Protective effects of anti-C5a in sepsis

描述（由申请人提供）：在此完全修订的竞争性更新申请中，我们将继续寻求证据，证明在啮齿动物盲肠结扎和穿刺（CLP）后的实验性脓毒症期间，炎症系统的调节丧失，导致各种有害结果（器官功能障碍、吞噬细胞先天免疫功能丧失和凝血/纤溶系统激活）。这些结果与补体系统的不受控制的激活、C5 a的产生及其与其受体（C5 aR和C5 L2）的相互作用有关。受体参与的平衡决定了不利和致命的结果。在目标1中。我们建议使用C5 a受体KO小鼠来确定CLP后的存活率如何受到影响以及炎症介质的全身水平如何受到影响。在目标2中，我们将继续我们最近的研究，这些研究表明，在脓毒症心脏和心肌细胞（CM）功能障碍可能与CM上C5 a与C5 aR的相互作用，所涉及的信号传导机制以及CM在脓毒症期间产生有害介质的程度有关。在目标3中，我们将寻求C5 a可以在脓毒症期间在体外和体内引起滤过泡形成和C5 aR富集的微粒（MP）脱落的证据，以及CLP后MP的出现是否是C5 a依赖性的，涉及的信号传导机制，以及MP是否代表脓毒症的有用生物标志物。最后，在目标4中，我们将寻求证据表明IL-17的产生是由IL-23驱动的，并在脓毒症期间作为“主开关”发挥作用，以促进有害炎症介质的全身产生。这些研究中的统一主题是脓毒症诱导的C5 a产生，其与其受体相互作用，导致高度破坏性的结果。

DESCRIPTION (provided by applicant): In this completely revised Competiting Renewal Application, we will continue to pursue evidence that, during experimental sepsis after cecal ligation and puncture (CLP) in rodents, regulation of the inflammatory system is lost, resulting in a variety of harmful outcomes (organ dysfunction, loss of innate immune functions of phagocytic cells and activation of the clotting/fibrinolytic system). These outcomes are linked to uncontrolled activation of the complement system, generation of C5a and its interaction with its receptors (C5aR and C5L2). The balance in receptor engagement determines adverse and lethal outcomes. In Aim 1. we propose to use C5a receptor KO mice to determine how survival after CLP is affected and how systemic levels of inflammatory mediators are affected. In Aim 2 we will pursue our recent studies which indicate that in sepsis heart and cardiomyocyte (CM) dysfunction can be linked to interaction of C5a with C5aR on CMs, the signaling mechanisms involved, and the extent to which CMs can produce harmful mediators during sepsis. In Aim 3 we will pursue evidence that C5a can cause bleb formation and shedding of C5aR-enriched microparticles (MPs) in vitro and in vivo during sepsis and whether MP appearance after CLP is C5a dependent, the signaling mechanisms involved, and whether MPs represent a useful biomarker of sepsis. Finally, in Aim 4 we will pursue evidence that IL-17 production is driven by IL-23 and functions as "master switch" during sepsis to promote systemic production of harmful inflammatory mediators. The unifying theme in these studies is sepsis-induced production of C5a which, interacting with its receptors, results in highly destructive outcomes.