Ontogeny of Mechanosensation During Vascular Development

Abstract

Endothelial cells have the capacity to sense hemodynamic forces through the process of mechanotransduction. When blood flow starts in the embryo, many of the components required for sensing hemodynamic forces in the adult have not yet formed. We recently showed that hemodynamic forces were required for normal vascular development. In this work, we have been focusing on the development of a mechano‐sensory complex by studying the development of the glycocalyx. The glycocalyx forms extensions into the vascular lumen that are anchored directly to actin stress fibres of the cytoskeleton and transmit hemodynamic signals. By electron microscopy and immunohistochemical staining, we show that the glycocalyx is present as soon as blood flow starts. We then used selective enzymatic degradation to look at whether the glycocalyx has a functional role during vascular development. We found that during development, hyaluronan, but not other glycocalyx components, affected vascular permeability. We also found that degradation of heparan sulfate resulted in decreased expression of a subset of mechanotransduced genes.