Figure 2. Silencing Arg-II or p38α reduces cytokine/chemokine secretion and recouples eNOS in senescent endothelial cells. Senescent HUVECs were transduced with control shRNA (rAd/U6-LacZshRNA), rAd/U6-Arg-IIshRNA or -p38αshRNA. Ninety six hours post transduction, cells were serum-starved overnight. Cell culture conditioned medium were collected for ELISA, and cell extracts were subjected to immunoblotting. (A) Immunoblotting analysis of Arg-II, phsopho-p38α–Thr180/Tyr182 (p-p38α) and total-p38α(p38α). Tubulin served as loading control. (B) Cytokine/chemokine secretion was determined by ELISA with collected conditioned medium. (C) DHE and DAF-2DA staining for detection of superoxide anions and NO, respectively. Quantification of the signals were presented in the bar graphics. n=4, *p<0.05, **p<0.01, ***p<0.001 vs shRNA-LacZ group. Scale = 200 μm.