Reprogramming Cell Fate for Repair

项目摘要 中枢神经元是高度专门化和长寿的细胞，它们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 因受伤或疾病而失去的。人脑中的成年海马神经发生表明，成人的神经发生是 有可能。然而，对于人类大脑皮层，有两种可能的神经元添加策略：1) 替换为细胞培养产生的外源性神经元或2)通过转化来招募本地内源性细胞 将它们转化为神经元。这个项目的最终目标是调查第二种方法，并建立 人神经胶质前体细胞的神经元重编程能力及其功能潜能的评估 整合。为了使神经元重新编程具有治疗潜力，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 效率和亚型精确度，开发一个创新的载体工具箱来进行这些研究。但在那里 还有一个问题是，这些诱导神经元变得有多真实。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，但不一定会导致功能成熟。虽然我们的初步数据表明 到目前为止，大多数高级神经元形态的报道，真正的电路整合仍有待展示。目标2 旨在利用当前在连接跟踪方面的进展来调查新的 将神经元改造成本地和远程电路。特别是，Aim 2b将询问新设计的神经元是否 能够主动地在大脑中重新连接。我们看到这种方法在重建任何受损的 最终包括那些经历失调的人，如癫痫或神经病理性疼痛。的确有 没有关于将人类大脑中的非神经细胞重新编程为新神经元的能力的信息， 尽管迫切需要这样的数据来推进这一方法的治疗应用。因为我们不能 在人脑中进行这些实验，Aim 3将开发一个嵌合模型，将人类细胞移植到 啮齿类动物大脑允许靶向人类神经胶质前体细胞进行神经元重新编程和评估 与大鼠神经元的电路整合程度。以人IPSC来源的神经胶质前体细胞为起点 对于人口，将有可能扩大这些研究，以解决疾病特有因素的影响 为最终针对患者的治疗提供了基础。

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.