title: Modulation of plasminogen activator inhibitor-1 (PAI-1) by the naphthoquinone shikonin.
abstract: Plasminogen activator inhibitor-1 (PAI-1) is a key negative regulator of the fibrinolytic system. Elevated levels of PAI-1 are associated with thrombosis and cardiovascular and metabolic diseases. Inhibition of PAI-1 activity represents a new strategy for antithrombotic and antifibrinolysis therapies. In this study, we systematically investigated the inhibitory effect of shikonin on PAI-1 activity. In the chromogenic substrate-based urokinase (uPA)/PAI-1 assay, we found that shikonin inhibited human PAI-1 activity with IC50 values of 30.68±2.32μM. This result was further confirmed by urokinase-type plasminogen activator (uPA)-mediated clot lysis assay. Mechanistic studies indicated that shikonin directly could bind to PAI-1 and prevent the binding of PAI-1 to uPA in a dose-dependent manner. Shikonin also blocked the formation of PAI-1/uPA complex, as shown by SDS/PAGE analysis. In the mouse arterial thrombosis model, intraperitoneal injection of shikonin at 1mgkg(-1) dose significantly prolonged tail bleeding time from 12.956±4.457min to 26.576±2.443min. It also reduced arterial thrombus weight from 0.01±0.001g to 0.006±0.001g (p<0.05). In a liver fibrosis treatment model, when shikonin was continuously injected intraperitoneally at a dose of 1mgkg(-1) over a two-week period, the hydroxyproline content in the mice plasma was significantly reduced and the degree of liver fibrosis was decreased significantly. Thus, shikonin may represent a novel small molecule inhibitor of PAI-1 that could have become a lead drug the treatment of thrombus and fibrosis.
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, PR China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Han
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, PR China.
authors.forename: Guangping
authors.initials: G
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian 116029, PR China.
authors.forename: Dong
authors.initials: D
authors.lastname: Yan
authors.affiliation: School of Life Sciences, Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian 116029, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.affiliation: School of Life Sciences, Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian 116029, PR China.
authors.forename: Tonghui
authors.initials: T
authors.lastname: Ma
authors.affiliation: Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, PR China. Electronic address: zuguangye@icmm.ac.cn.
authors.forename: Zuguang
authors.initials: Z
authors.lastname: Ye
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006801:Humans; D008103:Liver Cirrhosis / Q000188:drug therapy; D051379:Mice; D009285:Naphthoquinones / Q000494:pharmacology*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D013927:Thrombosis / Q000188:drug therapy*; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
chemical_list: D009285:Naphthoquinones; D017395:Plasminogen Activator Inhibitor 1; C051321:SERPINE1 protein, human; C016101:shikonin; D014568:Urokinase-Type Plasminogen Activator
keywords: Fibrinolysis; PAI-1; PAI-1 inhibitor; Pharmacology; Thrombolysis