantation therapy of Schwann cells (SCs) is a promising therapeutic strategy after spinal cord injury. However, challenges such as oxidative stress hinder satisfactory cell viability and intervention for enhancing SCs survival is critical throughout the transplantation procedures. Ocimum gratissimum, widely used as a folk medicine in many countries, has therapeutic and anti-oxidative properties and may protect SCs survival. Methods:We examined the protective effects of aqueous O. gratissimum extract (OGE) against cell damage caused by H2O2-induced oxidative stress in RSC96 Schwann cells. Results:Our results showed that the RSC96 cells, damaged by H2O2 oxidative stress, decreased their viability up to 32% after treatment with different concentrations of up to 300 μM H2O2, but OGE pretreatment (150 or 200 μg/mL) increased cell viability by approximately 62% or 66%, respectively. Cell cycle analysis indicated a high (43%) sub-G1 cell population in the H2O2-treated RSC96 cells compared with untreated cells (1%); whereas OGE pretreatment (150 and 200 μg/mL) of RSC96 cells significantly reduced the sub-G1 cells (7% and 8%, respectively). Furthermore, Western blot analysis revealed that OGE pretreatment inhibited H2O2-induced apoptotic protein caspase-3 activation and PARP cleavage, as well as it reversed Bax up-regulation and Bcl-2 down-regulation. The amelioration of OGE of cell stress and stress-induced apoptosis was proved by the HSP70 and HSP72 decrease. Conclusion: Our data suggest that OGE may minimize the cytotoxic effects of H2O2-induced SCs apoptosis by modulating the apoptotic pathway and could potentially supplement cell transplantation therapy. PMID:28824312

Cirrhosis induces apoptosis in renal tissue through intracellular oxidative stress.

PubMed

Silveira, Keli Cristina Simões da; Viau, Cassiana Macagnan; Colares, Josiane Raskopf; Saffi, Jenifer; Marroni, Norma Possa; Porawski, Marilene

2015-01-01

Renal failure is a frequent and serious complication in patients with decompensated cirrhosis. We aimed to evaluate the renal oxidative stress, cell damage and impaired cell function in animal model of cirrhosis. Secondary biliary cirrhosis was induced in rats by ligation of the common bile duct. We measured TBARS, ROS and mitochondrial membrane potential in kidney as markers of oxidative stress, and activities of the antioxidant enzymes. Relative cell viability was determined by trypan blue dye-exclusion assay. Annexin V-PE was used with a vital dye, 7-AAD, to distinguish apoptotic from necrotic cells and comet assay was used for determined DNA integrity in single cells. In bile duct ligation animals there was significant increase in the kidney lipoperoxidation and an increase of the level of intracellular ROS. There was too an increase in the activity of all antioxidant enzymes evaluated in the kidney. The percentage viability was above 90% in the control group and in bile duct ligation was 64.66% and the dominant cell death type was apoptosis. DNA damage was observed in the bile duct ligation. There was a decreased in the mitochondrial membrane potential from 71.40% ± 6.35% to 34.48% ± 11.40% in bile duct ligation. These results indicate that intracellular increase of ROS cause damage in the DNA and apoptosis getting worse the renal function in cirrhosis.

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

PubMed

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.

Protective effects of melatonin-loaded lipid-core nanocapsules on paraquat-induced cytotoxicity and genotoxicity in a pulmonary cell line.

PubMed

Charão, Mariele F; Baierle, Marília; Gauer, Bruna; Goethel, Gabriela; Fracasso, Rafael; Paese, Karina; Brucker, Natália; Moro, Angela M; Bubols, Guilherme B; Dias, Bruna B; Matte, Ursula S; Guterres, Silvia S; Pohlmann, Adriana R; Garcia, Solange C

2015-06-01

Many acute poisonings lack effective and specific antidotes. Due to both intentional and accidental exposures, paraquat (PQ) causes thousands of deaths annually, especially by pulmonary fibrosis. Melatonin (Mel), when incorporated into lipid-core nanocapsules (Mel-LNC), has enhanced antioxidant properties. The effects of such a formulation have not yet been studied with respect to mitigation of PQ- induced cytotoxicity and DNA damage. Here, we have tested whether Mel-LNC can ameliorate PQ-induced toxicity in the A549 alveolar epithelial cell line. Physicochemical characterization of the formulations was performed. Cellular uptake was measured using nanocapsules marked with rhodamine B. Cell viability was determined by the MTT assay and DNA damage was assessed by the comet assay. The enzyme-modified comet assay with endonuclease III (Endo III) and formamidopyrimidine glycosylase (FPG) were used to investigate oxidative DNA damage. Incubation with culture medium for 24h did not alter the granulometric profile of Mel-LNC formulations. Following treatment (3 and 24h), red fluorescence was detected around the cell nucleus, indicating internalization of the formulation. Melatonin solution (Mel), Mel-LNC, and LNC did not have significant effects on cell viability or DNA damage. Pre-treatment with Mel-LNC enhanced cell viability and showed a remarkable reduction in % DNA in tail compared to the PQ group; this was not observed in cells pre-treated with Mel. PQ induces oxidative DNA damage detected with the enzyme-modified comet assay. Mel-LNC reduced this damage more effectively than did Mel. In summary, Mel-LNC is better than Mel at protecting A549 cells from the cytotoxic and genotoxic effects of PQ. Copyright © 2015 Elsevier B.V. All rights reserved.

Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials

PubMed Central

Ibañez-Cabellos, José Santiago; de Cutanda, Sergio Bañuls-Sánchez; Berenguer-Pascual, Ester; Beltrán-García, Jesús; García-López, Eva; Pallardó, Federico V.; García-Giménez, José Luis; Pallarés-Sabater, Antonio; Zarzosa-López, Ignacio; Monterde, Manuel

2017-01-01

Human dental pulp stem cells (HDPSCs) are of special relevance in future regenerative dental therapies. Characterizing cytotoxicity and genotoxicity produced by endodontic materials is required to evaluate the potential for regeneration of injured tissues in future strategies combining regenerative and root canal therapies. This study explores the cytotoxicity and genotoxicity mediated by oxidative stress of three endodontic materials that are widely used on HDPSCs: a mineral trioxide aggregate (MTA-Angelus white), an epoxy resin sealant (AH-Plus cement), and an MTA-based cement sealer (MTA-Fillapex). Cell viability and cell death rate were assessed by flow cytometry. Oxidative stress was measured by OxyBlot. Levels of antioxidant enzymes were evaluated by Western blot. Genotoxicity was studied by quantifying the expression levels of DNA damage sensors such as ATM and RAD53 genes and DNA damage repair sensors such as RAD51 and PARP-1. Results indicate that AH-Plus increased apoptosis, oxidative stress, and genotoxicity markers in HDPSCs. MTA-Fillapex was the most cytotoxic oxidative stress inductor and genotoxic material for HDPSCs at longer times in preincubated cell culture medium, and MTA-Angelus was less cytotoxic and genotoxic than AH-Plus and MTA-Fillapex at all times assayed. PMID:28751918

Selenium Polysaccharide SPMP-2a from Pleurotus geesteranus Alleviates H2O2-Induced Oxidative Damage in HaCaT Cells

PubMed Central

Zhou, Cheng; Huang, Shoucheng

2017-01-01

Selenium- (Se-) enriched polysaccharide SPMP-2a was extracted and purified from Pleurotus geesteranus. SPMP-2a is a white flocculent polysaccharide and soluble in water, with a molecular weight of 3.32 × 104 Da. Fourier transform infrared spectroscopy spectral analysis indicated that it belongs to an acid Se polysaccharide with α-D-glucopyranoside bond. The effects of Se polysaccharide SPMP-2a in P. geesteranus against hydrogen peroxide- (H2O2-) induced oxidative damage in human keratinocytes (HaCaT) cells were evaluated further. Reduced cell viability and elevated apoptotic rates in H2O2-treated HaCaT cells were proven by MTT and flow cytometry assays. Hoechst 33342 staining revealed chromatin condensations in the nuclei of HaCaT cells. However, with the addition of SPMP-2a, cell viability improved, nuclear condensation declined, and cell apoptotic rates dropped significantly. Ultrastructural observation consistently revealed that treatments with SPMP-2a reduced the number of swollen and vacuolar mitochondria in the H2O2-treated cells compared with the controls. Furthermore, SPMP-2a increased the superoxide dismutase (SOD) and catalase (CAT) activities and reduced reactive oxygen species (ROS) content. Western blot analysis showed that SPMP-2a treatment effectively increased B-cell lymphoma 2 (Bcl-2) protein expression. Therefore, SPMP-2a could improve cellular antioxidant enzyme activities, reduce ROS levels, and increase Bcl-2 protein expression levels, thereby reducing cell apoptosis and protecting HaCaT cells from H2O2-induced oxidative damage. PMID:28293636

Protective Effect of Boric Acid on Oxidative DNA Damage In Chinese Hamster Lung Fibroblast V79 Cell Lines

PubMed Central

Yılmaz, Sezen; Ustundag, Aylin; Cemiloglu Ulker, Ozge; Duydu, Yalcın

2016-01-01

Objective Many studies have been published on the antioxidative effects of boric acid (BA) and sodium borates in in vitro studies. However, the boron (B) concentrations tested in these in vitro studies have not been selected by taking into account the realistic blood B concentrations in humans due to the lack of comprehensive epidemiological studies. The recently published epidemiological studies on B exposure conducted in China and Turkey provided blood B concentrations for both humans in daily life and workers under extreme exposure conditions in occupational setting. The results of these studies have made it possible to test antioxidative effects of BA in in vitro studies within the concentra- tion range relevant to humans. The aim of this study was to investigate the protective ef- fects of BA against oxidative DNA damage in V79 (Chinese hamster lung fibroblast) cells. The concentrations of BA tested for its protective effect was selected by taking the blood B concentrations into account reported in previously published epidemiological studies. Therefore, the concentrations of BA tested in this study represent the exposure levels for humans in both daily life and occupational settings. Materials and Methods In this experimental study, comet assay and neutral red uptake (NRU) assay methods were used to determinacy to toxicity and genotoxicity of BA and hydrogen peroxide (H2O2). Results The results of the NRU assay showed that BA was not cytotoxic within the tested concentrations (3, 10, 30, 100 and 200 µM). These non-cytotoxic concentrations were used for comet assay. BA pre-treatment significantly reduced (P<0.05, one-way ANOVA) the DNA damaging capacity of H2O2 at each tested BA concentrations in V79 cells. Conclusion Consequently, pre-incubation of V79 cells with BA has significantly reduced the H2O2-induced oxidative DNA damage in V79 cells. The protective effect of BA against oxidative DNA damage in V79 cells at 5, 10, 50, 100 and 200 μM (54, 108, 540, 1080, and 2161 ng/ml B equivalents) concentrations was proved in this in vitro study. PMID:26862534

Protective Effect of Boric Acid on Oxidative DNA Damage In Chinese Hamster Lung Fibroblast V79 Cell Lines.

PubMed

Yılmaz, Sezen; Ustundag, Aylin; Cemiloglu Ulker, Ozge; Duydu, Yalcın

2016-01-01

Many studies have been published on the antioxidative effects of boric acid (BA) and sodium borates in in vitro studies. However, the boron (B) concentrations tested in these in vitro studies have not been selected by taking into account the realistic blood B concentrations in humans due to the lack of comprehensive epidemiological studies. The recently published epidemiological studies on B exposure conducted in China and Turkey provided blood B concentrations for both humans in daily life and workers under extreme exposure conditions in occupational setting. The results of these studies have made it possible to test antioxidative effects of BA in in vitro studies within the concentra- tion range relevant to humans. The aim of this study was to investigate the protective ef- fects of BA against oxidative DNA damage in V79 (Chinese hamster lung fibroblast) cells. The concentrations of BA tested for its protective effect was selected by taking the blood B concentrations into account reported in previously published epidemiological studies. Therefore, the concentrations of BA tested in this study represent the exposure levels for humans in both daily life and occupational settings. In this experimental study, comet assay and neutral red uptake (NRU) assay methods were used to determinacy to toxicity and genotoxicity of BA and hydrogen peroxide (H2O2). The results of the NRU assay showed that BA was not cytotoxic within the tested concentrations (3, 10, 30, 100 and 200 µM). These non-cytotoxic concentrations were used for comet assay. BA pre-treatment significantly reduced (P<0.05, one-way ANOVA) the DNA damaging capacity of H2O2 at each tested BA concentrations in V79 cells. Consequently, pre-incubation of V79 cells with BA has significantly reduced the H2O2-induced oxidative DNA damage in V79 cells. The protective effect of BA against oxidative DNA damage in V79 cells at 5, 10, 50, 100 and 200 μM (54, 108, 540, 1080, and 2161 ng/ml B equivalents) concentrations was proved in this in vitro study.

Mitochondrial Dysfunction in Retinal Diseases

PubMed Central

Barot, Megha; Gokulgandhi, Mitan R.; Mitra, Ashim K.

2015-01-01

The mitochondrion is a vital intracellular organelle for retinal cell function and survival. There is growing confirmation to support an association between mitochondrial dysfunction and a number of retinal degenerations. Investigations have also unveiled mitochondrial genomic instability as one of the contributing factors for age-related retinal pathophysiology. This review highlights the role of mitochondrial dysfunction originating from oxidative stress in the etiology of retinal diseases including diabetic retinopathy, glaucoma and age-related macular degeneration (AMD). Moreover, mitochondrial DNA (mtDNA) damage associated with AMD due to susceptibility of mtDNA to oxidative damage and failure of mtDNA repair pathways is also highlighted in this review. The susceptibility of neural retina and retinal pigment epithelium (RPE) mitochondria to oxidative damage with ageing appears to be a major factor in retinal degeneration. It thus appears that the mitochondrion is a weak link in the antioxidant defenses of retinal cells. In addition, failure of mtDNA repair pathways can also specifically contribute towards pathogenesis of AMD. This review will further summarize the prospective role of mitochondria targeting therapeutic agents for the treatment of retinal disease. Mitochondria based drug targeting to diminish oxidative stress or promote repair of mtDNA damage may offer potential alternatives for the treatment of various retinal degenerative diseases. PMID:21978133

Mitochondrial dysfunction in retinal diseases.

PubMed

Barot, Megha; Gokulgandhi, Mitan R; Mitra, Ashim K

2011-12-01

The mitochondrion is a vital intracellular organelle for retinal cell function and survival. There is growing confirmation to support an association between mitochondrial dysfunction and a number of retinal degenerations. Investigations have also unveiled mitochondrial genomic instability as one of the contributing factors for age-related retinal pathophysiology. This review highlights the role of mitochondrial dysfunction originating from oxidative stress in the etiology of retinal diseases including diabetic retinopathy, glaucoma and age-related macular degeneration (AMD). Moreover, mitochondrial DNA (mtDNA) damage associated with AMD due to susceptibility of mtDNA to oxidative damage and failure of mtDNA repair pathways is also highlighted in this review. The susceptibility of neural retina and retinal pigment epithelium (RPE) mitochondria to oxidative damage with ageing appears to be a major factor in retinal degeneration. It thus appears that the mitochondrion is a weak link in the antioxidant defenses of retinal cells. In addition, failure of mtDNA repair pathways can also specifically contribute towards pathogenesis of AMD. This review will further summarize the prospective role of mitochondria targeting therapeutic agents for the treatment of retinal disease. Mitochondria based drug targeting to diminish oxidative stress or promote repair of mtDNA damage may offer potential alternatives for the treatment of various retinal degenerative diseases.

DNA Damage and Repair in Schizophrenia and Autism: Implications for Cancer Comorbidity and Beyond

PubMed Central

Markkanen, Enni; Meyer, Urs; Dianov, Grigory L.

2016-01-01

Schizophrenia and autism spectrum disorder (ASD) are multi-factorial and multi-symptomatic psychiatric disorders, each affecting 0.5%–1% of the population worldwide. Both are characterized by impairments in cognitive functions, emotions and behaviour, and they undermine basic human processes of perception and judgment. Despite decades of extensive research, the aetiologies of schizophrenia and ASD are still poorly understood and remain a significant challenge to clinicians and scientists alike. Adding to this unsatisfactory situation, patients with schizophrenia or ASD often develop a variety of peripheral and systemic disturbances, one prominent example of which is cancer, which shows a direct (but sometimes inverse) comorbidity in people affected with schizophrenia and ASD. Cancer is a disease characterized by uncontrolled proliferation of cells, the molecular origin of which derives from mutations of a cell’s DNA sequence. To counteract such mutations and repair damaged DNA, cells are equipped with intricate DNA repair pathways. Oxidative stress, oxidative DNA damage, and deficient repair of oxidative DNA lesions repair have been proposed to contribute to the development of schizophrenia and ASD. In this article, we summarize the current evidence of cancer comorbidity in these brain disorders and discuss the putative roles of oxidative stress, DNA damage and DNA repair in the aetiopathology of schizophrenia and ASD. PMID:27258260

Lycium barbarum polysaccharide protects human keratinocytes against UVB-induced photo-damage.

PubMed

Li, Huaping; Li, Zhenjie; Peng, Liqian; Jiang, Na; Liu, Qing; Zhang, Erting; Liang, Bihua; Li, Runxiang; Zhu, Huilan

2017-02-01

Ultraviolet B (UVB) irradiation plays a key role in skin damage, which induces oxidative and inflammatory damages, thereby causing photoaging or photocarcinogenesis. Lycium barbarum polysaccharide (LBP), the most biologically active fraction of wolfberry, possesses significant antioxidative and anti-inflammatory effects on multiple tissues. In the present study, the photoprotective effects and potential underlying molecular mechanisms of LBP against UVB-induced photo-damage were investigated in immortalized human keratinocytes (HaCaT cells). The data indicated that pretreatment with LBP significantly attenuated UVB-induced decrease in cell viability, increase in ROS production and DNA damage. LBP also significantly suppressed UVB-induced p38 MAPK activation, and subsequently reversed caspase-3 activation and MMP-9 expression. Notably, LBP was found to induce Nrf2 nuclear translocation and increase the expression of Nrf2-dependent ARE target genes. Furthermore, the protective effects of LBP were abolished by siRNA-mediated Nrf2 silencing. These results showed that the antioxidant LBP could partially protect against UVB irradiation-induced photo-damage through activation of Nrf2/ARE pathway, thereby scavenging ROS and reducing DNA damage, and subsequently suppressing UVB-induced p38 MAP pathway. Thus, LBP can be potentially used for skincare against oxidative damage from environmental insults.

HaCaT anchorage blockade leads to oxidative stress, DNA damage and DNA methylation changes.

PubMed

da Silva, Rodrigo A; Sammartino Mariano, Flavia; Planello, Aline C; Line, Sergio R P; de Souza, Ana Paula

2015-07-01

Cell adhesion plays an important role in neoplastic transformation. Thus, anchorage-independent growth and epithelial-mesenchymal transition, which are features associated to anoikis-resistance, are vital steps in cancer progression and metastatic colonization. Cell attachment loss may induce intracellular oxidative stress, which triggers DNA damage as methylation changes. HaCaT lineage cells were submitted to periods of 1, 3, 5 and 24 h of anchorage blockage with the purpose of study of oxidative stress effect on changes in the DNA methylation pattern, derived from attachment blockade. Through this study, HaCaT anchorage blockage-induced oxidative stress was reported to mediate alterations in global DNA methylation changes and into TP53 gene promoter pattern during anoikis-resistance acquisition. Furthermore, at the first experimental time-periods (1, 3 and 5 h), genome hypermethylation was found; however, genome hypomethylation was observed in later time-periods (24 h) of attachment impediment. The TP 53 methylation analyses were performed after 24 h of replated anoikis-resistance cells and same methylation pattern was observed, occurring an early (1 and 3 h) hypermethylation that was followed by late (5 and 24 h) hypomethylation. However, LINE-1, a marker of genomic instability, was perceived in time-dependent hypomethylation. The mRNA levels of the DNMTs enzymes were influenced by cell attachment blockage, but non-conclusive results were obtained in order to match DNMTs transcription to pattern methylation results. In conclusion, DNA damage was found, leaded by oxidative stress that has come up from HaCaT anchorage blockade, which rises a global genome hypomethylation tendency as consequence, which might denote genomic instability.

Mitochondrial Modulation by Epigallocatechin 3-Gallate Ameliorates Cisplatin Induced Renal Injury through Decreasing Oxidative/Nitrative Stress, Inflammation and NF-kB in Mice

PubMed Central

Wang, Xueping; Wang, Ping; Fu, Guanghou; Meng, Hongzhou; Wang, Yimin; Jin, Baiye

2015-01-01

Cancer chemotherapy drug cisplatin is known for its nephrotoxicity. The aim of this study is to investigate whether Epigallocatechin 3-Gallate (EGCG) can reduce cisplatin mediated side effect in kidney and to understand its mechanism of protection against tissue injury. We used a well-established 3-day cisplatin induced nephrotoxicity mice model where EGCG were administered. EGCG is a major active compound in Green Tea and have strong anti-oxidant and anti-inflammatory properties. EGCG protected against cisplatin induced renal dysfunction as measured by serum creatinine and blood urea nitrogen (BUN). EGCG improved cisplatin induced kidney structural damages such as tubular dilatation, cast formation, granulovaculoar degeneration and tubular cell necrosis as evident by PAS staining. Cisplatin induced kidney specific mitochondrial oxidative stress, impaired activities of mitochondrial electron transport chain enzyme complexes, impaired anti-oxidant defense enzyme activities such as glutathione peroxidase (GPX) and manganese superoxide dismutase (MnSOD) in mitochondria, inflammation (tumor necrosis factor α and interleukin 1β), increased accumulation of NF-κB in nuclear fraction, p53 induction, and apoptotic cell death (caspase 3 activity and DNA fragmentation). Treatment of mice with EGCG markedly attenuated cisplatin induced mitochondrial oxidative/nitrative stress, mitochondrial damages to electron transport chain activities and antioxidant defense enzyme activities in mitochondria. These mitochondrial modulations by EGCG led to protection mechanism against cisplatin induced inflammation and apoptotic cell death in mice kidney. As a result, EGCG improved renal function in cisplatin mediated kidney damage. In addition to that, EGCG attenuated cisplatin induced apoptotic cell death and mitochondrial reactive oxygen species (ROS) generation in human kidney tubular cell line HK-2. Thus, our data suggest that EGCG may represent new promising adjunct candidate for cisplatin. PMID:25875356

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preta, Giulio; Klark, Rainier de; Chakraborti, Shankhamala

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 eventmore » 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.« less

Food-Derived Antioxidant Polysaccharides and Their Pharmacological Potential in Neurodegenerative Diseases

PubMed Central

Li, Haifeng; Ding, Fei; Xiao, Lingyun; Shi, Ruona; Wang, Hongyu; Han, Wenjing

2017-01-01

Oxidative stress is known to impair architecture and function of cells, which may lead to various chronic diseases, and therefore therapeutic and nutritional interventions to reduce oxidative damages represent a viable strategy in the amelioration of oxidative stress-related disorders, including neurodegenerative diseases. Over the past decade, a variety of natural polysaccharides from functional and medicinal foods have attracted great interest due to their antioxidant functions such as scavenging free radicals and reducing oxidative damages. Interestingly, these antioxidant polysaccharides are also found to attenuate neuronal damages and alleviate cognitive and motor decline in a range of neurodegenerative models. It has recently been established that the neuroprotective mechanisms of polysaccharides are related to oxidative stress-related pathways, including mitochondrial function, antioxidant defense system and pathogenic protein aggregation. Here, we first summarize the current status of antioxidant function of food-derived polysaccharides and then attempt to appraise their anti-neurodegeneration activities. PMID:28753972

Continuous in vitro exposure of intestinal epithelial cells to E171 food additive causes oxidative stress, inducing oxidation of DNA bases but no endoplasmic reticulum stress.

PubMed

Dorier, Marie; Béal, David; Marie-Desvergne, Caroline; Dubosson, Muriel; Barreau, Frédérick; Houdeau, Eric; Herlin-Boime, Nathalie; Carriere, Marie

2017-08-01

The whitening and opacifying properties of titanium dioxide (TiO 2 ) are commonly exploited when it is used as a food additive (E171). However, the safety of this additive can be questioned as TiO 2 nanoparticles (TiO 2 -NPs) have been classed at potentially toxic. This study aimed to shed some light on the mechanisms behind the potential toxicity of E171 on epithelial intestinal cells, using two in vitro models: (i) a monoculture of differentiated Caco-2 cells and (ii) a coculture of Caco-2 with HT29-MTX mucus-secreting cells. Cells were exposed to E171 and two different types of TiO 2 -NPs, either acutely (6-48 h) or repeatedly (three times a week for 3 weeks). Our results confirm that E171 damaged these cells, and that the main mechanism of toxicity was oxidation effects. Responses of the two models to E171 were similar, with a moderate, but significant, accumulation of reactive oxygen species, and concomitant downregulation of the expression of the antioxidant enzymes catalase, superoxide dismutase and glutathione reductase. Oxidative damage to DNA was detected in exposed cells, proving that E171 effectively induces oxidative stress; however, no endoplasmic reticulum stress was detected. E171 effects were less intense after acute exposure compared to repeated exposure, which correlated with higher Ti accumulation. The effects were also more intense in cells exposed to E171 than in cells exposed to TiO 2 -NPs. Taken together, these data show that E171 induces only moderate toxicity in epithelial intestinal cells, via oxidation.

Lemon balm extract (Melissa officinalis, L.) promotes melanogenesis and prevents UVB-induced oxidative stress and DNA damage in a skin cell model.

PubMed

Pérez-Sánchez, Almudena; Barrajón-Catalán, Enrique; Herranz-López, María; Castillo, Julián; Micol, Vicente

2016-11-01

Solar ultraviolet (UV) radiation is one of the main causes of a variety of cutaneous disorders, including photoaging and skin cancer. Its UVB component (280-315nm) leads to oxidative stress and causes inflammation, DNA damage, p53 induction and lipid and protein oxidation. Recently, an increase in the use of plant polyphenols with antioxidant and anti-inflammatory properties has emerged to protect human skin against the deleterious effects of sunlight. This study evaluates the protective effects of lemon balm extract (LBE) (Melissa Officinalis, L) and its main phenolic compound rosmarinic acid (RA) against UVB-induced damage in human keratinocytes. The LBE composition was determined by HPLC analysis coupled to photodiode array detector and ion trap mass spectrometry with electrospray ionization (HPLC-DAD-ESI-IT-MS/MS). Cell survival, ROS generation and DNA damage were determined upon UVB irradiation in the presence of LBE. The melanogenic capacity of LBE was also determined. RA and salvianolic acid derivatives were the major compounds, but caffeic acid and luteolin glucuronide were also found in LBE. LBE and RA significantly increased the survival of human keratinocytes upon UVB radiation, but LBE showed a stronger effect. LBE significantly decreased UVB-induced intracellular ROS production. Moreover, LBE reduced UV-induced DNA damage and the DNA damage response (DDR), which were measured as DNA strand breaks in the comet assay and histone H2AX activation, respectively. Finally, LBE promoted melanogenesis in the cell model. These results suggest that LBE may be considered as a candidate for the development of oral/topical photoprotective ingredients against UVB-induced skin damage. Copyright © 2016 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

[Action mechanism of electroacupuncture at stomach meridian acupoints for oxidative damage in rats with gastric ulcer].

PubMed

Yang, Zongbao; Wang, Yadong; Liu, Qiong; Liu, Mi; Chen, Huijuan; Chang, Xiaorong

2016-06-12

To observe the effects of electroacupuncture (EA) at stomach meridian acupoints on expression of oxidation damage factors in serum and gastric mucosal cells in rats with gastric ulcer, and to explore the mechanism of EA at stomach meridian acupoints for oxidative damage in rats with gastric ulcer. Forty clean-grade SD rats were randomly divided into a normal group, a model group, a stomach meridian group and a gallbladder meridian group, ten rats in each one. Except the normal group, rats in the remaining groups were applied the restraint-cold stress method to establish the model of gastric ulcer. Rats in the normal group and model group received no treatment; rats in the stomach meridian group were treated with EA at "Liangmen" (ST 21) and "Zusanli" (ST 36); rats in the gallbladder meridian group were treated with EA at "Riyue" (GB 24) and "Yanglingquan" (GB 34). The EA was given for 30 min, once a day for 7 days totally. The change of gastric mucosal morphology was observed by routine light microscope; enzyme linked immunosorbent assay was used to detect the expressions of malondialdehyde (MDA), glutathione peroxidase (GSH-px) and tumor necrosis factor-α (TNF-α), interleukin-2(IL-2), interleukin-6(IL-6) in serum and gastric mucosal cells of rats. After treatment, compared with the model group, the gastric mucosal damage index was decreased in the stomach meridian group and gallbladder meridian group (both P <0.05), the expressions of MDA, TNF-α, IL-2 and IL-6 in serum and gastric mucosal cells were significantly decreased in the stomach meridian group (all P <0.01), but the contents of GSH-Px in serum and gastric mucosal cells were increased significantly (both P <0.01). Compared with the gallbladder meridian group, the gastric mucosal damage index as well as the expressions of MDA,TNF-α, IL-2 and IL-6 in serum and gastric mucosal cells were significantly decreased in the stomach meridian group rats ( P <0.05, P <0.01), and the contents of GSH-px in serum and gastric mucosal cells were increased significantly (both P <0.01). EA at stomach meridian acupoints is likely to inhibit the expressions of oxidative damage factors to promote the repair of gastric mucosal injury, which indicates the correlation between meridians and zang-fu .

Diabetes Impairs the Vascular Recruitment of Normal Stem Cells by Oxidant Damage, Reversed by Increases in pAMPK, Heme Oxygenase-1, and Adiponectin

PubMed Central

Sambuceti, Gianmario; Morbelli, Silvia; Vanella, Luca; Kusmic, Claudia; Marini, Cecilia; Massollo, Michela; Augeri, Carla; Corselli, Mirko; Ghersi, Chiara; Chiavarina, Barbara; Rodella, Luigi F; L'Abbate, Antonio; Drummond, George; Abraham, Nader G; Frassoni, Francesco

2009-01-01

Background Atherosclerosis progression is accelerated in diabetes mellitus (DM) by either direct endothelial damage or reduced availability and function of endothelial progenitor cells (EPCs). Both alterations are related to increased oxidant damage. Aim We examined if DM specifically impairs vascular signaling, thereby reducing the recruitment of normal EPCs, and if increases in antioxidant levels by induction of heme oxygenase-1 (HO-1) can reverse this condition. Methods Control and diabetic rats were treated with the HO-1 inducer cobalt protoporphyrin (CoPP) once a week for 3 weeks. Eight weeks after the development of diabetes, EPCs harvested from the aorta of syngenic inbred normal rats and labeled with technetium-99m-exametazime were infused via the femoral vein to estimate their blood clearance and aortic recruitment. Circulating endothelial cells (CECs) and the aortic expression of thrombomodulin (TM), CD31, and endothelial nitric oxide synthase (eNOS) were used to measure endothelial damage. Results DM reduced blood clearance and aortic recruitment of EPCs. Both parameters were returned to control levels by CoPP treatment without affecting EPC kinetics in normal animals. These abnormalities of EPCs in DM were paralleled by reduced serum adiponectin levels, increased numbers of CECs, reduced endothelial expression of phosphorylated eNOS, and reduced levels of TM, CD31, and phosphorylated AMP-activated protein kinase (pAMPK). CoPP treatment restored all of these parameters to normal levels. Conclusion Type II DM and its related oxidant damage hamper the interaction between the vascular wall and normal EPCs by mechanisms that are, at least partially, reversed by the induction of HO-1 gene expression, adiponectin, and pAMPK levels. PMID:19038792

Genomic and post-genomic effects of anti-glaucoma drugs preservatives in trabecular meshwork.

