The ketone body β-hydroxybutyrate ameliorates neurodevelopmental deficits in the GABAergic system of mutants.

A finely tuned balance between excitation and inhibition (E/I) is essential for proper brain function. Disruptions in the GABAergic system, which alter this equilibrium, are a common feature in various types of neurological disorders, including autism spectrum disorders (ASDs). Mutations in , the main negative regulator of the phosphatidylinositol 3-phosphate kinase/Akt pathway, are strongly associated with ASD. However, it is unclear whether deficiencies can differentially affect inhibitory and excitatory signaling. Using the neuromuscular system, where both excitatory (cholinergic) and inhibitory (GABAergic) inputs regulate muscle activity, we found that / mutations impact GABAergic (but not cholinergic) neurodevelopment and function. This selective impact results in a deficiency in inhibitory signaling. The defects observed in the GABAergic system in mutants are due to reduced activity of DAF-16/FOXO during development. Ketogenic diets (KGDs) have proven effective for disorders associated with E/I imbalances. However, the mechanisms underlying their action remain largely elusive. We found that a diet enriched with the ketone body β-hydroxybutyrate during early development induces DAF-16/FOXO activity, therefore improving GABAergic neurodevelopment and function in mutants. Our study provides valuable insights into the link between mutations and neurodevelopmental defects and delves into the mechanisms underlying the potential therapeutic effects of KGDs.