Hepatic siRNA delivery using recombinant human apolipoprotein A-I in mice

Apolipoprotein A-I (apo A-I), the major protein component of high density lipoprotein (HDL), plays a key role in reverse cholesterol transport from peripheral tissues to liver or steroidogenic organs. Class B, type 1 scavenger receptor (SR-BI) is abundantly expressed in these target tissues and recognizes apo A-I of HDL for selective cholesteryl ester uptake. Recently, we reported the liver-targeting potential of plasma-derived apo A-I and the efficient delivery of therapeutic small interfering RNAs (siRNA) assembled with cationic liposome and apo A-I. In this study, we expressed and purified recombinant human apo A-I (rhapo A-I), low endotoxin grade, from an Escherichia coli expression system. The liver-targeting property of rhapo A-I was compared to that of plasma-derived apo A-I. Using a hepatitis C virus mouse model, intravenous administration of virus-specific siRNA with liposome and rhapo A-I significantly inhibited viral protein expression, demonstrating great promise for its use in clinical applications.