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Fetal hematopoietic stem cells express MFG-E8 during mouse embryogenesis.

Lee J, Choi BI, Park SY, An SY, Han J, Kim JH - Exp. Mol. Med. (2015)

Bottom Line: Using immunohistochemistry, we showed that MFG-E8 was specifically expressed in CD34(+) HSCs at all hematopoietic sites, including the yolk sac, aorta-gonad-mesonephros region, placenta and fetal liver, during embryogenesis.Fluorescence-activated cell sorting and polymerase chain reaction analyses demonstrated that CD34(+) cells, purified from the fetal liver, expressed additional HSC markers, c-Kit and Sca-1, and that these CD34(+) cells, but not CD34(-) cells, highly expressed MFG-E8.Together, this study demonstrates, for the first time, that MFG-8 is expressed in fetal HSC populations, and that MFG-E8 may have a role in embryonic hematopoiesis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Stem Cells and Tissue Regeneration, Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea.

ABSTRACT
The milk fat globule-EGF-factor 8 protein (MFG-E8) has been identified in various tissues, where it has an important role in intercellular interactions, cellular migration, and neovascularization. Previous studies showed that MFG-E8 is expressed in different cell types under normal and pathophysiological conditions, but its expression in hematopoietic stem cells (HSCs) during hematopoiesis has not been reported. In the present study, we investigated MFG-E8 expression in multiple hematopoietic tissues at different stages of mouse embryogenesis. Using immunohistochemistry, we showed that MFG-E8 was specifically expressed in CD34(+) HSCs at all hematopoietic sites, including the yolk sac, aorta-gonad-mesonephros region, placenta and fetal liver, during embryogenesis. Fluorescence-activated cell sorting and polymerase chain reaction analyses demonstrated that CD34(+) cells, purified from the fetal liver, expressed additional HSC markers, c-Kit and Sca-1, and that these CD34(+) cells, but not CD34(-) cells, highly expressed MFG-E8. We also found that MFG-E8 was not expressed in HSCs in adult mouse bone marrow, and that its expression was confined to F4/80(+) macrophages. Together, this study demonstrates, for the first time, that MFG-8 is expressed in fetal HSC populations, and that MFG-E8 may have a role in embryonic hematopoiesis.

No MeSH data available.


Related in: MedlinePlus

Milk fat globule-EGF-factor 8 (MFG-E8) expression in adult bone marrow. (a) Immunohistochemical analysis of bone marrow sections with antibodies against c-kit and MFG-E8. Note that c-kit+ cells are located in the near sinusoids and these cells did not express MFG-E8. S, sinusoid. Enlarged images of the boxed region are shown in the upper right corner of each panel. (b) Expression of MFG-E8 in F4/80+ macrophages in the bone marrow of adult mice. Scale bar: a=50 μm; b=20 μm.
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fig5: Milk fat globule-EGF-factor 8 (MFG-E8) expression in adult bone marrow. (a) Immunohistochemical analysis of bone marrow sections with antibodies against c-kit and MFG-E8. Note that c-kit+ cells are located in the near sinusoids and these cells did not express MFG-E8. S, sinusoid. Enlarged images of the boxed region are shown in the upper right corner of each panel. (b) Expression of MFG-E8 in F4/80+ macrophages in the bone marrow of adult mice. Scale bar: a=50 μm; b=20 μm.

Mentions: To maintain the number of HSCs, hematopoiesis occurs mainly in the bone marrow throughout adult life.18 Because CD34 expression is known to be downregulated in adult HSCs, we used c-Kit, another marker of HSCs, to examine expression of MFG-E8 in mouse femur bone marrow (Supplementary Figure 3).38 Immunohistochemical analysis of bone marrow sections showed that adult c-Kit+ HSCs were located near the lining of sinusoids as previously reported,39 but MFG-E8 expression was not detected in c-Kit+ HSCs (Figure 5a). Because MFG-E8 expression in macrophages has been previously reported,13 we flushed bone marrow cells and assessed the expression of MFG-E8, on cytospin slides. This procedure allowed us to determine that MFG-E8 was only detected in cells expressing F4/80, a marker of mature macrophages. None of the other cells flushed out of the bone marrow expressed MFG-E8 (Figure 5b).


