MUC5AC and colitis: Lactobacillus reuteri was used as the control strain, since our data suggest that it did not display mucin-degrading capability (Figure S4), and we did not consider L. reuteri to increase intestinal permeability as it improves intestinal permeability due to colitis.16 Additionally, because the levels of L. reuteri were approximately equivalent to those of A. muciniphila in our murine models, we allowed L. reuteri to be used as the control.