Fig. 4.

Thrombin treatment increases heterogeneity in the distribution of mechanical tension within the VEC monolayer and facilitates leukocyte diapedesis through Rho kinase pathway. (A) F-actin (red) and VE-Cadherin (green) staining of VECs. VECs were preincubated for 30 min in the absence or the presence of 30 μM of Y-27632 and followed for 1 h with the thrombin stimulation. (Scale bar, 50 μm.) (B) Permeability response after the junctional recovery is given as 1 h after thrombin treatment. T, thrombin; Y/T, Y-27632/thrombin. (C) Three-dimensional traction stresses and mechanical tension within the monolayer. (i) Maps showing representative spatial distributions of monolayer tension. (Scale bar, 50 μm.) (ii) Quantification of 3D stresses. (iii) Quantification of monolayer tensions. (D) Quantification of leukocyte diapedesis rates at the end point of the diapedesis assay. Bars represent average fraction of transmigrated cells. The data are expressed as mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001. The data are representative of four independent experiments with more than 100 cells per group.