Hematopoietic stem cells (HSCs) are self-renewing multipotent stem cells that generate mature blood lineages throughout life. They, together with hematopoietic progenitor cells (collectively known as HSPCs), emerge from hemogenic endothelium in the floor of the embryonic dorsal aorta by an endothelial-to-hematopoietic transition (EHT). Here we demonstrate that transforming growth factor β (TGFβ) is required for HSPC specification and that it regulates the expression of the Notch ligand Jagged1a in endothelial cells prior to EHT, in a striking parallel with the epithelial-to-mesenchymal transition (EMT). The requirement for TGFβ is two fold and sequential: autocrine via Tgfβ1a and Tgfβ1b produced in the endothelial cells themselves, followed by a paracrine input of Tgfβ3 from the notochord, suggesting that the former programs the hemogenic endothelium and the latter drives EHT. Our findings have important implications for the generation of HSPCs from pluripotent cells in vitro.
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http://dx.doi.org/10.1016/j.devcel.2016.06.024 | DOI Listing |
Int J Mol Sci
December 2024
Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Mammalian blood cells originate from specialized 'hemogenic' endothelial (HE) cells in major arteries. During the endothelial-to-hematopoietic transition (EHT), nascent hematopoietic stem cells (HSCs) bud from the arterial endothelial wall and enter circulation, destined to colonize the fetal liver before ultimately migrating to the bone marrow. Mechanisms and processes that facilitate EHT and the release of nascent HSCs are incompletely understood, but may involve signaling from neighboring vascular endothelial cells, stromal support cells, circulating pre-formed hematopoietic cells, and/or systemic factors secreted by distal organs.
View Article and Find Full Text PDFFront Cell Dev Biol
December 2024
Microscopic and Developmental Anatomy, Tokyo Women's Medical University, Tokyo, Japan.
Most blood cells derive from hematopoietic stem cells (HSCs), originating from endothelial cells. The induction of HSCs from endothelial cells occurs during mid-gestation, and research has revealed multiple steps in this induction process. Hemogenic endothelial cells emerge within the endothelium, transition to hematopoietic cells (pre-HSCs), and subsequently mature into functional HSCs.
View Article and Find Full Text PDFCells
November 2024
Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
During mouse development, hematopoietic cells first form in the extraembryonic tissue yolk sac. Hematopoietic stem cells (HSCs), which retain their ability to differentiate into hematopoietic cells for a long time, form intra-aortic hematopoietic cell clusters (IAHCs) in the dorsal aorta at midgestation. These IAHCs emerge from the hemogenic endothelium, which is the common progenitor of hematopoietic cells and endothelial cells.
View Article and Find Full Text PDFDevelopment
November 2024
Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London EC1M 6BQ, UK.
Hematopoietic stem cells (HSCs) sustain life-long hematopoiesis and emerge during mid-gestation from hemogenic endothelial progenitors via an endothelial-to-hematopoietic transition (EHT). The full scope of molecular mechanisms governing this process remains unclear. The NR4A subfamily of orphan nuclear receptors act as tumor suppressors in myeloid leukemogenesis and have never been implicated in HSC specification.
View Article and Find Full Text PDFStem Cell Reports
December 2024
Department of Cell Differentiation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan. Electronic address:
Hematopoietic stem cells (HSCs) develop from hemogenic endothelial cells (HECs) during mouse embryogenesis. Understanding the signaling molecules required for HSC development is crucial for the in vitro derivation of HSCs. We previously induced HSCs from embryonic HECs, isolated at embryonic day 10.
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