Synthetic Circular DNA Vectors Without Bacterial Signatures
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Solution Overview
Problem
Current gene therapy methods, such as traditional bacterial plasmid DNA vectors and recombinant adeno-associated viral (rAAV) vectors, face limitations including bacterial origins, immunogenicity, and limited packaging capacity, which can lead to adverse effects and reduced persistence of gene expression.
Innovation Solution
Development of non-viral isolated circular DNA vectors that lack bacterial origins and immunogenic signatures, utilizing a double D (DD) element for enhanced persistence and packaging capacity, allowing for the delivery of therapeutic genes for conditions like retinal dystrophies without the need for viral vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional bacterial plasmid DNA vectors are used for gene delivery, then the vectors can be easily manufactured and have high stability, but they contain bacterial genes and signatures that cause immunogenicity and adverse effects
Solution Approach 1:
The patent extracts and removes bacterial origin sequences, replication origins, and antibiotic resistance genes from the plasmid vector construction process. The circular DNA vector is designed to lack these bacterial elements entirely, eliminating immunogenicity while maintaining ease of in vitro manufacturing through cell-free synthesis methods.
2Duration of action of stationary object
If recombinant adeno-associated viral (rAAV) vectors are used to achieve long-term persistence, then gene expression persists long term, but the packaging capacity is limited to about 4.5 Kb and manufacturing is difficult
Solution Approach 1:
The patent creates a synthetic circular DNA vector that copies the persistent episomal behavior of rAAV vectors in the cell nucleus without requiring actual viral components. This artificial chromosome replicates the long-term persistence mechanism while eliminating viral manufacturing complexity and achieving larger packaging capacity.
3Productivity
If bacterial expression systems are used to produce plasmid DNA vectors, then the vectors can be produced efficiently, but contaminating impurities like endotoxins and bacterial genomic DNA are introduced
Solution Approach 1:
The patent replaces the biological bacterial expression system with an in vitro cell-free synthesis system. This mechanical/chemical approach produces circular DNA vectors without biological contaminants such as endotoxins and bacterial genomic DNA, while maintaining high production efficiency through optimized in vitro transcription and replication assays.
4Quantity of substance
If plasmid DNA vectors are used, then they can carry large payloads, but they contain CpG motifs that trigger immune responses
Solution Approach 1:
The patent modifies the sequence composition parameters of the circular DNA vector by eliminating CpG motifs and other bacterial signatures from the design. The vector sequence is carefully constructed to avoid immunogenic patterns while maintaining the ability to carry large therapeutic payloads, thus reducing immune responses.
Data Source
AI summary
Provided herein are isolated DNA vectors comprising a heterologous gene, wherein the DNA vector is devoid of bacterial plasmid DNA and/or bacterial signatures, which can abrogate persistence in vivo. The invention also features pharmaceutical compositions (non-immunogenic pharmaceutical compositions) including the DNA vectors of the invention, which can be used for induction of long-term, episomal expression of a heterologous gene in a subject. The invention involves methods of treating a subject by administering the DNA vectors of the invention, including methods of treating disorders associated with a defect in a target gene.