scholarly journals Brewer’s Spent Grains Protects against Oxidative DNA Damage in Saccharomyces cerevisiae

2017 ◽  
Vol 9 (7) ◽  
pp. 12
Author(s):  
Manuela M. Moreira ◽  
Daniel O. Carvalho ◽  
Rui Oliveira ◽  
Björn Johansson ◽  
Luís F. Guido

Brewer’s spent grain (BSG), obtained from barley malt during brewing, contains high amounts of phenolic acids, predominantly ferulic and p-coumaric acids. The protective effects of BSG extracts against oxidative DNA damage induced by H2O2 in Saccharomyces cerevisiae cells were investigated using an optimized yeast comet assay and flow cytometry. The results indicated that BSG extracts from black malt exhibited a 5-fold reduction in the genotoxic effects of H2O2, compared to the 2-fold decrease by the BSG extracts from pilsen malts. Flow cytometry analysis with dichlorofluorescein diacetate demonstrated that the intracellular oxidation of S. cerevisiae is also reduced to approximately 50% in the presence of 20-fold diluted BSG extracts. BSG extracts obtained from pilsen and black malt types exert dose-dependent protective properties against the genotoxic effects induced by ROS and decrease intracellular oxidation of yeast cells.

2016 ◽  
Vol 64 (4) ◽  
pp. 961.1-961
Author(s):  
S Kim ◽  
P Cheresh ◽  
RP Jablonski ◽  
DW Kamp ◽  
M Eren ◽  
...  

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


2018 ◽  
Vol 115 (30) ◽  
pp. E7081-E7090 ◽  
Author(s):  
Laura E. Bowie ◽  
Tamara Maiuri ◽  
Melanie Alpaugh ◽  
Michelle Gabriel ◽  
Nicolas Arbez ◽  
...  

The huntingtin N17 domain is a modulator of mutant huntingtin toxicity and is hypophosphorylated in Huntington’s disease (HD). We conducted high-content analysis to find compounds that could restore N17 phosphorylation. One lead compound from this screen was N6-furfuryladenine (N6FFA). N6FFA was protective in HD model neurons, and N6FFA treatment of an HD mouse model corrects HD phenotypes and eliminates cortical mutant huntingtin inclusions. We show that N6FFA restores N17 phosphorylation levels by being salvaged to a triphosphate form by adenine phosphoribosyltransferase (APRT) and used as a phosphate donor by casein kinase 2 (CK2). N6FFA is a naturally occurring product of oxidative DNA damage. Phosphorylated huntingtin functionally redistributes and colocalizes with CK2, APRT, and N6FFA DNA adducts at sites of induced DNA damage. We present a model in which this natural product compound is salvaged to provide a triphosphate substrate to signal huntingtin phosphorylation via CK2 during low-ATP stress under conditions of DNA damage, with protective effects in HD model systems.


2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Rui Yao ◽  
Pei Zhou ◽  
Chengjin Wu ◽  
Liming Liu ◽  
Jing Wu

ABSTRACT In Saccharomyces cerevisiae, Y family DNA polymerase Rev1 is involved in the repair of DNA damage by translesion DNA synthesis (TLS). In the current study, to elucidate the role of Rev1 in oxidative stress-induced DNA damage in S. cerevisiae, REV1 was deleted and overexpressed; transcriptome analysis of these mutants along with the wild-type strain was performed to screen potential genes that could be associated with REV1 during response to DNA damage. When the yeast cells were treated with 2 mM H2O2, the deletion of REV1 resulted in a 1.5- and 2.8-fold decrease in the survival rate and mutation frequency, respectively, whereas overexpression of REV1 increased the survival rate and mutation frequency by 1.1- and 2.9-fold, respectively, compared to the survival rate and mutation frequency of the wild-type strain. Transcriptome and phenotypic analyses identified that Sml1 aggravated oxidative stress in the yeast cells by inhibiting the activity of Rev1. This inhibition was due to the physical interaction between the BRCA1 C terminus (BRCT) domain of Rev1 and amino acid residues 36 to 70 of Sml1; the cell survival rate and mutation frequency increased by 1.8- and 3.1-fold, respectively, when this interaction was blocked. We also found that Sml1 inhibited Rev1 phosphorylation under oxidative stress and that deletion of SML1 increased the phosphorylation of Rev1 by 46%, whereas overexpression of SML1 reduced phosphorylation of Rev1. Overall, these findings demonstrate that Sml1 could be a novel regulator that mediates Rev1 dephosphorylation to inhibit its activity during oxidative stress. IMPORTANCE Rev1 was critical for cell growth in S. cerevisiae, and the deletion of REV1 caused a severe growth defect in cells exposed to oxidative stress (2 mM H2O2). Furthermore, we found that Sml1 physically interacted with Rev1 and inhibited Rev1 phosphorylation, thereby inhibiting Rev1 DNA antioxidant activity. These findings indicate that Sml1 could be a novel regulator for Rev1 in response to DNA damage by oxidative stress.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yu Zhang ◽  
Jian-feng Xiao ◽  
He-feng Yang ◽  
Yang Jiao ◽  
Wei-wei Cao ◽  
...  

