Project description:The goals of this study are to compare genome-wide DNA methylation levels in young and aged oocytes,and to investigate the transgenerational inheritance of methylome profiles in oocytes during natural aging. We apply a novel protocol of rapamycin to overcome the DNA methylation drift associated with oocyte aging. 8-week-old female mice were injected intraperitoneally with rapamycin or vehicle for 40 weeks. At the end of the experiment, females (48 weeks, F0) were paired with young adult (~4 mo old) males to produce F1 offspring (OF1 and ORaF1). An F2 generation (OF2 and ORaF2) resulted from mating F1 female at 44~48 weeks of age with young adult males. To generate YF1 and YF2 as normal control (offspring of young mother), we mated females (~8 weeks) with young adult males. Then we collect oocytes (F0,F1 and F2 generations),sperm ( F1 and F2 generations) and hippocampus (F1 female offspring) from different groups to investigate the transgenerational inheritance of DNA methylome profiles associated with oocyte aging by the single cell whole-genome methylation sequencing (sc-WGBS). We found that oocytes from aged mother exhibited increased DNA methylation levels in CpG sites. Maternal aging related methylome changes can be inherited transgenerationally though oocyte to the germ line of F1 and F2 offspring. The application of rapamycin during the course of oocyte aging could reverse these DNA methylation alterations, and it can ameliorate several neurobehavioral aging trails that were in observed in aged oocyte offspring. WGBS-seq on DNA from hippocampal tissue revealed a number of differentially methylated (P<0.05) genes in OF1 and ORaF1 compared with YF1, and some of the enriched pathways were associated with aging process, such as PI3K-Akt signaling pathway (akin to transcriptional alterations above), MAPK signaling and Ras signaling pathway .
Project description:Environmental compounds can promote epigenetic transgenerational inheritance of adult-onset disease in subsequent generations following ancestral exposure during fetal gonadal sex determination. The current study examined the ability of dioxin (2,3,7,8-tetrachlorodibenzo[p]dioxin, TCDD) to promote epigenetic transgenerational inheritance of disease and DNA methylation epimutations in sperm. Gestating F0 generation females were exposed to dioxin during fetal day 8 to 14 and adult-onset disease was evaluated in F1 and F3 generation rats. The incidences of total disease and multiple disease increased in F1 and F3 generations. Prostate disease, ovarian primordial follicle loss and polycystic ovary disease were increased in F1 generation dioxin lineage. Kidney disease in males, pubertal abnormalities in females, ovarian primordial follicle loss and polycystic ovary disease were increased in F3 generation dioxin lineage animals. Analysis of the F3 generation sperm epigenome identified 50 differentially DNA methylated regions (DMR) in gene promoters. These DMR provide potential epigenetic biomarkers for transgenerational disease and ancestral environmental exposures. Observations demonstrate dioxin exposure of a gestating female promotes epigenetic transgenerational inheritance of adult onset disease and sperm epimutations.
Project description:Background: DNA methylation (DNAme) erasure and reacquisition occurs during prenatal male germ cell development; some further remodelling takes place after birth during spermatogenesis. Environmental insults during germline epigenetic reprogramming may affect DNAme, presenting a potential mechanism for transmission of environmental exposures across multiple generations. Objectives: We investigated how germ cell DNAme is impacted by lifetime exposures to diets containing either low or high, clinically relevant, levels of the methyl donor folic acid and whether resulting DNAme alterations were inherited in germ cells of male offspring of subsequent generations. Materials and Methods: Female mice were placed on a 7-fold folic acid deficient (7FD) and 10- or 20-fold supplemented (10FS and 20FS) diets before and during pregnancy. Resulting F1 litters were weaned on the respective diets. F2 and F3 males received control diets. Genome-wide DNAme was assessed in F1 spermatogonia, and in F1, F2 and F3 sperm. Results: In F1 germ cells, a greater number of differentially methylated cytosines (DMCs) was observed in spermatogonia as compared with F1 sperm for all folic acid diets. DMCs were lower in number in F2 versus F1 sperm, while an unexpected increase was found in F3 sperm. DMCs were predominantly hypomethylated, with genes in neurodevelopmental pathways commonly affected in F1, F2 and F3 male germ cells. While no DMCs were found to be inherited inter- or transgenerationally, we observed over-representation of repetitive elements, particularly young LINEs. Discussion and Conclusion: These results suggest that the prenatal window is the time most susceptible to folate-induced alterations in sperm DNAme in male germ cells. Altered methylation of specific sites in F1 sperm was not present in later generations. However, the finding of hypomethylated young LINE1 elements in sperm from F1 to F3 males provides insight into potential mechanisms of epigenetic inheritance of the effects of folate deficiency and supplementation.
