SluCas9 Single AAV Vector for DM1 Genome Editing
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Solution Overview
Problem
Current CRISPR-Cas9 systems for treating Myotonic Dystrophy Type 1 (DM1) require two AAV vectors due to the large size of Streptococcus pyogenes Cas9, increasing manufacturing costs and administrative complexity, and are limited in design flexibility.
Innovation Solution
Employing a single AAV vector encoding the smaller Staphylococcus lugdunensis Cas9 (SluCas9) along with one or more guide RNAs, optionally with a DNA-PK inhibitor, to target and excise CTG repeats in the DMPK gene, allowing for reduced manufacturing costs and enhanced design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Streptococcus pyogenes Cas9 (spCas9) is used in AAV-based CRISPR/Cas systems, then the system can achieve effective genome editing, but the large size of spCas9 requires two AAV vectors, increasing manufacturing costs and administrative complexity
Solution Approach 1:
The patent extracts the essential Cas9 function from the large spCas9 enzyme and implements it using a smaller ortholog, SluCas9 from Staphylococcus lugdunensis. This extraction of the core functionality while reducing size allows the CRISPR system to be delivered in a single AAV vector rather than two, directly resolving the contradiction between editing effectiveness and system complexity
Solution Approach 2:
The patent employs SluCas9, a smaller and potentially more cost-effective Cas9 ortholog, replacing the larger spCas9. This substitution with a 'cheaper' (in terms of vector capacity and manufacturing) alternative achieves the same genome editing function while reducing the number of vectors needed from two to one
2Reliability
If Streptococcus pyogenes Cas9 (spCas9) is used in AAV-based CRISPR/Cas systems, then the system can achieve effective genome editing, but manufacturing costs increase due to requiring two AAV vectors
Solution Approach 1:
The patent extracts the essential Cas9 function from the large spCas9 enzyme and implements it using a smaller ortholog, SluCas9 from Staphylococcus lugdunensis. This extraction of the core functionality while reducing size allows the CRISPR system to be delivered in a single AAV vector rather than two, directly resolving the contradiction between editing effectiveness and system complexity
Solution Approach 2:
The patent merges the Cas9 enzyme and guide RNA delivery into a single AAV vector by using SluCas9, which is small enough to fit within the vector's capacity constraints. This consolidation of components that previously required separate vectors reduces manufacturing complexity and cost while maintaining editing effectiveness
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
This approach effectively reduces RNA foci and corrects mis-splicing in DM1 patient cells, improving treatment efficacy and simplifying the administration protocol while maintaining high editing efficiency.
Implementation Method 1
CRISPR-based genome editing can provide sequence-specific cleavage of genomic DNA using a Cas9 and a guide RNA
Implementation Method 2
To repair these breaks, cells typically use an error prone mechanism of non-homologous end joining (NHEJ) which can lead to disruption of function in the target gene through insertions or deletion of codons
Data Source
AI summary
Compositions and methods for treating Myotonic Dystrophy Type 1 (DM1) are encompassed.