PT - JOURNAL ARTICLE AU - Dionna M. Kasper AU - Jared Hintzen AU - Yinyu Wu AU - Joey J. Ghersi AU - Hanna K. Mandl AU - Kevin E. Salinas AU - William Armero AU - Zhiheng He AU - Ying Sheng AU - Yixuan Xie AU - Daniel W. Heindel AU - Eon Joo Park AU - William C. Sessa AU - Lara K. Mahal AU - Carlito Lebrilla AU - Karen K. Hirschi AU - Stefania Nicoli TI - The N-Glycome regulates the endothelial-to-hematopoietic transition AID - 10.1101/602912 DP - 2020 Jan 01 TA - bioRxiv PG - 602912 4099 - http://biorxiv.org/content/early/2020/08/06/602912.short 4100 - http://biorxiv.org/content/early/2020/08/06/602912.full AB - Hematopoietic stem and progenitor cells (HSPCs) that establish and maintain the blood system in adult vertebrates arise from the transdifferentiation of hemogenic endothelial cells (hemECs) during embryogenesis. This endothelial-to-hematopoietic transition (EHT) is tightly regulated, but the mechanisms are poorly understood. Here, we show that microRNA (miR)-223-mediated regulation of N-glycan biosynthesis in endothelial cells (ECs) regulates EHT. Single cell RNA-sequencing revealed that miR-223 is enriched in hemECs and in oligopotent nascent HSPCs. miR-223 restricts the EHT of lymphoid/myeloid lineages by suppressing the expression of mannosyltransferase alg2 and sialyltransferase st3gal2, two enzymes involved in N-linked protein glycosylation. High-throughput glycomics of ECs lacking miR-223 showed a decrease of high mannose versus sialylated complex/hybrid sugars on N-glycoproteins involved in EHT such as the metalloprotease Adam10. Endothelial-specific expression of an N-glycan Adam10 mutant or of the N-glycoenzymes phenocopied the aberrant HSPC production of miR-223 mutants. Thus, the N-glycome plays a previously unappreciated role as an intrinsic regulator of EHT, with specific mannose and sialic acid modifications serving as key endothelial determinants of their hematopoietic fate.One Sentence Summary The N-glycan “sugar code” governs the hematopoietic fate of endothelial cells and regulates blood stem cell production in vivo.Competing Interest StatementThe authors have declared no competing interest.