PubMed

Izzotti, Alberto; La Maestra, Sebastiano; Micale, Rosanna Tindara; Longobardi, Maria Grazia; Saccà, Sergio Claudio

2015-02-01

Oxidative stress plays an important role in glaucoma. Some preservatives of anti-glaucoma drugs, commonly used in glaucoma therapy, can prevent or induce oxidative stress in the trabecular meshwork. The aim of this study is to evaluate cellular and molecular damage induced in trabecular meshwork by preservatives contained in anti-glaucoma drugs. Cell viability (MTT test), DNA fragmentation (Comet test), oxidative DNA damage (8-oxo-dG), and gene expression (cDNA microarray) have been evaluated in trabecular meshwork specimens and in human trabecular meshwork cells treated with benzalkonium chloride, polyQuad, purite, and sofzia-like mixture. Moreover, antimicrobial effectiveness and safety of preservative contents in drugs was tested. In ex vivo experiments, benzalkonium chloride and polyQuad induced high level of DNA damage in trabecular meshwork specimens, while the effect of purite and sofzia were more attenuated. The level of DNA fragmentation induced by benzalkonium chloride was 2.4-fold higher in subjects older than 50 years than in younger subjects. Benzalkonium chloride, and polyQuad significantly increased oxidative DNA damage as compared to sham-treated specimens. Gene expression was altered by benzalkonium chloride, polyQuad, and purite but not by sofzia. In in vitro experiments, benzalkonium chloride and polyQuad dramatically decreased trabecular meshwork cell viability, increased DNA fragmentation, and altered gene expression. A lesser effect was also exerted by purite and sofzia. Genes targeted by these alterations included Fas and effector caspase-3. The efficacy of the preservatives in inhibiting bacterial growth increased the adverse effects in trabecular meshwork in terms of DNA damage and alteration of gene expression. Presented data indicates the delicate balance between efficacy and safety of drug preservatives as not yet optimized. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of Cigarette Smoking on Concentrations of Cadmium and Lead and on the Oxidative Damage in Human Spermatozoa

NASA Astrophysics Data System (ADS)

Kiziler, Ali Riza; Aydemir, Birsen; Onaran, Ilhan; Alici, Bülent; Özkara, Hamdi; Akyolcu, Mehmet Can

2007-04-01

Cigarette smoking induced a significant oxidant effect to free radical-related male infertility. Semen and blood obtained from 50 subfertile men (n=26 smokers, n=24 nonsmokers) and from 45 fertile men (n=23 smokers, n=22 nonsmokers) volunteers were examined. The levels of ROS, MDA and protein carbonyls were significantly increased in smokers subfertile men. The results indicate that Cd and Pb levels of smoking subfertile men in seminal plasma and spermatozoa could affect semen quality and oxidative damage in human sperm cells.

Zinc oxide nanoparticles induce rat retinal ganglion cell damage through bcl-2, caspase-9 and caspase-12 pathways.

PubMed

Guo, Dadong; Bi, Hongsheng; Wu, Qiuxin; Wang, Daoguang; Cui, Yan

2013-06-01

Nanomaterials, including zinc oxide (ZnO) nanoparticles, are being developed for a variety of commercial products. Recent reports showed that cells exposed to ZnO nanoparticles produced severe cytotoxicity accompanied by oxidative stress and genotoxicity. To understand the possible mechanism underlying oxidative stress of ZnO nanoparticles, the present investigation focused on the direct bioactivity of ZnO nanoparticles using a rat retinal ganglion cell (RGC-5) culture. At concentrations relevant to those used in vitro exposure of RGC-5 cells to ZnO nanoparticles, it was found that ZnO nanoparticles could inhibit cell proliferation in time- and concentration-dependent manners. Meanwhile, cell cycle arrest of S and G2/M phases occurred in RGC-5 cells induced by ZnO nanoparticles. Moreover, our results also demonstrated that the overproduction of reactive oxygen species (ROS) and elevated level of caspase-12 as well as decreased levels of bcl-2 and caspase-9 occurred after treatment with different concentrations of ZnO nanoparticles when compared to those in untreated cells. In summary, our findings suggest that ZnO nanoparticles could lead to the over generations of ROS and caspase-12 as well as decreased levels of bcl-2 and caspase-9. These results indicate that bcl-2, caspase-9 and caspase-12 may play significant roles in ZnO nanoparticle-induced RGC-5 cell damage.

Hepatic protection and anticancer activity of curcuma: A potential chemopreventive strategy against hepatocellular carcinoma

PubMed Central

LI, YAN; SHI, XUE; ZHANG, JINGWEN; ZHANG, XIANG; MARTIN, ROBERT C.G.

2014-01-01

Malignant transformation of hepatocellular carcinoma (HCC) occurs through repetitive liver injury in a context of inflammation and oxidative DNA damage. A spectrum of natural sesquiterpenoids from curcuma oil has displayed anti-oxidant, anti-inflammatory and anti-carcinogenic properties. The aim of the study was to investigate the hepatoprotective and anti-HCC effects of curcuma oil in vivo and in vitro. Mice were pretreated with curcuma oil (100 mg/kg) for 3 days, then treated with Concanavalin A (30 mg/kg). The hepatic tissue was evaluated for histology, CD4+ cell, interferon-γ, apoptosis, lipid peroxidation, 8-hydroxy-deoxyguanosine and MnSOD. C57L/J mice were treated with curcuma oil and 107 Hepa1-6 cells directly inoculated into liver lobes. The effects of curcuma oil on cell growth and cell death were evaluated. In addition, MnSOD, HSP60, catalase, NF-κB and caspase-3 were also investigated in the Hepa1-6 cells treated with curcuma oil. Pretreatment with curcuma oil significantly attenuates inflammation and oxidative damage by Concanavalin A. Treatment with curcuma oil can decrease the incidence of HCC. Curcuma oil inhibits cell growth and induces cell death in Hepa1-6 cells. Curcuma protected mice with hepatic injury from inflammatory and oxidative stress. Curcuma oil can inhibit hepatoma cell growth in vivo and in vitro. PMID:24270742

Protective role of arzanol against lipid peroxidation in biological systems.

PubMed

Rosa, Antonella; Pollastro, Federica; Atzeri, Angela; Appendino, Giovanni; Melis, M Paola; Deiana, Monica; Incani, Alessandra; Loru, Debora; Dessì, M Assunta

2011-01-01

This study examines the protective effect of arzanol, a pyrone-phloroglucinol etherodimer from Helichrysum italicum subsp. microphyllum, against the oxidative modification of lipid components induced by Cu(2+) ions in human low density lipoprotein (LDL) and by tert-butyl hydroperoxide (TBH) in cell membranes. LDL pre-treatment with arzanol significantly preserved lipoproteins from oxidative damage at 2h of oxidation, and showed a remarkable protective effect on the reduction of polyunsaturated fatty acids and cholesterol levels, inhibiting the increase of oxidative products (conjugated dienes fatty acids hydroperoxides, 7β-hydroxycholesterol, and 7-ketocholesterol). Arzanol, at non-cytotoxic concentrations, exerted a noteworthy protection on TBH-induced oxidative damage in a line of fibroblasts derived from monkey kidney (Vero cells) and in human intestinal epithelial cells (Caco-2), decreasing, in both cell lines, the formation of oxidative products (hydroperoxides and 7-ketocholesterol) from the degradation of unsaturated fatty acids and cholesterol. The cellular uptake and transepithelial transport of the compound were also investigated in Caco-2 cell monolayers. Arzanol appeared to accumulate in Caco-2 epithelial cells. This phenol was able to pass through the intestinal Caco-2 monolayers, the apparent permeability coefficients (P(app)) in the apical-to-basolateral and basolateral-to-apical direction at 2h were 1.93±0.36×10(-5) and 2.20±0.004×10(-5)cm/s, respectively, suggesting a passive diffusion pathway. The results of the work qualify arzanol as a potent natural antioxidant with a protective effect against lipid oxidation in biological systems. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Reactive Oxygen Species (ROS)-Activated ATM-Dependent Phosphorylation of Cytoplasmic Substrates Identified by Large-Scale Phosphoproteomics Screen*

PubMed Central

Kozlov, Sergei V.; Waardenberg, Ashley J.; Engholm-Keller, Kasper; Arthur, Jonathan W.; Graham, Mark E.; Lavin, Martin

2016-01-01

Ataxia-telangiectasia, mutated (ATM) protein plays a central role in phosphorylating a network of proteins in response to DNA damage. These proteins function in signaling pathways designed to maintain the stability of the genome and minimize the risk of disease by controlling cell cycle checkpoints, initiating DNA repair, and regulating gene expression. ATM kinase can be activated by a variety of stimuli, including oxidative stress. Here, we confirmed activation of cytoplasmic ATM by autophosphorylation at multiple sites. Then we employed a global quantitative phosphoproteomics approach to identify cytoplasmic proteins altered in their phosphorylation state in control and ataxia-telangiectasia (A-T) cells in response to oxidative damage. We demonstrated that ATM was activated by oxidative damage in the cytoplasm as well as in the nucleus and identified a total of 9,833 phosphorylation sites, including 6,686 high-confidence sites mapping to 2,536 unique proteins. A total of 62 differentially phosphorylated peptides were identified; of these, 43 were phosphorylated in control but not in A-T cells, and 19 varied in their level of phosphorylation. Motif enrichment analysis of phosphopeptides revealed that consensus ATM serine glutamine sites were overrepresented. When considering phosphorylation events, only observed in control cells (not observed in A-T cells), with predicted ATM sites phosphoSerine/phosphoThreonine glutamine, we narrowed this list to 11 candidate ATM-dependent cytoplasmic proteins. Two of these 11 were previously described as ATM substrates (HMGA1 and UIMCI/RAP80), another five were identified in a whole cell extract phosphoproteomic screens, and the remaining four proteins had not been identified previously in DNA damage response screens. We validated the phosphorylation of three of these proteins (oxidative stress responsive 1 (OSR1), HDGF, and ccdc82) as ATM dependent after H2O2 exposure, and another protein (S100A11) demonstrated ATM-dependence for translocation from the cytoplasm to the nucleus. These data provide new insights into the activation of ATM by oxidative stress through identification of novel substrates for ATM in the cytoplasm. PMID:26699800

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

PubMed Central

Grindel, Annemarie; Guggenberger, Bianca; Eichberger, Lukas; Pöppelmeyer, Christina; Gschaider, Michaela; Tosevska, Anela; Mare, George; Briskey, David; Brath, Helmut; Wagner, Karl-Heinz

2016-01-01

Background 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. Methods 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. Results 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. Conclusion 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 treatment with regular health checks in T2DM patients in Austria. PMID:27598300

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

PubMed

Grindel, Annemarie; Guggenberger, Bianca; Eichberger, Lukas; Pöppelmeyer, Christina; Gschaider, Michaela; Tosevska, Anela; Mare, George; Briskey, David; Brath, Helmut; Wagner, Karl-Heinz

2016-01-01

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 treatment with regular health checks in T2DM patients in Austria.

Effect of hypothermia on doxorubicin-induced cardiac myoblast signaling and cell death.

PubMed

L'Ecuyer, Thomas J; Aggarwal, Sanjeev; Zhang, Jiang Ping; Van der Heide, Richard S

2012-01-01

Anthracyclines (AC) are useful chemotherapeutic agents whose principal limitation is cardiac toxicity, which may progress to heart failure, transplantation or even death. We have shown that this toxicity involves oxidative stress-induced activation of the DNA damage pathway. Hypothermia has been shown to be protective against other diseases involving oxidative stress but has not been studied in models of AC toxicity. In the current experiments, H9C2 cardiac myoblasts were treated with varying concentrations of the AC doxorubicin (DOX) during normothermia (37°C) or mild hypothermia (35°C). Total cell death was assayed using trypan blue exclusion and apoptosis by terminal deoxynucleotidyl transferase-mediated deoxyuridine-biotin nick end labeling (TUNEL) staining. Oxidative stress was assayed using the fluorescent indicator 2'7'-dichlorofluorescein diacetate. DNA damage pathway activation was assayed by immunostaining for H2AX and p53. Mitochondrial membrane potential was assayed by JC-1 staining. At all concentrations of DOX examined (1, 2.5 and 5 μM), hypothermia reduced oxidative stress, activation of H2AX and p53, loss of mitochondrial membrane potential and total and apoptotic cell death (P=.001-.03 for each observation). The reduction of oxidative stress-induced activation of the DNA damage pathway and consequent cell death by mild hypothermia supports a possible protective role to reduce the clinical impact of DOX-induced cardiac toxicity. Such an approach may allow expanded use of these effective chemotherapeutic agents to increase cancer cure rates. Copyright © 2012 Elsevier Inc. All rights reserved.

Ascorbic Acid Repletion: A Possible Therapy for Diabetic Macular Edema?

PubMed Central

May, James M.

2016-01-01

Macular edema poses a significant risk for visual loss in persons with diabetic retinopathy. It occurs when plasma constituents and fluid leak out of damaged retinal microvasculature in the area of the macula, causing loss of central vision. Apoptotic loss of pericytes surrounding capillaries is perhaps the earliest feature of diabetic vascular damage in the macula, which is also associated with dysfunction of the endothelium and loss of the otherwise very tight endothelial permeability barrier. Increased oxidative stress is a key feature of damage to both cell types, mediated by excess superoxide from glucose-induced increases in mitochondrial metabolism, as well as by activation of the receptor for advanced glycation end products (RAGE). The latter in turn activates multiple pathways, some of which lead to increased oxidative stress, such as those involving NF-κB, NADPH oxidase, and endothelial nitric oxide synthase. Such cellular oxidative stress is associated with low cellular and plasma ascorbic acid levels in many subjects with diabetes in poor glycemic control. Whether repletion of low ascorbate in retinal endothelium and pericytes might help to prevent diabetic macular edema is unknown. However, cell culture studies show that the vitamin prevents high-glucose and RAGE-induced apoptosis in both cell types, that it preserves nitric oxide generated by endothelial cells, and that it tightens the leaky endothelial permeability barrier. Although these findings need to be confirmed in pre-clinical animal studies, it is worth considering clinical trials to determine whether adequate ascorbate repletion is possible and whether it might help to delay or even reverse early diabetic macular edema. PMID:26898503

Carbon monoxide alleviates lipopolysaccharide-induced oxidative stress injury through suppressing the expression of Fis1 in NR8383 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Jia; Yu, Jian-bo, E-mail: yujianbo11@126.com; Liu, Wei

Acute respiratory distress syndrome (ARDS) is one of the most devastating complications of sepsis lacking of effective therapy. Mitochondrial dynamics undergoing continuous fusion and fission play a crucial role in mitochondrial structure and function. Fis1, as a small protein located on the outer membrane of mitochondria, has been thought to be an important protein mediated mitochondrial fission. During ARDS, alveolar macrophages suffer from increased oxidative stress and apoptosis, and also accompanied by disrupted mitochondrial dynamics. In addition, as one of the products of heme degradation catalyzed by heme oxygenase, carbon monoxide (CO) possesses powerful protective properties in vivo or inmore » vitro models, such as anti-inflammatory, antioxidant and anti-apoptosis function. However, there is little evidence that CO alleviates oxidative stress damage through altering mitochondrial fission in alveolar macrophages. In the present study, our results showed that CO increased cell vitality, improved mitochondrial SOD activity, reduced reactive oxygen species (ROS) production and inhibited cell apoptosis in NR8383 exposed to LPS. Meanwhile, CO decreased the expression of Fis1, increased mitochondrial membrane potential and sustained elongation of mitochondria in LPS-incubated NR8383. Overall, our study underscored a critical role of CO in suppressing the expression of Fis1 and alleviating LPS- induced oxidative stress damage in alveolar macrophages. - Highlights: • LPS exposure triggered cell injury in NR8383. • CO alleviated LPS-induced oxidative stress damage in alveolar macrophages. • CO inhibited Fis1 levels and improved mitochondrial function in LPS-induced NR8383.« less

Fluoride induces oxidative damage and SIRT1/autophagy through ROS-mediated JNK signaling.

PubMed

Suzuki, Maiko; Bandoski, Cheryl; Bartlett, John D

2015-12-01

Fluoride is an effective caries prophylactic, but at high doses can also be an environmental health hazard. Acute or chronic exposure to high fluoride doses can result in dental enamel and skeletal and soft tissue fluorosis. Dental fluorosis is manifested as mottled, discolored, porous enamel that is susceptible to dental caries. Fluoride induces cell stress, including endoplasmic reticulum stress and oxidative stress, which leads to impairment of ameloblasts responsible for dental enamel formation. Recently we reported that fluoride activates SIRT1 and autophagy as an adaptive response to protect cells from stress. However, it still remains unclear how SIRT1/autophagy is regulated in dental fluorosis. In this study, we demonstrate that fluoride exposure generates reactive oxygen species (ROS) and the resulting oxidative damage is counteracted by SIRT1/autophagy induction through c-Jun N-terminal kinase (JNK) signaling in ameloblasts. In the mouse-ameloblast-derived cell line LS8, fluoride induced ROS, mitochondrial damage including cytochrome-c release, up-regulation of UCP2, attenuation of ATP synthesis, and H2AX phosphorylation (γH2AX), which is a marker of DNA damage. We evaluated the effects of the ROS inhibitor N-acetylcysteine (NAC) and the JNK inhibitor SP600125 on fluoride-induced SIRT1/autophagy activation. NAC decreased fluoride-induced ROS generation and attenuated JNK and c-Jun phosphorylation. NAC decreased SIRT1 phosphorylation and formation of the autophagy marker LC3II, which resulted in an increase in the apoptosis mediators γH2AX and cleaved/activated caspase-3. SP600125 attenuated fluoride-induced SIRT1 phosphorylation, indicating that fluoride activates SIRT1/autophagy via the ROS-mediated JNK pathway. In enamel organs from rats or mice treated with 50, 100, or 125 ppm fluoride for 6 weeks, cytochrome-c release and the DNA damage markers 8-oxoguanine, p-ATM, and γH2AX were increased compared to those in controls (0 ppm fluoride). These results suggest that fluoride-induced ROS generation causes mitochondrial damage and DNA damage, which may lead to impairment of ameloblast function. To counteract this impairment, SIRT1/autophagy is induced via JNK signaling to protect cells/ameloblasts from fluoride-induced oxidative damage that may cause dental fluorosis. Copyright © 2015 Elsevier Inc. All rights reserved.

Fluoride induces oxidative damage and SIRT1/autophagy through ROS-mediated JNK signaling

PubMed Central

Suzuki, Maiko; Bandoski, Cheryl; Bartlett, John D.

2015-01-01

Fluoride is an effective caries prophylactic, but at high doses can also be an environmental health hazard. Acute or chronic exposure to high fluoride doses can result in dental enamel and skeletal and soft tissue fluorosis. Dental fluorosis is manifested as mottled, discolored, porous enamel that is susceptible to dental caries. Fluoride induces cell stress, including endoplasmic reticulum stress and oxidative stress, which leads to impairment of ameloblasts responsible for dental enamel formation. Recently we reported that fluoride activates SIRT1 and autophagy as an adaptive response to protect cells from stress. However, it still remains unclear how SIRT1/autophagy is regulated in dental fluorosis. In this study, we demonstrate that fluoride exposure generates reactive oxygen species (ROS) and the resulting oxidative damage is counteracted by SIRT1/autophagy induction through c-Jun N-terminal kinase (JNK) signaling in ameloblasts. In the mouse-ameloblast-derived cell line LS8, fluoride induced ROS, mitochondrial damage including cytochrome-c release, up-regulation of UCP2, attenuation of ATP synthesis, and H2AX phosphorylation (γH2AX), which is a marker of DNA damage. We evaluated the effects of the ROS inhibitor N-acetylcysteine (NAC) and the JNK inhibitor SP600125 on fluoride-induced SIRT1/autophagy activation. NAC decreased fluoride-induced ROS generation and attenuated JNK and c-Jun phosphorylation. NAC decreased SIRT1 phosphorylation and formation of the autophagy marker LC3II, which resulted in an increase in the apoptosis mediators γH2AX and cleaved/activated caspase-3. SP600125 attenuated fluoride-induced SIRT1 phosphorylation, indicating that fluoride activates SIRT1/autophagy via the ROS-mediated JNK pathway. In enamel organs from rats or mice treated with 50, 100, or 125 ppm fluoride for 6 weeks, cytochrome-c release and the DNA damage markers 8-oxoguanine, p-ATM, and γH2AX were increased compared to those in controls (0 ppm fluoride). These results suggest that fluoride-induced ROS generation causes mitochondrial damage and DNA damage, which may lead to impairment of ameloblast function. To counteract this impairment, SIRT1/autophagy is induced via JNK signaling to protect cells/ameloblasts from fluoride-induced oxidative damage that may cause dental fluorosis. PMID:26431905

Markers of oxidative DNA damage in human interventions with fruit and berries.

PubMed

Freese, Riitta

2006-01-01

Diets rich in fruit and vegetables are associated with a decreased risk of several cancers via numerous possible mechanisms. For example, phytochemicals may decrease oxidative DNA damage and enhance DNA repair. Markers of oxidative DNA damage in human dietary intervention trials used most frequently include oxidized nucleosides such as 7-hydro-8-oxo-2'-deoxyguanosine, which can be analyzed from isolated DNA or urine. Single-cell gel electrophoresis has been widely used to measure baseline or H2O2-induced DNA strand breaks or sites of modified bases sensitive to repair enzymes recognizing oxidized purines or pyrimidines. Recently, markers of DNA repair also have been used. Few controlled human dietary interventions have investigated the specific effects of fruit or berries. There are indications that kiwifruit can decrease H2O2 sensitivity of lymphocyte DNA ex vivo and enhance DNA repair. Carefully controlled studies with flavonoid-rich fruit or berry juices found only few significant differences; less rigorously controlled studies gave more optimistic results. Data on the effects of fruit and berries on DNA damage in humans are scarce and inconclusive; adequately controlled studies with validated markers are needed. Because levels of DNA damage are usually low in young healthy volunteers, groups with an enhanced risk of DNA damage should be studied.

Expression of the Antioxidative Enzyme Peroxiredoxin 2 in Multiple Sclerosis Lesions in Relation to Inflammation

PubMed Central

Voigt, David; Scheidt, Uta; Derfuss, Tobias; Brück, Wolfgang; Junker, Andreas

2017-01-01

Multiple sclerosis is a chronic inflammatory disease of the central nervous system, characterized by demyelination and axonal damage as well as neuronal degeneration. Since oxygen-derived free radicals are an important factor leading to tissue damage in inflammatory multiple sclerosis (MS) lesions, research on antioxidative systems is essential to identify endogenous factors which can possibly counteract oxidative damage. As an important scavenging enzyme family, peroxiredoxins (PRDXs) play a crucial role in preventing oxidative damage; however little is known about their expression and function in MS lesions. In the present study we examined the expression of PRDX2 in white matter lesions of MS patients with long-standing, chronic disease. PRDX2 expression was investigated by immunohistochemistry in the context of oxidative stress and inflammation (determined by microglia/macrophage and T cell infiltration) in ten MS autopsy cases as well as seven control autopsy cases. PRDX2 was found to be upregulated in white matter MS lesions mainly in astrocytes, and its expression level was positively correlated with the degree of inflammation and oxidative stress. Our data suggest that PRDX2 expression contributes to the resistance of astrocytes against oxidative damage. PMID:28375164

Mitigation in Multiple Effects of Graphene Oxide Toxicity in Zebrafish Embryogenesis Driven by Humic Acid.

PubMed

Chen, Yuming; Ren, Chaoxiu; Ouyang, Shaohu; Hu, Xiangang; Zhou, Qixing

2015-08-18

Graphene oxide (GO) is a widely used carbonaceous nanomaterial. To date, the influence of natural organic matter (NOM) on GO toxicity in aquatic vertebrates has not been reported. During zebrafish embryogenesis, GO induced a significant hatching delay and cardiac edema. The intensive interactions of GO with the chorion induces damage to chorion protuberances, excessive generation of (•)OH, and changes in protein secondary structure. In contrast, humic acid (HA), a ubiquitous form of NOM, significantly relieved the above adverse effects. HA reduced the interactions between GO and the chorion and mitigated chorion damage by regulating the morphology, structures, and surface negative charges of GO. HA also altered the uptake and deposition of GO and decreased the aggregation of GO in embryonic yolk cells and deep layer cells. Furthermore, HA mitigated the mitochondrial damage and oxidative stress induced by GO. This work reveals a feasible antidotal mechanism for GO in the presence of NOM and avoids overestimating the risks of GO in the natural environment.

The antileishmanial drug miltefosine (Impavido(®)) causes oxidation of DNA bases, apoptosis, and necrosis in mammalian cells.

PubMed

Castelo Branco, Patrícia Valéria; Soares, Rossy-Eric Pereira; de Jesus, Luís Cláudio Lima; Moreira, Vanessa Ribeiro; Alves, Hugo José; de Castro Belfort, Marta Regina; Silva, Vera Lucia Maciel; Ferreira Pereira, Silma Regina

2016-08-01

Miltefosine was developed to treat skin cancer; further studies showed that the drug also has activity against Leishmania. Miltefosine is the first oral agent for treating leishmaniasis. However, its mechanism of action is not completely understood. We have evaluated the induction of DNA damage by miltefosine. Cytotoxicity and genotoxicity (comet assay) tests were performed on human leukocytes exposed to the drug in vitro. Apoptosis and necrosis were also evaluated. In vivo tests were conducted in Swiss male mice (Mus musculus) treated orally with miltefosine. Oxidation of DNA bases in peripheral blood cells was measured using the comet assay followed by digestion with formamidopyrimidine glycosylase (FPG), which removes oxidized guanine bases. The micronucleus test was performed on bone marrow erythrocytes. Miltefosine caused DNA damage, apoptosis, and necrosis in vitro. Mice treated with miltefosine showed an increase in the DNA damage score, which was further increased following FPG digestion. The micronucleus test was also positive. Copyright © 2016 Elsevier B.V. All rights reserved.

Lysergic acid diethylamide causes photoreceptor cell damage through inducing inflammatory response and oxidative stress.

PubMed

Hu, Qi-Di; Xu, Ling-Li; Gong, Yan; Wu, Guo-Hai; Wang, Yu-Wen; Wu, Shan-Jun; Zhang, Zhe; Mao, Wei; Zhou, Yu-Sheng; Li, Qin-Bo; Yuan, Jian-Shu

2018-01-19

Lysergic acid diethylamide (LSD), a classical hallucinogen, was used as a popular and notorious substance of abuse in various parts of the world. Its abuse could result in long-lasting abnormalities in retina and little is known about the exact mechanism. This study was to investigate the effect of LSD on macrophage activation state at non-toxic concentration and its resultant toxicity to photoreceptor cells. Results showed that cytotoxicity was caused by LSD on 661 W cells after co-culturing with RAW264.7 cells. Treatment with LSD-induced RAW264.7 cells to the M1 phenotype, releasing more pro-inflammatory cytokines, and increasing the M1-related gene expression. Moreover, after co-culturing with RAW264.7 cells, significant oxidative stress in 661 W cells treated with LSD was observed, by increasing the level of malondialdehyde (MDA) and reactive oxygen species (ROS), and decreasing the level of glutathione (GSH) and the activity of superoxide dismutase (SOD). Our study demonstrated that LSD caused photoreceptor cell damage by inducing inflammatory response and resultant oxidative stress, providing the scientific rationale for the toxicity of LSD to retina.

Effects of Aging and Oxidative Stress on Spermatozoa of Superoxide-Dismutase 1- and Catalase-Null Mice1

PubMed Central

Selvaratnam, Johanna S.; Robaire, Bernard

2016-01-01

Advanced paternal age is linked to complications in pregnancy and genetic diseases in offspring. Aging results in excess reactive oxygen species (ROS) and DNA damage in spermatozoa; this damage can be transmitted to progeny with detrimental consequences. Although there is a loss of antioxidants with aging, the impact on aging male germ cells of the complete absence of either catalase (CAT) or superoxide dismutase 1 (SOD1) has not been investigated. We used CAT-null (Cat−/−) and SOD1-null (Sod−/−) mice to determine whether loss of these antioxidants increases germ cell susceptibility to redox dysfunction with aging. Aging reduced fertility and the numbers of Sertoli and germ cells in all mice. Aged Sod−/− mice displayed an increased loss of fertility compared to aged wild-type mice. Treatment with the pro-oxidant SIN-10 increased ROS in spermatocytes of aged wild-type and Sod−/− mice, while aged Cat−/− mice were able to neutralize this ROS. The antioxidant peroxiredoxin 1 (PRDX1) increased with age in wild-type and Cat−/− mice but was consistently low in young and aged Sod−/− mice. DNA damage and repair markers (γ-H2AX and 53BP1) were reduced with aging and lower in young Sod−/− and Cat−/− mice. Colocalization of γ-H2AX and 53BP1 suggested active repair in young wild-type mice but reduced in young Cat−/− and in Sod−/− mice and with age. Oxidative DNA damage (8-oxodG) increased in young Sod−/− mice and with age in all mice. These studies show that aged Sod−/− mice display severe redox dysfunction, while wild-type and Cat−/− mice have compensatory mechanisms to partially alleviate oxidative stress and reduce age-related DNA damage in spermatozoa. Thus, SOD1 but not CAT is critical to the maintenance of germ cell quality with aging. PMID:27465136

Effects of Aging and Oxidative Stress on Spermatozoa of Superoxide-Dismutase 1- and Catalase-Null Mice.

PubMed

Selvaratnam, Johanna S; Robaire, Bernard

2016-09-01

Advanced paternal age is linked to complications in pregnancy and genetic diseases in offspring. Aging results in excess reactive oxygen species (ROS) and DNA damage in spermatozoa; this damage can be transmitted to progeny with detrimental consequences. Although there is a loss of antioxidants with aging, the impact on aging male germ cells of the complete absence of either catalase (CAT) or superoxide dismutase 1 (SOD1) has not been investigated. We used CAT-null (Cat(-/-)) and SOD1-null (Sod(-/-)) mice to determine whether loss of these antioxidants increases germ cell susceptibility to redox dysfunction with aging. Aging reduced fertility and the numbers of Sertoli and germ cells in all mice. Aged Sod(-/-) mice displayed an increased loss of fertility compared to aged wild-type mice. Treatment with the pro-oxidant SIN-10 increased ROS in spermatocytes of aged wild-type and Sod(-/-) mice, while aged Cat(-/-) mice were able to neutralize this ROS. The antioxidant peroxiredoxin 1 (PRDX1) increased with age in wild-type and Cat(-/-) mice but was consistently low in young and aged Sod(-/-) mice. DNA damage and repair markers (γ-H2AX and 53BP1) were reduced with aging and lower in young Sod(-/-) and Cat(-/-) mice. Colocalization of γ-H2AX and 53BP1 suggested active repair in young wild-type mice but reduced in young Cat(-/-) and in Sod(-/-) mice and with age. Oxidative DNA damage (8-oxodG) increased in young Sod(-/-) mice and with age in all mice. These studies show that aged Sod(-/-) mice display severe redox dysfunction, while wild-type and Cat(-/-) mice have compensatory mechanisms to partially alleviate oxidative stress and reduce age-related DNA damage in spermatozoa. Thus, SOD1 but not CAT is critical to the maintenance of germ cell quality with aging. © 2016 by the Society for the Study of Reproduction, Inc.

Mitochondria regulate DNA damage and genomic instability induced by high LET radiation

NASA Astrophysics Data System (ADS)

Zhang, Bo; Davidson, Mercy M.; Hei, Tom K.

