Mechanism of CREB dysregulation in Alzheimer brain

阿尔茨海默病大脑 CREB ​​失调的机制

• 批准号: 8803335
• 负责人: SUBBIAH PUGAZHENTHI
• 金额: --
• 依托单位: VA EASTERN COLORADO HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8803335
• 关键词: A Mouse; Adverse effects; Affect; Age-Years; Alzheimer' s Disease; Alzheimer' s disease risk; Anti-Inflammatory Agents; Astrocytes; Astrocytosis; BCL2 gene; Brain; Brain-Derived Neurotrophic Factor; Cells; ChIP-seq; Chronic; Clinical Trials; Coculture Techniques; Cognition; Complex; Conditioned Culture Media; Cyclic AMP-Responsive DNA-Binding Protein; Data; Deterioration; Disease; Distress; Down-Regulation; E1A-associated p300 protein; Elderly; Emetics; Environment; Epidemiologic Studies; Event; Free Radicals; Functional disorder; Gene Chips; Gene Expression; Gene Expression Profile; Gene Expression Profiling; Gene Transfer; Genes; Genetic Transcription; Growth Factor; Health; Healthcare Systems; Hippocampus (Brain); Human; Impaired cognition; In Vitro; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; JUN gene; Link; Mediating; Medical center; Memory; Methodology; Microglia; Minocycline; Modeling; Molecular; Mus; NF-kappa B; Nerve Degeneration; Neurons; Neurotoxins; Non-Steroidal Anti-Inflammatory Agents; Nuclear; Oxidative Stress; Pathology; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphorylation; Play; Population; Protein Family; Proteins; Protocols documentation; Reactive Oxygen Species; Role; Rolipram; Sampling; Signal Pathway; Signal Transduction; Signaling Pathway Gene; Site; Synapses; Testing; Therapeutic; Therapeutic Intervention; Transgenic Mice; Transgenic Organisms; Veterans; analog; base; cell type; cognitive function; cytokine; design; experience; in vivo; injured; laser capture microdissection; macrophage; mouse model; nerve stem cell; neurofibrillary tangle formation; neuroinflammation; neuronal survival; neurotoxic; neurotransmission; novel; pathogen; progressive neurodegeneration; promoter; protein expression; protein function; response; restoration; spatial relationship; synergism; transcription factor

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is characterized by cognitive dysfunction and progressive neurodegeneration. Hallmarks of AD pathology include accumulation of A¿-containing plaques, formation of neurofibrillary tangles and synaptic dysfunction. Microglia, the resident macrophages of the brain, play a protective role by reducing A¿ load. However, cytokines and free radicals released from hyperactivated microglia cause neuronal damage. Injured neurons facilitate their own demise by sending out distress signals to microglia. This proposal takes a close look at the molecular events in neurons exposed to activated microglia by in vitro and in vivo studies. Altered signaling pathways and orchestrated gene expression patterns in neurons are known to play significant roles in causing AD pathology. In this model, transcription factors provide a crucial link between signaling pathways and gene expression. Cyclic AMP response element binding protein (CREB), a nuclear transcription factor, enhances cognition, memory formation and neuronal survival. CREB is known to be downregulated in the AD brain. However, therapeutically targeting CREB is a challenge because of its broad spectrum actions. Transcription factors are directed to appropriate promoters in a context and cell-type dependent manner by upstream signals. We have characterized the growth factor-stimulated signaling pathways that activate CREB and the mechanism through which oxidative stress interferes with CREB function in cultured neurons. In a recent study with AD post-mortem samples and Alzheimer's transgenic mice, we identified the decrease of hippocampal CREB expression by A¿-generated oxidative stress as a late event. But the decrease in CREB content is preceded by persistent downregulation of CREB function. The following two critical findings from our preliminary studies suggest that inflammation, an early event in the progression of AD, interferes with CREB function. (i) CREB-regulated BDNF expression in human neuroprogenitor cell (NPC)- derived neurons was decreased by conditioned medium from A¿-activated human microglia. (ii) Restoration of CREB function protected neurons cocultured with A¿-activated microglia. Protective and neurodegenerative pathways of inflammation can be delineated at the transcriptional level. Inflammation-mediated CREB dysregulation takes place at the following sites: (i) Cytokines and reactive oxygen species decrease CREB phosphorylation/activation. (ii) Inflammation activates c-jun, STAT-1 and NF-?B, the transcriptions factors that compete with CREB for the limited pool of coactivators, CBP and p300. (iii) Inflammation can direct CREB to pathways other than those needed for neuronal function. (iv) Proteins produced in response to inflammation functionally antagonize CREB target proteins that promote neuronal survival. Our hypothesis is that the pathogenic component of chronic neuroinflammation, acting synergistically with oxidative stress, downregulates CREB-mediated transcription of neuroprotective genes in the AD brain. This hypothesis will be tested in human neuroprogenitor cell derived-neurons, cocultured with microglia and in a triple transgenic Alzheimer's mice using novel methodologies including laser capture microdissection, network motif-based analysis and design-based stereology with the following Specific Aims: Aim 1. To determine the mechanism of CREB downregulation in cultured human neuroprogenitor cell-derived neurons exposed to A¿-activated microglia and astrocytes. Aim 2. To identify neuronal CREB downregulation as a pathogenic component of neuroinflammation in triple transgenic Alzheimer's (3XTg-AD) mouse brain: Therapeutic strategies can target transcription factors and their network for profound beneficial effects. Our lab has 15 years of experience and the expertise to examine CREB function in the context of parallel activation of competing transcription factors during inflammation and oxidative stress.

