Airway macrophage specific glycocalyx expression and remodeling following viral infection.

The cell surface glycocalyx is a pericellular matrix that surrounds all cells, including macrophages, and regulates their function and interaction with the environment. The glycocalyx is composed of a range of glycans and glyco-proteins and its shedding into the blood is observed in, and is used as a marker of, a variety of inflammatory conditions such as viral infections. However, little is known about the signals and locations that regulate glycocalyx formation and heterogeneity across macrophage subsets. We now report that mouse lung macrophages express a glycocalyx that is dependent on their anatomical location and the mediators driving their differentiation from monocytes. Furthermore, during inflammatory conditions, caused by viral infection, the macrophage glycocalyx is remodelled in complex ways. Overall, our study provides a novel pathway involved in macrophage glycocalyx formation at rest and during inflammatory responses at mucosal tissue sties. This impacts our emerging understanding of the glycocalyx on immune cells beyond the classical paradigm of glycocalyx regulation of endothelial and vascular function.