title: Mechanical stability and fibrinolytic resistance of clots containing fibrin, DNA, and histones.
abstract: Neutrophil extracellular traps are networks of DNA and associated proteins produced by nucleosome release from activated neutrophils in response to infection stimuli and have recently been identified as key mediators between innate immunity, inflammation, and hemostasis. The interaction of DNA and histones with a number of hemostatic factors has been shown to promote clotting and is associated with increased thrombosis, but little is known about the effects of DNA and histones on the regulation of fibrin stability and fibrinolysis. Here we demonstrate that the addition of histone-DNA complexes to fibrin results in thicker fibers (increase in median diameter from 84 to 123 nm according to scanning electron microscopy data) accompanied by improved stability and rigidity (the critical shear stress causing loss of fibrin viscosity increases from 150 to 376 Pa whereas the storage modulus of the gel increases from 62 to 82 pascals according to oscillation rheometric data). The effects of DNA and histones alone are subtle and suggest that histones affect clot structure whereas DNA changes the way clots are lysed. The combination of histones + DNA significantly prolongs clot lysis. Isothermal titration and confocal microscopy studies suggest that histones and DNA bind large fibrin degradation products with 191 and 136 nM dissociation constants, respectively, interactions that inhibit clot lysis. Heparin, which is known to interfere with the formation of neutrophil extracellular traps, appears to prolong lysis time at a concentration favoring ternary histone-DNA-heparin complex formation, and DNase effectively promotes clot lysis in combination with tissue plasminogen activator.
authors.affiliation: Biotherapeutics, Haemostasis Section, National Institute for Biological Standards and Control, South Mimms, Potters Bar EN6 3QG, United Kingdom. colin.longstaff@nibsc.hpa.org.uk
authors.forename: Colin
authors.initials: C
authors.lastname: Longstaff
authors.forename: Imre
authors.initials: I
authors.lastname: Varjú
authors.forename: Péter
authors.initials: P
authors.lastname: Sótonyi
authors.forename: László
authors.initials: L
authors.lastname: Szabó
authors.forename: Michael
authors.initials: M
authors.lastname: Krumrey
authors.forename: Armin
authors.initials: A
authors.lastname: Hoell
authors.forename: Attila
authors.initials: A
authors.lastname: Bóta
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Varga
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Komorowicz
authors.forename: Krasimir
authors.initials: K
authors.lastname: Kolev
mesh_terms: D000925:Anticoagulants / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001777:Blood Coagulation; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism; D005337:Fibrin / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D005342:Fibrinolysis / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006493:Heparin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006657:Histones / Q000737:chemistry* / Q000378:metabolism; D046911:Macromolecular Substances / Q000737:chemistry / Q000378:metabolism; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009504:Neutrophils / Q000378:metabolism; D055550:Protein Stability / Q000187:drug effects; D053838:Scattering, Small Angle; D013314:Stress, Mechanical; D013927:Thrombosis / Q000097:blood / Q000378:metabolism; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D000925:Anticoagulants; D006657:Histones; D046911:Macromolecular Substances; D049452:Green Fluorescent Proteins; D005337:Fibrin; D006493:Heparin; D004247:DNA; D003851:Deoxyribonucleases; D010959:Tissue Plasminogen Activator