Screening for regulators of human embryonic axis elongation in vitro

引导多能干细胞（PSCs）在培养皿中产生（“分化”）各种类型的细胞是一种了解胚胎如何发育的有吸引力的工具，也是一种有希望的治疗途径。然而，我们产生与脊髓下部（胸椎、腰椎和骶骨区域）和骨骼肌相对应的细胞类型的能力目前非常有限。这是因为传统的PSC分化方法不能产生这些细胞类型的共同胚胎前体细胞，即神经中胚层祖细胞（nmp）。我们最近成功地设计了一种将人类PSCs有效转化为NMPs （hNMPs）的方案。这些体外生成的nmp似乎是产生下脊髓和骨骼肌细胞的有希望的起始材料。然而，我们对hNMPs产生这些细胞类型的信号和分子机制仍然知之甚少。这里提出的实验将测试各种化学物质，以确定最佳的“配方”，以推动人类nmp只成为脊髓或骨骼肌细胞。我们还将研究某些被称为转录因子的蛋白质与NMPs DNA的结合如何影响它们保留NMPs或分化为脊髓/骨骼肌细胞的决定。这项工作将有助于更好地理解NMP生物学，并为其分化产品在临床中的使用铺平道路。

Directing pluripotent stem cells (PSCs) to generate ("differentiate") various cell types in the petri dish is an attractive tool for understanding how embryos develop and a promising route towards therapies. However, our ability to produce cell types corresponding to the lower spinal cord (the thoracic, lumbar and sacral regions) and skeletal muscle is currently very limited. This is because conventional PSC differentiation methods fail to produce the common embryonic precursor of these cell types known as neuromesodermal progenitors (NMPs). We have recently succeeded in devising a protocol for converting efficiently human PSCs into NMPs (hNMPs). These in vitro generated NMPs appear to be a promising starting material for producing lower spinal cord and skeletal muscle cells. However, we still do not know much about the signals and the molecular mechanisms driving the generation of these cell types from hNMPs. The experiments proposed here will test various chemicals in order to identify the best "recipes" for pushing human NMPs to become exclusively either lower spinal cord or skeletal muscle cells. We will also examine how the binding of certain proteins known as transcription factors to the DNA of NMPs influences their decision to remain NMPs or differentiate into spinal cord/skeletal muscle cells. This work will lead to a better understanding of NMP biology and pave the way for the use of their differentiation products in the clinic.