Mechanism of reversal of high glucose-induced endothelial nitric oxide synthase uncoupling by tanshinone IIA in human endothelial cell line EA.hy926.
Endothelial nitric oxide synthase (eNOS) uncoupling plays a causal role in endothelial dysfunction in many cardiovascular and metabolic diseases. Tanshinone IIA (Tan IIA), an active compound from Salvia miltiorrhiza, has been used to treat cardiovascular and metabolic diseases. However, the effects of Tan IIA on eNOS uncoupling have not been reported. We hypothesize that Tan IIA can regulate eNOS uncoupling in endothelium cells under oxidative stress. The results showed that eNOS-mediated NO generation was significantly decreased, accompanied by increased superoxide production and NOX4 expression. The ratio of eNOS dimer to monomer and NOS cofactor tetrahydrobiopterin (BH4) to 7,8-dihydrobiopterin (BH2) as well as expressions of heat-shock protein of 90kDa (HSP90), GTP cyclohydrolase-1 (GTPCH1) and dihydrofolate reductase (DHFR) were significantly decreased. Tan IIA significantly inhibited superoxide production and expression of NOX4, and increased NO generation and eNOS homodimerization, as well as expressions of HSP90, GTPCH1 and DHFR in a concentration-dependent manner. The ratio of BH4 to BH2 was also elevated by Tan IIA. In addition, Tan IIA significantly inhibited the increase in expression of PI3K in high glucose treated cells. Wortmannin, a PI3K inhibitor, significantly inhibited the high glucose induced NOX4 expression. The results demonstrated that Tan IIA restored eNOS uncoupling induced by high glucose by targeting NADPH oxidase, HSP90, GTPCH1 and DHFR, and PI3K pathway, which leads to reduced intracellular oxidative stress and increased NO generation. Tan IIA may be used as a prototype agent to restore eNOS coupling under certain cardiovascular and metabolic diseases.
Traditional & Complementary Medicine Program, RMIT Health Innovations Research Institute, School of Health Sciences, RMIT University, Bundoora, VIC 3083, Australia.
Zhi-Wei
ZW
Zhou
Xiao-Liang
XL
Xie
Shu-Feng
SF
Zhou
Chun Guang
CG
Li
D045784:Abietanes / Q000494:pharmacology*; D001708:Biopterins / Q000031:analogs & derivatives / Q000378:metabolism; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D006136:GTP Cyclohydrolase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D055503:Protein Multimerization; D015398:Signal Transduction / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism; D015854:Up-Regulation
D045784:Abietanes; D018841:HSP90 Heat-Shock Proteins; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; C021751:tanshinone; D013481:Superoxides; D001708:Biopterins; D009569:Nitric Oxide; C017226:7,8-dihydrobiopterin; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D013762:Tetrahydrofolate Dehydrogenase; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; D058539:Phosphatidylinositol 3-Kinase; D006136:GTP Cyclohydrolase; C003402:sapropterin; D005947:Glucose