scholarly journals Discovery of the Involvement in DNA Oxidative Damage of Human Sperm Nuclear Basic Proteins of Healthy Young Men Living in Polluted Areas

2020 ◽  
Vol 21 (12) ◽  
pp. 4198 ◽  
Author(s):  
Gennaro Lettieri ◽  
Giovanni D’Agostino ◽  
Elena Mele ◽  
Carolina Cardito ◽  
Rosa Esposito ◽  
...  

DNA oxidative damage is one of the main concerns being implicated in severe cell alterations, promoting different types of human disorders and diseases. For their characteristics, male gametes are the most sensitive cells to the accumulation of damaged DNA. We have recently reported the relevance of arginine residues in the Cu(II)-induced DNA breakage of sperm H1 histones. In this work, we have extended our previous findings investigating the involvement of human sperm nuclear basic proteins on DNA oxidative damage in healthy males presenting copper and chromium excess in their semen. We found in 84% of those males an altered protamines/histones ratio and a different DNA binding mode even for those presenting a canonical protamines/histones ratio. Furthermore, all the sperm nuclear basic proteins from these samples that resulted were involved in DNA oxidative damage, supporting the idea that these proteins could promote the Fenton reaction in DNA proximity by increasing the availability of these metals near the binding surface of DNA. In conclusion, our study reveals a new and unexpected behavior of human sperm nuclear basic proteins in oxidative DNA damage, providing new insights for understanding the mechanisms related to processes in which oxidative DNA damage is implicated.

The Analyst ◽  
2021 ◽  
Author(s):  
Jing Zhou ◽  
Dan Yang ◽  
Guohui Liu ◽  
Siying Li ◽  
Wennan Feng ◽  
...  

Guanine (G) oxidation products, such as 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-oxo-guanine (8-OXOG), have been widely studied as promising biomarkers for DNA oxidative damage.


1998 ◽  
Vol 45 (1) ◽  
pp. 183-190 ◽  
Author(s):  
L Fillion ◽  
A Collins ◽  
S Southon

Epidemiological studies have revealed a strong correlation between high intake of fruit and vegetables and low incidence of certain cancers. Micronutrients present in these foods are thought to decrease free radical attack on DNA and hence protect against mutations that cause cancer, but the fine details of the causal mechanism have still to be elucidated. Whether dietary factors can modulate DNA repair--a crucial element in the avoidance of carcinogenesis--is an intriguing question that has not yet been satisfactorily answered. In order to investigate the effects of beta-carotene on oxidative damage and its repair, volunteers were given a single 45 mg dose and lymphocytes taken before and after the supplement were treated in vitro with H2O2. DNA strand breaks and oxidised pyrimidines were measured at intervals, to monitor the removal of oxidative DNA damage. We found inter-individual variations in response. In cases where the baseline plasma beta-carotene concentration was high, or where supplementation increased the plasma concentration, recovery from oxidative damage (i.e. removal of both oxidised pyrimidines and strand breaks) was relatively rapid. However, what seems to be an enhancement of repair might in fact represent an amelioration of the continuing oxidative stress encountered by the lymphocytes under in vitro culture conditions. We found that culture in a 5% oxygen atmosphere enhanced recovery of lymphocytes from H2O2 damage.


2019 ◽  
Vol 34 (10) ◽  
pp. 1876-1890 ◽  
Author(s):  
M J Xavier ◽  
B Nixon ◽  
S D Roman ◽  
R J Scott ◽  
J R Drevet ◽  
...  

