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NEUROTROPHIC FACTOR DEPRIVATION AND NEURONAL CELL DEATH

神经营养因子剥夺和神经元细胞死亡

基本信息

批准号：
9205541
负责人：
LLOYD A GREENE
金额：
$ 47.17万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-12-01 至 2018-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9205541
关键词：
Ablation Adverse effects Amyloid Animals Apical Apoptotic Binding Biological Buffers CDC25A protein CDK4 gene Caspase Cell Culture System Cell Cycle Cells Cessation of life Chemicals Complex Cyclin A Cyclin-Dependent Kinases DNA Data Development Dissociation E2F transcription factors E2F1 gene Elements Environment Event Family member Generations Genes Genetic Genetic Transcription Grant Knowledge Lead Mediating Mitochondrial Proteins Modeling Nerve Degeneration Neurodegenerative Disorders Neurons Neuroprotective Agents Pathologic Pathway interactions Phosphoric Monoester Hydrolases Phosphorylation Play Protein Family Proteins Regulation Role Signal Pathway Signal Transduction Specificity Stimulus Stroke Structure of superior cervical ganglion Sympathetic Ganglia System Testing Therapeutic Therapeutic Intervention Transcript Trauma Work deprivation derepression feeding in vitro Model in vivo inhibitor/antagonist inorganic phosphate knock-down molecular targeted therapies neuron loss neurotrophic factor novel pro-apoptotic protein promoter protein activation public health relevance response stroke treatment success therapy development transcription factor

项目摘要

DESCRIPTION (provided by applicant): The over-arching aim of this project is to uncover shared mechanisms that govern developmental and pathologic neuron death and to apply this knowledge to formulate treatments for stroke, trauma and neurodegenerative disorders. The proposed studies will focus on the "apoptotic cell cycle pathway" studied in depth under this grant that plays a required role in a variety of developmental and pathological neuron death paradigms. In this pathway, the cyclin-dependent kinase-4 (Cdk4) is activated in neurons in response to apoptotic stimuli. This is turn phosphorylates Rb pocket protein family members causing them to dissociate from gene-repressor complexes with the E2F transcription factors. Dissociation of Rb-E2F repressor complexes leads to derepression and induction of Myb transcription factors that bind to and activate the promoter for apoptotic proteins including Bim. Induction of Bim promotes release of mitochondrial proteins and activation of caspases, resulting in neuron death. This proposal focuses on the mechanism by which apoptotic stimuli activate Cdk4 and in particular on the cdc25a phosphatase. During the cell cycle, cdc25a activates Cdk4 by removing an inhibitory phosphate group. We will assess the hypothesis that cdc25a activity is elevated by apoptotic stimuli in neurons and that this is an apical event in triggering the apoptotic cell cycle pathway. Preliminary supportive data include findings that cdc25a protein and transcripts are elevated in neuronal cells by several different apoptotic stimuli, and that knockdown or chemical inhibition of cdc25a is neuroprotective. There are two specific aims. 1). To test, in in vitro models, the hypothesis that cdc25a plays a proximal role in developmental and pathological neuron death and to dissect the up- and downstream elements of the apoptotic cell cycle cascade in which it partakes. This will involve a variety of cell cultue systems and models for developmental (NGF deprivation) and pathological (AD, PD) neuron death. We will explore a) the required role of cdc25a in neuron death in our various models, b) the extent of cdc25a regulation by apoptotic stimuli, c) the death cascade components that lie downstream of cdc25a, and d) the upstream mechanisms by which cdc25a expression and activity are regulated and how these are engaged by apoptotic stimuli. We will be particularly keen to identify feed-forward death loops involving cdc25a. 2). To test the hypothesis that cdc25a is required for developmental neuron death in vivo. Using the paradigm of developmental neuron death in superior cervical ganglia, we will query whether a) cdc25a levels are induced in dying neurons, b) selected downstream cell cycle pathway components are co-elevated in such neurons, c) biologically-tolerated chemical cdc25a inhibitors suppress neuron death in this system and d) whether such death is inhibited by selective genetic ablation of cdc25a in sympathetic ganglia. Current findings indicate that cdc25a is a druggable target whose in vivo inhibition has little side effects. Thus success of the current aims has a clear potential to lead to development of therapies for pathologic neuron death.

描述(申请人提供)：该项目的总体目标是揭示控制发育和病理性神经元死亡的共同机制，并将这一知识应用于制定中风、创伤和神经退行性疾病的治疗方案。建议的研究将集中在这项拨款下深入研究的“凋亡细胞周期途径”，该途径在各种发育和病理性神经元死亡范例中发挥着必要的作用。在这一途径中，细胞周期蛋白依赖性激酶-4(CDK4)在神经元中被激活，以响应细胞凋亡的刺激。这是依次磷酸化的RB口袋蛋白家族成员，使他们从与E2F转录因子的基因抑制复合体中解离。Rb-E2F阻遏物复合体的解离导致Myb转录因子的去抑制和诱导，Myb转录因子结合并激活包括Bim在内的凋亡蛋白的启动子。Bim的诱导促进了线粒体蛋白的释放和caspase的激活，导致神经元死亡。这项建议侧重于凋亡刺激激活CDK4的机制，特别是对CDC25a磷酸酶的激活。在细胞周期中，cdc25a通过去除抑制的磷酸基团来激活CDK4。我们将评估这一假说，即cdc25a活性因神经元中的凋亡刺激而升高，这是触发凋亡细胞周期途径的顶端事件。初步的支持性数据包括发现，几种不同的凋亡刺激使神经细胞中的cdc25a蛋白和转录本增加，并且cdc25a的敲除或化学抑制具有神经保护作用。有两个具体目标。1)。为了在体外模型中检验cdc25a在研究发育性和病理性神经元死亡，并剖析其所参与的凋亡细胞周期级联的上下游因素。这将涉及各种细胞培养系统和发育性(NGF剥夺)和病理性(AD，PD)神经元死亡的模型。我们将探索a)在我们的各种模型中cdc25a在神经元死亡中所需的角色，b)cdc25a受凋亡刺激调控的程度，c)位于cdc25a下游的死亡级联成分，以及d)cdc25a表达和活性被调控的上游机制以及这些机制是如何被凋亡刺激参与的。我们将特别热衷于识别涉及cdc25a的前馈死循环。2)。为了验证cdc25a是体内发育神经元死亡所必需的假设。利用颈上神经节发育性神经元死亡的范式，我们将质疑a)死亡神经元中cdc25a的水平是否被诱导，b)选定的下游细胞周期通路成分在这类神经元中是否共上调，c)生物耐受的化学物质cdc25a抑制剂抑制该系统中的神经元死亡，以及d)交感神经节中cdc25a的选择性基因消融是否抑制了这种死亡。目前的研究结果表明，cdc25a是一个药物靶点，其体内抑制作用几乎没有副作用。因此，当前目标的成功显然有可能导致病理性神经元死亡治疗的发展。