Sperm Epigenome Research Articles

Polycomb protein SCML2 mediates paternal epigenetic inheritance through sperm chromatin.

Sperm chromatin retains small amounts of histones, and chromatin states of sperm mirror gene expression programs of the next generation. However, it remains largely unknown how paternal epigenetic information is transmitted through sperm chromatin. Here, we present a novel mouse model of paternal epigenetic inheritance, in which deposition of Polycomb repressive complex 2 (PRC2) mediated-repressive H3K27me3 is attenuated in the paternal germline. By applying modified methods of assisted reproductive technology using testicular sperm, we rescued infertility of mice missing Polycomb protein SCML2, which regulates germline gene expression by establishing H3K27me3 on bivalent promoters with other active marks H3K4me2/3. We profiled epigenomic states (H3K27me3 and H3K4me3) of testicular sperm and epididymal sperm, demonstrating that the epididymal pattern of the sperm epigenome is already established in testicular sperm and that SCML2 is required for this process. In F1 males of X-linked Scml2-knockout mice, which have a wild-type genotype, gene expression is dysregulated in the male germline during spermiogenesis. These dysregulated genes are targets of SCML2-mediated H3K27me3 in F0 sperm. Further, dysregulation of gene expression was observed in the mutant-derived wild-typeF1 preimplantation embryos. Together, we present functional evidence that the classic epigenetic regulator Polycomb mediates paternal epigenetic inheritance through sperm chromatin.

CpG DNA methylation changes during epididymal sperm maturation in bulls

BackgroundDuring epididymal transit spermatozoa acquire specific morphological features which enhance their ability to swim in a progressive manner and interact with the oocytes. At the same time, sperm cells undergo specific molecular rearrangements essential for the fertilizing sperm to drive a correct embryo development. To assess epigenetic sperm changes during epididymal maturation, the caput, corpus and cauda epididymis sperm tracts were isolated from eight bulls and characterized for different sperm quality parameters and for CpG DNA methylation using Reduced Representation Bisulfite Sequencing (RRBS) able to identify differentially methylated regions (DMRs) in higher CpG density regions.ResultsCaput sperm showed significant variation in motility and sperm kinetics variables, whereas spermatozoa collected from the corpus presented morphology variation and significant alterations in variables related to acrosome integrity. A total of 57,583 methylated regions were identified across the eight bulls, showing a significantly diverse distribution for sperm collected in the three epididymal regions. Differential methylation was observed between caput vs corpus (n = 11,434), corpus vs cauda (n = 12,372) and caput vs cauda (n = 2790). During epididymal transit a high proportion of the epigenome was remodeled, showing several regions in which methylation decreases from caput to corpus and increases from corpus to cauda.ConclusionsSpecific CpG DNA methylation changes in sperm isolated from the caput, corpus, and cauda epididymis tracts are likely to refine the sperm epigenome during sperm maturation, potentially impacting sperm fertilization ability and spatial organization of the genome during early embryo development.

Epigenetic changes in sperm are associated with paternal and child quantitative autistic traits in an autism-enriched cohort.

There is a need to consider paternal contributions to autism spectrum disorder (ASD) more strongly. Autism etiology is complex, and heritability is not explained by genetics alone. Understanding paternal gametic epigenetic contributions to autism could help fill this knowledge gap. In the present study, we explored whether paternal autistic traits, and the sperm epigenome, were associated with autistic traits in children at 36 months enrolled in the Early Autism Risk Longitudinal Investigation (EARLI) cohort. EARLI is a pregnancy cohort that recruited and enrolled pregnant women in the first half of pregnancy who already had a child with ASD. After maternal enrollment, EARLI fathers were approached and asked to provide a semen specimen. Participants were included in the present study if they had genotyping, sperm methylation data, and Social Responsiveness Scale (SRS) score data available. Using the CHARM array, we performed genome-scale methylation analyses on DNA from semen samples contributed by EARLI fathers. The SRS-a 65-item questionnaire measuring social communication deficits on a quantitative scale-was used to evaluate autistic traits in EARLI fathers (n = 45) and children (n = 31). We identified 94 significant child SRS-associated differentially methylated regions (DMRs), and 14 significant paternal SRS-associated DMRs (fwer p < 0.05). Many child SRS-associated DMRs were annotated to genes implicated in ASD and neurodevelopment. Six DMRs overlapped across the two outcomes (fwer p < 0.1), and, 16 DMRs overlapped with previous child autistic trait findings at 12 months of age (fwer p < 0.05). Child SRS-associated DMRs contained CpG sites independently found to be differentially methylated in postmortem brains of individuals with and without autism. These findings suggest paternal germline methylation is associated with autistic traits in 3-year-old offspring. These prospective results for autism-associated traits, in a cohort with a family history of ASD, highlight the potential importance of sperm epigenetic mechanisms in autism.

