Development of a C. elegans model for axonal regeneration

描述（由申请人提供）：很少有研究利用遗传学和功能基因组学的力量来了解损伤后轴突再生的机制。我们已经开发了飞秒激光轴突切断术来切断完整的活C。优雅的动物。切断几个C. elegans细胞类型显示出稳健的再生长和功能恢复。我们已经表明，包括细胞类型，轴突切断的位置和生命阶段在内的几个因素可以调节轴突损伤后是否再生。保守的信号传导途径，包括环AMP信号传导和ephrin信号传导，调节轴突的再生生长。我们还发现了突触分支在调节轴突再生中的意想不到的作用。利用C.秀丽隐杆线虫有利于大规模筛选新的再生基因。一项试验性的筛选发现了几个促进或抑制再生生长的新基因。我们的三个具体目标建立在这些初步结果：首先，我们将剖析突触分支调节机械感觉神经元再生的机制。我们假设突触分支点包含一个分类区，它在损伤后调节膜和细胞器的交通。我们将分析再生所需的发动机和货物的运输，并将专门测试Liprin途径在促进再生中的作用。其次，我们将确定cAMP信号如何促进C。神经再生我们将测试cAMP或其效应物是否是再生所必需的。我们将研究轴突切断对体内cAMP动力学的影响。我们将测试一个假定的cAMP调节的转录因子，我们发现是必不可少的再生的作用。第三，我们将进行大规模的功能基因组筛选，以确定在再生轴突生长中发挥作用的新基因。将详细研究具有强促或抗再生作用的基因的机制。相关性：这项工作将产生一个简单的模型系统损伤后调节轴突再生的途径的系统性理解。控制轴突再生的保守机制的知识将允许它们在神经系统疾病和损伤的治疗中的操纵。公共卫生相关性：我们将分析线虫C神经再生的分子和遗传机制。优雅具体来说，我们将定义的作用，贩运在轴突分支点和环磷酸腺苷信号的功能。我们将进行大规模筛选，以发现参与神经元再生生长的新基因。这些结果将进一步加深我们对神经再生的理解，并有助于治疗神经系统的创伤和疾病。

DESCRIPTION (provided by applicant): Few studies have exploited the power of genetics and functional genomics to understand the mechanisms of regrowth of axons following injury. We have developed femtosecond laser axotomy to cut single axons in intact living C. elegans animals. Severed axons of several C. elegans cell types show robust regrowth and functional recovery. We have shown that several factors, including cell type, position of axotomy and life stage, can regulate whether axons regrow after injury. Conserved signaling pathways, including cyclic AMP signaling and ephrin signaling, regulate regenerative growth of axons. We also found an unexpected role for synaptic branches in regulating axon regrowth. The tractable genetic and genomic tools available in C. elegans facilitate large scale screens for new regeneration genes. A pilot screen has uncovered several new genes that promote or repress regenerative growth. Our three specific Aims build on these preliminary results: First, we will dissect the mechanism by which the synaptic branch regulates regeneration in mechanosensory neurons. We hypothesize that the synaptic branch point contains a sorting area that regulates membrane and organelle traffic after injury. We will analyze the transport of motors and cargoes required for regrowth and will specifically test the role of the Liprin pathway in promoting regrowth. Second we will define how cAMP signaling promotes C. elegans neuronal regeneration. We will test whether cAMP or its effectors are required for regrowth. We will examine the effects of axotomy on cAMP dynamics in vivo. We will test the role of a putative cAMP-regulated transcription factor that we have found is essential for regeneration. Third, we will perform a large scale functional genomic screen to identify new genes with roles in regenerative axon growth. The mechanisms of genes with strong pro- or anti-regeneration roles will be studied in detail. Relevance: This work will yield a systematic understanding of the pathways that regulate axon regeneration after injury in a simple model system. Knowledge of the conserved mechanisms controlling axon regeneration will allow their manipulation in therapies for nervous system disease and injury. PUBLIC HEALTH RELEVANCE: We will analyze the molecular and genetic mechanisms underlying nerve regeneration in the nematode C. elegans. Specifically, we will define the roles of trafficking at axonal branch points and the function of cyclic AMP signaling. We will perform a large scale screen to discover novel genes involved in regenerative growth of neurons. The results will further our understanding of nerve regrowth and will aid therapies for trauma and disease of the nervous system.