Characterization of the role of the Fas-associated death domain (FADD) protein in lipopolysaccharide signalling in endothelial cells

Sepsis is a life-threatening medical condition caused by a severe bacterial infection. It is a leading cause of death in critically ill patients, with mortality rates reaching greater than 60 per cent in its most critical forms. Endothelial cells, the layer of cells that line the inside wall of blood vessels, are a primary target for bacteria during infection. Major components present on the surface of some types of bacteria are recognized by molecules on the surface of the endothelial cell and can trigger the cells to release a class of chemicals that initiate an inflammatory response, characterized by redness, heat, swelling and pain. Under normal conditions, the body will protect itself by initiating this response. However, sepsis occurs when there is hyperactivation of the inflammatory response and the body fails to resolve the infection. This can result in endothelial cell damage, leading to major organ failure and death. Lipopolysaccharide (LPS) is a large molecule that forms an integral part of the outer wall of some bacteria. Exposure to this molecule signals cells to activate the inflammatory response and, in the case of endothelial cells, leads to cell death. Shauna Dauphinee is investigating whether a protein called FADD (Fas associated death domain) decreases the signalling ability of LPS, thereby reducing the inflammatory response and causing cell death. The results of this research could ultimately lead to new ways to treat sepsis.