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）。异常的神经元凋亡也与神经元凋亡有关。 几种神经退行性疾病的发病机制和神经元的损失 中风或外伤后我们研究的模型系统， 神经上皮（OE），包含一个简单的，可接近的嗅觉受体组 神经元（ORN），每4-6周发生一次细胞凋亡， 成年因为OE有独特的能力， 神经元群体重复并重新建立功能连接， 因此保持嗅觉功能。由于其可访问性， 在体外和体内的实验操作中，OE是一个适合的模型 用于检查驱动分离的分子和细胞机制的系统， 但相关的神经发生和神经元凋亡的过程。总目标 是利用嗅觉系统来剖析 哺乳动物神经元经历凋亡性死亡的途径，重点是 蛋白酶的胱天蛋白酶家族的特定成员的作用。整体 假设神经元凋亡性死亡的途径由以下组成： 由不同的半胱天冬酶介导的多个因果联系的步骤， 这些步骤的时空性质取决于死亡的起始原因。 主要研究手术诱导的ORN同步凋亡， 与诱导ORN相比，去除ORN目标，嗅球 通过营养因子撤除（靶神经元的兴奋性毒性去除）引起的凋亡 NMDA）和过度刺激。我们已经证明了caspase 3 和9在ORN凋亡中起着重要作用，它们可以启动ORN的凋亡 轴突末端的通路。为了进一步确定其作用，在目标一中， 将研究导致成熟ORN中半胱天冬酶-3和-9活化的途径 在体内和目标二中，我们将重新建立和测试这些途径 在体外ORN凋亡过程中。在目标三中，我们研究了半胱天冬酶在以下方面的作用： 发育性ORN细胞凋亡，集中于半胱天冬酶3和9无效突变小鼠。在 第四，我们将测试抑制剂和腺病毒表达的方法，以防止 或延迟ORN凋亡，目的5，我们将产生OMP-Cre小鼠 为了应用条件敲除策略来检查 凋亡途径的调节仅在成熟的ORN群体中。

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.