Metabolic Atlas of Early Human Cortex Identifies Regulators of Cell Fate Transitions

Characterization of cell type emergence during human cortical development, which enables unique human cognition, has focused primarily on anatomical and transcriptional characterizations. Metabolic processes in the human brain that allow for rapid expansion, but contribute to vulnerability to neurodevelopmental disorders, remain largely unexplored. We performed a variety of metabolic assays in primary tissue and stem cell derived cortical organoids and observed dynamic changes in core metabolic functions, including an unexpected increase in glycolysis during late neurogenesis. By depleting glucose levels in cortical organoids, we increased outer radial glia, astrocytes, and inhibitory neurons. We found the pentose phosphate pathway (PPP) was impacted in these experiments and leveraged pharmacological and genetic manipulations to recapitulate these radial glia cell fate changes. These data identify a new role for the PPP in modulating radial glia cell fate specification and generate a resource for future exploration of additional metabolic pathways in human cortical development. Overall design: 10X GEMX single-cell (sc) and single-nuclei (sn) RNA-sequencing of cortical organoids subjected to a metabolic perturbation. These perturbations were 1) glucose depletion followed by snRNA-seq 2) pharmacologic inhibition of the pentose phosphate pathway followed by snRNA-seq or 3) knockdown of pentose phosphate pathway enzymes

针对赋予人类独特认知能力的人类大脑皮层发育过程中细胞类型出现的特征解析，既往研究主要聚焦于解剖学与转录组层面的特征分析。可支持人脑快速扩张、却同时增加神经发育障碍易感性的代谢过程，目前仍未得到充分研究。
本研究对原代组织及干细胞来源的皮层类器官开展了多类代谢检测实验，观察到核心代谢功能的动态变化，其中包括神经发生晚期糖酵解水平的意外上调。通过降低皮层类器官的葡萄糖浓度，我们发现外部放射状胶质细胞、星形胶质细胞与抑制性神经元的数量显著增加。
本研究发现上述实验中磷酸戊糖途径（pentose phosphate pathway, PPP）受到调控，并通过药理学与遗传学操作手段成功重现了放射状胶质细胞的命运改变过程。
本研究数据揭示了磷酸戊糖途径在调控放射状胶质细胞命运特化中的全新功能，并为未来探索人类皮层发育过程中的其他代谢通路提供了宝贵的研究资源。
实验整体设计：对经代谢扰动处理的皮层类器官开展10X GEMX单细胞（single-cell, sc）与单细胞核（single-nuclei, sn）RNA测序。本次代谢扰动包含三类处理方案：1）葡萄糖剥夺后进行单细胞核RNA测序；2）磷酸戊糖途径药理学抑制后进行单细胞核RNA测序；3）磷酸戊糖途径相关酶的基因敲降。