VDR and colitis: Supplementation of certain BAs includingisoalloLCA has been shown to ameliorate inflammatory colitis through upregulating Treg via BA receptors.104,106 Meanwhile, some BAs, such as 3-oxoLCA and isoLCA, can suppress Th17 cell differentiation to inhibit colitis development.102–104 The importance of BA receptor pathways in controlling colitis is highlighted by the severe colitis observed in Vdr flox/floxFoxp3YFP-cre mice.106