Dynamic filopodial forces induce accumulation, damage, and plastic remodeling of 3D extracellular matrices
Fig 1
Non-elastic remodeling occurs in the course of minutes and depends on crosslinking in 3D biopolymer networks.
(a) Z-projected confocal images of human cells including HUVECs and MDA-MB-231s suspended in 3D biopolymer networks of fibrin (3 mg/mL) and collagen (1.5 mg/mL), respectively. For fibrin gels, crosslinking was lowered using a transglutaminase inhibitor (DDITS, 0.2 mM). White arrows indicate the assumption of the type of deformation, overall (elastic and non-elastic) or elastic only, expected between two force configurations. Scale bar, 20 μm. (b, c) Quantification of the effect of crosslinking in terms of (b) displacement length (N = 8 cells per condition) and in terms of (c) densification factor (N = 7 cells per condition). Times (1h, 2h, 3h and 4 hours) are defined as the time after Cytochalasin D is removed and prior to decellularization. Decell. indicates at least 1 hour after decellularization. (d) Representative ECM remodeling dynamics by MDA-MB-231 cells for two different collagen gel densities. To assess the dynamics without the possible delay in force generation due to drug washout, Cytochalasin D pre-treatment was not used in these experiments. The average matrix displacement length in a ROI (~30x30 μm2) containing the cell and the newly recruited ECM fibers is obtained starting at the reference configuration shortly after seeding. These relatively fast dynamics measurements are calculated from time-lapse images of projected z-stacks. (e) Summary of RI for all cell-matrix pairs studied.