To examine the effects of tanshinone IIA, the main effective component of Salvia miltiorrhiza (known as 'Danshen' in traditional Chinese medicine) on angiotensin II (Ang II)-mediated cardiomyocyte apoptosis. Rat neonatal cardiomyocytes were primarily cultured with Ang II or Ang II plus tanshinone IIA. Myocyte apoptosis was evaluated by caspase-3 activity and DNA strand break level with TdT-mediated dUTP nick-end labeling (TUNEL) staining. Western blot analysis was employed to determine the related protein expression and flow cytometry assay was used to determine the TUNEL positive cells and the intracellular reactive oxygen species (ROS) production. SiRNA targeted to Akt was used. Ang II (0.1 μmol/L) remarkably increased caspase-3 activity, TUNEL positive cells, and cleaved caspase-3 and cytochrome c expression, but reduced Bcl-X_L expression. These effects were effectively antagonized by pretreatment with tanshione IIA (1−3 μmol/L). Tanshinone IIA had no effect on basal ROS level, while attenuated the ROS production by Ang II. Interestingly, tanshione IIA significantly increased the phosphorylated Akt level, which was countered by the PI3K antagonist wortmannin or LY294002. Knockdown of Akt with Akt siRNA significantly reduced Akt protein levels and tanshinone IIA protective effect. Tanshinone IIA prevents Ang II-induced apoptosis, thereby suggesting that tanshinone IIA may be used for the prevention of the cardiac remodeling process.

Urotensin II (U-II), an 11-amino acid peptide, exerts a wide range of actions in cardiovascular systems. Interleukin-8 (IL-8) is secreted by endothelial cells, thereby enhancing endothelial cell survival, proliferation, and angiogenesis. However, the interrelationship between U-II and IL-8 as well as the detailed intracellular mechanism of U-II in vascular endothelial cells remain unclear. The aim of this study was to investigate the effect of U-II on IL-8 expression and to explore its intracellular mechanism in human umbilical vein endothelial cells. Primary human umbilical vein endothelial cells were used. Expression of IL-8 was determined by real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and luciferase reporter assay. Western blot analyses and experiments with specific inhibitors were performed to reveal the downstream signaling pathways as concerned. U-II increased the mRNA/protein levels of IL-8 in human umbilical vein endothelial cells. The U-II effects were significantly inhibited by its receptor antagonist [Orn⁵]-URP. Western blot analyses and experiments with specific inhibitors indicated the involvement of phosphorylation of p38 mitogen-activated protein kinase and extracellular signal-regulated kinase in U-II-induced IL-8 expression. Luciferase reporter assay further revealed that U-II induces the transcriptional activity of IL-8. The site-directed mutagenesis indicated that the mutation of AP-1 and NF-kB binding sites reduced U-II-increased IL-8 promoter activities. Proliferation of human umbilical vein endothelial cells induced by U-II could be inhibited significantly by IL-8 RNA interference. The results show that U-II induces IL-8 expression in human umbilical vein endothelial cells via p38 mitogen-activated protein kinase and extracellular signal-regulated kinase signaling pathways and IL-8 is involved in the U-II-induced proliferation of human umbilical vein endothelial cells.