The present study investigated the antiapoptotic and antigenotoxic capabilities of N-acetyl cysteine- (NAC-) containing polymethyl methacrylate (PMMA) resin. An in vitro Transwell insert model was used to mimic the clinical provisional restorations placed on vital teeth. Various parameters associated with cell apoptosis and genotoxicity were investigated to obtain a deeper insight into the underlying mechanisms. The exposure of human dental pulp cell (hDPC) cultures to the PMMA resin (Unifast Trad™) resulted in a rapid increase in reactive oxygen species (ROS) level beginning at 1 h, which was followed by time-dependent cell detachment and overt death. The formation of γ-H2AX and cell cycle G1 phase arrest indicated that oxidative DNA damage occurred as a result of the interactions between DNA bases and ROS, beyond the capacities of cellular redox regulation. Such oxidative DNA damage triggers the activation of p53 via the ataxia telangiectasia mutated (ATM) signaling pathway and the induction of intrinsic mitochondrial apoptosis. Oxidative stress, cell apoptosis, and DNA damage induced by the PMMA resin were recovered to almost the level of untreated controls by the incorporation of NAC. The results indicate that the PMMA resin induced the intrinsic mitochondrial apoptosis as a consequence of p53 activation via the ATM pathway in response to oxidative DNA damage. More importantly, the incorporation of NAC as a novel component into the Unifast Trad™ PMMA resin offers protective effects against cell apoptosis and genotoxicity. This procedure represents a beneficial strategy for developing more biocompatible PMMA-based resin materials.


1999 ◽  
Vol 19 (5) ◽  
pp. 3779-3787 ◽  
Author(s):  
Ingrun Alseth ◽  
Lars Eide ◽  
Manuela Pirovano ◽  
Torbjørn Rognes ◽  
Erling Seeberg ◽  
...  

ABSTRACT Endonuclease III from Escherichia coli is the prototype of a ubiquitous DNA repair enzyme essential for the removal of oxidized pyrimidine base damage. The yeast genome project has revealed the presence of two genes in Saccharomyces cerevisiae,NTG1 and NTG2, encoding proteins with similarity to endonuclease III. Both contain the highly conserved helix-hairpin-helix motif, whereas only one (Ntg2) harbors the characteristic iron-sulfur cluster of the endonuclease III family. We have characterized these gene functions by mutant and enzyme analysis as well as by gene expression and intracellular localization studies. Targeted gene disruption of NTG1 and NTG2produced mutants with greatly increased spontaneous and hydrogen peroxide-induced mutation frequency relative to the wild type, and the mutation response was further increased in the double mutant. Both enzymes were found to remove thymine glycol and 2,6-diamino-4-hydroxy-5-N-methylformamidopyrimidine (faPy) residues from DNA with high efficiency. However, on UV-irradiated DNA, saturating concentrations of Ntg2 removed only half of the cytosine photoproducts released by Ntg1. Conversely, 5-hydroxycytosine was removed efficiently only by Ntg2. The enzymes appear to have different reaction modes, as judged from much higher affinity of Ntg2 for damaged DNA and more efficient borhydride trapping of Ntg1 to abasic sites in DNA despite limited DNA binding. Northern blot and promoter fusion analysis showed that NTG1 is inducible by cell exposure to DNA-damaging agents, whereas NTG2 is constitutively expressed. Ntg2 appears to be a nuclear enzyme, whereas Ntg1 was sorted both to the nucleus and to the mitochondria. We conclude that functions of both NTG1 and NTG2 are important for removal of oxidative DNA damage in yeast.


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