The Role of Caspases in Olfactory neuron Apoptosis

描述：(申请人提供) 细胞凋亡在中枢神经系统的发育和衰老中起着至关重要的作用。 神经系统(CNS)。神经细胞的异常凋亡也与 几种神经退行性疾病和神经元丢失的发病机制 中风或创伤后的。我们研究的模型系统，嗅觉 神经上皮(OE)含有一组简单、可接近的嗅觉感受器 神经元(ON)，每隔4-6周经历一次细胞凋亡 成人期。因为OE具有独特的能力来重新生成其整个 重复神经元组合并重新建立功能连接， 因此，嗅觉功能得以保留。因为其可访问性 体外和体内的实验操作，OE是一个顺从的模型 用于检查分子和细胞机制的系统，这些机制驱动分离的、 但与此相关的是神经发生和神经元凋亡的过程。总目标 这个项目的目的是使用嗅觉系统来解剖分子 哺乳动物神经元经历凋亡性死亡的途径，重点是 S作用于caspase蛋白家族中的特定成员。整体而言 假设神经细胞凋亡死亡的途径由以下几个部分组成 由不同的半胱氨酸酶介导的多个因果联系的步骤，以及 这些步骤的时空性质取决于引发死亡的原因。 主要的焦点是研究手术诱导的同步性ORN细胞凋亡 切除ORN靶点、嗅球与诱发ORN的比较 营养因子撤除引起的细胞凋亡(靶神经元的兴奋性毒性去除 NMDA)和过度刺激。我们已经证明了caspase 3 和9在ORN细胞凋亡中起中心作用，它们可以启动细胞凋亡 轴突终末的通路。为了进一步定义他们的角色，在目标一中，我们 研究成熟ORN中导致caspase-3和-9激活的途径 在体内和目标2中，我们将重新建立和测试这些途径 在体外ORN细胞凋亡过程中。在第三个目标中，我们研究了caspase在 发育中的ORN细胞凋亡，集中在caspase3和9缺失突变小鼠。在……里面 目标四我们将测试抑制物和腺病毒表达方法来预防 或在体外延迟ORN的凋亡，在Aim 5中，我们将产生OMP-CRE小鼠 为了应用有条件的击倒策略来检查 仅在成熟的ORN人群中对细胞凋亡途径进行调控。

DESCRIPTION: (provided by applicant) Apoptosis plays a crucial role in both the development and aging of the central nervous system (CNS). Aberrant neuronal apoptosis has also been linked to the pathogenesis of several neurodegenerative diseases and in the loss of neurons following stroke or trauma. The model system we study, the olfactory neuroepithelium (OE), contains a simple, accessible group of Olfactory Receptor Neurons (ORNs), each of which undergo apoptosis every 4-6 weeks throughout adulthood. Because the OE has the unique ability to regenerate its entire neuronal population repeatedly and re-establish functional connectivity, olfactory function is thus retained. Because of its accessibility for experimental manipulation in vitro and in vivo, the OE is an amenable model system for examining molecular and cellular mechanisms that drive the separate, but related, processes of neurogenesis and neuronal apoptosis. The overall goal of this project is to use the olfactory system to dissect the molecular pathways by which mammalian neurons undergo apoptotic death, focussing on the role s of specific members of the caspase family of proteases. The overall hypotheses are that the pathways of neuronal apoptotic death are composed of multiple, causally-linked steps mediated by different caspases, and that the spatiotemporal nature of these steps depends on the initiating causes of death. The primary focus is to study synchronous ORN apoptosis induced by surgical removal of the ORN target, the olfactory bulb in comparison with inducing ORN apoptosis by trophic factor withdrawal (excitotoxic removal of target neurons with NMDA) and over-stimulation. We have already demonstrated that caspase 3 and 9 play central roles in ORN apoptosis and that they can initiate apoptotic pathways at the axon terminal. To define their role further, in Aim One we shall examine pathways leading to caspase -3 and -9 activation in mature ORN apoptosis in vivo and in Aim Two, we will re-establish and test these pathways during ORN apoptosis in vitro. In Aim Three we examine the role of caspases in developmental ORN apoptosis, focusing on caspase 3 and 9 null mutant mice. In Aim Four we will test inhibitor and adenoviral expression approaches to prevent or delay ORN apoptosis in vitro and in Aim 5, we will generate an OMP-Cre mouse for the purpose of applying a conditional knockout strategy to examine apoptotic pathway regulation only in the mature ORN population.