Protective Effects of Anti-C5a in Sepsis

描述(申请人提供)：我们将继续我们的研究，以确定与盲肠结扎和穿孔(CLP)后啮齿动物感染性心肌病发展相关的分子机制，重点是C5a过敏毒素及其受体C5aR和C5L2的作用。目的1明确C3、C5、C5a受体(C5aR、C5L2)和IL-17对心肌细胞自发释放心脏抑制细胞因子(IL-12、TNF1、IL-6)的要求。这些数据将与CLP小鼠心脏匀浆和血浆中细胞因子的存在进行比较。目的2将确定CLP后C5a受体和CMS上心脏抑制细胞因子(IL-12、TNF1和IL-6)上调的时间进程。目的3研究CLP后CMS的电生理反应(动作电位、钙瞬变、K+和钙电流)和功能反应(通过测量细胞内钙瞬变和心肌细胞收缩)随时间的变化。此外，将研究SHAM和CLP CMS在体外暴露于C5a后电生理和收缩反应的变化，以努力确定C5a导致CMS收缩功能障碍的分子机制。目的4将使用加入了不同浓度的C5a或心脏抑制细胞因子或两者的假C5a和CLP CMS，评估C5a诱导CMS变化的能力(如Aim 3中所述)。我们将确定C5a和心脏抑制细胞因子在电生理功能障碍的发展中是否存在协同作用。AIM 5将使用非侵入性超声心动图方法评估CLP小鼠的收缩和舒张期功能以及全身血管阻力，以及与假手术小鼠相比的其他参数。我们将尝试确定C3、C5、C5a和IL-17受体在CM功能障碍中的作用。这些研究还将以接受过C5a或IL-17中和抗体治疗的CLP小鼠为特色。还将利用C5aR基因敲除小鼠模型来确定C5a信号通路在感染性心肌病发病机制中的作用。总的来说，这些研究应该确定C5a及其受体以及心脏抑制细胞因子在感染性心肌病发展中的作用，以及如何避免或治疗这种并发症。

DESCRIPTION (provided by applicant): We will continue our studies to define molecular mechanisms related to development of septic cardiomyopathy in rodents after cecal ligation and puncture (CLP), with an emphasis on the roles of C5a anaphylatoxin and its receptors, C5aR and C5L2. Aim 1 will define the requirements for C3, C5, C5a receptors (C5aR, C5L2) and IL-17 for spontaneous release of cardiosuppressive cytokines (IL-12, TNF1, IL-6) from sham and CLP cardiomyocytes (CMs). These data will be compared to the presence of cytokines in heart homogenates and plasma from CLP mice. Aim 2 will determine the time course after CLP for upregulation of receptors for C5a and the cardiosuppressive cytokines (IL-12, TNF1 and IL-6) on CMs. Aim 3 will assess electrophysiological responses (action potentials, Ca2+ transients, and K+ and Ca2+ currents) as well as functional responses (by measuring intracellular calcium transients and myocyte contraction) in CMs obtained from sham and CLP rodents as a function of time after CLP. In addition, sham and CLP CMs will be studied for changes in electrophysiological and contractile responses after in vitro exposure to C5a in an effort to define molecular mechanisms by which C5a causes contractile dysfunction in CMs. Aim 4 will assess the ability of C5a to induce changes in CMs (as described in Aim 3), using sham and CLP CMs to which varying concentrations of C5a or cardiosuppressive cytokines, or both, have been added. We will determine if there is a synergy in development of electrophysiological dysfunction with combination of C5a and cardiosuppressive cytokines. Aim 5 will employ non-invasive echocardiography approaches to assess systolic and diastolic function and systemic vascular resistance, as well as other parameters, in CLP mice as compared to sham mice. We will attempt to define the roles of C3, C5, C5a and IL-17 receptors in CM dysfunction. These studies will also feature CLP mice that have been treated with neutralizing antibodies to C5a or IL-17. A C5aR knockout mouse model will also be utilized to define the role of the C5a signaling pathways in the pathogenesis of septic cardiomyopathy. Collectively, these studies should define the roles of C5a and its receptors as well as cardiosuppressive cytokines in the development of septic cardiomyopathy and how this complication can be averted or treated.