Abstract STUDY QUESTION Do all regions of the paternal genome within the gamete display equivalent vulnerability to oxidative DNA damage? SUMMARY ANSWER Oxidative DNA damage is not randomly distributed in mature human spermatozoa but is instead targeted, with particular chromosomes being especially vulnerable to oxidative stress. WHAT IS KNOWN ALREADY Oxidative DNA damage is frequently encountered in the spermatozoa of male infertility patients. Such lesions can influence the incidence of de novo mutations in children, yet it remains to be established whether all regions of the sperm genome display equivalent susceptibility to attack by reactive oxygen species. STUDY DESIGN, SIZE, DURATION Human spermatozoa obtained from normozoospermic males (n = 8) were split into equivalent samples and subjected to either hydrogen peroxide (H2O2) treatment or vehicle controls before extraction of oxidized DNA using a modified DNA immunoprecipitation (MoDIP) protocol. Specific regions of the genome susceptible to oxidative damage were identified by next-generation sequencing and validated in the spermatozoa of normozoospermic males (n = 18) and in patients undergoing infertility evaluation (n = 14). PARTICIPANTS/MATERIALS, SETTING, METHODS Human spermatozoa were obtained from normozoospermic males and divided into two identical samples prior to being incubated with either H2O2 (5 mm, 1 h) to elicit oxidative stress or an equal volume of vehicle (untreated controls). Alternatively, spermatozoa were obtained from fertility patients assessed as having high basal levels of oxidative stress within their spermatozoa. All semen samples were subjected to MoDIP to selectively isolate oxidized DNA, prior to sequencing of the resultant DNA fragments using a next-generation whole-genomic sequencing platform. Bioinformatic analysis was then employed to identify genomic regions vulnerable to oxidative damage, several of which were selected for real-time quantitative PCR (qPCR) validation. MAIN RESULTS AND THE ROLE OF CHANCE Approximately 9000 genomic regions, 150–1000 bp in size, were identified as highly vulnerable to oxidative damage in human spermatozoa. Specific chromosomes showed differential susceptibility to damage, with chromosome 15 being particularly sensitive to oxidative attack while the sex chromosomes were protected. Susceptible regions generally lay outside protamine- and histone-packaged domains. Furthermore, we confirmed that these susceptible genomic sites experienced a dramatic (2–15-fold) increase in their burden of oxidative DNA damage in patients undergoing infertility evaluation compared to normal healthy donors. LIMITATIONS, REASONS FOR CAUTION The limited number of samples analysed in this study warrants external validation, as do the implications of our findings. Selection of male fertility patients was based on high basal levels of oxidative stress within their spermatozoa as opposed to specific sub-classes of male factor infertility. WIDER IMPLICATIONS OF THE FINDINGS The identification of genomic regions susceptible to oxidation in the male germ line will be of value in focusing future analyses into the mutational load carried by children in response to paternal factors such as age, the treatment of male infertility using ART and paternal exposure to environmental toxicants. STUDY FUNDING/COMPETING INTEREST(S) Project support was provided by the University of Newcastle’s (UoN) Priority Research Centre for Reproductive Science. M.J.X. was a recipient of a UoN International Postgraduate Research Scholarship. B.N. is the recipient of a National Health and Medical Research Council of Australia Senior Research Fellowship. Authors declare no conflict of interest.


2007 ◽  
Vol 189 (15) ◽  
pp. 5504-5514 ◽  
Author(s):  
Signe Saumaa ◽  
Andres Tover ◽  
Mariliis Tark ◽  
Radi Tegova ◽  
Maia Kivisaar

ABSTRACT Oxidative damage of DNA is a source of mutation in living cells. Although all organisms have evolved mechanisms of defense against oxidative damage, little is known about these mechanisms in nonenteric bacteria, including pseudomonads. Here we have studied the involvement of oxidized guanine (GO) repair enzymes and DNA-protecting enzyme Dps in the avoidance of mutations in starving Pseudomonas putida. Additionally, we examined possible connections between the oxidative damage of DNA and involvement of the error-prone DNA polymerase (Pol)V homologue RulAB in stationary-phase mutagenesis in P. putida. Our results demonstrated that the GO repair enzymes MutY, MutM, and MutT are involved in the prevention of base substitution mutations in carbon-starved P. putida. Interestingly, the antimutator effect of MutT was dependent on the growth phase of bacteria. Although the lack of MutT caused a strong mutator phenotype under carbon starvation conditions for bacteria, only a twofold increased effect on the frequency of mutations was observed for growing bacteria. This indicates that MutT has a backup system which efficiently complements the absence of this enzyme in actively growing cells. The knockout of MutM affected only the spectrum of mutations but did not change mutation frequency. Dps is known to protect DNA from oxidative damage. We found that dps-defective P. putida cells were more sensitive to sudden exposure to hydrogen peroxide than wild-type cells. At the same time, the absence of Dps did not affect the accumulation of mutations in populations of starved bacteria. Thus, it is possible that the protective role of Dps becomes essential for genome integrity only when bacteria are exposed to exogenous agents that lead to oxidative DNA damage but not under physiological conditions. Introduction of the Y family DNA polymerase PolV homologue rulAB into P. putida increased the proportion of A-to-C and A-to-G base substitutions among mutations, which occurred under starvation conditions. Since PolV is known to perform translesion synthesis past damaged bases in DNA (e.g., some oxidized forms of adenine), our results may imply that adenine oxidation products are also an important source of mutation in starving bacteria.


