Gene therapy using Aβ variants for amyloid reduction.

Area of Science:

• Neuroscience
• Biochemistry
• Genetics

Background:

• Toxic amyloid formation is a hallmark of neurodegenerative diseases like Alzheimer's.
• Existing peptide inhibitors face challenges with degradation and blood-brain barrier penetration.
• Developing effective delivery methods for brain-targeted therapeutics is crucial.

Purpose of the Study:

• To create and evaluate novel amyloid beta (Aβ) variants for inhibiting Aβ aggregation and toxicity.
• To establish a gene therapy approach using adeno-associated virus (AAV) for delivering these variants to the mouse brain.
• To assess the therapeutic potential of Aβ variants in a mouse model of Alzheimer's disease.

Main Methods:

• Engineered a minigene to express full-length Aβ variants (F20P, F19D/L34P) in the mouse brain.
• Utilized adeno-associated virus (AAV) for intraventricular injection and lifelong expression in APP/PS1 transgenic mice.
• Assessed Aβ levels, plaque burden, neuroinflammation, and in vitro aggregation/disassembly properties.

Main Results:

• Identified Aβ variants F20P and F19D/L34P that inhibit wild-type Aβ aggregation, promote fibril disassembly, and reduce oligomer toxicity.
• Lifelong expression of the F20P variant significantly reduced Aβ levels, plaque burden, and neuroinflammation in APP/PS1 mice.
• The F19D/L34P variant did not show significant therapeutic effects in the mouse model.

Conclusions:

• AAV-mediated delivery of engineered Aβ variants, specifically F20P, represents a potential novel therapeutic strategy for Alzheimer's disease.
• This approach offers a framework for developing targeted peptide inhibitors for other protein-misfolding diseases.
• Overcoming delivery challenges is key to translating amyloid inhibitor strategies into effective treatments.