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Return to the hematopoietic stem cell origin.

Samokhvalov IM - Cell Regen (Lond) (2012)

Bottom Line: Studying embryonic hematopoiesis is complicated by diversity of its locations in the constantly changing anatomy and by the mobility of blood cell precursors.Non-invasive in vivo cell tracing methodology offers a better insight into complex processes of blood cell specification.Realistic knowledge of the blood origin is critical for safe and efficient recapitulation of hematopoietic development in culture.

View Article: PubMed Central - PubMed

Affiliation: South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530 China.

ABSTRACT
Studying embryonic hematopoiesis is complicated by diversity of its locations in the constantly changing anatomy and by the mobility of blood cell precursors. Embryonic hematopoietic progenitors are identified in traditional in vivo and in vitro cell potential assays. Profound epigenetic plasticity of mammalian embryonic cells combined with significant inductive capacity of the potential assays suggest that our understanding of hematopoietic ontogenesis is substantially distorted. Non-invasive in vivo cell tracing methodology offers a better insight into complex processes of blood cell specification. In contrast to the widely accepted view based on the cell potential assays, the genetic tracing approach identified the yolk sac as the source of adult hematopoietic stem cell lineage. Realistic knowledge of the blood origin is critical for safe and efficient recapitulation of hematopoietic development in culture.

No MeSH data available.


Migration of blood cell precursors in the conceptus and the dynamics of their developmental potential. Red cells are shown by open circles. Fenestrated endothelium of fetal liver sinusoids promotes the entry of hematopoietic progenitors into the first extravascular niche.
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Fig3: Migration of blood cell precursors in the conceptus and the dynamics of their developmental potential. Red cells are shown by open circles. Fenestrated endothelium of fetal liver sinusoids promotes the entry of hematopoietic progenitors into the first extravascular niche.

Mentions: Current picture of the mammalian blood development was created using methods intended for studying adult hematopoiesis. It seems that most of controversies in developmental hematology arise from the excessive reliance on measuring cell potentials rather than cells fates. Unsettled epigenetic status of early embryonic cells makes them prone to show a variety of potentials which do not reflect the actual process of hematopoietic ontogenesis. Therefore, we can hardly attribute distinct hematopoietic phenotypes of adult hematology to hematopoietic precursors in the developing conceptus. Due to overbearing cell potential research, the role of the yolk sac in creation of HSC lineage was seriously underestimated by standard cell potential assays. As shown by the cell tracing studies, the proximal mesodermal masses of yolk sac may represent a unique cell population of the single hematopoietic origin in mammals. In the new emerging picture of hematopoietic ontogenesis the AGM region, umbilical/vitelline arteries and placental vasculature are not autonomous sources of definitive hematopoiesis. Instead, they operate as transient intravascular niches for developing HSC lineage (Figure 3). The first extravascular niche is formed within the fetal liver which functions as the first bona fide hematopoietic organ in mammalian ontogenesis.Figure 3


Return to the hematopoietic stem cell origin.

Samokhvalov IM - Cell Regen (Lond) (2012)

Migration of blood cell precursors in the conceptus and the dynamics of their developmental potential. Red cells are shown by open circles. Fenestrated endothelium of fetal liver sinusoids promotes the entry of hematopoietic progenitors into the first extravascular niche.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230910&req=5

Fig3: Migration of blood cell precursors in the conceptus and the dynamics of their developmental potential. Red cells are shown by open circles. Fenestrated endothelium of fetal liver sinusoids promotes the entry of hematopoietic progenitors into the first extravascular niche.
Mentions: Current picture of the mammalian blood development was created using methods intended for studying adult hematopoiesis. It seems that most of controversies in developmental hematology arise from the excessive reliance on measuring cell potentials rather than cells fates. Unsettled epigenetic status of early embryonic cells makes them prone to show a variety of potentials which do not reflect the actual process of hematopoietic ontogenesis. Therefore, we can hardly attribute distinct hematopoietic phenotypes of adult hematology to hematopoietic precursors in the developing conceptus. Due to overbearing cell potential research, the role of the yolk sac in creation of HSC lineage was seriously underestimated by standard cell potential assays. As shown by the cell tracing studies, the proximal mesodermal masses of yolk sac may represent a unique cell population of the single hematopoietic origin in mammals. In the new emerging picture of hematopoietic ontogenesis the AGM region, umbilical/vitelline arteries and placental vasculature are not autonomous sources of definitive hematopoiesis. Instead, they operate as transient intravascular niches for developing HSC lineage (Figure 3). The first extravascular niche is formed within the fetal liver which functions as the first bona fide hematopoietic organ in mammalian ontogenesis.Figure 3

Bottom Line: Studying embryonic hematopoiesis is complicated by diversity of its locations in the constantly changing anatomy and by the mobility of blood cell precursors.Non-invasive in vivo cell tracing methodology offers a better insight into complex processes of blood cell specification.Realistic knowledge of the blood origin is critical for safe and efficient recapitulation of hematopoietic development in culture.

View Article: PubMed Central - PubMed

Affiliation: South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530 China.

ABSTRACT
Studying embryonic hematopoiesis is complicated by diversity of its locations in the constantly changing anatomy and by the mobility of blood cell precursors. Embryonic hematopoietic progenitors are identified in traditional in vivo and in vitro cell potential assays. Profound epigenetic plasticity of mammalian embryonic cells combined with significant inductive capacity of the potential assays suggest that our understanding of hematopoietic ontogenesis is substantially distorted. Non-invasive in vivo cell tracing methodology offers a better insight into complex processes of blood cell specification. In contrast to the widely accepted view based on the cell potential assays, the genetic tracing approach identified the yolk sac as the source of adult hematopoietic stem cell lineage. Realistic knowledge of the blood origin is critical for safe and efficient recapitulation of hematopoietic development in culture.

No MeSH data available.