Asymmetric Oligonucleotide Modifications for Uptake and Stability
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Solution Overview
Problem
There is a need for self-delivering oligonucleotides that efficiently enter the RNA-Induced Silencing Complex (RISC), minimize immune response and off-target effects, achieve efficient cellular uptake without formulation, and exhibit specific tissue distribution.
Innovation Solution
The development of nearly fully 2′-O-methyl modified, asymmetric siRNAs with non-2′-O-methyl modifications at specific positions, such as 2′-fluoro modifications at positions 2 and 14 from the 5′ end of the antisense strand, to enhance efficacy, uptake, and tissue distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fully 2'-O-methyl modified oligonucleotides are used, then nuclease resistance and stability are improved, but cellular uptake and RISC entry efficiency deteriorate
Solution Approach 1:
The patent applies local quality by introducing non-2'-O-methyl modifications (such as 2'-fluoro or 2'-H) at specific positions (positions 2 and 14 from the 5' end of the antisense strand) while maintaining 2'-O-methyl modifications at all other positions. This localized modification strategy preserves nuclease resistance across the majority of the oligonucleotide while creating specific regions that enhance cellular uptake and RISC entry efficiency, thereby resolving the contradiction between stability and productivity.
2Object-affected harmful factors
If fully 2'-O-methyl modified oligonucleotides are used, then immune response reduction is improved, but off-target effects and efficacy deteriorate
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through strategic placement of non-2'-O-methyl modifications at positions 2 and 14 of the antisense strand. These localized modifications maintain the overall low immunogenicity profile of fully modified oligonucleotides while creating specific structural features that enhance target recognition and silencing efficacy, thus reducing harmful effects without compromising reliability.
Solution Approach 2:
The patent applies asymmetry by creating an asymmetric modification pattern where positions 2 and 14 of the antisense strand differ from the rest of the oligonucleotide sequence. This asymmetric design optimizes the balance between immune response reduction and efficacy enhancement, as the modified regions provide structural features that improve target binding while the majority 2'-O-methyl modifications maintain low immunogenicity.
3Stability of the object's composition
If alternating chemically-modified nucleotides are used, then nuclease resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent simplifies manufacturing by applying local quality rather than alternating modifications throughout the sequence. By concentrating non-2'-O-methyl modifications at only two specific positions (2 and 14) in the antisense strand, the synthesis process requires handling fewer different nucleotide types compared to alternating patterns, thereby reducing manufacturing complexity while maintaining high nuclease resistance through the predominant 2'-O-methyl modifications.
Data Source
AI summary
Novel oligonucleotides that are fully chemically stabilized are provided. Methods of using oligonucleotides that are fully chemically stabilized are also provided.