2014-04-01

High linear energy transfer (LET) radiation including α particles and heavy ions is the major type of radiation found in space and is considered a potential health risk for astronauts. Even though the chance that these high LET particles traversing through the cytoplasm of cells is higher than that through the nuclei, the contribution of targeted cytoplasmic irradiation to the induction of genomic instability and other chromosomal damages induced by high LET radiation is not known. In the present study, we investigated whether mitochondria are the potential cytoplasmic target of high LET radiation in mediating cellular damage using a mitochondrial DNA (mtDNA) depleted (ρ0) human small airway epithelial (SAE) cell model and a precision charged particle microbeam with a beam width of merely one micron. Targeted cytoplasmic irradiation by high LET α particles induced DNA oxidative damage and double strand breaks in wild type ρ+ SAE cells. Furthermore, there was a significant increase in autophagy and micronuclei, which is an indication of genomic instability, together with the activation of nuclear factor kappa-B (NF-κB) and mitochondrial inducible nitric oxide synthase (iNOS) signaling pathways in ρ+ SAE cells. In contrast, ρ0 SAE cells exhibited a significantly lower response to these same endpoints examined after cytoplasmic irradiation with high LET α particles. The results indicate that mitochondria are essential in mediating cytoplasmic radiation induced genotoxic damage in mammalian cells. Furthermore, the findings may shed some light in the design of countermeasures for space radiation.

Mitoprotective antioxidant EUK-134 stimulates fatty acid oxidation and prevents hypertrophy in H9C2 cells.

PubMed

Purushothaman, Sreeja; Nair, R Renuka

2016-09-01

Oxidative stress is an important contributory factor for the development of cardiovascular diseases like hypertension-induced hypertrophy. Mitochondrion is the major source of reactive oxygen species. Hence, protecting mitochondria from oxidative damage can be an effective therapeutic strategy for the prevention of hypertensive heart disease. Conventional antioxidants are not likely to be cardioprotective, as they cannot protect mitochondria from oxidative damage. EUK-134 is a salen-manganese complex with superoxide dismutase and catalase activity. The possible role of EUK-134, a mitoprotective antioxidant, in the prevention of hypertrophy of H9C2 cells was examined. The cells were stimulated with phenylephrine (50 μM), and hypertrophy was assessed based on cell volume and expression of brain natriuretic peptide and calcineurin. Enhanced myocardial lipid peroxidation and protein carbonyl content, accompanied by nuclear factor-kappa B gene expression, confirmed the presence of oxidative stress in hypertrophic cells. Metabolic shift was evident from reduction in the expression of medium-chain acyl-CoA dehydrogenase. Mitochondrial oxidative stress was confirmed by the reduced expression of mitochondria-specific antioxidant peroxiredoxin-3 and enhanced mitochondrial superoxide production. Compromised mitochondrial function was apparent from reduced mitochondrial membrane potential. Pretreatment with EUK-134 (10 μM) was effective in the prevention of hypertrophic changes in H9C2 cells, reduction of oxidative stress, and prevention of metabolic shift. EUK-134 treatment improved the oxidative status of mitochondria and reversed hypertrophy-induced reduction of mitochondrial membrane potential. Supplementation with EUK-134 is therefore identified as a novel approach to attenuate cardiac hypertrophy and lends scope for the development of EUK-134 as a therapeutic agent in the management of human cardiovascular disease.

Ascorbate attenuates pulmonary emphysema by inhibiting tobacco smoke and Rtp801-triggered lung protein modification and proteolysis.

PubMed

Gupta, Indranil; Ganguly, Souradipta; Rozanas, Christine R; Stuehr, Dennis J; Panda, Koustubh

2016-07-19

Cigarette smoking causes emphysema, a fatal disease involving extensive structural and functional damage of the lung. Using a guinea pig model and human lung cells, we show that oxidant(s) present in tobacco smoke not only cause direct oxidative damage of lung proteins, contributing to the major share of lung injury, but also activate Rtp801, a key proinflammatory cellular factor involved in tobacco smoke-induced lung damage. Rtp801 triggers nuclear factor κB and consequent inducible NOS (iNOS)-mediated overproduction of NO, which in combination with excess superoxide produced during Rtp801 activation, contribute to increased oxido-nitrosative stress and lung protein nitration. However, lung-specific inhibition of iNOS with a iNOS-specific inhibitor, N6-(1-iminoethyl)-L-lysine, dihydrochloride (L-NIL) solely restricts lung protein nitration but fails to prevent or reverse the major tobacco smoke-induced oxidative lung injury. In comparison, the dietary antioxidant, ascorbate or vitamin C, can substantially prevent such damage by inhibiting both tobacco smoke-induced lung protein oxidation as well as activation of pulmonary Rtp801 and consequent iNOS/NO-induced nitration of lung proteins, that otherwise lead to increased proteolysis of such oxidized or nitrated proteins by endogenous lung proteases, resulting in emphysematous lung damage. Vitamin C also restricts the up-regulation of matrix-metalloproteinase-9, the major lung protease involved in the proteolysis of such modified lung proteins during tobacco smoke-induced emphysema. Overall, our findings implicate tobacco-smoke oxidant(s) as the primary etiopathogenic factor behind both the noncellular and cellular damage mechanisms governing emphysematous lung injury and demonstrate the potential of vitamin C to accomplish holistic prevention of such damage.

Ascorbate attenuates pulmonary emphysema by inhibiting tobacco smoke and Rtp801-triggered lung protein modification and proteolysis

PubMed Central

Gupta, Indranil; Ganguly, Souradipta; Rozanas, Christine R.; Stuehr, Dennis J.

2016-01-01

Cigarette smoking causes emphysema, a fatal disease involving extensive structural and functional damage of the lung. Using a guinea pig model and human lung cells, we show that oxidant(s) present in tobacco smoke not only cause direct oxidative damage of lung proteins, contributing to the major share of lung injury, but also activate Rtp801, a key proinflammatory cellular factor involved in tobacco smoke-induced lung damage. Rtp801 triggers nuclear factor κB and consequent inducible NOS (iNOS)-mediated overproduction of NO, which in combination with excess superoxide produced during Rtp801 activation, contribute to increased oxido-nitrosative stress and lung protein nitration. However, lung-specific inhibition of iNOS with a iNOS-specific inhibitor, N6-(1-iminoethyl)-L-lysine, dihydrochloride (L-NIL) solely restricts lung protein nitration but fails to prevent or reverse the major tobacco smoke-induced oxidative lung injury. In comparison, the dietary antioxidant, ascorbate or vitamin C, can substantially prevent such damage by inhibiting both tobacco smoke-induced lung protein oxidation as well as activation of pulmonary Rtp801 and consequent iNOS/NO-induced nitration of lung proteins, that otherwise lead to increased proteolysis of such oxidized or nitrated proteins by endogenous lung proteases, resulting in emphysematous lung damage. Vitamin C also restricts the up-regulation of matrix-metalloproteinase-9, the major lung protease involved in the proteolysis of such modified lung proteins during tobacco smoke-induced emphysema. Overall, our findings implicate tobacco-smoke oxidant(s) as the primary etiopathogenic factor behind both the noncellular and cellular damage mechanisms governing emphysematous lung injury and demonstrate the potential of vitamin C to accomplish holistic prevention of such damage. PMID:27382160

[Definition of parameters of the condition of oxidizing stress in smooth muscle cells under influence of exogenous nitroso-glutatyon in vitro].

PubMed

Kapilevich, L V; Nosarev, A V; D'iakova, E Iu; Andrushkevich, V V; Nasedkina, A K; Nosareva, O L; Davlet'iarova, K V; Ogorodova, L M; Kovalev, I V; Baskakov, M B; Medvedev, M A

2007-08-01

Influence of exogenous nitroso-glutatyon on intensity of oxidizing processes in smooth muscles of colon and bronchial tubes in intact and atopic sensitised porpoises (guinea pigs) was studied. In sensitised porpoises, antioxidant protection has been initially reduced against the background of increased maintenance of products of oxidizing that reflects a picture of oxidizing damage and can be associated with an inflammatory process. In incubation with nitroso-glutatyon, a decrease in activities of syperoxiddismutase and catalase is marked and, in sensitised animals, this effect has been expressed to a lesser degree. Syperoxiddismutase and catalase are antioxidant for the enzymes participating in protection of cells from free-radical damage. A dose-dependence decrease in activity catalase and syperoxiddismutase is defined by a parity of the enzymes participating in disintegration of nitrosoglutatyon and the enzymes which have kept antioxidant activity.

Genotoxic effects of camphorquinone and DMT on human oral and intestinal cells.

PubMed

Wessels, Miriam; Rimkus, Julia; Leyhausen, Gabriele; Volk, Joachim; Geurtsen, Werner

2015-10-01

Released components of oral biomaterials can leach into the oral cavity and may subsequently reach the gastrointestinal tract. Camphorquinone (CQ) is the most common used photoinitiator in resinous restorative materials and is often combined with the co-initiator N,N-dimethyl-p-toluidine (DMT). It has been shown that CQ exerts cytotoxic effects, at least partially due to the generation of reactive oxygen species (ROS). Objective of this study was to examine the cytotoxic and genotoxic potential of CQ in human oral keratinocytes (OKF6/TERT2) and immortalized epithelial colorectal adenocarcinoma cells (Caco-2). Furthermore, the effects of visible-light irradiation and the co-initiator DMT were investigated as well as the generation of ROS, the potential protective effect of glutathione (GSH) and a recovery period of CQ-treated Caco-2 cells. The alkaline comet assay was used to determine DNA damage. Additionally, an enzyme modified comet assay was applied, which detects 7,8-dihydro-8-oxoguanine (8-oxoguanine), a reliable marker for oxidative stress. Our data revealed that high concentrations of CQ induced DNA lesions in OKF6/TERT2 cells. This DNA damage is at least partly caused by the generation of 8-oxoguanine. In addition, CQ and DMT increased ROS formation and induced DNA damage in Caco-2 cells. CQ-treatment resulted in generation of 8-oxoguanine. The antioxidant GSH efficiently prevented CQ-associated DNA damage. Furthermore, a recovery following CQ-treatment significantly reduced DNA damage. We conclude that CQ-induced DNA damage is caused by oxidative stress in oral and intestinal cells. These lesions can be prevented and possibly repaired by GSH-treatment and recovery of cells after the photoinitiator is removed from cultures. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

The Neuroprotective Effects of Brazilian Green Propolis on Neurodegenerative Damage in Human Neuronal SH-SY5Y Cells

PubMed Central

Ni, Junjun; Meng, Jie; Zhu, Aiqin; Zhong, Xin; Wu, Shizheng; Nakanishi, Hiroshi

2017-01-01

Oxidative stress and synapse dysfunction are the major neurodegenerative damage correlated to cognitive impairment in Alzheimer's disease (AD). We have found that Brazilian green propolis (propolis) improves the cognitive functions of mild cognitive impairment patients living at high altitude; however, mechanism underlying the effects of propolis is unknown. In the present study, we investigated the effects of propolis on oxidative stress, expression of brain-derived neurotrophic factor (BDNF), and activity-regulated cytoskeleton-associated protein (Arc), the critical factors of synapse efficacy, using human neuroblastoma SH-SY5Y cells. Pretreatment with propolis significantly ameliorated the hydrogen peroxide- (H2O2-) induced cytotoxicity in SH-SY5Y cells. Furthermore, propolis significantly reduced the H2O2-generated reactive oxygen species (ROS) derived from mitochondria and 8-oxo-2′-deoxyguanosine (8-oxo-dG, the DNA oxidative damage marker) but significantly reversed the fibrillar β-amyloid and IL-1β-impaired BDNF-induced Arc expression in SH-SY5Y cells. Furthermore, propolis significantly upregulated BDNF mRNA expression in time- and dose-dependent manners. In addition, propolis induced Arc mRNA and protein expression via phosphoinositide-3 kinase (PI3K). These observations strongly suggest that propolis protects from the neurodegenerative damage in neurons through the properties of various antioxidants. The present study provides a potential molecular mechanism of Brazilian green propolis in prevention of cognitive impairment in AD as well as aging. PMID:28265338

The Neuroprotective Effects of Brazilian Green Propolis on Neurodegenerative Damage in Human Neuronal SH-SY5Y Cells.

PubMed

Ni, Junjun; Wu, Zhou; Meng, Jie; Zhu, Aiqin; Zhong, Xin; Wu, Shizheng; Nakanishi, Hiroshi

2017-01-01

Oxidative stress and synapse dysfunction are the major neurodegenerative damage correlated to cognitive impairment in Alzheimer's disease (AD). We have found that Brazilian green propolis (propolis) improves the cognitive functions of mild cognitive impairment patients living at high altitude; however, mechanism underlying the effects of propolis is unknown. In the present study, we investigated the effects of propolis on oxidative stress, expression of brain-derived neurotrophic factor (BDNF), and activity-regulated cytoskeleton-associated protein (Arc), the critical factors of synapse efficacy, using human neuroblastoma SH-SY5Y cells. Pretreatment with propolis significantly ameliorated the hydrogen peroxide- (H 2 O 2 -) induced cytotoxicity in SH-SY5Y cells. Furthermore, propolis significantly reduced the H 2 O 2 -generated reactive oxygen species (ROS) derived from mitochondria and 8-oxo-2'-deoxyguanosine (8-oxo-dG, the DNA oxidative damage marker) but significantly reversed the fibrillar β -amyloid and IL-1 β -impaired BDNF-induced Arc expression in SH-SY5Y cells. Furthermore, propolis significantly upregulated BDNF mRNA expression in time- and dose-dependent manners. In addition, propolis induced Arc mRNA and protein expression via phosphoinositide-3 kinase (PI3K). These observations strongly suggest that propolis protects from the neurodegenerative damage in neurons through the properties of various antioxidants. The present study provides a potential molecular mechanism of Brazilian green propolis in prevention of cognitive impairment in AD as well as aging.

Nrf2 protects photoreceptor cells from photo-oxidative stress induced by blue light.

PubMed

Chen, Wan-Ju; Wu, Caiying; Xu, Zhenhua; Kuse, Yoshiki; Hara, Hideaki; Duh, Elia J

2017-01-01

Oxidative stress plays a key role in age-related macular degeneration and hereditary retinal degenerations. Light damage in rodents has been used extensively to model oxidative stress-induced photoreceptor degeneration, and photo-oxidative injury from blue light is particularly damaging to photoreceptors. The endogenous factors protecting photoreceptors from oxidative stress, including photo-oxidative stress, are continuing to be elucidated. In this study, we evaluated the effect of blue light exposure on photoreceptors and its relationship to Nrf2 using cultured murine photoreceptor (661W) cells. 661W cells were exposed to blue light at 2500 lux. Exposure to blue light for 6-24 h resulted in a significant increase in intracellular reactive oxygen species (ROS) and death of 661W cells in a time-dependent fashion. Blue light exposure resulted in activation of Nrf2, as indicated by an increase in nuclear translocation of Nrf2. This was associated with a significant induction of expression of Nrf2 as well as an array of Nrf2 target genes, including antioxidant genes, as indicated by quantitative reverse transcription PCR (qRT-PCR). In order to determine the functional role of Nrf2, siRNA-mediated knockdown studies were performed. Nrf2-knockdown in 661W cells resulted in significant exacerbation of blue light-induced reactive oxygen species levels as well as cell death. Taken together, these findings indicate that Nrf2 is an important endogenous protective factor against oxidative stress in photoreceptor cells. This suggests that drugs targeting Nrf2 could be considered as a neuroprotective strategy for photoreceptors in AMD and other retinal conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

The role of the RB tumour suppressor pathway in oxidative stress responses in the haematopoietic system

PubMed Central

Macleod, Kay F.

2010-01-01

Exposure to pro-oxidants and defects in the repair of oxidative base damage are associated with disease and ageing and also contribute to the development of anaemia, bone marrow failure and haematopoietic malignancies. This Review assesses emerging data indicative of a specific role for the RB tumour suppressor pathway in the response of the haematopoietic system to oxidative stress. This is mediated through signalling pathways that involve DNA damage sensors, forkhead box O (Foxo) transcription factors and p38 mitogen-activated protein kinases and has downstream consequences for cell cycle progression, antioxidant capacity, mitochondrial mass and cellular metabolism. PMID:18800074

Necrosis is increased in lymphoblastoid cell lines from children with autism compared with their non-autistic siblings under conditions of oxidative and nitrosative stress.

PubMed

Main, Penelope A E; Thomas, Philip; Esterman, Adrian; Fenech, Michael F

2013-07-01

Autism spectrum disorders are a heterogeneous group of neurodevelopmental conditions characterised by impairments in reciprocal social interaction, communication and stereotyped behaviours. As increased DNA damage events have been observed in a range of other neurological disorders, it was hypothesised that they would be elevated in lymphoblastoid cell lines (LCLs) obtained from children with autism compared with their non-autistic siblings. Six case-sibling pairs of LCLs from children with autistic disorder and their non-autistic siblings were obtained from the Autism Genetic Resource Exchange (AGRE) and cultured in standard RPMI-1640 tissue culture medium. Cells were exposed to medium containing either 0, 25, 50, 100 and 200 µM hydrogen peroxide (an oxidative stressor) or 0, 5, 10, 20 and 40 µM s-nitroprusside (a nitric oxide producer) for 1h. Following exposure, the cells were microscopically scored for DNA damage, cytostasis and cytotoxicity biomarkers as measured using the cytokinesis-block micronucleus cytome assay. Necrosis was significantly increased in cases relative to controls when exposed to oxidative and nitrosative stress (P = 0.001 and 0.01, respectively). Nuclear division index was significantly lower in LCLs from children with autistic disorder than their non-autistic siblings when exposed to hydrogen peroxide (P = 0.016), but there was no difference in apoptosis, micronucleus frequency, nucleoplasmic bridges or nuclear buds. Exposure to s-nitroprusside significantly increased the number of micronuclei in non-autistic siblings compared with cases (P = 0.003); however, other DNA damage biomarkers, apoptosis and nuclear division did not differ significantly between groups. The findings of this study show (i) that LCLs from children with autism are more sensitive to necrosis under conditions of oxidative and nitrosative stress than their non-autistic siblings and (ii) refutes the hypothesis that children with autistic disorder are abnormally susceptible to DNA damage.

Necrosis is increased in lymphoblastoid cell lines from children with autism compared with their non-autistic siblings under conditions of oxidative and nitrosative stress

PubMed Central

Fenech, Michael F.

2013-01-01

Autism spectrum disorders are a heterogeneous group of neurodevelopmental conditions characterised by impairments in reciprocal social interaction, communication and stereotyped behaviours. As increased DNA damage events have been observed in a range of other neurological disorders, it was hypothesised that they would be elevated in lymphoblastoid cell lines (LCLs) obtained from children with autism compared with their non-autistic siblings. Six case–sibling pairs of LCLs from children with autistic disorder and their non-autistic siblings were obtained from the Autism Genetic Resource Exchange (AGRE) and cultured in standard RPMI-1640 tissue culture medium. Cells were exposed to medium containing either 0, 25, 50, 100 and 200 µM hydrogen peroxide (an oxidative stressor) or 0, 5, 10, 20 and 40 µM s-nitroprusside (a nitric oxide producer) for 1h. Following exposure, the cells were microscopically scored for DNA damage, cytostasis and cytotoxicity biomarkers as measured using the cytokinesis-block micronucleus cytome assay. Necrosis was significantly increased in cases relative to controls when exposed to oxidative and nitrosative stress (P = 0.001 and 0.01, respectively). Nuclear division index was significantly lower in LCLs from children with autistic disorder than their non-autistic siblings when exposed to hydrogen peroxide (P = 0.016), but there was no difference in apoptosis, micronucleus frequency, nucleoplasmic bridges or nuclear buds. Exposure to s-nitroprusside significantly increased the number of micronuclei in non-autistic siblings compared with cases (P = 0.003); however, other DNA damage biomarkers, apoptosis and nuclear division did not differ significantly between groups. The findings of this study show (i) that LCLs from children with autism are more sensitive to necrosis under conditions of oxidative and nitrosative stress than their non-autistic siblings and (ii) refutes the hypothesis that children with autistic disorder are abnormally susceptible to DNA damage. PMID:23766106

CYP2E1 induction leads to oxidative stress and cytotoxicity in glutathione-depleted cerebellar granule neurons.

PubMed

Valencia-Olvera, Ana Carolina; Morán, Julio; Camacho-Carranza, Rafael; Prospéro-García, Oscar; Espinosa-Aguirre, Jesús Javier

2014-10-01

Increasing evidence suggests that brain cytochrome P450 (CYP) can contribute to the in situ metabolism of xenobiotics. In the liver, some xenobiotics can be metabolized by CYPs into more reactive products that can damage hepatocytes and induce cell death. In addition, normal CYP activity may produce reactive oxygen species (ROS) that contribute to cell damage through oxidative mechanisms. CYP2E1 is a CYP isoform that can generate ROS leading to cytotoxicity in multiple tissue types. The aim of this study was to determine whether CYP2E1 induction may lead to significant brain cell impairment. Immunological analysis revealed that exposure of primary cerebellar granule neuronal cultures to the CYP inducer isoniazid, increased CYP2E1 expression. In the presence of buthionine sulfoximine, an agent that reduces glutathione levels, isoniazid treatment also resulted in reactive oxygen species (ROS) production, DNA oxidation and cell death. These effects were attenuated by simultaneous exposure to diallyl sulfide, a CYP2E1 inhibitor, or to a mimetic of superoxide dismutase/catalase, (Euka). These results suggest that in cases of reduced antioxidant levels, the induction of brain CYP2E1 could represent a risk of in situ neuronal damage. Copyright © 2014 Elsevier Ltd. All rights reserved.

Amelioration of streptozotocin‑induced pancreatic β cell damage by morin: Involvement of the AMPK‑FOXO3‑catalase signaling pathway.

PubMed

Wang, Ning; Zhang, Jiahui; Qin, Mengting; Yi, Wenjing; Yu, Shuang; Chen, Yi; Guan, Jing; Zhang, Rui

2018-03-01

Pancreatic β cells are sensitive to oxidative stress, which is one of the predominant causes of cell damage and the emergence of diabetes. The identification of effective therapeutic strategies to protect pancreatic cells from oxidative stress has increased interest in the screening of antioxidants from natural products. The present study aimed to investigate the protective effects of morin against streptozotocin (STZ)‑induced cell damage in a rat insulinoma cell line (RINm5F pancreatic β cells) and to identify the underlying mechanisms. The results indicated that morin inhibited the increase in intracellular reactive oxygen species, attenuated the activity of poly (ADP‑ribose) polymerase, restored intracellular nicotinamide adenine dinucleotide levels and reduced the apoptotic cell death of STZ‑treated pancreatic β cells. Treatment with morin significantly upregulated catalase in pancreatic β cells, and ameliorated the STZ‑induced loss of catalase at the genetic, protein and enzymatic level. In further experiments, morin induced the phosphorylation of 5' adenosine monophosphate‑activated protein kinase (AMPK), which subsequently promoted the translocation of forkhead box O3 (FOXO3) to the nucleus. Specific small interfering RNAs (siRNAs) against AMPK and FOXO3 suppressed morin‑induced catalase expression. Furthermore, catalase‑specific siRNA abolished the protective effects of morin against STZ‑stimulated cell death. Taken together, these results indicated that morin protected RINm5F cells from STZ‑induced cell damage by triggering the phosphorylation of AMPK, thus resulting in subsequent activation of FOXO3 and induction of catalase.

Wheat peptides reduce oxidative stress and inhibit NO production through modulating μ-opioid receptor in a rat NSAID-induced stomach damage model.

PubMed

Yin, Hong; Cai, Hui-Zhen; Wang, Shao-Kang; Yang, Li-Gang; Sun, Gui-Ju

2015-01-01

Non-steroidal anti-inflammatory drugs (NSAIDs) induce tissue damage and oxidative stress in animal models of stomach damage. In the present study, the protective effects of wheat peptides were evaluated in a NSAID-induced stomach damage model in rats. Different doses of wheat peptides or distilled water were administered daily by gavage for 30 days before the rat stomach damage model was established by administration of NSAIDs (aspirin and indomethacin) into the digestive tract twice. The treatment of wheat peptides decreased the NSAID-induced gastric epithelial cell degeneration and oxidative stress and NO levels in the rats. Wheat peptides significantly increased the superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and decreased iNOS activity in stomach. The mRNA expression level of μ-opioid receptor was significantly decreased in wheat peptides-treated rats than that in in the control rats. The results suggest that NSAID drugs induced stomach damage in rats, wchih can be prevented by wheat peptides. The mechanisms for the protective effects were most likely through reducing NSAID-induced oxidative stress. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Redox-Sensitive Cerium Oxide Nanoparticles Protect Human Keratinocytes from Oxidative Stress Induced by Glutathione Depletion.

PubMed

Singh, Ragini; Karakoti, Ajay S; Self, William; Seal, Sudipta; Singh, Sanjay

2016-11-22

Cerium oxide nanoparticles (CeNPs) have gathered much attention in the biomedical field due to its unique antioxidant property. It can protect cells and tissues from oxidative stress induced damage due to its autoregenerative redox cycle. Our study explores the antioxidant and antigenotoxic behavior of PEGylated CeNPs toward oxidative insult produced by buthionine sulfoximine (BSO) in human keratinocytes (HaCaT cells). BSO inhibits the γ-glutamylcysteinesynthetase (γ-GCS) enzyme and thus acts as a glutathione (GSH) depleting agent to modulate the cellular redox potential. GSH is a natural ROS scavenger present in the mammalian cells, and its depletion causes generation of reactive oxygen species (ROS). In this study, we challenged HaCaT cells (keratinocytes) with BSO to alter the redox potential within the cell and monitored toxicity, ROS generation, and nuclear fragmentation. We also followed changes in expressions of related proteins and genes. We found that PEGylated CeNPs can protect HaCaT cells from BSO-induced oxidative damage. BSO-exposed cells, preincubated with PEGylated CeNPs, showed better cell survival and significant decrease in the intracellular levels of ROS. We also observed decrease in lactate dehydrogenase (LDH) release and nuclear fragmentation in CeNP-treated cells that were challenged with BSO as compared to treatment with BSO alone. Exposure of HaCaT cells with BSO leads to altered expression of antioxidant genes and proteins, i.e., thioredoxin reductase (TrxR) and peroxiredoxin 6 (Prx6) whereas, in our study, pretreatment of PEGylated CeNPs reduces the need for induction of genes that produce enzymes involved in the defense against oxidative stress. Since, growing evidence argued the involvement of ROS in mediating death of mammalian cells in several ailments, our finding reinforces the use of PEGylated CeNPs as a potent pharmacological agent under the lower cellular GSH/GSSG ratios for the treatment of diseases mediated by free radicals.

Cell Injury and Repair Resulting from Sleep Loss and Sleep Recovery in Laboratory Rats

PubMed Central

Everson, Carol A.; Henchen, Christopher J.; Szabo, Aniko; Hogg, Neil

2014-01-01

Study Objectives: Increased cell injury would provide the type of change in constitution that would underlie sleep disruption as a risk factor for multiple diseases. The current study was undertaken to investigate cell injury and altered cell fate as consequences of sleep deprivation, which were predicted from systemic clues. Design: Partial (35% sleep reduction) and total sleep deprivation were produced in rats for 10 days, which was tolerated and without overtly deteriorated health. Recovery rats were similarly sleep deprived for 10 days, then allowed undisturbed sleep for 2 days. The plasma, liver, lung, intestine, heart, and spleen were analyzed and compared to control values for damage to DNA, proteins, and lipids; apoptotic cell signaling and death; cell proliferation; and concentrations of glutathione peroxidase and catalase. Measurements and Results: Oxidative DNA damage in totally sleep deprived rats was 139% of control values, with organ-specific effects in the liver (247%), lung (166%), and small intestine (145%). Overall and organ-specific DNA damage was also increased in partially sleep deprived rats. In the intestinal epithelium, total sleep deprivation resulted in 5.3-fold increases in dying cells and 1.5-fold increases in proliferating cells, compared with control. Two days of recovery sleep restored the balance between DNA damage and repair, and resulted in normal or below-normal metabolic burdens and oxidative damage. Conclusions: These findings provide physical evidence that sleep loss causes cell damage, and in a manner expected to predispose to replication errors and metabolic abnormalities; thereby providing linkage between sleep loss and disease risk observed in epidemiological findings. Properties of recovery sleep include biochemical and molecular events that restore balance and decrease cell injury. Citation: Everson CA, Henchen CJ, Szabo A, Hogg N. Cell injury and repair resulting from sleep loss and sleep recovery in laboratory rats. SLEEP 2014;37(12):1929-1940. PMID:25325492

Role of interferon regulatory factor-1 in lipopolysaccharide-induced mitochondrial damage and oxidative stress responses in macrophages

PubMed Central

Deng, Song-Yun; Zhang, Le-Meng; Ai, Yu-hang; Pan, Pin-Hua; Zhao, Shuang-Ping; Su, Xiao-Li; Wu, Dong-Dong; Tan, Hong-Yi; Zhang, Li-Na; Tsung, Allan

2017-01-01

Sepsis causes many early deaths; both macrophage mitochondrial damage and oxidative stress responses are key factors in its pathogenesis. Although the exact mechanisms responsible for sepsis-induced mitochondrial damage are unknown, the nuclear transcription factor, interferon regulatory factor-1 (IRF-1) has been reported to cause mitochondrial damage in several diseases. Previously, we reported that in addition to promoting systemic inflammation, IRF-1 promoted the apoptosis of and inhibited autophagy in macrophages. In the present study, we hypothesized that lipopolysaccharide (LPS)-induced IRF-1 activation in macrophages may promote mitochondrial damage and oxidative stress. In vitro, LPS was found to promote IRF-1 activation, reactive oxygen species (ROS) production, adenosine triphosphate (ATP) depletion, superoxide dismutase (SOD) consumption, malondialdehyde (MDA) accumulation and mitochondrial depolarization in macrophages in a time- and dose-dependent manner. These effects were abrogated in cells in which IRF-1 was knocked down. Furthermore, IRF-1 overexpression increased LPS-induced oxidative stress responses and mitochondrial damage. In vivo, peritoneal macrophages obtained from IRF-1 knockout (KO) mice produced less ROS and had less mitochondrial depolarization and damage following the administration of LPS, when compared to their wild-type (WT) counterparts. In addition, IRF-1 KO mice exhibited a decreased release of mitochondrial DNA (mtDNA) following the administration of LPS. Thus, IRF-1 may be a critical factor in augmenting LPS-induced oxidative stress and mitochondrial damage in macrophages. PMID:28849179

Expression of human oxoguanine glycosylase 1 or formamidopyrimidine glycosylase in human embryonic kidney 293 cells exacerbates methylmercury toxicity in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ondovcik, Stephanie L.; Preston, Thomas J.; McCallum, Gordon P.

Exposure to methylmercury (MeHg) acutely at high levels, or via chronic low-level dietary exposure from daily fish consumption, can lead to adverse neurological effects in both the adult and developing conceptus. To determine the impact of variable DNA repair capacity, and the role of reactive oxygen species (ROS) and oxidatively damaged DNA in the mechanism of toxicity, transgenic human embryonic kidney (HEK) 293 cells that stably express either human oxoguanine glycosylase 1 (hOgg1) or its bacterial homolog, formamidopyrimidine glycosylase (Fpg), which primarily repair the oxidative lesion 8-oxo-2′-deoxyguanosine (8-oxodG), were used to assess the in vitro effects of MeHg. Western blottingmore » confirmed the expression of hOgg1 or Fpg in both the nuclear and mitochondrial compartments of their respective cell lines. Following acute (1–2 h) incubations with 0–10 μM MeHg, concentration-dependent decreases in clonogenic survival and cell growth accompanied concentration-dependent increases in lactate dehydrogenase (LDH) release, ROS formation, 8-oxodG levels and apurinic/apyrimidinic (AP) sites, consistent with the onset of cytotoxicity. Paradoxically, hOgg1- and Fpg-expressing HEK 293 cells were more sensitive than wild-type cells stably transfected with the empty vector control to MeHg across all cellular and biochemical parameters, exhibiting reduced clonogenic survival and cell growth, and increased LDH release and DNA damage. Accordingly, upregulation of specific components of the base excision repair (BER) pathway may prove deleterious potentially due to the absence of compensatory enhancement of downstream processes to repair toxic intermediary abasic sites. Thus, interindividual variability in DNA repair activity may constitute an important risk factor for environmentally-initiated, oxidatively damaged DNA and its pathological consequences. - Highlights: • hOgg1 and Fpg repair oxidatively damaged DNA. • hOgg1- and Fpg-expressing cells are more sensitive to MeHg toxicity. • Enhanced sensitivity is likely due to an accumulation of toxic repair intermediates. • Interindividual variability in DNA repair activity may modulate toxicological risk.« less

Oxidative damage in gills and liver in Nile tilapia (Oreochromis niloticus) exposed to diazinon.