MP01-06 DELTA-9-TETRAHYDROCANNABINOL USE ALTERS SPERM DNA METHYLATION IN RHESUS MACAQUES

You have accessJournal of UrologyCME1 Apr 2023MP01-06 DELTA-9-TETRAHYDROCANNABINOL USE ALTERS SPERM DNA METHYLATION IN RHESUS MACAQUES Jason Hedges, Lyndsey Shorey-Kendrick, Carol Hanna, Jasper Bash, Eliot Spindel, Charles Easley, Susan Murphy, and Jamie Lo Jason HedgesJason Hedges More articles by this author , Lyndsey Shorey-KendrickLyndsey Shorey-Kendrick More articles by this author , Carol HannaCarol Hanna More articles by this author , Jasper BashJasper Bash More articles by this author , Eliot SpindelEliot Spindel More articles by this author , Charles EasleyCharles Easley More articles by this author , Susan MurphySusan Murphy More articles by this author , and Jamie LoJamie Lo More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003212.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Cannabis is the most commonly used drug by reproductive age males. Our objective was to determine the effect of chronic delta-9-tetrahydrocannabinol (THC) use on the sperm epigenome and whether these changes are permanent or temporary with discontinuation of THC in a rhesus macaque (RM) model. METHODS: We performed whole genome bisulfite sequencing (WGBS) of DNA extracted from sperm collected from 6 adult RM at baseline (pre-THC), at a high-THC dose (2.5 mg/7kg/day), and post-THC discontinuation for 140 days (∼2 spermatogenesis cycles). Bioinformatic analysis included QA/QC assessments, alignment to the rhesus reference genome, and identification of differentially methylated regions (DMRs). RESULTS: Overlap of genes annotated to DMRs in our RM following THC with published gene lists of human cannabis users and non-users was more than expected by chance (p=2.00e-82; Figure 1A). Pre-THC vs post-THC DMRs were similarly enriched for genes annotated to methylation differences between pre-cannabis exposure vs. post-cannabis discontinuation in humans (Figure 1B). Pre-THC vs high-THC DMRs annotated to 3,902 unique genes annotated and were significantly enriched for genes previously associated with autism spectrum disorder (ASD) (Figure 1C). We identified 2,759 DMRs between pre-THC and high-THC that intersected DMRs in high-THC vs post-THC sperm samples and demonstrated a reversal in methylation post-THC toward the level of methylation pre-THC (Figure 1D). A smaller number of DMRs between pre-THC and high-THC (n=1,898) did not return to baseline levels after THC abstinence (Figure 1E). Using Ingenuity Pathway Analysis, the top canonical pathway associated with THC and restored to baseline levels was the “synaptogenesis signaling pathway” and top biofunctions included “nervous system development and function” and “tissue development”. Similarly, the 1,898 non-restored DMRs were also enriched for genes in the “synaptogenesis signaling pathway” and “nervous system development and function”, as well as for genes in the “sperm motility” canonical pathway. CONCLUSIONS: Chronic THC use in RM alters genes related to nervous system development and function, and autism spectrum disorder that may impact longterm offspring outcomes. Discontinuation of THC resulted in restored methylation in only a subset of DMRs. Source of Funding: NICHD, NIDA, Silver Family © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e3 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jason Hedges More articles by this author Lyndsey Shorey-Kendrick More articles by this author Carol Hanna More articles by this author Jasper Bash More articles by this author Eliot Spindel More articles by this author Charles Easley More articles by this author Susan Murphy More articles by this author Jamie Lo More articles by this author Expand All Advertisement PDF downloadLoading ...

Cessation of chronic delta-9-tetrahydrocannabinol use partially reverses impacts on male fertility and the sperm epigenome in rhesus macaques

