VEGFR2 Mediates Endothelial Permeability by OxPAPC Figure 3. Involvement of VEGFR2 in EC barrier dysfunction induced by high OxPAPC concentration. A – siRNA-induced VEGFR2 depletion in HAEC and HPAEC at mRNA and protein levels was compared to treatment with non-specific RNA. Membrane re-probing with b-tubulin antibodies was used as normalization control. B – HPAEC grown on gold microelectrodes for TER measurements were transfected with siRNA specific to VEGFR2 (100 nM). Control cells were transfected with non-specific RNA. After 72 hrs of transfection, cells were stimulated with OxPAPC (75 mg/ml, shown by arrow) or vehicle, and permeability changes were monitored over 6 hrs. C - Bar graphs depict TER changes measured after 4 hrs of Ox- PAPC stimulation marked by dotted line in panel B; n = 4–6 per condition; *p,0.05. doi:10.1371/journal.pone.0030957.g003 PLoS ONE | www.plosone.org 5 January 2012 | Volume 7 | Issue 1 | e30957