Nanoparticles help deliver anti-inflammatory drugs to 'rogue' immune cells

Researchers have developed a system which will help deliver anti-inflammatory drugs to immune cells that have gone out of control, while sparing their well-behaved counterparts.

The system uses nanoparticles made of tiny bits of protein designed to bind to unique receptors found only on neutrophils, a type of immune cell engaged in detrimental acute and chronic inflammatory responses.

Lead author Asrar B. Malik, the Schweppe Family Distinguished Professor and head of pharmacology in the UIC College of Medicine, said that the nanoparticle is very much like a Trojan horse, asserting that it binds to a receptor found only on these activated, sticky neutrophils, and the cell automatically engulfs whatever binds there. Because circulating neutrophils lack these receptors, the system is incredibly precise and targets only those immune cells that are actively contributing to inflammatory disease.

The researchers used intra-vital microscopy to follow nanoparticles in real-time in mice with induced vascular inflammation. The nanoparticles were labeled with a fluorescent dye, and could be seen binding to and entering neutrophils clustered together on the inner walls of capillaries, but not binding to freely circulating neutrophils.

If the researchers attached a drug called piceatannol, which interferes with cell-cell adhesion, to the nanoparticles, they observed that clusters of neutrophils that took up the particles detached from each other and from the blood vessel wall.

The cells were in effect neutralized and could no longer contribute to inflammation at the site of an injury.

The findings have been published online in journal Nature Nanotechnology.