Figure 6
Increased ECM coating density induces a decrease in migration speed and keratin flow. Data were extracted from confocal images (30 min recordings, 1 image.min−1; objective 63 x) of transiently transfected K5-YFP nHEKs migrating on glass with low (n = 14) or high fibronectin coating density (n = 10). (A) Column scatter plots show fibronectin density in relation to mean cell area (left) and mean cell eccentricity (right). Unpaired Student t-test for mean cell area (P = 0.8011) and Student t-test with Welch’s correction for mean cell eccentricity (P = 0.3966; n.s., not significant). Note that the cell morphology is not affected by different coating densities. (B) Graphical representation of migration characteristics in relation to coating density. At left, mean migration speed is shown (Mann-Whitney test; P = 0.0434); at right, the directionality ratio is depicted (unpaired Student t-test; P = 0.0017). An increase in coating density correlates with a decrease in migration speed and directionality. (C) Depicts relationship between keratin flow and fibronectin coating density. Unpaired Student t-test (P = 0.0029). (D) Graph of mean migration speed versus mean keratin flow. For a given migration speed, the corresponding keratin flow is similar irrespective of the coating density. Pearson correlation (low fibronectin coating density: P = 0.0063, R² = 0.4765; high fibronectin coating density: P = 0.0047, R² = 0.6530). (E) Heat maps showing the mean keratin flow in shape-normalized nHEKs migrating on low and high density fibronectin (n = 14 and n = 10, respectively). (F) Quantification of the effect of fibronectin coating densities on keratin flow in the cell front, center and back. Reduction is seen in all cell regions with the strongest decrease in the cell center. Unpaired Student t-test (P = 0.0174; front), Student t-test with Welch’s correction (P = 0.0044; center) and Mann-Whitney test (P = 0.0109; back). (G) The column scatter plots show keratin flow ratios in different cell regions at low and high fibronectin coating density. Unpaired Student t-test (P = 0.0684; front/back), Mann-Whitney test (P = 0.3641; front/center), and unpaired Student t-test (P = 0.0148; back/center). The figure is modified from57.
