Generating transplantable neurons by in vivo combinatorial screening of transcrip

体内组合筛选转录调节因子RNA生成可移植神经元 问题：仅在美国，神经元损伤、退行性疾病以及帕金森和亨廷顿病、癫痫和中风等疾病就影响着数千万人，随着人口老龄化，这一问题正变得更加严重。尽管正在投入大量的努力来识别所涉及的分子过程，但现有的化学和物理疗法并不能保证除了短期的症状补救之外，恢复丢失的神经元电路。一个潜在的解决方案可能是使用组织移植来恢复神经元功能。已经有人体试验表明，尽管移植的效果各不相同，但在帕金森氏症(PD)和亨廷顿病(HD)中，移植已经导致了功能恢复。细胞替代治疗癫痫和中风已经在几个啮齿动物研究中显示出希望，视网膜细胞移植治疗退行性眼病正在几个实验室进行评估。尽管仍有许多未知之处，但在各种情况下，已经观察到移植神经元与现有神经元网络的整合导致了功能的改善，而不仅仅是由于移植细胞释放的营养因子。几项研究还表明，当移植物中存在正确的细胞类型时，成人大脑具有显著的能力提供信号线索，指导神经元突起的生长，并诱导与所需目标的突触形成。对比啮齿动物更大的动物进行的异种移植研究表明，这些信号可以在很长的距离内发挥作用。然而，尽管组织移植可能具有巨大的潜力，但正如该提案所概述的那样，存在许多科学上的未知数和几个根本性的挑战。应对这些挑战的复杂性目前超出了世界上最大的实验室的能力范围，可能需要部署系统的高通量方法，这些方法不仅将解决基本的生物学问题，快速无偏见地测试各种假说，而且还将提供即使有希望，也可转化为临床试验的结果。挑战：(1)人胎儿或iPS来源的细胞太稀少或太致癌，不能临床使用，(2)移植细胞过于异质，(3)目前不可能在正确和同步的阶段制备移植细胞，(4)移植的物理位置因实验而异，(5)现有的体内移植检测方法太慢，无法筛选出大量不同的假设。创新与方法论：在这里，我们提出了一种系统的、公正的、体内的、大规模的、高通量的方法来克服这些对移植神经元组织的体外分化和体内测试的挑战。本文提出的方法学适用于大多数移植范例。我们将开发的关键技术和策略包括：(A)无遗传修饰的RNA介导的核重新编程；(B)通过大规模并行技术系统地超高通量筛选RNA转录因子鸡尾酒对人类细胞谱系进行重新编程；(C)将人类细胞高通量移植到啮齿动物体内(以最小的啮齿动物牺牲)，以及对神经元存活和整合的体内分析。

Generating transplantable neurons by in vivo combinatorial screening of transcription regulator RNAs Problem: Neuronal injuries, degenerative diseases, and disorders such as Parkinson's and Huntington's diseases, epilepsy, and stroke affect tens of millions of individuals in the USA alone, and are becoming a more severe problem with the aging population. Although significant effort is being invested for identification of the molecular processes involved, existing chemical and physical therapies do not promise restoration of lost neuronal circuits beyond the short term remedy of symptoms. A potential solution could be the use of tissue transplantation to restore neuronal function. There have been human trials where transplantations, although variably, have resulted in functional recovery in Parkinson's (PD) and Huntington's (HD) diseases. Cell replacement for epilepsy and stroke has shown promise in several rodent studies, and the transplantation of retinal cells to treat degenerative eye diseases is under evaluation in several laboratories. Although there are still many unknowns, in various cases, it has been observed that functional improvements occurred owing to the integration of grafted neurons into existing neuronal networks, and was not simply due to trophic factors released by the transplanted cells. Several studies have also shown that the adult brain is remarkably capable of providing signaling cues that guide the growth of neuronal processes and induce formation of synapses with desired targets when correct cell types are present within the grafts. Xenograft studies with animals larger than rodents have shown that these cues can function over long distances. However, while tissue transplantation may have significant potential, there are many scientific unknowns and several fundamental challenges exist as outlined in this proposal. Handling complexity of these challenges is currently beyond the capabilities of the largest laboratories in the world, and will likely require deployment of systematic high-throughput approaches that will not only address fundamental biological questions and rapidly test various hypotheses without bias, but also provide results that are, if promising, translatable to clinical trials. Challenges: (1) Human fetal or iPS-derived cells are either too scarce or tumorogenic for clinical use, (2) Transplanted cells are too heterogeneous, (3) Preparation of transplanted cells in the correct and synchronized stages is currently impossible, (4) Physical site of transplantation significantly varies from experiment to experiment, (5) Existing in vivo transplantation assays are too slow for screening of multitudes of different hypotheses. Innovation & Methodology: Here, we propose a systematic, unbiased, in vivo, large-scale, and high throughput approach for overcoming these challenges to in vitro differentiation and in vivo testing of transplanted neuronal tissues. The proposed methodologies here are applicable to most transplantation paradigms. The key technologies and strategies we will develop include: (A) RNA-mediated nuclear reprogramming without genetic modification, (B) Reprogramming human cell lineages by systematic ultra-high-throughput screening of RNA transcription factor cocktails using a massively parallel technology, (C) High-throughput transplantation of human cells into rodents (with minimal rodent sacrifice) and in vivo analysis of neuronal survival and integration.