Fig. 3: Compression is an intrinsic property of CAFs.

a PAA pillars containing fluorescent beads (gray). Top, 3D view. Bottom, lateral view. Scale bar, 100 µm. b 3D rendering of CAFs stained for F-actin (phalloidin, magenta) and DNA (DAPI, cyan) surrounding a pillar (fluorescent beads, green). Scale bar, 100 µm. N = 2 independent experiments. c Top, x-z pillar cross-section (fluorescent beads, green) surrounded by CAFs (F-actin, magenta; DNA, cyan). Dashed line represents two selected x-y planes shown at the bottom (1 and 2). Scale bars, 100 µm. N = 2 independent experiments. d Maximum intensity projection of CAFs surrounding a pillar and stained for F-actin (phalloidin, green), active myosin (pMLC, magenta) and DNA (DAPI, blue). Inset, magnified boxed region showing staining for pMLC and F-actin. Scale bar, 100 µm. e Cross-section of a representative (from n = 9 pillars, N = 2 independent experiments) pillar at its base, in the presence of CAFs (magenta) and after removal of CAFs (trypsin, cyan). Inset, magnified boxed region. Scale bar, 50 µm. f Representative unwrapped pillar (from n = 9 pillars, N = 2 independent experiments) showing CAFs occupancy (top, magenta) and 3D traction force maps (bottom). Color map represents normal tractions (compression is defined as negative, pulling is defined as positive); yellow vectors represent tangential tractions. g Representative 3D mapping of deformations (orange) and traction forces (black arrows) exerted by CAFs on a pillar, from n = 9 pillars, N = 2 independent experiments). Top (left) and side (right) views. Deformations are magnified 5 times for visualization purposes. h CAFs normal tractions averaged across pillar height, on a representative pillar before (magenta) and after (blue) blebbistatin treatment. Scale vector, 600 Pa. Right dot plot, quantification of mean normal tractions for each pillar before and after blebbistatin. n = 9 pillars, from N = 2 independent experiments.