To determine whether discontinuation of delta-9-tetrahydrocannabinol (THC) use mitigates THC-associated changes in male reproductive health using a rhesus macaque model of daily THC edible consumption. Research animal study. Research institute environment. Adult male rhesus macaques (age, 8-10 years; n = 6). Chronic daily THC edible administration at medically and recreationally relevant contemporary doses followed by cessation of THC use. Testicular volume, serum male hormones, semen parameters, sperm deoxyribonucleic acid (DNA) fragmentation, seminal fluid proteomics, and whole genome bisulfite sequencing of sperm DNA. Chronic THC use resulted in significant testicular atrophy, increased gonadotropin levels, decreased serum sex steroid levels, changes in seminal fluid proteome, and increased DNA fragmentation with partial recovery after discontinuation of THC use. For every increase of 1 mg/7 kg/day in THC dosing, there was a significant decrease in the total testicular volume bilaterally by 12.6 cm3 (95% confidence interval [CI], 10.6-14.5), resulting in a 59% decrease in volume. With THC abstinence, the total testicular volume increased to 73% of its original volume. Similarly, with THC exposure, there were significant decreases in the mean total testosterone and estradiol levels and a significant increase in the follicle-stimulating hormone level. With increasing THC dose, there was a significant decrease in the liquid semen ejaculate volume and weight of coagulum; however, no other significant changes in the other semen parameters were noted. After discontinuing THC use, there was a significant increase in the total serum testosterone level by 1.3 ng/mL (95% CI, 0.1-2.4) and estradiol level by 2.9 pg/mL (95% CI, 0.4-5.4), and the follicle-stimulating hormone level significantly decreased by 0.06 ng/mL (95% CI, 0.01-0.11). Seminal fluid proteome analysis revealed differential expression of proteins enriched for processes related to cellular secretion, immune response, and fibrinolysis. Whole genome bisulfite sequencing identified 23,558 CpGs differentially methylated in heavy-THC vs. pre-THC sperm, with partial restoration of methylation after discontinuation of THC use. Genes associated with altered differentially methylated regions were enriched for those involved in the development and function of the nervous system. This is the first study demonstrating that discontinuation of chronic THC use in rhesus macaques partially restores adverse impacts to male reproductive health, THC-associated sperm differentially methylated regions in genes important for development, and expression of proteins important for male fertility.

Age-related methylation changes in the human sperm epigenome.

Advanced paternal age is associated with increased risks for reproductive and offspring medical problems. Accumulating evidence suggests age-related changes in the sperm epigenome as one underlying mechanism. Using reduced representation bisulfite sequencing on 73 sperm samples of males attending a fertility center, we identified 1,162 (74%) regions which were significantly (FDR-adjusted) hypomethylated and 403 regions (26%) being hypermethylated with age. There were no significant correlations with paternal BMI, semen quality, or ART outcome. The majority (1,152 of 1,565; 74%) of age-related differentially methylated regions (ageDMRs) were located within genic regions, including 1,002 genes with symbols. Hypomethylated ageDMRs were closer to transcription start sites than hypermethylated DMRs, half of which reside in gene-distal regions. In this and conceptually related genome-wide studies, so far 2,355 genes have been reported with significant sperm ageDMRs, however most (90%) of them in only one study. The 241 genes which have been replicated at least once showed significant functional enrichments in 41 biological processes associated with development and the nervous system and in 10 cellular components associated with synapses and neurons. This supports the hypothesis that paternal age effects on the sperm methylome affect offspring behaviour and neurodevelopment. It is interesting to note that sperm ageDMRs were not randomly distributed throughout the human genome; chromosome 19 showed a highly significant twofold enrichment with sperm ageDMRs. Although the high gene density and CpG content have been conserved, the orthologous marmoset chromosome 22 did not appear to exhibit an increased regulatory potential by age-related DNA methylation changes.

Epigenetics Role in Spermatozoa Function: Implications in Health and Evolution—An Overview

The unique properties of spermatozoa are established through the spermatogenesis and maturation processes concurrently with its epigenome. It is known that damage to epigenetic mechanisms can lead to reproductive problems. However, scientific reviews addressing the role of the spermatozoa epigenome during the reproductive process are scarce. Therefore, the aim of this review was to offer a detailed overview of current knowledge in the field of spermatozoa epigenetics and its consequent implications. A full search was performed through three databases by combining five keywords. Inclusion criteria were implemented to grant accessibility, relevance, and concretion. Besides, some articles were manually removed or added to obtain an adequate and complete collection of 485 scientific publications. This compilation was used to conduct the bibliometric analysis and the data review separately. Bibliometric results displayed that spermatozoa epigenetics is an active and growing research area. The bibliographic overview showed that sperm epigenome correlates with the development of its function, explaining the environmental influence on reproductive pathologies or abnormal inheritance. The main conclusions were that the normal performance of sperm is heavily reliant on its epigenetics and that this study area is burgeoning, with the potential ability to provide society with clinical innovations in a short-term period.

