Cyclooxygenase 2 and Ischemic Neuronal Injury

环氧合酶 2 与缺血性神经元损伤

• 批准号: 8292093
• 负责人: STEVEN H GRAHAM
• 金额: $ 32.48万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8292093
• 关键词: 26S proteasome; 9-deoxy-delta-9-prostaglandin D2; Address; Adverse effects; Alzheimer' s Disease; Amino Acids; Anoxia; Anti-Inflammatory Agents; Anti-inflammatory; Arachidonic Acids; Binding; Brain; Brain Hypoxia-Ischemia; Cell Death; Cerebral Ischemia; Cessation of life; Chimeric Proteins; Chronic; Coxibs; Cysteine; Data; Deubiquitinating Enzyme; Development; Dominant-Negative Mutation; Enzymes; Etiology; Funding; Genes; Glutathione; Human; Hydrolase; Hypoxia; In Vitro; Incidence; Injury; Ischemia; Ischemic Neuronal Injury; Isoprostanes; Lead; Ligase; Liquid Chromatography; Marketing; Mass Spectrum Analysis; Measures; Mediating; Metabolism; Methods; Modification; Monitor; Myocardial Ischemia; Neurodegenerative Disorders; Neurons; Parkinson Disease; Pathogenesis; Pathway interactions; Peptide Hydrolases; Performance; Peroxidases; Pharmaceutical Preparations; Predisposition; Production; Prostaglandin D2; Prostaglandin Production; Prostaglandin Receptor; Prostaglandin-Endoperoxide Synthase; Prostaglandins; Proteins; Rattus; Reaction; Receptor Inhibition; Rofecoxib; Role; Stress; Stroke; Structure; Testing; Toxic effect; Ubiquitin; acute stroke; adduct; base; covalent bond; cyclooxygenase 2; cyclopentenone; enzyme activity; in vivo; inhibitor/antagonist; injured; multicatalytic endopeptidase complex; mutant; neuron loss; neuronal survival; prostaglandin R2 D-isomerase; protective effect; protein aggregation; public health relevance

DESCRIPTION (provided by applicant): Secondary prostaglandin metabolites produced by activation of cyclooxygenase 2 (COX2) after ischemia such as the cyclopentenone prostaglandins (CyPGs) may produce neuronal cell death. In preliminary studies, the concentrations of the CyPGs 15-deoxy-D12,14-PGD2, 15-deoxy-D12,14-PGJ2, and 12-PGJ2 were dramatically increased in brain after temporary focal ischemia. CyPGs injure primary cultured neurons, increase accumulation of ubiquitinated proteins (Ub-proteins), and exacerbate hypoxic injury in vitro at concentrations similar to those found in vivo. CyPGs covalently modify the cysteine C220 of UCH-L1, the key deubiquitinating enzyme in brain, and inhibit its activity. The susceptibility of neurons to hypoxia is reduced by transduction of neurons with a TAT-HA-UCH-L1 fusion protein. Based on these and other data we hypothesize that concentrations of CyPGs are increased in brain after ischemia and that CyPGs exacerbate hypoxic ischemic injury by disrupting the neuronal ubiquitin proteosome pathway (UPP), including covalent bonding and inhibition of UCH-L1. The following specific aims are proposed: 1. Characterize the production and metabolism of CyPGs after cerebral ischemia in vivo. 2. Determine if CyPGs exacerbate hypoxic injury and disrupt the UPP in primary neuronal culture in vitro. 3. Determine the role of inhibition of UCH-L1 activity and other components of the UPP by CyPGs in hypoxic ischemic injury. Accumulation of Ub-proteins and protein aggregation are important etiologies of delayed neuronal death in ischemia and neurodegenerative diseases. These studies aim to elucidate a new understanding of an important mechanism that results in accumulation of Ub-proteins and ER stress induced after ischemia. These findings may be relevant to the pathogenesis of stroke and neurodegenerative diseases such as Parkinson's and Alzheimer's disease. PUBLIC HEALTH RELEVANCE: The development of selective cyclooxygenase 2 (COX2) inhibitors as non-steroidal anti-inflammatory drugs raised hopes that these drugs could be useful in the treatment of stroke; however, chronic treatment with selective COX2 inhibitors such as Vioxx increased the incidence of myocardial ischemia and stroke in human trials. These undesirable effects of COX2 inhibitors have resulted in many of the drugs being withdrawn from the US market and tempered enthusiasm for any trials of these agents for acute stroke treatment. The current project aims to identify a downstream mechanism by which COX2 activity injures neurons which could lead to new treatments for stroke and neurodegenerative diseases.

描述（申请人提供）：缺血后环加氧酶 2 (COX2) 激活产生的次级前列腺素代谢物，例如环戊烯酮前列腺素 (CyPG)，可能会导致神经元细胞死亡。在初步研究中，短暂局灶性缺血后大脑中 CyPG 15-脱氧-D12、14-PGD2、15-脱氧-D12、14-PGJ2 和 12-PGJ2 的浓度显着增加。 CyPG 会损伤原代培养的神经元，增加泛素化蛋白（Ub 蛋白）的积累，并在体外以与体内相似的浓度加剧缺氧损伤。 CyPGs 共价修饰 UCH-L1（大脑中关键的去泛素化酶）的半胱氨酸 C220，并抑制其活性。通过使用 TAT-HA-UCH-L1 融合蛋白转导神经元，可以降低神经元对缺氧的敏感性。 基于这些和其他数据，我们假设缺血后大脑中 CyPG 的浓度增加，并且 CyPG 通过破坏神经元泛素蛋白体途径 (UPP)（包括共价键合和 UCH-L1 的抑制）来加剧缺氧缺血性损伤。 提出以下具体目标： 1.表征体内脑缺血后CyPGs的产生和代谢。 2. 确定 CyPG 是否会加剧缺氧损伤并破坏体外原代神经元培养物中的 UPP。 3.确定CyPGs抑制UCH-L1活性和UPP其他成分在缺氧缺血性损伤中的作用。 Ub 蛋白的积累和蛋白聚集是缺血和神经退行性疾病中迟发性神经元死亡的重要病因。这些研究旨在阐明导致缺血后 Ub 蛋白积累和内质网应激的重要机制的新认识。这些发现可能与中风和神经退行性疾病（如帕金森病和阿尔茨海默病）的发病机制有关。 公共健康相关性：选择性环氧合酶 2 (COX2) 抑制剂作为非甾体类抗炎药的开发使人们希望这些药物可用于治疗中风；然而，在人体试验中，长期使用选择性 COX2 抑制剂（如万络）治疗会增加心肌缺血和中风的发生率。 COX2 抑制剂的这些不良反应已导致许多药物从美国市场撤出，并削弱了对这些药物用于急性中风治疗的任何试验的热情。当前的项目旨在确定 COX2 活性损伤神经元的下游机制，从而可能为中风和神经退行性疾病带来新的治疗方法。