Angiopoietin Mechanisms in Sepsis

脓毒症中的血管生成素机制

• 批准号: 7837332
• 负责人: Samir M Parikh
• 金额: $ 29.43万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7837332
• 关键词: Accident and Emergency department; Accounting; Acute; Adenoviruses; Adherens Junction; Adhesions; Admission activity; Adult; Affect; Angiopoietin-1; Angiopoietin-2; Angiopoietins; Animal Experiments; Area; Basic Science; Binding; Blood Vessels; Bradykinin; CNTNAP1 gene; Cellular Morphology; Cessation of life; Clinical Research; Competence; Cytoplasmic Tail; Data; Defense Mechanisms; Diabetes Mellitus; Diagnostic; Disease; Endothelial Cells; Endothelium; Endotoxemia; Endotoxins; Epidemiology; Family; Fibroblasts; Future; Gold; Histamine; Hospitals; Human; In Vitro; Incidence; Individual; Inflammation; Inflammation Mediators; Inflammatory; Injury; Investigation; Knockout Mice; Laboratories; Lead; Learning; Ligands; Ligation; Measures; Mediating; Mediator of activation protein; Modeling; Molecular; Mus; NADPH Oxidase; Outcome; Oxidants; Pathogenesis; Pathology; Patient Care; Patients; Perforation; Performance; Permeability; Pilot Projects; Predictive Value; Prospective Studies; Protein Binding; Protein Dephosphorylation; Proteins; Public Health; Publications; Publishing; RNA Interference; Reactive Oxygen Species; Receptor Protein-Tyrosine Kinases; Regulation; Reporting; Research; Rodent; Rodent Model; Role; Sepsis; Serotonin; Serum; Severity of illness; Shock; Signal Transduction; Stimulus; Stroke; Structure; TEK gene; Testing; Therapeutic; Vascular Permeabilities; Wild Type Mouse; base; cadherin 5; cell type; chemical genetics; cost; design; experience; genetic regulatory protein; human subject; improved; in vitro Assay; in vivo; injured; insight; macular edema; mortality; multidisciplinary; neutralizing antibody; novel; novel diagnostics; prevent; prognostic; prospective; protective effect; public health relevance; receptor; research study; response; rho; rho GTP-Binding Proteins; septic

DESCRIPTION (provided by applicant): Sepsis affects more than 300,000 individuals in the US annually, costs more than $16 billion/yr to treat, is associated with an acute mortality of 30%, and is expected to increase in incidence, making this disease a major public health concern. Care of these patients has remained primarily supportive despite intensive basic and clinical research efforts. Novel insights into its pathogenesis that can be applied to patient care are sorely needed. Our laboratory is studying the endothelium as a cell type that is injured in sepsis and that, in turn, mediates further damage to the host. Specifically, we are studying the angiopoietins a class of secreted proteins that act on endothelial cells through the Tie-2 receptor as regulators of vascular permeability in this disease. We have found that circulating angiopoietin-2 (Ang-2) is elevated in human subjects with severe sepsis, and that excess Ang-2 is sufficient to promote leak across endothelial cells and in otherwise healthy adult mice. More recently published studies of Ang-2 null mice have further validated Ang-2 as a mediator of increased permeability during inflammation. We have also found that angiopoietin-1 (Ang-1), which is similar in structure to Ang-2 but has opposite signaling effects, prevents vascular leak in murine endotoxemia. To achieve this remarkable protective effect, Ang-1 must activate a regulatory protein in the Rho-GTPase family called p190RhoGAP. In vivo depletion of p190RhoGAP is sufficient to abrogate the protection conferred by Ang-1 against endotoxin. These findings have led us to hypothesize that derangements in angiopoietins via excess Ang-2 and/or insufficient Ang-1 contribute to the marked hyperpermeability of sepsis. To explore this central question, we will apply the gold-standard model of rodent sepsis, cecal ligation and perforation, to Ang- 2 null mice, and wild-type mice treated either with a potent Ang-2 neutralizing antibody or with an Ang-1 expressing adenovirus to evaluate survival, permeability, and cellular responses (Aim 1). Given the unexpected ability of Ang-1 to counteract endotoxin-mediated permeability via p190RhoGAP activation, we will explore this mechanism of barrier defense further (Aim 2). Finally, we will return to human subjects with sepsis to perform a prospective study based in our emergency department to evaluate the predictive value of early changes in circulating Ang-2 and Ang-1 for death, shock, and other adverse outcomes (Aim 3). Aims 1 and 3 are highly translational, and Aim 2 will substantially elucidate endothelial barrier defense mechanisms in sepsis. Pilot data are strongly supportive of each aim, the team we have assembled has extensive experience in collaborative research (basic science, clinical research, pathology and epidemiology) in the area of sepsis, and testing each aim will be cost-efficient. These targeted studies will improve our understanding of the pathogenesis of sepsis, and potentially lead to novel diagnostic and therapeutic options for patients with severe sepsis. PUBLIC HEALTH RELEVANCE Sepsis is a common, costly, and lethal disease of increasing incidence; it may already account for 10% of all deaths in the US, making it a major public health threat whose impact is only likely to grow. Based on extensive preliminary data, we believe that angiopoietins may be critically involved in the pathogenesis of this disease. The proposed experiments will enable us to evaluate the diagnostic and therapeutic potential of these proteins in sepsis.

