Molecular Biology of Hemorrhagic Shock

创伤是这个国家54岁以下人群的主要死亡原因。除了严重的头部损伤外，出血/组织创伤及其后果是这些通常年轻、健康个体发病和死亡的最重要原因。该中心的资助计划旨在促进我们对创伤和出血后导致器官损伤和功能障碍的分子机制的理解。我们的重点是导致炎症反应的激活和传播的事件，认为炎症反应的程度是损伤后早期器官损伤/功能障碍和迟发性免疫功能障碍的主要决定因素。因此，了解激发事件可能会导致有效的方法，以限制不仅是早期器官损伤，但也晚败血症和多器官功能衰竭（MOF）的易感性。 我们认为，理解失血性休克引起的器官损伤的关键之一是表征创伤事件后导致炎症变化的起始和传播的最早分子事件。从以前的资助周期中，我们知道炎症和应激信号的启动在休克诱导后很快发生，并且这些反应的放大涉及一系列重叠事件。我们最近的努力，以确定近端步骤提供了令人信服的证据表明，模式识别受体（PRR）的先天免疫系统（Toll样受体）参与损伤后早期启动和驱动炎症反应。TLR 4和TLR 9是激活炎症信号传导所必需的，而TLR 2和TLR 4明显不受调节，如果被微生物配体触发，则可以诱导过度的炎症反应。来自我们PI的数据表明TLR 2和TLR 9的组织特异性表达和功能模式。TLR信号传导的内源性激活剂称为损伤相关分子模式（DAMP）分子，似乎驱动TLR 4和TLR 9的初始激活。核蛋白高迁移率族蛋白1（HMGB 1）显然参与了这一过程，并在我们的创伤模型中作为原型DAMP的一个例子。因此，由DAMP-PRR相互作用例示的危险信号传导代表了损伤后免疫系统激活的范例。许多下游信号传导和器官反应在这些起始事件的下游发生。我们的机制驱动的方法已被证明是有用的，以确定一些关键的途径和介质。然而，随着信息量的扩大，我们已经认识到需要通过一系列数学模型来预测关键事件之间的关系，从而整合这些信息。这些模型的不断完善将来自于新的实验数据的整合和临床环境中实验数据的验证。最终，这些模型指导新假设的产生。 正如创伤和休克中的早期分子信号事件是高度整合的一样，我们的研究方法也是如此。这五个项目中的每一个项目都追求宿主对创伤和休克反应的一个明确方面。所有项目都通过完善的合作渠道和共同依赖三个组织良好的核心进行整合。项目I（Billiar）追求参与全身和肝脏炎症反应激活的机制，强调TLR 4，TLR 9和HMGB 1的作用。项目II（Hackam）探索了TLR 4和TLR 9在胃肠道粘膜功能障碍和损伤中的作用。项目III（Bauer）研究导致肠道运动功能衰竭的介质。该项目探讨了TLR 2上调对肠道运动变化的影响。项目IV（Fan）研究了导致损伤后炎性小体激活的途径，特别强调了这一过程中的TLR 4和HMGB 1。项目V（Vodovotz/Ochoa）将实验结果整合到损伤反应的数学模型中。项目V还通过收集创伤患者的临床数据将项目I-VI与临床方面联系起来，以纳入我们最具转化性的数学模型，用于模拟有希望的治疗方法的临床试验以及患者特异性结果预测。 通过共同使用三个组织良好的核心，这些合作和中心的总体目标将得到显着促进。动物模型核心（核心B）将提供在技术经验丰富的核心人员监督下接受标准化出血性休克和出血伴组织创伤方案的动物（主要是小鼠）的组织来源。这种方法保持了项目之间模型的一致性，并允许对结果进行详细的比较。结构成像核心（核心C）将在最先进的组织成像方面提供非凡的专业知识，包括免疫组织化学，共聚焦显微镜，电子显微镜，定量形态学和原位杂交。由于每个项目都测试了一个单独的假设，旨在确定出血性或创伤性休克组织中的分子事件，因此有效和准确的结构成像来定位这些变化对每个研究者来说都是必不可少的。行政核心（核心A）将提供确保富有成效的合作和沟通所需的关键组织。基于我们迄今为止的进展，我们完全相信，我们的方法将继续导致富有成效的合作和有效的测试一个新的和重要的假设。

Trauma is the leading cause of death in this country in people under the age of 54 years. Except for major head injury, hemorrhage/tissue trauma and its consequences are the most important causes of morbidity and mortality in these often young, otherwise healthy individuals. This Center Grant proposal seeks to advance our understanding of the molecular mechanisms leading to organ injury and dysfunction following trauma and hemorrhage. Our focus is on the events leading to the activation and propagation of inflammatory response with the view that the magnitude of the inflammatory response is the primary determinant of both early organ damage/dysfunction and delayed immune dysfunction following injury. Thus, understanding the inciting events could lead to effective approaches to limit not only the early organ damage but also the susceptibility to late sepsis and multiple organ failure (MOF). We propose that one of the keys to understanding organ injury resulting from hemorrhagic shock is to characterize the earliest molecular events leading to the initiation and propagation of inflammatory changes following the traumatic event. From previous funding cycles, we know that the initiation of inflammatory and stress signaling occurs quickly after the induction of shock and that the amplification of these responses involves a series of overlapping events. Our most recent efforts to identify the proximal steps have provided compelling evidence that pattern recognition receptors (PRR) of the innate immune system (Toll-like receptors) are engaged early following injury and both initiate and drive the inflammatory response. TLR4 and TLR9 are required for the activation of inflammatory signaling, while TLR2 and TLR4 are markedly unregulated and can induce an exaggerated inflammatory response if triggered by microbial ligands. Data from our PI's indicate tissue-specific expression and function patterns for TLR2 and TLR9. Endogenous activators of TLR signaling known as Damage-Associated