TNF and Crohn ileitis: To test this, we investigated the impact of celastrol on Tregs both in vitro and in vivo, evaluating its efficacy in HSF1<sup>fl/fl</sup>-CD4<sup>cre</sup> mice, and in two murine models of IBD: the adoptive transfer colitis, and TNF<sup>ΔARE+/-</sup> ileitis.