Fig. 3. FXR activity contributes to GVHD.

(a, b) Stably transfected HepG2 cells expressing luciferase under the control of an FXR-responsive element were treated with the indicated BAs for 16h. Endpoint luciferase activity was normalized by live cell numbers determined by Hoechst 33342 staining. (a) Assay in agonist mode. FXR activation induced by the indicated BAs at 100μM. Showing % of FXR activity relative to the positive control (CDCA). (b) Assay in antagonist mode. FXR activation induced by a suboptimal concentration of CDCA (50μM) was counteracted by equimolar amounts of the indicated BA or the synthetic FXR antagonist DY268 (20nM). Showing % of FXR activity relative to the positive control (CDCA). (c-e) Lethally irradiated BALBc mice received B6 BM alone (BM) or in combination with T cells (BM+T). (c) Survival of BALBc mice that were treated with the FXR agonist GW4064 30mg/kg intraperitoneally once daily or vehicle for 15 days starting day −1 relative to transplant. (d) Survival of BALBc mice transplanted with donor T cells from either Nr1h4^fl/fl (BM+T^WT) or Cd4-Cre Nr1h4^fl/fl (BM+T^ΔFXR) mice on a B6 background. (e) Survival of 129S mice transplanted with B6 BM+T^WT or T^ΔFXR. (a, b) Data shown as mean ± S.D, pooled from two independent experiments carried out in technical triplicates. Statistical significance in (a, b) was determined by a one-way ANOVA followed by the Dunnett’s multiple comparisons test. Data combined from two (c, e, n=20) or three (d, n=30) independent experiments. Statistical significance in (c-e) was determined using the log-rank test.