Molecular Pattern (DAMP) molecules appear to drive the initial activation of TLR4 and TLR9. The nuclear protein high mobility group box-1 (HMGB1) is clearly involved in this process, and serves as an example of a prototypic DAMP in our trauma models. Thus, the danger signaling exemplified by the DAMP-PRR interaction represents a paradigm for the activation of the immune system post-injury. Much of the downstream signaling and organ response follows downstream from these initiating events. Our mechanism-driven approach has proven useful to identify some of the key pathways and mediators. However, as the quantity of information has expanded, we have recognized the need to integrate this information via a series of mathematical models that predict the relationship among key events. Constant refinement of these models will come from the incorporation of new experimental data and validation of experimental data in the clinical setting. Ultimately, these models guide the generation of new hypotheses. Just as the early molecular signaling events in trauma and shock are highly integrated, so is our research approach. Each of the five projects pursues a defined aspect of the host response to trauma and shock. All of the projects are integrated through well-established collaborative channels and co-reliance on three well-organized cores. Project I (Billiar) pursues the mechanisms involved in the activation of the systemic and hepatic inflammatory response emphasizing the roles of TLR4, TLR9, and HMGB1. Project II (Hackam) explores the roles of TLR4 and TLR9 in the dysfunction and damage to the Gl mucosa. Project III (Bauer) studies the mediators leading to gut motor function failure. This project explores the consequences of TLR2 upregulation on intestinal motility changes. Project IV (Fan) examines the pathways leading to the activation of the inflammasome post-injury, with a particular emphasis on TLR4 and HMGB1 in this process. Project V (Vodovotz/Ochoa) integrates the experimental findings into mathematical models of the injury response. Project V also links projects l-VI with the clinical side by gathering clinical data on trauma patients for incorporation into our most translational mathematical model, used for simulated clinical trials of promising therapies as well as for patient-specific outcome prediction. These collaborations and the overall goal of the center will be promoted significantly by the common use of three well-organized cores. The Animal Models Core (Core B) will provide a source of tissues from animals (primarily mice) subjected to standardized protocols of hemorrhagic shock and hemorrhage with tissue trauma under the supervision of technically experienced core personnel. This approach maintains consistency of the models between the projects and permits a detailed comparison of results. The Structural Imaging Core (Core C) will provide extraordinary expertise in state-of-the-art tissue imaging, including immunohistochemistry, confocal microscopy, electron microscopy, quantitative morphology, and in situ hybridization. Since each of the projects tests an individual hypothesis that seeks to identify the molecular events in tissues in hemorrhagic or traumatic shock, efficient and accurate structural imaging to localize these changes is essential to each investigator. The Administrative Core (Core A) will provide the critical organization needed to assure productive collaboration and communication. Based on our progress thus far, we are fully confident that our approach will continue to lead to productive collaboration and effective testing of a novel and important hypotheses.