Sperm DNA methylome abnormalities occur both pre- and post-treatment in men with Hodgkin disease and testicular cancer

BackgroundCombination chemotherapy has contributed to increased survival from Hodgkin disease (HD) and testicular cancer (TC). However, questions concerning the quality of spermatozoa after treatment have arisen. While studies have shown evidence of DNA damage and aneuploidy in spermatozoa years following anticancer treatment, the sperm epigenome has received little attention. Our objectives here were to determine the impact of HD and TC, as well as their treatments, on sperm DNA methylation. Semen samples were collected from community controls (CC) and from men undergoing treatment for HD or TC, both before initiation of chemotherapy and at multiple times post-treatment. Sperm DNA methylation was assessed using genome-wide and locus-specific approaches.ResultsImprinted gene methylation was not affected in the sperm of HD or TC men, before or after treatment. Prior to treatment, using Illumina HumanMethylation450 BeadChip (450 K) arrays, a subset of 500 probes was able to distinguish sperm samples from TC, HD and CC subjects; differences between groups persisted post-treatment. Comparing altered sperm methylation between HD or TC patients versus CC men, twice as many sites were affected in TC versus HD men; for both groups, the most affected CpGs were hypomethylated. For TC patients, the promoter region of GDF2 contained the largest region of differential methylation. To assess alterations in DNA methylation over time/post-chemotherapy, serial samples from individual patients were compared. With restriction landmark genome scanning and 450 K array analyses, some patients who underwent chemotherapy showed increased alterations in DNA methylation, up to 2 to 3 years post-treatment, when compared to the CC cohort. Similarly, a higher-resolution human sperm-specific assay that includes assessment of environmentally sensitive regions, or “dynamic sites,” also demonstrated persistently altered sperm DNA methylation in cancer patients post-treatment and suggested preferential susceptibility of “dynamic” CpG sites.ConclusionsDistinct sperm DNA methylation signatures were present pre-treatment in men with HD and TC and may help explain increases in birth defects reported in recent clinical studies. Epigenetic defects in spermatozoa of some cancer survivors were evident even up to 2 years post-treatment. Abnormalities in the sperm epigenome both pre- and post-chemotherapy may contribute to detrimental effects on future reproductive health.

The developmental miR-17–92 cluster and the Sfmbt2 miRNA cluster cannot rescue the abnormal embryonic development generated using obstructive epididymal environment-producing sperm in C57BL/6 J mice

BackgroundSperm, during epididymal transit, acquires microRNAs(miRNAs), which are crucial for embryonic development. However, whether sperm miRNAs influenced by an obstructive epididymal environment affect embryonic development remains unknown.MethodThe sham operation and vasectomy were performed in C57BL/6 J mice to create the control group (CON) and the obstructive epididymal environment group(OEE) group, respectively. The morphology of the testis and epididymis was observed using hematoxylin and eosin staining (HE staining) to establish the OEE mice model. The sperm quality test, intracytoplasmic sperm injection (ICSI), and epididymosomes fusion were employed to observe the effect of the obstructive epididymal environment on sperm and resultant embryonic development. The alteration of the sperm small RNA (sRNA) profile was analyzed by sRNA sequencing. RT-qPCR and DNA methylation were applied to observe the effect of obstructive epididymis on the expression of sperm miRNAs. The miRNAs microinjection was used to explore the impacts of sperm miRNAs on embryonic development.ResultsWe confirmed postoperative 8-week mice as the OEE mice model by examining the morphology of the testis and epididymis. In the OEE group, we observed that sperm quality degraded and the development potential of embryos was reduced, which can be saved by the normal epididymal environment. The sperm sRNA sequencing revealed that the expression of the developmental miR-17–92 cluster and the Sfmbt2 miRNA cluster was downregulated in the OEE group. The expression of these two miRNA clusters in epididymis was also downregulated and regulated by DNA methylation. However, the downregulation of either the miR-17–92 cluster or the Sfmbt2 miRNA cluster in normal zygotes did not impair embryonic development.ConclusionThe obstructive epididymal environment influences sperm quality and resultant embryonic development, as well as the abundance of the developmental miR-17–92 cluster and the Sfmbt2 miRNA cluster in sperm, but these miRNA clusters are not the cause of abnormal embryonic development. It implies that epididymis is important in early embryonic development and may play a potential role in sperm epigenome.

Paternal exposure to arsenic and sperm DNA methylation of imprinting gene Meg3 in reproductive-aged men.

