Cyclodextrin conjugated ferritin nanocages reduce intracellular cholesterol level in foam cells

Accumulation of lipid-laden macrophages (foam cells) is characteristic of atherosclerosis development in the arterial walls. Ferritin nanocages have been found to passively accumulate in the atherosclerotic plaque. Ferritin has been actively investigated as a carrier for contrast agents in atherosclerosis diagnosis. We demonstrate the potential of ferritin as a carrier for therapeutic molecules to mediate cholesterol reduction from foam cells. Cyclodextrin molecules are chemically conjugated to the ferritin nanocages surface or encapsulated within the nanocages using metal co-loading methods. The cyclodextrin-conjugated ferritin has nanomolar affinity to cholesterol molecules. Treatment of foam cells with the conjugates shows decreased levels of intracellular accumulated cholesterol. The preferential localization of ferritin to foam cells is due to transferrin receptor-mediated endocytosis process. These findings show that ferritin nanocages as carriers localize cyclodextrin molecules to foam cells which mediate intracellular cholesterol reduction, thus highlighting its potential use as a therapeutic agent.