GDF-15 and TGF-β1–induced inhibition of integrin activation and leukocyte transmigration depend on CalDAG-GEF1. (A) PMNs from either WT or CalDAG-GEF1−/− mice were incubated for 20 minutes with GDF-15 or TGF-β1 (100 ng/mL), followed by CXCL1 (100 ng/mL) for 3 minutes at 37°C (where indicated) before binding of soluble ICAM-1-Fc (1.5 μg/1 × 106 cells) and α-human IgG-APC antibody (0.75 μg/1 × 106 cells) was determined by flow cytometry. (B) Transendothelial migration of PMNs from WT or CalDAG-GEF1−/− mice (as indicated) through a TNF-α–stimulated bEnd.5 cell monolayer in transwell filters along a CXCL1 chemotactic gradient was analyzed after preincubation of the cells with 100 ng/mL of GDF-15 or 100 ng/mL TGF-β1 (as indicated) for 20 minutes before transmigration. Data of 3 independent experiments were pooled (A-B). Data are shown as mean ± SEM. *P < .05; **P < .01; ***P < .001.
