Characterization of the molecular basis of labile heme as a prothrombotic modulator under hemolytic conditions

溶血条件下不稳定血红素作为血栓前调节剂的分子基础表征

• 批准号: 507218303
• 负责人: Professorin Dr. Marie-Therese Hopp
• 金额: --
• 依托单位: Abteilung Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/507218303?language=en
• 关键词: Characterization; molecular; basis; labile; heme

The metalloporphyrin heme is a coordination complex of an iron ion incorporated in a porphyrin ring system, which is widely distributed in the body as an essential part of hemoproteins, especially the oxygen-transport protein hemoglobin. An unbalanced heme homeostasis leads to the release of heme, whose clearance is usually regulated by several proteins including hemopexin. Increased intravascular heme levels, however, have been associated with prothrombotic, cytotoxic, proinflammatory, and complement-activating effects, which characterize the harmful complications observed in patients suffering from hemolytic disorders, such as sickle cell disease and transfusion-related hemolysis. Considering the high prevalence of thrombosis and the associated mortality it is surprising that the mechanistic link between labile heme and prothrombotic effects is not yet completely elucidated on the molecular level. Concerning the most relevant proteins in this context, namely the components of the blood coagulation system, distinct proteins, among them factor VIII, activated protein C, and fibrinogen, have been identified as heme-binding or even heme-regulated proteins, while others (thrombin, FXIIIa) do not bind heme. Many questions regarding a potential interaction of heme with most of the coagulation factors are still open. This proposal thus aims at the elucidation of the transient interaction of heme with the coagulation factor FVIII and von Willebrand factor by means of biophysical (e.g., UV/Vis, SPR) and structural analysis (rRaman) methods. In addition, biochemical and hematological functional assays as well as cellular approaches with high physiological relevance (e.g., platelet/endothelial cell function analysis) will be performed. The results obtained will be incorporated into the mechanistic knowledge graph HemeKG to crosslink the already known effects and to unravel so far unknown aspects of heme’s coagulation-modulating effects. In conclusion, the procoagulant effects of heme will be targeted on different levels, i.e. the molecular, biochemical, bioinformatic, and cellular level applying a variety of spectroscopic methods and functional assays. This will allow for a more detailed characterization of heme’s prothrombotic nature and provide new perspectives for the treatment of hemolysis-associated thrombosis.

金属卟啉血红素是铁离子结合在卟啉环系统中的配位络合物，其作为血红素蛋白，特别是氧转运蛋白血红蛋白的必需部分广泛分布于体内。血红素稳态失衡导致血红素释放，血红素的清除通常由包括血红素结合蛋白在内的几种蛋白质调节。然而，增加的血管内血红素水平与促血栓形成、细胞毒性、促炎和补体激活作用相关，其表征了在患有溶血性疾病（例如镰状细胞病和输血相关溶血）的患者中观察到的有害并发症。考虑到血栓形成的高患病率和相关的死亡率，令人惊讶的是，不稳定血红素和促血栓形成作用之间的机制联系尚未在分子水平上完全阐明。关于在这种情况下最相关的蛋白质，即血液凝固系统的组分，不同的蛋白质，其中因子VIII、活化蛋白C和纤维蛋白原，已被鉴定为血红素结合蛋白或甚至血红素调节蛋白，而其他蛋白质（凝血酶，FXIIIa）不结合血红素。关于血红素与大多数凝血因子的潜在相互作用的许多问题仍然是开放的。因此，该提议旨在通过生物物理学（例如，UV/维斯，SPR）和结构分析（拉曼）方法。此外，生物化学和血液学功能测定以及具有高生理相关性的细胞方法（例如，血小板/内皮细胞功能分析）。所获得的结果将被纳入机制知识图HemeKG交联已知的影响，并解开血红素的凝血调节作用迄今未知的方面。总之，血红素的促凝血作用将在不同水平上，即分子、生物化学、生物信息学和细胞水平上应用各种光谱方法和功能测定来靶向。这将允许更详细的表征血红素的促血栓形成的性质，并提供新的观点溶血相关的血栓形成的治疗。