The genetic mechanisms underlying the regenerative potential of ensheathing glial cells in Drosophila

果蝇鞘神经胶质细胞再生潜力的遗传机制

• 批准号: BB/L008343/1
• 负责人: Alicia Hidalgo
• 金额: $ 52.54万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FL008343%2F1
• 关键词: genetic; mechanisms; underlying; regenerative; potential

The central nervous system (CNS) does not regenerate after damage. Thus, spinal cord and brain damage (e.g. injury, stroke, multiple sclerosis) and neurodegeneration (e.g. Alzheimer's and Parkinson's diseases) result in devastating permanent disability. However, cells can accommodate changes in development and throughout normal life (e.g. during learning) to maintain normal function and behaviour, and regeneration after injury in animals also reveals that cells have a natural ability to sense and restore normal organism integrity. Understanding how cells 'know' how to achieve this and why they cannot in the CNS, is a great goal of biology and neuroscience. The glial cells that ensheath CNS axons respond to damage by proliferating, leading to axonal re-enwrapment and partial functional recovery of behavior. This glial regenerative response (GRR) is limited, but it is found across species, from flies to humans, suggesting that there is a natural, genetic mechanism of CNS repair. If we could understand this mechanism, we would be able to manipulate glial cells to promote repair. In mammals, oligodendrocyte progenitor cells (OPCs) have the greatest potential to induce regeneration in the damaged CNS and transplantation of stem or OPCs to the lesion site is the most promising therapeutic approach to CNS damage. However, the current scarce knowledge of how transplanted cells behave prevents a guarantee of repair or of avoidance of cancer. Most critically, what controls the differentiation of glial cells enabling axonal re-enwrapment and how might they influence neuronal regeneration or repair, are unknown. The fruit-fly Drosophila is a very powerful model organism to identify gene networks and test gene function in vivo, and it is successfully used to investigate responses to CNS injury, regeneration and repair. This led to the discovery of genetic mechanisms that induce glial proliferation, cell debris clearance, and axonal and dendritic regeneration. Genes discovered in fruit-flies are then tested in mammals, expediting research, and minimizing the use of protected animals.With BBSRC funding, we recently discovered a gene network controlling the Glial Regenerative Response (GRR) in Drosophila. This involves the genes encoding Prospero (Pros, a transcription factor that inhibits proliferation and promotes differentiation), Notch and NFkB (two cell cycle activators). Together, they form a homeostatic mechanism that balances glial cell number and differentiation control, enabling enwrapment whilst preventing tumours. Upon CNS injury, this gene network activates the glia to clear up cell debris, triggers their proliferation restoring cell number and enables axonal re-enwrapment. Manipulating Notch and Pros levels is sufficient to induce glial regeneration and promote axonal neuropile repair. We have tested this gene network in the mouse, and found that the pros homologue Prox1 is present in mammalian NG2-positive OPCs. This indicates that the GRR gene network is evolutionarily conserved. It is key to find out what genes are regulated by Pros to promote glial differentiation and enable glial and neuronal regeneration or repair. We aim to discover and investigate the functions of these genes. (1) We will select 5 out of 39 candidate genes regulated by Pros with potential functions in the GRR, including kon-tiki (kon), the Drosophila homologue of NG2. (2) We will analyse the functions of kon and four other genes in the glial responses to injury, and test their link to the GRR gene network. (3) We will investigate whether these genes can influence neuronal regeneration and/or repair.The outcome will be the discovery of molecular genetic mechanisms underlying glial differentiation and/or neuronal regeneration. In future projects, we will test our discoveries in mice, thus implementing the 3Rs policy (Refinement, Reduction, Replacement) using flies to speed up research for the improvement of human wellbeing and health.

