CEP290 Minigene Therapy for Conventional AAV Size Limits
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Solution Overview
Problem
Current treatments for ciliopathies, such as Leber congenital amaurosis, are limited by the large size of cilia-associated genes like CEP290, which hinders successful gene therapy using conventional AAV vectors, and genome editing methods like CRISPR/Cas9 have off-target effects and are applicable to only one type of mutation.
Innovation Solution
Development of gene therapy vectors, such as rAAV vectors, containing minigenes encoding CEP290 protein fragments without the 'M region, along with inhibitory nucleic acids that target mutant CEP290, to restore cilial length and improve photoreceptor function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AAV vector-mediated gene delivery is used to deliver full-length CEP290 gene, then complete CEP290 protein function can be restored, but the large gene size (8 kb) exceeds the packaging capacity of conventional AAV vectors
Solution Approach 1:
The CEP290 gene is divided into multiple segments, with the critical functional domain (amino acids 580-1695, excluding the M region) being packaged into AAV vectors. This segmentation allows the essential therapeutic function to be delivered within the vector's size constraints while omitting non-essential regions.
Solution Approach 2:
The M region (amino acids 1695-1966) is extracted and removed from the CEP290 gene sequence packaged in the AAV vector. This extraction eliminates the problematic region that causes harmful effects while retaining the beneficial functions of the remaining CEP290 domains.
2Manufacturing precision
If genome editing methods like CRISPR/Cas9 are used to correct CEP290 mutations, then specific mutations can be corrected, but off-target effects occur and only one mutation type can be addressed
Solution Approach 1:
Instead of attempting to correct all possible CEP290 mutations through genome editing, the invention converts the limitation of addressing only specific mutations into a benefit by using a minigene approach that provides a functional CEP290 domain regardless of the specific mutation present in the patient's endogenous gene.
3Object-generated harmful factors
If inhibitory nucleic acids are used to target mutant CEP290, then expression of harmful mutant protein is reduced, but there is risk of silencing the therapeutic minigene expression
Solution Approach 1:
The inhibitory nucleic acids are designed with high specificity to target only mutant CEP290 sequences through carefully selected guide regions that match mutant-specific sequences. This local quality control ensures that wild-type and minigene-derived CEP290 sequences are not affected, allowing selective suppression of harmful mutant protein while preserving therapeutic protein expression.
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.