Phospholipase A2-mediated surfactant hydrolysis and dysfunction in ALI and ARDS

ALI 和 ARDS 中磷脂酶 A2 介导的表面活性剂水解和功能障碍

• 批准号: 7414068
• 负责人: Robert Duncan Hite
• 金额: $ 36.69万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7414068
• 关键词: Acute; Acute Lung Injury; Acute respiratory failure; Address; Adult Respiratory Distress Syndrome; Air; Alveolar; Binding; Biochemical; Bronchoalveolar Lavage; Bronchoalveolar Lavage Fluid; Cell model; Cells; Clinical; Clinical Data; Educational workshop; Epithelial Cells; Etiology; Family; Film; Functional disorder; Gene Activation; Genes; Hydrolysis; In Vitro; Individual; Inflammatory; Injury; Intervention Studies; Leukocytes; Lipids; Liquid substance; Lung; Lysophospholipids; Measures; Mediating; Mediator of activation protein; Messenger RNA; Modeling; Multiple Abnormalities; Newborn Respiratory Distress Syndrome; Outcome; Pathogenesis; Pathway interactions; Patients; Pattern; Phase; Phosphatidyl glycerol; Phosphatidylglycerols; Phospholipase A2; Phospholipids; Play; Production; Property; Proteins; Pulmonary Surfactant-Associated Protein B; Pulmonary Surfactants; Recombinants; Recovery; Regulation; Research Personnel; Respiratory Failure; Respiratory physiology; Role; Sampling; Substrate Specificity; Surface; Testing; Time; Variant; cytokine; in vivo; macrophage; multidisciplinary; neutrophil; pressure; programs; surfactant; surfactant deficiency

DESCRIPTION (provided by applicant): Surfactant deficiency and injury is an important component in the pathogenesis of acute lung injury (ALI)and acute respiratory distress syndrome (ARDS). Analysis of bronchoalveolar lavage (BAL) samples from ALI/ARDS patients reveal multiple abnormalities including decreased total surfactant phospholipid with a disproportionately greater decrease in phosphatidylglycerol (PG). PG is critical to maintain optimal surface activity through its interactions with surfactant protein B (SP-B). Secretory phospholipases A2 (sPLA2) are potent mediators of surfactant injury, and are increased in the BAL fluid in ALI/ARDS. Depletion of PG is a key mechanism in sPLA2-mediated surfactant dysfunction. Identification of specific sPLA2 and mechanisms regulating secretion are unknown in ARDS. This proposal will examine the hypothesis that specific secretory phospholipases A2 released during the inflammatory phase of ALI and ARDS hydrolyze pulmonary surfactant phospholipids, decrease PG and play a major role in limiting endogenous surfactant function and clinical recovery from acute respiratory failure. This hypothesis will be tested as follows: Specific Aim 1. Measure bronchoalveolar phospholipase A2 and surfactant abnormalities during the course of ALI/ARDS. BAL fluid will be obtained from ALI/ARDS patients (n = 80) early in the course of respiratory failure and serial samples will be obtained over the course of respiratory failure. Components of the BAL (cells, surfactant pellet and supernatant) will be analyzed and the associations with important clinical variables of ARDS etiology, respiratory failure and ARDS outcome will be established. Specific Aim 2. Determine the mechanisms regulating sPLA2 expression and secretion. sPLA2 proteins secreted into the BAL will be identified and the regulation of sPLA2 synthesis and release from cell models measured in vitro to test the hypothesis that there is a cytokine driven stimulation of sPLA2 secretion from specific cells in the lung. Cytokine analysis of the BALs in Aim 1 will be used to further direct these studies. Specific Aim 3. Determine the mechanisms that regulate sPLA2-mediated surfactant hydrolysis and dysfunction. The impact of the surfactant proteins (SP) and the alveolar phospholipid forms (bulk aggregates in the subphase and monomolecular films at the air-liquid interface) on sPLA2 hydrolysis, PG depletion and surfactant dysfunction will be examined. Interpretation of the in vivo relevance of these results will be enhanced by measuring SP levels in the BALs from Aim 1. This multicenter, multidisciplinary analysis directly addresses the NHLBI ALI Workshop priority to investigate biochemical predictors of ALI, and is essential to develop effective clinical intervention studies involving suppression of sPLA2 activity and surfactant replacement.

描述（由申请人提供）：表面活性剂缺乏和损伤是急性肺损伤（ALI）和急性呼吸遇险综合征（ARDS）发病机理中的重要组成部分。分析来自ALI/ARDS患者的支气管肺泡灌洗（BAL）样品显示多种异常，包括总表面活性剂磷脂降低，磷脂酰甘油（PG）的降低不成比例降低。 PG对于通过与表面活性剂蛋白B（SP-B）的相互作用来维持最佳表面活性至关重要。分泌磷酸酶A2（SPLA2）是表面活性剂损伤的有效介质，在ALI/ARDS的BAL液中增加。 PG的耗竭是SPLA2介导的表面活性剂功能障碍的关键机制。特定SPLA2的识别和调节分泌的机制在ARDS中未知。该提案将研究以下假设：在ALI的炎症阶段释放的特​​定分泌磷脂酶A2和ARDS水解肺表面活性剂磷脂，降低PG并在限制内源性表面活性剂功能和急性呼吸衰竭中临床恢复中起着重要作用。该假设将进行如下检验： 特定目标1。在衡量支气管肺泡磷脂酶A2和表面活性剂异常期间 Ali/ards的课程。 BAL液将在早期的ALI/ARDS患者（n = 80）中获得 在呼吸衰竭过程中，将获得呼吸衰竭和连续样品。将分析BAL（细胞，表面活性剂颗粒和上清液）的成分，并将建立与重要的ARDS病因，呼吸衰竭和ARDS结果的重要临床变量的关联。具体目的2。确定调节SPLA2表达和分泌的机制。将确定分泌到BAL的SPLA2蛋白，并从体外测量的细胞模型中调节SPLA2合成和释放，以检验以下假说，即在肺中有细胞因子驱动的SPLA2分泌的刺激。 AIM 1中BAL的细胞因子分析将用于进一步指导这些研究。具体目标3。确定调节SPLA2介导的表面活性剂水解和功能障碍的机制。表面活性剂蛋白（SP）和肺泡磷脂形式（在空气液体界面的亚相和单分子膜中的大量聚集体）对SPLA2水解，PG耗竭和表面活性剂功能障碍的影响。通过测量AIM 1的BALS中的SP水平，可以增强对体内相关性的解释。该多中心多学科分析直接解决了NHLBI ALI ALI研讨会优先级，以研究ALI的生物化学预测因素，并且对于开发涉及Spla2 Actipement抑制抑制spla2 Actionement和curfactations的有效临床干预研究至关重要。