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Mouse placenta is a major hematopoietic organ
Marcio Alvarez-Silva1, Patricia Belo-Diabangouaya, Josselyne Salaün
1Laboratoire d'Embryologie cellulaire et moléculaire du CNRS et du Collège de France, 49 bis, avenue de la Belle Gabrielle, 94736 Nogent s/Marne cedex, France.
Development (Cambridge, England)
|September 26, 2003
Summary
The placenta and yolk sac are early sites of hematopoietic stem and progenitor cell development in mice. These organs contain clonogenic progenitors crucial for blood formation throughout pregnancy.
Area of Science:
- Developmental biology
- Hematopoiesis
- Stem cell research
Background:
- Hematopoietic stem cells (HSCs) originate early in embryonic development.
- The roles of extraembryonic organs in early hematopoiesis are not fully understood.
Purpose of the Study:
- To investigate the presence and characteristics of in vitro clonogenic hematopoietic progenitors in the mouse placenta and yolk sac during early embryonic development.
- To compare the hematopoietic potential of the placenta and yolk sac with the fetal liver.
Main Methods:
- Analysis of placenta, yolk sac, embryonic body, and fetal liver from mouse embryos (E8-E17) for clonogenic progenitors.
- In vitro culture of progenitor cells to assess colony formation and multilineage potential.
- Use of GFP transgenic embryos to trace the origin of placental hematopoietic cells.
Main Results:
- Hematopoietic progenitors first appear in the yolk sac (E8.5), embryonic body (E8.5), and placenta (E8.5), with the fetal liver showing progenitors later (E12).
- The placenta harbors a higher frequency of early progenitors yielding multilineage colonies compared to the yolk sac and fetal liver.
- Placental colonies are predominantly of fetal origin (80%), indicating the placenta's role as a hematopoietic organ.
Conclusions:
- The placenta is a significant hematopoietic organ active throughout most of pregnancy.
- The placenta and yolk sac exhibit distinct hematopoietic developmental profiles compared to the fetal liver.
- Early embryonic hematopoietic stem and progenitor cells are present in the placenta and yolk sac, contributing to fetal blood formation.