Synthesis and antisense properties of 2'-O-(2S-methoxypropyl)-RNA-modified gapmer antisense oligonucleotides

Area of Science:

• Oligonucleotide chemistry
• Molecular biology
• Drug discovery

Background:

• Second-generation antisense oligonucleotides (ASOs) are crucial for gene silencing.
• Enhancing ASO hydrophobicity may improve their efficacy, particularly in muscle tissue.
• The 2'-O-(2S-methoxypropyl)-RNA (2S-MOP) modification offers increased hydrophobicity.

Purpose of the Study:

• To evaluate the antisense properties and efficacy of 2S-MOP modified ASOs.
• To determine if increased hydrophobicity enhances ASO activity in muscle.
• To synthesize 2S-MOP modified nucleosides and oligonucleotides.

Main Methods:

• Multi-gram scale synthesis of 2S-MOP phosphoramidite and nucleosides.
• Automated DNA synthesis of 2S-MOP modified oligonucleotides.
• In vivo evaluation in Balb-c mice to assess mRNA reduction.

Main Results:

• 2S-MOP modified oligonucleotides demonstrated comparable duplex thermal stability to 2'-O-methoxyethyl RNA (MOE) modified ASOs.
• In vivo studies showed significant reduction in scavenger receptor B1 (Srb1) and phosphatase and tensin homologue (PTEN) mRNA levels in liver and muscle.
• The synthesis of 2S-MOP modified nucleosides was achieved on a multi-gram scale.

Conclusions:

• 2S-MOP modification is a viable strategy to enhance ASO hydrophobicity and activity.
• These findings support the potential of 2S-MOP ASOs for therapeutic applications targeting muscle and liver gene expression.
• The developed synthetic routes enable scalable production of 2S-MOP modified oligonucleotides.