MUC5AC and colitis: These include Muc1, a cell surface mucin that is upregulated in bacterial induced colitis [19] and potentially cleaved to release its α-subunit containing the extracellular mucin domain into the intestinal lumen, as seen during H. pylori infection [77]; Muc4 which can be up-regulated during DSS-induced colitis [78]and be expressed by colonic goblet cells [55]; and the secreted gel-forming mucins Muc19 and Muc6, the latter being produced in Muc2−/− mice during colitis [29].