Myeloperoxidase has no effect on the low procoagulant activity of silica-free DNA. Issue 203 (July 2021)

• Record Type: Journal Article
• Authors: Beckmann, Lennart; Voigtlaender, Minna; Rolling, Christina C.; Schulenkorf, Anita; Bokemeyer, Carsten; Langer, Florian
• Is Part Of: Thrombosis research. Issue 203(2021)
• Page Start: 36
• Page End: 45
• Publication Date: 2021-07
• Subjects: cfDNA cell-free DNA -- Cl− chloride -- CTI corn trypsin inhibitor -- DNase I deoxyribonuclease I -- ETP endogenous thrombin potential -- FITC fluorescein isothiocyanate -- FXII factor XII -- FXII-def factor XII deficient -- Gla domain gamma-carboxyglutamic acid-rich domain -- HMWK high-molecular-weight kininogen -- HOCl hypochlorous acid -- H2O2 hydrogen peroxide -- IL-8 interleukin-8 -- LMWH low-molecular-weight heparin -- MPO myeloperoxidase -- MV microvesicle -- NET neutrophil extracellular trap -- NHP normal human plasma -- PaxDNA DNA purified with the PAXgene™ Blood DNA Kit -- PC phosphatidylcholine -- PCA procoagulant activity -- PE phosphatidylethanolamine -- PI phosphatidylinositol -- PKa actived plasma kallikrein -- PL phospholipid -- PLFP phospholipid-free plasma (plasma depleted of its endogenous procoagulant phospholipids) -- PMA phorbol 12-myristate 13-acetate -- PMN polymorphonuclear leukocyte -- PPP platelet-poor plasma -- PS phosphatidylserine -- SD standard deviation -- TF tissue factor -- TFPI tissue factor pathway inhibitor -- TGA thrombin generation assay -- TNFα tumor necrosis factor α; Myeloperoxidase -- Coagulation -- DNA -- Contact pathway -- Neutrophil extracellular traps; Thrombosis -- Periodicals; 616.135
• DOI: 10.1016/j.thromres.2021.04.007
• Languages: English
• ISSNs: 0049-3848

Abstract

Abstract: Blood coagulation and innate immunity are closely interrelated. At sites of inflammation, DNA and myeloperoxidase (MPO) are released from polymorphonuclear leukocytes (PMNs) as an integral component of neutrophil extracellular traps (NETs). NETs exert pleiotropic thrombogenic effects, with DNA-mediated contact activation of factor XII (FXII) likely playing a role. We have previously shown that MPO, a highly cationic protein, regulates coagulation through heteromolecular interactions with various negatively charged structures, including membrane phospholipids and low-molecular-weight heparin. The aims of our current study were to confirm that DNA activates coagulation and to investigate whether its procoagulant activity (PCA) is regulated by PMN-derived MPO. To this end, we used thrombin generation and FXIIa amidolytic activity assays to analyze the PCA of cell-free DNA isolated with silica membrane-based (cfDNA) or silica-free procedures (PaxDNA). cfDNA potently activated FXII and promoted thrombin generation in a concentration-dependent manner, but its PCA was largely attributable to contaminating silica particles. In contrast, pure, i.e. silica-free, PaxDNA was markedly less procoagulant. Although PaxDNA amplified thrombin generation in plasma, it was devoid of any direct FXII activating activity. MPO supershifted both cfDNA and PaxDNA in gel electrophoresis, but only silica-associated PCA of cfDNA was neutralized by MPO independently of its catalytic properties. Moreover, pretreatment with DNase I abolished silica-induced thrombin generation. In summary, we show that pure DNA has rather weak PCA, which is not further inhibited by heteromolecular complex formation with exogenous MPO. Our study thus provides novel mechanistic insights into the regulation of coagulation by extracellular DNA under inflammatory conditions. Highlights: Extracellular MPO regulates coagulation and is released in close proximity to DNA. Pure genomic DNA is a weak initiator of contact-dependent coagulation. Contaminating silica particles can contribute to DNA procoagulant activity (PCA). DNase I may inhibit silica-induced coagulation. MPO neutralizes the PCA of silica particles, but not of DNA.