Nanotraps with biomimetic surface as decoys for chemokines

A creation of nanotraps that could selectively recognize the chemotactic mediators of leukocyte adhesion and eliminate them from the bloodstream and tissue intercellular matrix is a promising approach for the treatment of various inflammatory and autoimmune diseases. We designed nanotraps as artificial decoy receptors based on poly(lactic acid) (PLA) nanoparticles covered by heparin and bearing on the surface two fragments of CCR5 receptor (N-terminal domain, Nt, and second extracellular loop, ECL2), responsible for chemokine binding. In order to attach Nt and ECL2 to the heparin shell, the corresponding peptides were modified with N- and/or C-terminal oligolysines. The presence of the nanotraps in the cell medium completely eliminated the activating effect of a CCR5 ligand, chemokine Rantes, while strongly decreasing the adhesion of monocytes to the human endothelial cells. We found that the modified ECL2 alone was also able to prevent monocyte adhesion, thus acting as a decoy receptor itself.