Project description:Hearts from young (2-4 month) and moderately aged (16-18 month) C57/Bl6 male mice were subjected to i) 20 min global ischaemia, 60 min reperfusion or ii) 80 min aerobic perfusion/normoxia.
Project description:Environmental factors during fetal development can induce a permanent epigenetic change in the germ line (sperm) that then transmits epigenetic transgenerational inheritance of adult-onset disease in the absence of any subsequent exposure. The epigenetic transgenerational actions of various environmental compounds and relevant mixtures were investigated with the use of a pesticide mixture (permethrin and insect repellant DEET), a plastic mixture (bisphenol A and phthalates), dioxin (TCDD) and a hydrocarbon mixture (jet fuel, JP8). After transient exposure of F0 gestating female rats during the period of embryonic gonadal sex determination, the subsequent F1-F3 generations were obtained in the absence of any environmental exposure. The effects on the F1, F2 and F3 generations pubertal onset and gonadal function were assessed. The plastics, dioxin and jet fuel were found to promote early-onset female puberty transgenerationally (F3 generation). Spermatogenic cell apoptosis was affected transgenerationally. Ovarian primordial follicle pool size was significantly decreased with all treatments transgenerationally. Differential DNA methylation of the F3 generation sperm promoter epigenome was examined. Differential DNA methylation regions (DMR) were identified in the sperm of all exposure lineage males and found to be consistent within a specific exposure lineage, but different between the exposures. Several genomic features of the DMR, such as low density CpG content, were identified. Exposure-specific epigenetic biomarkers were identified that may allow for the assessment of ancestral environmental exposures associated with adult onset disease. Environmental factors during fetal development can induce a permanent epigenetic change in the germ line (sperm) that then transmits epigenetic transgenerational inheritance of adult-onset disease in the absence of any subsequent exposure. The epigenetic transgenerational actions of various environmental compounds and relevant mixtures were investigated with the use of a pesticide mixture (permethrin and insect repellant DEET), a plastic mixture (bisphenol A and phthalates), dioxin (TCDD) and a hydrocarbon mixture (jet fuel, JP8). After transient exposure of F0 gestating female rats during the period of embryonic gonadal sex determination, the subsequent F1-F3 generations were obtained in the absence of any environmental exposure. The effects on the F1, F2 and F3 generations pubertal onset and gonadal function were assessed. The plastics, dioxin and jet fuel were found to promote early-onset female puberty transgenerationally (F3 generation). Spermatogenic cell apoptosis was affected transgenerationally. Ovarian primordial follicle pool size was significantly decreased with all treatments transgenerationally. Differential DNA methylation of the F3 generation sperm promoter epigenome was examined. Differential DNA methylation regions (DMR) were identified in the sperm of all exposure lineage males and found to be consistent within a specific exposure lineage, but different between the exposures. Several genomic features of the DMR, such as low density CpG content, were identified. Exposure-specific epigenetic biomarkers were identified that may allow for the assessment of ancestral environmental exposures associated with adult onset disease.
Project description:The agricultural fungicide vinclozolin exposure of a gestating female rat has previously been shown to promote transgenerational disease and epimutations in F3 generation (great-grand-offspring) animals. The current study was designed to investigate the actions of direct fetal exposure on the F1 generation rat sperm DMRs compared to the F3 transgenerational sperm DMRs. The F1 generation DMRs were found to be fewer in number and for the most part distinct from the F3 generation epimutations. Therefore, the direct exposure induced F1 generation DMRs appear to promote alterations in germ cell development that lead to the programming of the F3 generation epimutations, but are distinct between the generations.
