Hematopoietic Stem Cell Development in Mammalian Embryos.

Area of Science:

• Developmental biology
• Hematopoiesis
• Stem cell biology

Background:

• Hematopoietic stem cells (HSCs) are crucial for lifelong blood cell production.
• Understanding HSC origins and development is key to regenerative medicine and treating blood disorders.

Approach:

• This review synthesizes recent findings from single-cell technologies in mouse and human embryonic development.
• Focuses on the vascular origin of HSCs and hemogenic endothelial cells (HECs).
• Examines epigenetic mechanisms regulating HSC generation.

Key Points:

• HSCs originate from arterial HECs, a conserved feature in mouse and human embryos.
• Pre-HSCs can be isolated and characterized at the single-cell level, revealing heterogeneity.
• Epigenetic factors like lncRNAs, DNA methylation, and RNA splicing are critical for HSC generation.
• Earliest human hematopoietic progenitors arise from the yolk sac, with myeloid bias.
• Development of diverse human hematopoietic lineages, including lymphoid and myeloid cells, is detailed.

Conclusions:

• Single-cell technologies have significantly advanced our understanding of HSC emergence and early hematopoiesis.
• Conserved mechanisms in mouse and human embryos provide insights into HSC development and potential therapeutic targets.