title: Effects of extracellular DNA on plasminogen activation and fibrinolysis.
abstract: The increased levels of extracellular DNA found in a number of disorders involving dysregulation of the fibrinolytic system may affect interactions between fibrinolytic enzymes and inhibitors. Double-stranded (ds) DNA and oligonucleotides bind tissue-(tPA) and urokinase (uPA)-type plasminogen activators, plasmin, and plasminogen with submicromolar affinity. The binding of enzymes to DNA was detected by EMSA, steady-state, and stopped-flow fluorimetry. The interaction of dsDNA/oligonucleotides with tPA and uPA includes a fast bimolecular step, followed by two monomolecular steps, likely indicating slow conformational changes in the enzyme. DNA (0.1-5.0 μg/ml), but not RNA, potentiates the activation of Glu- and Lys-plasminogen by tPA and uPA by 480- and 70-fold and 10.7- and 17-fold, respectively, via a template mechanism similar to that known for fibrin. However, unlike fibrin, dsDNA/oligonucleotides moderately affect the reaction between plasmin and α(2)-antiplasmin and accelerate the inactivation of tPA and two chain uPA by plasminogen activator inhibitor-1 (PAI-1), which is potentiated by vitronectin. dsDNA (0.1-1.0 μg/ml) does not affect the rate of fibrinolysis by plasmin but increases by 4-5-fold the rate of fibrinolysis by Glu-plasminogen/plasminogen activator. The presence of α(2)-antiplasmin abolishes the potentiation of fibrinolysis by dsDNA. At higher concentrations (1.0-20 μg/ml), dsDNA competes for plasmin with fibrin and decreases the rate of fibrinolysis. dsDNA/oligonucleotides incorporated into a fibrin film also inhibit fibrinolysis. Thus, extracellular DNA at physiological concentrations may potentiate fibrinolysis by stimulating fibrin-independent plasminogen activation. Conversely, DNA could inhibit fibrinolysis by increasing the susceptibility of fibrinolytic enzymes to serpins.
authors: Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas 75708-3154. Electronic address: andrey.komissarov@uthct.edu.
authors: Andrey A
authors: AA
authors: Komissarov
authors: Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas 75708-3154.
authors: Galina
authors: G
authors: Florova
authors: Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas 75708-3154.
authors: Steven
authors: S
authors: Idell
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D005342:Fibrinolysis; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances / Q000378:metabolism; D008956:Models, Chemical; D009696:Nucleic Acids / Q000737:chemistry; D009841:Oligonucleotides / Q000737:chemistry; D010958:Plasminogen / Q000378:metabolism*; D010960:Plasminogen Activators / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D012474:Salmon / Q000378:metabolism; D015843:Serpins / Q000378:metabolism; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000737:chemistry; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry
chemical_list: D046911:Macromolecular Substances; D009696:Nucleic Acids; D009841:Oligonucleotides; D011994:Recombinant Proteins; D015843:Serpins; D010958:Plasminogen; D004247:DNA; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator