Yvernogeau Laurent, Gautier Rodolphe, Khoury Hanane, Menegatti Sara, Schmidt Melanie, Gilles Jean-Francois, Jaffredo Thierry
Sorbonne Universités, UPMC Univ Paris 06, IBPS, UMR 7622, Laboratoire de Biologie du Développement, Paris 75005, France CNRS, UMR 7622, Inserm U 1156, IBPS, Laboratoire de Biologie du Développement, Paris 75005, France.
Institute of Biology Paris-Seine, Sorbonne Universités, UPMC Univ Paris 06, Cellular Imaging Facility, Paris 75005, France.
Development. 2016 Apr 15;143(8):1302-12. doi: 10.1242/dev.126714. Epub 2016 Mar 7.
Adult-type hematopoietic stem and progenitor cells are formed during ontogeny from a specialized subset of endothelium, termed the hemogenic endothelium, via an endothelial-to-hematopoietic transition (EHT) that occurs in the embryonic aorta and the associated arteries. Despite efforts to generate models, little is known about the mechanisms that drive endothelial cells to the hemogenic fate and about the subsequent molecular control of the EHT. Here, we have designed a stromal line-free controlled culture system utilizing the embryonic pre-somitic mesoderm to obtain large numbers of endothelial cells that subsequently commit into hemogenic endothelium before undergoing EHT. Monitoring the culture for up to 12 days using key molecular markers reveals stepwise commitment into the blood-forming system that is reminiscent of the cellular and molecular changes occurring during hematopoietic development at the level of the aorta. Long-term single-cell imaging allows tracking of the EHT of newly formed blood cells from the layer of hemogenic endothelial cells. By modifying the culture conditions, it is also possible to modulate the endothelial cell commitment or the EHT or to produce smooth muscle cells at the expense of endothelial cells, demonstrating the versatility of the cell culture system. This method will improve our understanding of the precise cellular changes associated with hemogenic endothelium commitment and EHT and, by unfolding these earliest steps of the hematopoietic program, will pave the way for future ex vivo production of blood cells.
成年型造血干细胞和祖细胞在个体发育过程中由内皮细胞的一个特殊亚群（称为造血内皮）形成，通过发生在胚胎主动脉和相关动脉中的内皮向造血转变（EHT）。尽管人们努力构建模型，但对于驱动内皮细胞走向造血命运的机制以及EHT随后的分子调控知之甚少。在这里，我们设计了一种无基质的可控培养系统，利用胚胎体节形成前中胚层来获得大量内皮细胞，这些内皮细胞随后在经历EHT之前分化为造血内皮。使用关键分子标记对培养物进行长达12天的监测，揭示了向造血系统的逐步分化，这让人联想到在主动脉水平的造血发育过程中发生的细胞和分子变化。长期单细胞成像能够追踪来自造血内皮细胞层的新形成血细胞的EHT。通过改变培养条件，还可以调节内皮细胞的分化或EHT，或者以牺牲内皮细胞为代价产生平滑肌细胞，这证明了细胞培养系统的多功能性。这种方法将增进我们对与造血内皮分化和EHT相关的精确细胞变化的理解，并且通过揭示造血程序的这些最早步骤，将为未来体外生产血细胞铺平道路。
