Lowering Caveolin-1 Expression in Human Vascular Endothelial Cells Inhibits Signal Transduction in Response to Shear Stress
Figure 3
Activation of Akt and
ERK1/2 in response to shear stress. HUVECs were transfected with either
caveolin-1 siRNA, negative control siRNA, or left untreated. 48 hours after
transfection, cells were subjected to a shear stress of approximately 15 dyn/ for 10 minutes. (a) After treatment, cells were lysed, and the amount of
phosphorylated Akt and ERK1/2 was determined by immunoblotting. Equal loading
of proteins of each transfection condition was ensured by detecting the
unrelated metabolic enzyme GAPDH on the same blot. The phosphorylation status
of statically cultured cells is shown as a reference. (b) Quantification of the
signal intensities in the immunoblot assay. Each bar represents the average
intensity of four separate experiments. Error bars denote standard deviation.
Akt and ERK1/2 phosphorylations increase five- to tenfold when untreated cells
are subjected to shear stress. Both Akt and ERK1/2 phosphorylations are
significantly lower (, , Student’s -test)
when cells are treated with caveolin-1 siRNA instead of negative control siRNA
prior to subjecting the cells to shear stress. No significant difference was
detected between untreated cells and cells transfected with negative control
siRNA, showing that the transfection procedure itself has no influence. Graphs
represent the averages of four separate experiments.
