Figure 1

The periodic curvature of the substrate linearly controls the epithelium elongation. (a) transversal cross-section of topographies I to V (orange: F-actin, magenta: nuclei, cyan: fibronectin). Note the decreasing curvature at the ridge/groove junctions. Note that cells can fit entirely on the ridges or grooves. (b) Representative outlines of epithelial monolayers after 48 h of growth on the surfaces shown in A. The surface longitudinal axis is oriented horizontally. The size of the outlines has been normalized to allow easier comparison of the shapes. (c) Schematic of the morphological parameters quantified. In blue, the ellipsoidal epithelial colony after 2 days of growth. The colony alignment with the topography is calculated as the α angle between the grooves and the longer axis of the colony. The colony elongation of the colony is the Aspect Ratio of the colony longer axis D to the shorter axis d. (d) Epithelial colony alignment with the topography as explained in C (mean + SEM). Five to 9 independent colonies per topography. The colony orientations on the 5 topographies are all statistically significant compared to flat (a one-way ANOVA followed by Tukey multiple comparison tests showed a statistical difference between the topographies and the flat control, P < 0.0001). (e) Epithelial colony elongation after two days of growth as a function of the maximal convex (left) or concave (right) curvature of each surface (see Supplementary Fig. S1 and Experimental Section for curvature calculation). Five to 9 independent colonies (mean + SEM). Linear regression: Elongation = 1.505 × Convex + 1.235, R² = 0.90 1; Elongation = − 3.441 × Concave + 1.212, R² = 0.9124. Dotted lines: 95% confidence interval of the linear regressions. (f) Epithelial colony elongation after 2 days of growth as shown in (e) normalized by the growth of the colony. The growth is defined by (A − A₀)/A₀ with A being the colony area at day 2 and A₀ the colony area at day 0.