Mixed-backbone oligonucleotides as second-generation antisense agents with reduced phosphorothioate-related side...

Area of Science:

• Oligonucleotide chemistry
• Medicinal chemistry
• Biotechnology

Background:

• Phosphorothioate oligodeoxynucleotides (PS-ODNs) are widely used as antisense agents.
• PS-ODNs can exhibit prolonged partial thromboplastin time, a potential side effect.
• Nuclease degradation limits the in vivo efficacy of unmodified oligonucleotides.

Purpose of the Study:

• To develop novel antisense agents with improved pharmacokinetic and pharmacodynamic properties.
• To evaluate the efficacy and safety profile of mixed-backbone oligonucleotides (MB-ONs).
• To compare MB-ONs with PS-ODNs regarding target affinity, nuclease stability, and hemostatic effects.

Main Methods:

• Synthesis of mixed-backbone oligonucleotides with alternating phosphorothioate and phosphodiester linkages in the 2'-O-methylribonucleoside segment.
• Assessment of binding affinity to complementary RNA targets using hybridization assays.
• Evaluation of nuclease stability in vitro (using serum or nucleases) and in vivo.
• Measurement of partial thromboplastin time in preclinical models.

Main Results:

• MB-ONs exhibited significantly increased binding affinity to complementary targets compared to PS-ODNs.
• The modified oligonucleotides demonstrated enhanced stability against nucleases, both in vitro and in vivo.
• A notable reduction in the prolongation of partial thromboplastin time was observed with MB-ONs.

Conclusions:

• Mixed-backbone oligonucleotides represent a promising class of antisense agents.
• These novel compounds offer improved target affinity and nuclease resistance.
• The reduced impact on coagulation parameters suggests a favorable safety profile for therapeutic applications.