PubMed

Toledo-Ibarra, G A; Díaz Resendiz, K J G; Ventura-Ramón, G H; González-Jaime, F; Vega-López, A; Becerril-Villanueva, E; Pavón, L; Girón-Pérez, M I

2016-10-01

Agricultural activity demands the use of pesticides for plague control and extermination. In that matter, diazinon is one of the most widely used organophosphorus pesticides (OPs). Despite its benefits, the use of OPs in agricultural activities can also have negative effects since the excessive use of these substances can represent a major contamination problem for water bodies and organisms that inhabit them. The aim of this paper was to evaluate oxidative damage in lipids and proteins of Nile tilapia (Oreochromis niloticus) exposed acutely to diazinon (0.97, 1.95 and 3.95ppm) for 12 or 24h. The evaluation of oxidative damage was determined by quantifying lipid hydroperoxides (Fox method) and oxidized proteins (DNPH method). The data from this study suggest that diazinon induces a concentration-dependent oxidative damage in proteins, but not lipids, of the liver and gills of Nile tilapia. Furthermore, the treatment leads to a decrease in the concentration of total proteins, which can have serious consequences in cell physiology and fish development. Copyright © 2016 Elsevier Inc. All rights reserved.

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

PubMed

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.

Screening for oxidative damage by engineered nanomaterials: a comparative evaluation of FRAS and DCFH

NASA Astrophysics Data System (ADS)

Pal, Anoop K.; Hsieh, Shu-Feng; Khatri, Madhu; Isaacs, Jacqueline A.; Demokritou, Philip; Gaines, Peter; Schmidt, Daniel F.; Rogers, Eugene J.; Bello, Dhimiter

2014-02-01

Several acellular assays are routinely used to measure oxidative stress elicited by engineered nanomaterials (ENMs), yet little comparative evaluations of such methods exist. This study compares for the first time the performance of the dichlorofluorescein (DCFH) assay which measures reactive oxygen species (ROS) generation, to that of the ferric-reducing ability of serum (FRAS) assay, which measures biological oxidant damage in serum. A diverse set of 28 commercially important and extensively characterized ENMs were tested on both the assays. Intracellular oxidative stress was also assessed on a representative subset of seven ENMs in THP-1 (phorbol 12-myristate 13-acetate matured human monocytes) cells. Associations between assay responses and ENM physicochemical properties were assessed via correlation and regression analysis. DCFH correlated strongly with FRAS after dose normalization for mass ( R 2 = 0.78) and surface area ( R 2 = 0.68). Only 10/28 ENMs were positive in DCFH versus 21/28 in FRAS. Both assays were strongly associated with specific surface area and transition metal content. Qualitatively, a similar response ranking was observed for acellular FRAS and intracellular reduced:oxidized glutathione ratio (GSH:GSSG) in cells. Quantitatively, weak correlation was found between intracellular GSSG and FRAS or DCFH ( R 2 < 0.25) even after calculating effective dose to cells. The FRAS assay was more sensitive than DCFH, especially for ENMs with low to moderate oxidative damage potential, and may serve as a more biologically relevant substitute for acellular ROS measurements of ENMs. Further in vitro and in vivo validations of FRAS against other toxicological endpoints with larger datasets are recommended.

Persistent damaged bases in DNA allow mutagenic break repair in Escherichia coli.

PubMed

Moore, Jessica M; Correa, Raul; Rosenberg, Susan M; Hastings, P J

2017-07-01

Bacteria, yeast and human cancer cells possess mechanisms of mutagenesis upregulated by stress responses. Stress-inducible mutagenesis potentially accelerates adaptation, and may provide important models for mutagenesis that drives cancers, host pathogen interactions, antibiotic resistance and possibly much of evolution generally. In Escherichia coli repair of double-strand breaks (DSBs) becomes mutagenic, using low-fidelity DNA polymerases under the control of the SOS DNA-damage response and RpoS general stress response, which upregulate and allow the action of error-prone DNA polymerases IV (DinB), II and V to make mutations during repair. Pol IV is implied to compete with and replace high-fidelity DNA polymerases at the DSB-repair replisome, causing mutagenesis. We report that up-regulated Pol IV is not sufficient for mutagenic break repair (MBR); damaged bases in the DNA are also required, and that in starvation-stressed cells, these are caused by reactive-oxygen species (ROS). First, MBR is reduced by either ROS-scavenging agents or constitutive activation of oxidative-damage responses, both of which reduce cellular ROS levels. The ROS promote MBR other than by causing DSBs, saturating mismatch repair, oxidizing proteins, or inducing the SOS response or the general stress response. We find that ROS drive MBR through oxidized guanines (8-oxo-dG) in DNA, in that overproduction of a glycosylase that removes 8-oxo-dG from DNA prevents MBR. Further, other damaged DNA bases can substitute for 8-oxo-dG because ROS-scavenged cells resume MBR if either DNA pyrimidine dimers or alkylated bases are induced. We hypothesize that damaged bases in DNA pause the replisome and allow the critical switch from high fidelity to error-prone DNA polymerases in the DSB-repair replisome, thus allowing MBR. The data imply that in addition to the indirect stress-response controlled switch to MBR, a direct cis-acting switch to MBR occurs independently of DNA breakage, caused by ROS oxidation of DNA potentially regulated by ROS regulators.

Persistent damaged bases in DNA allow mutagenic break repair in Escherichia coli

PubMed Central

Moore, Jessica M.; Correa, Raul; Rosenberg, Susan M.

2017-01-01

Bacteria, yeast and human cancer cells possess mechanisms of mutagenesis upregulated by stress responses. Stress-inducible mutagenesis potentially accelerates adaptation, and may provide important models for mutagenesis that drives cancers, host pathogen interactions, antibiotic resistance and possibly much of evolution generally. In Escherichia coli repair of double-strand breaks (DSBs) becomes mutagenic, using low-fidelity DNA polymerases under the control of the SOS DNA-damage response and RpoS general stress response, which upregulate and allow the action of error-prone DNA polymerases IV (DinB), II and V to make mutations during repair. Pol IV is implied to compete with and replace high-fidelity DNA polymerases at the DSB-repair replisome, causing mutagenesis. We report that up-regulated Pol IV is not sufficient for mutagenic break repair (MBR); damaged bases in the DNA are also required, and that in starvation-stressed cells, these are caused by reactive-oxygen species (ROS). First, MBR is reduced by either ROS-scavenging agents or constitutive activation of oxidative-damage responses, both of which reduce cellular ROS levels. The ROS promote MBR other than by causing DSBs, saturating mismatch repair, oxidizing proteins, or inducing the SOS response or the general stress response. We find that ROS drive MBR through oxidized guanines (8-oxo-dG) in DNA, in that overproduction of a glycosylase that removes 8-oxo-dG from DNA prevents MBR. Further, other damaged DNA bases can substitute for 8-oxo-dG because ROS-scavenged cells resume MBR if either DNA pyrimidine dimers or alkylated bases are induced. We hypothesize that damaged bases in DNA pause the replisome and allow the critical switch from high fidelity to error-prone DNA polymerases in the DSB-repair replisome, thus allowing MBR. The data imply that in addition to the indirect stress-response controlled switch to MBR, a direct cis-acting switch to MBR occurs independently of DNA breakage, caused by ROS oxidation of DNA potentially regulated by ROS regulators. PMID:28727736

HMGB1 redox during sepsis.

PubMed

Abdulmahdi, Wasan; Patel, Devika; Rabadi, May M; Azar, Tala; Jules, Edson; Lipphardt, Mark; Hashemiyoon, Rameen; Ratliff, Brian B

2017-10-01

During sepsis, the alarmin HMGB1 is released from tissues and promotes systemic inflammation that results in multi-organ damage, with the kidney particularly susceptible to injury. The severity of inflammation and pro-damage signaling mediated by HMGB1 appears to be dependent on the alarmin's redox state. Therefore, we examined HMGB1 redox in kidney cells during sepsis. Using intravital microscopy, CellROX labeling of kidneys in live mice indicated increased ROS generation in the kidney perivascular endothelium and tubules during lipopolysaccharide (LPS)-induced sepsis. Subsequent CellROX and MitoSOX labeling of LPS-stressed endothelial and kidney proximal tubule cells demonstrated increased ROS generation in these cells as sepsis worsens. Consequently, HMGB1 oxidation increased in the cytoplasm of kidney cells during its translocation from the nucleus to the circulation, with the degree of oxidation dependent on the severity of sepsis, as measured in in vivo mouse samples using a thiol assay and mass spectrometry (LC-MS/MS). The greater the oxidation of HMGB1, the greater the ability of the alarmin to stimulate pro-inflammatory cyto-/chemokine release (measured by Luminex Multiplex) and alter mitochondrial ATP generation (Luminescent ATP Detection Assay). Administration of glutathione and thioredoxin inhibitors to cell cultures enhanced HMGB1 oxidation during sepsis in endothelial and proximal tubule cells, respectively. In conclusion, as sepsis worsens, ROS generation and HMGB1 oxidation increases in kidney cells, which enhances HMGB1's pro-inflammatory signaling. Conversely, the glutathione and thioredoxin systems work to maintain the protein in its reduced state. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

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

PubMed

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 < 0.05), and the correlation between Olive TM and reactive oxygen species was better than other parameters (r = 0.77, P < 0.05). This study indicates that FPG-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 modified comet assay will be used widely in the toxicology and molecular epidemiology study.

Clinical Study of Ursodeoxycholic Acid in Barrett’s Esophagus Patients

PubMed Central

Banerjee, Bhaskar; Shaheen, Nicholas J.; Martinez, Jessica A.; Hsu, Chiu-Hsieh; Trowers, Eugene; Gibson, Blake A.; Della’Zanna, Gary; Richmond, Ellen; Chow, H-H. Sherry

2016-01-01

Prior research strongly implicates gastric acid and bile acids, two major components of the gastroesophageal refluxate, in the development of Barrett’s esophagus (BE) and its pathogenesis. Ursodeoxycholic acid (UDCA), a hydrophilic bile acid, has been shown to protect esophageal cells against oxidative stress induced by cytotoxic bile acids. We conducted a pilot clinical study to evaluate the clinical activity of UDCA in patients with BE. Twenty-nine BE patients received UDCA treatment at a daily dose of 13–15 mg/kg/day for six months. The clinical activity of UDCA was assessed by evaluating changes in gastric bile acid composition and markers of oxidative DNA damage (8-hydroxydeoxyguanosine, 8OHdG), cell proliferation (Ki67), and apoptosis (cleaved caspase 3, CC3) in BE epithelium. The bile acid concentrations in gastric fluid were measured by liquid chromatography-mass spectrometry. At baseline, UDCA (sum of unchanged and glycine/taurine conjugates) accounted for 18.2% of total gastric bile acids. Post UDCA intervention, UDCA increased significantly to account for 93.39% of total gastric bile acids (p<0.0001). The expression of markers of oxidative DNA damage, cell proliferation, and apoptosis was assessed in the BE biopsies by immunohistochemistry. The selected tissue biomarkers were unchanged after 6 months of UDCA intervention. We conclude that high dose UDCA supplementation for six months resulted in favorable changes in gastric bile acid composition but did not modulate selected markers of oxidative DNA damage, cell proliferation, and apoptosis in the BE epithelium. PMID:26908564

Trifluoroacetylated tyrosine-rich D-tetrapeptides have potent antioxidant activity.

PubMed

Sandomenico, Annamaria; Severino, Valeria; Apone, Fabio; De Lucia, Adriana; Caporale, Andrea; Doti, Nunzianna; Russo, Anna; Russo, Rosita; Rega, Camilla; Del Giacco, Tiziana; Falcigno, Lucia; Ruvo, Menotti; Chambery, Angela

2017-03-01

The term "oxidative stress" indicates a set of chemical reactions unleashed by a disparate number of events inducing DNA damage, lipid peroxidation, protein modification and other effects, which are responsible of altering the physiological status of cells or tissues. Excessive Reactive Oxygen Species (ROS) levels may accelerate ageing of tissues or induce damage of biomolecules thus promoting cell death or proliferation in dependence of cell status and of targeted molecules. In this context, new antioxidants preventing such effects may have a relevant role as modulators of cell homeostasis and as therapeutic agents. Following an approach of peptide libraries synthesis and screening by an ORAC FL assay, we have isolated potent anti-oxidant compounds with well-defined structures. Most effective peptides are N-terminally trifluoroacetylated (CF 3 ) and have the sequence tyr-tyr-his-pro or tyr-tyr-pro-his. Slight changes in the sequence or removal of the CF 3 group strongly reduced antioxidant ability, suggesting an active role of both the fluorine atoms and of peptide structure. We have determined the NMR solution structures of the active peptides and found a common structural motif that could underpin the radical scavenging activity. The peptides protect keratinocytes from exogenous oxidation, thereby from potential external damaging cues, suggesting their use as skin ageing protectant and as cell surviving agents. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

PubMed

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 hypertrophy and senescence. Indeed, GSK3β inactivation is responsible for ROS production, triggering oxidative stress and DNA damage response.

Metal-accelerated oxidation in plant cell death

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czuba, M.

1993-05-01

Cadmium and mercury toxicity is further enhanced by external oxidizing conditions O[sub 3] or inherent plant processes. Lepidium sativum L, Lycopersicon esculentum Mill., or Phaseolus vulgaris L, were grown inpeat-lite to maturity under continuous cadmium exposure followed by one oxidant (O[sub 3]-6 hr. 30 pphm) exposure, with or without foliar calcium pretreatments. In comparison, Daucus carota, L and other species grown in a 71-V suspension, with or without 2,4-D were exposed continuously to low levels of methylmercury during exponential growth and analyzed in aggregates of distinct populations. Proteins were extracted and analyzed. Mechanisms of toxicity and eventual cell death aremore » Ca-mediated and involve chloroplast, stomatal-water relations and changes in oxidant-anti-oxidant components in cells. Whether the metal-accelerated oxidative damage proceeds to cell death, depends on the species and its differential biotransformation system and cell association component.« less

Low-concentration exposure to BPA, BPF and BPAF induces oxidative DNA bases lesions in human peripheral blood mononuclear cells.

PubMed

Mokra, Katarzyna; Woźniak, Katarzyna; Bukowska, Bożena; Sicińska, Paulina; Michałowicz, Jaromir

2018-06-01

Because bisphenol A (BPA) and some of its analogs have been supposed to influence development of cancer, we have assessed the effect of BPA, bisphenol S (BPS), bisphenol F (BPF) and bisphenol AF (BPAF) on DNA bases oxidation, which is a key process in cancer initiation. The analysis was conducted on human peripheral blood mononuclear cells (PBMCs), which are very useful model to assess genotoxic potential of various toxicants in different cell types. In order to determine oxidative damage to DNA pyrimidines and purines, alkaline version of the comet assay with DNA glycosylases, i.e. endonuclease III (Nth) and human 8-oxoguanine DNA glycosylase (hOGG1) was used. PBMCs were exposed to BPA or its analogs in the concentrations of 0.01, 0.1 and 1 μg/mL for 4 h and 0.001, 0.01 and 0.1 μg/mL for 48 h. We have observed that BPA, BPS, BPF and particularly BPAF caused oxidative damage to DNA pyrimidines and more strongly to purines in human PBMCs. The results have also shown that BPS, which is the most commonly used as a substitute for BPA in the manufacture induced definitely the smallest oxidative DNA bases lesions in PBMCs. Moreover, we have noticed that BPA, BPF and BPAF caused DNA damage at very low concentration of 1 ng/mL. Copyright © 2018 Elsevier Ltd. All rights reserved.

Protective effect and mechanism of glutaredoxin 1 on coronary arteries endothelial cells damage induced by high glucose.

PubMed

Li, Shuyan; Sun, Yan; Qi, Xiaodan; Shi, Yan; Gao, Han; Wu, Qi; Liu, Xiucai; Yu, Haitao; Zhang, Chunjing

2014-01-01

In recent years, diabetes and its associated complications have become a major public health concern. The cardiovascular risk increases significantly in diabetes patients. It is a complex disease characterized by multiple metabolic derangements and is known to impair cardiac function by disrupting the balance between pro-oxidants and antioxidants at the cellular level. The subsequent generation of reactive oxygen species (ROS) and accompanying oxidative stress are hallmarks of the molecular mechanisms responsible for cardiovascular disease. Protein thiols act as redox-sensitive switches and are believed to be a key element in maintaining the cellular redox balance. The redox state of protein thiols is regulated by oxidative stress and redox signaling and is important to cellular functions. The potential of the thiol-disulfide oxidoreductase enzymes (thioredoxin and glutaredoxin systems) in defense against oxidative stress has been noted previously. Increasing evidence demonstrates that glutaredoxin 1 (Grx1), a cytosolic enzyme responsible for the catalysis of protein deglutathionylation, plays distinct roles in inflammation and apoptosis by inducing changes in the cellular redox system. This study investigates whether and how Grx1 protects coronary artery vascular endothelial cells against high glucose (HG) induced damage. Results indicate that the activation of eNOS/NO system is regulated by Grx 1 and coupled with inhibition of JNK and NF-κB signaling pathway which could alleviate the oxidative stress and apoptosis damage in coronary arteries endothelial cells induced by HG.

Chlorogenic acid improves ex vivo vessel function and protects endothelial cells against HOCl-induced oxidative damage, via increased production of nitric oxide and induction of Hmox-1.

PubMed

Jiang, Rujia; Hodgson, Jonathan M; Mas, Emilie; Croft, Kevin D; Ward, Natalie C

2016-01-01

Dietary polyphenols are potential contributors toward improved cardiovascular health. Coffee is one of the richest sources of dietary polyphenols in a coffee-drinking population, the most abundant form being chlorogenic acid (CGA). Endothelial dysfunction is an early and major risk factor for cardiovascular disease. Nitric oxide (NO) is a key factor in regulation of endothelial function. Heme oxygenase-1 (Hmox-1), an inducible isoform of heme oxygenase that is produced in response to stressors such as oxidative stress, may also play a role in vascular protection. The aim of this study was to investigate the effect of CGA on endothelial function with oxidant-induced damage in isolated aortic rings from C57BL mice. We further examine the mechanism by investigating cell viability, activation of eNOS and induction of Hmox-1 in human aortic endothelial cells (HAECs). We found that pretreatment of isolated aortic rings with 10-μM CGA-protected vessels against HOCl-induced endothelial dysfunction (P<0.05). Pretreatment of cultured HAECs with 10-μM CGA increased endothelial cell viability following exposure to HOCl (P<0.05). Moreover, CGA increased NO production in HAECs in a dose-dependent manner, peaking at 6 h (P<0.05). CGA at 5 μM and 10 μM increased eNOS dimerization at 6 h and induced Hmox-1 protein expression at 6 h and 24 h in HAECs. These results are consistent with the cardiovascular protective effects of coffee polyphenols and demonstrate that CGA can protect vessels and cultured endothelial cells against oxidant-induced damage. The mechanism behind the beneficial effect of CGA appears to be in part via increased production of NO and induction of Hmox-1. Copyright © 2015 Elsevier Inc. All rights reserved.

A Single Zidovudine (AZT) Administration Delays Hepatic Cell Proliferation by Altering Oxidative State in the Regenerating Rat Liver.

PubMed

Butanda-Ochoa, Armando; Hernández-Espinosa, Diego Rolando; Olguín-Martínez, Marisela; Sánchez-Sevilla, Lourdes; Rodríguez, Mario R; Chávez-Rentería, Benito; Aranda-Fraustro, Alberto; Hernández-Muñoz, Rolando

2017-01-01

The 3'-azido-3'-deoxythymidine or Zidovudine (AZT) was the first antiretroviral drug used in the treatment of HIV patients, which has good effectiveness but also hepatotoxic side effects that include cell cycle arrest and oxidative/nitrative mitochondrial damage. Whether such an oxidative damage may affect the proliferative-regenerative capacity of liver remains to be clearly specified at doses commonly used in the clinical practice. In this study, we described the oxidative-proliferative effect of AZT administered at a common clinical dose in rat liver submitted to 70% partial hepatectomy (PH). The results indicate that AZT significantly decreased DNA synthesis and the number of mitosis in liver subjected to PH in a synchronized way with the promotion of organelle-selective lipid peroxidation events (especially those observed in plasma membrane and cytosolic fractions) and with liver enzyme release to the bloodstream. Then at the dose used in clinical practice AZT decreased liver regeneration but stimulates oxidative events involved during the proliferation process in a way that each membrane system inside the cell preserves its integrity in order to maintain the cell proliferative process. Here, the induction of large amounts of free ammonia in the systemic circulation could become a factor capable of mediating the deleterious effects of AZT on PH-induced rat liver regeneration.

In Vitro Fluorogenic Real-time Assay of the Repair of Oxidative DNA Damage

PubMed Central

Edwards, Sarah K.; Ono, Toshikazu; Wang, Shenliang; Jiang, Wei; Franzini, Raphael M.; Jung, Jong Wha; Chan, Ke Min; Kool, Eric T.

2015-01-01

The repair of oxidative damage to DNA is essential to avoidance of mutations that lead to cancer. Oxidized DNA bases, such as 8-oxoguanine, are a chief source of these mutations, and the enzyme 8-oxoguanine glycosylase 1 (OGG1) is the chief human enzyme that excises 8-oxoguanine from DNA. The activity of OGG1 has been linked to human inflammation responses and to cancer, and researchers are beginning to search for inhibitors of the enzyme. However, measuring the activity of the enzyme typically requires laborious gel-based measurements of radiolabeled DNAs. Here we report on the design and properties of fluorogenic probes that directly report on OGG1 (and bacterial homologue Fpg) activity in real time as the oxidized base is excised. The probes are short modified DNA oligomers containing fluorescent DNA bases and are designed to utilize the damaged DNA base itself as a fluorescence quencher. Screening of combinations of fluorophores and 8-oxoguanine revealed two fluorophores, pyrene and tCo, that are strongly quenched by the damaged base. We tested 42 potential probe designs containing these fluorophores, and we found an optimized probe OGR1 that yields a 60-fold light-up signal in vitro with OGG1 and Fpg, and can report on oxidative repair activity in mammalian cell lysate and with bacterial cells overexpressing a repair enzyme. Such probes may be useful in quantifying enzyme activity and performing competitive inhibition assays. PMID:26073452

Superoxide Dismutase (SOD)-mimetic M40403 Is Protective in Cell and Fly Models of Paraquat Toxicity

PubMed Central

Filograna, Roberta; Godena, Vinay K.; Sanchez-Martinez, Alvaro; Ferrari, Emanuele; Casella, Luigi; Beltramini, Mariano; Bubacco, Luigi; Whitworth, Alexander J.; Bisaglia, Marco

2016-01-01

Parkinson disease is a debilitating and incurable neurodegenerative disorder affecting ∼1–2% of people over 65 years of age. Oxidative damage is considered to play a central role in the progression of Parkinson disease and strong evidence links chronic exposure to the pesticide paraquat with the incidence of the disease, most probably through the generation of oxidative damage. In this work, we demonstrated in human SH-SY5Y neuroblastoma cells the beneficial role of superoxide dismutase (SOD) enzymes against paraquat-induced toxicity, as well as the therapeutic potential of the SOD-mimetic compound M40403. Having verified the beneficial effects of superoxide dismutation in cells, we then evaluated the effects using Drosophila melanogaster as an in vivo model. Besides protecting against the oxidative damage induced by paraquat treatment, our data demonstrated that in Drosophila M40403 was able to compensate for the loss of endogenous SOD enzymes, acting both at a cytosolic and mitochondrial level. Because previous clinical trials have indicated that the M40403 molecule is well tolerated in humans, this study may have important implication for the treatment of Parkinson disease. PMID:26953346

Systemic inflammation and oxidative stress post-lung resection: Effect of pretreatment with N-acetylcysteine.

PubMed

Bastin, Anthony J; Davies, Nathan; Lim, Eric; Quinlan, Greg J; Griffiths, Mark J

2016-01-01

N-acetylcysteine has been used to treat a variety of lung diseases, where is it thought to have an antioxidant effect. In a randomized placebo-controlled double-blind study, the effect of N-acetylcysteine on systemic inflammation and oxidative damage was examined in patients undergoing lung resection, a human model of acute lung injury. Eligible adults were randomized to receive preoperative infusion of N-acetylcysteine (240 mg/kg over 12 h) or placebo. Plasma thiols, interleukin-6, 8-isoprostane, ischaemia-modified albumin, red blood cell glutathione and exhaled breath condensate pH were measured pre- and post-operatively as markers of local and systemic inflammation and oxidative stress. Patients undergoing lung resection and one-lung ventilation exhibited significant postoperative inflammation and oxidative damage. Postoperative plasma thiol concentration was significantly higher in the N-acetylcysteine-treated group. However, there was no significant difference in any of the measured biomarkers of inflammation or oxidative damage, or in clinical outcomes, between N-acetylcysteine and placebo groups. Preoperative administration of N-acetylcysteine did not attenuate postoperative systemic or pulmonary inflammation or oxidative damage after lung resection. NCT00655928 at ClinicalTrials.gov. © 2015 Asian Pacific Society of Respirology.

Cholesterol Hydroperoxide Generation, Translocation, and Reductive Turnover in Biological Systems.

PubMed

Girotti, Albert W; Korytowski, Witold

2017-12-01

Cholesterol is like other unsaturated lipids in being susceptible to peroxidative degradation upon exposure to strong oxidants like hydroxyl radical or peroxynitrite generated under conditions of oxidative stress. In the eukaryotic cell plasma membrane, where most of the cellular cholesterol resides, peroxidation leads to membrane structural and functional damage from which pathological states may arise. In low density lipoprotein, cholesterol and phospholipid peroxidation have long been associated with atherogenesis. Among the many intermediates/products of cholesterol oxidation, hydroperoxide species (ChOOHs) have a number of different fates and deserve special attention. These fates include (a) damage-enhancement via iron-catalyzed one-electron reduction, (b) damage containment via two-electron reduction, and (c) inter-membrane, inter-lipoprotein, and membrane-lipoprotein translocation, which allows dissemination of one-electron damage or off-site suppression thereof depending on antioxidant location and capacity. In addition, ChOOHs can serve as reliable and conveniently detected mechanistic reporters of free radical-mediated reactions vs. non-radical (e.g., singlet oxygen)-mediated reactions. Iron-stimulated peroxidation of cholesterol and other lipids underlies a newly discovered form of regulated cell death called ferroptosis. These and other deleterious consequences of radical-mediated lipid peroxidation will be discussed in this review.

Skin cell protection against UVA by Sideroxyl, a new antioxidant complementary to sunscreens.

PubMed

Pygmalion, Marie-Jocelyne; Ruiz, Laetitia; Popovic, Evelyne; Gizard, Julie; Portes, Pascal; Marat, Xavier; Lucet-Levannier, Karine; Muller, Benoit; Galey, Jean-Baptiste

2010-12-01

Oxidative stress resulting from photosensitized ROS production in skin is widely accepted as the main contributor to the deleterious effects of UVA exposure. Among the mechanisms known to be involved in UVA-induced oxidative damage, iron plays a central role. UVA radiation of skin cells induces an immediate release of iron, which can then act as a catalyst for uncontrolled oxidation reactions of cell components. Such site-specific damage can scarcely be counteracted by classical antioxidants. In contrast, iron chelators potentially offer an effective way to protect skin against UVA insults. However, iron chelation is very difficult to achieve without disturbing iron homeostasis or inducing iron depletion. A novel compound was developed to avoid these potentially harmful side effects. Sideroxyl was designed to acquire its strong chelating capability only during oxidative stress according to an original process of intramolecular hydroxylation. Herein, we describe in vitro results demonstrating the protective efficiency of Sideroxyl against deleterious effects of UVA at the molecular, cellular, and tissular levels. First, the Sideroxyl diacid form protects a model protein against UVA-induced photosensitized carbonylation. Second, intracellular ROS are dose-dependently decreased in the presence of Sideroxyl in both human cultured fibroblasts and human keratinocytes. Third, Sideroxyl protects normal human fibroblasts against UVA-induced DNA damage as measured by the comet assay and MMP-1 production. Finally, Sideroxyl provides protection against UVA-induced alterations in human reconstructed skin. These results suggest that Sideroxyl may prevent UVA-induced damage in human skin as a complement to sunscreens, especially in the long-wavelength UVA range. Copyright © 2010 Elsevier Inc. All rights reserved.

Reactive oxygen species, oxidative stress, glaucoma and hyperbaric oxygen therapy.

PubMed

McMonnies, Charles

This review examines the role of oxidative stress in damage to cells of the trabecular meshwork and associated impaired aqueous drainage as well as damage to retinal ganglion cells and associated visual field losses. Consideration is given to the interaction between vascular and mechanical explanations for pathological changes in glaucoma. For example, elevated intraocular pressure (IOP) forces may contribute to ischaemia but there is increasing evidence that altered blood flow in a wider sense is also involved. Both vascular and mechanical theories are involved through fluctuations in intraocular pressure and dysregulation of blood flow. Retinal function is very sensitive to changes in haemoglobin oxygen concentration and the associated variations in the production of reactive oxygen species. Reperfusion injury and production of reactive oxygen species occurs when IOP is elevated or blood pressure is low and beyond the capacity for blood flow autoregulation to maintain appropriate oxygen concentration. Activities such as those associated with postural changes, muscular effort, eye wiping and rubbing which cause IOP fluctuation, may have significant vascular, mechanical, reperfusion and oxidative stress consequences. Hyperbaric oxygen therapy exposes the eye to increased oxygen concentration and the risk of oxidative damage in susceptible individuals. However, oxygen concentration in aqueous humour, and the risk of damage to trabecular meshwork cells may be greater if hyperbaric oxygen is delivered by a hood which exposes the anterior ocular surface to higher than normal oxygen levels. Oronasal mask delivery of hyperbaric oxygen therapy appears to be indicated in these cases. Copyright © 2017 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

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

PubMed Central

Habib, Samy L.; Liang, Sitai

2014-01-01

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. PMID:24797175

BID links ferroptosis to mitochondrial cell death pathways.

