Ligand Coupling to the AAV Capsid for Cell-Specific Gene Transfer

Area of Science:

• Molecular Biology
• Biotechnology
• Gene Therapy

Background:

• Adeno-associated virus (AAV) vectors are crucial for gene therapy, but their cellular entry relies on non-specific attachment receptors.
• Targeted delivery of AAV vectors to specific cell types is essential for maximizing therapeutic efficacy and minimizing off-target effects.

Purpose of the Study:

• To engineer AAV vectors for receptor-mediated cell entry and selective gene delivery.
• To compare different methods of attaching targeting ligands to the AAV capsid.

Main Methods:

• Rational engineering of AAV capsid by mutating contact residues.
• Covalent coupling of targeting ligands to the AAV capsid surface.
• Genetic coupling via fusion protein expression (VP2-ligand).
• Biochemical coupling using split-intein-mediated protein trans-splicing.

Main Results:

• Selective gene delivery to target-receptor positive cells was achieved.
• Two distinct coupling strategies were successfully implemented: genetic and biochemical.
• Genetic coupling is suitable for designed ankyrin repeat proteins.
• Biochemical coupling accommodates single-chain antibody fragments.

Conclusions:

• Engineered AAV capsids with high-affinity ligands enable precise targeting of specific cell populations.
• Both genetic and biochemical coupling methods offer versatile approaches for AAV vector functionalization.
• These advancements hold significant potential for improving the safety and effectiveness of gene therapies.