Figure 3.

ETV2 (ETS variant 2) overexpression in adventitial Sca1⁺ (AdvSca1) cells promotes angiogenesis. A, LV H2b-RFP (red fluorescent protein) stably transduced AdvSca1, adventitial Sca1⁺ cells differentiated in serum replacement (SR) and transduced with null virus (Adv-null), or adventitial Sca1⁺ cells differentiated in SR and transduced with ETV2 virus (Adv-ETV2) cells were used for in vivo matrigel plug assays. Adv-ETV2 cells formed a denser network of capillary-like structures (black arrows) compared with the 2 other groups (*P<0.05; 5 microscope fields were counted for each plug; n=5 plugs for each population). RFP Adv-ETV2 express VE-cadherin (green) in newly formed capillaries after immunofluorescence staining. B, Representative bright field pictures and quantification of vascular sprouting observed with aortic ring explants from ApoE Sca1-GFP (green fluorescent protein) mice cultured with ETV2 overexpressing adenovirus compared with the control null adenovirus (n=18 rings for each group from 3 independent arteries/experiments; *P<0.05). C, Quantification of GFP⁺cd31⁺ cells (n=5 rings from 2 independent arteries/experiments; *P<0.05). D, Representative pictures of aortic ring explants from Sca1-GFP transgenic mice, stained for cd31 (red) after culture with ETV2 overexpressing adenovirus. Arrows indicate cd31-positive GFP cells.