Hyaluronic Acid Decoration Facilitates CD44‐Mediated Targeting and Alters Protein Corona Formation of Extracellular Vesicles

Cell recognition and uptake of extracellular vesicles (EVs) is mediated by a variety of surface molecules. Growing interest has recently been drawn towards glycan structures on EVs. Hyaluronic acid (HA) is a negatively charged glycosaminoglycan that can decorate the surface of EVs from different origins. HA is a ligand for adhesion receptor CD44, which is overexpressed in various cancers and inflammatory diseases. Although HA has been utilised as a surface decoration to improve CD44-mediated targeting of synthetic nanoparticles and EVs, the role of CD44 in the uptake of EVs is not well known. To assess the importance of CD44 in the interactions and endocytosis of HA-decorated EVs, uptake of HA-decorated and nondecorated EVs into CD44-expressing and -deficient cells was investigated using microscopic methods. The uptake of HA-decorated EVs was significantly increased into cells that expressed CD44, but no differences in endocytosis mechanisms were found. Additionally, the formation of plasma-derived protein corona in HA-decorated and nondecorated EVs was investigated using multi-parametric surface plasmon resonance and mass spectrometry. HA-decoration was found to cause a formation of thicker corona and enrichment of plasma-derived protein corona components. These findings highlight the role of HA in enhancing CD44-mediated EV targeting and modulating the composition of protein corona.