A high-fidelity RNA-targeting Cas13 restores paternal Ube3a expression and improves motor functions in Angelman syndrome mice.

Angelman syndrome (AS) is a rare neurodevelopmental disorder caused by loss of function mutations in maternally expressed UBE3A. No gene-specific treatment is available for patients so far. Although intact and transcriptionally active, paternally inherited UBE3A is silenced by elongation of antisense long noncoding RNA UBE3A-ATS in neurons. Here, we demonstrated that RNA targeting of paternal Ube3a-ATS with a high-fidelity CRISPR-Cas13 (hfCas13x.1) system could restore Ube3a expression to similar levels as that of maternal Ube3a in the cultured mouse neurons. Furthermore, injection into lateral ventricles with neuron-specific hSyn1 promoter-driven hfCas13x.1 packaged in adeno-associated virus (AAV-PHP.eb) could restore paternal Ube3a expression in cortex and hippocampus of neonatal AS mice for up to 4 months after treatment. Behavioral tests showed that expression of paternal Ube3a significantly alleviated AS-related symptoms, including obesity and motor function. Our results suggested that hfCas13x.1-mediated suppression of the Ube3a-ATS lncRNA potentially serves as a promising targeted intervention for AS.