Muscle-Tropic AAV Compositions for Uniform Microdystrophin Expression in DMD
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Solution Overview
Problem
Existing gene therapies for Duchenne Muscular Dystrophy (DMD) result in low and non-uniform expression of microdystrophin protein in skeletal muscles, necessitating improved treatment methods.
Innovation Solution
Development of adeno-associated viral (AAV) compositions containing a nucleic acid molecule with a muscle-specific promoter, codon-optimized microdystrophin sequence, and DRG de-targeting miRNA binding sites, encapsidated by an engineered capsid protein with reduced liver tropism and increased muscle tropism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing gene therapies are used for DMD treatment, then microdystrophin protein is expressed in skeletal muscles, but the expression level is low and non-uniform
Solution Approach 1:
The patent applies local quality by using muscle-specific promoters (such as muscle creatine kinase promoter) to drive microdystrophin expression specifically in skeletal muscle tissues. This ensures high-level, uniform expression precisely where needed in the target tissue, while avoiding expression in non-target organs like the liver, thereby resolving the contradiction between achieving uniform expression and treatment effectiveness
Solution Approach 2:
The patent employs parameter changes by optimizing the capsid protein structure through amino acid substitutions and additions to enhance muscle tropism and reduce liver tropism. These parameter modifications to the viral vector enable controlled, uniform high-level expression of microdystrophin in skeletal muscles, directly addressing the non-uniform expression problem of existing therapies
2Quantity of substance
If existing gene therapies are used for DMD treatment, then microdystrophin protein is expressed in skeletal muscles, but the expression level is low
Solution Approach 1:
The patent uses muscle-specific promoters to concentrate microdystrophin expression specifically in skeletal muscle tissues, achieving high local concentrations of the therapeutic protein where it is most needed. This localized high-level expression directly improves both the quantity of functional protein and the reliability of treatment outcomes
Solution Approach 2:
The patent utilizes engineered AAV capsids that are optimized copies of natural viral particles, with modified surface proteins that enhance binding affinity to muscle tissue receptors. These improved viral vectors efficiently deliver the microdystrophin gene, resulting in high-level protein expression and effective treatment
3Adaptability or versatility
If AAV compositions with engineered capsid protein are used, then muscle tropism is increased and liver tropism is reduced, but the capsid structure is more complex
Solution Approach 1:
The patent applies local quality by introducing specific amino acid substitutions and additions at targeted locations on the capsid protein structure. These localized modifications to hypervariable regions of the capsid enable selective enhancement of muscle tropism and reduction of liver tropism without requiring complete redesign of the entire capsid, thus achieving high tissue specificity with minimal structural complexity
Data Source
AI summary
The present invention provides novel gene therapy compositions for use in treatment of Duchenne Muscular Dystrophy (DMD).