Fig 2: TGR5 was involved in gastric intestinal metaplasia (IM) development.a Immunohistochemical staining of normal and IM tissues showing TGR5 expression. Scale bar, 100 µm (upper) and 50 µm (lower). b Column charts showed the cases with high and low TGR5 expression in IM tissues. **P < 0.01. c GES-1 cells were treated with SB756050 (2, 5, and 10 µM) for 24 h. Then, KLF4 and CDX2 protein expression was examined by WB. d GES-1 cells were transfected with TGR5 overexpression lentiviral. TGR5, KLF4, CDX2, and ALPI mRNA and protein levels were analyzed by qRT-PCR and WB. Error bar indicates the SEM, **P < 0.01 vs. NC, n = 3. e AGS cells were transfected with siRNAs target TGR5 for 72 h. Then TGR5, KLF4, and CDX2 protein expressions were examined by WB. f Further, TGR5 was knocked down by transfection with siRNA in GES-1 cells. Next, the cells were treated with DCA (200 µM) for 24 h. TGR5, KLF4, and CDX2 were examined by WB.

Fig 3: TGR5 expression was positively correlated with HNF4a and metaplasia markers in IM tissues.a IHC analysis of gastritis and IM tissues showed TGR5, HNF4a, KLF4, and CDX2-positive staining. Scale bar, 100 µm (upper) and 20 µm (lower). b HNF4a, CDX2 and KLF4 H-score in gastritis and IM tissues were compared. Error bars indicate 95% CI. **P < 0.01. c Correlation between HNF4a, CDX2, and KLF4 with each other in IM tissues by Spearman’s correlation analysis. d HNF4a, CDX2, and KLF4 H-score in gastritis and IM tissues were compared according to high and low TGR5 expression. Error bars indicate the mean ± SEM. **P < 0.01.

Fig 4: Aberrant CDX2, E-cadherin, and N-cadherin expressions illustrated the outcomes in CRC patients for OS. (a, b) Cumulative OS differences between patients with high level of CDX2 and E-cadherin. (c, d) High expressions of N-cadherin and CA199 are correlated with poor prognosis in CRC samples for OS.

Fig 5: BAs promote gastric intestinal metaplasia by upregulating CDX2 and MUC2 expression via the FXR/nuclear factor-?B signalling pathway. BAs enter the cell by active transport or by diffusion and induce the upregulation and nuclear location of p50/p65 expression. Nuclear p50 binds to the CDX2 promoter and promotes CDX2 transactivation. The BA-induced increase in FXR expression enhances the binding of p50 to the CDX2 promoter. The CDX2 protein then binds to the MUC2 promoter and increases MUC2 transactivation. ASBT, apical sodium-dependent bile acid transporter; BA, bile acid; CDX2, caudal-related homeobox transcription factor 2; FXR, farnesoid X receptor; MUC2, mucin 2.