Regulation of neural stem cells by retinoic acid and Notch signalling in the regenerating axolotl spinal cord

只有少数几种脊椎动物具有再生脊髓的能力，其中最重要的是有尾两栖动物，如蝾螈和蝾螈，以及一些硬骨鱼。在“再生能力”物种中，这种能力背后的复杂过程在很大程度上仍然是未知的。我们建议使用墨西哥蝾螈，一种成熟的再生能力两栖动物，来研究脊髓再生是如何工作的。 基于我们以前的研究，我们计划研究在再生过程中协调细胞之间相互作用的两种通信途径：视黄酸（RA）和Notch途径。我们将通过使用基因修饰的“转基因”蝾螈幼虫，以确定和可视化的多个核受体的活动在脊髓细胞的室管膜神经胶质细胞（EG）神经干细胞的关键人口RA信号的细胞网站。我们将带来新开发的“光遗传学”方法，使我们能够使用光来调节在正常脊髓再生过程中不同时间发生在EG细胞中的通信事件。重要的是，我们的工作将是第一个在这个水平上研究一些细胞间通讯网络在脊髓再生过程中是如何协调的。 所有这些工作将由硕士和博士生进行，他们将接受脊髓研究前沿方法的宝贵培训。 通过我们的工作过程中，我们将开发新的研究工具，将与加拿大和国外的脊髓研究社区共享。 我们希望能有重要的新发现，开始解开导致这些物种再生能力的复杂信号通路，并阐明哺乳动物在进化过程中失去这种能力的原因。

The ability to regenerate a functional spinal cord is restricted to only a few vertebrate species, foremost among them tailed amphibians such as newts and salamanders, and some bony fish. The complex processes that underlie this ability in “regeneration-competent” species is still largely unknown. We are proposing to use the Mexican axolotl, a well-established regeneration-competent amphibian, to examine how spinal cord regeneration works. Based on our previous research, we plan to examine two communication pathways that coordinate interactions between cells during regeneration: the retinoic acid (RA) and Notch pathways. We will do this by using genetically modified “transgenic” axolotl larvae to identify and visualize the cellular sites of activity of multiple nuclear receptors for RA signaling in a key population of spinal cord cells the ependymoglial (EG) neural stem cells. We will bring to bear newly developed optogenetic' methods that will enable us to use light to regulate the communication events that occur in EG cells at various times during normal spinal cord regeneration. Importantly, our work will be the first to examine, at this level, how some intercellular communication networks are coordinated during spinal cord regeneration. All of this work will be performed by MSc and PhD students, who will receive valuable training in cutting edge methods in spinal cord research. Through the course of our work we will develop new research tools that will be shared with the spinal cord research community in Canada and abroad. We hope to make important new discoveries that can begin to unravel the complex signaling pathways that lead to regeneration competence in these species and which could shed light on why mammals have lost this ability during evolution.