TGFB1 and fibrosis: The DSS/AIEC fibrosis model did not lead to a significant rise in insoluble collagen in either mouse strain (Fig. 4G and Supplemental Fig. 5), and fibrosis-associated Tgfb, Col1a, Loxl2 and Nox4 genes were either only slightly increased or not altered, and only minimally downregulated in Nox4−/− mice (Fig. 4I-L and Supplemental Fig. 5).