BBB disruption using focused ultrasound for gene delivery in Angelman Syndrome

Angelman Syndrome (AS) is a neurodevelopmental disorder caused by loss of maternal UBE3A expression, resulting in developmental delays, motor and speech impairment, and epilepsy. While AAV-based gene therapies offer therapeutic promise, systemic delivery to the brain is hindered by the blood– brain barrier (BBB). This study explores focused ultrasound (FUS) to transiently disrupt the BBB and enhance brain-wide delivery of a novel gene therapy to a mouse model of AS. A codon-optimized human UBE3A cDNA (hUBE3Aopt) AAV9 package was prepared. A robotic, image-guided focused ultrasound (FUS) system was employed to deliver treatment across one cerebral hemisphere. High-resolution volumetric images (24 MHz) were acquired and used for treatment planning (21 treatment spots 1×1 mm grid). AS mice (UBE3A deficient) were treated (n = 3) with a bolus of AAV (6 × 10¹³ vg/kg) followed by lipid microbubble infusion (2 × 108 #/mL at 34 μL/min) and FUS treatment (1 MHz, 467 kPa PNP (derated), 10k cycles, PRF 1 Hz, 10 seconds per spot). Two weeks post-treatment,brains were harvested for analysis. Immunohistological evaluation demonstrated robust UBE3A expression throughout the targeted hemisphere, confirming effective gene delivery. Treatment with FUS was well tolerated and dramatically increased UBE3A expression in the brains of adult mice. We were able to target and successfully treat large areas of the brain, opening the possibility to treat genetic disorders of the whole brain.