HDR Gene Editing in HSPCs for Precise Haploinsufficient-Gene Knock-In
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Solution Overview
Problem
Current gene editing technologies for hematopoietic stem cells (HSPCs) face low efficiency and potential genotoxicity due to low cell cycle phases and non-physiological transgene expression, necessitating improved safety and efficiency for therapeutic applications.
Innovation Solution
A method involving targeted integration by homology-directed repair (HDR) in haploinsufficient genes, using a nuclease and guide RNA to introduce a double-strand break, followed by a donor template with homology arms for precise knock-in cassette integration, purging cells with undesired editing outcomes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gene editing by HDR is applied in HSPCs, then precise modification of endogenous genes is achieved, but editing efficiency is low
Solution Approach 1:
The patent changes the cellular parameter by inducing cells to exit quiescence and enter active cell cycle phases (S/G2) using growth factors and cytokines, thereby increasing the proportion of cells permissive to HDR and improving editing efficiency while maintaining precision
Solution Approach 2:
The patent performs preliminary actions by pre-treating HSPCs with growth factors and cytokines before gene editing to activate cell cycle progression, ensuring cells are in the optimal state for efficient HDR when the editing agent is introduced
2Productivity
If viral vectors with strong promoters are used for gene therapy, then therapeutic efficacy is improved, but risk of insertional mutagenesis increases
Solution Approach 1:
The patent extracts and removes the harmful element (strong viral promoters) from the gene therapy construct, replacing them with endogenous promoters that drive expression only at the target locus, thereby eliminating insertional mutagenesis risk while maintaining therapeutic efficacy
Solution Approach 2:
The patent introduces an intermediary mechanism (HDR-based precise integration) that allows therapeutic genes to be inserted at specific safe harbor loci rather than randomly, mediating between the need for strong expression and the need to avoid mutagenesis
3Productivity
If selection strategies are used to enrich HDR-edited cells, then efficacy is improved, but genotoxic events may still persist
Solution Approach 1:
The patent converts the potentially harmful effect of selective pressure into a benefit by using it to purge out cells with genotoxic editing outcomes (indels, large deletions, translocations) while enriching for cells with correct HDR outcomes, thereby improving both efficacy and safety
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
Enhances the efficiency and safety of gene editing in HSPCs by enriching cells with uniform editing outcomes and preserving genome integrity, ensuring long-term survival and engraftment.
Implementation Method 1
targeted integration by homology-directed repair (HDR) in haploinsufficient genes, using a nuclease and guide RNA to introduce a double-strand break, followed by a donor template with homology arms for precise knock-in cassette integration
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2C
AI summary
The invention is directed to means and methods for efficient and safe genetic manipulation of a target cell, wherein a knock-out/knock in strategy is performed via HDR in a target gene that is haploinsufficient (and/or in single copy) in the cell.