描述（由申请人提供）：败血症每年在美国影响30万以上的人，需要治疗的费用超过160亿美元，与30％的急性死亡率有关，预计发病率将增加，这使得这种疾病成为主要的公共卫生问题。尽管基础和临床研究工作进行了大量的基础和临床研究，对这些患者的护理仍主要支持。迫切需要对可应用于患者护理的发病机理的新见解。我们的实验室将内皮研究是一种细胞类型，在败血症中受伤，然后介导对宿主的进一步损害。具体而言，我们正在研究血管生成素的一类分泌蛋白质，这些蛋白质通过TIE-2受体对内皮细胞作用，作为该疾病中血管通透性的调节剂。我们已经发现，在严重败血症的人类受试者中，循环血管生成素-2（ANG-2）升高，并且过量的Ang-2足以促进内皮细胞和其他健康的成年小鼠的泄漏。最近发表的对ANG-2无效小鼠的研究已进一步验证了ANG-ANG-2作为炎症过程中渗透率增加的介体。我们还发现，在结构上与ANG-2相似但具有相反信号效应的血管生成素-1（Ang-1）可防止鼠内毒素血症的血管泄漏。为了达到这种显着的保护作用，ANG-1必须激活称为P190RHOGAP的Rho-GTPase家族中的调节蛋白。 P190RHOGAP的体内耗竭足以消除Ang-1对内毒素的保护。这些发现使我们假设血管生成素的危险通过过量的ANG-2和/或ANG-1不足有助于败血症的明显高度过敏性。为了探讨这个中心问题，我们将应用啮齿动物败血症，盲肠连接和穿孔的金色标准模型，以及用有效的Ang-2中和抗体处理的野生型小鼠，以及用Ang-1表达腺病毒的野生型小鼠，以评估生存率，允许性和蜂窝响应（AIL 1）。鉴于Ang-1通过P190RHOGAP激活抵消内毒素介导的渗透性的意外能力，我们将进一步探索这种屏障防御的机制（AIM 2）。最后，我们将返回带有败血症的人类受试者，以在急诊室进行一项前瞻性研究，以评估循环ANG-2和ANG-1的早期变化的预测价值，例如死亡，冲击和其他不良结果（AIM 3）。目标1和3是高度转化的，AIM 2将基本阐明败血症中的内皮屏障防御机制。试点数据强烈支持每个目标，我们组装的团队在败血症领域的合作研究（基础科学，临床研究，病理学和流行病学）方面具有丰富的经验，并且测试每个目标的成本效益。这些有针对性的研究将提高我们对败血症发病机理的理解，并可能导致严重败血症患者的新型诊断和治疗选择。公共卫生相关性败血症是发病率增加的一种常见，昂贵且致命的疾病。它可能已经占美国所有死亡人数的10％，使其成为主要的公共卫生威胁，其影响只有可能增长。基于广泛的初步数据，我们认为血管生成素可能与该疾病的发病机理有关。提出的实验将使我们能够评估败血症中这些蛋白质的诊断和治疗潜力。