MUC5AC and colitis: A. muciniphila significantly increased the expression of epithelial tight junction protein Occludin, the number of Ki67+ proliferating cells, the number of goblet cells, the expression of mucin protein (MUC2) secreted by goblet cells, and decreased the number of cleaved caspase−3+ apoptotic cells, compared with the control group (Figure S2A−E), indicating a protective effect on the intestinal barrier in DSS-induced colitis model.