An integrated mass spectrometry approach to study heparin structure-bioactivity

项目总结 肝素可以说是用途最广的生物聚合物，能够与人相互作用并调节人的行为 令人印象深刻的各种生物分子，甚至在其自然环境之外(肥大细胞颗粒)。一大部分 在人体内的肝素相互作用体是各种生理过程中的关键角色(包括 几种病理疾病)，被认为是高价值的治疗靶点，尽管目前抗凝血酶 仍然是唯一一种在医学上成功利用与肝素相互作用的蛋白质。成功 将肝素独特的多功能性用于其他治疗目的关键取决于是否有能力 鉴定其与相关蛋白质的相互作用；然而，具体的分子机制仍不清楚 在极少数被广泛研究的系统之外。在之前的支持期间，我们开发了强大的 能够在整个分子水平上提供蛋白质/肝素相互作用的信息的分析工具，如 并在高度不均匀的肝素大分子中识别特定的结构基序，使 它们与特定蛋白质的联系。在这一成功的基础上，我们现在建议将我们的调查重点放在 了解肝素诱导的血小板减少症(HIT)的分子发病机制 严重的(可能致命的)免疫紊乱影响多达5%的接受肝素治疗的患者 抗凝剂。尽管肝素在形成抗原聚集体方面发挥了中心作用，但这可能会导致 对于HIT的发展，人们对其具体的分子机制知之甚少 互动。这不仅对设计有效的反命中能力造成了巨大的挑战 治疗策略，也能防止这种病理发生可靠的预后。认识 调节肝素与相关蛋白(主要是血小板)相互作用的多种因素的重要性 因子4，PF4)，我们将使用多水平策略来研究PF4/肝素结合的机制、结构 这些聚集体和使它们具有免疫原性并触发HIT开始的特定特征。这项工作 将与麦克马斯特大学健康中心的血液学团队密切合作进行 由I·纳西博士撰写，他是血小板减少和血栓形成领域的主要专家。这一知识将催化 努力为HIT开发可靠的诊断和预后工具，并将对设计安全和 有效的治疗干预策略。

PROJECT SUMMARY Heparin is arguably the most versatile biopolymer, capable of interacting with and modulating the behavior of an impressive variety of biomolecules even outside of its native environment (mast cell granules). A large fraction of heparin interactome in the human body are key players in a variety of physiological processes (including several pathologies) and are considered high-value therapeutic targets, although at present antithrombin remains the only protein whose interaction with heparin has been successfully exploited in medicine. Successful exploitation of heparin’s unique versatility for other therapeutic purposes critically depends on the ability to characterize its interactions with relevant proteins; however, specific molecular mechanisms remain elusive outside of the very few extensively studied systems. In the previous period of support, we developed powerful analytical tools capable of providing information on protein/heparin interactions at the whole molecule level, as well as identifying specific structural motifs within highly heterogeneous heparin macromolecules that enable their association with specific proteins. Building upon this success, we now propose to focus our inquiry on understanding the molecular mechanisms underlying etiology of heparin-induced thrombocytopenia (HIT), a serious (and potentially fatal) immune disorder affecting up to 5% of patients receiving heparin as an anticoagulant. Despite the central role played by heparin in formation of antigenic aggregates that may lead to development of HIT, relatively little is known about the specific molecular mechanisms governing these interactions. This not only creates a tremendous challenge vis-a-vis the ability to design efficient anti-HIT therapeutic strategies, but also prevents a reliable prognosis of the occurrence of this pathology. Recognizing the importance of multiple factors that may modulate interaction of heparin with relevant proteins (mostly platelet factor 4, PF4), we will use a multi-level strategy to study the mechanism of PF4/heparin association, architecture of these aggregates and specific features that make them immunogenic and trigger the onset of HIT. The work will be carried out in close collaboration with the Hematology team at McMaster University Health Centre headed by Dr. I. Nazy, a leading expert in the field of thrombocytopenia and thrombosis. This knowledge will catalyze efforts to develop reliable diagnostic and prognostic tools for HIT, and will be critical for designing safe and effective therapeutic intervention strategies.