Reprogramming Cell Fate for Repair

项目摘要 中枢神经元是高度特化和长寿的细胞，形成精确的电路来支持正常的大脑 功能大脑皮层不会增加新的神经元来维持或增加功能，也不会取代神经元。 因受伤或疾病而死亡。人脑中的成年海马神经发生表明，成年神经发生是 可能然而，对于人类大脑皮层，有两种可能的神经元添加策略，1） 用细胞培养产生的外源性神经元替代，或2）通过转化来募集局部内源性细胞 它们是神经元。本项目的最终目标是研究第二种方法， 人神经胶质祖细胞的神经元重编程能力，并评估其功能性 一体化为了使神经元重编程具有治疗潜力，有必要精确地 使神经元具有可预测和可持续的存活率。目标1将解决生存问题 效率和亚型精度，开发创新的载体工具箱进行这些研究。但 这些被诱导的神经元的真实性如何也是一个问题。强制转录因子 表达可能导致某些神经元表型的表达，包括激发动作的能力 潜力，而不一定导致功能成熟。虽然我们的初步数据显示， 尽管迄今为止报道了最先进的神经元形态学，但真正的回路整合仍有待证实。目的2 的目的是利用当前的连通性跟踪的进展，调查新的集成状态 将神经元设计成本地和远程回路。特别是Aim 2b将询问新工程神经元是否 能够活跃地在大脑中重新布线。我们看到这种方法在重建任何受损的 回路，最终包括那些经历失调，如癫痫或神经性疼痛。有 没有关于将人脑中的非神经元细胞重新编程为新神经元的能力的信息， 尽管迫切需要这些数据来推进该方法的治疗应用。因为我们不能 在人类大脑中进行这些实验，Aim 3将开发一种嵌合模型，将人类细胞移植到 啮齿类动物脑，以允许靶向人类神经胶质祖细胞进行神经元重编程，并评估 电路与大鼠神经元整合的程度。通过使用人类iPSC衍生的神经胶质祖细胞作为我们的起点， 人口，将有可能扩大这些研究，以解决疾病特异性因素的影响，以及 为最终的患者特异性治疗提供基础。

Project Summary Central neurons are highly specialized and long-lived cells that form precise circuitry to support normal brain function. The cerebral cortex does not add new neurons to maintain or increase function nor replace neurons lost to injury or disease. Adult hippocampal neurogenesis in the human brain shows that adult neurogenesis is possible. However, for human cerebral cortex, there are two possible strategies for neuronal addition, 1) replace with exogenous neurons generated by cell culture or 2) recruit local endogenous cells by converting them to neurons. The ultimate goal of this project is to investigate the second approach and to establish the capacity for neuronal reprogramming of human glial progenitor cells and to assess their potential for functional integration. For neuronal reprogramming to have therapeutic potential, it will be necessary to precisely engineer neurons with a predictable and sustainable rate of survival. Aim 1 will address issues of survival efficiency and subtype precision, developing an innovative vector toolbox to conduct these studies. But there also remains the question of how authentic these induced neurons become. The forced transcription factor expression may cause expression of certain neuronal phenotypes, including the capacity to fire an action potential, without necessarily resulting in functional maturation. While our preliminary data demonstrate the most advanced neuronal morphology reported to date, true circuit integration still remains to be shown. Aim 2 is designed to utilize current advances in connectivity tracing to investigate the state of integration of newly engineered neurons into local and distant circuits. In particular Aim 2b will ask if newly engineered neurons are capable of actively rewiring in the brain. We see application for this approach in rebuilding any damaged circuit, including ultimately those experiencing dysregulation such as in epilepsy or neuropathic pain. There is no information about the capacity to reprogram non-neuronal cells in the human brain into new neurons, despite the compelling need for such data to advance therapeutic application of this approach. As we cannot conduct these experiments in human brain, Aim 3 will develop a chimeric model, engrafting human cells into rodent brain to allow targeting of human glial progenitor cells for neuronal reprogramming and evaluating the extent of circuit integration with rat neurons. By using human iPSC-derived glial progenitor cells as our starting population, it will be possible to expand these studies to address the impact of disease-specific factors as well as providing a basis for eventual patient-specific therapies.