Authors :
Presenting Author: Sophie Hill, PhD – Children's Hospital of Philadelphia
Andrew Nelson, BS – Harvard University
Matthew Simon, PhD – Jackson Laboratory
Holt Sakai, PhD – Harvard University
Jun Xie, PhD – University of Massachusetts
Alexander Sousa, PhD – Harvard University
Meirui An, BS – Harvard University
Guangping Gao, PhD – University of Massachusetts
Cathleen Lutz, PhD – Jackson Laboratory
David Liu, PhD – Harvard University
Ethan Goldberg, MD, PhD – CHOP
Rationale:
Dravet syndrome (DS) is a severe neurodevelopmental disorder characterized by drug-resistant epilepsy, temperature-sensitive seizures, developmental delay/intellectual disability, features of autism spectrum disorder, and a high incidence of sudden unexpected death in epilepsy. DS is caused by loss-of-function variants in SCN1A, which encodes the voltage-gated sodium channel ⍺ subunit Nav1.1. Current treatments for DS target symptoms but do not address the underlying cause. Here, we describe the use of adenine base editing (ABE) to directly correct SCN1AR613X, a recurrent mutation found in DS patients. Methods:
We identified ABE strategies to efficiently correct R613X in both mouse and human mutant cell lines. We used a dual-AAV9 approach to deliver an optimized ABE system to neonatal mice in an Scn1aR613X/+ mouse model that recapitulates key DS pathologies.Results:
AAV9-ABE treatment resulted in high editing efficiency in both genomic DNA (59%) and mRNA (97%) in mouse brain. Brain slice electrophysiology of parvalbumin-expressing neocortical GABAergic inhibitory neurons from ABE-treated mice revealed restored excitability and normalized action potential properties. AAV9-ABE also rescued key aspects of the mouse DS phenotype, protecting against temperature-sensitive seizures and rescuing mouse survival up to postnatal day 45. Conclusions:
These findings represent the direct correction of the underlying cause of DS and suggest the potential of precision genome editing treatments for DS and other neurodevelopmental disorders.
Funding:
Dravet Syndrome Foundation Postdoctoral Fellowship to S.F.H., Holt Family Epilepsy Neurogenetics Fellowship to S.F.H., Brody Family Foundation Postdoctoral Fellowship to S.F.H., NIGMS R35GM118062 to D.R.L, NHGRI RM1HG009490 to D.R.L, NINDS R01NS110869 to E.M.G., Dravet Syndrome Foundations Research Grant to E.M.G. and D.R.L., the Broad Institute Chemical Biology and Therapeutics Science program funds to D.R.L., and the HHMI (D.R.L.)