Synthesis of hyaluronic acid oligosaccharides with a GlcNAc-GlcA repeating pattern and their binding affinity with CD44

Org Biomol Chem. 2020 Jul 22;18(28):5370-5387. doi: 10.1039/d0ob01048k.

Abstract

Hyaluronic acid (HA) is a ubiquitous glycosaminoglycan in the extracellular matrix and a ligand of CD44, a transmembrane glycoprotein that is important in cell migration. Crystal and NMR studies found a hexasaccharide of the pattern (GlcA-GlcNAc)3 as the shortest HA that could bind to CD44, but molecular dynamics simulations indicated that a tetrasaccharide of the pattern (GlcNAc-GlcA)2 is the key structure interacting with CD44. Access to oligomers with such a repeat pattern is crucial in binding studies with CD44. Here we developed a synthetic procedure to afford the HA oligosaccharides with the GlcNAc-GlcA repeating unit and measured the binding interaction between these sugars and human CD44 by isothermal titration calorimetry (ITC). During the chemical synthesis, we successfully generated the β-glycosidic bond in the absence of neighbouring group participation and overcome the issues in the oxidation step. In addition, ammonia-free dissolving metal reduction for debenzylation and azido reduction has been applied in carbohydrate synthesis for the first time. ITC analysis revealed that the HA tetrasaccharide (GlcNAc-GlcA)2 could indeed interact and bind to the human CD44.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Carbohydrate Conformation
  • Humans
  • Hyaluronan Receptors / chemistry*
  • Hyaluronic Acid / chemical synthesis
  • Hyaluronic Acid / chemistry*
  • Oligosaccharides / chemical synthesis
  • Oligosaccharides / chemistry*
  • Oxidation-Reduction

Substances

  • CD44 protein, human
  • Hyaluronan Receptors
  • Oligosaccharides
  • Hyaluronic Acid