Shear forces induce ICAM-1 nanoclustering on endothelial cells that impact on T-cell migration
The leukocyte-specific ß2-integrin LFA-1 and its ligand ICAM-1, expressed on endothelial cells (ECs), are involved in the arrest, adhesion, and transendothelial migration of leukocytes. Although the role of mechanical forces on LFA-1 activation is well established, the impact of forces on its major ligand ICAM-1 has received less attention. Using a parallel-plate flow chamber combined with confocal and super-resolution microscopy, we show that prolonged shear flow induces global translocation of ICAM-1 on ECs upstream of flow direction. Interestingly, shear forces caused actin rearrangements and promoted actin-dependent ICAM-1 nanoclustering before LFA-1 engagement. T cells adhered to mechanically prestimulated ECs or nanoclustered ICAM-1 substrates developed a promigratory phenotype, migrated faster, and exhibited shorter-lived interactions with ECs than when adhered to non mechanically stimulated ECs or to monomeric ICAM-1 substrates. Together, our results indicate that shear forces increase ICAM-1/LFA-1 bonds because of ICAM-1 nanoclustering, strengthening adhesion and allowing cells to exert higher traction forces required for faster migration. Our data also underscore the importance of mechanical forces regulating the nanoscale organization of membrane receptors and their contribution to cell adhesion regulation. ; The authors thank T. van Zanten, E. Gutierrez and F. Campelo for useful discussions, J. Andilla from the SLN facility at ICFO for his support with STED imaging, and M. Rivas for technical assistance. This work was supported by the Human Frontiers Science Program (HFSP) (GA RGP0027/2012) and European Union H2020 Framework Programme under European Research Council Grant 788546 – NANO-MEMEC. M.F.G.-P. acknowledges support from the Government of Spain (FIS2017-89560-R; Severo Ochoa CEX2019-000910-S), Fundació Cellex, Fundació Mir-Puig, and Generalitat de Catalunya (CERCA, AGAUR Grant No. 2017SGR1000). I.K.P. acknowledges the support of the Grant No. POIR.04.04.00-00-3F2E/17- 00 which is carried out ...