The expression levels of genes involved in classical and alternative bile acid synthetic pathways such as CYP7A1, CYP7B1, CYP27A1, and CYP8B1 were significantly lower in the liver of DSS-induced colitis mice than those of non-colitis controls, accompanied with a reduction in expression of bile acid transporter BSEP (Fig. 4F). Here, CYP7A1 is linked to colitis.