Endothelial responses to mechanical micro-wounding. (a) Schematic of a mechanical probe cell micro-wounding apparatus to locally disrupt membrane (blue), cytoskeleton (red), and adhesions (green). (b) Live imaging of MVEC micro-wound formation and healing. (i) Initial wound rapidly expands to ∼20 µm diameter (0–80 s). Multiple nodes of individual VL (arrowheads) as well VW form around the pore and propagate toward and across it to restore an intact endothelium. (ii) An individual VL formed adjacent to the wound edge shows doubling of membrane signal and close substrate contacts (IRM). (iii) A parent actin filament (dashed blue line) is shown that is radially oriented with respect to the wound. As the wound expands and the cell locally retracts toward the filament a node of actin accumulates on it and transitions to a VL. See Video 5. Bars, 5 µm.