描述（由申请人提供）： 阿尔茨海默氏病（AD）的特征是认知功能障碍和进行性神经变性。 AD病理学的标志包括含有A斑的斑块的积累，神经原纤维缠结的形成和突触功能障碍。小胶质细胞是大脑的巨噬细胞，通过减少A负载来发挥保护作用。然而，从多活化的小胶质细胞释放的细胞因子和自由基会导致神经元损伤。受伤的神经元通过向小胶质细胞发出遇险信号来促进自己的灭亡。该建议仔细研究了通过体外和体内研究暴露于活化小胶质细胞的神经元中的分子事件。已知神经元中的改变信号通路和精心策划的基因表达模式在引起AD病理学方面起着重要作用。在此模型中，转录因子在信号通路和基因表达之间提供了至关重要的联系。循环AMP反应元件结合蛋白（CREB）是一种核转录因子，增强了认知，记忆形成和神经元存活。已知CREB在AD大脑中被下调。但是，由于其广泛的范围动作，因此在治疗上靶向CREB是一个挑战。转录因子是在上游信号的上下文中针对适当的启动子的。我们已经表征了生长因子刺激的信号通路，该信号通路激活CREB以及氧化物应力在培养的神经元中干扰CREB功能的机制。在最近用AD验尸样品和阿尔茨海默氏症的转基因小鼠的一项研究中，我们确定了通过a生成的氧化物胁迫的海马CREB表达的下降，这是后期事件。但是，CREB含量的减少是在CREB功能的持续下调之前。我们初步研究的以下两个关键发现表明，炎症是AD进展的早期事件，会干扰CREB功能。 （i）在人神经元基因细胞（NPC）中受到CREB调节的BDNF表达 - 衍生的神经元通过a =活化的人类小胶质细胞的条件培养基降低。 （ii）CREB功能的恢复受保护的神经元与A研究小胶质细胞共培养的神经元。可以在转录水平上划定炎症的保护性和神经退行性途径。炎症介导的CREB失调在以下部位发生：（i）细胞因子和活性氧降低CREB磷酸化/激活。 （ii）炎症激活C-Jun，Stat-1和NF-？B，与CREB竞争有限的共激活因子CBP和P300的转录因子。 （iii）炎症可以将CREB引向神经元功能所需的途径。 （iv）响应炎症产生的蛋白质在功能上拮抗促进神经元存活的CREB靶蛋白。我们的假设是，慢性神经炎症的致病成分与氧化应激协同作用，下调了CREB介导的AD脑中神经保护基因的转录。该假设将在人类神经元素细胞衍生的神经元中进行测试，与小胶质细胞共培养，并使用新方法在三重转基因阿尔茨海默氏症小鼠中使用激光捕获的新方法，包括激光捕获微分解，基于网络基准的分析和基于设计的定型学，并具有以下特定目的：以下特定目的：以下特定目的。激活的小胶质细胞和星形胶质细胞。目的2。确定神经元CREB下调是三重转基因阿尔茨海默氏症（3xTG-AD）小鼠脑中神经炎症的致病成分：治疗策略可以靶向转录因子及其网络，从而产生深远的有益作用。我们的实验室有15年的经验和专业知识，可以在炎症和氧化应激期间平行激活竞争转录因子的情况下检查CREB功能。