Fig. 8

hUC-MSC transplantation enhances gut microbiota-related metabolites that may ameliorate intestinal injury in MRL/lpr mice through the activation of AHR in intestinal epithelial cells. A–D Molecular docking diagrams of four metabolites with the aryl hydrocarbon receptor (AHR): 3-indoleacrylic acid (A), tributyrin (B), 1-acetylindole (C), and 5-methoxyindoleacetate (D). E Representative images of colons from the Ctrl, MSC, and MSC-FMT groups. F Representative images of colonic H&E staining in each group. Scale bars are 100 µm (overview) and 50 µm (magnified insets). G Intestinal zonula occludens 1 (ZO-1) and AHR fluorescence images and quantitative analysis results. Representative immunofluorescence images of ZO-1 (a) and AHR (b) in colons from Ctrl, MSC, and MSC-FMT-transplanted mice. Scale bars are 100 µm (overview) and 50 µm (magnified insets). Quantitative analysis of ZO-1 levels (c). Quantitative analysis of AHR levels (d). N = 7 per group. *P < 0.05, ***P < 0.001. H Key metabolite treatments enhance AHR gene expression and downstream pathway activation in HT-29 cells. RT-PCR quantification of relative gene expression for AHR, CYP1A1, and CYP1B1 in HT-29 cells after 24-h exposure to 3-indoleacrylic acid (a–c), 1-acetylindole (d–f), and tributyrin (g–i) at 0, 10, 50, 100, and 200 μM concentrations. N = 4 per group. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001