Figure 7. Arg-II, p38, and S6K1 form a positive regulatory circuit in senescent endothelial cells. Senescent HUVECs were transduced with rAd/U6-LacZshRNA as control, -Arg-IIshRNA, -p38αshRNA or -S6K1shRNA. Ninety six hours post transduction, cells were serum-starved overnight. Cell lysates were prepared and subjected to immunoblotting analysis with antibodies against phospho-p38-T180/Y182 (p-p38), total p38 (p38), Arg-II, phosphor-S6-S235/236 (p-S6), and total S6 (S6). Tubulin served as loading control. The bar graph presents the quantification of the immunoblotting analysis. n=5, **p<0.01, ***p<0.001 vs corresponding shRNA-LacZ group.