Fetal hematopoietic stem cells express MFG-E8 during mouse embryogenesis.

Lee J, Choi BI, Park SY, An SY, Han J, Kim JH - Exp. Mol. Med. (2015)

Milk fat globule-EGF-factor 8 (MFG-E8) expression in adult bone marrow. (a) Immunohistochemical analysis of bone marrow sections with antibodies against c-kit and MFG-E8. Note that c-kit+ cells are located in the near sinusoids and these cells did not express MFG-E8. S, sinusoid. Enlarged images of the boxed region are shown in the upper right corner of each panel. (b) Expression of MFG-E8 in F4/80+ macrophages in the bone marrow of adult mice. Scale bar: a=50 μm; b=20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4525298&req=5

fig5: Milk fat globule-EGF-factor 8 (MFG-E8) expression in adult bone marrow. (a) Immunohistochemical analysis of bone marrow sections with antibodies against c-kit and MFG-E8. Note that c-kit+ cells are located in the near sinusoids and these cells did not express MFG-E8. S, sinusoid. Enlarged images of the boxed region are shown in the upper right corner of each panel. (b) Expression of MFG-E8 in F4/80+ macrophages in the bone marrow of adult mice. Scale bar: a=50 μm; b=20 μm.
Mentions: To maintain the number of HSCs, hematopoiesis occurs mainly in the bone marrow throughout adult life.18 Because CD34 expression is known to be downregulated in adult HSCs, we used c-Kit, another marker of HSCs, to examine expression of MFG-E8 in mouse femur bone marrow (Supplementary Figure 3).38 Immunohistochemical analysis of bone marrow sections showed that adult c-Kit+ HSCs were located near the lining of sinusoids as previously reported,39 but MFG-E8 expression was not detected in c-Kit+ HSCs (Figure 5a). Because MFG-E8 expression in macrophages has been previously reported,13 we flushed bone marrow cells and assessed the expression of MFG-E8, on cytospin slides. This procedure allowed us to determine that MFG-E8 was only detected in cells expressing F4/80, a marker of mature macrophages. None of the other cells flushed out of the bone marrow expressed MFG-E8 (Figure 5b).

Bottom Line: Using immunohistochemistry, we showed that MFG-E8 was specifically expressed in CD34(+) HSCs at all hematopoietic sites, including the yolk sac, aorta-gonad-mesonephros region, placenta and fetal liver, during embryogenesis.Fluorescence-activated cell sorting and polymerase chain reaction analyses demonstrated that CD34(+) cells, purified from the fetal liver, expressed additional HSC markers, c-Kit and Sca-1, and that these CD34(+) cells, but not CD34(-) cells, highly expressed MFG-E8.Together, this study demonstrates, for the first time, that MFG-8 is expressed in fetal HSC populations, and that MFG-E8 may have a role in embryonic hematopoiesis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Stem Cells and Tissue Regeneration, Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea.

ABSTRACT
The milk fat globule-EGF-factor 8 protein (MFG-E8) has been identified in various tissues, where it has an important role in intercellular interactions, cellular migration, and neovascularization. Previous studies showed that MFG-E8 is expressed in different cell types under normal and pathophysiological conditions, but its expression in hematopoietic stem cells (HSCs) during hematopoiesis has not been reported. In the present study, we investigated MFG-E8 expression in multiple hematopoietic tissues at different stages of mouse embryogenesis. Using immunohistochemistry, we showed that MFG-E8 was specifically expressed in CD34(+) HSCs at all hematopoietic sites, including the yolk sac, aorta-gonad-mesonephros region, placenta and fetal liver, during embryogenesis. Fluorescence-activated cell sorting and polymerase chain reaction analyses demonstrated that CD34(+) cells, purified from the fetal liver, expressed additional HSC markers, c-Kit and Sca-1, and that these CD34(+) cells, but not CD34(-) cells, highly expressed MFG-E8. We also found that MFG-E8 was not expressed in HSCs in adult mouse bone marrow, and that its expression was confined to F4/80(+) macrophages. Together, this study demonstrates, for the first time, that MFG-8 is expressed in fetal HSC populations, and that MFG-E8 may have a role in embryonic hematopoiesis.

No MeSH data available.


Related in: MedlinePlus