Prenatal exposure to arsenic and mercury have been associated with adverse pregnancy outcomes that might be in part mediated by dynamic modification of imprinting gene that are emerging mechanism. The objective of this study was to examine the impacts of paternal exposure to arsenic and co-exposure to arsenic and mercury on human sperm DNA methylation status of imprinting genes, respectively. A total of 352 male subjects (23-52years old) were recruited and demographic data were obtained through questionnaires. Urinary arsenic and mercury levels were measured using hydride generation-atomic fluorescence spectrometer. Multivariate regression model was employed to investigate the relationship between urinary arsenic levels and sperm DNA methylation status at H19, Meg3 and Peg3, measured by pyrosequencing, and evaluating the interaction with mercury. After adjusting potential confounds factors by multivariate regression model, the results indicated a significantly positive relationship between urinary arsenic levels and the methylation status of Meg3 at both mean level (β = + 0.125, p < 0.001) and all individual CpGs, i.e., CpG1 (β = + 0.094, p < 0.001), CpG2 (β = + 0.132, p < 0.001), CpG3 (β = + 0.121, p < 0.001), CpG4 (β = + 0.142, p < 0.001), CpG5 (β = + 0.111, p < 0.001), CpG6 (β = + 0.120, p < 0.001), CpG7 (β = + 0.143, p < 0.001), CpG8 (β = + 0.139, p < 0.001) of Meg3 DMRs. The interaction effects analysis indicated the interaction effects of arsenic and mercury on Meg3 were not existing. Paternal nonoccupational exposure to arsenic induces the altered DNA methylation status of Meg3 in human sperm DNA. In addition, the interaction effects of arsenic and mercury on Meg3 were not existing. These findings would implicate the sensibility of sperm epigenome for environmental pollutions.

302 Implications of the Paternal Environment for Future Generations

Abstract The use of genetically superior males for artificial insemination has arguably been the most important tool to maximize the dissemination of desirable genes and improve the performance traits of agriculturally important species. The sire’s reproductive fitness traditionally focuses on breeding soundness, with the narrow assumption that role of the male is restricted to providing sperm to the oocyte, such that once fertilization occurs, the gestational outcome depends entirely on the dam. The sire’s role, however, extends beyond fertilization as the sperm epigenome mediates early embryo gene expression, thereby influencing subsequent embryo quality and developmental competence. Since the epigenome is sensitive to the environment, including nutrition, we used a rodent model of paternal exposures to test the hypothesis that multigenerational effects are transmitted through the paternal lineage. We also demonstrate that a possible mechanism for paternal transmission of environmental information is via the sperm epigenome. These findings should inspire animal industry to increase their consideration of the sire’s environment in the context of optimizing productivity. (This research was funded by CIHR, FRQNT and NSERC.)

The Role of the Epididymis in Linking the Legacy of Paternal Exposures to Alteration of the Sperm Epigenome

In what has become a well-established paradigm, paternal exposure to a range of environmental stressors is known to elicit distinct changes to the sperm small noncoding RNA (sncRNA) profile; modifications that can have significant post-fertilization consequences. Despite this knowledge, there remains limited mechanistic understanding of how paternal exposures modify the sperm sncRNA landscape. To address this question, our laboratory has exploited a tractable exposure model in which male mice were subjected to acute administration of the reproductive toxicant, acrylamide; a challenge that elicited robust changes to their sperm sncRNA profile. Further, we traced the differential accumulation of acrylamide-responsive sncRNAs to coincide with sperm transit of the proximal (caput) segment of the epididymis, wherein acrylamide exposure altered the expression of several transcription factors implicated in the expression of acrylamide-sensitive sncRNAs. We have also identified extracellular vesicles (epididymosomes) secreted from the caput epididymal epithelium in relaying altered sncRNA profiles to maturing spermatozoa, the implications of which manifest in the form of dysregulated gene expression during early embryonic development following fertilization by acrylamide-exposed sperm. Overall, these data provide mechanistic links to account for how environmental insults can alter the sperm epigenome and compromise the transcriptomic profile of early embryos.

CIPHERS: Effects of male marijuana use on sperm health and potential risks to future children

<h2>Abstract</h2> With more prevalent legalization, marijuana has become more widely available and increasingly perceived as safe. Impacts of marijuana use by both parents before conception and during pregnancy is an important topic of study. This video introduces research and findings from the Cannabis-Induced Potential Heritability of Epigenetic Revisions in Sperm (CIPHERS) study at Duke University. Male marijuana use affects sperm health and may pose risks to development of their children. CIPHERS human and rat studies comparing samples from exposed and non-exposed males have shown that marijuana use changes the sperm epigenome in genes associated with growth, development, and behavior. The offspring of male rats inherited these changes and showed behavioral impairments. Further study will determine if human children inherit epigenetic changes and, if so, how it affects health and development. CIPHERS recently found that stopping marijuana use for at least 11 weeks, or one sperm regeneration cycle, reduces the number of sperm showing marijuana-associated epigenetic changes at genes that are important for early childhood development. People need to be aware of the potential health effects caused by male consumption of marijuana and how to reduce risks through marijuana abstinence. This video links to educational resources on the CIPHERS website.