2018 ◽  
Vol 90 (2) ◽  
pp. 13-15 ◽  
Author(s):  
Jacek Kabzinski ◽  
Anna Walczak ◽  
Adam Dziki ◽  
Michał Mik ◽  
Ireneusz Majsterek

As a result of reactive oxygen species operation, cell damage occurs in both cellular organelles and molecules, including DNA. Oxidative damage within the genetic material can lead to accumulation of mutations and consequently to cancer transformation. OGG1 glycosylase, a component of the Base Excision Repair (BER) system, is one of the enzymes that prevents excessive accumulation of 8-oxoguanine (8-oxG), the most common compound formed by oxidative DNA damage. In case of structural changes of OGG1 resulting from polymorphic variants, we can observe a significant increase in the concentration of 8-oxG. Linking individual polymorphisms to DNA repair systems with increased risk of colorectal cancer will allow patients to be classified as high risk and included in a prophylactic program. The aim of the study was to determine the level of oxidative DNA damage and to analyze the distribution of Ser326Cys polymorphism of the OGG1 gene in a group of patients with colorectal cancer and in a control group in the Polish population. Material and methodology. DNA was isolated from the blood of 174 patients with colorectal cancer. The control group consisted of 176 healthy individuals. The level of oxidative damage was determined by analyzing the amount of 8-oxguanine using the HT 8-oxo-dG ELISA II Kit. Genotyping was performed via the TaqMan method. Results. The obtained results indicate that Ser326Cys polymorphism of the OGG1 gene increases the risk of RJG and is associated with significantly increased levels of 8-oxoguanine. Conclusions. Based on the results obtained, we conclude that Ser326Cys polymorphism of the OGG1 gene may modulate the risk of colorectal cancer by increasing the level of oxidative DNA damage.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2413-2413
Author(s):  
Wei Du ◽  
Reena Rani ◽  
Jared Sipple ◽  
Jonathan Schick ◽  
Qishen Pang

Abstract Abstract 2413 Oxidative stress has been implicated in the pathogenesis of many human diseases including Fanconi anemia (FA), a genetic disorder associated with bone marrow failure and progression to leukemia and other cancers. Here we show that several major anti-oxidant defense genes, including Glutathione peroxidase 1, Peroxiredoxin 3, Thioredoxin reductase 1, Superoxide dismutases 1, NAD(P)H:quinone oxireductase and Catalase, are down-regulated in bone marrow cells of FA patients. This gene down-regulation is selectively associated with increased oxidative DNA damage in the promoters of these anti-oxidant defense genes. Further, we show that both increased initial damage and reduced repair rate contribute to augmented oxidative DNA damage in FA cells. Using cell-based assays to assess promoter activity and damage repair kinetics, we demonstrate that FA proteins function to protect the promoter DNA from oxidative damage. Mechanistically, FA proteins appeared to act in concert with Brg1, a chromatin-remodeling ATPase subunit of the BAF complex. Specifically, Brg1 binds to the promoters of the anti-oxidant defense genes in steady state. Upon challenge with oxidative stress, FANCA and FANCD2 proteins are recruited to the promoter DNA, which correlates with significant increase in the binding of Brg1 within the promoter regions. Intriguingly, the formation of the FA-Brg1-promoter complex results in a marked decrease in nuclease hypersensitivity and oxidative damage in the promoter DNA in normal cells compared to FA cells. Finally, disassociation of the FA proteins from the Brg1-promoter complex parallels Pol II loading, suggesting a regulatory role for the FA proteins in transcription. Taken together, the study identifies a role of FA proteins in protecting anti-oxidant genes from oxidative damage. Disclosures: No relevant conflicts of interest to declare.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Zhong-Jie Liu ◽  
Wei Zhao ◽  
Qing-Guo Zhang ◽  
Le Li ◽  
Lu-Ying Lai ◽  
...  

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


2017 ◽  
Author(s):  
Anna R Poetsch ◽  
Simon J Boulton ◽  
Nicholas M Luscombe

AbstractDNA is subject to constant chemical modification and damage, which eventually results in variable mutation rates throughout the genome. Although detailed molecular mechanisms of DNA damage and repair are well-understood, damage impact and execution of repair across a genome remains poorly defined. To bridge the gap between our understanding of DNA repair and mutation distributions we developed a novel method, AP-seq, capable of mapping apurinic sitesand 8-oxo-7,8-dihydroguanine bases at ∼300bp resolution on a genome-wide scale. We directly demonstrate that the accumulation rate of oxidative damage varies widely across the genome, with hot spots acquiring many times more damage than cold spots. Unlike SNVs in cancers, damage burden correlates with marks for open chromatin notably H3K9ac and H3K4me2. Oxidative damage is also highly enriched in transposable elements and other repetitive sequences. In contrast, we observe decreased damage at promoters, exons and termination sites, but not introns, in a seemingly transcription-independent manner. Leveraging cancer genomic data, we also find locally reduced SNV rates in promoters, genes and other functional elements. Taken together, our study reveals that oxidative DNA damage accumulation and repair differ strongly across the genome, but culminate in a previously unappreciated mechanism that safe-guards the regulatory sequences and the coding regions of genes from mutations.


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