Coordinating Adhesion with Repulsion: How Cells Leverage Hyaluronan Glycocalyx*

Cell rearrangements during proliferation, migration, synaptogenesis, and other dynamic physiological processes are often accompanied by alteration in hyaluronan synthesis and the associated hyaluronan-rich glycocalyx. Previously, we have shown that this bulky glycocalyx significantly weakens cell adhesion and tunes cell migration speed in a predictable, adhesion-dependent fashion. Building on these results, I will present new and consistent data quantifying the impact of hyaluronan expression in neural crest cell migration in vivo and ex vivo. I will then show how we use a biomimetic dynamic hyaluronan glycocalyx assay (made with templated hyaluronan synthase) to interrogate the role of glycocalyx in mechanobiology. We quantified the kinetics of cell adhesion versus the glycocalyx thickness and found that the HA glycocalyx modulates cell adhesion in a thickness-dependent manner, slowing but not altering the final number of adherent cells. Fluorescent labeling confirms localized removal of HA to promote focal adhesion formation by hyaluronidase. We also investigated the impact of the force generated by dynamic glycocalyx growth and found that cells become dramatically deformed, the number of focal adhesions is reduced, and thirty percent of adhered cells detach from the substrate. These results support the hypothesis that hyaluronan synthase can extrude polymers and drive glycocalyx assembly to generate forces large enough to influence cell mechanobiology, including focal adhesion turnover, size, and cell morphology.