AAV-mediated gene therapy for focal epilepsy by expressing neuropeptide Y and Y2 receptor in rodent and non-human primate hippocampus

Epilepsy affects approximately 50 million people worldwide, and over 30% of patients are considered treatment resistant to currently available anti-seizure drugs. Neuropeptide Y (NPY) has been shown to inhibit excitatory synaptic transmission in hippocampal slices from human epilepsy patients via Y2 receptors (Y2Rs), and overexpression of NPY and/or Y2R in the hippocampus reduces seizures in rodent models of epilepsy. In this study, we demonstrate that AAV-mediated delivery of NPY and Y2R using a novel vector (SPK100.NPY-Y2R) inhibits seizures in rodents. SPK100.NPY-Y2R reduced spontaneous neuronal activity in primary rat cortical cultures and attenuated evoked neuronal activity in ex vivo slices of mouse hippocampus. Furthermore, intrahippocampal administration of SPK100.NPY-Y2R reduced the progression and duration of seizures in a rat model of rapid kindling. Parallel experiments confirmed that hippocampal overexpression of NPY and Y2R is also sufficient to reduce spontaneous seizures in a genetic mouse model of epilepsy (synapsin triple knockout). We also demonstrated successful magnetic resonance-guided convection enhanced delivery of SPK100.NPY-Y2R to the hippocampus of Papio hamadryas (baboon). This approach achieved favorable vector biodistribution and transduction in the hippocampus, with no observed adverse events. These findings support the development of an intrahippocampal AAV.NPY-Y2R therapy for treating seizures in patients with temporal lobe epilepsy.