Efficient Liver Targeting by Polyvalent Display of a Compact Ligand for the Asialoglycoprotein Receptor

J Am Chem Soc. 2017 Mar 8;139(9):3528-3536. doi: 10.1021/jacs.6b12964. Epub 2017 Feb 23.

Abstract

A compact and stable bicyclic bridged ketal was developed as a ligand for the asialoglycoprotein receptor (ASGPR). This compound showed excellent ligand efficiency, and the molecular details of binding were revealed by the first X-ray crystal structures of ligand-bound ASGPR. This analogue was used to make potent di- and trivalent binders of ASGPR. Extensive characterization of the function of these compounds showed rapid ASGPR-dependent cellular uptake in vitro and high levels of liver/plasma selectivity in vivo. Assessment of the biodistribution in rodents of a prototypical Alexa647-labeled trivalent conjugate showed selective hepatocyte targeting with no detectable distribution in nonparenchymal cells. This molecule also exhibited increased ASGPR-directed hepatocellular uptake and prolonged retention compared to a similar GalNAc derived trimer conjugate. Selective release in the liver of a passively permeable small-molecule cargo was achieved by retro-Diels-Alder cleavage of an oxanorbornadiene linkage, presumably upon encountering intracellular thiol. Therefore, the multicomponent construct described here represents a highly efficient delivery vehicle to hepatocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asialoglycoprotein Receptor / metabolism*
  • Bridged Bicyclo Compounds / chemistry*
  • Bridged Bicyclo Compounds / metabolism
  • Crystallography, X-Ray
  • Drug Carriers / chemistry
  • Hepatocytes / metabolism*
  • Humans
  • Ketones / chemistry*
  • Ketones / metabolism
  • Liver / cytology
  • Liver / metabolism*
  • Models, Molecular
  • Molecular Structure
  • Polymers / chemistry*
  • Polymers / metabolism

Substances

  • Asialoglycoprotein Receptor
  • Bridged Bicyclo Compounds
  • Drug Carriers
  • Ketones
  • Polymers