biostudies-literatureSun XNational Natural Science Foundation of China1023865https://www.ebi.ac.uk/biostudies/studies/S-EPMC9692129biostudies-literatureUnknown13Activation of integrins is crucial for recruitment of flowing leukocytes to inflammatory or injured vascular sites, but their spatiotemporal characteristics are incompletely understood. We discovered that β₂-integrin activation over the entire surface of neutrophils on immobilized P-selectin occurred <i>via</i> mitogen-activated protein kinase (MAPK) or non-MAPK signaling with a minute-level timescale in a force-dependent manner. In flow, MAPK signaling required intracellular Ca²⁺ release to activate integrin within 2 min. Integrin activation <i>via</i> non-MAPK signaling occurred first locally in the vicinity of ligated P-selectin glycoprotein ligand-1 (PSGL-1) within sub-seconds, and then over the entire cell surface within 1 min in an extracellular Ca²⁺ influx-dependent manner. The transition from a local (but rapid) to global (but slow) activation mode was triggered by ligating the freshly activated integrin. Lipid rafts, moesin, actin, and talin were involved in non-MAPK signaling. Fluid loads had a slight effect on local integrin activation with a second-level timescale, but served as enhancers of global integrin activation.Frontiers in immunologySpatiotemporal characteristics of P-selectin-induced β₂ integrin activation of human neutrophils under flow.PMC9692129Grant Nos. 11432006 (J.W.), 12072117 (J.W.), 12172137 (Y.F.), 82170566 (B.H.), 82000518 (B.H.)Fang YWu JPan YFang JLing YLi QWang HJi YLin JSun XHuang BGuo PfalseSpatiotemporal characteristics of P-selectin-induced β₂ integrin activation of human neutrophils under flow.Activation of integrins is crucial for recruitment of flowing leukocytes to inflammatory or injured vascular sites, but their spatiotemporal characteristics are incompletely understood. We discovered that β₂-integrin activation over the entire surface of neutrophils on immobilized P-selectin occurred <i>via</i> mitogen-activated protein kinase (MAPK) or non-MAPK signaling with a minute-level timescale in a force-dependent manner. In flow, MAPK signaling required intracellular Ca²⁺ release to activate integrin within 2 min. Integrin activation <i>via</i> non-MAPK signaling occurred first locally in the vicinity of ligated P-selectin glycoprotein ligand-1 (PSGL-1) within sub-seconds, and then over the entire cell surface within 1 min in an extracellular Ca²⁺ influx-dependent manner. The transition from a local (but rapid) to global (but slow) activation mode was triggered by ligating the freshly activated integrin. Lipid rafts, moesin, actin, and talin were involved in non-MAPK signaling. Fluid loads had a slight effect on local integrin activation with a second-level timescale, but served as enhancers of global integrin activation.2022-01-01T00:00:00Z20222025-04-19T17:28:24.818Z2025-04-19T17:28:24.818ZS-EPMC96921293643919010.3389/fimmu.2022.1023865