NEUROTROPHIC FACTOR DEPRIVATION AND NEURONAL CELL DEATH

描述：这项工作的总体目标是了解分子 哺乳动物神经元经历细胞凋亡死亡的途径。整体而言 假设神经细胞凋亡性死亡的途径由 多个相互关联的步骤，这些步骤的性质 取决于引发死亡的原因。主要关注点是 营养因子剥夺引起的细胞凋亡。另外两种方式 将考虑诱发细胞凋亡，以进行比较，暴露于 DNA损伤剂与耗竭细胞引起的氧化应激 超氧化物歧化酶1.将在大鼠PC12的培养中进行研究 细胞和交感神经元。提出的具体目标集中在两个方面 细胞凋亡途径的组成部分。这一假设将得到检验， 营养因子剥夺和DNA损伤引发的细胞凋亡(而不是 氧化应激)需要激活特定的细胞周期蛋白依赖性激酶， 增强Rb蛋白的磷酸化和激活E2F转录 各种因素。第二个目标侧重于caspase成员的作用。 半胱氨酸天冬氨酸酶家族作为神经细胞凋亡性死亡的执行者。 实验将确定死亡所需的每一个半胱氨酸酶 三种实验性的凋亡论范式，决定了caspase 在对细胞凋亡刺激的反应中被激活，并发现相对的 中的其他元素之间的位置 细胞凋亡途径。这一假说将被评估为神经元凋亡 由不同的原因引起的caspase家族成员的调节作用不同。

DESCRIPTION: The overall goal of this work is to understand the molecular pathways by which mammalian neurons undergo apoptotic death. The overall hypotheses are that the pathways of neuronal apoptotoic death are composed of multiple, causally-linked steps and that the nature of these steps depends on the initiating causes of death. The major focus will concern apoptosis evoked by trophic factor deprivation. Two additional means of evoking apoptosis will be considered for purposes of comparison, exposure to DNA damaging agents and induction of oxidative stress by depletion of superoxide dismutase 1. Studies will be performed in cultures of rat PC12 cells and sympathetic neurons. The proposed specific aims focus on two components of the apoptotic pathway. The hypothesis will be tested that apoptosis initiated by trophic factor deprivation and DNA damage (and not oxidative stress) requires activation of specific cyclin-dependent kinases, enhanced phosphorylation of Rb protein and activation of E2F transcription factors. The second aim focuses on the roles of members of the caspase family of cysteine aspartases as executors of neuronal apopototic death. Experiments will identify the caspases required for death in each of the three experimental apopotic paradigms, determine the means by which caspases are activated in response to apoptotic stimuli, and uncover the relative positions of the caspases to one another and to other elements in the apoptotic pathway. The hypothesis will be evaluated that neuronal apoptosis evoked by different causes is mediated by distinct caspase family members.