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：
7656055
负责人：
ROBERT W HICKEY
金额：
$ 18.94万
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 2011-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7656055
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 Upper 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）：负责产生前列腺素的酶Cyloxygenase-2（Cox-2）已被确定为缺氧 - 缺血症后脑损伤的重要促进者。不幸的是，据报道，COX-2抑制剂会导致患者引起脑血栓形成，从而使COX-2抑制作用降低了吸引人的吸引力，作为一种从缺血性事件中恢复的患者的疗法。因此，重要的是要了解COX-2介导的神经元损伤的机制，以便可以开发出更多的靶向疗法。最近，前列腺素的下游产物，特别是环戊酮前列腺素被确定为缺血性损伤的潜在促进者。环戊烯酮前列腺素是高度亲电的，可以与暴露的蛋白质硫酸基团形成共价键。这种化学反应会通过靶向新生和变性的蛋白质，从而加剧恢复神经元的恢复，从而导致内质网胁迫（ER）胁迫。据报道，ER应力是缺血性损伤的重要组成部分。此外，据报道，环戊烯酮会键合，并使ER应力反应的关键组成部分结合并灭活。 ER应力反应涉及：1）暂时停止大多数mRNA的翻译（限制了新形成的，展开的蛋白质的负载）2）选择性翻译伴侣蛋白以促进蛋白质折叠的选择性翻译，3）募集蛋白质降解途径，包括蛋白质降解途径，包括蛋白质，蛋白质，蛋白质和自动蛋白质，蛋白质，蛋白质，蛋白质，清楚地误差了。环戊烯酮前列腺素已显示与ER应激反应的关键成分结合，包括硫氧还蛋白，硫氧还蛋白还原酶，蛋白质体亚基和泛素水解酶。我们已经确定了该途径的潜在新靶标，即蛋白二硫化物异构酶（PDI），这是一种丰富的ER蛋白，负责在新生或错误折叠蛋白中正确折叠二硫键。我们也是第一个在缺血后脑组织中测量环戊酮的人。我们已经能够通过在产后第17天（PND 17）大脑大脑中使用质谱法检测到这种高反应性化合物，从而从沥青心脏骤停中恢复。 PND 17大鼠作为此询问的模型具有吸引力，因为它具有很高的COX-2的构成表达，并且侮辱性地模仿了使用类似于幼儿的发育品质的大鼠使用大鼠的小儿心脏骤停（窒息）。因此，我们提出了一系列实验，旨在研究COX-2衍生的环烯酮的假设使ER应激恶化，部分是通过抑制PDI的PND17大鼠，并在PND17大鼠中抑制了窒息心脏骤停。这些实验有可能确定心脏骤停后患有脑损伤的儿童治疗的新策略。公共卫生相关性：该项目将调查潜咽心脏骤停后一种新的脑损伤机制。我们将使用模仿溺水等机制的小儿心脏骤停的啮齿动物模型。该项目有可能确定患有心脏骤停儿童的脑损伤疗法。