Delivery of A Chemically Modified Noncoding RNA Domain Improves Dystrophic Myotube Function

Area of Science:

• Molecular Biology
• RNA Therapeutics
• Muscle Physiology

Background:

• Fast-twitch muscle fibers are vulnerable in aging and muscular dystrophies.
• The long noncoding RNA CYTOR promotes fast-twitch myogenesis.
• Targeting CYTOR may offer therapeutic benefits for muscle pathologies.

Purpose of the Study:

• Identify a functional domain within human CYTOR.
• Optimize RNA delivery of this domain for therapeutic applications.
• Evaluate the efficacy of CYTOR exon 2 in preclinical models of muscular dystrophy.

Main Methods:

• Exogenous delivery of CYTOR exon 2 into human primary myoblasts.
• Chemical modification of CYTOR exon 2 RNA (CYTOR^{exon2, m1ΨU}) to enhance stability and reduce immunogenicity.
• Administration of CYTOR^{exon2, m1ΨU} via viral or chemical methods in various cell types and disease models.

Main Results:

• Exogenous CYTOR exon 2 successfully recapitulated the effects of full-length CYTOR on myogenic differentiation.
• Chemically modified CYTOR^{exon2, m1ΨU} demonstrated improved stability and reduced immunogenicity.
• CYTOR^{exon2, m1ΨU} administration promoted myogenic maturation and improved disease characteristics in dystrophic muscle cells, including calcium handling and mitochondrial function.

Conclusions:

• CYTOR exon 2 is the functional domain responsible for promoting fast-twitch myogenesis.
• Chemically modified CYTOR exon 2 is a viable candidate for RNA-based therapeutics targeting muscle pathologies.
• Targeting specific RNA domains represents a promising strategy for next-generation RNA therapeutics.