Abstract 169: A Non-Viral Functionalized Nanoparticle Based Hepatocyte-Targeting Cholesteryl Ester Hydrolase Gene Delivery Strategy for Potential Alleviation of Atherosclerosis

Abstract

Current atherosclerosis treatment strategies primarily focus on limiting further cholesteryl ester (CE) accumulation within the plaques by reducing plasma LDL-cholesterol levels (the primary source of plaque CE) using multiple strategies. No therapy is currently available to enhance the removal of CE, a crucial step to reduce the burden of existing disease. Increasing hepatic CE hydrolysis by adenovirus or transgene mediated over-expression of CE hydrolase (CEH) enhances final elimination of cholesterol from the body and is anti-atherosclerotic. In an effort to advance towards application of this anti-atherosclerotic strategy, in the present study we developed a non-viral hepatocyte-specific platform, namely, galactose-functionalized polyamidoamine (PAMAM) dendrimer G5.0 (Gal-G5) for delivery of CEH expression vector via the hepatocyte-specific asialoglycoprotein receptor (ASGPR). ASGPR is triggered by binding of galactose residues and facilitates receptor-mediated endocytosis of large molecules across the hepatocyte plasma membrane. The data presented herein show increased specific uptake of Gal-G5 by hepatocytes in vitro (See Figure, Panel A) and liver in vivo (Panel B). Gal-G5 mediated delivery of CEH expression vector upregulated CEH expression in hepatocytes (Panel C), led to increased intracellular hydrolysis of HDL-CE and subsequent conversion/secretion of released FC into bile acids (Panel D). Gal-G5 mediated increased CEH expression in the liver significantly increased the flux of FC from HDL-CE into bile (Panel E) as well as feces (Panel F). These data are consistent with adenovirus or transgene-mediated over-expression of CEH and are likely to be anti-atherogenic. In conclusion, the development of this relatively non-toxic and efficient liver-specific gene delivery platform is an encouraging step towards clinical translation of strategies to enhance hepatic processes involved in final elimination of cholesterol from the body.