PubMed

Neitemeier, Sandra; Jelinek, Anja; Laino, Vincenzo; Hoffmann, Lena; Eisenbach, Ina; Eying, Roman; Ganjam, Goutham K; Dolga, Amalia M; Oppermann, Sina; Culmsee, Carsten

2017-08-01

Ferroptosis has been defined as an oxidative and iron-dependent pathway of regulated cell death that is distinct from caspase-dependent apoptosis and established pathways of death receptor-mediated regulated necrosis. While emerging evidence linked features of ferroptosis induced e.g. by erastin-mediated inhibition of the X c - system or inhibition of glutathione peroxidase 4 (Gpx4) to an increasing number of oxidative cell death paradigms in cancer cells, neurons or kidney cells, the biochemical pathways of oxidative cell death remained largely unclear. In particular, the role of mitochondrial damage in paradigms of ferroptosis needs further investigation. In the present study, we find that erastin-induced ferroptosis in neuronal cells was accompanied by BID transactivation to mitochondria, loss of mitochondrial membrane potential, enhanced mitochondrial fragmentation and reduced ATP levels. These hallmarks of mitochondrial demise are also established features of oxytosis, a paradigm of cell death induced by X c - inhibition by millimolar concentrations of glutamate. Bid knockout using CRISPR/Cas9 approaches preserved mitochondrial integrity and function, and mediated neuroprotective effects against both, ferroptosis and oxytosis. Furthermore, the BID-inhibitor BI-6c9 inhibited erastin-induced ferroptosis, and, in turn, the ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 prevented mitochondrial dysfunction and cell death in the paradigm of oxytosis. These findings show that mitochondrial transactivation of BID links ferroptosis to mitochondrial damage as the final execution step in this paradigm of oxidative cell death. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

De-Differentiation Confers Multidrug Resistance Via Noncanonical PERK-Nrf2 Signaling

PubMed Central

Del Vecchio, Catherine A.; Feng, Yuxiong; Sokol, Ethan S.; Tillman, Erik J.; Sanduja, Sandhya; Reinhardt, Ferenc; Gupta, Piyush B.

2014-01-01

Malignant carcinomas that recur following therapy are typically de-differentiated and multidrug resistant (MDR). De-differentiated cancer cells acquire MDR by up-regulating reactive oxygen species (ROS)–scavenging enzymes and drug efflux pumps, but how these genes are up-regulated in response to de-differentiation is not known. Here, we examine this question by using global transcriptional profiling to identify ROS-induced genes that are already up-regulated in de-differentiated cells, even in the absence of oxidative damage. Using this approach, we found that the Nrf2 transcription factor, which is the master regulator of cellular responses to oxidative stress, is preactivated in de-differentiated cells. In de-differentiated cells, Nrf2 is not activated by oxidation but rather through a noncanonical mechanism involving its phosphorylation by the ER membrane kinase PERK. In contrast, differentiated cells require oxidative damage to activate Nrf2. Constitutive PERK-Nrf2 signaling protects de-differentiated cells from chemotherapy by reducing ROS levels and increasing drug efflux. These findings are validated in therapy-resistant basal breast cancer cell lines and animal models, where inhibition of the PERK-Nrf2 signaling axis reversed the MDR of de-differentiated cancer cells. Additionally, analysis of patient tumor datasets showed that a PERK pathway signature correlates strongly with chemotherapy resistance, tumor grade, and overall survival. Collectively, these results indicate that de-differentiated cells up-regulate MDR genes via PERK-Nrf2 signaling and suggest that targeting this pathway could sensitize drug-resistant cells to chemotherapy. PMID:25203443

Salvianolic Acid B (Sal B) Protects Retinal Pigment Epithelial Cells from Oxidative Stress-Induced Cell Death by Activating Glutaredoxin 1 (Grx1)

PubMed Central

Liu, Xiaobin; Xavier, Christy; Jann, Jamieson; Wu, Hongli

2016-01-01

Protein glutathionylation, defined as the formation of protein mixed disulfides (PSSG) between cysteine residues and glutathione (GSH), can lead to cell death. Glutaredoxin 1 (Grx1) is a thiol repair enzyme which catalyzes the reduction of PSSG. Therefore, Grx1 exerts strong anti-apoptotic effects by improving the redox state, especially in times of oxidative stress. However, there is currently no compound that is identified as a Grx1 activator. In this study, we identified and characterized Salvianolic acid B (Sal B), a natural compound, as a Grx1 inducer, which potently protected retinal pigment epithelial (RPE) cells from oxidative injury. Our results showed that treatment with Sal B protected primary human RPE cells from H2O2-induced cell damage. Interestingly, we found Sal B pretreatment upregulated Grx1 expression in RPE cells in a time- and dose-dependent manner. Furthermore, NF-E2-related factor 2 (Nrf2), the key transcription factor that regulates the expression of Grx1, was activated in Sal B treated RPE cells. Further investigation showed that knockdown of Grx1 by small interfering RNA (siRNA) significantly reduced the protective effects of Sal B. We conclude that Sal B protects RPE cells against H2O2-induced cell injury through Grx1 induction by activating Nrf2 pathway, thus preventing lethal accumulation of PSSG and reversing oxidative damage. PMID:27827892

Redox signaling via the molecular chaperone BiP protects cells against endoplasmic reticulum-derived oxidative stress

PubMed Central

Wang, Jie; Pareja, Kristeen A; Kaiser, Chris A; Sevier, Carolyn S

2014-01-01

Oxidative protein folding in the endoplasmic reticulum (ER) has emerged as a potentially significant source of cellular reactive oxygen species (ROS). Recent studies suggest that levels of ROS generated as a byproduct of oxidative folding rival those produced by mitochondrial respiration. Mechanisms that protect cells against oxidant accumulation within the ER have begun to be elucidated yet many questions still remain regarding how cells prevent oxidant-induced damage from ER folding events. Here we report a new role for a central well-characterized player in ER homeostasis as a direct sensor of ER redox imbalance. Specifically we show that a conserved cysteine in the lumenal chaperone BiP is susceptible to oxidation by peroxide, and we demonstrate that oxidation of this conserved cysteine disrupts BiP's ATPase cycle. We propose that alteration of BiP activity upon oxidation helps cells cope with disruption to oxidative folding within the ER during oxidative stress. DOI: http://dx.doi.org/10.7554/eLife.03496.001 PMID:25053742

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.

PubMed

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 copper accumulation in the cytoplasm and the nucleus. Modulation of gene expression by CuO NP appeared to be primarily oxidative stress-related and was more pronounced in redox-sensitive BEAS-2B cells. Regarding CuCl 2 , relevant modulations of gene expression were restricted to cytotoxic concentrations provoking impaired copper homoeostasis.

Redox signaling is an early event in the pathogenesis of renovascular hypertension.

PubMed

Hartono, Stella P; Knudsen, Bruce E; Zubair, Adeel S; Nath, Karl A; Textor, Stephen J; Lerman, Lilach O; Grande, Joseph P

2013-09-10

Activation of the renin-angiotensin-aldosterone system plays a critical role in the development of chronic renal damage in patients with renovascular hypertension. Although angiotensin II (Ang II) promotes oxidative stress, inflammation, and fibrosis, it is not known how these pathways intersect to produce chronic renal damage. We tested the hypothesis that renal parenchymal cells are subjected to oxidant stress early in the development of RVH and produce signals that promote influx of inflammatory cells, which may then propagate chronic renal injury. We established a reproducible murine model of RVH by placing a tetrafluoroethylene cuff on the right renal artery. Three days after cuff placement, renal tissue demonstrates no histologic abnormalities despite up regulation of both pro- and anti-oxidant genes. Mild renal atrophy was observed after seven days and was associated with induction of Tnfα and influx of CD3⁺ T cells and F4/80⁺ macrophages. By 28 days, kidneys developed severe renal atrophy with interstitial inflammation and fibrosis, despite normalization of plasma renin activity. Based on these considerations, we propose that renal parenchymal cells initiate a progressive cascade of events leading to oxidative stress, interstitial inflammation, renal fibrosis, and atrophy.

Hyperoside prevents oxidative damage induced by hydrogen peroxide in lung fibroblast cells via an antioxidant effect.

PubMed

Piao, Mei Jing; Kang, Kyoung Ah; Zhang, Rui; Ko, Dong Ok; Wang, Zhi Hong; You, Ho Jin; Kim, Hee Sun; Kim, Ju Sun; Kang, Sam Sik; Hyun, Jin Won

2008-12-01

We elucidated the cytoprotective effects of hyperoside (quercetin-3-O-galactoside) against hydrogen peroxide (H2O2)-induced cell damage. We found that hyperoside scavenged the intracellular reactive oxygen species (ROS) detected by fluorescence spectrometry, flow cytometry, and confocal microscopy. In addition, we found that hyperoside scavenged the hydroxyl radicals generated by the Fenton reaction (FeSO4)+H2O2) in a cell-free system, which was detected by electron spin resonance (ESR) spectrometry. Hyperoside was found to inhibit H2O2-induced apoptosis in Chinese hamster lung fibroblast (V79-4) cells, as shown by decreased apoptotic nuclear fragmentation, decreased sub-G(1) cell population, and decreased DNA fragmentation. In addition, hyperoside pretreatment inhibited the H2O2-induced activation of caspase-3 measured in terms of levels of cleaved caspase-3. Hyperoside prevented H2O2-induced lipid peroxidation as well as protein carbonyl. In addition, hyperoside prevented the H2O2-induced cellular DNA damage, which was established by comet tail, and phospho histone H2A.X expression. Furthermore, hyperoside increased the catalase and glutathione peroxidase activities. Conversely, the catalase inhibitor abolished the cytoprotective effect of hyperoside from H2O2-induced cell damage. In conclusion, hyperoside was shown to possess cytoprotective properties against oxidative stress by scavenging intracellular ROS and enhancing antioxidant enzyme activity.

The use of comet assay in plant toxicology: recent advances

PubMed Central

Santos, Conceição L. V.; Pourrut, Bertrand; Ferreira de Oliveira, José M. P.

2015-01-01

The systematic study of genotoxicity in plants induced by contaminants and other stress agents has been hindered to date by the lack of reliable and robust biomarkers. The comet assay is a versatile and sensitive method for the evaluation of DNA damages and DNA repair capacity at single-cell level. Due to its simplicity and sensitivity, and the small number of cells required to obtain robust results, the use of plant comet assay has drastically increased in the last decade. For years its use was restricted to a few model species, e.g., Allium cepa, Nicotiana tabacum, Vicia faba, or Arabidopsis thaliana but this number largely increased in the last years. Plant comet assay has been used to study the genotoxic impact of radiation, chemicals including pesticides, phytocompounds, heavy metals, nanoparticles or contaminated complex matrices. Here we will review the most recent data on the use of this technique as a standard approach for studying the genotoxic effects of different stress conditions on plants. Also, we will discuss the integration of information provided by the comet assay with other DNA-damage indicators, and with cellular responses including oxidative stress, cell division or cell death. Finally, we will focus on putative relations between transcripts related with DNA damage pathways, DNA replication and repair, oxidative stress and cell cycle progression that have been identified in plant cells with comet assays demonstrating DNA damage. PMID:26175750

Chlorella protects against hydrogen peroxide-induced pancreatic β-cell damage.

PubMed

Lin, Chia-Yu; Huang, Pei-Jane; Chao, Che-Yi

2014-12-01

Oxidative stress has been implicated in the etiology of pancreatic β-cell dysfunction and diabetes. Studies have shown that chlorella could be important in health promotion or disease prevention through its antioxidant capacity. However, whether chlorella has a cytoprotective effect in pancreatic β-cells remains to be elucidated. We investigated the protective effects of chlorella on H2O2-induced oxidative damage in INS-1 (832/13) cells. Chlorella partially restored cell viability after H2O2 toxicity. To further investigate the effects of chlorella on mitochondria function and cellular oxidative stress, we analyzed mitochondria membrane potential, ATP concentrations, and cellular levels of reactive oxygen species (ROS). Chlorella prevented mitochondria disruption and maintained cellular ATP levels after H2O2 toxicity. It also normalized intracellular levels of ROS to that of control in the presence of H2O2. Chlorella protected cells from apoptosis as indicated by less p-Histone and caspase 3 activation. In addition, chlorella not only enhanced glucose-stimulated insulin secretion (GSIS), but also partially restored the reduced GSIS after H2O2 toxicity. Our results suggest that chlorella is effective in amelioration of cellular oxidative stress and destruction, and therefore protects INS-1 (832/13) cells from H2O2-induced apoptosis and increases insulin secretion. Chlorella should be studied for use in the prevention or treatment of diabetes.

Is Liver Enzyme Release Really Associated with Cell Necrosis Induced by Oxidant Stress?

PubMed

Contreras-Zentella, Martha Lucinda; Hernández-Muñoz, Rolando

2016-01-01

Hepatic diseases are a major concern worldwide. Increased specific plasma enzyme activities are considered diagnostic features for liver diseases, since enzymes are released into the blood compartment following the deterioration of the organ. Release of liver mitochondrial enzymes is considered strong evidence for hepatic necrosis, which is associated with an increased production of ROS, often leading to greater hepatic lipid peroxidation. Lipotoxic mediators and intracellular signals activated Kupffer cells, which provides evidence strongly suggesting the participation of oxidant stress in acute liver damage, inducing the progression of liver injury to chronic liver damage. Elevated transaminase activities are considered as an index marker of hepatotoxicity, linked to oxidant stress. However, a drastic increase of serum activities of liver enzyme markers ought not necessarily to reflect liver cell death. In fact, increased serum levels of cytoplasmic enzymes have readily been observed after partial hepatectomy (PH) in the regenerating liver of rats. In this regard, we are now showing that in vitro modifications of the oxidant status affect differentially the release of liver enzymes, indicating that this release is a strictly controlled event and not directly related to the onset of oxidant stress of the liver.

The Effect of Ozone on Colonic Epithelial Cells.

PubMed

Himuro, Hidetomo

2018-05-21

Due to its strong oxidation activity, ozone has been well known to kill bacteria and exert toxic effects on human tissues. At the same time, ozone is being used for the treatment of diseases such as inflammatory bowel disease in some European countries. However, the use of ozone for therapeutic purposes, despite its strong toxic effects, remains largely unexplored. Interestingly, we found that intrarectal administration of ozone gas induced transient colonic epithelial cell damage characterized by the impairment of cell survival pathways involved in DNA replication, cell cycle, and mismatch repair. However, the damaged cells were rapidly extruded from the epithelial layer, and appeared to immediately stimulate turnover of the epithelial layer in the colon. Therefore, it is possible that ozone gas is able to trigger damage-induced rapid regeneration of intestinal epithelial cells, and that this explains why ozone does not cause harmful or persistent damage in the colon.

The Greenland shark: A new challenge for the oxidative stress theory of ageing?

PubMed

Costantini, David; Smith, Shona; Killen, Shaun S; Nielsen, Julius; Steffensen, John F

2017-01-01

The free radical theory of ageing predicts that long-lived species should be more resistant to oxidative damage than short-lived species. Although many studies support this theory, recent studies found notable exceptions that challenge the generality of this theory. In this study, we have analysed the oxidative status of the Greenland shark (Somniosus microcephalus), which has recently been found as the longest living vertebrate animal known to science with a lifespan of at least 272years. As compared to other species, the Greenland shark had body mass-corrected values of muscle glutathione peroxidase and red blood cells protein carbonyls (metric of protein oxidative damage) above 75 percentile and below 25 percentile, respectively. None of the biochemical metrics of oxidative status measured in either skeletal muscle or red blood cells were correlated with maximum lifespan of species. We propose that the values of metrics of oxidative status we measured might be linked to ecological features (e.g., adaptation to cold waters and deep dives) of this shark species rather to its lifespan. Copyright © 2016 Elsevier Inc. All rights reserved.

Dietary broccoli sprouts protect against myocardial oxidative damage and cell death during ischemia-reperfusion.

PubMed

Akhlaghi, Masoumeh; Bandy, Brian

2010-09-01

Cruciferous vegetables are known for antioxidant and anti-carcinogenic effects. In the current study we asked whether dietary broccoli sprouts can protect the heart from ischemia-reperfusion. Rats were fed either control diet (sham and control groups) or a diet mixed with 2% dried broccoli sprouts for 10 days. After 10 days the isolated hearts were subjected to ischemia for 20 min and reperfusion for 2 h, and evaluated for cell death, oxidative damage, and Nrf2-regulated phase 2 enzyme activities. Broccoli sprouts feeding inhibited markers of necrosis (lactate dehydrogenase release) and apoptosis (caspase-3 activity) by 78-86%, and decreased indices of oxidative stress (thiobarbituric acid reactive substances and aconitase inactivation) by 82-116%. While broccoli sprouts increased total glutathione and activities of the phase 2 enzymes glutamate cysteine ligase and quinone reductase in liver, they did not affect these in ischemic-reperfused heart. While the mechanism is not clear, the results show that a relatively short dietary treatment with broccoli sprouts can strongly protect the heart against oxidative stress and cell death caused by ischemia-reperfusion.

Protective effect of Pterostilbene against free radical mediated oxidative damage

PubMed Central

2013-01-01

Background Pterostilbene, a methoxylated analog of Resveratrol, is gradually gaining more importance as a therapeutic drug owing to its higher lipophilicity, bioavailability and biological activity than Resveratrol. This study was undertaken to characterize its ability to scavenge free radicals such as superoxide, hydroxyl and hydrogen peroxide and to protect bio-molecules within a cell against oxidative insult. Methods Anti-oxidant activity of Pterostilbene was evaluated extensively by employing several in vitro radical scavenging/inhibiting assays and pulse radiolysis study. In addition, its ability to protect rat liver mitochondria against tertiary-butyl hydroperoxide (TBHP) and hydroxyl radical generated oxidative damage was determined by measuring the damage markers such as protein carbonyls, protein sulphydryls, lipid hydroperoxides, lipid peroxides and 8-hydroxy-2'-deoxyguanosine. Pterostilbene was also evaluated for its ability to inhibit •OH radical induced single strand breaks in pBR322 DNA. Result Pterostilbene exhibited strong anti-oxidant activity against various free radicals such as DPPH, ABTS, hydroxyl, superoxide and hydrogen peroxide in a concentration dependent manner. Pterostilbene conferred protection to proteins, lipids and DNA in isolated mitochondrial fractions against TBHP and hydroxyl radical induced oxidative damage. It also protected pBR322 DNA against oxidative assault. Conclusions Thus, present study provides an evidence for the strong anti-oxidant property of Pterostilbene, methoxylated analog of Resveratrol, thereby potentiating its role as an anti-oxidant. PMID:24070177

Walking the Oxidative Stress Tightrope: A Perspective from the Naked Mole-Rat, the Longest-Living Rodent

PubMed Central

Rodriguez, Karl A.; Wywial, Ewa; Perez, Viviana I.; Lambert, Adrian J.; Edrey, Yael H.; Lewis, Kaitlyn N.; Grimes, Kelly; Lindsey, Merry L.; Brand, Martin D.; Buffenstein, Rochelle

2014-01-01

Reactive oxygen species (ROS), by-products of aerobic metabolism, cause oxidative damage to cells and tissue and not surprisingly many theories have arisen to link ROS-induced oxidative stress to aging and health. While studies clearly link ROS to a plethora of divergent diseases, their role in aging is still debatable. Genetic knock-down manipulations of antioxidants alter the levels of accrued oxidative damage, however, the resultant effect of increased oxidative stress on lifespan are equivocal. Similarly the impact of elevating antioxidant levels through transgenic manipulations yield inconsistent effects on longevity. Furthermore, comparative data from a wide range of endotherms with disparate longevity remain inconclusive. Many long-living species such as birds, bats and mole-rats exhibit high-levels of oxidative damage, evident already at young ages. Clearly, neither the amount of ROS per se nor the sensitivity in neutralizing ROS are as important as whether or not the accrued oxidative stress leads to oxidative-damage-linked age-associated diseases. In this review we examine the literature on ROS, its relation to disease and the lessons gleaned from a comparative approach based upon species with widely divergent responses. We specifically focus on the longest lived rodent, the naked mole-rat, which maintains good health and provides novel insights into the paradox of maintaining both an extended healthspan and lifespan despite high oxidative stress from a young age. PMID:21736541

Mechanisms of carbon nanotube-induced toxicity: Focus on oxidative stress

PubMed Central

Shvedova, Anna A.; Pietroiusti, Antonio; Fadeel, Bengt; Kagan, Valerian E.

2015-01-01

Nanotechnologies are emerging as highly promising technologies in many sectors in the society. However, the increasing use of engineered nanomaterials also raises concerns about inadvertent exposure to these materials and the potential for adverse effects on human health and the environment. Despite several years of intensive investigations, a common paradigm for the understanding of nanoparticle-induced toxicity remains to be firmly established. Here, the so-called oxidative stress paradigm is scrutinized. Does oxidative stress represent a secondary event resulting inevitably from disruption of biochemical processes and the demise of the cell, or a specific, non-random event that plays a role in the induction of cellular damage e.g. apoptosis? The answer to this question will have important ramifications for the development of strategies for mitigation of adverse effects of nanoparticles. Recent examples of global lipidomics studies of nanoparticle-induced tissue damage are discussed along with proteomics and transcriptomics approaches to achieve a comprehensive understanding of the complex and interrelated molecular changes in cells and tissues exposed to nanoparticles. We also discuss instances of non-oxidative stress-mediated cellular damage resulting from direct physical interference of nanomaterials with cellular structures. PMID:22513272

Spirulina improves antioxidant status by reducing oxidative stress in rabbits fed a high-cholesterol diet.

PubMed

Kim, Mi Yeon; Cheong, Sun Hee; Lee, Jeung Hee; Kim, Min Ji; Sok, Dai-Eun; Kim, Mee Ree

2010-04-01

The beneficial effect of Spirulina (Spirulina platensis) on tissue lipid peroxidation and oxidative DNA damage was tested in the hypercholesterolemic New Zealand White rabbit model. After hypercholesterolemia was induced by feeding a high cholesterol (0.5%) diet (HCD) for 4 weeks, then HCD supplemented with 1% or 5% Spirulina (SP1 or SP5, respectively) was provided for an additional 8 weeks. Spirulina supplementation significantly reduced the increased lipid peroxidation level in HCD-fed rabbits, and levels recovered to control values. Oxidative stress biomarkers such as glutathione, glutathione peroxidase, glutathione reductase, and glutathione S-transferase were significantly improved in the liver and red blood cells of rabbits fed SP1. Furthermore, SP5 induced antioxidant enzyme activity by 3.1-fold for glutathione, 2.5-fold for glutathione peroxidase, 2.7-fold for glutathione reductase, and 2.3-fold for glutathione S-transferase in liver, compared to the HCD group. DNA damage in lymphocytes was significantly reduced in both the SP1 and SP5 groups, based on the comet assay. Findings from the present study suggest that dietary supplementation with Spirulina may be useful to protect the cells from lipid peroxidation and oxidative DNA damage.

Neuroprotective effect of curcumin against oxidative damage in BV-2 microglia and high intraocular pressure animal model.

PubMed

Yue, Yan-Kun; Mo, Bin; Zhao, Jun; Yu, Ya-Jie; Liu, Lu; Yue, Chang-Li; Liu, Wu

2014-10-01

The involvement of local and systemic oxidative stress in intraocular pressure (IOP) elevation and optic nerve damage has been hypothesized in the pathogenesis of glaucoma. In this study, we aim to evaluate the antioxidant effects of curcumin in BV-2 microglia oxidative damage and assess its neuroprotective effects in a chronic high IOP rat model. BV-2 microglia cell line was used in an in vitro study and Wistar rats were used in an in vivo study. Cultured BV-2 microglia cells were pretreated with 10, 1, or 0.1 μM curcumin for 1 h, and sustained oxidative stress was induced by subjecting BV-2 microglia to 200 μM hydrogen peroxide (H2O2) for 24 h. MTT assay was used to determine cell viability. Changes of intracellular reactive oxygen species (ROS) and apoptosis were analyzed by flow cytometry. Three episcleral veins were cauterized to induce high IOP in Wistar rats and measured by Tonopen. After 6 weeks of treatment with curcumin (10 mg/kg/day) by intragastric administration, surviving of retinal ganglion cells was quantified. Activation of caspase 3, cytochrome c, BAX, and BCL2 was quantified by Western blotting both in BV-2 microglia and in animal model. Data were analyzed with the GraphPad Prism 5.0 software, and P<0.05 was considered to be statistically significant. The in vitro study showed that when BV-2 microglia was pretreated with curcumin, the cell viability increased and the intracellular ROS and apoptosis significantly decreased. In the in vivo study, chronic mild IOP elevation was induced for 4 weeks. In the curcumin-treated group, curcumin protected rat BV-2 microglia from death significantly. In both H2O2-treated BV-2 microglia and glaucoma models, caspase 3, cytochrome c, and BAX were downregulated and BCL2 was upregulated in the curcumin-treated group. Curcumin affords neuroprotective effects by inhibiting oxidative damage and could be a new or adjunctive treatment for glaucoma.

E-cigarettes and flavorings induce inflammatory and pro-senescence responses in oral epithelial cells and periodontal fibroblasts.

PubMed

Sundar, Isaac K; Javed, Fawad; Romanos, Georgios E; Rahman, Irfan

2016-11-22

Electronic-cigarettes (e-cigs) represent a significant and increasing proportion of tobacco product consumption, which may pose an oral health concern. Oxidative/carbonyl stress via protein carbonylation is an important factor in causing inflammation and DNA damage. This results in stress-induced premature senescence (a state of irreversible growth arrest which re-enforces chronic inflammation) in gingival epithelium, which may contribute to the pathogenesis of oral diseases. We show that e-cigs with flavorings cause increased oxidative/carbonyl stress and inflammatory cytokine release in human periodontal ligament fibroblasts, Human Gingival Epithelium Progenitors pooled (HGEPp), and epigingival 3D epithelium. We further show increased levels of prostaglandin-E2 and cycloxygenase-2 are associated with upregulation of the receptor for advanced glycation end products (RAGE) by e-cig exposure-mediated carbonyl stress in gingival epithelium/tissue. Further, e-cigs cause increased oxidative/carbonyl and inflammatory responses, and DNA damage along with histone deacetylase 2 (HDAC2) reduction via RAGE-dependent mechanisms in gingival epithelium. A greater response is elicited by flavored e-cigs. Increased oxidative stress, pro-inflammatory and pro-senescence responses (DNA damage and HDAC2 reduction) can result in dysregulated repair due to proinflammatory and pro-senescence responses in periodontal cells. These data highlight the pathologic role of e-cig aerosol and its flavoring to cells and tissues of the oral cavity in compromised oral health.

Determinants of spontaneous mutation in the bacterium Escherichia coli as revealed by whole-genome sequencing

PubMed Central

Foster, Patricia L.; Lee, Heewook; Popodi, Ellen; Townes, Jesse P.; Tang, Haixu

2015-01-01

A complete understanding of evolutionary processes requires that factors determining spontaneous mutation rates and spectra be identified and characterized. Using mutation accumulation followed by whole-genome sequencing, we found that the mutation rates of three widely diverged commensal Escherichia coli strains differ only by about 50%, suggesting that a rate of 1–2 × 10−3 mutations per generation per genome is common for this bacterium. Four major forces are postulated to contribute to spontaneous mutations: intrinsic DNA polymerase errors, endogenously induced DNA damage, DNA damage caused by exogenous agents, and the activities of error-prone polymerases. To determine the relative importance of these factors, we studied 11 strains, each defective for a major DNA repair pathway. The striking result was that only loss of the ability to prevent or repair oxidative DNA damage significantly impacted mutation rates or spectra. These results suggest that, with the exception of oxidative damage, endogenously induced DNA damage does not perturb the overall accuracy of DNA replication in normally growing cells and that repair pathways may exist primarily to defend against exogenously induced DNA damage. The thousands of mutations caused by oxidative damage recovered across the entire genome revealed strong local-sequence biases of these mutations. Specifically, we found that the identity of the 3′ base can affect the mutability of a purine by oxidative damage by as much as eightfold. PMID:26460006

[6]-Shogaol, a dietary phenolic compound, induces oxidative stress mediated mitochondrial dependant apoptosis through activation of proapoptotic factors in Hep-2 cells.

PubMed

Annamalai, Govindhan; Kathiresan, Suresh; Kannappan, Nagappan

2016-08-01

Ginger (Zingiber officinale) is a well-known herb used in ethnomedicine. [6]-shogaol, a phenolic nature is a major constituent of ginger. In this study, we investigated the anticancer activity of [6]-shogaol in Laryngeal cancer (Hep-2) cells. We demonstrated the effects of [6]-shogaol on the cell growth and apoptosis in Hep-2 cells were analyzed by the generation of reactive oxygen species (ROS), the level of mitochondrial membrane potential (ΔYm), DNA damage and apoptotic morphological changes were analyzed by AO/EtBr, AO and Hoechst staining. Further, apoptotic protein expressions were analyzed by western blot analysis. Our results indicated that [6]-shogaol induces apoptosis as evidenced by loss of cell viability, enhanced ROS, lipid peroxidation results in altered mitochondrial membrane potential, increased DNA damage in Hep-2 cells. Further, the prooxidant role of [6]-shogaol inhibit Bcl-2 expression with the simultaneous up-regulation of Bax, Cytochrome c, Caspase-9 and -3 protein expressions were observed in Hep-2 cells. Thus, [6]-shogaol induces apoptosis in Hep-2 cells through inducing oxidative damage and modulate apoptotic marker expressions. Therefore, [6]-shogaol might be used as a therapeutic agent for the treatment of laryngeal cancer. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Electrochemically Reduced Water Protects Neural Cells from Oxidative Damage

PubMed Central

Hamasaki, Takeki; Kinjo, Tomoya; Nakamichi, Noboru; Teruya, Kiichiro; Kabayama, Shigeru

2014-01-01

Aging-related neurodegenerative disorders are closely associated with mitochondrial dysfunction and oxidative stresses and their incidence tends to increase with aging. Brain is the most vulnerable to reactive species generated by a higher rate of oxygen consumption and glucose utilization compared to other organs. Electrochemically reduced water (ERW) was demonstrated to scavenge reactive oxygen species (ROS) in several cell types. In the present study, the protective effect of ERW against hydrogen peroxide (H2O2) and nitric oxide (NO) was investigated in several rodent neuronal cell lines and primary cells. ERW was found to significantly suppress H2O2 (50–200 μM) induced PC12 and SFME cell deaths. ERW scavenged intracellular ROS and exhibited a protective effect against neuronal network damage caused by 200 μM H2O2 in N1E-115 cells. ERW significantly suppressed NO-induced cytotoxicity in PC12 cells despite the fact that it did not have the ability to scavenge intracellular NO. ERW significantly suppressed both glutamate induced Ca2+ influx and the resulting cytotoxicity in primary cells. These results collectively demonstrated for the first time that ERW protects several types of neuronal cells by scavenging ROS because of the presence of hydrogen and platinum nanoparticles dissolved in ERW. PMID:25383141

DNA oxidative damage and life expectancy in houseflies.

