BME PhD Proposal Seminar: Graham Marsh

The Role of Endothelial Luminal Layer in Leukocyte Capture

Supervised by Professor Richard Waugh

Abstract

The endothelial surface consists of a soft luminal layer containing endothelial microvilli and a protective sugar coating called the glycocalyx. The location of integrins and chemokine receptors relative to the microvilli of leukocytes is known, but the relative location of the chemokines and adhesion molecules on the endothelial microvilli in the endothelial glycocalyx remains to be determined. We have developed a novel approach to characterize both the mechanical stiffness and adhesiveness of the endothelial surface. A modified AFM cantilever with a 2.4 um bead attached to its tip is used to impinge the luminal surface. The force versus distance curves which are obtained from these measurements are fitted with a two-layer elastic model to determine the thickness and stiffness of the luminal layer. A bead functionalized with an antibody to ICAM-1 or IL8 and attached to a cantilever can be used to measure adhesion as a function of indentation force. By measuring the physical properties in endothelial cells and bond formation kinetics before and after stimulation with TNF , we will test the hypothesis that the endothelial cell modifies its mechanical and adhesive characteristics upon activation and thus plays an active role in leukocyte capture.