An antisense method for efficient exon skipping and its application to Duchenne muscular dystrophy

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• Antisense-mediated exon skipping is a strategy to treat Duchenne muscular dystrophy (DMD) by restoring the dystrophin (DMD) reading frame.
• Challenges in designing effective antisense oligonucleotides (ASOs) have limited clinical translation of this therapeutic approach.

Purpose of the Study:

• To develop a robust bipartite ASO design, termed 5' splice site decoy (5D)-ASO, to enhance exon skipping efficiency.
• To evaluate the efficacy and safety of 5D-ASOs for Duchenne muscular dystrophy (DMD) treatment.

Main Methods:

• Designed a bipartite ASO (5D-ASO) incorporating a tail sequence to enhance splicing repression at the 5' splice site of target exons.
• Tested 5D-ASOs targeting DMD exon 51 in mouse models of Duchenne muscular dystrophy.
• Assessed dystrophin expression, muscle function, and toxicity in preclinical models and non-human primates.

Main Results:

• The 5D-ASO design significantly enhanced exon skipping compared to conventional ASOs.
• Targeting DMD exon 51 with an 8-nt tail 5D-ASO restored dystrophin expression and improved muscle function in mouse models without apparent toxicity.
• The lead 5D-ASO candidate demonstrated significant exon-skipping activity and a favorable safety profile in monkeys.

Conclusions:

• The 5D-ASO platform technology offers a promising strategy for developing effective RNA-targeted therapeutics.
• This approach holds potential for treating Duchenne muscular dystrophy and other genetic disorders by enhancing exon skipping.
• The 5D-ASO design represents a valuable advancement in antisense oligonucleotide technology for therapeutic applications.