Project description:Environmental compounds can promote epigenetic transgenerational inheritance of adult-onset disease in subsequent generations following ancestral exposure during fetal gonadal sex determination. The current study examined the ability of dioxin (2,3,7,8-tetrachlorodibenzo[p]dioxin, TCDD) to promote epigenetic transgenerational inheritance of disease and DNA methylation epimutations in sperm. Gestating F0 generation females were exposed to dioxin during fetal day 8 to 14 and adult-onset disease was evaluated in F1 and F3 generation rats. The incidences of total disease and multiple disease increased in F1 and F3 generations. Prostate disease, ovarian primordial follicle loss and polycystic ovary disease were increased in F1 generation dioxin lineage. Kidney disease in males, pubertal abnormalities in females, ovarian primordial follicle loss and polycystic ovary disease were increased in F3 generation dioxin lineage animals. Analysis of the F3 generation sperm epigenome identified 50 differentially DNA methylated regions (DMR) in gene promoters. These DMR provide potential epigenetic biomarkers for transgenerational disease and ancestral environmental exposures. Observations demonstrate dioxin exposure of a gestating female promotes epigenetic transgenerational inheritance of adult onset disease and sperm epimutations. Methylated sperm DNA was isolated from rats ancestrally exposed to dioxin (Hip). Three independent samples from the treatment group were obtained. Differential DNA methylation between treatment groups was determined using Nimblegen microarrays. Treated samples were paired with control samples and hybridized together on arrays (Hip1/Cip1, Hip2/Cip2, and Hip3/Cip3), resulting in three arrays for the treatment.
Project description:Gestating F0 generational female rats were transiently exposed to DDT during fetal gonadal sex determination and the incidence of adult onset pathologies was assessed in the subsequent F1, F2, and F3 generations. In addition, sperm differential DNA methylation regions (DMRs) that were associated with specific pathologies in the F3 generation males were investigated. No pathology was observed in the F1 generation DDT lineage males or females compared with F1 generation controls (vehicle exposure). There was an increase of testis disease and early onset puberty in the F2 generation DDT lineage males. The F3 generation DDT males had significant increases in testis disease, prostate disease, and late onset puberty. The F3 generation DDT females had significant increases in ovarian and kidney disease. Both the F3 generation males and females had significant increases in the frequency of obesity and multiple disease. The F3 generation sperm was collected to examine DMRs for the ancestrally exposed DDT male population. Unique sets of DMRs were associated with late onset puberty, kidney disease, and multiple disease pathologies.
Project description:Adult female Wistar rats (about 220g) obtained from a breeding colony were mated and fed either a protein sufficient (PS) or protein restricted (PR) diet (n = 6 per dietary group) during F0 pregnancy which provided an increase in energy of approximately 25% compared to the diet fed to the breeding colony (2018S). During lactation dams were fed AIN93G and litters were standardisied to 8 offspring within 24 hours of birth with a bias towards females. Offpsring were weaned onto AIN93M at postnatal day 28 and F1 and F2 females were mated on postnatal day 70 (n = 6 per F0 dietary group). F1 and F2 dams were fed the PS diet during pregnancy and AIN93G during lactation. Offspring were weaned onto AIN93M. On postnatal day 70 unmated female offspring were fasted for 12 hours then sacrificed for hepatic transcritpome analysis by microarray. Expression of 1,684 genes differed by at least 2 fold between adult female F1 offspring of F0 dams from both dietary groups. 1680 genes were altered in F2 offspring and 2,065 genes altered in F3 offspring. Expression of 113 genes was altered in all three generations. Of these, 47% showed directionally opposite differences between generations. Gene ontology analysis revealed clear differences in the pathways altered in each generation. F1 and F2 offspring of F0 dams fed a PR diet showed impaired fasting glucose homeostasis. Hepatic phosphoenolpyruvate carboxykinase (PEPCK) expression was elevated in F1 and F2 offspring from F0 PR dams, but decreased in F3, compared to PS offspring
Project description:We report the effect of histone trimethylation on transgenerational inheritance. We exposed outbred pregnant CD1 mice to herbicide atrazine and progeny of these mice were crossed for a three generations. First (F1) and third (F3) generation of males were analyzed by using genome-wide sequencing analysis. We analyzed the RNA expression level in liver, brain (hypothalamus) and testis in F3 generation males. The testis samples of F1 and F3 generations’ males were analyzed by ChIP-seq using antibody against H3K4me3. We find that subset of H3K4me3 marks altered in F1 was also detected in F3 males progeny. This subset is enriched in genes of stem cell differentiation. We found that embryonic exposure to atrazine globally affects the RNA transcription in testis: we found the tissue-specific transcription deregulation, increased number transcripts with altered transcription start site, alternatively spliced and polyadenylated mRNA transcripts in a F3 generation males. This study provides a new knowledge of mechanisms of transgenerational inheritance exposed to toxic compounds.