CEP290 Minigene Delivery for AAV Packaging Limits in LCA
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current treatments for ciliopathies, such as Leber congenital amaurosis, are limited by the large size of cilia-associated genes like CEP290 exceeding the packaging limit of conventional AAV vectors, and genome editing methods have off-target effects.
Innovation Solution
Development of minigene therapy vectors, including rAAV vectors, that deliver specific CEP290 fragments encoded by nucleic acids, which are formulated for subretinal delivery using AAV capsids, and optionally include inhibitory nucleic acids to target mutant gene variants, without silencing the minigene expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional AAV vectors are used for gene delivery, then the packaging capacity is limited to approximately 4700 bp, but the CEP290 gene size is approximately 8 kb, making it impossible to deliver the full gene
Solution Approach 1:
The CEP290 gene is divided into multiple fragments (e.g., exons 1-10, 11-20, 21-30, 31-40, 41-52) that can be independently packaged into separate AAV vectors. Each fragment is smaller than the 4700 bp packaging limit, allowing successful delivery. The fragments are designed to be expressed in a coordinated manner to reconstruct the full protein function.
Solution Approach 2:
Multiple gene fragments are organized in a nested structure where each AAV vector contains a specific exon segment nested within a complete vector backbone. The vectors are designed with overlapping or adjacent expression cassettes that collectively represent the full CEP290 gene, with each vector nesting its specific fragment within the AAV capsid structure.
2Manufacturing precision
If genome editing methods such as CRISPR/Cas9 are used, then targeted gene correction is achieved, but off-target effects occur that can cause unintended mutations
Solution Approach 1:
The patent extracts only the specific exon fragments containing the mutation from the full CEP290 gene, delivering them via AAV vectors without requiring genome editing machinery. This approach replaces the need for CRISPR/Cas9 system components (Cas9 protein, guide RNA) that cause off-target effects, achieving precise correction by direct fragment delivery instead of enzymatic editing.
3Adaptability or versatility
If antisense oligonucleotides are used to target mutant genes, then specific mutation types can be addressed, but the approach is limited to only one type of mutation in a cilia-associated gene
Solution Approach 1:
The AAV vector system is designed with universal applicability to deliver any CEP290 exon fragment regardless of the specific mutation type. The vector backbone and delivery mechanism remain the same, while only the inserted exon fragment needs to be changed to match the patient's specific mutation, making the therapy versatile across different mutation types while maintaining precise targeting of the intended exon.
Data Source
AI summary
Aspects of the disclosure relate to compositions and methods useful for treating ocular ciliopathies, for example Leber congenital amaurosis (LCA). In some embodiments, the disclosure provides isolated nucleic acids comprising a transgene encoding a CEP290 protein fragment, and methods of treating ocular ciliopathies using the same.