Abstract
The transferrin receptor (TfR) mediates transcytosis across the blood-brain barrier (BBB), which offers a promising approach for the non-invasive delivery of therapeutics into the brain parenchyma. Employing the recombinant homodimeric murine TfR ectodomain, prepared in a biochemically functional state, we have selected a cognate Anticalin via phage display and bacterial cell surface display from a random library based on the human lipocalin 2 (Lcn2). After affinity maturation, several engineered lipocalin variants were identified that bind murine TfR in a non-competitive manner with the natural ligand (transferrin ⋅ Fe3+), among those an Anticalin – dubbed FerryCalin – exhibiting a dissociation constant (KD) of 3.8 nM. Epitope analysis using the SPOT technique revealed a sequential epitope in a surface region of TfR remote from the transferrin-binding site. Due to the fast kon rate and short complex half-life, as evidenced by real-time surface plasmon resonance (SPR) measurements, FerryCalin, or one of its related mutants, shows characteristics as a potential vehicle for the brain delivery of biopharmaceuticals.
Original language | English |
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Article number | e202200795 |
Journal | ChemBioChem |
Volume | 24 |
Issue number | 10 |
DOIs | |
State | Published - 16 May 2023 |
Keywords
- TfR
- blood brain barrier
- drug delivery
- lipocalin
- protein engineering