Liver-Specific Cas9 Codon Optimization for CRISPR Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Classic codon optimization methods are ineffective for achieving specific expression of Cas9 in human liver tissue due to variations in codon usage and tRNA frequencies across different cell and tissue types, leading to suboptimal expression of the Cas9 protein.
Innovation Solution
Development of recombinant nucleic acid molecules encoding Cas9 that are specifically codon-optimized for human liver expression, utilizing an adeno-associated virus (AAV) vector linked with a liver-specific promoter and optimized for increased expression, including modifications such as CpG dinucleotide removal to enhance safety and efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If classic codon optimization is applied to Cas9 sequences, then general expression levels improve, but tissue-specific expression efficiency deteriorates
Solution Approach 1:
The patent applies local quality by creating tissue-specific codon optimization tables that tailor codon preferences to individual liver cell types (hepatocytes, cholangiocytes, hepatic stellate cells, Kupffer cells, endothelial cells) rather than using a generic codon optimization approach. Each cell type has its own codon frequency profile derived from endogenous genes, allowing the Cas9 sequence to be optimized for specific tissue contexts.
Solution Approach 2:
The patent changes the parameters of codon optimization by moving from universal codon tables to tissue-specific codon tables. The codon optimization process is reparameterized to reflect the actual codon usage frequencies measured in liver tissue, transforming the optimization criteria to match the biological reality of the target tissue environment.
2Reliability
If Cas9 is delivered to liver tissue using traditional methods, then gene editing capability is achieved, but expression efficiency in target tissue deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-optimizing the Cas9 nucleic acid sequence with liver-specific codon tables before delivery. The sequence is prepared in advance with codons selected based on liver tissue codon frequencies, ensuring that once delivered to the target tissue, the sequence is immediately ready for high-efficiency translation without requiring post-delivery optimization.
3Adaptability or versatility
If generic codon optimization tables are used, then sequence compatibility is maintained, but translation efficiency in liver tissue deteriorates
Solution Approach 1:
The patent replaces generic, one-size-fits-all codon optimization with localized, tissue-specific codon optimization. By measuring actual codon frequencies in liver cell types and applying those specific profiles to Cas9 sequence optimization, the patent achieves both sequence compatibility (through systematic optimization) and enhanced translation efficiency (through tissue-matched codon preferences).
Data Source
AI summary
Described are recombinant nucleic acid molecules for increased expression of Cas9 in human liver. In some embodiments, the recombinant nucleic acid molecules are provided in compositions and methods for gene editing, specifically using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR).