Protective activity of the lectin-like domain of TNF in permeability edema

TNF 凝集素样结构域对通透性水肿的保护活性

• 批准号: 8308361
• 负责人: Rudolf Lucas
• 金额: $ 37.13万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8308361
• 关键词: 5 year old; Affect; Affinity Chromatography; Agonist; Alveolar; Antibiotic Therapy; Arginine; Bacterial Infections; Bacterial Pneumonia; Bacterial exotoxin; Cause of Death; Cells; Cessation of life; Child; Cholesterol; Complication; Data; Development; Disease; Down-Regulation; Edema; Elderly; Enzyme Uncoupling; Enzymes; Epithelial; Epithelial Cells; Event; Exotoxins; Functional disorder; Generations; Goals; Human; In Vitro; Infection; Influenza A virus; Knock-in Mouse; Lead; Lectin; Life; Liquid substance; Listeria monocytogenes; Listeria monocytogenes hlyA protein; Lung; Mediating; Membrane; Mus; NADPH Oxidase; Patients; Peptide N-glycohydrolase F; Peptides; Permeability; Phosphorylation; Play; Pneumonia; Production; Protein Kinase C; Research; Role; Secondary to; Small Interfering RNA; Sodium; Sodium Channel; Sterility; Streptococcus pneumoniae; Streptococcus pneumoniae plY protein; TNF gene; Testing; Tissues; Toxin; Vascular Permeabilities; Virulence Factors; Virus Diseases; Wild Type Mouse; aged; arginase; base; combat; epithelial Na+ channel; improved; in vivo; inhibitor/antagonist; mortality; mouse model; mutant; novel therapeutic intervention; novel therapeutics; patch clamp; programs; protein expression; public health relevance; rhoA GTP-Binding Protein; uptake

DESCRIPTION (provided by applicant): Severe pneumonia is the leading single cause of mortality in children aged less than five years worldwide and the sixth leading cause of death in seniors over age 65 in the US. Streptococcus pneumoniae represents the main etiological agent of the disease. Moreover, mortality after influenza A virus (IAV) infection has been suggested to be mainly due to secondary pneumoccocal infections. Intriguingly, death in pneumococcal-induced pneumonia can occur days after initiation of antibiotic therapy, when tissues are sterile and the pneumonia is clearing. This mortality correlates with the presence of pneumococcal virulence factors, the most important one of which is the pore-forming toxin pneumolysin (PLY). A major complication of severe pneumonia is permeability edema, characterized by a dramatically increased pulmonary endothelial hyperpermeability and an impaired alveolar liquid clearance (ALC). The enzyme PKC-(, which is activated by PLY-mediated Ca2+ influx, has recently been suggested to be implicated in the downregulation of the epithelial sodium channel (ENaC) expression, as well as in endothelial barrier dysfunction. Our preliminary data demonstrate that the lectin-like domain of TNF, mimicked by the TIP peptide, is able to blunt PLY-induced PKC-( activation, endothelial hyperpermeability and ALC dysfunction. Our overall hypothesis is that the lectin-like domain of TNF restores alveolar liquid clearance and improves barrier integrity during G+-infection- associated pneumonia, by means of blunting exotoxin-mediated PKC-( activation. We will test three specific aims to this purpose. First, we will unravel the mechanism by which the TIP peptide restores epithelial sodium channel activity and expression in PLY-treated alveolar epithelial cells. Second, we will determine at which step(s) in the cascade of events leading to PLY-induced endothelial dysfunction, the TIP peptide intervenes and what is the most upstream event affected by the peptide. Third, we will test the hypothesis that the lectin-like domain of TNF restores ALC and preserves pulmonary endothelial barrier integrity in PLY-treated mice, upon blunting PKC-( activation, making use of Triple mTNF knock-in mice, expressing a lectin-deficient mutant of TNF. The results of this research program can thus provide important information about mechanisms leading to permeability edema and dysfunctional ALC during bacterial pneumonia and can thus lead to the identification of novel therapeutic strategies. PUBLIC HEALTH RELEVANCE: One of the major complications of severe bacterial pneumonia is permeability edema, characterized by endothelial hyperpermeability and a dysfunctional alveolar liquid clearance (ALC) capacity. Our recent data from mouse models and in vitro studies using human endothelial and airway epithelial cells indicate that the TNF-derived TIP peptide, mimicking its lectin-like domain, restores ALC and endothelial barrier integrity upon treatment with the G+ bacterial exotoxin pneumolysin (PLY). This project aims to demonstrate that the protective activity of the TIP peptide in bacterial pneumonia relies on its capacity to blunt PLY-induced Protein Kinase C-( activation, which plays a crucial role in both the induction of endothelial hyperpermeability and in the down-regulation of the epithelial sodium channel, as such providing a basis for novel therapeutic strategies to combat severe bacterial pneumonia.

