Ko et al. (2016) reported that TSG-6 is required for MSCs to induce a suppressive monocyte/macrophage population. In a mouse colitis model, BM-MSCs had a therapeutic function induced by dextran sodium sulfate (DSS) depending on the production of TSG-6, which polarized macrophages from the M1 to M2 type (Sala et al., 2015). MSCs have also been shown to regulate microglia by secreting TSG-6. In this case, murine BM-MSCs inhibited the production of TNF-a, IL-1β, iNOS, and IL-6 by BV2 microglia stimulated by LPS in a TSG-6-dependent manner (Liu et al., 2014). This evidence concerns the gene TNFAIP6 and colitis.