DUX4 Transcript Knockdown with Antisense 2′-O-Methoxyethyl Gapmers for the Treatment of Facioscapulohumeral Muscular Dystrophy

Abstract

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disorder characterized by a progressive, asymmetric weakening of muscles, starting with those in the upper body. It is caused by aberrant expression of the double homeobox protein 4 gene (DUX4) in skeletal muscle. FSHD is currently incurable. We propose to develop a therapy for FSHD using antisense 2'-O-methoxyethyl (2'-MOE) gapmers, to knock down DUX4 mRNA expression. Using immortalized patient-derived muscle cells and local intramuscular injections in the FLExDUX4 FSHD mouse model, we showed that our designed 2'-MOE gapmers significantly reduced DUX4 transcript levels invitro and invivo, respectively. Furthermore, invitro, we observed significantly reduced expression of DUX4-activated downstreamtargets, restoration of FSHD signature genes by RNA sequencing, significant improvements in myotube morphology, and minimal off-target activity. This work facilitates the developmentof a promising candidate therapy for FSHD and lays down the foundation for invivo systemic treatment studies.