Extracellular histones promote fibrinolysis by single-chain urokinase-type plasminogen activator in a factor seven activating protease-dependent way. Issue 196 (December 2020)

• Record Type: Journal Article
• Authors: Semeraro, Fabrizio; Ammollo, Concetta T.; Semeraro, Nicola; Colucci, Mario
• Is Part Of: Thrombosis research. Issue 196(2020)
• Page Start: 193
• Page End: 199
• Publication Date: 2020-12
• Subjects: ANOVA analysis of variance -- APC activated protein C -- FSAP factor seven activating protease -- FU fluorescence units -- HBS hepes buffered saline -- NETs neutrophil extracellular traps -- OD optical density -- p-EPR-MNA Pyro-Glu-Pro-Arg-methoxynitroanilide -- scu-PA single chain urokinase-type plasminogen activator -- SEM standard error of the mean -- TF tissue factor -- t-PA tissue plasminogen activator -- UFH unfractionated heparin -- u-PA urokinase-type plasminogen activator -- Z-GGR-AMC Z-Gly-Gly-Arg-7-amino-4-methylcoumarin; Histones -- Plasminogen activators -- Fibrinolysis -- Proteolysis -- FSAP; Thrombosis -- Periodicals; 616.135
• DOI: 10.1016/j.thromres.2020.08.034
• Languages: English
• ISSNs: 0049-3848

Abstract

Abstract: Introduction: Extracellular histones inhibit tissue plasminogen activator (t-PA)-mediated fibrinolysis by modifying fibrin structure and rheological properties. However, other plasminogen activators involved in intravascular and extravascular fibrinolysis have not been considered yet. Objectives: We investigated the effect of histones on fibrinolysis driven by different plasminogen activators. Methods: Clot lysis induced by t-PA, urokinase (u-PA) and its single chain precursor (scu-PA) was evaluated by turbidimetry. Conversion of scu-PA to u-PA and activation of factor seven activating protease (FSAP) were assessed by fluorogenic and chromogenic assays, respectively. Results: Histones delayed t-PA- and u-PA-mediated fibrinolysis but strongly accelerated scu-PA-driven clot lysis through the enhancement of scu-PA to u-PA conversion. This effect required a plasma factor identified as FSAP by the following findings: 1) histones enhanced neither scu-PA activation nor scu-PA-mediated clot lysis under purified conditions; 2) in plasma, the enhancement of fibrinolytic activity by histones was abolished by a neutralizing anti-FSAP antibody; and 3) histones promoted the activation of plasma FSAP. The effect of the natural mixture of histones on scu-PA-driven fibrinolysis was differentially recapitulated by the individual recombinant histones, H4 displaying the strongest activity. When complexed to DNA, histones still accelerated scu-PA-mediated fibrinolysis but with a lesser efficiency due to a reduced FSAP activation. Finally, preincubation of histones with heparin or activated protein C, two known inhibitors of histones, further amplified histone-mediated boost of scu-PA-driven fibrinolysis. Conclusions: Enhancement of FSAP-mediated scu-PA activity by histones may play yet unforeseen roles in intravascular fibrinolysis and contribute to extravascular proteolysis and tissue damage. Highlights: Histones have been reported to inhibit t-PA-induced fibrinolysis. At variance, we show that histones stimulate scu-PA-driven fibrinolysis. Histones promote FSAP activation, which then converts scu-PA to fully active u-PA. Histones may play variable roles in intra- and extra-vascular fibrin(proteo)lysis.