Physics Colloquium

Prof. Gerald Fuller, Stanford

"All Stressed Out: Mammalian Cells Subject to Adhesive and Hydrodynamic Stress"

4:00pm, The John A. Wheeler Lecture Hall (RLM 4.102). Coffee and cookies will be served at 3:45pm in RLM 4.102

Abstract: Mammalian cells are frequently subjected to mechanical stress. Here, I examine mechanotransduction of endothelial cells in flowing environments and the adhesion of bacteria to bladder cells.

Vascular endothelial cells line the interior walls of our blood vessels and are sensitive to surface shear stresses. These stresses are known to affect the shape and orientation of endothelial cells. We find that stagnation point flows and constriction flows create regions of well-controlled spatial variations of wall shear stresses. Live-cell imaging reveals migration dynamics, in response to stresses, that create remarkable patterns of orientation and cell densification.

Bacterial adhesion to host cells is often a first step in the infection process. For example, Escherichia coli causes urinary tract infections that begin when E. coli bind to host bladder-epithelial cells and initiate invasion. There is growing interest in developing new antimicrobials that target mechanisms promoting infection, such as binding to host cells. This new therapeutic strategy requires a detailed understanding of the factors that contribute to bacterial adhesion. To address this issue, we developed a live cell monolayer rheometer to measure adhesion between a monolayer of bladder-epithelial cells and a layer of bacteria, as a function of bacterial production of different extracellular components.