Modified ITR AAV Vector for High-Purity Gene Packaging
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Solution Overview
Problem
Conventional recombinant adeno-associated virus (rAAV) vectors suffer from issues such as low DNA molecule purity, low gene expression efficiency, and risks of insertional mutations due to impure rAAV vector DNA, which limits their clinical use in gene therapy applications.
Innovation Solution
The development of precision DNA recombinant adeno-associated virus (pciAAV) vectors that eliminate plasmid backbone impurity DNA through a modified ITR design, enhancing packaging efficiency and gene expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional rAAV packaging system using conventional ITRs is used, then the packaging process is simple and well-established, but the DNA molecule purity is low (containing 3-6% plasmid backbone impurity DNA) and gene expression efficiency is reduced
Solution Approach 1:
The patent extracts and removes the harmful plasmid backbone impurity DNA from the packaging system by using a modified ITR design that specifically prevents its incorporation into the viral genome. The modified ITR structure eliminates the binding sites for plasmid backbone sequences, thereby extracting the impurity from the final viral particle.
Solution Approach 2:
The patent changes the structural parameters of the ITR sequences by modifying their nucleotide composition and arrangement. This parameter change in the ITR structure alters its binding specificity to prevent plasmid backbone DNA from being packaged, thereby improving DNA molecule purity without significantly complicating the packaging system.
2Reliability
If traditional rAAV packaging system is used, then the packaging process is straightforward, but gene expression efficiency is low and clinical toxic side effects occur
Solution Approach 1:
The patent converts the potentially harmful plasmid backbone impurity DNA into a beneficial design feature by using the modified ITR structure to specifically exclude it from the viral genome. This exclusion prevents insertional mutations and clinical toxic side effects while maintaining high gene expression efficiency.
Solution Approach 2:
The patent creates a simplified copy of the traditional ITR structure with modified sequences that retain the essential packaging function while eliminating the harmful plasmid backbone binding capability. This copied and modified ITR structure achieves both high reliability gene expression and safety.
3Ease of manufacture
If conventional ITR packaging design is used, then the vector production is established and straightforward, but insertional mutations and severe medical incidents risk increases
Solution Approach 1:
The patent performs preliminary action by modifying the ITR structure before the packaging process to prevent plasmid backbone impurity DNA from being incorporated into the viral genome. This preliminary structural modification eliminates the risk of insertional mutations during subsequent packaging and clinical applications.
Solution Approach 2:
The patent extracts the harmful plasmid backbone sequences from the packaging system by designing modified ITRs that do not bind to these sequences. This extraction prevents the harmful factors from entering the viral particle while maintaining ease of manufacture through a straightforward packaging process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The pciAAV vectors improve gene packaging and expression efficiency, reducing clinical risks and promoting the safety and effectiveness of rAAV-based gene therapy.
Implementation Method 1
The two ends of the AAV DNA genome feature 145 bp inverted terminal repeats (ITRs), of which the terminal 125 bases form a longer palindromic structure capable of self-folding via complementary base pairing, presenting a T-shaped hairpin structure
Implementation Method 2
AAV viral particles infect cells, enter the nucleus, uncoat, and release the AAV genome into the nucleus
Implementation Method 3
the 3′ end serves as a primer for DNA synthesis to generate a second strand, forming a double-stranded DNA molecule that initiates the expression of genes carried by the AAV genome
Implementation Method 4
The positive strand and strand DNA molecules of the AAV genome can also complement each other to form double-stranded DNA molecules, enabling gene expression
Implementation Method 5
inter-molecular ITRs spontaneously combine to form dimers and multimers, which allow for the long-term or even lifelong expression of exogenous genes in cells
Data Source
AI summary
A precision recombinant adeno-associated virus (pciAAV) vector and the use thereof in gene therapy, gene editing, and gene regulation. The pciAAV vector is obtained by packaging an unpackaged pciAAV genome, said pciAAV genome containing the following, in sequence: (a) a modified ITR, which lacks a D element and a trs sequence; (b) a gene of interest or a protection sequence; (c) a complete ITR; (d) a gene of interest or a protection sequence; and (e) a modified ITR, which lacks a D element and a trs sequence; wherein at least one of the segments (b) and (d) contains a gene of interest. In the present invention, the level of impure DNA in the AAV vector is greatly reduced, gene expression efficiency is improved, random integration in the AAV gene vector is reduced, and the risk of gene mutation is reduced by the precision recombinant adeno-associated virus (pciAAV) vector.