Phosphoinositide 3-kinase signalling pathway involvement in a truncated apoptotic cascade associated with motility loss and oxidative DNA damage in human spermatozoa

2011 ◽  
Vol 436 (3) ◽  
pp. 687-698 ◽  
Author(s):  
Adam J. Koppers ◽  
Lisa A. Mitchell ◽  
Ping Wang ◽  
Minjie Lin ◽  
R. John Aitken
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Sperm Quality ◽  
Reactive Oxygen Species Generation ◽  
Annexin V ◽  
Sperm Nucleus ◽  
Human Spermatozoa ◽  
Direct Result ◽  
Phosphoinositide 3 Kinase ◽  
Apoptotic Cascade

Human spermatozoa are characterized by poor functionality and abundant DNA damage that collude to generate the high incidences of male infertility and miscarriage seen in our species. Although apoptosis has been suggested as a possible cause of poor sperm quality, the ability of these cells to enter an apoptotic state and the factors that might trigger such an event are unresolved. In the present study we provide evidence that the commitment of these cells to apoptosis is negatively regulated by PI3K (phosphoinositide 3-kinase)/AKT. If PI3K activity is inhibited, then spermatozoa default to an apoptotic cascade characterized by rapid motility loss, mitochondrial reactive oxygen species generation, caspase activation in the cytosol, annexin V binding to the cell surface, cytoplasmic vacuolization and oxidative DNA damage. However, the specialized physical architecture of spermatozoa subsequently prevents endonucleases activated during this process from penetrating the sperm nucleus and cleaving the DNA. As a result, DNA fragmentation does not occur as a direct result of apoptosis in spermatozoa as it does in somatic cells, even though oxidative DNA adducts can clearly be detected. We propose that this unusual truncated apoptotic cascade prepares spermatozoa for silent phagocytosis within the female tract and prevents DNA-damaged spermatozoa from participating in fertilization.

001. ORIGINS OF DNA DAMAGE IN SPERMATOZOA

2010 ◽  
Vol 22 (9) ◽  
pp. 1
Author(s):  
R. J. Aitken
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Sperm Nucleus ◽  
Human Spermatozoa ◽  
Environmental Toxicants ◽  
Apoptotic Pathway ◽  
Systemic Oxidative Stress ◽  
Risk Of Disease ◽  
Dna Strand

DNA damage is frequently encountered in the spermatozoa of sub-fertile male mammals and is correlated with a range of adverse clinical outcomes including impaired fertilization, disrupted embryonic development, increased rates of miscarriage and an enhanced risk of disease in the progeny. The etiology of DNA fragmentation in human spermatozoa is closely correlated with the appearance of oxidative base adducts and evidence of impaired chromatin remodelling during spermiogenesis. In light of these associations we propose a two step hypothesis for the origins of DNA damage in spermatozoa. In Step 1, a variety of intrinsic (diabetes, varicocele, testicular torsion, obesity) and extrinsic (radiofrequency electromagnetic radiation, heat, cigarette smoke, diet, environmental toxicants) factors collude to generate a state of oxidative stress in the testes. This stress impedes spermiogenesis resulting in the generation of spermatozoa with poorly remodelled chromatin. These defective cells readily default to an apoptotic pathway comprising motility loss, caspase activation, phosphatidylserine exteriorization and the production of reactive oxygen species (ROS) by the mitochondria. In Step 2, these mitochondrial ROS attack the spermatozoa inducing lipid peroxidation and oxidative DNA damage, which then leads to DNA strand breakage and cell death. Nucleases activated and released during the apoptotic process are denied access to the sperm nucleus because the unique physical architecture of this cell prevents it. For this reason, a majority of the DNA damage encountered in human spermatozoa is oxidative. Given the importance of oxidative stress in the etiology of DNA damage, there should be a significant therapeutic role for antioxidants in the treatment of this condition. Furthermore, if oxidative DNA damage in spermatozoa is providing a sensitive readout of systemic oxidative stress, the implications of these findings could stretch beyond our immediate goal of trying to minimize DNA damage in spermatozoa as a prelude to assisted conception therapy.

