Antisense Oligonucleotide Stability via Naphthyl-Azo Terminal Modifications
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Solution Overview
Problem
Antisense oligonucleotides (ASOs) face challenges in maintaining binding affinity and nuclease resistance, particularly when targeting short RNA species like microRNAs, as existing modifications either compromise binding affinity or stability, and current nuclease-resistant modifications often hinder RNase H activation.
Innovation Solution
Incorporation of non-nucleotide modifying groups, such as napthyl-azo compounds, at terminal ends or between bases of ASOs to enhance binding affinity and nuclease resistance, allowing for improved potency and stability while retaining RNase H activation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If phosphorothioate groups are used to modify internucleotide linkages for nuclease resistance, then stability is improved, but binding affinity for target RNA is reduced
Solution Approach 1:
The patent applies local quality by placing non-nucleotide modifying groups (such as napthyl-azo compounds) at specific terminal positions (5' or 3' ends) or between specific bases of the ASO, rather than uniformly modifying the entire oligonucleotide. This localized modification approach allows the terminal regions to gain enhanced nuclease resistance and binding affinity while the central region maintains its ability to form RNase H-active heteroduplexes with the target RNA.
Solution Approach 2:
The patent employs composite materials by combining nucleotide units with non-nucleotide modifying groups (such as aromatic compounds like napthyl-azo groups) to create chimeric ASO structures. These composite structures integrate the nuclease resistance and binding affinity enhancement properties of the non-nucleotide groups with the RNase H activation capability of the nucleotide backbone, resolving the contradiction between stability and binding affinity.
2Strength
If chemical modifications are added to increase binding affinity, then potency is improved, but complexity of synthesis increases
Solution Approach 1:
The patent applies segmentation by dividing the ASO into distinct functional regions: terminal regions containing non-nucleotide modifying groups for enhanced binding and stability, and central regions with unmodified or differently modified nucleotides for RNase H activity. This segmented approach allows each region to be optimized independently, improving binding affinity without requiring complex modifications throughout the entire molecule.
Solution Approach 2:
The patent utilizes parameter changes by modifying specific physical and chemical parameters (such as adding aromatic non-nucleotide groups) at terminal positions to enhance binding affinity and nuclease resistance, while keeping the core nucleotide sequence and central region parameters unchanged to maintain RNase H activation capability and simplify synthesis.
3Strength
If ASO length is increased to improve binding affinity, then potency is improved, but susceptibility to endonuclease degradation increases
Solution Approach 1:
The patent applies preliminary anti-action by incorporating non-nucleotide modifying groups at terminal positions that proactively block endonuclease attack sites before degradation can occur. These terminal modifications create a protective barrier that prevents harmful enzymatic cleavage, allowing the use of longer ASO sequences for improved binding affinity without proportionally increasing susceptibility to endonuclease degradation.
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
The use of napthyl-azo modifications in ASOs increases binding affinity and nuclease resistance, leading to enhanced potency and stability, effectively reducing target RNA levels without compromising RNase H activity, even for short RNA targets.
Implementation Method 1
antisense oligonucleotides (ASOs) are synthetic nucleic acids that bind to a complementary target
Implementation Method 2
the modifications are used to improve binding affinity
Implementation Method 3
provide protection from nuclease degradation
Implementation Method 4
RNase H degrades the RNA portion of the heteroduplex molecule
Data Source
AI summary
The invention pertains to modifications for antisense oligonucleotides, wherein the modifications are used to improve stability and provide protection from nuclease degradation. The modifications could also be incorporated into double-stranded nucleic acids, such as synthetic siRNAs and miRNAs.