Neurotrophic Factor Deprivation and Neuronal Cell Death

描述(申请人提供)：这里的长期目标是了解神经元在正常发育过程中死亡的分子机制，以及对损伤和疾病的反应。这些信息不仅将提供对神经系统形成中的基本事件的深刻洞察，而且还可能导致发现治疗方法，以阻止脑和脊髓损伤、中风和神经退行性疾病等情况下的神经元死亡。这个项目的具体目标是基于这样一个发现，即神经元细胞死亡通常需要死亡相关蛋白的转录依赖合成。拟议的研究将集中在两条转录途径上，这两条途径与广泛的凋亡刺激引起的神经元死亡有关，并且在目前的支持期内一直是研究的主题和取得实质性进展。它们是：1)神经元细胞周期途径，其特征是不适当地激活细胞周期蛋白依赖性蛋白激酶，从而导致通常被转录因子E2F抑制的死亡相关基因的下调。细胞培养研究将评估细胞凋亡刺激触发这一途径的机制，重点是细胞周期蛋白依赖性激酶4和细胞周期蛋白D1的调节。此外，实验将确定E2F调节的转录因子B-和c-myb在死亡中的具体作用，以及死亡相关蛋白BIM受细胞周期途径调控的机制。最后，基因图谱方法(SAGE和基因芯片)将被用来确定受该途径调控的特定死亡相关基因2)神经元凋亡的JNK/cJun途径，其特征是一系列蛋白激酶的激活，最终导致磷酸化和转录因子c-jun的激活。研究将集中在表征支架蛋白POSH在该途径中的作用，并使用基因图谱技术来识别该途径调控的那些死亡相关基因。

DESCRIPTION (provided by applicant): The long-term objective here is to understand the molecular mechanisms by which neurons die during normal development and in response to injury and disease. Such information will not only provide deep insight about a fundamental event in nervous system formation, but also potentially lead to discovery of therapeutic approaches to block neuron death in circumstances such as brain and spinal cord injuries, stroke and neurodegenerative disorders. The specific aims of this project are based on the finding that neuronal cell death generally requires transcription-dependent synthesis of death-associated proteins.The proposed studies will focus on two transcriptional pathways that are causally involved in neuronal death evoked by a wide range of apoptotic stimuli and that have been the subject of study and substantial progress during the present period of support. These are: 1) The neuronal apoptotic cell cycle pathway which is characterized by inappropriate activation of cyclin-dependent kinases that in turn leads to de-repression of death-associated genes that are normally repressed by the transcription factor E2F.Cell culture studies will evaluate the mechanisms by which this pathway is triggered by apoptotic stimuli, with emphasis on regulation of cyclin-dependent kinase 4 and cyclin D1. In addition, experiments will define the specific roles of the E2F-regulated transcription factors B- and c-myb in death as well as the mechanism by which the death-associated protein BIM is regulated by the cell cycle pathway. Finally, gene profiling methods (SAGE and gene microarrays) will be used to identify specific death-associated genes regulated by this pathway 2) The neuronal apoptotic JNK/cJun pathway which is characterized by activation of a chain of protein kinases that culminates in phosphorylation and activation of the transcription factor c-Jun. Studies will focus on characterizing the role of the scaffold protein POSH in this pathway and on using gene profiling technology to identify those death associated genes that this pathway regulates.