PubMed Central

Agarwal, S; Sohal, R S

1994-01-01

The objective of this study was to explore the relationship between oxidative molecular damage and the aging process by determining whether such damage is associated with the rate of aging, using the adult housefly as the experimental organism. Because the somatic tissues in the housefly consist of long-lived postmitotic cells, it provides an excellent model system for studying cumulative age-related cellular alterations. Rate of aging in the housefly was manipulated by varying the rate of metabolism (physical activity). The concentration of 8-hydroxydeoxyguanosine (80HdG) was used as an indicator of DNA oxidation. Exposure of live flies to x-rays and hyperoxia elevated the level of 8OHdG. The level of 8OHdG in mitochondrial as well as total DNA increased with the age of flies. Mitochondrial DNA was 3 times more susceptible to age-related oxidative damage than nuclear DNA. A decrease in the level of physical activity of the flies was found to prolong the life-span and corresponding reduce the level of 8OHdG in both mitochondrial and total DNA. Under all conditions examined, mitochondrial DNA exhibited a higher level of oxidative damage than total DNA. The 8OHdG levels were found to be inversely associated with the life expectancy of houseflies. The pattern of age-associated accrural of 8OHdG was virtually identical to that of protein carbonyl content. Altoghether, results of this study support the hypothesis that oxidative molecular damage is a causal factor in senescence. PMID:7991627

Roles of oxidative stress in synchrotron radiation X-ray-induced testicular damage of rodents

PubMed Central

Ma, Yingxin; Nie, Hui; Sheng, Caibin; Chen, Heyu; Wang, Ban; Liu, Tengyuan; Shao, Jiaxiang; He, Xin; Zhang, Tingting; Zheng, Chaobo; Xia, Weiliang; Ying, Weihai

2012-01-01

Synchrotron radiation (SR) X-ray has characteristic properties such as coherence and high photon flux, which has excellent potential for its applications in medical imaging and cancer treatment. However, there is little information regarding the mechanisms underlying the damaging effects of SR X-ray on biological tissues. Oxidative stress plays an important role in the tissue damage induced by conventional X-ray, while the role of oxidative stress in the tissue injury induced by SR X-ray remains unknown. In this study we used the male gonads of rats as a model to study the roles of oxidative stress in SR X-ray-induced tissue damage. Exposures of the testes to SR X-ray at various radiation doses did not significantly increase the lipid peroxidation of the tissues, assessed at one day after the irradiation. No significant decreases in the levels of GSH or total antioxidation capacity were found in the SR X-ray-irradiated testes. However, the SR X-ray at 40 Gy induced a marked increase in phosphorylated H2AX – a marker of double-strand DNA damage, which was significantly decreased by the antioxidant N-acetyl cysteine (NAC). NAC also attenuated the SR X-ray-induced decreases in the cell layer number of seminiferous tubules. Collectively, our observations have provided the first characterization of SR X-ray-induced oxidative damage of biological tissues: SR X-ray at high doses can induce DNA damage and certain tissue damage during the acute phase of the irradiation, at least partially by generating oxidative stress. However, SR X-ray of various radiation doses did not increase lipid peroxidation. PMID:22837810

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

PubMed

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.

Muscarinic Receptor Activation Protects Cells from Apoptotic Effects of DNA Damage, Oxidative Stress, and Mitochondrial Inhibition*

PubMed Central

De Sarno, Patrizia; Shestopal, Svetlana A.; King, Taj D.; Zmijewska, Anna; Song, Ling; Jope, Richard S.

2006-01-01

The impact of muscarinic receptor stimulation was examined on apoptotic signaling induced by DNA damage, oxidative stress, and mitochondrial impairment. Exposure of human neuroblastoma SH-SY5Y cells to the DNA-damaging agent camptothecin increased p53 levels, activated caspase-3, and caused cell death. Pretreatment with oxotremorine-M, a selective agonist of muscarinic receptors that are expressed endogenously in these cells, did not affect the accumulation of p53 but greatly attenuated caspase-3 activation and protected from cell death to nearly the same extent as treatment with a general caspase inhibitor. Treatment with 50–200 μm H2O2 caused the activation of caspase-3 beginning after 2–3 h, followed by eventual cell death. Oxotremorine-M pretreatment protected cells from H2O2-inducedcaspase-3 activation and death, and this was equivalent to protection afforded by a caspase inhibitor. Muscarinic receptor stimulation also protected cells from caspase-3 activation induced by exposure to rotenone, a mitochondrial complex 1 inhibitor, but no protection was evident from staurosporine-induced caspase-3 activation. The mechanism of protection afforded by muscarinic receptor activation from camptothecin-induced apoptotic signaling involved blockade of mitochondrial cytochrome c release associated with a bolstering of mitochondrial bcl-2 levels and blockade of the translocation of Bax to mitochondria. Likely the most proximal of these events to muscarinic receptor activation, mitochondrial Bax accumulation, also was attenuated by oxotremorine-M treatment after treatment with H2O2 or rotenone. These results demonstrate that stimulation of muscarinic receptors provides substantial protection from DNA damage, oxidative stress, and mitochondrial impairment, insults that may be encountered by neurons in development, aging, or neurodegenerative diseases. These findings suggest that neurotransmitter-induced signaling bolsters survival mechanisms, and inadequate neurotransmission may exacerbate neuronal loss. PMID:12538580

Hydrogen-Rich Water Ameliorates Total Body Irradiation-Induced Hematopoietic Stem Cell Injury by Reducing Hydroxyl Radical

PubMed Central

Xue, Xiaolei; Han, Xiaodan; Li, Yuan; Lu, Lu; Li, Deguan

2017-01-01

We examined whether consumption of hydrogen-rich water (HW) could ameliorate hematopoietic stem cell (HSC) injury in mice with total body irradiation (TBI). The results indicated that HW alleviated TBI-induced HSC injury with respect to cell number alteration and to the self-renewal and differentiation of HSCs. HW specifically decreased hydroxyl radical (∙OH) levels in the c-kit+ cells of 4 Gy irradiated mice. Proliferative bone marrow cells (BMCs) increased and apoptotic c-kit+ cells decreased in irradiated mice uptaken with HW. In addition, the mean fluorescence intensity (MFI) of γ-H2AX and percentage of 8-oxoguanine positive cells significantly decreased in HW-treated c-kit+ cells, indicating that HW can alleviate TBI-induced DNA damage and oxidative DNA damage in c-kit+ cells. Finally, the cell cycle (P21), cell apoptosis (BCL-XL and BAK), and oxidative stress (NRF2, HO-1, NQO1, SOD, and GPX1) proteins were significantly altered by HW in irradiated mouse c-kit+ cells. Collectively, the present results suggest that HW protects against TBI-induced HSC injury. PMID:28243358

Hydrogen-Rich Water Ameliorates Total Body Irradiation-Induced Hematopoietic Stem Cell Injury by Reducing Hydroxyl Radical.

PubMed

Zhang, Junling; Xue, Xiaolei; Han, Xiaodan; Li, Yuan; Lu, Lu; Li, Deguan; Fan, Saijun

2017-01-01

We examined whether consumption of hydrogen-rich water (HW) could ameliorate hematopoietic stem cell (HSC) injury in mice with total body irradiation (TBI). The results indicated that HW alleviated TBI-induced HSC injury with respect to cell number alteration and to the self-renewal and differentiation of HSCs. HW specifically decreased hydroxyl radical ( ∙ OH) levels in the c-kit + cells of 4 Gy irradiated mice. Proliferative bone marrow cells (BMCs) increased and apoptotic c-kit + cells decreased in irradiated mice uptaken with HW. In addition, the mean fluorescence intensity (MFI) of γ -H2AX and percentage of 8-oxoguanine positive cells significantly decreased in HW-treated c-kit + cells, indicating that HW can alleviate TBI-induced DNA damage and oxidative DNA damage in c-kit + cells. Finally, the cell cycle (P21), cell apoptosis (BCL-XL and BAK), and oxidative stress (NRF2, HO-1, NQO1, SOD, and GPX1) proteins were significantly altered by HW in irradiated mouse c-kit + cells. Collectively, the present results suggest that HW protects against TBI-induced HSC injury.

Evaluation of cell wall damage by dimethyl sulfoxide in Candida species.

PubMed

León-García, María Cristina; Ríos-Castro, Emmanuel; López-Romero, Everardo; Cuéllar-Cruz, Mayra

2017-10-01

Studies dealing with the response of microorganisms to oxidative stress require the dissolution of oxidant agents in an appropriate solvent. A commonly used medium is dimethyl sulfoxide, which has been considered as an innocuous polar solvent. However, we have observed significant differences between control, untreated cells and those receiving increasing amounts of the oxidant and hence increasing amounts of DMSO, to the maximum allowed of 1%. Here we show that, while this solvent does not influence yeast cell viability, it does affect expression of cell wall proteins as well as catalase activity. Therefore, its use in future studies of oxidative stress as an innocuous solvent should be reconsidered. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Cytotoxicity and DNA cleavage with core-shell nanocomposites functionalized by a KH domain DNA binding peptide

NASA Astrophysics Data System (ADS)

Bazak, Remon; Ressl, Jan; Raha, Sumita; Doty, Caroline; Liu, William; Wanzer, Beau; Salam, Seddik Abdel; Elwany, Samy; Paunesku, Tatjana; Woloschak, Gayle E.

2013-11-01

A nanoconjugate was composed of metal oxide nanoparticles decorated with peptides and fluorescent dye and tested for DNA cleavage following UV light activation. The peptide design was based on a DNA binding domain, the so called KH domain of the hnRNPK protein. This ``KH peptide'' enabled cellular uptake of nanoconjugates and their entry into cell nuclei. The control nanoconjugate carried no peptide; it consisted only of the metal oxide nanoparticle prepared as Fe3O4@TiO2 nanocomposite and the fluorescent dye alizarin red S. These components of either construct are responsible for nanoconjugate activation by UV light and the resultant production of reactive oxygen species (ROS). Production of ROS at different subcellular locations causes damage to different components of cells: only nanoconjugates inside cell nuclei can be expected to cause DNA cleavage. Degradation of cellular DNA with KH peptide decorated nanoconjugates exceeded the DNA damage obtained from control, no-peptide nanoconjugate counterparts. Moreover, caspase activation and cell death were more extensive in the same cells.A nanoconjugate was composed of metal oxide nanoparticles decorated with peptides and fluorescent dye and tested for DNA cleavage following UV light activation. The peptide design was based on a DNA binding domain, the so called KH domain of the hnRNPK protein. This ``KH peptide'' enabled cellular uptake of nanoconjugates and their entry into cell nuclei. The control nanoconjugate carried no peptide; it consisted only of the metal oxide nanoparticle prepared as Fe3O4@TiO2 nanocomposite and the fluorescent dye alizarin red S. These components of either construct are responsible for nanoconjugate activation by UV light and the resultant production of reactive oxygen species (ROS). Production of ROS at different subcellular locations causes damage to different components of cells: only nanoconjugates inside cell nuclei can be expected to cause DNA cleavage. Degradation of cellular DNA with KH peptide decorated nanoconjugates exceeded the DNA damage obtained from control, no-peptide nanoconjugate counterparts. Moreover, caspase activation and cell death were more extensive in the same cells. Electronic supplementary information (ESI) available: http://janus.northwestern.edu/wololab/auxiliary/supplementary_data_2013.docx. See DOI: 10.1039/c3nr02203j

Damage to Aspergillus fumigatus and Rhizopus oryzae Hyphae by Oxidative and Nonoxidative Microbicidal Products of Human Neutrophils In Vitro

PubMed Central

Diamond, Richard D.; Clark, Robert A.

1982-01-01

Our previous studies established that human neutrophils could damage and probably kill hyphae of Aspergillus fumigatus and Rhizopus oryzae in vitro, primarily by oxygen-dependent mechanisms active at the cell surface. These studies were extended, again quantitating hyphal damage by reduction in uptake of 14C-labeled uracil or glutamine. Neither A. fumigatus nor R. oryzae hyphae were damaged by neutrophils from patients with chronic granulomatous disease, confirming the importance of oxidative mechanisms in damage to hyphae. In contrast, neutrophils from one patient with hereditary myeloperoxidase deficiency damaged R. oryzae but not A. fumigatus hyphae. Cell-free, in vitro systems were then used to help determine the relative importance of several potentially fungicidal products of neutrophils. Both A. fumigatus and R. oryzae hyphae were damaged by the myeloperoxidase-hydrogen peroxide-halide system either with reagent hydrogen peroxide or enzymatic systems for generating hydrogen peroxide (glucose oxidase with glucose, or xanthine oxidase with either hypoxanthine or acetaldehyde). Iodide with or without chloride supported the reaction, but damage was less with chloride alone as the halide cofactor. Hydrogen peroxide alone damaged hyphae only in concentrations ≥1 mM, but 0.01 mM hypochlorous acid, a potential product of the myeloperoxidase system, significantly damaged R. oryzae hyphae (a 1 mM concentration was required for significant damage to A. fumigatus hyphae). Damage to hyphae by the myeloperoxidase system was inhibited by azide, cyanide, catalase, histidine, and tryptophan, but not by superoxide dismutase, dimethyl sulfoxide, or mannitol. Photoactivation of the dye rose bengal resulted in hyphal damage which was inhibited by histidine, tryptophan, and 1,4-diazobicyclo(2,2,2)octane. Lysates of neutrophils or separated neutrophil granules did not affect A. fumigatus hyphae, but did damage R. oryzae hyphae. Similarly, three preparations of cationic proteins purified from human neutrophil granules were more active in damaging R. oryzae than A. fumigatus hyphae. This damage, as with the separated granules and whole cell lysates, was inhibited by the polyanion heparin. Damage to R. oryzae hyphae by neutrophil cationic proteins was enhanced by activity of the complete myeloperoxidase system or by hydrogen peroxide alone in subinhibitory concentrations. These data support the importance of oxidative products in general and the myeloperoxidase system in particular in damage to hyphae by neutrophils. Cationic proteins may also contribute significantly to neutrophil-mediated damage to R. oryzae hyphae. PMID:6292103

Mitochondria as Sub-cellular Targets of Space Radiation

NASA Astrophysics Data System (ADS)

Hei, Tom; Zhang, Bo; Davidson, Mercy

High linear energy transfer (LET) radiation including alpha particles and heavy ions is the major type of radiation find in space and is considered a potential health risk for astronauts. Even though the chance that these high LET particles traversing through the cytoplasm of cells is higher than that through the nuclei, the contribution of targeted cytoplasmic irradiation, to the induction of genomic instability and other chromosomal damages induced by high LET radiation is not known. Mitochondria are the sole energy center of a cell and normal mitochondria are highly dynamic organelles that move along microtubules or microfilaments and continuously fuse and divide in healthy cells. A balance between mitochondrial fusion and fission is essential to maintain normal mitochondrial function. Targeted cytoplasmic irradiation by high LET alpha particles induced DNA oxidative damage and double strand breaks in wild type rho+ human small airway epithelial (SAE) cells. Furthermore, there was a significant increase in autophagy and micronuclei, which is an indication of genomic instability, together with the activation of nuclear factor kappa-B (NF-kappaB) and mitochondrial inducible nitric oxide synthase (iNOS) signaling pathways in rho+ SAE cells. In contrast, SAE cells with depleted mitochondrial DNA (rho0) and, therefore, no oxidative metabolic functions, exhibited a significantly lower response to these same endpoints examined after cytoplasmic irradiation with high LET alpha particles. The results indicate that normal mitochondrial function is essential in mediating radiation induced genotoxic damages in mammalian cells. Furthermore, the findings may shed some light in the design of countermeasures for space radiation protection.

Generation of reactive oxygen species and oxidative stress in Escherichia coli and Staphylococcus aureus by a novel semiconductor catalyst

NASA Astrophysics Data System (ADS)

Chow, K. L.; Mak, N. K.; Wong, M. H.; Zhou, X. F.; Liang, Y.

2011-03-01

The objective of this study was to investigate antimicrobial mechanisms of a new catalytic material (charge transfer auto oxidation-reduction type catalyst, CT catalyst) that may have great potential for application in water/wastewater treatment. Generation of reactive oxygen species (ROS) in bacteria-free solution, induction of ROS and oxidative damage in bacteria (including E. coli and S. aureus) were examined for the CT catalyst. The results showed that significantly higher ( p < 0.05, via t-test) amount of hydroxyl radicals was generated by the CT catalyst compared with the control, particularly after 6 h of contact time that more than twice of the amount of the control was produced. The generation of ROS in the bacteria was greater under higher pH and temperature levels, which closely related with the oxidative damage in cells. The results indicated that CT catalyst induced oxidative damage in the bacteria might serve as an important mechanism interpreting the anti-microbial function of the CT catalyst.

Genoprotective effect of hyaluronic acid against benzalkonium chloride-induced DNA damage in human corneal epithelial cells

PubMed Central

Wu, Han; Zhang, Huina; Wang, Changjun; Wu, Yihua; Xie, Jiajun; Jin, Xiuming; Yang, Jun

2011-01-01

Purpose The aim of this study was to investigate hyaluronic acid (HA) protection on cultured human corneal epithelial cells (HCEs) against benzalkonium chloride (BAC)-induced DNA damage and intracellular reactive oxygen species (ROS) increase. Methods Cells were incubated with different concentrations of BAC with or without the presence of 0.2% HA for 30 min. DNA damage to HCEs was examined by alkaline comet assay and by immunofluorescence microscopic detection of the phosphorylated form of histone variant H2AX (γH2AX) foci. ROS production was assessed by the fluorescent probe, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Cell apoptosis was determined with annexin V staining by flow cytometry. Results HA significantly reduced BAC-induced DNA damage as indicated by the tail length (TL) and tail moment (TM) of alkaline comet assay and by γH2AX foci formation, respectively. Moreover, HA significantly decreased BAC-induced ROS increase and cell apoptosis. However, exposure to HA alone did not produce any significant change in DNA damage, ROS generation, or cell apoptosis. Conclusions BAC could induce DNA damage and cell apoptosis in HCEs, probably through increasing oxidative stress. Furthermore, HA was an effective protective agent that had antioxidant properties and could decrease DNA damage and cell apoptosis induced by BAC. PMID:22219631

Ferulic acid (FA) abrogates γ-radiation induced oxidative stress and DNA damage by up-regulating nuclear translocation of Nrf2 and activation of NHEJ pathway.

PubMed

Das, Ujjal; Manna, Krishnendu; Khan, Amitava; Sinha, Mahuya; Biswas, Sushobhan; Sengupta, Aaveri; Chakraborty, Anindita; Dey, Sanjit

2017-01-01

The present study was aimed to evaluate the radioprotective effect of ferulic acid (FA), a naturally occurring plant flavonoid in terms of DNA damage and damage related alterations of repair pathways by gamma radiation. FA was administered at a dose of 50 mg/kg body weight for five consecutive days prior to exposing the swiss albino mice to a single dose of 10 Gy gamma radiation. Ionising radiation induces oxidative damage manifested by decreased expression of Cu, Zn-SOD (SOD stands for super oxide dismutase), Mn-SOD and catalase. Gamma radiation promulgated reactive oxygen species (ROS) mediated DNA damage and modified repair pathways. ROS enhanced nuclear translocation of p53, activated ATM (ataxia telangiectasia-mutated protein), increased expression of GADD45a (growth arrest and DNA-damage-inducible protein) gene and inactivated Non homologous end joining (NHEJ) repair pathway. The comet formation in irradiated mice peripheral blood mononuclear cells (PBMC) reiterated the DNA damage in IR exposed groups. FA pretreatment significantly prevented the comet formation and regulated the nuclear translocation of p53, inhibited ATM activation and expression of GADD45a gene. FA promoted the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and activated NHEJ repair pathway to overcome ROS mediated oxidative stress and DNA damage. Therefore, the current study stated that FA can challenge the oxidative stress by (i) inducing nuclear translocation of Nrf2, (ii) scavenging ROS, and (iii) activating NHEJ DNA repair process.

Mono-2-ethylhexyl phthalate induces oxidative stress responses in human placental cells in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tetz, Lauren M., E-mail: ltetz@umich.edu; Cheng, Adrienne A.; Korte, Cassandra S.

Di-2-ethylhexyl phthalate (DEHP) is an environmental contaminant commonly used as a plasticizer in polyvinyl chloride products. Exposure to DEHP has been linked to adverse pregnancy outcomes in humans including preterm birth, low birth-weight, and pregnancy loss. Although oxidative stress is linked to the pathology of adverse pregnancy outcomes, effects of DEHP metabolites, including the active metabolite, mono-2-ethylhexyl phthalate (MEHP), on oxidative stress responses in placental cells have not been previously evaluated. The objective of the current study is to identify MEHP-stimulated oxidative stress responses in human placental cells. We treated a human placental cell line, HTR-8/SVneo, with MEHP and thenmore » measured reactive oxygen species (ROS) generation using the dichlorofluorescein assay, oxidized thymine with mass-spectrometry, redox-sensitive gene expression with qRT-PCR, and apoptosis using a luminescence assay for caspase 3/7 activity. Treatment of HTR-8 cells with 180 μM MEHP increased ROS generation, oxidative DNA damage, and caspase 3/7 activity, and resulted in differential expression of redox-sensitive genes. Notably, 90 and 180 μM MEHP significantly induced mRNA expression of prostaglandin-endoperoxide synthase 2 (PTGS2), an enzyme important for synthesis of prostaglandins implicated in initiation of labor. The results from the present study are the first to demonstrate that MEHP stimulates oxidative stress responses in placental cells. Furthermore, the MEHP concentrations used were within an order of magnitude of the highest concentrations measured previously in human umbilical cord or maternal serum. The findings from the current study warrant future mechanistic studies of oxidative stress, apoptosis, and prostaglandins as molecular mediators of DEHP/MEHP-associated adverse pregnancy outcomes. - Highlights: ► MEHP increased reactive oxygen species, oxidative DNA damage, and caspase activity. ► MEHP induced expression of PTGS2, a gene important in pregnancy and parturition ► MEHP treatment resulted in differential expression of GLRX2, TXNRD1, and DHCR24.« less

Effects of flight activity and age on oxidative damage in the honey bee, Apis mellifera.

PubMed

Margotta, Joseph W; Roberts, Stephen P; Elekonich, Michelle M

2018-05-03

Frequent and highly aerobic behaviors likely contribute to naturally occurring stress, accelerate senescence, and limit lifespan. To understand how the physiological and cellular mechanisms that determine the onset and duration of senescence are shaped by behavioral development and behavioral duration, we exploited the tractability of the honey bee ( Apis mellifera ) model system. First, we determined if a cause-effect relationship exists between honey bee flight and oxidative stress by comparing oxidative damage accrued from intense flight bouts to damage accrued from D-galactose ingestion, which induces oxidative stress and limit lifespan in other insects. Second, we experimentally manipulated the duration of honey bee flight across a range of ages to determine their effects on reactive oxygen species (ROS) accumulation and associated enzymatic antioxidant protective mechanisms. In bees fed D-galactose, lipid peroxidation (MDA) was higher than in bees fed sucrose and age-matched bees with high and low flight experience collected from a colony. Bees with high amounts of flight experience exhibited elevated 8-OHdG, a marker of oxidative DNA damage, relative to bees with less flight experience. Bees with high amounts of flight experience also showed increased levels of pro-oxidants (superoxide and H 2 O 2 ) and decreased or unchanged levels of antioxidants (SOD and catalase). These data implicate an imbalance of pro- to antioxidants in flight-associated oxidative stress and reveal how behavior can damage a cell and consequently limit lifespan. © 2018. Published by The Company of Biologists Ltd.

Possible mechanisms for delayed neurological damage in lightning and electrical injury.

PubMed

Reisner, Andrew D

2013-01-01

This article provides and reviews hypotheses to help explain the poorly understood phenomenon of delayed neurological injury following lightning or electrical injury. A review of extant literature provides a starting point to integrate what is already known in an attempt to provide new hypotheses for this phenomenon, as well as to discuss existing hypotheses. The author proposes two theories which stem from the literature on the damaging effects of oxidative stress, and also reviews an existing hypothesis, the electroporation hypothesis. The former two theories can account for delayed damage which is either of vascular or nonvascular origin. The electroporation hypothesis can explain changes both in cases where there is cellular loss as well as cases where there only appears to be change in function after lightning or electrical injury. Although all theories discussed are speculative, the formation of hypotheses is always a starting point in the scientific process. In cases where there is delayed neurological damage with a vascular origin, it is possible that free radicals resulting from oxidative stress may gradually damage spinal vascular endothelial cells, cutting off blood supply, and ending in death of spinal neurons. When the delayed condition is demyelination without vascular damage, it is possible that the free radicals from oxidative stress are formed directly from the lipids found in abundance in myelin cells. The electroporation hypothesis, the formation of additional pores in neurons, may best explain immediate or progressive changes in structure and function after lightning or electrical injury.

Protective effects of the compounds isolated from the seed of Psoralea corylifolia on oxidative stress-induced retinal damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Kyung-A; Shim, Sang Hee; Ahn, Hong Ryul

2013-06-01

The mechanism underlying glaucoma remains controversial, but apoptosis caused by increased levels of reactive oxygen species (ROS) is thought to play a role in its pathogenesis. We investigated the effects of compounds isolated from Psoralea corylifolia on oxidative stress-induced cell death in vitro and in vivo. Transformed retinal ganglion cells (RGC-5) were treated with L-buthione-(S,R)-sulfoximine (BSO) and glutamate in the presence or with pre-treatment with compound 6, bakuchiol isolated from P. corylifolia. We observed reduced cell death in cells pre-treated with bakuchiol. Moreover, bakuchiol inhibited the oxidative stress-induced decrease of mitochondrial membrane potential (MMP, ΔΨm). Furthermore, while intracellular Ca{sup 2+}more » was high in RGC-5 cells after exposure to oxidative stress, bakuchiol reduced these levels. In an in vivo study, in which rat retinal damage was induced by intravitreal injection of N-methyl-D-aspartate (NMDA), bakuchiol markedly reduced translocation of AIF and release of cytochrome c, and inhibited up-regulation of cleaved caspase-3, cleaved caspase-9, and cleaved PARP. The survival rate of retinal ganglion cells (RGCs) 7 days after optic nerve crush (ONC) in mice was significantly decreased; however, bakuchiol attenuated the loss of RGCs. Moreover, bakuchiol attenuated ONC-induced up-regulation of apoptotic proteins, including cleaved PARP, cleaved caspase-3, and cleaved caspase-9. Bakuchiol also significantly inhibited translocation of mitochondrial AIF into the nuclear fraction and release of mitochondrial cytochrome c into the cytosol. These results demonstrate that bakuchiol isolated from P. corylifolia has protective effects against oxidative stress-induced retinal damage, and may be considered as an agent for treating or preventing retinal degeneration. - Highlights: • Psoralea corylifolia have neuroprotective effects in vitro and in vivo. • Bakuchiol attenuated the increase of apoptotic proteins induced by oxidative stress. • Bakuchiol restored the reduced mitochondrial membrane potential. • Bakuchiol attenuated the increase of intracellular Ca{sup 2+}. • Bakuchiol attenuated retinal degeneration in vivo.« less

Accelerated aging in schizophrenia patients: the potential role of oxidative stress.

PubMed

Okusaga, Olaoluwa O

2014-08-01

Several lines of evidence suggest that schizophrenia, a severe mental illness characterized by delusions, hallucinations and thought disorder is associated with accelerated aging. The free radical (oxidative stress) theory of aging assumes that aging occurs as a result of damage to cell constituents and connective tissues by free radicals arising from oxygen-associated reactions. Schizophrenia has been associated with oxidative stress and chronic inflammation, both of which also appear to reciprocally induce each other in a positive feedback manner. The buildup of damaged macromolecules due to increased oxidative stress and failure of protein repair and maintenance systems is an indicator of aging both at the cellular and organismal level. When compared with age-matched healthy controls, schizophrenia patients have higher levels of markers of oxidative cellular damage such as protein carbonyls, products of lipid peroxidation and DNA hydroxylation. Potential confounders such as antipsychotic medication, smoking, socio-economic status and unhealthy lifestyle make it impossible to solely attribute the earlier onset of aging-related changes or oxidative stress to having a diagnosis of schizophrenia. Regardless of whether oxidative stress can be attributed solely to a diagnosis of schizophrenia or whether it is due to other factors associated with schizophrenia, the available evidence is in support of increased oxidative stress-induced cellular damage of macromolecules which may play a role in the phenomenon of accelerated aging presumed to be associated with schizophrenia.

Chamomile confers protection against hydrogen peroxide-induced toxicity through activation of Nrf2-mediated defense response.

PubMed

Bhaskaran, Natarajan; Srivastava, Janmejai K; Shukla, Sanjeev; Gupta, Sanjay

2013-01-01

Oxidative stress plays an important role in the development of various human diseases. Aqueous chamomile extract is used as herbal medicine, in the form of tea, demonstrated to possess antiinflammatory and antioxidant properties. We demonstrate the cytoprotective effects of chamomile on hydrogen peroxide (H₂O₂)-induced cellular damage in macrophage RAW 264.7 cells. Pretreatment of cells with chamomile markedly attenuated H₂O₂-induced cell viability loss in a dose-dependent manner. The mechanisms by which chamomile-protected macrophages from oxidative stress was through the induction of several antioxidant enzymes including NAD(P)H:quinone oxidoreductase, superoxide dismutase, and catalase and increase nuclear accumulation of the transcription factor Nrf2 and its binding to antioxidant response elements. Furthermore, chamomile dose-dependently reduced H₂O₂-mediated increase in the intracellular levels of reactive oxygen species. Our results, for the first time, demonstrate that chamomile has protective effects against oxidative stress and might be beneficial to provide defense against cellular damage. Copyright © 2012 John Wiley & Sons, Ltd.

Chamomile Confers Protection against Hydrogen Peroxide-Induced Toxicity through Activation of Nrf2-Mediated Defense Response

PubMed Central

Bhaskaran, Natarajan; Srivastava, Janmejai K.; Shukla, Sanjeev; Gupta, Sanjay

2014-01-01

Oxidative stress plays an important role in the development of various human diseases. Aqueous chamomile extract is used as herbal medicine, in the form of tea, demonstrated to possess antiinflammatory and antioxidant properties. We demonstrate the cytoprotective effects of chamomile on hydrogen peroxide (H2O2)-induced cellular damage in macrophage RAW 264.7 cells. Pretreatment of cells with chamomile markedly attenuated H2O2-induced cell viability loss in a dose-dependent manner. The mechanisms by which chamomile-protected macrophages from oxidative stress was through the induction of several antioxidant enzymes including NAD (P)H:quinone oxidoreductase, superoxide dismutase, and catalase and increase nuclear accumulation of the transcription factor Nrf2 and its binding to antioxidant response elements. Furthermore, chamomile dose-dependently reduced H2O2-mediated increase in the intracellular levels of reactive oxygen species. Our results, for the first time, demonstrate that chamomile has protective effects against oxidative stress and might be beneficial to provide defense against cellular damage. PMID:22511316

New arylated benzo[h]quinolines induce anti-cancer activity by oxidative stress-mediated DNA damage.

PubMed

Yadav, Dharmendra K; Rai, Reeta; Kumar, Naresh; Singh, Surjeet; Misra, Sanjeev; Sharma, Praveen; Shaw, Priyanka; Pérez-Sánchez, Horacio; Mancera, Ricardo L; Choi, Eun Ha; Kim, Mi-Hyun; Pratap, Ramendra

2016-12-06

The anti-cancer activity of the benzo[h]quinolines was evaluated on cultured human skin cancer (G361), lung cancer (H460), breast cancer (MCF7) and colon cancer (HCT116) cell lines. The inhibitory effect of these compounds on the cell growth was determined by the MTT assay. The compounds 3e, 3f, 3h and 3j showed potential cytotoxicity against these human cancer cell lines. Effect of active compounds on DNA oxidation and expression of apoptosis related gene was studied. We also developed a quantitative method to measure the activity of cyclin-dependent kinases-2 (CDK2) by western blotting in the presence of active compound. In addition, molecular docking revealed that benzo[h]quinolines can correctly dock into the hydrophobic pocket of the targets receptor protein aromatase and CDK2, while their bioavailability/drug-likeness was predicted to be acceptable but requires future optimization. These findings reveal that benzo[h]quinolines act as anti-cancer agents by inducing oxidative stress-mediated DNA damage.

Early Diagnosis, Treatment, and Care of Cancer Patients

DTIC Science & Technology

2009-09-01

damage caused by cytarabine . (Months 1-24) The toxicity for CNS progenitor cells in vitro revealed in our first year’s work on parthenolide...and the toxicity seen for cytarabine , indicated that it was necessary to examine other relevant chemotherapeutic agents to try and identify a...task #2: Demonstrate that mice in which purified cells are more oxidized in vitro will exhibit more extensive damage from cytarabine , parthenolide (or

Sensorineural hearing loss and ischemic injury: Development of animal models to assess vascular and oxidative effects.

