Muscle-Targeting AAV Capsids for Lower-Dose Gene Delivery
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Solution Overview
Problem
Conventional recombinant adeno-associated viruses (rAAVs) exhibit limited cell tropism, requiring high doses for effective delivery to non-liver tissues like nervous and cardiac muscle, leading to liver toxicity and manufacturing challenges, and species-specific transduction efficiency varies, making preclinical mouse studies less predictive for human results.
Innovation Solution
Engineered AAV vectors with muscle-targeting moieties, such as RGD motifs, are developed to enhance specificity and efficiency for muscle cell delivery, using n-mer motifs inserted into viral capsids to improve transduction efficiency and reduce immunogenicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rAAVs with natural capsid variants are used for systemic delivery, then liver transduction is achieved, but transduction efficiency in other tissues (nervous system, skeletal muscle, cardiac muscle) is limited
Solution Approach 1:
The patent applies local quality by engineering specific regions of the AAV capsid protein to exhibit distinct binding properties. By modifying particular amino acid residues or inserting peptide motifs at specific locations on the capsid surface, the invention creates localized interaction zones that selectively recognize and bind to receptors on target cell surfaces (such as muscle cells), while leaving other regions of the capsid intact for maintaining structural integrity and general viral function.
2Reliability
If large doses of conventional rAAV are administered to achieve effective transduction in non-liver tissues, then transduction efficiency improves, but liver toxicity increases
Solution Approach 1:
The patent employs an intermediary approach by introducing engineered capsid variants that act as mediators between the viral vector and target cells. These modified capsids serve as specialized interfaces that selectively interact with receptors on non-liver tissue cells (such as muscle-specific receptors), thereby directing the viral vector to the intended target while avoiding non-specific uptake by liver cells and reducing hepatotoxicity associated with high-dose conventional rAAV administration.
3Reliability
If conventional rAAV dosing is used to treat adult patients, then therapeutic effect may be achieved, but manufacturing sufficient amounts becomes extremely challenging
Solution Approach 1:
The patent applies parameter changes by systematically modifying the capsid protein's amino acid sequence, charge distribution, and surface properties to enhance transduction efficiency. By altering parameters such as capsid surface charge, hydrophobicity, and receptor-binding affinity through site-directed mutagenesis or peptide insertion, the invention achieves higher transduction potency at lower doses, thereby reducing the total viral vector quantity required for treatment and making large-scale manufacturing for adult patient dosing more feasible.
4Productivity
If preclinical studies in mice are conducted to evaluate rAAV capsids, then initial data is obtained, but results do not accurately reflect outcomes in primates and humans due to species-specific differences
Solution Approach 1:
The patent employs universality by designing capsid variants with conserved binding mechanisms that function across multiple species. By engineering capsids that recognize evolutionarily conserved receptor structures or cellular entry pathways shared between mice, primates, and humans, the invention creates a multi-functional viral vector system whose transduction mechanism remains consistent across species barriers, thereby improving the predictive accuracy of preclinical mouse studies for human clinical outcomes.
Data Source
AI summary
Described herein are targeting moieties that can be capable of specifically targeting muscle cells and can include an n-mer motif. In some embodiments, the n-mer motif contains an RGD motif. Also described herein are vector systems, particles, polypeptides that can encode and/or contain one or more targeting moieties. Also described herein are methods of delivering a cargo to a cell, such as a muscle cell, using one or more of the targeting moieties described herein.