Effect of reduced BMPR-II expression in HPAECs on leukocyte recruitment under static conditions. Mock-transfected HPAECs or HPAECs transfected with siRNA-targeting BMPR-II or nontargeting control siRNA were seeded onto Transwell filters, then unstimulated or stimulated with TNF-α for 4 hours or TGF-β1 for 24 hours. Neutrophil transmigration was assessed after 2 hours and shown as the change in the number of transmigrated neutrophils from mock-transfected HPAECs. Data are the mean ± SEM for 4 independent experiments. *P < .05, compared with NTCsi-transfected HPAECs by paired t test.