Figure 4 | Scientific Reports

Figure 4

From: Substrate Rigidity Controls Activation and Durotaxis in Pancreatic Stellate Cells

Figure 4

Durotactic response of PSCs. (a) Fluorescent image of rigidity boundary between soft (1 kPa) and stiff (25 kPa) PAA matrices. Yellow-green FluoSpheres were embedded into stiff hydrogels. (b) Representative example of PSC migration from soft to stiff regions over a 5-hour period. Scale bar 25 μm. Over time the cell (highlighted with a white arrow) moved towards the left (stiffer substrate). (c) Average cell migration distance observed at the rigidity boundary, soft region and stiff region of the hydrogel over a 12-hour period. Positive values indicate movement towards higher rigidity, values close to 0 indicate random, undirected movement. PSCs exposed to a stiffness gradient expressed a marked predilection towards stiff substrate, with those exposed to only a single rigidity exhibiting undirected, limited movement. Number of cells analysed per region: boundary – 51; soft – 67; stiff – 78. *p < 0.05. (d) Average cell movement speed observed at the rigidity boundary, soft region and stiff region of the hydrogel over a 12-hour period. PSCs exposed to a stiffness gradient exhibit markedly increased migratory speed when compared to PSCs exposed to only a single rigidity. Number of cells analysed per region: boundary – 51; soft – 67; stiff – 78. *p < 0.05, In all cases, histogram bars represent mean ± SEM. Data are representative of 3 independent experiments.