248. Oxidative stress and DNA damage in human spermatozoa

2008 ◽  
Vol 20 (9) ◽  
pp. 48
Author(s):  
G. N. De Iuliis ◽  
J. M. Finnie ◽  
R. J. Aitken
Keyword(s):  
Oxidative Stress ◽  
Mass Spectrometry ◽  
Dna Damage ◽  
Metal Ions ◽  
Electromagnetic Radiation ◽  
Germ Line ◽  
Human Spermatozoa ◽  
Ros Production ◽  
Male Germ Line ◽  
Catechol Estrogens

Unusually high levels of DNA damage in the male germ line are, unfortunately, characteristic of our species. A great deal of circumstantial evidence has linked DNA damage in human spermatozoa with adverse reproductive outcomes including reduced fertility and high rates of miscarriage. Although oxidative stress is thought to make a significant contribution to DNA damage in the male germ line, the mechanisms responsible for creating this stress have not yet been elucidated. We have undertaken a detailed analysis of the ability of estrogens, electromagnetic radiation and xenobiotics including metal ions to trigger reactive oxygen species (ROS) production and/or DNA damage in human spermatozoa in vitro. This investigation was completed using a range of techniques validated for use in these highly specialised cells. DNA integrity was assessed using the Comet and TUNEL assays, oxidative DNA adducts were detected by an anti-8-oxo-dG assay and cross-linking adducts were characterised by mass spectrometry. Intracellular redox activity was monitored using dihydroethidium as the probe. Of the factors evaluated, catechol estrogens, certain transition metal ions, radio frequency electromagnetic radiation and heat were all capable of stimulating ROS production in human spermatozoa. The oxidative stress created by exposure to such factors lead to the induction of significant DNA damage. Generally, redox inert compounds including non-catechol estrogens and xenobiotics such as phthalate esters did not lead to ROS production or measurable DNA damage. Mass spectrometry also indicated that catechol estrogens were capable of forming dimers that can cross-link the densely packed DNA strands in sperm chromatin. These findings raise fundamental questions about the importance of xenobiotics, environmental factors as well endogenous compounds in creating oxidative stress and DNA damage in the male germ line.

scholarly journals 002.Human spermatozoa: fruits of creation, seed of doubt

2004 ◽  
Vol 16 (9) ◽  
pp. 2
Author(s):  
R. J. Aitken
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Dna Repair ◽  
Germ Cells ◽  
Oxidative Dna Damage ◽  
Germ Line ◽  
Early Embryo ◽  
Human Spermatozoa ◽  
Obstructive Azoospermia ◽  
Male Germ Line

Defective sperm function is the largest defined cause of human infertility, affecting one in twenty Australian males. Despite its prevalence, we are only just beginning to understand the underlying mechanisms. The past decade has seen two major advances in this field: (1) the discovery that Y chromosome deletions play a key role in the aetiology of non-obstructive azoospermia/oligozoospermia; and (2) recognition that oxidative stress can impact upon the functional competence of human spermatozoa through peroxidative damage to the sperm plasma membrane. Oxidative stress has also been found to disrupt the integrity of DNA in the male germ line and may represent an important mechanism by which environmental impacts on human health are mediated. Thus, paternal exposure to various toxicants (cigarette smoke, organic solvents, heavy metals) has been linked with oxidative DNA damage in spermatozoa and developmental defects, including cancer, in the F1 generation. The male germ line becomes particularly vulnerable to such factors during the post meiotic stages of differentiation. Pre-meiotic germ cells always have the option of undergoing apoptosis if DNA damage is severe. However, post meiotic germ cells have lost both the ability to mount an apoptotic response and the capacity for DNA repair. As a result, germ cells are particularly vulnerable to genotoxic agents during spermiogenesis and epididymal maturation. If the fertilizing capacity of the spermatozoa is retained following toxicant exposure, then DNA damage will be transferred to the zygote and must be repaired subsequently by the oocyte and/or early embryo. Aberrant DNA repair at this stage has the potential to create mutations that will compromise embryonic development and, ultimately, the normality of the offspring. Elucidating the causes of oxidative damage in spermatozoa should help resolve the aetiology of conditions such as male infertility, early pregnancy loss and childhood disease, including cancer.

Oxidative stress and male reproductive biology

2004 ◽  
Vol 16 (5) ◽  
pp. 581 ◽  
Author(s):  
R. John Aitken ◽  
Mark A. Baker
Keyword(s):  
Oxidative Stress ◽  
Pregnancy Loss ◽  
Germ Line ◽  
Mammalian Species ◽  
Human Spermatozoa ◽  
Redox Activity ◽  
Cell Type ◽  
Male Germ Line ◽  
Cellular Redox ◽  
Improved Methods

Spermatozoa were the first cell type in which the cellular generation of reactive oxygen was demonstrated. This activity has now been confirmed in spermatozoa from all mammalian species examined including the rat, mouse, rabbit, horse, bull and human being. Under physiological circumstances, cellular redox activity is thought to drive the cAMP-mediated, tyrosine phosphorylation events associated with sperm capacitation. In addition to this biological role, human spermatozoa also appear to suffer from oxidative stress, with impacts on the normality of their function and the integrity of their nuclear and mitochondrial DNA. Recent studies have helped to clarify the molecular basis for the intense redox activity observed in defective human spermatozoa, the nature of the subcellular structures responsible for this activity and possible mechanisms by which oxidative stress impacts on these cells. Given the importance of oxidative damage in the male germ line to the origins of male infertility, early pregnancy loss and childhood disease, this area of sperm biochemistry deserves attention from all those interested in improved methods for the diagnosis, management and prevention of male-mediated reproductive failure.

