Mechanisms of trauma and hemorrhage-induced impairment of innate immunity

创伤和出血引起的先天免疫受损的机制

• 批准号: 8803318
• 负责人: Xiao-Di Tan
• 金额: --
• 依托单位: JESSE BROWN VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8803318
• 关键词: Adverse effects; Affect; Air; Attenuated; Autophagocytosis; Autophagosome; Bacteremia; Bacteria; Bacterial Infections; Binding; Binding Proteins; Cause of Death; Cell physiology; Cells; Clinical; Complex; Data; Development; Disease; Down-Regulation; Epithelial; Epithelial Cells; Epithelium; Eukaryotic Cell; Event; Face; Functional disorder; Gene Expression; Gene Silencing; Genes; Health; Hemorrhage; Hemorrhagic Shock; Hospital Charges; Human; Immune; Immune system; Immunity; Impairment; In Vitro; Individual; Infection; Inflammation; Inflammation Mediators; Inflammatory Response Pathway; Injury; Invaded; Knowledge; Length of Stay; Lung; Mediating; Mediator of activation protein; Medical center; Membrane; Microbe; Modeling; Molecular; Molecular Biology; Morbidity - disease rate; Mucous Membrane; Mus; Natural Immunity; Nature; Norepinephrine; Operative Surgical Procedures; Patients; Peptidoglycan; Phagocytes; Physicians; Play; Pneumonia; Predisposition; Probiotics; Process; Proteins; Pseudomonas aeruginosa; Research; Role; Scientist; Sepsis; Stress; Subfamily lentivirinae; Surface; Surgeon; Survival Rate; System; Technology; Testing; Tissues; Trauma; Validation; Work; attenuation; base; clinical application; high risk; in vivo; innate immune function; knockout gene; mortality; novel; novel therapeutic intervention; pathogen; promoter; respiratory; trauma units; treatment strategy

DESCRIPTION (provided by applicant): Trauma and hemorrhagic shock are critical surgical conditions that are managed daily by surgeons and physicians in VA medical centers. It rapidly triggers suppression of innate immune system, leading to an increased susceptibility to infections. Previously, physicians and scientists have extensively studied whether and how the function of innate immune cells is disrupted by severe trauma and hemorrhagic shock. In contrast, our knowledge about molecular mechanisms involved in impairment of innate immunity in non-immune cells by severe trauma and hemorrhagic shock is limited. Thus, the objective of our long-term research is to study effects of severe trauma and hemorrhagic shock on non-immune cell function against infections and molecular mechanisms involved. Recent studies have revealed that autophagic machinery is a critical innate immune effector against intracellular microbes for non-phagocytic cells. Particularly, Atg12 has been shown to play an important role in eliminating invaded bacteria by epithelial cells. In this project, we will test our central hypothesis that trauma and hemorrhage induce down-regulation of Atg12 in lung epithelial cells, which in turn impairs Atg12-dependent innate defense system against opportunistic pathogens in lung epithelial cells. In Specific Aim 1, we will characterize the effect of sublethal hemorrhage stress on Atg12 expression in lungs using a molecular biology approach. A classic murine hemorrhage model will be used. Furthermore, we will study whether hemorrhage-induced alteration of Atg12 is associated with increase in susceptibility to Pseudomonas aeruginosa infection in lungs. In addition, we will investigate whether knockdown of Atg12 results in attenuation of eliminating bacteria by lung epithelial cells in vitro using a lentivirus-based gene silencing approach. Finally, we will delete Atg12 in lung epithelial cells in vivo using a novel gene knockout approach and examine whether lung epithelial-specific down-regulation of Atg12 contributes to impairing pulmonary innate immunity against P. aeruginosa infection in mice. In Specific Aim 2, we will investigate molecular mechanisms by which surgical insult-derived proinflammatory inflammatory mediators alter Atg12 gene expression in human respiratory epithelial cells. Specifically, we will characterize specific binding motifs in the promoter of human Atg12 gene and their binding proteins, and study their role in alteration of expression of Atg12 during severe surgical circumstances. The standard approach for analysis of the gene promoter function will be applied. In Specific Aim 3, we investigate whether a nature molecule is able to preserve Atg12 levels in respiratory epithelial cells, which in turn sustains innate immunity in lungs during severe surgical conditions. The studies involve infection of post-hemorrhaged mice with Pseudonumo aeruginosa followed by assessing the clinical course including survival rate, bacteremia, tissue injury, and inflammatory and cytokine response. At the completion of this project, we will provide novel mechanisms by which severe surgical stresses (i.e. trauma and hemorrhage) suppress innate immune function in non-phagocytes. This work will expand our knowledge on understanding and treatment of suppression of innate immunity in patients under severe surgical circumstances.

描述（由申请人提供）： 创伤和出血性休克是弗吉尼亚州医疗中心的外科医生和医生每天管理的关键手术状况。它迅速触发了对先天免疫系统的抑制，从而增加了对感染的敏感性。以前是医生和科学家 已经广泛研究了先天免疫细胞的功能以及如何因严重的创伤和出血性休克而破坏。相比之下，我们对严重创伤和出血性休克对非免疫细胞损害的分子机制的了解受到限制。因此，我们长期研究的目的是研究严重创伤和出血性休克对涉及的感染和分子机制的非免疫细胞功能的影响。最近的研究表明，自噬机械是针对非吞噬细胞的细胞内微生物的关键先天免疫效应子。特别是，ATG12已显示在消除上皮细胞入侵细菌方面起重要作用。在该项目中，我们将测试我们的中心假设，即创伤和出血会诱导肺上皮细胞中ATG12的下调，这反过来又损害了ATG12依赖性的先天防御系统，以针对肺上皮细胞中的机会性病原体。在特定的目标1中，我们将使用分子生物学方法来表征肺部出血应激对肺中ATG12表达的影响。将使用经典的鼠出血模型。此外，我们将研究出血诱导的ATG12改变是否与肺中铜绿假单胞菌感染的易感性增加有关。此外，我们将研究ATG12的敲低是否导致使用基于慢病毒的基因沉默方法在体外通过肺上皮细胞消除细菌的衰减。最后，我们将删除 使用一种新型基因敲除方法在肺上皮细胞中的ATG12体内，并检查ATG12的肺上皮特异性下调是否有助于损害针对小鼠铜绿假单胞菌感染的肺先天免疫。在特定的目标2中，我们将研究分子机制，通过这些机制，手术损伤促炎性炎症介质改变了人呼吸性上皮细胞中ATG12基因的表达。具体而言，我们将表征人ATG12基因及其结合蛋白的启动子中特定的结合基序，并研究它们在严重的手术情况下ATG12表达的改变中的作用。将采用分析基因启动子功能的标准方法。在特定的目标3中，我们研究了自然分子是否能够在呼吸道上皮细胞中保留ATG12水平，进而在严重的手术条件下维持肺部的先天免疫力。该研究涉及吞噬后小鼠的感染铜绿假病，然后评估临床病程，包括存活率，菌血症，组织损伤以及炎症和细胞因子反应。该项目完成后，我们将提供新的机制，通过这些机制，严重的手术应激（即创伤和出血）抑制了非斑点细胞中的先天免疫功能。这项工作将扩大我们在严重的手术情况下对患者的先天免疫抑制的理解和治疗的知识。