Engineered Guide RNA Chemical Modifications for RNA Editing Specificity
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Solution Overview
Problem
Current genetic editing methods using polynucleotides for recruiting nucleic acid editing entities face challenges such as off-target editing, degradation, and limited efficiency and specificity, particularly when targeting RNA molecules, which can lead to ineffective treatment of diseases.
Innovation Solution
Engineered guide RNAs with chemical modifications and targeting domains are developed to hybridize with target RNAs, recruiting RNA editing entities like ADAR or APOBEC to perform site-specific editing, enhancing specificity and resistance to nuclease digestion while reducing immunogenicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard polynucleotides are used for recruiting nucleic acid editing entities, then the editing process can be initiated, but off-target editing occurs and specificity is limited
Solution Approach 1:
The patent applies local quality by introducing chemical modifications at specific positions within the guide RNA molecule. Different regions of the guide RNA receive different modifications - for example, 2'-O-methyl modifications at certain positions while other regions remain unmodified or receive different modifications. This localized differentiation enhances binding specificity to the target RNA sequence while reducing off-target effects, as the modified regions provide selective stability and recognition properties only where needed.
Solution Approach 2:
The patent employs parameter changes by systematically varying chemical modification types (2'-O-methyl, phosphorothioate, locked nucleic acid), modification positions, and modification densities across different guide RNA designs. These parameter adjustments optimize the balance between guide RNA stability, target binding affinity, and specificity. For instance, increasing 2'-O-methyl modifications enhances nuclease resistance and binding stability, while strategic placement of mismatches with specific modifications fine-tunes target recognition precision.
2Productivity
If guide RNAs are designed to bind tightly to target RNA, then editing efficiency increases, but the guide RNAs become more susceptible to nuclease digestion and degradation
Solution Approach 1:
The patent applies preliminary action by pre-modifying the guide RNA with chemical modifications before it engages in target binding. The 2'-O-methyl and phosphorothioate modifications are incorporated into the guide RNA structure in advance, creating a protected configuration that resists nuclease digestion. This pre-protection ensures that the guide RNA maintains its integrity and binding capability throughout the editing process, allowing sustained high efficiency without degradation.
Solution Approach 2:
The patent uses composite materials by combining multiple chemical modification types within a single guide RNA molecule. The guide RNA becomes a composite structure with 2'-O-methyl modified nucleotides, phosphorothioate backbone modifications, and potentially locked nucleic acid components. This composite architecture provides both enhanced stability against nucleases and maintained or improved target binding affinity, as different modification types contribute complementary protective and binding properties.
3Stability of the object's composition
If chemical modifications are added to guide RNAs to improve stability, then resistance to degradation increases, but immunogenicity may increase
Solution Approach 1:
The patent applies local quality by strategically limiting chemical modifications to specific regions of the guide RNA rather than uniform modification throughout. For example, 2'-O-methyl modifications are applied at positions that enhance stability and binding, while regions that might trigger immune recognition are left unmodified or minimally modified. This localized approach maintains the necessary stability improvements while minimizing immunogenicity by preserving native RNA structures in immune-sensitive regions.
Solution Approach 2:
The patent employs parameter changes by systematically adjusting the density and distribution of chemical modifications. Rather than using high levels of uniform modification that would maximize stability but also maximize immunogenicity, the patent optimizes modification density to achieve sufficient stability while maintaining lower overall modification levels in regions prone to immune recognition. This parameter optimization balances stability enhancement with immunogenicity reduction.
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 engineered guide RNAs demonstrate increased efficiency and specificity in RNA editing, improved stability, and reduced off-target effects, facilitating effective treatment of diseases by precisely modifying target RNA molecules.
Implementation Method 1
the targeting domain hybridizes to a target RNA when administered to a subject, thereby forming a complex that recruits an RNA editing entity
Implementation Method 2
the RNA editing entity, when associated with the engineered guide RNA and the target RNA, performs a targeted editing of a base of a nucleotide of the target RNA
Data Source
AI summary
Described herein are compositions for targeting and editing genomes. Also described herein are methods for targeting and editing genomes utilizing the compositions in the instant disclosure.