Limits...
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.


Related in: MedlinePlus

Mesodermal cell masses in the proximal yolk sac co-express Runx1 and VE-cadherin. Two upper panels show the flow cytometry analysis of pooled cells from eight E7.5-8.0 yolk sacs. Two lower panels demonstrate connection between the level of the Runx1 expression and the efficiency of cell labeling in the cell tracing studies [6].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4230910&req=5

Fig2: Mesodermal cell masses in the proximal yolk sac co-express Runx1 and VE-cadherin. Two upper panels show the flow cytometry analysis of pooled cells from eight E7.5-8.0 yolk sacs. Two lower panels demonstrate connection between the level of the Runx1 expression and the efficiency of cell labeling in the cell tracing studies [6].

Mentions: The proximal mesodermal cell masses recently were shown to coexpress a number of hematopoietic and endothelial markers [8, 72]. Practically all Gata1- and majority of Runx1-positive cells in the mesodermal masses at the neural plate stage transiently coexpress VE-cadherin [8, 72, 73], the most specific marker of endothelial lineage. Gata1 and Runx1 are the key transcription factors for erythroid and entire definitive hematopoietic development, respectively [74, 75]. Slightly later at E7.75 (head hold stage), an embryonic globin marker of primitive erythroblasts is also transiently co-expressed with VE-cadherin apparently in the nascent embryonic red blood cells. It is unclear what function, if any, VE-cadherin is playing in the developing hematopoietic lineage, but the co-expression of the hematopoietic factors with VE-cadherin in non-endothelial cells suggests that unique epigenetic changes happen during de novo hematopoiesis. VE-cadherin+Runx1+ cells were found to be the earliest definitive hematopoietic precursors [8] and the co-expression is sustained for some period of time - about half of Runx1+ YS cells are still VE-cadherin-positive at the neural fold stage (Figure 2). Interestingly, only about 25% of all Runx1-positive cells at the neural plate can be arbitrarily qualified as Runx1high (Figure 2) which underscores cell heterogeneity of the developing blood islands. It remains to be investigated whether the level of Runx1 expression has a functional significance, but the Runx1high cells as preferable targets for Cre-dependent recombination in the Runx1-based cell tracing (Figure 2) eventually develop into adult hematopoietic cells including dHSCs [6, 8].Figure 2


Return to the hematopoietic stem cell origin.

Samokhvalov IM - Cell Regen (Lond) (2012)

Mesodermal cell masses in the proximal yolk sac co-express Runx1 and VE-cadherin. Two upper panels show the flow cytometry analysis of pooled cells from eight E7.5-8.0 yolk sacs. Two lower panels demonstrate connection between the level of the Runx1 expression and the efficiency of cell labeling in the cell tracing studies [6].
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: Mesodermal cell masses in the proximal yolk sac co-express Runx1 and VE-cadherin. Two upper panels show the flow cytometry analysis of pooled cells from eight E7.5-8.0 yolk sacs. Two lower panels demonstrate connection between the level of the Runx1 expression and the efficiency of cell labeling in the cell tracing studies [6].
Mentions: The proximal mesodermal cell masses recently were shown to coexpress a number of hematopoietic and endothelial markers [8, 72]. Practically all Gata1- and majority of Runx1-positive cells in the mesodermal masses at the neural plate stage transiently coexpress VE-cadherin [8, 72, 73], the most specific marker of endothelial lineage. Gata1 and Runx1 are the key transcription factors for erythroid and entire definitive hematopoietic development, respectively [74, 75]. Slightly later at E7.75 (head hold stage), an embryonic globin marker of primitive erythroblasts is also transiently co-expressed with VE-cadherin apparently in the nascent embryonic red blood cells. It is unclear what function, if any, VE-cadherin is playing in the developing hematopoietic lineage, but the co-expression of the hematopoietic factors with VE-cadherin in non-endothelial cells suggests that unique epigenetic changes happen during de novo hematopoiesis. VE-cadherin+Runx1+ cells were found to be the earliest definitive hematopoietic precursors [8] and the co-expression is sustained for some period of time - about half of Runx1+ YS cells are still VE-cadherin-positive at the neural fold stage (Figure 2). Interestingly, only about 25% of all Runx1-positive cells at the neural plate can be arbitrarily qualified as Runx1high (Figure 2) which underscores cell heterogeneity of the developing blood islands. It remains to be investigated whether the level of Runx1 expression has a functional significance, but the Runx1high cells as preferable targets for Cre-dependent recombination in the Runx1-based cell tracing (Figure 2) eventually develop into adult hematopoietic cells including dHSCs [6, 8].Figure 2

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.


Related in: MedlinePlus