Maternal high fat and high sugar diet impacts on key DNA methylation enzymes in offspring brain in a sex-specific manner.

Maternal obesity associates with an increased risk of offspring neurodevelopmental disorders. Although the underlying mechanism(s) remain unclear, evidence suggests a role for altered DNA methylation. We utilized a murine model of diet-induced obesity to investigate the impact of maternal obesity on the offspring brain transcriptome and DNA methylation. C57Bl/6 dams were fed high-fat high-sugar (HFD, n = 7) or control (CON, n = 7) diets. Maternal obesity/hyperglycemia associated with offspring growth restriction, with brain-sparing specifically in females. Postnatal hypoglycemia was seen in HFD males, but not females. The 3' RNA-sequencing revealed perturbations in metabolic and cell differentiation pathways in neonatal male and female offspring frontal cortex and cerebellum. Compared with controls, HFD males, but not females, had lower cortical and cerebellar DNMT gene and protein expression, and reduced cerebellar TET enzyme mRNA. Whilst female offspring had lower cerebellar 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) than males, there were no effects of HFD on 5mC/5hmC in cortex or cerebellum in either sex. Our data suggest that maternal obesity has sex-specific effects on fetal neurodevelopment, including enzymes involved in DNA methylation/demethylation. These mechanisms may play a role in the increased risk of neurodevelopmental disorders following obese/diabetic pregnancies, including increased male susceptibility to these disorders.