Fig. 2.

Rac1 is involved in adenosine-mediated vasa vasorum endothelial cell (VVEC) barrier enhancement. A: adenosine increases Rac1 activity in VVEC. Cells were incubated with adenosine (100 μM) in serum-free medium for 5, 10, 15, and 30 min. Rac1 activation was measured using G-LISA Rac1 activity assay (cytoskeleton) according to the manufacturer’s instructions. Absorbance was read at 490 nm, and the background was subtracted. The data are expressed as means ± SE (n = 3 experiments), one-way ANOVA. *P < 0.05 compared with 0 min. B: overexpression of dominant-negative mutant Rac1 attenuates adenosine-induced barrier enhancement in VVEC. VVEC were seeded in electric cell substrate impedance-sensing arrays and transduced with adenovirus-containing green fluorescent protein (GFP) or dominant-negative mutant Rac1 (GFP-Rac1-N17). 24 h after transduction, VVEC were incubated in serum-free medium for 1 h and then stimulated with vehicle or adenosine (100 µM). Transendothelial electrical resistance was monitored for ~2.0 h. C: immunofluorescence images show the transduction efficiency (scale bar = 200 μm).