Dual AAV Vector System for GDE Gene Segmentation

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Solution Overview

Problem

Current treatments for glycogen storage disease III (GSD III) are symptomatic and lack an effective long-term solution, with patients experiencing progressive myopathy, cardiomyopathy, and neurological manifestations due to glycogen accumulation, and existing therapies do not significantly alter the disease's long-term course or morbidity.

Innovation Solution

A dual recombinant AAV vector system comprising two AAV vectors, where one vector encodes the N-terminal part of the glycogen debranching enzyme (GDE) and the other encodes the C-terminal part, allowing for the production of a full-length GDE protein through overlapping nucleic acid sequences, is used to transduce liver, muscle, and CNS cells, promoting glycogen degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single AAV vector is used to deliver the full-length GDE gene, then the treatment approach is simple, but the AAV vector capacity is insufficient to accommodate the large GDE coding sequence

Engineering Contradiction:

Improvevector system complexityVSAvoidgene delivery capacity

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The GDE coding sequence is divided into two segments: the N-terminal portion (amino acids 1-263) is encoded by one AAV vector, and the C-terminal portion (amino acids 264-459) is encoded by another AAV vector. This segmentation allows each vector to stay within the packaging capacity limit while collectively delivering the complete functional gene through in vivo recombination.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If the GDE gene is split into two separate AAV vectors, then the gene delivery capacity is achieved, but the complexity of the vector system increases

Engineering Contradiction:

Improvegene delivery capacityVSAvoidvector system complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The two AAV vectors are designed with overlapping terminal repeat sequences that facilitate in vivo recombination. The vectors nest their genetic information in a way that allows cellular machinery to recombine them into a functional full-length GDE gene, effectively hiding the complexity of delivery within a simple dual-vector architecture.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Ease of operation

If symptomatic treatment approaches are used, then immediate symptom management is achieved, but long-term disease progression and morbidity are not altered

Engineering Contradiction:

Improvetreatment implementationVSAvoidlong-term disease outcome

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The AAV vectors serve as intermediaries that deliver the functional GDE gene directly to patient cells. This gene therapy approach addresses the underlying cause of the disease by restoring enzymatic function, rather than merely managing symptoms. The vectors mediate between the external treatment and the internal cellular processes, enabling long-term correction of the metabolic defect.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 dual AAV vector system effectively rescues muscle impairment, reduces glycogen accumulation, and restores muscle strength and glycemic levels in GSD III mouse models, demonstrating a viable strategy for treating the disease by expressing functional GDE protein and addressing the underlying glycogen accumulation.

Implementation Method 1

A dual recombinant AAV vector system comprising two AAV vectors... is used to transduce liver, muscle, and CNS cells

Methodology Applied

Scientific EffectViral transduction:

Implementation Method 2

the first and second nucleic acid sequences encoding said GDE comprise a polynucleotide region that permits the production of a full-length GDE protein

Methodology Applied

Scientific EffectHomologous recombination: