Paternal early-life stress and diet influence sperm DNA methylation, female offspring behavior and amygdala transcription

Abstract Obesity is a global epidemic influenced by stress-related experiences during development, which can program behavioral traits, with the amygdala playing a central role in stress regulation. These programmed effects may be inherited through epigenetic mechanisms. Here, we examined the impact of paternal early-life stress (ELS), alone or combined with a high-fat diet (HFD), on offspring behavior and gene regulation. Male Wistar rats underwent maternal separation to induce ELS, followed by elevated plus maze (EPM) testing and exposure to either HFD or standard chow. These males were bred with naïve females, and F 1 offspring were raised under standard conditions. Amygdala tissue and sperm were collected; RNA from paternal and offspring amygdalae was deep-sequenced, and sperm DNA was analyzed using Reduced Representation Bisulfite Deep Sequencing (RRBS). Paternal exposure to ELS and HFD independently and jointly altered physiology and behavior in F 1 female offspring. Offspring of ELS fathers showed increased exploratory behavior and mobility in the EPM; paternal HFD increased time spent in open arms. In the paternal amygdala, ELS and HFD induced distinct gene expression changes. Sperm methylation analysis revealed many differentially methylated genes, some overlapping with transcriptional changes in the F 1 female amygdala, consistent with a potential role for epigenetic inheritance. Overlapping expression patterns in F 0 and F 1 included genes involved in dopamine signaling and epigenetic regulation. Notably, the imprinted gene GRB10 showed increased promoter methylation in sperm and reduced expression in both paternal and offspring amygdala, validated by immunostaining. These findings suggest that paternal ELS and HFD shape offspring phenotype through heritable epigenetic modifications.