Title

Allele-specific RNA interference prevents neuropathy in Charcot-Marie-Tooth disease type 2D mouse models.

Document Type

Article

Publication Date

12-2-2019

Keywords

JMG

JAX Source

J Clin Invest 2019 Dec 2; 129(12):5568-5583

PMID

31557132

DOI

https://doi.org/10.1172/JCI130600

Grant

Jackson Laboratory Director's Innovation Fund, NS054154,OD020351,NS105116,MDA 351564,NS098540,NS100328, CA034196

Abstract

Gene therapy approaches are being deployed to treat recessive genetic disorders by restoring the expression of mutated genes. However, the feasibility of these approaches for dominantly inherited diseases - where treatment may require reduction in the expression of a toxic mutant protein resulting from a gain-of-function allele - is unclear. Here we show the efficacy of allele-specific RNAi as a potential therapy for Charcot-Marie-Tooth disease type 2D (CMT2D), caused by dominant mutations in glycyl-tRNA synthetase (GARS). A de novo mutation in GARS was identified in a patient with a severe peripheral neuropathy, and a mouse model precisely recreating the mutation was produced. These mice developed a neuropathy by 3-4 weeks of age, validating the pathogenicity of the mutation. RNAi sequences targeting mutant GARS mRNA, but not wild-type, were optimized and then packaged into AAV9 for in vivo delivery. This almost completely prevented the neuropathy in mice treated at birth. Delaying treatment until after disease onset showed modest benefit, though this effect decreased the longer treatment was delayed. These outcomes were reproduced in a second mouse model of CMT2D using a vector specifically targeting that allele. The effects were dose dependent, and persisted for at least 1 year. Our findings demonstrate the feasibility of AAV9-mediated allele-specific knockdown and provide proof of concept for gene therapy approaches for dominant neuromuscular diseases.

Comments

At The Jackson Laboratory, Bonnie Lyons, Rosilinda Dotti, Kathy Miers, Peter Finger, and the In Vivo Pharmacology Service provided training, consultation, technical assistance, and infrastructure.

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