endothelin-1 and tanshinone

Tanshinone IIA (Tan IIA) may exert significant protective effects against heart oxidative stress damage in obstructive sleep apnoea (OSA) syndrome. Chronic intermittent hypoxia (CIH)-triggered left ventricular dysfunction is used in a rat model to mimic CIH in OSA patients. 48 rats were randomly divided into three groups: normal control (NC) group, CIH group and CIH+Tan IIA group with 16 rats in each group. At the end of experiment (day 21), the blood pressure, Plasma ET-1 and NO content, hemodynamic indexes, heart histology, myocardial apoptosis as well as the expression of eNOS, ET-1, ET

Topics: Abietanes; Animals; Apoptosis; Blood Pressure; Cardiotonic Agents; Chronic Disease; Electrocardiography; Endothelin-1; Heart Function Tests; Hemodynamics; Hypoxia; Male; Myocardium; Myocytes, Cardiac; Nitric Oxide; Nitric Oxide Synthase Type III; Rats, Sprague-Dawley; Receptor, Endothelin A; Receptor, Endothelin B; Signal Transduction; Systole

1. Tanshinone IIA, one of the active components of the Radix of Salvia miltiorrhiza, is used in traditional Chinese medicine to treat cardiovascular diseases. However, the intracellular mechanism of action of tanshinone IIA remain to be determined. The aims of the present study were to test the hypothesis that tanshinone IIA alters strain-induced endothelin (ET)-1 expression and nitric oxide (NO) production, as well as to identify the putative signalling pathways involved, in human umbilical vein endothelial cells (HUVEC). 2. Cultured HUVEC were exposed to cyclic strain in the presence of 1-10 μmol/L tanshinone IIA. Expression of ET-1 was examined by reverse transcription-polymerase chain reaction and ELISA. Phosphorylation of endothelial NO synthase (eNOS) and activating transcription factor (ATF) 3 was assessed by western blot analysis. 3. Tanshinone IIA (3 and 10 μmol/L) inhibited strain-induced ET-1 expression. In contrast, NO production, eNOS phosphorylation and ATF3 expression were enhanced by tanshinone IIA. The eNOS inhibitor N(G) -nitro-L-arginine methyl ester (l-NAME; 100 μmol/L), the phosphatidylinositol 3-kinase inhibitor LY294002 (5 μmol/L) and the soluble guanylyl cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ; 10 μmol/L) inhibited tanshinone IIA-induced increases in ATF3 expression. Moreover, treatment of HUVEC with either an NO donor (3,3-bis [aminoethyl]-1-hydroxy-2-oxo-1-triazene; 500 μmol/L) or an ATF3 activator (carbobenzoxy-L-leucyl-L-leucyl-L-leucinal; 5 μmol/L) resulted in the repression of strain-induced ET-1 expression. The inhibitory effect of tanshinone IIA on strain-induced ET-1 expression was significantly attenuated by l-NAME, ODQ and the transfection of small interfering RNA for ATF3. 4. In conclusion, tanshinone IIA inhibits strain-induced ET-1 expression by increasing NO and upregulating ATF3 in HUVEC. The present study provides important new insights into the molecular pathways that may contribute to the beneficial effects of tanshinone IIA in the cardiovascular system.

Topics: Abietanes; Activating Transcription Factor 3; Cardiovascular Diseases; Cells, Cultured; Cellular Microenvironment; Down-Regulation; Endothelin-1; Endothelium, Vascular; Enzyme Inhibitors; Guanylate Cyclase; Human Umbilical Vein Endothelial Cells; Humans; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase Type III; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Processing, Post-Translational; Receptors, Cytoplasmic and Nuclear; RNA Interference; RNA, Messenger; RNA, Small Interfering; Signal Transduction; Soluble Guanylyl Cyclase

Tanshinone IIA extracted from danshen, a popular medicinal herb used in traditional Chinese medicine, exhibits cardio-protective effects. However, the mechanism of its cardioprotective effect is not well established. The aims of this study were to examine whether tanshinone IIA may alter angiotensin II (Ang II)-induced cell proliferation and to identify the putative underlying signaling pathways in rat cardiac fibroblasts. Cultured rat cardiac fibroblasts were pre-treated with tanshinone IIA and stimulated with Ang II, cell proliferation and endothelin-1 (ET-1) expression were examined. The effect of tanshinone IIA on Ang II-induced reactive oxygen species (ROS) formation, and extracellular signal-regulated kinase (ERK) phosphorylation were also examined. In addition, the effect of tanshinone IIA on nitric oxide (NO) production, and endothelial nitric oxide synthase (eNOS) phosphorylation were tested to elucidate the intracellular mechanism. The increased cell proliferation and ET-1 expression by Ang II (100 nM) were partially inhibited by tanshinone IIA. Tanshinone IIA also inhibited Ang II-increased ROS formation, and ERK phosphorylation. In addition, tanshinone IIA was found to increase the NO generation, and eNOS phosphorylation. N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS, and the short interfering RNA transfection for eNOS markedly attenuated the inhibitory effect of tanshinone IIA on Ang II-induced cell proliferation. The results suggest that tanshinone IIA prevents cardiac fibroblast proliferation by interfering with the generation of ROS and involves the activation of the eNOS-NO pathway.

Topics: Abietanes; Angiotensin II; Animals; Antioxidants; Cell Proliferation; Cells, Cultured; Drugs, Chinese Herbal; Endothelin-1; Extracellular Signal-Regulated MAP Kinases; Heart; Myocardium; Myofibroblasts; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase Type III; Phosphorylation; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; RNA, Small Interfering; Salvia miltiorrhiza; Signal Transduction; Transfection

To investigate the effects of tanshinone IIA (Tan IIA) on the regulation of the production of endothelin (ET)-1 (including large ET-1), mRNA levels of ET-1, endothelin-converting enzyme-1 (ECE-1), endothelin-A receptor (ETA) and endothelin-B receptor (ETB) induced by TNF-alpha in rat brain microvascular endothelial cells (BMVEC).. The ET-1 release (including large ET-1) into the culture medium was determined by enzyme immunoassay. The levels of ET-1, ECE-1, ETA, and ETB mRNA were measured by RT-PCR. Endothelin receptor binding was also tested.. The induction of ET-1 release by TNF-alpha from cultured BMVEC was dose-dependently reduced by Tan IIA, but large ET-1 levels progressively increased in response to Tan IIA; the mRNA expression of ET-1 was unaffected. Tan IIA also caused a decrease in ETA receptor mRNA and ECE-1 expression in a dose-dependent manner. Endothelin receptor binding was unaltered in BMVEC stimulated with TNF-alpha alone or a combination of TNF-alpha and Tan IIA.. These findings suggest that Tan IIA may inhibit ET-1 production in TNF-alpha-induced BMVEC through the suppression of ECE-1 synthesis.

Topics: Abietanes; Animals; Aspartic Acid Endopeptidases; Brain; Cell Survival; Cells, Cultured; Endothelial Cells; Endothelin-1; Endothelin-Converting Enzymes; Metalloendopeptidases; Phenanthrenes; Rats; Rats, Wistar; Receptor, Endothelin A; Receptor, Endothelin B; RNA, Messenger; Tumor Necrosis Factor-alpha