Abasic siNA Antisense Modifications Reduce Off-Target Effects
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Solution Overview
Problem
RNA interference (RNAi) techniques, particularly siRNA-mediated approaches, face challenges due to off-target effects, where siRNA molecules inadvertently regulate non-target genes, leading to unwanted gene knockdowns and reduced specificity, especially through participation in miRNA pathways.
Innovation Solution
The introduction of abasic modifications within the first 8 nucleotide positions of the 5' region of the antisense strand in siNA molecules reduces off-target effects by decreasing the binding strength of the antisense strand to non-target sequences, thereby enhancing the specificity of the siNA for the target gene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If siRNA molecules are used for gene silencing, then gene knockdown efficiency is improved, but off-target effects increase leading to reduced specificity
Solution Approach 1:
The patent applies local quality by introducing abasic modifications specifically at positions 2-8 of the antisense strand, while leaving other positions unchanged. This localized modification approach allows the siRNA to maintain its gene silencing function through the intact seed region and binding interface, while the modified positions specifically reduce off-target effects by preventing non-specific interactions with miRNA pathways and other cellular components.
2Object-affected harmful factors
If abasic modifications are introduced in the first 8 nucleotide positions of the antisense strand, then off-target effects are reduced, but binding strength to target sequences may be weakened
Solution Approach 1:
The patent applies parameter changes by modifying the chemical nature of nucleotides at specific positions (2-8) of the antisense strand, replacing them with abasic modifications that have altered binding properties. This parameter change selectively reduces affinity for non-target sequences involved in off-target effects, while the overall binding strength to the intended target is preserved through the cumulative effect of remaining complementary base pairs at other positions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively reduces off-target effects while maintaining the ability to efficiently downregulate target genes, allowing for increased concentration of siNA molecules to achieve desired knockdown levels without significant impact on target sequence binding.
Implementation Method 1
the antisense strand has sufficient complementarity to the target sequence to mediate RNA interference
Implementation Method 2
RNA interference (RNAi) works by silencing a gene through homologous short interfering dsRNAs (for example siRNAs), which trigger the destruction of the corresponding mRNA by the RNA-induced silencing complex (RISC)
Data Source
AI summary
The present invention pertains to the use of at least one abasic modification within the first 8 nucleotide positions of the 5′ region of the antisense strand of a small interfering nucleic acid (siNA) molecule for reducing off-target effects. Provided are suitable modified siNAs, compositions and methods for producing respective siNAs, as well as kits comprising respective siNAs.