McMaster University, Hamilton, ON L8N 3Z5, Canada.
J Cell Sci. 2011 May 1;124(Pt 9):1445-52. doi: 10.1242/jcs.077511. Epub 2011 Apr 12.
Mechanisms that govern hematopoietic lineage specification, as opposed to the expansion of committed hematopoietic progenitors, from human pluripotent stem cells (hPSCs) have yet to be fully defined. Here, we show that within the family of genes called inhibitors of differentiation (ID), ID1 and ID3 negatively regulate the transition from lineage-specified hemogenic cells to committed hematopoietic progenitors during hematopoiesis of both human embryonic stem cells (hESCs) and human induced pluripotent stem cell (hiPSCs). Upon hematopoietic induction of hPSCs, levels of ID1 and ID3 transcripts rapidly increase, peaking at the stage of hemogenic precursor emergence, and then exclusively decrease during subsequent hematopoietic commitment. Suppression of ID1 and ID3 expression in hemogenic precursors using specific small interfering RNAs augments differentiation into committed hematopoietic progenitors, with dual suppression of ID1 and ID3 further increasing hematopoietic induction compared with upon knockdown of each gene alone. This inhibitory role of ID1 and ID3 directly affects hemogenic precursors and is not dependent on non-hemogenic cells of other lineages within developing human embryoid bodies from hESCs or hiPSCs. Our study uniquely identifies ID1 and ID3 as negative regulators of the hPSC-hematopoietic transition from a hemogenic to a committed hematopoietic fate, and demonstrates that this is conserved between hESCs and hiPSCs.
目前尚未完全阐明调控造血谱系特化（与造血定向祖细胞的扩增相反）的机制，从人类多能干细胞（hPSC）中分离出来。在这里，我们发现，在分化抑制因子（ID）家族基因中，ID1 和 ID3 负调控人类胚胎干细胞（hESC）和人类诱导多能干细胞（hiPSC）造血过程中，从谱系特异性造血细胞向定向造血祖细胞的过渡。在 hPSC 造血诱导后，ID1 和 ID3 转录本的水平迅速增加，在造血前体出现阶段达到峰值，然后在随后的造血定向过程中特异性降低。使用特异性小干扰 RNA 抑制造血前体中的 ID1 和 ID3 表达可增强向定向造血祖细胞的分化，与单独敲低每个基因相比，双重抑制 ID1 和 ID3 进一步增加了造血诱导。ID1 和 ID3 的这种抑制作用直接影响造血前体，而不依赖于 hESC 或 hiPSC 发育中的人胚体中其他谱系的非造血细胞。我们的研究首次鉴定出 ID1 和 ID3 是 hPSC 从造血到定向造血命运的造血过渡的负调控因子，并证明其在 hESC 和 hiPSC 之间是保守的。
