Efficient and persistent splice switching by systemically delivered LNA oligonucleotides in mice

Area of Science:

• Molecular Biology
• Genetics
• Pharmacology

Background:

• Alternative splicing is crucial for gene expression and can be dysregulated in disease.
• Locked nucleic acid (LNA) oligonucleotides are chemically modified nucleic acids with enhanced binding affinity.
• Modulating splicing offers a therapeutic strategy for genetic disorders.

Purpose of the Study:

• To evaluate the in vivo efficacy of LNA oligonucleotides in correcting aberrant pre-mRNA splicing.
• To determine the biodistribution and potency of LNA splice-switching oligonucleotides (SSOs).
• To assess the safety and duration of action of LNA SSOs for therapeutic applications.

Main Methods:

• Transgenic mice expressing a modified EGFP pre-mRNA with an aberrant intron (IVS2-654) were used.
• Intraperitoneal injections of LNA SSO-654 were administered to assess splice correction.
• Organ distribution, EC50 determination, oral dosing, and toxicity studies were performed.

Main Results:

• LNA SSO-654 effectively corrected aberrant splicing of EGFP pre-mRNA in the liver, colon, and small intestine.
• The LNA SSO demonstrated high potency (EC50 of 3 mg/kg in the liver) and organ-specific biodistribution.
• Therapeutic effects persisted for up to 29 days with no observed liver toxicity, and oral administration showed efficacy.

Conclusions:

• LNA oligonucleotides are potent and effective modulators of alternative splicing in vivo.
• The LNA backbone confers sequence- and organ-specific biodistribution, enhancing therapeutic potential.
• LNA SSOs represent a promising, safe, and long-acting approach for diseases treatable by splicing manipulation.