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- Azzoni, Emanuele, et al.
(author)
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The onset of circulation triggers a metabolic switch required for endothelial to hematopoietic transition
- 2021
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In: Cell Reports. - : Elsevier BV. - 2211-1247. ; 37:11
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Journal article (peer-reviewed)abstract
- Hematopoietic stem cells (HSCs) emerge during development from the vascular wall of the main embryonic arteries. The onset of circulation triggers several processes that provide critical external factors for HSC generation. Nevertheless, it is not fully understood how and when the onset of circulation affects HSC emergence. Here we show that in Ncx1−/− mouse embryos devoid of circulation the HSC lineage develops until the phenotypic pro-HSC stage. However, these cells reside in an abnormal microenvironment, fail to activate the hematopoietic program downstream of Runx1, and are functionally impaired. Single-cell transcriptomics shows that during the endothelial-to-hematopoietic transition, Ncx1−/− cells fail to undergo a glycolysis to oxidative phosphorylation metabolic switch present in wild-type cells. Interestingly, experimental activation of glycolysis results in decreased intraembryonic hematopoiesis. Our results suggest that the onset of circulation triggers metabolic changes that allow HSC generation to proceed.
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- Böiers, Charlotta, et al.
(author)
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Lymphomyeloid Contribution of an Immune-Restricted Progenitor Emerging Prior to Definitive Hematopoietic Stem Cells.
- 2013
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In: Cell Stem Cell. - : Elsevier BV. - 1934-5909 .- 1875-9777. ; 13:5, s. 535-548
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Journal article (peer-reviewed)abstract
- In jawed vertebrates, development of an adaptive immune-system is essential for protection of the born organism against otherwise life-threatening pathogens. Myeloid cells of the innate immune system are formed early in development, whereas lymphopoiesis has been suggested to initiate much later, following emergence of definitive hematopoietic stem cells (HSCs). Herein, we demonstrate that the embryonic lymphoid commitment process initiates earlier than previously appreciated, prior to emergence of definitive HSCs, through establishment of a previously unrecognized entirely immune-restricted and lymphoid-primed progenitor. Notably, this immune-restricted progenitor appears to first emerge in the yolk sac and contributes physiologically to the establishment of lymphoid and some myeloid components of the immune-system, establishing the lymphomyeloid lineage restriction process as an early and physiologically important lineage-commitment step in mammalian hematopoiesis.
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- Luis, Tiago C., et al.
(author)
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Initial seeding of the embryonic thymus by immune-restricted lympho-myeloid progenitors
- 2016
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In: Nature Immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 17:12, s. 1424-1435
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Journal article (peer-reviewed)abstract
- The final stages of restriction to the T cell lineage occur in the thymus after the entry of thymus-seeding progenitors (TSPs). The identity and lineage potential of TSPs remains unclear. Because the first embryonic TSPs enter a non-vascularized thymic rudiment, we were able to directly image and establish the functional and molecular properties of embryonic thymopoiesis-initiating progenitors (T-IPs) before their entry into the thymus and activation of Notch signaling. T-IPs did not include multipotent stem cells or molecular evidence of T cell-restricted progenitors. Instead, single-cell molecular and functional analysis demonstrated that most fetal T-IPs expressed genes of and had the potential to develop into lymphoid as well as myeloid components of the immune system. Moreover, studies of embryos deficient in the transcriptional regulator RBPJ demonstrated that canonical Notch signaling was not involved in pre-thymic restriction to the T cell lineage or the migration of T-IPs.
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