Developmental pyrethroid exposure disrupts folate metabolism in mouse brain

Environmental and genetic risk factors, and their interactions, contribute significantly to the etiology of neurodevelopmental disorders (NDDs). Recent epidemiology studies have implicated pyrethroid pesticides as an environmental risk factor for autism and developmental delay. Our previous research showed that low-dose developmental exposure to the pyrethroid pesticide deltamethrin in mice caused male-biased changes in the brain and in NDD-relevant behaviors that persisted into adulthood. Here, we used a metabolomics approach to determine the broadest possible set of metabolic changes in the adult male mouse brain caused by low-dose developmental pyrethroid exposure. Using a litter-based design, we exposed mouse dams during pregnancy and lactation to deltamethrin (3 mg/kg or vehicle every 3 days) at a concentration well below the EPA-determined benchmark dose used for regulatory guidance. We raised male offspring to adulthood and collected whole brain samples for untargeted high-resolution metabolomics analysis. Developmentally exposed mice had disruptions in 116 metabolites which clustered into pathways for folate biosynthesis, retinol metabolism, and tryptophan metabolism. Perturbagen analysis on split-sample transcriptomics data from the same mice identified a folate inhibitor as the drug causing the most similar effect to DPE, thus confirming that developmental pyrethroid exposure disrupted folate metabolism. These results suggest that DPE directly disrupts folate metabolism in the brain, which may inform both prevention and therapeutic strategies.