AAV Capsid Mutations for Tissue Targeting
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Solution Overview
Problem
Current recombinant adeno-associated virus (rAAV) vectors face limitations due to low transduction efficiency and restricted tissue tropisms, making them less effective for therapeutic gene delivery, and there is a concern about translating non-human derived AAV serotypes for clinical use.
Innovation Solution
Development of novel AAV variants with amino acid variations in capsid proteins that enhance tissue targeting properties, such as AAV2, AAV2/3 hybrid, and AAV8, which are specifically designed to target human tissues like hepatocytes, central nervous system cells, ocular tissue, and other specific tissues, using methods like high-throughput sequencing to identify these variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If currently available rAAV vectors are used, then gene delivery can be achieved, but transduction efficiency is low and tissue tropism is restricted
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of capsid proteins through site-directed mutagenesis. Specific amino acid substitutions (e.g., AAV2: K293R, E296K, R304E; AAV8: K293R, E296K, R304E) alter the physical-chemical properties of the capsid surface, enabling enhanced binding affinity to human tissue receptors and improved transduction efficiency across diverse tissue types.
Solution Approach 2:
The patent creates composite capsid structures by generating hybrid AAV serotypes that combine elements from different parent serotypes. Examples include AAV2/3 hybrids (combining AAV2 and AAV3 capsid regions) and AAV8/9 hybrids, which integrate advantageous properties from each parent to achieve broad tissue tropism and high transduction efficiency simultaneously.
2Reliability
If non-human derived AAV serotypes are used, then gene delivery capability is achieved, but clinical translation safety is compromised
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions at specific locations on the capsid protein surface while preserving the overall capsid structure and function. These localized changes (e.g., residues 293-304 in VP1) confer human tissue specificity without introducing foreign epitopes that would trigger immune responses, thus maintaining safety for clinical translation.
Solution Approach 2:
The patent creates human-optimized copies of non-human AAV serotypes by generating capsid variants with amino acid sequences that mimic human AAV properties. These engineered capsids (e.g., AAV2.7, AAV8.7 variants) replicate the safe profile of human-derived AAVs while retaining the enhanced gene delivery capabilities of non-human parent serotypes.
3Adaptability or versatility
If amino acid variations in capsid proteins are introduced, then tissue targeting properties are enhanced, but vector complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the capsid protein into functional domains and introducing mutations only in specific regions (e.g., the P1-P3 loop region containing residues 293-304). This segmented approach allows precise optimization of tissue targeting properties while leaving other critical capsid functions unchanged, thereby minimizing overall vector complexity.
Solution Approach 2:
The patent creates universal capsid variants that can target multiple tissue types through single or dual amino acid substitutions. These engineered capsids (e.g., AAV2-KRE, AAV8-KRE variants) exhibit multi-functional tissue tropism for liver, lung, brain, and other tissues, reducing the need for multiple different vector constructs and simplifying the overall vector system.
Data Source
AI summary
The disclosure in some aspects relates to recombinant adeno-associated viruses having distinct tissue targeting capabilities. In some aspects, the disclosure relates to gene transfer methods using the recombinant adeno-associated viruses. In some aspects, the disclosure relates to isolated AAV capsid proteins and isolated nucleic acids encoding the same.