Figure 3. CXCR7+ EC are defective in barrier formation. pLEC were infected with Trans or Trans+CXCR7. (A) At 20 h post-infection cells were trypsinized and replated onto ECIS arrays with or without SDF-1/CXCL12 at 10 ng/ml and allowed to attach for 25 h. Impedance readings at 4000 Hz were taken every 8 s throughout the timecourse. Individual wells were normalized to impedance at t = 0 and duplicate wells were averaged to create the impedance curves. Data are representative of duplicate wells from three independent experiments. (B) At the time of ECIS seeding, a subset of cells was reserved for analysis of CXCR7 and CXCR4 expression by flow cytometry. Necrotic cells were excluded from the analysis via propidium iodide staining and scatter characteristics. (C) Duplicate multi-well plates seeded identically to ECIS arrays were fixed at 25 h post-seeding and stained for CXCR7 (red), PECAM-1 (green), and DAPI and analyzed by deconvolution microscopy.