Glyphosate Induced Transgenerational DNA Methylation and Histone Retention Sperm Epigenetic Biomarkers for Disease
The herbicide glyphosate has been shown to promote the epigenetic transgenerational inheritance of pathology and disease in subsequent great-grand offspring (F3 generation). This generational toxicology suggests the impacts of environmental exposures need to assess subsequent generations. The current study was designed to identify epigenetic biomarkers for glyphosate induced transgenerational disease. Following a transient glyphosate exposure of a gestating female rat (F0 generation), the subsequent transgenerational F3 generation, with no direct exposure, were aged to 1 year and animals with specific pathologies identified. The pathologies investigated included prostate disease, kidney disease, obesity, and presence of multiple disease. The sperm were collected from the males and used to identify specific differential DNA methylation regions (DMRs) associated with the pathologies. In addition, the differential histone retention sites (DHRs) were examined for the various pathologies as well. Unique signatures of DMRs and DHRs for each pathology were identified for the specific diseases. Interestingly, at a lower statistical threshold overlapping sets of DMRs and DHRs were identified that were common for all the pathologies. The DMR and DHR gene associations were identified and correlated with known pathology associated genes. While the disease biomarker DMR and DHR did not meet typical statistical significance levels, these results may help design future studies with reduced variability. Observations indicate transgenerational epigenetic biomarkers of disease pathology can potentially be identified in the sperm that can assess disease susceptibility. These biomarkers may also suggest epigenetic diagnostics could be used to facilitate preventative medicine. Overall design: Analysis of the transgenerational actions of glyphosate used outbred Sprague Dawley female rats (F0 generation) transiently exposed (25 mg/kg body weight glyphosate daily) during days 8 to 14 of gestation. The F1 generation animals (direct fetal exposure) were bred to generate the F2 generation (direct germline exposure), which were bred to generate the F3 generation (transgenerational so no direct exposure). A control lineage used F0 generation gestating females administered vehicle control dimethyl sulfoxide (DMSO) or phosphate buffered saline (PBS). The control and glyphosate lineages were aged to 1 year and euthanized for pathology and sperm epigenetic analysis. No sibling or cousin breedings (crosses) were used to avoid any inbreeding artifacts in either the control or glyphosate lineages. Generally 6–8 founder gestating females from different litters were bred and 25–50 individuals of each sex obtained for each generation.