Department of Endocrinology, Jagiellonian University Medical College, Krakow, Poland; University Hospital, Krakow, Poland.
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
Biochem Biophys Res Commun. 2022 Sep 17;621:53-58. doi: 10.1016/j.bbrc.2022.06.063. Epub 2022 Jun 28.
Mechanisms behind disturbed fibrinolysis in pulmonary embolism (PE) are poorly understood. We hypothesized that oxidative stress-induced changes in plasminogen contribute to impaired fibrinolysis in patients with acute PE.
Oxidative and other modifications were investigated using mass-spectrometry in plasminogen purified from pooled plasma of 5 acute PE patients on admission and after 3 months of anticoagulant treatment, along with plasma clot lysis time, a measure of global efficiency of fibrinolysis, and a stable oxidative stress marker, plasma 8-isoprostane.
Twenty sites of oxidation, 3 sites of carbonylation and 4 sites of S-nitrosylation were identified in plasminogen. The intensity of peptides oxidized at cysteine residues with respect to unmodified peptides decreased after 3 months of anticoagulation (p = 0.018). This was not observed for oxidized methionine residues (p = 0.9). Oxidized tryptophan (n = 4) and proline (n = 2), as well as carbonylation at 3 threonine residues were selectively identified in acute PE episode, not after 3 months. This was accompanied by 12.8% decrease in clot lysis time (p = 0.043). Deamidation occurred at the arginine, previously identified to undergo the cleavage by plasminogen activator. Methylated were two lysine-binding sites important for an interaction of plasminogen with fibrin. Other identified modifications involved: glycation, acetylation, phosphorylation, homocysteinylation, carbamylation and dichlorination (88 modifications at 162 sites).
Data suggest that oxidative stress-induced changes in plasminogen molecules may contribute to less effective global fibrinolysis in patients with acute PE. The comprehensive library of posttranslational modifications in plasminogen molecules was provided, including modifications of sites reported to be involved in important biological functions.
肺栓塞（PE）中纤维蛋白溶解紊乱的机制尚不清楚。我们假设氧化应激诱导的纤溶酶原变化导致急性 PE 患者纤维蛋白溶解受损。
使用质谱法研究了从 5 名急性 PE 患者入院时和抗凝治疗 3 个月后混合血浆中纯化的纤溶酶原中的氧化和其他修饰，以及血浆凝块溶解时间，这是衡量纤维蛋白溶解整体效率的指标，以及稳定的氧化应激标志物，血浆 8-异前列腺素。
在纤溶酶原中鉴定出 20 个氧化位点、3 个羰基化位点和 4 个 S-亚硝基化位点。与未修饰肽相比，抗凝治疗 3 个月后，半胱氨酸残基氧化肽的强度降低（p=0.018）。这在氧化蛋氨酸残基时并未观察到（p=0.9）。氧化色氨酸（n=4）和脯氨酸（n=2）以及 3 个苏氨酸残基的羰基化仅在急性 PE 发作时被选择性鉴定，而不是在 3 个月后。这伴随着凝块溶解时间减少 12.8%（p=0.043）。精氨酸发生脱酰胺作用，先前鉴定出该酶可被纤溶酶原激活剂切割。两个赖氨酸结合位点发生甲基化，这对于纤溶酶原与纤维蛋白的相互作用很重要。其他鉴定的修饰包括：糖化、乙酰化、磷酸化、同型半胱氨酸化、氨甲酰化和二氯化（162 个位点的 88 种修饰）。
数据表明，氧化应激诱导的纤溶酶原分子变化可能导致急性 PE 患者的整体纤维蛋白溶解效率降低。提供了纤溶酶原分子中翻译后修饰的综合文库，包括涉及重要生物学功能的位点的修饰。
