HSC-Independent Definitive Hematopoiesis Persists Into Adult Life

Authors

Michihiro Kobayashi
Haichao Wei
Takashi Yamanashi
Nathalia Azevedo Portilho
Samuel Cornelius
Noemi Valiente
Chika Nishida
Haizi Cheng
Augusto Latorre
W Jim Zheng
Joonsoo Kang
Jun Seita
David J Shih
Jia Qian Wu
Momoko Yoshimoto

Publication Date

3-28-2023

Journal

Cell Reports

Abstract

It is widely believed that hematopoiesis after birth is established by hematopoietic stem cells (HSCs) in the bone marrow and that HSC-independent hematopoiesis is limited only to primitive erythro-myeloid cells and tissue-resident innate immune cells arising in the embryo. Here, surprisingly, we find that significant percentages of lymphocytes are not derived from HSCs, even in 1-year-old mice. Instead, multiple waves of hematopoiesis occur from embryonic day 7.5 (E7.5) to E11.5 endothelial cells, which simultaneously produce HSCs and lymphoid progenitors that constitute many layers of adaptive T and B lymphocytes in adult mice. Additionally, HSC lineage tracing reveals that the contribution of fetal liver HSCs to peritoneal B-1a cells is minimal and that the majority of B-1a cells are HSC independent. Our discovery of extensive HSC-independent lymphocytes in adult mice attests to the complex blood developmental dynamics spanning the embryo-to-adult transition and challenges the paradigm of HSCs exclusively underpinning the postnatal immune system.

Keywords

Animals, Mice, Endothelial Cells, Cell Lineage, Hematopoietic Stem Cells, Bone Marrow, Hematopoiesis

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Supplementary Materials

PMID: 36906851