Prenatal 1‐Nitropyrene Exposure Causes Autism‐Like Behavior Partially by Altering DNA Hydroxymethylation in Developing Brain

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, characterized by social communication disability and stereotypic behavior. This study aims to investigate the impact of prenatal exposure to 1‐nitropyrene (1‐NP), a key component of motor vehicle exhaust, on autism‐like behaviors in a mouse model. Three‐chamber test finds that prenatal 1‐NP exposure causes autism‐like behaviors during the weaning period. Patch clamp shows that inhibitory synaptic transmission is reduced in medial prefrontal cortex of 1‐NP‐exposed weaning pups. Immunofluorescence finds that prenatal 1‐NP exposure reduces the number of prefrontal glutamate decarboxylase 67 (GAD67) positive interneurons in fetuses and weaning pups. Moreover, prenatal 1‐NP exposure retards tangential migration of GAD67‐positive interneurons and downregulates interneuron migration‐related genes, such as Nrg1, Erbb4, and Sema3F, in fetal forebrain. Mechanistically, prenatal 1‐NP exposure reduces hydroxymethylation of interneuron migration‐related genes through inhibiting ten‐eleven translocation (TET) activity in fetal forebrain. Supplement with alpha‐ketoglutarate (α‐KG), a cofactor of TET enzyme, reverses 1‐NP‐induced hypohydroxymethylation at specific sites of interneuron migration‐related genes. Moreover, α‐KG supplement alleviates 1‐NP‐induced migration retardation of interneurons in fetal forebrain. Finally, maternal α‐KG supplement improves 1‐NP‐induced autism‐like behaviors in weaning offspring. In conclusion, prenatal 1‐NP exposure causes autism‐like behavior partially by altering DNA hydroxymethylation of interneuron migration‐related genes in developing brain.