Altered innate leukocyte programming dynamics in sepsis

败血症中先天白细胞编程动力学的改变

基本信息

批准号：
10292455
负责人：
LIWU LI
金额：
$ 40.25万
依托单位：
VIRGINIA POLYTECHNIC INST AND ST UNIV
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-11-15 至 2023-10-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10292455
关键词：
Animal Model Attenuated Back Biological Models CCR5 gene Chemicals Complex Data Development Dose Event FPR2 gene Gene Expression Genes Genetic Transcription Goals Harvest Health Homeostasis Host Defense Human Immune In Vitro Inflammation Inflammatory Inflammatory Response Intervention Knockout Mice Leukocytes Lipopolysaccharides Lysosomes Mediating Modeling Molecular Morbidity - disease rate Mus Nature Paralysed Pathogenesis Pathologic Phase Phosphoric Monoester Hydrolases Prevention Process Resolution Runaway Seminal Sepsis Sterility System Systems Analysis Testing Tissues base cecal ligation puncture chromatin remodeling dosage extracellular genetic approach in vivo in vivo Model migration monocyte mortality neutrophil novel novel strategies novel therapeutic intervention preconditioning programs promoter restoration septic septic patients tauroursodeoxycholic acid

项目摘要

PROJECT SUMMARY Sepsis poses grave health concerns with no effective prevention or cure. The key stumbling block is the highly complex nature of the disrupted innate leukocyte homeostasis. Disrupted sepsis monocyte homeostasis is reflected in a dramatic early upswing of inflammatory processes followed by a late-phase compensatory tolerance. Disrupted neutrophil homeostasis in sepsis patients is cardinally represented by “migratory paralysis” in which septic neutrophils lose migratory potential toward bacterial products while retaining migration toward sterile tissues, due to preferential reduction of FPR2 and induction of CCR5. Septic neutrophils also have reduced potential for generating neutrophil extra-cellular trap (NET). Collectively, these disrupted innate leukocyte homeostasis may compromise host defense and exacerbate multi-organ inflammation. However, mechanisms underlying monocyte priming and neutrophil paralysis are poorly understood. Due to their highly dynamic natures, current experimental systems in vitro or animal models in vivo fail to properly capture the disrupted leukocyte homeostasis. The PI’s past systems analyses with experimental and computational approaches reveal a model system that recapitulates the disrupted human leukocyte homeostasis in vitro and in vivo by applying subclinical super-low dose lipopolysaccharide (LPS). In sharp contrast to the effects of widely used higher dosages LPS which preferentially facilitate monocyte tolerance, Dr. Li’s lab documented that super- low dose LPS “primes” monocytes for prolonged “run-away” inflammation. In addition, Li lab observed that super- low dose LPS “programs” neutrophils into a paralytic state, mimicking septic neutrophils with reduced FPR2, reduced potential of bacterial killing and elevated CCR5. Monocyte priming and neutrophil paralysis by super- low dose LPS can be observed in human blood leukocyte ex vivo. With the cecal ligation and puncture sepsis model, Li lab demonstrated exacerbated sepsis mortality in mice pre-conditioned with super-low dose LPS. Mechanistically, Li lab observed that super-low dose LPS potently reprograms monocytes and neutrophils by disrupting key homeostatic events and molecules. Based on these intriguing observations, the long-term goal is to understand the disrupted innate immune dynamics responsible for the elevated morbidity and mortality of sepsis. As a crucial first step, our key objective is to better understand the mechanisms responsible for the disrupted homeostasis in monocytes and neutrophils. This project plans to test the central hypothesis that monocyte priming and neutrophil paralysis during sepsis are caused by the disruption of key homeostatic molecules and processes. Aim 1 will test the hypothesis that the disruption of homeostatic molecules such as RelB is responsible for the monocyte priming conducive for increased sepsis mortality. Aim 2 will reveal the fundamental cellular and molecular mechanisms responsible for neutrophil paralysis. Aim 3 will test whether that alteration of leukocyte dynamics may exacerbate, while restoration of leukocyte homeostasis may attenuate sepsis pathogenesis.

项目概要脓毒症会带来严重的健康问题，且没有有效的预防或治疗方法。先天白细胞稳态被破坏的高度复杂性败血症单核细胞稳态被破坏。反映在炎症过程的早期剧烈上升，随后是晚期代偿败血症患者中性粒细胞稳态的破坏主要表现为“迁移性瘫痪”。其中脓毒性中性粒细胞失去向细菌产物迁移的潜力，同时保留向细菌产物的迁移能力由于 FPR2 的优先减少和 CCR5 的诱导，无菌组织也具有感染性中性粒细胞。产生中性粒细胞胞外陷阱（NET）的潜力降低，这些都破坏了先天性。白细胞稳态可能会损害宿主防御并加剧多器官炎症。由于对单核细胞启动和中性粒细胞麻痹的机制了解甚少。由于动态性质，当前的体外实验系统或体内动物模型无法正确捕获 PI 过去通过实验和计算进行的系统分析被破坏。方法揭示了一个模型系统，可以在体外和体内重现被破坏的人类白细胞稳态体内应用亚临床超低剂量脂多糖（LPS）的效果与广泛应用形成鲜明对比。使用较高剂量的 LPS 优先促进单核细胞耐受，李博士的实验室记录表明，超级低剂量的脂多糖“启动”单核细胞，导致长期“失控”的炎症。低剂量 LPS 将中性粒细胞“编程”至麻痹状态，模仿 FPR2 降低的脓毒症中性粒细胞，超级杀灭细菌的潜力降低，单核细胞启动和中性粒细胞麻痹升高。盲肠结扎和穿刺败血症可在离体人血白细胞中观察到低剂量的LPS。在模型中，李实验室证明，用超低剂量 LPS 预处理的小鼠败血症死亡率会加剧。从机制上讲，李实验室观察到，超低剂量的 LPS 通过以下方式有效地重新编程单核细胞和中性粒细胞：破坏关键的稳态事件和分子基于这些有趣的观察，长期目标。的目的是了解先天免疫动态被破坏，导致发病率和死亡率升高作为关键的第一步，我们的主要目标是更好地了解导致脓毒症的机制。该项目计划测试以下中心假设：单核细胞和中性粒细胞的稳态被破坏。败血症期间的单核细胞启动和中性粒细胞麻痹是由关键稳态破坏引起的目标 1 将检验稳态分子被破坏的假设，例如 RelB 负责单核细胞启动，导致脓毒症死亡率增加。目标 2 将揭示这一点。目标 3 将测试导致中性粒细胞麻痹的基本细胞和分子机制。白细胞动力学的改变可能会恶化，而白细胞稳态的恢复可能会减弱脓毒症发病机制。