Many selenium-containing “selenoproteins” function as antioxidants, and work by our lab and others has demonstrated that selenoproteins often protect against intestinal inflammatory diseases, including colitis. Glutathione peroxidase 1 (GPx1) is a ubiquitous, mitochondrial and cytosolic selenoprotein which catalyzes the reduction of hydrogen peroxide by glutathione. Previously, we determined that despite its antioxidant role, loss of GPx1 greatly reduced disease severity in the dextran sodium sulfate (DSS) colitis model.