Effects of Sleep Deprivation on Infection Induced Organ Failure

描述(申请人提供)：最近的研究表明，危重病患者睡眠不佳，经常受到干扰，失去昼夜节律，在恢复期的睡眠时间百分比显著减少。重要的是，这些患者的睡眠不足可能会产生不良后果。与这一概念一致，最近的两项动物研究发现，睡眠剥夺显著增加了脓毒症的死亡率，但导致这种现象的机制完全不清楚。我们将测试特定的假设，即睡眠剥夺与感染相互作用激活内质网(ER)应激途径，以及ER应激途径的激活反过来导致多个器官衰竭。目的1确定感染和睡眠剥夺是否在多个组织中协同诱导内质网应激，以及内质网应激途径激活是否导致器官衰竭。研究将使用脓毒症(盲肠结扎和穿孔，CLP)和睡眠剥夺(SD)的动物模型进行。实验1.1将检验这一假设，即脓毒症和睡眠剥夺相互作用，诱导内质网应激，内质网应激途径与器官衰竭的发展平行激活。实验1.2将检验这样一种假设，即内质网应激的化学激活会触发病理变化(例如，下游蛋白分解通路的激活)，从而导致器官功能障碍。目的2阐明脓毒症和睡眠剥夺激活内质网应激途径的上游机制。实验2.1将验证这一假设，即细胞因子诱导的活性氧物种(ROS)的产生是激活脓毒症内质网应激的关键上游触发因素。实验2.2将验证这一假说，即外周组织时钟基因功能的上游变化激活了内质网应激途径，以回应睡眠剥夺。实验2.3将验证这一假说，即外周组织时钟功能的破坏增加了ROS的产生，并激活了内质网应激途径。目的3将确定给予内质网应激途径的药物抑制剂是否能改善脓毒症和睡眠剥夺时的器官功能。实验3.1、3.2和3.3将检验以下假设： Caspase12抑制剂atad-fmk、eIF2去磷酸化选择性抑制剂salubrine或抑制IRE1途径的内源性激素褪黑素可阻断内质网应激途径依赖性的细胞损伤，改善CLP+SD的器官功能。实验3.4将验证延迟给药的假说，以发现产生最佳治疗效果的药物将阻断ER应激途径依赖的细胞损伤，并改善CLP+SD的器官功能。

DESCRIPTION (provided by applicant): Recent studies indicate that critically ill patients experience poor sleep, frequent disruptions, loss of circadian rhythm and a marked reduction of the percentage of sleep time spent in restorative stages. Importantly, sleep deprivation in these patients may have adverse consequences. In keeping with this concept, two recent animal studies found that sleep deprivation markedly increases death in sepsis, but the mechanisms responsible for this phenomenon are completely unknown. We will test the specific hypotheses that sleep deprivation interacts with infection to activate endoplasmic reticulum (ER) stress pathways and that ER stress pathway activation, in turn, causes failure of multiple organs. Aim 1 will determine if infection and sleep deprivation synergistically induce ER stress in multiple tissues and if ER stress pathway activation produces organ failure. Studies will be performed using animal models of sepsis (cecal ligation and puncture, CLP) and sleep deprivation (SD). Experiment 1.1 will test the hypothesis that sepsis and sleep deprivation interact to induce ER stress, with ER stress pathways activated in parallel with development of organ failure. Experiment 1.2 will test the hypothesis that chemical activation of ER stress triggers pathological alterations (e.g. activation of downstream proteolytic pathways) that produce organ dysfunction. Aim 2 will elucidate the upstream mechanisms by which sepsis and sleep deprivation activate ER stress pathways. Experiment 2.1 will test the hypothesis that cytokine-induced production of reactive oxygen species (ROS) is the key upstream trigger that activates ER stress in sepsis. Experiment 2.2 will test the hypothesis that upstream alterations in peripheral tissue clock gene function activate ER stress pathways in response to sleep deprivation. Experiment 2.3 will test the hypothesis that disruption of peripheral tissue clock function increases ROS generation, and activates ER stress pathways. Aim 3 will determine if administration of pharmacological inhibitors of ER stress pathways improves organ function in sepsis and sleep deprivation. Experiments 3.1, 3.2, and 3.3 will test the hypothesis that either z- ATAD-fmk (a caspase 12 inhibitor), salubrinal (a selective inhibitor of eIF2¿ dephosphorylation), or melatonin (an endogenous hormone that inhibits the IRE1¿ pathway) will block ER stress pathway dependent cell damage and improve organ function in CLP+SD. Experiment 3.4 will test the hypothesis that delayed administration of the pharmacologic agent to found to produce the best therapeutic effect will block ER stress pathway dependent cell damage and improve organ function in CLP+SD.