Epigenome-Wide Association Study for Transgenerational Disease Epimutation Sperm Biomarkers following Ancestral Exposure to Jet Fuel Hydrocarbons

Jet fuel hydrocarbons is the generic name for aviation fuels used in gas-turbine engine powered aircrafts. Due to the widespread use of jet fuel hydrocarbons, this compound has been recognized as the single largest chemical exposure for military personnel. Previous animal studies have demonstrated the ability of jet fuel (JP-8) exposure to promote the epigenetic transgenerational inheritance of disease susceptibility in subsequent generations. The diseases observed include late puberty, kidney, obesity and multiple disease pathologies. The current study was designed to identify potential sperm DNA methylation biomarkers for specific transgenerational diseases. Observations identify few disease specific differential DNA methylation regions (DMRs) called epimutations in the transgenerational F3 generation great-grand-offspring rats ancestrally exposed to jet fuel. The potential epigenetic DMRs were identified for late puberty, kidney, obesity, and multiple diseases, and found to be predominantly disease specific. These disease specific DMRs have associated genes previously shown to be linked with each of these specific diseases. Therefore, the germline (i.e. sperm) has environmentally induced ancestrally derived epimutations that have the potential to transgenerationally transmit disease susceptibilities to subsequent generations. Epigenetic biomarkers for specific diseases could be developed as medical diagnostics to facilitate clinical management of disease and allow preventative medicine therapeutics. From embryonic day E8 to E14 the F0 generation gestating females were administered daily intraperitoneal injections of JP-8 hydrocarbon (jet fuel obtained from Lt Dean Wagner, Dayton, OH), 500 mg/kg BW/day, or dimethyl sulfoxide (DMSO) (vehicle) with an equal volume of sesame oil (Sigma) to prevent irritation at the injection site. The no observable adverse effect level (NOAEL) for JP-8 is 500-1000 mg/kg BW/day. The offspring F1, F2 and F3 generations were all aged to 90 days of age and bred within the generation and within the jet fuel lineage. The F3 generation is the first without a direct exposure to jet fuel and is thus called the transgenerational generation. All the animals were aged to 1 year and euthanized for pathology and sperm collected for epigenetic analyses. No sibling or cousin breeding was used to prevent any inbreeding artifacts in the control or jet fuel lineages. An MeDIP-seq approach was used to identify DMRs associated with specific transgenerational diseases.