4′-Modified dsRNA Agents for Nuclease Stability and Silencing
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Solution Overview
Problem
Current RNAi duplex agents face challenges in achieving effective gene silencing with stability and reduced off-target effects, as well as immunomodulating effects, limiting their therapeutic efficacy in treating diseases.
Innovation Solution
The development of 4′-modified oligonucleotides for RNA interference, specifically incorporating 4′-modified nucleosides into the sense and antisense strands of dsRNA agents, which can conjugate with GalNAc derivatives, enhancing gene silencing activity, stability, and reducing off-target effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If chemical modifications are incorporated into RNAi duplex agents, then stability to nucleases and therapeutic characteristics are improved, but gene silencing efficacy may be compromised
Solution Approach 1:
The patent applies local quality by placing 4'-modified nucleosides specifically at the 3' terminal positions of the sense and antisense strands, rather than uniformly throughout the sequence. This localized modification provides nuclease resistance at the vulnerable terminal regions while preserving the unmodified internal regions that are critical for RISC loading and gene silencing activity.
Solution Approach 2:
The patent creates composite RNAi duplex structures by combining modified terminal nucleosides (providing stability) with unmodified internal nucleotides (providing biological activity). This composite approach allows the molecule to simultaneously exhibit both nuclease resistance and effective gene silencing properties.
2Reliability
If modifications are made to enhance gene silencing activity, then knockdown efficacy is improved, but off-target effects and immunomodulation may increase
Solution Approach 1:
The patent applies local quality by restricting chemical modifications to only the terminal nucleosides rather than throughout the entire sequence. This localized approach provides protective benefits at the ends while keeping the gene-silencing-critical internal regions unmodified, thereby maintaining specificity and reducing off-target effects.
Solution Approach 2:
The patent converts the potential harm of chemical modifications (which can cause off-target effects and immunomodulation) into benefit by strategically placing them only where needed for stability (terminal positions), while leaving the biologically active regions unmodified. This transforms a potentially harmful global modification into a beneficial localized protection.
Data Source
AI summary
One aspect of the present invention relates to double-stranded RNAi (dsRNA) duplex agent capable of inhibiting the expression of a target gene in vivo. The dsRNA duplex comprises one or more 4′-modifications in one or both strand. Other aspects of the invention relates to pharmaceutical compositions comprising these dsRNA agents suitable for in vivo therapeutic use, and methods of inhibiting the expression of a target gene by administering these dsRNA agents, e.g., for the treatment of various disease conditions.