NEUROTROPHIC FACTOR DEPRIVATION AND NEURONAL CELL DEATH

神经营养因子剥夺和神经元细胞死亡

• 批准号: 8997532
• 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
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8997532
• 关键词: Ablation; Adverse effects; Amyloid; Animals; Apical; Apoptotic; Binding; Biological Models; Buffers; CASP8 gene; CDK4 gene; Caspase; Cell Culture System; Cell Cycle; Cells; Cessation of life; Chemicals; Complex; Cyclin-Dependent Kinases; DNA; Data; Development; Dissociation; E2F transcription factors; Elements; Environment; Event; Family member; Figs - dietary; Generations; Genes; Genetic; Genetic Transcription; Grant; Health; Knowledge; Lead; Learning; 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; response; stroke treatment; success; therapy development; transcription factor

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（由申请人提供）：该项目的整理目的是发现控制发育和病理神经元死亡的共同机制，并应用这些知识来制定中风，创伤和神经退行性疾病的治疗方法。拟议的研究将重点介绍该赠款深入研究的“凋亡细胞周期途径”，该赠款在各种发育和病理神经元死亡范式中起着必要的作用。在此途径中，依赖细胞周期蛋白依赖性激酶-4（CDK4）在响应凋亡刺激的神经元中激活。这是转弯的磷酸化RB口袋蛋白家族成员，导致它们与E2F转录因子与基因抑制复合物分离。 RB-E2F抑制剂复合物的解离会导致抑制和诱导MYB转录因子，这些因子结合并激活了包括BIM在内的凋亡蛋白的启动子。 BIM的诱导促进线粒体蛋白的释放和胱天蛋白酶的激活，导致神经元死亡。该提案的重点是凋亡刺激激活CDK4，尤其是CDC25A磷酸酶的机制。在细胞周期期间，CDC25A通过去除抑制性磷酸组来激活CDK4。我们将评估以下假设：CDC25A活性通过神经元中的凋亡刺激升高，这是触发凋亡细胞周期途径的根尖事件。初步支持数据包括发现CDC25A蛋白和转录本通过几种不同的凋亡刺激升高，并且CDC25A的敲低或化学抑制是神经保护性的。有两个具体的目标。 1）。在体外模型中测试Cdc25a在 发育和病理神经元死亡，并剖析其参与其中的凋亡细胞周期级联的上游元素。这将涉及多种细胞邪教系统和发育（NGF剥夺）和病理（AD，PD）神经元死亡的模型。我们将探索a）cdc25a在神经元死亡中所需的作用在我们的各种模型中，b）Cdc25a通过凋亡刺激调节的程度，c）Cdc25a下游的死亡级联成分，d）cdc25a的表达和活动是对这些刺激性刺激的上游机制。我们将特别热衷于识别涉及CDC25A的进料前卫死亡回路。 2）。为了测试体内发育神经元死亡所必需的CDC25A的假设。使用上颈神经节中发育神经元死亡的范式，我们将询问a）a）在垂死的神经元中诱导cdc25a水平是否诱导，b）在此类神经元中选择的下游细胞周期途径成分在此类神经元中共聚，c）在生物学上溶解的化学cdc25a抑制了这种神经元是否抑制了这种神经元的抑制作用。 cdc25a在交感神经节中。当前的发现表明，CDC25A是一个可药物的靶标，其体内抑制作用几乎没有副作用。因此，当前目标的成功具有明显的潜力，可以导致病理神经元死亡的疗法发展。