Angiopoietin Mechanisms in Sepsis

脓毒症中的血管生成素机制

基本信息

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
项目类别：
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

项目摘要

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）：脓毒症每年在美国影响超过 300,000 人，每年的治疗费用超过 160 亿美元，与 30% 的急性死亡率相关，并且预计发病率会增加，使这种疾病成为主要公共卫生问题。尽管进行了大量的基础和临床研究工作，但对这些患者的护理仍然主要是支持性的。迫切需要对其发病机制的新见解可应用于患者护理。我们的实验室正在研究内皮细胞作为一种在脓毒症中受损的细胞类型，进而介导对宿主的进一步损害。具体来说，我们正在研究血管生成素一类分泌蛋白，它们通过 Tie-2 受体作用于内皮细胞，作为这种疾病中血管通透性的调节剂。我们发现，患有严重脓毒症的人类受试者中，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成年小鼠的渗漏。最近发表的针对 Ang-2 缺失小鼠的研究进一步验证了 Ang-2 作为炎症过程中通透性增加的介质。我们还发现，血管生成素-1 (Ang-1) 与 Ang-2 结构相似，但具有相反的信号作用，可防止小鼠内毒素血症的血管渗漏。为了实现这种显着的保护作用，Ang-1 必须激活 Rho-GTPase 家族中称为 p190RhoGAP 的调节蛋白。体内 p190RhoGAP 的消耗足以消除 Ang-1 所赋予的针对内毒素的保护作用。这些发现使我们推测，Ang-2 过多和/或 Ang-1 不足导致血管生成素紊乱，导致脓毒症明显通透性过高。为了探索这个核心问题，我们将把啮齿动物败血症、盲肠结扎和穿孔的金标准模型应用于 Ang-2 缺失小鼠以及用强效 Ang-2 中和抗体或 Ang-2 治疗的野生型小鼠。 1 表达腺病毒以评估存活率、渗透性和细胞反应（目标 1）。鉴于 Ang-1 通过 p190RhoGAP 激活抵消内毒素介导的通透性的意外能力，我们将进一步探索这种屏障防御机制（目标 2）。最后，我们将回到患有败血症的人类受试者，在我们的急诊科进行一项前瞻性研究，以评估循环 Ang-2 和 Ang-1 的早期变化对死亡、休克和其他不良后果的预测价值（目标 3）。目标 1 和 3 具有高度转化性，目标 2 将充分阐明脓毒症中的内皮屏障防御机制。试点数据有力地支持了每个目标，我们组建的团队在脓毒症领域的合作研究（基础科学、临床研究、病理学和流行病学）方面拥有丰富的经验，并且测试每个目标都将具有成本效益。这些有针对性的研究将提高我们对脓毒症发病机制的理解，并有可能为严重脓毒症患者带来新的诊断和治疗选择。公共卫生相关性脓毒症是一种常见、昂贵且致命的疾病，发病率不断上升；它可能已经占美国所有死亡人数的 10%，使其成为一个重大的公共卫生威胁，其影响只会越来越大。基于大量的初步数据，我们认为血管生成素可能与该疾病的发病机制密切相关。拟议的实验将使我们能够评估这些蛋白质在脓毒症中的诊断和治疗潜力。