COX2-Derived Cyclopentenone Prostaglandins Exacerbate Hypoxic Ischemic Brain Inju

COX2衍生的环戊烯酮前列腺素加剧缺氧缺血性脑损伤

基本信息

批准号：
7860386
负责人：
ROBERT W HICKEY
金额：
$ 22.73万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
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：
2009-06-05 至 2012-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7860386
关键词：
Affect Analytical Chemistry Animal Model Anoxia Arachidonic Acids Asphyxia Autophagocytosis Binding Brain Brain Hypoxia-Ischemia Brain Injuries Brain Ischemia Calcium Cardiac Cardiopulmonary Arrest Cell Death Cell Survival Cells Cerebral Ischemia Cerebrum Child Childhood Childhood Injury Coupled Data Degradation Pathway Development Disease Dose Drowning Eicosanoids Endoplasmic Reticulum Endoplasmic Reticulum Degradation Pathway Enzymes Event Heart Arrest Hippocampus (Brain)Hydrolase Hypoxia In Situ Nick-End Labeling In Vitro Incubated Injury Ischemia Knockout Mice Lead Mass Spectrum Analysis Measures Mediating Mediator of activation protein Messenger RNA Modeling Molecular Molecular Chaperones Neurologic Deficit Neuronal Injury Neurons Oxidative Stress Pathogenesis Pathway interactions Patients Printing Production Prostaglandin Production Prostaglandin Receptor Prostaglandins Protein Disulfide Isomerase Proteins Rattus Recombinant Proteins Recovery Reporting Research Resuscitation Rodent Model Role Secondary to Series Staining method Stains Sulfhydryl Compounds Survivors Techniques Testing Thioredoxin Thrombosis Toddler Translations Ubiquitin Ubiquitination United States arm base biological adaptation to stress brain tissue chemical reaction clinically relevant covalent bond cyclopentenone design disulfide bond endoplasmic reticulum stress foot in vivo inhibitor/antagonist knock-down multicatalytic endopeptidase complex natural hypothermia novel novel therapeutics overexpression protein aggregate protein degradation protein folding protein misfolding public health relevance research study response thioredoxin reductase

项目摘要

DESCRIPTION (provided by applicant): Cyloxygenase-2 (COX-2), the enzyme responsible for production of prostaglandins, has been identified as an important contributor to brain damage following hypoxia-ischemia. Unfortunately, COX-2 inhibitors have been reported to cause cerebral and cardiac thrombosis in patients, making COX-2 inhibition less attractive as a therapy for patients recovering from ischemic events. Thus, it is important to understand the mechanisms of COX-2 mediated neuronal injury so that more targeted therapies can be developed. Recently, downstream products of prostaglandins, specifically cyclopentenone prostaglandins have been identified as potential contributors to ischemic injury. The cyclopentenone prostaglandins are highly electrophilic and can form covalent bonds with exposed sulfhydryl groups of proteins. This chemical reaction can exacerbate recovery in reperfusing neurons by targeting nascent and denatured proteins thus contributing to endoplasmic reticulum (ER) stress. ER stress has been reported as an important component of ischemic injury. Further, cyclopentenones have been reported to bond and inactivate key component of the ER stress response. The ER stress response involves: 1) temporary cessation of translation of most mRNA (limiting the load of newly-formed, unfolded proteins) 2) selective translation of chaperone proteins to facilitate protein folding, and 3) recruitment of protein degradation pathways, including ubiquitination, the proteosome, and autophagy, to clear misfolded proteins. Cyclopentenone prostaglandins have been shown to bind with and inactivate key components of the ER stress response including thioredoxin, thioredoxin reductase, proteosome subunits, and ubiquitin hydrolase. We have identified a potential new target of this pathway, namely protein disulfide isomerase (PDI), an abundant ER protein responsible for proper folding of disulfide bonds in nascent or misfolded proteins. We are also the first to measure a cyclopentenone in post-ischemic brain tissue. We have been able to detect this highly reactive compound by using mass spectrometry in post-natal day 17 (PND 17) rat brains recovering from asphyxial cardiac arrest. The PND 17 rat is attractive as a model for this inquiry because it has very high constitutive expression of COX-2 and the insult mimics the most common cause of pediatric cardiac arrest (asphyxia) using a rat with developmental qualities similar to a toddler. Accordingly, we propose a series of experiments designed to investigate the hypothesis that COX-2 derived cyclopentenones worsen ER stress, in part by inhibiting PDI, in PND17 rats with asphyxial cardiac arrest. These experiments have the potential to identify new strategies for therapy in children suffering from brain injury following cardiac arrest. PUBLIC HEALTH RELEVANCE: This project will investigate a novel mechanism of brain injury following asphyxial cardiac arrest. We will use a rodent model mimicking pediatric cardiac arrest secondary to mechanisms such as drowning. The project has potential to identify therapies for brain injury in children suffering from cardiac arrest.

描述（由申请人提供）：环氧合酶-2（COX-2）是负责产生前列腺素的酶，已被确定为缺氧缺血后脑损伤的重要促成因素。不幸的是，据报道COX-2抑制剂会导致患者脑血栓和心脏血栓形成，使得COX-2抑制剂作为缺血性事件恢复患者的治疗方法不太有吸引力。因此，了解 COX-2 介导的神经元损伤的机制非常重要，以便开发更有针对性的治疗方法。最近，前列腺素的下游产物，特别是环戊烯酮前列腺素已被确定为缺血性损伤的潜在贡献者。环戊烯酮前列腺素具有高度亲电性，可以与蛋白质的暴露的巯基形成共价键。这种化学反应可以通过针对新生和变性蛋白质来加速再灌注神经元的恢复，从而导致内质网（ER）应激。据报道，内质网应激是缺血性损伤的重要组成部分。此外，据报道，环戊烯酮可以结合并灭活内质网应激反应的关键成分。 ER 应激反应包括：1) 暂时停止大多数 mRNA 的翻译（限制新形成的未折叠蛋白质的负载）2) 选择性翻译伴侣蛋白以促进蛋白质折叠，以及 3) 招募蛋白质降解途径，包括泛素化、蛋白酶体和自噬，以清除错误折叠的蛋白质。环戊烯酮前列腺素已被证明可以与 ER 应激反应的关键成分结合并使其失活，包括硫氧还蛋白、硫氧还蛋白还原酶、蛋白酶体亚基和泛素水解酶。我们已经确定了该途径的一个潜在新靶标，即蛋白质二硫键异构酶（PDI），这是一种丰富的内质网蛋白，负责新生或错误折叠蛋白质中二硫键的正确折叠。我们也是第一个测量缺血后脑组织中环戊烯酮的人。我们已经能够通过使用质谱法在从窒息心脏骤停中恢复的出生后第 17 天 (PND 17) 大鼠大脑中检测到这种高反应性化合物。 PND 17 大鼠作为本研究的模型很有吸引力，因为它具有非常高的 COX-2 组成型表达，并且使用具有与幼儿相似的发育质量的大鼠来模拟小儿心脏骤停（窒息）的最常见原因。因此，我们提出了一系列实验，旨在研究以下假设：COX-2 衍生的环戊烯酮在窒息心脏骤停的 PND17 大鼠中部分通过抑制 PDI 加重 ER 应激。这些实验有可能确定治疗心脏骤停后脑损伤儿童的新策略。公共卫生相关性：该项目将研究窒息性心脏骤停后脑损伤的新机制。我们将使用啮齿动物模型来模拟继发于溺水等机制的儿童心脏骤停。该项目有可能找到针对心脏骤停儿童脑损伤的治疗方法。