Probing Structural Selectivity of Synthetic Heparin Binding to Stabilin Protein Receptors

Authors

Elizabeth H. Pempe, University of North Carolina, Chapel HillFollow
Yongmei Xu, University of North Carolina, Chapel HillFollow
Sandhya Gopalakrishnan, University of Nebraska–LincolnFollow
Jian Liu, University of North Carolina, Chapel HillFollow
Edward N. Harris, University of Nebraska - LincolnFollow

Document Type

Article

Date of this Version

6-15-2012

Citation

The Journal of Biological Chemistry, 287 (June 15, 2012), pp. 20774-20783; doi: 10.1074/jbc.M111.320069

Comments

Copyright © 2012 by The American Society for Biochemistry and Molecular Biology, Inc. Used by permission.

Abstract

As one of the most widely used drugs worldwide, heparin is an essential anticoagulant required for surgery, dialysis, treatment of thrombosis, cancer, and general circulatory management. Stabilin- 2 is a scavenger clearance receptor with high expression in the sinusoidal endothelium of liver. It is believed that Stabilin- 2 is the primary receptor for the clearance of unfractionated and low molecular weight heparins in the liver. Here, we identify the modifications and length of the heparin polymer that are required for binding and endocytosis by both human Stabilin receptors: Stabilin-2 and its homolog Stabilin-1 (also found in liver endothelium). Using enzymatically synthesized ³⁵S-labeled heparan sulfate oligomers, we identified that sulfation of the 3-OH position of N-sulfated glucosamine (GlcNS) is the most beneficial modification for binding and endocytosis via both Stabilin receptors. In addition, our data suggest that a decasaccharide is the minimal size for binding to the Stabilin receptors. These findings define the physical parameters of the heparin structure required for efficient clearance from blood circulation. These results will also aid in the design of synthetic heparins with desired clearance rates.