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 Improved methods of DNA extraction from human spermatozoa that mitigate experimentally-induced oxidative DNA damage

PLoS ONE ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. e0195003 ◽  
Author(s):  
Miguel J. Xavier ◽  
Brett Nixon ◽  
Shaun D. Roman ◽  
Robert John Aitken
Keyword(s):  
Dna Damage ◽  
Dna Extraction ◽  
Oxidative Dna Damage ◽  
Human Spermatozoa ◽  
Improved Methods ◽  
Experimentally Induced

scholarly journals Nuclear Integrity but Not Topology of Mouse Sperm Chromosome is Affected by Oxidative DNA Damage

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 501 ◽  
Author(s):  
Alexandre Champroux ◽  
Christelle Damon-Soubeyrand ◽  
Chantal Goubely ◽  
Stephanie Bravard ◽  
Joelle Henry-Berger ◽  
...  
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Sperm Nucleus ◽  
Sperm Chromatin ◽  
Sperm Dna Fragmentation ◽  
Chromosome 2 ◽  
Mouse Sperm ◽  
Sperm Dna Damage ◽  
Chromosome Architecture ◽  
Sperm Dna

Recent studies have revealed a well-defined higher order of chromosome architecture, named chromosome territories, in the human sperm nuclei. The purpose of this work was, first, to investigate the topology of a selected number of chromosomes in murine sperm; second, to evaluate whether sperm DNA damage has any consequence on chromosome architecture. Using fluorescence in situ hybridization, confocal microscopy, and 3D-reconstruction approaches we demonstrate that chromosome positioning in the mouse sperm nucleus is not random. Some chromosomes tend to occupy preferentially discrete positions, while others, such as chromosome 2 in the mouse sperm nucleus are less defined. Using a mouse transgenic model (Gpx5−/−) of sperm nuclear oxidation, we show that oxidative DNA damage does not disrupt chromosome organization. However, when looking at specific nuclear 3D-parameters, we observed that they were significantly affected in the transgenic sperm, compared to the wild-type. Mild reductive DNA challenge confirmed the fragility of the organization of the oxidized sperm nucleus, which may have unforeseen consequences during post-fertilization events. These data suggest that in addition to the sperm DNA fragmentation, which is already known to modify sperm nucleus organization, the more frequent and, to date, the less highly-regarded phenomenon of sperm DNA oxidation also affects sperm chromatin packaging.

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.

Founders' Lecture. Human spermatozoa: fruits of creation, seeds of doubt

2004 ◽  
Vol 16 (7) ◽  
pp. 655 ◽  
Author(s):  
R. John Aitken
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Unsaturated Fatty Acids ◽  
Selective Vulnerability ◽  
Human Spermatozoa ◽  
Biochemical Basis ◽  
Sperm Plasma Membrane ◽  
Genital Tract Infections ◽  
Tract Infections

Deoxyribonucleic acid damage in the male germline is associated with defective fertilisation, impaired embryonic development, reduced implantation, abortion and childhood disease. Oxidative stress and the retention of excess residual cytoplasm by the spermatozoa are frequently associated with the induction of such damage. The redox cycling of xenobiotics by oxido-reductases in the germline, the patient’s age, the incidence of genital tract infections and Sertoli cell dysfunction are all possible contributors to DNA damage in germ cells. Collateral peroxidation of unsaturated fatty acids in the sperm plasma membrane generally ensures that spermatozoa experiencing severe oxidative DNA damage cannot participate in the process of fertilisation. The adaptive termination of pregnancy through the selective vulnerability of genes involved in placentation may also help prevent the vertical transmission of damaged DNA. However, the ultimate safeguard against this form of damage will be to understand the biochemical basis of oxidative stress in human spermatozoa, so that the underlying causative mechanisms can be addressed in a logical manner.

