Identification of novel genes and networks governing hematopoietic stem cell development

Hematopoietic stem cells (HSCs) are capable of giving rise to all blood cell lineages throughout adulthood, and the generation of engraftable HSCs from human pluripotent stem cells is a major goal for regenerative medicine. Here, we describe a functional genome‐wide RNAi screen to identify genes required for the differentiation of embryonic stem cell (ESC) into hematopoietic stem/progenitor cells (HSPCs) in vitro . We report the discovery of novel genes important for the endothelial‐to‐hematopoietic transition and subsequently for HSPC specification. High‐throughput sequencing and bioinformatic analyses identified twelve groups of genes, including a set of 351 novel genes required for HSPC specification. As in vivo proof of concept, four of these genes, Ap2a1 , Mettl22 , Lrsam1 , and Hal , are selected for validation, confirmed to be essential for HSPC development in zebrafish and for maintenance of human HSCs. Taken together, our results not only identify a number of novel regulatory genes and pathways essential for HSPC development but also serve as valuable resource for directed differentiation of therapy grade HSPCs using human pluripotent stem cells. Synopsis In this study, the authors use a genome‐wide RNAi silencing approach to find stage‐specific gene networks required for HSPC development. A novel conserved group of genes is identified to be required for HSPC specification in zebrafish and the maintenance of human HSCs. A genome‐wide RNAi screen reveals genes and networks that regulate the development of hematopoietic stem/progenitor cells (HSPCs). Specific groups of genes important for distinct stages of HSPC differentiation are identified. The results are validated in zebrafish and in human hematopoietic stem cells (HSCs) using four conserved genes (Ap2a1, Mettl22, Lrsam1, and Hal). Graphical Abstract In this study, the authors use a genome‐wide RNAi silencing approach to find stage‐specific gene networks required for HSPC development. A novel conserved group of genes is identified to be required for HSPC specification in zebrafish and the maintenance of human HSCs.