A novel biomimetic probe for galectin‐3 recognition: Chemical synthesis and structural characterization of a β‐galactose branched sodium hyaluronate

Abstract

Sodium hyaluronate (HA), a derivative of hyaluronan, is a natural and biocompatible polysaccharide that interacts with cluster of differentiation‐44 receptor to promote fine‐tuning of inflammation, fibrosis, and tissue remodeling. HA has a smaller molecular weight than hyaluronan and is overall more stable being less prone to oxidation. In this study, we report a novel lactose‐functionalized sodium hyaluronate, named HYLACH®. Functionalization with multiple β‐galactose residues facilitates its interaction with galectin‐3, a β‐galactose binding lectin implicated in various pathological processes including inflammation, host defense, and fibrosis, especially critical in idiopathic pulmonary fibrosis (IPF). Our strategy was to modify HA, to varying extents, at carboxyl sites with 1‐amino‐1‐deoxy‐lactitol, in the presence of 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methyl morpholinium chloride in aqueous media. We characterized the chemical structure, molecular weight, and degree of substitution of HYLACH® using NMR spectroscopy and size exclusion chromatography. We further determined several key parameters including its stability toward enzymatic degradation and the binding affinity and conformational changes of galectin‐3 interaction with HYLACH®. Collectively, the generation of a novel functionalized HA with an ability to bind and suppress galectin‐3 function, in combination with safety and biocompatibility, offers the opportunity to test this compound in therapeutic trials of devastating fibrotic diseases such as IPF.