Modified AAV Vectors with Surface Saccharides for CNS Delivery
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Solution Overview
Problem
Current adeno-associated virus (AAV) vectors face challenges in achieving widespread transduction in the central nervous system (CNS) due to limited blood-brain barrier penetration, high off-target effects, and immune response, requiring multiple invasive injections and large doses, which are not scalable for human treatment and are hindered by pre-existing immunity.
Innovation Solution
Development of modified AAV vectors with surface-bound saccharides for direct CNS administration, avoiding intracerebroventricular routes, to achieve widespread transduction from a single administration point, thereby overcoming immune detection and enhancing cell-specific and extensive tissue coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If AAV vectors are administered intravascularly to achieve non-invasive delivery, then widespread transduction is achieved in mice, but transduction is restricted in larger animals and requires extremely large doses with high off-target effects
Solution Approach 1:
The patent modifies the AAV capsid with specific serotypes (AAV2, AAV5, AAV8, AAV9) that have different tissue tropies, allowing targeted delivery to specific CNS regions while maintaining blood-brain barrier penetration. This local quality approach enables effective transduction in the CNS without requiring extremely large doses that cause off-target effects in peripheral organs.
Solution Approach 2:
The patent changes the capsid parameters of the AAV vector by selecting and modifying specific serotypes and their corresponding receptor interactions. This parameter change optimizes the balance between blood-brain barrier penetration and tissue-specific transduction, achieving reliable CNS delivery without the extreme doses required in larger animals.
2Area of stationary object
If multiple invasive injection sites are used to compensate for limited AAV spreading, then extensive tissue coverage is achieved, but the approach is not scalable for human treatment
Solution Approach 1:
The patent employs AAV serotypes with broad tropism and enhanced spreading capability that can transduce multiple CNS regions from a single injection site. This multi-functionality allows one injection to achieve extensive tissue coverage, making the approach scalable for human treatment where multiple invasive sites would be impractical.
Solution Approach 2:
The patent enhances the spreading dimension of AAV vectors by modifying capsid properties to facilitate diffusion through the CNS tissue from the injection site. This dimensional enhancement of spreading capability allows a single injection to cover extensive areas, eliminating the need for multiple injection sites.
3Reliability
If pre-existing immunity against AAV9 is present, then neutralizing antibodies clear viral particles from the system, but this precludes use in 43% of human adults
Solution Approach 1:
The patent segments the AAV delivery approach by offering multiple serotype options (AAV2, AAV5, AAV8, AAV9) rather than relying on a single serotype. This segmentation allows selection of a serotype that is not neutralized by pre-existing immunity in the patient, maintaining transduction efficiency while adapting to the individual's immune status.
Solution Approach 2:
The patent introduces dynamic adaptability in the vector selection process, where the choice of AAV serotype can be adjusted based on the patient's immune history and status. This dynamic approach ensures that a suitable serotype is selected for each patient, maintaining effectiveness across diverse human populations with varying immune backgrounds.
Data Source
AI summary
The present invention relates to modified adeno-associated virus (AAV) vectors for use in transducing a cell in the central nervous system (CNS) of a subject, and for use in the prevention or treatment of a CNS disease. In particular, the modified AAV vectors according to the present invention comprise at least one surface-bound saccharide, and are to be administered directly to the CNS but not intracerebroventricularly.