Context-Specific Function of the Engineered Peptide Domain of PHP.B.

Area of Science:

• Biochemistry
• Molecular Biology
• Gene Therapy

Background:

• Adeno-associated virus (AAV) vectors are crucial for gene therapy.
• Engineering AAV capsids improves tissue transport and cell targeting.
• Understanding insert-capsid interactions is key for AAV engineering.

Purpose of the Study:

• To investigate the structural basis of Ly6a binding by the engineered AAV9-PHP.B variant.
• To determine the context-dependency of engineered peptide inserts in AAV capsids.
• To explore the transferability of AAV capsid engineering strategies between serotypes.

Main Methods:

• Comparative structural analysis of AAV1-PHP.B and AAV9-PHP.B.
• Examination of peptide-ligand interactions within different AAV capsid contexts.
• Functional assessment of engineered AAV vectors for tissue penetration and cell targeting.

Main Results:

• The 7-amino-acid peptide insert in AAV9-PHP.B facilitates Ly6a binding and blood-brain barrier transport.
• This peptide insert alone did not confer Ly6a binding when transferred to AAV1.
• Ly6a binding requires both the PHP.B peptide and AAV9 HVR VIII residues; capsid context influences vector performance.

Conclusions:

• AAV capsid engineering requires careful consideration of insert-capsid interactions and context.
• Successful transfer of receptor-binding activity between AAV serotypes is complex.
• Capsid context significantly impacts AAV vector performance beyond simple receptor attachment.