A High Resolution Cytochemical Study of Nuclear ATPase in Human Spermatozoa

1975 ◽  
Vol 33 ◽  
pp. 594-595
Author(s):  
A. Sosa ◽  
L. Calzada
Keyword(s):  
High Resolution ◽  
Atpase Activity ◽  
Nuclear Membrane ◽  
Human Sperm ◽  
Sperm Nucleus ◽  
Human Spermatozoa ◽  
Cytochemical Study ◽  
Membrane Bound ◽  
Sperm Nuclei ◽  
Interchromatin Space

The dependence of nuclear metabolism on the function of the nuclear membrane is not well understood. Whether or not the function of the nuclear membrane is partial or totally responsible of the repressed template activity of human sperm nucleus has not at present been elucidated. One of the membrane-bound enzymatic activities which is concerned with the mechanisms whereby substances are thought to cross cell membranes is adenosintriphosphatase (ATPase). This prompted its characterization and distribution by high resolution photogrammetry on isolated human sperm nuclei. Isolated human spermatozoa nuclei were obtained as previously described. ATPase activity was demonstrated by the method of Wachstein and Meisel modified by Marchesi and Palade. ATPase activity was identified as dense and irregularly distributed granules confined to the internal leaflet of the nuclear membrane. Within the nucleus the appearance of the reaction product occurs as homogenous and dense precipitates in the interchromatin space.

Acrylamide Exposure and Oxidative DNA Damage, Lipid Peroxidation and Fasting Plasma Glucose Alteration: Association and Mediation Analyses in Chinese Urban Adults

2020 ◽  
Author(s):  
Bin Wang ◽  
Weihong Qiu ◽  
Shijie Yang ◽  
Limin Cao ◽  
Chunmei Zhu ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Dna Damage ◽  
Plasma Glucose ◽  
Fasting Plasma Glucose ◽  
Oxidative Dna Damage ◽  
Adult Population ◽  
Prostaglandin F2α ◽  
Mediation Analyses ◽  
Mediating Role ◽  
Fasting Plasma

<a><b>OBJECTIVE: </b></a>Acrylamide exposure from daily-consumed food has raised global concern.<b> </b>We aimed to assess the exposure-response relationships of internal acrylamide exposure with oxidative DNA damage, lipid peroxidation and fasting plasma glucose (FPG) alteration, and investigate the mediating role of oxidative DNA damage and lipid peroxidation in the association of internal acrylamide exposure with FPG. <p><b>RESEARCH DESIGN AND METHODS:</b> FPG and urinary biomarkers of oxidative DNA damage (8-hydroxy-deoxy-guanosine, 8-OHdG), lipid peroxidation (8-iso-prostaglandin-F2α, 8-iso-PGF2α) and acrylamide exposure (N-acetyl-S-(2-carbamoylethyl)-L-cysteine, AAMA; N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine, GAMA) were measured for 3,270 general adults from the Wuhan-Zhuhai cohort. The associations of urinary acrylamide metabolites with 8-OHdG, 8-iso-PGF2α and FPG were assessed by linear mixed models. The mediating roles of 8-OHdG and 8-iso-PGF2α were evaluated by mediation analysis.</p> <p><b>RESULTS:</b> We found significant linear positive dose-response relationships of urinary acrylamide metabolites with 8-OHdG, 8-iso-PGF2α and FPG (except GAMA with FPG), and 8-iso-PGF2α with FPG. Each 1-unit increase in log-transformed level of AAMA, ΣUAAM (AAMA+GAMA) or 8-iso-PGF2α was associated with a 0.17-, 0.15- or 0.23-mmol/L increase in FPG, respectively (<i>P </i>or/and<i> P trend</i><0.05). Each 1% increase in AAMA, GAMA or ΣUAAM was associated with a 0.19%, 0.27% or 0.22% increase in 8-OHdG, respectively, and a 0.40%, 0.48% or 0.44% increase in 8-iso-PGF2α, respectively (<i>P </i>and<i> P trend</i><0.05). Increased 8-iso-PGF2α rather than 8-OHdG significantly mediated 64.29% and 76.92% of the AAMA and ΣUAAM associated-FPG increases, respectively.</p> <p><b>CONCLUSIONS:</b> Exposure of general adult population to acrylamide was associated with FPG elevation, oxidative DNA damage and lipid peroxidation, which in turn partly mediated acrylamide-associated FPG elevation.<b></b></p>

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