Fig. 2.

Decrease of cell contractility increases contact guidance on soft topographical grooves and ridges. (A) Paxillin immunostaining of fibroblast on grooves of 3 ​kPa and 145 ​kPa. Examples of lamellipodial regions used for focal adhesion analysis is highlighted in yellow. Scale bar, 10 ​μm. (B) Focal adhesion area, (C) percentage of aligned focal adhesions as a function of increasing substrate stiffness in the laboratory framework and (D) percentage of aligned focal adhesions as a function of increasing substrate stiffness vis-à-vis the main cell axis direction. Grey area in (C and D) corresponds to values above the expected for a random distribution. N ​≥ ​3 experiments per condition and n ​≥ ​15 ​cells per condition. (E) Representative fluorescent images of 3T3 fibroblast treated with 20 ​μM Y-27632 on 2 ​μm wide grooves. Scale bar, 20 ​μm. (F) Cell elongation and (G) cell alignment index as a function of the substrate stiffness. N ​≥ ​3 experiments per condition and n ​≥ ​14 ​cells per condition. (H) Representative fluorescent image of the actin and tubulin cytoskeletons of 3T3 fibroblast treated with 20 ​μM Y-27632 on 2 ​μm wide grooves. Scale bar, 10 ​μm. See Tables S4–S5 for the exact number of cells and experiments. Data points (Mean ​± ​SE) in (B - D) and in (F) and (H) were fitted as an eye-guide. Statistical significance was assessed by Tukey's tests (F and G), Welch's test (B) and Kruskall-Wallis’ test (C and D). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)