Fig. 4: Epithelial mechanical properties and its environment condition on actin stars development.

A Confocal analysis of the basal actin arrangement in organoid-derived monolayer grown on 300 Pa, 2.4 or 5.2 kPa polyacrylamide (PAA) gels. Scale bar, 10 μm. B Statistical analyses of basal actin-based structures formed on different rigidity PAA gels. Mean AcS proportion at 300 Pa = 93 ± 4.33% (mean+S.E.M), at 2.4 kPa = 17 ± 10.02% and at 5.2 kPa = 0 ± 0%. Mean actin aster lattice proportion at 300 Pa = 5 ± 2.33%, at 2.4 kPa = 67 ± 14.58%, at 5.2 kPa = 48 ± 14.86%. Mean actin stress fibres proportion at 300 Pa = 3 ± 3%, at 2.4 kPa = 16 ± 11.12%, at 5.2 kPa = 52 ± 14.86% N = 3 experiments, n (300 Pa) = 107 cells, n (2.4 kPa) = 160 cells, n (5.2 kPa) = 229 cells. Two-sided Fisher’s exact test, ****p = 5.32 × 10⁻⁵⁷. Source data are provided as a Source Data file. C Confocal analysis of basal actin (green) and paxillin (magenta) in Caco2 cells grown on glass coverslips, uncoated or on cross-linked (CL) Matrigel, and treated with either DMSO (control) or 20 nM calyculin-A. Cells stained with phalloidin and paxillin show actin (green) or focal-adhesion (magenta) organization respectively. Nuclei (blue) are stained with Hoechst33342. Scale bar, 5 μm. Blue arrows show AcS nodes in Caco2 cells. Scale bar, 2 μm. Images are representative of three independent experiments. D Scheme showing the micropatterned substrates used for Caco2 monolayer culture in adhesive (blue)/non-adhesive (white) conditions. Created in BioRender. Delacour, E. (2025) https://BioRender.com/6fr6i4v. E Confocal analysis basal distribution of actin (green) and E-cadherin (magenta) in Caco2 cells grown on adhesive/non-adhesive micropatterns. Red dotted lines delimit the adhesive from the non-adhesive areas. The blue boxed region is enlarged in the lower panel. Blue arrows in the inset indicate AcS nodes. Nuclei (blue) are stained with Hoechst33342. Scale bars, upper row 10 μm, lower row 5 μm. Images are representative of three independent experiments.