Engineered AAV Capsid Proteins for Selective Cardiomyocyte Transduction
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Solution Overview
Problem
Current AAV-based gene therapy vectors face challenges in efficiently and selectively transducing heart tissue, particularly cardiomyocytes, with significant off-target distribution leading to unwanted side effects and immune activation, and existing lentiviral vectors have integration and production complexities.
Innovation Solution
Development of modified AAV capsid proteins, such as AAV BI-15.1 and AAV BI-15.2, which exhibit specific tropism for murine endothelial cells, allowing selective transduction of primate heart tissue with reduced off-target expression and improved manufacturing ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AAV1 vector is used to deliver SERCA2a to cardiomyocytes, then cardiac-specific transduction is achieved, but transduction efficacy is extremely low (less than 1% of cardiomyocytes contain virus vector genomes)
Solution Approach 1:
The patent changes the capsid protein parameters of the AAV vector to create engineered variants (e.g., AAV2, AAV6, AAV8, AAV9, and hybrid capsids) with modified binding affinities and tissue tropisms. These parameter changes enable the vector to efficiently transduce cardiomyocytes while maintaining cardiac-specific targeting, resolving the low transduction efficacy problem of wild-type AAV1.
Solution Approach 2:
The patent employs composite capsid structures by combining different AAV serotype capsid proteins (e.g., chimeric capsids like AAV2/6, AAV2/8, AAV2/9 hybrids) to create vectors with enhanced cardiomyocyte transduction capability. This composite approach leverages the strengths of different serotypes to achieve both high transduction efficiency and cardiac specificity.
2Productivity
If AAV9 vector is used to transduce cardiomyocytes, then high transduction efficiency is achieved, but off-target distribution to liver and other tissues occurs leading to unwanted side effects
Solution Approach 1:
The patent modifies the capsid proteins to create vectors with enhanced local specificity for the heart. Engineered capsids (e.g., AAV-BI-15.1, AAV-BI-15.2) exhibit preferential binding to cardiac tissue receptors, concentrating the vector's action locally in the heart while minimizing off-target effects in liver, lung, and other tissues. This local quality enhancement reduces harmful off-target expression and immune activation.
Solution Approach 2:
The patent alters capsid protein parameters through mutagenesis and directed evolution to create variants with refined tissue tropism. These parameter changes enable the vector to maintain high cardiomyocyte transduction efficiency while reducing affinity for off-target tissues, thereby minimizing side effects and immune responses.
3Reliability
If lentiviral vectors are used for gene delivery, then integration into host genome is achieved, but production complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the integration function from the viral vector system and replaces it with non-integrating AAV vectors that rely on chromosomal integration of the transgene cassette through homologous recombination or non-homologous end joining. This extraction of the integration mechanism simplifies production by eliminating the need for complex lentiviral packaging systems while maintaining reliable gene delivery and expression.
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
These vectors achieve high cardiomyocyte transduction with minimal expression in off-target tissues, enabling effective gene therapy for heart diseases with reduced immune response and increased therapeutic efficacy.
Implementation Method 1
The viral capsid protein was found to specifically bind to primate heart tissue cells, and in particular primate heart muscle cells
Data Source
AI summary
This invention generally relates to the field of somatic gene therapy by using viral vectors, and in particular adeno-associated virus (AAV) vectors for the treatment of inherited or acquired diseases. More specifically, the invention relates to a viral capsid protein that provide for a specific transduction of murine endothelial cells for treating or preventing a heart disease in a primate. The viral capsid protein was found to specifically bind to primate heart tissue cells, and in particular primate heart muscle cells, and can be used to provide for an efficient and selective transduction of primate cardiomyocytes and ensure heart tissue-specific expression of one or more transgenes in the primate. The invention further relates to a recombinant viral vector, preferably an AAV vector, which comprises a capsid with at least one transgene packaged in the capsid. The viral vector is suitable for the therapeutic treatment of a cardiac disorder or disease in a primate. The invention further relates to cells and pharmaceutical compositions which comprise the viral vector according to the invention.