Nano-sponge-like liposomes remove cholesterol crystals for antiatherosclerosis

Abstract

Atherosclerotic cardiovascular diseases remain the leading causes of morbidity and mortality worldwide. Cholesterol crystals in atherosclerotic plaques play an essential role in atherosclerosis progression. However, no clinical drugs have been used for removing cholesterol crystals from plaque to counter atherosclerosis. Previous studies identified the hydrophobic domain of lipid bilayer in liposomes acted as sinks for solubilizing hydrophobic cholesterol. Moreover, adjusting the composition of the lipid bilayer in liposomes can enhance its hydrophobic molecule loading capacity. Therefore, in this study, ginsenosides Rb1 (Rb1), one of main active components of ginseng which has a similar structure to cholesterol, is anchored into soy phospholipids bilayer with its hydrophobic region to prepare nano-sponge-like liposomes (Rb1-LPs), aiming to amplify the solubilization of cholesterol in lipid bilayer. For targeting delivery to atherosclerotic plaques, Annexin V (AnxV), a protein that can specifically recognize phosphatidylserine upregulated in atherosclerotic plaques, is applied to decorate the surface of Rb1-LPs by click reaction to obtain the final preparation of AnxV-Rb1-LPs. The in vitro studies showed that incorporating Rb1 into lipid bilayer remarkably increased the affinity of the lipid bilayer to free cholesterol and the solubilization of cholesterol crystals. Additionally, nano-sponge-like liposomes could efficiently reduce the accumulation of cholesterol crystals and improve cholesterol efflux, finally inhibiting inflammation and apoptosis in cholesterol-laden cells. Furthermore, AnxV-Rb1-LPs could efficiently accumulate in atherosclerotic plaques after intravenous injection, exert nano-sponge-like functions to remove intra- and extracellular cholesterol crystals, ultimately alleviating inflammation and apoptosis in atherosclerotic plaques for antiatherosclerosis. Therefore, AnxV-Rb1-LPs provide a potential strategy for removing cholesterol crystals in atherosclerotic plaques and can be further utilized in other diseases with excessive cholesterol accumulation.

Keywords: Atherosclerosis; Cholesterol crystals; Ginsenoside Rb1; Liposomes; Nano-sponge.