 Epithelial tight junctions, TJs, regulate paracellular trafficking of macromolecules, form a selective permeable seal between adjacent epithelial cells, and demarcate the boundary between apical and basolateral membrane domains. Disregulation of TJ barrier integrity may predispose or enhance inflammatory bowel disease, IBD, progression, making therapeutic target to restore TJ barrier integrity a potential effective approach against IBD. This article was authored by Sung Hee Lee.