描述（由申请人提供）：严重的肺炎是全世界不到五岁的儿童死亡的主要原因，也是美国65岁以上老年人的第六大死亡原因。肺炎链球菌代表了该疾病的主要病因。此外，已经提出流感病毒（IAV）感染后的死亡率主要是由于继发性肺炎遭到肺炎性肺炎性感染。有趣的是，肺炎球菌诱导的肺炎死亡可能发生在抗生素治疗的几天后，当组织不育并且肺炎清除。这种死亡率与肺炎球菌毒力因子的存在相关，其中最重要的是形成孔的毒素肺炎（PLY）。严重的肺炎的主要并发症是渗透性水肿，其特征是肺部内皮过度过度过敏性急剧增加和肺泡液体清除率（ALC）受损。 The enzyme PKC-(, which is activated by PLY-mediated Ca2+ influx, has recently been suggested to be implicated in the downregulation of the epithelial sodium channel (ENaC) expression, as well as in endothelial barrier dysfunction. Our preliminary data demonstrate that the lectin-like domain of TNF, mimicked by the TIP peptide, is able to blunt PLY-induced PKC-（激活，内皮过度过度性和ALC功能障碍。我们的总体假设是，TNF的凝集素样结构域恢复了肺泡液体清除率，并改善G+ - 接收性肺炎期间的G+ - 伴随肺炎，通过blunune介导的exotoxin介导的PKC（均具有三分性能）（我们将介绍了三个特征）（我们将测试三分之二的目标。尖端肽可恢复肺泡上皮细胞中的上皮钠通道活性和表达，其次，我们将确定在哪个步骤中，导致ply诱导的内皮功能障碍，尖端肽中心和最上方事件。第三，我们将检验以下假设：TNF的类似凝集素样结构域可恢复ALC并保留ply处理的小鼠中的肺内皮屏障完整性（激活，激活，使用三重MTNF敲击小鼠，都可以使TNF的静脉差异能够进行静态的突变，从而使凝集素有效地表达了tnf。细菌性肺炎期间的功能失调的ALC，因此可以导致鉴定出新的治疗策略。 公共卫生相关性：严重细菌性肺炎的主要并发症之一是渗透性水肿，其特征是内皮过度透露性和功能失调的肺泡液体清除率（ALC）。我们最新的数据来自小鼠模型的数据以及使用人内皮和气道上皮细胞进行的体外研究表明，TNF衍生的尖端肽在用G+细菌性外毒素肺炎（PLY）处理后，模仿其凝集素样域，模仿其凝集素样结构域，恢复ALC和内皮屏障完整性。 This project aims to demonstrate that the protective activity of the TIP peptide in bacterial pneumonia relies on its capacity to blunt PLY-induced Protein Kinase C-( activation, which plays a crucial role in both the induction of endothelial hyperpermeability and in the down-regulation of the epithelial sodium channel, as such providing a basis for novel therapeutic strategies to combat severe bacterial 肺炎。