An integrated mass spectrometry approach to study heparin structure-bioactivity

项目摘要 肝素可以说是最通用的生物聚合物，能够与细胞相互作用并调节细胞的行为。 令人印象深刻的各种生物分子，甚至在其天然环境（肥大细胞颗粒）之外。很大一部分 肝素相互作用组在人体内的各种生理过程（包括 几种病理学），被认为是高价值的治疗靶点，尽管目前抗凝血酶 仍然是唯一的蛋白质，其相互作用与肝素已被成功地利用在医学上。成功 将肝素独特的多功能性用于其他治疗目的的开发关键取决于 表征其与相关蛋白质的相互作用;然而，具体的分子机制仍然难以捉摸 除了极少数被广泛研究的系统之外。在前期的支持中，我们开发了强大的 能够在整个分子水平上提供蛋白质/肝素相互作用信息的分析工具， 以及鉴定高度异质性肝素大分子内的特定结构基序， 它们与特定蛋白质的结合。在这一成功的基础上，我们现在建议将调查重点放在 了解肝素诱导的血小板减少症（HIT）的分子机制， 严重（和潜在致命）免疫疾病，影响高达5%的接受肝素治疗的患者 抗凝剂尽管肝素在抗原聚集体的形成中发挥了重要作用， HIT的发展，相对知之甚少的具体分子机制，管理这些 交互.这不仅对设计有效的抗HIT的能力提出了巨大的挑战， 治疗策略，而且还阻止了这种病理发生的可靠预后。认识 可能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，PF 4），我们将使用多水平策略来研究PF 4/肝素缔合的机制， 这些聚集体和使它们具有免疫原性并触发HIT发作的特异性特征。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 我博士Nazy是血小板减少症和血栓形成领域的领先专家。这些知识将催化 努力为HIT开发可靠的诊断和预后工具，对于设计安全和 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.