ATF5 and colitis: We next examined the role of ATF5 in promoting intestinal barrier function by measuring animal responses to dextran sulfate sodium (DSS), a chemical used to model colitis in rodents.42 We observed a greater loss of bodyweight and an increased disease activity index (DAI) score (a measure of colitis progression43) in Atf5ΔIEC mice after DSS administration (Figures 2I and 2J).