Project description:Several epigenome-wide association studies (EWAS) have been shown to identify epigenetic alterations (i.e., epimutations) associated with diseases. The sperm epimutations potentially involved in the transgenerational inheritance of specific pathologies have been identified. Transgenerational sperm epimutations associated with kidney, prostate, puberty, testis, obesity, and multiple pathologies have been identified for a variety of environmental toxicants including dioxin, plastics, pesticides, glyphosate, methoxychlor, atrazine, and jet fuel. The transgenerational sperm epimutations for exposure and disease-specific epimutations have been identified in these EWAS studies. The current study used the information from these previous toxicant-induced epigenetic transgenerational inheritance EWAS rat studies and adds a comparable control group, rats that have not been exposed to any particular toxicant. Two additional control groups were collected and are presented here.
Project description:Some epigenetic modifications are inherited from one generation to the next, providing a potential mechanism for the inheritance of environmentally acquired traits. Transgenerational inheritance of RNA interference phenotypes in C. elegans provides an excellent model to study this phenomenon, and whilst studies have implicated both chromatin modifications and small RNA pathways in heritable silencing their relative contributions remain unclear. Here we demonstrate that the histone methyltransferases SET-25 and SET-32 are required for the establishment of a transgenerational silencing signal, but not for long-term maintenance of this signal between subsequent generations suggesting that transgenerational epigenetic inheritance is a multi-step process, with distinct genetic requirements for establishment and maintenance of heritable silencing. Furthermore, small RNA sequencing reveals that the abundance of secondary siRNA (thought to be the effector molecules of heritable silencing) does not correlate with silencing phenotypes. Together, our results suggest that the current mechanistic models of epigenetic inheritance are incomplete.
Project description:Atrazine is a common agricultural herbicide previously shown to promote epigenetic transgenerational inheritance of disease to subsequent generations. The current study was designed as an epigenome-wide association study (EWAS) to identify transgenerational sperm disease associated differential histone retention regions (DHRs). Gestating female F0 generation rats were transiently exposed to atrazine during the period of embryonic gonadal sex determination, and then subsequent F1, F2, and F3 generations obtained in the absence of any continued exposure. The transgenerational F3 generation males were assessed for disease and sperm collected for epigenetic analysis. Pathology was observed in late pubertal onset and for testis disease, prostate disease, kidney disease, lean pathology, and multiple disease. For these pathologies, sufficient numbers of individual males with only a single specific disease were identified. The sperm DNA and chromatin were isolated from adult one-year animals with the specific diseases and analyzed for DHRs with histone chromatin immunoprecipitation (ChIP) sequencing. Transgenerational F3 generation males with or without disease were compared to identify the disease specific epimutation biomarkers. No common DHRs were found among all the pathologies. Epimutation gene associations were identified and found to correlate to previously known disease linked genes.
Project description:A number of environmental factors (e.g. toxicants) have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation. Transgenerational inheritance requires the germline transmission of altered epigenetic information between generations in the absence of direct environmental exposures. The primary periods for epigenetic programming of the germline is associated with primordial germ cell development and during fetal gonadal sex determination. The current study examined the actions of an agricultural fungicide vinclozolin on gestating female (F0 generation) progeny in regards to the primordial germ cell (PGC) epigenetic reprogramming of the F3 generation (i.e. great-grandchildren). The F3 generation primordial germ cell transcriptome and epigenome (DNA methylation) was altered transgenerationally. Interestingly, the differential DNA methylation regions (DMR) and altered transcriptomes were distinct between the onset of gonadal sex determination at embryonic day 13 (E13) and after cord formation in the testis at embryonic day 16 (E16). A larger number of DMR and transcriptional alterations were observed in the E13 PGC than E16 germ cells. Observations demonstrate an altered transgenerational epigenetic reprogramming and function of the primordial germ cells and subsequent male germline is a component of vinclozolin induced epigenetic transgenerational inheritance of disease. Insights into the molecular control of germline transmitted epigenetic inheritance are provided. The combined observations demonstrate ancestral exposure of a gestating female during fetal gonadal sex determination can promote transgenerational alterations in the primordial germ cell and subsequent male germline epigenetic and transcriptional programming. This altered germline programming leads to the epigenetic transgenerational inheritance of disease and phenotypic variation. Observations support the role of the primordial germ cell programming in the molecular mechanism involved and provides insights into the molecular mechanisms that control the epigenetic transgenerational inheritance phenomena. Results suggest a cascade of epigenetic and transcriptional events during germ cell development is needed to obtain the mature germline epigenome that is then transmitted transgenerationally. RNA samples from PGC of 2 F3-control lineage groups were compared to PGC of 2 F3-vinclozolin lineage groups for two embryonic age E13 and E16
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.
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.