MicroRNA Function During Neuronal Reprogramming in Treating Spinal Cord Injury

项目总结： 治疗脊髓损伤的一个主要障碍是补充在脊髓损伤过程中丢失的神经元。 并恢复局部神经元电路以进行功能修复。干细胞移植疗法曾显示 很好的承诺。然而，它的疗效在临床试验、免疫排斥和伦理问题上并不令人满意。 仍然是有问题的。体内重新编程正在成为再生领域潜在的新突破 医药。这项创新技术将内源性神经胶质细胞转化为功能神经元进行修复 目的，绕过干细胞替代疗法面临的挑战性问题。上一首 PI实验室的研究表明，反应性星形胶质细胞可以成功地在原位转化为 阿尔茨海默病模型损伤脑和脑内功能神经元的过度表达 单一转录因子NeuroD1(Guo等人，2014；细胞干细胞最佳文章)。然而，分子 重新编程过程的机制仍然难以捉摸。MicroRNAs(MiRNAs)是一种小的非编码RNA 在神经发育和疾病过程中起着关键作用。MiRNAs的功能可能是广泛的 鉴于一个miRNA可能通过独特的不完全碱基配对机制调节多个靶基因 对细胞中的基因表达谱施加全球影响。在这项提议中，私家侦探将结合他的专业知识 对脊髓损伤和miRNA的影响，并检测在NeuroD1介导的小鼠神经元转化过程中miRNA的功能 SCI模型。这一提议的中心假设是miRNAs在神经元 重新编程过程，而miRNAs的强制表达以及NeuroD1可以重新编程反应性 星形胶质细胞分化为神经元进行脊髓损伤后的功能修复。PI提出了三个具体目标：1)确定 MiRNA在NeuroD1介导的损伤脊髓神经元转化中的作用；2)确定 脊髓损伤后miRNAs将反应性星形胶质细胞转化为神经元；3)确定脊髓损伤后星形胶质细胞功能整合 脊髓挫伤后miRNA转化神经元及其对动物行为的影响。完成本建议书 将展示miRNA介导的神经胶质细胞向神经元转化的可行性，并为治疗奠定基础 这种小RNA分子在未来作为合成药物的应用。公安局认为，这项提议将 为脊髓损伤和其他神经疾病带来一种新的治疗方法。

Project Summary: One major obstacle in treating spinal cord injury (SCI) is to replenish neurons that are lost during the course of injury and to restore local neuronal circuitry for functional repair. Stem cell transplantation therapy once showed great promise. However, its efficacy has not been satisfactory in clinical trials; immunorejection and ethical issues remain problematic. In vivo reprogramming is emerging as a potentially new breakthrough in regenerative medicine. This innovative technology literally converts endogenous glial cells into functional neurons for repair purposes, bypassing the challenging questions that stem cell replacement therapies are facing. Previous research from the PI’s lab has demonstrated that reactive astrocytes can be successfully converted in situ into functional neurons in both injured brain and brain of a model for Alzheimer’s disease by overexpression of a single transcription factor NeuroD1 (Guo et al, 2014; BEST of 2014 Article in Cell Stem Cell). However, molecular mechanisms of the reprogramming process remain elusive. MicroRNAs (miRNAs) are small non-coding RNAs that play pivotal roles during neural development and diseases. The function of miRNAs could be extensive given that one miRNA may regulate many target genes through the unique imperfect base-pairing mechanism exerting a global impact on the gene expression profile in a cell. In this proposal, the PI will combine his expertise on SCI and miRNA, and examine miRNA function during NeuroD1-mediated neuronal conversion in a mouse model of SCI. The central hypothesis of this proposal is that miRNAs play essential roles during the neuronal reprogramming process, and that forced expression of miRNAs, as well as NeuroD1, can reprogram reactive astrocytes into neurons for functional repair after SCI. The PI proposes three specific aims: 1) To determine miRNA function during NeuroD1-mediated neuronal conversion in the injured spinal cord; 2) To determine conversion of reactive astrocytes into neurons by miRNAs after SCI; 3) To determine functional integration of miRNA-converted neurons and their effects on animal’s behavior after contusive SCI. Completion of this proposal will show feasibility of miRNA-mediated glia-to-neuron conversion and lay out foundation for therapeutic application of this small RNA molecule as a synthetic drug in the future. The PI believes that this proposal will lead to a novel therapeutic treatment for SCI as well as other neurological disorders.