Cas13 AAV Multiplex Gene Silencing for Hypercholesterolemia
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Solution Overview
Problem
A significant portion of patients with hypercholesterolemia and dyslipidemias are resistant to statin therapy or develop intolerance, leading to elevated cardiovascular disease risk and high therapeutic costs.
Innovation Solution
Development of recombinant adeno-associated virus (rAAV) vectors containing a transgene encoding a CB6 promoter-linked RNA-guided nuclease (RGN) and a multi-guide-RNA (multi-gRNA) expression cassette targeting genes associated with hypercholesterolemia or dyslipidemia, such as PCSK9, ANGPTL3, and APOB, for gene silencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If statin therapy is used to treat hypercholesterolemia, then cholesterol levels are reduced, but treatment resistance or intolerance develops in a significant portion of patients
Solution Approach 1:
The patent introduces AAV vectors as an intermediary delivery system to administer Cas13d RNA-guided nuclease and guide RNAs directly to hepatocytes. This bypasses the traditional statin pathway that encounters resistance, providing a novel mechanism for cholesterol reduction through direct gene silencing of PCSK9, ANGPTL3, and APOB genes in the liver.
Solution Approach 2:
The patent changes the therapeutic parameter from small molecule inhibition (statins) to RNA-guided gene silencing (Cas13d system). By altering the molecular mechanism from enzyme inhibition to mRNA degradation, the treatment overcomes resistance while maintaining effectiveness in reducing cholesterol-associated genes expression.
2Reliability
If multiple guide RNAs are included in a single AAV vector to target multiple genes, then gene silencing efficiency is improved, but vector complexity increases
Solution Approach 1:
The patent merges multiple guide RNA expression cassettes into a single AAV vector construct, allowing simultaneous delivery of multiple gRNAs (targeting PCSK9, ANGPTL3, and APOB) along with the Cas13d nuclease in one viral particle. This consolidation improves delivery efficiency and enables multiplexed gene silencing without requiring separate vectors for each target.
Solution Approach 2:
The AAV vector is designed with universal functionality to deliver both the Cas13d nuclease and multiple guide RNAs for different target genes. The single vector system can be customized to target various cholesterol-associated genes, providing a versatile platform that adapts to different therapeutic needs while maintaining a consistent delivery mechanism.
3Productivity
If AAV vectors are used for gene delivery, then delivery efficiency to hepatocytes is improved, but immune response and safety concerns arise
Solution Approach 1:
The patent employs a transient expression strategy where the AAV vector delivers Cas13d and guide RNAs that function temporarily in the hepatocytes. The RNA-guided nuclease system degrades target mRNAs without integrating into the host genome, and the AAV vector itself does not require permanent retention, allowing the system to achieve therapeutic effect while minimizing long-term immune exposure and safety risks.
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 rAAV vectors effectively silence target genes in hepatocytes, reducing total cholesterol levels and body mass in subjects, providing a therapeutic alternative for statin-resistant or intolerant patients.
Implementation Method 1
a transgene encoding a first nucleic acid sequence comprising a CB6 promoter operably linked to a RNA-guided nuclease (RGN) and second nucleic acid sequence encoding a multi guide-RNA (multi-gRNA) expression cassette comprising one or more sequences targeting a gene associated with hypercholesterolemia or dyslipidemia
Data Source
AI summary
Aspects of the disclosure relate to compositions and methods for multiplexed gene silencing in a cell or subject. In some embodiments, the disclosure provides an isolated nucleic acid or an rAAV encoding a transgene comprising a RNA-guided nuclease (RGN) operably linked to a first promoter, and a second promoter operably linked to a multi guide-RNA (multi-gRNA) expression cassette encoding one or more gRNAs targeting a gene associated with hypercholesterolemia or dyslipidemia. In some embodiments, the disclosure provides methods of treating a subject having hypercholesterolemia or dyslipidemia by administering the compositions.