Society for Neuroscience

PTEN hamartoma tumour syndrome (PHTS) is a rare disease (incidence 1:200,000) arising from germline mutations in PTEN. Approximately 25% of people with PHTS meet diagnostic criteria of autism spectrum disorder (ASD) [1] and ~2% of individuals with ASD may harbour a germline PTEN mutation [2]. Such PTEN mutations lead to an upregulation of PI3K-Akt-mTOR signaling that has been associated with macrocephaly and structural and functional changes in hippocampal and cortical neurons in both human and murine CNS. Animal models with PTEN loss show neuronal hyperexcitability and seizure development. Our PTEN knockdown (PTEN KD) hippocampal neuron cell model showed upregulation of PI3K-Akt-mTOR signaling. Micro-electrode array (MEA) in vitro assays offer valuable insights into cellular behavior, particularly in neurons, by measuring electrical activity noninvasively across a cell population over time using electrodes. We showed that AAV shRNA mediated PTEN KD neurons exhibit a consistent increase (e.g., burst duration and network burst duration) and decrease (network burst frequency) over time for a subset of neuronal network parameters linked to neuronal excitability. Rapamycin, an inhibitor of mTOR restored these functional parameters in PTEN KD cells in the direction of non-target shRNA control cells. A structured statistical framework was applied to evaluate the activity of Rapamycin, accounting for experimental variability and potential neurotoxicity over time. Applying the MEA assay to complement other measures of PTEN loss in neurons provides data that may further discriminate between inhibitors of PI3K signaling as drug repurposing candidates