Journal: Cell reports
Article Title: AAVs targeting human carbonic anhydrase IV enhance gene delivery to the brain
doi: 10.1016/j.celrep.2025.116419
Figure Lengend Snippet: (A) Structure of CA-IV from human (PDB: 1ZNC ), macaque (modeled by AlphaFold 3 ), marmoset (modeled by AlphaFold 3), and mouse (PDB: 2ZNC ). Human CA-IV is shown in white. Regions that differ from human CA-IV in other species, and which may influence receptor binding by AAV variants, are highlighted in blue (mouse), green (marmoset), and magenta (macaque). (B) Illustration of critical stages of systemic AAV penetration into the brain from the bloodstream: (1) AAV binding to brain endothelial cell surface receptors; (2) cellular uptake of bound AAV through receptor-mediated internalization; and (3) transcytosis to enter the brain parenchyma. (C) Structure of the AAV9 capsid (PDB: 7MT0 41 ), highlighting the 3-fold spike and key variable regions (VR) VR-IV (green, residues 445–465), VR-V (blue, residues 488–511), and VR-VIII (purple, residues 578–596). The enlarged panel shows the interaction of VR-IV and VR-VIII from the same AAV capsid monomer (colored yellow) with VR-V from a different monomer (colored light gray). To construct our library of AAV capsid variants, a seven-residue randomized peptide was inserted between positions 588 and 589 of VR-VIII, and positions 587 and 588 were modified to either AQ or DG. (D) Pull-down-based selection workflow used to identify AAV variants that bind target receptors. Capsid variants that bind to the receptor (e.g., CA-IV or LY6A) are isolated with receptor-bound beads, followed by DNA extraction and NGS to identify the enriched variants. (E and F) Validation of pull-down-based selection for AAV variants binding mouse LY6A (E) and CA-IV (F) receptors. AAVs known to bind LY6A (PHP.B and PHP. eB) and mouse CA-IV (9P31 and 9P36) show significantly higher Er and Eh than other AAVs in a pool of ∼18,000 unique variants. Identically colored dots represent codon replicates of an AAV variant.
Article Snippet: Sequences encoding AAV capsid variants were cloned into the pUCmini-iCAP plasmid (Addgene ID: 103005).
Techniques: Binding Assay, Construct, Residue, Modification, Selection, Isolation, DNA Extraction, Biomarker Discovery, Variant Assay