C. elegans model for mammalian lesion-conditioned axon regeneration

描述（由申请人提供）：中枢神经系统（CNS）损伤每年困扰美国数百万人，缺乏有效的治疗方法。在这种损伤后恢复失去的功能的基本障碍是CNS再生弱。神经治疗学中最令人兴奋的发现之一是，如果在其外周感觉轴突上进行条件性损伤，则哺乳动物神经元可以强烈地再生其中央轴突进入和超出损伤部位。确定损伤调节中涉及的通路的关键组分将代表成功治疗CNS损伤的关键一步。哺乳动物系统的遗传操作的相对棘手性阻碍了对损伤调节的理解，但快速突破可能会导致在一个更简单的，遗传上易于处理的生物体损伤调节建模。小蛔虫C.秀丽线虫是一种非常有用的模式生物，具有无与伦比的遗传操纵能力。90年代末，C. elegans的研究人员注意到，一些神经元的电活动因突变而沉默，这些神经元长出了异位轴突。利用先进的激光手术技术，在完整的成年C。elegans中，我们观察到在这些相同的感觉神经元中强烈的损伤条件作用。最近发表的数据暗示在哺乳动物损伤条件反射中抑制电活动，以及我们的再生实验和以前关于C. elegans的研究表明，所有这些过程都是高度相关的，并共享遗传途径。本研究的目的是建立C. elegans作为哺乳动物损伤调节的遗传易处理模型。目的1的实验将进一步证明和表征刺激异位生长的神经元活性的减少和我们在C.优雅预期结果将与轴突再生的活动减少相关，并进一步确定异位生长的活动的作用。目的2的实验寻求开发正向筛选以鉴定介导异位轴突生长和损伤条件再生的基因。筛选将确定新的基因，抑制异位轴突生长和轴突再生在C。在高等动物中，同源哺乳动物基因介导损伤调节。通过开发一种遗传上易于处理的损伤调节模型，这些研究将为加速和变革性研究奠定基础，这些研究具有巨大的潜力来阐明这一非凡的再生途径的关键组成部分。所获得的知识将提出新的治疗途径，通过利用神经系统的内在再生能力来治疗CNS损伤。 公共卫生相关性：识别参与损伤调节的途径的关键组成部分，刺激中枢神经系统的强烈再生，是成功治疗脊髓损伤的关键一步。出于我们的初步研究结果，拟议的研究旨在建立线虫线虫作为一个遗传上易于处理的模型系统，用于研究病变条件反射。因此，它将有助于在这些非凡的通路中发现新的遗传和分子成分，为利用神经系统内在再生能力的疗法铺平道路。

DESCRIPTION (provided by applicant): Injuries to the central nervous system (CNS) afflict millions of people in the United States each year and lack an effective therapy. A fundamental barrier to recovering lost function after such injuries is weak CNS regeneration. One of the most exciting discoveries in neurotherapeutics is that mammalian neurons can strongly regenerate their central axons into and beyond an injury site if a conditioning lesion is made on their peripheral sensory axons. Identifying critical components of the pathways involved in lesion conditioning would represent a key step toward successfully treating CNS injuries. The relative intractability of mammalian systems to genetic manipulation has hampered progress toward understanding lesion conditioning, but rapid breakthroughs could result from modeling lesion conditioning in a simpler, genetically-tractable organism. The small roundworm C. elegans is an extremely useful model organism with unparalleled genetic manipulability. In the late 1990s C. elegans researchers noted ectopic axons outgrowing from several neurons whose electrical activity was silenced by mutation. Using advanced laser surgery techniques to dissect individual neurons within intact adult C. elegans, we observe a strong lesion conditioning effect in these same sensory neurons. Recently-published data implicating suppression of electrical activity in mammalian lesion conditioning, as well as similarities between our regeneration experiments and previous studies on ectopic outgrowth in C. elegans, indicate that all these processes are highly related and share genetic pathways. The goal of the proposed research is to establish ectopic outgrowth in C. elegans as a genetically tractable model for mammalian lesion conditioning. Experiments for aim 1 will further demonstrate and characterize the reduction of neuronal activity that stimulates ectopic outgrowth and the lesion conditioning effect we observe in C. elegans. Results are expected to correlate reduced activity with axon regeneration and further ascertain the role of activity in ectopic outgrowth. Experiments for aim 2 seek to develop a forward screen to identify genes mediating ectopic axon outgrowth and lesion conditioned regeneration. The screen will identify novel genes that suppress both ectopic axon outgrowth and axon regeneration in C. elegans, with homologous mammalian genes mediating lesion conditioning in higher animals. By developing a genetically tractable model for lesion conditioning, these studies will lay the foundation for expedited and transformative research that has tremendous potential to illuminate critical components of this remarkable regeneration pathway. The knowledge gained will suggest new therapeutic avenues for treating CNS injuries by exploiting the nervous system's intrinsic regenerative capability. PUBLIC HEALTH RELEVANCE: Identifying critical components of the pathways involved in lesion conditioning, which stimulates strong regeneration in the central nervous system, represents a key step toward successfully treating spinal cord injuries. Motivated by our preliminary findings, the proposed research aims to establish the roundworm Caenorhabditis elegans as a genetically tractable model system for the study of lesion conditioning. As such, it will facilitate the discovery of novel genetic and molecular components within these remarkable pathways, paving the way for therapies that exploit the nervous system's intrinsic regenerative capability.