Targeting of asialofetuin sugar chain-bearing liposomes to liver lysosomes

Specific direction of liposomes bearing an asialofetuin sugar chain (AFSC) to liver parenchymal cells was examined both in vivo and in vitro. The AFSC-bearing liposomes were preferentially recovered in the liver within several minutes after an intravenous injection into mice and were found to be predominantly localized in mitochondrial-lysosomal fraction. The massive distribution of the AFSC-liposomes in this fraction was also confirmed by using a lysosomal protease inhibitor, E-64-d. In isolated rat hepatocytes, the uptake of AFSC-liposomes was increased 2-3-fold as compared with the control liposomes without AFSC. Thus liposomes bearing AFSC would be useful to target enzymes to liver lysosomes.