Cell extrinsic factors' roles on direct conversion to human induced neural crest

 描述(由申请人提供)：外周神经系统(PNS)的普遍遗传缺陷和获得性损伤在我们的医疗保健系统中造成了一个重大的社会经济问题。然而，由于难以获得患者样本，对人类三叉神经节组织的详细研究相对较少。我们已经证明，外周神经元和雪旺细胞可以从人胚胎干细胞(HESCs)和人诱导多能干细胞(HiPSCs)分化而来；然而，这个过程非常漫长(至少超过5个月)。最近，我们开发了一种新的方法，可以在两周内将人成纤维细胞直接转化为诱导的神经脊(INC)。我们的Inc.群体表现出神经脊特有的细胞和分子特征。尽管Inc.群体在单细胞水平上表现出多能性，但他们更容易受到感觉神经元命运的影响，而不是自主神经元谱系。在发育过程中，细胞命运由细胞外在因素决定，如生长因子和形态因子。如果这些细胞外在因素在Inc.的产生过程中也控制着细胞的命运，我们可能能够改变Inc.的分化潜力。这一假说引发了一个问题，即细胞外部因素(如腹侧化和/或尾化信号)的调节是否会影响直接转换过程中的细胞命运，这与这一机制在发育细胞决定中的作用相同。目前，以Our Inc.为例的直接转化依赖于致癌病毒转导传递的转录因子。我们的第二个问题是，“非遗传的”小分子能否以及如何实现人成纤维细胞充分直接转化为诱导的神经峰？我们目前的INC诱导系统适合于研究这些关于细胞命运可塑性的基本问题，因为它只使用了单一的转录因子，以及高度定量的检测方法(FACS检测Sox10：：GFP)。我们拟议的实验有望：(I)扩大和加强我们目前关于一般的“遗传因素依赖”直接转换的概念，以及(Ii)加快对PNS疾病的广泛研究，例如通过直接从Charcot-Marie-Tooth1A(CMT1A)或家族性自主神经障碍患者的成纤维细胞提供疾病特异性雪旺细胞或交感神经元。

 DESCRIPTION (provided by applicant): The prevalent genetic defects and acquired injuries of the peripheral nervous system (PNS) cause a significant socioeconomic issue on our healthcare system. However, there are relatively few detailed studies of human PNS tissues, due to the difficulty to obtaining patient samples. We have shown that peripheral neurons and Schwann cells can be derived from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs); however, the process is arduously long (at least over 5 months). Recently we developed an alternative, a new method that directly converts human fibroblasts into induced neural crest (iNC) in only two weeks. Our iNC population exhibits neural crest- specific cellular and molecular characteristics. Although the iNC population shows multipotency in a single cell level, they are more prone to a sensory neuron fate, rather than autonomic neuron lineages. During development, cell fates are determined by cell extrinsic factors, such as growth factors and morphogens. If such cell extrinsic factors also govern cell fates during generation of iNC, we may be able to change the differentiation potential of the iNC. This hypothesis incites a question, whether modulation of cell extrinsic factors (such as ventralization and/or caudalization cues) can influence the cellular fate during direct conversion, in the same way that this mechanism operates in developmental cell determination. Currently direct conversion, exemplified by our iNC, is dependent on transcription factors delivered by oncogenic viral transduction. Our second question is whether and how `non-genetic' small molecules can achieve sufficient direct conversion of human fibroblasts to induced neural crest? Our current iNC induction system is suitable for investigating these fundamental questions about cell fate plasticity, because it employs only a single transcription factor, along with highly quantitative detection method (SOX10::GFP detection by FACS). Our proposed experiments are expected to: (i) expand and strengthen our current conception of general `genetic factor-dependent' direct conversion, and (ii) accelerate a wide range of research on PNS disorders, e.g. by providing disease-specific Schwann cells or sympathetic neurons directly from fibroblasts of Charcot-Marie- Tooth1A (CMT1A) or familial dysautonomia patients.