PubMed

Olivetto, E; Simoni, E; Guaran, V; Astolfi, L; Martini, A

2015-09-01

Hearing loss may be genetic, associated with aging or exposure to noise or ototoxic substances. Its aetiology can be attributed to vascular injury, trauma, tumours, infections or autoimmune response. All these factors could be related to alterations in cochlear microcirculation resulting in hypoxia, which in turn may damage cochlear hair cells and neurons, leading to deafness. Hypoxia could underlie the aetiology of deafness, but very few data about it are presently available. The aim of this work is to develop animal models of hypoxia and ischemia suitable for study of cochlear vascular damage, characterizing them by electrophysiology and gene/protein expression analyses. The effects of hypoxia in infarction were mimicked in rat by partial permanent occlusion of the left coronary artery, and those of ischemia in thrombosis by complete temporary carotid occlusion. In our models both hypoxia and ischemia caused a small but significant hearing loss, localized at the cochlear apex. A slight induction of the coagulation cascade and of oxidative stress pathways was detected as cell survival mechanism, and cell damages were found on the cuticular plate of outer hair cells only after carotid ischemia. Based on these data, the two developed models appear suitable for in vivo studies of cochlear vascular damage. Copyright © 2015 Elsevier B.V. All rights reserved.

Redox cycling of Cu(II) by 6-mercaptopurine leads to ROS generation and DNA breakage: possible mechanism of anticancer activity.

PubMed

Rehman, Sayeed Ur; Zubair, Haseeb; Sarwar, Tarique; Husain, Mohammed Amir; Ishqi, Hassan Mubarak; Nehar, Shamshun; Tabish, Mohammad

2015-02-01

6-Mercaptopurine (6MP) is a well-known purine antimetabolite used to treat childhood acute lymphoblastic leukemia and other diseases. Cancer cells as compared to normal cells are under increased oxidative stress and show high copper level. These differences between cancer cells and normal cells can be targeted to develop effective cancer therapy. Pro-oxidant property of 6MP in the presence of metal ions is not well documented. Redox cycling of Cu(II) to Cu(I) was found to be efficiently mediated by 6MP. We have performed a series of in vitro experiments to demonstrate the pro-oxidant property of 6MP in the presence of Cu(II). Studies on human lymphocytes confirmed the DNA damaging ability of 6MP in the presence of Cu(II). Since 6MP possesses DNA damaging ability by producing reactive oxygen species (ROS) in the presence of Cu(II), it may also possess apoptosis-inducing activity by involving endogenous copper ions. Essentially, this would be an alternative and copper-dependent pathway for anticancer activity of 6MP.

Decreased photosynthetic rate under high temperature in wheat is due to lipid desaturation, oxidation, acylation, and damage of organelles.

PubMed

Djanaguiraman, M; Boyle, D L; Welti, R; Jagadish, S V K; Prasad, P V V

2018-04-05

High temperature is a major abiotic stress that limits wheat (Triticum aestivum L.) productivity. Variation in levels of a wide range of lipids, including stress-related molecular species, oxidative damage, cellular organization and ultrastructural changes were analyzed to provide an integrated view of the factors that underlie decreased photosynthetic rate under high temperature stress. Wheat plants of cultivar Chinese Spring were grown at optimum temperatures (25/15 °C, maximum/minimum) until the onset of the booting stage. Thereafter, plants were exposed to high temperature (35/25 °C) for 16 d. Compared with optimum temperature, a lower photosynthetic rate was observed at high temperature which is an interplay between thylakoid membrane damage, thylakoid membrane lipid composition, oxidative damage of cell organelle, and stomatal and non-stomatal limitations. Triacylglycerol levels were higher under high temperature stress. Polar lipid fatty acyl unsaturation was lower at high temperature, while triacylglycerol unsaturation was the same at high temperature and optimum temperature. The changes in lipid species indicates increases in activities of desaturating, oxidizing, glycosylating and acylating enzymes under high temperature stress. Cumulative effect of high temperature stress led to generation of reactive oxygen species, cell organelle and membrane damage, and reduced antioxidant enzyme activity, and imbalance between reactive oxygen species and antioxidant defense system. Taken together with recent findings demonstrating that reactive oxygen species are formed from and are removed by thylakoid lipids, the data suggest that reactive oxygen species production, reactive oxygen species removal, and changes in lipid metabolism contribute to decreased photosynthetic rate under high temperature stress.

Resveratrol protects primary rat hepatocytes against oxidative stress damage: activation of the Nrf2 transcription factor and augmented activities of antioxidant enzymes.

PubMed

Rubiolo, Juan Andrés; Mithieux, Gilles; Vega, Félix Victor

2008-09-04

Oxidative stress is recognized as an important factor in the development of liver pathologies. The reactive oxygen species endogenously generated or as a consequence of xenobiotic metabolism are eliminated by enzymatic and nonenzymatic cellular systems. Besides endogen defences, the antioxidant consumption in the diet has an important role in the protection against the development of diseases product of oxidative damage. Resveratrol is a naturally occurring compound which is part of the human diet. This molecule has been shown to have many biological properties, including antioxidant activity. We decided to test if resveratrol could protect primary hepatocytes in culture from oxidative stress damage and if so, to determine if this compound affects the cellular detoxifying systems and their regulation through the Nrf2 transcription factor that regulates the expression of antioxidant and phase II detoxifying enzymes. Cell death by necrosis was detected by measuring the activity of lactate dehydrogenase liberated to the medium. The activities of antioxidant and phase II enzymes were measured using previously described methods. Activation of the Nrf2 transcription factor was studied by confocal microscopy and the Nrf2 and its coding mRNA levels were determined by western blot and quantitative PCR respectively. Resveratrol pre-treatment effectively protected hepatocytes in culture exposed to oxidative stress, increasing the activities of catalase, superoxide dismutase, glutathione peroxidase, NADPH quinone oxidoreductase and glutathione-S-transferase. Resveratrol increases the level of Nrf2 and induces its translocation to the nucleus. Also, it increases the concentration of the coding mRNA for Nrf2. In this work we show that resveratrol could be a useful drug for the protection of liver cells from oxidative stress induced damage.

Silencing of human DNA polymerase λ causes replication stress and is synthetically lethal with an impaired S phase checkpoint

PubMed Central

Zucca, Elisa; Bertoletti, Federica; Wimmer, Ursula; Ferrari, Elena; Mazzini, Giuliano; Khoronenkova, Svetlana; Grosse, Nicole; van Loon, Barbara; Dianov, Grigory; Hübscher, Ulrich; Maga, Giovanni

2013-01-01

Human DNA polymerase (pol) λ functions in base excision repair and non-homologous end joining. We have previously shown that DNA pol λ is involved in accurate bypass of the two frequent oxidative lesions, 7,8-dihydro-8-oxoguanine and 1,2-dihydro-2-oxoadenine during the S phase. However, nothing is known so far about the relationship of DNA pol λ with the S phase DNA damage response checkpoint. Here, we show that a knockdown of DNA pol λ, but not of its close homologue DNA pol β, results in replication fork stress and activates the S phase checkpoint, slowing S phase progression in different human cancer cell lines. We furthermore show that DNA pol λ protects cells from oxidative DNA damage and also functions in rescuing stalled replication forks. Its absence becomes lethal for a cell when a functional checkpoint is missing, suggesting a DNA synthesis deficiency. Our results provide the first evidence, to our knowledge, that DNA pol λ is required for cell cycle progression and is functionally connected to the S phase DNA damage response machinery in cancer cells. PMID:23118481

An acetyl-L-carnitine switch on mitochondrial dysfunction and rescue in the metabolomics study on aluminum oxide nanoparticles.

PubMed

Li, Xiaobo; Zhang, Chengcheng; Zhang, Xin; Wang, Shizhi; Meng, Qingtao; Wu, Shenshen; Yang, Hongbao; Xia, Yankai; Chen, Rui

2016-01-16

Due to the wide application of engineered aluminum oxide nanoparticles and increased aluminum containing particulate matter suspending in air, exposure of human to nano-scale aluminum oxide nanoparticles (Al2O3 NPs) is becoming inevitable. In the present study, RNA microarray coupled with metabolomics analysis were used to uncover mechanisms underlying cellular responses to Al2O3 NPs and imply the potential rescue. We found that Al2O3 NPs significantly triggered down-regulation of mitochondria-related genes located in complex I, IV and V, which were involved in oxidative phosphorylation and neural degeneration pathways, in human bronchial epithelial (HBE) cells. Subsequent cell- and animal- based assays confirmed that Al2O3 NPs caused mitochondria-dependent apoptosis and oxidative stress either in vitro or in vivo, which were consistent with the trends of gene regulation. To rescue the Al2O3 NPs induced mitochondria dysfunction, disruption of small molecular metabolites of HBE were profiled using metabolomics analysis, which facilitates identification of potential antagonizer or supplement against nanoparticle-involved damages. Supplementation of an antioxidant, acetyl-L-carnitine, completely or partially restored the Al2O3 NPs modulated gene expression levels in mitochondrial complex I, IV and V. It further reduced apoptosis and oxidative damages in both Al2O3 NPs treated HBE cells and animal lung tissues. Thus, our results demonstrate the potential mechanism of respiratory system damages induced by Al2O3 NPs. Meanwhile, based on the metabolomics profiling, application of acetyl-L-carnitine is suggested to ameliorate mitochondria dysfunction associated with Al2O3 NPs.

Oxidative shielding or oxidative stress?

PubMed

Naviaux, Robert K

2012-09-01

In this review I report evidence that the mainstream field of oxidative damage biology has been running fast in the wrong direction for more than 50 years. Reactive oxygen species (ROS) and chronic oxidative changes in membrane lipids and proteins found in many chronic diseases are not the result of accidental damage. Instead, these changes are the result of a highly evolved, stereotyped, and protein-catalyzed "oxidative shielding" response that all eukaryotes adopt when placed in a chemically or microbially hostile environment. The machinery of oxidative shielding evolved from pathways of innate immunity designed to protect the cell from attack and limit the spread of infection. Both oxidative and reductive stress trigger oxidative shielding. In the cases in which it has been studied explicitly, functional and metabolic defects occur in the cell before the increase in ROS and oxidative changes. ROS are the response to disease, not the cause. Therefore, it is not the oxidative changes that should be targeted for therapy, but rather the metabolic conditions that create them. This fresh perspective is relevant to diseases that range from autism, type 1 diabetes, type 2 diabetes, cancer, heart disease, schizophrenia, Parkinson's disease, and Alzheimer disease. Research efforts need to be redirected. Oxidative shielding is protective and is a misguided target for therapy. Identification of the causal chemistry and environmental factors that trigger innate immunity and metabolic memory that initiate and sustain oxidative shielding is paramount for human health.

Anti-oxidative cellular protection effect of fasting-induced autophagy as a mechanism for hormesis.

PubMed

Moore, Michael N; Shaw, Jennifer P; Ferrar Adams, Dawn R; Viarengo, Aldo

2015-06-01

The aim of this investigation was to test the hypothesis that fasting-induced augmented lysosomal autophagic turnover of cellular proteins and organelles will reduce potentially harmful lipofuscin (age-pigment) formation in cells by more effectively removing oxidatively damaged proteins. An animal model (marine snail--common periwinkle, Littorina littorea) was used to experimentally test this hypothesis. Snails were deprived of algal food for 7 days to induce an augmented autophagic response in their hepatopancreatic digestive cells (hepatocyte analogues). This treatment resulted in a 25% reduction in the cellular content of lipofuscin in the digestive cells of the fasting animals in comparison with snails fed ad libitum on green alga (Ulva lactuca). Similar findings have previously been observed in the digestive cells of marine mussels subjected to copper-induced oxidative stress. Additional measurements showed that fasting significantly increased cellular health based on lysosomal membrane stability, and reduced lipid peroxidation and lysosomal/cellular triglyceride. These findings support the hypothesis that fasting-induced augmented autophagic turnover of cellular proteins has an anti-oxidative cytoprotective effect by more effectively removing damaged proteins, resulting in a reduction in the formation of potentially harmful proteinaceous aggregates such as lipofuscin. The inference from this study is that autophagy is important in mediating hormesis. An increase was demonstrated in physiological complexity with fasting, using graph theory in a directed cell physiology network (digraph) model to integrate the various biomarkers. This was commensurate with increased health status, and supportive of the hormesis hypothesis. The potential role of enhanced autophagic lysosomal removal of damaged proteins in the evolutionary acquisition of stress tolerance in intertidal molluscs is discussed and parallels are drawn with the growing evidence for the involvement of autophagy in hormesis and anti-ageing processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Differential responses of juvenile and adult South African abalone (Haliotis midae Linnaeus) to low and high oxygen levels.

PubMed

Vosloo, Andre; Laas, Anél; Vosloo, Dalene

2013-01-01

Marine invertebrates have evolved multiple responses to naturally variable environmental oxygen, all aimed at either maintaining cellular oxygen homeostasis or limiting cellular damage during or after hypoxic or hyperoxic events. We assessed organismal (rates of oxygen consumption and ammonia excretion) and cellular (heat shock protein expression, anti-oxidant enzymes) responses of juvenile and adult abalone exposed to low (~83% of saturation), intermediate (~95% of saturation) and high (~115% of saturation) oxygen levels for one month. Using the Comet assay, we measured DNA damage to determine whether the observed trends in the protective responses were sufficient to prevent oxidative damage to cells. Juveniles were unaffected by moderately hypoxic and hyperoxic conditions. Elevated basal rates of superoxide dismutase, glutathione peroxidase and catalase were sufficient to prevent DNA fragmentation and protein damage. Adults, with their lower basal rate of anti-oxidant enzymes, had increased DNA damage under hypoxic and hyperoxic conditions, indicating that the antioxidant enzymes were unable to prevent oxidative damage under hypoxic and hyperoxic conditions. The apparent insensitivity of juvenile abalone to decreased and increased oxygen might be related to their life history and development in algal and diatom biofilms where they are exposed to extreme diurnal fluctuations in dissolved oxygen levels. Copyright © 2012 Elsevier Inc. All rights reserved.

The role of Hibiscus sabdariffa L. (Roselle) in maintenance of ex vivo murine bone marrow-derived hematopoietic stem cells.

PubMed

Abdul Hamid, Zariyantey; Lin Lin, Winnie Hii; Abdalla, Basma Jibril; Bee Yuen, Ong; Latif, Elda Surhaida; Mohamed, Jamaludin; Rajab, Nor Fadilah; Paik Wah, Chow; Wak Harto, Muhd Khairul Akmal; Budin, Siti Balkis

2014-01-01

Hematopoietic stem cells- (HSCs-) based therapy requires ex vivo expansion of HSCs prior to therapeutic use. However, ex vivo culture was reported to promote excessive production of reactive oxygen species (ROS), exposing HSCs to oxidative damage. Efforts to overcome this limitation include the use of antioxidants. In this study, the role of Hibiscus sabdariffa L. (Roselle) in maintenance of cultured murine bone marrow-derived HSCs was investigated. Aqueous extract of Roselle was added at varying concentrations (0-1000 ng/mL) for 24 hours to the freshly isolated murine bone marrow cells (BMCs) cultures. Effects of Roselle on cell viability, reactive oxygen species (ROS) production, glutathione (GSH) level, superoxide dismutase (SOD) activity, and DNA damage were investigated. Roselle enhanced the survival (P < 0.05) of BMCs at 500 and 1000 ng/mL, increased survival of Sca-1(+) cells (HSCs) at 500 ng/mL, and maintained HSCs phenotype as shown from nonremarkable changes of surface marker antigen (Sca-1) expression in all experimental groups. Roselle increased (P < 0.05) the GSH level and SOD activity but the level of reactive oxygen species (ROS) was unaffected. Moreover, Roselle showed significant cellular genoprotective potency against H2O2-induced DNA damage. Conclusively, Roselle shows novel property as potential supplement and genoprotectant against oxidative damage to cultured HSCs.

In vitro antioxidation activity and genoprotective effect of selected Chinese medicinal herbs.

PubMed

Szeto, Yim Tong; Wong, Shirley Ching Yee; Wong, Julia Wai Ming; Kalle, Wouter; Pak, Sok Cheon

2011-01-01

Some traditional Chinese medicinal seeds and fruits are well known for their antioxidant properties. This research aims to investigate whether Fructus Lycii, Fructus Schisandrae Chinensis, Fructus Ligustri Lucidi and Semen Cuscutae protect DNA from oxidant challenge by hydrogen peroxide (H(2)O(2)). The standard comet assay was used to assess the genoprotective effect of these medicinal herbs. Blood was taken from three healthy adults, aged from 36 to 42. Lymphocytes were isolated and treated with different concentrations of aqueous herbal extracts, while controls were treated with phosphate buffered saline. The lymphocytes were stressed with 50 μM H(2)O(2). Treated cells were embedded in agarose and layered on slides. These sandwiched lymphocytes were lysed and afterwards subjected to an electric field in an alkaline environment. Damaged DNA was pulled out from the nucleus towards the positive electrode as a comet tail; its density was related to the degree of DNA damage. Finally, the slides were stained with fluorescence dye and tails were visually scored for 100 cells. The experiment was repeated three times and DNA damage in treated cells was compared to the controls. There was no statistical difference in DNA damage among the herb treated cells and untreated cells in the comet assay. Our data demonstrated that the selected medicinal herbs did not show in vitro DNA protection in the comet assay against oxidant challenge.

The Role of Hibiscus sabdariffa L. (Roselle) in Maintenance of Ex Vivo Murine Bone Marrow-Derived Hematopoietic Stem Cells

PubMed Central

Abdul Hamid, Zariyantey; Lin Lin, Winnie Hii; Abdalla, Basma Jibril; Bee Yuen, Ong; Latif, Elda Surhaida; Mohamed, Jamaludin; Rajab, Nor Fadilah; Paik Wah, Chow; Budin, Siti Balkis

2014-01-01

Hematopoietic stem cells- (HSCs-) based therapy requires ex vivo expansion of HSCs prior to therapeutic use. However, ex vivo culture was reported to promote excessive production of reactive oxygen species (ROS), exposing HSCs to oxidative damage. Efforts to overcome this limitation include the use of antioxidants. In this study, the role of Hibiscus sabdariffa L. (Roselle) in maintenance of cultured murine bone marrow-derived HSCs was investigated. Aqueous extract of Roselle was added at varying concentrations (0–1000 ng/mL) for 24 hours to the freshly isolated murine bone marrow cells (BMCs) cultures. Effects of Roselle on cell viability, reactive oxygen species (ROS) production, glutathione (GSH) level, superoxide dismutase (SOD) activity, and DNA damage were investigated. Roselle enhanced the survival (P < 0.05) of BMCs at 500 and 1000 ng/mL, increased survival of Sca-1+ cells (HSCs) at 500 ng/mL, and maintained HSCs phenotype as shown from nonremarkable changes of surface marker antigen (Sca-1) expression in all experimental groups. Roselle increased (P < 0.05) the GSH level and SOD activity but the level of reactive oxygen species (ROS) was unaffected. Moreover, Roselle showed significant cellular genoprotective potency against H2O2-induced DNA damage. Conclusively, Roselle shows novel property as potential supplement and genoprotectant against oxidative damage to cultured HSCs. PMID:25405216

Impact of psychostimulants and atomoxetine on the expression of 8-hydroxyguanine glycosylase 1 in human cells.

PubMed

Schmidt, Andreas Johannes; Clement, Hans-Willi; Gebhardt, Stefan; Hemmeter, Ulrich Michael; Schulz, Eberhard; Krieg, Jürgen-Christian; Kircher, Tilo; Heiser, Philip

2010-06-01

Oxidative DNA damage as one sign of reactive oxygen species induced oxidative stress is an important factor in the pathogenesis of various psychiatric disorders. Altered levels of DNA base damage products as well as the expression of the main repair enzyme 8-hydroxyguanine glycosylase 1 have been described. The aim of the present study was to examine the effects of drugs (amphetamine, methylphenidate and atomoxetine) used in the treatment of attention deficit-hyperactivity disorder on the expression of this enzyme via reverse transcriptase-polymerase chain reaction in human neuroblastoma SH-SY5Y and human monocytic U-937 cells at concentrations of 50, 500 and 5,000 ng/ml. We observed decreased expression of this enzyme for all applied substances. In U-937 cells, the significance level was reached after treatment with 5,000 ng/ml amphetamine as well as after treatment with 50, 500 and 5,000 ng/ml atomoxetine. Incubation of SH-SY5Y cells with 50 and 5,000 ng/ml amphetamine and 5,000 ng/ml methylphenidate led to significant decreases of 8-hydroxyguanine glycosylase 1. As a positive correlation between the expression of 8-hydroxyguanine glycosylase 1 and the level of oxidative DNA damage products has been described, we accordingly consider these substances (amphetamine, methylphenidate and atomoxetine) to possibly play a protective role in this process.

Role of Bacillus subtilis Error Prevention Oxidized Guanine System in Counteracting Hexavalent Chromium-Promoted Oxidative DNA Damage

PubMed Central

Santos-Escobar, Fernando; Gutiérrez-Corona, J. Félix

2014-01-01

Chromium pollution is potentially detrimental to bacterial soil communities, compromising carbon and nitrogen cycles that are essential for life on earth. It has been proposed that intracellular reduction of hexavalent chromium [Cr(VI)] to trivalent chromium [Cr(III)] may cause bacterial death by a mechanism that involves reactive oxygen species (ROS)-induced DNA damage; the molecular basis of the phenomenon was investigated in this work. Here, we report that Bacillus subtilis cells lacking a functional error prevention oxidized guanine (GO) system were significantly more sensitive to Cr(VI) treatment than cells of the wild-type (WT) strain, suggesting that oxidative damage to DNA is involved in the deleterious effects of the oxyanion. In agreement with this suggestion, Cr(VI) dramatically increased the ROS concentration and induced mutagenesis in a GO-deficient B. subtilis strain. Alkaline gel electrophoresis (AGE) analysis of chromosomal DNA of WT and ΔGO mutant strains subjected to Cr(VI) treatment revealed that the DNA of the ΔGO strain was more susceptible to DNA glycosylase Fpg attack, suggesting that chromium genotoxicity is associated with 7,8-dihydro-8-oxodeoxyguanosine (8-oxo-G) lesions. In support of this notion, specific monoclonal antibodies detected the accumulation of 8-oxo-G lesions in the chromosomes of B. subtilis cells subjected to Cr(VI) treatment. We conclude that Cr(VI) promotes mutagenesis and cell death in B. subtilis by a mechanism that involves radical oxygen attack of DNA, generating 8-oxo-G, and that such effects are counteracted by the prevention and repair GO system. PMID:24973075

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

PubMed Central

Lee, Yuan-Hao; Sun, Youping; Glickman, Randolph D.

2014-01-01

Ultraviolet (UV) light is a leading cause of diseases, such as skin cancers and cataracts. A main process mediating UV-induced pathogenesis is the production of reactive oxygen species (ROS). Excessive ROS levels induce the formation of DNA adducts (e.g., pyrimidine dimers) and result in stalled DNA replication forks. In addition, ROS promotes phosphorylation of tyrosine kinase-coupled hormone receptors and alters downstream energy metabolism. With respect to the risk of UV-induced photocarcinogenesis and photodamage, the antitumoral and antioxidant functions of natural compounds become important for reducing UV-induced adverse effects. One important question in the field is what determines the differential sensitivity of various types of cells to UV light and how exogenous molecules, such as phytochemicals, protect normal cells from UV-inflicted damage while potentiating tumor cell death, presumably via interaction with intracellular target molecules and signaling pathways. Several endogenous molecules have emerged as possible players mediating UV-triggered DNA damage responses. Specifically, UV activates the PIKK (phosphatidylinositol 3-kinase-related kinase) family members, which include DNA-PKcs, ATM (ataxia telangiectasia mutated) and mTOR (mammalian target of rapamycin), whose signaling can be affected by energy metabolism; however, it remains unclear to what extent the activation of hormone receptors regulates PIKKs and whether this crosstalk occurs in all types of cells in response to UV. This review focuses on proteomic descriptions of the relationships between cellular photosensitivity and the phenotypic expression of the insulin/insulin-like growth receptor. It covers the cAMP-dependent pathways, which have recently been shown to regulate the DNA repair machinery through interactions with the PIKK family members. Finally, this review provides a strategic illustration of how UV-induced mitogenic activity is modulated by the insulin 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. PMID:28250388

Exposure to Heavy Ion Radiation Induces Persistent Oxidative Stress in Mouse Intestine

PubMed Central

Datta, Kamal; Suman, Shubhankar; Kallakury, Bhaskar V. S.; Fornace, Albert J.

2012-01-01

Ionizing radiation-induced oxidative stress is attributed to generation of reactive oxygen species (ROS) due to radiolysis of water molecules and is short lived. Persistent oxidative stress has also been observed after radiation exposure and is implicated in the late effects of radiation. The goal of this study was to determine if long-term oxidative stress in freshly isolated mouse intestinal epithelial cells (IEC) is dependent on radiation quality at a dose relevant to fractionated radiotherapy. Mice (C57BL/6J; 6 to 8 weeks; female) were irradiated with 2 Gy of γ-rays, a low-linear energy transfer (LET) radiation, and intestinal tissues and IEC were collected 1 year after radiation exposure. Intracellular ROS, mitochondrial function, and antioxidant activity in IEC were studied by flow cytometry and biochemical assays. Oxidative DNA damage, cell death, and mitogenic activity in IEC were assessed by immunohistochemistry. Effects of γ radiation were compared to 56Fe radiation (iso-toxic dose: 1.6 Gy; energy: 1000 MeV/nucleon; LET: 148 keV/µm), we used as representative of high-LET radiation, since it's one of the important sources of high Z and high energy (HZE) radiation in cosmic rays. Radiation quality affected the level of persistent oxidative stress with higher elevation of intracellular ROS and mitochondrial superoxide in high-LET 56Fe radiation compared to unirradiated controls and γ radiation. NADPH oxidase activity, mitochondrial membrane damage, and loss of mitochondrial membrane potential were greater in 56Fe-irradiated mice. Compared to γ radiation oxidative DNA damage was higher, cell death ratio was unchanged, and mitotic activity was increased after 56Fe radiation. Taken together our results indicate that long-term functional dysregulation of mitochondria and increased NADPH oxidase activity are major contributing factors towards heavy ion radiation-induced persistent oxidative stress in IEC with potential for neoplastic transformation. PMID:22936983

Temperature stress, anti-oxidative enzyme activity and virus acquisition in Bemisia tabaci (Hemiptera: Aleyrodidae)

USDA-ARS?s Scientific Manuscript database

In most eukaryotic systems, antioxidants provide protection when cells are exposed to stressful environmental conditions. Antioxidants, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase, function in a stepwise series with SOD initially preventing oxidative damage by conve...

The role of operating parameters and oxidative damage mechanisms of advanced chemical oxidation processes in the combat against antibiotic-resistant bacteria and resistance genes present in urban wastewater.

PubMed

Michael-Kordatou, I; Karaolia, P; Fatta-Kassinos, D

2018-02-01

An upsurge in the study of antibiotic resistance in the environment has been observed in the last decade. Nowadays, it is becoming increasingly clear that urban wastewater is a key source of antibiotic resistance determinants, i.e. antibiotic-resistant bacteria and antibiotic resistance genes (ARB&ARGs). Urban wastewater reuse has arisen as an important component of water resources management in the European Union and worldwide to address prolonged water scarcity issues. Especially, biological wastewater treatment processes (i.e. conventional activated sludge), which are widely applied in urban wastewater treatment plants, have been shown to provide an ideal environment for the evolution and spread of antibiotic resistance. The ability of advanced chemical oxidation processes (AOPs), e.g. light-driven oxidation in the presence of H 2 O 2 , ozonation, homogeneous and heterogeneous photocatalysis, to inactivate ARB and remove ARGs in wastewater effluents has not been yet evaluated through a systematic and integrated approach. Consequently, this review seeks to provide an extensive and critical appraisal on the assessment of the efficiency of these processes in inactivating ARB and removing ARGs in wastewater effluents, based on recent available scientific literature. It tries to elucidate how the key operating conditions may affect the process efficiency, while pinpointing potential areas for further research and major knowledge gaps which need to be addressed. Also, this review aims at shedding light on the main oxidative damage pathways involved in the inactivation of ARB and removal of ARGs by these processes. In general, the lack and/or heterogeneity of the available scientific data, as well as the different methodological approaches applied in the various studies, make difficult the accurate evaluation of the efficiency of the processes applied. Besides the operating conditions, the variable behavior observed by the various examined genetic constituents of the microbial community, may be directed by the process distinct oxidative damage mechanisms in place during the application of each treatment technology. For example, it was shown in various studies that the majority of cellular damage by advanced chemical oxidation may be on cell wall and membrane structures of the targeted bacteria, leaving the internal components of the cells relatively intact/able to repair damage. As a result, further in-depth mechanistic studies are required, to establish the optimum operating conditions under which oxidative mechanisms target internal cell components such as genetic material and ribosomal structures more intensively, thus conferring permanent damage and/or death and preventing potential post-treatment re-growth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vitamin D3 contributes to enhanced osteogenic differentiation of MSCs under oxidative stress condition via activating the endogenous antioxidant system.

PubMed

Zhou, J; Wang, F; Ma, Y; Wei, F

2018-06-02

The anti-oxidative effects of vitamin D3 (Vd3) on mesenchymal stem cells (MSCs) have not been studied before. The present study suggested that Vd3 could not only promote the osteogenic differentiation of MSCs under normal condition but also partly protect it from oxidative stress damage by activating the endogenous antioxidant system. Evolving evidence proved that oxidative stress caused by reactive oxygen species (ROS) overproduction might lead to bone loss. Vd3, a commonly used osteogenic induction drug, was proved to exhibit potent anti-oxidative effects on other cell types. The present study aims to investigate the protective effects of Vd3 on oxidative stress-induced dysfunctions of MSCs, as well as its underlying mechanisms. The H 2 O 2 was used as exogenous reactive oxygen species (ROS). The influence of ROS and anti-oxidative protection of Vd3 on MSCs were analyzed too. Multi-techniques were used to assess the beneficial effects of Vd3 on MSCs under oxidative stress condition. The results demonstrated that Vd3 could significantly attenuate the H 2 O 2 -induced cell injury of MSCs via Sirt1/FoxO1 signaling pathway, and reduced the H 2 O 2 exposure-induced intracellular oxidative stress status of MSCs. What's more, the H 2 O 2 exposure resulted in the decreased osteogenic differentiation of MSCs, as evidenced by decreased alkaline phosphatase activity, calcium deposition level, and osteogenic differentiation gene mRNA levels, but the injury was restored via Vd3 administration. The results suggested that Vd3 could not only promote the osteogenic differentiation of osteoblastic cells under normal condition but also partly protect the cell from oxidative stress damage by activating endogenous antioxidant system. The study shed light on the new roles of Vd3 in bone modeling and remodeling regulation.

Taurine and neural cell damage.

