Fig. 2: Cells dynamically align in the tension direction via an active actin-dependent process.
From: Interplay of actin nematodynamics and anisotropic tension controls endothelial mechanics
a, Channel diameter as a function of time after the pressure increase (t = 0), colour coded for time (n = 6). b, Relative diameter change when increasing pressure from 150 Pa to 650 Pa (yellow, n = 21) and when decreasing pressure back to 150 Pa after 7 h later (orange, n = 21) (i). The diameter fluctuations at 150 Pa are shown in grey as a reference (Ctr). Evolution of the channel diameter between 6 h and 8.5 h for control monolayers (orange, n = 3) and for monolayers treated with cytochalasin D at t = 7 h (green, n = 3) under a pressure of 650 Pa, showing a sudden diameter increase due to actin depolymerization (ii). c, Endothelium stained for phalloidin at t = 0 h under 150 Pa (i) and after t = 7 h under 650 Pa (ii), where the orientation of the actin stress fibres is colour coded. Evolution of the probability distribution of the actin stress fibre orientation (iii) and the associated nematic order parameter q (iv) at 0 h (yellow, n = 8), 7 h (orange, n = 9), 24 h (red, n = 5) and 56 h (purple, n = 2). d, Endothelium stained for VE-cadherin at t = 0 h under 150 Pa (i) and after t = 7 h under 650 Pa (ii), with the orientation of the junctions colour coded. Nuclei are overlaid in white. Evolution of the probability distribution of the cell orientation (iii) and the associated nematic order parameter Q (iv) at 0 h (yellow, n = 8), 7 h (orange, n = 7), 24 h (red, n = 5) and 56 h (purple, n = 2). e, Probability distribution of the division orientation for monolayers, measured at t = 7 h, under low pressure (ΔP ≈ 150 Pa, yellow) and high pressure (ΔP ≈ 650 Pa, orange). f, Cytochalasin-D-treated monolayer stained for VE-cadherin after 7 h of pressure showing round cells (i). Evolution of the probability distribution of the cell orientation (ii) and the associated nematic order parameter Q (iii) before pressure increase (150 Pa, n = 8), and after 7 h of high pressure for the control (650 Pa, n = 7) and cytochalasin-D-treated (CytoD, n = 3) monolayers. Schematic showing round cells after actin depolymerization by cytochalasin D treatment, despite the circumferential stretching force (iv). Scale bar, 50 μm.
