MSCs ameliorate DSS-induced colitis by suppressing Th1/Th17 cell responses and inducing Treg cells either by direct or indirect actions through the induction of M2 macrophages, which is mediated by PGE2 [79], TSG-6 [80,81], and the Fas ligand [47]. The gene discussed is TNFAIP6; the disease is colitis.