Shared mechanisms of astrocyte maturation in development and glioblastoma

项目摘要 胶质母细胞瘤（GBM）是成人中最常见和最致命的原发性脑肿瘤。最近的工作继续 我支持这种癌症（像许多其他癌症一样）与癌症的增殖和分化程序相呼应的想法。 早期发展阶段。像GBM这样的神经系统癌症基本上被“锁定”在一个 开发程序并保留在开发期间指导这些细胞群的控制， 新的和令人兴奋的机会。此外，它强调需要确定分子触发器 在发育过程中控制未成熟祖细胞向静止成熟星形胶质细胞的转变。 在这个项目中，我们将测试的假设，主转录调控足以驱动星形胶质细胞 这些因子可用于启动GBM-星形胶质细胞内停滞的成熟。的能力 单个或小群体的转录因子驱动细胞命运或成熟的变化， 在多种细胞类型中表现出，包括神经元和神经胶质。开始，我们使用现有的转录组， 表观基因组和DNA结合数据，以确定一组候选转录因子，我们 假设催化星形胶质细胞成熟过程。我们将测试这些转录因子是否 能够诱导未成熟的人星形胶质细胞的早熟成熟，通过使用 反映其发育活动的方案。作为一个模型系统，我们使用人类iPSC衍生的皮质 类器官，它提供了一个多细胞平台，其中星形细胞发生和成熟是内源性的 沿着类似于在胎儿和出生后早期人脑中观察到的时间尺度。 我们还将询问星形胶质细胞成熟的发育轨迹在GBM的背景下是如何受到干扰的， 将来自类器官系统的成熟人星形胶质细胞的表观基因组谱与来自 GBM手术切除这种比较将把GBM-星形胶质细胞分化置于正常细胞分化的背景下。 发育轨迹并揭示潜在的转录因子，其缺失可能导致停滞 成熟神经胶质瘤形成的病理生物学中一个重要的可能性是， GBM-星形胶质细胞内积累的蛋白质使它们不能接受成熟诱导转录因子。因此，在本发明中， 在最后一组实验中，我们将使用携带驱动GBM突变的同基因iPSC系来测试它们的影响 对成熟诱导转录因子的感受性。总之，这些研究将有助于教我们如何和 GBM细胞在其发育过程中停滞，并提供了追求分化的新途径 减轻这些致命肿瘤的方案。

Project Summary Glioblastoma (GBM) is the most common and deadliest primary brain tumor in adults. Recent work continues to support the idea that this cancer (like many others) echoes the proliferation and differentiation programs from earlier developmental stages. The possibility that neurological cancers like GBM are essentially `locked in' to a developmental program and retain the controls that instruct these cell populations during development opens new and exciting opportunities. Furthermore, it places an emphasis on the need to identify the molecular triggers that govern the transition of immature progenitor cells to quiescent mature astrocytes during development. In this project we will test the hypothesis that master transcriptional regulators are sufficient for driving astrocyte maturation and that these factors can be used to jump-start stalled maturation within GBM-astrocytes. The ability of individual or small groups of transcription factors to drive cell fate or maturation changes has been demonstrated in a variety of cell types, including neurons and glia. To begin, we used existing transcriptomic, epigenomic, and DNA-binding data to identify a targeted set of candidate transcription factors that we hypothesize catalyze the astrocyte maturation process. We will test whether these transcription factors are capable of inducing precocious maturation in immature human astrocytes by manipulating their expression using schemes that mirror their developmental activity. As a model system, we are using human iPSC-derived cortical organoids, which provides a multicellular platform in which astrogenesis and maturation occurs endogenously along a timescale analogous to what is observed in the fetal and early postnatal human brain. We will also ask how the developmental trajectory of astrocyte maturation is perturbed in the setting of GBM by comparing epigenomic profiles of maturing human astrocytes from the organoid system with single cell data from surgical GBM resections. This comparison will place GBM-astrocyte differentiation in the context of the normal developmental trajectory and reveal potential transcription factors whose absence may contribute to stalled maturation. An important possibility in the pathobiology of gliomagenesis is that the heterogeneous mutations accumulated within GBM-astrocytes render them unreceptive to maturation-inducing transcription factors. Thus, in a final set of experiments, we will use isogenic iPSC lines harboring driver GBM mutations to test their influence on the receptivity to maturation-inducing transcription factors. Together, these studies will help teach us how and where GBM cells are stalled in their developmental programs and offer novel avenues to pursue differentiation schemes to mitigate these deadly tumors.