PubMed

Saransaari, P; Oja, S S

2000-01-01

The inhibitory amino acid taurine is an osmoregulator and neuromodulator, also exerting neuroprotective actions in neural tissue. We review now the involvement of taurine in neuron-damaging conditions, including hypoxia, hypoglycemia, ischemia, oxidative stress, and the presence of free radicals, metabolic poisons and an excess of ammonia. The brain concentration of taurine is increased in several models of ischemic injury in vivo. Cell-damaging conditions which perturb the oxidative metabolism needed for active transport across cell membranes generally reduce taurine uptake in vitro, immature brain tissue being more tolerant to the lack of oxygen. In ischemia nonsaturable diffusion increases considerably. Both basal and K+-stimulated release of taurine in the hippocampus in vitro is markedly enhanced under cell-damaging conditions, ischemia, free radicals and metabolic poisons being the most potent. Hypoxia, hypoglycemia, ischemia, free radicals and oxidative stress also increase the initial basal release of taurine in cerebellar granule neurons, while the release is only moderately enhanced in hypoxia and ischemia in cerebral cortical astrocytes. The taurine release induced by ischemia is for the most part Ca2+-independent, a Ca2+-dependent mechanism being discernible only in hippocampal slices from developing mice. Moreover, a considerable portion of hippocampal taurine release in ischemia is mediated by the reversal of Na+-dependent transporters. The enhanced release in adults may comprise a swelling-induced component through Cl- channels, which is not discernible in developing mice. Excitotoxic concentrations of glutamate also potentiate taurine release in mouse hippocampal slices. The ability of ionotropic glutamate receptor agonists to evoke taurine release varies under different cell-damaging conditions, the N-methyl-D-aspartate-evoked release being clearly receptor-mediated in ischemia. Neurotoxic ammonia has been shown to provoke taurine release from different brain preparations, indicating that the ammonia-induced release may modify neuronal excitability in hyperammonic conditions. Taurine released simultane ously with an excess of excitatory amino acids in the hippocampus under ischemic and other neuron-damaging conditions may constitute an important protective mechanism against excitotoxicity, counteracting the harmful effects which lead to neuronal death. The release of taurine may prevent excitation from reaching neurotoxic levels.

Silver nanoparticles induced heat shock protein 70, oxidative stress and apoptosis in Drosophila melanogaster.

PubMed

Ahamed, Maqusood; Posgai, Ryan; Gorey, Timothy J; Nielsen, Mark; Hussain, Saber M; Rowe, John J

2010-02-01

Due to the intensive commercial application of silver nanoparticles (Ag NPs), risk assessment of this nanoparticle is of great importance. Our previous in vitro study demonstrated that Ag NPs caused DNA damage and apoptosis in mouse embryonic stem cells and fibroblasts. However, toxicity of Ag NPs in vivo is largely lacking. This study was undertaken to examine the toxic effects of well-characterized polysaccharide coated 10 nm Ag NPs on heat shock stress, oxidative stress, DNA damage and apoptosis in Drosophila melanogaster. Third instar larvae of D. melanogaster were fed a diet of standard cornmeal media mixed with Ag NPs at the concentrations of 50 and 100 microg/ml for 24 and 48 h. Ag NPs up-regulated the expression of heat shock protein 70 and induced oxidative stress in D. melanogaster. Malondialdehyde level, an end product of lipid peroxidation was significantly higher while antioxidant glutathione content was significantly lower in Ag NPs exposed organisms. Activities of antioxidant enzyme superoxide dismutase and catalase were also significantly higher in the organisms exposed to Ag NPs. Furthermore, Ag NPs up-regulated the cell cycle checkpoint p53 and cell signaling protein p38 that are involved in the DNA damage repair pathway. Moreover, activities of caspase-3 and caspase-9, markers of apoptosis were significantly higher in Ag NPs exposed organisms. The results indicate that Ag NPs in D. melanogaster induce heat shock stress, oxidative stress, DNA damage and apoptosis. This study suggests that the organism is stressed and thus warrants more careful assessment of Ag NPs using in vivo models to determine if chronic exposure presents developmental and reproductive toxicity. Copyright 2009 Elsevier Inc. All rights reserved.

A Single Zidovudine (AZT) Administration Delays Hepatic Cell Proliferation by Altering Oxidative State in the Regenerating Rat Liver

PubMed Central

Butanda-Ochoa, Armando; Hernández-Espinosa, Diego Rolando; Olguín-Martínez, Marisela; Sánchez-Sevilla, Lourdes; Rodríguez, Mario R.; Chávez-Rentería, Benito; Aranda-Fraustro, Alberto

2017-01-01

The 3′-azido-3′-deoxythymidine or Zidovudine (AZT) was the first antiretroviral drug used in the treatment of HIV patients, which has good effectiveness but also hepatotoxic side effects that include cell cycle arrest and oxidative/nitrative mitochondrial damage. Whether such an oxidative damage may affect the proliferative-regenerative capacity of liver remains to be clearly specified at doses commonly used in the clinical practice. In this study, we described the oxidative-proliferative effect of AZT administered at a common clinical dose in rat liver submitted to 70% partial hepatectomy (PH). The results indicate that AZT significantly decreased DNA synthesis and the number of mitosis in liver subjected to PH in a synchronized way with the promotion of organelle-selective lipid peroxidation events (especially those observed in plasma membrane and cytosolic fractions) and with liver enzyme release to the bloodstream. Then at the dose used in clinical practice AZT decreased liver regeneration but stimulates oxidative events involved during the proliferation process in a way that each membrane system inside the cell preserves its integrity in order to maintain the cell proliferative process. Here, the induction of large amounts of free ammonia in the systemic circulation could become a factor capable of mediating the deleterious effects of AZT on PH-induced rat liver regeneration. PMID:28479956

Interaction between HSP 70 and iNOS in skeletal muscle injury and repair.

PubMed

Kim, Kijeong

2015-10-01

Muscle injuries are frequently occurred in various sports. The biological process and mechanism of muscle repair after injury are well known through the many studies. This study aimed at presenting heat shock protein and nitric oxide synthase are to respond to muscle damage and repair. This section discusses the results obtained through many articles. Heat shock proteins (HSPs) are considered to play an essential role in protecting cells from damage, preparing them to survive on new environmental challenges. In addition, exercise-induced changes such as heat shock, oxidative, metabolic, muscular, and cytokine stress seem to be responsible for the HSP response to exercise. Also, inducible nitric oxide synthase (iNOS) generates nitric oxide (NO) for prolonged period and causes pathophysiological effects. Furthermore, iNOS is involved in processes such as cell injury, wound repair, embryogenesis, tissue differentiation, and suppression of tumorigenesis. In conclusion, the inhibition of HSP 70 on caspase-3 and apoptosis is associated with its inhibition on iNOS that leads to less NO production.

Nuclear translocation of p19INK4d in response to oxidative DNA damage promotes chromatin relaxation.

PubMed

Sonzogni, Silvina V; Ogara, María F; Castillo, Daniela S; Sirkin, Pablo F; Radicella, J Pablo; Cánepa, Eduardo T

2015-01-01

DNA is continuously exposed to damaging agents that can lead to changes in the genetic information with adverse consequences. Nonetheless, eukaryotic cells have mechanisms such as the DNA damage response (DDR) to prevent genomic instability. The DNA of eukaryotic cells is packaged into nucleosomes, which fold the genome into highly condensed chromatin, but relatively little is known about the role of chromatin accessibility in DNA repair. p19INK4d, a cyclin-dependent kinase inhibitor, plays an important role in cell cycle regulation and cellular DDR. Extensive data indicate that p19INK4d is a critical factor in the maintenance of genomic integrity and cell survival. p19INK4d is upregulated by various genotoxics, improving the repair efficiency for a variety of DNA lesions. The evidence of p19INK4d translocation into the nucleus and its low sequence specificity in its interaction with DNA prompted us to hypothesize that p19INK4d plays a role at an early stage of cellular DDR. In the present study, we demonstrate that upon oxidative DNA damage, p19INK4d strongly binds to and relaxes chromatin. Furthermore, in vitro accessibility assays show that DNA is more accessible to a restriction enzyme when a chromatinized plasmid is incubated in the presence of a protein extract with high levels of p19INK4d. Nuclear protein extracts from cells overexpressing p19INK4d are better able to repair a chromatinized and damaged plasmid. These observations support the notion that p19INK4d would act as a chromatin accessibility factor that allows the access of the repair machinery to the DNA damage site.

Light History Influences the Response of the Marine Cyanobacterium Synechococcus sp. WH7803 to Oxidative Stress1[W][OA

PubMed Central

Blot, Nicolas; Mella-Flores, Daniella; Six, Christophe; Le Corguillé, Gildas; Boutte, Christophe; Peyrat, Anne; Monnier, Annabelle; Ratin, Morgane; Gourvil, Priscillia; Campbell, Douglas A.; Garczarek, Laurence

2011-01-01

Marine Synechococcus undergo a wide range of environmental stressors, especially high and variable irradiance, which may induce oxidative stress through the generation of reactive oxygen species (ROS). While light and ROS could act synergistically on the impairment of photosynthesis, inducing photodamage and inhibiting photosystem II repair, acclimation to high irradiance is also thought to confer resistance to other stressors. To identify the respective roles of light and ROS in the photoinhibition process and detect a possible light-driven tolerance to oxidative stress, we compared the photophysiological and transcriptomic responses of Synechococcus sp. WH7803 acclimated to low light (LL) or high light (HL) to oxidative stress, induced by hydrogen peroxide (H2O2) or methylviologen. While photosynthetic activity was much more affected in HL than in LL cells, only HL cells were able to recover growth and photosynthesis after the addition of 25 μm H2O2. Depending upon light conditions and H2O2 concentration, the latter oxidizing agent induced photosystem II inactivation through both direct damage to the reaction centers and inhibition of its repair cycle. Although the global transcriptome response appeared similar in LL and HL cells, some processes were specifically induced in HL cells that seemingly helped them withstand oxidative stress, including enhancement of photoprotection and ROS detoxification, repair of ROS-driven damage, and regulation of redox state. Detection of putative LexA binding sites allowed the identification of the putative LexA regulon, which was down-regulated in HL compared with LL cells but up-regulated by oxidative stress under both growth irradiances. PMID:21670225

Hemoglobin redox reactions and red blood cell aging.

PubMed

Rifkind, Joseph M; Nagababu, Enika

2013-06-10

The physiological mechanism(s) for recognition and removal of red blood cells (RBCs) from circulation after 120 days of its lifespan is not fully understood. Many of the processes thought to be associated with the removal of RBCs involve oxidative stress. We have focused on hemoglobin (Hb) redox reactions, which is the major source of RBC oxidative stress. The importance of Hb redox reactions have been shown to originate in large parts from the continuous slow autoxidation of Hb producing superoxide and its dramatic increase under hypoxic conditions. In addition, oxidative stress has been shown to be associated with redox reactions that originate from Hb reactions with nitrite and nitric oxide (NO) and the resultant formation of highly toxic peroxynitrite when NO reacts with superoxide released during Hb autoxidation. The interaction of Hb, particularly under hypoxic conditions with band 3 of the RBC membrane is critical for the generating the RBC membrane changes that trigger the removal of cells from circulation. These changes include exposure of antigenic sites, increased calcium leakage into the RBC, and the resultant leakage of potassium out of the RBC causing cell shrinkage and impaired deformability. The need to understand the oxidative damage to specific membrane proteins that result from redox reactions occurring when Hb is bound to the membrane. Proteomic studies that can pinpoint the specific proteins damaged under different conditions will help elucidate the cellular aging processes that result in cells being removed from circulation.

Role of oxidative stress in diabetic retinopathy and the beneficial effects of flavonoids.

PubMed

Ola, Mohammad Shamsul; Al-Dosari, Dalia; Alhomida, Abdullah S

2018-05-15

Diabetic retinopathy (DR) is one of the leading causes of decreased vision and blindness in developed countries. Diabetes-induced metabolic disorder is believed to increase oxidative stress in the retina. This results in deleterious changes through dysregulation of cellular physiology that damages both neuronal and vascular cells. Here in this review, we first highlight the evidence of potential metabolic sources and pathways which increase oxidative stress that contributes to retinal pathology in diabetes. As oxidative stress is a central factor in the pathophysiology of DR, antioxidants therapy would be beneficial towards preventing the retinal damage. A number of experimental studies by us and others showed that dietary flavonoids cause reduction in increased oxidative stress and other beneficial effects in diabetic retina. We then discuss the potential beneficial effects of the six major flavonoid families, such as flavonones, flavanols, flavonols, isoflavones, flavones and anthocyanins, which have been studied to improve retinal damage. Flanonoids, being known antioxidants, may ameliorate the retinal degenerative factors including apoptosis, inflammation and neurodegeneration in the diabetic retina. Therefore, intake of potential dietary flavonoids would limit oxidative stress and thereby prevent the retinal damage, and subsequently the development of DR. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of patchouli alcohol on the regulation of heat shock-induced oxidative stress in IEC-6 cells.

PubMed

Liu, Xiaoxi; Jiang, Linshu; Liu, Fenghua; Chen, Yuping; Xu, Lei; Li, Deyin; Ma, Yunfei; Li, Huanrong; Xu, Jianqin

2016-08-01

Purpose Patchouli alcohol (PA) is used to treat gastrointestinal dysfunction. The purpose of this study was to ascertain the function of PA in the regulated process of oxidative stress in rat intestinal epithelial cells (IEC-6). Materials and methods Oxidative stress was stimulated by exposing IEC-6 cells to heat shock (42 °C for 3 h). IEC-6 cells in treatment groups were pretreated with various concentrations of PA (10, 40, and 80 ng/mL) for 3 h before heat shock. Results Heat shock caused damage to the morphology of IEC-6 cells, and increased reactive oxygen species (ROS) level and malondialdehyde (MDA) content. Moreover, mRNA and protein expression by target genes related to oxidative stress in heat shock were also altered. Specifically, the mRNA expression by HSP70, HSP90, GSH-px, NRF2 nd HO-1were all increased, and Nrf2 and Keap1 protein expression were increased after heat shock. However, pretreatment with PA weakened the level of damage to the cellular morphology, and decreased the MDA content caused by heat shock, indicating PA had cytoprotective activities. Pretreatment with PA at high dose significantly increased generation of intracellular ROS. Compared with the heat shock group alone, PA pretreatment significantly decreased the mRNA expression by HSP70, HSP90, SOD, CAT, GSH-px, KEAP1 and HO-1. Furthermore, the high dose of PA significantly increased Nrf2 protein expression, while both the intermediate and high dose of PA significantly increased HO-1 protein expression. Conclusion Heat-shock-induced oxidative stress in IEC-6 cells, and PA could alleviate the Nrf2-Keap1 cellular oxidative stress responses.

Inhibitory Effect of Lycopene on Amyloid-β-Induced Apoptosis in Neuronal Cells.

PubMed

Hwang, Sinwoo; Lim, Joo Weon; Kim, Hyeyoung

2017-08-16

Alzheimer's disease (AD) is a fatal neurodegenerative disease. Brain amyloid-β deposition is a crucial feature of AD, causing neuronal cell death by inducing oxidative damage. Reactive oxygen species (ROS) activate NF-κB, which induces expression of Nucling. Nucling is a pro-apoptotic factor recruiting the apoptosome complex. Lycopene is an antioxidant protecting from oxidative stress-induced cell damage. We investigated whether lycopene inhibits amyloid-β-stimulated apoptosis through reducing ROS and inhibiting mitochondrial dysfunction and NF-κB-mediated Nucling expression in neuronal SH-SY5Y cells. We prepared cells transfected with siRNA for Nucling or nontargeting control siRNA to determine the role of Nucling in amyloid-β-induced apoptosis. The amyloid-β increased intracellular and mitochondrial ROS levels, apoptotic indices (p53, Bax/Bcl-2 ratio, caspase-3 cleavage), NF-kB activation and Nucling expression, while cell viability, mitochondrial membrane potential, and oxygen consumption rate decreased in SH-SY5Y cells. Lycopene inhibited these amyloid-β-induced alterations. However, amyloid-β did not induce apoptosis, determined by cell viability and apoptotic indices (p53, Bax/Bcl-2 ratio, caspase-3 cleavage), in the cells transfected with siRNA for Nucling. Lycopene inhibited apoptosis by reducing ROS, and by inhibiting mitochondrial dysfunction and NF-κB-target gene Nucling expression in neuronal cells. Lycopene may be beneficial for preventing oxidative stress-mediated neuronal death in patients with neurodegeneration.

Soluble Factors Released by Endogenous Viable Cells Enhance the Antioxidant and Chemoattractive Activities of Cryopreserved Amniotic Membrane

PubMed Central

Duan-Arnold, Yi; Gyurdieva, Alexandra; Johnson, Amy; Jacobstein, Douglas A.; Danilkovitch, Alla

2015-01-01

Objective: Regulation of oxidative stress and recruitment of key cell types are activities of human amniotic membrane (hAM) that contribute to its benefits for wound treatment. Progress in tissue preservation has led to commercialization of hAM. The majority of hAM products are devitalized with various degrees of matrix alteration. Data show the importance of hAM matrix preservation, but little is known about the advantages of retaining viable endogenous cells. In this study, we compared the antioxidant and chemoattractive properties of viable intact cryopreserved hAM (int-hAM) and devitalized cryopreserved hAM (dev-hAM) to determine the benefits of cell preservation. Approach: We evaluated the ability of int-hAM and dev-hAM to protect fibroblasts from oxidant-induced cell damage, to suppress oxidants, and to recruit fibroblasts and keratinocytes in vitro. Results: Both the int-hAM–derived conditioned medium (CM) and the int-hAM tissue rescued significantly more fibroblasts from oxidant-induced damage than dev-hAM (844% and 93% more, respectively). The int-hAM CM showed a 202% greater antioxidant capacity than dev-hAM. The int-hAM CM enhanced the recruitment of fibroblasts and normal and diseased keratinocytes to a greater extent than dev-hAM (1,555%, 315%, and 151% greater, respectively). Innovation and Conclusion: Int-hAM, in which all native components are preserved, including endogenous viable cells, demonstrated a significantly greater antioxidant and fibroblast and keratinocyte chemoattractive potential compared to dev-hAM, in which viable cells are destroyed. The release of soluble factors that protect fibroblasts from oxidative injury by hAM containing viable cells is a mechanism of hAM antioxidant activity, which is a novel finding of this study. PMID:26029483

Effects of Lycium barbarum Polysaccharides on Apoptosis, Cellular Adhesion, and Oxidative Damage in Bone Marrow Mononuclear Cells of Mice Exposed to Ionizing Radiation Injury

PubMed Central

Zhou, Jing; Pang, Hua; Li, Wenbo; Liu, Qiong; Xu, Lu; Liu, Qian; Liu, Ying

2016-01-01

Lycium barbarum has been used for more than 2500 years as a traditional herb and food in China. We investigated the effects of Lycium barbarum polysaccharides (LBP) on apoptosis, oxidative damage, and expression of adhesion molecules in bone marrow mononuclear cells (BMNC) of mice injured by ionizing radiation. Kunming mice were exposed to X-rays; then mice in the LBP groups were continuously injected with various concentrations of LBP intraperitoneally for 14 days. Mice in the control group were continuously injected with normal saline (NS) by the same route for 14 days. A normal group was set up. After 1, 7, and 14 days of treatment, mice were killed and BMNC were extracted. Cell cycle, apoptosis, and the expression of adhesion molecules CD44 and CD49d were detected by flow cytometry. The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were identified by colorimetric analyses. LBP significantly decreased the percentage of G0/G1 phase, apoptosis, MDA level, and expression of CD44 and CD49d and distinctly increased the activity of SOD. LBP showed a protective effect on BMNC against ionizing radiation-induced apoptosis and oxidative damage and altered the expression of adhesion molecule. PMID:27314019

A study to evaluate the effect of nootropic drug-piracetam on DNA damage in leukocytes and macrophages.

PubMed

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.

Amplification of proinflammatory phenotype, damage, and weakness by oxidative stress in the diaphragm muscle of mdx mice.

PubMed

Kim, Jong-Hee; Lawler, John M

2012-05-01

Duchenne muscular dystrophy (DMD) is a common and devastating type of childhood-onset muscular dystrophy, attributed to an X-linked defect in the gene that encodes dystrophin. Myopathy with DMD is most pronounced in the diaphragm muscle and fast-twitch limb muscles and is dependent upon susceptibility to damage, inflammatory cell infiltration, and proinflammatory signaling (nuclear factor-κB; NF-κB). Although recent papers have reawakened the notion that oxidative stress links inflammatory signaling with pathology in DMD in limb muscle, the importance of redox mechanisms had been clouded by inconsistent results from indirect scavenger approaches, including in the diaphragm muscle. Therefore, we used a novel catalytic mimetic of superoxide dismutase and catalase (EUK-134) as a direct scavenger of oxidative stress in myopathy in the diaphragm of the mdx mouse model. EUK-134 reduced 4-hydroxynonenal and total hydroperoxides, markers of oxidative stress in the mdx diaphragm. EUK-134 also attenuated positive staining of macrophages and T-cells as well as activation of NF-κB and p65 protein abundance. Moreover, EUK-134 ameliorated markers of muscle damage including internalized nuclei, variability of cross-sectional area, and type IIc fibers. Finally, impairment of contractile force was partially rescued by EUK-134 in the diaphragm of mdx mice. We conclude that oxidative stress amplifies DMD pathology in the diaphragm muscle. Copyright © 2012 Elsevier Inc. All rights reserved.

Dietary antioxidants prevent age-related retinal pigment epithelium actin damage and blindness in mice lacking αvβ5 integrin

PubMed Central

Yu, Chia-Chia; Nandrot, Emeline F.; Dun, Ying; Finnemann, Silvia C.

2011-01-01

In the aging human eye, oxidative damage and accumulation of pro-oxidant lysosomal lipofuscin cause functional decline of the retinal pigment epithelium (RPE), which contributes to age-related macular degeneration. In mice with an RPE-specific phagocytosis defect due to lack of αvβ5 integrin receptors, RPE accumulation of lipofuscin suggests that the age-related blindness we previously described in this model may also result from oxidative stress. Cellular and molecular targets of oxidative stress in the eye remain poorly understood. Here we identify actin among 4-hydroxynonenal (HNE) adducts formed specifically in β5−/− RPE but not neural retina with age. HNE modification directly correlated with loss of resistance of actin to detergent extraction, suggesting cytoskeletal damage in aging RPE. Dietary enrichment with natural antioxidants grapes or marigold extract containing macular pigments lutein/zeaxanthin was sufficient to prevent HNE-adduct formation, actin solubility, lipofuscin accumulation, and age-related cone and rod photoreceptor dysfunction in β5−/− mice. Acute generation of HNE-adducts directly destabilized actin but not tubulin cytoskeletal elements of RPE cells. These findings identify destabilization of the actin cytoskeleton as a consequence of physiological, sublethal oxidative burden of RPE cells in vivo that is associated with age-related blindness and that can be prevented by consuming an antioxidant-rich diet. PMID:22178979

Toxicological and pharmacological concerns on oxidative stress and related diseases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saeidnia, Soodabeh; College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon; Abdollahi, Mohammad, E-mail: Mohammad@TUMS.Ac.Ir

2013-12-15

Although reactive oxygen species (ROS) such as superoxide, hydrogen peroxide and hydroxyl radical are generated as the natural byproduct of normal oxygen metabolism, they can create oxidative damage via interaction with bio-molecules. The role of oxidative stress as a remarkable upstream part is frequently reported in the signaling cascade of inflammation as well as chemo attractant production. Even though hydrogen peroxide can control cell signaling and stimulate cell proliferation at low levels, in higher concentrations it can initiate apoptosis and in very high levels may create necrosis. So far, the role of ROS in cellular damage and death is wellmore » documented with implicating in a broad range of degenerative alterations e.g. carcinogenesis, aging and other oxidative stress related diseases (OSRDs). Reversely, it is cleared that antioxidants are potentially able to suppress (at least in part) the immune system and to enhance the normal cellular protective responses to tissue damage. In this review, we aimed to provide insights on diverse OSRDs, which are correlated with the concept of oxidative stress as well as its cellular effects that can be inhibited by antioxidants. Resveratrol, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, statins, nebivolol and carvedilol, pentaerythritol tetranitrate, mitochondria-targeted antioxidants, and plant-derived drugs (alone or combined) are the potential medicines that can be used to control OSRD.« less

Alpha-tocopherol and alpha-tocopheryl quinone levels in cervical intraepithelial neoplasia and cervical cancer.

PubMed

Palan, Prabhudas R; Woodall, Angela L; Anderson, Patrick S; Mikhail, Magdy S

2004-05-01

alpha-Tocopherol is a potent antioxidant that protects cell membranes against oxidative damage. Red blood cell alpha-tocopherol levels reflect membrane alpha-tocopherol concentrations, and altered levels may suggest membrane damage. The objective of this study was to determine the levels of alpha-tocopherol and alpha-tocopheryl quinone, the oxidized product of alpha-tocopherol, in plasma and red blood cells that were obtained from control subjects and patients with cervical intraepithelial neoplasia and cervical cancer. In this cross-sectional study, 72 women, (32 African American and 40 Hispanic) were recruited. Among these subjects, 37 women had cervical intraepithelial neoplasia; 14 women had cervical cancer, and 21 women were considered control subjects, who had normal Papanicolaou test results. alpha-Tocopherol and alpha-tocopheryl quinone levels were determined in red blood cell and plasma by high-pressure liquid chromatography. Plasma levels of alpha-tocopherol and alpha-tocopheryl quinone were decreased significantly (P=.012 and=.005, respectively, by Kruskal-Wallis test) in study groups compared with the control group; red blood cell levels of alpha-tocopherol and alpha-tocopheryl quinone were not altered significantly. The lower alpha-tocopherol level that was observed in this study is consistent with our previous reports of decreased antioxidant concentrations and increased oxidative stress in women with cervical intraepithelial neoplasia. Unaltered red blood cell alpha-tocopherol and alpha-tocopheryl quinone levels suggest undamaged cell membrane. Further studies are needed to investigate the potential role of oxidative stress in cervical intraepithelial neoplasia.

Titanium-doped cerium oxide nanoparticles protect cells from hydrogen peroxide-induced apoptosis

PubMed Central

Clark, Andrea; Zhu, Aiping; Petty, Howard R.

2014-01-01

To develop new nanoparticle materials possessing anti-oxidative capacity with improved physical characteristics, we have studied titanium-doped cerium oxide (CeTiO2) nanoparticles. CeTiO2 nanoparticles had a mode diameter of 15-20 nm. These nanoparticles demonstrated catalase activity, and did not promote the activation of hemolytic or cytolytic pathways in living cells. Using surface plasmon resonance enhanced microscopy, we find that these nanoparticles associate with cells. Transmission electron microscopy studies demonstrated that these nanoparticles accumulate within the vacuolar compartment of cells. Importantly, CeTiO2 nanoparticles decrease hydrogen peroxide-mediated apoptosis of cells as judged by the reduced cleavage of a caspase 3-sensitive label. CeTiO2 nanoparticles may contribute to deflecting tissue damage in a broad spectrum of oxidant-mediated diseases, such as macular degeneration and Alzheimer's disease. PMID:24791147

Evaluation of cytotoxicity and oxidative DNA damaging effects of di(2-ethylhexyl)-phthalate (DEHP) and mono(2-ethylhexyl)-phthalate (MEHP) on MA-10 Leydig cells and protection by selenium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erkekoglu, Pinar; Hacettepe University, Faculty of Pharmacy, Department of Toxicology, 06100 Ankara; Rachidi, Walid

2010-10-01

Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used phthalate derivative, inevitable environmental exposure of which is suspected to contribute to the increasing incidence of testicular dysgenesis syndrome in humans. Oxidative stress and mitochondrial dysfunction in germ cells are suggested to contribute to phthalate-induced disruption of spermatogenesis in rodents, and Leydig cells are one of the main targets of phthalates' testicular toxicity. Selenium is known to be involved in the modulation of intracellular redox equilibrium, and plays a critical role in testis, sperm, and reproduction. This study was aimed to investigate the oxidative stress potential of DEHP and its consequences in testicularmore » cells, and examine the possible protective effects of selenium using the MA-10 mouse Leydig tumor cell line as a model. In the presence and absence of selenium compounds [30 nM sodium selenite (SS), and 10 {mu}M selenomethionine (SM)], the effects of exposure to DEHP and its main metabolite mono(2-ethylhexyl)-phthalate (MEHP) on the cell viability, enzymatic and non-enzymatic antioxidant status, ROS production, p53 expression, and DNA damage by alkaline Comet assay were investigated. The overall results of this study demonstrated the cytotoxicity and genotoxicity potential of DEHP, where MEHP was found to be more potent than the parent compound. SS and SM produced almost the same level of protection against antioxidant status modifying effects, ROS and p53 inducing potentials, and DNA damaging effects of the two phthalate derivatives. It was thus shown that DEHP produced oxidative stress in MA-10 cells, and selenium supplementation appeared to be an effective redox regulator in the experimental conditions used in this study, emphasizing the critical importance of the appropriate selenium status.« less

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

PubMed

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 < 0.001). Mean values and standard deviation were 32 (9), 28 (9), 21 (7) arbitrary unit, respectively. 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.

Oxidative Lung Damage Resulting from Repeated Exposure to Radiation and Hyperoxia Associated with Space Exploration.

PubMed

Pietrofesa, Ralph A; Turowski, Jason B; Arguiri, Evguenia; Milovanova, Tatyana N; Solomides, Charalambos C; Thom, Stephen R; Christofidou-Solomidou, Melpo

2013-09-30

Spaceflight missions may require crewmembers to conduct Extravehicular Activities (EVA) for repair, maintenance or scientific purposes. Pre-breathe protocols in preparation for an EVA entail 100% hyperoxia exposure that may last for a few hours (5-8 hours), and may be repeated 2-3 times weekly. Each EVA is associated with additional challenges such as low levels of total body cosmic/galactic radiation exposure that may present a threat to crewmember health and therefore, pose a threat to the success of the mission. We have developed a murine model of combined, hyperoxia and radiation exposure (double-hit) in the context of evaluating countermeasures to oxidative lung damage associated with space flight. In the current study, our objective was to characterize the early and chronic effects of repeated single and double-hit challenge on lung tissue using a novel murine model of repeated exposure to low-level total body radiation and hyperoxia. This is the first study of its kind evaluating lung damage relevant to space exploration in a rodent model. Mouse cohorts (n=5-15/group) were exposed to repeated: a) normoxia; b) >95% O 2 (O 2 ); c) 0.25Gy single fraction gamma radiation (IR); or d) a combination of O 2 and IR (O 2 +IR) given 3 times per week for 4 weeks. Lungs were evaluated for oxidative damage, active TGFβ1 levels, cell apoptosis, inflammation, injury, and fibrosis at 1, 2, 4, 8, 12, 16, and 20 weeks post-initiation of exposure. Mouse cohorts exposed to all challenge conditions displayed decreased bodyweight compared to untreated controls at 4 and 8 weeks post-challenge initiation. Chronic oxidative lung damage to lipids (malondialdehyde levels), DNA (TUNEL, cleaved Caspase 3, cleaved PARP positivity) leading to apoptotic cell death and to proteins (nitrotyrosine levels) was elevated all treatment groups. Importantly, significant systemic oxidative stress was also noted at the late phase in mouse plasma, BAL fluid, and urine. Importantly, however, late oxidative damage across all parameters that we measured was significantly higher than controls in all cohorts but was exacerbated by the combined exposure to O 2 and IR. Additionally, impaired levels of arterial blood oxygenation were noted in all exposure cohorts. Significant but transient elevation of lung tissue fibrosis ( p <0.05), determined by lung hydroxyproline content, was detected as early as 2 week in mice exposed to challenge conditions and persisted for 4-8 weeks only. Interestingly, active TGFβ1 levels in +BAL fluid was also transiently elevated during the exposure time only (1-4 weeks). Inflammation and lung edema/lung injury was also significantly elevated in all groups at both early and late time points, especially the double-hit group. We have characterized significant, early and chronic lung changes consistent with oxidative tissue damage in our murine model of repeated radiation and hyperoxia exposure relevant to space travel. Lung tissue changes, detectable several months after the original exposure, include significant oxidative lung damage (lipid peroxidation, DNA damage and protein nitrosative stress) and increased pulmonary fibrosis. These findings, along with increased oxidative stress in diverse body fluids and the observed decreases in blood oxygenation levels in all challenge conditions (whether single or in combination), lead us to conclude that in our model of repeated exposure to oxidative stressors, chronic tissue changes are detected that persist even months after the exposure to the stressor has ended. This data will provide useful information in the design of countermeasures to tissue oxidative damage associated with space exploration.