Prepubertal nutritional modulation in the bull and its impact on sperm DNA methylation.

Enhanced pre-pubertal nutrition in Holstein bulls increased reproductive hormone production and sperm production potential with no negative effects on sperm quality. However, recent trends in human epigenetic research have identified pre-pubertal period to be critical for epigenetic reprogramming in males. Our objective was to evaluate the methylation changes in sperm of bulls exposed to different pre-pubertal diets. One-week-old Holstein bull calves (n = 9), randomly allocated to 3 groups, were fed either a high, medium or low diet (20%, 17% or 12.2% crude protein and 67.9%, 66% or 62.9% total digestible nutrients, respectively) from 2 to 32weeks of age, followed by medium nutrition. Semen collected from bulls at two specific time points, i.e. 55-59 and 69-71weeks, was diluted, cryopreserved and used for reduced representation bisulfite sequencing. Differential methylation was detected for dietary treatment, but minimal differences were detected with age. The gene ontology term, "regulation of Rho protein signal transduction", implicated in sperm motility and acrosome reaction, was enriched in both low-vs-high and low-vs-medium datasets. Furthermore, several genes implicated in early embryo and foetal development showed differential methylation for diet. Our results therefore suggest that sperm epigenome keeps the memory of diet during pre-pubertal period in genes important for spermatogenesis, sperm function and early embryo development.

P-068 Oxidative stress and DNA fragmentation of spermatozoa in patients with cancer

Abstract Study question Does cancer increase sperm DNA fragmentation (sDF) level by increasing oxidative stress in human spermatozoa? Summary answer Cancer increases both sDF and oxidative stress, but further studies are necessary to understand whether higher levels of ROS are responsible for sperm DNA damage. What is known already In recent years, it has been emerging that not only oncological therapies but also cancer itself can induce abnormal spermatogenesis. In addition, several Authors reported that occurrence of malignancy provokes also increases of sperm DNA damage, although such finding was not confirmed by others and the possible mechanisms responsible for such damage are presently unknown Study design, size, duration This was a prospective observational study conducted from 2018 to today, conducted in 102 patients affected by cancer and in 66 control subjects. Participants/materials, setting, methods We recruited 102 patients affected by cancer and 66 male partners of infertile couples as control subjects, in the Andrology Clinic of University of Florence. Control subjects were normozoospermic with absence of leukocytospermia, semen viscosity, smoking habit and recent antibiotic therapies. In the recruited men, we evaluated standard semen parameters, sperm DNA Fragmentation with SCD (Sperm Chromatin Dispersion) Test and oxidative stress as percentage of viable spermatozoa with MitoSOX™ Red labeling on total viable spermatozoa. Main results and the role of chance We found poorer standard semen parameters (sperm motility, concentration and number) in cancer patients (both testicular and hematological ones) with respect to control group, whereas no differences were observed between the two types of cancer. Testicular, but not hematological patients, were younger than control subjects. No difference was seen in the other tested characteristics (sperm morphology, abstinence, semen volume and pH, BMI). Regarding sDF, we found higher median values [IQR] in cancer patients (total: 22.25[17.00-25.95], n = 68; hematological: 23.00[20.13-26.38], n = 28; testicular: 21.13[16.13-25.73], n = 40) vs control subjects (12.50[8.25-14.75], n = 53); p &amp;lt; 0.05, test U di Mann-Whitney. In addition, the amount of sperm oxidative stress was dramatically higher in patients with cancer (total:38.92[24.90-58.87], n = 79; hematological: 38.85[24.98-50.77], n = 34; testicular: 38.92[20.59-63.59], n = 45) vs control subjects (11.50[8.38-17.20], n = 62); p &amp;lt; 0.05, test U di Mann-Whitney. We also studied the occurrence of a correlation between levels of sDF and oxidative stress. We found a sharp correlation when both cancer patients and control subjects were analysed (Spearman coefficient = 0.62, p &amp;lt; 0.001, n = 103), but such correlation was completely lost when only cancer patients were considered (Spearman coefficient = 0.10, p &amp;gt; 0.05, n = 50). This finding suggests that mechanisms different from ROS attack to DNA could explain the increase of sDF levels in cancer patients. Limitations, reasons for caution The study did not investigate, because of scarce availability of semen samples from cancer patients, other possible mechanisms (i.e apoptosis, defects in sperm chromatin maturation, failure in DNA system repair) which could cause the observed increase of sperm DNA damage in such patients. Wider implications of the findings Cancer patients show high levels of both sDF and oxidative stress. This finding rises concern, as cancer patients cryopreserve semen for using it with Assisted Reproductive Tecnhologies and both parameters represent a threat for natural and assisted reproduction. In addition, emerging evidence suggest that oxidative stress may alter sperm epigenome. Trial registration number not applicable

