Abstract
Farnesoid X receptor (FXR) is a ligand-activated nuclear hormone receptor expressed in the gastrointestinal tract, with high expression levels in the intestinal epithelium. Previously we have shown that FXR agonists with sustained activity decreased colitis in multiple chronic IBD models (i.e. Adoptive transfer colitis, Mdr1a-/- colitis, and SAMP1/YitFc ileitis). Because FXR agonists are dosed orally and do not have systemic immunosuppressive properties, they represent a novel and differentiated therapeutic approach for IBD. MET642 is an optimized, potent non-bile acid FXR agonist with sustained FXR activation. In this study, we examined the efficacy of MET642 in therapeutic treatment mode in adoptive T-cell transfer model.
Colitis was induced by transplanting CD4+CD45RBhi T-cells to recipient C.B-17 SCID mice. Body weights were monitored throughout study duration. Staring 21 days after T-cell transfer, mice were treated with vehicle (n=10), MET642 (0.1, 0.3 or 1 mg/kg p.o., daily, n=10), or anti-IL-12p40 (neutralizing both IL-12 and IL-23, 0.5mg/mouse, i.p., weekly, n=5) for 4 weeks. Terminal endpoints included colon weight to length ratio (W/L), colon histopathology and gene expression. Histopathology scores were determined for inflammation, erosion, gland loss and hyperplasia, each with a score of 0–5, and cumulative sum score of 0–20.
CD4+CD45RBhi T-cell transfer led to a significant reduction in body weight and increase in colon W/L ratio; both were reversed by MET642 and anti-IL-12p40. All dose levels of MET642 significantly improved the histopathology sum score relative to vehicle treatment, with maximal efficacy reached at 0.3mg/kg. Similar to anti-IL-12p40, MET642 showed improvements across all individual histopathology endpoints. Gene expression analysis suggests FXR activation increases anti-microbial activity, improves gut barrier and transporter function, and suppresses inflammation.
MET642, an oral once daily FXR agonist, significantly improved colitis in the adoptive T-cell transfer model. Activation of FXR by MET642 potentially promotes pathways of gut anti-microbial function, barrier function, and suppression of inflammation. These findings support further development of MET642 as a novel oral therapeutic for treating IBD.
