Previous studies from our lab modelling chronic stress exposure through paternal corticosterone supplementation preconception revealed altered anxiety and depression-relevant behaviours in male progeny. Given the strong presence of sociability deficits in various affective disorders, we sought to characterise social behaviour across generations in our model. Additionally, we had reported significant changes to sperm sncRNA content associated with corticosterone supplementation but DNA methylation, a key epigenetic modification, had yet to be investigated.
Two generations of adult male progeny derived from C57BL/6J male mice treated with corticosterone for 4 weeks prior to paired-matings were assessed using the Mate-Choice Test. This involved a modified 3-chamber interaction test, where female mice on oestrous explored the apparatus while the males were contained, indicating their relative attractiveness. Protein concentration and gene expression of the male pheromone Major Urinary Protein (MUP) were quantified in urine and liver, respectively. Sperm from corticosterone-treated mice were harvested from the caudal epididymis and DNA was extracted, then processed for Oxford Nanopore long-read sequencing, followed by in-house bioinformatic analyses to detect differential methylation.
Paternal corticosterone exposure was associated with increased female attraction towards male offspring (PatCORT), with no differences observed for grand offspring (GPatCORT). These observations were not attributable solely to an overall change in urinary MUP protein levels. However, specific MUP subtypes (MUP20 and Major MUP bands) were found to be decreased in PatCORT urine. No differences in these MUP subtypes were found from GPatCORT urine. Interestingly, we found that corticosterone-treatment resulted in altered sperm DNA methylation in regions proximal to Mup genes.
Paternal stress preconception may influence social behaviour intergenerationally, as we found altered male attractiveness across one generation of progeny. These changes were unexpectedly accompanied by lower urinary MUP levels in the male offspring. Further investigations into the male PatCORT response to female urine could clarify these results.