Exploring the Regenerative Capacity of Neurons in the Axolotl Brain.

探索蝾螈大脑中神经元的再生能力。

• 批准号: 8880895
• 负责人: Ryoji Amamoto
• 金额: $ 3.06万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8880895
• 关键词: Adult; Affect; Ambystoma; Amphibia; Biological; Biological Models; Brain; Bromodeoxyuridine; Cell physiology; Cells; Cerebral cortex; Clinical; Collaborations; Coupling; Cues; Development; Disease; Dorsal; Employee Strikes; Environment; Event; Exhibits; Failure; Gene Expression; Gene Expression Profile; Genome; Goals; Heart; Human; Immunofluorescence Immunologic; In Situ Hybridization; Injection of therapeutic agent; Injury; Institutes; Investigation; Knowledge; Limb structure; Mammals; Maps; Mental disorders; Messenger RNA; Methods; Modeling; Molecular; Natural regeneration; Nature; Nerve Regeneration; Neuraxis; Neurodegenerative Disorders; Neuronal Injury; Neurons; Organ; Organism; Pathway interactions; Phenotype; Process; Proliferating; RNA; Reading; Research; Resources; Salamander; Spinal; Spinal Cord; Stem cells; Stereotyping; Symptoms; System; Telencephalon; Time; Tissues; Transcript; Translating; Viral; Work; Xenopus; Zebrafish; adult stem cell; animal care; animal facility; blastema; brain repair; cell type; excitatory neuron; expectation; injured; interest; multidisciplinary; nerve stem cell; nervous system disorder; network architecture; neurogenesis; neuron loss; neuronal circuitry; novel therapeutics; nuclear reprogramming; progenitor; public health relevance; regenerative; repaired; research study; tool; transcriptome sequencing; water flow

DESCRIPTION (provided by applicant): Neurodegenerative disorders are characterized by a selective loss of neuronal subtypes that is often irreversible due to the failure of the adult huma brain to generate new neurons. To date, several options to ameliorate some of the symptoms exist, but none of these treatments successfully replace the lost neurons in humans. Thus, new avenues for brain repair are necessary. A method to replenish lost cells by giving rise to new neurons from adult stem cells or from existing neurons could potentially ameliorate the degenerative phenotype. While most mammalian neurons do not readily regenerate or reprogram without external manipulation, several species of salamanders naturally exhibit these feats. The axolotl is one such species with an increasing array of experimental tools. Intriguingly, recent studies have demonstrated that the various axolotl organs with regenerative potential - limb, spinal cord, heart - undergo natural reprogramming in order to replace lost tissue. Though the general mechanism is still unclear, this coupling of regeneration and reprogramming seem to be necessary for the regenerative potential of various organs in the axolotl. The axolotl brain is another organ with great regenerative ability. One-third of the telencephalon can be completely removed and the brain will repopulate the lost tissue within a few months with new neurons. However, the research of axolotl brain regeneration has only been performed before the 1960's when molecular and cellular biological tools were limited. Broadly, the goal of this proposal is to understand the regenerative process of the axolotl brain. Three specific questions drive this goal: 1) Do the specific neuronal subtypes and their respective circuits reconstruct with fidelity upon injury? 2) Where do the new neurons come from? Is it possible that existing neurons dedifferentiate to form a blastema, which subsequently differentiates into new neurons? 3) What molecular changes are associated with the regenerative process? Answering these questions would not only reveal the mechanism of brain regeneration in the axolotl, but it also may give clues to what molecules may be used to induce neurogenesis and nuclear reprogramming in an adult human brain. The combination of the lab of Dr. Paola Arlotta and the surrounding labs and institutes provide the necessary tools to answer these questions. The methods of completing the goal include immunofluorescence, in situ hybridization, RNA-seq, retrograde tracing, viral injection, and BrdU birthdating. The animal facility has the capacity to hold over one hundred axolotls in a free-flowing water system and a dedicated animal care team. These resources and tools that were unavailable fifty years ago will greatly facilitate the understanding of the brain regeneration process in the axolotl as well as th means to translate the regenerative process to a mammalian system and eventually towards therapy in humans.

描述（由申请人提供）：神经退行性疾病的特征在于神经元亚型的选择性丧失，由于成年人脑不能产生新的神经元，这种丧失通常是不可逆的。到目前为止，有几种方法可以改善一些症状，但这些治疗方法都没有成功地取代人类失去的神经元。因此，需要新的大脑修复途径。一种通过从成体干细胞或现有神经元产生新神经元来补充丢失细胞的方法可能会改善退行性表型。虽然大多数哺乳动物的神经元在没有外部操纵的情况下不容易再生或重新编程，但有几种蝾螈自然地表现出这些壮举。美西蝾螈就是这样一个物种，拥有越来越多的实验工具。有趣的是，最近的研究表明，各种具有再生潜力的蝾螈器官-肢体，脊髓，心脏-进行自然重编程，以取代失去的组织。虽然一般的机制还不清楚，这种再生和重编程的耦合似乎是必要的各种器官的再生潜力的蝾螈。美西蝾螈的大脑是另一个具有强大再生能力的器官。端脑的三分之一可以被完全切除，大脑将在几个月内用新的神经元重新填充失去的组织。然而，蝾螈脑再生的研究仅在20世纪60年代之前进行，当时分子和细胞生物学工具有限。从广义上讲，这项提案的目标是了解美西蝾螈大脑的再生过程。三个具体的问题驱动这一目标：1）特定的神经元亚型和它们各自的回路在损伤后是否重建逼真？2)新的神经元从何而来？有没有可能现有的神经元去分化形成芽基，芽基随后分化成新的神经元？3)什么样的分子变化与再生过程有关？解决这些问题不仅可以揭示美西蝾螈大脑再生的机制，而且还可以为成年人大脑中诱导神经发生和核重编程的分子提供线索。保拉·阿洛塔博士的实验室与周围的实验室和研究所的结合为回答这些问题提供了必要的工具。完成这一目标的方法包括免疫荧光、原位杂交、RNA-seq、逆行追踪、病毒注射和BrdU诞生。动物设施有能力在自由流动的水系统和专门的动物护理团队中容纳100多只美西蝾螈。这些50年前不可用的资源和工具将极大地促进对美西螈大脑再生过程的理解，以及将再生过程转化为哺乳动物系统并最终用于人类治疗的方法。