Dual role of complement in post-ischemic inflammation and recovery

描述(申请人提供)：缺血/再灌注损伤(IRI)是一种主要的临床问题，与几种临床情况(如失血性休克、严重烧伤、脓毒症、心肌梗死、中风、移植功能障碍/排斥)有关。补体在缺血再灌流(IR)后的无菌炎症和损伤中起关键作用，但近来研究表明，补体在某些缺血事件后的组织修复和再生中也起着重要作用。这些研究的目的是为了更好地了解IR后补体激活事件，并剖析补体效应机制在IRI和组织修复/再生中的双重作用。在这些目标的同时，有人建议开发和表征一种新的靶向补体抑制策略，该策略在促进组织修复和再生的同时防止炎症和损伤。以往和初步的数据表明，补体激活和效应机制相似，参与了多个器官和组织的损伤和修复/再生过程。然而，我们的模型将是肝脏IRI和再生，因为小鼠的模型已经很好地表征了，并且因为临床意义。总体的工作假设是补体是由天然的自身反应性IgM激活的，它与缺血后暴露的新表位结合，终末膜攻击复合体(MAC)在缺血再灌注损伤(IRI)中起关键作用，而更近端的激活产物对修复和再生具有重要作用。我们已经分离了一组新的自身反应性IgM单抗，并将使用这些单抗来研究免疫变化(新表位暴露)和IR或部分肝切除后发生的补体激活事件。我们还将利用在级联中不同点起作用的补体抑制剂来研究涉及炎症、损伤和再生的补体效应器机制。我们还将研究补体在吞噬细胞清除凋亡和坏死细胞中的作用，以及这一过程如何影响炎症环境和随后的组织损伤和修复。最后，我们将通过对临床标本的分析，研究在我们的小鼠模型中产生的数据与人类之间的关系。这些研究的另一个目标是开发一种新的目标策略来 利用单链抗体将补体抑制剂局部输送到缺血后新表位。

DESCRIPTION (provided by applicant): Ischemia/reperfusion injury (IRI) is a major clinical problem associated with several clinical conditions (e.g., hemorrhagic shock, severe burns, sepsis, myocardial infarction, stroke, transplant dysfunction/rejection). Complement is known to play a key role in sterile inflammation and injury following ischemia and reperfusion (IR), but more recently it has become evident that complement also plays important roles in tissue repair and regeneration following certain ischemic events. A goal of the proposed studies is to better understand the complement activation event following IR, and to dissect the dual role of complement effector mechanisms in IRI and tissue repair/regeneration. Concurrent with these goals, it is proposed to develop and characterize a novel targeted complement inhibitory strategy that protects against inflammation and injury while promoting tissue repair and regeneration. Previous and preliminary data indicate similar complement activation and effector mechanisms are involved in the injury and repair/regeneration processes of multiple organs and tissues. However, our model will be hepatic IRI and regeneration since mouse models have been well characterized and because of clinical significance. The overall working hypothesis is that complement is activated by natural self-reactive IgM that binds to neoepitopes exposed after ischemia, and that the terminal membrane attack complex (MAC) plays a key role in ischemia reperfusion injury (IRI) whereas more proximal activation products are important for repair and regeneration. We have isolated a panel of novel self-reactive IgM mAbs, and will use these mAbs to investigate immunological changes (neoepitope exposure) and the complement activation event that occurs after either IR or partial hepatectomy. We will also utilize complement inhibitors that function at different points in the cascade to investigate complement effector mechanisms involved in inflammation, injury and regeneration. We will also investigate the role of complement in phagocytic clearance of apoptotic and necrotic cells, and how this process impacts the inflammatory environment and subsequent tissue injury and repair. Finally, we will investigate how data generated in our mouse models relates to humans by analysis of clinical specimens. An additional goal of these studies is to develop a novel targeting strategy to locally deliver a complement inhibitor to post-ischemic neoepitopes utilizing single chain antibodies.