PDF(Pubmed)
Abstract：
The complement system plays a critical role in the innate immune response, acting as a first line of defense against invading pathogens. However, dysregulation of the complement system is implicated in the pathogenesis of numerous diseases, ranging from Alzheimer\'s to age-related macular degeneration and rare blood disorders. As such, complement inhibitors have enormous potential to alleviate disease burden. While a few complement inhibitors are in clinical use, there is still a significant unmet medical need for the discovery and development of novel inhibitors to treat patients suffering from disorders of the complement system. A key hurdle in the development of complement inhibitors has been the determination of their mechanism of action. Progression along the complement cascade involves the formation of numerous multimeric protein complexes, creating the potential for inhibitors to act at multiple nodes in the pathway. This is especially true for molecules that target the central component C3 and its fragment C3b, which serve a dual role as a substrate for the C3 convertases and as a scaffolding protein in both the C3 and C5 convertases. Here, we report a step-by-step in vitro reconstitution of the complement alternative pathway using bio-layer interferometry. By physically uncoupling each step in the pathway, we were able to determine the kinetic signature of inhibitors that act at single steps in the pathway and delineate the full mechanism of action of known and novel C3 inhibitors. The method could have utility in drug discovery and further elucidating the biochemistry of the complement system.
摘要：
补体系统在先天性免疫反应中起关键作用，作为抵御入侵病原体的第一道防线。然而,补体系统的失调与许多疾病的发病机理有关，从阿尔茨海默氏症到年龄相关性黄斑变性（AMD）和罕见的血液疾病。因此，补体抑制剂具有减轻疾病负担的巨大潜力。虽然一些补体抑制剂在临床使用，对于发现和开发新的抑制剂来治疗患有补体系统疾病的患者，仍然存在显著的未满足的医学需求。开发补体抑制剂的关键障碍是确定其作用机制。沿着补体级联的进展涉及许多多聚体蛋白复合物的形成，创造了抑制剂在通路中多个节点起作用的潜力。对于靶向中心成分C3及其片段C3b的分子尤其如此，作为C3转化酶的底物和作为C3和C5转化酶中的支架蛋白的双重作用。这里,我们报道了使用生物层干涉法逐步在体外重建补体替代途径。通过物理解耦路径中的每个步骤，我们能够确定在通路中单步起作用的抑制剂的动力学特征,并描述了已知和新型C3抑制剂的全部作用机制.该方法可用于药物发现和进一步阐明补体系统的生物化学。
