Engineered AAV Capsid Proteins for CNS Gene Therapy
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Solution Overview
Problem
Current recombinant adeno-associated virus (rAAV) gene therapy vectors face challenges in efficiently targeting and transducing cells in the central nervous system (CNS) due to the blood-brain barrier (BBB) obstruction.
Innovation Solution
Engineered recombinant AAV capsid proteins with peptides inserted in loop IV and/or loop VIII, specifically amino acid sequences selected from SEQ ID NOs: 1-6, to enhance transduction efficiency of neurons, astrocytes, microglia, and muscle cells, as well as increased permeation across the BBB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If parental AAV capsid proteins are used for gene therapy delivery, then the vectors can infect cells in culture and achieve some level of transduction, but they cannot efficiently cross the blood-brain barrier to deliver genes to CNS cells
Solution Approach 1:
The patent applies local quality by inserting specific peptide sequences (SEQ ID NOs: 1-6) into particular loops (loop IV and/or loop VIII) of the parental AAV capsid protein. This localized modification at specific positions (e.g., amino acid positions 440-447 in loop IV or 572-584 in loop VIII) enhances BBB permeation capability while maintaining the overall capsid structure and function, thereby resolving the contradiction between BBB crossing ability and CNS cell transduction efficiency.
Solution Approach 2:
The patent employs parameter changes by modifying the amino acid sequence of the capsid protein through peptide insertion. This changes the physical-chemical properties of the capsid surface, enabling it to interact with and cross the BBB. The modified capsid proteins (with peptides like GGHKAKGPRKLG, GGHAIYPRH, RTIGPSV, etc.) exhibit altered permeation parameters that allow efficient BBB traversal while preserving transduction functionality.
2Object-affected harmful factors
If the AAV capsid structure is modified to enhance BBB permeation, then transduction of CNS cells improves, but the complexity of capsid engineering increases
Solution Approach 1:
The patent reduces engineering complexity by applying local quality modifications rather than global capsid redesign. By inserting peptides into specific loops (IV and/or VIII) at defined positions, the invention achieves BBB permeation enhancement with minimal structural changes, avoiding the need to reengineer the entire capsid architecture.
Solution Approach 2:
The patent uses peptide sequences as intermediary elements that mediate between the capsid protein and the BBB. These peptides (SEQ ID NOs: 1-6) act as functional bridges that confer BBB-crossing capability without requiring complex capsid restructuring. The peptides serve as simple, modular intermediaries that can be inserted into standardized loop regions.
Data Source
AI summary
Provided herein are recombinant adeno-associated virus (AAV) capsid proteins, compositions (e.g., rAAV) comprising the capsid proteins, nucleic acids encoding the capsid proteins, and methods of making and using the capsid proteins.