Modified siRNA Duplex Composition for Stable Gene Silencing
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Solution Overview
Problem
Existing double-stranded oligonucleotides face challenges in maintaining optimal gene-silencing activity due to variations in activity or loss of activity caused by different modifications, particularly with siRNA duplexes comprising 2'-OMe and 2'-F modifications.
Innovation Solution
A double-stranded oligonucleotide with specific sterically bulky and disubstituted modifications at defined positions in the sense and antisense strands, represented by Formula (I), along with optional phosphorothioate linkages and overhang regions, to enhance stability and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If different modifications (2'-OMe, 2'-F, phosphorothioate) are applied to stabilize siRNA in serum, then serum stability is improved, but gene-silencing activity varies or is lost
Solution Approach 1:
The patent applies different modification types at specific positions within the dsRNA structure. 2'-OMe modifications are placed at certain positions while 2'-F modifications are placed at other positions, with phosphorothioate linkages connecting them. This local differentiation allows each modification to contribute its optimal property (stability or activity) at the appropriate location, resolving the contradiction between overall stability and maintained gene-silencing activity.
Solution Approach 2:
The invention creates a composite modified dsRNA structure that integrates multiple modification types (2'-OMe, 2'-F, and phosphorothioate) into a single functional molecule. This composite approach allows the molecule to simultaneously exhibit enhanced serum stability from the modified nucleotides while maintaining gene-silencing activity through the coordinated action of different modifications at strategic positions.
2Productivity
If MOE modifications are applied to modulate siRNA lipophilicity for efficient delivery, then delivery efficiency is improved, but siRNA activity is impaired
Solution Approach 1:
The patent limits MOE-like modifications (2'-OMe and 2'-F) to specific positions within the dsRNA rather than applying them throughout the entire molecule. This localized application provides sufficient lipophilicity modulation for efficient delivery while preserving the essential activity-determining regions of the siRNA, thereby avoiding the activity impairment that occurs with extensive MOE modification.
Solution Approach 2:
The invention carefully controls the number and position of lipophilic modifications to optimize the balance between delivery efficiency and activity. By adjusting the modification pattern (which positions have 2'-OMe or 2'-F) and the length of phosphorothioate linkages, the patent tunes the lipophilicity parameter to achieve efficient delivery without excessive activity loss.
Data Source
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AI summary
Provided are a preparation method for a modified double-stranded oligonucleotide, an oligonucleotide conjugate or a composition, and use. Provided is a modified double-stranded oligonucleotide. Specific modification of a single site or a plurality of sites is carried out on a specific site of a sense strand and/or an antisense strand of an oligonucleotide, so that the modified oligonucleotide can have good pharmaceutical activity and have good application prospects in the development of RNA interference (RNAi)-based drugs.