FIGURE 2.

GSK-3β inhibitors increase human airway smooth muscle cell size and protein synthesis. A, changes in human airway smooth muscle cell size after treatment with LiCl or SB216763. Cells were sorted by forward scatter. B, overall protein synthesis of human airway smooth muscle cells treated with LiCl or SB216763, as assessed by [³H]leucine incorporation (cpm/well). C, immunoblots for GSK-3β expression in cells transfected with GSK-3β or nontargeting siRNA (60 nm). D, changes in human airway smooth muscle cell size after treatment with GSK-3β siRNA (dashed line, nontargeting siRNA; solid line, GSK-3β siRNA). E, changes in protein synthesis with GSK-3β siRNA. F-H, CT-1 and TGF-β also induced cell hypertrophy, as indicated by a rightward shift in forward scatter and increased protein synthesis (dashed lines, control; solid lines, CT-1 or TGF-β; n = 3-5 for each group, mean ± S.E.; ^*, p < 0.05 relative to unstimulated cells or nontargeting siRNA, one-way ANOVA). I, effects of TGF-β, CT-1, and inhibitors of GSK-3β on human airway smooth muscle [³H]thymidine uptake, a measure of DNA synthesis (n = 3). 10% FBS was employed as a positive control.