Engineered AAV Capsids for Tissue-Specific Gene Delivery
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Solution Overview
Problem
Existing AAV vectors face challenges such as promiscuous viral tropism, limited ability to circumvent biological barriers, and high prevalence of pre-existing neutralizing antibodies, which hinder their efficacy in targeted gene delivery.
Innovation Solution
Development of AAV capsid variants with engineered peptides in hypervariable and surface-exposed loops, combined with silent mutations, localization signals, barcodes, and reporter proteins, to enhance tissue specificity and delivery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If AAV capsid proteins are used for gene delivery, then gene delivery capability is achieved, but tissue specificity is poor due to promiscuous viral tropism
Solution Approach 1:
The patent applies local quality by inserting peptides specifically into hypervariable and surface-exposed loops of the AAV capsid protein structure. These localized modifications at specific surface regions (rather than global changes) alter the capsid's interaction properties with target tissues, enabling selective binding to desired cell types while maintaining overall capsid integrity and function.
Solution Approach 2:
The patent employs parameter changes by introducing silent mutations in the nucleic acid sequence that do not alter the amino acid sequence but change physical or chemical properties of the capsid. These mutations can affect capsid stability, conformation, or surface properties, thereby modifying tissue tropism and delivery efficiency without changing the fundamental capsid structure.
2Productivity
If AAV vectors are used for gene delivery, then gene delivery is achieved, but delivery efficiency is reduced due to pre-existing neutralizing antibodies
Solution Approach 1:
The patent applies inversion by fundamentally changing the capsid surface properties through peptide insertions and mutations, creating a novel capsid variant that is not recognized by pre-existing antibodies against wild-type AAV. This inverse approach modifies the antigenic surface to evade immune detection while maintaining or enhancing delivery function.
Solution Approach 2:
The patent creates composite capsid structures by combining the native AAV capsid protein framework with inserted peptide sequences. This composite approach integrates foreign peptide elements into the capsid structure, generating a hybrid protein that retains AAV's beneficial properties while acquiring new characteristics that circumvent neutralizing antibodies.
3Adaptability or versatility
If AAV capsid variants are engineered with peptides and mutations, then tissue specificity is improved, but capsid structure complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the capsid modification strategy into distinct functional elements: hypervariable loops for target recognition, surface-exposed regions for peptide insertion, and flanking sequences for silent mutations. This segmented approach allows independent optimization of each region's function while maintaining overall capsid assembly and stability.
Data Source
AI summary
The present disclosure provides methods and compositions to develop AAV capsids with a desired characteristic compared to a natural AAV serotype. These capsids are useful, for example, for the delivery of genome engineering molecules and gene therapy molecules for the treatment of a subject in need thereof.