Maternal cypermethrin exposure during perinatal period dysregulates gonadal steroidogenesis, gametogenesis and sperm epigenome in F1 rat offspring

Evidences suggest that maternal exposure to endocrine disruptor insecticide cypermethrin (CYP) affects the reproductive functions of offspring. However, its molecular effects are not well researched. This study elucidates the effects of CYP on gonadal steroidogenesis, gametogenesis and sperm epigenome of perinatally exposed F1 rat offspring. CYP (1, 10, 25 mg/kg bw/day) and Diethylestilbestrol (10 µg/kg bw/day; positive control) were gavaged once daily to pregnant dams from gestational day 6 to postnatal day 21 and their effects were assessed in F1 adults. Dysregulated steroidogenesis was observed in F1 testis; expression of Star, Cyp11a1 and Cyp19a1 were upregulated and Hsd3b1, Cyp17a1, Hsd17b3 downregulated. Expression of spermatogenesis cell-type markers Pcna, Plzf, Sohlh2 were upregulated and Ccna1, Sycp1, Ccnb1, Acrv, Amh downregulated. Upon epigenetic investigations of F1 spermatozoa; global hypermethylation, H19 DMR hypomethylation and increased expression of testicular Dnmts were observed. In F1 ovaries, expression of all studied steroidogenesis genes and oogenesis markers such as Amh, Gdf9, Ccnb1 and Pcna were altered. Amh was downregulated and Gdf9 was found to be upregulated. Overall, perinatal CYP exposure hampers molecular control of steroidogenesis and gametogenesis processes along with sperm epigenome in CYP exposed F1 offspring.

Effect of Paternal Diet on Spermatogenesis and Offspring Health: Focus on Epigenetics and Interventions with Food Bioactive Compounds.

Infertility is a growing public health problem. Consumption of antioxidant bioactive food compounds (BFCs) that include micronutrients and non-nutrients has been highlighted as a potential strategy to protect against oxidative and inflammatory damage in the male reproductive system induced by obesity, alcohol, and toxicants and, thus, improve spermatogenesis and the fertility parameters. Paternal consumption of such dietary compounds could not only benefit the fathers but their offspring as well. Studies in the new field of paternal origins of health and disease show that paternal malnutrition can alter sperm epigenome, and this can alter fetal development and program an increased risk of metabolic diseases and breast cancer in adulthood. BFCs, such as ascorbic acid, α-tocopherol, polyunsaturated fatty acids, trace elements, carnitines, N-acetylcysteine, and coenzyme Q10, have been shown to improve male gametogenesis, modulate epigenetics of germ cells, and the epigenetic signature of the offspring, restoring offspring metabolic health induced by stressors during early life. This indicates that, from a father’s perspective, preconception is a valuable window of opportunity to start potential nutritional interventions with these BFCs to maximize sperm epigenetic integrity and promote adequate fetal growth and development, thus preventing chronic disease in adulthood.

Testicular "Inherited Metabolic Memory" of Ancestral High-Fat Diet Is Associated with Sperm sncRNA Content.

Excessive adiposity caused by high-fat diets (HFDs) is associated with testicular metabolic and functional abnormalities up to grand-offspring, but the mechanisms of this epigenetic inheritance are unclear. Here we describe an association of sperm small non-coding RNA (sncRNA) with testicular “inherited metabolic memory” of ancestral HFD, using a transgenerational rodent model. Male founders were fed a standard chow for 200 days (CTRL), HFD for 200 days (HFD), or standard chow for 60 days followed by HFD for 140 days (HFDt). The male offspring and grand-offspring were fed standard chow for 200 days. The sncRNA sequencing from epidydimal spermatozoa revealed signatures associated with testicular metabolic plasticity in HFD-exposed mice and in the unexposed progeny. Sperm tRNA-derived RNA (tsRNA) and repeat-derived small RNA (repRNA) content were specially affected by HFDt and in the offspring of HFD and HFDt mice. The grand-offspring of HFD and HFDt mice showed lower sperm counts than CTRL descendants, whereas the sperm miRNA content was affected. Although the causality between sperm sncRNAs content and transgenerational epigenetic inheritance of HFD-related traits remains elusive, our results suggest that sperm sncRNA content is influenced by ancestral exposure to HFD, contributing to the sperm epigenome up to the grand-offspring.

