OCLN and colitis: Mice with DSS-induced colitis used in this study consistently showed decreased expression of ZO-1, occludin, MUC2, and MUC13 (Figs. 1F–H, 6G), and elevated level of plasma LPS (Figs. 1I, 6H), indicating an impairment of intestinal barrier functions and thereby increased intestinal permeability.