Non-synaptic Cell-Autonomous Mechanisms Underlie Neuronal Hyperactivity in a Genetic Model of PIK3CA-Driven...

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Mutations in PI3K-AKT-MTOR pathway genes are linked to neurodevelopmental disorders, including drug-resistant epilepsy.
• PIK3CA mutations are a known cause of these disorders, necessitating targeted therapies.

Purpose of the Study:

• To elucidate the physiological mechanisms of neuronal hyperactivity in a PIK3CA-mutant epilepsy model.
• To identify specific pathway targets for acute therapeutic intervention.

Main Methods:

• In vivo electrophysiology to detect epileptiform events in Pik3ca mutant hippocampi.
• Ex vivo analyses of hippocampal pyramidal neurons to assess cell-intrinsic properties.
• Pharmacological inhibition of PI3K, AKT, and MTOR pathways.

Main Results:

• Pik3ca mutation induced epileptiform activity in the hippocampus.
• Hyperactivation of hippocampal neurons was linked to cell-intrinsic properties, not synaptic changes.
• Acute PI3K or AKT inhibition, but not MTOR inhibition, reduced neuronal hyperactivity.

Conclusions:

• PI3K-AKT pathway dysregulation underlies epilepsy in PIK3CA mutation carriers.
• Acute PI3K or AKT inhibition represents a potential therapeutic strategy for intractable epilepsy.
• These findings differentiate mechanisms from other AKT-MTOR related epilepsy models.