Species-Specific Paternal Age Effects and Sperm Methylation Levels of Developmentally Important Genes.

A growing number of sperm methylome analyses have identified genomic loci that are susceptible to paternal age effects in a variety of mammalian species, including human, bovine, and mouse. However, there is little overlap between different data sets. Here, we studied whether or not paternal age effects on the sperm epigenome have been conserved in mammalian evolution and compared methylation patterns of orthologous regulatory regions (mainly gene promoters) containing both conserved and non-conserved CpG sites in 94 human, 36 bovine, and 94 mouse sperm samples, using bisulfite pyrosequencing. We discovered three (NFKB2, RASGEF1C, and RPL6) age-related differentially methylated regions (ageDMRs) in humans, four (CHD7, HDAC11, PAK1, and PTK2B) in bovines, and three (Def6, Nrxn2, and Tbx19) in mice. Remarkably, the identified sperm ageDMRs were all species-specific. Most ageDMRs were in genomic regions with medium methylation levels and large methylation variation. Orthologous regions in species not showing this age effect were either hypermethylated (>80%) or hypomethylated (<20%). In humans and mice, ageDMRs lost methylation, whereas bovine ageDMRs gained methylation with age. Our results are in line with the hypothesis that sperm ageDMRs are in regions under epigenomic evolution and may be part of an epigenetic mechanism(s) for lineage-specific environmental adaptations and provide a solid basis for studies on downstream effects in the genes analyzed here.

Sperm histone H3 lysine 4 tri-methylation serves as a metabolic sensor of paternal obesity and is associated with the inheritance of metabolic dysfunction

ObjectiveParental environmental exposures can strongly influence descendant risks for adult disease. How paternal obesity changes the sperm chromatin leading to the acquisition of metabolic disease in offspring remains controversial and ill-defined. The objective of this study was to assess (1) whether obesity induced by a high-fat diet alters sperm histone methylation; (2) whether paternal obesity can induce metabolic disturbances across generations; (3) whether there could be cumulative damage to the sperm epigenome leading to enhanced metabolic dysfunction in descendants; and (4) whether obesity-sensitive regions associate with embryonic epigenetic and transcriptomic profiles. Using a genetic mouse model of epigenetic inheritance, we investigated the role of histone H3 lysine 4 methylation (H3K4me3) in the paternal transmission of metabolic dysfunction. This transgenic mouse overexpresses the histone demethylase enzyme KDM1A in the developing germline and has an altered sperm epigenome at the level of histone H3K4 methylation. We hypothesized that challenging transgenic sires with a high-fat diet would further erode the sperm epigenome and lead to enhanced metabolic disturbances in the next generations. MethodsTo assess whether paternal obesity can have inter- or transgenerational impacts, and if so to identify potential mechanisms of this non-genetic inheritance, we used wild-type C57BL/6NCrl and transgenic males with a pre-existing altered sperm epigenome. To induce obesity, sires were fed either a control or high-fat diet (10% or 60% kcal fat, respectively) for 10–12 weeks, then bred to wild-type C57BL/6NCrl females fed a regular diet. F1 and F2 descendants were characterized for metabolic phenotypes by examining the effects of paternal obesity by sex, on body weight, fat mass distribution, the liver transcriptome, intraperitoneal glucose, and insulin tolerance tests. To determine whether obesity altered the F0 sperm chromatin, native chromatin immunoprecipitation-sequencing targeting H3K4me3 was performed. To gain insight into mechanisms of paternal transmission, we compared our sperm H3K4me3 profiles with embryonic and placental chromatin states, histone modification, and gene expression profiles. ResultsObesity-induced alterations in H3K4me3 occurred in genes implicated in metabolic, inflammatory, and developmental processes. These processes were associated with offspring metabolic dysfunction and corresponded to genes enriched for H3K4me3 in embryos and overlapped embryonic and placenta gene expression profiles. Transgenerational susceptibility to metabolic disease was only observed when obese F0 had a pre-existing modified sperm epigenome. This coincided with increased H3K4me3 alterations in sperm and more severe phenotypes affecting their offspring. ConclusionsOur data suggest sperm H3K4me3 might serve as a metabolic sensor that connects paternal diet with offspring phenotypes via the placenta. This non-DNA-based knowledge of inheritance has the potential to improve our understanding of how environment shapes heritability and may lead to novel routes for the prevention of disease. This study highlights the need to further study the connection between the sperm epigenome, placental development, and children's health. Summary sentencePaternal obesity impacts sperm H3K4me3 and is associated with placenta, embryonic and metabolic outcomes in descendants.