CRISPR-Cas Compositions for Precise Nonviral Transgene Insertion
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Solution Overview
Problem
Current gene therapy methods using viral vectors for CRISPR-based editing in immune cells face challenges such as unintended genomic integration, gene overexpression, and immune responses, limiting their clinical utility.
Innovation Solution
A composition comprising a targetable nuclease, a DNA-binding protein, and a donor template with homology directed repair (HDR) template, enhanced by an anionic polymer, stabilizes the CRISPR-Cas system for efficient nucleic acid modification, reducing reliance on viral vectors and minimizing off-target effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If viral vectors are used for CRISPR-based editing in immune cells, then gene integration can be achieved, but unintended genomic integration and gene overexpression occur
Solution Approach 1:
The patent segments the gene editing system into distinct functional components: a CRISPR-Cas nuclease system for targeted DNA cleavage, a separate donor template for providing repair sequences, and a delivery mechanism (electroporation) for introducing these components. This segmentation allows precise control over where editing occurs and what is integrated, eliminating the random integration inherent in viral vectors.
Solution Approach 2:
The patent uses electroporation as an intermediary delivery method between the external editing components and the target immune cells. This physical intermediary method replaces viral vectors, enabling controlled introduction of editing reagents without the harmful properties of viral integration, thereby achieving precise genome modification without random insertion.
2Productivity
If viral vectors are used for gene therapy, then transgene insertion is achieved, but immune responses and genotoxicity increase
Solution Approach 1:
The patent extracts and removes the viral vector component from the gene therapy system, replacing it with non-viral delivery methods (electroporation). This extraction eliminates the source of harmful immune responses and genotoxicity while maintaining the ability to deliver CRISPR editing components and achieve transgene insertion through controlled mechanisms.
Solution Approach 2:
The patent employs transient, non-integrating delivery methods (electroporation) that do not require persistent viral vectors. The editing components are introduced temporarily, perform their function, and are degraded, avoiding the long-term immune surveillance and response issues associated with viral vectors that persist in the host.
3Adaptability or versatility
If viral vectors are used for CRISPR editing, then editing can be performed, but off-target effects and genotoxicity occur
Solution Approach 1:
The patent applies local quality by providing a donor template with specific homology arms designed to match only the intended target locus in the genome. This localized homology ensures that the repair template is inserted only at the correct position, preventing off-target effects and enhancing editing safety while maintaining the versatility of the CRISPR system for different gene targets.
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 composition improves editing efficiency and cell viability, enabling precise and high-efficiency large transgene insertion in primary human cells and hematopoietic stem cells, while reducing potential genotoxicity and immune responses.
Implementation Method 1
The CRISPR-Cas system is a ribonucleoprotein complex that requires stabilization to prevent aggregation. The anionic polymer interacts with the positively charged protein components through electrostatic attraction, forming a stable complex that maintains nuclease activity.
Implementation Method 2
The targetable nuclease, such as Cas9, catalyzes the hydrolysis of phosphodiester bonds in the target DNA at the cleavage site, breaking the nucleic acid into fragments for subsequent repair.
Implementation Method 3
The donor template with homology arms undergoes homology directed repair through recombination with the cleaved target nucleic acid, inserting the desired genetic material at the precise location.
Implementation Method 4
The DNA-binding protein recognizes and binds to specific DNA sequences through base recognition and hydrogen bonding between the protein and nucleotide bases, positioning the template for repair.
Data Source
AI summary
The disclosure provides compositions and methods for modifying a target nucleic acid. In some embodiments, a composition can include a targetable nuclease, a DNA-binding protein, and a donor template comprising a homology directed repair (HDR) template and one or more DNA-binding protein target sequences. In some embodiments, a composition can include a Cas protein, one or more single guide RNAs (sgRNAs), and an anionic polymer.