Fig. 7: LCA promotes EcN biofilm formation on human colonic epithelial monolayers.

A Experimental schematic for testing the effect of LCA on EcN adhesion to the intestinal epithelium. Colonic organoids were derived from intestinal adult stem cells and expanded in 3D culture in multi-well plates before being dissociated and seeded on Transwell membranes to form monolayers. Following differentiation of the monolayers, EcN was added to the apical chamber. The schematic was created in Biorender. B A representative organoid monolayer stained for intracellular Muc2 (red) to mark goblet cells, overlaid on a phase contrast image, following 5 days of differentiation. Scale bar = 500 µm. C Representative images of GFP-expressing EcN adhering to organoid monolayers after 8 h of co-culture in the presence of 1% DMSO, 100 µM LCA, or 100 µM CDCA. The apical surface of the monolayers was washed three times with PBS prior to imaging to remove non-adherent bacteria. Scale bars = 500 µm. D Quantification of the GFP signal from the experiment shown in (C) following lysis and homogenization of each well. *** p < 0.001 (ANOVA followed by Tukey HSD).