Expression and characterization of myristoylated preS1-conjugated nanocages for targeted cell delivery

• Ferritin nanocages were fused to preS1 peptides from hepatitis B virus (HBV) (preS1–nanocages).
• Myristoylated preS1–nanocages were prepared in an Escherichia coli expression system.
• The preS1–nanocages formed stable, high-molecular-weight complexes.
• The preS1–nanocages were not cytotoxic and showed good affinity for HepaRG cells.

Lipid modification of proteins plays key roles in cellular signaling pathways. We describe the development of myristoylated preS1–nanocages (myr–preS1–nanocages) that specifically target human hepatocyte-like HepaRG cells in which a specific receptor-binding peptide (preS1) is joined to the surface of naturally occurring ferritin cages. Using a genetic engineering approach, the preS1 peptide was joined to the N-terminal regions of the ferritin cage via flexible linker moieties. Myristoylation of the preS1 peptide was achieved by co-expression with yeast N-myristoyltransferase-1 in the presence of myristic acid in Escherichia coli cells. The myristoylated preS1–nanocages exhibited significantly greater specificity for human hepatocyte-like HepaRG cells than the unmyristoylated preS1–nanocages. These results suggest that the lipid-modified nanocages have great potential for effective targeted delivery to specific cells.