Maternal immune activation perturbs the brain epitranscriptome

Maternal immune activation (MIA) results in abnormal fetal neurodevelopment and an increased risk of neurodevelopmental disorders. Altered RNA translation has been implicated in the pathophysiology of MIA-associated neurodevelopmental deficits, but more precise mechanisms underlying disruption in RNA metabolism are lacking. Here, we characterize key components of the RNA epitranscriptomic machinery, which refers to the set of reversible chemical modifications on RNA molecules that influence RNA function, including translation, stability, splicing, and localization. Using spatial transcriptomics, we define cell type- and brain region-specific distribution of epitranscriptome regulators in the developing mouse brain. We also use direct RNA sequencing to define how MIA changes the brain epitranscriptome landscape. We identify the demethylase FTO as being notably perturbed in the context of MIA. Using pharmacological and genetic approaches, we target FTO to ameliorate behavioral phenotypes in MIA offspring. In total, this work expands upon mechanisms of translational misregulation in MIA and identifies new targets for therapeutic manipulation.