scholarly journals Heat exposure induces oxidative stress and DNA damage in the male germ line†

2018 ◽  
Vol 98 (4) ◽  
pp. 593-606 ◽  
Author(s):  
Brendan J Houston ◽  
Brett Nixon ◽  
Jacinta H Martin ◽  
Geoffry N De Iuliis ◽  
Natalie A Trigg ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Germ Line ◽  
Heat Exposure ◽  
Male Germ Line

Paternal impacts on development: identification of genomic regions vulnerable to oxidative DNA damage in human spermatozoa

2019 ◽  
Vol 34 (10) ◽  
pp. 1876-1890 ◽  
Author(s):  
M J Xavier ◽  
B Nixon ◽  
S D Roman ◽  
R J Scott ◽  
J R Drevet ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Male Infertility ◽  
Oxidative Damage ◽  
Oxidative Dna Damage ◽  
Human Spermatozoa ◽  
Research Centre ◽  
Environmental Toxicants ◽  
Next Generation ◽  
Genomic Regions

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.

scholarly journals Serine-70 phosphorylated Bcl-2 prevents oxidative stress-induced DNA damage by modulating the mitochondrial redox metabolism

2020 ◽  
Vol 48 (22) ◽  
pp. 12727-12745 ◽  
Author(s):  
Stephen Jun Fei Chong ◽  
Kartini Iskandar ◽  
Jolin Xiao Hui Lai ◽  
Jianhua Qu ◽  
Deepika Raman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Cell Death ◽  
Cell Lines ◽  
Ros Production ◽  
Primary Cells ◽  
Mitochondrial Complex ◽  
Drug Induced ◽  
Complex Iv ◽  
Redox Sensor

Abstract Bcl-2 phosphorylation at serine-70 (S70pBcl2) confers resistance against drug-induced apoptosis. Nevertheless, its specific mechanism in driving drug-resistance remains unclear. We present evidence that S70pBcl2 promotes cancer cell survival by acting as a redox sensor and modulator to prevent oxidative stress-induced DNA damage and execution. Increased S70pBcl2 levels are inversely correlated with DNA damage in chronic lymphocytic leukemia (CLL) and lymphoma patient-derived primary cells as well as in reactive oxygen species (ROS)- or chemotherapeutic drug-treated cell lines. Bioinformatic analyses suggest that S70pBcl2 is associated with lower median overall survival in lymphoma patients. Empirically, sustained expression of the redox-sensitive S70pBcl2 prevents oxidative stress-induced DNA damage and cell death by suppressing mitochondrial ROS production. Using cell lines and lymphoma primary cells, we further demonstrate that S70pBcl2 reduces the interaction of Bcl-2 with the mitochondrial complex-IV subunit-5A, thereby reducing mitochondrial complex-IV activity, respiration and ROS production. Notably, targeting S70pBcl2 with the phosphatase activator, FTY720, is accompanied by an enhanced drug-induced DNA damage and cell death in CLL primary cells. Collectively, we provide a novel facet of the anti-apoptotic Bcl-2 by demonstrating that its phosphorylation at serine-70 functions as a redox sensor to prevent drug-induced oxidative stress-mediated DNA damage and execution with potential therapeutic implications.

scholarly journals Keratinocyte Growth Factor 2 Ameliorates UVB-Induced Skin Damage via Activating the AhR/Nrf2 Signaling Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Shuang Gao ◽  
Keke Guo ◽  
Yu Chen ◽  
Jungang Zhao ◽  
Rongrong Jing ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Growth Factor ◽  
Mitochondrial Dysfunction ◽  
Signaling Pathway ◽  
Keratinocyte Growth Factor ◽  
Ros Production ◽  
Skin Damage ◽  
Nrf2 Signaling Pathway ◽  
Uvb Exposure

Objective: Exposure to ultraviolet B (UVB) can cause skin damage through oxidative stress, DNA damage, and apoptosis. Keratinocyte growth factor (KGF) has been shown to reduce the content of intracellular reactive oxygen species (ROS) following UVB exposure, a role that is crucial for the efficient photoprotection of skin. The present study evaluated the photoprotective effect of KGF-2 on UVB-induced skin damage and explored its potential molecular mechanism.Methods: To evaluate the effect of KGF-2 on UVB-induced damage ex vivo, a human epidermal full-thickness skin equivalent was pretreated without or with KGF-2 and then exposed to UVB and the levels of histopathological changes, DNA damage, inflammation, and apoptosis were then evaluated. The ability of KGF-2 to protect the cells against UVB-inflicted damage and its effect on ROS production, apoptosis, and mitochondrial dysfunction were determined in HaCaT cells.Results: Pretreatment of the epidermis with KGF-2 ameliorated the extent of photodamage. At the cellular level, KGF-2 could attenuate ROS production, apoptosis, DNA damage, and mitochondrial dysfunction caused by UVB exposure. KGF-2 could also activate the aryl hydrocarbon receptor (AhR) to trigger the Nrf2 signaling pathway.Conclusion: Taken together, our findings suggested that KGF-2 could ameliorate UVB-induced skin damage through inhibiting apoptosis, reducing oxidative stress, and preventing DNA damage and mitochondrial dysfunction via regulating AhR/Nrf2 signaling pathway.

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