Shared mechanisms of astrocyte maturation in development and glioblastoma

项目摘要 胶质母细胞瘤(GBM)是成人最常见、最致命的原发脑肿瘤。最近的工作继续进行 支持这种癌症(像许多其他癌症一样)呼应了来自 早期发育阶段。像GBM这样的神经性癌症本质上被锁定在一个 发育程序和保留在发育过程中指示这些细胞群体的控制 新的令人兴奋的机会。此外，它强调了确定分子触发因素的必要性 在发育过程中控制未成熟的祖细胞向静止的成熟星形胶质细胞的转变。 在这个项目中，我们将检验这一假设，即主要的转录调节因子足以驱动星形胶质细胞 这些因素可以用来启动GBM星形胶质细胞内停滞的成熟。一种能力 驱动细胞命运或成熟变化的单个或小群转录因子 在多种细胞类型中均有表达，包括神经元和神经胶质细胞。首先，我们使用了现有的转录本， 表观基因组学和DNA结合数据，以确定我们 假说催化了星形胶质细胞的成熟过程。我们将测试这些转录因子是否 能够通过操纵未成熟的人星形胶质细胞的表达来诱导其早熟 反映他们发育活动的计划。作为一个模型系统，我们使用的是人类IPSC来源的皮质 类有机物，它提供了一个多细胞平台，在这个平台上，星形发生和成熟发生在内源 沿着类似于在胎儿和出生后早期人类大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是如何在GBM的背景下被干扰的 来自类器官系统的成熟人星形胶质细胞的表观基因组图谱与来自 手术切除基底膜。这一比较将把GBM-星形胶质细胞分化放在正常的背景下 发展轨迹并揭示潜在的转录因子，其缺失可能导致停滞 成熟。在胶质瘤发生的病理生物学中的一个重要可能性是异质性突变 在GBM-星形胶质细胞内积聚，使它们不能接受成熟诱导转录因子。因此， 在最后一组实验中，我们将使用含有驱动器GBM突变的等基因iPSC系来测试它们的影响 关于成熟诱导转录因子的接受性。总之，这些研究将帮助我们教会我们如何和 在那里，GBM细胞在其发育程序中停滞不前，并提供了寻求分化的新途径 减轻这些致命肿瘤的计划。

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.