Fas and Fas ligand in gut and liver

Apoptosis (programmed cell death) has been shown to play a major role in de velopment and in the pathogenesis of numerous diseases. A principal mechani sm of apoptosis is molecular interaction between surface molecules known as the "death receptors" and their ligands. Perhaps the best-studied death re ceptor and ligand system is the Fas/Fas ligand (FasL) system, in which Fast , a member of the tumor necrosis factor (TNF) family of death-inducing liga nds, signals death through the death receptor Fas, thereby resulting in the apoptotic death of the cell. Numerous cells in the liver and gastrointesti nal tract have been shown to express Fas/FasL, and there is a growing body of evidence that the Fas/FasL System plays a major role in the pathogenesis of many liver and gastrointestinal. diseases, such as inflammatory bowel d isease, graft vs. host disease, and hepatitis. Here we review the Fas/FasL system and the evidence that it is involved in the pathogenesis of liver an d gastrointestinal diseases.