Neutrophil Priming in Trauma and Sepsis

描述（由申请人提供）：创伤和败血症后的中性粒细胞启动和激活是导致成人呼吸窘迫综合征（ARDS），急性肺损伤（ALI）和多器官衰竭综合征（MOSF）的关键事件。损伤和败血症后，细胞因子引发呼吸爆发，导致NADPH氧化酶产生过多的超氧化物，导致自身炎症组织损伤。然而，许多涉及NADPH氧化酶的启动和激活的分子机制仍然不明确。我们的长期目标是对蛋白激酶和脂质激酶信号通路（包括PI 3-激酶途径、p38MAPK途径和Erk1/2途径）在启动和激活过程中如何调节中性粒细胞NADPH氧化酶的组装、亚细胞靶向和活性进行详细的分子理解。我们之前的工作和初步观察发现p47phox和p40phox亚基中的PX结构域是与PI 3-激酶的特定脂质产物结合的模块化蛋白质结构域，并表明启动剂PAF和TNF1诱导p47phox:p67phox:p40phox异三聚体复合物在启动但未激活的细胞的细胞质中组装。在本研究中，我们利用生物化学、细胞生物学和小鼠模型研究了PX结构域介导的与脂质和细胞骨架的相互作用，以及p47phox与含PDZ结构域蛋白的结合在中性粒细胞启动和激活中的重要性。此外，我们进一步探索了蛋白激酶依赖的分子机制，涉及在启动过程中异源三聚体的形成。这些研究的结果可能有助于开发新的诊断或治疗试剂，旨在限制患者因败血症和创伤而遭受的自身炎症组织损伤。创伤和败血症后的中性粒细胞启动和激活是导致成人呼吸窘迫综合征（ARDS）、急性肺损伤（ALI）和多器官衰竭综合征（MOSF）的关键事件，这是成人外科重症监护病房死亡的主要原因。损伤和败血症后，细胞因子引发中性粒细胞呼吸爆发，导致NADPH氧化酶产生过量的超氧化物，并导致这些综合征中所见的自身炎症组织损伤。我们的研究旨在更好地了解创伤和败血症后NADPH氧化酶的调节，并促进新型诊断和治疗药物的开发，以减少这些危重患者的组织损伤，发病率和死亡率。

DESCRIPTION (provided by applicant): Neutrophil priming and activation following trauma and sepsis is a key event implicated in causing Adult Respiratory Distress Syndrome (ARDS), Acute Lung Injury (ALI) and Multi-Organ Failure Syndrome (MOSF). Priming of the respiratory burst by cytokines following injury and sepsis results in excessive superoxide production by the NADPH oxidase leading to auto-inflammatory tissue damage. Many of the molecular mechanisms involved in priming and activation of the NADPH oxidase, however, remain poorly defined. Our long-term goal is to develop a detailed molecular understanding of how protein kinase and lipid kinase signaling pathways, including the PI 3-kinase pathway, the p38MAPK pathway and the Erk1/2 pathways regulate the assembly, subcellular targeting, and activity of the neutrophil NADPH oxidase during priming and activation. Our previous work and preliminary observations identified PX domains in the p47phox and p40phox subunits as modular protein domains that bind to specific lipid products of PI 3-kinase, and showed that the priming agents PAF and TNF1 induced the assembly of a p47phox:p67phox:p40phox heterotrimeric complex in the cytoplasm of primed but un-activated cells. In the studies outlined in this proposal we investigate the importance of PX domain-mediated interactions with lipids and the cytoskeleton, and p47phox binding to PDZ- domain-containing proteins, in neutrophil priming and activation using biochemistry, cell biology and mouse models. In addition, we further explore protein kinase-dependent molecular mechanisms involved in heterotrimer formation during priming. The results from these studies may assist in the development of novel diagnostic or therapeutic reagents aimed at limiting the auto-inflammatory tissue damage patients suffer as a result of sepsis and trauma. PUBLIC HEALTH RELEVANCE3 Neutrophil priming and activation following trauma and sepsis is a key event implicated in causing Adult Respiratory Distress Syndrome (ARDS), Acute Lung Injury (ALI) and Multi-Organ Failure Syndrome (MOSF), which are the leading causes of death in adult surgical intensive care units. Priming of the neutrophil respiratory burst by cytokines following injury and sepsis results in excessive superoxide production by the NADPH oxidase and contributes to the auto-inflammatory tissue damage seen in these syndromes. Our research is designed to better understand regulation of the NADPH oxidase following trauma and sepsis, and facilitate the development of novel diagnostic and therapeutic agents that will reduce tissue damage, morbidity and mortality in these critically ill patients.