FIGURE 3.

β1-Integrin-collagen interaction suppresses the FoxO3a via PI3K/Akt pathway. A, human lung fibroblasts were preincubated with α1 to α5 and αv-integrin and/or β1-integrin blocking antibodies (1 μg/ml, respectively) for 45 min followed by the attachment to type I collagen for 30 min. FoxO3a levels were then measured. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as a loading control. B, serum-starved human lung fibroblasts were preincubated with PI3K (0.2 μm) or Akt inhibitor (1 μm) for 45 min. Cells were then ligated with β1-integrin activating antibody (3 μg/ml) for 60 min. FoxO3a expression levels were measured. TS2/16, β1-integrin activating antibody; PI3KI, PI3K inhibitor; AktI, Akt inhibitor; IgG, isotype control. C, serum-starved human lung fibroblasts were preincubated with Akt inhibitor (1 μm) for 45 min. Cells were then stimulated with β1-integrin activating antibody TS2/16 (3 μg/ml) as a function of time. FoxO3a and actin expression levels were then measured. IgG, isotype control.