Komorowicz Erzsébet, Gurabi Anna, Wacha András, Szabó László, Ozohanics Olivér, Kolev Krasimir
Department of Biochemistry, Semmelweis University, 1085 Budapest, Hungary.
Institute of Materials and Environmental Chemistry, HUN-REN Research Centre for Natural Sciences, 1117 Budapest, Hungary.
Int J Mol Sci. 2025 Jun 17;26(12):5799. doi: 10.3390/ijms26125799.
The fibrin matrix of thrombi is intertwined with neutrophil extracellular traps (NETs) containing histones that render resistance to fibrinolysis. During NET formation, histones are citrullinated. Our study addresses the question of whether citrullination modifies the fibrin-stabilizing effects of histones. We studied the structure and viscoelastic properties of fibrin formed in the presence of native or citrullinated H1 and core histones by scanning electron microscopy, clot permeation, and oscillation rheometry. The kinetics of fibrin formation and its dissolution were followed by turbidimetry and thromboelastometry. Co-polymerizing H1 with fibrin enhanced the mechanical strength of the clots, thickened the fibrin fibers, and enlarged the gel pores. In contrast, the addition of core histones resulted in a reduction in the fiber diameter, and the pores were only slightly larger, whereas the mechanical stability was not modified. Plasmin-mediated fibrinogen degradation was delayed by native and citrullinated core histones, but not by H1, and the action of des-kringle1-4-plasmin was not affected. Plasmin-mediated fibrinolysis was inhibited by native and citrullinated core histones, and this effect was moderated when the kringle domains of plasmin were blocked or deleted. These findings suggest that in NET-containing thrombi that are rich in core histones, alternative fibrinolytic enzymes lacking kringle domains are more efficient lytic agents than the classic plasmin-dependent fibrinolysis.
血栓的纤维蛋白基质与含有组蛋白的中性粒细胞胞外诱捕网（NETs）相互缠绕，这些组蛋白可抵抗纤维蛋白溶解。在NET形成过程中，组蛋白会发生瓜氨酸化。我们的研究探讨了瓜氨酸化是否会改变组蛋白对纤维蛋白的稳定作用。我们通过扫描电子显微镜、凝块渗透和振荡流变学研究了在天然或瓜氨酸化的H1及核心组蛋白存在下形成的纤维蛋白的结构和粘弹性特性。通过比浊法和血栓弹力图法追踪纤维蛋白形成及其溶解的动力学过程。H1与纤维蛋白共聚可增强凝块的机械强度，使纤维蛋白纤维变粗，并扩大凝胶孔隙。相比之下，添加核心组蛋白会导致纤维直径减小，孔隙仅略有增大，而机械稳定性未改变。天然和瓜氨酸化的核心组蛋白可延迟纤溶酶介导的纤维蛋白原降解，但H1不会，并且去-1-4- kringle纤溶酶的作用不受影响。天然和瓜氨酸化的核心组蛋白可抑制纤溶酶介导的纤维蛋白溶解，当纤溶酶的kringle结构域被阻断或缺失时，这种作用会减弱。这些发现表明，在富含核心组蛋白的含NET血栓中，缺乏kringle结构域的替代纤维蛋白溶解酶比经典的纤溶酶依赖性纤维蛋白溶解更有效地发挥溶解作用。
