FIGURE 5.

Caveolin-1 knockdown does not prevent strain activation of kinase and gene targets. A, caveolin-1 protein levels were decreased by treatment with siRNA targeting caveolin-1 for 48 h. B, Western blot showed that caveolin-1 knockdown did not inhibit strain activation of Akt. Strain-induced inactivation of GSK3β, shown by the increase of phospho-GSK3β (Ser⁹), was enhanced after strain for 30 min when caveolin-1 expression was decreased. The base-line levels of phospho-Akt (Ser⁴⁷³) and phospho-GSK3β (Ser⁹) were decreased in cells transfected with siCav. Representative blotting is shown here. Averaged densitometries (mean ± S.E.) for phosphorylated proteins from three experiments are shown in the graphs. C, real time RT-PCR after 4 h of mechanical strain in cells transfected with control siRNA (siSCR) or siCav. The strain effect on WISP1 expression was masked in cells transfected with siSCR. Increases in WISP1 and RUNX2 gene expression by strain were seen in cells treated with siCav. Eight experiments grouped (mean ± S.E.) for statistical analyses are shown in the graph. ^*, significant effect of strain (p < 0.01).