A myeloid maturation program initiated by nucleotide depletion during S phase [ATAC-Seq]. A myeloid maturation program initiated by nucleotide depletion during S phase [ATAC-Seq]

Certain cancers, such as acute myeloid leukemia (AML), are caused by malignant stem cells that fail maturation. We sought to mechanistically understand how metabolism might regulate cell fate decisions and to identify metabolic differentiation agents that might be leveraged therapeutically. We find that nucleotide – purine, pyrimidine, and deoxynucleotide – depletion leads to AML differentiation by way of replication stress. Modulation of nucleotide pools leads to transcriptional reprogramming, epigenetic remodeling, and initiation of differentiation which is dependent on the myeloid regulating transcription-factor PU.1. By single-cell RNA sequencing and microscopy, we find that reprogramming downstream of nucleotide depletion occurs as cells undergo replication stress and that the cell fate decision is initiated prior to completion of the cell cycle. Together, these findings suggest that nucleotide metabolism is a critical determinant of hematopoietic progenitor cell fate, clarify the coordination of the fate decision with the cell cycle, and expand upon the class of inhibitors that can be developed or repurposed as novel differentiation therapy. Overall design: Cell lines were treated with vehicle or drug for the indicated times and ATACseq was performed.

某些癌症，例如急性髓系白血病（acute myeloid leukemia, AML），由成熟障碍的恶性干细胞引发。本研究旨在从机制层面解析代谢如何调控细胞命运决定，并筛选可用于治疗的代谢性分化调节剂。本研究发现，核苷酸——包括嘌呤、嘧啶及脱氧核苷酸——耗竭可通过复制应激途径诱导AML细胞分化。核苷酸池的调控可引发转录重编程、表观遗传重塑，并启动分化过程，该过程依赖于髓系调控转录因子PU.1。通过单细胞RNA测序与显微观测，本研究发现，核苷酸耗竭下游的重编程过程发生于细胞遭受复制应激之时，且细胞命运决定于细胞周期完成前即已启动。综上，本研究结果表明，核苷酸代谢是造血祖细胞命运的关键调控因子，阐明了细胞命运决定与细胞周期的协同机制，并拓展了可被开发或重新定位为新型分化治疗药物的抑制剂类别。实验整体设计：按指定时间用溶剂对照或药物处理细胞系，随后进行转座酶可及性测序（ATAC-seq）。