中枢神经系统（CNS）在受损后不能再生。因此，脊髓和脑损伤（例如损伤、中风、多发性硬化）和神经变性（例如阿尔茨海默病和帕金森病）导致毁灭性的永久残疾。然而，细胞可以适应发育和整个正常生活（例如在学习期间）的变化，以维持正常的功能和行为，动物受伤后的再生也表明细胞具有感知和恢复正常生物体完整性的天然能力。了解细胞如何“知道”如何实现这一点，以及为什么它们不能在中枢神经系统中实现这一点，是生物学和神经科学的一个伟大目标。包裹CNS轴突的神经胶质细胞通过增殖对损伤作出反应，导致轴突重新包裹和行为的部分功能恢复。这种神经胶质再生反应（GRR）是有限的，但它在不同物种中发现，从苍蝇到人类，这表明CNS修复有一种天然的遗传机制。如果我们能够理解这种机制，我们就能够操纵神经胶质细胞来促进修复。在哺乳动物中，少突胶质细胞祖细胞（OPCs）具有最大的诱导受损CNS再生的潜力，并且干细胞或OPCs向损伤部位的移植是CNS损伤的最有希望的治疗方法。然而，目前缺乏关于移植细胞如何表现的知识，这阻碍了修复或避免癌症的保证。最关键的是，是什么控制了神经胶质细胞的分化，使轴突重新包裹，以及它们如何影响神经元的再生或修复，是未知的。果蝇是一个非常强大的模式生物，以确定基因网络和测试基因的功能在体内，它被成功地用于研究对中枢神经系统损伤，再生和修复的反应。这导致了诱导神经胶质细胞增殖、细胞碎片清除以及轴突和树突再生的遗传机制的发现。在果蝇中发现的基因随后在哺乳动物中进行测试，加快研究，并最大限度地减少保护动物的使用。在BBSRC的资助下，我们最近发现了一个控制果蝇神经胶质再生反应（GRR）的基因网络。这涉及编码Prospero（Pros，一种抑制增殖和促进分化的转录因子）、Notch和NFkB（两种细胞周期激活因子）的基因。它们共同形成了一种平衡神经胶质细胞数量和分化控制的稳态机制，从而在防止肿瘤的同时实现包裹。在CNS损伤时，该基因网络激活神经胶质细胞以清除细胞碎片，触发它们的增殖以恢复细胞数量并使轴突重新包裹。操纵Notch和Pros水平足以诱导神经胶质再生并促进轴突神经桩修复。我们已经在小鼠中测试了这个基因网络，发现prox同源物Prox 1存在于哺乳动物NG 2阳性OPC中。这表明GRR基因网络在进化上是保守的。找出Pros调控哪些基因以促进胶质细胞分化并使胶质细胞和神经元再生或修复是关键。我们的目标是发现和研究这些基因的功能。(1)我们将从39个受Pros调控的候选基因中选择5个在GRR中具有潜在功能的基因，包括NG 2的果蝇同源物kon-tiki（kon）。(2)我们将分析kon和其他四个基因在神经胶质对损伤的反应中的功能，并测试它们与GRR基因网络的联系。(3)我们将研究这些基因是否能影响神经元的再生和/或修复，其结果将是发现神经胶质细胞分化和/或神经元再生的分子遗传机制。在未来的项目中，我们将在小鼠中测试我们的发现，从而利用苍蝇实施3R政策（改进，减少，替代），以加快改善人类福祉和健康的研究。

项目成果

Regenerative neurogenic response from glia requires insulin driven neuron-glia communication

神经胶质细胞的再生神经反应需要胰岛素驱动的神经元-神经胶质细胞通讯

• DOI: 10.1101/721498
• 发表时间: 2019
• 作者: Harrison N

Prox1 Inhibits Proliferation and Is Required for Differentiation of the Oligodendrocyte Cell Lineage in the Mouse.

• DOI: 10.1371/journal.pone.0145334
• 发表时间: 2015
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Kato K;Konno D;Berry M;Matsuzaki F;Logan A;Hidalgo A
• 通讯作者: Hidalgo A

Go and stop signals for glial regeneration.

• DOI: 10.1016/j.conb.2017.10.011
• 发表时间: 2017-12
• 期刊: Current opinion in neurobiology
• 影响因子: 5.7
• 作者: Hidalgo A;Logan A
• 通讯作者: Logan A

Regenerative neurogenic response from glia requires insulin-driven neuron-glia communication.

• DOI: 10.7554/elife.58756
• 发表时间: 2021-02-02
• 期刊: eLife
• 影响因子: 7.7
• 作者: Harrison NJ;Connolly E;Gascón Gubieda A;Yang Z;Altenhein B;Losada Perez M;Moreira M;Sun J;Hidalgo A
• 通讯作者: Hidalgo A

Three-tier regulation of cell number plasticity by neurotrophins and Tolls in Drosophila.

• DOI: 10.1083/jcb.201607098
• 发表时间: 2017-05-01
• 期刊: The Journal of cell biology
• 作者: Foldi I;Anthoney N;Harrison N;Gangloff M;Verstak B;Nallasivan MP;AlAhmed S;Zhu B;Phizacklea M;Losada-Perez M;Moreira M;Gay NJ;Hidalgo A
• 通讯作者: Hidalgo A