In vivo reprogramming reactive astrocytes into functional neuorons by microRNA-124 in the injured spinal cord

项目总结： 脊髓损伤(Sci)是一种破坏性的神经系统疾病，常损害患者的日常功能。 在他们的一生中。治疗脊髓损伤的主要障碍之一是如何恢复失去的神经元功能。 尽管几十年的研究努力，目前的策略，包括干细胞移植，并没有产生结果 一种成功的临床疗法。因此，迫切需要开发治疗脊髓损伤的新技术。这 研究小组最近开发了一种创新的方法，将反应性星形胶质细胞重新编程为功能 注射表达单一神经转录因子的病毒颗粒原位修复脑损伤的神经元 将NeuroD1导入成年小鼠的大脑皮质(Guo等人，细胞干细胞，2014年最佳文章)。这项提议将 将这一尖端的体内重编程技术引入SCI。特别是，国际和平研究所建议将 通过强制表达神经元特异性microRNA将内源性反应性星形胶质细胞转化为功能神经元 (MiRNA)miR-124。目前的大多数体内重新编程研究，包括这个团队的研究，都是 通过使用表达神经性转录因子的病毒载体来完成；并通过在体内通过 MiRNAs还没有报道。 MiRNAs是一种小的非编码RNA，在神经发育和疾病中发挥着关键作用。这个 MiRNA的功能可能是强大的，因为一个miRNA可能通过独特的 碱基配对机制不完善。此外，它们的小尺寸(~22个核苷酸)使它们对 治疗应用，因为它们可以很容易地穿透组织并被靶细胞吸收。MIR-124播放 在神经发生、神经元分化和成熟中的关键作用，这使它成为理想的候选者 神经元重新编程。因此，在这项建议中，PI将检验强制表达的假设 MIR-124可以在损伤的脊髓中将反应性星形胶质细胞转化为功能神经元，并将其转化为 神经元可以整合到局部神经元回路中，促进脊髓损伤后功能的恢复。《少年派》 提出了两个具体目标：1)确定miR-124将反应性星形胶质细胞转化为神经元 2)确定miR-124转化神经元的功能整合及其对动物的影响 挫伤性脊髓损伤后的行为。在这里完成拟议的研究将显示miR-124介导的可行性 胶质细胞-神经元在体内的转化，为这种小RNA分子的治疗应用奠定了基础 作为一种未来的合成药物。此外，这一提议的成功可能会导致一部小说 治疗脊髓损伤以及其他神经疾病，如创伤性脑损伤(TBI)和 肌萎缩侧索硬化症(ALS)。

Project Summary: Spinal cord injury (SCI) is a devastating neurological disorder that often impairs the daily function of patients for their entire life. One of the major obstacles in treating SCI is how to restore the lost neuronal functions. Despite decades of research efforts, current strategies including stem cell transplantation have not resulted in a successful clinical therapy. Therefore, there is an urgent need to develop novel technology to treat SCI. This research team has recently developed an innovative approach to reprogram reactive astrocytes into functional neurons in situ for brain repair by injecting viral particles expressing a single neural transcription factor NeuroD1 into the adult mouse cortex (Guo et al., Cell Stem Cell, BEST of 2014 article). This proposal will introduce this cutting-edge in vivo reprogramming technology into SCI. In particular, the PI proposes to convert endogenous reactive astrocytes into functional neurons by forced expression of a neuronal specific microRNA (miRNA) miR-124. Most of current in vivo reprogramming studies including the one from this team have been done by using viral vectors expressing neurogenic transcription factors; and in vivo neuronal conversion by miRNAs has not been reported. MiRNAs are small non-coding RNAs that play pivotal roles during neural development and diseases. The miRNA function could be potent in that one miRNA may regulate many target genes through the unique imperfect base-pairing mechanism. Furthermore, their small size (~22 nucleotides) makes them attractive for therapeutic application since they may easily penetrate tissues and be taken up by target cells. MiR-124 plays critical roles in neurogenesis, neuronal differentiation and maturation, which makes it an ideal candidate for neuronal reprogramming. Therefore, in this proposal, the PI will test the hypothesis that forced expression of miR-124 can convert reactive astrocytes into functional neurons in the injured spinal cord, and that converted neurons can integrate into the local neuronal circuitry and promote functional recovery after SCI. The PI proposes two specific aims: 1) To determine conversion of reactive astrocytes into neurons by miR-124 after SCI; 2) To determine functional integration of miR-124-converted neurons and their effects on animal's behavior after contusive SCI. Completion of the proposed study here will show feasibility of miR-124-mediated glia-neuron conversion in vivo and lay out foundation for therapeutic application of this small RNA molecules as a synthetic drug in the future. In addition, the success of this proposal will potentially lead to a novel therapeutic treatment for SCI as well as other neurological diseases such as traumatic brain injury (TBI) and amyotrophic lateral sclerosis (ALS).