rAAV CAPN3 Gene Delivery With Skeletal Muscle-Specific Expression

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Solution Overview

Problem

There is no effective treatment for limb girdle muscular dystrophy type 2A (LGMD2A), a genetic disorder caused by mutations in the calpain3 gene, and previous attempts to deliver CAPN3 gene expression using adeno-associated virus (AAV) have resulted in cardiotoxicity.

Innovation Solution

Recombinant adeno-associated viruses (rAAVs) are developed to encode a protein with calpain3 (CAPN3) activity, using muscle-specific promoters like tMCK to ensure skeletal muscle expression without cardiac toxicity, and are administered via intramuscular or intravenous routes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CAPN3 gene expression is delivered using AAV with desmin promoter, then skeletal muscle expression is achieved, but cardiotoxicity occurs

Engineering Contradiction:

ImproveCAPN3 expression in skeletal muscleVSAvoidcardiotoxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the desmin promoter with a muscle-specific promoter (such as MCK promoter) that is selectively active in skeletal muscle cells but not in cardiac cells. This ensures that CAPN3 expression is localized to skeletal muscle tissue only, eliminating the harmful cardiac toxicity while maintaining therapeutic effect in the target tissue.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies the promoter element parameter of the AAV vector by changing from desmin promoter to muscle-specific promoter (MCK promoter). This parameter change alters the tissue specificity of gene expression, confining CAPN3 expression to skeletal muscle and preventing cardiac expression that causes toxicity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If CAPN3 gene is delivered to correct LGMD2A, then muscle function improves, but no safe delivery method exists without toxicity

Engineering Contradiction:

Improvemuscle function correctionVSAvoidtoxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a muscle-specific promoter (MCK promoter) that is selectively active in skeletal muscle cells, ensuring that CAPN3 expression is localized to the target tissue (skeletal muscle) while avoiding expression in other tissues including the heart. This localizes the therapeutic effect to muscle function correction while eliminating systemic toxicity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses an AAV vector as an intermediary delivery vehicle that carries the CAPN3 gene under the control of a muscle-specific promoter. The AAV vector serves as a safe intermediary that delivers the therapeutic gene to skeletal muscle cells without causing toxicity, leveraging the virus's ability to transduce muscle tissue while the promoter controls expression specificity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20260062681A1Recombinant adeno-associated virus products and methods for treating limb girdle muscular dystrophy 2a

Publication Date: 2026.03.05 RES INST AT NATIONWIDE CHILDRENS HOSPITAL

AI summary

Products and methods for treating limb girdle muscular dystrophy 2A are provided. In the methods, recombinant adeno-associated viruses deliver DNA encoding a protein with calpain 3 activity.